expand.n

def _N_initializedObject_5972 = entity();
  _  = 
  {
    def _N_initializedObject_5973 = _N_initializedObject_5972.Foo;
    _  = 
    {
      def _N_initializedObject_5974 = if (Object.ReferenceEquals(_N_initializedObject_5973.Baz, null)) Combinators.entity(); else _N_initializedObject_5973.Baz;
      _N_initializedObject_5974.Age = 3;
      _N_initializedObject_5974
    };
    _N_initializedObject_5973
  };
  _N_initializedObject_5972
}

src.n

class Baz { public Age : int { get; set } }
class Foo { public Baz : Baz { get; set } }
class Bar { public Foo : Foo { get; set } }

module Bug1
  public Test() : Bar
    entity() <- 
      Foo <<- 
        Baz <-
          Age = 3