diff --git a/bin/babel/index.js b/bin/babel/index.js
index da34ba6fe2..99ab67d1f7 100755
--- a/bin/babel/index.js
+++ b/bin/babel/index.js
@@ -2,32 +2,38 @@
 
 var commander = require("commander");
 var transform = require("../../lib/babel/transformation");
+var kebabCase = require("lodash/string/kebabCase");
+var File      = require("../../lib/babel/transformation/file");
 var util      = require("../../lib/babel/util");
-var fs        = require("fs");
 var each      = require("lodash/collection/each");
 var keys      = require("lodash/object/keys");
+var fs        = require("fs");
+
+each(File.options, function (option, key) {
+  if (option.hidden) return;
+
+  var arg = kebabCase(key);
+
+  if (option.type !== "boolean") {
+    arg += ` [${option.type || "string"}]`;
+  }
+
+  if (option.type === "boolean" && option.default === true) {
+    arg = `no-${key}`;
+  }
+
+  arg = `--${arg}`;
+
+  if (option.shorthand) {
+    arg = `-${option.shorthand}, ${arg}`;
+  }
+
+  commander.option(arg, option.description);
+})
 
-commander.option("-t, --source-maps-inline", "Append sourceMappingURL comment to bottom of code");
-commander.option("-s, --source-maps", "Save source map alongside the compiled code");
-commander.option("-f, --filename [filename]", "Filename to use when reading from stdin - this will be used in source-maps, errors etc [stdin]", "stdin");
 commander.option("-w, --watch", "Recompile files on changes");
-commander.option("-r, --external-helpers", "Replace helpers with references to a `babelHelpers` global");
-commander.option("-e, --experimental", "Enable experimental support for proposed ES7 features");
-commander.option("-p, --playground", "Enable playground support");
-
-commander.option("-c, --compact [mode]", "When set to \"auto\" compact is `true` when the input size exceeds 100KB. (auto|true|false)", "auto");
-commander.option("-m, --modules [modules]", "Module formatter type to use [common]", "common");
-commander.option("-l, --whitelist [whitelist]", "Whitelist of transformers to ONLY use", util.list);
-commander.option("-b, --blacklist [blacklist]", "Blacklist of transformers to NOT use", util.list);
-commander.option("-i, --optional [list]", "List of optional transformers to enable", util.list);
-commander.option("-L, --loose [list]", "List of transformers to enable loose mode ON", util.list);
 commander.option("-o, --out-file [out]", "Compile all input files into a single file");
 commander.option("-d, --out-dir [out]", "Compile an input directory of modules into an output directory");
-commander.option("-c, --remove-comments", "Remove comments from the compiled code", false);
-commander.option("-M, --module-ids", "Insert module id in modules", false);
-commander.option("-R, --react-compat", "Makes the react transformer produce pre-v0.12 code");
-commander.option("--keep-module-id-extensions", "Keep extensions when generating module ids", false);
-commander.option("-a, --auxiliary-comment [comment]", "Comment text to prepend to all auxiliary code");
 commander.option("-D, --copy-files", "When compiling a directory copy over non-compilable files");
 
 commander.on("--help", function () {
@@ -38,9 +44,7 @@ commander.on("--help", function () {
     each(keys(obj).sort(), function (key) {
       if (key[0] === "_") return;
 
-      if (obj[key].optional) {
-        key = "[" + key + "]";
-      }
+      if (obj[key].optional) key = `[${key}]`;
 
       console.log("    - " + key);
     });
@@ -100,24 +104,11 @@ if (errors.length) {
 
 //
 
-exports.opts = {
-  keepModuleIdExtensions: commander.keepModuleIdExtensions,
-  auxiliaryComment:       commander.auxiliaryComment,
-  externalHelpers:        commander.externalHelpers,
-  sourceMapName:          commander.outFile,
-  experimental:           commander.experimental,
-  reactCompat:            commander.reactCompat,
-  playground:             commander.playground,
-  moduleIds:              commander.moduleIds,
-  blacklist:              commander.blacklist,
-  whitelist:              commander.whitelist,
-  sourceMap:              commander.sourceMaps || commander.sourceMapsInline,
-  optional:               commander.optional,
-  comments:               !commander.removeComments,
-  modules:                commander.modules,
-  compact:                commander.compact,
-  loose:                  commander.loose
-};
+exports.opts = {};
+
+each(File.options, function (opt, key) {
+  exports.opts[key] = commander[key];
+});
 
 var fn;
 
diff --git a/bin/babel/util.js b/bin/babel/util.js
index 49c43de4e8..b353e153a8 100644
--- a/bin/babel/util.js
+++ b/bin/babel/util.js
@@ -1,11 +1,10 @@
-var resolveRc = require("../../lib/babel/api/register/resolve-rc");
-var readdir   = require("fs-readdir-recursive");
-var index     = require("./index");
-var babel     = require("../../lib/babel/api/node");
-var util      = require("../../lib/babel/util");
-var path      = require("path");
-var fs        = require("fs");
-var _         = require("lodash");
+var readdir = require("fs-readdir-recursive");
+var index   = require("./index");
+var babel   = require("../../lib/babel/api/node");
+var util    = require("../../lib/babel/util");
+var path    = require("path");
+var fs      = require("fs");
+var _       = require("lodash");
 
 exports.readdirFilter = function (filename) {
   return readdir(filename).filter(function (filename) {
@@ -24,7 +23,6 @@ exports.addSourceMappingUrl = function (code, loc) {
 exports.transform = function (filename, code, opts) {
   opts = _.defaults(opts || {}, index.opts);
   opts.filename = filename;
-  resolveRc(filename, opts);
 
   var result = babel.transform(code, opts);
   result.filename = filename;
diff --git a/package.json b/package.json
index 086793830b..a21f8e800b 100644
--- a/package.json
+++ b/package.json
@@ -54,6 +54,7 @@
     "leven": "^1.0.1",
     "line-numbers": "0.2.0",
     "lodash": "^3.2.0",
+    "minimatch": "^2.0.3",
     "output-file-sync": "^1.1.0",
     "path-is-absolute": "^1.0.0",
     "private": "^0.1.6",
diff --git a/src/babel/api/node.js b/src/babel/api/node.js
index df49f9e21d..fa2a7a7818 100644
--- a/src/babel/api/node.js
+++ b/src/babel/api/node.js
@@ -1,12 +1,13 @@
 import isFunction from "lodash/lang/isFunction";
 import transform from "../transformation";
+import * as util from "../util";
 import fs from "fs";
 
-import * as util from "../util";
-export { util as _util };
+export { util };
 export { canCompile } from "../util";
 
 export { default as acorn } from "acorn-babel";
+export { default as Transformer } from "../transformation/transformer";
 export { default as transform } from "../transformation";
 export { default as traverse } from "../traversal";
 export { default as buildExternalHelpers } from "../tools/build-external-helpers";
@@ -15,7 +16,7 @@ export { version } from "../../../package";
 import * as t from "../types";
 export { t as types };
 
-export function register(opts) {
+export function register(opts?: Object) {
   var callback = require("./register/node");
   if (opts != null) callback(opts);
   return callback;
@@ -25,7 +26,7 @@ export function polyfill() {
   require("../polyfill");
 }
 
-export function transformFile(filename, opts, callback) {
+export function transformFile(filename: string, opts?: Object, callback: Function) {
   if (isFunction(opts)) {
     callback = opts;
     opts = {};
@@ -48,7 +49,7 @@ export function transformFile(filename, opts, callback) {
   });
 }
 
-export function transformFileSync(filename, opts = {}) {
+export function transformFileSync(filename: string, opts?: Object = {}) {
   opts.filename = filename;
   return transform(fs.readFileSync(filename), opts);
 }
diff --git a/src/babel/api/register/cache.js b/src/babel/api/register/cache.js
index 6f7bc54029..dd724ac74a 100644
--- a/src/babel/api/register/cache.js
+++ b/src/babel/api/register/cache.js
@@ -2,7 +2,7 @@ import path from "path";
 import os from "os";
 import fs from "fs";
 
-var FILENAME = process.env.BABEL_CACHE_PATH || path.join(os.tmpdir(), "babel.json");
+const FILENAME = process.env.BABEL_CACHE_PATH || path.join(os.tmpdir(), "babel.json");
 var data = {};
 
 export function save() {
diff --git a/src/babel/api/register/node.js b/src/babel/api/register/node.js
index f2c044af0c..beb06ebdb0 100644
--- a/src/babel/api/register/node.js
+++ b/src/babel/api/register/node.js
@@ -1,7 +1,7 @@
 import "../../polyfill";
 import sourceMapSupport from "source-map-support";
 import * as registerCache from "./cache";
-import resolveRc from "./resolve-rc";
+import resolveRc from "../../tools/resolve-rc";
 import extend from "lodash/object/extend";
 import * as babel from "../node";
 import each from "lodash/collection/each";
@@ -44,6 +44,9 @@ var compile = function (filename) {
   var result;
 
   var opts = extend({}, transformOpts);
+
+  // this will be done when the file is transformed anyway but we need all
+  // the options so we can generate the cache key
   resolveRc(filename, opts);
 
   var cacheKey = `${filename}:${JSON.stringify(opts)}:${babel.version}`;
diff --git a/src/babel/generation/generators/modules.js b/src/babel/generation/generators/modules.js
index b7241adb3a..2218e90486 100644
--- a/src/babel/generation/generators/modules.js
+++ b/src/babel/generation/generators/modules.js
@@ -66,8 +66,10 @@ export function ImportDeclaration(node, print) {
   if (specfiers && specfiers.length) {
     var foundImportSpecifier = false;
 
-    each(node.specifiers, (spec, i) => {
-      if (+i > 0) {
+    for (var i = 0; i < node.specifiers.length; i++) {
+      var spec = node.specifiers[i];
+
+      if (i > 0) {
         this.push(", ");
       }
 
@@ -79,7 +81,7 @@ export function ImportDeclaration(node, print) {
       }
 
       print(spec);
-    });
+    }
 
     if (foundImportSpecifier) {
       this.push(" }");
diff --git a/src/babel/generation/node/parentheses.js b/src/babel/generation/node/parentheses.js
index e429dca474..d3b4302f2d 100644
--- a/src/babel/generation/node/parentheses.js
+++ b/src/babel/generation/node/parentheses.js
@@ -1,7 +1,7 @@
 import each from "lodash/collection/each";
 import * as t from "../../types";
 
-var PRECEDENCE = {};
+const PRECEDENCE = {};
 
 each([
   ["||"],
diff --git a/src/babel/helpers/code-frame.js b/src/babel/helpers/code-frame.js
index e1bb415681..8f24c61502 100644
--- a/src/babel/helpers/code-frame.js
+++ b/src/babel/helpers/code-frame.js
@@ -55,10 +55,10 @@ var highlight = function (text) {
   });
 };
 
-export default function (lines, lineNumber, colNumber) {
+export default function (lines: number, lineNumber: number, colNumber: number, color?): string {
   colNumber = Math.max(colNumber, 0);
 
-  if (chalk.supportsColor) {
+  if (color && chalk.supportsColor) {
     lines = highlight(lines);
   }
 
diff --git a/src/babel/helpers/parse.js b/src/babel/helpers/parse.js
index b93361c638..124407c96f 100644
--- a/src/babel/helpers/parse.js
+++ b/src/babel/helpers/parse.js
@@ -32,12 +32,12 @@ export default function (opts, code, callback) {
   } catch (err) {
     if (!err._babel) {
       err._babel = true;
+
       var message = `${opts.filename}: ${err.message}`;
 
       var loc = err.loc;
       if (loc) {
-        var frame = codeFrame(code, loc.line, loc.column + 1);
-        message += frame;
+        message += codeFrame(code, loc.line, loc.column + 1, opts.highlightErrors);
       }
 
       if (err.stack) {
diff --git a/src/babel/messages.js b/src/babel/messages.js
index f97e84c969..6a4952dcf3 100644
--- a/src/babel/messages.js
+++ b/src/babel/messages.js
@@ -1,6 +1,6 @@
 import * as util from  "util";
 
-export var messages = {
+export const MESSAGES = {
   tailCallReassignmentDeopt: "Function reference has been reassigned so it's probably be dereferenced so we can't optimise this with confidence",
   JSXNamespacedTags: "Namespace tags are not supported. ReactJSX is not XML.",
   classesIllegalBareSuper: "Illegal use of bare super",
@@ -25,7 +25,7 @@ export var messages = {
 };
 
 export function get(key: String, ...args) {
-  var msg = messages[key];
+  var msg = MESSAGES[key];
   if (!msg) throw new ReferenceError(`Unknown message ${JSON.stringify(key)}`);
 
   args = parseArgs(args);
diff --git a/src/babel/api/register/resolve-rc.js b/src/babel/tools/resolve-rc.js
similarity index 100%
rename from src/babel/api/register/resolve-rc.js
rename to src/babel/tools/resolve-rc.js
diff --git a/src/babel/transformation/file.js b/src/babel/transformation/file/index.js
similarity index 74%
rename from src/babel/transformation/file.js
rename to src/babel/transformation/file/index.js
index ee40919b2f..22559262c1 100644
--- a/src/babel/transformation/file.js
+++ b/src/babel/transformation/file/index.js
@@ -1,20 +1,25 @@
 import convertSourceMap from "convert-source-map";
+import * as optionParsers from "./option-parsers";
 import shebangRegex from "shebang-regex";
+import TraversalPath from "../../traversal/path";
 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 transform from "./../index";
+import generate from "../../generation";
 import defaults from "lodash/object/defaults";
 import includes from "lodash/collection/includes";
+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 parse from "../../helpers/parse";
+import Scope from "../../traversal/scope";
 import slash from "slash";
-import * as util from  "../util";
+import * as util from  "../../util";
 import path from "path";
 import each from "lodash/collection/each";
-import * as t from "../types";
+import * as t from "../../types";
 
 var checkTransformerVisitor = {
   enter(node, parent, scope, state) {
@@ -78,84 +83,37 @@ export default class File {
     "self-global"
   ];
 
-  static validOptions = [
-    "filename",
-    "filenameRelative",
-
-    "blacklist",
-    "whitelist",
-    "optional",
-
-    "loose",
-    "playground",
-    "experimental",
-
-    "modules",
-    "moduleIds",
-    "moduleId",
-    "resolveModuleSource",
-    "keepModuleIdExtensions",
-
-    "code",
-    "ast",
-
-    "comments",
-    "compact",
-
-    "auxiliaryComment",
-    "externalHelpers",
-    "returnUsedHelpers",
-
-    "inputSourceMap",
-    "sourceMap",
-    "sourceMapName",
-    "sourceFileName",
-    "sourceRoot",
-    "moduleRoot",
-
-    // legacy
-    "format",
-    "reactCompat",
-
-    // these are used by plugins
-    "ignore",
-    "only",
-    "extensions",
-    "accept"
-  ];
+  static options = require("./options");
 
   normalizeOptions(opts: Object) {
     opts = assign({}, opts);
 
-    for (var key in opts) {
-      if (key[0] !== "_" && File.validOptions.indexOf(key) < 0) {
-        throw new ReferenceError(`Unknown option: ${key}`);
-      }
+    if (opts.filename && isAbsolute(opts.filename)) {
+      opts = resolveRc(opts.filename, opts);
     }
 
-    defaults(opts, {
-      keepModuleIdExtensions: false,
-      resolveModuleSource:    null,
-      returnUsedHelpers:      false,
-      externalHelpers:        false,
-      auxilaryComment:        "",
-      inputSourceMap:         null,
-      experimental:           false,
-      reactCompat:            false,
-      playground:             false,
-      moduleIds:              false,
-      blacklist:              [],
-      whitelist:              [],
-      sourceMap:              false,
-      optional:               [],
-      comments:               true,
-      filename:               "unknown",
-      modules:                "common",
-      compact:                "auto",
-      loose:                  [],
-      code:                   true,
-      ast:                    true
-    });
+    //
+
+    for (let key in opts) {
+      if (key[0] === "_") continue;
+
+      let option = File.options[key];
+      if (!option) throw new ReferenceError(`Unknown option: ${key}`);
+    }
+
+    for (let key in File.options) {
+      let option = File.options[key];
+
+      var val = opts[key];
+      if (val == null) val = option.default || null;
+
+      var optionParser = optionParsers[option.type];
+      if (optionParser) {
+        val = optionParser(key, val);
+      }
+
+      opts[key] = val;
+    }
 
     if (opts.inputSourceMap) {
       opts.sourceMap = true;
@@ -173,15 +131,8 @@ export default class File {
 
     opts.basename = path.basename(opts.filename, path.extname(opts.filename));
 
