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::*;
13 use {AmbiguityError, CrateLint, Module, ModuleOrUniformRoot, PerNS};
14 use Namespace::{self, TypeNS, MacroNS};
15 use {NameBinding, NameBindingKind, ToNameBinding, PathResult, PrivacyError};
17 use {names_to_string, module_to_string};
18 use {resolve_error, ResolutionError};
20 use rustc_data_structures::ptr_key::PtrKey;
22 use rustc::lint::builtin::BuiltinLintDiagnostics;
23 use rustc::lint::builtin::{DUPLICATE_MACRO_EXPORTS, PUB_USE_OF_PRIVATE_EXTERN_CRATE};
24 use rustc::hir::def_id::{CRATE_DEF_INDEX, DefId};
25 use rustc::hir::def::*;
26 use rustc::session::DiagnosticMessageId;
27 use rustc::util::nodemap::{FxHashMap, FxHashSet};
29 use syntax::ast::{Ident, Name, NodeId, CRATE_NODE_ID};
30 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
31 use syntax::ext::hygiene::Mark;
32 use syntax::symbol::keywords;
33 use syntax::util::lev_distance::find_best_match_for_name;
36 use std::cell::{Cell, RefCell};
39 /// Contains data for specific types of import directives.
40 #[derive(Clone, Debug)]
41 pub enum ImportDirectiveSubclass<'a> {
45 result: PerNS<Cell<Result<&'a NameBinding<'a>, Determinacy>>>,
50 max_vis: Cell<ty::Visibility>, // The visibility of the greatest re-export.
51 // n.b. `max_vis` is only used in `finalize_import` to check for re-export errors.
53 ExternCrate(Option<Name>),
57 /// One import directive.
58 #[derive(Debug,Clone)]
59 pub struct ImportDirective<'a> {
60 /// The id of the `extern crate`, `UseTree` etc that imported this `ImportDirective`.
62 /// In the case where the `ImportDirective` was expanded from a "nested" use tree,
63 /// this id is the id of the leaf tree. For example:
65 /// ```ignore (pacify the mercilous tidy)
66 /// use foo::bar::{a, b}
69 /// If this is the import directive for `foo::bar::a`, we would have the id of the `UseTree`
70 /// for `a` in this field.
73 /// The `id` of the "root" use-kind -- this is always the same as
74 /// `id` except in the case of "nested" use trees, in which case
75 /// it will be the `id` of the root use tree. e.g., in the example
76 /// from `id`, this would be the id of the `use foo::bar`
80 /// Span of this use tree.
83 /// Span of the *root* use tree (see `root_id`).
86 pub parent: Module<'a>,
87 pub module_path: Vec<Ident>,
88 /// The resolution of `module_path`.
89 pub imported_module: Cell<Option<ModuleOrUniformRoot<'a>>>,
90 pub subclass: ImportDirectiveSubclass<'a>,
91 pub vis: Cell<ty::Visibility>,
96 impl<'a> ImportDirective<'a> {
97 pub fn is_glob(&self) -> bool {
98 match self.subclass { ImportDirectiveSubclass::GlobImport { .. } => true, _ => false }
101 crate fn crate_lint(&self) -> CrateLint {
102 CrateLint::UsePath { root_id: self.root_id, root_span: self.root_span }
106 #[derive(Clone, Default, Debug)]
107 /// Records information about the resolution of a name in a namespace of a module.
108 pub struct NameResolution<'a> {
109 /// Single imports that may define the name in the namespace.
110 /// Import directives are arena-allocated, so it's ok to use pointers as keys.
111 single_imports: FxHashSet<PtrKey<'a, ImportDirective<'a>>>,
112 /// The least shadowable known binding for this name, or None if there are no known bindings.
113 pub binding: Option<&'a NameBinding<'a>>,
114 shadowed_glob: Option<&'a NameBinding<'a>>,
117 impl<'a> NameResolution<'a> {
118 // Returns the binding for the name if it is known or None if it not known.
119 fn binding(&self) -> Option<&'a NameBinding<'a>> {
120 self.binding.and_then(|binding| {
121 if !binding.is_glob_import() ||
122 self.single_imports.is_empty() { Some(binding) } else { None }
127 impl<'a, 'crateloader> Resolver<'a, 'crateloader> {
128 fn resolution(&self, module: Module<'a>, ident: Ident, ns: Namespace)
129 -> &'a RefCell<NameResolution<'a>> {
130 *module.resolutions.borrow_mut().entry((ident.modern(), ns))
131 .or_insert_with(|| self.arenas.alloc_name_resolution())
134 /// Attempts to resolve `ident` in namespaces `ns` of `module`.
