Members of an inline namespace can be used in most respects as though they were members
of the innermost enclosing namespace
. Furthermore, each
member of the inline namespace can subsequently be partially
specialized (
[temp.spec.partial]), explicitly
instantiated (
[temp.explicit]), or explicitly specialized (
[temp.expl.spec]) as
though it were a member of the enclosing namespace
. Finally, looking up a name in the
enclosing namespace via explicit qualification (
[namespace.qual]) will include
members of the inline namespace even if
there are declarations of that name in the enclosing namespace
.