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llvm-project/clang/lib/Sema/SemaTemplate.cpp

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//===------- SemaTemplate.cpp - Semantic Analysis for C++ Templates -------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//===----------------------------------------------------------------------===//
//
// This file implements semantic analysis for C++ templates.
//===----------------------------------------------------------------------===//
#include "TreeTransform.h"
#include "clang/AST/ASTConsumer.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclFriend.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/AST/TemplateName.h"
#include "clang/AST/TypeVisitor.h"
#include "clang/Basic/Builtins.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/PartialDiagnostic.h"
#include "clang/Basic/Stack.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Sema/DeclSpec.h"
#include "clang/Sema/Initialization.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/Overload.h"
#include "clang/Sema/ParsedTemplate.h"
#include "clang/Sema/Scope.h"
#include "clang/Sema/SemaInternal.h"
#include "clang/Sema/Template.h"
#include "clang/Sema/TemplateDeduction.h"
#include "llvm/ADT/SmallBitVector.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
#include <iterator>
using namespace clang;
using namespace sema;
// Exported for use by Parser.
SourceRange
clang::getTemplateParamsRange(TemplateParameterList const * const *Ps,
unsigned N) {
if (!N) return SourceRange();
return SourceRange(Ps[0]->getTemplateLoc(), Ps[N-1]->getRAngleLoc());
}
unsigned Sema::getTemplateDepth(Scope *S) const {
unsigned Depth = 0;
// Each template parameter scope represents one level of template parameter
// depth.
for (Scope *TempParamScope = S->getTemplateParamParent(); TempParamScope;
TempParamScope = TempParamScope->getParent()->getTemplateParamParent()) {
++Depth;
}
// Note that there are template parameters with the given depth.
auto ParamsAtDepth = [&](unsigned D) { Depth = std::max(Depth, D + 1); };
// Look for parameters of an enclosing generic lambda. We don't create a
// template parameter scope for these.
for (FunctionScopeInfo *FSI : getFunctionScopes()) {
if (auto *LSI = dyn_cast<LambdaScopeInfo>(FSI)) {
if (!LSI->TemplateParams.empty()) {
ParamsAtDepth(LSI->AutoTemplateParameterDepth);
break;
}
if (LSI->GLTemplateParameterList) {
ParamsAtDepth(LSI->GLTemplateParameterList->getDepth());
break;
}
}
}
// Look for parameters of an enclosing terse function template. We don't
// create a template parameter scope for these either.
for (const InventedTemplateParameterInfo &Info :
getInventedParameterInfos()) {
if (!Info.TemplateParams.empty()) {
ParamsAtDepth(Info.AutoTemplateParameterDepth);
break;
}
}
return Depth;
}
/// \brief Determine whether the declaration found is acceptable as the name
/// of a template and, if so, return that template declaration. Otherwise,
/// returns null.
///
/// Note that this may return an UnresolvedUsingValueDecl if AllowDependent
/// is true. In all other cases it will return a TemplateDecl (or null).
NamedDecl *Sema::getAsTemplateNameDecl(NamedDecl *D,
bool AllowFunctionTemplates,
bool AllowDependent) {
D = D->getUnderlyingDecl();
if (isa<TemplateDecl>(D)) {
if (!AllowFunctionTemplates && isa<FunctionTemplateDecl>(D))
return nullptr;
return D;
}
if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
// C++ [temp.local]p1:
// Like normal (non-template) classes, class templates have an
// injected-class-name (Clause 9). The injected-class-name
// can be used with or without a template-argument-list. When
// it is used without a template-argument-list, it is
// equivalent to the injected-class-name followed by the
// template-parameters of the class template enclosed in
// <>. When it is used with a template-argument-list, it
// refers to the specified class template specialization,
// which could be the current specialization or another
// specialization.
if (Record->isInjectedClassName()) {
Record = cast<CXXRecordDecl>(Record->getDeclContext());
if (Record->getDescribedClassTemplate())
return Record->getDescribedClassTemplate();
if (ClassTemplateSpecializationDecl *Spec
= dyn_cast<ClassTemplateSpecializationDecl>(Record))
return Spec->getSpecializedTemplate();
}
return nullptr;
}
// 'using Dependent::foo;' can resolve to a template name.
// 'using typename Dependent::foo;' cannot (not even if 'foo' is an
// injected-class-name).
if (AllowDependent && isa<UnresolvedUsingValueDecl>(D))
return D;
return nullptr;
}
void Sema::FilterAcceptableTemplateNames(LookupResult &R,
bool AllowFunctionTemplates,
bool AllowDependent) {
LookupResult::Filter filter = R.makeFilter();
while (filter.hasNext()) {
NamedDecl *Orig = filter.next();
if (!getAsTemplateNameDecl(Orig, AllowFunctionTemplates, AllowDependent))
filter.erase();
}
filter.done();
}
bool Sema::hasAnyAcceptableTemplateNames(LookupResult &R,
bool AllowFunctionTemplates,
bool AllowDependent,
bool AllowNonTemplateFunctions) {
for (LookupResult::iterator I = R.begin(), IEnd = R.end(); I != IEnd; ++I) {
if (getAsTemplateNameDecl(*I, AllowFunctionTemplates, AllowDependent))
return true;
if (AllowNonTemplateFunctions &&
isa<FunctionDecl>((*I)->getUnderlyingDecl()))
return true;
}
return false;
}
TemplateNameKind Sema::isTemplateName(Scope *S,
CXXScopeSpec &SS,
bool hasTemplateKeyword,
const UnqualifiedId &Name,
ParsedType ObjectTypePtr,
bool EnteringContext,
TemplateTy &TemplateResult,
bool &MemberOfUnknownSpecialization,
bool Disambiguation) {
assert(getLangOpts().CPlusPlus && "No template names in C!");
DeclarationName TName;
MemberOfUnknownSpecialization = false;
switch (Name.getKind()) {
case UnqualifiedIdKind::IK_Identifier:
TName = DeclarationName(Name.Identifier);
break;
case UnqualifiedIdKind::IK_OperatorFunctionId:
TName = Context.DeclarationNames.getCXXOperatorName(
Name.OperatorFunctionId.Operator);
break;
case UnqualifiedIdKind::IK_LiteralOperatorId:
TName = Context.DeclarationNames.getCXXLiteralOperatorName(Name.Identifier);
break;
default:
return TNK_Non_template;
}
QualType ObjectType = ObjectTypePtr.get();
AssumedTemplateKind AssumedTemplate;
LookupResult R(*this, TName, Name.getBeginLoc(), LookupOrdinaryName);
if (LookupTemplateName(R, S, SS, ObjectType, EnteringContext,
MemberOfUnknownSpecialization, SourceLocation(),
&AssumedTemplate,
/*AllowTypoCorrection=*/!Disambiguation))
return TNK_Non_template;
if (AssumedTemplate != AssumedTemplateKind::None) {
TemplateResult = TemplateTy::make(Context.getAssumedTemplateName(TName));
// Let the parser know whether we found nothing or found functions; if we
// found nothing, we want to more carefully check whether this is actually
// a function template name versus some other kind of undeclared identifier.
return AssumedTemplate == AssumedTemplateKind::FoundNothing
? TNK_Undeclared_template
: TNK_Function_template;
}
if (R.empty())
return TNK_Non_template;
NamedDecl *D = nullptr;
UsingShadowDecl *FoundUsingShadow = dyn_cast<UsingShadowDecl>(*R.begin());
if (R.isAmbiguous()) {
// If we got an ambiguity involving a non-function template, treat this
// as a template name, and pick an arbitrary template for error recovery.
bool AnyFunctionTemplates = false;
for (NamedDecl *FoundD : R) {
if (NamedDecl *FoundTemplate = getAsTemplateNameDecl(FoundD)) {
if (isa<FunctionTemplateDecl>(FoundTemplate))
AnyFunctionTemplates = true;
else {
D = FoundTemplate;
FoundUsingShadow = dyn_cast<UsingShadowDecl>(FoundD);
break;
}
}
}
// If we didn't find any templates at all, this isn't a template name.
// Leave the ambiguity for a later lookup to diagnose.
if (!D && !AnyFunctionTemplates) {
R.suppressDiagnostics();
return TNK_Non_template;
}
// If the only templates were function templates, filter out the rest.
// We'll diagnose the ambiguity later.
if (!D)
FilterAcceptableTemplateNames(R);
}
// At this point, we have either picked a single template name declaration D
// or we have a non-empty set of results R containing either one template name
// declaration or a set of function templates.
TemplateName Template;
TemplateNameKind TemplateKind;
unsigned ResultCount = R.end() - R.begin();
if (!D && ResultCount > 1) {
// We assume that we'll preserve the qualifier from a function
// template name in other ways.
Template = Context.getOverloadedTemplateName(R.begin(), R.end());
TemplateKind = TNK_Function_template;
// We'll do this lookup again later.
R.suppressDiagnostics();
} else {
if (!D) {
D = getAsTemplateNameDecl(*R.begin());
assert(D && "unambiguous result is not a template name");
}
if (isa<UnresolvedUsingValueDecl>(D)) {
// We don't yet know whether this is a template-name or not.
MemberOfUnknownSpecialization = true;
return TNK_Non_template;
}
TemplateDecl *TD = cast<TemplateDecl>(D);
if (SS.isSet() && !SS.isInvalid()) {
NestedNameSpecifier *Qualifier = SS.getScopeRep();
// FIXME: store the using TemplateName in QualifiedTemplateName if
// the TD is referred via a using-declaration.
Template =
Context.getQualifiedTemplateName(Qualifier, hasTemplateKeyword, TD);
} else {
Template =
FoundUsingShadow ? TemplateName(FoundUsingShadow) : TemplateName(TD);
assert(!FoundUsingShadow || FoundUsingShadow->getTargetDecl() == TD);
}
if (isa<FunctionTemplateDecl>(TD)) {
TemplateKind = TNK_Function_template;
// We'll do this lookup again later.
R.suppressDiagnostics();
} else {
assert(isa<ClassTemplateDecl>(TD) || isa<TemplateTemplateParmDecl>(TD) ||
isa<TypeAliasTemplateDecl>(TD) || isa<VarTemplateDecl>(TD) ||
isa<BuiltinTemplateDecl>(TD) || isa<ConceptDecl>(TD));
TemplateKind =
isa<VarTemplateDecl>(TD) ? TNK_Var_template :
isa<ConceptDecl>(TD) ? TNK_Concept_template :
TNK_Type_template;
}
}
TemplateResult = TemplateTy::make(Template);
return TemplateKind;
}
bool Sema::isDeductionGuideName(Scope *S, const IdentifierInfo &Name,
SourceLocation NameLoc,
ParsedTemplateTy *Template) {
CXXScopeSpec SS;
bool MemberOfUnknownSpecialization = false;
// We could use redeclaration lookup here, but we don't need to: the
// syntactic form of a deduction guide is enough to identify it even
// if we can't look up the template name at all.
LookupResult R(*this, DeclarationName(&Name), NameLoc, LookupOrdinaryName);
if (LookupTemplateName(R, S, SS, /*ObjectType*/ QualType(),
/*EnteringContext*/ false,
MemberOfUnknownSpecialization))
return false;
if (R.empty()) return false;
if (R.isAmbiguous()) {
// FIXME: Diagnose an ambiguity if we find at least one template.
R.suppressDiagnostics();
return false;
}
// We only treat template-names that name type templates as valid deduction
// guide names.
TemplateDecl *TD = R.getAsSingle<TemplateDecl>();
if (!TD || !getAsTypeTemplateDecl(TD))
return false;
if (Template)
*Template = TemplateTy::make(TemplateName(TD));
return true;
}
bool Sema::DiagnoseUnknownTemplateName(const IdentifierInfo &II,
SourceLocation IILoc,
Scope *S,
const CXXScopeSpec *SS,
TemplateTy &SuggestedTemplate,
TemplateNameKind &SuggestedKind) {
// We can't recover unless there's a dependent scope specifier preceding the
// template name.
// FIXME: Typo correction?
if (!SS || !SS->isSet() || !isDependentScopeSpecifier(*SS) ||
computeDeclContext(*SS))
return false;
// The code is missing a 'template' keyword prior to the dependent template
// name.
NestedNameSpecifier *Qualifier = (NestedNameSpecifier*)SS->getScopeRep();
Diag(IILoc, diag::err_template_kw_missing)
<< Qualifier << II.getName()
<< FixItHint::CreateInsertion(IILoc, "template ");
SuggestedTemplate
= TemplateTy::make(Context.getDependentTemplateName(Qualifier, &II));
SuggestedKind = TNK_Dependent_template_name;
return true;
}
bool Sema::LookupTemplateName(LookupResult &Found,
Scope *S, CXXScopeSpec &SS,
QualType ObjectType,
bool EnteringContext,
bool &MemberOfUnknownSpecialization,
RequiredTemplateKind RequiredTemplate,
AssumedTemplateKind *ATK,
bool AllowTypoCorrection) {
if (ATK)
*ATK = AssumedTemplateKind::None;
if (SS.isInvalid())
return true;
Found.setTemplateNameLookup(true);
// Determine where to perform name lookup
MemberOfUnknownSpecialization = false;
DeclContext *LookupCtx = nullptr;
bool IsDependent = false;
if (!ObjectType.isNull()) {
// This nested-name-specifier occurs in a member access expression, e.g.,
// x->B::f, and we are looking into the type of the object.
assert(SS.isEmpty() && "ObjectType and scope specifier cannot coexist");
LookupCtx = computeDeclContext(ObjectType);
IsDependent = !LookupCtx && ObjectType->isDependentType();
assert((IsDependent || !ObjectType->isIncompleteType() ||
ObjectType->castAs<TagType>()->isBeingDefined()) &&
"Caller should have completed object type");
// Template names cannot appear inside an Objective-C class or object type
// or a vector type.
//
// FIXME: This is wrong. For example:
//
// template<typename T> using Vec = T __attribute__((ext_vector_type(4)));
// Vec<int> vi;
// vi.Vec<int>::~Vec<int>();
//
// ... should be accepted but we will not treat 'Vec' as a template name
// here. The right thing to do would be to check if the name is a valid
// vector component name, and look up a template name if not. And similarly
// for lookups into Objective-C class and object types, where the same
// problem can arise.
if (ObjectType->isObjCObjectOrInterfaceType() ||
ObjectType->isVectorType()) {
Found.clear();
return false;
}
} else if (SS.isNotEmpty()) {
// This nested-name-specifier occurs after another nested-name-specifier,
// so long into the context associated with the prior nested-name-specifier.
LookupCtx = computeDeclContext(SS, EnteringContext);
IsDependent = !LookupCtx && isDependentScopeSpecifier(SS);
// The declaration context must be complete.
if (LookupCtx && RequireCompleteDeclContext(SS, LookupCtx))
return true;
}
bool ObjectTypeSearchedInScope = false;
bool AllowFunctionTemplatesInLookup = true;
if (LookupCtx) {
// Perform "qualified" name lookup into the declaration context we
// computed, which is either the type of the base of a member access
// expression or the declaration context associated with a prior
// nested-name-specifier.
LookupQualifiedName(Found, LookupCtx);
// FIXME: The C++ standard does not clearly specify what happens in the
// case where the object type is dependent, and implementations vary. In
// Clang, we treat a name after a . or -> as a template-name if lookup
// finds a non-dependent member or member of the current instantiation that
// is a type template, or finds no such members and lookup in the context
// of the postfix-expression finds a type template. In the latter case, the
// name is nonetheless dependent, and we may resolve it to a member of an
// unknown specialization when we come to instantiate the template.
IsDependent |= Found.wasNotFoundInCurrentInstantiation();
}
if (SS.isEmpty() && (ObjectType.isNull() || Found.empty())) {
// C++ [basic.lookup.classref]p1:
// In a class member access expression (5.2.5), if the . or -> token is
// immediately followed by an identifier followed by a <, the
// identifier must be looked up to determine whether the < is the
// beginning of a template argument list (14.2) or a less-than operator.
// The identifier is first looked up in the class of the object
// expression. If the identifier is not found, it is then looked up in
// the context of the entire postfix-expression and shall name a class
// template.
if (S)
LookupName(Found, S);
if (!ObjectType.isNull()) {
// FIXME: We should filter out all non-type templates here, particularly
// variable templates and concepts. But the exclusion of alias templates
// and template template parameters is a wording defect.
AllowFunctionTemplatesInLookup = false;
ObjectTypeSearchedInScope = true;
}
IsDependent |= Found.wasNotFoundInCurrentInstantiation();
}
if (Found.isAmbiguous())
return false;
if (ATK && SS.isEmpty() && ObjectType.isNull() &&
!RequiredTemplate.hasTemplateKeyword()) {
// C++2a [temp.names]p2:
// A name is also considered to refer to a template if it is an
// unqualified-id followed by a < and name lookup finds either one or more
// functions or finds nothing.
//
// To keep our behavior consistent, we apply the "finds nothing" part in
// all language modes, and diagnose the empty lookup in ActOnCallExpr if we
// successfully form a call to an undeclared template-id.
bool AllFunctions =
getLangOpts().CPlusPlus20 && llvm::all_of(Found, [](NamedDecl *ND) {
return isa<FunctionDecl>(ND->getUnderlyingDecl());
});
if (AllFunctions || (Found.empty() && !IsDependent)) {
// If lookup found any functions, or if this is a name that can only be
// used for a function, then strongly assume this is a function
// template-id.
*ATK = (Found.empty() && Found.getLookupName().isIdentifier())
? AssumedTemplateKind::FoundNothing
: AssumedTemplateKind::FoundFunctions;
Found.clear();
return false;
}
}
if (Found.empty() && !IsDependent && AllowTypoCorrection) {
// If we did not find any names, and this is not a disambiguation, attempt
// to correct any typos.
DeclarationName Name = Found.getLookupName();
Found.clear();
// Simple filter callback that, for keywords, only accepts the C++ *_cast
DefaultFilterCCC FilterCCC{};
FilterCCC.WantTypeSpecifiers = false;
FilterCCC.WantExpressionKeywords = false;
FilterCCC.WantRemainingKeywords = false;
FilterCCC.WantCXXNamedCasts = true;
if (TypoCorrection Corrected =
CorrectTypo(Found.getLookupNameInfo(), Found.getLookupKind(), S,
&SS, FilterCCC, CTK_ErrorRecovery, LookupCtx)) {
if (auto *ND = Corrected.getFoundDecl())
Found.addDecl(ND);
FilterAcceptableTemplateNames(Found);
if (Found.isAmbiguous()) {
Found.clear();
} else if (!Found.empty()) {
Found.setLookupName(Corrected.getCorrection());
if (LookupCtx) {
std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
Name.getAsString() == CorrectedStr;
diagnoseTypo(Corrected, PDiag(diag::err_no_member_template_suggest)
<< Name << LookupCtx << DroppedSpecifier
<< SS.getRange());
} else {
diagnoseTypo(Corrected, PDiag(diag::err_no_template_suggest) << Name);
}
}
}
}
NamedDecl *ExampleLookupResult =
Found.empty() ? nullptr : Found.getRepresentativeDecl();
FilterAcceptableTemplateNames(Found, AllowFunctionTemplatesInLookup);
if (Found.empty()) {
if (IsDependent) {
MemberOfUnknownSpecialization = true;
return false;
}
// If a 'template' keyword was used, a lookup that finds only non-template
// names is an error.
if (ExampleLookupResult && RequiredTemplate) {
Diag(Found.getNameLoc(), diag::err_template_kw_refers_to_non_template)
<< Found.getLookupName() << SS.getRange()
<< RequiredTemplate.hasTemplateKeyword()
<< RequiredTemplate.getTemplateKeywordLoc();
Diag(ExampleLookupResult->getUnderlyingDecl()->getLocation(),
diag::note_template_kw_refers_to_non_template)
<< Found.getLookupName();
return true;
}
return false;
}
if (S && !ObjectType.isNull() && !ObjectTypeSearchedInScope &&
!getLangOpts().CPlusPlus11) {
// C++03 [basic.lookup.classref]p1:
// [...] If the lookup in the class of the object expression finds a
// template, the name is also looked up in the context of the entire
// postfix-expression and [...]
//
// Note: C++11 does not perform this second lookup.
LookupResult FoundOuter(*this, Found.getLookupName(), Found.getNameLoc(),
LookupOrdinaryName);
FoundOuter.setTemplateNameLookup(true);
LookupName(FoundOuter, S);
// FIXME: We silently accept an ambiguous lookup here, in violation of
// [basic.lookup]/1.
FilterAcceptableTemplateNames(FoundOuter, /*AllowFunctionTemplates=*/false);
NamedDecl *OuterTemplate;
if (FoundOuter.empty()) {
// - if the name is not found, the name found in the class of the
// object expression is used, otherwise
} else if (FoundOuter.isAmbiguous() || !FoundOuter.isSingleResult() ||
!(OuterTemplate =
getAsTemplateNameDecl(FoundOuter.getFoundDecl()))) {
// - if the name is found in the context of the entire
// postfix-expression and does not name a class template, the name
// found in the class of the object expression is used, otherwise
FoundOuter.clear();
} else if (!Found.isSuppressingDiagnostics()) {
// - if the name found is a class template, it must refer to the same
// entity as the one found in the class of the object expression,
// otherwise the program is ill-formed.
if (!Found.isSingleResult() ||
getAsTemplateNameDecl(Found.getFoundDecl())->getCanonicalDecl() !=
OuterTemplate->getCanonicalDecl()) {
Diag(Found.getNameLoc(),
diag::ext_nested_name_member_ref_lookup_ambiguous)
<< Found.getLookupName()
<< ObjectType;
Diag(Found.getRepresentativeDecl()->getLocation(),
diag::note_ambig_member_ref_object_type)
<< ObjectType;
Diag(FoundOuter.getFoundDecl()->getLocation(),
diag::note_ambig_member_ref_scope);
// Recover by taking the template that we found in the object
// expression's type.
}
}
}
return false;
}
void Sema::diagnoseExprIntendedAsTemplateName(Scope *S, ExprResult TemplateName,
SourceLocation Less,
SourceLocation Greater) {
if (TemplateName.isInvalid())
return;
DeclarationNameInfo NameInfo;
CXXScopeSpec SS;
LookupNameKind LookupKind;
DeclContext *LookupCtx = nullptr;
NamedDecl *Found = nullptr;
bool MissingTemplateKeyword = false;
// Figure out what name we looked up.
if (auto *DRE = dyn_cast<DeclRefExpr>(TemplateName.get())) {
NameInfo = DRE->getNameInfo();
SS.Adopt(DRE->getQualifierLoc());
LookupKind = LookupOrdinaryName;
Found = DRE->getFoundDecl();
} else if (auto *ME = dyn_cast<MemberExpr>(TemplateName.get())) {
NameInfo = ME->getMemberNameInfo();
SS.Adopt(ME->getQualifierLoc());
LookupKind = LookupMemberName;
LookupCtx = ME->getBase()->getType()->getAsCXXRecordDecl();
Found = ME->getMemberDecl();
} else if (auto *DSDRE =
dyn_cast<DependentScopeDeclRefExpr>(TemplateName.get())) {
NameInfo = DSDRE->getNameInfo();
SS.Adopt(DSDRE->getQualifierLoc());
MissingTemplateKeyword = true;
} else if (auto *DSME =
dyn_cast<CXXDependentScopeMemberExpr>(TemplateName.get())) {
NameInfo = DSME->getMemberNameInfo();
SS.Adopt(DSME->getQualifierLoc());
MissingTemplateKeyword = true;
} else {
llvm_unreachable("unexpected kind of potential template name");
}
// If this is a dependent-scope lookup, diagnose that the 'template' keyword
// was missing.
if (MissingTemplateKeyword) {
Diag(NameInfo.getBeginLoc(), diag::err_template_kw_missing)
<< "" << NameInfo.getName().getAsString() << SourceRange(Less, Greater);
return;
}
// Try to correct the name by looking for templates and C++ named casts.
struct TemplateCandidateFilter : CorrectionCandidateCallback {
Sema &S;
TemplateCandidateFilter(Sema &S) : S(S) {
WantTypeSpecifiers = false;
WantExpressionKeywords = false;
WantRemainingKeywords = false;
WantCXXNamedCasts = true;
};
bool ValidateCandidate(const TypoCorrection &Candidate) override {
if (auto *ND = Candidate.getCorrectionDecl())
return S.getAsTemplateNameDecl(ND);
return Candidate.isKeyword();
}
std::unique_ptr<CorrectionCandidateCallback> clone() override {
return std::make_unique<TemplateCandidateFilter>(*this);
}
};
DeclarationName Name = NameInfo.getName();
TemplateCandidateFilter CCC(*this);
if (TypoCorrection Corrected = CorrectTypo(NameInfo, LookupKind, S, &SS, CCC,
CTK_ErrorRecovery, LookupCtx)) {
auto *ND = Corrected.getFoundDecl();
if (ND)
ND = getAsTemplateNameDecl(ND);
if (ND || Corrected.isKeyword()) {
if (LookupCtx) {
std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
Name.getAsString() == CorrectedStr;
diagnoseTypo(Corrected,
PDiag(diag::err_non_template_in_member_template_id_suggest)
<< Name << LookupCtx << DroppedSpecifier
<< SS.getRange(), false);
} else {
diagnoseTypo(Corrected,
PDiag(diag::err_non_template_in_template_id_suggest)
<< Name, false);
}
if (Found)
Diag(Found->getLocation(),
diag::note_non_template_in_template_id_found);
return;
}
}
Diag(NameInfo.getLoc(), diag::err_non_template_in_template_id)
<< Name << SourceRange(Less, Greater);
if (Found)
Diag(Found->getLocation(), diag::note_non_template_in_template_id_found);
}
/// ActOnDependentIdExpression - Handle a dependent id-expression that
/// was just parsed. This is only possible with an explicit scope
/// specifier naming a dependent type.
ExprResult
Sema::ActOnDependentIdExpression(const CXXScopeSpec &SS,
SourceLocation TemplateKWLoc,
const DeclarationNameInfo &NameInfo,
bool isAddressOfOperand,
const TemplateArgumentListInfo *TemplateArgs) {
DeclContext *DC = getFunctionLevelDeclContext();
// C++11 [expr.prim.general]p12:
// An id-expression that denotes a non-static data member or non-static
// member function of a class can only be used:
// (...)
// - if that id-expression denotes a non-static data member and it
// appears in an unevaluated operand.
//
// If this might be the case, form a DependentScopeDeclRefExpr instead of a
// CXXDependentScopeMemberExpr. The former can instantiate to either
// DeclRefExpr or MemberExpr depending on lookup results, while the latter is
// always a MemberExpr.
bool MightBeCxx11UnevalField =
getLangOpts().CPlusPlus11 && isUnevaluatedContext();
// Check if the nested name specifier is an enum type.
bool IsEnum = false;
if (NestedNameSpecifier *NNS = SS.getScopeRep())
IsEnum = isa_and_nonnull<EnumType>(NNS->getAsType());
if (!MightBeCxx11UnevalField && !isAddressOfOperand && !IsEnum &&
isa<CXXMethodDecl>(DC) && cast<CXXMethodDecl>(DC)->isInstance()) {
QualType ThisType = cast<CXXMethodDecl>(DC)->getThisType();
// Since the 'this' expression is synthesized, we don't need to
// perform the double-lookup check.
NamedDecl *FirstQualifierInScope = nullptr;
return CXXDependentScopeMemberExpr::Create(
Context, /*This*/ nullptr, ThisType, /*IsArrow*/ true,
/*Op*/ SourceLocation(), SS.getWithLocInContext(Context), TemplateKWLoc,
FirstQualifierInScope, NameInfo, TemplateArgs);
}
return BuildDependentDeclRefExpr(SS, TemplateKWLoc, NameInfo, TemplateArgs);
}
ExprResult
Sema::BuildDependentDeclRefExpr(const CXXScopeSpec &SS,
SourceLocation TemplateKWLoc,
const DeclarationNameInfo &NameInfo,
const TemplateArgumentListInfo *TemplateArgs) {
// DependentScopeDeclRefExpr::Create requires a valid QualifierLoc
NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
if (!QualifierLoc)
return ExprError();
return DependentScopeDeclRefExpr::Create(
Context, QualifierLoc, TemplateKWLoc, NameInfo, TemplateArgs);
}
/// Determine whether we would be unable to instantiate this template (because
/// it either has no definition, or is in the process of being instantiated).
bool Sema::DiagnoseUninstantiableTemplate(SourceLocation PointOfInstantiation,
NamedDecl *Instantiation,
bool InstantiatedFromMember,
const NamedDecl *Pattern,
const NamedDecl *PatternDef,
TemplateSpecializationKind TSK,
bool Complain /*= true*/) {
assert(isa<TagDecl>(Instantiation) || isa<FunctionDecl>(Instantiation) ||
isa<VarDecl>(Instantiation));
bool IsEntityBeingDefined = false;
if (const TagDecl *TD = dyn_cast_or_null<TagDecl>(PatternDef))
IsEntityBeingDefined = TD->isBeingDefined();
if (PatternDef && !IsEntityBeingDefined) {
NamedDecl *SuggestedDef = nullptr;
if (!hasVisibleDefinition(const_cast<NamedDecl*>(PatternDef), &SuggestedDef,
/*OnlyNeedComplete*/false)) {
// If we're allowed to diagnose this and recover, do so.
bool Recover = Complain && !isSFINAEContext();
if (Complain)
diagnoseMissingImport(PointOfInstantiation, SuggestedDef,
Sema::MissingImportKind::Definition, Recover);
return !Recover;
}
return false;
}
if (!Complain || (PatternDef && PatternDef->isInvalidDecl()))
return true;
llvm::Optional<unsigned> Note;
QualType InstantiationTy;
if (TagDecl *TD = dyn_cast<TagDecl>(Instantiation))
InstantiationTy = Context.getTypeDeclType(TD);
if (PatternDef) {
Diag(PointOfInstantiation,
diag::err_template_instantiate_within_definition)
<< /*implicit|explicit*/(TSK != TSK_ImplicitInstantiation)
<< InstantiationTy;
// Not much point in noting the template declaration here, since
// we're lexically inside it.
Instantiation->setInvalidDecl();
} else if (InstantiatedFromMember) {
if (isa<FunctionDecl>(Instantiation)) {
Diag(PointOfInstantiation,
diag::err_explicit_instantiation_undefined_member)
<< /*member function*/ 1 << Instantiation->getDeclName()
<< Instantiation->getDeclContext();
Note = diag::note_explicit_instantiation_here;
} else {
assert(isa<TagDecl>(Instantiation) && "Must be a TagDecl!");
Diag(PointOfInstantiation,
diag::err_implicit_instantiate_member_undefined)
<< InstantiationTy;
Note = diag::note_member_declared_at;
}
} else {
if (isa<FunctionDecl>(Instantiation)) {
Diag(PointOfInstantiation,
diag::err_explicit_instantiation_undefined_func_template)
<< Pattern;
Note = diag::note_explicit_instantiation_here;
} else if (isa<TagDecl>(Instantiation)) {
Diag(PointOfInstantiation, diag::err_template_instantiate_undefined)
<< (TSK != TSK_ImplicitInstantiation)
<< InstantiationTy;
Note = diag::note_template_decl_here;
} else {
assert(isa<VarDecl>(Instantiation) && "Must be a VarDecl!");
if (isa<VarTemplateSpecializationDecl>(Instantiation)) {
Diag(PointOfInstantiation,
diag::err_explicit_instantiation_undefined_var_template)
<< Instantiation;
Instantiation->setInvalidDecl();
} else
Diag(PointOfInstantiation,
diag::err_explicit_instantiation_undefined_member)
<< /*static data member*/ 2 << Instantiation->getDeclName()
<< Instantiation->getDeclContext();
Note = diag::note_explicit_instantiation_here;
}
}
if (Note) // Diagnostics were emitted.
Diag(Pattern->getLocation(), Note.getValue());
// In general, Instantiation isn't marked invalid to get more than one
// error for multiple undefined instantiations. But the code that does
// explicit declaration -> explicit definition conversion can't handle
// invalid declarations, so mark as invalid in that case.
if (TSK == TSK_ExplicitInstantiationDeclaration)
Instantiation->setInvalidDecl();
return true;
}
/// DiagnoseTemplateParameterShadow - Produce a diagnostic complaining
/// that the template parameter 'PrevDecl' is being shadowed by a new
/// declaration at location Loc. Returns true to indicate that this is
/// an error, and false otherwise.
void Sema::DiagnoseTemplateParameterShadow(SourceLocation Loc, Decl *PrevDecl) {
assert(PrevDecl->isTemplateParameter() && "Not a template parameter");
// C++ [temp.local]p4:
// A template-parameter shall not be redeclared within its
// scope (including nested scopes).
//
// Make this a warning when MSVC compatibility is requested.
unsigned DiagId = getLangOpts().MSVCCompat ? diag::ext_template_param_shadow
: diag::err_template_param_shadow;
Diag(Loc, DiagId) << cast<NamedDecl>(PrevDecl)->getDeclName();
Diag(PrevDecl->getLocation(), diag::note_template_param_here);
}
/// AdjustDeclIfTemplate - If the given decl happens to be a template, reset
/// the parameter D to reference the templated declaration and return a pointer
/// to the template declaration. Otherwise, do nothing to D and return null.
TemplateDecl *Sema::AdjustDeclIfTemplate(Decl *&D) {
if (TemplateDecl *Temp = dyn_cast_or_null<TemplateDecl>(D)) {
D = Temp->getTemplatedDecl();
return Temp;
}
return nullptr;
}
ParsedTemplateArgument ParsedTemplateArgument::getTemplatePackExpansion(
SourceLocation EllipsisLoc) const {
assert(Kind == Template &&
"Only template template arguments can be pack expansions here");
assert(getAsTemplate().get().containsUnexpandedParameterPack() &&
"Template template argument pack expansion without packs");
ParsedTemplateArgument Result(*this);
Result.EllipsisLoc = EllipsisLoc;
return Result;
}
static TemplateArgumentLoc translateTemplateArgument(Sema &SemaRef,
const ParsedTemplateArgument &Arg) {
switch (Arg.getKind()) {
case ParsedTemplateArgument::Type: {
TypeSourceInfo *DI;
QualType T = SemaRef.GetTypeFromParser(Arg.getAsType(), &DI);
if (!DI)
DI = SemaRef.Context.getTrivialTypeSourceInfo(T, Arg.getLocation());
return TemplateArgumentLoc(TemplateArgument(T), DI);
}
case ParsedTemplateArgument::NonType: {
Expr *E = static_cast<Expr *>(Arg.getAsExpr());
return TemplateArgumentLoc(TemplateArgument(E), E);
}
case ParsedTemplateArgument::Template: {
TemplateName Template = Arg.getAsTemplate().get();
TemplateArgument TArg;
if (Arg.getEllipsisLoc().isValid())
TArg = TemplateArgument(Template, Optional<unsigned int>());
else
TArg = Template;
return TemplateArgumentLoc(
SemaRef.Context, TArg,
Arg.getScopeSpec().getWithLocInContext(SemaRef.Context),
Arg.getLocation(), Arg.getEllipsisLoc());
}
}
llvm_unreachable("Unhandled parsed template argument");
}
/// Translates template arguments as provided by the parser
/// into template arguments used by semantic analysis.
void Sema::translateTemplateArguments(const ASTTemplateArgsPtr &TemplateArgsIn,
TemplateArgumentListInfo &TemplateArgs) {
for (unsigned I = 0, Last = TemplateArgsIn.size(); I != Last; ++I)
TemplateArgs.addArgument(translateTemplateArgument(*this,
TemplateArgsIn[I]));
}
static void maybeDiagnoseTemplateParameterShadow(Sema &SemaRef, Scope *S,
SourceLocation Loc,
IdentifierInfo *Name) {
NamedDecl *PrevDecl = SemaRef.LookupSingleName(
S, Name, Loc, Sema::LookupOrdinaryName, Sema::ForVisibleRedeclaration);
if (PrevDecl && PrevDecl->isTemplateParameter())
SemaRef.DiagnoseTemplateParameterShadow(Loc, PrevDecl);
}
/// Convert a parsed type into a parsed template argument. This is mostly
/// trivial, except that we may have parsed a C++17 deduced class template
/// specialization type, in which case we should form a template template
/// argument instead of a type template argument.
ParsedTemplateArgument Sema::ActOnTemplateTypeArgument(TypeResult ParsedType) {
TypeSourceInfo *TInfo;
QualType T = GetTypeFromParser(ParsedType.get(), &TInfo);
if (T.isNull())
return ParsedTemplateArgument();
assert(TInfo && "template argument with no location");
// If we might have formed a deduced template specialization type, convert
// it to a template template argument.
if (getLangOpts().CPlusPlus17) {
TypeLoc TL = TInfo->getTypeLoc();
SourceLocation EllipsisLoc;
if (auto PET = TL.getAs<PackExpansionTypeLoc>()) {
EllipsisLoc = PET.getEllipsisLoc();
TL = PET.getPatternLoc();
}
CXXScopeSpec SS;
if (auto ET = TL.getAs<ElaboratedTypeLoc>()) {
SS.Adopt(ET.getQualifierLoc());
TL = ET.getNamedTypeLoc();
}
if (auto DTST = TL.getAs<DeducedTemplateSpecializationTypeLoc>()) {
TemplateName Name = DTST.getTypePtr()->getTemplateName();
if (SS.isSet())
Name = Context.getQualifiedTemplateName(SS.getScopeRep(),
/*HasTemplateKeyword*/ false,
Name.getAsTemplateDecl());
ParsedTemplateArgument Result(SS, TemplateTy::make(Name),
DTST.getTemplateNameLoc());
if (EllipsisLoc.isValid())
Result = Result.getTemplatePackExpansion(EllipsisLoc);
return Result;
}
}
// This is a normal type template argument. Note, if the type template
// argument is an injected-class-name for a template, it has a dual nature
// and can be used as either a type or a template. We handle that in
// convertTypeTemplateArgumentToTemplate.
return ParsedTemplateArgument(ParsedTemplateArgument::Type,
ParsedType.get().getAsOpaquePtr(),
TInfo->getTypeLoc().getBeginLoc());
}
/// ActOnTypeParameter - Called when a C++ template type parameter
/// (e.g., "typename T") has been parsed. Typename specifies whether
/// the keyword "typename" was used to declare the type parameter
/// (otherwise, "class" was used), and KeyLoc is the location of the
/// "class" or "typename" keyword. ParamName is the name of the
/// parameter (NULL indicates an unnamed template parameter) and
/// ParamNameLoc is the location of the parameter name (if any).
/// If the type parameter has a default argument, it will be added
/// later via ActOnTypeParameterDefault.
NamedDecl *Sema::ActOnTypeParameter(Scope *S, bool Typename,
SourceLocation EllipsisLoc,
SourceLocation KeyLoc,
IdentifierInfo *ParamName,
SourceLocation ParamNameLoc,
unsigned Depth, unsigned Position,
SourceLocation EqualLoc,
ParsedType DefaultArg,
bool HasTypeConstraint) {
assert(S->isTemplateParamScope() &&
"Template type parameter not in template parameter scope!");
bool IsParameterPack = EllipsisLoc.isValid();
TemplateTypeParmDecl *Param
= TemplateTypeParmDecl::Create(Context, Context.getTranslationUnitDecl(),
KeyLoc, ParamNameLoc, Depth, Position,
ParamName, Typename, IsParameterPack,
HasTypeConstraint);
Param->setAccess(AS_public);
if (Param->isParameterPack())
if (auto *LSI = getEnclosingLambda())
LSI->LocalPacks.push_back(Param);
if (ParamName) {
maybeDiagnoseTemplateParameterShadow(*this, S, ParamNameLoc, ParamName);
// Add the template parameter into the current scope.
S->AddDecl(Param);
IdResolver.AddDecl(Param);
}
// C++0x [temp.param]p9:
// A default template-argument may be specified for any kind of
// template-parameter that is not a template parameter pack.
if (DefaultArg && IsParameterPack) {
Diag(EqualLoc, diag::err_template_param_pack_default_arg);
DefaultArg = nullptr;
}
// Handle the default argument, if provided.
if (DefaultArg) {
TypeSourceInfo *DefaultTInfo;
GetTypeFromParser(DefaultArg, &DefaultTInfo);
assert(DefaultTInfo && "expected source information for type");
// Check for unexpanded parameter packs.
if (DiagnoseUnexpandedParameterPack(ParamNameLoc, DefaultTInfo,
UPPC_DefaultArgument))
return Param;
// Check the template argument itself.
if (CheckTemplateArgument(DefaultTInfo)) {
Param->setInvalidDecl();
return Param;
}
Param->setDefaultArgument(DefaultTInfo);
}
return Param;
}
/// Convert the parser's template argument list representation into our form.
static TemplateArgumentListInfo
makeTemplateArgumentListInfo(Sema &S, TemplateIdAnnotation &TemplateId) {
TemplateArgumentListInfo TemplateArgs(TemplateId.LAngleLoc,
TemplateId.RAngleLoc);
ASTTemplateArgsPtr TemplateArgsPtr(TemplateId.getTemplateArgs(),
TemplateId.NumArgs);
S.translateTemplateArguments(TemplateArgsPtr, TemplateArgs);
return TemplateArgs;
}
bool Sema::ActOnTypeConstraint(const CXXScopeSpec &SS,
TemplateIdAnnotation *TypeConstr,
TemplateTypeParmDecl *ConstrainedParameter,
SourceLocation EllipsisLoc) {
return BuildTypeConstraint(SS, TypeConstr, ConstrainedParameter, EllipsisLoc,
false);
}
bool Sema::BuildTypeConstraint(const CXXScopeSpec &SS,
TemplateIdAnnotation *TypeConstr,
TemplateTypeParmDecl *ConstrainedParameter,
SourceLocation EllipsisLoc,
bool AllowUnexpandedPack) {
TemplateName TN = TypeConstr->Template.get();
ConceptDecl *CD = cast<ConceptDecl>(TN.getAsTemplateDecl());
// C++2a [temp.param]p4:
// [...] The concept designated by a type-constraint shall be a type
// concept ([temp.concept]).
if (!CD->isTypeConcept()) {
Diag(TypeConstr->TemplateNameLoc,
diag::err_type_constraint_non_type_concept);
return true;
}
bool WereArgsSpecified = TypeConstr->LAngleLoc.isValid();
if (!WereArgsSpecified &&
CD->getTemplateParameters()->getMinRequiredArguments() > 1) {
Diag(TypeConstr->TemplateNameLoc,
diag::err_type_constraint_missing_arguments) << CD;
return true;
}
DeclarationNameInfo ConceptName(DeclarationName(TypeConstr->Name),
TypeConstr->TemplateNameLoc);
TemplateArgumentListInfo TemplateArgs;
if (TypeConstr->LAngleLoc.isValid()) {
TemplateArgs =
makeTemplateArgumentListInfo(*this, *TypeConstr);
if (EllipsisLoc.isInvalid() && !AllowUnexpandedPack) {
for (TemplateArgumentLoc Arg : TemplateArgs.arguments()) {
if (DiagnoseUnexpandedParameterPack(Arg, UPPC_TypeConstraint))
return true;
}
}
}
return AttachTypeConstraint(
SS.isSet() ? SS.getWithLocInContext(Context) : NestedNameSpecifierLoc(),
ConceptName, CD,
TypeConstr->LAngleLoc.isValid() ? &TemplateArgs : nullptr,
ConstrainedParameter, EllipsisLoc);
}
template<typename ArgumentLocAppender>
static ExprResult formImmediatelyDeclaredConstraint(
Sema &S, NestedNameSpecifierLoc NS, DeclarationNameInfo NameInfo,
ConceptDecl *NamedConcept, SourceLocation LAngleLoc,
SourceLocation RAngleLoc, QualType ConstrainedType,
SourceLocation ParamNameLoc, ArgumentLocAppender Appender,
SourceLocation EllipsisLoc) {
TemplateArgumentListInfo ConstraintArgs;
ConstraintArgs.addArgument(
S.getTrivialTemplateArgumentLoc(TemplateArgument(ConstrainedType),
/*NTTPType=*/QualType(), ParamNameLoc));
ConstraintArgs.setRAngleLoc(RAngleLoc);
ConstraintArgs.setLAngleLoc(LAngleLoc);
Appender(ConstraintArgs);
// C++2a [temp.param]p4:
// [...] This constraint-expression E is called the immediately-declared
// constraint of T. [...]
CXXScopeSpec SS;
SS.Adopt(NS);
ExprResult ImmediatelyDeclaredConstraint = S.CheckConceptTemplateId(
SS, /*TemplateKWLoc=*/SourceLocation(), NameInfo,
/*FoundDecl=*/NamedConcept, NamedConcept, &ConstraintArgs);
if (ImmediatelyDeclaredConstraint.isInvalid() || !EllipsisLoc.isValid())
return ImmediatelyDeclaredConstraint;
// C++2a [temp.param]p4:
// [...] If T is not a pack, then E is E', otherwise E is (E' && ...).
//
// We have the following case:
//
// template<typename T> concept C1 = true;
// template<C1... T> struct s1;
//
// The constraint: (C1<T> && ...)
//
// Note that the type of C1<T> is known to be 'bool', so we don't need to do
// any unqualified lookups for 'operator&&' here.
return S.BuildCXXFoldExpr(/*UnqualifiedLookup=*/nullptr,
/*LParenLoc=*/SourceLocation(),
ImmediatelyDeclaredConstraint.get(), BO_LAnd,
EllipsisLoc, /*RHS=*/nullptr,
/*RParenLoc=*/SourceLocation(),
/*NumExpansions=*/None);
}
/// Attach a type-constraint to a template parameter.
/// \returns true if an error occurred. This can happen if the
/// immediately-declared constraint could not be formed (e.g. incorrect number
/// of arguments for the named concept).
bool Sema::AttachTypeConstraint(NestedNameSpecifierLoc NS,
DeclarationNameInfo NameInfo,
ConceptDecl *NamedConcept,
const TemplateArgumentListInfo *TemplateArgs,
TemplateTypeParmDecl *ConstrainedParameter,
SourceLocation EllipsisLoc) {
// C++2a [temp.param]p4:
// [...] If Q is of the form C<A1, ..., An>, then let E' be
// C<T, A1, ..., An>. Otherwise, let E' be C<T>. [...]
const ASTTemplateArgumentListInfo *ArgsAsWritten =
TemplateArgs ? ASTTemplateArgumentListInfo::Create(Context,
*TemplateArgs) : nullptr;
QualType ParamAsArgument(ConstrainedParameter->getTypeForDecl(), 0);
ExprResult ImmediatelyDeclaredConstraint =
formImmediatelyDeclaredConstraint(
*this, NS, NameInfo, NamedConcept,
TemplateArgs ? TemplateArgs->getLAngleLoc() : SourceLocation(),
TemplateArgs ? TemplateArgs->getRAngleLoc() : SourceLocation(),
ParamAsArgument, ConstrainedParameter->getLocation(),
[&] (TemplateArgumentListInfo &ConstraintArgs) {
if (TemplateArgs)
for (const auto &ArgLoc : TemplateArgs->arguments())
ConstraintArgs.addArgument(ArgLoc);
}, EllipsisLoc);
if (ImmediatelyDeclaredConstraint.isInvalid())
return true;
ConstrainedParameter->setTypeConstraint(NS, NameInfo,
/*FoundDecl=*/NamedConcept,
NamedConcept, ArgsAsWritten,
ImmediatelyDeclaredConstraint.get());
return false;
}
bool Sema::AttachTypeConstraint(AutoTypeLoc TL, NonTypeTemplateParmDecl *NTTP,
SourceLocation EllipsisLoc) {
if (NTTP->getType() != TL.getType() ||
TL.getAutoKeyword() != AutoTypeKeyword::Auto) {
Diag(NTTP->getTypeSourceInfo()->getTypeLoc().getBeginLoc(),
diag::err_unsupported_placeholder_constraint)
<< NTTP->getTypeSourceInfo()->getTypeLoc().getSourceRange();
return true;
}
// FIXME: Concepts: This should be the type of the placeholder, but this is
// unclear in the wording right now.
DeclRefExpr *Ref =
BuildDeclRefExpr(NTTP, NTTP->getType(), VK_PRValue, NTTP->getLocation());
if (!Ref)
return true;
ExprResult ImmediatelyDeclaredConstraint = formImmediatelyDeclaredConstraint(
*this, TL.getNestedNameSpecifierLoc(), TL.getConceptNameInfo(),
TL.getNamedConcept(), TL.getLAngleLoc(), TL.getRAngleLoc(),
BuildDecltypeType(Ref), NTTP->getLocation(),
[&](TemplateArgumentListInfo &ConstraintArgs) {
for (unsigned I = 0, C = TL.getNumArgs(); I != C; ++I)
ConstraintArgs.addArgument(TL.getArgLoc(I));
},
EllipsisLoc);
if (ImmediatelyDeclaredConstraint.isInvalid() ||
!ImmediatelyDeclaredConstraint.isUsable())
return true;
NTTP->setPlaceholderTypeConstraint(ImmediatelyDeclaredConstraint.get());
return false;
}
/// Check that the type of a non-type template parameter is
/// well-formed.
///
/// \returns the (possibly-promoted) parameter type if valid;
/// otherwise, produces a diagnostic and returns a NULL type.
QualType Sema::CheckNonTypeTemplateParameterType(TypeSourceInfo *&TSI,
SourceLocation Loc) {
if (TSI->getType()->isUndeducedType()) {
// C++17 [temp.dep.expr]p3:
// An id-expression is type-dependent if it contains
// - an identifier associated by name lookup with a non-type
// template-parameter declared with a type that contains a
// placeholder type (7.1.7.4),
TSI = SubstAutoTypeSourceInfoDependent(TSI);
}
return CheckNonTypeTemplateParameterType(TSI->getType(), Loc);
}
/// Require the given type to be a structural type, and diagnose if it is not.
///
/// \return \c true if an error was produced.
bool Sema::RequireStructuralType(QualType T, SourceLocation Loc) {
if (T->isDependentType())
return false;
if (RequireCompleteType(Loc, T, diag::err_template_nontype_parm_incomplete))
return true;
if (T->isStructuralType())
return false;
// Structural types are required to be object types or lvalue references.
if (T->isRValueReferenceType()) {
Diag(Loc, diag::err_template_nontype_parm_rvalue_ref) << T;
return true;
}
// Don't mention structural types in our diagnostic prior to C++20. Also,
// there's not much more we can say about non-scalar non-class types --
// because we can't see functions or arrays here, those can only be language
// extensions.
if (!getLangOpts().CPlusPlus20 ||
(!T->isScalarType() && !T->isRecordType())) {
Diag(Loc, diag::err_template_nontype_parm_bad_type) << T;
return true;
}
// Structural types are required to be literal types.
if (RequireLiteralType(Loc, T, diag::err_template_nontype_parm_not_literal))
return true;
Diag(Loc, diag::err_template_nontype_parm_not_structural) << T;
// Drill down into the reason why the class is non-structural.
while (const CXXRecordDecl *RD = T->getAsCXXRecordDecl()) {
// All members are required to be public and non-mutable, and can't be of
// rvalue reference type. Check these conditions first to prefer a "local"
// reason over a more distant one.
for (const FieldDecl *FD : RD->fields()) {
if (FD->getAccess() != AS_public) {
Diag(FD->getLocation(), diag::note_not_structural_non_public) << T << 0;
return true;
}
if (FD->isMutable()) {
Diag(FD->getLocation(), diag::note_not_structural_mutable_field) << T;
return true;
}
if (FD->getType()->isRValueReferenceType()) {
Diag(FD->getLocation(), diag::note_not_structural_rvalue_ref_field)
<< T;
return true;
}
}
// All bases are required to be public.
for (const auto &BaseSpec : RD->bases()) {
if (BaseSpec.getAccessSpecifier() != AS_public) {
Diag(BaseSpec.getBaseTypeLoc(), diag::note_not_structural_non_public)
<< T << 1;
return true;
}
}
// All subobjects are required to be of structural types.
