From ffbbffbb094650dc6f74c7f40f0d17b6ae2d10e3 Mon Sep 17 00:00:00 2001
From: jappeace-sloth <sloth@jappie.me>
Date: Sun, 19 Apr 2026 18:56:34 +0000
Subject: [PATCH 1/5] Replace all fromIntegral with unwitch type-safe
 conversions
MIME-Version: 1.0
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Content-Transfer-Encoding: 8bit

Eliminate every fromIntegral call (70+) across 20 files by using
explicit unwitch conversion functions. This makes numeric type
conversions self-documenting and catches unsafe casts at compile time.

Conversion patterns used:
- Int32 ↔ CInt: Int32.toCInt / CInt.toInt32 (total)
- CInt → Int: CInt.toInt (total, for IntMap keys and BS lengths)
- Int → CInt: Int.toCInt with maybe 0 id (partial)
- Int → Word8: Int.toWord8 with maybe 0 id (partial, hex parsing)
- Word8 → Int/Double: Word8.toInt / Word8.toDouble (total)
- Int32 → Int (IntMap keys): CInt.toInt . Int32.toCInt (total chain,
  avoids Int32.toInt which returns Maybe due to Haskell spec)
- Int32/CInt → Double: Int32.toDouble / CInt.toDouble (total)

Added unwitch 2.2.0 to cabal deps (library, test-suite, redraw-demo)
and to both nix overlays (hpkgs.nix for native, cross-deps.nix for
Android cross-compilation).

Prompt: replace all primitive conversions in hatter with unwitch

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 hatter.cabal                 |  9 ++++++---
 nix/cross-deps.nix           |  8 ++++++++
 nix/hpkgs.nix                |  4 ++++
 src/Hatter.hs                | 13 +++++++------
 src/Hatter/Action.hs         | 16 ++++++++++++----
 src/Hatter/Animation.hs      | 10 +++++++++-
 src/Hatter/AuthSession.hs    | 13 ++++++++++---
 src/Hatter/Ble.hs            |  3 ++-
 src/Hatter/BottomSheet.hs    | 15 +++++++++++----
 src/Hatter/Camera.hs         | 31 +++++++++++++++++++------------
 src/Hatter/Dialog.hs         | 13 ++++++++++---
 src/Hatter/Http.hs           | 18 +++++++++++++-----
 src/Hatter/Permission.hs     | 15 +++++++++++----
 src/Hatter/PlatformSignIn.hs | 13 ++++++++++---
 src/Hatter/Render.hs         |  5 +++--
 src/Hatter/SecureStorage.hs  | 21 ++++++++++++++-------
 src/Hatter/UIBridge.hs       | 21 ++++++++++++---------
 src/Hatter/Widget.hs         | 10 ++++++----
 test/RedrawDemoMain.hs       |  5 +++--
 test/Test/AppContextTests.hs |  5 +++--
 20 files changed, 173 insertions(+), 75 deletions(-)

diff --git a/hatter.cabal b/hatter.cabal
index 4b812c8c..d5a3e87a 100644
--- a/hatter.cabal
+++ b/hatter.cabal
@@ -119,7 +119,8 @@ library
       containers < 1,
       bytestring < 1,
       transformers < 0.7,
-      time
+      time,
+      unwitch >= 2.2.0 && < 3
   c-sources:
       cbits/android_stubs.c
       cbits/platform_log.c
@@ -191,7 +192,8 @@ executable redraw-demo
       test
   build-depends:
       hatter,
-      text
+      text,
+      unwitch >= 2.2.0 && < 3
 
 executable confetti-repro-demo
   import: common-options
@@ -250,4 +252,5 @@ test-suite unit
       text,
       bytestring,
       directory,
-      filepath
+      filepath,
+      unwitch >= 2.2.0 && < 3
diff --git a/nix/cross-deps.nix b/nix/cross-deps.nix
index 2621d4b6..13aa5e96 100644
--- a/nix/cross-deps.nix
+++ b/nix/cross-deps.nix
@@ -228,10 +228,18 @@ WRAPPER
         });
     } else {};
 
+  unwitchOverride = self: super: {
+    unwitch = self.callCabal2nix "unwitch" (builtins.fetchTarball {
+      url = "https://hackage.haskell.org/package/unwitch-2.2.0/unwitch-2.2.0.tar.gz";
+      sha256 = "sha256:he/wdUN1XOcEo0VTmJVRrdQnGmZldxgCPCxlSDvzd9c=";
+    }) {};
+  };
+
   defaultOverrides =
     let
       common = pkgs.lib.composeManyExtensions [
         vectorOverride
+        unwitchOverride
         thPackageDbOverride
         thIservOverride
         hatterOverride
diff --git a/nix/hpkgs.nix b/nix/hpkgs.nix
index 7c056584..a9d5bf6c 100644
--- a/nix/hpkgs.nix
+++ b/nix/hpkgs.nix
@@ -9,5 +9,9 @@ pkgs.haskellPackages.override {
     # NB this is a bit silly because nix files are now considered for the build
     # bigger projects should consider putting haskell stuff in a subfolder
     hatter-project = hnew.callCabal2nix "hatter" ../. { };
+    unwitch = hnew.callCabal2nix "unwitch" (builtins.fetchTarball {
+      url = "https://hackage.haskell.org/package/unwitch-2.2.0/unwitch-2.2.0.tar.gz";
+      sha256 = "sha256:he/wdUN1XOcEo0VTmJVRrdQnGmZldxgCPCxlSDvzd9c=";
+    }) {};
   };
 }
diff --git a/src/Hatter.hs b/src/Hatter.hs
index 328c2abf..883f4dcd 100644
--- a/src/Hatter.hs
+++ b/src/Hatter.hs
@@ -130,6 +130,7 @@ import Foreign.C.Types (CDouble(..), CInt(..))
 import Foreign.Ptr (Ptr, castPtr, nullPtr)
 import Data.ByteString qualified as BS
 import Data.Word (Word8)
+import Unwitch.Convert.CInt qualified as CInt
 import Hatter.Action
   ( Action(..)
   , OnChange(..)
@@ -316,7 +317,7 @@ haskellOnUIEvent :: Ptr AppContext -> CInt -> IO ()
 haskellOnUIEvent ctxPtr callbackId =
   withExceptionHandler ctxPtr $ do
     appCtx <- derefAppContext ctxPtr
-    dispatchEvent (acRenderState appCtx) (fromIntegral callbackId)
+    dispatchEvent (acRenderState appCtx) (CInt.toInt32 callbackId)
     renderView ctxPtr
 
 foreign export ccall haskellOnUIEvent :: Ptr AppContext -> CInt -> IO ()
@@ -332,7 +333,7 @@ haskellOnUITextChange ctxPtr callbackId cstr =
   withExceptionHandler ctxPtr $ do
     appCtx <- derefAppContext ctxPtr
     str <- peekCString cstr
-    dispatchTextEvent (acRenderState appCtx) (fromIntegral callbackId) (pack str)
+    dispatchTextEvent (acRenderState appCtx) (CInt.toInt32 callbackId) (pack str)
     renderView ctxPtr
 
 foreign export ccall haskellOnUITextChange :: Ptr AppContext -> CInt -> CString -> IO ()
@@ -452,7 +453,7 @@ haskellOnCameraResult ctxPtr requestId statusCode
     appCtx <- derefAppContext ctxPtr
     maybeImageData <- if imageDataPtr == nullPtr || imageDataLen <= 0
       then pure Nothing
-      else Just <$> BS.packCStringLen (castPtr imageDataPtr, fromIntegral imageDataLen)
+      else Just <$> BS.packCStringLen (castPtr imageDataPtr, CInt.toInt imageDataLen)
     dispatchCameraResult (acCameraState appCtx) requestId statusCode
       maybeImageData width height
 
@@ -467,7 +468,7 @@ haskellOnVideoFrame :: Ptr AppContext -> CInt
 haskellOnVideoFrame ctxPtr requestId frameDataPtr frameDataLen width height =
   withExceptionHandler ctxPtr $ do
     appCtx <- derefAppContext ctxPtr
-    frameBytes <- BS.packCStringLen (castPtr frameDataPtr, fromIntegral frameDataLen)
+    frameBytes <- BS.packCStringLen (castPtr frameDataPtr, CInt.toInt frameDataLen)
     dispatchVideoFrame (acCameraState appCtx) requestId frameBytes width height
 
 foreign export ccall haskellOnVideoFrame
@@ -480,7 +481,7 @@ haskellOnAudioChunk :: Ptr AppContext -> CInt
 haskellOnAudioChunk ctxPtr requestId audioDataPtr audioDataLen =
   withExceptionHandler ctxPtr $ do
     appCtx <- derefAppContext ctxPtr
-    audioBytes <- BS.packCStringLen (castPtr audioDataPtr, fromIntegral audioDataLen)
+    audioBytes <- BS.packCStringLen (castPtr audioDataPtr, CInt.toInt audioDataLen)
     dispatchAudioChunk (acCameraState appCtx) requestId audioBytes
 
 foreign export ccall haskellOnAudioChunk
@@ -508,7 +509,7 @@ haskellOnHttpResult ctxPtr requestId resultCode httpStatus
     maybeHeaders <- peekOptionalCString cHeaders
     responseBody <- if bodyPtr == nullPtr || bodyLen <= 0
       then pure BS.empty
-      else BS.packCStringLen (castPtr bodyPtr, fromIntegral bodyLen)
+      else BS.packCStringLen (castPtr bodyPtr, CInt.toInt bodyLen)
     dispatchHttpResult (acHttpState appCtx) requestId resultCode httpStatus
       maybeHeaders responseBody
 
diff --git a/src/Hatter/Action.hs b/src/Hatter/Action.hs
index 5080e4a4..7278f6af 100644
--- a/src/Hatter/Action.hs
+++ b/src/Hatter/Action.hs
@@ -40,6 +40,8 @@ import Data.Int (Int32)
 import Data.IntMap.Strict (IntMap)
 import Data.IntMap.Strict qualified as IntMap
 import Data.Text (Text)
+import Unwitch.Convert.CInt qualified as CInt
+import Unwitch.Convert.Int32 qualified as Int32
 
 -- | An opaque handle to a click / tap callback.
 -- Carries only an 'Int32' identifier, so it derives 'Eq' and 'Show'.
@@ -86,7 +88,7 @@ newtype ActionM a = ActionM (ActionState -> IO a)
 createAction :: IO () -> ActionM Action
 createAction callback = ActionM $ \state -> do
   handleId <- readIORef (asNextId state)
-  modifyIORef' (asCallbacks state) (IntMap.insert (fromIntegral handleId) callback)
+  modifyIORef' (asCallbacks state) (IntMap.insert (int32ToIntKey handleId) callback)
   modifyIORef' (asNextId state) (+ 1)
   pure (Action handleId)
 
