[UPDATED]

To be clear, this affects only users that have an actual StackOverflow exception in their own code.

I've isolated the crash to: any StackOverflow exception being thrown while using .Net 3.5 as the Scripting Runtime on macOS. It does not happen with .Net 4.x.

All you need to do is create a new project, set the runtime to 3.5, and add a script like this in an Editor folder:
using UnityEditor;
public class Crash
{
[MenuItem("CRASH/CRASH")]
static void Menu()
{
Menu();
}
}

I've also attached the stacktrace from Xcode but the crash appears to be inside jitted mono code.

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[PREVIOUS DESCRIPTION]

Adding a custom GUI to a GameObject cause a crash. This seems to be OSX only, Windows produces expected StackOverflow console error.

1. What happened
After creating a custom GUILayout Unity crashes.

2. How we can reproduce it using the example you attached
- Open the attached project in 2018.2.0f2
- Open the Test Scene_Dev (If not open already)
- In the Hierarchy select the Airplane GameObject (it has the custom GUI)
Notice Issue >> Crash.

VIDEO ATTACHED: GUILayoutCrash

Line 28 in script IP_BaseAirplaneInput_Editor seems to cause the issue, if commented out the script works fine.

Crash appears in: 2018.2.0f2, 2018.1.4f