1 //! A bunch of methods and structures more or less related to resolving imports.
3 use crate::diagnostics::Suggestion;
4 use crate::Determinacy::{self, *};
5 use crate::Namespace::{MacroNS, TypeNS};
6 use crate::{module_to_string, names_to_string};
7 use crate::{AmbiguityKind, BindingKey, ModuleKind, ResolutionError, Resolver, Segment};
8 use crate::{Finalize, Module, ModuleOrUniformRoot, ParentScope, PerNS, ScopeSet};
9 use crate::{NameBinding, NameBindingKind, PathResult};
11 use rustc_ast::NodeId;
12 use rustc_data_structures::fx::FxHashSet;
13 use rustc_data_structures::intern::Interned;
14 use rustc_errors::{pluralize, struct_span_err, Applicability, MultiSpan};
15 use rustc_hir::def::{self, DefKind, PartialRes};
16 use rustc_middle::metadata::ModChild;
17 use rustc_middle::span_bug;
19 use rustc_session::lint::builtin::{PUB_USE_OF_PRIVATE_EXTERN_CRATE, UNUSED_IMPORTS};
20 use rustc_session::lint::BuiltinLintDiagnostics;
21 use rustc_span::hygiene::LocalExpnId;
22 use rustc_span::lev_distance::find_best_match_for_name;
23 use rustc_span::symbol::{kw, Ident, Symbol};
31 type Res = def::Res<NodeId>;
33 /// Contains data for specific kinds of imports.
35 pub enum ImportKind<'a> {
37 /// `source` in `use prefix::source as target`.
39 /// `target` in `use prefix::source as target`.
41 /// Bindings to which `source` refers to.
42 source_bindings: PerNS<Cell<Result<&'a NameBinding<'a>, Determinacy>>>,
43 /// Bindings introduced by `target`.
44 target_bindings: PerNS<Cell<Option<&'a NameBinding<'a>>>>,
45 /// `true` for `...::{self [as target]}` imports, `false` otherwise.
47 /// Did this import result from a nested import? ie. `use foo::{bar, baz};`
49 /// Additional `NodeId`s allocated to a `ast::UseTree` for automatically generated `use` statement
50 /// (eg. implicit struct constructors)
51 additional_ids: (NodeId, NodeId),
55 max_vis: Cell<Option<ty::Visibility>>, // The visibility of the greatest re-export.
56 // n.b. `max_vis` is only used in `finalize_import` to check for re-export errors.
59 source: Option<Symbol>,
65 /// Manually implement `Debug` for `ImportKind` because the `source/target_bindings`
66 /// contain `Cell`s which can introduce infinite loops while printing.
67 impl<'a> std::fmt::Debug for ImportKind<'a> {
68 fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
77 // Ignore the following to avoid an infinite loop while printing.
81 .debug_struct("Single")
82 .field("source", source)
83 .field("target", target)
84 .field("type_ns_only", type_ns_only)
85 .field("nested", nested)
86 .field("additional_ids", additional_ids)
87 .finish_non_exhaustive(),
88 Glob { ref is_prelude, ref max_vis } => f
90 .field("is_prelude", is_prelude)
91 .field("max_vis", max_vis)
93 ExternCrate { ref source, ref target } => f
94 .debug_struct("ExternCrate")
95 .field("source", source)
96 .field("target", target)
98 MacroUse => f.debug_struct("MacroUse").finish(),
104 #[derive(Debug, Clone)]
105 pub(crate) struct Import<'a> {
106 pub kind: ImportKind<'a>,
108 /// The ID of the `extern crate`, `UseTree` etc that imported this `Import`.
110 /// In the case where the `Import` was expanded from a "nested" use tree,
111 /// this id is the ID of the leaf tree. For example:
113 /// ```ignore (pacify the merciless tidy)
114 /// use foo::bar::{a, b}
117 /// If this is the import for `foo::bar::a`, we would have the ID of the `UseTree`
118 /// for `a` in this field.
121 /// The `id` of the "root" use-kind -- this is always the same as
122 /// `id` except in the case of "nested" use trees, in which case
123 /// it will be the `id` of the root use tree. e.g., in the example
124 /// from `id`, this would be the ID of the `use foo::bar`
128 /// Span of the entire use statement.
131 /// Span of the entire use statement with attributes.
132 pub use_span_with_attributes: Span,
134 /// Did the use statement have any attributes?
135 pub has_attributes: bool,
137 /// Span of this use tree.
