Specialize Symbol.hashCode

sdk/lib/internal/symbol.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart._internal;
 
 /**
  * Implementation of [core.Symbol].  This class uses the same name as
  * a core class so a user can't tell the difference.
  *
@@ skipping 94 matching lines @@
    * otherwise invalid names.
    */
   const Symbol.unvalidated(this._name);
 
   // This is called by dart2js.
   Symbol.validated(String name)
       : this._name = validatePublicSymbol(name);
 
   bool operator ==(other) => other is Symbol && _name == other._name;
 
-  int get hashCode {
-    const arbitraryPrime = 664597;
-    return 0x1fffffff & (arbitraryPrime * _name.hashCode);
-  }
+  external int get hashCode;
 
   toString() => 'Symbol("$_name")';
 
   /// Platform-private accessor which cannot be called from user libraries.
   static String getName(Symbol symbol) => symbol._name;
 
   static String validatePublicSymbol(String name) {
     if (name.isEmpty || publicSymbolPattern.hasMatch(name)) return name;
     if (name.startsWith('_')) {
       // There may be other private parts in a qualified name than the first
       // one, but this is a common case that deserves a specific error
       // message.
       throw new ArgumentError('"$name" is a private identifier');
     }
     throw new ArgumentError(
         '"$name" is not a valid (qualified) symbol name');
   }
 
   /**
    * Checks whether name is a valid symbol name.
    *
    * This test allows both private and non-private symbols.
    */
   static bool isValidSymbol(String name) {
     return (name.isEmpty || symbolPattern.hasMatch(name));
   }
 }