hax adt into

This crate provides the adt_into procedural macro, allowing for mirroring data types with small variations.

This crate is used by the frontend of hax, where we need to mirror a big part of the data types defined by the Rust compiler. While the abstract syntax trees (ASTs) from the Rust compiler expose a lot of indirections (identifiers one should lookup, additional informations reachable only via interactive queries), hax exposes the same ASTs, removing indirections and inlining additional informations.

The adt_into derive macro can be used on structs and enums. adt_into then looks for another #[args(<GENERICS>, from: FROM_TYPE, state: STATE_TYPE as SOME_NAME)] attribute. Such an attribute means that the struct or enum mirrors the type FROM_TYPE, and that the transformation is carried along with a state of type STATE_TYPE that will be accessible via the name SOME_NAME.

An example is available in the tests folder.