140 /// Span of the *root* use tree (see `root_id`).
143 pub parent_scope: ParentScope<'a>,
144 pub module_path: Vec<Segment>,
145 /// The resolution of `module_path`.
146 pub imported_module: Cell<Option<ModuleOrUniformRoot<'a>>>,
147 pub vis: Cell<Option<ty::Visibility>>,
148 pub used: Cell<bool>,
151 impl<'a> Import<'a> {
152 pub fn is_glob(&self) -> bool {
153 matches!(self.kind, ImportKind::Glob { .. })
156 pub fn is_nested(&self) -> bool {
158 ImportKind::Single { nested, .. } => nested,
163 pub(crate) fn expect_vis(&self) -> ty::Visibility {
164 self.vis.get().expect("encountered cleared import visibility")
168 /// Records information about the resolution of a name in a namespace of a module.
169 #[derive(Clone, Default, Debug)]
170 pub(crate) struct NameResolution<'a> {
171 /// Single imports that may define the name in the namespace.
172 /// Imports are arena-allocated, so it's ok to use pointers as keys.
173 pub single_imports: FxHashSet<Interned<'a, Import<'a>>>,
174 /// The least shadowable known binding for this name, or None if there are no known bindings.
175 pub binding: Option<&'a NameBinding<'a>>,
176 pub shadowed_glob: Option<&'a NameBinding<'a>>,
179 impl<'a> NameResolution<'a> {
180 // Returns the binding for the name if it is known or None if it not known.
181 pub(crate) fn binding(&self) -> Option<&'a NameBinding<'a>> {
182 self.binding.and_then(|binding| {
183 if !binding.is_glob_import() || self.single_imports.is_empty() {
191 pub(crate) fn add_single_import(&mut self, import: &'a Import<'a>) {
192 self.single_imports.insert(Interned::new_unchecked(import));
196 // Reexports of the form `pub use foo as bar;` where `foo` is `extern crate foo;`
197 // are permitted for backward-compatibility under a deprecation lint.
198 fn pub_use_of_private_extern_crate_hack(import: &Import<'_>, binding: &NameBinding<'_>) -> bool {
199 match (&import.kind, &binding.kind) {
201 ImportKind::Single { .. },
202 NameBindingKind::Import {
203 import: Import { kind: ImportKind::ExternCrate { .. }, .. },
206 ) => import.expect_vis().is_public(),
211 impl<'a> Resolver<'a> {
212 // Given a binding and an import that resolves to it,
213 // return the corresponding binding defined by the import.
214 pub(crate) fn import(
216 binding: &'a NameBinding<'a>,
217 import: &'a Import<'a>,
218 ) -> &'a NameBinding<'a> {
219 let import_vis = import.expect_vis();
220 let vis = if binding.vis.is_at_least(import_vis, self)
221 || pub_use_of_private_extern_crate_hack(import, binding)
228 if let ImportKind::Glob { ref max_vis, .. } = import.kind {
230 || max_vis.get().map_or(true, |max_vis| vis.is_at_least(max_vis, self))
232 max_vis.set(Some(vis))
236 self.arenas.alloc_name_binding(NameBinding {
237 kind: NameBindingKind::Import { binding, import, used: Cell::new(false) },
241 expansion: import.parent_scope.expansion,
245 // Define the name or return the existing binding if there is a collision.
246 pub(crate) fn try_define(
250 binding: &'a NameBinding<'a>,
251 ) -> Result<(), &'a NameBinding<'a>> {
252 let res = binding.res();
253 self.check_reserved_macro_name(key.ident, res);
254 self.set_binding_parent_module(binding, module);
255 self.update_resolution(module, key, |this, resolution| {
256 if let Some(old_binding) = resolution.binding {
258 // Do not override real bindings with `Res::Err`s from error recovery.
261 match (old_binding.is_glob_import(), binding.is_glob_import()) {
263 if res != old_binding.res() {
264 resolution.binding = Some(this.ambiguity(
265 AmbiguityKind::GlobVsGlob,
269 } else if !old_binding.vis.is_at_least(binding.vis, &*this) {
270 // We are glob-importing the same item but with greater visibility.
