return subtype;
  }

  /**
   * Returns true if this type is a supertype of the given {@code type}. "Supertype" is defined
   * according to <a
   * href="https://docs.oracle.com/javase/specs/jls/se25/html/jls-4.html#jls-4.5.1">the rules for
   * type arguments</a> introduced with Java generics.
   *
   * @since 19.0
   */
  public final boolean isSupertypeOf(TypeToken<?> type) {