diff options
Diffstat (limited to 'vendor/static_assertions/README.md')
| -rw-r--r-- | vendor/static_assertions/README.md | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/vendor/static_assertions/README.md b/vendor/static_assertions/README.md new file mode 100644 index 000000000..bca222ed5 --- /dev/null +++ b/vendor/static_assertions/README.md @@ -0,0 +1,188 @@ +[](https://github.com/nvzqz/static-assertions-rs) + +<div align="center"> + <a href="https://crates.io/crates/static_assertions"> + <img src="https://img.shields.io/crates/v/static_assertions.svg" alt="Crates.io"> + <img src="https://img.shields.io/crates/d/static_assertions.svg" alt="Downloads"> + </a> + <a href="https://travis-ci.org/nvzqz/static-assertions-rs"> + <img src="https://travis-ci.org/nvzqz/static-assertions-rs.svg?branch=master" alt="Build Status"> + </a> + <img src="https://img.shields.io/badge/rustc-^1.37.0-blue.svg" alt="rustc ^1.37.0"> + <br> + <a href="https://www.patreon.com/nvzqz"> + <img src="https://c5.patreon.com/external/logo/become_a_patron_button.png" alt="Become a Patron!" height="35"> + </a> + <a href="https://www.paypal.me/nvzqz"> + <img src="https://buymecoffee.intm.org/img/button-paypal-white.png" alt="Buy me a coffee" height="35"> + </a> +</div> + +Compile-time assertions for Rust, brought to you by +[Nikolai Vazquez](https://twitter.com/NikolaiVazquez). + +This library lets you ensure correct assumptions about constants, types, and +more. See the [docs] and [FAQ](#faq) for more info! + +## Installation + +This crate is available +[on crates.io](https://crates.io/crates/static_assertions) and can be used by +adding the following to your project's +[`Cargo.toml`](https://doc.rust-lang.org/cargo/reference/manifest.html): + +```toml +[dependencies] +static_assertions = "1.1.0" +``` + +and this to your crate root (`main.rs` or `lib.rs`): + +```rust +#[macro_use] +extern crate static_assertions; +``` + +## Usage + +This crate exposes the following macros: +- [`assert_cfg!`] +- [`assert_eq_align!`] +- [`assert_eq_size!`] +- [`assert_eq_size_ptr!`] +- [`assert_eq_size_val!`] +- [`assert_fields!`] +- [`assert_impl_all!`] +- [`assert_impl_any!`] +- [`assert_impl_one!`] +- [`assert_not_impl_all!`] +- [`assert_not_impl_any!`] +- [`assert_obj_safe!`] +- [`assert_trait_sub_all!`] +- [`assert_trait_super_all!`] +- [`assert_type_eq_all!`] +- [`assert_type_ne_all!`] +- [`const_assert!`] +- [`const_assert_eq!`] +- [`const_assert_ne!`] + +## FAQ + +- **Q:** When would I want to use this? + + **A:** This library is useful for when wanting to ensure properties of + constants, types, and traits. + + Basic examples: + + - With the release of 1.39, `str::len` can be called in a `const` + context. Using [`const_assert!`], one can check that a string generated from + elsewhere is of a given size: + + ```rust + const DATA: &str = include_str!("path/to/string.txt"); + + const_assert!(DATA.len() < 512); + ``` + + - Have a type that absolutely must implement certain traits? With + [`assert_impl_all!`], one can ensure this: + + ```rust + struct Foo { + value: // ... + } + + assert_impl_all!(Foo: Send, Sync); + ``` + +- **Q:** How can I contribute? + + **A:** A couple of ways! You can: + + - Attempt coming up with some form of static analysis that you'd like to see + implemented. Create a [new issue] and describe how you'd imagine your + assertion to work, with example code to demonstrate. + + - Implement your own static assertion and create a [pull request]. + + - Give feedback. What are some pain points? Where is it unpleasant? + + - Write docs. If you're familiar with how this library works, sharing your + knowledge with the rest its users would be great! + +- **Q:** Will this affect my compiled binary? + + **A:** Nope! There is zero runtime cost to using this because all checks are + at compile-time, and so no code is emitted to run. + +- **Q:** Will this affect my compile times? + + **A:** Likely not by anything perceivable. If this is a concern, this library + can be put in `dev-dependencies`: + + ```toml + [dev-dependencies] + static_assertions = "1.1.0" + ``` + + and then assertions can be conditionally run behind `#[cfg(test)]`: + + ```rust + #[cfg(test)] + const_assert_eq!