fix(xan): fix compat with new base+ghc

A couple of changes necessary to get things working with both ghc 8.8.3
and the new base:

- Explicitly import fail from Control.Monad.Fail in the prelude, since
  it's there instead of the base prelude now
- GHC no longer allows type family equality constraints in quantified
  constraints - which is a bummer - but is avoidable in the one case
  where it was happening
- Explicitly import a constructor from Data.List.NonEmpty

Change-Id: Ia06fc724ddc2d6a3f9024c047ed55eea40bcf408
Reviewed-on: https://cl.tvl.fyi/c/depot/+/744
Tested-by: BuildkiteCI
Reviewed-by: BuildkiteCI
Reviewed-by: Profpatsch <mail@profpatsch.de>

users/glittershark/xanthous/src/Xanthous/AI/Gormlak.hs

@@ -27,7 +27,7 @@ import qualified Xanthous.Entities.RawTypes as Raw
 import           Xanthous.Entities.RawTypes (CreatureType)
 import           Xanthous.Game.State
 import           Xanthous.Game.Lenses
-                 ( Collision(..), entitiesCollision, collisionAt
+                 ( entitiesCollision, collisionAt
                  , character, characterPosition
                  )
 import           Xanthous.Data.EntityMap.Graphics (linesOfSight, canSee)

users/glittershark/xanthous/src/Xanthous/App.hs

@@ -18,6 +18,7 @@ import qualified Data.Aeson as A
 import qualified Data.Vector as V
 import           System.Exit
 import           System.Directory (doesFileExist)
+import           Data.List.NonEmpty (NonEmpty(..))
 --------------------------------------------------------------------------------
 import           Xanthous.App.Common
 import           Xanthous.App.Time

users/glittershark/xanthous/src/Xanthous/Data.hs

@@ -100,7 +100,7 @@ import           Xanthous.Prelude hiding (Left, Down, Right, (.=), elements)
 import           Linear.V2 hiding (_x, _y)
 import qualified Linear.V2 as L
 import           Linear.V4 hiding (_x, _y)
-import           Test.QuickCheck (Arbitrary, CoArbitrary, Function, elements)
+import           Test.QuickCheck (CoArbitrary, Function, elements)
 import           Test.QuickCheck.Arbitrary.Generic
 import           Data.Group
 import           Brick (Location(Location), Edges(..))

users/glittershark/xanthous/src/Xanthous/Entities/Marker.hs

@@ -11,7 +11,6 @@ import           Brick.Widgets.Core (raw)
 --------------------------------------------------------------------------------
 import           Xanthous.Game.State
 import           Xanthous.Data.Entities (EntityAttributes(..))
-import           Xanthous.Data.EntityChar (style)
 --------------------------------------------------------------------------------
 
 -- | Mark on the map - for use in debugging / development only.

users/glittershark/xanthous/src/Xanthous/Game/Lenses.hs

@@ -111,7 +111,7 @@ characterVisibleEntities game =
 entitiesCollision
   :: ( Functor f
     , forall xx. MonoFoldable (f xx)
-    , forall xx. Element (f xx) ~ xx
+    , Element (f SomeEntity) ~ SomeEntity
     , Element (f (Maybe Collision)) ~ Maybe Collision
     , Show (f (Maybe Collision))
     , Show (f SomeEntity)

users/glittershark/xanthous/src/Xanthous/Prelude.hs

@@ -8,6 +8,7 @@ module Xanthous.Prelude
   , module Data.Void
   , module Control.Comonad
   , module Data.Witherable
+  , fail
 
   , (&!)
 
@@ -27,6 +28,7 @@ import Control.Lens hiding (levels, Level)
 import Data.Void
 import Control.Comonad
 import Data.Witherable
+import Control.Monad.Fail (fail)
 --------------------------------------------------------------------------------
 
 ninsertSet