Override ArrayDeque.head to avoid iterator allocation

retronym · retronym · commit 093d26aa9916 · 2019-10-23T18:00:00.000+10:00
diff --git a/src/library/scala/collection/mutable/ArrayDeque.scala b/src/library/scala/collection/mutable/ArrayDeque.scala
@@ -88,6 +88,8 @@ class ArrayDeque[A] protected (
     prependAssumingCapacity(elem)
   }
 
+  override def head: A = apply(0)
+
   @inline private[ArrayDeque] def appendAssumingCapacity(elem: A): this.type = {
     array(end) = elem.asInstanceOf[AnyRef]
     end = end_+(1)

Original file line number	Diff line number	Diff line change
`@@ -88,6 +88,8 @@ class ArrayDeque[A] protected (`
`88`	`88`	`prependAssumingCapacity(elem)`
`89`	`89`	`}`
`90`	`90`
	`91`	`+ override def head: A = apply(0)`
	`92`	`+`
`91`	`93`	`@inline private[ArrayDeque] def appendAssumingCapacity(elem: A): this.type = {`
`92`	`94`	`array(end) = elem.asInstanceOf[AnyRef]`
`93`	`95`	`end = end_+(1)`