Partial arrays reclaimed?

[Ivan Kazmenko via Digitalmars-d-learn]

On Friday, 27 January 2017 at 23:22:17 UTC, Nick Sabalausky wrote:
> Suppose an array is being used like a FIFO:
>
> -----------------------
> T[] slice;
>
> // Add:
> slice ~= T();
>
> // Remove:
> slice = slice[1..$];
> -----------------------
>
> Assuming of course there's no other references to the memory, 
> as this gets used, does the any of the memory from the removed 
> elements ever get GC'd?

As I see it, the line
slice = slice[1..$];
effectively ends slice's in-place appending capabilities.  So 
each append after remove will likely reallocate.  You have to use 
assumeSafeAppend to re-enable appending in place.

Here [1] is an old thread about the caveats of using built-in 
arrays as queues and stacks.  If not in a hurry, the better 
option is perhaps to just write the respective wrapper structs 
which explicitly store indices, instead of using built-in slices 
and assumeSafeAppend all over the place.

Ivan Kazmenko.

[1] 
http://forum.dlang.org/post/yrxspdrpusrrijmfyldc@forum.dlang.org