1 use crate::diagnostics::{ImportSuggestion, LabelSuggestion, TypoSuggestion};
2 use crate::late::{AliasPossibility, LateResolutionVisitor, RibKind};
3 use crate::late::{LifetimeBinderKind, LifetimeRes, LifetimeRibKind, LifetimeUseSet};
4 use crate::path_names_to_string;
5 use crate::{Module, ModuleKind, ModuleOrUniformRoot};
6 use crate::{PathResult, PathSource, Segment};
8 use rustc_ast::visit::{FnCtxt, FnKind, LifetimeCtxt};
10 self as ast, AssocItemKind, Expr, ExprKind, GenericParam, GenericParamKind, Item, ItemKind,
11 MethodCall, NodeId, Path, Ty, TyKind, DUMMY_NODE_ID,
13 use rustc_ast_pretty::pprust::path_segment_to_string;
14 use rustc_data_structures::fx::FxHashSet;
16 pluralize, struct_span_err, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed,
20 use rustc_hir::def::Namespace::{self, *};
21 use rustc_hir::def::{self, CtorKind, CtorOf, DefKind};
22 use rustc_hir::def_id::{DefId, CRATE_DEF_ID, LOCAL_CRATE};
23 use rustc_hir::PrimTy;
24 use rustc_session::lint;
25 use rustc_session::parse::feature_err;
26 use rustc_session::Session;
27 use rustc_span::edition::Edition;
28 use rustc_span::hygiene::MacroKind;
29 use rustc_span::lev_distance::find_best_match_for_name;
30 use rustc_span::symbol::{kw, sym, Ident, Symbol};
31 use rustc_span::{BytePos, Span};
36 type Res = def::Res<ast::NodeId>;
38 /// A field or associated item from self type suggested in case of resolution failure.
39 enum AssocSuggestion {
41 MethodWithSelf { called: bool },
42 AssocFn { called: bool },
47 impl AssocSuggestion {
48 fn action(&self) -> &'static str {
50 AssocSuggestion::Field => "use the available field",
51 AssocSuggestion::MethodWithSelf { called: true } => {
52 "call the method with the fully-qualified path"
54 AssocSuggestion::MethodWithSelf { called: false } => {
55 "refer to the method with the fully-qualified path"
57 AssocSuggestion::AssocFn { called: true } => "call the associated function",
58 AssocSuggestion::AssocFn { called: false } => "refer to the associated function",
59 AssocSuggestion::AssocConst => "use the associated `const`",
60 AssocSuggestion::AssocType => "use the associated type",
65 fn is_self_type(path: &[Segment], namespace: Namespace) -> bool {
66 namespace == TypeNS && path.len() == 1 && path[0].ident.name == kw::SelfUpper
69 fn is_self_value(path: &[Segment], namespace: Namespace) -> bool {
70 namespace == ValueNS && path.len() == 1 && path[0].ident.name == kw::SelfLower
73 /// Gets the stringified path for an enum from an `ImportSuggestion` for an enum variant.
74 fn import_candidate_to_enum_paths(suggestion: &ImportSuggestion) -> (String, String) {
75 let variant_path = &suggestion.path;
76 let variant_path_string = path_names_to_string(variant_path);
78 let path_len = suggestion.path.segments.len();
79 let enum_path = ast::Path {
80 span: suggestion.path.span,
81 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
84 let enum_path_string = path_names_to_string(&enum_path);
86 (variant_path_string, enum_path_string)
89 /// Description of an elided lifetime.
90 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug)]
91 pub(super) struct MissingLifetime {
92 /// Used to overwrite the resolution with the suggestion, to avoid cascasing errors.
94 /// Where to suggest adding the lifetime.
96 /// How the lifetime was introduced, to have the correct space and comma.
97 pub kind: MissingLifetimeKind,
98 /// Number of elided lifetimes, used for elision in path.
102 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug)]
103 pub(super) enum MissingLifetimeKind {
104 /// An explicit `'_`.
106 /// An elided lifetime `&' ty`.
108 /// An elided lifetime in brackets with written brackets.
110 /// An elided lifetime with elided brackets.
114 /// Description of the lifetimes appearing in a function parameter.
115 /// This is used to provide a literal explanation to the elision failure.
116 #[derive(Clone, Debug)]
117 pub(super) struct ElisionFnParameter {
118 /// The index of the argument in the original definition.
120 /// The name of the argument if it's a simple ident.
121 pub ident: Option<Ident>,
122 /// The number of lifetimes in the parameter.
123 pub lifetime_count: usize,
124 /// The span of the parameter.
128 /// Description of lifetimes that appear as candidates for elision.
129 /// This is used to suggest introducing an explicit lifetime.
131 pub(super) enum LifetimeElisionCandidate {
132 /// This is not a real lifetime.
134 /// There is a named lifetime, we won't suggest anything.
136 Missing(MissingLifetime),
139 /// Only used for diagnostics.
143 fallback_label: String,
145 span_label: Option<(Span, &'static str)>,
147 suggestion: Option<(Span, &'static str, String)>,
152 Typo(TypoSuggestion),
153 Shadowed(Res, Option<Span>),
158 fn to_opt_suggestion(self) -> Option<TypoSuggestion> {
160 TypoCandidate::Typo(sugg) => Some(sugg),
161 TypoCandidate::Shadowed(_, _) | TypoCandidate::None => None,
166 impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
167 fn def_span(&self, def_id: DefId) -> Option<Span> {
169 LOCAL_CRATE => self.r.opt_span(def_id),
170 _ => Some(self.r.cstore().get_span_untracked(def_id, self.r.session)),
178 source: PathSource<'_>,
181 // Make the base error.
182 let mut expected = source.descr_expected();
183 let path_str = Segment::names_to_string(path);
184 let item_str = path.last().unwrap().ident;
185 if let Some(res) = res {
187 msg: format!("expected {}, found {} `{}`", expected, res.descr(), path_str),
188 fallback_label: format!("not a {expected}"),
190 span_label: match res {
191 Res::Def(kind, def_id) if kind == DefKind::TyParam => {
192 self.def_span(def_id).map(|span| (span, "found this type parameter"))
196 could_be_expr: match res {
197 Res::Def(DefKind::Fn, _) => {
198 // Verify whether this is a fn call or an Fn used as a type.
202 .span_to_snippet(span)
203 .map(|snippet| snippet.ends_with(')'))
207 DefKind::Ctor(..) | DefKind::AssocFn | DefKind::Const | DefKind::AssocConst,
212 | Res::Local(_) => true,
218 let item_span = path.last().unwrap().ident.span;
219 let (mod_prefix, mod_str, suggestion) = if path.len() == 1 {
220 debug!(?self.diagnostic_metadata.current_impl_items);
221 debug!(?self.diagnostic_metadata.current_function);
222 let suggestion = if self.current_trait_ref.is_none()
223 && let Some((fn_kind, _)) = self.diagnostic_metadata.current_function
224 && let Some(FnCtxt::Assoc(_)) = fn_kind.ctxt()
225 && let Some(items) = self.diagnostic_metadata.current_impl_items
226 && let Some(item) = items.iter().find(|i| {
227 if let AssocItemKind::Fn(_) = &i.kind && i.ident.name == item_str.name
229 debug!(?item_str.name);
234 && let AssocItemKind::Fn(fn_) = &item.kind
237 let self_sugg = if fn_.sig.decl.has_self() { "self." } else { "Self::" };
239 item_span.shrink_to_lo(),
240 "consider using the associated function",
241 self_sugg.to_string()
246 (String::new(), "this scope".to_string(), suggestion)
247 } else if path.len() == 2 && path[0].ident.name == kw::PathRoot {
248 if self.r.session.edition() > Edition::Edition2015 {
249 // In edition 2018 onwards, the `::foo` syntax may only pull from the extern prelude
250 // which overrides all other expectations of item type
252 (String::new(), "the list of imported crates".to_string(), None)
254 (String::new(), "the crate root".to_string(), None)
256 } else if path.len() == 2 && path[0].ident.name == kw::Crate {
257 (String::new(), "the crate root".to_string(), None)
259 let mod_path = &path[..path.len() - 1];
260 let mod_prefix = match self.resolve_path(mod_path, Some(TypeNS), None) {
261 PathResult::Module(ModuleOrUniformRoot::Module(module)) => module.res(),
264 .map_or_else(String::new, |res| format!("{} ", res.descr()));
265 (mod_prefix, format!("`{}`", Segment::names_to_string(mod_path)), None)
268 let (fallback_label, suggestion) = if path_str == "async"
269 && expected.starts_with("struct")
271 ("`async` blocks are only allowed in Rust 2018 or later".to_string(), suggestion)
273 // check if we are in situation of typo like `True` instead of `true`.
274 let override_suggestion =
275 if ["true", "false"].contains(&item_str.to_string().to_lowercase().as_str()) {
276 let item_typo = item_str.to_string().to_lowercase();
279 "you may want to use a bool value instead",
280 format!("{}", item_typo),
285 (format!("not found in {mod_str}"), override_suggestion)
289 msg: format!("cannot find {expected} `{item_str}` in {mod_prefix}{mod_str}"),
293 could_be_expr: false,
299 /// Handles error reporting for `smart_resolve_path_fragment` function.
300 /// Creates base error and amends it with one short label and possibly some longer helps/notes.
