This patch backports a one-liner `std::to_underlying` that came with C++23. This is useful for refactoring unscoped enums into scoped enums, because the latter are not implicitly convertible to integer types.
I followed libc++ implementation, but I consider their testing too heavy for us, so I wrote a simpler set of tests.
value() has undesired exception checking semantics and calls
__throw_bad_optional_access in libc++. Moreover, the API is unavailable without
_LIBCPP_NO_EXCEPTIONS on older Mach-O platforms (see
_LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS).
This fixes check-llvm.
llvm::Optional<T> has transform, which is equivalent to
std::optional<T>::transform. The problem is that
std::optional<T>::transform won't be available until C++23, implying
that we probably cannot use it in our codebase untli 2028 or so. We
certainly don't want to keep llvm::Optional just for transform.
This patch adds llvm::transformOptional to STLForwardCompat.h so that
we can use transform during the migration to std::optional and beyond.
I've shamelessly borrowed the implementation and test from
llvm/include/llvm/ADT/Optional.h and
llvm/unittests/ADT/OptionalTest.cpp respectively.
This is part of an effort to migrate from llvm::Optional to
std::optional:
https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
Differential Revision: https://reviews.llvm.org/D139779
As a follow-up of e8578968f684997840f680ed62bff5cad0accc13 which replaced the
callers to use the C++17 equivalents, remove the equivalents from
`STLForwardCompat.h` entirely and their corresponding tests.
Differential Revision: https://reviews.llvm.org/D131769
Move some types in STLExtras.h which are named and behave identically to
STL types from future standards into a dedicated header. This keeps them
organized (they are not "extras" in the same sense as most types in
STLExtras.h are) and fixes circular dependencies in future patches.
Reviewed By: dblaikie
Differential Revision: https://reviews.llvm.org/D100668
