RULE may not fire

[ivan-m]

When loaded in ghci with -Wdeferred-type-errors, I get these warnings:

[3 of 4] Compiling Control.Quiver   ( /Users/ivan/Haskell/quiver/src/Control/Quiver.hs, interpreted )

/Users/ivan/Haskell/quiver/src/Control/Quiver.hs:262:20: warning: [-Wdeferred-type-errors]
    • Could not deduce (Functor f) arising from a use of ‘>->>’
      from the context: Functor (P a a' c c' f)
        bound by the RULE "qcompose/fmap"
        at /Users/ivan/Haskell/quiver/src/Control/Quiver.hs:(259,11)-(262,47)
      Possible fix:
        add (Functor f) to the context of the RULE "qcompose/fmap"
    • In the second argument of ‘fmap’, namely ‘(p >->> q)’
      In the expression: fmap fn (p >->> q)
      When checking the transformation rule "qcompose/fmap"

/Users/ivan/Haskell/quiver/src/Control/Quiver.hs:262:32: warning: [-Wdeferred-type-errors]
    • Could not deduce (Functor f) arising from a use of ‘qcompose'’
      from the context: Functor (P a a' c c' f)
        bound by the RULE "qcompose/fmap"
        at /Users/ivan/Haskell/quiver/src/Control/Quiver.hs:(259,11)-(262,47)
      Possible fix:
        add (Functor f) to the context of the RULE "qcompose/fmap"
    • In the expression: qcompose' fn p q
      When checking the transformation rule "qcompose/fmap"

I'm not sure if this is something that's overly wrong/paranoid about -Wdeferred-type-errors, but it should probably be checked that this RULE does indeed fire when expected.