text: function shouldBe(actual, expected) {
      if (actual !== expected)
          throw new Error('bad value: ' + actual);
  }
  
  var builtin = createBuiltin(`(function (a) {
      return @argument(0);
  })`);
  
  (function () {
      for (var i = 0; i < 1e4; ++i) {
          shouldBe(builtin(), undefined);
          shouldBe(builtin(42), 42);
      }
  }());
  