[mono-cecil] Modifying a type to implement an interface causes a type load error in PEVerify

[Philip_L]

I can't figure out why, but every time I try to modify an existing
type in the assembly with the following code:

...
            _hostField = new FieldDefinition("__host", _aopHostType,
FieldAttributes.Private);
            typeDef.Fields.Add(_hostField);

            // Implement IModifiedType
            if (typeDef.Interfaces.Contains(_modifiedInterfaceType))
                return;

            typeDef.Interfaces.Add(_modifiedInterfaceType);

            MethodAttributes attributes = MethodAttributes.Public |
MethodAttributes.HideBySig |
                                          MethodAttributes.SpecialName
| MethodAttributes.NewSlot |
                                          MethodAttributes.Virtual;

            // Implement the getter property
            _getHost = new MethodDefinition("get_Host", attributes,
_aopHostType);
            _getHost.ImplAttributes = MethodImplAttributes.Managed |
MethodImplAttributes.IL;
            CilWorker IL = _getHost.Body.CilWorker;
            IL.Emit(OpCodes.Ldarg_0);
            IL.Emit(OpCodes.Ldfld, _hostField);
            IL.Emit(OpCodes.Ret);

            // Implement the setter
            _setHost = new MethodDefinition("set_Host", attributes,
_voidType);
            _setHost.ImplAttributes = MethodImplAttributes.Managed |
MethodImplAttributes.IL;
            _setHost.Parameters.Add(new
ParameterDefinition(_aopHostType));

            IL = _setHost.Body.CilWorker;
            IL.Emit(OpCodes.Ldarg_0);
            IL.Emit(OpCodes.Ldarg_1);
            IL.Emit(OpCodes.Stfld, _hostField);
            IL.Emit(OpCodes.Ret);

            PropertyDefinition hostProperty =
                new PropertyDefinition("Host", _aopHostType,
PropertyAttributes.Unused);

            _getHost.IsPublic = true;
            _setHost.IsPublic = true;

            hostProperty.GetMethod = _getHost;
            hostProperty.SetMethod = _setHost;

            typeDef.Methods.Add(_getHost);
            typeDef.Methods.Add(_setHost);
            typeDef.Properties.Add(hostProperty);
...

After saving the modified assembly, I keep getting this error from
PEVerify:
---------------------------------------Error
Message---------------------------------------
Microsoft (R) .NET Framework PE Verifier.  Version  2.0.50727.42
Copyright (c) Microsoft Corporation.  All rights reserved.

[token  0x02000002] Type load failed.
1 Error Verifying testlibrary.dll
---------------------------------------Error
Message---------------------------------------

Is this a bug, or am I doing something wrong here? I thought this was
the most straightforward way to add an interface implementation to an
existing class, and I'm not sure whether this is a bug or not. Anyone
have any ideas?

Thanks in advance.

Regards,

Philip


--~--~---------~--~----~------------~-------~--~----~
--
mono-cecil
-~----------~----~----~----~------~----~------~--~---