-    opts.blacklist = util.arrayify(opts.blacklist);
-    opts.whitelist = util.arrayify(opts.whitelist);
-    opts.optional  = util.arrayify(opts.optional);
-    opts.compact   = util.booleanify(opts.compact);
-    opts.loose     = util.arrayify(opts.loose);
-
-    if (includes(opts.loose, "all") || includes(opts.loose, true)) {
-      opts.loose = Object.keys(transform.transformers);
-    }
+    opts.ignore   = util.arrayify(opts.ignore, util.regexify);
+    opts.only     = util.arrayify(opts.only, util.regexify);
 
     defaults(opts, {
       moduleRoot: opts.sourceRoot
@@ -200,33 +151,12 @@ export default class File {
       sourceMapName:  opts.filenameRelative
     });
 
-    if (opts.playground) {
-      opts.experimental = true;
-    }
+    //
 
     if (opts.externalHelpers) {
       this.set("helpersNamespace", t.identifier("babelHelpers"));
     }
 
-    opts.blacklist = transform._ensureTransformerNames("blacklist", opts.blacklist);
-    opts.whitelist = transform._ensureTransformerNames("whitelist", opts.whitelist);
-    opts.optional  = transform._ensureTransformerNames("optional", opts.optional);
-    opts.loose     = transform._ensureTransformerNames("loose", opts.loose);
-
-    if (opts.reactCompat) {
-      opts.optional.push("reactCompat");
-      console.error("The reactCompat option has been moved into the optional transformer `reactCompat`");
-    }
-
-    var ensureEnabled = function (key) {
-      var namespace = transform.transformerNamespaces[key];
-      if (namespace === "es7") opts.experimental = true;
-      if (namespace === "playground") opts.playground = true;
-    };
-
-    each(opts.whitelist, ensureEnabled);
-    each(opts.optional, ensureEnabled);
-
     return opts;
   };
 
@@ -234,6 +164,10 @@ export default class File {
     return includes(this.opts.loose, key);
   }
 
+  buildPlugins(stack) {
+
+  }
+
   buildTransformers() {
     var file = this;
 
@@ -242,6 +176,8 @@ export default class File {
     var secondaryStack = [];
     var stack = [];
 
+    this.buildPlugins(stack);
+
     each(transform.transformers, function (transformer, key) {
       var pass = transformers[key] = transformer.buildPass(file);
 
@@ -377,7 +313,7 @@ export default class File {
     this.usedHelpers[name] = true;
 
     var generator = this.get("helperGenerator");
-    var runtime = this.get("helpersNamespace");
+    var runtime   = this.get("helpersNamespace");
     if (generator) {
       return generator(name);
     } else if (runtime) {
@@ -410,7 +346,36 @@ export default class File {
     return this.parseShebang(code);
   }
 
+  shouldIgnore() {
+    var opts = this.opts;
+
+    var filename = opts.filename;
+    var ignore   = opts.ignore;
+    var only     = opts.only;
+
+    if (only.length) {
+      for (var i = 0; i < only.length; i++) {
+        if (only[i].test(filename)) return false;
+      }
+      return true;
+    } else if (ignore.length) {
+      for (var i = 0; i < ignore.length; i++) {
+        if (ignore[i].test(filename)) return true;
+      }
+    }
+
+    return false;
+  }
+
   parse(code: string) {
+    if (this.shouldIgnore()) {
+      return {
+        code: code,
+        map:  null,
+        ast:  null
+      };
+    }
+
     code = this.addCode(code);
 
     var opts = this.opts;
@@ -424,12 +389,28 @@ export default class File {
     });
   }
 
+  setAst(ast) {
+    this.path  = TraversalPath.get(null, null, ast, ast, "program", this);
+    this.scope = this.path.scope;
+    this.ast   = ast;
+
+    this.path.traverse({
+      enter(node, parent, scope) {
+        if (this.isScope()) {
+          for (var key in scope.bindings) {
+            scope.bindings[key].setTypeAnnotation();
+          }
+        }
+      }
+    });
+  }
+
   transform(ast) {
     this.log.debug();
 
-    this.ast = ast;
+    this.setAst(ast);
+
     this.lastStatements = t.getLastStatements(ast.program);
-    this.scope = new Scope(ast.program, ast, null, this);
 
     var modFormatter = this.moduleFormatter = this.getModuleFormatter(this.opts.modules);
     if (modFormatter.init && this.transformers["es6.modules"].canRun()) {
@@ -483,14 +464,14 @@ export default class File {
     if (inputMap) {
       map.sources[0] = inputMap.file;
 
-      var inputMapConsumer = new sourceMap.SourceMapConsumer(inputMap);
-      var outputMapConsumer = new sourceMap.SourceMapConsumer(map);
+      var inputMapConsumer   = new sourceMap.SourceMapConsumer(inputMap);
+      var outputMapConsumer  = new sourceMap.SourceMapConsumer(map);
       var outputMapGenerator = sourceMap.SourceMapGenerator.fromSourceMap(outputMapConsumer);
       outputMapGenerator.applySourceMap(inputMapConsumer);
 
       var mergedMap = outputMapGenerator.toJSON();
       mergedMap.sources = inputMap.sources
-      mergedMap.file = inputMap.file;
+      mergedMap.file    = inputMap.file;
       return mergedMap;
     }
 
@@ -498,6 +479,7 @@ export default class File {
   }
 
   generate(): {
+    usedHelpers?: Array<string>;
     code: string;
     map?: Object;
     ast?: Object;
@@ -507,8 +489,8 @@ export default class File {
 
     var result = {
       code: "",
-      map: null,
-      ast: null
+      map:  null,
+      ast:  null
     };
 
     if (this.opts.returnUsedHelpers) {
diff --git a/src/babel/transformation/logger.js b/src/babel/transformation/file/logger.js
similarity index 74%
rename from src/babel/transformation/logger.js
rename to src/babel/transformation/file/logger.js
index 29e185af9d..109019c810 100644
--- a/src/babel/transformation/logger.js
+++ b/src/babel/transformation/file/logger.js
@@ -1,4 +1,4 @@
-import * as util from  "../util";
+import * as util from  "../../util";
 
 export default class Logger {
   constructor(file: File) {
@@ -12,6 +12,12 @@ export default class Logger {
     return parts;
   }
 
+  deprecate(msg) {
+    if (!file.opts.suppressDeprecationMessages) {
+      console.error(msg);
+    }
+  }
+
   debug(msg: string) {
     util.debug(this._buildMessage(msg));
   }
diff --git a/src/babel/transformation/file/option-parsers.js b/src/babel/transformation/file/option-parsers.js
new file mode 100644
index 0000000000..a0a2cc33d2
--- /dev/null
+++ b/src/babel/transformation/file/option-parsers.js
@@ -0,0 +1,20 @@
+import transform from "./../index";
+import * as util from  "../../util";
+
+export function transformerList(key, val) {
+  val = util.arrayify(val);
+
+  if (val.indexOf("all") >= 0 || val.indexOf(true) >= 0) {
+    val = Object.keys(transform.transformers);
+  }
+
+  return transform._ensureTransformerNames(key, val);
+}
+
+export function boolean(key, val) {
+  return util.booleanify(val);
+}
+
+export function list(key, val) {
+  return util.list(val);
+}
diff --git a/src/babel/transformation/file/options.json b/src/babel/transformation/file/options.json
new file mode 100644
index 0000000000..0482ff9576
--- /dev/null
+++ b/src/babel/transformation/file/options.json
@@ -0,0 +1,164 @@
+{
+  "filename": {
+    "type": "string",
+    "description": "Filename to use when reading from stdin - this will be used in source-maps, errors etc",
+    "default": "unknown",
+    "shorthand": "f"
+  },
+
+  "filenameRelative": {
+    "hidden": true,
+    "type": "string"
+  },
+
+  "inputSourceMap": {
+    "hidden": true
+  },
+
+  "moduleId": {
+
+  },
+
+  "highlightErrors": {
+    "description": "ANSI syntax highlight error messages"
+    "type": "boolean",
+    "default": true
+  },
+
+  "suppressDeprecationMessages": {
+    "type": "boolean",
+    "default": false,
+    "hidden": true
+  },
+
+  "resolveModuleSource": {
+    "hidden": true
+  },
+
+  "experimental": {
+    "description": "Enable all ES7+ transformers",
+    "shorthand": "e",
+    "type": "boolean",
+    "default": false
+  },
+
+  "playground": {
+    "description": "Enable all playground transformers",
+    "shorthand": "p",
+    "type": "boolean",
+    "default": false
+  },
+
+  "blacklist": {
+    "type": "transformerList",
+    "description": "Blacklist of transformers to NOT use",
+    "shorthand": "b"
+  },
+
+  "whitelist": {
+    "type": "transformerList",
+    "description": "Whitelist of transformers to ONLY use",
+    "shorthand": "l"
+  },
+
+  "optional": {
+    "type": "transformerList",
+    "description": "List of optional transformers to enable"
+  },
+
+  "modules": {
+    "type": "string",
+    "description": "Module formatter type to use [common]",
+    "default": "common",
+    "shorthand": "m"
+  },
+
+  "moduleIds": {
+    "type": "boolean",
+    "default": false,
+    "shorthand": "M"
+  },
+
+  "loose": {
+    "type": "transformerList",
+    "description": "List of transformers to enable loose mode ON",
+    "shorthand": "L"
+  },
+
+  "ignore": {
+    "type": "list"
+  },
+
+  "only": {
+    "type": "list"
+  },
+
+  "code": {
+    "hidden": true,
+    "default": true,
+    "type": "boolean"
+  },
+
+  "ast": {
+    "hidden": true,
+    "default": true,
+    "type": "boolean"
+  },
+
+  "comments": {
+    "type": "boolean",
+    "default": true
+  },
+
+  "compact": {
+    "type": "string",
+    "default": "auto"
+  },
+
+  "keepModuleIdExtensions": {
+    "type": "boolean",
+    "description": "Keep extensions when generating module ids",
+    "default": false,
+    "shorthand": "k"
+  },
+
+  "auxiliaryComment": {
+    "type": "string",
+    "default": "",
+    "shorthand": "a"
+  },
+
+  "externalHelpers": {
+    "type": "string",
+    "default": false,
+    "shorthand": "r"
+  },
+
+  "returnUsedHelpers": {
+    "type": "boolean",
+    "default": false,
+    "hidden": true
+  },
+
+  "sourceMap": {
+    "type": "string",
+    "default": false,
+    "shorthand": "s"
+  },
+
+  "sourceMapName": {
+    "type": "string"
+  },
+
+  "sourceFileName": {
+    "type": "string"
+  },
+
+  "sourceRoot": {
+    "type": "string"
+  },
+
+  "moduleRoot": {
+    "type": "string"
+  }
+}
diff --git a/src/babel/transformation/helpers/build-react-transformer.js b/src/babel/transformation/helpers/build-react-transformer.js
index 02b9ba1ffe..ccef9d819b 100644
--- a/src/babel/transformation/helpers/build-react-transformer.js
+++ b/src/babel/transformation/helpers/build-react-transformer.js
@@ -27,7 +27,7 @@ export default function (exports, opts) {
   };
 
   exports.JSXNamespacedName = function (node, parent, scope, file) {
-    throw file.errorWithNode(node, messages.get("JSXNamespacedTags"));
+    throw this.errorWithNode(messages.get("JSXNamespacedTags"));
   };
 
   exports.JSXMemberExpression = {
diff --git a/src/babel/transformation/helpers/replace-supers.js b/src/babel/transformation/helpers/replace-supers.js
index e60cbabcb4..aa80001ff6 100644
--- a/src/babel/transformation/helpers/replace-supers.js
+++ b/src/babel/transformation/helpers/replace-supers.js
@@ -39,7 +39,7 @@ var visitor = {
 
     var callback = self.specHandle;
     if (self.isLoose) callback = self.looseHandle;
-    return callback.call(self, getThisReference, node, parent);
+    return callback.call(self, this, getThisReference);
   }
 };
 
@@ -191,11 +191,12 @@ export default class ReplaceSupers {
    * Description
    */
 
-  looseHandle(getThisReference: Function, node: Object, parent: Object) {
-    if (t.isIdentifier(node, { name: "super" })) {
+  looseHandle(path: TraversalPath, getThisReference: Function) {
+    var node = path.node;
+    if (path.isIdentifier({ name: "super" })) {
       this.hasSuper = true;
-      return this.getLooseSuperProperty(node, parent);
-    } else if (t.isCallExpression(node)) {
+      return this.getLooseSuperProperty(node, path.parent);
+    } else if (path.isCallExpression()) {
       var callee = node.callee;
       if (!t.isMemberExpression(callee)) return;
       if (callee.object.name !== "super") return;
@@ -211,15 +212,18 @@ export default class ReplaceSupers {
    * Description
    */
 
-  specHandle(getThisReference: Function, node: Object, parent: Object) {
+  specHandle(path: TraversalPath, getThisReference: Function) {
     var methodNode = this.methodNode;
     var property;
     var computed;
     var args;
     var thisReference;
 
+    var parent = path.parent;
+    var node = path.node;
+
     if (isIllegalBareSuper(node, parent)) {
-      throw this.file.errorWithNode(node, messages.get("classesIllegalBareSuper"));
+      throw path.errorWithNode(messages.get("classesIllegalBareSuper"));
     }
 
     if (t.isCallExpression(node)) {
diff --git a/src/babel/transformation/index.js b/src/babel/transformation/index.js
index 1c02c4ee2a..8d244aa51a 100644
--- a/src/babel/transformation/index.js
+++ b/src/babel/transformation/index.js
@@ -4,7 +4,7 @@ import object from "../helpers/object";
 import File from "./file";
 import each from "lodash/collection/each";
 
-export default function transform(code: code, opts?: Object) {
+export default function transform(code: string, opts?: Object) {
   var file = new File(opts);
   return file.parse(code);
 }
diff --git a/src/babel/transformation/modules/_default.js b/src/babel/transformation/modules/_default.js
index a60d3b7507..2158b8525f 100644
--- a/src/babel/transformation/modules/_default.js
+++ b/src/babel/transformation/modules/_default.js
@@ -45,7 +45,7 @@ var importsVisitor = {
   ImportDeclaration: {
     enter(node, parent, scope, formatter) {
       formatter.hasLocalImports = true;
-      extend(formatter.localImports, t.getBindingIdentifiers(node));
+      extend(formatter.localImports, this.getBindingIdentifiers());
       formatter.bumpImportOccurences(node);
     }
   }
@@ -54,11 +54,11 @@ var importsVisitor = {
 var exportsVisitor = {
   ExportDeclaration: {
     enter(node, parent, scope, formatter) {
-      var declar = node.declaration;
+      var declar = this.get("declaration");
       formatter.hasLocalImports = true;
 
-      if (declar && t.isStatement(declar)) {
-        extend(formatter.localExports, t.getBindingIdentifiers(declar));
+      if (declar.isStatement()) {
+        extend(formatter.localExports, declar.getBindingIdentifiers());
       }
 
       if (!node.default) {
@@ -105,16 +105,16 @@ export default class DefaultFormatter {
   }
 
   getLocalExports() {
-    this.file.scope.traverse(this.file.ast, exportsVisitor, this);
+    this.file.path.traverse(exportsVisitor, this);
   }
 
   getLocalImports() {
-    this.file.scope.traverse(this.file.ast, importsVisitor, this);
+    this.file.path.traverse(importsVisitor, this);
   }
 
   remapAssignments() {
     if (this.hasLocalImports) {
-      this.file.scope.traverse(this.file.ast, remapVisitor, this);
+      this.file.path.traverse(remapVisitor, this);
     }
   }
 
diff --git a/src/babel/transformation/templates/for-of-array.js b/src/babel/transformation/templates/for-of-array.js
new file mode 100644
index 0000000000..7f27900c15
--- /dev/null
+++ b/src/babel/transformation/templates/for-of-array.js
@@ -0,0 +1 @@
+for (var KEY = 0; KEY < ARR.length; KEY++) BODY;
diff --git a/src/babel/transformation/transformer-pass.js b/src/babel/transformation/transformer-pass.js
index 3beac40bc8..0d9897f259 100644
--- a/src/babel/transformation/transformer-pass.js
+++ b/src/babel/transformation/transformer-pass.js
@@ -1,4 +1,5 @@
 import includes from "lodash/collection/includes";
+import traverse from "../traversal";
 
 /**
  * This class is responsible for traversing over the provided `File`s
@@ -31,14 +32,14 @@ export default class TransformerPass {
     var whitelist = opts.whitelist;
     if (whitelist.length) return includes(whitelist, key);
 
-    // optional
-    if (transformer.optional && !includes(opts.optional, key)) return false;
-
     // experimental
-    if (transformer.experimental && !opts.experimental) return false;
+    if (transformer.experimental && opts.experimental) return true;
 
     // playground
-    if (transformer.playground && !opts.playground) return false;
+    if (transformer.playground && opts.playground) return true;
+
+    // optional
+    if (transformer.optional && !includes(opts.optional, key)) return false;
 
     return true;
   }
@@ -59,7 +60,7 @@ export default class TransformerPass {
 
     file.log.debug(`Running transformer ${this.transformer.key}`);
 
-    file.scope.traverse(file.ast, this.handlers, file);
+    traverse(file.ast, this.handlers, file.scope, file);
 
     this.ran = true;
   }
diff --git a/src/babel/transformation/transformer.js b/src/babel/transformation/transformer.js
index fddb3ae2a1..6a05af07c1 100644
--- a/src/babel/transformation/transformer.js
+++ b/src/babel/transformation/transformer.js
@@ -3,6 +3,7 @@ import isFunction from "lodash/lang/isFunction";
 import traverse from "../traversal";
 import isObject from "lodash/lang/isObject";
 import assign from "lodash/object/assign";
+import File from "./file";
 import each from "lodash/collection/each";
 
 /**
@@ -66,6 +67,10 @@ export default class Transformer {
   }
 
   buildPass(file: File): TransformerPass {
+    if (!(file instanceof File)) {
+      throw new Error("Multiple versions of babel are interacting, this is either due to a version mismatch in a plugin or it was resolved incorrectly");
+    }
+
     return new TransformerPass(file, this);
   }
 }
diff --git a/src/babel/transformation/transformers/es6/block-scoping-tdz.js b/src/babel/transformation/transformers/es6/block-scoping-tdz.js
index d18333a192..0eee6bc324 100644
--- a/src/babel/transformation/transformers/es6/block-scoping-tdz.js
+++ b/src/babel/transformation/transformers/es6/block-scoping-tdz.js
@@ -32,7 +32,7 @@ export function BlockStatement(node, parent, scope, file) {
   var letRefs = node._letReferences;
   if (!letRefs) return;
 
-  scope.traverse(node, visitor, {
+  this.traverse(visitor, {
     letRefs: letRefs,
     file:    file
   });
diff --git a/src/babel/transformation/transformers/es6/block-scoping.js b/src/babel/transformation/transformers/es6/block-scoping.js
index 79eb0380c7..ee7e87402f 100644
--- a/src/babel/transformation/transformers/es6/block-scoping.js
+++ b/src/babel/transformation/transformers/es6/block-scoping.js
@@ -111,7 +111,7 @@ function traverseReplace(node, parent, scope, remaps) {
 var letReferenceBlockVisitor = {
   enter(node, parent, scope, state) {
     if (this.isFunction()) {
-      scope.traverse(node, letReferenceFunctionVisitor, state);
+      this.traverse(letReferenceFunctionVisitor, state);
       return this.skip();
     }
   }
@@ -173,7 +173,7 @@ var loopVisitor = {
 
     if (this.isLoop()) {
       state.ignoreLabeless = true;
-      scope.traverse(node, loopVisitor, state);
+      this.traverse(loopVisitor, state);
       state.ignoreLabeless = false;
     }
 
diff --git a/src/babel/transformation/transformers/es6/classes.js b/src/babel/transformation/transformers/es6/classes.js
index f0ccc38c5f..add480ac59 100644
--- a/src/babel/transformation/transformers/es6/classes.js
+++ b/src/babel/transformation/transformers/es6/classes.js
@@ -15,7 +15,7 @@ export function ClassDeclaration(node, parent, scope, file) {
 }
 
 export function ClassExpression(node, parent, scope, file) {
-  return new ClassTransformer(node, parent, scope, file).run();
+  return new ClassTransformer(this, file).run();
 }
 
 var verifyConstructorVisitor = traverse.explode({
@@ -33,11 +33,11 @@ var verifyConstructorVisitor = traverse.explode({
 
   CallExpression: {
     enter(node, parent, scope, state) {
-      if (t.isIdentifier(node.callee, { name: "super" })) {
+      if (this.get("callee").isIdentifier({ name: "super" })) {
         state.hasBareSuper = true;
 
         if (!state.hasSuper) {
-          throw state.file.errorWithNode(node, "super call is only allowed in derived constructor");
+          throw this.errorWithNode("super call is only allowed in derived constructor");
         }
       }
     }
@@ -46,7 +46,7 @@ var verifyConstructorVisitor = traverse.explode({
   ThisExpression: {
     enter(node, parent, scope, state) {
       if (state.hasSuper && !state.hasBareSuper) {
-        throw state.file.errorWithNode(node, "'this' is not allowed before super()");
+        throw this.errorWithNode("'this' is not allowed before super()");
       }
     }
   }
@@ -58,10 +58,11 @@ class ClassTransformer {
    * Description
    */
 
-  constructor(node: Object, parent: Object, scope: Scope, file: File) {
-    this.parent = parent;
-    this.scope  = scope;
-    this.node   = node;
+  constructor(path: TraversalPath, file: File) {
+    this.parent = path.parent;
+    this.scope  = path.scope;
+    this.node   = path.node;
+    this.path   = path;
     this.file   = file;
 
     this.hasInstanceMutators = false;
@@ -71,11 +72,11 @@ class ClassTransformer {
     this.staticMutatorMap   = {};
 
     this.hasConstructor = false;
-    this.className      = node.id;
-    this.classRef       = node.id || scope.generateUidIdentifier("class");
+    this.className      = this.node.id;
+    this.classRef       = this.node.id || this.scope.generateUidIdentifier("class");
 
-    this.superName = node.superClass || t.identifier("Function");
-    this.hasSuper  = !!node.superClass;
+    this.superName = this.node.superClass || t.identifier("Function");
+    this.hasSuper  = !!this.node.superClass;
 
     this.isLoose = file.isLoose("es6.classes");
   }
@@ -174,11 +175,13 @@ class ClassTransformer {
     var classBody   = this.node.body.body;
     var body        = this.body;
 
+    var classBodyPaths = this.path.get("body").get("body");
+
     for (var i = 0; i < classBody.length; i++) {
       var node = classBody[i];
       if (t.isMethodDefinition(node)) {
         var isConstructor = (!node.computed && t.isIdentifier(node.key, { name: "constructor" })) || t.isLiteral(node.key, { value: "constructor" });
-        if (isConstructor) this.verifyConstructor(node);
+        if (isConstructor) this.verifyConstructor(classBodyPaths[i]);
 
         var replaceSupers = new ReplaceSupers({
           methodNode: node,
@@ -205,8 +208,8 @@ class ClassTransformer {
       }
     }
 
-    // we have no constructor, we have a super, and the super doesn't appear to be falsy
-    if (!this.hasConstructor && this.hasSuper && t.evaluateTruthy(superName, this.scope) !== false) {
+    // we have no constructor, but we're a derived class
+    if (!this.hasConstructor && this.hasSuper) {
       var helperName = "class-super-constructor-call";
       if (this.isLoose) helperName += "-loose";
       constructor.body.body.push(util.template(helperName, {
@@ -249,19 +252,17 @@ class ClassTransformer {
    * Description
    */
 
-   verifyConstructor(node: Object) {
-    return; // enable this for the next major
-
+   verifyConstructor(path: TraversalPath) {
     var state = {
       hasBareSuper: false,
       hasSuper:     this.hasSuper,
       file:         this.file
     };
 
-    traverse(node, verifyConstructorVisitor, this.scope, state);
+    path.traverse(verifyConstructorVisitor, state);
 
     if (!state.hasBareSuper && this.hasSuper) {
-      throw this.file.errorWithNode(node, "Derived constructor must call super()");
+      throw path.errorWithNode("Derived constructor must call super()");
     }
    }
 
diff --git a/src/babel/transformation/transformers/es6/constants.js b/src/babel/transformation/transformers/es6/constants.js
index fc29e8c916..4a4e5c95d2 100644
--- a/src/babel/transformation/transformers/es6/constants.js
+++ b/src/babel/transformation/transformers/es6/constants.js
@@ -37,7 +37,7 @@ var visitor = {
 };
 
 export function Scopable(node, parent, scope, file) {
-  scope.traverse(node, visitor, {
+  this.traverse(visitor, {
     constants: scope.getAllBindingsOfKind("const"),
     file:      file
   });
diff --git a/src/babel/transformation/transformers/es6/destructuring.js b/src/babel/transformation/transformers/es6/destructuring.js
index ea9e3bdaf3..a27e70c907 100644
--- a/src/babel/transformation/transformers/es6/destructuring.js
+++ b/src/babel/transformation/transformers/es6/destructuring.js
@@ -432,7 +432,7 @@ class DestructuringTransformer {
     } else {
       arrayRef = this.scope.generateUidBasedOnNode(arrayRef);
       this.nodes.push(this.buildVariableDeclaration(arrayRef, toArray));
-      this.scope.assignTypeGeneric(arrayRef.name, "Array");
+      //this.getBinding(arrayRef.name).assignTypeGeneric("Array");
     }
 
     //
diff --git a/src/babel/transformation/transformers/es6/for-of.js b/src/babel/transformation/transformers/es6/for-of.js
index 7c6674ab2d..5d6e380dc0 100644
--- a/src/babel/transformation/transformers/es6/for-of.js
+++ b/src/babel/transformation/transformers/es6/for-of.js
@@ -5,6 +5,10 @@ import * as t from "../../../types";
 export var check = t.isForOfStatement;
 
 export function ForOfStatement(node, parent, scope, file) {
+  if (this.get("right").isArrayExpression()) {
+    return _ForOfStatementArray.call(this, node, scope, file);
+  }
+
   var callback = spec;
   if (file.isLoose("es6.forOf")) callback = loose;
 
@@ -29,13 +33,48 @@ export function ForOfStatement(node, parent, scope, file) {
 
   t.inherits(loop, node);
 
-  // todo: find out why this is necessary? #538
-  loop._scopeInfo = node._scopeInfo;
-
   if (build.replaceParent) this.parentPath.node = build.node;
   return build.node;
 }
 
+export function _ForOfStatementArray(node, scope, file) {
+  var nodes = [];
+  var right = node.right;
+
+  if (!t.isIdentifier(right) || !scope.hasBinding(right.name)) {
+    var uid = scope.generateUidIdentifier("arr");
+    nodes.push(t.variableDeclaration("var", [
+      t.variableDeclarator(uid, right)
+    ]));
+    right = uid;
+  }
+
+  var iterationKey = scope.generateUidIdentifier("i");
+
+  var loop = util.template("for-of-array", {
+    BODY: node.body,
+    KEY:  iterationKey,
+    ARR:  right
+  });
+
+  t.inherits(loop, node);
+  t.ensureBlock(loop);
+
+  var iterationValue = t.memberExpression(right, iterationKey, true);
+
+  var left = node.left;
+  if (t.isVariableDeclaration(left)) {
+    left.declarations[0].init = iterationValue;
+    loop.body.body.unshift(left);
+  } else {
+    loop.body.body.unshift(t.expressionStatement(t.assignmentExpression("=", left, iterationValue)));
+  }
+
+  nodes.push(loop);
+
+  return nodes;
+}
+
 var loose = function (node, parent, scope, file) {
   var left = node.left;
   var declar, id;
diff --git a/src/babel/transformation/transformers/es6/modules.js b/src/babel/transformation/transformers/es6/modules.js
index 0eab992dfe..cb583622d6 100644
--- a/src/babel/transformation/transformers/es6/modules.js
+++ b/src/babel/transformation/transformers/es6/modules.js
@@ -26,7 +26,7 @@ export function ImportDeclaration(node, parent, scope, file) {
 
 export function ExportDeclaration(node, parent, scope, file) {
   // flow type
-  if (t.isTypeAlias(node.declaration)) return;
+  if (this.get("declaration").isTypeAlias()) return;
 
   var nodes = [];
   var i;
diff --git a/src/babel/transformation/transformers/es6/parameters.default.js b/src/babel/transformation/transformers/es6/parameters.default.js
index 9e525c87d3..82dd26e20e 100644
--- a/src/babel/transformation/transformers/es6/parameters.default.js
+++ b/src/babel/transformation/transformers/es6/parameters.default.js
@@ -49,41 +49,42 @@ exports.Function = function (node, parent, scope, file) {
     body.push(defNode);
   };
 
-  for (var i = 0; i < node.params.length; i++) {
-    var param = node.params[i];
+  var params = this.get("params");
+  for (var i = 0; i < params.length; i++) {
+    var param = params[i];
 
-    if (!t.isAssignmentPattern(param)) {
-      if (!t.isRestElement(param)) {
+    if (!param.isAssignmentPattern()) {
+      if (!param.isRestElement()) {
         lastNonDefaultParam = i + 1;
       }
 
-      if (!t.isIdentifier(param)) {
-        scope.traverse(param, iifeVisitor, state);
+      if (!param.isIdentifier()) {
+        param.traverse(iifeVisitor, state);
       }
 
-      if (file.transformers["es6.blockScopingTDZ"].canRun() && t.isIdentifier(param)) {
-        pushDefNode(param, t.identifier("undefined"), i);
+      if (file.transformers["es6.blockScopingTDZ"].canRun() && param.isIdentifier()) {
+        pushDefNode(param.node, t.identifier("undefined"), i);
       }
 
       continue;
     }
 
-    var left  = param.left;
-    var right = param.right;
+    var left  = param.get("left");
+    var right = param.get("right");
 
     var placeholder = scope.generateUidIdentifier("x");
     placeholder._isDefaultPlaceholder = true;
     node.params[i] = placeholder;
 
     if (!state.iife) {
-      if (t.isIdentifier(right) && scope.hasOwnBinding(right.name)) {
+      if (right.isIdentifier() && scope.hasOwnBinding(right.node.name)) {
         state.iife = true;
       } else {
-        scope.traverse(right, iifeVisitor, state);
+        right.traverse(iifeVisitor, state);
       }
     }
 
-    pushDefNode(left, right, i);
+    pushDefNode(left.node, right.node, i);
   }
 
   // we need to cut off all trailing default parameters
diff --git a/src/babel/transformation/transformers/es6/parameters.rest.js b/src/babel/transformation/transformers/es6/parameters.rest.js
index 14098fa0e3..d0f967a8f7 100644
--- a/src/babel/transformation/transformers/es6/parameters.rest.js
+++ b/src/babel/transformation/transformers/es6/parameters.rest.js
@@ -15,7 +15,7 @@ var memberExpressionOptimisationVisitor = {
     // to the wrong function
     if (this.isFunctionDeclaration() || this.isFunctionExpression()) {
       state.noOptimise = true;
-      scope.traverse(node, memberExpressionOptimisationVisitor, state);
+      this.traverse(memberExpressionOptimisationVisitor, state);
       state.noOptimise = false;
       return this.skip();
     }
@@ -88,7 +88,7 @@ exports.Function = function (node, parent, scope, file) {
     name:         rest.name
   };
 
-  scope.traverse(node, memberExpressionOptimisationVisitor, state);
+  this.traverse(memberExpressionOptimisationVisitor, state);
 
   // we only have shorthands and there's no other references
   if (state.canOptimise && state.candidates.length) {
@@ -127,16 +127,14 @@ exports.Function = function (node, parent, scope, file) {
     );
   }
 
-  scope.assignTypeGeneric(rest.name, "Array");
-
   var loop = util.template("rest", {
     ARGUMENTS: argsId,
     ARRAY_KEY: arrKey,
     ARRAY_LEN: arrLen,
-    START: start,
-    ARRAY: rest,
-    KEY: key,
-    LEN: len,
+    START:     start,
+    ARRAY:     rest,
+    KEY:       key,
+    LEN:       len
   });
   loop._blockHoist = node.params.length + 1;
   node.body.body.unshift(loop);
diff --git a/src/babel/transformation/transformers/es6/spread.js b/src/babel/transformation/transformers/es6/spread.js
index 4fe2b7d238..693553ded9 100644
--- a/src/babel/transformation/transformers/es6/spread.js
+++ b/src/babel/transformation/transformers/es6/spread.js
@@ -81,7 +81,7 @@ export function CallExpression(node, parent, scope) {
 
   var callee = node.callee;
 
