From this unittest in the documentation: http://www.digitalmars.com/d/2.0/phobos/std_range.html#iota

import std.algorithm;
import std.range;

void main() 
{
    auto rf = iota(0.0, 0.5, 0.1);
    assert(equal(rf, [0.0, 0.1, 0.2, 0.3, 0.4]));
}

This assertion fails. I'm not sure if it is because of floating-point representation being different(?) or if this is really a bug. But its in the docs, so the code either has to go or there's a bug.