Since we don't unique specializations for concepts, we can just instantiate
them with the sugared template arguments, at negligible cost.
If we don't track their specializations, we can't resugar them later
anyway, and that would be more expensive than just instantiating them
sugared in the first place since it would require an additional pass.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D136566
Since we don't unique specializations for concepts, we can just instantiate
them with the sugared template arguments, at negligible cost.
If we don't track their specializations, we can't resugar them later
anyway, and that would be more expensive than just instantiating them
sugared in the first place since it would require an additional pass.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D136566
requires-expression
As reported: https://github.com/llvm/llvm-project/issues/57487
We properly treated a failed instantiation of a concept as a
unsatisified constraint, however, we need to do this at the 'requires
clause' level as well. This ensures that the parameters on a requires
clause that fail instantiation will cause a satisfaction failure.
This patch implements this by running requires parameter clause
instantiation under a SFINAE trap, then stores any such failure as a
requirement failure, so it can be diagnosed later.
Given a dependent `T` (maybe an undeduced `auto`),
Before:
new T(z) --> new T((z)) # changes meaning with more args
new T{z} --> new T{z}
T(z) --> T(z)
T{z} --> T({z}) # forbidden if T is auto
After:
new T(z) --> new T(z)
new T{z} --> new T{z}
T(z) --> T(z)
T{z} --> T{z}
Depends on D113393
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D120608
Now with concepts support merged and mostly complete, we do not need -fconcepts-ts
(which was also misleading as we were not implementing the TS) and can enable
concepts features under C++2a. A warning will be generated if users still attempt
to use -fconcepts-ts.
Implement support for C++2a requires-expressions.
Re-commit after compilation failure on some platforms due to alignment issues with PointerIntPair.
Differential Revision: https://reviews.llvm.org/D50360
