diff --git a/spec/sample-with-comments.js b/spec/sample-with-comments.js
deleted file mode 100644
index 66dc9051d..000000000
--- a/spec/sample-with-comments.js
+++ /dev/null
@@ -1 +0,0 @@
-undefined
\ No newline at end of file
diff --git a/spec/text-editor-registry-spec.js b/spec/text-editor-registry-spec.js
index 4f4d1ee93..4c6d680eb 100644
--- a/spec/text-editor-registry-spec.js
+++ b/spec/text-editor-registry-spec.js
@@ -1,6 +1,7 @@
 const TextEditorRegistry = require('../src/text-editor-registry')
 const TextEditor = require('../src/text-editor')
 const TextBuffer = require('text-buffer')
+const {Point, Range} = TextBuffer
 const {it, fit, ffit, fffit} = require('./async-spec-helpers')
 const dedent = require('dedent')
 
@@ -257,19 +258,19 @@ describe('TextEditorRegistry', function () {
 
     describe('when the "tabType" config setting is "auto"', function () {
       it('enables or disables soft tabs based on the editor\'s content', async function () {
+        await initialPackageActivation
         await atom.packages.activatePackage('language-javascript')
         atom.grammars.assignLanguageMode(editor, 'source.js')
         atom.config.set('editor.tabType', 'auto')
-
-        registry.maintainConfig(editor)
         await initialPackageActivation
+        const languageMode = editor.getBuffer().getLanguageMode()
 
         editor.setText(dedent`
           {
             hello;
           }
         `)
-        editor.getBuffer().getLanguageMode().retokenizeLines()
+        let disposable = registry.maintainConfig(editor)
         expect(editor.getSoftTabs()).toBe(true)
 
         editor.setText(dedent`
@@ -277,18 +278,17 @@ describe('TextEditorRegistry', function () {
           	hello;
           }
         `)
-        editor.getBuffer().getLanguageMode().retokenizeLines()
+        disposable.dispose()
+        disposable = registry.maintainConfig(editor)
         expect(editor.getSoftTabs()).toBe(false)
 
-        editor.setText(dedent`
+        editor.setTextInBufferRange(new Range(Point.ZERO, Point.ZERO), dedent`
           /*
            * Comment with a leading space.
            */
-          {
-          ${'\t'}hello;
-          }
-        ` + editor.getText())
-        editor.getBuffer().getLanguageMode().retokenizeLines()
+        ` + '\n')
+        disposable.dispose()
+        disposable = registry.maintainConfig(editor)
         expect(editor.getSoftTabs()).toBe(false)
 
         editor.setText(dedent`
@@ -300,8 +300,8 @@ describe('TextEditorRegistry', function () {
           	hello;
           }
         `)
-
-        editor.getBuffer().getLanguageMode().retokenizeLines()
+        disposable.dispose()
+        disposable = registry.maintainConfig(editor)
         expect(editor.getSoftTabs()).toBe(false)
 
         editor.setText(dedent`
@@ -313,7 +313,8 @@ describe('TextEditorRegistry', function () {
             hello;
           }
         `)
-        editor.getBuffer().getLanguageMode().retokenizeLines()
+        disposable.dispose()
+        disposable = registry.maintainConfig(editor)
         expect(editor.getSoftTabs()).toBe(true)
       })
     })
diff --git a/spec/tree-sitter-language-mode-spec.js b/spec/tree-sitter-language-mode-spec.js
index 01b053e35..58dae0241 100644
--- a/spec/tree-sitter-language-mode-spec.js
+++ b/spec/tree-sitter-language-mode-spec.js
@@ -39,7 +39,6 @@ describe('TreeSitterLanguageMode', () => {
 
       const languageMode = new TreeSitterLanguageMode({buffer, grammar})
       buffer.setLanguageMode(languageMode)
-      await nextHighlightingUpdate(languageMode)
 
