1 files changed, 4 insertions, 2 deletions

diff --git a/src/fns.c b/src/fns.c
index dabd05ab2cf..421879fde9f 100644
--- a/src/fns.c
+++ b/src/fns.c
@@ -1995,9 +1995,11 @@ mapcar1 (leni, vals, fn, seq)
       for (i = 0, i_byte = 0; i < leni;)
         {
           int c;
-          FETCH_STRING_CHAR_ADVANCE (c, seq, i, i_byte)
+          int i_before = i;
+
+          FETCH_STRING_CHAR_ADVANCE (c, seq, i, i_byte);
           XSETFASTINT (dummy, c);
-          vals[i] = call1 (fn, dummy);
+          vals[i_before] = call1 (fn, dummy);
         }
     }
   else   /* Must be a list, since Flength did not get an error */