Associative array references

[Maxim Fomin]

On Monday, 2 December 2013 at 13:30:44 UTC, Atila Neves wrote:
> Bug or feature? This one caught me by surprise:
>
> void main() {
>     {
>         int[string] aa[string];
>         aa["foo"]["bar"] = 1;
>         assert(aa["foo"]["bar"] == 1); //ok
>
>         auto aa2 = aa;
>         aa2["boo"]["dar"] = 2;
>         assert(aa["foo"]["bar"] == 1); //ok
>     }
>
>     {
>         int[string] aa[string]; //not set to anything yet
>
>         auto aa2 = aa;
>         aa2["boo"]["dar"] = 2;
>         assert(aa["foo"]["bar"] == 1); //oops
>     }
> }
>
> It seems that assigning an AA to another makes both point at 
> the same data only if the first array has data to begin with. 
> Is that the expected behaviour?
>
> Atila

I would say it is consequence of current implementation, and, 
taking into account ongoing efforts to rewrite AA implementation, 
this special detail of null AA behavior may one day be gone.