1use std::cell::Cell;
4use std::mem;
5
6use rustc_ast::NodeId;
7use rustc_data_structures::fx::{FxHashSet, FxIndexSet};
8use rustc_data_structures::intern::Interned;
9use rustc_errors::codes::*;
10use rustc_errors::{Applicability, MultiSpan, pluralize, struct_span_code_err};
11use rustc_hir::def::{self, DefKind, PartialRes};
12use rustc_hir::def_id::DefId;
13use rustc_middle::metadata::{ModChild, Reexport};
14use rustc_middle::{span_bug, ty};
15use rustc_session::lint::BuiltinLintDiag;
16use rustc_session::lint::builtin::{
17 AMBIGUOUS_GLOB_REEXPORTS, HIDDEN_GLOB_REEXPORTS, PUB_USE_OF_PRIVATE_EXTERN_CRATE,
18 REDUNDANT_IMPORTS, UNUSED_IMPORTS,
19};
20use rustc_session::parse::feature_err;
21use rustc_span::edit_distance::find_best_match_for_name;
22use rustc_span::hygiene::LocalExpnId;
23use rustc_span::{Ident, Span, Symbol, kw, sym};
24use smallvec::SmallVec;
25use tracing::debug;
26
27use crate::Determinacy::{self, *};
28use crate::Namespace::*;
29use crate::diagnostics::{DiagMode, Suggestion, import_candidates};
30use crate::errors::{
31 CannotBeReexportedCratePublic, CannotBeReexportedCratePublicNS, CannotBeReexportedPrivate,
32 CannotBeReexportedPrivateNS, CannotDetermineImportResolution, CannotGlobImportAllCrates,
33 ConsiderAddingMacroExport, ConsiderMarkingAsPub,
34};
35use crate::{
36 AmbiguityError, AmbiguityKind, BindingKey, Finalize, ImportSuggestion, Module,
37 ModuleOrUniformRoot, NameBinding, NameBindingData, NameBindingKind, ParentScope, PathResult,
38 PerNS, ResolutionError, Resolver, ScopeSet, Segment, Used, module_to_string, names_to_string,
39};
40
41type Res = def::Res<NodeId>;
42
43#[derive(Clone)]
45pub(crate) enum ImportKind<'ra> {
46 Single {
47 source: Ident,
49 target: Ident,
52 source_bindings: PerNS<Cell<Result<NameBinding<'ra>, Determinacy>>>,
54 target_bindings: PerNS<Cell<Option<NameBinding<'ra>>>>,
56 type_ns_only: bool,
58 nested: bool,
60 id: NodeId,
72 },
73 Glob {
74 is_prelude: bool,
75 max_vis: Cell<Option<ty::Visibility>>,
78 id: NodeId,
79 },
80 ExternCrate {
81 source: Option<Symbol>,
82 target: Ident,
83 id: NodeId,
84 },
85 MacroUse {
86 warn_private: bool,
89 },
90 MacroExport,
91}
92
93impl<'ra> std::fmt::Debug for ImportKind<'ra> {
96 fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
97 use ImportKind::*;
98 match self {
99 Single {
100 source,
101 target,
102 source_bindings,
103 target_bindings,
104 type_ns_only,
105 nested,
106 id,
107 } => f
108 .debug_struct("Single")
109 .field("source", source)
110 .field("target", target)
111 .field(
113 "source_bindings",
114 &source_bindings.clone().map(|b| b.into_inner().map(|_| format_args!(".."))),
115 )
116 .field(
117 "target_bindings",
118 &target_bindings.clone().map(|b| b.into_inner().map(|_| format_args!(".."))),
119 )
120 .field("type_ns_only", type_ns_only)
121 .field("nested", nested)
122 .field("id", id)
123 .finish(),
124 Glob { is_prelude, max_vis, id } => f
125 .debug_struct("Glob")
126 .field("is_prelude", is_prelude)
127 .field("max_vis", max_vis)
128 .field("id", id)
129 .finish(),
130 ExternCrate { source, target, id } => f
131 .debug_struct("ExternCrate")
132 .field("source", source)
133 .field("target", target)
134 .field("id", id)
135 .finish(),
136 MacroUse { .. } => f.debug_struct("MacroUse").finish(),
137 MacroExport => f.debug_struct("MacroExport").finish(),
138 }
139 }
140}
141
142#[derive(Debug, Clone)]
144pub(crate) struct ImportData<'ra> {
145 pub kind: ImportKind<'ra>,
146
147 pub root_id: NodeId,
157
158 pub use_span: Span,
160
161 pub use_span_with_attributes: Span,
163
164 pub has_attributes: bool,
166
167 pub span: Span,
169
170 pub root_span: Span,
172
173 pub parent_scope: ParentScope<'ra>,
174 pub module_path: Vec<Segment>,
175 pub imported_module: Cell<Option<ModuleOrUniformRoot<'ra>>>,
177 pub vis: ty::Visibility,
178}
179
180pub(crate) type Import<'ra> = Interned<'ra, ImportData<'ra>>;
183
184impl std::hash::Hash for ImportData<'_> {
189 fn hash<H>(&self, _: &mut H)
190 where
191 H: std::hash::Hasher,
192 {
193 unreachable!()
194 }
195}
196
197impl<'ra> ImportData<'ra> {
198 pub(crate) fn is_glob(&self) -> bool {
199 matches!(self.kind, ImportKind::Glob { .. })
200 }
201
202 pub(crate) fn is_nested(&self) -> bool {
203 match self.kind {
204 ImportKind::Single { nested, .. } => nested,
205 _ => false,
206 }
207 }
208
209 pub(crate) fn id(&self) -> Option<NodeId> {
210 match self.kind {
211 ImportKind::Single { id, .. }
212 | ImportKind::Glob { id, .. }
213 | ImportKind::ExternCrate { id, .. } => Some(id),
214 ImportKind::MacroUse { .. } | ImportKind::MacroExport => None,
215 }
216 }
217
218 fn simplify(&self, r: &Resolver<'_, '_>) -> Reexport {
219 let to_def_id = |id| r.local_def_id(id).to_def_id();
220 match self.kind {
221 ImportKind::Single { id, .. } => Reexport::Single(to_def_id(id)),
222 ImportKind::Glob { id, .. } => Reexport::Glob(to_def_id(id)),
223 ImportKind::ExternCrate { id, .. } => Reexport::ExternCrate(to_def_id(id)),
224 ImportKind::MacroUse { .. } => Reexport::MacroUse,
225 ImportKind::MacroExport => Reexport::MacroExport,
226 }
227 }
228}
229
230#[derive(Clone, Default, Debug)]
232pub(crate) struct NameResolution<'ra> {
233 pub single_imports: FxIndexSet<Import<'ra>>,