135 /// Invariant: if `record_used` is `Some`, expansion and import resolution must be complete.
136 pub fn resolve_ident_in_module_unadjusted(&mut self,
137 module: ModuleOrUniformRoot<'a>,
140 restricted_shadowing: bool,
143 -> Result<&'a NameBinding<'a>, Determinacy> {
144 let module = match module {
145 ModuleOrUniformRoot::Module(module) => module,
146 ModuleOrUniformRoot::UniformRoot(root) => {
148 root != keywords::Extern.name() &&
150 ident.name == keywords::Crate.name() ||
151 ident.name == keywords::DollarCrate.name()
154 self.resolve_crate_root(ident)
155 } else if !ident.is_path_segment_keyword() {
157 self.crate_loader.process_path_extern(ident.name, ident.span);
158 self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX })
160 return Err(Determined);
162 self.populate_module_if_necessary(crate_root);
163 let binding = (crate_root, ty::Visibility::Public,
164 ident.span, Mark::root()).to_name_binding(self.arenas);
169 self.populate_module_if_necessary(module);
171 let resolution = self.resolution(module, ident, ns)
173 .map_err(|_| Determined)?; // This happens when there is a cycle of imports
175 if let Some(binding) = resolution.binding {
176 if !restricted_shadowing && binding.expansion != Mark::root() {
177 if let NameBindingKind::Def(_, true) = binding.kind {
178 self.macro_expanded_macro_export_errors.insert((path_span, binding.span));
184 if let Some(binding) = resolution.binding {
185 if let Some(shadowed_glob) = resolution.shadowed_glob {
186 let name = ident.name;
187 // Forbid expanded shadowing to avoid time travel.
188 if restricted_shadowing &&
189 binding.expansion != Mark::root() &&
190 ns != MacroNS && // In MacroNS, `try_define` always forbids this shadowing
191 binding.def() != shadowed_glob.def() {
192 self.ambiguity_errors.push(AmbiguityError {
201 if self.record_use(ident, ns, binding, path_span) {
202 return Ok(self.dummy_binding);
204 if !self.is_accessible(binding.vis) {
205 self.privacy_errors.push(PrivacyError(path_span, ident.name, binding));
209 return resolution.binding.ok_or(Determined);
212 let check_usable = |this: &mut Self, binding: &'a NameBinding<'a>| {
213 // `extern crate` are always usable for backwards compatibility, see issue #37020.
214 let usable = this.is_accessible(binding.vis) || binding.is_extern_crate();
215 if usable { Ok(binding) } else { Err(Determined) }
218 // Items and single imports are not shadowable, if we have one, then it's determined.
219 if let Some(binding) = resolution.binding {
220 if !binding.is_glob_import() {
221 return check_usable(self, binding);
225 // --- From now on we either have a glob resolution or no resolution. ---
227 // Check if one of single imports can still define the name,
228 // if it can then our result is not determined and can be invalidated.
229 for single_import in &resolution.single_imports {
230 if !self.is_accessible(single_import.vis.get()) {
233 let module = unwrap_or!(single_import.imported_module.get(), return Err(Undetermined));
234 let ident = match single_import.subclass {
235 SingleImport { source, .. } => source,
238 match self.resolve_ident_in_module(module, ident, ns, false, path_span) {
239 Err(Determined) => continue,
240 Ok(_) | Err(Undetermined) => return Err(Undetermined),
244 // So we have a resolution that's from a glob import. This resolution is determined
245 // if it cannot be shadowed by some new item/import expanded from a macro.
246 // This happens either if there are no unexpanded macros, or expanded names cannot
247 // shadow globs (that happens in macro namespace or with restricted shadowing).
249 // Additionally, any macro in any module can plant names in the root module if it creates
250 // `macro_export` macros, so the root module effectively has unresolved invocations if any
251 // module has unresolved invocations.
252 // However, it causes resolution/expansion to stuck too often (#53144), so, to make
253 // progress, we have to ignore those potential unresolved invocations from other modules
254 // and prohibit access to macro-expanded `macro_export` macros instead (unless restricted
255 // shadowing is enabled, see `macro_expanded_macro_export_errors`).
