Cabal version too high. Did you have a pre existing cabal installation independent of stack or something?
Re:An opinionated guide to Haskell
by resoluteteeth on Saturday February 10, 2018 @04:02PM
(#16349562)
I don't think that I do. Is it possible that ghc-mod is broken on lts-10.5?
Re:An opinionated guide to Haskell
by lexi-lambda on Saturday February 10, 2018 @04:39PM
(#16349756)
It isn’t broken in lts-10.5, it just isn’t in lts-10 at all. Go to https://www.stackage.org/lts-10.5 and search for ghc-mod—it just isn’t currently available.
Unfortunately, the reason for this is that ghc-mod still isn’t updated for GHC 8.2. It’s almost there—a package candidate has been uploaded that works alright—but it hasn’t made it into the LTS yet. There’s a way to build and install the package candidate in a way that will work with stack, which I have done on my personal machine, but honestly I decided it was just too much for this (already overly long) blog post.
I removed my existing stack installation and my .stack directory, installed stack again, created a new stack project and then ran the recommended command in the guide to install ghc-mod and related tools: "stack build -j 8 --copy-compiler-tool ghc-mod hoogle weeder".
I get an error:
Error: While constructing the build plan, the following exceptions were encountered:
In the dependencies for ghc-mod-5.8.0.0: Cabal-2.0.1.1 from stack configuration does not match >=1.18 && <1.25 (latest matching version is 1.24.2.0)
...etc.
Can someone explain what's causing this?