How to provide this arg or functor for algorithm?

[thedeemon via Digitalmars-d-learn]

On Monday, 17 August 2015 at 16:18:50 UTC, thedeemon wrote:
> I've just checked with my runtime GC hook. Here the call to 
> func() allocates 12 bytes via gc_malloc, and it's the same for 
> a 4-elements array, so it's not for the array itself, it's for 
> a closure, I think.

Also, compiling with -vgc says nothing, compiler (2.068) seems to 
miss this allocation.