megaparsec-6.*

[zaoqi]

src/Oczor/Parser/ParserState.hs:9:1: error:
    Failed to load interface for ‘Text.Megaparsec.String’
    Perhaps you meant
      Text.Megaparsec.Stream (from megaparsec-6.2.0)
      Text.Megaparsec.Error (from megaparsec-6.2.0)
      Text.Megaparsec.Perm (from megaparsec-6.2.0)
    Use -v to see a list of the files searched for.

[nponeccop]

Use stack to build it. Non-stack builds are a joke these days.

Also, the problem shouldn't happen unless you use --allow-newer as there is an explicit constraint to 5.x in .cabal