-  if (t.isMemberExpression(callee)) {
+  if (this.get("callee").isMemberExpression()) {
     var temp = scope.generateTempBasedOnNode(callee.object);
     if (temp) {
       callee.object = t.assignmentExpression("=", temp, callee.object);
@@ -101,7 +101,7 @@ export function NewExpression(node, parent, scope, file) {
   var args = node.arguments;
   if (!hasSpread(args)) return;
 
-  var nativeType = t.isIdentifier(node.callee) && includes(t.NATIVE_TYPE_NAMES, node.callee.name);
+  var nativeType = this.get("callee").isIdentifier() && includes(t.NATIVE_TYPE_NAMES, node.callee.name);
 
   var nodes = build(args, scope);
 
diff --git a/src/babel/transformation/transformers/es6/symbols.js b/src/babel/transformation/transformers/es6/symbols.js
index fd3fe51b7e..03f7ab491f 100644
--- a/src/babel/transformation/transformers/es6/symbols.js
+++ b/src/babel/transformation/transformers/es6/symbols.js
@@ -7,7 +7,7 @@ export function UnaryExpression(node, parent, scope, file) {
 
   if (node.operator === "typeof") {
     var call = t.callExpression(file.addHelper("typeof"), [node.argument]);
-    if (t.isIdentifier(node.argument)) {
+    if (this.get("argument").isIdentifier()) {
       var undefLiteral = t.literal("undefined");
       return t.conditionalExpression(
         t.binaryExpression("===", t.unaryExpression("typeof", node.argument), undefLiteral),
diff --git a/src/babel/transformation/transformers/es6/tail-call.js b/src/babel/transformation/transformers/es6/tail-call.js
index e7439cdf5a..c0efe08ec5 100644
--- a/src/babel/transformation/transformers/es6/tail-call.js
+++ b/src/babel/transformation/transformers/es6/tail-call.js
@@ -6,7 +6,7 @@ import map from "lodash/collection/map";
 import * as t from "../../../types";
 
 exports.Function = function (node, parent, scope, file) {
-  var tailCall = new TailCallTransformer(node, scope, file);
+  var tailCall = new TailCallTransformer(this, scope, file);
   tailCall.run();
 };
 
@@ -18,11 +18,11 @@ function returnBlock(expr) {
 var firstPass = {
   enter(node, parent, scope, state) {
     if (this.isIfStatement()) {
-      if (t.isReturnStatement(node.alternate)) {
+      if (this.get("alternate").isReturnStatement()) {
         t.ensureBlock(node, "alternate");
       }
 
-      if (t.isReturnStatement(node.consequent)) {
+      if (this.get("consequent").isReturnStatement()) {
         t.ensureBlock(node, "consequent");
       }
     } else if (this.isReturnStatement()) {
@@ -85,17 +85,18 @@ var thirdPass = {
 };
 
 class TailCallTransformer {
-  constructor(node, scope, file) {
+  constructor(path, scope, file) {
     this.hasTailRecursion = false;
     this.needsArguments   = false;
     this.setsArguments    = false;
     this.needsThis        = false;
-    this.ownerId          = node.id;
+    this.ownerId          = path.node.id;
     this.vars             = [];
 
     this.scope = scope;
+    this.path  = path;
     this.file  = file;
-    this.node  = node;
+    this.node  = path.node;
   }
 
   getArgumentsId() {
@@ -142,8 +143,8 @@ class TailCallTransformer {
   hasDeopt() {
     // check if the ownerId has been reassigned, if it has then it's not safe to
     // perform optimisations
-    var ownerIdInfo = this.scope.getBindingInfo(this.ownerId.name);
-    return ownerIdInfo && ownerIdInfo.reassigned;
+    var ownerIdInfo = this.scope.getBinding(this.ownerId.name);
+    return ownerIdInfo && !ownerIdInfo.constant;
   }
 
   run() {
@@ -156,7 +157,7 @@ class TailCallTransformer {
     if (!ownerId) return;
 
     // traverse the function and look for tail recursion
-    scope.traverse(node, firstPass, this);
+    this.path.traverse(firstPass, this);
 
     if (!this.hasTailRecursion) return;
 
@@ -167,10 +168,10 @@ class TailCallTransformer {
 
     //
 
-    scope.traverse(node, secondPass, this);
+    this.path.traverse(secondPass, this);
 
     if (!this.needsThis || !this.needsArguments) {
-      scope.traverse(node, thirdPass, this);
+      this.path.traverse(thirdPass, this);
     }
 
     var body = t.ensureBlock(node).body;
diff --git a/src/babel/transformation/transformers/es6/template-literals.js b/src/babel/transformation/transformers/es6/template-literals.js
index 9bee577561..537f57bde1 100644
--- a/src/babel/transformation/transformers/es6/template-literals.js
+++ b/src/babel/transformation/transformers/es6/template-literals.js
@@ -9,11 +9,11 @@ export function check(node) {
 }
 
 export function TaggedTemplateExpression(node, parent, scope, file) {
-  var args = [];
   var quasi = node.quasi;
+  var args  = [];
 
   var strings = [];
-  var raw = [];
+  var raw     = [];
 
   for (var i = 0; i < quasi.quasis.length; i++) {
     var elem = quasi.quasis[i];
diff --git a/src/babel/transformation/transformers/es7/abstract-references.js b/src/babel/transformation/transformers/es7/abstract-references.js
index 7713b41444..79f6415fad 100644
--- a/src/babel/transformation/transformers/es7/abstract-references.js
+++ b/src/babel/transformation/transformers/es7/abstract-references.js
@@ -4,6 +4,7 @@ import * as util from  "../../../util";
 import * as t from "../../../types";
 
 export var experimental = true;
+export var optional = true;
 
 var container = function (parent, call, ret, file) {
   if (t.isExpressionStatement(parent) && !file.isConsequenceExpressionStatement(parent)) {
diff --git a/src/babel/transformation/transformers/es7/comprehensions.js b/src/babel/transformation/transformers/es7/comprehensions.js
index 98484701b0..901f42e7e2 100644
--- a/src/babel/transformation/transformers/es7/comprehensions.js
+++ b/src/babel/transformation/transformers/es7/comprehensions.js
@@ -4,6 +4,7 @@ import * as util from  "../../../util";
 import * as t from "../../../types";
 
 export var experimental = true;
+export var optional = true;
 
 export function ComprehensionExpression(node, parent, scope, file) {
   var callback = array;
diff --git a/src/babel/transformation/transformers/es7/exponentiation-operator.js b/src/babel/transformation/transformers/es7/exponentiation-operator.js
index da988d07dd..e5106b938c 100644
--- a/src/babel/transformation/transformers/es7/exponentiation-operator.js
+++ b/src/babel/transformation/transformers/es7/exponentiation-operator.js
@@ -4,6 +4,7 @@ import build from "../../helpers/build-binary-assignment-operator-transformer";
 import * as t from "../../../types";
 
 export var experimental = true;
+export var optional = true;
 
 var MATH_POW = t.memberExpression(t.identifier("Math"), t.identifier("pow"));
 
diff --git a/src/babel/transformation/transformers/es7/object-rest-spread.js b/src/babel/transformation/transformers/es7/object-rest-spread.js
index c5d7b08c3d..257064dbcd 100644
--- a/src/babel/transformation/transformers/es7/object-rest-spread.js
+++ b/src/babel/transformation/transformers/es7/object-rest-spread.js
@@ -3,6 +3,7 @@
 import * as t from "../../../types";
 
 export var experimental = true;
+export var optional = true;
 
 export function manipulateOptions(opts) {
   if (opts.whitelist.length) opts.whitelist.push("es6.destructuring");
diff --git a/src/babel/transformation/transformers/index.js b/src/babel/transformation/transformers/index.js
index e318ff6902..9b008d23c6 100644
--- a/src/babel/transformation/transformers/index.js
+++ b/src/babel/transformation/transformers/index.js
@@ -20,7 +20,6 @@ export default {
   "playground.objectGetterMemoization":    require("./playground/object-getter-memoization"),
 
   reactCompat:                             require("./other/react-compat"),
-  flow:                                    require("./other/flow"),
   react:                                   require("./other/react"),
 
   _modules:                                require("./internal/modules"),
@@ -45,6 +44,7 @@ export default {
   // needs to be before `_aliasFunction` due to define property closure
   "es6.properties.computed":               require("./es6/properties.computed"),
 
+  "optimisation.es6.forOf":                require("./optimisation/flow.for-of"),
   "es6.forOf":                             require("./es6/for-of"),
 
   "es6.regex.sticky":                      require("./es6/regex.sticky"),
@@ -110,5 +110,6 @@ export default {
   "utility.inlineExpressions":             require("./utility/inline-expressions"),
   "utility.deadCodeElimination":           require("./utility/dead-code-elimination"),
 
+  flow:                                    require("./other/flow"),
   _cleanUp:                                require("./internal/cleanup")
 };
diff --git a/src/babel/transformation/transformers/internal/alias-functions.js b/src/babel/transformation/transformers/internal/alias-functions.js
index b76e19ae50..649edd0c38 100644
--- a/src/babel/transformation/transformers/internal/alias-functions.js
+++ b/src/babel/transformation/transformers/internal/alias-functions.js
@@ -34,13 +34,13 @@ var functionVisitor = {
     }
 
     // traverse all child nodes of this function and find `arguments` and `this`
-    scope.traverse(node, functionChildrenVisitor, state);
+    this.traverse(functionChildrenVisitor, state);
 
     return this.skip();
   }
 };
 
-var go = function (getBody, node, scope) {
+function aliasFunction(getBody, path, scope) {
   var argumentsId;
   var thisId;
 
@@ -56,7 +56,7 @@ var go = function (getBody, node, scope) {
 
   // traverse the function and find all alias functions so we can alias
   // `arguments` and `this` if necessary
-  scope.traverse(node, functionVisitor, state);
+  path.traverse(functionVisitor, state);
 
   var body;
 
@@ -77,16 +77,16 @@ var go = function (getBody, node, scope) {
 };
 
 export function Program(node, parent, scope) {
-  go(function () {
+  aliasFunction(function () {
     return node.body;
-  }, node, scope);
+  }, this, scope);
 };
 
 export function FunctionDeclaration(node, parent, scope) {
-  go(function () {
+  aliasFunction(function () {
     t.ensureBlock(node);
     return node.body.body;
-  }, node, scope);
+  }, this, scope);
 }
 
 export { FunctionDeclaration as FunctionExpression };
diff --git a/src/babel/transformation/transformers/internal/modules.js b/src/babel/transformation/transformers/internal/modules.js
index 7ef5bc5302..50ecd3a7a8 100644
--- a/src/babel/transformation/transformers/internal/modules.js
+++ b/src/babel/transformation/transformers/internal/modules.js
@@ -50,7 +50,12 @@ export function ExportDeclaration(node, parent, scope) {
       return [getDeclar(), node];
     }
   } else {
-    if (t.isFunctionDeclaration(declar)) {
+    if (t.isClassDeclaration(declar)) {
+      // export class Foo {}
+      node.specifiers  = [t.importSpecifier(declar.id, declar.id)];
+      node.declaration = null;
+      return [getDeclar(), node];
+    } else if (t.isFunctionDeclaration(declar)) {
       // export function Foo() {}
       node.specifiers  = [t.importSpecifier(declar.id, declar.id)];
       node.declaration = null;
@@ -59,7 +64,7 @@ export function ExportDeclaration(node, parent, scope) {
     } else if (t.isVariableDeclaration(declar)) {
       // export var foo = "bar";
       var specifiers = [];
-      var bindings = t.getBindingIdentifiers(declar);
+      var bindings = this.get("declaration").getBindingIdentifiers();
       for (var key in bindings) {
         var id = bindings[key];
         specifiers.push(t.exportSpecifier(id, id));
diff --git a/src/babel/transformation/transformers/optimisation/flow.for-of.js b/src/babel/transformation/transformers/optimisation/flow.for-of.js
new file mode 100644
index 0000000000..5e0237d700
--- /dev/null
+++ b/src/babel/transformation/transformers/optimisation/flow.for-of.js
@@ -0,0 +1,11 @@
+import { _ForOfStatementArray } from "../es6/for-of";
+import * as t from "../../../types";
+
+export var check = t.isForOfStatement;
+export var optional = true;
+
+export function ForOfStatement(node, parent, scope, file) {
+  if (this.get("right").isTypeGeneric("Array")) {
+    return _ForOfStatementArray.call(this, node, scope, file);
+  }
+}
diff --git a/src/babel/transformation/transformers/other/flow.js b/src/babel/transformation/transformers/other/flow.js
index 4f8126f9f9..bb6bf4c393 100644
--- a/src/babel/transformation/transformers/other/flow.js
+++ b/src/babel/transformation/transformers/other/flow.js
@@ -29,5 +29,5 @@ export function ImportDeclaration(node) {
 }
 
 export function ExportDeclaration(node) {
-  if (t.isTypeAlias(node.declaration)) this.remove();
+  if (this.get("declaration").isTypeAlias()) this.remove();
 }
diff --git a/src/babel/transformation/transformers/other/runtime.js b/src/babel/transformation/transformers/other/runtime.js
index a137603e8c..ec2de99541 100644
--- a/src/babel/transformation/transformers/other/runtime.js
+++ b/src/babel/transformation/transformers/other/runtime.js
@@ -4,7 +4,7 @@ import core from "core-js/library";
 import has from "lodash/object/has";
 import * as t from "../../../types";
 
-var isSymboliterator = t.buildMatchMemberExpression("Symbol.iterator");
+var isSymbolIterator = t.buildMatchMemberExpression("Symbol.iterator");
 
 var coreHas = function (node) {
   return node.name !== "_" && has(core, node.name);
@@ -47,7 +47,7 @@ var astVisitor = {
       if (!callee.computed) return false;
 
       prop = callee.property;
-      if (!isSymboliterator(prop)) return false;
+      if (!isSymbolIterator(prop)) return false;
 
       return util.template("corejs-iterator", {
         CORE_ID: file.get("coreIdentifier"),
@@ -59,7 +59,7 @@ var astVisitor = {
       if (node.operator !== "in") return;
 
       var left = node.left;
-      if (!isSymboliterator(left)) return;
+      if (!isSymbolIterator(left)) return;
 
       return util.template("corejs-is-iterator", {
         CORE_ID: file.get("coreIdentifier"),
@@ -76,7 +76,7 @@ export function manipulateOptions(opts) {
 }
 
 export function Program(node, parent, scope, file) {
-  scope.traverse(node, astVisitor, file);
+  this.traverse(astVisitor, file);
 }
 
 export function pre(file) {
diff --git a/src/babel/transformation/transformers/playground/mallet-operator.js b/src/babel/transformation/transformers/playground/mallet-operator.js
index 25e6896a45..1d51716fe0 100644
--- a/src/babel/transformation/transformers/playground/mallet-operator.js
+++ b/src/babel/transformation/transformers/playground/mallet-operator.js
@@ -3,6 +3,7 @@ import build from "../../helpers/build-conditional-assignment-operator-transform
 import * as t from "../../../types";
 
 export var playground = true;
+export var optional = true;
 
 build(exports, {
   is(node, file) {
diff --git a/src/babel/transformation/transformers/playground/memoization-operator.js b/src/babel/transformation/transformers/playground/memoization-operator.js
index 7c63ad102a..c399166eef 100644
--- a/src/babel/transformation/transformers/playground/memoization-operator.js
+++ b/src/babel/transformation/transformers/playground/memoization-operator.js
@@ -2,6 +2,7 @@ import build from "../../helpers/build-conditional-assignment-operator-transform
 import * as t from "../../../types";
 
 export var playground = true;
+export var optional = true;
 
 build(exports, {
   is(node) {
diff --git a/src/babel/transformation/transformers/playground/method-binding.js b/src/babel/transformation/transformers/playground/method-binding.js
index 3bea826a5a..86ec1312ae 100644
--- a/src/babel/transformation/transformers/playground/method-binding.js
+++ b/src/babel/transformation/transformers/playground/method-binding.js
@@ -1,9 +1,10 @@
 import * as t from "../../../types";
 
 export var playground = true;
+export var optional = true;
 
