`[RelayCommand]` does not work with default/optional arguments as the command parameter

[bzd3y]

Describe the bug

The following command compiles, but causes a runtime error when called.

public override async Task SomeCommandAsync(bool optional = false, CancellationToken cancellationToken = default)
{

}

The same command without the first optional argument does work, i.e. the optional CancellationToken is handled correctly, as far as I can tell.

If it isn't possible to dispatch the command with that default/optional argument, then the analyzer should probably produce a compiler error notifying the user that RelayCommands cannot have optional arguments.

Regression

No response

Steps to reproduce

1. Paste the code above into a class inside a project that references the CommunityToolkit
2. Run the application

Expected behavior

Either pass in the provided value or the default or generate a compiler error to notify the user that commands cannot have optional arguments.

Screenshots

No response

IDE and version

VS 2022

IDE version

No response

Nuget packages

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

Nuget package version(s)

CommunityToolkit.Mvvm 8.4.0

Additional context

No response

Help us help you

No, just wanted to report this