Issue while Haskell instaling Euterpea's dependency, HCodecs did not skip version check for a later version installed

Question

While I was installing Euterpea today, I found HCodecs-0.5.1 (a dependency for Euterpea) was tend to always to beult-fail

So I go to Hackage.Haskell.org, checked that HCo

Answer 1

The problem is that Euterpea has a dependency on exactly version 0.5.1 of HCodecs, and support for the MonadFail Proposal (fully implemented as of GHC 8.8.1) was only added to HCodecs in version 0.5.2. Until Euterpea updates its dependency list, you have two choices to work around this: either pass the --allow-newer command line flag to cabal, which will cause it to ignore upper version bounds, or downgrade your GHC to 8.6.5, the final version that didn't fully implement the MonadFail Proposal. In this case, I recommend the former.