diff --git a/.mention-bot b/.mention-bot
index 32b2d0479e72..671103a31cd8 100644
--- a/.mention-bot
+++ b/.mention-bot
@@ -1,5 +1,11 @@
 {
-  "userBlacklist": [ "amasad", "thejameskyle", "jmm", "kittens" ],
+  "userBlacklist": [
+    "amasad",
+    "greenkeeperio-bot",
+    "jmm",
+    "kittens",
+    "thejameskyle"
+   ],
   "fileBlacklist": ["*.md"],
   "skipAlreadyAssignedPR": true,
   "createReviewRequest": true
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7ff3de0e5146..96d28278e150 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,96 @@ _Note: Gaps between patch versions are faulty, broken or test releases._
 
 See [CHANGELOG - 6to5](CHANGELOG-6to5.md) for the pre-4.0.0 version changelog.
 
+## 6.23.0 (2017-02-13)
+
+#### :rocket: New Feature
+* `babel-plugin-transform-react-constant-elements`
+  * [#4812](https://github.com/babel/babel/pull/4812) feature: Support pure expressions in transform-react-constant-elements. ([@STRML](https://github.com/STRML))
+* `babel-preset-flow`, `babel-preset-react`
+  * [#5288](https://github.com/babel/babel/pull/5288) Add new flow preset. ([@thejameskyle](https://github.com/thejameskyle))
+* `babel-traverse`
+  * [#5230](https://github.com/babel/babel/pull/5230) Add path/family sibling traversal methods. ([@chitchu](https://github.com/chitchu))
+* `babel-plugin-transform-es2015-block-scoping`
+  * [#5236](https://github.com/babel/babel/pull/5236) Add option to block-scoping to throw on slow code. ([@spicyj](https://github.com/spicyj))
+
+#### :bug: Bug Fix
+* `babel-core`, `babel-traverse`
+  * [#5050](https://github.com/babel/babel/pull/5050) Rewrite Hub as interface #5047. ([@yongxu](https://github.com/yongxu))
+* `babel-plugin-transform-es2015-for-of`
+  * [#5298](https://github.com/babel/babel/pull/5298) Fix loose for-of with label. ([@jridgewell](https://github.com/jridgewell))
+* `babel-plugin-transform-react-constant-elements`, `babel-traverse`
+  * [#5153](https://github.com/babel/babel/pull/5153) Fix react constant elements bindings. ([@STRML](https://github.com/STRML))
+  * [#5143](https://github.com/babel/babel/pull/5143) Fix PathHoister hoisting JSX member expressions on "this".. ([@STRML](https://github.com/STRML))
+* `babel-plugin-transform-do-expressions`, `babel-traverse`
+  * [#5030](https://github.com/babel/babel/pull/5030) Prevent multiple return statements in a loop when replacing expressions. ([@existentialism](https://github.com/existentialism))
+* `babel-register`
+  * [#5260](https://github.com/babel/babel/pull/5260) Fix TypeError with babel-register's cache. ([@xtuc](https://github.com/xtuc))
+* `babel-traverse`
+  * [#5206](https://github.com/babel/babel/pull/5206) Deopt evaluation of undefined with a local binding. Closes [#5204](https://github.com/babel/babel/issues/5204). ([@boopathi](https://github.com/boopathi))
+* `babel-plugin-transform-runtime`
+  * [#5195](https://github.com/babel/babel/pull/5195) Don't transpile ES7 symbol properties. ([@taion](https://github.com/taion))
+* `babel`
+  * [#5258](https://github.com/babel/babel/pull/5258) checks if babel is installed globally and displays correct cli message. ([@xtina-starr](https://github.com/xtina-starr))
+* `babel-generator`
+  * [#5270](https://github.com/babel/babel/pull/5270) Emit parens for await of ternary expressions. ([@erikdesjardins](https://github.com/erikdesjardins))
+  * [#5193](https://github.com/babel/babel/pull/5193) Fix missing parens when function expressions is tag. ([@existentialism](https://github.com/existentialism))
+* `babel-plugin-transform-es2015-modules-commonjs`
+  * [#5235](https://github.com/babel/babel/pull/5235) Limit export node default assignment stack size #4323. ([@mattste](https://github.com/mattste))
+
+#### :memo: Documentation
+* `babel-*`
+  * [#5244](https://github.com/babel/babel/pull/5244) Normalize options sections in docs [skip ci]. ([@existentialism](https://github.com/existentialism))
+  * [#5216](https://github.com/babel/babel/pull/5216) Remove link to REPL. ([@xtuc](https://github.com/xtuc))
+* Other
+  * [#5242](https://github.com/babel/babel/pull/5242) Add our business model [skip ci]. ([@hzoo](https://github.com/hzoo))
+* `babel-plugin-transform-es2015-spread`
+  * [#5227](https://github.com/babel/babel/pull/5227) Add example to spread README [skip ci]. ([@finkef](https://github.com/finkef))
+* `babel-plugin-transform-flow-strip-types`
+  * [#5212](https://github.com/babel/babel/pull/5212) Remove REPL link transform-flow-strip-types doc. ([@xtuc](https://github.com/xtuc))
+* `babel-plugin-transform-regenerator`
+  * [#5202](https://github.com/babel/babel/pull/5202) Fix transform-regenerator README. ([@xtuc](https://github.com/xtuc))
+* `babel-plugin-transform-es2015-arrow-functions`
+  * [#5200](https://github.com/babel/babel/pull/5200) Fix transform-es2015-arrow-functions code blocks on the website. ([@xtuc](https://github.com/xtuc))
+  * [#5194](https://github.com/babel/babel/pull/5194) Fix transform-es2015-arrow-functions README. ([@xtuc](https://github.com/xtuc))
+
+#### :house: Internal
+* `babel-core`
+  * [#5302](https://github.com/babel/babel/pull/5302) Add charset so tests work with convert-source-map@>1.4. ([@loganfsmyth](https://github.com/loganfsmyth))
+* `babel-core`, `babel-traverse`
+  * [#5050](https://github.com/babel/babel/pull/5050) Rewrite Hub as interface #5047. ([@yongxu](https://github.com/yongxu))
+* `babel-generator`
+  * [#5255](https://github.com/babel/babel/pull/5255) codegen performance: use trim instead of lodash/trimEnd. ([@jwbay](https://github.com/jwbay))
+* `babel-types`
+  * [#5181](https://github.com/babel/babel/pull/5181) Remove uses of lodash/compact. ([@zertosh](https://github.com/zertosh))
+* `babel-*`
+  * [#5265](https://github.com/babel/babel/pull/5265) Re-enable the max-len ESLint rule.. ([@loganfsmyth](https://github.com/loganfsmyth))
+* Other
+  * [#5264](https://github.com/babel/babel/pull/5264) Add a sublime project file. ([@loganfsmyth](https://github.com/loganfsmyth))
+  * [#5182](https://github.com/babel/babel/pull/5182) Run coverage only once. ([@existentialism](https://github.com/existentialism))
+  * [#5165](https://github.com/babel/babel/pull/5165) Add Node 7 to CI. ([@chicoxyzzy](https://github.com/chicoxyzzy))
+
+#### Committers: 20
+- Andres Suarez ([zertosh](https://github.com/zertosh))
+- Ben Alpert ([spicyj](https://github.com/spicyj))
+- Boopathi Rajaa ([boopathi](https://github.com/boopathi))
+- Brian Ng ([existentialism](https://github.com/existentialism))
+- Christina ([xtina-starr](https://github.com/xtina-starr))
+- Erik Desjardins ([erikdesjardins](https://github.com/erikdesjardins))
+- Fabian Finke ([finkef](https://github.com/finkef))
+- Henry Zhu ([hzoo](https://github.com/hzoo))
+- Jimmy Jia ([taion](https://github.com/taion))
+- Justin Ridgewell ([jridgewell](https://github.com/jridgewell))
+- Logan Smyth ([loganfsmyth](https://github.com/loganfsmyth))
+- Matt Stewart ([mattste](https://github.com/mattste))
+- Samuel Reed ([STRML](https://github.com/STRML))
+- Sergey Rubanov ([chicoxyzzy](https://github.com/chicoxyzzy))
+- Sven SAULEAU ([xtuc](https://github.com/xtuc))
+- Vicente Jr Yuchitcho ([chitchu](https://github.com/chitchu))
+- Yongxu Ren ([yongxu](https://github.com/yongxu))
+- [jwbay](https://github.com/jwbay)
+- james kyle ([thejameskyle](https://github.com/thejameskyle))
+- Łukasz Lityński ([hex13](https://github.com/hex13))
+
 ## 6.22.2 (2017-01-19)
 
