Imported Upstream version 3.6.0

Former-commit-id: da6be194a6b1221998fc28233f2503bd61dd9d14

mcs/tests/dtest-optional-01.cs

@@ -0,0 +1,59 @@
+using System;
+using System.Reflection;
+using System.Runtime.InteropServices;
+
+struct S
+{
+}
+
+public class G<T>
+{
+
+	public object M1 (T o = default (T))
+	{
+		return o;
+	}
+
+	public object M2 ([Optional] T o)
+	{
+		return o;
+	}
+}
+
+public class C
+{
+	public static object Test ([Optional] dynamic a)
+	{
+		return a;
+	}
+	
+	void TestS (S s = default (S))
+	{
+	}
+	
+	object TestD (dynamic o = null)
+	{
+		return o;
+	}
+
+	public static int Main ()
+	{
+		if (Test () != Missing.Value)
+			return 1;
+		
+		dynamic d = new C ();
+		d.TestS ();
+		
+		if (d.TestD () != null)
+			return 2;
+			
+		d = new G<string> ();
+		if (d.M1 () != null)
+			return 3;
+			
+		if (d.M2 () != null)
+			return 4;
+		
+		return 0;
+	}
+}