v5.6.16

- Don't hoist constant elements to the same function as their original paths function parent.
 - Push each violation paths ancestry to the breakOnScopePaths collection to avoid constant hoisting to nested paths.

.babelrc

@@ -2,5 +2,6 @@
   "stage": 0,
   "loose": ["all"],
   "blacklist": ["es6.tailCall"],
-  "optional": ["optimisation.flow.forOf"]
+  "optional": ["optimisation.flow.forOf"],
+  "plugins": ["./tools/build-plugins/protect"]
 }

.eslintrc

@@ -18,7 +18,8 @@
     "new-cap": 0,
     "no-loop-func": 0,
     "no-unreachable": 0,
-    "no-labels": 0
+    "no-labels": 0,
+    "no-process-exit": 0
   },
   "env": {
     "node": true

.gitignore

@@ -15,3 +15,4 @@ test/core/tmp
 /packages/babel-runtime/helpers/*.js
 /packages/babel-runtime/regenerator/*.js
 /lib
+_babel.github.io

.npmignore

@@ -13,3 +13,4 @@
 /vendor
 /packages
 /src
+_babel.github.io

.travis.yml

@@ -1,14 +1,34 @@
-#sudo: false
 language: node_js
 cache:
   directories:
-    - node_modules
+  - node_modules
 node_js:
-  - "0.12"
-  - "iojs"
+- "0.12"
+- iojs
 
-before_script: "npm install -g codeclimate-test-reporter"
-script: "make test-travis"
+before_script: ./tools/setup-git.sh
+script: make test-travis
+after_success: ./tools/merge-development-with-master.sh
 
 notifications:
   slack: babeljs:5Wy4QX13KVkGy9CnU0rmvgeK
+
+before_deploy:
+- make prepublish
+
+deploy:
+  provider: npm
+  email: sebmck@gmail.com
+  skip_cleanup: true
+  api_key:
+    secure: Q/pZStwherdYPCqCa0aUuiEktLcx6ccBxieyH8j9IXdDgty0ydmnajZfUnlZuCjN13XI9esM44nSJFTWZvntTryDQAQm37c63VXhAEnw/qrAINI06yt0gLBTT69/fKvIAkH8l48nmW32ZS2dse3rHRPZF1CwyQLC/pdMip8I4sM=
+  on:
+    branch: master
+    tags: true
+    repo: babel/babel
+
+after_deploy:
+- make publish-cli
+- make publish-runtime
+- make build-website
+- make comment-issues

CHANGELOG.md

@@ -9,10 +9,70 @@
 > - [Internal]
 > - [Polish]
 
-_Note: Gaps between patch versions are faulty/broken releases._
+_Note: Gaps between patch versions are faulty, broken or test releases._
 
 See [CHANGELOG - 6to5](CHANGELOG-6to5.md) for the pre-4.0.0 version changelog.
 
+## 5.6.12
+
+ * **Bug Fix**
+  * Fix finding parent for top-level shadowed functions.
+
+## 5.6.11
+
+ ** **Internal**
+  * Merge `es6.parameters.rest` and `es6.parameters.default` transformers. See commit [c0fd4c1f9e0b18231f585c4fa793e4cb0e01aed1](https://github.com/babel/babel/commit/c0fd4c1f9e0b18231f585c4fa793e4cb0e01aed1) for more info.
+
+## 5.6.10
+
+ * **Bug Fix**
+  * Fix faulty internal require check.
+ * **Polish**
+  * Add support for trailing commas in arrow function parameter lists.
+
+## 5.6.8
+
+ * **Bug Fix**
+  * Fix binary expressions colliding with unary expression operators in compact mode.
+  * Fix node properties being set to `null` when using computed properties.
+
+## 5.6.7
+
+ * **Bug Fix**
+  * Fix hoisting of `ForXStatement` `left` `var`s when inserting a block scoping IIFE.
+ * **Polish**
+  * Combine all leading computed property initialisers into the root object in loose mode.
+ * **Internal**
+  * Deprecate returning of replacement strings from visitor methods.
+
+## 5.6.6
+
+ * **Bug Fix**
+  * Fix weird parser bug where `void` type annotations were being parsed as keywords causing the tokeniser to lose track of context.
+
+## 5.6.5
+
+ * **Bug Fix**
+  * Fix nested functions causing rest parameter optimisation to not properly detect when it should deopt on a reference.
+ * **Internal**
+  * Update Regenerator `0.8.31`.
+
+## 5.6.4
+
+ * **Internal**
+  * Add `ParenthesizedExpression` node type.
+
+## 5.6.3
+
+ * **Bug Fix**
+  * Fix rest parameter array allocation loop being incorrectly aliased.
+
+## 5.6.2
+
+ * **Bug Fix**
+  * Fix method key literals not turning into computed member expression in loose mode.
+  * Elect rest parameters in spread element position as candidates instead of replacing them in place.
+
 ## 5.6.0
 
  * **Bug Fix**

CONTRIBUTING.md

@@ -113,8 +113,6 @@ your [`$PATH`](http://unix.stackexchange.com/questions/26047/how-to-correctly-ad
 
 + [js-tokens](http://ghub.io/js-tokens) This is used to get tokens for syntax error highlighting.
 
-+ [leven](http://ghub.io/leven) A levenstein algorithm to determine how close a word is to another. This is used to offer suggestions when using the utility.undeclaredVariableCheck transformer.
-
 + [line-numbers](http://ghub.io/line-numbers) Used to produce the code frames in syntax errors.
 
 + [lodash](http://ghub.io/lodash) Used for various utilities.
@@ -145,8 +143,11 @@ your [`$PATH`](http://unix.stackexchange.com/questions/26047/how-to-correctly-ad
 
 + [trim-right](http://ghub.io/trim-right) Trims the rightside whitespace.
 
-+ [user-home](http://ghub.io/user-home) Gets the users home directory. This is used to resolve the babel-node/babel/register cache.
++ [path-exists](https://www.npmjs.com/package/path-exists) Checks if a path exists. (replaces the deprecated `fs.exists` methods)
 
++ [home-or-tmp](https://github.com/sindresorhus/home-or-tmp) Gets the user home directory with fallback to the system temporary directory. This is used to resolve the babel-node/babel/register cache.
+
++ [resolve](https://www.npmjs.com/package/resolve) Implements the [`require.resolve()` algorithm](http://nodejs.org/docs/v0.12.0/api/all.html#all_require_resolve) such that we can `require.resolve()` on behalf of a file asynchronously and synchronously.
 
 #### Code Standards
 

Makefile

@@ -9,7 +9,7 @@ BROWSERIFY_IGNORE = -i esprima-fb
 
 export NODE_ENV = test
 
-.PHONY: clean test test-cov test-clean test-travis test-simple test-all test-browser test-parser publish build bootstrap publish-core publish-runtime build-core watch-core build-core-test clean-core
+.PHONY: clean test test-cov test-clean test-travis test-simple test-all test-browser test-parser publish build bootstrap publish-core publish-runtime build-website build-core watch-core build-core-test clean-core prepublish
 
 build-core: clean-core
 	node $(BABEL_CMD) src --out-dir lib --copy-files
@@ -24,7 +24,7 @@ clean-core:
 	rm -rf lib
 
 lint:
-	eslint src/babel
+	eslint src/babel packages/babel-cli/bin
 
 build:
 	mkdir -p dist
@@ -81,34 +81,20 @@ test-browser:
 
 publish: lint
 	git pull --rebase
-
 	make test
-
 	read -p "Version: " version; \
 	npm version $$version --message "v%s"
-
-	make build
-
-	cp dist/browser.js browser.js
-	cp dist/browser.min.js browser.min.js
-
-	cp dist/polyfill.js browser-polyfill.js
-	cp dist/polyfill.min.js browser-polyfill.min.js
-
-	cp dist/external-helpers.js external-helpers.js
-	cp dist/external-helpers.min.js external-helpers.min.js
-
-	node tools/cache-templates
-	test -f templates.json
-
-	npm publish
-
 	git push --follow-tags
 
-	make publish-cli
-	make publish-runtime
-
-	rm -rf templates.json browser.js browser.min.js browser-polyfill.js browser-polyfill.min.js external-helpers.js external-helpers.min.js
+prepublish: build
+	cp dist/browser.js browser.js
+	cp dist/browser.min.js browser.min.js
+	cp dist/polyfill.js browser-polyfill.js
+	cp dist/polyfill.min.js browser-polyfill.min.js
+	cp dist/external-helpers.js external-helpers.js
+	cp dist/external-helpers.min.js external-helpers.min.js
+	node tools/cache-templates
+	test -f templates.json
 
 publish-runtime:
 	cd packages; \
@@ -117,10 +103,13 @@ publish-runtime:
 	npm publish
 
 publish-cli:
-	cd packages; \
-	node build-cli.js; \
-	cd babel-cli; \
-	npm publish
+	@./tools/publish-cli.sh
+
+build-website:
+	@./tools/build-website.sh
+
+comment-issues:
+	@./tools/comment-issues.sh
 
 bootstrap:
 	npm list --global --depth 1 babel >/dev/null 2>&1 && npm uninstall -g babel || true

README.md

@@ -5,15 +5,24 @@
 </p>
 
 <p align="center">
-  <strong>Babel</strong> is a compiler for writing next generation JavaScript.
+  The compiler for writing next generation JavaScript.
 </p>
 
 <p align="center">
-  For questions and support please visit the <a href="https://babel-slack.herokuapp.com">slack channel</a> or <a href="http://stackoverflow.com/questions/tagged/babeljs">StackOverflow</a>. The Babel issue tracker is <strong>exclusively</strong> for bug reports and feature requests.
+  <a href="https://travis-ci.org/babel/babel"><img alt="Build Status" src="https://img.shields.io/travis/babel/babel.svg?style=flat"></a>
+  <a href="http://badge.fury.io/js/babel-core"><img alt="npm version" src="https://badge.fury.io/js/babel-core.svg"></a>
+  <a href="https://npmjs.org/package/babel-core"><img alt="Downloads" src="http://img.shields.io/npm/dm/babel-core.svg"></a>
 </p>
 
 <p align="center">
-  Issues without instructions to reproduce <strong>will be immediately closed<strong>.
+  <a href="http://issuestats.com/github/babel/babel"><img alt="Issue Stats" src="http://issuestats.com/github/babel/babel/badge/pr?style=flat"></a>
+  <a href="http://issuestats.com/github/babel/babel"><img alt="Issue Stats" src="http://issuestats.com/github/babel/babel/badge/issue?style=flat"></a>
+</p>
+
+----
+
+<p align="center">
+  For questions and support please visit the <a href="https://babel-slack.herokuapp.com">Slack community</a> or <a href="http://stackoverflow.com/questions/tagged/babeljs">StackOverflow</a>. The Babel issue tracker is <strong>exclusively</strong> for bug reports and feature requests.
 </p>
 
 <p align="center">

doc/node-props.md

@@ -1,5 +1,5 @@
 # Properties of nodes
-These are properties babel stores in AST node objects for internal use, as opposed to properties that are part of the AST spec (ESTree at the time of this writing).
+These are properties babel stores in AST node objects for internal use, as opposed to properties that are part of the AST spec ([ESTree](https://github.com/estree/estree) at the time of this writing).
 
 ## `_blockHoist`
 `node._blockHoist != null` triggers the [block-hoist transformer](/src/babel/transformation/transformers/internal/block-hoist.js). Value should be `true` or an integer in the range `0..3`. `true` is equivalent to `2`. The value indicates whether the node should be hoisted and to what degree. See the source code for more detailed information.
@@ -8,4 +8,4 @@ These are properties babel stores in AST node objects for internal use, as oppos
 Stores a representation of a node's position in the tree and relationship to other nodes.
 
 ## `shadow`
-A truthy value on a function node triggers the [shadow-functions transformer](/src/babel/transformation/transformers/internal/shadow-functions.js), which transforms the node so that it references (or inherits) `arguments` and `this` from the parent scope. It is invoked for arrow functions, for example.
+A truthy value on a function node triggers the [shadow-functions transformer](/src/babel/transformation/transformers/internal/shadow-functions.js), which transforms the node so that it references (or inherits) `arguments` and the `this` context from the parent scope. It is invoked for arrow functions, for example.

index.js

@@ -0,0 +1 @@
+module.exports = require("./lib/babel/api/node.js");

package.json

@@ -1,27 +1,26 @@
 {
   "name": "babel-core",
   "description": "A compiler for writing next generation JavaScript",
-  "version": "5.6.2",
+  "version": "5.6.16",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://babeljs.io/",
   "license": "MIT",
   "repository": "babel/babel",
-  "main": "lib/babel/api/node.js",
   "browser": {
     "./lib/babel/api/register/node.js": "./lib/babel/api/register/browser.js"
   },
   "keywords": [
-    "harmony",
+    "6to5",
+    "babel",
     "classes",
-    "modules",
-    "let",
     "const",
-    "var",
     "es6",
+    "harmony",
+    "let",
+    "modules",
     "transpile",
     "transpiler",
-    "6to5",
-    "babel"
+    "var"
   ],
   "scripts": {
     "bench": "make bench",
@@ -31,7 +30,7 @@
     "acorn-jsx": "^1.0.0",
     "ast-types": "~0.7.0",
     "babel-plugin-constant-folding": "^1.0.1",
-    "babel-plugin-dead-code-elimination": "^1.0.1",
+    "babel-plugin-dead-code-elimination": "^1.0.2",
     "babel-plugin-eval": "^1.0.1",
     "babel-plugin-inline-environment-variables": "^1.0.1",
     "babel-plugin-jscript": "^1.0.1",
@@ -57,14 +56,15 @@
     "home-or-tmp": "^1.0.0",
     "is-integer": "^1.0.4",
     "js-tokens": "1.0.1",
-    "leven": "^1.0.1",
     "line-numbers": "0.2.0",
     "lodash": "^3.6.0",
     "minimatch": "^2.0.3",
     "output-file-sync": "^1.1.0",
+    "path-exists": "^1.0.0",
     "path-is-absolute": "^1.0.0",
     "private": "^0.1.6",
-    "regenerator": "0.8.30",
+    "recast": "0.10.16",
+    "regenerator": "0.8.32",
     "regexpu": "^1.1.2",
     "repeating": "^1.1.2",
     "resolve": "^1.1.6",
@@ -77,11 +77,11 @@
     "trim-right": "^1.0.0"
   },
   "devDependencies": {
-    "babel": "5.5.7",
+    "babel": "5.6.10",
+    "babel-eslint": "^3.1.19",
     "browserify": "^9.0.8",
     "chai": "^2.2.0",
     "eslint": "^0.21.2",
-    "babel-eslint": "^3.1.9",
     "esvalid": "^1.1.0",
     "istanbul": "^0.3.5",
     "matcha": "^0.6.0",

packages/babel-cli/bin/_babel-node

@@ -41,6 +41,7 @@ babel.register({
 //
 
 var _eval = function (code, filename) {
+  code = code.trim();
   if (!code) return undefined;
 
   code = babel.transform(code, {

packages/babel-cli/bin/babel-plugin/index.js

@@ -1,9 +1,10 @@
 #!/usr/bin/env node
 
-var readline = require("readline");
-var child    = require("child_process");
-var path     = require("path");
-var fs       = require("fs");
+var pathExists = require("path-exists");
+var readline   = require("readline");
+var child      = require("child_process");
+var path       = require("path");
+var fs         = require("fs");
 
 function spawn(cmd, args, callback) {
   console.log(">", cmd, args);
@@ -34,7 +35,7 @@ function spawnMultiple(cmds) {
 }
 
 function template(name, data) {
-  var source = fs.readFileSync(__dirname + "/templates/" + name, "utf8");
+  var source = fs.readFileSync(path.join(__dirname, "templates", name), "utf8");
   source = source.replace(/[A-Z_]+/g, function (key) {
     return data[key] === undefined ? key : data[key];
   });
@@ -98,7 +99,7 @@ var cmds = {
 
         write("README.md", template("README.md", templateData));
 
