1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 use self::ImportDirectiveSubclass::*;
16 use Namespace::{self, TypeNS, ValueNS};
21 use UseLexicalScopeFlag;
22 use {names_to_string, module_to_string};
23 use {resolve_error, ResolutionError};
25 use build_reduced_graph;
28 use rustc::middle::def::*;
29 use rustc::middle::def_id::DefId;
30 use rustc::middle::privacy::*;
32 use syntax::ast::{NodeId, Name};
33 use syntax::attr::AttrMetaMethods;
34 use syntax::codemap::Span;
35 use syntax::util::lev_distance::find_best_match_for_name;
37 use std::mem::replace;
39 /// Contains data for specific types of import directives.
40 #[derive(Copy, Clone,Debug)]
41 pub enum ImportDirectiveSubclass {
42 SingleImport(Name /* target */, Name /* source */),
46 /// Whether an import can be shadowed by another import.
47 #[derive(Debug,PartialEq,Clone,Copy)]
53 /// One import directive.
54 #[derive(Debug,Clone)]
55 pub struct ImportDirective {
56 pub module_path: Vec<Name>,
57 pub subclass: ImportDirectiveSubclass,
60 pub is_public: bool, // see note in ImportResolutionPerNamespace about how to use this
61 pub shadowable: Shadowable,
64 impl ImportDirective {
65 pub fn new(module_path: Vec<Name>,
66 subclass: ImportDirectiveSubclass,
70 shadowable: Shadowable)
73 module_path: module_path,
78 shadowable: shadowable,
83 /// The item that an import resolves to.
84 #[derive(Clone,Debug)]
85 pub struct Target<'a> {
86 pub target_module: Module<'a>,
87 pub binding: NameBinding<'a>,
88 pub shadowable: Shadowable,
92 pub fn new(target_module: Module<'a>, binding: NameBinding<'a>, shadowable: Shadowable)
95 target_module: target_module,
97 shadowable: shadowable,
103 /// An ImportResolution records what we know about an imported name in a given namespace.
104 /// More specifically, it records the number of unresolved `use` directives that import the name,
105 /// the `use` directive importing the name in the namespace, and the `NameBinding` to which the
106 /// name in the namespace resolves (if applicable).
107 /// Different `use` directives may import the same name in different namespaces.
108 pub struct ImportResolution<'a> {
109 // When outstanding_references reaches zero, outside modules can count on the targets being
110 // correct. Before then, all bets are off; future `use` directives could override the name.
111 // Since shadowing is forbidden, the only way outstanding_references > 1 in a legal program
112 // is if the name is imported by exactly two `use` directives, one of which resolves to a
113 // value and the other of which resolves to a type.
114 pub outstanding_references: usize,
116 /// Whether this resolution came from a `use` or a `pub use`.
119 /// Resolution of the name in the namespace
120 pub target: Option<Target<'a>>,
122 /// The source node of the `use` directive
126 impl<'a> ImportResolution<'a> {
127 pub fn new(id: NodeId, is_public: bool) -> Self {
129 outstanding_references: 0,
132 is_public: is_public,
136 pub fn shadowable(&self) -> Shadowable {
138 Some(ref target) => target.shadowable,
139 None => Shadowable::Always,
144 struct ImportResolvingError<'a> {
145 /// Module where the error happened
146 source_module: Module<'a>,
147 import_directive: ImportDirective,
152 struct ImportResolver<'a, 'b: 'a, 'tcx: 'b> {
153 resolver: &'a mut Resolver<'b, 'tcx>,
156 impl<'a, 'b:'a, 'tcx:'b> ImportResolver<'a, 'b, 'tcx> {
159 // This is a fixed-point algorithm. We resolve imports until our efforts
160 // are stymied by an unresolved import; then we bail out of the current
161 // module and continue. We terminate successfully once no more imports
162 // remain or unsuccessfully when no forward progress in resolving imports
165 /// Resolves all imports for the crate. This method performs the fixed-
167 fn resolve_imports(&mut self) {
169 let mut prev_unresolved_imports = 0;
171 debug!("(resolving imports) iteration {}, {} imports left",
173 self.resolver.unresolved_imports);
175 let module_root = self.resolver.graph_root;
176 let errors = self.resolve_imports_for_module_subtree(module_root);
178 if self.resolver.unresolved_imports == 0 {
179 debug!("(resolving imports) success");
183 if self.resolver.unresolved_imports == prev_unresolved_imports {
185 if errors.len() > 0 {
187 self.import_resolving_error(e)
190 // Report unresolved imports only if no hard error was already reported
191 // to avoid generating multiple errors on the same import.
