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_user_facing() {
195 false => "definition",
198 let new_participle = match new_binding.is_import_user_facing() {
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_user_facing(), new_binding.is_import_user_facing()) {
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 can_suggest = |binding: &NameBinding<'_>, import: &self::Import<'_>| {
252 !binding.span.is_dummy()
253 && !matches!(import.kind, ImportKind::MacroUse | ImportKind::MacroExport)
255 let import = match (&new_binding.kind, &old_binding.kind) {
256 // If there are two imports where one or both have attributes then prefer removing the
257 // import without attributes.
258 (Import { import: new, .. }, Import { import: old, .. })
260 (new.has_attributes || old.has_attributes)
261 && can_suggest(old_binding, old)
262 && can_suggest(new_binding, new)
265 if old.has_attributes {
266 Some((new, new_binding.span, true))
268 Some((old, old_binding.span, true))
271 // Otherwise prioritize the new binding.
272 (Import { import, .. }, other) if can_suggest(new_binding, import) => {
273 Some((import, new_binding.span, other.is_import()))
275 (other, Import { import, .. }) if can_suggest(old_binding, import) => {
276 Some((import, old_binding.span, other.is_import()))
281 // Check if the target of the use for both bindings is the same.
282 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
283 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
285 self.extern_prelude.get(&ident).map_or(true, |entry| entry.introduced_by_item);
286 // Only suggest removing an import if both bindings are to the same def, if both spans
287 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
288 // been introduced by an item.
289 let should_remove_import = duplicate
291 && ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
294 Some((import, span, true)) if should_remove_import && import.is_nested() => {
295 self.add_suggestion_for_duplicate_nested_use(&mut err, import, span)
297 Some((import, _, true)) if should_remove_import && !import.is_glob() => {
298 // Simple case - remove the entire import. Due to the above match arm, this can
299 // only be a single use so just remove it entirely.
300 err.tool_only_span_suggestion(
301 import.use_span_with_attributes,
302 "remove unnecessary import",
304 Applicability::MaybeIncorrect,
307 Some((import, span, _)) => {
308 self.add_suggestion_for_rename_of_use(&mut err, name, import, span)
314 self.name_already_seen.insert(name, span);
317 /// This function adds a suggestion to change the binding name of a new import that conflicts
318 /// with an existing import.
320 /// ```text,ignore (diagnostic)
321 /// help: you can use `as` to change the binding name of the import
323 /// LL | use foo::bar as other_bar;
324 /// | ^^^^^^^^^^^^^^^^^^^^^
326 fn add_suggestion_for_rename_of_use(
328 err: &mut Diagnostic,
333 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
334 format!("Other{}", name)
336 format!("other_{}", name)
339 let mut suggestion = None;
341 ImportKind::Single { type_ns_only: true, .. } => {
342 suggestion = Some(format!("self as {}", suggested_name))
344 ImportKind::Single { source, .. } => {
346 source.span.hi().0.checked_sub(binding_span.lo().0).map(|pos| pos as usize)
348 if let Ok(snippet) = self.session.source_map().span_to_snippet(binding_span) {
349 if pos <= snippet.len() {
350 suggestion = Some(format!(
354 if snippet.ends_with(';') { ";" } else { "" }
360 ImportKind::ExternCrate { source, target, .. } => {
361 suggestion = Some(format!(
362 "extern crate {} as {};",
363 source.unwrap_or(target.name),
370 let rename_msg = "you can use `as` to change the binding name of the import";
371 if let Some(suggestion) = suggestion {
376 Applicability::MaybeIncorrect,
379 err.span_label(binding_span, rename_msg);
383 /// This function adds a suggestion to remove an unnecessary binding from an import that is
384 /// nested. In the following example, this function will be invoked to remove the `a` binding
385 /// in the second use statement:
387 /// ```ignore (diagnostic)
388 /// use issue_52891::a;
389 /// use issue_52891::{d, a, e};
392 /// The following suggestion will be added:
394 /// ```ignore (diagnostic)
395 /// use issue_52891::{d, a, e};
396 /// ^-- help: remove unnecessary import
399 /// If the nested use contains only one import then the suggestion will remove the entire
402 /// It is expected that the provided import is nested - this isn't checked by the
403 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
404 /// as characters expected by span manipulations won't be present.
405 fn add_suggestion_for_duplicate_nested_use(
407 err: &mut Diagnostic,
411 assert!(import.is_nested());
412 let message = "remove unnecessary import";
414 // Two examples will be used to illustrate the span manipulations we're doing:
416 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
417 // `a` and `import.use_span` is `issue_52891::{d, a, e};`.
418 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
419 // `a` and `import.use_span` is `issue_52891::{d, e, a};`.
421 let (found_closing_brace, span) =
422 find_span_of_binding_until_next_binding(self.session, binding_span, import.use_span);
424 // If there was a closing brace then identify the span to remove any trailing commas from
426 if found_closing_brace {
427 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
428 err.tool_only_span_suggestion(span, message, "", Applicability::MaybeIncorrect);
430 // Remove the entire line if we cannot extend the span back, this indicates an
431 // `issue_52891::{self}` case.
433 import.use_span_with_attributes,
436 Applicability::MaybeIncorrect,
443 err.span_suggestion(span, message, "", Applicability::MachineApplicable);
446 pub(crate) fn lint_if_path_starts_with_module(
448 finalize: Option<Finalize>,
450 second_binding: Option<&NameBinding<'_>>,
452 let Some(Finalize { node_id, root_span, .. }) = finalize else {
456 let first_name = match path.get(0) {
457 // In the 2018 edition this lint is a hard error, so nothing to do
458 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
462 // We're only interested in `use` paths which should start with
463 // `{{root}}` currently.
464 if first_name != kw::PathRoot {
469 // If this import looks like `crate::...` it's already good
470 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
471 // Otherwise go below to see if it's an extern crate
473 // If the path has length one (and it's `PathRoot` most likely)
474 // then we don't know whether we're gonna be importing a crate or an
475 // item in our crate. Defer this lint to elsewhere
479 // If the first element of our path was actually resolved to an
480 // `ExternCrate` (also used for `crate::...`) then no need to issue a
481 // warning, this looks all good!
482 if let Some(binding) = second_binding {
483 if let NameBindingKind::Import { import, .. } = binding.kind {
484 // Careful: we still want to rewrite paths from renamed extern crates.
485 if let ImportKind::ExternCrate { source: None, .. } = import.kind {
491 let diag = BuiltinLintDiagnostics::AbsPathWithModule(root_span);
492 self.lint_buffer.buffer_lint_with_diagnostic(
493 ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
496 "absolute paths must start with `self`, `super`, \
497 `crate`, or an external crate name in the 2018 edition",
502 pub(crate) fn add_module_candidates(
505 names: &mut Vec<TypoSuggestion>,
506 filter_fn: &impl Fn(Res) -> bool,
507 ctxt: Option<SyntaxContext>,
509 for (key, resolution) in self.resolutions(module).borrow().iter() {
510 if let Some(binding) = resolution.borrow().binding {
511 let res = binding.res();
512 if filter_fn(res) && ctxt.map_or(true, |ctxt| ctxt == key.ident.span.ctxt()) {
513 names.push(TypoSuggestion::typo_from_ident(key.ident, res));
519 /// Combines an error with provided span and emits it.
521 /// This takes the error provided, combines it with the span and any additional spans inside the
522 /// error and emits it.
523 pub(crate) fn report_error(&mut self, span: Span, resolution_error: ResolutionError<'a>) {
524 self.into_struct_error(span, resolution_error).emit();
527 pub(crate) fn into_struct_error(
530 resolution_error: ResolutionError<'a>,
531 ) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
532 match resolution_error {
533 ResolutionError::GenericParamsFromOuterFunction(outer_res, has_generic_params) => {
534 let mut err = struct_span_err!(
538 "can't use generic parameters from outer function",
540 err.span_label(span, "use of generic parameter from outer function");
542 let sm = self.session.source_map();
543 let def_id = match outer_res {
544 Res::SelfTyParam { .. } => {
545 err.span_label(span, "can't use `Self` here");
548 Res::SelfTyAlias { alias_to: def_id, .. } => {
549 if let Some(impl_span) = self.opt_span(def_id) {
551 reduce_impl_span_to_impl_keyword(sm, impl_span),
552 "`Self` type implicitly declared here, by this `impl`",
555 err.span_label(span, "use a type here instead");
558 Res::Def(DefKind::TyParam, def_id) => {
559 if let Some(span) = self.opt_span(def_id) {
560 err.span_label(span, "type parameter from outer function");
564 Res::Def(DefKind::ConstParam, def_id) => {
565 if let Some(span) = self.opt_span(def_id) {
566 err.span_label(span, "const parameter from outer function");
572 "GenericParamsFromOuterFunction should only be used with \
573 Res::SelfTyParam, Res::SelfTyAlias, DefKind::TyParam or \
579 if let HasGenericParams::Yes(span) = has_generic_params {
580 // Try to retrieve the span of the function signature and generate a new
581 // message with a local type or const parameter.
