diff --git a/ROADMAP.md b/ROADMAP.md
index 9e36f6aa3..3bed09a9e 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -1,5 +1,7 @@
 # Roadmap
 
+This is the long form version of our [roadmap project][].
+
 ## Things we are currently doing:
 
 1. [Diff summaries][] for C & JavaScript. Q3 2016 or so.
@@ -34,6 +36,7 @@
 2. Collect data on our heuristics &c. and refine them via e.g. ML.
 3. Diffs as a [service][].
 
+[roadmap project]: https://github.com/github/semantic-diff/projects/5
 [Diff summaries]: https://github.com/github/semantic-diff/milestones/Summer%20Eyes
 [Semantic diffs]: https://github.com/github/semantic-diff/milestones/Dot%20Calm
 [Ruby]: https://github.com/github/semantic-diff/issues/282
diff --git a/src/Alignment.hs b/src/Alignment.hs
index 1513ec0d2..5bdea0da6 100644
--- a/src/Alignment.hs
+++ b/src/Alignment.hs
@@ -38,15 +38,15 @@ numberedRows = countUp (both 1 1)
         nextLineNumbers from row = modifyJoin (fromThese identity identity) (succ <$ row) <*> from
 
 -- | Determine whether a line contains any patches.
-hasChanges :: SplitDiff leaf annotation -> Bool
+hasChanges :: (Prologue.Foldable f, Functor f) => SplitDiff f annotation -> Bool
 hasChanges = or . (True <$)
 
 -- | Align a Diff into a list of Join These SplitDiffs representing the (possibly blank) lines on either side.
-alignDiff :: HasField fields Range => Both (Source Char) -> Diff leaf (Record fields) -> [Join These (SplitDiff leaf (Record fields))]
+alignDiff :: HasField fields Range => Both (Source Char) -> SyntaxDiff leaf fields -> [Join These (SplitSyntaxDiff leaf fields)]
 alignDiff sources diff = iter (alignSyntax (runBothWith ((Join .) . These)) wrap getRange sources) (alignPatch sources <$> diff)
 
 -- | Align the contents of a patch into a list of lines on the corresponding side(s) of the diff.
-alignPatch :: forall fields leaf. HasField fields Range => Both (Source Char) -> Patch (Term leaf (Record fields)) -> [Join These (SplitDiff leaf (Record fields))]
+alignPatch :: forall fields leaf. HasField fields Range => Both (Source Char) -> Patch (SyntaxTerm leaf fields) -> [Join These (SplitSyntaxDiff leaf fields)]
 alignPatch sources patch = case patch of
   Delete term -> fmap (pure . SplitDelete) <$> alignSyntax' this (fst sources) term
   Insert term -> fmap (pure . SplitInsert) <$> alignSyntax' that (snd sources) term
@@ -54,13 +54,13 @@ alignPatch sources patch = case patch of
     (alignSyntax' this (fst sources) term1)
     (alignSyntax' that (snd sources) term2)
   where getRange = characterRange . extract
-        alignSyntax' :: (forall a. Identity a -> Join These a) -> Source Char -> Term leaf (Record fields) -> [Join These (Term leaf (Record fields))]
+        alignSyntax' :: (forall a. Identity a -> Join These a) -> Source Char -> SyntaxTerm leaf fields -> [Join These (SyntaxTerm leaf fields)]
         alignSyntax' side source term = hylo (alignSyntax side cofree getRange (Identity source)) runCofree (Identity <$> term)
         this = Join . This . runIdentity
         that = Join . That . runIdentity
 
 -- | The Applicative instance f is either Identity or Both. Identity is for Terms in Patches, Both is for Diffs in unchanged portions of the diff.
-alignSyntax :: (Applicative f, HasField fields Range) => (forall a. f a -> Join These a) -> (CofreeF (Syntax leaf) (Record fields) term -> term) -> (term -> Range) -> f (Source Char) -> CofreeF (Syntax leaf) (f (Record fields)) [Join These term] -> [Join These term]
+alignSyntax :: (Applicative f, HasField fields Range) => (forall a. f a -> Join These a) -> (SyntaxTermF leaf fields term -> term) -> (term -> Range) -> f (Source Char) -> TermF (Syntax leaf) (f (Record fields)) [Join These term] -> [Join These term]
 alignSyntax toJoinThese toNode getRange sources (infos :< syntax) = catMaybes $ case syntax of
   Leaf s -> wrapInBranch (const (Leaf s)) <$> alignBranch getRange [] bothRanges
   Syntax.Comment a -> wrapInBranch (const (Syntax.Comment a)) <$> alignBranch getRange [] bothRanges
diff --git a/src/Diff.hs b/src/Diff.hs
index ec56caac7..ec28dd2a4 100644
--- a/src/Diff.hs
+++ b/src/Diff.hs
@@ -6,35 +6,39 @@ import Prologue
 import Data.Functor.Foldable as Foldable
 import Data.Functor.Both as Both
 import Data.Mergeable
+import Data.Record
 import Patch
 import Syntax
 import Term
 
 -- | An annotated series of patches of terms.
-type DiffF leaf annotation = FreeF (CofreeF (Syntax leaf) (Both annotation)) (Patch (Term leaf annotation))
-type Diff a annotation = Free (CofreeF (Syntax a) (Both annotation)) (Patch (Term a annotation))
+type DiffF f annotation = FreeF (TermF f (Both annotation)) (Patch (Term f annotation))
+type Diff f annotation = Free (TermF f (Both annotation)) (Patch (Term f annotation))
+
+type SyntaxDiff leaf fields = Diff (Syntax leaf) (Record fields)
+
 
 type instance Base (Free f a) = FreeF f a
 instance Functor f => Foldable.Foldable (Free f a) where project = runFree
 instance Functor f => Foldable.Unfoldable (Free f a) where embed = free
 
-diffSum :: (Patch (Term a annotation) -> Int) -> Diff a annotation -> Int
+diffSum :: (Prologue.Foldable f, Functor f) => (Patch (Term f annotation) -> Int) -> Diff f annotation -> Int
 diffSum patchCost diff = sum $ fmap patchCost diff
 
 -- | The sum of the node count of the diff’s patches.
-diffCost :: Diff a annotation -> Int
+diffCost :: (Prologue.Foldable f, Functor f) => Diff f annotation -> Int
 diffCost = diffSum $ patchSum termSize
 
 -- | Merge a diff using a function to provide the Term (in Maybe, to simplify recovery of the before/after state) for every Patch.
-mergeMaybe :: (Patch (Term leaf annotation) -> Maybe (Term leaf annotation)) -> Diff leaf annotation -> Maybe (Term leaf annotation)
+mergeMaybe :: (Functor f, Mergeable f) => (Patch (Term f annotation) -> Maybe (Term f annotation)) -> Diff f annotation -> Maybe (Term f annotation)
 mergeMaybe transform = iter algebra . fmap transform
-  where algebra :: CofreeF (Syntax leaf) (Both annotation) (Maybe (Term leaf annotation)) -> Maybe (Term leaf annotation)
+  where algebra :: Mergeable f => TermF f (Both annotation) (Maybe (Term f annotation)) -> Maybe (Term f annotation)
         algebra (annotations :< syntax) = cofree . (Both.fst annotations :<) <$> sequenceAlt syntax
 
