path::extension() of parent directory

[chan-lee]

Describe the bug
extension of a path ending in parent directory returns "."

To Reproduce
CHECK(fs::path("/foo/..").extension() == ".");

Expected behavior
but reference site is different ( https://en.cppreference.com/w/cpp/filesystem/path/extension )
CHECK(fs::path("/foo/..").extension() == "");

Additional context
nothing

[gulrak]

Yeah, you are right, that should not be.