reproduce (this is a W=1 build):
        git remote add xiang-erofs https://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs.git
        git fetch xiang-erofs dev-test
        git checkout xiang-erofs/dev-test
        b4 shazam https://lore.kernel.org/r/20251127073122.2542542-4-hsiangkao@linux.alibaba.com
        # apt-get install sparse
        # sparse version: v0.6.4-71-g610d841d

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=x86_64 olddefconfig
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=x86_64 SHELL=/bin/bash fs/erofs/