anchor.diff:      whitespace();
   
       var positional = <Expression>[];
  -    var named = <String, Expression>{};
  +    var named = normalizedMap/*<Expression>*/();
       Expression rest;
       Expression keywordRest;
       while (_lookingAtExpression()) {
  
positive.code: 
        if (expression is VariableExpression && scanner.scanChar($colon)) {
          whitespace();
          named[expression.name] = _expressionUntilComma();
        } else if (scanner.scanChar($dot)) {
          scanner.expectChar($dot);
  
negative.code:     whitespace();
      var children = this.children(_functionAtRule);
  
      return new FunctionRule(name, arguments, children, scanner.spanFrom(start));
    }
  
  