diff --git a/.github/workflows/haskell.yml b/.github/workflows/haskell.yml
index 9ddfbf561..96a2a4cbb 100644
--- a/.github/workflows/haskell.yml
+++ b/.github/workflows/haskell.yml
@@ -11,14 +11,14 @@ on:
 jobs:
   build:
     name: ghc ${{ matrix.ghc }}
-    runs-on: ubuntu-16.04
+    runs-on: ubuntu-latest
     strategy:
       matrix:
         ghc: ["8.8.1"]
         cabal: ["3.0"]
 
     steps:
-    - uses: actions/checkout@master
+    - uses: actions/checkout@v2
       if: github.event.action == 'opened' || github.event.action == 'synchronize' || github.event.ref == 'refs/heads/master'
 
     - uses: actions/setup-haskell@v1
@@ -27,12 +27,6 @@ jobs:
         ghc-version: ${{ matrix.ghc }}
         cabal-version: ${{ matrix.cabal }}
 
-    - uses: actions/cache@v1
-      name: Cache ~/.cabal/packages
-      with:
-        path: ~/.cabal/packages
-        key: ${{ runner.os }}-${{ matrix.ghc }}-v1-cabal-packages
-
     - uses: actions/cache@v1
       name: Cache ~/.cabal/store
       with:
@@ -43,13 +37,13 @@ jobs:
       name: Cache dist-newstyle
       with:
         path: dist-newstyle
-        key: ${{ runner.os }}-${{ matrix.ghc }}-semantic-dist
+        key: ${{ runner.os }}-${{ matrix.ghc }}-${{ matrix.cabal }}-semantic-dist
 
     - name: Install dependencies
       run: |
         cabal v2-update
         cabal v2-configure --disable-optimization --enable-benchmarks --enable-tests --write-ghc-environment-files=always -j2
-        cabal v2-build --only-dependencies
+        cabal v2-build all --only-dependencies
 
     - name: hlint
       run: |
diff --git a/bench/Main.hs b/bench/Main.hs
index c005439a0..c1f6ca1ff 100644
--- a/bench/Main.hs
+++ b/bench/Main.hs
@@ -2,8 +2,10 @@ module Main (main) where
 
