Changed scala.Symbol to be always interned

3 files changed, 24 insertions, 17 deletions

diff --git a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
index cd8c084f03..04334951ec 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
@@ -615,8 +615,7 @@ trait Parsers extends NewScanners with MarkupParsers {
       if (isSymLit) {
         atPos(pos) {
           var symid = scalaDot(nme.Symbol)
-          val symobj = Apply(symid, List(t))
-          if (isPattern) symobj else Select(symobj, nme.intern)
+          Apply(symid, List(t))
         }
       } else {
         t
diff --git a/src/compiler/scala/tools/nsc/symtab/IdeSupport.scala b/src/compiler/scala/tools/nsc/symtab/IdeSupport.scala
index 097e57950b..50e72bf82f 100644
--- a/src/compiler/scala/tools/nsc/symtab/IdeSupport.scala
+++ b/src/compiler/scala/tools/nsc/symtab/IdeSupport.scala
@@ -532,7 +532,7 @@ trait IdeSupport extends SymbolTable { // added to global, not analyzers.
     case _ : Float => 0 : Float
     case _ : Double => 0 : Double
     case _ : String => "string"
-    case _ : scala.Symbol => 'symbol
+    case _ : scala.Symbol => Symbol("symbol")
     case value => value
     }))
   }
@@ -581,4 +581,4 @@ trait IdeSupport extends SymbolTable { // added to global, not analyzers.
   case _ => tree
   }).setPos(tree.pos)
 
-}
\ No newline at end of file
+}
diff --git a/src/library/scala/Symbol.scala b/src/library/scala/Symbol.scala
index 2c951a4619..e9f5b08a56 100644
--- a/src/library/scala/Symbol.scala
+++ b/src/library/scala/Symbol.scala
@@ -13,13 +13,12 @@ package scala
 
 import scala.collection.jcl
 
-private[scala] object internedSymbols extends jcl.WeakHashMap[Symbol, ref.WeakReference[Symbol]]
+private[scala] object internedSymbols extends jcl.WeakHashMap[String, ref.WeakReference[Symbol]]
 
 /** <p>
  *    This class provides a simple way to get unique objects for
- *    equal strings. By default, symbols use string equality for
- *    equality testing, but interned symbols can be compared using
- *    reference equality for the same effect. Instances of
+ *    equal strings. Since symbols are interned, they can be compared using
+ *    reference equality. Instances of
  *    <code>Symbol</code> can be created easily with Scala's built-in
 *     quote mechanism.
  *  </p>
@@ -27,13 +26,13 @@ private[scala] object internedSymbols extends jcl.WeakHashMap[Symbol, ref.WeakRe
  *    For instance, the <a href="http://scala-lang.org/" target="_top">Scala</a>
  *    term <code>'mysym</code> will invoke the constructor of the
  *    <code>Symbol</code> class in the following way:
- *    <code>new Symbol("mysym").intern</code>.
+ *    <code>Symbol("mysym")</code>.
  *  </p>
  *
- *  @author  Martin Odersky
- *  @version 1.7, 08/12/2003
+ *  @author  Martin Odersky, Iulian Dragos
+ *  @version 1.8
  */
-final case class Symbol(name: String) {
+final class Symbol private (val name: String) {
 
   /** Converts this symbol to a string.
    */
@@ -41,6 +40,10 @@ final case class Symbol(name: String) {
     "'" + name
   }
 
+}
+
+object Symbol {
+
   /** <p>
    *    Makes this symbol into a unique reference.
    *  </p>
@@ -49,12 +52,17 @@ final case class Symbol(name: String) {
    *    then they must be identical (wrt reference equality).
    *  </p>
    *
-   *  @return the unique reference to this symbol.
+   *  @return the unique reference to this string.
    */
-  def intern: Symbol = internedSymbols.synchronized {
-    internedSymbols.get(this).map(_.get).getOrElse(None) match {
+  def apply(name: String): Symbol = internedSymbols.synchronized {
+    internedSymbols.get(name).map(_.get).getOrElse(None) match {
     case Some(sym) => sym
     case _ =>
-      internedSymbols(this) = new ref.WeakReference(this); this
-  } }
+      val sym = new Symbol(name)
+      internedSymbols(name) = new ref.WeakReference(sym)
+      sym
+    }
+  }
+
+  def unapply(other: Symbol): Option[String] = Some(other.name)
 }