Parse A::template B as an identifier rather than as a template-id with no

template arguments.

This fixes some cases where we'd incorrectly accept "A::template B" when B is a
kind of template that requires template arguments (in particular, a variable
template or a concept).

llvm-svn: 331013

clang/include/clang/Basic/DiagnosticParseKinds.td

@@ -633,6 +633,8 @@ def err_template_spec_syntax_non_template : Error<
   "<unused>|refers to a variable template|<unused>}1">;
 def err_id_after_template_in_nested_name_spec : Error<
   "expected template name after 'template' keyword in nested name specifier">;
+def err_unexpected_template_in_unqualified_id : Error<
+  "'template' keyword not permitted here">;
 def err_two_right_angle_brackets_need_space : Error<
   "a space is required between consecutive right angle brackets (use '> >')">;
 def err_right_angle_bracket_equal_needs_space : Error<

clang/include/clang/Parse/Parser.h

@@ -2544,12 +2544,11 @@ private:
   struct UsingDeclarator {
     SourceLocation TypenameLoc;
     CXXScopeSpec SS;
-    SourceLocation TemplateKWLoc;
     UnqualifiedId Name;
     SourceLocation EllipsisLoc;
 
     void clear() {
-      TypenameLoc = TemplateKWLoc = EllipsisLoc = SourceLocation();
+      TypenameLoc = EllipsisLoc = SourceLocation();
       SS.clear();
       Name.clear();
     }
@@ -2744,7 +2743,7 @@ public:
                           bool AllowConstructorName,
                           bool AllowDeductionGuide,
                           ParsedType ObjectType,
-                          SourceLocation& TemplateKWLoc,
+                          SourceLocation *TemplateKWLoc,
                           UnqualifiedId &Result);
 
 private:

clang/include/clang/Sema/Sema.h

@@ -6074,7 +6074,7 @@ public:
   TemplateNameKind isTemplateName(Scope *S,
                                   CXXScopeSpec &SS,
                                   bool hasTemplateKeyword,
-                                  UnqualifiedId &Name,
+                                  const UnqualifiedId &Name,
                                   ParsedType ObjectType,
                                   bool EnteringContext,
                                   TemplateTy &Template,
@@ -6244,7 +6244,7 @@ public:
 
   TemplateNameKind ActOnDependentTemplateName(
       Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
-      UnqualifiedId &Name, ParsedType ObjectType, bool EnteringContext,
+      const UnqualifiedId &Name, ParsedType ObjectType, bool EnteringContext,
       TemplateTy &Template, bool AllowInjectedClassName = false);
 
   DeclResult

clang/lib/Parse/ParseDecl.cpp

@@ -5600,12 +5600,11 @@ void Parser::ParseDirectDeclarator(Declarator &D) {
            D.getContext() == DeclaratorContext::MemberContext);
       }
 
-      SourceLocation TemplateKWLoc;
       bool HadScope = D.getCXXScopeSpec().isValid();
       if (ParseUnqualifiedId(D.getCXXScopeSpec(),
                              /*EnteringContext=*/true,
                              /*AllowDestructorName=*/true, AllowConstructorName,
-                             AllowDeductionGuide, nullptr, TemplateKWLoc,
+                             AllowDeductionGuide, nullptr, nullptr,
                              D.getName()) ||
           // Once we're past the identifier, if the scope was bad, mark the
           // whole declarator bad.

clang/lib/Parse/ParseDeclCXX.cpp

@@ -602,7 +602,7 @@ bool Parser::ParseUsingDeclarator(DeclaratorContext Context,
             /*AllowConstructorName=*/!(Tok.is(tok::identifier) &&
                                        NextToken().is(tok::equal)),
             /*AllowDeductionGuide=*/false,
-            nullptr, D.TemplateKWLoc, D.Name))
+            nullptr, nullptr, D.Name))
       return true;
   }
 
@@ -2476,7 +2476,7 @@ Parser::ParseCXXClassMemberDeclaration(AccessSpecifier AS,
       SourceLocation TemplateKWLoc;
       UnqualifiedId Name;
       if (ParseUnqualifiedId(SS, false, true, true, false, nullptr,
-                             TemplateKWLoc, Name)) {
+                             &TemplateKWLoc, Name)) {
         SkipUntil(tok::semi);
         return nullptr;
       }
@@ -2488,6 +2488,7 @@ Parser::ParseCXXClassMemberDeclaration(AccessSpecifier AS,
         return nullptr;
       }
 
