rustc_lint/
internal.rs

1//! Some lints that are only useful in the compiler or crates that use compiler internals, such as
2//! Clippy.
3
4use rustc_hir::HirId;
5use rustc_hir::def::Res;
6use rustc_hir::def_id::DefId;
7use rustc_middle::ty::{self, GenericArgsRef, Ty as MiddleTy};
8use rustc_session::{declare_lint_pass, declare_tool_lint};
9use rustc_span::hygiene::{ExpnKind, MacroKind};
10use rustc_span::{Span, sym};
11use tracing::debug;
12use {rustc_ast as ast, rustc_hir as hir};
13
14use crate::lints::{
15    BadOptAccessDiag, DefaultHashTypesDiag, DiagOutOfImpl, LintPassByHand,
16    NonGlobImportTypeIrInherent, QueryInstability, QueryUntracked, SpanUseEqCtxtDiag,
17    SymbolInternStringLiteralDiag, TyQualified, TykindDiag, TykindKind, TypeIrInherentUsage,
18    TypeIrTraitUsage, UntranslatableDiag,
19};
20use crate::{EarlyContext, EarlyLintPass, LateContext, LateLintPass, LintContext};
21
22declare_tool_lint! {
23    /// The `default_hash_type` lint detects use of [`std::collections::HashMap`] and
24    /// [`std::collections::HashSet`], suggesting the use of `FxHashMap`/`FxHashSet`.
25    ///
26    /// This can help as `FxHasher` can perform better than the default hasher. DOS protection is
27    /// not required as input is assumed to be trusted.
28    pub rustc::DEFAULT_HASH_TYPES,
29    Allow,
30    "forbid HashMap and HashSet and suggest the FxHash* variants",
31    report_in_external_macro: true
32}
33
34declare_lint_pass!(DefaultHashTypes => [DEFAULT_HASH_TYPES]);
35
36impl LateLintPass<'_> for DefaultHashTypes {
37    fn check_path(&mut self, cx: &LateContext<'_>, path: &hir::Path<'_>, hir_id: HirId) {
38        let Res::Def(rustc_hir::def::DefKind::Struct, def_id) = path.res else { return };
39        if matches!(
40            cx.tcx.hir_node(hir_id),
41            hir::Node::Item(hir::Item { kind: hir::ItemKind::Use(..), .. })
42        ) {
43            // Don't lint imports, only actual usages.
44            return;
45        }
46        let preferred = match cx.tcx.get_diagnostic_name(def_id) {
47            Some(sym::HashMap) => "FxHashMap",
48            Some(sym::HashSet) => "FxHashSet",
49            _ => return,
50        };
51        cx.emit_span_lint(
52            DEFAULT_HASH_TYPES,
53            path.span,
54            DefaultHashTypesDiag { preferred, used: cx.tcx.item_name(def_id) },
55        );
56    }
57}
58
59/// Helper function for lints that check for expressions with calls and use typeck results to
60/// get the `DefId` and `GenericArgsRef` of the function.
61fn typeck_results_of_method_fn<'tcx>(
62    cx: &LateContext<'tcx>,
63    expr: &hir::Expr<'_>,
64) -> Option<(Span, DefId, ty::GenericArgsRef<'tcx>)> {
65    match expr.kind {
66        hir::ExprKind::MethodCall(segment, ..)
67            if let Some(def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id) =>
68        {
69            Some((segment.ident.span, def_id, cx.typeck_results().node_args(expr.hir_id)))
70        }
71        _ => match cx.typeck_results().node_type(expr.hir_id).kind() {
72            &ty::FnDef(def_id, args) => Some((expr.span, def_id, args)),
73            _ => None,
74        },
75    }
76}
77
78declare_tool_lint! {
79    /// The `potential_query_instability` lint detects use of methods which can lead to
80    /// potential query instability, such as iterating over a `HashMap`.