-        if (!fs.existsSync("src")) {
+        if (!pathExists.sync("src")) {
           fs.mkdirSync("src");
           write("src/index.js", template("index.js", templateData));
         }

packages/babel-cli/bin/babel/dir.js

@@ -1,4 +1,5 @@
 var outputFileSync = require("output-file-sync");
+var pathExists     = require("path-exists");
 var chokidar       = require("chokidar");
 var slash          = require("slash");
 var path           = require("path");
@@ -6,7 +7,7 @@ var util           = require("./util");
 var fs             = require("fs");
 var _              = require("lodash");
 
-module.exports = function (commander, filenames, opts) {
+module.exports = function (commander, filenames) {
   var write = function (src, relative) {
     // remove extension and then append back on .js
     relative = relative.replace(/\.(\w*?)$/, "") + ".js";
@@ -27,7 +28,7 @@ module.exports = function (commander, filenames, opts) {
 
     outputFileSync(dest, data.code);
 
-    console.log(src + " -> " + dest);
+    util.log(src + " -> " + dest);
   };
 
   var handleFile = function (src, filename) {
@@ -41,7 +42,7 @@ module.exports = function (commander, filenames, opts) {
   };
 
   var handle = function (filename) {
-    if (!fs.existsSync(filename)) return;
+    if (!pathExists.sync(filename)) return;
 
     var stat = fs.statSync(filename);
 

packages/babel-cli/bin/babel/file.js

@@ -1,4 +1,5 @@
 var convertSourceMap = require("convert-source-map");
+var pathExists       = require("path-exists");
 var sourceMap        = require("source-map");
 var chokidar         = require("chokidar");
 var slash            = require("slash");
@@ -100,7 +101,7 @@ module.exports = function (commander, filenames, opts) {
     results = [];
 
     _.each(filenames, function (filename) {
-      if (!fs.existsSync(filename)) return;
+      if (!pathExists.sync(filename)) return;
 
       var stat = fs.statSync(filename);
       if (stat.isDirectory()) {
@@ -134,7 +135,7 @@ module.exports = function (commander, filenames, opts) {
         ignoreInitial: true
       }).on("all", function (type, filename) {
         if (type === "add" || type === "change") {
-          console.log(type, filename);
+          util.log(type + " " + filename);
           try {
             walk();
           } catch (err) {

packages/babel-cli/bin/babel/index.js

@@ -1,6 +1,9 @@
 #!/usr/bin/env node
 
+require("babel-core");
+
 var moduleFormatters = require("babel-core/lib/babel/transformation/modules");
+var pathExists       = require("path-exists");
 var commander        = require("commander");
 var transform        = require("babel-core").transform;
 var kebabCase        = require("lodash/string/kebabCase");
@@ -9,7 +12,6 @@ var util             = require("babel-core").util;
 var uniq             = require("lodash/array/uniq");
 var each             = require("lodash/collection/each");
 var keys             = require("lodash/object/keys");
-var fs               = require("fs");
 var glob             = require("glob");
 
 each(options, function (option, key) {
@@ -43,6 +45,7 @@ commander.option("-w, --watch", "Recompile files on changes");
 commander.option("-o, --out-file [out]", "Compile all input files into a single file");
 commander.option("-d, --out-dir [out]", "Compile an input directory of modules into an output directory");
 commander.option("-D, --copy-files", "When compiling a directory copy over non-compilable files");
+commander.option("-q, --quiet", "Don't log anything");
 
 commander.on("--help", function () {
   var outKeys = function (title, obj) {
@@ -65,7 +68,7 @@ commander.on("--help", function () {
 });
 
 var pkg = require("../../package.json");
-commander.version(pkg.version);
+commander.version(pkg.version + " (babel-core " + require("babel-core").version + ")");
 commander.usage("[options] <files ...>");
 commander.parse(process.argv);
 
@@ -88,7 +91,7 @@ var filenames = commander.args.reduce(function (globbed, input) {
 filenames = uniq(filenames);
 
 each(filenames, function (filename) {
-  if (!fs.existsSync(filename)) {
+  if (!pathExists.sync(filename)) {
     errors.push(filename + " doesn't exist");
   }
 });

packages/babel-cli/bin/babel/util.js

@@ -25,6 +25,10 @@ exports.addSourceMappingUrl = function (code, loc) {
   return code + "\n//# sourceMappingURL=" + path.basename(loc);
 };
 
+exports.log = function (msg) {
+  if (!commander.quiet) console.log(msg);
+};
+
 exports.transform = function (filename, code, opts) {
   opts = _.defaults(opts || {}, index.opts);
   opts.filename = filename;

packages/babel-cli/package.json

@@ -1,14 +1,12 @@
 {
   "name": "babel",
   "description": "Turn ES6 code into readable vanilla ES5 with source maps",
-  "version": "5.6.1",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://babeljs.io/",
   "license": "MIT",
   "repository": "babel/babel",
   "preferGlobal": true,
   "dependencies": {
-    "babel-core": "^5.6.1",
     "chokidar": "^1.0.0",
     "commander": "^2.6.0",
     "convert-source-map": "^1.1.0",
@@ -16,6 +14,7 @@
     "glob": "^5.0.5",
     "lodash": "^3.2.0",
     "output-file-sync": "^1.1.0",
+    "path-exists": "^1.0.0",
     "path-is-absolute": "^1.0.0",
     "source-map": "^0.4.0",
     "slash": "^1.0.0"
@@ -26,4 +25,4 @@
     "babel-external-helpers": "./bin/babel-external-helpers",
     "babel-plugin": "./bin/babel-plugin/index.js"
   }
-}
+}

packages/babel-runtime/package.json

@@ -1,11 +1,10 @@
 {
   "name": "babel-runtime",
   "description": "babel selfContained runtime",
-  "version": "5.6.1",
   "license": "MIT",
   "repository": "babel/babel",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "dependencies": {
     "core-js": "^0.9.0"
   }
-}
+}

packages/build-runtime.js

@@ -73,7 +73,6 @@ each(File.helpers, function (helperName) {
 writeFile("regenerator/index.js", readFile("regenerator/runtime-module", true));
 writeFile("regenerator/runtime.js", selfContainify(readFile("regenerator/runtime")));
 
-//
 
 var coreDefinitions = require("babel-plugin-runtime/lib/definitions");
 
@@ -93,6 +92,5 @@ each(paths, function (path) {
   writeFile("core-js/" + path + ".js", defaultify('require("core-js/library/fn/' + path + '")'));
 });
 
-//
 
 updatePackage();

src/acorn/plugins/flow.js

@@ -15,6 +15,15 @@ pp.expectRelational = function (op) {
   }
 }
 
+pp.flow_parseTypeInitialiser = function (tok) {
+  var oldInType = this.inType
+  this.inType = true
+  this.expect(tok || tt.colon)
+  var type = this.flow_parseType()
+  this.inType = oldInType
+  return type;
+}
+
 pp.flow_parseDeclareClass = function (node) {
   this.next()
   this.flow_parseInterfaceish(node, true)
@@ -40,9 +49,7 @@ pp.flow_parseDeclareFunction = function (node) {
   typeNode.params = tmp.params
   typeNode.rest = tmp.rest
   this.expect(tt.parenR)
-
-  this.expect(tt.colon)
-  typeNode.returnType = this.flow_parseType()
+  typeNode.returnType = this.flow_parseTypeInitialiser()
 
   typeContainer.typeAnnotation = this.finishNode(typeNode, "FunctionTypeAnnotation")
   id.typeAnnotation = this.finishNode(typeContainer, "TypeAnnotation")
@@ -153,15 +160,7 @@ pp.flow_parseTypeAlias = function (node) {
     node.typeParameters = null
   }
 
-  var oldInType = this.inType;
-  this.inType = true;
-
-  this.expect(tt.eq)
-
-  node.right = this.flow_parseType()
-
-  this.inType = oldInType;
-
+  node.right = this.flow_parseTypeInitialiser(tt.eq)
   this.semicolon()
 
   return this.finishNode(node, "TypeAlias")
@@ -214,11 +213,9 @@ pp.flow_parseObjectTypeIndexer = function (node, isStatic) {
 
   this.expect(tt.bracketL)
   node.id = this.flow_parseObjectPropertyKey()
-  this.expect(tt.colon)
-  node.key = this.flow_parseType()
+  node.key = this.flow_parseTypeInitialiser()
   this.expect(tt.bracketR)
-  this.expect(tt.colon)
-  node.value = this.flow_parseType()
+  node.value = this.flow_parseTypeInitialiser()
 
   this.flow_objectTypeSemicolon()
   return this.finishNode(node, "ObjectTypeIndexer")
@@ -245,8 +242,7 @@ pp.flow_parseObjectTypeMethodish = function (node) {
     node.rest = this.flow_parseFunctionTypeParam()
   }
   this.expect(tt.parenR)
-  this.expect(tt.colon)
-  node.returnType = this.flow_parseType()
+  node.returnType = this.flow_parseTypeInitialiser()
 
   return this.finishNode(node, "FunctionTypeAnnotation")
 }
@@ -265,7 +261,7 @@ pp.flow_parseObjectTypeCallProperty = function (node, isStatic) {
   var valueNode = this.startNode()
   node.static = isStatic
   node.value = this.flow_parseObjectTypeMethodish(valueNode)
-    this.flow_objectTypeSemicolon()
+  this.flow_objectTypeSemicolon()
   return this.finishNode(node, "ObjectTypeCallProperty")
 }
 
@@ -310,9 +306,8 @@ pp.flow_parseObjectType = function (allowStatic) {
         if (this.eat(tt.question)) {
           optional = true
         }
-        this.expect(tt.colon)
         node.key = propertyKey
-        node.value = this.flow_parseType()
+        node.value = this.flow_parseTypeInitialiser()
         node.optional = optional
         node.static = isStatic
         this.flow_objectTypeSemicolon()
@@ -352,12 +347,6 @@ pp.flow_parseGenericType = function (start, id) {
   return this.finishNode(node, "GenericTypeAnnotation")
 }
 
-pp.flow_parseVoidType = function () {
-  var node = this.startNode()
-  this.expect(tt._void)
-  return this.finishNode(node, "VoidTypeAnnotation")
-}
-
 pp.flow_parseTypeofType = function () {
   var node = this.startNode()
   this.expect(tt._typeof)
@@ -386,9 +375,8 @@ pp.flow_parseFunctionTypeParam = function () {
   if (this.eat(tt.question)) {
     optional = true
   }
-  this.expect(tt.colon)
   node.optional = optional
-  node.typeAnnotation = this.flow_parseType()
+  node.typeAnnotation = this.flow_parseTypeInitialiser()
   return this.finishNode(node, "FunctionTypeParam")
 }
 
@@ -411,6 +399,9 @@ pp.flow_identToTypeAnnotation = function (start, node, id) {
     case "any":
       return this.finishNode(node, "AnyTypeAnnotation")
 
+    case "void":
+      return this.finishNode(node, "VoidTypeAnnotation")
+
     case "bool":
     case "boolean":
       return this.finishNode(node, "BooleanTypeAnnotation")
@@ -524,14 +515,8 @@ pp.flow_parsePrimaryType = function () {
       return this.finishNode(node, "StringLiteralTypeAnnotation")
 
     default:
-      if (this.type.keyword) {
-        switch (this.type.keyword) {
-          case "void":
-            return this.flow_parseVoidType()
-
-          case "typeof":
-            return this.flow_parseTypeofType()
-        }
+      if (this.type.keyword === "typeof") {
+        return this.flow_parseTypeofType()
       }
   }
 
@@ -588,13 +573,7 @@ pp.flow_parseType = function () {
 
 pp.flow_parseTypeAnnotation = function () {
   var node = this.startNode()
-
-  var oldInType = this.inType
-  this.inType = true
-  this.expect(tt.colon)
-  node.typeAnnotation = this.flow_parseType()
-  this.inType = oldInType
-
+  node.typeAnnotation = this.flow_parseTypeInitialiser()
   return this.finishNode(node, "TypeAnnotation")
 }
 
@@ -694,6 +673,18 @@ acorn.plugins.flow = function (instance) {
     }
   })
 
+  // don't consider `void` to be a keyword as then it'll use the void token type
+  // and set startExpr
+  instance.extend("isKeyword", function (inner) {
+    return function(name) {
+      if (this.inType && name === "void") {
+        return false
+      } else {
+        return inner.call(this, name)
+      }
+    }
+  })
+
   instance.extend("readToken", function (inner) {
     return function(code) {
       if (this.inType && (code === 62 || code === 60)) {

src/acorn/src/expression.js

@@ -432,9 +432,18 @@ pp.parseParenAndDistinguishExpression = function(start, isAsync, canBeArrow) {
     }
 
     let innerStart = this.markPosition(), exprList = [], first = true
-    let refShorthandDefaultPos = {start: 0}, spreadStart, innerParenStart
+    let refShorthandDefaultPos = {start: 0}, spreadStart, innerParenStart, optionalCommaStart
     while (this.type !== tt.parenR) {
-      first ? first = false : this.expect(tt.comma)
+      if (first) {
+        first = false;
+      } else {
+        this.expect(tt.comma)
+        if (this.type === tt.parenR && this.options.features["es7.trailingFunctionCommas"]) {
+          optionalCommaStart = this.start
+          break
+        }
+      }
+
       if (this.type === tt.ellipsis) {
         let spreadNodeStart = this.markPosition()
         spreadStart = this.start
@@ -462,6 +471,7 @@ pp.parseParenAndDistinguishExpression = function(start, isAsync, canBeArrow) {
         this.unexpected(this.lastTokStart)
       }
     }
+    if (optionalCommaStart) this.unexpected(optionalCommaStart)
     if (spreadStart) this.unexpected(spreadStart)
     if (refShorthandDefaultPos.start) this.unexpected(refShorthandDefaultPos.start)
 

src/acorn/src/lookahead.js

@@ -19,7 +19,11 @@ var STATE_KEYS = [
   "exprAllowed",
   "potentialArrowAt",
   "currLine",
-  "input"
+  "input",
+  "inType",
+  "inFunction",
+  "inGenerator",
+  "labels"
 ];
 
 pp.getState = function () {
@@ -29,6 +33,7 @@ pp.getState = function () {
     state[key] = this[key]
   }
   state.context = this.context.slice()
+  state.labels = this.labels.slice()
   return state
 };
 

src/acorn/src/state.js

@@ -4,11 +4,11 @@ import {lineBreak} from "./whitespace"
 
 export function Parser(options, input, startPos) {
   this.options = options
-  this.loadPlugins(this.options.plugins)
   this.sourceFile = this.options.sourceFile || null
   this.isKeyword = keywords[this.options.ecmaVersion >= 6 ? 6 : 5]
   this.isReservedWord = reservedWords[this.options.ecmaVersion]
   this.input = input
+  this.loadPlugins(this.options.plugins)
 
