Rust 1.34.0

When specifying dependencies in your , use the key to let Cargo know that you wish to fetch the crate from the alternate registry:

As a crate author, if you wish to publish your crate to an alternate registry, you first need to save the authentication token into with the command:

You can then use the flag to indicate which registry to use when publishing:

There is documentation on how to run your own registry. Procedural macro crates would instead use strings for specifying syntaxes like this, e.g.

With this Rust release, custom attributes now accept arbitrary token streams in , bringing them on par with macros. If you’re the author of a procedural macro crate, please check if your custom attributes have unnecessary strings in their syntax and if they can be better expressed with token streams.

Source: blog.rust-lang.org