Make hashCode a getter and not a method.

lib/compiler/implementation/universe/universe.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.
 
 library universe;
 
 import '../closure.dart';
 import '../elements/elements.dart';
 import '../dart2jslib.dart';
 import '../runtime_types.dart';
@@ skipping 196 matching lines @@
   bool isIndex() => identical(kind, SelectorKind.INDEX) && argumentCount == 1;
   bool isIndexSet() => identical(kind, SelectorKind.INDEX) && argumentCount == 2;
 
   bool isOperator() => identical(kind, SelectorKind.OPERATOR);
   bool isUnaryOperator() => isOperator() && argumentCount == 0;
   bool isBinaryOperator() => isOperator() && argumentCount == 1;
 
   /** Check whether this is a call to 'assert'. */
   bool isAssert() => isCall() && identical(name.stringValue, "assert");
 
-  int hashCode() => argumentCount + 1000 * namedArguments.length;
+  int get hashCode => argumentCount + 1000 * namedArguments.length;
   int get namedArgumentCount => namedArguments.length;
   int get positionalArgumentCount => argumentCount - namedArgumentCount;
   DartType get receiverType => null;
 
   bool applies(Element element, Compiler compiler)
       => appliesUntyped(element, compiler);
 
   bool appliesUntyped(Element element, Compiler compiler) {
     if (element.isSetter()) return isSetter();
     if (element.isGetter()) return isGetter() || isCall();
@@ skipping 301 matching lines @@
 
     if (!self.isInterface() && self.isSubclassOf(other)) {
       // Resolve an invocation of [element.name] on [self]. If it
       // is found, this selector is a candidate.
       return hasElementIn(self, element) && appliesUntyped(element, compiler);
     }
 
     return false;
   }
 }