bug#2179: 23.0.60; define-key vs define-key-after key syntax

This may or may not be a bug, but it caused me some pain, so I am 
pointing it out.

(define-key my-map [(control l)] 'do-something)

works as expected, but

(define-key-after my-map [(control l)] 'do-something)

does not.  The reason is that define-key does a lot of work to allow
for a wide range of key syntaxes, but define-key-after just does:

(setq key
      (if (<= (length key) 1) (aref key 0) ...

and (control l) must get mapped to ?\C-l = 12 to be useful in a keymap.
As I say, I'm not sure this is a bug, but it was rather
counter-intuitive to me, so maybe a warning to this effect in the
documentation for define-key-after would be sufficient.  The current
documentation says "... This is like `define-key' except that the binding
for KEY is placed just after the binding for the event AFTER ..."

Cheers,
Gerard