usedTypes.clear();
            }
        }
    }

    @Override
    public Optional<Type> lookup(String id) {
        return Optional.of(require(id));
    }

    @Override
    @Nonnull
    public Type require(String id) {
        nonNull(id, "id");
        return usedTypes.computeIfAbsent(id, i -> {
            Type type = types.get(id);
            if (type == null) {

     * Shortcut for {@code getService(TypeRegistry.class).require(...)}.
     *
     * @see org.apache.maven.api.services.TypeRegistry#require(String)
     */
    @Nonnull
    Type requireType(@Nonnull String id);

    /**
     * Obtain the {@link Language} from the specified {@code id}.
     * <p>
     * Shortcut for {@code getService(LanguageRegistry.class).require(...)}.
     *

     * create a custom {@code Type} for it.
     *
     * @param id the id of the type to retrieve
     * @return the type
     */
    @Nonnull
    @Override
    default Type require(@Nonnull String id) {
        return lookup(id).orElseThrow(() -> new IllegalArgumentException("Unknown extensible enum value '" + id + "'"));
    }

            }
        };
    }

    @Provides
    static PackagingRegistry newPackagingRegistry(TypeRegistry typeRegistry) {
        return id -> Optional.of(new DumbPackaging(id, typeRegistry.require(id), Map.of()));
    }

    @Provides
    static TypeRegistry newTypeRegistry(List<TypeProvider> providers) {
        return new TypeRegistry() {
            @Override

   * reconstructed using public factory methods. This ensures that the implementation types remain
   * as implementation details.
   *
   * <p>Since the bimap is immutable, ImmutableBiMap doesn't require special logic for keeping the
   * bimap and its inverse in sync during serialization, the way AbstractBiMap does.
   */
  @J2ktIncompatible // serialization

      TypeVariable<?>[] typeVars = rawType.getTypeParameters();
      for (int i = 0; i < params.size(); i++) {
        TypeToken<?> paramType = type.resolveType(typeVars[i]);
        // We require all @Generates methods to either be parameter-less or accept non-null
        // values for their generic parameter types.
        Object argValue = generate(paramType);
        if (argValue == null) {

        return getService(TypeRegistry.class).require(id);
    }

    @Override
    public Language requireLanguage(String id) {
        return getService(LanguageRegistry.class).require(id);
    }

    @Override
    public Packaging requirePackaging(String id) {
        return getService(PackagingRegistry.class).require(id);
    }

    @Override

      TypeVariable<?>[] typeVars = rawType.getTypeParameters();
      for (int i = 0; i < params.size(); i++) {
        TypeToken<?> paramType = type.resolveType(typeVars[i]);
        // We require all @Generates methods to either be parameter-less or accept non-null
        // values for their generic parameter types.
        Object argValue = generate(paramType);
        if (argValue == null) {

   *       (In simple cases, callers can avoid this by registering all tasks with the same {@link
   *       MoreExecutors#newSequentialExecutor} wrapper around {@code directExecutor()}. More
   *       complex cases may require using thread pools or making deeper changes.)
   *   <li>If an exception propagates out of a {@code Runnable}, it is not necessarily seen by any

   * nullness checker can already "prove" are non-null. That means that the first parameter to
   * checkNotNull *should* be annotated to require it to be non-null.
   *
   * However, for a variety of reasons, Google developers have written a ton of code over the past
   * decade that assumes that they can use checkNotNull for non-precondition checks. I had hoped to