diff --git a/src/worn.c b/src/worn.c
index 92299d3ca..1040715e4 100644
--- a/src/worn.c
+++ b/src/worn.c
@@ -1,4 +1,4 @@
-/* NetHack 3.7	worn.c	$NHDT-Date: 1646260985 2022/03/02 22:43:05 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.81 $ */
+/* NetHack 3.7	worn.c	$NHDT-Date: 1649529637 2022/04/09 18:40:37 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.82 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /*-Copyright (c) Robert Patrick Rankin, 2013. */
 /* NetHack may be freely redistributed.  See license for details. */
@@ -58,7 +58,7 @@ setworn(struct obj *obj, long mask)
             if (wp->w_mask & mask) {
                 oobj = *(wp->w_obj);
                 if (oobj && !(oobj->owornmask & wp->w_mask))
-                    impossible("Setworn: mask = %ld.", wp->w_mask);
+                    impossible("Setworn: mask=0x%08lx.", wp->w_mask);
                 if (oobj) {
                     if (u.twoweap && (oobj->owornmask & (W_WEP | W_SWAPWEP)))
                         set_twoweap(FALSE); /* u.twoweap = FALSE */