192 // Imports that are still indeterminate at this point are actually blocked
193 // by errored imports, so there is no point reporting them.
194 self.resolver.report_unresolved_imports(module_root);
200 prev_unresolved_imports = self.resolver.unresolved_imports;
204 /// Resolves an `ImportResolvingError` into the correct enum discriminant
205 /// and passes that on to `resolve_error`.
206 fn import_resolving_error(&self, e: ImportResolvingError) {
207 // If it's a single failed import then create a "fake" import
208 // resolution for it so that later resolve stages won't complain.
209 if let SingleImport(target, _) = e.import_directive.subclass {
210 let mut import_resolutions = e.source_module.import_resolutions.borrow_mut();
212 let resolution = import_resolutions.entry((target, ValueNS)).or_insert_with(|| {
213 debug!("(resolving import error) adding import resolution for `{}`",
216 ImportResolution::new(e.import_directive.id,
217 e.import_directive.is_public)
220 if resolution.target.is_none() {
221 debug!("(resolving import error) adding fake target to import resolution of `{}`",
224 let name_binding = NameBinding {
225 modifiers: DefModifiers::IMPORTABLE,
226 def_or_module: DefOrModule::Def(Def::Err),
230 // Create a fake target pointing to a fake name binding in our
232 let target = Target::new(e.source_module,
236 resolution.target = Some(target);
240 let path = import_path_to_string(&e.import_directive.module_path,
241 e.import_directive.subclass);
243 resolve_error(self.resolver,
245 ResolutionError::UnresolvedImport(Some((&path, &e.help))));
248 /// Attempts to resolve imports for the given module and all of its
250 fn resolve_imports_for_module_subtree(&mut self,
252 -> Vec<ImportResolvingError<'b>> {
253 let mut errors = Vec::new();
254 debug!("(resolving imports for module subtree) resolving {}",
255 module_to_string(&*module_));
256 let orig_module = replace(&mut self.resolver.current_module, module_);
257 errors.extend(self.resolve_imports_for_module(module_));
258 self.resolver.current_module = orig_module;
260 build_reduced_graph::populate_module_if_necessary(self.resolver, &module_);
261 module_.for_each_local_child(|_, _, child_node| {
262 match child_node.module() {
266 Some(child_module) => {
267 errors.extend(self.resolve_imports_for_module_subtree(child_module));
272 for (_, child_module) in module_.anonymous_children.borrow().iter() {
273 errors.extend(self.resolve_imports_for_module_subtree(child_module));
279 /// Attempts to resolve imports for the given module only.
280 fn resolve_imports_for_module(&mut self, module: Module<'b>) -> Vec<ImportResolvingError<'b>> {
281 let mut errors = Vec::new();
283 if module.all_imports_resolved() {
284 debug!("(resolving imports for module) all imports resolved for {}",
285 module_to_string(&*module));
289 let mut imports = module.imports.borrow_mut();
290 let import_count = imports.len();
291 let mut indeterminate_imports = Vec::new();
292 while module.resolved_import_count.get() + indeterminate_imports.len() < import_count {
293 let import_index = module.resolved_import_count.get();
294 match self.resolve_import_for_module(module, &imports[import_index]) {
295 ResolveResult::Failed(err) => {
296 let import_directive = &imports[import_index];
297 let (span, help) = match err {
298 Some((span, msg)) => (span, format!(". {}", msg)),
299 None => (import_directive.span, String::new()),
301 errors.push(ImportResolvingError {
302 source_module: module,
303 import_directive: import_directive.clone(),
308 ResolveResult::Indeterminate => {}
309 ResolveResult::Success(()) => {
311 module.resolved_import_count
312 .set(module.resolved_import_count.get() + 1);
316 // This resolution was not successful, keep it for later
317 indeterminate_imports.push(imports.swap_remove(import_index));
321 imports.extend(indeterminate_imports);
326 /// Attempts to resolve the given import. The return value indicates
327 /// failure if we're certain the name does not exist, indeterminate if we
328 /// don't know whether the name exists at the moment due to other
329 /// currently-unresolved imports, or success if we know the name exists.
