PartialTypeSignaturesDisabled.hs:4:8: error:
    • Found type wildcard ‘_’ standing for ‘Bool’
      To use the inferred type, enable PartialTypeSignatures
    • In the type signature:
        foo :: _ -> _
    • Relevant bindings include
        foo :: Bool -> Bool (bound at PartialTypeSignaturesDisabled.hs:5:1)

PartialTypeSignaturesDisabled.hs:4:13: error:
    • Found type wildcard ‘_’ standing for ‘Bool’
      To use the inferred type, enable PartialTypeSignatures
    • In the type signature:
        foo :: _ -> _
    • Relevant bindings include
        foo :: Bool -> Bool (bound at PartialTypeSignaturesDisabled.hs:5:1)