diff --git a/lisp/net/rcirc.el b/lisp/net/rcirc.el
index 4d98d65d58a..d4f0ccd47cd 100644
--- a/lisp/net/rcirc.el
+++ b/lisp/net/rcirc.el
@@ -2403,12 +2403,12 @@ that, an interactive form can specified."
                    (insert "\\`")
                    (when arguments
                      (dotimes (_ (1- (length arguments)))
-                       (insert "\\(?:\\(.+?\\)"))
-                     (insert "\\(?:[[:space:]]+\\(.*\\)\\)")
+                       (insert "\\(?:\\(.+?\\)[[:space:]]+"))
                      (dotimes (i (1- (length arguments)))
-                       (when (< i optional)
-                         (insert "?"))
-                       (insert "\\)")))
+                       (if (< i optional)
+                           (insert "\\)?")
+                         (insert "\\)"))))
+                   (insert "\\(.*?\\)")
                    (insert "[[:space:]]*\\'")
                    (buffer-string)))
          (argument (gensym))