81    ///
82    /// Due to the [incremental compilation](https://rustc-dev-guide.rust-lang.org/queries/incremental-compilation.html) model,
83    /// queries must return deterministic, stable results. `HashMap` iteration order can change
84    /// between compilations, and will introduce instability if query results expose the order.
85    pub rustc::POTENTIAL_QUERY_INSTABILITY,
86    Allow,
87    "require explicit opt-in when using potentially unstable methods or functions",
88    report_in_external_macro: true
89}
90
91declare_tool_lint! {
92    /// The `untracked_query_information` lint detects use of methods which leak information not
93    /// tracked by the query system, such as whether a `Steal<T>` value has already been stolen. In
94    /// order not to break incremental compilation, such methods must be used very carefully or not
95    /// at all.
96    pub rustc::UNTRACKED_QUERY_INFORMATION,
97    Allow,
98    "require explicit opt-in when accessing information not tracked by the query system",
99    report_in_external_macro: true
100}
101
102declare_lint_pass!(QueryStability => [POTENTIAL_QUERY_INSTABILITY, UNTRACKED_QUERY_INFORMATION]);
103
104impl LateLintPass<'_> for QueryStability {
105    fn check_expr(&mut self, cx: &LateContext<'_>, expr: &hir::Expr<'_>) {
106        let Some((span, def_id, args)) = typeck_results_of_method_fn(cx, expr) else { return };
107        if let Ok(Some(instance)) = ty::Instance::try_resolve(cx.tcx, cx.typing_env(), def_id, args)
108        {
109            let def_id = instance.def_id();
110            if cx.tcx.has_attr(def_id, sym::rustc_lint_query_instability) {
111                cx.emit_span_lint(
112                    POTENTIAL_QUERY_INSTABILITY,
113                    span,
114                    QueryInstability { query: cx.tcx.item_name(def_id) },
115                );
116            }
117            if cx.tcx.has_attr(def_id, sym::rustc_lint_untracked_query_information) {
118                cx.emit_span_lint(
119                    UNTRACKED_QUERY_INFORMATION,
120                    span,
121                    QueryUntracked { method: cx.tcx.item_name(def_id) },
122                );
123            }
124        }
125    }
126}
127
128declare_tool_lint! {
129    /// The `usage_of_ty_tykind` lint detects usages of `ty::TyKind::<kind>`,
130    /// where `ty::<kind>` would suffice.
131    pub rustc::USAGE_OF_TY_TYKIND,
132    Allow,
133    "usage of `ty::TyKind` outside of the `ty::sty` module",
134    report_in_external_macro: true
135}
136
137declare_tool_lint! {
138    /// The `usage_of_qualified_ty` lint detects usages of `ty::TyKind`,
139    /// where `Ty` should be used instead.
140    pub rustc::USAGE_OF_QUALIFIED_TY,
141    Allow,
142    "using `ty::{Ty,TyCtxt}` instead of importing it",
143    report_in_external_macro: true
144}
145
146declare_lint_pass!(TyTyKind => [
147    USAGE_OF_TY_TYKIND,
148    USAGE_OF_QUALIFIED_TY,
149]);
150
151impl<'tcx> LateLintPass<'tcx> for TyTyKind {
152    fn check_path(
153        &mut self,
154        cx: &LateContext<'tcx>,
155        path: &rustc_hir::Path<'tcx>,
156        _: rustc_hir::HirId,
157    ) {
158        if let Some(segment) = path.segments.iter().nth_back(1)
159            && lint_ty_kind_usage(cx, &segment.res)
160        {
161            let span =
162                path.span.with_hi(segment.args.map_or(segment.ident.span, |a| a.span_ext).hi());
163            cx.emit_span_lint(USAGE_OF_TY_TYKIND, path.span, TykindKind { suggestion: span });
164        }
165    }
166
167    fn check_ty(&mut self, cx: &LateContext<'_>, ty: &'tcx hir::Ty<'tcx, hir::AmbigArg>) {
168        match &ty.kind {
169            hir::TyKind::Path(hir::QPath::Resolved(_, path)) => {
170                if lint_ty_kind_usage(cx, &path.res) {
171                    let span = match cx.tcx.parent_hir_node(ty.hir_id) {
172                        hir::Node::PatExpr(hir::PatExpr {
173                            kind: hir::PatExprKind::Path(qpath),
174                            ..
