   @inline(__always)
   internal static func join(word: Int, bit: Int) -> Int {
     _sanityCheck(bit >= 0 && bit < Word.capacity)
-    return (word &<< Word.shift) + bit
+    return word * Word.capacity + bit
   }
 }
 

  }

  @inlinable
  internal static var shift: Int {
    @inline(__always)
    get {
      return UInt.bitWidth.trailingZeroBitCount
    }
  }

  @inlinable
  @inline(__always)
  internal func uncheckedContains(_ bit: Int) -> Bool {
    _sanityCheck(bit >= 0 && bit < UInt.bitWidth)

    // Note: We perform on UInts to get faster unsigned math (masking).
    let element = UInt(bitPattern: element)
    let capacity = UInt(bitPattern: Word.capacity)
    return Int(bitPattern: element % capacity)
  }

  @inlinable
