anchor.diff:  ./
   
   TopLevel: T_FEED_JS_EXPRESSION Expression ;
  +/.
  +case $rule_number: {
  +  sym(1).Node = sym(2).Node;
  +  program = sym(1).Node;
  +} break;
  +./
  +
  +TopLevel: T_FEED_JS_SOURCE_ELEMENT Expression ;
   /.
   case $rule_number: {
     sym(1).Node = sym(2).Node;
  
positive.code: %token T_FEED_UI_OBJECT_MEMBER
  %token T_FEED_JS_STATEMENT
  %token T_FEED_JS_EXPRESSION
  
  %nonassoc SHIFT_THERE
  %nonassoc T_IDENTIFIER T_COLON T_SIGNAL T_PROPERTY T_READONLY
  
negative.code:     bool parse() { return parse(T_FEED_UI_PROGRAM); }
      bool parseStatement() { return parse(T_FEED_JS_STATEMENT); }
      bool parseExpression() { return parse(T_FEED_JS_EXPRESSION); }
      bool parseSourceElement() { return parse(T_FEED_JS_SOURCE_ELEMENT); }
      bool parseUiObjectMember() { return parse(T_FEED_UI_OBJECT_MEMBER); }
  
      AST::UiProgram *ast() const
  