diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,9 @@
 # Changelog for polysemy-plugin
 
+## 0.2.1.1 (2019-06-26)
+
+- Updated the test suite to test against `polysemy-0.5.0.0`
+
 ## 0.2.1.0 (2019-06-14)
 
 - Greatly improved the plugin's ability to unify polymorphic types when running
diff --git a/polysemy-plugin.cabal b/polysemy-plugin.cabal
--- a/polysemy-plugin.cabal
+++ b/polysemy-plugin.cabal
@@ -1,13 +1,13 @@
 cabal-version: 1.12
 
--- This file has been generated from package.yaml by hpack version 0.31.1.
+-- This file has been generated from package.yaml by hpack version 0.31.2.
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: e4dc8b1a6c6d69287ad57b504d173944aea70ea24df70dab669ea1f70715c3b0
+-- hash: df45f7f2f338b1cac819daf739829c387626de2fb09a1e1c2424004faf90d6b8
 
 name:           polysemy-plugin
-version:        0.2.1.0
+version:        0.2.1.1
 synopsis:       Disambiguate obvious uses of effects.
 description:    Please see the README on GitHub at <https://github.com/isovector/polysemy/tree/master/polysemy-plugin#readme>
 category:       Polysemy
@@ -39,13 +39,13 @@
       src
   default-extensions: DataKinds DeriveFunctor FlexibleContexts GADTs LambdaCase PolyKinds RankNTypes ScopedTypeVariables StandaloneDeriving TypeApplications TypeOperators TypeFamilies UnicodeSyntax
   build-depends:
-      base >=4.7 && <5
-    , containers >=0.6 && <=0.7
-    , ghc >=8.6.3 && <8.7
+      base >=4.9 && <5
+    , containers >=0.5 && <0.7
+    , ghc >=8.4.4 && <9
     , ghc-tcplugins-extra >=0.3 && <0.4
     , polysemy >=0.1
     , syb >=0.7 && <0.8
-    , transformers >=0.5.5.0 && <0.6
+    , transformers >=0.5.2.0 && <0.6
   default-language: Haskell2010
 
 test-suite polysemy-plugin-test
@@ -62,17 +62,19 @@
   hs-source-dirs:
       test
   default-extensions: DataKinds DeriveFunctor FlexibleContexts GADTs LambdaCase PolyKinds RankNTypes ScopedTypeVariables StandaloneDeriving TypeApplications TypeOperators TypeFamilies UnicodeSyntax
-  ghc-options: -threaded -rtsopts -with-rtsopts=-N -fplugin=Polysemy.Plugin -O2
+  ghc-options: -threaded -rtsopts -with-rtsopts=-N -fplugin=Polysemy.Plugin
+  build-tool-depends:
+      hspec-discover:hspec-discover
   build-depends:
-      base >=4.7 && <5
-    , containers >=0.6 && <=0.7
-    , ghc >=8.6.3 && <8.7
+      base >=4.9 && <5
+    , containers >=0.5 && <0.7
+    , ghc >=8.4.4 && <9
     , ghc-tcplugins-extra >=0.3 && <0.4
     , hspec >=2.6.0 && <3
     , inspection-testing >=0.4.2 && <0.5
-    , polysemy >=0.3
+    , polysemy >=0.5.0.0
     , polysemy-plugin
     , should-not-typecheck >=2.1.0 && <3
     , syb >=0.7 && <0.8
-    , transformers >=0.5.5.0 && <0.6
+    , transformers >=0.5.2.0 && <0.6
   default-language: Haskell2010
diff --git a/src/Polysemy/Plugin/InlineRecursiveCalls.hs b/src/Polysemy/Plugin/InlineRecursiveCalls.hs
--- a/src/Polysemy/Plugin/InlineRecursiveCalls.hs
+++ b/src/Polysemy/Plugin/InlineRecursiveCalls.hs
@@ -41,7 +41,7 @@
 containsName n e =
   getAny $
     everything
-      (<>)
+      mappend
       (mkQ (Any False) $ matches n)
       e
 
diff --git a/src/Polysemy/Plugin/Phases.hs b/src/Polysemy/Plugin/Phases.hs
--- a/src/Polysemy/Plugin/Phases.hs
+++ b/src/Polysemy/Plugin/Phases.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE CPP #-}
+
 module Polysemy.Plugin.Phases
   ( extraPhases
   ) where
@@ -28,7 +30,9 @@
     base_mode = SimplMode
       { sm_phase      = error "base_mode"
       , sm_names      = []
+#if __GLASGOW_HASKELL__ >= 804
       , sm_dflags     = dflags
+#endif
       , sm_rules      = option Opt_EnableRewriteRules
       , sm_eta_expand = rules_on
       , sm_inline     = True
diff --git a/test/ExampleSpec.hs b/test/ExampleSpec.hs
--- a/test/ExampleSpec.hs
+++ b/test/ExampleSpec.hs
@@ -1,5 +1,4 @@
 {-# LANGUAGE TemplateHaskell #-}
-{-# LANGUAGE BlockArguments #-}
 {-# OPTIONS_GHC -fplugin=Polysemy.Plugin #-}
 
 module ExampleSpec where
diff --git a/test/InlineRecursiveCallsSpec.hs b/test/InlineRecursiveCallsSpec.hs
--- a/test/InlineRecursiveCallsSpec.hs
+++ b/test/InlineRecursiveCallsSpec.hs
@@ -1,7 +1,12 @@
+{-# LANGUAGE CPP             #-}
 {-# LANGUAGE TemplateHaskell #-}
-{-# OPTIONS_GHC -ddump-simpl -dsuppress-coercions -dsuppress-uniques -dsuppress-idinfo #-}
 
+{-# OPTIONS_GHC -O2 #-}
 
+#if __GLASGOW_HASKELL__ < 804
+{-# OPTIONS_GHC -fplugin=Test.Inspection.Plugin #-}
+#endif
+
 module InlineRecursiveCallsSpec
   ( spec
   ) where
@@ -9,7 +14,6 @@
 import qualified Control.Monad.Trans.State as S
 import           Data.Tuple
 import           Polysemy.Internal
-import           Polysemy.Internal.Effect
 import           Polysemy.Internal.Union
 import           Test.Hspec
 import           Test.Inspection
diff --git a/test/PluginSpec.hs b/test/PluginSpec.hs
--- a/test/PluginSpec.hs
+++ b/test/PluginSpec.hs
@@ -1,5 +1,4 @@
 {-# LANGUAGE AllowAmbiguousTypes        #-}
-{-# LANGUAGE BlockArguments             #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
 {-# LANGUAGE OverloadedStrings          #-}
 
@@ -37,9 +36,8 @@
 err :: Member (Error e) r => Sem r Bool
 err =
   catch
-    do
-      throw undefined
-    \_ -> pure True
+    (throw undefined)
+    (\_ -> pure True)
 
 
 errState :: Num s => Members '[Error e, State s] r => Sem r Bool
diff --git a/test/VDQSpec.hs b/test/VDQSpec.hs
--- a/test/VDQSpec.hs
+++ b/test/VDQSpec.hs
@@ -1,5 +1,4 @@
 {-# LANGUAGE TemplateHaskell #-}
-{-# LANGUAGE BlockArguments #-}
 {-# OPTIONS_GHC -fplugin=Polysemy.Plugin #-}
 
 module VDQSpec where