Properly handle unfinalized type parameters of generic mixins (fixes #26230).

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 975 matching lines @@
         type_arg = BoundedType::New(type_arg, instantiated_bound, type_param);
         arguments.SetTypeAt(offset + i, type_arg);
         continue;
       }
       // Shortcut the special case where we check a type parameter against its
       // declared upper bound.
       if (error.IsNull() &&
           !(type_arg.Equals(type_param) &&
             instantiated_bound.Equals(declared_bound))) {
         // If type_arg is a type parameter, its declared bound may not be
-        // resolved yet.
+        // finalized yet.
         if (type_arg.IsTypeParameter()) {
           const Class& type_arg_cls = Class::Handle(
               TypeParameter::Cast(type_arg).parameterized_class());
           AbstractType& bound = AbstractType::Handle(
               TypeParameter::Cast(type_arg).bound());
-          ResolveType(type_arg_cls, bound);
+          if (!bound.IsFinalized() && !bound.IsBeingFinalized()) {
+            bound = FinalizeType(type_arg_cls, bound, kCanonicalize);
+            TypeParameter::Cast(type_arg).set_bound(bound);
+          }
         }
         // This may be called only if type needs to be finalized, therefore
         // seems OK to allocate finalized types in old space.
         if (!type_param.CheckBound(type_arg, instantiated_bound,
                                    &error, NULL, Heap::kOld) &&
             error.IsNull()) {
           // The bound cannot be checked at compile time; postpone to run time.
           type_arg = BoundedType::New(type_arg, instantiated_bound, type_param);
           arguments.SetTypeAt(offset + i, type_arg);
         }
@@ skipping 2302 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