Trying to set up a new cabal project with relude, but it doesn’t work for some reason:

exodrifter@rain ~/w/e/catbox> cabal run
Resolving dependencies...
Error: cabal: Could not resolve dependencies:
[__0] trying: catbox-0.1.0.0 (user goal)
[__1] next goal: base (dependency of catbox)
[__1] rejecting: base-4.17.2.1/installed-4.17.2.1 (conflict: catbox =>
base>=4.14 && <4.17)
[__1] skipping: base-4.20.0.1, base-4.20.0.0, base-4.19.1.0, base-4.19.0.0,
base-4.18.2.1, base-4.18.2.0, base-4.18.1.0, base-4.18.0.0, base-4.17.2.1,
base-4.17.2.0, base-4.17.1.0, base-4.17.0.0 (has the same characteristics that
caused the previous version to fail: excluded by constraint '>=4.14 && <4.17'
from 'catbox')
[__1] rejecting: base-4.16.4.0, base-4.16.3.0, base-4.16.2.0, base-4.16.1.0,
base-4.16.0.0, base-4.15.1.0, base-4.15.0.0, base-4.14.3.0, base-4.14.2.0,
base-4.14.1.0, base-4.14.0.0, base-4.13.0.0, base-4.12.0.0, base-4.11.1.0,
base-4.11.0.0, base-4.10.1.0, base-4.10.0.0, base-4.9.1.0, base-4.9.0.0,
base-4.8.2.0, base-4.8.1.0, base-4.8.0.0, base-4.7.0.2, base-4.7.0.1,
base-4.7.0.0, base-4.6.0.1, base-4.6.0.0, base-4.5.1.0, base-4.5.0.0,
base-4.4.1.0, base-4.4.0.0, base-4.3.1.0, base-4.3.0.0, base-4.2.0.2,
base-4.2.0.1, base-4.2.0.0, base-4.1.0.0, base-4.0.0.0, base-3.0.3.2,
base-3.0.3.1 (constraint from non-upgradeable package requires installed
instance)
[__1] fail (backjumping, conflict set: base, catbox)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: base, catbox

I’m confused, because I would expect cabal to download whatever the right version of a library is for the build. However, after some research, that’s apparently not how it works for base.

danidiaz:

Your version of the base library is 4.15.0.0. base is special in the sense that its version is tied to your GHC version, which seems to be GHC 9.0.1.

So, unlike with other libraries, cabal can’t simply install a previous version of base when it’s required by the build-depends: of some package. So, in order for the compilation to work i need to downgrade the version of ghc installed on my system. I manage my ghc installation with ghcup, so I can pick a different ghc version with ghcup tui.