rust - 如何在 Rust 2018 中惯用地为箱子起别名？

Question

我有一个 crate foo_sys。在 Rust 2015 中，为了方便起见，我使用 extern crate foo_sys as foo，但在 Rust 2018 中，不再需要 extern crate，我不想仅将其用于别名.当删除 extern crate 时，我得到

error[E0463]: can't find crate for foo

Answer 1

这可以通过 rename-dependency 来实现 cargo 功能，available in Rust 1.31 .使用此功能，可以为依赖项提供包属性:

The rename-dependency feature allows you to import a dependency with a different name from the source. This can be useful in a few scenarios:

• Depending on crates with the same name from different registries.
• Depending on multiple versions of a crate.
• Avoid needing extern crate foo as bar in Rust source.

代替写作

[dependencies]
foo_sys = "0.2"

可以将 package 键添加到 Cargo.toml 中的依赖项:

[dependencies]
foo = { package = "foo_sys", version = "0.2" }

警告:Cargo prior to Rust 1.26.0 may download the wrong dependency使用此功能时!