This unit test works when you declare the type as int[], but not when you declare the type as IList<int>.

I believe this also affects LINQ expressions using Contains or In. IEnumerable, array types, and List types are supported but IList throws an Unsupported exception.

[Test]
public void TestInExpressionWithIList()
{
    IList<int> list = new[] { 2, 4, 6 };
    var query = Query<A>.Where(a => list.Contains(a.X));
    var expected = "{ \"x\" : { \"$in\" : [2, 4, 6] } }";
    Assert.AreEqual(expected, query.ToJson());
}