https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61659
--- Comment #26 from Markus Trippelsdorf <trippels at gcc dot gnu.org> --- ยง14.7.3/12 says: An explicit specialization of a function template is inline only if it is declared with the inline specifier or defined as deleted, and independently of whether its function template is inline.