 import Gauge
 import qualified Evaluation
+import qualified Tagging
 
 main :: IO ()
 main = defaultMain
-  [ Evaluation.benchmarks
+  [ Tagging.benchmarks
+  , Evaluation.benchmarks
   ]
diff --git a/bench/Tagging.hs b/bench/Tagging.hs
new file mode 100644
index 000000000..b4386cba6
--- /dev/null
+++ b/bench/Tagging.hs
@@ -0,0 +1,97 @@
+{-# LANGUAGE FlexibleContexts  #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE TypeApplications  #-}
+
+module Tagging (benchmarks) where
+
+import           Control.Carrier.Parse.Measured
+import           Control.Carrier.Reader
+import           Control.Exception (throwIO)
+import           Control.Monad
+import           Data.Blob
+import           Data.Foldable
+import           Data.Language (LanguageMode (..), PerLanguageModes (..))
+import           Gauge
+import           System.FilePath.Glob
+import qualified System.Path as Path
+
+import Data.Flag
+import Proto.Semantic as P hiding (Blob, BlobPair)
+import Semantic.Api.Symbols (parseSymbols)
+import Semantic.Config as Config
+import Semantic.Task
+import Semantic.Task.Files
+
+benchmarks :: Benchmark
+benchmarks = bgroup "tagging"
+  [ pythonBenchmarks
+  , goBenchmarks
+  , rubyBenchmarks
+  ]
+
+pythonBenchmarks :: Benchmark
+pythonBenchmarks = bgroup "python"
+  [ bench "precise" $ runTagging preciseLanguageModes pyDir "*.py"
+  , bench "a la carte" $ runTagging aLaCarteLanguageModes pyDir "*.py"
+  ]
+  where pyDir = Path.relDir "tmp/python-examples/keras/keras"
+
+goBenchmarks :: Benchmark
+goBenchmarks = bgroup "go"
+  [ bench "precise" $ runTagging preciseLanguageModes dir "*.go"
+  , bench "a la carte" $ runTagging aLaCarteLanguageModes dir "*.go"
+  ]
+  where dir = Path.relDir "tmp/go-examples/go/src/database/sql"
+
+rubyBenchmarks :: Benchmark
+rubyBenchmarks = bgroup "ruby"
+  [ bench "precise" $ runTagging preciseLanguageModes dir "*.rb"
+  , bench "a la carte" $ runTagging aLaCarteLanguageModes dir "*.rb"
+  ]
+  where dir = Path.relDir "tmp/ruby-examples/ruby_spec/command_line"
+
+runTagging :: PerLanguageModes -> Path.RelDir -> String -> Benchmarkable
+runTagging mode dir glob = nfIO . withOptions testOptions $ \ config logger statter -> do
+  let session = TaskSession config "-" False logger statter
+  files <- globDir1 (compile glob) (Path.toString dir)
+  let paths = Path.relFile <$> files
+  for_ paths (runTask session . runParse . parseSymbolsFilePath mode >=> either throwIO pure)
+
+parseSymbolsFilePath ::
+  ( Has (Error SomeException) sig m
+  , Has Distribute sig m
+  , Has Parse sig m
+  , Has Files sig m
+  )
+  => PerLanguageModes
+  -> Path.RelFile
+  -> m ParseTreeSymbolResponse
+parseSymbolsFilePath languageModes path = readBlob (fileForTypedPath path) >>= runReader languageModes . parseSymbols . pure @[]
+
+aLaCarteLanguageModes :: PerLanguageModes
+aLaCarteLanguageModes = PerLanguageModes
+  { pythonMode = ALaCarte
+  , rubyMode = ALaCarte
+  , goMode = ALaCarte
+  , typescriptMode = ALaCarte
+  , tsxMode = ALaCarte
+  , javascriptMode = ALaCarte
+  , jsxMode = ALaCarte
+  }
+
+preciseLanguageModes :: PerLanguageModes
+preciseLanguageModes = PerLanguageModes
+  { pythonMode = Precise
+  , rubyMode = Precise
+  , goMode = Precise
+  , typescriptMode = Precise
+  , tsxMode = Precise
+  , javascriptMode = Precise
+  , jsxMode = Precise
+  }
+
+testOptions :: Config.Options
+testOptions = defaultOptions
+  { optionsFailOnWarning = flag FailOnWarning True
+  , optionsLogLevel = Nothing
+  }
diff --git a/semantic-ast/semantic-ast.cabal b/semantic-ast/semantic-ast.cabal
index 20cad3ca5..4689b103c 100644
--- a/semantic-ast/semantic-ast.cabal
+++ b/semantic-ast/semantic-ast.cabal
@@ -41,9 +41,9 @@ library
   -- other-modules:
   -- other-extensions:
   build-depends:       base ^>= 4.13
-                     , tree-sitter ^>= 0.7.2
+                     , tree-sitter ^>= 0.8
                      , semantic-source ^>= 0.0
-                     , tree-sitter-python ^>= 0.8
+                     , tree-sitter-python ^>= 0.8.1
                      , bytestring ^>= 0.10.8.2
                      , optparse-applicative >= 0.14.3 && < 0.16
                      , pretty-simple ^>= 3.1.0.0
diff --git a/semantic-go/semantic-go.cabal b/semantic-go/semantic-go.cabal
index 2c150980b..42ce5c561 100644
--- a/semantic-go/semantic-go.cabal
+++ b/semantic-go/semantic-go.cabal
@@ -28,8 +28,8 @@ common haskell
                      , semantic-source ^>= 0.0
                      , semantic-tags ^>= 0.0
                      , text ^>= 1.2.3
-                     , tree-sitter ^>= 0.7.2
-                     , tree-sitter-go ^>= 0.4
+                     , tree-sitter ^>= 0.8
+                     , tree-sitter-go ^>= 0.4.1
 
   ghc-options:
     -Weverything
diff --git a/semantic-go/src/Language/Go.hs b/semantic-go/src/Language/Go.hs
index c88ba65c7..38bf2e79f 100644
--- a/semantic-go/src/Language/Go.hs
+++ b/semantic-go/src/Language/Go.hs
@@ -5,6 +5,7 @@ module Language.Go
 ) where
 
