When we recover from a pattern parse error, or a pattern uses `..`, we keep track of that and affect resolution error for missing bindings that could have been provided by that pattern. We differentiate between `..` and parse recovery. We silence resolution errors likely caused by the pattern parse error.
```
error[E0425]: cannot find value `title` in this scope
--> $DIR/struct-pattern-with-missing-fields-resolve-error.rs:19:30
|
LL | println!("[{}]({})", title, url);
| ^^^^^ not found in this scope
|
note: `Website` has a field `title` which could have been included in this pattern, but it wasn't
--> $DIR/struct-pattern-with-missing-fields-resolve-error.rs:17:12
|
LL | / struct Website {
LL | | url: String,
LL | | title: Option<String> ,
| | ----- defined here
LL | | }
| |_-
...
LL | if let Website { url, .. } = website {
| ^^^^^^^^^^^^^^^^^^^ this pattern doesn't include `title`, which is available in `Website`
```
Fix#74863.
Change `AttrArgs::Eq` to a struct variant
Cleanups for simplifying https://github.com/rust-lang/rust/pull/131808
Basically changes `AttrArgs::Eq` to a struct variant and then avoids several matches on `AttrArgsEq` in favor of methods on it. This will make future refactorings simpler, as they can either keep methods or switch to field accesses without having to restructure code
Inline ExprPrecedence::order into Expr::precedence
The representation of expression precedence in rustc_ast has been an obstacle to further improvements in the pretty-printer (continuing from #119105 and #119427).
Previously the operation of *"does this expression have lower precedence than that one"* (relevant for parenthesis insertion in macro-generated syntax trees) consisted of 3 steps:
1. Convert `Expr` to `ExprPrecedence` using `.precedence()`
2. Convert `ExprPrecedence` to `i8` using `.order()`
3. Compare using `<`
As far as I can guess, the reason for the separation between `precedence()` and `order()` was so that both `rustc_ast::Expr` and `rustc_hir::Expr` could convert as straightforwardly as possible to the same `ExprPrecedence` enum, and then the more finicky logic performed by `order` could be present just once.
The mapping between `Expr` and `ExprPrecedence` was intended to be as straightforward as possible:
```rust
match self.kind {
ExprKind::Closure(..) => ExprPrecedence::Closure,
...
}
```
although there were exceptions of both many-to-one, and one-to-many:
```rust
ExprKind::Underscore => ExprPrecedence::Path,
ExprKind::Path(..) => ExprPrecedence::Path,
...
ExprKind::Match(_, _, MatchKind::Prefix) => ExprPrecedence::Match,
ExprKind::Match(_, _, MatchKind::Postfix) => ExprPrecedence::PostfixMatch,
```
Where the nature of `ExprPrecedence` becomes problematic is when a single expression kind might be associated with multiple different precedence levels depending on context (outside the expression) and contents (inside the expression). For example consider what is the precedence of an ExprKind::Closure `$closure`. Well, on the left-hand side of a binary operator it would need parentheses in order to avoid the trailing binary operator being absorbed into the closure body: `($closure) + Rhs`, so the precedence is something lower than that of `+`. But on the right-hand side of a binary operator, a closure is just a straightforward prefix expression like a unary op, which is a relatively high precedence level, higher than binops but lower than method calls: `Lhs + $closure` is fine without parens but `($closure).method()` needs them. But as a third case, if the closure contains an explicit return type, then the precedence is an even higher level than that, never needing parenthesization even in a binop left-hand side or method call: `|| -> bool { false } + Rhs` or `|| -> bool { false }.method()`.
You can see that trying to capture all of this resolution about expressions into `ExprPrecedence` violates the intention of `ExprPrecedence` being a straightforward one-to-one correspondence from each AST and HIR `ExprKind` variant. It would be possible to attempt that by doing stuff like `ExprPrecedence::Closure(Side::Leading, ReturnType::No)`, but I don't foresee the original envisioned benefit of the `precedence()`/`order()` distinction being retained in this approach. Instead I want to move toward a model that Syn has been using successfully. In Syn, there is a Precedence enum but it differs from rustc in the following ways:
- There are [relatively few variants](https://github.com/dtolnay/syn/blob/2.0.87/src/precedence.rs#L11-L47) compared to rustc's `ExprPrecedence`. For example there is no distinction at the precedence level between returns and closures, or between loops and method calls.
