On sbcl and ccl, number is strange

[commander-trashdin]

Number is NOT a subtypep of (or real complex). You have your own subtypep so you probably do not care, but still informing you about this. More here: https://www.reddit.com/r/Common_Lisp/comments/nm4glc/real_and_complex_are_somehow_not_all_numbers/

[Bike]

It's true the standard doesn't define that complex and real define the entire space of number. Could be another config flag I guess, but I don't know if any implementations actually allow defining quaternions or whatnot.