 -- | Recover the before state of a diff.
-beforeTerm :: Diff leaf annotation -> Maybe (Term leaf annotation)
+beforeTerm :: (Functor f, Mergeable f) => Diff f annotation -> Maybe (Term f annotation)
 beforeTerm = mergeMaybe before
 
 -- | Recover the after state of a diff.
-afterTerm :: Diff leaf annotation -> Maybe (Term leaf annotation)
+afterTerm :: (Functor f, Mergeable f) => Diff f annotation -> Maybe (Term f annotation)
 afterTerm = mergeMaybe after
diff --git a/src/Diff/Arbitrary.hs b/src/Diff/Arbitrary.hs
index b6fd009a4..66b5c2db3 100644
--- a/src/Diff/Arbitrary.hs
+++ b/src/Diff/Arbitrary.hs
@@ -3,11 +3,13 @@ module Diff.Arbitrary where
 import Diff
 import Data.Bifunctor.Join
 import Data.Bifunctor.Join.Arbitrary ()
+import Data.Functor.Both
 import Data.Functor.Foldable (unfold)
 import Patch
 import Patch.Arbitrary ()
 import Syntax
 import Prologue
+import Term
 import Term.Arbitrary
 import Test.QuickCheck hiding (Fixed)
 
@@ -16,11 +18,11 @@ data ArbitraryDiff leaf annotation
   | ArbitraryPure (Patch (ArbitraryTerm leaf annotation))
   deriving (Show, Eq, Generic)
 
-unArbitraryDiff :: ArbitraryDiff leaf annotation -> FreeF (CofreeF (Syntax leaf) (Join (,) annotation)) (Patch (ArbitraryTerm leaf annotation)) (ArbitraryDiff leaf annotation)
+unArbitraryDiff :: ArbitraryDiff leaf annotation -> FreeF (TermF (Syntax leaf) (Both annotation)) (Patch (ArbitraryTerm leaf annotation)) (ArbitraryDiff leaf annotation)
 unArbitraryDiff (ArbitraryFree a s) = Free (a :< s)
 unArbitraryDiff (ArbitraryPure p) = Pure p
 
-toDiff :: ArbitraryDiff leaf annotation -> Diff leaf annotation
+toDiff :: ArbitraryDiff leaf annotation -> Diff (Syntax leaf) annotation
 toDiff = fmap (fmap toTerm) . unfold unArbitraryDiff
 
 diffOfSize :: (Arbitrary leaf, Arbitrary annotation) => Int -> Gen (ArbitraryDiff leaf annotation)
diff --git a/src/DiffSummary.hs b/src/DiffSummary.hs
index c6f64a6f9..0dbae5c48 100644
--- a/src/DiffSummary.hs
+++ b/src/DiffSummary.hs
@@ -24,7 +24,7 @@ import Source
 
 data Identifiable a = Identifiable a | Unidentifiable a
 
-isIdentifiable :: (HasCategory leaf, HasField fields Category, HasField fields Range) => Term leaf (Record fields) -> Bool
+isIdentifiable :: (HasCategory leaf, HasField fields Category, HasField fields Range) => SyntaxTerm leaf fields -> Bool
 isIdentifiable term =
   case unwrap term of
     S.FunctionCall _ _ -> True
@@ -38,7 +38,7 @@ isIdentifiable term =
     S.Leaf _ -> True
     _ -> False
 
-identifiable :: (HasCategory leaf, HasField fields Category, HasField fields Range) => Term leaf (Record fields) -> Identifiable (Term leaf (Record fields))
+identifiable :: (HasCategory leaf, HasField fields Category, HasField fields Range) => SyntaxTerm leaf fields -> Identifiable (SyntaxTerm leaf fields)
 identifiable term = if isIdentifiable term then Identifiable term else Unidentifiable term
 
 data DiffInfo = LeafInfo { categoryName :: Text, termName :: Text }
@@ -54,7 +54,7 @@ data DiffSummary a = DiffSummary {
 } deriving (Eq, Functor, Show, Generic)
 
 -- Returns a list of diff summary texts given two source blobs and a diff.
-diffSummaries :: (HasCategory leaf, HasField fields Category, HasField fields Range) => Both SourceBlob -> Diff leaf (Record fields) -> [Either Text Text]
+diffSummaries :: (HasCategory leaf, HasField fields Category, HasField fields Range) => Both SourceBlob -> SyntaxDiff leaf fields -> [Either Text Text]
 diffSummaries blobs diff = summaryToTexts =<< diffToDiffSummaries (source <$> blobs) diff
 
 -- Takes a 'DiffSummary' and returns a list of summary texts representing the LeafInfos
@@ -63,7 +63,7 @@ summaryToTexts :: DiffSummary DiffInfo -> [Either Text Text]
 summaryToTexts DiffSummary{..} = runJoin . fmap (show . (P.<> maybeParentContext parentAnnotation)) <$> (Join <$> summaries patch)
 
 -- Returns a list of 'DiffSummary' given two source blobs and a diff.
-diffToDiffSummaries :: (HasCategory leaf, HasField fields Category, HasField fields Range) => Both (Source Char) -> Diff leaf (Record fields) -> [DiffSummary DiffInfo]
+diffToDiffSummaries :: (HasCategory leaf, HasField fields Category, HasField fields Range) => Both (Source Char) -> SyntaxDiff leaf fields -> [DiffSummary DiffInfo]
 diffToDiffSummaries sources = para $ \diff ->
   let diff' = free (Prologue.fst <$> diff)
       annotateWithCategory :: [(Diff leaf (Record fields), [DiffSummary DiffInfo])] -> [DiffSummary DiffInfo]
@@ -104,7 +104,7 @@ toLeafInfos BranchInfo{..} = toLeafInfos =<< branches
 toLeafInfos err@ErrorInfo{} = pure (pretty err)
 
 -- Returns a text representing a specific term given a source and a term.
-toTermName :: forall leaf fields. (HasCategory leaf, HasField fields Category, HasField fields Range) => Source Char -> Term leaf (Record fields) -> Text
+toTermName :: forall leaf fields. (HasCategory leaf, HasField fields Category, HasField fields Range) => Source Char -> SyntaxTerm leaf fields -> Text
 toTermName source term = case unwrap term of
   S.AnonymousFunction _ _ -> "anonymous"
   S.Fixed children -> fromMaybe "branch" $ (toCategoryName . category) . extract <$> head children
@@ -162,7 +162,7 @@ toTermName source term = case unwrap term of
         termNameFromSource term = termNameFromRange (range term)
         termNameFromRange range = toText $ Source.slice range source
         range = characterRange . extract
-        toArgName :: (HasCategory leaf, HasField fields Category, HasField fields Range) => Term leaf (Record fields) -> Text
+        toArgName :: (HasCategory leaf, HasField fields Category, HasField fields Range) => SyntaxTerm leaf fields -> Text
         toArgName arg = case identifiable arg of
                           Identifiable arg -> toTermName' arg
                           Unidentifiable _ -> "..."
@@ -174,7 +174,7 @@ maybeParentContext = maybe "" (\annotation ->
 toDoc :: Text -> Doc
 toDoc = string . toS
 
