diff --git a/packages/babel-plugin-transform-es2015-classes/test/fixtures/regression/2775-1/actual.js b/packages/babel-plugin-transform-es2015-classes/test/fixtures/regression/2775-1/actual.js
deleted file mode 100644
index 5236cd8118..0000000000
--- a/packages/babel-plugin-transform-es2015-classes/test/fixtures/regression/2775-1/actual.js
+++ /dev/null
@@ -1,28 +0,0 @@
-var _ = require('underscore'),
-    React = require('react');
-
-class Hello extends React.Component
-{
-    state = {
-        hello: 1
-    };
-
-/*
-    constructor() {
-        super();
-    }
-*/
-
-    render() {
-        var props = _.omit(this.props, 'children');
-        return (
-            <p className="1" {... props}>Hello</p>
-        );
-    }
-
-    foo(param = 1) {
-        this.param = param;
-    }
-}
-
-module.exports = Hello;
diff --git a/packages/babel-plugin-transform-es2015-classes/test/fixtures/regression/2775-1/expected.js b/packages/babel-plugin-transform-es2015-classes/test/fixtures/regression/2775-1/expected.js
deleted file mode 100644
index 584e76fcf5..0000000000
--- a/packages/babel-plugin-transform-es2015-classes/test/fixtures/regression/2775-1/expected.js
+++ /dev/null
@@ -1,46 +0,0 @@
-'use strict';
-
-var _ = require('underscore'),
-    React = require('react');
-
-var Hello = (function (_React$Component) {
-    babelHelpers.inherits(Hello, _React$Component);
-
-    function Hello() {
-        var _temp, _this;
-
-        babelHelpers.classCallCheck(this, Hello);
-        return babelHelpers.possibleConstructorReturn(_this, (_temp = (_this = babelHelpers.possibleConstructorReturn(this, Object.getPrototypeOf(Hello).apply(this, arguments)), _this), _this.state = {
-            hello: 1
-        }, _temp));
-    }
-
-    babelHelpers.createClass(Hello, [{
-        key: 'render',
-
-        /*
-            constructor() {
-                super();
-            }
-        */
-
-        value: function render() {
-            var props = _.omit(this.props, 'children');
-            return React.createElement(
-                'p',
-                babelHelpers.extends({ className: '1' }, props),
-                'Hello'
-            );
-        }
-    }, {
-        key: 'foo',
-        value: function foo() {
-            var param = arguments.length <= 0 || arguments[0] === undefined ? 1 : arguments[0];
-
-            this.param = param;
-        }
-    }]);
-    return Hello;
-})(React.Component);
-
-module.exports = Hello;
diff --git a/packages/babel-plugin-transform-es2015-classes/test/fixtures/spec/accessing-super-class/expected.js b/packages/babel-plugin-transform-es2015-classes/test/fixtures/spec/accessing-super-class/expected.js
index f03982fc1e..413d246ab5 100644
--- a/packages/babel-plugin-transform-es2015-classes/test/fixtures/spec/accessing-super-class/expected.js
+++ b/packages/babel-plugin-transform-es2015-classes/test/fixtures/spec/accessing-super-class/expected.js
@@ -1,10 +1,8 @@
-var _Object$getPrototypeO;
-
 var Test = (function (_Foo) {
   babelHelpers.inherits(Test, _Foo);
 
   function Test() {
-    var _babelHelpers$get;
+    var _Object$getPrototypeO, _babelHelpers$get;
 
     babelHelpers.classCallCheck(this, Test);
 
diff --git a/packages/babel-plugin-transform-es2015-modules-commonjs/src/index.js b/packages/babel-plugin-transform-es2015-modules-commonjs/src/index.js
index ffc45ed476..ed744a5815 100644
--- a/packages/babel-plugin-transform-es2015-modules-commonjs/src/index.js
+++ b/packages/babel-plugin-transform-es2015-modules-commonjs/src/index.js
@@ -82,6 +82,7 @@ export default function () {
       for (let reid of exports) {
         node = buildExportsAssignment(reid, node).expression;
       }
+
       path.replaceWith(node);
     },
 
diff --git a/packages/babel-traverse/package.json b/packages/babel-traverse/package.json
index d352a29b9e..a7639790c4 100644
--- a/packages/babel-traverse/package.json
+++ b/packages/babel-traverse/package.json
@@ -13,6 +13,7 @@
     "babel-runtime": "^5.0.0",
     "babel-types": "^6.1.18",
     "babylon": "^6.1.18",
+    "debug": "^2.2.0",
     "globals": "^8.3.0",
     "invariant": "^2.1.0",
     "lodash": "^3.10.1",
diff --git a/packages/babel-traverse/src/context.js b/packages/babel-traverse/src/context.js
index ea9f1e56dc..e530316e85 100644
--- a/packages/babel-traverse/src/context.js
+++ b/packages/babel-traverse/src/context.js
@@ -53,13 +53,17 @@ export default class TraversalContext {
     });
   }
 