 
+import           Data.Proxy
 import qualified Language.Go.Tags as GoTags
 import qualified Tags.Tagging.Precise as Tags
 import qualified TreeSitter.Go (tree_sitter_go)
@@ -13,8 +14,12 @@ import qualified TreeSitter.Unmarshal as TS
 
 newtype Term a = Term { getTerm :: Go.SourceFile a }
 
+instance TS.SymbolMatching Term where
+  matchedSymbols _ = TS.matchedSymbols (Proxy :: Proxy Go.SourceFile)
+  showFailure _ = TS.showFailure (Proxy :: Proxy Go.SourceFile)
+
 instance TS.Unmarshal Term where
-  unmarshalNode node = Term <$> TS.unmarshalNode node
+  matchers = fmap (fmap (TS.hoist Term)) TS.matchers
 
 instance Tags.ToTags Term where
   tags src = Tags.runTagging src . GoTags.tags . getTerm
diff --git a/semantic-java/semantic-java.cabal b/semantic-java/semantic-java.cabal
index 58901bc67..ce18f09d8 100644
--- a/semantic-java/semantic-java.cabal
+++ b/semantic-java/semantic-java.cabal
@@ -27,8 +27,8 @@ library
     , fused-effects    ^>= 1.0
     , semantic-source  ^>= 0.0
     , semantic-tags    ^>= 0.0
-    , tree-sitter      ^>= 0.7.2
-    , tree-sitter-java ^>= 0.6
+    , tree-sitter      ^>= 0.8
+    , tree-sitter-java ^>= 0.6.1
   hs-source-dirs:      src
   default-language:    Haskell2010
   ghc-options:
diff --git a/semantic-java/src/Language/Java.hs b/semantic-java/src/Language/Java.hs
index fc1365ea6..70a449cf7 100644
--- a/semantic-java/src/Language/Java.hs
+++ b/semantic-java/src/Language/Java.hs
@@ -4,6 +4,7 @@ module Language.Java
 , TreeSitter.Java.tree_sitter_java
 ) where
 
+import           Data.Proxy
 import qualified Language.Java.Tags as JavaTags
 import qualified Tags.Tagging.Precise as Tags
 import qualified TreeSitter.Java (tree_sitter_java)
@@ -12,8 +13,12 @@ import qualified TreeSitter.Unmarshal as TS
 
 newtype Term a = Term { getTerm :: Java.Program a }
 
+instance TS.SymbolMatching Term where
+  matchedSymbols _ = TS.matchedSymbols (Proxy :: Proxy Java.Program)
+  showFailure _ = TS.showFailure (Proxy :: Proxy Java.Program)
+
 instance TS.Unmarshal Term where
-  unmarshalNode node = Term <$> TS.unmarshalNode node
+  matchers = fmap (fmap (TS.hoist Term)) TS.matchers
 
 instance Tags.ToTags Term where
   tags src = Tags.runTagging src . JavaTags.tags . getTerm
diff --git a/semantic-json/semantic-json.cabal b/semantic-json/semantic-json.cabal
index e35406520..8096aeb1a 100644
--- a/semantic-json/semantic-json.cabal
+++ b/semantic-json/semantic-json.cabal
@@ -24,8 +24,8 @@ library
   build-depends:
       base              >= 4.13 && < 5
     , semantic-tags    ^>= 0.0
-    , tree-sitter      ^>= 0.7.2
-    , tree-sitter-json ^>= 0.5
+    , tree-sitter      ^>= 0.8
+    , tree-sitter-json ^>= 0.6
   hs-source-dirs:      src
   default-language:    Haskell2010
   ghc-options:
diff --git a/semantic-json/src/Language/JSON.hs b/semantic-json/src/Language/JSON.hs
index f4b9142a6..8768226c7 100644
--- a/semantic-json/src/Language/JSON.hs
+++ b/semantic-json/src/Language/JSON.hs
@@ -4,6 +4,7 @@ module Language.JSON
 , TreeSitter.JSON.tree_sitter_json
 ) where
 