-termToDiffInfo :: (HasCategory leaf, HasField fields Category, HasField fields Range) => Source Char -> Term leaf (Record fields) -> DiffInfo
+termToDiffInfo :: (HasCategory leaf, HasField fields Category, HasField fields Range) => Source Char -> SyntaxTerm leaf fields -> DiffInfo
 termToDiffInfo blob term = case unwrap term of
   Leaf _ -> LeafInfo (toCategoryName term) (toTermName' term)
   S.AnonymousFunction _ _ -> LeafInfo (toCategoryName term) ("anonymous")
@@ -193,7 +193,7 @@ termToDiffInfo blob term = case unwrap term of
   where toTermName' = toTermName blob
         termToDiffInfo' = termToDiffInfo blob
 
-prependSummary :: (HasCategory leaf, HasField fields Range, HasField fields Category) => Source Char -> Term leaf (Record fields) -> DiffSummary DiffInfo -> DiffSummary DiffInfo
+prependSummary :: (HasCategory leaf, HasField fields Range, HasField fields Category) => Source Char -> SyntaxTerm leaf fields -> DiffSummary DiffInfo -> DiffSummary DiffInfo
 prependSummary source term summary =
   case (parentAnnotation summary, identifiable term) of
     (Nothing, Identifiable term) -> summary { parentAnnotation = Just (category . extract $ term, toTermName source term) }
@@ -270,7 +270,7 @@ instance HasCategory Category where
     C.CommaOperator -> "comma operator"
     C.Empty -> "empty statement"
 
-instance (HasCategory leaf, HasField fields Category) => HasCategory (Term leaf (Record fields)) where
+instance (HasCategory leaf, HasField fields Category) => HasCategory (SyntaxTerm leaf fields) where
   toCategoryName = toCategoryName . category . extract
 
 instance Arbitrary Branch where
diff --git a/src/Diffing.hs b/src/Diffing.hs
index 9e8ac983e..fa0f1eef3 100644
--- a/src/Diffing.hs
+++ b/src/Diffing.hs
@@ -93,7 +93,7 @@ parserForFilepath path blob = decorateTerm termCostDecorator <$> do
    pure $! breakDownLeavesByWord (source blob) parsed
 
 -- | Replace every string leaf with leaves of the words in the string.
-breakDownLeavesByWord :: (HasField fields Category, HasField fields Range) => Source Char -> Term Text (Record fields) -> Term Text (Record fields)
+breakDownLeavesByWord :: (HasField fields Category, HasField fields Range) => Source Char -> Term (Syntax Text) (Record fields) -> Term (Syntax Text) (Record fields)
 breakDownLeavesByWord source = cata replaceIn
   where
     replaceIn (info :< syntax) = cofree $ info :< syntax'
@@ -133,11 +133,11 @@ termCostDecorator :: (Prologue.Foldable f, Functor f) => TermDecorator f a Cost
 termCostDecorator c = 1 + sum (cost <$> tailF c)
 
 -- | Determine whether two terms are comparable based on the equality of their categories.
-compareCategoryEq :: HasField fields Category => Term leaf (Record fields) -> Term leaf (Record fields) -> Bool
+compareCategoryEq :: Functor f => HasField fields Category => Term f (Record fields) -> Term f (Record fields) -> Bool
 compareCategoryEq = (==) `on` category . extract
 
 -- | The sum of the node count of the diff’s patches.
-diffCostWithCachedTermCosts :: HasField fields Cost => Diff leaf (Record fields) -> Int
+diffCostWithCachedTermCosts :: Functor f => HasField fields Cost => Diff f (Record fields) -> Int
 diffCostWithCachedTermCosts diff = unCost $ case runFree diff of
   Free (info :< _) -> sum (cost <$> info)
   Pure patch -> sum (cost . extract <$> patch)
diff --git a/src/Interpreter.hs b/src/Interpreter.hs
index daf9eb6a8..74dc25408 100644
--- a/src/Interpreter.hs
+++ b/src/Interpreter.hs
@@ -19,23 +19,23 @@ import Syntax as S
 import Term
 
 -- | Returns whether two terms are comparable
-type Comparable leaf annotation = Term leaf annotation -> Term leaf annotation -> Bool
+type Comparable f annotation = Term f annotation -> Term f annotation -> Bool
 
 -- | Constructs a diff from the CofreeF containing its annotation and syntax. This function has the opportunity to, for example, cache properties in the annotation.
-type DiffConstructor leaf annotation = CofreeF (Syntax leaf) (Both annotation) (Diff leaf annotation) -> Diff leaf annotation
+type DiffConstructor f annotation = TermF f (Both annotation) (Diff f annotation) -> Diff f annotation
 
 -- | Diff two terms recursively, given functions characterizing the diffing.
 diffTerms :: (Eq leaf, Eq (Record fields), HasField fields Category, HasField fields (Vector.Vector Double))
-  => DiffConstructor leaf (Record fields) -- ^ A function to wrap up & possibly annotate every produced diff.
-  -> Comparable leaf (Record fields) -- ^ A function to determine whether or not two terms should even be compared.
-  -> SES.Cost (Diff leaf (Record fields)) -- ^ A function to compute the cost of a given diff node.
-  -> Term leaf (Record fields) -- ^ A term representing the old state.
-  -> Term leaf (Record fields) -- ^ A term representing the new state.
-  -> Diff leaf (Record fields)
+  => DiffConstructor (Syntax leaf) (Record fields) -- ^ A function to wrap up & possibly annotate every produced diff.
+  -> Comparable (Syntax leaf) (Record fields) -- ^ A function to determine whether or not two terms should even be compared.
+  -> SES.Cost (SyntaxDiff leaf fields) -- ^ A function to compute the cost of a given diff node.
+  -> SyntaxTerm leaf fields -- ^ A term representing the old state.
+  -> SyntaxTerm leaf fields -- ^ A term representing the new state.
+  -> SyntaxDiff leaf fields
 diffTerms construct comparable cost a b = fromMaybe (replacing a b) $ diffComparableTerms construct comparable cost a b
 
 -- | Diff two terms recursively, given functions characterizing the diffing. If the terms are incomparable, returns 'Nothing'.
-diffComparableTerms :: (Eq leaf, Eq (Record fields), HasField fields Category, HasField fields (Vector.Vector Double)) => DiffConstructor leaf (Record fields) -> Comparable leaf (Record fields) -> SES.Cost (Diff leaf (Record fields)) -> Term leaf (Record fields) -> Term leaf (Record fields) -> Maybe (Diff leaf (Record fields))
+diffComparableTerms :: (Eq leaf, Eq (Record fields), HasField fields Category, HasField fields (Vector.Vector Double)) => DiffConstructor (Syntax leaf) (Record fields) -> Comparable (Syntax leaf) (Record fields) -> SES.Cost (SyntaxDiff leaf fields) -> SyntaxTerm leaf fields -> SyntaxTerm leaf fields -> Maybe (SyntaxDiff leaf fields)
 diffComparableTerms construct comparable cost = recur
   where recur a b
           | (category <$> a) == (category <$> b) = hylo construct runCofree <$> zipTerms a b
@@ -43,7 +43,7 @@ diffComparableTerms construct comparable cost = recur
           | otherwise = Nothing
 