 #### :bug: Bug Fix
diff --git a/packages/babel-cli/package.json b/packages/babel-cli/package.json
index dba5eea05a4d..f836c0d113d5 100644
--- a/packages/babel-cli/package.json
+++ b/packages/babel-cli/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-cli",
-  "version": "6.22.2",
+  "version": "6.23.0",
   "description": "Babel command line.",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://babeljs.io/",
@@ -16,9 +16,9 @@
     "compiler"
   ],
   "dependencies": {
-    "babel-core": "^6.22.1",
-    "babel-register": "^6.22.0",
-    "babel-polyfill": "^6.22.0",
+    "babel-core": "^6.23.0",
+    "babel-register": "^6.23.0",
+    "babel-polyfill": "^6.23.0",
     "commander": "^2.8.1",
     "convert-source-map": "^1.1.0",
     "fs-readdir-recursive": "^1.0.0",
diff --git a/packages/babel-core/package.json b/packages/babel-core/package.json
index e28bf0b3c70f..4e44376e714f 100644
--- a/packages/babel-core/package.json
+++ b/packages/babel-core/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-core",
-  "version": "6.22.1",
+  "version": "6.23.1",
   "description": "Babel compiler core.",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://babeljs.io/",
@@ -27,13 +27,13 @@
   },
   "dependencies": {
     "babel-code-frame": "^6.22.0",
-    "babel-generator": "^6.22.0",
-    "babel-helpers": "^6.22.0",
-    "babel-messages": "^6.22.0",
-    "babel-template": "^6.22.0",
-    "babel-register": "^6.22.0",
-    "babel-traverse": "^6.22.1",
-    "babel-types": "^6.22.0",
+    "babel-generator": "^6.23.0",
+    "babel-helpers": "^6.23.0",
+    "babel-messages": "^6.23.0",
+    "babel-template": "^6.23.0",
+    "babel-register": "^6.23.0",
+    "babel-traverse": "^6.23.1",
+    "babel-types": "^6.23.0",
     "babylon": "^6.11.0",
     "convert-source-map": "^1.1.0",
     "debug": "^2.1.1",
@@ -46,7 +46,7 @@
   },
   "devDependencies": {
     "babel-helper-fixtures": "^6.22.0",
-    "babel-helper-transform-fixture-test-runner": "^6.22.0",
-    "babel-polyfill": "^6.22.0"
+    "babel-helper-transform-fixture-test-runner": "^6.23.0",
+    "babel-polyfill": "^6.23.0"
   }
 }
diff --git a/packages/babel-core/test/fixtures/transformation/misc/regression-2364/actual.js b/packages/babel-core/test/fixtures/transformation/misc/regression-2364/actual.js
index e995e0d23496..c2ae386b34dd 100644
--- a/packages/babel-core/test/fixtures/transformation/misc/regression-2364/actual.js
+++ b/packages/babel-core/test/fixtures/transformation/misc/regression-2364/actual.js
@@ -1,6 +1,6 @@
 function wrapper(fn) {
   return (...args) => {
-    if (someCondition) {
+    while (someCondition) {
       const val = fn(...args);
       return val.test(() => {
         console.log(val);
diff --git a/packages/babel-core/test/fixtures/transformation/misc/regression-2364/expected.js b/packages/babel-core/test/fixtures/transformation/misc/regression-2364/expected.js
index ae32dbb4d39a..c1079c01cbbf 100644
--- a/packages/babel-core/test/fixtures/transformation/misc/regression-2364/expected.js
+++ b/packages/babel-core/test/fixtures/transformation/misc/regression-2364/expected.js
@@ -2,17 +2,19 @@ function wrapper(fn) {
   return function () {
     var _arguments = arguments;
 
-    if (someCondition) {
-      var _ret = function () {
-        var val = fn(..._arguments);
-        return {
-          v: val.test(function () {
-            console.log(val);
-          })
-        };
-      }();
+    var _loop = function () {
+      var val = fn(..._arguments);
+      return {
+        v: val.test(function () {
+          console.log(val);
+        })
+      };
+    };
+
+    while (someCondition) {
+      var _ret = _loop();
 
       if (typeof _ret === "object") return _ret.v;
     }
   };
-}
\ No newline at end of file
+}
diff --git a/packages/babel-core/test/fixtures/transformation/source-maps/inline/expected.js b/packages/babel-core/test/fixtures/transformation/source-maps/inline/expected.js
index 00ae47b8755d..991056b8bf3a 100644
--- a/packages/babel-core/test/fixtures/transformation/source-maps/inline/expected.js
+++ b/packages/babel-core/test/fixtures/transformation/source-maps/inline/expected.js
@@ -1,4 +1,4 @@
 arr.map(function (x) {
   return x * x;
 });
-//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInNvdXJjZS1tYXBzL2lubGluZS9hY3R1YWwuanMiXSwibmFtZXMiOlsiYXJyIiwibWFwIiwieCJdLCJtYXBwaW5ncyI6IkFBQUFBLElBQUlDLEdBQUosQ0FBUTtBQUFBLFNBQUtDLElBQUlBLENBQVQ7QUFBQSxDQUFSIiwiZmlsZSI6InNvdXJjZS1tYXBzL2lubGluZS9leHBlY3RlZC5qcyIsInNvdXJjZXNDb250ZW50IjpbImFyci5tYXAoeCA9PiB4ICogeCk7Il19
+//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInNvdXJjZS1tYXBzL2lubGluZS9hY3R1YWwuanMiXSwibmFtZXMiOlsiYXJyIiwibWFwIiwieCJdLCJtYXBwaW5ncyI6IkFBQUFBLElBQUlDLEdBQUosQ0FBUTtBQUFBLFNBQUtDLElBQUlBLENBQVQ7QUFBQSxDQUFSIiwiZmlsZSI6InNvdXJjZS1tYXBzL2lubGluZS9leHBlY3RlZC5qcyIsInNvdXJjZXNDb250ZW50IjpbImFyci5tYXAoeCA9PiB4ICogeCk7Il19
diff --git a/packages/babel-generator/package.json b/packages/babel-generator/package.json
index 7e5511e36725..e45347d97446 100644
--- a/packages/babel-generator/package.json
+++ b/packages/babel-generator/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-generator",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Turns an AST into code.",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://babeljs.io/",
@@ -11,9 +11,9 @@
     "lib"
   ],
   "dependencies": {
-    "babel-messages": "^6.22.0",
-    "babel-types": "^6.22.0",
-    "detect-indent": "^5.0.0",
+    "babel-messages": "^6.23.0",
+    "babel-types": "^6.23.0",
+    "detect-indent": "^4.0.0",
     "jsesc": "^1.3.0",
     "lodash": "^4.2.0",
     "source-map": "^0.5.0",
diff --git a/packages/babel-helper-builder-react-jsx/package.json b/packages/babel-helper-builder-react-jsx/package.json
index b42a80759e2f..cbeceb179c0f 100644
--- a/packages/babel-helper-builder-react-jsx/package.json
+++ b/packages/babel-helper-builder-react-jsx/package.json
@@ -1,12 +1,12 @@
 {
   "name": "babel-helper-builder-react-jsx",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Helper function to build react jsx",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-helper-builder-react-jsx",
   "license": "MIT",
   "main": "lib/index.js",
   "dependencies": {
-    "babel-types": "^6.22.0",
+    "babel-types": "^6.23.0",
     "esutils": "^2.0.0",
     "lodash": "^4.2.0"
   }
diff --git a/packages/babel-helper-define-map/package.json b/packages/babel-helper-define-map/package.json
index 6b3757805046..c16bb59384e0 100644
--- a/packages/babel-helper-define-map/package.json
+++ b/packages/babel-helper-define-map/package.json
@@ -1,13 +1,13 @@
 {
   "name": "babel-helper-define-map",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Helper function to define a map",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-helper-define-map",
   "license": "MIT",
   "main": "lib/index.js",
   "dependencies": {
     "lodash": "^4.2.0",
-    "babel-types": "^6.22.0",
-    "babel-helper-function-name": "^6.22.0"
+    "babel-types": "^6.23.0",
+    "babel-helper-function-name": "^6.23.0"
   }
 }
diff --git a/packages/babel-helper-function-name/package.json b/packages/babel-helper-function-name/package.json
index e73131de5d40..62c9f9373f57 100644
--- a/packages/babel-helper-function-name/package.json
+++ b/packages/babel-helper-function-name/package.json
@@ -1,14 +1,14 @@
 {
   "name": "babel-helper-function-name",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Helper function to change the property 'name' of every function",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-helper-function-name",
   "license": "MIT",
   "main": "lib/index.js",
   "dependencies": {
-    "babel-types": "^6.22.0",
-    "babel-traverse": "^6.22.0",
+    "babel-types": "^6.23.0",
+    "babel-traverse": "^6.23.0",
     "babel-helper-get-function-arity": "^6.22.0",
-    "babel-template": "^6.22.0"
+    "babel-template": "^6.23.0"
   }
 }
diff --git a/packages/babel-helper-optimise-call-expression/package.json b/packages/babel-helper-optimise-call-expression/package.json
index b3b8cbdcb467..80e1f3424228 100644
--- a/packages/babel-helper-optimise-call-expression/package.json
+++ b/packages/babel-helper-optimise-call-expression/package.json
@@ -1,11 +1,11 @@
 {
   "name": "babel-helper-optimise-call-expression",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Helper function to optimise call expression",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-helper-optimise-call-expression",
   "license": "MIT",
   "main": "lib/index.js",
   "dependencies": {
-    "babel-types": "^6.22.0"
+    "babel-types": "^6.23.0"
   }
 }
diff --git a/packages/babel-helper-replace-supers/package.json b/packages/babel-helper-replace-supers/package.json
index d1bb2832095b..24edb8200270 100644
--- a/packages/babel-helper-replace-supers/package.json
+++ b/packages/babel-helper-replace-supers/package.json
@@ -1,15 +1,15 @@
 {
   "name": "babel-helper-replace-supers",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Helper function to replace supers",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-helper-replace-supers",
   "license": "MIT",
   "main": "lib/index.js",
   "dependencies": {
-    "babel-helper-optimise-call-expression": "^6.22.0",
-    "babel-traverse": "^6.22.0",
-    "babel-messages": "^6.22.0",
-    "babel-template": "^6.22.0",
-    "babel-types": "^6.22.0"
+    "babel-helper-optimise-call-expression": "^6.23.0",
+    "babel-traverse": "^6.23.0",
+    "babel-messages": "^6.23.0",
+    "babel-template": "^6.23.0",
+    "babel-types": "^6.23.0"
   }
 }
diff --git a/packages/babel-helper-transform-fixture-test-runner/package.json b/packages/babel-helper-transform-fixture-test-runner/package.json
index 2d9f78097a93..f5c03762893e 100644
--- a/packages/babel-helper-transform-fixture-test-runner/package.json
+++ b/packages/babel-helper-transform-fixture-test-runner/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-helper-transform-fixture-test-runner",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Transform test runner for babel-helper-fixtures module",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://babeljs.io/",
@@ -8,8 +8,8 @@
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-helper-transform-fixture-test-runner",
   "main": "lib/index.js",
   "dependencies": {
-    "babel-core": "^6.22.0",
-    "babel-polyfill": "^6.22.0",
+    "babel-core": "^6.23.0",
+    "babel-polyfill": "^6.23.0",
     "babel-helper-fixtures": "^6.22.0",
     "source-map": "^0.5.0",
     "babel-code-frame": "^6.22.0",
diff --git a/packages/babel-helpers/package.json b/packages/babel-helpers/package.json
index 19e03ccd865d..bc88144c05e4 100644
--- a/packages/babel-helpers/package.json
+++ b/packages/babel-helpers/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-helpers",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Collection of helper functions used by Babel transforms.",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://babeljs.io/",
@@ -8,6 +8,6 @@
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-helpers",
   "main": "lib/index.js",
   "dependencies": {
-    "babel-template": "^6.22.0"
+    "babel-template": "^6.23.0"
   }
 }
diff --git a/packages/babel-messages/package.json b/packages/babel-messages/package.json
index 022d7508ac37..177efb0499df 100644
--- a/packages/babel-messages/package.json
+++ b/packages/babel-messages/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-messages",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Collection of debug messages used by Babel.",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://babeljs.io/",
diff --git a/packages/babel-plugin-transform-class-properties/package.json b/packages/babel-plugin-transform-class-properties/package.json
index 7122b69b1065..8f0b3d74cd28 100644
--- a/packages/babel-plugin-transform-class-properties/package.json
+++ b/packages/babel-plugin-transform-class-properties/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-plugin-transform-class-properties",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "This plugin transforms static class properties as well as properties declared with the property initializer syntax",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-class-properties",
   "license": "MIT",
@@ -9,9 +9,9 @@
     "babel-plugin"
   ],
   "dependencies": {
-    "babel-helper-function-name": "^6.22.0",
+    "babel-helper-function-name": "^6.23.0",
     "babel-plugin-syntax-class-properties": "^6.8.0",
-    "babel-template": "^6.22.0"
+    "babel-template": "^6.23.0"
   },
   "devDependencies": {
     "babel-helper-plugin-test-runner": "^6.22.0"
diff --git a/packages/babel-plugin-transform-es2015-block-scoping/package.json b/packages/babel-plugin-transform-es2015-block-scoping/package.json
index ef72fdfecf2b..569706fca18c 100644
--- a/packages/babel-plugin-transform-es2015-block-scoping/package.json
+++ b/packages/babel-plugin-transform-es2015-block-scoping/package.json
@@ -1,14 +1,14 @@
 {
   "name": "babel-plugin-transform-es2015-block-scoping",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Compile ES2015 block scoping (const and let) to ES5",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-es2015-block-scoping",
   "license": "MIT",
   "main": "lib/index.js",
   "dependencies": {
-    "babel-traverse": "^6.22.0",
-    "babel-types": "^6.22.0",
-    "babel-template": "^6.22.0",
+    "babel-traverse": "^6.23.0",
+    "babel-types": "^6.23.0",
+    "babel-template": "^6.23.0",
     "lodash": "^4.2.0"
   },
   "keywords": [
diff --git a/packages/babel-plugin-transform-es2015-block-scoping/src/index.js b/packages/babel-plugin-transform-es2015-block-scoping/src/index.js
index b1227d3a52c0..f63305462297 100644
--- a/packages/babel-plugin-transform-es2015-block-scoping/src/index.js
+++ b/packages/babel-plugin-transform-es2015-block-scoping/src/index.js
@@ -112,8 +112,21 @@ function isVar(node) {
 }
 
