1 files changed, 6 insertions, 0 deletions

diff --git a/src/casefiddle.c b/src/casefiddle.c
index ae60d2c8dd5..6387c4bc845 100644
--- a/src/casefiddle.c
+++ b/src/casefiddle.c
@@ -52,6 +52,12 @@ casify_object (flag, obj)
                           | CHAR_SHIFT | CHAR_CTL | CHAR_META);
           int flags = XINT (obj) & flagbits;
 
+          /* If the character has higher bits set
+             above the flags, return it unchanged.
+             It is not a real character.  */
+          if ((unsigned) XFASTINT (obj) > (unsigned) flagbits)
+            return obj;
+
           c = DOWNCASE (XFASTINT (obj) & ~flagbits);
           if (inword)
             XSETFASTINT (obj, c | flags);