2 files changed, 13 insertions(+), 1 deletions(-)

M guix/gexp.scm
M tests/gexp.scm

@@ 685,7 685,8 @@ SUFFIX."
   expander => (lambda (obj lowered output)
                 (match obj
                   (($ <file-append> base suffix)
-                   (let* ((expand (lookup-expander base))
+                   (let* ((expand (or (lookup-expander base)
+                                      (lookup-expander lowered)))
                           (base   (expand base lowered output)))
                      (string-append base (string-concatenate suffix)))))))
 

@@ 441,6 441,17 @@
                   '(system-binding)))
             (x x)))))
 
+(test-assert "let-system in file-append"
+  (let ((mixed (file-append (let-system (system target)
+                              (if (not target) grep sed))
+                            "/bin"))
+        (grep  (file-append grep "/bin"))
+        (sed   (file-append sed "/bin")))
+    (and (equal? (gexp->sexp* #~(list #$mixed))
+                 (gexp->sexp* #~(list #$grep)))
+         (equal? (gexp->sexp* #~(list #$mixed) "powerpc64le-linux-gnu")
+                 (gexp->sexp* #~(list #$sed) "powerpc64le-linux-gnu")))))
+
 (test-assert "ungexp + ungexp-native"
   (let* ((exp    (gexp (list (ungexp-native %bootstrap-guile)
                              (ungexp coreutils)