RSRP-289033: False xaml error in indexed binding path to static object.

Resharper incorrectly reports an error for the path on a binding when the following conditions are met:

• The source of the binding is be a property on a static instance.
  
• The path must be a 2 parameter indexer.
  
• There must not be a single parameter indexer defined.

When all of these conditions are met, the path will be reported as a "Parameter count mismatch" but the code executes correctly when run.

We use this pattern in quite a few places in our code and it requires that the whole team constantly sets these errors to "ignored".

I have a very small solution which demonstrates this problem easily. Here is some sample code:

// Static data class
namespace ResharperIndexerErrorDemo
{
    public class Data
    {
        public static Data Instance { get; set; }

        static Data()
        {
            Instance = new Data();
        }

        public string this[string key, string defaultValue]
        {
            get
            {
                if (key == "foo")
                {
                    return "bar";
                }
                return defaultValue;
            }
        }
    }
}

<!– Sample window xaml –>
<Window x:Class="ResharperIndexerErrorDemo.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:ResharperIndexerErrorDemo"
    Title="MainWindow" Height="350" Width="525">
    <StackPanel>
        <!– The path on these two text blocks have the resharper error "Parameter count mismatch" –>
        <TextBlock Text="{Binding Source={x:Static local:Data.Instance}, Path=[foo\, unused]}"/>
        <TextBlock Text="{Binding Source={x:Static local:Data.Instance}, Path=[test\, used!]}"/>
    </StackPanel>
</Window>

// Sample window cs
using System.Windows;

namespace ResharperIndexerErrorDemo
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }
    }
}