   // Set up token state
 

src/acorn/src/tokentype.js

@@ -112,7 +112,7 @@ kw("case", beforeExpr)
 kw("catch")
 kw("continue")
 kw("debugger")
-kw("default")
+kw("default", beforeExpr)
 kw("do", {isLoop: true})
 kw("else", beforeExpr)
 kw("finally")

src/babel/api/register/cache.js

@@ -1,6 +1,7 @@
 import path from "path";
 import fs from "fs";
 import homeOrTmp from "home-or-tmp";
+import pathExists from "path-exists";
 
 const FILENAME = process.env.BABEL_CACHE_PATH || path.join(homeOrTmp, ".babel.json");
 var data = {};
@@ -15,7 +16,7 @@ export function load() {
   process.on("exit", save);
   process.nextTick(save);
 
-  if (!fs.existsSync(FILENAME)) return;
+  if (!pathExists.sync(FILENAME)) return;
 
   try {
     data = JSON.parse(fs.readFileSync(FILENAME));

src/babel/generation/buffer.js

@@ -54,9 +54,10 @@ export default class Buffer {
     this.space();
   }
 
-  space() {
-    if (this.format.compact) return;
-    if (this.buf && !this.isLast(" ") && !this.isLast("\n")) {
+  space(force?) {
+    if (!force && this.format.compact) return;
+
+    if (force || this.buf && !this.isLast(" ") && !this.isLast("\n")) {
       this.push(" ");
     }
   }
@@ -155,8 +156,12 @@ export default class Buffer {
     this.buf += str;
   }
 
-  endsWith(str) {
-    return this.buf.slice(-str.length) === str;
+  endsWith(str, buf = this.buf) {
+    if (str.length === 1) {
+      return buf[buf.length - 1] === str;
+    } else {
+      return buf.slice(-str.length) === str;
+    }
   }
 
   isLast(cha) {

src/babel/generation/generators/classes.js

@@ -1,5 +1,5 @@
 export function ClassDeclaration(node, print) {
-  print.list(node.decorators);
+  print.list(node.decorators, { separator: "" });
   this.push("class");
 
   if (node.id) {
@@ -43,7 +43,7 @@ export function ClassBody(node, print) {
 
 
 export function ClassProperty(node, print) {
-  print.list(node.decorators);
+  print.list(node.decorators, { separator: "" });
 
   if (node.static) this.push("static ");
   print.plain(node.key);
@@ -58,7 +58,7 @@ export function ClassProperty(node, print) {
 }
 
 export function MethodDefinition(node, print) {
-  print.list(node.decorators);
+  print.list(node.decorators, { separator: "" });
 
   if (node.static) {
     this.push("static ");

src/babel/generation/generators/expressions.js

@@ -2,19 +2,19 @@ import isNumber from "lodash/lang/isNumber";
 import * as t from "../../types";
 
 export function UnaryExpression(node, print) {
-  var hasSpace = /[a-z]$/.test(node.operator);
+  var needsSpace = /[a-z]$/.test(node.operator);
   var arg = node.argument;
 
   if (t.isUpdateExpression(arg) || t.isUnaryExpression(arg)) {
-    hasSpace = true;
+    needsSpace = true;
   }
 
   if (t.isUnaryExpression(arg) && arg.operator === "!") {
-    hasSpace = false;
+    needsSpace = false;
   }
 
   this.push(node.operator);
-  if (hasSpace) this.push(" ");
+  if (needsSpace) this.push(" ");
   print.plain(node.argument);
 }
 
@@ -24,6 +24,12 @@ export function DoExpression(node, print) {
   print.plain(node.body);
 }
 
+export function ParenthesizedExpression(node, print) {
+  this.push("(");
+  print.plain(node.expression);
+  this.push(")");
+}
+
 export function UpdateExpression(node, print) {
   if (node.prefix) {
     this.push(node.operator);
@@ -77,19 +83,16 @@ export function CallExpression(node, print) {
 
   this.push("(");
 
-  var separator = ",";
-
-  var isPrettyCall = node._prettyCall && !this.format.retainLines;
+  var isPrettyCall = node._prettyCall && !this.format.retainLines && !this.format.compact;
 
+  var separator;
   if (isPrettyCall) {
-    separator += "\n";
+    separator = ",\n";
     this.newline();
     this.indent();
-  } else {
-    separator += " ";
   }
 
-  print.list(node.arguments, { separator: separator });
+  print.list(node.arguments, { separator });
 
   if (isPrettyCall) {
     this.newline();
@@ -135,9 +138,23 @@ export function AssignmentPattern(node, print) {
 export function AssignmentExpression(node, print) {
   // todo: add cases where the spaces can be dropped when in compact mode
   print.plain(node.left);
-  this.push(" ");
+
+  var spaces = node.operator === "in" || node.operator === "instanceof";
+  spaces = true; // todo: https://github.com/babel/babel/issues/1835
+  this.space(spaces);
+
   this.push(node.operator);
-  this.push(" ");
+
+  if (!spaces) {
+    // space is mandatory to avoid outputting <!--
+    // http://javascript.spec.whatwg.org/#comment-syntax
+    spaces = node.operator === "<" &&
+             t.isUnaryExpression(node.right, { prefix: true, operator: "!" }) &&
+             t.isUnaryExpression(node.right.argument, { prefix: true, operator: "--" });
+  }
+
+  this.space(spaces);
+
   print.plain(node.right);
 }
 

src/babel/generation/generators/methods.js

@@ -42,7 +42,7 @@ export function _method(node, print) {
   }
 
   this._params(value, print);
-  this.push(" ");
+  this.space();
   print.plain(value.body);
 }
 

src/babel/generation/generators/statements.js

@@ -33,13 +33,13 @@ export function ForStatement(node, print) {
   this.push(";");
 
   if (node.test) {
-    this.push(" ");
+    this.space();
     print.plain(node.test);
   }
   this.push(";");
 
   if (node.update) {
-    this.push(" ");
+    this.space();
     print.plain(node.update);
   }
 
@@ -190,16 +190,29 @@ export function VariableDeclaration(node, print, parent) {
     }
   }
 
-  var sep = ",";
+  //
+  // use a pretty separator when we aren't in compact mode, have initializers and don't have retainLines on
+  // this will format declarations like:
+  //
+  //   var foo = "bar", bar = "foo";
+  //
+  // into
+  //
+  //   var foo = "bar",
+  //       bar = "foo";
+  //
+
+  var sep;
   if (!this.format.compact && !this.format.concise && hasInits && !this.format.retainLines) {
-    sep += `\n${repeating(" ", node.kind.length + 1)}`;
-  } else {
-    sep += " ";
+    sep = `,\n${repeating(" ", node.kind.length + 1)}`;
   }
 
+  //
+
   print.list(node.declarations, { separator: sep });
 
   if (t.isFor(parent)) {
+    // don't give semicolons to these nodes since they'll be inserted in the parent generator
     if (parent.left === node || parent.init === node) return;
   }
 

src/babel/generation/generators/types.js

@@ -33,6 +33,8 @@ export function ObjectExpression(node, print) {
 export { ObjectExpression as ObjectPattern };
 
 export function Property(node, print) {
+  print.list(node.decorators, { separator: "" });
+
   if (node.method || node.kind === "get" || node.kind === "set") {
     this._method(node, print);
   } else {
@@ -80,7 +82,7 @@ export function ArrayExpression(node, print) {
       // both (all) of the holes.
       this.push(",");
     } else {
-      if (i > 0) this.push(" ");
+      if (i > 0) this.space();
       print.plain(elem);
       if (i < len - 1) this.push(",");
     }

src/babel/generation/index.js

@@ -57,34 +57,16 @@ class CodeGenerator {
     return format;
   }
 
-  static findCommonStringDelimiter(code, tokens) {
-    var occurences = {
-      single: 0,
-      double: 0
-    };
-
-    var checked = 0;
-
-    for (var i = 0; i < tokens.length; i++) {
-      var token = tokens[i];
-      if (token.type.label !== "string") continue;
-
-      var raw = code.slice(token.start, token.end);
-      if (raw[0] === "'") {
-        occurences.single++;
-      } else {
-        occurences.double++;
-      }
-
-      checked++;
-      if (checked >= 3) break;
+  static findCommonStringDelimiter(code, tokens, occurences = {"'": 0, "\"": 0}) {
+    if (tokens.length === 0 || occurences["'"] + occurences["\""] >= 3) {
+      return occurences["'"] > occurences["\""] ? "single" : "double";
     }
 
-    if (occurences.single > occurences.double) {
-      return "single";
-    } else {
-      return "double";
+    if (tokens[0].type.label === "string") {
+      occurences[code[tokens[0].start]]++;
     }
+
+    return this.findCommonStringDelimiter(code, tokens.slice(1), occurences);
   }
 
   static generators = {
@@ -128,8 +110,7 @@ class CodeGenerator {
     // catch up to this nodes newline if we're behind
     if (node.loc && this.format.retainLines && this.buffer.buf) {
       var needsParens = false;
-      if (!leftParenPrinted && parent &&
-          this.position.line < node.loc.start.line && t.isTerminatorless(parent)) {
+      if (!leftParenPrinted && parent && this.position.line < node.loc.start.line && t.isTerminatorless(parent)) {
         needsParens = true;
         this._push("(");
       }

src/babel/generation/node/printer.js

@@ -18,7 +18,11 @@ export default class NodePrinter {
   }
 
   list(items, opts = {}) {
-    if (opts.separator == null) opts.separator = ", ";
+    if (opts.separator == null) {
+      opts.separator = ",";
+      if (!this.generator.format.compact) opts.separator += " ";
+    }
+
     return this.join(items, opts);
   }
 

src/babel/messages.js

@@ -1,7 +1,7 @@
 import * as util from  "util";
 
 export const MESSAGES = {
-  tailCallReassignmentDeopt: "Function reference has been reassigned so it's probably be dereferenced so we can't optimise this with confidence",
+  tailCallReassignmentDeopt: "Function reference has been reassigned, so it will probably be dereferenced, therefore we can't optimise this with confidence",
   JSXNamespacedTags: "Namespace tags are not supported. ReactJSX is not XML.",
   classesIllegalBareSuper: "Illegal use of bare super",
   classesIllegalSuperCall: "Direct super call is illegal in non-constructor, use super.$1() instead",
@@ -17,7 +17,7 @@ export const MESSAGES = {
   missingTemplatesDirectory: "no templates directory - this is most likely the result of a broken `npm publish`. Please report to https://github.com/babel/babel/issues",
   unsupportedOutputType: "Unsupported output type $1",
   illegalMethodName: "Illegal method name $1",
-  lostTrackNodePath: "We lost track of this nodes position, likely because the AST was directly manipulated",
+  lostTrackNodePath: "We lost track of this node's position, likely because the AST was directly manipulated",
 
   modulesIllegalExportName: "Illegal export $1",
   modulesDuplicateDeclarations: "Duplicate module declarations with the same source but in different scopes",
@@ -26,7 +26,7 @@ export const MESSAGES = {
   undeclaredVariableType: "Referencing a type alias outside of a type annotation",
   undeclaredVariableSuggestion: "Reference to undeclared variable $1 - did you mean $2?",
 
-  traverseNeedsParent: "Must pass a scope and parentPath unless traversing a Program/File got a $1 node",
+  traverseNeedsParent: "You must pass a scope and parentPath unless traversing a Program/File got a $1 node",
   traverseVerifyRootFunction: "You passed `traverse()` a function when it expected a visitor object, are you sure you didn't mean `{ enter: Function }`?",
   traverseVerifyVisitorProperty: "You passed `traverse()` a visitor object with the property $1 that has the invalid property $2",
   traverseVerifyNodeType: "You gave us a visitor for the node type $1 but it's not a valid type",
@@ -37,7 +37,7 @@ export const MESSAGES = {
   pluginNotTransformer: "The plugin $1 didn't export a Plugin instance",
   pluginUnknown: "Unknown plugin $1",
 
-  pluginNotFile: "Plugin $1 is resolving to a different Babel version to what is doing the actual transformation..."
+  pluginNotFile: "Plugin $1 is resolving to a different Babel version than what is performing the transformation."
 };
 
 export function get(key: String, ...args) {

src/babel/tools/protect.js

@@ -0,0 +1,9 @@
+import path from "path";
+
+var root = path.resolve(__dirname, "../../../");
+
+export default function (module) {
+  if (module.parent && module.parent.filename.indexOf(root) !== 0) {
+    throw new Error("Don't hotlink internal Babel files.");
+  }
+}

src/babel/transformation/file/logger.js

@@ -4,6 +4,8 @@ import buildDebug from "debug/node";
 var verboseDebug = buildDebug("babel:verbose");
 var generalDebug = buildDebug("babel");
 
+var seenDeprecatedMessages = [];
+
 export default class Logger {
   constructor(file: File, filename: string) {
     this.filename = filename;
@@ -25,9 +27,17 @@ export default class Logger {
   }
 
   deprecate(msg) {
-    if (!this.file.opts.suppressDeprecationMessages) {
-      console.error(this._buildMessage(msg));
-    }
+    if (this.file.opts.suppressDeprecationMessages) return;
+
+    msg = this._buildMessage(msg);
+
+    // already seen this message
+    if (seenDeprecatedMessages.indexOf(msg) >= 0) return;
+
+    // make sure we don't see it again
+    seenDeprecatedMessages.push(msg);
+
+    console.error(msg);
   }
 
   verbose(msg: string) {

src/babel/transformation/file/options/resolve-rc.js

@@ -3,16 +3,15 @@ import { normaliseOptions } from "./index";
 import merge from "../../../helpers/merge";
 import path from "path";
 import fs from "fs";
+import pathExists from "path-exists";
 
 var cache = {};
 var jsons = {};
 
 function exists(filename) {
-  if (!fs.existsSync) return false;
-
   var cached = cache[filename];
   if (cached != null) return cached;
-  return cache[filename] = fs.existsSync(filename);
+  return cache[filename] = pathExists.sync(filename);
 }
 
 export default function (loc, opts = {}) {

src/babel/transformation/modules/system.js

@@ -33,8 +33,7 @@ var hoistVariablesVisitor = {
     }
 
     // for (var i in test)
-    // for (var i = 0;;)
-    if (t.isFor(parent) && (parent.left === node || parent.init === node)) {
+    if (t.isFor(parent) && parent.left === node) {
       return node.declarations[0].id;
     }
 
@@ -78,6 +77,7 @@ export default class SystemFormatter extends AMDFormatter {
   constructor(file) {
     super(file);
 
+    this._setters = null;
     this.exportIdentifier = file.scope.generateUidIdentifier("export");
     this.noInteropRequireExport = true;
     this.noInteropRequireImport = true;
@@ -178,11 +178,14 @@ export default class SystemFormatter extends AMDFormatter {
 
     var block = t.blockStatement(program.body);
 
