deps: add acorn stage-3 plugins

This adds bigint, class-fields, numeric-separators, static-class
features, private class methods and fields as dependency. That way
it's possible to use these in combination with acorn to parse these
language features.

This also removes a couple of files that were not necessary for
Node.js to reduce the code base.

PR-URL: https://github.com/nodejs/node/pull/27400
Refs: https://github.com/nodejs/node/issues/27391
Refs: https://github.com/nodejs/node/issues/25835
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Michaël Zasso <targos@protonmail.com>

30 files changed, 1180 insertions, 0 deletions

diff --git a/deps/acorn-plugins/acorn-bigint/CHANGELOG.md b/deps/acorn-plugins/acorn-bigint/CHANGELOG.md
new file mode 100644
index 0000000000..1d12d708f2
--- /dev/null
+++ b/deps/acorn-plugins/acorn-bigint/CHANGELOG.md
@@ -0,0 +1,21 @@
+## 0.4.0 (2019-04-04)
+
+* Make compatible with acorn-numeric-separator
+
+## 0.3.1 (2018-10-06)
+
+* Fix creation of BigInt values everywhere (Thanks, Gus Caplan!)
+
+## 0.3.0 (2018-09-14)
+
+* Update to new acorn 6 interface
+* Actually support creating BigInt values in AST in Chrome
+* Change license to MIT
+
+## 0.2.0 (2017-12-20)
+
+* Emit BigInt values in AST if supported by runtime engine
+
+## 0.1.0 (2017-12-19)
+
+Initial release
diff --git a/deps/acorn-plugins/acorn-bigint/LICENSE b/deps/acorn-plugins/acorn-bigint/LICENSE
new file mode 100644
index 0000000000..7c2b27a19c
--- /dev/null
+++ b/deps/acorn-plugins/acorn-bigint/LICENSE
@@ -0,0 +1,19 @@
+Copyright (C) 2017-2018 by Adrian Heine
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/deps/acorn-plugins/acorn-bigint/README.md b/deps/acorn-plugins/acorn-bigint/README.md
new file mode 100644
index 0000000000..b0b6bb5554
--- /dev/null
+++ b/deps/acorn-plugins/acorn-bigint/README.md
@@ -0,0 +1,21 @@
+# BigInt support for Acorn
+
+[![NPM version](https://img.shields.io/npm/v/acorn-bigint.svg)](https://www.npmjs.org/package/acorn-bigint)
+
+This is a plugin for [Acorn](http://marijnhaverbeke.nl/acorn/) - a tiny, fast JavaScript parser, written completely in JavaScript.
+
+It implements support for arbitrary precision integers as defined in the stage 3 proposal [BigInt: Arbitrary precision integers in JavaScript](https://github.com/tc39/proposal-bigint). The emitted AST follows [an ESTree proposal](https://github.com/estree/estree/blob/132be9b9ec376adbc082dd5f6ba78aefd7a1a864/experimental/bigint.md).
+
+## Usage
+
+This module provides a plugin that can be used to extend the Acorn `Parser` class:
+
+```javascript
+const {Parser} = require('acorn');
+const bigInt = require('acorn-bigint');
+Parser.extend(bigInt).parse('100n');
+```
+
+## License
+
+This plugin is released under an [MIT License](./LICENSE).
diff --git a/deps/acorn-plugins/acorn-bigint/index.js b/deps/acorn-plugins/acorn-bigint/index.js
new file mode 100644
index 0000000000..8e63515e11
--- /dev/null
+++ b/deps/acorn-plugins/acorn-bigint/index.js
@@ -0,0 +1,59 @@
+"use strict"
+
+const acorn = require('internal/deps/acorn/acorn/dist/acorn')
+const tt = acorn.tokTypes
+const isIdentifierStart = acorn.isIdentifierStart
+
+module.exports = function(Parser) {
+  return class extends Parser {
+    parseLiteral(value) {
+      const node = super.parseLiteral(value)
+      if (node.raw.charCodeAt(node.raw.length - 1) == 110) node.bigint = this.getNumberInput(node.start, node.end)
+      return node
+    }
+
+    readRadixNumber(radix) {
+      let start = this.pos
+      this.pos += 2 // 0x
+      let val = this.readInt(radix)
+      if (val === null) this.raise(this.start + 2, `Expected number in radix ${radix}`)
+      if (this.input.charCodeAt(this.pos) == 110) {
+        let str = this.getNumberInput(start, this.pos)
+        val = typeof BigInt !== "undefined" ? BigInt(str) : null
+        ++this.pos
+      } else if (isIdentifierStart(this.fullCharCodeAtPos())) this.raise(this.pos, "Identifier directly after number")
+      return this.finishToken(tt.num, val)
+    }
+
+    readNumber(startsWithDot) {
+      let start = this.pos
+
+      // Not an int
+      if (startsWithDot) return super.readNumber(startsWithDot)
+
+      // Legacy octal
+      if (this.input.charCodeAt(start) === 48 && this.input.charCodeAt(start + 1) !== 110) {
+        return super.readNumber(startsWithDot)
+      }
+
+      if (this.readInt(10) === null) this.raise(start, "Invalid number")
+
+      // Not a BigInt, reset and parse again
+      if (this.input.charCodeAt(this.pos) != 110) {
+        this.pos = start
+        return super.readNumber(startsWithDot)
+      }
+
