Stop using the Hashable interface.

pkg/logging/lib/logging.dart

 // Copyright (c) 2012, 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.
 
 /**
  * Provides APIs for debugging and error logging. This library introduces
  * abstractions similar to those used in other languages, such as the Closure JS
  * Logger and java.util.logging.Logger.
  */
 #library('logging');
@@ skipping 229 matching lines @@
  * levels above certain [Level]. [Level]s are ordered using an integer
  * value [Level.value]. The predefined [Level] constants below are sorted as
  * follows (in descending order): [Level.SHOUT], [Level.SEVERE],
  * [Level.WARNING], [Level.INFO], [Level.CONFIG], [Level.FINE], [Level.FINER],
  * [Level.FINEST], and [Level.ALL].
  *
  * We recommend using one of the predefined logging levels. If you define your
  * own level, make sure you use a value between those used in [Level.ALL] and
  * [Level.OFF].
  */
-class Level implements Comparable, Hashable {
+class Level implements Comparable {
 
   // TODO(sigmund): mark name/value as 'const' when the language supports it.
   final String name;
 
   /**
    * Unique value for this level. Used to order levels, so filtering can exclude
    * messages whose level is under certain value.
    */
   final int value;
 
@@ skipping 64 matching lines @@
 
   /** Associated exception message (if any) when recording errors messages. */
   String exceptionText;
 
   LogRecord(
       this.level, this.message, this.loggerName,
       [time, this.exception, this.exceptionText]) :
     this.time = (time == null) ? new Date.now() : time,
     this.sequenceNumber = LogRecord._nextNumber++;
 }