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path: root/compiler/rustc_expand/src/mbe/diagnostics.rs
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2025-08-14mbe: Handle applying `macro_rules` derivesJosh Triplett-7/+17
Add infrastructure to apply a derive macro to arguments, consuming and returning a `TokenTree` only. Handle `SyntaxExtensionKind::MacroRules` when expanding a derive, if the macro's kinds support derive. Add tests covering various cases of `macro_rules` derives. Note that due to a pre-existing FIXME in `expand.rs`, derives are re-queued and some errors get emitted twice. Duplicate diagnostic suppression makes them not visible, but the FIXME should still get fixed.
2025-08-12Detect and report macro kind mismatches early, and more preciselyJosh Triplett-12/+0
This eliminates the case in `failed_to_match_macro` to check for a function-like invocation of a macro with no function-like rules. Instead, macro kind mismatches now result in an unresolved macro, and we detect this case in `unresolved_macro_suggestions`, which now carefully distinguishes between a kind mismatch and other errors. This also handles cases of forward-referenced attributes and cyclic attributes. Expand test coverage to include all of these cases.
2025-08-08mbe: Handle applying attribute rules with pathsJosh Triplett-11/+19
Add infrastructure to apply an attribute macro given argument tokens and body tokens. Teach the resolver to consider `macro_rules` macros when looking for an attribute via a path. This does not yet handle local `macro_rules` attributes.
2025-08-08mbe: Emit an error if a macro call has no function-like rulesJosh Triplett-3/+21
Add a FIXME for moving this error earlier.
2025-08-08mbe: Parse macro attribute rulesJosh Triplett-1/+2
This handles various kinds of errors, but does not allow applying the attributes yet. This adds the feature gate `macro_attr`.
2025-07-05mbe: Defer checks for `compile_error!` until reporting an unused macro ruleJosh Triplett-5/+5
The MBE parser checks rules at initial parse time to see if their RHS has `compile_error!` in it, and returns a list of rule indexes and LHS spans that don't map to `compile_error!`, for use in unused macro rule checking. Instead, have the unused macro rule reporting ask the macro for the rule to report, and let the macro check at that time. That avoids checking rules unless they're unused. In the process, refactor the data structure used to store macro rules, to group the LHS and RHS (and LHS span) of each rule together, and refactor the unused rule tracking to only track rule indexes. This ends up being a net simplification, and reduction in code size.
2025-06-26Rewrite `macro_rules!` parser to not use the MBE engine itselfJosh Triplett-34/+2
The `macro_rules!` parser was written to match the series of rules using the macros-by-example (MBE) engine and a hand-written equivalent of the left-hand side of a MBE macro. This was complex to read, difficult to extend, and produced confusing error messages. Because it was using the MBE engine, any parse failure would be reported as if some macro was being applied to the `macro_rules!` invocation itself; for instance, errors would talk about "macro invocation", "macro arguments", and "macro call", when they were actually about the macro *definition*. And in practice, the `macro_rules!` parser only used the MBE engine to extract the left-hand side and right-hand side of each rule as a token tree, and then parsed the rest using a separate parser. Rewrite it to parse the series of rules using a simple loop, instead. This makes it more extensible in the future, and improves error messages. For instance, omitting a semicolon between rules will result in "expected `;`" and "unexpected token", rather than the confusing "no rules expected this token in macro call". This work was greatly aided by pair programming with Vincenzo Palazzo and Eric Holk.
2025-06-24mbe: Clean up code with non-optional `NonterminalKind`Trevor Gross-0/+1
Since [1], the fragment specifier is unconditionally required in all editions. This means `NonTerminalKind` no longer needs to be optional, as we can reject this code during the expansion of `macro_rules!` rather than handling it throughout the code. Do this cleanup here. [1]: https://github.com/rust-lang/rust/pull/128425
2025-04-21Remove `token::{Open,Close}Delim`.Nicholas Nethercote-3/+3
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-1/+1
2025-04-02Remove `NtBlock`, `Nonterminal`, and `TokenKind::Interpolated`.Nicholas Nethercote-3/+1
`NtBlock` is the last remaining variant of `Nonterminal`, so once it is gone then `Nonterminal` can be removed as well.
2025-01-19Run `clippy --fix` for `unnecessary_map_or` lintYotam Ofek-1/+1
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.
2024-11-21Prepare for invisible delimiters.Nicholas Nethercote-2/+4
Current places where `Interpolated` is used are going to change to instead use invisible delimiters. This prepares for that. - It adds invisible delimiter cases to the `can_begin_*`/`may_be_*` methods and the `failed_to_match_macro` that are equivalent to the existing `Interpolated` cases. - It adds panics/asserts in some places where invisible delimiters should never occur. - In `Parser::parse_struct_fields` it excludes an ident + invisible delimiter from special consideration in an error message, because that's quite different to an ident + paren/brace/bracket.
