nftables segv while trying to use nat redirection with map

[Steve Horsley <steve.horsley@gmail.com>]

I would like to do host redirection using nftables, and using maps for 
efficient host address lookup (thousands of entries).
As a first step, I tried just natting the output from my laptop but the 
real use will be on the prerouting chain:
172.16.0.1 -> 8.8.8.8.
The following works as intended:
     nft add table nat
     nft add chain nat output { type nat hook output priority 0 \; }
     nft add rule nat output ip daddr 172.16.1.1 dnat 8.8.8.8
     ping 172.16.1.1

But I can't get it to work using maps - this causes a segmentation error:
     nft flush ruleset
     nft add table nat
     nft add chain nat output { type nat hook output priority 0 \; }
     nft add rule ip nat output dnat ip daddr map { 172.16.1.1 : 8.8.8.8 }
     nft list ruleset

I don't know if I just have the wrong syntax, if it's a bug in nft, or 
if it's just something I shouldn't be trying to do in the first place. I 
am using nftables 0.4 (ubuntu 15.10 beta) but had the same result on 
ubuntu 15.04.