text: declare class C {
    static [[foo]]: T
  }
  declare class C {
    [[foo]]: T
  }
  interface I {
    [[foo]]: X
  }
  interface I {
    [[foo]]() => X
  }
  type T1 = {
    [[foo]]: X
  };
  type T2 = {
    [[foo]]() => X
  };
  type T3 = {
    [[foo]]?: X
  };