SourceLocation SubLoc;
QualType SubType;
int Kind = -1;
for (const FieldDecl *FD : RD->fields()) {
QualType T = Context.getBaseElementType(FD->getType());
if (!T->isStructuralType()) {
SubLoc = FD->getLocation();
SubType = T;
Kind = 0;
break;
}
}
if (Kind == -1) {
for (const auto &BaseSpec : RD->bases()) {
QualType T = BaseSpec.getType();
if (!T->isStructuralType()) {
SubLoc = BaseSpec.getBaseTypeLoc();
SubType = T;
Kind = 1;
break;
}
}
}
assert(Kind != -1 && "couldn't find reason why type is not structural");
Diag(SubLoc, diag::note_not_structural_subobject)
<< T << Kind << SubType;
T = SubType;
RD = T->getAsCXXRecordDecl();
}
return true;
}
QualType Sema::CheckNonTypeTemplateParameterType(QualType T,
SourceLocation Loc) {
// We don't allow variably-modified types as the type of non-type template
// parameters.
if (T->isVariablyModifiedType()) {
Diag(Loc, diag::err_variably_modified_nontype_template_param)
<< T;
return QualType();
}
// C++ [temp.param]p4:
//
// A non-type template-parameter shall have one of the following
// (optionally cv-qualified) types:
//
// -- integral or enumeration type,
if (T->isIntegralOrEnumerationType() ||
// -- pointer to object or pointer to function,
T->isPointerType() ||
// -- lvalue reference to object or lvalue reference to function,
T->isLValueReferenceType() ||
// -- pointer to member,
T->isMemberPointerType() ||
// -- std::nullptr_t, or
T->isNullPtrType() ||
// -- a type that contains a placeholder type.
T->isUndeducedType()) {
// C++ [temp.param]p5: The top-level cv-qualifiers on the template-parameter
// are ignored when determining its type.
return T.getUnqualifiedType();
}
// C++ [temp.param]p8:
//
// A non-type template-parameter of type "array of T" or
// "function returning T" is adjusted to be of type "pointer to
// T" or "pointer to function returning T", respectively.
if (T->isArrayType() || T->isFunctionType())
return Context.getDecayedType(T);
// If T is a dependent type, we can't do the check now, so we
// assume that it is well-formed. Note that stripping off the
// qualifiers here is not really correct if T turns out to be
// an array type, but we'll recompute the type everywhere it's
// used during instantiation, so that should be OK. (Using the
// qualified type is equally wrong.)
if (T->isDependentType())
return T.getUnqualifiedType();
// C++20 [temp.param]p6:
// -- a structural type
if (RequireStructuralType(T, Loc))
return QualType();
if (!getLangOpts().CPlusPlus20) {
// FIXME: Consider allowing structural types as an extension in C++17. (In
// earlier language modes, the template argument evaluation rules are too
// inflexible.)
Diag(Loc, diag::err_template_nontype_parm_bad_structural_type) << T;
return QualType();
}
Diag(Loc, diag::warn_cxx17_compat_template_nontype_parm_type) << T;
return T.getUnqualifiedType();
}
NamedDecl *Sema::ActOnNonTypeTemplateParameter(Scope *S, Declarator &D,
unsigned Depth,
unsigned Position,
SourceLocation EqualLoc,
Expr *Default) {
TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
// Check that we have valid decl-specifiers specified.
auto CheckValidDeclSpecifiers = [this, &D] {
// C++ [temp.param]
// p1
// template-parameter:
// ...
// parameter-declaration
// p2
// ... A storage class shall not be specified in a template-parameter
// declaration.
// [dcl.typedef]p1:
// The typedef specifier [...] shall not be used in the decl-specifier-seq
// of a parameter-declaration
const DeclSpec &DS = D.getDeclSpec();
auto EmitDiag = [this](SourceLocation Loc) {
Diag(Loc, diag::err_invalid_decl_specifier_in_nontype_parm)
<< FixItHint::CreateRemoval(Loc);
};
if (DS.getStorageClassSpec() != DeclSpec::SCS_unspecified)
EmitDiag(DS.getStorageClassSpecLoc());
if (DS.getThreadStorageClassSpec() != TSCS_unspecified)
EmitDiag(DS.getThreadStorageClassSpecLoc());
// [dcl.inline]p1:
// The inline specifier can be applied only to the declaration or
// definition of a variable or function.
if (DS.isInlineSpecified())
EmitDiag(DS.getInlineSpecLoc());
// [dcl.constexpr]p1:
// The constexpr specifier shall be applied only to the definition of a
// variable or variable template or the declaration of a function or
// function template.
if (DS.hasConstexprSpecifier())
EmitDiag(DS.getConstexprSpecLoc());
// [dcl.fct.spec]p1:
// Function-specifiers can be used only in function declarations.
if (DS.isVirtualSpecified())
EmitDiag(DS.getVirtualSpecLoc());
if (DS.hasExplicitSpecifier())
EmitDiag(DS.getExplicitSpecLoc());
if (DS.isNoreturnSpecified())
EmitDiag(DS.getNoreturnSpecLoc());
};
CheckValidDeclSpecifiers();
if (TInfo->getType()->isUndeducedType()) {
Diag(D.getIdentifierLoc(),
diag::warn_cxx14_compat_template_nontype_parm_auto_type)
<< QualType(TInfo->getType()->getContainedAutoType(), 0);
}
assert(S->isTemplateParamScope() &&
"Non-type template parameter not in template parameter scope!");
bool Invalid = false;
QualType T = CheckNonTypeTemplateParameterType(TInfo, D.getIdentifierLoc());
if (T.isNull()) {
T = Context.IntTy; // Recover with an 'int' type.
Invalid = true;
}
CheckFunctionOrTemplateParamDeclarator(S, D);
IdentifierInfo *ParamName = D.getIdentifier();
bool IsParameterPack = D.hasEllipsis();
NonTypeTemplateParmDecl *Param = NonTypeTemplateParmDecl::Create(
Context, Context.getTranslationUnitDecl(), D.getBeginLoc(),
D.getIdentifierLoc(), Depth, Position, ParamName, T, IsParameterPack,
TInfo);
Param->setAccess(AS_public);
if (AutoTypeLoc TL = TInfo->getTypeLoc().getContainedAutoTypeLoc())
if (TL.isConstrained())
if (AttachTypeConstraint(TL, Param, D.getEllipsisLoc()))
Invalid = true;
if (Invalid)
Param->setInvalidDecl();
if (Param->isParameterPack())
if (auto *LSI = getEnclosingLambda())
LSI->LocalPacks.push_back(Param);
if (ParamName) {
maybeDiagnoseTemplateParameterShadow(*this, S, D.getIdentifierLoc(),
ParamName);
// Add the template parameter into the current scope.
S->AddDecl(Param);
IdResolver.AddDecl(Param);
}
// C++0x [temp.param]p9:
// A default template-argument may be specified for any kind of
// template-parameter that is not a template parameter pack.
if (Default && IsParameterPack) {
Diag(EqualLoc, diag::err_template_param_pack_default_arg);
Default = nullptr;
}
// Check the well-formedness of the default template argument, if provided.
if (Default) {
// Check for unexpanded parameter packs.
if (DiagnoseUnexpandedParameterPack(Default, UPPC_DefaultArgument))
return Param;
TemplateArgument Converted;
ExprResult DefaultRes =
CheckTemplateArgument(Param, Param->getType(), Default, Converted);
if (DefaultRes.isInvalid()) {
Param->setInvalidDecl();
return Param;
}
Default = DefaultRes.get();
Param->setDefaultArgument(Default);
}
return Param;
}
/// ActOnTemplateTemplateParameter - Called when a C++ template template
/// parameter (e.g. T in template <template \<typename> class T> class array)
/// has been parsed. S is the current scope.
NamedDecl *Sema::ActOnTemplateTemplateParameter(Scope* S,
SourceLocation TmpLoc,
TemplateParameterList *Params,
SourceLocation EllipsisLoc,
IdentifierInfo *Name,
SourceLocation NameLoc,
unsigned Depth,
unsigned Position,
SourceLocation EqualLoc,
ParsedTemplateArgument Default) {
assert(S->isTemplateParamScope() &&
"Template template parameter not in template parameter scope!");
// Construct the parameter object.
bool IsParameterPack = EllipsisLoc.isValid();
TemplateTemplateParmDecl *Param =
TemplateTemplateParmDecl::Create(Context, Context.getTranslationUnitDecl(),
NameLoc.isInvalid()? TmpLoc : NameLoc,
Depth, Position, IsParameterPack,
Name, Params);
Param->setAccess(AS_public);
if (Param->isParameterPack())
if (auto *LSI = getEnclosingLambda())
LSI->LocalPacks.push_back(Param);
// If the template template parameter has a name, then link the identifier
// into the scope and lookup mechanisms.
if (Name) {
maybeDiagnoseTemplateParameterShadow(*this, S, NameLoc, Name);
S->AddDecl(Param);
IdResolver.AddDecl(Param);
}
if (Params->size() == 0) {
Diag(Param->getLocation(), diag::err_template_template_parm_no_parms)
<< SourceRange(Params->getLAngleLoc(), Params->getRAngleLoc());
Param->setInvalidDecl();
}
// C++0x [temp.param]p9:
// A default template-argument may be specified for any kind of
// template-parameter that is not a template parameter pack.
if (IsParameterPack && !Default.isInvalid()) {
Diag(EqualLoc, diag::err_template_param_pack_default_arg);
Default = ParsedTemplateArgument();
}
if (!Default.isInvalid()) {
// Check only that we have a template template argument. We don't want to
// try to check well-formedness now, because our template template parameter
// might have dependent types in its template parameters, which we wouldn't
// be able to match now.
//
// If none of the template template parameter's template arguments mention
// other template parameters, we could actually perform more checking here.
// However, it isn't worth doing.
TemplateArgumentLoc DefaultArg = translateTemplateArgument(*this, Default);
if (DefaultArg.getArgument().getAsTemplate().isNull()) {
Diag(DefaultArg.getLocation(), diag::err_template_arg_not_valid_template)
<< DefaultArg.getSourceRange();
return Param;
}
// Check for unexpanded parameter packs.
if (DiagnoseUnexpandedParameterPack(DefaultArg.getLocation(),
DefaultArg.getArgument().getAsTemplate(),
UPPC_DefaultArgument))
return Param;
Param->setDefaultArgument(Context, DefaultArg);
}
return Param;
}
/// ActOnTemplateParameterList - Builds a TemplateParameterList, optionally
/// constrained by RequiresClause, that contains the template parameters in
/// Params.
TemplateParameterList *
Sema::ActOnTemplateParameterList(unsigned Depth,
SourceLocation ExportLoc,
SourceLocation TemplateLoc,
SourceLocation LAngleLoc,
ArrayRef<NamedDecl *> Params,
SourceLocation RAngleLoc,
Expr *RequiresClause) {
if (ExportLoc.isValid())
Diag(ExportLoc, diag::warn_template_export_unsupported);
for (NamedDecl *P : Params)
warnOnReservedIdentifier(P);
return TemplateParameterList::Create(
Context, TemplateLoc, LAngleLoc,
llvm::makeArrayRef(Params.data(), Params.size()),
RAngleLoc, RequiresClause);
}
static void SetNestedNameSpecifier(Sema &S, TagDecl *T,
const CXXScopeSpec &SS) {
if (SS.isSet())
T->setQualifierInfo(SS.getWithLocInContext(S.Context));
}
DeclResult Sema::CheckClassTemplate(
Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
CXXScopeSpec &SS, IdentifierInfo *Name, SourceLocation NameLoc,
const ParsedAttributesView &Attr, TemplateParameterList *TemplateParams,
AccessSpecifier AS, SourceLocation ModulePrivateLoc,
SourceLocation FriendLoc, unsigned NumOuterTemplateParamLists,
TemplateParameterList **OuterTemplateParamLists, SkipBodyInfo *SkipBody) {
assert(TemplateParams && TemplateParams->size() > 0 &&
"No template parameters");
assert(TUK != TUK_Reference && "Can only declare or define class templates");
bool Invalid = false;
// Check that we can declare a template here.
if (CheckTemplateDeclScope(S, TemplateParams))
return true;
TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
assert(Kind != TTK_Enum && "can't build template of enumerated type");
// There is no such thing as an unnamed class template.
if (!Name) {
Diag(KWLoc, diag::err_template_unnamed_class);
return true;
}
// Find any previous declaration with this name. For a friend with no
// scope explicitly specified, we only look for tag declarations (per
// C++11 [basic.lookup.elab]p2).
DeclContext *SemanticContext;
LookupResult Previous(*this, Name, NameLoc,
(SS.isEmpty() && TUK == TUK_Friend)
? LookupTagName : LookupOrdinaryName,
forRedeclarationInCurContext());
if (SS.isNotEmpty() && !SS.isInvalid()) {
SemanticContext = computeDeclContext(SS, true);
if (!SemanticContext) {
// FIXME: Horrible, horrible hack! We can't currently represent this
// in the AST, and historically we have just ignored such friend
// class templates, so don't complain here.
Diag(NameLoc, TUK == TUK_Friend
? diag::warn_template_qualified_friend_ignored
: diag::err_template_qualified_declarator_no_match)
<< SS.getScopeRep() << SS.getRange();
return TUK != TUK_Friend;
}
if (RequireCompleteDeclContext(SS, SemanticContext))
return true;
// If we're adding a template to a dependent context, we may need to
// rebuilding some of the types used within the template parameter list,
// now that we know what the current instantiation is.
if (SemanticContext->isDependentContext()) {
ContextRAII SavedContext(*this, SemanticContext);
if (RebuildTemplateParamsInCurrentInstantiation(TemplateParams))
Invalid = true;
} else if (TUK != TUK_Friend && TUK != TUK_Reference)
diagnoseQualifiedDeclaration(SS, SemanticContext, Name, NameLoc, false);
LookupQualifiedName(Previous, SemanticContext);
} else {
SemanticContext = CurContext;
// C++14 [class.mem]p14:
// If T is the name of a class, then each of the following shall have a
// name different from T:
// -- every member template of class T
if (TUK != TUK_Friend &&
DiagnoseClassNameShadow(SemanticContext,
DeclarationNameInfo(Name, NameLoc)))
return true;
LookupName(Previous, S);
}
if (Previous.isAmbiguous())
return true;
NamedDecl *PrevDecl = nullptr;
if (Previous.begin() != Previous.end())
PrevDecl = (*Previous.begin())->getUnderlyingDecl();
if (PrevDecl && PrevDecl->isTemplateParameter()) {
// Maybe we will complain about the shadowed template parameter.
DiagnoseTemplateParameterShadow(NameLoc, PrevDecl);
// Just pretend that we didn't see the previous declaration.
PrevDecl = nullptr;
}
// If there is a previous declaration with the same name, check
// whether this is a valid redeclaration.
ClassTemplateDecl *PrevClassTemplate =
dyn_cast_or_null<ClassTemplateDecl>(PrevDecl);
// We may have found the injected-class-name of a class template,
// class template partial specialization, or class template specialization.
// In these cases, grab the template that is being defined or specialized.
if (!PrevClassTemplate && PrevDecl && isa<CXXRecordDecl>(PrevDecl) &&
cast<CXXRecordDecl>(PrevDecl)->isInjectedClassName()) {
PrevDecl = cast<CXXRecordDecl>(PrevDecl->getDeclContext());
PrevClassTemplate
= cast<CXXRecordDecl>(PrevDecl)->getDescribedClassTemplate();
if (!PrevClassTemplate && isa<ClassTemplateSpecializationDecl>(PrevDecl)) {
PrevClassTemplate
= cast<ClassTemplateSpecializationDecl>(PrevDecl)
->getSpecializedTemplate();
}
}
if (TUK == TUK_Friend) {
// C++ [namespace.memdef]p3:
// [...] When looking for a prior declaration of a class or a function
// declared as a friend, and when the name of the friend class or
// function is neither a qualified name nor a template-id, scopes outside
// the innermost enclosing namespace scope are not considered.
if (!SS.isSet()) {
DeclContext *OutermostContext = CurContext;
while (!OutermostContext->isFileContext())
OutermostContext = OutermostContext->getLookupParent();
if (PrevDecl &&
(OutermostContext->Equals(PrevDecl->getDeclContext()) ||
OutermostContext->Encloses(PrevDecl->getDeclContext()))) {
SemanticContext = PrevDecl->getDeclContext();
} else {
// Declarations in outer scopes don't matter. However, the outermost
// context we computed is the semantic context for our new
// declaration.
PrevDecl = PrevClassTemplate = nullptr;
SemanticContext = OutermostContext;
// Check that the chosen semantic context doesn't already contain a
// declaration of this name as a non-tag type.
Previous.clear(LookupOrdinaryName);
DeclContext *LookupContext = SemanticContext;
while (LookupContext->isTransparentContext())
LookupContext = LookupContext->getLookupParent();
LookupQualifiedName(Previous, LookupContext);
if (Previous.isAmbiguous())
return true;
if (Previous.begin() != Previous.end())
PrevDecl = (*Previous.begin())->getUnderlyingDecl();
}
}
} else if (PrevDecl &&
!isDeclInScope(Previous.getRepresentativeDecl(), SemanticContext,
S, SS.isValid()))
PrevDecl = PrevClassTemplate = nullptr;
if (auto *Shadow = dyn_cast_or_null<UsingShadowDecl>(
PrevDecl ? Previous.getRepresentativeDecl() : nullptr)) {
if (SS.isEmpty() &&
!(PrevClassTemplate &&
PrevClassTemplate->getDeclContext()->getRedeclContext()->Equals(
SemanticContext->getRedeclContext()))) {
Diag(KWLoc, diag::err_using_decl_conflict_reverse);
Diag(Shadow->getTargetDecl()->getLocation(),
diag::note_using_decl_target);
Diag(Shadow->getIntroducer()->getLocation(), diag::note_using_decl) << 0;
// Recover by ignoring the old declaration.
PrevDecl = PrevClassTemplate = nullptr;
}
}
if (PrevClassTemplate) {
// Ensure that the template parameter lists are compatible. Skip this check
// for a friend in a dependent context: the template parameter list itself
// could be dependent.
if (!(TUK == TUK_Friend && CurContext->isDependentContext()) &&
!TemplateParameterListsAreEqual(TemplateParams,
PrevClassTemplate->getTemplateParameters(),
/*Complain=*/true,
TPL_TemplateMatch))
return true;
// C++ [temp.class]p4:
// In a redeclaration, partial specialization, explicit
// specialization or explicit instantiation of a class template,
// the class-key shall agree in kind with the original class
// template declaration (7.1.5.3).
RecordDecl *PrevRecordDecl = PrevClassTemplate->getTemplatedDecl();
if (!isAcceptableTagRedeclaration(PrevRecordDecl, Kind,
TUK == TUK_Definition, KWLoc, Name)) {
Diag(KWLoc, diag::err_use_with_wrong_tag)
<< Name
<< FixItHint::CreateReplacement(KWLoc, PrevRecordDecl->getKindName());
Diag(PrevRecordDecl->getLocation(), diag::note_previous_use);
Kind = PrevRecordDecl->getTagKind();
}
// Check for redefinition of this class template.
if (TUK == TUK_Definition) {
if (TagDecl *Def = PrevRecordDecl->getDefinition()) {
// If we have a prior definition that is not visible, treat this as
// simply making that previous definition visible.
NamedDecl *Hidden = nullptr;
if (SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
SkipBody->ShouldSkip = true;
SkipBody->Previous = Def;
auto *Tmpl = cast<CXXRecordDecl>(Hidden)->getDescribedClassTemplate();
assert(Tmpl && "original definition of a class template is not a "
"class template?");
makeMergedDefinitionVisible(Hidden);
makeMergedDefinitionVisible(Tmpl);
} else {
Diag(NameLoc, diag::err_redefinition) << Name;
Diag(Def->getLocation(), diag::note_previous_definition);
// FIXME: Would it make sense to try to "forget" the previous
// definition, as part of error recovery?
return true;
}
}
}
} else if (PrevDecl) {
// C++ [temp]p5:
// A class template shall not have the same name as any other
// template, class, function, object, enumeration, enumerator,
// namespace, or type in the same scope (3.3), except as specified
// in (14.5.4).
Diag(NameLoc, diag::err_redefinition_different_kind) << Name;
Diag(PrevDecl->getLocation(), diag::note_previous_definition);
return true;
}
// Check the template parameter list of this declaration, possibly
// merging in the template parameter list from the previous class
// template declaration. Skip this check for a friend in a dependent
// context, because the template parameter list might be dependent.
if (!(TUK == TUK_Friend && CurContext->isDependentContext()) &&
CheckTemplateParameterList(
TemplateParams,
PrevClassTemplate
? PrevClassTemplate->getMostRecentDecl()->getTemplateParameters()
: nullptr,
(SS.isSet() && SemanticContext && SemanticContext->isRecord() &&
SemanticContext->isDependentContext())
? TPC_ClassTemplateMember
: TUK == TUK_Friend ? TPC_FriendClassTemplate : TPC_ClassTemplate,
SkipBody))
Invalid = true;
if (SS.isSet()) {
// If the name of the template was qualified, we must be defining the
// template out-of-line.
if (!SS.isInvalid() && !Invalid && !PrevClassTemplate) {
Diag(NameLoc, TUK == TUK_Friend ? diag::err_friend_decl_does_not_match
: diag::err_member_decl_does_not_match)
<< Name << SemanticContext << /*IsDefinition*/true << SS.getRange();
Invalid = true;
}
}
// If this is a templated friend in a dependent context we should not put it
// on the redecl chain. In some cases, the templated friend can be the most
// recent declaration tricking the template instantiator to make substitutions
// there.
// FIXME: Figure out how to combine with shouldLinkDependentDeclWithPrevious
bool ShouldAddRedecl
= !(TUK == TUK_Friend && CurContext->isDependentContext());
CXXRecordDecl *NewClass =
CXXRecordDecl::Create(Context, Kind, SemanticContext, KWLoc, NameLoc, Name,
PrevClassTemplate && ShouldAddRedecl ?
PrevClassTemplate->getTemplatedDecl() : nullptr,
/*DelayTypeCreation=*/true);
SetNestedNameSpecifier(*this, NewClass, SS);
if (NumOuterTemplateParamLists > 0)
NewClass->setTemplateParameterListsInfo(
Context, llvm::makeArrayRef(OuterTemplateParamLists,
NumOuterTemplateParamLists));
// Add alignment attributes if necessary; these attributes are checked when
// the ASTContext lays out the structure.
if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
AddAlignmentAttributesForRecord(NewClass);
AddMsStructLayoutForRecord(NewClass);
}
ClassTemplateDecl *NewTemplate
= ClassTemplateDecl::Create(Context, SemanticContext, NameLoc,
DeclarationName(Name), TemplateParams,
NewClass);
if (ShouldAddRedecl)
NewTemplate->setPreviousDecl(PrevClassTemplate);
NewClass->setDescribedClassTemplate(NewTemplate);
if (ModulePrivateLoc.isValid())
NewTemplate->setModulePrivate();
// Build the type for the class template declaration now.
QualType T = NewTemplate->getInjectedClassNameSpecialization();
T = Context.getInjectedClassNameType(NewClass, T);
assert(T->isDependentType() && "Class template type is not dependent?");
(void)T;
// If we are providing an explicit specialization of a member that is a
// class template, make a note of that.
if (PrevClassTemplate &&
PrevClassTemplate->getInstantiatedFromMemberTemplate())
PrevClassTemplate->setMemberSpecialization();
// Set the access specifier.
if (!Invalid && TUK != TUK_Friend && NewTemplate->getDeclContext()->isRecord())
SetMemberAccessSpecifier(NewTemplate, PrevClassTemplate, AS);
// Set the lexical context of these templates
NewClass->setLexicalDeclContext(CurContext);
NewTemplate->setLexicalDeclContext(CurContext);
if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
NewClass->startDefinition();
ProcessDeclAttributeList(S, NewClass, Attr);
if (PrevClassTemplate)
mergeDeclAttributes(NewClass, PrevClassTemplate->getTemplatedDecl());
AddPushedVisibilityAttribute(NewClass);
inferGslOwnerPointerAttribute(NewClass);
if (TUK != TUK_Friend) {
// Per C++ [basic.scope.temp]p2, skip the template parameter scopes.
Scope *Outer = S;
while ((Outer->getFlags() & Scope::TemplateParamScope) != 0)
Outer = Outer->getParent();
PushOnScopeChains(NewTemplate, Outer);
} else {
if (PrevClassTemplate && PrevClassTemplate->getAccess() != AS_none) {
NewTemplate->setAccess(PrevClassTemplate->getAccess());
NewClass->setAccess(PrevClassTemplate->getAccess());
}
NewTemplate->setObjectOfFriendDecl();
// Friend templates are visible in fairly strange ways.
if (!CurContext->isDependentContext()) {
DeclContext *DC = SemanticContext->getRedeclContext();
DC->makeDeclVisibleInContext(NewTemplate);
if (Scope *EnclosingScope = getScopeForDeclContext(S, DC))
PushOnScopeChains(NewTemplate, EnclosingScope,
/* AddToContext = */ false);
}
FriendDecl *Friend = FriendDecl::Create(
Context, CurContext, NewClass->getLocation(), NewTemplate, FriendLoc);
Friend->setAccess(AS_public);
CurContext->addDecl(Friend);
}
if (PrevClassTemplate)
CheckRedeclarationInModule(NewTemplate, PrevClassTemplate);
if (Invalid) {
NewTemplate->setInvalidDecl();
NewClass->setInvalidDecl();
}
ActOnDocumentableDecl(NewTemplate);
if (SkipBody && SkipBody->ShouldSkip)
return SkipBody->Previous;
return NewTemplate;
}
namespace {
/// Tree transform to "extract" a transformed type from a class template's
/// constructor to a deduction guide.
class ExtractTypeForDeductionGuide
: public TreeTransform<ExtractTypeForDeductionGuide> {
llvm::SmallVectorImpl<TypedefNameDecl *> &MaterializedTypedefs;
public:
typedef TreeTransform<ExtractTypeForDeductionGuide> Base;
ExtractTypeForDeductionGuide(
Sema &SemaRef,
llvm::SmallVectorImpl<TypedefNameDecl *> &MaterializedTypedefs)
: Base(SemaRef), MaterializedTypedefs(MaterializedTypedefs) {}
TypeSourceInfo *transform(TypeSourceInfo *TSI) { return TransformType(TSI); }
QualType TransformTypedefType(TypeLocBuilder &TLB, TypedefTypeLoc TL) {
ASTContext &Context = SemaRef.getASTContext();
TypedefNameDecl *OrigDecl = TL.getTypedefNameDecl();
TypedefNameDecl *Decl = OrigDecl;
// Transform the underlying type of the typedef and clone the Decl only if
// the typedef has a dependent context.
if (OrigDecl->getDeclContext()->isDependentContext()) {
TypeLocBuilder InnerTLB;
QualType Transformed =
TransformType(InnerTLB, OrigDecl->getTypeSourceInfo()->getTypeLoc());
TypeSourceInfo *TSI = InnerTLB.getTypeSourceInfo(Context, Transformed);
if (isa<TypeAliasDecl>(OrigDecl))
Decl = TypeAliasDecl::Create(
Context, Context.getTranslationUnitDecl(), OrigDecl->getBeginLoc(),
OrigDecl->getLocation(), OrigDecl->getIdentifier(), TSI);
else {
assert(isa<TypedefDecl>(OrigDecl) && "Not a Type alias or typedef");
Decl = TypedefDecl::Create(
Context, Context.getTranslationUnitDecl(), OrigDecl->getBeginLoc(),
OrigDecl->getLocation(), OrigDecl->getIdentifier(), TSI);
}
MaterializedTypedefs.push_back(Decl);
}
QualType TDTy = Context.getTypedefType(Decl);
TypedefTypeLoc TypedefTL = TLB.push<TypedefTypeLoc>(TDTy);
TypedefTL.setNameLoc(TL.getNameLoc());
return TDTy;
}
};
/// Transform to convert portions of a constructor declaration into the
/// corresponding deduction guide, per C++1z [over.match.class.deduct]p1.
struct ConvertConstructorToDeductionGuideTransform {
ConvertConstructorToDeductionGuideTransform(Sema &S,
ClassTemplateDecl *Template)
: SemaRef(S), Template(Template) {}
Sema &SemaRef;
ClassTemplateDecl *Template;
DeclContext *DC = Template->getDeclContext();
CXXRecordDecl *Primary = Template->getTemplatedDecl();
DeclarationName DeductionGuideName =
SemaRef.Context.DeclarationNames.getCXXDeductionGuideName(Template);
QualType DeducedType = SemaRef.Context.getTypeDeclType(Primary);
// Index adjustment to apply to convert depth-1 template parameters into
// depth-0 template parameters.
unsigned Depth1IndexAdjustment = Template->getTemplateParameters()->size();
/// Transform a constructor declaration into a deduction guide.
NamedDecl *transformConstructor(FunctionTemplateDecl *FTD,
CXXConstructorDecl *CD) {
SmallVector<TemplateArgument, 16> SubstArgs;
LocalInstantiationScope Scope(SemaRef);
// C++ [over.match.class.deduct]p1:
// -- For each constructor of the class template designated by the
// template-name, a function template with the following properties:
// -- The template parameters are the template parameters of the class
// template followed by the template parameters (including default
// template arguments) of the constructor, if any.
TemplateParameterList *TemplateParams = Template->getTemplateParameters();
if (FTD) {
TemplateParameterList *InnerParams = FTD->getTemplateParameters();
SmallVector<NamedDecl *, 16> AllParams;
AllParams.reserve(TemplateParams->size() + InnerParams->size());
AllParams.insert(AllParams.begin(),
TemplateParams->begin(), TemplateParams->end());
SubstArgs.reserve(InnerParams->size());
// Later template parameters could refer to earlier ones, so build up
// a list of substituted template arguments as we go.
for (NamedDecl *Param : *InnerParams) {
MultiLevelTemplateArgumentList Args;
Args.setKind(TemplateSubstitutionKind::Rewrite);
Args.addOuterTemplateArguments(SubstArgs);
Args.addOuterRetainedLevel();
NamedDecl *NewParam = transformTemplateParameter(Param, Args);
if (!NewParam)
return nullptr;
AllParams.push_back(NewParam);
SubstArgs.push_back(SemaRef.Context.getCanonicalTemplateArgument(
SemaRef.Context.getInjectedTemplateArg(NewParam)));
}
// Substitute new template parameters into requires-clause if present.
Expr *RequiresClause = nullptr;
if (Expr *InnerRC = InnerParams->getRequiresClause()) {
MultiLevelTemplateArgumentList Args;
Args.setKind(TemplateSubstitutionKind::Rewrite);
Args.addOuterTemplateArguments(SubstArgs);
Args.addOuterRetainedLevel();
ExprResult E = SemaRef.SubstExpr(InnerRC, Args);
if (E.isInvalid())
return nullptr;
RequiresClause = E.getAs<Expr>();
}
TemplateParams = TemplateParameterList::Create(
SemaRef.Context, InnerParams->getTemplateLoc(),
InnerParams->getLAngleLoc(), AllParams, InnerParams->getRAngleLoc(),
RequiresClause);
}
// If we built a new template-parameter-list, track that we need to
// substitute references to the old parameters into references to the
// new ones.
MultiLevelTemplateArgumentList Args;
Args.setKind(TemplateSubstitutionKind::Rewrite);
if (FTD) {
Args.addOuterTemplateArguments(SubstArgs);
Args.addOuterRetainedLevel();
}
FunctionProtoTypeLoc FPTL = CD->getTypeSourceInfo()->getTypeLoc()
.getAsAdjusted<FunctionProtoTypeLoc>();
assert(FPTL && "no prototype for constructor declaration");
// Transform the type of the function, adjusting the return type and
// replacing references to the old parameters with references to the
// new ones.
TypeLocBuilder TLB;
SmallVector<ParmVarDecl*, 8> Params;
SmallVector<TypedefNameDecl *, 4> MaterializedTypedefs;
QualType NewType = transformFunctionProtoType(TLB, FPTL, Params, Args,
MaterializedTypedefs);
if (NewType.isNull())
return nullptr;
TypeSourceInfo *NewTInfo = TLB.getTypeSourceInfo(SemaRef.Context, NewType);
return buildDeductionGuide(TemplateParams, CD, CD->getExplicitSpecifier(),
NewTInfo, CD->getBeginLoc(), CD->getLocation(),
CD->getEndLoc(), MaterializedTypedefs);
}
/// Build a deduction guide with the specified parameter types.
NamedDecl *buildSimpleDeductionGuide(MutableArrayRef<QualType> ParamTypes) {
SourceLocation Loc = Template->getLocation();
// Build the requested type.
FunctionProtoType::ExtProtoInfo EPI;
EPI.HasTrailingReturn = true;
QualType Result = SemaRef.BuildFunctionType(DeducedType, ParamTypes, Loc,
DeductionGuideName, EPI);
TypeSourceInfo *TSI = SemaRef.Context.getTrivialTypeSourceInfo(Result, Loc);
FunctionProtoTypeLoc FPTL =
TSI->getTypeLoc().castAs<FunctionProtoTypeLoc>();
// Build the parameters, needed during deduction / substitution.
SmallVector<ParmVarDecl*, 4> Params;
for (auto T : ParamTypes) {
ParmVarDecl *NewParam = ParmVarDecl::Create(
SemaRef.Context, DC, Loc, Loc, nullptr, T,
SemaRef.Context.getTrivialTypeSourceInfo(T, Loc), SC_None, nullptr);
NewParam->setScopeInfo(0, Params.size());
FPTL.setParam(Params.size(), NewParam);
Params.push_back(NewParam);
}
return buildDeductionGuide(Template->getTemplateParameters(), nullptr,
ExplicitSpecifier(), TSI, Loc, Loc, Loc);
}
private:
/// Transform a constructor template parameter into a deduction guide template
/// parameter, rebuilding any internal references to earlier parameters and
/// renumbering as we go.
NamedDecl *transformTemplateParameter(NamedDecl *TemplateParam,
MultiLevelTemplateArgumentList &Args) {
if (auto *TTP = dyn_cast<TemplateTypeParmDecl>(TemplateParam)) {
// TemplateTypeParmDecl's index cannot be changed after creation, so
// substitute it directly.
auto *NewTTP = TemplateTypeParmDecl::Create(
SemaRef.Context, DC, TTP->getBeginLoc(), TTP->getLocation(),
/*Depth*/ 0, Depth1IndexAdjustment + TTP->getIndex(),
TTP->getIdentifier(), TTP->wasDeclaredWithTypename(),
TTP->isParameterPack(), TTP->hasTypeConstraint(),
TTP->isExpandedParameterPack() ?
llvm::Optional<unsigned>(TTP->getNumExpansionParameters()) : None);
if (const auto *TC = TTP->getTypeConstraint())
SemaRef.SubstTypeConstraint(NewTTP, TC, Args);
if (TTP->hasDefaultArgument()) {
TypeSourceInfo *InstantiatedDefaultArg =
SemaRef.SubstType(TTP->getDefaultArgumentInfo(), Args,
TTP->getDefaultArgumentLoc(), TTP->getDeclName());
if (InstantiatedDefaultArg)
NewTTP->setDefaultArgument(InstantiatedDefaultArg);
}
SemaRef.CurrentInstantiationScope->InstantiatedLocal(TemplateParam,
NewTTP);
return NewTTP;
}
if (auto *TTP = dyn_cast<TemplateTemplateParmDecl>(TemplateParam))
return transformTemplateParameterImpl(TTP, Args);
return transformTemplateParameterImpl(
cast<NonTypeTemplateParmDecl>(TemplateParam), Args);
}
template<typename TemplateParmDecl>
TemplateParmDecl *
transformTemplateParameterImpl(TemplateParmDecl *OldParam,
MultiLevelTemplateArgumentList &Args) {
// Ask the template instantiator to do the heavy lifting for us, then adjust
// the index of the parameter once it's done.
auto *NewParam =
cast<TemplateParmDecl>(SemaRef.SubstDecl(OldParam, DC, Args));
assert(NewParam->getDepth() == 0 && "unexpected template param depth");
NewParam->setPosition(NewParam->getPosition() + Depth1IndexAdjustment);
return NewParam;
}
QualType transformFunctionProtoType(
TypeLocBuilder &TLB, FunctionProtoTypeLoc TL,
SmallVectorImpl<ParmVarDecl *> &Params,
MultiLevelTemplateArgumentList &Args,
SmallVectorImpl<TypedefNameDecl *> &MaterializedTypedefs) {
SmallVector<QualType, 4> ParamTypes;
const FunctionProtoType *T = TL.getTypePtr();
// -- The types of the function parameters are those of the constructor.
for (auto *OldParam : TL.getParams()) {
ParmVarDecl *NewParam =
transformFunctionTypeParam(OldParam, Args, MaterializedTypedefs);
if (!NewParam)
return QualType();
ParamTypes.push_back(NewParam->getType());
Params.push_back(NewParam);
}
// -- The return type is the class template specialization designated by
// the template-name and template arguments corresponding to the
// template parameters obtained from the class template.
//
// We use the injected-class-name type of the primary template instead.
// This has the convenient property that it is different from any type that
// the user can write in a deduction-guide (because they cannot enter the
// context of the template), so implicit deduction guides can never collide
// with explicit ones.
QualType ReturnType = DeducedType;
TLB.pushTypeSpec(ReturnType).setNameLoc(Primary->getLocation());
// Resolving a wording defect, we also inherit the variadicness of the
// constructor.
FunctionProtoType::ExtProtoInfo EPI;
EPI.Variadic = T->isVariadic();
EPI.HasTrailingReturn = true;
QualType Result = SemaRef.BuildFunctionType(
ReturnType, ParamTypes, TL.getBeginLoc(), DeductionGuideName, EPI);
if (Result.isNull())
return QualType();
FunctionProtoTypeLoc NewTL = TLB.push<FunctionProtoTypeLoc>(Result);
NewTL.setLocalRangeBegin(TL.getLocalRangeBegin());
NewTL.setLParenLoc(TL.getLParenLoc());
NewTL.setRParenLoc(TL.getRParenLoc());
NewTL.setExceptionSpecRange(SourceRange());
NewTL.setLocalRangeEnd(TL.getLocalRangeEnd());
for (unsigned I = 0, E = NewTL.getNumParams(); I != E; ++I)
NewTL.setParam(I, Params[I]);
return Result;
}
ParmVarDecl *transformFunctionTypeParam(
ParmVarDecl *OldParam, MultiLevelTemplateArgumentList &Args,
llvm::SmallVectorImpl<TypedefNameDecl *> &MaterializedTypedefs) {
TypeSourceInfo *OldDI = OldParam->getTypeSourceInfo();
TypeSourceInfo *NewDI;
if (auto PackTL = OldDI->getTypeLoc().getAs<PackExpansionTypeLoc>()) {
// Expand out the one and only element in each inner pack.
Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, 0);
NewDI =
SemaRef.SubstType(PackTL.getPatternLoc(), Args,
OldParam->getLocation(), OldParam->getDeclName());
if (!NewDI) return nullptr;
NewDI =
SemaRef.CheckPackExpansion(NewDI, PackTL.getEllipsisLoc(),
PackTL.getTypePtr()->getNumExpansions());
} else
NewDI = SemaRef.SubstType(OldDI, Args, OldParam->getLocation(),
OldParam->getDeclName());
if (!NewDI)
return nullptr;
// Extract the type. This (for instance) replaces references to typedef
// members of the current instantiations with the definitions of those
// typedefs, avoiding triggering instantiation of the deduced type during
// deduction.
NewDI = ExtractTypeForDeductionGuide(SemaRef, MaterializedTypedefs)
.transform(NewDI);
// Resolving a wording defect, we also inherit default arguments from the
// constructor.
ExprResult NewDefArg;
if (OldParam->hasDefaultArg()) {
// We don't care what the value is (we won't use it); just create a
// placeholder to indicate there is a default argument.
QualType ParamTy = NewDI->getType();
NewDefArg = new (SemaRef.Context)
OpaqueValueExpr(OldParam->getDefaultArg()->getBeginLoc(),
ParamTy.getNonLValueExprType(SemaRef.Context),
ParamTy->isLValueReferenceType() ? VK_LValue
: ParamTy->isRValueReferenceType() ? VK_XValue
: VK_PRValue);
}
ParmVarDecl *NewParam = ParmVarDecl::Create(SemaRef.Context, DC,
OldParam->getInnerLocStart(),
OldParam->getLocation(),
OldParam->getIdentifier(),
NewDI->getType(),
NewDI,
OldParam->getStorageClass(),
NewDefArg.get());
NewParam->setScopeInfo(OldParam->getFunctionScopeDepth(),
OldParam->getFunctionScopeIndex());
SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldParam, NewParam);
return NewParam;
}
FunctionTemplateDecl *buildDeductionGuide(
TemplateParameterList *TemplateParams, CXXConstructorDecl *Ctor,
ExplicitSpecifier ES, TypeSourceInfo *TInfo, SourceLocation LocStart,
SourceLocation Loc, SourceLocation LocEnd,
llvm::ArrayRef<TypedefNameDecl *> MaterializedTypedefs = {}) {
DeclarationNameInfo Name(DeductionGuideName, Loc);
ArrayRef<ParmVarDecl *> Params =
TInfo->getTypeLoc().castAs<FunctionProtoTypeLoc>().getParams();
// Build the implicit deduction guide template.
auto *Guide =
CXXDeductionGuideDecl::Create(SemaRef.Context, DC, LocStart, ES, Name,
TInfo->getType(), TInfo, LocEnd, Ctor);
Guide->setImplicit();
Guide->setParams(Params);
for (auto *Param : Params)
Param->setDeclContext(Guide);
for (auto *TD : MaterializedTypedefs)
TD->setDeclContext(Guide);
auto *GuideTemplate = FunctionTemplateDecl::Create(
SemaRef.Context, DC, Loc, DeductionGuideName, TemplateParams, Guide);
GuideTemplate->setImplicit();
Guide->setDescribedFunctionTemplate(GuideTemplate);
if (isa<CXXRecordDecl>(DC)) {
Guide->setAccess(AS_public);
GuideTemplate->setAccess(AS_public);
}
DC->addDecl(GuideTemplate);
return GuideTemplate;
}
};
}
void Sema::DeclareImplicitDeductionGuides(TemplateDecl *Template,
SourceLocation Loc) {
if (CXXRecordDecl *DefRecord =
cast<CXXRecordDecl>(Template->getTemplatedDecl())->getDefinition()) {
TemplateDecl *DescribedTemplate = DefRecord->getDescribedClassTemplate();
Template = DescribedTemplate ? DescribedTemplate : Template;
}
DeclContext *DC = Template->getDeclContext();
if (DC->isDependentContext())
return;
ConvertConstructorToDeductionGuideTransform Transform(
*this, cast<ClassTemplateDecl>(Template));
if (!isCompleteType(Loc, Transform.DeducedType))
return;
// Check whether we've already declared deduction guides for this template.
// FIXME: Consider storing a flag on the template to indicate this.
auto Existing = DC->lookup(Transform.DeductionGuideName);
for (auto *D : Existing)
if (D->isImplicit())
return;
// In case we were expanding a pack when we attempted to declare deduction
// guides, turn off pack expansion for everything we're about to do.
ArgumentPackSubstitutionIndexRAII SubstIndex(*this, -1);
// Create a template instantiation record to track the "instantiation" of
// constructors into deduction guides.
// FIXME: Add a kind for this to give more meaningful diagnostics. But can
// this substitution process actually fail?
InstantiatingTemplate BuildingDeductionGuides(*this, Loc, Template);
if (BuildingDeductionGuides.isInvalid())
return;
// Convert declared constructors into deduction guide templates.
// FIXME: Skip constructors for which deduction must necessarily fail (those
// for which some class template parameter without a default argument never
// appears in a deduced context).
bool AddedAny = false;
for (NamedDecl *D : LookupConstructors(Transform.Primary)) {
D = D->getUnderlyingDecl();
if (D->isInvalidDecl() || D->isImplicit())
continue;
D = cast<NamedDecl>(D->getCanonicalDecl());
auto *FTD = dyn_cast<FunctionTemplateDecl>(D);
auto *CD =
dyn_cast_or_null<CXXConstructorDecl>(FTD ? FTD->getTemplatedDecl() : D);
// Class-scope explicit specializations (MS extension) do not result in
// deduction guides.
if (!CD || (!FTD && CD->isFunctionTemplateSpecialization()))
continue;
// Cannot make a deduction guide when unparsed arguments are present.
if (std::any_of(CD->param_begin(), CD->param_end(), [](ParmVarDecl *P) {
return !P || P->hasUnparsedDefaultArg();
}))
continue;
Transform.transformConstructor(FTD, CD);
AddedAny = true;
}
// C++17 [over.match.class.deduct]
// -- If C is not defined or does not declare any constructors, an
// additional function template derived as above from a hypothetical
// constructor C().
if (!AddedAny)
Transform.buildSimpleDeductionGuide(None);
// -- An additional function template derived as above from a hypothetical
// constructor C(C), called the copy deduction candidate.
cast<CXXDeductionGuideDecl>(
cast<FunctionTemplateDecl>(
Transform.buildSimpleDeductionGuide(Transform.DeducedType))
->getTemplatedDecl())
->setIsCopyDeductionCandidate();
}
/// Diagnose the presence of a default template argument on a
/// template parameter, which is ill-formed in certain contexts.
///
/// \returns true if the default template argument should be dropped.
static bool DiagnoseDefaultTemplateArgument(Sema &S,
Sema::TemplateParamListContext TPC,
SourceLocation ParamLoc,
SourceRange DefArgRange) {
switch (TPC) {
case Sema::TPC_ClassTemplate:
case Sema::TPC_VarTemplate:
case Sema::TPC_TypeAliasTemplate:
return false;
case Sema::TPC_FunctionTemplate:
case Sema::TPC_FriendFunctionTemplateDefinition:
// C++ [temp.param]p9:
// A default template-argument shall not be specified in a
// function template declaration or a function template
// definition [...]
// If a friend function template declaration specifies a default
// template-argument, that declaration shall be a definition and shall be
// the only declaration of the function template in the translation unit.
// (C++98/03 doesn't have this wording; see DR226).
S.Diag(ParamLoc, S.getLangOpts().CPlusPlus11 ?
diag::warn_cxx98_compat_template_parameter_default_in_function_template
: diag::ext_template_parameter_default_in_function_template)
<< DefArgRange;
return false;
case Sema::TPC_ClassTemplateMember:
// C++0x [temp.param]p9:
// A default template-argument shall not be specified in the
// template-parameter-lists of the definition of a member of a
// class template that appears outside of the member's class.
S.Diag(ParamLoc, diag::err_template_parameter_default_template_member)
<< DefArgRange;
return true;
case Sema::TPC_FriendClassTemplate:
case Sema::TPC_FriendFunctionTemplate:
// C++ [temp.param]p9:
// A default template-argument shall not be specified in a
// friend template declaration.
S.Diag(ParamLoc, diag::err_template_parameter_default_friend_template)
<< DefArgRange;
return true;
// FIXME: C++0x [temp.param]p9 allows default template-arguments
// for friend function templates if there is only a single
// declaration (and it is a definition). Strange!
}
llvm_unreachable("Invalid TemplateParamListContext!");
}
/// Check for unexpanded parameter packs within the template parameters
/// of a template template parameter, recursively.
static bool DiagnoseUnexpandedParameterPacks(Sema &S,
TemplateTemplateParmDecl *TTP) {
// A template template parameter which is a parameter pack is also a pack
// expansion.
if (TTP->isParameterPack())
return false;
TemplateParameterList *Params = TTP->getTemplateParameters();
for (unsigned I = 0, N = Params->size(); I != N; ++I) {
NamedDecl *P = Params->getParam(I);
if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(P)) {
if (!TTP->isParameterPack())
if (const TypeConstraint *TC = TTP->getTypeConstraint())
if (TC->hasExplicitTemplateArgs())
for (auto &ArgLoc : TC->getTemplateArgsAsWritten()->arguments())
if (S.DiagnoseUnexpandedParameterPack(ArgLoc,
Sema::UPPC_TypeConstraint))
return true;
continue;
}
if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(P)) {
if (!NTTP->isParameterPack() &&
S.DiagnoseUnexpandedParameterPack(NTTP->getLocation(),
NTTP->getTypeSourceInfo(),
Sema::UPPC_NonTypeTemplateParameterType))
return true;
continue;
}
if (TemplateTemplateParmDecl *InnerTTP
= dyn_cast<TemplateTemplateParmDecl>(P))
if (DiagnoseUnexpandedParameterPacks(S, InnerTTP))
return true;
}
return false;
}
/// Checks the validity of a template parameter list, possibly
/// considering the template parameter list from a previous
/// declaration.
///
/// If an "old" template parameter list is provided, it must be
/// equivalent (per TemplateParameterListsAreEqual) to the "new"
/// template parameter list.
///
/// \param NewParams Template parameter list for a new template
/// declaration. This template parameter list will be updated with any
/// default arguments that are carried through from the previous
/// template parameter list.
///
/// \param OldParams If provided, template parameter list from a
/// previous declaration of the same template. Default template
/// arguments will be merged from the old template parameter list to
/// the new template parameter list.
///
/// \param TPC Describes the context in which we are checking the given
/// template parameter list.
///
/// \param SkipBody If we might have already made a prior merged definition
/// of this template visible, the corresponding body-skipping information.
/// Default argument redefinition is not an error when skipping such a body,
/// because (under the ODR) we can assume the default arguments are the same
/// as the prior merged definition.
///
/// \returns true if an error occurred, false otherwise.
bool Sema::CheckTemplateParameterList(TemplateParameterList *NewParams,
TemplateParameterList *OldParams,
TemplateParamListContext TPC,
SkipBodyInfo *SkipBody) {
bool Invalid = false;
// C++ [temp.param]p10:
// The set of default template-arguments available for use with a
// template declaration or definition is obtained by merging the
// default arguments from the definition (if in scope) and all
// declarations in scope in the same way default function
// arguments are (8.3.6).
bool SawDefaultArgument = false;
SourceLocation PreviousDefaultArgLoc;
// Dummy initialization to avoid warnings.
TemplateParameterList::iterator OldParam = NewParams->end();
if (OldParams)
OldParam = OldParams->begin();
bool RemoveDefaultArguments = false;
for (TemplateParameterList::iterator NewParam = NewParams->begin(),
NewParamEnd = NewParams->end();
NewParam != NewParamEnd; ++NewParam) {
// Variables used to diagnose redundant default arguments
bool RedundantDefaultArg = false;
SourceLocation OldDefaultLoc;
SourceLocation NewDefaultLoc;
// Variable used to diagnose missing default arguments
bool MissingDefaultArg = false;
// Variable used to diagnose non-final parameter packs
bool SawParameterPack = false;
if (TemplateTypeParmDecl *NewTypeParm
= dyn_cast<TemplateTypeParmDecl>(*NewParam)) {
// Check the presence of a default argument here.
if (NewTypeParm->hasDefaultArgument() &&
DiagnoseDefaultTemplateArgument(*this, TPC,
NewTypeParm->getLocation(),
NewTypeParm->getDefaultArgumentInfo()->getTypeLoc()
.getSourceRange()))
NewTypeParm->removeDefaultArgument();
// Merge default arguments for template type parameters.
