Unity C# 8 support

Default interfaces are working in 2021.b.6

Code (CSharp):

1. using UnityEngine;
2.  
3. public class NewBehaviourScript : MonoBehaviour
4. {
5.     private void Start()
6.     {
7.       var someInterface = (ISomeInterface) new SomeInterfaceInheritor();
8.       someInterface.DefaultMethod();
9.     }
10. }
11.  
12. public interface ISomeInterface
13. {
14.     public sealed void DefaultMethod()
15.     {
16.         Debug.Log("Calling public not overridable default method");
17.         OnDefaultMethod();
18.     }
19.  
20.     protected void OnDefaultMethod();
21. }
22.  
23. public class SomeInterfaceInheritor : ISomeInterface
24. {
25.     // public void DefaultMethod() // This is not used because default method is sealed if it is not sealed this will be called instead
26.     // {
27.     //     Debug.Log("Try to override default method");
28.     // }
29.  
30.     void ISomeInterface.OnDefaultMethod()
31.     {
32.        Debug.Log("Calling protected inherited method");
33.     }
34. }

 

How did you manage to do this?
I downloaded 2021.2.0b10 and in Visual Studio still got the same errors about Interfaces and methods.
What steps did you take to make it work and what version of Visual Studio you are using?

 

In Both.

Visual Studio is showing the error that Interface can't implement methods.
And Unity showing error that methods are not implemented even when they are.

Code (CSharp):

1. public interface IMyInterface {
2.  
3.     public sealed void DefaultMethod() {
4.         Debug.Log("Calling public not overridable default method");
5.         OnDefaultMethod();
6.     }
7.  
8.     protected void OnDefaultMethod();
9.  
10. }

Code (CSharp):

1. public class MyClass : MonoBehaviour, IMyInterface {
2.     public void DefaultMethod() {
3.         Debug.Log("");
4.     }
5.  
6.     public void OnDefaultMethod() {
7.         Debug.Log("");
8.     }
9. }

Assets\MyClass.cs(5,39): error CS8704: 'MyClass' does not implement interface member 'IMyInterface.OnDefaultMethod()'. 'MyClass.OnDefaultMethod()' cannot implicitly implement a non-public member.

 

Protected Interface Members Must be Implemented Explicitly:

Code (CSharp):

1. public class MyClass : MonoBehaviour, IMyInterface {
2.     public void DefaultMethod() {
3.         Debug.Log("");
4.     }
5.     public void IMyInterface.OnDefaultMethod() {
6.         Debug.Log("");
7.     }
8. }

 

Thanks! Problem solved, Visual Studio 2019 did the trick.
Finally, defined methods inside Interfaces !

 

I was using Rider

 

So, some people are suggesting that at least some C# 8/9 features are supported, but it appears that Tuple Switches are not, unless I'm doing something wrong.

I have a little function that looks like this:

Code (CSharp):

1. private (int index, Side nodeDirection) NearbyNode (in Vector2 position)
2. {
3.     (int index, Side nodeDirection) = ClosestNode (position);
4.     switch (index, nodeDirection)
5.     {
6.     case (< 2, Side.Right):
7.     case (< 2, Side.Left):
8.     case (2, Side.Right):
9.         return (index + 2, Side.Left);
10.     case (2, Side.Left):
11.     case (> 2, Side.Right):
12.     case (> 2, Side.Left):
13.         return (index - 2, Side.Left);
14.     case ( _, _):
15.         throw new InvalidEnumArgumentException ("Side must be left or right. Unexpected value of " + nodeDirection);
16.     }
17. }

Visual Studio thinks it all looks good, but I'm getting an error in Unity 2020.3.16f1

Assets\Scripts\Actors\AIBehaviorTree\BossBehaviorComponent.cs(125,13): error CS1002: ; expected

Is this not a supported feature? It's sometimes hard to figure out which language features are available and which aren't.

 

This code is using C# 9 feature (comparison operator in pattern matching). C# 9 is supported in Unity 2021.2 and higher

 

How about this? It still warning on 2021.2.18f1

 

It about the nullable support and this warning:
warning CS8669: The annotation for nullable reference types should only be used in code within a ‘#nullable’ annotations context

I can add '#nullable enable' and '#nullable disable' in the source code to disable this warning. I think it may support open nullable support in asmdef file.

 

What I want is to build a package and it could put into any unity project. So the csc.rsp or player settings not work? Is the 'csc.rsp' work in a package or just for a single assembly?
BTW, you mean the 'asmdef' will be deprecated? How about the Assembly and AssemblyBuilder, What the substitution?

 

This new to me. What was happen to asmdef and what would be alternative or are there any problem lead to this decision?

 

They are changing to SDK style csproj. There are more info in the 'Unity Future .NET Development Status' topic and here

, sorry to not be able to pinpoint the exacly response link and timestamps.

[]'s

 

A csc.rsp file is there to tell the compiler specific instructions related to what it should and shouldn't care about. As far as I know, a single csc.rsp file will cover ANY code compiled in your project. (3rd party and Unity packages come in source code form from UPM, so the compiler will apply the rules you set to that code too).

 

c# 10.0?

 

Thank you very much. This video this private so I cannot see it however I think I understand a glimpse of what you describe

 

It was not private yesterday. I wonder what happened.

Edit: the title was "The future of .NET and Unity | Unity at GDC 2022"

 

Was it the video with the bad audio? maybe it was re-uploaded

 

Ah, now that you mention, it was!
Audio was out of sync on left/right channel, so it had a weird echo.

That's probably the reason.

 

About interface default implementation, I encountered crash if I call 'new Test()' with below code.
Seems like it only happens when number of generic argument of ITestBase is less than ITest.

It is silent crash, editor log says "VAR 1 (T2) cannot be expanded in this context with 1 instantiations"

Code (CSharp):

1.  
2. public interface ITestBase<T>
3. {
4.     internal void Process(T x);
5. }
6.  
7. public interface ITest<T1, T2> : ITestBase<T1>
8. {
9.     void ITestBase<T1>.Process(T1 x) { }
10. }
11.  
12. public class Test : ITest<int, int> { }
13.  

It happens in 2021.2.19f1.

 

I just tested it myself and I can confirm it happens in 2022.1.0b12 as well. (You might want to test it on the latest beta version too, but I betcha it will break there as well).

Have you made a bug report for this issue? (If you have not, you can be that here)

I have had similar problems with using Default Interface Implementation within generic interfaces in Unity, but I have not been able to reproduce my issue across multiple machines yet...

Here's me hoping your problem fixes my problem.

 

Sorry to bring this up on this old post but since C# 8 is fully support since 2021.2

Is it include IAsyncEnumerable and await foreach/async stream ? And are there limitation to use it in any platform?

 

Sorry for necro post i am on 2021.3.21f its an non beta i think, should it work on this version too or only beta ones

 

ye it works, my bad

 

@JoshPeterson hope you dont mind me asking in this thread;

Are there plans to support the UnsafeAccessor attribute thats part of .net 8? I just tried in 2023.2 and it couldnt be found, i think it would be tremendously useful for some of the hacks we have to do.

 

It's possible to implement UnsafeAccessor manually without runtime support if you write an IL post processor for it, you just need to make sure to add a

SecurityPermissionAttribute

to the assembly with

SkipVerification

set to true, which gives you roughly the same effect as

IgnoresAccessChecksToAttribute

does in CoreCLR, but in Mono instead (and therefore Unity).

 

Thanks for your prompt reply!