Version Used:
Microsoft Visual Studio Professional 2017, Version 15.6.6

Steps to Reproduce:
Create new solution and copy-paste sample code there:

using System;
unsafe class Test
{
	public void Method()
	{
		Test obj1 = stackalloc int[2];
	}

	public static implicit operator Test2(int* value)
	{
		return default(Test);
	}
}

Expected Behavior:
No crasg

Actual Behavior:
Visual studio crashes