https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69701
Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords|accepts-invalid | --- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> --- So I think clang and MSVC have a bug in this area too. See basic.lookup.classref/7 : If the id-expression is a conversion-function-id, its conversion-type-id is first looked up in the class of the object expression (11.8) and the name, if found, is used. Otherwise it is looked up in the context of the entire postfix-expression. In each of these lookups, only names that denote types or templates whose specializations are types are considered. [Example: struct A { }; namespace N { struct A { void g() { } template <class T> operator T(); }; } int main() { N::A a; a.operator A(); // calls N::A::operator N::A } — end example] If we take the example, clang and MSVC calls N::A::operator ::A and not what the standard says. GCC I think is still wrong in the original testcase I think because B::A does not represent a type . In my example in comment #4, GCC and ICC does the correct thing and selects the correct type.