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 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 let Some(items) = self.diagnostic_metadata.current_impl_items
223 && let Some((fn_kind, _)) = self.diagnostic_metadata.current_function
224 && self.current_trait_ref.is_none()
225 && let Some(FnCtxt::Assoc(_)) = fn_kind.ctxt()
226 && let Some(item) = items.iter().find(|i| {
227 if let AssocItemKind::Fn(fn_) = &i.kind
228 && !fn_.sig.decl.has_self()
229 && i.ident.name == item_str.name
231 debug!(?item_str.name);
232 debug!(?fn_.sig.decl.inputs);
240 "consider using the associated function",
241 format!("Self::{}", item.ident)
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 let is_assoc_fn = self.self_type_is_available();
400 let Some(path_last_segment) = path.last() else { return };
401 let item_str = path_last_segment.ident;
402 // Emit help message for fake-self from other languages (e.g., `this` in Javascript).
403 if ["this", "my"].contains(&item_str.as_str()) && is_assoc_fn {
404 err.span_suggestion_short(
406 "you might have meant to use `self` here instead",
408 Applicability::MaybeIncorrect,
410 if !self.self_value_is_available(path[0].ident.span) {
411 if let Some((FnKind::Fn(_, _, sig, ..), fn_span)) =
412 &self.diagnostic_metadata.current_function
414 let (span, sugg) = if let Some(param) = sig.decl.inputs.get(0) {
415 (param.span.shrink_to_lo(), "&self, ")
421 .span_through_char(*fn_span, '(')
426 err.span_suggestion_verbose(
428 "if you meant to use `self`, you are also missing a `self` receiver \
431 Applicability::MaybeIncorrect,
438 fn try_lookup_name_relaxed(
440 err: &mut DiagnosticBuilder<'_, ErrorGuaranteed>,
441 source: PathSource<'_>,
445 base_error: &BaseError,
446 ) -> (bool, Vec<ImportSuggestion>) {
447 // Try to lookup name in more relaxed fashion for better error reporting.
448 let ident = path.last().unwrap().ident;
449 let is_expected = &|res| source.is_expected(res);
450 let ns = source.namespace();
451 let is_enum_variant = &|res| matches!(res, Res::Def(DefKind::Variant, _));
452 let path_str = Segment::names_to_string(path);
453 let ident_span = path.last().map_or(span, |ident| ident.ident.span);
455 let mut candidates = self
457 .lookup_import_candidates(ident, ns, &self.parent_scope, is_expected)
459 .filter(|ImportSuggestion { did, .. }| {
460 match (did, res.and_then(|res| res.opt_def_id())) {
461 (Some(suggestion_did), Some(actual_did)) => *suggestion_did != actual_did,
465 .collect::<Vec<_>>();
466 let crate_def_id = CRATE_DEF_ID.to_def_id();
467 // Try to filter out intrinsics candidates, as long as we have
468 // some other candidates to suggest.
469 let intrinsic_candidates: Vec<_> = candidates
470 .drain_filter(|sugg| {
471 let path = path_names_to_string(&sugg.path);
472 path.starts_with("core::intrinsics::") || path.starts_with("std::intrinsics::")
475 if candidates.is_empty() {
476 // Put them back if we have no more candidates to suggest...
477 candidates.extend(intrinsic_candidates);
479 if candidates.is_empty() && is_expected(Res::Def(DefKind::Enum, crate_def_id)) {
480 let mut enum_candidates: Vec<_> = self
482 .lookup_import_candidates(ident, ns, &self.parent_scope, is_enum_variant)
484 .map(|suggestion| import_candidate_to_enum_paths(&suggestion))
485 .filter(|(_, enum_ty_path)| !enum_ty_path.starts_with("std::prelude::"))
487 if !enum_candidates.is_empty() {
488 if let (PathSource::Type, Some(span)) =
489 (source, self.diagnostic_metadata.current_type_ascription.last())
495 .type_ascription_path_suggestions
499 // Already reported this issue on the lhs of the type ascription.
501 return (true, candidates);
505 enum_candidates.sort();
507 // Contextualize for E0412 "cannot find type", but don't belabor the point
508 // (that it's a variant) for E0573 "expected type, found variant".
509 let preamble = if res.is_none() {
510 let others = match enum_candidates.len() {
512 2 => " and 1 other".to_owned(),
513 n => format!(" and {} others", n),
515 format!("there is an enum variant `{}`{}; ", enum_candidates[0].0, others)
519 let msg = format!("{}try using the variant's enum", preamble);
521 err.span_suggestions(
524 enum_candidates.into_iter().map(|(_variant_path, enum_ty_path)| enum_ty_path),
525 Applicability::MachineApplicable,
530 // Try Levenshtein algorithm.
532 self.lookup_typo_candidate(path, source.namespace(), is_expected).to_opt_suggestion();
533 if path.len() == 1 && self.self_type_is_available() {
534 if let Some(candidate) =
535 self.lookup_assoc_candidate(ident, ns, is_expected, source.is_call())
537 let self_is_available = self.self_value_is_available(path[0].ident.span);
539 AssocSuggestion::Field => {
540 if self_is_available {
543 "you might have meant to use the available field",
544 format!("self.{path_str}"),
545 Applicability::MachineApplicable,
548 err.span_label(span, "a field by this name exists in `Self`");
551 AssocSuggestion::MethodWithSelf { called } if self_is_available => {
552 let msg = if called {
553 "you might have meant to call the method"
555 "you might have meant to refer to the method"
560 format!("self.{path_str}"),
561 Applicability::MachineApplicable,
564 AssocSuggestion::MethodWithSelf { .. }
565 | AssocSuggestion::AssocFn { .. }
566 | AssocSuggestion::AssocConst
567 | AssocSuggestion::AssocType => {
570 &format!("you might have meant to {}", candidate.action()),
571 format!("Self::{path_str}"),
572 Applicability::MachineApplicable,
576 self.r.add_typo_suggestion(err, typo_sugg, ident_span);
577 return (true, candidates);
580 // If the first argument in call is `self` suggest calling a method.
581 if let Some((call_span, args_span)) = self.call_has_self_arg(source) {
582 let mut args_snippet = String::new();
583 if let Some(args_span) = args_span {
584 if let Ok(snippet) = self.r.session.source_map().span_to_snippet(args_span) {
585 args_snippet = snippet;
591 &format!("try calling `{ident}` as a method"),
592 format!("self.{path_str}({args_snippet})"),
593 Applicability::MachineApplicable,
595 return (true, candidates);
599 // Try context-dependent help if relaxed lookup didn't work.
600 if let Some(res) = res {
601 if self.smart_resolve_context_dependent_help(
607 &base_error.fallback_label,
609 // We do this to avoid losing a secondary span when we override the main error span.