(MEANING_OF_LIFE, 42); + ``` + + However, the assertions will only be checked when running `cargo test`. This + somewhat defeats the purpose of catching false static conditions up-front with + a compilation failure. + +- **Q:** What is `const _`? + + **A:** It's a way of creating an unnamed constant. This is used so that macros + can be called from a global scope without requiring a scope-unique label. This + library makes use of the side effects of evaluating the `const` expression. + See the feature's + [tracking issue](https://github.com/rust-lang/rust/issues/54912) + and + [issue #1](https://github.com/nvzqz/static-assertions-rs/issues/1) + for more info. + +## Changes + +See [`CHANGELOG.md`](https://github.com/nvzqz/static-assertions-rs/blob/master/CHANGELOG.md) +for a complete list of what has changed from one version to another. + +## License + +This project is released under either: + +- [MIT License](https://github.com/nvzqz/static-assertions-rs/blob/master/LICENSE-MIT) + +- [Apache License (Version 2.0)](https://github.com/nvzqz/static-assertions-rs/blob/master/LICENSE-APACHE) + +at your choosing. + +[new issue]: https://github.com/nvzqz/static-assertions-rs/issues/new +[pull request]: https://github.com/nvzqz/static-assertions-rs/pulls +[docs]: https://docs.rs/static_assertions + +[`assert_cfg!`]: https://docs.rs/static_assertions/1.1.0/static_assertions/macro.assert_cfg.html +[`assert_eq_align!`]: https://docs.rs/static_assertions/1.1.0/static_assertions/macro.assert_eq_align.html +[`assert_eq_size!`]: https://docs.rs/static_assertions/1.1.0/static_assertions/macro.assert_eq_size.html +[`assert_eq_size_ptr!`]: https://docs.rs/static_assertions/1.1.0/static_assertions/macro.assert_eq_size_ptr.html +[`assert_eq_size_val!`]: https://docs.rs/static_assertions/1.1.0/static_assertions/macro.assert_eq_size_val.html +[`assert_fields!`]: https://docs.rs/static_assertions/1.1.0/static_assertions/macro.assert_fields.html +[`assert_impl_all!`]: https://docs.rs/static_assertions/1.1.0/static_assertions/macro.assert_impl_all.html +[`assert_impl_any!`]: https://docs.rs/static_assertions/1.1.0/static_assertions/macro.assert_impl_any.html +[`assert_impl_one!`]: https://docs.rs/static_assertions/1.1.0/static_assertions/macro.assert_impl_one.html +[`assert_not_impl_all!`]: https://docs.rs/static_assertions/1.1.0/static_assertions/macro.assert_not_impl_all.html +[`assert_not_impl_any!`]: https://docs.rs/static_assertions/1.1.0/static_assertions/macro.assert_not_impl_any.html +[`assert_obj_safe!`]: https://docs.rs/static_assertions/1.1.0/static_assertions/macro.assert_obj_safe.html +[`assert_trait_sub_all!`]: https://docs.rs/static_assertions/1.1.0/static_assertions/macro.assert_trait_sub_all.html +[`assert_trait_super_all!`]: https://docs.rs/static_assertions/1.1.0/static_assertions/macro.assert_trait_super_all.html +[`assert_type_eq_all!`]: https://docs.rs/static_assertions/1.1.0/static_assertions/macro.assert_type_eq_all.html +[`assert_type_ne_all!`]: https://docs.rs/static_assertions/1.1.0/static_assertions/macro.assert_type_ne_all.html +[`const_assert!`]: https://docs.rs/static_assertions/1.1.0/static_assertions/macro.const_assert.html +[`const_assert_eq!`]: https://docs.rs/static_assertions/1.1.0/static_assertions/macro.const_assert_eq.html +[`const_assert_ne!`]: https://docs.rs/static_assertions/1.1.0/static_assertions/macro.const_assert_ne.html |