Resolving dependencies... Configuring ansi-terminal-0.6.2.3... Configuring base-unicode-symbols-0.2.2.4... Building base-unicode-symbols-0.2.2.4... Building ansi-terminal-0.6.2.3... Installed base-unicode-symbols-0.2.2.4 Configuring mtl-2.2.1... Building mtl-2.2.1... Configuring semigroups-0.18.2... Installed ansi-terminal-0.6.2.3 Building semigroups-0.18.2... Configuring stm-2.4.4.1... Installed semigroups-0.18.2 Building stm-2.4.4.1... Configuring transformers-compat-0.5.1.4... Installed mtl-2.2.1 Building transformers-compat-0.5.1.4... Configuring text-1.2.2.1... Installed stm-2.4.4.1 Configuring unix-compat-0.4.2.0... Installed transformers-compat-0.5.1.4 Building text-1.2.2.1... Building unix-compat-0.4.2.0... Installed unix-compat-0.4.2.0 Configuring ansi-wl-pprint-0.6.7.3... Building ansi-wl-pprint-0.6.7.3... Installed ansi-wl-pprint-0.6.7.3 Configuring stm-chans-3.0.0.4... Building stm-chans-3.0.0.4... Configuring regex-base-0.93.2... Installed stm-chans-3.0.0.4 Building regex-base-0.93.2... Configuring mmorph-1.0.7... Installed regex-base-0.93.2 Building mmorph-1.0.7... Installed text-1.2.2.1 Configuring filemanip-0.3.6.3... Building filemanip-0.3.6.3... Installed mmorph-1.0.7 Configuring optparse-applicative-0.13.0.0... Building optparse-applicative-0.13.0.0... Configuring terminal-progress-bar-0.0.1.4... Installed filemanip-0.3.6.3 Building terminal-progress-bar-0.0.1.4... Installed terminal-progress-bar-0.0.1.4 Configuring parsec-3.1.11... Building parsec-3.1.11... Configuring pipes-4.2.0... Installed optparse-applicative-0.13.0.0 Building pipes-4.2.0... Failed to install pipes-4.2.0 Build log ( /home/builder/.cabal/logs/pipes-4.2.0.log ): cabal: Entering directory '/tmp/cabal-tmp-747/pipes-4.2.0' Configuring pipes-4.2.0... Building pipes-4.2.0... Preprocessing library pipes-4.2.0... [1 of 6] Compiling Pipes.Internal ( src/Pipes/Internal.hs, dist/build/Pipes/Internal.o ) src/Pipes/Internal.hs:151:24: error: • Could not deduce (Monad m) arising from a use of ‘observe’ from the context: Functor m bound by the type signature for: hoist :: Functor m => (forall a1. m a1 -> n a1) -> Proxy a' a b' b m b1 -> Proxy a' a b' b n b1 at src/Pipes/Internal.hs:151:5-9 Possible fix: add (Monad m) to the context of the type signature for: hoist :: Functor m => (forall a1. m a1 -> n a1) -> Proxy a' a b' b m b1 -> Proxy a' a b' b n b1 • In the first argument of ‘go’, namely ‘(observe p0)’ In the expression: go (observe p0) In an equation for ‘hoist’: hoist nat p0 = go (observe p0) where go p = case p of { Request a' fa -> Request a' (\ a -> ...) Respond b fb' -> Respond b (\ b' -> ...) M m -> M (nat (m >>= ...)) Pure r -> Pure r } src/Pipes/Internal.hs:156:39: error: • Could not deduce (Monad m) arising from a use of ‘>>=’ from the context: Functor m bound by the type signature for: hoist :: Functor m => (forall a1. m a1 -> n a1) -> Proxy a' a b' b m b1 -> Proxy a' a b' b n b1 at src/Pipes/Internal.hs:151:5-9 Possible fix: add (Monad m) to the context of the inferred type of go :: Proxy a'1 a1 b'1 b2 m r -> Proxy a'1 a1 b'1 b2 n r or the type signature for: hoist :: Functor m => (forall a1. m a1 -> n a1) -> Proxy a' a b' b m b1 -> Proxy a' a b' b n b1 • In the first argument of ‘nat’, namely ‘(m >>= \ p' -> return (go p'))’ In the first argument of ‘M’, namely ‘(nat (m >>= \ p' -> return (go p')))’ In the expression: M (nat (m >>= \ p' -> return (go p'))) cabal: Leaving directory '/tmp/cabal-tmp-747/pipes-4.2.0' Installed parsec-3.1.11 Configuring natural-sort-0.1.2... Configuring csv-0.1.2... Building natural-sort-0.1.2... Building csv-0.1.2... Configuring regex-tdfa-1.2.2... Installed csv-0.1.2 Installed natural-sort-0.1.2 Building regex-tdfa-1.2.2... Installed regex-tdfa-1.2.2 cabal: Error: some packages failed to install: lentil-1.0.3.1 depends on pipes-4.2.0 which failed to install. pipes-4.2.0 failed during the building phase. The exception was: ExitFailure 1