Bug#1021575: haskell-pipes-aeson FTBFS: Couldn't match type

[Adrian Bunk]

Source: haskell-pipes-aeson
Version: 0.4.1.8-4
Severity: serious
Tags: ftbfs bookworm sid

https://buildd.debian.org/status/fetch.php?pkg=haskell-pipes-aeson&arch=amd64&ver=0.4.1.8-4%2Bb4&stamp=1658618925&raw=0

...
src/Pipes/Aeson/Unchecked.hs:34:10: error:
    • Couldn't match type ‘c0’ with ‘Producer' PB.ByteString m0 ()’
      Expected: Data.ByteString.Lazy.Internal.ByteString -> c0
        Actual: Data.ByteString.Lazy.Internal.ByteString
                -> Producer' PB.ByteString m0 ()
      Cannot instantiate unification variable ‘c0’
      with a type involving polytypes: Producer' PB.ByteString m0 ()
    • In the first argument of ‘(.)’, namely ‘PB.fromLazy’
      In the expression: PB.fromLazy . Ae.encode
      In an equation for ‘encode’: encode = PB.fromLazy . Ae.encode
   |
34 | encode = PB.fromLazy . Ae.encode
   |          ^^^^^^^^^^^

src/Pipes/Aeson/Unchecked.hs:34:10: error:
    • Couldn't match type ‘c0’ with ‘Producer' PB.ByteString m ()’
      Expected: a -> Producer' PB.ByteString m ()
        Actual: a -> c0
      Cannot instantiate unification variable ‘c0’
      with a type involving polytypes: Producer' PB.ByteString m ()
    • In the expression: PB.fromLazy . Ae.encode
      In an equation for ‘encode’: encode = PB.fromLazy . Ae.encode
    • Relevant bindings include
        encode :: a -> Producer' PB.ByteString m ()
          (bound at src/Pipes/Aeson/Unchecked.hs:34:1)
   |
34 | encode = PB.fromLazy . Ae.encode
   |          ^^^^^^^^^^^^^^^^^^^^^^^

src/Pipes/Aeson/Unchecked.hs:37:19: error:
    • Couldn't match type: forall x'1 x1.
                           Proxy x'1 x1 () PB.ByteString m1 ()
                     with: Proxy () a () PB.ByteString m ()
      Expected: a -> Proxy () a () PB.ByteString m ()
        Actual: a -> Producer' PB.ByteString m1 ()
    • In the second argument of ‘for’, namely ‘encode’
      In the second argument of ‘(>->)’, namely ‘for cat encode’
      In the expression: p >-> for cat encode
    • Relevant bindings include
        p :: Proxy x' x () a m a'
          (bound at src/Pipes/Aeson/Unchecked.hs:36:41)
   |
37 |     p >-> for cat encode = for p (\a -> PB.fromLazy (Ae.encode a))
   |                   ^^^^^^
...