From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 27970 invoked by alias); 4 Apr 2014 14:30:03 -0000 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org Received: (qmail 27557 invoked by uid 48); 4 Apr 2014 14:29:56 -0000 From: "giuliano.procida at googlemail dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug c/60759] New: -Wlogical-op should perhaps warn about two-way implicit conversions Date: Fri, 04 Apr 2014 14:30:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: c X-Bugzilla-Version: 4.6.3 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: giuliano.procida at googlemail dot com X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version bug_status bug_severity priority component assigned_to reporter Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2014-04/txt/msg00309.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60759 Bug ID: 60759 Summary: -Wlogical-op should perhaps warn about two-way implicit conversions Product: gcc Version: 4.6.3 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c Assignee: unassigned at gcc dot gnu.org Reporter: giuliano.procida at googlemail dot com Expressions of the form "a && b" or "a || b" that involve both implicit bool->integer and implicit integer->bool coercion, represent a probable misuse of a logical operator. These should perhaps generate warnings, particularly for C++ code: int foo(int x); int a = foo(1) || foo(2); // Confusion with Perl, Python behaviour, int one = 2 && 3; // or perhaps bitwise operation was intended. These should not probably generate warnings: while (foo(1) || foo(2)); int zero = (1 != 2) && (3 == 4); Example: $ gcc -v Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.6/lto-wrapper Target: x86_64-linux-gnu Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro 4.6.3-1ubuntu5' --with-bugurl=file:///usr/share/doc/gcc-4.6/README.Bugs --enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.6 --enable-shared --enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.6 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object --enable-plugin --enable-objc-gc --disable-werror --with-arch-32=i686 --with-tune=generic --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu Thread model: posix gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5) $ cat foo.c static int x = 2 || 3; int main() { return x; } $ gcc -Wall -Wextra -Wlogical-op foo.c $ g++ -Wall -Wextra -Wlogical-op foo.c [no warnings]