diff --git a/lsp-types/lsp-types.cabal b/lsp-types/lsp-types.cabal
index 4ca08008a..02b795423 100644
--- a/lsp-types/lsp-types.cabal
+++ b/lsp-types/lsp-types.cabal
@@ -86,6 +86,7 @@ library
                      , lens >= 4.15.2
                      , mtl
                      , network-uri
+                     , mod
                      , rope-utf16-splay >= 0.3.1.0
                      , scientific
                      , some
diff --git a/lsp-types/src/Language/LSP/Types/Common.hs b/lsp-types/src/Language/LSP/Types/Common.hs
index e36ad62e0..fdc1ad04d 100644
--- a/lsp-types/src/Language/LSP/Types/Common.hs
+++ b/lsp-types/src/Language/LSP/Types/Common.hs
@@ -1,6 +1,9 @@
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE DataKinds                  #-}
+{-# LANGUAGE DeriveAnyClass             #-}
 {-# LANGUAGE DeriveTraversable          #-}
 {-# LANGUAGE DeriveGeneric              #-}
+{-# LANGUAGE DerivingStrategies         #-}
 {-# LANGUAGE TypeOperators              #-}
 
 -- | Common types that aren't in the specification
@@ -10,14 +13,44 @@ module Language.LSP.Types.Common (
   , List (..)
   , Empty (..)
   , Int32
-  , Word32 ) where
+  , UInt ) where
 
 import Control.Applicative
 import Control.DeepSeq
 import Data.Aeson
 import Data.Int (Int32)
-import Data.Word (Word32)
-import GHC.Generics
+import Data.Mod.Word
+import Text.Read (Read(readPrec))
+import GHC.Generics hiding (UInt)
+import GHC.TypeNats hiding (Mod)
+import Data.Bifunctor (bimap)
+
+-- | The "uinteger" type in the LSP spec.
+--
+-- Unusually, this is a **31**-bit unsigned integer, not a 32-bit one.
+newtype UInt = UInt (Mod (2^31))
+  deriving newtype (Num, Bounded, Enum, Eq, Ord)
+  deriving stock (Generic)
+  deriving anyclass (NFData)
+
+instance Show UInt where
+  show (UInt u) = show $ unMod u
+
+instance Read UInt where
+  readPrec = fromInteger <$> readPrec
+
+instance Real UInt where
+  toRational (UInt u) = toRational $ unMod u
+
+instance Integral UInt where
+  quotRem (UInt x) (UInt y) = bimap fromIntegral fromIntegral $ quotRem (unMod x) (unMod y)
+  toInteger (UInt u) = toInteger $ unMod u
+
+instance ToJSON UInt where
+  toJSON u = toJSON (toInteger u)
+
+instance FromJSON UInt where
+  parseJSON v = fromInteger <$> parseJSON v
 
 -- | A terser, isomorphic data type for 'Either', that does not get tagged when
 -- converting to and from JSON.
@@ -46,7 +79,8 @@ instance (NFData a, NFData b) => NFData (a |? b)
 -- In particular this is necessary to change the 'FromJSON' instance to be compatible
 -- with Elisp (where empty lists show up as 'null')
 newtype List a = List [a]
-                deriving (Show,Read,Eq,Ord,Semigroup,Monoid,Functor,Foldable,Traversable,Generic)
+    deriving stock (Traversable,Generic)
+    deriving newtype (Show,Read,Eq,Ord,Semigroup,Monoid,Functor,Foldable)
 
 instance NFData a => NFData (List a)
 
