Remove usage of TypeSwitch.

src/Workspaces/Core/Portable/Shared/Utilities/EnumValueUtilities.cs

@@ -79,16 +79,18 @@ private static object CreateOne(SpecialType specialType)
 
         private static IComparable Multiply(IComparable value, uint number)
         {
-            return value.TypeSwitch(
-                (long v) => unchecked((long)(v * number)),
-                (ulong v) => unchecked((ulong)(v * number)),
-                (int v) => unchecked((int)(v * number)),
-                (uint v) => unchecked((uint)(v * number)),
-                (short v) => unchecked((short)(v * number)),
-                (ushort v) => unchecked((ushort)(v * number)),
-                (sbyte v) => unchecked((sbyte)(v * number)),
-                (byte v) => unchecked((byte)(v * number)),
-                _ => (IComparable)null);
+            switch (value)
+            {
+                case long v: return unchecked((long)(v * number));
+                case ulong v: return unchecked((ulong)(v * number));
+                case int v: return unchecked((int)(v * number));
+                case uint v: return unchecked((uint)(v * number));
+                case short v: return unchecked((short)(v * number));
+                case ushort v: return unchecked((ushort)(v * number));
+                case sbyte v: return unchecked((sbyte)(v * number));
+                case byte v: return unchecked((byte)(v * number));
+                default: return null;
+            }
         }
 
         private static IComparable Add(IComparable value, uint number)