The goal of this library is to be able to define types that cannot be implicitly dropped except in controlled situations.
A sketch of the design can be found here. The design does not handle branches, though it can be extended to do so. It's also a bit different from what I finally implemented
The idea is, that for a type that is marked
#[drop_protection], only functions annotated with
#[allowed_on_protected] can use these,
and each local must be dropped with a function marked
#[allowed_drop] before its scope finishes.
Current status: Is able to track such types and report on their usage. Maintains a list of what has been dropped properly to detect implicit drops.
Some missing (but planned) functionality:
- Cannot yet handle conditional drops, i.e. those in branches.
- Cannot yet handle any bindings other than a let binding
- Allowed functions cannot yet take &/&mut inputs
- Cannot yet mark method calls as allowed
To test, run
cargo run --example test, or even better
rustc examples/test.rs -L target (after building). The latter is better
because it will rebuild every time, and we're only interested in build output.