Bug 41280 - System.MethodAccessException is thrown from wrong frame
Summary: System.MethodAccessException is thrown from wrong frame
Alias: None
Product: Runtime
Classification: Mono
Component: JIT ()
Version: unspecified
Hardware: PC Mac OS
: --- normal
Target Milestone: ---
Assignee: Bugzilla
Depends on:
Reported: 2016-05-24 09:51 UTC by Marek Safar
Modified: 2016-05-29 04:27 UTC (History)
3 users (show)

Is this bug a regression?: ---
Last known good build:

y.exe (4.00 KB, application/x-msdownload)
2016-05-24 09:51 UTC, Marek Safar
y-lib.dll (3.00 KB, application/x-msdownload)
2016-05-24 09:52 UTC, Marek Safar

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Description Marek Safar 2016-05-24 09:51:45 UTC
Created attachment 16083 [details]

Execute enclosed test

It fails with

Unhandled Exception:
System.MethodAccessException: Method `Ex:Private ()' is inaccessible from method `X/<Foo>c__async0:MoveNext ()'

  at System.Runtime.CompilerServices.AsyncTaskMethodBuilder.Start[TStateMachine] (TStateMachine& stateMachine) <0x9320e8 + 0x000d3> in <filename unknown>:0
  at X.Foo () <0x92f290 + 0x000bb> in <filename unknown>:0
  at M.Main () <0x92f188 + 0x00027> in <filename unknown>:0

which is wrong because 'System.MethodAccessException' does not happen within "::Start" method but inside "::MoveNext" method.

.NET handles this correctly and throws

System.AggregateException: One or more errors occurred. ---> System.MethodAccessException: Attempt by method 'X+<Foo>c__async0.MoveNext()' to access method 'Ex.Private()' failed.
   at X.<Foo>c__async0.MoveNext()
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
   at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
   at M.Main()

Why this matters is that Mono at the end throws different exception than .net
Comment 1 Marek Safar 2016-05-24 09:52:12 UTC
Created attachment 16084 [details]
Comment 2 Zoltan Varga 2016-05-29 04:27:46 UTC
Fixed in mono master.