Check for dangerous and unsafe functions

[yaxu]

Useful list and hlint config here:
https://github.com/NorfairKing/haskell-dangerous-functions

[jwaldmann]

I am looking into this (as a way of refreshing my knowledge of Tidal's code...) NB: NorfairKing/haskell-dangerous-functions#18

[jwaldmann]

With this "dangerous function" hlint.yaml, I get this report on Tidal's current main branch: https://www.imn.htwk-leipzig.de/~waldmann/etc/Tidal/

This reports all warnings (including those from hlint's default settings) I guess that "dangerous functions" are listed under "avoid restricted function".

NB: It's a bit strange (for me) to see "return" there, but apparently it should be "pure". That's a matter of style only? No, this page https://gitlab.haskell.org/ghc/ghc/-/wikis/proposal/monad-of-no-return says it's "error prone" (default declarations of Applicative.pure and Monad.return refer to each other => non-termination).