diff --git a/lsp-types/src/Language/LSP/Types/Diagnostic.hs b/lsp-types/src/Language/LSP/Types/Diagnostic.hs
index 35a94fe62..4d17b1ba9 100644
--- a/lsp-types/src/Language/LSP/Types/Diagnostic.hs
+++ b/lsp-types/src/Language/LSP/Types/Diagnostic.hs
@@ -9,7 +9,7 @@ import           Control.DeepSeq
 import qualified Data.Aeson                                 as A
 import           Data.Aeson.TH
 import           Data.Text
-import           GHC.Generics
+import           GHC.Generics hiding (UInt)
 import           Language.LSP.Types.Common
 import           Language.LSP.Types.Location
 import           Language.LSP.Types.Uri
@@ -131,7 +131,7 @@ data PublishDiagnosticsParams =
       -- published for.
       -- 
       -- Since LSP 3.15.0
-    , _version     :: Maybe Word32
+    , _version     :: Maybe UInt
       -- | An array of diagnostic information items.
     , _diagnostics :: List Diagnostic
     } deriving (Read,Show,Eq)
diff --git a/lsp-types/src/Language/LSP/Types/FoldingRange.hs b/lsp-types/src/Language/LSP/Types/FoldingRange.hs
index 07cfdc998..c89a4d010 100644
--- a/lsp-types/src/Language/LSP/Types/FoldingRange.hs
+++ b/lsp-types/src/Language/LSP/Types/FoldingRange.hs
@@ -24,7 +24,7 @@ data FoldingRangeClientCapabilities =
       _dynamicRegistration :: Maybe Bool
       -- | The maximum number of folding ranges that the client prefers to receive
       -- per document. The value serves as a hint, servers are free to follow the limit.
-    , _rangeLimit          :: Maybe Word32
+    , _rangeLimit          :: Maybe UInt
       -- | If set, the client signals that it only supports folding complete lines. If set,
       -- client will ignore specified `startCharacter` and `endCharacter` properties in a
       -- FoldingRange.
@@ -80,15 +80,15 @@ instance A.FromJSON FoldingRangeKind where
 data FoldingRange =
   FoldingRange
   { -- | The zero-based line number from where the folded range starts.
-    _startLine      :: Word32
+    _startLine      :: UInt
     -- | The zero-based character offset from where the folded range
     -- starts. If not defined, defaults to the length of the start line.
-  , _startCharacter :: Maybe Word32
+  , _startCharacter :: Maybe UInt
     -- | The zero-based line number where the folded range ends.
-  , _endLine        :: Word32
+  , _endLine        :: UInt
     -- | The zero-based character offset before the folded range ends.
     -- If not defined, defaults to the length of the end line.
-  , _endCharacter   :: Maybe Word32
+  , _endCharacter   :: Maybe UInt
     -- | Describes the kind of the folding range such as 'comment' or
     -- 'region'. The kind is used to categorize folding ranges and used
     -- by commands like 'Fold all comments'. See 'FoldingRangeKind' for
diff --git a/lsp-types/src/Language/LSP/Types/Formatting.hs b/lsp-types/src/Language/LSP/Types/Formatting.hs
index 6ca95069c..8bed6e734 100644
--- a/lsp-types/src/Language/LSP/Types/Formatting.hs
+++ b/lsp-types/src/Language/LSP/Types/Formatting.hs
@@ -30,7 +30,7 @@ deriveJSON lspOptions ''DocumentFormattingRegistrationOptions
 -- | Value-object describing what options formatting should use.
 data FormattingOptions = FormattingOptions
   { -- | Size of a tab in spaces.
-    _tabSize :: Word32,
+    _tabSize :: UInt,
     -- | Prefer spaces over tabs
     _insertSpaces :: Bool,
     -- | Trim trailing whitespace on a line.
diff --git a/lsp-types/src/Language/LSP/Types/Location.hs b/lsp-types/src/Language/LSP/Types/Location.hs
index a05cb698e..0b463821d 100644
--- a/lsp-types/src/Language/LSP/Types/Location.hs
+++ b/lsp-types/src/Language/LSP/Types/Location.hs
@@ -14,11 +14,11 @@ import           Language.LSP.Types.Utils
 data Position =
   Position
     { -- | Line position in a document (zero-based).
-      _line      :: Word32
+      _line      :: UInt
       -- | Character offset on a line in a document (zero-based). Assuming that
       -- the line is represented as a string, the @character@ value represents the
       -- gap between the @character@ and @character + 1@.
-    , _character :: Word32
+    , _character :: UInt
     } deriving (Show, Read, Eq, Ord, Generic)
 