+      let str = this.getNumberInput(start, this.pos)
+      let val = typeof BigInt !== "undefined" ? BigInt(str) : null
+      ++this.pos
+      return this.finishToken(tt.num, val)
+    }
+
+    // This is basically a hook for acorn-numeric-separator
+    getNumberInput(start, end) {
+      if (super.getNumberInput) return super.getNumberInput(start, end)
+      return this.input.slice(start, end)
+    }
+  }
+}
diff --git a/deps/acorn-plugins/acorn-bigint/package.json b/deps/acorn-plugins/acorn-bigint/package.json
new file mode 100644
index 0000000000..073cdfb86c
--- /dev/null
+++ b/deps/acorn-plugins/acorn-bigint/package.json
@@ -0,0 +1,65 @@
+{
+  "_from": "acorn-bigint",
+  "_id": "acorn-bigint@0.4.0",
+  "_inBundle": false,
+  "_integrity": "sha512-W9iaqWzqFo7ZBLmI9dMjHYGrN0Nm/ZgToqhvd3RELJux7RsX6k1/80h+bD9TtTpeKky/kYNbr3+vHWqI3hdyfA==",
+  "_location": "/acorn-bigint",
+  "_phantomChildren": {},
+  "_requested": {
+    "type": "tag",
+    "registry": true,
+    "raw": "acorn-bigint",
+    "name": "acorn-bigint",
+    "escapedName": "acorn-bigint",
+    "rawSpec": "",
+    "saveSpec": null,
+    "fetchSpec": "latest"
+  },
+  "_requiredBy": [
+    "#USER",
+    "/"
+  ],
+  "_resolved": "https://registry.npmjs.org/acorn-bigint/-/acorn-bigint-0.4.0.tgz",
+  "_shasum": "af3245ed8a7c3747387fca4680ae1960f617c4cd",
+  "_spec": "acorn-bigint",
+  "_where": "/home/ruben/repos/node/node",
+  "bugs": {
+    "url": "https://github.com/acornjs/acorn-bigint/issues"
+  },
+  "bundleDependencies": false,
+  "contributors": [
+    {
+      "name": "Adrian Heine",
+      "email": "mail@adrianheine.de"
+    }
+  ],
+  "deprecated": false,
+  "description": "Support for BigInt in acorn",
+  "devDependencies": {
+    "acorn": "^6.1.1",
+    "eslint": "^5.16.0",
+    "eslint-plugin-node": "^8.0.1",
+    "mocha": "^6.0.2",
+    "test262": "git+https://github.com/tc39/test262.git#611919174ffe060503691a0c7e3eb2a65b646124",
+    "test262-parser-runner": "^0.5.0"
+  },
+  "engines": {
+    "node": ">=4.8.2"
+  },
+  "homepage": "https://github.com/acornjs/acorn-bigint",
+  "license": "MIT",
+  "name": "acorn-bigint",
+  "peerDependencies": {
+    "acorn": "^6.0.0"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/acornjs/acorn-bigint.git"
+  },
+  "scripts": {
+    "lint": "eslint -c .eslintrc.json .",
+    "test": "mocha",
+    "test:test262": "node run_test262.js"
+  },
+  "version": "0.4.0"
+}
diff --git a/deps/acorn-plugins/acorn-class-fields/CHANGELOG.md b/deps/acorn-plugins/acorn-class-fields/CHANGELOG.md
new file mode 100644
index 0000000000..de2c66b0c3
--- /dev/null
+++ b/deps/acorn-plugins/acorn-class-fields/CHANGELOG.md
@@ -0,0 +1,28 @@
+## 0.3.1 (2019-02-09)
+
+* Restore compatibility with acorn-private-methods
+
+## 0.3.0 (2019-02-09)
+
+* Require acorn >= 6.1.0
+
+## 0.2.1 (2018-11-06)
+
+* Adapt to changes in acorn 6.0.3
+
+## 0.2.0 (2018-09-14)
+
+* Update to new acorn 6 interface
+* Change license to MIT
+
+## 0.1.2 (2018-01-26)
+
+* Don't accept whitespace between hash and private name
+
+## 0.1.1 (2018-01-17)
+
+* Correctly parse all fields named `async`
+
+## 0.1.0 (2018-01-13)
+
+Initial release
diff --git a/deps/acorn-plugins/acorn-class-fields/LICENSE b/deps/acorn-plugins/acorn-class-fields/LICENSE
new file mode 100644
index 0000000000..7c2b27a19c
--- /dev/null
+++ b/deps/acorn-plugins/acorn-class-fields/LICENSE
@@ -0,0 +1,19 @@
+Copyright (C) 2017-2018 by Adrian Heine
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/deps/acorn-plugins/acorn-class-fields/README.md b/deps/acorn-plugins/acorn-class-fields/README.md
new file mode 100644
index 0000000000..60f3463e94
--- /dev/null
+++ b/deps/acorn-plugins/acorn-class-fields/README.md
@@ -0,0 +1,21 @@
+# Class fields support for Acorn
+
+[![NPM version](https://img.shields.io/npm/v/acorn-class-fields.svg)](https://www.npmjs.org/package/acorn-class-fields)
+
+This is a plugin for [Acorn](http://marijnhaverbeke.nl/acorn/) - a tiny, fast JavaScript parser, written completely in JavaScript.
+
+It implements support for class fields as defined in the stage 3 proposal [Class field declarations for JavaScript](https://github.com/tc39/proposal-class-fields). The emitted AST follows [an ESTree proposal](https://github.com/estree/estree/pull/180).
+
+## Usage
+
+This module provides a plugin that can be used to extend the Acorn `Parser` class:
+
+```javascript
+const {Parser} = require('acorn');
+const classFields = require('acorn-class-fields');
+Parser.extend(classFields).parse('class X { x = 0 }');
+```
+
+## License
+
+This plugin is released under an [MIT License](./LICENSE).
