v5.0.2

.gitignore

@@ -11,8 +11,6 @@ test/core/tmp
 coverage
 dist
 .package.json
-packages/babel-runtime/es5/helpers/*.js
-packages/babel-runtime/es5/regenerator/*.js
-packages/babel-runtime/es3/helpers/*.js
-packages/babel-runtime/es3/regenerator/*.js
+packages/babel-runtime/helpers/*.js
+packages/babel-runtime/regenerator/*.js
 lib

CHANGELOG.md

@@ -13,15 +13,55 @@ _Note: Gaps between patch versions are faulty/broken releases._
 
 See [CHANGELOG - 6to5](CHANGELOG-6to5.md) for the pre-4.0.0 version changelog.
 
+## 5.0.1
+
+ * **Bug Fix**
+  * Fix duplicate declaration regression.
+  * Fix not being able to call non-writable methods.
+
 ## 5.0.0
 
  * **New Feature**
   * Decorators based on [@wycat's](https://github.com/wycats) [stage 1 proposal](https://github.com/wycats/javascript-decorators).
   * Class property initializers based on [@jeffmo's](https://github.com/jeffmo) [stage 0 proposal](https://gist.github.com/jeffmo/054df782c05639da2adb).
+  * Export extensions based on [@leebyron's](https://github.com/leebyron) [stage 1 proposal](https://github.com/leebyron/ecmascript-more-export-from).
+  * UMD module formatter now supports globals.
+  * Add `es3.runtime`, `optimisation.react.inlineElements` and `optimisation.react.constantElements` transformers.
+  * Add stage option that replaces the experimental one.
+  * Allow ES7 transformer to be enabled via `optional` instead of only via `stage`.
+  * Infer string quotes to use in the code generator.
+  * Consider `export { foo as default  };` to be the same as `export default foo;`.
+  * Add `nonStandard` option that can be set to `false` to remove parser support for JSX and Flow.
+  * Add `jsxPragma` option.
+  * Automatically generate CLI options based on internal API options.
+  * Add support for `.babelrc` on absolute paths.
+  * Plugin API!
  * **Internal**
+  * Export `options` in browser API.
+  * Rewritten parser.
+  * Don't block hoist when runtime transformer is enabled in system module formatter.
+  * Rewritten the internal traversal and node replacement API to use "paths" that abstracts out node relationships.
+ * **Polish**
+  * JSX output is now more inline with the official JSX transformer.
+  * Hoist block scoping IIFE - this improves memory usage and performance.
+  * Better IIFE detection - references are now checked to see if they're referencing the binding we're searching for.
+  * Check for import reassignments in constants transformer.
+  * Make method definitions with expression bodies illegal.
+  * Save register cache on tick instead of `SIGINT`.
+  * Enable strict mode on babel-node eval flag.
+ * **Bug Fixes**
+  * Add support for live bindings. This change also increases the reliablity of export specifier renaming.
+  * Add support for super update and non equals assignment expressions.
+  * Rename shadow constructor binding in classes.
+  * Seed next iteration bindings with previous fresh bindings when reassinging loop block scoped variables.
+  * Fix new expression spread referencing the wrong constructor.
+  * Call `resolveModuleSource` on dynamic imports.
+  * Added `param` to list of duplicate declaration kinds.
  * **Breaking Changes**
   * The Babel playground has been removed.
   * ES7 Abstract References have been removed.
+  * Experimental option has been removed in favor of a stage option.
+  * Rename `returnUsedHelpers` to `metadataUsedHelpers`.
 
 ## 4.7.16
 

CONTRIBUTING.md

@@ -20,7 +20,7 @@ Then you need to run:
 $ make watch-core
 ```
 
-This will compile babel and then sit in the background and on file modification
+This will compile Babel and then sit in the background and on file modification
 recompile the necessary files.
 
 #### Running tests
@@ -31,8 +31,6 @@ You can run tests via:
 $ make test
 ```
 
-This will usually take around two minutes as it's compiling the entire
-[test262](https://github.com/tc39/test262) test suite and validating its AST.
 This is mostly overkill and you can limit the tests to a select few by directly
 running them with `mocha`:
 

Makefile

@@ -32,7 +32,7 @@ build:
 	node $(BROWSERIFY_CMD) lib/babel/api/browser.js -s babel >dist/babel.js
 	node $(UGLIFY_CMD) dist/babel.js >dist/babel.min.js
 
-	node bin/babel-external-helpers >dist/external-helpers.js
+	node packages/babel-cli/bin/babel-external-helpers >dist/external-helpers.js
 	node $(UGLIFY_CMD) dist/external-helpers.js >dist/external-helpers.min.js
 
 	rm -rf templates.json
@@ -87,11 +87,11 @@ publish:
 	node tools/cache-templates
 	test -f templates.json
 
-	npm publish --tag beta
+	npm publish
 
 	git push --follow-tags
 
-	make publish-core
+	make publish-cli
 	make publish-runtime
 
 	rm -rf templates.json browser.js browser-polyfill.js external-helpers.js
@@ -100,20 +100,18 @@ publish-runtime:
 	cd packages; \
 	node build-runtime.js; \
 	cd babel-runtime; \
-	npm publish --tag beta
+	npm publish
 
-publish-core:
-	tools/generate-core-package-json >package2.json
-	mv package.json .package.json
-	mv package2.json package.json
-
-	npm publish --tag beta
-
-	rm -rf package.json
-	mv .package.json package.json
+publish-cli:
+	cd packages; \
+	node build-cli.js; \
+	cd babel-cli; \
+	npm publish
 
 bootstrap:
 	npm install
+	npm link
+	cd packages/babel-cli && npm install && npm link
 	git submodule update --init
 	cd vendor/regenerator && npm install
 	cd vendor/compat-table && npm install object-assign

package.json

@@ -1,20 +1,14 @@
 {
-  "name": "babel",
+  "name": "babel-core",
   "description": "Turn ES6 code into readable vanilla ES5 with source maps",
-  "version": "5.0.0-beta4",
+  "version": "5.0.2",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://babeljs.io/",
   "repository": "babel/babel",
-  "preferGlobal": true,
   "main": "lib/babel/api/node.js",
   "browser": {
     "./lib/babel/api/register/node.js": "./lib/babel/api/register/browser.js"
   },
-  "bin": {
-    "babel": "./bin/babel/index.js",
-    "babel-node": "./bin/babel-node",
-    "babel-external-helpers": "./bin/babel-external-helpers"
-  },
   "keywords": [
     "harmony",
     "classes",
@@ -35,10 +29,8 @@
   "dependencies": {
     "ast-types": "~0.7.0",
     "chalk": "^1.0.0",
-    "chokidar": "^0.12.6",
-    "commander": "^2.6.0",
     "convert-source-map": "^0.5.0",
-    "core-js": "^0.6.0",
+    "core-js": "^0.8.0",
     "debug": "^2.1.1",
     "detect-indent": "^3.0.0",
     "estraverse": "^1.9.1",

packages/README.md

@@ -1,6 +0,0 @@
-# What is this?
-
-This is a folder containing additional packages that are built whenever
-a new version of babel is released.
-
-**TODO:** Move `babel-core` into here.

packages/babel-cli/bin/_babel-node

@@ -3,10 +3,10 @@
 var pathIsAbsolute = require("path-is-absolute");
 var commander      = require("commander");
 var Module         = require("module");
-var babel          = require("../lib/babel/api/node");
+var babel          = require("babel-core");
 var path           = require("path");
 var repl           = require("repl");
-var util           = require("../lib/babel/util");
+var util           = require("babel-core").util;
 var vm             = require("vm");
 var _              = require("lodash");
 

packages/babel-cli/bin/babel-external-helpers

@@ -1,8 +1,8 @@
 #!/usr/bin/env node
 
 var commander = require("commander");
-var util      = require("../lib/babel/util");
-var runtime   = require("../lib/babel/tools/build-external-helpers");
+var util      = require("babel-core").util;
+var runtime   = require("babel-core").buildExternalHelpers;
 
 commander.option("-l, --whitelist [whitelist]", "Whitelist of helpers to ONLY include", util.list);
 commander.option("-t, --output-type [type]", "Type of output (global|umd|var)", "global");

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

@@ -1,15 +1,15 @@
 #!/usr/bin/env node
 
 var commander = require("commander");
-var transform = require("../../lib/babel/transformation");
+var transform = require("babel-core").transform;
 var kebabCase = require("lodash/string/kebabCase");
-var File      = require("../../lib/babel/transformation/file");
-var util      = require("../../lib/babel/util");
+var options   = require("babel-core").options;
+var util      = require("babel-core").util;
 var each      = require("lodash/collection/each");
 var keys      = require("lodash/object/keys");
 var fs        = require("fs");
 
-each(File.options, function (option, key) {
+each(options, function (option, key) {
   if (option.hidden) return;
 
   var arg = kebabCase(key);
@@ -104,7 +104,7 @@ if (errors.length) {
 
 exports.opts = {};
 
-each(File.options, function (opt, key) {
+each(options, function (opt, key) {
   exports.opts[key] = commander[key];
 });
 

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

@@ -1,7 +1,7 @@
 var readdir = require("fs-readdir-recursive");
 var index   = require("./index");
-var babel   = require("../../lib/babel/api/node");
-var util    = require("../../lib/babel/util");
+var babel   = require("babel-core");
+var util    = require("babel-core").util;
 var path    = require("path");
 var fs      = require("fs");
 var _       = require("lodash");

packages/babel-cli/index.js

@@ -0,0 +1 @@
+module.exports = require("babel-core");

packages/babel-cli/package.json

@@ -0,0 +1,25 @@
+{
+  "name": "babel",
+  "description": "Turn ES6 code into readable vanilla ES5 with source maps",
+  "version": "5.0.1",
+  "author": "Sebastian McKenzie <sebmck@gmail.com>",
+  "homepage": "https://babeljs.io/",
+  "repository": "babel/babel",
+  "preferGlobal": true,
+  "dependencies": {
+    "chokidar": "^0.12.6",
+    "babel-core": "^5.0.1",
+    "commander": "^2.6.0",
+    "fs-readdir-recursive": "^0.1.0",
+    "output-file-sync": "^1.1.0",
+    "lodash": "^3.2.0",
+    "convert-source-map": "^0.5.0",
+    "source-map": "^0.4.0",
+    "path-is-absolute": "^1.0.0"
+  },
+  "bin": {
+    "babel": "./bin/babel/index.js",
+    "babel-node": "./bin/babel-node",
+    "babel-external-helpers": "./bin/babel-external-helpers"
+  }
+}

packages/babel-cli/polyfill.js

@@ -0,0 +1 @@
+module.exports = require("babel-core/polyfill");

packages/babel-cli/register.js

@@ -0,0 +1 @@
+module.exports = require("babel-core/register");

packages/babel-runtime/es3/core-js.js

@@ -1,4 +0,0 @@
-module.exports = {
-  "default": require("core-js/client/library"),
-  __esModule: true
-};

packages/babel-runtime/package.json

@@ -1,10 +1,10 @@
 {
   "name": "babel-runtime",
   "description": "babel selfContained runtime",
-  "version": "5.0.0-beta3",
+  "version": "5.0.1",
   "repository": "babel/babel",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "dependencies": {
-    "core-js": "^0.6.0"
+    "core-js": "^0.8.0"
   }
-}
+}

packages/build-cli.js

@@ -0,0 +1,11 @@
+var outputFile = require("output-file-sync");
+
+var pkgLoc = __dirname + "/babel-cli/package.json";
+var pkg    = require(pkgLoc);
+
+var mainPkg = require("../package.json");
+
+pkg.version = mainPkg.version;
+pkg.dependencies["babel-core"] = "^" + mainPkg.version;
+
+outputFile(pkgLoc, JSON.stringify(pkg, null, 2));

packages/build-runtime.js

@@ -39,39 +39,34 @@ function writeRootFile(filename, content) {
   outputFile(filename, content);
 }
 
-function doVersion(version) {
-  var transformer = version + ".runtime";
 