       expectTokensToEqual(editor, [[
         {text: 'aa.', scopes: ['source']},
@@ -69,7 +68,6 @@ describe('TreeSitterLanguageMode', () => {
 
       const languageMode = new TreeSitterLanguageMode({buffer, grammar})
       buffer.setLanguageMode(languageMode)
-      await nextHighlightingUpdate(languageMode)
 
       expectTokensToEqual(editor, [[
         {text: 'a', scopes: ['source', 'variable']},
@@ -96,7 +94,6 @@ describe('TreeSitterLanguageMode', () => {
 
       const languageMode = new TreeSitterLanguageMode({buffer, grammar})
       buffer.setLanguageMode(languageMode)
-      await nextHighlightingUpdate(languageMode)
 
       expectTokensToEqual(editor, [
         [
@@ -124,7 +121,6 @@ describe('TreeSitterLanguageMode', () => {
 
       const languageMode = new TreeSitterLanguageMode({buffer, grammar})
       buffer.setLanguageMode(languageMode)
-      await nextHighlightingUpdate(languageMode)
 
       expect(
         languageMode.tree.rootNode.descendantForPosition(Point(1, 2), Point(1, 6)).toString()
@@ -169,7 +165,6 @@ describe('TreeSitterLanguageMode', () => {
 
       const languageMode = new TreeSitterLanguageMode({buffer, grammar})
       buffer.setLanguageMode(languageMode)
-      await nextHighlightingUpdate(languageMode)
 
       // missing closing paren
       expectTokensToEqual(editor, [
@@ -208,7 +203,6 @@ describe('TreeSitterLanguageMode', () => {
 
       const languageMode = new TreeSitterLanguageMode({buffer, grammar})
       buffer.setLanguageMode(languageMode)
-      await nextHighlightingUpdate(languageMode)
 
       expectTokensToEqual(editor, [
         [
@@ -241,7 +235,6 @@ describe('TreeSitterLanguageMode', () => {
       const languageMode = new TreeSitterLanguageMode({buffer, grammar})
       buffer.setLanguageMode(languageMode)
 
-      await nextHighlightingUpdate(languageMode)
       expectTokensToEqual(editor, [
         [{text: '// abc', scopes: ['comment']}],
         [{text: '', scopes: []}],
@@ -254,7 +247,6 @@ describe('TreeSitterLanguageMode', () => {
       ])
 
       buffer.insert([2, 0], '  ')
-      await nextHighlightingUpdate(languageMode)
       expectTokensToEqual(editor, [
         [{text: '// abc', scopes: ['comment']}],
         [{text: '', scopes: []}],
@@ -282,7 +274,6 @@ describe('TreeSitterLanguageMode', () => {
 
       const languageMode = new TreeSitterLanguageMode({buffer, grammar})
       buffer.setLanguageMode(languageMode)
-      await nextHighlightingUpdate(languageMode)
 
       expectTokensToEqual(editor, [
         [
@@ -324,7 +315,6 @@ describe('TreeSitterLanguageMode', () => {
 
       const languageMode = new TreeSitterLanguageMode({buffer, grammar})
       buffer.setLanguageMode(languageMode)
-      await nextHighlightingUpdate(languageMode)
 
       editor.foldBufferRange([[0, 2], [2, 0]])
 
@@ -361,7 +351,6 @@ describe('TreeSitterLanguageMode', () => {
 
       const languageMode = new TreeSitterLanguageMode({buffer, grammar})
       buffer.setLanguageMode(languageMode)
-      await nextHighlightingUpdate(languageMode)
 
       expectTokensToEqual(editor, [
         [
@@ -394,7 +383,6 @@ describe('TreeSitterLanguageMode', () => {
 
       const languageMode = new TreeSitterLanguageMode({buffer, grammar})
       buffer.setLanguageMode(languageMode)
-      await nextHighlightingUpdate(languageMode)
 
       expectTokensToEqual(editor, [
         [
@@ -422,7 +410,7 @@ describe('TreeSitterLanguageMode', () => {
 
         buffer.setText('abc;');
 
