anchor.diff:  
     accept(Visitor visitor) => visitor.visitAwait(this);
   
  +  accept1(Visitor1 visitor, arg) => visitor.visitAwait(this, arg);
  +
     visitChildren(Visitor visitor) {
       expression.accept(visitor);
  +  }
  +
  +  visitChildren1(Visitor1 visitor, arg) {
  +    expression.accept1(visitor, arg);
     }
   
     Token getBeginToken() => awaitToken;
  
positive.code: 
    accept(Visitor visitor) => visitor.visitPart(this);
  
    visitChildren(Visitor visitor) => uri.accept(visitor);
  
    Token getBeginToken() => partKeyword;
  
  
negative.code: 
    accept(Visitor visitor) => visitor.visitEmptyStatement(this);
  
    accept1(Visitor1 visitor, arg) => visitor.visitEmptyStatement(this, arg);
  
    visitChildren(Visitor visitor) {}
  
    visitChildren1(Visitor1 visitor, arg) {}
  
    Token getBeginToken() => semicolonToken;
  
  