When the utility is used by the ConsumeOperatorCopyableValuesChecker,
the checker guarantees that the lifetime can end at the consumes, that
there are no uses after those consumes. In that circumstance, the
utility maintains liveness to those consumes and as far as possible
without introducing a copy everywhere else.
The lack of complete lifetimes has forced the utility to extend liveness
of values to dead-ends. That extension, however, is in tension with the
use that the checker is putting the utility to. If there is a dead-end
after a consume, liveness must not be maintained to that dead-end.
rdar://147586673
The checker already verifies that no non-destroy consuming users occur
after any `move_value`s corresponding to `consume` operators applied to
a value. There may, however, be _destroy_ users after it.
Previously, the checker did not shorten the lifetime from those destroys
up to `move_value`s that appear after those `move_value`s. The result
was that the value's lifetime didn't end at the `consume`.
Here, the checker is fixed to rewrite the lifetimes so that they both
end at `consume`s and also maintain their lexical lifetimes on paths
away from the `consume`s. This is done by using
`OwnedValueCanonicalization`/`CanonicalizeOSSALifetime`.
Specifically, it passes the `move_value`s that correspond to
source-level `consume`s as the `lexicalLifetimeEnds` to the
canonicalizer. Typically, the canonicalizer retracts the lexical
lifetime of the value from its destroys. When these `move_value`s are
specified, however, instead it retracts them from the lifetime boundary
obtained by maximizing the lifetime within its original lifetime while
maintaining the property that the lifetime ends at those `move_value`s.
rdar://113142446
