Comment 6 for bug 1873556

I think it is always wrong to expect code to be readable without problems without *print-gensym* (and/or *print-readably*, *print-circle*). I don't want to support "you might be able to read this with *print-gensym* set to nil, 99% of the time, but some other times you won't" -- I'd much rather be able to tell people "well don't do that then".

If you want reproducibility, you need to have deterministic numbering. And while we might be able to have non-colliding numbering in most cases, I don't want to have to guarantee it. But, importantly, if you have reproducibility, you can get readability with appropriate use of printer and reader control variables; if you don't have reproducibility, no amount of fiddling with control variables will give it to you.