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nnethercote and others added 30 commits March 28, 2025 09:18
"Missing" patterns are possible in bare fn types (`fn f(u32)`) and
similar places. Currently these are represented in the AST with
`ast::PatKind::Ident` with no `by_ref`, no `mut`, an empty ident, and no
sub-pattern. This flows through to `{hir,thir}::PatKind::Binding` for
HIR and THIR.

This is a bit nasty. It's very non-obvious, and easy to forget to check
for the exceptional empty identifier case.

This commit adds a new variant, `PatKind::Missing`, to do it properly.

The process I followed:
- Add a `Missing` variant to `{ast,hir,thir}::PatKind`.
- Chang `parse_param_general` to produce `ast::PatKind::Missing`
  instead of `ast::PatKind::Missing`.
- Look through `kw::Empty` occurrences to find functions where an
  existing empty ident check needs replacing with a `PatKind::Missing`
  check: `print_param`, `check_trait_item`, `is_named_param`.
- Add a `PatKind::Missing => unreachable!(),` arm to every exhaustive
  match identified by the compiler.
- Find which arms are actually reachable by running the test suite,
  changing them to something appropriate, usually by looking at what
  would happen to a `PatKind::Ident`/`PatKind::Binding` with no ref, no
  `mut`, an empty ident, and no subpattern.

Quite a few of the `unreachable!()` arms were never reached. This makes
sense because `PatKind::Missing` can't happen in every pattern, only
in places like bare fn tys and trait fn decls.

I also tried an alternative approach: modifying `ast::Param::pat` to
hold an `Option<P<Pat>>` instead of a `P<Pat>`, but that quickly turned
into a very large and painful change. Adding `PatKind::Missing` is much
easier.
In the AST, currently we use `BinOpKind` within `ExprKind::AssignOp` and
`AssocOp::AssignOp`, even though this allows some nonsensical
combinations. E.g. there is no `&&=` operator. Likewise for HIR and
THIR.

This commit introduces `AssignOpKind` which only includes the ten
assignable operators, and uses it in `ExprKind::AssignOp` and
`AssocOp::AssignOp`. (And does similar things for `hir::ExprKind` and
`thir::ExprKind`.) This avoids the possibility of nonsensical
combinations, as seen by the removal of the `bug!` case in
`lang_item_for_binop`.

The commit is mostly plumbing, including:
- Adds an `impl From<AssignOpKind> for BinOpKind` (AST) and `impl
  From<AssignOp> for BinOp` (MIR/THIR).
- `BinOpCategory` can now be created from both `BinOpKind` and
  `AssignOpKind`.
- Replaces the `IsAssign` type with `Op`, which has more information and
  a few methods.
- `suggest_swapping_lhs_and_rhs`: moves the condition to the call site,
  it's easier that way.
- `check_expr_inner`: had to factor out some code into a separate
  method.

I'm on the fence about whether avoiding the nonsensical combinations is
worth the extra code.
Add new `PatKind::Missing` variants

To avoid some ugly uses of `kw::Empty` when handling "missing" patterns, e.g. in bare fn tys. Helps with #137978. Details in the individual commits.

r? ``@oli-obk``
…rpolated, r=petrochenkov

Remove `Nonterminal` and `TokenKind::Interpolated`

A third attempt at this; the first attempt was #96724 and the second was #114647.

r? `@ghost`
By replacing them with `{Open,Close}{Param,Brace,Bracket,Invisible}`.

PR #137902 made `ast::TokenKind` more like `lexer::TokenKind` by
replacing the compound `BinOp{,Eq}(BinOpToken)` variants with fieldless
variants `Plus`, `Minus`, `Star`, etc. This commit does a similar thing
with delimiters. It also makes `ast::TokenKind` more similar to
`parser::TokenType`.

This requires a few new methods:
- `TokenKind::is_{,open_,close_}delim()` replace various kinds of
  pattern matches.
- `Delimiter::as_{open,close}_token_kind` are used to convert
  `Delimiter` values to `TokenKind`.

