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::def::Res;
5use rustc_hir::def_id::DefId;
6use rustc_hir::{Expr, ExprKind, HirId};
7use rustc_middle::ty::{self, GenericArgsRef, PredicatePolarity, Ty};
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, TypeIrDirectUse,
18    TypeIrInherentUsage, 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
59declare_tool_lint! {
60    /// The `potential_query_instability` lint detects use of methods which can lead to
61    /// potential query instability, such as iterating over a `HashMap`.
62    ///
63    /// Due to the [incremental compilation](https://rustc-dev-guide.rust-lang.org/queries/incremental-compilation.html) model,
64    /// queries must return deterministic, stable results. `HashMap` iteration order can change
65    /// between compilations, and will introduce instability if query results expose the order.
66    pub rustc::POTENTIAL_QUERY_INSTABILITY,
67    Allow,
68    "require explicit opt-in when using potentially unstable methods or functions",
69    report_in_external_macro: true
70}
71
72declare_tool_lint! {
73    /// The `untracked_query_information` lint detects use of methods which leak information not
74    /// tracked by the query system, such as whether a `Steal<T>` value has already been stolen. In
75    /// order not to break incremental compilation, such methods must be used very carefully or not
76    /// at all.
77    pub rustc::UNTRACKED_QUERY_INFORMATION,
78    Allow,
79    "require explicit opt-in when accessing information not tracked by the query system",
80    report_in_external_macro: true
81}
82
83declare_lint_pass!(QueryStability => [POTENTIAL_QUERY_INSTABILITY, UNTRACKED_QUERY_INFORMATION]);
84
85impl<'tcx> LateLintPass<'tcx> for QueryStability {
86    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
87        if let Some((callee_def_id, span, generic_args, _recv, _args)) =
88            get_callee_span_generic_args_and_args(cx, expr)
89            && let Ok(Some(instance)) =
90                ty::Instance::try_resolve(cx.tcx, cx.typing_env(), callee_def_id, generic_args)
91        {
92            let def_id = instance.def_id();
93            if cx.tcx.has_attr(def_id, sym::rustc_lint_query_instability) {
94                cx.emit_span_lint(
95                    POTENTIAL_QUERY_INSTABILITY,
96                    span,
97                    QueryInstability { query: cx.tcx.item_name(def_id) },
98                );
99            } else if has_unstable_into_iter_predicate(cx, callee_def_id, generic_args) {
100                let call_span = span.with_hi(expr.span.hi());
101                cx.emit_span_lint(
102                    POTENTIAL_QUERY_INSTABILITY,
103                    call_span,
104                    QueryInstability { query: sym::into_iter },
105                );
106            }
107
108            if cx.tcx.has_attr(def_id, sym::rustc_lint_untracked_query_information) {
109                cx.emit_span_lint(
110                    UNTRACKED_QUERY_INFORMATION,
111                    span,
112                    QueryUntracked { method: cx.tcx.item_name(def_id) },
113                );
114            }
115        }
116    }
117}
118
119fn has_unstable_into_iter_predicate<'tcx>(
120    cx: &LateContext<'tcx>,
121    callee_def_id: DefId,
122    generic_args: GenericArgsRef<'tcx>,
123) -> bool {
124    let Some(into_iterator_def_id) = cx.tcx.get_diagnostic_item(sym::IntoIterator) else {
125        return false;
126    };
127    let Some(into_iter_fn_def_id) = cx.tcx.lang_items().into_iter_fn() else {
128        return false;
129    };
130    let predicates = cx.tcx.predicates_of(callee_def_id).instantiate(cx.tcx, generic_args);
131    for (predicate, _) in predicates {
132        let Some(trait_pred) = predicate.as_trait_clause() else {
133            continue;
134        };
135        if trait_pred.def_id() != into_iterator_def_id
136            || trait_pred.polarity() != PredicatePolarity::Positive
137        {
138            continue;
139        }
140        // `IntoIterator::into_iter` has no additional method args.
