[all-commits] [llvm/llvm-project] 977bdf: Make simple requirements starting with requires il...

[Aaron Ballman via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 977bdf6f44edabb857bdff9ca249aa6eccb98e96
      https://github.com/llvm/llvm-project/commit/977bdf6f44edabb857bdff9ca249aa6eccb98e96
  Author: Corentin Jabot <corentin.jabot at gmail.com>
  Date:   2021-08-03 (Tue, 03 Aug 2021)

  Changed paths:
    M clang/include/clang/Basic/DiagnosticParseKinds.td
    M clang/lib/Parse/ParseExprCXX.cpp
    M clang/test/Parser/cxx2a-concepts-requires-expr.cpp
    M clang/www/cxx_status.html

  Log Message:
  -----------
  Make simple requirements starting with requires ill-formed in in requirement body

This patch implements P2092

Simple requirements in requirement body shall not start with requires.
A warning was already in place so we just turn this warning into an error.

In addition, we add tests to make sure typename is optional in
requirement-parameter-list as per the same paper.