Update scala to 2.12.6 and some cleaning up

build.sbt

@@ -2,7 +2,7 @@ import ScalaModulePlugin._
 
 scalaVersionsByJvm in ThisBuild := {
   val v211 = "2.11.12"
-  val v212 = "2.12.4"
+  val v212 = "2.12.6"
   val v213 = "2.13.0-M3"
 
   Map(

js/src/main/scala/scala/util/parsing/input/PositionCache.scala

@@ -1,6 +1,5 @@
 package scala.util.parsing.input
 
-import java.lang.CharSequence
 import java.util.{AbstractMap, Collections}
 
 private[input] trait PositionCache {

jvm/src/main/scala/scala/util/parsing/input/PositionCache.scala

@@ -1,6 +1,5 @@
 package scala.util.parsing.input
 
-import java.lang.{CharSequence, ThreadLocal}
 import java.util.WeakHashMap
 
 /**

jvm/src/test/scala/scala/util/parsing/combinator/t4929.scala

@@ -1,6 +1,6 @@
 import scala.util.parsing.json._
 import java.util.concurrent._
-import collection.JavaConversions._
+import collection.JavaConverters._
 
 import org.junit.Test
 
@@ -36,6 +36,6 @@ class t4929 {
       thread.setDaemon(true)
       thread.start()
     }
-    errors foreach { throw(_) }
+    errors.asScala foreach { throw(_) }
   }
 }

project/plugins.sbt

@@ -1,3 +1,3 @@
-addSbtPlugin("org.scala-lang.modules" % "sbt-scala-module" % "1.0.13")
+addSbtPlugin("org.scala-lang.modules" % "sbt-scala-module" % "1.0.14")
 
-addSbtPlugin("org.scala-js"     % "sbt-scalajs"              % "0.6.22")
+addSbtPlugin("org.scala-js" % "sbt-scalajs" % "0.6.22")

shared/src/main/scala/scala/util/parsing/combinator/RegexParsers.scala

@@ -10,7 +10,6 @@
 package scala
 package util.parsing.combinator
 
-import java.util.regex.Pattern
 import scala.util.matching.Regex
 import scala.util.parsing.input._
 import scala.language.implicitConversions

shared/src/main/scala/scala/util/parsing/input/OffsetPosition.scala

@@ -10,8 +10,6 @@ package scala
 package util.parsing.input
 
 import scala.collection.mutable.ArrayBuffer
-import java.lang.{CharSequence, ThreadLocal}
-import java.util.WeakHashMap
 
 /** `OffsetPosition` is a standard class for positions
  *   represented as offsets into a source ``document''.

shared/src/main/scala/scala/util/parsing/input/StreamReader.scala

@@ -9,8 +9,6 @@
 package scala
 package util.parsing.input
 
-import java.io.BufferedReader
-
 /** An object to create a `StreamReader` from a `java.io.Reader`.
  *
  * @author Miles Sabin

shared/src/test/scala/scala/util/parsing/combinator/UnitTestIO.scala

@@ -17,7 +17,6 @@ class UnitTestIO {
     val expected = "a" -> "\""
 
     val parsed = scala.util.parsing.json.JSON.parseFull(test)
-    val result = parsed == Some(Map(expected))
     assertEquals(Some(Map(expected)), parsed)
   }
 
@@ -29,4 +28,4 @@ class UnitTestIO {
     f.copyToBuffer(b)
     assertEquals(new String(b.toArray), s)
   }
-}
+}

shared/src/test/scala/scala/util/parsing/combinator/gh56.scala

@@ -1,10 +1,11 @@
 package scala.util.parsing.combinator
 
+import scala.language.postfixOps
+import scala.util.parsing.combinator.syntactical.StandardTokenParsers
+
 import org.junit.Assert.{assertEquals, assertTrue}
 import org.junit.Test
 
-import scala.util.parsing.combinator.syntactical.StandardTokenParsers
-
 /**
   * Test for issue 56: https://github.com/scala/scala-parser-combinators/issues/56
   *

shared/src/test/scala/scala/util/parsing/combinator/t1100.scala

@@ -1,11 +1,6 @@
 import scala.util.parsing.combinator.Parsers
 import scala.util.parsing.input.CharSequenceReader
 
-import java.io.{File,StringReader}
-
-import scala.util.parsing.combinator.Parsers
-import scala.util.parsing.input.{CharArrayReader, StreamReader}
-
 import org.junit.Test
 import org.junit.Assert.assertEquals
 

shared/src/test/scala/scala/util/parsing/combinator/t5514.scala

@@ -1,4 +1,3 @@
-import scala.io.Source
 import scala.util.parsing.combinator.Parsers
 import scala.util.parsing.input.Reader
 import scala.util.parsing.input.Position