anchor.diff:      var types = pop() as List<TypeAnnotation>;
       // TODO(brianwilkerson) Report diagnostics for any type that's filtered out.
       return types.whereType<NamedType>().toList();
  -  }
  -
  -  void pushForControlFlowInfo(Token? awaitToken, Token forToken,
  -      Token leftParenthesis, ForLoopPartsImpl forLoopParts, Object entry) {
  -    push(
  -      ForElementImpl(
  -        awaitKeyword: awaitToken,
  -        forKeyword: forToken,
  -        leftParenthesis: leftParenthesis,
  -        forLoopParts: forLoopParts,
  -        rightParenthesis: leftParenthesis.endGroup!,
  -        body: entry as CollectionElementImpl,
  -      ),
  -    );
  -  }
  -
  -  void pushIfControlFlowInfo(
  -      Token ifToken,
  -      _ParenthesizedCondition condition,
  -      CollectionElementImpl thenElement,
  -      Token? elseToken,
  -      CollectionElementImpl? elseElement) {
  -    push(
  -      IfElementImpl(
  -        ifKeyword: ifToken,
  -        leftParenthesis: condition.leftParenthesis,
  -        condition: condition.expression,
  -        caseClause: null,
  -        rightParenthesis: condition.rightParenthesis,
  -        thenElement: thenElement,
  -        elseKeyword: elseToken,
  -        elseElement: elseElement,
  -      ),
  -    );
     }
   
     void reportErrorIfNullableType(Token? questionMark) {
  
positive.code:     push(ast.instanceCreationExpression(
          token, constructorName, arguments.argumentList,
          typeArguments: typeArguments));
    }
  
    VariableDeclaration _makeVariableDeclaration({
      required SimpleIdentifierImpl name,
      required Token? equals,
      required ExpressionImpl? initializer,
    }) {
      return VariableDeclarationImpl(
        name2: name.token,
        equals: equals,
        initializer: initializer,
      );
    }
  
    void _reportFeatureNotEnabled({
  
negative.code:   @override
    void endForControlFlow(Token token) {
      debugEvent("endForControlFlow");
      var body = pop() as CollectionElementImpl;
      var forLoopParts = pop() as ForPartsImpl;
      var leftParenthesis = pop() as Token;
      var forToken = pop() as Token;
  
      push(
        ForElementImpl(
          awaitKeyword: null,
          forKeyword: forToken,
          leftParenthesis: leftParenthesis,
          forLoopParts: forLoopParts,
          rightParenthesis: leftParenthesis.endGroup!,
          body: body,
        ),
      );
    }
  
    @override
  