9 Declarations [dcl.dcl]

9.7 Enumerations [enum]

9.7.2 The using enum declaration [enum.udecl]

using-enum-declaration:
	using elaborated-enum-specifier ;

The elaborated-enum-specifier shall not name a dependent type and the type shall have a reachable enum-specifier .

A using-enum-declaration introduces the enumerator names of the named enumeration as if by a using-declaration for each enumerator.

[ Note

A using-enum-declaration in class scope adds the enumerators of the named enumeration as members to the scope.

This means they are accessible for member lookup.

[ Example

enum class fruit { orange, apple };
struct S {
  using enum fruit;             // OK, introduces orange and apple into S
};
void f() {
  S s;
  s.orange;                     // OK, names fruit::orange
  S::orange;                    // OK, names fruit::orange
}

— end example

]

— end note

]

[ Note

Two using-enum-declarations that introduce two enumerators of the same name conflict.

[ Example

enum class fruit { orange, apple };
enum class color { red, orange };
void f() {
  using enum fruit;             // OK
  using enum color;             // error: color::orange and fruit::orange conflict
}

— end example

]

— end note

]