7898: generate_function assist: infer return type r=JoshMcguigan a=JoshMcguigan
This PR makes two changes to the generate function assist:
1. Attempt to infer an appropriate return type for the generated function
2. If a return type is inferred, and that return type is not unit, don't render the snippet
```rust
fn main() {
let x: u32 = foo$0();
// ^^^ trigger the assist to generate this function
}
// BEFORE
fn foo() ${0:-> ()} {
todo!()
}
// AFTER (only change 1)
fn foo() ${0:-> u32} {
todo!()
}
// AFTER (change 1 and 2, note the lack of snippet around the return type)
fn foo() -> u32 {
todo!()
}
```
These changes are made as two commits, in case we want to omit change 2. I personally feel like it is a nice change, but I could understand there being some opposition.
#### Pros of change 2
If we are able to infer a return type, and especially if that return type is not the unit type, the return type is almost as likely to be correct as the argument names/types. I think this becomes even more true as people learn how this feature works.
#### Cons of change 2
We could never be as confident about the return type as we are about the function argument types, so it is more likely a user will want to change that. Plus it is a confusing UX to sometimes have the cursor highlight the return type after triggering this assist and sometimes not have that happen.
#### Why omit unit type?
The assumption is that if we infer the return type as unit, it is likely just because of the current structure of the code rather than that actually being the desired return type. However, this is obviously just a heuristic and will sometimes be wrong. But being wrong here just means falling back to the exact behavior that existed before this PR.
Co-authored-by: Josh Mcguigan <joshmcg88@gmail.com>
We probably should look into removing `xtask codegen` altogether. The
test workflow works perfectly for package.json config.
There are two things preventing that:
* Lint completions are generated on demand.
* Docs are not committed to the repository.
7891: Improve handling of rustc_private r=matklad a=DJMcNab
This PR changes how `rust-analyzer` handles `rustc_private`. In particular, packages now must opt-in to using `rustc_private` in `Cargo.toml`, by adding:
```toml
[package.metadata.rust-analyzer]
rustc_private=true
```
This means that depending on crates which also use `rustc_private` will be significantly improved, since their dependencies on the `rustc_private` crates will be resolved properly.
A similar approach could be used in #6714 to allow annotating that your package uses the `test` crate, although I have not yet handled that in this PR.
Additionally, we now only index the crates which are transitive dependencies of `rustc_driver` in the `rustcSource` directory. This should not cause any change in behaviour when using `rustcSource: "discover"`, as the source used then will only be a partial clone. However, if `rustcSource` pointing at a local checkout of rustc, this should significantly improve the memory usage and lower indexing time. This is because we avoids indexing all crates in `src/tools/`, which includes `rust-analyzer` itself.
Furthermore, we also prefer named dependencies over dependencies from `rustcSource`. This ensures that feature resolution for crates which are depended on by both `rustc` and your crate uses the correct set for analysing your crate.
See also [introductory zulip stream](https://rust-lang.zulipchat.com/#narrow/stream/185405-t-compiler.2Fwg-rls-2.2E0/topic/Fixed.20crate.20graphs.20and.20optional.20builtin.20crates/near/229086673)
I have tested this in [priroda](https://github.com/oli-obk/priroda/), and it provides a significant improvement to the development experience (once I give `miri` the required data in `Cargo.toml`)
Todo:
- [ ] Documentation
This is ready to review, and I will add documentation if this would be accepted (or if I get time to do so anyway)
Co-authored-by: Daniel McNab <36049421+DJMcNab@users.noreply.github.com>
