SourceMap is now in the root of all rustc-specific crates, syntax_pos,
so there's no need for the trait object to decouple the dependencies
between librustc_errors and libsyntax as was needed previously.
Port erased cleanup
Just realised that the changes I made in #65965 were removed after the move of all error codes so here it is. I made them into separate commits to make the history look better this time.
r? @Mark-Simulacrum
Push `ast::{ItemKind, ImplItemKind}::OpaqueTy` hack down into lowering
We currently have a hack in the form of `ast::{ItemKind, ImplItemKind}::OpaqueTy` which is constructed literally when you write `type Alias = impl Trait;` but not e.g. `type Alias = Vec<impl Trait>;`. Per https://github.com/rust-lang/rfcs/pull/2515, this needs to change to allow `impl Trait` in nested positions. This PR achieves this change for the syntactic aspect but not the semantic one, which will require changes in lowering and def collection. In the interim, `TyKind::opaque_top_hack` is introduced to avoid knock-on changes in lowering, collection, and resolve. These hacks can then be removed and fixed one by one until the desired semantics are supported.
r? @varkor
This does not update the use sites or delete the now unnecessary
SourceMapper trait, to allow git to interpret the file move as a rename
rather than a new file.
This is a bit unfortunate, but code needs to be able to fatally error
early on (in particular, syntax_pos after we move SourceMap there). It's
also a tiny bit of code, which means it's ultimately not that bad.
Rollup of 12 pull requests
Successful merges:
- #65557 (rename Error::iter_chain() and remove Error::iter_sources())
- #66013 (Avoid hashing the key twice in `get_query()`.)
- #66306 (Remove cannot mutate statics in initializer of another static error)
- #66338 (Update mdbook.)
- #66388 (Do not ICE on recovery from unmet associated type bound obligation)
- #66390 (Fix ICE when trying to suggest `Type<>` instead of `Type()`)
- #66391 (Do not ICE in `if` without `else` in `async fn`)
- #66398 (Remove some stack frames from `.async` calls)
- #66410 (miri: helper methods for max values of machine's usize/isize)
- #66418 (Link to tracking issue in HIR const-check error code description)
- #66419 (Don't warn labels beginning with `_` on unused_labels lint)
- #66428 (Cleanup unused function)
Failed merges:
r? @ghost
Link to tracking issue in HIR const-check error code description
This is a follow up to #66170 that addresses [this comment](https://github.com/rust-lang/rust/pull/66170#discussion_r344021268).
As an aside, the only other error code whose description uses the phrase "tracking issue" is `E0202`. We may want to come up with standards around this, especially since error codes are now centralized and easier to keep track of (thanks @GuillaumeGomez).
r? @estebank (since they +1'ed the comment)
Remove some stack frames from `.async` calls
The `Context` argument is currently smuggled through TLS for
async-generated futures. The current infrastructure is closure-based,
and results in an extra 6 stack frames when .awaiting an async-generated
future!
```
12: foo::async_b::{{closure}}
at src/main.rs:10
13: <std::future::GenFuture<T> as core::future::future::Future>::poll::{{closure}}
at /rustc/4560ea788cb760f0a34127156c78e2552949f734/src/libstd/future.rs:43
14: std::future::set_task_context
at /rustc/4560ea788cb760f0a34127156c78e2552949f734/src/libstd/future.rs:79
15: <std::future::GenFuture<T> as core::future::future::Future>::poll
at /rustc/4560ea788cb760f0a34127156c78e2552949f734/src/libstd/future.rs:43
16: std::future::poll_with_tls_context::{{closure}}
at /rustc/4560ea788cb760f0a34127156c78e2552949f734/src/libstd/future.rs:121
17: std::future::get_task_context
at /rustc/4560ea788cb760f0a34127156c78e2552949f734/src/libstd/future.rs:111
18: std::future::poll_with_tls_context
at /rustc/4560ea788cb760f0a34127156c78e2552949f734/src/libstd/future.rs:121
19: foo::async_a::{{closure}}
at src/main.rs:6
```
While the long (medium?) term solution is to remove the use of TLS
entirely, we can improve things a bit in the meantime. In particular,
this commit does 2 things:
1. `get_task_context` has been inlined into `poll_with_tls_context`,
removing 2 frames (16 and 17 above).
2. `set_task_context` now returns a guard type that resets the TLS
rather than taking a closure, removing 2 frames (13 and 14 above).
We can also remove frame 18 by removing `poll_with_tls_context` in favor
of a `get_task_context` function which returns a guard, but that
requires adjusting the code generated for .await, so I've left that off
for now.
Fix ICE when trying to suggest `Type<>` instead of `Type()`
Fixes#66286, but the output has no span:
```
error[E0214]: parenthesized type parameters may only be used with a `Fn` trait
error: aborting due to previous error
For more information about this error, try `rustc --explain E0214`.
```