330 /// If successful, the resolved bindings are written into the module.
331 fn resolve_import_for_module(&mut self,
333 import_directive: &ImportDirective)
334 -> ResolveResult<()> {
335 let mut resolution_result = ResolveResult::Failed(None);
336 let module_path = &import_directive.module_path;
338 debug!("(resolving import for module) resolving import `{}::...` in `{}`",
339 names_to_string(&module_path[..]),
340 module_to_string(&*module_));
342 // First, resolve the module path for the directive, if necessary.
343 let container = if module_path.is_empty() {
344 // Use the crate root.
345 Some((self.resolver.graph_root, LastMod(AllPublic)))
347 match self.resolver.resolve_module_path(module_,
349 UseLexicalScopeFlag::DontUseLexicalScope,
350 import_directive.span) {
351 ResolveResult::Failed(err) => {
352 resolution_result = ResolveResult::Failed(err);
355 ResolveResult::Indeterminate => {
356 resolution_result = ResolveResult::Indeterminate;
359 ResolveResult::Success(container) => Some(container),
365 Some((containing_module, lp)) => {
366 // We found the module that the target is contained
367 // within. Attempt to resolve the import within it.
369 match import_directive.subclass {
370 SingleImport(target, source) => {
371 resolution_result = self.resolve_single_import(&module_,
379 resolution_result = self.resolve_glob_import(&module_,
388 // Decrement the count of unresolved imports.
389 match resolution_result {
390 ResolveResult::Success(()) => {
391 assert!(self.resolver.unresolved_imports >= 1);
392 self.resolver.unresolved_imports -= 1;
395 // Nothing to do here; just return the error.
399 // Decrement the count of unresolved globs if necessary. But only if
400 // the resolution result is a success -- other cases will
401 // be handled by the main loop.
403 if resolution_result.success() {
404 match import_directive.subclass {
406 module_.dec_glob_count();
407 if import_directive.is_public {
408 module_.dec_pub_glob_count();
411 SingleImport(..) => {
415 if import_directive.is_public {
416 module_.dec_pub_count();
420 return resolution_result;
423 /// Resolves the name in the namespace of the module because it is being imported by
424 /// importing_module. Returns the module in which the name was defined (as opposed to imported),
425 /// the name bindings defining the name, and whether or not the name was imported into `module`.
426 fn resolve_name_in_module(&mut self,
427 module: Module<'b>, // Module containing the name
430 importing_module: Module<'b>) // Module importing the name
431 -> (ResolveResult<(Module<'b>, NameBinding<'b>)>, bool) {
432 build_reduced_graph::populate_module_if_necessary(self.resolver, module);
433 if let Some(name_binding) = module.get_child(name, ns) {
434 if name_binding.is_extern_crate() {
435 // track the extern crate as used.
436 if let Some(DefId { krate, .. }) = name_binding.module().unwrap().def_id() {
437 self.resolver.used_crates.insert(krate);
440 return (Success((module, name_binding)), false)
443 // If there is an unresolved glob at this point in the containing module, bail out.
444 // We don't know enough to be able to resolve the name.
445 if module.pub_glob_count.get() > 0 {
446 return (Indeterminate, false);
449 match module.import_resolutions.borrow().get(&(name, ns)) {
450 // The containing module definitely doesn't have an exported import with the
451 // name in question. We can therefore accurately report that names are unbound.
