http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48934
--- Comment #5 from froydnj at codesourcery dot com <froydnj at codesourcery dot com> 2011-05-09 15:38:14 UTC --- Thanks for checking. I'll attempt to the make the patch do something intelligent on at least the original testcase and this: > template<typename T> struct S1 { typedef char type; }; > > template<typename T> > typename S1<T>::type > foo(typename S1<T>::typo) > { return t; } > > char c = foo<int>(1); > > Here the return type is valid, but the parameter is not ("typo" vs "type"). > Ideally the diagnostic would indicate that, which would help when the template > arguments are substituted in more than one place. Thanks for the additional testcases! > I realise that might be very difficult to do and that as a library implementor > my wishlist may not be typical of most users. Simply saying something like > "substitution failed" would already be a nice improvement. "substitution failed" will probably be the default message if we can't provided anything more intelligent.