Rehash canonical constants table for each class that can be affected by the 'become' operation

runtime/vm/verifier.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/verifier.h"
 
 #include "platform/assert.h"
 #include "vm/dart.h"
 #include "vm/dart_api_state.h"
 #include "vm/freelist.h"
@@ skipping 74 matching lines @@
 
 #if defined(DEBUG)
 VerifyCanonicalVisitor::VerifyCanonicalVisitor(Thread* thread)
     : thread_(thread), instanceHandle_(Instance::Handle(thread->zone())) {}
 
 
 void VerifyCanonicalVisitor::VisitObject(RawObject* obj) {
   if (obj->GetClassId() >= kInstanceCid) {
     if (obj->IsCanonical()) {
       instanceHandle_ ^= obj;
-      ASSERT(instanceHandle_.CheckIsCanonical(thread_));
+      const bool is_canonical = instanceHandle_.CheckIsCanonical(thread_);
+      if (!is_canonical) {
+        OS::PrintErr("Instance `%s` is not canonical!\n",
+                     instanceHandle_.ToCString());
+      }
+      ASSERT(is_canonical);
     }
   }
 }
 #endif  // defined(DEBUG)
 
 }  // namespace dart