610 self.r.add_typo_suggestion(err, typo_sugg, ident_span);
611 return (true, candidates);
614 return (false, candidates);
617 fn suggest_trait_and_bounds(
619 err: &mut DiagnosticBuilder<'_, ErrorGuaranteed>,
620 source: PathSource<'_>,
623 base_error: &BaseError,
626 base_error.span.from_expansion() && base_error.span.desugaring_kind().is_none();
627 let mut fallback = false;
630 PathSource::Trait(AliasPossibility::Maybe),
631 Some(Res::Def(DefKind::Struct | DefKind::Enum | DefKind::Union, _)),
633 ) = (source, res, is_macro)
635 if let Some(bounds @ [_, .., _]) = self.diagnostic_metadata.current_trait_object {
637 let spans: Vec<Span> = bounds
639 .map(|bound| bound.span())
640 .filter(|&sp| sp != base_error.span)
643 let start_span = bounds[0].span();
644 // `end_span` is the end of the poly trait ref (Foo + 'baz + Bar><)
645 let end_span = bounds.last().unwrap().span();
646 // `last_bound_span` is the last bound of the poly trait ref (Foo + >'baz< + Bar)
647 let last_bound_span = spans.last().cloned().unwrap();
648 let mut multi_span: MultiSpan = spans.clone().into();
650 let msg = if sp == last_bound_span {
652 "...because of {these} bound{s}",
653 these = pluralize!("this", bounds.len() - 1),
654 s = pluralize!(bounds.len() - 1),
659 multi_span.push_span_label(sp, msg);
661 multi_span.push_span_label(base_error.span, "expected this type to be a trait...");
664 "`+` is used to constrain a \"trait object\" type with lifetimes or \
665 auto-traits; structs and enums can't be bound in that way",
667 if bounds.iter().all(|bound| match bound {
668 ast::GenericBound::Outlives(_) => true,
669 ast::GenericBound::Trait(tr, _) => tr.span == base_error.span,
671 let mut sugg = vec![];
672 if base_error.span != start_span {
673 sugg.push((start_span.until(base_error.span), String::new()));
675 if base_error.span != end_span {
676 sugg.push((base_error.span.shrink_to_hi().to(end_span), String::new()));
679 err.multipart_suggestion(
680 "if you meant to use a type and not a trait here, remove the bounds",
682 Applicability::MaybeIncorrect,
688 fallback |= self.restrict_assoc_type_in_where_clause(span, err);
694 err: &mut DiagnosticBuilder<'_, ErrorGuaranteed>,
695 source: PathSource<'_>,
698 base_error: &BaseError,
700 let is_expected = &|res| source.is_expected(res);
701 let ident_span = path.last().map_or(span, |ident| ident.ident.span);
702 let typo_sugg = self.lookup_typo_candidate(path, source.namespace(), is_expected);
703 let is_in_same_file = &|sp1, sp2| {
704 let source_map = self.r.session.source_map();
705 let file1 = source_map.span_to_filename(sp1);
706 let file2 = source_map.span_to_filename(sp2);
709 // print 'you might have meant' if the candidate is (1) is a shadowed name with
710 // accessible definition and (2) either defined in the same crate as the typo
711 // (could be in a different file) or introduced in the same file as the typo
712 // (could belong to a different crate)
713 if let TypoCandidate::Shadowed(res, Some(sugg_span)) = typo_sugg
716 .map_or(false, |id| id.is_local() || is_in_same_file(span, sugg_span))
720 format!("you might have meant to refer to this {}", res.descr()),
724 let mut fallback = false;
725 let typo_sugg = typo_sugg.to_opt_suggestion();
726 if !self.r.add_typo_suggestion(err, typo_sugg, ident_span) {
728 match self.diagnostic_metadata.current_let_binding {
729 Some((pat_sp, Some(ty_sp), None))
730 if ty_sp.contains(base_error.span) && base_error.could_be_expr =>
732 err.span_suggestion_short(
733 pat_sp.between(ty_sp),
734 "use `=` if you meant to assign",
736 Applicability::MaybeIncorrect,
742 // If the trait has a single item (which wasn't matched by Levenshtein), suggest it
743 let suggestion = self.get_single_associated_item(&path, &source, is_expected);
744 if !self.r.add_typo_suggestion(err, suggestion, ident_span) {
745 fallback = !self.let_binding_suggestion(err, ident_span);
751 fn err_code_special_cases(
753 err: &mut DiagnosticBuilder<'_, ErrorGuaranteed>,
754 source: PathSource<'_>,
758 if let Some(err_code) = &err.code {
759 if err_code == &rustc_errors::error_code!(E0425) {
760 for label_rib in &self.label_ribs {
761 for (label_ident, node_id) in &label_rib.bindings {
762 let ident = path.last().unwrap().ident;
763 if format!("'{}", ident) == label_ident.to_string() {
764 err.span_label(label_ident.span, "a label with a similar name exists");
765 if let PathSource::Expr(Some(Expr {
766 kind: ExprKind::Break(None, Some(_)),
772 "use the similarly named label",
774 Applicability::MaybeIncorrect,
776 // Do not lint against unused label when we suggest them.
777 self.diagnostic_metadata.unused_labels.remove(node_id);
782 } else if err_code == &rustc_errors::error_code!(E0412) {
783 if let Some(correct) = Self::likely_rust_type(path) {
786 "perhaps you intended to use this type",
788 Applicability::MaybeIncorrect,
795 /// Emit special messages for unresolved `Self` and `self`.
798 err: &mut Diagnostic,
799 source: PathSource<'_>,
803 if !is_self_type(path, source.namespace()) {
806 err.code(rustc_errors::error_code!(E0411));
807 err.span_label(span, "`Self` is only available in impls, traits, and type definitions");
808 if let Some(item_kind) = self.diagnostic_metadata.current_item {
810 item_kind.ident.span,
812 "`Self` not allowed in {} {}",
813 item_kind.kind.article(),
814 item_kind.kind.descr()
821 fn suggest_self_value(
823 err: &mut Diagnostic,
824 source: PathSource<'_>,
828 if !is_self_value(path, source.namespace()) {
832 debug!("smart_resolve_path_fragment: E0424, source={:?}", source);
833 err.code(rustc_errors::error_code!(E0424));
838 "`self` value is a keyword and may not be bound to variables or shadowed"
840 _ => "`self` value is a keyword only available in methods with a `self` parameter",
843 let is_assoc_fn = self.self_type_is_available();
844 if let Some((fn_kind, span)) = &self.diagnostic_metadata.current_function {
845 // The current function has a `self' parameter, but we were unable to resolve
846 // a reference to `self`. This can only happen if the `self` identifier we
847 // are resolving came from a different hygiene context.
848 if fn_kind.decl().inputs.get(0).map_or(false, |p| p.is_self()) {
849 err.span_label(*span, "this function has a `self` parameter, but a macro invocation can only access identifiers it receives from parameters");
851 let doesnt = if is_assoc_fn {
852 let (span, sugg) = fn_kind
856 .map(|p| (p.span.shrink_to_lo(), "&self, "))
858 // Try to look for the "(" after the function name, if possible.
859 // This avoids placing the suggestion into the visibility specifier.
