otherwise would `numpy @ https://example.org/numpy` is not a valid specifier (missing whitespace after the URL). This already what pip and packaging do and also what the parsley grammar says

Otherwise `numpy; os_namein 'posix'` would be a valid specifier which it isn't

Otherwise `numpy; os_name in'posix'` and `numpy; os_name inos_name` would be valid. pypa/packaging 22.0 actually allows currently `numpy; os_name in'posix'`