Allow super type to be malformed (fixes issue 25426).

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/code_generator.h"
 #include "vm/flags.h"
 #include "vm/heap.h"
 #include "vm/isolate.h"
@@ skipping 2641 matching lines @@
   const Library& library = Library::Handle(zone, cls.library());
   ASSERT(!library.IsNull());
   const Script& script = Script::Handle(zone, cls.script());
   ASSERT(!script.IsNull());
   const GrowableObjectArray& type_args =
       GrowableObjectArray::Handle(zone, GrowableObjectArray::New());
   AbstractType& mixin_super_type =
       AbstractType::Handle(zone, mixin_app_type.super_type());
   ResolveType(cls, mixin_super_type);
   ASSERT(mixin_super_type.HasResolvedTypeClass());  // Even if malformed.
+  if (mixin_super_type.IsMalformedOrMalbounded()) {
+    ReportError(Error::Handle(zone, mixin_super_type.error()));
+  }
+  if (mixin_super_type.IsDynamicType()) {
+    ReportError(cls, cls.token_pos(),
+                "class '%s' may not extend 'dynamic'",
+                String::Handle(zone, cls.Name()).ToCString());
+  }
   // The super type may have a BoundedType as type argument, but cannot be
   // a BoundedType itself.
   CollectTypeArguments(cls, Type::Cast(mixin_super_type), type_args);
   AbstractType& mixin_type = AbstractType::Handle(zone);
   Class& mixin_type_class = Class::Handle(zone);
   Class& mixin_app_class = Class::Handle(zone);
   String& mixin_app_class_name = String::Handle(zone);
   String& mixin_type_class_name = String::Handle(zone);
   AbstractType& super_type_arg = AbstractType::Handle(zone);
   AbstractType& mixin_type_arg = AbstractType::Handle(zone);
@@ skipping 551 matching lines @@
   ASSERT(fields_array.Length() == ByteBuffer::NumberOfFields());
   field ^= fields_array.At(0);
   ASSERT(field.Offset() == ByteBuffer::data_offset());
   name ^= field.name();
   expected_name ^= String::New("_data");
   ASSERT(String::EqualsIgnoringPrivateKey(name, expected_name));
 #endif
 }
 
 }  // namespace dart