 instance NFData Position
@@ -73,5 +73,5 @@ deriveJSON lspOptions ''LocationLink
 
 -- | A helper function for creating ranges.
 -- prop> mkRange l c l' c' = Range (Position l c) (Position l' c')
-mkRange :: Word32 -> Word32 -> Word32 -> Word32 -> Range
+mkRange :: UInt -> UInt -> UInt -> UInt -> Range
 mkRange l c l' c' = Range (Position l c) (Position l' c')
diff --git a/lsp-types/src/Language/LSP/Types/Progress.hs b/lsp-types/src/Language/LSP/Types/Progress.hs
index cf9f8ffbd..e9929de31 100644
--- a/lsp-types/src/Language/LSP/Types/Progress.hs
+++ b/lsp-types/src/Language/LSP/Types/Progress.hs
@@ -59,7 +59,7 @@ data WorkDoneProgressBeginParams =
   --
   -- The value should be steadily rising. Clients are free to ignore values
   -- that are not following this rule.
-  , _percentage :: Maybe Word32
+  , _percentage :: Maybe UInt
   } deriving (Show, Read, Eq)
 
 instance A.ToJSON WorkDoneProgressBeginParams where
@@ -104,7 +104,7 @@ data WorkDoneProgressReportParams =
   -- If infinite progress was indicated in the start notification client
   -- are allowed to ignore the value. In addition the value should be steadily
   -- rising. Clients are free to ignore values that are not following this rule.
-  , _percentage :: Maybe Word32
+  , _percentage :: Maybe UInt
   } deriving (Show, Read, Eq)
 
 instance A.ToJSON WorkDoneProgressReportParams where
diff --git a/lsp-types/src/Language/LSP/Types/SemanticTokens.hs b/lsp-types/src/Language/LSP/Types/SemanticTokens.hs
index 283063686..ca554bfbc 100644
--- a/lsp-types/src/Language/LSP/Types/SemanticTokens.hs
+++ b/lsp-types/src/Language/LSP/Types/SemanticTokens.hs
@@ -292,12 +292,12 @@ data SemanticTokens = SemanticTokens {
   _resultId :: Maybe Text,
 
   -- | The actual tokens.
-  _xdata    :: List Word32
+  _xdata    :: List UInt
 } deriving (Show, Read, Eq)
 deriveJSON lspOptions ''SemanticTokens
 
 data SemanticTokensPartialResult = SemanticTokensPartialResult {
-  _xdata :: List Word32
+  _xdata :: List UInt
 }
 deriveJSON lspOptions ''SemanticTokensPartialResult
 
@@ -311,11 +311,11 @@ deriveJSON lspOptions ''SemanticTokensDeltaParams
 
 data SemanticTokensEdit = SemanticTokensEdit {
   -- | The start offset of the edit.
-  _start       :: Word32,
+  _start       :: UInt,
   -- | The count of elements to remove.
-  _deleteCount :: Word32,
+  _deleteCount :: UInt,
   -- | The elements to insert.
-  _xdata       :: Maybe (List Word32)
+  _xdata       :: Maybe (List UInt)
 } deriving (Show, Read, Eq)
 deriveJSON lspOptions ''SemanticTokensEdit
 
@@ -359,9 +359,9 @@ deriveJSON lspOptions ''SemanticTokensWorkspaceClientCapabilities
 -- | A single 'semantic token' as described in the LSP specification, using absolute positions.
 -- This is the kind of token that is usually easiest for editors to produce.
 data SemanticTokenAbsolute = SemanticTokenAbsolute {
-  line           :: Word32,
-  startChar      :: Word32,
-  length         :: Word32,
+  line           :: UInt,
+  startChar      :: UInt,
+  length         :: UInt,
   tokenType      :: SemanticTokenTypes,
   tokenModifiers :: [SemanticTokenModifiers]
 } deriving (Show, Read, Eq, Ord)
@@ -370,9 +370,9 @@ data SemanticTokenAbsolute = SemanticTokenAbsolute {
 
