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path: root/compiler/rustc_parse/src/parser/pat.rs
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2025-09-15Detect attempt to use var-args in closureEsteban Küber-8/+19
``` error: unexpected `...` --> $DIR/varargs-in-closure-isnt-supported.rs:5:20 | LL | let mut lol = |...| (); | ^^^ not a valid pattern | = note: C-variadic type `...` is not allowed here ```
2025-08-25add span to struct pattern rest (..)Valdemar Erk-1/+1
2025-08-14Rollup merge of #137872 - estebank:extra-vert, r=compiler-errorsJakub Beránek-8/+10
Include whitespace in "remove |" suggestion and make it hidden Tweak error rendering of patterns with an extra `|` on either end. Built on #137409. Only last commit is relevant. ? ``@compiler-errors``
2025-08-09remove `P`Deadbeef-20/+19
2025-08-04Include whitespace in "remove `|`" suggestion and make it hiddenEsteban Küber-8/+10
2025-06-12avoid `&mut P<T>` in `visit_expr` etc methodsDeadbeef-1/+1
2025-05-27Reduce `P<T>` to a typedef of `Box<T>`.Nicholas Nethercote-1/+1
Keep the `P` constructor function for now, to minimize immediate churn. All the `into_inner` calls are removed, which is nice.
2025-04-21Remove `token::{Open,Close}Delim`.Nicholas Nethercote-25/+24
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 { ```
2025-04-02Impl `Copy` for `Token` and `TokenKind`.Nicholas Nethercote-3/+3
2025-04-02Remove `NtExpr` and `NtLiteral`.Nicholas Nethercote-1/+1
Notes about tests: - tests/ui/rfcs/rfc-2294-if-let-guard/feature-gate.rs: some messages are now duplicated due to repeated parsing. - tests/ui/rfcs/rfc-2497-if-let-chains/disallowed-positions.rs: ditto. - `tests/ui/proc-macro/macro-rules-derive-cfg.rs`: the diff looks large but the only difference is the insertion of a single invisible-delimited group around a metavar. - `tests/ui/attributes/nonterminal-expansion.rs`: a slight span degradation, somehow related to the recent massive attr parsing rewrite (#135726). I couldn't work out exactly what is going wrong, but I don't think it's worth holding things up for a single slightly suboptimal error message.
2025-03-21remove `feature(inline_const_pat)`lcnr-9/+0
2025-03-03Rename `ast::TokenKind::Not` as `ast::TokenKind::Bang`.Nicholas Nethercote-3/+3
For consistency with `rustc_lexer::TokenKind::Bang`, and because other `ast::TokenKind` variants generally have syntactic names instead of semantic names (e.g. `Star` and `DotDot` instead of `Mul` and `Range`).
2025-03-03Replace `ast::TokenKind::BinOp{,Eq}` and remove `BinOpToken`.Nicholas Nethercote-4/+8
`BinOpToken` is badly named, because it only covers the assignable binary ops and excludes comparisons and `&&`/`||`. Its use in `ast::TokenKind` does allow a small amount of code sharing, but it's a clumsy factoring. This commit removes `ast::TokenKind::BinOp{,Eq}`, replacing each one with 10 individual variants. This makes `ast::TokenKind` more similar to `rustc_lexer::TokenKind`, which has individual variants for all operators. Although the number of lines of code increases, the number of chars decreases due to the frequent use of shorter names like `token::Plus` instead of `token::BinOp(BinOpToken::Plus)`.
2025-02-28Remove `NtPat`.Nicholas Nethercote-7/+30
The one notable test change is `tests/ui/macros/trace_faulty_macros.rs`. This commit removes the complicated `Interpolated` handling in `expected_expression_found` that results in a longer error message. But I think the new, shorter message is actually an improvement. The original complaint was in #71039, when the error message started with "error: expected expression, found `1 + 1`". That was confusing because `1 + 1` is an expression. Other than that, the reporter said "the whole error message is not too bad if you ignore the first line". Subsequently, extra complexity and wording was added to the error message. But I don't think the extra wording actually helps all that much. In particular, it still says of the `1+1` that "this is expected to be expression". This repeats the problem from the original complaint! This commit removes the extra complexity, reverting to a simpler error message. This is primarily because the traversal is a pain without `Interpolated` tokens. Nonetheless, I think the error message is *improved*. It now starts with "expected expression, found `pat` metavariable", which is much clearer and the real problem. It also doesn't say anything specific about `1+1`, which is good, because the `1+1` isn't really relevant to the error -- it's the `$e:pat` that's important.