-  function writeFile(filename, content) {
-    return writeRootFile(version + "/" + filename, content);
-  }
-
-  function selfContainify(code) {
-    return transform(code, {
-      optional: [transformer]
-    }).code;
-  }
-
-  function buildHelper(helperName) {
-    var tree = t.program(
-      util.template("self-contained-helpers-head", {
-        HELPER: util.template("helper-" + helperName)
-      })
-    );
-
-    return transform.fromAst(tree, null, {
-      optional: [transformer]
-    }).code;
-  }
-
-  each(File.helpers, function (helperName) {
-    writeFile("helpers/" + helperName + ".js", buildHelper(helperName));
-  });
-
-  writeFile("regenerator/index.js", readFile("regenerator-babel/runtime-module", true));
-  writeFile("regenerator/runtime.js", selfContainify(readFile("regenerator-babel/runtime")));
+function writeFile(filename, content) {
+  return writeRootFile(filename, content);
 }
 
-doVersion("es3");
-doVersion("es5");
+function selfContainify(code) {
+  return transform(code, {
+    optional: ["runtime"]
+  }).code;
+}
+
+function buildHelper(helperName) {
+  var tree = t.program(
+    util.template("self-contained-helpers-head", {
+      HELPER: util.template("helper-" + helperName)
+    })
+  );
+
+  return transform.fromAst(tree, null, {
+    optional: ["runtime"]
+  }).code;
+}
+
+each(File.helpers, function (helperName) {
+  writeFile("helpers/" + helperName + ".js", buildHelper(helperName));
+});
+
+writeFile("regenerator/index.js", readFile("regenerator-babel/runtime-module", true));
+writeFile("regenerator/runtime.js", selfContainify(readFile("regenerator-babel/runtime")));
+
 updatePackage();

src/acorn/src/expression.js

@@ -272,11 +272,13 @@ pp.parseExprAtom = function(refShorthandDefaultPos) {
         // arrow functions
         if (this.type === tt.parenL) {
           let expr = this.parseParenAndDistinguishExpression(start, true)
-          if (expr.type === "ArrowFunctionExpression") {
+          if (expr && expr.type === "ArrowFunctionExpression") {
             return expr
           } else {
             node.callee = id
-            if (expr.type === "SequenceExpression") {
+            if (!expr) {
+              node.arguments = []
+            } else if (expr.type === "SequenceExpression") {
               node.arguments = expr.expressions
             } else {
               node.arguments = [expr]
@@ -410,7 +412,13 @@ pp.parseParenAndDistinguishExpression = function(start, isAsync) {
       return this.parseParenArrowList(start, exprList, isAsync)
     }
 
-    if (!exprList.length) this.unexpected(this.lastTokStart)
+    if (!exprList.length) {
+      if (isAsync) {
+        return
+      } else {
+        this.unexpected(this.lastTokStart)
+      }
+    }
     if (spreadStart) this.unexpected(spreadStart)
     if (refShorthandDefaultPos.start) this.unexpected(refShorthandDefaultPos.start)
 

src/acorn/src/statement.js

@@ -558,9 +558,10 @@ pp.parseClassSuper = function(node) {
 pp.parseExport = function(node) {
   this.next()
   // export * from '...'
-  if (this.eat(tt.star)) {
+  if (this.type === tt.star) {
+    let specifier = this.startNode()
+    this.next()
     if (this.options.features["es7.exportExtensions"] && this.eatContextual("as")) {
-      let specifier = this.startNode()
       specifier.exported = this.parseIdent()
       node.specifiers = [this.finishNode(specifier, "ExportNamespaceSpecifier")]
       this.parseExportSpecifiersMaybe(node)
@@ -573,7 +574,16 @@ pp.parseExport = function(node) {
     let specifier = this.startNode()
     specifier.exported = this.parseIdent(true)
     node.specifiers = [this.finishNode(specifier, "ExportDefaultSpecifier")]
-    this.parseExportSpecifiersMaybe(node)
+    if (this.type === tt.comma && this.lookahead().type === tt.star) {
+      this.expect(tt.comma)
+      let specifier = this.startNode()
+      this.expect(tt.star)
+      this.expectContextual("as")
+      specifier.exported = this.parseIdent()
+      node.specifiers.push(this.finishNode(specifier, "ExportNamespaceSpecifier"))
+    } else {
+      this.parseExportSpecifiersMaybe(node)
+    }
     this.parseExportFrom(node)
   } else if (this.eat(tt._default)) { // export default ...
     let expr = this.parseMaybeAssign()

src/babel/api/browser.js

@@ -1,5 +1,6 @@
 var transform = module.exports = require("../transformation");
 
+transform.options = require("../transformation/file/options");
 transform.version = require("../../../package").version;
 
 transform.transform = transform;

src/babel/api/node.js

@@ -4,10 +4,9 @@ import * as acorn from "../../acorn";
 import * as util from "../util";
 import fs from "fs";
 
-export { util };
+export { util, acorn };
 export { canCompile } from "../util";
 
-export { acorn } from "../../acorn";
 export { default as options } from "../transformation/file/options";
 export { default as Transformer } from "../transformation/transformer";
 export { default as transform } from "../transformation";

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

@@ -50,9 +50,9 @@ function buildVar(namespace, builder) {
   return t.program(body);
 }
 
-function buildHelpers(body, namespace, whitelist = []) {
+function buildHelpers(body, namespace, whitelist) {
   each(File.helpers, function (name) {
-    if (whitelist.length && whitelist.indexOf(name) === -1) return;
+    if (whitelist && whitelist.indexOf(name) === -1) return;
 
     var key = t.identifier(t.toIdentifier(name));
     body.push(t.expressionStatement(

src/babel/transformation/file/index.js

@@ -173,20 +173,15 @@ export default class File {
     return includes(this.opts.loose, key);
   }
 
-  buildPlugins(stack) {
-
-  }
-
   buildTransformers() {
     var file = this;
 
-    var transformers = {};
+    var transformers = this.transformers = {};
 
     var secondaryStack = [];
     var stack = [];
 
-    this.buildPlugins(stack);
-
+    // build internal transformers
     each(transform.transformers, function (transformer, key) {
       var pass = transformers[key] = transformer.buildPass(file);
 
@@ -203,15 +198,23 @@ export default class File {
       }
     });
 
+    // init plugins!
+    var beforePlugins = [];
+    var afterPlugins = [];
+    for (var i = 0; i < file.opts.plugins.length; i++) {
+      this.addPlugin(file.opts.plugins[i], beforePlugins, afterPlugins);
+    }
+    stack = beforePlugins.concat(stack, afterPlugins);
+
+    // register
     this.transformerStack = stack.concat(secondaryStack);
-    this.transformers = transformers;
   }
 
   getModuleFormatter(type: string) {
     var ModuleFormatter = isFunction(type) ? type : transform.moduleFormatters[type];
 
     if (!ModuleFormatter) {
-      var loc = util.resolve(type);
+      var loc = util.resolveRelative(type);
       if (loc) ModuleFormatter = require(loc);
     }
 
@@ -222,6 +225,57 @@ export default class File {
     return new ModuleFormatter(this);
   }
 
+  addPlugin(name, before, after) {
+    var position = "before";
+    var plugin;
+
+    if (name) {
+      if (typeof name === "string") {
+        // this is a plugin in the form of "foobar" or "foobar:after"
+        // where the optional colon is the delimiter for plugin position in the transformer stack
+
+        [name, position = "before"] = name.split(":");
+
+        var loc = util.resolveRelative(name) || util.resolveRelative(`babel-plugin-${name}`);
+        if (loc) {
+          plugin = require(loc)
+        } else {
+          throw new ReferenceError(`Unknown plugin ${JSON.stringify(name)}`);
+        }
+      } else {
+        // not a string so we'll just assume that it's a direct Transformer instance, if not then
+        // the checks later on will complain
+        plugin = name;
+      }
+    } else {
+      throw new TypeError(`Ilegal kind ${typeof name} for plugin name ${JSON.stringify(name)}`);
+    }
+
+    // validate position
+    if (position !== "before" && position !== "after") {
+      throw new TypeError(`Plugin ${JSON.stringify(name)} has an illegal position of ${JSON.stringify(position)}`);
+    }
+
+    // validate transformer key
+    var key = plugin.key;
+    if (this.transformers[key]) {
+      throw new ReferenceError(`The key for plugin ${JSON.stringify(name)} of ${key} collides with an existing plugin`);
+    }
+
+    // validate Transformer instance
+    if (!plugin.buildPass || plugin.constructor.name !== "Transformer") {
+      throw new TypeError(`Plugin ${JSON.stringify(name)} didn't export default a Transformer instance`);
+    }
+
+    // build!
+    var pass = this.transformers[key] = plugin.buildPass(this);
+    if (pass.canTransform()) {
+      var stack = before;
+      if (position === "after") stack = after;
+      stack.push(pass);
+    }
+  }
+
   parseInputSourceMap(code: string) {
     var opts = this.opts;
 
@@ -292,6 +346,7 @@ export default class File {
 
       if (this.transformers["es6.modules"].canTransform()) {
         this.moduleFormatter.importSpecifier(specifiers[0], declar, this.dynamicImports);
+        this.moduleFormatter.hasLocalImports = true;
       } else {
         this.dynamicImports.push(declar);
       }
@@ -386,9 +441,10 @@ export default class File {
   parse(code: string) {
     if (this.shouldIgnore()) {
       return {
-        code: code,
-        map:  null,
-        ast:  null
+        metadata: {},
+        code:     code,
+        map:      null,
+        ast:      null
       };
     }
 
@@ -521,13 +577,14 @@ export default class File {
     var ast  = this.ast;
 
     var result = {
-      code: "",
-      map:  null,
-      ast:  null
+      metadata: {},
+      code:     "",
+      map:      null,
+      ast:      null
     };
 
-    if (this.opts.returnUsedHelpers) {
-      result.usedHelpers = Object.keys(this.usedHelpers);
+    if (this.opts.metadataUsedHelpers) {
+      result.metadata.usedHelpers = Object.keys(this.usedHelpers);
     }
 
     if (opts.ast) result.ast = ast;

src/babel/transformation/file/options.json

@@ -98,6 +98,11 @@
     "shorthand": "P"
   },
 
+  "plugins": {
+    "type": "list",
+    "description": ""
+  },
+
   "ignore": {
     "type": "list",
     "description": "list of glob paths to **not** compile"
@@ -127,7 +132,7 @@
   },
 
   "compact": {
-    "type": "booleanstring",
+    "type": "booleanString",
     "default": "auto",
     "description": "do not include superfluous whitespace characters and line terminators [true|false|auto]"
   },
@@ -153,7 +158,7 @@
     "description": "uses a reference to `babelHelpers` instead of placing helpers at the top of your code."
   },
 
-  "returnUsedHelpers": {
+  "metadataUsedHelpers": {
     "type": "boolean",
     "default": false,
     "hidden": true

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

@@ -144,10 +144,14 @@ export default function (exports, opts) {
   };
 
   exports.JSXElement = {
+    enter(node) {
+      node.children = react.buildChildren(node);
+    },
+
     exit(node) {
       var callExpr = node.openingElement;
 
-      callExpr.arguments = callExpr.arguments.concat(react.buildChildren(node));
+      callExpr.arguments = callExpr.arguments.concat(node.children);
 
       if (callExpr.arguments.length >= 3) {
         callExpr._prettyCall = true;

