https://gcc.godbolt.org/z/iH643m Is this intentional? No other compiler that I know warns this code. % cat tmp.cc [[deprecated(">>>GCC BUG<<<")]] void func(void) { typedef int type; type(var); } % g++-10 -v -c tmp.cc Using built-in specs. COLLECT_GCC=g++-10 OFFLOAD_TARGET_NAMES=nvptx-none:amdgcn-amdhsa:hsa OFFLOAD_TARGET_DEFAULT=1 Target: x86_64-linux-gnu Configured with: ../src/configure -v --with-pkgversion='Ubuntu 10.1.0-2ubuntu1~18.04' --with-bugurl=file:///usr/share/doc/gcc-10/README.Bugs --enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++,m2 --prefix=/usr --with-gcc-major-version-only --program-suffix=-10 --program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-vtable-verify --enable-plugin --enable-default-pie --with-system-zlib --enable-libphobos-checking=release --with-target-system-zlib=auto --enable-objc-gc=auto --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic --enable-offload-targets=nvptx-none=/build/gcc-10-eDoCEC/gcc-10-10.1.0/debian/tmp-nvptx/usr,amdgcn-amdhsa=/build/gcc-10-eDoCEC/gcc-10-10.1.0/debian/tmp-gcn/usr,hsa --without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu Thread model: posix Supported LTO compression algorithms: zlib zstd gcc version 10.1.0 (Ubuntu 10.1.0-2ubuntu1~18.04) COLLECT_GCC_OPTIONS='-v' '-c' '-shared-libgcc' '-mtune=generic' '-march=x86-64' /usr/lib/gcc/x86_64-linux-gnu/10/cc1plus -quiet -v -imultiarch x86_64-linux-gnu -D_GNU_SOURCE tmp.cc -quiet -dumpbase tmp.cc -mtune=generic -march=x86-64 -auxbase tmp -version -fasynchronous-unwind-tables -fstack-protector-strong -Wformat -Wformat-security -o /tmp/ccz4O9iB.s GNU C++14 (Ubuntu 10.1.0-2ubuntu1~18.04) version 10.1.0 (x86_64-linux-gnu) compiled by GNU C version 10.1.0, GMP version 6.1.2, MPFR version 4.0.1, MPC version 1.1.0, isl version isl-0.19-GMP GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072 ignoring duplicate directory "/usr/include/x86_64-linux-gnu/c++/10" ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu" ignoring nonexistent directory "/usr/lib/gcc/x86_64-linux-gnu/10/include-fixed" ignoring nonexistent directory "/usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include" #include "..." search starts here: #include <...> search starts here: /usr/include/c++/10 /usr/include/x86_64-linux-gnu/c++/10 /usr/include/c++/10/backward /usr/lib/gcc/x86_64-linux-gnu/10/include /usr/local/include /usr/include/x86_64-linux-gnu /usr/include End of search list. GNU C++14 (Ubuntu 10.1.0-2ubuntu1~18.04) version 10.1.0 (x86_64-linux-gnu) compiled by GNU C version 10.1.0, GMP version 6.1.2, MPFR version 4.0.1, MPC version 1.1.0, isl version isl-0.19-GMP GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072 Compiler executable checksum: 435c9a72f92ce04eba08a47828fa63c4 tmp.cc: In function 'void func()': tmp.cc:5:13: warning: 'void func()' is deprecated: >>>GCC BUG<<< [-Wdeprecated-declarations] 5 | type(var); | ^ tmp.cc:2:6: note: declared here 2 | void func(void) | ^~~~ COLLECT_GCC_OPTIONS='-v' '-c' '-shared-libgcc' '-mtune=generic' '-march=x86-64' as -v --64 -o tmp.o /tmp/ccz4O9iB.s GNU assembler version 2.30 (x86_64-linux-gnu) using BFD version (GNU Binutils for Ubuntu) 2.30 COMPILER_PATH=/usr/lib/gcc/x86_64-linux-gnu/10/:/usr/lib/gcc/x86_64-linux-gnu/10/:/usr/lib/gcc/x86_64-linux-gnu/:/usr/lib/gcc/x86_64-linux-gnu/10/:/usr/lib/gcc/x86_64-linux-gnu/ LIBRARY_PATH=/usr/lib/gcc/x86_64-linux-gnu/10/:/usr/lib/gcc/x86_64-linux-gnu/10/../../../x86_64-linux-gnu/:/usr/lib/gcc/x86_64-linux-gnu/10/../../../../lib/:/lib/x86_64-linux-gnu/:/lib/../lib/:/usr/lib/x86_64-linux-gnu/:/usr/lib/../lib/:/usr/lib/gcc/x86_64-linux-gnu/10/../../../:/lib/:/usr/lib/ COLLECT_GCC_OPTIONS='-v' '-c' '-shared-libgcc' '-mtune=generic' '-march=x86-64'
Shyouhei, thank you for filing this ticket. I agree that GCC should not complain about deprecated usage if the symbol is not really used. Such GCC behavior causes excessive compile time warnings when using SWIG library https://github.com/swig/swig/issues/1689#issuecomment-636109918
The same problem happens with a namespace alias: namespace foo { void bar(); } [[deprecated("zed")]] inline void zed() { namespace a = foo; a::bar(); } Produces: test.cc: In function ‘void zed()’: test.cc:6:8: warning: ‘void zed()’ is deprecated: zed [-Wdeprecated-declarations] 6 | a::bar(); | ^~~ test.cc:4:35: note: declared here 4 | [[deprecated("zed")]] inline void zed() { | ^~~ If instead of the alias foo::bar() is used directly, no warning is produced. The issue is still present on current master (346bce6fe0cf1ed5f6a7ad732d2361d77b203c87).
Seems fixed in GCC 10.3.0 and 11+.
Dup of bug 99318. *** This bug has been marked as a duplicate of bug 99318 ***
Confirmed fixed at GCC 10.3.0. Thank you!