TemplateTypeParmDecl *OldTypeParm
= OldParams? cast<TemplateTypeParmDecl>(*OldParam) : nullptr;
if (NewTypeParm->isParameterPack()) {
assert(!NewTypeParm->hasDefaultArgument() &&
"Parameter packs can't have a default argument!");
SawParameterPack = true;
} else if (OldTypeParm && hasVisibleDefaultArgument(OldTypeParm) &&
NewTypeParm->hasDefaultArgument() &&
(!SkipBody || !SkipBody->ShouldSkip)) {
OldDefaultLoc = OldTypeParm->getDefaultArgumentLoc();
NewDefaultLoc = NewTypeParm->getDefaultArgumentLoc();
SawDefaultArgument = true;
RedundantDefaultArg = true;
PreviousDefaultArgLoc = NewDefaultLoc;
} else if (OldTypeParm && OldTypeParm->hasDefaultArgument()) {
// Merge the default argument from the old declaration to the
// new declaration.
NewTypeParm->setInheritedDefaultArgument(Context, OldTypeParm);
PreviousDefaultArgLoc = OldTypeParm->getDefaultArgumentLoc();
} else if (NewTypeParm->hasDefaultArgument()) {
SawDefaultArgument = true;
PreviousDefaultArgLoc = NewTypeParm->getDefaultArgumentLoc();
} else if (SawDefaultArgument)
MissingDefaultArg = true;
} else if (NonTypeTemplateParmDecl *NewNonTypeParm
= dyn_cast<NonTypeTemplateParmDecl>(*NewParam)) {
// Check for unexpanded parameter packs.
if (!NewNonTypeParm->isParameterPack() &&
DiagnoseUnexpandedParameterPack(NewNonTypeParm->getLocation(),
NewNonTypeParm->getTypeSourceInfo(),
UPPC_NonTypeTemplateParameterType)) {
Invalid = true;
continue;
}
// Check the presence of a default argument here.
if (NewNonTypeParm->hasDefaultArgument() &&
DiagnoseDefaultTemplateArgument(*this, TPC,
NewNonTypeParm->getLocation(),
NewNonTypeParm->getDefaultArgument()->getSourceRange())) {
NewNonTypeParm->removeDefaultArgument();
}
// Merge default arguments for non-type template parameters
NonTypeTemplateParmDecl *OldNonTypeParm
= OldParams? cast<NonTypeTemplateParmDecl>(*OldParam) : nullptr;
if (NewNonTypeParm->isParameterPack()) {
assert(!NewNonTypeParm->hasDefaultArgument() &&
"Parameter packs can't have a default argument!");
if (!NewNonTypeParm->isPackExpansion())
SawParameterPack = true;
} else if (OldNonTypeParm && hasVisibleDefaultArgument(OldNonTypeParm) &&
NewNonTypeParm->hasDefaultArgument() &&
(!SkipBody || !SkipBody->ShouldSkip)) {
OldDefaultLoc = OldNonTypeParm->getDefaultArgumentLoc();
NewDefaultLoc = NewNonTypeParm->getDefaultArgumentLoc();
SawDefaultArgument = true;
RedundantDefaultArg = true;
PreviousDefaultArgLoc = NewDefaultLoc;
} else if (OldNonTypeParm && OldNonTypeParm->hasDefaultArgument()) {
// Merge the default argument from the old declaration to the
// new declaration.
NewNonTypeParm->setInheritedDefaultArgument(Context, OldNonTypeParm);
PreviousDefaultArgLoc = OldNonTypeParm->getDefaultArgumentLoc();
} else if (NewNonTypeParm->hasDefaultArgument()) {
SawDefaultArgument = true;
PreviousDefaultArgLoc = NewNonTypeParm->getDefaultArgumentLoc();
} else if (SawDefaultArgument)
MissingDefaultArg = true;
} else {
TemplateTemplateParmDecl *NewTemplateParm
= cast<TemplateTemplateParmDecl>(*NewParam);
// Check for unexpanded parameter packs, recursively.
if (::DiagnoseUnexpandedParameterPacks(*this, NewTemplateParm)) {
Invalid = true;
continue;
}
// Check the presence of a default argument here.
if (NewTemplateParm->hasDefaultArgument() &&
DiagnoseDefaultTemplateArgument(*this, TPC,
NewTemplateParm->getLocation(),
NewTemplateParm->getDefaultArgument().getSourceRange()))
NewTemplateParm->removeDefaultArgument();
// Merge default arguments for template template parameters
TemplateTemplateParmDecl *OldTemplateParm
= OldParams? cast<TemplateTemplateParmDecl>(*OldParam) : nullptr;
if (NewTemplateParm->isParameterPack()) {
assert(!NewTemplateParm->hasDefaultArgument() &&
"Parameter packs can't have a default argument!");
if (!NewTemplateParm->isPackExpansion())
SawParameterPack = true;
} else if (OldTemplateParm &&
hasVisibleDefaultArgument(OldTemplateParm) &&
NewTemplateParm->hasDefaultArgument() &&
(!SkipBody || !SkipBody->ShouldSkip)) {
OldDefaultLoc = OldTemplateParm->getDefaultArgument().getLocation();
NewDefaultLoc = NewTemplateParm->getDefaultArgument().getLocation();
SawDefaultArgument = true;
RedundantDefaultArg = true;
PreviousDefaultArgLoc = NewDefaultLoc;
} else if (OldTemplateParm && OldTemplateParm->hasDefaultArgument()) {
// Merge the default argument from the old declaration to the
// new declaration.
NewTemplateParm->setInheritedDefaultArgument(Context, OldTemplateParm);
PreviousDefaultArgLoc
= OldTemplateParm->getDefaultArgument().getLocation();
} else if (NewTemplateParm->hasDefaultArgument()) {
SawDefaultArgument = true;
PreviousDefaultArgLoc
= NewTemplateParm->getDefaultArgument().getLocation();
} else if (SawDefaultArgument)
MissingDefaultArg = true;
}
// C++11 [temp.param]p11:
// If a template parameter of a primary class template or alias template
// is a template parameter pack, it shall be the last template parameter.
if (SawParameterPack && (NewParam + 1) != NewParamEnd &&
(TPC == TPC_ClassTemplate || TPC == TPC_VarTemplate ||
TPC == TPC_TypeAliasTemplate)) {
Diag((*NewParam)->getLocation(),
diag::err_template_param_pack_must_be_last_template_parameter);
Invalid = true;
}
if (RedundantDefaultArg) {
// C++ [temp.param]p12:
// A template-parameter shall not be given default arguments
// by two different declarations in the same scope.
Diag(NewDefaultLoc, diag::err_template_param_default_arg_redefinition);
Diag(OldDefaultLoc, diag::note_template_param_prev_default_arg);
Invalid = true;
} else if (MissingDefaultArg && TPC != TPC_FunctionTemplate) {
// C++ [temp.param]p11:
// If a template-parameter of a class template has a default
// template-argument, each subsequent template-parameter shall either
// have a default template-argument supplied or be a template parameter
// pack.
Diag((*NewParam)->getLocation(),
diag::err_template_param_default_arg_missing);
Diag(PreviousDefaultArgLoc, diag::note_template_param_prev_default_arg);
Invalid = true;
RemoveDefaultArguments = true;
}
// If we have an old template parameter list that we're merging
// in, move on to the next parameter.
if (OldParams)
++OldParam;
}
// We were missing some default arguments at the end of the list, so remove
// all of the default arguments.
if (RemoveDefaultArguments) {
for (TemplateParameterList::iterator NewParam = NewParams->begin(),
NewParamEnd = NewParams->end();
NewParam != NewParamEnd; ++NewParam) {
if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*NewParam))
TTP->removeDefaultArgument();
else if (NonTypeTemplateParmDecl *NTTP
= dyn_cast<NonTypeTemplateParmDecl>(*NewParam))
NTTP->removeDefaultArgument();
else
cast<TemplateTemplateParmDecl>(*NewParam)->removeDefaultArgument();
}
}
return Invalid;
}
namespace {
/// A class which looks for a use of a certain level of template
/// parameter.
struct DependencyChecker : RecursiveASTVisitor<DependencyChecker> {
typedef RecursiveASTVisitor<DependencyChecker> super;
unsigned Depth;
// Whether we're looking for a use of a template parameter that makes the
// overall construct type-dependent / a dependent type. This is strictly
// best-effort for now; we may fail to match at all for a dependent type
// in some cases if this is set.
bool IgnoreNonTypeDependent;
bool Match;
SourceLocation MatchLoc;
DependencyChecker(unsigned Depth, bool IgnoreNonTypeDependent)
: Depth(Depth), IgnoreNonTypeDependent(IgnoreNonTypeDependent),
Match(false) {}
DependencyChecker(TemplateParameterList *Params, bool IgnoreNonTypeDependent)
: IgnoreNonTypeDependent(IgnoreNonTypeDependent), Match(false) {
NamedDecl *ND = Params->getParam(0);
if (TemplateTypeParmDecl *PD = dyn_cast<TemplateTypeParmDecl>(ND)) {
Depth = PD->getDepth();
} else if (NonTypeTemplateParmDecl *PD =
dyn_cast<NonTypeTemplateParmDecl>(ND)) {
Depth = PD->getDepth();
} else {
Depth = cast<TemplateTemplateParmDecl>(ND)->getDepth();
}
}
bool Matches(unsigned ParmDepth, SourceLocation Loc = SourceLocation()) {
if (ParmDepth >= Depth) {
Match = true;
MatchLoc = Loc;
return true;
}
return false;
}
bool TraverseStmt(Stmt *S, DataRecursionQueue *Q = nullptr) {
// Prune out non-type-dependent expressions if requested. This can
// sometimes result in us failing to find a template parameter reference
// (if a value-dependent expression creates a dependent type), but this
// mode is best-effort only.
if (auto *E = dyn_cast_or_null<Expr>(S))
if (IgnoreNonTypeDependent && !E->isTypeDependent())
return true;
return super::TraverseStmt(S, Q);
}
bool TraverseTypeLoc(TypeLoc TL) {
if (IgnoreNonTypeDependent && !TL.isNull() &&
!TL.getType()->isDependentType())
return true;
return super::TraverseTypeLoc(TL);
}
bool VisitTemplateTypeParmTypeLoc(TemplateTypeParmTypeLoc TL) {
return !Matches(TL.getTypePtr()->getDepth(), TL.getNameLoc());
}
bool VisitTemplateTypeParmType(const TemplateTypeParmType *T) {
// For a best-effort search, keep looking until we find a location.
return IgnoreNonTypeDependent || !Matches(T->getDepth());
}
bool TraverseTemplateName(TemplateName N) {
if (TemplateTemplateParmDecl *PD =
dyn_cast_or_null<TemplateTemplateParmDecl>(N.getAsTemplateDecl()))
if (Matches(PD->getDepth()))
return false;
return super::TraverseTemplateName(N);
}
bool VisitDeclRefExpr(DeclRefExpr *E) {
if (NonTypeTemplateParmDecl *PD =
dyn_cast<NonTypeTemplateParmDecl>(E->getDecl()))
if (Matches(PD->getDepth(), E->getExprLoc()))
return false;
return super::VisitDeclRefExpr(E);
}
bool VisitSubstTemplateTypeParmType(const SubstTemplateTypeParmType *T) {
return TraverseType(T->getReplacementType());
}
bool
VisitSubstTemplateTypeParmPackType(const SubstTemplateTypeParmPackType *T) {
return TraverseTemplateArgument(T->getArgumentPack());
}
bool TraverseInjectedClassNameType(const InjectedClassNameType *T) {
return TraverseType(T->getInjectedSpecializationType());
}
};
} // end anonymous namespace
/// Determines whether a given type depends on the given parameter
/// list.
static bool
DependsOnTemplateParameters(QualType T, TemplateParameterList *Params) {
if (!Params->size())
return false;
DependencyChecker Checker(Params, /*IgnoreNonTypeDependent*/false);
Checker.TraverseType(T);
return Checker.Match;
}
// Find the source range corresponding to the named type in the given
// nested-name-specifier, if any.
static SourceRange getRangeOfTypeInNestedNameSpecifier(ASTContext &Context,
QualType T,
const CXXScopeSpec &SS) {
NestedNameSpecifierLoc NNSLoc(SS.getScopeRep(), SS.location_data());
while (NestedNameSpecifier *NNS = NNSLoc.getNestedNameSpecifier()) {
if (const Type *CurType = NNS->getAsType()) {
if (Context.hasSameUnqualifiedType(T, QualType(CurType, 0)))
return NNSLoc.getTypeLoc().getSourceRange();
} else
break;
NNSLoc = NNSLoc.getPrefix();
}
return SourceRange();
}
/// Match the given template parameter lists to the given scope
/// specifier, returning the template parameter list that applies to the
/// name.
///
/// \param DeclStartLoc the start of the declaration that has a scope
/// specifier or a template parameter list.
///
/// \param DeclLoc The location of the declaration itself.
///
/// \param SS the scope specifier that will be matched to the given template
/// parameter lists. This scope specifier precedes a qualified name that is
/// being declared.
///
/// \param TemplateId The template-id following the scope specifier, if there
/// is one. Used to check for a missing 'template<>'.
///
/// \param ParamLists the template parameter lists, from the outermost to the
/// innermost template parameter lists.
///
/// \param IsFriend Whether to apply the slightly different rules for
/// matching template parameters to scope specifiers in friend
/// declarations.
///
/// \param IsMemberSpecialization will be set true if the scope specifier
/// denotes a fully-specialized type, and therefore this is a declaration of
/// a member specialization.
///
/// \returns the template parameter list, if any, that corresponds to the
/// name that is preceded by the scope specifier @p SS. This template
/// parameter list may have template parameters (if we're declaring a
/// template) or may have no template parameters (if we're declaring a
/// template specialization), or may be NULL (if what we're declaring isn't
/// itself a template).
TemplateParameterList *Sema::MatchTemplateParametersToScopeSpecifier(
SourceLocation DeclStartLoc, SourceLocation DeclLoc, const CXXScopeSpec &SS,
TemplateIdAnnotation *TemplateId,
ArrayRef<TemplateParameterList *> ParamLists, bool IsFriend,
bool &IsMemberSpecialization, bool &Invalid, bool SuppressDiagnostic) {
IsMemberSpecialization = false;
Invalid = false;
// The sequence of nested types to which we will match up the template
// parameter lists. We first build this list by starting with the type named
// by the nested-name-specifier and walking out until we run out of types.
SmallVector<QualType, 4> NestedTypes;
QualType T;
if (SS.getScopeRep()) {
if (CXXRecordDecl *Record
= dyn_cast_or_null<CXXRecordDecl>(computeDeclContext(SS, true)))
T = Context.getTypeDeclType(Record);
else
T = QualType(SS.getScopeRep()->getAsType(), 0);
}
// If we found an explicit specialization that prevents us from needing
// 'template<>' headers, this will be set to the location of that
// explicit specialization.
SourceLocation ExplicitSpecLoc;
while (!T.isNull()) {
NestedTypes.push_back(T);
// Retrieve the parent of a record type.
if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) {
// If this type is an explicit specialization, we're done.
if (ClassTemplateSpecializationDecl *Spec
= dyn_cast<ClassTemplateSpecializationDecl>(Record)) {
if (!isa<ClassTemplatePartialSpecializationDecl>(Spec) &&
Spec->getSpecializationKind() == TSK_ExplicitSpecialization) {
ExplicitSpecLoc = Spec->getLocation();
break;
}
} else if (Record->getTemplateSpecializationKind()
== TSK_ExplicitSpecialization) {
ExplicitSpecLoc = Record->getLocation();
break;
}
if (TypeDecl *Parent = dyn_cast<TypeDecl>(Record->getParent()))
T = Context.getTypeDeclType(Parent);
else
T = QualType();
continue;
}
if (const TemplateSpecializationType *TST
= T->getAs<TemplateSpecializationType>()) {
if (TemplateDecl *Template = TST->getTemplateName().getAsTemplateDecl()) {
if (TypeDecl *Parent = dyn_cast<TypeDecl>(Template->getDeclContext()))
T = Context.getTypeDeclType(Parent);
else
T = QualType();
continue;
}
}
// Look one step prior in a dependent template specialization type.
if (const DependentTemplateSpecializationType *DependentTST
= T->getAs<DependentTemplateSpecializationType>()) {
if (NestedNameSpecifier *NNS = DependentTST->getQualifier())
T = QualType(NNS->getAsType(), 0);
else
T = QualType();
continue;
}
// Look one step prior in a dependent name type.
if (const DependentNameType *DependentName = T->getAs<DependentNameType>()){
if (NestedNameSpecifier *NNS = DependentName->getQualifier())
T = QualType(NNS->getAsType(), 0);
else
T = QualType();
continue;
}
// Retrieve the parent of an enumeration type.
if (const EnumType *EnumT = T->getAs<EnumType>()) {
// FIXME: Forward-declared enums require a TSK_ExplicitSpecialization
// check here.
EnumDecl *Enum = EnumT->getDecl();
// Get to the parent type.
if (TypeDecl *Parent = dyn_cast<TypeDecl>(Enum->getParent()))
T = Context.getTypeDeclType(Parent);
else
T = QualType();
continue;
}
T = QualType();
}
// Reverse the nested types list, since we want to traverse from the outermost
// to the innermost while checking template-parameter-lists.
std::reverse(NestedTypes.begin(), NestedTypes.end());
// C++0x [temp.expl.spec]p17:
// A member or a member template may be nested within many
// enclosing class templates. In an explicit specialization for
// such a member, the member declaration shall be preceded by a
// template<> for each enclosing class template that is
// explicitly specialized.
bool SawNonEmptyTemplateParameterList = false;
auto CheckExplicitSpecialization = [&](SourceRange Range, bool Recovery) {
if (SawNonEmptyTemplateParameterList) {
if (!SuppressDiagnostic)
Diag(DeclLoc, diag::err_specialize_member_of_template)
<< !Recovery << Range;
Invalid = true;
IsMemberSpecialization = false;
return true;
}
return false;
};
auto DiagnoseMissingExplicitSpecialization = [&] (SourceRange Range) {
// Check that we can have an explicit specialization here.
if (CheckExplicitSpecialization(Range, true))
return true;
// We don't have a template header, but we should.
SourceLocation ExpectedTemplateLoc;
if (!ParamLists.empty())
ExpectedTemplateLoc = ParamLists[0]->getTemplateLoc();
else
ExpectedTemplateLoc = DeclStartLoc;
if (!SuppressDiagnostic)
Diag(DeclLoc, diag::err_template_spec_needs_header)
<< Range
<< FixItHint::CreateInsertion(ExpectedTemplateLoc, "template<> ");
return false;
};
unsigned ParamIdx = 0;
for (unsigned TypeIdx = 0, NumTypes = NestedTypes.size(); TypeIdx != NumTypes;
++TypeIdx) {
T = NestedTypes[TypeIdx];
// Whether we expect a 'template<>' header.
bool NeedEmptyTemplateHeader = false;
// Whether we expect a template header with parameters.
bool NeedNonemptyTemplateHeader = false;
// For a dependent type, the set of template parameters that we
// expect to see.
TemplateParameterList *ExpectedTemplateParams = nullptr;
// C++0x [temp.expl.spec]p15:
// A member or a member template may be nested within many enclosing
// class templates. In an explicit specialization for such a member, the
// member declaration shall be preceded by a template<> for each
// enclosing class template that is explicitly specialized.
if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) {
if (ClassTemplatePartialSpecializationDecl *Partial
= dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
ExpectedTemplateParams = Partial->getTemplateParameters();
NeedNonemptyTemplateHeader = true;
} else if (Record->isDependentType()) {
if (Record->getDescribedClassTemplate()) {
ExpectedTemplateParams = Record->getDescribedClassTemplate()
->getTemplateParameters();
NeedNonemptyTemplateHeader = true;
}
} else if (ClassTemplateSpecializationDecl *Spec
= dyn_cast<ClassTemplateSpecializationDecl>(Record)) {
// C++0x [temp.expl.spec]p4:
// Members of an explicitly specialized class template are defined
// in the same manner as members of normal classes, and not using
// the template<> syntax.
if (Spec->getSpecializationKind() != TSK_ExplicitSpecialization)
NeedEmptyTemplateHeader = true;
else
continue;
} else if (Record->getTemplateSpecializationKind()) {
if (Record->getTemplateSpecializationKind()
!= TSK_ExplicitSpecialization &&
TypeIdx == NumTypes - 1)
IsMemberSpecialization = true;
continue;
}
} else if (const TemplateSpecializationType *TST
= T->getAs<TemplateSpecializationType>()) {
if (TemplateDecl *Template = TST->getTemplateName().getAsTemplateDecl()) {
ExpectedTemplateParams = Template->getTemplateParameters();
NeedNonemptyTemplateHeader = true;
}
} else if (T->getAs<DependentTemplateSpecializationType>()) {
// FIXME: We actually could/should check the template arguments here
// against the corresponding template parameter list.
NeedNonemptyTemplateHeader = false;
}
// C++ [temp.expl.spec]p16:
// In an explicit specialization declaration for a member of a class
// template or a member template that ap- pears in namespace scope, the
// member template and some of its enclosing class templates may remain
// unspecialized, except that the declaration shall not explicitly
// specialize a class member template if its en- closing class templates
// are not explicitly specialized as well.
if (ParamIdx < ParamLists.size()) {
if (ParamLists[ParamIdx]->size() == 0) {
if (CheckExplicitSpecialization(ParamLists[ParamIdx]->getSourceRange(),
false))
return nullptr;
} else
SawNonEmptyTemplateParameterList = true;
}
if (NeedEmptyTemplateHeader) {
// If we're on the last of the types, and we need a 'template<>' header
// here, then it's a member specialization.
if (TypeIdx == NumTypes - 1)
IsMemberSpecialization = true;
if (ParamIdx < ParamLists.size()) {
if (ParamLists[ParamIdx]->size() > 0) {
// The header has template parameters when it shouldn't. Complain.
if (!SuppressDiagnostic)
Diag(ParamLists[ParamIdx]->getTemplateLoc(),
diag::err_template_param_list_matches_nontemplate)
<< T
<< SourceRange(ParamLists[ParamIdx]->getLAngleLoc(),
ParamLists[ParamIdx]->getRAngleLoc())
<< getRangeOfTypeInNestedNameSpecifier(Context, T, SS);
Invalid = true;
return nullptr;
}
// Consume this template header.
++ParamIdx;
continue;
}
if (!IsFriend)
if (DiagnoseMissingExplicitSpecialization(
getRangeOfTypeInNestedNameSpecifier(Context, T, SS)))
return nullptr;
continue;
}
if (NeedNonemptyTemplateHeader) {
// In friend declarations we can have template-ids which don't
// depend on the corresponding template parameter lists. But
// assume that empty parameter lists are supposed to match this
// template-id.
if (IsFriend && T->isDependentType()) {
if (ParamIdx < ParamLists.size() &&
DependsOnTemplateParameters(T, ParamLists[ParamIdx]))
ExpectedTemplateParams = nullptr;
else
continue;
}
if (ParamIdx < ParamLists.size()) {
// Check the template parameter list, if we can.
if (ExpectedTemplateParams &&
!TemplateParameterListsAreEqual(ParamLists[ParamIdx],
ExpectedTemplateParams,
!SuppressDiagnostic, TPL_TemplateMatch))
Invalid = true;
if (!Invalid &&
CheckTemplateParameterList(ParamLists[ParamIdx], nullptr,
TPC_ClassTemplateMember))
Invalid = true;
++ParamIdx;
continue;
}
if (!SuppressDiagnostic)
Diag(DeclLoc, diag::err_template_spec_needs_template_parameters)
<< T
<< getRangeOfTypeInNestedNameSpecifier(Context, T, SS);
Invalid = true;
continue;
}
}
// If there were at least as many template-ids as there were template
// parameter lists, then there are no template parameter lists remaining for
// the declaration itself.
if (ParamIdx >= ParamLists.size()) {
if (TemplateId && !IsFriend) {
// We don't have a template header for the declaration itself, but we
// should.
DiagnoseMissingExplicitSpecialization(SourceRange(TemplateId->LAngleLoc,
TemplateId->RAngleLoc));
// Fabricate an empty template parameter list for the invented header.
return TemplateParameterList::Create(Context, SourceLocation(),
SourceLocation(), None,
SourceLocation(), nullptr);
}
return nullptr;
}
// If there were too many template parameter lists, complain about that now.
if (ParamIdx < ParamLists.size() - 1) {
bool HasAnyExplicitSpecHeader = false;
bool AllExplicitSpecHeaders = true;
for (unsigned I = ParamIdx, E = ParamLists.size() - 1; I != E; ++I) {
if (ParamLists[I]->size() == 0)
HasAnyExplicitSpecHeader = true;
else
AllExplicitSpecHeaders = false;
}
if (!SuppressDiagnostic)
Diag(ParamLists[ParamIdx]->getTemplateLoc(),
AllExplicitSpecHeaders ? diag::warn_template_spec_extra_headers
: diag::err_template_spec_extra_headers)
<< SourceRange(ParamLists[ParamIdx]->getTemplateLoc(),
ParamLists[ParamLists.size() - 2]->getRAngleLoc());
// If there was a specialization somewhere, such that 'template<>' is
// not required, and there were any 'template<>' headers, note where the
// specialization occurred.
if (ExplicitSpecLoc.isValid() && HasAnyExplicitSpecHeader &&
!SuppressDiagnostic)
Diag(ExplicitSpecLoc,
diag::note_explicit_template_spec_does_not_need_header)
<< NestedTypes.back();
// We have a template parameter list with no corresponding scope, which
// means that the resulting template declaration can't be instantiated
// properly (we'll end up with dependent nodes when we shouldn't).
if (!AllExplicitSpecHeaders)
Invalid = true;
}
// C++ [temp.expl.spec]p16:
// In an explicit specialization declaration for a member of a class
// template or a member template that ap- pears in namespace scope, the
// member template and some of its enclosing class templates may remain
// unspecialized, except that the declaration shall not explicitly
// specialize a class member template if its en- closing class templates
// are not explicitly specialized as well.
if (ParamLists.back()->size() == 0 &&
CheckExplicitSpecialization(ParamLists[ParamIdx]->getSourceRange(),
false))
return nullptr;
// Return the last template parameter list, which corresponds to the
// entity being declared.
return ParamLists.back();
}
void Sema::NoteAllFoundTemplates(TemplateName Name) {
if (TemplateDecl *Template = Name.getAsTemplateDecl()) {
Diag(Template->getLocation(), diag::note_template_declared_here)
<< (isa<FunctionTemplateDecl>(Template)
? 0
: isa<ClassTemplateDecl>(Template)
? 1
: isa<VarTemplateDecl>(Template)
? 2
: isa<TypeAliasTemplateDecl>(Template) ? 3 : 4)
<< Template->getDeclName();
return;
}
if (OverloadedTemplateStorage *OST = Name.getAsOverloadedTemplate()) {
for (OverloadedTemplateStorage::iterator I = OST->begin(),
IEnd = OST->end();
I != IEnd; ++I)
Diag((*I)->getLocation(), diag::note_template_declared_here)
<< 0 << (*I)->getDeclName();
return;
}
}
static QualType
checkBuiltinTemplateIdType(Sema &SemaRef, BuiltinTemplateDecl *BTD,
const SmallVectorImpl<TemplateArgument> &Converted,
SourceLocation TemplateLoc,
TemplateArgumentListInfo &TemplateArgs) {
ASTContext &Context = SemaRef.getASTContext();
switch (BTD->getBuiltinTemplateKind()) {
case BTK__make_integer_seq: {
// Specializations of __make_integer_seq<S, T, N> are treated like
// S<T, 0, ..., N-1>.
// C++14 [inteseq.intseq]p1:
// T shall be an integer type.
if (!Converted[1].getAsType()->isIntegralType(Context)) {
SemaRef.Diag(TemplateArgs[1].getLocation(),
diag::err_integer_sequence_integral_element_type);
return QualType();
}
// C++14 [inteseq.make]p1:
// If N is negative the program is ill-formed.
TemplateArgument NumArgsArg = Converted[2];
llvm::APSInt NumArgs = NumArgsArg.getAsIntegral();
if (NumArgs < 0) {
SemaRef.Diag(TemplateArgs[2].getLocation(),
diag::err_integer_sequence_negative_length);
return QualType();
}
QualType ArgTy = NumArgsArg.getIntegralType();
TemplateArgumentListInfo SyntheticTemplateArgs;
// The type argument gets reused as the first template argument in the
// synthetic template argument list.
SyntheticTemplateArgs.addArgument(TemplateArgs[1]);
// Expand N into 0 ... N-1.
for (llvm::APSInt I(NumArgs.getBitWidth(), NumArgs.isUnsigned());
I < NumArgs; ++I) {
TemplateArgument TA(Context, I, ArgTy);
SyntheticTemplateArgs.addArgument(SemaRef.getTrivialTemplateArgumentLoc(
TA, ArgTy, TemplateArgs[2].getLocation()));
}
// The first template argument will be reused as the template decl that
// our synthetic template arguments will be applied to.
return SemaRef.CheckTemplateIdType(Converted[0].getAsTemplate(),
TemplateLoc, SyntheticTemplateArgs);
}
case BTK__type_pack_element:
// Specializations of
// __type_pack_element<Index, T_1, ..., T_N>
// are treated like T_Index.
assert(Converted.size() == 2 &&
"__type_pack_element should be given an index and a parameter pack");
// If the Index is out of bounds, the program is ill-formed.
TemplateArgument IndexArg = Converted[0], Ts = Converted[1];
llvm::APSInt Index = IndexArg.getAsIntegral();
assert(Index >= 0 && "the index used with __type_pack_element should be of "
"type std::size_t, and hence be non-negative");
if (Index >= Ts.pack_size()) {
SemaRef.Diag(TemplateArgs[0].getLocation(),
diag::err_type_pack_element_out_of_bounds);
return QualType();
}
// We simply return the type at index `Index`.
auto Nth = std::next(Ts.pack_begin(), Index.getExtValue());
return Nth->getAsType();
}
llvm_unreachable("unexpected BuiltinTemplateDecl!");
}
/// Determine whether this alias template is "enable_if_t".
/// libc++ >=14 uses "__enable_if_t" in C++11 mode.
static bool isEnableIfAliasTemplate(TypeAliasTemplateDecl *AliasTemplate) {
return AliasTemplate->getName().equals("enable_if_t") ||
AliasTemplate->getName().equals("__enable_if_t");
}
/// Collect all of the separable terms in the given condition, which
/// might be a conjunction.
///
/// FIXME: The right answer is to convert the logical expression into
/// disjunctive normal form, so we can find the first failed term
/// within each possible clause.
static void collectConjunctionTerms(Expr *Clause,
SmallVectorImpl<Expr *> &Terms) {
if (auto BinOp = dyn_cast<BinaryOperator>(Clause->IgnoreParenImpCasts())) {
if (BinOp->getOpcode() == BO_LAnd) {
collectConjunctionTerms(BinOp->getLHS(), Terms);
collectConjunctionTerms(BinOp->getRHS(), Terms);
}
return;
}
Terms.push_back(Clause);
}
// The ranges-v3 library uses an odd pattern of a top-level "||" with
// a left-hand side that is value-dependent but never true. Identify
// the idiom and ignore that term.
static Expr *lookThroughRangesV3Condition(Preprocessor &PP, Expr *Cond) {
// Top-level '||'.
auto *BinOp = dyn_cast<BinaryOperator>(Cond->IgnoreParenImpCasts());
if (!BinOp) return Cond;
if (BinOp->getOpcode() != BO_LOr) return Cond;
// With an inner '==' that has a literal on the right-hand side.
Expr *LHS = BinOp->getLHS();
auto *InnerBinOp = dyn_cast<BinaryOperator>(LHS->IgnoreParenImpCasts());
if (!InnerBinOp) return Cond;
if (InnerBinOp->getOpcode() != BO_EQ ||
!isa<IntegerLiteral>(InnerBinOp->getRHS()))
return Cond;
// If the inner binary operation came from a macro expansion named
// CONCEPT_REQUIRES or CONCEPT_REQUIRES_, return the right-hand side
// of the '||', which is the real, user-provided condition.
SourceLocation Loc = InnerBinOp->getExprLoc();
if (!Loc.isMacroID()) return Cond;
StringRef MacroName = PP.getImmediateMacroName(Loc);
if (MacroName == "CONCEPT_REQUIRES" || MacroName == "CONCEPT_REQUIRES_")
return BinOp->getRHS();
return Cond;
}
namespace {
// A PrinterHelper that prints more helpful diagnostics for some sub-expressions
// within failing boolean expression, such as substituting template parameters
// for actual types.
class FailedBooleanConditionPrinterHelper : public PrinterHelper {
public:
explicit FailedBooleanConditionPrinterHelper(const PrintingPolicy &P)
: Policy(P) {}
bool handledStmt(Stmt *E, raw_ostream &OS) override {
const auto *DR = dyn_cast<DeclRefExpr>(E);
if (DR && DR->getQualifier()) {
// If this is a qualified name, expand the template arguments in nested
// qualifiers.
DR->getQualifier()->print(OS, Policy, true);
// Then print the decl itself.
const ValueDecl *VD = DR->getDecl();
OS << VD->getName();
if (const auto *IV = dyn_cast<VarTemplateSpecializationDecl>(VD)) {
// This is a template variable, print the expanded template arguments.
printTemplateArgumentList(
OS, IV->getTemplateArgs().asArray(), Policy,
IV->getSpecializedTemplate()->getTemplateParameters());
}
return true;
}
return false;
}
private:
const PrintingPolicy Policy;
};
} // end anonymous namespace
std::pair<Expr *, std::string>
Sema::findFailedBooleanCondition(Expr *Cond) {
Cond = lookThroughRangesV3Condition(PP, Cond);
// Separate out all of the terms in a conjunction.
SmallVector<Expr *, 4> Terms;
collectConjunctionTerms(Cond, Terms);
// Determine which term failed.
Expr *FailedCond = nullptr;
for (Expr *Term : Terms) {
Expr *TermAsWritten = Term->IgnoreParenImpCasts();
// Literals are uninteresting.
if (isa<CXXBoolLiteralExpr>(TermAsWritten) ||
isa<IntegerLiteral>(TermAsWritten))
continue;
// The initialization of the parameter from the argument is
// a constant-evaluated context.
EnterExpressionEvaluationContext ConstantEvaluated(
*this, Sema::ExpressionEvaluationContext::ConstantEvaluated);
bool Succeeded;
if (Term->EvaluateAsBooleanCondition(Succeeded, Context) &&
!Succeeded) {
FailedCond = TermAsWritten;
break;
}
}
if (!FailedCond)
FailedCond = Cond->IgnoreParenImpCasts();
std::string Description;
{
llvm::raw_string_ostream Out(Description);
PrintingPolicy Policy = getPrintingPolicy();
Policy.PrintCanonicalTypes = true;
FailedBooleanConditionPrinterHelper Helper(Policy);
FailedCond->printPretty(Out, &Helper, Policy, 0, "\n", nullptr);
}
return { FailedCond, Description };
}
QualType Sema::CheckTemplateIdType(TemplateName Name,
SourceLocation TemplateLoc,
TemplateArgumentListInfo &TemplateArgs) {
DependentTemplateName *DTN
= Name.getUnderlying().getAsDependentTemplateName();
if (DTN && DTN->isIdentifier())
// When building a template-id where the template-name is dependent,
// assume the template is a type template. Either our assumption is
// correct, or the code is ill-formed and will be diagnosed when the
// dependent name is substituted.
return Context.getDependentTemplateSpecializationType(ETK_None,
DTN->getQualifier(),
DTN->getIdentifier(),
TemplateArgs);
if (Name.getAsAssumedTemplateName() &&
resolveAssumedTemplateNameAsType(/*Scope*/nullptr, Name, TemplateLoc))
return QualType();
TemplateDecl *Template = Name.getAsTemplateDecl();
if (!Template || isa<FunctionTemplateDecl>(Template) ||
isa<VarTemplateDecl>(Template) || isa<ConceptDecl>(Template)) {
// We might have a substituted template template parameter pack. If so,
// build a template specialization type for it.
if (Name.getAsSubstTemplateTemplateParmPack())
return Context.getTemplateSpecializationType(Name, TemplateArgs);
Diag(TemplateLoc, diag::err_template_id_not_a_type)
<< Name;
NoteAllFoundTemplates(Name);
return QualType();
}
// Check that the template argument list is well-formed for this
// template.
SmallVector<TemplateArgument, 4> Converted;
if (CheckTemplateArgumentList(Template, TemplateLoc, TemplateArgs,
false, Converted,
/*UpdateArgsWithConversions=*/true))
return QualType();
QualType CanonType;
if (TypeAliasTemplateDecl *AliasTemplate =
dyn_cast<TypeAliasTemplateDecl>(Template)) {
// Find the canonical type for this type alias template specialization.
TypeAliasDecl *Pattern = AliasTemplate->getTemplatedDecl();
if (Pattern->isInvalidDecl())
return QualType();
TemplateArgumentList StackTemplateArgs(TemplateArgumentList::OnStack,
Converted);
// Only substitute for the innermost template argument list.
MultiLevelTemplateArgumentList TemplateArgLists;
TemplateArgLists.addOuterTemplateArguments(&StackTemplateArgs);
TemplateArgLists.addOuterRetainedLevels(
AliasTemplate->getTemplateParameters()->getDepth());
LocalInstantiationScope Scope(*this);
InstantiatingTemplate Inst(*this, TemplateLoc, Template);
if (Inst.isInvalid())
return QualType();
CanonType = SubstType(Pattern->getUnderlyingType(),
TemplateArgLists, AliasTemplate->getLocation(),
AliasTemplate->getDeclName());
if (CanonType.isNull()) {
// If this was enable_if and we failed to find the nested type
// within enable_if in a SFINAE context, dig out the specific
// enable_if condition that failed and present that instead.
if (isEnableIfAliasTemplate(AliasTemplate)) {
if (auto DeductionInfo = isSFINAEContext()) {
if (*DeductionInfo &&
(*DeductionInfo)->hasSFINAEDiagnostic() &&
(*DeductionInfo)->peekSFINAEDiagnostic().second.getDiagID() ==
diag::err_typename_nested_not_found_enable_if &&
TemplateArgs[0].getArgument().getKind()
== TemplateArgument::Expression) {
Expr *FailedCond;
std::string FailedDescription;
std::tie(FailedCond, FailedDescription) =
findFailedBooleanCondition(TemplateArgs[0].getSourceExpression());
// Remove the old SFINAE diagnostic.
PartialDiagnosticAt OldDiag =
{SourceLocation(), PartialDiagnostic::NullDiagnostic()};
(*DeductionInfo)->takeSFINAEDiagnostic(OldDiag);
// Add a new SFINAE diagnostic specifying which condition
// failed.
(*DeductionInfo)->addSFINAEDiagnostic(
OldDiag.first,
PDiag(diag::err_typename_nested_not_found_requirement)
<< FailedDescription
<< FailedCond->getSourceRange());
}
}
}
return QualType();
}
} else if (Name.isDependent() ||
TemplateSpecializationType::anyDependentTemplateArguments(
TemplateArgs, Converted)) {
// This class template specialization is a dependent
// type. Therefore, its canonical type is another class template
// specialization type that contains all of the converted
// arguments in canonical form. This ensures that, e.g., A<T> and
// A<T, T> have identical types when A is declared as:
//
// template<typename T, typename U = T> struct A;
CanonType = Context.getCanonicalTemplateSpecializationType(Name, Converted);
// This might work out to be a current instantiation, in which
// case the canonical type needs to be the InjectedClassNameType.
//
// TODO: in theory this could be a simple hashtable lookup; most
// changes to CurContext don't change the set of current
// instantiations.
if (isa<ClassTemplateDecl>(Template)) {
for (DeclContext *Ctx = CurContext; Ctx; Ctx = Ctx->getLookupParent()) {
// If we get out to a namespace, we're done.
if (Ctx->isFileContext()) break;
// If this isn't a record, keep looking.
CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Ctx);
if (!Record) continue;
// Look for one of the two cases with InjectedClassNameTypes
// and check whether it's the same template.
if (!isa<ClassTemplatePartialSpecializationDecl>(Record) &&
!Record->getDescribedClassTemplate())
continue;
// Fetch the injected class name type and check whether its
// injected type is equal to the type we just built.
QualType ICNT = Context.getTypeDeclType(Record);
QualType Injected = cast<InjectedClassNameType>(ICNT)
->getInjectedSpecializationType();
if (CanonType != Injected->getCanonicalTypeInternal())
continue;
// If so, the canonical type of this TST is the injected
// class name type of the record we just found.
assert(ICNT.isCanonical());
CanonType = ICNT;
break;
}
}
} else if (ClassTemplateDecl *ClassTemplate
= dyn_cast<ClassTemplateDecl>(Template)) {
// Find the class template specialization declaration that
// corresponds to these arguments.
void *InsertPos = nullptr;
ClassTemplateSpecializationDecl *Decl
= ClassTemplate->findSpecialization(Converted, InsertPos);
if (!Decl) {
// This is the first time we have referenced this class template
// specialization. Create the canonical declaration and add it to
// the set of specializations.
Decl = ClassTemplateSpecializationDecl::Create(
Context, ClassTemplate->getTemplatedDecl()->getTagKind(),
ClassTemplate->getDeclContext(),
ClassTemplate->getTemplatedDecl()->getBeginLoc(),
ClassTemplate->getLocation(), ClassTemplate, Converted, nullptr);
ClassTemplate->AddSpecialization(Decl, InsertPos);
if (ClassTemplate->isOutOfLine())
Decl->setLexicalDeclContext(ClassTemplate->getLexicalDeclContext());
}
if (Decl->getSpecializationKind() == TSK_Undeclared &&
ClassTemplate->getTemplatedDecl()->hasAttrs()) {
InstantiatingTemplate Inst(*this, TemplateLoc, Decl);
if (!Inst.isInvalid()) {
MultiLevelTemplateArgumentList TemplateArgLists;
TemplateArgLists.addOuterTemplateArguments(Converted);
InstantiateAttrsForDecl(TemplateArgLists,
ClassTemplate->getTemplatedDecl(), Decl);
}
}
// Diagnose uses of this specialization.
(void)DiagnoseUseOfDecl(Decl, TemplateLoc);
CanonType = Context.getTypeDeclType(Decl);
assert(isa<RecordType>(CanonType) &&
"type of non-dependent specialization is not a RecordType");
} else if (auto *BTD = dyn_cast<BuiltinTemplateDecl>(Template)) {
CanonType = checkBuiltinTemplateIdType(*this, BTD, Converted, TemplateLoc,
TemplateArgs);
}
// Build the fully-sugared type for this class template
// specialization, which refers back to the class template
// specialization we created or found.
return Context.getTemplateSpecializationType(Name, TemplateArgs, CanonType);
}
void Sema::ActOnUndeclaredTypeTemplateName(Scope *S, TemplateTy &ParsedName,
TemplateNameKind &TNK,
SourceLocation NameLoc,
IdentifierInfo *&II) {
assert(TNK == TNK_Undeclared_template && "not an undeclared template name");
TemplateName Name = ParsedName.get();
auto *ATN = Name.getAsAssumedTemplateName();
assert(ATN && "not an assumed template name");
II = ATN->getDeclName().getAsIdentifierInfo();
if (!resolveAssumedTemplateNameAsType(S, Name, NameLoc, /*Diagnose*/false)) {
// Resolved to a type template name.
ParsedName = TemplateTy::make(Name);
TNK = TNK_Type_template;
}
}
bool Sema::resolveAssumedTemplateNameAsType(Scope *S, TemplateName &Name,
SourceLocation NameLoc,
bool Diagnose) {
// We assumed this undeclared identifier to be an (ADL-only) function
// template name, but it was used in a context where a type was required.
// Try to typo-correct it now.
AssumedTemplateStorage *ATN = Name.getAsAssumedTemplateName();
assert(ATN && "not an assumed template name");
LookupResult R(*this, ATN->getDeclName(), NameLoc, LookupOrdinaryName);
struct CandidateCallback : CorrectionCandidateCallback {
bool ValidateCandidate(const TypoCorrection &TC) override {
return TC.getCorrectionDecl() &&
getAsTypeTemplateDecl(TC.getCorrectionDecl());
}
std::unique_ptr<CorrectionCandidateCallback> clone() override {
return std::make_unique<CandidateCallback>(*this);
}
} FilterCCC;
TypoCorrection Corrected =
CorrectTypo(R.getLookupNameInfo(), R.getLookupKind(), S, nullptr,
FilterCCC, CTK_ErrorRecovery);
if (Corrected && Corrected.getFoundDecl()) {
diagnoseTypo(Corrected, PDiag(diag::err_no_template_suggest)
<< ATN->getDeclName());
Name = TemplateName(Corrected.getCorrectionDeclAs<TemplateDecl>());
return false;
}
if (Diagnose)
Diag(R.getNameLoc(), diag::err_no_template) << R.getLookupName();
return true;
}
TypeResult Sema::ActOnTemplateIdType(
Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
TemplateTy TemplateD, IdentifierInfo *TemplateII,
SourceLocation TemplateIILoc, SourceLocation LAngleLoc,
ASTTemplateArgsPtr TemplateArgsIn, SourceLocation RAngleLoc,
bool IsCtorOrDtorName, bool IsClassName) {
if (SS.isInvalid())
return true;
if (!IsCtorOrDtorName && !IsClassName && SS.isSet()) {
DeclContext *LookupCtx = computeDeclContext(SS, /*EnteringContext*/false);
// C++ [temp.res]p3:
// A qualified-id that refers to a type and in which the
// nested-name-specifier depends on a template-parameter (14.6.2)
// shall be prefixed by the keyword typename to indicate that the
// qualified-id denotes a type, forming an
// elaborated-type-specifier (7.1.5.3).
if (!LookupCtx && isDependentScopeSpecifier(SS)) {
Diag(SS.getBeginLoc(), diag::err_typename_missing_template)
<< SS.getScopeRep() << TemplateII->getName();
// Recover as if 'typename' were specified.
// FIXME: This is not quite correct recovery as we don't transform SS
// into the corresponding dependent form (and we don't diagnose missing
// 'template' keywords within SS as a result).
return ActOnTypenameType(nullptr, SourceLocation(), SS, TemplateKWLoc,
TemplateD, TemplateII, TemplateIILoc, LAngleLoc,
TemplateArgsIn, RAngleLoc);
}
// Per C++ [class.qual]p2, if the template-id was an injected-class-name,
// it's not actually allowed to be used as a type in most cases. Because
// we annotate it before we know whether it's valid, we have to check for
// this case here.
auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(LookupCtx);
if (LookupRD && LookupRD->getIdentifier() == TemplateII) {
Diag(TemplateIILoc,
TemplateKWLoc.isInvalid()
? diag::err_out_of_line_qualified_id_type_names_constructor
: diag::ext_out_of_line_qualified_id_type_names_constructor)
<< TemplateII << 0 /*injected-class-name used as template name*/
<< 1 /*if any keyword was present, it was 'template'*/;
}
}
TemplateName Template = TemplateD.get();
if (Template.getAsAssumedTemplateName() &&
resolveAssumedTemplateNameAsType(S, Template, TemplateIILoc))
return true;
// Translate the parser's template argument list in our AST format.
TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
translateTemplateArguments(TemplateArgsIn, TemplateArgs);
if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
QualType T
= Context.getDependentTemplateSpecializationType(ETK_None,
DTN->getQualifier(),
DTN->getIdentifier(),
TemplateArgs);
// Build type-source information.
TypeLocBuilder TLB;
DependentTemplateSpecializationTypeLoc SpecTL
= TLB.push<DependentTemplateSpecializationTypeLoc>(T);
SpecTL.setElaboratedKeywordLoc(SourceLocation());
SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
SpecTL.setTemplateNameLoc(TemplateIILoc);
SpecTL.setLAngleLoc(LAngleLoc);
SpecTL.setRAngleLoc(RAngleLoc);
for (unsigned I = 0, N = SpecTL.getNumArgs(); I != N; ++I)
SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
return CreateParsedType(T, TLB.getTypeSourceInfo(Context, T));
}
QualType Result = CheckTemplateIdType(Template, TemplateIILoc, TemplateArgs);
if (Result.isNull())
return true;
// Build type-source information.
TypeLocBuilder TLB;
TemplateSpecializationTypeLoc SpecTL
= TLB.push<TemplateSpecializationTypeLoc>(Result);
SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
SpecTL.setTemplateNameLoc(TemplateIILoc);
SpecTL.setLAngleLoc(LAngleLoc);
SpecTL.setRAngleLoc(RAngleLoc);
for (unsigned i = 0, e = SpecTL.getNumArgs(); i != e; ++i)
SpecTL.setArgLocInfo(i, TemplateArgs[i].getLocInfo());
// NOTE: avoid constructing an ElaboratedTypeLoc if this is a
// constructor or destructor name (in such a case, the scope specifier
// will be attached to the enclosing Decl or Expr node).
if (SS.isNotEmpty() && !IsCtorOrDtorName) {
// Create an elaborated-type-specifier containing the nested-name-specifier.
Result = Context.getElaboratedType(ETK_None, SS.getScopeRep(), Result);
ElaboratedTypeLoc ElabTL = TLB.push<ElaboratedTypeLoc>(Result);
ElabTL.setElaboratedKeywordLoc(SourceLocation());
ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
}
return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
}
TypeResult Sema::ActOnTagTemplateIdType(TagUseKind TUK,
TypeSpecifierType TagSpec,
SourceLocation TagLoc,
CXXScopeSpec &SS,
SourceLocation TemplateKWLoc,
TemplateTy TemplateD,
SourceLocation TemplateLoc,
SourceLocation LAngleLoc,
ASTTemplateArgsPtr TemplateArgsIn,
SourceLocation RAngleLoc) {
if (SS.isInvalid())
return TypeResult(true);
TemplateName Template = TemplateD.get();
// Translate the parser's template argument list in our AST format.
TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
translateTemplateArguments(TemplateArgsIn, TemplateArgs);
// Determine the tag kind
TagTypeKind TagKind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
ElaboratedTypeKeyword Keyword
= TypeWithKeyword::getKeywordForTagTypeKind(TagKind);
if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
QualType T = Context.getDependentTemplateSpecializationType(Keyword,
DTN->getQualifier(),
DTN->getIdentifier(),
TemplateArgs);
// Build type-source information.
TypeLocBuilder TLB;
DependentTemplateSpecializationTypeLoc SpecTL
= TLB.push<DependentTemplateSpecializationTypeLoc>(T);
SpecTL.setElaboratedKeywordLoc(TagLoc);
SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
SpecTL.setTemplateNameLoc(TemplateLoc);
SpecTL.setLAngleLoc(LAngleLoc);
SpecTL.setRAngleLoc(RAngleLoc);
for (unsigned I = 0, N = SpecTL.getNumArgs(); I != N; ++I)
SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
return CreateParsedType(T, TLB.getTypeSourceInfo(Context, T));
}
if (TypeAliasTemplateDecl *TAT =
dyn_cast_or_null<TypeAliasTemplateDecl>(Template.getAsTemplateDecl())) {
// C++0x [dcl.type.elab]p2:
// If the identifier resolves to a typedef-name or the simple-template-id
// resolves to an alias template specialization, the
// elaborated-type-specifier is ill-formed.