+import           Data.Proxy
 import qualified Tags.Tagging.Precise as Tags
 import qualified TreeSitter.JSON (tree_sitter_json)
 import qualified TreeSitter.JSON.AST as JSON
@@ -11,8 +12,12 @@ import qualified TreeSitter.Unmarshal as TS
 
 newtype Term a = Term { getTerm :: JSON.Document a }
 
+instance TS.SymbolMatching Term where
+  matchedSymbols _ = TS.matchedSymbols (Proxy :: Proxy JSON.Document)
+  showFailure _ = TS.showFailure (Proxy :: Proxy JSON.Document)
+
 instance TS.Unmarshal Term where
-  unmarshalNode node = Term <$> TS.unmarshalNode node
+  matchers = fmap (fmap (TS.hoist Term)) TS.matchers
 
 -- | Tags aren’t really meaningful for JSON, but by implementing this we can avoid having to customize the set of parsers used for computing tags.
 instance Tags.ToTags Term where
diff --git a/semantic-python/semantic-python.cabal b/semantic-python/semantic-python.cabal
index a7b44f2b8..bcc3450d7 100644
--- a/semantic-python/semantic-python.cabal
+++ b/semantic-python/semantic-python.cabal
@@ -30,8 +30,9 @@ common haskell
                      , semantic-scope-graph ^>= 0.0
                      , semilattices ^>= 0
                      , text ^>= 1.2.3
-                     , tree-sitter ^>= 0.7.2
-                     , tree-sitter-python ^>= 0.8
+                     , tree-sitter ^>= 0.8
+                     , tree-sitter-python ^>= 0.8.1
+
   ghc-options:
     -Weverything
     -Wno-missing-local-signatures
diff --git a/semantic-python/src/Language/Python.hs b/semantic-python/src/Language/Python.hs
index 6a3b55dd3..3217a7589 100644
--- a/semantic-python/src/Language/Python.hs
+++ b/semantic-python/src/Language/Python.hs
@@ -4,7 +4,7 @@ module Language.Python
 , TreeSitter.Python.tree_sitter_python
 ) where
 
-import           Language.Python.ScopeGraph
+import           Data.Proxy
 import qualified Language.Python.Tags as PyTags
 import           ScopeGraph.Convert
 import qualified Tags.Tagging.Precise as Tags
@@ -14,8 +14,12 @@ import qualified TreeSitter.Unmarshal as TS
 
 newtype Term a = Term { getTerm :: Py.Module a }
 
+instance TS.SymbolMatching Term where
+  matchedSymbols _ = TS.matchedSymbols (Proxy :: Proxy Py.Module)
+  showFailure _ = TS.showFailure (Proxy :: Proxy Py.Module)
+
 instance TS.Unmarshal Term where
-  unmarshalNode node = Term <$> TS.unmarshalNode node
+  matchers = fmap (fmap (TS.hoist Term)) TS.matchers
 
 instance Tags.ToTags Term where
   tags src = Tags.runTagging src . PyTags.tags . getTerm
diff --git a/semantic-python/src/Language/Python/Core.hs b/semantic-python/src/Language/Python/Core.hs
index 4ff75320c..291b4f0d6 100644
--- a/semantic-python/src/Language/Python/Core.hs
+++ b/semantic-python/src/Language/Python/Core.hs
@@ -49,6 +49,9 @@ newtype Bindings = Bindings { unBindings :: Stack Name }
 def :: Name -> Bindings -> Bindings
 def n = coerce (Stack.:> n)
 
+prelude :: Has Core sig t => [Name] -> t Name
+prelude = foldl' (\a b -> a ... b) (pure "__semantic_prelude")
+
 -- We leave the representation of Core syntax abstract so that it's not
 -- possible for us to 'cheat' by pattern-matching on or eliminating a
 -- compiled term.
@@ -199,8 +202,8 @@ instance Compile Py.ClassDefinition where
           bindings <- asks @Bindings (toList . unBindings)
           let buildName n = (n, pure n)
               contents = record . fmap buildName $ bindings
-              typefn = pure "__semantic_prelude" ... "type"
-              object = pure "__semantic_prelude" ... "object"
+              typefn = prelude ["type"]
+              object = prelude ["object"]
 
           pure (typefn $$ Core.string (coerce n) $$ object $$ contents)
 
