v5.5.3

This reverts commit f3acedbf08.

.eslintrc

@@ -3,18 +3,21 @@
   "rules": {
     "strict": 0,
     "no-underscore-dangle": 0,
-    "no-unused-vars": 0,
     "curly": 0,
     "no-multi-spaces": 0,
     "key-spacing": 0,
     "no-return-assign": 0,
     "consistent-return": 0,
     "no-shadow": 0,
-    "no-comma-dangle": 0,
+    "comma-dangle": 0,
     "no-use-before-define": 0,
     "no-empty": 0,
     "new-parens": 0,
-    "no-cond-assign": 0
+    "no-cond-assign": 0,
+    "no-fallthrough": 0,
+    "new-cap": 0,
+    "no-loop-func": 0,
+    "no-unreachable": 0
   },
   "env": {
     "node": true

.gitignore

@@ -8,10 +8,10 @@ test/core/tmp
 /browser.js
 /browser-polyfill.js
 /runtime.js
-coverage
-dist
-.package.json
-packages/babel-runtime/core-js
-packages/babel-runtime/helpers/*.js
-packages/babel-runtime/regenerator/*.js
-lib
+/coverage
+/dist
+/.package.json
+/packages/babel-runtime/core-js
+/packages/babel-runtime/helpers/*.js
+/packages/babel-runtime/regenerator/*.js
+/lib

CHANGELOG.md

@@ -13,6 +13,68 @@ _Note: Gaps between patch versions are faulty/broken releases._
 
 See [CHANGELOG - 6to5](CHANGELOG-6to5.md) for the pre-4.0.0 version changelog.
 
+## 5.5.3
+
+ * **Bug Fix**
+  * Fix weird state bug when traversing overa  `node` `ClassProperty` instead of `path` in the `es6.classes` transformer.
+
+## 5.5.2
+
+ * **Bug Fix**
+  * Fix `NodePath#isPure` on `Property` nodes.
+  * Use cwd instead of entry file directory when working out relative directory for `babel/register`.
+ * **Internal**
+  * Add scary warning for those few who choose to use the WIP experimental transformers.
+
+## 5.5.1
+
+ * **Bug Fix**
+  * Remove `ClassProperty` nodes always in the `Flow` transformer. This is fine now since class properties aren't supported in any engine that supports classes but the `es7.classProperties` transformer will need to be updated in the future to desugar to ES6 classes instead of relying on the `es6.classes` transformer from being ran.
+
+## 5.5.0
+
+ * **Bug Fix**
+  * Allow pushing declarations to `SwitchStatement`s.
+  * Fix `minification.removeDebugger` to remove `DebuggerStatement`s rather than `ExpressionStatement`s with an identifier of `debugger`.
+  * Check LHS in `ForInStatement` and `ForOfStatement` for constant violations.
+  * Register function `id` as a reference when naming methods to avoid collisions.
+  * Support key literals when checking for the existence of `displayName` property when attempting to add it for `React.createClass`.
+  * Remove `ExportDefaultSpecifier` check from `t.isDefaultSpecifier`.
+  * Don't consider `JSXIdentifier` HTML tag identifiers to be references.
+ * **Polish**
+  * Update `minification.deadCodeElimination` transformer to remove all statements after completion statements.
+  * Update `minification.deadCodeElimination` transformer to not inline single used bindings that exist in different scopes.
+  * When performing Istanbul interop in `babel/register`, add the auxiliary comment `"istanbul ignore text"` to get more accurate coverage.
+  * Add `--nolazy` argument to `babel-node`.
+  * Add support for `cluster` forking.
+  * Perform scope tracking in a single pass instead of multiple.
+  * Smarten up type inferrence and resolution to support the whole array of language constructs.
+  * Optimise module metadata retrieval into a single pass.
+  * Ignore trailing commas when inferring newlines.
+  * Rename `minification.inlineExpressions` transformer to `minification.constantFolding`.
+  * Check path relative to entry file when checking to see if we're inside `node_modules` when using `babel/register`.
+  * Upgrade `regenerator`.
+
+## 5.4.7
+
+ * **Bug Fix**
+  * Don't consider `JSXAttribute` `names` to be valid `ReferencedIdentifier`s.
+
+## 5.4.6
+
+ * **Bug Fix**
+  * Fix `spec.functionName` transformer incorrectly attempting to rename a binding that doesn't exist as it's a global.
+ * **Internal**
+  * Deprecate custom module formatters.
+
+## 5.4.5
+
+ * **Bug Fix**
+  * Add `JSXIdentifier` as a valid `ReferencedIdentifier` visitor virtual type.
+  * Ignore `CallExpression` `_prettyCall` when the `retainLines` option is enabled.
+  * Inherit comments to new declaration node when exploding module declarations.
+  * Fix `es6.tailCall` transformer failing on calls that exceed the max parameters of the function.
+
 ## 5.4.4
 
  * **Bug Fix**

CONTRIBUTING.md

@@ -1,3 +1,7 @@
+# NOTE: BEFORE OPENING AN ISSUE PLEASE SEE THE [README](https://github.com/babel/babel#readme).
+
+----
+
 <p align="center">
    <strong><a href="#setup">Setup</a></strong>
    |
@@ -21,6 +25,9 @@ contributing, please read the
 
 ## Developing
 
+>Note: Babel moves fast. Only the latest release is guaranteed to build correctly.
+>Older releases are not officially supported. If you attempt to build them, do that at your own risk.
+
 #### Setup
 
 ```sh
@@ -79,7 +86,6 @@ your [`$PATH`](http://unix.stackexchange.com/questions/26047/how-to-correctly-ad
 * Ensure the test are passing (`make test`)
 * Create new pull request explaining your proposed change or reference an issue in your commit message
 
-
 #### Dependencies
 
 + [ast-types](http://ghub.io/ast-types) This is required to monkeypatch regenerators AST definitions. Could be improved in the future.

Makefile

@@ -22,6 +22,9 @@ watch-core: clean-core
 clean-core:
 	rm -rf lib
 
+lint:
+	eslint src/babel
+
 build:
 	mkdir -p dist
 	make build-core
@@ -61,7 +64,7 @@ test-cov:
 test-parser:
 	node test/acorn/run.js
 
-test-travis: bootstrap build test
+test-travis: bootstrap lint build test
 
 test-browser:
 	mkdir -p dist
@@ -73,7 +76,7 @@ test-browser:
 
 	test -n "`which open`" && open test/browser.html
 
-publish:
+publish: lint
 	git pull --rebase
 
 	make test

README.md

@@ -12,6 +12,10 @@
   For questions and support please visit the <a href="https://gitter.im/babel/babel">gitter room</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">
+  Issues without instructions to reproduce <strong>will be immediately closed<strong>.
+</p>
+
 <p align="center">
   For documentation and website issues please visit the <a href="https://github.com/babel/babel.github.io">babel.github.io</a> repo.
 </p>

package.json

@@ -1,7 +1,7 @@
 {
   "name": "babel-core",
   "description": "A compiler for writing next generation JavaScript",
-  "version": "5.4.4",
+  "version": "5.5.3",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://babeljs.io/",
   "license": "MIT",
@@ -51,7 +51,7 @@
     "output-file-sync": "^1.1.0",
     "path-is-absolute": "^1.0.0",
     "private": "^0.1.6",
-    "regenerator": "^0.8.20",
+    "regenerator": "^0.8.28",
     "regexpu": "^1.1.2",
     "repeating": "^1.1.2",
     "resolve": "^1.1.6",
@@ -67,8 +67,8 @@
     "babel": "5.3.1",
     "browserify": "^9.0.8",
     "chai": "^2.2.0",
-    "eslint": "^0.18.0",
-    "babel-eslint": "^2.0.0",
+    "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

@@ -107,6 +107,7 @@ if (program.eval || program.print) {
 
     // add back on node and concat the sliced args
     process.argv = ["node"].concat(args);
+    process.execArgv.unshift(__filename);
 
     Module.runMain();
   } else {

packages/babel-cli/bin/babel-node

@@ -412,6 +412,7 @@ babelArgs.forEach(function(arg){
     case "--prof_auto":
     case "--prof_lazy":
     case "--sliding_state_window":
+    case "--nolazy":
       args.unshift(arg);
       break;
 

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

@@ -79,7 +79,9 @@ if (commander.extensions) {
 var errors = [];
 
 var filenames = commander.args.reduce(function (globbed, input) {
-  return globbed.concat(glob.sync(input));
+  var files = glob.sync(input);
+  if (!files.length) files = [input];
+  return globbed.concat(files);
 }, []);
 
 each(filenames, function (filename) {

packages/babel-cli/package.json

@@ -1,14 +1,14 @@
 {
   "name": "babel",
   "description": "Turn ES6 code into readable vanilla ES5 with source maps",
-  "version": "5.4.3",
+  "version": "5.5.2",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://babeljs.io/",
   "license": "MIT",
   "repository": "babel/babel",
   "preferGlobal": true,
   "dependencies": {
-    "babel-core": "^5.4.3",
+    "babel-core": "^5.5.2",
     "chokidar": "^1.0.0",
     "commander": "^2.6.0",
     "convert-source-map": "^1.1.0",

packages/babel-runtime/package.json

@@ -1,7 +1,7 @@
 {
   "name": "babel-runtime",
   "description": "babel selfContained runtime",
-  "version": "5.4.3",
+  "version": "5.5.2",
   "license": "MIT",
   "repository": "babel/babel",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",

src/acorn/plugins/flow.js

@@ -415,6 +415,9 @@ pp.flow_identToTypeAnnotation = function (start, node, id) {
     case "boolean":
       return this.finishNode(node, "BooleanTypeAnnotation")
 
+    case "mixed":
+      return this.finishNode(node, "MixedTypeAnnotation")
+
     case "number":
       return this.finishNode(node, "NumberTypeAnnotation")
 

src/acorn/src/expression.js

@@ -274,7 +274,13 @@ pp.parseExprAtom = function(refShorthandDefaultPos) {
     if (this.options.features["es7.doExpressions"]) {
       let node = this.startNode()
       this.next()
+      var oldInFunction = this.inFunction
+      var oldLabels = this.labels
+      this.labels = []
+      this.inFunction = false
       node.body = this.parseBlock()
+      this.inFunction = oldInFunction
+      this.labels = oldLabels
       return this.finishNode(node, "DoExpression")
     }
 
@@ -507,7 +513,7 @@ pp.parseNew = function() {
 pp.parseTemplateElement = function() {
   let elem = this.startNode()
   elem.value = {
-    raw: this.input.slice(this.start, this.end),
+    raw: this.input.slice(this.start, this.end).replace(/\r\n?/g, '\n'),
     cooked: this.value
   }
   this.next()

src/acorn/src/statement.js

@@ -168,12 +168,6 @@ pp.parseDoStatement = function(node) {
   this.labels.push(loopLabel)
   node.body = this.parseStatement(false)
   this.labels.pop()
-  if (this.options.features["es7.doExpressions"] && this.type !== tt._while) {
-    let container = this.startNodeAt(start)
-    container.expression = this.finishNode(node, "DoExpression")
-    this.semicolon()
-    return this.finishNode(container, "ExpressionStatement")
-  }
   this.expect(tt._while)
   node.test = this.parseParenExpression()
   if (this.options.ecmaVersion >= 6)
@@ -574,7 +568,7 @@ pp.parseExport = function(node) {
       this.parseExportFrom(node)
       return this.finishNode(node, "ExportAllDeclaration")
     }
-  } else if (this.isExportDefaultSpecifier()) {
+  } else if (this.options.features["es7.exportExtensions"] && this.isExportDefaultSpecifier()) {
     let specifier = this.startNode()
     specifier.exported = this.parseIdent(true)
     node.specifiers = [this.finishNode(specifier, "ExportDefaultSpecifier")]

src/acorn/src/tokenize.js

@@ -577,11 +577,15 @@ pp.readTmplToken = function() {
     } else if (isNewLine(ch)) {
       out += this.input.slice(chunkStart, this.pos)
       ++this.pos
-      if (ch === 13 && this.input.charCodeAt(this.pos) === 10) {
-        ++this.pos
-        out += "\n"
-      } else {
-        out += String.fromCharCode(ch)
+      switch (ch) {
+        case 13:
+          if (this.input.charCodeAt(this.pos) === 10) ++this.pos;
+        case 10:
+          out += "\n";
+          break;
+        default:
+          out += String.fromCharCode(ch);
+          break;
       }
       if (this.options.locations) {
         ++this.curLine

src/babel/api/browser.js

@@ -1,3 +1,5 @@
+/* eslint no-new-func: 0 */
+
 require("./node");
 var transform = module.exports = require("../transformation");
 

src/babel/api/register/browser.js

@@ -1,5 +1,5 @@
 // required to safely use babel/register within a browserify codebase
 
-export default function () {};
+export default function () {}
 
 import "../../polyfill";

src/babel/api/register/cache.js

@@ -1,5 +1,4 @@
 import path from "path";
-import os from "os";
 import fs from "fs";
 import homeOrTmp from "home-or-tmp";
 

src/babel/api/register/node.js

@@ -6,7 +6,7 @@ import * as babel from "../node";
 import each from "lodash/collection/each";
 import * as util from  "../../util";
 import fs from "fs";
-import slash from "slash";
+import path from "path";
 
 sourceMapSupport.install({
   handleUncaughtExceptions: false,
@@ -38,14 +38,20 @@ var only;
 var oldHandlers   = {};
 var maps          = {};
 
+var cwd = process.cwd();
+
+var getRelativePath = function (filename){
+  return path.relative(cwd, filename);
+};
+
 var mtime = function (filename) {
   return +fs.statSync(filename).mtime;
 };
 
-var compile = function (filename) {
+var compile = function (filename, opts = {}) {
   var result;
 
-  var opts = extend({}, transformOpts);
+  opts = extend(opts, transformOpts);
 
   // this will be done when the file is transformed anyway but we need all
   // the options so we can generate the cache key
@@ -82,7 +88,7 @@ var compile = function (filename) {
 
 var shouldIgnore = function (filename) {
   if (!ignore && !only) {
-    return /node_modules/.test(filename);
+    return getRelativePath(filename).split(path.sep).indexOf("node_modules") >= 0;
   } else {
     return util.shouldIgnore(filename, ignore || [], only || []);
   }
@@ -98,7 +104,9 @@ if (process.env.running_under_istanbul) {
   fs.readFileSync = function (filename) {
     if (istanbulMonkey[filename]) {
       delete istanbulMonkey[filename];
-      var code = compile(filename);
+      var code = compile(filename, {
+        attachAuxiliaryComment: "istanbul ignore next"
+      });
       istanbulMonkey[filename] = true;
       return code;
     } else {
@@ -164,4 +172,4 @@ export default function (opts = {}) {
   delete opts.only;
 
   extend(transformOpts, opts);
-};
+}

src/babel/generation/generators/base.js

@@ -1,5 +1,5 @@
 export function File(node, print) {
-  print(node.program);
+  print.plain(node.program);
 }
 
 export function Program(node, print) {

src/babel/generation/generators/classes.js

@@ -4,15 +4,15 @@ export function ClassDeclaration(node, print) {
 
   if (node.id) {
     this.push(" ");
-    print(node.id);
+    print.plain(node.id);
   }
 
-  print(node.typeParameters);
+  print.plain(node.typeParameters);
 
   if (node.superClass) {
     this.push(" extends ");
-    print(node.superClass);
-    print(node.superTypeParameters);
+    print.plain(node.superClass);
+    print.plain(node.superTypeParameters);
   }
 
   if (node.implements) {
@@ -21,7 +21,7 @@ export function ClassDeclaration(node, print) {
   }
 
   this.space();
-  print(node.body);
+  print.plain(node.body);
 }
 
 export { ClassDeclaration as ClassExpression };
@@ -46,13 +46,13 @@ export function ClassProperty(node, print) {
   print.list(node.decorators);
 
   if (node.static) this.push("static ");
-  print(node.key);
-  print(node.typeAnnotation);
+  print.plain(node.key);
+  print.plain(node.typeAnnotation);
   if (node.value) {
     this.space();
     this.push("=");
     this.space();
-    print(node.value);
+    print.plain(node.value);
   }
   this.semicolon();
 }

src/babel/generation/generators/comprehensions.js

@@ -1,9 +1,9 @@
 export function ComprehensionBlock(node, print) {
   this.keyword("for");
   this.push("(");
-  print(node.left);