+    var setterListNode = this._buildRunnerSetters(block, hoistDeclarators);
+    this._setters = setterListNode;
+
     var runner = util.template("system", {
       MODULE_DEPENDENCIES: t.arrayExpression(this.buildDependencyLiterals()),
       EXPORT_IDENTIFIER:   this.exportIdentifier,
       MODULE_NAME:         moduleNameLiteral,
-      SETTERS:             this._buildRunnerSetters(block, hoistDeclarators),
+      SETTERS:             setterListNode,
       EXECUTE:             t.functionExpression(null, [], block)
     }, true);
 

src/babel/transformation/templates/default-parameter.js

@@ -1 +1 @@
-let VARIABLE_NAME = ARGUMENTS[ARGUMENT_KEY] === undefined ? DEFAULT_VALUE : ARGUMENTS[ARGUMENT_KEY];
+let VARIABLE_NAME = ARGUMENTS.length <= ARGUMENT_KEY || ARGUMENTS[ARGUMENT_KEY] === undefined ? DEFAULT_VALUE : ARGUMENTS[ARGUMENT_KEY];

src/babel/transformation/templates/helper-create-decorated-object.js

@@ -13,7 +13,7 @@
 
     descriptor.enumerable = true;
     descriptor.configurable = true;
-    descriptor.writable = true;
+    if ("value" in descriptor || descriptor.initializer) descriptor.writable = true;
 
     if (decorators) {
       for (var f = 0; f < decorators.length; f++) {

src/babel/transformation/templates/helper-define-property.js

@@ -1,8 +1,18 @@
 (function (obj, key, value) {
-  return Object.defineProperty(obj, key, {
-    value: value,
-    enumerable: true,
-    configurable: true,
-    writable: true
-  });
+  // Shortcircuit the slow defineProperty path when possible.
+  // We are trying to avoid issues where setters defined on the
+  // prototype cause side effects under the fast path of simple
+  // assignment. By checking for existence of the property with
+  // the in operator, we can optimize most of this overhead away.
+  if (key in obj) {
+    Object.defineProperty(obj, key, {
+      value: value,
+      enumerable: true,
+      configurable: true,
+      writable: true
+    });
+  } else {
+    obj[key] = value;
+  }
+  return obj;
 });

src/babel/transformation/templates/helper-sliced-to-array.js

@@ -1,7 +1,7 @@
-(function (arr, i) {
-  if (Array.isArray(arr)) {
-    return arr;
-  } else if (Symbol.iterator in Object(arr)) {
+(function () {
+  // Broken out into a separate function to avoid deoptimizations due to the try/catch for the
+  // array iterator case.
+  function sliceIterator(arr, i) {
     // this is an expanded form of `for...of` that properly supports abrupt completions of
     // iterators etc. variable names have been minimised to reduce the size of this massive
     // helper. sometimes spec compliancy is annoying :(
@@ -32,7 +32,15 @@
       }
     }
     return _arr;
-  } else {
-    throw new TypeError("Invalid attempt to destructure non-iterable instance");
   }
-});
+
+  return function (arr, i) {
+    if (Array.isArray(arr)) {
+      return arr;
+    } else if (Symbol.iterator in Object(arr)) {
+      return sliceIterator(arr, i);
+    } else {
+      throw new TypeError("Invalid attempt to destructure non-iterable instance");
+    }
+  };
+})();

src/babel/transformation/transformers/deprecated.json

@@ -8,5 +8,8 @@
   "utility.inlineExpressions": "minification.constantFolding",
   "utility.deadCodeElimination": "minification.deadCodeElimination",
   "utility.removeConsoleCalls": "minification.removeConsole",
-  "utility.removeDebugger": "minification.removeDebugger"
+  "utility.removeDebugger": "minification.removeDebugger",
+
+  "es6.parameters.rest": "es6.parameters",
+  "es6.parameters.default": "es6.parameters"
 }

src/babel/transformation/transformers/es6/block-scoping.js

@@ -162,6 +162,7 @@ var hoistVarDeclarationsVisitor = {
     } else if (this.isFor()) {
       if (isVar(node.left, node)) {
         node.left = node.left.declarations[0].id;
+        self.pushDeclar(node.left);
       }
     } else if (isVar(node, parent)) {
       return self.pushDeclar(node).map(t.expressionStatement);

src/babel/transformation/transformers/es6/classes/index.js

@@ -0,0 +1,23 @@
+import LooseTransformer from "./loose";
+import VanillaTransformer from "./vanilla";
+import * as t from "../../../../types";
+import { bare } from "../../../helpers/name-method";
+
+export var visitor = {
+  ClassDeclaration(node) {
+    return t.variableDeclaration("let", [
+      t.variableDeclarator(node.id, t.toExpression(node))
+    ]);
+  },
+
+  ClassExpression(node, parent, scope, file) {
+    var inferred = bare(node, parent, scope);
+    if (inferred) return inferred;
+
+    if (file.isLoose("es6.classes")) {
+      return new LooseTransformer(this, file).run();
+    } else {
+      return new VanillaTransformer(this, file).run();
+    }
+  }
+};

src/babel/transformation/transformers/es6/classes/loose.js

@@ -0,0 +1,24 @@
+import VanillaTransformer from "./vanilla";
+import * as t from "../../../../types";
+
+export default class LooseClassTransformer extends VanillaTransformer {
+  constructor() {
+    super(...arguments);
+    this.isLoose = true;
+  }
+
+  _processMethod(node) {
+    if (!node.decorators) {
+      // use assignments instead of define properties for loose classes
+
+      var classRef = this.classRef;
+      if (!node.static) classRef = t.memberExpression(classRef, t.identifier("prototype"));
+      var methodName = t.memberExpression(classRef, node.key, node.computed || t.isLiteral(node.key));
+
+      var expr = t.expressionStatement(t.assignmentExpression("=", methodName, node.value));
+      t.inheritsComments(expr, node);
+      this.body.push(expr);
+      return true;
+    }
+  }
+}

src/babel/transformation/transformers/es6/classes/vanilla.js

@@ -1,27 +1,15 @@
-import type NodePath from "../../../traversal/path";
-import type File from "../../file";
-import memoiseDecorators from "../../helpers/memoise-decorators";
-import ReplaceSupers from "../../helpers/replace-supers";
-import * as nameMethod from "../../helpers/name-method";
-import * as defineMap from "../../helpers/define-map";
-import * as messages from "../../../messages";
-import * as util from  "../../../util";
-import * as t from "../../../types";
+import type NodePath from "../../../../traversal/path";
+import type File from "../../../file";
+import memoiseDecorators from "../../../helpers/memoise-decorators";
+import ReplaceSupers from "../../../helpers/replace-supers";
+import * as nameMethod from "../../../helpers/name-method";
+import * as defineMap from "../../../helpers/define-map";
+import * as messages from "../../../../messages";
+import * as util from  "../../../../util";
+import * as t from "../../../../types";
 
 const PROPERTY_COLLISION_METHOD_NAME = "__initializeProperties";
 
-export var visitor = {
-  ClassDeclaration(node) {
-    return t.variableDeclaration("let", [
-      t.variableDeclarator(node.id, t.toExpression(node))
-    ]);
-  },
-
-  ClassExpression(node, parent, scope, file) {
-    return new ClassTransformer(this, file).run();
-  }
-};
-
 var collectPropertyReferencesVisitor = {
   Identifier: {
     enter(node, parent, scope, state) {
@@ -37,16 +25,12 @@ var collectPropertyReferencesVisitor = {
 };
 
 var verifyConstructorVisitor = {
-  MethodDefinition: {
-    enter() {
-      this.skip();
-    }
+  MethodDefinition() {
+    this.skip();
   },
 
-  Property: {
-    enter(node) {
-      if (node.method) this.skip();
-    }
+  Property(node) {
+    if (node.method) this.skip();
   },
 
   CallExpression: {
@@ -55,35 +39,45 @@ var verifyConstructorVisitor = {
         state.hasBareSuper = true;
         state.bareSuper = this;
 
-        if (!state.hasSuper) {
+        if (!state.isDerived) {
           throw this.errorWithNode("super call is only allowed in derived constructor");
         }
       }
     }
   },
 
-  FunctionDeclaration: {
-    enter() {
-      this.skip();
-    }
+  "FunctionDeclaration|FunctionExpression"() {
+    this.skip();
   },
 
-  FunctionExpression: {
-    enter() {
-      this.skip();
-    }
-  },
+  ThisExpression(node, parent, scope, state) {
+    if (state.isDerived && !state.hasBareSuper) {
+      if (this.inShadow()) {
+        // https://github.com/babel/babel/issues/1920
+        var thisAlias = state.constructorPath.getData("this");
 
-  ThisExpression: {
-    enter(node, parent, scope, state) {
-      if (state.hasSuper && !state.hasBareSuper) {
+        if (!thisAlias) {
+          thisAlias = state.constructorPath.setData(
+            "this",
+            state.constructorPath.scope.generateUidIdentifier("this")
+          );
+        }
+
+        return thisAlias;
+      } else {
         throw this.errorWithNode("'this' is not allowed before super()");
       }
     }
+  },
+
+  Super(node, parent, scope, state) {
+    if (state.isDerived && !state.hasBareSuper && !this.parentPath.isCallExpression({ callee: node })) {
+      throw this.errorWithNode("'super.*' is not allowed before super()");
+    }
   }
 };
 
-class ClassTransformer {
+export default class ClassTransformer {
 
   /**
    * Description
@@ -96,26 +90,29 @@ class ClassTransformer {
     this.path   = path;
     this.file   = file;
 
-    this.hasInstanceDescriptors = false;
-    this.hasStaticDescriptors   = false;
-
-    this.instanceMutatorMap = {};
-    this.staticMutatorMap   = {};
+    this.clearDescriptors();
 
     this.instancePropBody = [];
     this.instancePropRefs = {};
     this.staticPropBody   = [];
     this.body             = [];
 
-    this.hasConstructor = false;
-    this.hasDecorators  = false;
-    this.className      = this.node.id;
-    this.classRef       = this.node.id || this.scope.generateUidIdentifier("class");
+    this.pushedConstructor = false;
+    this.pushedInherits    = false;
+    this.hasDecorators     = false;
+    this.isLoose           = false;
+
+    // class id
+    this.classId = this.node.id;
+
+    // this is the name of the binding that will **always** reference the class we've constructed
+    this.classRef = this.node.id || this.scope.generateUidIdentifier("class");
+
+    // this is a direct reference to the class we're building, class decorators can shadow the classRef
+    this.directRef = null;
 
     this.superName = this.node.superClass || t.identifier("Function");
-    this.hasSuper  = !!this.node.superClass;
-
-    this.isLoose = file.isLoose("es6.classes");
+    this.isDerived = !!this.node.superClass;
   }
 
   /**
@@ -126,7 +123,6 @@ class ClassTransformer {
 
   run() {
     var superName = this.superName;
-    var classRef  = this.classRef;
     var file      = this.file;
 
     //
@@ -136,16 +132,7 @@ class ClassTransformer {
     //
 
     var constructorBody = this.constructorBody = t.blockStatement([]);
-    var constructor;
-
-    if (this.className) {
-      constructor = t.functionDeclaration(this.className, [], constructorBody);
-      body.push(constructor);
-    } else {
-      constructor = t.functionExpression(null, [], constructorBody);
-    }
-
-    this.constructor = constructor;
+    this.constructor    = this.buildConstructor();
 
     //
 
@@ -153,26 +140,22 @@ class ClassTransformer {
     var closureArgs = [];
 
     //
-    if (this.hasSuper) {
+    if (this.isDerived) {
       closureArgs.push(superName);
 
       superName = this.scope.generateUidIdentifierBasedOnNode(superName);
       closureParams.push(superName);
 
       this.superName = superName;
-      body.push(t.expressionStatement(t.callExpression(file.addHelper("inherits"), [classRef, superName])));
     }
 
     //
     var decorators = this.node.decorators;
     if (decorators) {
-      // create a class reference to use later on
-      this.classRef = this.scope.generateUidIdentifier(classRef);
-
       // this is so super calls and the decorators have access to the raw function
-      body.push(t.variableDeclaration("var", [
-        t.variableDeclarator(this.classRef, classRef)
-      ]));
+      this.directRef = this.scope.generateUidIdentifier(this.classRef);
+    } else {
+      this.directRef = this.classRef;
     }
 
     //
@@ -181,46 +164,21 @@ class ClassTransformer {
     // make sure this class isn't directly called
     constructorBody.body.unshift(t.expressionStatement(t.callExpression(file.addHelper("class-call-check"), [
       t.thisExpression(),
-      this.classRef
+      this.directRef
     ])));
 
     //
-
-    if (decorators) {
-      // reverse the decorators so we execute them in the right order
-      decorators = decorators.reverse();
-
-      for (var i = 0; i < decorators.length; i++) {
-        var decorator = decorators[i];
-
-        var decoratorNode = util.template("class-decorator", {
-          DECORATOR: decorator.expression,
-          CLASS_REF: classRef
-        }, true);
-        decoratorNode.expression._ignoreModulesRemap = true;
-        body.push(decoratorNode);
-      }
-    }
+    this.pushDecorators();
 
     body = body.concat(this.staticPropBody);
 
-    if (this.className) {
+    if (this.classId) {
       // named class with only a constructor
       if (body.length === 1) return t.toExpression(body[0]);
-    } else {
-      // infer class name if this is a nameless class expression
-      constructor = nameMethod.bare(constructor, this.parent, this.scope) || constructor;
-
-      body.unshift(t.variableDeclaration("var", [
-        t.variableDeclarator(classRef, constructor)
-      ]));
-
-      t.inheritsComments(body[0], this.node);
     }
 
     //
-
-    body.push(t.returnStatement(classRef));
+    body.push(t.returnStatement(this.classRef));
 
     return t.callExpression(
       t.functionExpression(null, closureParams, t.blockStatement(body)),
@@ -228,6 +186,14 @@ class ClassTransformer {
     );
   }
 
+  /**
+   * Description
+   */
+
+  buildConstructor() {
+    return t.functionDeclaration(this.classRef, [], this.constructorBody);
+  }
+
   /**
    * Description
    */
@@ -258,23 +224,26 @@ class ClassTransformer {
    */
 
   constructorMeMaybe() {
-    if (!this.hasSuper) return;
-
     var hasConstructor = false;
     var paths = this.path.get("body.body");
-
     for (var path of (paths: Array)) {
       hasConstructor = path.equals("kind", "constructor");
       if (hasConstructor) break;
     }
+    if (hasConstructor) return;
 
-    if (!hasConstructor) {
-      this.path.get("body").unshiftContainer("body", t.methodDefinition(
-        t.identifier("constructor"),
-        util.template("class-derived-default-constructor"),
-        "constructor"
-      ));
+    var constructor;
+    if (this.isDerived) {
+      constructor = util.template("class-derived-default-constructor");
+    } else {
+      constructor = t.functionExpression(null, [], t.blockStatement([]));
     }
+
+    this.path.get("body").unshiftContainer("body", t.methodDefinition(
+      t.identifier("constructor"),
+      constructor,
+      "constructor"
+    ));
   }
 
   /**
@@ -283,10 +252,25 @@ class ClassTransformer {
 
   buildBody() {
     this.constructorMeMaybe();
+    this.pushBody();
+    this.placePropertyInitializers();
 
