Fix equality of implicit closures in the Dart VM.

runtime/vm/class_finalizer.cc

 // Copyright (c) 2013, 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.
 
 #include "vm/class_finalizer.h"
 
 #include "vm/flags.h"
 #include "vm/heap.h"
 #include "vm/isolate.h"
 #include "vm/longjump.h"
@@ skipping 1522 matching lines @@
     GrowableArray<intptr_t> visited_aliases;
     if (!IsAliasCycleFree(cls, &visited_aliases)) {
       const String& name = String::Handle(cls.Name());
       const Script& script = Script::Handle(cls.script());
       ReportError(Error::Handle(),  // No previous error.
                   script, cls.token_pos(),
                   "typedef '%s' illegally refers to itself",
                   name.ToCString());
     }
     cls.set_is_type_finalized();
-    // Signature classes extend Object. No need to add this class to the direct
-    // subclasses of Object.
-    ASSERT(super_type.IsNull() || super_type.IsObjectType());
 
     // The type parameters of signature classes may have bounds.
     FinalizeUpperBounds(cls);
 
     // Resolve and finalize the result and parameter types of the signature
     // function of this signature class.
     const Function& sig_function = Function::Handle(cls.signature_function());
     ResolveAndFinalizeSignature(cls, sig_function);
 
     // Resolve and finalize the signature type of this signature class.
@@ skipping 371 matching lines @@
       CLASS_LIST_TYPED_DATA(DO_NOT_EXTEND_TYPED_DATA_CLASSES)
 #undef DO_NOT_EXTEND_TYPED_DATA_CLASSES
       case kByteDataViewCid:
       case kWeakPropertyCid:
         is_error = true;
         break;
       default: {
         // Special case: classes for which we don't have a known class id.
         if (super_type.IsDoubleType() ||
             super_type.IsIntType() ||
-            super_type.IsStringType() ||
-            super_type.IsFunctionType()) {
+            super_type.IsStringType()) {
           is_error = true;
         }
         break;
       }
     }
     if (is_error) {
       const Script& script = Script::Handle(cls.script());
       ReportError(Error::Handle(),  // No previous error.
                   script, cls.token_pos(),
                   "'%s' is not allowed to extend '%s'",
@@ skipping 29 matching lines @@
     // Verify that unless cls belongs to core lib, it cannot extend or implement
     // any of bool, num, int, double, String, Function, dynamic.
     // The exception is signature classes, which are compiler generated and
     // represent a function type, therefore implementing the Function interface.
     if (!cls_belongs_to_core_lib) {
       if (interface.IsBoolType() ||
           interface.IsNumberType() ||
           interface.IsIntType() ||
           interface.IsDoubleType() ||
           interface.IsStringType() ||
-          (interface.IsFunctionType() && !cls.IsSignatureClass()) ||
           interface.IsDynamicType()) {
         const Script& script = Script::Handle(cls.script());
         ReportError(Error::Handle(),  // No previous error.
                     script, cls.token_pos(),
                     "'%s' is not allowed to extend or implement '%s'",
                     String::Handle(cls.Name()).ToCString(),
                     String::Handle(interface_class.Name()).ToCString());
       }
     }
     interface_class.set_is_implemented();
@@ skipping 225 matching lines @@
   expected_name ^= String::New("_offset");
   ASSERT(String::EqualsIgnoringPrivateKey(name, expected_name));
   field ^= fields_array.At(2);
   ASSERT(field.Offset() == TypedDataView::length_offset());
   name ^= field.name();
   ASSERT(name.Equals("length"));
 #endif
 }
 
 }  // namespace dart