[Bug c++/53162] unexpanded parameter packs not diagnosed in alias template used in default argument

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53162

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-04-30 08:12:44 UTC ---
(In reply to comment #0)
> The declaration of f1 is rejected but with an unhelpful diagnostic, if the
                     ^^
That should say:     f2

I believe the errors should be given when the constructor templates are
defined, rather than at instantiation, because "An appearance of a name of a
parameter pack that is not expanded is ill-formed." (14.5.3 [temp.variadic] p5)