Bug with decoding a sequence of optionals with unique tags

[w00drow]

Test:

#include "ut.hpp"
#include "ut_proto.hpp"

struct o_params : med::sequence<
        O<C<0x01>, FLD_UC>,
        O<C<0x02>, FLD_U8>,
        O<C<0x03>, FLD_U16>>
{
};

struct m_params : med::sequence<
        M<FLD_UC>,
        M<FLD_U8>,
        M<FLD_U16>>
{
};

struct params : med::sequence<
        M<FLD_U8>,
        O<C<0x04>, o_params>,
        O<C<0x05>, m_params>>
{

};


TEST(sequence, optional)
{
    params p1;

    p1.ref<FLD_U8>().set(0);

    p1.ref<o_params>().ref<FLD_U8>().set(1);

    p1.ref<m_params>().ref<FLD_UC>().set(2);
    p1.ref<m_params>().ref<FLD_U8>().set(3);
    p1.ref<m_params>().ref<FLD_U16>().set(4);

    uint8_t e_buffer[64];
    med::encoder_context e_ctx{e_buffer};
    encode(med::octet_encoder{e_ctx}, p1);

    uint8_t d_buffer[64];
    med::allocator d_alloc{d_buffer};
    med::decoder_context<med::allocator> d_ctx{e_ctx.buffer().get_start(), e_ctx.buffer().get_offset(), &d_alloc};
    params p2;
    med::decode(med::octet_decoder{d_ctx}, p2);

    EXPECT_NE(p2.get<m_params>(), nullptr);
}

Adding length to o_params fixes the problem (O<C<0x04>, L, o_params>) .