Downloading msys2 directly (not using the version in Rtools) and then installing GHCup with a pointer to the downloaded version of msys2 works, thanks for the tip. So the problem going forward is for everyone to agree on one version of msys2 instead of maintaining their own version! This is the way things used to be when there was only cygwin. On Tue, Feb 21, 2023 at 7:55 PM Dominick Samperi wrote:

Thanks Recursion,

I tried that, only installing GHCup and not MSYS and friends, then using Rtools version of MSYS, but this didn't work, perhaps because of a non-standard layout of the tools in Rtools.

FYI, placing Rtools\usr\bin in path (to get sh.exe and other Unix tools) breaks Haskell mode in emacs. When starting ghci with Ctrl-C Ctrol-L, it immediately terminates for no apparent reason. Removing Rtools from PATH fixes this problem!

When different apps like R, GHCup, Stack, Chocolatey, Cygwin, etc. all install different versions of MSYS, we are asking for trouble.

Dominick

On Tue, Feb 21, 2023 at 7:18 PM Eternal Recursion < eternal.recursion@proton.me> wrote:

...

HI Dominick!

It's been awhile since I discovered the proper incantations on Windoze, but what I remember is that installation went better if I already had Msys pre-installed, and simply told the ghcup installer where to find it (it asks at some point). I also found this helpful:

https://www.haskell.org/ghcup/guide/#troubleshooting

Specifically the section about certificate authority errors. Disabling curl and using wget is what I recall doing.

Sent with Proton Mail https://proton.me/ secure email.

------- Original Message ------- On Tuesday, February 21st, 2023 at 6:23 PM, Dominick Samperi < djsamperi@gmail.com> wrote:

I watched an interesting YouTube video explaining how to install and use the Haskell extension in VS code, but the information appears to be obsolete, because there is no mention of ghcup, and ghcup is now required, along with a new version of the Haskell extension (the old one is labeled "legacy").

Unfortunately, I could not install ghcup on Windows due to obscure PowerShell security issues, or missing libraries in MSYS. While wrestling with this problem I discovered that Unix tools from Rtools must not be in PATH while working with Stack, probably due to incompatible MSYS versions. But removing Rtools from PATH does not resolve the ghcup installation problems.

Any tips on ghcup installation under Windows would be appreciated.

Thanks, Dominick