diff --git a/src/misc.ml b/src/misc.ml
index 20b64c9c1b98998e7c34886c90d5e31156ca6305..92ac9abd7b50d2269662f37214bdaaf268dff55e 100644
--- a/src/misc.ml
+++ b/src/misc.ml
@@ -230,7 +230,7 @@ let rec smapa f accu = function
 
 let normalize s =
   let s = Bytes.of_string s in
-  let n = String.length s in
+  let n = Bytes.length s in
   for i = 0 to n - 1 do
     match Bytes.get s i with
     | '('