236 pub binding: Option<NameBinding<'ra>>,
238 pub shadowed_glob: Option<NameBinding<'ra>>,
239}
240
241impl<'ra> NameResolution<'ra> {
242 pub(crate) fn binding(&self) -> Option<NameBinding<'ra>> {
244 self.binding.and_then(|binding| {
245 if !binding.is_glob_import() || self.single_imports.is_empty() {
246 Some(binding)
247 } else {
248 None
249 }
250 })
251 }
252}
253
254#[derive(Debug, Clone)]
257struct UnresolvedImportError {
258 span: Span,
259 label: Option<String>,
260 note: Option<String>,
261 suggestion: Option<Suggestion>,
262 candidates: Option<Vec<ImportSuggestion>>,
263 segment: Option<Symbol>,
264 module: Option<DefId>,
266}
267
268fn pub_use_of_private_extern_crate_hack(
271 import: Import<'_>,
272 binding: NameBinding<'_>,
273) -> Option<NodeId> {
274 match (&import.kind, &binding.kind) {
275 (ImportKind::Single { .. }, NameBindingKind::Import { import: binding_import, .. })
276 if let ImportKind::ExternCrate { id, .. } = binding_import.kind
277 && import.vis.is_public() =>
278 {
279 Some(id)
280 }
281 _ => None,
282 }
283}
284
285impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
286 pub(crate) fn import(
289 &self,
290 binding: NameBinding<'ra>,
291 import: Import<'ra>,
292 ) -> NameBinding<'ra> {
293 let import_vis = import.vis.to_def_id();
294 let vis = if binding.vis.is_at_least(import_vis, self.tcx)
295 || pub_use_of_private_extern_crate_hack(import, binding).is_some()
296 {
297 import_vis
298 } else {
299 binding.vis
300 };
301
302 if let ImportKind::Glob { ref max_vis, .. } = import.kind
303 && (vis == import_vis
304 || max_vis.get().is_none_or(|max_vis| vis.is_at_least(max_vis, self.tcx)))
305 {
306 max_vis.set(Some(vis.expect_local()))
307 }
308
309 self.arenas.alloc_name_binding(NameBindingData {
310 kind: NameBindingKind::Import { binding, import },
311 ambiguity: None,
312 warn_ambiguity: false,
313 span: import.span,
314 vis,
315 expansion: import.parent_scope.expansion,
316 })
317 }
318
319 pub(crate) fn try_define(
322 &mut self,
323 module: Module<'ra>,
324 key: BindingKey,
325 binding: NameBinding<'ra>,
326 warn_ambiguity: bool,
327 ) -> Result<(), NameBinding<'ra>> {
328 let res = binding.res();
329 self.check_reserved_macro_name(key.ident, res);
330 self.set_binding_parent_module(binding, module);
331 self.update_resolution(module, key, warn_ambiguity, |this, resolution| {
332 if let Some(old_binding) = resolution.binding {
333 if res == Res::Err && old_binding.res() != Res::Err {
334 return Ok(());
336 }
337 match (old_binding.is_glob_import(), binding.is_glob_import()) {
338 (true, true) => {
339 if !binding.is_ambiguity_recursive()
341 && let NameBindingKind::Import { import: old_import, .. } =
342 old_binding.kind
343 && let NameBindingKind::Import { import, .. } = binding.kind
344 && old_import == import
345 {
346 resolution.binding = Some(binding);
350 } else if res != old_binding.res() {
351 resolution.binding = Some(this.new_ambiguity_binding(
352 AmbiguityKind::GlobVsGlob,
353 old_binding,
354 binding,
355 warn_ambiguity,
356 ));
357 } else if !old_binding.vis.is_at_least(binding.vis, this.tcx) {
358 resolution.binding = Some(binding);
360 } else if binding.is_ambiguity_recursive() {
361 resolution.binding = Some(this.new_warn_ambiguity_binding(binding));
362 }
363 }
364 (old_glob @ true, false) | (old_glob @ false, true) => {
365 let (glob_binding, nonglob_binding) =
366 if old_glob { (old_binding, binding) } else { (binding, old_binding) };
367 if key.ns == MacroNS
368 && nonglob_binding.expansion != LocalExpnId::ROOT
369 && glob_binding.res() != nonglob_binding.res()
370 {
371 resolution.binding = Some(this.new_ambiguity_binding(
372 AmbiguityKind::GlobVsExpanded,
373 nonglob_binding,
374 glob_binding,
375 false,
376 ));
377 } else {
378 resolution.binding = Some(nonglob_binding);
379 }
380
381 if let Some(old_shadowed_glob) = resolution.shadowed_glob {
382 assert!(old_shadowed_glob.is_glob_import());
383 if glob_binding.res() != old_shadowed_glob.res() {
384 resolution.shadowed_glob = Some(this.new_ambiguity_binding(
385 AmbiguityKind::GlobVsGlob,
386 old_shadowed_glob,
387 glob_binding,
388 false,
389 ));
390 } else if !old_shadowed_glob.vis.is_at_least(binding.vis, this.tcx) {
391 resolution.shadowed_glob = Some(glob_binding);
392 }
393 } else {
394 resolution.shadowed_glob = Some(glob_binding);
395 }
396 }
397 (false, false) => {
398 return Err(old_binding);
399 }
400 }
401 } else {
402 resolution.binding = Some(binding);
403 }
404
405 Ok(())
406 })
407 }
408
409 fn new_ambiguity_binding(
410 &self,
411 ambiguity_kind: AmbiguityKind,
412 primary_binding: NameBinding<'ra>,
413 secondary_binding: NameBinding<'ra>,
414 warn_ambiguity: bool,
415 ) -> NameBinding<'ra> {
416 let ambiguity = Some((secondary_binding, ambiguity_kind));
417 let data = NameBindingData { ambiguity, warn_ambiguity, ..*primary_binding };
418 self.arenas.alloc_name_binding(data)
419 }
420
421 fn new_warn_ambiguity_binding(&self, binding: NameBinding<'ra>) -> NameBinding<'ra> {
422 assert!(binding.is_ambiguity_recursive());
423 self.arenas.alloc_name_binding(NameBindingData { warn_ambiguity: true, ..*binding })
424 }
425
426 fn update_resolution<T, F>(
