fheaderp = (struct simple_fun *) native_pointer(fheaderl);
gc_assert(widetag_of(fheaderp->header) == SIMPLE_FUN_HEADER_WIDETAG);
fheaderp = (struct simple_fun *) native_pointer(fheaderl);
gc_assert(widetag_of(fheaderp->header) == SIMPLE_FUN_HEADER_WIDETAG);