Merge pull request #9378 from airspeedswift/lazy-constraints

Author: swift-ci

stdlib/public/core/Flatten.swift.gyb

@@ -133,10 +133,7 @@ extension Sequence where Iterator.Element : Sequence {
   }
 }
 
-extension LazySequenceProtocol
-  where
-  Elements.Iterator.Element == Iterator.Element,
-  Iterator.Element : Sequence {
+extension LazySequenceProtocol where Iterator.Element : Sequence {
 
   /// Returns a lazy sequence that concatenates the elements of this sequence of
   /// sequences.
@@ -418,8 +415,8 @@ extension LazyCollectionProtocol
   Self : ${collectionForTraversal(traversal)},
   Elements : ${collectionForTraversal(traversal)},
 %   end
-  ${constraints % {'Base': 'Elements.'}},
-  Iterator.Element == Elements.Iterator.Element {
+  ${constraints % {'Base': 'Elements.'}}
+{
   /// A concatenation of the elements of `self`.
   public func joined() -> LazyCollection<${Collection}<Elements>> {
     return ${Collection}(elements).lazy

stdlib/public/core/LazySequence.swift

@@ -133,6 +133,7 @@ public protocol LazySequenceProtocol : Sequence {
   ///
   /// - See also: `elements`
   associatedtype Elements : Sequence = Self
+  where Elements.Iterator.Element == Iterator.Element
 
   /// A sequence containing the same elements as this one, possibly with
   /// a simpler type.