 -- | A single 'semantic token' as described in the LSP specification, using relative positions.
 data SemanticTokenRelative = SemanticTokenRelative {
-  deltaLine      :: Word32,
-  deltaStartChar :: Word32,
-  length         :: Word32,
+  deltaLine      :: UInt,
+  deltaStartChar :: UInt,
+  length         :: UInt,
   tokenType      :: SemanticTokenTypes,
   tokenModifiers :: [SemanticTokenModifiers]
 } deriving (Show, Read, Eq, Ord)
@@ -385,7 +385,7 @@ relativizeTokens :: [SemanticTokenAbsolute] -> [SemanticTokenRelative]
 relativizeTokens xs = DList.toList $ go 0 0 xs mempty
   where
     -- Pass an accumulator to make this tail-recursive
-    go :: Word32 -> Word32 -> [SemanticTokenAbsolute] -> DList.DList SemanticTokenRelative -> DList.DList SemanticTokenRelative
+    go :: UInt -> UInt -> [SemanticTokenAbsolute] -> DList.DList SemanticTokenRelative -> DList.DList SemanticTokenRelative
     go _ _ [] acc = acc
     go lastLine lastChar (SemanticTokenAbsolute l c len ty mods:ts) acc =
       let
@@ -400,7 +400,7 @@ absolutizeTokens :: [SemanticTokenRelative] -> [SemanticTokenAbsolute]
 absolutizeTokens xs = DList.toList $ go 0 0 xs mempty
   where
     -- Pass an accumulator to make this tail-recursive
-    go :: Word32 -> Word32 -> [SemanticTokenRelative] -> DList.DList SemanticTokenAbsolute -> DList.DList SemanticTokenAbsolute
+    go :: UInt -> UInt -> [SemanticTokenRelative] -> DList.DList SemanticTokenAbsolute -> DList.DList SemanticTokenAbsolute
     go _ _ [] acc = acc
     go lastLine lastChar (SemanticTokenRelative dl dc len ty mods:ts) acc =
       let
@@ -410,18 +410,18 @@ absolutizeTokens xs = DList.toList $ go 0 0 xs mempty
       in go l c ts (DList.snoc acc (SemanticTokenAbsolute l c len ty mods))
 
 -- | Encode a series of relatively-positioned semantic tokens into an integer array following the given legend.
-encodeTokens :: SemanticTokensLegend -> [SemanticTokenRelative] -> Either Text [Word32]
+encodeTokens :: SemanticTokensLegend -> [SemanticTokenRelative] -> Either Text [UInt]
 encodeTokens SemanticTokensLegend{_tokenTypes=List tts,_tokenModifiers=List tms} sts =
   DList.toList . DList.concat <$> traverse encodeToken sts
   where
     -- Note that there's no "fast" version of these (e.g. backed by an IntMap or similar)
     -- in general, due to the possibility  of unknown token types which are only identified by strings.
-    tyMap :: Map.Map SemanticTokenTypes Word32
+    tyMap :: Map.Map SemanticTokenTypes UInt
     tyMap = Map.fromList $ zip tts [0..]
     modMap :: Map.Map SemanticTokenModifiers Int
     modMap = Map.fromList $ zip tms [0..]
 
-    lookupTy :: SemanticTokenTypes -> Either Text Word32
+    lookupTy :: SemanticTokenTypes -> Either Text UInt
     lookupTy ty = case Map.lookup ty tyMap of
         Just tycode -> pure tycode
         Nothing -> throwError $ "Semantic token type " <> fromString (show ty) <> " did not appear in the legend"
@@ -431,17 +431,17 @@ encodeTokens SemanticTokensLegend{_tokenTypes=List tts,_tokenModifiers=List tms}
         Nothing -> throwError $ "Semantic token modifier " <> fromString (show modifier) <> " did not appear in the legend"
 
     -- Use a DList here for better efficiency when concatenating all these together
-    encodeToken :: SemanticTokenRelative -> Either Text (DList.DList Word32)
+    encodeToken :: SemanticTokenRelative -> Either Text (DList.DList UInt)
     encodeToken (SemanticTokenRelative dl dc len ty mods) = do
       tycode <- lookupTy ty
       modcodes <- traverse lookupMod mods
-      let combinedModcode :: Word32 = foldl' Bits.setBit Bits.zeroBits modcodes
+      let combinedModcode :: Int = foldl' Bits.setBit Bits.zeroBits modcodes
 
-      pure [dl, dc, len, tycode, combinedModcode ]
+      pure [dl, dc, len, tycode, fromIntegral combinedModcode ]
 
 -- This is basically 'SemanticTokensEdit', but slightly easier to work with.
 -- | An edit to a buffer of items. 
-data Edit a = Edit { editStart :: Word32, editDeleteCount :: Word32, editInsertions :: [a] }
+data Edit a = Edit { editStart :: UInt, editDeleteCount :: UInt, editInsertions :: [a] }
   deriving (Read, Show, Eq, Ord)
 
