Quick step 1: dump stack in AbstractType::IsInstantiated

runtime/vm/object.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/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 15498 matching lines @@
 TokenPosition AbstractType::token_pos() const {
   // AbstractType is an abstract class.
   UNREACHABLE();
   return TokenPosition::kNoSource;
 }
 
 
 bool AbstractType::IsInstantiated(TrailPtr trail) const {
   // AbstractType is an abstract class.
   // TODO(srdjan) : Remove temporary code.
+  Profiler::DumpStackTrace(true);
+  Profiler::DumpStackTrace(false);

[Cutch, 2016/04/25 23:16:11]

DBC: Call it with false first and then with true. The true case might crash
while walking the stack.

[srdjan, 2016/04/25 23:29:16]

Done.

   if (Compiler::IsBackgroundCompilation()) {
     UNREACHABLE();
   }
   UNREACHABLE();
   return false;
 }
 
 
 bool AbstractType::IsFinalized() const {
   // AbstractType is an abstract class.
@@ skipping 6757 matching lines @@
   return UserTag::null();
 }
 
 
 const char* UserTag::ToCString() const {
   const String& tag_label = String::Handle(label());
   return tag_label.ToCString();
 }
 
 }  // namespace dart