256 let unexpanded_macros = !module.unresolved_invocations.borrow().is_empty();
257 if let Some(binding) = resolution.binding {
258 if !unexpanded_macros || ns == MacroNS || restricted_shadowing {
259 return check_usable(self, binding);
261 return Err(Undetermined);
265 // --- From now on we have no resolution. ---
267 // Now we are in situation when new item/import can appear only from a glob or a macro
268 // expansion. With restricted shadowing names from globs and macro expansions cannot
269 // shadow names from outer scopes, so we can freely fallback from module search to search
270 // in outer scopes. To continue search in outer scopes we have to lie a bit and return
271 // `Determined` to `resolve_lexical_macro_path_segment` even if the correct answer
272 // for in-module resolution could be `Undetermined`.
273 if restricted_shadowing {
274 return Err(Determined);
277 // Check if one of unexpanded macros can still define the name,
278 // if it can then our "no resolution" result is not determined and can be invalidated.
279 if unexpanded_macros {
280 return Err(Undetermined);
283 // Check if one of glob imports can still define the name,
284 // if it can then our "no resolution" result is not determined and can be invalidated.
285 for glob_import in module.globs.borrow().iter() {
286 if !self.is_accessible(glob_import.vis.get()) {
289 let module = match glob_import.imported_module.get() {
290 Some(ModuleOrUniformRoot::Module(module)) => module,
291 Some(ModuleOrUniformRoot::UniformRoot(_)) => continue,
292 None => return Err(Undetermined),
294 let (orig_current_module, mut ident) = (self.current_module, ident.modern());
295 match ident.span.glob_adjust(module.expansion, glob_import.span.ctxt().modern()) {
296 Some(Some(def)) => self.current_module = self.macro_def_scope(def),
300 let result = self.resolve_ident_in_module_unadjusted(
301 ModuleOrUniformRoot::Module(module),
308 self.current_module = orig_current_module;
310 Err(Determined) => continue,
311 Ok(_) | Err(Undetermined) => return Err(Undetermined),
315 // No resolution and no one else can define the name - determinate error.
319 // Add an import directive to the current module.
320 pub fn add_import_directive(&mut self,
321 module_path: Vec<Ident>,
322 subclass: ImportDirectiveSubclass<'a>,
329 let current_module = self.current_module;
330 let directive = self.arenas.alloc_import_directive(ImportDirective {
331 parent: current_module,
333 imported_module: Cell::new(None),
341 used: Cell::new(false),
344 self.indeterminate_imports.push(directive);
345 match directive.subclass {
346 SingleImport { target, type_ns_only, .. } => {
347 self.per_ns(|this, ns| if !type_ns_only || ns == TypeNS {
348 let mut resolution = this.resolution(current_module, target, ns).borrow_mut();
349 resolution.single_imports.insert(PtrKey(directive));
352 // We don't add prelude imports to the globs since they only affect lexical scopes,
353 // which are not relevant to import resolution.
354 GlobImport { is_prelude: true, .. } => {}
355 GlobImport { .. } => self.current_module.globs.borrow_mut().push(directive),
360 // Given a binding and an import directive that resolves to it,
361 // return the corresponding binding defined by the import directive.
362 pub fn import(&self, binding: &'a NameBinding<'a>, directive: &'a ImportDirective<'a>)
363 -> &'a NameBinding<'a> {
364 let vis = if binding.pseudo_vis().is_at_least(directive.vis.get(), self) ||
365 // c.f. `PUB_USE_OF_PRIVATE_EXTERN_CRATE`
366 !directive.is_glob() && binding.is_extern_crate() {
372 if let GlobImport { ref max_vis, .. } = directive.subclass {
373 if vis == directive.vis.get() || vis.is_at_least(max_vis.get(), self) {
378 self.arenas.alloc_name_binding(NameBinding {
379 kind: NameBindingKind::Import {
382 used: Cell::new(false),
384 span: directive.span,
386 expansion: directive.expansion,
390 // Define the name or return the existing binding if there is a collision.
391 pub fn try_define(&mut self,
395 binding: &'a NameBinding<'a>)
396 -> Result<(), &'a NameBinding<'a>> {
397 self.update_resolution(module, ident, ns, |this, resolution| {
398 if let Some(old_binding) = resolution.binding {
399 if binding.is_glob_import() {
400 if !old_binding.is_glob_import() &&
401 !(ns == MacroNS && old_binding.expansion != Mark::root()) {
402 resolution.shadowed_glob = Some(binding);
403 } else if binding.def() != old_binding.def() {
404 resolution.binding = Some(this.ambiguity(old_binding, binding));
405 } else if !old_binding.vis.is_at_least(binding.vis, &*this) {
406 // We are glob-importing the same item but with greater visibility.
