I accidently sent the bug in an incomplete form, here's the complete description:

With the specified configuration, code similar to the following

  IOP::ServiceContext_var context = ... // get a service context
  IOP::Codec_var codec = ... // get a codec

  Any_var ctxVal = codec->decode(context->context_data);


produces a compile-time error on MSVC similar to:

error C2664: 'decode' cannot convert parameter 1 from 'class IOP::ServiceContext::_tao_seq_Octet' to 'const class CORBA_OctetSeq &'

due to the fact that the PIDL argument type for the decode operation is mapped differently from IOP::ServiceContext context_data member:

local interface Codec {
  ...
  any decode(in CORBA::OctetSeq) ...
  ...
};

and

struct ServiceContext {
  ...
  sequence<octet> context_data;
};

The workaround is to construct a temporary CORBA::OctetSeq type from the ServiceContext member. e.g.

  CORBA::OctetSeq tmp(
                    context->context_data.length();
                    context->context_data.length();
                    context->context_data.get_buffer();
                    0);

and pass it as the argument.

I'm not totally sure this is a bug as such, but it would be handy to able to have the CORBA::OctetSeq be used interchangeably with the anonymous Octet sequence type (especially since the OctetSeq is just a typedef of the anonymous type).