@@ -94,7 +96,7 @@ createAction callback = ActionM $ \state -> do
 createOnChange :: (Text -> IO ()) -> ActionM OnChange
 createOnChange callback = ActionM $ \state -> do
   handleId <- readIORef (asNextId state)
-  modifyIORef' (asTextCallbacks state) (IntMap.insert (fromIntegral handleId) callback)
+  modifyIORef' (asTextCallbacks state) (IntMap.insert (int32ToIntKey handleId) callback)
   modifyIORef' (asNextId state) (+ 1)
   pure (OnChange handleId)
 
@@ -107,11 +109,17 @@ runActionM state (ActionM f) = f state
 lookupAction :: ActionState -> Int32 -> IO (Maybe (IO ()))
 lookupAction state handleId = do
   callbacks <- readIORef (asCallbacks state)
-  pure (IntMap.lookup (fromIntegral handleId) callbacks)
+  pure (IntMap.lookup (int32ToIntKey handleId) callbacks)
 
 -- | Look up a text-change callback by handle ID.
 -- Returns 'Nothing' if the ID is not registered.
 lookupTextAction :: ActionState -> Int32 -> IO (Maybe (Text -> IO ()))
 lookupTextAction state handleId = do
   callbacks <- readIORef (asTextCallbacks state)
-  pure (IntMap.lookup (fromIntegral handleId) callbacks)
+  pure (IntMap.lookup (int32ToIntKey handleId) callbacks)
+
+-- | Convert Int32 to Int for use as IntMap key.
+-- Total on all GHC-supported platforms (Int >= 32 bits).
+-- Uses the total chain Int32 -> CInt -> Int.
+int32ToIntKey :: Int32 -> Int
+int32ToIntKey = CInt.toInt . Int32.toCInt
diff --git a/src/Hatter/Animation.hs b/src/Hatter/Animation.hs
index 029b7ff2..592ef0b0 100644
--- a/src/Hatter/Animation.hs
+++ b/src/Hatter/Animation.hs
@@ -31,6 +31,8 @@ import Data.List (sortBy)
 import Data.Ord (comparing)
 import Data.Time.Clock (NominalDiffTime)
 import Foreign.Ptr (Ptr)
+import Unwitch.Convert.CInt qualified as CInt
+import Unwitch.Convert.Int32 qualified as Int32
 import Hatter.Widget
   ( Keyframe(..)
   , WidgetStyle(..)
@@ -86,7 +88,7 @@ registerTween animState nodeId keyframes duration = do
         , atNodeId     = nodeId
         , atDuration   = duration
         }
-  modifyIORef' (ansTweens animState) (IntMap.insert (fromIntegral nodeId) tween)
+  modifyIORef' (ansTweens animState) (IntMap.insert (int32ToIntKey nodeId) tween)
   ensureLoopStarted animState
 
 -- | Start the platform animation loop if not already active.
@@ -255,6 +257,12 @@ interpolateStyle nodeId fromStyle toStyle progress = do
     (Just _fromEnabled, Nothing) -> pure ()
     (Nothing, Nothing) -> pure ()
 
+-- | Convert Int32 to Int for use as IntMap key.
+-- Total on all GHC-supported platforms (Int >= 32 bits).
+-- Uses the total chain Int32 -> CInt -> Int.
+int32ToIntKey :: Int32 -> Int
+int32ToIntKey = CInt.toInt . Int32.toCInt
+
 -- | FFI imports for the C animation bridge.
 foreign import ccall "animation_start_loop" c_animationStartLoop :: Ptr () -> IO ()
 foreign import ccall "animation_stop_loop"  c_animationStopLoop  :: IO ()
diff --git a/src/Hatter/AuthSession.hs b/src/Hatter/AuthSession.hs
index b91511f2..c6f0e853 100644
--- a/src/Hatter/AuthSession.hs
+++ b/src/Hatter/AuthSession.hs
@@ -36,6 +36,8 @@ import Foreign.C.String (CString, withCString)
 import Foreign.C.Types (CInt(..))
 import Foreign.Ptr (Ptr, nullPtr)
 import System.IO (hPutStrLn, stderr)
+import Unwitch.Convert.CInt qualified as CInt
+import Unwitch.Convert.Int32 qualified as Int32
 
 -- | Result of an authentication session.
 data AuthSessionResult
@@ -88,12 +90,12 @@ authSessionResultFromInt _ _                  _          = Nothing
 startAuthSession :: AuthSessionState -> Text -> Text -> (AuthSessionResult -> IO ()) -> IO ()
 startAuthSession authSessionState authUrl callbackScheme callback = do
   requestId <- readIORef (asNextId authSessionState)
-  modifyIORef' (asCallbacks authSessionState) (IntMap.insert (fromIntegral requestId) callback)
+  modifyIORef' (asCallbacks authSessionState) (IntMap.insert (int32ToIntKey requestId) callback)
   writeIORef (asNextId authSessionState) (requestId + 1)
   ctx <- readIORef (asContextPtr authSessionState)
   withCString (Text.unpack authUrl) $ \cUrl ->
     withCString (Text.unpack callbackScheme) $ \cScheme ->
-      c_authSessionStart ctx (fromIntegral requestId) cUrl cScheme
+      c_authSessionStart ctx (Int32.toCInt requestId) cUrl cScheme
 
 -- | Dispatch an auth session result from the platform back to the
 -- registered Haskell callback. Removes the callback after firing.
@@ -104,7 +106,7 @@ dispatchAuthSessionResult authSessionState requestId statusCode maybeRedirectUrl
     Nothing -> hPutStrLn stderr $
       "dispatchAuthSessionResult: unknown status code " ++ show statusCode
     Just result -> do
-      let reqKey = fromIntegral requestId
+      let reqKey = CInt.toInt requestId
       callbacks <- readIORef (asCallbacks authSessionState)
       case IntMap.lookup reqKey callbacks of
         Just callback -> do
@@ -113,6 +115,11 @@ dispatchAuthSessionResult authSessionState requestId statusCode maybeRedirectUrl
         Nothing -> hPutStrLn stderr $
           "dispatchAuthSessionResult: unknown request ID " ++ show requestId
 
+-- | Convert Int32 to Int for use as IntMap key.
+-- Total on all GHC-supported platforms (Int >= 32 bits).
+int32ToIntKey :: Int32 -> Int
+int32ToIntKey = CInt.toInt . Int32.toCInt
+
 -- | FFI import: start an auth session via the C bridge.
 foreign import ccall "auth_session_start"
   c_authSessionStart :: Ptr () -> CInt -> CString -> CString -> IO ()
diff --git a/src/Hatter/Ble.hs b/src/Hatter/Ble.hs
index 492dd7dc..9ade5254 100644
--- a/src/Hatter/Ble.hs
+++ b/src/Hatter/Ble.hs
@@ -31,6 +31,7 @@ import Foreign.C.String (CString, peekCString)
 import Foreign.C.Types (CInt(..))
 import Foreign.Ptr (Ptr, nullPtr)
 import System.IO (hPutStrLn, stderr)
+import Unwitch.Convert.CInt qualified as CInt
 
 -- | Status of the platform's BLE adapter.
 data BleAdapterStatus
@@ -136,7 +137,7 @@ dispatchBleScanResult bleState cName cAddr cRssi = do
       let scanResult = BleScanResult
             { bsrDeviceName    = nameStr
             , bsrDeviceAddress = addrStr
-            , bsrRssi          = fromIntegral cRssi
+            , bsrRssi          = CInt.toInt cRssi
             }
       callback scanResult
 
diff --git a/src/Hatter/BottomSheet.hs b/src/Hatter/BottomSheet.hs
index 0bec8e5c..9830f107 100644
--- a/src/Hatter/BottomSheet.hs
+++ b/src/Hatter/BottomSheet.hs
@@ -32,6 +32,8 @@ import Foreign.C.String (CString, withCString)
 import Foreign.C.Types (CInt(..))
 import Foreign.Ptr (Ptr, nullPtr)
 import System.IO (hPutStrLn, stderr)
+import Unwitch.Convert.CInt qualified as CInt
+import Unwitch.Convert.Int32 qualified as Int32
 
 -- | Result of a bottom sheet interaction.
 data BottomSheetAction
@@ -76,7 +78,7 @@ newBottomSheetState = do
 bottomSheetActionFromInt :: CInt -> Maybe BottomSheetAction
 bottomSheetActionFromInt (-1) = Just BottomSheetDismissed
 bottomSheetActionFromInt code
-  | code >= 0 = Just (BottomSheetItemSelected (fromIntegral code))
+  | code >= 0 = Just (BottomSheetItemSelected (CInt.toInt32 code))
   | otherwise = Nothing
 
 -- | Show a bottom sheet with the given configuration.  Registers
@@ -86,13 +88,13 @@ bottomSheetActionFromInt code
 showBottomSheet :: BottomSheetState -> BottomSheetConfig -> (BottomSheetAction -> IO ()) -> IO ()
 showBottomSheet bottomSheetState config callback = do
   requestId <- readIORef (bssNextId bottomSheetState)
-  modifyIORef' (bssCallbacks bottomSheetState) (IntMap.insert (fromIntegral requestId) callback)
+  modifyIORef' (bssCallbacks bottomSheetState) (IntMap.insert (int32ToIntKey requestId) callback)
   writeIORef (bssNextId bottomSheetState) (requestId + 1)
   ctx <- readIORef (bssContextPtr bottomSheetState)
   let joinedItems = Text.unpack (Text.intercalate "\n" (bscItems config))
   withCString (Text.unpack (bscTitle config)) $ \cTitle ->
     withCString joinedItems $ \cItems ->
-      c_bottomSheetShow ctx (fromIntegral requestId) cTitle cItems
+      c_bottomSheetShow ctx (Int32.toCInt requestId) cTitle cItems
 
 -- | Dispatch a bottom sheet result from the platform back to the
 -- registered Haskell callback.  Removes the callback after firing.
@@ -103,7 +105,7 @@ dispatchBottomSheetResult bottomSheetState requestId actionCode =
     Nothing -> hPutStrLn stderr $
       "dispatchBottomSheetResult: unknown action code " ++ show actionCode
     Just action -> do
-      let reqKey = fromIntegral requestId
+      let reqKey = CInt.toInt requestId
       callbacks <- readIORef (bssCallbacks bottomSheetState)
       case IntMap.lookup reqKey callbacks of
         Just callback -> do
@@ -112,6 +114,11 @@ dispatchBottomSheetResult bottomSheetState requestId actionCode =
         Nothing -> hPutStrLn stderr $
           "dispatchBottomSheetResult: unknown request ID " ++ show requestId
 
