diff --git a/tests/xharness/Microsoft.DotNet.XHarness.iOS.Shared/XmlResultParser.cs b/tests/xharness/Microsoft.DotNet.XHarness.iOS.Shared/XmlResultParser.cs
index d9c6ea3312e9..0e2f448484ba 100644
--- a/tests/xharness/Microsoft.DotNet.XHarness.iOS.Shared/XmlResultParser.cs
+++ b/tests/xharness/Microsoft.DotNet.XHarness.iOS.Shared/XmlResultParser.cs
@@ -348,7 +348,7 @@ static TrxTests ParseTrxXml (XmlReader reader)
 		{
 			var rv = new TrxTests ();
 			var tests = new Dictionary<string, TrxTest> ();
-			TrxTest lastTest = null;
+			TrxTest? lastTest = null;
 			while (reader.Read ()) {
 				if (reader.NodeType != XmlNodeType.Element)
 					continue;