declare and using enum class and using in one statement

Question

When using scoped enums I stumbled over some syntax which is accepted by Microsoft, but not by clang or gcc:

using enum class Color {
  RED, GREEN, BLUE
};

(https://godbolt.org/z/arPcYME7s)

I think that could be a nice shortcut to save an extra using enum statement.

When looking for some documentation on this I couldn't find any, https://en.cppreference.com/w/cpp/language/enum doesn't mention this syntax, also the Microsoft documentation doesn't know about this.

My question is, is that syntax going to be allowed in some future version of C++, so Microsoft implemented it on purpose, or should this considered as a compiler bug?