What is std::filesystem::remove_all() supposed to do with an empty path?

I wonder, what is supposed to happen with a call such as this?

#include <filesystem>

int main() {
    std::filesystem::remove_all({});
    return 0;
}

I guess path::empty() implies that my argument is an empty path, but this page does not have anything that I recognize as useful regarding empty paths.

Normal form of an empty path is an empty path. It is represented by "" (empty string) in the literal sense. And an empty path doesn’t exist as a real path on the filesystem of the OS. You can test this with:

std::filesystem::exists(std::filesystem::path{}); /* <—- will return false */

The program code in the OP

#include <filesystem>

int main() {
    std::filesystem::remove_all({});
    return 0;
}

Will therefore be expected to behave according to the specification in the standard:

Remove all

uintmax_t remove_all(const path& p);

uintmax_t remove_all(const path& p, error_code& ec);

1. Effects: Recursively deletes the contents of p if it exists, then deletes file p itself, as if by POSIX remove(). [Note: A symbolic link is itself removed, rather than the file it resolves to. —end note]

2. Postconditions: exists(symlink_status(p)) is false.

3. Returns: The number of files removed. The signature with argument ec returns static_cast<uintmax_t>(-1) if an error occurs.

—-ISO/IEC JTC1 SC22 WG21 N4860 29.11.14.31

Since std::filesystem::path{} doesn’t exist on the OS, the return value of

std::filesystem::remove_all({});

Will be 0. No files will be removed.