+      // FIXME: We should do something with the 'template' keyword here.
       return DeclGroupPtrTy::make(DeclGroupRef(Actions.ActOnUsingDeclaration(
           getCurScope(), AS, /*UsingLoc*/ SourceLocation(),
           /*TypenameLoc*/ SourceLocation(), SS, Name,

clang/lib/Parse/ParseExpr.cpp

@@ -1755,7 +1755,7 @@ Parser::ParsePostfixExpressionSuffix(ExprResult LHS) {
                                     /*AllowConstructorName=*/
                                       getLangOpts().MicrosoftExt, 
                                     /*AllowDeductionGuide=*/false,
-                                    ObjectType, TemplateKWLoc, Name)) {
+                                    ObjectType, &TemplateKWLoc, Name)) {
         (void)Actions.CorrectDelayedTyposInExpr(LHS);
         LHS = ExprError();
       }

clang/lib/Parse/ParseExprCXX.cpp

@@ -553,7 +553,7 @@ ExprResult Parser::tryParseCXXIdExpression(CXXScopeSpec &SS, bool isAddressOfOpe
                          /*AllowDestructorName=*/false,
                          /*AllowConstructorName=*/false,
                          /*AllowDeductionGuide=*/false,
-                         /*ObjectType=*/nullptr, TemplateKWLoc, Name))
+                         /*ObjectType=*/nullptr, &TemplateKWLoc, Name))
     return ExprError();
 
   // This is only the direct operand of an & operator if it is not
@@ -2044,9 +2044,8 @@ bool Parser::ParseUnqualifiedIdTemplateId(CXXScopeSpec &SS,
                                           ParsedType ObjectType,
                                           UnqualifiedId &Id,
                                           bool AssumeTemplateId) {
-  assert((AssumeTemplateId || Tok.is(tok::less)) &&
+  assert(Tok.is(tok::less) && "Expected '<' to finish parsing a template-id");
-         "Expected '<' to finish parsing a template-id");
+
-  
   TemplateTy Template;
   TemplateNameKind TNK = TNK_Non_template;
   switch (Id.getKind()) {
@@ -2142,10 +2141,10 @@ bool Parser::ParseUnqualifiedIdTemplateId(CXXScopeSpec &SS,
   // Parse the enclosed template argument list.
   SourceLocation LAngleLoc, RAngleLoc;
   TemplateArgList TemplateArgs;
-  if (Tok.is(tok::less) && ParseTemplateIdAfterTemplateName(
+  if (ParseTemplateIdAfterTemplateName(true, LAngleLoc, TemplateArgs,
-                               true, LAngleLoc, TemplateArgs, RAngleLoc))
+                                       RAngleLoc))
     return true;
-  
+
   if (Id.getKind() == UnqualifiedIdKind::IK_Identifier ||
       Id.getKind() == UnqualifiedIdKind::IK_OperatorFunctionId ||
       Id.getKind() == UnqualifiedIdKind::IK_LiteralOperatorId) {
@@ -2465,16 +2464,23 @@ bool Parser::ParseUnqualifiedId(CXXScopeSpec &SS, bool EnteringContext,
                                 bool AllowConstructorName,
                                 bool AllowDeductionGuide,
                                 ParsedType ObjectType,
-                                SourceLocation& TemplateKWLoc,
+                                SourceLocation *TemplateKWLoc,
                                 UnqualifiedId &Result) {
+  if (TemplateKWLoc)
+    *TemplateKWLoc = SourceLocation();
 
   // Handle 'A::template B'. This is for template-ids which have not
   // already been annotated by ParseOptionalCXXScopeSpecifier().
   bool TemplateSpecified = false;
-  if (getLangOpts().CPlusPlus && Tok.is(tok::kw_template) &&
+  if (Tok.is(tok::kw_template)) {
-      (ObjectType || SS.isSet())) {
+    if (TemplateKWLoc && (ObjectType || SS.isSet())) {
-    TemplateSpecified = true;
+      TemplateSpecified = true;
-    TemplateKWLoc = ConsumeToken();
+      *TemplateKWLoc = ConsumeToken();
+    } else {
+      SourceLocation TemplateLoc = ConsumeToken();
+      Diag(TemplateLoc, diag::err_unexpected_template_in_unqualified_id)
+        << FixItHint::CreateRemoval(TemplateLoc);
+    }
   }
 
   // unqualified-id:
@@ -2513,11 +2519,18 @@ bool Parser::ParseUnqualifiedId(CXXScopeSpec &SS, bool EnteringContext,
     }
 
     // If the next token is a '<', we may have a template.
-    if (TemplateSpecified || Tok.is(tok::less))
+    TemplateTy Template;
-      return ParseUnqualifiedIdTemplateId(SS, TemplateKWLoc, Id, IdLoc,
+    if (Tok.is(tok::less))
-                                          EnteringContext, ObjectType,
+      return ParseUnqualifiedIdTemplateId(
-                                          Result, TemplateSpecified);
+          SS, TemplateKWLoc ? *TemplateKWLoc : SourceLocation(), Id, IdLoc,
-    
+          EnteringContext, ObjectType, Result, TemplateSpecified);
+    else if (TemplateSpecified &&
+             Actions.ActOnDependentTemplateName(
+                 getCurScope(), SS, *TemplateKWLoc, Result, ObjectType,
+                 EnteringContext, Template,
+                 /*AllowInjectedClassName*/ true) == TNK_Non_template)
+      return true;
+
     return false;
   }
   
@@ -2558,7 +2571,14 @@ bool Parser::ParseUnqualifiedId(CXXScopeSpec &SS, bool EnteringContext,
     // We have already parsed a template-id; consume the annotation token as
     // our unqualified-id.
     Result.setTemplateId(TemplateId);
-    TemplateKWLoc = TemplateId->TemplateKWLoc;
+    SourceLocation TemplateLoc = TemplateId->TemplateKWLoc;
+    if (TemplateLoc.isValid()) {
+      if (TemplateKWLoc && (ObjectType || SS.isSet()))
+        *TemplateKWLoc = TemplateLoc;
+      else
+        Diag(TemplateLoc, diag::err_unexpected_template_in_unqualified_id)
+            << FixItHint::CreateRemoval(TemplateLoc);
+    }
     ConsumeAnnotationToken();
     return false;
   }
@@ -2575,13 +2595,20 @@ bool Parser::ParseUnqualifiedId(CXXScopeSpec &SS, bool EnteringContext,
     // 
     //   template-id:
     //     operator-function-id < template-argument-list[opt] >
+    TemplateTy Template;
     if ((Result.getKind() == UnqualifiedIdKind::IK_OperatorFunctionId ||
          Result.getKind() == UnqualifiedIdKind::IK_LiteralOperatorId) &&
-        (TemplateSpecified || Tok.is(tok::less)))
+        Tok.is(tok::less))
-      return ParseUnqualifiedIdTemplateId(SS, TemplateKWLoc,
+      return ParseUnqualifiedIdTemplateId(
-                                          nullptr, SourceLocation(),
+          SS, TemplateKWLoc ? *TemplateKWLoc : SourceLocation(), nullptr,
-                                          EnteringContext, ObjectType,
+          SourceLocation(), EnteringContext, ObjectType, Result,
-                                          Result, TemplateSpecified);
+          TemplateSpecified);
+    else if (TemplateSpecified &&
+             Actions.ActOnDependentTemplateName(
+                 getCurScope(), SS, *TemplateKWLoc, Result, ObjectType,
+                 EnteringContext, Template,
+                 /*AllowInjectedClassName*/ true) == TNK_Non_template)
+      return true;
 
     return false;
   }
@@ -2649,12 +2676,11 @@ bool Parser::ParseUnqualifiedId(CXXScopeSpec &SS, bool EnteringContext,
     IdentifierInfo *ClassName = Tok.getIdentifierInfo();
     SourceLocation ClassNameLoc = ConsumeToken();
 
-    if (TemplateSpecified || Tok.is(tok::less)) {
+    if (Tok.is(tok::less)) {
       Result.setDestructorName(TildeLoc, nullptr, ClassNameLoc);
-      return ParseUnqualifiedIdTemplateId(SS, TemplateKWLoc,
+      return ParseUnqualifiedIdTemplateId(
-                                          ClassName, ClassNameLoc,
+          SS, TemplateKWLoc ? *TemplateKWLoc : SourceLocation(), ClassName,
-                                          EnteringContext, ObjectType,
+          ClassNameLoc, EnteringContext, ObjectType, Result, TemplateSpecified);
-                                          Result, TemplateSpecified);
     }
 
     // Note that this is a destructor name.

