Add compiler error when instantiating abstract class

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/bigint_operations.h"
@@ skipping 1819 matching lines @@
   ASSERT(token_pos >= 0);
   raw_ptr()->token_pos_ = token_pos;
 }
 
 
 void Class::set_is_interface() const {
   uword bits = raw_ptr()->state_bits_;
   raw_ptr()->state_bits_ = InterfaceBit::update(true, bits);
 }
 
+void Class::set_is_abstract() const {
+  uword bits = raw_ptr()->state_bits_;
+  raw_ptr()->state_bits_ = AbstractBit::update(true, bits);
+}
+
 
 void Class::set_is_const() const {
   uword bits = raw_ptr()->state_bits_;
   raw_ptr()->state_bits_ = ConstBit::update(true, bits);
 }
 
 
 void Class::set_is_finalized() const {
   ASSERT(!is_finalized());
   uword bits = raw_ptr()->state_bits_;
@@ skipping 9330 matching lines @@
   }
   return result.raw();
 }
 
 
 const char* WeakProperty::ToCString() const {
   return "_WeakProperty";
 }
 
 }  // namespace dart