Constrain lazy elements.element == element

airspeedswift · airspeedswift · commit 5845908fa37c · 2017-05-06T14:35:48.000-07:00
diff --git a/stdlib/public/core/Flatten.swift.gyb b/stdlib/public/core/Flatten.swift.gyb
@@ -418,8 +418,7 @@ extension LazyCollectionProtocol
   Self : ${collectionForTraversal(traversal)},
   Elements : ${collectionForTraversal(traversal)},
 %   end
-  ${constraints % {'Base': 'Elements.'}},
-  Element == Elements.Element {
+  ${constraints % {'Base': 'Elements.'}} {
   /// A concatenation of the elements of `self`.
   public func joined() -> LazyCollection<${Collection}<Elements>> {
     return ${Collection}(elements).lazy
diff --git a/stdlib/public/core/LazyCollection.swift.gyb b/stdlib/public/core/LazyCollection.swift.gyb
@@ -29,7 +29,7 @@ public protocol LazyCollectionProtocol
   /// possibly with a simpler type.
   ///
   /// - See also: `elements`
-  associatedtype Elements : Collection = Self
+  associatedtype Elements : Collection = Self where Elements.Element == Element
 }
 
 /// When there's no special associated `Elements` type, the `elements`

Original file line number	Diff line number	Diff line change
`@@ -29,7 +29,7 @@ public protocol LazyCollectionProtocol`
`29`	`29`	`/// possibly with a simpler type.`
`30`	`30`	`///`
`31`	`31`	/// - See also: `elements`
`32`		`- associatedtype Elements : Collection = Self`
	`32`	`+ associatedtype Elements : Collection = Self where Elements.Element == Element`
`33`	`33`	`}`
`34`	`34`
`35`	`35`	/// When there's no special associated `Elements` type, the `elements`