-export function BindMemberExpression(node, parent, scope) {
-  console.error("Method binding is deprecated and will be removed in 5.0.0");
+export function BindMemberExpression(node, parent, scope, file) {
+  file.log.deprecate("Method binding is deprecated and will be removed in 5.0.0");
 
   var object = node.object;
   var prop   = node.property;
@@ -26,8 +27,8 @@ export function BindMemberExpression(node, parent, scope) {
   }
 }
 
-export function BindFunctionExpression(node, parent, scope) {
-  console.error("Method binding is deprecated and will be removed in 5.0.0");
+export function BindFunctionExpression(node, parent, scope, file) {
+  file.log.deprecate("Method binding is deprecated and will be removed in 5.0.0");
 
   var buildCall = function (args) {
     var param = scope.generateUidIdentifier("val");
diff --git a/src/babel/transformation/transformers/playground/object-getter-memoization.js b/src/babel/transformation/transformers/playground/object-getter-memoization.js
index e2f0ac6487..8c117811a7 100644
--- a/src/babel/transformation/transformers/playground/object-getter-memoization.js
+++ b/src/babel/transformation/transformers/playground/object-getter-memoization.js
@@ -1,6 +1,7 @@
 import * as t from "../../../types";
 
 export var playground = true;
+export var optional = true;
 
 var visitor = {
   enter(node, parent, scope, state) {
@@ -20,10 +21,9 @@ export function MethodDefinition(node, parent, scope, file) {
   if (node.kind !== "memo") return;
   node.kind = "get";
 
-  console.error("Object getter memoization is deprecated and will be removed in 5.0.0");
+  file.log.deprecate("Object getter memoization is deprecated and will be removed in 5.0.0");
 
-  var value = node.value;
-  t.ensureBlock(value);
+  t.ensureBlock(node.value);
 
   var key = node.key;
 
@@ -36,7 +36,7 @@ export function MethodDefinition(node, parent, scope, file) {
     file: file
   };
 
-  scope.traverse(value, visitor, state);
+  this.get("value").traverse(visitor, state);
 
   return node;
 }
diff --git a/src/babel/transformation/transformers/utility/dead-code-elimination.js b/src/babel/transformation/transformers/utility/dead-code-elimination.js
index 3dd7252ae3..bda19f668d 100644
--- a/src/babel/transformation/transformers/utility/dead-code-elimination.js
+++ b/src/babel/transformation/transformers/utility/dead-code-elimination.js
@@ -20,7 +20,7 @@ function toStatements(node) {
 export var optional = true;
 
 export function ConditionalExpression(node, parent, scope) {
-  var evaluateTest = t.evaluateTruthy(node.test, scope);
+  var evaluateTest = this.get("test").evaluateTruthy();
   if (evaluateTest === true) {
     return node.consequent;
   } else if (evaluateTest === false) {
@@ -32,9 +32,8 @@ export var IfStatement = {
   exit(node, parent, scope) {
     var consequent = node.consequent;
     var alternate  = node.alternate;
-    var test       = node.test;
 
-    var evaluateTest = t.evaluateTruthy(test, scope);
+    var evaluateTest = this.get("test").evaluateTruthy();
 
     // we can check if a test will be truthy 100% and if so then we can inline
     // the consequent and completely ignore the alternate
diff --git a/src/babel/transformation/transformers/utility/inline-environment-variables.js b/src/babel/transformation/transformers/utility/inline-environment-variables.js
index 5c62f53a6e..5e2cabb55c 100644
--- a/src/babel/transformation/transformers/utility/inline-environment-variables.js
+++ b/src/babel/transformation/transformers/utility/inline-environment-variables.js
@@ -6,7 +6,7 @@ var match = t.buildMatchMemberExpression("process.env");
 
 export function MemberExpression(node) {
   if (match(node.object)) {
-    var key = t.toComputedKey(node, node.property);
+    var key = this.toComputedKey();
     if (t.isLiteral(key)) {
       return t.valueToNode(process.env[key.value]);
     }
diff --git a/src/babel/transformation/transformers/utility/inline-expressions.js b/src/babel/transformation/transformers/utility/inline-expressions.js
index 9b77422502..f1be106014 100644
--- a/src/babel/transformation/transformers/utility/inline-expressions.js
+++ b/src/babel/transformation/transformers/utility/inline-expressions.js
@@ -3,7 +3,7 @@ import * as t from "../../../types";
 export var optional = true;
 
 export function Expression(node, parent, scope) {
-  var res = t.evaluate(node, scope);
+  var res = this.evaluate();
   if (res.confident) return t.valueToNode(res.value);
 }
 
diff --git a/src/babel/transformation/transformers/utility/remove-console.js b/src/babel/transformation/transformers/utility/remove-console.js
index 791b17c9f4..9fe1f491a9 100644
--- a/src/babel/transformation/transformers/utility/remove-console.js
+++ b/src/babel/transformation/transformers/utility/remove-console.js
@@ -1,11 +1,9 @@
 import * as t from "../../../types";
 
-var isConsole = t.buildMatchMemberExpression("console", true);
-
 export var optional = true;
 
 export function CallExpression(node, parent) {
-  if (isConsole(node.callee)) {
+  if (this.get("callee").matchesPattern("console", true)) {
     if (t.isExpressionStatement(parent)) {
       this.parentPath.remove();
     } else {
diff --git a/src/babel/transformation/transformers/validation/react.js b/src/babel/transformation/transformers/validation/react.js
index f8cbc58ffb..536aff1768 100644
--- a/src/babel/transformation/transformers/validation/react.js
+++ b/src/babel/transformation/transformers/validation/react.js
@@ -14,7 +14,7 @@ function check(source, file) {
 }
 
 export function CallExpression(node, parent, scope, file) {
-  if (t.isIdentifier(node.callee, { name: "require" }) && node.arguments.length === 1) {
+  if (this.get("callee").isIdentifier({ name: "require" }) && node.arguments.length === 1) {
     check(node.arguments[0], file);
   }
 }
diff --git a/src/babel/traversal/binding.js b/src/babel/traversal/binding.js
new file mode 100644
index 0000000000..ee2cdddf0a
--- /dev/null
+++ b/src/babel/traversal/binding.js
@@ -0,0 +1,68 @@
+import * as t from "../types";
+
+export default class Binding {
+  constructor({ identifier, scope, path, kind }) {
+    this.identifier = identifier;
+    this.constant   = true;
+    this.scope      = scope;
+    this.path       = path;
+    this.kind       = kind;
+  }
+
+  /**
+   * Description
+   */
+
+   setTypeAnnotation() {
+    var typeInfo = this.path.getTypeAnnotation();
+    this.typeAnnotationInferred = typeInfo.inferred;
+    this.typeAnnotation         = typeInfo.annotation;
+   }
+
+  /**
+   * Description
+   */
+
+  isTypeGeneric(): boolean {
+    return this.path.isTypeGeneric(...arguments);
+  }
+
+  /**
+   * Description
+   */
+
+  assignTypeGeneric(type: Object, params?) {
+    var typeParams = null;
+    if (params) params = t.typeParameterInstantiation(params);
+    this.assignType(t.genericTypeAnnotation(t.identifier(type), typeParams));
+  }
+
+  /**
+   * Description
+   */
+
+  assignType(type: Object) {
+    this.typeAnnotation = type;
+  }
+
+  /**
+   * Description
+   */
+
+  reassign() {
+    this.constant = false;
+
+    if (this.typeAnnotationInferred) {
+      // destroy the inferred typeAnnotation
+      this.typeAnnotation = null;
+    }
+  }
+
+  /**
+   * Description
+   */
+
+  isCompatibleWithType(newType): boolean {
+    return false;
+  }
+}
diff --git a/src/babel/traversal/index.js b/src/babel/traversal/index.js
index 86c94d9fbe..c36162f7df 100644
--- a/src/babel/traversal/index.js
+++ b/src/babel/traversal/index.js
@@ -1,10 +1,8 @@
-module.exports = traverse;
-
 import TraversalContext from "./context";
 import includes from "lodash/collection/includes";
 import * as t from "../types";
 
-function traverse(parent, opts, scope, state) {
+export default function traverse(parent, opts, scope, state, parentPath) {
   if (!parent) return;
 
   if (!opts.noScope && !scope) {
@@ -20,10 +18,10 @@ function traverse(parent, opts, scope, state) {
   // array of nodes
   if (Array.isArray(parent)) {
     for (var i = 0; i < parent.length; i++) {
-      traverse.node(parent[i], opts, scope, state);
+      traverse.node(parent[i], opts, scope, state, parentPath);
     }
   } else {
-    traverse.node(parent, opts, scope, state);
+    traverse.node(parent, opts, scope, state, parentPath);
   }
 }
 
@@ -42,7 +40,6 @@ traverse.node = function (node, opts, scope, state, parentPath) {
 function clearNode(node) {
   node._declarations = null;
   node.extendedRange = null;
-  node._scopeInfo    = null;
   node._paths        = null;
   node.tokens        = null;
   node.range         = null;
diff --git a/src/babel/traversal/path.js b/src/babel/traversal/path.js
deleted file mode 100644
index fb5c204050..0000000000
--- a/src/babel/traversal/path.js
+++ /dev/null
@@ -1,226 +0,0 @@
-import traverse from "./index";
-import includes from "lodash/collection/includes";
-import Scope from "./scope";
-import * as t from "../types";
-
-export default class TraversalPath {
-  constructor(parent, container) {
-    this.container = container;
-    this.parent    = parent;
-    this.data      = {};
-  }
-
-  static get(parentPath, context, parent, container, key) {
-    var targetNode = container[key];
-    var paths = container._paths ||= [];
-    var path;
-
-    for (var i = 0; i < paths.length; i++) {
-      var pathCheck = paths[i];
-      if (pathCheck.node === targetNode) {
-        path = pathCheck;
-        break;
-      }
-    }
-
-    if (!path) {
-      path = new TraversalPath(parent, container);
-      paths.push(path);
-    }
-
-    path.setContext(parentPath, context, key);
-
-    return path;
-  }
-
-  static getScope(node, parent, scope) {
-    var ourScope = scope;
-
-    // we're entering a new scope so let's construct it!
-    if (t.isScope(node, parent)) {
-      ourScope = new Scope(node, parent, scope);
-    }
-
-    return ourScope;
-  }
-
-  insertBefore(node) {
-
-  }
-
-  insertAfter(node) {
-
-  }
-
-  setData(key, val) {
-    return this.data[key] = val;
-  }
-
-  getData(key) {
-    return this.data[key];
-  }
-
-  setScope() {
-    this.scope = TraversalPath.getScope(this.node, this.parent, this.context.scope);
-  }
-
-  setContext(parentPath, context, key) {
-    this.shouldSkip = false;
-    this.shouldStop = false;
-
-    this.parentPath = parentPath || this.parentPath;
-    this.context    = context;
-    this.state      = context.state;
-    this.opts       = context.opts;
-    this.key        = key;
-
-    this.setScope();
-  }
-
-  remove() {
-    this._refresh(this.node, []);
-    this.container[this.key] = null;
-    this.flatten();
-  }
-
-  skip() {
-    this.shouldSkip = true;
-  }
-
-  stop() {
-    this.shouldStop = true;
-    this.shouldSkip = true;
-  }
-
-  flatten() {
-    this.context.flatten();
-  }
-
-  _refresh(oldNode, newNodes) {
-    // todo
-  }
-
-  refresh() {
-    var node = this.node;
-    this._refresh(node, [node]);
-  }
-
-  get node() {
-    return this.container[this.key];
-  }
-
-  set node(replacement) {
-    if (!replacement) return this.remove();
-
-    var oldNode      = this.node;
-    var isArray      = Array.isArray(replacement);
-    var replacements = isArray ? replacement : [replacement];
-
-    // inherit comments from original node to the first replacement node
-    var inheritTo = replacements[0];
-    if (inheritTo) t.inheritsComments(inheritTo, oldNode);
-
-    // replace the node
-    this.container[this.key] = replacement;
-
-    // potentially create new scope
-    this.setScope();
-
-    // refresh scope with new/removed bindings
-    this._refresh(oldNode, replacements);
-
-    var file = this.scope && this.scope.file;
-    if (file) {
-      for (var i = 0; i < replacements.length; i++) {
-        file.checkNode(replacements[i], this.scope);
-      }
-    }
-
-    // we're replacing a statement or block node with an array of statements so we better
-    // ensure that it's a block
-    if (isArray) {
-      if (includes(t.STATEMENT_OR_BLOCK_KEYS, this.key) && !t.isBlockStatement(this.container)) {
-        t.ensureBlock(this.container, this.key);
-      }
-
-      this.flatten();
-      // TODO: duplicate internal path metadata across the new node paths
-    }
-  }
-
-  call(key) {
-    var node = this.node;
-    if (!node) return;
-
-    var opts = this.opts;
-    var fn   = opts[key] || opts;
-    if (opts[node.type]) fn = opts[node.type][key] || fn;
-
-    var replacement = fn.call(this, node, this.parent, this.scope, this.state);
-
-    if (replacement) {
-      this.node = replacement;
-    }
-  }
-
-  isBlacklisted() {
-    var blacklist = this.opts.blacklist;
-    return blacklist && blacklist.indexOf(this.node.type) > -1;
-  }
-
-  visit() {
-    if (this.isBlacklisted()) return false;
-
-    this.call("enter");
-
-    if (this.shouldSkip) {
-      return this.shouldStop;
-    }
-
-    var node = this.node;
-    var opts = this.opts;
-
-    if (node) {
-      if (Array.isArray(node)) {
-        // traverse over these replacement nodes we purposely don't call exitNode
-        // as the original node has been destroyed
-        for (var i = 0; i < node.length; i++) {
-          traverse.node(node[i], opts, this.scope, this.state, this);
-        }
-      } else {
-        traverse.node(node, opts, this.scope, this.state, this);
-        this.call("exit");
-      }
-    }
-
-    return this.shouldStop;
-  }
-
-  get(key) {
-    return TraversalPath.get(this, this.context, this.node, this.node, key);
-  }
-
-  isReferencedIdentifier(opts) {
-    return t.isReferencedIdentifier(this.node, this.parent, opts);
-  }
-
-  isReferenced() {
-    return t.isReferenced(this.node, this.parent);
-  }
-
-  isScope() {
-    return t.isScope(this.node, this.parent);
-  }
-
-  getBindingIdentifiers() {
-    return t.getBindingIdentifiers(this.node);
-  }
-}
-
-for (var i = 0; i < t.TYPES.length; i++) {
-  let type = t.TYPES[i];
-  let typeKey = `is${type}`;
-  TraversalPath.prototype[typeKey] = function (opts) {
-    return t[typeKey](this.node, opts);
-  };
-}
diff --git a/src/babel/traversal/path/conversion.js b/src/babel/traversal/path/conversion.js
new file mode 100644
index 0000000000..24293c7d8b
--- /dev/null
+++ b/src/babel/traversal/path/conversion.js
@@ -0,0 +1,24 @@
+import * as t from "../../types";
+
+/**
+ * Description
+ */
+
+export function toComputedKey(): Object {
+  var node = this.node;
+
+  var key;
+  if (this.isMemberExpression()) {
+    key = node.property;
+  } else if (this.isProperty()) {
+    key = node.key;
+  } else {
+    throw new ReferenceError("todo");
+  }
+
+  if (!node.computed) {
+    if (t.isIdentifier(key)) key = t.literal(key.name);
+  }
+
+  return key;
+}
diff --git a/src/babel/types/evaluators.js b/src/babel/traversal/path/evaluation.js
similarity index 65%
rename from src/babel/types/evaluators.js
rename to src/babel/traversal/path/evaluation.js
index 163de2581e..2070ab5d2b 100644
--- a/src/babel/types/evaluators.js
+++ b/src/babel/traversal/path/evaluation.js
@@ -1,5 +1,3 @@
-import * as t from "./index";
-
 /**
  * Walk the input `node` and statically evaluate if it's truthy.
  *
@@ -18,15 +16,15 @@ import * as t from "./index";
  *
  */
 
-export function evaluateTruthy(node: Object, scope: Scope): boolean {
-  var res = evaluate(node, scope);
+export function evaluateTruthy(): boolean {
+  var res = this.evaluate();
   if (res.confident) return !!res.value;
 }
 
 /**
  * Walk the input `node` and statically evaluate it.
  *
- * Returns an pbject in the form `{ confident, value }`. `confident` indicates
+ * Returns an object in the form `{ confident, value }`. `confident` indicates
  * whether or not we had to drop out of evaluating the expression because of
  * hitting an unknown node that we couldn't confidently find the value of.
  *
@@ -38,24 +36,27 @@ export function evaluateTruthy(node: Object, scope: Scope): boolean {
  *
  */
 