2025-02-03Do not allow attributes on struct field rest patternsJack Rickard-11/+11
This removes support for attributes on struct field rest patterns (the `..`) from the parser. Previously they were being parsed but dropped from the AST, so didn't work and were deleted by rustfmt.
2025-01-08Rename PatKind::Lit to ExprOli Scherer-6/+6
2024-12-19Speed up `Parser::expected_token_types`.Nicholas Nethercote-38/+39
The parser pushes a `TokenType` to `Parser::expected_token_types` on every call to the various `check`/`eat` methods, and clears it on every call to `bump`. Some of those `TokenType` values are full tokens that require cloning and dropping. This is a *lot* of work for something that is only used in error messages and it accounts for a significant fraction of parsing execution time. This commit overhauls `TokenType` so that `Parser::expected_token_types` can be implemented as a bitset. This requires changing `TokenType` to a C-style parameterless enum, and adding `TokenTypeSet` which uses a `u128` for the bits. (The new `TokenType` has 105 variants.) The new types `ExpTokenPair` and `ExpKeywordPair` are now arguments to the `check`/`eat` methods. This is for maximum speed. The elements in the pairs are always statically known; e.g. a `token::BinOp(token::Star)` is always paired with a `TokenType::Star`. So we now compute `TokenType`s in advance and pass them in to `check`/`eat` rather than the current approach of constructing them on insertion into `expected_token_types`. Values of these pair types can be produced by the new `exp!` macro, which is used at every `check`/`eat` call site. The macro is for convenience, allowing any pair to be generated from a single identifier. The ident/keyword filtering in `expected_one_of_not_found` is no longer necessary. It was there to account for some sloppiness in `TokenKind`/`TokenType` comparisons. The existing `TokenType` is moved to a new file `token_type.rs`, and all its new infrastructure is added to that file. There is more boilerplate code than I would like, but I can't see how to make it shorter.
2024-12-18Auto merge of #134443 - joshtriplett:use-field-init-shorthand, ↵bors-1/+1
r=lqd,tgross35,nnethercote Use field init shorthand where possible Field init shorthand allows writing initializers like `tcx: tcx` as `tcx`. The compiler already uses it extensively. Fix the last few places where it isn't yet used. EDIT: this PR also updates `rustfmt.toml` to set `use_field_init_shorthand = true`.
2024-12-18Re-export more `rustc_span::symbol` things from `rustc_span`.Nicholas Nethercote-2/+1
`rustc_span::symbol` defines some things that are re-exported from `rustc_span`, such as `Symbol` and `sym`. But it doesn't re-export some closely related things such as `Ident` and `kw`. So you can do `use rustc_span::{Symbol, sym}` but you have to do `use rustc_span::symbol::{Ident, kw}`, which is inconsistent for no good reason. This commit re-exports `Ident`, `kw`, and `MacroRulesNormalizedIdent`, and changes many `rustc_span::symbol::` qualifiers in `compiler/` to `rustc_span::`. This is a 200+ net line of code reduction, mostly because many files with two `use rustc_span` items can be reduced to one.
2024-12-17Use field init shorthand where possibleJosh Triplett-1/+1
Field init shorthand allows writing initializers like `tcx: tcx` as `tcx`. The compiler already uses it extensively. Fix the last few places where it isn't yet used.
2024-12-13Keep track of patterns that could have introduced a binding, but didn'tEsteban Küber-2/+2
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.
2024-12-08Rollup merge of #133424 - Nadrieril:guard-patterns-parsing, r=fee1-deadMatthias Krüger-14/+40
Parse guard patterns This implements the parsing of [RFC3637 Guard Patterns](https://rust-lang.github.io/rfcs/3637-guard-patterns.html) (see also [tracking issue](https://github.com/rust-lang/rust/issues/129967)). This PR is extracted from https://github.com/rust-lang/rust/pull/129996 with minor modifications. cc `@max-niederman`
2024-11-30Eliminate magic numbers from expression precedenceDavid Tolnay-11/+5
2024-11-30Eliminate precedence arithmetic from rustc_parseDavid Tolnay-2/+5
2024-11-28Trim extra space in 'repeated `mut`' diagnosticclubby789-1/+3
2024-11-26Rollup merge of #133140 - dtolnay:precedence, r=fmeaseMichael Goulet-7/+10
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.
