There was a plastic liner repair described in Appliance Service News a few years ago. You cut up small pieces of a matching color plastic, and put them in a small jar with lacquer thinner added. Leave it sit with the top on for a while.
The thinner "melts" the plastic, and turns it into a paste, which then can be applied, to fill in cracks, or I suppose small missing pieces. After it's applied, it the thinner evaporates, and it hardens.
I've used the method before, it makes a somewhat acceptable repair.