Comment 1 for bug 458164

as discussed on #lisp, it would be wrong to put, let's say a NIL in the class-prototype slot of LIST. even though it would be typep 'list, but it's still wrong...

but then, why the integer 42 (i know, why, but still...)?

this can lead to hard to track down bugs...

i propose to signal an error, or return at least 'builtin-classes-have-no-sane-prototypes, or something that gives a hint for users staring at the debugger...