-        const languageMode = new TreeSitterLanguageMode({buffer, grammar})
+        const languageMode = new TreeSitterLanguageMode({buffer, grammar, syncOperationLimit: 0})
         buffer.setLanguageMode(languageMode)
         await nextHighlightingUpdate(languageMode)
         await new Promise(process.nextTick)
@@ -509,8 +497,6 @@ describe('TreeSitterLanguageMode', () => {
 
         const languageMode = new TreeSitterLanguageMode({buffer, grammar: jsGrammar, grammars: atom.grammars})
         buffer.setLanguageMode(languageMode)
-        await nextHighlightingUpdate(languageMode)
-        await nextHighlightingUpdate(languageMode)
 
         expectTokensToEqual(editor, [
           [
@@ -570,8 +556,6 @@ describe('TreeSitterLanguageMode', () => {
 
         const languageMode = new TreeSitterLanguageMode({buffer, grammar: htmlGrammar, grammars: atom.grammars})
         buffer.setLanguageMode(languageMode)
-        await nextHighlightingUpdate(languageMode)
-        await nextHighlightingUpdate(languageMode)
 
         expectTokensToEqual(editor, [
           [
@@ -608,7 +592,6 @@ describe('TreeSitterLanguageMode', () => {
         const languageMode = new TreeSitterLanguageMode({buffer, grammar: jsGrammar, grammars: atom.grammars})
         buffer.setLanguageMode(languageMode)
 
-        await nextHighlightingUpdate(languageMode)
         expectTokensToEqual(editor, [
           [
             {text: 'node.', scopes: []},
@@ -683,14 +666,13 @@ describe('TreeSitterLanguageMode', () => {
         atom.grammars.addGrammar(htmlGrammar)
 
         buffer.setText('<body>\n<script>\nb(<%= c.d %>)\n</script>\n</body>')
-        const languageMode = new TreeSitterLanguageMode({buffer, grammar: ejsGrammar, grammars: atom.grammars})
+        const languageMode = new TreeSitterLanguageMode({
+          buffer,
+          grammar: ejsGrammar,
+          grammars: atom.grammars,
+        })
         buffer.setLanguageMode(languageMode)
 
-        // Parse EJS, then HTML and template JS in parallel, then script tag JS
-        await nextHighlightingUpdate(languageMode)
-        await nextHighlightingUpdate(languageMode)
-        await nextHighlightingUpdate(languageMode)
-
         expectTokensToEqual(editor, [
           [
             {text: '<', scopes: ['html']},
@@ -752,7 +734,12 @@ describe('TreeSitterLanguageMode', () => {
         atom.grammars.addGrammar(htmlGrammar)
         buffer.setText('<script>\nhello();\n</script>')
 
-        const languageMode = new TreeSitterLanguageMode({buffer, grammar: htmlGrammar, grammars: atom.grammars})
+        const languageMode = new TreeSitterLanguageMode({
+          buffer,
+          grammar: htmlGrammar,
+          grammars: atom.grammars,
+          syncOperationLimit: 0
+        })
         buffer.setLanguageMode(languageMode)
 
         await promise
@@ -789,7 +776,6 @@ describe('TreeSitterLanguageMode', () => {
 
       const languageMode = new TreeSitterLanguageMode({buffer, grammar})
       buffer.setLanguageMode(languageMode)
-      await nextHighlightingUpdate(languageMode)
 
       expect(editor.isFoldableAtBufferRow(0)).toBe(false)
       expect(editor.isFoldableAtBufferRow(1)).toBe(true)
@@ -844,7 +830,6 @@ describe('TreeSitterLanguageMode', () => {
 
       const languageMode = new TreeSitterLanguageMode({buffer, grammar})
       buffer.setLanguageMode(languageMode)
-      await nextHighlightingUpdate(languageMode)
 
