A namespace-member-declaration is either a namespace-declaration (16.2) or a type-declaration (16.5). namespace-member-declarations : namespace-member-declarationnamespace-member-declarationsnamespace-member-declarationnamespace-member-declaration : namespace-declarationtype-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.