[Bug c++/59056] ambiguous call to function template overloads not diagnosed

["richard-gccbugzilla at metafoo dot co.uk" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59056

--- Comment #8 from Richard Smith <richard-gccbugzilla at metafoo dot co.uk> ---
(In reply to Walter Mascarenhas from comment #7)
> In itself, Richard's paragraph "Morally, the function should ambiguous... "
> implies that the code below is ambiguous. However, it
> compiles just fine with gcc 4.8.1, because gcc also takes into
> account the information  that check< Foo<int> >() is false
> in order to discard the specialization with the enable_if. In
> other words, the X in check<X> is not completely arbitrary,
> it my be related to Foo<T>.

GCC can't instantiate check<Ty> with a dependent type Ty, because that's not a
meaningful thing to do. And it's not allowed to use Foo<int>, because partial
ordering of templates does not depend on the actual deduced arguments for the
template specialization (it orders the templates themselves, not their
specializations). Also, the only available definition of check always returns
true. So I really don't see how that could be the case.