175                        })
176                        | hir::Node::Pat(hir::Pat {
177                            kind:
178                                hir::PatKind::TupleStruct(qpath, ..) | hir::PatKind::Struct(qpath, ..),
179                            ..
180                        })
181                        | hir::Node::Expr(
182                            hir::Expr { kind: hir::ExprKind::Path(qpath), .. }
183                            | &hir::Expr { kind: hir::ExprKind::Struct(qpath, ..), .. },
184                        ) => {
185                            if let hir::QPath::TypeRelative(qpath_ty, ..) = qpath
186                                && qpath_ty.hir_id == ty.hir_id
187                            {
188                                Some(path.span)
189                            } else {
190                                None
191                            }
192                        }
193                        _ => None,
194                    };
195
196                    match span {
197                        Some(span) => {
198                            cx.emit_span_lint(
199                                USAGE_OF_TY_TYKIND,
200                                path.span,
201                                TykindKind { suggestion: span },
202                            );
203                        }
204                        None => cx.emit_span_lint(USAGE_OF_TY_TYKIND, path.span, TykindDiag),
205                    }
206                } else if !ty.span.from_expansion()
207                    && path.segments.len() > 1
208                    && let Some(ty) = is_ty_or_ty_ctxt(cx, path)
209                {
210                    cx.emit_span_lint(
211                        USAGE_OF_QUALIFIED_TY,
212                        path.span,
213                        TyQualified { ty, suggestion: path.span },
214                    );
215                }
216            }
217            _ => {}
218        }
219    }
220}
221
222fn lint_ty_kind_usage(cx: &LateContext<'_>, res: &Res) -> bool {
223    if let Some(did) = res.opt_def_id() {
224        cx.tcx.is_diagnostic_item(sym::TyKind, did) || cx.tcx.is_diagnostic_item(sym::IrTyKind, did)
225    } else {
226        false
227    }
228}
229
230fn is_ty_or_ty_ctxt(cx: &LateContext<'_>, path: &hir::Path<'_>) -> Option<String> {
231    match &path.res {
232        Res::Def(_, def_id) => {
233            if let Some(name @ (sym::Ty | sym::TyCtxt)) = cx.tcx.get_diagnostic_name(*def_id) {
234                return Some(format!("{}{}", name, gen_args(path.segments.last().unwrap())));
235            }
236        }
237        // Only lint on `&Ty` and `&TyCtxt` if it is used outside of a trait.
238        Res::SelfTyAlias { alias_to: did, is_trait_impl: false, .. } => {
239            if let ty::Adt(adt, args) = cx.tcx.type_of(did).instantiate_identity().kind()
240                && let Some(name @ (sym::Ty | sym::TyCtxt)) = cx.tcx.get_diagnostic_name(adt.did())
241            {
242                return Some(format!("{}<{}>", name, args[0]));
243            }
244        }
245        _ => (),
246    }
247
248    None
249}
250
251fn gen_args(segment: &hir::PathSegment<'_>) -> String {
252    if let Some(args) = &segment.args {
253        let lifetimes = args
254            .args
255            .iter()
256            .filter_map(|arg| {
257                if let hir::GenericArg::Lifetime(lt) = arg {
258                    Some(lt.ident.to_string())
259                } else {
260                    None
261                }
262            })
263            .collect::<Vec<_>>();
264
265        if !lifetimes.is_empty() {
266            return format!("<{}>", lifetimes.join(", "));
267        }
268    }
269
270    String::new()
271}
272
273declare_tool_lint! {
274    /// The `non_glob_import_of_type_ir_inherent_item` lint detects
275    /// non-glob imports of module `rustc_type_ir::inherent`.