2024-11-24parse guard patternsNadrieril-7/+32
Co-authored-by: Max Niederman <max@maxniederman.com>
2024-11-24refactor pat parser method names/doc-comments to agree with RFC 3637Max Niederman-14/+15
2024-11-17Inline ExprPrecedence::order into Expr::precedenceDavid Tolnay-7/+10
2024-11-15Trim whitespace in RemoveLet primary spanTyrone Wu-1/+1
Separate `RemoveLet` span into primary span for `let` and removal suggestion span for `let `, so that primary span does not include whitespace. Fixes: #133031 Signed-off-by: Tyrone Wu <wudevelops@gmail.com>
2024-11-13Trim extra space when suggesting removing bad `let`clubby789-1/+3
2024-10-02Rollup merge of #130725 - GrigorenkoPV:@-in-struct-patterns, r=NadrierilJubilee-13/+41
Parser: better error messages for `@` in struct patterns
2024-09-23Parser: better error messages for `@` in struct patternsPavel Grigorenko-13/+41
2024-09-22Reformat using the new identifier sorting from rustfmtMichael Goulet-4/+4
2024-09-18Add suggestions for expressions in patternsLieselotte-9/+218
2024-09-18Recover more expressions in patternsLieselotte-57/+86
2024-09-11Also fix if in elseMichael Goulet-15/+13
2024-09-06Add initial support for raw lifetimesMichael Goulet-3/+3
2024-09-02chore: Fix typos in 'compiler' (batch 2)Alexander Cyon-1/+1
2024-08-26Don't make pattern nonterminals match statement nonterminalsMichael Goulet-1/+5
2024-08-21Use bool in favor of Option<()> for diagnosticsMichael Goulet-1/+1
2024-08-16Overhaul token collection.Nicholas Nethercote-17/+16
This commit does the following. - Renames `collect_tokens_trailing_token` as `collect_tokens`, because (a) it's annoying long, and (b) the `_trailing_token` bit is less accurate now that its types have changed. - In `collect_tokens`, adds a `Option<CollectPos>` argument and a `UsePreAttrPos` in the return type of `f`. These are used in `parse_expr_force_collect` (for vanilla expressions) and in `parse_stmt_without_recovery` (for two different cases of expression statements). Together these ensure are enough to fix all the problems with token collection and assoc expressions. The changes to the `stringify.rs` test demonstrate some of these. - Adds a new test. The code in this test was causing an assertion failure prior to this commit, due to an invalid `NodeRange`. The extra complexity is annoying, but necessary to fix the existing problems.
2024-08-16Convert a bool to `Trailing`.Nicholas Nethercote-1/+1
This pre-existing type is suitable for use with the return value of the `f` parameter in `collect_tokens_trailing_token`. The more descriptive name will be useful because the next commit will add another boolean value to the return value of `f`.
2024-08-14Use `impl PartialEq<TokenKind> for Token` more.Nicholas Nethercote-10/+10
This lets us compare a `Token` with a `TokenKind`. It's used a lot, but can be used even more, avoiding the need for some `.kind` uses.
2024-07-31Remove `LhsExpr`.Nicholas Nethercote-3/+4
`parse_expr_assoc_with` has an awkward structure -- sometimes the lhs is already parsed. This commit splits the post-lhs part into a new method `parse_expr_assoc_rest_with`, which makes everything shorter and simpler.
2024-07-29Reformat `use` declarations.Nicholas Nethercote-14/+15
The previous commit updated `rustfmt.toml` appropriately. This commit is the outcome of running `x fmt --all` with the new formatting options.
2024-07-22Always pass the visitor as the first argument to walk* functionsOli Scherer-1/+1
2024-07-22Sync `mut_visit` function names with immut `visit` ones (s/noop_visit/walk/)Oli Scherer-2/+2
2024-07-18Remove `TrailingToken`.Nicholas Nethercote-4/+3
It's used in `Parser::collect_tokens_trailing_token` to decide whether to capture a trailing token. But the callers actually know whether to capture a trailing token, so it's simpler for them to just pass in a bool. Also, the `TrailingToken::Gt` case was weird, because it didn't result in a trailing token being captured. It could have been subsumed by the `TrailingToken::MaybeComma` case, and it effectively is in the new code.
2024-07-17Rollup merge of #127806 - nnethercote:parser-improvements, r=spastorinoTrevor Gross-1/+1
Some parser improvements I was looking closely at attribute handling in the parser while debugging some issues relating to #124141, and found a few small improvements. ``@spastorino``