https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71797
Bug ID: 71797 Summary: Spurious unused-variable warning with inline function and unrelated error Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: r at queiro dot co.uk Target Milestone: --- Created attachment 38854 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=38854&action=edit test case The unused-variable warning is only produced when another error is present and FOO_CONSTANT is initialized with an inline function. Otherwise, no warning is generated. Tested with g++ 4.8.4 and 4.9.3. ~ g++ -Wall foo.cc In file included from foo.cc:2:0: foo.h: In constructor ‘Foo::Foo()’: foo.h:8:13: error: ‘create_a_compile_error’ was not declared in this scope Foo() { create_a_compile_error; }; ^ foo.h: At global scope: foo.h:5:16: warning: ‘FOO_CONSTANT’ defined but not used [-Wunused-variable] const unsigned FOO_CONSTANT = f(4); ^ ~ g++ -v Using built-in specs. COLLECT_GCC=g++ COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.8/lto-wrapper Target: x86_64-linux-gnu Configured with: ../src/configure -v --with-pkgversion='Ubuntu 4.8.4-2ubuntu1~14.04.3' --with-bugurl=file:///usr/share/doc/gcc-4.8/README.Bugs --enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.8 --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.8 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object --disable-libmudflap --enable-plugin --with-system-zlib --disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64/jre --enable-java-home --with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64 --with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.8-amd64 --with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --enable-objc-gc --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --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 4.8.4 (Ubuntu 4.8.4-2ubuntu1~14.04.3) ~ cat foo.ii # 1 "foo.cc" # 1 "<built-in>" # 1 "<command-line>" # 1 "/usr/include/stdc-predef.h" 1 3 4 # 1 "<command-line>" 2 # 1 "foo.cc" static inline unsigned f(unsigned x) { return x; } const unsigned FOO_CONSTANT = f(4); class Foo { Foo() { create_a_compile_error; }; };