452 None => (Failed(None), false),
454 // The name is an import which has been fully resolved, so we just follow it.
455 Some(resolution) if resolution.outstanding_references == 0 => {
456 // Import resolutions must be declared with "pub" in order to be exported.
457 if !resolution.is_public {
458 return (Failed(None), false);
461 let target = resolution.target.clone();
462 if let Some(Target { target_module, binding, shadowable: _ }) = target {
463 // track used imports and extern crates as well
464 self.resolver.used_imports.insert((resolution.id, ns));
465 self.resolver.record_import_use(resolution.id, name);
466 if let Some(DefId { krate, .. }) = target_module.def_id() {
467 self.resolver.used_crates.insert(krate);
469 (Success((target_module, binding)), true)
471 (Failed(None), false)
475 // If module is the same module whose import we are resolving and
476 // it has an unresolved import with the same name as `name`, then the user
477 // is actually trying to import an item that is declared in the same scope
480 // use self::submodule;
481 // pub mod submodule;
483 // In this case we continue as if we resolved the import and let
484 // check_for_conflicts_between_imports_and_items handle the conflict
485 Some(_) => match (importing_module.def_id(), module.def_id()) {
486 (Some(id1), Some(id2)) if id1 == id2 => (Failed(None), false),
487 _ => (Indeterminate, false)
492 fn resolve_single_import(&mut self,
494 target_module: Module<'b>,
497 directive: &ImportDirective,
499 -> ResolveResult<()> {
500 debug!("(resolving single import) resolving `{}` = `{}::{}` from `{}` id {}, last \
503 module_to_string(&*target_module),
505 module_to_string(module_),
514 .span_bug(directive.span, "not expecting Import here, must be LastMod")
518 // We need to resolve both namespaces for this to succeed.
519 let (value_result, value_used_reexport) =
520 self.resolve_name_in_module(&target_module, source, ValueNS, module_);
521 let (type_result, type_used_reexport) =
522 self.resolve_name_in_module(&target_module, source, TypeNS, module_);
524 match (&value_result, &type_result) {
525 (&Success((_, ref name_binding)), _) if !value_used_reexport &&
526 directive.is_public &&
527 !name_binding.is_public() => {
528 let msg = format!("`{}` is private, and cannot be reexported", source);
529 let note_msg = format!("Consider marking `{}` as `pub` in the imported module",
531 struct_span_err!(self.resolver.session, directive.span, E0364, "{}", &msg)
532 .span_note(directive.span, ¬e_msg)
536 (_, &Success((_, ref name_binding))) if !type_used_reexport &&
537 directive.is_public => {
538 if !name_binding.is_public() {
539 let msg = format!("`{}` is private, and cannot be reexported", source);
541 format!("Consider declaring type or module `{}` with `pub`", source);
542 struct_span_err!(self.resolver.session, directive.span, E0365, "{}", &msg)
543 .span_note(directive.span, ¬e_msg)
545 } else if name_binding.defined_with(DefModifiers::PRIVATE_VARIANT) {
546 let msg = format!("variant `{}` is private, and cannot be reexported \
547 (error E0364), consider declaring its enum as `pub`",
549 self.resolver.session.add_lint(lint::builtin::PRIVATE_IN_PUBLIC,
559 let mut lev_suggestion = "".to_owned();
560 match (&value_result, &type_result) {
561 (&Indeterminate, _) | (_, &Indeterminate) => return Indeterminate,
562 (&Failed(_), &Failed(_)) => {
563 let children = target_module.children.borrow();
564 let names = children.keys().map(|&(ref name, _)| name);
565 if let Some(name) = find_best_match_for_name(names, &source.as_str(), None) {
566 lev_suggestion = format!(". Did you mean to use `{}`?", name);
568 let resolutions = target_module.import_resolutions.borrow();
569 let names = resolutions.keys().map(|&(ref name, _)| name);
570 if let Some(name) = find_best_match_for_name(names,
574 format!(". Did you mean to use the re-exported import `{}`?", name);
581 let mut value_used_public = false;
582 let mut type_used_public = false;
584 // We've successfully resolved the import. Write the results in.