Diag(TemplateLoc, diag::err_tag_reference_non_tag)
<< TAT << NTK_TypeAliasTemplate << TagKind;
Diag(TAT->getLocation(), diag::note_declared_at);
}
QualType Result = CheckTemplateIdType(Template, TemplateLoc, TemplateArgs);
if (Result.isNull())
return TypeResult(true);
// Check the tag kind
if (const RecordType *RT = Result->getAs<RecordType>()) {
RecordDecl *D = RT->getDecl();
IdentifierInfo *Id = D->getIdentifier();
assert(Id && "templated class must have an identifier");
if (!isAcceptableTagRedeclaration(D, TagKind, TUK == TUK_Definition,
TagLoc, Id)) {
Diag(TagLoc, diag::err_use_with_wrong_tag)
<< Result
<< FixItHint::CreateReplacement(SourceRange(TagLoc), D->getKindName());
Diag(D->getLocation(), diag::note_previous_use);
}
}
// Provide source-location information for the template specialization.
TypeLocBuilder TLB;
TemplateSpecializationTypeLoc SpecTL
= TLB.push<TemplateSpecializationTypeLoc>(Result);
SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
SpecTL.setTemplateNameLoc(TemplateLoc);
SpecTL.setLAngleLoc(LAngleLoc);
SpecTL.setRAngleLoc(RAngleLoc);
for (unsigned i = 0, e = SpecTL.getNumArgs(); i != e; ++i)
SpecTL.setArgLocInfo(i, TemplateArgs[i].getLocInfo());
// Construct an elaborated type containing the nested-name-specifier (if any)
// and tag keyword.
Result = Context.getElaboratedType(Keyword, SS.getScopeRep(), Result);
ElaboratedTypeLoc ElabTL = TLB.push<ElaboratedTypeLoc>(Result);
ElabTL.setElaboratedKeywordLoc(TagLoc);
ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
}
static bool CheckTemplateSpecializationScope(Sema &S, NamedDecl *Specialized,
NamedDecl *PrevDecl,
SourceLocation Loc,
bool IsPartialSpecialization);
static TemplateSpecializationKind getTemplateSpecializationKind(Decl *D);
static bool isTemplateArgumentTemplateParameter(
const TemplateArgument &Arg, unsigned Depth, unsigned Index) {
switch (Arg.getKind()) {
case TemplateArgument::Null:
case TemplateArgument::NullPtr:
case TemplateArgument::Integral:
case TemplateArgument::Declaration:
case TemplateArgument::Pack:
case TemplateArgument::TemplateExpansion:
return false;
case TemplateArgument::Type: {
QualType Type = Arg.getAsType();
const TemplateTypeParmType *TPT =
Arg.getAsType()->getAs<TemplateTypeParmType>();
return TPT && !Type.hasQualifiers() &&
TPT->getDepth() == Depth && TPT->getIndex() == Index;
}
case TemplateArgument::Expression: {
DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg.getAsExpr());
if (!DRE || !DRE->getDecl())
return false;
const NonTypeTemplateParmDecl *NTTP =
dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl());
return NTTP && NTTP->getDepth() == Depth && NTTP->getIndex() == Index;
}
case TemplateArgument::Template:
const TemplateTemplateParmDecl *TTP =
dyn_cast_or_null<TemplateTemplateParmDecl>(
Arg.getAsTemplateOrTemplatePattern().getAsTemplateDecl());
return TTP && TTP->getDepth() == Depth && TTP->getIndex() == Index;
}
llvm_unreachable("unexpected kind of template argument");
}
static bool isSameAsPrimaryTemplate(TemplateParameterList *Params,
ArrayRef<TemplateArgument> Args) {
if (Params->size() != Args.size())
return false;
unsigned Depth = Params->getDepth();
for (unsigned I = 0, N = Args.size(); I != N; ++I) {
TemplateArgument Arg = Args[I];
// If the parameter is a pack expansion, the argument must be a pack
// whose only element is a pack expansion.
if (Params->getParam(I)->isParameterPack()) {
if (Arg.getKind() != TemplateArgument::Pack || Arg.pack_size() != 1 ||
!Arg.pack_begin()->isPackExpansion())
return false;
Arg = Arg.pack_begin()->getPackExpansionPattern();
}
if (!isTemplateArgumentTemplateParameter(Arg, Depth, I))
return false;
}
return true;
}
template<typename PartialSpecDecl>
static void checkMoreSpecializedThanPrimary(Sema &S, PartialSpecDecl *Partial) {
if (Partial->getDeclContext()->isDependentContext())
return;
// FIXME: Get the TDK from deduction in order to provide better diagnostics
// for non-substitution-failure issues?
TemplateDeductionInfo Info(Partial->getLocation());
if (S.isMoreSpecializedThanPrimary(Partial, Info))
return;
auto *Template = Partial->getSpecializedTemplate();
S.Diag(Partial->getLocation(),
diag::ext_partial_spec_not_more_specialized_than_primary)
<< isa<VarTemplateDecl>(Template);
if (Info.hasSFINAEDiagnostic()) {
PartialDiagnosticAt Diag = {SourceLocation(),
PartialDiagnostic::NullDiagnostic()};
Info.takeSFINAEDiagnostic(Diag);
SmallString<128> SFINAEArgString;
Diag.second.EmitToString(S.getDiagnostics(), SFINAEArgString);
S.Diag(Diag.first,
diag::note_partial_spec_not_more_specialized_than_primary)
<< SFINAEArgString;
}
S.Diag(Template->getLocation(), diag::note_template_decl_here);
SmallVector<const Expr *, 3> PartialAC, TemplateAC;
Template->getAssociatedConstraints(TemplateAC);
Partial->getAssociatedConstraints(PartialAC);
S.MaybeEmitAmbiguousAtomicConstraintsDiagnostic(Partial, PartialAC, Template,
TemplateAC);
}
static void
noteNonDeducibleParameters(Sema &S, TemplateParameterList *TemplateParams,
const llvm::SmallBitVector &DeducibleParams) {
for (unsigned I = 0, N = DeducibleParams.size(); I != N; ++I) {
if (!DeducibleParams[I]) {
NamedDecl *Param = TemplateParams->getParam(I);
if (Param->getDeclName())
S.Diag(Param->getLocation(), diag::note_non_deducible_parameter)
<< Param->getDeclName();
else
S.Diag(Param->getLocation(), diag::note_non_deducible_parameter)
<< "(anonymous)";
}
}
}
template<typename PartialSpecDecl>
static void checkTemplatePartialSpecialization(Sema &S,
PartialSpecDecl *Partial) {
// C++1z [temp.class.spec]p8: (DR1495)
// - The specialization shall be more specialized than the primary
// template (14.5.5.2).
checkMoreSpecializedThanPrimary(S, Partial);
// C++ [temp.class.spec]p8: (DR1315)
// - Each template-parameter shall appear at least once in the
// template-id outside a non-deduced context.
// C++1z [temp.class.spec.match]p3 (P0127R2)
// If the template arguments of a partial specialization cannot be
// deduced because of the structure of its template-parameter-list
// and the template-id, the program is ill-formed.
auto *TemplateParams = Partial->getTemplateParameters();
llvm::SmallBitVector DeducibleParams(TemplateParams->size());
S.MarkUsedTemplateParameters(Partial->getTemplateArgs(), true,
TemplateParams->getDepth(), DeducibleParams);
if (!DeducibleParams.all()) {
unsigned NumNonDeducible = DeducibleParams.size() - DeducibleParams.count();
S.Diag(Partial->getLocation(), diag::ext_partial_specs_not_deducible)
<< isa<VarTemplatePartialSpecializationDecl>(Partial)
<< (NumNonDeducible > 1)
<< SourceRange(Partial->getLocation(),
Partial->getTemplateArgsAsWritten()->RAngleLoc);
noteNonDeducibleParameters(S, TemplateParams, DeducibleParams);
}
}
void Sema::CheckTemplatePartialSpecialization(
ClassTemplatePartialSpecializationDecl *Partial) {
checkTemplatePartialSpecialization(*this, Partial);
}
void Sema::CheckTemplatePartialSpecialization(
VarTemplatePartialSpecializationDecl *Partial) {
checkTemplatePartialSpecialization(*this, Partial);
}
void Sema::CheckDeductionGuideTemplate(FunctionTemplateDecl *TD) {
// C++1z [temp.param]p11:
// A template parameter of a deduction guide template that does not have a
// default-argument shall be deducible from the parameter-type-list of the
// deduction guide template.
auto *TemplateParams = TD->getTemplateParameters();
llvm::SmallBitVector DeducibleParams(TemplateParams->size());
MarkDeducedTemplateParameters(TD, DeducibleParams);
for (unsigned I = 0; I != TemplateParams->size(); ++I) {
// A parameter pack is deducible (to an empty pack).
auto *Param = TemplateParams->getParam(I);
if (Param->isParameterPack() || hasVisibleDefaultArgument(Param))
DeducibleParams[I] = true;
}
if (!DeducibleParams.all()) {
unsigned NumNonDeducible = DeducibleParams.size() - DeducibleParams.count();
Diag(TD->getLocation(), diag::err_deduction_guide_template_not_deducible)
<< (NumNonDeducible > 1);
noteNonDeducibleParameters(*this, TemplateParams, DeducibleParams);
}
}
DeclResult Sema::ActOnVarTemplateSpecialization(
Scope *S, Declarator &D, TypeSourceInfo *DI, SourceLocation TemplateKWLoc,
TemplateParameterList *TemplateParams, StorageClass SC,
bool IsPartialSpecialization) {
// D must be variable template id.
assert(D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId &&
"Variable template specialization is declared with a template id.");
TemplateIdAnnotation *TemplateId = D.getName().TemplateId;
TemplateArgumentListInfo TemplateArgs =
makeTemplateArgumentListInfo(*this, *TemplateId);
SourceLocation TemplateNameLoc = D.getIdentifierLoc();
SourceLocation LAngleLoc = TemplateId->LAngleLoc;
SourceLocation RAngleLoc = TemplateId->RAngleLoc;
TemplateName Name = TemplateId->Template.get();
// The template-id must name a variable template.
VarTemplateDecl *VarTemplate =
dyn_cast_or_null<VarTemplateDecl>(Name.getAsTemplateDecl());
if (!VarTemplate) {
NamedDecl *FnTemplate;
if (auto *OTS = Name.getAsOverloadedTemplate())
FnTemplate = *OTS->begin();
else
FnTemplate = dyn_cast_or_null<FunctionTemplateDecl>(Name.getAsTemplateDecl());
if (FnTemplate)
return Diag(D.getIdentifierLoc(), diag::err_var_spec_no_template_but_method)
<< FnTemplate->getDeclName();
return Diag(D.getIdentifierLoc(), diag::err_var_spec_no_template)
<< IsPartialSpecialization;
}
// Check for unexpanded parameter packs in any of the template arguments.
for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
if (DiagnoseUnexpandedParameterPack(TemplateArgs[I],
UPPC_PartialSpecialization))
return true;
// Check that the template argument list is well-formed for this
// template.
SmallVector<TemplateArgument, 4> Converted;
if (CheckTemplateArgumentList(VarTemplate, TemplateNameLoc, TemplateArgs,
false, Converted,
/*UpdateArgsWithConversions=*/true))
return true;
// Find the variable template (partial) specialization declaration that
// corresponds to these arguments.
if (IsPartialSpecialization) {
if (CheckTemplatePartialSpecializationArgs(TemplateNameLoc, VarTemplate,
TemplateArgs.size(), Converted))
return true;
// FIXME: Move these checks to CheckTemplatePartialSpecializationArgs so we
// also do them during instantiation.
if (!Name.isDependent() &&
!TemplateSpecializationType::anyDependentTemplateArguments(TemplateArgs,
Converted)) {
Diag(TemplateNameLoc, diag::err_partial_spec_fully_specialized)
<< VarTemplate->getDeclName();
IsPartialSpecialization = false;
}
if (isSameAsPrimaryTemplate(VarTemplate->getTemplateParameters(),
Converted) &&
(!Context.getLangOpts().CPlusPlus20 ||
!TemplateParams->hasAssociatedConstraints())) {
// C++ [temp.class.spec]p9b3:
//
// -- The argument list of the specialization shall not be identical
// to the implicit argument list of the primary template.
Diag(TemplateNameLoc, diag::err_partial_spec_args_match_primary_template)
<< /*variable template*/ 1
<< /*is definition*/(SC != SC_Extern && !CurContext->isRecord())
<< FixItHint::CreateRemoval(SourceRange(LAngleLoc, RAngleLoc));
// FIXME: Recover from this by treating the declaration as a redeclaration
// of the primary template.
return true;
}
}
void *InsertPos = nullptr;
VarTemplateSpecializationDecl *PrevDecl = nullptr;
if (IsPartialSpecialization)
PrevDecl = VarTemplate->findPartialSpecialization(Converted, TemplateParams,
InsertPos);
else
PrevDecl = VarTemplate->findSpecialization(Converted, InsertPos);
VarTemplateSpecializationDecl *Specialization = nullptr;
// Check whether we can declare a variable template specialization in
// the current scope.
if (CheckTemplateSpecializationScope(*this, VarTemplate, PrevDecl,
TemplateNameLoc,
IsPartialSpecialization))
return true;
if (PrevDecl && PrevDecl->getSpecializationKind() == TSK_Undeclared) {
// Since the only prior variable template specialization with these
// arguments was referenced but not declared, reuse that
// declaration node as our own, updating its source location and
// the list of outer template parameters to reflect our new declaration.
Specialization = PrevDecl;
Specialization->setLocation(TemplateNameLoc);
PrevDecl = nullptr;
} else if (IsPartialSpecialization) {
// Create a new class template partial specialization declaration node.
VarTemplatePartialSpecializationDecl *PrevPartial =
cast_or_null<VarTemplatePartialSpecializationDecl>(PrevDecl);
VarTemplatePartialSpecializationDecl *Partial =
VarTemplatePartialSpecializationDecl::Create(
Context, VarTemplate->getDeclContext(), TemplateKWLoc,
TemplateNameLoc, TemplateParams, VarTemplate, DI->getType(), DI, SC,
Converted, TemplateArgs);
if (!PrevPartial)
VarTemplate->AddPartialSpecialization(Partial, InsertPos);
Specialization = Partial;
// If we are providing an explicit specialization of a member variable
// template specialization, make a note of that.
if (PrevPartial && PrevPartial->getInstantiatedFromMember())
PrevPartial->setMemberSpecialization();
CheckTemplatePartialSpecialization(Partial);
} else {
// Create a new class template specialization declaration node for
// this explicit specialization or friend declaration.
Specialization = VarTemplateSpecializationDecl::Create(
Context, VarTemplate->getDeclContext(), TemplateKWLoc, TemplateNameLoc,
VarTemplate, DI->getType(), DI, SC, Converted);
Specialization->setTemplateArgsInfo(TemplateArgs);
if (!PrevDecl)
VarTemplate->AddSpecialization(Specialization, InsertPos);
}
// C++ [temp.expl.spec]p6:
// If a template, a member template or the member of a class template is
// explicitly specialized then that specialization shall be declared
// before the first use of that specialization that would cause an implicit
// instantiation to take place, in every translation unit in which such a
// use occurs; no diagnostic is required.
if (PrevDecl && PrevDecl->getPointOfInstantiation().isValid()) {
bool Okay = false;
for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
// Is there any previous explicit specialization declaration?
if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
Okay = true;
break;
}
}
if (!Okay) {
SourceRange Range(TemplateNameLoc, RAngleLoc);
Diag(TemplateNameLoc, diag::err_specialization_after_instantiation)
<< Name << Range;
Diag(PrevDecl->getPointOfInstantiation(),
diag::note_instantiation_required_here)
<< (PrevDecl->getTemplateSpecializationKind() !=
TSK_ImplicitInstantiation);
return true;
}
}
Specialization->setTemplateKeywordLoc(TemplateKWLoc);
Specialization->setLexicalDeclContext(CurContext);
// Add the specialization into its lexical context, so that it can
// be seen when iterating through the list of declarations in that
// context. However, specializations are not found by name lookup.
CurContext->addDecl(Specialization);
// Note that this is an explicit specialization.
Specialization->setSpecializationKind(TSK_ExplicitSpecialization);
if (PrevDecl) {
// Check that this isn't a redefinition of this specialization,
// merging with previous declarations.
LookupResult PrevSpec(*this, GetNameForDeclarator(D), LookupOrdinaryName,
forRedeclarationInCurContext());
PrevSpec.addDecl(PrevDecl);
D.setRedeclaration(CheckVariableDeclaration(Specialization, PrevSpec));
} else if (Specialization->isStaticDataMember() &&
Specialization->isOutOfLine()) {
Specialization->setAccess(VarTemplate->getAccess());
}
return Specialization;
}
namespace {
/// A partial specialization whose template arguments have matched
/// a given template-id.
struct PartialSpecMatchResult {
VarTemplatePartialSpecializationDecl *Partial;
TemplateArgumentList *Args;
};
} // end anonymous namespace
DeclResult
Sema::CheckVarTemplateId(VarTemplateDecl *Template, SourceLocation TemplateLoc,
SourceLocation TemplateNameLoc,
const TemplateArgumentListInfo &TemplateArgs) {
assert(Template && "A variable template id without template?");
// Check that the template argument list is well-formed for this template.
SmallVector<TemplateArgument, 4> Converted;
if (CheckTemplateArgumentList(
Template, TemplateNameLoc,
const_cast<TemplateArgumentListInfo &>(TemplateArgs), false,
Converted, /*UpdateArgsWithConversions=*/true))
return true;
// Produce a placeholder value if the specialization is dependent.
if (Template->getDeclContext()->isDependentContext() ||
TemplateSpecializationType::anyDependentTemplateArguments(TemplateArgs,
Converted))
return DeclResult();
// Find the variable template specialization declaration that
// corresponds to these arguments.
void *InsertPos = nullptr;
if (VarTemplateSpecializationDecl *Spec = Template->findSpecialization(
Converted, InsertPos)) {
checkSpecializationVisibility(TemplateNameLoc, Spec);
// If we already have a variable template specialization, return it.
return Spec;
}
// This is the first time we have referenced this variable template
// specialization. Create the canonical declaration and add it to
// the set of specializations, based on the closest partial specialization
// that it represents. That is,
VarDecl *InstantiationPattern = Template->getTemplatedDecl();
TemplateArgumentList TemplateArgList(TemplateArgumentList::OnStack,
Converted);
TemplateArgumentList *InstantiationArgs = &TemplateArgList;
bool AmbiguousPartialSpec = false;
typedef PartialSpecMatchResult MatchResult;
SmallVector<MatchResult, 4> Matched;
SourceLocation PointOfInstantiation = TemplateNameLoc;
TemplateSpecCandidateSet FailedCandidates(PointOfInstantiation,
/*ForTakingAddress=*/false);
// 1. Attempt to find the closest partial specialization that this
// specializes, if any.
// TODO: Unify with InstantiateClassTemplateSpecialization()?
// Perhaps better after unification of DeduceTemplateArguments() and
// getMoreSpecializedPartialSpecialization().
SmallVector<VarTemplatePartialSpecializationDecl *, 4> PartialSpecs;
Template->getPartialSpecializations(PartialSpecs);
for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I) {
VarTemplatePartialSpecializationDecl *Partial = PartialSpecs[I];
TemplateDeductionInfo Info(FailedCandidates.getLocation());
if (TemplateDeductionResult Result =
DeduceTemplateArguments(Partial, TemplateArgList, Info)) {
// Store the failed-deduction information for use in diagnostics, later.
// TODO: Actually use the failed-deduction info?
FailedCandidates.addCandidate().set(
DeclAccessPair::make(Template, AS_public), Partial,
MakeDeductionFailureInfo(Context, Result, Info));
(void)Result;
} else {
Matched.push_back(PartialSpecMatchResult());
Matched.back().Partial = Partial;
Matched.back().Args = Info.take();
}
}
if (Matched.size() >= 1) {
SmallVector<MatchResult, 4>::iterator Best = Matched.begin();
if (Matched.size() == 1) {
// -- If exactly one matching specialization is found, the
// instantiation is generated from that specialization.
// We don't need to do anything for this.
} else {
// -- If more than one matching specialization is found, the
// partial order rules (14.5.4.2) are used to determine
// whether one of the specializations is more specialized
// than the others. If none of the specializations is more
// specialized than all of the other matching
// specializations, then the use of the variable template is
// ambiguous and the program is ill-formed.
for (SmallVector<MatchResult, 4>::iterator P = Best + 1,
PEnd = Matched.end();
P != PEnd; ++P) {
if (getMoreSpecializedPartialSpecialization(P->Partial, Best->Partial,
PointOfInstantiation) ==
P->Partial)
Best = P;
}
// Determine if the best partial specialization is more specialized than
// the others.
for (SmallVector<MatchResult, 4>::iterator P = Matched.begin(),
PEnd = Matched.end();
P != PEnd; ++P) {
if (P != Best && getMoreSpecializedPartialSpecialization(
P->Partial, Best->Partial,
PointOfInstantiation) != Best->Partial) {
AmbiguousPartialSpec = true;
break;
}
}
}
// Instantiate using the best variable template partial specialization.
InstantiationPattern = Best->Partial;
InstantiationArgs = Best->Args;
} else {
// -- If no match is found, the instantiation is generated
// from the primary template.
// InstantiationPattern = Template->getTemplatedDecl();
}
// 2. Create the canonical declaration.
// Note that we do not instantiate a definition until we see an odr-use
// in DoMarkVarDeclReferenced().
// FIXME: LateAttrs et al.?
VarTemplateSpecializationDecl *Decl = BuildVarTemplateInstantiation(
Template, InstantiationPattern, *InstantiationArgs, TemplateArgs,
Converted, TemplateNameLoc /*, LateAttrs, StartingScope*/);
if (!Decl)
return true;
if (AmbiguousPartialSpec) {
// Partial ordering did not produce a clear winner. Complain.
Decl->setInvalidDecl();
Diag(PointOfInstantiation, diag::err_partial_spec_ordering_ambiguous)
<< Decl;
// Print the matching partial specializations.
for (MatchResult P : Matched)
Diag(P.Partial->getLocation(), diag::note_partial_spec_match)
<< getTemplateArgumentBindingsText(P.Partial->getTemplateParameters(),
*P.Args);
return true;
}
if (VarTemplatePartialSpecializationDecl *D =
dyn_cast<VarTemplatePartialSpecializationDecl>(InstantiationPattern))
Decl->setInstantiationOf(D, InstantiationArgs);
checkSpecializationVisibility(TemplateNameLoc, Decl);
assert(Decl && "No variable template specialization?");
return Decl;
}
ExprResult
Sema::CheckVarTemplateId(const CXXScopeSpec &SS,
const DeclarationNameInfo &NameInfo,
VarTemplateDecl *Template, SourceLocation TemplateLoc,
const TemplateArgumentListInfo *TemplateArgs) {
DeclResult Decl = CheckVarTemplateId(Template, TemplateLoc, NameInfo.getLoc(),
*TemplateArgs);
if (Decl.isInvalid())
return ExprError();
if (!Decl.get())
return ExprResult();
VarDecl *Var = cast<VarDecl>(Decl.get());
if (!Var->getTemplateSpecializationKind())
Var->setTemplateSpecializationKind(TSK_ImplicitInstantiation,
NameInfo.getLoc());
// Build an ordinary singleton decl ref.
return BuildDeclarationNameExpr(SS, NameInfo, Var,
/*FoundD=*/nullptr, TemplateArgs);
}
void Sema::diagnoseMissingTemplateArguments(TemplateName Name,
SourceLocation Loc) {
Diag(Loc, diag::err_template_missing_args)
<< (int)getTemplateNameKindForDiagnostics(Name) << Name;
if (TemplateDecl *TD = Name.getAsTemplateDecl()) {
Diag(TD->getLocation(), diag::note_template_decl_here)
<< TD->getTemplateParameters()->getSourceRange();
}
}
ExprResult
Sema::CheckConceptTemplateId(const CXXScopeSpec &SS,
SourceLocation TemplateKWLoc,
const DeclarationNameInfo &ConceptNameInfo,
NamedDecl *FoundDecl,
ConceptDecl *NamedConcept,
const TemplateArgumentListInfo *TemplateArgs) {
assert(NamedConcept && "A concept template id without a template?");
llvm::SmallVector<TemplateArgument, 4> Converted;
if (CheckTemplateArgumentList(NamedConcept, ConceptNameInfo.getLoc(),
const_cast<TemplateArgumentListInfo&>(*TemplateArgs),
/*PartialTemplateArgs=*/false, Converted,
/*UpdateArgsWithConversions=*/false))
return ExprError();
ConstraintSatisfaction Satisfaction;
bool AreArgsDependent =
TemplateSpecializationType::anyDependentTemplateArguments(*TemplateArgs,
Converted);
if (!AreArgsDependent &&
CheckConstraintSatisfaction(
NamedConcept, {NamedConcept->getConstraintExpr()}, Converted,
SourceRange(SS.isSet() ? SS.getBeginLoc() : ConceptNameInfo.getLoc(),
TemplateArgs->getRAngleLoc()),
Satisfaction))
return ExprError();
return ConceptSpecializationExpr::Create(Context,
SS.isSet() ? SS.getWithLocInContext(Context) : NestedNameSpecifierLoc{},
TemplateKWLoc, ConceptNameInfo, FoundDecl, NamedConcept,
ASTTemplateArgumentListInfo::Create(Context, *TemplateArgs), Converted,
AreArgsDependent ? nullptr : &Satisfaction);
}
ExprResult Sema::BuildTemplateIdExpr(const CXXScopeSpec &SS,
SourceLocation TemplateKWLoc,
LookupResult &R,
bool RequiresADL,
const TemplateArgumentListInfo *TemplateArgs) {
// FIXME: Can we do any checking at this point? I guess we could check the
// template arguments that we have against the template name, if the template
// name refers to a single template. That's not a terribly common case,
// though.
// foo<int> could identify a single function unambiguously
// This approach does NOT work, since f<int>(1);
// gets resolved prior to resorting to overload resolution
// i.e., template<class T> void f(double);
// vs template<class T, class U> void f(U);
// These should be filtered out by our callers.
assert(!R.isAmbiguous() && "ambiguous lookup when building templateid");
// Non-function templates require a template argument list.
if (auto *TD = R.getAsSingle<TemplateDecl>()) {
if (!TemplateArgs && !isa<FunctionTemplateDecl>(TD)) {
diagnoseMissingTemplateArguments(TemplateName(TD), R.getNameLoc());
return ExprError();
}
}
// In C++1y, check variable template ids.
if (R.getAsSingle<VarTemplateDecl>()) {
ExprResult Res = CheckVarTemplateId(SS, R.getLookupNameInfo(),
R.getAsSingle<VarTemplateDecl>(),
TemplateKWLoc, TemplateArgs);
if (Res.isInvalid() || Res.isUsable())
return Res;
// Result is dependent. Carry on to build an UnresolvedLookupEpxr.
}
if (R.getAsSingle<ConceptDecl>()) {
return CheckConceptTemplateId(SS, TemplateKWLoc, R.getLookupNameInfo(),
R.getFoundDecl(),
R.getAsSingle<ConceptDecl>(), TemplateArgs);
}
// We don't want lookup warnings at this point.
R.suppressDiagnostics();
UnresolvedLookupExpr *ULE
= UnresolvedLookupExpr::Create(Context, R.getNamingClass(),
SS.getWithLocInContext(Context),
TemplateKWLoc,
R.getLookupNameInfo(),
RequiresADL, TemplateArgs,
R.begin(), R.end());
return ULE;
}
// We actually only call this from template instantiation.
ExprResult
Sema::BuildQualifiedTemplateIdExpr(CXXScopeSpec &SS,
SourceLocation TemplateKWLoc,
const DeclarationNameInfo &NameInfo,
const TemplateArgumentListInfo *TemplateArgs) {
assert(TemplateArgs || TemplateKWLoc.isValid());
DeclContext *DC;
if (!(DC = computeDeclContext(SS, false)) ||
DC->isDependentContext() ||
RequireCompleteDeclContext(SS, DC))
return BuildDependentDeclRefExpr(SS, TemplateKWLoc, NameInfo, TemplateArgs);
bool MemberOfUnknownSpecialization;
LookupResult R(*this, NameInfo, LookupOrdinaryName);
if (LookupTemplateName(R, (Scope *)nullptr, SS, QualType(),
/*Entering*/false, MemberOfUnknownSpecialization,
TemplateKWLoc))
return ExprError();
if (R.isAmbiguous())
return ExprError();
if (R.empty()) {
Diag(NameInfo.getLoc(), diag::err_no_member)
<< NameInfo.getName() << DC << SS.getRange();
return ExprError();
}
if (ClassTemplateDecl *Temp = R.getAsSingle<ClassTemplateDecl>()) {
Diag(NameInfo.getLoc(), diag::err_template_kw_refers_to_class_template)
<< SS.getScopeRep()
<< NameInfo.getName().getAsString() << SS.getRange();
Diag(Temp->getLocation(), diag::note_referenced_class_template);
return ExprError();
}
return BuildTemplateIdExpr(SS, TemplateKWLoc, R, /*ADL*/ false, TemplateArgs);
}
/// Form a template name from a name that is syntactically required to name a
/// template, either due to use of the 'template' keyword or because a name in
/// this syntactic context is assumed to name a template (C++ [temp.names]p2-4).
///
/// This action forms a template name given the name of the template and its
/// optional scope specifier. This is used when the 'template' keyword is used
/// or when the parsing context unambiguously treats a following '<' as
/// introducing a template argument list. Note that this may produce a
/// non-dependent template name if we can perform the lookup now and identify
/// the named template.
///
/// For example, given "x.MetaFun::template apply", the scope specifier
/// \p SS will be "MetaFun::", \p TemplateKWLoc contains the location
/// of the "template" keyword, and "apply" is the \p Name.
TemplateNameKind Sema::ActOnTemplateName(Scope *S,
CXXScopeSpec &SS,
SourceLocation TemplateKWLoc,
const UnqualifiedId &Name,
ParsedType ObjectType,
bool EnteringContext,
TemplateTy &Result,
bool AllowInjectedClassName) {
if (TemplateKWLoc.isValid() && S && !S->getTemplateParamParent())
Diag(TemplateKWLoc,
getLangOpts().CPlusPlus11 ?
diag::warn_cxx98_compat_template_outside_of_template :
diag::ext_template_outside_of_template)
<< FixItHint::CreateRemoval(TemplateKWLoc);
if (SS.isInvalid())
return TNK_Non_template;
// Figure out where isTemplateName is going to look.
DeclContext *LookupCtx = nullptr;
if (SS.isNotEmpty())
LookupCtx = computeDeclContext(SS, EnteringContext);
else if (ObjectType)
LookupCtx = computeDeclContext(GetTypeFromParser(ObjectType));
// C++0x [temp.names]p5:
// If a name prefixed by the keyword template is not the name of
// a template, the program is ill-formed. [Note: the keyword
// template may not be applied to non-template members of class
// templates. -end note ] [ Note: as is the case with the
// typename prefix, the template prefix is allowed in cases
// where it is not strictly necessary; i.e., when the
// nested-name-specifier or the expression on the left of the ->
// or . is not dependent on a template-parameter, or the use
// does not appear in the scope of a template. -end note]
//
// Note: C++03 was more strict here, because it banned the use of
// the "template" keyword prior to a template-name that was not a
// dependent name. C++ DR468 relaxed this requirement (the
// "template" keyword is now permitted). We follow the C++0x
// rules, even in C++03 mode with a warning, retroactively applying the DR.
bool MemberOfUnknownSpecialization;
TemplateNameKind TNK = isTemplateName(S, SS, TemplateKWLoc.isValid(), Name,
ObjectType, EnteringContext, Result,
MemberOfUnknownSpecialization);
if (TNK != TNK_Non_template) {
// We resolved this to a (non-dependent) template name. Return it.
auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(LookupCtx);
if (!AllowInjectedClassName && SS.isNotEmpty() && LookupRD &&
Name.getKind() == UnqualifiedIdKind::IK_Identifier &&
Name.Identifier && LookupRD->getIdentifier() == Name.Identifier) {
// C++14 [class.qual]p2:
// In a lookup in which function names are not ignored and the
// nested-name-specifier nominates a class C, if the name specified
// [...] is the injected-class-name of C, [...] the name is instead
// considered to name the constructor
//
// We don't get here if naming the constructor would be valid, so we
// just reject immediately and recover by treating the
// injected-class-name as naming the template.
Diag(Name.getBeginLoc(),
diag::ext_out_of_line_qualified_id_type_names_constructor)
<< Name.Identifier
<< 0 /*injected-class-name used as template name*/
<< TemplateKWLoc.isValid();
}
return TNK;
}
if (!MemberOfUnknownSpecialization) {
// Didn't find a template name, and the lookup wasn't dependent.
// Do the lookup again to determine if this is a "nothing found" case or
// a "not a template" case. FIXME: Refactor isTemplateName so we don't
// need to do this.
DeclarationNameInfo DNI = GetNameFromUnqualifiedId(Name);
LookupResult R(*this, DNI.getName(), Name.getBeginLoc(),
LookupOrdinaryName);
bool MOUS;
// Tell LookupTemplateName that we require a template so that it diagnoses
// cases where it finds a non-template.
RequiredTemplateKind RTK = TemplateKWLoc.isValid()
? RequiredTemplateKind(TemplateKWLoc)
: TemplateNameIsRequired;
if (!LookupTemplateName(R, S, SS, ObjectType.get(), EnteringContext, MOUS,
RTK, nullptr, /*AllowTypoCorrection=*/false) &&
!R.isAmbiguous()) {
if (LookupCtx)
Diag(Name.getBeginLoc(), diag::err_no_member)
<< DNI.getName() << LookupCtx << SS.getRange();
else
Diag(Name.getBeginLoc(), diag::err_undeclared_use)
<< DNI.getName() << SS.getRange();
}
return TNK_Non_template;
}
NestedNameSpecifier *Qualifier = SS.getScopeRep();
switch (Name.getKind()) {
case UnqualifiedIdKind::IK_Identifier:
Result = TemplateTy::make(
Context.getDependentTemplateName(Qualifier, Name.Identifier));
return TNK_Dependent_template_name;
case UnqualifiedIdKind::IK_OperatorFunctionId:
Result = TemplateTy::make(Context.getDependentTemplateName(
Qualifier, Name.OperatorFunctionId.Operator));
return TNK_Function_template;
case UnqualifiedIdKind::IK_LiteralOperatorId:
// This is a kind of template name, but can never occur in a dependent
// scope (literal operators can only be declared at namespace scope).
break;
default:
break;
}
// This name cannot possibly name a dependent template. Diagnose this now
// rather than building a dependent template name that can never be valid.
Diag(Name.getBeginLoc(),
diag::err_template_kw_refers_to_dependent_non_template)
<< GetNameFromUnqualifiedId(Name).getName() << Name.getSourceRange()
<< TemplateKWLoc.isValid() << TemplateKWLoc;
return TNK_Non_template;
}
bool Sema::CheckTemplateTypeArgument(TemplateTypeParmDecl *Param,
TemplateArgumentLoc &AL,
SmallVectorImpl<TemplateArgument> &Converted) {
const TemplateArgument &Arg = AL.getArgument();
QualType ArgType;
TypeSourceInfo *TSI = nullptr;
// Check template type parameter.
switch(Arg.getKind()) {
case TemplateArgument::Type:
// C++ [temp.arg.type]p1:
// A template-argument for a template-parameter which is a
// type shall be a type-id.
ArgType = Arg.getAsType();
TSI = AL.getTypeSourceInfo();
break;
case TemplateArgument::Template:
case TemplateArgument::TemplateExpansion: {
// We have a template type parameter but the template argument
// is a template without any arguments.
SourceRange SR = AL.getSourceRange();
TemplateName Name = Arg.getAsTemplateOrTemplatePattern();
diagnoseMissingTemplateArguments(Name, SR.getEnd());
return true;
}
case TemplateArgument::Expression: {
// We have a template type parameter but the template argument is an
// expression; see if maybe it is missing the "typename" keyword.
CXXScopeSpec SS;
DeclarationNameInfo NameInfo;
if (DependentScopeDeclRefExpr *ArgExpr =
dyn_cast<DependentScopeDeclRefExpr>(Arg.getAsExpr())) {
SS.Adopt(ArgExpr->getQualifierLoc());
NameInfo = ArgExpr->getNameInfo();
} else if (CXXDependentScopeMemberExpr *ArgExpr =
dyn_cast<CXXDependentScopeMemberExpr>(Arg.getAsExpr())) {
if (ArgExpr->isImplicitAccess()) {
SS.Adopt(ArgExpr->getQualifierLoc());
NameInfo = ArgExpr->getMemberNameInfo();
}
}
if (auto *II = NameInfo.getName().getAsIdentifierInfo()) {
LookupResult Result(*this, NameInfo, LookupOrdinaryName);
LookupParsedName(Result, CurScope, &SS);
if (Result.getAsSingle<TypeDecl>() ||
Result.getResultKind() ==
LookupResult::NotFoundInCurrentInstantiation) {
assert(SS.getScopeRep() && "dependent scope expr must has a scope!");
// Suggest that the user add 'typename' before the NNS.
SourceLocation Loc = AL.getSourceRange().getBegin();
Diag(Loc, getLangOpts().MSVCCompat
? diag::ext_ms_template_type_arg_missing_typename
: diag::err_template_arg_must_be_type_suggest)
<< FixItHint::CreateInsertion(Loc, "typename ");
Diag(Param->getLocation(), diag::note_template_param_here);
// Recover by synthesizing a type using the location information that we
// already have.
ArgType =
Context.getDependentNameType(ETK_Typename, SS.getScopeRep(), II);
TypeLocBuilder TLB;
DependentNameTypeLoc TL = TLB.push<DependentNameTypeLoc>(ArgType);
TL.setElaboratedKeywordLoc(SourceLocation(/*synthesized*/));
TL.setQualifierLoc(SS.getWithLocInContext(Context));
TL.setNameLoc(NameInfo.getLoc());
TSI = TLB.getTypeSourceInfo(Context, ArgType);
// Overwrite our input TemplateArgumentLoc so that we can recover
// properly.
AL = TemplateArgumentLoc(TemplateArgument(ArgType),
TemplateArgumentLocInfo(TSI));
break;
}
}
// fallthrough
LLVM_FALLTHROUGH;
}
default: {
// We have a template type parameter but the template argument
// is not a type.
SourceRange SR = AL.getSourceRange();
Diag(SR.getBegin(), diag::err_template_arg_must_be_type) << SR;
Diag(Param->getLocation(), diag::note_template_param_here);
return true;
}
}
if (CheckTemplateArgument(TSI))
return true;
// Add the converted template type argument.
ArgType = Context.getCanonicalType(ArgType);
// Objective-C ARC:
// If an explicitly-specified template argument type is a lifetime type
// with no lifetime qualifier, the __strong lifetime qualifier is inferred.
if (getLangOpts().ObjCAutoRefCount &&
ArgType->isObjCLifetimeType() &&
!ArgType.getObjCLifetime()) {
Qualifiers Qs;
Qs.setObjCLifetime(Qualifiers::OCL_Strong);
ArgType = Context.getQualifiedType(ArgType, Qs);
}
Converted.push_back(TemplateArgument(ArgType));
return false;
}
/// Substitute template arguments into the default template argument for
/// the given template type parameter.
///
/// \param SemaRef the semantic analysis object for which we are performing
/// the substitution.
///
/// \param Template the template that we are synthesizing template arguments
/// for.
///
/// \param TemplateLoc the location of the template name that started the
/// template-id we are checking.
///
/// \param RAngleLoc the location of the right angle bracket ('>') that
/// terminates the template-id.
///
/// \param Param the template template parameter whose default we are
/// substituting into.
///
/// \param Converted the list of template arguments provided for template
/// parameters that precede \p Param in the template parameter list.
/// \returns the substituted template argument, or NULL if an error occurred.
static TypeSourceInfo *
SubstDefaultTemplateArgument(Sema &SemaRef,
TemplateDecl *Template,
SourceLocation TemplateLoc,
SourceLocation RAngleLoc,
TemplateTypeParmDecl *Param,
SmallVectorImpl<TemplateArgument> &Converted) {
TypeSourceInfo *ArgType = Param->getDefaultArgumentInfo();
// If the argument type is dependent, instantiate it now based
// on the previously-computed template arguments.
if (ArgType->getType()->isInstantiationDependentType()) {
Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc,
Param, Template, Converted,
SourceRange(TemplateLoc, RAngleLoc));
if (Inst.isInvalid())
return nullptr;
TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
// Only substitute for the innermost template argument list.
MultiLevelTemplateArgumentList TemplateArgLists;
TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
TemplateArgLists.addOuterTemplateArguments(None);
bool ForLambdaCallOperator = false;
if (const auto *Rec = dyn_cast<CXXRecordDecl>(Template->getDeclContext()))
ForLambdaCallOperator = Rec->isLambda();
Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext(),
!ForLambdaCallOperator);
ArgType =
SemaRef.SubstType(ArgType, TemplateArgLists,
Param->getDefaultArgumentLoc(), Param->getDeclName());
}
return ArgType;
}
/// Substitute template arguments into the default template argument for
/// the given non-type template parameter.
///
/// \param SemaRef the semantic analysis object for which we are performing
/// the substitution.
///
/// \param Template the template that we are synthesizing template arguments
/// for.
///
/// \param TemplateLoc the location of the template name that started the
/// template-id we are checking.
///
/// \param RAngleLoc the location of the right angle bracket ('>') that
/// terminates the template-id.
///
/// \param Param the non-type template parameter whose default we are
/// substituting into.
///
/// \param Converted the list of template arguments provided for template
/// parameters that precede \p Param in the template parameter list.
///
/// \returns the substituted template argument, or NULL if an error occurred.
static ExprResult
SubstDefaultTemplateArgument(Sema &SemaRef,
TemplateDecl *Template,
SourceLocation TemplateLoc,
SourceLocation RAngleLoc,
NonTypeTemplateParmDecl *Param,
SmallVectorImpl<TemplateArgument> &Converted) {
Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc,
Param, Template, Converted,
SourceRange(TemplateLoc, RAngleLoc));
if (Inst.isInvalid())
return ExprError();
TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
// Only substitute for the innermost template argument list.
MultiLevelTemplateArgumentList TemplateArgLists;
TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
TemplateArgLists.addOuterTemplateArguments(None);
Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
EnterExpressionEvaluationContext ConstantEvaluated(
SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);
return SemaRef.SubstExpr(Param->getDefaultArgument(), TemplateArgLists);
}
/// Substitute template arguments into the default template argument for
/// the given template template parameter.
///
/// \param SemaRef the semantic analysis object for which we are performing
/// the substitution.
///
/// \param Template the template that we are synthesizing template arguments
/// for.
///
/// \param TemplateLoc the location of the template name that started the
/// template-id we are checking.
///
/// \param RAngleLoc the location of the right angle bracket ('>') that
/// terminates the template-id.
///
/// \param Param the template template parameter whose default we are
/// substituting into.
///
/// \param Converted the list of template arguments provided for template
/// parameters that precede \p Param in the template parameter list.
///
/// \param QualifierLoc Will be set to the nested-name-specifier (with
/// source-location information) that precedes the template name.
///
/// \returns the substituted template argument, or NULL if an error occurred.
static TemplateName
SubstDefaultTemplateArgument(Sema &SemaRef,
TemplateDecl *Template,
SourceLocation TemplateLoc,
SourceLocation RAngleLoc,
TemplateTemplateParmDecl *Param,
SmallVectorImpl<TemplateArgument> &Converted,
NestedNameSpecifierLoc &QualifierLoc) {
Sema::InstantiatingTemplate Inst(
SemaRef, TemplateLoc, TemplateParameter(Param), Template, Converted,
SourceRange(TemplateLoc, RAngleLoc));
if (Inst.isInvalid())
return TemplateName();
TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
// Only substitute for the innermost template argument list.
MultiLevelTemplateArgumentList TemplateArgLists;
TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
TemplateArgLists.addOuterTemplateArguments(None);
Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
// Substitute into the nested-name-specifier first,
QualifierLoc = Param->getDefaultArgument().getTemplateQualifierLoc();
if (QualifierLoc) {
QualifierLoc =
SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc, TemplateArgLists);
if (!QualifierLoc)
return TemplateName();
}
return SemaRef.SubstTemplateName(
QualifierLoc,
Param->getDefaultArgument().getArgument().getAsTemplate(),
Param->getDefaultArgument().getTemplateNameLoc(),
TemplateArgLists);
}
/// If the given template parameter has a default template
/// argument, substitute into that default template argument and
/// return the corresponding template argument.
TemplateArgumentLoc
Sema::SubstDefaultTemplateArgumentIfAvailable(TemplateDecl *Template,
SourceLocation TemplateLoc,
SourceLocation RAngleLoc,
Decl *Param,
SmallVectorImpl<TemplateArgument>
&Converted,
bool &HasDefaultArg) {
HasDefaultArg = false;
if (TemplateTypeParmDecl *TypeParm = dyn_cast<TemplateTypeParmDecl>(Param)) {
if (!hasVisibleDefaultArgument(TypeParm))
return TemplateArgumentLoc();
HasDefaultArg = true;
TypeSourceInfo *DI = SubstDefaultTemplateArgument(*this, Template,
TemplateLoc,
RAngleLoc,
TypeParm,
Converted);
if (DI)
return TemplateArgumentLoc(TemplateArgument(DI->getType()), DI);
return TemplateArgumentLoc();
}
if (NonTypeTemplateParmDecl *NonTypeParm
= dyn_cast<NonTypeTemplateParmDecl>(Param)) {
if (!hasVisibleDefaultArgument(NonTypeParm))
return TemplateArgumentLoc();
HasDefaultArg = true;
ExprResult Arg = SubstDefaultTemplateArgument(*this, Template,
TemplateLoc,
RAngleLoc,
NonTypeParm,
Converted);
if (Arg.isInvalid())
return TemplateArgumentLoc();
Expr *ArgE = Arg.getAs<Expr>();
return TemplateArgumentLoc(TemplateArgument(ArgE), ArgE);
}
TemplateTemplateParmDecl *TempTempParm
= cast<TemplateTemplateParmDecl>(Param);
if (!hasVisibleDefaultArgument(TempTempParm))
return TemplateArgumentLoc();
HasDefaultArg = true;
NestedNameSpecifierLoc QualifierLoc;
TemplateName TName = SubstDefaultTemplateArgument(*this, Template,
TemplateLoc,
RAngleLoc,
TempTempParm,
Converted,
QualifierLoc);
if (TName.isNull())
return TemplateArgumentLoc();
return TemplateArgumentLoc(
Context, TemplateArgument(TName),
TempTempParm->getDefaultArgument().getTemplateQualifierLoc(),
TempTempParm->getDefaultArgument().getTemplateNameLoc());
}
/// Convert a template-argument that we parsed as a type into a template, if
/// possible. C++ permits injected-class-names to perform dual service as
/// template template arguments and as template type arguments.
static TemplateArgumentLoc
convertTypeTemplateArgumentToTemplate(ASTContext &Context, TypeLoc TLoc) {
// Extract and step over any surrounding nested-name-specifier.
NestedNameSpecifierLoc QualLoc;
if (auto ETLoc = TLoc.getAs<ElaboratedTypeLoc>()) {
if (ETLoc.getTypePtr()->getKeyword() != ETK_None)
return TemplateArgumentLoc();
QualLoc = ETLoc.getQualifierLoc();
TLoc = ETLoc.getNamedTypeLoc();
}
// If this type was written as an injected-class-name, it can be used as a
// template template argument.
if (auto InjLoc = TLoc.getAs<InjectedClassNameTypeLoc>())
return TemplateArgumentLoc(Context, InjLoc.getTypePtr()->getTemplateName(),
QualLoc, InjLoc.getNameLoc());
// If this type was written as an injected-class-name, it may have been
// converted to a RecordType during instantiation. If the RecordType is
// *not* wrapped in a TemplateSpecializationType and denotes a class
// template specialization, it must have come from an injected-class-name.
if (auto RecLoc = TLoc.getAs<RecordTypeLoc>())
if (auto *CTSD =
dyn_cast<ClassTemplateSpecializationDecl>(RecLoc.getDecl()))
return TemplateArgumentLoc(Context,
TemplateName(CTSD->getSpecializedTemplate()),
QualLoc, RecLoc.getNameLoc());
return TemplateArgumentLoc();
}
/// Check that the given template argument corresponds to the given
/// template parameter.
///
/// \param Param The template parameter against which the argument will be
/// checked.
///
/// \param Arg The template argument, which may be updated due to conversions.
///
/// \param Template The template in which the template argument resides.
///
/// \param TemplateLoc The location of the template name for the template
/// whose argument list we're matching.
///
/// \param RAngleLoc The location of the right angle bracket ('>') that closes
/// the template argument list.
///
/// \param ArgumentPackIndex The index into the argument pack where this
/// argument will be placed. Only valid if the parameter is a parameter pack.
///
/// \param Converted The checked, converted argument will be added to the
/// end of this small vector.
///
/// \param CTAK Describes how we arrived at this particular template argument:
/// explicitly written, deduced, etc.
///
/// \returns true on error, false otherwise.
bool Sema::CheckTemplateArgument(NamedDecl *Param,
TemplateArgumentLoc &Arg,
NamedDecl *Template,
SourceLocation TemplateLoc,
SourceLocation RAngleLoc,
unsigned ArgumentPackIndex,
SmallVectorImpl<TemplateArgument> &Converted,
CheckTemplateArgumentKind CTAK) {
// Check template type parameters.
if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param))
return CheckTemplateTypeArgument(TTP, Arg, Converted);
// Check non-type template parameters.
if (NonTypeTemplateParmDecl *NTTP =dyn_cast<NonTypeTemplateParmDecl>(Param)) {
// Do substitution on the type of the non-type template parameter
// with the template arguments we've seen thus far. But if the
// template has a dependent context then we cannot substitute yet.
QualType NTTPType = NTTP->getType();
if (NTTP->isParameterPack() && NTTP->isExpandedParameterPack())
NTTPType = NTTP->getExpansionType(ArgumentPackIndex);
if (NTTPType->isInstantiationDependentType() &&
!isa<TemplateTemplateParmDecl>(Template) &&
!Template->getDeclContext()->isDependentContext()) {
// Do substitution on the type of the non-type template parameter.