862 .map_or(*span, |ident| span.with_lo(ident.span.hi()));
867 .span_through_char(span, '(')
872 err.span_suggestion_verbose(
874 "add a `self` receiver parameter to make the associated `fn` a method",
876 Applicability::MaybeIncorrect,
882 if let Some(ident) = fn_kind.ident() {
885 &format!("this function {} have a `self` parameter", doesnt),
889 } else if let Some(item_kind) = self.diagnostic_metadata.current_item {
891 item_kind.ident.span,
893 "`self` not allowed in {} {}",
894 item_kind.kind.article(),
895 item_kind.kind.descr()
902 fn suggest_swapping_misplaced_self_ty_and_trait(
904 err: &mut Diagnostic,
905 source: PathSource<'_>,
909 if let Some((trait_ref, self_ty)) =
910 self.diagnostic_metadata.currently_processing_impl_trait.clone()
911 && let TyKind::Path(_, self_ty_path) = &self_ty.kind
912 && let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
913 self.resolve_path(&Segment::from_path(self_ty_path), Some(TypeNS), None)
914 && let ModuleKind::Def(DefKind::Trait, ..) = module.kind
915 && trait_ref.path.span == span
916 && let PathSource::Trait(_) = source
917 && let Some(Res::Def(DefKind::Struct | DefKind::Enum | DefKind::Union, _)) = res
918 && let Ok(self_ty_str) =
919 self.r.session.source_map().span_to_snippet(self_ty.span)
920 && let Ok(trait_ref_str) =
921 self.r.session.source_map().span_to_snippet(trait_ref.path.span)
923 err.multipart_suggestion(
924 "`impl` items mention the trait being implemented first and the type it is being implemented for second",
925 vec![(trait_ref.path.span, self_ty_str), (self_ty.span, trait_ref_str)],
926 Applicability::MaybeIncorrect,
931 fn suggest_bare_struct_literal(&mut self, err: &mut Diagnostic) {
932 if let Some(span) = self.diagnostic_metadata.current_block_could_be_bare_struct_literal {
933 err.multipart_suggestion(
934 "you might have meant to write a `struct` literal",
936 (span.shrink_to_lo(), "{ SomeStruct ".to_string()),
937 (span.shrink_to_hi(), "}".to_string()),
939 Applicability::HasPlaceholders,
944 fn suggest_pattern_match_with_let(
946 err: &mut Diagnostic,
947 source: PathSource<'_>,
950 if let PathSource::Expr(_) = source &&
953 kind: ExprKind::Assign(lhs, _, _),
955 }) = self.diagnostic_metadata.in_if_condition {
956 // Icky heuristic so we don't suggest:
957 // `if (i + 2) = 2` => `if let (i + 2) = 2` (approximately pattern)
958 // `if 2 = i` => `if let 2 = i` (lhs needs to contain error span)
959 if lhs.is_approximately_pattern() && lhs.span.contains(span) {
960 err.span_suggestion_verbose(
961 expr_span.shrink_to_lo(),
962 "you might have meant to use pattern matching",
964 Applicability::MaybeIncorrect,
972 fn get_single_associated_item(
975 source: &PathSource<'_>,
976 filter_fn: &impl Fn(Res) -> bool,
977 ) -> Option<TypoSuggestion> {
978 if let crate::PathSource::TraitItem(_) = source {
979 let mod_path = &path[..path.len() - 1];
980 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
981 self.resolve_path(mod_path, None, None)
983 let resolutions = self.r.resolutions(module).borrow();
984 let targets: Vec<_> =
987 .filter_map(|(key, resolution)| {
988 resolution.borrow().binding.map(|binding| binding.res()).and_then(
989 |res| if filter_fn(res) { Some((key, res)) } else { None },
993 if targets.len() == 1 {
994 let target = targets[0];
995 return Some(TypoSuggestion::single_item_from_ident(target.0.ident, target.1));
1002 /// Given `where <T as Bar>::Baz: String`, suggest `where T: Bar<Baz = String>`.
1003 fn restrict_assoc_type_in_where_clause(&mut self, span: Span, err: &mut Diagnostic) -> bool {
1004 // Detect that we are actually in a `where` predicate.
1005 let (bounded_ty, bounds, where_span) =
1006 if let Some(ast::WherePredicate::BoundPredicate(ast::WhereBoundPredicate {
1008 bound_generic_params,
1011 })) = self.diagnostic_metadata.current_where_predicate
1013 if !bound_generic_params.is_empty() {
1016 (bounded_ty, bounds, span)
1021 // Confirm that the target is an associated type.
1022 let (ty, position, path) = if let ast::TyKind::Path(
1023 Some(ast::QSelf { ty, position, .. }),
1025 ) = &bounded_ty.kind
1027 // use this to verify that ident is a type param.
1028 let Some(partial_res) = self.r.partial_res_map.get(&bounded_ty.id) else {
1032 partial_res.full_res(),
1033 Some(hir::def::Res::Def(hir::def::DefKind::AssocTy, _))
1037 (ty, position, path)
1042 let peeled_ty = ty.peel_refs();
1043 if let ast::TyKind::Path(None, type_param_path) = &peeled_ty.kind {
1044 // Confirm that the `SelfTy` is a type parameter.
1045 let Some(partial_res) = self.r.partial_res_map.get(&peeled_ty.id) else {
1049 partial_res.full_res(),
1050 Some(hir::def::Res::Def(hir::def::DefKind::TyParam, _))
1055 [ast::PathSegment { ident: constrain_ident, args: None, .. }],
1056 [ast::GenericBound::Trait(poly_trait_ref, ast::TraitBoundModifier::None)],
1057 ) = (&type_param_path.segments[..], &bounds[..])
1059 if let [ast::PathSegment { ident, args: None, .. }] =
1060 &poly_trait_ref.trait_ref.path.segments[..]
1062 if ident.span == span {
1063 err.span_suggestion_verbose(
1065 &format!("constrain the associated type to `{}`", ident),
1071 .span_to_snippet(ty.span) // Account for `<&'a T as Foo>::Bar`.
1072 .unwrap_or_else(|_| constrain_ident.to_string()),
1073 path.segments[..*position]
1075 .map(|segment| path_segment_to_string(segment))
1076 .collect::<Vec<_>>()
1078 path.segments[*position..]
1080 .map(|segment| path_segment_to_string(segment))
1081 .collect::<Vec<_>>()
1085 Applicability::MaybeIncorrect,
1095 /// Check if the source is call expression and the first argument is `self`. If true,
1096 /// return the span of whole call and the span for all arguments expect the first one (`self`).
1097 fn call_has_self_arg(&self, source: PathSource<'_>) -> Option<(Span, Option<Span>)> {
1098 let mut has_self_arg = None;
1099 if let PathSource::Expr(Some(parent)) = source {
1100 match &parent.kind {
1101 ExprKind::Call(_, args) if !args.is_empty() => {
1102 let mut expr_kind = &args[0].kind;
1105 ExprKind::Path(_, arg_name) if arg_name.segments.len() == 1 => {
1106 if arg_name.segments[0].ident.name == kw::SelfLower {
1107 let call_span = parent.span;
1108 let tail_args_span = if args.len() > 1 {
1111 args.last().unwrap().span.hi(),
1118 has_self_arg = Some((call_span, tail_args_span));
1122 ExprKind::AddrOf(_, _, expr) => expr_kind = &expr.kind,
1133 fn followed_by_brace(&self, span: Span) -> (bool, Option<Span>) {
1134 // HACK(estebank): find a better way to figure out that this was a
1135 // parser issue where a struct literal is being used on an expression
1136 // where a brace being opened means a block is being started. Look
1137 // ahead for the next text to see if `span` is followed by a `{`.
1138 let sm = self.r.session.source_map();
1139 let sp = sm.span_look_ahead(span, None, Some(50));
1140 let followed_by_brace = matches!(sm.span_to_snippet(sp), Ok(ref snippet) if snippet == "{");
1141 // In case this could be a struct literal that needs to be surrounded
1142 // by parentheses, find the appropriate span.