582 let sugg_msg = "try using a local generic parameter instead";
583 let name = self.opt_name(def_id).unwrap_or(sym::T);
584 let (span, snippet) = if span.is_empty() {
585 let snippet = format!("<{}>", name);
588 let span = sm.span_through_char(span, '<').shrink_to_hi();
589 let snippet = format!("{}, ", name);
592 // Suggest the modification to the user
593 err.span_suggestion(span, sugg_msg, snippet, Applicability::MaybeIncorrect);
598 ResolutionError::NameAlreadyUsedInParameterList(name, first_use_span) => {
599 let mut err = struct_span_err!(
603 "the name `{}` is already used for a generic \
604 parameter in this item's generic parameters",
607 err.span_label(span, "already used");
608 err.span_label(first_use_span, format!("first use of `{}`", name));
611 ResolutionError::MethodNotMemberOfTrait(method, trait_, candidate) => {
612 let mut err = struct_span_err!(
616 "method `{}` is not a member of trait `{}`",
620 err.span_label(span, format!("not a member of trait `{}`", trait_));
621 if let Some(candidate) = candidate {
624 "there is an associated function with a similar name",
625 candidate.to_ident_string(),
626 Applicability::MaybeIncorrect,
631 ResolutionError::TypeNotMemberOfTrait(type_, trait_, candidate) => {
632 let mut err = struct_span_err!(
636 "type `{}` is not a member of trait `{}`",
640 err.span_label(span, format!("not a member of trait `{}`", trait_));
641 if let Some(candidate) = candidate {
644 "there is an associated type with a similar name",
645 candidate.to_ident_string(),
646 Applicability::MaybeIncorrect,
651 ResolutionError::ConstNotMemberOfTrait(const_, trait_, candidate) => {
652 let mut err = struct_span_err!(
656 "const `{}` is not a member of trait `{}`",
660 err.span_label(span, format!("not a member of trait `{}`", trait_));
661 if let Some(candidate) = candidate {
664 "there is an associated constant with a similar name",
665 candidate.to_ident_string(),
666 Applicability::MaybeIncorrect,
671 ResolutionError::VariableNotBoundInPattern(binding_error, parent_scope) => {
672 let BindingError { name, target, origin, could_be_path } = binding_error;
674 let target_sp = target.iter().copied().collect::<Vec<_>>();
675 let origin_sp = origin.iter().copied().collect::<Vec<_>>();
677 let msp = MultiSpan::from_spans(target_sp.clone());
678 let mut err = struct_span_err!(
682 "variable `{}` is not bound in all patterns",
685 for sp in target_sp {
686 err.span_label(sp, format!("pattern doesn't bind `{}`", name));
688 for sp in origin_sp {
689 err.span_label(sp, "variable not in all patterns");
692 let import_suggestions = self.lookup_import_candidates(
693 Ident::with_dummy_span(name),
696 &|res: Res| match res {
698 DefKind::Ctor(CtorOf::Variant, CtorKind::Const)
699 | DefKind::Ctor(CtorOf::Struct, CtorKind::Const)
701 | DefKind::AssocConst,
708 if import_suggestions.is_empty() {
709 let help_msg = format!(
710 "if you meant to match on a variant or a `const` item, consider \
711 making the path in the pattern qualified: `path::to::ModOrType::{}`",
714 err.span_help(span, &help_msg);
724 DiagnosticMode::Pattern,
730 ResolutionError::VariableBoundWithDifferentMode(variable_name, first_binding_span) => {
731 let mut err = struct_span_err!(
735 "variable `{}` is bound inconsistently across alternatives separated by `|`",
738 err.span_label(span, "bound in different ways");
739 err.span_label(first_binding_span, "first binding");
742 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
743 let mut err = struct_span_err!(
747 "identifier `{}` is bound more than once in this parameter list",
750 err.span_label(span, "used as parameter more than once");
753 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
754 let mut err = struct_span_err!(
758 "identifier `{}` is bound more than once in the same pattern",
761 err.span_label(span, "used in a pattern more than once");
764 ResolutionError::UndeclaredLabel { name, suggestion } => {
765 let mut err = struct_span_err!(
769 "use of undeclared label `{}`",
773 err.span_label(span, format!("undeclared label `{}`", name));
776 // A reachable label with a similar name exists.
777 Some((ident, true)) => {
778 err.span_label(ident.span, "a label with a similar name is reachable");
781 "try using similarly named label",
783 Applicability::MaybeIncorrect,
786 // An unreachable label with a similar name exists.
787 Some((ident, false)) => {
790 "a label with a similar name exists but is unreachable",
793 // No similarly-named labels exist.
799 ResolutionError::SelfImportsOnlyAllowedWithin { root, span_with_rename } => {
800 let mut err = struct_span_err!(
805 "`self` imports are only allowed within a { } list"
808 // None of the suggestions below would help with a case like `use self`.
810 // use foo::bar::self -> foo::bar
811 // use foo::bar::self as abc -> foo::bar as abc
814 "consider importing the module directly",
816 Applicability::MachineApplicable,
819 // use foo::bar::self -> foo::bar::{self}
820 // use foo::bar::self as abc -> foo::bar::{self as abc}
822 (span_with_rename.shrink_to_lo(), "{".to_string()),
823 (span_with_rename.shrink_to_hi(), "}".to_string()),
825 err.multipart_suggestion(
826 "alternatively, use the multi-path `use` syntax to import `self`",
828 Applicability::MachineApplicable,
833 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
834 let mut err = struct_span_err!(
838 "`self` import can only appear once in an import list"
840 err.span_label(span, "can only appear once in an import list");
843 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
844 let mut err = struct_span_err!(
848 "`self` import can only appear in an import list with \
851 err.span_label(span, "can only appear in an import list with a non-empty prefix");
854 ResolutionError::FailedToResolve { label, suggestion } => {
856 struct_span_err!(self.session, span, E0433, "failed to resolve: {}", &label);
857 err.span_label(span, label);
859 if let Some((suggestions, msg, applicability)) = suggestion {
860 if suggestions.is_empty() {
864 err.multipart_suggestion(&msg, suggestions, applicability);
869 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
870 let mut err = struct_span_err!(
875 "can't capture dynamic environment in a fn item"
877 err.help("use the `|| { ... }` closure form instead");
880 ResolutionError::AttemptToUseNonConstantValueInConstant(ident, sugg, current) => {
881 let mut err = struct_span_err!(
885 "attempt to use a non-constant value in a constant"
888 // ^^^ given this Span
889 // ------- get this Span to have an applicable suggestion
892 // only do this if the const and usage of the non-constant value are on the same line
893 // the further the two are apart, the higher the chance of the suggestion being wrong
898 .span_extend_to_prev_str(ident.span, current, true, false);
901 Some(sp) if !self.session.source_map().is_multiline(sp) => {
902 let sp = sp.with_lo(BytePos(sp.lo().0 - (current.len() as u32)));
905 &format!("consider using `{}` instead of `{}`", sugg, current),
906 format!("{} {}", sugg, ident),
907 Applicability::MaybeIncorrect,
909 err.span_label(span, "non-constant value");
912 err.span_label(ident.span, &format!("this would need to be a `{}`", sugg));
918 ResolutionError::BindingShadowsSomethingUnacceptable {
924 shadowed_binding_span,
926 let shadowed_binding_descr = shadowed_binding.descr();
927 let mut err = struct_span_err!(
931 "{}s cannot shadow {}s",
932 shadowing_binding.descr(),
933 shadowed_binding_descr,
937 format!("cannot be named the same as {} {}", article, shadowed_binding_descr),
939 match (shadowing_binding, shadowed_binding) {
941 PatternSource::Match,
942 Res::Def(DefKind::Ctor(CtorOf::Variant | CtorOf::Struct, CtorKind::Fn), _),
946 "try specify the pattern arguments",
947 format!("{}(..)", name),
948 Applicability::Unspecified,
954 format!("the {} `{}` is {} here", shadowed_binding_descr, name, participle);
955 err.span_label(shadowed_binding_span, msg);
958 ResolutionError::ForwardDeclaredGenericParam => {
959 let mut err = struct_span_err!(
963 "generic parameters with a default cannot use \
964 forward declared identifiers"
966 err.span_label(span, "defaulted generic parameters cannot be forward declared");
969 ResolutionError::ParamInTyOfConstParam(name) => {
970 let mut err = struct_span_err!(
974 "the type of const parameters must not depend on other generic parameters"
978 format!("the type must not depend on the parameter `{}`", name),
982 ResolutionError::ParamInNonTrivialAnonConst { name, is_type } => {
983 let mut err = self.session.struct_span_err(
985 "generic parameters may not be used in const operations",
987 err.span_label(span, &format!("cannot perform const operation using `{}`", name));
990 err.note("type parameters may not be used in const expressions");
993 "const parameters may only be used as standalone arguments, i.e. `{}`",
998 if self.session.is_nightly_build() {
1000 "use `#![feature(generic_const_exprs)]` to allow generic const expressions",
1006 ResolutionError::SelfInGenericParamDefault => {
1007 let mut err = struct_span_err!(
1011 "generic parameters cannot use `Self` in their defaults"
1013 err.span_label(span, "`Self` in generic parameter default");
1016 ResolutionError::UnreachableLabel { name, definition_span, suggestion } => {
1017 let mut err = struct_span_err!(
1021 "use of unreachable label `{}`",
1025 err.span_label(definition_span, "unreachable label defined here");
1026 err.span_label(span, format!("unreachable label `{}`", name));
1028 "labels are unreachable through functions, closures, async blocks and modules",
1032 // A reachable label with a similar name exists.
1033 Some((ident, true)) => {
1034 err.span_label(ident.span, "a label with a similar name is reachable");
1035 err.span_suggestion(
1037 "try using similarly named label",
1039 Applicability::MaybeIncorrect,
1042 // An unreachable label with a similar name exists.
1043 Some((ident, false)) => {
1046 "a label with a similar name exists but is also unreachable",
1049 // No similarly-named labels exist.
1055 ResolutionError::TraitImplMismatch {
1062 let mut err = self.session.struct_span_err_with_code(
1065 "item `{}` is an associated {}, which doesn't match its trait `{}`",
1066 name, kind, trait_path,
1070 err.span_label(span, "does not match trait");
1071 err.span_label(trait_item_span, "item in trait");
1074 ResolutionError::TraitImplDuplicate { name, trait_item_span, old_span } => {
1075 let mut err = struct_span_err!(
1079 "duplicate definitions with name `{}`:",
1082 err.span_label(old_span, "previous definition here");
1083 err.span_label(trait_item_span, "item in trait");
1084 err.span_label(span, "duplicate definition");
1087 ResolutionError::InvalidAsmSym => {
1088 let mut err = self.session.struct_span_err(span, "invalid `sym` operand");
1089 err.span_label(span, "is a local variable");
1090 err.help("`sym` operands must refer to either a function or a static");
1096 pub(crate) fn report_vis_error(
1098 vis_resolution_error: VisResolutionError<'_>,
1099 ) -> ErrorGuaranteed {
1100 match vis_resolution_error {
1101 VisResolutionError::Relative2018(span, path) => {
1102 let mut err = self.session.struct_span_err(
1104 "relative paths are not supported in visibilities in 2018 edition or later",
1106 err.span_suggestion(
1109 format!("crate::{}", pprust::path_to_string(&path)),
1110 Applicability::MaybeIncorrect,
1114 VisResolutionError::AncestorOnly(span) => struct_span_err!(
1118 "visibilities can only be restricted to ancestor modules"
1120 VisResolutionError::FailedToResolve(span, label, suggestion) => {
1121 self.into_struct_error(span, ResolutionError::FailedToResolve { label, suggestion })
1123 VisResolutionError::ExpectedFound(span, path_str, res) => {
1124 let mut err = struct_span_err!(
1128 "expected module, found {} `{}`",
1132 err.span_label(span, "not a module");
1135 VisResolutionError::Indeterminate(span) => struct_span_err!(
1139 "cannot determine resolution for the visibility"
1141 VisResolutionError::ModuleOnly(span) => {
1142 self.session.struct_span_err(span, "visibility must resolve to a module")
1148 /// Lookup typo candidate in scope for a macro or import.
1149 fn early_lookup_typo_candidate(
1151 scope_set: ScopeSet<'a>,
1152 parent_scope: &ParentScope<'a>,
1154 filter_fn: &impl Fn(Res) -> bool,
1155 ) -> Option<TypoSuggestion> {
1156 let mut suggestions = Vec::new();
1157 let ctxt = ident.span.ctxt();
1158 self.visit_scopes(scope_set, parent_scope, ctxt, |this, scope, use_prelude, _| {
1160 Scope::DeriveHelpers(expn_id) => {
1161 let res = Res::NonMacroAttr(NonMacroAttrKind::DeriveHelper);
1168 .map(|ident| TypoSuggestion::typo_from_ident(*ident, res)),
1172 Scope::DeriveHelpersCompat => {
1173 let res = Res::NonMacroAttr(NonMacroAttrKind::DeriveHelperCompat);
1175 for derive in parent_scope.derives {
1176 let parent_scope = &ParentScope { derives: &[], ..*parent_scope };
1177 if let Ok((Some(ext), _)) = this.resolve_macro_path(
1179 Some(MacroKind::Derive),
1187 .map(|name| TypoSuggestion::typo_from_name(*name, res)),
1193 Scope::MacroRules(macro_rules_scope) => {
1194 if let MacroRulesScope::Binding(macro_rules_binding) = macro_rules_scope.get() {
1195 let res = macro_rules_binding.binding.res();
1197 suggestions.push(TypoSuggestion::typo_from_ident(
1198 macro_rules_binding.ident,
1204 Scope::CrateRoot => {
1205 let root_ident = Ident::new(kw::PathRoot, ident.span);
1206 let root_module = this.resolve_crate_root(root_ident);
1207 this.add_module_candidates(root_module, &mut suggestions, filter_fn, None);
1209 Scope::Module(module) => {
1210 this.add_module_candidates(module, &mut suggestions, filter_fn, None);
1212 Scope::MacroUsePrelude => {
1213 suggestions.extend(this.macro_use_prelude.iter().filter_map(
1215 let res = binding.res();
1216 filter_fn(res).then_some(TypoSuggestion::typo_from_name(*name, res))
1220 Scope::BuiltinAttrs => {
1221 let res = Res::NonMacroAttr(NonMacroAttrKind::Builtin(kw::Empty));
1226 .map(|attr| TypoSuggestion::typo_from_name(attr.name, res)),
1230 Scope::ExternPrelude => {
1231 suggestions.extend(this.extern_prelude.iter().filter_map(|(ident, _)| {
1232 let res = Res::Def(DefKind::Mod, CRATE_DEF_ID.to_def_id());
1233 filter_fn(res).then_some(TypoSuggestion::typo_from_ident(*ident, res))
1236 Scope::ToolPrelude => {
1237 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
1239 this.registered_tools
1241 .map(|ident| TypoSuggestion::typo_from_ident(*ident, res)),
1244 Scope::StdLibPrelude => {
1245 if let Some(prelude) = this.prelude {
1246 let mut tmp_suggestions = Vec::new();
1247 this.add_module_candidates(prelude, &mut tmp_suggestions, filter_fn, None);
1251 .filter(|s| use_prelude || this.is_builtin_macro(s.res)),
1255 Scope::BuiltinTypes => {
1256 suggestions.extend(PrimTy::ALL.iter().filter_map(|prim_ty| {
1257 let res = Res::PrimTy(*prim_ty);
1259 .then_some(TypoSuggestion::typo_from_name(prim_ty.name(), res))
1267 // Make sure error reporting is deterministic.
1268 suggestions.sort_by(|a, b| a.candidate.as_str().partial_cmp(b.candidate.as_str()).unwrap());
1270 match find_best_match_for_name(
1271 &suggestions.iter().map(|suggestion| suggestion.candidate).collect::<Vec<Symbol>>(),
1275 Some(found) if found != ident.name => {
1276 suggestions.into_iter().find(|suggestion| suggestion.candidate == found)
1282 fn lookup_import_candidates_from_module<FilterFn>(
1284 lookup_ident: Ident,
1285 namespace: Namespace,
1286 parent_scope: &ParentScope<'a>,
1287 start_module: Module<'a>,
1289 filter_fn: FilterFn,
1290 ) -> Vec<ImportSuggestion>
1292 FilterFn: Fn(Res) -> bool,
1294 let mut candidates = Vec::new();
1295 let mut seen_modules = FxHashSet::default();
1296 let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), true)];
1297 let mut worklist_via_import = vec![];
1299 while let Some((in_module, path_segments, accessible)) = match worklist.pop() {
1300 None => worklist_via_import.pop(),
1303 let in_module_is_extern = !in_module.def_id().is_local();
1304 // We have to visit module children in deterministic order to avoid
1305 // instabilities in reported imports (#43552).
1306 in_module.for_each_child(self, |this, ident, ns, name_binding| {
1307 // avoid non-importable candidates
1308 if !name_binding.is_importable() {
1312 let child_accessible =
1313 accessible && this.is_accessible_from(name_binding.vis, parent_scope.module);
1315 // do not venture inside inaccessible items of other crates
1316 if in_module_is_extern && !child_accessible {
1320 let via_import = name_binding.is_import() && !name_binding.is_extern_crate();
1322 // There is an assumption elsewhere that paths of variants are in the enum's
1323 // declaration and not imported. With this assumption, the variant component is
1324 // chopped and the rest of the path is assumed to be the enum's own path. For
1325 // errors where a variant is used as the type instead of the enum, this causes
1326 // funny looking invalid suggestions, i.e `foo` instead of `foo::MyEnum`.
1327 if via_import && name_binding.is_possibly_imported_variant() {
1331 // #90113: Do not count an inaccessible reexported item as a candidate.
1332 if let NameBindingKind::Import { binding, .. } = name_binding.kind {
1333 if this.is_accessible_from(binding.vis, parent_scope.module)
1334 && !this.is_accessible_from(name_binding.vis, parent_scope.module)
1340 // collect results based on the filter function
1341 // avoid suggesting anything from the same module in which we are resolving
1342 // avoid suggesting anything with a hygienic name
1343 if ident.name == lookup_ident.name
1345 && !ptr::eq(in_module, parent_scope.module)
1346 && !ident.span.normalize_to_macros_2_0().from_expansion()
1348 let res = name_binding.res();
1351 let mut segms = path_segments.clone();
1352 if lookup_ident.span.rust_2018() {
1353 // crate-local absolute paths start with `crate::` in edition 2018
1354 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
1355 segms.insert(0, ast::PathSegment::from_ident(crate_name));
1358 segms.push(ast::PathSegment::from_ident(ident));
1359 let path = Path { span: name_binding.span, segments: segms, tokens: None };
1360 let did = match res {
1361 Res::Def(DefKind::Ctor(..), did) => this.opt_parent(did),
1362 _ => res.opt_def_id(),
1365 if child_accessible {
1366 // Remove invisible match if exists
1367 if let Some(idx) = candidates
1369 .position(|v: &ImportSuggestion| v.did == did && !v.accessible)
1371 candidates.remove(idx);
1375 if candidates.iter().all(|v: &ImportSuggestion| v.did != did) {
1376 // See if we're recommending TryFrom, TryInto, or FromIterator and add
1377 // a note about editions
1378 let note = if let Some(did) = did {
1379 let requires_note = !did.is_local()
1380 && this.cstore().item_attrs_untracked(did, this.session).any(
1382 if attr.has_name(sym::rustc_diagnostic_item) {
1383 [sym::TryInto, sym::TryFrom, sym::FromIterator]
1385 .contains(&attr.value_str())
1392 requires_note.then(|| {
1394 "'{}' is included in the prelude starting in Edition 2021",
1395 path_names_to_string(&path)
1402 candidates.push(ImportSuggestion {
1406 accessible: child_accessible,
1413 // collect submodules to explore
1414 if let Some(module) = name_binding.module() {
1416 let mut path_segments = path_segments.clone();
1417 path_segments.push(ast::PathSegment::from_ident(ident));
1419 let is_extern_crate_that_also_appears_in_prelude =
1420 name_binding.is_extern_crate() && lookup_ident.span.rust_2018();
1422 if !is_extern_crate_that_also_appears_in_prelude {
1423 // add the module to the lookup
1424 if seen_modules.insert(module.def_id()) {
1425 if via_import { &mut worklist_via_import } else { &mut worklist }
1426 .push((module, path_segments, child_accessible));
1433 // If only some candidates are accessible, take just them
1434 if !candidates.iter().all(|v: &ImportSuggestion| !v.accessible) {
1435 candidates.retain(|x| x.accessible)
1441 /// When name resolution fails, this method can be used to look up candidate
1442 /// entities with the expected name. It allows filtering them using the
1443 /// supplied predicate (which should be used to only accept the types of
1444 /// definitions expected, e.g., traits). The lookup spans across all crates.
1446 /// N.B., the method does not look into imports, but this is not a problem,
1447 /// since we report the definitions (thus, the de-aliased imports).
1448 pub(crate) fn lookup_import_candidates<FilterFn>(
1450 lookup_ident: Ident,
1451 namespace: Namespace,
1452 parent_scope: &ParentScope<'a>,
1453 filter_fn: FilterFn,
1454 ) -> Vec<ImportSuggestion>
1456 FilterFn: Fn(Res) -> bool,
1458 let mut suggestions = self.lookup_import_candidates_from_module(
1463 Ident::with_dummy_span(kw::Crate),
1467 if lookup_ident.span.rust_2018() {
1468 let extern_prelude_names = self.extern_prelude.clone();
1469 for (ident, _) in extern_prelude_names.into_iter() {
1470 if ident.span.from_expansion() {
1471 // Idents are adjusted to the root context before being
1472 // resolved in the extern prelude, so reporting this to the
1473 // user is no help. This skips the injected
1474 // `extern crate std` in the 2018 edition, which would
1475 // otherwise cause duplicate suggestions.
1478 if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name) {
1479 let crate_root = self.expect_module(crate_id.as_def_id());
1480 suggestions.extend(self.lookup_import_candidates_from_module(
1495 pub(crate) fn unresolved_macro_suggestions(
1497 err: &mut Diagnostic,
1498 macro_kind: MacroKind,
1499 parent_scope: &ParentScope<'a>,
1502 let is_expected = &|res: Res| res.macro_kind() == Some(macro_kind);
1503 let suggestion = self.early_lookup_typo_candidate(
1504 ScopeSet::Macro(macro_kind),
1509 self.add_typo_suggestion(err, suggestion, ident.span);
1511 let import_suggestions =
1512 self.lookup_import_candidates(ident, Namespace::MacroNS, parent_scope, is_expected);
1518 &import_suggestions,
1521 DiagnosticMode::Normal,
1525 if macro_kind == MacroKind::Derive && (ident.name == sym::Send || ident.name == sym::Sync) {
1526 let msg = format!("unsafe traits like `{}` should be implemented explicitly", ident);
1527 err.span_note(ident.span, &msg);
1530 if self.macro_names.contains(&ident.normalize_to_macros_2_0()) {
1531 err.help("have you added the `#[macro_use]` on the module/import?");
1534 if ident.name == kw::Default
1535 && let ModuleKind::Def(DefKind::Enum, def_id, _) = parent_scope.module.kind
1536 && let Some(span) = self.opt_span(def_id)
1538 let source_map = self.session.source_map();
1539 let head_span = source_map.guess_head_span(span);
1540 if let Ok(head) = source_map.span_to_snippet(head_span) {
1541 err.span_suggestion(head_span, "consider adding a derive", format!("#[derive(Default)]\n{head}"), Applicability::MaybeIncorrect);
1545 "consider adding `#[derive(Default)]` to this enum",
1549 for ns in [Namespace::MacroNS, Namespace::TypeNS, Namespace::ValueNS] {
1550 if let Ok(binding) = self.early_resolve_ident_in_lexical_scope(
1552 ScopeSet::All(ns, false),
1558 let desc = match binding.res() {
1559 Res::Def(DefKind::Macro(MacroKind::Bang), _) => {
1560 "a function-like macro".to_string()
1562 Res::Def(DefKind::Macro(MacroKind::Attr), _) | Res::NonMacroAttr(..) => {
1563 format!("an attribute: `#[{}]`", ident)
1565 Res::Def(DefKind::Macro(MacroKind::Derive), _) => {
1566 format!("a derive macro: `#[derive({})]`", ident)
1569 // Don't confuse the user with tool modules.
1572 Res::Def(DefKind::Trait, _) if macro_kind == MacroKind::Derive => {
1573 "only a trait, without a derive macro".to_string()
1579 macro_kind.article(),
1580 macro_kind.descr_expected(),
1583 if let crate::NameBindingKind::Import { import, .. } = binding.kind {
1584 if !import.span.is_dummy() {
1587 &format!("`{}` is imported here, but it is {}", ident, desc),
1589 // Silence the 'unused import' warning we might get,
1590 // since this diagnostic already covers that import.
1591 self.record_use(ident, binding, false);
1595 err.note(&format!("`{}` is in scope, but it is {}", ident, desc));
1601 pub(crate) fn add_typo_suggestion(
1603 err: &mut Diagnostic,
1604 suggestion: Option<TypoSuggestion>,
1607 let suggestion = match suggestion {
1608 None => return false,
1609 // We shouldn't suggest underscore.
1610 Some(suggestion) if suggestion.candidate == kw::Underscore => return false,
1611 Some(suggestion) => suggestion,
1613 let def_span = suggestion.res.opt_def_id().and_then(|def_id| match def_id.krate {
1614 LOCAL_CRATE => self.opt_span(def_id),
1615 _ => Some(self.cstore().get_span_untracked(def_id, self.session)),
1617 if let Some(def_span) = def_span {
1618 if span.overlaps(def_span) {
1619 // Don't suggest typo suggestion for itself like in the following:
1620 // error[E0423]: expected function, tuple struct or tuple variant, found struct `X`
1621 // --> $DIR/issue-64792-bad-unicode-ctor.rs:3:14
1624 // | ----------- `X` defined here
1626 // LL | const Y: X = X("ö");
1627 // | -------------^^^^^^- similarly named constant `Y` defined here
1629 // help: use struct literal syntax instead
1631 // LL | const Y: X = X {};
1633 // help: a constant with a similar name exists
1635 // LL | const Y: X = Y("ö");
1639 let prefix = match suggestion.target {
1640 SuggestionTarget::SimilarlyNamed => "similarly named ",
1641 SuggestionTarget::SingleItem => "",
1645 self.session.source_map().guess_head_span(def_span),
1647 "{}{} `{}` defined here",
1649 suggestion.res.descr(),
1650 suggestion.candidate,
1654 let msg = match suggestion.target {
1655 SuggestionTarget::SimilarlyNamed => format!(
1656 "{} {} with a similar name exists",
1657 suggestion.res.article(),
1658 suggestion.res.descr()
1660 SuggestionTarget::SingleItem => {
1661 format!("maybe you meant this {}", suggestion.res.descr())
1664 err.span_suggestion(span, &msg, suggestion.candidate, Applicability::MaybeIncorrect);
1668 fn binding_description(&self, b: &NameBinding<'_>, ident: Ident, from_prelude: bool) -> String {
1670 if b.span.is_dummy() || !self.session.source_map().is_span_accessible(b.span) {
1671 // These already contain the "built-in" prefix or look bad with it.
1673 !matches!(b.res(), Res::NonMacroAttr(..) | Res::PrimTy(..) | Res::ToolMod);
1674 let (built_in, from) = if from_prelude {
1675 ("", " from prelude")
1676 } else if b.is_extern_crate()
1678 && self.session.opts.externs.get(ident.as_str()).is_some()
1680 ("", " passed with `--extern`")
1681 } else if add_built_in {
1687 let a = if built_in.is_empty() { res.article() } else { "a" };
1688 format!("{a}{built_in} {thing}{from}", thing = res.descr())
1690 let introduced = if b.is_import_user_facing() { "imported" } else { "defined" };
1691 format!("the {thing} {introduced} here", thing = res.descr())
1695 fn report_ambiguity_error(&self, ambiguity_error: &AmbiguityError<'_>) {
1696 let AmbiguityError { kind, ident, b1, b2, misc1, misc2 } = *ambiguity_error;
1697 let (b1, b2, misc1, misc2, swapped) = if b2.span.is_dummy() && !b1.span.is_dummy() {
1698 // We have to print the span-less alternative first, otherwise formatting looks bad.
1699 (b2, b1, misc2, misc1, true)
1701 (b1, b2, misc1, misc2, false)
1704 let mut err = struct_span_err!(self.session, ident.span, E0659, "`{ident}` is ambiguous");
1705 err.span_label(ident.span, "ambiguous name");
1706 err.note(&format!("ambiguous because of {}", kind.descr()));
1708 let mut could_refer_to = |b: &NameBinding<'_>, misc: AmbiguityErrorMisc, also: &str| {
1709 let what = self.binding_description(b, ident, misc == AmbiguityErrorMisc::FromPrelude);
1710 let note_msg = format!("`{ident}` could{also} refer to {what}");
1712 let thing = b.res().descr();
1713 let mut help_msgs = Vec::new();
1714 if b.is_glob_import()
1715 && (kind == AmbiguityKind::GlobVsGlob
1716 || kind == AmbiguityKind::GlobVsExpanded
1717 || kind == AmbiguityKind::GlobVsOuter && swapped != also.is_empty())
1719 help_msgs.push(format!(
1720 "consider adding an explicit import of `{ident}` to disambiguate"
1723 if b.is_extern_crate() && ident.span.rust_2018() {
1724 help_msgs.push(format!("use `::{ident}` to refer to this {thing} unambiguously"))
1726 if misc == AmbiguityErrorMisc::SuggestCrate {
1728 .push(format!("use `crate::{ident}` to refer to this {thing} unambiguously"))
1729 } else if misc == AmbiguityErrorMisc::SuggestSelf {
1731 .push(format!("use `self::{ident}` to refer to this {thing} unambiguously"))
1734 err.span_note(b.span, ¬e_msg);
1735 for (i, help_msg) in help_msgs.iter().enumerate() {
1736 let or = if i == 0 { "" } else { "or " };
1737 err.help(&format!("{}{}", or, help_msg));
1741 could_refer_to(b1, misc1, "");
1742 could_refer_to(b2, misc2, " also");
1746 /// If the binding refers to a tuple struct constructor with fields,
1747 /// returns the span of its fields.
1748 fn ctor_fields_span(&self, binding: &NameBinding<'_>) -> Option<Span> {
1749 if let NameBindingKind::Res(Res::Def(
1750 DefKind::Ctor(CtorOf::Struct, CtorKind::Fn),
1754 let def_id = self.parent(ctor_def_id);
1755 let fields = self.field_names.get(&def_id)?;
1756 return fields.iter().map(|name| name.span).reduce(Span::to); // None for `struct Foo()`
1761 fn report_privacy_error(&self, privacy_error: &PrivacyError<'_>) {
1762 let PrivacyError { ident, binding, .. } = *privacy_error;
1764 let res = binding.res();
1765 let ctor_fields_span = self.ctor_fields_span(binding);
1766 let plain_descr = res.descr().to_string();
1767 let nonimport_descr =
1768 if ctor_fields_span.is_some() { plain_descr + " constructor" } else { plain_descr };
1769 let import_descr = nonimport_descr.clone() + " import";
1771 |b: &NameBinding<'_>| if b.is_import() { &import_descr } else { &nonimport_descr };
1773 // Print the primary message.
1774 let descr = get_descr(binding);
1776 struct_span_err!(self.session, ident.span, E0603, "{} `{}` is private", descr, ident);
1777 err.span_label(ident.span, &format!("private {}", descr));
1778 if let Some(span) = ctor_fields_span {
1779 err.span_label(span, "a constructor is private if any of the fields is private");
1782 // Print the whole import chain to make it easier to see what happens.
1783 let first_binding = binding;
1784 let mut next_binding = Some(binding);
1785 let mut next_ident = ident;
1786 while let Some(binding) = next_binding {
1787 let name = next_ident;
1788 next_binding = match binding.kind {
1789 _ if res == Res::Err => None,
1790 NameBindingKind::Import { binding, import, .. } => match import.kind {
1791 _ if binding.span.is_dummy() => None,
1792 ImportKind::Single { source, .. } => {
1793 next_ident = source;
1796 ImportKind::Glob { .. } | ImportKind::MacroUse | ImportKind::MacroExport => {
1799 ImportKind::ExternCrate { .. } => None,
1804 let first = ptr::eq(binding, first_binding);
1806 "{and_refers_to}the {item} `{name}`{which} is defined here{dots}",
1807 and_refers_to = if first { "" } else { "...and refers to " },
1808 item = get_descr(binding),
1809 which = if first { "" } else { " which" },
1810 dots = if next_binding.is_some() { "..." } else { "" },
1812 let def_span = self.session.source_map().guess_head_span(binding.span);
1813 let mut note_span = MultiSpan::from_span(def_span);
1814 if !first && binding.vis.is_public() {
1815 note_span.push_span_label(def_span, "consider importing it directly");
1817 err.span_note(note_span, &msg);
1823 pub(crate) fn find_similarly_named_module_or_crate(
1826 current_module: &Module<'a>,
1827 ) -> Option<Symbol> {
1828 let mut candidates = self
1831 .map(|(ident, _)| ident.name)
1835 .filter(|(_, module)| {
1836 current_module.is_ancestor_of(module) && !ptr::eq(current_module, *module)
1838 .flat_map(|(_, module)| module.kind.name()),
1840 .filter(|c| !c.to_string().is_empty())
1841 .collect::<Vec<_>>();
1844 match find_best_match_for_name(&candidates, ident, None) {
1845 Some(sugg) if sugg == ident => None,
1850 pub(crate) fn report_path_resolution_error(
1853 opt_ns: Option<Namespace>, // `None` indicates a module path in import
1854 parent_scope: &ParentScope<'a>,
1855 ribs: Option<&PerNS<Vec<Rib<'a>>>>,
1856 ignore_binding: Option<&'a NameBinding<'a>>,
1857 module: Option<ModuleOrUniformRoot<'a>>,
1860 ) -> (String, Option<Suggestion>) {
1861 let is_last = i == path.len() - 1;
1862 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
1863 let module_res = match module {
1864 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
1867 if module_res == self.graph_root.res() {
1868 let is_mod = |res| matches!(res, Res::Def(DefKind::Mod, _));
1869 let mut candidates = self.lookup_import_candidates(ident, TypeNS, parent_scope, is_mod);
1871 .sort_by_cached_key(|c| (c.path.segments.len(), pprust::path_to_string(&c.path)));
1872 if let Some(candidate) = candidates.get(0) {
1874 String::from("unresolved import"),
1876 vec![(ident.span, pprust::path_to_string(&candidate.path))],
1877 String::from("a similar path exists"),
1878 Applicability::MaybeIncorrect,
1881 } else if self.session.edition() == Edition::Edition2015 {
1883 format!("maybe a missing crate `{ident}`?"),
1887 "consider adding `extern crate {ident}` to use the `{ident}` crate"
1889 Applicability::MaybeIncorrect,
1893 (format!("could not find `{ident}` in the crate root"), None)
1896 let parent = path[i - 1].ident.name;
1897 let parent = match parent {
1898 // ::foo is mounted at the crate root for 2015, and is the extern
1899 // prelude for 2018+
1900 kw::PathRoot if self.session.edition() > Edition::Edition2015 => {
1901 "the list of imported crates".to_owned()
1903 kw::PathRoot | kw::Crate => "the crate root".to_owned(),
1904 _ => format!("`{parent}`"),
1907 let mut msg = format!("could not find `{}` in {}", ident, parent);
1908 if ns == TypeNS || ns == ValueNS {
1909 let ns_to_try = if ns == TypeNS { ValueNS } else { TypeNS };
1910 let binding = if let Some(module) = module {
1911 self.resolve_ident_in_module(
1919 } else if let Some(ribs) = ribs
1920 && let Some(TypeNS | ValueNS) = opt_ns
1922 match self.resolve_ident_in_lexical_scope(
1930 // we found a locally-imported or available item/module
1931 Some(LexicalScopeBinding::Item(binding)) => Some(binding),
1935 let scopes = ScopeSet::All(ns_to_try, opt_ns.is_none());
1936 self.early_resolve_ident_in_lexical_scope(
1945 if let Some(binding) = binding {
1946 let mut found = |what| {
1948 "expected {}, found {} `{}` in {}",
1955 if binding.module().is_some() {
1958 match binding.res() {
1959 Res::Def(kind, id) => found(kind.descr(id)),
1960 _ => found(ns_to_try.descr()),
1966 } else if ident.name == kw::SelfUpper {
1967 ("`Self` is only available in impls, traits, and type definitions".to_string(), None)
1968 } else if ident.name.as_str().chars().next().map_or(false, |c| c.is_ascii_uppercase()) {
1969 // Check whether the name refers to an item in the value namespace.
1970 let binding = if let Some(ribs) = ribs {
1971 self.resolve_ident_in_lexical_scope(
1982 let match_span = match binding {
1983 // Name matches a local variable. For example:
1986 // let Foo: &str = "";
1987 // println!("{}", Foo::Bar); // Name refers to local
1988 // // variable `Foo`.
1991 Some(LexicalScopeBinding::Res(Res::Local(id))) => {
1992 Some(*self.pat_span_map.get(&id).unwrap())
1994 // Name matches item from a local name binding
1995 // created by `use` declaration. For example:
1997 // pub Foo: &str = "";
2001 // println!("{}", Foo::Bar); // Name refers to local
2002 // // binding `Foo`.
2005 Some(LexicalScopeBinding::Item(name_binding)) => Some(name_binding.span),
2008 let suggestion = if let Some(span) = match_span {
2010 vec![(span, String::from(""))],
2011 format!("`{}` is defined here, but is not a type", ident),
2012 Applicability::MaybeIncorrect,
2018 (format!("use of undeclared type `{}`", ident), suggestion)
2020 let suggestion = if ident.name == sym::alloc {
2023 String::from("add `extern crate alloc` to use the `alloc` crate"),
2024 Applicability::MaybeIncorrect,
2027 self.find_similarly_named_module_or_crate(ident.name, &parent_scope.module).map(
2030 vec![(ident.span, sugg.to_string())],
2031 String::from("there is a crate or module with a similar name"),
2032 Applicability::MaybeIncorrect,
2037 (format!("use of undeclared crate or module `{}`", ident), suggestion)
2042 impl<'a, 'b> ImportResolver<'a, 'b> {
2043 /// Adds suggestions for a path that cannot be resolved.
2044 pub(crate) fn make_path_suggestion(
2047 mut path: Vec<Segment>,
2048 parent_scope: &ParentScope<'b>,
2049 ) -> Option<(Vec<Segment>, Option<String>)> {
2050 debug!("make_path_suggestion: span={:?} path={:?}", span, path);
2052 match (path.get(0), path.get(1)) {
2053 // `{{root}}::ident::...` on both editions.
2054 // On 2015 `{{root}}` is usually added implicitly.
2055 (Some(fst), Some(snd))
2056 if fst.ident.name == kw::PathRoot && !snd.ident.is_path_segment_keyword() => {}
2057 // `ident::...` on 2018.
2059 if fst.ident.span.rust_2018() && !fst.ident.is_path_segment_keyword() =>
2061 // Insert a placeholder that's later replaced by `self`/`super`/etc.
2062 path.insert(0, Segment::from_ident(Ident::empty()));
2067 self.make_missing_self_suggestion(path.clone(), parent_scope)
2068 .or_else(|| self.make_missing_crate_suggestion(path.clone(), parent_scope))
2069 .or_else(|| self.make_missing_super_suggestion(path.clone(), parent_scope))
2070 .or_else(|| self.make_external_crate_suggestion(path, parent_scope))
2073 /// Suggest a missing `self::` if that resolves to an correct module.
2077 /// LL | use foo::Bar;
2078 /// | ^^^ did you mean `self::foo`?
2080 fn make_missing_self_suggestion(
2082 mut path: Vec<Segment>,
2083 parent_scope: &ParentScope<'b>,
2084 ) -> Option<(Vec<Segment>, Option<String>)> {
2085 // Replace first ident with `self` and check if that is valid.
2086 path[0].ident.name = kw::SelfLower;
2087 let result = self.r.maybe_resolve_path(&path, None, parent_scope);
2088 debug!("make_missing_self_suggestion: path={:?} result={:?}", path, result);
2089 if let PathResult::Module(..) = result { Some((path, None)) } else { None }
2092 /// Suggests a missing `crate::` if that resolves to an correct module.
2096 /// LL | use foo::Bar;
2097 /// | ^^^ did you mean `crate::foo`?
2099 fn make_missing_crate_suggestion(
2101 mut path: Vec<Segment>,
2102 parent_scope: &ParentScope<'b>,
2103 ) -> Option<(Vec<Segment>, Option<String>)> {
2104 // Replace first ident with `crate` and check if that is valid.
2105 path[0].ident.name = kw::Crate;
2106 let result = self.r.maybe_resolve_path(&path, None, parent_scope);
2107 debug!("make_missing_crate_suggestion: path={:?} result={:?}", path, result);
2108 if let PathResult::Module(..) = result {
2112 "`use` statements changed in Rust 2018; read more at \
2113 <https://doc.rust-lang.org/edition-guide/rust-2018/module-system/path-\
2123 /// Suggests a missing `super::` if that resolves to an correct module.
2127 /// LL | use foo::Bar;
2128 /// | ^^^ did you mean `super::foo`?
2130 fn make_missing_super_suggestion(
2132 mut path: Vec<Segment>,
2133 parent_scope: &ParentScope<'b>,
2134 ) -> Option<(Vec<Segment>, Option<String>)> {
2135 // Replace first ident with `crate` and check if that is valid.
2136 path[0].ident.name = kw::Super;
2137 let result = self.r.maybe_resolve_path(&path, None, parent_scope);
2138 debug!("make_missing_super_suggestion: path={:?} result={:?}", path, result);
2139 if let PathResult::Module(..) = result { Some((path, None)) } else { None }
2142 /// Suggests a missing external crate name if that resolves to an correct module.
2146 /// LL | use foobar::Baz;
2147 /// | ^^^^^^ did you mean `baz::foobar`?
2150 /// Used when importing a submodule of an external crate but missing that crate's
2151 /// name as the first part of path.
2152 fn make_external_crate_suggestion(
2154 mut path: Vec<Segment>,
2155 parent_scope: &ParentScope<'b>,
2156 ) -> Option<(Vec<Segment>, Option<String>)> {
2157 if path[1].ident.span.rust_2015() {
2161 // Sort extern crate names in *reverse* order to get
2162 // 1) some consistent ordering for emitted diagnostics, and
2163 // 2) `std` suggestions before `core` suggestions.
2164 let mut extern_crate_names =
2165 self.r.extern_prelude.iter().map(|(ident, _)| ident.name).collect::<Vec<_>>();
2166 extern_crate_names.sort_by(|a, b| b.as_str().partial_cmp(a.as_str()).unwrap());
2168 for name in extern_crate_names.into_iter() {
2169 // Replace first ident with a crate name and check if that is valid.
2170 path[0].ident.name = name;
2171 let result = self.r.maybe_resolve_path(&path, None, parent_scope);
2173 "make_external_crate_suggestion: name={:?} path={:?} result={:?}",
2176 if let PathResult::Module(..) = result {
2177 return Some((path, None));
2184 /// Suggests importing a macro from the root of the crate rather than a module within
2188 /// help: a macro with this name exists at the root of the crate
2190 /// LL | use issue_59764::makro;
2191 /// | ^^^^^^^^^^^^^^^^^^
2193 /// = note: this could be because a macro annotated with `#[macro_export]` will be exported
2194 /// at the root of the crate instead of the module where it is defined
2196 pub(crate) fn check_for_module_export_macro(
2198 import: &'b Import<'b>,
2199 module: ModuleOrUniformRoot<'b>,
2201 ) -> Option<(Option<Suggestion>, Option<String>)> {
2202 let ModuleOrUniformRoot::Module(mut crate_module) = module else {
2206 while let Some(parent) = crate_module.parent {
2207 crate_module = parent;
2210 if ModuleOrUniformRoot::same_def(ModuleOrUniformRoot::Module(crate_module), module) {
2211 // Don't make a suggestion if the import was already from the root of the
2216 let resolutions = self.r.resolutions(crate_module).borrow();
2217 let resolution = resolutions.get(&self.r.new_key(ident, MacroNS))?;
2218 let binding = resolution.borrow().binding()?;
2219 if let Res::Def(DefKind::Macro(MacroKind::Bang), _) = binding.res() {
2220 let module_name = crate_module.kind.name().unwrap();
2221 let import_snippet = match import.kind {
2222 ImportKind::Single { source, target, .. } if source != target => {
2223 format!("{} as {}", source, target)
2225 _ => format!("{}", ident),
2228 let mut corrections: Vec<(Span, String)> = Vec::new();
2229 if !import.is_nested() {
2230 // Assume this is the easy case of `use issue_59764::foo::makro;` and just remove
2231 // intermediate segments.
2232 corrections.push((import.span, format!("{}::{}", module_name, import_snippet)));
2234 // Find the binding span (and any trailing commas and spaces).
2235 // ie. `use a::b::{c, d, e};`
2237 let (found_closing_brace, binding_span) = find_span_of_binding_until_next_binding(
2243 "check_for_module_export_macro: found_closing_brace={:?} binding_span={:?}",
2244 found_closing_brace, binding_span
2247 let mut removal_span = binding_span;
2248 if found_closing_brace {
2249 // If the binding span ended with a closing brace, as in the below example:
2250 // ie. `use a::b::{c, d};`
2252 // Then expand the span of characters to remove to include the previous
2253 // binding's trailing comma.
2254 // ie. `use a::b::{c, d};`
2256 if let Some(previous_span) =
2257 extend_span_to_previous_binding(self.r.session, binding_span)
2259 debug!("check_for_module_export_macro: previous_span={:?}", previous_span);
2260 removal_span = removal_span.with_lo(previous_span.lo());
2263 debug!("check_for_module_export_macro: removal_span={:?}", removal_span);
2265 // Remove the `removal_span`.
2266 corrections.push((removal_span, "".to_string()));
2268 // Find the span after the crate name and if it has nested imports immediately
2269 // after the crate name already.
2270 // ie. `use a::b::{c, d};`
2272 // or `use a::{b, c, d}};`
2274 let (has_nested, after_crate_name) = find_span_immediately_after_crate_name(
2280 "check_for_module_export_macro: has_nested={:?} after_crate_name={:?}",
2281 has_nested, after_crate_name
2284 let source_map = self.r.session.source_map();
2286 // Add the import to the start, with a `{` if required.
2287 let start_point = source_map.start_point(after_crate_name);
2288 if let Ok(start_snippet) = source_map.span_to_snippet(start_point) {
2292 // In this case, `start_snippet` must equal '{'.
2293 format!("{}{}, ", start_snippet, import_snippet)
2295 // In this case, add a `{`, then the moved import, then whatever
2296 // was there before.
2297 format!("{{{}, {}", import_snippet, start_snippet)
2302 // Add a `};` to the end if nested, matching the `{` added at the start.
2304 corrections.push((source_map.end_point(after_crate_name), "};".to_string()));
2308 let suggestion = Some((
2310 String::from("a macro with this name exists at the root of the crate"),
2311 Applicability::MaybeIncorrect,
2313 Some((suggestion, Some("this could be because a macro annotated with `#[macro_export]` will be exported \
2314 at the root of the crate instead of the module where it is defined"
2322 /// Given a `binding_span` of a binding within a use statement:
2324 /// ```ignore (illustrative)
2325 /// use foo::{a, b, c};
2329 /// then return the span until the next binding or the end of the statement:
2331 /// ```ignore (illustrative)
2332 /// use foo::{a, b, c};
2335 fn find_span_of_binding_until_next_binding(
2340 let source_map = sess.source_map();
2342 // Find the span of everything after the binding.
2343 // ie. `a, e};` or `a};`
2344 let binding_until_end = binding_span.with_hi(use_span.hi());
2346 // Find everything after the binding but not including the binding.
2347 // ie. `, e};` or `};`
2348 let after_binding_until_end = binding_until_end.with_lo(binding_span.hi());
2350 // Keep characters in the span until we encounter something that isn't a comma or
2354 // Also note whether a closing brace character was encountered. If there
2355 // was, then later go backwards to remove any trailing commas that are left.
2356 let mut found_closing_brace = false;
2357 let after_binding_until_next_binding =
2358 source_map.span_take_while(after_binding_until_end, |&ch| {
2360 found_closing_brace = true;
2362 ch == ' ' || ch == ','
2365 // Combine the two spans.
2366 // ie. `a, ` or `a`.
2368 // Removing these would leave `issue_52891::{d, e};` or `issue_52891::{d, e, };`
2369 let span = binding_span.with_hi(after_binding_until_next_binding.hi());
2371 (found_closing_brace, span)
2374 /// Given a `binding_span`, return the span through to the comma or opening brace of the previous
2377 /// ```ignore (illustrative)
2378 /// use foo::a::{a, b, c};
2379 /// // ^^--- binding span
2381 /// // returned span
2383 /// use foo::{a, b, c};
2384 /// // --- binding span
2386 fn extend_span_to_previous_binding(sess: &Session, binding_span: Span) -> Option<Span> {
2387 let source_map = sess.source_map();
2389 // `prev_source` will contain all of the source that came before the span.
2390 // Then split based on a command and take the first (ie. closest to our span)
2391 // snippet. In the example, this is a space.
2392 let prev_source = source_map.span_to_prev_source(binding_span).ok()?;
2394 let prev_comma = prev_source.rsplit(',').collect::<Vec<_>>();
2395 let prev_starting_brace = prev_source.rsplit('{').collect::<Vec<_>>();
2396 if prev_comma.len() <= 1 || prev_starting_brace.len() <= 1 {
2400 let prev_comma = prev_comma.first().unwrap();
2401 let prev_starting_brace = prev_starting_brace.first().unwrap();
2403 // If the amount of source code before the comma is greater than
2404 // the amount of source code before the starting brace then we've only
2405 // got one item in the nested item (eg. `issue_52891::{self}`).
2406 if prev_comma.len() > prev_starting_brace.len() {
2410 Some(binding_span.with_lo(BytePos(
2411 // Take away the number of bytes for the characters we've found and an
2412 // extra for the comma.
2413 binding_span.lo().0 - (prev_comma.as_bytes().len() as u32) - 1,
2417 /// Given a `use_span` of a binding within a use statement, returns the highlighted span and if
2418 /// it is a nested use tree.
2420 /// ```ignore (illustrative)
2421 /// use foo::a::{b, c};
2422 /// // ^^^^^^^^^^ -- false
2424 /// use foo::{a, b, c};
2425 /// // ^^^^^^^^^^ -- true
2427 /// use foo::{a, b::{c, d}};
2428 /// // ^^^^^^^^^^^^^^^ -- true
2430 fn find_span_immediately_after_crate_name(
2432 module_name: Symbol,
2436 "find_span_immediately_after_crate_name: module_name={:?} use_span={:?}",
2437 module_name, use_span
2439 let source_map = sess.source_map();
2441 // Using `use issue_59764::foo::{baz, makro};` as an example throughout..
2442 let mut num_colons = 0;
2443 // Find second colon.. `use issue_59764:`
2444 let until_second_colon = source_map.span_take_while(use_span, |c| {
2448 !matches!(c, ':' if num_colons == 2)
2450 // Find everything after the second colon.. `foo::{baz, makro};`
2451 let from_second_colon = use_span.with_lo(until_second_colon.hi() + BytePos(1));
2453 let mut found_a_non_whitespace_character = false;
2454 // Find the first non-whitespace character in `from_second_colon`.. `f`
2455 let after_second_colon = source_map.span_take_while(from_second_colon, |c| {
2456 if found_a_non_whitespace_character {
2459 if !c.is_whitespace() {
2460 found_a_non_whitespace_character = true;
2465 // Find the first `{` in from_second_colon.. `foo::{`
2466 let next_left_bracket = source_map.span_through_char(from_second_colon, '{');
2468 (next_left_bracket == after_second_colon, from_second_colon)
2471 /// A suggestion has already been emitted, change the wording slightly to clarify that both are
2472 /// independent options.
2478 /// Whether an existing place with an `use` item was found.
2484 /// Whether a binding is part of a pattern or a use statement. Used for diagnostics.
2485 enum DiagnosticMode {
2487 /// The binding is part of a pattern
2489 /// The binding is part of a use statement
2493 pub(crate) fn import_candidates(
2495 source_span: &IndexVec<LocalDefId, Span>,
2496 err: &mut Diagnostic,
2497 // This is `None` if all placement locations are inside expansions
2498 use_placement_span: Option<Span>,
2499 candidates: &[ImportSuggestion],
2509 DiagnosticMode::Import,
2514 /// When an entity with a given name is not available in scope, we search for
2515 /// entities with that name in all crates. This method allows outputting the
2516 /// results of this search in a programmer-friendly way
2519 source_span: &IndexVec<LocalDefId, Span>,
2520 err: &mut Diagnostic,
2521 // This is `None` if all placement locations are inside expansions
2522 use_placement_span: Option<Span>,
2523 candidates: &[ImportSuggestion],
2525 found_use: FoundUse,
2526 mode: DiagnosticMode,
2529 if candidates.is_empty() {
2533 let mut accessible_path_strings: Vec<(String, &str, Option<DefId>, &Option<String>)> =
2535 let mut inaccessible_path_strings: Vec<(String, &str, Option<DefId>, &Option<String>)> =
2538 candidates.iter().for_each(|c| {
2539 (if c.accessible { &mut accessible_path_strings } else { &mut inaccessible_path_strings })
2540 .push((path_names_to_string(&c.path), c.descr, c.did, &c.note))
2543 // we want consistent results across executions, but candidates are produced
2544 // by iterating through a hash map, so make sure they are ordered:
2545 for path_strings in [&mut accessible_path_strings, &mut inaccessible_path_strings] {
2546 path_strings.sort_by(|a, b| a.0.cmp(&b.0));
2547 let core_path_strings =
2548 path_strings.drain_filter(|p| p.0.starts_with("core::")).collect::<Vec<_>>();
2549 path_strings.extend(core_path_strings);
2550 path_strings.dedup_by(|a, b| a.0 == b.0);
2553 if !accessible_path_strings.is_empty() {
2554 let (determiner, kind, name) = if accessible_path_strings.len() == 1 {
2555 ("this", accessible_path_strings[0].1, format!(" `{}`", accessible_path_strings[0].0))
2557 ("one of these", "items", String::new())
2560 let instead = if let Instead::Yes = instead { " instead" } else { "" };
2561 let mut msg = if let DiagnosticMode::Pattern = mode {
2563 "if you meant to match on {}{}{}, use the full path in the pattern",
2567 format!("consider importing {} {}{}", determiner, kind, instead)
2570 for note in accessible_path_strings.iter().flat_map(|cand| cand.3.as_ref()) {
2574 if let Some(span) = use_placement_span {
2575 let add_use = match mode {
2576 DiagnosticMode::Pattern => {
2577 err.span_suggestions(
2580 accessible_path_strings.into_iter().map(|a| a.0),
2581 Applicability::MaybeIncorrect,
2585 DiagnosticMode::Import => "",
2586 DiagnosticMode::Normal => "use ",
2588 for candidate in &mut accessible_path_strings {
2589 // produce an additional newline to separate the new use statement
2590 // from the directly following item.
2591 let additional_newline = if let FoundUse::Yes = found_use { "" } else { "\n" };
2592 candidate.0 = format!("{}{};\n{}", add_use, &candidate.0, additional_newline);
2595 err.span_suggestions(
2598 accessible_path_strings.into_iter().map(|a| a.0),
2599 Applicability::MaybeIncorrect,
2601 if let [first, .., last] = &path[..] {
2602 let sp = first.ident.span.until(last.ident.span);
2603 if sp.can_be_used_for_suggestions() {
2604 err.span_suggestion_verbose(
2606 &format!("if you import `{}`, refer to it directly", last.ident),
2608 Applicability::Unspecified,
2615 for candidate in accessible_path_strings {
2617 msg.push_str(&candidate.0);
2622 } else if !matches!(mode, DiagnosticMode::Import) {
2623 assert!(!inaccessible_path_strings.is_empty());
2625 let prefix = if let DiagnosticMode::Pattern = mode {
2626 "you might have meant to match on "
2630 if inaccessible_path_strings.len() == 1 {
2631 let (name, descr, def_id, note) = &inaccessible_path_strings[0];
2633 "{}{} `{}`{} exists but is inaccessible",
2637 if let DiagnosticMode::Pattern = mode { ", which" } else { "" }
2640 if let Some(local_def_id) = def_id.and_then(|did| did.as_local()) {
2641 let span = source_span[local_def_id];
2642 let span = session.source_map().guess_head_span(span);
2643 let mut multi_span = MultiSpan::from_span(span);
2644 multi_span.push_span_label(span, "not accessible");
2645 err.span_note(multi_span, &msg);
2649 if let Some(note) = (*note).as_deref() {
2653 let (_, descr_first, _, _) = &inaccessible_path_strings[0];
2654 let descr = if inaccessible_path_strings
2657 .all(|(_, descr, _, _)| descr == descr_first)
2664 if descr.ends_with('s') { format!("{}es", descr) } else { format!("{}s", descr) };
2666 let mut msg = format!("{}these {} exist but are inaccessible", prefix, plural_descr);
2667 let mut has_colon = false;
2669 let mut spans = Vec::new();
2670 for (name, _, def_id, _) in &inaccessible_path_strings {
2671 if let Some(local_def_id) = def_id.and_then(|did| did.as_local()) {
2672 let span = source_span[local_def_id];
2673 let span = session.source_map().guess_head_span(span);
2674 spans.push((name, span));
2685 let mut multi_span = MultiSpan::from_spans(spans.iter().map(|(_, sp)| *sp).collect());
2686 for (name, span) in spans {
2687 multi_span.push_span_label(span, format!("`{}`: not accessible", name));
2690 for note in inaccessible_path_strings.iter().flat_map(|cand| cand.3.as_ref()) {
2694 err.span_note(multi_span, &msg);
2700 struct UsePlacementFinder {
2701 target_module: NodeId,
2702 first_legal_span: Option<Span>,
2703 first_use_span: Option<Span>,
2706 impl UsePlacementFinder {
2707 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, FoundUse) {
2709 UsePlacementFinder { target_module, first_legal_span: None, first_use_span: None };
2710 finder.visit_crate(krate);
2711 if let Some(use_span) = finder.first_use_span {
2712 (Some(use_span), FoundUse::Yes)
2714 (finder.first_legal_span, FoundUse::No)
2719 impl<'tcx> visit::Visitor<'tcx> for UsePlacementFinder {
2720 fn visit_crate(&mut self, c: &Crate) {
2721 if self.target_module == CRATE_NODE_ID {
2722 let inject = c.spans.inject_use_span;
2723 if is_span_suitable_for_use_injection(inject) {
2724 self.first_legal_span = Some(inject);
2726 self.first_use_span = search_for_any_use_in_items(&c.items);
2729 visit::walk_crate(self, c);
2733 fn visit_item(&mut self, item: &'tcx ast::Item) {
2734 if self.target_module == item.id {
2735 if let ItemKind::Mod(_, ModKind::Loaded(items, _inline, mod_spans)) = &item.kind {
2736 let inject = mod_spans.inject_use_span;
2737 if is_span_suitable_for_use_injection(inject) {
2738 self.first_legal_span = Some(inject);
2740 self.first_use_span = search_for_any_use_in_items(items);
2744 visit::walk_item(self, item);
2749 fn search_for_any_use_in_items(items: &[P<ast::Item>]) -> Option<Span> {
2751 if let ItemKind::Use(..) = item.kind {
2752 if is_span_suitable_for_use_injection(item.span) {
2753 return Some(item.span.shrink_to_lo());
2760 fn is_span_suitable_for_use_injection(s: Span) -> bool {
2761 // don't suggest placing a use before the prelude
2762 // import or other generated ones
2766 /// Convert the given number into the corresponding ordinal
2767 pub(crate) fn ordinalize(v: usize) -> String {
2768 let suffix = match ((11..=13).contains(&(v % 100)), v % 10) {
2774 format!("{v}{suffix}")