 -- | Compute a list of edits that will turn the first list into the second list.
@@ -455,7 +455,7 @@ computeEdits l r = DList.toList $ go 0 Nothing (Diff.getGroupedDiff l r) mempty
     dump the 'Edit' into the accumulator.
     We need the index, because 'Edit's need to say where they start.
     -}
-    go :: Word32 -> Maybe (Edit a) -> [Diff.Diff [a]] -> DList.DList (Edit a) -> DList.DList (Edit a)
+    go :: UInt -> Maybe (Edit a) -> [Diff.Diff [a]] -> DList.DList (Edit a) -> DList.DList (Edit a)
     -- No more diffs: append the current edit if there is one and return
     go _ e [] acc = acc <> DList.fromList (maybeToList e)
 
diff --git a/lsp-types/src/Language/LSP/Types/SignatureHelp.hs b/lsp-types/src/Language/LSP/Types/SignatureHelp.hs
index e2ca51f2a..4d7955957 100644
--- a/lsp-types/src/Language/LSP/Types/SignatureHelp.hs
+++ b/lsp-types/src/Language/LSP/Types/SignatureHelp.hs
@@ -85,7 +85,7 @@ deriveJSON lspOptionsUntagged ''SignatureHelpDoc
 
 -- -------------------------------------
 
-data ParameterLabel = ParameterLabelString Text | ParameterLabelOffset Word32 Word32
+data ParameterLabel = ParameterLabelString Text | ParameterLabelOffset UInt UInt
   deriving (Read,Show,Eq)
 
 instance ToJSON ParameterLabel where
@@ -127,7 +127,7 @@ data SignatureInformation =
     { _label           :: Text -- ^ The label of the signature.
     , _documentation   :: Maybe SignatureHelpDoc -- ^ The human-readable doc-comment of this signature.
     , _parameters      :: Maybe (List ParameterInformation) -- ^ The parameters of this signature.
-    , _activeParameter :: Maybe Word32 -- ^ The index of the active parameter.
+    , _activeParameter :: Maybe UInt -- ^ The index of the active parameter.
     } deriving (Read,Show,Eq)
 
 deriveJSON lspOptions ''SignatureInformation
@@ -141,8 +141,8 @@ active and only one active parameter.
 data SignatureHelp =
   SignatureHelp
     { _signatures      :: List SignatureInformation -- ^ One or more signatures.
-    , _activeSignature :: Maybe Word32 -- ^ The active signature.
-    , _activeParameter :: Maybe Word32 -- ^ The active parameter of the active signature.
+    , _activeSignature :: Maybe UInt -- ^ The active signature.
+    , _activeParameter :: Maybe UInt -- ^ The active parameter of the active signature.
     } deriving (Read,Show,Eq)
 
 deriveJSON lspOptions ''SignatureHelp
diff --git a/lsp-types/src/Language/LSP/Types/TextDocument.hs b/lsp-types/src/Language/LSP/Types/TextDocument.hs
index 8f6cf03e8..69bbe0470 100644
--- a/lsp-types/src/Language/LSP/Types/TextDocument.hs
+++ b/lsp-types/src/Language/LSP/Types/TextDocument.hs
@@ -169,7 +169,7 @@ data TextDocumentContentChangeEvent =
       _range       :: Maybe Range
       -- | The optional length of the range that got replaced.
       -- Deprecated, use _range instead
-    , _rangeLength :: Maybe Word32
+    , _rangeLength :: Maybe UInt
       -- | The new text for the provided range, if provided.
       -- Otherwise the new text of the whole document.
     , _text        :: Text
diff --git a/lsp-types/src/Language/LSP/Types/WorkspaceEdit.hs b/lsp-types/src/Language/LSP/Types/WorkspaceEdit.hs
index f30f658ea..ecd01ad9b 100644
--- a/lsp-types/src/Language/LSP/Types/WorkspaceEdit.hs
+++ b/lsp-types/src/Language/LSP/Types/WorkspaceEdit.hs
@@ -363,7 +363,7 @@ data ApplyWorkspaceEditResponseBody =
       -- might contain the index of the change that failed. This property is
       -- only available if the client signals a `failureHandling` strategy
       -- in its client capabilities.
-    , _failedChange :: Maybe Word32
+    , _failedChange :: Maybe UInt
     } deriving (Show, Read, Eq)
 
 deriveJSON lspOptions ''ApplyWorkspaceEditResponseBody
@@ -388,7 +388,7 @@ applyTextEdit (TextEdit (Range sp ep) newText) oldText =
         in T.splitAt (fromIntegral index) t
 
