http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57746
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Andy Lutomirski from comment #4)
> Daniel, I'm unconvinced that your interpretation is the intended one.
The definition is also a declaration, see [basic.def] p2, as Daniel pointed
out.
> [temp.explicit].4 says "A declaration of [list including member function]
> ... A definition of [list not including member function]". If definitions
> were intended to be declarations in this context, then the second part would
> be redundant, I think.
That doesn't follow at all. The second part describes different types of
entities that have different requirements.
For the first list an explicit instantiation must follow a declaration (and a
definition also counts as a declaration) but for the second list an explicit
instantiation must follow a definition, a declaration is not sufficient.
> Regardless, the interesting case is:
>
> template<typename T>
> struct X
> {
> static int val;
> static void func();
> };
>
> // optionally: extern template struct X<int>;
>
> void something()
> {
> X<int>::func();
> }
>
> in one file and
>
> struct X
> {
> static int val;
> static void func();
> };
>
> template<> void X<int>::func() {}
>
> in another. I don't think this is an odr violation, since there is only one
> definition of anything that could be confused with X<int>::func. g++ will
> happily compile and link it (without the extern template bit) and it will
> work. It is supposed to? Could a conforming compiler mangle the
> specialized version of func differently?
Isn't this ill-formed, with no diagnostic required, by both [temp] p6 and
[temp.expl.spec] p6?