- We distinguish between [leading](https://github.com/dtolnay/syn/blob/2.0.87/src/fixup.rs#L293) and [trailing](https://github.com/dtolnay/syn/blob/2.0.87/src/fixup.rs#L309) precedence, taking into account an expression's context such as what token follows it (for various syntactic bail-outs in Rust's grammar, like ambiguities around break-with-value) and how it relates to operators from the surrounding syntax tree.
- There are no hardcoded mysterious integer quantities like rustc's `PREC_CLOSURE = -40`. All precedence comparisons are performed via PartialOrd on a C-like enum.
This PR is just a first step in these changes. As you can tell from Syn, I definitely think there is value in having a dedicated type to represent precedence, instead of what `order()` is doing with `i8`. But that is a whole separate adventure because rustc_ast doesn't even agree consistently on `i8` being the type for precedence order; `AssocOp::precedence` instead uses `usize` and there are casts in both directions. It is likely that a type called `ExprPrecedence` will re-appear, but it will look substantially different from the one that existed before this PR.
Rollup of 9 pull requests
Successful merges:
- #122670 (Fix bug where `option_env!` would return `None` when env var is present but not valid Unicode)
- #131095 (Use environment variables instead of command line arguments for merged doctests)
- #131339 (Expand set_ptr_value / with_metadata_of docs)
- #131652 (Move polarity into `PolyTraitRef` rather than storing it on the side)
- #131675 (Update lint message for ABI not supported)
- #131681 (Fix up-to-date checking for run-make tests)
- #131702 (Suppress import errors for traits that couldve applied for method lookup error)
- #131703 (Resolved python deprecation warning in publish_toolstate.py)
- #131710 (Remove `'apostrophes'` from `rustc_parse_format`)
r? `@ghost`
`@rustbot` modify labels: rollup
Add `&pin (mut|const) T` type position sugar
This adds parser support for `&pin mut T` and `&pin const T` references. These are desugared to `Pin<&mut T>` and `Pin<&T>` in the AST lowering phases.
This PR currently includes #130526 since that one is in the commit queue. Only the most recent commits (bd450027eb4a94b814a7dd9c0fa29102e6361149 and following) are new.
Tracking:
- #130494
r? `@compiler-errors`
Retire the `unnamed_fields` feature for now
`#![feature(unnamed_fields)]` was implemented in part in #115131 and #115367, however work on that feature has (afaict) stalled and in the mean time there have been some concerns raised (e.g.[^1][^2]) about whether `unnamed_fields` is worthwhile to have in the language, especially in its current desugaring. Because it represents a compiler implementation burden including a new kind of anonymous ADT and additional complication to field selection, and is quite prone to bugs today, I'm choosing to remove the feature.
However, since I'm not one to really write a bunch of words, I'm specifically *not* going to de-RFC this feature. This PR essentially *rolls back* the state of this feature to "RFC accepted but not yet implemented"; however if anyone wants to formally unapprove the RFC from the t-lang side, then please be my guest. I'm just not totally willing to summarize the various language-facing reasons for why this feature is or is not worthwhile, since I'm coming from the compiler side mostly.
Fixes#117942Fixes#121161Fixes#121263Fixes#121299Fixes#121722Fixes#121799Fixes#126969Fixes#131041
Tracking:
* https://github.com/rust-lang/rust/issues/49804
[^1]: https://rust-lang.zulipchat.com/#narrow/stream/213817-t-lang/topic/Unnamed.20struct.2Funion.20fields
[^2]: https://github.com/rust-lang/rust/issues/49804#issuecomment-1972619108
Parenthesize break values containing leading label
The AST pretty printer previously produced invalid syntax in the case of `break` expressions with a value that begins with a loop or block label.
