[all-commits] [llvm/llvm-project] af9713: Fix a diagnoses-valid in C++20 with variadic macros

[Aaron Ballman via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: af971365a2a8b0d982814c0652bb86844fd19cda
      https://github.com/llvm/llvm-project/commit/af971365a2a8b0d982814c0652bb86844fd19cda
  Author: Aaron Ballman <aaron at aaronballman.com>
  Date:   2021-10-09 (Sat, 09 Oct 2021)

  Changed paths:
    M clang/include/clang/Basic/DiagnosticLexKinds.td
    M clang/lib/Lex/PPMacroExpansion.cpp
    A clang/test/Preprocessor/empty_va_arg.cpp

  Log Message:
  -----------
  Fix a diagnoses-valid in C++20 with variadic macros

C++20 and later allow you to pass no argument for the ... parameter in
a variadic macro, whereas earlier language modes and C disallow it.

We no longer diagnose in C++20 and later modes. This fixes PR51609.