(CHAR_TABLE_REF): Check if IDX is negative or not.

diff --git a/src/lisp.h b/src/lisp.h
index 7f83269c88e42514e14560dac6151df0a30bd19c..9b533f528ed3afe4b97aa6fe9cd5d674ff7086ab 100644 (file)
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -641,7 +641,7 @@ struct Lisp_Vector
    and 8-bit Europeans characters.  For these characters, do not check
    validity of CT.  Do not follow parent.  */
 #define CHAR_TABLE_REF(CT, IDX)                                \
-  ((IDX) < CHAR_TABLE_SINGLE_BYTE_SLOTS                        \
+  ((IDX) >= 0 && (IDX) < CHAR_TABLE_SINGLE_BYTE_SLOTS  \
    ? (!NILP (XCHAR_TABLE (CT)->contents[IDX])          \
       ? XCHAR_TABLE (CT)->contents[IDX]                        \
       : XCHAR_TABLE (CT)->defalt)                      \