diff --git a/src/restore.c b/src/restore.c
index 109f1770e..a7883a0a1 100644
--- a/src/restore.c
+++ b/src/restore.c
@@ -250,6 +250,7 @@ restobjchn(NHFILE *nhfp, boolean frozen)
             break;
 
         otmp = newobj();
+        assert(otmp != 0);
         restobj(nhfp, otmp);
         if (!first)
             first = otmp;
@@ -387,6 +388,7 @@ restmonchn(NHFILE *nhfp)
             break;
 
         mtmp = newmonst();
+        assert(mtmp != 0);
         restmon(nhfp, mtmp);
         if (!first)
             first = mtmp;