585 let mut import_resolutions = module_.import_resolutions.borrow_mut();
588 let mut check_and_write_import = |namespace, result, used_public: &mut bool| {
589 let result: &ResolveResult<(Module<'b>, NameBinding)> = result;
591 let import_resolution = import_resolutions.get_mut(&(target, namespace)).unwrap();
592 let namespace_name = match namespace {
598 Success((ref target_module, ref name_binding)) => {
599 debug!("(resolving single import) found {:?} target: {:?}",
602 self.check_for_conflicting_import(&import_resolution,
607 self.check_that_import_is_importable(&name_binding,
611 import_resolution.target = Some(Target::new(target_module,
612 name_binding.clone(),
613 directive.shadowable));
614 import_resolution.id = directive.id;
615 import_resolution.is_public = directive.is_public;
617 self.add_export(module_, target, &import_resolution);
618 *used_public = name_binding.is_public();
624 panic!("{:?} result should be known at this point", namespace_name);
628 self.check_for_conflicts_between_imports_and_items(module_,
631 (target, namespace));
633 check_and_write_import(ValueNS, &value_result, &mut value_used_public);
634 check_and_write_import(TypeNS, &type_result, &mut type_used_public);
637 if let (&Failed(_), &Failed(_)) = (&value_result, &type_result) {
638 let msg = format!("There is no `{}` in `{}`{}",
640 module_to_string(&target_module), lev_suggestion);
641 return Failed(Some((directive.span, msg)));
644 let value_used_public = value_used_reexport || value_used_public;
645 let type_used_public = type_used_reexport || type_used_public;
647 let value_def_and_priv = {
648 let import_resolution_value = import_resolutions.get_mut(&(target, ValueNS)).unwrap();
649 assert!(import_resolution_value.outstanding_references >= 1);
650 import_resolution_value.outstanding_references -= 1;
652 // Record what this import resolves to for later uses in documentation,
653 // this may resolve to either a value or a type, but for documentation
654 // purposes it's good enough to just favor one over the other.
655 import_resolution_value.target.as_ref().map(|target| {
656 let def = target.binding.def().unwrap();
657 let last_private = if value_used_public { lp } else { DependsOn(def.def_id()) };
662 let type_def_and_priv = {
663 let import_resolution_type = import_resolutions.get_mut(&(target, TypeNS)).unwrap();
664 assert!(import_resolution_type.outstanding_references >= 1);
665 import_resolution_type.outstanding_references -= 1;
667 import_resolution_type.target.as_ref().map(|target| {
668 let def = target.binding.def().unwrap();
669 let last_private = if type_used_public { lp } else { DependsOn(def.def_id()) };
674 let import_lp = LastImport {
675 value_priv: value_def_and_priv.map(|(_, p)| p),
677 type_priv: type_def_and_priv.map(|(_, p)| p),
681 if let Some((def, _)) = value_def_and_priv {
682 self.resolver.def_map.borrow_mut().insert(directive.id,
685 last_private: import_lp,
689 if let Some((def, _)) = type_def_and_priv {
690 self.resolver.def_map.borrow_mut().insert(directive.id,
693 last_private: import_lp,
698 debug!("(resolving single import) successfully resolved import");
702 // Resolves a glob import. Note that this function cannot fail; it either
703 // succeeds or bails out (as importing * from an empty module or a module
704 // that exports nothing is valid). target_module is the module we are
705 // actually importing, i.e., `foo` in `use foo::*`.
706 fn resolve_glob_import(&mut self,
708 target_module: Module<'b>,
709 import_directive: &ImportDirective,
711 -> ResolveResult<()> {
712 let id = import_directive.id;
713 let is_public = import_directive.is_public;
715 // This function works in a highly imperative manner; it eagerly adds
716 // everything it can to the list of import resolutions of the module
718 debug!("(resolving glob import) resolving glob import {}", id);
720 // We must bail out if the node has unresolved imports of any kind
721 // (including globs).
