(cloudwatch) System.ArgumentException : Could not infer JSII type for .NET type 'IWidget' (Parameter 'type')

[ghost]

When trying to create a Dashboard using Dashboard props and IWidget Jagged array in the props, the unit test fail with error:
System.ArgumentException : Could not infer JSII type for .NET type 'IWidget' (Parameter 'type')

(dotnet build will compile the code successfully, while the App.Synth will fail)

Create the dashboard empty & adding the widget using the AddWidgets method works as expected.

Reproduction Steps

    public IResource CreateCloudWatchDashboard()
    {
    IWidget[][] widgets = new IWidget[1][]; 
    
    widgets[0]= new IWidget[1];

    widgets[0][0] = new LogQueryWidget (new LogQueryWidgetProps() {
        Height=6,
        Width=24,
        LogGroupNames=new []{"/some/valid/groupname"},
        Title="Task Activity Logs",
        QueryLines=new []{"some valid Query lines"},
        View=LogQueryVisualizationType.TABLE,
        Region="a valid region code"
    });

    var myDashboard = new Dashboard(Scope,  "dashboard", new DashboardProps()
    {
        DashboardName="Some Name",
        Widgets= widgets 
    
    } );
    return null;
   }

What did you expect to happen?

App.Synth() generates a valid CloudFormation template.

What actually happened?

System.ArgumentException : Could not infer JSII type for .NET type 'IWidget' (Parameter 'type')

Environment

• CDK CLI Version : 1.85.0
• Framework Version: .NET Core 3.1.11
• Node.js Version: 14.15.2
• OS : Windows 10 64bits
• Language (Version): C#

Other

The following code will work as expected:

    public IResource CreateCloudWatchDashboard()
    {
    IWidget[][] widgets = new IWidget[1][]; 
    
    widgets[0]= new IWidget[1];

    widgets[0][0] = new LogQueryWidget (new LogQueryWidgetProps() {
        Height=6,
        Width=24,
        LogGroupNames=new []{"/some/valid/groupname"},
        Title="Task Activity Logs",
        QueryLines=new []{"some valid Query lines"},
        View=LogQueryVisualizationType.TABLE,
        Region="a valid region code"
    });

    var myDashboard = new Dashboard(Scope,  "dashboard", new DashboardProps()
    {
        DashboardName="Some Name"
    
    } );
    myDashboard.AddWidgets(widgets[0][0]);

    return null;
   }

---

This is 🐛 Bug Report

[RomainMuller]

Thanks for reporting. I will have a look into this.

[github-actions]

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