Make casts of pointers to trait objects stricter
This is an attempt to `fix` https://github.com/rust-lang/rust/issues/120222 and https://github.com/rust-lang/rust/issues/120217.
This is done by adding restrictions on casting pointers to trait objects.
Before this PR the rules were as follows:
> When casting `*const X<dyn A>` -> `*const Y<dyn B>`, principal traits in `A` and `B` must refer to the same trait definition (or no trait).
With this PR the rules are changed to
> When casting `*const X<dyn Src>` -> `*const Y<dyn Dst>`
> - if `Dst` has a principal trait `DstP`,
> - `Src` must have a principal trait `SrcP`
> - `dyn SrcP` and `dyn DstP` must be the same type (modulo the trait object lifetime, `dyn T+'a` -> `dyn T+'b` is allowed)
> - Auto traits in `Dst` must be a subset of auto traits in `Src`
> - Not adhering to this is currently a FCW (warn-by-default + `FutureReleaseErrorReportInDeps`), instead of an error
> - if `Src` has a principal trait `Dst` must as well
> - this restriction will be removed in a follow up PR
This ensures that
1. Principal trait's generic arguments match (no `*const dyn Tr<A>` -> `*const dyn Tr<B>` casts, which are a problem for [#120222](https://github.com/rust-lang/rust/issues/120222))
2. Principal trait's lifetime arguments match (no `*const dyn Tr<'a>` -> `*const dyn Tr<'b>` casts, which are a problem for [#120217](https://github.com/rust-lang/rust/issues/120217))
3. No auto traits can be _added_ (this is a problem for arbitrary self types, see [this comment](https://github.com/rust-lang/rust/pull/120248#discussion_r1463835350))
Some notes:
- We only care about the metadata/last field, so you can still cast `*const dyn T` to `*const WithHeader<dyn T>`, etc
- The lifetime of the trait object itself (`dyn A + 'lt`) is not checked, so you can still cast `*mut FnOnce() + '_` to `*mut FnOnce() + 'static`, etc
- This feels fishy, but I couldn't come up with a reason it must be checked
The diagnostics are currently not great, to say the least, but as far as I can tell this correctly fixes the issues.
cc `@oli-obk` `@compiler-errors` `@lcnr`
Add an option to use "::" for the external crate prefix.
Fixes#11823 .
Hi I'm very new to rust-analyzer and not sure how the review process are. Can somebody take a look at this PR? thanks!
internal: Clean up runnable lsp extension
This feels like a natural addition to me, and also allows us to drop the expect-test hardcoding from the extension. Additionally, `cargoExtraArgs` is pointless, all the client will do is merge it with `cargoArgs` so the server can do that instead of delegating that to the client.
Improve dead code analysis
Fixes#120770
1. check impl items later if self ty is private although the trait method is public, cause we must use the ty firstly if it's private
2. mark the adt live if it appears in pattern, like generic argument, this implies the use of the adt
3. based on the above, we can handle the case that private adts impl Default, so that we don't need adding rustc_trivial_field_reads on Default, and the logic in should_ignore_item
r? ``@pnkfelix``
fix: Don't emit semantic diagnostics in files with a lot of syntax errors
These will only add to the noise when something very unexpected breaks or where parser recovery fails to kick in.
do not normalize `use foo::{self}` to `use foo`
It changes behaviour and can cause collisions. E.g. for the following snippet
```rs
mod foo {
pub mod bar {}
pub const bar: i32 = 8;
}
// transforming the below to `use foo::bar;` causes the error:
//
// the name `bar` is defined multiple times
use foo::bar::{self};
const bar: u32 = 99;
fn main() {
let local_bar = bar;
}
```
we still normalize
```rs
use foo::bar;
use foo::bar::{self};
```
to `use foo::bar;` because this cannot cause collisions.
See: https://github.com/rust-lang/rust-analyzer/pull/17140#issuecomment-2079189725
