Steps to reproduce
1) Extract and open the project attached by user (src.zip) in Unity
2) Go to /Assets/scenes and open scene 'main.unity'
3) Press 'Play'
4) Unity crashes

Note: deleting the 'Project Settings' and 'Library' folders results in Unity crashing upon opening scene without even playing it (5.4.0b15).
Note#2: when filtering out assets to only display all of the scripts in the project and then trying to open any script by double-clicking it, Unity also crashes. This only occurs in 5.4.0b15.

Bug reproduced on:
5.4.0b15, 5.3.4f1, 5.3.1f1

Not reproduced on:
5.2.2f1