       // Avoid bringing the `else if...` up onto the same screen line as the preceding `if`.
       editor.foldBufferRow(1)
@@ -900,7 +885,6 @@ describe('TreeSitterLanguageMode', () => {
 
       const languageMode = new TreeSitterLanguageMode({buffer, grammar})
       buffer.setLanguageMode(languageMode)
-      await nextHighlightingUpdate(languageMode)
 
       expect(editor.isFoldableAtBufferRow(0)).toBe(true)
       expect(editor.isFoldableAtBufferRow(1)).toBe(false)
@@ -949,7 +933,6 @@ describe('TreeSitterLanguageMode', () => {
 
       const languageMode = new TreeSitterLanguageMode({buffer, grammar})
       buffer.setLanguageMode(languageMode)
-      await nextHighlightingUpdate(languageMode)
 
       expect(editor.isFoldableAtBufferRow(0)).toBe(true)
       expect(editor.isFoldableAtBufferRow(1)).toBe(false)
@@ -1024,7 +1007,6 @@ describe('TreeSitterLanguageMode', () => {
 
       const languageMode = new TreeSitterLanguageMode({buffer, grammar})
       buffer.setLanguageMode(languageMode)
-      await nextHighlightingUpdate(languageMode)
 
       editor.foldBufferRow(3)
       expect(getDisplayText(editor)).toBe(dedent `
@@ -1106,7 +1088,6 @@ describe('TreeSitterLanguageMode', () => {
 
       const languageMode = new TreeSitterLanguageMode({buffer, grammar})
       buffer.setLanguageMode(languageMode)
-      await nextHighlightingUpdate(languageMode)
 
       // Void elements have only one child
       expect(editor.isFoldableAtBufferRow(1)).toBe(false)
@@ -1159,7 +1140,6 @@ describe('TreeSitterLanguageMode', () => {
 
       const languageMode = new TreeSitterLanguageMode({buffer, grammar})
       buffer.setLanguageMode(languageMode)
-      await nextHighlightingUpdate(languageMode)
 
       expect(languageMode.tree.rootNode.toString()).toBe(
         "(program (if (identifier) " +
@@ -1229,7 +1209,6 @@ describe('TreeSitterLanguageMode', () => {
         `)
 
         buffer.setLanguageMode(new TreeSitterLanguageMode({buffer, grammar}))
-        await nextHighlightingUpdate(buffer.getLanguageMode())
 
         editor.foldBufferRow(0)
         expect(getDisplayText(editor)).toBe(dedent `
@@ -1289,9 +1268,6 @@ describe('TreeSitterLanguageMode', () => {
       const languageMode = new TreeSitterLanguageMode({buffer, grammar: jsGrammar, grammars: atom.grammars})
       buffer.setLanguageMode(languageMode)
 
-      await nextHighlightingUpdate(languageMode)
-      await nextHighlightingUpdate(languageMode)
-
       editor.foldBufferRow(2)
       expect(getDisplayText(editor)).toBe(
         `a = html \`
@@ -1334,7 +1310,6 @@ describe('TreeSitterLanguageMode', () => {
       buffer.setText('foo({bar: baz});')
 
       buffer.setLanguageMode(new TreeSitterLanguageMode({buffer, grammar}))
-      await nextHighlightingUpdate(buffer.getLanguageMode())
       expect(editor.scopeDescriptorForBufferPosition([0, 'foo({b'.length]).getScopesArray()).toEqual([
         'source.js',
         'property.name'
@@ -1385,9 +1360,6 @@ describe('TreeSitterLanguageMode', () => {
 
       const languageMode = new TreeSitterLanguageMode({buffer, grammar: htmlGrammar, grammars: atom.grammars})
       buffer.setLanguageMode(languageMode)
-      await nextHighlightingUpdate(languageMode)
-      await nextHighlightingUpdate(languageMode)
-      await nextHighlightingUpdate(languageMode)
 
