As its name implies, UndefTolerant only tolerates undef temporarily, whereas Maybe indicates undef is a valid value. 

$o->maybe(undef);     # Ok, valid value
$o->tolerant(undef);  # Dies, invalid value

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I presume this is intentional, so it's useless to me.

In reply to Re^2: Moose type question by ikegami
in thread Moose type question by Sue D. Nymme

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