+  print.plain(node.left);
   this.push(" of ");
-  print(node.right);
+  print.plain(node.right);
   this.push(")");
 }
 
@@ -16,12 +16,12 @@ export function ComprehensionExpression(node, print) {
   if (node.filter) {
     this.keyword("if");
     this.push("(");
-    print(node.filter);
+    print.plain(node.filter);
     this.push(")");
     this.space();
   }
 
-  print(node.body);
+  print.plain(node.body);
 
   this.push(node.generator ? ")" : "]");
 }

src/babel/generation/generators/expressions.js

@@ -16,40 +16,40 @@ export function UnaryExpression(node, print) {
 
   this.push(node.operator);
   if (hasSpace) this.push(" ");
-  print(node.argument);
+  print.plain(node.argument);
 }
 
 export function DoExpression(node, print) {
   this.push("do");
   this.space();
-  print(node.body);
+  print.plain(node.body);
 }
 
 export function UpdateExpression(node, print) {
   if (node.prefix) {
     this.push(node.operator);
-    print(node.argument);
+    print.plain(node.argument);
   } else {
-    print(node.argument);
+    print.plain(node.argument);
     this.push(node.operator);
   }
 }
 
 export function ConditionalExpression(node, print) {
-  print(node.test);
+  print.plain(node.test);
   this.space();
   this.push("?");
   this.space();
-  print(node.consequent);
+  print.plain(node.consequent);
   this.space();
   this.push(":");
   this.space();
-  print(node.alternate);
+  print.plain(node.alternate);
 }
 
 export function NewExpression(node, print) {
   this.push("new ");
-  print(node.callee);
+  print.plain(node.callee);
   this.push("(");
   print.list(node.arguments);
   this.push(")");
@@ -69,17 +69,19 @@ export function Super() {
 
 export function Decorator(node, print) {
   this.push("@");
-  print(node.expression);
+  print.plain(node.expression);
 }
 
 export function CallExpression(node, print) {
-  print(node.callee);
+  print.plain(node.callee);
 
   this.push("(");
 
   var separator = ",";
 
-  if (node._prettyCall) {
+  var isPrettyCall = node._prettyCall && !this.format.retainLines;
+
+  if (isPrettyCall) {
     separator += "\n";
     this.newline();
     this.indent();
@@ -89,7 +91,7 @@ export function CallExpression(node, print) {
 
   print.list(node.arguments, { separator: separator });
 
-  if (node._prettyCall) {
+  if (isPrettyCall) {
     this.newline();
     this.dedent();
   }
@@ -106,8 +108,8 @@ var buildYieldAwait = function (keyword) {
     }
 
     if (node.argument) {
-      this.space();
-      print(node.argument);
+      this.push(" ");
+      print.plain(node.argument);
     }
   };
 };
@@ -120,23 +122,23 @@ export function EmptyStatement() {
 }
 
 export function ExpressionStatement(node, print) {
-  print(node.expression);
+  print.plain(node.expression);
   this.semicolon();
 }
 
 export function AssignmentExpression(node, print) {
   // todo: add cases where the spaces can be dropped when in compact mode
-  print(node.left);
+  print.plain(node.left);
   this.push(" ");
   this.push(node.operator);
   this.push(" ");
-  print(node.right);
+  print.plain(node.right);
 }
 
 export function BindExpression(node, print) {
-  print(node.object);
+  print.plain(node.object);
   this.push("::");
-  print(node.callee);
+  print.plain(node.callee);
 }
 
 export {
@@ -149,7 +151,7 @@ var SCIENTIFIC_NOTATION = /e/i;
 
 export function MemberExpression(node, print) {
   var obj = node.object;
-  print(obj);
+  print.plain(obj);
 
   if (!node.computed && t.isMemberExpression(node.property)) {
     throw new TypeError("Got a MemberExpression for MemberExpression property");
@@ -162,7 +164,7 @@ export function MemberExpression(node, print) {
 
   if (computed) {
     this.push("[");
-    print(node.property);
+    print.plain(node.property);
     this.push("]");
   } else {
     // 5..toFixed(2);
@@ -171,12 +173,12 @@ export function MemberExpression(node, print) {
     }
 
     this.push(".");
-    print(node.property);
+    print.plain(node.property);
   }
 }
 
 export function MetaProperty(node, print) {
-  print(node.meta);
+  print.plain(node.meta);
   this.push(".");
-  print(node.property);
+  print.plain(node.property);
 }

src/babel/generation/generators/flow.js

@@ -5,7 +5,7 @@ export function AnyTypeAnnotation() {
 }
 
 export function ArrayTypeAnnotation(node, print) {
-  print(node.elementType);
+  print.plain(node.elementType);
   this.push("[");
   this.push("]");
 }
@@ -21,27 +21,27 @@ export function DeclareClass(node, print) {
 
 export function DeclareFunction(node, print) {
   this.push("declare function ");
-  print(node.id);
-  print(node.id.typeAnnotation.typeAnnotation);
+  print.plain(node.id);
+  print.plain(node.id.typeAnnotation.typeAnnotation);
   this.semicolon();
 }
 
 export function DeclareModule(node, print) {
   this.push("declare module ");
-  print(node.id);
+  print.plain(node.id);
   this.space();
-  print(node.body);
+  print.plain(node.body);
 }
 
 export function DeclareVariable(node, print) {
   this.push("declare var ");
-  print(node.id);
-  print(node.id.typeAnnotation);
+  print.plain(node.id);
+  print.plain(node.id.typeAnnotation);
   this.semicolon();
 }
 
 export function FunctionTypeAnnotation(node, print, parent) {
-  print(node.typeParameters);
+  print.plain(node.typeParameters);
   this.push("(");
   print.list(node.params);
 
@@ -51,7 +51,7 @@ export function FunctionTypeAnnotation(node, print, parent) {
       this.space();
     }
     this.push("...");
-    print(node.rest);
+    print.plain(node.rest);
   }
 
   this.push(")");
@@ -65,33 +65,33 @@ export function FunctionTypeAnnotation(node, print, parent) {
   }
 
   this.space();
-  print(node.returnType);
+  print.plain(node.returnType);
 }
 
 export function FunctionTypeParam(node, print) {
-  print(node.name);
+  print.plain(node.name);
   if (node.optional) this.push("?");
   this.push(":");
   this.space();
-  print(node.typeAnnotation);
+  print.plain(node.typeAnnotation);
 }
 
 export function InterfaceExtends(node, print) {
-  print(node.id);
-  print(node.typeParameters);
+  print.plain(node.id);
+  print.plain(node.typeParameters);
 }
 
 export { InterfaceExtends as ClassImplements, InterfaceExtends as GenericTypeAnnotation };
 
 export function _interfaceish(node, print) {
-  print(node.id);
-  print(node.typeParameters);
+  print.plain(node.id);
+  print.plain(node.typeParameters);
   if (node.extends.length) {
     this.push(" extends ");
     print.join(node.extends, { separator: ", " });
   }
   this.space();
-  print(node.body);
+  print.plain(node.body);
 }
 
 export function InterfaceDeclaration(node, print) {
@@ -103,9 +103,13 @@ export function IntersectionTypeAnnotation(node, print) {
   print.join(node.types, { separator: " & " });
 }
 
+export function MixedTypeAnnotation() {
+  this.push("mixed");
+}
+
 export function NullableTypeAnnotation(node, print) {
   this.push("?");
-  print(node.typeAnnotation);
+  print.plain(node.typeAnnotation);
 }
 
 export function NumberTypeAnnotation() {
@@ -128,17 +132,17 @@ export function TupleTypeAnnotation(node, print) {
 
 export function TypeofTypeAnnotation(node, print) {
   this.push("typeof ");
-  print(node.argument);
+  print.plain(node.argument);
 }
 
 export function TypeAlias(node, print) {
   this.push("type ");
-  print(node.id);
-  print(node.typeParameters);
+  print.plain(node.id);
+  print.plain(node.typeParameters);
   this.space();
   this.push("=");
   this.space();
-  print(node.right);
+  print.plain(node.right);
   this.semicolon();
 }
 
@@ -146,7 +150,7 @@ export function TypeAnnotation(node, print) {
   this.push(":");
   this.space();
   if (node.optional) this.push("?");
-  print(node.typeAnnotation);
+  print.plain(node.typeAnnotation);
 }
 
 export function TypeParameterInstantiation(node, print) {
@@ -183,37 +187,37 @@ export function ObjectTypeAnnotation(node, print) {
 
 export function ObjectTypeCallProperty(node, print) {
   if (node.static) this.push("static ");
-  print(node.value);
+  print.plain(node.value);
 }
 
 export function ObjectTypeIndexer(node, print) {
   if (node.static) this.push("static ");
   this.push("[");
-  print(node.id);
+  print.plain(node.id);
   this.push(":");
   this.space();
-  print(node.key);
+  print.plain(node.key);
   this.push("]");
   this.push(":");
   this.space();
-  print(node.value);
+  print.plain(node.value);
 }
 
 export function ObjectTypeProperty(node, print) {
   if (node.static) this.push("static ");
-  print(node.key);
+  print.plain(node.key);
   if (node.optional) this.push("?");
   if (!t.isFunctionTypeAnnotation(node.value)) {
     this.push(":");
     this.space();
   }
-  print(node.value);
+  print.plain(node.value);
 }
 
 export function QualifiedTypeIdentifier(node, print) {
-  print(node.qualification);
+  print.plain(node.qualification);
   this.push(".");
-  print(node.id);
+  print.plain(node.id);
 }
 
 export function UnionTypeAnnotation(node, print) {
@@ -222,8 +226,8 @@ export function UnionTypeAnnotation(node, print) {
 
 export function TypeCastExpression(node, print) {
   this.push("(");
-  print(node.expression);
-  print(node.typeAnnotation);
+  print.plain(node.expression);
+  print.plain(node.typeAnnotation);
   this.push(")");
 }
 

src/babel/generation/generators/jsx.js

@@ -1,11 +1,10 @@
-import each from "lodash/collection/each";
 import * as t from "../../types";
 
 export function JSXAttribute(node, print) {
-  print(node.name);
+  print.plain(node.name);
   if (node.value) {
     this.push("=");
-    print(node.value);
+    print.plain(node.value);
   }
 }
 
@@ -14,32 +13,32 @@ export function JSXIdentifier(node) {
 }
 
 export function JSXNamespacedName(node, print) {
-  print(node.namespace);
+  print.plain(node.namespace);
   this.push(":");
-  print(node.name);
+  print.plain(node.name);
 }
 
 export function JSXMemberExpression(node, print) {
-  print(node.object);
+  print.plain(node.object);
   this.push(".");
-  print(node.property);
+  print.plain(node.property);
 }
 
 export function JSXSpreadAttribute(node, print) {
   this.push("{...");
-  print(node.argument);
+  print.plain(node.argument);
   this.push("}");
 }
 
 export function JSXExpressionContainer(node, print) {
   this.push("{");
-  print(node.expression);
+  print.plain(node.expression);
   this.push("}");
 }
 
 export function JSXElement(node, print) {
   var open = node.openingElement;
-  print(open);
+  print.plain(open);
   if (open.selfClosing) return;
 
   this.indent();
@@ -47,17 +46,17 @@ export function JSXElement(node, print) {
     if (t.isLiteral(child)) {
       this.push(child.value, true);
     } else {
-      print(child);
+      print.plain(child);
     }
   }
   this.dedent();
 
-  print(node.closingElement);
+  print.plain(node.closingElement);
 }
 
 export function JSXOpeningElement(node, print) {
   this.push("<");
-  print(node.name);
+  print.plain(node.name);
   if (node.attributes.length > 0) {
     this.push(" ");
     print.join(node.attributes, { separator: " " });
@@ -67,7 +66,7 @@ export function JSXOpeningElement(node, print) {
 
 export function JSXClosingElement(node, print) {
   this.push("</");
-  print(node.name);
+  print.plain(node.name);
   this.push(">");
 }
 

src/babel/generation/generators/methods.js

@@ -1,18 +1,18 @@
 import * as t from "../../types";
 
 export function _params(node, print) {
-  print(node.typeParameters);
+  print.plain(node.typeParameters);
   this.push("(");
   print.list(node.params, {
     iterator: (node) =>{
       if (node.optional) this.push("?");
-      print(node.typeAnnotation);
+      print.plain(node.typeAnnotation);
     }
   });
   this.push(")");
 
   if (node.returnType) {
-    print(node.returnType);
+    print.plain(node.returnType);
   }
 }
 
@@ -35,15 +35,15 @@ export function _method(node, print) {
 
   if (node.computed) {
     this.push("[");
-    print(key);
+    print.plain(key);
     this.push("]");
   } else {
-    print(key);
+    print.plain(key);
   }
 
   this._params(value, print);
   this.push(" ");
-  print(value.body);
+  print.plain(value.body);
 }
 
 export function FunctionExpression(node, print) {
@@ -53,14 +53,14 @@ export function FunctionExpression(node, print) {
 
   if (node.id) {
     this.push(" ");
-    print(node.id);
+    print.plain(node.id);
   } else {
     this.space();
   }
 
   this._params(node, print);
   this.space();
-  print(node.body);
+  print.plain(node.body);
 }
 
 export { FunctionExpression as FunctionDeclaration };
@@ -69,7 +69,7 @@ export function ArrowFunctionExpression(node, print) {
   if (node.async) this.push("async ");
 
   if (node.params.length === 1 && t.isIdentifier(node.params[0])) {
-    print(node.params[0]);
+    print.plain(node.params[0]);
   } else {
     this._params(node, print);
   }
@@ -82,7 +82,7 @@ export function ArrowFunctionExpression(node, print) {
     this.push("(");
   }
 
-  print(node.body);
+  print.plain(node.body);
 
   if (bodyNeedsParens) {
     this.push(")");

src/babel/generation/generators/modules.js

@@ -1,43 +1,42 @@
-import each from "lodash/collection/each";
 import * as t from "../../types";
 
 export function ImportSpecifier(node, print) {
-  print(node.imported);
+  print.plain(node.imported);
   if (node.local && node.local.name !== node.imported.name) {
     this.push(" as ");
-    print(node.local);
+    print.plain(node.local);
   }
 }
 
 export function ImportDefaultSpecifier(node, print) {
-  print(node.local);
+  print.plain(node.local);
 }
 
 export function ExportDefaultSpecifier(node, print) {
-  print(node.exported);
+  print.plain(node.exported);
 }
 
 export function ExportSpecifier(node, print) {
-  print(node.local);
+  print.plain(node.local);
   if (node.exported && node.local.name !== node.exported.name) {
     this.push(" as ");
-    print(node.exported);
+    print.plain(node.exported);
   }
 }
 
 export function ExportNamespaceSpecifier(node, print) {
   this.push("* as ");
-  print(node.exported);
+  print.plain(node.exported);
 }
 
 export function ExportAllDeclaration(node, print) {
   this.push("export *");
   if (node.exported) {
     this.push(" as ");
-    print(node.exported);
+    print.plain(node.exported);
   }
   this.push(" from ");
-  print(node.source);
+  print.plain(node.source);
   this.semicolon();
 }
 
@@ -56,14 +55,14 @@ function ExportDeclaration(node, print) {
 
   if (node.declaration) {
     var declar = node.declaration;
-    print(declar);
+    print.plain(declar);
     if (t.isStatement(declar) || t.isFunction(declar) || t.isClass(declar)) return;
   } else {
     var first = specifiers[0];
     var hasSpecial = false;
     if (t.isExportDefaultSpecifier(first) || t.isExportNamespaceSpecifier(first)) {
       hasSpecial = true;
-      print(specifiers.shift());
+      print.plain(specifiers.shift());
       if (specifiers.length) {
         this.push(", ");
       }
@@ -81,7 +80,7 @@ function ExportDeclaration(node, print) {
 
     if (node.source) {
       this.push(" from ");
-      print(node.source);
+      print.plain(node.source);
     }
   }
 
@@ -99,7 +98,7 @@ export function ImportDeclaration(node, print) {
   if (specfiers && specfiers.length) {
     var first = node.specifiers[0];
     if (t.isImportDefaultSpecifier(first) || t.isImportNamespaceSpecifier(first)) {
