https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71394
Bug ID: 71394 Summary: -Werror=conversion-null identifies incorrect data member of member initializer list Product: gcc Version: 4.8.2 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: mitchjcarlson at gmail dot com Target Milestone: --- Created attachment 38632 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=38632&action=edit preprocessed file In the below example, we can see that the error message produced from the compiler incorrectly identifies a data member which is in violation of our Werror. The current error message is misleading. #include <cstddef> struct ErrorConversionNullBug { ErrorConversionNullBug() : n(NULL) , c('c') {} unsigned int n; const char c; }; int main() { ErrorConversionNullBug bug; } $ /opt/gcc/4.8.2/bin/g++48 -v -save-temps -Werror=conversion-null -o main main.cpp Using built-in specs. COLLECT_GCC=/opt/gcc/4.8.2/bin/g++48 COLLECT_LTO_WRAPPER=/opt/gcc/4.8.2/libexec/gcc/i686-pc-linux-gnu/4.8.2/lto-wrapper Target: i686-pc-linux-gnu Configured with: ./configure --prefix=/opt/gcc/4.8.2 --enable-languages=c,c++ --program-suffix=48 --with-as=/opt/binutils/2.24/bin/as24 --with-ld=/opt/binutils/2.24/bin/ld24 Thread model: posix gcc version 4.8.2 (GCC) COLLECT_GCC_OPTIONS='-v' '-save-temps' '-Werror=conversion-null' '-o' 'main' '-shared-libgcc' '-mtune=generic' '-march=pentiumpro' /opt/gcc/4.8.2/libexec/gcc/i686-pc-linux-gnu/4.8.2/cc1plus -E -quiet -v -D_GNU_SOURCE main.cpp -mtune=generic -march=pentiumpro -Werror=conversion-null -fpch-preprocess -o main.ii ignoring nonexistent directory "/opt/gcc/4.8.2/lib/gcc/i686-pc-linux-gnu/4.8.2/../../../../i686-pc-linux-gnu/include" #include "..." search starts here: #include <...> search starts here: /opt/gcc/4.8.2/lib/gcc/i686-pc-linux-gnu/4.8.2/../../../../include/c++/4.8.2 /opt/gcc/4.8.2/lib/gcc/i686-pc-linux-gnu/4.8.2/../../../../include/c++/4.8.2/i686-pc-linux-gnu /opt/gcc/4.8.2/lib/gcc/i686-pc-linux-gnu/4.8.2/../../../../include/c++/4.8.2/backward /opt/gcc/4.8.2/lib/gcc/i686-pc-linux-gnu/4.8.2/include /usr/local/include /opt/gcc/4.8.2/include /opt/gcc/4.8.2/lib/gcc/i686-pc-linux-gnu/4.8.2/include-fixed /usr/include End of search list. COLLECT_GCC_OPTIONS='-v' '-save-temps' '-Werror=conversion-null' '-o' 'main' '-shared-libgcc' '-mtune=generic' '-march=pentiumpro' /opt/gcc/4.8.2/libexec/gcc/i686-pc-linux-gnu/4.8.2/cc1plus -fpreprocessed main.ii -quiet -dumpbase main.cpp -mtune=generic -march=pentiumpro -auxbase main -Werror=conversion-null -version -o main.s GNU C++ (GCC) version 4.8.2 (i686-pc-linux-gnu) compiled by GNU C version 4.8.2, GMP version 5.1.1, MPFR version 3.1.1, MPC version 1.0.1 GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072 GNU C++ (GCC) version 4.8.2 (i686-pc-linux-gnu) compiled by GNU C version 4.8.2, GMP version 5.1.1, MPFR version 3.1.1, MPC version 1.0.1 GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072 Compiler executable checksum: 966073129663909613ddef5561ea5ee6 main.cpp: In constructor 'ErrorConversionNullBug::ErrorConversionNullBug()': main.cpp:7:16: error: converting to non-pointer type 'unsigned int' from NULL [-Werror=conversion-null] , c('c') ^ cc1plus: some warnings being treated as errors $ lscpu Architecture: i686 CPU op-mode(s): 32-bit, 64-bit Byte Order: Little Endian CPU(s): 0 Vendor ID: GenuineIntel CPU family: 6 Model: 63 Stepping: 2 CPU MHz: 2600.007 BogoMIPS: 5199.24 Virtualization: VT-x $ cat /proc/version Linux version 2.6.32-573.8.1.el6.x86_64 (mockbu...@c6b8.bsys.dev.centos.org) (gcc version 4.4.7 20120313 (Red Hat 4.4.7-16) (GCC) ) #1 SMP Tue Nov 10 18:01:38 UTC 2015