429 &mut self,
430 module: Module<'ra>,
431 key: BindingKey,
432 warn_ambiguity: bool,
433 f: F,
434 ) -> T
435 where
436 F: FnOnce(&mut Resolver<'ra, 'tcx>, &mut NameResolution<'ra>) -> T,
437 {
438 let (binding, t, warn_ambiguity) = {
441 let resolution = &mut *self.resolution(module, key).borrow_mut();
442 let old_binding = resolution.binding();
443
444 let t = f(self, resolution);
445
446 if let Some(binding) = resolution.binding()
447 && old_binding != Some(binding)
448 {
449 (binding, t, warn_ambiguity || old_binding.is_some())
450 } else {
451 return t;
452 }
453 };
454
455 let Ok(glob_importers) = module.glob_importers.try_borrow_mut() else {
456 return t;
457 };
458
459 for import in glob_importers.iter() {
461 let mut ident = key.ident;
462 let scope = match ident.span.reverse_glob_adjust(module.expansion, import.span) {
463 Some(Some(def)) => self.expn_def_scope(def),
464 Some(None) => import.parent_scope.module,
465 None => continue,
466 };
467 if self.is_accessible_from(binding.vis, scope) {
468 let imported_binding = self.import(binding, *import);
469 let key = BindingKey { ident, ..key };
470 let _ = self.try_define(
471 import.parent_scope.module,
472 key,
473 imported_binding,
474 warn_ambiguity,
475 );
476 }
477 }
478
479 t
480 }
481
482 fn import_dummy_binding(&mut self, import: Import<'ra>, is_indeterminate: bool) {
485 if let ImportKind::Single { target, ref target_bindings, .. } = import.kind {
486 if !(is_indeterminate || target_bindings.iter().all(|binding| binding.get().is_none()))
487 {
488 return; }
490 let dummy_binding = self.dummy_binding;
491 let dummy_binding = self.import(dummy_binding, import);
492 self.per_ns(|this, ns| {
493 let key = BindingKey::new(target, ns);
494 let _ = this.try_define(import.parent_scope.module, key, dummy_binding, false);
495 this.update_resolution(import.parent_scope.module, key, false, |_, resolution| {
496 resolution.single_imports.swap_remove(&import);
497 })
498 });
499 self.record_use(target, dummy_binding, Used::Other);
500 } else if import.imported_module.get().is_none() {
501 self.import_use_map.insert(import, Used::Other);
502 if let Some(id) = import.id() {
503 self.used_imports.insert(id);
504 }
505 }
506 }
507
508 pub(crate) fn resolve_imports(&mut self) {
519 let mut prev_indeterminate_count = usize::MAX;
520 let mut indeterminate_count = self.indeterminate_imports.len() * 3;
521 while indeterminate_count < prev_indeterminate_count {
522 prev_indeterminate_count = indeterminate_count;
523 indeterminate_count = 0;
524 for import in mem::take(&mut self.indeterminate_imports) {
525 let import_indeterminate_count = self.resolve_import(import);
526 indeterminate_count += import_indeterminate_count;
527 match import_indeterminate_count {
528 0 => self.determined_imports.push(import),
529 _ => self.indeterminate_imports.push(import),
530 }
531 }
532 }
533 }
534
535 pub(crate) fn finalize_imports(&mut self) {
536 for module in self.arenas.local_modules().iter() {
537 self.finalize_resolutions_in(*module);
538 }
539
540 let mut seen_spans = FxHashSet::default();
541 let mut errors = vec![];
542 let mut prev_root_id: NodeId = NodeId::ZERO;
543 let determined_imports = mem::take(&mut self.determined_imports);
544 let indeterminate_imports = mem::take(&mut self.indeterminate_imports);
545
546 let mut glob_error = false;
547 for (is_indeterminate, import) in determined_imports
548 .iter()
549 .map(|i| (false, i))
550 .chain(indeterminate_imports.iter().map(|i| (true, i)))
551 {
552 let unresolved_import_error = self.finalize_import(*import);
553 self.import_dummy_binding(*import, is_indeterminate);
556
557 let Some(err) = unresolved_import_error else { continue };
558
559 glob_error |= import.is_glob();
560
561 if let ImportKind::Single { source, ref source_bindings, .. } = import.kind
562 && source.name == kw::SelfLower
563 && let Err(Determined) = source_bindings.value_ns.get()
565 {
566 continue;
567 }
568
569 if prev_root_id != NodeId::ZERO && prev_root_id != import.root_id && !errors.is_empty()
570 {
571 self.throw_unresolved_import_error(errors, glob_error);
574 errors = vec![];
575 }
576 if seen_spans.insert(err.span) {
577 errors.push((*import, err));
578 prev_root_id = import.root_id;
579 }
580 }
581
582 if !errors.is_empty() {
583 self.throw_unresolved_import_error(errors, glob_error);
584 return;
585 }
586
587 for import in &indeterminate_imports {
588 let path = import_path_to_string(
589 &import.module_path.iter().map(|seg| seg.ident).collect::<Vec<_>>(),
590 &import.kind,
591 import.span,
592 );
593 if path.contains("::") {
596 let err = UnresolvedImportError {
597 span: import.span,
598 label: None,
599 note: None,
600 suggestion: None,
601 candidates: None,
602 segment: None,
603 module: None,
604 };
605 errors.push((*import, err))
606 }
607 }
608
609 self.throw_unresolved_import_error(errors, glob_error);
610 }
611
612 pub(crate) fn check_hidden_glob_reexports(
613 &mut self,
614 exported_ambiguities: FxHashSet<NameBinding<'ra>>,
615 ) {
616 for module in self.arenas.local_modules().iter() {
617 for (key, resolution) in self.resolutions(*module).borrow().iter() {
618 let resolution = resolution.borrow();
619
