anchor.diff:        whitespace();
       }
   
  +    _expectStatementSeparator();
  +
       return new VariableDeclaration(name, expression, scanner.spanFrom(start),
           guarded: guarded, global: global);
     }
  
positive.code: 
    /// Consumes a statement that's allowed at the top level of the stylesheet.
    Statement _topLevelStatement() {
      if (scanner.peekChar() == $at)
        return _atRule(_topLevelStatement, root: true);
      return _styleRule();
    }
  
    /// Consumes a variable declaration.
  
negative.code:     var value = _almostAnyValue();
      var optional = scanner.scanChar($exclamation);
      if (optional) expectIdentifier("optional");
      _expectStatementSeparator();
      return new ExtendRule(value, scanner.spanFrom(start), optional: optional);
    }
  
  