Cleanup: use pattern matching

Author: rameel

Main/src/Algorithms/HashCode.cs

@@ -144,8 +144,7 @@ public static int CombineValues<T>([CanBeNull, InstantHandle] IEnumerable<T> val
 
 			var hashCode = 0;
 
-			var list = values as IList<T>;
-			if (list != null)
+			if (values is IList<T> list)
 			{
 				for (int i = 0, count = list.Count; i < count; i++)
 				{

Main/src/Collections/Enumerable/EnumerableExtensions.Slice.cs

@@ -34,13 +34,12 @@ public static IEnumerable<T> Slice<T>([NotNull] this IEnumerable<T> source, int
 			if (count <= 0)
 				return Enumerable.Empty<T>();
 
-			var list = source as IList<T>;
-			if (list == null)
-				return SliceImpl(source, startIndex, count);
-
+		if (source is IList<T> list)
 			return startIndex != 0 || list.Count > count
 				? SliceImpl(list, startIndex, count)
 				: list;
+
+			return SliceImpl(source, startIndex, count);
 		}
 
 		private static IEnumerable<T> SliceImpl<T>(IList<T> list, int index, int count)

Main/src/Collections/Enumerable/EnumerableExtensions.TakeLast.cs

@@ -28,13 +28,12 @@ public static IEnumerable<T> TakeLast<T>([NotNull] this IEnumerable<T> source, i
 			if (count <= 0)
 				return Enumerable.Empty<T>();
 
-			var list = source as IList<T>;
-			if (list == null)
-				return TakeLastImpl(source, count);
-
+		if (source is IList<T> list)
 			return count < list.Count
 				? TakeLastImpl(list, count)
 				: list;
+
+			return TakeLastImpl(source, count);
 		}
 
 		private static IEnumerable<T> TakeLastImpl<T>(IList<T> source, int count)

Main/src/Collections/Enumerable/IndexedItem.cs

@@ -74,6 +74,7 @@ public IndexedItem(T item, int index, bool isFirst, bool isLast) : this()
 		public override bool Equals(object obj)
 		{
 			if (ReferenceEquals(null, obj)) return false;
+			// ReSharper disable once MergeCastWithTypeCheck
 			return obj is IndexedItem<T> && Equals((IndexedItem<T>)obj);
 		}
 

Main/src/ExceptionExtensions.cs

@@ -43,9 +43,7 @@ public static StringBuilder ToDiagnosticString(this Exception exception, [NotNul
 				if (ex.StackTrace.NotNullNorEmpty())
 					stringBuilder.AppendLine(ex.StackTrace);
 
-				var notFoundException = ex as FileNotFoundException;
-
-				if (notFoundException != null)
+				if (ex is FileNotFoundException notFoundException)
 				{
 					var fex = notFoundException;
 

Main/src/Expressions/ExpressionExtensions.GetMembers.cs

@@ -29,8 +29,7 @@ public static MemberInfo GetMemberInfo([NotNull] this LambdaExpression expressio
 			Code.NotNull(expression, nameof(expression));
 
 			var body = expression.Body;
-			var unary = body as UnaryExpression;
-			if (unary != null)
+			if (body is UnaryExpression unary)
 				body = unary.Operand;
 
 			switch (body.NodeType)
@@ -140,8 +139,7 @@ private static string GetFullPropertyNameImpl(MemberExpression expression)
 		private static MemberExpression GetMemberExpression(LambdaExpression expression)
 		{
 			var body = expression.Body;
-			var unary = body as UnaryExpression;
-			return unary != null
+			return body is UnaryExpression unary
 				? (MemberExpression)unary.Operand
 				: (MemberExpression)body;
 		}
@@ -159,8 +157,7 @@ public static MemberInfo[] GetMembersInfo([NotNull] this LambdaExpression expres
 			Code.NotNull(expression, nameof(expression));
 
 			var body = expression.Body;
-			var unary = body as UnaryExpression;
-			if (unary != null)
+			if (body is UnaryExpression unary)
 				body = unary.Operand;
 
 			return GetMembers(body).Reverse().ToArray();

Main/src/Ranges/[Boundaries]/RangeBoundaryFrom`1.cs

@@ -517,11 +517,13 @@ public int CompareTo(T other) =>
 		[Pure]
 		int IComparable.CompareTo(object obj)
 		{
+			// ReSharper disable once UsePatternMatching
 			var otherA = obj as RangeBoundaryFrom<T>?;
 			if (otherA != null)
 			{
 				return CompareTo(otherA.GetValueOrDefault());
 			}
+			// ReSharper disable once UsePatternMatching
 			var otherB = obj as RangeBoundaryTo<T>?;
 			if (otherB != null)
 			{

Main/src/Structures/Option/ValueOption`1.cs

@@ -88,6 +88,7 @@ public bool Equals(ValueOption<T> other) =>
 		public override bool Equals(object obj)
 		{
 			if (ReferenceEquals(null, obj)) return false;
+			// ReSharper disable once MergeCastWithTypeCheck
 			return obj is ValueOption<T> && Equals((ValueOption<T>)obj);
 		}