Explicit error on changing case of negative integers

* src/casefiddle.c (casify_object): Reject negative integers:
Emacs characters are positive integers.  (Bug#25684)

diff --git a/src/casefiddle.c b/src/casefiddle.c
index b2b87e7a8581700d3740392926edaef79b3cf84c..11d594449166407c3b71a9e2ddcf21ca55b12a93 100644 (file)
--- a/src/casefiddle.c
+++ b/src/casefiddle.c
@@ -41,7 +41,7 @@ casify_object (enum case_action flag, Lisp_Object obj)
   if (NILP (XCHAR_TABLE (BVAR (current_buffer, downcase_table))->extras[1]))
     Fset_case_table (BVAR (current_buffer, downcase_table));
 
-  if (INTEGERP (obj))
+  if (NATNUMP (obj))
     {
       int flagbits = (CHAR_ALT | CHAR_SUPER | CHAR_HYPER
                      | CHAR_SHIFT | CHAR_CTL | CHAR_META);