🚀 go-pugleaf

version 2.2.2
configured with mips-dec-ultrix

There is a bug in cc1plus that causes it to segmentation fault when trying
to compile a switch expression that is a class without a conversion to int.
I know that's not legal C++ (apparently it was accepted by cfront1.2), but
it shouldn't crash the compiler.  The problem is in c_expand_start_case in
cp-typeck.c.  There needs to be a test for exp == 0 following the call to
build_type_conversion() (at line 6130).

If that's not good enough, here's a test case:

struct not_an_int {
    char *name;
};

main()
{
    not_an_int a, b, c;

    a.name = "a";
    b.name = "b";

    c = a;
    switch (c) {
	case a:
	    c.next = b;
	    break;
	case b:
	    c.next = a;
	    break;
    }
}