A more robust solution to finding where to place use suggestions was added.
The algorithm uses the AST to find the span for the suggestion so we pass this span
down to the HIR during lowering and use it.

Signed-off-by: Miguel Guarniz <[email protected]>

…um, r=davidtwco

Stabilize `derive_default_enum`

This stabilizes `#![feature(derive_default_enum)]`, as proposed in [RFC 3107](rust-lang/rfcs#3107) and tracked in rust-lang#87517. In short, it permits you to `#[derive(Default)]` on `enum`s, indicating what the default should be by placing a `#[default]` attribute on the desired variant (which must be a unit variant in the interest of forward compatibility).

```````@rustbot``````` label +S-waiting-on-review +T-lang

Create (unstable) 2024 edition

[On Zulip](https://rust-lang.zulipchat.com/#narrow/stream/213817-t-lang/topic/Deprecating.20macro.20scoping.20shenanigans/near/272860652), there was a small aside regarding creating the 2024 edition now as opposed to later. There was a reasonable amount of support and no stated opposition.

This change creates the 2024 edition in the compiler and creates a prelude for the 2024 edition. There is no current difference between the 2021 and 2024 editions. Cargo and other tools will need to be updated separately, as it's not in the same repository. This change permits the vast majority of work towards the next edition to proceed _now_ instead of waiting until 2024.

For sanity purposes, I've merged the "hello" UI tests into a single file with multiple revisions. Otherwise we'd end up with a file per edition, despite them being essentially identical.

````@rustbot```` label +T-lang +S-waiting-on-review

Not sure on the relevant team, to be honest.

Check var scope if it exist

Fixes rust-lang#92893.

Added helper function to check the scope of a variable, if it doesn't have a scope call delay_span_bug, which avoids us trying to get a block/scope that doesn't exist.

Had to increase `ROOT_ENTRY_LIMIT` was getting tidy error

…cement, r=pnkfelix

remove find_use_placement

A more robust solution to finding where to place use suggestions was added in rust-lang#94584.
The algorithm uses the AST to find the span for the suggestion so we pass this span
down to the HIR during lowering and use it instead of calling `find_use_placement`

Fixes rust-lang#94941

only downgrade selection Error -> Ambiguous if type error is in predicate

That is, we don't care if there's a TypeError type in the ParamEnv.

Fixes rust-lang#95408

…ylan-DPC

couple of clippy::complexity fixes

remove function parameters only used in recursion

…Dylan-DPC

[test] Add test cases of untested functions for BTreeSet

- add [`is_superset()`](https://doc.rust-lang.org/std/collections/struct.BTreeSet.html#method.is_superset) and [`remove()`](https://doc.rust-lang.org/std/collections/struct.BTreeSet.html#method.remove) test cases for BTreeSet since these functions has no test cases.

Use u32 instead of i32 for futexes.

This changes futexes from i32 to u32. The [Linux man page](https://man7.org/linux/man-pages/man2/futex.2.html) uses `uint32_t` for them, so I'm not sure why I used i32 for them. Maybe because I first used them for thread parkers, where I used -1, 0, and 1 as the states.

(Wasm's `memory.atomic.wait32` does use `i32`, because wasm doesn't support `u32`.)

It doesn't matter much, but using the unsigned type probably results in fewer surprises when shifting bits around or using comparison operators.

r? ```@Amanieu```

docs: Update tests chapter for Termination stabilization

A small update for the docs of `#[test]` functions as a result of the `Termination` stabilization in rust-lang#93840.

…nd-remove-unnecessary-nested-blocks, r=compiler-errors

Refactor: Use `format-args-capture` and remove unnecessary nested blocks in rustc_typeck