[all-commits] [llvm/llvm-project] aafad2: [Clang] Warn on deprecated specializations used in...

[cor3ntin via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: aafad2d214246bae4d53ce3178b11486ebc83890
      https://github.com/llvm/llvm-project/commit/aafad2d214246bae4d53ce3178b11486ebc83890
  Author: cor3ntin <corentinjabot at gmail.com>
  Date:   2023-11-17 (Fri, 17 Nov 2023)

  Changed paths:
    M clang/docs/ReleaseNotes.rst
    M clang/include/clang/Sema/Sema.h
    M clang/lib/Sema/SemaAvailability.cpp
    M clang/lib/Sema/SemaTemplate.cpp
    A clang/test/SemaCXX/warn-deprecated-specializations-in-system-headers.cpp

  Log Message:
  -----------
  [Clang] Warn on deprecated specializations used in system headers. (#70353)

When the top of the instantiation stack is in user code.

The goal of this PR is to allow deprecation of some char_traits
specializations in libc++ as done in https://reviews.llvm.org/D157058
which was later reverted by
https://github.com/llvm/llvm-project/pull/66153#issuecomment-1719578384
as Clang never emitted the libc++ warnings.

Because Clang likes to eagerly instantiate, we can look for the location
of the top of the instantiation stack, and emit a warning if that
location is in user code.

The warning emission is forced by temporarily instructing the diag
engine not to silence warning in system headers.