Unable to use C#7.0 features in .cs files

[antur84]

Hi

I'm trying to use any C#7.0 feature, like inline out params and digit_separator, in any *Controller.cs, but it won't compile as soon as I install Precompilation 3.3.0 package.

I don't get any error in the Error List, but you can see them in the output build log, that the precompilation compiler does not recognise the new features. If I force the /langlevel:7 flag it will complain that it has to be between 1-6

My easiest way of reproducing is starting a new project in VS (2017 community), MVC, based on net4.6.2.

• In HomeController, use some c#7 features, compile. It won't compile.
• Update nuget packages (which will give you the latest codedom and compilers), compile again. Success, all is good
• Install Precompilation package, compile It won't compile anymore

Any ideas?

[m0sa]

SE Precompilation 3.* is built agains older roslyn packages that don't support c# 7 yet. Try the SE Precompilation pre-release packages (4.0) from the appveyor nuget feed described in the readme.

We're already running it in production on StackOverflow, I just didn't find time yet to do a release to nuget.org.