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, SyntaxContext};
29 use crate::imports::{Import, ImportKind, ImportResolver};
30 use crate::late::{PatternSource, Rib};
31 use crate::path_names_to_string;
32 use crate::{AmbiguityError, AmbiguityErrorMisc, AmbiguityKind, BindingError, Finalize};
33 use crate::{HasGenericParams, MacroRulesScope, Module, ModuleKind, ModuleOrUniformRoot};
34 use crate::{LexicalScopeBinding, NameBinding, NameBindingKind, PrivacyError, VisResolutionError};
35 use crate::{ParentScope, PathResult, ResolutionError, Resolver, Scope, ScopeSet};
36 use crate::{Segment, UseError};
41 type Res = def::Res<ast::NodeId>;
43 /// A vector of spans and replacements, a message and applicability.
44 pub(crate) type Suggestion = (Vec<(Span, String)>, String, Applicability);
46 /// Potential candidate for an undeclared or out-of-scope label - contains the ident of a
47 /// similarly named label and whether or not it is reachable.
48 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
59 pub(crate) struct TypoSuggestion {
60 pub candidate: Symbol,
61 /// The source location where the name is defined; None if the name is not defined
62 /// in source e.g. primitives
63 pub span: Option<Span>,
65 pub target: SuggestionTarget,
69 pub(crate) fn typo_from_ident(ident: Ident, res: Res) -> TypoSuggestion {
71 candidate: ident.name,
72 span: Some(ident.span),
74 target: SuggestionTarget::SimilarlyNamed,
77 pub(crate) fn typo_from_name(candidate: Symbol, res: Res) -> TypoSuggestion {
78 Self { candidate, span: None, res, target: SuggestionTarget::SimilarlyNamed }
80 pub(crate) fn single_item_from_ident(ident: Ident, res: Res) -> TypoSuggestion {
82 candidate: ident.name,
83 span: Some(ident.span),
85 target: SuggestionTarget::SingleItem,
90 /// A free importable items suggested in case of resolution failure.
91 #[derive(Debug, Clone)]
92 pub(crate) struct ImportSuggestion {
93 pub did: Option<DefId>,
94 pub descr: &'static str,
97 /// An extra note that should be issued if this item is suggested
98 pub note: Option<String>,
101 /// Adjust the impl span so that just the `impl` keyword is taken by removing
102 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
103 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`).
105 /// *Attention*: the method used is very fragile since it essentially duplicates the work of the
106 /// parser. If you need to use this function or something similar, please consider updating the
107 /// `source_map` functions and this function to something more robust.
108 fn reduce_impl_span_to_impl_keyword(sm: &SourceMap, impl_span: Span) -> Span {
109 let impl_span = sm.span_until_char(impl_span, '<');
110 sm.span_until_whitespace(impl_span)
113 impl<'a> Resolver<'a> {
114 pub(crate) fn report_errors(&mut self, krate: &Crate) {
115 self.report_with_use_injections(krate);
117 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
118 let msg = "macro-expanded `macro_export` macros from the current crate \
119 cannot be referred to by absolute paths";
120 self.lint_buffer.buffer_lint_with_diagnostic(
121 MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
125 BuiltinLintDiagnostics::MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
129 for ambiguity_error in &self.ambiguity_errors {
130 self.report_ambiguity_error(ambiguity_error);
133 let mut reported_spans = FxHashSet::default();
134 for error in &self.privacy_errors {
135 if reported_spans.insert(error.dedup_span) {
136 self.report_privacy_error(error);
141 fn report_with_use_injections(&mut self, krate: &Crate) {
142 for UseError { mut err, candidates, def_id, instead, suggestion, path, is_call } in
143 self.use_injections.drain(..)
145 let (span, found_use) = if let Some(def_id) = def_id.as_local() {
146 UsePlacementFinder::check(krate, self.def_id_to_node_id[def_id])
151 if !candidates.is_empty() {
158 if instead { Instead::Yes } else { Instead::No },
160 DiagnosticMode::Normal,
164 } else if let Some((span, msg, sugg, appl)) = suggestion {
165 err.span_suggestion(span, msg, sugg, appl);
167 } else if let [segment] = path.as_slice() && is_call {
168 err.stash(segment.ident.span, rustc_errors::StashKey::CallIntoMethod);
175 pub(crate) fn report_conflict<'b>(
180 new_binding: &NameBinding<'b>,
181 old_binding: &NameBinding<'b>,
183 // Error on the second of two conflicting names
184 if old_binding.span.lo() > new_binding.span.lo() {
185 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
188 let container = match parent.kind {
189 ModuleKind::Def(kind, _, _) => kind.descr(parent.def_id()),
190 ModuleKind::Block => "block",
193 let old_noun = match old_binding.is_import() {
195 false => "definition",
198 let new_participle = match new_binding.is_import() {
204 (ident.name, self.session.source_map().guess_head_span(new_binding.span));
206 if let Some(s) = self.name_already_seen.get(&name) {
212 let old_kind = match (ns, old_binding.module()) {
213 (ValueNS, _) => "value",
214 (MacroNS, _) => "macro",
215 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
216 (TypeNS, Some(module)) if module.is_normal() => "module",
217 (TypeNS, Some(module)) if module.is_trait() => "trait",
218 (TypeNS, _) => "type",
221 let msg = format!("the name `{}` is defined multiple times", name);
223 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
224 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
225 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
226 true => struct_span_err!(self.session, span, E0254, "{}", msg),
227 false => struct_span_err!(self.session, span, E0260, "{}", msg),
229 _ => match (old_binding.is_import(), new_binding.is_import()) {
230 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
231 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
232 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
237 "`{}` must be defined only once in the {} namespace of this {}",
243 err.span_label(span, format!("`{}` re{} here", name, new_participle));
245 self.session.source_map().guess_head_span(old_binding.span),
246 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
249 // See https://github.com/rust-lang/rust/issues/32354
250 use NameBindingKind::Import;
251 let import = match (&new_binding.kind, &old_binding.kind) {
252 // If there are two imports where one or both have attributes then prefer removing the
253 // import without attributes.
254 (Import { import: new, .. }, Import { import: old, .. })
256 !new_binding.span.is_dummy()
257 && !old_binding.span.is_dummy()
258 && (new.has_attributes || old.has_attributes)
261 if old.has_attributes {
262 Some((new, new_binding.span, true))
264 Some((old, old_binding.span, true))
267 // Otherwise prioritize the new binding.
268 (Import { import, .. }, other) if !new_binding.span.is_dummy() => {
269 Some((import, new_binding.span, other.is_import()))
271 (other, Import { import, .. }) if !old_binding.span.is_dummy() => {
272 Some((import, old_binding.span, other.is_import()))
277 // Check if the target of the use for both bindings is the same.
278 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
279 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
281 self.extern_prelude.get(&ident).map_or(true, |entry| entry.introduced_by_item);
282 // Only suggest removing an import if both bindings are to the same def, if both spans
283 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
284 // been introduced by an item.
285 let should_remove_import = duplicate
287 && ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
290 Some((import, span, true)) if should_remove_import && import.is_nested() => {
291 self.add_suggestion_for_duplicate_nested_use(&mut err, import, span)
293 Some((import, _, true)) if should_remove_import && !import.is_glob() => {
294 // Simple case - remove the entire import. Due to the above match arm, this can
295 // only be a single use so just remove it entirely.
296 err.tool_only_span_suggestion(
297 import.use_span_with_attributes,
298 "remove unnecessary import",
300 Applicability::MaybeIncorrect,
303 Some((import, span, _)) => {
304 self.add_suggestion_for_rename_of_use(&mut err, name, import, span)
310 self.name_already_seen.insert(name, span);
313 /// This function adds a suggestion to change the binding name of a new import that conflicts
314 /// with an existing import.
316 /// ```text,ignore (diagnostic)
317 /// help: you can use `as` to change the binding name of the import
319 /// LL | use foo::bar as other_bar;
320 /// | ^^^^^^^^^^^^^^^^^^^^^
322 fn add_suggestion_for_rename_of_use(
324 err: &mut Diagnostic,
329 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
330 format!("Other{}", name)
332 format!("other_{}", name)
335 let mut suggestion = None;
337 ImportKind::Single { type_ns_only: true, .. } => {
338 suggestion = Some(format!("self as {}", suggested_name))
340 ImportKind::Single { source, .. } => {
342 source.span.hi().0.checked_sub(binding_span.lo().0).map(|pos| pos as usize)
344 if let Ok(snippet) = self.session.source_map().span_to_snippet(binding_span) {
345 if pos <= snippet.len() {
346 suggestion = Some(format!(
350 if snippet.ends_with(';') { ";" } else { "" }
356 ImportKind::ExternCrate { source, target } => {
357 suggestion = Some(format!(
358 "extern crate {} as {};",
359 source.unwrap_or(target.name),
366 let rename_msg = "you can use `as` to change the binding name of the import";
367 if let Some(suggestion) = suggestion {
372 Applicability::MaybeIncorrect,
375 err.span_label(binding_span, rename_msg);
379 /// This function adds a suggestion to remove an unnecessary binding from an import that is
380 /// nested. In the following example, this function will be invoked to remove the `a` binding
381 /// in the second use statement:
383 /// ```ignore (diagnostic)
384 /// use issue_52891::a;
385 /// use issue_52891::{d, a, e};
388 /// The following suggestion will be added:
390 /// ```ignore (diagnostic)
391 /// use issue_52891::{d, a, e};
392 /// ^-- help: remove unnecessary import
395 /// If the nested use contains only one import then the suggestion will remove the entire
398 /// It is expected that the provided import is nested - this isn't checked by the
399 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
400 /// as characters expected by span manipulations won't be present.
401 fn add_suggestion_for_duplicate_nested_use(
403 err: &mut Diagnostic,
407 assert!(import.is_nested());
408 let message = "remove unnecessary import";
410 // Two examples will be used to illustrate the span manipulations we're doing:
412 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
413 // `a` and `import.use_span` is `issue_52891::{d, a, e};`.
414 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
415 // `a` and `import.use_span` is `issue_52891::{d, e, a};`.
417 let (found_closing_brace, span) =
418 find_span_of_binding_until_next_binding(self.session, binding_span, import.use_span);
420 // If there was a closing brace then identify the span to remove any trailing commas from
422 if found_closing_brace {
423 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
424 err.tool_only_span_suggestion(span, message, "", Applicability::MaybeIncorrect);
426 // Remove the entire line if we cannot extend the span back, this indicates an
427 // `issue_52891::{self}` case.
429 import.use_span_with_attributes,
432 Applicability::MaybeIncorrect,
439 err.span_suggestion(span, message, "", Applicability::MachineApplicable);
442 pub(crate) fn lint_if_path_starts_with_module(
444 finalize: Option<Finalize>,
446 second_binding: Option<&NameBinding<'_>>,
448 let Some(Finalize { node_id, root_span, .. }) = finalize else {
452 let first_name = match path.get(0) {
453 // In the 2018 edition this lint is a hard error, so nothing to do
454 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
458 // We're only interested in `use` paths which should start with
459 // `{{root}}` currently.
460 if first_name != kw::PathRoot {
465 // If this import looks like `crate::...` it's already good
466 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
467 // Otherwise go below to see if it's an extern crate
469 // If the path has length one (and it's `PathRoot` most likely)
470 // then we don't know whether we're gonna be importing a crate or an
471 // item in our crate. Defer this lint to elsewhere
475 // If the first element of our path was actually resolved to an
476 // `ExternCrate` (also used for `crate::...`) then no need to issue a
477 // warning, this looks all good!
478 if let Some(binding) = second_binding {
479 if let NameBindingKind::Import { import, .. } = binding.kind {
480 // Careful: we still want to rewrite paths from renamed extern crates.
481 if let ImportKind::ExternCrate { source: None, .. } = import.kind {
487 let diag = BuiltinLintDiagnostics::AbsPathWithModule(root_span);
488 self.lint_buffer.buffer_lint_with_diagnostic(
489 ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
492 "absolute paths must start with `self`, `super`, \
493 `crate`, or an external crate name in the 2018 edition",
498 pub(crate) fn add_module_candidates(
501 names: &mut Vec<TypoSuggestion>,
502 filter_fn: &impl Fn(Res) -> bool,
503 ctxt: Option<SyntaxContext>,
505 for (key, resolution) in self.resolutions(module).borrow().iter() {
506 if let Some(binding) = resolution.borrow().binding {
507 let res = binding.res();
508 if filter_fn(res) && ctxt.map_or(true, |ctxt| ctxt == key.ident.span.ctxt()) {
509 names.push(TypoSuggestion::typo_from_ident(key.ident, res));
515 /// Combines an error with provided span and emits it.
517 /// This takes the error provided, combines it with the span and any additional spans inside the
518 /// error and emits it.
519 pub(crate) fn report_error(&mut self, span: Span, resolution_error: ResolutionError<'a>) {
520 self.into_struct_error(span, resolution_error).emit();
523 pub(crate) fn into_struct_error(
526 resolution_error: ResolutionError<'a>,
527 ) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
528 match resolution_error {
529 ResolutionError::GenericParamsFromOuterFunction(outer_res, has_generic_params) => {
530 let mut err = struct_span_err!(
534 "can't use generic parameters from outer function",
536 err.span_label(span, "use of generic parameter from outer function");
538 let sm = self.session.source_map();
539 let def_id = match outer_res {
540 Res::SelfTyParam { .. } => {
541 err.span_label(span, "can't use `Self` here");
544 Res::SelfTyAlias { alias_to: def_id, .. } => {
545 if let Some(impl_span) = self.opt_span(def_id) {
547 reduce_impl_span_to_impl_keyword(sm, impl_span),
548 "`Self` type implicitly declared here, by this `impl`",
551 err.span_label(span, "use a type here instead");
554 Res::Def(DefKind::TyParam, def_id) => {
555 if let Some(span) = self.opt_span(def_id) {
556 err.span_label(span, "type parameter from outer function");
560 Res::Def(DefKind::ConstParam, def_id) => {
561 if let Some(span) = self.opt_span(def_id) {
562 err.span_label(span, "const parameter from outer function");
568 "GenericParamsFromOuterFunction should only be used with \
569 Res::SelfTyParam, Res::SelfTyAlias, DefKind::TyParam or \
575 if let HasGenericParams::Yes(span) = has_generic_params {
576 // Try to retrieve the span of the function signature and generate a new
577 // message with a local type or const parameter.
578 let sugg_msg = "try using a local generic parameter instead";
579 let name = self.opt_name(def_id).unwrap_or(sym::T);
580 let (span, snippet) = if span.is_empty() {
581 let snippet = format!("<{}>", name);
584 let span = sm.span_through_char(span, '<').shrink_to_hi();
585 let snippet = format!("{}, ", name);
588 // Suggest the modification to the user
589 err.span_suggestion(span, sugg_msg, snippet, Applicability::MaybeIncorrect);
594 ResolutionError::NameAlreadyUsedInParameterList(name, first_use_span) => {
595 let mut err = struct_span_err!(
599 "the name `{}` is already used for a generic \
600 parameter in this item's generic parameters",
603 err.span_label(span, "already used");
604 err.span_label(first_use_span, format!("first use of `{}`", name));
607 ResolutionError::MethodNotMemberOfTrait(method, trait_, candidate) => {
608 let mut err = struct_span_err!(
612 "method `{}` 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 function with a similar name",
621 candidate.to_ident_string(),
622 Applicability::MaybeIncorrect,
627 ResolutionError::TypeNotMemberOfTrait(type_, trait_, candidate) => {
628 let mut err = struct_span_err!(
632 "type `{}` 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 type with a similar name",
641 candidate.to_ident_string(),
642 Applicability::MaybeIncorrect,
647 ResolutionError::ConstNotMemberOfTrait(const_, trait_, candidate) => {
648 let mut err = struct_span_err!(
652 "const `{}` is not a member of trait `{}`",
656 err.span_label(span, format!("not a member of trait `{}`", trait_));
657 if let Some(candidate) = candidate {
660 "there is an associated constant with a similar name",
661 candidate.to_ident_string(),
662 Applicability::MaybeIncorrect,
667 ResolutionError::VariableNotBoundInPattern(binding_error, parent_scope) => {
668 let BindingError { name, target, origin, could_be_path } = binding_error;
670 let target_sp = target.iter().copied().collect::<Vec<_>>();
671 let origin_sp = origin.iter().copied().collect::<Vec<_>>();
673 let msp = MultiSpan::from_spans(target_sp.clone());
674 let mut err = struct_span_err!(
678 "variable `{}` is not bound in all patterns",
681 for sp in target_sp {
682 err.span_label(sp, format!("pattern doesn't bind `{}`", name));
684 for sp in origin_sp {
685 err.span_label(sp, "variable not in all patterns");
688 let import_suggestions = self.lookup_import_candidates(
689 Ident::with_dummy_span(name),
692 &|res: Res| match res {
694 DefKind::Ctor(CtorOf::Variant, CtorKind::Const)
695 | DefKind::Ctor(CtorOf::Struct, CtorKind::Const)
697 | DefKind::AssocConst,
704 if import_suggestions.is_empty() {
705 let help_msg = format!(
706 "if you meant to match on a variant or a `const` item, consider \
707 making the path in the pattern qualified: `path::to::ModOrType::{}`",
710 err.span_help(span, &help_msg);
720 DiagnosticMode::Pattern,
726 ResolutionError::VariableBoundWithDifferentMode(variable_name, first_binding_span) => {
727 let mut err = struct_span_err!(
731 "variable `{}` is bound inconsistently across alternatives separated by `|`",
734 err.span_label(span, "bound in different ways");
735 err.span_label(first_binding_span, "first binding");
738 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
739 let mut err = struct_span_err!(
743 "identifier `{}` is bound more than once in this parameter list",
746 err.span_label(span, "used as parameter more than once");
749 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
750 let mut err = struct_span_err!(
754 "identifier `{}` is bound more than once in the same pattern",
757 err.span_label(span, "used in a pattern more than once");
760 ResolutionError::UndeclaredLabel { name, suggestion } => {
761 let mut err = struct_span_err!(
765 "use of undeclared label `{}`",
769 err.span_label(span, format!("undeclared label `{}`", name));
772 // A reachable label with a similar name exists.
773 Some((ident, true)) => {
774 err.span_label(ident.span, "a label with a similar name is reachable");
777 "try using similarly named label",
779 Applicability::MaybeIncorrect,
782 // An unreachable label with a similar name exists.
783 Some((ident, false)) => {
786 "a label with a similar name exists but is unreachable",
789 // No similarly-named labels exist.
795 ResolutionError::SelfImportsOnlyAllowedWithin { root, span_with_rename } => {
796 let mut err = struct_span_err!(
801 "`self` imports are only allowed within a { } list"
804 // None of the suggestions below would help with a case like `use self`.
806 // use foo::bar::self -> foo::bar
807 // use foo::bar::self as abc -> foo::bar as abc
810 "consider importing the module directly",
812 Applicability::MachineApplicable,
815 // use foo::bar::self -> foo::bar::{self}
816 // use foo::bar::self as abc -> foo::bar::{self as abc}
818 (span_with_rename.shrink_to_lo(), "{".to_string()),
819 (span_with_rename.shrink_to_hi(), "}".to_string()),
821 err.multipart_suggestion(
822 "alternatively, use the multi-path `use` syntax to import `self`",
824 Applicability::MachineApplicable,
829 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
830 let mut err = struct_span_err!(
834 "`self` import can only appear once in an import list"
836 err.span_label(span, "can only appear once in an import list");
839 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
840 let mut err = struct_span_err!(
844 "`self` import can only appear in an import list with \
847 err.span_label(span, "can only appear in an import list with a non-empty prefix");
850 ResolutionError::FailedToResolve { label, suggestion } => {
852 struct_span_err!(self.session, span, E0433, "failed to resolve: {}", &label);
853 err.span_label(span, label);
855 if let Some((suggestions, msg, applicability)) = suggestion {
856 if suggestions.is_empty() {
860 err.multipart_suggestion(&msg, suggestions, applicability);
865 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
866 let mut err = struct_span_err!(
871 "can't capture dynamic environment in a fn item"
873 err.help("use the `|| { ... }` closure form instead");
876 ResolutionError::AttemptToUseNonConstantValueInConstant(ident, sugg, current) => {
877 let mut err = struct_span_err!(
881 "attempt to use a non-constant value in a constant"
884 // ^^^ given this Span
885 // ------- get this Span to have an applicable suggestion
888 // only do this if the const and usage of the non-constant value are on the same line
889 // the further the two are apart, the higher the chance of the suggestion being wrong
894 .span_extend_to_prev_str(ident.span, current, true, false);
897 Some(sp) if !self.session.source_map().is_multiline(sp) => {
898 let sp = sp.with_lo(BytePos(sp.lo().0 - (current.len() as u32)));
901 &format!("consider using `{}` instead of `{}`", sugg, current),
902 format!("{} {}", sugg, ident),
903 Applicability::MaybeIncorrect,
905 err.span_label(span, "non-constant value");
908 err.span_label(ident.span, &format!("this would need to be a `{}`", sugg));
914 ResolutionError::BindingShadowsSomethingUnacceptable {
920 shadowed_binding_span,
922 let shadowed_binding_descr = shadowed_binding.descr();
923 let mut err = struct_span_err!(
927 "{}s cannot shadow {}s",
928 shadowing_binding.descr(),
929 shadowed_binding_descr,
933 format!("cannot be named the same as {} {}", article, shadowed_binding_descr),
935 match (shadowing_binding, shadowed_binding) {
937 PatternSource::Match,
938 Res::Def(DefKind::Ctor(CtorOf::Variant | CtorOf::Struct, CtorKind::Fn), _),
942 "try specify the pattern arguments",
943 format!("{}(..)", name),
944 Applicability::Unspecified,
950 format!("the {} `{}` is {} here", shadowed_binding_descr, name, participle);
951 err.span_label(shadowed_binding_span, msg);
954 ResolutionError::ForwardDeclaredGenericParam => {
955 let mut err = struct_span_err!(
959 "generic parameters with a default cannot use \
960 forward declared identifiers"
962 err.span_label(span, "defaulted generic parameters cannot be forward declared");
965 ResolutionError::ParamInTyOfConstParam(name) => {
966 let mut err = struct_span_err!(
970 "the type of const parameters must not depend on other generic parameters"
974 format!("the type must not depend on the parameter `{}`", name),
978 ResolutionError::ParamInNonTrivialAnonConst { name, is_type } => {
979 let mut err = self.session.struct_span_err(
981 "generic parameters may not be used in const operations",
983 err.span_label(span, &format!("cannot perform const operation using `{}`", name));
986 err.note("type parameters may not be used in const expressions");
989 "const parameters may only be used as standalone arguments, i.e. `{}`",
994 if self.session.is_nightly_build() {
996 "use `#![feature(generic_const_exprs)]` to allow generic const expressions",
1002 ResolutionError::SelfInGenericParamDefault => {
1003 let mut err = struct_span_err!(
1007 "generic parameters cannot use `Self` in their defaults"
1009 err.span_label(span, "`Self` in generic parameter default");
1012 ResolutionError::UnreachableLabel { name, definition_span, suggestion } => {
1013 let mut err = struct_span_err!(
1017 "use of unreachable label `{}`",
1021 err.span_label(definition_span, "unreachable label defined here");
1022 err.span_label(span, format!("unreachable label `{}`", name));
1024 "labels are unreachable through functions, closures, async blocks and modules",
1028 // A reachable label with a similar name exists.
1029 Some((ident, true)) => {
1030 err.span_label(ident.span, "a label with a similar name is reachable");
1031 err.span_suggestion(
1033 "try using similarly named label",
1035 Applicability::MaybeIncorrect,
1038 // An unreachable label with a similar name exists.
1039 Some((ident, false)) => {
1042 "a label with a similar name exists but is also unreachable",
1045 // No similarly-named labels exist.
1051 ResolutionError::TraitImplMismatch {
1058 let mut err = self.session.struct_span_err_with_code(
1061 "item `{}` is an associated {}, which doesn't match its trait `{}`",
1062 name, kind, trait_path,
1066 err.span_label(span, "does not match trait");
1067 err.span_label(trait_item_span, "item in trait");
1070 ResolutionError::TraitImplDuplicate { name, trait_item_span, old_span } => {
1071 let mut err = struct_span_err!(
1075 "duplicate definitions with name `{}`:",
1078 err.span_label(old_span, "previous definition here");
1079 err.span_label(trait_item_span, "item in trait");
1080 err.span_label(span, "duplicate definition");
1083 ResolutionError::InvalidAsmSym => {
1084 let mut err = self.session.struct_span_err(span, "invalid `sym` operand");
1085 err.span_label(span, "is a local variable");
1086 err.help("`sym` operands must refer to either a function or a static");
1092 pub(crate) fn report_vis_error(
1094 vis_resolution_error: VisResolutionError<'_>,
1095 ) -> ErrorGuaranteed {
1096 match vis_resolution_error {
1097 VisResolutionError::Relative2018(span, path) => {
1098 let mut err = self.session.struct_span_err(
1100 "relative paths are not supported in visibilities in 2018 edition or later",
1102 err.span_suggestion(
1105 format!("crate::{}", pprust::path_to_string(&path)),
1106 Applicability::MaybeIncorrect,
1110 VisResolutionError::AncestorOnly(span) => struct_span_err!(
1114 "visibilities can only be restricted to ancestor modules"
1116 VisResolutionError::FailedToResolve(span, label, suggestion) => {
1117 self.into_struct_error(span, ResolutionError::FailedToResolve { label, suggestion })
1119 VisResolutionError::ExpectedFound(span, path_str, res) => {
1120 let mut err = struct_span_err!(
1124 "expected module, found {} `{}`",
1128 err.span_label(span, "not a module");
1131 VisResolutionError::Indeterminate(span) => struct_span_err!(
1135 "cannot determine resolution for the visibility"
1137 VisResolutionError::ModuleOnly(span) => {
1138 self.session.struct_span_err(span, "visibility must resolve to a module")
1144 /// Lookup typo candidate in scope for a macro or import.
1145 fn early_lookup_typo_candidate(
1147 scope_set: ScopeSet<'a>,
1148 parent_scope: &ParentScope<'a>,
1150 filter_fn: &impl Fn(Res) -> bool,
1151 ) -> Option<TypoSuggestion> {
1152 let mut suggestions = Vec::new();
1153 let ctxt = ident.span.ctxt();
1154 self.visit_scopes(scope_set, parent_scope, ctxt, |this, scope, use_prelude, _| {
1156 Scope::DeriveHelpers(expn_id) => {
1157 let res = Res::NonMacroAttr(NonMacroAttrKind::DeriveHelper);
1164 .map(|ident| TypoSuggestion::typo_from_ident(*ident, res)),
1168 Scope::DeriveHelpersCompat => {
1169 let res = Res::NonMacroAttr(NonMacroAttrKind::DeriveHelperCompat);
1171 for derive in parent_scope.derives {
1172 let parent_scope = &ParentScope { derives: &[], ..*parent_scope };
1173 if let Ok((Some(ext), _)) = this.resolve_macro_path(
1175 Some(MacroKind::Derive),
1183 .map(|name| TypoSuggestion::typo_from_name(*name, res)),
1189 Scope::MacroRules(macro_rules_scope) => {
1190 if let MacroRulesScope::Binding(macro_rules_binding) = macro_rules_scope.get() {
1191 let res = macro_rules_binding.binding.res();
1193 suggestions.push(TypoSuggestion::typo_from_ident(
1194 macro_rules_binding.ident,
1200 Scope::CrateRoot => {
1201 let root_ident = Ident::new(kw::PathRoot, ident.span);
1202 let root_module = this.resolve_crate_root(root_ident);
1203 this.add_module_candidates(root_module, &mut suggestions, filter_fn, None);
1205 Scope::Module(module, _) => {
1206 this.add_module_candidates(module, &mut suggestions, filter_fn, None);
1208 Scope::MacroUsePrelude => {
1209 suggestions.extend(this.macro_use_prelude.iter().filter_map(
1211 let res = binding.res();
1212 filter_fn(res).then_some(TypoSuggestion::typo_from_name(*name, res))
1216 Scope::BuiltinAttrs => {
1217 let res = Res::NonMacroAttr(NonMacroAttrKind::Builtin(kw::Empty));
1222 .map(|attr| TypoSuggestion::typo_from_name(attr.name, res)),
1226 Scope::ExternPrelude => {
1227 suggestions.extend(this.extern_prelude.iter().filter_map(|(ident, _)| {
1228 let res = Res::Def(DefKind::Mod, CRATE_DEF_ID.to_def_id());
1229 filter_fn(res).then_some(TypoSuggestion::typo_from_ident(*ident, res))
1232 Scope::ToolPrelude => {
1233 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
1235 this.registered_tools
1237 .map(|ident| TypoSuggestion::typo_from_ident(*ident, res)),
1240 Scope::StdLibPrelude => {
1241 if let Some(prelude) = this.prelude {
1242 let mut tmp_suggestions = Vec::new();
1243 this.add_module_candidates(prelude, &mut tmp_suggestions, filter_fn, None);
1247 .filter(|s| use_prelude || this.is_builtin_macro(s.res)),
1251 Scope::BuiltinTypes => {
1252 suggestions.extend(PrimTy::ALL.iter().filter_map(|prim_ty| {
1253 let res = Res::PrimTy(*prim_ty);
1255 .then_some(TypoSuggestion::typo_from_name(prim_ty.name(), res))
1263 // Make sure error reporting is deterministic.
1264 suggestions.sort_by(|a, b| a.candidate.as_str().partial_cmp(b.candidate.as_str()).unwrap());
1266 match find_best_match_for_name(
1267 &suggestions.iter().map(|suggestion| suggestion.candidate).collect::<Vec<Symbol>>(),
1271 Some(found) if found != ident.name => {
1272 suggestions.into_iter().find(|suggestion| suggestion.candidate == found)
1278 fn lookup_import_candidates_from_module<FilterFn>(
1280 lookup_ident: Ident,
1281 namespace: Namespace,
1282 parent_scope: &ParentScope<'a>,
1283 start_module: Module<'a>,
1285 filter_fn: FilterFn,
1286 ) -> Vec<ImportSuggestion>
1288 FilterFn: Fn(Res) -> bool,
1290 let mut candidates = Vec::new();
1291 let mut seen_modules = FxHashSet::default();
1292 let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), true)];
1293 let mut worklist_via_import = vec![];
1295 while let Some((in_module, path_segments, accessible)) = match worklist.pop() {
1296 None => worklist_via_import.pop(),
1299 let in_module_is_extern = !in_module.def_id().is_local();
1300 // We have to visit module children in deterministic order to avoid
1301 // instabilities in reported imports (#43552).
1302 in_module.for_each_child(self, |this, ident, ns, name_binding| {
1303 // avoid non-importable candidates
1304 if !name_binding.is_importable() {
1308 let child_accessible =
1309 accessible && this.is_accessible_from(name_binding.vis, parent_scope.module);
1311 // do not venture inside inaccessible items of other crates
1312 if in_module_is_extern && !child_accessible {
1316 let via_import = name_binding.is_import() && !name_binding.is_extern_crate();
1318 // There is an assumption elsewhere that paths of variants are in the enum's
1319 // declaration and not imported. With this assumption, the variant component is
1320 // chopped and the rest of the path is assumed to be the enum's own path. For
1321 // errors where a variant is used as the type instead of the enum, this causes
1322 // funny looking invalid suggestions, i.e `foo` instead of `foo::MyEnum`.
1323 if via_import && name_binding.is_possibly_imported_variant() {
1327 // #90113: Do not count an inaccessible reexported item as a candidate.
1328 if let NameBindingKind::Import { binding, .. } = name_binding.kind {
1329 if this.is_accessible_from(binding.vis, parent_scope.module)
1330 && !this.is_accessible_from(name_binding.vis, parent_scope.module)
1336 // collect results based on the filter function
1337 // avoid suggesting anything from the same module in which we are resolving
1338 // avoid suggesting anything with a hygienic name
1339 if ident.name == lookup_ident.name
1341 && !ptr::eq(in_module, parent_scope.module)
1342 && !ident.span.normalize_to_macros_2_0().from_expansion()
1344 let res = name_binding.res();
1347 let mut segms = path_segments.clone();
1348 if lookup_ident.span.rust_2018() {
1349 // crate-local absolute paths start with `crate::` in edition 2018
1350 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
1351 segms.insert(0, ast::PathSegment::from_ident(crate_name));
1354 segms.push(ast::PathSegment::from_ident(ident));
1355 let path = Path { span: name_binding.span, segments: segms, tokens: None };
1356 let did = match res {
1357 Res::Def(DefKind::Ctor(..), did) => this.opt_parent(did),
1358 _ => res.opt_def_id(),
1361 if child_accessible {
1362 // Remove invisible match if exists
1363 if let Some(idx) = candidates
1365 .position(|v: &ImportSuggestion| v.did == did && !v.accessible)
1367 candidates.remove(idx);
1371 if candidates.iter().all(|v: &ImportSuggestion| v.did != did) {
1372 // See if we're recommending TryFrom, TryInto, or FromIterator and add
1373 // a note about editions
1374 let note = if let Some(did) = did {
1375 let requires_note = !did.is_local()
1376 && this.cstore().item_attrs_untracked(did, this.session).any(
1378 if attr.has_name(sym::rustc_diagnostic_item) {
1379 [sym::TryInto, sym::TryFrom, sym::FromIterator]
1381 .contains(&attr.value_str())
1388 requires_note.then(|| {
1390 "'{}' is included in the prelude starting in Edition 2021",
1391 path_names_to_string(&path)
1398 candidates.push(ImportSuggestion {
1402 accessible: child_accessible,
1409 // collect submodules to explore
1410 if let Some(module) = name_binding.module() {
1412 let mut path_segments = path_segments.clone();
1413 path_segments.push(ast::PathSegment::from_ident(ident));
1415 let is_extern_crate_that_also_appears_in_prelude =
1416 name_binding.is_extern_crate() && lookup_ident.span.rust_2018();
1418 if !is_extern_crate_that_also_appears_in_prelude {
1419 // add the module to the lookup
1420 if seen_modules.insert(module.def_id()) {
1421 if via_import { &mut worklist_via_import } else { &mut worklist }
1422 .push((module, path_segments, child_accessible));
1429 // If only some candidates are accessible, take just them
1430 if !candidates.iter().all(|v: &ImportSuggestion| !v.accessible) {
1431 candidates.retain(|x| x.accessible)
1437 /// When name resolution fails, this method can be used to look up candidate
1438 /// entities with the expected name. It allows filtering them using the
1439 /// supplied predicate (which should be used to only accept the types of
1440 /// definitions expected, e.g., traits). The lookup spans across all crates.
1442 /// N.B., the method does not look into imports, but this is not a problem,
1443 /// since we report the definitions (thus, the de-aliased imports).
1444 pub(crate) fn lookup_import_candidates<FilterFn>(
1446 lookup_ident: Ident,
1447 namespace: Namespace,
1448 parent_scope: &ParentScope<'a>,
1449 filter_fn: FilterFn,
1450 ) -> Vec<ImportSuggestion>
1452 FilterFn: Fn(Res) -> bool,
1454 let mut suggestions = self.lookup_import_candidates_from_module(
1459 Ident::with_dummy_span(kw::Crate),
1463 if lookup_ident.span.rust_2018() {
1464 let extern_prelude_names = self.extern_prelude.clone();
1465 for (ident, _) in extern_prelude_names.into_iter() {
1466 if ident.span.from_expansion() {
1467 // Idents are adjusted to the root context before being
1468 // resolved in the extern prelude, so reporting this to the
1469 // user is no help. This skips the injected
1470 // `extern crate std` in the 2018 edition, which would
1471 // otherwise cause duplicate suggestions.
1474 if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name) {
1475 let crate_root = self.expect_module(crate_id.as_def_id());
1476 suggestions.extend(self.lookup_import_candidates_from_module(
1491 pub(crate) fn unresolved_macro_suggestions(
1493 err: &mut Diagnostic,
1494 macro_kind: MacroKind,
1495 parent_scope: &ParentScope<'a>,
1498 let is_expected = &|res: Res| res.macro_kind() == Some(macro_kind);
1499 let suggestion = self.early_lookup_typo_candidate(
1500 ScopeSet::Macro(macro_kind),
1505 self.add_typo_suggestion(err, suggestion, ident.span);
1507 let import_suggestions =
1508 self.lookup_import_candidates(ident, Namespace::MacroNS, parent_scope, is_expected);
1514 &import_suggestions,
1517 DiagnosticMode::Normal,
1521 if macro_kind == MacroKind::Derive && (ident.name == sym::Send || ident.name == sym::Sync) {
1522 let msg = format!("unsafe traits like `{}` should be implemented explicitly", ident);
1523 err.span_note(ident.span, &msg);
1526 if self.macro_names.contains(&ident.normalize_to_macros_2_0()) {
1527 err.help("have you added the `#[macro_use]` on the module/import?");
1530 if ident.name == kw::Default
1531 && let ModuleKind::Def(DefKind::Enum, def_id, _) = parent_scope.module.kind
1532 && let Some(span) = self.opt_span(def_id)
1534 let source_map = self.session.source_map();
1535 let head_span = source_map.guess_head_span(span);
1536 if let Ok(head) = source_map.span_to_snippet(head_span) {
1537 err.span_suggestion(head_span, "consider adding a derive", format!("#[derive(Default)]\n{head}"), Applicability::MaybeIncorrect);
1541 "consider adding `#[derive(Default)]` to this enum",
1545 for ns in [Namespace::MacroNS, Namespace::TypeNS, Namespace::ValueNS] {
1546 if let Ok(binding) = self.early_resolve_ident_in_lexical_scope(
1548 ScopeSet::All(ns, false),
1554 let desc = match binding.res() {
1555 Res::Def(DefKind::Macro(MacroKind::Bang), _) => {
1556 "a function-like macro".to_string()
1558 Res::Def(DefKind::Macro(MacroKind::Attr), _) | Res::NonMacroAttr(..) => {
1559 format!("an attribute: `#[{}]`", ident)
1561 Res::Def(DefKind::Macro(MacroKind::Derive), _) => {
1562 format!("a derive macro: `#[derive({})]`", ident)
1565 // Don't confuse the user with tool modules.
1568 Res::Def(DefKind::Trait, _) if macro_kind == MacroKind::Derive => {
1569 "only a trait, without a derive macro".to_string()
1575 macro_kind.article(),
1576 macro_kind.descr_expected(),
1579 if let crate::NameBindingKind::Import { import, .. } = binding.kind {
1580 if !import.span.is_dummy() {
1583 &format!("`{}` is imported here, but it is {}", ident, desc),
1585 // Silence the 'unused import' warning we might get,
1586 // since this diagnostic already covers that import.
1587 self.record_use(ident, binding, false);
1591 err.note(&format!("`{}` is in scope, but it is {}", ident, desc));
1597 pub(crate) fn add_typo_suggestion(
1599 err: &mut Diagnostic,
1600 suggestion: Option<TypoSuggestion>,
1603 let suggestion = match suggestion {
1604 None => return false,
1605 // We shouldn't suggest underscore.
1606 Some(suggestion) if suggestion.candidate == kw::Underscore => return false,
1607 Some(suggestion) => suggestion,
1609 let def_span = suggestion.res.opt_def_id().and_then(|def_id| match def_id.krate {
1610 LOCAL_CRATE => self.opt_span(def_id),
1611 _ => Some(self.cstore().get_span_untracked(def_id, self.session)),
1613 if let Some(def_span) = def_span {
1614 if span.overlaps(def_span) {
1615 // Don't suggest typo suggestion for itself like in the following:
1616 // error[E0423]: expected function, tuple struct or tuple variant, found struct `X`
1617 // --> $DIR/issue-64792-bad-unicode-ctor.rs:3:14
1620 // | ----------- `X` defined here
1622 // LL | const Y: X = X("ö");
1623 // | -------------^^^^^^- similarly named constant `Y` defined here
1625 // help: use struct literal syntax instead
1627 // LL | const Y: X = X {};
1629 // help: a constant with a similar name exists
1631 // LL | const Y: X = Y("ö");
1635 let prefix = match suggestion.target {
1636 SuggestionTarget::SimilarlyNamed => "similarly named ",
1637 SuggestionTarget::SingleItem => "",
1641 self.session.source_map().guess_head_span(def_span),
1643 "{}{} `{}` defined here",
1645 suggestion.res.descr(),
1646 suggestion.candidate,
1650 let msg = match suggestion.target {
1651 SuggestionTarget::SimilarlyNamed => format!(
1652 "{} {} with a similar name exists",
1653 suggestion.res.article(),
1654 suggestion.res.descr()
1656 SuggestionTarget::SingleItem => {
1657 format!("maybe you meant this {}", suggestion.res.descr())
1660 err.span_suggestion(span, &msg, suggestion.candidate, Applicability::MaybeIncorrect);
1664 fn binding_description(&self, b: &NameBinding<'_>, ident: Ident, from_prelude: bool) -> String {
1666 if b.span.is_dummy() || !self.session.source_map().is_span_accessible(b.span) {
1667 // These already contain the "built-in" prefix or look bad with it.
1669 !matches!(b.res(), Res::NonMacroAttr(..) | Res::PrimTy(..) | Res::ToolMod);
1670 let (built_in, from) = if from_prelude {
1671 ("", " from prelude")
1672 } else if b.is_extern_crate()
1674 && self.session.opts.externs.get(ident.as_str()).is_some()
1676 ("", " passed with `--extern`")
1677 } else if add_built_in {
1683 let a = if built_in.is_empty() { res.article() } else { "a" };
1684 format!("{a}{built_in} {thing}{from}", thing = res.descr())
1686 let introduced = if b.is_import() { "imported" } else { "defined" };
1687 format!("the {thing} {introduced} here", thing = res.descr())
1691 fn report_ambiguity_error(&self, ambiguity_error: &AmbiguityError<'_>) {
1692 let AmbiguityError { kind, ident, b1, b2, misc1, misc2 } = *ambiguity_error;
1693 let (b1, b2, misc1, misc2, swapped) = if b2.span.is_dummy() && !b1.span.is_dummy() {
1694 // We have to print the span-less alternative first, otherwise formatting looks bad.
1695 (b2, b1, misc2, misc1, true)
1697 (b1, b2, misc1, misc2, false)
1700 let mut err = struct_span_err!(self.session, ident.span, E0659, "`{ident}` is ambiguous");
1701 err.span_label(ident.span, "ambiguous name");
1702 err.note(&format!("ambiguous because of {}", kind.descr()));
1704 let mut could_refer_to = |b: &NameBinding<'_>, misc: AmbiguityErrorMisc, also: &str| {
1705 let what = self.binding_description(b, ident, misc == AmbiguityErrorMisc::FromPrelude);
1706 let note_msg = format!("`{ident}` could{also} refer to {what}");
1708 let thing = b.res().descr();
1709 let mut help_msgs = Vec::new();
1710 if b.is_glob_import()
1711 && (kind == AmbiguityKind::GlobVsGlob
1712 || kind == AmbiguityKind::GlobVsExpanded
1713 || kind == AmbiguityKind::GlobVsOuter && swapped != also.is_empty())
1715 help_msgs.push(format!(
1716 "consider adding an explicit import of `{ident}` to disambiguate"
1719 if b.is_extern_crate() && ident.span.rust_2018() {
1720 help_msgs.push(format!("use `::{ident}` to refer to this {thing} unambiguously"))
1722 if misc == AmbiguityErrorMisc::SuggestCrate {
1724 .push(format!("use `crate::{ident}` to refer to this {thing} unambiguously"))
1725 } else if misc == AmbiguityErrorMisc::SuggestSelf {
1727 .push(format!("use `self::{ident}` to refer to this {thing} unambiguously"))
1730 err.span_note(b.span, ¬e_msg);
1731 for (i, help_msg) in help_msgs.iter().enumerate() {
1732 let or = if i == 0 { "" } else { "or " };
1733 err.help(&format!("{}{}", or, help_msg));
1737 could_refer_to(b1, misc1, "");
1738 could_refer_to(b2, misc2, " also");
1742 /// If the binding refers to a tuple struct constructor with fields,
1743 /// returns the span of its fields.
1744 fn ctor_fields_span(&self, binding: &NameBinding<'_>) -> Option<Span> {
1745 if let NameBindingKind::Res(
1746 Res::Def(DefKind::Ctor(CtorOf::Struct, CtorKind::Fn), ctor_def_id),
1750 let def_id = self.parent(ctor_def_id);
1751 let fields = self.field_names.get(&def_id)?;
1752 return fields.iter().map(|name| name.span).reduce(Span::to); // None for `struct Foo()`
1757 fn report_privacy_error(&self, privacy_error: &PrivacyError<'_>) {
1758 let PrivacyError { ident, binding, .. } = *privacy_error;
1760 let res = binding.res();
1761 let ctor_fields_span = self.ctor_fields_span(binding);
1762 let plain_descr = res.descr().to_string();
1763 let nonimport_descr =
1764 if ctor_fields_span.is_some() { plain_descr + " constructor" } else { plain_descr };
1765 let import_descr = nonimport_descr.clone() + " import";
1767 |b: &NameBinding<'_>| if b.is_import() { &import_descr } else { &nonimport_descr };
1769 // Print the primary message.
1770 let descr = get_descr(binding);
1772 struct_span_err!(self.session, ident.span, E0603, "{} `{}` is private", descr, ident);
1773 err.span_label(ident.span, &format!("private {}", descr));
1774 if let Some(span) = ctor_fields_span {
1775 err.span_label(span, "a constructor is private if any of the fields is private");
1778 // Print the whole import chain to make it easier to see what happens.
1779 let first_binding = binding;
1780 let mut next_binding = Some(binding);
1781 let mut next_ident = ident;
1782 while let Some(binding) = next_binding {
1783 let name = next_ident;
1784 next_binding = match binding.kind {
1785 _ if res == Res::Err => None,
1786 NameBindingKind::Import { binding, import, .. } => match import.kind {
1787 _ if binding.span.is_dummy() => None,
1788 ImportKind::Single { source, .. } => {
1789 next_ident = source;
1792 ImportKind::Glob { .. } | ImportKind::MacroUse => Some(binding),
1793 ImportKind::ExternCrate { .. } => None,
1798 let first = ptr::eq(binding, first_binding);
1800 "{and_refers_to}the {item} `{name}`{which} is defined here{dots}",
1801 and_refers_to = if first { "" } else { "...and refers to " },
1802 item = get_descr(binding),
1803 which = if first { "" } else { " which" },
1804 dots = if next_binding.is_some() { "..." } else { "" },
1806 let def_span = self.session.source_map().guess_head_span(binding.span);
1807 let mut note_span = MultiSpan::from_span(def_span);
1808 if !first && binding.vis.is_public() {
1809 note_span.push_span_label(def_span, "consider importing it directly");
1811 err.span_note(note_span, &msg);
1817 pub(crate) fn find_similarly_named_module_or_crate(
1820 current_module: &Module<'a>,
1821 ) -> Option<Symbol> {
1822 let mut candidates = self
1825 .map(|(ident, _)| ident.name)
1829 .filter(|(_, module)| {
1830 current_module.is_ancestor_of(module) && !ptr::eq(current_module, *module)
1832 .flat_map(|(_, module)| module.kind.name()),
1834 .filter(|c| !c.to_string().is_empty())
1835 .collect::<Vec<_>>();
1838 match find_best_match_for_name(&candidates, ident, None) {
1839 Some(sugg) if sugg == ident => None,
1844 pub(crate) fn report_path_resolution_error(
1847 opt_ns: Option<Namespace>, // `None` indicates a module path in import
1848 parent_scope: &ParentScope<'a>,
1849 ribs: Option<&PerNS<Vec<Rib<'a>>>>,
1850 ignore_binding: Option<&'a NameBinding<'a>>,
1851 module: Option<ModuleOrUniformRoot<'a>>,
1854 ) -> (String, Option<Suggestion>) {
1855 let is_last = i == path.len() - 1;
1856 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
1857 let module_res = match module {
1858 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
1861 if module_res == self.graph_root.res() {
1862 let is_mod = |res| matches!(res, Res::Def(DefKind::Mod, _));
1863 let mut candidates = self.lookup_import_candidates(ident, TypeNS, parent_scope, is_mod);
1865 .sort_by_cached_key(|c| (c.path.segments.len(), pprust::path_to_string(&c.path)));
1866 if let Some(candidate) = candidates.get(0) {
1868 String::from("unresolved import"),
1870 vec![(ident.span, pprust::path_to_string(&candidate.path))],
1871 String::from("a similar path exists"),
1872 Applicability::MaybeIncorrect,
1875 } else if self.session.edition() == Edition::Edition2015 {
1877 format!("maybe a missing crate `{ident}`?"),
1881 "consider adding `extern crate {ident}` to use the `{ident}` crate"
1883 Applicability::MaybeIncorrect,
1887 (format!("could not find `{ident}` in the crate root"), None)
1890 let parent = path[i - 1].ident.name;
1891 let parent = match parent {
1892 // ::foo is mounted at the crate root for 2015, and is the extern
1893 // prelude for 2018+
1894 kw::PathRoot if self.session.edition() > Edition::Edition2015 => {
1895 "the list of imported crates".to_owned()
1897 kw::PathRoot | kw::Crate => "the crate root".to_owned(),
1898 _ => format!("`{parent}`"),
1901 let mut msg = format!("could not find `{}` in {}", ident, parent);
1902 if ns == TypeNS || ns == ValueNS {
1903 let ns_to_try = if ns == TypeNS { ValueNS } else { TypeNS };
1904 let binding = if let Some(module) = module {
1905 self.resolve_ident_in_module(
1913 } else if let Some(ribs) = ribs
1914 && let Some(TypeNS | ValueNS) = opt_ns
1916 match self.resolve_ident_in_lexical_scope(
1924 // we found a locally-imported or available item/module
1925 Some(LexicalScopeBinding::Item(binding)) => Some(binding),
1929 let scopes = ScopeSet::All(ns_to_try, opt_ns.is_none());
1930 self.early_resolve_ident_in_lexical_scope(
1939 if let Some(binding) = binding {
1940 let mut found = |what| {
1942 "expected {}, found {} `{}` in {}",
1949 if binding.module().is_some() {
1952 match binding.res() {
1953 Res::Def(kind, id) => found(kind.descr(id)),
1954 _ => found(ns_to_try.descr()),
1960 } else if ident.name == kw::SelfUpper {
1961 ("`Self` is only available in impls, traits, and type definitions".to_string(), None)
1962 } else if ident.name.as_str().chars().next().map_or(false, |c| c.is_ascii_uppercase()) {
1963 // Check whether the name refers to an item in the value namespace.
1964 let binding = if let Some(ribs) = ribs {
1965 self.resolve_ident_in_lexical_scope(
1976 let match_span = match binding {
1977 // Name matches a local variable. For example:
1980 // let Foo: &str = "";
1981 // println!("{}", Foo::Bar); // Name refers to local
1982 // // variable `Foo`.
1985 Some(LexicalScopeBinding::Res(Res::Local(id))) => {
1986 Some(*self.pat_span_map.get(&id).unwrap())
1988 // Name matches item from a local name binding
1989 // created by `use` declaration. For example:
1991 // pub Foo: &str = "";
1995 // println!("{}", Foo::Bar); // Name refers to local
1996 // // binding `Foo`.
1999 Some(LexicalScopeBinding::Item(name_binding)) => Some(name_binding.span),
2002 let suggestion = if let Some(span) = match_span {
2004 vec![(span, String::from(""))],
2005 format!("`{}` is defined here, but is not a type", ident),
2006 Applicability::MaybeIncorrect,
2012 (format!("use of undeclared type `{}`", ident), suggestion)
2014 let suggestion = if ident.name == sym::alloc {
2017 String::from("add `extern crate alloc` to use the `alloc` crate"),
2018 Applicability::MaybeIncorrect,
2021 self.find_similarly_named_module_or_crate(ident.name, &parent_scope.module).map(
2024 vec![(ident.span, sugg.to_string())],
2025 String::from("there is a crate or module with a similar name"),
2026 Applicability::MaybeIncorrect,
2031 (format!("use of undeclared crate or module `{}`", ident), suggestion)
2036 impl<'a, 'b> ImportResolver<'a, 'b> {
2037 /// Adds suggestions for a path that cannot be resolved.
2038 pub(crate) fn make_path_suggestion(
2041 mut path: Vec<Segment>,
2042 parent_scope: &ParentScope<'b>,
2043 ) -> Option<(Vec<Segment>, Option<String>)> {
2044 debug!("make_path_suggestion: span={:?} path={:?}", span, path);
2046 match (path.get(0), path.get(1)) {
2047 // `{{root}}::ident::...` on both editions.
2048 // On 2015 `{{root}}` is usually added implicitly.
2049 (Some(fst), Some(snd))
2050 if fst.ident.name == kw::PathRoot && !snd.ident.is_path_segment_keyword() => {}
2051 // `ident::...` on 2018.
2053 if fst.ident.span.rust_2018() && !fst.ident.is_path_segment_keyword() =>
2055 // Insert a placeholder that's later replaced by `self`/`super`/etc.
2056 path.insert(0, Segment::from_ident(Ident::empty()));
2061 self.make_missing_self_suggestion(path.clone(), parent_scope)
2062 .or_else(|| self.make_missing_crate_suggestion(path.clone(), parent_scope))
2063 .or_else(|| self.make_missing_super_suggestion(path.clone(), parent_scope))
2064 .or_else(|| self.make_external_crate_suggestion(path, parent_scope))
2067 /// Suggest a missing `self::` if that resolves to an correct module.
2071 /// LL | use foo::Bar;
2072 /// | ^^^ did you mean `self::foo`?
2074 fn make_missing_self_suggestion(
2076 mut path: Vec<Segment>,
2077 parent_scope: &ParentScope<'b>,
2078 ) -> Option<(Vec<Segment>, Option<String>)> {
2079 // Replace first ident with `self` and check if that is valid.
2080 path[0].ident.name = kw::SelfLower;
2081 let result = self.r.maybe_resolve_path(&path, None, parent_scope);
2082 debug!("make_missing_self_suggestion: path={:?} result={:?}", path, result);
2083 if let PathResult::Module(..) = result { Some((path, None)) } else { None }
2086 /// Suggests a missing `crate::` if that resolves to an correct module.
2090 /// LL | use foo::Bar;
2091 /// | ^^^ did you mean `crate::foo`?
2093 fn make_missing_crate_suggestion(
2095 mut path: Vec<Segment>,
2096 parent_scope: &ParentScope<'b>,
2097 ) -> Option<(Vec<Segment>, Option<String>)> {
2098 // Replace first ident with `crate` and check if that is valid.
2099 path[0].ident.name = kw::Crate;
2100 let result = self.r.maybe_resolve_path(&path, None, parent_scope);
2101 debug!("make_missing_crate_suggestion: path={:?} result={:?}", path, result);
2102 if let PathResult::Module(..) = result {
2106 "`use` statements changed in Rust 2018; read more at \
2107 <https://doc.rust-lang.org/edition-guide/rust-2018/module-system/path-\
2117 /// Suggests a missing `super::` if that resolves to an correct module.
2121 /// LL | use foo::Bar;
2122 /// | ^^^ did you mean `super::foo`?
2124 fn make_missing_super_suggestion(
2126 mut path: Vec<Segment>,
2127 parent_scope: &ParentScope<'b>,
2128 ) -> Option<(Vec<Segment>, Option<String>)> {
2129 // Replace first ident with `crate` and check if that is valid.
2130 path[0].ident.name = kw::Super;
2131 let result = self.r.maybe_resolve_path(&path, None, parent_scope);
2132 debug!("make_missing_super_suggestion: path={:?} result={:?}", path, result);
2133 if let PathResult::Module(..) = result { Some((path, None)) } else { None }
2136 /// Suggests a missing external crate name if that resolves to an correct module.
2140 /// LL | use foobar::Baz;
2141 /// | ^^^^^^ did you mean `baz::foobar`?
2144 /// Used when importing a submodule of an external crate but missing that crate's
2145 /// name as the first part of path.
2146 fn make_external_crate_suggestion(
2148 mut path: Vec<Segment>,
2149 parent_scope: &ParentScope<'b>,
2150 ) -> Option<(Vec<Segment>, Option<String>)> {
2151 if path[1].ident.span.rust_2015() {
2155 // Sort extern crate names in *reverse* order to get
2156 // 1) some consistent ordering for emitted diagnostics, and
2157 // 2) `std` suggestions before `core` suggestions.
2158 let mut extern_crate_names =
2159 self.r.extern_prelude.iter().map(|(ident, _)| ident.name).collect::<Vec<_>>();
2160 extern_crate_names.sort_by(|a, b| b.as_str().partial_cmp(a.as_str()).unwrap());
2162 for name in extern_crate_names.into_iter() {
2163 // Replace first ident with a crate name and check if that is valid.
2164 path[0].ident.name = name;
2165 let result = self.r.maybe_resolve_path(&path, None, parent_scope);
2167 "make_external_crate_suggestion: name={:?} path={:?} result={:?}",
2170 if let PathResult::Module(..) = result {
2171 return Some((path, None));
2178 /// Suggests importing a macro from the root of the crate rather than a module within
2182 /// help: a macro with this name exists at the root of the crate
2184 /// LL | use issue_59764::makro;
2185 /// | ^^^^^^^^^^^^^^^^^^
2187 /// = note: this could be because a macro annotated with `#[macro_export]` will be exported
2188 /// at the root of the crate instead of the module where it is defined
2190 pub(crate) fn check_for_module_export_macro(
2192 import: &'b Import<'b>,
2193 module: ModuleOrUniformRoot<'b>,
2195 ) -> Option<(Option<Suggestion>, Option<String>)> {
2196 let ModuleOrUniformRoot::Module(mut crate_module) = module else {
2200 while let Some(parent) = crate_module.parent {
2201 crate_module = parent;
2204 if ModuleOrUniformRoot::same_def(ModuleOrUniformRoot::Module(crate_module), module) {
2205 // Don't make a suggestion if the import was already from the root of the
2210 let resolutions = self.r.resolutions(crate_module).borrow();
2211 let resolution = resolutions.get(&self.r.new_key(ident, MacroNS))?;
2212 let binding = resolution.borrow().binding()?;
2213 if let Res::Def(DefKind::Macro(MacroKind::Bang), _) = binding.res() {
2214 let module_name = crate_module.kind.name().unwrap();
2215 let import_snippet = match import.kind {
2216 ImportKind::Single { source, target, .. } if source != target => {
2217 format!("{} as {}", source, target)
2219 _ => format!("{}", ident),
2222 let mut corrections: Vec<(Span, String)> = Vec::new();
2223 if !import.is_nested() {
2224 // Assume this is the easy case of `use issue_59764::foo::makro;` and just remove
2225 // intermediate segments.
2226 corrections.push((import.span, format!("{}::{}", module_name, import_snippet)));
2228 // Find the binding span (and any trailing commas and spaces).
2229 // ie. `use a::b::{c, d, e};`
2231 let (found_closing_brace, binding_span) = find_span_of_binding_until_next_binding(
2237 "check_for_module_export_macro: found_closing_brace={:?} binding_span={:?}",
2238 found_closing_brace, binding_span
2241 let mut removal_span = binding_span;
2242 if found_closing_brace {
2243 // If the binding span ended with a closing brace, as in the below example:
2244 // ie. `use a::b::{c, d};`
2246 // Then expand the span of characters to remove to include the previous
2247 // binding's trailing comma.
2248 // ie. `use a::b::{c, d};`
2250 if let Some(previous_span) =
2251 extend_span_to_previous_binding(self.r.session, binding_span)
2253 debug!("check_for_module_export_macro: previous_span={:?}", previous_span);
2254 removal_span = removal_span.with_lo(previous_span.lo());
2257 debug!("check_for_module_export_macro: removal_span={:?}", removal_span);
2259 // Remove the `removal_span`.
2260 corrections.push((removal_span, "".to_string()));
2262 // Find the span after the crate name and if it has nested imports immediately
2263 // after the crate name already.
2264 // ie. `use a::b::{c, d};`
2266 // or `use a::{b, c, d}};`
2268 let (has_nested, after_crate_name) = find_span_immediately_after_crate_name(
2274 "check_for_module_export_macro: has_nested={:?} after_crate_name={:?}",
2275 has_nested, after_crate_name
2278 let source_map = self.r.session.source_map();
2280 // Add the import to the start, with a `{` if required.
2281 let start_point = source_map.start_point(after_crate_name);
2282 if let Ok(start_snippet) = source_map.span_to_snippet(start_point) {
2286 // In this case, `start_snippet` must equal '{'.
2287 format!("{}{}, ", start_snippet, import_snippet)
2289 // In this case, add a `{`, then the moved import, then whatever
2290 // was there before.
2291 format!("{{{}, {}", import_snippet, start_snippet)
2296 // Add a `};` to the end if nested, matching the `{` added at the start.
2298 corrections.push((source_map.end_point(after_crate_name), "};".to_string()));
2302 let suggestion = Some((
2304 String::from("a macro with this name exists at the root of the crate"),
2305 Applicability::MaybeIncorrect,
2307 Some((suggestion, Some("this could be because a macro annotated with `#[macro_export]` will be exported \
2308 at the root of the crate instead of the module where it is defined"
2316 /// Given a `binding_span` of a binding within a use statement:
2318 /// ```ignore (illustrative)
2319 /// use foo::{a, b, c};
2323 /// then return the span until the next binding or the end of the statement:
2325 /// ```ignore (illustrative)
2326 /// use foo::{a, b, c};
2329 fn find_span_of_binding_until_next_binding(
2334 let source_map = sess.source_map();
2336 // Find the span of everything after the binding.
2337 // ie. `a, e};` or `a};`
2338 let binding_until_end = binding_span.with_hi(use_span.hi());
2340 // Find everything after the binding but not including the binding.
2341 // ie. `, e};` or `};`
2342 let after_binding_until_end = binding_until_end.with_lo(binding_span.hi());
2344 // Keep characters in the span until we encounter something that isn't a comma or
2348 // Also note whether a closing brace character was encountered. If there
2349 // was, then later go backwards to remove any trailing commas that are left.
2350 let mut found_closing_brace = false;
2351 let after_binding_until_next_binding =
2352 source_map.span_take_while(after_binding_until_end, |&ch| {
2354 found_closing_brace = true;
2356 ch == ' ' || ch == ','
2359 // Combine the two spans.
2360 // ie. `a, ` or `a`.
2362 // Removing these would leave `issue_52891::{d, e};` or `issue_52891::{d, e, };`
2363 let span = binding_span.with_hi(after_binding_until_next_binding.hi());
2365 (found_closing_brace, span)
2368 /// Given a `binding_span`, return the span through to the comma or opening brace of the previous
2371 /// ```ignore (illustrative)
2372 /// use foo::a::{a, b, c};
2373 /// // ^^--- binding span
2375 /// // returned span
2377 /// use foo::{a, b, c};
2378 /// // --- binding span
2380 fn extend_span_to_previous_binding(sess: &Session, binding_span: Span) -> Option<Span> {
2381 let source_map = sess.source_map();
2383 // `prev_source` will contain all of the source that came before the span.
2384 // Then split based on a command and take the first (ie. closest to our span)
2385 // snippet. In the example, this is a space.
2386 let prev_source = source_map.span_to_prev_source(binding_span).ok()?;
2388 let prev_comma = prev_source.rsplit(',').collect::<Vec<_>>();
2389 let prev_starting_brace = prev_source.rsplit('{').collect::<Vec<_>>();
2390 if prev_comma.len() <= 1 || prev_starting_brace.len() <= 1 {
2394 let prev_comma = prev_comma.first().unwrap();
2395 let prev_starting_brace = prev_starting_brace.first().unwrap();
2397 // If the amount of source code before the comma is greater than
2398 // the amount of source code before the starting brace then we've only
2399 // got one item in the nested item (eg. `issue_52891::{self}`).
2400 if prev_comma.len() > prev_starting_brace.len() {
2404 Some(binding_span.with_lo(BytePos(
2405 // Take away the number of bytes for the characters we've found and an
2406 // extra for the comma.
2407 binding_span.lo().0 - (prev_comma.as_bytes().len() as u32) - 1,
2411 /// Given a `use_span` of a binding within a use statement, returns the highlighted span and if
2412 /// it is a nested use tree.
2414 /// ```ignore (illustrative)
2415 /// use foo::a::{b, c};
2416 /// // ^^^^^^^^^^ -- false
2418 /// use foo::{a, b, c};
2419 /// // ^^^^^^^^^^ -- true
2421 /// use foo::{a, b::{c, d}};
2422 /// // ^^^^^^^^^^^^^^^ -- true
2424 fn find_span_immediately_after_crate_name(
2426 module_name: Symbol,
2430 "find_span_immediately_after_crate_name: module_name={:?} use_span={:?}",
2431 module_name, use_span
2433 let source_map = sess.source_map();
2435 // Using `use issue_59764::foo::{baz, makro};` as an example throughout..
2436 let mut num_colons = 0;
2437 // Find second colon.. `use issue_59764:`
2438 let until_second_colon = source_map.span_take_while(use_span, |c| {
2442 !matches!(c, ':' if num_colons == 2)
2444 // Find everything after the second colon.. `foo::{baz, makro};`
2445 let from_second_colon = use_span.with_lo(until_second_colon.hi() + BytePos(1));
2447 let mut found_a_non_whitespace_character = false;
2448 // Find the first non-whitespace character in `from_second_colon`.. `f`
2449 let after_second_colon = source_map.span_take_while(from_second_colon, |c| {
2450 if found_a_non_whitespace_character {
2453 if !c.is_whitespace() {
2454 found_a_non_whitespace_character = true;
2459 // Find the first `{` in from_second_colon.. `foo::{`
2460 let next_left_bracket = source_map.span_through_char(from_second_colon, '{');
2462 (next_left_bracket == after_second_colon, from_second_colon)
2465 /// A suggestion has already been emitted, change the wording slightly to clarify that both are
2466 /// independent options.
2472 /// Whether an existing place with an `use` item was found.
2478 /// Whether a binding is part of a pattern or a use statement. Used for diagnostics.
2479 enum DiagnosticMode {
2481 /// The binding is part of a pattern
2483 /// The binding is part of a use statement
2487 pub(crate) fn import_candidates(
2489 source_span: &IndexVec<LocalDefId, Span>,
2490 err: &mut Diagnostic,
2491 // This is `None` if all placement locations are inside expansions
2492 use_placement_span: Option<Span>,
2493 candidates: &[ImportSuggestion],
2503 DiagnosticMode::Import,
2508 /// When an entity with a given name is not available in scope, we search for
2509 /// entities with that name in all crates. This method allows outputting the
2510 /// results of this search in a programmer-friendly way
2513 source_span: &IndexVec<LocalDefId, Span>,
2514 err: &mut Diagnostic,
2515 // This is `None` if all placement locations are inside expansions
2516 use_placement_span: Option<Span>,
2517 candidates: &[ImportSuggestion],
2519 found_use: FoundUse,
2520 mode: DiagnosticMode,
2523 if candidates.is_empty() {
2527 let mut accessible_path_strings: Vec<(String, &str, Option<DefId>, &Option<String>)> =
2529 let mut inaccessible_path_strings: Vec<(String, &str, Option<DefId>, &Option<String>)> =
2532 candidates.iter().for_each(|c| {
2533 (if c.accessible { &mut accessible_path_strings } else { &mut inaccessible_path_strings })
2534 .push((path_names_to_string(&c.path), c.descr, c.did, &c.note))
2537 // we want consistent results across executions, but candidates are produced
2538 // by iterating through a hash map, so make sure they are ordered:
2539 for path_strings in [&mut accessible_path_strings, &mut inaccessible_path_strings] {
2540 path_strings.sort_by(|a, b| a.0.cmp(&b.0));
2541 let core_path_strings =
2542 path_strings.drain_filter(|p| p.0.starts_with("core::")).collect::<Vec<_>>();
2543 path_strings.extend(core_path_strings);
2544 path_strings.dedup_by(|a, b| a.0 == b.0);
2547 if !accessible_path_strings.is_empty() {
2548 let (determiner, kind, name) = if accessible_path_strings.len() == 1 {
2549 ("this", accessible_path_strings[0].1, format!(" `{}`", accessible_path_strings[0].0))
2551 ("one of these", "items", String::new())
2554 let instead = if let Instead::Yes = instead { " instead" } else { "" };
2555 let mut msg = if let DiagnosticMode::Pattern = mode {
2557 "if you meant to match on {}{}{}, use the full path in the pattern",
2561 format!("consider importing {} {}{}", determiner, kind, instead)
2564 for note in accessible_path_strings.iter().flat_map(|cand| cand.3.as_ref()) {
2568 if let Some(span) = use_placement_span {
2569 let add_use = match mode {
2570 DiagnosticMode::Pattern => {
2571 err.span_suggestions(
2574 accessible_path_strings.into_iter().map(|a| a.0),
2575 Applicability::MaybeIncorrect,
2579 DiagnosticMode::Import => "",
2580 DiagnosticMode::Normal => "use ",
2582 for candidate in &mut accessible_path_strings {
2583 // produce an additional newline to separate the new use statement
2584 // from the directly following item.
2585 let additional_newline = if let FoundUse::Yes = found_use { "" } else { "\n" };
2586 candidate.0 = format!("{}{};\n{}", add_use, &candidate.0, additional_newline);
2589 err.span_suggestions(
2592 accessible_path_strings.into_iter().map(|a| a.0),
2593 Applicability::MaybeIncorrect,
2595 if let [first, .., last] = &path[..] {
2596 let sp = first.ident.span.until(last.ident.span);
2597 if sp.can_be_used_for_suggestions() {
2598 err.span_suggestion_verbose(
2600 &format!("if you import `{}`, refer to it directly", last.ident),
2602 Applicability::Unspecified,
2609 for candidate in accessible_path_strings {
2611 msg.push_str(&candidate.0);
2616 } else if !matches!(mode, DiagnosticMode::Import) {
2617 assert!(!inaccessible_path_strings.is_empty());
2619 let prefix = if let DiagnosticMode::Pattern = mode {
2620 "you might have meant to match on "
2624 if inaccessible_path_strings.len() == 1 {
2625 let (name, descr, def_id, note) = &inaccessible_path_strings[0];
2627 "{}{} `{}`{} exists but is inaccessible",
2631 if let DiagnosticMode::Pattern = mode { ", which" } else { "" }
2634 if let Some(local_def_id) = def_id.and_then(|did| did.as_local()) {
2635 let span = source_span[local_def_id];
2636 let span = session.source_map().guess_head_span(span);
2637 let mut multi_span = MultiSpan::from_span(span);
2638 multi_span.push_span_label(span, "not accessible");
2639 err.span_note(multi_span, &msg);
2643 if let Some(note) = (*note).as_deref() {
2647 let (_, descr_first, _, _) = &inaccessible_path_strings[0];
2648 let descr = if inaccessible_path_strings
2651 .all(|(_, descr, _, _)| descr == descr_first)
2658 if descr.ends_with('s') { format!("{}es", descr) } else { format!("{}s", descr) };
2660 let mut msg = format!("{}these {} exist but are inaccessible", prefix, plural_descr);
2661 let mut has_colon = false;
2663 let mut spans = Vec::new();
2664 for (name, _, def_id, _) in &inaccessible_path_strings {
2665 if let Some(local_def_id) = def_id.and_then(|did| did.as_local()) {
2666 let span = source_span[local_def_id];
2667 let span = session.source_map().guess_head_span(span);
2668 spans.push((name, span));
2679 let mut multi_span = MultiSpan::from_spans(spans.iter().map(|(_, sp)| *sp).collect());
2680 for (name, span) in spans {
2681 multi_span.push_span_label(span, format!("`{}`: not accessible", name));
2684 for note in inaccessible_path_strings.iter().flat_map(|cand| cand.3.as_ref()) {
2688 err.span_note(multi_span, &msg);
2694 struct UsePlacementFinder {
2695 target_module: NodeId,
2696 first_legal_span: Option<Span>,
2697 first_use_span: Option<Span>,
2700 impl UsePlacementFinder {
2701 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, FoundUse) {
2703 UsePlacementFinder { target_module, first_legal_span: None, first_use_span: None };
2704 finder.visit_crate(krate);
2705 if let Some(use_span) = finder.first_use_span {
2706 (Some(use_span), FoundUse::Yes)
2708 (finder.first_legal_span, FoundUse::No)
2713 impl<'tcx> visit::Visitor<'tcx> for UsePlacementFinder {
2714 fn visit_crate(&mut self, c: &Crate) {
2715 if self.target_module == CRATE_NODE_ID {
2716 let inject = c.spans.inject_use_span;
2717 if is_span_suitable_for_use_injection(inject) {
2718 self.first_legal_span = Some(inject);
2720 self.first_use_span = search_for_any_use_in_items(&c.items);
2723 visit::walk_crate(self, c);
2727 fn visit_item(&mut self, item: &'tcx ast::Item) {
2728 if self.target_module == item.id {
2729 if let ItemKind::Mod(_, ModKind::Loaded(items, _inline, mod_spans)) = &item.kind {
2730 let inject = mod_spans.inject_use_span;
2731 if is_span_suitable_for_use_injection(inject) {
2732 self.first_legal_span = Some(inject);
2734 self.first_use_span = search_for_any_use_in_items(items);
2738 visit::walk_item(self, item);
2743 fn search_for_any_use_in_items(items: &[P<ast::Item>]) -> Option<Span> {
2745 if let ItemKind::Use(..) = item.kind {
2746 if is_span_suitable_for_use_injection(item.span) {
2747 return Some(item.span.shrink_to_lo());
2754 fn is_span_suitable_for_use_injection(s: Span) -> bool {
2755 // don't suggest placing a use before the prelude
2756 // import or other generated ones
2760 /// Convert the given number into the corresponding ordinal
2761 pub(crate) fn ordinalize(v: usize) -> String {
2762 let suffix = match ((11..=13).contains(&(v % 100)), v % 10) {
2768 format!("{v}{suffix}")