-    var constructorBody = this.constructorBody;
-    var classBodyPaths  = this.path.get("body.body");
-    var body            = this.body;
+    if (this.userConstructor) {
+      var constructorBody = this.constructorBody;
+      constructorBody.body = constructorBody.body.concat(this.userConstructor.body.body);
+      t.inherits(this.constructor, this.userConstructor);
+      t.inherits(constructorBody, this.userConstructor.body);
+    }
+
+    this.pushDescriptors();
+  }
+
+  /**
+   * Description
+   */
+
+  pushBody() {
+    var classBodyPaths = this.path.get("body.body");
 
     for (var path of (classBodyPaths: Array)) {
       var node = path.node;
@@ -302,7 +286,7 @@ class ClassTransformer {
         var replaceSupers = new ReplaceSupers({
           methodPath: path,
           methodNode: node,
-          objectRef:  this.classRef,
+          objectRef:  this.directRef,
           superRef:   this.superName,
           isStatic:   node.static,
           isLoose:    this.isLoose,
@@ -321,16 +305,28 @@ class ClassTransformer {
         this.pushProperty(node, path);
       }
     }
+  }
 
-    //
-    this.placePropertyInitializers();
+  /**
+   * Description
+   */
 
-    //
-    if (this.userConstructor) {
-      constructorBody.body = constructorBody.body.concat(this.userConstructor.body.body);
-      t.inherits(this.constructor, this.userConstructor);
-      t.inherits(this.constructorBody, this.userConstructor.body);
-    }
+  clearDescriptors() {
+    this.hasInstanceDescriptors = false;
+    this.hasStaticDescriptors   = false;
+
+    this.instanceMutatorMap = {};
+    this.staticMutatorMap   = {};
+  }
+
+  /**
+   * Description
+   */
+
+  pushDescriptors() {
+    this.pushInherits();
+
+    var body = this.body;
 
     var instanceProps;
     var staticProps;
@@ -378,8 +374,14 @@ class ClassTransformer {
         t.callExpression(this.file.addHelper(classHelper), args)
       ));
     }
+
+    this.clearDescriptors();
   }
 
+  /**
+   * Description
+   */
+
   buildObjectAssignment(id) {
     return t.variableDeclaration("var", [
       t.variableDeclarator(id, t.objectExpression([]))
@@ -405,18 +407,14 @@ class ClassTransformer {
         t.functionExpression(null, [], t.blockStatement(body))
       ), null, true);
 
-      if (this.hasSuper) {
+      if (this.isDerived) {
         this.bareSuper.insertAfter(call);
       } else {
         this.constructorBody.body.unshift(call);
       }
     } else {
-      if (this.hasSuper) {
-        if (this.hasConstructor) {
-          this.bareSuper.insertAfter(body);
-        } else {
-          this.constructorBody.body = this.constructorBody.body.concat(body);
-        }
+      if (this.isDerived) {
+        this.bareSuper.insertAfter(body);
       } else {
         this.constructorBody.body = body.concat(this.constructorBody.body);
       }
@@ -437,7 +435,7 @@ class ClassTransformer {
     }
 
     return false;
-   }
+  }
 
   /**
    * Description
@@ -445,17 +443,25 @@ class ClassTransformer {
 
    verifyConstructor(path: NodePath) {
     var state = {
-      hasBareSuper: false,
-      bareSuper:    null,
-      hasSuper:     this.hasSuper,
-      file:         this.file
+      constructorPath: path.get("value"),
+      hasBareSuper:    false,
+      bareSuper:       null,
+      isDerived:       this.isDerived,
+      file:            this.file,
     };
 
-    path.get("value").traverse(verifyConstructorVisitor, state);
+    state.constructorPath.traverse(verifyConstructorVisitor, state);
+
+    var thisAlias = state.constructorPath.getData("this");
+    if (thisAlias && state.bareSuper) {
+      state.bareSuper.insertAfter(t.variableDeclaration("var", [
+        t.variableDeclarator(thisAlias, t.thisExpression())
+      ]));
+    }
 
     this.bareSuper = state.bareSuper;
 
-    if (!state.hasBareSuper && this.hasSuper) {
+    if (!state.hasBareSuper && this.isDerived) {
       throw path.errorWithNode("Derived constructor must call super()");
     }
   }
@@ -471,24 +477,16 @@ class ClassTransformer {
 
     if (node.kind === "method") {
       nameMethod.property(node, this.file, path ? path.get("value").scope : this.scope);
-
-      if (this.isLoose && !node.decorators) {
-        // use assignments instead of define properties for loose classes
-
-        var classRef = this.classRef;
-        if (!node.static) classRef = t.memberExpression(classRef, t.identifier("prototype"));
-        var methodName = t.memberExpression(classRef, node.key, node.computed || t.isLiteral(node.key));
-
-        var expr = t.expressionStatement(t.assignmentExpression("=", methodName, node.value));
-        t.inheritsComments(expr, node);
-        this.body.push(expr);
-        return;
-      }
+      if (this._processMethod(node)) return;
     }
 
     this.pushToMap(node);
   }
 
+  _processMethod() {
+    return false;
+  }
+
   /**
    * Description
    */
@@ -568,5 +566,61 @@ class ClassTransformer {
     construct.params                = fn.params;
 
     t.inherits(construct.body, fn.body);
+
+    // push constructor to body
+    this._pushConstructor();
+  }
+
+  _pushConstructor() {
+    if (this.pushedConstructor) return;
+    this.pushedConstructor = true;
+
+    // we haven't pushed any descriptors yet
+    if (this.hasInstanceDescriptors || this.hasStaticDescriptors) {
+      this.pushDescriptors();
+    }
+
+    this.body.push(this.constructor);
+
+    this.pushInherits();
+  }
+
+  /**
+   * Push inherits helper to body.
+   */
+
+  pushInherits() {
+    if (!this.isDerived || this.pushedInherits) return;
+
+    this.pushedInherits = true;
+    this.body.push(t.expressionStatement(t.callExpression(
+      this.file.addHelper("inherits"),
+      [this.classRef, this.superName]
+    )));
+  }
+
+  /**
+   * Push decorators to body.
+   */
+
+  pushDecorators() {
+    var decorators = this.node.decorators;
+    if (!decorators) return;
+
+    this.body.push(t.variableDeclaration("var", [
+      t.variableDeclarator(this.directRef, this.classRef)
+    ]));
+
+    // reverse the decorators so we execute them in the right order
+    decorators = decorators.reverse();
+
+    for (var decorator of (decorators: Array)) {
+      var decoratorNode = util.template("class-decorator", {
+        DECORATOR: decorator.expression,
+        CLASS_REF: this.classRef
+      }, true);
+      decoratorNode.expression._ignoreModulesRemap = true;
+      this.body.push(decoratorNode);
+    }
   }
 }

src/babel/transformation/transformers/es6/destructuring.js

@@ -70,7 +70,15 @@ export var visitor = {
       let pattern = node.params[i];
       if (!t.isPattern(pattern)) continue;
 
-      var ref = node.params[i] = scope.generateUidIdentifier("ref");
+      var ref = scope.generateUidIdentifier("ref");
+      if (t.isAssignmentPattern(pattern)) {
+        var _pattern = pattern;
+        pattern = pattern.left;
+        _pattern.left = ref;
+      } else {
+        node.params[i] = ref;
+      }
+
       t.inherits(ref, pattern);
 
       var destructuring = new DestructuringTransformer({
@@ -308,9 +316,12 @@ class DestructuringTransformer {
 
     var left = pattern.left;
     if (t.isPattern(left)) {
-      this.nodes.push(t.expressionStatement(
+      var tempValueDefault = t.expressionStatement(
         t.assignmentExpression("=", tempValueRef, tempConditional)
-      ));
+      );
+      tempValueDefault._blockHoist = this.blockHoist;
+
+      this.nodes.push(tempValueDefault);
       this.push(left, tempValueRef);
     } else {
       this.nodes.push(this.buildVariableAssignment(left, tempConditional));

src/babel/transformation/transformers/es6/parameters/default.js

@@ -1,7 +1,7 @@
-import callDelegate from "../../helpers/call-delegate";
-import getFunctionArity from "../../helpers/get-function-arity";
-import * as util from  "../../../util";
-import * as t from "../../../types";
+import callDelegate from "../../../helpers/call-delegate";
+import getFunctionArity from "../../../helpers/get-function-arity";
+import * as util from  "../../../../util";
+import * as t from "../../../../types";
 
 var hasDefaults = function (node) {
   for (var i = 0; i < node.params.length; i++) {
@@ -38,7 +38,7 @@ export var visitor = {
 
     //
     var argsIdentifier = t.identifier("arguments");
-    argsIdentifier._shadowedFunctionLiteral = true;
+    argsIdentifier._shadowedFunctionLiteral = this;
 
     // push a default parameter definition
     function pushDefNode(left, right, i) {

src/babel/transformation/transformers/es6/parameters/index.js

@@ -0,0 +1,10 @@
+import * as visitors from "../../../../traversal/visitors";
+
+import * as def from "./default";
+import * as rest from "./rest";
+
+export var metadata = {
+  group: "builtin-advanced"
+};
+
+export var visitor = visitors.merge([rest.visitor, def.visitor]);

src/babel/transformation/transformers/es6/parameters/rest.js

@@ -1,5 +1,5 @@
-import * as util from  "../../../util";
-import * as t from "../../../types";
+import * as util from  "../../../../util";
+import * as t from "../../../../types";
 
 var memberExpressionOptimisationVisitor = {
   Scope(node, parent, scope, state) {
@@ -9,12 +9,18 @@ var memberExpressionOptimisationVisitor = {
     }
   },
 
+  Flow() {
+    // don't touch reference in type annotations
+    this.skip();
+  },
+
   Function(node, parent, scope, state) {
     // skip over functions as whatever `arguments` we reference inside will refer
     // to the wrong function
+    var oldNoOptimise = state.noOptimise;
     state.noOptimise = true;
     this.traverse(memberExpressionOptimisationVisitor, state);
-    state.noOptimise = false;
+    state.noOptimise = oldNoOptimise;
     this.skip();
   },
 
@@ -27,7 +33,9 @@ var memberExpressionOptimisationVisitor = {
     // is this a referenced identifier and is it referencing the rest parameter?
     if (node.name !== state.name) return;
 
-    if (!state.noOptimise) {
+    if (state.noOptimise) {
+      state.deopted = true;
+    } else {
       if (this.parentPath.isMemberExpression({ computed: true, object: node })) {
         // if we know that this member expression is referencing a number then we can safely
         // optimise it
@@ -46,11 +54,7 @@ var memberExpressionOptimisationVisitor = {
           return;
         }
       }
-    }
 
-    if (state.noOptimise) {
-      state.deopted = true;
-    } else {
       state.references.push(this);
     }
   }
@@ -85,7 +89,7 @@ export var visitor = {
     var argsId = t.identifier("arguments");
 
     // otherwise `arguments` will be remapped in arrow functions
-    argsId._shadowedFunctionLiteral = true;
+    argsId._shadowedFunctionLiteral = this;
 
     // support patterns
     if (t.isPattern(rest)) {
@@ -100,7 +104,6 @@ export var visitor = {
     }
 
     // check and optimise for extremely common cases
-
     var state = {
       references: [],
       offset:     node.params.length,
@@ -135,6 +138,9 @@ export var visitor = {
       state.references = state.references.concat(state.candidates);
     }
 
+    // deopt shadowed functions as transforms like regenerator may try touch the allocation loop
+    state.deopted = state.deopted || !!node.shadow;
+
     //
 
     var start = t.literal(node.params.length);
@@ -173,13 +179,13 @@ export var visitor = {
       LEN:        len
     });
 
-    if (!state.deopted) {
+    if (state.deopted) {
+      loop._blockHoist = node.params.length + 1;
+      node.body.body.unshift(loop);
+    } else {
       // perform allocation at the lowest common denominator of all references
+      loop._blockHoist = 1;
       this.getEarliestCommonAncestorFrom(state.references).getStatementParent().insertBefore(loop);
-      return;
     }
-
-    loop._blockHoist = node.params.length + 1;
-    node.body.body.unshift(loop);
   }
 };

src/babel/transformation/transformers/es6/properties.computed.js

@@ -1,9 +1,7 @@
 import * as t from "../../../types";
 
 function loose(node, body, objId) {
-  for (var i = 0; i < node.properties.length; i++) {
-    var prop = node.properties[i];
-
+  for (var prop of (node.properties: Array)) {
     body.push(t.expressionStatement(
       t.assignmentExpression(
         "=",
@@ -15,31 +13,15 @@ function loose(node, body, objId) {
 }
 
 function spec(node, body, objId, initProps, file) {
-  var props = node.properties;
-
-  // add all non-computed properties and `__proto__` properties to the initializer
-
-  var broken = false;
-
-  for (let i = 0; i < props.length; i++) {
-    let prop = props[i];
-
-    if (prop.computed) {
-      broken = true;
-    }
-
-    if (prop.kind !== "init" || !broken || t.isLiteral(t.toComputedKey(prop, prop.key), { value: "__proto__" })) {
-      initProps.push(prop);
-      props[i] = null;
-    }
-  }
-
   // add a simple assignment for all Symbol member expressions due to symbol polyfill limitations
   // otherwise use Object.defineProperty
 
-  for (let i = 0; i < props.length; i++) {
-    let prop = props[i];
-    if (!prop) continue;
+  for (let prop of (node.properties: Array)) {
+    // this wont work with Object.defineProperty
+    if (t.isLiteral(t.toComputedKey(prop), { value: "__proto__" })) {
+      initProps.push(prop);
+      continue;
+    }
 
     let key = prop.key;
     if (t.isIdentifier(key) && !prop.computed) {
@@ -68,14 +50,34 @@ export var visitor = {
     exit(node, parent, scope, file) {
       var hasComputed = false;
 
-      for (var prop of (node.properties: Array)) {
+      for (let prop of (node.properties: Array)) {
         hasComputed = t.isProperty(prop, { computed: true, kind: "init" });
         if (hasComputed) break;
       }
 
       if (!hasComputed) return;
 
+      // put all getters/setters into the first object expression as well as all initialisers up
+      // to the first computed property
+
       var initProps = [];
+      var stopInits = false;
+
+      node.properties = node.properties.filter(function (prop) {
+        if (prop.computed) {
+          stopInits = true;
+        }
+
+        if (prop.kind !== "init" || !stopInits) {
+          initProps.push(prop);
+          return false;
+        } else {
+          return true;
+        }
+      });
+
+      //
+
       var objId = scope.generateUidIdentifierBasedOnNode(parent);
 
       //

src/babel/transformation/transformers/es6/spread.js

@@ -43,6 +43,10 @@ function build(props, scope) {
   return nodes;
 }
 
+export var metadata = {
+  group: "builtin-advanced"
+};
+
 export var visitor = {
   ArrayExpression(node, parent, scope) {
     var elements = node.elements;

src/babel/transformation/transformers/es6/tail-call.js

@@ -211,7 +211,7 @@ class TailCallTransformer {
       var decl = t.variableDeclarator(this.argumentsId);
       if (this.argumentsId) {
         decl.init = t.identifier("arguments");
-        decl.init._shadowedFunctionLiteral = true;
+        decl.init._shadowedFunctionLiteral = this.path;
       }
       topVars.push(decl);
     }
@@ -337,10 +337,6 @@ class TailCallTransformer {
       args = t.arrayExpression(node.arguments);
     }
 
-    if (t.isArrayExpression(args) && args.elements.length > this.node.params.length) {
-      this.needsArguments = true;
-    }
-
     var argumentsId = this.getArgumentsId();
     var params      = this.getParams();
 
