https://paulgraham.com/ancomliser.html
Here's a list of problems people have reported in ANSI Common Lisp. I haven't
checked them all yet. The ones that say caught I have checked, the ones that say
reported I haven't.

p. 34. I should have said that our-equal works for "lists of symbols," rather
than just "lists". Caught by Bill Stratford.

p. 46. Richard Fateman points out that the best way to check for palindromes is
simply (equal x (reverse x)).

p. 57. To solve problem 3.6(b) you need to use a rest parameter, which is not
introduced until p. 102. Caught by Ricardo Ferreira de Oliveira.

p. 57. Problem 3.9 should say the longest path with no duplicates.

p. 60. The version of bin-search in figure 4.1 blows up if you give it an obj
which is smaller than the smallest element in vec. Reported by Richard Green.

p. 71. The definition of bst-remove is broken. Sorry about that! It and
bst-delete have been corrected in the source code. Caught by Chris Stover.

Chris Stover writes: "It is not enough to specify that (left child) < node <
(right child) for every node in the BST. The stronger property that max(left
subtree) < node < min(right subtree) is required. Without this stronger
property, the "bst-traverse" function in figure 4.8 does not necessarily list
elements in ascending order as claimed on page 75. (Example: a tree with root
node 1 having a single right child 2 which has a single left child 0.)
Fortunately, your "bst-insert" function in figure 4.5 preserves the correct BST
property. On the other hand, the correct BST property is not preserved in all
cases by the "bst-remove" function given in figure 4.6. A deleted internal node
needs to be replaced either by the maximal node in the left subtree or by the
minimal node in the right subtree, and your function does not do this."

Keke (surname unknown) gives an example:

> (setf nums nil)
NIL
> (dolist (x '(5 8 4 2 1 9 6 7 3))
    (setf nums (bst-insert x nums #'<)))
NIL
> (setf nums (bst-remove 5 nums #'<))
#<4>
> (bst-traverse #'princ nums)
13246789

p. 80. In exercise 4.5, the definition of bst-adjoin is identical to the
functionality of the already written bst-insert. Reported by Richard Green.

p. 97. In exercise 5.4, num-month should be month-num. Caught by David Sletten.

p. 120. "there should be single line" should have an "a" in it. Caught by Marcel
Molina Jr.

p. 165. In the definition of quicksort, > should be >= on lines 12 and 13.
Reported by Jed Crosby.

p. 177. Pierpaolo Bernardi reports that bubble sort should be selection sort.

p. 203. The definition of bst-delete is broken. See note on p. 71.

p. 204. In the last full paragraph, "rest field" should be "next field". Caught
by Adam Langley.

p. 317. The template for cond has an extra set of parentheses. It should be
(cond (test expression*)*). Caught by Adam Jacobs.

p. 338 The :read-only-p defstruct slot option should be :read-only. Caught by
Laurent Peron.