Currently this is accepted:

int[2] m = cast(int[2])[1, 2];

But Kenji suggests that the cast from int[] to int[2][1] should not be accepted. Do you know why?

Reference:
https://issues.dlang.org/show_bug.cgi?id=7514

Bye and thank you,
bearophile

On Wednesday, 21 January 2015 at 14:31:15 UTC, bearophile wrote:
> Currently this is accepted:
>
> int[2] m = cast(int[2])[1, 2];
>
> But Kenji suggests that the cast from int[] to int[2][1] should not be accepted. Do you know why?
>
> Reference:
> https://issues.dlang.org/show_bug.cgi?id=7514
>
> Bye and thank you,
> bearophile

This is because of the .sizeof property, for example:

void main(string[] args)
{
    int[3] m = cast(int[3])[1, 2, 3];
    writeln(m.sizeof);
    writeln([1, 2, 3].sizeof);
}

outputs 12 / 8

Your previous example is corner case, it's 8/8 in both.

On Wednesday, 21 January 2015 at 14:41:48 UTC, Baz wrote:
> On Wednesday, 21 January 2015 at 14:31:15 UTC, bearophile wrote:
>> Currently this is accepted:
>>
>> int[2] m = cast(int[2])[1, 2];
>>
>> But Kenji suggests that the cast from int[] to int[2][1] should not be accepted. Do you know why?
>>
>> Reference:
>> https://issues.dlang.org/show_bug.cgi?id=7514
>>
>> Bye and thank you,
>> bearophile
>
> This is because of the .sizeof property, for example:
>
> void main(string[] args)
> {
>     int[3] m = cast(int[3])[1, 2, 3];
>     writeln(m.sizeof);
>     writeln([1, 2, 3].sizeof);
> }
>
> outputs 12 / 8
>
> Your previous example is corner case, it's 8/8 in both.

with -m32 of course.

Baz:

>     int[3] m = cast(int[3])[1, 2, 3];
>     writeln(m.sizeof);
>     writeln([1, 2, 3].sizeof);

The sizeof values aren't relevant for D array casts. What matters are the array "contents".

Bye,
bearophile

> The sizeof values aren't relevant for D array casts. What matters are the array "contents".

See:

void main() {
    int[5] m = cast(int[5])[1, 2, 3, 4, 5];
    assert(m == [1, 2, 3, 4, 5]);
    pragma(msg, m.sizeof); // 20u
    pragma(msg, [1, 2, 3, 4, 5].sizeof); // 8u
}


Bye,
bearophile

On Wednesday, 21 January 2015 at 18:08:44 UTC, bearophile wrote:
>> The sizeof values aren't relevant for D array casts. What matters are the array "contents".
>
> See:
>
> void main() {
>     int[5] m = cast(int[5])[1, 2, 3, 4, 5];
>     assert(m == [1, 2, 3, 4, 5]);
>     pragma(msg, m.sizeof); // 20u
>     pragma(msg, [1, 2, 3, 4, 5].sizeof); // 8u
> }
>
>
> Bye,
> bearophile

i'm sorry if I've lead you on a wrong way.
My bad.