Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

mcs/errors/cs9030.cs

@@ -0,0 +1,13 @@
+// CS9030: The left-hand side of an assignment cannot contain a null propagating operator
+// Line: 11
+
+using System;
+
+class MainClass
+{
+	public static void Main ()
+	{
+		System.AppDomain a = null;
+		a?.AssemblyLoad += (sender, args) => Console.Write (args);
+	}
+}