Merge pull request scala/scala#8744 from som-snytt/review/noise

Noise reduction

Author: som-snytt

library/src/scala/collection/immutable/LongMap.scala

@@ -18,7 +18,6 @@ import java.lang.IllegalStateException
 import scala.collection.generic.{BitOperations, DefaultSerializationProxy}
 import scala.collection.mutable.{Builder, ImmutableBuilder, ListBuffer}
 import scala.annotation.tailrec
-import scala.annotation.tailrec
 import scala.annotation.unchecked.uncheckedVariance
 
 /** Utility class for long maps.

library/src/scala/collection/mutable/ListBuffer.scala

@@ -15,7 +15,6 @@ package mutable
 
 import scala.annotation.tailrec
 import scala.collection.immutable.{List, Nil, ::}
-import scala.annotation.tailrec
 import java.lang.{IllegalArgumentException, IndexOutOfBoundsException}
 import scala.collection.generic.DefaultSerializable
 import scala.runtime.Statics.releaseFence

library/src/scala/collection/mutable/StringBuilder.scala

@@ -23,7 +23,7 @@ import scala.Predef.{ // unimport char-related implicit conversions to avoid tri
   genericWrapArray => _,
   wrapCharArray => _,
   wrapString => _,
-  _
+  //_
 }
 
 /** A builder for mutable sequence of characters.  This class provides an API

library/src/scala/runtime/NonLocalReturnControl.scala

@@ -10,11 +10,11 @@
  * additional information regarding copyright ownership.
  */
 
-package scala
-package runtime
+package scala.runtime
 
 import scala.util.control.ControlThrowable
 
-class NonLocalReturnControl[@specialized T](val key: AnyRef, val value: T) extends ControlThrowable {
+// remove Unit specialization when binary compatibility permits
+class NonLocalReturnControl[@specialized(Byte, Short, Int, Long, Char, Float, Double, Boolean, Unit) T](val key: AnyRef, val value: T) extends ControlThrowable {
   final override def fillInStackTrace(): Throwable = this
 }