[libcxx-commits] [libcxx] [libc++] LWG3187: P0591R4 reverted DR 2586 fixes to `scoped_allocator_adaptor::construct()` (PR #152424)

[A. Jiang via libcxx-commits]

frederick-vs-ja wrote:

@philnik777 Split the `polymorphic_allocator` part to #171090.

There seem some difficulties on applying the mechanisms to `scoped_allocator_adaptor` in C++14/17 modes. I'm inclined to use `__transform_tuple_using_allocator_impl` for `scoped_allocator_adaptor` before C++20.

https://github.com/llvm/llvm-project/pull/152424