301 pub(crate) fn smart_resolve_report_errors(
305 source: PathSource<'_>,
307 ) -> (DiagnosticBuilder<'a, ErrorGuaranteed>, Vec<ImportSuggestion>) {
308 debug!(?res, ?source);
309 let base_error = self.make_base_error(path, span, source, res);
310 let code = source.error_code(res.is_some());
312 self.r.session.struct_span_err_with_code(base_error.span, &base_error.msg, code);
314 self.suggest_swapping_misplaced_self_ty_and_trait(&mut err, source, res, base_error.span);
316 if let Some((span, label)) = base_error.span_label {
317 err.span_label(span, label);
320 if let Some(ref sugg) = base_error.suggestion {
321 err.span_suggestion_verbose(sugg.0, sugg.1, &sugg.2, Applicability::MaybeIncorrect);
324 self.suggest_bare_struct_literal(&mut err);
326 if self.suggest_pattern_match_with_let(&mut err, source, span) {
328 err.span_label(base_error.span, &base_error.fallback_label);
329 return (err, Vec::new());
332 self.suggest_self_or_self_ref(&mut err, path, span);
333 self.detect_assoct_type_constraint_meant_as_path(&mut err, &base_error);
334 if self.suggest_self_ty(&mut err, source, path, span)
335 || self.suggest_self_value(&mut err, source, path, span)
337 return (err, Vec::new());
340 let (found, candidates) =
341 self.try_lookup_name_relaxed(&mut err, source, path, span, res, &base_error);
343 return (err, candidates);
346 if !self.type_ascription_suggestion(&mut err, base_error.span) {
348 self.suggest_trait_and_bounds(&mut err, source, res, span, &base_error);
350 // if we have suggested using pattern matching, then don't add needless suggestions
352 fallback |= self.suggest_typo(&mut err, source, path, span, &base_error);
356 err.span_label(base_error.span, &base_error.fallback_label);
359 self.err_code_special_cases(&mut err, source, path, span);
364 fn detect_assoct_type_constraint_meant_as_path(
366 err: &mut Diagnostic,
367 base_error: &BaseError,
369 let Some(ty) = self.diagnostic_metadata.current_type_path else { return; };
370 let TyKind::Path(_, path) = &ty.kind else { return; };
371 for segment in &path.segments {
372 let Some(params) = &segment.args else { continue; };
373 let ast::GenericArgs::AngleBracketed(ref params) = params.deref() else { continue; };
374 for param in ¶ms.args {
375 let ast::AngleBracketedArg::Constraint(constraint) = param else { continue; };
376 let ast::AssocConstraintKind::Bound { bounds } = &constraint.kind else {
379 for bound in bounds {
380 let ast::GenericBound::Trait(trait_ref, ast::TraitBoundModifier::None)
385 if base_error.span == trait_ref.span {
386 err.span_suggestion_verbose(
387 constraint.ident.span.between(trait_ref.span),
388 "you might have meant to write a path instead of an associated type bound",
390 Applicability::MachineApplicable,
398 fn suggest_self_or_self_ref(&mut self, err: &mut Diagnostic, path: &[Segment], span: Span) {
399 if !self.self_type_is_available() {
402 let Some(path_last_segment) = path.last() else { return };
403 let item_str = path_last_segment.ident;
404 // Emit help message for fake-self from other languages (e.g., `this` in Javascript).
405 if ["this", "my"].contains(&item_str.as_str()) {
406 err.span_suggestion_short(
408 "you might have meant to use `self` here instead",
410 Applicability::MaybeIncorrect,
412 if !self.self_value_is_available(path[0].ident.span) {
413 if let Some((FnKind::Fn(_, _, sig, ..), fn_span)) =
414 &self.diagnostic_metadata.current_function
416 let (span, sugg) = if let Some(param) = sig.decl.inputs.get(0) {
417 (param.span.shrink_to_lo(), "&self, ")
423 .span_through_char(*fn_span, '(')
428 err.span_suggestion_verbose(
430 "if you meant to use `self`, you are also missing a `self` receiver \
433 Applicability::MaybeIncorrect,
440 fn try_lookup_name_relaxed(
442 err: &mut Diagnostic,
443 source: PathSource<'_>,
447 base_error: &BaseError,
448 ) -> (bool, Vec<ImportSuggestion>) {
449 // Try to lookup name in more relaxed fashion for better error reporting.
450 let ident = path.last().unwrap().ident;
451 let is_expected = &|res| source.is_expected(res);
452 let ns = source.namespace();
453 let is_enum_variant = &|res| matches!(res, Res::Def(DefKind::Variant, _));
454 let path_str = Segment::names_to_string(path);
455 let ident_span = path.last().map_or(span, |ident| ident.ident.span);
456 let mut candidates = self
458 .lookup_import_candidates(ident, ns, &self.parent_scope, is_expected)
460 .filter(|ImportSuggestion { did, .. }| {
461 match (did, res.and_then(|res| res.opt_def_id())) {
462 (Some(suggestion_did), Some(actual_did)) => *suggestion_did != actual_did,
466 .collect::<Vec<_>>();
467 let crate_def_id = CRATE_DEF_ID.to_def_id();
468 // Try to filter out intrinsics candidates, as long as we have
469 // some other candidates to suggest.
470 let intrinsic_candidates: Vec<_> = candidates
471 .drain_filter(|sugg| {
472 let path = path_names_to_string(&sugg.path);
473 path.starts_with("core::intrinsics::") || path.starts_with("std::intrinsics::")
476 if candidates.is_empty() {
477 // Put them back if we have no more candidates to suggest...
478 candidates.extend(intrinsic_candidates);
480 if candidates.is_empty() && is_expected(Res::Def(DefKind::Enum, crate_def_id)) {
481 let mut enum_candidates: Vec<_> = self
483 .lookup_import_candidates(ident, ns, &self.parent_scope, is_enum_variant)
485 .map(|suggestion| import_candidate_to_enum_paths(&suggestion))
486 .filter(|(_, enum_ty_path)| !enum_ty_path.starts_with("std::prelude::"))
488 if !enum_candidates.is_empty() {
489 if let (PathSource::Type, Some(span)) =
490 (source, self.diagnostic_metadata.current_type_ascription.last())
496 .type_ascription_path_suggestions
500 // Already reported this issue on the lhs of the type ascription.
501 err.downgrade_to_delayed_bug();
502 return (true, candidates);
506 enum_candidates.sort();
508 // Contextualize for E0412 "cannot find type", but don't belabor the point
509 // (that it's a variant) for E0573 "expected type, found variant".
510 let preamble = if res.is_none() {
511 let others = match enum_candidates.len() {
513 2 => " and 1 other".to_owned(),
514 n => format!(" and {} others", n),
516 format!("there is an enum variant `{}`{}; ", enum_candidates[0].0, others)
520 let msg = format!("{}try using the variant's enum", preamble);
522 err.span_suggestions(
525 enum_candidates.into_iter().map(|(_variant_path, enum_ty_path)| enum_ty_path),
526 Applicability::MachineApplicable,
531 // Try Levenshtein algorithm.
533 self.lookup_typo_candidate(path, source.namespace(), is_expected).to_opt_suggestion();
534 if path.len() == 1 && self.self_type_is_available() {
535 if let Some(candidate) =
536 self.lookup_assoc_candidate(ident, ns, is_expected, source.is_call())
538 let self_is_available = self.self_value_is_available(path[0].ident.span);
540 AssocSuggestion::Field => {
541 if self_is_available {
544 "you might have meant to use the available field",
545 format!("self.{path_str}"),
546 Applicability::MachineApplicable,
549 err.span_label(span, "a field by this name exists in `Self`");
552 AssocSuggestion::MethodWithSelf { called } if self_is_available => {
553 let msg = if called {
554 "you might have meant to call the method"
556 "you might have meant to refer to the method"
561 format!("self.{path_str}"),
562 Applicability::MachineApplicable,
565 AssocSuggestion::MethodWithSelf { .. }
566 | AssocSuggestion::AssocFn { .. }
567 | AssocSuggestion::AssocConst
568 | AssocSuggestion::AssocType => {
571 &format!("you might have meant to {}", candidate.action()),
572 format!("Self::{path_str}"),
573 Applicability::MachineApplicable,
577 self.r.add_typo_suggestion(err, typo_sugg, ident_span);
578 return (true, candidates);
581 // If the first argument in call is `self` suggest calling a method.
582 if let Some((call_span, args_span)) = self.call_has_self_arg(source) {
583 let mut args_snippet = String::new();
584 if let Some(args_span) = args_span {
585 if let Ok(snippet) = self.r.session.source_map().span_to_snippet(args_span) {
586 args_snippet = snippet;
592 &format!("try calling `{ident}` as a method"),
593 format!("self.{path_str}({args_snippet})"),
594 Applicability::MachineApplicable,
596 return (true, candidates);
600 // Try context-dependent help if relaxed lookup didn't work.
601 if let Some(res) = res {
602 if self.smart_resolve_context_dependent_help(
608 &base_error.fallback_label,
610 // We do this to avoid losing a secondary span when we override the main error span.
