FactoryMethodDescriptor build() {
      FactoryMethodDescriptor descriptor = buildImpl();
      checkState(
          descriptor
              .creationParameters()
              .equals(Sets.union(descriptor.passedParameters(), descriptor.providedParameters())));
      return descriptor;
    }
The parameters of the constructor that this {@code create} method calls. This is the union of
{@link #passedParameters()} and {@link #providedParameters()}.
factory/src/main/java/com/google/auto/factory/processor/FactoryMethodDescriptor.java