-      print(node.specifiers.shift());
+      print.plain(node.specifiers.shift());
       if (node.specifiers.length) {
         this.push(", ");
       }
@@ -107,20 +106,20 @@ export function ImportDeclaration(node, print) {
 
     if (node.specifiers.length) {
       this.push("{");
-      this.space()
+      this.space();
       print.join(node.specifiers, { separator: ", " });
-      this.space()
+      this.space();
       this.push("}");
     }
 
     this.push(" from ");
   }
 
-  print(node.source);
+  print.plain(node.source);
   this.semicolon();
 }
 
 export function ImportNamespaceSpecifier(node, print) {
   this.push("* as ");
-  print(node.local);
+  print.plain(node.local);
 }

src/babel/generation/generators/statements.js

@@ -4,7 +4,7 @@ import * as t from "../../types";
 export function WithStatement(node, print) {
   this.keyword("with");
   this.push("(");
-  print(node.object);
+  print.plain(node.object);
   this.push(")");
   print.block(node.body);
 }
@@ -12,7 +12,7 @@ export function WithStatement(node, print) {
 export function IfStatement(node, print) {
   this.keyword("if");
   this.push("(");
-  print(node.test);
+  print.plain(node.test);
   this.push(")");
   this.space();
 
@@ -29,18 +29,18 @@ export function ForStatement(node, print) {
   this.keyword("for");
   this.push("(");
 
-  print(node.init);
+  print.plain(node.init);
   this.push(";");
 
   if (node.test) {
     this.push(" ");
-    print(node.test);
+    print.plain(node.test);
   }
   this.push(";");
 
   if (node.update) {
     this.push(" ");
-    print(node.update);
+    print.plain(node.update);
   }
 
   this.push(")");
@@ -50,7 +50,7 @@ export function ForStatement(node, print) {
 export function WhileStatement(node, print) {
   this.keyword("while");
   this.push("(");
-  print(node.test);
+  print.plain(node.test);
   this.push(")");
   print.block(node.body);
 }
@@ -59,9 +59,9 @@ var buildForXStatement = function (op) {
   return function (node, print) {
     this.keyword("for");
     this.push("(");
-    print(node.left);
+    print.plain(node.left);
     this.push(` ${op} `);
-    print(node.right);
+    print.plain(node.right);
     this.push(")");
     print.block(node.body);
   };
@@ -72,11 +72,11 @@ export var ForOfStatement = buildForXStatement("of");
 
 export function DoWhileStatement(node, print) {
   this.push("do ");
-  print(node.body);
+  print.plain(node.body);
   this.space();
   this.keyword("while");
   this.push("(");
-  print(node.test);
+  print.plain(node.test);
   this.push(");");
 }
 
@@ -87,7 +87,7 @@ var buildLabelStatement = function (prefix, key) {
     var label = node[key || "label"];
     if (label) {
       this.push(" ");
-      print(label);
+      print.plain(label);
     }
 
     this.semicolon();
@@ -99,50 +99,50 @@ export var ReturnStatement   = buildLabelStatement("return", "argument");
 export var BreakStatement    = buildLabelStatement("break");
 
 export function LabeledStatement(node, print) {
-  print(node.label);
+  print.plain(node.label);
   this.push(": ");
-  print(node.body);
+  print.plain(node.body);
 }
 
 export function TryStatement(node, print) {
   this.keyword("try");
-  print(node.block);
+  print.plain(node.block);
   this.space();
 
   // Esprima bug puts the catch clause in a `handlers` array.
   // see https://code.google.com/p/esprima/issues/detail?id=433
   // We run into this from regenerator generated ast.
   if (node.handlers) {
-    print(node.handlers[0]);
+    print.plain(node.handlers[0]);
   } else {
-    print(node.handler);
+    print.plain(node.handler);
   }
 
   if (node.finalizer) {
     this.space();
     this.push("finally ");
-    print(node.finalizer);
+    print.plain(node.finalizer);
   }
 }
 
 export function CatchClause(node, print) {
   this.keyword("catch");
   this.push("(");
-  print(node.param);
+  print.plain(node.param);
   this.push(") ");
-  print(node.body);
+  print.plain(node.body);
 }
 
 export function ThrowStatement(node, print) {
   this.push("throw ");
-  print(node.argument);
+  print.plain(node.argument);
   this.semicolon();
 }
 
 export function SwitchStatement(node, print) {
   this.keyword("switch");
   this.push("(");
-  print(node.discriminant);
+  print.plain(node.discriminant);
   this.push(")");
   this.space();
   this.push("{");
@@ -160,7 +160,7 @@ export function SwitchStatement(node, print) {
 export function SwitchCase(node, print) {
   if (node.test) {
     this.push("case ");
-    print(node.test);
+    print.plain(node.test);
     this.push(":");
   } else {
     this.push("default:");
@@ -207,12 +207,12 @@ export function VariableDeclaration(node, print, parent) {
 }
 
 export function VariableDeclarator(node, print) {
-  print(node.id);
-  print(node.id.typeAnnotation);
+  print.plain(node.id);
+  print.plain(node.id.typeAnnotation);
   if (node.init) {
     this.space();
     this.push("=");
     this.space();
-    print(node.init);
+    print.plain(node.init);
   }
 }

src/babel/generation/generators/template-literals.js

@@ -1,8 +1,6 @@
-import each from "lodash/collection/each";
-
 export function TaggedTemplateExpression(node, print) {
-  print(node.tag);
-  print(node.quasi);
+  print.plain(node.tag);
+  print.plain(node.quasi);
 }
 
 export function TemplateElement(node) {
@@ -16,11 +14,11 @@ export function TemplateLiteral(node, print) {
   var len    = quasis.length;
 
   for (var i = 0; i < len; i++) {
-    print(quasis[i]);
+    print.plain(quasis[i]);
 
     if (i + 1 < len) {
       this.push("${ ");
-      print(node.expressions[i]);
+      print.plain(node.expressions[i]);
       this.push(" }");
     }
   }

src/babel/generation/generators/types.js

@@ -1,4 +1,5 @@
-import each from "lodash/collection/each";
+/* eslint quotes: 0 */
+
 import * as t from "../../types";
 
 export function Identifier(node) {
@@ -7,7 +8,7 @@ export function Identifier(node) {
 
 export function RestElement(node, print) {
   this.push("...");
-  print(node.argument);
+  print.plain(node.argument);
 }
 
 export { RestElement as SpreadElement, RestElement as SpreadProperty };
@@ -36,16 +37,16 @@ export function Property(node, print) {
   } else {
     if (node.computed) {
       this.push("[");
-      print(node.key);
+      print.plain(node.key);
       this.push("]");
     } else {
       // print `({ foo: foo = 5 } = {})` as `({ foo = 5 } = {});`
       if (t.isAssignmentPattern(node.value) && t.isIdentifier(node.key) && node.key.name === node.value.left.name) {
-        print(node.value);
+        print.plain(node.value);
         return;
       }
 
-      print(node.key);
+      print.plain(node.key);
 
       // shorthand!
       if (node.shorthand &&
@@ -58,7 +59,7 @@ export function Property(node, print) {
 
     this.push(":");
     this.space();
-    print(node.value);
+    print.plain(node.value);
   }
 }
 
@@ -79,7 +80,7 @@ export function ArrayExpression(node, print) {
       this.push(",");
     } else {
       if (i > 0) this.push(" ");
-      print(elem);
+      print.plain(elem);
       if (i < len - 1) this.push(",");
     }
   }

src/babel/generation/index.js

@@ -1,5 +1,6 @@
 import detectIndent from "detect-indent";
 import Whitespace from "./whitespace";
+import NodePrinter from "./node/printer";
 import repeating from "repeating";
 import SourceMap from "./source-map";
 import Position from "./position";
@@ -20,7 +21,7 @@ class CodeGenerator {
     this.opts     = opts;
     this.ast      = ast;
 
-    this.whitespace = new Whitespace(this.tokens, this.comments, this.format);
+    this.whitespace = new Whitespace(this.tokens);
     this.position   = new Position;
     this.map        = new SourceMap(this.position, opts, code);
     this.buffer     = new Buffer(this.position, this.format);
@@ -67,7 +68,6 @@ class CodeGenerator {
     for (var i = 0; i < tokens.length; i++) {
       var token = tokens[i];
       if (token.type.label !== "string") continue;
-      if (checked >= 3) continue;
 
       var raw = code.slice(token.start, token.end);
       if (raw[0] === "'") {
@@ -77,6 +77,7 @@ class CodeGenerator {
       }
 
       checked++;
+      if (checked >= 3) break;
     }
 
     if (occurences.single > occurences.double) {
@@ -120,33 +121,7 @@ class CodeGenerator {
   }
 
   buildPrint(parent) {
-    var print = (node, opts) => {
-      return this.print(node, parent, opts);
-    };
-
-    print.sequence = (nodes, opts = {}) => {
-      opts.statement = true;
-      return this.printJoin(print, nodes, opts);
-    };
-
-    print.join = (nodes, opts) => {
-      return this.printJoin(print, nodes, opts);
-    };
-
-    print.list = function (items, opts = {}) {
-      if (opts.separator == null) opts.separator = ", ";
-      print.join(items, opts);
-    };
-
-    print.block = (node) => {
-      return this.printBlock(print, node);
-    };
-
-    print.indentOnComments = (node) => {
-      return this.printAndIndentOnComments(print, node);
-    };
-
-    return print;
+    return new NodePrinter(this, parent);
   }
 
   catchUp(node, parent, leftParenPrinted) {
@@ -166,6 +141,36 @@ class CodeGenerator {
     return false;
   }
 
+  _printNewline(leading, node, parent, opts) {
+    if (!opts.statement && !n.isUserWhitespacable(node, parent)) {
+      return;
+    }
+
+    var lines = 0;
+
+    if (node.start != null && !node._ignoreUserWhitespace) {
+      // user node
+      if (leading) {
+        lines = this.whitespace.getNewlinesBefore(node);
+      } else {
+        lines = this.whitespace.getNewlinesAfter(node);
+      }
+    } else {
+      // generated node
+      if (!leading) lines++; // always include at least a single line after
+      if (opts.addNewlines) lines += opts.addNewlines(leading, node) || 0;
+
+      var needs = n.needsWhitespaceAfter;
+      if (leading) needs = n.needsWhitespaceBefore;
+      if (needs(node, parent)) lines++;
+
+      // generated nodes can't add starting file whitespace
+      if (!this.buffer.buf) lines = 0;
+    }
+
+    this.newline(lines);
+  }
+
   print(node, parent, opts = {}) {
     if (!node) return;
 
@@ -178,36 +183,6 @@ class CodeGenerator {
       this.format.concise = true;
     }
 
-    var newline = (leading) => {
-      if (!opts.statement && !n.isUserWhitespacable(node, parent)) {
-        return;
-      }
-
-      var lines = 0;
-
-      if (node.start != null && !node._ignoreUserWhitespace) {
-        // user node
-        if (leading) {
-          lines = this.whitespace.getNewlinesBefore(node);
-        } else {
-          lines = this.whitespace.getNewlinesAfter(node);
-        }
-      } else {
-        // generated node
-        if (!leading) lines++; // always include at least a single line after
-        if (opts.addNewlines) lines += opts.addNewlines(leading, node) || 0;
-
-        var needs = n.needsWhitespaceAfter;
-        if (leading) needs = n.needsWhitespaceBefore;
-        if (needs(node, parent)) lines++;
-
-        // generated nodes can't add starting file whitespace
-        if (!this.buffer.buf) lines = 0;
-      }
-
-      this.newline(lines);
-    };
-
     if (this[node.type]) {
       var needsNoLineTermParens = n.needsParensNoLineTerminator(node, parent);
       var needsParens           = needsNoLineTermParens || n.needsParens(node, parent);
@@ -219,7 +194,7 @@ class CodeGenerator {
 
       var needsParensFromCatchup = this.catchUp(node, parent, needsParens);
 
-      newline(true);
+      this._printNewline(true, node, parent, opts);
 
       if (opts.before) opts.before();
       this.map.mark(node, "start");
@@ -237,7 +212,7 @@ class CodeGenerator {
 
       this.format.concise = oldConcise;
 
-      newline(false);
+      this._printNewline(false, node, parent, opts);
 
       this.printTrailingComments(node, parent);
     } else {
@@ -252,21 +227,23 @@ class CodeGenerator {
 
     if (opts.indent) this.indent();
 
+    var printOpts = {
+      statement: opts.statement,
+      addNewlines: opts.addNewlines,
+      after: () => {
+        if (opts.iterator) {
+          opts.iterator(node, i);
+        }
+
+        if (opts.separator && i < len - 1) {
+          this.push(opts.separator);
+        }
+      }
+    };
+
     for (var i = 0; i < nodes.length; i++) {
       var node = nodes[i];
-      print(node, {
-        statement: opts.statement,
-        addNewlines: opts.addNewlines,
-        after: () => {
-          if (opts.iterator) {
-            opts.iterator(node, i);
-          }
-
-          if (opts.separator && i < len - 1) {
-            this.push(opts.separator);
-          }
-        }
-      });
+      print.plain(node, printOpts);
     }
 
     if (opts.indent) this.dedent();
@@ -275,7 +252,7 @@ class CodeGenerator {
   printAndIndentOnComments(print, node) {
     var indent = !!node.leadingComments;
     if (indent) this.indent();
-    print(node);
+    print.plain(node);
     if (indent) this.dedent();
   }
 
@@ -284,13 +261,13 @@ class CodeGenerator {
       this.semicolon();
     } else {
       this.push(" ");
-      print(node);
+      print.plain(node);
     }
   }
 
   generateComment(comment) {
     var val = comment.value;
-    if (comment.type === "Line") {
+    if (comment.type === "CommentLine") {
       val = `//${val}`;
     } else {
       val = `/*${val}*/`;
@@ -318,7 +295,7 @@ class CodeGenerator {
       nodes.push(node.argument);
     }
 
-    for (var node of (nodes: Array)) {
+    for (let node of (nodes: Array)) {
       comments = comments.concat(this._getComments(key, node));
     }
 
@@ -366,7 +343,7 @@ class CodeGenerator {
       }
 
       //
-      if (comment.type === "Block" && this.format.indent.adjustMultilineComment) {
+      if (comment.type === "CommentBlock" && this.format.indent.adjustMultilineComment) {
         var offset = comment.loc.start.column;
         if (offset) {
           var newlineRegex = new RegExp("\\n\\s{1," + offset + "}", "g");
@@ -383,7 +360,7 @@ class CodeGenerator {
 
       // force a newline for line comments when retainLines is set in case the next printed node
       // doesn't catch up
-      if (this.format.retainLines && comment.type === "Line") {
+      if (this.format.retainLines && comment.type === "CommentLine") {
         val += "\n";
       }
 

src/babel/generation/node/printer.js

@@ -0,0 +1,32 @@
+export default class NodePrinter {
+  constructor(generator, parent) {
+    this.generator = generator;
+    this.parent = parent;
+  }
+
+  plain(node, opts) {
+    return this.generator.print(node, this.parent, opts);
+  }
+
+  sequence(nodes, opts = {}) {
+    opts.statement = true;
+    return this.generator.printJoin(this, nodes, opts);
+  }
+
+  join(nodes, opts) {
+    return this.generator.printJoin(this, nodes, opts);
+  }
+
+  list(items, opts = {}) {
+    if (opts.separator == null) opts.separator = ", ";
+    return this.join(items, opts);
+  }
+
+  block(node) {
+    return this.generator.printBlock(this, node);
+  }
+
+  indentOnComments(node) {
+    return this.generator.printAndIndentOnComments(this, node);
+  }
+}

src/babel/generation/whitespace.js

@@ -1,5 +1,3 @@
-import sortBy from "lodash/collection/sortBy";
-
 /**
  * Returns `i`th number from `base`, continuing from 0 when `max` is reached.