620 let Some(binding) = resolution.binding else { continue };
621
622 if let NameBindingKind::Import { import, .. } = binding.kind
623 && let Some((amb_binding, _)) = binding.ambiguity
624 && binding.res() != Res::Err
625 && exported_ambiguities.contains(&binding)
626 {
627 self.lint_buffer.buffer_lint(
628 AMBIGUOUS_GLOB_REEXPORTS,
629 import.root_id,
630 import.root_span,
631 BuiltinLintDiag::AmbiguousGlobReexports {
632 name: key.ident.to_string(),
633 namespace: key.ns.descr().to_string(),
634 first_reexport_span: import.root_span,
635 duplicate_reexport_span: amb_binding.span,
636 },
637 );
638 }
639
640 if let Some(glob_binding) = resolution.shadowed_glob {
641 if binding.res() != Res::Err
642 && glob_binding.res() != Res::Err
643 && let NameBindingKind::Import { import: glob_import, .. } =
644 glob_binding.kind
645 && let Some(glob_import_id) = glob_import.id()
646 && let glob_import_def_id = self.local_def_id(glob_import_id)
647 && self.effective_visibilities.is_exported(glob_import_def_id)
648 && glob_binding.vis.is_public()
649 && !binding.vis.is_public()
650 {
651 let binding_id = match binding.kind {
652 NameBindingKind::Res(res) => {
653 Some(self.def_id_to_node_id(res.def_id().expect_local()))
654 }
655 NameBindingKind::Module(module) => {
656 Some(self.def_id_to_node_id(module.def_id().expect_local()))
657 }
658 NameBindingKind::Import { import, .. } => import.id(),
659 };
660 if let Some(binding_id) = binding_id {
661 self.lint_buffer.buffer_lint(
662 HIDDEN_GLOB_REEXPORTS,
663 binding_id,
664 binding.span,
665 BuiltinLintDiag::HiddenGlobReexports {
666 name: key.ident.name.to_string(),
667 namespace: key.ns.descr().to_owned(),
668 glob_reexport_span: glob_binding.span,
669 private_item_span: binding.span,
670 },
671 );
672 }
673 }
674 }
675 }
676 }
677 }
678
679 fn throw_unresolved_import_error(
680 &mut self,
681 mut errors: Vec<(Import<'_>, UnresolvedImportError)>,
682 glob_error: bool,
683 ) {
684 errors.retain(|(_import, err)| match err.module {
685 Some(def_id) if self.mods_with_parse_errors.contains(&def_id) => false,
687 _ => true,
688 });
689 if errors.is_empty() {
690 return;
691 }
692
693 const MAX_LABEL_COUNT: usize = 10;
695
696 let span = MultiSpan::from_spans(errors.iter().map(|(_, err)| err.span).collect());
697 let paths = errors
698 .iter()
699 .map(|(import, err)| {
700 let path = import_path_to_string(
701 &import.module_path.iter().map(|seg| seg.ident).collect::<Vec<_>>(),
702 &import.kind,
703 err.span,
704 );
705 format!("`{path}`")
706 })
707 .collect::<Vec<_>>();
708 let msg = format!("unresolved import{} {}", pluralize!(paths.len()), paths.join(", "),);
709
710 let mut diag = struct_span_code_err!(self.dcx(), span, E0432, "{msg}");
711
712 if let Some((_, UnresolvedImportError { note: Some(note), .. })) = errors.iter().last() {
713 diag.note(note.clone());
714 }
715
716 for (import, err) in errors.into_iter().take(MAX_LABEL_COUNT) {
717 if let Some(label) = err.label {
718 diag.span_label(err.span, label);
719 }
720
721 if let Some((suggestions, msg, applicability)) = err.suggestion {
722 if suggestions.is_empty() {
723 diag.help(msg);
724 continue;
725 }
726 diag.multipart_suggestion(msg, suggestions, applicability);
727 }
728
729 if let Some(candidates) = &err.candidates {
730 match &import.kind {
731 ImportKind::Single { nested: false, source, target, .. } => import_candidates(
732 self.tcx,
733 &mut diag,
734 Some(err.span),
735 candidates,
736 DiagMode::Import { append: false, unresolved_import: true },
737 (source != target)
738 .then(|| format!(" as {target}"))
739 .as_deref()
740 .unwrap_or(""),
741 ),
742 ImportKind::Single { nested: true, source, target, .. } => {
743 import_candidates(
744 self.tcx,
745 &mut diag,
746 None,
747 candidates,
748 DiagMode::Normal,
749 (source != target)
750 .then(|| format!(" as {target}"))
751 .as_deref()
752 .unwrap_or(""),
753 );
754 }
755 _ => {}
756 }
757 }
758
759 if matches!(import.kind, ImportKind::Single { .. })
760 && let Some(segment) = err.segment
761 && let Some(module) = err.module
762 {
763 self.find_cfg_stripped(&mut diag, &segment, module)
764 }
765 }
766
767 let guar = diag.emit();
768 if glob_error {
769 self.glob_error = Some(guar);
770 }
771 }
772
773 fn resolve_import(&mut self, import: Import<'ra>) -> usize {
780 debug!(
781 "(resolving import for module) resolving import `{}::...` in `{}`",
782 Segment::names_to_string(&import.module_path),
783 module_to_string(import.parent_scope.module).unwrap_or_else(|| "???".to_string()),
784 );
785 let module = if let Some(module) = import.imported_module.get() {
786 module
787 } else {
788 let path_res = self.maybe_resolve_path(
789 &import.module_path,
790 None,
791 &import.parent_scope,
792 Some(import),
793 );
794
795 match path_res {
796 PathResult::Module(module) => module,
797 PathResult::Indeterminate => return 3,
798 PathResult::NonModule(..) | PathResult::Failed { .. } => return 0,
799 }
800 };
801
802 import.imported_module.set(Some(module));
803 let (source, target, source_bindings, target_bindings, type_ns_only) = match import.kind {
804 ImportKind::Single {
805 source,
806 target,
807 ref source_bindings,
808 ref target_bindings,
809 type_ns_only,
810 ..
