Question How to enable c# 8?

I just updated to 2020.2.0a12 via Hub, patch notes say compiling scripts with c# 8 is now available but my project is still on c# 7.3

 

Same. I was waiting for this feature, but the default projects get set to C# 7.3 still :-(

 

In the Visual Studio Editor package, ProjectGeneration.cs file you find the following:

Code (CSharp):

1.             var targetLanguageVersion = "latest"; // danger: latest is not the same absolute value depending on the VS version.
2.  
3.             if (m_CurrentInstallation != null && m_CurrentInstallation.SupportsCSharp8)
4.             {
5.                 // Current installation is compatible with C# 8.
6.                 // But Unity has no support for C# 8 constructs so far, so tell the compiler to accept only C# 7.3 or lower.
7.                 targetLanguageVersion = "7.3";
8.             }

My guess is they need to update this package and remove that if statement. I tried a few C# 8 language features and they seem to work. You can manually edit the autogenerated .csproj and change the LangVersion value to 'latest' to not get errors in Visual Studio, but it will be overwritten at some point.

EDIT:
A solution for now is to install the previous version 2.0.0 of the Visual Studio Editor package.
That if statement was added only on the latest 2.0.1 version.
https://docs.unity3d.com/Packages/com.unity.ide.visualstudio@2.0/changelog/CHANGELOG.html

 

Another option if you want to stick with the 2.01 version is to cut/paste the package from /Library/PackageCache/ to /Packages/ and comment out those lines manually.

 

And if you're brave, create a csc.rsp text file in the root of your project and add the line

-nullable:enable

 

It looks like

<Nullable>enable</Nullable>

is ignored by Visual Studio on old style .csproj files. The only way to get the warnings is to add

#nullable enable

to each .cs file.
Would be nice if the VS editor package updated to the new csproj style.

 

Ah, of course it appears that they didn't do basic testing.

It would also be nice if the generated solution was placed somewhere in the Library folder so it doesn't clutter the project root. Also, NuGet support in the Package Manager, but that's another story.

 

In alpha releases I guess we're the basic testing.

 

Not library, but definitely not root. I use docfx to generate my documentation which needs to know where the csprojs are generated, so as long as they're in one consistent self contained location I'm happy. Definitely don't like how cluttered root gets once you start using asmdefs and external plugins a lot

 

This!

Made by a Unity employee @xoofx

https://github.com/xoofx/UnityNuGet

 

Hold up. The .NET Core prototype, now this? Both were made by him, and neither got picked up officially.

EDIT: Oh, spoke too soon. It's a limited selection, not a proper integration.

 

Why not Library? Definitely not the root of Library either — something like `Library\GeneratedSolution`.

 

The reason is because not all packages target .NET Standard 2.0 or work across all platforms.

But changing that json you could easily support any package supporting .NET Standard 2.0 really easy.

Unfortunately, it's like this...

In fact, it's even worse, Unity reinventing the wheel and making a mess of it:

https://docs.unity3d.com/Packages/com.unity.nuget.newtonsoft-json@2.0/manual/index.html

 

Can't you just check the dependency list? They have

.NETStandard,Version=v2.0

there. And it should be the user's responsibility to check whether a package supports all platforms that they're targeting.
NuGet mirror packages... yeah. Goddammit.

EDIT: Uh, yeah, I see I didn't quite read the FAQ.

 

That could work, disregard my straight "no" for library, it just needs to be self contained and reasonable to find. Since package cache gets its own top level folder it feels like a top level solution folder would be fine

 

I tried editing the visual studio package to change the location of the solution and project files. It seems to require simple changes to only 3 methods. I only tested it briefly but seems to be working.

Code (CSharp):

1.         public string ProjectFile(Assembly assembly)
2.         {
3.             return Path.Combine(ProjectDirectory, "Library", "VSSolution", $"{m_AssemblyNameProvider.GetAssemblyName(assembly.outputPath, assembly.name)}.csproj");
4.          // Change Library and VSSolution to any other path.
5.         }
6.  
7.         public string SolutionFile()
8.         {
9.             return Path.Combine(FileUtility.Normalize(ProjectDirectory), "Library", "VSSolution", $"{InvalidCharactersRegexPattern.Replace(m_ProjectName, "_")}.sln");
10.         // Same as above.
11.         }
12.  
13.         string EscapedRelativePathFor(string file)
14.         {
15.             var projectDir = FileUtility.Normalize(ProjectDirectory);
16.             file = FileUtility.Normalize(file);
17.             var path = SkipPathPrefix(file, projectDir);
18.  
19.             if (!Path.IsPathRooted(path)) // you need to add this
20.                 path = Path.Combine("..\\..\\", path); // you need to add this
21. ...
22.  

There's also a WriteAllText method where you could make it check/add the new folder in case it doesn't exist.

 

I filed a bug for this in the Tools for Unity and we'll investigate the fix. For future, let us know via the Help > Report a Problem menu in Visual Studio too.

 

How do I get C#8 happening with Rider?

 

Just seems to work for me.

 

Without needing to do anything?
Tried inserting this in my code but it won't let me...

Code (CSharp):

1. foreach(var item in 1..5)
2.             {
3.                 Debug.Log(item);
4.             }

Doesn't recognise 1..5 as a range.

 

You need the System.Index and System.Range types, which aren't part of .NET Standard 2.0. There is currently no official package available to add them either. You can either copy their code into your project, or use an unofficial NuGet package that provides them such as Sdcb.System.Range or IndexRange.

 

Cheers @TheZombieKiller Sounds more painful to set up than I imagined.

 

Response from JetBrains..."If you open your Unity project in Rider, then in Explorer change Unity view to Solution one, right-click on project and click Properties you can select preferred version of the C# and enable Nullable reference types."

 

This wouldn't work even if it did recognize it as a Range. Ranges by themselves are not iterable, especially ranges like (1..^5) or (..)

 

Whoops. Cheers

 

You're not far off, there's a proposal to support GetEnumerator as an extension method.
https://github.com/dotnet/csharplang/issues/3194
The last comment uses range as an example.

 

hey guys, sorry for jumping in late—any idea on how I might get C#8 to work with VSCode and the 2020 alpha? all help is much appreciated!

 

Since unity regenerates the csproj files everytime, this works until the next recompilation. My guess is, that there needs to be an option inside unity .asmdef files.

 

You can modify the csproj and sln files after they get generated within Unity automatically as well via editor scripts

 

For Rider 2020.2, (I am one of the devs) there should be no need to modify csproj.
We auto-detect C# lang level by either presence of CSharp80Support folder or analyzing Roslyn in Unity installation.
If this is not happening for you for some unknown reason - please report a bug from Rider with Help->Report a bug.

 

To avoid Unity resetting my solution properties every time, I added a

Directory.Build.props

file with the following content to the root of my project

Code (XML):

1.  
2.  
3. <Project>
4.  
5.   <PropertyGroup>
6.     <Nullable>enable</Nullable>
7.     <LangVersion>8.0</LangVersion>
8.   </PropertyGroup>
9. </Project>
10.  

Hope this helps you!

 

see also https://youtrack.jetbrains.com/issue/RIDER-50960

 

how do i get this to work?

 

I don't think the current version of Unity's Mono supports indices. System.Index is not available in .NET Framework 4.x nor .NET Standard 2.0

 

ERROR: please use language version 10.0 or greater