 const letReferenceBlockVisitor = traverse.visitors.merge([{
+  Loop: {
+    enter(path, state) {
+      state.loopDepth++;
+    },
+    exit(path, state) {
+      state.loopDepth--;
+    },
+  },
   Function(path, state) {
-    path.traverse(letReferenceFunctionVisitor, state);
+    // References to block-scoped variables only require added closures if it's
+    // possible for the code to run more than once -- otherwise it is safe to
+    // simply rename the variables.
+    if (state.loopDepth > 0) {
+      path.traverse(letReferenceFunctionVisitor, state);
+    }
     return path.skip();
   }
 }, tdzVisitor]);
@@ -549,9 +562,19 @@ class BlockScoping {
     const state = {
       letReferences: this.letReferences,
       closurify:     false,
-      file:          this.file
+      file:          this.file,
+      loopDepth:     0,
     };
 
+    const loopOrFunctionParent = this.blockPath.find(
+      (path) => path.isLoop() || path.isFunction()
+    );
+    if (loopOrFunctionParent && loopOrFunctionParent.isLoop()) {
+      // There is a loop ancestor closer than the closest function, so we
+      // consider ourselves to be in a loop.
+      state.loopDepth++;
+    }
+
     // traverse through this block, stopping on functions and checking if they
     // contain any local let references
     this.blockPath.traverse(letReferenceBlockVisitor, state);
diff --git a/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/issue-2174/expected.js b/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/issue-2174/expected.js
index 1dce9c4c174c..9efbc1091f2b 100644
--- a/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/issue-2174/expected.js
+++ b/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/issue-2174/expected.js
@@ -1,11 +1,9 @@
 if (true) {
-  var x;
+  var foo = function () {};
 
-  (function () {
-    function foo() {}
-    function bar() {
-      return foo;
-    }
-    for (x in {}) {}
-  })();
+  var bar = function () {
+    return foo;
+  };
+
+  for (var x in {}) {}
 }
diff --git a/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/loops-and-no-loops/actual.js b/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/loops-and-no-loops/actual.js
new file mode 100644
index 000000000000..f030ac811de4
--- /dev/null
+++ b/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/loops-and-no-loops/actual.js
@@ -0,0 +1,34 @@
+function foo() {
+  const x = 5;
+  console.log(x);
+
+  {
+    const x = 7;
+    setTimeout(() => x, 0);
+  }
+}
+
+function bar() {
+  const x = 5;
+  console.log(x);
+
+  for (let i = 0; i < 7; i++) {
+    {
+      const x = i;
+      setTimeout(() => x, 0);
+    }
+  }
+}
+
+function baz() {
+  const x = 5;
+  console.log(x);
+
+  for (let i = 0; i < 7; i++) {
+    var qux = function qux(y) {
+      const x = y;
+      setTimeout(() => x, 0);
+    };
+    qux(i);
+  }
+}
diff --git a/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/loops-and-no-loops/expected.js b/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/loops-and-no-loops/expected.js
new file mode 100644
index 000000000000..a86a2e481147
--- /dev/null
+++ b/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/loops-and-no-loops/expected.js
@@ -0,0 +1,42 @@
+function foo() {
+  var x = 5;
+  console.log(x);
+
+  {
+    var _x = 7;
+    setTimeout(function () {
+      return _x;
+    }, 0);
+  }
+}
+
+function bar() {
+  var x = 5;
+  console.log(x);
+
+  for (var i = 0; i < 7; i++) {
+    {
+      (function () {
+        var x = i;
+        setTimeout(function () {
+          return x;
+        }, 0);
+      })();
+    }
+  }
+}
+
+function baz() {
+  var x = 5;
+  console.log(x);
+
+  for (var i = 0; i < 7; i++) {
+    var qux = function qux(y) {
+      var x = y;
+      setTimeout(function () {
+        return x;
+      }, 0);
+    };
+    qux(i);
+  }
+}
diff --git a/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/sibling-scopes/actual.js b/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/sibling-scopes/actual.js
new file mode 100644
index 000000000000..e3020dada7f6
--- /dev/null
+++ b/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/sibling-scopes/actual.js
@@ -0,0 +1,11 @@
+var f1, f2;
+{
+  let z = 'z1 value';
+  f1 = function() { return z; };
+}
+{
+  let z = 'z2 value';
+  f2 = function() { return z; };
+}
+f1();
+f2();
diff --git a/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/sibling-scopes/expected.js b/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/sibling-scopes/expected.js
new file mode 100644
index 000000000000..8bbdfc7ddff4
--- /dev/null
+++ b/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/sibling-scopes/expected.js
@@ -0,0 +1,15 @@
+var f1, f2;
+{
+  var z = 'z1 value';
+  f1 = function () {
+    return z;
+  };
+}
+{
+  var _z = 'z2 value';
+  f2 = function () {
+    return _z;
+  };
+}
+f1();
+f2();
\ No newline at end of file
diff --git a/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/superswitch/actual.js b/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/superswitch/actual.js
index 857b8641f415..5dedf9a59244 100644
--- a/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/superswitch/actual.js
+++ b/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/superswitch/actual.js
@@ -1,16 +1,18 @@
 function foo() {
-  switch (2) {
-    case 0: {
-      if (true) {
-        return;
-      }
+  while (true) {
+    switch (2) {
+      case 0: {
+        if (true) {
+          return;
+        }
 
