>> Triskadekaphobiacs are presumably upset that, although 13.untrust appears to succeed and reinforce their beliefs, the state doesn't stick; 13.untrusted? subsequently returns false. Similarly, logicians and cynics alike must, respectively, rejoice and despair that `true.untrust.untrusted?` is perpetually false.
>
> Whoa! The current behavior of 1.9 is never reasonable.
> Here is a patch:

Thank you, Yusuke. :-) While I would prefer that immediates couldn't
be tainted/untrusted, I accept that's a topic for the future. For now,
that patch would certainly restore some sanity. :-)