Created by: gaearon
Should fix #1186 (closed).
The fix works because Webpack dependency bumps webpack-core which bumps source-list-map which includes https://github.com/webpack/source-list-map/pull/2.
That fix was necessary because Babel started adding variable names to source maps in https://github.com/babel/babel/pull/3658 but Webpack didn't add support for this format.