Adapt for ghc-8.2.1

butcher.cabal

@@ -41,7 +41,7 @@ library
   other-modules:       UI.Butcher.Monadic.Internal.Types
                        UI.Butcher.Monadic.Internal.Core
   build-depends:
-    { base >=4.8 && <4.10
+    { base >=4.8 && <4.11
     , free
     , unsafe
     , microlens
@@ -104,7 +104,7 @@ test-suite tests
   type:             exitcode-stdio-1.0
   default-language: Haskell2010
   build-depends:
-    { base >=4.8 && <4.10
+    { base >=4.8 && <4.11
     , butcher
     , free
     , unsafe

iridium.yaml

@@ -25,6 +25,8 @@ checks:
         version: "7.10.3"
       - compiler: "ghc"
         version: "8.0.2"
+      - compiler: "ghc"
+        version: "8.2.1"
     compilers-help: |
       for this to work, cabal will need the paths to the actual
       compilers to be configured; see the note about the user-global

srcinc/prelude.inc

@@ -351,6 +351,7 @@ import System.IO                          ( hFlush
                                           )
 
 import Data.Typeable                      ( Typeable
+                                          , cast
                                           )
 
 import Control.Arrow                      ( first