1143 let closing_span = sm.span_look_ahead(span, Some("}"), Some(50));
1144 let closing_brace: Option<Span> = sm
1145 .span_to_snippet(closing_span)
1146 .map_or(None, |s| if s == "}" { Some(span.to(closing_span)) } else { None });
1147 (followed_by_brace, closing_brace)
1150 /// Provides context-dependent help for errors reported by the `smart_resolve_path_fragment`
1152 /// Returns `true` if able to provide context-dependent help.
1153 fn smart_resolve_context_dependent_help(
1155 err: &mut Diagnostic,
1157 source: PathSource<'_>,
1160 fallback_label: &str,
1162 let ns = source.namespace();
1163 let is_expected = &|res| source.is_expected(res);
1165 let path_sep = |err: &mut Diagnostic, expr: &Expr, kind: DefKind| {
1166 const MESSAGE: &str = "use the path separator to refer to an item";
1168 let (lhs_span, rhs_span) = match &expr.kind {
1169 ExprKind::Field(base, ident) => (base.span, ident.span),
1170 ExprKind::MethodCall(_, receiver, _, span) => (receiver.span, *span),
1174 if lhs_span.eq_ctxt(rhs_span) {
1175 err.span_suggestion(
1176 lhs_span.between(rhs_span),
1179 Applicability::MaybeIncorrect,
1182 } else if kind == DefKind::Struct
1183 && let Some(lhs_source_span) = lhs_span.find_ancestor_inside(expr.span)
1184 && let Ok(snippet) = self.r.session.source_map().span_to_snippet(lhs_source_span)
1186 // The LHS is a type that originates from a macro call.
1187 // We have to add angle brackets around it.
1189 err.span_suggestion_verbose(
1190 lhs_source_span.until(rhs_span),
1192 format!("<{snippet}>::"),
1193 Applicability::MaybeIncorrect,
1197 // Either we were unable to obtain the source span / the snippet or
1198 // the LHS originates from a macro call and it is not a type and thus
1199 // there is no way to replace `.` with `::` and still somehow suggest
1206 let find_span = |source: &PathSource<'_>, err: &mut Diagnostic| {
1208 PathSource::Expr(Some(Expr { span, kind: ExprKind::Call(_, _), .. }))
1209 | PathSource::TupleStruct(span, _) => {
1210 // We want the main underline to cover the suggested code as well for
1212 err.set_span(*span);
1219 let mut bad_struct_syntax_suggestion = |def_id: DefId| {
1220 let (followed_by_brace, closing_brace) = self.followed_by_brace(span);
1223 PathSource::Expr(Some(
1224 parent @ Expr { kind: ExprKind::Field(..) | ExprKind::MethodCall(..), .. },
1225 )) if path_sep(err, &parent, DefKind::Struct) => {}
1231 | ExprKind::Binary(..)
1232 | ExprKind::Unary(..)
1234 | ExprKind::While(..)
1235 | ExprKind::ForLoop(..)
1236 | ExprKind::Match(..),
1239 ) if followed_by_brace => {
1240 if let Some(sp) = closing_brace {
1241 err.span_label(span, fallback_label);
1242 err.multipart_suggestion(
1243 "surround the struct literal with parentheses",
1245 (sp.shrink_to_lo(), "(".to_string()),
1246 (sp.shrink_to_hi(), ")".to_string()),
1248 Applicability::MaybeIncorrect,
1252 span, // Note the parentheses surrounding the suggestion below
1254 "you might want to surround a struct literal with parentheses: \
1255 `({} {{ /* fields */ }})`?",
1261 PathSource::Expr(_) | PathSource::TupleStruct(..) | PathSource::Pat => {
1262 let span = find_span(&source, err);
1263 if let Some(span) = self.def_span(def_id) {
1264 err.span_label(span, &format!("`{}` defined here", path_str));
1266 let (tail, descr, applicability) = match source {
1267 PathSource::Pat | PathSource::TupleStruct(..) => {
1268 ("", "pattern", Applicability::MachineApplicable)
1270 _ => (": val", "literal", Applicability::HasPlaceholders),
1272 let (fields, applicability) = match self.r.field_names.get(&def_id) {
1276 .map(|f| format!("{}{}", f.node, tail))
1277 .collect::<Vec<String>>()
1281 None => ("/* fields */".to_string(), Applicability::HasPlaceholders),
1283 let pad = match self.r.field_names.get(&def_id) {
1284 Some(fields) if fields.is_empty() => "",
1287 err.span_suggestion(
1289 &format!("use struct {} syntax instead", descr),
1290 format!("{path_str} {{{pad}{fields}{pad}}}"),
1295 err.span_label(span, fallback_label);
1300 match (res, source) {
1302 Res::Def(DefKind::Macro(MacroKind::Bang), _),
1303 PathSource::Expr(Some(Expr {
1304 kind: ExprKind::Index(..) | ExprKind::Call(..), ..
1306 | PathSource::Struct,
1308 err.span_label(span, fallback_label);
1309 err.span_suggestion_verbose(
1310 span.shrink_to_hi(),
1311 "use `!` to invoke the macro",
1313 Applicability::MaybeIncorrect,
1315 if path_str == "try" && span.rust_2015() {
1316 err.note("if you want the `try` keyword, you need Rust 2018 or later");
1319 (Res::Def(DefKind::Macro(MacroKind::Bang), _), _) => {
1320 err.span_label(span, fallback_label);
1322 (Res::Def(DefKind::TyAlias, def_id), PathSource::Trait(_)) => {
1323 err.span_label(span, "type aliases cannot be used as traits");
1324 if self.r.session.is_nightly_build() {
1325 let msg = "you might have meant to use `#![feature(trait_alias)]` instead of a \
1327 if let Some(span) = self.def_span(def_id) {
1328 if let Ok(snip) = self.r.session.source_map().span_to_snippet(span) {
1329 // The span contains a type alias so we should be able to
1330 // replace `type` with `trait`.
1331 let snip = snip.replacen("type", "trait", 1);
1332 err.span_suggestion(span, msg, snip, Applicability::MaybeIncorrect);
1334 err.span_help(span, msg);
1342 Res::Def(kind @ (DefKind::Mod | DefKind::Trait), _),
1343 PathSource::Expr(Some(parent)),
1345 if !path_sep(err, &parent, kind) {
1350 Res::Def(DefKind::Enum, def_id),
1351 PathSource::TupleStruct(..) | PathSource::Expr(..),
1354 .diagnostic_metadata
1355 .current_type_ascription
1361 .type_ascription_path_suggestions
1367 err.downgrade_to_delayed_bug();
1368 // We already suggested changing `:` into `::` during parsing.
