 /// Return `true` iff an element in `seq` satisfies `predicate`.
 public func contains<
   S : SequenceType, L : BooleanType
->(seq: S, predicate: (S.Generator.Element)->L) -> Bool {
+>(seq: S, @noescape predicate: S.Generator.Element -> L) -> Bool {
   for a in seq {
     if predicate(a) {
       return true

  where
    S0.Generator.Element == S1.Generator.Element
>(s: S0, prefix: S1,
  isEquivalent: (S1.Generator.Element, S1.Generator.Element) -> Bool) -> Bool
{
  var prefixGenerator = prefix.generate()


  where
    S1.Generator.Element == S2.Generator.Element
>(a1: S1, a2: S2,
  @noescape isEquivalent: (S1.Generator.Element, S1.Generator.Element) -> Bool)
  -> Bool
{
  var g1 = a1.generate()
  var g2 = a2.generate()
