anchor.diff:                [operator.lexeme]);
             return new PrefixExpression(
                 operator,
  -              new SuperExpression(andAdvance));
  +              new SuperExpression(getAndAdvance()));
           }
         }
         return new PrefixExpression(operator, _parseAssignableExpression(false));
  
positive.code:       SimpleIdentifier stackTraceParameter = null;
        Token rightParenthesis = null;
        if (_matchesKeyword(Keyword.CATCH)) {
          catchKeyword = andAdvance;
          leftParenthesis = _expect(TokenType.OPEN_PAREN);
          exceptionParameter = parseSimpleIdentifier();
          if (_matches(TokenType.COMMA)) {
            comma = andAdvance;
            stackTraceParameter = parseSimpleIdentifier();
          }
          rightParenthesis = _expect(TokenType.CLOSE_PAREN);
  
negative.code:       _reportErrorForCurrentToken(ParserErrorCode.TYPEDEF_IN_CLASS);
        // TODO(brianwilkerson) We don't currently have any way to capture the
        // function type alias that was parsed.
        _parseFunctionTypeAlias(commentAndMetadata, getAndAdvance());
        return null;
      }
      TypeName type = parseTypeName();
  