   // FIXME: swift-3-indexing-model: tests for traps.
   _precondition(start <= end, "Can't form Range with end < start")
   _precondition(endPlusOne > end, "Range end has no valid successor")
-  return RangeOfStrideable(lowerBound: start, upperBound: endPlusOne)
+  return RangeOfStrideable(_uncheckedBounds: (lower: start, upper: endPlusOne))
 }
 
 @warn_unused_result

  /// A textual representation of `self`, suitable for debugging.
  public var debugDescription: String {
    return "RangeOfStrideable(\(String(reflecting: lowerBound))..<\(String(reflecting: upperBound)))"
  }
}



  @inline(__always)
  public init(_ other: Self) {
    self = other
  }
  
  @inline(__always)
