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Date: Tue, 21 Apr 2009 21:46:00 -0000
Subject: [Bug c/39841]  New: -Wall on 'signed char' array subscript
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I appreciate the fact that gcc is able to warn about misuse of <ctype.h> macros
when they are written as an array access, when the programmer mistakenly uses
'char' (under -fsigned-char) instead of the standard-mandated int containing an
unsigned char value (there is discussion right now on the newlib list about
rewriting isalpha and friends in a manner more conducive to triggering this
warning, http://sourceware.org/ml/newlib/2009/msg00511.html).

However, I expected that gcc would also warn about 'signed char':

$ cat foo.c
signed char ch;
int array[1];
int main ()
{
  return array[ch];
}
$ gcc -Wall -c -o foo.o foo.c -Dsigned=
foo.c: In function 'main':
foo.c:5: warning: array subscript has type 'char'
$ gcc -Wall -c -o foo.o foo.c
$


-- 
           Summary: -Wall on 'signed char' array subscript
           Product: gcc
           Version: 4.3.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: ebb9 at byu dot net


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39841