command_line: C:\mingw64\bin\g++.exe -ID:/a/btck/btck/include -isystem C:/vcpkg/installed/x64-mingw-static/include -O2 -std=gnu++20 -MD -MT test/cpp/CMakeFiles/btck.test.cpp.dir/block.cpp.obj -MF test\cpp\CMakeFiles\btck.test.cpp.dir\block.cpp.obj.d -o test/cpp/CMakeFiles/btck.test.cpp.dir/block.cpp.obj -c D:/a/btck/btck/test/cpp/block.cpp

working_directory: "D:/a/btck/btck/build"

Target: btck.test.cpp

Target Type: EXECUTABLE

Source: D:/a/btck/btck/test/cpp/block.cpp

Language: C++

Config: Release

stderr:

In file included from D:/a/btck/btck/test/cpp/block.cpp:8:

D:/a/btck/btck/include/btck/btck.hpp:488:7: warning: 'btck::Chain' has a field 'btck::Chain::impl_' whose type uses the anonymous namespace [-Wsubobject-linkage]

  488 | class Chain : public detail::range<Chain const>

      |       ^~~~~