```rust
macro_rules! expr {
($e:expr) => {
$e
};
}
fn main() {
loop {
break expr!('a: loop { break 'a 1; } + 1);
};
}
```
`rustc -Zunpretty=expanded main.rs `:
```console
#![feature(prelude_import)]
#![no_std]
#[prelude_import]
use ::std::prelude::rust_2015::*;
#[macro_use]
extern crate std;
macro_rules! expr { ($e:expr) => { $e }; }
fn main() { loop { break 'a: loop { break 'a 1; } + 1; }; }
```
The expanded code is not valid Rust syntax. Printing invalid syntax is bad because it blocks `cargo expand` from being able to format the output as Rust syntax using rustfmt.
```console
error: parentheses are required around this expression to avoid confusion with a labeled break expression
--> <anon>:9:26
|
9 | fn main() { loop { break 'a: loop { break 'a 1; } + 1; }; }
| ^^^^^^^^^^^^^^^^^^^^^^^^
|
help: wrap the expression in parentheses
|
9 | fn main() { loop { break ('a: loop { break 'a 1; }) + 1; }; }
| + +
```
This PR updates the AST pretty-printer to insert parentheses around the value of a `break` expression as required to avoid this edge case.
delegation: Implement glob delegation
Support delegating to all trait methods in one go.
Overriding globs with explicit definitions is also supported.
The implementation is generally based on the design from https://github.com/rust-lang/rfcs/pull/3530#issuecomment-2020869823, but unlike with list delegation in https://github.com/rust-lang/rust/pull/123413 we cannot expand glob delegation eagerly.
We have to enqueue it into the queue of unexpanded macros (most other macros are processed this way too), and then a glob delegation waits in that queue until its trait path is resolved, and enough code expands to generate the identifier list produced from the glob.
Glob delegation is only allowed in impls, and can only point to traits.
Supporting it in other places gives very little practical benefit, but significantly raises the implementation complexity.
Part of https://github.com/rust-lang/rust/issues/118212.
We already do this for a number of crates, e.g. `rustc_middle`,
`rustc_span`, `rustc_metadata`, `rustc_span`, `rustc_errors`.
For the ones we don't, in many cases the attributes are a mess.
- There is no consistency about order of attribute kinds (e.g.
`allow`/`deny`/`feature`).
- Within attribute kind groups (e.g. the `feature` attributes),
sometimes the order is alphabetical, and sometimes there is no
particular order.
- Sometimes the attributes of a particular kind aren't even grouped
all together, e.g. there might be a `feature`, then an `allow`, then
another `feature`.
This commit extends the existing sorting to all compiler crates,
increasing consistency. If any new attribute line is added there is now
only one place it can go -- no need for arbitrary decisions.
Exceptions:
- `rustc_log`, `rustc_next_trait_solver` and `rustc_type_ir_macros`,
because they have no crate attributes.
- `rustc_codegen_gcc`, because it's quasi-external to rustc (e.g. it's
ignored in `rustfmt.toml`).
Print `token::Interpolated` with token stream pretty printing.
This is a step towards removing `token::Interpolated` (#124141). It unavoidably changes the output of the `stringify!` macro, generally for the better.
r? `@petrochenkov`
Parse unsafe attributes
Initial parse implementation for #123757
This is the initial work to parse unsafe attributes, which is represented as an extra `unsafety` field in `MetaItem` and `AttrItem`. There's two areas in the code where it appears that parsing is done manually and not using the parser stuff, and I'm not sure how I'm supposed to thread the change there.
Instead of using AST pretty printing.
This is a step towards removing `token::Interpolated`, which will
eventually (in #124141) be replaced with a token stream within invisible
delimiters.
This changes (improves) the output of the `stringify!` macro in some
cases. This is allowed. As the `stringify!` docs say: "Note that the
expanded results of the input tokens may change in the future. You
should be careful if you rely on the output."
Test changes:
- tests/ui/macros/stringify.rs: this used to test both token stream
pretty printing and AST pretty printing via different ways of invoking
of `stringify!` (i.e. `$expr` vs `$tt`). But those two different
invocations now give the same result, which is a nice consistency
improvement. This removes the need for all the `c2*` macros. The AST
pretty printer now has more thorough testing thanks to #125236.
- tests/ui/proc-macro/*: minor improvements where small differences
between `INPUT (DISPLAY)` output and `DEEP-RE-COLLECTED (DISPLAY)`
output disappear.