diff --git a/deps/acorn-plugins/acorn-class-fields/index.js b/deps/acorn-plugins/acorn-class-fields/index.js
new file mode 100644
index 0000000000..20348c80c6
--- /dev/null
+++ b/deps/acorn-plugins/acorn-class-fields/index.js
@@ -0,0 +1,59 @@
+"use strict"
+
+const acorn = require('internal/deps/acorn/acorn/dist/acorn')
+const tt = acorn.tokTypes
+const privateClassElements = require('internal/deps/acorn-plugins/acorn-private-class-elements/index')
+
+function maybeParseFieldValue(field) {
+  if (this.eat(tt.eq)) {
+    const oldInFieldValue = this._inFieldValue
+    this._inFieldValue = true
+    field.value = this.parseExpression()
+    this._inFieldValue = oldInFieldValue
+  } else field.value = null
+}
+
+module.exports = function(Parser) {
+  Parser = privateClassElements(Parser)
+  return class extends Parser {
+    // Parse fields
+    parseClassElement(_constructorAllowsSuper) {
+      if (this.options.ecmaVersion >= 8 && (this.type == tt.name || this.type == this.privateNameToken || this.type == tt.bracketL || this.type == tt.string)) {
+        const branch = this._branch()
+        if (branch.type == tt.bracketL) {
+          let count = 0
+          do {
+            if (branch.eat(tt.bracketL)) ++count
+            else if (branch.eat(tt.bracketR)) --count
+            else branch.next()
+          } while (count > 0)
+        } else branch.next()
+        if (branch.type == tt.eq || branch.canInsertSemicolon() || branch.type == tt.semi) {
+          const node = this.startNode()
+          if (this.type == this.privateNameToken) {
+            this.parsePrivateClassElementName(node)
+          } else {
+            this.parsePropertyName(node)
+          }
+          if ((node.key.type === "Identifier" && node.key.name === "constructor") ||
+              (node.key.type === "Literal" && node.key.value === "constructor")) {
+            this.raise(node.key.start, "Classes may not have a field called constructor")
+          }
+          maybeParseFieldValue.call(this, node)
+          this.finishNode(node, "FieldDefinition")
+          this.semicolon()
+          return node
+        }
+      }
+
+      return super.parseClassElement.apply(this, arguments)
+    }
+
+    // Prohibit arguments in class field initializers
+    parseIdent(liberal, isBinding) {
+      const ident = super.parseIdent(liberal, isBinding)
+      if (this._inFieldValue && ident.name == "arguments") this.raise(ident.start, "A class field initializer may not contain arguments")
+      return ident
+    }
+  }
+}
diff --git a/deps/acorn-plugins/acorn-class-fields/package.json b/deps/acorn-plugins/acorn-class-fields/package.json
new file mode 100644
index 0000000000..4df166ba19
--- /dev/null
+++ b/deps/acorn-plugins/acorn-class-fields/package.json
@@ -0,0 +1,68 @@
+{
+  "_from": "acorn-class-fields",
+  "_id": "acorn-class-fields@0.3.1",
+  "_inBundle": false,
+  "_integrity": "sha512-X/8hSJuregAnrvfV1Y80VJNfeJx1uhw7yskOwvL631ygYeCGVLPumCnnPDHYZ8acV3ytHhg53K171H3tAemgiw==",
+  "_location": "/acorn-class-fields",
+  "_phantomChildren": {},
+  "_requested": {
+    "type": "tag",
+    "registry": true,
+    "raw": "acorn-class-fields",
+    "name": "acorn-class-fields",
+    "escapedName": "acorn-class-fields",
+    "rawSpec": "",
+    "saveSpec": null,
+    "fetchSpec": "latest"
+  },
+  "_requiredBy": [
+    "#USER",
+    "/"
+  ],
+  "_resolved": "https://registry.npmjs.org/acorn-class-fields/-/acorn-class-fields-0.3.1.tgz",
+  "_shasum": "032ce47a9688a71d4713ee366fadcb7fefaea9e0",
+  "_spec": "acorn-class-fields",
+  "_where": "/home/ruben/repos/node/node",
+  "bugs": {
+    "url": "https://github.com/acornjs/acorn-class-fields/issues"
+  },
+  "bundleDependencies": false,
+  "contributors": [
+    {
+      "name": "Adrian Heine",
+      "email": "mail@adrianheine.de"
+    }
+  ],
+  "dependencies": {
+    "acorn-private-class-elements": "^0.1.1"
+  },
+  "deprecated": false,
+  "description": "Support for class fields in acorn",
+  "devDependencies": {
+    "acorn": "^6.1.0",
+    "eslint": "^5.13.0",
+    "eslint-plugin-node": "^8.0.1",
+    "mocha": "^5.2.0",
+    "test262": "git+https://github.com/tc39/test262.git#33a306d1026b72227eb50a918db19ada16f12b3d",
+    "test262-parser-runner": "^0.5.0"
+  },
+  "engines": {
+    "node": ">=4.8.2"
+  },
+  "homepage": "https://github.com/acornjs/acorn-class-fields",
+  "license": "MIT",
+  "name": "acorn-class-fields",
+  "peerDependencies": {
+    "acorn": "^6.0.0"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/acornjs/acorn-class-fields.git"
+  },
+  "scripts": {
+    "lint": "eslint -c .eslintrc.json .",
+    "test": "mocha",
+    "test:test262": "node run_test262.js"
+  },
+  "version": "0.3.1"
+}
diff --git a/deps/acorn-plugins/acorn-numeric-separator/CHANGELOG.md b/deps/acorn-plugins/acorn-numeric-separator/CHANGELOG.md
new file mode 100644
index 0000000000..dfe8e3ea9d
--- /dev/null
+++ b/deps/acorn-plugins/acorn-numeric-separator/CHANGELOG.md
@@ -0,0 +1,16 @@
+## 0.3.0 (2019-04-04)
+
+* Make compatible with acorn-bigint
+
+## 0.2.0 (2018-09-14)
+
+* Update to new acorn 6 interface
+* Change license to MIT
+
+## 0.1.1 (2018-01-16)
+
+* Don't bail on empty integers as in `1.`
+
+## 0.1.0 (2017-12-19)
+
+Initial release
diff --git a/deps/acorn-plugins/acorn-numeric-separator/LICENSE b/deps/acorn-plugins/acorn-numeric-separator/LICENSE
new file mode 100644
index 0000000000..7c2b27a19c
--- /dev/null
+++ b/deps/acorn-plugins/acorn-numeric-separator/LICENSE
@@ -0,0 +1,19 @@
+Copyright (C) 2017-2018 by Adrian Heine
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/deps/acorn-plugins/acorn-numeric-separator/README.md b/deps/acorn-plugins/acorn-numeric-separator/README.md
new file mode 100644
index 0000000000..27188572d1
--- /dev/null
+++ b/deps/acorn-plugins/acorn-numeric-separator/README.md
@@ -0,0 +1,21 @@
+# Numeric separator support for Acorn
+
+[![NPM version](https://img.shields.io/npm/v/acorn-numeric-separator.svg)](https://www.npmjs.org/package/acorn-numeric-separator)
+
+This is a plugin for [Acorn](http://marijnhaverbeke.nl/acorn/) - a tiny, fast JavaScript parser, written completely in JavaScript.
+
+It implements support for numeric separators as defined in the stage 3 proposal [Numeric Separators](https://github.com/tc39/proposal-numeric-separator).