276    pub rustc::NON_GLOB_IMPORT_OF_TYPE_IR_INHERENT,
277    Allow,
278    "non-glob import of `rustc_type_ir::inherent`",
279    report_in_external_macro: true
280}
281
282declare_tool_lint! {
283    /// The `usage_of_type_ir_inherent` lint detects usage of `rustc_type_ir::inherent`.
284    ///
285    /// This module should only be used within the trait solver.
286    pub rustc::USAGE_OF_TYPE_IR_INHERENT,
287    Allow,
288    "usage `rustc_type_ir::inherent` outside of trait system",
289    report_in_external_macro: true
290}
291
292declare_tool_lint! {
293    /// The `usage_of_type_ir_traits` lint detects usage of `rustc_type_ir::Interner`,
294    /// or `rustc_infer::InferCtxtLike`.
295    ///
296    /// Methods of this trait should only be used within the type system abstraction layer,
297    /// and in the generic next trait solver implementation. Look for an analogously named
298    /// method on `TyCtxt` or `InferCtxt` (respectively).
299    pub rustc::USAGE_OF_TYPE_IR_TRAITS,
300    Allow,
301    "usage `rustc_type_ir`-specific abstraction traits outside of trait system",
302    report_in_external_macro: true
303}
304
305declare_lint_pass!(TypeIr => [NON_GLOB_IMPORT_OF_TYPE_IR_INHERENT, USAGE_OF_TYPE_IR_INHERENT, USAGE_OF_TYPE_IR_TRAITS]);
306
307impl<'tcx> LateLintPass<'tcx> for TypeIr {
308    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'tcx>) {
309        let res_def_id = match expr.kind {
310            hir::ExprKind::Path(hir::QPath::Resolved(_, path)) => path.res.opt_def_id(),
311            hir::ExprKind::Path(hir::QPath::TypeRelative(..)) | hir::ExprKind::MethodCall(..) => {
312                cx.typeck_results().type_dependent_def_id(expr.hir_id)
313            }
314            _ => return,
315        };
316        let Some(res_def_id) = res_def_id else {
317            return;
318        };
319        if let Some(assoc_item) = cx.tcx.opt_associated_item(res_def_id)
320            && let Some(trait_def_id) = assoc_item.trait_container(cx.tcx)
321            && (cx.tcx.is_diagnostic_item(sym::type_ir_interner, trait_def_id)
322                | cx.tcx.is_diagnostic_item(sym::type_ir_infer_ctxt_like, trait_def_id))
323        {
324            cx.emit_span_lint(USAGE_OF_TYPE_IR_TRAITS, expr.span, TypeIrTraitUsage);
325        }
326    }
327
328    fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::Item<'tcx>) {
329        let rustc_hir::ItemKind::Use(path, kind) = item.kind else { return };
330
331        let is_mod_inherent = |def_id| cx.tcx.is_diagnostic_item(sym::type_ir_inherent, def_id);
332
333        // Path segments except for the final.