271 resolution.binding = Some(binding);
274 (old_glob @ true, false) | (old_glob @ false, true) => {
275 let (glob_binding, nonglob_binding) =
276 if old_glob { (old_binding, binding) } else { (binding, old_binding) };
277 if glob_binding.res() != nonglob_binding.res()
279 && nonglob_binding.expansion != LocalExpnId::ROOT
281 resolution.binding = Some(this.ambiguity(
282 AmbiguityKind::GlobVsExpanded,
287 resolution.binding = Some(nonglob_binding);
289 resolution.shadowed_glob = Some(glob_binding);
292 return Err(old_binding);
296 resolution.binding = Some(binding);
306 primary_binding: &'a NameBinding<'a>,
307 secondary_binding: &'a NameBinding<'a>,
308 ) -> &'a NameBinding<'a> {
309 self.arenas.alloc_name_binding(NameBinding {
310 ambiguity: Some((secondary_binding, kind)),
311 ..primary_binding.clone()
315 // Use `f` to mutate the resolution of the name in the module.
316 // If the resolution becomes a success, define it in the module's glob importers.
317 fn update_resolution<T, F>(&mut self, module: Module<'a>, key: BindingKey, f: F) -> T
319 F: FnOnce(&mut Resolver<'a>, &mut NameResolution<'a>) -> T,
321 // Ensure that `resolution` isn't borrowed when defining in the module's glob importers,
322 // during which the resolution might end up getting re-defined via a glob cycle.
324 let resolution = &mut *self.resolution(module, key).borrow_mut();
325 let old_binding = resolution.binding();
327 let t = f(self, resolution);
329 match resolution.binding() {
330 _ if old_binding.is_some() => return t,
332 Some(binding) => match old_binding {
333 Some(old_binding) if ptr::eq(old_binding, binding) => return t,
339 // Define `binding` in `module`s glob importers.
340 for import in module.glob_importers.borrow_mut().iter() {
341 let mut ident = key.ident;
342 let scope = match ident.span.reverse_glob_adjust(module.expansion, import.span) {
343 Some(Some(def)) => self.expn_def_scope(def),
344 Some(None) => import.parent_scope.module,
347 if self.is_accessible_from(binding.vis, scope) {
348 let imported_binding = self.import(binding, import);
349 let key = BindingKey { ident, ..key };
350 let _ = self.try_define(import.parent_scope.module, key, imported_binding);
357 // Define a dummy resolution containing a `Res::Err` as a placeholder for a failed resolution,
358 // also mark such failed imports as used to avoid duplicate diagnostics.
359 fn import_dummy_binding(&mut self, import: &'a Import<'a>) {
360 if let ImportKind::Single { target, ref target_bindings, .. } = import.kind {
361 if target_bindings.iter().any(|binding| binding.get().is_some()) {
362 return; // Has resolution, do not create the dummy binding
364 let dummy_binding = self.dummy_binding;
365 let dummy_binding = self.import(dummy_binding, import);
366 self.per_ns(|this, ns| {
367 let key = this.new_key(target, ns);
368 let _ = this.try_define(import.parent_scope.module, key, dummy_binding);
370 self.record_use(target, dummy_binding, false);
371 } else if import.imported_module.get().is_none() {
372 import.used.set(true);
373 self.used_imports.insert(import.id);
378 /// An error that may be transformed into a diagnostic later. Used to combine multiple unresolved
379 /// import errors within the same use tree into a single diagnostic.
380 #[derive(Debug, Clone)]
381 struct UnresolvedImportError {
383 label: Option<String>,
384 note: Option<String>,
385 suggestion: Option<Suggestion>,
388 pub struct ImportResolver<'a, 'b> {
389 pub r: &'a mut Resolver<'b>,
392 impl<'a, 'b> ImportResolver<'a, 'b> {
395 // This is a fixed-point algorithm. We resolve imports until our efforts
396 // are stymied by an unresolved import; then we bail out of the current
397 // module and continue. We terminate successfully once no more imports
398 // remain or unsuccessfully when no forward progress in resolving imports
401 /// Resolves all imports for the crate. This method performs the fixed-
403 pub fn resolve_imports(&mut self) {
404 let mut prev_num_indeterminates = self.r.indeterminate_imports.len() + 1;
405 while self.r.indeterminate_imports.len() < prev_num_indeterminates {
406 prev_num_indeterminates = self.r.indeterminate_imports.len();
407 for import in mem::take(&mut self.r.indeterminate_imports) {
408 match self.resolve_import(&import) {
409 true => self.r.determined_imports.push(import),
410 false => self.r.indeterminate_imports.push(import),
416 pub fn finalize_imports(&mut self) {
417 for module in self.r.arenas.local_modules().iter() {
418 self.finalize_resolutions_in(module);
421 let mut seen_spans = FxHashSet::default();
422 let mut errors = vec![];
423 let mut prev_root_id: NodeId = NodeId::from_u32(0);
424 let determined_imports = mem::take(&mut self.r.determined_imports);
425 let indeterminate_imports = mem::take(&mut self.r.indeterminate_imports);
427 for (is_indeterminate, import) in determined_imports
430 .chain(indeterminate_imports.into_iter().map(|i| (true, i)))
432 let unresolved_import_error = self.finalize_import(import);
434 // If this import is unresolved then create a dummy import
435 // resolution for it so that later resolve stages won't complain.