2024-10-28Tweak more warnings.Nicholas Nethercote-10/+3
Much like the previous commit. I think the removal of "the token" in each message is fine here. There are many more error messages that mention tokens without saying "the token" than those that do say it.
2024-09-22Reformat using the new identifier sorting from rustfmtMichael Goulet-3/+3
2024-08-27Add `warn(unreachable_pub)` to `rustc_expand`.Nicholas Nethercote-3/+4
Plus a tiny bit of reformatting.
2024-08-07refactor(rustc_expand::mbe): Don't require full ExtCtxt when not necessaryFelix Rath-27/+24
2024-07-29Reformat `use` declarations.Nicholas Nethercote-7/+7
The previous commit updated `rustfmt.toml` appropriately. This commit is the outcome of running `x fmt --all` with the new formatting options.
2024-07-02Shrink parser positions from `usize` to `u32`.Nicholas Nethercote-6/+6
The number of source code bytes can't exceed a `u32`'s range, so a token position also can't. This reduces the size of `Parser` and `LazyAttrTokenStreamImpl` by eight bytes each.
2024-06-18Remove redundant argument from `subdiagnostic` methodOli Scherer-10/+5
2024-06-18Use a dedicated type instead of a reference for the diagnostic contextOli Scherer-2/+7
This paves the way for tracking more state (e.g. error tainting) in the diagnostic context handle
2024-05-18Improve error message: missing `;` in macro_rulesr0cky-7/+33
2024-05-13Remove a `Span` from `TokenKind::Interpolated`.Nicholas Nethercote-6/+0
This span records the declaration of the metavariable in the LHS of the macro. It's used in a couple of error messages. Unfortunately, it gets in the way of the long-term goal of removing `TokenKind::Interpolated`. So this commit removes it, which degrades a couple of (obscure) error messages but makes things simpler and enables the next commit.
2024-05-03Fix some comment formatting.Nicholas Nethercote-1/+2
2024-04-30Remove `extern crate tracing` from numerous crates.Nicholas Nethercote-0/+1
2024-04-29Remove `extern crate rustc_macros` from numerous crates.Nicholas Nethercote-0/+1
2024-03-05Rename `DiagnosticMessage` as `DiagMessage`.Nicholas Nethercote-3/+3
2024-03-05Rename all `ParseSess` variables/fields/lifetimes as `psess`.Nicholas Nethercote-7/+7
Existing names for values of this type are `sess`, `parse_sess`, `parse_session`, and `ps`. `sess` is particularly annoying because that's also used for `Session` values, which are often co-located, and it can be difficult to know which type a value named `sess` refers to. (That annoyance is the main motivation for this change.) `psess` is nice and short, which is good for a name used this much. The commit also renames some `parse_sess_created` values as `psess_created`.
2024-02-28Rename `DiagnosticBuilder` as `Diag`.Nicholas Nethercote-13/+4
Much better! Note that this involves renaming (and updating the value of) `DIAGNOSTIC_BUILDER` in clippy.
2024-02-25Add `ErrorGuaranteed` to `ast::ExprKind::Err`Lieselotte-9/+9
2024-02-19Prefer `DiagnosticBuilder` over `Diagnostic` in diagnostic modifiers.Nicholas Nethercote-3/+7
There are lots of functions that modify a diagnostic. This can be via a `&mut Diagnostic` or a `&mut DiagnosticBuilder`, because the latter type wraps the former and impls `DerefMut`. This commit converts all the `&mut Diagnostic` occurrences to `&mut DiagnosticBuilder`. This is a step towards greatly simplifying `Diagnostic`. Some of the relevant function are made generic, because they deal with both errors and warnings. No function bodies are changed, because all the modifier methods are available on both `Diagnostic` and `DiagnosticBuilder`.
2024-02-17Rollup merge of #121085 - davidtwco:always-eager-diagnostics, r=nnethercoteMatthias Krüger-5/+10
errors: only eagerly translate subdiagnostics Subdiagnostics don't need to be lazily translated, they can always be eagerly translated. Eager translation is slightly more complex as we need to have a `DiagCtxt` available to perform the translation, which involves slightly more threading of that context. This slight increase in complexity should enable later simplifications - like passing `DiagCtxt` into `AddToDiagnostic` and moving Fluent messages into the diagnostic structs rather than having them in separate files (working on that was what led to this change). r? ```@nnethercote```
2024-02-15errors: only eagerly translate subdiagnosticsDavid Wood-5/+10
Subdiagnostics don't need to be lazily translated, they can always be eagerly translated. Eager translation is slightly more complex as we need to have a `DiagCtxt` available to perform the translation, which involves slightly more threading of that context. This slight increase in complexity should enable later simplifications - like passing `DiagCtxt` into `AddToDiagnostic` and moving Fluent messages into the diagnostic structs rather than having them in separate files (working on that was what led to this change). Signed-off-by: David Wood <david@davidtw.co>
2024-02-14Use fewer delayed bugs.Nicholas Nethercote-4/+4
For some cases where it's clear that an error has already occurred, e.g.: - there's a comment stating exactly that, or - things like HIR lowering, where we are lowering an error kind The commit also tweaks some comments around delayed bug sites.
