[Clang] Incorrect "Redeclaration of using-enum declaration"

[kezyr]

This code compiles normaly on gcc, msvc but clangd says Redeclaration of using-enum declaration.

struct A {
  enum class B {BB};
  using enum B;
  struct C {
    using enum B;
  };
};

https://godbolt.org/z/9d48vcrnv

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Miro Rýzek (kezyr)

This code compiles normaly on gcc, msvc but clangd says `Redeclaration of using-enum declaration`. ```c++ struct A { enum class B {BB}; using enum B; struct C { using enum B; }; }; ``` https://godbolt.org/z/9d48vcrnv

[shafik]

Funny enough MSVC reject this, which should be equivalent but clang accepts: https://godbolt.org/z/qh8T9Phj8

struct A {
  enum class B {BB};
  using enum B;
  struct C {
    using B::BB;
  };
};