811 } => (source, target, source_bindings, target_bindings, type_ns_only),
812 ImportKind::Glob { .. } => {
813 self.resolve_glob_import(import);
814 return 0;
815 }
816 _ => unreachable!(),
817 };
818
819 let mut indeterminate_count = 0;
820 self.per_ns(|this, ns| {
821 if !type_ns_only || ns == TypeNS {
822 if let Err(Undetermined) = source_bindings[ns].get() {
823 let binding = this.maybe_resolve_ident_in_module(
824 module,
825 source,
826 ns,
827 &import.parent_scope,
828 Some(import),
829 );
830 source_bindings[ns].set(binding);
831 } else {
832 return;
833 };
834
835 let parent = import.parent_scope.module;
836 match source_bindings[ns].get() {
837 Ok(binding) => {
838 if binding.is_assoc_item()
839 && !this.tcx.features().import_trait_associated_functions()
840 {
841 feature_err(
842 this.tcx.sess,
843 sym::import_trait_associated_functions,
844 import.span,
845 "`use` associated items of traits is unstable",
846 )
847 .emit();
848 }
849
850 let imported_binding = this.import(binding, import);
851 target_bindings[ns].set(Some(imported_binding));
852 this.define(parent, target, ns, imported_binding);
853 }
854 Err(Determined) => {
855 if target.name != kw::Underscore {
857 let key = BindingKey::new(target, ns);
858 this.update_resolution(parent, key, false, |_, resolution| {
859 resolution.single_imports.swap_remove(&import);
860 });
861 }
862 }
863 Err(Undetermined) => indeterminate_count += 1,
864 }
865 }
866 });
867
868 indeterminate_count
869 }
870
871 fn finalize_import(&mut self, import: Import<'ra>) -> Option<UnresolvedImportError> {
876 let ignore_binding = match &import.kind {
877 ImportKind::Single { target_bindings, .. } => target_bindings[TypeNS].get(),
878 _ => None,
879 };
880 let ambiguity_errors_len =
881 |errors: &Vec<AmbiguityError<'_>>| errors.iter().filter(|error| !error.warning).count();
882 let prev_ambiguity_errors_len = ambiguity_errors_len(&self.ambiguity_errors);
883 let finalize = Finalize::with_root_span(import.root_id, import.span, import.root_span);
884
885 let privacy_errors_len = self.privacy_errors.len();
887
888 let path_res = self.resolve_path(
889 &import.module_path,
890 None,
891 &import.parent_scope,
892 Some(finalize),
893 ignore_binding,
894 Some(import),
895 );
896
897 let no_ambiguity =
898 ambiguity_errors_len(&self.ambiguity_errors) == prev_ambiguity_errors_len;
899
900 let module = match path_res {
901 PathResult::Module(module) => {
902 if let Some(initial_module) = import.imported_module.get() {
904 if module != initial_module && no_ambiguity {
905 span_bug!(import.span, "inconsistent resolution for an import");
906 }
907 } else if self.privacy_errors.is_empty() {
908 self.dcx()
909 .create_err(CannotDetermineImportResolution { span: import.span })
910 .emit();
911 }
912
913 module
914 }
915 PathResult::Failed {
916 is_error_from_last_segment: false,
917 span,
918 segment_name,
919 label,
920 suggestion,
921 module,
922 error_implied_by_parse_error: _,
923 } => {
924 if no_ambiguity {
925 assert!(import.imported_module.get().is_none());
926 self.report_error(
927 span,
928 ResolutionError::FailedToResolve {
929 segment: Some(segment_name),
930 label,
931 suggestion,
932 module,
933 },
934 );
935 }
936 return None;
937 }
938 PathResult::Failed {
939 is_error_from_last_segment: true,
940 span,
941 label,
942 suggestion,
943 module,
944 segment_name,
945 ..
946 } => {
947 if no_ambiguity {
948 assert!(import.imported_module.get().is_none());
949 let module = if let Some(ModuleOrUniformRoot::Module(m)) = module {
950 m.opt_def_id()
951 } else {
952 None
953 };
954 let err = match self
955 .make_path_suggestion(import.module_path.clone(), &import.parent_scope)
956 {
957 Some((suggestion, note)) => UnresolvedImportError {
958 span,
959 label: None,
960 note,
961 suggestion: Some((
962 vec![(span, Segment::names_to_string(&suggestion))],
963 String::from("a similar path exists"),
964 Applicability::MaybeIncorrect,
965 )),
966 candidates: None,
967 segment: Some(segment_name),
968 module,
969 },
970 None => UnresolvedImportError {
971 span,
972 label: Some(label),
973 note: None,
974 suggestion,
975 candidates: None,
976 segment: Some(segment_name),
977 module,
978 },
979 };
980 return Some(err);
981 }
982 return None;
983 }
984 PathResult::NonModule(partial_res) => {
985 if no_ambiguity && partial_res.full_res() != Some(Res::Err) {
986 assert!(import.imported_module.get().is_none());
988 }
989 return None;
991 }
992 PathResult::Indeterminate => unreachable!(),
993 };
994
995 let (ident, target, source_bindings, target_bindings, type_ns_only, import_id) =
996 match import.kind {
997 ImportKind::Single {
998 source,
999 target,
1000 ref source_bindings,
1001 ref target_bindings,
1002 type_ns_only,
1003 id,
1004 ..
