Summary:
A simple intraprocedural analysis that tracks when a storage location is read or deleted.
For now, this works only with local variable storage locations; field and array accesses are ignored.
In order to test this, I added a new "use-after-lifetime" warning. It complains when a variable is read or deleted after it has already been deleted.
Reviewed By: jeremydubreil
Differential Revision: D6961314
fbshipit-source-id: 75e95a2