why does this error out?

[lobo via Digitalmars-d-learn]

On Tuesday, 10 November 2015 at 04:34:22 UTC, Cauterite wrote:
> Here's the output I get (DMD v2.068.2):
>
> [1, 3, 10, 12, 21, 30, 100, 102, 111, 120, 201, 210]
> core.exception.AssertError at std\range\package.d(4603): Assertion 
> failure

iota.front() is complaining the range is empty from this line.

     harshads.filter!(h => h > 1000).front.writeln;

your hardas has no values > 1000 so the filter is empty. hardwas 
was seeded with iota(1,256), so the maximum value will be 252.

bye,
lobo