 -- | Construct an algorithm to diff a pair of terms.
-algorithmWithTerms :: (TermF leaf (Both a) diff -> diff) -> Term leaf a -> Term leaf a -> Algorithm (Term leaf a) diff diff
+algorithmWithTerms :: (TermF (Syntax leaf) (Both a) diff -> diff) -> Term (Syntax leaf) a -> Term (Syntax leaf) a -> Algorithm (Term (Syntax leaf) a) diff diff
 algorithmWithTerms construct t1 t2 = case (unwrap t1, unwrap t2) of
   (Indexed a, Indexed b) -> branch Indexed a b
   (S.FunctionCall identifierA argsA, S.FunctionCall identifierB argsB) -> do
diff --git a/src/Language.hs b/src/Language.hs
index 754ff2850..387db2570 100644
--- a/src/Language.hs
+++ b/src/Language.hs
@@ -43,8 +43,8 @@ termConstructor
   -> IO SourceSpan -- ^ The span that the term occupies. This is passed in 'IO' to guarantee some access constraints & encourage its use only when needed (improving performance).
   -> Text -- ^ The name of the production for this node.
   -> Range -- ^ The character range that the term occupies.
-  -> [Term Text (Record '[Range, Category])] -- ^ The child nodes of the term.
-  -> IO (Term Text (Record '[Range, Category])) -- ^ The resulting term, in IO.
+  -> [Term (S.Syntax Text) (Record '[Range, Category])] -- ^ The child nodes of the term.
+  -> IO (Term (S.Syntax Text) (Record '[Range, Category])) -- ^ The resulting term, in IO.
 termConstructor source sourceSpan name range children =
   withDefaultInfo <$> case (name, children) of
     ("ERROR", _) -> S.Error <$> sourceSpan <*> pure children
diff --git a/src/Language/C.hs b/src/Language/C.hs
index 81c0f4575..0cf8d2d52 100644
--- a/src/Language/C.hs
+++ b/src/Language/C.hs
@@ -6,6 +6,7 @@ import Info
 import Prologue
 import Source
 import SourceSpan
+import Syntax
 import qualified Syntax as S
 import Term
 
@@ -14,8 +15,8 @@ termConstructor
   -> IO SourceSpan -- ^ The span that the term occupies. This is passed in 'IO' to guarantee some access constraints & encourage its use only when needed (improving performance).
   -> Text -- ^ The name of the production for this node.
   -> Range -- ^ The character range that the term occupies.
-  -> [Term Text (Record '[Range, Category])] -- ^ The child nodes of the term.
-  -> IO (Term Text (Record '[Range, Category])) -- ^ The resulting term, in IO.
+  -> [Term (Syntax Text) (Record '[Range, Category])] -- ^ The child nodes of the term.
+  -> IO (Term (Syntax Text) (Record '[Range, Category])) -- ^ The resulting term, in IO.
 termConstructor source sourceSpan name range children
   | name == "ERROR" = sourceSpan >>= withDefaultInfo . (`S.Error` children)
   | otherwise = withDefaultInfo $ case (name, children) of
diff --git a/src/Language/JavaScript.hs b/src/Language/JavaScript.hs
index e38a5aee5..5be276759 100644
--- a/src/Language/JavaScript.hs
+++ b/src/Language/JavaScript.hs
@@ -23,8 +23,8 @@ termConstructor
   -> IO SourceSpan -- ^ The span that the term occupies. This is passed in 'IO' to guarantee some access constraints & encourage its use only when needed (improving performance).
   -> Text -- ^ The name of the production for this node.
   -> Range -- ^ The character range that the term occupies.
-  -> [Term Text (Record '[Range, Category])] -- ^ The child nodes of the term.
-  -> IO (Term Text (Record '[Range, Category])) -- ^ The resulting term, in IO.
+  -> [Term (S.Syntax Text) (Record '[Range, Category])] -- ^ The child nodes of the term.
+  -> IO (Term (S.Syntax Text) (Record '[Range, Category])) -- ^ The resulting term, in IO.
 termConstructor source sourceSpan name range children
   | name == "ERROR" = sourceSpan >>= withDefaultInfo . (`S.Error` children)
   | otherwise = withDefaultInfo $ case (name, children) of
@@ -141,10 +141,10 @@ categoryForJavaScriptProductionName name = case name of
   "rel_op" -> RelationalOperator
   _ -> Other name
 
-toVarDecl :: (HasField fields Category) => Term Text (Record fields) -> Term Text (Record fields)
+toVarDecl :: (HasField fields Category) => Term (S.Syntax Text) (Record fields) -> Term (S.Syntax Text) (Record fields)
 toVarDecl child = cofree $ (setCategory (extract child) VarDecl :< S.VarDecl child)
 
-toTuple :: Term Text (Record fields) -> [Term Text (Record fields)]
+toTuple :: Term (S.Syntax Text) (Record fields) -> [Term (S.Syntax Text) (Record fields)]
 toTuple child | S.Indexed [key,value] <- unwrap child = [cofree (extract child :< S.Pair key value)]
 toTuple child | S.Fixed [key,value] <- unwrap child = [cofree (extract child :< S.Pair key value)]
 toTuple child | S.Leaf c <- unwrap child = [cofree (extract child :< S.Comment c)]
diff --git a/src/Renderer.hs b/src/Renderer.hs
index 76a478517..22fe93452 100644
--- a/src/Renderer.hs
+++ b/src/Renderer.hs
@@ -1,16 +1,17 @@
 module Renderer (Renderer, DiffArguments(..), Output(..), concatOutputs, toSummaryKey, Format(..)) where
 
-import Prologue
-import Data.Functor.Both
-import Diff
-import Source (SourceBlob)
-import Data.Text as T (intercalate)
 import Data.Aeson (Value, toEncoding)
 import Data.Aeson.Encoding (encodingToLazyByteString)
+import Data.Functor.Both
 import Data.Map as Map hiding (null)
+import Data.Text as T (intercalate)
+import Diff
+import Prologue
+import Source (SourceBlob)
+import Syntax
 
 -- | A function that will render a diff, given the two source blobs.
-type Renderer annotation = Both SourceBlob -> Diff Text annotation -> Output
+type Renderer annotation = Both SourceBlob -> Diff (Syntax Text) annotation -> Output
 
 data DiffArguments = DiffArguments { format :: Format, output :: Maybe FilePath, outputPath :: FilePath }
  deriving (Show)
diff --git a/src/Renderer/JSON.hs b/src/Renderer/JSON.hs
index 7292fac1f..04d25ec37 100644
--- a/src/Renderer/JSON.hs
+++ b/src/Renderer/JSON.hs
@@ -32,7 +32,7 @@ json blobs diff = JSONOutput $ Map.fromList [
 -- | A numbered 'a'.
 newtype NumberedLine a = NumberedLine (Int, a)
 