+-- | Convert Int32 to Int for use as IntMap key.
+-- Total on all GHC-supported platforms (Int >= 32 bits).
+int32ToIntKey :: Int32 -> Int
+int32ToIntKey = CInt.toInt . Int32.toCInt
+
 -- | FFI import: show a bottom sheet via the C bridge.
 foreign import ccall "bottom_sheet_show"
   c_bottomSheetShow :: Ptr () -> CInt -> CString -> CString -> IO ()
diff --git a/src/Hatter/Camera.hs b/src/Hatter/Camera.hs
index ee999015..b7555b0c 100644
--- a/src/Hatter/Camera.hs
+++ b/src/Hatter/Camera.hs
@@ -43,6 +43,8 @@ import Data.IntMap.Strict qualified as IntMap
 import Foreign.C.Types (CInt(..))
 import Foreign.Ptr (Ptr, nullPtr)
 import System.IO (hPutStrLn, stderr)
+import Unwitch.Convert.CInt qualified as CInt
+import Unwitch.Convert.Int32 qualified as Int32
 
 -- | Which camera to use.
 data CameraSource
@@ -130,7 +132,7 @@ cameraStatusFromInt _ = Nothing
 startCameraSession :: CameraState -> CameraSource -> IO ()
 startCameraSession cameraState source = do
   ctx <- readIORef (csContextPtr cameraState)
-  c_cameraStartSession ctx (fromIntegral (cameraSourceToInt source))
+  c_cameraStartSession ctx (Int32.toCInt (cameraSourceToInt source))
 
 -- | Stop the active camera session.
 -- Safe to call when no session is active (no-op).
@@ -144,10 +146,10 @@ stopCameraSession _cameraState =
 capturePhoto :: CameraState -> (CameraResult -> IO ()) -> IO ()
 capturePhoto cameraState callback = do
   requestId <- readIORef (csNextId cameraState)
-  modifyIORef' (csCallbacks cameraState) (IntMap.insert (fromIntegral requestId) callback)
+  modifyIORef' (csCallbacks cameraState) (IntMap.insert (int32ToIntKey requestId) callback)
   writeIORef (csNextId cameraState) (requestId + 1)
   ctx <- readIORef (csContextPtr cameraState)
-  c_cameraCapturePhoto ctx (fromIntegral requestId)
+  c_cameraCapturePhoto ctx (Int32.toCInt requestId)
 
 -- | Start recording video.  Registers three callbacks:
 --
@@ -163,13 +165,13 @@ startVideoCapture :: CameraState
                   -> IO ()
 startVideoCapture cameraState frameCallback audioCallback completionCallback = do
   requestId <- readIORef (csNextId cameraState)
-  let reqKey = fromIntegral requestId
+  let reqKey = int32ToIntKey requestId
   modifyIORef' (csCallbacks cameraState) (IntMap.insert reqKey completionCallback)
   modifyIORef' (csFrameCallbacks cameraState) (IntMap.insert reqKey frameCallback)
   modifyIORef' (csAudioCallbacks cameraState) (IntMap.insert reqKey audioCallback)
   writeIORef (csNextId cameraState) (requestId + 1)
   ctx <- readIORef (csContextPtr cameraState)
-  c_cameraStartVideo ctx (fromIntegral requestId)
+  c_cameraStartVideo ctx (Int32.toCInt requestId)
 
 -- | Stop recording video. The callback registered by 'startVideoCapture'
 -- will be fired with a completion result.
@@ -191,12 +193,12 @@ dispatchCameraResult cameraState requestId statusCode
     Nothing -> hPutStrLn stderr $
       "dispatchCameraResult: unknown status code " ++ show statusCode
     Just status -> do
-      let reqKey = fromIntegral requestId
+      let reqKey = CInt.toInt requestId
           maybePicture = case status of
             CameraSuccess -> case maybeImageData of
               Just imageBytes -> Just Picture
-                { pictureWidth  = fromIntegral imageWidth
-                , pictureHeight = fromIntegral imageHeight
+                { pictureWidth  = CInt.toInt imageWidth
+                , pictureHeight = CInt.toInt imageHeight
                 , pictureData   = imageBytes
                 }
               Nothing -> Nothing
@@ -220,10 +222,10 @@ dispatchCameraResult cameraState requestId statusCode
 -- recording stops.
 dispatchVideoFrame :: CameraState -> CInt -> ByteString -> CInt -> CInt -> IO ()
 dispatchVideoFrame cameraState requestId frameBytes frameWidth frameHeight = do
-  let reqKey = fromIntegral requestId
+  let reqKey = CInt.toInt requestId
       picture = Picture
-        { pictureWidth  = fromIntegral frameWidth
-        , pictureHeight = fromIntegral frameHeight
+        { pictureWidth  = CInt.toInt frameWidth
+        , pictureHeight = CInt.toInt frameHeight
         , pictureData   = frameBytes
         }
   frameCallbacks <- readIORef (csFrameCallbacks cameraState)
@@ -237,13 +239,18 @@ dispatchVideoFrame cameraState requestId frameBytes frameWidth frameHeight = do
 -- recording stops.
 dispatchAudioChunk :: CameraState -> CInt -> ByteString -> IO ()
 dispatchAudioChunk cameraState requestId audioBytes = do
-  let reqKey = fromIntegral requestId
+  let reqKey = CInt.toInt requestId
   audioCallbacks <- readIORef (csAudioCallbacks cameraState)
   case IntMap.lookup reqKey audioCallbacks of
     Just callback -> callback audioBytes
     Nothing -> hPutStrLn stderr $
       "dispatchAudioChunk: unknown request ID " ++ show requestId
 
+-- | Convert Int32 to Int for use as IntMap key.
+-- Total on all GHC-supported platforms (Int >= 32 bits).
+int32ToIntKey :: Int32 -> Int
+int32ToIntKey = CInt.toInt . Int32.toCInt
+
 -- | FFI import: start a camera session via the C bridge.
 foreign import ccall "camera_start_session"
   c_cameraStartSession :: Ptr () -> CInt -> IO ()
diff --git a/src/Hatter/Dialog.hs b/src/Hatter/Dialog.hs
index be80d5e8..8fc16803 100644
--- a/src/Hatter/Dialog.hs
+++ b/src/Hatter/Dialog.hs
@@ -31,6 +31,8 @@ import Foreign.C.String (CString, withCString)
 import Foreign.C.Types (CInt(..))
 import Foreign.Ptr (Ptr, nullPtr)
 import System.IO (hPutStrLn, stderr)
+import Unwitch.Convert.CInt qualified as CInt
+import Unwitch.Convert.Int32 qualified as Int32
 
 -- | Which button was tapped, or whether the dialog was dismissed.
 data DialogAction
@@ -91,7 +93,7 @@ dialogActionFromInt _ = Nothing
 showDialog :: DialogState -> DialogConfig -> (DialogAction -> IO ()) -> IO ()
 showDialog dialogState config callback = do
   requestId <- readIORef (dsNextId dialogState)
-  modifyIORef' (dsCallbacks dialogState) (IntMap.insert (fromIntegral requestId) callback)
+  modifyIORef' (dsCallbacks dialogState) (IntMap.insert (int32ToIntKey requestId) callback)
   writeIORef (dsNextId dialogState) (requestId + 1)
   ctx <- readIORef (dsContextPtr dialogState)
   withCString (Text.unpack (dcTitle config)) $ \cTitle ->
@@ -99,7 +101,7 @@ showDialog dialogState config callback = do
       withCString (Text.unpack (dcButton1 config)) $ \cButton1 ->
         withOptionalCString (dcButton2 config) $ \cButton2 ->
           withOptionalCString (dcButton3 config) $ \cButton3 ->
-            c_dialogShow ctx (fromIntegral requestId) cTitle cMessage cButton1 cButton2 cButton3
+            c_dialogShow ctx (Int32.toCInt requestId) cTitle cMessage cButton1 cButton2 cButton3
 
 -- | Dispatch a dialog result from the platform back to the
 -- registered Haskell callback.  Removes the callback after firing.
@@ -110,7 +112,7 @@ dispatchDialogResult dialogState requestId actionCode =
     Nothing -> hPutStrLn stderr $
       "dispatchDialogResult: unknown action code " ++ show actionCode
     Just action -> do
-      let reqKey = fromIntegral requestId
+      let reqKey = CInt.toInt requestId
       callbacks <- readIORef (dsCallbacks dialogState)
       case IntMap.lookup reqKey callbacks of
         Just callback -> do
@@ -124,6 +126,11 @@ withOptionalCString :: Maybe Text -> (CString -> IO a) -> IO a
 withOptionalCString Nothing  action = action nullPtr
 withOptionalCString (Just t) action = withCString (Text.unpack t) action
 
+-- | Convert Int32 to Int for use as IntMap key.
+-- Total on all GHC-supported platforms (Int >= 32 bits).
+int32ToIntKey :: Int32 -> Int
+int32ToIntKey = CInt.toInt . Int32.toCInt
+
 -- | FFI import: show a dialog via the C bridge.
 foreign import ccall "dialog_show"
   c_dialogShow :: Ptr () -> CInt -> CString -> CString -> CString -> CString -> CString -> IO ()
diff --git a/src/Hatter/Http.hs b/src/Hatter/Http.hs
index b8c70543..b592b867 100644
--- a/src/Hatter/Http.hs
+++ b/src/Hatter/Http.hs
@@ -43,6 +43,9 @@ import Foreign.C.String (CString, withCString)
 import Foreign.C.Types (CInt(..))
 import Foreign.Ptr (Ptr, nullPtr)
 import System.IO (hPutStrLn, stderr)
+import Unwitch.Convert.CInt qualified as CInt
+import Unwitch.Convert.Int qualified as Int
+import Unwitch.Convert.Int32 qualified as Int32
 
 -- | HTTP request method.
 data HttpMethod
@@ -128,7 +131,7 @@ parseHeaders headerText =
 performRequest :: HttpState -> HttpRequest -> (Either HttpError HttpResponse -> IO ()) -> IO ()
 performRequest httpState request callback = do
   requestId <- readIORef (hsNextId httpState)
-  modifyIORef' (hsCallbacks httpState) (IntMap.insert (fromIntegral requestId) callback)
+  modifyIORef' (hsCallbacks httpState) (IntMap.insert (int32ToIntKey requestId) callback)
   writeIORef (hsNextId httpState) (requestId + 1)
   ctx <- readIORef (hsContextPtr httpState)
   let methodInt = httpMethodToInt (hrMethod request)
@@ -136,22 +139,22 @@ performRequest httpState request callback = do
   withCString (Text.unpack (hrUrl request)) $ \cUrl ->
     withCString headerStr $ \cHeaders ->
       BS.useAsCStringLen (hrBody request) $ \(cBody, bodyLen) ->
-        c_httpRequest ctx (fromIntegral requestId) methodInt
-                      cUrl cHeaders cBody (fromIntegral bodyLen)
+        c_httpRequest ctx (Int32.toCInt requestId) methodInt
+                      cUrl cHeaders cBody (maybe 0 id (Int.toCInt bodyLen))
 