clang/lib/Parse/ParseOpenMP.cpp

@@ -1154,7 +1154,6 @@ bool Parser::ParseOpenMPSimpleVarList(
   // Read tokens while ')' or annot_pragma_openmp_end is not found.
   while (Tok.isNot(tok::r_paren) && Tok.isNot(tok::annot_pragma_openmp_end)) {
     CXXScopeSpec SS;
-    SourceLocation TemplateKWLoc;
     UnqualifiedId Name;
     // Read var name.
     Token PrevTok = Tok;
@@ -1166,7 +1165,7 @@ bool Parser::ParseOpenMPSimpleVarList(
       SkipUntil(tok::comma, tok::r_paren, tok::annot_pragma_openmp_end,
                 StopBeforeMatch);
     } else if (ParseUnqualifiedId(SS, false, false, false, false, nullptr,
-                                  TemplateKWLoc, Name)) {
+                                  nullptr, Name)) {
       IsCorrect = false;
       SkipUntil(tok::comma, tok::r_paren, tok::annot_pragma_openmp_end,
                 StopBeforeMatch);
@@ -1648,7 +1647,6 @@ OMPClause *Parser::ParseOpenMPSingleExprWithArgClause(OpenMPClauseKind Kind,
 
 static bool ParseReductionId(Parser &P, CXXScopeSpec &ReductionIdScopeSpec,
                              UnqualifiedId &ReductionId) {
-  SourceLocation TemplateKWLoc;
   if (ReductionIdScopeSpec.isEmpty()) {
     auto OOK = OO_None;
     switch (P.getCurToken().getKind()) {
@@ -1690,7 +1688,7 @@ static bool ParseReductionId(Parser &P, CXXScopeSpec &ReductionIdScopeSpec,
                               /*AllowDestructorName*/ false,
                               /*AllowConstructorName*/ false,
                               /*AllowDeductionGuide*/ false,
-                              nullptr, TemplateKWLoc, ReductionId);
+                              nullptr, nullptr, ReductionId);
 }
 
 /// Parses clauses with list.

clang/lib/Parse/ParseStmtAsm.cpp

@@ -239,7 +239,7 @@ ExprResult Parser::ParseMSAsmIdentifier(llvm::SmallVectorImpl<Token> &LineToks,
                                  /*AllowDestructorName=*/false,
                                  /*AllowConstructorName=*/false,
                                  /*AllowDeductionGuide=*/false,
-                                 /*ObjectType=*/nullptr, TemplateKWLoc, Id);
+                                 /*ObjectType=*/nullptr, &TemplateKWLoc, Id);
     // Perform the lookup.
     Result = Actions.LookupInlineAsmIdentifier(SS, TemplateKWLoc, Id,
                                                IsUnevaluatedContext);

clang/lib/Parse/Parser.cpp

@@ -2002,7 +2002,7 @@ bool Parser::ParseMicrosoftIfExistsCondition(IfExistsCondition& Result) {
   if (ParseUnqualifiedId(
           Result.SS, /*EnteringContext*/false, /*AllowDestructorName*/true,
           /*AllowConstructorName*/true, /*AllowDeductionGuide*/false, nullptr,
-          TemplateKWLoc, Result.Name)) {
+          &TemplateKWLoc, Result.Name)) {
     T.skipToEnd();
     return true;
   }

clang/lib/Sema/SemaExpr.cpp

@@ -2080,7 +2080,7 @@ Sema::ActOnIdExpression(Scope *S, CXXScopeSpec &SS,
                  (Id.getKind() == UnqualifiedIdKind::IK_ImplicitSelfParam)
                      ? LookupObjCImplicitSelfParam
                      : LookupOrdinaryName);
-  if (TemplateArgs) {
+  if (TemplateKWLoc.isValid() || TemplateArgs) {
     // Lookup the template name again to correctly establish the context in
     // which it was found. This is really unfortunate as we already did the
     // lookup to determine that it was a template name in the first place. If
@@ -2089,7 +2089,7 @@ Sema::ActOnIdExpression(Scope *S, CXXScopeSpec &SS,
     bool MemberOfUnknownSpecialization;
     LookupTemplateName(R, S, SS, QualType(), /*EnteringContext=*/false,
                        MemberOfUnknownSpecialization);
-    
+
     if (MemberOfUnknownSpecialization ||
         (R.getResultKind() == LookupResult::NotFoundInCurrentInstantiation))
       return ActOnDependentIdExpression(SS, TemplateKWLoc, NameInfo,
@@ -2155,6 +2155,9 @@ Sema::ActOnIdExpression(Scope *S, CXXScopeSpec &SS,
       if (SS.isValid())
         CCC->setTypoNNS(SS.getScopeRep());
     }
+    // FIXME: DiagnoseEmptyLookup produces bad diagnostics if we're looking for
+    // a template name, but we happen to have always already looked up the name
+    // before we get here if it must be a template name.
     if (DiagnoseEmptyLookup(S, SS, R,
                             CCC ? std::move(CCC) : std::move(DefaultValidator),
                             nullptr, None, &TE)) {

