[perl #129363] duckmap doesn't retain structure types

[Zoffix Znet via RT]

On Tue, 08 Nov 2016 06:31:15 -0800, c...@fastmail.co.uk wrote:
> Pull requests raised for discussion:
> 
> https://github.com/rakudo/rakudo/pull/915
> https://github.com/perl6/roast/pull/180

Merged. Thanks.