**Upstream:** https://github.com/vmihailenco/msgpack/issues/339 Duplicate of #21 (upstream #304). Same root cause: `ptrValueDecoder` unaddressable value panic when decoding nil into non-addressable values.
Upstream: vmihailenco#339
Duplicate of #21 (upstream vmihailenco#304). Same root cause:
ptrValueDecoderunaddressable value panic when decoding nil into non-addressable values.