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

@@ -1,101 +0,0 @@
-import includes from "lodash/collection/includes";
-import * as util from  "../../util";
-import has from "lodash/object/has";
-import * as t from "../../types";
-
-var isSymbolIterator = t.buildMatchMemberExpression("Symbol.iterator");
-
-var ALIASABLE_CONSTRUCTORS = [
-  "Symbol",
-  "Promise",
-  "Map",
-  "WeakMap",
-  "Set",
-  "WeakSet"
-];
-
-export default function (exports, core, prefix) {
-  var moduleName = `babel-runtime/${prefix}`;
-
-  function coreHas(node) {
-    return node.name !== "_" && has(core, node.name);
-  }
-
-  var astVisitor = {
-    enter(node, parent, scope, file) {
-      var prop;
-
-      if (this.isMemberExpression() && this.isReferenced()) {
-        // Array.from -> _core.Array.from
-        var obj = node.object;
-        prop = node.property;
-
-        if (!t.isReferenced(obj, node)) return;
-
-        if (!node.computed && coreHas(obj) && has(core[obj.name], prop.name) && !scope.getBindingIdentifier(obj.name)) {
-          this.skip();
-          return t.prependToMemberExpression(node, file.get("coreIdentifier"));
-        }
-      } else if (this.isReferencedIdentifier() && !t.isMemberExpression(parent) && includes(ALIASABLE_CONSTRUCTORS, node.name) && !scope.getBindingIdentifier(node.name)) {
-        // Symbol() -> _core.Symbol(); new Promise -> new _core.Promise
-        return t.memberExpression(file.get("coreIdentifier"), node);
-      } else if (this.isCallExpression()) {
-        // arr[Symbol.iterator]() -> _core.$for.getIterator(arr)
-
-        var callee = node.callee;
-        if (node.arguments.length) return false;
-
-        if (!t.isMemberExpression(callee)) return false;
-        if (!callee.computed) return false;
-
-        prop = callee.property;
-        if (!isSymbolIterator(prop)) return false;
-
-        return util.template("corejs-iterator", {
-          CORE_ID: file.get("coreIdentifier"),
-          VALUE:   callee.object
-        });
-      } else if (this.isBinaryExpression()) {
-        // Symbol.iterator in arr -> core.$for.isIterable(arr)
-
-        if (node.operator !== "in") return;
-
-        var left = node.left;
-        if (!isSymbolIterator(left)) return;
-
-        return util.template("corejs-is-iterator", {
-          CORE_ID: file.get("coreIdentifier"),
-          VALUE:   node.right
-        });
-      }
-    }
-  };
-
-  exports.metadata = {
-    optional: true
-  };
-
-  exports.Program = function (node, parent, scope, file) {
-    this.traverse(astVisitor, file);
-  };
-
-  exports.pre = function (file) {
-    file.set("helperGenerator", function (name) {
-      return file.addImport(`${moduleName}/helpers/${name}`, name);
-    });
-
-    file.setDynamic("coreIdentifier", function () {
-      return file.addImport(`${moduleName}/core-js`, "core");
-    });
-
-    file.setDynamic("regeneratorIdentifier", function () {
-      return file.addImport(`${moduleName}/regenerator`, "regeneratorRuntime");
-    });
-  };
-
-  exports.Identifier = function (node, parent, scope, file) {
-    if (this.isReferencedIdentifier({ name: "regeneratorRuntime" })) {
-      return file.get("regeneratorIdentifier");
-    }
-  };
-};

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

@@ -25,13 +25,12 @@ var wrap = function (state, method, id, scope) {
     var template = util.template(templateName, {
       FUNCTION: method,
       FUNCTION_ID: id,
-      FUNCTION_KEY: scope.generateUidIdentifier(id.name),
-      WRAPPER_KEY: scope.generateUidIdentifier(id.name + "Wrapper")
+      FUNCTION_KEY: scope.generateUidIdentifier(id.name)
     });
 
     // shim in dummy params to retain function arity, if you try to read the
     // source then you'll get the original since it's proxied so it's all good
-    var params = template.callee.body.body[0].declarations[0].init.params;
+    var params = template.callee.body.body[0].params;
     for (var i = 0, len = getFunctionArity(method); i < len; i++) {
       params.push(scope.generateUidIdentifier("x"));
     }

src/babel/transformation/helpers/react.js

@@ -81,15 +81,15 @@ export function buildChildren(node) {
 
   for (var i = 0; i < node.children.length; i++) {
     var child = node.children[i];
-    if (t.isJSXExpressionContainer(child)) child = child.expression;
 
     if (t.isLiteral(child) && typeof child.value === "string") {
       cleanJSXElementLiteralChild(child, elems);
       continue;
-    } else if (t.isJSXEmptyExpression(child)) {
-      continue;
     }
 
+    if (t.isJSXExpressionContainer(child)) child = child.expression;
+    if (t.isJSXEmptyExpression(child)) continue;
+
     elems.push(child);
   }
 

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

@@ -1,9 +1,6 @@
-module.exports = ReplaceSupers;
-
 import * as messages from "../../messages";
 import * as t from "../../types";
 
-
 function isIllegalBareSuper(node, parent) {
   if (!t.isSuper(node)) return false;
   if (t.isMemberExpression(parent, { computed: false })) return false;
@@ -11,6 +8,10 @@ function isIllegalBareSuper(node, parent) {
   return true;
 }
 
+function isMemberExpressionSuper(node) {
+  return t.isMemberExpression(node) && t.isSuper(node.object);
+}
+
 var visitor = {
   enter(node, parent, scope, state) {
     var topLevel = state.topLevel;
@@ -18,7 +19,7 @@ var visitor = {
 
     if (t.isFunction(node) && !t.isArrowFunctionExpression(node)) {
       // we need to call traverseLevel again so we're context aware
-      self.traverseLevel(node, false);
+      self.traverseLevel(this, false);
       return this.skip();
     }
 
@@ -35,7 +36,10 @@ var visitor = {
 
     var callback = self.specHandle;
     if (self.isLoose) callback = self.looseHandle;
-    return callback.call(self, this, getThisReference);
+    var result = callback.call(self, this, getThisReference);
+    if (result) this.hasSuper = true;
+    if (result === true) return;
+    return result;
   }
 };
 
@@ -47,6 +51,7 @@ export default class ReplaceSupers {
 
   constructor(opts: Object, inClass?: boolean = false) {
     this.topLevelThisReference = opts.topLevelThisReference;
+    this.methodPath            = opts.methodPath;
     this.methodNode            = opts.methodNode;
     this.superRef              = opts.superRef;
     this.isStatic              = opts.isStatic;
@@ -118,16 +123,16 @@ export default class ReplaceSupers {
    */
 
   replace() {
-    this.traverseLevel(this.methodNode.value, true);
+    this.traverseLevel(this.methodPath.get("value"), true);
   }
 
   /**
    * Description
    */
 
-  traverseLevel(node: Object, topLevel: boolean) {
+  traverseLevel(path: TraversalPath, topLevel: boolean) {
     var state = { self: this, topLevel: topLevel };
-    this.scope.traverse(node, visitor, state);
+    path.traverse(visitor, state);
   }
 
   /**
@@ -190,7 +195,6 @@ export default class ReplaceSupers {
   looseHandle(path: TraversalPath, getThisReference: Function) {
     var node = path.node;
     if (path.isSuper()) {
-      this.hasSuper = true;
       return this.getLooseSuperProperty(node, path.parent);
     } else if (path.isCallExpression()) {
       var callee = node.callee;
@@ -198,9 +202,31 @@ export default class ReplaceSupers {
       if (!t.isSuper(callee.object)) return;
 
       // super.test(); -> objectRef.prototype.MethodName.call(this);
-      this.hasSuper = true;
       t.appendToMemberExpression(callee, t.identifier("call"));
       node.arguments.unshift(getThisReference());
+      return true;
+    }
+  }
+
+  /**
+   * Description
+   */
+
+  specHandleAssignmentExpression(ref, path, node, getThisReference) {
+    if (node.operator === "=") {
+      // super.name = "val"; -> _set(Object.getPrototypeOf(objectRef.prototype), "name", this);
+      return this.setSuperProperty(node.left.property, node.right, node.left.computed, getThisReference());
+    } else {
+      // super.age += 2; -> var _ref = super.age; super.age = _ref + 2;
+      ref ||= path.scope.generateUidIdentifier("ref");
+      return [
+        t.variableDeclaration("var", [
+          t.variableDeclarator(ref, node.left)
+        ]),
+        t.expressionStatement(
+          t.assignmentExpression("=", node.left, t.binaryExpression(node.operator[0], ref, node.right))
+        )
+      ];
     }
   }
 
@@ -237,7 +263,7 @@ export default class ReplaceSupers {
           var methodName = methodNode.key.name || "METHOD_NAME";
           throw this.file.errorWithNode(node, messages.get("classesIllegalSuperCall", methodName));
         }
-      } else if (t.isMemberExpression(callee) && t.isSuper(callee.object)) {
+      } else if (isMemberExpressionSuper(callee)) {
         // super.test(); -> _get(Object.getPrototypeOf(objectRef.prototype), "test", this).call(this);
         property = callee.property;
         computed = callee.computed;
@@ -247,16 +273,22 @@ export default class ReplaceSupers {
       // super.name; -> _get(Object.getPrototypeOf(objectRef.prototype), "name", this);
       property = node.property;
       computed = node.computed;
-    } else if (t.isAssignmentExpression(node) && t.isSuper(node.left.object) && methodNode.kind === "set") {
-      // super.name = "val"; -> _set(Object.getPrototypeOf(objectRef.prototype), "name", this);
-      this.hasSuper = true;
-      return this.setSuperProperty(node.left.property, node.right, node.left.computed, getThisReference());
+    } else if (t.isUpdateExpression(node) && isMemberExpressionSuper(node.argument)) {
+      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);
+      } else {
+        // super.foo++; -> var _ref = super.foo; super.foo = _ref + 1;
+        var ref = path.scope.generateUidIdentifier("ref");
+        return this.specHandleAssignmentExpression(ref, path, binary, getThisReference).concat(t.expressionStatement(ref));
+      }
+    } else if (t.isAssignmentExpression(node) && isMemberExpressionSuper(node.left)) {
+      return this.specHandleAssignmentExpression(null, path, node, getThisReference);
     }
 
     if (!property) return;
 
-    this.hasSuper = true;
-
     thisReference = getThisReference();
     var superProperty = this.getSuperProperty(property, computed, thisReference);
     if (args) {

src/babel/transformation/modules/_default.js

@@ -7,37 +7,51 @@ import * as t from "../../types";
 
 var remapVisitor = {
   enter(node, parent, scope, formatter) {
-    if (t.isUpdateExpression(node) && formatter.isLocalReference(node.argument, scope)) {
-      this.skip();
-
-      // expand to long file assignment expression
-      var assign = t.assignmentExpression(node.operator[0] + "=", node.argument, t.literal(1));
-
-      // remap this assignment expression
-      var remapped = formatter.remapExportAssignment(assign);
-
-      // we don't need to change the result
-      if (t.isExpressionStatement(parent) || node.prefix) {
-        return remapped;
+    var remap = formatter.internalRemap[node.name];
+    if (this.isReferencedIdentifier() && remap) {
+      if (!scope.hasBinding(node.name) || scope.bindingIdentifierEquals(node.name, formatter.localImports[node.name])) {
+        return remap;
       }
-
-      var nodes = [];
-      nodes.push(remapped);
-
-      var operator;
-      if (node.operator === "--") {
-        operator = "+";
-      } else { // "++"
-        operator = "-";
-      }
-      nodes.push(t.binaryExpression(operator, node.argument, t.literal(1)));
-
-      return t.sequenceExpression(nodes);
     }
 
