Incorrect "used but not defined" note

[Dkatzman2002]

File test.lipsp:
===
(defstruct (grobit) (boop nil :type symbol))

(defun test-use-not-defined (x) (copy-grobit x)) ; auto-defined
===
CL-USER(1): (compile-file "/tmp/test.lisp")
; Compiling /tmp/test.lisp ...
; (DEFSTRUCT (GROBIT) ...)
; (DEFUN TEST-USE-NOT-DEFINED ...)

; Compilation unit finished
; The following functions were used but not defined:
; COPY-GROBIT

; Wrote /tmp/test.abcl (0.161 seconds)