On Saturday, 26 September 2015 at 15:56:54 UTC, Jay Norwood wrote:
> This results in a compile error:
> auto sum3 = taskPool.reduce!"a + b"(iota(1UL,1000001UL));
>
> I believe there was discussion of this problem recently ...

https://issues.dlang.org/show_bug.cgi?id=14832

https://issues.dlang.org/show_bug.cgi?id=6446

looks like the problem has been reported a couple of times.  I probably saw the discussion of the 8/22 bug.