1372 self.suggest_using_enum_variant(err, source, def_id, span);
1374 (Res::Def(DefKind::Struct, def_id), source) if ns == ValueNS => {
1375 let (ctor_def, ctor_vis, fields) =
1376 if let Some(struct_ctor) = self.r.struct_constructors.get(&def_id).cloned() {
1377 if let PathSource::Expr(Some(parent)) = source {
1378 if let ExprKind::Field(..) | ExprKind::MethodCall(..) = parent.kind {
1379 bad_struct_syntax_suggestion(def_id);
1385 bad_struct_syntax_suggestion(def_id);
1389 let is_accessible = self.r.is_accessible_from(ctor_vis, self.parent_scope.module);
1390 if !is_expected(ctor_def) || is_accessible {
1394 let field_spans = match source {
1395 // e.g. `if let Enum::TupleVariant(field1, field2) = _`
1396 PathSource::TupleStruct(_, pattern_spans) => {
1397 err.set_primary_message(
1398 "cannot match against a tuple struct which contains private fields",
1401 // Use spans of the tuple struct pattern.
1402 Some(Vec::from(pattern_spans))
1404 // e.g. `let _ = Enum::TupleVariant(field1, field2);`
1405 _ if source.is_call() => {
1406 err.set_primary_message(
1407 "cannot initialize a tuple struct which contains private fields",
1410 // Use spans of the tuple struct definition.
1414 .map(|fields| fields.iter().map(|f| f.span).collect::<Vec<_>>())
1419 if let Some(spans) =
1420 field_spans.filter(|spans| spans.len() > 0 && fields.len() == spans.len())
1422 let non_visible_spans: Vec<Span> = iter::zip(&fields, &spans)
1423 .filter(|(vis, _)| {
1424 !self.r.is_accessible_from(**vis, self.parent_scope.module)
1426 .map(|(_, span)| *span)
1429 if non_visible_spans.len() > 0 {
1430 let mut m: MultiSpan = non_visible_spans.clone().into();
1433 .for_each(|s| m.push_span_label(s, "private field"));
1434 err.span_note(m, "constructor is not visible here due to private fields");
1440 err.span_label(span, "constructor is not visible here due to private fields");
1444 DefKind::Union | DefKind::Variant | DefKind::Ctor(_, CtorKind::Fictive),
1448 ) if ns == ValueNS => {
1449 bad_struct_syntax_suggestion(def_id);
1451 (Res::Def(DefKind::Ctor(_, CtorKind::Const), def_id), _) if ns == ValueNS => {
1453 PathSource::Expr(_) | PathSource::TupleStruct(..) | PathSource::Pat => {
1454 let span = find_span(&source, err);
1455 if let Some(span) = self.def_span(def_id) {
1456 err.span_label(span, &format!("`{}` defined here", path_str));
1458 err.span_suggestion(
1460 "use this syntax instead",
1462 Applicability::MaybeIncorrect,
1468 (Res::Def(DefKind::Ctor(_, CtorKind::Fn), def_id), _) if ns == ValueNS => {
1469 if let Some(span) = self.def_span(def_id) {
1470 err.span_label(span, &format!("`{}` defined here", path_str));
1472 let fields = self.r.field_names.get(&def_id).map_or_else(
1473 || "/* fields */".to_string(),
1474 |fields| vec!["_"; fields.len()].join(", "),
1476 err.span_suggestion(
1478 "use the tuple variant pattern syntax instead",
1479 format!("{}({})", path_str, fields),
1480 Applicability::HasPlaceholders,
1483 (Res::SelfTyParam { .. } | Res::SelfTyAlias { .. }, _) if ns == ValueNS => {
1484 err.span_label(span, fallback_label);
1485 err.note("can't use `Self` as a constructor, you must use the implemented struct");
1487 (Res::Def(DefKind::TyAlias | DefKind::AssocTy, _), _) if ns == ValueNS => {
1488 err.note("can't use a type alias as a constructor");
1495 /// Given the target `ident` and `kind`, search for the similarly named associated item
1496 /// in `self.current_trait_ref`.
1497 pub(crate) fn find_similarly_named_assoc_item(
1500 kind: &AssocItemKind,
1501 ) -> Option<Symbol> {
1502 let (module, _) = self.current_trait_ref.as_ref()?;
1503 if ident == kw::Underscore {
1504 // We do nothing for `_`.
1508 let resolutions = self.r.resolutions(module);
1509 let targets = resolutions
1512 .filter_map(|(key, res)| res.borrow().binding.map(|binding| (key, binding.res())))
1513 .filter(|(_, res)| match (kind, res) {
1514 (AssocItemKind::Const(..), Res::Def(DefKind::AssocConst, _)) => true,
1515 (AssocItemKind::Fn(_), Res::Def(DefKind::AssocFn, _)) => true,
1516 (AssocItemKind::Type(..), Res::Def(DefKind::AssocTy, _)) => true,
1519 .map(|(key, _)| key.ident.name)
1520 .collect::<Vec<_>>();
1522 find_best_match_for_name(&targets, ident, None)
1525 fn lookup_assoc_candidate<FilterFn>(
1529 filter_fn: FilterFn,
1531 ) -> Option<AssocSuggestion>
1533 FilterFn: Fn(Res) -> bool,
1535 fn extract_node_id(t: &Ty) -> Option<NodeId> {
1537 TyKind::Path(None, _) => Some(t.id),
1538 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
1539 // This doesn't handle the remaining `Ty` variants as they are not
1540 // that commonly the self_type, it might be interesting to provide
1541 // 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 fn let_binding_suggestion(&self, err: &mut Diagnostic, ident_span: Span) -> bool {
1814 // try to give a suggestion for this pattern: `name = 1`, which is common in other languages
1815 let mut added_suggestion = false;
1816 if let Some(Expr { kind: ExprKind::Assign(lhs, _rhs, _), .. }) = self.diagnostic_metadata.in_assignment &&
1817 let ast::ExprKind::Path(None, _) = lhs.kind {
1818 let sm = self.r.session.source_map();
1819 let line_span = sm.span_extend_to_line(ident_span);
1820 let ident_name = sm.span_to_snippet(ident_span).unwrap();
1821 // HACK(chenyukang): make sure ident_name is at the starting of the line to protect against macros
1823 .span_to_snippet(line_span)
1824 .map_or(false, |s| s.trim().starts_with(&ident_name))
1826 err.span_suggestion_verbose(
1827 ident_span.shrink_to_lo(),
1828 "you might have meant to introduce a new binding",
1830 Applicability::MaybeIncorrect,
1832 added_suggestion = true;
1838 fn find_module(&mut self, def_id: DefId) -> Option<(Module<'a>, ImportSuggestion)> {
1839 let mut result = None;
1840 let mut seen_modules = FxHashSet::default();
1841 let mut worklist = vec![(self.r.graph_root, Vec::new())];
1843 while let Some((in_module, path_segments)) = worklist.pop() {
1844 // abort if the module is already found
1845 if result.is_some() {
1849 in_module.for_each_child(self.r, |_, ident, _, name_binding| {
1850 // abort if the module is already found or if name_binding is private external
1851 if result.is_some() || !name_binding.vis.is_visible_locally() {
1854 if let Some(module) = name_binding.module() {
1856 let mut path_segments = path_segments.clone();
1857 path_segments.push(ast::PathSegment::from_ident(ident));
1858 let module_def_id = module.def_id();
1859 if module_def_id == def_id {
1861 Path { span: name_binding.span, segments: path_segments, tokens: None };
1873 // add the module to the lookup
1874 if seen_modules.insert(module_def_id) {
1875 worklist.push((module, path_segments));
1885 fn collect_enum_ctors(&mut self, def_id: DefId) -> Option<Vec<(Path, DefId, CtorKind)>> {
1886 self.find_module(def_id).map(|(enum_module, enum_import_suggestion)| {
1887 let mut variants = Vec::new();
1888 enum_module.for_each_child(self.r, |_, ident, _, name_binding| {
1889 if let Res::Def(DefKind::Ctor(CtorOf::Variant, kind), def_id) = name_binding.res() {
1890 let mut segms = enum_import_suggestion.path.segments.clone();
1891 segms.push(ast::PathSegment::from_ident(ident));
1892 let path = Path { span: name_binding.span, segments: segms, tokens: None };
1893 variants.push((path, def_id, kind));
1900 /// Adds a suggestion for using an enum's variant when an enum is used instead.
