immutable T.init, and pointers to mutable data

[monarch_dodra via Digitalmars-d-learn]

On Thursday, 25 September 2014 at 12:46:01 UTC, Steven 
Schveighoffer wrote:
> On 9/25/14 5:47 AM, monarch_dodra wrote:
>> I was playing around with how T.init works. And I think I may 
>> have found
>> a type loophole.
>>
>> Given that you may initialize a pointer member to the address 
>> to a
>> static global:
>>
>> //----
>> __gshared int a = 0;
>> struct S
>> {
>>     int* p = &a;
>> }
>> //----
>>
>> Then, in theory, any variable, be they mutable or const, are 
>> initialized
>> to T.init:
>>
>> //----
>> void main()
>> {
>>     immutable S s;
>> }
>> //----
>>
>> This is an issue, because I now have an immutable pointer that 
>> points to
>> mutable data:
>> //----
>>     immutable S s = S.init;
>>     immutable int* p = s.p;
>>     assert(*p == 0); //OK
>>     a = 5;
>>     assert(*p == 5); //OK
>> //----
>>
>> So this violates the type system...
>>
>> The question here is:
>> Is this "legit" code? At what point do you think my code 
>> should have
>> been rejected?
>
> It should be rejected. The declaration of s (the variable) 
> should be the trigger, since it casts the pointer to immutable.
>
> Please file a bug report.
>
> -Steve

Hum... So that means certain types just *can't* be initialized 
(as immutable) at all?