Preview Error/evaluation error

[pellet]

In my Mac XamForms app I changed a buttons text from "A" to "B" then saw this in the app:

Feature `pattern matching' cannot be used because it is not part of the C# 7.0 language specification

If you need me to get more information somehow let me know, I couldn't see any logs in the application output and I'm not sure where else to look for logs sorry.

[ylatuya]

Your view is using a feature from C# 7.0 and it seems that the evaluator does not support it. Can you try with a different view that does not uses pattern matching?
What Target Framework are you using?

1. Xamarin.Mac Modern
2. Xamarin.Mac Full
3. Any of the unsupported frameworks

[pellet]

I'm targeting Xamarin.Mac Modern.
The code which was causing an issue was:
!(url is null) which is indeed pattern matching.