@@ -354,17 +350,30 @@ class TailCallTransformer {
 
     if (t.isArrayExpression(args)) {
       var elems = args.elements;
-      for (let i = 0; i < elems.length && i < params.length; i++) {
+
+      // pad out the args so all the function args are reset - https://github.com/babel/babel/issues/1938
+      while (elems.length < params.length) {
+        elems.push(t.identifier("undefined"));
+      }
+
+      for (let i = 0; i < elems.length; i++) {
         let param = params[i];
-        let elem = elems[i] || (elems[i] = t.identifier("undefined"));
-        if (!param._isDefaultPlaceholder) {
+        let elem  = elems[i];
+
+        if (param && !param._isDefaultPlaceholder) {
           elems[i] = t.assignmentExpression("=", param, elem);
+        } else {
+          // exceeds parameters but push it anyway to ensure correct execution
         }
       }
 
       if (!this.needsArguments) {
         for (let elem of (elems: Array)) {
-          body.push(t.expressionStatement(elem));
+          // only push expressions that we really need, this will skip pure arguments that exceed the
+          // parameter length of the current function
+          if (!this.scope.isPure(elem)) {
+            body.push(t.expressionStatement(elem));
+          }
         }
       }
     } else {

src/babel/transformation/transformers/es6/template-literals.js

@@ -60,20 +60,16 @@ export var visitor = {
       if (expr) nodes.push(expr);
     }
 
+    // filter out empty string literals
+    nodes = nodes.filter(n => !t.isLiteral(n, { value: "" }));
+
+    // since `+` is left-to-right associative
+    // ensure the first node is a string if first/second isn't
+    if (!isString(nodes[0]) && !isString(nodes[1])) {
+      nodes.unshift(t.literal(""));
+    }
+
     if (nodes.length > 1) {
-      // filter out empty string literals
-      nodes = nodes.filter(n => !t.isLiteral(n, { value: "" }));
-
-      if (nodes.length === 1 && isString(nodes[0])) {
-        return nodes[0];
-      }
-
-      // since `+` is left-to-right associative
-      // ensure the first node is a string if first/second isn't
-      if (!isString(nodes[0]) && !isString(nodes[1])) {
-        nodes.unshift(t.literal(""));
-      }
-
       var root = buildBinaryExpression(nodes.shift(), nodes.shift());
 
       for (let node of (nodes: Array)) {

src/babel/transformation/transformers/index.js

@@ -46,9 +46,6 @@ export default {
   "es6.regex.sticky":                      require("./es6/regex.sticky"),
   "es6.regex.unicode":                     require("./es6/regex.unicode"),
   "es6.constants":                         require("./es6/constants"),
-  "es6.parameters.rest":                   require("./es6/parameters.rest"),
-  "es6.spread":                            require("./es6/spread"),
-  "es6.parameters.default":                require("./es6/parameters.default"),
   "es7.exportExtensions":                  require("./es7/export-extensions"),
   "spec.protoToAssign":                    require("babel-plugin-proto-to-assign"),
   "es7.doExpressions":                     require("./es7/do-expressions"),
@@ -57,6 +54,8 @@ export default {
   "spec.undefinedToVoid":                  require("babel-plugin-undefined-to-void"),
 
   //- builtin-advanced
+  "es6.spread":                            require("./es6/spread"),
+  "es6.parameters":                        require("./es6/parameters"),
   "es6.destructuring":                     require("./es6/destructuring"),
   "es6.blockScoping":                      require("./es6/block-scoping"),
   "es6.spec.blockScoping":                 require("./es6/spec.block-scoping"),
@@ -85,4 +84,5 @@ export default {
   _blockHoist:                             require("./internal/block-hoist"),
   jscript:                                 require("babel-plugin-jscript"),
   flow:                                    require("./other/flow"),
+  "optimisation.modules.system":           require("./optimisation/modules.system"),
 };

src/babel/transformation/transformers/internal/shadow-functions.js

@@ -6,9 +6,33 @@ export var metadata = {
 
 function remap(path, key, create) {
   // ensure that we're shadowed
-  if (!path.inShadow()) return;
+  var shadowPath = path.inShadow();
+  if (!shadowPath || shadowPath.isArrowFunctionExpression()) return;
 
-  var fnPath = path.findParent((path) => !path.is("shadow") && (path.isFunction() || path.isProgram()));
+  var shadowFunction = path.node._shadowedFunctionLiteral;
+  var currentFunction;
+
+  var fnPath = path.findParent(function (path) {
+    if (path.isProgram() || path.isFunction()) {
+      // catch current function in case this is the shadowed one and we can ignore it
+      currentFunction = currentFunction || path;
+    }
+
+    if (path.isProgram()) {
+      return true;
+    } else if (path.isFunction()) {
+      if (shadowFunction) {
+        return path === shadowFunction || path.node === shadowFunction.node;
+      } else {
+        return !path.is("shadow");
+      }
+    }
+
+    return false;
+  });
+
+  // no point in realiasing if we're in this function
+  if (fnPath === currentFunction) return;
 
   var cached = fnPath.getData(key);
   if (cached) return cached;
@@ -28,7 +52,7 @@ export var visitor = {
   },
 
   ReferencedIdentifier(node) {
-    if (node.name === "arguments" && !node._shadowedFunctionLiteral) {
+    if (node.name === "arguments") {
       return remap(this, "arguments", () => t.identifier("arguments"));
     }
   }

src/babel/transformation/transformers/optimisation/modules.system.js

@@ -0,0 +1,50 @@
+import * as t from "../../../types";
+
+export var metadata = {
+  optional: true,
+  group: "builtin-trailing"
+};
+
+export var visitor = {
+  Program(node, parent, scope, file){
+    if (file.moduleFormatter._setters){
+      scope.traverse(file.moduleFormatter._setters, optimizeSettersVisitor, {
+        exportFunctionIdentifier: file.moduleFormatter.exportIdentifier
+      });
+    }
+  }
+};
+
+/**
+ * Setters are optimized to avoid slow export behavior in modules that rely on deep hierarchies
+ * of export-from declarations.
+ * More info in https://github.com/babel/babel/pull/1722 and
+ * https://github.com/ModuleLoader/es6-module-loader/issues/386.
+ *
+ * TODO: Ideally this would be optimized during construction of the setters, but the current
+ * architecture of the module formatters make that difficult.
+ */
+var optimizeSettersVisitor = {
+  FunctionExpression: {
+    enter: (node, parent, scope, state) => {
+      state.hasExports = false;
+      state.exportObjectIdentifier = scope.generateUidIdentifier("exportObj");
+    },
+    exit: (node, parent, scope, state) => {
+      if (!state.hasExports) return;
+
+      node.body.body.unshift(t.variableDeclaration("var", [
+        t.variableDeclarator(t.cloneDeep(state.exportObjectIdentifier), t.objectExpression([]))
+      ]));
+      node.body.body.push(t.expressionStatement(t.callExpression(
+        t.cloneDeep(state.exportFunctionIdentifier), [t.cloneDeep(state.exportObjectIdentifier)])));
+    }
+  },
+  CallExpression: (node, parent, scope, state) => {
+    if (!t.isIdentifier(node.callee, {name: state.exportFunctionIdentifier.name})) return;
+
+    state.hasExports = true;
+    var memberNode = t.memberExpression(t.cloneDeep(state.exportObjectIdentifier), node.arguments[0], true);
+    return t.assignmentExpression("=", memberNode, node.arguments[1]);
+  }
+};

src/babel/transformation/transformers/optimisation/react.inline-elements.js

@@ -49,7 +49,9 @@ export var visitor = {
     pushElemProp("ref", t.literal(null));
 
     if (node.children.length) {
-      pushProp(props.properties, t.identifier("children"), t.arrayExpression(react.buildChildren(node)));
+      var children = react.buildChildren(node);
+      children = children.length === 1 ? children[0] : t.arrayExpression(children);
+      pushProp(props.properties, t.identifier("children"), children);
     }
 
     // props

src/babel/transformation/transformers/other/flow.js

@@ -5,6 +5,14 @@ export var metadata = {
 };
 
 export var visitor = {
+  Program(node, parent, scope, file) {
+    for (var comment of (file.ast.comments: Array)) {
+      if (comment.value.indexOf("@flow") >= 0) {
+        comment._displayed = true;
+      }
+    }
+  },
+
   Flow() {
     this.dangerouslyRemove();
   },

src/babel/transformation/transformers/spec/function-name.js

@@ -4,8 +4,24 @@ export var metadata = {
   group: "builtin-basic"
 };
 
+// visit Property functions first - https://github.com/babel/babel/issues/1860
 export var visitor = {
   "ArrowFunctionExpression|FunctionExpression": {
-    exit: bare
+    exit() {
+      if (!this.parentPath.isProperty()) {
+        return bare.apply(this, arguments);
+      }
+    }
+  },
+
+  ObjectExpression() {
+    var props = this.get("properties");
+    for (var prop of (props: Array)) {
+      var value = prop.get("value");
+      if (value.isFunction()) {
+        var newNode = bare(value.node, prop.node, value.scope);
+        if (newNode) value.replaceWith(newNode);
+      }
+    }
   }
 };

src/babel/traversal/path/ancestry.js

@@ -2,20 +2,28 @@ import * as t from "../../types";
 import NodePath from "./index";
 
 /**
- * Description
+ * Call the provided `callback` with the `NodePath`s of all the parents.
+ * When the `callback` returns a truthy value, we return that node path.
  */
 
 export function findParent(callback) {
   var path = this;
-  while (path) {
+  while (path = path.parentPath) {
     if (callback(path)) return path;
-    path = path.parentPath;
   }
   return null;
 }
 
 /**
- * Description
+ * Get the parent function of the current path.
+ */
+
+export function getFunctionParent() {
+  return this.findParent((path) => path.isFunction() || path.isProgram());
+}
+
+/**
+ * Walk up the tree until we hit a parent node path in a list.
  */
 
 export function getStatementParent() {
@@ -139,7 +147,9 @@ export function getDeepestCommonAncestorFrom(paths: Array<NodePath>, filter?: Fu
 }
 
 /**
- * Description
+ * Build an array of node paths containing the entire ancestry of the current node path.
+ *
+ * NOTE: The current node path is included in this.
  */
 
 export function getAncestry() {
@@ -168,14 +178,14 @@ export function inType() {
 }
 
 /**
- * Description
+ * Check if we're inside a shadowed function.
  */
 
 export function inShadow() {
   var path = this;
   while (path) {
     if (path.isFunction()) {
-      if (path.node.shadow) {
+      if (path.node.shadow || path.isArrowFunctionExpression()) {
         return path;
       } else {
         return null;

src/babel/traversal/path/context.js

@@ -230,6 +230,7 @@ export function unshiftContext(context) {
  */
 
 export function setup(parentPath, container, listKey, key) {
+  this.inList    = !!listKey;
   this.listKey   = listKey;
   this.parentKey = listKey || key;
   this.container = container;

src/babel/traversal/path/family.js

@@ -1,3 +1,4 @@
+import type TraversalContext from "../index";
 import NodePath from "./index";
 import * as t from "../../types";
 
@@ -39,7 +40,7 @@ export function getOpposite() {
  * Description
  */
 
-export function getCompletionRecords(): Array<NodePath> {
+export function getCompletionRecords(): Array {
   var paths = [];
 
   var add = function (path) {
@@ -80,12 +81,13 @@ export function getSibling(key) {
  * Description
  */
 
-export function get(key: string): NodePath {
+export function get(key: string, context?: boolean | TraversalContext): NodePath {
+  if (context === true) context = this.context;
   var parts = key.split(".");
   if (parts.length === 1) { // "foo"
-    return this._getKey(key);
+    return this._getKey(key, context);
   } else { // "foo.bar"
-    return this._getPattern(parts);
+    return this._getPattern(parts, context);
   }
 }
 
@@ -93,7 +95,7 @@ export function get(key: string): NodePath {
  * Description
  */
 
-export function _getKey(key) {
+export function _getKey(key, context?) {
   var node      = this.node;
   var container = node[key];
 
@@ -106,7 +108,7 @@ export function _getKey(key) {
         parent: node,
         container: container,
         key: i
-      }).setContext();
+      }).setContext(context);
     });
   } else {
     return NodePath.get({
@@ -114,7 +116,7 @@ export function _getKey(key) {
       parent: node,
       container: node,
       key: key
-    }).setContext();
+    }).setContext(context);
   }
 }
 
@@ -122,7 +124,7 @@ export function _getKey(key) {
  * Description
  */
 
-export function _getPattern(parts) {
+export function _getPattern(parts, context) {
   var path = this;
   for (var part of (parts: Array)) {
     if (part === ".") {
@@ -131,7 +133,7 @@ export function _getPattern(parts) {
       if (Array.isArray(path)) {
         path = path[part];
       } else {
-        path = path.get(part);
+        path = path.get(part, context);
       }
     }
   }
@@ -142,6 +144,6 @@ export function _getPattern(parts) {
  * Description
  */
 
-export function getBindingIdentifiers() {
-  return t.getBindingIdentifiers(this.node);
+export function getBindingIdentifiers(duplicates?) {
+  return t.getBindingIdentifiers(this.node, duplicates);
 }

src/babel/traversal/path/index.js

@@ -21,6 +21,7 @@ export default class NodePath {
     this.context            = null;
     this.container          = null;
     this.listKey            = null;
+    this.inList             = false;
     this.parentKey          = null;
     this.key                = null;
     this.node               = null;

src/babel/traversal/path/inference/index.js

@@ -1,3 +1,4 @@
+import type NodePath from "./index";
 import * as inferers from "./inferers";
 import * as t from "../../../types";
 
@@ -61,9 +62,11 @@ export function _getTypeAnnotation(): ?Object {
  * Description
  */
 
-export function isBaseType(baseName: string): boolean {
-  var type = this.getTypeAnnotation();
+export function isBaseType(baseName: string, soft?): boolean {
+  return _isBaseType(baseName, this.getTypeAnnotation(), soft);
+}
 
+function _isBaseType(baseName: string, type?, soft?): boolean {
   if (baseName === "string") {
     return t.isStringTypeAnnotation(type);
   } else if (baseName === "number") {
@@ -74,8 +77,47 @@ export function isBaseType(baseName: string): boolean {
     return t.isAnyTypeAnnotation(type);
   } else if (baseName === "mixed") {
     return t.isMixedTypeAnnotation(type);
+  } else if (baseName === "void") {
+    return t.isVoidTypeAnnotation(type);
   } else {
-    throw new Error(`Unknown base type ${baseName}`);
+    if (soft) {
+      return false;
+    } else {
+      throw new Error(`Unknown base type ${baseName}`);
+    }
+  }
+}
+
+/**
+ * Description
+ */
+
+export function couldBeBaseType(name: string): boolean {
+  var type = this.getTypeAnnotation();
+  if (t.isAnyTypeAnnotation(type)) return true;
+
+  if (t.isUnionTypeAnnotation(type)) {
+    for (var type2 of (type.types: Array)) {
+      if (t.isAnyTypeAnnotation(type2) || _isBaseType(name, type2, true)) {
+        return true;
+      }
+    }
+    return false;
+  } else {
+    return _isBaseType(name, type, true);
+  }
+}
+
+/**
+ * Description
+ */
+
+export function baseTypeStrictlyMatches(right: NodePath) {
+  var left = this.getTypeAnnotation();
+  right = right.getTypeAnnotation();
+
+  if (!t.isAnyTypeAnnotation() && t.isFlowBaseAnnotation(left)) {
+    return right.type === left.type;
   }
 }
 

src/babel/traversal/path/inference/inferers.js

@@ -140,7 +140,7 @@ export function ObjectExpression() {
 
 //
 
-export function ArrayExpression () {
+export function ArrayExpression() {
   return t.genericTypeAnnotation(t.identifier("Array"));
 }
 

src/babel/traversal/path/introspection.js

@@ -147,18 +147,6 @@ export function isCompletionRecord(allowInsideFunction?) {
   return true;
 }
 
