bug#56799: [PATCH v2] gexp: Handle *unspecified* as a gexp input.

[Maxim Cournoyer]

Fixes <https://issues.guix.gnu.org/56799>.

* guix/gexp.scm (gexp->sexp)[*unspecified*]: Quote value when encountering it.
---
 guix/gexp.scm | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/guix/gexp.scm b/guix/gexp.scm
index ef92223048..e05aed6f32 100644
--- a/guix/gexp.scm
+++ b/guix/gexp.scm
@@ -1380,6 +1380,8 @@ (define* (reference->sexp ref #:optional native?)
                                 #:output output)))
         (($ <gexp-input> (? self-quoting? x))
          (return x))
+        (($ <gexp-input> (? unspecified? x))
+         (return (quote x)))
         (($ <gexp-input> x)
          (raise (condition (&gexp-input-error (input x)))))
         (x
-- 
2.36.1