mirror
/
rustc-dev-guide
mirror of https://github.com/rust-lang/rustc-dev-guide.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Traits: Improve index layout, add chalk blurb

This commit is contained in:
Tyler Mandry 2018-10-24 21:22:57 -05:00
parent af51d27eac
commit e6ca31cb00
1 changed files with 33 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

51
src/traits/index.md
View File

@ -1,17 +1,26 @@
# Trait solving (new-style)
🚧 This chapter describes "new-style" trait solving. This is still in the
[process of being implemented][wg]; this chapter serves as a kind of
in-progress design document. If you would prefer to read about how the
current trait solver works, check out
[this other chapter](./resolution.html). (By the way, if you
would like to help in hacking on the new solver, you will find
instructions for getting involved in the
[Traits Working Group tracking issue][wg].) 🚧
> 🚧 This chapter describes "new-style" trait solving. This is still in the
> [process of being implemented][wg]; this chapter serves as a kind of
> in-progress design document. If you would prefer to read about how the
> current trait solver works, check out
> [this other chapter](./resolution.html). 🚧
>
> By the way, if you would like to help in hacking on the new solver, you will
> find instructions for getting involved in the
> [Traits Working Group tracking issue][wg].
[wg]: https://github.com/rust-lang/rust/issues/48416
Trait solving is based around a few key ideas:
The new-style trait solver is based on the work done in [chalk][chalk]. Chalk
recasts Rust's trait system explicitly in terms of logic programming. It does
this by "lowering" Rust code into a kind of logic program we can then execute
queries against.
You can read more about chalk itself in the
[Overview of Chalk](./chalk-overview.md) section.
Trait solving in rustc is based around a few key ideas:
- [Lowering to logic](./lowering-to-logic.html), which expresses
Rust traits in terms of standard logical terms.
@ -32,17 +41,23 @@ Trait solving is based around a few key ideas:
`Bar`?") once, and then apply that same result independently in many
different inference contexts.
Note: this is not a complete list of topics. See the sidebar for more.
> This is not a complete list of topics. See the sidebar for more.
## Ongoing work
The design of the new-style trait solving currently happens in two places:
* The [chalk][chalk] repository is where we experiment with new ideas and
designs for the trait system. It basically consists of a unit testing framework
for the correctness and feasibility of the logical rules defining the new-style
trait system. It also provides the [`chalk_engine`][chalk_engine] crate, which
defines the new-style trait solver used both in the unit testing framework and
in rustc.
* Once we are happy with the logical rules, we proceed to implementing them in
rustc. This mainly happens in [`librustc_traits`][librustc_traits].
**chalk**. The [chalk][chalk] repository is where we experiment with new ideas
and designs for the trait system. It primarily consists of two parts:
* a unit testing framework
for the correctness and feasibility of the logical rules defining the
new-style trait system.
* the [`chalk_engine`][chalk_engine] crate, which
defines the new-style trait solver used both in the unit testing framework
and in rustc.
**rustc**. Once we are happy with the logical rules, we proceed to
implementing them in rustc. This mainly happens in
[`librustc_traits`][librustc_traits].
[chalk]: https://github.com/rust-lang-nursery/chalk
[chalk_engine]: https://github.com/rust-lang-nursery/chalk/tree/master/chalk-engine