[Bug c++/49663] New: [4.7 Regression] [C++0x] ICE in lookup_base

["redi at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49663

           Summary: [4.7 Regression] [C++0x] ICE in lookup_base
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: redi@gcc.gnu.org
                CC: jason@gcc.gnu.org


struct Nosm 
{
    int m_R;
};

namespace dx {

    struct onc
    {
        typedef void(*Cb)();

        onc(Cb cb);
    };

    struct grac
    {
        template<class Derived> static void once();
    };

    template<class Derived>
        struct tonc : onc
        {
            tonc() : onc(&grac::once<Derived>) {}

            static Derived& get();
        };

    template<class Derived> void grac::once()
    {
        tonc<Derived>::get().h();
    }
}

namespace
{
    template<typename T, int = sizeof(&T::m_R)>
        struct has_R { };

    template<typename T>
        inline void
        setR(T* m, has_R<T>* = 0)
        { }

    inline void setR(...) { }
}

template<typename M>
    struct Qmi
    : dx::tonc<Qmi<M> >
    {
        void h()
        {
            setR(&msg);
        }

        M msg;
    };

Qmi<Nosm> x;


ICE with -std=c++0x, none without, none with 4.6 branch


lookup_base (t=0x0, base=0x7ffff6d9e540, access=0, kind_ptr=0x0)
    at /home/jwakely/src/gcc/gcc/cp/search.c:204
204      if (!TYPE_P (t))
(gdb) p t
$1 = (tree) 0x0
(gdb) bt 2
#0  lookup_base (t=0x0, base=0x7ffff6d9e540, access=0, kind_ptr=0x0)
    at /home/jwakely/src/gcc/gcc/cp/search.c:204
#1  0x0000000000605fc9 in check_accessibility_of_qualified_id (
    decl=0x7ffff6da41c8, object_type=0x0, nested_name_specifier=0x7ffff6d9e540)
    at /home/jwakely/src/gcc/gcc/cp/semantics.c:1695
(More stack frames follow...)