+
+## Usage
+
+This module provides a plugin that can be used to extend the Acorn `Parser` class to parse numeric separators:
+
+```javascript
+var acorn = require('acorn');
+var numericSeparator = require('acorn-numeric-separator');
+acorn.Parser.extend(numericSeparator).parse('100_000');
+```
+
+## License
+
+This plugin is released under an [MIT License](./LICENSE).
diff --git a/deps/acorn-plugins/acorn-numeric-separator/index.js b/deps/acorn-plugins/acorn-numeric-separator/index.js
new file mode 100644
index 0000000000..52f207cfd8
--- /dev/null
+++ b/deps/acorn-plugins/acorn-numeric-separator/index.js
@@ -0,0 +1,49 @@
+"use strict"
+
+module.exports = function(Parser) {
+  return class extends Parser {
+    readInt(radix, len) {
+      // Hack: len is only != null for unicode escape sequences,
+      // where numeric separators are not allowed
+      if (len != null) return super.readInt(radix, len)
+
+      let start = this.pos, total = 0, acceptUnderscore = false
+      for (;;) {
+        let code = this.input.charCodeAt(this.pos), val
+        if (code >= 97) val = code - 97 + 10 // a
+        else if (code == 95) {
+          if (!acceptUnderscore) this.raise(this.pos, "Invalid numeric separator")
+          ++this.pos
+          acceptUnderscore = false
+          continue
+        } else if (code >= 65) val = code - 65 + 10 // A
+        else if (code >= 48 && code <= 57) val = code - 48 // 0-9
+        else val = Infinity
+        if (val >= radix) break
+        ++this.pos
+        total = total * radix + val
+        acceptUnderscore = true
+      }
+      if (this.pos === start) return null
+      if (!acceptUnderscore) this.raise(this.pos - 1, "Invalid numeric separator")
+
+      return total
+    }
+
+    readNumber(startsWithDot) {
+      const token = super.readNumber(startsWithDot)
+      let octal = this.end - this.start >= 2 && this.input.charCodeAt(this.start) === 48
+      const stripped = this.getNumberInput(this.start, this.end)
+      if (stripped.length < this.end - this.start) {
+        if (octal) this.raise(this.start, "Invalid number")
+        this.value = parseFloat(stripped)
+      }
+      return token
+    }
+
+    // This is used by acorn-bigint
+    getNumberInput(start, end) {
+      return this.input.slice(start, end).replace(/_/g, "")
+    }
+  }
+}
diff --git a/deps/acorn-plugins/acorn-numeric-separator/package.json b/deps/acorn-plugins/acorn-numeric-separator/package.json
new file mode 100644
index 0000000000..bf3615e6b7
--- /dev/null
+++ b/deps/acorn-plugins/acorn-numeric-separator/package.json
@@ -0,0 +1,65 @@
+{
+  "_from": "acorn-numeric-separator",
+  "_id": "acorn-numeric-separator@0.3.0",
+  "_inBundle": false,
+  "_integrity": "sha512-g9FikQZHwG/P1Xs+dDzecqagmGBbU4b8OF4UbDQK8Wr8apwuFGG1c7KiaFxC4ClYU8D7zNl60vzqOCUuhKM3kA==",
+  "_location": "/acorn-numeric-separator",
+  "_phantomChildren": {},
+  "_requested": {
+    "type": "tag",
+    "registry": true,
+    "raw": "acorn-numeric-separator",
+    "name": "acorn-numeric-separator",
+    "escapedName": "acorn-numeric-separator",
+    "rawSpec": "",
+    "saveSpec": null,
+    "fetchSpec": "latest"
+  },
+  "_requiredBy": [
+    "#USER",
+    "/"
+  ],
+  "_resolved": "https://registry.npmjs.org/acorn-numeric-separator/-/acorn-numeric-separator-0.3.0.tgz",
+  "_shasum": "15e2f9a698bbec83a339a70a7026ab1d9d257de2",
+  "_spec": "acorn-numeric-separator",
+  "_where": "/home/ruben/repos/node/node",
+  "bugs": {
+    "url": "https://github.com/acornjs/acorn-numeric-separator/issues"
+  },
+  "bundleDependencies": false,
+  "contributors": [
+    {
+      "name": "Adrian Heine",
+      "email": "mail@adrianheine.de"
+    }
+  ],
+  "deprecated": false,
+  "description": "Support for numeric separators in acorn",
+  "devDependencies": {
+    "acorn": "^6.0.0",
+    "eslint": "^5.5.0",
+    "eslint-plugin-node": "^8.0.1",
+    "mocha": "^6.0.2",
+    "test262": "git+https://github.com/tc39/test262.git#de567d3aa5de4eaa11e00131d26b9fe77997dfb0",
+    "test262-parser-runner": "^0.5.0"
+  },
+  "engines": {
+    "node": ">=4.8.2"
+  },
+  "homepage": "https://github.com/acornjs/acorn-numeric-separator",
+  "license": "MIT",
+  "name": "acorn-numeric-separator",
+  "peerDependencies": {
+    "acorn": "^6.0.0"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/acornjs/acorn-numeric-separator.git"
+  },
+  "scripts": {
+    "lint": "eslint -c .eslintrc.json .",
+    "test": "mocha",
+    "test:test262": "node run_test262.js"
+  },
+  "version": "0.3.0"
+}
diff --git a/deps/acorn-plugins/acorn-private-class-elements/CHANGELOG.md b/deps/acorn-plugins/acorn-private-class-elements/CHANGELOG.md
new file mode 100644
index 0000000000..5b49344b7a
--- /dev/null
+++ b/deps/acorn-plugins/acorn-private-class-elements/CHANGELOG.md
@@ -0,0 +1,7 @@
+## 0.1.1 (2019-02-09)
+
+* Add \_branch() method
+
+## 0.1.0 (2019-02-09)
+
+Initial release
diff --git a/deps/acorn-plugins/acorn-private-class-elements/LICENSE b/deps/acorn-plugins/acorn-private-class-elements/LICENSE
new file mode 100644
index 0000000000..7c2b27a19c
--- /dev/null
+++ b/deps/acorn-plugins/acorn-private-class-elements/LICENSE
@@ -0,0 +1,19 @@
+Copyright (C) 2017-2018 by Adrian Heine
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/deps/acorn-plugins/acorn-private-class-elements/README.md b/deps/acorn-plugins/acorn-private-class-elements/README.md
new file mode 100644
index 0000000000..0d228820cd
--- /dev/null
+++ b/deps/acorn-plugins/acorn-private-class-elements/README.md
@@ -0,0 +1,11 @@
+# Helpers for supporting private class methods and fields for Acorn
+
+[![NPM version](https://img.shields.io/npm/v/acorn-private-class-elements.svg)](https://www.npmjs.org/package/acorn-private-class-elements)
+
+This is a plugin for [Acorn](http://marijnhaverbeke.nl/acorn/) - a tiny, fast JavaScript parser, written completely in JavaScript.
+
+It provides helpers for implementing support for private class elements. The emitted AST follows [an ESTree proposal](https://github.com/estree/estree/pull/180).