-      const stuff = new Map();
-      const data = 0;
-      stuff.forEach(() => {
-        const d = data;
-      });
-      break;
+        const stuff = new Map();
+        const data = 0;
+        stuff.forEach(() => {
+          const d = data;
+        });
+        break;
+      }
     }
   }
 }
diff --git a/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/superswitch/expected.js b/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/superswitch/expected.js
index 05d7afe3d96c..80b21eba9cdc 100644
--- a/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/superswitch/expected.js
+++ b/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/superswitch/expected.js
@@ -1,29 +1,31 @@
 function foo() {
-  switch (2) {
-    case 0:
-      {
-        var _ret = function () {
-          if (true) {
-            return {
-              v: void 0
-            };
-          }
+  while (true) {
+    switch (2) {
+      case 0:
+        {
+          var _ret = function () {
+            if (true) {
+              return {
+                v: void 0
+              };
+            }
 
-          var stuff = new Map();
-          var data = 0;
-          stuff.forEach(function () {
-            var d = data;
-          });
-          return "break";
-        }();
+            var stuff = new Map();
+            var data = 0;
+            stuff.forEach(function () {
+              var d = data;
+            });
+            return "break";
+          }();
 
-        switch (_ret) {
-          case "break":
-            break;
+          switch (_ret) {
+            case "break":
+              break;
 
-          default:
-            if (typeof _ret === "object") return _ret.v;
+            default:
+              if (typeof _ret === "object") return _ret.v;
+          }
         }
-      }
+    }
   }
 }
diff --git a/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/switch-callbacks/actual.js b/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/switch-callbacks/actual.js
index c57bdc6e5150..99f8726f058a 100644
--- a/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/switch-callbacks/actual.js
+++ b/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/switch-callbacks/actual.js
@@ -1,10 +1,12 @@
 function fn() {
-    switch (true) {
-    default:
-        let foo = 4;
-        if (true) {
-            let bar = () => foo;
-            console.log(bar());
+    while (true) {
+        switch (true) {
+        default:
+            let foo = 4;
+            if (true) {
+                let bar = () => foo;
+                console.log(bar());
+            }
         }
     }
 }
diff --git a/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/switch-callbacks/expected.js b/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/switch-callbacks/expected.js
index 2efd145af333..40f23daea608 100644
--- a/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/switch-callbacks/expected.js
+++ b/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/switch-callbacks/expected.js
@@ -1,14 +1,16 @@
 function fn() {
-    (function () {
-        switch (true) {
-            default:
-                var foo = 4;
-                if (true) {
-                    var bar = function () {
-                        return foo;
-                    };
-                    console.log(bar());
-                }
-        }
-    })();
+    while (true) {
+        (function () {
+            switch (true) {
+                default:
+                    var foo = 4;
+                    if (true) {
+                        var bar = function () {
+                            return foo;
+                        };
+                        console.log(bar());
+                    }
+            }
+        })();
+    }
 }
diff --git a/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/throwIfClosureRequired/for-const-closure/expected.js b/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/throwIfClosureRequired/for-const-closure/expected.js
new file mode 100644
index 000000000000..c28cb3bf748e
--- /dev/null
+++ b/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/throwIfClosureRequired/for-const-closure/expected.js
@@ -0,0 +1,6 @@
+for (var i = 0; i < 5; i++) {
+  var l = i;
+  setTimeout(function () {
+    console.log(l);
+  }, 1);
+}
\ No newline at end of file
diff --git a/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/throwIfClosureRequired/superswitch/actual.js b/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/throwIfClosureRequired/superswitch/actual.js
deleted file mode 100644
index 857b8641f415..000000000000
--- a/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/throwIfClosureRequired/superswitch/actual.js
+++ /dev/null
@@ -1,16 +0,0 @@
-function foo() {
-  switch (2) {
-    case 0: {
-      if (true) {
-        return;
-      }
-
-      const stuff = new Map();
-      const data = 0;
-      stuff.forEach(() => {
-        const d = data;
-      });
-      break;
-    }
-  }
-}
diff --git a/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/throwIfClosureRequired/superswitch/options.json b/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/throwIfClosureRequired/superswitch/options.json
deleted file mode 100644
index d210fdebfc97..000000000000
--- a/packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/throwIfClosureRequired/superswitch/options.json
+++ /dev/null
@@ -1,3 +0,0 @@
-{
-  "throws": "Compiling let/const in this block would add a closure (throwIfClosureRequired)."
-}
diff --git a/packages/babel-plugin-transform-es2015-classes/package.json b/packages/babel-plugin-transform-es2015-classes/package.json
index 1d17d0b74835..cd552e395d28 100644
--- a/packages/babel-plugin-transform-es2015-classes/package.json
+++ b/packages/babel-plugin-transform-es2015-classes/package.json
@@ -1,19 +1,19 @@
 {
   "name": "babel-plugin-transform-es2015-classes",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Compile ES2015 classes to ES5",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-es2015-classes",
   "license": "MIT",
   "main": "lib/index.js",
   "dependencies": {
-    "babel-helper-optimise-call-expression": "^6.22.0",
-    "babel-helper-function-name": "^6.22.0",
-    "babel-helper-replace-supers": "^6.22.0",
-    "babel-template": "^6.22.0",
-    "babel-traverse": "^6.22.0",
-    "babel-helper-define-map": "^6.22.0",
-    "babel-messages": "^6.22.0",
-    "babel-types": "^6.22.0"
+    "babel-helper-optimise-call-expression": "^6.23.0",
+    "babel-helper-function-name": "^6.23.0",
+    "babel-helper-replace-supers": "^6.23.0",
+    "babel-template": "^6.23.0",
+    "babel-traverse": "^6.23.0",
+    "babel-helper-define-map": "^6.23.0",
+    "babel-messages": "^6.23.0",
+    "babel-types": "^6.23.0"
   },
   "keywords": [
     "babel-plugin"
diff --git a/packages/babel-plugin-transform-es2015-destructuring/package.json b/packages/babel-plugin-transform-es2015-destructuring/package.json
index 4eb5eb75aee5..53b5174965fd 100644
--- a/packages/babel-plugin-transform-es2015-destructuring/package.json
+++ b/packages/babel-plugin-transform-es2015-destructuring/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-plugin-transform-es2015-destructuring",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Compile ES2015 destructuring to ES5",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-es2015-destructuring",
   "license": "MIT",
diff --git a/packages/babel-plugin-transform-es2015-for-of/package.json b/packages/babel-plugin-transform-es2015-for-of/package.json
index 53b2959969f4..99c92140bf8f 100644
--- a/packages/babel-plugin-transform-es2015-for-of/package.json
+++ b/packages/babel-plugin-transform-es2015-for-of/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-plugin-transform-es2015-for-of",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Compile ES2015 for...of to ES5",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-es2015-for-of",
   "license": "MIT",
diff --git a/packages/babel-plugin-transform-es2015-for-of/src/index.js b/packages/babel-plugin-transform-es2015-for-of/src/index.js
index 958eae6bce1b..b0b3a6bcbffc 100644
--- a/packages/babel-plugin-transform-es2015-for-of/src/index.js
+++ b/packages/babel-plugin-transform-es2015-for-of/src/index.js
@@ -135,9 +135,8 @@ export default function ({ messages, template, types: t }) {
   };
 
   function loose(path, file) {
-    const { node, scope } = path;
-
-    const left = node.left;
+    const { node, scope, parent } = path;
+    const { left } = node;
     let declar, id;
 
     if (t.isIdentifier(left) || t.isPattern(left) || t.isMemberExpression(left)) {
@@ -171,11 +170,18 @@ export default function ({ messages, template, types: t }) {
     }
 
