[Bug c/57531] New: lvalue required with comma operator

[vijunag at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57531

            Bug ID: 57531
           Summary: lvalue required with comma operator
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vijunag at gmail dot com

Following expression cannot be compiled using gcc-4.7.2 where as the same
statement is perfectly acceptable by gcc version 4.4.5
 (void) 0, a = b;

[vinag]$ ~/tools/bintools/linux-x86/gcc/201302221200/bin/i686-pc-linux-gnu-gcc
-v
Using built-in specs.
COLLECT_GCC=~/tools/bintools/linux-x86/gcc/201302221200/bin/i686-pc-linux-gnu-gcc-wrapped
COLLECT_LTO_WRAPPER=~/tools/bintools/linux-x86/gcc/201302221200/libexec/gcc/i686-pc-linux-gnu/4.7.2/lto-wrapper
Target: i686-pc-linux-gnu
Configured with: ../../gcc/configure --build=amd64-pc-linux-gnu
--host=amd64-pc-linux-gnu --target=i686-pc-linux-gnu --enable-languages=c,c++
--prefix=/ws/vinag-bgl/tools/bintools/linux-x86/gcc/201302221200
--enable-shared --with-headers=/tmp/201302221200/new_header/
--disable-libquadmath --disable-libgomp --disable-libssp --disable-libmudflap
--disable-libitm --with-fast-fixincludes --enable-threads --site=starent
--with-gnu-as --with-gnu-ld
Thread model: posix
gcc version 4.7.2 (GCC) 

Program:

vijay:/home/vijay]$ cat ternary.c

#include <stdio.h>

int main()
{
  int a;
  (void )0, a = 4;
}
[vijay]i686-pc-linux-gnu-gcc lvalue.cpp -c
lvalue.cpp: In function ‘void lvalue_assignment()’:
lvalue.cpp:6:27: error: lvalue required as left operand of assignment

vijay:/home/vijay]$ gcc ternary.c -o ternary.c.out
vijay:/home/vijay]$ gcc -v
Using built-in specs.
Target: i686-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro
4.4.4-14ubuntu5' --with-bugurl=file:///usr/share/doc/gcc-4.4/README.Bugs
--enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-4.4 --enable-shared --enable-multiarch
--enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib
--without-included-gettext --enable-threads=posix
--with-gxx-include-dir=/usr/include/c++/4.4 --libdir=/usr/lib --enable-nls
--with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-objc-gc
--enable-targets=all --disable-werror --with-arch-32=i686 --with-tune=generic
--enable-checking=release --build=i686-linux-gnu --host=i686-linux-gnu
--target=i686-linux-gnu
Thread model: posix
gcc version 4.4.5 (Ubuntu/Linaro 4.4.4-14ubuntu5)