  * Useful for shifting `for` loop by a fixed number but going over all items.
@@ -21,8 +19,8 @@ function getLookupIndex(i, base, max) {
 }
 
 export default class Whitespace {
-  constructor(tokens, comments) {
-    this.tokens = sortBy(tokens.concat(comments), "start");
+  constructor(tokens) {
+    this.tokens = tokens;
     this.used   = {};
 
     // Profiling this code shows that while generator passes over it, indexes
@@ -40,12 +38,11 @@ export default class Whitespace {
     var startToken;
     var endToken;
     var tokens = this.tokens;
-    var token;
 
     for (var j = 0; j < tokens.length; j++) {
       // optimize for forward traversal by shifting for loop index
       var i = getLookupIndex(j, this._lastFoundIndex, this.tokens.length);
-      token = tokens[i];
+      var token = tokens[i];
 
       // this is the token this node starts with
       if (node.start === token.start) {
@@ -64,17 +61,17 @@ export default class Whitespace {
     var startToken;
     var endToken;
     var tokens = this.tokens;
-    var token;
 
     for (var j = 0; j < tokens.length; j++) {
       // optimize for forward traversal by shifting for loop index
       var i = getLookupIndex(j, this._lastFoundIndex, this.tokens.length);
-      token = tokens[i];
+      var token = tokens[i];
 
       // this is the token this node ends with
       if (node.end === token.end) {
         startToken = token;
         endToken = tokens[i + 1];
+        if (endToken.type.label === ",") endToken = tokens[i + 2];
 
         this._lastFoundIndex = i;
         break;
@@ -85,7 +82,7 @@ export default class Whitespace {
       return 1;
     } else {
       var lines = this.getNewlinesBetween(startToken, endToken);
-      if (node.type === "Line" && !lines) {
+      if (node.type === "CommentLine" && !lines) {
         // line comment
         return 1;
       } else {

src/babel/helpers/code-frame.js

@@ -85,4 +85,4 @@ export default function (lines: number, lineNumber: number, colNumber: number, o
       params.before = params.before.replace(/^./, ">");
     }
   }).join("\n");
-};
+}

src/babel/helpers/normalize-ast.js

@@ -6,4 +6,4 @@ export default function (ast, comments, tokens) {
   } else {
     throw new Error("Not a valid ast?");
   }
-};
+}

src/babel/helpers/object.js

@@ -1,3 +1,3 @@
 export default function () {
   return Object.create(null);
-};
+}

src/babel/helpers/parse.js

@@ -3,8 +3,9 @@ import estraverse from "estraverse";
 import * as acorn from "../../acorn";
 
 export default function (code, opts = {}) {
-  var comments = [];
-  var tokens   = [];
+  var commentsAndTokens = [];
+  var comments          = [];
+  var tokens            = [];
 
   var parseOpts = {
     allowImportExportEverywhere: opts.looseModules,
@@ -14,13 +15,31 @@ export default function (code, opts = {}) {
     strictMode:                  opts.strictMode,
     sourceType:                  opts.sourceType,
     locations:                   true,
-    onComment:                   comments,
     features:                    opts.features || {},
     plugins:                     opts.plugins || {},
     onToken:                     tokens,
     ranges:                      true
   };
 
+  parseOpts.onToken = function (token) {
+    tokens.push(token);
+    commentsAndTokens.push(token);
+  };
+
+  parseOpts.onComment = function (block, text, start, end, startLoc, endLoc) {
+    var comment = {
+      type: block ? "CommentBlock" : "CommentLine",
+      value: text,
+      start: start,
+      end: end,
+      loc: new acorn.SourceLocation(this, startLoc, endLoc),
+      range: [start, end]
+    };
+
+    commentsAndTokens.push(comment);
+    comments.push(comment);
+  };
+
   if (opts.nonStandard) {
     parseOpts.plugins.jsx = true;
     parseOpts.plugins.flow = true;
@@ -28,6 +47,6 @@ export default function (code, opts = {}) {
 
   var ast = acorn.parse(code, parseOpts);
   estraverse.attachComments(ast, comments, tokens);
-  ast = normalizeAst(ast, comments, tokens);
+  ast = normalizeAst(ast, comments, commentsAndTokens);
   return ast;
 }

src/babel/tools/build-external-helpers.js

@@ -83,4 +83,4 @@ export default function (whitelist, outputType = "global") {
   }
 
   return generator(tree).code;
-};
+}

src/babel/tools/resolve-rc.js

@@ -56,4 +56,4 @@ export default function (loc, opts = {}) {
   }
 
   return opts;
-};
+}

src/babel/transformation/file/index.js

@@ -3,13 +3,12 @@ import * as optionParsers from "./option-parsers";
 import moduleFormatters from "../modules";
 import PluginManager from "./plugin-manager";
 import shebangRegex from "shebang-regex";
-import TraversalPath from "../../traversal/path";
+import NodePath from "../../traversal/path";
 import Transformer from "../transformer";
 import isFunction from "lodash/lang/isFunction";
 import isAbsolute from "path-is-absolute";
 import resolveRc from "../../tools/resolve-rc";
 import sourceMap from "source-map";
-import transform from "./../index";
 import generate from "../../generation";
 import codeFrame from "../../helpers/code-frame";
 import defaults from "lodash/object/defaults";
@@ -18,12 +17,10 @@ import traverse from "../../traversal";
 import assign from "lodash/object/assign";
 import Logger from "./logger";
 import parse from "../../helpers/parse";
-import Scope from "../../traversal/scope";
 import merge from "../../helpers/merge";
 import slash from "slash";
 import clone from "lodash/lang/clone";
 import * as util from  "../../util";
-import * as api from  "../../api/node";
 import path from "path";
 import * as t from "../../types";
 
@@ -195,7 +192,7 @@ export default class File {
     // build internal transformers
     for (var key in this.pipeline.transformers) {
       var transformer = this.pipeline.transformers[key];
-      var pass = transformers[key] = transformer.buildPass(file);
+      let pass = transformers[key] = transformer.buildPass(file);
 
       if (pass.canTransform()) {
         stack.push(pass);
@@ -228,7 +225,7 @@ export default class File {
     this.uncollapsedTransformerStack = stack = stack.concat(secondaryStack);
 
     // build dependency graph
-    for (var pass of (stack: Array)) {
+    for (let pass of (stack: Array)) {
       for (var dep of (pass.transformer.dependencies: Array)) {
         this.transformerDependencies[dep] = pass.key;
       }
@@ -268,7 +265,6 @@ export default class File {
       }
       var visitor = traverse.visitors.merge(visitors);
       var mergeTransformer = new Transformer(group, visitor);
-      //console.log(mergeTransformer);
       stack.push(mergeTransformer.buildPass(this));
     }
 
@@ -334,7 +330,7 @@ export default class File {
     if (comment) {
       node.leadingComments = node.leadingComments || [];
       node.leadingComments.push({
-        type: "Line",
+        type: "CommentLine",
         value: " " + comment
       });
     }
@@ -348,8 +344,6 @@ export default class File {
       throw new ReferenceError(`Unknown helper ${name}`);
     }
 
-    var program = this.ast.program;
-
     var declar = this.declarations[name];
     if (declar) return declar;
 
@@ -390,9 +384,14 @@ export default class File {
   }
 
   errorWithNode(node, msg, Error = SyntaxError) {
-    var loc = node.loc.start;
-    var err = new Error(`Line ${loc.line}: ${msg}`);
-    err.loc = loc;
+    var err;
+    if (node.loc) {
+      var loc = node.loc.start;
+      err = new Error(`Line ${loc.line}: ${msg}`);
+      err.loc = loc;
+    } else {
+      err = new Error("There's been an error on a dynamic node. This is almost certainly an internal error. Please report it.");
+    }
     return err;
   }
 
@@ -410,7 +409,7 @@ export default class File {
       outputMapGenerator.applySourceMap(inputMapConsumer);
 
       var mergedMap = outputMapGenerator.toJSON();
-      mergedMap.sources = inputMap.sources
+      mergedMap.sources = inputMap.sources;
       mergedMap.file    = inputMap.file;
       return mergedMap;
     }
@@ -420,6 +419,10 @@ export default class File {
 
 
   getModuleFormatter(type: string) {
+    if (isFunction(type) || !moduleFormatters[type]) {
+      this.log.deprecate("Custom module formatters are deprecated and will be removed in the next major. Please use Babel plugins instead.");
+    }
+
     var ModuleFormatter = isFunction(type) ? type : moduleFormatters[type];
 
     if (!ModuleFormatter) {
@@ -463,7 +466,12 @@ export default class File {
   }
 
   _addAst(ast) {
-    this.path  = TraversalPath.get(null, ast, ast, "program", this).setContext(null, this);
+    this.path  = NodePath.get({
+      parentPath: null,
+      parent: ast,
+      container: ast,
+      key: "program"
+    }).setContext(null, this);
     this.scope = this.path.scope;
     this.ast   = ast;
   }
@@ -478,32 +486,30 @@ export default class File {
     if (modFormatter.init && this.transformers["es6.modules"].canTransform()) {
       modFormatter.init();
     }
+    this.populateModuleMetadata();
     this.log.debug("End module formatter init");
+  }
 
+  populateModuleMetadata() {
+    var modules = {};
+    this.metadata.modules = modules;
+  }
+
+  transform() {
     this.call("pre");
     for (var pass of (this.transformerStack: Array)) {
       pass.transform();
     }
     this.call("post");
+
+    return this.generate();
   }
 
   wrap(code, callback) {
     code = code + "";
 
     try {
-      if (this.shouldIgnore()) {
-        return {
-          metadata: this.metadata,
-          ignored:  true,
-          code:     code,
-          map:      null,
-          ast:      null
-        };
-      }
-
-      callback();
-
-      return this.generate();
+      return callback();
     } catch (err) {
       if (err._babel) {
         throw err;
@@ -532,15 +538,15 @@ export default class File {
     }
   }
 
-  addCode(code: string, parseCode?) {
+  addCode(code: string) {
     code = (code || "") + "";
     code = this.parseInputSourceMap(code);
     this.code = code;
+  }
 
-    if (parseCode) {
-      this.parseShebang();
-      this.addAst(this.parse(this.code));
-    }
+  parseCode() {
+    this.parseShebang();
+    this.addAst(this.parse(this.code));
   }
 
   shouldIgnore() {
@@ -577,28 +583,37 @@ export default class File {
     }
   }
 
-  generate(): {
-    usedHelpers?: Array<string>;
-    code: string;
-    map?: Object;
-    ast?: Object;
-  } {
-    var opts = this.opts;
-    var ast  = this.ast;
-
+  makeResult({ code, map = null, ast, ignored }) {
     var result = {
-      metadata: this.metadata,
-      code:     "",
-      map:      null,
-      ast:      null
+      metadata: null,
+      ignored:  !!ignored,
+      code:     null,
+      ast:      null,
+      map:      map
     };
 
-    if (this.opts.metadataUsedHelpers) {
+    if (this.opts.code) {
+      result.code = code;
+    }
+
+    if (this.opts.ast) {
+      result.ast = ast;
+    }
+
+    if (this.opts.metadata) {
+      result.metadata = this.metadata;
       result.metadata.usedHelpers = Object.keys(this.usedHelpers);
     }
 
-    if (opts.ast) result.ast = ast;
-    if (!opts.code) return result;
+    return result;
+  }
+
+  generate() {
+    var opts = this.opts;
+    var ast  = this.ast;
+
+    var result = { ast };
+    if (!opts.code) return this.makeResult(result);
 
     this.log.debug("Generation start");
 
@@ -625,6 +640,6 @@ export default class File {
       result.map = null;
     }
 
-    return result;
+    return this.makeResult(result);
   }
 }

src/babel/transformation/file/logger.js

@@ -1,3 +1,4 @@
+import type File from "./index";
 import buildDebug from "debug/node";
 
 var verboseDebug = buildDebug("babel:verbose");
@@ -15,6 +16,10 @@ export default class Logger {
     return parts;
   }
 
+  warn(msg) {
+    console.warn(this._buildMessage(msg));
+  }
+
   error(msg: string, Constructor = Error) {
     throw new Constructor(this._buildMessage(msg));
   }

src/babel/transformation/file/options.json

@@ -47,7 +47,8 @@
   },
 
   "experimental": {
-    "deprecated": "use `--stage 0`/`{ stage: 0 }` instead"
+    "description": "allow use of experimental transformers",
+    "default": false
   },
 
   "highlightCode": {
@@ -139,6 +140,12 @@
     "type": "boolean"
   },
 
+  "metadata": {
+    "hidden": true,
+    "default": true,
+    "type": "boolean"
+  },
+
   "ast": {
     "hidden": true,
     "default": true,
@@ -179,6 +186,7 @@
   },
 
   "metadataUsedHelpers": {
+    "deprecated": "Not required anymore as this is enabled by default",
     "type": "boolean",
     "default": false,
     "hidden": true

src/babel/transformation/file/plugin-manager.js

@@ -37,9 +37,10 @@ export default class PluginManager {
 
     var loc = util.resolveRelative(`babel-plugin-${name}`) || util.resolveRelative(name);
     if (loc) {
+      var plugin = require(loc);
       return {
         position: position,
-        plugin:   require(loc)
+        plugin:   plugin.default || plugin
       };
     } else {
       throw new ReferenceError(messages.get("pluginUnknown", name));

src/babel/transformation/helpers/build-binary-assignment-operator-transformer.js

@@ -44,4 +44,4 @@ export default function (opts) {
   };
 
   return exports;
-};
+}

src/babel/transformation/helpers/build-conditional-assignment-operator-transformer.js

@@ -42,4 +42,4 @@ export default function (exports, opts) {
 
     return nodes;
   };
-};
+}

src/babel/transformation/helpers/build-react-transformer.js

@@ -10,7 +10,7 @@ import * as react from "./react";
 import * as t from "../../types";
 
 export default function (exports, opts) {
-  exports.JSXIdentifier = function (node, parent) {
+  exports.JSXIdentifier = function (node) {
     if (node.name === "this" && this.isReferenced()) {
       return t.thisExpression();
     } else if (esutils.keyword.isIdentifierNameES6(node.name)) {
@@ -20,7 +20,7 @@ export default function (exports, opts) {
     }
   };
 
-  exports.JSXNamespacedName = function (node, parent, scope, file) {
+  exports.JSXNamespacedName = function () {
     throw this.errorWithNode(messages.get("JSXNamespacedTags"));
   };
 
@@ -161,7 +161,8 @@ export default function (exports, opts) {
 
     for (var i = 0; i < props.length; i++) {
       var prop = props[i];
-      if (t.isIdentifier(prop.key, { name: "displayName" })) {
+      var key = t.toComputedKey(prop);
+      if (t.isLiteral(key, { value: "displayName" })) {
         safe = false;