InstantiatingTemplate Inst(*this, TemplateLoc, Template,
NTTP, Converted,
SourceRange(TemplateLoc, RAngleLoc));
if (Inst.isInvalid())
return true;
TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack,
Converted);
// If the parameter is a pack expansion, expand this slice of the pack.
if (auto *PET = NTTPType->getAs<PackExpansionType>()) {
Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this,
ArgumentPackIndex);
NTTPType = SubstType(PET->getPattern(),
MultiLevelTemplateArgumentList(TemplateArgs),
NTTP->getLocation(),
NTTP->getDeclName());
} else {
NTTPType = SubstType(NTTPType,
MultiLevelTemplateArgumentList(TemplateArgs),
NTTP->getLocation(),
NTTP->getDeclName());
}
// If that worked, check the non-type template parameter type
// for validity.
if (!NTTPType.isNull())
NTTPType = CheckNonTypeTemplateParameterType(NTTPType,
NTTP->getLocation());
if (NTTPType.isNull())
return true;
}
switch (Arg.getArgument().getKind()) {
case TemplateArgument::Null:
llvm_unreachable("Should never see a NULL template argument here");
case TemplateArgument::Expression: {
TemplateArgument Result;
unsigned CurSFINAEErrors = NumSFINAEErrors;
ExprResult Res =
CheckTemplateArgument(NTTP, NTTPType, Arg.getArgument().getAsExpr(),
Result, CTAK);
if (Res.isInvalid())
return true;
// If the current template argument causes an error, give up now.
if (CurSFINAEErrors < NumSFINAEErrors)
return true;
// If the resulting expression is new, then use it in place of the
// old expression in the template argument.
if (Res.get() != Arg.getArgument().getAsExpr()) {
TemplateArgument TA(Res.get());
Arg = TemplateArgumentLoc(TA, Res.get());
}
Converted.push_back(Result);
break;
}
case TemplateArgument::Declaration:
case TemplateArgument::Integral:
case TemplateArgument::NullPtr:
// We've already checked this template argument, so just copy
// it to the list of converted arguments.
Converted.push_back(Arg.getArgument());
break;
case TemplateArgument::Template:
case TemplateArgument::TemplateExpansion:
// We were given a template template argument. It may not be ill-formed;
// see below.
if (DependentTemplateName *DTN
= Arg.getArgument().getAsTemplateOrTemplatePattern()
.getAsDependentTemplateName()) {
// We have a template argument such as \c T::template X, which we
// parsed as a template template argument. However, since we now
// know that we need a non-type template argument, convert this
// template name into an expression.
DeclarationNameInfo NameInfo(DTN->getIdentifier(),
Arg.getTemplateNameLoc());
CXXScopeSpec SS;
SS.Adopt(Arg.getTemplateQualifierLoc());
// FIXME: the template-template arg was a DependentTemplateName,
// so it was provided with a template keyword. However, its source
// location is not stored in the template argument structure.
SourceLocation TemplateKWLoc;
ExprResult E = DependentScopeDeclRefExpr::Create(
Context, SS.getWithLocInContext(Context), TemplateKWLoc, NameInfo,
nullptr);
// If we parsed the template argument as a pack expansion, create a
// pack expansion expression.
if (Arg.getArgument().getKind() == TemplateArgument::TemplateExpansion){
E = ActOnPackExpansion(E.get(), Arg.getTemplateEllipsisLoc());
if (E.isInvalid())
return true;
}
TemplateArgument Result;
E = CheckTemplateArgument(NTTP, NTTPType, E.get(), Result);
if (E.isInvalid())
return true;
Converted.push_back(Result);
break;
}
// We have a template argument that actually does refer to a class
// template, alias template, or template template parameter, and
// therefore cannot be a non-type template argument.
Diag(Arg.getLocation(), diag::err_template_arg_must_be_expr)
<< Arg.getSourceRange();
Diag(Param->getLocation(), diag::note_template_param_here);
return true;
case TemplateArgument::Type: {
// We have a non-type template parameter but the template
// argument is a type.
// C++ [temp.arg]p2:
// In a template-argument, an ambiguity between a type-id and
// an expression is resolved to a type-id, regardless of the
// form of the corresponding template-parameter.
//
// We warn specifically about this case, since it can be rather
// confusing for users.
QualType T = Arg.getArgument().getAsType();
SourceRange SR = Arg.getSourceRange();
if (T->isFunctionType())
Diag(SR.getBegin(), diag::err_template_arg_nontype_ambig) << SR << T;
else
Diag(SR.getBegin(), diag::err_template_arg_must_be_expr) << SR;
Diag(Param->getLocation(), diag::note_template_param_here);
return true;
}
case TemplateArgument::Pack:
llvm_unreachable("Caller must expand template argument packs");
}
return false;
}
// Check template template parameters.
TemplateTemplateParmDecl *TempParm = cast<TemplateTemplateParmDecl>(Param);
TemplateParameterList *Params = TempParm->getTemplateParameters();
if (TempParm->isExpandedParameterPack())
Params = TempParm->getExpansionTemplateParameters(ArgumentPackIndex);
// Substitute into the template parameter list of the template
// template parameter, since previously-supplied template arguments
// may appear within the template template parameter.
//
// FIXME: Skip this if the parameters aren't instantiation-dependent.
{
// Set up a template instantiation context.
LocalInstantiationScope Scope(*this);
InstantiatingTemplate Inst(*this, TemplateLoc, Template,
TempParm, Converted,
SourceRange(TemplateLoc, RAngleLoc));
if (Inst.isInvalid())
return true;
TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
Params = SubstTemplateParams(Params, CurContext,
MultiLevelTemplateArgumentList(TemplateArgs));
if (!Params)
return true;
}
// C++1z [temp.local]p1: (DR1004)
// When [the injected-class-name] is used [...] as a template-argument for
// a template template-parameter [...] it refers to the class template
// itself.
if (Arg.getArgument().getKind() == TemplateArgument::Type) {
TemplateArgumentLoc ConvertedArg = convertTypeTemplateArgumentToTemplate(
Context, Arg.getTypeSourceInfo()->getTypeLoc());
if (!ConvertedArg.getArgument().isNull())
Arg = ConvertedArg;
}
switch (Arg.getArgument().getKind()) {
case TemplateArgument::Null:
llvm_unreachable("Should never see a NULL template argument here");
case TemplateArgument::Template:
case TemplateArgument::TemplateExpansion:
if (CheckTemplateTemplateArgument(TempParm, Params, Arg))
return true;
Converted.push_back(Arg.getArgument());
break;
case TemplateArgument::Expression:
case TemplateArgument::Type:
// We have a template template parameter but the template
// argument does not refer to a template.
Diag(Arg.getLocation(), diag::err_template_arg_must_be_template)
<< getLangOpts().CPlusPlus11;
return true;
case TemplateArgument::Declaration:
llvm_unreachable("Declaration argument with template template parameter");
case TemplateArgument::Integral:
llvm_unreachable("Integral argument with template template parameter");
case TemplateArgument::NullPtr:
llvm_unreachable("Null pointer argument with template template parameter");
case TemplateArgument::Pack:
llvm_unreachable("Caller must expand template argument packs");
}
return false;
}
/// Diagnose a missing template argument.
template<typename TemplateParmDecl>
static bool diagnoseMissingArgument(Sema &S, SourceLocation Loc,
TemplateDecl *TD,
const TemplateParmDecl *D,
TemplateArgumentListInfo &Args) {
// Dig out the most recent declaration of the template parameter; there may be
// declarations of the template that are more recent than TD.
D = cast<TemplateParmDecl>(cast<TemplateDecl>(TD->getMostRecentDecl())
->getTemplateParameters()
->getParam(D->getIndex()));
// If there's a default argument that's not visible, diagnose that we're
// missing a module import.
llvm::SmallVector<Module*, 8> Modules;
if (D->hasDefaultArgument() && !S.hasVisibleDefaultArgument(D, &Modules)) {
S.diagnoseMissingImport(Loc, cast<NamedDecl>(TD),
D->getDefaultArgumentLoc(), Modules,
Sema::MissingImportKind::DefaultArgument,
/*Recover*/true);
return true;
}
// FIXME: If there's a more recent default argument that *is* visible,
// diagnose that it was declared too late.
TemplateParameterList *Params = TD->getTemplateParameters();
S.Diag(Loc, diag::err_template_arg_list_different_arity)
<< /*not enough args*/0
<< (int)S.getTemplateNameKindForDiagnostics(TemplateName(TD))
<< TD;
S.Diag(TD->getLocation(), diag::note_template_decl_here)
<< Params->getSourceRange();
return true;
}
/// Check that the given template argument list is well-formed
/// for specializing the given template.
bool Sema::CheckTemplateArgumentList(
TemplateDecl *Template, SourceLocation TemplateLoc,
TemplateArgumentListInfo &TemplateArgs, bool PartialTemplateArgs,
SmallVectorImpl<TemplateArgument> &Converted,
bool UpdateArgsWithConversions, bool *ConstraintsNotSatisfied) {
if (ConstraintsNotSatisfied)
*ConstraintsNotSatisfied = false;
// Make a copy of the template arguments for processing. Only make the
// changes at the end when successful in matching the arguments to the
// template.
TemplateArgumentListInfo NewArgs = TemplateArgs;
// Make sure we get the template parameter list from the most
// recent declaration, since that is the only one that is guaranteed to
// have all the default template argument information.
TemplateParameterList *Params =
cast<TemplateDecl>(Template->getMostRecentDecl())
->getTemplateParameters();
SourceLocation RAngleLoc = NewArgs.getRAngleLoc();
// C++ [temp.arg]p1:
// [...] The type and form of each template-argument specified in
// a template-id shall match the type and form specified for the
// corresponding parameter declared by the template in its
// template-parameter-list.
bool isTemplateTemplateParameter = isa<TemplateTemplateParmDecl>(Template);
SmallVector<TemplateArgument, 2> ArgumentPack;
unsigned ArgIdx = 0, NumArgs = NewArgs.size();
LocalInstantiationScope InstScope(*this, true);
for (TemplateParameterList::iterator Param = Params->begin(),
ParamEnd = Params->end();
Param != ParamEnd; /* increment in loop */) {
// If we have an expanded parameter pack, make sure we don't have too
// many arguments.
if (Optional<unsigned> Expansions = getExpandedPackSize(*Param)) {
if (*Expansions == ArgumentPack.size()) {
// We're done with this parameter pack. Pack up its arguments and add
// them to the list.
Converted.push_back(
TemplateArgument::CreatePackCopy(Context, ArgumentPack));
ArgumentPack.clear();
// This argument is assigned to the next parameter.
++Param;
continue;
} else if (ArgIdx == NumArgs && !PartialTemplateArgs) {
// Not enough arguments for this parameter pack.
Diag(TemplateLoc, diag::err_template_arg_list_different_arity)
<< /*not enough args*/0
<< (int)getTemplateNameKindForDiagnostics(TemplateName(Template))
<< Template;
Diag(Template->getLocation(), diag::note_template_decl_here)
<< Params->getSourceRange();
return true;
}
}
if (ArgIdx < NumArgs) {
// Check the template argument we were given.
if (CheckTemplateArgument(*Param, NewArgs[ArgIdx], Template,
TemplateLoc, RAngleLoc,
ArgumentPack.size(), Converted))
return true;
bool PackExpansionIntoNonPack =
NewArgs[ArgIdx].getArgument().isPackExpansion() &&
(!(*Param)->isTemplateParameterPack() || getExpandedPackSize(*Param));
if (PackExpansionIntoNonPack && (isa<TypeAliasTemplateDecl>(Template) ||
isa<ConceptDecl>(Template))) {
// Core issue 1430: we have a pack expansion as an argument to an
// alias template, and it's not part of a parameter pack. This
// can't be canonicalized, so reject it now.
// As for concepts - we cannot normalize constraints where this
// situation exists.
Diag(NewArgs[ArgIdx].getLocation(),
diag::err_template_expansion_into_fixed_list)
<< (isa<ConceptDecl>(Template) ? 1 : 0)
<< NewArgs[ArgIdx].getSourceRange();
Diag((*Param)->getLocation(), diag::note_template_param_here);
return true;
}
// We're now done with this argument.
++ArgIdx;
if ((*Param)->isTemplateParameterPack()) {
// The template parameter was a template parameter pack, so take the
// deduced argument and place it on the argument pack. Note that we
// stay on the same template parameter so that we can deduce more
// arguments.
ArgumentPack.push_back(Converted.pop_back_val());
} else {
// Move to the next template parameter.
++Param;
}
// If we just saw a pack expansion into a non-pack, then directly convert
// the remaining arguments, because we don't know what parameters they'll
// match up with.
if (PackExpansionIntoNonPack) {
if (!ArgumentPack.empty()) {
// If we were part way through filling in an expanded parameter pack,
// fall back to just producing individual arguments.
Converted.insert(Converted.end(),
ArgumentPack.begin(), ArgumentPack.end());
ArgumentPack.clear();
}
while (ArgIdx < NumArgs) {
Converted.push_back(NewArgs[ArgIdx].getArgument());
++ArgIdx;
}
return false;
}
continue;
}
// If we're checking a partial template argument list, we're done.
if (PartialTemplateArgs) {
if ((*Param)->isTemplateParameterPack() && !ArgumentPack.empty())
Converted.push_back(
TemplateArgument::CreatePackCopy(Context, ArgumentPack));
return false;
}
// If we have a template parameter pack with no more corresponding
// arguments, just break out now and we'll fill in the argument pack below.
if ((*Param)->isTemplateParameterPack()) {
assert(!getExpandedPackSize(*Param) &&
"Should have dealt with this already");
// A non-expanded parameter pack before the end of the parameter list
// only occurs for an ill-formed template parameter list, unless we've
// got a partial argument list for a function template, so just bail out.
if (Param + 1 != ParamEnd)
return true;
Converted.push_back(
TemplateArgument::CreatePackCopy(Context, ArgumentPack));
ArgumentPack.clear();
++Param;
continue;
}
// Check whether we have a default argument.
TemplateArgumentLoc Arg;
// Retrieve the default template argument from the template
// parameter. For each kind of template parameter, we substitute the
// template arguments provided thus far and any "outer" template arguments
// (when the template parameter was part of a nested template) into
// the default argument.
if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*Param)) {
if (!hasVisibleDefaultArgument(TTP))
return diagnoseMissingArgument(*this, TemplateLoc, Template, TTP,
NewArgs);
TypeSourceInfo *ArgType = SubstDefaultTemplateArgument(*this,
Template,
TemplateLoc,
RAngleLoc,
TTP,
Converted);
if (!ArgType)
return true;
Arg = TemplateArgumentLoc(TemplateArgument(ArgType->getType()),
ArgType);
} else if (NonTypeTemplateParmDecl *NTTP
= dyn_cast<NonTypeTemplateParmDecl>(*Param)) {
if (!hasVisibleDefaultArgument(NTTP))
return diagnoseMissingArgument(*this, TemplateLoc, Template, NTTP,
NewArgs);
ExprResult E = SubstDefaultTemplateArgument(*this, Template,
TemplateLoc,
RAngleLoc,
NTTP,
Converted);
if (E.isInvalid())
return true;
Expr *Ex = E.getAs<Expr>();
Arg = TemplateArgumentLoc(TemplateArgument(Ex), Ex);
} else {
TemplateTemplateParmDecl *TempParm
= cast<TemplateTemplateParmDecl>(*Param);
if (!hasVisibleDefaultArgument(TempParm))
return diagnoseMissingArgument(*this, TemplateLoc, Template, TempParm,
NewArgs);
NestedNameSpecifierLoc QualifierLoc;
TemplateName Name = SubstDefaultTemplateArgument(*this, Template,
TemplateLoc,
RAngleLoc,
TempParm,
Converted,
QualifierLoc);
if (Name.isNull())
return true;
Arg = TemplateArgumentLoc(
Context, TemplateArgument(Name), QualifierLoc,
TempParm->getDefaultArgument().getTemplateNameLoc());
}
// Introduce an instantiation record that describes where we are using
// the default template argument. We're not actually instantiating a
// template here, we just create this object to put a note into the
// context stack.
InstantiatingTemplate Inst(*this, RAngleLoc, Template, *Param, Converted,
SourceRange(TemplateLoc, RAngleLoc));
if (Inst.isInvalid())
return true;
// Check the default template argument.
if (CheckTemplateArgument(*Param, Arg, Template, TemplateLoc,
RAngleLoc, 0, Converted))
return true;
// Core issue 150 (assumed resolution): if this is a template template
// parameter, keep track of the default template arguments from the
// template definition.
if (isTemplateTemplateParameter)
NewArgs.addArgument(Arg);
// Move to the next template parameter and argument.
++Param;
++ArgIdx;
}
// If we're performing a partial argument substitution, allow any trailing
// pack expansions; they might be empty. This can happen even if
// PartialTemplateArgs is false (the list of arguments is complete but
// still dependent).
if (ArgIdx < NumArgs && CurrentInstantiationScope &&
CurrentInstantiationScope->getPartiallySubstitutedPack()) {
while (ArgIdx < NumArgs && NewArgs[ArgIdx].getArgument().isPackExpansion())
Converted.push_back(NewArgs[ArgIdx++].getArgument());
}
// If we have any leftover arguments, then there were too many arguments.
// Complain and fail.
if (ArgIdx < NumArgs) {
Diag(TemplateLoc, diag::err_template_arg_list_different_arity)
<< /*too many args*/1
<< (int)getTemplateNameKindForDiagnostics(TemplateName(Template))
<< Template
<< SourceRange(NewArgs[ArgIdx].getLocation(), NewArgs.getRAngleLoc());
Diag(Template->getLocation(), diag::note_template_decl_here)
<< Params->getSourceRange();
return true;
}
// No problems found with the new argument list, propagate changes back
// to caller.
if (UpdateArgsWithConversions)
TemplateArgs = std::move(NewArgs);
if (!PartialTemplateArgs &&
EnsureTemplateArgumentListConstraints(
Template, Converted, SourceRange(TemplateLoc,
TemplateArgs.getRAngleLoc()))) {
if (ConstraintsNotSatisfied)
*ConstraintsNotSatisfied = true;
return true;
}
return false;
}
namespace {
class UnnamedLocalNoLinkageFinder
: public TypeVisitor<UnnamedLocalNoLinkageFinder, bool>
{
Sema &S;
SourceRange SR;
typedef TypeVisitor<UnnamedLocalNoLinkageFinder, bool> inherited;
public:
UnnamedLocalNoLinkageFinder(Sema &S, SourceRange SR) : S(S), SR(SR) { }
bool Visit(QualType T) {
return T.isNull() ? false : inherited::Visit(T.getTypePtr());
}
#define TYPE(Class, Parent) \
bool Visit##Class##Type(const Class##Type *);
#define ABSTRACT_TYPE(Class, Parent) \
bool Visit##Class##Type(const Class##Type *) { return false; }
#define NON_CANONICAL_TYPE(Class, Parent) \
bool Visit##Class##Type(const Class##Type *) { return false; }
#include "clang/AST/TypeNodes.inc"
bool VisitTagDecl(const TagDecl *Tag);
bool VisitNestedNameSpecifier(NestedNameSpecifier *NNS);
};
} // end anonymous namespace
bool UnnamedLocalNoLinkageFinder::VisitBuiltinType(const BuiltinType*) {
return false;
}
bool UnnamedLocalNoLinkageFinder::VisitComplexType(const ComplexType* T) {
return Visit(T->getElementType());
}
bool UnnamedLocalNoLinkageFinder::VisitPointerType(const PointerType* T) {
return Visit(T->getPointeeType());
}
bool UnnamedLocalNoLinkageFinder::VisitBlockPointerType(
const BlockPointerType* T) {
return Visit(T->getPointeeType());
}
bool UnnamedLocalNoLinkageFinder::VisitLValueReferenceType(
const LValueReferenceType* T) {
return Visit(T->getPointeeType());
}
bool UnnamedLocalNoLinkageFinder::VisitRValueReferenceType(
const RValueReferenceType* T) {
return Visit(T->getPointeeType());
}
bool UnnamedLocalNoLinkageFinder::VisitMemberPointerType(
const MemberPointerType* T) {
return Visit(T->getPointeeType()) || Visit(QualType(T->getClass(), 0));
}
bool UnnamedLocalNoLinkageFinder::VisitConstantArrayType(
const ConstantArrayType* T) {
return Visit(T->getElementType());
}
bool UnnamedLocalNoLinkageFinder::VisitIncompleteArrayType(
const IncompleteArrayType* T) {
return Visit(T->getElementType());
}
bool UnnamedLocalNoLinkageFinder::VisitVariableArrayType(
const VariableArrayType* T) {
return Visit(T->getElementType());
}
bool UnnamedLocalNoLinkageFinder::VisitDependentSizedArrayType(
const DependentSizedArrayType* T) {
return Visit(T->getElementType());
}
bool UnnamedLocalNoLinkageFinder::VisitDependentSizedExtVectorType(
const DependentSizedExtVectorType* T) {
return Visit(T->getElementType());
}
bool UnnamedLocalNoLinkageFinder::VisitDependentSizedMatrixType(
const DependentSizedMatrixType *T) {
return Visit(T->getElementType());
}
bool UnnamedLocalNoLinkageFinder::VisitDependentAddressSpaceType(
const DependentAddressSpaceType *T) {
return Visit(T->getPointeeType());
}
bool UnnamedLocalNoLinkageFinder::VisitVectorType(const VectorType* T) {
return Visit(T->getElementType());
}
bool UnnamedLocalNoLinkageFinder::VisitDependentVectorType(
const DependentVectorType *T) {
return Visit(T->getElementType());
}
bool UnnamedLocalNoLinkageFinder::VisitExtVectorType(const ExtVectorType* T) {
return Visit(T->getElementType());
}
bool UnnamedLocalNoLinkageFinder::VisitConstantMatrixType(
const ConstantMatrixType *T) {
return Visit(T->getElementType());
}
bool UnnamedLocalNoLinkageFinder::VisitFunctionProtoType(
const FunctionProtoType* T) {
for (const auto &A : T->param_types()) {
if (Visit(A))
return true;
}
return Visit(T->getReturnType());
}
bool UnnamedLocalNoLinkageFinder::VisitFunctionNoProtoType(
const FunctionNoProtoType* T) {
return Visit(T->getReturnType());
}
bool UnnamedLocalNoLinkageFinder::VisitUnresolvedUsingType(
const UnresolvedUsingType*) {
return false;
}
bool UnnamedLocalNoLinkageFinder::VisitTypeOfExprType(const TypeOfExprType*) {
return false;
}
bool UnnamedLocalNoLinkageFinder::VisitTypeOfType(const TypeOfType* T) {
return Visit(T->getUnderlyingType());
}
bool UnnamedLocalNoLinkageFinder::VisitDecltypeType(const DecltypeType*) {
return false;
}
bool UnnamedLocalNoLinkageFinder::VisitUnaryTransformType(
const UnaryTransformType*) {
return false;
}
bool UnnamedLocalNoLinkageFinder::VisitAutoType(const AutoType *T) {
return Visit(T->getDeducedType());
}
bool UnnamedLocalNoLinkageFinder::VisitDeducedTemplateSpecializationType(
const DeducedTemplateSpecializationType *T) {
return Visit(T->getDeducedType());
}
bool UnnamedLocalNoLinkageFinder::VisitRecordType(const RecordType* T) {
return VisitTagDecl(T->getDecl());
}
bool UnnamedLocalNoLinkageFinder::VisitEnumType(const EnumType* T) {
return VisitTagDecl(T->getDecl());
}
bool UnnamedLocalNoLinkageFinder::VisitTemplateTypeParmType(
const TemplateTypeParmType*) {
return false;
}
bool UnnamedLocalNoLinkageFinder::VisitSubstTemplateTypeParmPackType(
const SubstTemplateTypeParmPackType *) {
return false;
}
bool UnnamedLocalNoLinkageFinder::VisitTemplateSpecializationType(
const TemplateSpecializationType*) {
return false;
}
bool UnnamedLocalNoLinkageFinder::VisitInjectedClassNameType(
const InjectedClassNameType* T) {
return VisitTagDecl(T->getDecl());
}
bool UnnamedLocalNoLinkageFinder::VisitDependentNameType(
const DependentNameType* T) {
return VisitNestedNameSpecifier(T->getQualifier());
}
bool UnnamedLocalNoLinkageFinder::VisitDependentTemplateSpecializationType(
const DependentTemplateSpecializationType* T) {
if (auto *Q = T->getQualifier())
return VisitNestedNameSpecifier(Q);
return false;
}
bool UnnamedLocalNoLinkageFinder::VisitPackExpansionType(
const PackExpansionType* T) {
return Visit(T->getPattern());
}
bool UnnamedLocalNoLinkageFinder::VisitObjCObjectType(const ObjCObjectType *) {
return false;
}
bool UnnamedLocalNoLinkageFinder::VisitObjCInterfaceType(
const ObjCInterfaceType *) {
return false;
}
bool UnnamedLocalNoLinkageFinder::VisitObjCObjectPointerType(
const ObjCObjectPointerType *) {
return false;
}
bool UnnamedLocalNoLinkageFinder::VisitAtomicType(const AtomicType* T) {
return Visit(T->getValueType());
}
bool UnnamedLocalNoLinkageFinder::VisitPipeType(const PipeType* T) {
return false;
}
bool UnnamedLocalNoLinkageFinder::VisitBitIntType(const BitIntType *T) {
return false;
}
bool UnnamedLocalNoLinkageFinder::VisitDependentBitIntType(
const DependentBitIntType *T) {
return false;
}
bool UnnamedLocalNoLinkageFinder::VisitTagDecl(const TagDecl *Tag) {
if (Tag->getDeclContext()->isFunctionOrMethod()) {
S.Diag(SR.getBegin(),
S.getLangOpts().CPlusPlus11 ?
diag::warn_cxx98_compat_template_arg_local_type :
diag::ext_template_arg_local_type)
<< S.Context.getTypeDeclType(Tag) << SR;
return true;
}
if (!Tag->hasNameForLinkage()) {
S.Diag(SR.getBegin(),
S.getLangOpts().CPlusPlus11 ?
diag::warn_cxx98_compat_template_arg_unnamed_type :
diag::ext_template_arg_unnamed_type) << SR;
S.Diag(Tag->getLocation(), diag::note_template_unnamed_type_here);
return true;
}
return false;
}
bool UnnamedLocalNoLinkageFinder::VisitNestedNameSpecifier(
NestedNameSpecifier *NNS) {
assert(NNS);
if (NNS->getPrefix() && VisitNestedNameSpecifier(NNS->getPrefix()))
return true;
switch (NNS->getKind()) {
case NestedNameSpecifier::Identifier:
case NestedNameSpecifier::Namespace:
case NestedNameSpecifier::NamespaceAlias:
case NestedNameSpecifier::Global:
case NestedNameSpecifier::Super:
return false;
case NestedNameSpecifier::TypeSpec:
case NestedNameSpecifier::TypeSpecWithTemplate:
return Visit(QualType(NNS->getAsType(), 0));
}
llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
}
/// Check a template argument against its corresponding
/// template type parameter.
///
/// This routine implements the semantics of C++ [temp.arg.type]. It
/// returns true if an error occurred, and false otherwise.
bool Sema::CheckTemplateArgument(TypeSourceInfo *ArgInfo) {
assert(ArgInfo && "invalid TypeSourceInfo");
QualType Arg = ArgInfo->getType();
SourceRange SR = ArgInfo->getTypeLoc().getSourceRange();
if (Arg->isVariablyModifiedType()) {
return Diag(SR.getBegin(), diag::err_variably_modified_template_arg) << Arg;
} else if (Context.hasSameUnqualifiedType(Arg, Context.OverloadTy)) {
return Diag(SR.getBegin(), diag::err_template_arg_overload_type) << SR;
}
// C++03 [temp.arg.type]p2:
// A local type, a type with no linkage, an unnamed type or a type
// compounded from any of these types shall not be used as a
// template-argument for a template type-parameter.
//
// C++11 allows these, and even in C++03 we allow them as an extension with
// a warning.
if (LangOpts.CPlusPlus11 || Arg->hasUnnamedOrLocalType()) {
UnnamedLocalNoLinkageFinder Finder(*this, SR);
(void)Finder.Visit(Context.getCanonicalType(Arg));
}
return false;
}
enum NullPointerValueKind {
NPV_NotNullPointer,
NPV_NullPointer,
NPV_Error
};
/// Determine whether the given template argument is a null pointer
/// value of the appropriate type.
static NullPointerValueKind
isNullPointerValueTemplateArgument(Sema &S, NonTypeTemplateParmDecl *Param,
QualType ParamType, Expr *Arg,
Decl *Entity = nullptr) {
if (Arg->isValueDependent() || Arg->isTypeDependent())
return NPV_NotNullPointer;
// dllimport'd entities aren't constant but are available inside of template
// arguments.
if (Entity && Entity->hasAttr<DLLImportAttr>())
return NPV_NotNullPointer;
if (!S.isCompleteType(Arg->getExprLoc(), ParamType))
llvm_unreachable(
"Incomplete parameter type in isNullPointerValueTemplateArgument!");
if (!S.getLangOpts().CPlusPlus11)
return NPV_NotNullPointer;
// Determine whether we have a constant expression.
ExprResult ArgRV = S.DefaultFunctionArrayConversion(Arg);
if (ArgRV.isInvalid())
return NPV_Error;
Arg = ArgRV.get();
Expr::EvalResult EvalResult;
SmallVector<PartialDiagnosticAt, 8> Notes;
EvalResult.Diag = &Notes;
if (!Arg->EvaluateAsRValue(EvalResult, S.Context) ||
EvalResult.HasSideEffects) {
SourceLocation DiagLoc = Arg->getExprLoc();
// If our only note is the usual "invalid subexpression" note, just point
// the caret at its location rather than producing an essentially
// redundant note.
if (Notes.size() == 1 && Notes[0].second.getDiagID() ==
diag::note_invalid_subexpr_in_const_expr) {
DiagLoc = Notes[0].first;
Notes.clear();
}
S.Diag(DiagLoc, diag::err_template_arg_not_address_constant)
<< Arg->getType() << Arg->getSourceRange();
for (unsigned I = 0, N = Notes.size(); I != N; ++I)
S.Diag(Notes[I].first, Notes[I].second);
S.Diag(Param->getLocation(), diag::note_template_param_here);
return NPV_Error;
}
// C++11 [temp.arg.nontype]p1:
// - an address constant expression of type std::nullptr_t
if (Arg->getType()->isNullPtrType())
return NPV_NullPointer;
// - a constant expression that evaluates to a null pointer value (4.10); or
// - a constant expression that evaluates to a null member pointer value
// (4.11); or
if ((EvalResult.Val.isLValue() && !EvalResult.Val.getLValueBase()) ||
(EvalResult.Val.isMemberPointer() &&
!EvalResult.Val.getMemberPointerDecl())) {
// If our expression has an appropriate type, we've succeeded.
bool ObjCLifetimeConversion;
if (S.Context.hasSameUnqualifiedType(Arg->getType(), ParamType) ||
S.IsQualificationConversion(Arg->getType(), ParamType, false,
ObjCLifetimeConversion))
return NPV_NullPointer;
// The types didn't match, but we know we got a null pointer; complain,
// then recover as if the types were correct.
S.Diag(Arg->getExprLoc(), diag::err_template_arg_wrongtype_null_constant)
<< Arg->getType() << ParamType << Arg->getSourceRange();
S.Diag(Param->getLocation(), diag::note_template_param_here);
return NPV_NullPointer;
}
// If we don't have a null pointer value, but we do have a NULL pointer
// constant, suggest a cast to the appropriate type.
if (Arg->isNullPointerConstant(S.Context, Expr::NPC_NeverValueDependent)) {
std::string Code = "static_cast<" + ParamType.getAsString() + ">(";
S.Diag(Arg->getExprLoc(), diag::err_template_arg_untyped_null_constant)
<< ParamType << FixItHint::CreateInsertion(Arg->getBeginLoc(), Code)
<< FixItHint::CreateInsertion(S.getLocForEndOfToken(Arg->getEndLoc()),
")");
S.Diag(Param->getLocation(), diag::note_template_param_here);
return NPV_NullPointer;
}
// FIXME: If we ever want to support general, address-constant expressions
// as non-type template arguments, we should return the ExprResult here to
// be interpreted by the caller.
return NPV_NotNullPointer;
}
/// Checks whether the given template argument is compatible with its
/// template parameter.
static bool CheckTemplateArgumentIsCompatibleWithParameter(
Sema &S, NonTypeTemplateParmDecl *Param, QualType ParamType, Expr *ArgIn,
Expr *Arg, QualType ArgType) {
bool ObjCLifetimeConversion;
if (ParamType->isPointerType() &&
!ParamType->castAs<PointerType>()->getPointeeType()->isFunctionType() &&
S.IsQualificationConversion(ArgType, ParamType, false,
ObjCLifetimeConversion)) {
// For pointer-to-object types, qualification conversions are
// permitted.
} else {
if (const ReferenceType *ParamRef = ParamType->getAs<ReferenceType>()) {
if (!ParamRef->getPointeeType()->isFunctionType()) {
// C++ [temp.arg.nontype]p5b3:
// For a non-type template-parameter of type reference to
// object, no conversions apply. The type referred to by the
// reference may be more cv-qualified than the (otherwise
// identical) type of the template- argument. The
// template-parameter is bound directly to the
// template-argument, which shall be an lvalue.
// FIXME: Other qualifiers?
unsigned ParamQuals = ParamRef->getPointeeType().getCVRQualifiers();
unsigned ArgQuals = ArgType.getCVRQualifiers();
if ((ParamQuals | ArgQuals) != ParamQuals) {
S.Diag(Arg->getBeginLoc(),
diag::err_template_arg_ref_bind_ignores_quals)
<< ParamType << Arg->getType() << Arg->getSourceRange();
S.Diag(Param->getLocation(), diag::note_template_param_here);
return true;
}
}
}
// At this point, the template argument refers to an object or
// function with external linkage. We now need to check whether the
// argument and parameter types are compatible.
if (!S.Context.hasSameUnqualifiedType(ArgType,
ParamType.getNonReferenceType())) {
// We can't perform this conversion or binding.
if (ParamType->isReferenceType())
S.Diag(Arg->getBeginLoc(), diag::err_template_arg_no_ref_bind)
<< ParamType << ArgIn->getType() << Arg->getSourceRange();
else
S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_convertible)
<< ArgIn->getType() << ParamType << Arg->getSourceRange();
S.Diag(Param->getLocation(), diag::note_template_param_here);
return true;
}
}
return false;
}
/// Checks whether the given template argument is the address
/// of an object or function according to C++ [temp.arg.nontype]p1.
static bool
CheckTemplateArgumentAddressOfObjectOrFunction(Sema &S,
NonTypeTemplateParmDecl *Param,
QualType ParamType,
Expr *ArgIn,
TemplateArgument &Converted) {
bool Invalid = false;
Expr *Arg = ArgIn;
QualType ArgType = Arg->getType();
bool AddressTaken = false;
SourceLocation AddrOpLoc;
if (S.getLangOpts().MicrosoftExt) {
// Microsoft Visual C++ strips all casts, allows an arbitrary number of
// dereference and address-of operators.
Arg = Arg->IgnoreParenCasts();
bool ExtWarnMSTemplateArg = false;
UnaryOperatorKind FirstOpKind;
SourceLocation FirstOpLoc;
while (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
UnaryOperatorKind UnOpKind = UnOp->getOpcode();
if (UnOpKind == UO_Deref)
ExtWarnMSTemplateArg = true;
if (UnOpKind == UO_AddrOf || UnOpKind == UO_Deref) {
Arg = UnOp->getSubExpr()->IgnoreParenCasts();
if (!AddrOpLoc.isValid()) {
FirstOpKind = UnOpKind;
FirstOpLoc = UnOp->getOperatorLoc();
}
} else
break;
}
if (FirstOpLoc.isValid()) {
if (ExtWarnMSTemplateArg)
S.Diag(ArgIn->getBeginLoc(), diag::ext_ms_deref_template_argument)
<< ArgIn->getSourceRange();
if (FirstOpKind == UO_AddrOf)
AddressTaken = true;
else if (Arg->getType()->isPointerType()) {
// We cannot let pointers get dereferenced here, that is obviously not a
// constant expression.
assert(FirstOpKind == UO_Deref);
S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
<< Arg->getSourceRange();
}
}
} else {
// See through any implicit casts we added to fix the type.
Arg = Arg->IgnoreImpCasts();
// C++ [temp.arg.nontype]p1:
//
// A template-argument for a non-type, non-template
// template-parameter shall be one of: [...]
//
// -- the address of an object or function with external
// linkage, including function templates and function
// template-ids but excluding non-static class members,
// expressed as & id-expression where the & is optional if
// the name refers to a function or array, or if the
// corresponding template-parameter is a reference; or
// In C++98/03 mode, give an extension warning on any extra parentheses.
// See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#773
bool ExtraParens = false;
while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
if (!Invalid && !ExtraParens) {
S.Diag(Arg->getBeginLoc(),
S.getLangOpts().CPlusPlus11
? diag::warn_cxx98_compat_template_arg_extra_parens
: diag::ext_template_arg_extra_parens)
<< Arg->getSourceRange();
ExtraParens = true;
}
Arg = Parens->getSubExpr();
}
while (SubstNonTypeTemplateParmExpr *subst =
dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
Arg = subst->getReplacement()->IgnoreImpCasts();
if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
if (UnOp->getOpcode() == UO_AddrOf) {
Arg = UnOp->getSubExpr();
AddressTaken = true;
AddrOpLoc = UnOp->getOperatorLoc();
}
}
while (SubstNonTypeTemplateParmExpr *subst =
dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
Arg = subst->getReplacement()->IgnoreImpCasts();
}
ValueDecl *Entity = nullptr;
if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg))
Entity = DRE->getDecl();
else if (CXXUuidofExpr *CUE = dyn_cast<CXXUuidofExpr>(Arg))
Entity = CUE->getGuidDecl();
// If our parameter has pointer type, check for a null template value.
if (ParamType->isPointerType() || ParamType->isNullPtrType()) {
switch (isNullPointerValueTemplateArgument(S, Param, ParamType, ArgIn,
Entity)) {
case NPV_NullPointer:
S.Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
Converted = TemplateArgument(S.Context.getCanonicalType(ParamType),
/*isNullPtr=*/true);
return false;
case NPV_Error:
return true;
case NPV_NotNullPointer:
break;
}
}
// Stop checking the precise nature of the argument if it is value dependent,
// it should be checked when instantiated.
if (Arg->isValueDependent()) {
Converted = TemplateArgument(ArgIn);
return false;
}
if (!Entity) {
S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
<< Arg->getSourceRange();
S.Diag(Param->getLocation(), diag::note_template_param_here);
return true;
}
// Cannot refer to non-static data members
if (isa<FieldDecl>(Entity) || isa<IndirectFieldDecl>(Entity)) {
S.Diag(Arg->getBeginLoc(), diag::err_template_arg_field)
<< Entity << Arg->getSourceRange();
S.Diag(Param->getLocation(), diag::note_template_param_here);
return true;
}
// Cannot refer to non-static member functions
if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Entity)) {
if (!Method->isStatic()) {
S.Diag(Arg->getBeginLoc(), diag::err_template_arg_method)
<< Method << Arg->getSourceRange();
S.Diag(Param->getLocation(), diag::note_template_param_here);
return true;
}
}
FunctionDecl *Func = dyn_cast<FunctionDecl>(Entity);
VarDecl *Var = dyn_cast<VarDecl>(Entity);
MSGuidDecl *Guid = dyn_cast<MSGuidDecl>(Entity);
// A non-type template argument must refer to an object or function.
if (!Func && !Var && !Guid) {
// We found something, but we don't know specifically what it is.
S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_object_or_func)
<< Arg->getSourceRange();
S.Diag(Entity->getLocation(), diag::note_template_arg_refers_here);
return true;
}
// Address / reference template args must have external linkage in C++98.
if (Entity->getFormalLinkage() == InternalLinkage) {
S.Diag(Arg->getBeginLoc(),
S.getLangOpts().CPlusPlus11
? diag::warn_cxx98_compat_template_arg_object_internal
: diag::ext_template_arg_object_internal)
<< !Func << Entity << Arg->getSourceRange();
S.Diag(Entity->getLocation(), diag::note_template_arg_internal_object)
<< !Func;
} else if (!Entity->hasLinkage()) {
S.Diag(Arg->getBeginLoc(), diag::err_template_arg_object_no_linkage)
<< !Func << Entity << Arg->getSourceRange();
S.Diag(Entity->getLocation(), diag::note_template_arg_internal_object)
<< !Func;
return true;
}
if (Var) {
// A value of reference type is not an object.
if (Var->getType()->isReferenceType()) {
S.Diag(Arg->getBeginLoc(), diag::err_template_arg_reference_var)
<< Var->getType() << Arg->getSourceRange();
S.Diag(Param->getLocation(), diag::note_template_param_here);
return true;
}
// A template argument must have static storage duration.
if (Var->getTLSKind()) {
S.Diag(Arg->getBeginLoc(), diag::err_template_arg_thread_local)
<< Arg->getSourceRange();
S.Diag(Var->getLocation(), diag::note_template_arg_refers_here);
return true;
}
}
if (AddressTaken && ParamType->isReferenceType()) {
// If we originally had an address-of operator, but the
// parameter has reference type, complain and (if things look
// like they will work) drop the address-of operator.
if (!S.Context.hasSameUnqualifiedType(Entity->getType(),
ParamType.getNonReferenceType())) {
S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
<< ParamType;
S.Diag(Param->getLocation(), diag::note_template_param_here);
return true;
}
S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
<< ParamType
<< FixItHint::CreateRemoval(AddrOpLoc);
S.Diag(Param->getLocation(), diag::note_template_param_here);
ArgType = Entity->getType();
}
// If the template parameter has pointer type, either we must have taken the
// address or the argument must decay to a pointer.
if (!AddressTaken && ParamType->isPointerType()) {
if (Func) {
// Function-to-pointer decay.
ArgType = S.Context.getPointerType(Func->getType());
} else if (Entity->getType()->isArrayType()) {
// Array-to-pointer decay.
ArgType = S.Context.getArrayDecayedType(Entity->getType());
} else {
// If the template parameter has pointer type but the address of
// this object was not taken, complain and (possibly) recover by
// taking the address of the entity.
ArgType = S.Context.getPointerType(Entity->getType());
if (!S.Context.hasSameUnqualifiedType(ArgType, ParamType)) {
S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_address_of)
<< ParamType;
S.Diag(Param->getLocation(), diag::note_template_param_here);
return true;
}
S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_address_of)
<< ParamType << FixItHint::CreateInsertion(Arg->getBeginLoc(), "&");
S.Diag(Param->getLocation(), diag::note_template_param_here);
}
}
if (CheckTemplateArgumentIsCompatibleWithParameter(S, Param, ParamType, ArgIn,
Arg, ArgType))
return true;
// Create the template argument.
Converted = TemplateArgument(cast<ValueDecl>(Entity->getCanonicalDecl()),
S.Context.getCanonicalType(ParamType));
S.MarkAnyDeclReferenced(Arg->getBeginLoc(), Entity, false);
return false;
}
/// Checks whether the given template argument is a pointer to
/// member constant according to C++ [temp.arg.nontype]p1.
static bool CheckTemplateArgumentPointerToMember(Sema &S,
NonTypeTemplateParmDecl *Param,
QualType ParamType,
Expr *&ResultArg,
TemplateArgument &Converted) {
bool Invalid = false;
Expr *Arg = ResultArg;
bool ObjCLifetimeConversion;
// C++ [temp.arg.nontype]p1:
//
// A template-argument for a non-type, non-template
// template-parameter shall be one of: [...]
//
// -- a pointer to member expressed as described in 5.3.1.
DeclRefExpr *DRE = nullptr;
// In C++98/03 mode, give an extension warning on any extra parentheses.
// See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#773
bool ExtraParens = false;
while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
if (!Invalid && !ExtraParens) {
S.Diag(Arg->getBeginLoc(),
S.getLangOpts().CPlusPlus11
? diag::warn_cxx98_compat_template_arg_extra_parens
: diag::ext_template_arg_extra_parens)
<< Arg->getSourceRange();
ExtraParens = true;
}
Arg = Parens->getSubExpr();
}
while (SubstNonTypeTemplateParmExpr *subst =
dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
Arg = subst->getReplacement()->IgnoreImpCasts();
// A pointer-to-member constant written &Class::member.
if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
if (UnOp->getOpcode() == UO_AddrOf) {
DRE = dyn_cast<DeclRefExpr>(UnOp->getSubExpr());
if (DRE && !DRE->getQualifier())
DRE = nullptr;
}
}
// A constant of pointer-to-member type.
else if ((DRE = dyn_cast<DeclRefExpr>(Arg))) {
ValueDecl *VD = DRE->getDecl();
if (VD->getType()->isMemberPointerType()) {
if (isa<NonTypeTemplateParmDecl>(VD)) {
if (Arg->isTypeDependent() || Arg->isValueDependent()) {
Converted = TemplateArgument(Arg);
} else {
VD = cast<ValueDecl>(VD->getCanonicalDecl());
Converted = TemplateArgument(VD, ParamType);
}
return Invalid;
}
}
DRE = nullptr;
}
ValueDecl *Entity = DRE ? DRE->getDecl() : nullptr;
// Check for a null pointer value.
switch (isNullPointerValueTemplateArgument(S, Param, ParamType, ResultArg,
Entity)) {
case NPV_Error:
return true;
case NPV_NullPointer:
S.Diag(ResultArg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
Converted = TemplateArgument(S.Context.getCanonicalType(ParamType),
/*isNullPtr*/true);
return false;
case NPV_NotNullPointer:
break;
}
if (S.IsQualificationConversion(ResultArg->getType(),
ParamType.getNonReferenceType(), false,
ObjCLifetimeConversion)) {
ResultArg = S.ImpCastExprToType(ResultArg, ParamType, CK_NoOp,
ResultArg->getValueKind())
.get();
} else if (!S.Context.hasSameUnqualifiedType(
ResultArg->getType(), ParamType.getNonReferenceType())) {
// We can't perform this conversion.
S.Diag(ResultArg->getBeginLoc(), diag::err_template_arg_not_convertible)
<< ResultArg->getType() << ParamType << ResultArg->getSourceRange();
S.Diag(Param->getLocation(), diag::note_template_param_here);
return true;
}
if (!DRE)
return S.Diag(Arg->getBeginLoc(),
diag::err_template_arg_not_pointer_to_member_form)
<< Arg->getSourceRange();
if (isa<FieldDecl>(DRE->getDecl()) ||
isa<IndirectFieldDecl>(DRE->getDecl()) ||
isa<CXXMethodDecl>(DRE->getDecl())) {
assert((isa<FieldDecl>(DRE->getDecl()) ||
isa<IndirectFieldDecl>(DRE->getDecl()) ||
!cast<CXXMethodDecl>(DRE->getDecl())->isStatic()) &&
"Only non-static member pointers can make it here");
// Okay: this is the address of a non-static member, and therefore
// a member pointer constant.
if (Arg->isTypeDependent() || Arg->isValueDependent()) {
Converted = TemplateArgument(Arg);
} else {
ValueDecl *D = cast<ValueDecl>(DRE->getDecl()->getCanonicalDecl());
Converted = TemplateArgument(D, S.Context.getCanonicalType(ParamType));
}
return Invalid;
}
// We found something else, but we don't know specifically what it is.
S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_pointer_to_member_form)
<< Arg->getSourceRange();
S.Diag(DRE->getDecl()->getLocation(), diag::note_template_arg_refers_here);
return true;
}
/// Check a template argument against its corresponding
/// non-type template parameter.
///
/// This routine implements the semantics of C++ [temp.arg.nontype].
/// If an error occurred, it returns ExprError(); otherwise, it
/// returns the converted template argument. \p ParamType is the
/// type of the non-type template parameter after it has been instantiated.
ExprResult Sema::CheckTemplateArgument(NonTypeTemplateParmDecl *Param,
QualType ParamType, Expr *Arg,
TemplateArgument &Converted,
CheckTemplateArgumentKind CTAK) {
SourceLocation StartLoc = Arg->getBeginLoc();
// If the parameter type somehow involves auto, deduce the type now.
DeducedType *DeducedT = ParamType->getContainedDeducedType();
if (getLangOpts().CPlusPlus17 && DeducedT && !DeducedT->isDeduced()) {
// During template argument deduction, we allow 'decltype(auto)' to
// match an arbitrary dependent argument.
// FIXME: The language rules don't say what happens in this case.
// FIXME: We get an opaque dependent type out of decltype(auto) if the
// expression is merely instantiation-dependent; is this enough?
if (CTAK == CTAK_Deduced && Arg->isTypeDependent()) {
auto *AT = dyn_cast<AutoType>(DeducedT);
if (AT && AT->isDecltypeAuto()) {
Converted = TemplateArgument(Arg);
return Arg;
}
}
// When checking a deduced template argument, deduce from its type even if
// the type is dependent, in order to check the types of non-type template
// arguments line up properly in partial ordering.
Optional<unsigned> Depth = Param->getDepth() + 1;
Expr *DeductionArg = Arg;
if (auto *PE = dyn_cast<PackExpansionExpr>(DeductionArg))
DeductionArg = PE->getPattern();
TypeSourceInfo *TSI =
Context.getTrivialTypeSourceInfo(ParamType, Param->getLocation());
if (isa<DeducedTemplateSpecializationType>(DeducedT)) {
InitializedEntity Entity =
InitializedEntity::InitializeTemplateParameter(ParamType, Param);
InitializationKind Kind = InitializationKind::CreateForInit(
DeductionArg->getBeginLoc(), /*DirectInit*/false, DeductionArg);
Expr *Inits[1] = {DeductionArg};
ParamType =
DeduceTemplateSpecializationFromInitializer(TSI, Entity, Kind, Inits);
if (ParamType.isNull())
return ExprError();
} else if (DeduceAutoType(
TSI, DeductionArg, ParamType, Depth,
// We do not check constraints right now because the
// immediately-declared constraint of the auto type is also
// an associated constraint, and will be checked along with
// the other associated constraints after checking the
// template argument list.
/*IgnoreConstraints=*/true) == DAR_Failed) {
Diag(Arg->getExprLoc(),
diag::err_non_type_template_parm_type_deduction_failure)
<< Param->getDeclName() << Param->getType() << Arg->getType()
<< Arg->getSourceRange();
Diag(Param->getLocation(), diag::note_template_param_here);
return ExprError();
}
// CheckNonTypeTemplateParameterType will produce a diagnostic if there's
// an error. The error message normally references the parameter
// declaration, but here we'll pass the argument location because that's
// where the parameter type is deduced.
ParamType = CheckNonTypeTemplateParameterType(ParamType, Arg->getExprLoc());
if (ParamType.isNull()) {
Diag(Param->getLocation(), diag::note_template_param_here);
return ExprError();
}
}
// We should have already dropped all cv-qualifiers by now.
assert(!ParamType.hasQualifiers() &&
"non-type template parameter type cannot be qualified");
// FIXME: When Param is a reference, should we check that Arg is an lvalue?
if (CTAK == CTAK_Deduced &&
(ParamType->isReferenceType()
? !Context.hasSameType(ParamType.getNonReferenceType(),
Arg->getType())
: !Context.hasSameUnqualifiedType(ParamType, Arg->getType()))) {
// FIXME: If either type is dependent, we skip the check. This isn't
// correct, since during deduction we're supposed to have replaced each
// template parameter with some unique (non-dependent) placeholder.
// FIXME: If the argument type contains 'auto', we carry on and fail the
// type check in order to force specific types to be more specialized than
// 'auto'. It's not clear how partial ordering with 'auto' is supposed to
// work. Similarly for CTAD, when comparing 'A<x>' against 'A'.
if ((ParamType->isDependentType() || Arg->isTypeDependent()) &&
!Arg->getType()->getContainedDeducedType()) {
Converted = TemplateArgument(Arg);
return Arg;
}
// FIXME: This attempts to implement C++ [temp.deduct.type]p17. Per DR1770,
// we should actually be checking the type of the template argument in P,
// not the type of the template argument deduced from A, against the
// template parameter type.
