Hours lost.

Visual Studio test adapter was failing out during the discover phase of the tests with a stack overflow exception, but that's all the information it gave me. The tests simply would not run.

Hunting through the code line by line, I eventually find this.

WHY IS THIS ALLOWED TO COMPILE

I assume it is because that is a statement, and should compile just fine, but fail at runtime.

@ewpratten right. The => is an expression-bodied member, and it gets converted by the compiler to a regular property with a defined getter. So it's basically a method calling itself, which is allowed, but it's a property calling itself, which makes me ask why I would ever want to do that. It seems to me like it's something the compiler could detect.

Maybe file an issue to the compiler devs and ask them to at least emit a warning when the compiler detects code like this https://github.com/dotnet/roslyn

Why? Well, it's just a recursive call. Perfectly legal but it will of course break if there's no way to stop the recursion.