ary_ensure_room_for_push  908 array.c            VALUE target_ary = ary_ensure_room_for_push(ary, 1);
ary_ensure_room_for_push  920 array.c            VALUE target_ary = ary_ensure_room_for_push(ary, len);
ary_ensure_room_for_push 1594 array.c        	target_ary = ary_ensure_room_for_push(ary, rlen-len); /* len is 0 or negative */