[Bug c++/11859] New: Substitution failure incorrectly reported as error in SFINAE situation.

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11859

           Summary: Substitution failure incorrectly reported as error in
                    SFINAE situation.
           Product: gcc
           Version: 3.4
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: gccbugs at contacts dot eelis dot net
                CC: gcc-bugs at gcc dot gnu dot org

GCC rejects the following legal code:

template <int> struct ItT {};
template <typename T> typename T::x f ();
template <typename T> void g (ItT<sizeof(f<T>(0))> *);
template <typename> void g (...);
void h () { g<int>(0); }

During the consideration of the first g() for the call in h(), the failure to
resolve T::x should not be considered an error and the second g() should be
chosen. GCC however reports:

t.cpp:5: error: no matching function for call to `f(int)'

Comeau (4.3.3 beta) compiles the code without problems.

I'm using GCC version 3.4 20030723.

Note: I'm not 100% sure GCC is wrong here, this is quite complex since this
involves a template function lookup during another template function lookup, and
Comeau might be wrong after all.