diff --git a/packages/babel-code-frame/test/index.js b/packages/babel-code-frame/test/index.js
new file mode 100644
index 0000000000..02a36f9f8e
--- /dev/null
+++ b/packages/babel-code-frame/test/index.js
@@ -0,0 +1,5 @@
+var buildCodeFrame = require("..");
+
+suite("babel-code-frame", function () {
+
+});
diff --git a/packages/babel-core/src/tools/build-external-helpers.js b/packages/babel-core/src/tools/build-external-helpers.js
index 9bc0221977..fd1e91940b 100644
--- a/packages/babel-core/src/tools/build-external-helpers.js
+++ b/packages/babel-core/src/tools/build-external-helpers.js
@@ -73,8 +73,26 @@ function buildVar(namespace, builder) {
 }
 
 function buildHelpers(body, namespace, whitelist) {
+  function shouldIgnore(name) {
+    if (!whitelist) {
+      return false;
+    }
+
+    // check for the raw name
+    if (whitelist.indexOf(name) >= 0) {
+      return false;
+    }
+
+    // typeof -> _typeof
+    if (name[0] === "_" && whitelist.indexOf(name.slice(1)) >= 0) {
+      return false;
+    }
+
+    return true;
+  }
+
   each(helpers.list, function (name) {
-    if (whitelist && whitelist.indexOf(name) === -1) return;
+    if (shouldIgnore(name)) return;
 
     let key = t.identifier(t.toIdentifier(name));
     body.push(t.expressionStatement(
diff --git a/packages/babel-core/src/transformation/file/options/parsers.js b/packages/babel-core/src/transformation/file/options/parsers.js
index 5b5c57faaa..840c6e5f6c 100644
--- a/packages/babel-core/src/transformation/file/options/parsers.js
+++ b/packages/babel-core/src/transformation/file/options/parsers.js
@@ -3,10 +3,6 @@
 import slash from "slash";
 import * as util from "../../../util";
 
-export function number(val: any): number {
-  return +val;
-}
-
 export let filename = slash;
 
 export function boolean(val: any): boolean {
diff --git a/packages/babel-core/test/api.js b/packages/babel-core/test/api.js
index e279d5f613..93fb13abe3 100644
--- a/packages/babel-core/test/api.js
+++ b/packages/babel-core/test/api.js
@@ -1,7 +1,5 @@
-require("../lib/api/node");
-
+var babel                = require("../lib/api/node");
 var buildExternalHelpers = require("../lib/tools/build-external-helpers");
-var transform            = require("../lib/api/node").transform;
 var Pipeline             = require("../lib/transformation/pipeline");
 var sourceMap            = require("source-map");
 var assert               = require("assert");
@@ -19,12 +17,24 @@ function assertNotIgnored(result) {
 function transformAsync(code, opts) {
   return {
     then: function (resolve) {
-      resolve(transform(code, opts));
+      resolve(babel.transform(code, opts));
     }
   };
 }
 
 suite("api", function () {
+  test("transformFile", function (done) {
+    babel.transformFile(__dirname + "/fixtures/api/file.js", {}, function (err, res) {
+      if (err) return done(err);
+      assert.equal(res.code, "foo();");
+      done();
+    });
+  });
+
+  test("transformFileSync", function () {
+    assert.equal(babel.transformFileSync(__dirname + "/fixtures/api/file.js", {}).code, "foo();");
+  });
+
   test("options merge backwards", function () {
     return transformAsync("", {
       presets: [__dirname + "/../../babel-preset-es2015"],
@@ -35,7 +45,7 @@ suite("api", function () {
   });
 
   test("source map merging", function () {
-    var result = transform([
+    var result = babel.transform([
       'function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }',
       '',
       'let Foo = function Foo() {',
@@ -387,5 +397,10 @@ suite("api", function () {
       assert.ok(script.indexOf("classCallCheck") === -1);
       assert.ok(script.indexOf("inherits") === -1);
     });
+
+    test("underscored", function () {
+      var script = buildExternalHelpers(["typeof"]);
+      assert.ok(script.indexOf("typeof") >= 0);
+    });
   });
 });
diff --git a/packages/babel-core/test/fixtures/api/file.js b/packages/babel-core/test/fixtures/api/file.js
new file mode 100644
index 0000000000..a280f9a5cc
--- /dev/null
+++ b/packages/babel-core/test/fixtures/api/file.js
@@ -0,0 +1 @@
+foo();
diff --git a/packages/babel-plugin-transform-regenerator/package.json b/packages/babel-plugin-transform-regenerator/package.json
index 0f6b496566..53b1399120 100644
--- a/packages/babel-plugin-transform-regenerator/package.json
+++ b/packages/babel-plugin-transform-regenerator/package.json
@@ -1,7 +1,7 @@
 {
   "name": "babel-plugin-transform-regenerator",
   "author": "Ben Newman <bn@cs.stanford.edu>",
-  "description": "",
+  "description": "Explode async and generator functions into a state machine.",
   "version": "6.0.18",
   "homepage": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-regenerator",
   "main": "lib/index.js",
diff --git a/packages/babel-plugin-transform-regenerator/src/visit.js b/packages/babel-plugin-transform-regenerator/src/visit.js
index ad22fe3c76..10706d43f0 100644
--- a/packages/babel-plugin-transform-regenerator/src/visit.js
+++ b/packages/babel-plugin-transform-regenerator/src/visit.js
@@ -37,13 +37,7 @@ exports.visitor = {
         return;
       }
 
-      if (node.expression) {
-        // Transform expression lambdas into normal functions.
-        node.expression = false;
-        node.body = t.blockStatement([
-          t.returnStatement(node.body)
-        ]);
-      }
+      path.ensureBlock();
 
       if (node.async) {
         path.get("body").traverse(awaitVisitor);