611 self.r.add_typo_suggestion(err, typo_sugg, ident_span);
612 return (true, candidates);
615 return (false, candidates);
618 fn suggest_trait_and_bounds(
620 err: &mut Diagnostic,
621 source: PathSource<'_>,
624 base_error: &BaseError,
627 base_error.span.from_expansion() && base_error.span.desugaring_kind().is_none();
628 let mut fallback = false;
631 PathSource::Trait(AliasPossibility::Maybe),
632 Some(Res::Def(DefKind::Struct | DefKind::Enum | DefKind::Union, _)),
634 ) = (source, res, is_macro)
636 if let Some(bounds @ [_, .., _]) = self.diagnostic_metadata.current_trait_object {
638 let spans: Vec<Span> = bounds
640 .map(|bound| bound.span())
641 .filter(|&sp| sp != base_error.span)
644 let start_span = bounds[0].span();
645 // `end_span` is the end of the poly trait ref (Foo + 'baz + Bar><)
646 let end_span = bounds.last().unwrap().span();
647 // `last_bound_span` is the last bound of the poly trait ref (Foo + >'baz< + Bar)
648 let last_bound_span = spans.last().cloned().unwrap();
649 let mut multi_span: MultiSpan = spans.clone().into();
651 let msg = if sp == last_bound_span {
653 "...because of {these} bound{s}",
654 these = pluralize!("this", bounds.len() - 1),
655 s = pluralize!(bounds.len() - 1),
660 multi_span.push_span_label(sp, msg);
662 multi_span.push_span_label(base_error.span, "expected this type to be a trait...");
665 "`+` is used to constrain a \"trait object\" type with lifetimes or \
666 auto-traits; structs and enums can't be bound in that way",
668 if bounds.iter().all(|bound| match bound {
669 ast::GenericBound::Outlives(_) => true,
670 ast::GenericBound::Trait(tr, _) => tr.span == base_error.span,
672 let mut sugg = vec![];
673 if base_error.span != start_span {
674 sugg.push((start_span.until(base_error.span), String::new()));
676 if base_error.span != end_span {
677 sugg.push((base_error.span.shrink_to_hi().to(end_span), String::new()));
680 err.multipart_suggestion(
681 "if you meant to use a type and not a trait here, remove the bounds",
683 Applicability::MaybeIncorrect,
689 fallback |= self.restrict_assoc_type_in_where_clause(span, err);
695 err: &mut Diagnostic,
696 source: PathSource<'_>,
699 base_error: &BaseError,
701 let is_expected = &|res| source.is_expected(res);
702 let ident_span = path.last().map_or(span, |ident| ident.ident.span);
703 let typo_sugg = self.lookup_typo_candidate(path, source.namespace(), is_expected);
704 let is_in_same_file = &|sp1, sp2| {
705 let source_map = self.r.session.source_map();
706 let file1 = source_map.span_to_filename(sp1);
707 let file2 = source_map.span_to_filename(sp2);
710 // print 'you might have meant' if the candidate is (1) is a shadowed name with
711 // accessible definition and (2) either defined in the same crate as the typo
712 // (could be in a different file) or introduced in the same file as the typo
713 // (could belong to a different crate)
714 if let TypoCandidate::Shadowed(res, Some(sugg_span)) = typo_sugg
717 .map_or(false, |id| id.is_local() || is_in_same_file(span, sugg_span))
721 format!("you might have meant to refer to this {}", res.descr()),
725 let mut fallback = false;
726 let typo_sugg = typo_sugg.to_opt_suggestion();
727 if !self.r.add_typo_suggestion(err, typo_sugg, ident_span) {
729 match self.diagnostic_metadata.current_let_binding {
730 Some((pat_sp, Some(ty_sp), None))
731 if ty_sp.contains(base_error.span) && base_error.could_be_expr =>
733 err.span_suggestion_short(
734 pat_sp.between(ty_sp),
735 "use `=` if you meant to assign",
737 Applicability::MaybeIncorrect,
743 // If the trait has a single item (which wasn't matched by Levenshtein), suggest it
744 let suggestion = self.get_single_associated_item(&path, &source, is_expected);
745 if !self.r.add_typo_suggestion(err, suggestion, ident_span) {
746 fallback = !self.let_binding_suggestion(err, ident_span);
752 fn err_code_special_cases(
754 err: &mut Diagnostic,
755 source: PathSource<'_>,
759 if let Some(err_code) = &err.code {
760 if err_code == &rustc_errors::error_code!(E0425) {
761 for label_rib in &self.label_ribs {
762 for (label_ident, node_id) in &label_rib.bindings {
763 let ident = path.last().unwrap().ident;
764 if format!("'{}", ident) == label_ident.to_string() {
765 err.span_label(label_ident.span, "a label with a similar name exists");
766 if let PathSource::Expr(Some(Expr {
767 kind: ExprKind::Break(None, Some(_)),
773 "use the similarly named label",
775 Applicability::MaybeIncorrect,
777 // Do not lint against unused label when we suggest them.
778 self.diagnostic_metadata.unused_labels.remove(node_id);
783 } else if err_code == &rustc_errors::error_code!(E0412) {
784 if let Some(correct) = Self::likely_rust_type(path) {
787 "perhaps you intended to use this type",
789 Applicability::MaybeIncorrect,
796 /// Emit special messages for unresolved `Self` and `self`.
799 err: &mut Diagnostic,
800 source: PathSource<'_>,
804 if !is_self_type(path, source.namespace()) {
807 err.code(rustc_errors::error_code!(E0411));
808 err.span_label(span, "`Self` is only available in impls, traits, and type definitions");
809 if let Some(item_kind) = self.diagnostic_metadata.current_item {
810 if !item_kind.ident.span.is_dummy() {
812 item_kind.ident.span,
814 "`Self` not allowed in {} {}",
815 item_kind.kind.article(),
816 item_kind.kind.descr()
824 fn suggest_self_value(
826 err: &mut Diagnostic,
827 source: PathSource<'_>,
831 if !is_self_value(path, source.namespace()) {
835 debug!("smart_resolve_path_fragment: E0424, source={:?}", source);
836 err.code(rustc_errors::error_code!(E0424));
841 "`self` value is a keyword and may not be bound to variables or shadowed"
843 _ => "`self` value is a keyword only available in methods with a `self` parameter",
846 let is_assoc_fn = self.self_type_is_available();
847 if let Some((fn_kind, span)) = &self.diagnostic_metadata.current_function {
848 // The current function has a `self' parameter, but we were unable to resolve
849 // a reference to `self`. This can only happen if the `self` identifier we
850 // are resolving came from a different hygiene context.
851 if fn_kind.decl().inputs.get(0).map_or(false, |p| p.is_self()) {
852 err.span_label(*span, "this function has a `self` parameter, but a macro invocation can only access identifiers it receives from parameters");
854 let doesnt = if is_assoc_fn {
855 let (span, sugg) = fn_kind
859 .map(|p| (p.span.shrink_to_lo(), "&self, "))
861 // Try to look for the "(" after the function name, if possible.
862 // This avoids placing the suggestion into the visibility specifier.
865 .map_or(*span, |ident| span.with_lo(ident.span.hi()));
870 .span_through_char(span, '(')
875 err.span_suggestion_verbose(
877 "add a `self` receiver parameter to make the associated `fn` a method",
879 Applicability::MaybeIncorrect,
885 if let Some(ident) = fn_kind.ident() {
888 &format!("this function {} have a `self` parameter", doesnt),
892 } else if let Some(item_kind) = self.diagnostic_metadata.current_item {
894 item_kind.ident.span,
896 "`self` not allowed in {} {}",
897 item_kind.kind.article(),
898 item_kind.kind.descr()
905 fn suggest_swapping_misplaced_self_ty_and_trait(
907 err: &mut Diagnostic,
908 source: PathSource<'_>,
912 if let Some((trait_ref, self_ty)) =
913 self.diagnostic_metadata.currently_processing_impl_trait.clone()
914 && let TyKind::Path(_, self_ty_path) = &self_ty.kind
915 && let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
916 self.resolve_path(&Segment::from_path(self_ty_path), Some(TypeNS), None)
917 && let ModuleKind::Def(DefKind::Trait, ..) = module.kind
918 && trait_ref.path.span == span
919 && let PathSource::Trait(_) = source
920 && let Some(Res::Def(DefKind::Struct | DefKind::Enum | DefKind::Union, _)) = res
921 && let Ok(self_ty_str) =
922 self.r.session.source_map().span_to_snippet(self_ty.span)
923 && let Ok(trait_ref_str) =
924 self.r.session.source_map().span_to_snippet(trait_ref.path.span)
926 err.multipart_suggestion(
927 "`impl` items mention the trait being implemented first and the type it is being implemented for second",
928 vec![(trait_ref.path.span, self_ty_str), (self_ty.span, trait_ref_str)],
929 Applicability::MaybeIncorrect,
934 fn suggest_bare_struct_literal(&mut self, err: &mut Diagnostic) {
935 if let Some(span) = self.diagnostic_metadata.current_block_could_be_bare_struct_literal {
936 err.multipart_suggestion(
937 "you might have meant to write a `struct` literal",
939 (span.shrink_to_lo(), "{ SomeStruct ".to_string()),
940 (span.shrink_to_hi(), "}".to_string()),
942 Applicability::HasPlaceholders,
947 fn suggest_pattern_match_with_let(
949 err: &mut Diagnostic,
950 source: PathSource<'_>,
953 if let PathSource::Expr(_) = source &&
956 kind: ExprKind::Assign(lhs, _, _),
958 }) = self.diagnostic_metadata.in_if_condition {
959 // Icky heuristic so we don't suggest:
960 // `if (i + 2) = 2` => `if let (i + 2) = 2` (approximately pattern)
961 // `if 2 = i` => `if let 2 = i` (lhs needs to contain error span)
962 if lhs.is_approximately_pattern() && lhs.span.contains(span) {
963 err.span_suggestion_verbose(
964 expr_span.shrink_to_lo(),
965 "you might have meant to use pattern matching",
967 Applicability::MaybeIncorrect,
975 fn get_single_associated_item(
978 source: &PathSource<'_>,
979 filter_fn: &impl Fn(Res) -> bool,
980 ) -> Option<TypoSuggestion> {
981 if let crate::PathSource::TraitItem(_) = source {
982 let mod_path = &path[..path.len() - 1];
983 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
984 self.resolve_path(mod_path, None, None)
986 let resolutions = self.r.resolutions(module).borrow();
987 let targets: Vec<_> =
990 .filter_map(|(key, resolution)| {
991 resolution.borrow().binding.map(|binding| binding.res()).and_then(
992 |res| if filter_fn(res) { Some((key, res)) } else { None },
996 if targets.len() == 1 {
997 let target = targets[0];
998 return Some(TypoSuggestion::single_item_from_ident(target.0.ident, target.1));
1005 /// Given `where <T as Bar>::Baz: String`, suggest `where T: Bar<Baz = String>`.