       const position = buffer.findSync('name').start
       expect(languageMode.scopeDescriptorForPosition(position).getScopesArray()).toEqual([
@@ -1412,7 +1384,6 @@ describe('TreeSitterLanguageMode', () => {
         buffer.setText('foo({bar: baz});')
 
         buffer.setLanguageMode(new TreeSitterLanguageMode({buffer, grammar}))
-        await nextHighlightingUpdate(buffer.getLanguageMode())
         expect(editor.bufferRangeForScopeAtPosition(null, [0, 6])).toEqual(
           [[0, 5], [0, 8]]
         )
@@ -1453,9 +1424,6 @@ describe('TreeSitterLanguageMode', () => {
 
         const languageMode = new TreeSitterLanguageMode({buffer, grammar: htmlGrammar, grammars: atom.grammars})
         buffer.setLanguageMode(languageMode)
-        await nextHighlightingUpdate(languageMode)
-        await nextHighlightingUpdate(languageMode)
-        await nextHighlightingUpdate(languageMode)
 
         const nameProperty = buffer.findSync('name')
         const {start} = nameProperty
@@ -1475,7 +1443,6 @@ describe('TreeSitterLanguageMode', () => {
         buffer.setText('foo({bar: baz});')
 
         buffer.setLanguageMode(new TreeSitterLanguageMode({buffer, grammar}))
-        await nextHighlightingUpdate(buffer.getLanguageMode())
         expect(editor.bufferRangeForScopeAtPosition('.property_identifier', [0, 6])).toEqual(
           buffer.findSync('bar')
         )
@@ -1519,9 +1486,6 @@ describe('TreeSitterLanguageMode', () => {
 
         const languageMode = new TreeSitterLanguageMode({buffer, grammar: htmlGrammar, grammars: atom.grammars})
         buffer.setLanguageMode(languageMode)
-        await nextHighlightingUpdate(languageMode)
-        await nextHighlightingUpdate(languageMode)
-        await nextHighlightingUpdate(languageMode)
 
         const nameProperty = buffer.findSync('name')
         const {start} = nameProperty
@@ -1564,9 +1528,6 @@ describe('TreeSitterLanguageMode', () => {
 
         const languageMode = new TreeSitterLanguageMode({buffer, grammar: htmlGrammar, grammars: atom.grammars})
         buffer.setLanguageMode(languageMode)
-        await nextHighlightingUpdate(languageMode)
-        await nextHighlightingUpdate(languageMode)
-        await nextHighlightingUpdate(languageMode)
 
         const nameProperty = buffer.findSync('name')
         const {start} = nameProperty
@@ -1589,7 +1550,6 @@ describe('TreeSitterLanguageMode', () => {
       buffer.setText('foo(bar({x: 2}));')
       const languageMode = new TreeSitterLanguageMode({buffer, grammar})
       buffer.setLanguageMode(languageMode)
-      await nextHighlightingUpdate(languageMode)
       expect(languageMode.getSyntaxNodeAtPosition([0, 6]).range).toEqual(
         buffer.findSync('bar')
       )
@@ -1616,7 +1576,6 @@ describe('TreeSitterLanguageMode', () => {
       `)
 
       buffer.setLanguageMode(new TreeSitterLanguageMode({buffer, grammar}))
-      await nextHighlightingUpdate(buffer.getLanguageMode())
 
       editor.setCursorBufferPosition([1, 3])
       editor.selectLargerSyntaxNode()
@@ -1674,9 +1633,6 @@ describe('TreeSitterLanguageMode', () => {
       const languageMode = new TreeSitterLanguageMode({buffer, grammar: jsGrammar, grammars: atom.grammars})
       buffer.setLanguageMode(languageMode)
 
