Why is my @pure function @system when placed in a struct?

[Dukc]

On Wednesday, 27 February 2019 at 17:23:21 UTC, Q. Schroll wrote:
> For whatever reason, when I put the code in a struct, the @safe 
> testing line tells me, it's @system now.

I tested a bit, and it appears that attribute inference is not 
done at all for templates inside structs -the attribute need not 
be a delegate:

struct S
     {
         static int fImpl(Ret)() { return Ret.init; }

         pragma(msg, __traits(getFunctionAttributes, fImpl!int)); 
// still tells us: `f` is @system
     }

void main(){}

A bug, unless I'm overlooking something.