     //
+    const isLabeledParent = t.isLabeledStatement(parent);
+    let labeled;
+
+    if (isLabeledParent) {
+      labeled = t.labeledStatement(parent.label, loop);
+    }
 
     return {
-      declar: declar,
-      node:   loop,
-      loop:   loop
+      replaceParent: isLabeledParent,
+      declar:        declar,
+      node:          labeled || loop,
+      loop:          loop
     };
   }
 
diff --git a/packages/babel-plugin-transform-es2015-for-of/test/fixtures/loose/nested-label-for-of/actual.js b/packages/babel-plugin-transform-es2015-for-of/test/fixtures/loose/nested-label-for-of/actual.js
new file mode 100644
index 000000000000..73c8203449d4
--- /dev/null
+++ b/packages/babel-plugin-transform-es2015-for-of/test/fixtures/loose/nested-label-for-of/actual.js
@@ -0,0 +1,5 @@
+b: for (let c of d()) {
+  for (let e of f()) {
+    continue b;
+  }
+}
diff --git a/packages/babel-plugin-transform-es2015-for-of/test/fixtures/loose/nested-label-for-of/expected.js b/packages/babel-plugin-transform-es2015-for-of/test/fixtures/loose/nested-label-for-of/expected.js
new file mode 100644
index 000000000000..e3e9396649ef
--- /dev/null
+++ b/packages/babel-plugin-transform-es2015-for-of/test/fixtures/loose/nested-label-for-of/expected.js
@@ -0,0 +1,31 @@
+b: for (var _iterator = d(), _isArray = Array.isArray(_iterator), _i = 0, _iterator = _isArray ? _iterator : _iterator[Symbol.iterator]();;) {
+  var _ref;
+
+  if (_isArray) {
+    if (_i >= _iterator.length) break;
+    _ref = _iterator[_i++];
+  } else {
+    _i = _iterator.next();
+    if (_i.done) break;
+    _ref = _i.value;
+  }
+
+  let c = _ref;
+
+  for (var _iterator2 = f(), _isArray2 = Array.isArray(_iterator2), _i2 = 0, _iterator2 = _isArray2 ? _iterator2 : _iterator2[Symbol.iterator]();;) {
+    var _ref2;
+
+    if (_isArray2) {
+      if (_i2 >= _iterator2.length) break;
+      _ref2 = _iterator2[_i2++];
+    } else {
+      _i2 = _iterator2.next();
+      if (_i2.done) break;
+      _ref2 = _i2.value;
+    }
+
+    let e = _ref2;
+
+    continue b;
+  }
+}
diff --git a/packages/babel-plugin-transform-es2015-modules-commonjs/package.json b/packages/babel-plugin-transform-es2015-modules-commonjs/package.json
index 923bf06419bf..47cca38a41d6 100644
--- a/packages/babel-plugin-transform-es2015-modules-commonjs/package.json
+++ b/packages/babel-plugin-transform-es2015-modules-commonjs/package.json
@@ -1,13 +1,13 @@
 {
   "name": "babel-plugin-transform-es2015-modules-commonjs",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "This plugin transforms ES2015 modules to CommonJS",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-es2015-modules-commonjs",
   "license": "MIT",
   "main": "lib/index.js",
   "dependencies": {
-    "babel-types": "^6.22.0",
-    "babel-template": "^6.22.0",
+    "babel-types": "^6.23.0",
+    "babel-template": "^6.23.0",
     "babel-plugin-transform-strict-mode": "^6.22.0"
   },
   "keywords": [
diff --git a/packages/babel-plugin-transform-es2015-modules-systemjs/package.json b/packages/babel-plugin-transform-es2015-modules-systemjs/package.json
index 73cdf2d9c589..4d6e0841fbe0 100644
--- a/packages/babel-plugin-transform-es2015-modules-systemjs/package.json
+++ b/packages/babel-plugin-transform-es2015-modules-systemjs/package.json
@@ -1,12 +1,12 @@
 {
   "name": "babel-plugin-transform-es2015-modules-systemjs",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "This plugin transforms ES2015 modules to SystemJS",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-es2015-modules-systemjs",
   "license": "MIT",
   "main": "lib/index.js",
   "dependencies": {
-    "babel-template": "^6.22.0",
+    "babel-template": "^6.23.0",
     "babel-helper-hoist-variables": "^6.22.0"
   },
   "keywords": [
diff --git a/packages/babel-plugin-transform-es2015-modules-umd/package.json b/packages/babel-plugin-transform-es2015-modules-umd/package.json
index 95944f163b55..d4a5a0e71d8b 100644
--- a/packages/babel-plugin-transform-es2015-modules-umd/package.json
+++ b/packages/babel-plugin-transform-es2015-modules-umd/package.json
@@ -1,13 +1,13 @@
 {
   "name": "babel-plugin-transform-es2015-modules-umd",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "This plugin transforms ES2015 modules to UMD",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-es2015-modules-umd",
   "license": "MIT",
   "main": "lib/index.js",
   "dependencies": {
     "babel-plugin-transform-es2015-modules-amd": "^6.22.0",
-    "babel-template": "^6.22.0"
+    "babel-template": "^6.23.0"
   },
   "keywords": [
     "babel-plugin"
diff --git a/packages/babel-plugin-transform-es2015-parameters/package.json b/packages/babel-plugin-transform-es2015-parameters/package.json
index 72fdeee2a421..1dec6ec1515d 100644
--- a/packages/babel-plugin-transform-es2015-parameters/package.json
+++ b/packages/babel-plugin-transform-es2015-parameters/package.json
@@ -1,16 +1,16 @@
 {
   "name": "babel-plugin-transform-es2015-parameters",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Compile ES2015 default and rest parameters to ES5",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-es2015-parameters",
   "license": "MIT",
   "main": "lib/index.js",
   "dependencies": {
-    "babel-traverse": "^6.22.0",
+    "babel-traverse": "^6.23.0",
     "babel-helper-call-delegate": "^6.22.0",
     "babel-helper-get-function-arity": "^6.22.0",
-    "babel-template": "^6.22.0",
-    "babel-types": "^6.22.0"
+    "babel-template": "^6.23.0",
+    "babel-types": "^6.23.0"
   },
   "keywords": [
     "babel-plugin"
diff --git a/packages/babel-plugin-transform-es2015-typeof-symbol/package.json b/packages/babel-plugin-transform-es2015-typeof-symbol/package.json
index 323c189e9345..75fb73930ea1 100644
--- a/packages/babel-plugin-transform-es2015-typeof-symbol/package.json
+++ b/packages/babel-plugin-transform-es2015-typeof-symbol/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-plugin-transform-es2015-typeof-symbol",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "This transformer wraps all typeof expressions with a method that replicates native behaviour. (ie. returning “symbol” for symbols)",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-es2015-typeof-symbol",
   "license": "MIT",
diff --git a/packages/babel-plugin-transform-object-rest-spread/package.json b/packages/babel-plugin-transform-object-rest-spread/package.json
index b3686266c18a..d4bdce78b56a 100644
--- a/packages/babel-plugin-transform-object-rest-spread/package.json
+++ b/packages/babel-plugin-transform-object-rest-spread/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-plugin-transform-object-rest-spread",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Compile object rest and spread to ES5",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-object-rest-spread",
   "license": "MIT",
diff --git a/packages/babel-plugin-transform-proto-to-assign/package.json b/packages/babel-plugin-transform-proto-to-assign/package.json
index b0eb2e46e11c..8817ae36f6e4 100644
--- a/packages/babel-plugin-transform-proto-to-assign/package.json
+++ b/packages/babel-plugin-transform-proto-to-assign/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-plugin-transform-proto-to-assign",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Babel plugin for turning __proto__ into a shallow property clone",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-proto-to-assign",
   "license": "MIT",
diff --git a/packages/babel-plugin-transform-react-constant-elements/package.json b/packages/babel-plugin-transform-react-constant-elements/package.json
index 79d30ac76273..77c911d9a775 100644
--- a/packages/babel-plugin-transform-react-constant-elements/package.json
+++ b/packages/babel-plugin-transform-react-constant-elements/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-plugin-transform-react-constant-elements",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Treat React JSX elements as value types and hoist them to the highest scope",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-react-constant-elements",
   "license": "MIT",
diff --git a/packages/babel-plugin-transform-react-constant-elements/src/index.js b/packages/babel-plugin-transform-react-constant-elements/src/index.js
index a25fb67e6c6d..b38f2008d154 100644
--- a/packages/babel-plugin-transform-react-constant-elements/src/index.js
+++ b/packages/babel-plugin-transform-react-constant-elements/src/index.js
@@ -1,4 +1,4 @@
-export default function () {
+export default function ({ types: t }) {
   const immutabilityVisitor = {
     enter(path, state) {
       const stop = () => {
@@ -11,15 +11,39 @@ export default function () {
         return;
       }
 
+      // Elements with refs are not safe to hoist.
       if (path.isJSXIdentifier({ name: "ref" }) && path.parentPath.isJSXAttribute({ name: path.node })) {
         return stop();
       }
 
+      // Ignore identifiers & JSX expressions.
       if (path.isJSXIdentifier() || path.isIdentifier() || path.isJSXMemberExpression()) {
         return;
       }
 
-      if (!path.isImmutable()) stop();
+      if (!path.isImmutable()) {
+        // If it's not immutable, it may still be a pure expression, such as string concatenation.
+        // It is still safe to hoist that, so long as its result is immutable.
+        // If not, it is not safe to replace as mutable values (like objects) could be mutated after render.
+        // https://github.com/facebook/react/issues/3226
+        if (path.isPure()) {
+          const expressionResult = path.evaluate();
+          if (expressionResult.confident) {
+            // We know the result; check its mutability.
+            const { value } = expressionResult;
+            const isMutable = (value && typeof value === "object") || (typeof value === "function");
+            if (!isMutable) {
+              // It evaluated to an immutable value, so we can hoist it.
+              return;
+            }
+          } else if (t.isIdentifier(expressionResult.deopt)) {
+            // It's safe to hoist here if the deopt reason is an identifier (e.g. func param).
+            // The hoister will take care of how high up it can be hoisted.
+            return;
+          }
+        }
+        stop();
+      }
     }
   };
 