1901 fn suggest_using_enum_variant(
1903 err: &mut Diagnostic,
1904 source: PathSource<'_>,
1908 let Some(variants) = self.collect_enum_ctors(def_id) else {
1909 err.note("you might have meant to use one of the enum's variants");
1913 let suggest_only_tuple_variants =
1914 matches!(source, PathSource::TupleStruct(..)) || source.is_call();
1915 if suggest_only_tuple_variants {
1916 // Suggest only tuple variants regardless of whether they have fields and do not
1917 // suggest path with added parentheses.
1918 let suggestable_variants = variants
1920 .filter(|(.., kind)| *kind == CtorKind::Fn)
1921 .map(|(variant, ..)| path_names_to_string(variant))
1922 .collect::<Vec<_>>();
1924 let non_suggestable_variant_count = variants.len() - suggestable_variants.len();
1926 let source_msg = if source.is_call() {
1928 } else if matches!(source, PathSource::TupleStruct(..)) {
1934 if !suggestable_variants.is_empty() {
1935 let msg = if non_suggestable_variant_count == 0 && suggestable_variants.len() == 1 {
1936 format!("try {} the enum's variant", source_msg)
1938 format!("try {} one of the enum's variants", source_msg)
1941 err.span_suggestions(
1944 suggestable_variants.into_iter(),
1945 Applicability::MaybeIncorrect,
1949 // If the enum has no tuple variants..
1950 if non_suggestable_variant_count == variants.len() {
1951 err.help(&format!("the enum has no tuple variants {}", source_msg));
1954 // If there are also non-tuple variants..
1955 if non_suggestable_variant_count == 1 {
1957 "you might have meant {} the enum's non-tuple variant",
1960 } else if non_suggestable_variant_count >= 1 {
1962 "you might have meant {} one of the enum's non-tuple variants",
1967 let needs_placeholder = |def_id: DefId, kind: CtorKind| {
1968 let has_no_fields = self.r.field_names.get(&def_id).map_or(false, |f| f.is_empty());
1970 CtorKind::Const => false,
1971 CtorKind::Fn | CtorKind::Fictive if has_no_fields => false,
1976 let suggestable_variants = variants
1978 .filter(|(_, def_id, kind)| !needs_placeholder(*def_id, *kind))
1979 .map(|(variant, _, kind)| (path_names_to_string(variant), kind))
1980 .map(|(variant, kind)| match kind {
1981 CtorKind::Const => variant,
1982 CtorKind::Fn => format!("({}())", variant),
1983 CtorKind::Fictive => format!("({} {{}})", variant),
1985 .collect::<Vec<_>>();
1986 let no_suggestable_variant = suggestable_variants.is_empty();
1988 if !no_suggestable_variant {
1989 let msg = if suggestable_variants.len() == 1 {
1990 "you might have meant to use the following enum variant"
1992 "you might have meant to use one of the following enum variants"
1995 err.span_suggestions(
1998 suggestable_variants.into_iter(),
1999 Applicability::MaybeIncorrect,
2003 let suggestable_variants_with_placeholders = variants
2005 .filter(|(_, def_id, kind)| needs_placeholder(*def_id, *kind))
2006 .map(|(variant, _, kind)| (path_names_to_string(variant), kind))
2007 .filter_map(|(variant, kind)| match kind {
2008 CtorKind::Fn => Some(format!("({}(/* fields */))", variant)),
2009 CtorKind::Fictive => Some(format!("({} {{ /* fields */ }})", variant)),
2012 .collect::<Vec<_>>();
2014 if !suggestable_variants_with_placeholders.is_empty() {
2016 match (no_suggestable_variant, suggestable_variants_with_placeholders.len()) {
2017 (true, 1) => "the following enum variant is available",
2018 (true, _) => "the following enum variants are available",
2019 (false, 1) => "alternatively, the following enum variant is available",
2021 "alternatively, the following enum variants are also available"
2025 err.span_suggestions(
2028 suggestable_variants_with_placeholders.into_iter(),
2029 Applicability::HasPlaceholders,
2034 if def_id.is_local() {
2035 if let Some(span) = self.def_span(def_id) {
2036 err.span_note(span, "the enum is defined here");
2041 pub(crate) fn report_missing_type_error(
2044 ) -> Option<(Span, &'static str, String, Applicability)> {
2045 let (ident, span) = match path {
2046 [segment] if !segment.has_generic_args && segment.ident.name != kw::SelfUpper => {
2047 (segment.ident.to_string(), segment.ident.span)
2051 let mut iter = ident.chars().map(|c| c.is_uppercase());
2052 let single_uppercase_char =
2053 matches!(iter.next(), Some(true)) && matches!(iter.next(), None);
2054 if !self.diagnostic_metadata.currently_processing_generics && !single_uppercase_char {
2057 match (self.diagnostic_metadata.current_item, single_uppercase_char, self.diagnostic_metadata.currently_processing_generics) {
2058 (Some(Item { kind: ItemKind::Fn(..), ident, .. }), _, _) if ident.name == sym::main => {
2059 // Ignore `fn main()` as we don't want to suggest `fn main<T>()`
2064 kind @ ItemKind::Fn(..)
2065 | kind @ ItemKind::Enum(..)
2066 | kind @ ItemKind::Struct(..)
2067 | kind @ ItemKind::Union(..),
2072 // Without the 2nd `true`, we'd suggest `impl <T>` for `impl T` when a type `T` isn't found
2073 | (Some(Item { kind: kind @ ItemKind::Impl(..), .. }), true, true)
2074 | (Some(Item { kind, .. }), false, _) => {
2075 // Likely missing type parameter.
2076 if let Some(generics) = kind.generics() {
2077 if span.overlaps(generics.span) {
2078 // Avoid the following:
2079 // error[E0405]: cannot find trait `A` in this scope
2080 // --> $DIR/typo-suggestion-named-underscore.rs:CC:LL
2082 // L | fn foo<T: A>(x: T) {} // Shouldn't suggest underscore
2083 // | ^- help: you might be missing a type parameter: `, A`
2085 // | not found in this scope
2088 let msg = "you might be missing a type parameter";
2089 let (span, sugg) = if let [.., param] = &generics.params[..] {
2090 let span = if let [.., bound] = ¶m.bounds[..] {
2092 } else if let GenericParam {
2093 kind: GenericParamKind::Const { ty, kw_span: _, default }, ..
2095 default.as_ref().map(|def| def.value.span).unwrap_or(ty.span)
2099 (span, format!(", {}", ident))
2101 (generics.span, format!("<{}>", ident))
2103 // Do not suggest if this is coming from macro expansion.
