#proc-macro #async #async-trait #gats #existential-types

macro real-async-trait

A proc macro that uses experimental features to work around type erasure for async traits

3 releases

0.0.2 Jul 14, 2020
0.0.1 Jul 14, 2020
0.0.0 Jul 14, 2020

#280 in Asynchronous

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Build Status Crates.io Documentation

This crate provides a proof-of-concept proc macro attribute that allows async traits to be possible, without wrapping everything in a Box and erase the types. This is made possible due to experimental generic_associated_types feature, as well as the unstable type_alias_impl_trait feature.


The generic_associated_types feature is not unstable, but an "incomplete" experimental feature; rustc even gives you a warning when using it. Don't use this in production code. At the moment it's probably a better idea to use a type-erased async trait attribute proc macro, such as Dtolnay's async-trait crate, or a similar one. That said, it'd be awesome both for me and for the rust compiler if you could test this, find something that's missing in the compiler or here, and file an issue.


Licensed under either of

at your option.


Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.


~20K SLoC