2024-01-10Shorten some error invocations.Nicholas Nethercote-1/+1
- `struct_foo` + `emit` -> `foo` - `create_foo` + `emit` -> `emit_foo` I have made recent commits in other PRs that have removed some of these shortcuts for combinations with few uses, e.g. `struct_span_err_with_code`. But for the remaining combinations that have high levels of use, we might as well use them wherever possible.
2023-12-24Remove `Session` methods that duplicate `DiagCtxt` methods.Nicholas Nethercote-2/+5
Also add some `dcx` methods to types that wrap `TyCtxt`, for easier access.
2023-12-24Remove `ExtCtxt` methods that duplicate `DiagCtxt` methods.Nicholas Nethercote-2/+2
2023-12-23Improve some names.Nicholas Nethercote-3/+3
Lots of vectors of messages called `message` or `msg`. This commit pluralizes them. Note that `emit_message_default` and `emit_messages_default` both already existed, and both process a vector, so I renamed the former `emit_messages_default_inner` because it's called by the latter.
2023-12-23Give `DiagnosticBuilder` a default type.Nicholas Nethercote-1/+1
`IntoDiagnostic` defaults to `ErrorGuaranteed`, because errors are the most common diagnostic level. It makes sense to do likewise for the closely-related (and much more widely used) `DiagnosticBuilder` type, letting us write `DiagnosticBuilder<'a, ErrorGuaranteed>` as just `DiagnosticBuilder<'a>`. This cuts over 200 lines of code due to many multi-line things becoming single line things.
2023-12-02Rename `HandlerInner::delay_span_bug` as `HandlerInner::span_delayed_bug`.Nicholas Nethercote-2/+2
Because the corresponding `Level` is `DelayedBug` and `span_delayed_bug` follows the pattern used everywhere else: `span_err`, `span_warning`, etc.
2023-11-16More detail when expecting expression but encountering bad macro argumentEsteban Küber-0/+6
Partially address #71039.
2023-07-30inline format!() args up to and including rustc_middleMatthias Krüger-1/+1
2023-07-12Re-format let-else per rustfmt updateMark Rousskov-1/+2
2023-05-29Use `Cow` in `{D,Subd}iagnosticMessage`.Nicholas Nethercote-5/+5
Each of `{D,Subd}iagnosticMessage::{Str,Eager}` has a comment: ``` // FIXME(davidtwco): can a `Cow<'static, str>` be used here? ``` This commit answers that question in the affirmative. It's not the most compelling change ever, but it might be worth merging. This requires changing the `impl<'a> From<&'a str>` impls to `impl From<&'static str>`, which involves a bunch of knock-on changes that require/result in call sites being a little more precise about exactly what kind of string they use to create errors, and not just `&str`. This will result in fewer unnecessary allocations, though this will not have any notable perf effects given that these are error paths. Note that I was lazy within Clippy, using `to_string` in a few places to preserve the existing string imprecision. I could have used `impl Into<{D,Subd}iagnosticMessage>` in various places as is done in the compiler, but that would have required changes to *many* call sites (mostly changing `&format("...")` to `format!("...")`) which didn't seem worthwhile.
2023-05-16Avoid `&format("...")` calls in error message code.Nicholas Nethercote-2/+2
Error message all end up passing into a function as an `impl Into<{D,Subd}iagnosticMessage>`. If an error message is creatd as `&format("...")` that means we allocate a string (in the `format!` call), then take a reference, and then clone (allocating again) the reference to produce the `{D,Subd}iagnosticMessage`, which is silly. This commit removes the leading `&` from a lot of these cases. This means the original `String` is moved into the `{D,Subd}iagnosticMessage`, avoiding the double allocations. This requires changing some function argument types from `&str` to `String` (when all arguments are `String`) or `impl Into<{D,Subd}iagnosticMessage>` (when some arguments are `String` and some are `&str`).
2023-04-12compiler: print the suggestion only for local macrosLena Milizé-2/+5
And wrap the link in the diagnostic in angle brackets. Signed-off-by: Lena Milizé <me@lvmn.org>
2023-04-12compiler: improve captured metavariables diagnosticLena Milizé-1/+3
Adds a link to the relevant part of The Rust Reference in the eror message, and suggests a possible fix (replacing the fragment specifier with :tt in the macro definition). Fixes typos in the original message. Signed-off-by: Lena Milizé <me@lvmn.org>
2023-03-17Suggest surrounding the macro with `{}` to interpret as a statementMu42-6/+18
2023-03-10Add note when matching token with nonterminalNilstrieb-3/+9
The current error message is _really_ confusing.