On 23-02-2023 12:38, Ludovic Courtès wrote:
> Do you have a simple reproducer and a before/after comparison showing
> what Guile prints?

Simpler reproducer:

(define-syntax syntax-stuff-twice
   (lambda (s)
     (define (f x)
       (syntax-case x ()
         (#:this #''this)
         (#:that #''that)))
     (define (g y)
       (syntax-case y ()
         (#:cat #''cat)
         (#:dog #''dog)))
     (syntax-case s ()
       ((_)
        ;; Let's compute some syntax, for some reason.
        ;; (Hence, the syntax doesn't have line information
        ;; that might be an acceptable alternative to
        ;; a backtrace.)
        (let ((x (datum->syntax #f "foo"))
              (y (datum->syntax #f "bar")))
          #`(list #,(f x) #,(g y)))))))

(syntax-stuff-twice 'this #:cat) ; <- L21
;; Before:
;; .../reproducer.scm:21:0: source expression failed to match any 
pattern in form (quote this)
;;
;; After: ??? the same thing! Looks like another patch is needed.

Looks like the patch I sent doesn't actually accomplish what it was 
supposed to solve ...

Greetings,
Maxime.