-      await nextHighlightingUpdate(languageMode)
-      await nextHighlightingUpdate(languageMode)
-
       editor.setCursorBufferPosition({row: 0, column: buffer.getText().indexOf('ef()')})
       editor.selectLargerSyntaxNode()
       expect(editor.getSelectedText()).toBe('def')
diff --git a/src/grammar-registry.js b/src/grammar-registry.js
index d82f14cb1..0c79d5b1e 100644
--- a/src/grammar-registry.js
+++ b/src/grammar-registry.js
@@ -134,7 +134,7 @@ class GrammarRegistry {
     }
 
     this.grammarScoresByBuffer.set(buffer, null)
-    if (grammar.scopeName !== buffer.getLanguageMode().getLanguageId()) {
+    if (grammar !== buffer.getLanguageMode().grammar) {
       buffer.setLanguageMode(this.languageModeForGrammarAndBuffer(grammar, buffer))
     }
 
@@ -161,7 +161,7 @@ class GrammarRegistry {
     )
     this.languageOverridesByBufferId.delete(buffer.id)
     this.grammarScoresByBuffer.set(buffer, result.score)
-    if (result.grammar.scopeName !== buffer.getLanguageMode().getLanguageId()) {
+    if (result.grammar !== buffer.getLanguageMode().grammar) {
       buffer.setLanguageMode(this.languageModeForGrammarAndBuffer(result.grammar, buffer))
     }
   }
diff --git a/src/text-editor-registry.js b/src/text-editor-registry.js
index 132b24ffb..e9dbf2f5c 100644
--- a/src/text-editor-registry.js
+++ b/src/text-editor-registry.js
@@ -218,7 +218,7 @@ class TextEditorRegistry {
   async updateAndMonitorEditorSettings (editor, oldLanguageMode) {
     await this.initialPackageActivationPromise
     this.updateEditorSettingsForLanguageMode(editor, oldLanguageMode)
-    await this.subscribeToSettingsForEditorScope(editor)
+    this.subscribeToSettingsForEditorScope(editor)
   }
 
   updateEditorSettingsForLanguageMode (editor, oldLanguageMode) {
@@ -246,7 +246,9 @@ class TextEditorRegistry {
     }
   }
 
-  async subscribeToSettingsForEditorScope (editor) {
+  subscribeToSettingsForEditorScope (editor) {
+    if (!this.editorsWithMaintainedConfig) return
+
     const scopeDescriptor = editor.getRootScopeDescriptor()
     const scopeChain = scopeDescriptor.getScopeChain()
 
diff --git a/src/text-editor.js b/src/text-editor.js
index ba063f7f0..3616db28c 100644
--- a/src/text-editor.js
+++ b/src/text-editor.js
@@ -4843,7 +4843,7 @@ class TextEditor {
 
     let endRow = bufferRow
     const rowCount = this.getLineCount()
-    while (endRow < rowCount) {
+    while (endRow + 1 < rowCount) {
       if (!NON_WHITESPACE_REGEXP.test(this.lineTextForBufferRow(endRow + 1))) break
       if (languageMode.isRowCommented(endRow + 1) !== isCommented) break
       endRow++
diff --git a/src/tree-sitter-language-mode.js b/src/tree-sitter-language-mode.js
index c046cf776..103b8816e 100644
--- a/src/tree-sitter-language-mode.js
+++ b/src/tree-sitter-language-mode.js
@@ -23,7 +23,7 @@ class TreeSitterLanguageMode {
     }
   }
 
-  constructor ({buffer, grammar, config, grammars}) {
+  constructor ({buffer, grammar, config, grammars, syncOperationLimit}) {
     TreeSitterLanguageMode._patchSyntaxNode()
     this.id = nextId++
     this.buffer = buffer
@@ -34,6 +34,10 @@ class TreeSitterLanguageMode {
     this.rootLanguageLayer = new LanguageLayer(this, grammar)
     this.injectionsMarkerLayer = buffer.addMarkerLayer()
 