334        if let Some(seg) =
335            path.segments.iter().find(|seg| seg.res.opt_def_id().is_some_and(is_mod_inherent))
336        {
337            cx.emit_span_lint(USAGE_OF_TYPE_IR_INHERENT, seg.ident.span, TypeIrInherentUsage);
338        }
339        // Final path resolutions, like `use rustc_type_ir::inherent`
340        else if path.res.iter().any(|res| res.opt_def_id().is_some_and(is_mod_inherent)) {
341            cx.emit_span_lint(
342                USAGE_OF_TYPE_IR_INHERENT,
343                path.segments.last().unwrap().ident.span,
344                TypeIrInherentUsage,
345            );
346        }
347
348        let (lo, hi, snippet) = match path.segments {
349            [.., penultimate, segment]
350                if penultimate.res.opt_def_id().is_some_and(is_mod_inherent) =>
351            {
352                (segment.ident.span, item.kind.ident().unwrap().span, "*")
353            }
354            [.., segment]
355                if path.res.iter().flat_map(Res::opt_def_id).any(is_mod_inherent)
356                    && let rustc_hir::UseKind::Single(ident) = kind =>
357            {
358                let (lo, snippet) =
359                    match cx.tcx.sess.source_map().span_to_snippet(path.span).as_deref() {
360                        Ok("self") => (path.span, "*"),
361                        _ => (segment.ident.span.shrink_to_hi(), "::*"),
362                    };
363                (lo, if segment.ident == ident { lo } else { ident.span }, snippet)
364            }
365            _ => return,
366        };
367        cx.emit_span_lint(
368            NON_GLOB_IMPORT_OF_TYPE_IR_INHERENT,
369            path.span,
370            NonGlobImportTypeIrInherent { suggestion: lo.eq_ctxt(hi).then(|| lo.to(hi)), snippet },
371        );
372    }
373}
374
375declare_tool_lint! {
376    /// The `lint_pass_impl_without_macro` detects manual implementations of a lint
377    /// pass, without using [`declare_lint_pass`] or [`impl_lint_pass`].
378    pub rustc::LINT_PASS_IMPL_WITHOUT_MACRO,
379    Allow,
380    "`impl LintPass` without the `declare_lint_pass!` or `impl_lint_pass!` macros"
381}
382
383declare_lint_pass!(LintPassImpl => [LINT_PASS_IMPL_WITHOUT_MACRO]);
384
385impl EarlyLintPass for LintPassImpl {
386    fn check_item(&mut self, cx: &EarlyContext<'_>, item: &ast::Item) {
387        if let ast::ItemKind::Impl(box ast::Impl { of_trait: Some(lint_pass), .. }) = &item.kind {
388            if let Some(last) = lint_pass.path.segments.last() {
389                if last.ident.name == sym::LintPass {
390                    let expn_data = lint_pass.path.span.ctxt().outer_expn_data();
391                    let call_site = expn_data.call_site;
392                    if expn_data.kind != ExpnKind::Macro(MacroKind::Bang, sym::impl_lint_pass)
393                        && call_site.ctxt().outer_expn_data().kind
394                            != ExpnKind::Macro(MacroKind::Bang, sym::declare_lint_pass)
395                    {
396                        cx.emit_span_lint(
397                            LINT_PASS_IMPL_WITHOUT_MACRO,
398                            lint_pass.path.span,
399                            LintPassByHand,
400                        );
401                    }
402                }
403            }
404        }
405    }
406}
407
408declare_tool_lint! {
409    /// The `untranslatable_diagnostic` lint detects messages passed to functions with `impl
410    /// Into<{D,Subd}iagMessage` parameters without using translatable Fluent strings.
411    ///
412    /// More details on translatable diagnostics can be found
413    /// [here](https://rustc-dev-guide.rust-lang.org/diagnostics/translation.html).
414    pub rustc::UNTRANSLATABLE_DIAGNOSTIC,
415    Allow,
416    "prevent creation of diagnostics which cannot be translated",
417    report_in_external_macro: true,
418    @eval_always = true
419}
420
421declare_tool_lint! {
422    /// The `diagnostic_outside_of_impl` lint detects calls to functions annotated with
423    /// `#[rustc_lint_diagnostics]` that are outside an `Diagnostic`, `Subdiagnostic`, or
424    /// `LintDiagnostic` impl (either hand-written or derived).
425    ///
426    /// More details on diagnostics implementations can be found
427    /// [here](https://rustc-dev-guide.rust-lang.org/diagnostics/diagnostic-structs.html).