436 self.r.import_dummy_binding(import);
438 if let Some(err) = unresolved_import_error {
439 if let ImportKind::Single { source, ref source_bindings, .. } = import.kind {
440 if source.name == kw::SelfLower {
441 // Silence `unresolved import` error if E0429 is already emitted
442 if let Err(Determined) = source_bindings.value_ns.get() {
448 if prev_root_id.as_u32() != 0
449 && prev_root_id.as_u32() != import.root_id.as_u32()
450 && !errors.is_empty()
452 // In the case of a new import line, throw a diagnostic message
453 // for the previous line.
454 self.throw_unresolved_import_error(errors, None);
457 if seen_spans.insert(err.span) {
458 let path = import_path_to_string(
459 &import.module_path.iter().map(|seg| seg.ident).collect::<Vec<_>>(),
463 errors.push((path, err));
464 prev_root_id = import.root_id;
466 } else if is_indeterminate {
467 let path = import_path_to_string(
468 &import.module_path.iter().map(|seg| seg.ident).collect::<Vec<_>>(),
472 let err = UnresolvedImportError {
478 if path.contains("::") {
479 errors.push((path, err))
484 if !errors.is_empty() {
485 self.throw_unresolved_import_error(errors, None);
489 fn throw_unresolved_import_error(
491 errors: Vec<(String, UnresolvedImportError)>,
492 span: Option<MultiSpan>,
494 /// Upper limit on the number of `span_label` messages.
495 const MAX_LABEL_COUNT: usize = 10;
497 let (span, msg) = if errors.is_empty() {
498 (span.unwrap(), "unresolved import".to_string())
500 let span = MultiSpan::from_spans(errors.iter().map(|(_, err)| err.span).collect());
502 let paths = errors.iter().map(|(path, _)| format!("`{}`", path)).collect::<Vec<_>>();
504 let msg = format!("unresolved import{} {}", pluralize!(paths.len()), paths.join(", "),);
509 let mut diag = struct_span_err!(self.r.session, span, E0432, "{}", &msg);
511 if let Some((_, UnresolvedImportError { note: Some(note), .. })) = errors.iter().last() {
515 for (_, err) in errors.into_iter().take(MAX_LABEL_COUNT) {
516 if let Some(label) = err.label {
517 diag.span_label(err.span, label);
520 if let Some((suggestions, msg, applicability)) = err.suggestion {
521 if suggestions.is_empty() {
525 diag.multipart_suggestion(&msg, suggestions, applicability);
532 /// Attempts to resolve the given import, returning true if its resolution is determined.
533 /// If successful, the resolved bindings are written into the module.
534 fn resolve_import(&mut self, import: &'b Import<'b>) -> bool {
536 "(resolving import for module) resolving import `{}::...` in `{}`",
537 Segment::names_to_string(&import.module_path),
538 module_to_string(import.parent_scope.module).unwrap_or_else(|| "???".to_string()),
541 let module = if let Some(module) = import.imported_module.get() {
544 // For better failure detection, pretend that the import will
545 // not define any names while resolving its module path.
546 let orig_vis = import.vis.take();
548 self.r.maybe_resolve_path(&import.module_path, None, &import.parent_scope);
549 import.vis.set(orig_vis);
552 PathResult::Module(module) => module,
553 PathResult::Indeterminate => return false,
554 PathResult::NonModule(..) | PathResult::Failed { .. } => return true,
558 import.imported_module.set(Some(module));
559 let (source, target, source_bindings, target_bindings, type_ns_only) = match import.kind {
567 } => (source, target, source_bindings, target_bindings, type_ns_only),
568 ImportKind::Glob { .. } => {
569 self.resolve_glob_import(import);
575 let mut indeterminate = false;
576 self.r.per_ns(|this, ns| {
577 if !type_ns_only || ns == TypeNS {
578 if let Err(Undetermined) = source_bindings[ns].get() {
579 // For better failure detection, pretend that the import will
580 // not define any names while resolving its module path.
