diff --git a/scsh/rx/re.scm b/scsh/rx/re.scm
index b06227e..eef6633 100644
--- a/scsh/rx/re.scm
+++ b/scsh/rx/re.scm
@@ -133,14 +133,16 @@
   (really-make-re-choice elts tsm (new-cre posix-str tvec)))
 
 (define (make-re-choice res)
-  (make-re-choice/tsm res
-		      (fold (lambda (re sm-count)
-			   (let ((maybe-tsm (re-tsm re)))
-			     (if (and (number? maybe-tsm)
-				      (number? sm-count))
-				 (+ maybe-tsm sm-count)
-				 (unspecific))))
-			    0 res)))
+  (if (every re-char-set? res)
+      (make-re-char-set (apply char-set-union (map re-char-set:cset res)))
+      (make-re-choice/tsm res
+                          (fold (lambda (re sm-count)
+                                  (let ((maybe-tsm (re-tsm re)))
+                                    (if (and (number? maybe-tsm)
+                                             (number? sm-count))
+                                        (+ maybe-tsm sm-count)
+                                        (unspecific))))
+                                0 res))))
 
 ;;; Slightly smart choice constructor:
 ;;; - Flattens nested choices