Eliminated the accumulated feature warnings.

No, this isn't busywork, how dare you suggest
such a thing. I intend my tombstone to say

           HERE LIES EXTEMPORE,
  WHO ELIMINATED A LOT OF SIP-18 WARNINGS
             REST IN PEACE

8 files changed, 10 insertions, 4 deletions

diff --git a/src/compiler/scala/tools/nsc/Main.scala b/src/compiler/scala/tools/nsc/Main.scala
index 9f6f483ad8..a66ee572a9 100644
--- a/src/compiler/scala/tools/nsc/Main.scala
+++ b/src/compiler/scala/tools/nsc/Main.scala
@@ -5,6 +5,8 @@
 package scala.tools
 package nsc
 
+import scala.language.postfixOps
+
 /** The main class for NSC, a compiler for the programming
  *  language Scala.
  */
diff --git a/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala b/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala
index eb31f7a66e..d22311afe9 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala
@@ -13,6 +13,7 @@ import scala.annotation.{ switch, tailrec }
 import scala.collection.{ mutable, immutable }
 import mutable.{ ListBuffer, ArrayBuffer }
 import scala.xml.Utility.{ isNameStart }
+import scala.language.postfixOps
 
 /** See Parsers.scala / ParsersCommon for some explanation of ScannersCommon.
  */
diff --git a/src/compiler/scala/tools/nsc/io/Jar.scala b/src/compiler/scala/tools/nsc/io/Jar.scala
index ee3e2b04d1..2967f67e9c 100644
--- a/src/compiler/scala/tools/nsc/io/Jar.scala
+++ b/src/compiler/scala/tools/nsc/io/Jar.scala
@@ -10,7 +10,7 @@ import java.io.{ InputStream, OutputStream, IOException, FileNotFoundException,
 import java.util.jar._
 import scala.collection.JavaConverters._
 import Attributes.Name
-import scala.language.implicitConversions
+import scala.language.{ implicitConversions, postfixOps }
 
 // Attributes.Name instances:
 //
diff --git a/src/compiler/scala/tools/nsc/transform/patmat/Solving.scala b/src/compiler/scala/tools/nsc/transform/patmat/Solving.scala
index a0fb6e82fc..3c7dc79636 100644
--- a/src/compiler/scala/tools/nsc/transform/patmat/Solving.scala
+++ b/src/compiler/scala/tools/nsc/transform/patmat/Solving.scala
@@ -8,6 +8,7 @@ package scala.tools.nsc.transform.patmat
 
 import scala.collection.mutable
 import scala.reflect.internal.util.Statistics
+import scala.language.postfixOps
 
 // naive CNF translation and simple DPLL solver
 trait Solving extends Logic {
diff --git a/src/compiler/scala/tools/nsc/typechecker/Namers.scala b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
index de3010c371..f84a758281 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Namers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
@@ -9,6 +9,7 @@ package typechecker
 import scala.collection.mutable
 import scala.annotation.tailrec
 import symtab.Flags._
+import scala.language.postfixOps
 
 /** This trait declares methods to create symbols and to enter them into scopes.
  *
diff --git a/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala b/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala
index 7e36b90b31..26b38e924a 100644
--- a/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala
@@ -9,6 +9,7 @@ package typechecker
 import scala.collection.{ mutable, immutable }
 import symtab.Flags._
 import scala.collection.mutable.ListBuffer
+import scala.language.postfixOps
 
 /** Synthetic method implementations for case classes and case objects.
  *
diff --git a/src/compiler/scala/tools/nsc/typechecker/TypeStrings.scala b/src/compiler/scala/tools/nsc/typechecker/TypeStrings.scala
index eb05486dca..afe6875218 100644
--- a/src/compiler/scala/tools/nsc/typechecker/TypeStrings.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/TypeStrings.scala
@@ -153,7 +153,7 @@ trait TypeStrings {
   private type JClass = java.lang.Class[_]
   private val ObjectClass = classOf[java.lang.Object]
   private val primitives = Set[String]("byte", "char", "short", "int", "long", "float", "double", "boolean", "void")
-  private val primitiveMap = primitives.toList map { x =>
+  private val primitiveMap = (primitives.toList map { x =>
     val key = x match {
       case "int"  => "Integer"
       case "char" => "Character"
@@ -165,7 +165,7 @@ trait TypeStrings {
     }
 
     ("java.lang." + key) -> ("scala." + value)
-  } toMap
+  }).toMap
 
   def isAnonClass(cl: Class[_]) = {
     val xs = cl.getName.reverse takeWhile (_ != '$')
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index 2ea986def7..0d619ea046 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -3963,7 +3963,7 @@ trait Typers extends Adaptations with Tags {
             case Apply(fn, args) if matches(fn)   => Some((applyOp(args), fn))
             case Assign(lhs, _) if matches(lhs)   => Some((nme.updateDynamic, lhs))
             case _ if matches(t)                  => Some((nme.selectDynamic, t))
-            case _                                => t.children flatMap findSelection headOption
+            case _                                => (t.children flatMap findSelection).headOption
           }
           findSelection(cxTree) match {
             case Some((opName, treeInfo.Applied(_, targs, _))) =>