diff --git a/scsh/rx/parse.scm b/scsh/rx/parse.scm
index 89cc5b6..985e91c 100644
--- a/scsh/rx/parse.scm
+++ b/scsh/rx/parse.scm
@@ -273,7 +273,7 @@
 				      cs1)
 				 . ,(if (char-set? cs2)
 					(list (char-set->scheme cs2 r))
-					(cdr cs2))))))
+					(list cs2))))))
 		  (if cset? cs (make-re-char-set cs)))
 		(error "SRE set-difference operator (- ...) requires at least one argument")))