2104 if span.can_be_used_for_suggestions() {
2106 span.shrink_to_hi(),
2109 Applicability::MaybeIncorrect,
2119 /// Given the target `label`, search the `rib_index`th label rib for similarly named labels,
2120 /// optionally returning the closest match and whether it is reachable.
2121 pub(crate) fn suggestion_for_label_in_rib(
2125 ) -> Option<LabelSuggestion> {
2126 // Are ribs from this `rib_index` within scope?
2127 let within_scope = self.is_label_valid_from_rib(rib_index);
2129 let rib = &self.label_ribs[rib_index];
2133 .filter(|(id, _)| id.span.eq_ctxt(label.span))
2134 .map(|(id, _)| id.name)
2135 .collect::<Vec<Symbol>>();
2137 find_best_match_for_name(&names, label.name, None).map(|symbol| {
2138 // Upon finding a similar name, get the ident that it was from - the span
2139 // contained within helps make a useful diagnostic. In addition, determine
2140 // whether this candidate is within scope.
2141 let (ident, _) = rib.bindings.iter().find(|(ident, _)| ident.name == symbol).unwrap();
2142 (*ident, within_scope)
2146 pub(crate) fn maybe_report_lifetime_uses(
2148 generics_span: Span,
2149 params: &[ast::GenericParam],
2151 for (param_index, param) in params.iter().enumerate() {
2152 let GenericParamKind::Lifetime = param.kind else { continue };
2154 let def_id = self.r.local_def_id(param.id);
2156 let use_set = self.lifetime_uses.remove(&def_id);
2158 "Use set for {:?}({:?} at {:?}) is {:?}",
2159 def_id, param.ident, param.ident.span, use_set
2162 let deletion_span = || {
2163 if params.len() == 1 {
2164 // if sole lifetime, remove the entire `<>` brackets
2166 } else if param_index == 0 {
2167 // if removing within `<>` brackets, we also want to
2168 // delete a leading or trailing comma as appropriate
2169 param.span().to(params[param_index + 1].span().shrink_to_lo())
2171 // if removing within `<>` brackets, we also want to
2172 // delete a leading or trailing comma as appropriate
2173 params[param_index - 1].span().shrink_to_hi().to(param.span())
2177 Some(LifetimeUseSet::Many) => {}
2178 Some(LifetimeUseSet::One { use_span, use_ctxt }) => {
2179 debug!(?param.ident, ?param.ident.span, ?use_span);
2181 let elidable = matches!(use_ctxt, LifetimeCtxt::Rptr);
2183 let deletion_span = deletion_span();
2184 self.r.lint_buffer.buffer_lint_with_diagnostic(
2185 lint::builtin::SINGLE_USE_LIFETIMES,
2188 &format!("lifetime parameter `{}` only used once", param.ident),
2189 lint::BuiltinLintDiagnostics::SingleUseLifetime {
2190 param_span: param.ident.span,
2191 use_span: Some((use_span, elidable)),
2197 debug!(?param.ident, ?param.ident.span);
2199 let deletion_span = deletion_span();
2200 self.r.lint_buffer.buffer_lint_with_diagnostic(
2201 lint::builtin::UNUSED_LIFETIMES,
2204 &format!("lifetime parameter `{}` never used", param.ident),
2205 lint::BuiltinLintDiagnostics::SingleUseLifetime {
2206 param_span: param.ident.span,
2216 pub(crate) fn emit_undeclared_lifetime_error(
2218 lifetime_ref: &ast::Lifetime,
2219 outer_lifetime_ref: Option<Ident>,
2221 debug_assert_ne!(lifetime_ref.ident.name, kw::UnderscoreLifetime);
2222 let mut err = if let Some(outer) = outer_lifetime_ref {
2223 let mut err = struct_span_err!(
2225 lifetime_ref.ident.span,
2227 "can't use generic parameters from outer item",
2229 err.span_label(lifetime_ref.ident.span, "use of generic parameter from outer item");
2230 err.span_label(outer.span, "lifetime parameter from outer item");
2233 let mut err = struct_span_err!(
2235 lifetime_ref.ident.span,
2237 "use of undeclared lifetime name `{}`",
2240 err.span_label(lifetime_ref.ident.span, "undeclared lifetime");
2243 self.suggest_introducing_lifetime(
2245 Some(lifetime_ref.ident.name.as_str()),
2246 |err, _, span, message, suggestion| {
2247 err.span_suggestion(span, message, suggestion, Applicability::MaybeIncorrect);
2254 fn suggest_introducing_lifetime(
2256 err: &mut Diagnostic,
2258 suggest: impl Fn(&mut Diagnostic, bool, Span, &str, String) -> bool,
2260 let mut suggest_note = true;
2261 for rib in self.lifetime_ribs.iter().rev() {
2262 let mut should_continue = true;
2264 LifetimeRibKind::Generics { binder: _, span, kind } => {
2265 if !span.can_be_used_for_suggestions() && suggest_note && let Some(name) = name {
2266 suggest_note = false; // Avoid displaying the same help multiple times.
2270 "lifetime `{}` is missing in item created through this procedural macro",
2277 let higher_ranked = matches!(
2279 LifetimeBinderKind::BareFnType
2280 | LifetimeBinderKind::PolyTrait
2281 | LifetimeBinderKind::WhereBound
2283 let (span, sugg) = if span.is_empty() {
2286 if higher_ranked { "for" } else { "" },
2287 name.unwrap_or("'a"),
2288 if higher_ranked { " " } else { "" },
2293 self.r.session.source_map().span_through_char(span, '<').shrink_to_hi();
2294 let sugg = format!("{}, ", name.unwrap_or("'a"));
2298 let message = format!(
2299 "consider making the {} lifetime-generic with a new `{}` lifetime",
2301 name.unwrap_or("'a"),
2303 should_continue = suggest(err, true, span, &message, sugg);
2305 "for more information on higher-ranked polymorphism, visit \
2306 https://doc.rust-lang.org/nomicon/hrtb.html",
2308 } else if let Some(name) = name {
2309 let message = format!("consider introducing lifetime `{}` here", name);
2310 should_continue = suggest(err, false, span, &message, sugg);
2312 let message = format!("consider introducing a named lifetime parameter");
2313 should_continue = suggest(err, false, span, &message, sugg);
2316 LifetimeRibKind::Item => break,
2319 if !should_continue {
2325 pub(crate) fn emit_non_static_lt_in_const_generic_error(&self, lifetime_ref: &ast::Lifetime) {
2328 lifetime_ref.ident.span,
2330 "use of non-static lifetime `{}` in const generic",
2334 "for more information, see issue #74052 \
2335 <https://github.com/rust-lang/rust/issues/74052>",
2340 /// Non-static lifetimes are prohibited in anonymous constants under `min_const_generics`.
2341 /// This function will emit an error if `generic_const_exprs` is not enabled, the body identified by
2342 /// `body_id` is an anonymous constant and `lifetime_ref` is non-static.
