$ cabal install hask
Warning: cannot determine version of /usr/local/bin/jhc :
""
Resolving dependencies...
Configuring hask-0...
Building hask-0...
Preprocessing library hask-0...
[1 of 9] Compiling Hask.Category    ( src/Hask/Category.hs, dist/build/Hask/Category.o )
[2 of 9] Compiling Hask.Iso         ( src/Hask/Iso.hs, dist/build/Hask/Iso.o )
[3 of 9] Compiling Hask.Functor.Faithful ( src/Hask/Functor/Faithful.hs, dist/build/Hask/Functor/Faithful.o )
[4 of 9] Compiling Hask.Category.Polynomial ( src/Hask/Category/Polynomial.hs, dist/build/Hask/Category/Polynomial.o )

src/Hask/Category/Polynomial.hs:63:34: Warning:
    Unticked promoted constructor: ‘Left’.
    Use ‘'Left’ instead of ‘Left’.

src/Hask/Category/Polynomial.hs:63:43: Warning:
    Unticked promoted constructor: ‘Left’.
    Use ‘'Left’ instead of ‘Left’.

src/Hask/Category/Polynomial.hs:64:34: Warning:
    Unticked promoted constructor: ‘Right’.
    Use ‘'Right’ instead of ‘Right’.

src/Hask/Category/Polynomial.hs:64:44: Warning:
    Unticked promoted constructor: ‘Right’.
    Use ‘'Right’ instead of ‘Right’.

src/Hask/Category/Polynomial.hs:67:53: Warning:
    Unticked promoted constructor: ‘Left’.
    Use ‘'Left’ instead of ‘Left’.

src/Hask/Category/Polynomial.hs:67:94: Warning:
    Unticked promoted constructor: ‘Right’.
    Use ‘'Right’ instead of ‘Right’.

src/Hask/Category/Polynomial.hs:70:85: Warning:
    Unticked promoted constructor: ‘Left’.
    Use ‘'Left’ instead of ‘Left’.

src/Hask/Category/Polynomial.hs:74:85: Warning:
    Unticked promoted constructor: ‘Right’.
    Use ‘'Right’ instead of ‘Right’.
[5 of 9] Compiling Hask.Prof        ( src/Hask/Prof.hs, dist/build/Hask/Prof.o )
[6 of 9] Compiling Hask.Tensor      ( src/Hask/Tensor.hs, dist/build/Hask/Tensor.o )
[7 of 9] Compiling Hask.Tensor.Compose ( src/Hask/Tensor/Compose.hs, dist/build/Hask/Tensor/Compose.o )

src/Hask/Tensor/Compose.hs:33:50:
    Illegal type synonym family application in instance:
      Compose c d e f g a
    In the instance declaration for
      ‘Class (f (g a)) (Compose c d e f g a)’

src/Hask/Tensor/Compose.hs:34:50:
    Illegal type synonym family application in instance:
      Compose c d e f g a
    In the instance declaration for ‘f (g a) :=> Compose c d e f g a’

src/Hask/Tensor/Compose.hs:36:50:
    Illegal type synonym family application in instance: Compose c d e
    In the instance declaration for ‘Functor (Compose c d e)’

src/Hask/Tensor/Compose.hs:43:83:
    Illegal type synonym family application in instance:
      Compose c d e f
    In the instance declaration for ‘Functor (Compose c d e f)’

src/Hask/Tensor/Compose.hs:48:116:
    Illegal type synonym family application in instance:
      Compose c d e f g
    In the instance declaration for ‘Functor (Compose c d e f g)’

src/Hask/Tensor/Compose.hs:53:44:
    Illegal type synonym family application in instance:
      Compose c c' c''
    In the instance declaration for
      ‘Semitensor (Compose c c' c'' :: (i -> i) -> (i -> i) -> (i -> i))’

src/Hask/Tensor/Compose.hs:71:24:
    Illegal type synonym family application in instance: Id c a
    In the instance declaration for ‘Class a (Id c a)’

src/Hask/Tensor/Compose.hs:72:24:
    Illegal type synonym family application in instance: Id c a
    In the instance declaration for ‘a :=> Id c a’

src/Hask/Tensor/Compose.hs:74:26:
    Illegal type synonym family application in instance: Id c
    In the instance declaration for ‘Functor (Id c)’

src/Hask/Tensor/Compose.hs:79:15:
    Illegal type synonym family application in instance: Compose c c c
    In the type instance declaration for ‘I’

src/Hask/Tensor/Compose.hs:81:40:
    Illegal type synonym family application in instance: Compose c c c
    In the instance declaration for ‘Semigroup (Compose c c c) (Id c)’

src/Hask/Tensor/Compose.hs:84:40:
    Illegal type synonym family application in instance: Compose c c c
    In the instance declaration for ‘Monoid' (Compose c c c) (Id c)’

src/Hask/Tensor/Compose.hs:87:40:
    Illegal type synonym family application in instance: Compose c c c
    In the instance declaration for
      ‘Cosemigroup (Compose c c c) (Id c)’

src/Hask/Tensor/Compose.hs:90:40:
    Illegal type synonym family application in instance: Compose c c c
    In the instance declaration for ‘Comonoid' (Compose c c c) (Id c)’

src/Hask/Tensor/Compose.hs:93:40:
    Illegal type synonym family application in instance: Compose c c c
    In the instance declaration for
      ‘Tensor' (Compose c c c :: (i -> i) -> (i -> i) -> (i -> i))’
Failed to install hask-0
cabal: Error: some packages failed to install:
hask-0 failed during the building phase. The exception was:
ExitFailure 1