Could reproduce on version 4.3.0a5 (796335dfc9e5).

To reproduce:

- Open attached project
- Select "Click Me" > "Produce a scene" in the menu bar and do one of the following actions:

1. Hit Play and observe the crash
2. Save the scene and then reload the scene, and observe the crash

I have observed the following warning, when loading the project, but it is not showing consistently:

"There are inconsistent line endings in the 'Assets/MakeAScene.cs' script. Some are Mac OS X (UNIX) and some are Windows.
This might lead to incorrect line numbers in stacktraces and compiler errors. Many text editors can fix this using Convert Line Endings menu commands."