[Bug c++/67074] Name lookup ambiguity between namespace and its alias

[anders.granlund.0 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67074

--- Comment #1 from Anders Granlund <anders.granlund.0 at gmail dot com> ---
I have reported the same bug in clang also:

https://llvm.org/bugs/show_bug.cgi?id=24324

Richard Smith confirmed it and added this additional test case:

And likewise:

  namespace N {}
  namespace N = N;

If a namespace alias really just binds a name to an existing namespace, the
above should be valid, because all declarations of name N in the TU refer to
the same entity.