     -- The index of the first character of line 'line'
-    startLineIndex :: Word32 -> Text -> Word32
+    startLineIndex :: UInt -> Text -> UInt
     startLineIndex 0 _ = 0
     startLineIndex line t' =
       case T.findIndex (== '\n') t' of
diff --git a/lsp/example/Reactor.hs b/lsp/example/Reactor.hs
index 81a69d2a1..20724d87e 100644
--- a/lsp/example/Reactor.hs
+++ b/lsp/example/Reactor.hs
@@ -280,7 +280,7 @@ handle = mconcat
       responder (Right (J.Object mempty)) -- respond to the request
 
       void $ withProgress "Executing some long running command" Cancellable $ \update ->
-        forM [(0 :: J.Word32)..10] $ \i -> do
+        forM [(0 :: J.UInt)..10] $ \i -> do
           update (ProgressAmount (Just (i * 10)) (Just "Doing stuff"))
           liftIO $ threadDelay (1 * 1000000)
   ]
diff --git a/lsp/src/Language/LSP/Server/Core.hs b/lsp/src/Language/LSP/Server/Core.hs
index 8baac748a..267b978e3 100644
--- a/lsp/src/Language/LSP/Server/Core.hs
+++ b/lsp/src/Language/LSP/Server/Core.hs
@@ -267,7 +267,7 @@ defaultOptions = def
 -- an optional message to go with it during a 'withProgress'
 --
 -- @since 0.10.0.0
-data ProgressAmount = ProgressAmount (Maybe Word32) (Maybe Text)
+data ProgressAmount = ProgressAmount (Maybe UInt) (Maybe Text)
 
 -- | Thrown if the user cancels a 'Cancellable' 'withProgress'/'withIndefiniteProgress'/ session
 --
diff --git a/lsp/test/JsonSpec.hs b/lsp/test/JsonSpec.hs
index c7b2194cd..7d77e9402 100644
--- a/lsp/test/JsonSpec.hs
+++ b/lsp/test/JsonSpec.hs
@@ -99,6 +99,9 @@ instance Arbitrary HoverContents where
                     , HoverContents <$> arbitrary
                     ]
 
+instance Arbitrary UInt where
+  arbitrary = fromInteger <$> arbitrary
+
 instance Arbitrary Uri where
   arbitrary = Uri <$> arbitrary
 
diff --git a/lsp/test/SemanticTokensSpec.hs b/lsp/test/SemanticTokensSpec.hs
index dab8943a5..89feeb36d 100644
--- a/lsp/test/SemanticTokensSpec.hs
+++ b/lsp/test/SemanticTokensSpec.hs
@@ -21,7 +21,7 @@ spec = do
         , SemanticTokenAbsolute 6 2 7 SttClass []
         ]
 
-      bigNumber :: Word32
+      bigNumber :: UInt
       bigNumber = 100000
       bigTokens =
         unfoldr (\i -> if i == bigNumber then Nothing else Just (SemanticTokenAbsolute i 1 1 SttType [StmUnknown "private", StmStatic], i+1)) 0
@@ -31,12 +31,12 @@ spec = do
 
       -- One more order of magnitude makes diffing more-or-less hang - possibly we need a better diffing algorithm, since this is only ~= 200 tokens at 5 ints per token
       -- (I checked and it is the diffing that's slow, not turning it into edits)
-      smallerBigNumber :: Word32
+      smallerBigNumber :: UInt
       smallerBigNumber = 1000
-      bigInts :: [Word32]
+      bigInts :: [UInt]
       bigInts =
         unfoldr (\i -> if i == smallerBigNumber then Nothing else Just (1, i+1)) 0
-      bigInts2 :: [Word32]
+      bigInts2 :: [UInt]
       bigInts2 =
         unfoldr (\i -> if i == smallerBigNumber then Nothing else Just (if even i then 2 else 1, i+1)) 0
 
