C# 7.1 project won't build in NCrunch

I have a project in Visual Studio with the Language Version set to 'C# latest minor version (latest)' in VS 2017.3 (so this is C# 7.1 - I have also tried setting the version explicitly to C# 7.1).

This builds find in Visual Studio, but in NCrunch I get errors relating to C# 7.1 features such as the one below:

Tuple element name 'xxxx' is inferred. Please use language version 7.1 or greater to access an element by its inferred name.

Hi, thanks for sharing this problem.

Is this something you can reproduce with a sample project that you can share with me?

So... this morning I installed an update to VS 15.3.2 and the problem disappeared. The syntax I was using isn't actually a 7.1 feature, the error was a regression (you can see the release notes refer to a C# 7.0 Regression in Tuples).

I've tried pretty hard to reproduce an issue using actual C# 7.1 features, but I haven't had any success. So based on that, I think my original comments can be ignored.