         break;
       }
@@ -202,4 +203,4 @@ export default function (exports, opts) {
       addDisplayName(left.name, right);
     }
   };
-};
+}

src/babel/transformation/helpers/call-delegate.js

@@ -1,4 +1,3 @@
-import traverse from "../../traversal";
 import * as t from "../../types";
 
 var visitor = {
@@ -7,10 +6,10 @@ var visitor = {
       state.found = true;
       this.stop();
     }
+  },
 
-    if (this.isFunction()) {
-      this.skip();
-    }
+  Function() {
+    this.skip();
   }
 };
 

src/babel/transformation/helpers/define-map.js

@@ -1,5 +1,3 @@
-import cloneDeep from "lodash/lang/cloneDeep";
-import traverse from "../../traversal";
 import each from "lodash/collection/each";
 import has from "lodash/object/has";
 import * as t from "../../types";

src/babel/transformation/helpers/explode-assignable-expression.js

@@ -68,4 +68,4 @@ export default function (node, nodes, file, scope, allowedSingleIdent) {
     uid: uid,
     ref: ref
   };
-};
+}

src/babel/transformation/helpers/get-function-arity.js

@@ -6,4 +6,4 @@ export default function (node) {
     if (!t.isAssignmentPattern(node.params[i])) lastNonDefault = i + 1;
   }
   return lastNonDefault;
-};
+}

src/babel/transformation/helpers/name-method.js

@@ -2,25 +2,35 @@ import getFunctionArity from "./get-function-arity";
 import * as util from  "../../util";
 import * as t from "../../types";
 
+function visitIdentifier(context, node, scope, state) {
+  // check if this node matches our function id
+  if (node.name !== state.name) return;
+
+  // check that we don't have a local variable declared as that removes the need
+  // for the wrapper
+  var localDeclar = scope.getBindingIdentifier(state.name);
+  if (localDeclar !== state.outerDeclar) return;
+
+  state.selfReference = true;
+  context.stop();
+}
+
 var visitor = {
-  enter(node, parent, scope, state) {
-    // check if this node is a referenced identifier that matches the same as our
-    // function id
-    if (!this.isReferencedIdentifier({ name: state.name })) return;
+  ReferencedIdentifier(node, parent, scope, state) {
+    visitIdentifier(this, node, scope, state);
+  },
 
-    // check that we don't have a local variable declared as that removes the need
-    // for the wrapper
-    var localDeclar = scope.getBindingIdentifier(state.name);
-    if (localDeclar !== state.outerDeclar) return;
-
-    state.selfReference = true;
-    this.stop();
+  AssignmentExpression(node, parent, scope, state) {
+    var ids = this.getBindingIdentifiers();
+    for (var name in ids) {
+      visitIdentifier(this, ids[name], scope, state);
+    }
   }
 };
 
 var wrap = function (state, method, id, scope) {
   if (state.selfReference) {
-    if (scope.hasBinding(id.name)) {
+    if (scope.hasBinding(id.name) && !scope.hasGlobal(id.name)) {
       // we can just munge the local binding
       scope.rename(id.name);
     } else {
@@ -46,6 +56,7 @@ var wrap = function (state, method, id, scope) {
   }
 
   method.id = id;
+  scope.getProgramParent().references[id.name] = true;
 };
 
 var visit = function (node, name, scope) {

src/babel/transformation/helpers/react.js

@@ -1,4 +1,3 @@
-import isString from "lodash/lang/isString";
 import * as t from "../../types";
 
 var isCreateClassCallExpression = t.buildMatchMemberExpression("React.createClass");
@@ -26,10 +25,6 @@ export function isCompatTag(tagName) {
   return tagName && /^[a-z]|\-/.test(tagName);
 }
 
-function isStringLiteral(node) {
-  return t.isLiteral(node) && isString(node.value);
-}
-
 function cleanJSXElementLiteralChild(child, args) {
   var lines = child.value.split(/\r\n|\n|\r/);
 

src/babel/transformation/helpers/remap-async-to-generator.js

@@ -1,25 +1,25 @@
 import * as t from "../../types";
 
 var awaitVisitor = {
-  enter(node, parent, scope, state) {
-    if (t.isFunction(node)) this.skip();
+  Function() {
+    this.skip();
+  },
 
-    if (t.isAwaitExpression(node)) {
-      node.type = "YieldExpression";
+  AwaitExpression(node) {
+    node.type = "YieldExpression";
 
-      if (node.all) {
-        // await* foo; -> yield Promise.all(foo);
-        node.all = false;
-        node.argument = t.callExpression(t.memberExpression(t.identifier("Promise"), t.identifier("all")), [node.argument]);
-      }
+    if (node.all) {
+      // await* foo; -> yield Promise.all(foo);
+      node.all = false;
+      node.argument = t.callExpression(t.memberExpression(t.identifier("Promise"), t.identifier("all")), [node.argument]);
     }
   }
 };
 
 var referenceVisitor = {
-  enter(node, parent, scope, state) {
+  ReferencedIdentifier(node, parent, scope, state) {
     var name = state.id.name;
-    if (this.isReferencedIdentifier({ name: name }) && scope.bindingIdentifierEquals(name, state.id)) {
+    if (node.name === name && scope.bindingIdentifierEquals(name, state.id)) {
       return state.ref = state.ref || scope.generateUidIdentifier(name);
     }
   }
@@ -55,4 +55,4 @@ export default function (node, callId, scope) {
 
     return call;
   }
-};
+}

src/babel/transformation/helpers/replace-supers.js

@@ -1,3 +1,4 @@
+import type NodePath from "../../traversal/path";
 import * as messages from "../../messages";
 import * as t from "../../types";
 
@@ -130,7 +131,7 @@ export default class ReplaceSupers {
    * Description
    */
 
-  traverseLevel(path: TraversalPath, topLevel: boolean) {
+  traverseLevel(path: NodePath, topLevel: boolean) {
     var state = { self: this, topLevel: topLevel };
     path.traverse(visitor, state);
   }
@@ -192,7 +193,7 @@ export default class ReplaceSupers {
    * Description
    */
 
-  looseHandle(path: TraversalPath, getThisReference: Function) {
+  looseHandle(path: NodePath, getThisReference: Function) {
     var node = path.node;
     if (path.isSuper()) {
       return this.getLooseSuperProperty(node, path.parent);
@@ -234,7 +235,7 @@ export default class ReplaceSupers {
    * Description
    */
 
-  specHandle(path: TraversalPath, getThisReference: Function) {
+  specHandle(path: NodePath, getThisReference: Function) {
     var methodNode = this.methodNode;
     var property;
     var computed;
@@ -274,7 +275,7 @@ export default class ReplaceSupers {
       property = node.property;
       computed = node.computed;
     } else if (t.isUpdateExpression(node) && isMemberExpressionSuper(node.argument)) {
-      var binary = t.binaryExpression(node.operator[0], node.argument, t.literal(1))
+      var binary = t.binaryExpression(node.operator[0], node.argument, t.literal(1));
       if (node.prefix) {
         // ++super.foo; -> super.foo += 1;
         return this.specHandleAssignmentExpression(null, path, binary, getThisReference);

src/babel/transformation/helpers/strict.js

@@ -1,19 +0,0 @@
-import * as t from "../../types";
-
-export function has(node) {
-  var first = node.body[0];
-  return t.isExpressionStatement(first) && t.isLiteral(first.expression, { value: "use strict" });
-}
-
-export function wrap(node, callback) {
-  var useStrictNode;
-  if (has(node)) {
-    useStrictNode = node.body.shift();
-  }
-
-  callback();
-
-  if (useStrictNode) {
-    node.body.unshift(useStrictNode);
-  }
-}

src/babel/transformation/modules/_default.js

@@ -1,12 +1,11 @@
 import * as messages from "../../messages";
-import traverse from "../../traversal";
 import extend from "lodash/object/extend";
 import object from "../../helpers/object";
 import * as util from  "../../util";
 import * as t from "../../types";
 
 var remapVisitor = {
-  enter(node, parent, scope, formatter) {
+  enter(node) {
     if (node._skipModulesRemap) {
       return this.skip();
     }
@@ -69,46 +68,50 @@ var remapVisitor = {
   }
 };
 
-var importsVisitor = {
-  ImportDeclaration: {
-    enter(node, parent, scope, formatter) {
-      formatter.hasLocalImports = true;
-      extend(formatter.localImports, this.getBindingIdentifiers());
+var metadataVisitor = {
+  ModuleDeclaration(node, parent, scope, formatter) {
+    if (node.source) {
+      node.source.value = formatter.file.resolveModuleSource(node.source.value);
     }
-  }
-};
+  },
 
-var exportsVisitor = {
-  ExportDeclaration: {
-    enter(node, parent, scope, formatter) {
-      formatter.hasLocalExports = true;
+  ImportDeclaration(node, parent, scope, formatter) {
+    formatter.hasLocalImports = true;
+    extend(formatter.localImports, this.getBindingIdentifiers());
+  },
 
-      var declar = this.get("declaration");
-      if (declar.isStatement()) {
-        var bindings = declar.getBindingIdentifiers()
-        for (var name in bindings) {
-          var binding = bindings[name];
-          formatter._addExport(name, binding);
-        }
-      }
+  ExportDeclaration(node, parent, scope, formatter) {
+    formatter.hasLocalExports = true;
 
-      if (this.isExportNamedDeclaration() && node.specifiers) {
-        for (var i = 0; i < node.specifiers.length; i++) {
-          var specifier = node.specifiers[i];
-          var local = specifier.local;
-          if (!local) continue;
-
-          formatter._addExport(local.name, specifier.exported);
-        }
-      }
-
-      if (!t.isExportDefaultDeclaration(node)) {
-        var onlyDefault = node.specifiers && node.specifiers.length === 1 && t.isSpecifierDefault(node.specifiers[0]);
-        if (!onlyDefault) {
-          formatter.hasNonDefaultExports = true;
-        }
+    var declar = this.get("declaration");
+    if (declar.isStatement()) {
+      var bindings = declar.getBindingIdentifiers();
+      for (var name in bindings) {
+        var binding = bindings[name];
+        formatter._addExport(name, binding);
       }
     }
+
+    if (this.isExportNamedDeclaration() && node.specifiers) {
+      for (var i = 0; i < node.specifiers.length; i++) {
+        var specifier = node.specifiers[i];
+        var local = specifier.local;
+        if (!local) continue;
+
+        formatter._addExport(local.name, specifier.exported);
+      }
+    }
+
+    if (!t.isExportDefaultDeclaration(node)) {
+      var onlyDefault = node.specifiers && node.specifiers.length === 1 && t.isSpecifierDefault(node.specifiers[0]);
+      if (!onlyDefault) {
+        formatter.hasNonDefaultExports = true;
+      }
+    }
+  },
+
+  Scope() {
+    this.skip();
   }
 };
 
@@ -128,8 +131,7 @@ export default class DefaultFormatter {
     this.localExports = object();
     this.localImports = object();
 
-    this.getLocalExports();
-    this.getLocalImports();
+    this.getMetadata();
   }
 
   isModuleType(node, type) {
@@ -145,12 +147,15 @@ export default class DefaultFormatter {
     return (t.isExportDefaultDeclaration(node) || t.isSpecifierDefault(node)) && !this.noInteropRequireExport && !this.hasNonDefaultExports;
   }
 
-  getLocalExports() {
-    this.file.path.traverse(exportsVisitor, this);
-  }
-
-  getLocalImports() {
-    this.file.path.traverse(importsVisitor, this);
+  getMetadata() {
+    var has = false;
+    for (var node of (this.file.ast.program.body: Array)) {
+      if (t.isModuleDeclaration(node)) {
+        has = true;
+        break;
+      }
+    }
+    if (has) this.file.path.traverse(metadataVisitor, this);
   }
 
   remapAssignments() {

src/babel/transformation/modules/_strict.js

@@ -10,4 +10,4 @@ export default function (Parent) {
   util.inherits(Constructor, Parent);
 
   return Constructor;
-};
+}

src/babel/transformation/modules/common.js

@@ -1,5 +1,4 @@
 import DefaultFormatter from "./_default";
-import includes from "lodash/collection/includes";
 import * as util from  "../../util";
 import * as t from "../../types";
 
@@ -84,7 +83,7 @@ export default class CommonJSFormatter extends DefaultFormatter {
     }, true));
   }
 
-  exportSpecifier(specifier, node, nodes) {
+  exportSpecifier(specifier) {
     if (this.doDefaultExportInterop(specifier)) {
       this.hasDefaultOnlyExport = true;
     }
@@ -92,7 +91,7 @@ export default class CommonJSFormatter extends DefaultFormatter {
     DefaultFormatter.prototype.exportSpecifier.apply(this, arguments);
   }
 
-  exportDeclaration(node, nodes) {
+  exportDeclaration(node) {
     if (this.doDefaultExportInterop(node)) {
       this.hasDefaultOnlyExport = true;
     }
@@ -101,8 +100,6 @@ export default class CommonJSFormatter extends DefaultFormatter {
   }
 
   _getExternalReference(node, nodes) {
-    var source = node.source.value;
-
     var call = t.callExpression(t.identifier("require"), [node.source]);
     var uid;
 

src/babel/transformation/modules/system.js

@@ -3,7 +3,6 @@ import AMDFormatter from "./amd";
 import object from  "../../helpers/object";
 import * as util from  "../../util";
 import last from "lodash/array/last";
-import each from "lodash/collection/each";
 import map from "lodash/collection/map";
 import * as t from "../../types";
 
@@ -45,12 +44,14 @@ var hoistVariablesVisitor = {
 };
 
 var hoistFunctionsVisitor = {
-  enter(node, parent, scope, state) {
-    if (t.isFunction(node)) this.skip();
+  Function() {
+    this.skip();
+  },
 
+  enter(node, parent, scope, state) {
     if (t.isFunctionDeclaration(node) || state.formatter._canHoist(node)) {
       state.handlerBody.push(node);
-      this.remove();
+      this.dangerouslyRemove();
     }
   }
 };
@@ -69,7 +70,7 @@ var runnerSettersVisitor = {
         state.nodes.push(node);
       }
 
-      this.remove();
+      this.dangerouslyRemove();
     }
   }
 };

src/babel/transformation/transformer-pass.js

@@ -1,5 +1,6 @@
-import includes from "lodash/collection/includes";
+import type Transformer from "./transformer";
 import traverse from "../traversal";
+import type File from "./file";
 
 /**
  * This class is responsible for traversing over the provided `File`s
@@ -11,8 +12,13 @@ export default class TransformerPass {
     this.transformer = transformer;
     this.handlers    = transformer.handlers;
     this.file        = file;
-    this.ran         = false;
     this.key         = transformer.key;
+
+    if (this.canTransform() && transformer.metadata.experimental && !file.opts.experimental) {
+      file.log.warn(`THE TRANSFORMER ${this.key} HAS BEEN MARKED AS EXPERIMENTAL AND IS WIP. USE AT YOUR OWN RISK. ` +
+                    "THIS WILL HIGHLY LIKELY BREAK YOUR CODE SO USE WITH **EXTREME** CAUTION. ENABLE THE " +
+                    "`experimental` OPTION TO IGNORE THIS WARNING.");
+    }
   }
 
   canTransform(): boolean {
@@ -22,13 +28,8 @@ export default class TransformerPass {
 