Diag(StartLoc, diag::err_deduced_non_type_template_arg_type_mismatch)
<< Arg->getType()
<< ParamType.getUnqualifiedType();
Diag(Param->getLocation(), diag::note_template_param_here);
return ExprError();
}
// If either the parameter has a dependent type or the argument is
// type-dependent, there's nothing we can check now. The argument only
// contains an unexpanded pack during partial ordering, and there's
// nothing more we can check in that case.
if (ParamType->isDependentType() || Arg->isTypeDependent() ||
Arg->containsUnexpandedParameterPack()) {
// Force the argument to the type of the parameter to maintain invariants.
auto *PE = dyn_cast<PackExpansionExpr>(Arg);
if (PE)
Arg = PE->getPattern();
ExprResult E = ImpCastExprToType(
Arg, ParamType.getNonLValueExprType(Context), CK_Dependent,
ParamType->isLValueReferenceType() ? VK_LValue
: ParamType->isRValueReferenceType() ? VK_XValue
: VK_PRValue);
if (E.isInvalid())
return ExprError();
if (PE) {
// Recreate a pack expansion if we unwrapped one.
E = new (Context)
PackExpansionExpr(E.get()->getType(), E.get(), PE->getEllipsisLoc(),
PE->getNumExpansions());
}
Converted = TemplateArgument(E.get());
return E;
}
// The initialization of the parameter from the argument is
// a constant-evaluated context.
EnterExpressionEvaluationContext ConstantEvaluated(
*this, Sema::ExpressionEvaluationContext::ConstantEvaluated);
if (getLangOpts().CPlusPlus17) {
QualType CanonParamType = Context.getCanonicalType(ParamType);
// Avoid making a copy when initializing a template parameter of class type
// from a template parameter object of the same type. This is going beyond
// the standard, but is required for soundness: in
// template<A a> struct X { X *p; X<a> *q; };
// ... we need p and q to have the same type.
//
// Similarly, don't inject a call to a copy constructor when initializing
// from a template parameter of the same type.
Expr *InnerArg = Arg->IgnoreParenImpCasts();
if (ParamType->isRecordType() && isa<DeclRefExpr>(InnerArg) &&
Context.hasSameUnqualifiedType(ParamType, InnerArg->getType())) {
NamedDecl *ND = cast<DeclRefExpr>(InnerArg)->getDecl();
if (auto *TPO = dyn_cast<TemplateParamObjectDecl>(ND)) {
Converted = TemplateArgument(TPO, CanonParamType);
return Arg;
}
if (isa<NonTypeTemplateParmDecl>(ND)) {
Converted = TemplateArgument(Arg);
return Arg;
}
}
// C++17 [temp.arg.nontype]p1:
// A template-argument for a non-type template parameter shall be
// a converted constant expression of the type of the template-parameter.
APValue Value;
ExprResult ArgResult = CheckConvertedConstantExpression(
Arg, ParamType, Value, CCEK_TemplateArg, Param);
if (ArgResult.isInvalid())
return ExprError();
// For a value-dependent argument, CheckConvertedConstantExpression is
// permitted (and expected) to be unable to determine a value.
if (ArgResult.get()->isValueDependent()) {
Converted = TemplateArgument(ArgResult.get());
return ArgResult;
}
// Convert the APValue to a TemplateArgument.
switch (Value.getKind()) {
case APValue::None:
assert(ParamType->isNullPtrType());
Converted = TemplateArgument(CanonParamType, /*isNullPtr*/true);
break;
case APValue::Indeterminate:
llvm_unreachable("result of constant evaluation should be initialized");
break;
case APValue::Int:
assert(ParamType->isIntegralOrEnumerationType());
Converted = TemplateArgument(Context, Value.getInt(), CanonParamType);
break;
case APValue::MemberPointer: {
assert(ParamType->isMemberPointerType());
// FIXME: We need TemplateArgument representation and mangling for these.
if (!Value.getMemberPointerPath().empty()) {
Diag(Arg->getBeginLoc(),
diag::err_template_arg_member_ptr_base_derived_not_supported)
<< Value.getMemberPointerDecl() << ParamType
<< Arg->getSourceRange();
return ExprError();
}
auto *VD = const_cast<ValueDecl*>(Value.getMemberPointerDecl());
Converted = VD ? TemplateArgument(VD, CanonParamType)
: TemplateArgument(CanonParamType, /*isNullPtr*/true);
break;
}
case APValue::LValue: {
// For a non-type template-parameter of pointer or reference type,
// the value of the constant expression shall not refer to
assert(ParamType->isPointerType() || ParamType->isReferenceType() ||
ParamType->isNullPtrType());
// -- a temporary object
// -- a string literal
// -- the result of a typeid expression, or
// -- a predefined __func__ variable
APValue::LValueBase Base = Value.getLValueBase();
auto *VD = const_cast<ValueDecl *>(Base.dyn_cast<const ValueDecl *>());
if (Base &&
(!VD ||
isa<LifetimeExtendedTemporaryDecl, UnnamedGlobalConstantDecl>(VD))) {
Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
<< Arg->getSourceRange();
return ExprError();
}
// -- a subobject
// FIXME: Until C++20
if (Value.hasLValuePath() && Value.getLValuePath().size() == 1 &&
VD && VD->getType()->isArrayType() &&
Value.getLValuePath()[0].getAsArrayIndex() == 0 &&
!Value.isLValueOnePastTheEnd() && ParamType->isPointerType()) {
// Per defect report (no number yet):
// ... other than a pointer to the first element of a complete array
// object.
} else if (!Value.hasLValuePath() || Value.getLValuePath().size() ||
Value.isLValueOnePastTheEnd()) {
Diag(StartLoc, diag::err_non_type_template_arg_subobject)
<< Value.getAsString(Context, ParamType);
return ExprError();
}
assert((VD || !ParamType->isReferenceType()) &&
"null reference should not be a constant expression");
assert((!VD || !ParamType->isNullPtrType()) &&
"non-null value of type nullptr_t?");
Converted = VD ? TemplateArgument(VD, CanonParamType)
: TemplateArgument(CanonParamType, /*isNullPtr*/true);
break;
}
case APValue::Struct:
case APValue::Union:
// Get or create the corresponding template parameter object.
Converted = TemplateArgument(
Context.getTemplateParamObjectDecl(CanonParamType, Value),
CanonParamType);
break;
case APValue::AddrLabelDiff:
return Diag(StartLoc, diag::err_non_type_template_arg_addr_label_diff);
case APValue::FixedPoint:
case APValue::Float:
case APValue::ComplexInt:
case APValue::ComplexFloat:
case APValue::Vector:
case APValue::Array:
return Diag(StartLoc, diag::err_non_type_template_arg_unsupported)
<< ParamType;
}
return ArgResult.get();
}
// C++ [temp.arg.nontype]p5:
// The following conversions are performed on each expression used
// as a non-type template-argument. If a non-type
// template-argument cannot be converted to the type of the
// corresponding template-parameter then the program is
// ill-formed.
if (ParamType->isIntegralOrEnumerationType()) {
// C++11:
// -- for a non-type template-parameter of integral or
// enumeration type, conversions permitted in a converted
// constant expression are applied.
//
// C++98:
// -- for a non-type template-parameter of integral or
// enumeration type, integral promotions (4.5) and integral
// conversions (4.7) are applied.
if (getLangOpts().CPlusPlus11) {
// C++ [temp.arg.nontype]p1:
// A template-argument for a non-type, non-template template-parameter
// shall be one of:
//
// -- for a non-type template-parameter of integral or enumeration
// type, a converted constant expression of the type of the
// template-parameter; or
llvm::APSInt Value;
ExprResult ArgResult =
CheckConvertedConstantExpression(Arg, ParamType, Value,
CCEK_TemplateArg);
if (ArgResult.isInvalid())
return ExprError();
// We can't check arbitrary value-dependent arguments.
if (ArgResult.get()->isValueDependent()) {
Converted = TemplateArgument(ArgResult.get());
return ArgResult;
}
// Widen the argument value to sizeof(parameter type). This is almost
// always a no-op, except when the parameter type is bool. In
// that case, this may extend the argument from 1 bit to 8 bits.
QualType IntegerType = ParamType;
if (const EnumType *Enum = IntegerType->getAs<EnumType>())
IntegerType = Enum->getDecl()->getIntegerType();
Value = Value.extOrTrunc(IntegerType->isBitIntType()
? Context.getIntWidth(IntegerType)
: Context.getTypeSize(IntegerType));
Converted = TemplateArgument(Context, Value,
Context.getCanonicalType(ParamType));
return ArgResult;
}
ExprResult ArgResult = DefaultLvalueConversion(Arg);
if (ArgResult.isInvalid())
return ExprError();
Arg = ArgResult.get();
QualType ArgType = Arg->getType();
// C++ [temp.arg.nontype]p1:
// A template-argument for a non-type, non-template
// template-parameter shall be one of:
//
// -- an integral constant-expression of integral or enumeration
// type; or
// -- the name of a non-type template-parameter; or
llvm::APSInt Value;
if (!ArgType->isIntegralOrEnumerationType()) {
Diag(Arg->getBeginLoc(), diag::err_template_arg_not_integral_or_enumeral)
<< ArgType << Arg->getSourceRange();
Diag(Param->getLocation(), diag::note_template_param_here);
return ExprError();
} else if (!Arg->isValueDependent()) {
class TmplArgICEDiagnoser : public VerifyICEDiagnoser {
QualType T;
public:
TmplArgICEDiagnoser(QualType T) : T(T) { }
SemaDiagnosticBuilder diagnoseNotICE(Sema &S,
SourceLocation Loc) override {
return S.Diag(Loc, diag::err_template_arg_not_ice) << T;
}
} Diagnoser(ArgType);
Arg = VerifyIntegerConstantExpression(Arg, &Value, Diagnoser).get();
if (!Arg)
return ExprError();
}
// From here on out, all we care about is the unqualified form
// of the argument type.
ArgType = ArgType.getUnqualifiedType();
// Try to convert the argument to the parameter's type.
if (Context.hasSameType(ParamType, ArgType)) {
// Okay: no conversion necessary
} else if (ParamType->isBooleanType()) {
// This is an integral-to-boolean conversion.
Arg = ImpCastExprToType(Arg, ParamType, CK_IntegralToBoolean).get();
} else if (IsIntegralPromotion(Arg, ArgType, ParamType) ||
!ParamType->isEnumeralType()) {
// This is an integral promotion or conversion.
Arg = ImpCastExprToType(Arg, ParamType, CK_IntegralCast).get();
} else {
// We can't perform this conversion.
Diag(Arg->getBeginLoc(), diag::err_template_arg_not_convertible)
<< Arg->getType() << ParamType << Arg->getSourceRange();
Diag(Param->getLocation(), diag::note_template_param_here);
return ExprError();
}
// Add the value of this argument to the list of converted
// arguments. We use the bitwidth and signedness of the template
// parameter.
if (Arg->isValueDependent()) {
// The argument is value-dependent. Create a new
// TemplateArgument with the converted expression.
Converted = TemplateArgument(Arg);
return Arg;
}
QualType IntegerType = Context.getCanonicalType(ParamType);
if (const EnumType *Enum = IntegerType->getAs<EnumType>())
IntegerType = Context.getCanonicalType(Enum->getDecl()->getIntegerType());
if (ParamType->isBooleanType()) {
// Value must be zero or one.
Value = Value != 0;
unsigned AllowedBits = Context.getTypeSize(IntegerType);
if (Value.getBitWidth() != AllowedBits)
Value = Value.extOrTrunc(AllowedBits);
Value.setIsSigned(IntegerType->isSignedIntegerOrEnumerationType());
} else {
llvm::APSInt OldValue = Value;
// Coerce the template argument's value to the value it will have
// based on the template parameter's type.
unsigned AllowedBits = IntegerType->isBitIntType()
? Context.getIntWidth(IntegerType)
: Context.getTypeSize(IntegerType);
if (Value.getBitWidth() != AllowedBits)
Value = Value.extOrTrunc(AllowedBits);
Value.setIsSigned(IntegerType->isSignedIntegerOrEnumerationType());
// Complain if an unsigned parameter received a negative value.
if (IntegerType->isUnsignedIntegerOrEnumerationType() &&
(OldValue.isSigned() && OldValue.isNegative())) {
Diag(Arg->getBeginLoc(), diag::warn_template_arg_negative)
<< toString(OldValue, 10) << toString(Value, 10) << Param->getType()
<< Arg->getSourceRange();
Diag(Param->getLocation(), diag::note_template_param_here);
}
// Complain if we overflowed the template parameter's type.
unsigned RequiredBits;
if (IntegerType->isUnsignedIntegerOrEnumerationType())
RequiredBits = OldValue.getActiveBits();
else if (OldValue.isUnsigned())
RequiredBits = OldValue.getActiveBits() + 1;
else
RequiredBits = OldValue.getMinSignedBits();
if (RequiredBits > AllowedBits) {
Diag(Arg->getBeginLoc(), diag::warn_template_arg_too_large)
<< toString(OldValue, 10) << toString(Value, 10) << Param->getType()
<< Arg->getSourceRange();
Diag(Param->getLocation(), diag::note_template_param_here);
}
}
Converted = TemplateArgument(Context, Value,
ParamType->isEnumeralType()
? Context.getCanonicalType(ParamType)
: IntegerType);
return Arg;
}
QualType ArgType = Arg->getType();
DeclAccessPair FoundResult; // temporary for ResolveOverloadedFunction
// Handle pointer-to-function, reference-to-function, and
// pointer-to-member-function all in (roughly) the same way.
if (// -- For a non-type template-parameter of type pointer to
// function, only the function-to-pointer conversion (4.3) is
// applied. If the template-argument represents a set of
// overloaded functions (or a pointer to such), the matching
// function is selected from the set (13.4).
(ParamType->isPointerType() &&
ParamType->castAs<PointerType>()->getPointeeType()->isFunctionType()) ||
// -- For a non-type template-parameter of type reference to
// function, no conversions apply. If the template-argument
// represents a set of overloaded functions, the matching
// function is selected from the set (13.4).
(ParamType->isReferenceType() &&
ParamType->castAs<ReferenceType>()->getPointeeType()->isFunctionType()) ||
// -- For a non-type template-parameter of type pointer to
// member function, no conversions apply. If the
// template-argument represents a set of overloaded member
// functions, the matching member function is selected from
// the set (13.4).
(ParamType->isMemberPointerType() &&
ParamType->castAs<MemberPointerType>()->getPointeeType()
->isFunctionType())) {
if (Arg->getType() == Context.OverloadTy) {
if (FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Arg, ParamType,
true,
FoundResult)) {
if (DiagnoseUseOfDecl(Fn, Arg->getBeginLoc()))
return ExprError();
Arg = FixOverloadedFunctionReference(Arg, FoundResult, Fn);
ArgType = Arg->getType();
} else
return ExprError();
}
if (!ParamType->isMemberPointerType()) {
if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
ParamType,
Arg, Converted))
return ExprError();
return Arg;
}
if (CheckTemplateArgumentPointerToMember(*this, Param, ParamType, Arg,
Converted))
return ExprError();
return Arg;
}
if (ParamType->isPointerType()) {
// -- for a non-type template-parameter of type pointer to
// object, qualification conversions (4.4) and the
// array-to-pointer conversion (4.2) are applied.
// C++0x also allows a value of std::nullptr_t.
assert(ParamType->getPointeeType()->isIncompleteOrObjectType() &&
"Only object pointers allowed here");
if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
ParamType,
Arg, Converted))
return ExprError();
return Arg;
}
if (const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>()) {
// -- For a non-type template-parameter of type reference to
// object, no conversions apply. The type referred to by the
// reference may be more cv-qualified than the (otherwise
// identical) type of the template-argument. The
// template-parameter is bound directly to the
// template-argument, which must be an lvalue.
assert(ParamRefType->getPointeeType()->isIncompleteOrObjectType() &&
"Only object references allowed here");
if (Arg->getType() == Context.OverloadTy) {
if (FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Arg,
ParamRefType->getPointeeType(),
true,
FoundResult)) {
if (DiagnoseUseOfDecl(Fn, Arg->getBeginLoc()))
return ExprError();
Arg = FixOverloadedFunctionReference(Arg, FoundResult, Fn);
ArgType = Arg->getType();
} else
return ExprError();
}
if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
ParamType,
Arg, Converted))
return ExprError();
return Arg;
}
// Deal with parameters of type std::nullptr_t.
if (ParamType->isNullPtrType()) {
if (Arg->isTypeDependent() || Arg->isValueDependent()) {
Converted = TemplateArgument(Arg);
return Arg;
}
switch (isNullPointerValueTemplateArgument(*this, Param, ParamType, Arg)) {
case NPV_NotNullPointer:
Diag(Arg->getExprLoc(), diag::err_template_arg_not_convertible)
<< Arg->getType() << ParamType;
Diag(Param->getLocation(), diag::note_template_param_here);
return ExprError();
case NPV_Error:
return ExprError();
case NPV_NullPointer:
Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
Converted = TemplateArgument(Context.getCanonicalType(ParamType),
/*isNullPtr*/true);
return Arg;
}
}
// -- For a non-type template-parameter of type pointer to data
// member, qualification conversions (4.4) are applied.
assert(ParamType->isMemberPointerType() && "Only pointers to members remain");
if (CheckTemplateArgumentPointerToMember(*this, Param, ParamType, Arg,
Converted))
return ExprError();
return Arg;
}
static void DiagnoseTemplateParameterListArityMismatch(
Sema &S, TemplateParameterList *New, TemplateParameterList *Old,
Sema::TemplateParameterListEqualKind Kind, SourceLocation TemplateArgLoc);
/// Check a template argument against its corresponding
/// template template parameter.
///
/// This routine implements the semantics of C++ [temp.arg.template].
/// It returns true if an error occurred, and false otherwise.
bool Sema::CheckTemplateTemplateArgument(TemplateTemplateParmDecl *Param,
TemplateParameterList *Params,
TemplateArgumentLoc &Arg) {
TemplateName Name = Arg.getArgument().getAsTemplateOrTemplatePattern();
TemplateDecl *Template = Name.getAsTemplateDecl();
if (!Template) {
// Any dependent template name is fine.
assert(Name.isDependent() && "Non-dependent template isn't a declaration?");
return false;
}
if (Template->isInvalidDecl())
return true;
// C++0x [temp.arg.template]p1:
// A template-argument for a template template-parameter shall be
// the name of a class template or an alias template, expressed as an
// id-expression. When the template-argument names a class template, only
// primary class templates are considered when matching the
// template template argument with the corresponding parameter;
// partial specializations are not considered even if their
// parameter lists match that of the template template parameter.
//
// Note that we also allow template template parameters here, which
// will happen when we are dealing with, e.g., class template
// partial specializations.
if (!isa<ClassTemplateDecl>(Template) &&
!isa<TemplateTemplateParmDecl>(Template) &&
!isa<TypeAliasTemplateDecl>(Template) &&
!isa<BuiltinTemplateDecl>(Template)) {
assert(isa<FunctionTemplateDecl>(Template) &&
"Only function templates are possible here");
Diag(Arg.getLocation(), diag::err_template_arg_not_valid_template);
Diag(Template->getLocation(), diag::note_template_arg_refers_here_func)
<< Template;
}
// C++1z [temp.arg.template]p3: (DR 150)
// A template-argument matches a template template-parameter P when P
// is at least as specialized as the template-argument A.
// FIXME: We should enable RelaxedTemplateTemplateArgs by default as it is a
// defect report resolution from C++17 and shouldn't be introduced by
// concepts.
if (getLangOpts().RelaxedTemplateTemplateArgs) {
// Quick check for the common case:
// If P contains a parameter pack, then A [...] matches P if each of A's
// template parameters matches the corresponding template parameter in
// the template-parameter-list of P.
if (TemplateParameterListsAreEqual(
Template->getTemplateParameters(), Params, false,
TPL_TemplateTemplateArgumentMatch, Arg.getLocation()) &&
// If the argument has no associated constraints, then the parameter is
// definitely at least as specialized as the argument.
// Otherwise - we need a more thorough check.
!Template->hasAssociatedConstraints())
return false;
if (isTemplateTemplateParameterAtLeastAsSpecializedAs(Params, Template,
Arg.getLocation())) {
// C++2a[temp.func.order]p2
// [...] If both deductions succeed, the partial ordering selects the
// more constrained template as described by the rules in
// [temp.constr.order].
SmallVector<const Expr *, 3> ParamsAC, TemplateAC;
Params->getAssociatedConstraints(ParamsAC);
// C++2a[temp.arg.template]p3
// [...] In this comparison, if P is unconstrained, the constraints on A
// are not considered.
if (ParamsAC.empty())
return false;
Template->getAssociatedConstraints(TemplateAC);
bool IsParamAtLeastAsConstrained;
if (IsAtLeastAsConstrained(Param, ParamsAC, Template, TemplateAC,
IsParamAtLeastAsConstrained))
return true;
if (!IsParamAtLeastAsConstrained) {
Diag(Arg.getLocation(),
diag::err_template_template_parameter_not_at_least_as_constrained)
<< Template << Param << Arg.getSourceRange();
Diag(Param->getLocation(), diag::note_entity_declared_at) << Param;
Diag(Template->getLocation(), diag::note_entity_declared_at)
<< Template;
MaybeEmitAmbiguousAtomicConstraintsDiagnostic(Param, ParamsAC, Template,
TemplateAC);
return true;
}
return false;
}
// FIXME: Produce better diagnostics for deduction failures.
}
return !TemplateParameterListsAreEqual(Template->getTemplateParameters(),
Params,
true,
TPL_TemplateTemplateArgumentMatch,
Arg.getLocation());
}
/// Given a non-type template argument that refers to a
/// declaration and the type of its corresponding non-type template
/// parameter, produce an expression that properly refers to that
/// declaration.
ExprResult
Sema::BuildExpressionFromDeclTemplateArgument(const TemplateArgument &Arg,
QualType ParamType,
SourceLocation Loc) {
// C++ [temp.param]p8:
//
// A non-type template-parameter of type "array of T" or
// "function returning T" is adjusted to be of type "pointer to
// T" or "pointer to function returning T", respectively.
if (ParamType->isArrayType())
ParamType = Context.getArrayDecayedType(ParamType);
else if (ParamType->isFunctionType())
ParamType = Context.getPointerType(ParamType);
// For a NULL non-type template argument, return nullptr casted to the
// parameter's type.
if (Arg.getKind() == TemplateArgument::NullPtr) {
return ImpCastExprToType(
new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc),
ParamType,
ParamType->getAs<MemberPointerType>()
? CK_NullToMemberPointer
: CK_NullToPointer);
}
assert(Arg.getKind() == TemplateArgument::Declaration &&
"Only declaration template arguments permitted here");
ValueDecl *VD = Arg.getAsDecl();
CXXScopeSpec SS;
if (ParamType->isMemberPointerType()) {
// If this is a pointer to member, we need to use a qualified name to
// form a suitable pointer-to-member constant.
assert(VD->getDeclContext()->isRecord() &&
(isa<CXXMethodDecl>(VD) || isa<FieldDecl>(VD) ||
isa<IndirectFieldDecl>(VD)));
QualType ClassType
= Context.getTypeDeclType(cast<RecordDecl>(VD->getDeclContext()));
NestedNameSpecifier *Qualifier
= NestedNameSpecifier::Create(Context, nullptr, false,
ClassType.getTypePtr());
SS.MakeTrivial(Context, Qualifier, Loc);
}
ExprResult RefExpr = BuildDeclarationNameExpr(
SS, DeclarationNameInfo(VD->getDeclName(), Loc), VD);
if (RefExpr.isInvalid())
return ExprError();
// For a pointer, the argument declaration is the pointee. Take its address.
QualType ElemT(RefExpr.get()->getType()->getArrayElementTypeNoTypeQual(), 0);
if (ParamType->isPointerType() && !ElemT.isNull() &&
Context.hasSimilarType(ElemT, ParamType->getPointeeType())) {
// Decay an array argument if we want a pointer to its first element.
RefExpr = DefaultFunctionArrayConversion(RefExpr.get());
if (RefExpr.isInvalid())
return ExprError();
} else if (ParamType->isPointerType() || ParamType->isMemberPointerType()) {
// For any other pointer, take the address (or form a pointer-to-member).
RefExpr = CreateBuiltinUnaryOp(Loc, UO_AddrOf, RefExpr.get());
if (RefExpr.isInvalid())
return ExprError();
} else if (ParamType->isRecordType()) {
assert(isa<TemplateParamObjectDecl>(VD) &&
"arg for class template param not a template parameter object");
// No conversions apply in this case.
return RefExpr;
} else {
assert(ParamType->isReferenceType() &&
"unexpected type for decl template argument");
}
// At this point we should have the right value category.
assert(ParamType->isReferenceType() == RefExpr.get()->isLValue() &&
"value kind mismatch for non-type template argument");
// The type of the template parameter can differ from the type of the
// argument in various ways; convert it now if necessary.
QualType DestExprType = ParamType.getNonLValueExprType(Context);
if (!Context.hasSameType(RefExpr.get()->getType(), DestExprType)) {
CastKind CK;
QualType Ignored;
if (Context.hasSimilarType(RefExpr.get()->getType(), DestExprType) ||
IsFunctionConversion(RefExpr.get()->getType(), DestExprType, Ignored)) {
CK = CK_NoOp;
} else if (ParamType->isVoidPointerType() &&
RefExpr.get()->getType()->isPointerType()) {
CK = CK_BitCast;
} else {
// FIXME: Pointers to members can need conversion derived-to-base or
// base-to-derived conversions. We currently don't retain enough
// information to convert properly (we need to track a cast path or
// subobject number in the template argument).
llvm_unreachable(
"unexpected conversion required for non-type template argument");
}
RefExpr = ImpCastExprToType(RefExpr.get(), DestExprType, CK,
RefExpr.get()->getValueKind());
}
return RefExpr;
}
/// Construct a new expression that refers to the given
/// integral template argument with the given source-location
/// information.
///
/// This routine takes care of the mapping from an integral template
/// argument (which may have any integral type) to the appropriate
/// literal value.
ExprResult
Sema::BuildExpressionFromIntegralTemplateArgument(const TemplateArgument &Arg,
SourceLocation Loc) {
assert(Arg.getKind() == TemplateArgument::Integral &&
"Operation is only valid for integral template arguments");
QualType OrigT = Arg.getIntegralType();
// If this is an enum type that we're instantiating, we need to use an integer
// type the same size as the enumerator. We don't want to build an
// IntegerLiteral with enum type. The integer type of an enum type can be of
// any integral type with C++11 enum classes, make sure we create the right
// type of literal for it.
QualType T = OrigT;
if (const EnumType *ET = OrigT->getAs<EnumType>())
T = ET->getDecl()->getIntegerType();
Expr *E;
if (T->isAnyCharacterType()) {
CharacterLiteral::CharacterKind Kind;
if (T->isWideCharType())
Kind = CharacterLiteral::Wide;
else if (T->isChar8Type() && getLangOpts().Char8)
Kind = CharacterLiteral::UTF8;
else if (T->isChar16Type())
Kind = CharacterLiteral::UTF16;
else if (T->isChar32Type())
Kind = CharacterLiteral::UTF32;
else
Kind = CharacterLiteral::Ascii;
E = new (Context) CharacterLiteral(Arg.getAsIntegral().getZExtValue(),
Kind, T, Loc);
} else if (T->isBooleanType()) {
E = new (Context) CXXBoolLiteralExpr(Arg.getAsIntegral().getBoolValue(),
T, Loc);
} else if (T->isNullPtrType()) {
E = new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc);
} else {
E = IntegerLiteral::Create(Context, Arg.getAsIntegral(), T, Loc);
}
if (OrigT->isEnumeralType()) {
// FIXME: This is a hack. We need a better way to handle substituted
// non-type template parameters.
E = CStyleCastExpr::Create(Context, OrigT, VK_PRValue, CK_IntegralCast, E,
nullptr, CurFPFeatureOverrides(),
Context.getTrivialTypeSourceInfo(OrigT, Loc),
Loc, Loc);
}
return E;
}
/// Match two template parameters within template parameter lists.
static bool MatchTemplateParameterKind(Sema &S, NamedDecl *New, NamedDecl *Old,
bool Complain,
Sema::TemplateParameterListEqualKind Kind,
SourceLocation TemplateArgLoc) {
// Check the actual kind (type, non-type, template).
if (Old->getKind() != New->getKind()) {
if (Complain) {
unsigned NextDiag = diag::err_template_param_different_kind;
if (TemplateArgLoc.isValid()) {
S.Diag(TemplateArgLoc, diag::err_template_arg_template_params_mismatch);
NextDiag = diag::note_template_param_different_kind;
}
S.Diag(New->getLocation(), NextDiag)
<< (Kind != Sema::TPL_TemplateMatch);
S.Diag(Old->getLocation(), diag::note_template_prev_declaration)
<< (Kind != Sema::TPL_TemplateMatch);
}
return false;
}
// Check that both are parameter packs or neither are parameter packs.
// However, if we are matching a template template argument to a
// template template parameter, the template template parameter can have
// a parameter pack where the template template argument does not.
if (Old->isTemplateParameterPack() != New->isTemplateParameterPack() &&
!(Kind == Sema::TPL_TemplateTemplateArgumentMatch &&
Old->isTemplateParameterPack())) {
if (Complain) {
unsigned NextDiag = diag::err_template_parameter_pack_non_pack;
if (TemplateArgLoc.isValid()) {
S.Diag(TemplateArgLoc,
diag::err_template_arg_template_params_mismatch);
NextDiag = diag::note_template_parameter_pack_non_pack;
}
unsigned ParamKind = isa<TemplateTypeParmDecl>(New)? 0
: isa<NonTypeTemplateParmDecl>(New)? 1
: 2;
S.Diag(New->getLocation(), NextDiag)
<< ParamKind << New->isParameterPack();
S.Diag(Old->getLocation(), diag::note_template_parameter_pack_here)
<< ParamKind << Old->isParameterPack();
}
return false;
}
// For non-type template parameters, check the type of the parameter.
if (NonTypeTemplateParmDecl *OldNTTP
= dyn_cast<NonTypeTemplateParmDecl>(Old)) {
NonTypeTemplateParmDecl *NewNTTP = cast<NonTypeTemplateParmDecl>(New);
// If we are matching a template template argument to a template
// template parameter and one of the non-type template parameter types
// is dependent, then we must wait until template instantiation time
// to actually compare the arguments.
if (Kind != Sema::TPL_TemplateTemplateArgumentMatch ||
(!OldNTTP->getType()->isDependentType() &&
!NewNTTP->getType()->isDependentType()))
if (!S.Context.hasSameType(OldNTTP->getType(), NewNTTP->getType())) {
if (Complain) {
unsigned NextDiag = diag::err_template_nontype_parm_different_type;
if (TemplateArgLoc.isValid()) {
S.Diag(TemplateArgLoc,
diag::err_template_arg_template_params_mismatch);
NextDiag = diag::note_template_nontype_parm_different_type;
}
S.Diag(NewNTTP->getLocation(), NextDiag)
<< NewNTTP->getType()
<< (Kind != Sema::TPL_TemplateMatch);
S.Diag(OldNTTP->getLocation(),
diag::note_template_nontype_parm_prev_declaration)
<< OldNTTP->getType();
}
return false;
}
}
// For template template parameters, check the template parameter types.
// The template parameter lists of template template
// parameters must agree.
else if (TemplateTemplateParmDecl *OldTTP
= dyn_cast<TemplateTemplateParmDecl>(Old)) {
TemplateTemplateParmDecl *NewTTP = cast<TemplateTemplateParmDecl>(New);
if (!S.TemplateParameterListsAreEqual(NewTTP->getTemplateParameters(),
OldTTP->getTemplateParameters(),
Complain,
(Kind == Sema::TPL_TemplateMatch
? Sema::TPL_TemplateTemplateParmMatch
: Kind),
TemplateArgLoc))
return false;
} else if (Kind != Sema::TPL_TemplateTemplateArgumentMatch) {
const Expr *NewC = nullptr, *OldC = nullptr;
if (const auto *TC = cast<TemplateTypeParmDecl>(New)->getTypeConstraint())
NewC = TC->getImmediatelyDeclaredConstraint();
if (const auto *TC = cast<TemplateTypeParmDecl>(Old)->getTypeConstraint())
OldC = TC->getImmediatelyDeclaredConstraint();
auto Diagnose = [&] {
S.Diag(NewC ? NewC->getBeginLoc() : New->getBeginLoc(),
diag::err_template_different_type_constraint);
S.Diag(OldC ? OldC->getBeginLoc() : Old->getBeginLoc(),
diag::note_template_prev_declaration) << /*declaration*/0;
};
if (!NewC != !OldC) {
if (Complain)
Diagnose();
return false;
}
if (NewC) {
llvm::FoldingSetNodeID OldCID, NewCID;
OldC->Profile(OldCID, S.Context, /*Canonical=*/true);
NewC->Profile(NewCID, S.Context, /*Canonical=*/true);
if (OldCID != NewCID) {
if (Complain)
Diagnose();
return false;
}
}
}
return true;
}
/// Diagnose a known arity mismatch when comparing template argument
/// lists.
static
void DiagnoseTemplateParameterListArityMismatch(Sema &S,
TemplateParameterList *New,
TemplateParameterList *Old,
Sema::TemplateParameterListEqualKind Kind,
SourceLocation TemplateArgLoc) {
unsigned NextDiag = diag::err_template_param_list_different_arity;
if (TemplateArgLoc.isValid()) {
S.Diag(TemplateArgLoc, diag::err_template_arg_template_params_mismatch);
NextDiag = diag::note_template_param_list_different_arity;
}
S.Diag(New->getTemplateLoc(), NextDiag)
<< (New->size() > Old->size())
<< (Kind != Sema::TPL_TemplateMatch)
<< SourceRange(New->getTemplateLoc(), New->getRAngleLoc());
S.Diag(Old->getTemplateLoc(), diag::note_template_prev_declaration)
<< (Kind != Sema::TPL_TemplateMatch)
<< SourceRange(Old->getTemplateLoc(), Old->getRAngleLoc());
}
/// Determine whether the given template parameter lists are
/// equivalent.
///
/// \param New The new template parameter list, typically written in the
/// source code as part of a new template declaration.
///
/// \param Old The old template parameter list, typically found via
/// name lookup of the template declared with this template parameter
/// list.
///
/// \param Complain If true, this routine will produce a diagnostic if
/// the template parameter lists are not equivalent.
///
/// \param Kind describes how we are to match the template parameter lists.
///
/// \param TemplateArgLoc If this source location is valid, then we
/// are actually checking the template parameter list of a template
/// argument (New) against the template parameter list of its
/// corresponding template template parameter (Old). We produce
/// slightly different diagnostics in this scenario.
///
/// \returns True if the template parameter lists are equal, false
/// otherwise.
bool
Sema::TemplateParameterListsAreEqual(TemplateParameterList *New,
TemplateParameterList *Old,
bool Complain,
TemplateParameterListEqualKind Kind,
SourceLocation TemplateArgLoc) {
if (Old->size() != New->size() && Kind != TPL_TemplateTemplateArgumentMatch) {
if (Complain)
DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
TemplateArgLoc);
return false;
}
// C++0x [temp.arg.template]p3:
// A template-argument matches a template template-parameter (call it P)
// when each of the template parameters in the template-parameter-list of
// the template-argument's corresponding class template or alias template
// (call it A) matches the corresponding template parameter in the
// template-parameter-list of P. [...]
TemplateParameterList::iterator NewParm = New->begin();
TemplateParameterList::iterator NewParmEnd = New->end();
for (TemplateParameterList::iterator OldParm = Old->begin(),
OldParmEnd = Old->end();
OldParm != OldParmEnd; ++OldParm) {
if (Kind != TPL_TemplateTemplateArgumentMatch ||
!(*OldParm)->isTemplateParameterPack()) {
if (NewParm == NewParmEnd) {
if (Complain)
DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
TemplateArgLoc);
return false;
}
if (!MatchTemplateParameterKind(*this, *NewParm, *OldParm, Complain,
Kind, TemplateArgLoc))
return false;
++NewParm;
continue;
}
// C++0x [temp.arg.template]p3:
// [...] When P's template- parameter-list contains a template parameter
// pack (14.5.3), the template parameter pack will match zero or more
// template parameters or template parameter packs in the
// template-parameter-list of A with the same type and form as the
// template parameter pack in P (ignoring whether those template
// parameters are template parameter packs).
for (; NewParm != NewParmEnd; ++NewParm) {
if (!MatchTemplateParameterKind(*this, *NewParm, *OldParm, Complain,
Kind, TemplateArgLoc))
return false;
}
}
// Make sure we exhausted all of the arguments.
if (NewParm != NewParmEnd) {
if (Complain)
DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
TemplateArgLoc);
return false;
}
if (Kind != TPL_TemplateTemplateArgumentMatch) {
const Expr *NewRC = New->getRequiresClause();
const Expr *OldRC = Old->getRequiresClause();
auto Diagnose = [&] {
Diag(NewRC ? NewRC->getBeginLoc() : New->getTemplateLoc(),
diag::err_template_different_requires_clause);
Diag(OldRC ? OldRC->getBeginLoc() : Old->getTemplateLoc(),
diag::note_template_prev_declaration) << /*declaration*/0;
};
if (!NewRC != !OldRC) {
if (Complain)
Diagnose();
return false;
}
if (NewRC) {
llvm::FoldingSetNodeID OldRCID, NewRCID;
OldRC->Profile(OldRCID, Context, /*Canonical=*/true);
NewRC->Profile(NewRCID, Context, /*Canonical=*/true);
if (OldRCID != NewRCID) {
if (Complain)
Diagnose();
return false;
}
}
}
return true;
}
/// Check whether a template can be declared within this scope.
///
/// If the template declaration is valid in this scope, returns
/// false. Otherwise, issues a diagnostic and returns true.
bool
Sema::CheckTemplateDeclScope(Scope *S, TemplateParameterList *TemplateParams) {
if (!S)
return false;
// Find the nearest enclosing declaration scope.
while ((S->getFlags() & Scope::DeclScope) == 0 ||
(S->getFlags() & Scope::TemplateParamScope) != 0)
S = S->getParent();
// C++ [temp.pre]p6: [P2096]
// A template, explicit specialization, or partial specialization shall not
// have C linkage.
DeclContext *Ctx = S->getEntity();
if (Ctx && Ctx->isExternCContext()) {
Diag(TemplateParams->getTemplateLoc(), diag::err_template_linkage)
<< TemplateParams->getSourceRange();
if (const LinkageSpecDecl *LSD = Ctx->getExternCContext())
Diag(LSD->getExternLoc(), diag::note_extern_c_begins_here);
return true;
}
Ctx = Ctx ? Ctx->getRedeclContext() : nullptr;
// C++ [temp]p2:
// A template-declaration can appear only as a namespace scope or
// class scope declaration.
// C++ [temp.expl.spec]p3:
// An explicit specialization may be declared in any scope in which the
// corresponding primary template may be defined.
// C++ [temp.class.spec]p6: [P2096]
// A partial specialization may be declared in any scope in which the
// corresponding primary template may be defined.
if (Ctx) {
if (Ctx->isFileContext())
return false;
if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Ctx)) {
// C++ [temp.mem]p2:
// A local class shall not have member templates.
if (RD->isLocalClass())
return Diag(TemplateParams->getTemplateLoc(),
diag::err_template_inside_local_class)
<< TemplateParams->getSourceRange();
else
return false;
}
}
return Diag(TemplateParams->getTemplateLoc(),
diag::err_template_outside_namespace_or_class_scope)
<< TemplateParams->getSourceRange();
}
/// Determine what kind of template specialization the given declaration
/// is.
static TemplateSpecializationKind getTemplateSpecializationKind(Decl *D) {
if (!D)
return TSK_Undeclared;
if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D))
return Record->getTemplateSpecializationKind();
if (FunctionDecl *Function = dyn_cast<FunctionDecl>(D))
return Function->getTemplateSpecializationKind();
if (VarDecl *Var = dyn_cast<VarDecl>(D))
return Var->getTemplateSpecializationKind();
return TSK_Undeclared;
}
/// Check whether a specialization is well-formed in the current
/// context.
///
/// This routine determines whether a template specialization can be declared
/// in the current context (C++ [temp.expl.spec]p2).
///
/// \param S the semantic analysis object for which this check is being
/// performed.
///
/// \param Specialized the entity being specialized or instantiated, which
/// may be a kind of template (class template, function template, etc.) or
/// a member of a class template (member function, static data member,
/// member class).
///
/// \param PrevDecl the previous declaration of this entity, if any.
///
/// \param Loc the location of the explicit specialization or instantiation of
/// this entity.
///
/// \param IsPartialSpecialization whether this is a partial specialization of
/// a class template.
///
/// \returns true if there was an error that we cannot recover from, false
/// otherwise.
static bool CheckTemplateSpecializationScope(Sema &S,
NamedDecl *Specialized,
NamedDecl *PrevDecl,
SourceLocation Loc,
bool IsPartialSpecialization) {
// Keep these "kind" numbers in sync with the %select statements in the
// various diagnostics emitted by this routine.
int EntityKind = 0;
if (isa<ClassTemplateDecl>(Specialized))
EntityKind = IsPartialSpecialization? 1 : 0;
else if (isa<VarTemplateDecl>(Specialized))
EntityKind = IsPartialSpecialization ? 3 : 2;
else if (isa<FunctionTemplateDecl>(Specialized))
EntityKind = 4;
else if (isa<CXXMethodDecl>(Specialized))
EntityKind = 5;
else if (isa<VarDecl>(Specialized))
EntityKind = 6;
else if (isa<RecordDecl>(Specialized))
EntityKind = 7;
else if (isa<EnumDecl>(Specialized) && S.getLangOpts().CPlusPlus11)
EntityKind = 8;
else {
S.Diag(Loc, diag::err_template_spec_unknown_kind)
<< S.getLangOpts().CPlusPlus11;
S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
return true;
}
// C++ [temp.expl.spec]p2:
// An explicit specialization may be declared in any scope in which
// the corresponding primary template may be defined.
if (S.CurContext->getRedeclContext()->isFunctionOrMethod()) {
S.Diag(Loc, diag::err_template_spec_decl_function_scope)
<< Specialized;
return true;
}
// C++ [temp.class.spec]p6:
// A class template partial specialization may be declared in any
// scope in which the primary template may be defined.
DeclContext *SpecializedContext =
Specialized->getDeclContext()->getRedeclContext();
DeclContext *DC = S.CurContext->getRedeclContext();
// Make sure that this redeclaration (or definition) occurs in the same
// scope or an enclosing namespace.
if (!(DC->isFileContext() ? DC->Encloses(SpecializedContext)
: DC->Equals(SpecializedContext))) {
if (isa<TranslationUnitDecl>(SpecializedContext))
S.Diag(Loc, diag::err_template_spec_redecl_global_scope)
<< EntityKind << Specialized;
else {
auto *ND = cast<NamedDecl>(SpecializedContext);
int Diag = diag::err_template_spec_redecl_out_of_scope;
if (S.getLangOpts().MicrosoftExt && !DC->isRecord())
Diag = diag::ext_ms_template_spec_redecl_out_of_scope;
S.Diag(Loc, Diag) << EntityKind << Specialized
<< ND << isa<CXXRecordDecl>(ND);
}
S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
// Don't allow specializing in the wrong class during error recovery.
// Otherwise, things can go horribly wrong.
if (DC->isRecord())
return true;
}
return false;
}
static SourceRange findTemplateParameterInType(unsigned Depth, Expr *E) {
if (!E->isTypeDependent())
return SourceLocation();
DependencyChecker Checker(Depth, /*IgnoreNonTypeDependent*/true);
Checker.TraverseStmt(E);
if (Checker.MatchLoc.isInvalid())
return E->getSourceRange();
return Checker.MatchLoc;
}
static SourceRange findTemplateParameter(unsigned Depth, TypeLoc TL) {
if (!TL.getType()->isDependentType())
return SourceLocation();
DependencyChecker Checker(Depth, /*IgnoreNonTypeDependent*/true);
Checker.TraverseTypeLoc(TL);
if (Checker.MatchLoc.isInvalid())
return TL.getSourceRange();
return Checker.MatchLoc;
}
/// Subroutine of Sema::CheckTemplatePartialSpecializationArgs
/// that checks non-type template partial specialization arguments.
static bool CheckNonTypeTemplatePartialSpecializationArgs(
Sema &S, SourceLocation TemplateNameLoc, NonTypeTemplateParmDecl *Param,
const TemplateArgument *Args, unsigned NumArgs, bool IsDefaultArgument) {
for (unsigned I = 0; I != NumArgs; ++I) {
if (Args[I].getKind() == TemplateArgument::Pack) {
if (CheckNonTypeTemplatePartialSpecializationArgs(
S, TemplateNameLoc, Param, Args[I].pack_begin(),
Args[I].pack_size(), IsDefaultArgument))
return true;
continue;
}
if (Args[I].getKind() != TemplateArgument::Expression)
continue;
Expr *ArgExpr = Args[I].getAsExpr();
// We can have a pack expansion of any of the bullets below.
if (PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(ArgExpr))
ArgExpr = Expansion->getPattern();
// Strip off any implicit casts we added as part of type checking.
while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgExpr))
ArgExpr = ICE->getSubExpr();
// C++ [temp.class.spec]p8:
// A non-type argument is non-specialized if it is the name of a
// non-type parameter. All other non-type arguments are
// specialized.
//
// Below, we check the two conditions that only apply to
// specialized non-type arguments, so skip any non-specialized
// arguments.
if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ArgExpr))
if (isa<NonTypeTemplateParmDecl>(DRE->getDecl()))
continue;
// C++ [temp.class.spec]p9:
// Within the argument list of a class template partial
// specialization, the following restrictions apply:
// -- A partially specialized non-type argument expression
// shall not involve a template parameter of the partial
// specialization except when the argument expression is a
// simple identifier.
// -- The type of a template parameter corresponding to a
// specialized non-type argument shall not be dependent on a
// parameter of the specialization.
// DR1315 removes the first bullet, leaving an incoherent set of rules.
// We implement a compromise between the original rules and DR1315:
// -- A specialized non-type template argument shall not be
// type-dependent and the corresponding template parameter
// shall have a non-dependent type.
SourceRange ParamUseRange =
findTemplateParameterInType(Param->getDepth(), ArgExpr);
if (ParamUseRange.isValid()) {
if (IsDefaultArgument) {
S.Diag(TemplateNameLoc,
diag::err_dependent_non_type_arg_in_partial_spec);
S.Diag(ParamUseRange.getBegin(),
diag::note_dependent_non_type_default_arg_in_partial_spec)
<< ParamUseRange;
} else {
S.Diag(ParamUseRange.getBegin(),
diag::err_dependent_non_type_arg_in_partial_spec)
<< ParamUseRange;
}
return true;
}
ParamUseRange = findTemplateParameter(
Param->getDepth(), Param->getTypeSourceInfo()->getTypeLoc());
if (ParamUseRange.isValid()) {
S.Diag(IsDefaultArgument ? TemplateNameLoc : ArgExpr->getBeginLoc(),
diag::err_dependent_typed_non_type_arg_in_partial_spec)
<< Param->getType();
S.Diag(Param->getLocation(), diag::note_template_param_here)
<< (IsDefaultArgument ? ParamUseRange : SourceRange())
<< ParamUseRange;
return true;
}
}
return false;
}
/// Check the non-type template arguments of a class template
/// partial specialization according to C++ [temp.class.spec]p9.
///
/// \param TemplateNameLoc the location of the template name.
/// \param PrimaryTemplate the template parameters of the primary class
/// template.
/// \param NumExplicit the number of explicitly-specified template arguments.
/// \param TemplateArgs the template arguments of the class template
/// partial specialization.
///
/// \returns \c true if there was an error, \c false otherwise.
bool Sema::CheckTemplatePartialSpecializationArgs(
SourceLocation TemplateNameLoc, TemplateDecl *PrimaryTemplate,
unsigned NumExplicit, ArrayRef<TemplateArgument> TemplateArgs) {
// We have to be conservative when checking a template in a dependent
// context.
if (PrimaryTemplate->getDeclContext()->isDependentContext())
return false;
TemplateParameterList *TemplateParams =
PrimaryTemplate->getTemplateParameters();
for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
NonTypeTemplateParmDecl *Param
= dyn_cast<NonTypeTemplateParmDecl>(TemplateParams->getParam(I));
if (!Param)
continue;
if (CheckNonTypeTemplatePartialSpecializationArgs(*this, TemplateNameLoc,
Param, &TemplateArgs[I],
1, I >= NumExplicit))
return true;
}
return false;
}
DeclResult Sema::ActOnClassTemplateSpecialization(
Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
SourceLocation ModulePrivateLoc, CXXScopeSpec &SS,
TemplateIdAnnotation &TemplateId, const ParsedAttributesView &Attr,
MultiTemplateParamsArg TemplateParameterLists, SkipBodyInfo *SkipBody) {
assert(TUK != TUK_Reference && "References are not specializations");
// NOTE: KWLoc is the location of the tag keyword. This will instead
// store the location of the outermost template keyword in the declaration.
SourceLocation TemplateKWLoc = TemplateParameterLists.size() > 0
? TemplateParameterLists[0]->getTemplateLoc() : KWLoc;
SourceLocation TemplateNameLoc = TemplateId.TemplateNameLoc;
SourceLocation LAngleLoc = TemplateId.LAngleLoc;
SourceLocation RAngleLoc = TemplateId.RAngleLoc;
// Find the class template we're specializing
TemplateName Name = TemplateId.Template.get();
ClassTemplateDecl *ClassTemplate
= dyn_cast_or_null<ClassTemplateDecl>(Name.getAsTemplateDecl());
if (!ClassTemplate) {
Diag(TemplateNameLoc, diag::err_not_class_template_specialization)
<< (Name.getAsTemplateDecl() &&
isa<TemplateTemplateParmDecl>(Name.getAsTemplateDecl()));
return true;
}
bool isMemberSpecialization = false;
bool isPartialSpecialization = false;
// Check the validity of the template headers that introduce this
// template.
// FIXME: We probably shouldn't complain about these headers for
// friend declarations.
bool Invalid = false;
TemplateParameterList *TemplateParams =
MatchTemplateParametersToScopeSpecifier(
KWLoc, TemplateNameLoc, SS, &TemplateId,
TemplateParameterLists, TUK == TUK_Friend, isMemberSpecialization,
Invalid);
if (Invalid)
return true;
// Check that we can declare a template specialization here.
if (TemplateParams && CheckTemplateDeclScope(S, TemplateParams))
return true;
if (TemplateParams && TemplateParams->size() > 0) {
isPartialSpecialization = true;
if (TUK == TUK_Friend) {
Diag(KWLoc, diag::err_partial_specialization_friend)
<< SourceRange(LAngleLoc, RAngleLoc);
return true;
}
// C++ [temp.class.spec]p10:
// The template parameter list of a specialization shall not
// contain default template argument values.
for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
Decl *Param = TemplateParams->getParam(I);
if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param)) {
if (TTP->hasDefaultArgument()) {
Diag(TTP->getDefaultArgumentLoc(),
diag::err_default_arg_in_partial_spec);
TTP->removeDefaultArgument();
}
} else if (NonTypeTemplateParmDecl *NTTP
= dyn_cast<NonTypeTemplateParmDecl>(Param)) {
if (Expr *DefArg = NTTP->getDefaultArgument()) {
Diag(NTTP->getDefaultArgumentLoc(),
diag::err_default_arg_in_partial_spec)
<< DefArg->getSourceRange();
NTTP->removeDefaultArgument();
}
} else {
TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(Param);
if (TTP->hasDefaultArgument()) {
Diag(TTP->getDefaultArgument().getLocation(),
diag::err_default_arg_in_partial_spec)
<< TTP->getDefaultArgument().getSourceRange();
TTP->removeDefaultArgument();
}
}
}
} else if (TemplateParams) {
if (TUK == TUK_Friend)
Diag(KWLoc, diag::err_template_spec_friend)
<< FixItHint::CreateRemoval(
SourceRange(TemplateParams->getTemplateLoc(),
TemplateParams->getRAngleLoc()))
<< SourceRange(LAngleLoc, RAngleLoc);
} else {
assert(TUK == TUK_Friend && "should have a 'template<>' for this decl");
}
// Check that the specialization uses the same tag kind as the
// original template.
TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
assert(Kind != TTK_Enum && "Invalid enum tag in class template spec!");
if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
Kind, TUK == TUK_Definition, KWLoc,
ClassTemplate->getIdentifier())) {
Diag(KWLoc, diag::err_use_with_wrong_tag)
<< ClassTemplate
<< FixItHint::CreateReplacement(KWLoc,
ClassTemplate->getTemplatedDecl()->getKindName());
Diag(ClassTemplate->getTemplatedDecl()->getLocation(),
diag::note_previous_use);
Kind = ClassTemplate->getTemplatedDecl()->getTagKind();
}
// Translate the parser's template argument list in our AST format.
TemplateArgumentListInfo TemplateArgs =
makeTemplateArgumentListInfo(*this, TemplateId);
// Check for unexpanded parameter packs in any of the template arguments.
for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
if (DiagnoseUnexpandedParameterPack(TemplateArgs[I],
UPPC_PartialSpecialization))
return true;
// Check that the template argument list is well-formed for this
// template.
SmallVector<TemplateArgument, 4> Converted;
if (CheckTemplateArgumentList(ClassTemplate, TemplateNameLoc,
TemplateArgs, false, Converted,
/*UpdateArgsWithConversions=*/true))
return true;
// Find the class template (partial) specialization declaration that
// corresponds to these arguments.
if (isPartialSpecialization) {
if (CheckTemplatePartialSpecializationArgs(TemplateNameLoc, ClassTemplate,
TemplateArgs.size(), Converted))
return true;
// FIXME: Move this to CheckTemplatePartialSpecializationArgs so we
// also do it during instantiation.
if (!Name.isDependent() &&
!TemplateSpecializationType::anyDependentTemplateArguments(TemplateArgs,
Converted)) {
Diag(TemplateNameLoc, diag::err_partial_spec_fully_specialized)
<< ClassTemplate->getDeclName();
isPartialSpecialization = false;
}
}
void *InsertPos = nullptr;
ClassTemplateSpecializationDecl *PrevDecl = nullptr;
if (isPartialSpecialization)
PrevDecl = ClassTemplate->findPartialSpecialization(Converted,
TemplateParams,
InsertPos);
else
PrevDecl = ClassTemplate->findSpecialization(Converted, InsertPos);
ClassTemplateSpecializationDecl *Specialization = nullptr;
// Check whether we can declare a class template specialization in
// the current scope.
if (TUK != TUK_Friend &&
CheckTemplateSpecializationScope(*this, ClassTemplate, PrevDecl,
TemplateNameLoc,
isPartialSpecialization))
return true;
// The canonical type
QualType CanonType;
if (isPartialSpecialization) {
// Build the canonical type that describes the converted template
// arguments of the class template partial specialization.
TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
CanonType = Context.getTemplateSpecializationType(CanonTemplate,
Converted);
if (Context.hasSameType(CanonType,
ClassTemplate->getInjectedClassNameSpecialization()) &&
(!Context.getLangOpts().CPlusPlus20 ||
!TemplateParams->hasAssociatedConstraints())) {
// C++ [temp.class.spec]p9b3:
//
// -- The argument list of the specialization shall not be identical
// to the implicit argument list of the primary template.
//
// This rule has since been removed, because it's redundant given DR1495,
// but we keep it because it produces better diagnostics and recovery.
Diag(TemplateNameLoc, diag::err_partial_spec_args_match_primary_template)
<< /*class template*/0 << (TUK == TUK_Definition)
<< FixItHint::CreateRemoval(SourceRange(LAngleLoc, RAngleLoc));
return CheckClassTemplate(S, TagSpec, TUK, KWLoc, SS,
ClassTemplate->getIdentifier(),
TemplateNameLoc,
Attr,
TemplateParams,
AS_none, /*ModulePrivateLoc=*/SourceLocation(),
/*FriendLoc*/SourceLocation(),
TemplateParameterLists.size() - 1,
TemplateParameterLists.data());
}
// Create a new class template partial specialization declaration node.
ClassTemplatePartialSpecializationDecl *PrevPartial
= cast_or_null<ClassTemplatePartialSpecializationDecl>(PrevDecl);
ClassTemplatePartialSpecializationDecl *Partial
= ClassTemplatePartialSpecializationDecl::Create(Context, Kind,
ClassTemplate->getDeclContext(),
KWLoc, TemplateNameLoc,
TemplateParams,
ClassTemplate,
Converted,
TemplateArgs,
CanonType,
PrevPartial);
SetNestedNameSpecifier(*this, Partial, SS);
if (TemplateParameterLists.size() > 1 && SS.isSet()) {
Partial->setTemplateParameterListsInfo(
Context, TemplateParameterLists.drop_back(1));
}
if (!PrevPartial)
ClassTemplate->AddPartialSpecialization(Partial, InsertPos);
Specialization = Partial;
// If we are providing an explicit specialization of a member class
// template specialization, make a note of that.
if (PrevPartial && PrevPartial->getInstantiatedFromMember())
PrevPartial->setMemberSpecialization();
CheckTemplatePartialSpecialization(Partial);
} else {
// Create a new class template specialization declaration node for
// this explicit specialization or friend declaration.
Specialization
= ClassTemplateSpecializationDecl::Create(Context, Kind,
ClassTemplate->getDeclContext(),
KWLoc, TemplateNameLoc,
ClassTemplate,
Converted,
PrevDecl);
SetNestedNameSpecifier(*this, Specialization, SS);
if (TemplateParameterLists.size() > 0) {
Specialization->setTemplateParameterListsInfo(Context,
TemplateParameterLists);
}
if (!PrevDecl)
ClassTemplate->AddSpecialization(Specialization, InsertPos);
if (CurContext->isDependentContext()) {
TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
CanonType = Context.getTemplateSpecializationType(
CanonTemplate, Converted);
} else {
CanonType = Context.getTypeDeclType(Specialization);
}
}
// C++ [temp.expl.spec]p6:
// If a template, a member template or the member of a class template is
// explicitly specialized then that specialization shall be declared
// before the first use of that specialization that would cause an implicit
// instantiation to take place, in every translation unit in which such a
// use occurs; no diagnostic is required.
if (PrevDecl && PrevDecl->getPointOfInstantiation().isValid()) {
bool Okay = false;
for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
// Is there any previous explicit specialization declaration?
if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
Okay = true;
break;
}
}
if (!Okay) {
SourceRange Range(TemplateNameLoc, RAngleLoc);
Diag(TemplateNameLoc, diag::err_specialization_after_instantiation)
<< Context.getTypeDeclType(Specialization) << Range;
Diag(PrevDecl->getPointOfInstantiation(),
diag::note_instantiation_required_here)
<< (PrevDecl->getTemplateSpecializationKind()
!= TSK_ImplicitInstantiation);
return true;
}
}
// If this is not a friend, note that this is an explicit specialization.
if (TUK != TUK_Friend)
Specialization->setSpecializationKind(TSK_ExplicitSpecialization);
// Check that this isn't a redefinition of this specialization.
if (TUK == TUK_Definition) {
RecordDecl *Def = Specialization->getDefinition();
NamedDecl *Hidden = nullptr;
if (Def && SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
SkipBody->ShouldSkip = true;
SkipBody->Previous = Def;
makeMergedDefinitionVisible(Hidden);
} else if (Def) {
SourceRange Range(TemplateNameLoc, RAngleLoc);
Diag(TemplateNameLoc, diag::err_redefinition) << Specialization << Range;
Diag(Def->getLocation(), diag::note_previous_definition);
Specialization->setInvalidDecl();
return true;
}
}
ProcessDeclAttributeList(S, Specialization, Attr);
// Add alignment attributes if necessary; these attributes are checked when
// the ASTContext lays out the structure.
if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
AddAlignmentAttributesForRecord(Specialization);
AddMsStructLayoutForRecord(Specialization);
}
if (ModulePrivateLoc.isValid())
Diag(Specialization->getLocation(), diag::err_module_private_specialization)
<< (isPartialSpecialization? 1 : 0)
<< FixItHint::CreateRemoval(ModulePrivateLoc);
// Build the fully-sugared type for this class template
// specialization as the user wrote in the specialization
// itself. This means that we'll pretty-print the type retrieved
// from the specialization's declaration the way that the user
// actually wrote the specialization, rather than formatting the
// name based on the "canonical" representation used to store the
// template arguments in the specialization.
TypeSourceInfo *WrittenTy
= Context.getTemplateSpecializationTypeInfo(Name, TemplateNameLoc,
TemplateArgs, CanonType);
if (TUK != TUK_Friend) {
Specialization->setTypeAsWritten(WrittenTy);
Specialization->setTemplateKeywordLoc(TemplateKWLoc);
}
// C++ [temp.expl.spec]p9:
// A template explicit specialization is in the scope of the
// namespace in which the template was defined.
//
// We actually implement this paragraph where we set the semantic
// context (in the creation of the ClassTemplateSpecializationDecl),
// but we also maintain the lexical context where the actual
// definition occurs.
Specialization->setLexicalDeclContext(CurContext);
// We may be starting the definition of this specialization.
if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
Specialization->startDefinition();
if (TUK == TUK_Friend) {
FriendDecl *Friend = FriendDecl::Create(Context, CurContext,
TemplateNameLoc,
WrittenTy,
/*FIXME:*/KWLoc);
Friend->setAccess(AS_public);
CurContext->addDecl(Friend);
} else {
// Add the specialization into its lexical context, so that it can
// be seen when iterating through the list of declarations in that
// context. However, specializations are not found by name lookup.
CurContext->addDecl(Specialization);
}
if (SkipBody && SkipBody->ShouldSkip)
return SkipBody->Previous;
return Specialization;
}
Decl *Sema::ActOnTemplateDeclarator(Scope *S,
MultiTemplateParamsArg TemplateParameterLists,
Declarator &D) {
Decl *NewDecl = HandleDeclarator(S, D, TemplateParameterLists);
ActOnDocumentableDecl(NewDecl);
return NewDecl;
}
Decl *Sema::ActOnConceptDefinition(Scope *S,
MultiTemplateParamsArg TemplateParameterLists,
IdentifierInfo *Name, SourceLocation NameLoc,
Expr *ConstraintExpr) {
DeclContext *DC = CurContext;
if (!DC->getRedeclContext()->isFileContext()) {
Diag(NameLoc,
diag::err_concept_decls_may_only_appear_in_global_namespace_scope);
return nullptr;
}
if (TemplateParameterLists.size() > 1) {
Diag(NameLoc, diag::err_concept_extra_headers);
return nullptr;
}
if (TemplateParameterLists.front()->size() == 0) {
Diag(NameLoc, diag::err_concept_no_parameters);
return nullptr;
}
if (DiagnoseUnexpandedParameterPack(ConstraintExpr))
return nullptr;
ConceptDecl *NewDecl = ConceptDecl::Create(Context, DC, NameLoc, Name,
TemplateParameterLists.front(),
ConstraintExpr);
if (NewDecl->hasAssociatedConstraints()) {
// C++2a [temp.concept]p4:
// A concept shall not have associated constraints.
Diag(NameLoc, diag::err_concept_no_associated_constraints);
NewDecl->setInvalidDecl();
}
// Check for conflicting previous declaration.
DeclarationNameInfo NameInfo(NewDecl->getDeclName(), NameLoc);
LookupResult Previous(*this, NameInfo, LookupOrdinaryName,
ForVisibleRedeclaration);
LookupName(Previous, S);
FilterLookupForScope(Previous, DC, S, /*ConsiderLinkage=*/false,
/*AllowInlineNamespace*/false);
if (!Previous.empty()) {
auto *Old = Previous.getRepresentativeDecl();
Diag(NameLoc, isa<ConceptDecl>(Old) ? diag::err_redefinition :
diag::err_redefinition_different_kind) << NewDecl->getDeclName();
Diag(Old->getLocation(), diag::note_previous_definition);
}
ActOnDocumentableDecl(NewDecl);
PushOnScopeChains(NewDecl, S);
return NewDecl;
}
/// \brief Strips various properties off an implicit instantiation
/// that has just been explicitly specialized.
static void StripImplicitInstantiation(NamedDecl *D) {
D->dropAttr<DLLImportAttr>();
D->dropAttr<DLLExportAttr>();
if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
FD->setInlineSpecified(false);
}
/// Compute the diagnostic location for an explicit instantiation
// declaration or definition.
static SourceLocation DiagLocForExplicitInstantiation(
NamedDecl* D, SourceLocation PointOfInstantiation) {
// Explicit instantiations following a specialization have no effect and
// hence no PointOfInstantiation. In that case, walk decl backwards
// until a valid name loc is found.
SourceLocation PrevDiagLoc = PointOfInstantiation;
for (Decl *Prev = D; Prev && !PrevDiagLoc.isValid();
Prev = Prev->getPreviousDecl()) {
PrevDiagLoc = Prev->getLocation();
}
assert(PrevDiagLoc.isValid() &&
"Explicit instantiation without point of instantiation?");
return PrevDiagLoc;
}
/// Diagnose cases where we have an explicit template specialization
/// before/after an explicit template instantiation, producing diagnostics
/// for those cases where they are required and determining whether the
/// new specialization/instantiation will have any effect.
///
/// \param NewLoc the location of the new explicit specialization or
/// instantiation.
///
/// \param NewTSK the kind of the new explicit specialization or instantiation.
///
/// \param PrevDecl the previous declaration of the entity.
///
/// \param PrevTSK the kind of the old explicit specialization or instantiatin.
///
/// \param PrevPointOfInstantiation if valid, indicates where the previous
/// declaration was instantiated (either implicitly or explicitly).
///
/// \param HasNoEffect will be set to true to indicate that the new
/// specialization or instantiation has no effect and should be ignored.
///
/// \returns true if there was an error that should prevent the introduction of
/// the new declaration into the AST, false otherwise.
bool
Sema::CheckSpecializationInstantiationRedecl(SourceLocation NewLoc,
TemplateSpecializationKind NewTSK,
NamedDecl *PrevDecl,
TemplateSpecializationKind PrevTSK,
SourceLocation PrevPointOfInstantiation,
bool &HasNoEffect) {
HasNoEffect = false;
switch (NewTSK) {
case TSK_Undeclared:
case TSK_ImplicitInstantiation:
assert(
(PrevTSK == TSK_Undeclared || PrevTSK == TSK_ImplicitInstantiation) &&
"previous declaration must be implicit!");
return false;
case TSK_ExplicitSpecialization:
switch (PrevTSK) {
case TSK_Undeclared:
case TSK_ExplicitSpecialization:
// Okay, we're just specializing something that is either already
// explicitly specialized or has merely been mentioned without any
// instantiation.
return false;
case TSK_ImplicitInstantiation:
if (PrevPointOfInstantiation.isInvalid()) {
// The declaration itself has not actually been instantiated, so it is
// still okay to specialize it.
StripImplicitInstantiation(PrevDecl);
return false;
}
// Fall through
LLVM_FALLTHROUGH;
case TSK_ExplicitInstantiationDeclaration:
case TSK_ExplicitInstantiationDefinition:
assert((PrevTSK == TSK_ImplicitInstantiation ||
PrevPointOfInstantiation.isValid()) &&
"Explicit instantiation without point of instantiation?");
// C++ [temp.expl.spec]p6:
// If a template, a member template or the member of a class template
// is explicitly specialized then that specialization shall be declared
// before the first use of that specialization that would cause an
// implicit instantiation to take place, in every translation unit in
// which such a use occurs; no diagnostic is required.
for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
// Is there any previous explicit specialization declaration?
if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization)
return false;
}
Diag(NewLoc, diag::err_specialization_after_instantiation)
<< PrevDecl;
Diag(PrevPointOfInstantiation, diag::note_instantiation_required_here)
<< (PrevTSK != TSK_ImplicitInstantiation);
return true;
}
llvm_unreachable("The switch over PrevTSK must be exhaustive.");
case TSK_ExplicitInstantiationDeclaration:
switch (PrevTSK) {
case TSK_ExplicitInstantiationDeclaration:
// This explicit instantiation declaration is redundant (that's okay).
HasNoEffect = true;
return false;
case TSK_Undeclared:
case TSK_ImplicitInstantiation:
// We're explicitly instantiating something that may have already been
// implicitly instantiated; that's fine.
return false;
case TSK_ExplicitSpecialization:
// C++0x [temp.explicit]p4:
// For a given set of template parameters, if an explicit instantiation
// of a template appears after a declaration of an explicit
// specialization for that template, the explicit instantiation has no
// effect.
HasNoEffect = true;
return false;
case TSK_ExplicitInstantiationDefinition:
// C++0x [temp.explicit]p10:
// If an entity is the subject of both an explicit instantiation
// declaration and an explicit instantiation definition in the same
// translation unit, the definition shall follow the declaration.
Diag(NewLoc,
diag::err_explicit_instantiation_declaration_after_definition);
// Explicit instantiations following a specialization have no effect and
// hence no PrevPointOfInstantiation. In that case, walk decl backwards
// until a valid name loc is found.
Diag(DiagLocForExplicitInstantiation(PrevDecl, PrevPointOfInstantiation),
diag::note_explicit_instantiation_definition_here);
HasNoEffect = true;
return false;
}
llvm_unreachable("Unexpected TemplateSpecializationKind!");
case TSK_ExplicitInstantiationDefinition:
switch (PrevTSK) {
case TSK_Undeclared:
case TSK_ImplicitInstantiation:
// We're explicitly instantiating something that may have already been
// implicitly instantiated; that's fine.
return false;
case TSK_ExplicitSpecialization:
// C++ DR 259, C++0x [temp.explicit]p4:
// For a given set of template parameters, if an explicit
// instantiation of a template appears after a declaration of
// an explicit specialization for that template, the explicit
// instantiation has no effect.
Diag(NewLoc, diag::warn_explicit_instantiation_after_specialization)
<< PrevDecl;
Diag(PrevDecl->getLocation(),
diag::note_previous_template_specialization);
HasNoEffect = true;
return false;
case TSK_ExplicitInstantiationDeclaration:
// We're explicitly instantiating a definition for something for which we
// were previously asked to suppress instantiations. That's fine.
// C++0x [temp.explicit]p4:
// For a given set of template parameters, if an explicit instantiation
// of a template appears after a declaration of an explicit
// specialization for that template, the explicit instantiation has no
// effect.
for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
// Is there any previous explicit specialization declaration?
if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
HasNoEffect = true;
break;
}
}
return false;
case TSK_ExplicitInstantiationDefinition:
// C++0x [temp.spec]p5:
// For a given template and a given set of template-arguments,
// - an explicit instantiation definition shall appear at most once
// in a program,
// MSVCCompat: MSVC silently ignores duplicate explicit instantiations.
Diag(NewLoc, (getLangOpts().MSVCCompat)
? diag::ext_explicit_instantiation_duplicate
: diag::err_explicit_instantiation_duplicate)
<< PrevDecl;
Diag(DiagLocForExplicitInstantiation(PrevDecl, PrevPointOfInstantiation),
diag::note_previous_explicit_instantiation);
HasNoEffect = true;
return false;
}
}
llvm_unreachable("Missing specialization/instantiation case?");
}
/// Perform semantic analysis for the given dependent function
/// template specialization.
///
/// The only possible way to get a dependent function template specialization
/// is with a friend declaration, like so:
///
/// \code
/// template \<class T> void foo(T);
/// template \<class T> class A {
/// friend void foo<>(T);
/// };
/// \endcode
///
/// There really isn't any useful analysis we can do here, so we
/// just store the information.
bool
Sema::CheckDependentFunctionTemplateSpecialization(FunctionDecl *FD,
const TemplateArgumentListInfo &ExplicitTemplateArgs,
LookupResult &Previous) {
// Remove anything from Previous that isn't a function template in
// the correct context.
DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
LookupResult::Filter F = Previous.makeFilter();
enum DiscardReason { NotAFunctionTemplate, NotAMemberOfEnclosing };
SmallVector<std::pair<DiscardReason, Decl *>, 8> DiscardedCandidates;
while (F.hasNext()) {
NamedDecl *D = F.next()->getUnderlyingDecl();
if (!isa<FunctionTemplateDecl>(D)) {
F.erase();
DiscardedCandidates.push_back(std::make_pair(NotAFunctionTemplate, D));
continue;
}
if (!FDLookupContext->InEnclosingNamespaceSetOf(
D->getDeclContext()->getRedeclContext())) {
F.erase();
DiscardedCandidates.push_back(std::make_pair(NotAMemberOfEnclosing, D));
continue;
}
}
F.done();
if (Previous.empty()) {
Diag(FD->getLocation(),
diag::err_dependent_function_template_spec_no_match);
for (auto &P : DiscardedCandidates)
Diag(P.second->getLocation(),
diag::note_dependent_function_template_spec_discard_reason)
<< P.first;
return true;
}
FD->setDependentTemplateSpecialization(Context, Previous.asUnresolvedSet(),
ExplicitTemplateArgs);
return false;
}
/// Perform semantic analysis for the given function template
/// specialization.
///
/// This routine performs all of the semantic analysis required for an
/// explicit function template specialization. On successful completion,
/// the function declaration \p FD will become a function template
/// specialization.
///
/// \param FD the function declaration, which will be updated to become a
/// function template specialization.
///
/// \param ExplicitTemplateArgs the explicitly-provided template arguments,
/// if any. Note that this may be valid info even when 0 arguments are
/// explicitly provided as in, e.g., \c void sort<>(char*, char*);
/// as it anyway contains info on the angle brackets locations.
///
/// \param Previous the set of declarations that may be specialized by
/// this function specialization.
///
/// \param QualifiedFriend whether this is a lookup for a qualified friend
/// declaration with no explicit template argument list that might be
/// befriending a function template specialization.
bool Sema::CheckFunctionTemplateSpecialization(
FunctionDecl *FD, TemplateArgumentListInfo *ExplicitTemplateArgs,
LookupResult &Previous, bool QualifiedFriend) {
// The set of function template specializations that could match this
// explicit function template specialization.
UnresolvedSet<8> Candidates;
TemplateSpecCandidateSet FailedCandidates(FD->getLocation(),
/*ForTakingAddress=*/false);
llvm::SmallDenseMap<FunctionDecl *, TemplateArgumentListInfo, 8>
ConvertedTemplateArgs;
DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
I != E; ++I) {
NamedDecl *Ovl = (*I)->getUnderlyingDecl();
if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Ovl)) {
// Only consider templates found within the same semantic lookup scope as
// FD.
if (!FDLookupContext->InEnclosingNamespaceSetOf(
Ovl->getDeclContext()->getRedeclContext()))
continue;
// When matching a constexpr member function template specialization
// against the primary template, we don't yet know whether the
// specialization has an implicit 'const' (because we don't know whether
// it will be a static member function until we know which template it
// specializes), so adjust it now assuming it specializes this template.
QualType FT = FD->getType();
if (FD->isConstexpr()) {
CXXMethodDecl *OldMD =
dyn_cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl());
if (OldMD && OldMD->isConst()) {
const FunctionProtoType *FPT = FT->castAs<FunctionProtoType>();
FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
EPI.TypeQuals.addConst();
FT = Context.getFunctionType(FPT->getReturnType(),
FPT->getParamTypes(), EPI);
}
}
TemplateArgumentListInfo Args;
if (ExplicitTemplateArgs)
Args = *ExplicitTemplateArgs;
// C++ [temp.expl.spec]p11:
// A trailing template-argument can be left unspecified in the
// template-id naming an explicit function template specialization
// provided it can be deduced from the function argument type.
// Perform template argument deduction to determine whether we may be
// specializing this template.
// FIXME: It is somewhat wasteful to build
TemplateDeductionInfo Info(FailedCandidates.getLocation());
FunctionDecl *Specialization = nullptr;
if (TemplateDeductionResult TDK = DeduceTemplateArguments(
cast<FunctionTemplateDecl>(FunTmpl->getFirstDecl()),
ExplicitTemplateArgs ? &Args : nullptr, FT, Specialization,
Info)) {
// Template argument deduction failed; record why it failed, so
// that we can provide nifty diagnostics.
FailedCandidates.addCandidate().set(
I.getPair(), FunTmpl->getTemplatedDecl(),
MakeDeductionFailureInfo(Context, TDK, Info));
(void)TDK;
continue;
}
// Target attributes are part of the cuda function signature, so
// the deduced template's cuda target must match that of the
// specialization. Given that C++ template deduction does not
// take target attributes into account, we reject candidates
// here that have a different target.
if (LangOpts.CUDA &&
IdentifyCUDATarget(Specialization,
/* IgnoreImplicitHDAttr = */ true) !=
IdentifyCUDATarget(FD, /* IgnoreImplicitHDAttr = */ true)) {
FailedCandidates.addCandidate().set(
I.getPair(), FunTmpl->getTemplatedDecl(),
MakeDeductionFailureInfo(Context, TDK_CUDATargetMismatch, Info));
continue;
}
// Record this candidate.
if (ExplicitTemplateArgs)
ConvertedTemplateArgs[Specialization] = std::move(Args);
Candidates.addDecl(Specialization, I.getAccess());
}
}
// For a qualified friend declaration (with no explicit marker to indicate
// that a template specialization was intended), note all (template and
// non-template) candidates.
if (QualifiedFriend && Candidates.empty()) {
Diag(FD->getLocation(), diag::err_qualified_friend_no_match)
<< FD->getDeclName() << FDLookupContext;
// FIXME: We should form a single candidate list and diagnose all
// candidates at once, to get proper sorting and limiting.
for (auto *OldND : Previous) {
if (auto *OldFD = dyn_cast<FunctionDecl>(OldND->getUnderlyingDecl()))
NoteOverloadCandidate(OldND, OldFD, CRK_None, FD->getType(), false);
}
FailedCandidates.NoteCandidates(*this, FD->getLocation());
return true;
}
// Find the most specialized function template.
UnresolvedSetIterator Result = getMostSpecialized(
Candidates.begin(), Candidates.end(), FailedCandidates, FD->getLocation(),
PDiag(diag::err_function_template_spec_no_match) << FD->getDeclName(),
PDiag(diag::err_function_template_spec_ambiguous)
<< FD->getDeclName() << (ExplicitTemplateArgs != nullptr),
PDiag(diag::note_function_template_spec_matched));
if (Result == Candidates.end())
return true;
// Ignore access information; it doesn't figure into redeclaration checking.
FunctionDecl *Specialization = cast<FunctionDecl>(*Result);
FunctionTemplateSpecializationInfo *SpecInfo
= Specialization->getTemplateSpecializationInfo();
assert(SpecInfo && "Function template specialization info missing?");
// Note: do not overwrite location info if previous template
// specialization kind was explicit.
TemplateSpecializationKind TSK = SpecInfo->getTemplateSpecializationKind();
if (TSK == TSK_Undeclared || TSK == TSK_ImplicitInstantiation) {
Specialization->setLocation(FD->getLocation());
Specialization->setLexicalDeclContext(FD->getLexicalDeclContext());
// C++11 [dcl.constexpr]p1: An explicit specialization of a constexpr
// function can differ from the template declaration with respect to
// the constexpr specifier.
// FIXME: We need an update record for this AST mutation.
// FIXME: What if there are multiple such prior declarations (for instance,
// from different modules)?
Specialization->setConstexprKind(FD->getConstexprKind());
}
// FIXME: Check if the prior specialization has a point of instantiation.
// If so, we have run afoul of .
// If this is a friend declaration, then we're not really declaring
// an explicit specialization.
bool isFriend = (FD->getFriendObjectKind() != Decl::FOK_None);
// Check the scope of this explicit specialization.
if (!isFriend &&
CheckTemplateSpecializationScope(*this,
Specialization->getPrimaryTemplate(),
Specialization, FD->getLocation(),
false))
return true;
// C++ [temp.expl.spec]p6:
// If a template, a member template or the member of a class template is
// explicitly specialized then that specialization shall be declared
// before the first use of that specialization that would cause an implicit
// instantiation to take place, in every translation unit in which such a
// use occurs; no diagnostic is required.
bool HasNoEffect = false;
if (!isFriend &&
CheckSpecializationInstantiationRedecl(FD->getLocation(),
TSK_ExplicitSpecialization,
Specialization,
SpecInfo->getTemplateSpecializationKind(),
SpecInfo->getPointOfInstantiation(),
HasNoEffect))
return true;
// Mark the prior declaration as an explicit specialization, so that later
// clients know that this is an explicit specialization.
if (!isFriend) {
// Since explicit specializations do not inherit '=delete' from their
// primary function template - check if the 'specialization' that was
// implicitly generated (during template argument deduction for partial
// ordering) from the most specialized of all the function templates that
// 'FD' could have been specializing, has a 'deleted' definition. If so,
// first check that it was implicitly generated during template argument
// deduction by making sure it wasn't referenced, and then reset the deleted
// flag to not-deleted, so that we can inherit that information from 'FD'.
if (Specialization->isDeleted() && !SpecInfo->isExplicitSpecialization() &&
!Specialization->getCanonicalDecl()->isReferenced()) {
// FIXME: This assert will not hold in the presence of modules.
assert(
Specialization->getCanonicalDecl() == Specialization &&
"This must be the only existing declaration of this specialization");
// FIXME: We need an update record for this AST mutation.
Specialization->setDeletedAsWritten(false);
}
// FIXME: We need an update record for this AST mutation.
SpecInfo->setTemplateSpecializationKind(TSK_ExplicitSpecialization);
MarkUnusedFileScopedDecl(Specialization);
}
// Turn the given function declaration into a function template
// specialization, with the template arguments from the previous
// specialization.
// Take copies of (semantic and syntactic) template argument lists.
const TemplateArgumentList* TemplArgs = new (Context)
TemplateArgumentList(Specialization->getTemplateSpecializationArgs());
FD->setFunctionTemplateSpecialization(
Specialization->getPrimaryTemplate(), TemplArgs, /*InsertPos=*/nullptr,
SpecInfo->getTemplateSpecializationKind(),
ExplicitTemplateArgs ? &ConvertedTemplateArgs[Specialization] : nullptr);
// A function template specialization inherits the target attributes
// of its template. (We require the attributes explicitly in the
// code to match, but a template may have implicit attributes by
// virtue e.g. of being constexpr, and it passes these implicit
// attributes on to its specializations.)
if (LangOpts.CUDA)
inheritCUDATargetAttrs(FD, *Specialization->getPrimaryTemplate());
// The "previous declaration" for this function template specialization is
// the prior function template specialization.
Previous.clear();
Previous.addDecl(Specialization);
return false;
}
/// Perform semantic analysis for the given non-template member
/// specialization.
///
/// This routine performs all of the semantic analysis required for an
/// explicit member function specialization. On successful completion,
/// the function declaration \p FD will become a member function
/// specialization.
///
/// \param Member the member declaration, which will be updated to become a
/// specialization.
///
/// \param Previous the set of declarations, one of which may be specialized
/// by this function specialization; the set will be modified to contain the
/// redeclared member.
bool
Sema::CheckMemberSpecialization(NamedDecl *Member, LookupResult &Previous) {
assert(!isa<TemplateDecl>(Member) && "Only for non-template members");
// Try to find the member we are instantiating.
NamedDecl *FoundInstantiation = nullptr;
NamedDecl *Instantiation = nullptr;
NamedDecl *InstantiatedFrom = nullptr;
MemberSpecializationInfo *MSInfo = nullptr;
if (Previous.empty()) {
// Nowhere to look anyway.
} else if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Member)) {
for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
I != E; ++I) {
NamedDecl *D = (*I)->getUnderlyingDecl();
if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
QualType Adjusted = Function->getType();
if (!hasExplicitCallingConv(Adjusted))
Adjusted = adjustCCAndNoReturn(Adjusted, Method->getType());
// This doesn't handle deduced return types, but both function
// declarations should be undeduced at this point.
if (Context.hasSameType(Adjusted, Method->getType())) {
FoundInstantiation = *I;
Instantiation = Method;
InstantiatedFrom = Method->getInstantiatedFromMemberFunction();
MSInfo = Method->getMemberSpecializationInfo();
break;
}
}
}
} else if (isa<VarDecl>(Member)) {
VarDecl *PrevVar;
if (Previous.isSingleResult() &&
(PrevVar = dyn_cast<VarDecl>(Previous.getFoundDecl())))
if (PrevVar->isStaticDataMember()) {
FoundInstantiation = Previous.getRepresentativeDecl();
Instantiation = PrevVar;
InstantiatedFrom = PrevVar->getInstantiatedFromStaticDataMember();
MSInfo = PrevVar->getMemberSpecializationInfo();
}
} else if (isa<RecordDecl>(Member)) {
CXXRecordDecl *PrevRecord;
if (Previous.isSingleResult() &&
(PrevRecord = dyn_cast<CXXRecordDecl>(Previous.getFoundDecl()))) {
FoundInstantiation = Previous.getRepresentativeDecl();
Instantiation = PrevRecord;
InstantiatedFrom = PrevRecord->getInstantiatedFromMemberClass();
MSInfo = PrevRecord->getMemberSpecializationInfo();
}
} else if (isa<EnumDecl>(Member)) {
EnumDecl *PrevEnum;
if (Previous.isSingleResult() &&
(PrevEnum = dyn_cast<EnumDecl>(Previous.getFoundDecl()))) {
FoundInstantiation = Previous.getRepresentativeDecl();
Instantiation = PrevEnum;
InstantiatedFrom = PrevEnum->getInstantiatedFromMemberEnum();
MSInfo = PrevEnum->getMemberSpecializationInfo();
}
}
if (!Instantiation) {
// There is no previous declaration that matches. Since member
// specializations are always out-of-line, the caller will complain about
// this mismatch later.
return false;
}
// A member specialization in a friend declaration isn't really declaring
// an explicit specialization, just identifying a specific (possibly implicit)
// specialization. Don't change the template specialization kind.
//
// FIXME: Is this really valid? Other compilers reject.
if (Member->getFriendObjectKind() != Decl::FOK_None) {
// Preserve instantiation information.
if (InstantiatedFrom && isa<CXXMethodDecl>(Member)) {
cast<CXXMethodDecl>(Member)->setInstantiationOfMemberFunction(
cast<CXXMethodDecl>(InstantiatedFrom),
cast<CXXMethodDecl>(Instantiation)->getTemplateSpecializationKind());
} else if (InstantiatedFrom && isa<CXXRecordDecl>(Member)) {
cast<CXXRecordDecl>(Member)->setInstantiationOfMemberClass(
cast<CXXRecordDecl>(InstantiatedFrom),
cast<CXXRecordDecl>(Instantiation)->getTemplateSpecializationKind());
}
Previous.clear();
Previous.addDecl(FoundInstantiation);
return false;
}
// Make sure that this is a specialization of a member.
if (!InstantiatedFrom) {
Diag(Member->getLocation(), diag::err_spec_member_not_instantiated)
<< Member;
Diag(Instantiation->getLocation(), diag::note_specialized_decl);
return true;
}
// C++ [temp.expl.spec]p6:
// If a template, a member template or the member of a class template is
// explicitly specialized then that specialization shall be declared
// before the first use of that specialization that would cause an implicit
// instantiation to take place, in every translation unit in which such a
// use occurs; no diagnostic is required.
assert(MSInfo && "Member specialization info missing?");
bool HasNoEffect = false;
if (CheckSpecializationInstantiationRedecl(Member->getLocation(),
TSK_ExplicitSpecialization,
Instantiation,
MSInfo->getTemplateSpecializationKind(),
MSInfo->getPointOfInstantiation(),
HasNoEffect))
return true;
// Check the scope of this explicit specialization.
if (CheckTemplateSpecializationScope(*this,
InstantiatedFrom,
Instantiation, Member->getLocation(),
false))
return true;
// Note that this member specialization is an "instantiation of" the
// corresponding member of the original template.
if (auto *MemberFunction = dyn_cast<FunctionDecl>(Member)) {
FunctionDecl *InstantiationFunction = cast<FunctionDecl>(Instantiation);
if (InstantiationFunction->getTemplateSpecializationKind() ==
TSK_ImplicitInstantiation) {
// Explicit specializations of member functions of class templates do not
// inherit '=delete' from the member function they are specializing.
if (InstantiationFunction->isDeleted()) {
// FIXME: This assert will not hold in the presence of modules.
assert(InstantiationFunction->getCanonicalDecl() ==
InstantiationFunction);
// FIXME: We need an update record for this AST mutation.
InstantiationFunction->setDeletedAsWritten(false);
}
}
MemberFunction->setInstantiationOfMemberFunction(
cast<CXXMethodDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
} else if (auto *MemberVar = dyn_cast<VarDecl>(Member)) {
MemberVar->setInstantiationOfStaticDataMember(
cast<VarDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
} else if (auto *MemberClass = dyn_cast<CXXRecordDecl>(Member)) {
MemberClass->setInstantiationOfMemberClass(
cast<CXXRecordDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
} else if (auto *MemberEnum = dyn_cast<EnumDecl>(Member)) {
MemberEnum->setInstantiationOfMemberEnum(
cast<EnumDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
} else {
llvm_unreachable("unknown member specialization kind");
}
// Save the caller the trouble of having to figure out which declaration
// this specialization matches.
Previous.clear();
Previous.addDecl(FoundInstantiation);
return false;
}
/// Complete the explicit specialization of a member of a class template by
/// updating the instantiated member to be marked as an explicit specialization.
///
/// \param OrigD The member declaration instantiated from the template.
/// \param Loc The location of the explicit specialization of the member.
template<typename DeclT>
static void completeMemberSpecializationImpl(Sema &S, DeclT *OrigD,
SourceLocation Loc) {
if (OrigD->getTemplateSpecializationKind() != TSK_ImplicitInstantiation)
return;
// FIXME: Inform AST mutation listeners of this AST mutation.
// FIXME: If there are multiple in-class declarations of the member (from
// multiple modules, or a declaration and later definition of a member type),
// should we update all of them?
OrigD->setTemplateSpecializationKind(TSK_ExplicitSpecialization);
OrigD->setLocation(Loc);
}
void Sema::CompleteMemberSpecialization(NamedDecl *Member,
LookupResult &Previous) {
NamedDecl *Instantiation = cast<NamedDecl>(Member->getCanonicalDecl());
if (Instantiation == Member)
return;
if (auto *Function = dyn_cast<CXXMethodDecl>(Instantiation))
completeMemberSpecializationImpl(*this, Function, Member->getLocation());
else if (auto *Var = dyn_cast<VarDecl>(Instantiation))
completeMemberSpecializationImpl(*this, Var, Member->getLocation());
else if (auto *Record = dyn_cast<CXXRecordDecl>(Instantiation))
completeMemberSpecializationImpl(*this, Record, Member->getLocation());
else if (auto *Enum = dyn_cast<EnumDecl>(Instantiation))
completeMemberSpecializationImpl(*this, Enum, Member->getLocation());
else
llvm_unreachable("unknown member specialization kind");
}
/// Check the scope of an explicit instantiation.
///
/// \returns true if a serious error occurs, false otherwise.
static bool CheckExplicitInstantiationScope(Sema &S, NamedDecl *D,
SourceLocation InstLoc,
bool WasQualifiedName) {
DeclContext *OrigContext= D->getDeclContext()->getEnclosingNamespaceContext();
DeclContext *CurContext = S.CurContext->getRedeclContext();
if (CurContext->isRecord()) {
S.Diag(InstLoc, diag::err_explicit_instantiation_in_class)
<< D;
return true;
}
// C++11 [temp.explicit]p3:
// An explicit instantiation shall appear in an enclosing namespace of its
// template. If the name declared in the explicit instantiation is an
// unqualified name, the explicit instantiation shall appear in the
// namespace where its template is declared or, if that namespace is inline
// (7.3.1), any namespace from its enclosing namespace set.
//
// This is DR275, which we do not retroactively apply to C++98/03.
if (WasQualifiedName) {
if (CurContext->Encloses(OrigContext))
return false;
} else {
if (CurContext->InEnclosingNamespaceSetOf(OrigContext))
return false;
}
if (NamespaceDecl *NS = dyn_cast<NamespaceDecl>(OrigContext)) {
if (WasQualifiedName)
S.Diag(InstLoc,
S.getLangOpts().CPlusPlus11?
diag::err_explicit_instantiation_out_of_scope :
diag::warn_explicit_instantiation_out_of_scope_0x)
<< D << NS;
else
S.Diag(InstLoc,
S.getLangOpts().CPlusPlus11?
diag::err_explicit_instantiation_unqualified_wrong_namespace :
diag::warn_explicit_instantiation_unqualified_wrong_namespace_0x)
<< D << NS;
} else
S.Diag(InstLoc,
S.getLangOpts().CPlusPlus11?
diag::err_explicit_instantiation_must_be_global :
diag::warn_explicit_instantiation_must_be_global_0x)
<< D;
S.Diag(D->getLocation(), diag::note_explicit_instantiation_here);
return false;
}
/// Common checks for whether an explicit instantiation of \p D is valid.
static bool CheckExplicitInstantiation(Sema &S, NamedDecl *D,
SourceLocation InstLoc,
bool WasQualifiedName,
TemplateSpecializationKind TSK) {
// C++ [temp.explicit]p13:
// An explicit instantiation declaration shall not name a specialization of
// a template with internal linkage.
if (TSK == TSK_ExplicitInstantiationDeclaration &&
D->getFormalLinkage() == InternalLinkage) {
S.Diag(InstLoc, diag::err_explicit_instantiation_internal_linkage) << D;
return true;
}
// C++11 [temp.explicit]p3: [DR 275]
// An explicit instantiation shall appear in an enclosing namespace of its
// template.
if (CheckExplicitInstantiationScope(S, D, InstLoc, WasQualifiedName))
return true;
return false;
}
/// Determine whether the given scope specifier has a template-id in it.
static bool ScopeSpecifierHasTemplateId(const CXXScopeSpec &SS) {
if (!SS.isSet())
return false;
// C++11 [temp.explicit]p3:
// If the explicit instantiation is for a member function, a member class
// or a static data member of a class template specialization, the name of
// the class template specialization in the qualified-id for the member
// name shall be a simple-template-id.
//
// C++98 has the same restriction, just worded differently.
for (NestedNameSpecifier *NNS = SS.getScopeRep(); NNS;
NNS = NNS->getPrefix())
if (const Type *T = NNS->getAsType())
if (isa<TemplateSpecializationType>(T))
return true;
return false;
}
/// Make a dllexport or dllimport attr on a class template specialization take
/// effect.
static void dllExportImportClassTemplateSpecialization(
Sema &S, ClassTemplateSpecializationDecl *Def) {
auto *A = cast_or_null<InheritableAttr>(getDLLAttr(Def));
assert(A && "dllExportImportClassTemplateSpecialization called "
"on Def without dllexport or dllimport");
// We reject explicit instantiations in class scope, so there should
// never be any delayed exported classes to worry about.
assert(S.DelayedDllExportClasses.empty() &&
"delayed exports present at explicit instantiation");
S.checkClassLevelDLLAttribute(Def);
// Propagate attribute to base class templates.
for (auto &B : Def->bases()) {
if (auto *BT = dyn_cast_or_null<ClassTemplateSpecializationDecl>(
B.getType()->getAsCXXRecordDecl()))
S.propagateDLLAttrToBaseClassTemplate(Def, A, BT, B.getBeginLoc());
}
S.referenceDLLExportedClassMethods();
}
// Explicit instantiation of a class template specialization
DeclResult Sema::ActOnExplicitInstantiation(
Scope *S, SourceLocation ExternLoc, SourceLocation TemplateLoc,
unsigned TagSpec, SourceLocation KWLoc, const CXXScopeSpec &SS,
TemplateTy TemplateD, SourceLocation TemplateNameLoc,
SourceLocation LAngleLoc, ASTTemplateArgsPtr TemplateArgsIn,
SourceLocation RAngleLoc, const ParsedAttributesView &Attr) {
// Find the class template we're specializing
TemplateName Name = TemplateD.get();
TemplateDecl *TD = Name.getAsTemplateDecl();
// Check that the specialization uses the same tag kind as the
// original template.
TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
assert(Kind != TTK_Enum &&
"Invalid enum tag in class template explicit instantiation!");
ClassTemplateDecl *ClassTemplate = dyn_cast<ClassTemplateDecl>(TD);
if (!ClassTemplate) {
NonTagKind NTK = getNonTagTypeDeclKind(TD, Kind);
Diag(TemplateNameLoc, diag::err_tag_reference_non_tag) << TD << NTK << Kind;
Diag(TD->getLocation(), diag::note_previous_use);
return true;
}
if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
Kind, /*isDefinition*/false, KWLoc,
ClassTemplate->getIdentifier())) {
Diag(KWLoc, diag::err_use_with_wrong_tag)
<< ClassTemplate
<< FixItHint::CreateReplacement(KWLoc,
ClassTemplate->getTemplatedDecl()->getKindName());
Diag(ClassTemplate->getTemplatedDecl()->getLocation(),
diag::note_previous_use);
Kind = ClassTemplate->getTemplatedDecl()->getTagKind();
}
// C++0x [temp.explicit]p2:
// There are two forms of explicit instantiation: an explicit instantiation
// definition and an explicit instantiation declaration. An explicit
// instantiation declaration begins with the extern keyword. [...]
TemplateSpecializationKind TSK = ExternLoc.isInvalid()
? TSK_ExplicitInstantiationDefinition
: TSK_ExplicitInstantiationDeclaration;
if (TSK == TSK_ExplicitInstantiationDeclaration &&
!Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
// Check for dllexport class template instantiation declarations,
// except for MinGW mode.
for (const ParsedAttr &AL : Attr) {
if (AL.getKind() == ParsedAttr::AT_DLLExport) {
Diag(ExternLoc,
diag::warn_attribute_dllexport_explicit_instantiation_decl);
Diag(AL.getLoc(), diag::note_attribute);
break;
}
}
if (auto *A = ClassTemplate->getTemplatedDecl()->getAttr<DLLExportAttr>()) {
Diag(ExternLoc,
diag::warn_attribute_dllexport_explicit_instantiation_decl);
Diag(A->getLocation(), diag::note_attribute);
}
}
// In MSVC mode, dllimported explicit instantiation definitions are treated as
// instantiation declarations for most purposes.
bool DLLImportExplicitInstantiationDef = false;
if (TSK == TSK_ExplicitInstantiationDefinition &&
Context.getTargetInfo().getCXXABI().isMicrosoft()) {
// Check for dllimport class template instantiation definitions.
bool DLLImport =
ClassTemplate->getTemplatedDecl()->getAttr<DLLImportAttr>();
for (const ParsedAttr &AL : Attr) {
if (AL.getKind() == ParsedAttr::AT_DLLImport)
DLLImport = true;
if (AL.getKind() == ParsedAttr::AT_DLLExport) {
// dllexport trumps dllimport here.
DLLImport = false;
break;
}
}
if (DLLImport) {
TSK = TSK_ExplicitInstantiationDeclaration;
DLLImportExplicitInstantiationDef = true;
}
}
// Translate the parser's template argument list in our AST format.
TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
translateTemplateArguments(TemplateArgsIn, TemplateArgs);
// Check that the template argument list is well-formed for this
// template.
SmallVector<TemplateArgument, 4> Converted;
if (CheckTemplateArgumentList(ClassTemplate, TemplateNameLoc,
TemplateArgs, false, Converted,
/*UpdateArgsWithConversions=*/true))
return true;
// Find the class template specialization declaration that
// corresponds to these arguments.
void *InsertPos = nullptr;
ClassTemplateSpecializationDecl *PrevDecl
= ClassTemplate->findSpecialization(Converted, InsertPos);
TemplateSpecializationKind PrevDecl_TSK
= PrevDecl ? PrevDecl->getTemplateSpecializationKind() : TSK_Undeclared;
if (TSK == TSK_ExplicitInstantiationDefinition && PrevDecl != nullptr &&
Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
// Check for dllexport class template instantiation definitions in MinGW
// mode, if a previous declaration of the instantiation was seen.
for (const ParsedAttr &AL : Attr) {
if (AL.getKind() == ParsedAttr::AT_DLLExport) {
Diag(AL.getLoc(),
diag::warn_attribute_dllexport_explicit_instantiation_def);
break;
}
}
}
if (CheckExplicitInstantiation(*this, ClassTemplate, TemplateNameLoc,
SS.isSet(), TSK))
return true;
ClassTemplateSpecializationDecl *Specialization = nullptr;
bool HasNoEffect = false;
if (PrevDecl) {
if (CheckSpecializationInstantiationRedecl(TemplateNameLoc, TSK,
PrevDecl, PrevDecl_TSK,
PrevDecl->getPointOfInstantiation(),
HasNoEffect))
return PrevDecl;
// Even though HasNoEffect == true means that this explicit instantiation
// has no effect on semantics, we go on to put its syntax in the AST.
if (PrevDecl_TSK == TSK_ImplicitInstantiation ||
PrevDecl_TSK == TSK_Undeclared) {
// Since the only prior class template specialization with these
// arguments was referenced but not declared, reuse that
// declaration node as our own, updating the source location
// for the template name to reflect our new declaration.
// (Other source locations will be updated later.)
Specialization = PrevDecl;
Specialization->setLocation(TemplateNameLoc);
PrevDecl = nullptr;
}
if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
DLLImportExplicitInstantiationDef) {
// The new specialization might add a dllimport attribute.
HasNoEffect = false;
}
}
if (!Specialization) {
// Create a new class template specialization declaration node for
// this explicit specialization.
Specialization
= ClassTemplateSpecializationDecl::Create(Context, Kind,
ClassTemplate->getDeclContext(),
KWLoc, TemplateNameLoc,
ClassTemplate,
Converted,
PrevDecl);
SetNestedNameSpecifier(*this, Specialization, SS);
if (!HasNoEffect && !PrevDecl) {
// Insert the new specialization.
ClassTemplate->AddSpecialization(Specialization, InsertPos);
}
}
// Build the fully-sugared type for this explicit instantiation as
// the user wrote in the explicit instantiation itself. This means
// that we'll pretty-print the type retrieved from the
// specialization's declaration the way that the user actually wrote
// the explicit instantiation, rather than formatting the name based
// on the "canonical" representation used to store the template
// arguments in the specialization.
TypeSourceInfo *WrittenTy
= Context.getTemplateSpecializationTypeInfo(Name, TemplateNameLoc,
TemplateArgs,
Context.getTypeDeclType(Specialization));
Specialization->setTypeAsWritten(WrittenTy);
// Set source locations for keywords.