581 let orig_vis = import.vis.take();
582 let binding = this.resolve_ident_in_module(
586 &import.parent_scope,
590 import.vis.set(orig_vis);
591 source_bindings[ns].set(binding);
596 let parent = import.parent_scope.module;
597 match source_bindings[ns].get() {
598 Err(Undetermined) => indeterminate = true,
599 // Don't update the resolution, because it was never added.
600 Err(Determined) if target.name == kw::Underscore => {}
601 Ok(binding) if binding.is_importable() => {
602 let imported_binding = this.import(binding, import);
603 target_bindings[ns].set(Some(imported_binding));
604 this.define(parent, target, ns, imported_binding);
606 source_binding @ (Ok(..) | Err(Determined)) => {
607 if source_binding.is_ok() {
608 let msg = format!("`{}` is not directly importable", target);
609 struct_span_err!(this.session, import.span, E0253, "{}", &msg)
610 .span_label(import.span, "cannot be imported directly")
613 let key = this.new_key(target, ns);
614 this.update_resolution(parent, key, |_, resolution| {
615 resolution.single_imports.remove(&Interned::new_unchecked(import));
625 /// Performs final import resolution, consistency checks and error reporting.
627 /// Optionally returns an unresolved import error. This error is buffered and used to
628 /// consolidate multiple unresolved import errors into a single diagnostic.
629 fn finalize_import(&mut self, import: &'b Import<'b>) -> Option<UnresolvedImportError> {
630 let orig_vis = import.vis.take();
631 let ignore_binding = match &import.kind {
632 ImportKind::Single { target_bindings, .. } => target_bindings[TypeNS].get(),
635 let prev_ambiguity_errors_len = self.r.ambiguity_errors.len();
636 let finalize = Finalize::with_root_span(import.root_id, import.span, import.root_span);
637 let path_res = self.r.resolve_path(
640 &import.parent_scope,
644 let no_ambiguity = self.r.ambiguity_errors.len() == prev_ambiguity_errors_len;
645 import.vis.set(orig_vis);
646 let module = match path_res {
647 PathResult::Module(module) => {
648 // Consistency checks, analogous to `finalize_macro_resolutions`.
649 if let Some(initial_module) = import.imported_module.get() {
650 if !ModuleOrUniformRoot::same_def(module, initial_module) && no_ambiguity {
651 span_bug!(import.span, "inconsistent resolution for an import");
653 } else if self.r.privacy_errors.is_empty() {
654 let msg = "cannot determine resolution for the import";
655 let msg_note = "import resolution is stuck, try simplifying other imports";
656 self.r.session.struct_span_err(import.span, msg).note(msg_note).emit();
661 PathResult::Failed { is_error_from_last_segment: false, span, label, suggestion } => {
663 assert!(import.imported_module.get().is_none());
665 .report_error(span, ResolutionError::FailedToResolve { label, suggestion });
669 PathResult::Failed { is_error_from_last_segment: true, span, label, suggestion } => {
671 assert!(import.imported_module.get().is_none());
672 let err = match self.make_path_suggestion(
674 import.module_path.clone(),
675 &import.parent_scope,
677 Some((suggestion, note)) => UnresolvedImportError {
682 vec![(span, Segment::names_to_string(&suggestion))],
683 String::from("a similar path exists"),
684 Applicability::MaybeIncorrect,
687 None => UnresolvedImportError {
698 PathResult::NonModule(_) => {
700 assert!(import.imported_module.get().is_none());
702 // The error was already reported earlier.
705 PathResult::Indeterminate => unreachable!(),
708 let (ident, target, source_bindings, target_bindings, type_ns_only) = match import.kind {
716 } => (source, target, source_bindings, target_bindings, type_ns_only),
717 ImportKind::Glob { is_prelude, ref max_vis } => {
718 if import.module_path.len() <= 1 {
719 // HACK(eddyb) `lint_if_path_starts_with_module` needs at least
720 // 2 segments, so the `resolve_path` above won't trigger it.
721 let mut full_path = import.module_path.clone();
722 full_path.push(Segment::from_ident(Ident::empty()));
723 self.r.lint_if_path_starts_with_module(Some(finalize), &full_path, None);
726 if let ModuleOrUniformRoot::Module(module) = module {
727 if ptr::eq(module, import.parent_scope.module) {
728 // Importing a module into itself is not allowed.
