Summary:
Fairly simple approach here:
- If the RHS of an assignment is a frontend-generated temporary variable, assume it transfers ownership to the LHS variable
- If the RHS of an assignment is a program variable, assume that the LHS variable is borrowing from it.
- If we try to access a variable that has borrowed from a variable that is now invalid, complain.
Reviewed By: jeremydubreil
Differential Revision: D7069947
fbshipit-source-id: 99b8ee2