diff options
| -rw-r--r-- | src/library/scala/collection/mutable/ListBuffer.scala | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/src/library/scala/collection/mutable/ListBuffer.scala b/src/library/scala/collection/mutable/ListBuffer.scala index b7b487964c..e059f31929 100644 --- a/src/library/scala/collection/mutable/ListBuffer.scala +++ b/src/library/scala/collection/mutable/ListBuffer.scala @@ -11,6 +11,7 @@ package scala.collection package mutable +import scala.annotation.tailrec import generic._ import immutable.{List, Nil, ::} import java.io._ @@ -178,8 +179,23 @@ final class ListBuffer[A] this } - override def ++=(xs: TraversableOnce[A]): this.type = - if (xs.asInstanceOf[AnyRef] eq this) ++= (this take size) else super.++=(xs) + private def ++=(elems: collection.LinearSeq[A]): this.type = { + @tailrec def loop(xs: collection.LinearSeq[A]) { + if (xs.nonEmpty) { + this += xs.head + loop(xs.tail) + } + } + loop(elems) + this + } + + override def ++=(xs: TraversableOnce[A]): this.type = xs match { + case x: AnyRef if x eq this => this ++= (this take size) + case xs: collection.LinearSeq[_] => this ++= xs + case _ => super.++=(xs) + + } override def ++=:(xs: TraversableOnce[A]): this.type = if (xs.asInstanceOf[AnyRef] eq this) ++=: (this take size) else super.++=:(xs) |