ranges reading garbage

[anonymous via Digitalmars-d-learn]

On Sunday, 15 February 2015 at 18:13:44 UTC, John Colvin wrote:
> Simplified from something bigger:
>
> import std.range, std.algorithm, std.stdio;
>
> void foo(float[] data, float[] xs, float[] ys)
> {
>     auto indices = iota(0, data.length, ys.length)
>         .map!(xBase =>
>                 iota(xBase, xBase + ys.length - 1)
>                 .map!(y =>
>                     only(y, y+ys.length, y+ys.length+1, y+1))
>                 .joiner())
>         .joiner();
>     writeln(indices);
> }
>
> void main()
> {
>     foo([1,2,3,4,5,6,7,8],
>             [0.1,0.2], [10,20,30,40]);
> }
>
> 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.

Reduced some more:

import std.algorithm, std.stdio;
void main()
{
     int ys_length = 4;
     auto indices = [0]
         .map!(xBase => [0].map!(y => ys_length))
         .joiner();
     writeln(indices);
}