MongoDB.Driver.Linq.ExpressionNotSupportedException: Expression not supported: x.Dict.get_Item("test").    at MongoDB.Driver.Linq.Linq3Implementation.Translators.ExpressionToAggregationExpressionTranslators.MethodTranslators.GetItemMethodToAggregationExpressionTranslator.Translate(TranslationContext context, MethodCallExpression expression)

using MongoDB.Driver;
using MongoDB.Driver.Linq;

var Query = (LinqProvider provider) =>
{
    var connectionstring = "mongodb://docker:mongopw@localhost:49153";
    var settings = MongoClientSettings.FromConnectionString(connectionstring);
    settings.LinqProvider = provider;
    var client = new MongoClient(settings);
    var db = client.GetDatabase("db1");
    var collection = db.GetCollection<ExampleClass>("collection1");
    return collection.AsQueryable().Select(x => x.Dict["test"]).First();
};

Console.WriteLine(Query(LinqProvider.V2)); // Works
Console.WriteLine(Query(LinqProvider.V3)); // Throws exception

class ExampleClass
{
    public IDictionary<string, int> Dict { get; set; }
}