ranges reading garbage

[John Colvin via Digitalmars-d-learn]

On Sunday, 15 February 2015 at 18:43:35 UTC, bearophile wrote:
> John Colvin:
>
>> prints things like [0, 4, 5, 1, 1, 1459971595, 1459971596, 2, 
>> 2, 1459971596, 1459971597, 3, 4, 8, 9, 5, 5, 4441427819, 
>> 4441427820, 6, 6, 4441427820, 4441427821, 7] but the output 
>> isn't consistent, the big numbers change on each run.
>
> Try to replace the only() with:
>
> [y, y+ys.length, y+ys.length+1, y+1]
>
> Like this:
>
>
> import std.range, std.algorithm, std.stdio;
>
> void foo(in float[] data, in float[] xs, in float[] ys) @safe {
>     iota(0, data.length, ys.length)
>     .map!(xBase => iota(xBase, xBase + ys.length - 1)
>                    .map!(y => [y, y+ys.length, y+ys.length+1, 
> y+1])
>                    .joiner)
>     .joiner
>     .writeln;
> }
>
> void main() {
>     foo([1,2,3,4,5,6,7,8], [0.1,0.2], [10,20,30,40]);
> }
>
>
>
> In Rust the compiler enforces that all stack-allocated data 
> doesn't come from dead stack frames. In D you have to be 
> careful to avoid doing it. In future this kind of bugs will be 
> hopefully avoided by a better tracking of the memory.
>
> I am not sure if http://wiki.dlang.org/DIP69 is able to avoid 
> this bug, if it can't, then DIP69 needs to be improved.
>
> Bye,
> bearophile

But std.range.OnlyResult!(size_t, 4) is a value type, I don't see 
where the stack reference is being leaked.