7b5176baea
* Upgrade all crates to the Rust 2021 edition
I've personally started using the new format strings for things like
`panic!("some message {foo}")` or similar and have been upgrading crates
on a case-by-case basis, but I think it probably makes more sense to go
ahead and blanket upgrade everything so 2021 features are always
available.
* Fix compile of the C API
* Fix a warning
* Fix another warning
This crate contains array-based data structures used by the core Cranelift code generator which represent a set of small ordered sets or maps.
These are not general purpose data structures that are somehow magically faster that the
standard library's BTreeSet and BTreeMap types.
The tradeoffs are different:
- Keys and values are expected to be small and copyable. We optimize for 32-bit types.
- A comparator object is used to compare keys, allowing smaller "context free" keys.
- Empty trees have a very small 32-bit footprint.
- All the trees in a forest can be cleared in constant time.