diff --git a/guix/build-system/gnu.scm b/guix/build-system/gnu.scm
index 86c49a6d6ed76baf6b066ca9693339d5b7f4f940..0998e6f21b72277016edf06684b0d46ec0c4e339 100644
--- a/guix/build-system/gnu.scm
+++ b/guix/build-system/gnu.scm
@@ -395,7 +395,7 @@ (define %build-target-inputs
                                       drv-path sub)))
                    ((name path)
                     `(,name . ,path)))
-                  (append (or implicit-target-inputs) inputs)))
+                  (append (or implicit-target-inputs '()) inputs)))
 
          (gnu-build #:source ,(if (and source (derivation-path? source))
                                   (derivation-path->output-path source)