428    pub rustc::DIAGNOSTIC_OUTSIDE_OF_IMPL,
429    Allow,
430    "prevent diagnostic creation outside of `Diagnostic`/`Subdiagnostic`/`LintDiagnostic` impls",
431    report_in_external_macro: true,
432    @eval_always = true
433}
434
435declare_lint_pass!(Diagnostics => [UNTRANSLATABLE_DIAGNOSTIC, DIAGNOSTIC_OUTSIDE_OF_IMPL]);
436
437impl LateLintPass<'_> for Diagnostics {
438    fn check_expr(&mut self, cx: &LateContext<'_>, expr: &hir::Expr<'_>) {
439        let collect_args_tys_and_spans = |args: &[hir::Expr<'_>], reserve_one_extra: bool| {
440            let mut result = Vec::with_capacity(args.len() + usize::from(reserve_one_extra));
441            result.extend(args.iter().map(|arg| (cx.typeck_results().expr_ty(arg), arg.span)));
442            result
443        };
444        // Only check function calls and method calls.
445        let (span, def_id, fn_gen_args, arg_tys_and_spans) = match expr.kind {
446            hir::ExprKind::Call(callee, args) => {
447                match cx.typeck_results().node_type(callee.hir_id).kind() {
448                    &ty::FnDef(def_id, fn_gen_args) => {
449                        (callee.span, def_id, fn_gen_args, collect_args_tys_and_spans(args, false))
450                    }
451                    _ => return, // occurs for fns passed as args
452                }
453            }
454            hir::ExprKind::MethodCall(_segment, _recv, args, _span) => {
455                let Some((span, def_id, fn_gen_args)) = typeck_results_of_method_fn(cx, expr)
456                else {
457                    return;
458                };
459                let mut args = collect_args_tys_and_spans(args, true);
460                args.insert(0, (cx.tcx.types.self_param, _recv.span)); // dummy inserted for `self`
461                (span, def_id, fn_gen_args, args)
462            }
463            _ => return,
464        };
465
466        Self::diagnostic_outside_of_impl(cx, span, expr.hir_id, def_id, fn_gen_args);
467        Self::untranslatable_diagnostic(cx, def_id, &arg_tys_and_spans);
468    }
469}
470
471impl Diagnostics {
472    // Is the type `{D,Subd}iagMessage`?
473    fn is_diag_message<'cx>(cx: &LateContext<'cx>, ty: MiddleTy<'cx>) -> bool {
474        if let Some(adt_def) = ty.ty_adt_def()
475            && let Some(name) = cx.tcx.get_diagnostic_name(adt_def.did())
476            && matches!(name, sym::DiagMessage | sym::SubdiagMessage)
477        {
478            true
479        } else {
480            false
481        }
482    }
483
484    fn untranslatable_diagnostic<'cx>(
485        cx: &LateContext<'cx>,
486        def_id: DefId,
487        arg_tys_and_spans: &[(MiddleTy<'cx>, Span)],
488    ) {
489        let fn_sig = cx.tcx.fn_sig(def_id).instantiate_identity().skip_binder();
490        let predicates = cx.tcx.predicates_of(def_id).instantiate_identity(cx.tcx).predicates;
491        for (i, &param_ty) in fn_sig.inputs().iter().enumerate() {
492            if let ty::Param(sig_param) = param_ty.kind() {
493                // It is a type parameter. Check if it is `impl Into<{D,Subd}iagMessage>`.
494                for pred in predicates.iter() {
495                    if let Some(trait_pred) = pred.as_trait_clause()
496                        && let trait_ref = trait_pred.skip_binder().trait_ref
497                        && trait_ref.self_ty() == param_ty // correct predicate for the param?
498                        && cx.tcx.is_diagnostic_item(sym::Into, trait_ref.def_id)
499                        && let ty1 = trait_ref.args.type_at(1)
500                        && Self::is_diag_message(cx, ty1)
501                    {
502                        // Calls to methods with an `impl Into<{D,Subd}iagMessage>` parameter must be passed an arg
503                        // with type `{D,Subd}iagMessage` or `impl Into<{D,Subd}iagMessage>`. Otherwise, emit an
504                        // `UNTRANSLATABLE_DIAGNOSTIC` lint.
