C# 11 required properties do not compile on dotnet 6

[Varorbc]

[Update(jcouv):] The ask is that required properties not be recommended by the IDE on .NET 6 or lower.

Describe the bug

When I want to use required properties in a project targeting net6.0 with LangVersion set to latest I face some compile errors.

To Reproduce

<Project Sdk="Microsoft.NET.Sdk">

    <PropertyGroup>
        <TargetFramework>net6.0</TargetFramework>
        <ImplicitUsings>enable</ImplicitUsings>
        <Nullable>enable</Nullable>
        <LangVersion>latest</LangVersion>
    </PropertyGroup>

</Project>

namespace Csharp11OnDotnet6;

public class Person
{
    public required string Name { get; init; }
}

2.dotnet build

Exceptions (if any)

error CS0656: Missing compiler required member 'System.Runtime.CompilerServices.RequiredMemberAttribute..ctor'
error CS0656: Missing compiler required member 'System.Runtime.CompilerServices.CompilerFeatureRequi
redAttribute..ctor'

Expected Behavior: build successful

[jcouv]

Those errors are expected. The "required members" feature is part of C# 11 and is only supported on .NET 7 and up.

[Varorbc]

@jcouv

1.use The "required members" feature is part of C# 11 and is only supported on .NET 7 and up instead of Missing compiler required member 'System.Runtime.CompilerServices.RequiredMemberAttribute..ctor' for the error

2.In .net 6 projects, IntelliSense should not recommend "required members"

[CyrusNajmabadi]

1.use The "required members" feature is part of C# 11 and is only supported on .NET 7 and up instead of

That's not the case here though. That's what we support (and so we don't do additional work in non-supported scenarios). If you added that attribute somehow, it would work (though we still dont' support that scenario), we don't block it. So the error you're getting is correct. The issue here is that those attributes are missing.

2.In .net 6 projects, IntelliSense should not recommend "required members"

Could you clarify what you mean? We def show things in the completion list to help speed up typing, regardless of version. We don't keep things out of the completion list as that can both be confusing, and it means if you try to type this, you can end up with some other piece of completed text.

[Varorbc]

So the error you're getting is correct. The issue here is that those attributes are missing.

Although I am aware of missing RequiredMemberAttribute, I am not aware that the root cause is that the "required members" feature is part of C# 11 and is only supported on .NET 7 and up, and if this can be explained, it would be better rather than asking questions

Could you clarify what you mean?

[Varorbc]

@CyrusNajmabadi @jcouv Please re-open