context.RegisterCompilationStartAction(context =>
{
    var notifyDataErrorInfoAttributeSymbol = context.Compilation.GetTypeByMetadataName("CommunityToolkit.Mvvm.ComponentModel.NotifyDataErrorInfoAttribute");
    if (notifyDataErrorInfoAttributeSymbol is null)
    {
        return;
    }

    context.RegisterSymbolAction(context =>
    {
        // Logic goes here.
    }
}