Can we just have struct inheritence already?

[Timon Gehr]

On 14.06.19 03:17, Exil wrote:
> On Friday, 14 June 2019 at 01:12:21 UTC, Timon Gehr wrote:
>> On 14.06.19 02:23, Exil wrote:
>>> On Thursday, 13 June 2019 at 21:26:37 UTC, Tim wrote:
>>>> On Thursday, 13 June 2019 at 20:55:34 UTC, Exil wrote:
>>>>> This problem happens because you are used @trusted. If you used 
>>>>> @safe you wouldn't be able to increment pointers and modify the 
>>>>> values the way you did in @trusted.
>>>>
>>>> Here is a completly @safe version:
>>>>
>>>> import std.stdio;
>>>>
>>>> static int[2] data;
>>>> static int[253] data2;
>>>>
>>>> void test(bool b) @safe
>>>> {
>>>>     data[b]++;
>>>> }
>>>>
>>>> void main() @safe
>>>> {
>>>>     bool b = void;
>>>>     writeln(data, data2);
>>>>     test(b);
>>>>     writeln(data, data2);
>>>> }
>>>>
>>>> If b is valid only data can change. But for me data2 changes, even 
>>>> though it is never written to.
>>>
>>> This is a bug.
>>
>> Yes. And the bug is either
>> - that `void` initialization of `bool` is `@safe`.
>> - that `void` initialization of `bool` can produce a value that is 
>> both `true` and `false`.
>> - that boolean values are assumed to be either `true` or `false` in 
>> @safe code.
>>
>> Which one seems most plausible to you?
> 
> None of them. Code generation is incorrect for boolean values.
> ...

That's the second option above... And I already explained why that 
answer is not satisfactory.

>>> It seems it doesn't do bounds checking for the index because it is a 
>>> bool value and it is less than the static type. If you change the 
>>> array to a dynamically allocated one, an assert is hit as expected.
>>
>> That's not expected, this is just the compiler not being as smart as 
>> it could be given the available information.
> 
> A value is used that is out of bounds of the array, yes that assert is 
> expected.

The compiler is able to derive that it is not out of bounds...