weird exception on windows

[Szabo Bogdan]

On Friday, 15 December 2017 at 09:24:07 UTC, Kagamin wrote:
> Try printf debugging in case argument is invalid.

ah .. ok ...

I tried to debug the issue and it looks like the filename is 
valid and there is no null value.

I am thinking that the value is destroyed before it reach the 
`GetFileAttributesW` or during that call... but I don't see how 
that is possible.