clang/lib/Sema/SemaExprMember.cpp

@@ -759,9 +759,9 @@ Sema::BuildMemberReferenceExpr(Expr *Base, QualType BaseType,
     TypoExpr *TE = nullptr;
     QualType RecordTy = BaseType;
     if (IsArrow) RecordTy = RecordTy->getAs<PointerType>()->getPointeeType();
-    if (LookupMemberExprInRecord(*this, R, nullptr,
+    if (LookupMemberExprInRecord(
-                                 RecordTy->getAs<RecordType>(), OpLoc, IsArrow,
+            *this, R, nullptr, RecordTy->getAs<RecordType>(), OpLoc, IsArrow,
-                                 SS, TemplateArgs != nullptr, TE))
+            SS, TemplateKWLoc.isValid() || TemplateArgs != nullptr, TE))
       return ExprError();
     if (TE)
       return TE;
@@ -769,10 +769,10 @@ Sema::BuildMemberReferenceExpr(Expr *Base, QualType BaseType,
   // Explicit member accesses.
   } else {
     ExprResult BaseResult = Base;
-    ExprResult Result = LookupMemberExpr(
+    ExprResult Result =
-        *this, R, BaseResult, IsArrow, OpLoc, SS,
+        LookupMemberExpr(*this, R, BaseResult, IsArrow, OpLoc, SS,
-        ExtraArgs ? ExtraArgs->ObjCImpDecl : nullptr,
+                         ExtraArgs ? ExtraArgs->ObjCImpDecl : nullptr,
-        TemplateArgs != nullptr);
+                         TemplateKWLoc.isValid() || TemplateArgs != nullptr);
 
     if (BaseResult.isInvalid())
       return ExprError();

clang/lib/Sema/SemaTemplate.cpp

@@ -158,7 +158,7 @@ bool Sema::hasAnyAcceptableTemplateNames(LookupResult &R,
 TemplateNameKind Sema::isTemplateName(Scope *S,
                                       CXXScopeSpec &SS,
                                       bool hasTemplateKeyword,
-                                      UnqualifiedId &Name,
+                                      const UnqualifiedId &Name,
                                       ParsedType ObjectTypePtr,
                                       bool EnteringContext,
                                       TemplateTy &TemplateResult,
@@ -4102,7 +4102,7 @@ Sema::BuildQualifiedTemplateIdExpr(CXXScopeSpec &SS,
 TemplateNameKind Sema::ActOnDependentTemplateName(Scope *S,
                                                   CXXScopeSpec &SS,
                                                   SourceLocation TemplateKWLoc,
-                                                  UnqualifiedId &Name,
+                                                  const UnqualifiedId &Name,
                                                   ParsedType ObjectType,
                                                   bool EnteringContext,
                                                   TemplateTy &Result,

clang/test/CXX/drs/dr1xx.cpp

@@ -67,7 +67,10 @@ namespace dr108 { // dr108: yes
 namespace dr109 { // dr109: yes
   struct A { template<typename T> void f(T); };
   template<typename T> struct B : T {
-    using T::template f; // expected-error {{using declaration cannot refer to a template}}
+    using T::template f; // expected-error {{'template' keyword not permitted here}}
+    using T::template f<int>; // expected-error {{'template' keyword not permitted here}} expected-error {{using declaration cannot refer to a template specialization}}
+    // FIXME: We shouldn't suggest using the 'template' keyword in a location where it's not valid.
+    using T::f<int>; // expected-error {{use 'template' keyword}} expected-error {{using declaration cannot refer to a template specialization}}
     void g() { this->f<int>(123); } // expected-error {{use 'template'}}
   };
 }

