diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,9 @@
 # Revision history for inspection-testing
 
+## 0.4.6.1 -- 2022-05-20
+
+* Support GHC 9.4 (thanks @parsonsmatt)
+
 ## 0.4.6.0 -- 2020-08-23
 
 * Support GHC 9.2 (thanks @Bodigrim)
diff --git a/inspection-testing.cabal b/inspection-testing.cabal
--- a/inspection-testing.cabal
+++ b/inspection-testing.cabal
@@ -1,5 +1,5 @@
 name:                inspection-testing
-version:             0.4.6.0
+version:             0.4.6.1
 synopsis:            GHC plugin to do inspection testing
 description:         Some carefully crafted libraries make promises to their
                      users beyond functionality and performance.
@@ -34,7 +34,7 @@
 build-type:          Simple
 extra-source-files:  ChangeLog.md, README.md
 cabal-version:       >=1.10
-Tested-With:         GHC == 8.0.2, GHC == 8.2.*, GHC == 8.4.*, GHC ==8.6.*, GHC ==8.8.*, GHC ==8.10.*, GHC ==9.0.*, GHC ==9.2.*
+Tested-With:         GHC == 8.0.2, GHC == 8.2.*, GHC == 8.4.*, GHC ==8.6.*, GHC ==8.8.*, GHC ==8.10.*, GHC ==9.0.*, GHC ==9.2.*, GHC ==9.4.*
 
 source-repository head
   type:     git
@@ -45,8 +45,8 @@
                        Test.Inspection.Plugin
                        Test.Inspection.Core
   hs-source-dirs:      src
-  build-depends:       base >=4.9 && <4.17
-  build-depends:       ghc >= 8.0.2 && <9.3
+  build-depends:       base >=4.9 && <4.18
+  build-depends:       ghc >= 8.0.2 && <9.5
   build-depends:       template-haskell
   build-depends:       containers
   build-depends:       transformers
diff --git a/src/Test/Inspection/Plugin.hs b/src/Test/Inspection/Plugin.hs
--- a/src/Test/Inspection/Plugin.hs
+++ b/src/Test/Inspection/Plugin.hs
@@ -21,6 +21,11 @@
 import qualified Data.Map.Strict as M
 import qualified Language.Haskell.TH.Syntax as TH
 
+#if MIN_VERSION_ghc(9,4,0)
+import GHC.Types.Error
+import GHC.Driver.Session
+#endif
+
 #if MIN_VERSION_ghc(9,0,0)
 import GHC.Plugins hiding (SrcLoc)
 import GHC.Utils.Outputable as Outputable
@@ -317,18 +322,9 @@
 
 proofPass :: UponFailure -> ReportingMode -> ModGuts -> CoreM ModGuts
 proofPass upon_failure report guts = do
-    dflags <- getDynFlags
-    let noopt = optLevel dflags < 1
-    case (noopt, upon_failure) of
-        (True, SkipO0) -> pure guts
-        (_   , _     ) -> do
-            when noopt $ do
-                warnMsg
-#if MIN_VERSION_GLASGOW_HASKELL(8,9,0,0)
-                    NoReason
-#endif
-                    $ fsep $ map text
-                    $ words "Test.Inspection: Compilation without -O detected. Expect optimizations to fail."
+    case upon_failure of
+        SkipO0 -> pure guts
+        _ -> do
             let (guts', obligations) = extractObligations guts
             (toStore, stats) <- (concat `bimap` M.unionsWith (+)) . unzip <$>
                 mapM (checkObligation report guts') obligations
@@ -352,7 +348,6 @@
                     errorMsg $ text "inspection testing unsuccessful" $$ summary_message
                     case upon_failure of
                         KeepGoing           -> return ()
-                        KeepGoingO0 | noopt -> return ()
                         _                   -> liftIO $ exitFailure -- kill the compiler. Is there a nicer way?
 
             return guts''