141        let into_iter_fn_args =
142            cx.tcx.instantiate_bound_regions_with_erased(trait_pred).trait_ref.args;
143        let Ok(Some(instance)) = ty::Instance::try_resolve(
144            cx.tcx,
145            cx.typing_env(),
146            into_iter_fn_def_id,
147            into_iter_fn_args,
148        ) else {
149            continue;
150        };
151        // Does the input type's `IntoIterator` implementation have the
152        // `rustc_lint_query_instability` attribute on its `into_iter` method?
153        if cx.tcx.has_attr(instance.def_id(), sym::rustc_lint_query_instability) {
154            return true;
155        }
156    }
157    false
158}
159
160/// Checks whether an expression is a function or method call and, if so, returns its `DefId`,
161/// `Span`, `GenericArgs`, and arguments. This is a slight augmentation of a similarly named Clippy
162/// function, `get_callee_generic_args_and_args`.
163fn get_callee_span_generic_args_and_args<'tcx>(
164    cx: &LateContext<'tcx>,
165    expr: &'tcx Expr<'tcx>,
166) -> Option<(DefId, Span, GenericArgsRef<'tcx>, Option<&'tcx Expr<'tcx>>, &'tcx [Expr<'tcx>])> {
167    if let ExprKind::Call(callee, args) = expr.kind
168        && let callee_ty = cx.typeck_results().expr_ty(callee)
169        && let ty::FnDef(callee_def_id, generic_args) = callee_ty.kind()
170    {
171        return Some((*callee_def_id, callee.span, generic_args, None, args));
172    }
173    if let ExprKind::MethodCall(segment, recv, args, _) = expr.kind
174        && let Some(method_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id)
175    {
176        let generic_args = cx.typeck_results().node_args(expr.hir_id);
177        return Some((method_def_id, segment.ident.span, generic_args, Some(recv), args));
178    }
179    None
180}
181
182declare_tool_lint! {
183    /// The `usage_of_ty_tykind` lint detects usages of `ty::TyKind::<kind>`,
184    /// where `ty::<kind>` would suffice.
185    pub rustc::USAGE_OF_TY_TYKIND,
186    Allow,
187    "usage of `ty::TyKind` outside of the `ty::sty` module",
188    report_in_external_macro: true
189}
190
191declare_tool_lint! {
192    /// The `usage_of_qualified_ty` lint detects usages of `ty::TyKind`,
193    /// where `Ty` should be used instead.
194    pub rustc::USAGE_OF_QUALIFIED_TY,
195    Allow,
196    "using `ty::{Ty,TyCtxt}` instead of importing it",
197    report_in_external_macro: true
198}
199
200declare_lint_pass!(TyTyKind => [
201    USAGE_OF_TY_TYKIND,
202    USAGE_OF_QUALIFIED_TY,
203]);
204
205impl<'tcx> LateLintPass<'tcx> for TyTyKind {
206    fn check_path(
207        &mut self,
208        cx: &LateContext<'tcx>,
209        path: &rustc_hir::Path<'tcx>,
210        _: rustc_hir::HirId,
211    ) {
212        if let Some(segment) = path.segments.iter().nth_back(1)
213            && lint_ty_kind_usage(cx, &segment.res)
214        {
215            let span =
216                path.span.with_hi(segment.args.map_or(segment.ident.span, |a| a.span_ext).hi());
217            cx.emit_span_lint(USAGE_OF_TY_TYKIND, path.span, TykindKind { suggestion: span });
218        }
219    }
220
221    fn check_ty(&mut self, cx: &LateContext<'_>, ty: &'tcx hir::Ty<'tcx, hir::AmbigArg>) {
222        match &ty.kind {
223            hir::TyKind::Path(hir::QPath::Resolved(_, path)) => {
224                if lint_ty_kind_usage(cx, &path.res) {
225                    let span = match cx.tcx.parent_hir_node(ty.hir_id) {
226                        hir::Node::PatExpr(hir::PatExpr {
227                            kind: hir::PatExprKind::Path(qpath),
228                            ..
