Canonicalize mixin type during class finalization. Add asserts that most types are canonical.

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 2218 matching lines @@
     // In case of a bound error in the super type in production mode, the
     // finalized super type will have a BoundedType as type argument for the
     // out of bound type argument.
     // It should not be a problem if the class is written to a snapshot and
     // later executed in checked mode. Note that the finalized type argument
     // vector of any type of the base class will contain a BoundedType for the
     // out of bound type argument.
     super_type = FinalizeType(cls, super_type, kCanonicalizeWellFormed);
     cls.set_super_type(super_type);
   }
+  // Finalize mixin type.
+  Type& mixin_type = Type::Handle(cls.mixin());
+  if (!mixin_type.IsNull()) {
+    mixin_type ^= FinalizeType(cls, mixin_type, kCanonicalizeWellFormed);
+    cls.set_mixin(mixin_type);
+  }
   if (cls.IsSignatureClass()) {
     // Check for illegal self references.
     GrowableArray<intptr_t> visited_aliases;
     if (!IsAliasCycleFree(cls, &visited_aliases)) {
       const String& name = String::Handle(cls.Name());
       ReportError(cls, cls.token_pos(),
                   "typedef '%s' illegally refers to itself",
                   name.ToCString());
     }
     cls.set_is_type_finalized();
@@ skipping 933 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