-/**
- * Description
- */
-
-export function isDirective() {
-  if (this.isExpressionStatement()) {
-    return this.get("expression").isLiteral();
-  } else {
-    return this.isLiteral() && this.parentPath.isExpressionStatement();
-  }
-}
-
 /**
  * Check whether or not the current `key` allows either a single statement or block statement
  * so we can explode it if necessary.
@@ -172,22 +160,6 @@ export function isStatementOrBlock() {
   }
 }
 
-/**
- * Check whether this node was a part of the original AST.
- */
-
-export function isUser() {
-  return this.node && !!this.node.loc;
-}
-
-/**
- * Check whether this node was generated by us and not a part of the original AST.
- */
-
-export function isGenerated() {
-  return !this.isUser();
-}
-
 /**
  * Check if the currently assigned path references the `importName` of `moduleSource`.
  */
@@ -226,7 +198,7 @@ export function referencesImport(moduleSource, importName) {
 }
 
 /**
- * Description
+ * Get the source code associated with this node.
  */
 
 export function getSource() {

src/babel/traversal/path/lib/hoister.js

@@ -19,7 +19,7 @@ var referenceVisitor = {
       state.bindings[node.name] = binding;
     } else {
       for (var violationPath of (binding.constantViolations: Array)) {
-        state.breakOnScopePaths.push(violationPath.scope.path);
+        state.breakOnScopePaths = state.breakOnScopePaths.concat(violationPath.getAncestry());
       }
     }
   }
@@ -106,12 +106,15 @@ export default class PathHoister {
 
     this.getCompatibleScopes();
 
-    var path = this.getAttachmentPath();
-    if (!path) return;
+    var attachTo = this.getAttachmentPath();
+    if (!attachTo) return;
 
-    var uid = path.scope.generateUidIdentifier("ref");
+    // don't bother hoisting to the same function as this will cause multiple branches to be evaluated more than once leading to a bad optimisation
+    if (attachTo.getFunctionParent() === this.path.getFunctionParent()) return;
 
-    path.insertBefore([
+    var uid = attachTo.scope.generateUidIdentifier("ref");
+
+    attachTo.insertBefore([
       t.variableDeclaration("var", [
         t.variableDeclarator(uid, this.path.node)
       ])
@@ -122,7 +125,7 @@ export default class PathHoister {
     if (parent.isJSXElement() && this.path.container === parent.node.children) {
       // turning the `span` in `<div><span /></div>` to an expression so we need to wrap it with
       // an expression container
-      uid = t.jSXExpressionContainer(uid);
+      uid = t.JSXExpressionContainer(uid);
     }
 
     this.path.replaceWith(uid);

src/babel/traversal/path/lib/virtual-types.js

@@ -25,6 +25,22 @@ export var BindingIdentifier = {
   }
 };
 
+export var Statement = {
+  types: ["Statement"],
+  checkPath({ node, parent }) {
+    if (t.isStatement(node)) {
+      if (t.isVariableDeclaration(node)) {
+        if (t.isForXStatement(parent, { left: node })) return false;
+        if (t.isForStatement(parent, { init: node })) return false;
+      }
+
+      return true;
+    } else {
+      return false;
+    }
+  }
+};
+
 export var Expression = {
   types: ["Expression"],
   checkPath(path) {
@@ -61,3 +77,29 @@ export var Var = {
     return t.isVar(path.node);
   }
 };
+
+export var DirectiveLiteral = {
+  types: ["Literal"],
+  checkPath(path) {
+    return path.isLiteral() && path.parentPath.isExpressionStatement();
+  }
+};
+
+export var Directive = {
+  types: ["ExpressionStatement"],
+  checkPath(path) {
+    return path.get("expression").isLiteral();
+  }
+};
+
+export var User = {
+  checkPath(path) {
+    return path.node && !!path.node.loc;
+  }
+};
+
+export var Generated = {
+  checkPath(path) {
+    return !path.isUser();
+  }
+};

src/babel/traversal/path/modification.js

@@ -3,7 +3,7 @@ import NodePath from "./index";
 import * as t from "../../types";
 
 /**
- * Description
+ * Insert the provided nodes before the current one.
  */
 
 export function insertBefore(nodes) {
@@ -75,7 +75,8 @@ export function _maybePopFromStatements(nodes) {
 }
 
 /**
- * Description
+ * Insert the provided nodes after the current one. When inserting nodes after an
+ * expression, ensure that the completion record is correct by pushing the current node.
  */
 
 export function insertAfter(nodes) {
@@ -108,7 +109,7 @@ export function insertAfter(nodes) {
 }
 
 /**
- * Description
+ * Update all sibling node paths after `fromIndex` by `incrementBy`.
  */
 
 export function updateSiblingKeys(fromIndex, incrementBy) {
@@ -121,10 +122,6 @@ export function updateSiblingKeys(fromIndex, incrementBy) {
   }
 }
 
-/**
- * Description
- */
-
 /**
  * Description
  */
@@ -200,7 +197,8 @@ export function pushContainer(listKey, nodes) {
 }
 
 /**
- * Description
+ * Hoist the current node to the highest scope possible and return a UID
+ * referencing it.
  */
 
 export function hoist(scope = this.scope) {

src/babel/traversal/path/removal.js

@@ -11,7 +11,8 @@ export function remove() {
 }
 
 /**
- * Description
+ * Dangerously remove the current node. This may sometimes result in a tainted
+ * invalid AST so use with caution.
  */
 
 export function dangerouslyRemove() {

src/babel/traversal/path/replacement.js

@@ -32,7 +32,11 @@ var hoistVariablesVisitor = {
 };
 
 /**
- * Description
+ * Replace a node with an array of multiple. This method performs the following steps:
+ *
+ *  - Inherit the comments of first provided node with that of the current node.
+ *  - Insert the provided nodes after the current node.
+ *  - Remove the current node.
  */
 
 export function replaceWithMultiple(nodes: Array<Object>) {
@@ -46,7 +50,11 @@ export function replaceWithMultiple(nodes: Array<Object>) {
 }
 
 /**
- * Description
+ * Parse a string as an expression and replace the current node with the result.
+ *
+ * NOTE: This is typically not a good idea to use. Building source strings when
+ * transforming ASTs is an antipattern and SHOULD NOT be encouraged. Even if it's
+ * easier to use, your transforms will be extremely brittle.
  */
 
 export function replaceWithSourceString(replacement) {
@@ -70,7 +78,7 @@ export function replaceWithSourceString(replacement) {
 }
 
 /**
- * Description
+ * Replace the current node with another.
  */
 
 export function replaceWith(replacement, whateverAllowed) {
@@ -92,14 +100,14 @@ export function replaceWith(replacement, whateverAllowed) {
     return;
   }
 
+  if (this.isProgram() && !t.isProgram(replacement)) {
+    throw new Error("You can only replace a Program root node with another Program node");
+  }
+
   // normalise inserting an entire AST
   if (t.isProgram(replacement) && !this.isProgram()) {
     replacement = replacement.body;
     whateverAllowed = true;
-  } else {
-    if (this.isProgram()) {
-      throw new Error("You can only replace a Program root node with another Program node");
-    }
   }
 
   if (Array.isArray(replacement)) {
@@ -112,6 +120,13 @@ export function replaceWith(replacement, whateverAllowed) {
 
   if (typeof replacement === "string") {
     if (whateverAllowed) {
+      this.hub.file.log.deprecate("Returning a string from a visitor method will be removed in the future. String " +
+                                  "building is NOT a substitute for AST generation. String building leads to " +
+                                  "terrible performance due to the additional parsing overhead and will lead to " +
+                                  "extremely brittle transformers. For those extreme cases where you're dealing " +
+                                  "with strings from a foreign source you may continue to use " +
+                                  "`path.replaceWithSourceString(code)`. Please don't abuse this. Bad plugins " +
+                                  "hurt the ecosystem.");
       return this.replaceWithSourceString(replacement);
     } else {
       throw new Error("Don't use `path.replaceWith()` with a string, use `path.replaceWithSourceString()`");
@@ -140,7 +155,9 @@ export function replaceWith(replacement, whateverAllowed) {
 }
 
 /**
- * Description
+ * This method takes an array of statements nodes and then explodes it
+ * into expressions. This method retains completion records which is
+ * extremely important to retain original semantics.
  */
 
 export function replaceExpressionWithStatements(nodes: Array) {

src/babel/traversal/scope/index.js

@@ -146,7 +146,7 @@ export default class Scope {
     }
 
     var cached = path.getData("scope");
-    if (cached && cached.parent === parent) {
+    if (cached && cached.parent === parent && cached.block === path.node) {
       return cached;
     } else {
       path.setData("scope", this);
@@ -491,32 +491,32 @@ export default class Scope {
     }
 
     var parent = this.getProgramParent();
-    var ids = path.getBindingIdentifiers();
+    var ids = path.getBindingIdentifiers(true);
 
     for (var name in ids) {
-      var id = ids[name];
+      for (var id of (ids[name]: Array)) {
+        var local = this.getOwnBinding(name);
+        if (local) {
+          // don't ever let a type alias shadow a local binding
+          if (kind === "type") continue;
 
-      var local = this.getOwnBinding(name);
-      if (local) {
-        // don't ever let a type alias shadow a local binding
-        if (kind === "type") continue;
+          // same identifier so continue safely as we're likely trying to register it
+          // multiple times
+          if (local.identifier === id) continue;
 
-        // same identifier so continue safely as we're likely trying to register it
-        // multiple times
-        if (local.identifier === id) continue;
+          this.checkBlockScopedCollisions(local, kind, name, id);
+        }
 
-        this.checkBlockScopedCollisions(local, kind, name, id);
+        parent.references[name] = true;
+
+        this.bindings[name] = new Binding({
+          identifier: id,
+          existing:   local,
+          scope:      this,
+          path:       path,
+          kind:       kind
+        });
       }
-
-      parent.references[name] = true;
-
-      this.bindings[name] = new Binding({
-        identifier: id,
-        existing:   local,
-        scope:      this,
-        path:       path,
-        kind:       kind
-      });
     }
   }
 

src/babel/traversal/visitors.js

@@ -126,6 +126,8 @@ export function merge(visitors) {
   var rootVisitor = {};
 
   for (var visitor of (visitors: Array)) {
+    explode(visitor);
+
     for (var type in visitor) {
       var nodeVisitor = rootVisitor[type] = rootVisitor[type] || {};
       mergePair(nodeVisitor, visitor[type]);

src/babel/types/alias-keys.json

@@ -71,6 +71,7 @@
   "MetaProperty":              ["Expression"],
   "NewExpression":             ["Expression"],
   "ObjectExpression":          ["Expression"],
+  "ParenthesizedExpression":   ["Expression"],
   "SequenceExpression":        ["Expression"],
   "TaggedTemplateExpression":  ["Expression"],
   "ThisExpression":            ["Expression"],

src/babel/types/converters.js

@@ -261,18 +261,22 @@ export function toBlock(node: Object, parent: Object): Object {
  */
 
 export function valueToNode(value: any): Object {
+  // undefined
   if (value === undefined) {
     return t.identifier("undefined");
   }
 
+  // null, booleans, strings, numbers, regexs
   if (value === true || value === false || value === null || isString(value) || isNumber(value) || isRegExp(value)) {
     return t.literal(value);
   }
 
+  // array
   if (Array.isArray(value)) {
     return t.arrayExpression(value.map(t.valueToNode));
   }
 
+  // object
   if (isPlainObject(value)) {
     var props = [];
     for (var key in value) {

src/babel/types/flow.js

@@ -112,5 +112,9 @@ export function createTypeAnnotationBasedOnTypeof(type) {
     return t.genericTypeAnnotation(t.identifier("Function"));
   } else if (type === "object") {
     return t.genericTypeAnnotation(t.identifier("Object"));
+  } else if (type === "symbol") {
+    return t.genericTypeAnnotation(t.identifier("Symbol"));
+  } else {
+    throw new Error("Invalid typeof value");
   }
 }

src/babel/types/index.js

@@ -108,7 +108,7 @@ each(t.VISITOR_KEYS, function (keys, type) {
 });
 
 each(t.BUILDER_KEYS, function (keys, type) {
-  t[type[0].toLowerCase() + type.slice(1)] = function () {
+  var builder = function () {
     var node = {};
     node.start = null;
     node.type = type;
@@ -123,6 +123,9 @@ each(t.BUILDER_KEYS, function (keys, type) {
 
     return node;
   };
+
+  t[type] = builder;
+  t[type[0].toLowerCase() + type.slice(1)] = builder;
 });
 
 /*

src/babel/types/retrievers.js

@@ -5,7 +5,7 @@ import * as t from "./index";
  * Return a list of binding identifiers associated with the input `node`.
  */
 
-export function getBindingIdentifiers(node: Object): Object {
+export function getBindingIdentifiers(node: Object, duplicates?): Object {
   var search = [].concat(node);
   var ids    = object();
 
@@ -16,7 +16,12 @@ export function getBindingIdentifiers(node: Object): Object {
     var key = t.getBindingIdentifiers.keys[id.type];
 
     if (t.isIdentifier(id)) {
-      ids[id.name] = id;
+      if (duplicates) {
+        var _ids = ids[id.name] = ids[id.name] || [];
+        _ids.push(id);
+      } else {
+        ids[id.name] = id;
+      }
     } else if (t.isExportDeclaration(id)) {
       if (t.isDeclaration(node.declaration)) {
         search.push(node.declaration);

src/babel/types/validators.js

@@ -23,7 +23,7 @@ export function isReferenced(node: Object, parent: Object): boolean {
   switch (parent.type) {
     // yes: PARENT[NODE]
     // yes: NODE.child
-    // no: parent.CHILD
+    // no: parent.NODE
     case "MemberExpression":
     case "JSXMemberExpression":
       if (parent.property === node && parent.computed) {
@@ -73,21 +73,17 @@ export function isReferenced(node: Object, parent: Object): boolean {
         return parent.local === node;
       }
 
-    // no: import NODE from "foo";
-    case "ImportDefaultSpecifier":
-      return false;
-
-    // no: import * as NODE from "foo";
-    case "ImportNamespaceSpecifier":
-      return false;
-
     // no: <div NODE="foo" />
     case "JSXAttribute":
       return parent.name !== node;
 
+    // no: import NODE from "foo";
+    // no: import * as NODE from "foo";
     // no: import { NODE as foo } from "foo";
     // no: import { foo as NODE } from "foo";
     // no: import NODE from "bar";
+    case "ImportDefaultSpecifier":
+    case "ImportNamespaceSpecifier":
     case "ImportSpecifier":
       return false;
 
@@ -112,12 +108,16 @@ export function isReferenced(node: Object, parent: Object): boolean {
     case "RestElement":
       return false;
 