229                        })
230                        | hir::Node::Pat(hir::Pat {
231                            kind:
232                                hir::PatKind::TupleStruct(qpath, ..) | hir::PatKind::Struct(qpath, ..),
233                            ..
234                        })
235                        | hir::Node::Expr(
236                            hir::Expr { kind: hir::ExprKind::Path(qpath), .. }
237                            | &hir::Expr { kind: hir::ExprKind::Struct(qpath, ..), .. },
238                        ) => {
239                            if let hir::QPath::TypeRelative(qpath_ty, ..) = qpath
240                                && qpath_ty.hir_id == ty.hir_id
241                            {
242                                Some(path.span)
243                            } else {
244                                None
245                            }
246                        }
247                        _ => None,
248                    };
249
250                    match span {
251                        Some(span) => {
252                            cx.emit_span_lint(
253                                USAGE_OF_TY_TYKIND,
254                                path.span,
255                                TykindKind { suggestion: span },
256                            );
257                        }
258                        None => cx.emit_span_lint(USAGE_OF_TY_TYKIND, path.span, TykindDiag),
259                    }
260                } else if !ty.span.from_expansion()
261                    && path.segments.len() > 1
262                    && let Some(ty) = is_ty_or_ty_ctxt(cx, path)
263                {
264                    cx.emit_span_lint(
265                        USAGE_OF_QUALIFIED_TY,
266                        path.span,
267                        TyQualified { ty, suggestion: path.span },
268                    );
269                }
270            }
271            _ => {}
272        }
273    }
274}
275
276fn lint_ty_kind_usage(cx: &LateContext<'_>, res: &Res) -> bool {
277    if let Some(did) = res.opt_def_id() {
278        cx.tcx.is_diagnostic_item(sym::TyKind, did) || cx.tcx.is_diagnostic_item(sym::IrTyKind, did)
279    } else {
280        false
281    }
282}
283
284fn is_ty_or_ty_ctxt(cx: &LateContext<'_>, path: &hir::Path<'_>) -> Option<String> {
285    match &path.res {
286        Res::Def(_, def_id) => {
287            if let Some(name @ (sym::Ty | sym::TyCtxt)) = cx.tcx.get_diagnostic_name(*def_id) {
288                return Some(format!("{}{}", name, gen_args(path.segments.last().unwrap())));
289            }
290        }
291        // Only lint on `&Ty` and `&TyCtxt` if it is used outside of a trait.
292        Res::SelfTyAlias { alias_to: did, is_trait_impl: false, .. } => {
293            if let ty::Adt(adt, args) = cx.tcx.type_of(did).instantiate_identity().kind()
294                && let Some(name @ (sym::Ty | sym::TyCtxt)) = cx.tcx.get_diagnostic_name(adt.did())
295            {
296                return Some(format!("{}<{}>", name, args[0]));
297            }
298        }
299        _ => (),
300    }
301
302    None
303}
304
305fn gen_args(segment: &hir::PathSegment<'_>) -> String {
306    if let Some(args) = &segment.args {
307        let lifetimes = args
308            .args
309            .iter()
310            .filter_map(|arg| {
311                if let hir::GenericArg::Lifetime(lt) = arg {
312                    Some(lt.ident.to_string())
313                } else {
314                    None
315                }
316            })
317            .collect::<Vec<_>>();
318
319        if !lifetimes.is_empty() {
320            return format!("<{}>", lifetimes.join(", "));
321        }
322    }
323
324    String::new()
325}
326
327declare_tool_lint! {
328    /// The `non_glob_import_of_type_ir_inherent_item` lint detects
329    /// non-glob imports of module `rustc_type_ir::inherent`.