   transform() {
     var file = this.file;
-
     file.log.debug(`Start transformer ${this.key}`);
-
     traverse(file.ast, this.handlers, file.scope, file);
-
     file.log.debug(`Finish transformer ${this.key}`);
-
-    this.ran = true;
   }
 }

src/babel/transformation/transformer-pipeline.js

@@ -57,10 +57,21 @@ export default class TransformerPipeline {
     return true;
   }
 
+  pretransform(code: string, opts?: Object) {
+    var file = new File(opts, this);
+    return file.wrap(code, function () {
+      file.addCode(code);
+      file.parseCode(code);
+      return file;
+    });
+  }
+
   transform(code: string, opts?: Object) {
     var file = new File(opts, this);
     return file.wrap(code, function () {
-      file.addCode(code, true);
+      file.addCode(code);
+      file.parseCode(code);
+      return file.transform();
     });
   }
 
@@ -71,6 +82,7 @@ export default class TransformerPipeline {
     return file.wrap(code, function () {
       file.addCode(code);
       file.addAst(ast);
+      return file.transform();
     });
   }
 

src/babel/transformation/transformer.js

@@ -4,7 +4,6 @@ import isFunction from "lodash/lang/isFunction";
 import traverse from "../traversal";
 import isObject from "lodash/lang/isObject";
 import assign from "lodash/object/assign";
-import * as acorn from "../../acorn";
 import File from "./file";
 import each from "lodash/collection/each";
 

src/babel/transformation/transformers/aliases.json

@@ -1,5 +1,6 @@
 {
   "useStrict": "strict",
   "es5.runtime": "runtime",
-  "es6.runtime": "runtime"
+  "es6.runtime": "runtime",
+  "minification.inlineExpressions": "minification.constantFolding"
 }

src/babel/transformation/transformers/deprecated.json

@@ -5,7 +5,7 @@
   "es6.symbols": "es6.spec.symbols",
   "es6.blockScopingTDZ": "es6.spec.blockScoping",
 
-  "utility.inlineExpressions": "minification.inlineExpressions",
+  "utility.inlineExpressions": "minification.constantFolding",
   "utility.deadCodeElimination": "minification.deadCodeElimination",
   "utility.removeConsoleCalls": "minification.removeConsole",
   "utility.removeDebugger": "minification.removeDebugger"

src/babel/transformation/transformers/es5/properties.mutators.js

@@ -2,12 +2,19 @@ import * as defineMap from "../../helpers/define-map";
 import * as t from "../../../types";
 
 export function ObjectExpression(node, parent, scope, file) {
-  var mutatorMap = {};
   var hasAny = false;
+  for (var prop of (node.properties: Array)) {
+    if (prop.kind === "get" || prop.kind === "set") {
+      hasAny = true;
+      break;
+    }
+  }
+  if (!hasAny) return;
+
+  var mutatorMap = {};
 
   node.properties = node.properties.filter(function (prop) {
     if (prop.kind === "get" || prop.kind === "set") {
-      hasAny = true;
       defineMap.push(mutatorMap, prop, prop.kind, file);
       return false;
     } else {
@@ -15,8 +22,6 @@ export function ObjectExpression(node, parent, scope, file) {
     }
   });
 
-  if (!hasAny) return;
-
   return t.callExpression(
     t.memberExpression(t.identifier("Object"), t.identifier("defineProperties")),
     [node, defineMap.toDefineObject(mutatorMap)]

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

@@ -1,3 +1,6 @@
+import type NodePath from "../../../traversal/path";
+import type Scope from "../../../traversal/scope";
+import type File from "../../file";
 import traverse from "../../../traversal";
 import object from "../../../helpers/object";
 import * as util from  "../../../util";
@@ -258,7 +261,7 @@ class BlockScoping {
    * Description
    */
 
-  constructor(loopPath?: TraversalPath, blockPath: TraversalPath, parent: Object, scope: Scope, file: File) {
+  constructor(loopPath?: NodePath, blockPath: NodePath, parent: Object, scope: Scope, file: File) {
     this.parent = parent;
     this.scope  = scope;
     this.file   = file;
@@ -597,7 +600,6 @@ class BlockScoping {
       t.variableDeclarator(ret, call)
     ]));
 
-    var loop = this.loop;
     var retCheck;
     var has = this.has;
     var cases = [];

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

@@ -1,12 +1,11 @@
+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 traverse from "../../../traversal";
-import each from "lodash/collection/each";
-import has from "lodash/object/has";
 import * as t from "../../../types";
 
 const PROPERTY_COLLISION_METHOD_NAME = "__initializeProperties";
@@ -35,22 +34,6 @@ var collectPropertyReferencesVisitor = {
   }
 };
 
-var constructorVisitor = {
-  ThisExpression: {
-    enter(node, parent, scope, ref) {
-      return ref;
-    }
-  },
-
-  Function: {
-    enter(node) {
-      if (!node.shadow) {
-        this.skip();
-      }
-    }
-  }
-};
-
 var verifyConstructorVisitor = {
   MethodDefinition: {
     enter() {
@@ -104,7 +87,7 @@ class ClassTransformer {
    * Description
    */
 
-  constructor(path: TraversalPath, file: File) {
+  constructor(path: NodePath, file: File) {
     this.parent = path.parent;
     this.scope  = path.scope;
     this.node   = path.node;
@@ -141,8 +124,6 @@ class ClassTransformer {
 
   run() {
     var superName = this.superName;
-    var className = this.className;
-    var classBody = this.node.body.body;
     var classRef  = this.classRef;
     var file      = this.file;
 
@@ -262,7 +243,7 @@ class ClassTransformer {
     var map = defineMap.push(mutatorMap, node, kind, this.file);
 
     if (enumerable) {
-      map.enumerable = t.literal(true)
+      map.enumerable = t.literal(true);
     }
 
     if (map.decorators) {
@@ -276,9 +257,6 @@ class ClassTransformer {
 
   buildBody() {
     var constructorBody = this.constructorBody;
-    var constructor     = this.constructor;
-    var className       = this.className;
-    var superName       = this.superName;
     var classBody       = this.node.body.body;
     var body            = this.body;
 
@@ -315,7 +293,7 @@ class ClassTransformer {
           this.pushMethod(node, path);
         }
       } else if (t.isClassProperty(node)) {
-        this.pushProperty(node);
+        this.pushProperty(node, path);
       }
     }
 
@@ -375,7 +353,7 @@ class ClassTransformer {
       }
 
       var lastNonNullIndex = 0;
-      for (var i = 0; i < args.length; i++) {
+      for (let i = 0; i < args.length; i++) {
         if (args[i] !== nullNode) lastNonNullIndex = i;
       }
       args = args.slice(0, lastNonNullIndex + 1);
@@ -450,7 +428,7 @@ class ClassTransformer {
    * Description
    */
 
-   verifyConstructor(path: TraversalPath) {
+   verifyConstructor(path: NodePath) {
     var state = {
       hasBareSuper: false,
       bareSuper:    null,
@@ -471,7 +449,7 @@ class ClassTransformer {
    * Push a method to its respective mutatorMap.
    */
 
-  pushMethod(node: { type: "MethodDefinition" }, path?: TraversalPath, allowedIllegal?) {
+  pushMethod(node: { type: "MethodDefinition" }, path?: NodePath, allowedIllegal?) {
     if (!allowedIllegal && t.isLiteral(t.toComputedKey(node), { value: PROPERTY_COLLISION_METHOD_NAME })) {
       throw this.file.errorWithNode(node, messages.get("illegalMethodName", PROPERTY_COLLISION_METHOD_NAME));
     }
@@ -500,10 +478,8 @@ class ClassTransformer {
    * Description
    */
 
-  pushProperty(node: { type: "ClassProperty" }) {
-    var key;
-
-    this.scope.traverse(node, collectPropertyReferencesVisitor, {
+  pushProperty(node: { type: "ClassProperty" }, path: NodePath) {
+    path.traverse(collectPropertyReferencesVisitor, {
       references: this.instancePropRefs,
       scope:      this.scope
     });
@@ -519,7 +495,6 @@ class ClassTransformer {
       this.pushToMap(node, true, "initializer");
 
       var initializers;
-      var body;
       var target;
       if (node.static) {
         initializers = this.staticInitializersId = this.staticInitializersId || this.scope.generateUidIdentifier("staticInitializers");
@@ -558,7 +533,7 @@ class ClassTransformer {
    * Replace the constructor body of our class.
    */
 
-  pushConstructor(method: { type: "MethodDefinition" }, path: TraversalPath) {
+  pushConstructor(method: { type: "MethodDefinition" }, path: NodePath) {
     // https://github.com/babel/babel/issues/1077
     var fnPath = path.get("value");
     if (fnPath.scope.hasOwnBinding(this.classRef.name)) {

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

@@ -1,13 +1,12 @@
 import * as messages from "../../../messages";
-import * as t from "../../../types";
 
-export function AssignmentExpression(node, parent, scope, file) {
-  var ids = this.getBindingIdentifiers();
+function checkPath(path, file) {
+  var ids = path.getBindingIdentifiers();
 
   for (var name in ids) {
     var id = ids[name];
 
-    var binding = scope.getBinding(name);
+    var binding = path.scope.getBinding(name);
 
     // no binding exists
     if (!binding) continue;
@@ -24,8 +23,19 @@ export function AssignmentExpression(node, parent, scope, file) {
   }
 }
 
+export function AssignmentExpression(node, parent, scope, file) {
+  checkPath(this, file);
+}
+
 export { AssignmentExpression as UpdateExpression };
 
 export function VariableDeclaration(node) {
   if (node.kind === "const") node.kind = "let";
 }
+
+export function ForXStatement(node, parent, scope, file) {
+  var left = this.get("left");
+  if (left.isIdentifier() || left.isPattern()) {
+    checkPath(left, file);
+  }
+}

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

@@ -107,30 +107,10 @@ export function CatchClause(node, parent, scope, file) {
   node.body.body = nodes.concat(node.body.body);
 }
 
-export function ExpressionStatement(node, parent, scope, file) {
-  var expr = node.expression;
-  if (expr.type !== "AssignmentExpression") return;
-  if (!t.isPattern(expr.left)) return;
-  if (this.isCompletionRecord()) return;
-
-  var destructuring = new DestructuringTransformer({
-    operator: expr.operator,
-    scope:    scope,
-    file:     file,
-  });
-
-  return destructuring.init(expr.left, expr.right);
-}
-
 export function AssignmentExpression(node, parent, scope, file) {
   if (!t.isPattern(node.left)) return;
 
-  var ref = scope.generateUidIdentifier("temp");
-
   var nodes = [];
-  nodes.push(t.variableDeclaration("var", [
-    t.variableDeclarator(ref, node.right)
-  ]));
 
   var destructuring = new DestructuringTransformer({
     operator: node.operator,
@@ -139,13 +119,24 @@ export function AssignmentExpression(node, parent, scope, file) {
     nodes: nodes
   });
 
-  if (t.isArrayExpression(node.right)) {
-    destructuring.arrays[ref.name] = true;
+  var ref;
+  if (this.isCompletionRecord() || !this.parentPath.isExpressionStatement()) {
+    ref = scope.generateUidIdentifierBasedOnNode(node.right, "ref");
+
+    nodes.push(t.variableDeclaration("var", [
+      t.variableDeclarator(ref, node.right)
+    ]));
+
+    if (t.isArrayExpression(node.right)) {
+      destructuring.arrays[ref.name] = true;
+    }
   }
 
-  destructuring.init(node.left, ref);
+  destructuring.init(node.left, ref || node.right);
 
-  nodes.push(t.expressionStatement(ref));
+  if (ref) {
+    nodes.push(t.expressionStatement(ref));
+  }
 
   return nodes;
 }
@@ -160,7 +151,7 @@ function variableDeclarationHasPattern(node) {
 }
 
 export function VariableDeclaration(node, parent, scope, file) {
-  if (t.isForInStatement(parent) || t.isForOfStatement(parent)) return;
+  if (t.isForXStatement(parent)) return;
   if (!variableDeclarationHasPattern(node)) return;
 
   var nodes = [];
@@ -498,7 +489,6 @@ class DestructuringTransformer {
     // trying to destructure a value that we can't evaluate more than once so we
     // need to save it to a variable
 
-    var shouldMemoise = true;
     if (!t.isArrayExpression(ref) && !t.isMemberExpression(ref)) {
       var memo = this.scope.maybeGenerateMemoised(ref, true);
       if (memo) {

src/babel/transformation/transformers/es6/for-of.js

@@ -31,7 +31,7 @@ export function ForOfStatement(node, parent, scope, file) {
 
   if (build.replaceParent) {
     this.parentPath.replaceWithMultiple(build.node);
-    this.remove();
+    this.dangerouslyRemove();
   } else {
     return build.node;
   }

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

@@ -19,8 +19,8 @@ export function ImportDeclaration(node, parent, scope, file) {
   var nodes = [];
 
   if (node.specifiers.length) {
-    for (var i = 0; i < node.specifiers.length; i++) {
-      file.moduleFormatter.importSpecifier(node.specifiers[i], node, nodes, parent);
+    for (var specifier of (node.specifiers: Array)) {
+      file.moduleFormatter.importSpecifier(specifier, node, nodes, parent);
     }
   } else {
     file.moduleFormatter.importDeclaration(node, nodes, parent);

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

@@ -1,6 +1,5 @@
 import callDelegate from "../../helpers/call-delegate";
 import * as util from  "../../../util";
-import traverse from  "../../../traversal";
 import * as t from "../../../types";
 
 var hasDefaults = function (node) {

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

@@ -9,6 +9,13 @@ var memberExpressionOptimisationVisitor = {
       return this.skip();
     }
 
+    var stop = () => {
+      state.canOptimise = false;
+      this.stop();
+    };
+
+    if (this.isArrowFunctionExpression()) return stop();
+
     // skip over functions as whatever `arguments` we reference inside will refer
     // to the wrong function
     if (this.isFunctionDeclaration() || this.isFunctionExpression()) {
@@ -31,8 +38,7 @@ var memberExpressionOptimisationVisitor = {
       }
     }
 
-    state.canOptimise = false;
-    this.stop();
+    stop();
   }
 };
 
@@ -90,8 +96,7 @@ export function Func/*tion*/(node, parent, scope, file) {
 
   // we only have shorthands and there's no other references
   if (state.canOptimise && state.candidates.length) {
-    for (var i = 0; i < state.candidates.length; i++) {
-      var candidate = state.candidates[i];
+    for (var candidate of (state.candidates: Array)) {
       candidate.replaceWith(argsId);
       optimizeMemberExpression(candidate.parent, node.params.length);
     }

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

@@ -1,29 +1,59 @@
-import traverse from "../../../traversal";
 import * as t from "../../../types";
 
+function buildAssert(node, file) {
+  return t.callExpression(
+    file.addHelper("temporal-assert-defined"),
