anchor.diff:    bool visitInterpolationString(InterpolationString node) {
       InterpolationString other = _other as InterpolationString;
       return isEqualTokens(node.contents, other.contents) &&
  -        node.value == other.value;
  +        failIfNotEqual(node, node.value, other, other.value);
     }
   
     @override
  
positive.code:   bool visitDoubleLiteral(DoubleLiteral node) {
      DoubleLiteral other = _other as DoubleLiteral;
      return isEqualTokens(node.literal, other.literal) &&
          node.value == other.value;
    }
  
    @override
  
negative.code: 
    @override
    bool visitAssertInitializer(AssertInitializer node) {
      AssertInitializer other = _other as AssertInitializer;
      return isEqualTokens(node.assertKeyword, other.assertKeyword) &&
          isEqualTokens(node.leftParenthesis, other.leftParenthesis) &&
          isEqualNodes(node.condition, other.condition) &&
  