722 if (*target_module).pub_count.get() > 0 {
723 debug!("(resolving glob import) target module has unresolved pub imports; bailing out");
724 return ResolveResult::Indeterminate;
727 // Add all resolved imports from the containing module.
728 let import_resolutions = target_module.import_resolutions.borrow();
730 if module_.import_resolutions.borrow_state() != ::std::cell::BorrowState::Unused {
731 // In this case, target_module == module_
732 // This means we are trying to glob import a module into itself,
734 debug!("(resolving glob imports) target module is current module; giving up");
735 return ResolveResult::Failed(Some((import_directive.span,
736 "Cannot glob-import a module into itself.".into())));
739 for (&(name, ns), target_import_resolution) in import_resolutions.iter() {
740 debug!("(resolving glob import) writing module resolution {} into `{}`",
742 module_to_string(module_));
744 // Here we merge two import resolutions.
745 let mut import_resolutions = module_.import_resolutions.borrow_mut();
746 let mut dest_import_resolution =
747 import_resolutions.entry((name, ns))
748 .or_insert_with(|| ImportResolution::new(id, is_public));
750 match target_import_resolution.target {
751 Some(ref target) if target_import_resolution.is_public => {
752 self.check_for_conflicting_import(&dest_import_resolution,
753 import_directive.span,
756 dest_import_resolution.id = id;
757 dest_import_resolution.is_public = is_public;
758 dest_import_resolution.target = Some(target.clone());
759 self.add_export(module_, name, &dest_import_resolution);
765 // Add all children from the containing module.
766 build_reduced_graph::populate_module_if_necessary(self.resolver, &target_module);
768 target_module.for_each_local_child(|name, ns, name_binding| {
769 self.merge_import_resolution(module_,
773 name_binding.clone());
776 // Record the destination of this import
777 if let Some(did) = target_module.def_id() {
778 self.resolver.def_map.borrow_mut().insert(id,
780 base_def: Def::Mod(did),
786 debug!("(resolving glob import) successfully resolved import");
787 return ResolveResult::Success(());
790 fn merge_import_resolution(&mut self,
792 containing_module: Module<'b>,
793 import_directive: &ImportDirective,
794 (name, ns): (Name, Namespace),
795 name_binding: NameBinding<'b>) {
796 let id = import_directive.id;
797 let is_public = import_directive.is_public;
799 let mut import_resolutions = module_.import_resolutions.borrow_mut();
800 let dest_import_resolution = import_resolutions.entry((name, ns)).or_insert_with(|| {
801 ImportResolution::new(id, is_public)
804 debug!("(resolving glob import) writing resolution `{}` in `{}` to `{}`",
806 module_to_string(&*containing_module),
807 module_to_string(module_));
809 // Merge the child item into the import resolution.
810 let modifier = DefModifiers::IMPORTABLE | DefModifiers::PUBLIC;
812 if ns == TypeNS && is_public && name_binding.defined_with(DefModifiers::PRIVATE_VARIANT) {
813 let msg = format!("variant `{}` is private, and cannot be reexported (error \
814 E0364), consider declaring its enum as `pub`", name);
815 self.resolver.session.add_lint(lint::builtin::PRIVATE_IN_PUBLIC,
817 import_directive.span,
821 if name_binding.defined_with(modifier) {
822 let namespace_name = match ns {
826 debug!("(resolving glob import) ... for {} target", namespace_name);
827 if dest_import_resolution.shadowable() == Shadowable::Never {
828 let msg = format!("a {} named `{}` has already been imported in this module",
831 span_err!(self.resolver.session, import_directive.span, E0251, "{}", msg);
833 let target = Target::new(containing_module,
834 name_binding.clone(),
835 import_directive.shadowable);
836 dest_import_resolution.target = Some(target);
837 dest_import_resolution.id = id;
838 dest_import_resolution.is_public = is_public;
839 self.add_export(module_, name, &dest_import_resolution);
843 self.check_for_conflicts_between_imports_and_items(module_,
844 dest_import_resolution,
845 import_directive.span,
849 fn add_export(&mut self, module: Module<'b>, name: Name, resolution: &ImportResolution<'b>) {
850 if !resolution.is_public { return }
851 let node_id = match module.def_id() {
852 Some(def_id) => self.resolver.ast_map.as_local_node_id(def_id).unwrap(),
855 let export = match resolution.target.as_ref().unwrap().binding.def() {
856 Some(def) => Export { name: name, def_id: def.def_id() },
859 self.resolver.export_map.entry(node_id).or_insert(Vec::new()).push(export);
862 /// Checks that imported names and items don't have the same name.
