using System;

public interface IHello[T]
{ }

public interface IFoo[T]
{
   GetHello () : IHello[T];
}

public interface IBar[T] : IFoo[T]
{ }

public class Foo[T] : IBar[T], IFoo[T]
{
  public GetHello () :  Hello
  {
      Hello (this);
  }
        this ()
  {
      _ = Hello (this);
  }

  public class Hello : IHello[T]
  {
    public  Foo : Foo[T];

    public this (mutable  foo : Foo[T])
    {
      this.Foo = foo;
    }
  }
}

class X
{
  static Main () :  void
  { }
}

/*

mono generated EXE verifies fine though, this is because of
DefineMethodOverride bug in MS.NET
NO-VERIFY

BEGIN-OUTPUT
END-OUTPUT
*/