-instance (HasField fields Category, HasField fields Range) => ToJSON (NumberedLine (SplitDiff leaf (Record fields))) where
+instance (HasField fields Category, HasField fields Range) => ToJSON (NumberedLine (SplitSyntaxDiff leaf fields)) where
   toJSON (NumberedLine (n, a)) = object (lineFields n a (getRange a))
   toEncoding (NumberedLine (n, a)) = pairs $ mconcat (lineFields n a (getRange a))
 instance ToJSON Category where
@@ -40,24 +40,24 @@ instance ToJSON Category where
   toJSON s = String . T.pack $ show s
 instance ToJSON Range where
   toJSON (Range start end) = A.Array . Vector.fromList $ toJSON <$> [ start, end ]
-  toEncoding (Range start end) = foldable [ start,  end ]
+  toEncoding (Range start end) = foldable [ start, end ]
 instance ToJSON a => ToJSON (Join These a) where
   toJSON (Join vs) = A.Array . Vector.fromList $ toJSON <$> these pure pure (\ a b -> [ a, b ]) vs
   toEncoding = foldable
 instance ToJSON a => ToJSON (Join (,) a) where
   toJSON (Join (a, b)) = A.Array . Vector.fromList $ toJSON <$> [ a, b ]
-instance (HasField fields Category, HasField fields Range) => ToJSON (SplitDiff leaf (Record fields)) where
+instance (HasField fields Category, HasField fields Range) => ToJSON (SplitSyntaxDiff leaf fields) where
   toJSON splitDiff = case runFree splitDiff of
     (Free (info :< syntax)) -> object (termFields info syntax)
     (Pure patch)            -> object (patchFields patch)
   toEncoding splitDiff = case runFree splitDiff of
     (Free (info :< syntax)) -> pairs $ mconcat (termFields info syntax)
     (Pure patch)            -> pairs $ mconcat (patchFields patch)
-instance (HasField fields Category, HasField fields Range) => ToJSON (Term leaf (Record fields)) where
+instance (HasField fields Category, HasField fields Range) => ToJSON (SyntaxTerm leaf fields) where
   toJSON term     | (info :< syntax) <- runCofree term = object (termFields info syntax)
   toEncoding term | (info :< syntax) <- runCofree term = pairs $ mconcat (termFields info syntax)
 
-lineFields :: (HasField fields Category, HasField fields Range) => KeyValue kv => Int -> SplitDiff leaf (Record fields) -> Range -> [kv]
+lineFields :: (HasField fields Category, HasField fields Range) => KeyValue kv => Int -> SplitSyntaxDiff leaf fields -> Range -> [kv]
 lineFields n term range = [ "number" .= n
                           , "terms" .= [ term ]
                           , "range" .= range
@@ -102,7 +102,7 @@ termFields info syntax = "range" .= characterRange info : "category" .= category
   S.Method identifier params definitions -> [ "methodIdentifier" .= identifier ] <> [ "params" .= params ] <> [ "definitions" .= definitions ]
   where childrenFields c = [ "children" .= c ]
 
-patchFields :: (KeyValue kv, HasField fields Category, HasField fields Range) => SplitPatch (Term leaf (Record fields)) -> [kv]
+patchFields :: (KeyValue kv, HasField fields Category, HasField fields Range) => SplitPatch (SyntaxTerm leaf fields) -> [kv]
 patchFields patch = case patch of
   SplitInsert term -> fields "insert" term
   SplitDelete term -> fields "delete" term
diff --git a/src/Renderer/Patch.hs b/src/Renderer/Patch.hs
index 27857ece7..afe474c42 100644
--- a/src/Renderer/Patch.hs
+++ b/src/Renderer/Patch.hs
@@ -53,7 +53,7 @@ rowIncrement :: Join These a -> Both (Sum Int)
 rowIncrement = Join . fromThese (Sum 0) (Sum 0) . runJoin . (Sum 1 <$)
 
 -- | Given the before and after sources, render a hunk to a string.
-showHunk :: HasField fields Range => Both SourceBlob -> Hunk (SplitDiff a (Record fields)) -> String
+showHunk :: Functor f => HasField fields Range => Both SourceBlob -> Hunk (SplitDiff f (Record fields)) -> String
 showHunk blobs hunk = maybeOffsetHeader <>
   concat (showChange sources <$> changes hunk) <>
   showLines (snd sources) ' ' (maybeSnd . runJoin <$> trailingContext hunk)
@@ -66,18 +66,18 @@ showHunk blobs hunk = maybeOffsetHeader <>
         (offsetA, offsetB) = runJoin . fmap (show . getSum) $ offset hunk
 
 -- | Given the before and after sources, render a change to a string.
-showChange :: HasField fields Range => Both (Source Char) -> Change (SplitDiff a (Record fields)) -> String
+showChange :: Functor f => HasField fields Range => Both (Source Char) -> Change (SplitDiff f (Record fields)) -> String
 showChange sources change = showLines (snd sources) ' ' (maybeSnd . runJoin <$> context change) <> deleted <> inserted
   where (deleted, inserted) = runJoin $ pure showLines <*> sources <*> both '-' '+' <*> Join (unzip (fromThese Nothing Nothing . runJoin . fmap Just <$> contents change))
 
 -- | Given a source, render a set of lines to a string with a prefix.
-showLines :: HasField fields Range => Source Char -> Char -> [Maybe (SplitDiff leaf (Record fields))] -> String
+showLines :: Functor f => HasField fields Range => Source Char -> Char -> [Maybe (SplitDiff f (Record fields))] -> String
 showLines source prefix lines = fromMaybe "" . mconcat $ fmap prepend . showLine source <$> lines
   where prepend "" = ""
         prepend source = prefix : source
 
 -- | Given a source, render a line to a string.
-showLine :: HasField fields Range => Source Char -> Maybe (SplitDiff leaf (Record fields)) -> Maybe String
+showLine :: Functor f => HasField fields Range => Source Char -> Maybe (SplitDiff f (Record fields)) -> Maybe String
 showLine source line | Just line <- line = Just . toString . (`slice` source) $ getRange line
                      | otherwise = Nothing
 
@@ -116,7 +116,7 @@ emptyHunk :: Hunk (SplitDiff a annotation)
 emptyHunk = Hunk { offset = mempty, changes = [], trailingContext = [] }
 
 -- | Render a diff as a series of hunks.
-hunks :: HasField fields Range => Diff a (Record fields) -> Both SourceBlob -> [Hunk (SplitDiff a (Record fields))]
+hunks :: HasField fields Range => SyntaxDiff leaf fields -> Both SourceBlob -> [Hunk (SplitSyntaxDiff leaf fields)]
 hunks _ blobs | sources <- source <$> blobs
               , sourcesEqual <- runBothWith (==) sources
               , sourcesNull <- runBothWith (&&) (null <$> sources)
@@ -126,14 +126,14 @@ hunks diff blobs = hunksInRows (pure 1) $ alignDiff (source <$> blobs) diff
 
 -- | Given beginning line numbers, turn rows in a split diff into hunks in a
 -- | patch.
-hunksInRows :: Both (Sum Int) -> [Join These (SplitDiff a annotation)] -> [Hunk (SplitDiff a annotation)]
+hunksInRows :: (Prologue.Foldable f, Functor f) => Both (Sum Int) -> [Join These (SplitDiff f annotation)] -> [Hunk (SplitDiff f annotation)]
 hunksInRows start rows = case nextHunk start rows of
   Nothing -> []
   Just (hunk, rest) -> hunk : hunksInRows (offset hunk <> hunkLength hunk) rest
 
 -- | Given beginning line numbers, return the next hunk and the remaining rows
 -- | of the split diff.
-nextHunk :: Both (Sum Int) -> [Join These (SplitDiff a annotation)] -> Maybe (Hunk (SplitDiff a annotation), [Join These (SplitDiff a annotation)])
+nextHunk :: (Prologue.Foldable f, Functor f) => Both (Sum Int) -> [Join These (SplitDiff f annotation)] -> Maybe (Hunk (SplitDiff f annotation), [Join These (SplitDiff f annotation)])
 nextHunk start rows = case nextChange start rows of
   Nothing -> Nothing
   Just (offset, change, rest) -> let (changes, rest') = contiguousChanges rest in Just (Hunk offset (change : changes) $ take 3 rest', drop 3 rest')
@@ -145,7 +145,7 @@ nextHunk start rows = case nextChange start rows of
 
