Clean up imports

Honor the new scheme where any explicit import of a
root import will disable the root import.

Author: odersky

compiler/src/dotty/tools/dotc/ast/Trees.scala

@@ -32,7 +32,7 @@ object Trees {
   /** Property key for trees with documentation strings attached */
   val DocComment = new Property.Key[Comment]
 
-   @sharable private var nextId = 0 // for debugging
+  @sharable private var nextId = 0 // for debugging
 
   type LazyTree = AnyRef     /* really: Tree | Lazy[Tree] */
   type LazyTreeList = AnyRef /* really: List[Tree] | Lazy[List[Tree]] */

compiler/src/dotty/tools/dotc/repl/CompilingInterpreter.scala

@@ -6,7 +6,7 @@ import java.io.{
   File, PrintWriter, PrintStream, StringWriter, Writer, OutputStream,
   ByteArrayOutputStream => ByteOutputStream
 }
-import java.lang.{Class, ClassLoader}
+import java.lang.{Class, ClassLoader, Thread, System, StringBuffer}
 import java.net.{URL, URLClassLoader}
 
 import scala.collection.immutable.ListSet

compiler/src/dotty/tools/dotc/repl/InterpreterLoop.scala

@@ -4,7 +4,7 @@ package repl
 
 import java.io.{BufferedReader, File, FileReader, PrintWriter}
 import java.io.IOException
-import java.lang.{ClassLoader, System}
+import java.lang.{ClassLoader, System, Thread}
 import scala.concurrent.{Future, Await}
 import scala.concurrent.duration.Duration
 import reporting.Reporter

compiler/src/dotty/tools/dotc/transform/CollectEntryPoints.scala

@@ -9,7 +9,6 @@ import dotty.tools.dotc.core.Symbols.NoSymbol
 import scala.annotation.tailrec
 import dotty.tools.dotc.core._
 import Symbols._
-import scala.Some
 import dotty.tools.dotc.transform.TreeTransforms.{NXTransformations, TransformerInfo, TreeTransform, TreeTransformer}
 import dotty.tools.dotc.ast.tpd
 import dotty.tools.dotc.core.Contexts.Context

compiler/src/dotty/tools/dotc/util/Chars.scala

@@ -6,7 +6,6 @@ package dotty.tools.dotc
 package util
 
 import scala.annotation.switch
-import java.lang.{ Character => JCharacter }
 import java.lang.{Character => JCharacter}
 import java.lang.Character.LETTER_NUMBER
 import java.lang.Character.LOWERCASE_LETTER
@@ -66,16 +65,16 @@ object Chars {
 
   /** Can character start an alphanumeric Scala identifier? */
   def isIdentifierStart(c: Char): Boolean =
-    (c == '_') || (c == '$') || Character.isUnicodeIdentifierStart(c)
+    (c == '_') || (c == '$') || JCharacter.isUnicodeIdentifierStart(c)
 
   /** Can character form part of an alphanumeric Scala identifier? */
   def isIdentifierPart(c: Char) =
-    (c == '$') || Character.isUnicodeIdentifierPart(c)
+    (c == '$') || JCharacter.isUnicodeIdentifierPart(c)
 
   /** Is character a math or other symbol in Unicode?  */
   def isSpecial(c: Char) = {
-    val chtp = Character.getType(c)
-    chtp == Character.MATH_SYMBOL.toInt || chtp == Character.OTHER_SYMBOL.toInt
+    val chtp = JCharacter.getType(c)
+    chtp == JCharacter.MATH_SYMBOL.toInt || chtp == JCharacter.OTHER_SYMBOL.toInt
   }
 
   private final val otherLetters = Set[Char]('\u0024', '\u005F')  // '$' and '_'