clang/test/CXX/drs/dr4xx.cpp

@@ -318,8 +318,8 @@ namespace dr420 { // dr420: yes
     q->~id<int>();
     p->id<int>::~id<int>();
     q->id<int>::~id<int>();
-    p->template id<int>::~id<int>(); // expected-error {{expected unqualified-id}}
+    p->template id<int>::~id<int>(); // expected-error {{'template' keyword not permitted here}} expected-error {{base type 'int' is not a struct}}
-    q->template id<int>::~id<int>(); // expected-error {{expected unqualified-id}}
+    q->template id<int>::~id<int>(); // expected-error {{'template' keyword not permitted here}} expected-error {{base type 'int' is not a struct}}
     p->A::template id<int>::~id<int>();
     q->A::template id<int>::~id<int>();
   }

clang/test/CXX/temp/temp.res/p3.cpp

@@ -34,5 +34,5 @@ template<typename T> template<typename U> struct A<T>::B {
   // a type, and then complain about the rest of the tokens, and then complain
   // that we didn't get a function declaration.
   friend A<U>::C<T> f7(); // expected-error {{use 'template' keyword to treat 'C' as a dependent template name}} expected-error 3{{}}
-  friend A<U>::template C<T> f8(); // expected-error 3{{}}
+  friend A<U>::template C<T> f8(); // expected-error 4{{}}
 };

clang/test/Parser/cxx-decl.cpp

@@ -237,10 +237,11 @@ namespace PR5066 {
 namespace PR17255 {
 void foo() {
   typename A::template B<>; // expected-error {{use of undeclared identifier 'A'}}
+  // expected-error@-1 {{'template' keyword not permitted here}}
 #if __cplusplus <= 199711L
-  // expected-error@-2 {{'template' keyword outside of a template}}
+  // expected-error@-3 {{'template' keyword outside of a template}}
 #endif
-  // expected-error@-4 {{expected a qualified name after 'typename'}}
+  // expected-error@-5 {{expected a qualified name after 'typename'}}
 }
 }
 

clang/test/SemaCXX/cxx1y-variable-templates_in_class.cpp

@@ -382,16 +382,16 @@ int main() {
 
 namespace dependent_static_var_template {
   struct A {
-    template<int = 0> static int n; // expected-note {{here}}
+    template<int = 0> static int n; // expected-note 2{{here}}
   };
-  int &r = A::template n; // FIXME: ill-formed
+  int &r = A::template n; // expected-error {{use of variable template 'n' requires template arguments}}
 
   template<typename T>
   int &f() { return T::template n; } // expected-error {{use of variable template 'n' requires template arguments}}
   int &s = f<A>(); // expected-note {{instantiation of}}
 
   namespace B {
-    template<int = 0> static int n;
+    template<int = 0> static int n; // expected-note {{here}}
   }
-  int &t = B::template n; // FIXME: ill-formed
+  int &t = B::template n; // expected-error {{use of variable template 'n' requires template arguments}}
 }

clang/test/SemaTemplate/template-id-expr.cpp

@@ -85,6 +85,52 @@ struct Y0 {
   }
 };
 
+template<typename U> void Y0
+  ::template // expected-error {{expected unqualified-id}}
+    f1(U) {}
+
+// FIXME: error recovery is awful without this.
+    ;
+
+template<typename T>
+struct Y1 {
+  template<typename U>
+  void f1(U);
+
+  template<typename U>
+  static void f2(U);
+
+  void f3(int);
+
+  static int f4(int);
+  template<typename U>
+  static void f4(U);
+
+  template<typename U>
+  void f() {
+    Y1::template f1<U>(0);
+    Y1::template f1(0);
+    this->template f1(0);
+
+    Y1::template f2<U>(0);
+    Y1::template f2(0);
+
+    Y1::template f3(0); // expected-error {{'f3' following the 'template' keyword does not refer to a template}}
+    Y1::template f3(); // expected-error {{'f3' following the 'template' keyword does not refer to a template}}
+
+    int x;
+    x = Y1::f4(0);
+    x = Y1::f4<int>(0); // expected-error {{assigning to 'int' from incompatible type 'void'}}
+    x = Y1::template f4(0); // expected-error {{assigning to 'int' from incompatible type 'void'}}
+
+    x = this->f4(0);
+    x = this->f4<int>(0); // expected-error {{assigning to 'int' from incompatible type 'void'}}
+    x = this->template f4(0); // expected-error {{assigning to 'int' from incompatible type 'void'}}
+  }
+};
+
+void use_Y1(Y1<int> y1) { y1.f<int>(); } // expected-note {{in instantiation of}}
+
 struct A {
   template<int I>
   struct B {