Bug#226952: gcc-3.3: -Wconversion is annoying

["David N. Welton" <davidw@debian.org>]

Package: gcc-3.3
Version: 1:3.3.2-4
Severity: minor


Hi,

Given the code:

#include <stdio.h>

void foo8(unsigned char);

void foo8(unsigned char q)
{
    printf("Quant8: 0x%X\n", q);
}


int main (void)
{
    int i;

    i = 0x12;
    foo8( (unsigned char)i );
    return 0;
}

Compiling it like so:

@ashland [~/tmp] $ gcc -o tst tst.c -Wconversion
tst.c: In function `main':
tst.c:16: warning: passing arg 1 of `foo8' with different width due
to prototype

Despite this being perfectly valid C code!  I guess someone might want
that for some odd reason, however, -Wconversion also does something
useful:

     Also, warn if a negative integer constant expression is
     implicitly converted to an unsigned type.  For example, warn
     about the assignment `x = -1' if `x' is unsigned.  But do not
     warn about explicit casts like `(unsigned) -1'.

This is actually helpful.  It would be nice if gcc could do the above
via a separate -W..... flag and leave:

`-Wconversion'
     Warn if a prototype causes a type conversion that is different
     from what would happen to the same argument in the absence of a
     prototype.  This includes conversions of fixed point to floating
     and vice versa, and conversions changing the width or signedness
     of a fixed point argument except when the same as the default
     promotion.

to whoever needs such an odd warning.

Thanks for your time,
Dave

-- System Information:
Debian Release: testing/unstable
Architecture: powerpc
Kernel: Linux ashland 2.4.24 #2 Mon Jan 5 19:10:49 CET 2004 ppc
Locale: LANG=en_US, LC_CTYPE=en_US

Versions of packages gcc-3.3 depends on:
ii  binutils                   2.14.90.0.7-3 The GNU assembler, linker and bina
ii  cpp-3.3                    1:3.3.2-4     The GNU C preprocessor
ii  gcc-3.3-base               1:3.3.2-4     The GNU Compiler Collection (base 
ii  libc6                      2.3.2.ds1-10  GNU C Library: Shared libraries an
ii  libgcc1                    1:3.3.2-4     GCC support library

-- no debconf information