anchor.diff:          if (target === null) {
             compiler.internalError("no default constructor available");
           }
  -        sourceElementStack.add(target.implementation);
           inlineSuperOrRedirect(target.implementation,
                                 selector,
                                 const EmptyLink<Node>(),
                                 constructors,
                                 fieldValues);
  -        sourceElementStack.removeLast();
         }
       }
     }
  
positive.code:         typeInfo = pop();
        }
        if (type.element.isTypeVariable()) {
          // TODO(karlklose): We currently answer true to any is check
          // involving a type variable -- both is T and is !T -- until
          // we have a proper implementation of reified generics.
          stack.add(graph.addConstantBool(true, constantSystem));
        } else {
  
negative.code:           FunctionElement target = elements[call];
            Selector selector = elements.getSelector(call);
            Link<Node> arguments = call.arguments;
            inlineSuperOrRedirect(target, selector, arguments, constructors,
                                  fieldValues);
            foundSuperOrRedirect = true;
          } else {
            // A field initializer.
  