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/append-to-end-when-declared-in-scope-3/expected.js b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/append-to-end-when-declared-in-scope-3/expected.js
index cceca3a5e883..46849febf69f 100644
--- a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/append-to-end-when-declared-in-scope-3/expected.js
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/append-to-end-when-declared-in-scope-3/expected.js
@@ -1,18 +1,19 @@
-var _ref = <p>Parent</p>;
-
 var _ref2 = <div>child</div>;
 
+var _ref3 = <p>Parent</p>;
+
 (function () {
   class App extends React.Component {
     render() {
-      return <div>
-          {_ref}
-          <AppItem />
-        </div>;
+      return _ref;
     }
   }
 
   const AppItem = () => {
     return _ref2;
-  };
-});
+  },
+        _ref = <div>
+          {_ref3}
+          <AppItem />
+        </div>;
+});
\ No newline at end of file
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/append-to-end-when-declared-in-scope/expected.js b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/append-to-end-when-declared-in-scope/expected.js
index 5fc826084567..fe04d4853fea 100644
--- a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/append-to-end-when-declared-in-scope/expected.js
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/append-to-end-when-declared-in-scope/expected.js
@@ -1,16 +1,14 @@
-var _ref = <p>Parent</p>;
-
 export default class App extends React.Component {
   render() {
-    return <div>
-        {_ref}
-        <AppItem />
-      </div>;
+    return _ref;
   }
 }
 
-var _ref2 = <div>child</div>;
-
-const AppItem = () => {
+const _ref2 = <div>child</div>,
+      AppItem = () => {
   return _ref2;
-};
+},
+      _ref = <div>
+        <p>Parent</p>
+        <AppItem />
+      </div>;
\ No newline at end of file
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-before-class/actual.js b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-before-class/actual.js
new file mode 100644
index 000000000000..0bcdd9ef7c39
--- /dev/null
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-before-class/actual.js
@@ -0,0 +1,15 @@
+import React from "react";
+
+const Parent = ({}) => (
+  <div className="parent">
+    <Child/>
+  </div>
+);
+
+export default Parent;
+
+let Child = () => (
+  <div className="child">
+    ChildTextContent
+  </div>
+);
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-before-class/expected.js b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-before-class/expected.js
new file mode 100644
index 000000000000..6bcd6e0ffbd8
--- /dev/null
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-before-class/expected.js
@@ -0,0 +1,13 @@
+import React from "react";
+
+const Parent = ({}) => _ref;
+
+export default Parent;
+
+let _ref2 = <div className="child">
+    ChildTextContent
+  </div>,
+    Child = () => _ref2,
+    _ref = <div className="parent">
+    <Child />
+  </div>;
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-before-declaration/expected.js b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-before-declaration/expected.js
index d85f9f3244c6..45b91bd2961c 100644
--- a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-before-declaration/expected.js
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-before-declaration/expected.js
@@ -8,8 +8,9 @@ function render() {
 
 function render() {
   const bar = "bar",
-        renderFoo = () => <foo bar={bar} baz={baz} />,
-        baz = "baz";
+        renderFoo = () => _ref2,
+        baz = "baz",
+        _ref2 = <foo bar={bar} baz={baz} />;
 
   return renderFoo();
 }
\ No newline at end of file
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-before-hoc/actual.js b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-before-hoc/actual.js
new file mode 100644
index 000000000000..21f7b2ed905d
--- /dev/null
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-before-hoc/actual.js
@@ -0,0 +1,18 @@
+import React from "react";
+
+const HOC = component => component;
+
+const Parent = ({}) => (
+  <div className="parent">
+    <Child/>
+  </div>
+);
+
+export default Parent;
+
+let Child = () => (
+  <div className="child">
+    ChildTextContent
+  </div>
+);
+Child = HOC(Child);
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-before-hoc/expected.js b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-before-hoc/expected.js
new file mode 100644
index 000000000000..8da0cc5ad12f
--- /dev/null
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-before-hoc/expected.js
@@ -0,0 +1,18 @@
+import React from "react";
+
+const HOC = component => component;
+
+const Parent = ({}) => _ref;
+
+export default Parent;
+
+var _ref2 = <div className="child">
+    ChildTextContent
+  </div>;
+
+let Child = () => _ref2;
+Child = HOC(Child);
+
+var _ref = <div className="parent">
+    <Child />
+  </div>;
\ No newline at end of file
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-block-scoped-variables/expected.js b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-block-scoped-variables/expected.js
index 9618e6da028f..ab6ad7d4c478 100644
--- a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-block-scoped-variables/expected.js
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-block-scoped-variables/expected.js
@@ -1,17 +1,11 @@
 function render(flag) {
   if (flag) {
-    var _ret = function () {
-      var bar = "bar";
+    var bar = "bar";
 
-      [].map(() => bar);
+    [].map(() => bar);
 
-      return {
-        v: <foo bar={bar} />
-      };
-    }();
-
-    if (typeof _ret === "object") return _ret.v;
+    return <foo bar={bar} />;
   }
 