+
+## License
+
+This plugin is released under an [MIT License](./LICENSE).
diff --git a/deps/acorn-plugins/acorn-private-class-elements/index.js b/deps/acorn-plugins/acorn-private-class-elements/index.js
new file mode 100644
index 0000000000..90f2b70437
--- /dev/null
+++ b/deps/acorn-plugins/acorn-private-class-elements/index.js
@@ -0,0 +1,123 @@
+"use strict"
+
+const acorn = require('internal/deps/acorn/acorn/dist/acorn')
+if (acorn.version.indexOf("6.") != 0 || acorn.version.indexOf("6.0.") == 0) {
+  throw new Error(`acorn-private-class-elements requires acorn@^6.1.0, not ${acorn.version}`)
+}
+const tt = acorn.tokTypes
+const TokenType = acorn.TokenType
+
+module.exports = function(Parser) {
+  // Only load this plugin once.
+  if (Parser.prototype.parsePrivateName) {
+    return Parser
+  }
+
+  // Make sure `Parser` comes from the same acorn as our `tt`,
+  // otherwise the comparisons fail.
+  let cur = Parser
+  while (cur && cur !== acorn.Parser) {
+    cur = cur.__proto__
+  }
+  if (cur !== acorn.Parser) {
+    throw new Error("acorn-private-class-elements does not support mixing different acorn copies")
+  }
+
+  Parser = class extends Parser {
+    _branch() {
+      this.__branch = this.__branch || new Parser({ecmaVersion: this.options.ecmaVersion}, this.input)
+      this.__branch.end = this.end
+      this.__branch.pos = this.pos
+      this.__branch.type = this.type
+      this.__branch.value = this.value
+      this.__branch.containsEsc = this.containsEsc
+      return this.__branch
+    }
+
+    parsePrivateClassElementName(element) {
+      element.computed = false
+      element.key = this.parsePrivateName()
+      if (element.key.name == "constructor") this.raise(element.key.start, "Classes may not have a private element named constructor")
+      const accept = {get: "set", set: "get"}[element.kind]
+      const privateBoundNames = this._privateBoundNamesStack[this._privateBoundNamesStack.length - 1]
+      if (Object.prototype.hasOwnProperty.call(privateBoundNames, element.key.name) && privateBoundNames[element.key.name] !== accept) {
+        this.raise(element.start, "Duplicate private element")
+      }
+      privateBoundNames[element.key.name] = element.kind || true
+      delete this._unresolvedPrivateNamesStack[this._unresolvedPrivateNamesStack.length - 1][element.key.name]
+      return element.key
+    }
+
+    parsePrivateName() {
+      const node = this.startNode()
+      node.name = this.value
+      this.next()
+      this.finishNode(node, "PrivateName")
+      if (this.options.allowReserved == "never") this.checkUnreserved(node)
+      return node
+    }
+
+    // Parse # token
+    getTokenFromCode(code) {
+      if (code === 35) {
+        ++this.pos
+        const word = this.readWord1()
+        return this.finishToken(this.privateNameToken, word)
+      }
+      return super.getTokenFromCode(code)
+    }
+
+    // Manage stacks and check for undeclared private names
+    parseClass(node, isStatement) {
+      this._privateBoundNamesStack = this._privateBoundNamesStack || []
+      const privateBoundNames = Object.create(this._privateBoundNamesStack[this._privateBoundNamesStack.length - 1] || null)
+      this._privateBoundNamesStack.push(privateBoundNames)
+      this._unresolvedPrivateNamesStack = this._unresolvedPrivateNamesStack || []
+      const unresolvedPrivateNames = Object.create(null)
+      this._unresolvedPrivateNamesStack.push(unresolvedPrivateNames)
+      const _return = super.parseClass(node, isStatement)
+      this._privateBoundNamesStack.pop()
+      this._unresolvedPrivateNamesStack.pop()
+      if (!this._unresolvedPrivateNamesStack.length) {
+        const names = Object.keys(unresolvedPrivateNames)
+        if (names.length) {
+          names.sort((n1, n2) => unresolvedPrivateNames[n1] - unresolvedPrivateNames[n2])
+          this.raise(unresolvedPrivateNames[names[0]], "Usage of undeclared private name")
+        }
+      } else Object.assign(this._unresolvedPrivateNamesStack[this._unresolvedPrivateNamesStack.length - 1], unresolvedPrivateNames)
+      return _return
+    }
+
+    // Parse private element access
+    parseSubscript(base, startPos, startLoc, noCalls, maybeAsyncArrow) {
+      if (!this.eat(tt.dot)) {
+        return super.parseSubscript(base, startPos, startLoc, noCalls, maybeAsyncArrow)
+      }
+      let node = this.startNodeAt(startPos, startLoc)
+      node.object = base
+      node.computed = false
+      if (this.type == this.privateNameToken) {
+        node.property = this.parsePrivateName()
+        if (!this._privateBoundNamesStack.length || !this._privateBoundNamesStack[this._privateBoundNamesStack.length - 1][node.property.name]) {
+          this._unresolvedPrivateNamesStack[this._unresolvedPrivateNamesStack.length - 1][node.property.name] = node.property.start
+        }
+      } else {
+        node.property = this.parseIdent(true)
+      }
+      return this.finishNode(node, "MemberExpression")
+    }
+
+    // Prohibit delete of private class elements
