RecyclableLongListExtensions & ListExtensions cleaned up

Recyclable.Collections/RecyclableList.IList.cs

@@ -0,0 +1,118 @@
+using System.Collections;
+
+namespace Recyclable.Collections
+{
+	public partial class RecyclableList<T> : IList
+	{
+		public bool IsFixedSize => false;
+		public bool IsSynchronized => false;
+
+		private object? _syncRoot;
+		public object SyncRoot
+		{
+			get
+			{
+				if (_syncRoot == null)
+				{
+					_ = Interlocked.CompareExchange(ref _syncRoot, new object(), null);
+				}
+
+				return _syncRoot;
+			}
+		}
+
+		object? IList.this[int index]
+		{
+			get => _memoryBlock[index];
+
+			set
+			{
+				if (value is T typedValue)
+				{
+					new Span<T>(_memoryBlock)[index] = typedValue;
+				}
+				else if (value == null && _defaultIsNull)
+				{
+#nullable disable
+					new Span<T>(_memoryBlock)[index] = default;
+#nullable restore
+				}
+				else
+				{
+					ThrowArgumentOutOfRangeException(nameof(value), $"Argument is invalid. {(value != null ? "List element type is incompatible with the given value" : "Element is null and the list doesn't allow null values.")}");
+				}
+			}
+		}
+
+		public int Add(object? value)
+		{
+			if (value is T typeValue)
+			{
+				Add(typeValue);
+				return _count - 1;
+			}
+			else if (value == null && _defaultIsNull)
+			{
+				Add(null);
+				return _count - 1;
+			}
+			else
+			{
+				ThrowArgumentOutOfRangeException(nameof(value), $"Argument is invalid. {(value != null ? "List element type is incompatible with the given value" : "Element is null and the list doesn't allow null values.")}");
+				return RecyclableDefaults.ItemNotFoundIndex;
+			}
+		}
+
+		public bool Contains(object? value) => value is T typeValue
+			? Contains(typeValue)
+#nullable disable
+			: value == null && _defaultIsNull && Contains(default);
+#nullable restore
+
+		public int IndexOf(object? value) => value is T typeValue
+			? IndexOf(typeValue)
+			: value == null && _defaultIsNull
+#nullable disable
+			? IndexOf(default)
+#nullable restore
+			: RecyclableDefaults.ItemNotFoundIndex;
+
+		public void Insert(int index, object? value)
+		{
+			if (value is T typeValue)
+			{
+				Insert(index, typeValue);
+			}
+			else if (value == null && _defaultIsNull)
+			{
+#nullable disable
+				Insert(index, default);
+#nullable restore
+			}
+			else
+			{
+				ThrowArgumentOutOfRangeException(nameof(value), $"Argument is invalid. {(value != null ? "List element type is incompatible with the given value" : "Element is null and the list doesn't allow null values.")}");
+			}
+		}
+
+		public void Remove(object? value)
+		{
+			if (value is T typeValue)
+			{
+				_ = Remove(typeValue);
+			}
+			else if (value == null && _defaultIsNull)
+			{
+#nullable disable
+				_ = Remove(default);
+#nullable restore
+			}
+			else
+			{
+				ThrowArgumentOutOfRangeException(nameof(value), $"Argument is invalid. {(value != null ? "List element type is incompatible with the given value" : "Element is null and the list doesn't allow null values.")}");
+			}
+		}
+
+		public void CopyTo(Array array, int index) => Array.Copy(_memoryBlock, 0, array, index, _count);
+	}
+}