   return null;
-}
\ No newline at end of file
+}
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression-constant/actual.js b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression-constant/actual.js
new file mode 100644
index 000000000000..a6c1f9b6ec88
--- /dev/null
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression-constant/actual.js
@@ -0,0 +1,4 @@
+function render() {
+  this.component = "div";
+  return () => <this.component />;
+}
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression-constant/expected.js b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression-constant/expected.js
new file mode 100644
index 000000000000..aa7a9994baeb
--- /dev/null
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression-constant/expected.js
@@ -0,0 +1,7 @@
+function render() {
+  this.component = "div";
+
+  var _ref = <this.component />;
+
+  return () => _ref;
+}
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression-this/actual.js b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression-this/actual.js
new file mode 100644
index 000000000000..bdc61d684a69
--- /dev/null
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression-this/actual.js
@@ -0,0 +1,5 @@
+class Component extends React.Component {
+  subComponent = () => <span>Sub Component</span>
+
+  render = () => <this.subComponent />
+}
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression-this/expected.js b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression-this/expected.js
new file mode 100644
index 000000000000..9ce3a08e7437
--- /dev/null
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression-this/expected.js
@@ -0,0 +1,12 @@
+var _ref = <span>Sub Component</span>;
+
+class Component extends React.Component {
+  constructor(...args) {
+    var _temp;
+
+    var _ref2 = <this.subComponent />;
+
+    return _temp = super(...args), this.subComponent = () => _ref, this.render = () => _ref2, _temp;
+  }
+
+}
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression-this/options.json b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression-this/options.json
new file mode 100644
index 000000000000..d4789bbda3fb
--- /dev/null
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression-this/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": ["syntax-jsx", "transform-react-constant-elements", "transform-class-properties"]
+}
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression/actual.js b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression/actual.js
new file mode 100644
index 000000000000..2ab59df97b89
--- /dev/null
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression/actual.js
@@ -0,0 +1,6 @@
+const els = {
+  subComponent: () => <span>Sub Component</span>
+};
+class Component extends React.Component {
+  render = () => <els.subComponent />
+}
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression/expected.js b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression/expected.js
new file mode 100644
index 000000000000..fe12eb988d5d
--- /dev/null
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression/expected.js
@@ -0,0 +1,16 @@
+var _ref = <span>Sub Component</span>;
+
+const els = {
+  subComponent: () => _ref
+};
+
+var _ref2 = <els.subComponent />;
+
+class Component extends React.Component {
+  constructor(...args) {
+    var _temp;
+
+    return _temp = super(...args), this.render = () => _ref2, _temp;
+  }
+
+}
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression/options.json b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression/options.json
new file mode 100644
index 000000000000..d4789bbda3fb
--- /dev/null
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": ["syntax-jsx", "transform-react-constant-elements", "transform-class-properties"]
+}
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-deopt/actual.js b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-deopt/actual.js
new file mode 100644
index 000000000000..4df51832c7ce
--- /dev/null
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-deopt/actual.js
@@ -0,0 +1,5 @@
+// https://github.com/facebook/react/issues/3226
+// Not safe to reuse because it is mutable
+function render() {
+  return <div style={{ width: 100 }} />;
+}
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-deopt/expected.js b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-deopt/expected.js
new file mode 100644
index 000000000000..4df51832c7ce
--- /dev/null
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-deopt/expected.js
@@ -0,0 +1,5 @@
+// https://github.com/facebook/react/issues/3226
+// Not safe to reuse because it is mutable
+function render() {
+  return <div style={{ width: 100 }} />;
+}
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression-2/actual.js b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression-2/actual.js
new file mode 100644
index 000000000000..0acb75cfaf6a
--- /dev/null
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression-2/actual.js
@@ -0,0 +1,5 @@
+function render(offset) {
+  return function () {
+    return <div tabIndex={offset + 1} />;
+  };
+}
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression-2/expected.js b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression-2/expected.js
new file mode 100644
index 000000000000..65df627806b2
--- /dev/null
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression-2/expected.js
@@ -0,0 +1,8 @@
+function render(offset) {
+  var _ref = <div tabIndex={offset + 1} />;
+
+  return function () {
+    return _ref;
+  };
+}
+
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression-3/actual.js b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression-3/actual.js
new file mode 100644
index 000000000000..c6b89c77fd1a
--- /dev/null
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression-3/actual.js
@@ -0,0 +1,10 @@
+const OFFSET = 3;
+
+var Foo = React.createClass({
+  render: function () {
+    return (
+      <div tabIndex={OFFSET + 1} />
+    );
+  }
+});
+
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression-3/expected.js b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression-3/expected.js
new file mode 100644
index 000000000000..e709176c4870
--- /dev/null
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression-3/expected.js
@@ -0,0 +1,10 @@
+const OFFSET = 3;
+
+var _ref = <div tabIndex={OFFSET + 1} />;
+
+var Foo = React.createClass({
+  render: function () {
+    return _ref;
+  }
+});
+
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression/actual.js b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression/actual.js
new file mode 100644
index 000000000000..5131c839899b
--- /dev/null
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression/actual.js
@@ -0,0 +1,11 @@
+var Foo = React.createClass({
+  render: function () {
+    return (
+      <div data-text={
+        "Some text, " +
+        "and some more too."
+      } />
+    );
+  }
+});
+
diff --git a/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression/expected.js b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression/expected.js
new file mode 100644
index 000000000000..a7afcb1d6edf
--- /dev/null
+++ b/packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression/expected.js
@@ -0,0 +1,8 @@
+var _ref = <div data-text={"Some text, " + "and some more too."} />;
+
+var Foo = React.createClass({
+  render: function () {
+    return _ref;
+  }
+});
+
diff --git a/packages/babel-plugin-transform-react-display-name/package.json b/packages/babel-plugin-transform-react-display-name/package.json
index 09a05f65e01c..4ae2eb1509a1 100644
--- a/packages/babel-plugin-transform-react-display-name/package.json
+++ b/packages/babel-plugin-transform-react-display-name/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-plugin-transform-react-display-name",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Add displayName to React.createClass calls",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-react-display-name",
   "license": "MIT",
diff --git a/packages/babel-plugin-transform-react-jsx/package.json b/packages/babel-plugin-transform-react-jsx/package.json
index 1f6033802360..17391a3be506 100644
--- a/packages/babel-plugin-transform-react-jsx/package.json
+++ b/packages/babel-plugin-transform-react-jsx/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-plugin-transform-react-jsx",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Turn JSX into React function calls",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-react-jsx",
   "license": "MIT",
@@ -9,7 +9,7 @@
     "babel-plugin"
   ],
   "dependencies": {
-    "babel-helper-builder-react-jsx": "^6.22.0",
+    "babel-helper-builder-react-jsx": "^6.23.0",
     "babel-plugin-syntax-jsx": "^6.8.0"
   },
   "devDependencies": {
diff --git a/packages/babel-plugin-transform-runtime/package.json b/packages/babel-plugin-transform-runtime/package.json
index 4caf8e695188..98e5430b0783 100644
--- a/packages/babel-plugin-transform-runtime/package.json
+++ b/packages/babel-plugin-transform-runtime/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-plugin-transform-runtime",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Externalise references to helpers and builtins, automatically polyfilling your code without polluting globals",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-runtime",
   "license": "MIT",
diff --git a/packages/babel-polyfill/package.json b/packages/babel-polyfill/package.json
index 77a62a8485d9..673e8166fe07 100644
--- a/packages/babel-polyfill/package.json
+++ b/packages/babel-polyfill/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-polyfill",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Provides polyfills necessary for a full ES2015+ environment",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://babeljs.io/",
diff --git a/packages/babel-preset-flow/.npmignore b/packages/babel-preset-flow/.npmignore
new file mode 100644
index 000000000000..47cdd2c65551
--- /dev/null
+++ b/packages/babel-preset-flow/.npmignore
@@ -0,0 +1,3 @@
+src
+test
+node_modules
diff --git a/packages/babel-preset-flow/README.md b/packages/babel-preset-flow/README.md
new file mode 100644
index 000000000000..26593bd87824
--- /dev/null
+++ b/packages/babel-preset-flow/README.md
@@ -0,0 +1,53 @@
+# babel-preset-flow
+
+> Babel preset for all Flow plugins.
+
+This preset includes the following plugins:
+
+- [transform-flow-strip-types](https://babeljs.io/docs/plugins/transform-flow-strip-types/)
+
+## Example
+
+**In**
+
+```javascript
+function foo(one: any, two: number, three?): string {}
+```
+
+**Out**
+
+```javascript
+function foo(one, two, three) {}
+```
+
+## Installation
+
+```sh
+npm install --save-dev babel-preset-flow
+```
+
+## Usage
+
+### Via `.babelrc` (Recommended)
+
+**.babelrc**
+
+```json
+{
+  "presets": ["flow"]
+}
+```
+
+### Via CLI
+
+```sh
+babel --presets flow script.js
+```
+
+### Via Node API
+
+```javascript
+require("babel-core").transform("code", {
+  presets: ["flow"]
+});
+```
diff --git a/packages/babel-preset-flow/package.json b/packages/babel-preset-flow/package.json
new file mode 100644
index 000000000000..e9f4cb59797e
--- /dev/null
+++ b/packages/babel-preset-flow/package.json
@@ -0,0 +1,18 @@
+{
+  "name": "babel-preset-flow",
+  "version": "6.23.0",
+  "description": "Babel preset for all Flow plugins.",
+  "author": "James Kyle <me@thejameskyle.com>",
+  "repository": "https://github.com/babel/babel/tree/master/packages/babel-preset-flow",
+  "license": "MIT",
+  "main": "lib/index.js",
+  "keywords": [
+    "babel-preset",
+    "flowtype",
+    "flow",
+    "types"
+  ],
+  "dependencies": {
+    "babel-plugin-transform-flow-strip-types": "^6.22.0"
+  }
+}
diff --git a/packages/babel-preset-flow/src/index.js b/packages/babel-preset-flow/src/index.js
new file mode 100644
index 000000000000..8251ca827050
--- /dev/null
+++ b/packages/babel-preset-flow/src/index.js
@@ -0,0 +1,7 @@
+import transformFlowStripTypes from "babel-plugin-transform-flow-strip-types";
+
+export default {
+  plugins: [
+    transformFlowStripTypes
+  ]
+};
diff --git a/packages/babel-preset-react/README.md b/packages/babel-preset-react/README.md
index aceb108affd3..591a59547b89 100644
--- a/packages/babel-preset-react/README.md
+++ b/packages/babel-preset-react/README.md
@@ -2,11 +2,10 @@
 
 > Babel preset for all React plugins.
 
-This preset includes the following plugins:
+This preset includes the following plugins/presets:
 
-- [syntax-flow](https://babeljs.io/docs/plugins/syntax-flow/)
+- [preset-flow](https://babeljs.io/docs/plugins/preset-flow/)
 - [syntax-jsx](https://babeljs.io/docs/plugins/syntax-jsx/)
-- [transform-flow-strip-types](https://babeljs.io/docs/plugins/transform-flow-strip-types/)
 - [transform-react-jsx](https://babeljs.io/docs/plugins/transform-react-jsx/)
 - [transform-react-display-name](https://babeljs.io/docs/plugins/transform-react-display-name/)
 
diff --git a/packages/babel-preset-react/package.json b/packages/babel-preset-react/package.json
index 378b3a04563d..1a4bf7c55d52 100644
--- a/packages/babel-preset-react/package.json
+++ b/packages/babel-preset-react/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-preset-react",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Babel preset for all React plugins.",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://babeljs.io/",
@@ -8,11 +8,10 @@
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-preset-react",
   "main": "lib/index.js",
   "dependencies": {
-    "babel-plugin-syntax-flow": "^6.3.13",
+    "babel-preset-flow": "^6.23.0",
     "babel-plugin-syntax-jsx": "^6.3.13",
-    "babel-plugin-transform-flow-strip-types": "^6.22.0",
-    "babel-plugin-transform-react-display-name": "^6.22.0",
-    "babel-plugin-transform-react-jsx": "^6.22.0",
+    "babel-plugin-transform-react-display-name": "^6.23.0",
+    "babel-plugin-transform-react-jsx": "^6.23.0",
     "babel-plugin-transform-react-jsx-source": "^6.22.0",
     "babel-plugin-transform-react-jsx-self": "^6.22.0"
   }
diff --git a/packages/babel-preset-react/src/index.js b/packages/babel-preset-react/src/index.js
index 55dd6bbd8d54..361238658ef9 100644
--- a/packages/babel-preset-react/src/index.js
+++ b/packages/babel-preset-react/src/index.js
@@ -1,6 +1,5 @@
+import presetFlow from "babel-preset-flow";
 import transformReactJSX from "babel-plugin-transform-react-jsx";
-import transformFlowStripTypes from "babel-plugin-transform-flow-strip-types";
-import transformSyntaxFlow from "babel-plugin-syntax-flow";
 import transformSyntaxJSX from "babel-plugin-syntax-jsx";
 import transformReactDisplayName from "babel-plugin-transform-react-display-name";
 