Despite these additions, it's a net reduction in lines of code. This is
because e.g. `token::OpenParen` is so much shorter than
`token::OpenDelim(Delimiter::Parenthesis)` that many multi-line forms
reduce to single line forms. And many places where the number of lines
doesn't change are still easier to read, just because the names are
shorter, e.g.:
```
-   } else if self.token != token::CloseDelim(Delimiter::Brace) {
+   } else if self.token != token::CloseBrace {
```
apparently it doesn't really use the asm parsing at present, so this may work?
Keep the `P` constructor function for now, to minimize immediate churn.

All the `into_inner` calls are removed, which is nice.
So they match the order of the parts in the source code, e.g.:
```
struct Foo<T, U> { t: T, u: U }
       <-><----> <------------>
       /   |       \
   ident generics  variant_data
```
Reorder `ast::ItemKind::{Struct,Enum,Union}` fields.

So they match the order of the parts in the source code, e.g.:
```
struct Foo<T, U> { t: T, u: U }
       <-><----> <------------>
       /   |       \
   ident generics  variant_data
```

r? `@fee1-dead`
Reduce `ast::ptr::P` to a typedef of `Box`

As per the MCP at rust-lang/compiler-team#878.

r? `@fee1-dead`
"{{root}}" is an internal-only name, and cannot appear in Rust code
being formatted.
Rollup of 9 pull requests

Successful merges:

 - rust-lang/rust#142331 (Add `trim_prefix` and `trim_suffix` methods for both `slice` and `str` types.)
 - rust-lang/rust#142491 (Rework #[cold] attribute parser)
 - rust-lang/rust#142494 (Fix missing docs in `rustc_attr_parsing`)
 - rust-lang/rust#142495 (Better template for `#[repr]` attributes)
 - rust-lang/rust#142497 (Fix random failure when JS code is executed when the whole file was not read yet)
 - rust-lang/rust#142575 (Ensure copy* intrinsics also perform the static self-init checks)
 - rust-lang/rust#142650 (Refactor Translator)
 - rust-lang/rust#142713 (mbe: Refactor transcription)
 - rust-lang/rust#142755 (rustdoc: Remove `FormatRenderer::cache`)

r? `@ghost`
`@rustbot` modify labels: rollup
…iscross

Implement parsing of pinned borrows

This PR implements part of #130494.

EDIT: It introduces `&pin mut $place` and `&pin const $place` as sugars for `std::pin::pin!($place)` and its shared reference equivalent, except that `$place` will not be moved when borrowing. The borrow check will be in charge of enforcing places cannot be moved or mutably borrowed since being pinned till dropped.

### Implementation steps:
- [x] parse the `&pin mut $place` and `&pin const $place` syntaxes
- [ ] borrowck of `&pin mut|const`
- [ ] support autoref of `&pin mut|const` when needed
New const traits syntax

This PR only affects the AST and doesn't actually change anything semantically.

All occurrences of `~const` outside of libcore have been replaced by `[const]`. Within libcore we have to wait for rustfmt to be bumped in the bootstrap compiler. This will happen "automatically" (when rustfmt is run) during the bootstrap bump, as rustfmt converts `~const` into `[const]`. After this we can remove the `~const` support from the parser

Caveat discovered during impl: there is no legacy bare trait object recovery for `[const] Trait` as that snippet in type position goes down the slice /array parsing code and will error

r? ``@fee1-dead``

cc ``@nikomatsakis`` ``@traviscross`` ``@compiler-errors``
Remove let_chains unstable feature

Per rust-lang/rust#53667 (comment) (but then I also noticed rust-lang/rust#140722)

This replaces the feature gate with a parser error that says let chains require 2024.

A lot of tests were using the unstable feature. I either added edition:2024 to the test or split out the parts that require 2024.
@mohe2015 mohe2015 changed the title Html extractor formatting Add some macro formatters Sep 1, 2025
mohe2015 and others added 12 commits September 2, 2025 00:50
add span to struct pattern rest (..)

Struct pattern rest (`..`) did not retain span information compared to normal fields. This patch adds span information for it.

The motivation of this patch comes from when I implemented this PR for Clippy: rust-lang/rust-clippy#15000 (comment)

It is possible to get the span of the Et cetera in a bit roundabout way, but I thought this would be nicer.
fix a constness ordering bug in rustfmt

Normally, changes to rustfmt go into the separate repo. But, in this case, the bug is introduced in a local change and therefore isn't present in the rustfmt repo.

Related to: rust-lang/rust#146071
Fixes rust-lang#6619.
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