407 resolution.binding = Some(binding);
409 } else if old_binding.is_glob_import() {
410 if ns == MacroNS && binding.expansion != Mark::root() &&
411 binding.def() != old_binding.def() {
412 resolution.binding = Some(this.ambiguity(binding, old_binding));
414 resolution.binding = Some(binding);
415 resolution.shadowed_glob = Some(old_binding);
417 } else if let (&NameBindingKind::Def(_, true), &NameBindingKind::Def(_, true)) =
418 (&old_binding.kind, &binding.kind) {
420 this.session.buffer_lint_with_diagnostic(
421 DUPLICATE_MACRO_EXPORTS,
424 &format!("a macro named `{}` has already been exported", ident),
425 BuiltinLintDiagnostics::DuplicatedMacroExports(
426 ident, old_binding.span, binding.span));
428 resolution.binding = Some(binding);
430 return Err(old_binding);
433 resolution.binding = Some(binding);
440 pub fn ambiguity(&self, b1: &'a NameBinding<'a>, b2: &'a NameBinding<'a>)
441 -> &'a NameBinding<'a> {
442 self.arenas.alloc_name_binding(NameBinding {
443 kind: NameBindingKind::Ambiguity { b1, b2 },
444 vis: if b1.vis.is_at_least(b2.vis, self) { b1.vis } else { b2.vis },
446 expansion: Mark::root(),
450 // Use `f` to mutate the resolution of the name in the module.
451 // If the resolution becomes a success, define it in the module's glob importers.
452 fn update_resolution<T, F>(&mut self, module: Module<'a>, ident: Ident, ns: Namespace, f: F)
454 where F: FnOnce(&mut Resolver<'a, 'crateloader>, &mut NameResolution<'a>) -> T
456 // Ensure that `resolution` isn't borrowed when defining in the module's glob importers,
457 // during which the resolution might end up getting re-defined via a glob cycle.
459 let resolution = &mut *self.resolution(module, ident, ns).borrow_mut();
460 let old_binding = resolution.binding();
462 let t = f(self, resolution);
464 match resolution.binding() {
465 _ if old_binding.is_some() => return t,
467 Some(binding) => match old_binding {
468 Some(old_binding) if ptr::eq(old_binding, binding) => return t,
474 // Define `binding` in `module`s glob importers.
475 for directive in module.glob_importers.borrow_mut().iter() {
476 let mut ident = ident.modern();
477 let scope = match ident.span.reverse_glob_adjust(module.expansion,
478 directive.span.ctxt().modern()) {
479 Some(Some(def)) => self.macro_def_scope(def),
480 Some(None) => directive.parent,
483 if self.is_accessible_from(binding.vis, scope) {
484 let imported_binding = self.import(binding, directive);
485 let _ = self.try_define(directive.parent, ident, ns, imported_binding);
492 // Define a "dummy" resolution containing a Def::Err as a placeholder for a
494 fn import_dummy_binding(&mut self, directive: &'a ImportDirective<'a>) {
495 if let SingleImport { target, .. } = directive.subclass {
496 let dummy_binding = self.dummy_binding;
497 let dummy_binding = self.import(dummy_binding, directive);
498 self.per_ns(|this, ns| {
499 let _ = this.try_define(directive.parent, target, ns, dummy_binding);
505 pub struct ImportResolver<'a, 'b: 'a, 'c: 'a + 'b> {
506 pub resolver: &'a mut Resolver<'b, 'c>,
509 impl<'a, 'b: 'a, 'c: 'a + 'b> ::std::ops::Deref for ImportResolver<'a, 'b, 'c> {
510 type Target = Resolver<'b, 'c>;
511 fn deref(&self) -> &Resolver<'b, 'c> {
516 impl<'a, 'b: 'a, 'c: 'a + 'b> ::std::ops::DerefMut for ImportResolver<'a, 'b, 'c> {
517 fn deref_mut(&mut self) -> &mut Resolver<'b, 'c> {
522 impl<'a, 'b: 'a, 'c: 'a + 'b> ty::DefIdTree for &'a ImportResolver<'a, 'b, 'c> {
523 fn parent(self, id: DefId) -> Option<DefId> {
524 self.resolver.parent(id)
528 impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
531 // This is a fixed-point algorithm. We resolve imports until our efforts
532 // are stymied by an unresolved import; then we bail out of the current
533 // module and continue. We terminate successfully once no more imports
534 // remain or unsuccessfully when no forward progress in resolving imports
537 /// Resolves all imports for the crate. This method performs the fixed-
539 pub fn resolve_imports(&mut self) {
540 let mut prev_num_indeterminates = self.indeterminate_imports.len() + 1;
541 while self.indeterminate_imports.len() < prev_num_indeterminates {
