#pragma warn error @interface Object { Class isa; } -(void)dealloc; @end @interface derived : Object @end @implementation Object -(void) dealloc { // this is the root of the hierarchy, so no super to call, thus // must not check for [super dealloc] } @end @implementation derived -(void) dealloc { // as this is a derived class, failure to call [super dealloc] will // result in a memory leak (yes, there could be special allocators // involved, in which case something will be needed to inform the // compiler) } @end void __obj_exec_class (struct obj_module *msg) = #0; id obj_msgSend_super (Super *class, SEL op, ...) = #0; int main () { return 1; // test fails if compile succeeds (with -Werror) }