CTFE difference between dmd and ldc2

[Joseph Rushton Wakeling via Digitalmars-d-learn]

On Saturday, 7 January 2017 at 22:55:55 UTC, Joseph Rushton 
Wakeling wrote:
> I should probably also create a formal issue for this.  Any 
> thoughts on how best to break it down into a minimal example?  
> It does not appear easy to do so at first glance :-\

Turned out to be easier than I anticipated.  It was not a CTFE 
problem but one of default initialization of struct fields:
https://issues.dlang.org/show_bug.cgi?id=17073

In short, `void` default initialization seems to take priority 
with dmd regardless of anything else.