immutable(ubyte)[] to receive

[bauss]

On Thursday, 20 January 2022 at 10:19:37 UTC, bauss wrote:
> On Thursday, 20 January 2022 at 10:18:03 UTC, bauss wrote:
>> On Thursday, 20 January 2022 at 09:38:55 UTC, Alexey wrote:
>>>
>>>     Buffer[] t ;
>>>     t ~= cast(Buffer)"sdfsdfsdf";
>>>     t ~= cast(Buffer)"sdfsdfsdf";
>>>     immutable(Buffer[]) ti = cast(immutable)t;
>>>
>>
>> This is undefined behavior.
>>
>> Since ti isn't really immutable.
>>
>> You can still modify the original buffer (t).
>>
>> You should use const instead of immutable and, that goes for 
>> your functions too.
>>
>> They should receive const and not immutable.
>>
>> Summary:
>>
>> Mutable means: Anyone and anything can modify it.
>> Immutable means: Nobody will modify it, not here and not 
>> anywhere else. Initialization is only allowed, but not 
>> pointing to anything that has mutable references.
>> Const means: I promise not to modify it, but another mutable 
>> reference might.
>>
>> In your example t is a mutable reference, where as ti is an 
>> immutable reference.
>>
>> That's illegal and constitutes as UB (Undefined behavior)
>>
>> It would have been legal if you either used const or if you 
>> made an immutable duplication of t with ex. t.idup.
>
> Oh wait, I just noticed Buffer is an alias to an immutable 
> array.
>
> Ignore what I just said...

I'm too fast again, well don't ignore entirely what I said, since 
you still modify an immutable reference by appending to t, I 
believe.

I'm not 100% sure about this one, but I'm 99% sure.