729 return Some(UnresolvedImportError {
731 label: Some(String::from("cannot glob-import a module into itself")),
738 && let Some(max_vis) = max_vis.get()
739 && !max_vis.is_at_least(import.expect_vis(), &*self.r)
741 let msg = "glob import doesn't reexport anything because no candidate is public enough";
742 self.r.lint_buffer.buffer_lint(UNUSED_IMPORTS, import.id, import.span, msg);
749 let mut all_ns_err = true;
750 self.r.per_ns(|this, ns| {
751 if !type_ns_only || ns == TypeNS {
752 let orig_vis = import.vis.take();
753 let binding = this.resolve_ident_in_module(
757 &import.parent_scope,
758 Some(Finalize { report_private: false, ..finalize }),
759 target_bindings[ns].get(),
761 import.vis.set(orig_vis);
765 // Consistency checks, analogous to `finalize_macro_resolutions`.
766 let initial_res = source_bindings[ns].get().map(|initial_binding| {
768 if let Some(target_binding) = target_bindings[ns].get() {
769 if target.name == kw::Underscore
770 && initial_binding.is_extern_crate()
771 && !initial_binding.is_import()
776 import.module_path.is_empty(),
780 initial_binding.res()
782 let res = binding.res();
783 if let Ok(initial_res) = initial_res {
784 if res != initial_res && this.ambiguity_errors.is_empty() {
785 span_bug!(import.span, "inconsistent resolution for an import");
787 } else if res != Res::Err
788 && this.ambiguity_errors.is_empty()
789 && this.privacy_errors.is_empty()
791 let msg = "cannot determine resolution for the import";
793 "import resolution is stuck, try simplifying other imports";
794 this.session.struct_span_err(import.span, msg).note(msg_note).emit();
798 // FIXME: This assert may fire if public glob is later shadowed by a private
799 // single import (see test `issue-55884-2.rs`). In theory single imports should
800 // always block globs, even if they are not yet resolved, so that this kind of
801 // self-inconsistent resolution never happens.
802 // Re-enable the assert when the issue is fixed.
803 // assert!(result[ns].get().is_err());
810 let mut all_ns_failed = true;
811 self.r.per_ns(|this, ns| {
812 if !type_ns_only || ns == TypeNS {
813 let binding = this.resolve_ident_in_module(
817 &import.parent_scope,
822 all_ns_failed = false;
827 return if all_ns_failed {
828 let resolutions = match module {
829 ModuleOrUniformRoot::Module(module) => {
830 Some(self.r.resolutions(module).borrow())
834 let resolutions = resolutions.as_ref().into_iter().flat_map(|r| r.iter());
835 let names = resolutions
836 .filter_map(|(BindingKey { ident: i, .. }, resolution)| {
839 } // Never suggest the same name
840 match *resolution.borrow() {
841 NameResolution { binding: Some(name_binding), .. } => {
842 match name_binding.kind {
843 NameBindingKind::Import { binding, .. } => {
845 // Never suggest the name that has binding error
846 // i.e., the name that cannot be previously resolved
847 NameBindingKind::Res(Res::Err, _) => None,
854 NameResolution { ref single_imports, .. }
855 if single_imports.is_empty() =>
862 .collect::<Vec<Symbol>>();
865 find_best_match_for_name(&names, ident.name, None).map(|suggestion| {
867 vec![(ident.span, suggestion.to_string())],
868 String::from("a similar name exists in the module"),
869 Applicability::MaybeIncorrect,
873 let (suggestion, note) =
874 match self.check_for_module_export_macro(import, module, ident) {
875 Some((suggestion, note)) => (suggestion.or(lev_suggestion), note),
876 _ => (lev_suggestion, None),
879 let label = match module {
880 ModuleOrUniformRoot::Module(module) => {
881 let module_str = module_to_string(module);
882 if let Some(module_str) = module_str {
883 format!("no `{}` in `{}`", ident, module_str)
885 format!("no `{}` in the root", ident)
889 if !ident.is_path_segment_keyword() {
890 format!("no external crate `{}`", ident)
892 // HACK(eddyb) this shows up for `self` & `super`, which
893 // should work instead - for now keep the same error message.
894 format!("no `{}` in the root", ident)
899 Some(UnresolvedImportError {
906 // `resolve_ident_in_module` reported a privacy error.