@@ -71,4 +71,4 @@ spec = do
       computeEdits @Int [1,2,3,4,5] [1,6,3,7,7,5] `shouldBe` [Edit 1 1 [6], Edit 3 1 [7,7]]
     it "handles big tokens" $
       -- It's a little hard to specify a useful predicate here, the main point is that it should not take too long
-      computeEdits @Word32 bigInts bigInts2 `shouldSatisfy` (not . null)
+      computeEdits @UInt bigInts bigInts2 `shouldSatisfy` (not . null)
diff --git a/lsp/test/VspSpec.hs b/lsp/test/VspSpec.hs
index e970f7454..2909995f9 100644
--- a/lsp/test/VspSpec.hs
+++ b/lsp/test/VspSpec.hs
@@ -26,10 +26,6 @@ spec = describe "VSP functions" vspSpec
 
 -- ---------------------------------------------------------------------
 
-
-mkRange :: J.Word32 -> J.Word32 -> J.Word32 -> J.Word32 -> Maybe J.Range
-mkRange ls cs le ce = Just $ J.Range (J.Position ls cs) (J.Position le ce)
-
 vfsFromText :: T.Text -> VirtualFile
 vfsFromText text = VirtualFile 0 0 (Rope.fromText text)
 
@@ -41,17 +37,17 @@ vspSpec = do
     it "handles vscode style undos" $ do
       let orig = "abc"
           changes =
-            [ J.TextDocumentContentChangeEvent (mkRange 0 2 0 3) Nothing ""
-            , J.TextDocumentContentChangeEvent (mkRange 0 1 0 2) Nothing ""
-            , J.TextDocumentContentChangeEvent (mkRange 0 0 0 1) Nothing ""
+            [ J.TextDocumentContentChangeEvent (Just $ J.mkRange 0 2 0 3) Nothing ""
+            , J.TextDocumentContentChangeEvent (Just $ J.mkRange 0 1 0 2) Nothing ""
+            , J.TextDocumentContentChangeEvent (Just $ J.mkRange 0 0 0 1) Nothing ""
             ]
       applyChanges orig changes `shouldBe` ""
     it "handles vscode style redos" $ do
       let orig = ""
           changes =
-            [ J.TextDocumentContentChangeEvent (mkRange 0 1 0 1) Nothing "a"
-            , J.TextDocumentContentChangeEvent (mkRange 0 2 0 2) Nothing "b"
-            , J.TextDocumentContentChangeEvent (mkRange 0 3 0 3) Nothing "c"
+            [ J.TextDocumentContentChangeEvent (Just $ J.mkRange 0 1 0 1) Nothing "a"
+            , J.TextDocumentContentChangeEvent (Just $ J.mkRange 0 2 0 2) Nothing "b"
+            , J.TextDocumentContentChangeEvent (Just $ J.mkRange 0 3 0 3) Nothing "c"
             ]
       applyChanges orig changes `shouldBe` "abc"
 
