* immutable list is returned.)
   *
   * <p><b>Note:</b> in almost all circumstances, the returned {@link ImmutableList} retains a
   * strong reference to {@code this}, which may prevent the original list from being garbage
   * collected. If you want the original list to be eligible for garbage collection, you should
   * create and use a copy of the sub list (e.g., {@code

   * immutable list is returned.)
   *
   * <p><b>Note:</b> in almost all circumstances, the returned {@link ImmutableList} retains a
   * strong reference to {@code this}, which may prevent the original list from being garbage
   * collected. If you want the original list to be eligible for garbage collection, you should
   * create and use a copy of the sub list (e.g., {@code

  }

  public static <E> ImmutableList<E> copyOf(Collection<? extends E> elements) {
    if (elements instanceof ImmutableCollection) {
      /*
       * TODO: When given an ImmutableList that's a sublist, copy the referenced
       * portion of the array into a new array to save space?
       */
      @SuppressWarnings("unchecked") // all supported methods are covariant
      ImmutableCollection<E> list = (ImmutableCollection<E>) elements;