+    parseMaybeUnary(refDestructuringErrors, sawUnary) {
+      const _return = super.parseMaybeUnary(refDestructuringErrors, sawUnary)
+      if (_return.operator == "delete") {
+        if (_return.argument.type == "MemberExpression" && _return.argument.property.type == "PrivateName") {
+          this.raise(_return.start, "Private elements may not be deleted")
+        }
+      }
+      return _return
+    }
+  }
+  Parser.prototype.privateNameToken = new TokenType("privateName")
+  return Parser
+}
diff --git a/deps/acorn-plugins/acorn-private-class-elements/package.json b/deps/acorn-plugins/acorn-private-class-elements/package.json
new file mode 100644
index 0000000000..cd43012dc7
--- /dev/null
+++ b/deps/acorn-plugins/acorn-private-class-elements/package.json
@@ -0,0 +1,63 @@
+{
+  "_from": "acorn-private-class-elements@^0.1.1",
+  "_id": "acorn-private-class-elements@0.1.1",
+  "_inBundle": false,
+  "_integrity": "sha512-bZpmSnaOsK3jkF7J8xaLJ05f008vapPX+XliIv8+jjkclvDR+M4OnTHLhFnCCSeJ0fMwRKjbY+BXsglSNpVZtw==",
+  "_location": "/acorn-private-class-elements",
+  "_phantomChildren": {},
+  "_requested": {
+    "type": "range",
+    "registry": true,
+    "raw": "acorn-private-class-elements@^0.1.1",
+    "name": "acorn-private-class-elements",
+    "escapedName": "acorn-private-class-elements",
+    "rawSpec": "^0.1.1",
+    "saveSpec": null,
+    "fetchSpec": "^0.1.1"
+  },
+  "_requiredBy": [
+    "/acorn-class-fields"
+  ],
+  "_resolved": "https://registry.npmjs.org/acorn-private-class-elements/-/acorn-private-class-elements-0.1.1.tgz",
+  "_shasum": "85209cb5791ab84fde2362cb208fa51e7679bcdc",
+  "_spec": "acorn-private-class-elements@^0.1.1",
+  "_where": "/home/ruben/repos/node/node/node_modules/acorn-class-fields",
+  "bugs": {
+    "url": "https://github.com/acornjs/acorn-private-class-elements/issues"
+  },
+  "bundleDependencies": false,
+  "contributors": [
+    {
+      "name": "Adrian Heine",
+      "email": "mail@adrianheine.de"
+    }
+  ],
+  "dependencies": {
+    "mocha": "^5.2.0"
+  },
+  "deprecated": false,
+  "description": "Helpers for supporting private class methods and fields in acorn",
+  "devDependencies": {
+    "acorn": "^6.1.0",
+    "eslint": "^5.13.0",
+    "eslint-plugin-node": "^8.0.1"
+  },
+  "engines": {
+    "node": ">=4.8.2"
+  },
+  "homepage": "https://github.com/acornjs/acorn-private-class-elements",
+  "license": "MIT",
+  "name": "acorn-private-class-elements",
+  "peerDependencies": {
+    "acorn": "^6.1.0"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/acornjs/acorn-private-class-elements.git"
+  },
+  "scripts": {
+    "lint": "eslint -c .eslintrc.json .",
+    "test": "mocha"
+  },
+  "version": "0.1.1"
+}
diff --git a/deps/acorn-plugins/acorn-private-methods/CHANGELOG.md b/deps/acorn-plugins/acorn-private-methods/CHANGELOG.md
new file mode 100644
index 0000000000..5de4b97b81
--- /dev/null
+++ b/deps/acorn-plugins/acorn-private-methods/CHANGELOG.md
@@ -0,0 +1,29 @@
+## 0.3.0 (2019-02-09)
+
+* Require acorn >= 6.1.0
+
+## 0.2.3 (2019-02-09)
+
+* Forbid binding await in async arrow function's parameter list
+
+## 0.2.2 (2019-01-30)
+
+* Fix parsing of chained subscripts
+
+## 0.2.1 (2018-11-06)
+
+* Adapt to changes in acorn 6.0.3
+
+## 0.2.0 (2018-09-14)
+
+* Update to new acorn 6 interface
+* Change license to MIT
+* Don't allow direct super() calls in private methods
+
+## 0.1.1 (2018-02-09)
+
+* Don't accept whitespace between hash and private name
+
+## 0.1.0 (2018-01-13)
+
+Initial release
diff --git a/deps/acorn-plugins/acorn-private-methods/LICENSE b/deps/acorn-plugins/acorn-private-methods/LICENSE
new file mode 100644
index 0000000000..7c2b27a19c
--- /dev/null
+++ b/deps/acorn-plugins/acorn-private-methods/LICENSE
@@ -0,0 +1,19 @@
+Copyright (C) 2017-2018 by Adrian Heine
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/deps/acorn-plugins/acorn-private-methods/README.md b/deps/acorn-plugins/acorn-private-methods/README.md
new file mode 100644
index 0000000000..6929e84ba6
--- /dev/null
+++ b/deps/acorn-plugins/acorn-private-methods/README.md
@@ -0,0 +1,21 @@
+# Private methods and getter/setters support for Acorn
+
+[![NPM version](https://img.shields.io/npm/v/acorn-private-methods.svg)](https://www.npmjs.org/package/acorn-private-methods)
+
+This is a plugin for [Acorn](http://marijnhaverbeke.nl/acorn/) - a tiny, fast JavaScript parser, written completely in JavaScript.
+
+It implements support for private methods, getters and setters as defined in the stage 3 proposal [Private methods and getter/setters for JavaScript classes](https://github.com/tc39/proposal-private-methods). The emitted AST follows [an ESTree proposal](https://github.com/estree/estree/pull/180).
+
+## Usage
+
+This module provides a plugin that can be used to extend the Acorn `Parser` class:
+
+```javascript
+const {Parser} = require('acorn');
+const privateMethods = require('acorn-private-methods');
+Parser.extend(privateMethods).parse('class X { #a() {} }');
+```
+
+## License
+
+This plugin is released under an [MIT License](./LICENSE).