-export function evaluate(node: Object, scope: Scope): { confident: boolean; value: any } {
+export function evaluate(): { confident: boolean; value: any } {
   var confident = true;
 
-  var value = evaluate(node);
+  var value = evaluate(this);
   if (!confident) value = undefined;
   return {
     confident: confident,
     value:     value
   };
 
-  function evaluate(node) {
+  function evaluate(path) {
     if (!confident) return;
 
-    if (t.isSequenceExpression(node)) {
-      return evaluate(node.expressions[node.expressions.length - 1]);
+    var node = path.node;
+
+    if (path.isSequenceExpression()) {
+      var exprs = path.get("expressions");
+      return evaluate(exprs[exprs.length - 1]);
     }
 
-    if (t.isLiteral(node)) {
+    if (path.isLiteral()) {
       if (node.regex && node.value === null) {
         // we have a regex and we can't represent it natively
       } else {
@@ -63,24 +64,29 @@ export function evaluate(node: Object, scope: Scope): { confident: boolean; valu
       }
     }
 
-    if (t.isConditionalExpression(node)) {
-      if (evaluate(node.test)) {
-        return evaluate(node.consequent);
+    if (path.isConditionalExpression()) {
+      if (evaluate(path.get("test"))) {
+        return evaluate(path.get("consequent"));
       } else {
-        return evaluate(node.alternate);
+        return evaluate(path.get("alternate"));
       }
     }
 
-    if (t.isIdentifier(node)) {
-      if (node.name === "undefined") {
-        return undefined;
+    if (path.isIdentifier({ name: "undefined" })) {
+      return undefined;
+    }
+
+    if (path.isIdentifier() || path.isMemberExpression()) {
+      path = path.resolve();
+      if (path) {
+        return evaluate(path);
       } else {
-        return evaluate(scope.getImmutableBindingValue(node.name));
+        return confident = false;
       }
     }
 
-    if (t.isUnaryExpression(node, { prefix: true })) {
-      var arg = evaluate(node.argument);
+    if (path.isUnaryExpression({ prefix: true })) {
+      var arg = evaluate(path.get("argument"));
       switch (node.operator) {
         case "void": return undefined;
         case "!": return !arg;
@@ -89,13 +95,13 @@ export function evaluate(node: Object, scope: Scope): { confident: boolean; valu
       }
     }
 
-    if (t.isArrayExpression(node) || t.isObjectExpression(node)) {
+    if (path.isArrayExpression() || path.isObjectExpression()) {
       // we could evaluate these but it's probably impractical and not very useful
     }
 
-    if (t.isLogicalExpression(node)) {
-      let left = evaluate(node.left);
-      let right = evaluate(node.right);
+    if (path.isLogicalExpression()) {
+      let left = evaluate(path.get("left"));
+      let right = evaluate(path.get("right"));
 
       switch (node.operator) {
         case "||": return left || right;
@@ -103,9 +109,9 @@ export function evaluate(node: Object, scope: Scope): { confident: boolean; valu
       }
     }
 
-    if (t.isBinaryExpression(node)) {
-      let left = evaluate(node.left);
-      let right = evaluate(node.right);
+    if (path.isBinaryExpression()) {
+      let left = evaluate(path.get("left"));
+      let right = evaluate(path.get("right"));
 
       switch (node.operator) {
         case "-": return left - right;
diff --git a/src/babel/traversal/path/index.js b/src/babel/traversal/path/index.js
new file mode 100644
index 0000000000..64fed848f0
--- /dev/null
+++ b/src/babel/traversal/path/index.js
@@ -0,0 +1,464 @@
+import isBoolean from "lodash/lang/isBoolean";
+import isNumber from "lodash/lang/isNumber";
+import isRegExp from "lodash/lang/isRegExp";
+import isString from "lodash/lang/isString";
+import traverse from "../index";
+import includes from "lodash/collection/includes";
+import assign from "lodash/object/assign";
+import Scope from "../scope";
+import * as t from "../../types";
+
+export default class TraversalPath {
+  constructor(parent, container) {
+    this.container = container;
+    this.parent    = parent;
+    this.data      = {};
+  }
+
+  static get(parentPath: TraversalPath, context?: TraversalContext, parent, container, key, file?: File) {
+    var targetNode = container[key];
+    var paths = container._paths ||= [];
+    var path;
+
+    for (var i = 0; i < paths.length; i++) {
+      var pathCheck = paths[i];
+      if (pathCheck.node === targetNode) {
+        path = pathCheck;
+        break;
+      }
+    }
+
+    if (!path) {
+      path = new TraversalPath(parent, container);
+      paths.push(path);
+    }
+
+    path.setContext(parentPath, context, key, file);
+
+    return path;
+  }
+
+  static getScope(path: TraversalPath, scope: Scope, file?: File) {
+    var ourScope = scope;
+
+    // we're entering a new scope so let's construct it!
+    if (path.isScope()) {
+      ourScope = new Scope(path, scope, file);
+    }
+
+    return ourScope;
+  }
+
+  insertBefore(node) {
+
+  }
+
+  insertAfter(node) {
+
+  }
+
+  setData(key, val) {
+    return this.data[key] = val;
+  }
+
+  getData(key, def) {
+    var val = this.data[key];
+    if (!val && def) val = this.data[key] = def;
+    return val;
+  }
+
+  setScope(file?) {
+    this.scope = TraversalPath.getScope(this, this.context && this.context.scope, file);
+  }
+
+  setContext(parentPath, context, key, file?) {
+    this.shouldSkip = false;
+    this.shouldStop = false;
+
+    this.parentPath = parentPath || this.parentPath;
+    this.key        = key;
+
+    if (context) {
+      this.context = context;
+      this.state   = context.state;
+      this.opts    = context.opts;
+    }
+
+    this.setScope(file);
+  }
+
+  remove() {
+    this._refresh(this.node, []);
+    this.container[this.key] = null;
+    this.flatten();
+  }
+
+  skip() {
+    this.shouldSkip = true;
+  }
+
+  stop() {
+    this.shouldStop = true;
+    this.shouldSkip = true;
+  }
+
+  flatten() {
+    this.context.flatten();
+  }
+
+  _refresh(oldNode, newNodes) {
+    // todo
+  }
+
+  refresh() {
+    var node = this.node;
+    this._refresh(node, [node]);
+  }
+
+  errorWithNode(msg, Error = SyntaxError) {
+    var loc = this.node.loc.start;
+    var err = new Error(`Line ${loc.line}: ${msg}`);
+    err.loc = loc;
+    return err;
+  }
+
+  get node() {
+    return this.container[this.key];
+  }
+
+  set node(replacement) {
+    if (!replacement) return this.remove();
+
+    var oldNode      = this.node;
+    var isArray      = Array.isArray(replacement);
+    var replacements = isArray ? replacement : [replacement];
+
+    // inherit comments from original node to the first replacement node
+    var inheritTo = replacements[0];
+    if (inheritTo) t.inheritsComments(inheritTo, oldNode);
+
+    // replace the node
+    this.container[this.key] = replacement;
+
+    // potentially create new scope
+    this.setScope();
+
+    var file = this.scope && this.scope.file;
+    if (file) {
+      for (var i = 0; i < replacements.length; i++) {
+        file.checkNode(replacements[i], this.scope);
+      }
+    }
+
+    // we're replacing a statement or block node with an array of statements so we better
+    // ensure that it's a block
+    if (isArray) {
+      if (includes(t.STATEMENT_OR_BLOCK_KEYS, this.key) && !t.isBlockStatement(this.container)) {
+        t.ensureBlock(this.container, this.key);
+      }
+
+      this.flatten();
+      // TODO: duplicate internal path metadata across the new node paths
+    }
+  }
+
+  call(key) {
+    var node = this.node;
+    if (!node) return;
+
+    var opts = this.opts;
+    var fn   = opts[key] || opts;
+    if (opts[node.type]) fn = opts[node.type][key] || fn;
+
+    var replacement = fn.call(this, node, this.parent, this.scope, this.state);
+
+    if (replacement) {
+      this.node = replacement;
+    }
+  }
+
+  isBlacklisted(): boolean {
+    var blacklist = this.opts.blacklist;
+    return blacklist && blacklist.indexOf(this.node.type) > -1;
+  }
+
+  visit(): boolean {
+    if (this.isBlacklisted()) return false;
+
+    this.call("enter");
+
+    if (this.shouldSkip) {
+      return this.shouldStop;
+    }
+
+    var node = this.node;
+    var opts = this.opts;
+
+    if (node) {
+      if (Array.isArray(node)) {
+        // traverse over these replacement nodes we purposely don't call exitNode
+        // as the original node has been destroyed
+        for (var i = 0; i < node.length; i++) {
+          traverse.node(node[i], opts, this.scope, this.state, this);
+        }
+      } else {
+        traverse.node(node, opts, this.scope, this.state, this);
+        this.call("exit");
+      }
+    }
+
+    return this.shouldStop;
+  }
+
+  get(key) {
+    var node = this.node;
+    var container = node[key];
+    if (Array.isArray(container)) {
+      return container.map((_, i) => {
+        return TraversalPath.get(this, this.context, node, container, i);
+      });
+    } else {
+      return TraversalPath.get(this, this.context, node, node, key);
+    }
+  }
+
+  has(key): boolean {
+    return !!this.node[key];
+  }
+
+  is(key): boolean {
+    return this.has(key);
+  }
+
+  isnt(key): boolean {
+    return !this.has(key);
+  }
+
+  getTypeAnnotation(): {
+    inferred: boolean;
+    annotation: ?Object;
+  } {
+    if (this.typeInfo) {
+      return this.typeInfo;
+    }
+
+    var info = this.typeInfo = {
+      inferred: false,
+      annotation: null
+    };
+
+    var type = this.node.typeAnnotation;
+
+    if (!type) {
+      info.inferred = true;
+      type = this.inferType(this);
+    }
+
+    if (type) {
+      if (t.isTypeAnnotation(type)) type = type.typeAnnotation;
+      info.annotation = type;
+    }
+
+    return info;
+  }
+
+  resolve(): ?TraversalPath {
+    if (this.isVariableDeclarator()) {
+      if (this.get("id").isIdentifier()) {
+        return this.get("init").resolve();
+      } else {
+        // otherwise it's a request for a destructuring declarator and i'm not
+        // ready to resolve those just yet
+      }
+    } else if (this.isIdentifier()) {
+      var binding = this.scope.getBinding(this.node.name);
+      if (!binding || !binding.constant) return;
+
+      if (binding.path === this) {
+        return this;
+      } else {
+        return binding.path.resolve();
+      }
+    } else if (this.isMemberExpression()) {
+      // this is dangerous, as non-direct target assignments will mutate it's state
+      // making this resolution inaccurate
+
+      var targetKey = this.toComputedKey();
+      if (!t.isLiteral(targetKey)) return;
+      var targetName = targetKey.value;
+
+      var target = this.get("object").resolve();
+      if (!target || !target.isObjectExpression()) return;
+
+      var props = target.get("properties");
+      for (var i = 0; i < props.length; i++) {
+        var prop = props[i];
+        if (!prop.isProperty()) continue;
+
+        var key = prop.get("key");
+
+        // { foo: obj }
+        var match = prop.isnt("computed") && key.isIdentifier({ name: targetName });
+
+        // { "foo": "obj" } or { ["foo"]: "obj" }
+        match ||= key.isLiteral({ value: targetName });
+
+        if (match) return prop.get("value");
+      }
+    } else {
+      return this;
+    }
+  }
+
+  inferType(path: TraversalPath): ?Object {
+    path = path.resolve();
+    if (!path) return;
+
+    if (path.isRestElement() || path.parentPath.isRestElement() || path.isArrayExpression()) {
+      return t.genericTypeAnnotation(t.identifier("Array"));
+    }
+
+    if (path.parentPath.isTypeCastExpression()) {
+      return path.parentPath.node.typeAnnotation;
+    }
+
+    if (path.isTypeCastExpression()) {
+      return path.node.typeAnnotation;
+    }
+
+    if (path.isObjectExpression()) {
+      return t.genericTypeAnnotation(t.identifier("Object"));
+    }
+
+    if (path.isFunction()) {
+      return t.identifier("Function");
+    }
+
+    if (path.isLiteral()) {
+      var value = path.node.value;
+      if (isString(value)) return t.stringTypeAnnotation();
+      if (isNumber(value)) return t.numberTypeAnnotation();
+      if (isBoolean(value)) return t.booleanTypeAnnotation();
+    }
+
+    if (path.isCallExpression()) {
+      var callee = path.get("callee").resolve();
+      if (callee && callee.isFunction()) return callee.node.returnType;
+    }
+  }
+
+  isScope(): boolean {
+    return t.isScope(this.node, this.parent);
+  }
+
+  isReferencedIdentifier(opts): boolean {
+    return t.isReferencedIdentifier(this.node, this.parent, opts);
+  }
+
+  isReferenced(): boolean {
+    return t.isReferenced(this.node, this.parent);
+  }
+
+  isBlockScoped(): boolean {
+    return t.isBlockScoped(this.node);
+  }
+
+  isVar(): boolean {
+    return t.isVar(this.node);
+  }
+
+  isScope(): boolean {
+    return t.isScope(this.node, this.parent);
+  }
+
+  isTypeGeneric(genericName: string, opts = {}): boolean {
+    var typeInfo = this.getTypeAnnotation();
+    var type     = typeInfo.annotation;
+    if (!type) return false;
+
+    if (type.inferred && opts.inference === false) {
+      return false;
+    }
+
+    if (!t.isGenericTypeAnnotation(type) || !t.isIdentifier(type.id, { name: genericName })) {
+      return false;
+    }
+
+    if (opts.requireTypeParameters && !type.typeParameters) {
+      return false;
+    }
+
+    return true;
+  }
+
+  getBindingIdentifiers() {
+    return t.getBindingIdentifiers(this.node);
+  }
+
+  traverse(opts, state) {
+    traverse(this.node, opts, this.scope, state, this);
+  }
+
+  /**
+   * Match the current node if it matches the provided `pattern`.
+   *
+   * For example, given the match `React.createClass` it would match the
+   * parsed nodes of `React.createClass` and `React["createClass"]`.
+   */
+
+  matchesPattern(pattern: string, allowPartial?: boolean): boolean {
+   var parts = pattern.split(".");
+
+    // not a member expression
+    if (!this.isMemberExpression()) return false;
+
+    var search = [this.node];
+    var i = 0;
+
+    while (search.length) {
+      var node = search.shift();
+
+      if (allowPartial && i === parts.length) {
+        return true;
+      }
+
+      if (t.isIdentifier(node)) {
+        // this part doesn't match
+        if (parts[i] !== node.name) return false;
+      } else if (t.isLiteral(node)) {
+        // this part doesn't match
+        if (parts[i] !== node.value) return false;
+      } else if (t.isMemberExpression(node)) {
+        if (node.computed && !t.isLiteral(node.property)) {
+          // we can't deal with this
+          return false;
+        } else {
+          search.push(node.object);
+          search.push(node.property);
+          continue;
+        }
+      } else {
+        // we can't deal with this
+        return false;
+      }
+
+      // too many parts
+      if (++i > parts.length) {
+        return false;
+      }
+    }
+
+    return true;
+  }
+}
+
+assign(TraversalPath.prototype, require("./evaluation"));
+assign(TraversalPath.prototype, require("./conversion"));
+
+for (var i = 0; i < t.TYPES.length; i++) {
+  let type = t.TYPES[i];
+  let typeKey = `is${type}`;
+  TraversalPath.prototype[typeKey] = function (opts) {
+    return t[typeKey](this.node, opts);
+  };
+}
diff --git a/src/babel/traversal/scope.js b/src/babel/traversal/scope.js
index 5c006703b8..e7f8ea1791 100644
--- a/src/babel/traversal/scope.js
+++ b/src/babel/traversal/scope.js
@@ -2,6 +2,7 @@ import includes from "lodash/collection/includes";
 import traverse from "./index";
 import defaults from "lodash/object/defaults";
 import * as messages from "../messages";
+import Binding from "./binding";
 import globals from "globals";
 import flatten from "lodash/array/flatten";
 import extend from "lodash/object/extend";
@@ -12,27 +13,27 @@ import * as t from "../types";
 var functionVariableVisitor = {
   enter(node, parent, scope, state) {
     if (t.isFor(node)) {
-      each(t.FOR_INIT_KEYS, function (key) {
-        var declar = node[key];
-        if (t.isVar(declar)) state.scope.registerBinding("var", declar);
+      each(t.FOR_INIT_KEYS, (key) => {
+        var declar = this.get(key);
+        if (declar.isVar()) state.scope.registerBinding("var", declar);
       });
     }
 