-    if (t.isAssignmentExpression(node) && formatter.isLocalReference(node.left, scope)) {
-      this.skip();
-      return formatter.remapExportAssignment(node);
+    if (t.isUpdateExpression(node)) {
+      var exported = formatter.getExport(node.argument, scope);
+
+      if (exported) {
+        this.skip();
+
+        // expand to long file assignment expression
+        var assign = t.assignmentExpression(node.operator[0] + "=", node.argument, t.literal(1));
+
+        // remap this assignment expression
+        var remapped = formatter.remapExportAssignment(assign, exported);
+
+        // we don't need to change the result
+        if (t.isExpressionStatement(parent) || node.prefix) {
+          return remapped;
+        }
+
+        var nodes = [];
+        nodes.push(remapped);
+
+        var operator;
+        if (node.operator === "--") {
+          operator = "+";
+        } else { // "++"
+          operator = "-";
+        }
+        nodes.push(t.binaryExpression(operator, node.argument, t.literal(1)));
+
+        return t.sequenceExpression(nodes);
+      }
+    }
+
+    if (t.isAssignmentExpression(node)) {
+      var exported = formatter.getExport(node.left, scope);
+      if (exported) {
+        this.skip();
+        return formatter.remapExportAssignment(node, exported);
+      }
     }
   }
 };
@@ -59,7 +73,21 @@ var exportsVisitor = traverse.explode({
 
       var declar = this.get("declaration");
       if (declar.isStatement()) {
-        extend(formatter.localExports, declar.getBindingIdentifiers());
+        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)) {
@@ -78,9 +106,12 @@ var exportsVisitor = traverse.explode({
 
 export default class DefaultFormatter {
   constructor(file) {
-    this.scope = file.scope;
-    this.file  = file;
-    this.ids   = object();
+    this.internalRemap = {};
+
+    this.defaultIds = object();
+    this.scope      = file.scope;
+    this.file       = file;
+    this.ids        = object();
 
     this.hasNonDefaultExports = false;
 
@@ -95,7 +126,7 @@ export default class DefaultFormatter {
     this.getLocalImports();
   }
 
-  init() {
+  transform() {
     this.remapAssignments();
   }
 
@@ -126,27 +157,35 @@ export default class DefaultFormatter {
     }
   }
 
-  isLocalReference(node) {
-    var localImports = this.localImports;
-    return t.isIdentifier(node) && localImports[node.name] && localImports[node.name] !== node;
+  remapExportAssignment(node, exported) {
+    var assign = node;
+
+    for (var i = 0; i < exported.length; i++) {
+      assign = t.assignmentExpression(
+        "=",
+        t.memberExpression(t.identifier("exports"), exported[i]),
+        assign
+      );
+    }
+
+    return assign;
   }
 
-  remapExportAssignment(node) {
-    return t.assignmentExpression(
-      "=",
-      node.left,
-      t.assignmentExpression(
-        node.operator,
-        t.memberExpression(t.identifier("exports"), node.left),
-        node.right
-      )
-    );
+  _addExport(name, exported) {
+    var info = this.localExports[name] ||= {
+      binding: this.scope.getBindingIdentifier(name),
+      exported: []
+    };
+    info.exported.push(exported);
   }
 
-  isLocalReference(node, scope) {
-    var localExports = this.localExports;
-    var name = node.name;
-    return t.isIdentifier(node) && localExports[name] && localExports[name] === scope.getBindingIdentifier(name);
+  getExport(node, scope) {
+    if (!t.isIdentifier(node)) return;
+
+    var local = this.localExports[node.name];
+    if (local && local.binding === scope.getBindingIdentifier(node.name)) {
+      return local.exported;
+    }
   }
 
   getModuleName() {
@@ -224,6 +263,10 @@ export default class DefaultFormatter {
     nodes.push(this.buildExportsWildcard(ref, node));
   }
 
+  isLoose() {
+    return this.file.isLoose("es6.modules");
+  }
+
   exportSpecifier(specifier, node, nodes) {
     if (node.source) {
       var ref = this.getExternalReference(node, nodes);
@@ -233,6 +276,11 @@ export default class DefaultFormatter {
         ref = t.callExpression(this.file.addHelper("interop-require"), [ref]);
       } else {
         ref = t.memberExpression(ref, specifier.local);
+
+        if (!this.isLoose()) {
+          nodes.push(this.buildExportsFromAssignment(specifier.exported, ref, node));
+          return;
+        }
       }
 
       // export { foo } from "test";
@@ -250,6 +298,14 @@ export default class DefaultFormatter {
     ]));
   }
 
+  buildExportsFromAssignment(id, init) {
+    this.checkExportIdentifier(id);
+    return util.template("exports-from-assign", {
+      INIT: init,
+      ID:   t.literal(id.name)
+    }, true);
+  }
+
   buildExportsAssignment(id, init) {
     this.checkExportIdentifier(id);
     return util.template("exports-assign", {

src/babel/transformation/modules/amd.js

@@ -21,6 +21,8 @@ export default class AMDFormatter extends DefaultFormatter {
    */
 
   transform(program) {
+    DefaultFormatter.prototype.transform.apply(this, arguments);
+
     var body = program.body;
 
     // build an array of module names
@@ -69,8 +71,13 @@ export default class AMDFormatter extends DefaultFormatter {
   }
 
   importSpecifier(specifier, node, nodes) {
+    var key = node.source.value;
     var ref = this.getExternalReference(node);
 
+    if (t.isImportNamespaceSpecifier(specifier) || t.isImportDefaultSpecifier(specifier)) {
+      this.defaultIds[key] = specifier.local;
+    }
+
     if (includes(this.file.dynamicImportedNoDefault, node)) {
       // Prevent unnecessary renaming of dynamic imports.
       this.ids[node.source.value] = ref;
@@ -78,7 +85,11 @@ export default class AMDFormatter extends DefaultFormatter {
       // import * as bar from "foo";
     } else if (!includes(this.file.dynamicImported, node) && t.isSpecifierDefault(specifier) && !this.noInteropRequireImport) {
       // import foo from "foo";
-      ref = t.callExpression(this.file.addHelper("interop-require"), [ref]);
+      var uid = this.scope.generateUidIdentifier(specifier.local.name);
+      nodes.push(t.variableDeclaration("var", [
+        t.variableDeclarator(uid, t.callExpression(this.file.addHelper("interop-require"), [ref]))
+      ]));
+      ref = uid;
     } else {
       // import { foo } from "foo";
       var imported = specifier.imported;
@@ -86,9 +97,7 @@ export default class AMDFormatter extends DefaultFormatter {
       ref = t.memberExpression(ref, imported);
     }
 
-    nodes.push(t.variableDeclaration("var", [
-      t.variableDeclarator(specifier.local, ref)
-    ]));
+    this.internalRemap[specifier.local.name] = ref;
   }
 
   exportSpecifier() {

src/babel/transformation/modules/common.js

@@ -9,15 +9,16 @@ export default class CommonJSFormatter extends DefaultFormatter {
     var scope = file.scope;
 
     scope.rename("module");
+    scope.rename("exports");
 
     if (!this.noInteropRequireImport && this.hasNonDefaultExports) {
       var templateName = "exports-module-declaration";
       if (this.file.isLoose("es6.modules")) templateName += "-loose";
-      file.ast.program.body.unshift(util.template(templateName, true));
+      var declar = util.template(templateName, true);
+      declar._blockHoist = 3;
+      file.ast.program.body.unshift(declar);
     }
-
-    DefaultFormatter.prototype.init.call(this);
-  };
+  }
 
   importSpecifier(specifier, node, nodes) {
     var variableName = specifier.local;
@@ -26,14 +27,17 @@ export default class CommonJSFormatter extends DefaultFormatter {
 
     // import foo from "foo";
     if (t.isSpecifierDefault(specifier)) {
-      if (!includes(this.file.dynamicImportedNoDefault, node)) {
-        if (this.noInteropRequireImport || includes(this.file.dynamicImported, node)) {
-          ref = t.memberExpression(ref, t.identifier("default"));
-        } else {
-          ref = t.callExpression(this.file.addHelper("interop-require"), [ref]);
+      if (includes(this.file.dynamicImportedNoDefault, node)) {
+        this.internalRemap[variableName.name] = ref;
+      } else {
+        if (this.noInteropRequireImport) {
+          this.internalRemap[variableName.name] = t.memberExpression(ref, t.identifier("default"))
+        } else if (!includes(this.file.dynamicImported, node)) {
+          nodes.push(t.variableDeclaration("var", [
+            t.variableDeclarator(variableName, t.callExpression(this.file.addHelper("interop-require"), [ref]))
+          ]));
         }
       }
-      nodes.push(t.variableDeclaration("var", [t.variableDeclarator(variableName, ref)]));
     } else {
       if (t.isImportNamespaceSpecifier(specifier)) {
         if (!this.noInteropRequireImport) {
@@ -46,12 +50,7 @@ export default class CommonJSFormatter extends DefaultFormatter {
         ]));
       } else {
         // import { foo } from "foo";
-        nodes.push(t.variableDeclaration("var", [
-          t.variableDeclarator(
-            variableName,
-            t.memberExpression(ref, specifier.imported)
-          )
-        ]));
+        this.internalRemap[variableName.name] = t.memberExpression(ref, specifier.imported);
       }
     }
   }
@@ -95,16 +94,21 @@ export default class CommonJSFormatter extends DefaultFormatter {
 
   _getExternalReference(node, nodes) {
     var source = node.source.value;
-    var call = t.callExpression(t.identifier("require"), [node.source]);
 
-    if (this.localImportOccurences[source] > 1) {
-      var uid = this.scope.generateUidIdentifier(source);
-      nodes.push(t.variableDeclaration("var", [
-        t.variableDeclarator(uid, call)
-      ]));
-      return uid;
+    var call = t.callExpression(t.identifier("require"), [node.source]);
+    var uid;
+
+    if (includes(this.file.dynamicImported, node) && !includes(this.file.dynamicImportedNoDefault, node)) {
+      call = t.memberExpression(call, t.identifier("default"));
+      uid = node.specifiers[0].local;
     } else {
-      return call;
+      uid = this.scope.generateUidBasedOnNode(node, "import");
     }
+
+    var declar = t.variableDeclaration("var", [
+      t.variableDeclarator(uid, call)
+    ]);
+    nodes.push(declar);
+    return uid;
   }
 }

src/babel/transformation/modules/system.js

@@ -94,12 +94,8 @@ export default class SystemFormatter extends AMDFormatter {
     DefaultFormatter.apply(this, arguments);
   }
 
-  init() {
-    DefaultFormatter.prototype.init.call(this);
-  }
-
   _addImportSource(node, exportNode) {
-    node._importSource = exportNode.source && exportNode.source.value;
+    if (node) node._importSource = exportNode.source && exportNode.source.value;
     return node;
   }
 
@@ -125,8 +121,18 @@ export default class SystemFormatter extends AMDFormatter {
     return this._addImportSource(call, node);
   }
 
-  remapExportAssignment(node) {
-    return this.buildExportCall(t.literal(node.left.name), node);
+  buildExportsFromAssignment() {
+    return this.buildExportsAssignment(...arguments);
+  }
+
+  remapExportAssignment(node, exported) {
+    var assign = node;
+
+    for (var i = 0; i < exported.length; i++) {
+      assign = this.buildExportCall(t.literal(exported[i].name), assign);
+    }
+
+    return assign;
   }
 
   buildExportCall(id, init, isStatement) {
@@ -140,6 +146,15 @@ export default class SystemFormatter extends AMDFormatter {
 
   importSpecifier(specifier, node, nodes) {
     AMDFormatter.prototype.importSpecifier.apply(this, arguments);
+
+    for (var name in this.internalRemap) {
+      nodes.push(t.variableDeclaration("var", [
+        t.variableDeclarator(t.identifier(name), this.internalRemap[name])
+      ]));
+    }
+
+    this.internalRemap = {};
+
     this._addImportSource(last(nodes), node);
   }
 
@@ -160,6 +175,8 @@ export default class SystemFormatter extends AMDFormatter {
   }
 
   transform(program) {
+    DefaultFormatter.prototype.transform.apply(this, arguments);
+
     var hoistDeclarators = [];
     var moduleName = this.getModuleName();
     var moduleNameLiteral = t.literal(moduleName);

src/babel/transformation/modules/umd.js

@@ -1,3 +1,4 @@
+import DefaultFormatter from "./_default";
 import AMDFormatter from "./amd";
 import values from "lodash/object/values";
 import * as util from  "../../util";
@@ -5,12 +6,14 @@ import * as t from "../../types";
 
 export default class UMDFormatter extends AMDFormatter {
   transform(program) {
+    DefaultFormatter.prototype.transform.apply(this, arguments);
+
     var body = program.body;
 
     // build an array of module names
 
     var names = [];
-    for (var name in this.ids) {
+    for (let name in this.ids) {
       names.push(t.literal(name));
     }
 
