So I was playing around with Sequences, and I came across a problem I haven't
been able to solve in a decent way. I’ve reduced it to a simpler example here:
let array : [Int] = [1, 2, 3]
let mapArray = array.map { $0 }
let flatArray = mapArray.flatten() // Error!
This last line of code prints the following error:
let flatArray = mapArray.flatten() // Error!
^~~~~~~~
Swift.SequenceType:4:17: note: found this candidate
public func flatten() -> FlattenSequence<Self>
^
Swift.CollectionType:4:17: note: found this candidate
public func flatten() -> FlattenCollection<Self>
^
Swift.CollectionType:4:17: note: found this candidate
public func flatten() -> FlattenBidirectionalCollection<Self>
^
As far as I understand it, the error happens because several protocols
extensions implement the `flatten` method, and `mapArray` (which is of type
`Array<Optional<Int>>`) conforms to a few of those, which means the compiler
has no way of knowing which one I intend on using.
How do I solve this?_______________________________________________
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