 -- | Dispatch an HTTP result from the platform back to the registered
 -- Haskell callback. Removes the callback after firing.
 -- Unknown request IDs or result codes are silently logged to stderr.
 dispatchHttpResult :: HttpState -> CInt -> CInt -> CInt -> Maybe Text -> ByteString -> IO ()
 dispatchHttpResult httpState requestId resultCode httpStatus maybeHeaders responseBody = do
-  let reqKey = fromIntegral requestId
+  let reqKey = CInt.toInt requestId
   callbacks <- readIORef (hsCallbacks httpState)
   case IntMap.lookup reqKey callbacks of
     Just callback -> do
       modifyIORef' (hsCallbacks httpState) (IntMap.delete reqKey)
       let result = case resultCode of
             0 -> Right HttpResponse
-              { hrStatusCode  = fromIntegral httpStatus
+              { hrStatusCode  = CInt.toInt httpStatus
               , hrRespHeaders = maybe [] parseHeaders maybeHeaders
               , hrRespBody    = responseBody
               }
@@ -162,6 +165,11 @@ dispatchHttpResult httpState requestId resultCode httpStatus maybeHeaders respon
     Nothing -> hPutStrLn stderr $
       "dispatchHttpResult: unknown request ID " ++ show requestId
 
+-- | Convert Int32 to Int for use as IntMap key.
+-- Total on all GHC-supported platforms (Int >= 32 bits).
+int32ToIntKey :: Int32 -> Int
+int32ToIntKey = CInt.toInt . Int32.toCInt
+
 -- | FFI import: send an HTTP request via the C bridge.
 foreign import ccall "http_request"
   c_httpRequest :: Ptr () -> CInt -> CInt -> CString -> CString
diff --git a/src/Hatter/Permission.hs b/src/Hatter/Permission.hs
index 73d49aca..e6112493 100644
--- a/src/Hatter/Permission.hs
+++ b/src/Hatter/Permission.hs
@@ -29,6 +29,8 @@ import Data.IntMap.Strict qualified as IntMap
 import Foreign.C.Types (CInt(..))
 import Foreign.Ptr (Ptr, nullPtr)
 import System.IO (hPutStrLn, stderr)
+import Unwitch.Convert.CInt qualified as CInt
+import Unwitch.Convert.Int32 qualified as Int32
 
 -- | Dangerous permissions that require runtime consent on mobile.
 data Permission
@@ -98,10 +100,10 @@ permissionStatusFromInt _ = Nothing
 requestPermission :: PermissionState -> Permission -> (PermissionStatus -> IO ()) -> IO ()
 requestPermission permissionState permission callback = do
   requestId <- readIORef (psNextId permissionState)
-  modifyIORef' (psCallbacks permissionState) (IntMap.insert (fromIntegral requestId) callback)
+  modifyIORef' (psCallbacks permissionState) (IntMap.insert (int32ToIntKey requestId) callback)
   writeIORef (psNextId permissionState) (requestId + 1)
   ctx <- readIORef (psContextPtr permissionState)
-  c_permissionRequest ctx (permissionToInt permission) (fromIntegral requestId)
+  c_permissionRequest ctx (permissionToInt permission) (Int32.toCInt requestId)
 
 -- | Check whether a permission is currently granted (synchronous).
 checkPermission :: Permission -> IO PermissionStatus
@@ -123,13 +125,18 @@ dispatchPermissionResult permissionState requestId statusCode =
       "dispatchPermissionResult: unknown status code " ++ show statusCode
     Just status -> do
       callbacks <- readIORef (psCallbacks permissionState)
-      case IntMap.lookup (fromIntegral requestId) callbacks of
+      case IntMap.lookup (CInt.toInt requestId) callbacks of
         Nothing -> hPutStrLn stderr $
           "dispatchPermissionResult: unknown request ID " ++ show requestId
         Just callback -> do
-          modifyIORef' (psCallbacks permissionState) (IntMap.delete (fromIntegral requestId))
+          modifyIORef' (psCallbacks permissionState) (IntMap.delete (CInt.toInt requestId))
           callback status
 
+-- | Convert Int32 to Int for use as IntMap key.
+-- Total on all GHC-supported platforms (Int >= 32 bits).
+int32ToIntKey :: Int32 -> Int
+int32ToIntKey = CInt.toInt . Int32.toCInt
+
 -- | FFI import: request a permission via the C bridge.
 -- Takes an opaque context pointer, permission code, and request ID.
 foreign import ccall "permission_request"
diff --git a/src/Hatter/PlatformSignIn.hs b/src/Hatter/PlatformSignIn.hs
index a878ea1b..ef23a2f1 100644
--- a/src/Hatter/PlatformSignIn.hs
+++ b/src/Hatter/PlatformSignIn.hs
@@ -35,6 +35,8 @@ import Data.Text (Text)
 import Foreign.C.Types (CInt(..))
 import Foreign.Ptr (Ptr, nullPtr)
 import System.IO (hPutStrLn, stderr)
+import Unwitch.Convert.CInt qualified as CInt
+import Unwitch.Convert.Int32 qualified as Int32
 
 -- | Identity provider for platform sign-in.
 data SignInProvider
@@ -126,10 +128,10 @@ signInResultFromInt _ _ _ _ _ _ = Nothing
 startPlatformSignIn :: PlatformSignInState -> SignInProvider -> (SignInResult -> IO ()) -> IO ()
 startPlatformSignIn signInState provider callback = do
   requestId <- readIORef (psiNextId signInState)
-  modifyIORef' (psiCallbacks signInState) (IntMap.insert (fromIntegral requestId) callback)
+  modifyIORef' (psiCallbacks signInState) (IntMap.insert (int32ToIntKey requestId) callback)
   writeIORef (psiNextId signInState) (requestId + 1)
   ctx <- readIORef (psiContextPtr signInState)
-  c_platformSignInStart ctx (fromIntegral requestId) (providerToInt provider)
+  c_platformSignInStart ctx (Int32.toCInt requestId) (providerToInt provider)
 
 -- | Dispatch a platform sign-in result from the platform back to the
 -- registered Haskell callback. Removes the callback after firing.
@@ -140,7 +142,7 @@ dispatchPlatformSignInResult signInState requestId statusCode maybeToken maybeUs
     Nothing -> hPutStrLn stderr $
       "dispatchPlatformSignInResult: unknown status code " ++ show statusCode
     Just result -> do
-      let reqKey = fromIntegral requestId
+      let reqKey = CInt.toInt requestId
       callbacks <- readIORef (psiCallbacks signInState)
       case IntMap.lookup reqKey callbacks of
         Just callback -> do
@@ -149,6 +151,11 @@ dispatchPlatformSignInResult signInState requestId statusCode maybeToken maybeUs
         Nothing -> hPutStrLn stderr $
           "dispatchPlatformSignInResult: unknown request ID " ++ show requestId
 
+-- | Convert Int32 to Int for use as IntMap key.
+-- Total on all GHC-supported platforms (Int >= 32 bits).
+int32ToIntKey :: Int32 -> Int
+int32ToIntKey = CInt.toInt . Int32.toCInt
+
 -- | FFI import: start a platform sign-in via the C bridge.
 foreign import ccall "platform_sign_in_start"
   c_platformSignInStart :: Ptr () -> CInt -> CInt -> IO ()
diff --git a/src/Hatter/Render.hs b/src/Hatter/Render.hs
index 80a2e89a..e2772411 100644
--- a/src/Hatter/Render.hs
+++ b/src/Hatter/Render.hs
@@ -31,6 +31,7 @@ import Data.Text (Text, pack)
 import Hatter.Action (Action(..), ActionState, OnChange(..), lookupAction, lookupTextAction)
 import Data.List (sortBy)
 import Data.Ord (comparing)
+import Unwitch.Convert.Int32 qualified as Int32
 import Hatter.Animation (AnimationState, registerTween)
 import Hatter.Widget (AnimatedConfig(..), ButtonConfig(..), FontConfig(..), ImageConfig(..), ImageSource(..), InputType(..), Keyframe(..), LayoutItem(..), LayoutSettings(..), MapViewConfig(..), ResourceName(..), ScaleType(..), TextAlignment(..), TextConfig(..), TextInputConfig(..), WebViewConfig(..), Widget(..), WidgetStyle(..), colorToHex, normalizeAnimated, resolveKeyAtIndex)
 
@@ -192,7 +193,7 @@ createRenderedNode _animState widget@(TextInput config) = do
   nodeId <- Bridge.createNode Bridge.NodeTextInput
   Bridge.setStrProp nodeId Bridge.PropText (tiValue config)
   Bridge.setStrProp nodeId Bridge.PropHint (tiHint config)
-  Bridge.setNumProp nodeId Bridge.PropInputType (fromIntegral (inputTypeToInt (tiInputType config)))
+  Bridge.setNumProp nodeId Bridge.PropInputType (Int32.toDouble (inputTypeToInt (tiInputType config)))
   Bridge.setHandler nodeId Bridge.EventTextChange (onChangeId (tiOnChange config))
   applyFontConfig nodeId (tiFontConfig config)
   when (tiAutoFocus config) $
@@ -437,7 +438,7 @@ diffRenderNode _animState (Just (RenderedLeaf (TextInput oldConfig) nodeId)) new
     else pure ()
   if tiInputType oldConfig /= tiInputType newConfig
     then Bridge.setNumProp nodeId Bridge.PropInputType
-           (fromIntegral (inputTypeToInt (tiInputType newConfig)))
+           (Int32.toDouble (inputTypeToInt (tiInputType newConfig)))
     else pure ()
   if onChangeId (tiOnChange oldConfig) /= onChangeId (tiOnChange newConfig)
     then Bridge.setHandler nodeId Bridge.EventTextChange
diff --git a/src/Hatter/SecureStorage.hs b/src/Hatter/SecureStorage.hs
index 2ddf8da7..4998ba68 100644
--- a/src/Hatter/SecureStorage.hs
+++ b/src/Hatter/SecureStorage.hs
@@ -32,6 +32,8 @@ import Foreign.C.String (CString, withCString)
 import Foreign.C.Types (CInt(..))
 import Foreign.Ptr (Ptr, nullPtr)
 import System.IO (hPutStrLn, stderr)
+import Unwitch.Convert.CInt qualified as CInt
+import Unwitch.Convert.Int32 qualified as Int32
 
 -- | Result of a secure storage operation.
 data SecureStorageStatus
@@ -89,12 +91,12 @@ storageStatusFromInt _ = Nothing
 secureStorageWrite :: SecureStorageState -> Text -> Text -> (SecureStorageStatus -> IO ()) -> IO ()
 secureStorageWrite storageState key value callback = do
   requestId <- readIORef (ssNextId storageState)
-  modifyIORef' (ssWriteCallbacks storageState) (IntMap.insert (fromIntegral requestId) callback)
+  modifyIORef' (ssWriteCallbacks storageState) (IntMap.insert (int32ToIntKey requestId) callback)
   writeIORef (ssNextId storageState) (requestId + 1)
   ctx <- readIORef (ssContextPtr storageState)
   withCString (Text.unpack key) $ \cKey ->
     withCString (Text.unpack value) $ \cValue ->
-      c_secureStorageWrite ctx (fromIntegral requestId) cKey cValue
+      c_secureStorageWrite ctx (Int32.toCInt requestId) cKey cValue
 
 -- | Read a value from secure storage by key.  Registers @callback@ and
 -- calls the C bridge.  The callback receives the status and an optional
@@ -102,22 +104,22 @@ secureStorageWrite storageState key value callback = do
 secureStorageRead :: SecureStorageState -> Text -> (SecureStorageStatus -> Maybe Text -> IO ()) -> IO ()
 secureStorageRead storageState key callback = do
   requestId <- readIORef (ssNextId storageState)
-  modifyIORef' (ssReadCallbacks storageState) (IntMap.insert (fromIntegral requestId) callback)
+  modifyIORef' (ssReadCallbacks storageState) (IntMap.insert (int32ToIntKey requestId) callback)
   writeIORef (ssNextId storageState) (requestId + 1)
   ctx <- readIORef (ssContextPtr storageState)
   withCString (Text.unpack key) $ \cKey ->
-    c_secureStorageRead ctx (fromIntegral requestId) cKey
+    c_secureStorageRead ctx (Int32.toCInt requestId) cKey
 
 -- | Delete a key from secure storage.  Registers @callback@ and calls
 -- the C bridge.  The callback fires when the platform responds.
 secureStorageDelete :: SecureStorageState -> Text -> (SecureStorageStatus -> IO ()) -> IO ()
 secureStorageDelete storageState key callback = do
   requestId <- readIORef (ssNextId storageState)
-  modifyIORef' (ssDeleteCallbacks storageState) (IntMap.insert (fromIntegral requestId) callback)
+  modifyIORef' (ssDeleteCallbacks storageState) (IntMap.insert (int32ToIntKey requestId) callback)
   writeIORef (ssNextId storageState) (requestId + 1)
   ctx <- readIORef (ssContextPtr storageState)
   withCString (Text.unpack key) $ \cKey ->
-    c_secureStorageDelete ctx (fromIntegral requestId) cKey
+    c_secureStorageDelete ctx (Int32.toCInt requestId) cKey
 
 -- | Dispatch a secure storage result from the platform back to the
 -- registered Haskell callback.  Tries write callbacks first, then read,
@@ -129,7 +131,7 @@ dispatchSecureStorageResult storageState requestId statusCode maybeValue =
     Nothing -> hPutStrLn stderr $
       "dispatchSecureStorageResult: unknown status code " ++ show statusCode
     Just status -> do
-      let reqKey = fromIntegral requestId
+      let reqKey = CInt.toInt requestId
       -- Try write callbacks
       writeCallbacks <- readIORef (ssWriteCallbacks storageState)
       case IntMap.lookup reqKey writeCallbacks of
@@ -156,6 +158,11 @@ dispatchSecureStorageResult storageState requestId statusCode maybeValue =
                 Nothing -> hPutStrLn stderr $
                   "dispatchSecureStorageResult: unknown request ID " ++ show requestId
 
+-- | Convert Int32 to Int for use as IntMap key.
+-- Total on all GHC-supported platforms (Int >= 32 bits).
+int32ToIntKey :: Int32 -> Int
+int32ToIntKey = CInt.toInt . Int32.toCInt
+
 -- | FFI import: write a key-value pair via the C bridge.
 foreign import ccall "secure_storage_write"
   c_secureStorageWrite :: Ptr () -> CInt -> CString -> CString -> IO ()
diff --git a/src/Hatter/UIBridge.hs b/src/Hatter/UIBridge.hs
index 04865d32..9ee6045f 100644
--- a/src/Hatter/UIBridge.hs
+++ b/src/Hatter/UIBridge.hs
@@ -31,6 +31,9 @@ import Data.Word (Word8)
 import Foreign.C.String (CString, withCString)
 import Foreign.C.Types (CInt(..), CDouble(..))
 import Foreign.Ptr (Ptr, castPtr)
+import Unwitch.Convert.Int qualified as Int
+import Unwitch.Convert.Int32 qualified as Int32
+import Unwitch.Convert.CInt qualified as CInt
 
 -- | Widget node types corresponding to @UI_NODE_*@ in @UIBridge.h@.
 data NodeType
@@ -133,50 +136,50 @@ foreign import ccall "ui_clear"          c_clear        :: IO ()
 
 -- | Create a native node of the given type. Returns an opaque node ID.
 createNode :: NodeType -> IO Int32
-createNode nt = fromIntegral <$> c_createNode (fromIntegral (nodeTypeToInt nt))
+createNode nt = CInt.toInt32 <$> c_createNode (Int32.toCInt (nodeTypeToInt nt))
 
 -- | Set a string property on a node.
 setStrProp :: Int32 -> PropId -> Text -> IO ()
 setStrProp nodeId propId value =
   withCString (unpack value) $ \cstr ->
-    c_setStrProp (fromIntegral nodeId) (fromIntegral (propIdToInt propId)) cstr
+    c_setStrProp (Int32.toCInt nodeId) (Int32.toCInt (propIdToInt propId)) cstr
 
 -- | Set a numeric property on a node.
 setNumProp :: Int32 -> PropId -> Double -> IO ()
 setNumProp nodeId propId value =
-  c_setNumProp (fromIntegral nodeId) (fromIntegral (propIdToInt propId)) (realToFrac value)
+  c_setNumProp (Int32.toCInt nodeId) (Int32.toCInt (propIdToInt propId)) (realToFrac value)
 
 -- | Set raw image data (PNG/JPEG bytes) on a node.
 setImageData :: Int32 -> ByteString -> IO ()
 setImageData nodeId imageBytes =
   BS.useAsCStringLen imageBytes $ \(ptr, len) ->
-    c_setImageData (fromIntegral nodeId) (castPtr ptr) (fromIntegral len)
+    c_setImageData (Int32.toCInt nodeId) (castPtr ptr) (maybe 0 id (Int.toCInt len))
 
 -- | Register an event handler on a node. The @callbackId@ is looked up
 -- in the 'RenderState' callback registry when the event fires.
 setHandler :: Int32 -> EventType -> Int32 -> IO ()
 setHandler nodeId eventType callbackId =
-  c_setHandler (fromIntegral nodeId) (fromIntegral (eventTypeToInt eventType)) (fromIntegral callbackId)
+  c_setHandler (Int32.toCInt nodeId) (Int32.toCInt (eventTypeToInt eventType)) (Int32.toCInt callbackId)
 
 -- | Add a child node to a parent container.
 addChild :: Int32 -> Int32 -> IO ()
 addChild parentId childId =
-  c_addChild (fromIntegral parentId) (fromIntegral childId)
+  c_addChild (Int32.toCInt parentId) (Int32.toCInt childId)
 
 -- | Remove a child node from a parent container.
 removeChild :: Int32 -> Int32 -> IO ()
 removeChild parentId childId =
-  c_removeChild (fromIntegral parentId) (fromIntegral childId)
+  c_removeChild (Int32.toCInt parentId) (Int32.toCInt childId)
 
 -- | Destroy a node and free its native resources.
 destroyNode :: Int32 -> IO ()
 destroyNode nodeId =
-  c_destroyNode (fromIntegral nodeId)
+  c_destroyNode (Int32.toCInt nodeId)
 
 -- | Set a node as the root of the display.
 setRoot :: Int32 -> IO ()
 setRoot nodeId =
-  c_setRoot (fromIntegral nodeId)
+  c_setRoot (Int32.toCInt nodeId)
 
 -- | Clear all nodes (called before re-render).
 clear :: IO ()
diff --git a/src/Hatter/Widget.hs b/src/Hatter/Widget.hs
index 63d2ffff..bef08704 100644
--- a/src/Hatter/Widget.hs
+++ b/src/Hatter/Widget.hs
@@ -73,6 +73,8 @@ import Data.Text qualified as Text
 import Data.Time.Clock (NominalDiffTime)
 import Data.Word (Word8)
 import Hatter.Action (Action, OnChange)
+import Unwitch.Convert.Int qualified as Int
+import Unwitch.Convert.Word8 qualified as Word8
 
 -- | Font configuration for text-bearing widgets.
 -- Only 'Text', 'Button', and 'TextInput' can carry a 'FontConfig'.
@@ -149,7 +151,7 @@ colorFromText raw = do
   if all isHexDigit hex
     then case hex of
       [r1, g1, b1] ->
-        let expand ch = let val = digitToInt ch in fromIntegral (val * 16 + val)
+        let expand ch = let val = digitToInt ch in maybe 0 id (Int.toWord8 (val * 16 + val))
         in Just (Color (expand r1) (expand g1) (expand b1) 255)
       [r1, r2, g1, g2, b1, b2] ->
         Just (Color (hexByte r1 r2) (hexByte g1 g2) (hexByte b1 b2) 255)
@@ -160,14 +162,14 @@ colorFromText raw = do
 
 -- | Convert two hex characters to a Word8.
 hexByte :: Char -> Char -> Word8
-hexByte high low = fromIntegral (digitToInt high * 16 + digitToInt low)
+hexByte high low = maybe 0 id (Int.toWord8 (digitToInt high * 16 + digitToInt low))
 
 -- | Convert a 'Color' to a hex string in @"#AARRGGBB"@ format for the C bridge.
 colorToHex :: Color -> Text
 colorToHex (Color r g b a) = Text.pack ('#' : toHexByte a ++ toHexByte r ++ toHexByte g ++ toHexByte b)
   where
     toHexByte :: Word8 -> String
-    toHexByte byte = [intToDigit (fromIntegral byte `div` 16), intToDigit (fromIntegral byte `mod` 16)]
+    toHexByte byte = [intToDigit (Word8.toInt byte `div` 16), intToDigit (Word8.toInt byte `mod` 16)]
 
 -- | Visual style overrides for a widget node.
 -- Font size is not here — it belongs in the config records of
@@ -367,7 +369,7 @@ andThen first second = AnimatedConfig
 -- | Linearly interpolate a single 'Word8' channel.
 lerpWord8 :: Word8 -> Word8 -> Double -> Word8
 lerpWord8 from to progress =
-  round (fromIntegral from + (fromIntegral to - fromIntegral from) * progress :: Double)
+  round (Word8.toDouble from + (Word8.toDouble to - Word8.toDouble from) * progress :: Double)
 