911 let mut reexport_error = None;
912 let mut any_successful_reexport = false;
913 let mut crate_private_reexport = false;
914 self.r.per_ns(|this, ns| {
915 if let Ok(binding) = source_bindings[ns].get() {
916 if !binding.vis.is_at_least(import.expect_vis(), &*this) {
917 reexport_error = Some((ns, binding));
918 if let ty::Visibility::Restricted(binding_def_id) = binding.vis {
919 if binding_def_id.is_top_level_module() {
920 crate_private_reexport = true;
924 any_successful_reexport = true;
929 // All namespaces must be re-exported with extra visibility for an error to occur.
930 if !any_successful_reexport {
931 let (ns, binding) = reexport_error.unwrap();
932 if pub_use_of_private_extern_crate_hack(import, binding) {
934 "extern crate `{}` is private, and cannot be \
935 re-exported (error E0365), consider declaring with \
939 self.r.lint_buffer.buffer_lint(
940 PUB_USE_OF_PRIVATE_EXTERN_CRATE,
946 let error_msg = if crate_private_reexport {
948 "`{}` is only public within the crate, and cannot be re-exported outside",
952 format!("`{}` is private, and cannot be re-exported", ident)
956 let label_msg = if crate_private_reexport {
957 format!("re-export of crate public `{}`", ident)
959 format!("re-export of private `{}`", ident)
962 struct_span_err!(self.r.session, import.span, E0365, "{}", error_msg)
963 .span_label(import.span, label_msg)
964 .note(&format!("consider declaring type or module `{}` with `pub`", ident))
968 struct_span_err!(self.r.session, import.span, E0364, "{error_msg}");
970 NameBindingKind::Res(Res::Def(DefKind::Macro(_), def_id), _)
971 // exclude decl_macro
972 if self.r.get_macro_by_def_id(def_id).macro_rules =>
976 "consider adding a `#[macro_export]` to the macro in the imported module",
983 "consider marking `{ident}` as `pub` in the imported module"
993 if import.module_path.len() <= 1 {
994 // HACK(eddyb) `lint_if_path_starts_with_module` needs at least
995 // 2 segments, so the `resolve_path` above won't trigger it.
996 let mut full_path = import.module_path.clone();
997 full_path.push(Segment::from_ident(ident));
998 self.r.per_ns(|this, ns| {
999 if let Ok(binding) = source_bindings[ns].get() {
1000 this.lint_if_path_starts_with_module(Some(finalize), &full_path, Some(binding));
1005 // Record what this import resolves to for later uses in documentation,
1006 // this may resolve to either a value or a type, but for documentation
1007 // purposes it's good enough to just favor one over the other.
1008 self.r.per_ns(|this, ns| {
1009 if let Ok(binding) = source_bindings[ns].get() {
1010 this.import_res_map.entry(import.id).or_default()[ns] = Some(binding.res());
1014 self.check_for_redundant_imports(ident, import, source_bindings, target_bindings, target);
1016 debug!("(resolving single import) successfully resolved import");
1020 fn check_for_redundant_imports(
1023 import: &'b Import<'b>,
1024 source_bindings: &PerNS<Cell<Result<&'b NameBinding<'b>, Determinacy>>>,
1025 target_bindings: &PerNS<Cell<Option<&'b NameBinding<'b>>>>,
1028 // Skip if the import was produced by a macro.
1029 if import.parent_scope.expansion != LocalExpnId::ROOT {
1033 // Skip if we are inside a named module (in contrast to an anonymous
1034 // module defined by a block).
1035 if let ModuleKind::Def(..) = import.parent_scope.module.kind {
1039 let mut is_redundant = PerNS { value_ns: None, type_ns: None, macro_ns: None };
1041 let mut redundant_span = PerNS { value_ns: None, type_ns: None, macro_ns: None };
1043 self.r.per_ns(|this, ns| {
1044 if let Ok(binding) = source_bindings[ns].get() {
1045 if binding.res() == Res::Err {
1049 match this.early_resolve_ident_in_lexical_scope(
1051 ScopeSet::All(ns, false),
1052 &import.parent_scope,
1055 target_bindings[ns].get(),
1057 Ok(other_binding) => {
1058 is_redundant[ns] = Some(
1059 binding.res() == other_binding.res() && !other_binding.is_ambiguity(),
1061 redundant_span[ns] = Some((other_binding.span, other_binding.is_import()));
1063 Err(_) => is_redundant[ns] = Some(false),
1068 if !is_redundant.is_empty() && is_redundant.present_items().all(|is_redundant| is_redundant)
1070 let mut redundant_spans: Vec<_> = redundant_span.present_items().collect();
1071 redundant_spans.sort();
1072 redundant_spans.dedup();
1073 self.r.lint_buffer.buffer_lint_with_diagnostic(
1077 &format!("the item `{}` is imported redundantly", ident),
1078 BuiltinLintDiagnostics::RedundantImport(redundant_spans, ident),
1083 fn resolve_glob_import(&mut self, import: &'b Import<'b>) {
1084 let ModuleOrUniformRoot::Module(module) = import.imported_module.get().unwrap() else {
1085 self.r.session.span_err(import.span, "cannot glob-import all possible crates");
1089 if module.is_trait() {
1090 self.r.session.span_err(import.span, "items in traits are not importable");
1092 } else if ptr::eq(module, import.parent_scope.module) {
1094 } else if let ImportKind::Glob { is_prelude: true, .. } = import.kind {
1095 self.r.prelude = Some(module);
1099 // Add to module's glob_importers
1100 module.glob_importers.borrow_mut().push(import);
1102 // Ensure that `resolutions` isn't borrowed during `try_define`,
1103 // since it might get updated via a glob cycle.
1106 .resolutions(module)
1109 .filter_map(|(key, resolution)| {
1110 resolution.borrow().binding().map(|binding| (*key, binding))
1112 .collect::<Vec<_>>();
1113 for (mut key, binding) in bindings {
1114 let scope = match key.ident.span.reverse_glob_adjust(module.expansion, import.span) {
1115 Some(Some(def)) => self.r.expn_def_scope(def),
1116 Some(None) => import.parent_scope.module,
1119 if self.r.is_accessible_from(binding.vis, scope) {
1120 let imported_binding = self.r.import(binding, import);
1121 let _ = self.r.try_define(import.parent_scope.module, key, imported_binding);
1125 // Record the destination of this import
1126 self.r.record_partial_res(import.id, PartialRes::new(module.res().unwrap()));
1129 // Miscellaneous post-processing, including recording re-exports,
1130 // reporting conflicts, and reporting unresolved imports.
1131 fn finalize_resolutions_in(&mut self, module: Module<'b>) {
1132 // Since import resolution is finished, globs will not define any more names.
1133 *module.globs.borrow_mut() = Vec::new();
1135 if let Some(def_id) = module.opt_def_id() {
1136 let mut reexports = Vec::new();
1138 module.for_each_child(self.r, |_, ident, _, binding| {
1139 // FIXME: Consider changing the binding inserted by `#[macro_export] macro_rules`
1140 // into the crate root to actual `NameBindingKind::Import`.
1141 if binding.is_import()
1142 || matches!(binding.kind, NameBindingKind::Res(_, _is_macro_export @ true))
1144 let res = binding.res().expect_non_local();
1145 // Ambiguous imports are treated as errors at this point and are
1146 // not exposed to other crates (see #36837 for more details).
1147 if res != def::Res::Err && !binding.is_ambiguity() {
1148 reexports.push(ModChild {
1159 if !reexports.is_empty() {
1160 // Call to `expect_local` should be fine because current
1161 // code is only called for local modules.
1162 self.r.reexport_map.insert(def_id.expect_local(), reexports);
1168 fn import_path_to_string(names: &[Ident], import_kind: &ImportKind<'_>, span: Span) -> String {
1169 let pos = names.iter().position(|p| span == p.span && p.name != kw::PathRoot);
1170 let global = !names.is_empty() && names[0].name == kw::PathRoot;
1171 if let Some(pos) = pos {
1172 let names = if global { &names[1..pos + 1] } else { &names[..pos + 1] };
1173 names_to_string(&names.iter().map(|ident| ident.name).collect::<Vec<_>>())
1175 let names = if global { &names[1..] } else { names };
1176 if names.is_empty() {
1177 import_kind_to_string(import_kind)
1181 names_to_string(&names.iter().map(|ident| ident.name).collect::<Vec<_>>()),
1182 import_kind_to_string(import_kind),
1188 fn import_kind_to_string(import_kind: &ImportKind<'_>) -> String {
1190 ImportKind::Single { source, .. } => source.to_string(),
1191 ImportKind::Glob { .. } => "*".to_string(),
1192 ImportKind::ExternCrate { .. } => "<extern crate>".to_string(),
1193 ImportKind::MacroUse => "#[macro_use]".to_string(),