+    if (syncOperationLimit != null) {
+      this.syncOperationLimit = syncOperationLimit
+    }
+
     this.rootScopeDescriptor = new ScopeDescriptor({scopes: [this.grammar.scopeName]})
     this.emitter = new Emitter()
     this.isFoldableCache = []
@@ -83,15 +87,23 @@ class TreeSitterLanguageMode {
     }
   }
 
-  async parse (language, oldTree, ranges) {
+  parse (language, oldTree, ranges) {
     const parser = PARSER_POOL.pop() || new Parser()
     parser.setLanguage(language)
-    const newTree = await parser.parseTextBuffer(this.buffer.buffer, oldTree, {
-      syncOperationLimit: 1000,
+    const result = parser.parseTextBuffer(this.buffer.buffer, oldTree, {
+      syncOperationLimit: this.syncOperationLimit,
       includedRanges: ranges
     })
-    PARSER_POOL.push(parser)
-    return newTree
+
+    if (result.then) {
+      return result.then(tree => {
+        PARSER_POOL.push(parser)
+        return tree
+      })
+    } else {
+      PARSER_POOL.push(parser)
+      return result
+    }
   }
 
   get tree () {
@@ -107,6 +119,7 @@ class TreeSitterLanguageMode {
   */
 
   buildHighlightIterator () {
+    if (!this.rootLanguageLayer) return new NullHighlightIterator()
     const layerIterators = [
       this.rootLanguageLayer.buildHighlightIterator(),
       ...this.injectionsMarkerLayer.getMarkers().map(m => m.languageLayer.buildHighlightIterator())
@@ -134,7 +147,15 @@ class TreeSitterLanguageMode {
     return this.grammar.commentStrings
   }
 
-  isRowCommented () {
+  isRowCommented (row) {
+    const firstNonWhitespaceRange = this.buffer.findInRangeSync(
+      /\S/,
+      new Range(new Point(row, 0), new Point(row, Infinity))
+    )
+    if (firstNonWhitespaceRange) {
+      const firstNode = this.getSyntaxNodeContainingRange(firstNonWhitespaceRange)
+      if (firstNode) return firstNode.type.includes('comment')
+    }
     return false
   }
 
@@ -265,7 +286,9 @@ class TreeSitterLanguageMode {
   }
 
   _forEachTreeWithRange (range, callback) {
-    callback(this.rootLanguageLayer.tree, this.rootLanguageLayer.grammar)
+    if (this.rootLanguageLayer.tree) {
+      callback(this.rootLanguageLayer.tree, this.rootLanguageLayer.grammar)
+    }
 
     const injectionMarkers = this.injectionsMarkerLayer.findMarkers({
       intersectsRange: range
@@ -523,11 +546,12 @@ class LanguageLayer {
     this.editedRange = null
 
     this.patchSinceCurrentParseStarted = new Patch()
-    const tree = await this.languageMode.parse(
+    let tree = this.languageMode.parse(
       this.grammar.languageModule,
       this.tree,
       includedRanges
     )
+    if (tree.then) tree = await tree
     tree.buffer = this.languageMode.buffer
 
     const changes = this.patchSinceCurrentParseStarted.getChanges()
@@ -1061,11 +1085,13 @@ function hasMatchingFoldSpec (specs, node) {
   'increaseIndentRegexForScopeDescriptor',
   'decreaseIndentRegexForScopeDescriptor',
   'decreaseNextIndentRegexForScopeDescriptor',
-  'regexForPattern'
+  'regexForPattern',
+  'getNonWordCharacters'
 ].forEach(methodName => {
   TreeSitterLanguageMode.prototype[methodName] = TextMateLanguageMode.prototype[methodName]
 })
 
 TreeSitterLanguageMode.LanguageLayer = LanguageLayer
+TreeSitterLanguageMode.prototype.syncOperationLimit = 1000
 
 module.exports = TreeSitterLanguageMode