Argument names coming out as NIL

[Moon at MIT-AI (David A. Moon)]

In system 20, if you find that c-t-A in the editor, or the arglist
function, is claiming that the arguments to a function are all called
"NIL", that function needs to be recompiled; there was a certain period
when the compiler was generating the wrong thing.  Please send in a bug
report listing any of these that you find, or if it's in your own program,
just recompile it.