Imported Upstream version 3.6.0

Former-commit-id: da6be194a6b1221998fc28233f2503bd61dd9d14

mcs/tests/gtest-152.cs

@@ -0,0 +1,47 @@
+using System;
+
+public interface IFoo
+{
+	IFoo Hello ();
+}
+
+public interface IFoo<T> : IFoo
+{
+	new IFoo<T> Hello ();
+}
+
+public interface ICollectionValue<T>: IFoo<T>
+{
+}
+
+public interface ICollection<T>: ICollectionValue<T>
+{ }
+
+public abstract class EnumerableBase<T> : IFoo<T>
+{
+	public abstract IFoo<T> Hello();
+
+	IFoo IFoo.Hello ()
+	{
+		return Hello ();
+	}
+}
+
+public abstract class CollectionBase<T> : EnumerableBase<T>
+{
+}
+
+public class HashBag<T>: CollectionBase<T>, ICollection<T>
+{
+	public override IFoo<T> Hello ()
+	{
+		return this;
+	}
+}
+
+class X
+{
+	public static void Main ()
+	{
+	}
+}