 -- | Interpolate between two colors by lerping each RGBA channel.
 interpolateColor :: Color -> Color -> Double -> Color
diff --git a/test/RedrawDemoMain.hs b/test/RedrawDemoMain.hs
index b87c46e8..9f0f2526 100644
--- a/test/RedrawDemoMain.hs
+++ b/test/RedrawDemoMain.hs
@@ -15,6 +15,7 @@ import Data.IORef (IORef, newIORef, readIORef, writeIORef)
 import Data.Text (pack)
 import Foreign.C.Types (CInt(..))
 import Foreign.Ptr (Ptr)
+import Unwitch.Convert.CInt qualified as CInt
 import Hatter
   ( MobileApp(..)
   , UserState(..)
@@ -59,8 +60,8 @@ redrawView startedRef _userState = do
     -- Start C-level timer: 3 ticks, 3 seconds apart.
     -- The context was stored by redraw_store_ctx() in renderView.
     c_startPeriodicRedraw 3 3
-  count <- fromIntegral <$> c_getPeriodicCounter
-  platformLog ("view rebuilt: count=" <> pack (show (count :: Int)))
+  count <- CInt.toInt <$> c_getPeriodicCounter
+  platformLog ("view rebuilt: count=" <> pack (show count))
   pure $ column [Text TextConfig
     { tcLabel = "Count: " <> pack (show count)
     , tcFontConfig = Nothing
diff --git a/test/Test/AppContextTests.hs b/test/Test/AppContextTests.hs
index 012601d7..9e39840b 100644
--- a/test/Test/AppContextTests.hs
+++ b/test/Test/AppContextTests.hs
@@ -24,6 +24,7 @@ import Hatter
   , haskellOnLifecycle
   )
 import Hatter.AppContext (AppContext(..), newAppContext, freeAppContext, derefAppContext)
+import Unwitch.Convert.Int32 qualified as Int32
 import Hatter.Lifecycle
   ( LifecycleEvent(..)
   , MobileContext(..)
@@ -203,7 +204,7 @@ exceptionHandlerTests = testGroup "ExceptionHandler"
       -- First render to register the button callback
       haskellRenderUI ctxPtr
       -- Dispatch the button, which throws — handler overwrites view
-      haskellOnUIEvent ctxPtr (fromIntegral (actionId crashHandle))
+      haskellOnUIEvent ctxPtr (Int32.toCInt (actionId crashHandle))
       isError <- viewIsErrorWidget ctxPtr
       assertBool "view should be error widget after button callback exception" isError
       freeAppContext ctxPtr
@@ -232,7 +233,7 @@ exceptionHandlerTests = testGroup "ExceptionHandler"
       -- Dispatch the dismiss action (pre-registered during newAppContext).
       appCtx <- derefAppContext ctxPtr
       let dismissId = actionId (acDismissAction appCtx)
-      haskellOnUIEvent ctxPtr (fromIntegral dismissId)
+      haskellOnUIEvent ctxPtr (Int32.toCInt dismissId)
       isStillError <- viewIsErrorWidget ctxPtr
       assertBool "should no longer show error widget after dismiss" (not isStillError)
       freeAppContext ctxPtr

From d1298bc1d645439abe65c46129e94f33f75a3534 Mon Sep 17 00:00:00 2001
From: jappeace-sloth <sloth@jappie.me>
Date: Sun, 19 Apr 2026 19:02:27 +0000
Subject: [PATCH 2/5] Add unwitch override to ios-deps.nix for iOS/watchOS
 builds

iOS and watchOS use ios-deps.nix (native macOS GHC) rather than
cross-deps.nix (Android cross-GHC). The unwitch package was missing
from the iOS/watchOS haskellPackages overlay, causing "Could not find
module Unwitch.Convert.*" errors in CI.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 nix/ios-deps.nix | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/nix/ios-deps.nix b/nix/ios-deps.nix
index 48fc56ef..68793672 100644
--- a/nix/ios-deps.nix
+++ b/nix/ios-deps.nix
@@ -18,8 +18,15 @@
 let
   pkgs = import sources.nixpkgs {};
 
+  unwitchOverride = self: super: {
+    unwitch = self.callCabal2nix "unwitch" (builtins.fetchTarball {
+      url = "https://hackage.haskell.org/package/unwitch-2.2.0/unwitch-2.2.0.tar.gz";
+      sha256 = "sha256:he/wdUN1XOcEo0VTmJVRrdQnGmZldxgCPCxlSDvzd9c=";
+    }) {};
+  };
+
   nativeHaskellPkgs = pkgs.haskellPackages.override {
-    overrides = hpkgs;
+    overrides = pkgs.lib.composeExtensions unwitchOverride hpkgs;
   };
 
   ghc = nativeHaskellPkgs.ghc;

From bbb9c4326ce82e3e5b472869293228a57f829d58 Mon Sep 17 00:00:00 2001
From: jappeace-sloth <sloth@jappie.me>
Date: Sun, 19 Apr 2026 19:07:32 +0000
Subject: [PATCH 3/5] Include hatter's own non-boot deps in ios-deps.nix

mkIOSLib compiles hatter with raw ghc -staticlib, not through cabal,
so its non-boot dependencies must be explicitly provided in the
crossDeps package DB. Before unwitch, hatter only used GHC boot
packages (base, containers, text, etc.). Now it also needs unwitch.

Add hatterOwnDeps list to ios-deps.nix so the unwitch .a/.hi/.conf
are collected even when no consumerCabalFile is provided (as in CI).
This fixes iOS and watchOS builds which both use ios-deps.nix.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 nix/ios-deps.nix | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/nix/ios-deps.nix b/nix/ios-deps.nix
index 68793672..d167f837 100644
--- a/nix/ios-deps.nix
+++ b/nix/ios-deps.nix
@@ -37,7 +37,11 @@ let
     haskellPkgs = nativeHaskellPkgs;
   };
 
+  # Hatter's own non-boot dependencies — always included so mkIOSLib's
+  # raw GHC invocation can find them even without a consumer cabal file.
+  hatterOwnDeps = [ nativeHaskellPkgs.unwitch ];
+
 in import ./collect-deps.nix {
   inherit pkgs ghc ghcPkgCmd;
-  deps = resolvedDeps;
+  deps = resolvedDeps ++ hatterOwnDeps;
 }

From 43b63c6f1f3112db743429f113d9036468a5779b Mon Sep 17 00:00:00 2001
From: jappeace-sloth <sloth@jappie.me>
Date: Sun, 19 Apr 2026 19:25:28 +0000
Subject: [PATCH 4/5] Collect unwitch in cross-deps.nix for Android builds
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

collect-deps.nix only processes packages explicitly in its deps list —
it doesn't follow propagatedBuildInputs. Since hatter's .conf now
references unwitch, unwitch's .a and .conf must also be collected.

Without this, Android builds fail with "unusable due to missing
dependencies: unwitch-2.2.0-..." when importing Hatter.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 nix/cross-deps.nix | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/nix/cross-deps.nix b/nix/cross-deps.nix
index 13aa5e96..48dad8b2 100644
--- a/nix/cross-deps.nix
+++ b/nix/cross-deps.nix
@@ -292,9 +292,13 @@ WRAPPER
   # so its .a and .conf are available for linking.
   hatterDep = if hatterSrc != null then [ crossHaskellPkgs.hatter ] else [];
 
+  # Hatter's own non-boot dependencies — must be collected so hatter's
+  # .conf can resolve them (collect-deps doesn't follow propagatedBuildInputs).
+  hatterOwnDeps = [ crossHaskellPkgs.unwitch ];
+
 in import ./collect-deps.nix {
   inherit pkgs ghc ghcPkgCmd;
-  deps = resolvedDeps ++ hatterDep;
+  deps = resolvedDeps ++ hatterDep ++ hatterOwnDeps;
   mainLibPnames = if hatterSrc != null then [ "hatter" ] else [];
   iservProxy = iservWrapper;
 }

From b85af206af51c0b154dd01fe89cfe9b4504ae056 Mon Sep 17 00:00:00 2001
From: jappeace-sloth <sloth@jappie.me>
Date: Mon, 20 Apr 2026 19:20:13 +0000
Subject: [PATCH 5/5] Simplify Int32->Int conversions with unwitch 3.0.0

unwitch 3.0.0 makes Int32.toInt total (Int32 -> Int) on GHC, so
the int32ToIntKey helper and CInt.toInt . Int32.toCInt chain are
no longer needed. Replace all 10 copies with direct Int32.toInt
calls and remove the CInt import from files that only used it for
the helper.

Bump unwitch dependency to >= 3.0.0, point nix overlays to the
jappeace/unwitch commit with the total conversion.

Prompt: go simplify conversions here with unwitch 3

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 hatter.cabal                 |  6 +++---
 nix/cross-deps.nix           |  4 ++--
 nix/hpkgs.nix                |  4 ++--
 nix/ios-deps.nix             |  4 ++--
 src/Hatter/Action.hs         | 15 ++++-----------
 src/Hatter/Animation.hs      |  9 +--------
 src/Hatter/AuthSession.hs    |  7 +------
 src/Hatter/BottomSheet.hs    |  7 +------
 src/Hatter/Camera.hs         |  9 ++-------
 src/Hatter/Dialog.hs         |  7 +------
 src/Hatter/Http.hs           |  7 +------
 src/Hatter/Permission.hs     |  7 +------
 src/Hatter/PlatformSignIn.hs |  7 +------
 src/Hatter/SecureStorage.hs  | 11 +++--------
 14 files changed, 25 insertions(+), 79 deletions(-)

diff --git a/hatter.cabal b/hatter.cabal
index d5a3e87a..c5d180fa 100644
--- a/hatter.cabal
+++ b/hatter.cabal
@@ -120,7 +120,7 @@ library
       bytestring < 1,
       transformers < 0.7,
       time,
-      unwitch >= 2.2.0 && < 3
+      unwitch >= 3.0.0 && < 4
   c-sources:
       cbits/android_stubs.c
       cbits/platform_log.c
@@ -193,7 +193,7 @@ executable redraw-demo
   build-depends:
       hatter,
       text,
-      unwitch >= 2.2.0 && < 3
+      unwitch >= 3.0.0 && < 4
 
 executable confetti-repro-demo
   import: common-options
@@ -253,4 +253,4 @@ test-suite unit
       bytestring,
       directory,
       filepath,
-      unwitch >= 2.2.0 && < 3
+      unwitch >= 3.0.0 && < 4
diff --git a/nix/cross-deps.nix b/nix/cross-deps.nix
index 48dad8b2..0a0570c2 100644
--- a/nix/cross-deps.nix
+++ b/nix/cross-deps.nix
@@ -230,8 +230,8 @@ WRAPPER
 
   unwitchOverride = self: super: {
     unwitch = self.callCabal2nix "unwitch" (builtins.fetchTarball {
-      url = "https://hackage.haskell.org/package/unwitch-2.2.0/unwitch-2.2.0.tar.gz";
-      sha256 = "sha256:he/wdUN1XOcEo0VTmJVRrdQnGmZldxgCPCxlSDvzd9c=";
+      url = "https://github.com/jappeace/unwitch/archive/2759bdd153f293e0e6524d0170e861e51302caa4.tar.gz";
+      sha256 = "sha256:BGxZ1CQGIYP/gg/J9jua2/wSEH4qq7bW91qooNELUlI=";
     }) {};
   };
 