 -- | Given beginning line numbers, return the number of lines to the next
 -- | the next change, and the remaining rows of the split diff.
-nextChange :: Both (Sum Int) -> [Join These (SplitDiff a annotation)] -> Maybe (Both (Sum Int), Change (SplitDiff a annotation), [Join These (SplitDiff a annotation)])
+nextChange :: (Prologue.Foldable f, Functor f) => Both (Sum Int) -> [Join These (SplitDiff f annotation)] -> Maybe (Both (Sum Int), Change (SplitDiff f annotation), [Join These (SplitDiff f annotation)])
 nextChange start rows = case changeIncludingContext leadingContext afterLeadingContext of
   Nothing -> Nothing
   Just (change, afterChanges) -> Just (start <> mconcat (rowIncrement <$> skippedContext), change, afterChanges)
@@ -155,12 +155,12 @@ nextChange start rows = case changeIncludingContext leadingContext afterLeadingC
 -- | Return a Change with the given context and the rows from the begginning of
 -- | the given rows that have changes, or Nothing if the first row has no
 -- | changes.
-changeIncludingContext :: [Join These (SplitDiff a annotation)] -> [Join These (SplitDiff a annotation)] -> Maybe (Change (SplitDiff a annotation), [Join These (SplitDiff a annotation)])
+changeIncludingContext :: (Prologue.Foldable f, Functor f) => [Join These (SplitDiff f annotation)] -> [Join These (SplitDiff f annotation)] -> Maybe (Change (SplitDiff f annotation), [Join These (SplitDiff f annotation)])
 changeIncludingContext leadingContext rows = case changes of
   [] -> Nothing
   _ -> Just (Change leadingContext changes, afterChanges)
   where (changes, afterChanges) = span rowHasChanges rows
 
 -- | Whether a row has changes on either side.
-rowHasChanges :: Join These (SplitDiff a annotation) -> Bool
+rowHasChanges :: (Prologue.Foldable f, Functor f) => Join These (SplitDiff f annotation) -> Bool
 rowHasChanges row = or (hasChanges <$> row)
diff --git a/src/Renderer/Split.hs b/src/Renderer/Split.hs
index 61fbb5831..40388b5d0 100644
--- a/src/Renderer/Split.hs
+++ b/src/Renderer/Split.hs
@@ -142,15 +142,15 @@ wrapIn f p = f p
 
 -- Instances
 
-instance (ToMarkup f, HasField fields Category, HasField fields Cost, HasField fields Range) => ToMarkup (Renderable (CofreeF (Syntax leaf) (Record fields) (f, Range))) where
+instance (ToMarkup f, HasField fields Category, HasField fields Cost, HasField fields Range) => ToMarkup (Renderable (SyntaxTermF leaf fields (f, Range))) where
   toMarkup (Renderable source (info :< syntax)) = classifyMarkup (category info) $ case syntax of
     Leaf _ -> span . string . toString $ slice (characterRange info) source
     _ -> ul . mconcat $ wrapIn li <$> contentElements source (characterRange info) (toList syntax)
 
-instance (HasField fields Category, HasField fields Cost, HasField fields Range) => ToMarkup (Renderable (Term leaf (Record fields))) where
+instance (HasField fields Category, HasField fields Cost, HasField fields Range) => ToMarkup (Renderable (SyntaxTerm leaf fields)) where
   toMarkup (Renderable source term) = Prologue.fst $ cata (\ t -> (toMarkup $ Renderable source t, characterRange (headF t))) term
 
-instance (HasField fields Category, HasField fields Cost, HasField fields Range) => ToMarkup (Renderable (SplitDiff leaf (Record fields))) where
+instance (HasField fields Category, HasField fields Cost, HasField fields Range) => ToMarkup (Renderable (SplitSyntaxDiff leaf fields)) where
   toMarkup (Renderable source diff) = Prologue.fst . iter (\ t -> (toMarkup $ Renderable source t, characterRange (headF t))) $ toMarkupAndRange <$> diff
     where toMarkupAndRange patch = let term@(info :< _) = runCofree $ getSplitTerm patch in
             ((div ! patchAttribute patch `withCostAttribute` cost info) . toMarkup $ Renderable source (cofree term), characterRange info)
diff --git a/src/SplitDiff.hs b/src/SplitDiff.hs
index be23cc521..f78b0ac2d 100644
--- a/src/SplitDiff.hs
+++ b/src/SplitDiff.hs
@@ -4,7 +4,7 @@ import Data.Record
 import Info
 import Prologue
 import Syntax
-import Term (Term)
+import Term (Term, TermF)
 
 -- | A patch to only one side of a diff.
 data SplitPatch a = SplitInsert a | SplitDelete a | SplitReplace a
@@ -17,10 +17,11 @@ getSplitTerm (SplitDelete a) = a
 getSplitTerm (SplitReplace a) = a
 
 -- | Get the range of a SplitDiff.
-getRange :: HasField fields Range => SplitDiff leaf (Record fields) -> Range
+getRange :: Functor f => HasField fields Range => SplitDiff f (Record fields) -> Range
 getRange diff = characterRange $ case runFree diff of
   Free annotated -> headF annotated
   Pure patch -> extract (getSplitTerm patch)
 
 -- | A diff with only one side’s annotations.
-type SplitDiff leaf annotation = Free (CofreeF (Syntax leaf) annotation) (SplitPatch (Term leaf annotation))
+type SplitDiff f annotation = Free (TermF f annotation) (SplitPatch (Term f annotation))
+type SplitSyntaxDiff leaf fields = SplitDiff (Syntax leaf) (Record fields)
diff --git a/src/Term.hs b/src/Term.hs
index ad7d49e5f..e08e836b9 100644
--- a/src/Term.hs
+++ b/src/Term.hs
@@ -6,36 +6,40 @@ import Prologue
 import Data.Align.Generic
 import Data.Functor.Foldable as Foldable
 import Data.Functor.Both
+import Data.Record
 import Data.These
 import Syntax
 
 -- | An annotated node (Syntax) in an abstract syntax tree.
-type TermF a annotation = CofreeF (Syntax a) annotation
-type Term a annotation = Cofree (Syntax a) annotation
+type TermF = CofreeF
+type Term f = Cofree f
 
-type instance Base (Cofree f a) = CofreeF f a
-instance Functor f => Foldable.Foldable (Cofree f a) where project = runCofree
-instance Functor f => Foldable.Unfoldable (Cofree f a) where embed = cofree
+type SyntaxTermF leaf fields = TermF (Syntax leaf) (Record fields)
+type SyntaxTerm leaf fields = Term (Syntax leaf) (Record fields)
+
+type instance Base (Term f a) = TermF f a
+instance Functor f => Foldable.Foldable (Term f a) where project = runCofree
+instance Functor f => Foldable.Unfoldable (Term f a) where embed = cofree
 
 -- | Zip two terms by combining their annotations into a pair of annotations.
 -- | If the structure of the two terms don't match, then Nothing will be returned.
 
