Add VersionRange.hashCode.

lib/src/version_range.dart

 // Copyright (c) 2014, 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.
 
 library pub_semver.src.version_range;
 
 import 'version.dart';
 import 'version_constraint.dart';
 
 /// Constrains versions to a fall within a given range.
@@ skipping 48 matching lines @@
 
   bool operator ==(other) {
     if (other is! VersionRange) return false;
 
     return min == other.min &&
            max == other.max &&
            includeMin == other.includeMin &&
            includeMax == other.includeMax;
   }
 
+  int get hashCode => min.hashCode ^ (max.hashCode * 3) ^
+      (includeMin.hashCode * 5) ^ (includeMax.hashCode * 7);

[Bob Nystrom, 2014/10/30 16:45:24]

Idle thought: these multiplications can push the result to a bigint. Do we care
about that?

+
   bool get isEmpty => false;
 
   bool get isAny => min == null && max == null;
 
   /// Tests if [other] falls within this version range.
   bool allows(Version other) {
     if (min != null) {
       if (other < min) return false;
       if (!includeMin && other == min) return false;
     }
@@ skipping 91 matching lines @@
     if (max != null) {
       if (min != null) buffer.write(' ');
       buffer.write(includeMax ? '<=' : '<');
       buffer.write(max);
     }
 
     if (min == null && max == null) buffer.write('any');
     return buffer.toString();
   }
 }