330    pub rustc::NON_GLOB_IMPORT_OF_TYPE_IR_INHERENT,
331    Allow,
332    "non-glob import of `rustc_type_ir::inherent`",
333    report_in_external_macro: true
334}
335
336declare_tool_lint! {
337    /// The `usage_of_type_ir_inherent` lint detects usage of `rustc_type_ir::inherent`.
338    ///
339    /// This module should only be used within the trait solver.
340    pub rustc::USAGE_OF_TYPE_IR_INHERENT,
341    Allow,
342    "usage `rustc_type_ir::inherent` outside of trait system",
343    report_in_external_macro: true
344}
345
346declare_tool_lint! {
347    /// The `usage_of_type_ir_traits` lint detects usage of `rustc_type_ir::Interner`,
348    /// or `rustc_infer::InferCtxtLike`.
349    ///
350    /// Methods of this trait should only be used within the type system abstraction layer,
351    /// and in the generic next trait solver implementation. Look for an analogously named
352    /// method on `TyCtxt` or `InferCtxt` (respectively).
353    pub rustc::USAGE_OF_TYPE_IR_TRAITS,
354    Allow,
355    "usage `rustc_type_ir`-specific abstraction traits outside of trait system",
356    report_in_external_macro: true
357}
358declare_tool_lint! {
359    /// The `direct_use_of_rustc_type_ir` lint detects usage of `rustc_type_ir`.
360    ///
361    /// This module should only be used within the trait solver and some desirable
362    /// crates like rustc_middle.
363    pub rustc::DIRECT_USE_OF_RUSTC_TYPE_IR,
364    Allow,
365    "usage `rustc_type_ir` abstraction outside of trait system",
366    report_in_external_macro: true
367}
368
369declare_lint_pass!(TypeIr => [DIRECT_USE_OF_RUSTC_TYPE_IR, NON_GLOB_IMPORT_OF_TYPE_IR_INHERENT, USAGE_OF_TYPE_IR_INHERENT, USAGE_OF_TYPE_IR_TRAITS]);
370
371impl<'tcx> LateLintPass<'tcx> for TypeIr {
372    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'tcx>) {
373        let res_def_id = match expr.kind {
374            hir::ExprKind::Path(hir::QPath::Resolved(_, path)) => path.res.opt_def_id(),
375            hir::ExprKind::Path(hir::QPath::TypeRelative(..)) | hir::ExprKind::MethodCall(..) => {
376                cx.typeck_results().type_dependent_def_id(expr.hir_id)
377            }
378            _ => return,
379        };
380        let Some(res_def_id) = res_def_id else {
381            return;
382        };
383        if let Some(assoc_item) = cx.tcx.opt_associated_item(res_def_id)
384            && let Some(trait_def_id) = assoc_item.trait_container(cx.tcx)
385            && (cx.tcx.is_diagnostic_item(sym::type_ir_interner, trait_def_id)
386                | cx.tcx.is_diagnostic_item(sym::type_ir_infer_ctxt_like, trait_def_id))
387        {
388            cx.emit_span_lint(USAGE_OF_TYPE_IR_TRAITS, expr.span, TypeIrTraitUsage);
389        }
390    }
391
392    fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::Item<'tcx>) {
393        let rustc_hir::ItemKind::Use(path, kind) = item.kind else { return };
394
395        let is_mod_inherent = |res: Res| {
396            res.opt_def_id()
397                .is_some_and(|def_id| cx.tcx.is_diagnostic_item(sym::type_ir_inherent, def_id))
398        };
399
400        // Path segments except for the final.