542 prev_num_indeterminates = self.indeterminate_imports.len();
543 for import in mem::replace(&mut self.indeterminate_imports, Vec::new()) {
544 match self.resolve_import(&import) {
545 true => self.determined_imports.push(import),
546 false => self.indeterminate_imports.push(import),
552 pub fn finalize_imports(&mut self) {
553 for module in self.arenas.local_modules().iter() {
554 self.finalize_resolutions_in(module);
557 let mut errors = false;
558 let mut seen_spans = FxHashSet();
559 for i in 0 .. self.determined_imports.len() {
560 let import = self.determined_imports[i];
561 if let Some((span, err)) = self.finalize_import(import) {
564 if let SingleImport { source, ref result, .. } = import.subclass {
565 if source.name == "self" {
566 // Silence `unresolved import` error if E0429 is already emitted
567 match result.value_ns.get() {
568 Err(Determined) => continue,
574 // If the error is a single failed import then create a "fake" import
575 // resolution for it so that later resolve stages won't complain.
576 self.import_dummy_binding(import);
577 if !seen_spans.contains(&span) {
578 let path = import_path_to_string(&import.module_path[..],
581 let error = ResolutionError::UnresolvedImport(Some((span, &path, &err)));
582 resolve_error(self.resolver, span, error);
583 seen_spans.insert(span);
588 // Report unresolved imports only if no hard error was already reported
589 // to avoid generating multiple errors on the same import.
591 if let Some(import) = self.indeterminate_imports.iter().next() {
592 let error = ResolutionError::UnresolvedImport(None);
593 resolve_error(self.resolver, import.span, error);
598 /// Attempts to resolve the given import, returning true if its resolution is determined.
599 /// If successful, the resolved bindings are written into the module.
600 fn resolve_import(&mut self, directive: &'b ImportDirective<'b>) -> bool {
601 debug!("(resolving import for module) resolving import `{}::...` in `{}`",
602 names_to_string(&directive.module_path[..]),
603 module_to_string(self.current_module).unwrap_or("???".to_string()));
605 self.current_module = directive.parent;
607 let module = if let Some(module) = directive.imported_module.get() {
610 let vis = directive.vis.get();
611 // For better failure detection, pretend that the import will not define any names
612 // while resolving its module path.
613 directive.vis.set(ty::Visibility::Invisible);
614 let result = self.resolve_path(
615 Some(ModuleOrUniformRoot::UniformRoot(keywords::Invalid.name())),
616 &directive.module_path[..],
620 directive.crate_lint(),
622 directive.vis.set(vis);
625 PathResult::Module(module) => module,
626 PathResult::Indeterminate => return false,
631 directive.imported_module.set(Some(module));
632 let (source, target, result, type_ns_only) = match directive.subclass {
633 SingleImport { source, target, ref result, type_ns_only } =>
634 (source, target, result, type_ns_only),
635 GlobImport { .. } => {
636 self.resolve_glob_import(directive);
642 let mut indeterminate = false;
643 self.per_ns(|this, ns| if !type_ns_only || ns == TypeNS {
644 if let Err(Undetermined) = result[ns].get() {
645 result[ns].set(this.resolve_ident_in_module(module,
654 let parent = directive.parent;
655 match result[ns].get() {
656 Err(Undetermined) => indeterminate = true,
658 this.update_resolution(parent, target, ns, |_, resolution| {
659 resolution.single_imports.remove(&PtrKey(directive));
662 Ok(binding) if !binding.is_importable() => {
663 let msg = format!("`{}` is not directly importable", target);
664 struct_span_err!(this.session, directive.span, E0253, "{}", &msg)
665 .span_label(directive.span, "cannot be imported directly")
667 // Do not import this illegal binding. Import a dummy binding and pretend
668 // everything is fine
669 this.import_dummy_binding(directive);
672 let imported_binding = this.import(binding, directive);
673 let conflict = this.try_define(parent, target, ns, imported_binding);
674 if let Err(old_binding) = conflict {
675 this.report_conflict(parent, target, ns, imported_binding, old_binding);
684 // If appropriate, returns an error to report.
