On Fri, Jun 28, 2019 at 1:49 AM Stefan Monnier <monnier@iro.umontreal.ca>
wrote:

> So based on this discussion, I guess what this means is that using
> a plain `concat` can't be right: for Windows-style name "c:/foo/bar"
> we should use `(concat "file:///" file)`, whereas for POSIX-style file
> names "/foo/bar" we should use `(concat "file://" file)`.

Strictly speaking, I think POSIX /foo/bar pathnames should be stripped of
the initial slash and then concatenated...

...but yeah, you're right. We need to do different things.