2343 pub(crate) fn maybe_emit_forbidden_non_static_lifetime_error(
2345 lifetime_ref: &ast::Lifetime,
2347 let feature_active = self.r.session.features_untracked().generic_const_exprs;
2348 if !feature_active {
2350 &self.r.session.parse_sess,
2351 sym::generic_const_exprs,
2352 lifetime_ref.ident.span,
2353 "a non-static lifetime is not allowed in a `const`",
2359 pub(crate) fn report_missing_lifetime_specifiers(
2361 lifetime_refs: Vec<MissingLifetime>,
2362 function_param_lifetimes: Option<(Vec<MissingLifetime>, Vec<ElisionFnParameter>)>,
2363 ) -> ErrorGuaranteed {
2364 let num_lifetimes: usize = lifetime_refs.iter().map(|lt| lt.count).sum();
2365 let spans: Vec<_> = lifetime_refs.iter().map(|lt| lt.span).collect();
2367 let mut err = struct_span_err!(
2371 "missing lifetime specifier{}",
2372 pluralize!(num_lifetimes)
2374 self.add_missing_lifetime_specifiers_label(
2377 function_param_lifetimes,
2382 fn add_missing_lifetime_specifiers_label(
2384 err: &mut Diagnostic,
2385 lifetime_refs: Vec<MissingLifetime>,
2386 function_param_lifetimes: Option<(Vec<MissingLifetime>, Vec<ElisionFnParameter>)>,
2388 for < in &lifetime_refs {
2392 "expected {} lifetime parameter{}",
2393 if lt.count == 1 { "named".to_string() } else { lt.count.to_string() },
2394 pluralize!(lt.count),
2399 let mut in_scope_lifetimes: Vec<_> = self
2403 .take_while(|rib| !matches!(rib.kind, LifetimeRibKind::Item))
2404 .flat_map(|rib| rib.bindings.iter())
2405 .map(|(&ident, &res)| (ident, res))
2406 .filter(|(ident, _)| ident.name != kw::UnderscoreLifetime)
2408 debug!(?in_scope_lifetimes);
2410 debug!(?function_param_lifetimes);
2411 if let Some((param_lifetimes, params)) = &function_param_lifetimes {
2412 let elided_len = param_lifetimes.len();
2413 let num_params = params.len();
2415 let mut m = String::new();
2417 for (i, info) in params.iter().enumerate() {
2418 let ElisionFnParameter { ident, index, lifetime_count, span } = *info;
2419 debug_assert_ne!(lifetime_count, 0);
2421 err.span_label(span, "");
2424 if i + 1 < num_params {
2426 } else if num_params == 2 {
2429 m.push_str(", or ");
2433 let help_name = if let Some(ident) = ident {
2434 format!("`{}`", ident)
2436 format!("argument {}", index + 1)
2439 if lifetime_count == 1 {
2440 m.push_str(&help_name[..])
2442 m.push_str(&format!("one of {}'s {} lifetimes", help_name, lifetime_count)[..])
2446 if num_params == 0 {
2448 "this function's return type contains a borrowed value, \
2449 but there is no value for it to be borrowed from",
2451 if in_scope_lifetimes.is_empty() {
2452 in_scope_lifetimes = vec![(
2453 Ident::with_dummy_span(kw::StaticLifetime),
2454 (DUMMY_NODE_ID, LifetimeRes::Static),
2457 } else if elided_len == 0 {
2459 "this function's return type contains a borrowed value with \
2460 an elided lifetime, but the lifetime cannot be derived from \
2463 if in_scope_lifetimes.is_empty() {
2464 in_scope_lifetimes = vec![(
2465 Ident::with_dummy_span(kw::StaticLifetime),
2466 (DUMMY_NODE_ID, LifetimeRes::Static),
2469 } else if num_params == 1 {
2471 "this function's return type contains a borrowed value, \
2472 but the signature does not say which {} it is borrowed from",
2477 "this function's return type contains a borrowed value, \
2478 but the signature does not say whether it is borrowed from {}",
2484 let existing_name = match &in_scope_lifetimes[..] {
2485 [] => Symbol::intern("'a"),
2486 [(existing, _)] => existing.name,
2487 _ => Symbol::intern("'lifetime"),
2490 let mut spans_suggs: Vec<_> = Vec::new();
2491 let build_sugg = |lt: MissingLifetime| match lt.kind {
2492 MissingLifetimeKind::Underscore => {
2493 debug_assert_eq!(lt.count, 1);
2494 (lt.span, existing_name.to_string())
2496 MissingLifetimeKind::Ampersand => {
2497 debug_assert_eq!(lt.count, 1);
2498 (lt.span.shrink_to_hi(), format!("{} ", existing_name))
2500 MissingLifetimeKind::Comma => {
2501 let sugg: String = std::iter::repeat([existing_name.as_str(), ", "])
2505 (lt.span.shrink_to_hi(), sugg)
2507 MissingLifetimeKind::Brackets => {
2508 let sugg: String = std::iter::once("<")
2510 std::iter::repeat(existing_name.as_str()).take(lt.count).intersperse(", "),
2514 (lt.span.shrink_to_hi(), sugg)
2517 for < in &lifetime_refs {
2518 spans_suggs.push(build_sugg(lt));
2520 debug!(?spans_suggs);
2521 match in_scope_lifetimes.len() {
2523 if let Some((param_lifetimes, _)) = function_param_lifetimes {
2524 for lt in param_lifetimes {
2525 spans_suggs.push(build_sugg(lt))
2528 self.suggest_introducing_lifetime(
2531 |err, higher_ranked, span, message, intro_sugg| {
2532 err.multipart_suggestion_verbose(
2534 std::iter::once((span, intro_sugg))
2535 .chain(spans_suggs.iter().cloned())
2537 Applicability::MaybeIncorrect,
2544 err.multipart_suggestion_verbose(
2545 &format!("consider using the `{}` lifetime", existing_name),
2547 Applicability::MaybeIncorrect,
2550 // Record as using the suggested resolution.
2551 let (_, (_, res)) = in_scope_lifetimes[0];
2552 for < in &lifetime_refs {
2553 self.r.lifetimes_res_map.insert(lt.id, res);
2557 let lifetime_spans: Vec<_> =
2558 in_scope_lifetimes.iter().map(|(ident, _)| ident.span).collect();
2559 err.span_note(lifetime_spans, "these named lifetimes are available to use");
2561 if spans_suggs.len() > 0 {
2562 // This happens when we have `Foo<T>` where we point at the space before `T`,
2563 // but this can be confusing so we give a suggestion with placeholders.
2564 err.multipart_suggestion_verbose(
2565 "consider using one of the available lifetimes here",
2567 Applicability::HasPlaceholders,
2575 /// Report lifetime/lifetime shadowing as an error.
2576 pub fn signal_lifetime_shadowing(sess: &Session, orig: Ident, shadower: Ident) {
2577 let mut err = struct_span_err!(
2581 "lifetime name `{}` shadows a lifetime name that is already in scope",
2584 err.span_label(orig.span, "first declared here");
2585 err.span_label(shadower.span, format!("lifetime `{}` already in scope", orig.name));
2589 /// Shadowing involving a label is only a warning for historical reasons.
2590 //FIXME: make this a proper lint.
2591 pub fn signal_label_shadowing(sess: &Session, orig: Span, shadower: Ident) {
2592 let name = shadower.name;
2593 let shadower = shadower.span;
2594 let mut err = sess.struct_span_warn(
2596 &format!("label name `{}` shadows a label name that is already in scope", name),
2598 err.span_label(orig, "first declared here");
2599 err.span_label(shadower, format!("label `{}` already in scope", name));