9 Commits

Author SHA1 Message Date
Arthur Eubanks
af0dbaaa38 Revert "Following up on PR48517, fix handling of template arguments that refer"
This reverts commit 8c1f2d15b826591cdf6bd6b468b8a7d23377b29e.

This is part of 5 commits being reverted due to https://crbug.com/1161059. See bug for repro.
2020-12-22 10:18:08 -08:00
Richard Smith
8c1f2d15b8 Following up on PR48517, fix handling of template arguments that refer
to dependent declarations.

Treat an id-expression that names a local variable in a templated
function as being instantiation-dependent.

This addresses a language defect whereby a reference to a dependent
declaration can be formed without any construct being value-dependent.
Fixing that through value-dependence turns out to be problematic, so
instead this patch takes the approach (proposed on the core reflector)
of allowing the use of pointers or references to (but not values of)
dependent declarations inside value-dependent expressions, and instead
treating template arguments as dependent if they evaluate to a constant
involving such dependent declarations.

This ends up affecting a bunch of OpenMP tests, due to OpenMP
imprecisely handling instantiation-dependent constructs, bailing out
early instead of processing dependent constructs to the extent possible
when handling the template.
2020-12-17 23:54:37 -08:00
Benjamin Kramer
c41e096bda Revert "[Sema] Reword warning for constant captures that are not required"
This reverts commit r337152. This applies to non-constants too. The real
explanation is that the capture is not ODR-used, but putting that into
the warning message seems ... worse.

llvm-svn: 337278
2018-07-17 13:17:01 +00:00
Benjamin Kramer
c8c90e5b40 [Sema] Reword warning for constant captures that are not required
This is one of the darker corners of C++, make it clear that this is
about constants and rephrase it a bit.

Before: lambda capture 'i' is not required to be captured for this use
After:  lambda capture of constant 'i' is not required for this use
llvm-svn: 337152
2018-07-16 09:52:02 +00:00
Malcolm Parsons
d900a0c4e2 [Sema] Fix crash in unused-lambda-capture warning for VLAs
Summary:
Clang was crashing when diagnosing an unused-lambda-capture for a VLA because
From.getVariable() is null for the capture of a VLA bound.
Warning about the VLA bound capture is not helpful, so only warn for the VLA
itself.

Fixes: PR35555

Reviewers: aaron.ballman, dim, rsmith

Reviewed By: aaron.ballman, dim

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D41016

llvm-svn: 320396
2017-12-11 18:00:36 +00:00
Yi Kong
7db514064a Fix spurious Wunused-lambda-capture warning
Summary:
Clang emits unused-lambda-capture warning for captures in generic lambdas even though they are actually used.

Fixes PR31815.

Reviewers: malcolm.parsons, aaron.ballman, rsmith

Reviewed By: malcolm.parsons

Subscribers: ahatanak, cfe-commits

Differential Revision: https://reviews.llvm.org/D33526

llvm-svn: 305315
2017-06-13 18:38:31 +00:00
Malcolm Parsons
ded2306208 [Sema] Improve side effect checking for unused-lambda-capture warning
Summary:
Don't warn about unused lambda captures that involve copying a
value of a type that cannot be trivially copied and destroyed.

Fixes PR31977

Reviewers: rsmith, aaron.ballman

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D30327

llvm-svn: 296602
2017-03-01 10:23:38 +00:00
Malcolm Parsons
bece0cd512 [Sema] Reword unused lambda capture warning
Summary:
The warning doesn't know why the variable was looked up but not
odr-used, so reword it to not claim that it was used in an unevaluated
context.

Reviewers: aaron.ballman

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D28902

llvm-svn: 292498
2017-01-19 17:19:22 +00:00
Malcolm Parsons
87a036259b [Sema] Add warning for unused lambda captures
Summary:
Warn when a lambda explicitly captures something that is not used in its body.

The warning is part of -Wunused and can be enabled with -Wunused-lambda-capture.

Reviewers: rsmith, arphaman, jbcoe, aaron.ballman

Subscribers: Quuxplusone, arphaman, cfe-commits

Differential Revision: https://reviews.llvm.org/D28467

llvm-svn: 291905
2017-01-13 15:01:06 +00:00