1. Create a UWP app in Visual Studio 2017 (comes with a 100K line generated winrtrefs.d.ts file)
2. Type something that references the Windows APIs (I've been typing Windows.Perception.People.HeadPose, but any other type will work) and hit F12

EXPECTED:
Operation completes reasonably quickly (under 10 seconds?)

ACTUAL:
Took over 7 minutes on my machine

This is the offending loop.

The file is massive, but in TypeScript 2.8 the same operation only took a second or two. Go to definition should scale gracefully.