(Fstring_as_unibyte): Set size_byte field to -1.

diff --git a/src/fns.c b/src/fns.c
index c98cb2547b8355675dd1b6c5d8f4e45519992310..7bd7c5b613a71a2c594ec0e5343f8dd26b6602af 100644 (file)
--- a/src/fns.c
+++ b/src/fns.c
@@ -858,6 +858,7 @@ If STRING is unibyte, the result is STRING itself.")
     {
       string = Fcopy_sequence (string);
       XSTRING (string)->size = STRING_BYTES (XSTRING (string));
+      SET_STRING_BYTES (XSTRING (string), -1);
     }
   return string;
 }