[Bug c++/34756] New: [4.3 regression] ICE with broken specialization of variadic template

[reichelt at gcc dot gnu dot org]

The following invalid code snippet triggers an ICE on mainline:

================================================================
template<typename...> class A {};

template<int> class A<> {};

template<typename T, typename...U> struct A<T,U...> : A<U...>
{
  A() {}
};

A<int> a;
================================================================

bug.cc:3: error: template parameters not used in partial specialization:
bug.cc:3: error:         '<anonymous>'
bug.cc: In constructor 'A<T, U ...>::A() [with T = int, U = ]':
bug.cc:10:   instantiated from here
bug.cc:7: internal compiler error: in build_simple_base_path, at cp/class.c:489
Please submit a full bug report, [etc.]


-- 
           Summary: [4.3 regression] ICE with broken specialization of
                    variadic template
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Keywords: ice-on-invalid-code, error-recovery, monitored
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: reichelt at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34756