Program being compiled differently in 3 major C++ compilers. Which one is right?

Question

As an interesting follow-up (not of big practical importance though) to my previous question: Why does C++ allow us to surround the variable name in parentheses when declari

Answer 1

G++ is correct as it gives an error. Because the constructor could not be called directly in such a format without new operator. And although your code calls C::C, it looks like an constructor call. However, according to the C++11 standard 3.4.3.1, this is not a legal function call, or a type name (see Mike Seymour's answer).

Clang is wrong since it even does not call the correct function.

MSVC is something reasonable, but still it does not follow the standard.