Problems with F#

[francotiveron]

Does it works with F#?
this code

            db().Positions
                .Upsert(Position(BookId = _books[sourceBook].BookId, InstrumentId = instrumentId))
                .On(fun p -> {| BookId = p.BookId; InstrumentId = p.InstrumentId |})
                .WhenMatched(fun p -> 
                    Position(
                        BookId = destBookId,
                        InstrumentId = p.InstrumentId,
                        Time = p.Time,
                        Value = p.Value,
                        Book = p.Book))
                .RunAsync()

throws this exception at runtime

System.NotSupportedException: Could not convert the following F# Quotation to a LINQ Expression Tree

Sequential (Sequential (Sequential (Sequential (Sequential (Sequential (Value (),
PropertySet (Some (returnVal),
BookId,
[ValueWithName (2,
destBookId)])),
PropertySet (Some (returnVal),
InstrumentId,
[PropertyGet (Some (p),
InstrumentId,
[])])),
PropertySet (Some (returnVal),
Time,
[PropertyGet (Some (p),
Time,
[])])),
PropertySet (Some (returnVal), Value,
[PropertyGet (Some (p), Value,
[])])),
PropertySet (Some (returnVal), Book,
[PropertyGet (Some (p), Book, [])])),
returnVal)