@@ -346,11 +349,15 @@ instance Compile Py.Module where
 instance Compile Py.NamedExpression
 
 instance Compile Py.None where
-  -- None is not overridable, and thus always points to the prelude's None.
-  compile _it cc _ = cc (pure "__semantic_prelude" ... "None")
+  -- None is not an lvalue, and thus always points to the prelude's None.
+  compile _it cc _ = cc (prelude ["None"])
 
 instance Compile Py.NonlocalStatement
-instance Compile Py.NotOperator
+
+instance Compile Py.NotOperator where
+  compile _it@Py.NotOperator{ argument } cc next = do
+    val <- compile argument pure next
+    cc (prelude ["not"] $$ val)
 
 instance Compile Py.ParenthesizedExpression where
   compile it@Py.ParenthesizedExpression { extraChildren } cc
@@ -387,7 +394,7 @@ instance Compile Py.String where
 
     if any isNothing contents
       then pure . invariantViolated $ "Couldn't string-desugar " <> show it
-      else let new = pure "__semantic_prelude" ... "str" ... "__slots" ... "__new__"
+      else let new = prelude ["str", "__slots", "__new__"]
            in cc $ locate it (new $$ Core.string (mconcat (catMaybes contents)))
 
 instance Compile Py.Subscript
diff --git a/semantic-python/src/Prelude.score b/semantic-python/src/Prelude.score
index 775f96b3a..53130556e 100644
--- a/semantic-python/src/Prelude.score
+++ b/semantic-python/src/Prelude.score
@@ -10,6 +10,10 @@
 
   str <- type "str" object #record { __new__: \prim -> instance #unit prim #record{} };
 
+  // We will fill in the actual definition of these operators
+  // pending the presence of more eliminators.
+  not <- \val -> if val then #false else #true;
+
   NoneType <- type "None" object #record { __new__: \prim -> instance #unit prim #record{} };
   None <- NoneType.__slots.__new__ #unit;
 
@@ -19,6 +23,7 @@
   #record { type: type
           , object: object
           , str: str
+          , not: not
           , NoneType: NoneType
           , None: None
           , getitem: getitem}
diff --git a/semantic-python/test/fixtures/4-03-not-expression.py b/semantic-python/test/fixtures/4-03-not-expression.py
new file mode 100644
index 000000000..47c903f41
--- /dev/null
+++ b/semantic-python/test/fixtures/4-03-not-expression.py
@@ -0,0 +1,2 @@
+# CHECK-TREE: { x <- __semantic_prelude.not #true; #record { x: x }}
+x = not True
diff --git a/semantic-ruby/semantic-ruby.cabal b/semantic-ruby/semantic-ruby.cabal
index 7bd2dc6a4..60cb03403 100644
--- a/semantic-ruby/semantic-ruby.cabal
+++ b/semantic-ruby/semantic-ruby.cabal
@@ -28,8 +28,8 @@ common haskell
                      , semantic-source ^>= 0.0
                      , semantic-tags ^>= 0.0
                      , text ^>= 1.2.3
-                     , tree-sitter ^>= 0.7.2
-                     , tree-sitter-ruby ^>= 0.4
+                     , tree-sitter ^>= 0.8
+                     , tree-sitter-ruby ^>= 0.4.1
 
   ghc-options:
     -Weverything
diff --git a/semantic-ruby/src/Language/Ruby.hs b/semantic-ruby/src/Language/Ruby.hs
index 4895f0146..06c1b0dc8 100644
--- a/semantic-ruby/src/Language/Ruby.hs
+++ b/semantic-ruby/src/Language/Ruby.hs
@@ -6,10 +6,10 @@ module Language.Ruby
 , TreeSitter.Ruby.tree_sitter_ruby
 ) where
 
-
-import Control.Carrier.State.Strict
-import Data.Text (Text)
-import qualified Language.Ruby.Tags as PyTags
+import           Control.Carrier.State.Strict
+import           Data.Proxy
+import           Data.Text (Text)
+import qualified Language.Ruby.Tags as RbTags
 import qualified Tags.Tagging.Precise as Tags
 import qualified TreeSitter.Ruby (tree_sitter_ruby)
 import qualified TreeSitter.Ruby.AST as Rb
@@ -17,8 +17,12 @@ import qualified TreeSitter.Unmarshal as TS
 
 newtype Term a = Term { getTerm :: Rb.Program a }
 
+instance TS.SymbolMatching Term where
+  matchedSymbols _ = TS.matchedSymbols (Proxy :: Proxy Rb.Program)
+  showFailure _ = TS.showFailure (Proxy :: Proxy Rb.Program)
+
 instance TS.Unmarshal Term where
-  unmarshalNode node = Term <$> TS.unmarshalNode node
+  matchers = fmap (fmap (TS.hoist Term)) TS.matchers
 
 instance Tags.ToTags Term where
-  tags src = Tags.runTagging src . evalState @[Text] [] . PyTags.tags . getTerm
+  tags src = Tags.runTagging src . evalState @[Text] [] . RbTags.tags . getTerm
diff --git a/semantic-tsx/semantic-tsx.cabal b/semantic-tsx/semantic-tsx.cabal
index 021344d1e..c81b545d8 100644
--- a/semantic-tsx/semantic-tsx.cabal
+++ b/semantic-tsx/semantic-tsx.cabal
@@ -28,8 +28,8 @@ common haskell
                      , semantic-source ^>= 0.0
                      , semantic-tags ^>= 0.0
                      , text ^>= 1.2.3
-                     , tree-sitter ^>= 0.7.2
-                     , tree-sitter-tsx ^>= 0.4
+                     , tree-sitter ^>= 0.8
+                     , tree-sitter-tsx ^>= 0.4.1
 
   ghc-options:
     -Weverything
diff --git a/semantic-tsx/src/Language/TSX.hs b/semantic-tsx/src/Language/TSX.hs
index 909a22b81..2a439c54a 100644
--- a/semantic-tsx/src/Language/TSX.hs
+++ b/semantic-tsx/src/Language/TSX.hs
@@ -5,7 +5,7 @@ module Language.TSX
 , TreeSitter.TSX.tree_sitter_tsx
 ) where
 
-
+import           Data.Proxy
 import qualified Language.TSX.Tags as TsxTags
 import qualified Tags.Tagging.Precise as Tags
 import qualified TreeSitter.TSX (tree_sitter_tsx)
@@ -14,8 +14,12 @@ import qualified TreeSitter.Unmarshal as TS
 
 newtype Term a = Term { getTerm :: TSX.Program a }
 
+instance TS.SymbolMatching Term where
+  matchedSymbols _ = TS.matchedSymbols (Proxy :: Proxy TSX.Program)
+  showFailure _ = TS.showFailure (Proxy :: Proxy TSX.Program)
+
 instance TS.Unmarshal Term where
-  unmarshalNode node = Term <$> TS.unmarshalNode node
+  matchers = fmap (fmap (TS.hoist Term)) TS.matchers
 
 instance Tags.ToTags Term where
   tags src = Tags.runTagging src . TsxTags.tags . getTerm
diff --git a/semantic-typescript/semantic-typescript.cabal b/semantic-typescript/semantic-typescript.cabal
index 462a1ca32..0f0e8bed2 100644
--- a/semantic-typescript/semantic-typescript.cabal
+++ b/semantic-typescript/semantic-typescript.cabal
@@ -28,8 +28,8 @@ common haskell
                      , semantic-source ^>= 0.0
                      , semantic-tags ^>= 0.0
                      , text ^>= 1.2.3
-                     , tree-sitter ^>= 0.7.2
-                     , tree-sitter-typescript ^>= 0.4
+                     , tree-sitter ^>= 0.8
+                     , tree-sitter-typescript ^>= 0.4.1
 
   ghc-options:
     -Weverything
diff --git a/semantic-typescript/src/Language/TypeScript.hs b/semantic-typescript/src/Language/TypeScript.hs
index 6f946da99..13989839e 100644
--- a/semantic-typescript/src/Language/TypeScript.hs
+++ b/semantic-typescript/src/Language/TypeScript.hs
@@ -5,7 +5,7 @@ module Language.TypeScript
 , TreeSitter.TypeScript.tree_sitter_typescript
 ) where
 
