GHC 8 build failure: type checker not happy

[deepfire]

Building dependent-sum-0.3.2.1...
Preprocessing library dependent-sum-0.3.2.1...
[1 of 4] Compiling Data.GADT.Show   ( src/Data/GADT/Show.hs, dist/build/Data/GADT/Show.o )
[2 of 4] Compiling Data.GADT.Compare ( src/Data/GADT/Compare.hs, dist/build/Data/GADT/Compare.o )

src/Data/GADT/Compare.hs:60:30: error:
    • Couldn't match type ‘((forall k2 (a1 :: k2). a1 :~: a1) -> t0)
                           -> t0’
                     with ‘forall b. (forall (a1 :: k1). x := a1 -> b) -> b’
      Expected type: [(forall b. (forall (a :: k1). x := a -> b) -> b,
                       String)]
        Actual type: [(((forall k (a :: k). a :~: a) -> t0) -> t0,
                       String)]
    • In the expression: return (\ x -> x Refl, rest)
      In an equation for ‘f’:
          f (Refl, rest) = return (\ x -> x Refl, rest)
      In an equation for ‘greadsPrec’:
          greadsPrec p s
            = readsPrec p s >>= f
            where
                f ::
                  (x := x, String)
                  -> [(forall b. (forall a. x := a -> b) -> b, String)]
                f (Refl, rest) = return (\ x -> x Refl, rest)
    • Relevant bindings include
        f :: (x := x, String)
             -> [(forall b. (forall (a :: k1). x := a -> b) -> b, String)]
          (bound at src/Data/GADT/Compare.hs:60:13)

src/Data/GADT/Compare.hs:94:21: error:
    • Couldn't match type ‘forall k (a2 :: k). a2 :~: a2’
                     with ‘a :~: a’
      Expected type: Maybe (a1 := b)
        Actual type: Maybe (forall k (a :: k). a :~: a)
    • In the expression: Just Refl
      In an equation for ‘geq’: geq Refl Refl = Just Refl
      In the instance declaration for ‘GEq ((:=) a)’
    • Relevant bindings include
        geq :: a := a1 -> a := b -> Maybe (a1 := b)
          (bound at src/Data/GADT/Compare.hs:94:5)
builder for ‘/nix/store/hb5kgbgqzhdmsw5yy80dbqkg0h6i3prd-dependent-sum-0.3.2.1.drv’ failed with exit code 1
error: build of ‘/nix/store/hb5kgbgqzhdmsw5yy80dbqkg0h6i3prd-dependent-sum-0.3.2.1.drv’ failed

[mokus0]

Should be fixed in latest hackage version (0.3.2.2)

[niteria]

FYI, with the upcoming GHC 8.0.2 0217326 is needed and 0.4 is the only version that works.