https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107408
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Clang prints three errors. The first one hints at the real problem, but the
next two are bogus:
t.C:6:37: error: 'S' is not a class, namespace, or enumeration
template<class T> template<class U> S::S(U) { }
^
t.C:1:26: note: 'S' declared here
template<class T> struct S
^
t.C:6:1: error: extraneous template parameter list in template specialization
or out-of-line template definition
template<class T> template<class U> S::S(U) { }
^~~~~~~~~~~~~~~~~
t.C:6:48: error: expected ';' at end of declaration
template<class T> template<class U> S::S(U) { }
^
;
3 errors generated.