diff --git a/deps/acorn-plugins/acorn-private-methods/index.js b/deps/acorn-plugins/acorn-private-methods/index.js
new file mode 100644
index 0000000000..a296425168
--- /dev/null
+++ b/deps/acorn-plugins/acorn-private-methods/index.js
@@ -0,0 +1,25 @@
+"use strict"
+
+const privateClassElements = require('internal/deps/acorn-plugins/acorn-private-class-elements/index')
+
+module.exports = function(Parser) {
+  const ExtendedParser = privateClassElements(Parser)
+
+  return class extends ExtendedParser {
+    // Parse private methods
+    parseClassElement(_constructorAllowsSuper) {
+      const oldInClassMemberName = this._inClassMemberName
+      this._inClassMemberName = true
+      const result = super.parseClassElement.apply(this, arguments)
+      this._inClassMemberName = oldInClassMemberName
+      return result
+    }
+
+    parsePropertyName(prop) {
+      const isPrivate = this.options.ecmaVersion >= 8 && this._inClassMemberName && this.type == this.privateNameToken
+      this._inClassMemberName = false
+      if (!isPrivate) return super.parsePropertyName(prop)
+      return this.parsePrivateClassElementName(prop)
+    }
+  }
+}
diff --git a/deps/acorn-plugins/acorn-private-methods/package.json b/deps/acorn-plugins/acorn-private-methods/package.json
new file mode 100644
index 0000000000..d25c611316
--- /dev/null
+++ b/deps/acorn-plugins/acorn-private-methods/package.json
@@ -0,0 +1,68 @@
+{
+  "_from": "acorn-private-methods",
+  "_id": "acorn-private-methods@0.3.0",
+  "_inBundle": false,
+  "_integrity": "sha512-+gWTjSA+13lsv1mwCPosSrLzEyghYtWgrr/1Ck7i7Pu5iK7Ke0hOgw3IW1RUxhc4qS2QTQBQx2+qHYqsa4Qlqw==",
+  "_location": "/acorn-private-methods",
+  "_phantomChildren": {},
+  "_requested": {
+    "type": "tag",
+    "registry": true,
+    "raw": "acorn-private-methods",
+    "name": "acorn-private-methods",
+    "escapedName": "acorn-private-methods",
+    "rawSpec": "",
+    "saveSpec": null,
+    "fetchSpec": "latest"
+  },
+  "_requiredBy": [
+    "#USER",
+    "/"
+  ],
+  "_resolved": "https://registry.npmjs.org/acorn-private-methods/-/acorn-private-methods-0.3.0.tgz",
+  "_shasum": "a5a9f8cd83d175bc138fa22592fababd0afda35d",
+  "_spec": "acorn-private-methods",
+  "_where": "/home/ruben/repos/node/node",
+  "bugs": {
+    "url": "https://github.com/acornjs/acorn-private-methods/issues"
+  },
+  "bundleDependencies": false,
+  "contributors": [
+    {
+      "name": "Adrian Heine",
+      "email": "mail@adrianheine.de"
+    }
+  ],
+  "dependencies": {
+    "acorn-private-class-elements": "^0.1.0"
+  },
+  "deprecated": false,
+  "description": "Support for private methods in acorn",
+  "devDependencies": {
+    "acorn": "^6.1.0",
+    "eslint": "^5.13.0",
+    "eslint-plugin-node": "^8.0.1",
+    "mocha": "^5.2.0",
+    "test262": "git+https://github.com/tc39/test262.git#33a306d1026b72227eb50a918db19ada16f12b3d",
+    "test262-parser-runner": "^0.5.0"
+  },
+  "engines": {
+    "node": ">=4.8.2"
+  },
+  "homepage": "https://github.com/acornjs/acorn-private-methods",
+  "license": "MIT",
+  "name": "acorn-private-methods",
+  "peerDependencies": {
+    "acorn": "^6.1.0"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/acornjs/acorn-private-methods.git"
+  },
+  "scripts": {
+    "lint": "eslint -c .eslintrc.json .",
+    "test": "mocha",
+    "test:test262": "node run_test262.js"
+  },
+  "version": "0.3.0"
+}
diff --git a/deps/acorn-plugins/acorn-static-class-features/CHANGELOG.md b/deps/acorn-plugins/acorn-static-class-features/CHANGELOG.md
new file mode 100644
index 0000000000..b9896a4bc5
--- /dev/null
+++ b/deps/acorn-plugins/acorn-static-class-features/CHANGELOG.md
@@ -0,0 +1,11 @@
+## 0.2.0 (2019-02-09)
+
+* Require acorn >= 6.1.0
+
+## 0.1.1 (2018-11-06)
+
+* Adapt to changes in acorn 6.0.3
+
+## 0.1.0 (2018-09-14)
+
+Initial release
diff --git a/deps/acorn-plugins/acorn-static-class-features/LICENSE b/deps/acorn-plugins/acorn-static-class-features/LICENSE
new file mode 100644
index 0000000000..7c2b27a19c
--- /dev/null
+++ b/deps/acorn-plugins/acorn-static-class-features/LICENSE
@@ -0,0 +1,19 @@
+Copyright (C) 2017-2018 by Adrian Heine
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/deps/acorn-plugins/acorn-static-class-features/README.md b/deps/acorn-plugins/acorn-static-class-features/README.md
new file mode 100644
index 0000000000..bb214fce16
--- /dev/null
+++ b/deps/acorn-plugins/acorn-static-class-features/README.md
@@ -0,0 +1,21 @@
+# Static class features support for Acorn
+
+[![NPM version](https://img.shields.io/npm/v/acorn-class-fields.svg)](https://www.npmjs.org/package/acorn-static-class-features)
+
+This is a plugin for [Acorn](http://marijnhaverbeke.nl/acorn/) - a tiny, fast JavaScript parser, written completely in JavaScript.
+
+It implements support for static class features as defined in the stage 3 proposal [Static class features](https://github.com/tc39/proposal-static-class-features). The emitted AST follows [an ESTree proposal](https://github.com/estree/estree/pull/180).
+
+## Usage
+
+This module provides a plugin that can be used to extend the Acorn `Parser` class:
+
+```javascript
+const {Parser} = require('acorn');
+const staticClassFeatures = require('acorn-static-class-features');
+Parser.extend(staticClassFeatures).parse('class X { static x = 0 }');
+```
+
+## License
+
+This plugin is released under an [MIT License](./LICENSE).