Specialization->setExternLoc(ExternLoc);
Specialization->setTemplateKeywordLoc(TemplateLoc);
Specialization->setBraceRange(SourceRange());
bool PreviouslyDLLExported = Specialization->hasAttr<DLLExportAttr>();
ProcessDeclAttributeList(S, Specialization, Attr);
// Add the explicit instantiation into its lexical context. However,
// since explicit instantiations are never found by name lookup, we
// just put it into the declaration context directly.
Specialization->setLexicalDeclContext(CurContext);
CurContext->addDecl(Specialization);
// Syntax is now OK, so return if it has no other effect on semantics.
if (HasNoEffect) {
// Set the template specialization kind.
Specialization->setTemplateSpecializationKind(TSK);
return Specialization;
}
// C++ [temp.explicit]p3:
// A definition of a class template or class member template
// shall be in scope at the point of the explicit instantiation of
// the class template or class member template.
//
// This check comes when we actually try to perform the
// instantiation.
ClassTemplateSpecializationDecl *Def
= cast_or_null<ClassTemplateSpecializationDecl>(
Specialization->getDefinition());
if (!Def)
InstantiateClassTemplateSpecialization(TemplateNameLoc, Specialization, TSK);
else if (TSK == TSK_ExplicitInstantiationDefinition) {
MarkVTableUsed(TemplateNameLoc, Specialization, true);
Specialization->setPointOfInstantiation(Def->getPointOfInstantiation());
}
// Instantiate the members of this class template specialization.
Def = cast_or_null<ClassTemplateSpecializationDecl>(
Specialization->getDefinition());
if (Def) {
TemplateSpecializationKind Old_TSK = Def->getTemplateSpecializationKind();
// Fix a TSK_ExplicitInstantiationDeclaration followed by a
// TSK_ExplicitInstantiationDefinition
if (Old_TSK == TSK_ExplicitInstantiationDeclaration &&
(TSK == TSK_ExplicitInstantiationDefinition ||
DLLImportExplicitInstantiationDef)) {
// FIXME: Need to notify the ASTMutationListener that we did this.
Def->setTemplateSpecializationKind(TSK);
if (!getDLLAttr(Def) && getDLLAttr(Specialization) &&
(Context.getTargetInfo().shouldDLLImportComdatSymbols() &&
!Context.getTargetInfo().getTriple().isPS4())) {
// An explicit instantiation definition can add a dll attribute to a
// template with a previous instantiation declaration. MinGW doesn't
// allow this.
auto *A = cast<InheritableAttr>(
getDLLAttr(Specialization)->clone(getASTContext()));
A->setInherited(true);
Def->addAttr(A);
dllExportImportClassTemplateSpecialization(*this, Def);
}
}
// Fix a TSK_ImplicitInstantiation followed by a
// TSK_ExplicitInstantiationDefinition
bool NewlyDLLExported =
!PreviouslyDLLExported && Specialization->hasAttr<DLLExportAttr>();
if (Old_TSK == TSK_ImplicitInstantiation && NewlyDLLExported &&
(Context.getTargetInfo().shouldDLLImportComdatSymbols() &&
!Context.getTargetInfo().getTriple().isPS4())) {
// An explicit instantiation definition can add a dll attribute to a
// template with a previous implicit instantiation. MinGW doesn't allow
// this. We limit clang to only adding dllexport, to avoid potentially
// strange codegen behavior. For example, if we extend this conditional
// to dllimport, and we have a source file calling a method on an
// implicitly instantiated template class instance and then declaring a
// dllimport explicit instantiation definition for the same template
// class, the codegen for the method call will not respect the dllimport,
// while it will with cl. The Def will already have the DLL attribute,
// since the Def and Specialization will be the same in the case of
// Old_TSK == TSK_ImplicitInstantiation, and we already added the
// attribute to the Specialization; we just need to make it take effect.
assert(Def == Specialization &&
"Def and Specialization should match for implicit instantiation");
dllExportImportClassTemplateSpecialization(*this, Def);
}
// In MinGW mode, export the template instantiation if the declaration
// was marked dllexport.
if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
Context.getTargetInfo().getTriple().isWindowsGNUEnvironment() &&
PrevDecl->hasAttr<DLLExportAttr>()) {
dllExportImportClassTemplateSpecialization(*this, Def);
}
if (Def->hasAttr<MSInheritanceAttr>()) {
Specialization->addAttr(Def->getAttr<MSInheritanceAttr>());
Consumer.AssignInheritanceModel(Specialization);
}
// Set the template specialization kind. Make sure it is set before
// instantiating the members which will trigger ASTConsumer callbacks.
Specialization->setTemplateSpecializationKind(TSK);
InstantiateClassTemplateSpecializationMembers(TemplateNameLoc, Def, TSK);
} else {
// Set the template specialization kind.
Specialization->setTemplateSpecializationKind(TSK);
}
return Specialization;
}
// Explicit instantiation of a member class of a class template.
DeclResult
Sema::ActOnExplicitInstantiation(Scope *S, SourceLocation ExternLoc,
SourceLocation TemplateLoc, unsigned TagSpec,
SourceLocation KWLoc, CXXScopeSpec &SS,
IdentifierInfo *Name, SourceLocation NameLoc,
const ParsedAttributesView &Attr) {
bool Owned = false;
bool IsDependent = false;
Decl *TagD = ActOnTag(S, TagSpec, Sema::TUK_Reference,
KWLoc, SS, Name, NameLoc, Attr, AS_none,
/*ModulePrivateLoc=*/SourceLocation(),
MultiTemplateParamsArg(), Owned, IsDependent,
SourceLocation(), false, TypeResult(),
/*IsTypeSpecifier*/false,
/*IsTemplateParamOrArg*/false);
assert(!IsDependent && "explicit instantiation of dependent name not yet handled");
if (!TagD)
return true;
TagDecl *Tag = cast<TagDecl>(TagD);
assert(!Tag->isEnum() && "shouldn't see enumerations here");
if (Tag->isInvalidDecl())
return true;
CXXRecordDecl *Record = cast<CXXRecordDecl>(Tag);
CXXRecordDecl *Pattern = Record->getInstantiatedFromMemberClass();
if (!Pattern) {
Diag(TemplateLoc, diag::err_explicit_instantiation_nontemplate_type)
<< Context.getTypeDeclType(Record);
Diag(Record->getLocation(), diag::note_nontemplate_decl_here);
return true;
}
// C++0x [temp.explicit]p2:
// If the explicit instantiation is for a class or member class, the
// elaborated-type-specifier in the declaration shall include a
// simple-template-id.
//
// C++98 has the same restriction, just worded differently.
if (!ScopeSpecifierHasTemplateId(SS))
Diag(TemplateLoc, diag::ext_explicit_instantiation_without_qualified_id)
<< Record << SS.getRange();
// C++0x [temp.explicit]p2:
// There are two forms of explicit instantiation: an explicit instantiation
// definition and an explicit instantiation declaration. An explicit
// instantiation declaration begins with the extern keyword. [...]
TemplateSpecializationKind TSK
= ExternLoc.isInvalid()? TSK_ExplicitInstantiationDefinition
: TSK_ExplicitInstantiationDeclaration;
CheckExplicitInstantiation(*this, Record, NameLoc, true, TSK);
// Verify that it is okay to explicitly instantiate here.
CXXRecordDecl *PrevDecl
= cast_or_null<CXXRecordDecl>(Record->getPreviousDecl());
if (!PrevDecl && Record->getDefinition())
PrevDecl = Record;
if (PrevDecl) {
MemberSpecializationInfo *MSInfo = PrevDecl->getMemberSpecializationInfo();
bool HasNoEffect = false;
assert(MSInfo && "No member specialization information?");
if (CheckSpecializationInstantiationRedecl(TemplateLoc, TSK,
PrevDecl,
MSInfo->getTemplateSpecializationKind(),
MSInfo->getPointOfInstantiation(),
HasNoEffect))
return true;
if (HasNoEffect)
return TagD;
}
CXXRecordDecl *RecordDef
= cast_or_null<CXXRecordDecl>(Record->getDefinition());
if (!RecordDef) {
// C++ [temp.explicit]p3:
// A definition of a member class of a class template shall be in scope
// at the point of an explicit instantiation of the member class.
CXXRecordDecl *Def
= cast_or_null<CXXRecordDecl>(Pattern->getDefinition());
if (!Def) {
Diag(TemplateLoc, diag::err_explicit_instantiation_undefined_member)
<< 0 << Record->getDeclName() << Record->getDeclContext();
Diag(Pattern->getLocation(), diag::note_forward_declaration)
<< Pattern;
return true;
} else {
if (InstantiateClass(NameLoc, Record, Def,
getTemplateInstantiationArgs(Record),
TSK))
return true;
RecordDef = cast_or_null<CXXRecordDecl>(Record->getDefinition());
if (!RecordDef)
return true;
}
}
// Instantiate all of the members of the class.
InstantiateClassMembers(NameLoc, RecordDef,
getTemplateInstantiationArgs(Record), TSK);
if (TSK == TSK_ExplicitInstantiationDefinition)
MarkVTableUsed(NameLoc, RecordDef, true);
// FIXME: We don't have any representation for explicit instantiations of
// member classes. Such a representation is not needed for compilation, but it
// should be available for clients that want to see all of the declarations in
// the source code.
return TagD;
}
DeclResult Sema::ActOnExplicitInstantiation(Scope *S,
SourceLocation ExternLoc,
SourceLocation TemplateLoc,
Declarator &D) {
// Explicit instantiations always require a name.
// TODO: check if/when DNInfo should replace Name.
DeclarationNameInfo NameInfo = GetNameForDeclarator(D);
DeclarationName Name = NameInfo.getName();
if (!Name) {
if (!D.isInvalidType())
Diag(D.getDeclSpec().getBeginLoc(),
diag::err_explicit_instantiation_requires_name)
<< D.getDeclSpec().getSourceRange() << D.getSourceRange();
return true;
}
// The scope passed in may not be a decl scope. Zip up the scope tree until
// we find one that is.
while ((S->getFlags() & Scope::DeclScope) == 0 ||
(S->getFlags() & Scope::TemplateParamScope) != 0)
S = S->getParent();
// Determine the type of the declaration.
TypeSourceInfo *T = GetTypeForDeclarator(D, S);
QualType R = T->getType();
if (R.isNull())
return true;
// C++ [dcl.stc]p1:
// A storage-class-specifier shall not be specified in [...] an explicit
// instantiation (14.7.2) directive.
if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_typedef) {
Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_of_typedef)
<< Name;
return true;
} else if (D.getDeclSpec().getStorageClassSpec()
!= DeclSpec::SCS_unspecified) {
// Complain about then remove the storage class specifier.
Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_storage_class)
<< FixItHint::CreateRemoval(D.getDeclSpec().getStorageClassSpecLoc());
D.getMutableDeclSpec().ClearStorageClassSpecs();
}
// C++0x [temp.explicit]p1:
// [...] An explicit instantiation of a function template shall not use the
// inline or constexpr specifiers.
// Presumably, this also applies to member functions of class templates as
// well.
if (D.getDeclSpec().isInlineSpecified())
Diag(D.getDeclSpec().getInlineSpecLoc(),
getLangOpts().CPlusPlus11 ?
diag::err_explicit_instantiation_inline :
diag::warn_explicit_instantiation_inline_0x)
<< FixItHint::CreateRemoval(D.getDeclSpec().getInlineSpecLoc());
if (D.getDeclSpec().hasConstexprSpecifier() && R->isFunctionType())
// FIXME: Add a fix-it to remove the 'constexpr' and add a 'const' if one is
// not already specified.
Diag(D.getDeclSpec().getConstexprSpecLoc(),
diag::err_explicit_instantiation_constexpr);
// A deduction guide is not on the list of entities that can be explicitly
// instantiated.
if (Name.getNameKind() == DeclarationName::CXXDeductionGuideName) {
Diag(D.getDeclSpec().getBeginLoc(), diag::err_deduction_guide_specialized)
<< /*explicit instantiation*/ 0;
return true;
}
// C++0x [temp.explicit]p2:
// There are two forms of explicit instantiation: an explicit instantiation
// definition and an explicit instantiation declaration. An explicit
// instantiation declaration begins with the extern keyword. [...]
TemplateSpecializationKind TSK
= ExternLoc.isInvalid()? TSK_ExplicitInstantiationDefinition
: TSK_ExplicitInstantiationDeclaration;
LookupResult Previous(*this, NameInfo, LookupOrdinaryName);
LookupParsedName(Previous, S, &D.getCXXScopeSpec());
if (!R->isFunctionType()) {
// C++ [temp.explicit]p1:
// A [...] static data member of a class template can be explicitly
// instantiated from the member definition associated with its class
// template.
// C++1y [temp.explicit]p1:
// A [...] variable [...] template specialization can be explicitly
// instantiated from its template.
if (Previous.isAmbiguous())
return true;
VarDecl *Prev = Previous.getAsSingle<VarDecl>();
VarTemplateDecl *PrevTemplate = Previous.getAsSingle<VarTemplateDecl>();
if (!PrevTemplate) {
if (!Prev || !Prev->isStaticDataMember()) {
// We expect to see a static data member here.
Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_not_known)
<< Name;
for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
P != PEnd; ++P)
Diag((*P)->getLocation(), diag::note_explicit_instantiation_here);
return true;
}
if (!Prev->getInstantiatedFromStaticDataMember()) {
// FIXME: Check for explicit specialization?
Diag(D.getIdentifierLoc(),
diag::err_explicit_instantiation_data_member_not_instantiated)
<< Prev;
Diag(Prev->getLocation(), diag::note_explicit_instantiation_here);
// FIXME: Can we provide a note showing where this was declared?
return true;
}
} else {
// Explicitly instantiate a variable template.
// C++1y [dcl.spec.auto]p6:
// ... A program that uses auto or decltype(auto) in a context not
// explicitly allowed in this section is ill-formed.
//
// This includes auto-typed variable template instantiations.
if (R->isUndeducedType()) {
Diag(T->getTypeLoc().getBeginLoc(),
diag::err_auto_not_allowed_var_inst);
return true;
}
if (D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId) {
// C++1y [temp.explicit]p3:
// If the explicit instantiation is for a variable, the unqualified-id
// in the declaration shall be a template-id.
Diag(D.getIdentifierLoc(),
diag::err_explicit_instantiation_without_template_id)
<< PrevTemplate;
Diag(PrevTemplate->getLocation(),
diag::note_explicit_instantiation_here);
return true;
}
// Translate the parser's template argument list into our AST format.
TemplateArgumentListInfo TemplateArgs =
makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
DeclResult Res = CheckVarTemplateId(PrevTemplate, TemplateLoc,
D.getIdentifierLoc(), TemplateArgs);
if (Res.isInvalid())
return true;
if (!Res.isUsable()) {
// We somehow specified dependent template arguments in an explicit
// instantiation. This should probably only happen during error
// recovery.
Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_dependent);
return true;
}
// Ignore access control bits, we don't need them for redeclaration
// checking.
Prev = cast<VarDecl>(Res.get());
}
// C++0x [temp.explicit]p2:
// If the explicit instantiation is for a member function, a member class
// or a static data member of a class template specialization, the name of
// the class template specialization in the qualified-id for the member
// name shall be a simple-template-id.
//
// C++98 has the same restriction, just worded differently.
//
// This does not apply to variable template specializations, where the
// template-id is in the unqualified-id instead.
if (!ScopeSpecifierHasTemplateId(D.getCXXScopeSpec()) && !PrevTemplate)
Diag(D.getIdentifierLoc(),
diag::ext_explicit_instantiation_without_qualified_id)
<< Prev << D.getCXXScopeSpec().getRange();
CheckExplicitInstantiation(*this, Prev, D.getIdentifierLoc(), true, TSK);
// Verify that it is okay to explicitly instantiate here.
TemplateSpecializationKind PrevTSK = Prev->getTemplateSpecializationKind();
SourceLocation POI = Prev->getPointOfInstantiation();
bool HasNoEffect = false;
if (CheckSpecializationInstantiationRedecl(D.getIdentifierLoc(), TSK, Prev,
PrevTSK, POI, HasNoEffect))
return true;
if (!HasNoEffect) {
// Instantiate static data member or variable template.
Prev->setTemplateSpecializationKind(TSK, D.getIdentifierLoc());
// Merge attributes.
ProcessDeclAttributeList(S, Prev, D.getDeclSpec().getAttributes());
if (TSK == TSK_ExplicitInstantiationDefinition)
InstantiateVariableDefinition(D.getIdentifierLoc(), Prev);
}
// Check the new variable specialization against the parsed input.
if (PrevTemplate && !Context.hasSameType(Prev->getType(), R)) {
Diag(T->getTypeLoc().getBeginLoc(),
diag::err_invalid_var_template_spec_type)
<< 0 << PrevTemplate << R << Prev->getType();
Diag(PrevTemplate->getLocation(), diag::note_template_declared_here)
<< 2 << PrevTemplate->getDeclName();
return true;
}
// FIXME: Create an ExplicitInstantiation node?
return (Decl*) nullptr;
}
// If the declarator is a template-id, translate the parser's template
// argument list into our AST format.
bool HasExplicitTemplateArgs = false;
TemplateArgumentListInfo TemplateArgs;
if (D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId) {
TemplateArgs = makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
HasExplicitTemplateArgs = true;
}
// C++ [temp.explicit]p1:
// A [...] function [...] can be explicitly instantiated from its template.
// A member function [...] of a class template can be explicitly
// instantiated from the member definition associated with its class
// template.
UnresolvedSet<8> TemplateMatches;
FunctionDecl *NonTemplateMatch = nullptr;
TemplateSpecCandidateSet FailedCandidates(D.getIdentifierLoc());
for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
P != PEnd; ++P) {
NamedDecl *Prev = *P;
if (!HasExplicitTemplateArgs) {
if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Prev)) {
QualType Adjusted = adjustCCAndNoReturn(R, Method->getType(),
/*AdjustExceptionSpec*/true);
if (Context.hasSameUnqualifiedType(Method->getType(), Adjusted)) {
if (Method->getPrimaryTemplate()) {
TemplateMatches.addDecl(Method, P.getAccess());
} else {
// FIXME: Can this assert ever happen? Needs a test.
assert(!NonTemplateMatch && "Multiple NonTemplateMatches");
NonTemplateMatch = Method;
}
}
}
}
FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Prev);
if (!FunTmpl)
continue;
TemplateDeductionInfo Info(FailedCandidates.getLocation());
FunctionDecl *Specialization = nullptr;
if (TemplateDeductionResult TDK
= DeduceTemplateArguments(FunTmpl,
(HasExplicitTemplateArgs ? &TemplateArgs
: nullptr),
R, Specialization, Info)) {
// Keep track of almost-matches.
FailedCandidates.addCandidate()
.set(P.getPair(), FunTmpl->getTemplatedDecl(),
MakeDeductionFailureInfo(Context, TDK, Info));
(void)TDK;
continue;
}
// Target attributes are part of the cuda function signature, so
// the cuda target of the instantiated function must match that of its
// template. Given that C++ template deduction does not take
// target attributes into account, we reject candidates here that
// have a different target.
if (LangOpts.CUDA &&
IdentifyCUDATarget(Specialization,
/* IgnoreImplicitHDAttr = */ true) !=
IdentifyCUDATarget(D.getDeclSpec().getAttributes())) {
FailedCandidates.addCandidate().set(
P.getPair(), FunTmpl->getTemplatedDecl(),
MakeDeductionFailureInfo(Context, TDK_CUDATargetMismatch, Info));
continue;
}
TemplateMatches.addDecl(Specialization, P.getAccess());
}
FunctionDecl *Specialization = NonTemplateMatch;
if (!Specialization) {
// Find the most specialized function template specialization.
UnresolvedSetIterator Result = getMostSpecialized(
TemplateMatches.begin(), TemplateMatches.end(), FailedCandidates,
D.getIdentifierLoc(),
PDiag(diag::err_explicit_instantiation_not_known) << Name,
PDiag(diag::err_explicit_instantiation_ambiguous) << Name,
PDiag(diag::note_explicit_instantiation_candidate));
if (Result == TemplateMatches.end())
return true;
// Ignore access control bits, we don't need them for redeclaration checking.
Specialization = cast<FunctionDecl>(*Result);
}
// C++11 [except.spec]p4
// In an explicit instantiation an exception-specification may be specified,
// but is not required.
// If an exception-specification is specified in an explicit instantiation
// directive, it shall be compatible with the exception-specifications of
// other declarations of that function.
if (auto *FPT = R->getAs<FunctionProtoType>())
if (FPT->hasExceptionSpec()) {
unsigned DiagID =
diag::err_mismatched_exception_spec_explicit_instantiation;
if (getLangOpts().MicrosoftExt)
DiagID = diag::ext_mismatched_exception_spec_explicit_instantiation;
bool Result = CheckEquivalentExceptionSpec(
PDiag(DiagID) << Specialization->getType(),
PDiag(diag::note_explicit_instantiation_here),
Specialization->getType()->getAs<FunctionProtoType>(),
Specialization->getLocation(), FPT, D.getBeginLoc());
// In Microsoft mode, mismatching exception specifications just cause a
// warning.
if (!getLangOpts().MicrosoftExt && Result)
return true;
}
if (Specialization->getTemplateSpecializationKind() == TSK_Undeclared) {
Diag(D.getIdentifierLoc(),
diag::err_explicit_instantiation_member_function_not_instantiated)
<< Specialization
<< (Specialization->getTemplateSpecializationKind() ==
TSK_ExplicitSpecialization);
Diag(Specialization->getLocation(), diag::note_explicit_instantiation_here);
return true;
}
FunctionDecl *PrevDecl = Specialization->getPreviousDecl();
if (!PrevDecl && Specialization->isThisDeclarationADefinition())
PrevDecl = Specialization;
if (PrevDecl) {
bool HasNoEffect = false;
if (CheckSpecializationInstantiationRedecl(D.getIdentifierLoc(), TSK,
PrevDecl,
PrevDecl->getTemplateSpecializationKind(),
PrevDecl->getPointOfInstantiation(),
HasNoEffect))
return true;
// FIXME: We may still want to build some representation of this
// explicit specialization.
if (HasNoEffect)
return (Decl*) nullptr;
}
// HACK: libc++ has a bug where it attempts to explicitly instantiate the
// functions
// valarray<size_t>::valarray(size_t) and
// valarray<size_t>::~valarray()
// that it declared to have internal linkage with the internal_linkage
// attribute. Ignore the explicit instantiation declaration in this case.
if (Specialization->hasAttr<InternalLinkageAttr>() &&
TSK == TSK_ExplicitInstantiationDeclaration) {
if (auto *RD = dyn_cast<CXXRecordDecl>(Specialization->getDeclContext()))
if (RD->getIdentifier() && RD->getIdentifier()->isStr("valarray") &&
RD->isInStdNamespace())
return (Decl*) nullptr;
}
ProcessDeclAttributeList(S, Specialization, D.getDeclSpec().getAttributes());
// In MSVC mode, dllimported explicit instantiation definitions are treated as
// instantiation declarations.
if (TSK == TSK_ExplicitInstantiationDefinition &&
Specialization->hasAttr<DLLImportAttr>() &&
Context.getTargetInfo().getCXXABI().isMicrosoft())
TSK = TSK_ExplicitInstantiationDeclaration;
Specialization->setTemplateSpecializationKind(TSK, D.getIdentifierLoc());
if (Specialization->isDefined()) {
// Let the ASTConsumer know that this function has been explicitly
// instantiated now, and its linkage might have changed.
Consumer.HandleTopLevelDecl(DeclGroupRef(Specialization));
} else if (TSK == TSK_ExplicitInstantiationDefinition)
InstantiateFunctionDefinition(D.getIdentifierLoc(), Specialization);
// C++0x [temp.explicit]p2:
// If the explicit instantiation is for a member function, a member class
// or a static data member of a class template specialization, the name of
// the class template specialization in the qualified-id for the member
// name shall be a simple-template-id.
//
// C++98 has the same restriction, just worded differently.
FunctionTemplateDecl *FunTmpl = Specialization->getPrimaryTemplate();
if (D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId && !FunTmpl &&
D.getCXXScopeSpec().isSet() &&
!ScopeSpecifierHasTemplateId(D.getCXXScopeSpec()))
Diag(D.getIdentifierLoc(),
diag::ext_explicit_instantiation_without_qualified_id)
<< Specialization << D.getCXXScopeSpec().getRange();
CheckExplicitInstantiation(
*this,
FunTmpl ? (NamedDecl *)FunTmpl
: Specialization->getInstantiatedFromMemberFunction(),
D.getIdentifierLoc(), D.getCXXScopeSpec().isSet(), TSK);
// FIXME: Create some kind of ExplicitInstantiationDecl here.
return (Decl*) nullptr;
}
TypeResult
Sema::ActOnDependentTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
const CXXScopeSpec &SS, IdentifierInfo *Name,
SourceLocation TagLoc, SourceLocation NameLoc) {
// This has to hold, because SS is expected to be defined.
assert(Name && "Expected a name in a dependent tag");
NestedNameSpecifier *NNS = SS.getScopeRep();
if (!NNS)
return true;
TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
if (TUK == TUK_Declaration || TUK == TUK_Definition) {
Diag(NameLoc, diag::err_dependent_tag_decl)
<< (TUK == TUK_Definition) << Kind << SS.getRange();
return true;
}
// Create the resulting type.
ElaboratedTypeKeyword Kwd = TypeWithKeyword::getKeywordForTagTypeKind(Kind);
QualType Result = Context.getDependentNameType(Kwd, NNS, Name);
// Create type-source location information for this type.
TypeLocBuilder TLB;
DependentNameTypeLoc TL = TLB.push<DependentNameTypeLoc>(Result);
TL.setElaboratedKeywordLoc(TagLoc);
TL.setQualifierLoc(SS.getWithLocInContext(Context));
TL.setNameLoc(NameLoc);
return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
}
TypeResult
Sema::ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
const CXXScopeSpec &SS, const IdentifierInfo &II,
SourceLocation IdLoc) {
if (SS.isInvalid())
return true;
if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
Diag(TypenameLoc,
getLangOpts().CPlusPlus11 ?
diag::warn_cxx98_compat_typename_outside_of_template :
diag::ext_typename_outside_of_template)
<< FixItHint::CreateRemoval(TypenameLoc);
NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
TypeSourceInfo *TSI = nullptr;
QualType T = CheckTypenameType(TypenameLoc.isValid()? ETK_Typename : ETK_None,
TypenameLoc, QualifierLoc, II, IdLoc, &TSI,
/*DeducedTSTContext=*/true);
if (T.isNull())
return true;
return CreateParsedType(T, TSI);
}
TypeResult
Sema::ActOnTypenameType(Scope *S,
SourceLocation TypenameLoc,
const CXXScopeSpec &SS,
SourceLocation TemplateKWLoc,
TemplateTy TemplateIn,
IdentifierInfo *TemplateII,
SourceLocation TemplateIILoc,
SourceLocation LAngleLoc,
ASTTemplateArgsPtr TemplateArgsIn,
SourceLocation RAngleLoc) {
if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
Diag(TypenameLoc,
getLangOpts().CPlusPlus11 ?
diag::warn_cxx98_compat_typename_outside_of_template :
diag::ext_typename_outside_of_template)
<< FixItHint::CreateRemoval(TypenameLoc);
// Strangely, non-type results are not ignored by this lookup, so the
// program is ill-formed if it finds an injected-class-name.
if (TypenameLoc.isValid()) {
auto *LookupRD =
dyn_cast_or_null<CXXRecordDecl>(computeDeclContext(SS, false));
if (LookupRD && LookupRD->getIdentifier() == TemplateII) {
Diag(TemplateIILoc,
diag::ext_out_of_line_qualified_id_type_names_constructor)
<< TemplateII << 0 /*injected-class-name used as template name*/
<< (TemplateKWLoc.isValid() ? 1 : 0 /*'template'/'typename' keyword*/);
}
}
// Translate the parser's template argument list in our AST format.
TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
translateTemplateArguments(TemplateArgsIn, TemplateArgs);
TemplateName Template = TemplateIn.get();
if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
// Construct a dependent template specialization type.
assert(DTN && "dependent template has non-dependent name?");
assert(DTN->getQualifier() == SS.getScopeRep());
QualType T = Context.getDependentTemplateSpecializationType(ETK_Typename,
DTN->getQualifier(),
DTN->getIdentifier(),
TemplateArgs);
// Create source-location information for this type.
TypeLocBuilder Builder;
DependentTemplateSpecializationTypeLoc SpecTL
= Builder.push<DependentTemplateSpecializationTypeLoc>(T);
SpecTL.setElaboratedKeywordLoc(TypenameLoc);
SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
SpecTL.setTemplateNameLoc(TemplateIILoc);
SpecTL.setLAngleLoc(LAngleLoc);
SpecTL.setRAngleLoc(RAngleLoc);
for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
}
QualType T = CheckTemplateIdType(Template, TemplateIILoc, TemplateArgs);
if (T.isNull())
return true;
// Provide source-location information for the template specialization type.
TypeLocBuilder Builder;
TemplateSpecializationTypeLoc SpecTL
= Builder.push<TemplateSpecializationTypeLoc>(T);
SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
SpecTL.setTemplateNameLoc(TemplateIILoc);
SpecTL.setLAngleLoc(LAngleLoc);
SpecTL.setRAngleLoc(RAngleLoc);
for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
T = Context.getElaboratedType(ETK_Typename, SS.getScopeRep(), T);
ElaboratedTypeLoc TL = Builder.push<ElaboratedTypeLoc>(T);
TL.setElaboratedKeywordLoc(TypenameLoc);
TL.setQualifierLoc(SS.getWithLocInContext(Context));
TypeSourceInfo *TSI = Builder.getTypeSourceInfo(Context, T);
return CreateParsedType(T, TSI);
}
/// Determine whether this failed name lookup should be treated as being
/// disabled by a usage of std::enable_if.
static bool isEnableIf(NestedNameSpecifierLoc NNS, const IdentifierInfo &II,
SourceRange &CondRange, Expr *&Cond) {
// We must be looking for a ::type...
if (!II.isStr("type"))
return false;
// ... within an explicitly-written template specialization...
if (!NNS || !NNS.getNestedNameSpecifier()->getAsType())
return false;
TypeLoc EnableIfTy = NNS.getTypeLoc();
TemplateSpecializationTypeLoc EnableIfTSTLoc =
EnableIfTy.getAs<TemplateSpecializationTypeLoc>();
if (!EnableIfTSTLoc || EnableIfTSTLoc.getNumArgs() == 0)
return false;
const TemplateSpecializationType *EnableIfTST = EnableIfTSTLoc.getTypePtr();
// ... which names a complete class template declaration...
const TemplateDecl *EnableIfDecl =
EnableIfTST->getTemplateName().getAsTemplateDecl();
if (!EnableIfDecl || EnableIfTST->isIncompleteType())
return false;
// ... called "enable_if".
const IdentifierInfo *EnableIfII =
EnableIfDecl->getDeclName().getAsIdentifierInfo();
if (!EnableIfII || !EnableIfII->isStr("enable_if"))
return false;
// Assume the first template argument is the condition.
CondRange = EnableIfTSTLoc.getArgLoc(0).getSourceRange();
// Dig out the condition.
Cond = nullptr;
if (EnableIfTSTLoc.getArgLoc(0).getArgument().getKind()
!= TemplateArgument::Expression)
return true;
Cond = EnableIfTSTLoc.getArgLoc(0).getSourceExpression();
// Ignore Boolean literals; they add no value.
if (isa<CXXBoolLiteralExpr>(Cond->IgnoreParenCasts()))
Cond = nullptr;
return true;
}
QualType
Sema::CheckTypenameType(ElaboratedTypeKeyword Keyword,
SourceLocation KeywordLoc,
NestedNameSpecifierLoc QualifierLoc,
const IdentifierInfo &II,
SourceLocation IILoc,
TypeSourceInfo **TSI,
bool DeducedTSTContext) {
QualType T = CheckTypenameType(Keyword, KeywordLoc, QualifierLoc, II, IILoc,
DeducedTSTContext);
if (T.isNull())
return QualType();
*TSI = Context.CreateTypeSourceInfo(T);
if (isa<DependentNameType>(T)) {
DependentNameTypeLoc TL =
(*TSI)->getTypeLoc().castAs<DependentNameTypeLoc>();
TL.setElaboratedKeywordLoc(KeywordLoc);
TL.setQualifierLoc(QualifierLoc);
TL.setNameLoc(IILoc);
} else {
ElaboratedTypeLoc TL = (*TSI)->getTypeLoc().castAs<ElaboratedTypeLoc>();
TL.setElaboratedKeywordLoc(KeywordLoc);
TL.setQualifierLoc(QualifierLoc);
TL.getNamedTypeLoc().castAs<TypeSpecTypeLoc>().setNameLoc(IILoc);
}
return T;
}
/// Build the type that describes a C++ typename specifier,
/// e.g., "typename T::type".
QualType
Sema::CheckTypenameType(ElaboratedTypeKeyword Keyword,
SourceLocation KeywordLoc,
NestedNameSpecifierLoc QualifierLoc,
const IdentifierInfo &II,
SourceLocation IILoc, bool DeducedTSTContext) {
CXXScopeSpec SS;
SS.Adopt(QualifierLoc);
DeclContext *Ctx = nullptr;
if (QualifierLoc) {
Ctx = computeDeclContext(SS);
if (!Ctx) {
// If the nested-name-specifier is dependent and couldn't be
// resolved to a type, build a typename type.
assert(QualifierLoc.getNestedNameSpecifier()->isDependent());
return Context.getDependentNameType(Keyword,
QualifierLoc.getNestedNameSpecifier(),
&II);
}
// If the nested-name-specifier refers to the current instantiation,
// the "typename" keyword itself is superfluous. In C++03, the
// program is actually ill-formed. However, DR 382 (in C++0x CD1)
// allows such extraneous "typename" keywords, and we retroactively
// apply this DR to C++03 code with only a warning. In any case we continue.
if (RequireCompleteDeclContext(SS, Ctx))
return QualType();
}
DeclarationName Name(&II);
LookupResult Result(*this, Name, IILoc, LookupOrdinaryName);
if (Ctx)
LookupQualifiedName(Result, Ctx, SS);
else
LookupName(Result, CurScope);
unsigned DiagID = 0;
Decl *Referenced = nullptr;
switch (Result.getResultKind()) {
case LookupResult::NotFound: {
// If we're looking up 'type' within a template named 'enable_if', produce
// a more specific diagnostic.
SourceRange CondRange;
Expr *Cond = nullptr;
if (Ctx && isEnableIf(QualifierLoc, II, CondRange, Cond)) {
// If we have a condition, narrow it down to the specific failed
// condition.
if (Cond) {
Expr *FailedCond;
std::string FailedDescription;
std::tie(FailedCond, FailedDescription) =
findFailedBooleanCondition(Cond);
Diag(FailedCond->getExprLoc(),
diag::err_typename_nested_not_found_requirement)
<< FailedDescription
<< FailedCond->getSourceRange();
return QualType();
}
Diag(CondRange.getBegin(),
diag::err_typename_nested_not_found_enable_if)
<< Ctx << CondRange;
return QualType();
}
DiagID = Ctx ? diag::err_typename_nested_not_found
: diag::err_unknown_typename;
break;
}
case LookupResult::FoundUnresolvedValue: {
// We found a using declaration that is a value. Most likely, the using
// declaration itself is meant to have the 'typename' keyword.
SourceRange FullRange(KeywordLoc.isValid() ? KeywordLoc : SS.getBeginLoc(),
IILoc);
Diag(IILoc, diag::err_typename_refers_to_using_value_decl)
<< Name << Ctx << FullRange;
if (UnresolvedUsingValueDecl *Using
= dyn_cast<UnresolvedUsingValueDecl>(Result.getRepresentativeDecl())){
SourceLocation Loc = Using->getQualifierLoc().getBeginLoc();
Diag(Loc, diag::note_using_value_decl_missing_typename)
<< FixItHint::CreateInsertion(Loc, "typename ");
}
}
// Fall through to create a dependent typename type, from which we can recover
// better.
LLVM_FALLTHROUGH;
case LookupResult::NotFoundInCurrentInstantiation:
// Okay, it's a member of an unknown instantiation.
return Context.getDependentNameType(Keyword,
QualifierLoc.getNestedNameSpecifier(),
&II);
case LookupResult::Found:
if (TypeDecl *Type = dyn_cast<TypeDecl>(Result.getFoundDecl())) {
// C++ [class.qual]p2:
// In a lookup in which function names are not ignored and the
// nested-name-specifier nominates a class C, if the name specified
// after the nested-name-specifier, when looked up in C, is the
// injected-class-name of C [...] then the name is instead considered
// to name the constructor of class C.
//
// Unlike in an elaborated-type-specifier, function names are not ignored
// in typename-specifier lookup. However, they are ignored in all the
// contexts where we form a typename type with no keyword (that is, in
// mem-initializer-ids, base-specifiers, and elaborated-type-specifiers).
//
// FIXME: That's not strictly true: mem-initializer-id lookup does not
// ignore functions, but that appears to be an oversight.
auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(Ctx);
auto *FoundRD = dyn_cast<CXXRecordDecl>(Type);
if (Keyword == ETK_Typename && LookupRD && FoundRD &&
FoundRD->isInjectedClassName() &&
declaresSameEntity(LookupRD, cast<Decl>(FoundRD->getParent())))
Diag(IILoc, diag::ext_out_of_line_qualified_id_type_names_constructor)
<< &II << 1 << 0 /*'typename' keyword used*/;
// We found a type. Build an ElaboratedType, since the
// typename-specifier was just sugar.
MarkAnyDeclReferenced(Type->getLocation(), Type, /*OdrUse=*/false);
return Context.getElaboratedType(Keyword,
QualifierLoc.getNestedNameSpecifier(),
Context.getTypeDeclType(Type));
}
// C++ [dcl.type.simple]p2:
// A type-specifier of the form
// typename[opt] nested-name-specifier[opt] template-name
// is a placeholder for a deduced class type [...].
if (getLangOpts().CPlusPlus17) {
if (auto *TD = getAsTypeTemplateDecl(Result.getFoundDecl())) {
if (!DeducedTSTContext) {
QualType T(QualifierLoc
? QualifierLoc.getNestedNameSpecifier()->getAsType()
: nullptr, 0);
if (!T.isNull())
Diag(IILoc, diag::err_dependent_deduced_tst)
<< (int)getTemplateNameKindForDiagnostics(TemplateName(TD)) << T;
else
Diag(IILoc, diag::err_deduced_tst)
<< (int)getTemplateNameKindForDiagnostics(TemplateName(TD));
Diag(TD->getLocation(), diag::note_template_decl_here);
return QualType();
}
return Context.getElaboratedType(
Keyword, QualifierLoc.getNestedNameSpecifier(),
Context.getDeducedTemplateSpecializationType(TemplateName(TD),
QualType(), false));
}
}
DiagID = Ctx ? diag::err_typename_nested_not_type
: diag::err_typename_not_type;
Referenced = Result.getFoundDecl();
break;
case LookupResult::FoundOverloaded:
DiagID = Ctx ? diag::err_typename_nested_not_type
: diag::err_typename_not_type;
Referenced = *Result.begin();
break;
case LookupResult::Ambiguous:
return QualType();
}
// If we get here, it's because name lookup did not find a
// type. Emit an appropriate diagnostic and return an error.
SourceRange FullRange(KeywordLoc.isValid() ? KeywordLoc : SS.getBeginLoc(),
IILoc);
if (Ctx)
Diag(IILoc, DiagID) << FullRange << Name << Ctx;
else
Diag(IILoc, DiagID) << FullRange << Name;
if (Referenced)
Diag(Referenced->getLocation(),
Ctx ? diag::note_typename_member_refers_here
: diag::note_typename_refers_here)
<< Name;
return QualType();
}
namespace {
// See Sema::RebuildTypeInCurrentInstantiation
class CurrentInstantiationRebuilder
: public TreeTransform<CurrentInstantiationRebuilder> {
SourceLocation Loc;
DeclarationName Entity;
public:
typedef TreeTransform<CurrentInstantiationRebuilder> inherited;
CurrentInstantiationRebuilder(Sema &SemaRef,
SourceLocation Loc,
DeclarationName Entity)
: TreeTransform<CurrentInstantiationRebuilder>(SemaRef),
Loc(Loc), Entity(Entity) { }
/// Determine whether the given type \p T has already been
/// transformed.
///
/// For the purposes of type reconstruction, a type has already been
/// transformed if it is NULL or if it is not dependent.
bool AlreadyTransformed(QualType T) {
return T.isNull() || !T->isInstantiationDependentType();
}
/// Returns the location of the entity whose type is being
/// rebuilt.
SourceLocation getBaseLocation() { return Loc; }
/// Returns the name of the entity whose type is being rebuilt.
DeclarationName getBaseEntity() { return Entity; }
/// Sets the "base" location and entity when that
/// information is known based on another transformation.
void setBase(SourceLocation Loc, DeclarationName Entity) {
this->Loc = Loc;
this->Entity = Entity;
}
ExprResult TransformLambdaExpr(LambdaExpr *E) {
// Lambdas never need to be transformed.
return E;
}
};
} // end anonymous namespace
/// Rebuilds a type within the context of the current instantiation.
///
/// The type \p T is part of the type of an out-of-line member definition of
/// a class template (or class template partial specialization) that was parsed
/// and constructed before we entered the scope of the class template (or
/// partial specialization thereof). This routine will rebuild that type now
/// that we have entered the declarator's scope, which may produce different
/// canonical types, e.g.,
///
/// \code
/// template<typename T>
/// struct X {
/// typedef T* pointer;
/// pointer data();
/// };
///
/// template<typename T>
/// typename X<T>::pointer X<T>::data() { ... }
/// \endcode
///
/// Here, the type "typename X<T>::pointer" will be created as a DependentNameType,
/// since we do not know that we can look into X<T> when we parsed the type.
/// This function will rebuild the type, performing the lookup of "pointer"
/// in X<T> and returning an ElaboratedType whose canonical type is the same
/// as the canonical type of T*, allowing the return types of the out-of-line
/// definition and the declaration to match.
TypeSourceInfo *Sema::RebuildTypeInCurrentInstantiation(TypeSourceInfo *T,
SourceLocation Loc,
DeclarationName Name) {
if (!T || !T->getType()->isInstantiationDependentType())
return T;
CurrentInstantiationRebuilder Rebuilder(*this, Loc, Name);
return Rebuilder.TransformType(T);
}
ExprResult Sema::RebuildExprInCurrentInstantiation(Expr *E) {
CurrentInstantiationRebuilder Rebuilder(*this, E->getExprLoc(),
DeclarationName());
return Rebuilder.TransformExpr(E);
}
bool Sema::RebuildNestedNameSpecifierInCurrentInstantiation(CXXScopeSpec &SS) {
if (SS.isInvalid())
return true;
NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
CurrentInstantiationRebuilder Rebuilder(*this, SS.getRange().getBegin(),
DeclarationName());
NestedNameSpecifierLoc Rebuilt
= Rebuilder.TransformNestedNameSpecifierLoc(QualifierLoc);
if (!Rebuilt)
return true;
SS.Adopt(Rebuilt);
return false;
}
/// Rebuild the template parameters now that we know we're in a current
/// instantiation.
bool Sema::RebuildTemplateParamsInCurrentInstantiation(
TemplateParameterList *Params) {
for (unsigned I = 0, N = Params->size(); I != N; ++I) {
Decl *Param = Params->getParam(I);
// There is nothing to rebuild in a type parameter.
if (isa<TemplateTypeParmDecl>(Param))
continue;
// Rebuild the template parameter list of a template template parameter.
if (TemplateTemplateParmDecl *TTP
= dyn_cast<TemplateTemplateParmDecl>(Param)) {
if (RebuildTemplateParamsInCurrentInstantiation(
TTP->getTemplateParameters()))
return true;
continue;
}
// Rebuild the type of a non-type template parameter.
NonTypeTemplateParmDecl *NTTP = cast<NonTypeTemplateParmDecl>(Param);
TypeSourceInfo *NewTSI
= RebuildTypeInCurrentInstantiation(NTTP->getTypeSourceInfo(),
NTTP->getLocation(),
NTTP->getDeclName());
if (!NewTSI)
return true;
if (NewTSI->getType()->isUndeducedType()) {
// C++17 [temp.dep.expr]p3:
// An id-expression is type-dependent if it contains
// - an identifier associated by name lookup with a non-type
// template-parameter declared with a type that contains a
// placeholder type (7.1.7.4),
NewTSI = SubstAutoTypeSourceInfoDependent(NewTSI);
}
if (NewTSI != NTTP->getTypeSourceInfo()) {
NTTP->setTypeSourceInfo(NewTSI);
NTTP->setType(NewTSI->getType());
}
}
return false;
}
/// Produces a formatted string that describes the binding of
/// template parameters to template arguments.
std::string
Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
const TemplateArgumentList &Args) {
return getTemplateArgumentBindingsText(Params, Args.data(), Args.size());
}
std::string
Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
const TemplateArgument *Args,
unsigned NumArgs) {
SmallString<128> Str;
llvm::raw_svector_ostream Out(Str);
if (!Params || Params->size() == 0 || NumArgs == 0)
return std::string();
for (unsigned I = 0, N = Params->size(); I != N; ++I) {
if (I >= NumArgs)
break;
if (I == 0)
Out << "[with ";
else
Out << ", ";
if (const IdentifierInfo *Id = Params->getParam(I)->getIdentifier()) {
Out << Id->getName();
} else {
Out << '$' << I;
}
Out << " = ";
Args[I].print(getPrintingPolicy(), Out,
TemplateParameterList::shouldIncludeTypeForArgument(
getPrintingPolicy(), Params, I));
}
Out << ']';
return std::string(Out.str());
}
void Sema::MarkAsLateParsedTemplate(FunctionDecl *FD, Decl *FnD,
CachedTokens &Toks) {
if (!FD)
return;
auto LPT = std::make_unique<LateParsedTemplate>();
// Take tokens to avoid allocations
LPT->Toks.swap(Toks);
LPT->D = FnD;
LateParsedTemplateMap.insert(std::make_pair(FD, std::move(LPT)));
FD->setLateTemplateParsed(true);
}
void Sema::UnmarkAsLateParsedTemplate(FunctionDecl *FD) {
if (!FD)
return;
FD->setLateTemplateParsed(false);
}
bool Sema::IsInsideALocalClassWithinATemplateFunction() {
DeclContext *DC = CurContext;
while (DC) {
if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(CurContext)) {
const FunctionDecl *FD = RD->isLocalClass();
return (FD && FD->getTemplatedKind() != FunctionDecl::TK_NonTemplate);
} else if (DC->isTranslationUnit() || DC->isNamespace())
return false;
DC = DC->getParent();
}
return false;
}
namespace {
/// Walk the path from which a declaration was instantiated, and check
/// that every explicit specialization along that path is visible. This enforces
/// C++ [temp.expl.spec]/6:
///
/// If a template, a member template or a member of a class template is
/// explicitly specialized then that specialization shall be declared before
/// the first use of that specialization that would cause an implicit
/// instantiation to take place, in every translation unit in which such a
/// use occurs; no diagnostic is required.
///
/// and also C++ [temp.class.spec]/1:
///
/// A partial specialization shall be declared before the first use of a
/// class template specialization that would make use of the partial
/// specialization as the result of an implicit or explicit instantiation
/// in every translation unit in which such a use occurs; no diagnostic is
/// required.
class ExplicitSpecializationVisibilityChecker {
Sema &S;
SourceLocation Loc;
llvm::SmallVector<Module *, 8> Modules;
public:
ExplicitSpecializationVisibilityChecker(Sema &S, SourceLocation Loc)
: S(S), Loc(Loc) {}
void check(NamedDecl *ND) {
if (auto *FD = dyn_cast<FunctionDecl>(ND))
return checkImpl(FD);
if (auto *RD = dyn_cast<CXXRecordDecl>(ND))
return checkImpl(RD);
if (auto *VD = dyn_cast<VarDecl>(ND))
return checkImpl(VD);
if (auto *ED = dyn_cast<EnumDecl>(ND))
return checkImpl(ED);
}
private:
void diagnose(NamedDecl *D, bool IsPartialSpec) {
auto Kind = IsPartialSpec ? Sema::MissingImportKind::PartialSpecialization
: Sema::MissingImportKind::ExplicitSpecialization;
const bool Recover = true;
// If we got a custom set of modules (because only a subset of the
// declarations are interesting), use them, otherwise let
// diagnoseMissingImport intelligently pick some.
if (Modules.empty())
S.diagnoseMissingImport(Loc, D, Kind, Recover);
else
S.diagnoseMissingImport(Loc, D, D->getLocation(), Modules, Kind, Recover);
}
// Check a specific declaration. There are three problematic cases:
//
// 1) The declaration is an explicit specialization of a template
// specialization.
// 2) The declaration is an explicit specialization of a member of an
// templated class.
// 3) The declaration is an instantiation of a template, and that template
// is an explicit specialization of a member of a templated class.
//
// We don't need to go any deeper than that, as the instantiation of the
// surrounding class / etc is not triggered by whatever triggered this
// instantiation, and thus should be checked elsewhere.
template<typename SpecDecl>
void checkImpl(SpecDecl *Spec) {
bool IsHiddenExplicitSpecialization = false;
if (Spec->getTemplateSpecializationKind() == TSK_ExplicitSpecialization) {
IsHiddenExplicitSpecialization =
Spec->getMemberSpecializationInfo()
? !S.hasVisibleMemberSpecialization(Spec, &Modules)
: !S.hasVisibleExplicitSpecialization(Spec, &Modules);
} else {
checkInstantiated(Spec);
}
if (IsHiddenExplicitSpecialization)
diagnose(Spec->getMostRecentDecl(), false);
}
void checkInstantiated(FunctionDecl *FD) {
if (auto *TD = FD->getPrimaryTemplate())
checkTemplate(TD);
}
void checkInstantiated(CXXRecordDecl *RD) {
auto *SD = dyn_cast<ClassTemplateSpecializationDecl>(RD);
if (!SD)
return;
auto From = SD->getSpecializedTemplateOrPartial();
if (auto *TD = From.dyn_cast<ClassTemplateDecl *>())
checkTemplate(TD);
else if (auto *TD =
From.dyn_cast<ClassTemplatePartialSpecializationDecl *>()) {
if (!S.hasVisibleDeclaration(TD))
diagnose(TD, true);
checkTemplate(TD);
}
}
void checkInstantiated(VarDecl *RD) {
auto *SD = dyn_cast<VarTemplateSpecializationDecl>(RD);
if (!SD)
return;
auto From = SD->getSpecializedTemplateOrPartial();
if (auto *TD = From.dyn_cast<VarTemplateDecl *>())
checkTemplate(TD);
else if (auto *TD =
From.dyn_cast<VarTemplatePartialSpecializationDecl *>()) {
if (!S.hasVisibleDeclaration(TD))
diagnose(TD, true);
checkTemplate(TD);
}
}
void checkInstantiated(EnumDecl *FD) {}
template<typename TemplDecl>
void checkTemplate(TemplDecl *TD) {
if (TD->isMemberSpecialization()) {
if (!S.hasVisibleMemberSpecialization(TD, &Modules))
diagnose(TD->getMostRecentDecl(), false);
}
}
};
} // end anonymous namespace
void Sema::checkSpecializationVisibility(SourceLocation Loc, NamedDecl *Spec) {
if (!getLangOpts().Modules)
return;
ExplicitSpecializationVisibilityChecker(*this, Loc).check(Spec);
}
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