(concat): Fix use of Fchar_bytes.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/fns.c b/src/fns.c
index 29ecef48712..d7bb5419f67 100644
--- a/src/fns.c
+++ b/src/fns.c
@@ -427,7 +427,7 @@ concat (nargs, args, target_type, last_special)
                 ch = XVECTOR (this)->contents[i];
                 if (! INTEGERP (ch))
                   wrong_type_argument (Qintegerp, ch);
-                leni += Fchar_bytes (ch);
+                leni += XFASTINT (Fchar_bytes (ch));
               }
           else
             for (; CONSP (this); this = XCONS (this)->cdr)
@@ -435,7 +435,7 @@ concat (nargs, args, target_type, last_special)
                 ch = XCONS (this)->car;
                 if (! INTEGERP (ch))
                   wrong_type_argument (Qintegerp, ch);
-                leni += Fchar_bytes (ch);
+                leni += XFASTINT (Fchar_bytes (ch));
               }
         }
       else