[registrar] Fix generic argument check to allow INativeObject. Fixes …

…#52868. (#1788)

https://bugzilla.xamarin.com/show_bug.cgi?id=52868

tests/mtouch/RegistrarTest.cs

@@ -696,6 +696,21 @@ class FutureType : NSObject
 			        ".*/Test.cs(.*): error MT4164: Cannot export the property 'Complex' because its selector '_Complex' is an Objective-C keyword. Please use a different name.");
 		}
 
+		[Test]
+		public void MT4167 ()
+		{
+			var code = @"
+class X : ReplayKit.RPBroadcastControllerDelegate
+{
+	public override void DidUpdateServiceInfo (ReplayKit.RPBroadcastController broadcastController, NSDictionary<NSString, INSCoding> serviceInfo)
+	{
+		throw new NotImplementedException ();
+	}
+}
+";
+			Verify (R.Static, code, true);
+		}
+
 		[Test]
 		public void MultiplePropertiesInHierarchy ()
 		{

tools/common/StaticRegistrar.cs

@@ -1968,9 +1968,9 @@ string ToObjCParameterType (TypeReference type, string descriptiveMethodName, Li
 					if (i > 0)
 						sb.Append (", ");
 					var argumentType = git.GenericArguments [i];
-					if (!IsNSObject (argumentType)) {
+					if (!IsINativeObject (argumentType)) {
 						// I believe the generic constraints we have should make this error impossible to hit, but better safe than sorry.
-						AddException (ref exceptions, CreateException (4167, inMethod.Resolve () as MethodDefinition, "Cannot register the method '{0}' because the signature contains a generic type ({1}) with a generic argument type that isn't an NSObject subclass ({2}).", descriptiveMethodName, GetTypeFullName (type), GetTypeFullName (argumentType)));
+						AddException (ref exceptions, CreateException (4167, inMethod.Resolve () as MethodDefinition, "Cannot register the method '{0}' because the signature contains a generic type ({1}) with a generic argument type that doesn't implement INativeObject ({2}).", descriptiveMethodName, GetTypeFullName (type), GetTypeFullName (argumentType)));
 						return "id";
 					}
 					sb.Append (ToObjCParameterType (argumentType, descriptiveMethodName, exceptions, inMethod));

tools/mtouch/error.cs

@@ -305,7 +305,7 @@ namespace Xamarin.Bundler {
 	//					MT4164	Cannot export the property '{0}' because its selector '{1}' is an Objective-C keyword. Please use a different name.
 	//					MT4165	The registrar couldn't find the type 'System.Void' in any of the referenced assemblies.
 	//					MT4166	Cannot register the method '{0}' because the signature contains a type ({1}) that isn't a reference type.
-	//					MT4167	Cannot register the method '{0}' because the signature contains a generic type ({1}) with a generic argument type that isn't an NSObject subclass ({2}).
+	//					MT4167	Cannot register the method '{0}' because the signature contains a generic type ({1}) with a generic argument type that doesn't implement INativeObject ({2}).
 	// MT5xxx	GCC and toolchain
 	//			MT51xx	compilation
 	//					MT5101	Missing '{0}' compiler. Please install Xcode 'Command-Line Tools' component