How to diagnose problems related with compilation errors on il2cpp 64b

recently I had to update unity to 5.0.1 and switch complator to il2cpp 64b on iOS. I have a huge amount of compilation errors like:

Bulk_Assembly-CSharp_10.cpp:57:61: Unknown type name 'U3CLoadCompletionStateU3Ec__AnonStorey75_t1534';
Bulk_Assembly-CSharp_10.cpp:71:19: Use of undeclared identifier 'TutorialStepXML_get_StepId_m8241';
Bulk_Assembly-CSharp_10.cpp:459:3: Unknown type name 'BaseTutorialStep_t1515';
...
and many, many more

How to diagnose problem and how to find the reason of that errors? Those messages tells me nothing, so I can’t even try fix a problem.

Ideally, you should not have to diagnose these errors. Anytime there is a compilation error in C++ code generated by IL2CPP, that indicates a bug in IL2CPP. So first of all, please submit a bug report with this project, so that we can correct it.

Until we can correct the problem, you might be able to work around it by determining which managed code is causing the problem. In this case, it looks like the managed types LoadCompletionState and BaseTutorialStep are problematic. Usually it is difficult to determine how the C++ compile errors are caused by the managed code. If it is possible to get at least part of the project working without these types, then the best option might be to temporarily remove them and continue.

Unfortunately, this is the best answer I can provide now. In reality, we need to correct the bug causing this problem.