Re-enable ghc-8.6, Add -Wcompat

butcher.cabal

@@ -37,7 +37,7 @@ library
   other-modules:       UI.Butcher.Monadic.Internal.Types
                        UI.Butcher.Monadic.Internal.Core
   build-depends:
-    { base >=4.9 && <4.12
+    { base >=4.9 && <4.13
     , free < 5.2
     , unsafe < 0.1
     , microlens <0.5
@@ -80,6 +80,7 @@ library
   }
   ghc-options: {
     -Wall
+    -Wcompat
     -fno-spec-constr
     -fno-warn-unused-imports
     -fno-warn-orphans

iridium.yaml

@@ -27,8 +27,8 @@ checks:
         version: "8.2.2"
       - compiler: "ghc"
         version: "8.4.3"
-      # - compiler: "ghc"
-      #   version: "8.6.1"
+      - compiler: "ghc"
+        version: "8.6.1"
     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
@@ -36,6 +36,7 @@ checks:
     enabled: True
   compiler-warnings:
     enabled: True
+    enable-compat: False
   documentation:
     enabled: True
   hlint: