Baffling errors where GHC appears to be ignoring the types I've added to functions.

gistfile1.hs

renderRoute :: HasRep as => S.Path as -> HVectElim as H.AttributeValue
renderRoute path = 
  let curryIt :: (HVect as -> H.AttributeValue) -> HVectElim as H.AttributeValue
      curryIt = hVectCurry
      uncurryIt :: HVectElim as Text -> HVect as -> Text
      uncurryIt = hVectUncurry
      renderIt :: S.Path as -> HVectElim as Text
      renderIt = S.renderRoute
  in  curryIt $ fmap H.textValue $ uncurryIt $ renderIt path

{-
src/MyProject/WebSupport.hs:26:17:
    Could not deduce (HasRep as1) arising from a use of `hVectCurry'
    from the context (HasRep as)
      bound by the type signature for
                 renderRoute :: HasRep as =>
                                S.Path as -> HVectElim as H.AttributeValue
      at src/MyProject/WebSupport.hs:23:16-70
    Possible fix:
      add (HasRep as1) to the context of
        the type signature for
          curryIt :: (HVect as1 -> H.AttributeValue)
                     -> HVectElim as1 H.AttributeValue
        or the type signature for
             renderRoute :: HasRep as =>
                            S.Path as -> HVectElim as H.AttributeValue
    In the expression: hVectCurry
    In an equation for `curryIt': curryIt = hVectCurry
    In the expression:
      let
        curryIt ::
          (HVect as -> H.AttributeValue) -> HVectElim as H.AttributeValue
        curryIt = hVectCurry
        uncurryIt :: HVectElim as Text -> HVect as -> Text
        ....
      in curryIt $ fmap H.textValue $ uncurryIt $ renderIt path

src/MyProject/WebSupport.hs:30:18:
    Could not deduce (HasRep as1) arising from a use of `S.renderRoute'
    from the context (HasRep as)
      bound by the type signature for
                 renderRoute :: HasRep as =>
                                S.Path as -> HVectElim as H.AttributeValue
      at src/MyProject/WebSupport.hs:23:16-70
    Possible fix:
      add (HasRep as1) to the context of
        the type signature for renderIt :: S.Path as1 -> HVectElim as1 Text
        or the type signature for
             renderRoute :: HasRep as =>
                            S.Path as -> HVectElim as H.AttributeValue
    In the expression: S.renderRoute
    In an equation for `renderIt': renderIt = S.renderRoute
    In the expression:
      let
        curryIt ::
          (HVect as -> H.AttributeValue) -> HVectElim as H.AttributeValue
        curryIt = hVectCurry
        uncurryIt :: HVectElim as Text -> HVect as -> Text
        ....
      in curryIt $ fmap H.textValue $ uncurryIt $ renderIt path

src/MyProject/WebSupport.hs:31:7:
    Could not deduce (HVectElim as H.AttributeValue
                      ~ HVectElim as0 H.AttributeValue)
    from the context (HasRep as)
      bound by the type signature for
                 renderRoute :: HasRep as =>
                                S.Path as -> HVectElim as H.AttributeValue
      at src/MyProject/WebSupport.hs:23:16-70
    NB: `HVectElim' is a type function, and may not be injective
    The type variable `as0' is ambiguous
    Possible fix: add a type signature that fixes these type variable(s)
    In the expression:
      curryIt $ fmap H.textValue $ uncurryIt $ renderIt path
    In the expression:
      let
        curryIt ::
          (HVect as -> H.AttributeValue) -> HVectElim as H.AttributeValue
        curryIt = hVectCurry
        uncurryIt :: HVectElim as Text -> HVect as -> Text
        ....
      in curryIt $ fmap H.textValue $ uncurryIt $ renderIt path
    In an equation for `renderRoute':
        renderRoute path
          = let
              curryIt ::
                (HVect as -> H.AttributeValue) -> HVectElim as H.AttributeValue
              curryIt = hVectCurry
              ....
            in curryIt $ fmap H.textValue $ uncurryIt $ renderIt path

src/MyProject/WebSupport.hs:31:48:
    Could not deduce (HVectElim as0 Text ~ HVectElim as Text)
    from the context (HasRep as)
      bound by the type signature for
                 renderRoute :: HasRep as =>
                                S.Path as -> HVectElim as H.AttributeValue
      at src/MyProject/WebSupport.hs:23:16-70
    NB: `HVectElim' is a type function, and may not be injective
    The type variable `as0' is ambiguous
    Possible fix: add a type signature that fixes these type variable(s)
    In the return type of a call of `renderIt'
    In the second argument of `($)', namely `renderIt path'
    In the second argument of `($)', namely `uncurryIt $ renderIt path'


-}