@SuppressWarnings("unchecked")
  public <X> TypeDescriptor<T> where(
      TypeParameter<X> typeParameter, TypeDescriptor<X> typeDescriptor) {
    return where(typeParameter.typeVariable, typeDescriptor.getType());
  }
@Test
  public void testWhere() throws Exception {
    useWhereMethodToDefineTypeParam(new TypeDescriptor<String>() {});
  }