Facebook has a tool that learns to fix bugs automatically?

Direct link to official blog post: https://code.fb.com/developer-tools/getafix-how-facebook-too...

If you have alot of copy pasted code this might work great if you fixed a bug in one place but not the 219 other ones.

TL;DR, this is a tool that automatically adds "if (xx == null) return false" before code potentially throwing NullPointerExceptions.

Who fixes Getafix then?