-zipTerms :: (Eq a, Eq annotation) => Term a annotation -> Term a annotation -> Maybe (Term a (Both annotation))
+zipTerms :: (Eq annotation, Traversable f, GAlign f) => Term f annotation -> Term f annotation -> Maybe (Term f (Both annotation))
 zipTerms t1 t2 = iter go (alignCofreeWith galign (const Nothing) both (These t1 t2))
   where go (a :< s) = cofree . (a :<) <$> sequenceA s
 
 -- | Return the node count of a term.
-termSize :: (Prologue.Foldable f, Functor f) => Cofree f annotation -> Int
+termSize :: (Prologue.Foldable f, Functor f) => Term f annotation -> Int
 termSize = cata size where
   size (_ :< syntax) = 1 + sum syntax
 
 -- | Aligns (zips, retaining non-overlapping portions of the structure) a pair of terms.
 alignCofreeWith :: Functor f
   => (forall a b. f a -> f b -> Maybe (f (These a b))) -- ^ A function comparing a pair of structures, returning `Just` the combined structure if they are comparable (e.g. if they have the same constructor), and `Nothing` otherwise. The 'Data.Align.Generic.galign' function is usually what you want here.
-  -> (These (Cofree f a) (Cofree f b) -> contrasted) -- ^ A function mapping a 'These' of incomparable terms into 'Pure' values in the resulting tree.
+  -> (These (Term f a) (Term f b) -> contrasted) -- ^ A function mapping a 'These' of incomparable terms into 'Pure' values in the resulting tree.
   -> (a -> b -> combined) -- ^ A function mapping the input terms’ annotations into annotations in the 'Free' values in the resulting tree.
-  -> These (Cofree f a) (Cofree f b) -- ^ The input terms.
-  -> Free (CofreeF f combined) contrasted
+  -> These (Term f a) (Term f b) -- ^ The input terms.
+  -> Free (TermF f combined) contrasted
 alignCofreeWith compare contrast combine = go
   where go terms = fromMaybe (pure (contrast terms)) $ case terms of
           These t1 t2 -> wrap . (combine (extract t1) (extract t2) :<) . fmap go <$> compare (unwrap t1) (unwrap t2)
diff --git a/src/Term/Arbitrary.hs b/src/Term/Arbitrary.hs
index c79b572b7..2f34c8454 100644
--- a/src/Term/Arbitrary.hs
+++ b/src/Term/Arbitrary.hs
@@ -11,10 +11,10 @@ import Test.QuickCheck hiding (Fixed)
 data ArbitraryTerm leaf annotation = ArbitraryTerm { annotation :: annotation, syntax :: Syntax leaf (ArbitraryTerm leaf annotation)}
   deriving (Show, Eq, Generic)
 
-unArbitraryTerm :: ArbitraryTerm leaf annotation -> TermF leaf annotation (ArbitraryTerm leaf annotation)
+unArbitraryTerm :: ArbitraryTerm leaf annotation -> TermF (Syntax leaf) annotation (ArbitraryTerm leaf annotation)
 unArbitraryTerm (ArbitraryTerm a s) = a :< s
 
-toTerm :: ArbitraryTerm leaf annotation -> Term leaf annotation
+toTerm :: ArbitraryTerm leaf annotation -> Term (Syntax leaf) annotation
 toTerm = unfold unArbitraryTerm
 
 termOfSize :: (Arbitrary leaf, Arbitrary annotation) => Int -> Gen (ArbitraryTerm leaf annotation)
@@ -26,7 +26,7 @@ arbitraryTermSize = cata (succ . sum) . toTerm
 
 -- Instances
 
-type instance Base (ArbitraryTerm leaf annotation) = TermF leaf annotation
+type instance Base (ArbitraryTerm leaf annotation) = TermF (Syntax leaf) annotation
 instance Unfoldable (ArbitraryTerm leaf annotation) where embed (a :< s) = ArbitraryTerm a s
 
 instance (Eq leaf, Eq annotation, Arbitrary leaf, Arbitrary annotation) => Arbitrary (ArbitraryTerm leaf annotation) where
diff --git a/test/AlignmentSpec.hs b/test/AlignmentSpec.hs
index e9f4f2e07..3a64abdca 100644
--- a/test/AlignmentSpec.hs
+++ b/test/AlignmentSpec.hs
@@ -32,7 +32,7 @@ spec :: Spec
 spec = parallel $ do
   describe "alignBranch" $ do
     it "produces symmetrical context" $
-      alignBranch getRange ([] :: [Join These (SplitDiff String (Record '[Range]))]) (both [Range 0 2, Range 2 4] [Range 0 2, Range 2 4]) `shouldBe`
+      alignBranch getRange ([] :: [Join These (SplitDiff (Syntax String) (Record '[Range]))]) (both [Range 0 2, Range 2 4] [Range 0 2, Range 2 4]) `shouldBe`
         [ Join (These (Range 0 2, [])
                       (Range 0 2, []))
         , Join (These (Range 2 4, [])
@@ -40,7 +40,7 @@ spec = parallel $ do
         ]
 
     it "produces asymmetrical context" $
-      alignBranch getRange ([] :: [Join These (SplitDiff String (Record '[Range]))]) (both [Range 0 2, Range 2 4] [Range 0 1]) `shouldBe`
+      alignBranch getRange ([] :: [Join These (SplitDiff (Syntax String) (Record '[Range]))]) (both [Range 0 2, Range 2 4] [Range 0 1]) `shouldBe`
         [ Join (These (Range 0 2, [])
                       (Range 0 1, []))
         , Join (This  (Range 2 4, []))
@@ -231,7 +231,7 @@ toAlignBranchInputs elements = (sources, join . (`evalState` both 0 0) . travers
         branchElementContents (Margin contents) = contents
 
 keysOfAlignedChildren :: [Join These (Range, [(String, Range)])] -> [String]
-keysOfAlignedChildren lines = lines >>= these identity identity (++) . runJoin . fmap (fmap Prologue.fst . Prologue.snd)
+keysOfAlignedChildren lines = lines >>= these identity identity (<>) . runJoin . fmap (fmap Prologue.fst . Prologue.snd)
 
 joinCrosswalk :: Bicrosswalk p => Align f => (a -> f b) -> Join p a -> f (Join p b)
 joinCrosswalk f = fmap Join . bicrosswalk f f . runJoin
@@ -257,13 +257,13 @@ instance Arbitrary BranchElement where
 counts :: [Join These (Int, a)] -> Both Int
 counts numbered = fromMaybe 0 . getLast . mconcat . fmap Last <$> Join (unalign (runJoin . fmap Prologue.fst <$> numbered))
 
