https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85282
--- Comment #1 from songyuanyao <songyuanyao at qq dot com> --- The error message for the code (from gcc8.0.1): error: explicit specialization in non-namespace scope
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85282
--- Comment #1 from songyuanyao <songyuanyao at qq dot com> --- The error message for the code (from gcc8.0.1): error: explicit specialization in non-namespace scope