> It does.

It works in Cygwin right now, it doesn't work on Win32 without a compatibility layer. Personally, I don't think of that as "working on Windows", but I concede that that's somewhat up to interpretation on the "on Windows" part. I'm confident that someone is going to get a MingW build working even if it's not official.

> With Go, it would have worked out of the box on all the targets Go can support.

That's absolutely disingenious. If you choose to only use the Go standard library , sure. But the same is true for Rust and even for C++. If you don't use any platform-specific APIs most languages will work on any target. Fish, however, does use platform-specific APIs and nothing about Go changes that.

unless you have to deal with OS specific APIs around process management and tty input, which is the bulk of what makes a shell challenging to implement

As long as you called no platform specific APIs. The same is true of Rust and many (even most) languages. Go isn't magic here.