Pack u128 in the compiler to mitigate new alignment
This is based on #116672, adding a new `#[repr(packed(8))]` wrapper on `u128` to avoid changing any of the compiler's size assertions. This is needed in two places:
* `SwitchTargets`, otherwise its `SmallVec<[u128; 1]>` gets padded up to 32 bytes.
* `LitKind::Int`, so that entire `enum` can stay 24 bytes.
* This change definitely has far-reaching effects though, since it's public.
Don't forget that the lifetime on hir types is `'tcx`
This PR just tracks the `'tcx` lifetime to wherever the original objects actually have that lifetime. This code is needed for https://github.com/rust-lang/rust/pull/107606 (now #120131) so that `ast_ty_to_ty` can invoke `lit_to_const` on an argument passed to it. Currently the argument is `&hir::Ty<'_>`, but after this PR it is `&'tcx hir::Ty<'tcx>`.
Move async closure parameters into the resultant closure's future eagerly
Move async closure parameters into the closure's resultant future eagerly.
Before, we used to desugar `async |p1, p2, ..| { body }` as `|p1, p2, ..| { || async { body } }`. Now, we desugar the above like `|p1, p2, ..| { async move { let p1 = p1; let p2 = p2; ... body } }`. This mirrors the same desugaring that `async fn` does with its parameter types, and the compiler literally uses the same code via a shared helper function.
This removes the necessity for E0708, since now expressions like `async |x: i32| { x }` will not give you confusing borrow errors.
This does *not* fix the case where async closures have self-borrows. This will come with a general implementation of async closures, which is still in the works.
r? oli-obk
One consequence is that errors returned by
`maybe_new_parser_from_source_str` now must be consumed, so a bunch of
places that previously ignored those errors now cancel them. (Most of
them explicitly dropped the errors before. I guess that was to indicate
"we are explicitly ignoring these", though I'm not 100% sure.)
rustc_span: Optimize syntax context comparisons
Including comparisons with root context.
- `eq_ctxt` doesn't require retrieving full `SpanData`, or taking the span interner lock twice.
- Checking `SyntaxContext` for "rootness" is cheaper than extracting a full outer `ExpnData` for it and checking *it* for rootness.
The internal lint for `eq_ctxt` is also tweaked to detect `a.ctxt() != b.ctxt()` in addition to `a.ctxt() == b.ctxt()`.
Fix scoping for let chains in match guards
If let guards were previously represented as a different type of guard in HIR and THIR. This meant that let chains in match guards were not handled correctly because they were treated exactly like normal guards.
- Remove `hir::Guard` and `thir::Guard`.
- Make the scoping different between normal guards and if let guards also check for let chains.
closes#118593
Make closures carry their own ClosureKind
Right now, we use the "`movability`" field of `hir::Closure` to distinguish a closure and a coroutine. This is paired together with the `CoroutineKind`, which is located not in the `hir::Closure`, but the `hir::Body`. This is strange and redundant.
This PR introduces `ClosureKind` with two variants -- `Closure` and `Coroutine`, which is put into `hir::Closure`. The `CoroutineKind` is thus removed from `hir::Body`, and `Option<Movability>` no longer needs to be a stand-in for "is this a closure or a coroutine".
r? eholk
Clairify `ast::PatKind::Struct` presese of `..` by using an enum instead of a bool
The bool is mainly used for when a `..` is present, but it is also set on recovery to avoid errors. The doc comment not describes both of these cases.
See cee794ee98/compiler/rustc_parse/src/parser/pat.rs (L890-L897) for the only place this is constructed.
r? ``@compiler-errors``
Add support for `for await` loops
This adds support for `for await` loops. This includes parsing, desugaring in AST->HIR lowering, and adding some support functions to the library.
Given a loop like:
```rust
for await i in iter {
...
}
```
this is desugared to something like:
```rust
let mut iter = iter.into_async_iter();
while let Some(i) = loop {
match core::pin::Pin::new(&mut iter).poll_next(cx) {
Poll::Ready(i) => break i,
Poll::Pending => yield,
}
} {
...
}
```
This PR also adds a basic `IntoAsyncIterator` trait. This is partly for symmetry with the way `Iterator` and `IntoIterator` work. The other reason is that for async iterators it's helpful to have a place apart from the data structure being iterated over to store state. `IntoAsyncIterator` gives us a good place to do this.
I've gated this feature behind `async_for_loop` and opened #118898 as the feature tracking issue.
r? `@compiler-errors`
Uplift `TypeAndMut` and `ClosureKind` to `rustc_type_ir`
Uplifts `TypeAndMut` and `ClosureKind`
I know I said I was just going to get rid of `TypeAndMut` (https://github.com/rust-lang/types-team/issues/124) but I think this is much simpler, lol
r? `@jackh726` or `@lcnr`
Renamings:
- find -> opt_hir_node
- get -> hir_node
- find_by_def_id -> opt_hir_node_by_def_id
- get_by_def_id -> hir_node_by_def_id
Fix rebase changes using removed methods
Use `tcx.hir_node_by_def_id()` whenever possible in compiler
Fix clippy errors
Fix compiler
Apply suggestions from code review
Co-authored-by: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Add FIXME for `tcx.hir()` returned type about its removal
Simplify with with `tcx.hir_node_by_def_id`
Add lint against ambiguous wide pointer comparisons
This PR is the resolution of https://github.com/rust-lang/rust/issues/106447 decided in https://github.com/rust-lang/rust/issues/117717 by T-lang.
## `ambiguous_wide_pointer_comparisons`
*warn-by-default*
The `ambiguous_wide_pointer_comparisons` lint checks comparison of `*const/*mut ?Sized` as the operands.
### Example
```rust
let ab = (A, B);
let a = &ab.0 as *const dyn T;
let b = &ab.1 as *const dyn T;
let _ = a == b;
```
### Explanation
The comparison includes metadata which may not be expected.
-------
This PR also drops `clippy::vtable_address_comparisons` which is superseded by this one.
~~One thing: is the current naming right? `invalid` seems a bit too much.~~
Fixes https://github.com/rust-lang/rust/issues/117717
This is an extension of the previous commit. It means the output of
something like this:
```
stringify!(let a: Vec<u32> = vec![];)
```
goes from this:
```
let a: Vec<u32> = vec![] ;
```
With this PR, it now produces this string:
```
let a: Vec<u32> = vec![];
```
detects redundant imports that can be eliminated.
for #117772 :
In order to facilitate review and modification, split the checking code and
removing redundant imports code into two PR.
