Fix NullReferenceException in IncorrectExceptionParameterOrderingIssue.

ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/IncorrectExceptionParameterOrderingIssue.cs

@@ -63,8 +63,8 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 					return;
 				var firstParam = parameters.FirstOrNullObject() as PrimitiveExpression;
 				var secondParam = parameters.LastOrNullObject() as PrimitiveExpression;
-				if (firstParam == null || firstParam.Value.GetType() != typeof(string) ||
-					secondParam == null || firstParam.Value.GetType() != typeof(string))
+				if (firstParam == null || !(firstParam.Value is string) ||
+					secondParam == null || !(secondParam.Value is string))
 					return;
 				var type = context.Resolve(objectCreateExpression.Type) as TypeResolveResult;
 				if (type == null)

ICSharpCode.NRefactory.Tests/CSharp/CodeIssues/IncorrectExceptionParameterOrderingTests.cs

@@ -79,6 +79,7 @@ class A
 		throw new ArgumentException (""The parameter 'blah' can not be null"", ""blah"");
 		throw new ArgumentOutOfRangeException (""blah"", ""The parameter 'blah' can not be null"");
 		throw new DuplicateWaitObjectException (""blah"", ""The parameter 'blah' can not be null"");
+		throw new ArgumentOutOfRangeException (""blah"", 42);
 	}
 }";
 			TestRefactoringContext context;