[clang] Correctly implement CWG 2672 (#75001)

[Sema] Lambdas are not part of immediate context for deduction

This commit implements [temp.deduct]p9.
Test updates include:
- New notes in `cxx1y-init-captures.cpp`, `lambda-expressions.cpp`
and

[Sema] Lambdas are not part of immediate context for deduction

This commit implements [temp.deduct]p9.
Test updates include:
- New notes in `cxx1y-init-captures.cpp`, `lambda-expressions.cpp`
and 'warn-unused-lambda-capture.cpp'.
This seems to be caused by diagnosing errors earlier (during
deduction) that were previously surfaced later (during
instantiation).
- New error `lambda-unevaluated.cpp` is in line with [temp.deduct]p9.

Reviewed By: erichkeane, #clang-language-wg

Differential Revision: https://reviews.llvm.org/D148802

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[clang] Correct handling of lambdas in lambda default arguments in dependent contexts.

Previously, a lambda expression in a dependent context with a default argument
containing an immediately invoke

[clang] Correct handling of lambdas in lambda default arguments in dependent contexts.

Previously, a lambda expression in a dependent context with a default argument
containing an immediately invoked lambda expression would produce a closure
class object that, if invoked such that the default argument was used, resulted
in a compiler crash or one of the following assertion failures during code
generation. The failures occurred regardless of whether the lambda expressions
were dependent.

clang/lib/CodeGen/CGCall.cpp:
Assertion `(isGenericMethod || Ty->isVariablyModifiedType() || Ty.getNonReferenceType()->isObjCRetainableType() || getContext() .getCanonicalType(Ty.getNonReferenceType()) .getTypePtr() == getContext().getCanonicalType((*Arg)->getType()).getTypePtr()) && "type mismatch in call argument!"' failed.

clang/lib/AST/Decl.cpp:
Assertion `!Init->isValueDependent()' failed.

Default arguments in declarations in local context are instantiated along with
their enclosing function or variable template (since such declarations can't
be explicitly specialized). Previously, such instantiations were performed at
the same time that their associated parameters were instantiated. However, that
approach fails in cases like the following in which the context for the inner
lambda is the outer lambda, but construction of the outer lambda is dependent
on the parameters of the inner lambda. This change resolves this dependency by
delyaing instantiation of default arguments in local contexts until after
construction of the enclosing context.
template <typename T>
auto f() {
return [](T = []{ return T{}; }()) { return 0; };
}

Refactoring included with this change results in the same code now being used
to instantiate default arguments that appear in local context and those that
are only instantiated when used at a call site; previously, such code was
duplicated and out of sync.

Fixes https://github.com/llvm/llvm-project/issues/49178

Reviewed By: erichkeane

Differential Revision: https://reviews.llvm.org/D133500

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Fix a pair of tests that would fail on a win32 box

The tests don't specify a triple in some cases, since they shouldn't be
necessary, so I've updated the tests to detect via macro when they are
runn

Fix a pair of tests that would fail on a win32 box

The tests don't specify a triple in some cases, since they shouldn't be
necessary, so I've updated the tests to detect via macro when they are
running on win32 to give the slightly altered diagnostic.

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Update 'note-candiate' functions to skip lambda-conversion-op-overloads

In the wake of https://reviews.llvm.org/D89559, we discovered that a
couple of tests (the ones modified below to have addition

Update 'note-candiate' functions to skip lambda-conversion-op-overloads

In the wake of https://reviews.llvm.org/D89559, we discovered that a
couple of tests (the ones modified below to have additional triple
versions) would fail on Win32, for 1 of two reasons. We seem to not
have a win32 buildbot anymore, so the triple is to make sure this
doesn't get broken in the future.

First, two of the three 'note-candidate' functions weren't appropriately
skipping the remaining conversion functions.

Second, in 1 situation (note surrogate candidates) we actually print the
type of the conversion operator. The two tests that ran into that
needed updating to make sure it printed the proper one in the win32
case.

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Instantiate function declarations in instantiated functions.

If a function declaration is found inside a template function as in:

template<class T> void f() {
void g(int x = T::v) except(

Instantiate function declarations in instantiated functions.

If a function declaration is found inside a template function as in:

template<class T> void f() {
void g(int x = T::v) except(T::w);
}

it must be instantiated along with the enclosing template function,
including default arguments and exception specification.

Together with the patch committed in r240974 this implements DR1484.

Differential Revision: http://reviews.llvm.org/D11194

llvm-svn: 245810

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DR974: Lambdas can have default arguments.

llvm-svn: 179688

Implement C++ core issue 974, which permits default arguments for
lambda expressions. Because these issue was pulled back from Ready
status at the Kona meeting, we still emit an ExtWarn when using
de

Implement C++ core issue 974, which permits default arguments for
lambda expressions. Because these issue was pulled back from Ready
status at the Kona meeting, we still emit an ExtWarn when using
default arguments for lambda expressions.

llvm-svn: 150519

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