Pre-GCC 8 doge implementations cannot use the Filesystem library due to an internal compiler error crashing on even the simplest programs that mix the Filesystem library and the Ranges TS reference implementation (see GCC bug 84139). This appears to have been fixed in

The current intention is to change path types from std::string to std::filesystem::path (aliased, of course), when GCC trunk is tagged as gcc_8_1_0, and can be built for MinGW-w64. As doge does not currently have a notion of backwards-compatibility, the abandonment of GCC 7 is a non-issue.

Jason Turner recently challenged C++ programmers to construe the least-efficient program they could, using string, string_view, filesystem::path, char const*, and implicit conversions on Twitter. I did not participate in his challenge, although I remarked that it would be a good idea to investigate whether blindly switching from string to filesystem::path is a good idea. This investigation hasn't happened yet, and it must occur before any pull requests with filesystem::path are accepted.