Warning: The install command is a part of the legacy v1 style of cabal usage. Please switch to using either the new project style and the new-install command or the legacy v1-install alias as new-style projects will become the default in the next version of cabal-install. Please file a bug if you cannot replicate a working v1- use case with the new-style commands. For more information, see: https://wiki.haskell.org/Cabal/NewBuild Resolving dependencies... Starting hashable-1.2.7.0 Starting data-default-class-0.1.2.0 Starting primitive-0.6.4.0 Building data-default-class-0.1.2.0 Building primitive-0.6.4.0 Building hashable-1.2.7.0 Completed data-default-class-0.1.2.0 Completed hashable-1.2.7.0 Starting unordered-containers-0.2.9.0 Building unordered-containers-0.2.9.0 Completed unordered-containers-0.2.9.0 Completed primitive-0.6.4.0 Starting vector-0.12.0.2 Building vector-0.12.0.2 Completed vector-0.12.0.2 Starting vector-th-unbox-0.2.1.6 Starting hashtables-1.2.3.1 Building vector-th-unbox-0.2.1.6 Building hashtables-1.2.3.1 Completed vector-th-unbox-0.2.1.6 Starting math-functions-0.3.1.0 Building math-functions-0.3.1.0 Completed hashtables-1.2.3.1 Completed math-functions-0.3.1.0 Starting mwc-random-0.13.6.0 Building mwc-random-0.13.6.0 Completed mwc-random-0.13.6.0 Starting dynamic-graphs-0.1.0.1 Building dynamic-graphs-0.1.0.1 Failed to install dynamic-graphs-0.1.0.1 Build log ( /home/builder/.cabal/logs/ghc-8.6.3/dynamic-graphs-0.1.0.1-HOyQ0sC8xdoLmxf3qgVoPh.log ): cabal: Entering directory '/tmp/cabal-tmp-27933/dynamic-graphs-0.1.0.1' Configuring dynamic-graphs-0.1.0.1... Preprocessing library for dynamic-graphs-0.1.0.1.. Building library for dynamic-graphs-0.1.0.1.. [1 of 7] Compiling Data.Graph.Dynamic.Internal.HashTable ( src/Data/Graph/Dynamic/Internal/HashTable.hs, dist/build/Data/Graph/Dynamic/Internal/HashTable.o ) [2 of 7] Compiling Data.Graph.Dynamic.Internal.Tree ( src/Data/Graph/Dynamic/Internal/Tree.hs, dist/build/Data/Graph/Dynamic/Internal/Tree.o ) [3 of 7] Compiling Data.Graph.Dynamic.Internal.Splay ( src/Data/Graph/Dynamic/Internal/Splay.hs, dist/build/Data/Graph/Dynamic/Internal/Splay.o ) [4 of 7] Compiling Data.Graph.Dynamic.Internal.Random ( src/Data/Graph/Dynamic/Internal/Random.hs, dist/build/Data/Graph/Dynamic/Internal/Random.o ) [5 of 7] Compiling Data.Graph.Dynamic.Internal.Avl ( src/Data/Graph/Dynamic/Internal/Avl.hs, dist/build/Data/Graph/Dynamic/Internal/Avl.o ) [6 of 7] Compiling Data.Graph.Dynamic.EulerTour ( src/Data/Graph/Dynamic/EulerTour.hs, dist/build/Data/Graph/Dynamic/EulerTour.o ) [7 of 7] Compiling Data.Graph.Dynamic.Levels ( src/Data/Graph/Dynamic/Levels.hs, dist/build/Data/Graph/Dynamic/Levels.o ) src/Data/Graph/Dynamic/Levels.hs:238:11: error: • Could not deduce (Control.Monad.Fail.MonadFail m) arising from a do statement with the failable pattern ‘Just sRoot’ from the context: (Eq v, Hashable v, Tree t, PrimMonad m) bound by the type signature for: cut :: forall (t :: * -> * -> * -> *) (m :: * -> *) v. (Eq v, Hashable v, Tree t, PrimMonad m) => Graph t (PrimState m) v -> v -> v -> m Bool at src/Data/Graph/Dynamic/Levels.hs:(211,1)-(213,50) Possible fix: add (Control.Monad.Fail.MonadFail m) to the context of the type signature for: cut :: forall (t :: * -> * -> * -> *) (m :: * -> *) v. (Eq v, Hashable v, Tree t, PrimMonad m) => Graph t (PrimState m) v -> v -> v -> m Bool • In a stmt of a 'do' block: Just sRoot <- ET.findRoot etf smaller In the expression: do aSize <- ET.componentSize etf a bSize <- ET.componentSize etf b let (smaller, _bigger) = ... Just sRoot <- ET.findRoot etf smaller .... In a case alternative: True -> do aSize <- ET.componentSize etf a bSize <- ET.componentSize etf b let (smaller, _bigger) = ... .... | 238 | Just sRoot <- ET.findRoot etf smaller | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cabal: Leaving directory '/tmp/cabal-tmp-27933/dynamic-graphs-0.1.0.1' cabal: Error: some packages failed to install: dynamic-graphs-0.1.0.1-HOyQ0sC8xdoLmxf3qgVoPh failed during the building phase. The exception was: ExitFailure 1