Type problem with 1.4.0

[Hlaaftana]

The problem here is that the `second` accessor accepts a `var DateTime` which 
is not automatically convertible from a `ref DateTime`. However, if you put 
`{.experimental: "implicitDeref".}` at the top of your module or use the 
dereference operator like `tie[].second = ti.second`, then it will work.