diff --git a/deps/acorn-plugins/acorn-static-class-features/index.js b/deps/acorn-plugins/acorn-static-class-features/index.js
new file mode 100644
index 0000000000..d8954bf327
--- /dev/null
+++ b/deps/acorn-plugins/acorn-static-class-features/index.js
@@ -0,0 +1,126 @@
+"use strict"
+
+const skipWhiteSpace = /(?:\s|\/\/.*|\/\*[^]*?\*\/)*/g
+
+const acorn = require('internal/deps/acorn/acorn/dist/acorn')
+const tt = acorn.tokTypes
+
+function maybeParseFieldValue(field) {
+  if (this.eat(tt.eq)) {
+    const oldInFieldValue = this._inStaticFieldValue
+    this._inStaticFieldValue = true
+    field.value = this.parseExpression()
+    this._inStaticFieldValue = oldInFieldValue
+  } else field.value = null
+}
+
+const privateClassElements = require("internal/deps/acorn-plugins/acorn-private-class-elements/index")
+
+module.exports = function(Parser) {
+  const ExtendedParser = privateClassElements(Parser)
+
+  return class extends ExtendedParser {
+    // Parse private fields
+    parseClassElement(_constructorAllowsSuper) {
+      if (this.eat(tt.semi)) return null
+
+      const node = this.startNode()
+
+      const tryContextual = (k, noLineBreak) => {
+        if (typeof noLineBreak == "undefined") noLineBreak = false
+        const start = this.start, startLoc = this.startLoc
+        if (!this.eatContextual(k)) return false
+        if (this.type !== tt.parenL && (!noLineBreak || !this.canInsertSemicolon())) return true
+        if (node.key) this.unexpected()
+        node.computed = false
+        node.key = this.startNodeAt(start, startLoc)
+        node.key.name = k
+        this.finishNode(node.key, "Identifier")
+        return false
+      }
+
+      node.static = tryContextual("static")
+      if (!node.static) return super.parseClassElement.apply(this, arguments)
+
+      let isGenerator = this.eat(tt.star)
+      let isAsync = false
+      if (!isGenerator) {
+        // Special-case for `async`, since `parseClassMember` currently looks
+        // for `(` to determine whether `async` is a method name
+        if (this.options.ecmaVersion >= 8 && this.isContextual("async")) {
+          skipWhiteSpace.lastIndex = this.pos
+          let skip = skipWhiteSpace.exec(this.input)
+          let next = this.input.charAt(this.pos + skip[0].length)
+          if (next === ";" || next === "=") {
+            node.key = this.parseIdent(true)
+            node.computed = false
+            maybeParseFieldValue.call(this, node)
+            this.finishNode(node, "FieldDefinition")
+            this.semicolon()
+            return node
+          } else if (this.options.ecmaVersion >= 8 && tryContextual("async", true)) {
+            isAsync = true
+            isGenerator = this.options.ecmaVersion >= 9 && this.eat(tt.star)
+          }
+        } else if (tryContextual("get")) {
+          node.kind = "get"
+        } else if (tryContextual("set")) {
+          node.kind = "set"
+        }
+      }
+      if (this.type === this.privateNameToken) {
+        this.parsePrivateClassElementName(node)
+        if (this.type !== tt.parenL) {
+          if (node.key.name === "prototype") {
+            this.raise(node.key.start, "Classes may not have a private static property named prototype")
+          }
+          maybeParseFieldValue.call(this, node)
+          this.finishNode(node, "FieldDefinition")
+          this.semicolon()
+          return node
+        }
+      } else if (!node.key) {
+        this.parsePropertyName(node)
+        if ((node.key.name || node.key.value) === "prototype" && !node.computed) {
+          this.raise(node.key.start, "Classes may not have a static property named prototype")
+        }
+      }
+      if (!node.kind) node.kind = "method"
+      this.parseClassMethod(node, isGenerator, isAsync)
+      if (!node.kind && (node.key.name || node.key.value) === "constructor" && !node.computed) {
+        this.raise(node.key.start, "Classes may not have a static field named constructor")
+      }
+      if (node.kind === "get" && node.value.params.length !== 0) {
+        this.raiseRecoverable(node.value.start, "getter should have no params")
+      }
+      if (node.kind === "set" && node.value.params.length !== 1) {
+        this.raiseRecoverable(node.value.start, "setter should have exactly one param")
+      }
+      if (node.kind === "set" && node.value.params[0].type === "RestElement") {
+        this.raiseRecoverable(node.value.params[0].start, "Setter cannot use rest params")
+      }
+
+      return node
+
+    }
+
+    // Parse public static fields
+    parseClassMethod(method, isGenerator, isAsync, _allowsDirectSuper) {
+      if (isGenerator || isAsync || method.kind != "method" || !method.static || this.options.ecmaVersion < 8 || this.type == tt.parenL) {
+        return super.parseClassMethod.apply(this, arguments)
+      }
+      maybeParseFieldValue.call(this, method)
+      delete method.kind
+      method = this.finishNode(method, "FieldDefinition")
+      this.semicolon()
+      return method
+    }
+
+    // Prohibit arguments in class field initializers
+    parseIdent(liberal, isBinding) {
+      const ident = super.parseIdent(liberal, isBinding)
+      if (this._inStaticFieldValue && ident.name == "arguments") this.raise(ident.start, "A static class field initializer may not contain arguments")
+      return ident
+    }
+  }
+}
diff --git a/deps/acorn-plugins/acorn-static-class-features/package.json b/deps/acorn-plugins/acorn-static-class-features/package.json
new file mode 100644
index 0000000000..ff9ff30c05
--- /dev/null
+++ b/deps/acorn-plugins/acorn-static-class-features/package.json
@@ -0,0 +1,68 @@
+{
+  "_from": "acorn-static-class-features",
+  "_id": "acorn-static-class-features@0.2.0",
+  "_inBundle": false,
+  "_integrity": "sha512-46IooHSRsvgSi+t36Wx9iPfF9BKFKVDcAWELXVqvKHmZogSCk11iUCi2FiZmLeTaM0hlJ3EYDyYiVmHRUGPzWA==",
+  "_location": "/acorn-static-class-features",
+  "_phantomChildren": {},
+  "_requested": {
+    "type": "tag",
+    "registry": true,
+    "raw": "acorn-static-class-features",
+    "name": "acorn-static-class-features",
+    "escapedName": "acorn-static-class-features",
+    "rawSpec": "",
+    "saveSpec": null,
+    "fetchSpec": "latest"
+  },
+  "_requiredBy": [
+    "#USER",
+    "/"
+  ],
+  "_resolved": "https://registry.npmjs.org/acorn-static-class-features/-/acorn-static-class-features-0.2.0.tgz",
+  "_shasum": "8a12b0b280b2e067e268fdbb14116a5b02affd71",
+  "_spec": "acorn-static-class-features",
+  "_where": "/home/ruben/repos/node/node",
+  "bugs": {
+    "url": "https://github.com/acornjs/acorn-static-class-features/issues"
+  },
+  "bundleDependencies": false,
+  "contributors": [
+    {
+      "name": "Adrian Heine",
+      "email": "mail@adrianheine.de"
+    }
+  ],
+  "dependencies": {
+    "acorn-private-class-elements": "^0.1.0"
+  },
+  "deprecated": false,
+  "description": "Support for static class features in acorn",
+  "devDependencies": {
+    "acorn": "^6.1.0",
+    "eslint": "^5.13.0",
+    "eslint-plugin-node": "^8.0.1",
+    "mocha": "^5.2.0",
+    "test262": "git+https://github.com/tc39/test262.git#33a306d1026b72227eb50a918db19ada16f12b3d",
+    "test262-parser-runner": "^0.5.0"
+  },
+  "engines": {
+    "node": ">=4.8.2"
+  },
+  "homepage": "https://github.com/acornjs/acorn-static-class-features",
+  "license": "MIT",
+  "name": "acorn-static-class-features",
+  "peerDependencies": {
+    "acorn": "^6.1.0"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/acornjs/acorn-static-class-features.git"
+  },
+  "scripts": {
+    "lint": "eslint -c .eslintrc.json .",
+    "test": "mocha",
+    "test:test262": "node run_test262.js"
+  },
+  "version": "0.2.0"
+}