https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66879
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Clang compiles it OK, but EDG says:
"a.cc", line 5: error: class "A" cannot be defined in the current scope
class A { void f() {} };
This seems similar to the G++ error, which is due to the name A referring to
::A, which should be defined in the global scope.
I'm not sure whether the definition of Y::A should be an error, or (as Clang
thinks) should declare a new type, which cannot be referred to due to the
ambiguity caused by the using-declaration.
