Specifically, the following features are not included in this commit:
- any sort of capturing within generic lambdas
- nested lambdas
- conversion operator for captureless lambdas
- ensuring all visitors are generic lambda aware
As an example of what compiles:
template <class F1, class F2>
struct overload : F1, F2 {
using F1::operator();
using F2::operator();
overload(F1 f1, F2 f2) : F1(f1), F2(f2) { }
};
auto Recursive = [](auto Self, auto h, auto ... rest) {
return 1 + Self(Self, rest...);
};
auto Base = [](auto Self, auto h) {
return 1;
};
overload<decltype(Base), decltype(Recursive)> O(Base, Recursive);
int num_params = O(O, 5, 3, "abc", 3.14, 'a');
Please see attached tests for more examples.
Some implementation notes:
- Add a new Declarator context => LambdaExprParameterContext to
clang::Declarator to allow the use of 'auto' in declaring generic
lambda parameters
- Augment AutoType's constructor (similar to how variadic
template-type-parameters ala TemplateTypeParmDecl are implemented) to
accept an IsParameterPack to encode a generic lambda parameter pack.
- Add various helpers to CXXRecordDecl to facilitate identifying
and querying a closure class
- LambdaScopeInfo (which maintains the current lambda's Sema state)
was augmented to house the current depth of the template being
parsed (id est the Parser calls Sema::RecordParsingTemplateParameterDepth)
so that Sema::ActOnLambdaAutoParameter may use it to create the
appropriate list of corresponding TemplateTypeParmDecl for each
auto parameter identified within the generic lambda (also stored
within the current LambdaScopeInfo). Additionally,
a TemplateParameterList data-member was added to hold the invented
TemplateParameterList AST node which will be much more useful
once we teach TreeTransform how to transform generic lambdas.
- SemaLambda.h was added to hold some common lambda utility
functions (this file is likely to grow ...)
- Teach Sema::ActOnStartOfFunctionDef to check whether it
is being called to instantiate a generic lambda's call
operator, and if so, push an appropriately prepared
LambdaScopeInfo object on the stack.
- Teach Sema::ActOnStartOfLambdaDefinition to set the
return type of a lambda without a trailing return type
to 'auto' in C++1y mode, and teach the return type
deduction machinery in SemaStmt.cpp to process either
C++11 and C++14 lambda's correctly depending on the flag.
- various tests were added - but much more will be needed.
A greatful thanks to all reviewers including Eli Friedman,
James Dennett and the ever illuminating Richard Smith. And
yet I am certain that I have allowed unidentified bugs to creep in;
bugs, that I will do my best to slay, once identified!
Thanks!
llvm-svn: 188977
referenced as a member of the current instantiation. In that case, deduce the
type of the function to a dependent type rather than exposing an undeduced auto
type to the rest of the current instantiation.
The standard doesn't really say that the type is dependent in this case; I'll
bring this up with CWG.
llvm-svn: 188410
This patch essentially removes all the FIXMEs following calls to DeduceTemplateArguments() that want to keep track of deduction failure info.
llvm-svn: 186730
substitution failed, report that as a substitution failure rather than
pretending that there was no default argument.
The test cases in PR15673 have exposed some pre-existing poor diagnostics here.
llvm-svn: 185604
are now two distinct canonical 'AutoType's: one is the undeduced 'auto'
placeholder type, and the other is a deduced-but-dependent type. All
deduced-to-a-non-dependent-type cases are still non-canonical.
llvm-svn: 180789
This was causing correctness issues for ARC and the static analyzer when a
function template has "consumed" Objective-C object parameters (i.e.
parameters that will be released by the function before returning).
The fix is threefold:
(1) Actually copy over the attributes from old ParmVarDecls to new ones.
(2) Have Sema::BuildFunctionType only work for building FunctionProtoTypes,
which it was doing anyway. This allows us to pass an ExtProtoInfo
instead of a plain ExtInfo and several flags.
(3) Drop param attributes as part of StripImplicitInstantiation, which is
used when an implicit instantiation is followed by an explicit one.
<rdar://problem/12685622>
llvm-svn: 176728
have a direct mismatch between some component of the template and some
component of the argument. The diagnostic now says what the mismatch was, but
doesn't yet say which part of the template doesn't match.
llvm-svn: 174039
partially-substituted parameter pack in a template, forget about the
partially-substituted parameter pack: it is now completed. Fixes
<rdar://problem/12176336>.
llvm-svn: 172859
Don't require that, during template deduction, a template specialization type
as a function parameter has at least as many template arguments as one used in
a function argument (not even if the argument has been resolved to an exact
type); the additional parameters might be provided by default template
arguments in the template. We don't need this check, since we now implement
[temp.deduct.call]p4 with an additional check after deduction.
llvm-svn: 169475
uncovered.
This required manually correcting all of the incorrect main-module
headers I could find, and running the new llvm/utils/sort_includes.py
script over the files.
I also manually added quite a few missing headers that were uncovered by
shuffling the order or moving headers up to be main-module-headers.
llvm-svn: 169237
* getMostSpecialized()
/// \param Index if non-NULL and the result of this function is non-nULL,
/// receives the index corresponding to the resulting function template
/// specialization.
* DeduceTemplateArguments()
/// \param Name the name of the function being called. This is only significant
/// when the function template is a conversion function template, in which
/// case this routine will also perform template argument deduction based on
/// the function to which
llvm-svn: 167909
the base class. If the base class deduction succeeds, use those results. If
it fails, keep using the results from the derived class template deduction.
This prevents an assertion later where the type of deduction failure doesn't
match up with the template deduction info.
llvm-svn: 167550
enough information so we can mangle them correctly in cases involving
dependent parameter types. (This specifically impacts cases involving
null pointers and cases involving parameters of reference type.)
Fix the mangler to use this information instead of trying to scavenge
it out of the parameter declaration.
<rdar://problem/12296776>.
llvm-svn: 164656
unexpanded parameter pack is a pack expansion. Thus, as with a non-type template
parameter which is a pack expansion, it needs to be expanded early into a fixed
list of template parameters.
Since the expanded list of template parameters is not itself a parameter pack,
it is permitted to appear before the end of the template parameter list, so also
remove that restriction (for both template template parameter pack expansions and
non-type template parameter pack expansions).
llvm-svn: 163369
[temp.deduct.call]p4 under Objective-C++ ARC, make sure to adjust the
qualifiers to introduce the implicit strong lifetime when
needed. Fixes <rdar://problem/11825671>.
llvm-svn: 160412
as an array of its base class TemplateArgument. Switch the const
TemplateArgument* parameters of InstantiatingTemplate's constructors to
ArrayRef<TemplateArgument> to prevent this from happening again in the future.
llvm-svn: 160245
* When substituting a reference to a non-type template parameter pack where the
corresponding argument is a pack expansion, transform into an expression
which contains an unexpanded parameter pack rather than into an expression
which contains a pack expansion. This causes the SubstNonTypeTemplateParmExpr
to be inside the PackExpansionExpr, rather than outside, so the expression
still looks like a pack expansion and can be deduced.
* Teach MarkUsedTemplateParameters that we can deduce a reference to a template
parameter if it's wrapped in a SubstNonTypeTemplateParmExpr (such nodes are
added during alias template substitution).
llvm-svn: 159922
expression, skip over any SubstNonTypeTemplateParmExprs which alias templates
may have inserted before checking for a DeclRefExpr referring to a non-type
template parameter declaration.
llvm-svn: 159909
Robert Wilhelm