Setting array length to 0 discards reserved allocation?

[safety0ff via Digitalmars-d]

On Thursday, 24 July 2014 at 23:30:13 UTC, Andrew Godfrey wrote:
> Is this a bug? Or am I misunderstanding
> something?
>

You need to use assumeSafeAppend before increasing the length 
again to avoid allocating new storage.

The runtime doesn't know that `a` is the only reference to that 
array, so increasing the length causes an allocation to avoid 
stomping on data.