401        if let Some(seg) = path.segments.iter().find(|seg| is_mod_inherent(seg.res)) {
402            cx.emit_span_lint(USAGE_OF_TYPE_IR_INHERENT, seg.ident.span, TypeIrInherentUsage);
403        }
404        // Final path resolutions, like `use rustc_type_ir::inherent`
405        else if let Some(type_ns) = path.res.type_ns
406            && is_mod_inherent(type_ns)
407        {
408            cx.emit_span_lint(
409                USAGE_OF_TYPE_IR_INHERENT,
410                path.segments.last().unwrap().ident.span,
411                TypeIrInherentUsage,
412            );
413        }
414
415        let (lo, hi, snippet) = match path.segments {
416            [.., penultimate, segment] if is_mod_inherent(penultimate.res) => {
417                (segment.ident.span, item.kind.ident().unwrap().span, "*")
418            }
419            [.., segment]
420                if let Some(type_ns) = path.res.type_ns
421                    && is_mod_inherent(type_ns)
422                    && let rustc_hir::UseKind::Single(ident) = kind =>
423            {
424                let (lo, snippet) =
425                    match cx.tcx.sess.source_map().span_to_snippet(path.span).as_deref() {
426                        Ok("self") => (path.span, "*"),
427                        _ => (segment.ident.span.shrink_to_hi(), "::*"),
428                    };
429                (lo, if segment.ident == ident { lo } else { ident.span }, snippet)
430            }
431            _ => return,
432        };
433        cx.emit_span_lint(
434            NON_GLOB_IMPORT_OF_TYPE_IR_INHERENT,
435            path.span,
436            NonGlobImportTypeIrInherent { suggestion: lo.eq_ctxt(hi).then(|| lo.to(hi)), snippet },
437        );
438    }
439
440    fn check_path(
441        &mut self,
442        cx: &LateContext<'tcx>,
443        path: &rustc_hir::Path<'tcx>,
444        _: rustc_hir::HirId,
445    ) {
446        if let Some(seg) = path.segments.iter().find(|seg| {
447            seg.res
448                .opt_def_id()
449                .is_some_and(|def_id| cx.tcx.is_diagnostic_item(sym::type_ir, def_id))
450        }) {
451            cx.emit_span_lint(DIRECT_USE_OF_RUSTC_TYPE_IR, seg.ident.span, TypeIrDirectUse);
452        }
453    }
454}
455
456declare_tool_lint! {
457    /// The `lint_pass_impl_without_macro` detects manual implementations of a lint
458    /// pass, without using [`declare_lint_pass`] or [`impl_lint_pass`].
459    pub rustc::LINT_PASS_IMPL_WITHOUT_MACRO,
460    Allow,
461    "`impl LintPass` without the `declare_lint_pass!` or `impl_lint_pass!` macros"
462}
463
464declare_lint_pass!(LintPassImpl => [LINT_PASS_IMPL_WITHOUT_MACRO]);
465
466impl EarlyLintPass for LintPassImpl {
467    fn check_item(&mut self, cx: &EarlyContext<'_>, item: &ast::Item) {
468        if let ast::ItemKind::Impl(ast::Impl { of_trait: Some(of_trait), .. }) = &item.kind
469            && let Some(last) = of_trait.trait_ref.path.segments.last()
470            && last.ident.name == sym::LintPass
471        {
472            let expn_data = of_trait.trait_ref.path.span.ctxt().outer_expn_data();
473            let call_site = expn_data.call_site;
474            if expn_data.kind != ExpnKind::Macro(MacroKind::Bang, sym::impl_lint_pass)
475                && call_site.ctxt().outer_expn_data().kind
476                    != ExpnKind::Macro(MacroKind::Bang, sym::declare_lint_pass)
477            {
478                cx.emit_span_lint(
479                    LINT_PASS_IMPL_WITHOUT_MACRO,
480                    of_trait.trait_ref.path.span,
481                    LintPassByHand,
482                );
483            }
484        }
485    }
486}
487
488declare_tool_lint! {
489    /// The `untranslatable_diagnostic` lint detects messages passed to functions with `impl
490    /// Into<{D,Subd}iagMessage` parameters without using translatable Fluent strings.
491    ///
492    /// More details on translatable diagnostics can be found
493    /// [here](https://rustc-dev-guide.rust-lang.org/diagnostics/translation.html).
