Comment 1 for bug 1209272

Faré adds:

There was a PCL problem in CMUCL preventing upgrade from ASDF2. I was
hoping that from ASDF3 to ASDF3, the lack of effective class
redefinition (all defclasses are to the thing as before) would avoid
the problem. Apparently not.

Raymond: an interesting thing to do would be to dig into old versions
of CMUCL to see if they used to support this kind of upgrade and we
can locate a PCL patch that broke it.