TypeScript: 'typings' duplicate identifier in webpack

I was developing in an Angular 2 project that uses webpack, and I was getting an odd error after webpack had finished making its bundle and began the [default] Checking started in a separate process... phase. I was getting hundreds of lines that looked like this:

[default] /home/user/project/globals/selenium-webdriver/
index.d.ts:5389:5   
    Duplicate identifier 'export='. 

It turns out I had added some extra typing definitions that were getting added to the typings directory in the base path of the project, and those were getting picked up by the type checking process. All I had to do to stop getting the warnings was to add the typings folder to the excluded section of the tsconfig.json file and the errors went away.

 "exclude": [                                 
    "node_modules",                                        
    "typings"                                         
  ],