[all-commits] [llvm/llvm-project] abf4a8: [Clang] Improve diagnostics when using a concept a...

[cor3ntin via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: abf4a8cb15d4faf04ee0da14e37d7349d3bde9a1
      https://github.com/llvm/llvm-project/commit/abf4a8cb15d4faf04ee0da14e37d7349d3bde9a1
  Author: Corentin Jabot <corentinjabot at gmail.com>
  Date:   2023-03-30 (Thu, 30 Mar 2023)

  Changed paths:
    M clang/docs/ReleaseNotes.rst
    M clang/lib/Parse/ParseDecl.cpp
    M clang/lib/Parse/Parser.cpp
    A clang/test/Parser/cxx-template-template-recovery.cpp

  Log Message:
  -----------
  [Clang] Improve diagnostics when using a concept as template argument

When using the name of a template variable or concept in places
where an expression was expected, Clang would drop the cxxscope token
preceeding it, if any.

This leads to subpar diagnostics - complaining about the
identifier being undeclared as clang would not know to look into a
non-global scope.

We make sure the scope is preserved.

When encountering `ns::Concept foo x;`, Clang would also fail
to provide the same quality as it does at global scope.

Reviewed By: aaron.ballman, erichkeane

Differential Revision: https://reviews.llvm.org/D146719