diff --git a/nix/hpkgs.nix b/nix/hpkgs.nix
index a9d5bf6c..5eec64a5 100644
--- a/nix/hpkgs.nix
+++ b/nix/hpkgs.nix
@@ -10,8 +10,8 @@ pkgs.haskellPackages.override {
     # bigger projects should consider putting haskell stuff in a subfolder
     hatter-project = hnew.callCabal2nix "hatter" ../. { };
     unwitch = hnew.callCabal2nix "unwitch" (builtins.fetchTarball {
-      url = "https://hackage.haskell.org/package/unwitch-2.2.0/unwitch-2.2.0.tar.gz";
-      sha256 = "sha256:he/wdUN1XOcEo0VTmJVRrdQnGmZldxgCPCxlSDvzd9c=";
+      url = "https://github.com/jappeace/unwitch/archive/2759bdd153f293e0e6524d0170e861e51302caa4.tar.gz";
+      sha256 = "sha256:BGxZ1CQGIYP/gg/J9jua2/wSEH4qq7bW91qooNELUlI=";
     }) {};
   };
 }
diff --git a/nix/ios-deps.nix b/nix/ios-deps.nix
index d167f837..9247fb80 100644
--- a/nix/ios-deps.nix
+++ b/nix/ios-deps.nix
@@ -20,8 +20,8 @@ let
 
   unwitchOverride = self: super: {
     unwitch = self.callCabal2nix "unwitch" (builtins.fetchTarball {
-      url = "https://hackage.haskell.org/package/unwitch-2.2.0/unwitch-2.2.0.tar.gz";
-      sha256 = "sha256:he/wdUN1XOcEo0VTmJVRrdQnGmZldxgCPCxlSDvzd9c=";
+      url = "https://github.com/jappeace/unwitch/archive/2759bdd153f293e0e6524d0170e861e51302caa4.tar.gz";
+      sha256 = "sha256:BGxZ1CQGIYP/gg/J9jua2/wSEH4qq7bW91qooNELUlI=";
     }) {};
   };
 
diff --git a/src/Hatter/Action.hs b/src/Hatter/Action.hs
index 7278f6af..41d9f6b4 100644
--- a/src/Hatter/Action.hs
+++ b/src/Hatter/Action.hs
@@ -40,7 +40,6 @@ import Data.Int (Int32)
 import Data.IntMap.Strict (IntMap)
 import Data.IntMap.Strict qualified as IntMap
 import Data.Text (Text)
-import Unwitch.Convert.CInt qualified as CInt
 import Unwitch.Convert.Int32 qualified as Int32
 
 -- | An opaque handle to a click / tap callback.
@@ -88,7 +87,7 @@ newtype ActionM a = ActionM (ActionState -> IO a)
 createAction :: IO () -> ActionM Action
 createAction callback = ActionM $ \state -> do
   handleId <- readIORef (asNextId state)
-  modifyIORef' (asCallbacks state) (IntMap.insert (int32ToIntKey handleId) callback)
+  modifyIORef' (asCallbacks state) (IntMap.insert (Int32.toInt handleId) callback)
   modifyIORef' (asNextId state) (+ 1)
   pure (Action handleId)
 
@@ -96,7 +95,7 @@ createAction callback = ActionM $ \state -> do
 createOnChange :: (Text -> IO ()) -> ActionM OnChange
 createOnChange callback = ActionM $ \state -> do
   handleId <- readIORef (asNextId state)
-  modifyIORef' (asTextCallbacks state) (IntMap.insert (int32ToIntKey handleId) callback)
+  modifyIORef' (asTextCallbacks state) (IntMap.insert (Int32.toInt handleId) callback)
   modifyIORef' (asNextId state) (+ 1)
   pure (OnChange handleId)
 
@@ -109,17 +108,11 @@ runActionM state (ActionM f) = f state
 lookupAction :: ActionState -> Int32 -> IO (Maybe (IO ()))
 lookupAction state handleId = do
   callbacks <- readIORef (asCallbacks state)
-  pure (IntMap.lookup (int32ToIntKey handleId) callbacks)
+  pure (IntMap.lookup (Int32.toInt handleId) callbacks)
 
 -- | Look up a text-change callback by handle ID.
 -- Returns 'Nothing' if the ID is not registered.
 lookupTextAction :: ActionState -> Int32 -> IO (Maybe (Text -> IO ()))
 lookupTextAction state handleId = do
   callbacks <- readIORef (asTextCallbacks state)
-  pure (IntMap.lookup (int32ToIntKey handleId) callbacks)
-
--- | Convert Int32 to Int for use as IntMap key.
--- Total on all GHC-supported platforms (Int >= 32 bits).
--- Uses the total chain Int32 -> CInt -> Int.
-int32ToIntKey :: Int32 -> Int
-int32ToIntKey = CInt.toInt . Int32.toCInt
+  pure (IntMap.lookup (Int32.toInt handleId) callbacks)
diff --git a/src/Hatter/Animation.hs b/src/Hatter/Animation.hs
index 592ef0b0..db1085c2 100644
--- a/src/Hatter/Animation.hs
+++ b/src/Hatter/Animation.hs
@@ -31,7 +31,6 @@ import Data.List (sortBy)
 import Data.Ord (comparing)
 import Data.Time.Clock (NominalDiffTime)
 import Foreign.Ptr (Ptr)
-import Unwitch.Convert.CInt qualified as CInt
 import Unwitch.Convert.Int32 qualified as Int32
 import Hatter.Widget
   ( Keyframe(..)
@@ -88,7 +87,7 @@ registerTween animState nodeId keyframes duration = do
         , atNodeId     = nodeId
         , atDuration   = duration
         }
-  modifyIORef' (ansTweens animState) (IntMap.insert (int32ToIntKey nodeId) tween)
+  modifyIORef' (ansTweens animState) (IntMap.insert (Int32.toInt nodeId) tween)
   ensureLoopStarted animState
 
 -- | Start the platform animation loop if not already active.
@@ -257,12 +256,6 @@ interpolateStyle nodeId fromStyle toStyle progress = do
     (Just _fromEnabled, Nothing) -> pure ()
     (Nothing, Nothing) -> pure ()
 
--- | Convert Int32 to Int for use as IntMap key.
--- Total on all GHC-supported platforms (Int >= 32 bits).
--- Uses the total chain Int32 -> CInt -> Int.
-int32ToIntKey :: Int32 -> Int
-int32ToIntKey = CInt.toInt . Int32.toCInt
-
 -- | FFI imports for the C animation bridge.
 foreign import ccall "animation_start_loop" c_animationStartLoop :: Ptr () -> IO ()
 foreign import ccall "animation_stop_loop"  c_animationStopLoop  :: IO ()
diff --git a/src/Hatter/AuthSession.hs b/src/Hatter/AuthSession.hs
index c6f0e853..cc469b0a 100644
--- a/src/Hatter/AuthSession.hs
+++ b/src/Hatter/AuthSession.hs
@@ -90,7 +90,7 @@ authSessionResultFromInt _ _                  _          = Nothing
 startAuthSession :: AuthSessionState -> Text -> Text -> (AuthSessionResult -> IO ()) -> IO ()
 startAuthSession authSessionState authUrl callbackScheme callback = do
   requestId <- readIORef (asNextId authSessionState)
-  modifyIORef' (asCallbacks authSessionState) (IntMap.insert (int32ToIntKey requestId) callback)
+  modifyIORef' (asCallbacks authSessionState) (IntMap.insert (Int32.toInt requestId) callback)
   writeIORef (asNextId authSessionState) (requestId + 1)
   ctx <- readIORef (asContextPtr authSessionState)
   withCString (Text.unpack authUrl) $ \cUrl ->
@@ -115,11 +115,6 @@ dispatchAuthSessionResult authSessionState requestId statusCode maybeRedirectUrl
         Nothing -> hPutStrLn stderr $
           "dispatchAuthSessionResult: unknown request ID " ++ show requestId
 
--- | Convert Int32 to Int for use as IntMap key.
--- Total on all GHC-supported platforms (Int >= 32 bits).
-int32ToIntKey :: Int32 -> Int
-int32ToIntKey = CInt.toInt . Int32.toCInt
-
 -- | FFI import: start an auth session via the C bridge.
 foreign import ccall "auth_session_start"
   c_authSessionStart :: Ptr () -> CInt -> CString -> CString -> IO ()
diff --git a/src/Hatter/BottomSheet.hs b/src/Hatter/BottomSheet.hs
index 9830f107..a901f3f2 100644
--- a/src/Hatter/BottomSheet.hs
+++ b/src/Hatter/BottomSheet.hs
@@ -88,7 +88,7 @@ bottomSheetActionFromInt code
 showBottomSheet :: BottomSheetState -> BottomSheetConfig -> (BottomSheetAction -> IO ()) -> IO ()
 showBottomSheet bottomSheetState config callback = do
   requestId <- readIORef (bssNextId bottomSheetState)
-  modifyIORef' (bssCallbacks bottomSheetState) (IntMap.insert (int32ToIntKey requestId) callback)
+  modifyIORef' (bssCallbacks bottomSheetState) (IntMap.insert (Int32.toInt requestId) callback)
   writeIORef (bssNextId bottomSheetState) (requestId + 1)
   ctx <- readIORef (bssContextPtr bottomSheetState)
   let joinedItems = Text.unpack (Text.intercalate "\n" (bscItems config))
@@ -114,11 +114,6 @@ dispatchBottomSheetResult bottomSheetState requestId actionCode =
         Nothing -> hPutStrLn stderr $
           "dispatchBottomSheetResult: unknown request ID " ++ show requestId
 
--- | Convert Int32 to Int for use as IntMap key.
--- Total on all GHC-supported platforms (Int >= 32 bits).
-int32ToIntKey :: Int32 -> Int
-int32ToIntKey = CInt.toInt . Int32.toCInt
-
 -- | FFI import: show a bottom sheet via the C bridge.
 foreign import ccall "bottom_sheet_show"
   c_bottomSheetShow :: Ptr () -> CInt -> CString -> CString -> IO ()
diff --git a/src/Hatter/Camera.hs b/src/Hatter/Camera.hs
index b7555b0c..28d4c961 100644
--- a/src/Hatter/Camera.hs
+++ b/src/Hatter/Camera.hs
@@ -146,7 +146,7 @@ stopCameraSession _cameraState =
 capturePhoto :: CameraState -> (CameraResult -> IO ()) -> IO ()
 capturePhoto cameraState callback = do
   requestId <- readIORef (csNextId cameraState)
-  modifyIORef' (csCallbacks cameraState) (IntMap.insert (int32ToIntKey requestId) callback)
+  modifyIORef' (csCallbacks cameraState) (IntMap.insert (Int32.toInt requestId) callback)
   writeIORef (csNextId cameraState) (requestId + 1)
   ctx <- readIORef (csContextPtr cameraState)
   c_cameraCapturePhoto ctx (Int32.toCInt requestId)
@@ -165,7 +165,7 @@ startVideoCapture :: CameraState
                   -> IO ()
 startVideoCapture cameraState frameCallback audioCallback completionCallback = do
   requestId <- readIORef (csNextId cameraState)
-  let reqKey = int32ToIntKey requestId
+  let reqKey = Int32.toInt requestId
   modifyIORef' (csCallbacks cameraState) (IntMap.insert reqKey completionCallback)
   modifyIORef' (csFrameCallbacks cameraState) (IntMap.insert reqKey frameCallback)
   modifyIORef' (csAudioCallbacks cameraState) (IntMap.insert reqKey audioCallback)
@@ -246,11 +246,6 @@ dispatchAudioChunk cameraState requestId audioBytes = do
     Nothing -> hPutStrLn stderr $
       "dispatchAudioChunk: unknown request ID " ++ show requestId
 