1005 } => (source, target, source_bindings, target_bindings, type_ns_only, id),
1006 ImportKind::Glob { is_prelude, ref max_vis, id } => {
1007 if import.module_path.len() <= 1 {
1008 let mut full_path = import.module_path.clone();
1011 full_path.push(Segment::from_ident(Ident::dummy()));
1012 self.lint_if_path_starts_with_module(Some(finalize), &full_path, None);
1013 }
1014
1015 if let ModuleOrUniformRoot::Module(module) = module
1016 && module == import.parent_scope.module
1017 {
1018 return Some(UnresolvedImportError {
1020 span: import.span,
1021 label: Some(String::from("cannot glob-import a module into itself")),
1022 note: None,
1023 suggestion: None,
1024 candidates: None,
1025 segment: None,
1026 module: None,
1027 });
1028 }
1029 if !is_prelude
1030 && let Some(max_vis) = max_vis.get()
1031 && !max_vis.is_at_least(import.vis, self.tcx)
1032 {
1033 let def_id = self.local_def_id(id);
1034 self.lint_buffer.buffer_lint(
1035 UNUSED_IMPORTS,
1036 id,
1037 import.span,
1038 BuiltinLintDiag::RedundantImportVisibility {
1039 max_vis: max_vis.to_string(def_id, self.tcx),
1040 import_vis: import.vis.to_string(def_id, self.tcx),
1041 span: import.span,
1042 },
1043 );
1044 }
1045 return None;
1046 }
1047 _ => unreachable!(),
1048 };
1049
1050 if self.privacy_errors.len() != privacy_errors_len {
1051 let mut path = import.module_path.clone();
1054 path.push(Segment::from_ident(ident));
1055 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) = self.resolve_path(
1056 &path,
1057 None,
1058 &import.parent_scope,
1059 Some(finalize),
1060 ignore_binding,
1061 None,
1062 ) {
1063 let res = module.res().map(|r| (r, ident));
1064 for error in &mut self.privacy_errors[privacy_errors_len..] {
1065 error.outermost_res = res;
1066 }
1067 }
1068 }
1069
1070 let mut all_ns_err = true;
1071 self.per_ns(|this, ns| {
1072 if !type_ns_only || ns == TypeNS {
1073 let binding = this.resolve_ident_in_module(
1074 module,
1075 ident,
1076 ns,
1077 &import.parent_scope,
1078 Some(Finalize { report_private: false, ..finalize }),
1079 target_bindings[ns].get(),
1080 Some(import),
1081 );
1082
1083 match binding {
1084 Ok(binding) => {
1085 let initial_res = source_bindings[ns].get().map(|initial_binding| {
1087 all_ns_err = false;
1088 if let Some(target_binding) = target_bindings[ns].get()
1089 && target.name == kw::Underscore
1090 && initial_binding.is_extern_crate()
1091 && !initial_binding.is_import()
1092 {
1093 let used = if import.module_path.is_empty() {
1094 Used::Scope
1095 } else {
1096 Used::Other
1097 };
1098 this.record_use(ident, target_binding, used);
1099 }
1100 initial_binding.res()
1101 });
1102 let res = binding.res();
1103 let has_ambiguity_error =
1104 this.ambiguity_errors.iter().any(|error| !error.warning);
1105 if res == Res::Err || has_ambiguity_error {
1106 this.dcx()
1107 .span_delayed_bug(import.span, "some error happened for an import");
1108 return;
1109 }
1110 if let Ok(initial_res) = initial_res {
1111 if res != initial_res {
1112 span_bug!(import.span, "inconsistent resolution for an import");
1113 }
1114 } else if this.privacy_errors.is_empty() {
1115 this.dcx()
1116 .create_err(CannotDetermineImportResolution { span: import.span })
1117 .emit();
1118 }
1119 }
1120 Err(..) => {
1121 }
1128 }
1129 }
1130 });
1131
1132 if all_ns_err {
1133 let mut all_ns_failed = true;
1134 self.per_ns(|this, ns| {
1135 if !type_ns_only || ns == TypeNS {
1136 let binding = this.resolve_ident_in_module(
1137 module,
1138 ident,
1139 ns,
1140 &import.parent_scope,
1141 Some(finalize),
1142 None,
1143 None,
1144 );
1145 if binding.is_ok() {
1146 all_ns_failed = false;
1147 }
1148 }
1149 });
1150
1151 return if all_ns_failed {
1152 let resolutions = match module {
1153 ModuleOrUniformRoot::Module(module) => Some(self.resolutions(module).borrow()),
1154 _ => None,
1155 };
1156 let resolutions = resolutions.as_ref().into_iter().flat_map(|r| r.iter());
1157 let names = resolutions
1158 .filter_map(|(BindingKey { ident: i, .. }, resolution)| {
1159 if i.name == ident.name {
1160 return None;
1161 } match *resolution.borrow() {
1163 NameResolution { binding: Some(name_binding), .. } => {
1164 match name_binding.kind {
1165 NameBindingKind::Import { binding, .. } => {
1166 match binding.kind {
1167 NameBindingKind::Res(Res::Err) => None,
1170 _ => Some(i.name),
1171 }
1172 }
1173 _ => Some(i.name),
1174 }
1175 }
1176 NameResolution { ref single_imports, .. }
1177 if single_imports.is_empty() =>
1178 {
1179 None
1180 }
1181 _ => Some(i.name),
1182 }
1183 })
1184 .collect::<Vec<Symbol>>();
1185
1186 let lev_suggestion =
1187 find_best_match_for_name(&names, ident.name, None).map(|suggestion| {
1188 (
1189 vec![(ident.span, suggestion.to_string())],
1190 String::from("a similar name exists in the module"),
1191 Applicability::MaybeIncorrect,
1192 )
1193 });
1194
1195 let (suggestion, note) =
1196 match self.check_for_module_export_macro(import, module, ident) {
1197 Some((suggestion, note)) => (suggestion.or(lev_suggestion), note),
1198 _ => (lev_suggestion, None),
1199 };
1200
1201 let label = match module {
1202 ModuleOrUniformRoot::Module(module) => {
1203 let module_str = module_to_string(module);
1204 if let Some(module_str) = module_str {
1205 format!("no `{ident}` in `{module_str}`")
1206 } else {
1207 format!("no `{ident}` in the root")
1208 }
1209 }
1210 _ => {
1211 if !ident.is_path_segment_keyword() {
1212 format!("no external crate `{ident}`")
1213 } else {
1214 format!("no `{ident}` in the root")
1217 }
1218 }
1219 };
1220
1221 let parent_suggestion =
1222 self.lookup_import_candidates(ident, TypeNS, &import.parent_scope, |_| true);
1223
1224 Some(UnresolvedImportError {
1225 span: import.span,
1226 label: Some(label),
1227 note,
1228 suggestion,
1229 candidates: if !parent_suggestion.is_empty() {
1230 Some(parent_suggestion)
1231 } else {
1232 None
1233 },
1234 module: import.imported_module.get().and_then(|module| {
1235 if let ModuleOrUniformRoot::Module(m) = module {
1236 m.opt_def_id()
1237 } else {
1238 None
1239 }
1240 }),
1241 segment: Some(ident.name),
1242 })
1243 } else {
1244 None
1246 };
1247 }
1248
1249 let mut reexport_error = None;
1250 let mut any_successful_reexport = false;
1251 let mut crate_private_reexport = false;
1252 self.per_ns(|this, ns| {
1253 let Ok(binding) = source_bindings[ns].get() else {
1254 return;
1255 };
1256
1257 if !binding.vis.is_at_least(import.vis, this.tcx) {
1258 reexport_error = Some((ns, binding));
1259 if let ty::Visibility::Restricted(binding_def_id) = binding.vis
1260 && binding_def_id.is_top_level_module()
1261 {
1262 crate_private_reexport = true;
1263 }
1264 } else {
1265 any_successful_reexport = true;
1266 }
1267 });
1268
1269 if !any_successful_reexport {
1271 let (ns, binding) = reexport_error.unwrap();
1272 if let Some(extern_crate_id) = pub_use_of_private_extern_crate_hack(import, binding) {
1273 self.lint_buffer.buffer_lint(
1274 PUB_USE_OF_PRIVATE_EXTERN_CRATE,
1275 import_id,
1276 import.span,
1277 BuiltinLintDiag::PrivateExternCrateReexport {
1278 source: ident,
1279 extern_crate_span: self.tcx.source_span(self.local_def_id(extern_crate_id)),
1280 },
1281 );
1282 } else if ns == TypeNS {
1283 let err = if crate_private_reexport {
1284 self.dcx()
1285 .create_err(CannotBeReexportedCratePublicNS { span: import.span, ident })
1286 } else {
1287 self.dcx().create_err(CannotBeReexportedPrivateNS { span: import.span, ident })
1288 };
1289 err.emit();
1290 } else {
1291 let mut err = if crate_private_reexport {
1292 self.dcx()
1293 .create_err(CannotBeReexportedCratePublic { span: import.span, ident })
1294 } else {
1295 self.dcx().create_err(CannotBeReexportedPrivate { span: import.span, ident })
1296 };
1297
1298 match binding.kind {
1299 NameBindingKind::Res(Res::Def(DefKind::Macro(_), def_id))
1300 if self.get_macro_by_def_id(def_id).macro_rules =>
1302 {
1303 err.subdiagnostic( ConsiderAddingMacroExport {
1304 span: binding.span,
1305 });
1306 }
1307 _ => {
1308 err.subdiagnostic( ConsiderMarkingAsPub {
1309 span: import.span,
1310 ident,
1311 });
1312 }
1313 }
1314 err.emit();
1315 }
1316 }
1317
1318 if import.module_path.len() <= 1 {
1319 let mut full_path = import.module_path.clone();
1322 full_path.push(Segment::from_ident(ident));
1323 self.per_ns(|this, ns| {
1324 if let Ok(binding) = source_bindings[ns].get() {
1325 this.lint_if_path_starts_with_module(Some(finalize), &full_path, Some(binding));
1326 }
1327 });
1328 }
1329
1330 self.per_ns(|this, ns| {
1334 if let Ok(binding) = source_bindings[ns].get() {
1335 this.import_res_map.entry(import_id).or_default()[ns] = Some(binding.res());
1336 }
1337 });
1338
1339 debug!("(resolving single import) successfully resolved import");
1340 None
1341 }
1342
1343 pub(crate) fn check_for_redundant_imports(&mut self, import: Import<'ra>) -> bool {
1344 let ImportKind::Single {
1346 source, target, ref source_bindings, ref target_bindings, id, ..