505                        let (arg_ty, arg_span) = arg_tys_and_spans[i];
506
507                        // Is the arg type `{Sub,D}iagMessage`or `impl Into<{Sub,D}iagMessage>`?
508                        let is_translatable = Self::is_diag_message(cx, arg_ty)
509                            || matches!(arg_ty.kind(), ty::Param(arg_param) if arg_param.name == sig_param.name);
510                        if !is_translatable {
511                            cx.emit_span_lint(
512                                UNTRANSLATABLE_DIAGNOSTIC,
513                                arg_span,
514                                UntranslatableDiag,
515                            );
516                        }
517                    }
518                }
519            }
520        }
521    }
522
523    fn diagnostic_outside_of_impl<'cx>(
524        cx: &LateContext<'cx>,
525        span: Span,
526        current_id: HirId,
527        def_id: DefId,
528        fn_gen_args: GenericArgsRef<'cx>,
529    ) {
530        // Is the callee marked with `#[rustc_lint_diagnostics]`?
531        let Some(inst) =
532            ty::Instance::try_resolve(cx.tcx, cx.typing_env(), def_id, fn_gen_args).ok().flatten()
533        else {
534            return;
535        };
536        let has_attr = cx.tcx.has_attr(inst.def_id(), sym::rustc_lint_diagnostics);
537        if !has_attr {
538            return;
539        };
540
541        for (hir_id, _parent) in cx.tcx.hir_parent_iter(current_id) {
542            if let Some(owner_did) = hir_id.as_owner()
543                && cx.tcx.has_attr(owner_did, sym::rustc_lint_diagnostics)
544            {
545                // The parent method is marked with `#[rustc_lint_diagnostics]`
546                return;
547            }
548        }
549
550        // Calls to `#[rustc_lint_diagnostics]`-marked functions should only occur:
551        // - inside an impl of `Diagnostic`, `Subdiagnostic`, or `LintDiagnostic`, or
552        // - inside a parent function that is itself marked with `#[rustc_lint_diagnostics]`.
553        //
554        // Otherwise, emit a `DIAGNOSTIC_OUTSIDE_OF_IMPL` lint.
555        let mut is_inside_appropriate_impl = false;
556        for (_hir_id, parent) in cx.tcx.hir_parent_iter(current_id) {
557            debug!(?parent);
558            if let hir::Node::Item(hir::Item { kind: hir::ItemKind::Impl(impl_), .. }) = parent
559                && let hir::Impl { of_trait: Some(of_trait), .. } = impl_
560                && let Some(def_id) = of_trait.trait_def_id()
561                && let Some(name) = cx.tcx.get_diagnostic_name(def_id)
562                && matches!(name, sym::Diagnostic | sym::Subdiagnostic | sym::LintDiagnostic)
563            {
564                is_inside_appropriate_impl = true;
565                break;
566            }
567        }
568        debug!(?is_inside_appropriate_impl);
569        if !is_inside_appropriate_impl {
570            cx.emit_span_lint(DIAGNOSTIC_OUTSIDE_OF_IMPL, span, DiagOutOfImpl);
571        }
572    }
573}
574
575declare_tool_lint! {
576    /// The `bad_opt_access` lint detects accessing options by field instead of
577    /// the wrapper function.
578    pub rustc::BAD_OPT_ACCESS,
579    Deny,
580    "prevent using options by field access when there is a wrapper function",
581    report_in_external_macro: true
582}
583
584declare_lint_pass!(BadOptAccess => [BAD_OPT_ACCESS]);
585
586impl LateLintPass<'_> for BadOptAccess {
587    fn check_expr(&mut self, cx: &LateContext<'_>, expr: &hir::Expr<'_>) {
588        let hir::ExprKind::Field(base, target) = expr.kind else { return };
589        let Some(adt_def) = cx.typeck_results().expr_ty(base).ty_adt_def() else { return };
590        // Skip types without `#[rustc_lint_opt_ty]` - only so that the rest of the lint can be
591        // avoided.