     // this block is a function so we'll stop since none of the variables
     // declared within are accessible
-    if (t.isFunction(node)) return this.skip();
+    if (this.isFunction()) return this.skip();
 
     // function identifier doesn't belong to this scope
     if (state.blockId && node === state.blockId) return;
 
     // delegate block scope handling to the `blockVariableVisitor`
-    if (t.isBlockScoped(node)) return;
+    if (this.isBlockScoped()) return;
 
     // this will be hit again once we traverse into it after this iteration
-    if (t.isExportDeclaration(node) && t.isDeclaration(node.declaration)) return;
+    if (this.isExportDeclaration() && t.isDeclaration(node.declaration)) return;
 
     // we've ran into a declaration!
-    if (t.isDeclaration(node)) state.scope.registerDeclaration(node);
+    if (this.isDeclaration()) state.scope.registerDeclaration(this);
   }
 };
 
@@ -42,16 +43,20 @@ var programReferenceVisitor = {
       state.addGlobal(node);
     } else if (t.isLabeledStatement(node)) {
       state.addGlobal(node);
-    } else if (t.isAssignmentExpression(node) || t.isUpdateExpression(node) || (t.isUnaryExpression(node) && node.operator === "delete")) {
-      scope.registerBindingReassignment(node);
+    } else if (t.isAssignmentExpression(node)) {
+      scope.registerConstantViolation(this.get("left"), this.get("right"));
+    } else if (t.isUpdateExpression(node)) {
+      scope.registerConstantViolation(this.get("argument"), null);
+    } else if (t.isUnaryExpression(node) && node.operator === "delete") {
+      scope.registerConstantViolation(this.get("left"), null);
     }
   }
 };
 
 var blockVariableVisitor = {
   enter(node, parent, scope, state) {
-    if (t.isFunctionDeclaration(node) || t.isBlockScoped(node)) {
-      state.registerDeclaration(node);
+    if (this.isFunctionDeclaration() || this.isBlockScoped()) {
+      state.registerDeclaration(this);
     } else if (t.isScope(node, parent)) {
       this.skip();
     }
@@ -65,12 +70,20 @@ export default class Scope {
    * within.
    */
 
-  constructor(block: Object, parentBlock: Object, parent?: Scope, file?: File) {
+  constructor(path: TraversalPath, parent?: Scope, file?: File) {
+    var cached = path.getData("scope");
+    if (cached) {
+      return cached;
+    } else {
+      //path.setData("scope", this);
+    }
+
     this.parent = parent;
     this.file   = parent ? parent.file : file;
 
-    this.parentBlock = parentBlock;
-    this.block       = block;
+    this.parentBlock = path.parent;
+    this.block       = path.node;
+    this.path        = path;
 
     this.crawl();
   }
@@ -104,9 +117,7 @@ export default class Scope {
    */
 
   generateUidIdentifier(name: string) {
-    var id = t.identifier(this.generateUid(name));
-    this.getFunctionParent().registerBinding("uid", id);
-    return id;
+    return t.identifier(this.generateUid(name));
   }
 
   /**
@@ -121,7 +132,8 @@ export default class Scope {
     do {
       uid = this._generateUid(name, i);
       i++;
-    } while (this.hasBinding(uid) || this.hasGlobal(uid));
+    } while (this.hasBinding(uid) || this.hasGlobal(uid) || this.hasUid(uid));
+    this.getFunctionParent().uids[uid] = true;
     return uid;
   }
 
@@ -131,6 +143,19 @@ export default class Scope {
     return `_${id}`;
   }
 
+  /**
+   * Description
+   */
+
+  hasUid(name): boolean {
+    var scope = this;
+    do {
+      if (scope.uids[name]) return true;
+      scope = scope.parent;
+    } while (scope);
+    return false;
+  }
+
   /*
    * Description
    */
@@ -209,7 +234,7 @@ export default class Scope {
   rename(oldName: string, newName: string) {
     newName ||= this.generateUidIdentifier(oldName).name;
 
-    var info = this.getBindingInfo(oldName);
+    var info = this.getBinding(oldName);
     if (!info) return;
 
     var binding = info.identifier;
@@ -220,7 +245,7 @@ export default class Scope {
         if (t.isReferencedIdentifier(node, parent) && node.name === oldName) {
           node.name = newName;
         } else if (t.isDeclaration(node)) {
-          var ids = t.getBindingIdentifiers(node);
+          var ids = this.getBindingIdentifiers();
           for (var name in ids) {
             if (name === oldName) ids[name].name = newName;
           }
@@ -238,102 +263,6 @@ export default class Scope {
     binding.name = newName;
   }
 
-  /**
-   * Description
-   */
-
-  inferType(node: Object) {
-    var target;
-
-    if (t.isVariableDeclarator(node)) {
-      target = node.init;
-    }
-
-    if (t.isArrayExpression(target)) {
-      return t.genericTypeAnnotation(t.identifier("Array"));
-    }
-
-    if (t.isObjectExpression(target)) {
-      return;
-    }
-
-    if (t.isLiteral(target)) {
-      return;
-    }
-
-    if (t.isCallExpression(target) && t.isIdentifier(target.callee)) {
-      var funcInfo = this.getBindingInfo(target.callee.name);
-      if (funcInfo) {
-        var funcNode = funcInfo.node;
-        return !funcInfo.reassigned && t.isFunction(funcNode) && node.returnType;
-      }
-    }
-
-    if (t.isIdentifier(target)) {
-      return;
-    }
-  }
-
-  /**
-   * Description
-   */
-
-  isTypeGeneric(name: string, genericName: string) {
-    var info = this.getBindingInfo(name);
-    if (!info) return false;
-
-    var type = info.typeAnnotation;
-    return t.isGenericTypeAnnotation(type) && t.isIdentifier(type.id, { name: genericName });
-  }
-
-  /**
-   * Description
-   */
-
-  assignTypeGeneric(name: string, type: Object) {
-    this.assignType(name, t.genericTypeAnnotation(t.identifier(type)));
-  }
-
-  /**
-   * Description
-   */
-
-  assignType(name: string, type: Object) {
-    var info = this.getBindingInfo(name);
-    if (!info) return;
-
-    info.typeAnnotation = type;
-  }
-
-  /**
-   * Description
-   */
-
-  getTypeAnnotation(id: Object, node: Object): Object {
-    var info = {
-      annotation: null,
-      inferred: false
-    };
-
-    var type;
-
-    if (id.typeAnnotation) {
-      type = id.typeAnnotation;
-    }
-
-    if (!type) {
-      info.inferred = true;
-      type = this.inferType(node);
-    }
-
-    if (type) {
-      if (t.isTypeAnnotation(type)) type = type.typeAnnotation;
-      info.annotation = type;
-    }
-
-    return info;
-  }
-
   /**
    * Description
    */
@@ -341,8 +270,9 @@ export default class Scope {
   toArray(node: Object, i?: number) {
     var file = this.file;
 
-    if (t.isIdentifier(node) && this.isTypeGeneric(node.name, "Array")) {
-      return node;
+    if (t.isIdentifier(node)) {
+      var binding = this.getBinding(node.name);
+      if (binding && binding.isTypeGeneric("Array", { inference: false })) return node;
     }
 
     if (t.isArrayExpression(node)) {
@@ -368,33 +298,21 @@ export default class Scope {
    * Description
    */
 
-  refreshDeclaration(node: Object) {
-    if (t.isBlockScoped(node)) {
-      this.getBlockParent().registerDeclaration(node);
-    } else if (t.isVariableDeclaration(node, { kind: "var" })) {
-      this.getFunctionParent().registerDeclaration(node);
-    } else if (node === this.block) {
-      this.recrawl();
-    }
-  }
-
-  /**
-   * Description
-   */
-
-  registerDeclaration(node: Object) {
+  registerDeclaration(path: TraversalPath) {
+    var node = path.node;
     if (t.isFunctionDeclaration(node)) {
-      this.registerBinding("hoisted", node);
+      this.registerBinding("hoisted", path);
     } else if (t.isVariableDeclaration(node)) {
-      for (var i = 0; i < node.declarations.length; i++) {
-        this.registerBinding(node.kind, node.declarations[i]);
+      var declarations = path.get("declarations");
+      for (var i = 0; i < declarations.length; i++) {
+        this.registerBinding(node.kind, declarations[i]);
       }
     } else if (t.isClassDeclaration(node)) {
-      this.registerBinding("let", node);
+      this.registerBinding("let", path);
     } else if (t.isImportDeclaration(node) || t.isExportDeclaration(node)) {
-      this.registerBinding("module", node);
+      this.registerBinding("module", path);
     } else {
-      this.registerBinding("unknown", node);
+      this.registerBinding("unknown", path);
     }
   }
 
@@ -402,18 +320,16 @@ export default class Scope {
    * Description
    */
 
-  registerBindingReassignment(node: Object) {
-    var ids = t.getBindingIdentifiers(node);
+  registerConstantViolation(left: TraversalPath, right: TraversalPath) {
+    var ids = left.getBindingIdentifiers();
     for (var name in ids) {
-      var info = this.getBindingInfo(name);
-      if (info) {
-        info.reassigned = true;
-
-        if (info.typeAnnotationInferred) {
-          // destroy the inferred typeAnnotation
-          info.typeAnnotation = null;
-        }
+      var binding = this.getBinding(name);
+      if (!binding) continue;
+      if (right) {
+        var rightType = right.typeAnnotation;
+        if (rightType && binding.isCompatibleWithType(rightType)) continue;
       }
+      binding.reassign();
     }
   }
 
@@ -421,27 +337,22 @@ export default class Scope {
    * Description
    */
 
-  registerBinding(kind: string, node: Object) {
+  registerBinding(kind: string, path: TraversalPath) {
     if (!kind) throw new ReferenceError("no `kind`");
 
-    var ids = t.getBindingIdentifiers(node);
+    var ids = path.getBindingIdentifiers();
 
     for (var name in ids) {
       var id = ids[name];
 
       this.checkBlockScopedCollisions(kind, name, id);
 
-      var typeInfo = this.getTypeAnnotation(id, node);
-
-      this.bindings[name] = {
-        typeAnnotationInferred: typeInfo.inferred,
-        typeAnnotation:         typeInfo.annotation,
-        reassigned:             false,
-        identifier:             id,
-        scope:                  this,
-        node:                   node,
-        kind:                   kind
-      };
+      this.bindings[name] = new Binding({
+        identifier: id,
+        scope:      this,
+        path:       path,
+        kind:       kind
+      });
     }
   }
 
@@ -472,7 +383,7 @@ export default class Scope {
    */
 
   recrawl() {
-    this.block._scopeInfo = null;
+    this.path.setData("scopeInfo", null);
     this.crawl();
   }
 
@@ -481,91 +392,88 @@ export default class Scope {
    */
 
   crawl() {
-    var block  = this.block;
-    var i;
+    var path = this.path;
 
     //
 
-    var info = block._scopeInfo;
-    if (info) {
-      extend(this, info);
-      return;
-    }
+    var info = path.getData("scopeInfo");
+    if (info) return extend(this, info);
 
-    info = block._scopeInfo = {
+    info = path.setData("scopeInfo", {
       bindings: object(),
-      globals:  object()
-    };
+      globals:  object(),
+      uids:     object()
+    });
 
     extend(this, info);
 
     // ForStatement - left, init
 
-    if (t.isLoop(block)) {
-      for (i = 0; i < t.FOR_INIT_KEYS.length; i++) {
-        var node = block[t.FOR_INIT_KEYS[i]];
-        if (t.isBlockScoped(node)) this.registerBinding("let", node);
+    if (path.isLoop()) {
+      for (let i = 0; i < t.FOR_INIT_KEYS.length; i++) {
+        var node = path.get(t.FOR_INIT_KEYS[i]);
+        if (node.isBlockScoped()) this.registerBinding("let", node);
       }
 
-      if (t.isBlockStatement(block.body)) {
-        block = block.body;
-      }
+      var body = path.get("body");
+      if (body.isBlockStatement()) path = path.get("body");
     }
 
     // FunctionExpression - id
 
-    if (t.isFunctionExpression(block) && block.id) {
-      if (!t.isProperty(this.parentBlock, { method: true })) {
-        this.registerBinding("var", block.id);
+    if (path.isFunctionExpression() && path.has("id")) {
+      if (!t.isProperty(path.parent, { method: true })) {
+        this.registerBinding("var", path.get("id"));
       }
     }
 
     // Class
 
-    if (t.isClass(block) && block.id) {
-      this.registerBinding("var", block.id);
+    if (path.isClass() && path.has("id")) {
+      this.registerBinding("var", path.get("id"));
     }
 
     // Function - params, rest
 
-    if (t.isFunction(block)) {
-      for (i = 0; i < block.params.length; i++) {
-        this.registerBinding("param", block.params[i]);
+    if (path.isFunction()) {
+      var params = path.get("params");
+      for (let i = 0; i < params.length; i++) {
+        this.registerBinding("param", params[i]);
       }
-      this.traverse(block.body, blockVariableVisitor, this);
+      this.traverse(path.get("body").node, blockVariableVisitor, this);
     }
 
     // Program, BlockStatement, Function - let variables
 
-    if (t.isBlockStatement(block) || t.isProgram(block)) {
-      this.traverse(block, blockVariableVisitor, this);
+    if (path.isBlockStatement() || path.isProgram()) {
+      this.traverse(path.node, blockVariableVisitor, this);
     }
 
     // CatchClause - param
 
-    if (t.isCatchClause(block)) {
-      this.registerBinding("let", block.param);
+    if (path.isCatchClause()) {
+      this.registerBinding("let", path.get("param"));
     }
 
     // ComprehensionExpression - blocks
 
-    if (t.isComprehensionExpression(block)) {
-      this.registerBinding("let", block);
+    if (path.isComprehensionExpression()) {
+      this.registerBinding("let", path);
     }
 
     // Program, Function - var variables
 
-    if (t.isProgram(block) || t.isFunction(block)) {
-      this.traverse(block, functionVariableVisitor, {
-        blockId: block.id,
+    if (path.isProgram() || path.isFunction()) {
+      this.traverse(path.node, functionVariableVisitor, {
+        blockId: path.get("id").node,
         scope:   this
       });
     }
 
     // Program
 
-    if (t.isProgram(block)) {
-      this.traverse(block, programReferenceVisitor, this);
+    if (path.isProgram()) {
+      this.traverse(path.node, programReferenceVisitor, this);
     }
   }
 
@@ -666,7 +574,7 @@ export default class Scope {
    * Description
    */
 
-  getBindingInfo(name: string) {
+  getBinding(name: string) {
     var scope = this;
 
     do {
@@ -688,7 +596,7 @@ export default class Scope {
    */
 
   getBindingIdentifier(name: string) {
-    var info = this.getBindingInfo(name);
+    var info = this.getBinding(name);
     return info && info.identifier;
   }
 
@@ -701,44 +609,6 @@ export default class Scope {
     return binding && binding.identifier;
   }
 
-  /**
-   * Description
-   */
-
-  getOwnImmutableBindingValue(name: string) {
-    return this._immutableBindingInfoToValue(this.getOwnBindingInfo(name));
-  }
-
-  /**
-   * Description
-   */
-
-  getImmutableBindingValue(name: string) {
-    return this._immutableBindingInfoToValue(this.getBindingInfo(name));
-  }
-
-  _immutableBindingInfoToValue(info) {
-    if (!info) return;
-
-    // can't guarantee this value is the same
-    if (info.reassigned) return;
-
-    var node = info.node;
-    if (t.isVariableDeclarator(node)) {
-      if (t.isIdentifier(node.id)) {
-        node = node.init;
-      } else {
-        // otherwise it's probably a destructuring like:
-        // var { foo } = "foo";
-        return;
-      }
-    }
-
-    if (t.isImmutable(node)) {
-      return node;
-    }
-  }
-
   /**
    * Description
    */
@@ -781,7 +651,7 @@ export default class Scope {
    */
 
   removeBinding(name: string) {
-    var info = this.getBindingInfo(name);
+    var info = this.getBinding(name);
     if (info) info.scope.removeOwnBinding(name);
   }
 }
diff --git a/src/babel/types/converters.js b/src/babel/types/converters.js
index ea3a240ff3..429e9c45dd 100644
--- a/src/babel/types/converters.js
+++ b/src/babel/types/converters.js
@@ -10,7 +10,7 @@ import * as t from "./index";
  * Description
  */
 
