Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

mcs/class/corlib/System/Delegate.cs

@@ -524,17 +524,9 @@ namespace System
 		/// </symmary>
 		public static Delegate Combine (Delegate a, Delegate b)
 		{
-			if (a == null) {
-				if (b == null)
-					return null;
+			if (a == null)
 				return b;
-			} else 
-				if (b == null)
-					return a;
 
-			if (a.GetType () != b.GetType ())
-				throw new ArgumentException (Locale.GetText ("Incompatible Delegate Types. First is {0} second is {1}.", a.GetType ().FullName, b.GetType ().FullName));
-			
 			return a.CombineImpl (b);
 		}