Make hashCode a getter and not a method.

lib/compiler/implementation/typechecker.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.
 
 class TypeCheckerTask extends CompilerTask {
   TypeCheckerTask(Compiler compiler) : super(compiler);
   String get name => "Type checker";
 
   static const bool LOG_FAILURES = false;
 
@@ skipping 44 matching lines @@
 
 class TypeVariableType implements DartType {
   final TypeVariableElement element;
 
   TypeVariableType(this.element);
 
   SourceString get name => element.name;
 
   DartType unalias(Compiler compiler) => this;
 
-  int hashCode() => 17 * element.hashCode();
+  int get hashCode => 17 * element.hashCode;
 
   bool operator ==(other) {
     if (other is !TypeVariableType) return false;
     return identical(other.element, element);
   }
 
   String toString() => name.slowToString();
 }
 
 /**
@@ skipping 11 matching lines @@
   static const NOT_RETURNING = const StatementType('<not returning>');
   static const MAYBE_RETURNING = const StatementType('<maybe returning>');
 
   /** Combine the information about two control-flow edges that are joined. */
   StatementType join(StatementType other) {
     return (identical(this, other)) ? this : MAYBE_RETURNING;
   }
 
   DartType unalias(Compiler compiler) => this;
 
-  int hashCode() => 17 * stringName.hashCode();
+  int get hashCode => 17 * stringName.hashCode;
 
   bool operator ==(other) {
     if (other is !StatementType) return false;
     return other.stringName == stringName;
   }
 
   String toString() => stringName;
 }
 
 class VoidType implements DartType {
   const VoidType(this.element);
   SourceString get name => element.name;
   final VoidElement element;
 
   DartType unalias(Compiler compiler) => this;
 
-  int hashCode() => 1729;
+  int get hashCode => 1729;
 
   bool operator ==(other) => other is VoidType;
 
   String toString() => name.slowToString();
 }
 
 class InterfaceType implements DartType {
   final Element element;
   final Link<DartType> arguments;
 
   const InterfaceType(this.element,
                       [this.arguments = const Link<DartType>()]);
 
   SourceString get name => element.name;
 
   DartType unalias(Compiler compiler) => this;
 
   String toString() {
     StringBuffer sb = new StringBuffer();
     sb.add(name.slowToString());
     if (!arguments.isEmpty()) {
       sb.add('<');
       arguments.printOn(sb, ', ');
       sb.add('>');
     }
     return sb.toString();
   }
 
-  int hashCode() {
-    int hash = element.hashCode();
+  int get hashCode {
+    int hash = element.hashCode;
     for (Link<DartType> arguments = this.arguments;
          !arguments.isEmpty();
          arguments = arguments.tail) {
-      int argumentHash = arguments.head != null ? arguments.head.hashCode() : 0;
+      int argumentHash = arguments.head != null ? arguments.head.hashCode : 0;
       hash = 17 * hash + 3 * argumentHash;
     }
     return hash;
   }
 
   bool operator ==(other) {
     if (other is !InterfaceType) return false;
     if (!identical(element, other.element)) return false;
     return arguments == other.arguments;
   }
@@ skipping 28 matching lines @@
     return arity;
   }
 
   void initializeFrom(FunctionType other) {
     assert(returnType == null);
     assert(parameterTypes == null);
     returnType = other.returnType;
     parameterTypes = other.parameterTypes;
   }
 
-  int hashCode() {
-    int hash = 17 * element.hashCode() + 3 * returnType.hashCode();
+  int get hashCode {
+    int hash = 17 * element.hashCode + 3 * returnType.hashCode;
     for (Link<DartType> parameters = parameterTypes;
          !parameters.isEmpty();
         parameters = parameters.tail) {
-      hash = 17 * hash + 3 * parameters.head.hashCode();
+      hash = 17 * hash + 3 * parameters.head.hashCode;
     }
     return hash;
   }
 
   bool operator ==(other) {
     if (other is !FunctionType) return false;
     return returnType == other.returnType
            && parameterTypes == other.parameterTypes;
   }
 }
@@ skipping 17 matching lines @@
     StringBuffer sb = new StringBuffer();
     sb.add(name.slowToString());
     if (!typeArguments.isEmpty()) {
       sb.add('<');
       typeArguments.printOn(sb, ', ');
       sb.add('>');
     }
     return sb.toString();
   }
 
-  int hashCode() => 17 * element.hashCode();
+  int get hashCode => 17 * element.hashCode;
 
   bool operator ==(other) {
     if (other is !TypedefType) return false;
     if (!identical(element, other.element)) return false;
     return typeArguments == other.typeArguments;
   }
 }
 
 class Types {
   final Compiler compiler;
@@ skipping 732 matching lines @@
   }
 
   DartType visitStatement(Statement node) {
     compiler.unimplemented('visitNode', node: node);
   }
 
   DartType visitStringNode(StringNode node) {
     compiler.unimplemented('visitNode', node: node);
   }
 }