+    [node, t.literal(node.name), file.addHelper("temporal-undefined")]
+  );
+}
+
+function references(node, scope, state) {
+  var declared = state.letRefs[node.name];
+  if (!declared) return false;
+
+  // declared node is different in this scope
+  return scope.getBindingIdentifier(node.name) === declared;
+}
+
 var visitor = {
   ReferencedIdentifier(node, parent, scope, state) {
     if (t.isFor(parent) && parent.left === node) return;
 
-    var declared = state.letRefs[node.name];
-    if (!declared) return;
+    if (!references(node, scope, state)) return;
 
-    // declared node is different in this scope
-    if (scope.getBindingIdentifier(node.name) !== declared) return;
-
-    var assert = t.callExpression(
-      state.file.addHelper("temporal-assert-defined"),
-      [node, t.literal(node.name), state.file.addHelper("temporal-undefined")]
-    );
+    var assert = buildAssert(node, state.file);
 
     this.skip();
 
-    if (t.isAssignmentExpression(parent) || t.isUpdateExpression(parent)) {
+    if (t.isUpdateExpression(parent)) {
       if (parent._ignoreBlockScopingTDZ) return;
       this.parentPath.replaceWith(t.sequenceExpression([assert, parent]));
     } else {
       return t.logicalExpression("&&", assert, node);
     }
+  },
+
+  AssignmentExpression: {
+    exit(node, parent, scope, state) {
+      if (node._ignoreBlockScopingTDZ) return;
+
+      var nodes = [];
+      var ids = this.getBindingIdentifiers();
+
+      for (var name in ids) {
+        var id = ids[name];
+
+        if (references(id, scope, state)) {
+          nodes.push(buildAssert(id, state.file));
+        }
+      }
+
+      if (nodes.length) {
+        node._ignoreBlockScopingTDZ = true;
+        nodes.push(node);
+        return nodes.map(t.expressionStatement);
+      }
+    }
   }
 };
 

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

@@ -1,7 +1,8 @@
 import * as t from "../../../types";
 
 export var metadata = {
-  optional: true
+  optional: true,
+  group: "builtin-pre"
 };
 
 export function TemplateLiteral(node, parent, scope, file) {

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

@@ -1,4 +1,3 @@
-import includes from "lodash/collection/includes";
 import * as t from "../../../types";
 
 function getSpreadLiteral(spread, scope) {

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

@@ -1,7 +1,6 @@
 import reduceRight from "lodash/collection/reduceRight";
 import * as messages from "../../../messages";
 import flatten from "lodash/array/flatten";
-import traverse from "../../../traversal";
 import * as util from  "../../../util";
 import map from "lodash/collection/map";
 import * as t from "../../../types";
@@ -21,7 +20,7 @@ function returnBlock(expr) {
 }
 
 var visitor = {
-  enter(node, parent, scope, state) {
+  enter(node, parent) {
     if (t.isTryStatement(parent)) {
       if (node === parent.block) {
         this.skip();
@@ -35,7 +34,7 @@ var visitor = {
     return state.subTransform(node.argument);
   },
 
-  Function(node, parent, scope, state) {
+  Function() {
     this.skip();
   },
 
@@ -51,7 +50,7 @@ var visitor = {
   },
 
   ReferencedIdentifier(node, parent, scope, state) {
-    if (node.name === "arguments" && !state.isShadowed) {
+    if (node.name === "arguments" && (!state.isShadowed || node._shadowedFunctionLiteral)) {
       state.needsArguments = true;
       state.argumentsPaths.push(this);
     }
@@ -128,7 +127,6 @@ class TailCallTransformer {
   }
 
   run() {
-    var scope = this.scope;
     var node  = this.node;
 
     // only tail recursion can be optimized as for now, so we can skip anonymous
@@ -204,13 +202,14 @@ class TailCallTransformer {
     }
 
     if (this.needsArguments || this.setsArguments) {
-      for (var path of (this.argumentsPaths: Array)) {
+      for (let path of (this.argumentsPaths: Array)) {
         path.replaceWith(this.argumentsId);
       }
 
       var decl = t.variableDeclarator(this.argumentsId);
       if (this.argumentsId) {
         decl.init = t.identifier("arguments");
+        decl.init._shadowedFunctionLiteral = true;
       }
       topVars.push(decl);
     }
@@ -291,7 +290,8 @@ class TailCallTransformer {
   }
 
   subTransformCallExpression(node) {
-    var callee = node.callee, thisBinding, args;
+    var callee = node.callee;
+    var thisBinding, args;
 
     if (t.isMemberExpression(callee, { computed: false }) && t.isIdentifier(callee.property)) {
       switch (callee.property.name) {
@@ -301,6 +301,7 @@ class TailCallTransformer {
 
         case "apply":
           args = node.arguments[1] || t.identifier("undefined");
+          this.needsArguments = true;
           break;
 
         default:
@@ -334,6 +335,10 @@ 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();
 
@@ -349,14 +354,14 @@ class TailCallTransformer {
       var elems = args.elements;
       for (let i = 0; i < elems.length && i < params.length; i++) {
         let param = params[i];
-        var elem = elems[i] || (elems[i] = t.identifier("undefined"));
+        let elem = elems[i] || (elems[i] = t.identifier("undefined"));
         if (!param._isDefaultPlaceholder) {
           elems[i] = t.assignmentExpression("=", param, elem);
         }
       }
 
       if (!this.needsArguments) {
-        for (var elem of (elems: Array)) {
+        for (let elem of (elems: Array)) {
           body.push(t.expressionStatement(elem));
         }
       }

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

@@ -1,9 +1,26 @@
+/* eslint no-unused-vars: 0 */
+
 import * as t from "../../../types";
 
-var buildBinaryExpression = function (left, right) {
-  return t.binaryExpression("+", left, right);
+export var metadata = {
+  group: "builtin-pre"
 };
 
+function buildBinaryExpression(left, right) {
+  var node = t.binaryExpression("+", left, right);
+  node._templateLiteralProduced = true;
+  return node;
+}
+
+function crawl(path) {
+  if (path.is("_templateLiteralProduced")) {
+    crawl(path.get("left"));
+    crawl(path.get("right"));
+  } else if (!path.isTypeAnnotationGeneric("String") && !path.isTypeAnnotationGeneric("Number")) {
+    path.replaceWith(t.callExpression(t.identifier("String"), [path.node]));
+  }
+}
+
 export function TaggedTemplateExpression(node, parent, scope, file) {
   var quasi = node.quasi;
   var args  = [];
@@ -11,8 +28,7 @@ export function TaggedTemplateExpression(node, parent, scope, file) {
   var strings = [];
   var raw     = [];
 
-  for (var i = 0; i < quasi.quasis.length; i++) {
-    var elem = quasi.quasis[i];
+  for (var elem of (quasi.quasis: Array)) {
     strings.push(t.literal(elem.value.cooked));
     raw.push(t.literal(elem.value.raw));
   }
@@ -31,11 +47,8 @@ export function TaggedTemplateExpression(node, parent, scope, file) {
 
 export function TemplateLiteral(node, parent, scope, file) {
   var nodes = [];
-  var i;
-
-  for (i = 0; i < node.quasis.length; i++) {
-    var elem = node.quasis[i];
 
+  for (let elem of (node.quasis: Array)) {
     nodes.push(t.literal(elem.value.cooked));
 
     var expr = node.expressions.shift();
@@ -49,11 +62,12 @@ export function TemplateLiteral(node, parent, scope, file) {
 
     var root = buildBinaryExpression(nodes.shift(), nodes.shift());
 
-    for (i = 0; i < nodes.length; i++) {
-      root = buildBinaryExpression(root, nodes[i]);
+    for (let node of (nodes: Array)) {
+      root = buildBinaryExpression(root, node);
     }
 
-    return root;
+    this.replaceWith(root);
+    //crawl(this);
   } else {
     return nodes[0];
   }

src/babel/transformation/transformers/es7/comprehensions.js

@@ -10,7 +10,7 @@ export var metadata = {
 export function ComprehensionExpression(node, parent, scope, file) {
   var callback = array;
   if (node.generator) callback = generator;
-  return callback(node, parent, scope, file);
+  return callback(node, parent, scope);
 }
 
 function generator(node) {
@@ -25,7 +25,7 @@ function generator(node) {
   return t.callExpression(container, []);
 }
 
-function array(node, parent, scope, file) {
+function array(node, parent, scope) {
   var uid = scope.generateUidIdentifierBasedOnNode(parent);
 
   var container = util.template("array-comprehension-container", {

src/babel/transformation/transformers/es7/decorators.js

@@ -10,8 +10,8 @@ export var metadata = {
 
 export function ObjectExpression(node, parent, scope, file) {
   var hasDecorators = false;
-  for (var i = 0; i < node.properties.length; i++) {
-    var prop = node.properties[i];
+  for (let i = 0; i < node.properties.length; i++) {
+    let prop = node.properties[i];
     if (prop.decorators) {
       hasDecorators = true;
       break;
@@ -21,12 +21,12 @@ export function ObjectExpression(node, parent, scope, file) {
 
   var mutatorMap = {};
 
-  for (var i = 0; i < node.properties.length; i++) {
-    var prop = node.properties[i];
+  for (let i = 0; i < node.properties.length; i++) {
+    let prop = node.properties[i];
     if (prop.decorators) memoiseDecorators(prop.decorators, scope);
 
 
-    if (prop.kind === "init") {
+    if (prop.kind === "init" && !prop.method) {
       prop.kind = "";
       prop.value = t.functionExpression(null, [], t.blockStatement([
         t.returnStatement(prop.value)

src/babel/transformation/transformers/index.js

@@ -1,16 +1,21 @@
 export default {
-  //- builtin-setup
+  //- builtin-prepass
+  "minification.constantFolding":          require("./minification/constant-folding"),
+
+  //- builtin-pre
   strict:                                  require("./other/strict"),
+  eval:                                    require("./other/eval"),
   _explode:                                require("./internal/explode"),
   _validation:                             require("./internal/validation"),
   _hoistDirectives:                        require("./internal/hoist-directives"),
   "minification.removeDebugger":           require("./minification/remove-debugger"),
   "minification.removeConsole":            require("./minification/remove-console"),
   "utility.inlineEnvironmentVariables":    require("./utility/inline-environment-variables"),
-  "minification.inlineExpressions":        require("./minification/inline-expressions"),
   "minification.deadCodeElimination":      require("./minification/dead-code-elimination"),
   _modules:                                require("./internal/modules"),
   "spec.functionName":                     require("./spec/function-name"),
+  "es6.spec.templateLiterals":             require("./es6/spec.template-literals"),
+  "es6.templateLiterals":                  require("./es6/template-literals"),
 
   //- builtin-basic
   // this is where the bulk of the ES6 transformations take place, none of them require traversal state
@@ -32,8 +37,6 @@ export default {
   "es6.objectSuper":                       require("./es6/object-super"),
   "es7.objectRestSpread":                  require("./es7/object-rest-spread"),
   "es7.exponentiationOperator":            require("./es7/exponentiation-operator"),
-  "es6.spec.templateLiterals":             require("./es6/spec.template-literals"),
-  "es6.templateLiterals":                  require("./es6/template-literals"),
   "es5.properties.mutators":               require("./es5/properties.mutators"),
   "es6.properties.shorthand":              require("./es6/properties.shorthand"),
   "es6.properties.computed":               require("./es6/properties.computed"),
@@ -51,8 +54,6 @@ export default {
   "es6.spec.symbols":                      require("./es6/spec.symbols"),
   "es7.functionBind":                      require("./es7/function-bind"),
   "spec.undefinedToVoid":                  require("./spec/undefined-to-void"),
-  jscript:                                 require("./other/jscript"),
-  flow:                                    require("./other/flow"),
 
   //- builtin-advanced
   "es6.destructuring":                     require("./es6/destructuring"),
@@ -60,13 +61,11 @@ export default {
   "es6.spec.blockScoping":                 require("./es6/spec.block-scoping"),
   reactCompat:                             require("./other/react-compat"),
   react:                                   require("./other/react"),
+  regenerator:                             require("./other/regenerator"),
 
   // es6 syntax transformation is **forbidden** past this point since regenerator will chuck a massive
   // hissy fit
 
-  //- regenerator
-  regenerator:                             require("./other/regenerator"),
-
   //- builtin-modules
   runtime:                                 require("./other/runtime"),
   "es6.modules":                           require("./es6/modules"),
@@ -83,4 +82,6 @@ export default {
   "minification.memberExpressionLiterals": require("./minification/member-expression-literals"),
   "minification.propertyLiterals":         require("./minification/property-literals"),
   _blockHoist:                             require("./internal/block-hoist"),
+  jscript:                                 require("./other/jscript"),
+  flow:                                    require("./other/flow"),
 };

src/babel/transformation/transformers/internal/explode.js

@@ -2,7 +2,7 @@ import clone from "lodash/lang/clone";
 import * as t from "../../../types";
 
 export var metadata = {
-  group: "builtin-setup"
+  group: "builtin-pre"
 };
 
 function buildClone(bindingKey, refKey, check?) {

src/babel/transformation/transformers/internal/hoist-directives.js

@@ -1,7 +1,7 @@
 import * as t from "../../../types";
 
 export var metadata = {
-  group: "builtin-setup"
+  group: "builtin-pre"
 };
 
 export var BlockStatement = {

src/babel/transformation/transformers/internal/module-formatter.js

@@ -1,19 +1,15 @@
-import * as strict from "../../helpers/strict";
-
 export var metadata = {
   group: "builtin-modules"
 };
 
 export var Program = {
   exit(program, parent, scope, file) {
-    strict.wrap(program, function () {
-      // ensure that these are at the top, just like normal imports
-      for (var node of (file.dynamicImports: Array)) {
-        node._blockHoist = 3;
-      }
+    // ensure that these are at the top, just like normal imports
+    for (var node of (file.dynamicImports: Array)) {
+      node._blockHoist = 3;
+    }
 
-      program.body = file.dynamicImports.concat(program.body);
-    });
+    program.body = file.dynamicImports.concat(program.body);
 
     if (!file.transformers["es6.modules"].canTransform()) return;
 

