Allocate coeffect bits from pure towards unreachable
Summary:
This diff makes it so that
1) Each capability is positively given, i.e. ability to do something now gets a 1 bit instead of inability to do something previous getting 1 bit
2) COMMA separated coeffects now work as intended instead of getting promoted to the parent context
In order make sure `policied_of` cannot call `policied_shallow` and `policied_local`, I kept the escaping bit of `policied_of` in the runtime but it is not user denotable.
Reviewed By: jano
Differential Revision:
D29521836
fbshipit-source-id:
3ce736e7db969623a8e41d4ef8a9aa4984a541bf