[Haskell-cafe] Cabal problem, broken packages?

[Tom Ellis]

On Thu, Sep 15, 2022 at 05:23:10PM +0200, Volker Wysk wrote:
> I've lately set up the Haskell environment on my Linux box, with no
> problems. Then I have installed some packages with "cabal install", again
> without problems. But now I'm trying to install another package and I get a
> dependency conflict. It doesn't seem to matter which package I try to
> install:

This is quite weird, because neither directory nor ghc are
dependencies of rfc5051.

As a first step, can you try the following and report back whether you
successfully get to a GHCi a prompt?

$ cabal repl -z --build-depends rfc5051

> desktop ~ $ cabal install rfc5051
> Resolving dependencies...
> cabal: Could not resolve dependencies:
> [__0] next goal: directory (user goal)
> [__0] rejecting: directory-1.3.8.0 (constraint from user target requires
> ==1.3.7.1)
> [__0] trying: directory-1.3.7.1
> [__1] next goal: ghc (user goal)
> [__1] rejecting: ghc-9.4.2, ghc-9.4.1, ghc-9.2.4, ghc-9.2.3, ghc-9.2.2,
> ghc-9.2.1, ghc-9.0.2, ghc-8.10.7, ghc-8.10.2, ghc-8.10.1 (constraint from
> user
> target requires ==8.8.4)
> [__1] rejecting: ghc-8.8.4/installed-8.8... (conflict: directory==1.3.7.1,
> ghc
> => directory==1.3.6.0/installed-1.3...)
> [__1] rejecting: ghc-8.8.3, ghc-8.8.1, ghc-8.6.5, ghc-8.6.4, ghc-8.6.1,
> ghc-8.4.4, ghc-8.4.3, ghc-8.4.1, ghc-8.2.2, ghc-8.2.1, ghc-9.2.3.20220620
> (constraint from user target requires ==8.8.4)
> [__1] fail (backjumping, conflict set: directory, ghc)
> After searching the rest of the dependency tree exhaustively, these were the
> goals I've had most trouble fulfilling: directory, ghc