Relax assert when applying a mixin application alias (fixes #25617).

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 1945 matching lines @@
   // class rather than to those of the mixin application alias class.
   // This type parameter substitution is performed by an instantiation step.
   // It is important that the type parameters of the mixin application class
   // are not finalized yet, because new type parameters may have been added
   // to the super class.
   const Class& super_class = Class::Handle(zone, super_type.type_class());
   ASSERT(mixin_app_class.SuperClass() == super_class.raw());  // Will change.
   const intptr_t num_super_type_params = super_class.NumTypeParameters();
   AbstractType& type = AbstractType::Handle(zone);
   // The instantiator is mapping finalized type parameters of mixin_class to
-  // unfinalized type parameters of mixin_app_class.
-  ASSERT(aliased_mixin_type.IsFinalized());
+  // unfinalized type parameters of mixin_app_class. Therefore, the type
+  // arguments of mixin_class_super_type must be finalized, since they get
+  // instantiated by this instantiator. Finalizing the types in mixin_class
+  // will finalize mixin_class_super_type.
+  // The aliased_mixin_type does not need to be finalized, but only resolved.
+  ASSERT(aliased_mixin_type.IsResolved());
   const Class& aliased_mixin_type_class = Class::Handle(zone,
       aliased_mixin_type.type_class());
+  FinalizeTypesInClass(mixin_class);
   const intptr_t num_aliased_mixin_type_params =
       aliased_mixin_type_class.NumTypeParameters();
   ASSERT(inserted_class.NumTypeParameters() ==
          (num_super_type_params + num_aliased_mixin_type_params));
   const AbstractType& mixin_class_super_type =
       AbstractType::Handle(zone, mixin_class.super_type());
   ASSERT(mixin_class_super_type.IsFinalized());
   // The aliased_mixin_type may be raw.
   const TypeArguments& mixin_class_super_type_args =
       TypeArguments::Handle(zone, mixin_class_super_type.arguments());
@@ skipping 1303 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