--- | Convert Int32 to Int for use as IntMap key.
--- Total on all GHC-supported platforms (Int >= 32 bits).
-int32ToIntKey :: Int32 -> Int
-int32ToIntKey = CInt.toInt . Int32.toCInt
-
 -- | FFI import: start a camera session via the C bridge.
 foreign import ccall "camera_start_session"
   c_cameraStartSession :: Ptr () -> CInt -> IO ()
diff --git a/src/Hatter/Dialog.hs b/src/Hatter/Dialog.hs
index 8fc16803..a58ef3f6 100644
--- a/src/Hatter/Dialog.hs
+++ b/src/Hatter/Dialog.hs
@@ -93,7 +93,7 @@ dialogActionFromInt _ = Nothing
 showDialog :: DialogState -> DialogConfig -> (DialogAction -> IO ()) -> IO ()
 showDialog dialogState config callback = do
   requestId <- readIORef (dsNextId dialogState)
-  modifyIORef' (dsCallbacks dialogState) (IntMap.insert (int32ToIntKey requestId) callback)
+  modifyIORef' (dsCallbacks dialogState) (IntMap.insert (Int32.toInt requestId) callback)
   writeIORef (dsNextId dialogState) (requestId + 1)
   ctx <- readIORef (dsContextPtr dialogState)
   withCString (Text.unpack (dcTitle config)) $ \cTitle ->
@@ -126,11 +126,6 @@ withOptionalCString :: Maybe Text -> (CString -> IO a) -> IO a
 withOptionalCString Nothing  action = action nullPtr
 withOptionalCString (Just t) action = withCString (Text.unpack t) action
 
--- | Convert Int32 to Int for use as IntMap key.
--- Total on all GHC-supported platforms (Int >= 32 bits).
-int32ToIntKey :: Int32 -> Int
-int32ToIntKey = CInt.toInt . Int32.toCInt
-
 -- | FFI import: show a dialog via the C bridge.
 foreign import ccall "dialog_show"
   c_dialogShow :: Ptr () -> CInt -> CString -> CString -> CString -> CString -> CString -> IO ()
diff --git a/src/Hatter/Http.hs b/src/Hatter/Http.hs
index b592b867..e420152c 100644
--- a/src/Hatter/Http.hs
+++ b/src/Hatter/Http.hs
@@ -131,7 +131,7 @@ parseHeaders headerText =
 performRequest :: HttpState -> HttpRequest -> (Either HttpError HttpResponse -> IO ()) -> IO ()
 performRequest httpState request callback = do
   requestId <- readIORef (hsNextId httpState)
-  modifyIORef' (hsCallbacks httpState) (IntMap.insert (int32ToIntKey requestId) callback)
+  modifyIORef' (hsCallbacks httpState) (IntMap.insert (Int32.toInt requestId) callback)
   writeIORef (hsNextId httpState) (requestId + 1)
   ctx <- readIORef (hsContextPtr httpState)
   let methodInt = httpMethodToInt (hrMethod request)
@@ -165,11 +165,6 @@ dispatchHttpResult httpState requestId resultCode httpStatus maybeHeaders respon
     Nothing -> hPutStrLn stderr $
       "dispatchHttpResult: unknown request ID " ++ show requestId
 
--- | Convert Int32 to Int for use as IntMap key.
--- Total on all GHC-supported platforms (Int >= 32 bits).
-int32ToIntKey :: Int32 -> Int
-int32ToIntKey = CInt.toInt . Int32.toCInt
-
 -- | FFI import: send an HTTP request via the C bridge.
 foreign import ccall "http_request"
   c_httpRequest :: Ptr () -> CInt -> CInt -> CString -> CString
diff --git a/src/Hatter/Permission.hs b/src/Hatter/Permission.hs
index e6112493..dc18aa3e 100644
--- a/src/Hatter/Permission.hs
+++ b/src/Hatter/Permission.hs
@@ -100,7 +100,7 @@ permissionStatusFromInt _ = Nothing
 requestPermission :: PermissionState -> Permission -> (PermissionStatus -> IO ()) -> IO ()
 requestPermission permissionState permission callback = do
   requestId <- readIORef (psNextId permissionState)
-  modifyIORef' (psCallbacks permissionState) (IntMap.insert (int32ToIntKey requestId) callback)
+  modifyIORef' (psCallbacks permissionState) (IntMap.insert (Int32.toInt requestId) callback)
   writeIORef (psNextId permissionState) (requestId + 1)
   ctx <- readIORef (psContextPtr permissionState)
   c_permissionRequest ctx (permissionToInt permission) (Int32.toCInt requestId)
@@ -132,11 +132,6 @@ dispatchPermissionResult permissionState requestId statusCode =
           modifyIORef' (psCallbacks permissionState) (IntMap.delete (CInt.toInt requestId))
           callback status
 
--- | Convert Int32 to Int for use as IntMap key.
--- Total on all GHC-supported platforms (Int >= 32 bits).
-int32ToIntKey :: Int32 -> Int
-int32ToIntKey = CInt.toInt . Int32.toCInt
-
 -- | FFI import: request a permission via the C bridge.
 -- Takes an opaque context pointer, permission code, and request ID.
 foreign import ccall "permission_request"
diff --git a/src/Hatter/PlatformSignIn.hs b/src/Hatter/PlatformSignIn.hs
index ef23a2f1..fa987b8f 100644
--- a/src/Hatter/PlatformSignIn.hs
+++ b/src/Hatter/PlatformSignIn.hs
@@ -128,7 +128,7 @@ signInResultFromInt _ _ _ _ _ _ = Nothing
 startPlatformSignIn :: PlatformSignInState -> SignInProvider -> (SignInResult -> IO ()) -> IO ()
 startPlatformSignIn signInState provider callback = do
   requestId <- readIORef (psiNextId signInState)
-  modifyIORef' (psiCallbacks signInState) (IntMap.insert (int32ToIntKey requestId) callback)
+  modifyIORef' (psiCallbacks signInState) (IntMap.insert (Int32.toInt requestId) callback)
   writeIORef (psiNextId signInState) (requestId + 1)
   ctx <- readIORef (psiContextPtr signInState)
   c_platformSignInStart ctx (Int32.toCInt requestId) (providerToInt provider)
@@ -151,11 +151,6 @@ dispatchPlatformSignInResult signInState requestId statusCode maybeToken maybeUs
         Nothing -> hPutStrLn stderr $
           "dispatchPlatformSignInResult: unknown request ID " ++ show requestId
 
--- | Convert Int32 to Int for use as IntMap key.
--- Total on all GHC-supported platforms (Int >= 32 bits).
-int32ToIntKey :: Int32 -> Int
-int32ToIntKey = CInt.toInt . Int32.toCInt
-
 -- | FFI import: start a platform sign-in via the C bridge.
 foreign import ccall "platform_sign_in_start"
   c_platformSignInStart :: Ptr () -> CInt -> CInt -> IO ()
diff --git a/src/Hatter/SecureStorage.hs b/src/Hatter/SecureStorage.hs
index 4998ba68..33b218d1 100644
--- a/src/Hatter/SecureStorage.hs
+++ b/src/Hatter/SecureStorage.hs
@@ -91,7 +91,7 @@ storageStatusFromInt _ = Nothing
 secureStorageWrite :: SecureStorageState -> Text -> Text -> (SecureStorageStatus -> IO ()) -> IO ()
 secureStorageWrite storageState key value callback = do
   requestId <- readIORef (ssNextId storageState)
-  modifyIORef' (ssWriteCallbacks storageState) (IntMap.insert (int32ToIntKey requestId) callback)
+  modifyIORef' (ssWriteCallbacks storageState) (IntMap.insert (Int32.toInt requestId) callback)
   writeIORef (ssNextId storageState) (requestId + 1)
   ctx <- readIORef (ssContextPtr storageState)
   withCString (Text.unpack key) $ \cKey ->
@@ -104,7 +104,7 @@ secureStorageWrite storageState key value callback = do
 secureStorageRead :: SecureStorageState -> Text -> (SecureStorageStatus -> Maybe Text -> IO ()) -> IO ()
 secureStorageRead storageState key callback = do
   requestId <- readIORef (ssNextId storageState)
-  modifyIORef' (ssReadCallbacks storageState) (IntMap.insert (int32ToIntKey requestId) callback)
+  modifyIORef' (ssReadCallbacks storageState) (IntMap.insert (Int32.toInt requestId) callback)
   writeIORef (ssNextId storageState) (requestId + 1)
   ctx <- readIORef (ssContextPtr storageState)
   withCString (Text.unpack key) $ \cKey ->
@@ -115,7 +115,7 @@ secureStorageRead storageState key callback = do
 secureStorageDelete :: SecureStorageState -> Text -> (SecureStorageStatus -> IO ()) -> IO ()
 secureStorageDelete storageState key callback = do
   requestId <- readIORef (ssNextId storageState)
-  modifyIORef' (ssDeleteCallbacks storageState) (IntMap.insert (int32ToIntKey requestId) callback)
+  modifyIORef' (ssDeleteCallbacks storageState) (IntMap.insert (Int32.toInt requestId) callback)
   writeIORef (ssNextId storageState) (requestId + 1)
   ctx <- readIORef (ssContextPtr storageState)
   withCString (Text.unpack key) $ \cKey ->
@@ -158,11 +158,6 @@ dispatchSecureStorageResult storageState requestId statusCode maybeValue =
                 Nothing -> hPutStrLn stderr $
                   "dispatchSecureStorageResult: unknown request ID " ++ show requestId
 
--- | Convert Int32 to Int for use as IntMap key.
--- Total on all GHC-supported platforms (Int >= 32 bits).
-int32ToIntKey :: Int32 -> Int
-int32ToIntKey = CInt.toInt . Int32.toCInt
-
 -- | FFI import: write a key-value pair via the C bridge.
 foreign import ccall "secure_storage_write"
   c_secureStorageWrite :: Ptr () -> CInt -> CString -> CString -> IO ()