[Unity] When language version is set to C# 10 InteliSense still thinks it's C# 9

[BarionLP]

Describe the Issue

This is a little known feature, but Unity does support C# 10 features.
When this is enabled all C# 10 features compile without problems but VS Code still displays them as errors.

The generated .csproj still says C# 9, manually overriding this solves the issue until the file gets regenerated

Steps To Reproduce

• enable C# 10 in a (new) project
• use a C# 10 feature (like with on structs (like Vector3) )
• Unity compiles, VS Code displays an error

Expected Behavior

VS Code displays no error

Environment Information

• OS: Windows 11
• Unity: 6000.1.13
• VS Code: 1.102.3
• Unity Extension: 1.1.2

[claudiaregio]

@jbevain to review

[jbevain]

Thanks for reaching out and identifying that scenario. We'll add support for overriding the langversion from a csc.rsp file.

[BarionLP]

if im not mistaken one can have different C# versions per assembly definition so you need to account for this

[jbevain]

Thanks. Yeah that's similar to how we handle custom defines in .rsp files. We have a fix ready that will ship in a next version of the Visual Studio Editor Unity package. Because we do not control entirely when this ships, it might take some time.

If that's important for you, you can move the Visual Studio Editor package locally to your project and we can provide you the patch to support this scenario.

[jbevain]

Scheduled to be shipped in the Visual Studio Editor package 2.0.24.

[BarionLP]

Does the update have a release date yet?
I've been using this a bit more lately and it's starting to get annoying. So if it's still a few months out, I might want the patch.

[jbevain]

Shouldn't be too long now. Unity is working on rolling out the new package.

[BarionLP]

seems like a long rollout phase

[laicasaane]

Scheduled to be shipped in the Visual Studio Editor package 2.0.24.

@jbevain I'm using 2.0.25 atm, the generated csproj does include the csc.rsp file, but it still has no effect on the language version.

csc.rsp

-langVersion:10

Game.Common.csproj

<PropertyGroup>
    <GenerateAssemblyInfo>false</GenerateAssemblyInfo>
    <EnableDefaultItems>false</EnableDefaultItems>
    <LangVersion>9.0</LangVersion>
    <RootNamespace>Game</RootNamespace>
    <OutputType>Library</OutputType>
    <AssemblyName>Game.Common</AssemblyName>
    <TargetFramework>netstandard2.1</TargetFramework>
    <BaseDirectory>.</BaseDirectory>
  </PropertyGroup>
...
  <ItemGroup>
    <None Include="Assets\Game.Common\Game.Common.asmdef" />
    <None Include="Assets\Game.Common\csc.rsp" />
  </ItemGroup>

VSCode still complains about file-scoped namespace.

---

I also include a props file alongside csproj files to enforce language version on IDE, but it has no effect on VSCode too.

Directory.Build.props

<Project>
    <PropertyGroup>
        <LangVersion>10</LangVersion>
    </PropertyGroup>
</Project>

---

On VSCode side:

• VSCode: 1.104.3
• C#: 2.90.60
• C# Dev Kit: 1.50.51
• Unity: 1.1.3

---

On Unity side:

• Unity 6000.2.6f1
• com.unity.ide.visualstudio: 2.0.25

[BarionLP]

I also include a props file alongside csproj files to enforce language version on IDE, but it has no effect on VSCode too.

Directory.Build.props provides default values, they are overwritten by values set in .csproj
Have you tried regenerating the project files?

On my side everything works now, only difference being I'm still on Unity 6000.2.0f1 (bad ik)

[laicasaane]

Have you tried regenerating the project files?

@BarionLP Multiple times, I even delete the old files then regenerate them. To be really sure, I've just done that again.

Btw, where do you put the csc.rsp file? I put each csc.rsp at the location of a .asmdef.

Directory.Build.props provides default values, they are overwritten by values set in .csproj

In my experience of using props file it's the opposite. Because before version 2.0.24 VS 2022 and VSCode still use language version defined in the props file.