@@ -44,7 +47,13 @@ export default class UMDFormatter extends AMDFormatter {
 
     // globals
 
-    //var umdArgs = [];
+    var browserArgs = [t.memberExpression(t.identifier("module"), t.identifier("exports"))];
+    if (this.passModuleArg) browserArgs.push(t.identifier("module"));
+
+    for (let name in this.ids) {
+      var id = this.defaultIds[name] || t.identifier(t.toIdentifier(name));
+      browserArgs.push(t.memberExpression(t.identifier("global"), id));
+    }
 
     //
 
@@ -54,12 +63,15 @@ export default class UMDFormatter extends AMDFormatter {
     var runner = util.template("umd-runner-body", {
       AMD_ARGUMENTS: defineArgs,
       COMMON_TEST: commonTests,
-      COMMON_ARGUMENTS: commonArgs
+      COMMON_ARGUMENTS: commonArgs,
+      BROWSER_ARGUMENTS: browserArgs,
+      GLOBAL_ARG: t.identifier(t.toIdentifier(this.file.opts.basename))
     });
 
     //
 
-    var call = t.callExpression(runner, [factory]);
-    program.body = [t.expressionStatement(call)];
+    program.body = [t.expressionStatement(
+      t.callExpression(runner, [t.thisExpression(), factory])
+    )];
   }
 }

src/babel/transformation/templates/corejs-is-iterator.js

@@ -1 +1 @@
-CORE_ID.$for.isIterable(VALUE);
+CORE_ID.isIterable(VALUE);

src/babel/transformation/templates/corejs-iterator.js

@@ -1 +1 @@
-CORE_ID.$for.getIterator(VALUE);
+CORE_ID.getIterator(VALUE);

src/babel/transformation/templates/exports-from-assign.js

@@ -0,0 +1,6 @@
+Object.defineProperty(exports, ID, {
+  enumerable: true,
+  get: function () {
+    return INIT;
+  }
+});

src/babel/transformation/templates/helper-get.js

@@ -9,7 +9,7 @@
     } else {
       return get(parent, property, receiver);
     }
-  } else if ("value" in desc && desc.writable) {
+  } else if ("value" in desc) {
     return desc.value;
   } else {
     var getter = desc.get;

src/babel/transformation/templates/helper-set.js

@@ -5,15 +5,17 @@
     var parent = Object.getPrototypeOf(object);
 
     if (parent !== null) {
-      return set(parent, property, value, receiver);
+      set(parent, property, value, receiver);
     }
   } else if ("value" in desc && desc.writable) {
-    return desc.value = value;
+    desc.value = value;
   } else {
     var setter = desc.set;
 
     if (setter !== undefined) {
-      return setter.call(receiver, value);
+      setter.call(receiver, value);
     }
   }
+
+  return value;
 });

src/babel/transformation/templates/ludicrous-in.js

@@ -0,0 +1 @@
+Object(RIGHT)[LEFT] !== undefined;

src/babel/transformation/templates/property-method-assignment-wrapper-generator.js

@@ -1,11 +1,11 @@
 (function (FUNCTION_KEY) {
-  var WRAPPER_KEY = function* FUNCTION_ID() {
-    return yield* FUNCTION_KEY.apply(this, arguments);
+  function* FUNCTION_ID() {
+    return yield* FUNCTION_ID.apply(this, arguments);
+  }
+
+  FUNCTION_ID.toString = function () {
+    return FUNCTION_ID.toString();
   };
 
-  WRAPPER_KEY.toString = function () {
-    return FUNCTION_KEY.toString();
-  };
-
-  return WRAPPER_KEY;
+  return FUNCTION_ID;
 })(FUNCTION)

src/babel/transformation/templates/property-method-assignment-wrapper.js

@@ -1,11 +1,11 @@
 (function (FUNCTION_KEY) {
-  var WRAPPER_KEY = function FUNCTION_ID() {
+  function FUNCTION_ID() {
     return FUNCTION_KEY.apply(this, arguments);
-  };
+  }
 
-  WRAPPER_KEY.toString = function () {
-    return FUNCTION_KEY.toString();
-  };
+  FUNCTION_ID.toString = function () {
+    return FUNCTION_ID.toString();
+  }
 
-  return WRAPPER_KEY;
+  return FUNCTION_ID;
 })(FUNCTION)

src/babel/transformation/templates/umd-commonjs-strict.js

@@ -1,7 +1,7 @@
 (function (root, factory) {
   if (typeof define === "function" && define.amd) {
     define(AMD_ARGUMENTS, factory);
-  } else if (typeof exports === 'object') {
+  } else if (typeof exports === "object") {
     factory(COMMON_ARGUMENTS);
   } else {
     factory(BROWSER_ARGUMENTS);

src/babel/transformation/templates/umd-runner-body.js

@@ -1,7 +1,11 @@
-(function (factory) {
+(function (global, factory) {
   if (typeof define === "function" && define.amd) {
     define(AMD_ARGUMENTS, factory);
   } else if (COMMON_TEST) {
     factory(COMMON_ARGUMENTS);
+  } else {
+    var module = { exports: {} };
+    factory(BROWSER_ARGUMENTS);
+    global.GLOBAL_ARG = module.exports;
   }
 });

src/babel/transformation/transformer.js

@@ -9,7 +9,7 @@ import each from "lodash/collection/each";
 
 /**
  * This is the class responsible for normalising a transformers handlers
- * as well as constructing a `TransformerPass` that is repsonsible for
+ * as well as constructing a `TransformerPass` that is responsible for
  * actually running the transformer over the provided `File`.
  */
 
@@ -69,6 +69,11 @@ export default class Transformer {
   }
 
   buildPass(file: File): TransformerPass {
+    // validate Transformer instance
+    if (!(file instanceof File)) {
+      throw new TypeError(`Transformer ${this.key} is resolving to a different Babel version to what is doing the actual transformation...`);
+    }
+
     return new TransformerPass(file, this);
   }
 }

src/babel/transformation/transformers/es1/ludicrous.js

@@ -1,5 +0,0 @@
-import * as t from "../../../types";
-
-export var metadata = {
-  optional: true
-};

src/babel/transformation/transformers/es3/runtime.js

@@ -1,4 +0,0 @@
-import core from "core-js/client/library";
-import buildRuntimeTransformer from "../../helpers/build-runtime-transformer";
-
-buildRuntimeTransformer(exports, core, "es3");

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

@@ -70,13 +70,13 @@ export function Loop(node, parent, scope, file) {
     node.body._letDeclarators = [init];
   }
 
-  var blockScoping = new BlockScoping(this, node.body, parent, scope, file);
+  var blockScoping = new BlockScoping(this, this.get("body"), parent, scope, file);
   return blockScoping.run();
 }
 
 export function BlockStatement(block, parent, scope, file) {
   if (!t.isLoop(parent)) {
-    var blockScoping = new BlockScoping(null, block, parent, scope, file);
+    var blockScoping = new BlockScoping(null, this, parent, scope, file);
     blockScoping.run();
   }
 }
@@ -122,12 +122,14 @@ var letReferenceFunctionVisitor = {
     // not a direct reference
     if (!this.isReferencedIdentifier()) return;
 
+    var ref = state.letReferences[node.name];
+
     // not a part of our scope
-    if (!state.letReferences[node.name]) return;
+    if (!ref) return;
 
     // this scope has a variable with the same name so it couldn't belong
     // to our let scope
-    if (scope.hasOwnBinding(node.name)) return;
+    if (scope.getBindingIdentifier(node.name) !== ref) return;
 
     state.closurify = true;
   }
@@ -237,20 +239,23 @@ class BlockScoping {
    * Description
    */
 
-  constructor(loopPath?: TraversalPath, block: Object, parent: Object, scope: Scope, file: File) {
+  constructor(loopPath?: TraversalPath, blockPath: TraversalPath, parent: Object, scope: Scope, file: File) {
     this.parent = parent;
     this.scope  = scope;
-    this.block  = block;
     this.file   = file;
 
+    this.blockPath = blockPath;
+    this.block     = blockPath.node;
+
     this.outsideLetReferences = object();
     this.hasLetReferences     = false;
-    this.letReferences        = block._letReferences = object();
+    this.letReferences        = this.block._letReferences = object();
     this.body                 = [];
 
     if (loopPath) {
       this.loopParent = loopPath.parent;
       this.loopLabel  = t.isLabeledStatement(this.loopParent) && this.loopParent.label;
+      this.loopPath   = loopPath;
       this.loop       = loopPath.node;
     }
   }
@@ -326,7 +331,7 @@ class BlockScoping {
       traverseReplace(loop.update, loop, scope, remaps);
     }
 
-    scope.traverse(this.block, replaceVisitor, remaps);
+    this.blockPath.traverse(replaceVisitor, remaps);
   }
 
   /**
@@ -376,8 +381,17 @@ class BlockScoping {
     // replace the current block body with the one we're going to build
     block.body = this.body;
 
+    var ref = fn;
+
+    if (this.loop) {
+      ref = this.scope.generateUidIdentifier("loop");
+      this.loopPath.insertBefore(t.variableDeclaration("var", [
+        t.variableDeclarator(ref, fn)
+      ]));
+    }
+
     // build a call and a unique id that we can assign the return value to
-    var call = t.callExpression(fn, args);
+    var call = t.callExpression(ref, args);
     var ret  = this.scope.generateUidIdentifier("ret");
 
     // handle generators
@@ -394,7 +408,20 @@ class BlockScoping {
       call = t.awaitExpression(call);
     }
 
-    this.build(ret, call);
+    this.buildClosure(ret, call);
+  }
+
+  /**
+   * Push the closure to the body.
+   */
+
+  buildClosure(ret: { type: "Identifier" }, call: { type: "CallExpression" }) {
+    var has = this.has;
+    if (has.hasReturn || has.hasBreakContinue) {
+      this.buildHas(ret, call);
+    } else {
+      this.body.push(t.expressionStatement(call));
+    }
   }
 
   /**
@@ -474,7 +501,7 @@ class BlockScoping {
 
     // traverse through this block, stopping on functions and checking if they
     // contain any local let references
-    this.scope.traverse(this.block, letReferenceBlockVisitor, state);
+    this.blockPath.traverse(letReferenceBlockVisitor, state);
 
     return state.closurify;
   }
@@ -498,8 +525,8 @@ class BlockScoping {
       map:              {}
     };
 
-    this.scope.traverse(this.block, loopLabelVisitor, state);
-    this.scope.traverse(this.block, loopVisitor, state);
+    this.blockPath.traverse(loopLabelVisitor, state);
+    this.blockPath.traverse(loopVisitor, state);
 
     return state;
   }
@@ -510,7 +537,7 @@ class BlockScoping {
    */
 
   hoistVarDeclarations() {
-    traverse(this.block, hoistVarDeclarationsVisitor, this.scope, this);
+    this.blockPath.traverse(hoistVarDeclarationsVisitor, this);
   }
 
   /**
@@ -536,19 +563,6 @@ class BlockScoping {
     return replace;
   }
 
-  /**
-   * Push the closure to the body.
-   */
-
-  build(ret: { type: "Identifier" }, call: { type: "CallExpression" }) {
-    var has = this.has;
-    if (has.hasReturn || has.hasBreakContinue) {
-      this.buildHas(ret, call);
-    } else {
-      this.body.push(t.expressionStatement(call));
-    }
-  }
-
   /**
    * Description
    */

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

@@ -147,7 +147,7 @@ class ClassTransformer {
     if (this.hasSuper) {
       closureArgs.push(superName);
 
-      superName = this.scope.generateUidBasedOnNode(superName, this.file);
+      superName = this.scope.generateUidBasedOnNode(superName);
       closureParams.push(superName);
 
       this.superName = superName;
@@ -279,6 +279,7 @@ class ClassTransformer {
         if (isConstructor) this.verifyConstructor(path);
 
         var replaceSupers = new ReplaceSupers({
+          methodPath: path,
           methodNode: node,
           objectRef:  this.classRef,
           superRef:   this.superName,

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

@@ -33,8 +33,12 @@ export function ForOfStatement(node, parent, scope, file) {
 
   t.inherits(loop, node);
 
-  if (build.replaceParent) this.parentPath.replaceWithMultiple(build.node);
-  return build.node;
+  if (build.replaceParent) {
+    this.parentPath.replaceWithMultiple(build.node);
+    this.remove();
+  } else {
+    this.replaceWithMultiple(build.node);
+  }
 }
 
 export function _ForOfStatementArray(node, scope, file) {

src/babel/transformation/transformers/es6/object-super.js

@@ -3,7 +3,7 @@ import * as t from "../../../types";
 
 export var check = t.isSuper;
 
-function Property(node, scope, getObjectRef, file) {
+function Property(path, node, scope, getObjectRef, file) {
   if (!node.method) return;
 
   var value = node.value;
@@ -13,6 +13,7 @@ function Property(node, scope, getObjectRef, file) {
     topLevelThisReference: thisExpr,
     getObjectRef:          getObjectRef,
     methodNode:            node,
+    methodPath:            path,
     isStatic:              true,
     scope:                 scope,
     file:                  file
@@ -33,8 +34,9 @@ export function ObjectExpression(node, parent, scope, file) {
   var objectRef;
   var getObjectRef = () => objectRef ||= scope.generateUidIdentifier("obj");
 
+  var propPaths = this.get("properties");
   for (var i = 0; i < node.properties.length; i++) {
-    Property(node.properties[i], scope, getObjectRef, file);
+    Property(propPaths[i], node.properties[i], scope, getObjectRef, file);
   }
 
   if (objectRef) {

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

@@ -5,6 +5,8 @@ export var metadata = {
 };
 
 export function TemplateLiteral(node, parent, scope, file) {
+  if (t.isTaggedTemplateExpression(parent)) return;
+
   for (var i = 0; i < node.expressions.length; i++) {
     node.expressions[i] = t.callExpression(t.identifier("String"), [node.expressions[i]]);
   }

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

@@ -26,7 +26,7 @@ function generator(node) {
 }
 
 function array(node, parent, scope, file) {
-  var uid = scope.generateUidBasedOnNode(parent, file);
+  var uid = scope.generateUidBasedOnNode(parent);
 
   var container = util.template("array-comprehension-container", {
     KEY: uid

src/babel/transformation/transformers/es7/export-extensions.js

@@ -10,28 +10,32 @@ export function check(node) {
   return t.isExportDefaultSpecifier(node) || t.isExportNamespaceSpecifier(node);
 }
 
-export function ExportNamedDeclaration(node, parent, scope) {
-  var nodes = [];
+function build(node, nodes, scope) {
+  var first = node.specifiers[0];
+  if (!t.isExportNamespaceSpecifier(first) && !t.isExportDefaultSpecifier(first)) return;
 
-  if (t.isExportNamespaceSpecifier(node.specifiers[0])) {
-    var specifier = node.specifiers.shift();
-    var uid = scope.generateUidIdentifier(specifier.exported.name);
-    nodes.push(
-      t.importDeclaration([t.importNamespaceSpecifier(uid)], node.source),
-      t.exportNamedDeclaration(null, [t.exportSpecifier(uid, specifier.exported)])
-    );
-  } else if (t.isExportDefaultSpecifier(node.specifiers[0])) {
-    var specifier = node.specifiers.shift();
-    var uid = scope.generateUidIdentifier(specifier.exported.name);
-    nodes.push(
-      t.importDeclaration([t.importSpecifier(uid, specifier.exported)], node.source),
-      t.exportNamedDeclaration(null, [t.exportSpecifier(uid, t.identifier("default"))])
-    );
+  var specifier = node.specifiers.shift();
+  var uid = scope.generateUidIdentifier(specifier.exported.name);
+
+  var newSpecifier;
+  if (t.isExportNamespaceSpecifier(specifier)) {
+    newSpecifier = t.importNamespaceSpecifier(uid);
+  } else {
+    newSpecifier = t.importDefaultSpecifier(uid);
   }
 
+  nodes.push(t.importDeclaration([newSpecifier], node.source));
+  nodes.push(t.exportNamedDeclaration(null, [t.exportSpecifier(uid, specifier.exported)]));
+
+  build(node, nodes, scope);
+}
+
+export function ExportNamedDeclaration(node, parent, scope) {
+  var nodes = [];
+  build(node, nodes, scope);
   if (!nodes.length) return;
 
-  if (node.specifiers.length > 1) {
+  if (node.specifiers.length >= 1) {
     nodes.push(node);
   }
 

src/babel/transformation/transformers/index.js

@@ -83,7 +83,6 @@ export default {
   // needs to be after `regenerator` due to needing `regeneratorRuntime` references
   // needs to be after `es6.forOf` due to needing `Symbol.iterator` references
   // needs to be before `es6.modules` due to dynamic imports
-  "es3.runtime":                          require("./es3/runtime"),
   runtime:                                require("./other/runtime"),
 
   // needs to be before `_blockHoist` due to function hoisting etc
@@ -101,8 +100,8 @@ export default {
   "es7.doExpressions":                     require("./es7/do-expressions"),
 
   "es6.spec.symbols":                      require("./es6/spec.symbols"),
+  ludicrous:                               require("./other/ludicrous"),
   "spec.undefinedToVoid":                  require("./spec/undefined-to-void"),
-  "es1.ludicrous":                         require("./es1/ludicrous"),
 
   _strict:                                 require("./internal/strict"),
   _moduleFormatter:                        require("./internal/module-formatter"),

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

@@ -78,3 +78,19 @@ export function ExportNamedDeclaration(node, parent, scope) {
     return [declar, t.exportNamedDeclaration(null, specifiers)];
   }
 }
+
+export function Program(node) {
+  var imports = [];
+  var rest = [];
+
+  for (var i = 0; i < node.body.length; i++) {
+    var bodyNode = node.body[i];
+    if (t.isImportDeclaration(bodyNode)) {
+      imports.push(bodyNode);
+    } else {
+      rest.push(bodyNode);
+    }
+  }
+
+  node.body = imports.concat(rest);
+}

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

@@ -0,0 +1,29 @@
+import * as t from "../../../types";
+import * as util from "../../../util";
+
+export var metadata = {
+  optional: true
+};
+
+export function BinaryExpression(node) {
+  if (node.operator === "in") {
+    return util.template("ludicrous-in", {
+      LEFT: node.left,
+      RIGHT: node.right
+    });
+  }
+}
+
+export function Property(node) {
+  var key = node.key;
+  if (t.isLiteral(key) && typeof key.value === "number") {
+    key.value = "" + key.value;
+  }
+}
+
+export function Literal(node) {
+  if (node.regex) {
+    node.regex.pattern = "foobar";
+    node.regex.flags = "";
+  }
+}

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

@@ -1,4 +1,98 @@
 import core from "core-js/library";
-import buildRuntimeTransformer from "../../helpers/build-runtime-transformer";
+import includes from "lodash/collection/includes";
+import * as util from  "../../../util";
+import has from "lodash/object/has";
+import * as t from "../../../types";
 
-buildRuntimeTransformer(exports, core, "es5");
+var isSymbolIterator = t.buildMatchMemberExpression("Symbol.iterator");
+
+var ALIASABLE_CONSTRUCTORS = [
+"Symbol",
+"Promise",
+"Map",
+"WeakMap",
+"Set",
+"WeakSet"
+];
+
+function coreHas(node) {
+  return node.name !== "_" && has(core, node.name);
+}
+
+var astVisitor = {
+  enter(node, parent, scope, file) {
+    var prop;
+
+    if (this.isMemberExpression() && this.isReferenced()) {
+      // Array.from -> _core.Array.from
+      var obj = node.object;
+      prop = node.property;
+
+      if (!t.isReferenced(obj, node)) return;
+
+      if (!node.computed && coreHas(obj) && has(core[obj.name], prop.name) && !scope.getBindingIdentifier(obj.name)) {
+        this.skip();
+        return t.prependToMemberExpression(node, file.get("coreIdentifier"));
+      }
+    } else if (this.isReferencedIdentifier() && !t.isMemberExpression(parent) && includes(ALIASABLE_CONSTRUCTORS, node.name) && !scope.getBindingIdentifier(node.name)) {
+      // Symbol() -> _core.Symbol(); new Promise -> new _core.Promise
+      return t.memberExpression(file.get("coreIdentifier"), node);
+    } else if (this.isCallExpression()) {
+      // arr[Symbol.iterator]() -> _core.$for.getIterator(arr)
+
+      var callee = node.callee;
+      if (node.arguments.length) return false;
+
+      if (!t.isMemberExpression(callee)) return false;
+      if (!callee.computed) return false;
+
+      prop = callee.property;
+      if (!isSymbolIterator(prop)) return false;
+
+      return util.template("corejs-iterator", {
+        CORE_ID: file.get("coreIdentifier"),
+        VALUE:   callee.object
+      });
+    } else if (this.isBinaryExpression()) {
+      // Symbol.iterator in arr -> core.$for.isIterable(arr)
+
+      if (node.operator !== "in") return;
+
+      var left = node.left;
+      if (!isSymbolIterator(left)) return;
+
+      return util.template("corejs-is-iterator", {
+        CORE_ID: file.get("coreIdentifier"),
+        VALUE:   node.right
+      });
+    }
+  }
+};
+
+exports.metadata = {
+  optional: true
+};
+
+exports.Program = function (node, parent, scope, file) {
+  this.traverse(astVisitor, file);
+};
+
+exports.pre = function (file) {
+  file.set("helperGenerator", function (name) {
+    return file.addImport(`babel-runtime/helpers/${name}`, name);
+  });
+
+  file.setDynamic("coreIdentifier", function () {
+    return file.addImport("babel-runtime/core-js", "core");
+  });
+
+  file.setDynamic("regeneratorIdentifier", function () {
+    return file.addImport("babel-runtime/regenerator", "regeneratorRuntime");
+  });
+};
+
+exports.Identifier = function (node, parent, scope, file) {
+  if (this.isReferencedIdentifier({ name: "regeneratorRuntime" })) {
+    return file.get("regeneratorIdentifier");
+  }
+};

src/babel/transformation/transformers/spec/block-scoped-functions.js

@@ -1,12 +1,8 @@
 import * as t from "../../../types";
 
-export function BlockStatement(node, parent, scope, file) {
-  if ((t.isFunction(parent) && parent.body === node) || t.isExportDeclaration(parent)) {
-    return;
-  }
-
-  for (var i = 0; i < node.body.length; i++) {
-    var func = node.body[i];
+function statementList(key, node, file) {
+  for (var i = 0; i < node[key].length; i++) {
+    var func = node[key][i];
     if (!t.isFunctionDeclaration(func)) continue;
 
     var declar = t.variableDeclaration("let", [
@@ -19,8 +15,20 @@ export function BlockStatement(node, parent, scope, file) {
     // todo: name this
     func.id = null;
 
-    node.body[i] = declar;
+    node[key][i] = declar;
 
     file.checkNode(declar);
   }
 }
+
+export function BlockStatement(node, parent, scope, file) {
+  if ((t.isFunction(parent) && parent.body === node) || t.isExportDeclaration(parent)) {
+    return;
+  }
+
+  statementList("body", node, file);
+}
+
+export function SwitchCase(node, parent, scope, file) {
+  statementList("consequent", node, file);
+}

src/babel/traversal/index.js

@@ -7,7 +7,7 @@ export default function traverse(parent, opts, scope, state, parentPath) {
 
   if (!opts.noScope && !scope) {
     if (parent.type !== "Program" && parent.type !== "File") {
-      throw new Error(`Must pass a scope unless traversing a Program/File got a ${parent.type} node`);
+      throw new Error(`Must pass a scope and parentPath unless traversing a Program/File got a ${parent.type} node`);
     }
   }
 

src/babel/traversal/path/index.js

@@ -86,24 +86,26 @@ export default class TraversalPath {
   }
 
   insertBefore(nodes) {
+    nodes = this._verifyNodeList(nodes);
     this.checkNodes(nodes);
 
-    if (this.parentPath.isExpressionStatement()) {
+    if (this.parentPath.isExpressionStatement() || this.parentPath.isLabeledStatement()) {
       return this.parentPath.insertBefore(nodes);
     } else if (this.isPreviousType("Statement")) {
+      this._maybePopFromStatements(nodes);
       if (Array.isArray(this.container)) {
         this._containerInsertBefore(nodes);
       } else if (this.isStatementOrBlock()) {
         if (this.node) nodes.push(this.node);
         this.container[this.key] = t.blockStatement(nodes);
       } else {
-        throw new Error("no idea what to do with this");
+        throw new Error("We don't know what to do with this node type. We were previously a Statement but we can't fit in here?");
       }
     } else if (this.isPreviousType("Expression")) {
       if (this.node) nodes.push(this.node);
       this.replaceExpressionWithStatements(nodes);
     } else {
-      throw new Error("no idea what to do with this ");
+      throw new Error("No clue what to do with this node type.");
     }
   }
 
@@ -129,23 +131,36 @@ export default class TraversalPath {
     this._containerInsert(this.key + 1, nodes);
   }
 
+  _maybePopFromStatements(nodes) {
+    var last = nodes[nodes.length - 1];
+    if (t.isExpressionStatement(last) && t.isIdentifier(last.expression)) {
+      nodes.pop();
+    }
+  }
+
   isStatementOrBlock() {
-    return includes(t.STATEMENT_OR_BLOCK_KEYS, this.key) && !t.isBlockStatement(this.container);
+    if (t.isLabeledStatement(this.parent) || t.isBlockStatement(this.container)) {
+      return false;
+    } else {
+      return includes(t.STATEMENT_OR_BLOCK_KEYS, this.key);
+    }
   }
 
   insertAfter(nodes) {
+    nodes = this._verifyNodeList(nodes);
     this.checkNodes(nodes);
 
-    if (this.parentPath.isExpressionStatement()) {
+    if (this.parentPath.isExpressionStatement() || this.parentPath.isLabeledStatement()) {
       return this.parentPath.insertAfter(nodes);
     } else if (this.isPreviousType("Statement")) {
+      this._maybePopFromStatements(nodes);
       if (Array.isArray(this.container)) {
         this._containerInsertAfter(nodes);
       } else if (this.isStatementOrBlock()) {
         if (this.node) nodes.unshift(this.node);
         this.container[this.key] = t.blockStatement(nodes);
       } else {
-        throw new Error("no idea what to do with this");
+        throw new Error("We don't know what to do with this node type. We were previously a Statement but we can't fit in here?");
       }
     } else if (this.isPreviousType("Expression")) {
       if (this.node) {
@@ -155,7 +170,7 @@ export default class TraversalPath {
       }
       this.replaceExpressionWithStatements(nodes);
     } else {
-      throw new Error("no idea what to do with this");
+      throw new Error("No clue what to do with this node type.");
     }
   }
 
@@ -201,9 +216,9 @@ export default class TraversalPath {
       this.opts    = context.opts;
     }
 
-    this.setScope(file);
-
     this.type = this.node && this.node.type;
+
+    this.setScope(file);
   }
 
   _remove() {
@@ -216,6 +231,13 @@ export default class TraversalPath {
   }
 
   remove() {
+    var removeParent = false;
+    if (this.parentPath) {
+      removeParent ||= this.parentPath.isExpressionStatement();
+      removeParent ||= this.parentPath.isSequenceExpression() && this.parent.expressions.length === 1
+      if (removeParent) return this.parentPath.remove();
+    }
+
     this._remove();
     this.removed = true;
   }
@@ -251,7 +273,7 @@ export default class TraversalPath {
   replaceInline(nodes) {
     if (Array.isArray(nodes)) {
       if (Array.isArray(this.container)) {
-        this._verifyNodeList(nodes);
+        nodes = this._verifyNodeList(nodes);
         this._containerInsertAfter(nodes);
         return this.remove();
       } else {
@@ -263,20 +285,26 @@ export default class TraversalPath {
   }
 
   _verifyNodeList(nodes) {
-    if (typeof nodes === "object") {
+    if (nodes.constructor !== Array) {
       nodes = [nodes];
     }
 
     for (var i = 0; i < nodes.length; i++) {
       var node = nodes[i];
-      if (!node) throw new Error(`Node list has falsy node with the index of ${i}`);
+      if (!node) {
+        throw new Error(`Node list has falsy node with the index of ${i}`);
+      } else if (typeof node !== "object") {
+        throw new Error(`Node list contains a non-object node with the index of ${i}`);
+      } else if (!node.type) {
+        throw new Error(`Node list contains a node without a type with the index of ${i}`);
+      }
     }
 
     return nodes;
   }
 
   replaceWithMultiple(nodes: Array<Object>) {
-    this._verifyNodeList(nodes);
+    nodes = this._verifyNodeList(nodes);
     t.inheritsComments(nodes[0], this.node);
     this.container[this.key] = null;
     this.insertAfter(nodes);

src/babel/traversal/scope.js

@@ -57,7 +57,8 @@ var blockVariableVisitor = {
   enter(node, parent, scope, state) {
     if (this.isFunctionDeclaration() || this.isBlockScoped()) {
       state.registerDeclaration(this);
-    } else if (this.isScope()) {
+    }
+    if (this.isScope()) {
       this.skip();
     }
   }
@@ -100,7 +101,7 @@ export default class Scope {
    */
 
   traverse(node: Object, opts: Object, state?) {
-    traverse(node, opts, this, state);
+    traverse(node, opts, this, state, this.path);
   }
 
   /**
@@ -161,7 +162,7 @@ export default class Scope {
    * Description
    */
 
-  generateUidBasedOnNode(parent: Object):  Object {
+  generateUidBasedOnNode(parent: Object, defaultName?: String):  Object {
     var node = parent;
 
     if (t.isAssignmentExpression(parent)) {
@@ -175,7 +176,17 @@ export default class Scope {
     var parts = [];
 
     var add = function (node) {
-      if (t.isMemberExpression(node)) {
+      if (t.isModuleDeclaration(node)) {
+        if (node.specifiers && node.specifiers.length) {
+          for (var i = 0; i < node.specifiers.length; i++) {
+            add(node.specifiers[i]);
+          }
+        } else {
+          add(node.source);
+        }
+      } else if (t.isModuleSpecifier(node)) {
+        add(node.local);
+      } else if (t.isMemberExpression(node)) {
         add(node.object);
         add(node.property);
       } else if (t.isIdentifier(node)) {
@@ -195,7 +206,7 @@ export default class Scope {
     add(node);
 
     var id = parts.join("$");
-    id = id.replace(/^_/, "") || "ref";
+    id = id.replace(/^_/, "") || defaultName || "ref";
 
     return this.generateUidIdentifier(id);
   }
@@ -436,9 +447,6 @@ export default class Scope {
         var node = path.get(t.FOR_INIT_KEYS[i]);
         if (node.isBlockScoped()) this.registerBinding("let", node);
       }
-
-      var body = path.get("body");
-      if (body.isBlockStatement()) path = path.get("body");
     }
 
     // FunctionExpression - id

src/babel/types/alias-keys.json

@@ -15,6 +15,9 @@
   "LabeledStatement":         ["Statement"],
   "VariableDeclaration":      ["Statement", "Declaration"],
 
+  "ImportSpecifier":            ["ModuleSpecifier"],
+  "ExportSpecifier":            ["ModuleSpecifier"],
+  "ImportDefaultSpecifier":     ["ModuleSpecifier"],
   "ExportDefaultSpecifier":     ["ModuleSpecifier"],
   "ExportNamespaceSpecifier":   ["ModuleSpecifier"],
   "ExportDefaultFromSpecifier": ["ModuleSpecifier"],
@@ -27,9 +30,6 @@
   "FunctionDeclaration":     ["Scopable", "Function", "Statement", "Declaration"],
   "FunctionExpression":      ["Scopable", "Function", "Expression"],
 
-  "ImportSpecifier": ["ModuleSpecifier"],
-  "ExportSpecifier": ["ModuleSpecifier"],
-
   "BlockStatement": ["Scopable", "Statement"],
   "Program":        ["Scopable"],
   "CatchClause":    ["Scopable"],

src/babel/types/validators.js

@@ -106,7 +106,7 @@ export function isReferenced(node: Object, parent: Object): boolean {
  */
 
 export function isReferencedIdentifier(node: Object, parent: Object, opts?: Object): boolean {
-  return t.isIdentifier(node, opts) && t.isReferenced(node, parent);
+  return (t.isIdentifier(node, opts) || t.isJSXIdentifier(node, opts)) && t.isReferenced(node, parent);
 }
 
 /**
@@ -157,14 +157,8 @@ export function isSpecifierDefault(specifier: Object): boolean {
  */
 
 export function isScope(node: Object, parent: Object): boolean {
-  if (t.isBlockStatement(node)) {
-    if (t.isLoop(parent, { body: node })) {
-      return false;
-    }
-
-    if (t.isFunction(parent, { body: node })) {
-      return false;
-    }
+  if (t.isBlockStatement(node) && t.isFunction(parent, { body: node })) {
+    return false;
   }
 
   return t.isScopable(node);

src/babel/util.js

@@ -10,6 +10,7 @@ import contains from "lodash/collection/contains";
 import traverse from "./traversal";
 import isString from "lodash/lang/isString";
 import isRegExp from "lodash/lang/isRegExp";
+import Module from "module";
 import isEmpty from "lodash/lang/isEmpty";
 import parse from "./helpers/parse";
 import path from "path";
@@ -38,6 +39,21 @@ export function resolve(loc: string) {
   }
 }
 
+var relativeMod;
+
+export function resolveRelative(loc: string) {
+  if (!relativeMod) {
+    relativeMod = new Module;
+    relativeMod.paths = Module._nodeModulePaths(process.cwd());
+  }
+
+  try {
+    return Module._resolveFilename(loc, relativeMod);
+  } catch (err) {
+    return null;
+  }
+}
+
 export function list(val: string): Array<string> {
   return val ? val.split(",") : [];
 }
@@ -74,6 +90,7 @@ var templateVisitor = {
     if (t.isExpressionStatement(node)) {
       node = node.expression;
     }
+
     if (t.isIdentifier(node) && has(nodes, node.name)) {
       this.skip();
       this.replaceInline(nodes[node.name]);

test/core/api.js

@@ -33,5 +33,11 @@ suite("api", function () {
       assert.ok(script.indexOf("classCallCheck") === -1);
       assert.ok(script.indexOf("inherits") >= 0);
     });
+
+    test("empty whitelist", function () {
+      var script = buildExternalHelpers([]);
+      assert.ok(script.indexOf("classCallCheck") === -1);
+      assert.ok(script.indexOf("inherits") === -1);
+    });
   });
 });

test/core/bin.js

@@ -66,7 +66,7 @@ var assertTest = function (stdout, stderr, opts) {
 };
 
 var buildTest = function (binName, testName, opts) {
-  var binLoc = path.normalize(__dirname + "/../../bin/" + binName);
+  var binLoc = path.normalize(__dirname + "/../../packages/babel-cli/bin/" + binName);
 
   return function (callback) {
     this.timeout(5000);

test/core/browserify.js

@@ -12,7 +12,10 @@ suite("browserify", function() {
       assert.ok(bundle.length, "bundle output code");
 
       // ensure that the code runs without throwing an exception
-      vm.runInNewContext("var global = this;\n" + bundle, {});
+      vm.runInNewContext("var global = this;\n" + bundle, {
+        setInterval: function () {},
+        setTimeout: function () {}
+      });
       done();
     })
   })

test/core/fixtures/bin/babel-node/require/in-files/foo2.js

@@ -1,4 +1,4 @@
+import "./bar2";
+
 var foo = () => console.log("foo");
 foo();
-
-import "./bar2";

test/core/fixtures/bin/babel-node/require/stdout.txt

@@ -1,2 +1,2 @@
-foo
 bar
+foo

test/core/fixtures/transformation/api/resolve-module-source/expected.js

@@ -1,5 +1,5 @@
 "use strict";
 
-export { foo } from "resolved/foo-export-named";
 import foo from "resolved/foo-import-default";
 import "resolved/foo-import-bare";
+export { foo } from "resolved/foo-export-named";

test/core/fixtures/transformation/bluebird-coroutines/class/expected.js

@@ -1,6 +1,6 @@
 "use strict";
 
-var _bluebird = require("bluebird");
+var _bluebird2 = require("bluebird");
 
 var Foo = (function () {
   function Foo() {
@@ -9,7 +9,7 @@ var Foo = (function () {
 
   babelHelpers.createClass(Foo, [{
     key: "foo",
-    value: _bluebird.coroutine(function* () {
+    value: _bluebird2.coroutine(function* () {
       var wat = yield bar();
     })
   }]);

test/core/fixtures/transformation/bluebird-coroutines/expression/expected.js

@@ -1,7 +1,7 @@
 "use strict";
 
-var _bluebird = require("bluebird");
+var _bluebird2 = require("bluebird");
 
-var foo = _bluebird.coroutine(function* () {
+var foo = _bluebird2.coroutine(function* () {
   var wat = yield bar();
-});
+});

test/core/fixtures/transformation/bluebird-coroutines/named-expression/expected.js

@@ -1,10 +1,10 @@
 "use strict";
 
-var _bluebird = require("bluebird");
+var _bluebird2 = require("bluebird");
 
 var _bar;
 
-var foo = _bar = _bluebird.coroutine(function* () {
+var foo = _bar = _bluebird2.coroutine(function* () {
   console.log(_bar);
 });
 

test/core/fixtures/transformation/bluebird-coroutines/statement/expected.js

@@ -1,7 +1,7 @@
 "use strict";
 
-var _bluebird = require("bluebird");
+var _bluebird2 = require("bluebird");
 
-var foo = _bluebird.coroutine(function* () {
+var foo = _bluebird2.coroutine(function* () {
   var wat = yield bar();
-});
+});

test/core/fixtures/transformation/es3.runtime/aliases-array-is-array/actual.js

@@ -1 +0,0 @@
-Array.isArray(foo);

test/core/fixtures/transformation/es3.runtime/aliases-array-is-array/expected.js

@@ -1,5 +0,0 @@
-"use strict";
-
-var _core = require("babel-runtime/es3/core-js")["default"];
-
-_core.Array.isArray(foo);

test/core/fixtures/transformation/es3.runtime/options.json

@@ -1,4 +0,0 @@
-{
-  "optional": ["es3.runtime"],
-  "stage": 0
-}

test/core/fixtures/transformation/es6.block-scoping-exec/block-scoped-2.js

@@ -1,4 +1,4 @@
-assert.equal(() => {
+assert.equal((() => {
   let sum = 0;
   let a = 0;
   {
@@ -9,4 +9,4 @@ assert.equal(() => {
     }
   }
   return sum;
-}(), 10);
+})(), 10);

test/core/fixtures/transformation/es6.block-scoping/for-break-continue-return/expected.js

@@ -1,21 +1,23 @@
 "use strict";
 
 (function () {
+  var _loop = function (i) {
+    fns.push(function () {
+      return i;
+    });
+    if (i === 1) {
+      return "continue";
+    } else if (i === 2) {
+      return "break";
+    } else if (i === 3) {
+      return {
+        v: i
+      };
+    }
+  };
+
   _loop: for (var i in nums) {
-    var _ret = (function (i) {
-      fns.push(function () {
-        return i;
-      });
-      if (i === 1) {
-        return "continue";
-      } else if (i === 2) {
-        return "break";
-      } else if (i === 3) {
-        return {
-          v: i
-        };
-      }
-    })(i);
+    var _ret = _loop(i);
 
     switch (_ret) {
       case "continue":
@@ -28,4 +30,4 @@
         if (typeof _ret === "object") return _ret.v;
     }
   }
-})();
+})();

test/core/fixtures/transformation/es6.block-scoping/for-break/expected.js

@@ -1,12 +1,14 @@
 "use strict";
 
+var _loop = function (i) {
+  fns.push(function () {
+    return i;
+  });
+  return "break";
+};
+
 for (var i in nums) {
-  var _ret = (function (i) {
-    fns.push(function () {
-      return i;
-    });
-    return "break";
-  })(i);
+  var _ret = _loop(i);
 
   if (_ret === "break") break;
-}
+}

test/core/fixtures/transformation/es6.block-scoping/for-continuation/expected.js

@@ -1,12 +1,14 @@
 "use strict";
 
+var _loop = function (_i) {
+  (function () {
+    _i;
+  });
+  console.log(_i);
+  _i += 1;
+  i = _i;
+};
+
 for (var i = 0; i < 2; i++) {
-  (function (_i) {
-    (function () {
-      _i;
-    });
-    console.log(_i);
-    _i += 1;
-    i = _i;
-  })(i);
-}
+  _loop(i);
+}

test/core/fixtures/transformation/es6.block-scoping/for-continue/expected.js

@@ -1,12 +1,14 @@
 "use strict";
 
+var _loop = function (i) {
+  fns.push(function () {
+    return i;
+  });
+  return "continue";
+};
+
 for (var i in nums) {
-  var _ret = (function (i) {
-    fns.push(function () {
-      return i;
-    });
-    return "continue";
-  })(i);
+  var _ret = _loop(i);
 
   if (_ret === "continue") continue;
-}
+}

test/core/fixtures/transformation/es6.block-scoping/for-return-undefined/expected.js

@@ -1,16 +1,18 @@
 "use strict";
 
 (function () {
+  var _loop = function (i) {
+    fns.push(function () {
+      return i;
+    });
+    return {
+      v: undefined
+    };
+  };
+
   for (var i in nums) {
-    var _ret = (function (i) {
-      fns.push(function () {
-        return i;
-      });
-      return {
-        v: undefined
-      };
-    })(i);
+    var _ret = _loop(i);
 
     if (typeof _ret === "object") return _ret.v;
   }
-})();
+})();

test/core/fixtures/transformation/es6.block-scoping/for-return/expected.js

@@ -1,16 +1,18 @@
 "use strict";
 
 (function () {
+  var _loop = function (i) {
+    fns.push(function () {
+      return i;
+    });
+    return {
+      v: i
+    };
+  };
+
   for (var i in nums) {
-    var _ret = (function (i) {
-      fns.push(function () {
-        return i;
-      });
-      return {
-        v: i
-      };
-    })(i);
+    var _ret = _loop(i);
 
     if (typeof _ret === "object") return _ret.v;
   }
-})();
+})();

test/core/fixtures/transformation/es6.block-scoping/hoisting/expected.js

@@ -5,17 +5,19 @@ var _didIteratorError = false;
 var _iteratorError = undefined;
 
 try {
+  var _loop = function () {
+    var i = _step.value;
+    x = 5;
+
+    fns.push(function () {
+      return i * x;
+    });
+  };
+
   for (var _iterator = nums[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
     var x;
 
-    (function () {
-      var i = _step.value;
-      x = 5;
-
-      fns.push(function () {
-        return i * x;
-      });
-    })();
+    _loop();
   }
 } catch (err) {
   _didIteratorError = true;
@@ -30,4 +32,4 @@ try {
       throw _iteratorError;
     }
   }
-}
+}

test/core/fixtures/transformation/es6.block-scoping/issue-973/actual.js

@@ -0,0 +1,6 @@
+let arr = [];
+for(let i = 0; i < 10; i++) {
+  for (let i = 0; i < 10; i++) {
+    arr.push(() => i);
+  }
+}

test/core/fixtures/transformation/es6.block-scoping/issue-973/expected.js

@@ -0,0 +1,14 @@
+"use strict";
+
+var arr = [];
+for (var i = 0; i < 10; i++) {
+  var _loop = function (_i) {
+    arr.push(function () {
+      return _i;
+    });
+  };
+
+  for (var _i = 0; _i < 10; _i++) {
+    _loop(_i);
+  }
+}

test/core/fixtures/transformation/es6.block-scoping/wrap-closure-shadow-variables/expected.js

@@ -1,11 +1,14 @@
 "use strict";
 
 var a = 1;
+
+var _loop = function (_a) {
+  items.forEach(function (item) {
+    return _a;
+  });
+};
+
 for (var _a = 1; _a < 100; _a++) {
-  (function (_a) {
-    items.forEach(function (item) {
-      return _a;
-    });
-  })(_a);
+  _loop(_a);
 }
-console.log(a);
+console.log(a);

test/core/fixtures/transformation/es6.modules-amd/exports-from/expected.js

@@ -11,11 +11,46 @@ define(["exports", "foo"], function (exports, _foo) {
 
   _defaults(exports, _interopRequireWildcard(_foo));
 
-  exports.foo = _foo.foo;
-  exports.foo = _foo.foo;
-  exports.bar = _foo.bar;
-  exports.bar = _foo.foo;
-  exports["default"] = _foo.foo;
-  exports["default"] = _foo.foo;
-  exports.bar = _foo.bar;
-});
+  Object.defineProperty(exports, "foo", {
+    enumerable: true,
+    get: function get() {
+      return _foo.foo;
+    }
+  });
+  Object.defineProperty(exports, "foo", {
+    enumerable: true,
+    get: function get() {
+      return _foo.foo;
+    }
+  });
+  Object.defineProperty(exports, "bar", {
+    enumerable: true,
+    get: function get() {
+      return _foo.bar;
+    }
+  });
+  Object.defineProperty(exports, "bar", {
+    enumerable: true,
+    get: function get() {
+      return _foo.foo;
+    }
+  });
+  Object.defineProperty(exports, "default", {
+    enumerable: true,
+    get: function get() {
+      return _foo.foo;
+    }
+  });
+  Object.defineProperty(exports, "default", {
+    enumerable: true,
+    get: function get() {
+      return _foo.foo;
+    }
+  });
+  Object.defineProperty(exports, "bar", {
+    enumerable: true,
+    get: function get() {
+      return _foo.bar;
+    }
+  });
+});

test/core/fixtures/transformation/es6.modules-amd/exports-variable/expected.js

@@ -3,10 +3,10 @@ define(["exports"], function (exports) {
 
   var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
 
-  exports.foo7 = foo7;
   Object.defineProperty(exports, "__esModule", {
     value: true
   });
+  exports.foo7 = foo7;
   var foo = 1;
   exports.foo = foo;
   var foo = 1,

test/core/fixtures/transformation/es6.modules-amd/hoist-function-exports/expected.js

@@ -1,20 +1,19 @@
 define(["exports", "./evens"], function (exports, _evens) {
   "use strict";
 
-  exports.nextOdd = nextOdd;
   Object.defineProperty(exports, "__esModule", {
     value: true
   });
-  var isEven = _evens.isEven;
+  exports.nextOdd = nextOdd;
 
   function nextOdd(n) {
-    return isEven(n) ? n + 1 : n + 2;
+    return _evens.isEven(n) ? n + 1 : n + 2;
   }
 
   var isOdd = (function (isEven) {
     return function (n) {
       return !isEven(n);
     };
-  })(isEven);
+  })(_evens.isEven);
   exports.isOdd = isOdd;
-});
+});

test/core/fixtures/transformation/es6.modules-amd/imports-default/actual.js

@@ -1,2 +1,5 @@
 import foo from "foo";
 import {default as foo2} from "foo";
+
+foo;
+foo2;

test/core/fixtures/transformation/es6.modules-amd/imports-default/expected.js

@@ -3,7 +3,10 @@ define(["exports", "foo"], function (exports, _foo) {
 
   var _interopRequire = function (obj) { return obj && obj.__esModule ? obj["default"] : obj; };
 
-  var foo = _interopRequire(_foo);
+  var _foo2 = _interopRequire(_foo);
 
-  var foo2 = _interopRequire(_foo);
-});
+  var _foo22 = _interopRequire(_foo);
+
+  _foo2;
+  _foo22;
+});

test/core/fixtures/transformation/es6.modules-amd/imports-glob/actual.js

@@ -1 +1,3 @@
 import * as foo from "foo";
+
+foo;