1006 fn restrict_assoc_type_in_where_clause(&mut self, span: Span, err: &mut Diagnostic) -> bool {
1007 // Detect that we are actually in a `where` predicate.
1008 let (bounded_ty, bounds, where_span) =
1009 if let Some(ast::WherePredicate::BoundPredicate(ast::WhereBoundPredicate {
1011 bound_generic_params,
1014 })) = self.diagnostic_metadata.current_where_predicate
1016 if !bound_generic_params.is_empty() {
1019 (bounded_ty, bounds, span)
1024 // Confirm that the target is an associated type.
1025 let (ty, position, path) = if let ast::TyKind::Path(Some(qself), path) = &bounded_ty.kind {
1026 // use this to verify that ident is a type param.
1027 let Some(partial_res) = self.r.partial_res_map.get(&bounded_ty.id) else {
1031 partial_res.full_res(),
1032 Some(hir::def::Res::Def(hir::def::DefKind::AssocTy, _))
1036 (&qself.ty, qself.position, path)
1041 let peeled_ty = ty.peel_refs();
1042 if let ast::TyKind::Path(None, type_param_path) = &peeled_ty.kind {
1043 // Confirm that the `SelfTy` is a type parameter.
1044 let Some(partial_res) = self.r.partial_res_map.get(&peeled_ty.id) else {
1048 partial_res.full_res(),
1049 Some(hir::def::Res::Def(hir::def::DefKind::TyParam, _))
1054 [ast::PathSegment { ident: constrain_ident, args: None, .. }],
1055 [ast::GenericBound::Trait(poly_trait_ref, ast::TraitBoundModifier::None)],
1056 ) = (&type_param_path.segments[..], &bounds[..])
1058 if let [ast::PathSegment { ident, args: None, .. }] =
1059 &poly_trait_ref.trait_ref.path.segments[..]
1061 if ident.span == span {
1062 err.span_suggestion_verbose(
1064 &format!("constrain the associated type to `{}`", ident),
1070 .span_to_snippet(ty.span) // Account for `<&'a T as Foo>::Bar`.
1071 .unwrap_or_else(|_| constrain_ident.to_string()),
1072 path.segments[..position]
1074 .map(|segment| path_segment_to_string(segment))
1075 .collect::<Vec<_>>()
1077 path.segments[position..]
1079 .map(|segment| path_segment_to_string(segment))
1080 .collect::<Vec<_>>()
1084 Applicability::MaybeIncorrect,
1094 /// Check if the source is call expression and the first argument is `self`. If true,
1095 /// return the span of whole call and the span for all arguments expect the first one (`self`).
1096 fn call_has_self_arg(&self, source: PathSource<'_>) -> Option<(Span, Option<Span>)> {
1097 let mut has_self_arg = None;
1098 if let PathSource::Expr(Some(parent)) = source {
1099 match &parent.kind {
1100 ExprKind::Call(_, args) if !args.is_empty() => {
1101 let mut expr_kind = &args[0].kind;
1104 ExprKind::Path(_, arg_name) if arg_name.segments.len() == 1 => {
1105 if arg_name.segments[0].ident.name == kw::SelfLower {
1106 let call_span = parent.span;
1107 let tail_args_span = if args.len() > 1 {
1110 args.last().unwrap().span.hi(),
1117 has_self_arg = Some((call_span, tail_args_span));
1121 ExprKind::AddrOf(_, _, expr) => expr_kind = &expr.kind,
1132 fn followed_by_brace(&self, span: Span) -> (bool, Option<Span>) {
1133 // HACK(estebank): find a better way to figure out that this was a
1134 // parser issue where a struct literal is being used on an expression
1135 // where a brace being opened means a block is being started. Look
1136 // ahead for the next text to see if `span` is followed by a `{`.
1137 let sm = self.r.session.source_map();
1138 let sp = sm.span_look_ahead(span, None, Some(50));
1139 let followed_by_brace = matches!(sm.span_to_snippet(sp), Ok(ref snippet) if snippet == "{");
1140 // In case this could be a struct literal that needs to be surrounded
1141 // by parentheses, find the appropriate span.
1142 let closing_span = sm.span_look_ahead(span, Some("}"), Some(50));
1143 let closing_brace: Option<Span> = sm
1144 .span_to_snippet(closing_span)
1145 .map_or(None, |s| if s == "}" { Some(span.to(closing_span)) } else { None });
1146 (followed_by_brace, closing_brace)
1149 /// Provides context-dependent help for errors reported by the `smart_resolve_path_fragment`
1151 /// Returns `true` if able to provide context-dependent help.
1152 fn smart_resolve_context_dependent_help(
1154 err: &mut Diagnostic,
1156 source: PathSource<'_>,
1159 fallback_label: &str,
1161 let ns = source.namespace();
1162 let is_expected = &|res| source.is_expected(res);
1164 let path_sep = |err: &mut Diagnostic, expr: &Expr, kind: DefKind| {
1165 const MESSAGE: &str = "use the path separator to refer to an item";
1167 let (lhs_span, rhs_span) = match &expr.kind {
1168 ExprKind::Field(base, ident) => (base.span, ident.span),
1169 ExprKind::MethodCall(box MethodCall { receiver, span, .. }) => {
1170 (receiver.span, *span)
1175 if lhs_span.eq_ctxt(rhs_span) {
1176 err.span_suggestion(
1177 lhs_span.between(rhs_span),
1180 Applicability::MaybeIncorrect,
1183 } else if kind == DefKind::Struct
1184 && let Some(lhs_source_span) = lhs_span.find_ancestor_inside(expr.span)
1185 && let Ok(snippet) = self.r.session.source_map().span_to_snippet(lhs_source_span)
1187 // The LHS is a type that originates from a macro call.
1188 // We have to add angle brackets around it.
1190 err.span_suggestion_verbose(
1191 lhs_source_span.until(rhs_span),
1193 format!("<{snippet}>::"),
1194 Applicability::MaybeIncorrect,
1198 // Either we were unable to obtain the source span / the snippet or
1199 // the LHS originates from a macro call and it is not a type and thus
1200 // there is no way to replace `.` with `::` and still somehow suggest
1207 let find_span = |source: &PathSource<'_>, err: &mut Diagnostic| {
1209 PathSource::Expr(Some(Expr { span, kind: ExprKind::Call(_, _), .. }))
1210 | PathSource::TupleStruct(span, _) => {
1211 // We want the main underline to cover the suggested code as well for
1213 err.set_span(*span);
1220 let mut bad_struct_syntax_suggestion = |def_id: DefId| {
1221 let (followed_by_brace, closing_brace) = self.followed_by_brace(span);
1224 PathSource::Expr(Some(
1225 parent @ Expr { kind: ExprKind::Field(..) | ExprKind::MethodCall(..), .. },
1226 )) if path_sep(err, &parent, DefKind::Struct) => {}
1232 | ExprKind::Binary(..)
1233 | ExprKind::Unary(..)
1235 | ExprKind::While(..)
1236 | ExprKind::ForLoop(..)
1237 | ExprKind::Match(..),
1240 ) if followed_by_brace => {
1241 if let Some(sp) = closing_brace {
1242 err.span_label(span, fallback_label);
1243 err.multipart_suggestion(
1244 "surround the struct literal with parentheses",
1246 (sp.shrink_to_lo(), "(".to_string()),
1247 (sp.shrink_to_hi(), ")".to_string()),
1249 Applicability::MaybeIncorrect,
1253 span, // Note the parentheses surrounding the suggestion below
1255 "you might want to surround a struct literal with parentheses: \
1256 `({} {{ /* fields */ }})`?",
1262 PathSource::Expr(_) | PathSource::TupleStruct(..) | PathSource::Pat => {
1263 let span = find_span(&source, err);
1264 if let Some(span) = self.def_span(def_id) {
1265 err.span_label(span, &format!("`{}` defined here", path_str));
1267 let (tail, descr, applicability) = match source {
1268 PathSource::Pat | PathSource::TupleStruct(..) => {
1269 ("", "pattern", Applicability::MachineApplicable)
1271 _ => (": val", "literal", Applicability::HasPlaceholders),
1273 let (fields, applicability) = match self.r.field_names.get(&def_id) {
1277 .map(|f| format!("{}{}", f.node, tail))
1278 .collect::<Vec<String>>()
1282 None => ("/* fields */".to_string(), Applicability::HasPlaceholders),
1284 let pad = match self.r.field_names.get(&def_id) {
1285 Some(fields) if fields.is_empty() => "",
1288 err.span_suggestion(
1290 &format!("use struct {} syntax instead", descr),
1291 format!("{path_str} {{{pad}{fields}{pad}}}"),
1296 err.span_label(span, fallback_label);
1301 match (res, source) {
1303 Res::Def(DefKind::Macro(MacroKind::Bang), _),
1304 PathSource::Expr(Some(Expr {
1305 kind: ExprKind::Index(..) | ExprKind::Call(..), ..
