Resolving dependencies... Configuring base-orphans-0.7... Configuring cabal-doctest-1.0.6... Building cabal-doctest-1.0.6... Building base-orphans-0.7... Installed base-orphans-0.7 Configuring managed-1.0.6... Installed cabal-doctest-1.0.6 Configuring semigroups-0.18.4... Building managed-1.0.6... Building semigroups-0.18.4... Installed managed-1.0.6 Configuring th-abstraction-0.2.6.0... Installed semigroups-0.18.4 Configuring transformers-compat-0.6.1.5... Building th-abstraction-0.2.6.0... Building transformers-compat-0.6.1.5... Installed th-abstraction-0.2.6.0 Installed transformers-compat-0.6.1.5 Configuring tagged-0.8.5... Configuring contravariant-1.4.1... Building tagged-0.8.5... Building contravariant-1.4.1... Installed tagged-0.8.5 Configuring distributive-0.5.3... Installed contravariant-1.4.1 Building distributive-0.5.3... Installed distributive-0.5.3 Configuring comonad-5.0.3... Building comonad-5.0.3... Installed comonad-5.0.3 Configuring bifunctors-5.5.2... Building bifunctors-5.5.2... Installed bifunctors-5.5.2 Configuring profunctors-5.2.2... Building profunctors-5.2.2... Installed profunctors-5.2.2 Configuring potoki-core-0.9... Building potoki-core-0.9... Failed to install potoki-core-0.9 Build log ( /home/builder/.cabal/logs/ghc-8.2.2/potoki-core-0.9-8ai5ETViLC4gHoi7sucQ4.log ): cabal: Entering directory '/tmp/cabal-tmp-14091/potoki-core-0.9' Configuring potoki-core-0.9... Preprocessing library for potoki-core-0.9.. Building library for potoki-core-0.9.. [1 of 7] Compiling Potoki.Core.Prelude ( library/Potoki/Core/Prelude.hs, dist/build/Potoki/Core/Prelude.o ) [2 of 7] Compiling Potoki.Core.Types ( library/Potoki/Core/Types.hs, dist/build/Potoki/Core/Types.o ) [3 of 7] Compiling Potoki.Core.Fetch ( library/Potoki/Core/Fetch.hs, dist/build/Potoki/Core/Fetch.o ) [4 of 7] Compiling Potoki.Core.Produce ( library/Potoki/Core/Produce.hs, dist/build/Potoki/Core/Produce.o ) library/Potoki/Core/Produce.hs:12:13: error: • Couldn't match type ‘IO’ with ‘Managed’ Expected type: Managed (IORef (Maybe a)) Actual type: IO (IORef (Maybe a)) • In a stmt of a 'do' block: refX <- newIORef (Just x) In the second argument of ‘($)’, namely ‘do refX <- newIORef (Just x) return (A.maybeRef refX, pure ())’ In the expression: Produce $ do refX <- newIORef (Just x) return (A.maybeRef refX, pure ()) | 12 | refX <- newIORef (Just x) | ^^^^^^^^^^^^^^^^^ library/Potoki/Core/Produce.hs:13:5: error: • Couldn't match type ‘(Fetch a, f0 ())’ with ‘Fetch a’ Expected type: Managed (Fetch a) Actual type: Managed (Fetch a, f0 ()) • In a stmt of a 'do' block: return (A.maybeRef refX, pure ()) In the second argument of ‘($)’, namely ‘do refX <- newIORef (Just x) return (A.maybeRef refX, pure ())’ In the expression: Produce $ do refX <- newIORef (Just x) return (A.maybeRef refX, pure ()) • Relevant bindings include refX :: IORef (Maybe a) (bound at library/Potoki/Core/Produce.hs:12:5) x :: a (bound at library/Potoki/Core/Produce.hs:11:8) pure :: a -> Produce a (bound at library/Potoki/Core/Produce.hs:11:3) | 13 | return (A.maybeRef refX, pure ()) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cabal: Leaving directory '/tmp/cabal-tmp-14091/potoki-core-0.9' cabal: Error: some packages failed to install: potoki-core-0.9-8ai5ETViLC4gHoi7sucQ4 failed during the building phase. The exception was: ExitFailure 1