494    pub rustc::UNTRANSLATABLE_DIAGNOSTIC,
495    Allow,
496    "prevent creation of diagnostics which cannot be translated",
497    report_in_external_macro: true,
498    @eval_always = true
499}
500
501declare_tool_lint! {
502    /// The `diagnostic_outside_of_impl` lint detects calls to functions annotated with
503    /// `#[rustc_lint_diagnostics]` that are outside an `Diagnostic`, `Subdiagnostic`, or
504    /// `LintDiagnostic` impl (either hand-written or derived).
505    ///
506    /// More details on diagnostics implementations can be found
507    /// [here](https://rustc-dev-guide.rust-lang.org/diagnostics/diagnostic-structs.html).
508    pub rustc::DIAGNOSTIC_OUTSIDE_OF_IMPL,
509    Allow,
510    "prevent diagnostic creation outside of `Diagnostic`/`Subdiagnostic`/`LintDiagnostic` impls",
511    report_in_external_macro: true,
512    @eval_always = true
513}
514
515declare_lint_pass!(Diagnostics => [UNTRANSLATABLE_DIAGNOSTIC, DIAGNOSTIC_OUTSIDE_OF_IMPL]);
516
517impl LateLintPass<'_> for Diagnostics {
518    fn check_expr<'tcx>(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'tcx>) {
519        let collect_args_tys_and_spans = |args: &[hir::Expr<'_>], reserve_one_extra: bool| {
520            let mut result = Vec::with_capacity(args.len() + usize::from(reserve_one_extra));
521            result.extend(args.iter().map(|arg| (cx.typeck_results().expr_ty(arg), arg.span)));
522            result
523        };
524        // Only check function calls and method calls.
525        let Some((def_id, span, fn_gen_args, recv, args)) =
526            get_callee_span_generic_args_and_args(cx, expr)
527        else {
528            return;
529        };
530        let mut arg_tys_and_spans = collect_args_tys_and_spans(args, recv.is_some());
531        if let Some(recv) = recv {
532            arg_tys_and_spans.insert(0, (cx.tcx.types.self_param, recv.span)); // dummy inserted for `self`
533        }
534
535        Self::diagnostic_outside_of_impl(cx, span, expr.hir_id, def_id, fn_gen_args);
536        Self::untranslatable_diagnostic(cx, def_id, &arg_tys_and_spans);
537    }
538}
539
540impl Diagnostics {
541    // Is the type `{D,Subd}iagMessage`?
542    fn is_diag_message<'cx>(cx: &LateContext<'cx>, ty: Ty<'cx>) -> bool {
543        if let Some(adt_def) = ty.ty_adt_def()
544            && let Some(name) = cx.tcx.get_diagnostic_name(adt_def.did())
545            && matches!(name, sym::DiagMessage | sym::SubdiagMessage)
546        {
547            true
548        } else {
549            false
550        }
551    }
552
553    fn untranslatable_diagnostic<'cx>(
554        cx: &LateContext<'cx>,
555        def_id: DefId,
556        arg_tys_and_spans: &[(Ty<'cx>, Span)],
557    ) {
558        let fn_sig = cx.tcx.fn_sig(def_id).instantiate_identity().skip_binder();
559        let predicates = cx.tcx.predicates_of(def_id).instantiate_identity(cx.tcx).predicates;
560        for (i, &param_ty) in fn_sig.inputs().iter().enumerate() {
561            if let ty::Param(sig_param) = param_ty.kind() {
562                // It is a type parameter. Check if it is `impl Into<{D,Subd}iagMessage>`.
563                for pred in predicates.iter() {
564                    if let Some(trait_pred) = pred.as_trait_clause()
565                        && let trait_ref = trait_pred.skip_binder().trait_ref
566                        && trait_ref.self_ty() == param_ty // correct predicate for the param?
