InvalidOperationException when using Distinct in LINQ

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    • Type: Bug
    • Resolution: Fixed
    • Priority: Major - P3
    • 2.14.0
    • Affects Version/s: 2.10.0, 2.11.2
    • Component/s: LINQ
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      I have a code like this in my ASP.NET Core app

      var evtQry = from pe in EventDocCollection.AsQueryable()
                    where pe.Create.User.Id == user.Id
                    orderby pe.DateTime descending
                    select pe.Id;
var eventIds = await evtQry.Distinct().Take(20).ToListAsync();

      and it throws the following exception when executed:

      System.InvalidOperationException: Extension node must override the property Expression.Type.
   at System.Linq.Expressions.Expression.get_Type()
   at MongoDB.Driver.Linq.Expressions.GroupByExpression..ctor(Expression source, Expression keySelector)
   at MongoDB.Driver.Linq.Processors.Pipeline.MethodCallBinders.DistinctBinder.Bind(PipelineExpression pipeline, PipelineBindingContext bindingContext, MethodCallExpression node, IEnumerable`1 arguments)
   at MongoDB.Driver.Linq.Processors.MethodInfoMethodCallBinder`1.Bind(PipelineExpression pipeline, TBindingContext bindingContext, MethodCallExpression node, IEnumerable`1 arguments)
   at MongoDB.Driver.Linq.Processors.PipelineBinderBase`1.BindMethodCall(MethodCallExpression node)

      Do you have any idea why this exception is thrown? It looks like a problem with the C# driver. 

            Assignee:
            James Kovacs
            Reporter:
            Serghei Sarafudinov
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              Created:
              Updated:
              Resolved: