T16179.hs:7:30: warning: [GHC-20042] [-Wderiving-defaults (in -Wdefault)]
    • Both DeriveAnyClass and GeneralizedNewtypeDeriving are enabled
      Defaulting to the DeriveAnyClass strategy for instantiating C
    • In the newtype declaration for ‘T’
    Suggested fix:
      Use DerivingStrategies
      to pick a different strategy