Homeowner currently undergoing gut renovation on bathroom. The tub is being converted to a walk in shower which necessitates going from current 1 1/2 drain to a 2 inch. Permit has been pulled. Old drain was 1 1/2 inch copper. Plumber has replaced with 2 inch PVC. Please see attached pic of the connection at the cast iron stack. I would have assumed he would use a Fernco to make the connection. Instead it looks like he kept the stub of the copper in place and crudely slid a burned/ melted section of PVC over it (to disguise it?). I will address this with the plumber tomorrow. Just wanted a pros opinion first.