567                        && cx.tcx.is_diagnostic_item(sym::Into, trait_ref.def_id)
568                        && let ty1 = trait_ref.args.type_at(1)
569                        && Self::is_diag_message(cx, ty1)
570                    {
571                        // Calls to methods with an `impl Into<{D,Subd}iagMessage>` parameter must be passed an arg
572                        // with type `{D,Subd}iagMessage` or `impl Into<{D,Subd}iagMessage>`. Otherwise, emit an
573                        // `UNTRANSLATABLE_DIAGNOSTIC` lint.
574                        let (arg_ty, arg_span) = arg_tys_and_spans[i];
575
576                        // Is the arg type `{Sub,D}iagMessage`or `impl Into<{Sub,D}iagMessage>`?
577                        let is_translatable = Self::is_diag_message(cx, arg_ty)
578                            || matches!(arg_ty.kind(), ty::Param(arg_param) if arg_param.name == sig_param.name);
579                        if !is_translatable {
580                            cx.emit_span_lint(
581                                UNTRANSLATABLE_DIAGNOSTIC,
582                                arg_span,
583                                UntranslatableDiag,
584                            );
585                        }
586                    }
587                }
588            }
589        }
590    }
591
592    fn diagnostic_outside_of_impl<'cx>(
593        cx: &LateContext<'cx>,
594        span: Span,
595        current_id: HirId,
596        def_id: DefId,
597        fn_gen_args: GenericArgsRef<'cx>,
598    ) {
599        // Is the callee marked with `#[rustc_lint_diagnostics]`?
600        let Some(inst) =
601            ty::Instance::try_resolve(cx.tcx, cx.typing_env(), def_id, fn_gen_args).ok().flatten()
602        else {
603            return;
604        };
605        let has_attr = cx.tcx.has_attr(inst.def_id(), sym::rustc_lint_diagnostics);
606        if !has_attr {
607            return;
608        };
609
610        for (hir_id, _parent) in cx.tcx.hir_parent_iter(current_id) {
611            if let Some(owner_did) = hir_id.as_owner()
612                && cx.tcx.has_attr(owner_did, sym::rustc_lint_diagnostics)
613            {
614                // The parent method is marked with `#[rustc_lint_diagnostics]`
615                return;
616            }
617        }
618
619        // Calls to `#[rustc_lint_diagnostics]`-marked functions should only occur:
620        // - inside an impl of `Diagnostic`, `Subdiagnostic`, or `LintDiagnostic`, or
621        // - inside a parent function that is itself marked with `#[rustc_lint_diagnostics]`.
622        //
623        // Otherwise, emit a `DIAGNOSTIC_OUTSIDE_OF_IMPL` lint.
624        let mut is_inside_appropriate_impl = false;
625        for (_hir_id, parent) in cx.tcx.hir_parent_iter(current_id) {
626            debug!(?parent);
627            if let hir::Node::Item(hir::Item { kind: hir::ItemKind::Impl(impl_), .. }) = parent
628                && let Some(of_trait) = impl_.of_trait
629                && let Some(def_id) = of_trait.trait_ref.trait_def_id()
630                && let Some(name) = cx.tcx.get_diagnostic_name(def_id)
631                && matches!(name, sym::Diagnostic | sym::Subdiagnostic | sym::LintDiagnostic)
632            {
633                is_inside_appropriate_impl = true;
634                break;
635            }
636        }
637        debug!(?is_inside_appropriate_impl);
638        if !is_inside_appropriate_impl {
639            cx.emit_span_lint(DIAGNOSTIC_OUTSIDE_OF_IMPL, span, DiagOutOfImpl);
640        }
641    }
642}
643
644declare_tool_lint! {
645    /// The `bad_opt_access` lint detects accessing options by field instead of
646    /// the wrapper function.
647    pub rustc::BAD_OPT_ACCESS,
648    Deny,
649    "prevent using options by field access when there is a wrapper function",
650    report_in_external_macro: true
651}
652
653declare_lint_pass!(BadOptAccess => [BAD_OPT_ACCESS]);
654
655impl LateLintPass<'_> for BadOptAccess {
656    fn check_expr(&mut self, cx: &LateContext<'_>, expr: &hir::Expr<'_>) {
657        let hir::ExprKind::Field(base, target) = expr.kind else { return };
658        let Some(adt_def) = cx.typeck_results().expr_ty(base).ty_adt_def() else { return };
659        // Skip types without `#[rustc_lint_opt_ty]` - only so that the rest of the lint can be
660        // avoided.
