associative array with Parallel

[frame]

On Thursday, 22 July 2021 at 05:53:01 UTC, jfondren wrote:
> On Thursday, 22 July 2021 at 05:46:25 UTC, seany wrote:
>> But what about this :
>>
>>     int [ string ] ii;
>>     ii.length = somearray.length;
>>     foreach(i,dummy; parallel(somearray)) {
>>       string j = generateUniqueString(i);
>>       ii[j] ~= somefunc(dummy);
>>     }
>>
>>
>> Is this also guaranteed thread safe?
>
> No. Consider 
> https://programming.guide/hash-tables-open-vs-closed-addressing.html
>
> In the open-addressing case, one thread may be searching the 
> backing array while another thread is modifying it. In the 
> closed-addressing case, one thread may be modifying a linked 
> list while another thread is searching it.

This is another parallel foreach body conversion question.
Isn't the compiler clever enough to put a synchronized block here?