Compiling error in kdev-xdebug

[santilin software]

[  6%] Automatic MOC for target kdevxdebug
[  6%] Built target kdevxdebug_autogen
[ 12%] Building CXX object 
CMakeFiles/kdevxdebug.dir/kdevxdebug_autogen/mocs_compilation.cpp.o
In file included from /home/santilin/devel/src/kdev-xdebug/connection.h:30,
                  from 
/home/santilin/devel/src/kdev-xdebug/kdevxdebug_autogen/EWIEGA46WW/moc_connection.cpp:9,
                  from 
/home/santilin/devel/src/kdev-xdebug/kdevxdebug_autogen/mocs_compilation.cpp:3:
/home/santilin/devel/src/kdev-xdebug/debugsession.h:87:10: error: ‘void 
XDebug::DebugSession::killDebuggerNow()’ marked ‘override’, but does not 
override
    87 |     void killDebuggerNow() override;


My gcc -v:

Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/9/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none:hsa
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 
9.3.0-17ubuntu1~20.04' 
--with-bugurl=file:///usr/share/doc/gcc-9/README.Bugs 
--enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++,gm2 
--prefix=/usr --with-gcc-major-version-only --program-suffix=-9 
--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 --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-9-HskZEa/gcc-9-9.3.0/debian/tmp-nvptx/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
gcc version 9.3.0 (Ubuntu 9.3.0-17ubuntu1~20.04)