namespace System.Collections.Immutable { public interface IImmutableList<T> : IReadOnlyList<T>, IReadOnlyCollection<T>, IEnumerable<T>, IEnumerable { IImmutableList<T> Clear(); int IndexOf(T item, int index, int count, IEqualityComparer<T> equalityComparer); int LastIndexOf(T item, int index, int count, IEqualityComparer<T> equalityComparer); IImmutableList<T> Add(T value); IImmutableList<T> AddRange(IEnumerable<T> items); IImmutableList<T> Insert(int index, T element); IImmutableList<T> InsertRange(int index, IEnumerable<T> items); IImmutableList<T> Remove(T value, IEqualityComparer<T> equalityComparer); IImmutableList<T> RemoveAll(Predicate<T> match); IImmutableList<T> RemoveRange(IEnumerable<T> items, IEqualityComparer<T> equalityComparer); IImmutableList<T> RemoveRange(int index, int count); IImmutableList<T> RemoveAt(int index); IImmutableList<T> SetItem(int index, T value); IImmutableList<T> Replace(T oldValue, T newValue, IEqualityComparer<T> equalityComparer); } }