[PATCH] D126969: Allow use of an elaborated type specifier in a _Generic association in C++

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman created this revision.
aaron.ballman added reviewers: erichkeane, jyknight, clang-language-wg.
Herald added a project: All.
aaron.ballman requested review of this revision.
Herald added a project: clang.

Currently, Clang accepts this code in C mode (where the tag is required to be used) but rejects it in C++ mode thinking that the association is defining a new type.

  void foo(void) {
    struct S { int a; };
    _Generic(something, struct S : 1);
  }

Clang thinks this in C++ because it sees `struct S :` when parsing the class specifier and decides that must be a type definition (because the colon signifies the presence of a base class type). This patch adds a new declarator context to represent a `_Generic` association so that we can distinguish these situations properly.

Fixes #55562


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D126969

Files:
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Parse/Parser.h
  clang/include/clang/Sema/DeclSpec.h
  clang/lib/Parse/ParseDecl.cpp
  clang/lib/Parse/ParseDeclCXX.cpp
  clang/lib/Parse/ParseExpr.cpp
  clang/lib/Sema/SemaType.cpp
  clang/test/Sema/generic-selection.c
  clang/test/SemaCXX/generic-selection.cpp

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