What version of Go are you using (go version)?

$ go version
go version go1.18 windows/amd64

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

$ go env
set GOARCH=amd64
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOVERSION=go1.18
set GCCGO=gccgo
set GOAMD64=v1

What did you do?

https://play.golang.com/p/PjD4wd90jdN

What did you expect to see?

path : /tmpfs/me/foo
-> dir : /tmpfs/me/
-> file: foo
-> base: foo
path : \users\me\foo.exe
-> dir : \users\me\
-> file: foo.exe
-> base: foo.exe
path : C:\users\me\foo.exe
-> dir : C:\users\me
-> file: foo.exe
-> base: foo.exe

What did you see instead?

path : /tmpfs/me/foo
-> dir : /tmpfs/me/
-> file: foo
-> base: foo
path : \users\me\foo.exe
-> dir :
-> file: \users\me\foo.exe
-> base: \users\me\foo.exe
path : C:\users\me\foo.exe
-> dir :
-> file: C:\users\me\foo.exe
-> base: C:\users\me\foo.exe