F# option (FSharpOption<T>) fails to deserialize

[cata]

Adding an interface that uses FSharpOption<T> results in compile-time serializers being generated. This breaks the deserialization of the F# option type.

[cata]

@ReubenBond - It would be great if you could give this a look. Repro available in #1417

I have tried to fix the issue but failed - a System.Security.VerificationException get triggered at deserialization time, with the message Operation could destabilize the runtime. The stack trace is:

Test Name:  UnitTests.Serialization.SerializationTestsFsharpTypes.SerializationTests_FSharp_IntOption_Some
Test FullName:  UnitTests.Serialization.SerializationTestsFsharpTypes.SerializationTests_FSharp_IntOption_Some
Test Source:    C:\code\ca-ta\orleans\test\Tester\SerializationTests\SerializationTests.FSharpTypes.cs : line 28
Test Outcome:   Failed
Test Duration:  0:00:03.61

Result StackTrace:  
at valueSet(FSharpOption`1 , Int32 )
   at UnitTests.GrainInterfaces.OrleansCodeGenMicrosoft_FSharp_Core_FSharpOptionSerializer`1.Deserializer(Type expected, BinaryTokenStreamReader stream) in C:\code\ca-ta\orleans\src\TestGrainInterfaces\Properties\orleans.codegen.cs:line 7760
   at Orleans.Serialization.SerializationManager.DeserializeInner(Type expected, BinaryTokenStreamReader stream) in C:\code\ca-ta\orleans\src\Orleans\Serialization\SerializationManager.cs:line 1525
   at Orleans.Serialization.SerializationManager.DeserializeInner[T](BinaryTokenStreamReader stream) in C:\code\ca-ta\orleans\src\Orleans\Serialization\SerializationManager.cs:line 1435
   at Orleans.Serialization.SerializationManager.DeserializeFromByteArray[T](Byte[] data) in C:\code\ca-ta\orleans\src\Orleans\Serialization\SerializationManager.cs:line 1709
   at Orleans.Serialization.SerializationManager.RoundTripSerializationForTesting[T](T source) in C:\code\ca-ta\orleans\src\Orleans\Serialization\SerializationManager.cs:line 2203
   at UnitTests.Serialization.SerializationTestsFsharpTypes.RoundtripSerializationTest[T](T input) in C:\code\ca-ta\orleans\test\Tester\SerializationTests\SerializationTests.FSharpTypes.cs:line 22
   at UnitTests.Serialization.SerializationTestsFsharpTypes.SerializationTests_FSharp_IntOption_Some() in C:\code\ca-ta\orleans\test\Tester\SerializationTests\SerializationTests.FSharpTypes.cs:line 29
Result Message: System.Security.VerificationException : Operation could destabilize the runtime.

I've run peverify on the grain interfaces assembly (the one containing the generated serializers), but no errors were found. Also, I've debugged the tests and the types seem correct... and yet the tests fail.

I have also experimented with temporarily suppressing interface code gen (by commenting the Orleans targets in TestGraininterfaces.csproj) and manually commenting out the generated OrleansCodeGenMicrosoft_FSharp_Core_FSharpOptionSerializer<T>. While this change did allow the tests to pass, attempting the same approach in our system did not work (still getting the exception in valueSet) - so I am quite stumped.

Needless to say, this issue prevents us (and I suspect others using F#) from upgrading to any Orleans version newer than 1.0.9.
Any suggestions on how to attack this issue (as well as any workarounds/hacks that may come to mind) are very welcome.

[cata]

@ReubenBond - any feedback on this one? Note that #1424 and #1422 may be related?

[ReubenBond]

Fixed in #1504, specifically this commit. There was a security/trust issue which was remedied by emitting the field acessor DynamicMethods into the same module as the field's type instead of into the declaring type's module. I'm not completely certain that there will never be a case where the declaring type has a higher security requirement than the field - it seems plausible. In that case we will have to investigate other options such as raising the trust level of Orleans.dll. Hopefully this all goes away in .NET Core.

[cata]

@ReubenBond - thanks, and thanks for the commit pointer - I'll update #1417 shortly.

[ReubenBond]

Fixed by #1504