-
+import           Data.Proxy
 import qualified Language.TypeScript.Tags as TsTags
 import qualified Tags.Tagging.Precise as Tags
 import qualified TreeSitter.TypeScript (tree_sitter_typescript)
@@ -14,8 +14,12 @@ import qualified TreeSitter.Unmarshal as TS
 
 newtype Term a = Term { getTerm :: TypeScript.Program a }
 
+instance TS.SymbolMatching Term where
+  matchedSymbols _ = TS.matchedSymbols (Proxy :: Proxy TypeScript.Program)
+  showFailure _ = TS.showFailure (Proxy :: Proxy TypeScript.Program)
+
 instance TS.Unmarshal Term where
-  unmarshalNode node = Term <$> TS.unmarshalNode node
+  matchers = fmap (fmap (TS.hoist Term)) TS.matchers
 
 instance Tags.ToTags Term where
   tags src = Tags.runTagging src . TsTags.tags . getTerm
diff --git a/semantic.cabal b/semantic.cabal
index f63de9cc0..9336f84ff 100644
--- a/semantic.cabal
+++ b/semantic.cabal
@@ -59,7 +59,7 @@ common dependencies
                      , fused-effects-exceptions ^>= 1
                      , fused-effects-resumable ^>= 0.1
                      , hashable >= 1.2.7 && < 1.4
-                     , tree-sitter ^>= 0.7.2
+                     , tree-sitter ^>= 0.8
                      , mtl ^>= 2.2.2
                      , network ^>= 2.8.0.0
                      , pathtype ^>= 0.8.1
@@ -303,12 +303,12 @@ library
                      , unliftio-core ^>= 0.1.2.0
                      , unordered-containers ^>= 0.2.9.0
                      , vector ^>= 0.12.0.2
-                     , tree-sitter-go ^>= 0.4
+                     , tree-sitter-go ^>= 0.4.1
                      , tree-sitter-php ^>= 0.2
-                     , tree-sitter-python ^>= 0.8
-                     , tree-sitter-ruby ^>= 0.4
-                     , tree-sitter-typescript ^>= 0.4
-                     , tree-sitter-tsx ^>= 0.4
+                     , tree-sitter-python ^>= 0.8.1
+                     , tree-sitter-ruby ^>= 0.4.1
+                     , tree-sitter-typescript ^>= 0.4.1
+                     , tree-sitter-tsx ^>= 0.4.1
 
 executable semantic
   import:              haskell, dependencies, executable-flags
@@ -358,7 +358,7 @@ test-suite test
                      , Generators
                      , Properties
   build-depends:       semantic
-                     , tree-sitter-json ^>= 0.5
+                     , tree-sitter-json ^>= 0.6
                      , Glob ^>= 0.10.0
                      , hedgehog ^>= 1
                      , hspec >= 2.6 && <3
@@ -388,16 +388,19 @@ test-suite parse-examples
                      , tasty
                      , tasty-hunit
 
-benchmark evaluation
+benchmark benchmarks
   import:              haskell, dependencies, executable-flags
   hs-source-dirs:      bench
   type:                exitcode-stdio-1.0
   main-is:             Main.hs
   other-modules:       Evaluation
+                     , Tagging
   ghc-options:         -static
   build-depends:       base
                      , algebraic-graphs
                      , gauge ^>= 0.2.5
+                     , Glob
+                     , lens >= 4.17 && < 4.19
                      , semantic
                      , semantic-source
 
diff --git a/src/Parsing/TreeSitter.hs b/src/Parsing/TreeSitter.hs
index 3590cde03..26c2dac3d 100644
--- a/src/Parsing/TreeSitter.hs
+++ b/src/Parsing/TreeSitter.hs
@@ -9,7 +9,6 @@ module Parsing.TreeSitter
 
 import Prologue
 
-import           Control.Carrier.Fail.Either
 import           Control.Carrier.Reader
 import qualified Control.Exception as Exc
 import           Foreign
@@ -58,8 +57,8 @@ parseToPreciseAST
   -> m (Either TSParseException (t Loc))
 parseToPreciseAST parseTimeout language blob = runParse parseTimeout language blob $ \ rootPtr ->
   TS.withCursor (castPtr rootPtr) $ \ cursor ->
-    runFail (runReader cursor (runReader (Source.bytes (blobSource blob)) (TS.peekNode >>= TS.unmarshalNode)))
-      >>= either (Exc.throw . UnmarshalFailure) pure
+    runReader (TS.UnmarshalState (Source.bytes (blobSource blob)) cursor) (liftIO (peek rootPtr) >>= TS.unmarshalNode)
+    `Exc.catch` (Exc.throw . UnmarshalFailure . TS.getUnmarshalError)
 
