gistfile1.txt

CL-USER> (compile nil (lambda () (let ((x 33))
                                       (alexandria:once-only (x)
                                         
                                         42))))
; in: COMPILE ()
;     (ALEXANDRIA.0.DEV:ONCE-ONLY (X)
;       42)
; --> LET SB-INT:QUASIQUOTE SB-IMPL::|List| 
; ==>
;   (LET ((X #:ONCE-ONLY0))
;     42)
; 
; caught STYLE-WARNING:
;   The variable X is defined but never used.
; 
; compilation unit finished
;   caught 1 STYLE-WARNING condition
#<FUNCTION (LAMBDA ()) {52E579FB}>
NIL
NIL
CL-USER> (compile nil (lambda () (let ((x 33))
                                       (alexandria:once-only (x)
                                         (declare (ignorable x))
                                         42))))
#<FUNCTION (LAMBDA ()) {52E57C5B}>
NIL
NIL