Problem Benchmarking HashSet from containers-em

[Nordlöw via Digitalmars-d-learn]

On Thursday, 22 October 2015 at 17:32:34 UTC, Justin Whear wrote:
> On Thu, 22 Oct 2015 11:55:37 +0000, Nordlöw wrote:
>
>> What's wrong?
>
> HashSet has a disabled default constructor; you need to supply 
> the allocator instance to the constructor here 
> https://github.com/nordlow/ 
> justd/blob/master/containers_ex.d#L17

Doesn't work.

If I change

     auto set = HashSet!(E, Allocator)();

to

     auto set = HashSet!(E, Allocator)(Allocator());

it errors as

containers_ex.d(17,38): Error: constructor 
containers.hashset.HashSet!(const(int), Mallocator, generateHash, 
false).HashSet.this (ulong bucketCount) is not callable using 
argument types (Mallocator)
containers_ex.d(30,16): Error: template instance 
containers_ex.hashSet!(Mallocator, const(int)[]) error 
instantiating
containers_ex.d(35,5): Error: static assert  (is(typeof(__error) 
== const(int)*)) is false

My existing call to

     auto set = HashSet!(E, Allocator)();

works for Mallocator as in

https://github.com/nordlow/justd/blob/master/containers_ex.d#L17

but not for

     InSituRegion!(1024*1024, T.alignof)

Why? Please, help.