1 files changed, 3 insertions, 1 deletions

diff --git a/src/alloc.c b/src/alloc.c
index fc8787670e6..7a1d488c6a0 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -3600,7 +3600,9 @@ Garbage collection happens automatically if you cons more than\n\
     for (i = 0; i < tail->nvars; i++)
       if (!XMARKBIT (tail->var[i]))
         {
-          mark_object (&tail->var[i]);
+          /* Explicit casting prevents compiler warning about
+             discarding the `volatile' qualifier.  */
+          mark_object ((Lisp_Object *)&tail->var[i]);
           XMARK (tail->var[i]);
         }
 #endif