Borrow-Checker Interface

The PCG Analysis requires an implementation of the borrow-checker interface providing the following:

• A predicate $live(n,l)$, which holds iff the borrow extents in PCG node $n$ are all in scope at MIR location $l$
• A predicate $directly\_blocked(p,l)$, which holds iff place $p$ is directly blocked at MIR location $l$
• A predicate $blocks(p,p^{\prime },l)$ which holds iff mutating $p^{\prime }$ at $l$ would cause $p$ to be dead
• A predicate $outlives(r,r^{\prime },l)$ which holds iff $r$ must outlive $r^{\prime }$ at $l$
• A function $borrows\_blocking(p,l)$ which returns the set of borrows that would be invalidated if $p$ was modified at $l$
• A function $twophase\_borrow\_activations(l)$ which returns the set of two-phase borrows that are activated at $l$.