ranges reading garbage

[John Colvin via Digitalmars-d-learn]

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.