@@ -9,10 +8,11 @@ import transformReactDisplayName from "babel-plugin-transform-react-display-name
 // import transformReactJSXSelf from "babel-plugin-transform-react-jsx-self";
 
 export default {
+  presets: [
+    presetFlow
+  ],
   plugins: [
     transformReactJSX,
-    transformFlowStripTypes,
-    transformSyntaxFlow,
     transformSyntaxJSX,
     transformReactDisplayName
   ],
diff --git a/packages/babel-register/package.json b/packages/babel-register/package.json
index 0ace0ca3b829..e6e328efc57d 100644
--- a/packages/babel-register/package.json
+++ b/packages/babel-register/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-register",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "babel require hook",
   "license": "MIT",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-register",
@@ -8,7 +8,7 @@
   "main": "lib/node.js",
   "browser": "lib/browser.js",
   "dependencies": {
-    "babel-core": "^6.22.0",
+    "babel-core": "^6.23.0",
     "core-js": "^2.4.0",
     "home-or-tmp": "^3.0.0",
     "lodash": "^4.2.0",
diff --git a/packages/babel-template/package.json b/packages/babel-template/package.json
index 8c36f1655b22..d75b97caaf86 100644
--- a/packages/babel-template/package.json
+++ b/packages/babel-template/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-template",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Generate an AST from a string template.",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://babeljs.io/",
@@ -9,8 +9,8 @@
   "main": "lib/index.js",
   "dependencies": {
     "babylon": "^6.11.0",
-    "babel-traverse": "^6.22.0",
-    "babel-types": "^6.22.0",
+    "babel-traverse": "^6.23.0",
+    "babel-types": "^6.23.0",
     "lodash": "^4.2.0"
   }
 }
diff --git a/packages/babel-traverse/package.json b/packages/babel-traverse/package.json
index 51dff4bfd716..40de088ff39c 100644
--- a/packages/babel-traverse/package.json
+++ b/packages/babel-traverse/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-traverse",
-  "version": "6.22.1",
+  "version": "6.23.1",
   "description": "The Babel Traverse module maintains the overall tree state, and is responsible for replacing, removing, and adding nodes",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://babeljs.io/",
@@ -9,8 +9,8 @@
   "main": "lib/index.js",
   "dependencies": {
     "babel-code-frame": "^6.22.0",
-    "babel-messages": "^6.22.0",
-    "babel-types": "^6.22.0",
+    "babel-messages": "^6.23.0",
+    "babel-types": "^6.23.0",
     "babylon": "^6.15.0",
     "debug": "^2.2.0",
     "globals": "^9.0.0",
@@ -18,6 +18,6 @@
     "lodash": "^4.2.0"
   },
   "devDependencies": {
-    "babel-generator": "^6.22.0"
+    "babel-generator": "^6.23.0"
   }
 }
diff --git a/packages/babel-traverse/src/path/lib/hoister.js b/packages/babel-traverse/src/path/lib/hoister.js
index 93b9323bd35d..69154bbc2d27 100644
--- a/packages/babel-traverse/src/path/lib/hoister.js
+++ b/packages/babel-traverse/src/path/lib/hoister.js
@@ -2,11 +2,27 @@ import { react } from "babel-types";
 import * as t from "babel-types";
 
 const referenceVisitor = {
+  // This visitor looks for bindings to establish a topmost scope for hoisting.
   ReferencedIdentifier(path, state) {
-    if (path.isJSXIdentifier() && react.isCompatTag(path.node.name)) {
+    // Don't hoist regular JSX identifiers ('div', 'span', etc).
+    // We do have to consider member expressions for hoisting (e.g. `this.component`)
+    if (
+      path.isJSXIdentifier() &&
+      react.isCompatTag(path.node.name) &&
+      !path.parentPath.isJSXMemberExpression()
+    ) {
       return;
     }
 
+    // If the identifier refers to `this`, we need to break on the closest non-arrow scope.
+    if (path.node.name === "this") {
+      let scope = path.scope;
+      do {
+        if (scope.path.isFunction() && !scope.path.isArrowFunctionExpression()) break;
+      } while (scope = scope.parent);
+      if (scope) state.breakOnScopePaths.push(scope.path);
+    }
+
     // direct references that we need to track to hoist this to the highest scope we can
     const binding = path.scope.getBinding(path.node.name);
     if (!binding) return;
@@ -15,25 +31,27 @@ const referenceVisitor = {
     // eg. it's in a closure etc
     if (binding !== state.scope.getBinding(path.node.name)) return;
 
-    if (binding.constant) {
-      state.bindings[path.node.name] = binding;
-    } else {
-      for (const violationPath of (binding.constantViolations: Array)) {
-        state.breakOnScopePaths = state.breakOnScopePaths.concat(violationPath.getAncestry());
-      }
-    }
+    state.bindings[path.node.name] = binding;
   }
 };
 
 export default class PathHoister {
   constructor(path, scope) {
+    // Storage for scopes we can't hoist above.
     this.breakOnScopePaths = [];
+    // Storage for bindings that may affect what path we can hoist to.
     this.bindings          = {};
+    // Storage for eligible scopes.
     this.scopes            = [];
+    // Our original scope and path.
     this.scope             = scope;
     this.path              = path;
+    // By default, we attach as far up as we can; but if we're trying
+    // to avoid referencing a binding, we may have to go after.
+    this.attachAfter       = false;
   }
 
+  // A scope is compatible if all required bindings are reachable.
   isCompatibleScope(scope) {
     for (const key in this.bindings) {
       const binding = this.bindings[key];
@@ -45,6 +63,7 @@ export default class PathHoister {
     return true;
   }
 
+  // Look through all scopes and push compatible ones.
   getCompatibleScopes() {
     let scope = this.path.scope;
     do {
@@ -54,6 +73,7 @@ export default class PathHoister {
         break;
       }
 
+      // deopt: These scopes are set in the visitor on const violations
       if (this.breakOnScopePaths.indexOf(scope.path) >= 0) {
         break;
       }
@@ -61,7 +81,7 @@ export default class PathHoister {
   }
 
   getAttachmentPath() {
-    const path = this._getAttachmentPath();
+    let path = this._getAttachmentPath();
     if (!path) return;
 
     let targetScope = path.scope;
@@ -82,8 +102,18 @@ export default class PathHoister {
         // allow parameter references
         if (binding.kind === "param") continue;
 
-        // if this binding appears after our attachment point then don't hoist it
-        if (this.getAttachmentParentForPath(binding.path).key > path.key) return;
+        // if this binding appears after our attachment point, then we move after it.
+        if (this.getAttachmentParentForPath(binding.path).key > path.key) {
+          this.attachAfter = true;
+          path = binding.path;
+
+          // We also move past any constant violations.
+          for (const violationPath of (binding.constantViolations: Array)) {
+            if (this.getAttachmentParentForPath(violationPath).key > path.key) {
+              path = violationPath;
+            }
+          }
+        }
       }
     }
 
@@ -94,11 +124,12 @@ export default class PathHoister {
     const scopes = this.scopes;
 
     const scope = scopes.pop();
+    // deopt: no compatible scopes
     if (!scope) return;
 
     if (scope.path.isFunction()) {
       if (this.hasOwnParamBindings(scope)) {
-        // should ignore this scope since it's ourselves
+        // deopt: should ignore this scope since it's ourselves
         if (this.scope === scope) return;
 
         // needs to be attached to the body
@@ -117,26 +148,30 @@ export default class PathHoister {
     if (scope) return this.getAttachmentParentForPath(scope.path);
   }
 
+  // Find an attachment for this path.
   getAttachmentParentForPath(path) {
     do {
-      if (!path.parentPath ||
-          (Array.isArray(path.container) && path.isStatement()) ||
-          (
-            path.isVariableDeclarator() &&
-            path.parentPath.node !== null &&
-            path.parentPath.node.declarations.length > 1
-          )
-      )
+      if (
+        // Beginning of the scope
+        !path.parentPath ||
+        // Has siblings and is a statement
+        (Array.isArray(path.container) && path.isStatement()) ||
+        // Is part of multiple var declarations
+        (path.isVariableDeclarator() &&
+          path.parentPath.node !== null &&
+          path.parentPath.node.declarations.length > 1))
         return path;
     } while ((path = path.parentPath));
   }
 
+  // Returns true if a scope has param bindings.
   hasOwnParamBindings(scope) {
     for (const name in this.bindings) {
       if (!scope.hasOwnBinding(name)) continue;
 
       const binding = this.bindings[name];
-      if (binding.kind === "param") return true;
+      // Ensure constant; without it we could place behind a reassignment
+      if (binding.kind === "param" && binding.constant) return true;
     }
     return false;
   }
@@ -161,7 +196,8 @@ export default class PathHoister {
     let uid = attachTo.scope.generateUidIdentifier("ref");
     const declarator = t.variableDeclarator(uid, this.path.node);
 
-    attachTo.insertBefore([
+    const insertFn = this.attachAfter ? "insertAfter" : "insertBefore";
+    attachTo[insertFn]([
       attachTo.isVariableDeclarator() ? declarator : t.variableDeclaration("var", [declarator])
     ]);
 
diff --git a/packages/babel-types/README.md b/packages/babel-types/README.md
index 13b2ec3a5a64..683388362925 100644
--- a/packages/babel-types/README.md
+++ b/packages/babel-types/README.md
@@ -930,6 +930,7 @@ Aliases: `ModuleSpecifier`
 
  - `local`: `Identifier` (required)
  - `imported`: `Identifier` (required)
+ - `importKind`: `null | 'type' | 'typeof'` (default: `null`)
 
 ---
 
diff --git a/packages/babel-types/package.json b/packages/babel-types/package.json
index 57c4bc762a15..5ed4524a29b6 100644
--- a/packages/babel-types/package.json
+++ b/packages/babel-types/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-types",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Babel Types is a Lodash-esque utility library for AST nodes",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://babeljs.io/",