592        if !cx.tcx.has_attr(adt_def.did(), sym::rustc_lint_opt_ty) {
593            return;
594        }
595
596        for field in adt_def.all_fields() {
597            if field.name == target.name
598                && let Some(attr) =
599                    cx.tcx.get_attr(field.did, sym::rustc_lint_opt_deny_field_access)
600                && let Some(items) = attr.meta_item_list()
601                && let Some(item) = items.first()
602                && let Some(lit) = item.lit()
603                && let ast::LitKind::Str(val, _) = lit.kind
604            {
605                cx.emit_span_lint(
606                    BAD_OPT_ACCESS,
607                    expr.span,
608                    BadOptAccessDiag { msg: val.as_str() },
609                );
610            }
611        }
612    }
613}
614
615declare_tool_lint! {
616    pub rustc::SPAN_USE_EQ_CTXT,
617    Allow,
618    "forbid uses of `==` with `Span::ctxt`, suggest `Span::eq_ctxt` instead",
619    report_in_external_macro: true
620}
621
622declare_lint_pass!(SpanUseEqCtxt => [SPAN_USE_EQ_CTXT]);
623
624impl<'tcx> LateLintPass<'tcx> for SpanUseEqCtxt {
625    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &hir::Expr<'_>) {
626        if let hir::ExprKind::Binary(
627            hir::BinOp { node: hir::BinOpKind::Eq | hir::BinOpKind::Ne, .. },
628            lhs,
629            rhs,
630        ) = expr.kind
631        {
632            if is_span_ctxt_call(cx, lhs) && is_span_ctxt_call(cx, rhs) {
633                cx.emit_span_lint(SPAN_USE_EQ_CTXT, expr.span, SpanUseEqCtxtDiag);
634            }
635        }
636    }
637}
638
639fn is_span_ctxt_call(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> bool {
640    match &expr.kind {
641        hir::ExprKind::MethodCall(..) => cx
642            .typeck_results()
643            .type_dependent_def_id(expr.hir_id)
644            .is_some_and(|call_did| cx.tcx.is_diagnostic_item(sym::SpanCtxt, call_did)),
645
646        _ => false,
647    }
648}
649
650declare_tool_lint! {
651    /// The `symbol_intern_string_literal` detects `Symbol::intern` being called on a string literal
652    pub rustc::SYMBOL_INTERN_STRING_LITERAL,
653    // rustc_driver crates out of the compiler can't/shouldn't add preinterned symbols;
654    // bootstrap will deny this manually
655    Allow,
656    "Forbid uses of string literals in `Symbol::intern`, suggesting preinterning instead",
657    report_in_external_macro: true
658}
659
660declare_lint_pass!(SymbolInternStringLiteral => [SYMBOL_INTERN_STRING_LITERAL]);
661
662impl<'tcx> LateLintPass<'tcx> for SymbolInternStringLiteral {
663    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx rustc_hir::Expr<'tcx>) {
664        if let hir::ExprKind::Call(path, [arg]) = expr.kind
665            && let hir::ExprKind::Path(ref qpath) = path.kind
666            && let Some(def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id()
667            && cx.tcx.is_diagnostic_item(sym::SymbolIntern, def_id)
668            && let hir::ExprKind::Lit(kind) = arg.kind
669            && let rustc_ast::LitKind::Str(_, _) = kind.node
670        {
671            cx.emit_span_lint(
672                SYMBOL_INTERN_STRING_LITERAL,
673                kind.span,
674                SymbolInternStringLiteralDiag,
675            );
676        }
677    }
678}
rustc_lint/internal.rs

rustc_lint/
internal.rs