1307 | PathSource::Struct,
1309 err.span_label(span, fallback_label);
1310 err.span_suggestion_verbose(
1311 span.shrink_to_hi(),
1312 "use `!` to invoke the macro",
1314 Applicability::MaybeIncorrect,
1316 if path_str == "try" && span.rust_2015() {
1317 err.note("if you want the `try` keyword, you need Rust 2018 or later");
1320 (Res::Def(DefKind::Macro(MacroKind::Bang), _), _) => {
1321 err.span_label(span, fallback_label);
1323 (Res::Def(DefKind::TyAlias, def_id), PathSource::Trait(_)) => {
1324 err.span_label(span, "type aliases cannot be used as traits");
1325 if self.r.session.is_nightly_build() {
1326 let msg = "you might have meant to use `#![feature(trait_alias)]` instead of a \
1328 if let Some(span) = self.def_span(def_id) {
1329 if let Ok(snip) = self.r.session.source_map().span_to_snippet(span) {
1330 // The span contains a type alias so we should be able to
1331 // replace `type` with `trait`.
1332 let snip = snip.replacen("type", "trait", 1);
1333 err.span_suggestion(span, msg, snip, Applicability::MaybeIncorrect);
1335 err.span_help(span, msg);
1343 Res::Def(kind @ (DefKind::Mod | DefKind::Trait), _),
1344 PathSource::Expr(Some(parent)),
1346 if !path_sep(err, &parent, kind) {
1351 Res::Def(DefKind::Enum, def_id),
1352 PathSource::TupleStruct(..) | PathSource::Expr(..),
1355 .diagnostic_metadata
1356 .current_type_ascription
1362 .type_ascription_path_suggestions
1368 err.downgrade_to_delayed_bug();
1369 // We already suggested changing `:` into `::` during parsing.
1373 self.suggest_using_enum_variant(err, source, def_id, span);
1375 (Res::Def(DefKind::Struct, def_id), source) if ns == ValueNS => {
1376 let (ctor_def, ctor_vis, fields) =
1377 if let Some(struct_ctor) = self.r.struct_constructors.get(&def_id).cloned() {
1378 if let PathSource::Expr(Some(parent)) = source {
1379 if let ExprKind::Field(..) | ExprKind::MethodCall(..) = parent.kind {
1380 bad_struct_syntax_suggestion(def_id);
1386 bad_struct_syntax_suggestion(def_id);
1390 let is_accessible = self.r.is_accessible_from(ctor_vis, self.parent_scope.module);
1391 if !is_expected(ctor_def) || is_accessible {
1395 let field_spans = match source {
1396 // e.g. `if let Enum::TupleVariant(field1, field2) = _`
1397 PathSource::TupleStruct(_, pattern_spans) => {
1398 err.set_primary_message(
1399 "cannot match against a tuple struct which contains private fields",
1402 // Use spans of the tuple struct pattern.
1403 Some(Vec::from(pattern_spans))
1405 // e.g. `let _ = Enum::TupleVariant(field1, field2);`
1406 _ if source.is_call() => {
1407 err.set_primary_message(
1408 "cannot initialize a tuple struct which contains private fields",
1411 // Use spans of the tuple struct definition.
1415 .map(|fields| fields.iter().map(|f| f.span).collect::<Vec<_>>())
1420 if let Some(spans) =
1421 field_spans.filter(|spans| spans.len() > 0 && fields.len() == spans.len())
1423 let non_visible_spans: Vec<Span> = iter::zip(&fields, &spans)
1424 .filter(|(vis, _)| {
1425 !self.r.is_accessible_from(**vis, self.parent_scope.module)
1427 .map(|(_, span)| *span)
1430 if non_visible_spans.len() > 0 {
1431 let mut m: MultiSpan = non_visible_spans.clone().into();
1434 .for_each(|s| m.push_span_label(s, "private field"));
1435 err.span_note(m, "constructor is not visible here due to private fields");
1441 err.span_label(span, "constructor is not visible here due to private fields");
1445 DefKind::Union | DefKind::Variant | DefKind::Ctor(_, CtorKind::Fictive),
1449 ) if ns == ValueNS => {
1450 bad_struct_syntax_suggestion(def_id);
1452 (Res::Def(DefKind::Ctor(_, CtorKind::Const), def_id), _) if ns == ValueNS => {
1454 PathSource::Expr(_) | PathSource::TupleStruct(..) | PathSource::Pat => {
1455 let span = find_span(&source, err);
1456 if let Some(span) = self.def_span(def_id) {
1457 err.span_label(span, &format!("`{}` defined here", path_str));
1459 err.span_suggestion(
1461 "use this syntax instead",
1463 Applicability::MaybeIncorrect,
1469 (Res::Def(DefKind::Ctor(_, CtorKind::Fn), def_id), _) if ns == ValueNS => {
1470 if let Some(span) = self.def_span(def_id) {
1471 err.span_label(span, &format!("`{}` defined here", path_str));
1473 let fields = self.r.field_names.get(&def_id).map_or_else(
1474 || "/* fields */".to_string(),
1475 |fields| vec!["_"; fields.len()].join(", "),
1477 err.span_suggestion(
1479 "use the tuple variant pattern syntax instead",
1480 format!("{}({})", path_str, fields),
1481 Applicability::HasPlaceholders,
1484 (Res::SelfTyParam { .. } | Res::SelfTyAlias { .. }, _) if ns == ValueNS => {
1485 err.span_label(span, fallback_label);
1486 err.note("can't use `Self` as a constructor, you must use the implemented struct");
1488 (Res::Def(DefKind::TyAlias | DefKind::AssocTy, _), _) if ns == ValueNS => {
1489 err.note("can't use a type alias as a constructor");
1496 /// Given the target `ident` and `kind`, search for the similarly named associated item
1497 /// in `self.current_trait_ref`.
1498 pub(crate) fn find_similarly_named_assoc_item(
1501 kind: &AssocItemKind,
1502 ) -> Option<Symbol> {
1503 let (module, _) = self.current_trait_ref.as_ref()?;
1504 if ident == kw::Underscore {
1505 // We do nothing for `_`.
1509 let resolutions = self.r.resolutions(module);
1510 let targets = resolutions
1513 .filter_map(|(key, res)| res.borrow().binding.map(|binding| (key, binding.res())))
1514 .filter(|(_, res)| match (kind, res) {
1515 (AssocItemKind::Const(..), Res::Def(DefKind::AssocConst, _)) => true,
1516 (AssocItemKind::Fn(_), Res::Def(DefKind::AssocFn, _)) => true,
1517 (AssocItemKind::Type(..), Res::Def(DefKind::AssocTy, _)) => true,
1520 .map(|(key, _)| key.ident.name)
1521 .collect::<Vec<_>>();
1523 find_best_match_for_name(&targets, ident, None)
1526 fn lookup_assoc_candidate<FilterFn>(
1530 filter_fn: FilterFn,
1532 ) -> Option<AssocSuggestion>
1534 FilterFn: Fn(Res) -> bool,
1536 fn extract_node_id(t: &Ty) -> Option<NodeId> {
1538 TyKind::Path(None, _) => Some(t.id),
1539 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
1540 // This doesn't handle the remaining `Ty` variants as they are not
1541 // that commonly the self_type, it might be interesting to provide
1542 // support for those in future.
1546 // Fields are generally expected in the same contexts as locals.
1547 if filter_fn(Res::Local(ast::DUMMY_NODE_ID)) {
1548 if let Some(node_id) =
1549 self.diagnostic_metadata.current_self_type.as_ref().and_then(extract_node_id)
1551 // Look for a field with the same name in the current self_type.
1552 if let Some(resolution) = self.r.partial_res_map.get(&node_id) {
1553 if let Some(Res::Def(DefKind::Struct | DefKind::Union, did)) =
1554 resolution.full_res()
1556 if let Some(field_names) = self.r.field_names.get(&did) {
1557 if field_names.iter().any(|&field_name| ident.name == field_name.node) {
1558 return Some(AssocSuggestion::Field);
1566 if let Some(items) = self.diagnostic_metadata.current_trait_assoc_items {
1567 for assoc_item in items {
1568 if assoc_item.ident == ident {
1569 return Some(match &assoc_item.kind {
1570 ast::AssocItemKind::Const(..) => AssocSuggestion::AssocConst,
1571 ast::AssocItemKind::Fn(box ast::Fn { sig, .. }) if sig.decl.has_self() => {
1572 AssocSuggestion::MethodWithSelf { called }
1574 ast::AssocItemKind::Fn(..) => AssocSuggestion::AssocFn { called },
1575 ast::AssocItemKind::Type(..) => AssocSuggestion::AssocType,
1576 ast::AssocItemKind::MacCall(_) => continue,
1582 // Look for associated items in the current trait.
1583 if let Some((module, _)) = self.current_trait_ref {
1584 if let Ok(binding) = self.r.maybe_resolve_ident_in_module(
1585 ModuleOrUniformRoot::Module(module),
1590 let res = binding.res();
1592 if self.r.has_self.contains(&res.def_id()) {
1593 return Some(AssocSuggestion::MethodWithSelf { called });
1596 Res::Def(DefKind::AssocFn, _) => {
1597 return Some(AssocSuggestion::AssocFn { called });
1599 Res::Def(DefKind::AssocConst, _) => {
1600 return Some(AssocSuggestion::AssocConst);
1602 Res::Def(DefKind::AssocTy, _) => {
1603 return Some(AssocSuggestion::AssocType);
1615 fn lookup_typo_candidate(
1619 filter_fn: &impl Fn(Res) -> bool,
1620 ) -> TypoCandidate {
1621 let mut names = Vec::new();
1622 if path.len() == 1 {
1623 let mut ctxt = path.last().unwrap().ident.span.ctxt();
1625 // Search in lexical scope.
1626 // Walk backwards up the ribs in scope and collect candidates.
