anchor.diff:  
     @override
     void visitIsExpression(IsExpression node) {
  -    safelyVisitNode(node.expression);
  +    _visitNode(node.expression);
       if (node.notOperator == null) {
  -      sink.write(" is ");
  +      sink.write(' is ');
       } else {
  -      sink.write(" is! ");
  -    }
  -    safelyVisitNode(node.type);
  +      sink.write(' is! ');
  +    }
  +    _visitNode(node.type);
     }
   
     @override
     void visitLabel(Label node) {
  -    safelyVisitNode(node.label);
  -    sink.write(":");
  +    _visitNode(node.label);
  +    sink.write(':');
     }
   
     @override
     void visitLabeledStatement(LabeledStatement node) {
  -    safelyVisitNodeListWithSeparatorAndSuffix(node.labels, " ", " ");
  -    safelyVisitNode(node.statement);
  +    _visitNodeList(node.labels, separator: ' ', suffix: ' ');
  +    _visitNode(node.statement);
     }
   
     @override
     void visitLibraryDirective(LibraryDirective node) {
  -    safelyVisitNodeListWithSeparatorAndSuffix(node.metadata, " ", " ");
  -    sink.write("library ");
  -    safelyVisitNode(node.name);
  +    _visitNodeList(node.metadata, separator: ' ', suffix: ' ');
  +    sink.write('library ');
  +    _visitNode(node.name);
       sink.write(';');
     }
   
  
positive.code:       sink.write('await ');
      }
      sink.write('for (');
      safelyVisitNode(node.forLoopParts);
      sink.write(') ');
      safelyVisitNode(node.body);
    }
  
    @override
    void visitFunctionDeclaration(FunctionDeclaration node) {
      safelyVisitNodeListWithSeparatorAndSuffix(node.metadata, " ", " ");
      safelyVisitTokenWithSuffix(node.externalKeyword, " ");
      safelyVisitNodeWithSuffix(node.returnType, " ");
      safelyVisitTokenWithSuffix(node.propertyKeyword, " ");
      safelyVisitNode(node.name);
      safelyVisitNode(node.functionExpression);
    }
  
    @override
    void visitFunctionDeclarationStatement(FunctionDeclarationStatement node) {
      safelyVisitNode(node.functionDeclaration);
    }
  
    @override
    void visitFunctionExpression(FunctionExpression node) {
      safelyVisitNode(node.typeParameters);
      safelyVisitNode(node.parameters);
      if (node.body is! EmptyFunctionBody) {
        sink.write(' ');
      }
      safelyVisitNode(node.body);
    }
  
    @override
    void visitFunctionExpressionInvocation(FunctionExpressionInvocation node) {
      safelyVisitNode(node.function);
      safelyVisitNode(node.typeArguments);
      safelyVisitNode(node.argumentList);
    }
  
    @override
    void visitFunctionReference(FunctionReference node) {
      safelyVisitNode(node.function);
      safelyVisitNode(node.typeArguments);
    }
  
    @override
    void visitFunctionTypeAlias(FunctionTypeAlias node) {
      safelyVisitNodeListWithSeparatorAndSuffix(node.metadata, " ", " ");
      sink.write("typedef ");
      safelyVisitNodeWithSuffix(node.returnType, " ");
      safelyVisitNode(node.name);
      safelyVisitNode(node.typeParameters);
      safelyVisitNode(node.parameters);
      sink.write(";");
    }
  
    @override
    void visitFunctionTypedFormalParameter(FunctionTypedFormalParameter node) {
      safelyVisitNodeListWithSeparatorAndSuffix(node.metadata, ' ', ' ');
      safelyVisitTokenWithSuffix(node.requiredKeyword, ' ');
      safelyVisitTokenWithSuffix(node.covariantKeyword, ' ');
      safelyVisitNodeWithSuffix(node.returnType, " ");
      safelyVisitNode(node.identifier);
      safelyVisitNode(node.typeParameters);
      safelyVisitNode(node.parameters);
      if (node.question != null) {
        sink.write('?');
      }
  
negative.code: 
    @override
    void visitSetOrMapLiteral(SetOrMapLiteral node) {
      _visitToken(node.constKeyword, suffix: ' ');
      _visitNode(node.typeArguments);
      sink.write('{');
      _visitNodeList(node.elements, separator: ', ');
      sink.write('}');
    }
  
    @override
    void visitShowCombinator(ShowCombinator node) {
      sink.write('show ');
      _visitNodeList(node.shownNames, separator: ', ');
    }
  
    @override
    void visitSimpleFormalParameter(SimpleFormalParameter node) {
      _visitNodeList(node.metadata, separator: ' ', suffix: ' ');
      _visitToken(node.requiredKeyword, suffix: ' ');
      _visitToken(node.covariantKeyword, suffix: ' ');
      _visitToken(node.keyword, suffix: ' ');
      _visitNode(node.type);
      if (node.type != null && node.identifier != null) {
        sink.write(' ');
      }
      _visitNode(node.identifier);
    }
  
    @override
  