661        if !cx.tcx.has_attr(adt_def.did(), sym::rustc_lint_opt_ty) {
662            return;
663        }
664
665        for field in adt_def.all_fields() {
666            if field.name == target.name
667                && let Some(attr) =
668                    cx.tcx.get_attr(field.did, sym::rustc_lint_opt_deny_field_access)
669                && let Some(items) = attr.meta_item_list()
670                && let Some(item) = items.first()
671                && let Some(lit) = item.lit()
672                && let ast::LitKind::Str(val, _) = lit.kind
673            {
674                cx.emit_span_lint(
675                    BAD_OPT_ACCESS,
676                    expr.span,
677                    BadOptAccessDiag { msg: val.as_str() },
678                );
679            }
680        }
681    }
682}
683
684declare_tool_lint! {
685    pub rustc::SPAN_USE_EQ_CTXT,
686    Allow,
687    "forbid uses of `==` with `Span::ctxt`, suggest `Span::eq_ctxt` instead",
688    report_in_external_macro: true
689}
690
691declare_lint_pass!(SpanUseEqCtxt => [SPAN_USE_EQ_CTXT]);
692
693impl<'tcx> LateLintPass<'tcx> for SpanUseEqCtxt {
694    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &hir::Expr<'_>) {
695        if let hir::ExprKind::Binary(
696            hir::BinOp { node: hir::BinOpKind::Eq | hir::BinOpKind::Ne, .. },
697            lhs,
698            rhs,
699        ) = expr.kind
700        {
701            if is_span_ctxt_call(cx, lhs) && is_span_ctxt_call(cx, rhs) {
702                cx.emit_span_lint(SPAN_USE_EQ_CTXT, expr.span, SpanUseEqCtxtDiag);
703            }
704        }
705    }
706}
707
708fn is_span_ctxt_call(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> bool {
709    match &expr.kind {
710        hir::ExprKind::MethodCall(..) => cx
711            .typeck_results()
712            .type_dependent_def_id(expr.hir_id)
713            .is_some_and(|call_did| cx.tcx.is_diagnostic_item(sym::SpanCtxt, call_did)),
714
715        _ => false,
716    }
717}
718
719declare_tool_lint! {
720    /// The `symbol_intern_string_literal` detects `Symbol::intern` being called on a string literal
721    pub rustc::SYMBOL_INTERN_STRING_LITERAL,
722    // rustc_driver crates out of the compiler can't/shouldn't add preinterned symbols;
723    // bootstrap will deny this manually
724    Allow,
725    "Forbid uses of string literals in `Symbol::intern`, suggesting preinterning instead",
726    report_in_external_macro: true
727}
728
729declare_lint_pass!(SymbolInternStringLiteral => [SYMBOL_INTERN_STRING_LITERAL]);
730
731impl<'tcx> LateLintPass<'tcx> for SymbolInternStringLiteral {
732    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx rustc_hir::Expr<'tcx>) {
733        if let hir::ExprKind::Call(path, [arg]) = expr.kind
734            && let hir::ExprKind::Path(ref qpath) = path.kind
735            && let Some(def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id()
736            && cx.tcx.is_diagnostic_item(sym::SymbolIntern, def_id)
737            && let hir::ExprKind::Lit(kind) = arg.kind
738            && let rustc_ast::LitKind::Str(_, _) = kind.node
739        {
740            cx.emit_span_lint(
741                SYMBOL_INTERN_STRING_LITERAL,
742                kind.span,
743                SymbolInternStringLiteralDiag,
744            );
745        }
746    }
747}
rustc_lint/internal.rs

rustc_lint/
internal.rs
