Daniel Murphy:

> It's a bug, the compiler shouldn't be inserting a cast when the value implicitly converts.  It's also a bug when the compiler tries to optimise away the variable to a literal when passing by reference, I've got a patch for this I haven't written up yet.

http://d.puremagic.com/issues/show_bug.cgi?id=6708

Thank you for all the answers.

Bye,
bearophile