1627 for rib in self.ribs[ns].iter().rev() {
1628 let rib_ctxt = if rib.kind.contains_params() {
1629 ctxt.normalize_to_macros_2_0()
1631 ctxt.normalize_to_macro_rules()
1634 // Locals and type parameters
1635 for (ident, &res) in &rib.bindings {
1636 if filter_fn(res) && ident.span.ctxt() == rib_ctxt {
1637 names.push(TypoSuggestion::typo_from_ident(*ident, res));
1641 if let RibKind::MacroDefinition(def) = rib.kind && def == self.r.macro_def(ctxt) {
1642 // If an invocation of this macro created `ident`, give up on `ident`
1643 // and switch to `ident`'s source from the macro definition.
1649 if let RibKind::ModuleRibKind(module) = rib.kind {
1650 // Items from this module
1651 self.r.add_module_candidates(module, &mut names, &filter_fn, Some(ctxt));
1653 if let ModuleKind::Block = module.kind {
1654 // We can see through blocks
1656 // Items from the prelude
1657 if !module.no_implicit_prelude {
1658 let extern_prelude = self.r.extern_prelude.clone();
1659 names.extend(extern_prelude.iter().flat_map(|(ident, _)| {
1660 self.r.crate_loader.maybe_process_path_extern(ident.name).and_then(
1663 Res::Def(DefKind::Mod, crate_id.as_def_id());
1665 if filter_fn(crate_mod) {
1666 Some(TypoSuggestion::typo_from_ident(*ident, crate_mod))
1674 if let Some(prelude) = self.r.prelude {
1675 self.r.add_module_candidates(prelude, &mut names, &filter_fn, None);
1682 // Add primitive types to the mix
1683 if filter_fn(Res::PrimTy(PrimTy::Bool)) {
1684 names.extend(PrimTy::ALL.iter().map(|prim_ty| {
1685 TypoSuggestion::typo_from_name(prim_ty.name(), Res::PrimTy(*prim_ty))
1689 // Search in module.
1690 let mod_path = &path[..path.len() - 1];
1691 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
1692 self.resolve_path(mod_path, Some(TypeNS), None)
1694 self.r.add_module_candidates(module, &mut names, &filter_fn, None);
1698 let name = path[path.len() - 1].ident.name;
1699 // Make sure error reporting is deterministic.
1700 names.sort_by(|a, b| a.candidate.as_str().partial_cmp(b.candidate.as_str()).unwrap());
1702 match find_best_match_for_name(
1703 &names.iter().map(|suggestion| suggestion.candidate).collect::<Vec<Symbol>>(),
1708 let Some(sugg) = names.into_iter().find(|suggestion| suggestion.candidate == found) else {
1709 return TypoCandidate::None;
1712 TypoCandidate::Shadowed(sugg.res, sugg.span)
1714 TypoCandidate::Typo(sugg)
1717 _ => TypoCandidate::None,
1721 // Returns the name of the Rust type approximately corresponding to
1722 // a type name in another programming language.
1723 fn likely_rust_type(path: &[Segment]) -> Option<Symbol> {
1724 let name = path[path.len() - 1].ident.as_str();
1725 // Common Java types
1727 "byte" => sym::u8, // In Java, bytes are signed, but in practice one almost always wants unsigned bytes.
1728 "short" => sym::i16,
1729 "Bool" => sym::bool,
1730 "Boolean" => sym::bool,
1731 "boolean" => sym::bool,
1734 "float" => sym::f32,
1735 "double" => sym::f64,
1740 /// Only used in a specific case of type ascription suggestions
1741 fn get_colon_suggestion_span(&self, start: Span) -> Span {
1742 let sm = self.r.session.source_map();
1743 start.to(sm.next_point(start))
1746 fn type_ascription_suggestion(&self, err: &mut Diagnostic, base_span: Span) -> bool {
1747 let sm = self.r.session.source_map();
1748 let base_snippet = sm.span_to_snippet(base_span);
1749 if let Some(&sp) = self.diagnostic_metadata.current_type_ascription.last() {
1750 if let Ok(snippet) = sm.span_to_snippet(sp) {
1751 let len = snippet.trim_end().len() as u32;
1752 if snippet.trim() == ":" {
1754 sp.with_lo(sp.lo() + BytePos(len - 1)).with_hi(sp.lo() + BytePos(len));
1755 let mut show_label = true;
1756 if sm.is_multiline(sp) {
1757 err.span_suggestion_short(
1759 "maybe you meant to write `;` here",
1761 Applicability::MaybeIncorrect,
1764 let after_colon_sp =
1765 self.get_colon_suggestion_span(colon_sp.shrink_to_hi());
1766 if snippet.len() == 1 {
1768 err.span_suggestion(
1770 "maybe you meant to write a path separator here",
1772 Applicability::MaybeIncorrect,
1779 .type_ascription_path_suggestions
1783 err.downgrade_to_delayed_bug();
1786 if let Ok(base_snippet) = base_snippet {
1787 // Try to find an assignment
1788 let eq_span = sm.span_look_ahead(after_colon_sp, Some("="), Some(50));
1789 if let Ok(ref snippet) = sm.span_to_snippet(eq_span) && snippet == "=" {
1790 err.span_suggestion(
1792 "maybe you meant to write an assignment here",
1793 format!("let {}", base_snippet),
1794 Applicability::MaybeIncorrect,
1803 "expecting a type here because of type ascription",
1813 // try to give a suggestion for this pattern: `name = blah`, which is common in other languages
1814 // suggest `let name = blah` to introduce a new binding
1815 fn let_binding_suggestion(&mut self, err: &mut Diagnostic, ident_span: Span) -> bool {
1816 if let Some(Expr { kind: ExprKind::Assign(lhs, .. ), .. }) = self.diagnostic_metadata.in_assignment &&
1817 let ast::ExprKind::Path(None, _) = lhs.kind {
1818 if !ident_span.from_expansion() {
1819 err.span_suggestion_verbose(
1820 ident_span.shrink_to_lo(),
1821 "you might have meant to introduce a new binding",
1823 Applicability::MaybeIncorrect,
1831 fn find_module(&mut self, def_id: DefId) -> Option<(Module<'a>, ImportSuggestion)> {
1832 let mut result = None;
1833 let mut seen_modules = FxHashSet::default();
1834 let mut worklist = vec![(self.r.graph_root, Vec::new())];
1836 while let Some((in_module, path_segments)) = worklist.pop() {
1837 // abort if the module is already found
1838 if result.is_some() {
1842 in_module.for_each_child(self.r, |_, ident, _, name_binding| {
1843 // abort if the module is already found or if name_binding is private external
1844 if result.is_some() || !name_binding.vis.is_visible_locally() {
1847 if let Some(module) = name_binding.module() {
1849 let mut path_segments = path_segments.clone();
1850 path_segments.push(ast::PathSegment::from_ident(ident));
1851 let module_def_id = module.def_id();
1852 if module_def_id == def_id {
1854 Path { span: name_binding.span, segments: path_segments, tokens: None };
1866 // add the module to the lookup
1867 if seen_modules.insert(module_def_id) {
1868 worklist.push((module, path_segments));
1878 fn collect_enum_ctors(&mut self, def_id: DefId) -> Option<Vec<(Path, DefId, CtorKind)>> {
1879 self.find_module(def_id).map(|(enum_module, enum_import_suggestion)| {
1880 let mut variants = Vec::new();
1881 enum_module.for_each_child(self.r, |_, ident, _, name_binding| {
1882 if let Res::Def(DefKind::Ctor(CtorOf::Variant, kind), def_id) = name_binding.res() {
1883 let mut segms = enum_import_suggestion.path.segments.clone();
1884 segms.push(ast::PathSegment::from_ident(ident));
1885 let path = Path { span: name_binding.span, segments: segms, tokens: None };
1886 variants.push((path, def_id, kind));
1893 /// Adds a suggestion for using an enum's variant when an enum is used instead.
1894 fn suggest_using_enum_variant(
1896 err: &mut Diagnostic,
1897 source: PathSource<'_>,
1901 let Some(variants) = self.collect_enum_ctors(def_id) else {
1902 err.note("you might have meant to use one of the enum's variants");
1906 let suggest_only_tuple_variants =
1907 matches!(source, PathSource::TupleStruct(..)) || source.is_call();
1908 if suggest_only_tuple_variants {
1909 // Suggest only tuple variants regardless of whether they have fields and do not
1910 // suggest path with added parentheses.
1911 let suggestable_variants = variants
1913 .filter(|(.., kind)| *kind == CtorKind::Fn)
1914 .map(|(variant, ..)| path_names_to_string(variant))
1915 .collect::<Vec<_>>();
1917 let non_suggestable_variant_count = variants.len() - suggestable_variants.len();
1919 let source_msg = if source.is_call() {
1921 } else if matches!(source, PathSource::TupleStruct(..)) {
1927 if !suggestable_variants.is_empty() {
1928 let msg = if non_suggestable_variant_count == 0 && suggestable_variants.len() == 1 {
1929 format!("try {} the enum's variant", source_msg)
1931 format!("try {} one of the enum's variants", source_msg)
1934 err.span_suggestions(
1937 suggestable_variants,
1938 Applicability::MaybeIncorrect,
1942 // If the enum has no tuple variants..
1943 if non_suggestable_variant_count == variants.len() {
1944 err.help(&format!("the enum has no tuple variants {}", source_msg));
1947 // If there are also non-tuple variants..
