Imported Upstream version 4.0.1

Former-commit-id: 6d37e02debfe41dd5c13ba6f6a2428c8b1ff5e28

mcs/tests/test-anon-177.cs

@@ -0,0 +1,25 @@
+using System;
+using System.Linq;
+using System.Collections.Generic;
+
+class X
+{
+	public static void Execute<TArg>(TArg args)
+	{
+		Action a = () => {
+			List<string> s = new List<string> () {
+				"test"
+			};
+
+			object res = null;
+			var res2 = s.Select(acrl => acrl.Select(acr => res)).ToArray ();
+		};
+
+		a ();
+	}
+
+	public static void Main ()
+	{
+		Execute<string> (null);
+	}
+}

mcs/tests/test-null-operator-011.cs

@@ -0,0 +1,12 @@
+static class Crash
+{
+	static string GetFoo ()
+	{
+		return null;
+	}
+
+	static void Main ()
+	{
+		(GetFoo ()?.ToLower ()).ToUpper ();
+	}
+}