Re: Strange `file-name-sans-extension' behavior

[Richard Stallman]

    It means that to produce a full file name from a relative directory
    "c:" and a relative file name "bar", a function should yield
    "c:./bar".

Is this really relevant to file-name-sans-extension?
The directory it uses is the one that was in the argument file name.
If it was valid there, it should be equally valid in the result.
If it is not valid in the result, I guess it was not valid in
the argument.