Suggest default definition of Applicative

ghci> data A a = A a deriving (Show, Functor)
ghci> instance Monad A

<interactive>:3:10: error:
    • No instance for (Applicative A)
        arising from the superclasses of an instance declaration
    • In the instance declaration for ‘Monad A’

could suggest defining it in terms of Monad:

<interactive>:3:10: error:
    • No instance for (Applicative A)
        arising from the superclasses of an instance declaration
    • In the instance declaration for ‘Monad A’
    • Default implementation given a `Monad` instance:
        instance Applicative A where
          pure  = return
          (<*>) = Control.Monad.ap

Trac metadata

Trac field	Value
Version	8.1
Type	FeatureRequest
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	GHCi
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture