4 use rustc_ast::visit::{self, Visitor};
5 use rustc_ast::{self as ast, Crate, ItemKind, ModKind, NodeId, Path, CRATE_NODE_ID};
6 use rustc_ast_pretty::pprust;
7 use rustc_data_structures::fx::FxHashSet;
8 use rustc_errors::struct_span_err;
9 use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, MultiSpan};
10 use rustc_feature::BUILTIN_ATTRIBUTES;
11 use rustc_hir::def::Namespace::{self, *};
12 use rustc_hir::def::{self, CtorKind, CtorOf, DefKind, NonMacroAttrKind, PerNS};
13 use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID, LOCAL_CRATE};
14 use rustc_hir::PrimTy;
15 use rustc_index::vec::IndexVec;
16 use rustc_middle::bug;
17 use rustc_middle::ty::DefIdTree;
18 use rustc_session::lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE;
19 use rustc_session::lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS;
20 use rustc_session::lint::BuiltinLintDiagnostics;
21 use rustc_session::Session;
22 use rustc_span::edition::Edition;
23 use rustc_span::hygiene::MacroKind;
24 use rustc_span::lev_distance::find_best_match_for_name;
25 use rustc_span::source_map::SourceMap;
26 use rustc_span::symbol::{kw, sym, Ident, Symbol};
27 use rustc_span::{BytePos, Span};
30 use crate::imports::{Import, ImportKind, ImportResolver};
31 use crate::late::{PatternSource, Rib};
32 use crate::path_names_to_string;
33 use crate::{AmbiguityError, AmbiguityErrorMisc, AmbiguityKind, BindingError, Finalize};
34 use crate::{HasGenericParams, MacroRulesScope, Module, ModuleKind, ModuleOrUniformRoot};
35 use crate::{LexicalScopeBinding, NameBinding, NameBindingKind, PrivacyError, VisResolutionError};
36 use crate::{ParentScope, PathResult, ResolutionError, Resolver, Scope, ScopeSet};
37 use crate::{Segment, UseError};
42 type Res = def::Res<ast::NodeId>;
44 /// A vector of spans and replacements, a message and applicability.
45 pub(crate) type Suggestion = (Vec<(Span, String)>, String, Applicability);
47 /// Potential candidate for an undeclared or out-of-scope label - contains the ident of a
48 /// similarly named label and whether or not it is reachable.
49 pub(crate) type LabelSuggestion = (Ident, bool);
51 pub(crate) enum SuggestionTarget {
52 /// The target has a similar name as the name used by the programmer (probably a typo)
54 /// The target is the only valid item that can be used in the corresponding context
58 pub(crate) struct TypoSuggestion {
59 pub candidate: Symbol,
61 pub target: SuggestionTarget,
65 pub(crate) fn typo_from_res(candidate: Symbol, res: Res) -> TypoSuggestion {
66 Self { candidate, res, target: SuggestionTarget::SimilarlyNamed }
68 pub(crate) fn single_item_from_res(candidate: Symbol, res: Res) -> TypoSuggestion {
69 Self { candidate, res, target: SuggestionTarget::SingleItem }
73 /// A free importable items suggested in case of resolution failure.
74 pub(crate) struct ImportSuggestion {
75 pub did: Option<DefId>,
76 pub descr: &'static str,
79 /// An extra note that should be issued if this item is suggested
80 pub note: Option<String>,
83 /// Adjust the impl span so that just the `impl` keyword is taken by removing
84 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
85 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`).
87 /// *Attention*: the method used is very fragile since it essentially duplicates the work of the
88 /// parser. If you need to use this function or something similar, please consider updating the
89 /// `source_map` functions and this function to something more robust.
90 fn reduce_impl_span_to_impl_keyword(sm: &SourceMap, impl_span: Span) -> Span {
91 let impl_span = sm.span_until_char(impl_span, '<');
92 sm.span_until_whitespace(impl_span)
95 impl<'a> Resolver<'a> {
96 pub(crate) fn report_errors(&mut self, krate: &Crate) {
97 self.report_with_use_injections(krate);
99 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
100 let msg = "macro-expanded `macro_export` macros from the current crate \
101 cannot be referred to by absolute paths";
102 self.lint_buffer.buffer_lint_with_diagnostic(
103 MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
107 BuiltinLintDiagnostics::MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
111 for ambiguity_error in &self.ambiguity_errors {
112 self.report_ambiguity_error(ambiguity_error);
115 let mut reported_spans = FxHashSet::default();
116 for error in &self.privacy_errors {
117 if reported_spans.insert(error.dedup_span) {
118 self.report_privacy_error(error);
123 fn report_with_use_injections(&mut self, krate: &Crate) {
124 for UseError { mut err, candidates, def_id, instead, suggestion, path } in
125 self.use_injections.drain(..)
127 let (span, found_use) = if let Some(def_id) = def_id.as_local() {
128 UsePlacementFinder::check(krate, self.def_id_to_node_id[def_id])
132 if !candidates.is_empty() {
139 if instead { Instead::Yes } else { Instead::No },
144 } else if let Some((span, msg, sugg, appl)) = suggestion {
145 err.span_suggestion(span, msg, sugg, appl);
151 pub(crate) fn report_conflict<'b>(
156 new_binding: &NameBinding<'b>,
157 old_binding: &NameBinding<'b>,
159 // Error on the second of two conflicting names
160 if old_binding.span.lo() > new_binding.span.lo() {
161 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
164 let container = match parent.kind {
165 ModuleKind::Def(kind, _, _) => kind.descr(parent.def_id()),
166 ModuleKind::Block => "block",
169 let old_noun = match old_binding.is_import() {
171 false => "definition",
174 let new_participle = match new_binding.is_import() {
180 (ident.name, self.session.source_map().guess_head_span(new_binding.span));
182 if let Some(s) = self.name_already_seen.get(&name) {
188 let old_kind = match (ns, old_binding.module()) {
189 (ValueNS, _) => "value",
190 (MacroNS, _) => "macro",
191 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
192 (TypeNS, Some(module)) if module.is_normal() => "module",
193 (TypeNS, Some(module)) if module.is_trait() => "trait",
194 (TypeNS, _) => "type",
197 let msg = format!("the name `{}` is defined multiple times", name);
199 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
200 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
201 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
202 true => struct_span_err!(self.session, span, E0254, "{}", msg),
203 false => struct_span_err!(self.session, span, E0260, "{}", msg),
205 _ => match (old_binding.is_import(), new_binding.is_import()) {
206 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
207 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
208 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
213 "`{}` must be defined only once in the {} namespace of this {}",
219 err.span_label(span, format!("`{}` re{} here", name, new_participle));
221 self.session.source_map().guess_head_span(old_binding.span),
222 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
225 // See https://github.com/rust-lang/rust/issues/32354
226 use NameBindingKind::Import;
227 let import = match (&new_binding.kind, &old_binding.kind) {
228 // If there are two imports where one or both have attributes then prefer removing the
229 // import without attributes.
230 (Import { import: new, .. }, Import { import: old, .. })
232 !new_binding.span.is_dummy()
233 && !old_binding.span.is_dummy()
234 && (new.has_attributes || old.has_attributes)
237 if old.has_attributes {
238 Some((new, new_binding.span, true))
240 Some((old, old_binding.span, true))
243 // Otherwise prioritize the new binding.
244 (Import { import, .. }, other) if !new_binding.span.is_dummy() => {
245 Some((import, new_binding.span, other.is_import()))
247 (other, Import { import, .. }) if !old_binding.span.is_dummy() => {
248 Some((import, old_binding.span, other.is_import()))
253 // Check if the target of the use for both bindings is the same.
254 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
255 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
257 self.extern_prelude.get(&ident).map_or(true, |entry| entry.introduced_by_item);
258 // Only suggest removing an import if both bindings are to the same def, if both spans
259 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
260 // been introduced by an item.
261 let should_remove_import = duplicate
263 && ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
266 Some((import, span, true)) if should_remove_import && import.is_nested() => {
267 self.add_suggestion_for_duplicate_nested_use(&mut err, import, span)
269 Some((import, _, true)) if should_remove_import && !import.is_glob() => {
270 // Simple case - remove the entire import. Due to the above match arm, this can
271 // only be a single use so just remove it entirely.
272 err.tool_only_span_suggestion(
273 import.use_span_with_attributes,
274 "remove unnecessary import",
276 Applicability::MaybeIncorrect,
279 Some((import, span, _)) => {
280 self.add_suggestion_for_rename_of_use(&mut err, name, import, span)
286 self.name_already_seen.insert(name, span);
289 /// This function adds a suggestion to change the binding name of a new import that conflicts
290 /// with an existing import.
292 /// ```text,ignore (diagnostic)
293 /// help: you can use `as` to change the binding name of the import
295 /// LL | use foo::bar as other_bar;
296 /// | ^^^^^^^^^^^^^^^^^^^^^
298 fn add_suggestion_for_rename_of_use(
300 err: &mut Diagnostic,
305 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
306 format!("Other{}", name)
308 format!("other_{}", name)
311 let mut suggestion = None;
313 ImportKind::Single { type_ns_only: true, .. } => {
314 suggestion = Some(format!("self as {}", suggested_name))
316 ImportKind::Single { source, .. } => {
318 source.span.hi().0.checked_sub(binding_span.lo().0).map(|pos| pos as usize)
320 if let Ok(snippet) = self.session.source_map().span_to_snippet(binding_span) {
321 if pos <= snippet.len() {
322 suggestion = Some(format!(
326 if snippet.ends_with(';') { ";" } else { "" }
332 ImportKind::ExternCrate { source, target } => {
333 suggestion = Some(format!(
334 "extern crate {} as {};",
335 source.unwrap_or(target.name),
342 let rename_msg = "you can use `as` to change the binding name of the import";
343 if let Some(suggestion) = suggestion {
348 Applicability::MaybeIncorrect,
351 err.span_label(binding_span, rename_msg);
355 /// This function adds a suggestion to remove an unnecessary binding from an import that is
356 /// nested. In the following example, this function will be invoked to remove the `a` binding
357 /// in the second use statement:
359 /// ```ignore (diagnostic)
360 /// use issue_52891::a;
361 /// use issue_52891::{d, a, e};
364 /// The following suggestion will be added:
366 /// ```ignore (diagnostic)
367 /// use issue_52891::{d, a, e};
368 /// ^-- help: remove unnecessary import
371 /// If the nested use contains only one import then the suggestion will remove the entire
374 /// It is expected that the provided import is nested - this isn't checked by the
375 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
376 /// as characters expected by span manipulations won't be present.
377 fn add_suggestion_for_duplicate_nested_use(
379 err: &mut Diagnostic,
383 assert!(import.is_nested());
384 let message = "remove unnecessary import";
386 // Two examples will be used to illustrate the span manipulations we're doing:
388 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
389 // `a` and `import.use_span` is `issue_52891::{d, a, e};`.
390 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
391 // `a` and `import.use_span` is `issue_52891::{d, e, a};`.
393 let (found_closing_brace, span) =
394 find_span_of_binding_until_next_binding(self.session, binding_span, import.use_span);
396 // If there was a closing brace then identify the span to remove any trailing commas from
398 if found_closing_brace {
399 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
400 err.tool_only_span_suggestion(span, message, "", Applicability::MaybeIncorrect);
402 // Remove the entire line if we cannot extend the span back, this indicates an
403 // `issue_52891::{self}` case.
405 import.use_span_with_attributes,
408 Applicability::MaybeIncorrect,
415 err.span_suggestion(span, message, "", Applicability::MachineApplicable);
418 pub(crate) fn lint_if_path_starts_with_module(
420 finalize: Option<Finalize>,
422 second_binding: Option<&NameBinding<'_>>,
424 let Some(Finalize { node_id, root_span, .. }) = finalize else {
428 let first_name = match path.get(0) {
429 // In the 2018 edition this lint is a hard error, so nothing to do
430 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
434 // We're only interested in `use` paths which should start with
435 // `{{root}}` currently.
436 if first_name != kw::PathRoot {
441 // If this import looks like `crate::...` it's already good
442 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
443 // Otherwise go below to see if it's an extern crate
445 // If the path has length one (and it's `PathRoot` most likely)
446 // then we don't know whether we're gonna be importing a crate or an
447 // item in our crate. Defer this lint to elsewhere
451 // If the first element of our path was actually resolved to an
452 // `ExternCrate` (also used for `crate::...`) then no need to issue a
453 // warning, this looks all good!
454 if let Some(binding) = second_binding {
455 if let NameBindingKind::Import { import, .. } = binding.kind {
456 // Careful: we still want to rewrite paths from renamed extern crates.
457 if let ImportKind::ExternCrate { source: None, .. } = import.kind {
463 let diag = BuiltinLintDiagnostics::AbsPathWithModule(root_span);
464 self.lint_buffer.buffer_lint_with_diagnostic(
465 ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
468 "absolute paths must start with `self`, `super`, \
469 `crate`, or an external crate name in the 2018 edition",
474 pub(crate) fn add_module_candidates(
477 names: &mut Vec<TypoSuggestion>,
478 filter_fn: &impl Fn(Res) -> bool,
480 for (key, resolution) in self.resolutions(module).borrow().iter() {
481 if let Some(binding) = resolution.borrow().binding {
482 let res = binding.res();
484 names.push(TypoSuggestion::typo_from_res(key.ident.name, res));
490 /// Combines an error with provided span and emits it.
492 /// This takes the error provided, combines it with the span and any additional spans inside the
493 /// error and emits it.
494 pub(crate) fn report_error(&mut self, span: Span, resolution_error: ResolutionError<'a>) {
495 self.into_struct_error(span, resolution_error).emit();
498 pub(crate) fn into_struct_error(
501 resolution_error: ResolutionError<'a>,
502 ) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
503 match resolution_error {
504 ResolutionError::GenericParamsFromOuterFunction(outer_res, has_generic_params) => {
505 let mut err = struct_span_err!(
509 "can't use generic parameters from outer function",
511 err.span_label(span, "use of generic parameter from outer function");
513 let sm = self.session.source_map();
514 let def_id = match outer_res {
515 Res::SelfTy { trait_: maybe_trait_defid, alias_to: maybe_impl_defid } => {
516 if let Some(impl_span) =
517 maybe_impl_defid.and_then(|(def_id, _)| self.opt_span(def_id))
520 reduce_impl_span_to_impl_keyword(sm, impl_span),
521 "`Self` type implicitly declared here, by this `impl`",
524 match (maybe_trait_defid, maybe_impl_defid) {
526 err.span_label(span, "can't use `Self` here");
529 err.span_label(span, "use a type here instead");
531 (None, None) => bug!("`impl` without trait nor type?"),
535 Res::Def(DefKind::TyParam, def_id) => {
536 if let Some(span) = self.opt_span(def_id) {
537 err.span_label(span, "type parameter from outer function");
541 Res::Def(DefKind::ConstParam, def_id) => {
542 if let Some(span) = self.opt_span(def_id) {
543 err.span_label(span, "const parameter from outer function");
549 "GenericParamsFromOuterFunction should only be used with Res::SelfTy, \
550 DefKind::TyParam or DefKind::ConstParam"
555 if let HasGenericParams::Yes(span) = has_generic_params {
556 // Try to retrieve the span of the function signature and generate a new
557 // message with a local type or const parameter.
558 let sugg_msg = "try using a local generic parameter instead";
559 let name = self.opt_name(def_id).unwrap_or(sym::T);
560 let (span, snippet) = if span.is_empty() {
561 let snippet = format!("<{}>", name);
564 let span = sm.span_through_char(span, '<').shrink_to_hi();
565 let snippet = format!("{}, ", name);
568 // Suggest the modification to the user
569 err.span_suggestion(span, sugg_msg, snippet, Applicability::MaybeIncorrect);
574 ResolutionError::NameAlreadyUsedInParameterList(name, first_use_span) => {
575 let mut err = struct_span_err!(
579 "the name `{}` is already used for a generic \
580 parameter in this item's generic parameters",
583 err.span_label(span, "already used");
584 err.span_label(first_use_span, format!("first use of `{}`", name));
587 ResolutionError::MethodNotMemberOfTrait(method, trait_, candidate) => {
588 let mut err = struct_span_err!(
592 "method `{}` is not a member of trait `{}`",
596 err.span_label(span, format!("not a member of trait `{}`", trait_));
597 if let Some(candidate) = candidate {
600 "there is an associated function with a similar name",
601 candidate.to_ident_string(),
602 Applicability::MaybeIncorrect,
607 ResolutionError::TypeNotMemberOfTrait(type_, trait_, candidate) => {
608 let mut err = struct_span_err!(
612 "type `{}` is not a member of trait `{}`",
616 err.span_label(span, format!("not a member of trait `{}`", trait_));
617 if let Some(candidate) = candidate {
620 "there is an associated type with a similar name",
621 candidate.to_ident_string(),
622 Applicability::MaybeIncorrect,
627 ResolutionError::ConstNotMemberOfTrait(const_, trait_, candidate) => {
628 let mut err = struct_span_err!(
632 "const `{}` is not a member of trait `{}`",
636 err.span_label(span, format!("not a member of trait `{}`", trait_));
637 if let Some(candidate) = candidate {
640 "there is an associated constant with a similar name",
641 candidate.to_ident_string(),
642 Applicability::MaybeIncorrect,
647 ResolutionError::VariableNotBoundInPattern(binding_error, parent_scope) => {
648 let BindingError { name, target, origin, could_be_path } = binding_error;
650 let target_sp = target.iter().copied().collect::<Vec<_>>();
651 let origin_sp = origin.iter().copied().collect::<Vec<_>>();
653 let msp = MultiSpan::from_spans(target_sp.clone());
654 let mut err = struct_span_err!(
658 "variable `{}` is not bound in all patterns",
661 for sp in target_sp {
662 err.span_label(sp, format!("pattern doesn't bind `{}`", name));
664 for sp in origin_sp {
665 err.span_label(sp, "variable not in all patterns");
668 let import_suggestions = self.lookup_import_candidates(
669 Ident::with_dummy_span(name),
672 &|res: Res| match res {
674 DefKind::Ctor(CtorOf::Variant, CtorKind::Const)
675 | DefKind::Ctor(CtorOf::Struct, CtorKind::Const)
677 | DefKind::AssocConst,
684 if import_suggestions.is_empty() {
685 let help_msg = format!(
686 "if you meant to match on a variant or a `const` item, consider \
687 making the path in the pattern qualified: `path::to::ModOrType::{}`",
690 err.span_help(span, &help_msg);
706 ResolutionError::VariableBoundWithDifferentMode(variable_name, first_binding_span) => {
707 let mut err = struct_span_err!(
711 "variable `{}` is bound inconsistently across alternatives separated by `|`",
714 err.span_label(span, "bound in different ways");
715 err.span_label(first_binding_span, "first binding");
718 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
719 let mut err = struct_span_err!(
723 "identifier `{}` is bound more than once in this parameter list",
726 err.span_label(span, "used as parameter more than once");
729 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
730 let mut err = struct_span_err!(
734 "identifier `{}` is bound more than once in the same pattern",
737 err.span_label(span, "used in a pattern more than once");
740 ResolutionError::UndeclaredLabel { name, suggestion } => {
741 let mut err = struct_span_err!(
745 "use of undeclared label `{}`",
749 err.span_label(span, format!("undeclared label `{}`", name));
752 // A reachable label with a similar name exists.
753 Some((ident, true)) => {
754 err.span_label(ident.span, "a label with a similar name is reachable");
757 "try using similarly named label",
759 Applicability::MaybeIncorrect,
762 // An unreachable label with a similar name exists.
763 Some((ident, false)) => {
766 "a label with a similar name exists but is unreachable",
769 // No similarly-named labels exist.
775 ResolutionError::SelfImportsOnlyAllowedWithin { root, span_with_rename } => {
776 let mut err = struct_span_err!(
781 "`self` imports are only allowed within a { } list"
784 // None of the suggestions below would help with a case like `use self`.
786 // use foo::bar::self -> foo::bar
787 // use foo::bar::self as abc -> foo::bar as abc
790 "consider importing the module directly",
792 Applicability::MachineApplicable,
795 // use foo::bar::self -> foo::bar::{self}
796 // use foo::bar::self as abc -> foo::bar::{self as abc}
798 (span_with_rename.shrink_to_lo(), "{".to_string()),
799 (span_with_rename.shrink_to_hi(), "}".to_string()),
801 err.multipart_suggestion(
802 "alternatively, use the multi-path `use` syntax to import `self`",
804 Applicability::MachineApplicable,
809 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
810 let mut err = struct_span_err!(
814 "`self` import can only appear once in an import list"
816 err.span_label(span, "can only appear once in an import list");
819 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
820 let mut err = struct_span_err!(
824 "`self` import can only appear in an import list with \
827 err.span_label(span, "can only appear in an import list with a non-empty prefix");
830 ResolutionError::FailedToResolve { label, suggestion } => {
832 struct_span_err!(self.session, span, E0433, "failed to resolve: {}", &label);
833 err.span_label(span, label);
835 if let Some((suggestions, msg, applicability)) = suggestion {
836 if suggestions.is_empty() {
840 err.multipart_suggestion(&msg, suggestions, applicability);
845 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
846 let mut err = struct_span_err!(
851 "can't capture dynamic environment in a fn item"
853 err.help("use the `|| { ... }` closure form instead");
856 ResolutionError::AttemptToUseNonConstantValueInConstant(ident, sugg, current) => {
857 let mut err = struct_span_err!(
861 "attempt to use a non-constant value in a constant"
864 // ^^^ given this Span
865 // ------- get this Span to have an applicable suggestion
868 // only do this if the const and usage of the non-constant value are on the same line
869 // the further the two are apart, the higher the chance of the suggestion being wrong
874 .span_extend_to_prev_str(ident.span, current, true, false);
877 Some(sp) if !self.session.source_map().is_multiline(sp) => {
878 let sp = sp.with_lo(BytePos(sp.lo().0 - (current.len() as u32)));
881 &format!("consider using `{}` instead of `{}`", sugg, current),
882 format!("{} {}", sugg, ident),
883 Applicability::MaybeIncorrect,
885 err.span_label(span, "non-constant value");
888 err.span_label(ident.span, &format!("this would need to be a `{}`", sugg));
894 ResolutionError::BindingShadowsSomethingUnacceptable {
900 shadowed_binding_span,
902 let shadowed_binding_descr = shadowed_binding.descr();
903 let mut err = struct_span_err!(
907 "{}s cannot shadow {}s",
908 shadowing_binding.descr(),
909 shadowed_binding_descr,
913 format!("cannot be named the same as {} {}", article, shadowed_binding_descr),
915 match (shadowing_binding, shadowed_binding) {
917 PatternSource::Match,
918 Res::Def(DefKind::Ctor(CtorOf::Variant | CtorOf::Struct, CtorKind::Fn), _),
922 "try specify the pattern arguments",
923 format!("{}(..)", name),
924 Applicability::Unspecified,
930 format!("the {} `{}` is {} here", shadowed_binding_descr, name, participle);
931 err.span_label(shadowed_binding_span, msg);
934 ResolutionError::ForwardDeclaredGenericParam => {
935 let mut err = struct_span_err!(
939 "generic parameters with a default cannot use \
940 forward declared identifiers"
942 err.span_label(span, "defaulted generic parameters cannot be forward declared");
945 ResolutionError::ParamInTyOfConstParam(name) => {
946 let mut err = struct_span_err!(
950 "the type of const parameters must not depend on other generic parameters"
954 format!("the type must not depend on the parameter `{}`", name),
958 ResolutionError::ParamInNonTrivialAnonConst { name, is_type } => {
959 let mut err = self.session.struct_span_err(
961 "generic parameters may not be used in const operations",
963 err.span_label(span, &format!("cannot perform const operation using `{}`", name));
966 err.note("type parameters may not be used in const expressions");
969 "const parameters may only be used as standalone arguments, i.e. `{}`",
974 if self.session.is_nightly_build() {
976 "use `#![feature(generic_const_exprs)]` to allow generic const expressions",
982 ResolutionError::SelfInGenericParamDefault => {
983 let mut err = struct_span_err!(
987 "generic parameters cannot use `Self` in their defaults"
989 err.span_label(span, "`Self` in generic parameter default");
992 ResolutionError::UnreachableLabel { name, definition_span, suggestion } => {
993 let mut err = struct_span_err!(
997 "use of unreachable label `{}`",
1001 err.span_label(definition_span, "unreachable label defined here");
1002 err.span_label(span, format!("unreachable label `{}`", name));
1004 "labels are unreachable through functions, closures, async blocks and modules",
1008 // A reachable label with a similar name exists.
1009 Some((ident, true)) => {
1010 err.span_label(ident.span, "a label with a similar name is reachable");
1011 err.span_suggestion(
1013 "try using similarly named label",
1015 Applicability::MaybeIncorrect,
1018 // An unreachable label with a similar name exists.
1019 Some((ident, false)) => {
1022 "a label with a similar name exists but is also unreachable",
1025 // No similarly-named labels exist.
1031 ResolutionError::TraitImplMismatch {
1038 let mut err = self.session.struct_span_err_with_code(
1041 "item `{}` is an associated {}, which doesn't match its trait `{}`",
1042 name, kind, trait_path,
1046 err.span_label(span, "does not match trait");
1047 err.span_label(trait_item_span, "item in trait");
1050 ResolutionError::InvalidAsmSym => {
1051 let mut err = self.session.struct_span_err(span, "invalid `sym` operand");
1052 err.span_label(span, "is a local variable");
1053 err.help("`sym` operands must refer to either a function or a static");
1059 pub(crate) fn report_vis_error(
1061 vis_resolution_error: VisResolutionError<'_>,
1062 ) -> ErrorGuaranteed {
1063 match vis_resolution_error {
1064 VisResolutionError::Relative2018(span, path) => {
1065 let mut err = self.session.struct_span_err(
1067 "relative paths are not supported in visibilities in 2018 edition or later",
1069 err.span_suggestion(
1072 format!("crate::{}", pprust::path_to_string(&path)),
1073 Applicability::MaybeIncorrect,
1077 VisResolutionError::AncestorOnly(span) => struct_span_err!(
1081 "visibilities can only be restricted to ancestor modules"
1083 VisResolutionError::FailedToResolve(span, label, suggestion) => {
1084 self.into_struct_error(span, ResolutionError::FailedToResolve { label, suggestion })
1086 VisResolutionError::ExpectedFound(span, path_str, res) => {
1087 let mut err = struct_span_err!(
1091 "expected module, found {} `{}`",
1095 err.span_label(span, "not a module");
1098 VisResolutionError::Indeterminate(span) => struct_span_err!(
1102 "cannot determine resolution for the visibility"
1104 VisResolutionError::ModuleOnly(span) => {
1105 self.session.struct_span_err(span, "visibility must resolve to a module")
1111 /// Lookup typo candidate in scope for a macro or import.
1112 fn early_lookup_typo_candidate(
1114 scope_set: ScopeSet<'a>,
1115 parent_scope: &ParentScope<'a>,
1117 filter_fn: &impl Fn(Res) -> bool,
1118 ) -> Option<TypoSuggestion> {
1119 let mut suggestions = Vec::new();
1120 let ctxt = ident.span.ctxt();
1121 self.visit_scopes(scope_set, parent_scope, ctxt, |this, scope, use_prelude, _| {
1123 Scope::DeriveHelpers(expn_id) => {
1124 let res = Res::NonMacroAttr(NonMacroAttrKind::DeriveHelper);
1131 .map(|ident| TypoSuggestion::typo_from_res(ident.name, res)),
1135 Scope::DeriveHelpersCompat => {
1136 let res = Res::NonMacroAttr(NonMacroAttrKind::DeriveHelperCompat);
1138 for derive in parent_scope.derives {
1139 let parent_scope = &ParentScope { derives: &[], ..*parent_scope };
1140 if let Ok((Some(ext), _)) = this.resolve_macro_path(
1142 Some(MacroKind::Derive),
1150 .map(|name| TypoSuggestion::typo_from_res(*name, res)),
1156 Scope::MacroRules(macro_rules_scope) => {
1157 if let MacroRulesScope::Binding(macro_rules_binding) = macro_rules_scope.get() {
1158 let res = macro_rules_binding.binding.res();
1160 suggestions.push(TypoSuggestion::typo_from_res(
1161 macro_rules_binding.ident.name,
1167 Scope::CrateRoot => {
1168 let root_ident = Ident::new(kw::PathRoot, ident.span);
1169 let root_module = this.resolve_crate_root(root_ident);
1170 this.add_module_candidates(root_module, &mut suggestions, filter_fn);
1172 Scope::Module(module, _) => {
1173 this.add_module_candidates(module, &mut suggestions, filter_fn);
1175 Scope::MacroUsePrelude => {
1176 suggestions.extend(this.macro_use_prelude.iter().filter_map(
1178 let res = binding.res();
1179 filter_fn(res).then_some(TypoSuggestion::typo_from_res(*name, res))
1183 Scope::BuiltinAttrs => {
1184 let res = Res::NonMacroAttr(NonMacroAttrKind::Builtin(kw::Empty));
1189 .map(|attr| TypoSuggestion::typo_from_res(attr.name, res)),
1193 Scope::ExternPrelude => {
1194 suggestions.extend(this.extern_prelude.iter().filter_map(|(ident, _)| {
1195 let res = Res::Def(DefKind::Mod, CRATE_DEF_ID.to_def_id());
1196 filter_fn(res).then_some(TypoSuggestion::typo_from_res(ident.name, res))
1199 Scope::ToolPrelude => {
1200 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
1202 this.registered_tools
1204 .map(|ident| TypoSuggestion::typo_from_res(ident.name, res)),
1207 Scope::StdLibPrelude => {
1208 if let Some(prelude) = this.prelude {
1209 let mut tmp_suggestions = Vec::new();
1210 this.add_module_candidates(prelude, &mut tmp_suggestions, filter_fn);
1214 .filter(|s| use_prelude || this.is_builtin_macro(s.res)),
1218 Scope::BuiltinTypes => {
1219 suggestions.extend(PrimTy::ALL.iter().filter_map(|prim_ty| {
1220 let res = Res::PrimTy(*prim_ty);
1221 filter_fn(res).then_some(TypoSuggestion::typo_from_res(prim_ty.name(), res))
1229 // Make sure error reporting is deterministic.
1230 suggestions.sort_by(|a, b| a.candidate.as_str().partial_cmp(b.candidate.as_str()).unwrap());
1232 match find_best_match_for_name(
1233 &suggestions.iter().map(|suggestion| suggestion.candidate).collect::<Vec<Symbol>>(),
1237 Some(found) if found != ident.name => {
1238 suggestions.into_iter().find(|suggestion| suggestion.candidate == found)
1244 fn lookup_import_candidates_from_module<FilterFn>(
1246 lookup_ident: Ident,
1247 namespace: Namespace,
1248 parent_scope: &ParentScope<'a>,
1249 start_module: Module<'a>,
1251 filter_fn: FilterFn,
1252 ) -> Vec<ImportSuggestion>
1254 FilterFn: Fn(Res) -> bool,
1256 let mut candidates = Vec::new();
1257 let mut seen_modules = FxHashSet::default();
1258 let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), true)];
1259 let mut worklist_via_import = vec![];
1261 while let Some((in_module, path_segments, accessible)) = match worklist.pop() {
1262 None => worklist_via_import.pop(),
1265 let in_module_is_extern = !in_module.def_id().is_local();
1266 // We have to visit module children in deterministic order to avoid
1267 // instabilities in reported imports (#43552).
1268 in_module.for_each_child(self, |this, ident, ns, name_binding| {
1269 // avoid non-importable candidates
1270 if !name_binding.is_importable() {
1274 let child_accessible =
1275 accessible && this.is_accessible_from(name_binding.vis, parent_scope.module);
1277 // do not venture inside inaccessible items of other crates
1278 if in_module_is_extern && !child_accessible {
1282 let via_import = name_binding.is_import() && !name_binding.is_extern_crate();
1284 // There is an assumption elsewhere that paths of variants are in the enum's
1285 // declaration and not imported. With this assumption, the variant component is
1286 // chopped and the rest of the path is assumed to be the enum's own path. For
1287 // errors where a variant is used as the type instead of the enum, this causes
1288 // funny looking invalid suggestions, i.e `foo` instead of `foo::MyEnum`.
1289 if via_import && name_binding.is_possibly_imported_variant() {
1293 // #90113: Do not count an inaccessible reexported item as a candidate.
1294 if let NameBindingKind::Import { binding, .. } = name_binding.kind {
1295 if this.is_accessible_from(binding.vis, parent_scope.module)
1296 && !this.is_accessible_from(name_binding.vis, parent_scope.module)
1302 // collect results based on the filter function
1303 // avoid suggesting anything from the same module in which we are resolving
1304 // avoid suggesting anything with a hygienic name
1305 if ident.name == lookup_ident.name
1307 && !ptr::eq(in_module, parent_scope.module)
1308 && !ident.span.normalize_to_macros_2_0().from_expansion()
1310 let res = name_binding.res();
1313 let mut segms = path_segments.clone();
1314 if lookup_ident.span.rust_2018() {
1315 // crate-local absolute paths start with `crate::` in edition 2018
1316 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
1317 segms.insert(0, ast::PathSegment::from_ident(crate_name));
1320 segms.push(ast::PathSegment::from_ident(ident));
1321 let path = Path { span: name_binding.span, segments: segms, tokens: None };
1322 let did = match res {
1323 Res::Def(DefKind::Ctor(..), did) => this.opt_parent(did),
1324 _ => res.opt_def_id(),
1327 if child_accessible {
1328 // Remove invisible match if exists
1329 if let Some(idx) = candidates
1331 .position(|v: &ImportSuggestion| v.did == did && !v.accessible)
1333 candidates.remove(idx);
1337 if candidates.iter().all(|v: &ImportSuggestion| v.did != did) {
1338 // See if we're recommending TryFrom, TryInto, or FromIterator and add
1339 // a note about editions
1340 let note = if let Some(did) = did {
1341 let requires_note = !did.is_local()
1342 && this.cstore().item_attrs_untracked(did, this.session).any(
1344 if attr.has_name(sym::rustc_diagnostic_item) {
1345 [sym::TryInto, sym::TryFrom, sym::FromIterator]
1347 .contains(&attr.value_str())
1354 requires_note.then(|| {
1356 "'{}' is included in the prelude starting in Edition 2021",
1357 path_names_to_string(&path)
1364 candidates.push(ImportSuggestion {
1368 accessible: child_accessible,
1375 // collect submodules to explore
1376 if let Some(module) = name_binding.module() {
1378 let mut path_segments = path_segments.clone();
1379 path_segments.push(ast::PathSegment::from_ident(ident));
1381 let is_extern_crate_that_also_appears_in_prelude =
1382 name_binding.is_extern_crate() && lookup_ident.span.rust_2018();
1384 if !is_extern_crate_that_also_appears_in_prelude {
1385 // add the module to the lookup
1386 if seen_modules.insert(module.def_id()) {
1387 if via_import { &mut worklist_via_import } else { &mut worklist }
1388 .push((module, path_segments, child_accessible));
1395 // If only some candidates are accessible, take just them
1396 if !candidates.iter().all(|v: &ImportSuggestion| !v.accessible) {
1397 candidates = candidates.into_iter().filter(|x| x.accessible).collect();
1403 /// When name resolution fails, this method can be used to look up candidate
1404 /// entities with the expected name. It allows filtering them using the
1405 /// supplied predicate (which should be used to only accept the types of
1406 /// definitions expected, e.g., traits). The lookup spans across all crates.
1408 /// N.B., the method does not look into imports, but this is not a problem,
1409 /// since we report the definitions (thus, the de-aliased imports).
1410 pub(crate) fn lookup_import_candidates<FilterFn>(
1412 lookup_ident: Ident,
1413 namespace: Namespace,
1414 parent_scope: &ParentScope<'a>,
1415 filter_fn: FilterFn,
1416 ) -> Vec<ImportSuggestion>
1418 FilterFn: Fn(Res) -> bool,
1420 let mut suggestions = self.lookup_import_candidates_from_module(
1425 Ident::with_dummy_span(kw::Crate),
1429 if lookup_ident.span.rust_2018() {
1430 let extern_prelude_names = self.extern_prelude.clone();
1431 for (ident, _) in extern_prelude_names.into_iter() {
1432 if ident.span.from_expansion() {
1433 // Idents are adjusted to the root context before being
1434 // resolved in the extern prelude, so reporting this to the
1435 // user is no help. This skips the injected
1436 // `extern crate std` in the 2018 edition, which would
1437 // otherwise cause duplicate suggestions.
1440 if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name) {
1441 let crate_root = self.expect_module(crate_id.as_def_id());
1442 suggestions.extend(self.lookup_import_candidates_from_module(
1457 pub(crate) fn unresolved_macro_suggestions(
1459 err: &mut Diagnostic,
1460 macro_kind: MacroKind,
1461 parent_scope: &ParentScope<'a>,
1464 let is_expected = &|res: Res| res.macro_kind() == Some(macro_kind);
1465 let suggestion = self.early_lookup_typo_candidate(
1466 ScopeSet::Macro(macro_kind),
1471 self.add_typo_suggestion(err, suggestion, ident.span);
1473 let import_suggestions =
1474 self.lookup_import_candidates(ident, Namespace::MacroNS, parent_scope, is_expected);
1480 &import_suggestions,
1487 if macro_kind == MacroKind::Derive && (ident.name == sym::Send || ident.name == sym::Sync) {
1488 let msg = format!("unsafe traits like `{}` should be implemented explicitly", ident);
1489 err.span_note(ident.span, &msg);
1492 if self.macro_names.contains(&ident.normalize_to_macros_2_0()) {
1493 err.help("have you added the `#[macro_use]` on the module/import?");
1496 if ident.name == kw::Default
1497 && let ModuleKind::Def(DefKind::Enum, def_id, _) = parent_scope.module.kind
1498 && let Some(span) = self.opt_span(def_id)
1500 let source_map = self.session.source_map();
1501 let head_span = source_map.guess_head_span(span);
1502 if let Ok(head) = source_map.span_to_snippet(head_span) {
1503 err.span_suggestion(head_span, "consider adding a derive", format!("#[derive(Default)]\n{head}"), Applicability::MaybeIncorrect);
1507 "consider adding `#[derive(Default)]` to this enum",
1511 for ns in [Namespace::MacroNS, Namespace::TypeNS, Namespace::ValueNS] {
1512 if let Ok(binding) = self.early_resolve_ident_in_lexical_scope(
1514 ScopeSet::All(ns, false),
1520 let desc = match binding.res() {
1521 Res::Def(DefKind::Macro(MacroKind::Bang), _) => {
1522 "a function-like macro".to_string()
1524 Res::Def(DefKind::Macro(MacroKind::Attr), _) | Res::NonMacroAttr(..) => {
1525 format!("an attribute: `#[{}]`", ident)
1527 Res::Def(DefKind::Macro(MacroKind::Derive), _) => {
1528 format!("a derive macro: `#[derive({})]`", ident)
1531 // Don't confuse the user with tool modules.
1534 Res::Def(DefKind::Trait, _) if macro_kind == MacroKind::Derive => {
1535 "only a trait, without a derive macro".to_string()
1541 macro_kind.article(),
1542 macro_kind.descr_expected(),
1545 if let crate::NameBindingKind::Import { import, .. } = binding.kind {
1546 if !import.span.is_dummy() {
1549 &format!("`{}` is imported here, but it is {}", ident, desc),
1551 // Silence the 'unused import' warning we might get,
1552 // since this diagnostic already covers that import.
1553 self.record_use(ident, binding, false);
1557 err.note(&format!("`{}` is in scope, but it is {}", ident, desc));
1563 pub(crate) fn add_typo_suggestion(
1565 err: &mut Diagnostic,
1566 suggestion: Option<TypoSuggestion>,
1569 let suggestion = match suggestion {
1570 None => return false,
1571 // We shouldn't suggest underscore.
1572 Some(suggestion) if suggestion.candidate == kw::Underscore => return false,
1573 Some(suggestion) => suggestion,
1575 let def_span = suggestion.res.opt_def_id().and_then(|def_id| match def_id.krate {
1576 LOCAL_CRATE => self.opt_span(def_id),
1577 _ => Some(self.cstore().get_span_untracked(def_id, self.session)),
1579 if let Some(def_span) = def_span {
1580 if span.overlaps(def_span) {
1581 // Don't suggest typo suggestion for itself like in the following:
1582 // error[E0423]: expected function, tuple struct or tuple variant, found struct `X`
1583 // --> $DIR/issue-64792-bad-unicode-ctor.rs:3:14
1586 // | ----------- `X` defined here
1588 // LL | const Y: X = X("ö");
1589 // | -------------^^^^^^- similarly named constant `Y` defined here
1591 // help: use struct literal syntax instead
1593 // LL | const Y: X = X {};
1595 // help: a constant with a similar name exists
1597 // LL | const Y: X = Y("ö");
1601 let prefix = match suggestion.target {
1602 SuggestionTarget::SimilarlyNamed => "similarly named ",
1603 SuggestionTarget::SingleItem => "",
1607 self.session.source_map().guess_head_span(def_span),
1609 "{}{} `{}` defined here",
1611 suggestion.res.descr(),
1612 suggestion.candidate,
1616 let msg = match suggestion.target {
1617 SuggestionTarget::SimilarlyNamed => format!(
1618 "{} {} with a similar name exists",
1619 suggestion.res.article(),
1620 suggestion.res.descr()
1622 SuggestionTarget::SingleItem => {
1623 format!("maybe you meant this {}", suggestion.res.descr())
1626 err.span_suggestion(span, &msg, suggestion.candidate, Applicability::MaybeIncorrect);
1630 fn binding_description(&self, b: &NameBinding<'_>, ident: Ident, from_prelude: bool) -> String {
1632 if b.span.is_dummy() || !self.session.source_map().is_span_accessible(b.span) {
1633 // These already contain the "built-in" prefix or look bad with it.
1635 !matches!(b.res(), Res::NonMacroAttr(..) | Res::PrimTy(..) | Res::ToolMod);
1636 let (built_in, from) = if from_prelude {
1637 ("", " from prelude")
1638 } else if b.is_extern_crate()
1640 && self.session.opts.externs.get(ident.as_str()).is_some()
1642 ("", " passed with `--extern`")
1643 } else if add_built_in {
1649 let a = if built_in.is_empty() { res.article() } else { "a" };
1650 format!("{a}{built_in} {thing}{from}", thing = res.descr())
1652 let introduced = if b.is_import() { "imported" } else { "defined" };
1653 format!("the {thing} {introduced} here", thing = res.descr())
1657 fn report_ambiguity_error(&self, ambiguity_error: &AmbiguityError<'_>) {
1658 let AmbiguityError { kind, ident, b1, b2, misc1, misc2 } = *ambiguity_error;
1659 let (b1, b2, misc1, misc2, swapped) = if b2.span.is_dummy() && !b1.span.is_dummy() {
1660 // We have to print the span-less alternative first, otherwise formatting looks bad.
1661 (b2, b1, misc2, misc1, true)
1663 (b1, b2, misc1, misc2, false)
1666 let mut err = struct_span_err!(self.session, ident.span, E0659, "`{ident}` is ambiguous");
1667 err.span_label(ident.span, "ambiguous name");
1668 err.note(&format!("ambiguous because of {}", kind.descr()));
1670 let mut could_refer_to = |b: &NameBinding<'_>, misc: AmbiguityErrorMisc, also: &str| {
1671 let what = self.binding_description(b, ident, misc == AmbiguityErrorMisc::FromPrelude);
1672 let note_msg = format!("`{ident}` could{also} refer to {what}");
1674 let thing = b.res().descr();
1675 let mut help_msgs = Vec::new();
1676 if b.is_glob_import()
1677 && (kind == AmbiguityKind::GlobVsGlob
1678 || kind == AmbiguityKind::GlobVsExpanded
1679 || kind == AmbiguityKind::GlobVsOuter && swapped != also.is_empty())
1681 help_msgs.push(format!(
1682 "consider adding an explicit import of `{ident}` to disambiguate"
1685 if b.is_extern_crate() && ident.span.rust_2018() {
1686 help_msgs.push(format!("use `::{ident}` to refer to this {thing} unambiguously"))
1688 if misc == AmbiguityErrorMisc::SuggestCrate {
1690 .push(format!("use `crate::{ident}` to refer to this {thing} unambiguously"))
1691 } else if misc == AmbiguityErrorMisc::SuggestSelf {
1693 .push(format!("use `self::{ident}` to refer to this {thing} unambiguously"))
1696 err.span_note(b.span, ¬e_msg);
1697 for (i, help_msg) in help_msgs.iter().enumerate() {
1698 let or = if i == 0 { "" } else { "or " };
1699 err.help(&format!("{}{}", or, help_msg));
1703 could_refer_to(b1, misc1, "");
1704 could_refer_to(b2, misc2, " also");
1708 /// If the binding refers to a tuple struct constructor with fields,
1709 /// returns the span of its fields.
1710 fn ctor_fields_span(&self, binding: &NameBinding<'_>) -> Option<Span> {
1711 if let NameBindingKind::Res(
1712 Res::Def(DefKind::Ctor(CtorOf::Struct, CtorKind::Fn), ctor_def_id),
1716 let def_id = self.parent(ctor_def_id);
1717 let fields = self.field_names.get(&def_id)?;
1718 return fields.iter().map(|name| name.span).reduce(Span::to); // None for `struct Foo()`
1723 fn report_privacy_error(&self, privacy_error: &PrivacyError<'_>) {
1724 let PrivacyError { ident, binding, .. } = *privacy_error;
1726 let res = binding.res();
1727 let ctor_fields_span = self.ctor_fields_span(binding);
1728 let plain_descr = res.descr().to_string();
1729 let nonimport_descr =
1730 if ctor_fields_span.is_some() { plain_descr + " constructor" } else { plain_descr };
1731 let import_descr = nonimport_descr.clone() + " import";
1733 |b: &NameBinding<'_>| if b.is_import() { &import_descr } else { &nonimport_descr };
1735 // Print the primary message.
1736 let descr = get_descr(binding);
1738 struct_span_err!(self.session, ident.span, E0603, "{} `{}` is private", descr, ident);
1739 err.span_label(ident.span, &format!("private {}", descr));
1740 if let Some(span) = ctor_fields_span {
1741 err.span_label(span, "a constructor is private if any of the fields is private");
1744 // Print the whole import chain to make it easier to see what happens.
1745 let first_binding = binding;
1746 let mut next_binding = Some(binding);
1747 let mut next_ident = ident;
1748 while let Some(binding) = next_binding {
1749 let name = next_ident;
1750 next_binding = match binding.kind {
1751 _ if res == Res::Err => None,
1752 NameBindingKind::Import { binding, import, .. } => match import.kind {
1753 _ if binding.span.is_dummy() => None,
1754 ImportKind::Single { source, .. } => {
1755 next_ident = source;
1758 ImportKind::Glob { .. } | ImportKind::MacroUse => Some(binding),
1759 ImportKind::ExternCrate { .. } => None,
1764 let first = ptr::eq(binding, first_binding);
1766 "{and_refers_to}the {item} `{name}`{which} is defined here{dots}",
1767 and_refers_to = if first { "" } else { "...and refers to " },
1768 item = get_descr(binding),
1769 which = if first { "" } else { " which" },
1770 dots = if next_binding.is_some() { "..." } else { "" },
1772 let def_span = self.session.source_map().guess_head_span(binding.span);
1773 let mut note_span = MultiSpan::from_span(def_span);
1774 if !first && binding.vis.is_public() {
1775 note_span.push_span_label(def_span, "consider importing it directly");
1777 err.span_note(note_span, &msg);
1783 pub(crate) fn find_similarly_named_module_or_crate(
1786 current_module: &Module<'a>,
1787 ) -> Option<Symbol> {
1788 let mut candidates = self
1791 .map(|(ident, _)| ident.name)
1795 .filter(|(_, module)| {
1796 current_module.is_ancestor_of(module) && !ptr::eq(current_module, *module)
1798 .flat_map(|(_, module)| module.kind.name()),
1800 .filter(|c| !c.to_string().is_empty())
1801 .collect::<Vec<_>>();
1804 match find_best_match_for_name(&candidates, ident, None) {
1805 Some(sugg) if sugg == ident => None,
1810 pub(crate) fn report_path_resolution_error(
1813 opt_ns: Option<Namespace>, // `None` indicates a module path in import
1814 parent_scope: &ParentScope<'a>,
1815 ribs: Option<&PerNS<Vec<Rib<'a>>>>,
1816 ignore_binding: Option<&'a NameBinding<'a>>,
1817 module: Option<ModuleOrUniformRoot<'a>>,
1820 ) -> (String, Option<Suggestion>) {
1821 let is_last = i == path.len() - 1;
1822 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
1823 let module_res = match module {
1824 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
1827 if module_res == self.graph_root.res() {
1828 let is_mod = |res| matches!(res, Res::Def(DefKind::Mod, _));
1829 let mut candidates = self.lookup_import_candidates(ident, TypeNS, parent_scope, is_mod);
1831 .sort_by_cached_key(|c| (c.path.segments.len(), pprust::path_to_string(&c.path)));
1832 if let Some(candidate) = candidates.get(0) {
1834 String::from("unresolved import"),
1836 vec![(ident.span, pprust::path_to_string(&candidate.path))],
1837 String::from("a similar path exists"),
1838 Applicability::MaybeIncorrect,
1841 } else if self.session.edition() == Edition::Edition2015 {
1843 format!("maybe a missing crate `{ident}`?"),
1847 "consider adding `extern crate {ident}` to use the `{ident}` crate"
1849 Applicability::MaybeIncorrect,
1853 (format!("could not find `{ident}` in the crate root"), None)
1856 let parent = path[i - 1].ident.name;
1857 let parent = match parent {
1858 // ::foo is mounted at the crate root for 2015, and is the extern
1859 // prelude for 2018+
1860 kw::PathRoot if self.session.edition() > Edition::Edition2015 => {
1861 "the list of imported crates".to_owned()
1863 kw::PathRoot | kw::Crate => "the crate root".to_owned(),
1864 _ => format!("`{parent}`"),
1867 let mut msg = format!("could not find `{}` in {}", ident, parent);
1868 if ns == TypeNS || ns == ValueNS {
1869 let ns_to_try = if ns == TypeNS { ValueNS } else { TypeNS };
1870 let binding = if let Some(module) = module {
1871 self.resolve_ident_in_module(
1879 } else if let Some(ribs) = ribs
1880 && let Some(TypeNS | ValueNS) = opt_ns
1882 match self.resolve_ident_in_lexical_scope(
1890 // we found a locally-imported or available item/module
1891 Some(LexicalScopeBinding::Item(binding)) => Some(binding),
1895 let scopes = ScopeSet::All(ns_to_try, opt_ns.is_none());
1896 self.early_resolve_ident_in_lexical_scope(
1905 if let Some(binding) = binding {
1906 let mut found = |what| {
1908 "expected {}, found {} `{}` in {}",
1915 if binding.module().is_some() {
1918 match binding.res() {
1919 Res::Def(kind, id) => found(kind.descr(id)),
1920 _ => found(ns_to_try.descr()),
1926 } else if ident.name == kw::SelfUpper {
1927 ("`Self` is only available in impls, traits, and type definitions".to_string(), None)
1928 } else if ident.name.as_str().chars().next().map_or(false, |c| c.is_ascii_uppercase()) {
1929 // Check whether the name refers to an item in the value namespace.
1930 let binding = if let Some(ribs) = ribs {
1931 self.resolve_ident_in_lexical_scope(
1942 let match_span = match binding {
1943 // Name matches a local variable. For example:
1946 // let Foo: &str = "";
1947 // println!("{}", Foo::Bar); // Name refers to local
1948 // // variable `Foo`.
1951 Some(LexicalScopeBinding::Res(Res::Local(id))) => {
1952 Some(*self.pat_span_map.get(&id).unwrap())
1954 // Name matches item from a local name binding
1955 // created by `use` declaration. For example:
1957 // pub Foo: &str = "";
1961 // println!("{}", Foo::Bar); // Name refers to local
1962 // // binding `Foo`.
1965 Some(LexicalScopeBinding::Item(name_binding)) => Some(name_binding.span),
1968 let suggestion = if let Some(span) = match_span {
1970 vec![(span, String::from(""))],
1971 format!("`{}` is defined here, but is not a type", ident),
1972 Applicability::MaybeIncorrect,
1978 (format!("use of undeclared type `{}`", ident), suggestion)
1980 let suggestion = if ident.name == sym::alloc {
1983 String::from("add `extern crate alloc` to use the `alloc` crate"),
1984 Applicability::MaybeIncorrect,
1987 self.find_similarly_named_module_or_crate(ident.name, &parent_scope.module).map(
1990 vec![(ident.span, sugg.to_string())],
1991 String::from("there is a crate or module with a similar name"),
1992 Applicability::MaybeIncorrect,
1997 (format!("use of undeclared crate or module `{}`", ident), suggestion)
2002 impl<'a, 'b> ImportResolver<'a, 'b> {
2003 /// Adds suggestions for a path that cannot be resolved.
2004 pub(crate) fn make_path_suggestion(
2007 mut path: Vec<Segment>,
2008 parent_scope: &ParentScope<'b>,
2009 ) -> Option<(Vec<Segment>, Option<String>)> {
2010 debug!("make_path_suggestion: span={:?} path={:?}", span, path);
2012 match (path.get(0), path.get(1)) {
2013 // `{{root}}::ident::...` on both editions.
2014 // On 2015 `{{root}}` is usually added implicitly.
2015 (Some(fst), Some(snd))
2016 if fst.ident.name == kw::PathRoot && !snd.ident.is_path_segment_keyword() => {}
2017 // `ident::...` on 2018.
2019 if fst.ident.span.rust_2018() && !fst.ident.is_path_segment_keyword() =>
2021 // Insert a placeholder that's later replaced by `self`/`super`/etc.
2022 path.insert(0, Segment::from_ident(Ident::empty()));
2027 self.make_missing_self_suggestion(path.clone(), parent_scope)
2028 .or_else(|| self.make_missing_crate_suggestion(path.clone(), parent_scope))
2029 .or_else(|| self.make_missing_super_suggestion(path.clone(), parent_scope))
2030 .or_else(|| self.make_external_crate_suggestion(path, parent_scope))
2033 /// Suggest a missing `self::` if that resolves to an correct module.
2037 /// LL | use foo::Bar;
2038 /// | ^^^ did you mean `self::foo`?
2040 fn make_missing_self_suggestion(
2042 mut path: Vec<Segment>,
2043 parent_scope: &ParentScope<'b>,
2044 ) -> Option<(Vec<Segment>, Option<String>)> {
2045 // Replace first ident with `self` and check if that is valid.
2046 path[0].ident.name = kw::SelfLower;
2047 let result = self.r.maybe_resolve_path(&path, None, parent_scope);
2048 debug!("make_missing_self_suggestion: path={:?} result={:?}", path, result);
2049 if let PathResult::Module(..) = result { Some((path, None)) } else { None }
2052 /// Suggests a missing `crate::` if that resolves to an correct module.
2056 /// LL | use foo::Bar;
2057 /// | ^^^ did you mean `crate::foo`?
2059 fn make_missing_crate_suggestion(
2061 mut path: Vec<Segment>,
2062 parent_scope: &ParentScope<'b>,
2063 ) -> Option<(Vec<Segment>, Option<String>)> {
2064 // Replace first ident with `crate` and check if that is valid.
2065 path[0].ident.name = kw::Crate;
2066 let result = self.r.maybe_resolve_path(&path, None, parent_scope);
2067 debug!("make_missing_crate_suggestion: path={:?} result={:?}", path, result);
2068 if let PathResult::Module(..) = result {
2072 "`use` statements changed in Rust 2018; read more at \
2073 <https://doc.rust-lang.org/edition-guide/rust-2018/module-system/path-\
2083 /// Suggests a missing `super::` if that resolves to an correct module.
2087 /// LL | use foo::Bar;
2088 /// | ^^^ did you mean `super::foo`?
2090 fn make_missing_super_suggestion(
2092 mut path: Vec<Segment>,
2093 parent_scope: &ParentScope<'b>,
2094 ) -> Option<(Vec<Segment>, Option<String>)> {
2095 // Replace first ident with `crate` and check if that is valid.
2096 path[0].ident.name = kw::Super;
2097 let result = self.r.maybe_resolve_path(&path, None, parent_scope);
2098 debug!("make_missing_super_suggestion: path={:?} result={:?}", path, result);
2099 if let PathResult::Module(..) = result { Some((path, None)) } else { None }
2102 /// Suggests a missing external crate name if that resolves to an correct module.
2106 /// LL | use foobar::Baz;
2107 /// | ^^^^^^ did you mean `baz::foobar`?
2110 /// Used when importing a submodule of an external crate but missing that crate's
2111 /// name as the first part of path.
2112 fn make_external_crate_suggestion(
2114 mut path: Vec<Segment>,
2115 parent_scope: &ParentScope<'b>,
2116 ) -> Option<(Vec<Segment>, Option<String>)> {
2117 if path[1].ident.span.rust_2015() {
2121 // Sort extern crate names in *reverse* order to get
2122 // 1) some consistent ordering for emitted diagnostics, and
2123 // 2) `std` suggestions before `core` suggestions.
2124 let mut extern_crate_names =
2125 self.r.extern_prelude.iter().map(|(ident, _)| ident.name).collect::<Vec<_>>();
2126 extern_crate_names.sort_by(|a, b| b.as_str().partial_cmp(a.as_str()).unwrap());
2128 for name in extern_crate_names.into_iter() {
2129 // Replace first ident with a crate name and check if that is valid.
2130 path[0].ident.name = name;
2131 let result = self.r.maybe_resolve_path(&path, None, parent_scope);
2133 "make_external_crate_suggestion: name={:?} path={:?} result={:?}",
2136 if let PathResult::Module(..) = result {
2137 return Some((path, None));
2144 /// Suggests importing a macro from the root of the crate rather than a module within
2148 /// help: a macro with this name exists at the root of the crate
2150 /// LL | use issue_59764::makro;
2151 /// | ^^^^^^^^^^^^^^^^^^
2153 /// = note: this could be because a macro annotated with `#[macro_export]` will be exported
2154 /// at the root of the crate instead of the module where it is defined
2156 pub(crate) fn check_for_module_export_macro(
2158 import: &'b Import<'b>,
2159 module: ModuleOrUniformRoot<'b>,
2161 ) -> Option<(Option<Suggestion>, Option<String>)> {
2162 let ModuleOrUniformRoot::Module(mut crate_module) = module else {
2166 while let Some(parent) = crate_module.parent {
2167 crate_module = parent;
2170 if ModuleOrUniformRoot::same_def(ModuleOrUniformRoot::Module(crate_module), module) {
2171 // Don't make a suggestion if the import was already from the root of the
2176 let resolutions = self.r.resolutions(crate_module).borrow();
2177 let resolution = resolutions.get(&self.r.new_key(ident, MacroNS))?;
2178 let binding = resolution.borrow().binding()?;
2179 if let Res::Def(DefKind::Macro(MacroKind::Bang), _) = binding.res() {
2180 let module_name = crate_module.kind.name().unwrap();
2181 let import_snippet = match import.kind {
2182 ImportKind::Single { source, target, .. } if source != target => {
2183 format!("{} as {}", source, target)
2185 _ => format!("{}", ident),
2188 let mut corrections: Vec<(Span, String)> = Vec::new();
2189 if !import.is_nested() {
2190 // Assume this is the easy case of `use issue_59764::foo::makro;` and just remove
2191 // intermediate segments.
2192 corrections.push((import.span, format!("{}::{}", module_name, import_snippet)));
2194 // Find the binding span (and any trailing commas and spaces).
2195 // ie. `use a::b::{c, d, e};`
2197 let (found_closing_brace, binding_span) = find_span_of_binding_until_next_binding(
2203 "check_for_module_export_macro: found_closing_brace={:?} binding_span={:?}",
2204 found_closing_brace, binding_span
2207 let mut removal_span = binding_span;
2208 if found_closing_brace {
2209 // If the binding span ended with a closing brace, as in the below example:
2210 // ie. `use a::b::{c, d};`
2212 // Then expand the span of characters to remove to include the previous
2213 // binding's trailing comma.
2214 // ie. `use a::b::{c, d};`
2216 if let Some(previous_span) =
2217 extend_span_to_previous_binding(self.r.session, binding_span)
2219 debug!("check_for_module_export_macro: previous_span={:?}", previous_span);
2220 removal_span = removal_span.with_lo(previous_span.lo());
2223 debug!("check_for_module_export_macro: removal_span={:?}", removal_span);
2225 // Remove the `removal_span`.
2226 corrections.push((removal_span, "".to_string()));
2228 // Find the span after the crate name and if it has nested imports immediately
2229 // after the crate name already.
2230 // ie. `use a::b::{c, d};`
2232 // or `use a::{b, c, d}};`
2234 let (has_nested, after_crate_name) = find_span_immediately_after_crate_name(
2240 "check_for_module_export_macro: has_nested={:?} after_crate_name={:?}",
2241 has_nested, after_crate_name
2244 let source_map = self.r.session.source_map();
2246 // Add the import to the start, with a `{` if required.
2247 let start_point = source_map.start_point(after_crate_name);
2248 if let Ok(start_snippet) = source_map.span_to_snippet(start_point) {
2252 // In this case, `start_snippet` must equal '{'.
2253 format!("{}{}, ", start_snippet, import_snippet)
2255 // In this case, add a `{`, then the moved import, then whatever
2256 // was there before.
2257 format!("{{{}, {}", import_snippet, start_snippet)
2262 // Add a `};` to the end if nested, matching the `{` added at the start.
2264 corrections.push((source_map.end_point(after_crate_name), "};".to_string()));
2268 let suggestion = Some((
2270 String::from("a macro with this name exists at the root of the crate"),
2271 Applicability::MaybeIncorrect,
2273 Some((suggestion, Some("this could be because a macro annotated with `#[macro_export]` will be exported \
2274 at the root of the crate instead of the module where it is defined"
2282 /// Given a `binding_span` of a binding within a use statement:
2284 /// ```ignore (illustrative)
2285 /// use foo::{a, b, c};
2289 /// then return the span until the next binding or the end of the statement:
2291 /// ```ignore (illustrative)
2292 /// use foo::{a, b, c};
2295 fn find_span_of_binding_until_next_binding(
2300 let source_map = sess.source_map();
2302 // Find the span of everything after the binding.
2303 // ie. `a, e};` or `a};`
2304 let binding_until_end = binding_span.with_hi(use_span.hi());
2306 // Find everything after the binding but not including the binding.
2307 // ie. `, e};` or `};`
2308 let after_binding_until_end = binding_until_end.with_lo(binding_span.hi());
2310 // Keep characters in the span until we encounter something that isn't a comma or
2314 // Also note whether a closing brace character was encountered. If there
2315 // was, then later go backwards to remove any trailing commas that are left.
2316 let mut found_closing_brace = false;
2317 let after_binding_until_next_binding =
2318 source_map.span_take_while(after_binding_until_end, |&ch| {
2320 found_closing_brace = true;
2322 ch == ' ' || ch == ','
2325 // Combine the two spans.
2326 // ie. `a, ` or `a`.
2328 // Removing these would leave `issue_52891::{d, e};` or `issue_52891::{d, e, };`
2329 let span = binding_span.with_hi(after_binding_until_next_binding.hi());
2331 (found_closing_brace, span)
2334 /// Given a `binding_span`, return the span through to the comma or opening brace of the previous
2337 /// ```ignore (illustrative)
2338 /// use foo::a::{a, b, c};
2339 /// // ^^--- binding span
2341 /// // returned span
2343 /// use foo::{a, b, c};
2344 /// // --- binding span
2346 fn extend_span_to_previous_binding(sess: &Session, binding_span: Span) -> Option<Span> {
2347 let source_map = sess.source_map();
2349 // `prev_source` will contain all of the source that came before the span.
2350 // Then split based on a command and take the first (ie. closest to our span)
2351 // snippet. In the example, this is a space.
2352 let prev_source = source_map.span_to_prev_source(binding_span).ok()?;
2354 let prev_comma = prev_source.rsplit(',').collect::<Vec<_>>();
2355 let prev_starting_brace = prev_source.rsplit('{').collect::<Vec<_>>();
2356 if prev_comma.len() <= 1 || prev_starting_brace.len() <= 1 {
2360 let prev_comma = prev_comma.first().unwrap();
2361 let prev_starting_brace = prev_starting_brace.first().unwrap();
2363 // If the amount of source code before the comma is greater than
2364 // the amount of source code before the starting brace then we've only
2365 // got one item in the nested item (eg. `issue_52891::{self}`).
2366 if prev_comma.len() > prev_starting_brace.len() {
2370 Some(binding_span.with_lo(BytePos(
2371 // Take away the number of bytes for the characters we've found and an
2372 // extra for the comma.
2373 binding_span.lo().0 - (prev_comma.as_bytes().len() as u32) - 1,
2377 /// Given a `use_span` of a binding within a use statement, returns the highlighted span and if
2378 /// it is a nested use tree.
2380 /// ```ignore (illustrative)
2381 /// use foo::a::{b, c};
2382 /// // ^^^^^^^^^^ -- false
2384 /// use foo::{a, b, c};
2385 /// // ^^^^^^^^^^ -- true
2387 /// use foo::{a, b::{c, d}};
2388 /// // ^^^^^^^^^^^^^^^ -- true
2390 fn find_span_immediately_after_crate_name(
2392 module_name: Symbol,
2396 "find_span_immediately_after_crate_name: module_name={:?} use_span={:?}",
2397 module_name, use_span
2399 let source_map = sess.source_map();
2401 // Using `use issue_59764::foo::{baz, makro};` as an example throughout..
2402 let mut num_colons = 0;
2403 // Find second colon.. `use issue_59764:`
2404 let until_second_colon = source_map.span_take_while(use_span, |c| {
2408 !matches!(c, ':' if num_colons == 2)
2410 // Find everything after the second colon.. `foo::{baz, makro};`
2411 let from_second_colon = use_span.with_lo(until_second_colon.hi() + BytePos(1));
2413 let mut found_a_non_whitespace_character = false;
2414 // Find the first non-whitespace character in `from_second_colon`.. `f`
2415 let after_second_colon = source_map.span_take_while(from_second_colon, |c| {
2416 if found_a_non_whitespace_character {
2419 if !c.is_whitespace() {
2420 found_a_non_whitespace_character = true;
2425 // Find the first `{` in from_second_colon.. `foo::{`
2426 let next_left_bracket = source_map.span_through_char(from_second_colon, '{');
2428 (next_left_bracket == after_second_colon, from_second_colon)
2431 /// A suggestion has already been emitted, change the wording slightly to clarify that both are
2432 /// independent options.
2438 /// Whether an existing place with an `use` item was found.
2444 /// Whether a binding is part of a pattern or an expression. Used for diagnostics.
2446 /// The binding is part of a pattern
2448 /// The binding is part of an expression
2452 /// When an entity with a given name is not available in scope, we search for
2453 /// entities with that name in all crates. This method allows outputting the
2454 /// results of this search in a programmer-friendly way
2457 source_span: &IndexVec<LocalDefId, Span>,
2458 err: &mut Diagnostic,
2459 // This is `None` if all placement locations are inside expansions
2460 use_placement_span: Option<Span>,
2461 candidates: &[ImportSuggestion],
2463 found_use: FoundUse,
2464 is_pattern: IsPattern,
2467 if candidates.is_empty() {
2471 let mut accessible_path_strings: Vec<(String, &str, Option<DefId>, &Option<String>)> =
2473 let mut inaccessible_path_strings: Vec<(String, &str, Option<DefId>, &Option<String>)> =
2476 candidates.iter().for_each(|c| {
2477 (if c.accessible { &mut accessible_path_strings } else { &mut inaccessible_path_strings })
2478 .push((path_names_to_string(&c.path), c.descr, c.did, &c.note))
2481 // we want consistent results across executions, but candidates are produced
2482 // by iterating through a hash map, so make sure they are ordered:
2483 for path_strings in [&mut accessible_path_strings, &mut inaccessible_path_strings] {
2484 path_strings.sort_by(|a, b| a.0.cmp(&b.0));
2485 let core_path_strings =
2486 path_strings.drain_filter(|p| p.0.starts_with("core::")).collect::<Vec<_>>();
2487 path_strings.extend(core_path_strings);
2488 path_strings.dedup_by(|a, b| a.0 == b.0);
2491 if !accessible_path_strings.is_empty() {
2492 let (determiner, kind, name) = if accessible_path_strings.len() == 1 {
2493 ("this", accessible_path_strings[0].1, format!(" `{}`", accessible_path_strings[0].0))
2495 ("one of these", "items", String::new())
2498 let instead = if let Instead::Yes = instead { " instead" } else { "" };
2499 let mut msg = if let IsPattern::Yes = is_pattern {
2501 "if you meant to match on {}{}{}, use the full path in the pattern",
2505 format!("consider importing {} {}{}", determiner, kind, instead)
2508 for note in accessible_path_strings.iter().flat_map(|cand| cand.3.as_ref()) {
2512 if let (IsPattern::Yes, Some(span)) = (is_pattern, use_placement_span) {
2513 err.span_suggestions(
2516 accessible_path_strings.into_iter().map(|a| a.0),
2517 Applicability::MaybeIncorrect,
2519 } else if let Some(span) = use_placement_span {
2520 for candidate in &mut accessible_path_strings {
2521 // produce an additional newline to separate the new use statement
2522 // from the directly following item.
2523 let additional_newline = if let FoundUse::Yes = found_use { "" } else { "\n" };
2524 candidate.0 = format!("use {};\n{}", &candidate.0, additional_newline);
2527 err.span_suggestions(
2530 accessible_path_strings.into_iter().map(|a| a.0),
2531 Applicability::MaybeIncorrect,
2533 if let [first, .., last] = &path[..] {
2534 let sp = first.ident.span.until(last.ident.span);
2535 if sp.can_be_used_for_suggestions() {
2536 err.span_suggestion_verbose(
2538 &format!("if you import `{}`, refer to it directly", last.ident),
2540 Applicability::Unspecified,
2547 for candidate in accessible_path_strings {
2549 msg.push_str(&candidate.0);
2555 assert!(!inaccessible_path_strings.is_empty());
2558 if let IsPattern::Yes = is_pattern { "you might have meant to match on " } else { "" };
2559 if inaccessible_path_strings.len() == 1 {
2560 let (name, descr, def_id, note) = &inaccessible_path_strings[0];
2562 "{}{} `{}`{} exists but is inaccessible",
2566 if let IsPattern::Yes = is_pattern { ", which" } else { "" }
2569 if let Some(local_def_id) = def_id.and_then(|did| did.as_local()) {
2570 let span = source_span[local_def_id];
2571 let span = session.source_map().guess_head_span(span);
2572 let mut multi_span = MultiSpan::from_span(span);
2573 multi_span.push_span_label(span, "not accessible");
2574 err.span_note(multi_span, &msg);
2578 if let Some(note) = (*note).as_deref() {
2582 let (_, descr_first, _, _) = &inaccessible_path_strings[0];
2583 let descr = if inaccessible_path_strings
2586 .all(|(_, descr, _, _)| descr == descr_first)
2593 if descr.ends_with('s') { format!("{}es", descr) } else { format!("{}s", descr) };
2595 let mut msg = format!("{}these {} exist but are inaccessible", prefix, plural_descr);
2596 let mut has_colon = false;
2598 let mut spans = Vec::new();
2599 for (name, _, def_id, _) in &inaccessible_path_strings {
2600 if let Some(local_def_id) = def_id.and_then(|did| did.as_local()) {
2601 let span = source_span[local_def_id];
2602 let span = session.source_map().guess_head_span(span);
2603 spans.push((name, span));
2614 let mut multi_span = MultiSpan::from_spans(spans.iter().map(|(_, sp)| *sp).collect());
2615 for (name, span) in spans {
2616 multi_span.push_span_label(span, format!("`{}`: not accessible", name));
2619 for note in inaccessible_path_strings.iter().flat_map(|cand| cand.3.as_ref()) {
2623 err.span_note(multi_span, &msg);
2629 struct UsePlacementFinder {
2630 target_module: NodeId,
2631 first_legal_span: Option<Span>,
2632 first_use_span: Option<Span>,
2635 impl UsePlacementFinder {
2636 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, FoundUse) {
2638 UsePlacementFinder { target_module, first_legal_span: None, first_use_span: None };
2639 finder.visit_crate(krate);
2640 if let Some(use_span) = finder.first_use_span {
2641 (Some(use_span), FoundUse::Yes)
2643 (finder.first_legal_span, FoundUse::No)
2648 impl<'tcx> visit::Visitor<'tcx> for UsePlacementFinder {
2649 fn visit_crate(&mut self, c: &Crate) {
2650 if self.target_module == CRATE_NODE_ID {
2651 let inject = c.spans.inject_use_span;
2652 if is_span_suitable_for_use_injection(inject) {
2653 self.first_legal_span = Some(inject);
2655 self.first_use_span = search_for_any_use_in_items(&c.items);
2658 visit::walk_crate(self, c);
2662 fn visit_item(&mut self, item: &'tcx ast::Item) {
2663 if self.target_module == item.id {
2664 if let ItemKind::Mod(_, ModKind::Loaded(items, _inline, mod_spans)) = &item.kind {
2665 let inject = mod_spans.inject_use_span;
2666 if is_span_suitable_for_use_injection(inject) {
2667 self.first_legal_span = Some(inject);
2669 self.first_use_span = search_for_any_use_in_items(items);
2673 visit::walk_item(self, item);
2678 fn search_for_any_use_in_items(items: &[P<ast::Item>]) -> Option<Span> {
2680 if let ItemKind::Use(..) = item.kind {
2681 if is_span_suitable_for_use_injection(item.span) {
2682 return Some(item.span.shrink_to_lo());
2689 fn is_span_suitable_for_use_injection(s: Span) -> bool {
2690 // don't suggest placing a use before the prelude
2691 // import or other generated ones
2695 /// Convert the given number into the corresponding ordinal
2696 pub(crate) fn ordinalize(v: usize) -> String {
2697 let suffix = match ((11..=13).contains(&(v % 100)), v % 10) {
2703 format!("{v}{suffix}")