Region allocator strage error

[Marc Schütz via Digitalmars-d-learn]

On Monday, 1 February 2016 at 12:05:53 UTC, ref2401 wrote:
> On Sunday, 31 January 2016 at 14:48:34 UTC, ref2401 wrote:
>> I am getting runtime error: 
>> core.exception.AssertError at std\experimental\allocator\building_blocks\region.d(235): Assertion failure
>
> At least tell me can anyone replicate it?

Missing imports for c&p:
import std.experimental.allocator;
import std.experimental.allocator.building_blocks;

I can't reproduce it on Linux x86_64, neither with latest DMD 
from git, nor DMD 2.070.0.

It's the following assert, maybe it helps finding the cause:
https://github.com/D-Programming-Language/phobos/blob/master/std/experimental/allocator/building_blocks/region.d#L235