Disallow extending a malformed type (issue 13940).

runtime/vm/object.cc

 // 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.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 1770 matching lines @@
   if (super_type() == AbstractType::null()) {
     return Class::null();
   }
   const AbstractType& sup_type = AbstractType::Handle(super_type());
   return sup_type.type_class();
 }
 
 
 void Class::set_super_type(const AbstractType& value) const {
   ASSERT(value.IsNull() ||
-         value.IsType() ||
+         (value.IsType() && !value.IsDynamicType()) ||
          value.IsBoundedType() ||
          value.IsMixinAppType());
   StorePointer(&raw_ptr()->super_type_, value.raw());
 }
 
 
 // Return a TypeParameter if the type_name is a type parameter of this class.
 // Return null otherwise.
 RawTypeParameter* Class::LookupTypeParameter(const String& type_name) const {
   ASSERT(!type_name.IsNull());
@@ skipping 13545 matching lines @@
   return "_MirrorReference";
 }
 
 
 void MirrorReference::PrintToJSONStream(JSONStream* stream, bool ref) const {
   JSONObject jsobj(stream);
 }
 
 
 }  // namespace dart