http://erdani.com/d/phobos-prerelease/std_experimental_allocator_porcelain.htmlAndrei
Now that https://issues.dlang.org/show_bug.cgi?id=8269 was fixed, how about that idea of using with(scopeAllocator(...)) { /* use theAllocator */ } ?
I.e. encapsulating auto oldAllocator = theAllocator; scope(exit) theAllocator = oldAllocator; theAllocator = allocatorObject(...); into a nice RAII type and then using it with WithStatement.