DefinitelyInitializedPlaces tracks all places that are definitely
initialized upon reaching a particular point in the control flow
for a function.
EverInitializedPlaces tracks all places that might have ever been
initialized upon reaching a particular point in the control flow
for a function, without an intervening StorageDead.
MaybeInitializedPlaces tracks all places that might be
initialized upon reaching a particular point in the control flow
for a function.
MaybeUninitializedPlaces tracks all places that might be
uninitialized upon reaching a particular point in the control flow
for a function.