Returns true if the borrow represented by kind is
allowed to be split into separate Reservation and
Activation phases.
Determines if a given borrow is borrowing local data
This is called for all Yield expressions on movable generators
Encapsulates the idea of iterating over every borrow that involves a particular path
If place is a field projection, and the field is being projected from a closure type,
then returns the index of the field being projected. Note that this closure will always
be self in the current MIR, because that is the only time we directly access the fields
of a closure type.