A namespace-member-declaration is either a namespace-declaration (16.2) or a type-declaration (16.5).

namespace-member-declaration

namespace-member-declaration

namespace-member-declarations namespace-member-declaration

namespace-member-declaration

namespace-declaration

type-declaration

A compilation unit or a namespace body can contain namespace-member-declarations, and such declarations contribute new members to the underlying declaration space of the containing compilation unit or namespace body.