1948 if non_suggestable_variant_count == 1 {
1950 "you might have meant {} the enum's non-tuple variant",
1953 } else if non_suggestable_variant_count >= 1 {
1955 "you might have meant {} one of the enum's non-tuple variants",
1960 let needs_placeholder = |def_id: DefId, kind: CtorKind| {
1961 let has_no_fields = self.r.field_names.get(&def_id).map_or(false, |f| f.is_empty());
1963 CtorKind::Const => false,
1964 CtorKind::Fn | CtorKind::Fictive if has_no_fields => false,
1969 let suggestable_variants = variants
1971 .filter(|(_, def_id, kind)| !needs_placeholder(*def_id, *kind))
1972 .map(|(variant, _, kind)| (path_names_to_string(variant), kind))
1973 .map(|(variant, kind)| match kind {
1974 CtorKind::Const => variant,
1975 CtorKind::Fn => format!("({}())", variant),
1976 CtorKind::Fictive => format!("({} {{}})", variant),
1978 .collect::<Vec<_>>();
1979 let no_suggestable_variant = suggestable_variants.is_empty();
1981 if !no_suggestable_variant {
1982 let msg = if suggestable_variants.len() == 1 {
1983 "you might have meant to use the following enum variant"
1985 "you might have meant to use one of the following enum variants"
1988 err.span_suggestions(
1991 suggestable_variants,
1992 Applicability::MaybeIncorrect,
1996 let suggestable_variants_with_placeholders = variants
1998 .filter(|(_, def_id, kind)| needs_placeholder(*def_id, *kind))
1999 .map(|(variant, _, kind)| (path_names_to_string(variant), kind))
2000 .filter_map(|(variant, kind)| match kind {
2001 CtorKind::Fn => Some(format!("({}(/* fields */))", variant)),
2002 CtorKind::Fictive => Some(format!("({} {{ /* fields */ }})", variant)),
2005 .collect::<Vec<_>>();
2007 if !suggestable_variants_with_placeholders.is_empty() {
2009 match (no_suggestable_variant, suggestable_variants_with_placeholders.len()) {
2010 (true, 1) => "the following enum variant is available",
2011 (true, _) => "the following enum variants are available",
2012 (false, 1) => "alternatively, the following enum variant is available",
2014 "alternatively, the following enum variants are also available"
2018 err.span_suggestions(
2021 suggestable_variants_with_placeholders,
2022 Applicability::HasPlaceholders,
2027 if def_id.is_local() {
2028 if let Some(span) = self.def_span(def_id) {
2029 err.span_note(span, "the enum is defined here");
2034 pub(crate) fn report_missing_type_error(
2037 ) -> Option<(Span, &'static str, String, Applicability)> {
2038 let (ident, span) = match path {
2039 [segment] if !segment.has_generic_args && segment.ident.name != kw::SelfUpper => {
2040 (segment.ident.to_string(), segment.ident.span)
2044 let mut iter = ident.chars().map(|c| c.is_uppercase());
2045 let single_uppercase_char =
2046 matches!(iter.next(), Some(true)) && matches!(iter.next(), None);
2047 if !self.diagnostic_metadata.currently_processing_generics && !single_uppercase_char {
2050 match (self.diagnostic_metadata.current_item, single_uppercase_char, self.diagnostic_metadata.currently_processing_generics) {
2051 (Some(Item { kind: ItemKind::Fn(..), ident, .. }), _, _) if ident.name == sym::main => {
2052 // Ignore `fn main()` as we don't want to suggest `fn main<T>()`
2057 kind @ ItemKind::Fn(..)
2058 | kind @ ItemKind::Enum(..)
2059 | kind @ ItemKind::Struct(..)
2060 | kind @ ItemKind::Union(..),
2065 // Without the 2nd `true`, we'd suggest `impl <T>` for `impl T` when a type `T` isn't found
2066 | (Some(Item { kind: kind @ ItemKind::Impl(..), .. }), true, true)
2067 | (Some(Item { kind, .. }), false, _) => {
2068 // Likely missing type parameter.
2069 if let Some(generics) = kind.generics() {
2070 if span.overlaps(generics.span) {
2071 // Avoid the following:
2072 // error[E0405]: cannot find trait `A` in this scope
2073 // --> $DIR/typo-suggestion-named-underscore.rs:CC:LL
2075 // L | fn foo<T: A>(x: T) {} // Shouldn't suggest underscore
2076 // | ^- help: you might be missing a type parameter: `, A`
2078 // | not found in this scope
2081 let msg = "you might be missing a type parameter";
2082 let (span, sugg) = if let [.., param] = &generics.params[..] {
2083 let span = if let [.., bound] = ¶m.bounds[..] {
2085 } else if let GenericParam {
2086 kind: GenericParamKind::Const { ty, kw_span: _, default }, ..
2088 default.as_ref().map(|def| def.value.span).unwrap_or(ty.span)
2092 (span, format!(", {}", ident))
2094 (generics.span, format!("<{}>", ident))
2096 // Do not suggest if this is coming from macro expansion.
2097 if span.can_be_used_for_suggestions() {
2099 span.shrink_to_hi(),
2102 Applicability::MaybeIncorrect,
2112 /// Given the target `label`, search the `rib_index`th label rib for similarly named labels,
2113 /// optionally returning the closest match and whether it is reachable.
2114 pub(crate) fn suggestion_for_label_in_rib(
2118 ) -> Option<LabelSuggestion> {
2119 // Are ribs from this `rib_index` within scope?
2120 let within_scope = self.is_label_valid_from_rib(rib_index);
2122 let rib = &self.label_ribs[rib_index];
2126 .filter(|(id, _)| id.span.eq_ctxt(label.span))
2127 .map(|(id, _)| id.name)
2128 .collect::<Vec<Symbol>>();
2130 find_best_match_for_name(&names, label.name, None).map(|symbol| {
2131 // Upon finding a similar name, get the ident that it was from - the span
2132 // contained within helps make a useful diagnostic. In addition, determine
2133 // whether this candidate is within scope.
2134 let (ident, _) = rib.bindings.iter().find(|(ident, _)| ident.name == symbol).unwrap();
2135 (*ident, within_scope)
2139 pub(crate) fn maybe_report_lifetime_uses(
2141 generics_span: Span,
2142 params: &[ast::GenericParam],
2144 for (param_index, param) in params.iter().enumerate() {
2145 let GenericParamKind::Lifetime = param.kind else { continue };
2147 let def_id = self.r.local_def_id(param.id);
2149 let use_set = self.lifetime_uses.remove(&def_id);
2151 "Use set for {:?}({:?} at {:?}) is {:?}",
2152 def_id, param.ident, param.ident.span, use_set
2155 let deletion_span = || {
2156 if params.len() == 1 {
2157 // if sole lifetime, remove the entire `<>` brackets
2159 } else if param_index == 0 {
2160 // if removing within `<>` brackets, we also want to
2161 // delete a leading or trailing comma as appropriate
2162 param.span().to(params[param_index + 1].span().shrink_to_lo())
2164 // if removing within `<>` brackets, we also want to
2165 // delete a leading or trailing comma as appropriate
2166 params[param_index - 1].span().shrink_to_hi().to(param.span())
2170 Some(LifetimeUseSet::Many) => {}
2171 Some(LifetimeUseSet::One { use_span, use_ctxt }) => {
2172 debug!(?param.ident, ?param.ident.span, ?use_span);
2174 let elidable = matches!(use_ctxt, LifetimeCtxt::Rptr);
2176 let deletion_span = deletion_span();
2177 self.r.lint_buffer.buffer_lint_with_diagnostic(
2178 lint::builtin::SINGLE_USE_LIFETIMES,
2181 &format!("lifetime parameter `{}` only used once", param.ident),
2182 lint::BuiltinLintDiagnostics::SingleUseLifetime {
2183 param_span: param.ident.span,
2184 use_span: Some((use_span, elidable)),
2190 debug!(?param.ident, ?param.ident.span);
2192 let deletion_span = deletion_span();
2193 self.r.lint_buffer.buffer_lint_with_diagnostic(
2194 lint::builtin::UNUSED_LIFETIMES,
2197 &format!("lifetime parameter `{}` never used", param.ident),
2198 lint::BuiltinLintDiagnostics::SingleUseLifetime {
2199 param_span: param.ident.span,
2209 pub(crate) fn emit_undeclared_lifetime_error(
2211 lifetime_ref: &ast::Lifetime,
2212 outer_lifetime_ref: Option<Ident>,
2214 debug_assert_ne!(lifetime_ref.ident.name, kw::UnderscoreLifetime);
2215 let mut err = if let Some(outer) = outer_lifetime_ref {
2216 let mut err = struct_span_err!(
2218 lifetime_ref.ident.span,
2220 "can't use generic parameters from outer item",
2222 err.span_label(lifetime_ref.ident.span, "use of generic parameter from outer item");
2223 err.span_label(outer.span, "lifetime parameter from outer item");
2226 let mut err = struct_span_err!(
2228 lifetime_ref.ident.span,
2230 "use of undeclared lifetime name `{}`",
2233 err.span_label(lifetime_ref.ident.span, "undeclared lifetime");
2236 self.suggest_introducing_lifetime(
2238 Some(lifetime_ref.ident.name.as_str()),
2239 |err, _, span, message, suggestion| {
2240 err.span_suggestion(span, message, suggestion, Applicability::MaybeIncorrect);
2247 fn suggest_introducing_lifetime(
2249 err: &mut Diagnostic,
2251 suggest: impl Fn(&mut Diagnostic, bool, Span, &str, String) -> bool,
2253 let mut suggest_note = true;
2254 for rib in self.lifetime_ribs.iter().rev() {
2255 let mut should_continue = true;
2257 LifetimeRibKind::Generics { binder: _, span, kind } => {
2258 if !span.can_be_used_for_suggestions() && suggest_note && let Some(name) = name {
2259 suggest_note = false; // Avoid displaying the same help multiple times.
