1 files changed, 4 insertions, 1 deletions

diff --git a/src/casefiddle.c b/src/casefiddle.c
index 9545cf697a8..b6551618b2f 100644
--- a/src/casefiddle.c
+++ b/src/casefiddle.c
@@ -221,6 +221,8 @@ casify_region (enum case_action flag, Lisp_Object b, Lisp_Object e)
   start_byte = CHAR_TO_BYTE (start);
   end_byte = CHAR_TO_BYTE (end);
 
+  SETUP_BUFFER_SYNTAX_TABLE();  /* For syntax_prefix_flag_p.  */
+
   while (start < end)
     {
       int c2, len;
@@ -243,7 +245,8 @@ casify_region (enum case_action flag, Lisp_Object b, Lisp_Object e)
                && (!inword || flag != CASE_CAPITALIZE_UP))
         c = UPCASE1 (c);
       if ((int) flag >= (int) CASE_CAPITALIZE)
-        inword = ((SYNTAX (c) == Sword) && (inword || !SYNTAX_PREFIX (c)));
+        inword = ((SYNTAX (c) == Sword)
+                  && (inword || !syntax_prefix_flag_p (c)));
       if (c != c2)
         {
           last = start;