* @since 15.0
   */
  public final boolean isPrimitive() {
    return (runtimeType instanceof Class) && ((Class<?>) runtimeType).isPrimitive();
  }

  /**
   * Returns the corresponding wrapper type if this is a primitive type; otherwise returns {@code
   * this} itself. Idempotent.
   *
   * @since 15.0
   */
  public final TypeToken<T> wrap() {
    if (isPrimitive()) {

  }

  private static void assertIsPrimitive(TypeToken<?> type) {
    assertTrue(type.isPrimitive());
    assertNotWrapper(type);
    assertEquals(TypeToken.of(Primitives.wrap((Class<?>) type.getType())), type.wrap());
  }

  private static void assertNotPrimitive(TypeToken<?> type) {
    assertFalse(type.isPrimitive());
    assertThat(type.wrap()).isEqualTo(type);
  }

  }

  private static void assertIsPrimitive(TypeToken<?> type) {
    assertTrue(type.isPrimitive());
    assertNotWrapper(type);
    assertEquals(TypeToken.of(Primitives.wrap((Class<?>) type.getType())), type.wrap());
  }

  private static void assertNotPrimitive(TypeToken<?> type) {
    assertFalse(type.isPrimitive());
    assertThat(type.wrap()).isEqualTo(type);
  }