863 fn check_for_conflicting_import(&mut self,
864 import_resolution: &ImportResolution,
867 namespace: Namespace) {
868 let target = &import_resolution.target;
869 debug!("check_for_conflicting_import: {}; target exists: {}",
874 Some(ref target) if target.shadowable != Shadowable::Always => {
875 let ns_word = match namespace {
877 match target.binding.module() {
878 Some(ref module) if module.is_normal() => "module",
879 Some(ref module) if module.is_trait() => "trait",
885 let use_id = import_resolution.id;
886 let item = self.resolver.ast_map.expect_item(use_id);
887 let mut err = struct_span_err!(self.resolver.session,
890 "a {} named `{}` has already been imported \
896 "previous import of `{}` here",
904 /// Checks that an import is actually importable
905 fn check_that_import_is_importable(&mut self,
906 name_binding: &NameBinding,
909 if !name_binding.defined_with(DefModifiers::IMPORTABLE) {
910 let msg = format!("`{}` is not directly importable", name);
911 span_err!(self.resolver.session, import_span, E0253, "{}", &msg[..]);
915 /// Checks that imported names and items don't have the same name.
916 fn check_for_conflicts_between_imports_and_items(&mut self,
918 import: &ImportResolution<'b>,
920 (name, ns): (Name, Namespace)) {
921 // Check for item conflicts.
922 let name_binding = match module.get_child(name, ns) {
924 // There can't be any conflicts.
927 Some(name_binding) => name_binding,
931 match import.target {
932 Some(ref target) if target.shadowable != Shadowable::Always => {
933 let mut err = struct_span_err!(self.resolver.session,
936 "import `{}` conflicts with \
937 value in this module",
939 if let Some(span) = name_binding.span {
940 err.span_note(span, "conflicting value here");
947 match import.target {
948 Some(ref target) if target.shadowable != Shadowable::Always => {
949 if name_binding.is_extern_crate() {
950 let msg = format!("import `{0}` conflicts with imported crate \
951 in this module (maybe you meant `use {0}::*`?)",
953 span_err!(self.resolver.session, import_span, E0254, "{}", &msg[..]);
957 let (what, note) = match name_binding.module() {
958 Some(ref module) if module.is_normal() =>
959 ("existing submodule", "note conflicting module here"),
960 Some(ref module) if module.is_trait() =>
961 ("trait in this module", "note conflicting trait here"),
962 _ => ("type in this module", "note conflicting type here"),
964 let mut err = struct_span_err!(self.resolver.session,
967 "import `{}` conflicts with {}",
970 if let Some(span) = name_binding.span {
971 err.span_note(span, note);
981 fn import_path_to_string(names: &[Name], subclass: ImportDirectiveSubclass) -> String {
982 if names.is_empty() {
983 import_directive_subclass_to_string(subclass)
986 names_to_string(names),
987 import_directive_subclass_to_string(subclass)))
992 fn import_directive_subclass_to_string(subclass: ImportDirectiveSubclass) -> String {
994 SingleImport(_, source) => source.to_string(),
995 GlobImport => "*".to_string(),
999 pub fn resolve_imports(resolver: &mut Resolver) {
1000 let mut import_resolver = ImportResolver { resolver: resolver };
1001 import_resolver.resolve_imports();