ghci errors

fmap

λ [9]: fmap f [1]                                                                                                             
Out [9]: 

<interactive>:186:1: error:
    • Ambiguous type variable ‘f0’ arising from a use of ‘print’
      prevents the constraint ‘(Show (f0 Integer))’ from being solved.
      Probable fix: use a type annotation to specify what ‘f0’ should be.
      These potential instances exist:
        instance Show a => Show (ZipList a)
          -- Defined in ‘Control.Applicative’
        instance Show a => Show (Complex a) -- Defined in ‘Data.Complex’
        instance (Show a, Show b) => Show (Either a b)
          -- Defined in ‘Data.Either’
        ...plus 53 others
        ...plus 48 instances involving out-of-scope types
        (use -fprint-potential-instances to see them all)
    • In a stmt of an interactive GHCi command: print it