-export function toComputedKey(node: Object, key: Object = node.key): Object {
+export function toComputedKey(node: Object, key: Object = node.key || node.property): Object {
   if (!node.computed) {
     if (t.isIdentifier(key)) key = t.literal(key.name);
   }
diff --git a/src/babel/types/index.js b/src/babel/types/index.js
index dfbdf9b07e..a82b86cfc3 100644
--- a/src/babel/types/index.js
+++ b/src/babel/types/index.js
@@ -24,15 +24,15 @@ function registerType(type: string, skipAliasCheck?: boolean) {
   };
 }
 
-export var STATEMENT_OR_BLOCK_KEYS = ["consequent", "body", "alternate"];
-export var NATIVE_TYPE_NAMES       = ["Array", "Object", "Number", "Boolean", "Date", "Array", "String"];
-export var FLATTENABLE_KEYS        = ["body", "expressions"];
-export var FOR_INIT_KEYS           = ["left", "init"];
-export var COMMENT_KEYS            = ["leadingComments", "trailingComments"];
+export const STATEMENT_OR_BLOCK_KEYS = ["consequent", "body", "alternate"];
+export const NATIVE_TYPE_NAMES       = ["Array", "Object", "Number", "Boolean", "Date", "Array", "String"];
+export const FLATTENABLE_KEYS        = ["body", "expressions"];
+export const FOR_INIT_KEYS           = ["left", "init"];
+export const COMMENT_KEYS            = ["leadingComments", "trailingComments"];
 
-export var VISITOR_KEYS = require("./visitor-keys");
-export var BUILDER_KEYS = require("./builder-keys");
-export var ALIAS_KEYS   = require("./alias-keys");
+export const VISITOR_KEYS = require("./visitor-keys");
+export const BUILDER_KEYS = require("./builder-keys");
+export const ALIAS_KEYS   = require("./alias-keys");
 
 t.FLIPPED_ALIAS_KEYS = {};
 
@@ -52,7 +52,7 @@ each(t.FLIPPED_ALIAS_KEYS, function (types, type) {
   registerType(type, false);
 });
 
-export var TYPES = Object.keys(t.VISITOR_KEYS).concat(Object.keys(t.FLIPPED_ALIAS_KEYS));
+export const TYPES = Object.keys(t.VISITOR_KEYS).concat(Object.keys(t.FLIPPED_ALIAS_KEYS));
 
 /**
  * Returns whether `node` is of given `type`.
@@ -281,7 +281,6 @@ export function inheritsComments(child: Object, parent: Object): Object {
 
 export function inherits(child: Object, parent: Object): Object {
   child._declarations = parent._declarations;
-  child._scopeInfo    = parent._scopeInfo;
   child.range         = parent.range;
   child.start         = parent.start;
   child.loc           = parent.loc;
@@ -298,7 +297,6 @@ toFastProperties(t);
 toFastProperties(t.VISITOR_KEYS);
 
 exports.__esModule = true;
-assign(t, require("./evaluators"));
 assign(t, require("./retrievers"));
 assign(t, require("./validators"));
 assign(t, require("./converters"));
diff --git a/src/babel/types/visitor-keys.json b/src/babel/types/visitor-keys.json
index e3ad4a629e..b30d9f0106 100644
--- a/src/babel/types/visitor-keys.json
+++ b/src/babel/types/visitor-keys.json
@@ -93,7 +93,7 @@
   "TypeofTypeAnnotation":        ["argument"],
   "TypeAlias":                   ["id", "typeParameters", "right"],
   "TypeAnnotation":              ["typeAnnotation"],
-  "TypeCastExpression":          ["expression"],
+  "TypeCastExpression":          ["expression", "typeAnnotation"],
   "TypeParameterDeclaration":    ["params"],
   "TypeParameterInstantiation":  ["params"],
   "ObjectTypeAnnotation":        ["key", "value"],
diff --git a/src/babel/util.js b/src/babel/util.js
index f9a8184639..d3b271ecc1 100644
--- a/src/babel/util.js
+++ b/src/babel/util.js
@@ -4,6 +4,7 @@ import buildDebug from "debug/node";
 import cloneDeep from "lodash/lang/cloneDeep";
 import isBoolean from "lodash/lang/isBoolean";
 import * as messages from "./messages";
+import minimatch from "minimatch";
 import contains from "lodash/collection/contains";
 import traverse from "./traversal";
 import isString from "lodash/lang/isString";
@@ -43,16 +44,21 @@ export function list(val: string): Array<string> {
 export function regexify(val: any): RegExp {
   if (!val) return new RegExp(/.^/);
   if (Array.isArray(val)) val = val.join("|");
-  if (isString(val)) return new RegExp(val);
+  if (isString(val)) return minimatch.makeRe(val, { nocase: true });
   if (isRegExp(val)) return val;
   throw new TypeError("illegal type for regexify");
 }
 
-export function arrayify(val: any): Array {
+export function arrayify(val: any, mapFn?: Function): Array {
   if (!val) return [];
-  if (isBoolean(val)) return [val];
-  if (isString(val)) return list(val);
-  if (Array.isArray(val)) return val;
+  if (isBoolean(val)) return arrayify([val], mapFn);
+  if (isString(val)) return arrayify(list(val), mapFn);
+
+  if (Array.isArray(val)) {
+    if (mapFn) val = val.map(mapFn);
+    return val;
+  }
+
   throw new TypeError("illegal type for arrayify");
 }
 
diff --git a/test/_transformation-helper.js b/test/_transformation-helper.js
index bcad6fdba8..14f0146983 100644
--- a/test/_transformation-helper.js
+++ b/test/_transformation-helper.js
@@ -55,6 +55,7 @@ var run = function (task, done) {
 
   var getOpts = function (self) {
     return _.merge({
+      suppressDeprecationMessages: true,
       filename: self.loc
     }, opts);
   };
diff --git a/test/fixtures/transformation/es6-block-scoping/hoisting/actual.js b/test/fixtures/transformation/es6-block-scoping/hoisting/actual.js
index 8baf9f54a2..03757cd57d 100644
--- a/test/fixtures/transformation/es6-block-scoping/hoisting/actual.js
+++ b/test/fixtures/transformation/es6-block-scoping/hoisting/actual.js
@@ -1,4 +1,4 @@
-for (let i of [1, 2, 3]) {
+for (let i of nums) {
   var x = 5;
   fns.push(function () {
     return i * x;
diff --git a/test/fixtures/transformation/es6-block-scoping/hoisting/expected.js b/test/fixtures/transformation/es6-block-scoping/hoisting/expected.js
index f8cec2e342..661e28888b 100644
--- a/test/fixtures/transformation/es6-block-scoping/hoisting/expected.js
+++ b/test/fixtures/transformation/es6-block-scoping/hoisting/expected.js
@@ -5,7 +5,7 @@ var _didIteratorError = false;
 var _iteratorError = undefined;
 
 try {
-  for (var _iterator = [1, 2, 3][Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
+  for (var _iterator = nums[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
     var x;
 
     (function () {
@@ -30,4 +30,4 @@ try {
       throw _iteratorError;
     }
   }
-}
\ No newline at end of file
+}
diff --git a/test/fixtures/transformation/es6-modules-amd/exports-variable/expected.js b/test/fixtures/transformation/es6-modules-amd/exports-variable/expected.js
index bd6d12e3f6..b5f5c1538f 100644
--- a/test/fixtures/transformation/es6-modules-amd/exports-variable/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/exports-variable/expected.js
@@ -26,7 +26,9 @@ define(["exports"], function (exports) {
 
   function foo7() {}
 
-  var foo8 = exports.foo8 = function foo8() {
+  var foo8 = function foo8() {
     _classCallCheck(this, foo8);
   };
-});
\ No newline at end of file
+
+  exports.foo8 = foo8;
+});
diff --git a/test/fixtures/transformation/es6-modules-common/exports-variable/expected.js b/test/fixtures/transformation/es6-modules-common/exports-variable/expected.js
index 0b2cbf18e7..b468b9bc5d 100644
--- a/test/fixtures/transformation/es6-modules-common/exports-variable/expected.js
+++ b/test/fixtures/transformation/es6-modules-common/exports-variable/expected.js
@@ -25,6 +25,8 @@ exports.foo6 = foo6;
 
 function foo7() {}
 
-var foo8 = exports.foo8 = function foo8() {
+var foo8 = function foo8() {
   _classCallCheck(this, foo8);
-};
\ No newline at end of file
+};
+
+exports.foo8 = foo8;
diff --git a/test/fixtures/transformation/es6-modules-system/exports-variable/expected.js b/test/fixtures/transformation/es6-modules-system/exports-variable/expected.js
index 8626db3270..5006e12bbf 100644
--- a/test/fixtures/transformation/es6-modules-system/exports-variable/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/exports-variable/expected.js
@@ -34,11 +34,13 @@ System.register([], function (_export) {
 
       _export("foo6", foo6);
 
-      foo8 = _export("foo8", function foo8() {
+      foo8 = function foo8() {
         _classCallCheck(this, foo8);
-      });
+      };
+
+      _export("foo8", foo8);
 
       _export("foo3", foo3 = 5);
     }
   };
-});
\ No newline at end of file
+});
diff --git a/test/fixtures/transformation/es6-modules-umd/exports-variable/expected.js b/test/fixtures/transformation/es6-modules-umd/exports-variable/expected.js
index 49eca85aba..0f1a05c14d 100644
--- a/test/fixtures/transformation/es6-modules-umd/exports-variable/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/exports-variable/expected.js
@@ -32,7 +32,9 @@
 
   function foo7() {}
 
-  var foo8 = exports.foo8 = function foo8() {
+  var foo8 = function foo8() {
     _classCallCheck(this, foo8);
   };
-});
\ No newline at end of file
+
+  exports.foo8 = foo8;
+});
diff --git a/test/fixtures/transformation/es6-spread/known-array/actual.js b/test/fixtures/transformation/es6-spread/known-array/actual.js
deleted file mode 100644
index af3c9258a8..0000000000
--- a/test/fixtures/transformation/es6-spread/known-array/actual.js
+++ /dev/null
@@ -1,2 +0,0 @@
-var arr: Array = bar;
-[...arr];
diff --git a/test/fixtures/transformation/es6-spread/known-array/expected.js b/test/fixtures/transformation/es6-spread/known-array/expected.js
deleted file mode 100644
index cba7214bfd..0000000000
--- a/test/fixtures/transformation/es6-spread/known-array/expected.js
+++ /dev/null
@@ -1,4 +0,0 @@
-"use strict";
-
-var arr = bar;
-[].concat(arr);
diff --git a/test/fixtures/transformation/es7-comprehensions/arguments/actual.js b/test/fixtures/transformation/es7-comprehensions/arguments/actual.js
index 95f9a4df57..5b07664e61 100644
--- a/test/fixtures/transformation/es7-comprehensions/arguments/actual.js
+++ b/test/fixtures/transformation/es7-comprehensions/arguments/actual.js
@@ -1,5 +1,5 @@
 function add() {
-  return [for (i of [1, 2, 3]) i * arguments[0]];
+  return [for (i of nums) i * arguments[0]];
 }
 
 add(5);
diff --git a/test/fixtures/transformation/es7-comprehensions/arguments/expected.js b/test/fixtures/transformation/es7-comprehensions/arguments/expected.js
index 610d5ef84b..ea21a12ae3 100644
--- a/test/fixtures/transformation/es7-comprehensions/arguments/expected.js
+++ b/test/fixtures/transformation/es7-comprehensions/arguments/expected.js
@@ -10,7 +10,7 @@ function add() {
     var _iteratorError = undefined;
 
     try {
-      for (var _iterator = [1, 2, 3][Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
+      for (var _iterator = nums[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
         var i = _step.value;
 
         _ref.push(i * _arguments[0]);
@@ -34,4 +34,4 @@ function add() {
   })();
 }
 
-add(5);
\ No newline at end of file
+add(5);
diff --git a/test/fixtures/transformation/es7-comprehensions/array-expression-single-if/expected.js b/test/fixtures/transformation/es7-comprehensions/array-expression-single-if/expected.js
index e0815299e2..f36d1c6137 100644
--- a/test/fixtures/transformation/es7-comprehensions/array-expression-single-if/expected.js
+++ b/test/fixtures/transformation/es7-comprehensions/array-expression-single-if/expected.js
@@ -2,32 +2,15 @@
 
 var arr = (function () {
   var _arr = [];
-  var _iteratorNormalCompletion = true;
-  var _didIteratorError = false;
-  var _iteratorError = undefined;
+  var _arr2 = [1, 2, 3];
 
-  try {
-    for (var _iterator = [1, 2, 3][Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
-      var i = _step.value;
+  for (var _i = 0; _i < _arr2.length; _i++) {
+    var i = _arr2[_i];
 
-      if (i > 1) {
-        _arr.push(i * i);
-      }
-    }
-  } catch (err) {
-    _didIteratorError = true;
-    _iteratorError = err;
-  } finally {
-    try {
-      if (!_iteratorNormalCompletion && _iterator["return"]) {
-        _iterator["return"]();
-      }
-    } finally {
-      if (_didIteratorError) {
-        throw _iteratorError;
-      }
+    if (i > 1) {
+      _arr.push(i * i);
     }
   }
 
   return _arr;
-})();
\ No newline at end of file
+})();
diff --git a/test/fixtures/transformation/es7-comprehensions/array-expression-single/expected.js b/test/fixtures/transformation/es7-comprehensions/array-expression-single/expected.js
index 2ee858e713..0758f1ede6 100644
--- a/test/fixtures/transformation/es7-comprehensions/array-expression-single/expected.js
+++ b/test/fixtures/transformation/es7-comprehensions/array-expression-single/expected.js
@@ -2,30 +2,13 @@
 
 var arr = (function () {
   var _arr = [];
-  var _iteratorNormalCompletion = true;
-  var _didIteratorError = false;
-  var _iteratorError = undefined;
+  var _arr2 = [1, 2, 3];
 
-  try {
-    for (var _iterator = [1, 2, 3][Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
-      var i = _step.value;
+  for (var _i = 0; _i < _arr2.length; _i++) {
+    var i = _arr2[_i];
 
-      _arr.push(i * i);
-    }
-  } catch (err) {
-    _didIteratorError = true;
-    _iteratorError = err;
-  } finally {
-    try {
-      if (!_iteratorNormalCompletion && _iterator["return"]) {
-        _iterator["return"]();
-      }
-    } finally {
-      if (_didIteratorError) {
-        throw _iteratorError;
-      }
-    }
+    _arr.push(i * i);
   }
 
   return _arr;
-})();
\ No newline at end of file
+})();
diff --git a/test/fixtures/transformation/es7-comprehensions/array-this/actual.js b/test/fixtures/transformation/es7-comprehensions/array-this/actual.js
index 355ed48188..5ae580c2d3 100644
--- a/test/fixtures/transformation/es7-comprehensions/array-this/actual.js
+++ b/test/fixtures/transformation/es7-comprehensions/array-this/actual.js
@@ -1,5 +1,5 @@
 function add() {
-  return [for (i of [1, 2, 3]) i * this.multiplier];
+  return [for (i of nums) i * this.multiplier];
 }
 
 add.call({ multiplier: 5 });
diff --git a/test/fixtures/transformation/es7-comprehensions/array-this/expected.js b/test/fixtures/transformation/es7-comprehensions/array-this/expected.js
index 5f7f52ab97..4ca4eeaee8 100644
--- a/test/fixtures/transformation/es7-comprehensions/array-this/expected.js
+++ b/test/fixtures/transformation/es7-comprehensions/array-this/expected.js
@@ -10,7 +10,7 @@ function add() {
     var _iteratorError = undefined;
 
     try {
-      for (var _iterator = [1, 2, 3][Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
+      for (var _iterator = nums[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
         var i = _step.value;
 
         _ref.push(i * _this.multiplier);
@@ -34,4 +34,4 @@ function add() {
   })();
 }
 
-add.call({ multiplier: 5 });
\ No newline at end of file
+add.call({ multiplier: 5 });
diff --git a/vendor/.babelrc b/vendor/.babelrc
new file mode 100644
index 0000000000..3a8f8eb911
--- /dev/null
+++ b/vendor/.babelrc
@@ -0,0 +1,3 @@
+{
+  "breakConfig": true
+}