1347 } = import.kind
1348 else {
1349 unreachable!()
1350 };
1351
1352 if source != target {
1354 return false;
1355 }
1356
1357 if import.parent_scope.expansion != LocalExpnId::ROOT {
1359 return false;
1360 }
1361
1362 if self.import_use_map.get(&import) == Some(&Used::Other)
1367 || self.effective_visibilities.is_exported(self.local_def_id(id))
1368 {
1369 return false;
1370 }
1371
1372 let mut is_redundant = true;
1373 let mut redundant_span = PerNS { value_ns: None, type_ns: None, macro_ns: None };
1374 self.per_ns(|this, ns| {
1375 if is_redundant && let Ok(binding) = source_bindings[ns].get() {
1376 if binding.res() == Res::Err {
1377 return;
1378 }
1379
1380 match this.early_resolve_ident_in_lexical_scope(
1381 target,
1382 ScopeSet::All(ns),
1383 &import.parent_scope,
1384 None,
1385 false,
1386 target_bindings[ns].get(),
1387 None,
1388 ) {
1389 Ok(other_binding) => {
1390 is_redundant = binding.res() == other_binding.res()
1391 && !other_binding.is_ambiguity_recursive();
1392 if is_redundant {
1393 redundant_span[ns] =
1394 Some((other_binding.span, other_binding.is_import()));
1395 }
1396 }
1397 Err(_) => is_redundant = false,
1398 }
1399 }
1400 });
1401
1402 if is_redundant && !redundant_span.is_empty() {
1403 let mut redundant_spans: Vec<_> = redundant_span.present_items().collect();
1404 redundant_spans.sort();
1405 redundant_spans.dedup();
1406 self.lint_buffer.buffer_lint(
1407 REDUNDANT_IMPORTS,
1408 id,
1409 import.span,
1410 BuiltinLintDiag::RedundantImport(redundant_spans, source),
1411 );
1412 return true;
1413 }
1414
1415 false
1416 }
1417
1418 fn resolve_glob_import(&mut self, import: Import<'ra>) {
1419 let ImportKind::Glob { id, is_prelude, .. } = import.kind else { unreachable!() };
1421
1422 let ModuleOrUniformRoot::Module(module) = import.imported_module.get().unwrap() else {
1423 self.dcx().emit_err(CannotGlobImportAllCrates { span: import.span });
1424 return;
1425 };
1426
1427 if module.is_trait() && !self.tcx.features().import_trait_associated_functions() {
1428 feature_err(
1429 self.tcx.sess,
1430 sym::import_trait_associated_functions,
1431 import.span,
1432 "`use` associated items of traits is unstable",
1433 )
1434 .emit();
1435 }
1436
1437 if module == import.parent_scope.module {
1438 return;
1439 } else if is_prelude {
1440 self.prelude = Some(module);
1441 return;
1442 }
1443
1444 module.glob_importers.borrow_mut().push(import);
1446
1447 let bindings = self
1450 .resolutions(module)
1451 .borrow()
1452 .iter()
1453 .filter_map(|(key, resolution)| {
1454 resolution.borrow().binding().map(|binding| (*key, binding))
1455 })
1456 .collect::<Vec<_>>();
1457 for (mut key, binding) in bindings {
1458 let scope = match key.ident.span.reverse_glob_adjust(module.expansion, import.span) {
1459 Some(Some(def)) => self.expn_def_scope(def),
1460 Some(None) => import.parent_scope.module,
1461 None => continue,
1462 };
1463 if self.is_accessible_from(binding.vis, scope) {
1464 let imported_binding = self.import(binding, import);
1465 let warn_ambiguity = self
1466 .resolution(import.parent_scope.module, key)
1467 .borrow()
1468 .binding()
1469 .is_some_and(|binding| binding.warn_ambiguity_recursive());
1470 let _ = self.try_define(
1471 import.parent_scope.module,
1472 key,
1473 imported_binding,
1474 warn_ambiguity,
1475 );
1476 }
1477 }
1478
1479 self.record_partial_res(id, PartialRes::new(module.res().unwrap()));
1481 }
1482
1483 fn finalize_resolutions_in(&mut self, module: Module<'ra>) {
1486 *module.globs.borrow_mut() = Vec::new();
1488
1489 let Some(def_id) = module.opt_def_id() else { return };
1490
1491 let mut children = Vec::new();
1492
1493 module.for_each_child(self, |this, ident, _, binding| {
1494 let res = binding.res().expect_non_local();
1495 let error_ambiguity = binding.is_ambiguity_recursive() && !binding.warn_ambiguity;
1496 if res != def::Res::Err && !error_ambiguity {
1497 let mut reexport_chain = SmallVec::new();
1498 let mut next_binding = binding;
1499 while let NameBindingKind::Import { binding, import, .. } = next_binding.kind {
1500 reexport_chain.push(import.simplify(this));
1501 next_binding = binding;
1502 }
1503
1504 children.push(ModChild { ident, res, vis: binding.vis, reexport_chain });
1505 }
1506 });
1507
1508 if !children.is_empty() {
1509 self.module_children.insert(def_id.expect_local(), children);
1511 }
1512 }
1513}
1514
1515fn import_path_to_string(names: &[Ident], import_kind: &ImportKind<'_>, span: Span) -> String {
1516 let pos = names.iter().position(|p| span == p.span && p.name != kw::PathRoot);
1517 let global = !names.is_empty() && names[0].name == kw::PathRoot;
1518 if let Some(pos) = pos {
1519 let names = if global { &names[1..pos + 1] } else { &names[..pos + 1] };
1520 names_to_string(names.iter().map(|ident| ident.name))
1521 } else {
1522 let names = if global { &names[1..] } else { names };
1523 if names.is_empty() {
1524 import_kind_to_string(import_kind)
1525 } else {
1526 format!(
1527 "{}::{}",
1528 names_to_string(names.iter().map(|ident| ident.name)),
1529 import_kind_to_string(import_kind),
1530 )
1531 }
1532 }
1533}
1534
1535fn import_kind_to_string(import_kind: &ImportKind<'_>) -> String {
1536 match import_kind {
1537 ImportKind::Single { source, .. } => source.to_string(),
1538 ImportKind::Glob { .. } => "*".to_string(),
1539 ImportKind::ExternCrate { .. } => "<extern crate>".to_string(),
1540 ImportKind::MacroUse { .. } => "#[macro_use]".to_string(),
1541 ImportKind::MacroExport => "#[macro_export]".to_string(),
1542 }
1543}