https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84221
--- Comment #5 from Martin Sebor <msebor at gcc dot gnu.org> --- As per subsequent discussion (https://gcc.gnu.org/ml/gcc-patches/2018-04/msg00203.html and follow-ups), the warning in the original test case is expected and desirable. The patch in r259098 doesn't change that but has GCC issue a warning for uses of the primary template.