-align :: Both (Source.Source Char) -> ConstructibleFree (Patch (Term String (Record '[Range]))) (Both (Record '[Range])) -> PrettyDiff (SplitDiff String (Record '[Range]))
+align :: Both (Source.Source Char) -> ConstructibleFree (Patch (Term (Syntax String) (Record '[Range]))) (Both (Record '[Range])) -> PrettyDiff (SplitDiff (Syntax String) (Record '[Range]))
 align sources = PrettyDiff sources . fmap (fmap (getRange &&& identity)) . alignDiff sources . deconstruct
 
 info :: Int -> Int -> Record '[Range]
 info start end = Range start end .: RNil
 
-prettyDiff :: Both (Source.Source Char) -> [Join These (ConstructibleFree (SplitPatch (Term String (Record '[Range]))) (Record '[Range]))] -> PrettyDiff (SplitDiff String (Record '[Range]))
+prettyDiff :: Both (Source.Source Char) -> [Join These (ConstructibleFree (SplitPatch (Term (Syntax String) (Record '[Range]))) (Record '[Range]))] -> PrettyDiff (SplitDiff (Syntax String) (Record '[Range]))
 prettyDiff sources = PrettyDiff sources . fmap (fmap ((getRange &&& identity) . deconstruct))
 
 data PrettyDiff a = PrettyDiff { unPrettySources :: Both (Source.Source Char), unPrettyLines :: [Join These (Range, a)] }
@@ -273,23 +273,23 @@ instance Show a => Show (PrettyDiff a) where
   showsPrec _ (PrettyDiff sources lines) = (prettyPrinted ++) -- . (("\n" ++ show lines) ++)
     where prettyPrinted = showLine (maximum (0 : (maximum . fmap length <$> shownLines))) <$> shownLines >>= ('\n':)
           shownLines = catMaybes $ toBoth <$> lines
-          showLine n line = uncurry ((++) . (++ " | ")) (fromThese (replicate n ' ') (replicate n ' ') (runJoin (pad n <$> line)))
+          showLine n line = uncurry ((<>) . (++ " | ")) (fromThese (replicate n ' ') (replicate n ' ') (runJoin (pad n <$> line)))
           showDiff (range, _) = filter (/= '\n') . toList . Source.slice range
-          pad n string = (++) (take n string) (replicate (max 0 (n - length string)) ' ')
+          pad n string = (<>) (take n string) (replicate (max 0 (n - length string)) ' ')
           toBoth them = showDiff <$> them `applyThese` modifyJoin (uncurry These) sources
 
 newtype ConstructibleFree patch annotation = ConstructibleFree { deconstruct :: Free (CofreeF (Syntax String) annotation) patch }
 
 
 class PatchConstructible p where
-  insert :: Term String (Record '[Range]) -> p
-  delete :: Term String (Record '[Range]) -> p
+  insert :: Term (Syntax String) (Record '[Range]) -> p
+  delete :: Term (Syntax String) (Record '[Range]) -> p
 
-instance PatchConstructible (Patch (Term String (Record '[Range]))) where
+instance PatchConstructible (Patch (Term (Syntax String) (Record '[Range]))) where
   insert = Insert
   delete = Delete
 
-instance PatchConstructible (SplitPatch (Term String (Record '[Range]))) where
+instance PatchConstructible (SplitPatch (Term (Syntax String) (Record '[Range]))) where
   insert = SplitInsert
   delete = SplitDelete
 
diff --git a/test/Data/RandomWalkSimilarity/Spec.hs b/test/Data/RandomWalkSimilarity/Spec.hs
index 118e72898..66e68f006 100644
--- a/test/Data/RandomWalkSimilarity/Spec.hs
+++ b/test/Data/RandomWalkSimilarity/Spec.hs
@@ -21,14 +21,14 @@ spec = parallel $ do
   let positively = succ . abs
   describe "pqGramDecorator" $ do
     prop "produces grams with stems of the specified length" $
-      \ (term, p, q) -> pqGramDecorator (rhead . headF) (positively p) (positively q) (toTerm term :: Term Text (Record '[Text])) `shouldSatisfy` all ((== (positively p)) . length . stem . rhead)
+      \ (term, p, q) -> pqGramDecorator (rhead . headF) (positively p) (positively q) (toTerm term :: Term (Syntax Text) (Record '[Text])) `shouldSatisfy` all ((== (positively p)) . length . stem . rhead)
 
     prop "produces grams with bases of the specified width" $
-      \ (term, p, q) -> pqGramDecorator (rhead . headF) (positively p) (positively q) (toTerm term :: Term Text (Record '[Text])) `shouldSatisfy` all ((== (positively q)) . length . base . rhead)
+      \ (term, p, q) -> pqGramDecorator (rhead . headF) (positively p) (positively q) (toTerm term :: Term (Syntax Text) (Record '[Text])) `shouldSatisfy` all ((== (positively q)) . length . base . rhead)
 
   describe "featureVectorDecorator" $ do
     prop "produces a vector of the specified dimension" $
-      \ (term, p, q, d) -> featureVectorDecorator (rhead . headF) (positively p) (positively q) (positively d) (toTerm term :: Term Text (Record '[Text])) `shouldSatisfy` all ((== (positively d)) . length . rhead)
+      \ (term, p, q, d) -> featureVectorDecorator (rhead . headF) (positively p) (positively q) (positively d) (toTerm term :: Term (Syntax Text) (Record '[Text])) `shouldSatisfy` all ((== (positively d)) . length . rhead)
 
   describe "rws" $ do
     let decorate = defaultFeatureVectorDecorator (category . headF)
diff --git a/test/DiffSummarySpec.hs b/test/DiffSummarySpec.hs
index d0d950dbf..f96bb5eed 100644
--- a/test/DiffSummarySpec.hs
+++ b/test/DiffSummarySpec.hs
@@ -26,7 +26,7 @@ arrayInfo = ArrayLiteral .: Range 0 3 .: RNil
 literalInfo :: Record '[Category, Range]
 literalInfo = StringLiteral .: Range 1 2 .: RNil
 
-testDiff :: Diff Text (Record '[Category, Range])
+testDiff :: Diff (Syntax Text) (Record '[Category, Range])
 testDiff = free $ Free (pure arrayInfo :< Indexed [ free $ Pure (Insert (cofree $ literalInfo :< Leaf "a")) ])
 
 testSummary :: DiffSummary DiffInfo
@@ -67,7 +67,7 @@ spec = parallel $ do
         extractLeaves (BranchInfo children _ _) = join $ extractLeaves <$> children
         extractLeaves leaf = [ leaf ]
 
-        extractDiffLeaves :: Term Text (Record '[Category, Range]) -> [ Term Text (Record '[Category, Range]) ]
+        extractDiffLeaves :: Term (Syntax Text) (Record '[Category, Range]) -> [ Term (Syntax Text) (Record '[Category, Range]) ]
         extractDiffLeaves term = case unwrap term of
           (Indexed children) -> join $ extractDiffLeaves <$> children
           (Fixed children) -> join $ extractDiffLeaves <$> children
@@ -81,7 +81,7 @@ spec = parallel $ do
                in
                 length listOfLeaves `shouldBe` length listOfDiffLeaves
 
-isIndexedOrFixed :: Patch (Term a annotation) -> Bool
+isIndexedOrFixed :: Patch (Term (Syntax a) annotation) -> Bool
 isIndexedOrFixed = any (isIndexedOrFixed' . unwrap)
 
 isIndexedOrFixed' :: Syntax a f -> Bool
diff --git a/vendor/text-icu b/vendor/text-icu
index 6d07c2b20..3ba9cfc43 160000
--- a/vendor/text-icu
+++ b/vendor/text-icu
@@ -1 +1 @@
-Subproject commit 6d07c2b2034f2bfdcd038de0d6a3ceca445f0221
+Subproject commit 3ba9cfc432eb9ee9193e453120b200fa01d6c664