dmoverton / finite-domain Goto Github PK

$ ghci
GHCi, version 8.10.7: https://www.haskell.org/ghc/  :? for help
Prelude> :load Queens.hs 
[1 of 3] Compiling Domain           ( Domain.hs, interpreted )

Domain.hs:54:10: error:
    • No instance for (Semigroup Domain)
        arising from the superclasses of an instance declaration
    • In the instance declaration for ‘Monoid Domain’
   |
54 | instance Monoid Domain where
   |          ^^^^^^^^^^^^^
Failed, no modules loaded.
Prelude>