Support nested types in DataTemplate.DataType

Currently TypeResolver goes crazy - raises exception (for 0.8.x version [clarification: only for F# modules that don’t have namespace]) and gives error in compile time from the master branch.

Just to show some sample. This kind of code is perfectly valid in WPF:

        <ItemsControl ItemsSource="{Binding Items}">
            <ItemsControl.ItemTemplate>
                <DataTemplate DataType="{x:Type local:SomeClass+Data}">
                    <TextBlock Text="{Binding Value}" />
                </DataTemplate>
            </ItemsControl.ItemTemplate>
        </ItemsControl>

    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            DataContext = this;
        }

        public IEnumerable<Data> Items { get => Enumerable.Range(0, 10).Select(_ => new Data()); }
    }

    public static class SomeClass
    {
        public class Data
        {
            public string Value { get; } = "Hello World";
        }
    }

While this is a rare use-case for C# in F# world it’s common. Instead (or additional to) of using namespace, types are grouped in modules, like this:

module Test = 
    type SomeType = { Id : int; Value : string }

So I think it would be very nice to have support for this scenario.

[grokys]

Investigating this now, looks like this works fine in unit tests, which makes it harder to fix…

Update: yep, seems to be our Mono.Cecil backend that’s not handling this correctly.

[BAndysc]

+1, it prevents from using CompiledBindings in few places 😦