src/babel/transformation/transformers/internal/modules.js

@@ -7,45 +7,43 @@
 import clone from "lodash/lang/clone";
 import * as t from "../../../types";
 
-export var metadata = {
-  group: "builtin-setup"
-};
-
-export function ImportDeclaration(node, parent, scope, file) {
-  if (node.source) {
-    node.source.value = file.resolveModuleSource(node.source.value);
-  }
+function getDeclar(node) {
+  var declar = node.declaration;
+  t.inheritsComments(declar, node);
+  t.removeComments(node);
+  declar._ignoreUserWhitespace = true;
+  return declar;
 }
 
-export { ImportDeclaration as ExportAllDeclaration };
+export var metadata = {
+  group: "builtin-pre"
+};
 
 export function ExportDefaultDeclaration(node, parent, scope) {
-  ImportDeclaration.apply(this, arguments);
-
   var declar = node.declaration;
 
-  var getDeclar = function () {
-    declar._ignoreUserWhitespace = true;
-    return declar;
-  };
-
   if (t.isClassDeclaration(declar)) {
     // export default class Foo {};
+    let nodes = [getDeclar(node), node];
     node.declaration = declar.id;
-    return [getDeclar(), node];
+    return nodes;
   } else if (t.isClassExpression(declar)) {
     // export default class {};
     var temp = scope.generateUidIdentifier("default");
-    declar = t.variableDeclaration("var", [
+    node.declaration = t.variableDeclaration("var", [
       t.variableDeclarator(temp, declar)
     ]);
+
+    let nodes = [getDeclar(node), node];
     node.declaration = temp;
-    return [getDeclar(), node];
+    return nodes;
   } else if (t.isFunctionDeclaration(declar)) {
     // export default function Foo() {}
     node._blockHoist = 2;
+
+    let nodes = [getDeclar(node), node];
     node.declaration = declar.id;
-    return [getDeclar(), node];
+    return nodes;
   }
 }
 
@@ -54,26 +52,23 @@ function buildExportSpecifier(id) {
 }
 
 export function ExportNamedDeclaration(node, parent, scope) {
-  ImportDeclaration.apply(this, arguments);
-
   var declar = node.declaration;
 
-  var getDeclar = function () {
-    declar._ignoreUserWhitespace = true;
-    return declar;
-  };
-
   if (t.isClassDeclaration(declar)) {
     // export class Foo {}
     node.specifiers  = [buildExportSpecifier(declar.id)];
+
+    let nodes = [getDeclar(node), node];
     node.declaration = null;
-    return [getDeclar(), node];
+    return nodes;
   } else if (t.isFunctionDeclaration(declar)) {
     // export function Foo() {}
     node.specifiers  = [buildExportSpecifier(declar.id)];
-    node.declaration = null;
     node._blockHoist = 2;
-    return [getDeclar(), node];
+
+    let nodes = [getDeclar(node), node];
+    node.declaration = null;
+    return nodes;
   } else if (t.isVariableDeclaration(declar)) {
     // export var foo = "bar";
     var specifiers = [];

src/babel/transformation/transformers/internal/validation.js

@@ -2,7 +2,7 @@ import * as messages from "../../../messages";
 import * as t from "../../../types";
 
 export var metadata = {
-  group: "builtin-setup"
+  group: "builtin-pre"
 };
 
 export function ForOfStatement(node, parent, scope, file) {

src/babel/transformation/transformers/minification/constant-folding.js

@@ -0,0 +1,49 @@
+import * as t from "../../../types";
+
+export var metadata = {
+  optional: true,
+  group: "builtin-prepass",
+  experimental: true
+};
+
+export function AssignmentExpression() {
+  var left = this.get("left");
+  if (!left.isIdentifier()) return;
+
+  var binding = this.scope.getBinding(left.node.name);
+  if (!binding || binding.deoptValue) return;
+
+  var evaluated = this.get("right").evaluate();
+  if (evaluated.confident) {
+    binding.setValue(evaluated.value);
+  } else {
+    binding.deoptValue();
+  }
+}
+
+export function IfStatement() {
+  var evaluated = this.get("test").evaluate();
+  if (!evaluated.confident) return this.skip();
+
+  if (evaluated.value) {
+    this.skipKey("alternate");
+  } else {
+    this.skipKey("consequent");
+  }
+}
+
+export var Scopable = {
+  exit() {
+    for (var name in this.scope.bindings) {
+      var binding = this.scope.bindings[name];
+      binding.clearValue();
+    }
+  }
+};
+
+export var Expression = {
+  exit() {
+    var res = this.evaluate();
+    if (res.confident) return t.valueToNode(res.value);
+  }
+};

src/babel/transformation/transformers/minification/dead-code-elimination.js

@@ -19,7 +19,8 @@ function toStatements(node) {
 
 export var metadata = {
   optional: true,
-  group: "builtin-setup"
+  group: "builtin-pre",
+  experimental: true
 };
 
 export function ReferencedIdentifier(node, parent, scope) {
@@ -33,27 +34,37 @@ export function ReferencedIdentifier(node, parent, scope) {
   }
   if (!replacement) return;
 
-  if (this.findParent((node) => replacement)) {
+  // ensure it's a "pure" type
+  if (!scope.isPure(replacement, true)) return;
+
+  if (t.isClass(replacement) || t.isFunction(replacement)) {
+    // don't change this if it's in a different scope, this can be bad
+    // for performance since it may be inside a loop or deeply nested in
+    // hot code
+    if (binding.path.scope.parent !== scope) return;
+  }
+
+  if (this.findParent((node) => node === replacement)) {
     return;
   }
 
   t.toExpression(replacement);
   scope.removeBinding(node.name);
-  binding.path.remove();
+  binding.path.dangerouslyRemove();
   return replacement;
 }
 
 export function FunctionDeclaration(node, parent, scope) {
   var bindingInfo = scope.getBinding(node.id.name);
   if (bindingInfo && !bindingInfo.referenced) {
-    this.remove();
+    this.dangerouslyRemove();
   }
 }
 
 export { FunctionDeclaration as ClassDeclaration };
 
 export function VariableDeclarator(node, parent, scope) {
-  if (!t.isIdentifier(node.id) || !scope.isPure(node.init)) return;
+  if (!t.isIdentifier(node.id) || !scope.isPure(node.init, true)) return;
   FunctionDeclaration.apply(this, arguments);
 }
 
@@ -66,8 +77,27 @@ export function ConditionalExpression(node, parent, scope) {
   }
 }
 
+export function BlockStatement(node) {
+  var paths = this.get("body");
+
+  var purge = false;
+
+  for (var i = 0; i < paths.length; i++) {
+    let path = paths[i];
+
+    if (!purge && path.isCompletionStatement()) {
+      purge = true;
+      continue;
+    }
+
+    if (purge && !path.isFunctionDeclaration()) {
+      path.dangerouslyRemove();
+    }
+  }
+}
+
 export var IfStatement = {
-  exit(node, parent, scope) {
+  exit(node) {
     var consequent = node.consequent;
     var alternate  = node.alternate;
     var test = node.test;
@@ -96,7 +126,7 @@ export var IfStatement = {
       if (alternate) {
         return toStatements(alternate);
       } else {
-        return this.remove();
+        return this.dangerouslyRemove();
       }
     }
 

src/babel/transformation/transformers/minification/inline-expressions.js

@@ -1,17 +0,0 @@
-import * as t from "../../../types";
-
-export var metadata = {
-  optional: true,
-  group: "builtin-setup"
-};
-
-export var Expression = {
-  exit(node, parent, scope) {
-    var res = this.evaluate();
-    if (res.confident) return t.valueToNode(res.value);
-  }
-};
-
-export function Identifier() {
-  // override Expression
-}

src/babel/transformation/transformers/minification/remove-console.js

@@ -2,15 +2,15 @@ import * as t from "../../../types";
 
 export var metadata = {
   optional: true,
-  group: "builtin-setup"
+  group: "builtin-pre"
 };
 
 export function CallExpression(node, parent) {
   if (this.get("callee").matchesPattern("console", true)) {
     if (t.isExpressionStatement(parent)) {
-      this.parentPath.remove();
+      this.parentPath.dangerouslyRemove();
     } else {
-      this.remove();
+      this.dangerouslyRemove();
     }
   }
 }

src/babel/transformation/transformers/minification/remove-debugger.js

@@ -1,12 +1,8 @@
-import * as t from "../../../types";
-
 export var metadata = {
   optional: true,
-  group: "builtin-setup"
+  group: "builtin-pre"
 };
 
-export function ExpressionStatement(node) {
-  if (this.get("expression").isIdentifier({ name: "debugger" })) {
-    this.remove();
-  }
+export function DebuggerStatement(node) {
+  this.dangerouslyRemove();
 }

src/babel/transformation/transformers/optimisation/flow.for-of.js

@@ -1,12 +1,11 @@
 import { _ForOfStatementArray } from "../es6/for-of";
-import * as t from "../../../types";
 
 export var metadata = {
   optional: true
 };
 
 export function ForOfStatement(node, parent, scope, file) {
-  if (this.get("right").isTypeGeneric("Array")) {
+  if (this.get("right").isTypeAnnotationGeneric("Array")) {
     return _ForOfStatementArray.call(this, node, scope, file);
   }
 }

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

@@ -1,5 +1,3 @@
-import * as react from "../../helpers/react";
-
 export var metadata = {
   optional: true
 };

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

@@ -0,0 +1,21 @@
+import traverse from "../../../traversal";
+import parse from "../../../helpers/parse";
+
+export var metadata = {
+  group: "builtin-pre",
+  optional: true
+};
+
+export function CallExpression(node) {
+  if (this.get("callee").isIdentifier({ name: "eval" }) && node.arguments.length === 1) {
+    var evaluate = this.get("arguments")[0].evaluate();
+    if (!evaluate.confident) return;
+
+    var code = evaluate.value;
+    if (typeof code !== "string") return;
+
+    var ast = parse(code);
+    traverse.removeProperties(ast);
+    return ast.program;
+  }
+}

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

@@ -1,11 +1,14 @@
-import * as t from "../../../types";
+export var metadata = {
+  group: "builtin-trailing"
+};
 
 export function Flow(node) {
-  this.remove();
+  this.dangerouslyRemove();
 }
 
 export function ClassProperty(node) {
   node.typeAnnotation = null;
+  if (!node.value) this.dangerouslyRemove();
 }
 
 export function Class(node) {
@@ -24,9 +27,9 @@ export function TypeCastExpression(node) {
 }
 
 export function ImportDeclaration(node) {
-  if (node.isType) this.remove();
+  if (node.isType) this.dangerouslyRemove();
 }
 
 export function ExportDeclaration(node) {
-  if (this.get("declaration").isTypeAlias()) this.remove();
+  if (this.get("declaration").isTypeAlias()) this.dangerouslyRemove();
 }

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

@@ -1,18 +1,21 @@
 import * as t from "../../../types";
 
 export var metadata = {
+  group: "builtin-trailing",
   optional: true
 };
 
-export function FunctionExpression(node, print) {
-  if (!node.id) return;
-  node._ignoreUserWhitespace = true;
+export var FunctionExpression = {
+  exit(node) {
+    if (!node.id) return;
+    node._ignoreUserWhitespace = true;
 
-  return t.callExpression(
-    t.functionExpression(null, [], t.blockStatement([
-      t.toStatement(node),
-      t.returnStatement(node.id)
-    ])),
-    []
-  );
-}
+    return t.callExpression(
+      t.functionExpression(null, [], t.blockStatement([
+        t.toStatement(node),
+        t.returnStatement(node.id)
+      ])),
+      []
+    );
+  }
+};

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

@@ -3,27 +3,29 @@ import * as t from "../../../types";
 import { NodePath } from "ast-types";
 
 export var metadata = {
-  group: "regenerator"
+  group: "builtin-advanced"
 };
 
-export function Func/*tion*/(node) {
-  if (node.async || node.generator) {
-    // Although this code transforms only the subtree rooted at the given
-    // Function node, that node might contain other generator functions
-    // that will also be transformed. It might help performance to ignore
-    // nested functions, and rely on the traversal to visit them later,
-    // but that's a small optimization. Starting here instead of at the
-    // root of the AST is the key optimization, since huge async/generator
-    // functions are relatively rare.
-    regenerator.transform(convertTraversalPathToNodePath(this));
+export var Func/*tion*/ = {
+  exit(node) {
+    if (node.async || node.generator) {
+      // Although this code transforms only the subtree rooted at the given
+      // Function node, that node might contain other generator functions
+      // that will also be transformed. It might help performance to ignore
+      // nested functions, and rely on the traversal to visit them later,
+      // but that's a small optimization. Starting here instead of at the
+      // root of the AST is the key optimization, since huge async/generator
+      // functions are relatively rare.
+      regenerator.transform(convertNodePath(this));
+    }
   }
-}
+};
 
-// Given a TraversalPath, return a NodePath that includes full ancestry
-// information (up to and including the Program node). This is complicated
-// by having to include intermediate objects like blockStatement.body
+// Given a Babel NodePath, return an ast-types NodePath that includes full
+// ancestry information (up to and including the Program node). This is
+// complicated by having to include intermediate objects like blockStatement.body
 // arrays, in addition to Node objects.
-function convertTraversalPathToNodePath(path) {
+function convertNodePath(path) {
   var programNode;
   var keysAlongPath = [];
 

src/babel/transformation/transformers/other/runtime/index.js

@@ -1,12 +1,7 @@
-import includes from "lodash/collection/includes";
-import traverse from "../../../../traversal";
-import * as util from  "../../../../util";
 import has from "lodash/object/has";
 import * as t from "../../../../types";
 import definitions from "./definitions";
 
-var isSymbolIterator = t.buildMatchMemberExpression("Symbol.iterator");
-
 const RUNTIME_MODULE_NAME = "babel-runtime";
 
 export var metadata = {

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

@@ -1,14 +1,13 @@
-import * as messages from "../../../messages";
 import * as t from "../../../types";
 
 export var metadata = {
-  group: "builtin-setup"
+  group: "builtin-pre"
 };
 
 const THIS_BREAK_KEYS = ["FunctionExpression", "FunctionDeclaration", "ClassExpression", "ClassDeclaration"];
 
 export var Program = {
-  enter(program, parent, scope, file) {
+  enter(program) {
     var first = program.body[0];
 
     var directive;
@@ -24,7 +23,7 @@ export var Program = {
     }
     directive._blockHoist = Infinity;
   }
-}
+};
 
 export function ThisExpression() {
   if (!this.findParent((node) => !node.shadow && THIS_BREAK_KEYS.indexOf(node.type) >= 0)) {