 instance Exception TSParseException where
   displayException = \case
@@ -102,8 +101,8 @@ anaM g = a where a = pure . embed <=< traverse a <=< g
 
 
 nodeRange :: TS.Node -> Range
-nodeRange TS.Node{..} = Range (fromIntegral nodeStartByte) (fromIntegral nodeEndByte)
+nodeRange node = Range (fromIntegral (TS.nodeStartByte node)) (fromIntegral (TS.nodeEndByte node))
 
 nodeSpan :: TS.Node -> Span
-nodeSpan TS.Node{..} = nodeStartPoint `seq` nodeEndPoint `seq` Span (pointPos nodeStartPoint) (pointPos nodeEndPoint)
+nodeSpan node = TS.nodeStartPoint node `seq` TS.nodeEndPoint node `seq` Span (pointPos (TS.nodeStartPoint node)) (pointPos (TS.nodeEndPoint node))
   where pointPos TS.TSPoint{..} = pointRow `seq` pointColumn `seq` Pos (1 + fromIntegral pointRow) (1 + fromIntegral pointColumn)
diff --git a/test/fixtures/json/corpus/hash.parseA.txt b/test/fixtures/json/corpus/hash.parseA.txt
index fa1d42fdd..a90d8b53b 100644
--- a/test/fixtures/json/corpus/hash.parseA.txt
+++ b/test/fixtures/json/corpus/hash.parseA.txt
@@ -7,22 +7,26 @@
             (Number "1")) 
           (String 
             [ 
-              (StringContent "a") ])) 
+              (StringContent 
+                []) ])) 
         (Pair 
           (Value 
             (Number "2")) 
           (String 
             [ 
-              (StringContent "b") ])) 
+              (StringContent 
+                []) ])) 
         (Pair 
           (Value 
             (Number "3")) 
           (String 
             [ 
-              (StringContent "c") ])) 
+              (StringContent 
+                []) ])) 
         (Pair 
           (Value 
             (Number "4")) 
           (String 
             [ 
-              (StringContent "d") ])) ])))
+              (StringContent 
+                []) ])) ])))
diff --git a/test/fixtures/json/corpus/hash.parseB.txt b/test/fixtures/json/corpus/hash.parseB.txt
index 84ab52762..a48142652 100644
--- a/test/fixtures/json/corpus/hash.parseB.txt
+++ b/test/fixtures/json/corpus/hash.parseB.txt
@@ -7,22 +7,26 @@
             (Number "2")) 
           (String 
             [ 
-              (StringContent "b") ])) 
+              (StringContent 
+                []) ])) 
         (Pair 
           (Value 
             (Number "3")) 
           (String 
             [ 
-              (StringContent "c'") ])) 
+              (StringContent 
+                []) ])) 
         (Pair 
           (Value 
             (Number "5")) 
           (String 
             [ 
-              (StringContent "d") ])) 
+              (StringContent 
+                []) ])) 
         (Pair 
           (Value 
             (Number "5")) 
           (String 
             [ 
-              (StringContent "e") ])) ])))
+              (StringContent 
+                []) ])) ])))
diff --git a/test/fixtures/json/corpus/string.parseA.txt b/test/fixtures/json/corpus/string.parseA.txt
index 79f422f8f..dd5d14f4c 100644
--- a/test/fixtures/json/corpus/string.parseA.txt
+++ b/test/fixtures/json/corpus/string.parseA.txt
@@ -5,4 +5,5 @@
         (Value 
           (String 
             [ 
-              (StringContent "hello") ])) ])))
+              (StringContent 
+                []) ])) ])))
diff --git a/test/fixtures/json/corpus/string.parseB.txt b/test/fixtures/json/corpus/string.parseB.txt
index 4198d7583..dd5d14f4c 100644
--- a/test/fixtures/json/corpus/string.parseB.txt
+++ b/test/fixtures/json/corpus/string.parseB.txt
@@ -5,4 +5,5 @@
         (Value 
           (String 
             [ 
-              (StringContent "world") ])) ])))
+              (StringContent 
+                []) ])) ])))