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 1510 matching lines @@
     // Check for illegal self references.
     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(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());

[Florian Schneider, 2013/08/12 18:03:06]

Do we rely on this assertion somewhere else?

 
     // 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 329 matching lines @@
       case kArrayCid:
       case kImmutableArrayCid:
       case kGrowableObjectArrayCid:
 #define DO_NOT_EXTEND_TYPED_DATA_CLASSES(clazz)                                \
       case kTypedData##clazz##Cid:                                             \
       case kTypedData##clazz##ViewCid:                                         \
       case kExternalTypedData##clazz##Cid:
       CLASS_LIST_TYPED_DATA(DO_NOT_EXTEND_TYPED_DATA_CLASSES)
 #undef DO_NOT_EXTEND_TYPED_DATA_CLASSES
       case kByteDataViewCid:
-      case kDartFunctionCid:
       case kWeakPropertyCid:
         is_error = true;
         break;
+      case kDartFunctionCid:
+        // Signature classes, which are compiler generated and represent a

[Ivan Posva, 2013/08/13 07:35:09]

I don't think this is a valid restriction.

[Florian Schneider, 2013/08/13 14:52:20]

Done.

+        // function type, are allowed to extend the Function class.
+        if (!cls.IsSignatureClass()) 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()) {
           is_error = true;
         }
         break;
       }
     }
@@ skipping 22 matching lines @@
                   "'dynamic' may not be used as interface");
     }
     interface_class = interface.type_class();
     if (interface_class.IsSignatureClass()) {
       const Script& script = Script::Handle(cls.script());
       ReportError(script, cls.token_pos(),
                   "'%s' is used where an interface or class name is expected",
                   String::Handle(interface_class.Name()).ToCString());
     }
     // Verify that unless cls belongs to core lib, it cannot extend or implement
     // any of bool, num, int, double, String, Function, dynamic.

[Ivan Posva, 2013/08/13 07:35:09]

ditto for Function

[Florian Schneider, 2013/08/13 14:52:20]

Done.

     // 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.IsFunctionType() ||
           interface.IsDynamicType()) {
         const Script& script = Script::Handle(cls.script());
         ReportError(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();
     // Now resolve the super interfaces.
@@ skipping 217 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