-  maybeQueue(path) {
+  maybeQueue(path, notPriority?: boolean) {
     if (this.trap) {
       throw new Error("Infinite cycle detected");
     }
-    
+
     if (this.queue) {
-      this.priorityQueue.push(path);
+      if (notPriority) {
+        this.queue.push(path);
+      } else {
+        this.priorityQueue.push(path);
+      }
     }
   }
 
diff --git a/packages/babel-traverse/src/path/context.js b/packages/babel-traverse/src/path/context.js
index 1746863997..aa84e7e6fe 100644
--- a/packages/babel-traverse/src/path/context.js
+++ b/packages/babel-traverse/src/path/context.js
@@ -7,6 +7,8 @@ import traverse from "../index";
 export function call(key): boolean {
   let opts = this.opts;
 
+  this.debug(() => key);
+
   if (this.node) {
     if (this._call(opts[key])) return true;
   }
@@ -28,7 +30,7 @@ export function _call(fns?: Array<Function>): boolean {
     if (!node) return true;
 
     let ret = fn.call(this.state, this, this.state);
-    if (ret) throw new Error("Unexpected return value from visitor method " + fn);
+    if (ret) throw new Error(`Unexpected return value from visitor method ${fn}`);
 
     // node has been replaced, it will have been requeued
     if (this.node !== node) return true;
@@ -58,9 +60,11 @@ export function visit(): boolean {
   }
 
   if (this.call("enter") || this.shouldSkip) {
+    this.debug(() => "Skip...");
     return this.shouldStop;
   }
 
+  this.debug(() => "Recursing into...");
   traverse.node(this.node, this.opts, this.scope, this.state, this, this.skipKeys);
 
   this.call("exit");
diff --git a/packages/babel-traverse/src/path/index.js b/packages/babel-traverse/src/path/index.js
index 4732638ec6..9ddbc106c4 100644
--- a/packages/babel-traverse/src/path/index.js
+++ b/packages/babel-traverse/src/path/index.js
@@ -3,6 +3,7 @@
 import type Hub from "../hub";
 import type TraversalContext from "../context";
 import * as virtualTypes from "./lib/virtual-types";
+import buildDebug from "debug";
 import { PATH_CACHE_KEY } from "./constants";
 import invariant from "invariant";
 import traverse from "../index";
@@ -10,6 +11,8 @@ import assign from "lodash/object/assign";
 import Scope from "../scope";
 import * as t from "babel-types";
 
+let debug = buildDebug("babel");
+
 export default class NodePath {
   constructor(hub: Hub, parent: Object) {
     this.parent = parent;
@@ -141,7 +144,7 @@ export default class NodePath {
     this.node[key] = node;
   }
 
-  dump() {
+  getPathLocation(): string {
     let parts = [];
     let path = this;
     do {
@@ -149,7 +152,12 @@ export default class NodePath {
       if (path.inList) key = `${path.listKey}[${key}]`;
       parts.unshift(key);
     } while(path = path.parentPath);
-    console.log(parts.join("."));
+    return parts.join(".");
+  }
+
+  debug(buildMessage: Function) {
+    if (!debug.enabled) return;
+    debug(`${this.getPathLocation()} ${this.type}: ${buildMessage()}`);
   }
 }
 
diff --git a/packages/babel-traverse/src/path/modification.js b/packages/babel-traverse/src/path/modification.js
index d386976990..09bb17533d 100644
--- a/packages/babel-traverse/src/path/modification.js
+++ b/packages/babel-traverse/src/path/modification.js
@@ -69,9 +69,10 @@ export function _containerInsert(from, nodes) {
 
   for (let path of paths) {
     path.setScope();
+    path.debug(() => "Inserted.");
 
     for (let context of contexts) {
-      context.maybeQueue(path);
+      context.maybeQueue(path, true);
     }
   }
 
diff --git a/packages/babel-traverse/src/path/replacement.js b/packages/babel-traverse/src/path/replacement.js
index fca7bd27f2..8c659c0860 100644
--- a/packages/babel-traverse/src/path/replacement.js
+++ b/packages/babel-traverse/src/path/replacement.js
@@ -164,6 +164,8 @@ export function _replaceWith(node) {
     t.validate(this.parent, this.key, node);
   }
 
+  this.debug(() => `Replace with ${node && node.type}`);
+  
   this.node = this.container[this.key] = node;
 }