num implements Comparable and Hashable.

lib/compiler/implementation/lib/js_helper.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('dart:_js_helper');
 
 #import('coreimpl.dart');
 
 #source('constant_map.dart');
 #source('native_helper.dart');
@@ skipping 1095 matching lines @@
 callTypeCast(value, property) {
   if (value === null
       || ((JS('bool', 'typeof # === "object"', value))
           && JS('bool', '#[#]()', value, property))) {
     return value;
   }
   propertyTypeCastError(value, property);
 }
 
 /**
+ * Specialization of the type check for num and String and their
+ * supertype since [value] can be a JS primitive.
+ */
+numberOrStringSuperTypeCheck(value, property) {
+  if (value === null) return value;
+  if (value is String) return value;
+  if (value is num) return value;
+  if (JS('bool', '!!#[#]', value, property)) return value;
+  propertyTypeError(value, property);
+}
+
+numberOrStringSuperTypeCast(value, property) {
+  if (value is String) return value;
+  if (value is num) return value;
+  return propertyTypeCast(value, property);
+}
+
+numberOrStringSuperNativeTypeCheck(value, property) {
+  if (value === null) return value;
+  if (value is String) return value;
+  if (value is num) return value;
+  if (JS('bool', '#[#]()', value, property)) return value;
+  propertyTypeError(value, property);
+}
+
+numberOrStringSuperNativeTypeCast(value, property) {
+  if (value === null) return value;
+  if (value is String) return value;
+  if (value is num) return value;
+  if (JS('bool', '#[#]()', value, property)) return value;
+  propertyTypeCastError(value, property);
+}
+
+/**
  * Specialization of the type check for String and its supertype
  * since [value] can be a JS primitive.
  */
 stringSuperTypeCheck(value, property) {
   if (value === null) return value;
   if (value is String) return value;
   if (JS('bool', '!!#[#]', value, property)) return value;
   propertyTypeError(value, property);
 }
 
@@ skipping 103 matching lines @@
   throw new NoSuchMethodException(obj, name, arguments);
 }
 
 /**
  * Called by generated code when a static field's initializer references the
  * field that is currently being initialized.
  */
 void throwCyclicInit(String staticName) {
   throw new RuntimeError("Cyclic initialization for static $staticName");
 }