CS9257: "Both partial property declarations must be required or neither may be required" on a required partial property with [ObservableProperty]

[nalka0]

Describe the bug

On main, the below code generates public partial string Foo ... which yields this error:

CS9257: "Both partial property declarations must be required or neither may be required"

It should generate public required partial string Foo ... instead.

public partial class Test : ObservableObject
{
    [ObservableProperty]
    public required partial string Foo { get; set; }
}

Steps to reproduce

1. Run dotnet pack src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.csproj (on the current main)
2. Create a WPF App (.NET 8)
3. Install the package generated by step 1
4. Add <LangVersion>preview</LangVersion> to the .csproj
5. Create a class as follows:

using CommunityToolkit.Mvvm.ComponentModel;

namespace WpfApp1;

public partial class Test : ObservableObject
{
    [ObservableProperty]
    public required partial string Foo { get; set; }
}

Expected behavior

public partial class Test : ObservableObject
{
    [ObservableProperty]
    public required partial string Foo { get; set; }
}

Generates public required partial string Foo ... instead of public partial string Foo ...

IDE and version

VS 2022

IDE version

17.11.5

Nuget packages

• CommunityToolkit.Common
• CommunityToolkit.Diagnostics
• CommunityToolkit.HighPerformance
• CommunityToolkit.Mvvm (aka MVVM Toolkit)

Nuget package version(s)

main (8.4.0-build.11)

Help us help you

Yes, but only if others can assist

[Sergio0694]

Good point, yeah I still need to add support for required properties, since it wasn't an existing scenario before 🙂

[nalka0]

Good point, yeah I still need to add support for required properties, since it wasn't an existing scenario before 🙂

@Sergio0694 Alright, since I picked "Yes, but only if others can assist" for Help us help you, does it mean I should just leave that issue for you? Or should I try to send a PR on this? (feel free to delete that once you reply to keep the issue clean)

[Sergio0694]

I've already fixed this in a branch and was about to open a PR, no worries! Thank you though! 🙂

"Yes, but only if others can assist"

Yes but only if others can assist basically means "I'm willing to contribute this fix if needed". In this case I was just already doing a follow up with some other fixes here and there, so that was not necessary. It doesn't necessarily indicate you have to contribute the fix yourself. I do appreciate it though! This reminds me I should create some "up for grabs" tag to mark items as welcoming contributions.

[nalka0]

Yes but only if others can assist basically means "I'm willing to contribute this fix if needed". In this case I was just already doing a follow up with some other fixes here and there, so that was not necessary.

Alright I see, I was seeing it more like "I'm willing to try fixing it but am not sure I'll be able to do it completely on my own"