-    // no: [NODE = foo] = [];
-    // yes: [foo = NODE] = [];
+    // yes: left = NODE;
+    // no: NODE = right;
     case "AssignmentExpression":
-    case "AssignmentPattern":
       return parent.right === node;
 
+    // no: [NODE = foo] = [];
+    // no: [foo = NODE] = [];
+    case "AssignmentPattern":
+      return false;
+
     // no: [NODE] = [];
     // no: ({ NODE }) = [];
     case "ObjectPattern":
@@ -195,7 +195,7 @@ export function isImmutable(node: Object): boolean {
 
   if (t.isLiteral(node)) {
     if (node.regex) {
-      // regexes are mutable
+      // regexs are mutable
       return false;
     } else {
       // immutable!

src/babel/types/visitor-keys.json

@@ -46,6 +46,7 @@
   "Noop":                      [],
   "ObjectExpression":          ["properties"],
   "ObjectPattern":             ["properties", "typeAnnotation"],
+  "ParenthesizedExpression":   ["expression"],
   "Program":                   ["body"],
   "Property":                  ["key", "value", "decorators"],
   "RestElement":               ["argument", "typeAnnotation"],

src/babel/util.js

@@ -18,6 +18,7 @@ import has from "lodash/object/has";
 import fs from "fs";
 import * as t from "./types";
 import slash from "slash";
+import pathExists from "path-exists";
 
 export { inherits, inspect } from "util";
 
@@ -55,7 +56,7 @@ export function resolveRelative(loc: string) {
   }
 }
 
-export function list(val: string): Array<string> {
+export function list(val: string): Array {
   if (!val) {
     return [];
   } else if (Array.isArray(val)) {
@@ -113,18 +114,26 @@ export function shouldIgnore(filename, ignore, only) {
 
   if (only) {
     for (let pattern of (only: Array)) {
-      if (pattern.test(filename)) return false;
+      if (_shouldIgnore(pattern, filename)) return false;
     }
     return true;
   } else if (ignore.length) {
     for (let pattern of (ignore: Array)) {
-      if (pattern.test(filename)) return true;
+      if (_shouldIgnore(pattern, filename)) return true;
     }
   }
 
   return false;
 }
 
+function _shouldIgnore(pattern, filename) {
+  if (typeof pattern === "function") {
+    return pattern(filename);
+  } else {
+    return pattern.test(filename);
+  }
+}
+
 var templateVisitor = {
   noScope: true,
 
@@ -182,7 +191,7 @@ function loadTemplates() {
   var templates = {};
 
   var templatesLoc = path.join(__dirname, "transformation/templates");
-  if (!fs.existsSync(templatesLoc)) {
+  if (!pathExists.sync(templatesLoc)) {
     throw new ReferenceError(messages.get("missingTemplatesDirectory"));
   }
 

test/acorn/tests-babel.js

@@ -3374,6 +3374,49 @@ test("class Foo { bar(a,) { } }", {
   features: { "es7.trailingFunctionCommas": true }
 });
 
+test("(x, y, ) => 1;", {
+  start: 0,
+  body: [{
+    start: 0,
+    expression: {
+      start: 0,
+      id: null,
+      generator: false,
+      expression: true,
+      params: [
+        {
+          start: 1,
+          name: "x",
+          type: "Identifier",
+          end: 2
+        },
+        {
+          start: 4,
+          name: "y",
+          type: "Identifier",
+          end: 5
+        }
+      ],
+      body: {
+        start: 12,
+        value: 1,
+        raw: "1",
+        type: "Literal",
+        end: 13
+      },
+      type: "ArrowFunctionExpression",
+      end: 13
+    },
+    type: "ExpressionStatement",
+    end: 14
+  }],
+  type: "Program",
+  end: 14
+}, {
+  ecmaVersion: 7,
+  features: { "es7.trailingFunctionCommas": true }
+});
+
 testFail("log(,);", "Unexpected token (1:4)", {
   ecmaVersion: 7,
   features: { "es7.trailingFunctionCommas": true }
@@ -3383,3 +3426,8 @@ testFail("function log(,) { }", "Unexpected token (1:13)", {
   ecmaVersion: 7,
   features: { "es7.trailingFunctionCommas": true }
 });
+
+testFail("('foo',)", "Unexpected token (1:7)", {
+  ecmaVersion: 7,
+  features: { "es7.trailingFunctionCommas": true }
+});

test/acorn/tests-flow.js

@@ -9965,6 +9965,95 @@ var fbTestFixture = {
         end: { line: 1, column: 49 }
       }
     },
+    'declare class IViewFactory { didAnimate(view:Object, prop:string) :void; }': {
+      start: 0,
+      id: {
+        start: 14,
+        name: "IViewFactory",
+        type: "Identifier",
+        end: 26
+      },
+      typeParameters: null,
+      extends: [],
+      body: {
+        start: 27,
+        callProperties: [],
+        properties: [
+          {
+            start: 29,
+            value: {
+              start: 29,
+              params: [
+                {
+                  start: 40,
+                  name: {
+                    start: 40,
+                    name: "view",
+                    type: "Identifier",
+                    end: 44
+                  },
+                  optional: false,
+                  typeAnnotation: {
+                    start: 45,
+                    typeParameters: null,
+                    id: {
+                      start: 45,
+                      name: "Object",
+                      type: "Identifier",
+                      end: 51
+                    },
+                    type: "GenericTypeAnnotation",
+                    end: 51
+                  },
+                  type: "FunctionTypeParam",
+                  end: 51
+                },
+                {
+                  start: 53,
+                  name: {
+                    start: 53,
+                    name: "prop",
+                    type: "Identifier",
+                    end: 57
+                  },
+                  optional: false,
+                  typeAnnotation: {
+                    start: 58,
+                    type: "StringTypeAnnotation",
+                    end: 64
+                  },
+                  type: "FunctionTypeParam",
+                  end: 64
+                }
+              ],
+              rest: null,
+              typeParameters: null,
+              returnType: {
+                start: 67,
+                type: "VoidTypeAnnotation",
+                end: 71
+              },
+              type: "FunctionTypeAnnotation",
+              end: 71
+            },
+            key: {
+              start: 29,
+              name: "didAnimate",
+              type: "Identifier",
+              end: 39
+            },
+            optional: false,
+            type: "ObjectTypeProperty",
+            end: 72
+          }
+        ],
+        indexers: [],
+        type: "ObjectTypeAnnotation",
+        end: 74
+      },
+      type: "DeclareClass",
+      end: 74
+    },
     'declare class A {}': {
       type: 'DeclareClass',
       id: {
@@ -11148,3 +11237,9 @@ for (var ns in fbTestFixture) {
     });
   }
 }
+
+test("<Foo foo={function (): void {}} />", {}, {
+  ecmaVersion: 6,
+  sourceType: "module",
+  plugins: { jsx: true, flow: true },
+});

test/acorn/tests-harmony.js

@@ -15328,3 +15328,5 @@ test("({ ['__proto__']: 1, __proto__: 2 })", {}, {ecmaVersion: 6});
 test("({ __proto__() { return 1 }, __proto__: 2 })", {}, {ecmaVersion: 6});
 test("({ get __proto__() { return 1 }, __proto__: 2 })", {}, {ecmaVersion: 6});
 test("({ __proto__, __proto__: 2 })", {}, {ecmaVersion: 6});
+
+test("export default /foo/", {}, {ecmaVersion: 6, sourceType: "module"});

test/core/_helper.js

@@ -1,8 +1,9 @@
-var esvalid = require("esvalid");
-var util    = require("../../lib/babel/util");
-var path    = require("path");
-var fs      = require("fs");
-var _       = require("lodash");
+var pathExists = require("path-exists");
+var esvalid    = require("esvalid");
+var util       = require("../../lib/babel/util");
+var path       = require("path");
+var fs         = require("fs");
+var _          = require("lodash");
 
 var humanize = function (val, noext) {
   if (noext) val = path.basename(val, path.extname(val));
@@ -10,7 +11,7 @@ var humanize = function (val, noext) {
 };
 
 var readFile = exports.readFile = function (filename) {
-  if (fs.existsSync(filename)) {
+  if (pathExists.sync(filename)) {
     var file = fs.readFileSync(filename, "utf8").trim();
     file = file.replace(/\r\n/g, "\n");
     return file;
@@ -31,7 +32,7 @@ exports.esvalid = function (ast, code, loc) {
 };
 
 exports.assertVendor = function (name) {
-  if (!fs.existsSync(__dirname + "/../../vendor/" + name)) {
+  if (!pathExists.sync(__dirname + "/../../vendor/" + name)) {
     console.error("No vendor/" + name + " - run `make bootstrap`");
     process.exit(1);
   }
@@ -130,13 +131,13 @@ exports.get = function (entryName, entryLoc) {
       suite.tests.push(test);
 
       var sourceMappingsLoc = taskDir + "/source-mappings.json";
-      if (fs.existsSync(sourceMappingsLoc)) {
+      if (pathExists.sync(sourceMappingsLoc)) {
         test.options.sourceMap = true;
         test.sourceMappings = require(sourceMappingsLoc);
       }
 
       var sourceMap = taskDir + "/source-map.json";
-      if (fs.existsSync(sourceMap)) {
+      if (pathExists.sync(sourceMap)) {
         test.options.sourceMap = true;
         test.sourceMap = require(sourceMap);
       }

test/core/api.js

@@ -70,7 +70,7 @@ suite("api", function () {
 
     assert.deepEqual(transform('import localName from "./array";', {
       resolveModuleSource: function() {
-        return 'override-source';
+        return "override-source";
       }
     }).metadata.modules.imports, [
       {
@@ -219,7 +219,7 @@ suite("api", function () {
 
     function getModuleNameTest(moduleFormat, expected) {
       var result = transform("foo('bar');", {
-        filename: "foo/bar/index",
+        filename: "/foo/bar/index",
         modules: moduleFormat,
         moduleIds: true,
         getModuleId: function (name) {
@@ -232,7 +232,7 @@ suite("api", function () {
 
     test("amd", function () {
       var expected = [
-        "define('foo/bar', ['exports'], function (exports) {",
+        "define('/foo/bar', ['exports'], function (exports) {",
         "  'use strict';",
         "",
         "  foo('bar');",
@@ -246,7 +246,7 @@ suite("api", function () {
       var expected = [
         "(function (global, factory) {",
         "  if (typeof define === 'function' && define.amd) {",
-        "    define('foo/bar', ['exports'], factory);",
+        "    define('/foo/bar', ['exports'], factory);",
         "  } else if (typeof exports !== 'undefined') {",
         "    factory(exports);",
         "  } else {",
@@ -268,7 +268,7 @@ suite("api", function () {
 
     test("system", function () {
       var expected = [
-        "System.register('foo/bar', [], function (_export) {",
+        "System.register('/foo/bar', [], function (_export) {",
         "  'use strict';",
         "",
         "  return {",

test/core/bin.js

@@ -9,6 +9,7 @@ var child          = require("child_process");
 var path           = require("path");
 var chai           = require("chai");
 var fs             = require("fs");
+var pathExists     = require("path-exists");
 var _              = require("lodash");
 
 var fixtureLoc = __dirname + "/fixtures/bin";
@@ -16,7 +17,7 @@ var tmpLoc = __dirname + "/tmp";
 
 var readDir = function (loc) {
   var files = {};
-  if (fs.existsSync(loc)) {
+  if (pathExists.sync(loc)) {
     _.each(readdir(loc), function (filename) {
       var contents = helper.readFile(loc + "/" + filename);
       files[filename] = contents;
@@ -112,7 +113,7 @@ var buildTest = function (binName, testName, opts) {
 
 var clear = function () {
   process.chdir(__dirname);
-  if (fs.existsSync(tmpLoc)) rimraf.sync(tmpLoc);
+  if (pathExists.sync(tmpLoc)) rimraf.sync(tmpLoc);
   fs.mkdirSync(tmpLoc);
   process.chdir(tmpLoc);
 };
@@ -132,11 +133,11 @@ _.each(fs.readdirSync(fixtureLoc), function (binName) {
       };
 
       var optionsLoc = testLoc + "/options.json"
-      if (fs.existsSync(optionsLoc)) _.merge(opts, require(optionsLoc));
+      if (pathExists.sync(optionsLoc)) _.merge(opts, require(optionsLoc));
 
       _.each(["stdout", "stdin", "stderr"], function (key) {
         var loc = testLoc + "/" + key + ".txt";
-        if (fs.existsSync(loc)) {
+        if (pathExists.sync(loc)) {
           opts[key] = helper.readFile(loc);
         } else {
           opts[key] = opts[key] || "";

test/core/fixtures/generation/types/Decorator/actual.js

@@ -0,0 +1,31 @@
+var obj = {
+  @foo
+  @bar
+  foo: "bar",
+
+  @foo
+  @bar
+  foo() {},
+
+  @foo
+  get foo() {},
+
+  @bar
+  set bar(foo) {}
+};
+
+class Foo {
+  @foo
+  @bar
+  foo() {}
+
+  @foo
+  @bar
+  foo() {}
+
+  @foo
+  get foo() {}
+
+  @bar
+  set bar(foo) {}
+}

test/core/fixtures/generation/types/Decorator/expected.js

@@ -0,0 +1,31 @@
+var obj = {
+  @foo
+  @bar
+  foo: "bar",
+
+  @foo
+  @bar
+  foo() {},
+
+  @foo
+  get foo() {},
+
+  @bar
+  set bar(foo) {}
+};
+
+class Foo {
+  @foo
+  @bar
+  foo() {}
+
+  @foo
+  @bar
+  foo() {}
+
+  @foo
+  get foo() {}
+
+  @bar
+  set bar(foo) {}
+}

test/core/fixtures/transformation/.es7.do-expressions/do-while.js

@@ -1 +0,0 @@
-assert.ok(false);

test/core/fixtures/transformation/.es7.do-expressions/nested-dos.js

@@ -1,3 +0,0 @@
-assert.equal(do {
-  do { "foo" };
-}, "foo");

test/core/fixtures/transformation/.es7.do-expressions/while.js

@@ -1 +0,0 @@
-assert.ok(false);

test/core/fixtures/transformation/es6.arrow-functions/default-parameters/expected.js

@@ -1,9 +1,9 @@
 "use strict";
 
 var some = function some() {
-  var count = arguments[0] === undefined ? "30" : arguments[0];
+  var count = arguments.length <= 0 || arguments[0] === undefined ? "30" : arguments[0];
 
   console.log("count", count);
 };
 
-some();
+some();

test/core/fixtures/transformation/es6.classes-loose/constructor-order/actual.js

@@ -0,0 +1,13 @@
+class x {
+  f() {
+    1
+    2
+    3
+  }
+
+  constructor() {
+    4
+    5
+    6
+  }
+}

test/core/fixtures/transformation/es6.classes-loose/constructor-order/expected.js

@@ -0,0 +1,18 @@
+"use strict";
+
+var x = (function () {
+  x.prototype.f = function f() {
+    1;
+    2;
+    3;
+  };
+
+  function x() {
+    4;
+    5;
+    6;
+    babelHelpers.classCallCheck(this, x);
+  }
+
+  return x;
+})();

test/core/fixtures/transformation/es6.classes/constructor/actual.js

@@ -10,3 +10,12 @@ class Foo extends Bar {
     this.state = "test";
   }
 }
+
+class ConstructorScoping {
+  constructor(){
+    let bar;
+    {
+      let bar;
+    }
+  }
+}