2263 "lifetime `{}` is missing in item created through this procedural macro",
2270 let higher_ranked = matches!(
2272 LifetimeBinderKind::BareFnType
2273 | LifetimeBinderKind::PolyTrait
2274 | LifetimeBinderKind::WhereBound
2276 let (span, sugg) = if span.is_empty() {
2279 if higher_ranked { "for" } else { "" },
2280 name.unwrap_or("'a"),
2281 if higher_ranked { " " } else { "" },
2286 self.r.session.source_map().span_through_char(span, '<').shrink_to_hi();
2287 let sugg = format!("{}, ", name.unwrap_or("'a"));
2291 let message = format!(
2292 "consider making the {} lifetime-generic with a new `{}` lifetime",
2294 name.unwrap_or("'a"),
2296 should_continue = suggest(err, true, span, &message, sugg);
2298 "for more information on higher-ranked polymorphism, visit \
2299 https://doc.rust-lang.org/nomicon/hrtb.html",
2301 } else if let Some(name) = name {
2302 let message = format!("consider introducing lifetime `{}` here", name);
2303 should_continue = suggest(err, false, span, &message, sugg);
2305 let message = format!("consider introducing a named lifetime parameter");
2306 should_continue = suggest(err, false, span, &message, sugg);
2309 LifetimeRibKind::Item => break,
2312 if !should_continue {
2318 pub(crate) fn emit_non_static_lt_in_const_generic_error(&self, lifetime_ref: &ast::Lifetime) {
2321 lifetime_ref.ident.span,
2323 "use of non-static lifetime `{}` in const generic",
2327 "for more information, see issue #74052 \
2328 <https://github.com/rust-lang/rust/issues/74052>",
2333 /// Non-static lifetimes are prohibited in anonymous constants under `min_const_generics`.
2334 /// This function will emit an error if `generic_const_exprs` is not enabled, the body identified by
2335 /// `body_id` is an anonymous constant and `lifetime_ref` is non-static.
2336 pub(crate) fn maybe_emit_forbidden_non_static_lifetime_error(
2338 lifetime_ref: &ast::Lifetime,
2340 let feature_active = self.r.session.features_untracked().generic_const_exprs;
2341 if !feature_active {
2343 &self.r.session.parse_sess,
2344 sym::generic_const_exprs,
2345 lifetime_ref.ident.span,
2346 "a non-static lifetime is not allowed in a `const`",
2352 pub(crate) fn report_missing_lifetime_specifiers(
2354 lifetime_refs: Vec<MissingLifetime>,
2355 function_param_lifetimes: Option<(Vec<MissingLifetime>, Vec<ElisionFnParameter>)>,
2356 ) -> ErrorGuaranteed {
2357 let num_lifetimes: usize = lifetime_refs.iter().map(|lt| lt.count).sum();
2358 let spans: Vec<_> = lifetime_refs.iter().map(|lt| lt.span).collect();
2360 let mut err = struct_span_err!(
2364 "missing lifetime specifier{}",
2365 pluralize!(num_lifetimes)
2367 self.add_missing_lifetime_specifiers_label(
2370 function_param_lifetimes,
2375 fn add_missing_lifetime_specifiers_label(
2377 err: &mut Diagnostic,
2378 lifetime_refs: Vec<MissingLifetime>,
2379 function_param_lifetimes: Option<(Vec<MissingLifetime>, Vec<ElisionFnParameter>)>,
2381 for < in &lifetime_refs {
2385 "expected {} lifetime parameter{}",
2386 if lt.count == 1 { "named".to_string() } else { lt.count.to_string() },
2387 pluralize!(lt.count),
2392 let mut in_scope_lifetimes: Vec<_> = self
2396 .take_while(|rib| !matches!(rib.kind, LifetimeRibKind::Item))
2397 .flat_map(|rib| rib.bindings.iter())
2398 .map(|(&ident, &res)| (ident, res))
2399 .filter(|(ident, _)| ident.name != kw::UnderscoreLifetime)
2401 debug!(?in_scope_lifetimes);
2403 debug!(?function_param_lifetimes);
2404 if let Some((param_lifetimes, params)) = &function_param_lifetimes {
2405 let elided_len = param_lifetimes.len();
2406 let num_params = params.len();
2408 let mut m = String::new();
2410 for (i, info) in params.iter().enumerate() {
2411 let ElisionFnParameter { ident, index, lifetime_count, span } = *info;
2412 debug_assert_ne!(lifetime_count, 0);
2414 err.span_label(span, "");
2417 if i + 1 < num_params {
2419 } else if num_params == 2 {
2422 m.push_str(", or ");
2426 let help_name = if let Some(ident) = ident {
2427 format!("`{}`", ident)
2429 format!("argument {}", index + 1)
2432 if lifetime_count == 1 {
2433 m.push_str(&help_name[..])
2435 m.push_str(&format!("one of {}'s {} lifetimes", help_name, lifetime_count)[..])
2439 if num_params == 0 {
2441 "this function's return type contains a borrowed value, \
2442 but there is no value for it to be borrowed from",
2444 if in_scope_lifetimes.is_empty() {
2445 in_scope_lifetimes = vec![(
2446 Ident::with_dummy_span(kw::StaticLifetime),
2447 (DUMMY_NODE_ID, LifetimeRes::Static),
2450 } else if elided_len == 0 {
2452 "this function's return type contains a borrowed value with \
2453 an elided lifetime, but the lifetime cannot be derived from \
2456 if in_scope_lifetimes.is_empty() {
2457 in_scope_lifetimes = vec![(
2458 Ident::with_dummy_span(kw::StaticLifetime),
2459 (DUMMY_NODE_ID, LifetimeRes::Static),
2462 } else if num_params == 1 {
2464 "this function's return type contains a borrowed value, \
2465 but the signature does not say which {} it is borrowed from",
2470 "this function's return type contains a borrowed value, \
2471 but the signature does not say whether it is borrowed from {}",
2477 let existing_name = match &in_scope_lifetimes[..] {
2478 [] => Symbol::intern("'a"),
2479 [(existing, _)] => existing.name,
2480 _ => Symbol::intern("'lifetime"),
2483 let mut spans_suggs: Vec<_> = Vec::new();
2484 let build_sugg = |lt: MissingLifetime| match lt.kind {
2485 MissingLifetimeKind::Underscore => {
2486 debug_assert_eq!(lt.count, 1);
2487 (lt.span, existing_name.to_string())
2489 MissingLifetimeKind::Ampersand => {
2490 debug_assert_eq!(lt.count, 1);
2491 (lt.span.shrink_to_hi(), format!("{} ", existing_name))
2493 MissingLifetimeKind::Comma => {
2494 let sugg: String = std::iter::repeat([existing_name.as_str(), ", "])
2498 (lt.span.shrink_to_hi(), sugg)
2500 MissingLifetimeKind::Brackets => {
2501 let sugg: String = std::iter::once("<")
2503 std::iter::repeat(existing_name.as_str()).take(lt.count).intersperse(", "),
2507 (lt.span.shrink_to_hi(), sugg)
2510 for < in &lifetime_refs {
2511 spans_suggs.push(build_sugg(lt));
2513 debug!(?spans_suggs);
2514 match in_scope_lifetimes.len() {
2516 if let Some((param_lifetimes, _)) = function_param_lifetimes {
2517 for lt in param_lifetimes {
2518 spans_suggs.push(build_sugg(lt))
2521 self.suggest_introducing_lifetime(
2524 |err, higher_ranked, span, message, intro_sugg| {
2525 err.multipart_suggestion_verbose(
2527 std::iter::once((span, intro_sugg))
2528 .chain(spans_suggs.iter().cloned())
2530 Applicability::MaybeIncorrect,
2537 err.multipart_suggestion_verbose(
2538 &format!("consider using the `{}` lifetime", existing_name),
2540 Applicability::MaybeIncorrect,
2543 // Record as using the suggested resolution.
2544 let (_, (_, res)) = in_scope_lifetimes[0];
2545 for < in &lifetime_refs {
2546 self.r.lifetimes_res_map.insert(lt.id, res);
2550 let lifetime_spans: Vec<_> =
2551 in_scope_lifetimes.iter().map(|(ident, _)| ident.span).collect();
2552 err.span_note(lifetime_spans, "these named lifetimes are available to use");
2554 if spans_suggs.len() > 0 {
2555 // This happens when we have `Foo<T>` where we point at the space before `T`,
2556 // but this can be confusing so we give a suggestion with placeholders.
2557 err.multipart_suggestion_verbose(
2558 "consider using one of the available lifetimes here",
2560 Applicability::HasPlaceholders,
2568 /// Report lifetime/lifetime shadowing as an error.
2569 pub fn signal_lifetime_shadowing(sess: &Session, orig: Ident, shadower: Ident) {
2570 let mut err = struct_span_err!(
2574 "lifetime name `{}` shadows a lifetime name that is already in scope",
2577 err.span_label(orig.span, "first declared here");
2578 err.span_label(shadower.span, format!("lifetime `{}` already in scope", orig.name));
2582 /// Shadowing involving a label is only a warning for historical reasons.
2583 //FIXME: make this a proper lint.
2584 pub fn signal_label_shadowing(sess: &Session, orig: Span, shadower: Ident) {
2585 let name = shadower.name;
2586 let shadower = shadower.span;
2587 let mut err = sess.struct_span_warn(
2589 &format!("label name `{}` shadows a label name that is already in scope", name),
2591 err.span_label(orig, "first declared here");
2592 err.span_label(shadower, format!("label `{}` already in scope", name));