@@ -68,7 +64,7 @@ vspSpec = do
           , "foo :: Int"
           ]
         new = applyChange (fromString orig)
-                $ J.TextDocumentContentChangeEvent (mkRange 2 1 2 5) (Just 4) ""
+                $ J.TextDocumentContentChangeEvent (Just $ J.mkRange 2 1 2 5) (Just 4) ""
       lines (Rope.toString new) `shouldBe`
           [ "abcdg"
           , "module Foo where"
@@ -85,7 +81,7 @@ vspSpec = do
           , "foo :: Int"
           ]
         new = applyChange (fromString orig)
-                $ J.TextDocumentContentChangeEvent (mkRange 2 1 2 5) Nothing ""
+                $ J.TextDocumentContentChangeEvent (Just $ J.mkRange 2 1 2 5) Nothing ""
       lines (Rope.toString new) `shouldBe`
           [ "abcdg"
           , "module Foo where"
@@ -105,7 +101,7 @@ vspSpec = do
           , "foo :: Int"
           ]
         new = applyChange (fromString orig)
-                $ J.TextDocumentContentChangeEvent (mkRange 2 0 3 0) (Just 8) ""
+                $ J.TextDocumentContentChangeEvent (Just $ J.mkRange 2 0 3 0) (Just 8) ""
       lines (Rope.toString new) `shouldBe`
           [ "abcdg"
           , "module Foo where"
@@ -122,7 +118,7 @@ vspSpec = do
           , "foo :: Int"
           ]
         new = applyChange (fromString orig)
-                $ J.TextDocumentContentChangeEvent (mkRange 2 0 3 0) Nothing ""
+                $ J.TextDocumentContentChangeEvent (Just $ J.mkRange 2 0 3 0) Nothing ""
       lines (Rope.toString new) `shouldBe`
           [ "abcdg"
           , "module Foo where"
@@ -140,7 +136,7 @@ vspSpec = do
           , "foo = bb"
           ]
         new = applyChange (fromString orig)
-                $ J.TextDocumentContentChangeEvent (mkRange 1 0 3 0) (Just 19) ""
+                $ J.TextDocumentContentChangeEvent (Just $ J.mkRange 1 0 3 0) (Just 19) ""
       lines (Rope.toString new) `shouldBe`
           [ "module Foo where"
           , "foo = bb"
@@ -156,7 +152,7 @@ vspSpec = do
           , "foo = bb"
           ]
         new = applyChange (fromString orig)
-                $ J.TextDocumentContentChangeEvent (mkRange 1 0 3 0) Nothing ""
+                $ J.TextDocumentContentChangeEvent (Just $ J.mkRange 1 0 3 0) Nothing ""
       lines (Rope.toString new) `shouldBe`
           [ "module Foo where"
           , "foo = bb"
@@ -173,7 +169,7 @@ vspSpec = do
           , "foo :: Int"
           ]
         new = applyChange (fromString orig)
-                $ J.TextDocumentContentChangeEvent (mkRange 1 16 1 16) (Just 0) "\n-- fooo"
+                $ J.TextDocumentContentChangeEvent (Just $ J.mkRange 1 16 1 16) (Just 0) "\n-- fooo"
       lines (Rope.toString new) `shouldBe`
           [ "abcdg"
           , "module Foo where"
@@ -191,7 +187,7 @@ vspSpec = do
           , "foo = bb"
           ]
         new = applyChange (fromString orig)
-                $ J.TextDocumentContentChangeEvent (mkRange 1 8 1 8) Nothing "\n-- fooo\nfoo :: Int"
+                $ J.TextDocumentContentChangeEvent (Just $ J.mkRange 1 8 1 8) Nothing "\n-- fooo\nfoo :: Int"
       lines (Rope.toString new) `shouldBe`
           [ "module Foo where"
           , "foo = bb"
@@ -218,7 +214,7 @@ vspSpec = do
           ]
         -- new = changeChars (fromString orig) (J.Position 7 0) (J.Position 7 8) "baz ="
         new = applyChange (fromString orig)
-                $ J.TextDocumentContentChangeEvent (mkRange 7 0 7 8) (Just 8) "baz ="
+                $ J.TextDocumentContentChangeEvent (Just $ J.mkRange 7 0 7 8) (Just 8) "baz ="
       lines (Rope.toString new) `shouldBe`
           [ "module Foo where"
           , "-- fooo"
@@ -246,7 +242,7 @@ vspSpec = do
           ]
         -- new = changeChars (fromString orig) (J.Position 7 0) (J.Position 7 8) "baz ="
         new = applyChange (fromString orig)
-                $ J.TextDocumentContentChangeEvent (mkRange 7 0 7 8) Nothing "baz ="
+                $ J.TextDocumentContentChangeEvent (Just $ J.mkRange 7 0 7 8) Nothing "baz ="
       lines (Rope.toString new) `shouldBe`
           [ "module Foo where"
           , "-- fooo"
@@ -265,7 +261,7 @@ vspSpec = do
           , "a𐐀b"
           ]
         new = applyChange (fromString orig)
-                $ J.TextDocumentContentChangeEvent (mkRange 1 0 1 3) (Just 3) "𐐀𐐀"
+                $ J.TextDocumentContentChangeEvent (Just $ J.mkRange 1 0 1 3) (Just 3) "𐐀𐐀"
       lines (Rope.toString new) `shouldBe`
           [ "a𐐀b"
           , "𐐀𐐀b"