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Remove implementation details

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Nilstrieb 2022-11-05 16:22:37 +01:00 committed by Joshua Nelson
parent 4c1505600c
commit 062dd31e33
1 changed files with 2 additions and 31 deletions
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src/query.md
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@ -175,8 +175,8 @@ Defining a query takes place in two steps:
To declare the query name and arguments, you simply add an entry to
the big macro invocation in [`compiler/rustc_middle/src/query/mod.rs`][query-mod].
Then you need to add a documentation comment to it with some _internal_ description.
Then, provide the `desc` attribute which contains a short description of the query.
This description is shown to the user in query cycles.
Then, provide the `desc` attribute which contains a _user-facing_ description of the query.
The `desc` attribute is shown to the user in query cycles.
This looks something like:
@ -237,35 +237,6 @@ which is used to cheaply modify MIR in place. See the definition
of `Steal` for more details. New uses of `Steal` should **not** be
added without alerting `@rust-lang/compiler`.
### Query structs and descriptions
For each query, the `rustc_queries` macro will generate a "query struct"
named after the query. This struct is a kind of placeholder
describing the query. Each query struct implements the
[`self::config::QueryConfig`][QueryConfig] trait, which has associated types for the
key/value of that particular query. Basically the code generated looks something
like this:
```rust,ignore
// Dummy struct representing a particular kind of query:
pub struct type_of<'tcx> { data: PhantomData<&'tcx ()> }
impl<'tcx> QueryConfig for type_of<'tcx> {
type Key = DefId;
type Value = Ty<'tcx>;
const NAME: QueryName = QueryName::type_of;
const CATEGORY: ProfileCategory = ProfileCategory::Other;
}
```
There is an additional trait with more methods called
[`self::config::QueryDescription`][QueryDescription]. This trait contains a few
extra methods which are used by the query system.
[QueryConfig]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_query_system/query/config/trait.QueryConfig.html
[QueryDescription]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_query_system/query/config/trait.QueryDescription.html
## External links
Related design ideas, and tracking issues: