Feature `xxx' cannot be used because it is not part of the C# 4.0 language specification

I'm importing the window GUI to my project but i'm getting error

Assets/IgniteModule/GUI/Elements/IgniteFoldout.cs(25,47): error CS1644: Feature `expression bodied members' cannot be used because it is not part of the C# 4.0 language specification



I already changed language to 6 in Visual Studio but still same problem

How can i fix it?

 

same problem here:

I think I accidentally downgraded Visual Studio when prompted by an asset from the asset store.
It gave some warning about using a different version of c#, and that I could always revert back, so I said "OK"

But now lots of things are going kind of haywire.

Pretty sure I need to make Visual Studio compile in c# 6 again, just not sure how.

 

EDIT May 2, 2019:
Lots of people liked this post.
Visual Studio 2019 is out now.
Follow along with this video (except instead of 2017, use VS 2019)

That made me golden. (Unity 2019.1)



OLDER POST:
Here is what worked for me:

go to about 4:00.

(in case the video is gone, for you frustrated future travelers, landing on this thread: currently (2018.3), you go to edit - project settings - player - other settings. Scroll down to configuration, and change scripting runtime version to .net 4.x (or newest), and API compatibility level to .Net 4.x. Unity will restart, and then scripts using newer nomenclature should work. (ie c# 6.0)

Also, when you open your script again in visual studio, you will be prompted multiple times that 4.x is not installed. Just choose the first option and hit ok or apply or whatever as many times as you have to.

 

Make sure the Unity project is also set to .NET 4.5.

 

Don't listen to me. Now it seems VS 2017 and Unity are not quite communicating. VS 2017 intellisense does not recognize simple classes like monobehaviour (was teal, now is white like everything else). It also does not seem to be highlighting errors like it used to.

I cant remember where it all went wrong, I think it had something to do with installing an app that was using the old prefab system (2018.3 introduced a new prefab system).

Just another unexpected muddy road in a difficult campaign.

 

Sorry, but was listening to you and got everything right. Thanks a lot mate!

 

Thank you for posting this! It solved my problem perfectly.

(in case the video is gone, for you frustrated future travelers, landing on this thread: currently (2018.3), you go to edit - project settings - player - other settings. Scroll down to configuration, and change scripting runtime version to .net 4.x (or newest), and API compatibility level to .Net 4.x. Unity will restart, and then scripts using newer nomenclature should work. (ie c# 6.0)

Also, when you open your script again in visual studio, you will be prompted multiple times that 4.x is not installed. Just choose the first option and hit ok or apply or whatever as many times as you have to.​

 

tnx for this, solved my issues also

 

Thanks for the replies! I was getting some 60-odd errors for this "cannot be used because it is part of the C# 4.0 language specification" reason, after I backed up my project (zipped up the folder) and reimported it on my Surface Pro where I had just reinstalled Windows.

I went into the Project Settings -> Player -> Other and then changed "Scripting Runtime Version" from "3.5" (which it said was deprecated) to ".NET 4.x Equivalent" and changed "Api Compatibility Level" from ".NET Standard 2.0" to ".NET 4.x" and restarted Unity.

After that project compiled without error and I was able to build/play it. Thanks again!

 

thanks bruh

 

Thanks G