using System.Collections.Generic; using System.Runtime.CompilerServices; namespace System.Collections.Frozen { internal sealed class EmptyFrozenDictionary<TKey, TValue> : FrozenDictionary<TKey, TValue> { private protected override TKey[] KeysCore => Array.Empty<TKey>(); private protected override TValue[] ValuesCore => Array.Empty<TValue>(); private protected override int CountCore => 0; internal EmptyFrozenDictionary(IEqualityComparer<TKey> comparer) : base(comparer) { } private protected override Enumerator GetEnumeratorCore() { return new Enumerator(Array.Empty<TKey>(), Array.Empty<TValue>()); } [return: System.Runtime.CompilerServices.IsReadOnly] private protected override ref TValue GetValueRefOrNullRefCore(TKey key) { return ref Unsafe.NullRef<TValue>(); } } }