Fixed weird struct problem from downs, see mini/compile_structs1.d Rewrote DtoIndexStruct/Class , the old implementation were way too complex for what we really need now - since the DotVar changes.

module bug40;

char[] func(void* p)
{
    return null;
}

void main()
{
    char[] function(void*) fp = &func;
    assert(fp(null) is null);
}