Allocator troubles

[Luís Marques via Digitalmars-d]

I'm not having success trying to use the allocator API.

What am doing wrong here? (OS X, 64-bit)

     void main()
     {
         import std.exception;
         import std.experimental.allocator;
         import std.experimental.allocator.building_blocks.region;
         import std.stdio;

         static InSituRegion!1024 ralloc;
         IAllocator alloc = allocatorObject(&ralloc);

         enforce(alloc.make!int !is null);
         enforce(alloc.deallocateAll());

         enforce(alloc.make!int !is null);
         writeln("OK 1");

         enforce(alloc.deallocateAll());
         writeln("OK 2");
     }

     $ rdmd -g test.d
     OK 1
     Segmentation fault: 11


BTW, there doesn't seem to be any primitive like tryMake or an 
allocator building block that throws instead of returning null. I 
wanted to just replace my "new X" statements with a region 
allocator and leave the rest unchanged, so I had to create my own 
tryMake which wraps make calls with an enforcement of !is null. I 
was surprised by this omission (or did I miss something?). BTW, 
notice that I don't ever expect my allocator to return null 
unless there is a bug in my program, since the amount of memory 
needed is statically computed and carefully used, so it makes a 
lot of sense for me to just throw OutOfMemoryException.