Fix "is Object" to always be true in Dart.

frog/value.dart

 // Copyright (c) 2011, 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.
 
 /**
  * Represents a meta-value for code generation.
  */
 class Value {
   /** The [Type] of the [Value]. */
   Type type;
@@ skipping 373 matching lines @@
    *
    * - If a primitive type, then uses the JavaScript typeof.
    * - If it's a non-generic class, use instanceof.
    * - Otherwise add a fake member to test for.  This value is generated
    *   as a function so that it can be called for a runtime failure.
    */
   Value instanceOf(MethodGenerator context, Type toType, SourceSpan span,
       [bool isTrue=true, bool forceCheck=false]) {
     // TODO(jimhug): Optimize away tests that will always pass unless
     //    forceCheck is true.
+
     if (toType.isVar) {
       world.error('can not resolve type', span);
-      return new EvaluatedValue(world.nonNullBool, true, 'true', null);
-    }
-
-    if (toType is ParameterType) {
-      return new EvaluatedValue(world.nonNullBool, true, 'true', null);
     }
 
     String testCode = null;
+    if (toType.isVar || toType.isObject || toType is ParameterType) {
+      // Note: everything is an Object, including null.
+      if (needsTemp) {
+        return new Value(world.nonNullBool, '($code, true)', span);

[Siggi Cherem (dart-lang), 2011/11/17 16:55:57]

can you explain to me a bit more ($code, true)? is this so that we get the side
effects, then return true?

[Jennifer Messerly, 2011/11/17 18:18:51]

Yes, exactly.

+      } else {
+        return new EvaluatedValue(world.nonNullBool, true, 'true', null);
+      }
+    }
+
     if (toType.library.isCore) {
       var typeofName = toType.typeofName;
       if (typeofName != null) {
         testCode = "(typeof($code) ${isTrue ? '==' : '!='} '$typeofName')";
       }
     }
     if (toType.isClass && toType is !ConcreteType) {
       toType.markUsed();
       testCode = '($code instanceof ${toType.jsname})';
       if (!isTrue) {
@@ skipping 280 matching lines @@
 
     // Then look for members in my library.
     member = home.library.lookup(name, span);
     if (member != null) {
       return member;
     }
 
     return null;
   }
 }