685 fn finalize_import(&mut self, directive: &'b ImportDirective<'b>) -> Option<(Span, String)> {
686 self.current_module = directive.parent;
687 let ImportDirective { ref module_path, span, .. } = *directive;
689 let module_result = self.resolve_path(
690 Some(ModuleOrUniformRoot::UniformRoot(keywords::Invalid.name())),
695 directive.crate_lint(),
697 let module = match module_result {
698 PathResult::Module(module) => module,
699 PathResult::Failed(span, msg, false) => {
700 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
703 PathResult::Failed(span, msg, true) => {
704 let (mut self_path, mut self_result) = (module_path.clone(), None);
705 let is_special = |ident: Ident| ident.is_path_segment_keyword() &&
706 ident.name != keywords::CrateRoot.name();
707 if !self_path.is_empty() && !is_special(self_path[0]) &&
708 !(self_path.len() > 1 && is_special(self_path[1])) {
709 self_path[0].name = keywords::SelfValue.name();
710 self_result = Some(self.resolve_path(None, &self_path, None, false,
711 span, CrateLint::No));
713 return if let Some(PathResult::Module(..)) = self_result {
714 Some((span, format!("Did you mean `{}`?", names_to_string(&self_path[..]))))
722 let (ident, result, type_ns_only) = match directive.subclass {
723 SingleImport { source, ref result, type_ns_only, .. } => (source, result, type_ns_only),
724 GlobImport { is_prelude, ref max_vis } => {
725 if module_path.len() <= 1 {
726 // HACK(eddyb) `lint_if_path_starts_with_module` needs at least
727 // 2 segments, so the `resolve_path` above won't trigger it.
728 let mut full_path = module_path.clone();
729 full_path.push(keywords::Invalid.ident());
730 self.lint_if_path_starts_with_module(
731 directive.crate_lint(),
738 if let ModuleOrUniformRoot::Module(module) = module {
739 if module.def_id() == directive.parent.def_id() {
740 // Importing a module into itself is not allowed.
741 return Some((directive.span,
742 "Cannot glob-import a module into itself.".to_string()));
746 max_vis.get() != ty::Visibility::Invisible && // Allow empty globs.
747 !max_vis.get().is_at_least(directive.vis.get(), &*self) {
748 let msg = "A non-empty glob must import something with the glob's visibility";
749 self.session.span_err(directive.span, msg);
756 let mut all_ns_err = true;
757 self.per_ns(|this, ns| if !type_ns_only || ns == TypeNS {
758 if let Ok(binding) = result[ns].get() {
760 if this.record_use(ident, ns, binding, directive.span) {
761 if let ModuleOrUniformRoot::Module(module) = module {
762 this.resolution(module, ident, ns).borrow_mut().binding =
763 Some(this.dummy_binding);
770 let mut all_ns_failed = true;
771 self.per_ns(|this, ns| if !type_ns_only || ns == TypeNS {
772 match this.resolve_ident_in_module(module, ident, ns, true, span) {
773 Ok(_) => all_ns_failed = false,
778 return if all_ns_failed {
779 let resolutions = match module {
780 ModuleOrUniformRoot::Module(module) =>
781 Some(module.resolutions.borrow()),
782 ModuleOrUniformRoot::UniformRoot(_) => None,
784 let resolutions = resolutions.as_ref().into_iter().flat_map(|r| r.iter());
785 let names = resolutions.filter_map(|(&(ref i, _), resolution)| {
786 if *i == ident { return None; } // Never suggest the same name
787 match *resolution.borrow() {
788 NameResolution { binding: Some(name_binding), .. } => {
789 match name_binding.kind {
790 NameBindingKind::Import { binding, .. } => {
792 // Never suggest the name that has binding error
793 // i.e. the name that cannot be previously resolved
794 NameBindingKind::Def(Def::Err, _) => return None,
801 NameResolution { ref single_imports, .. }
802 if single_imports.is_empty() => None,
807 match find_best_match_for_name(names, &ident.as_str(), None) {
808 Some(name) => format!(". Did you mean to use `{}`?", name),
809 None => "".to_owned(),
811 let msg = match module {
812 ModuleOrUniformRoot::Module(module) => {
813 let module_str = module_to_string(module);
814 if let Some(module_str) = module_str {
815 format!("no `{}` in `{}`{}", ident, module_str, lev_suggestion)
817 format!("no `{}` in the root{}", ident, lev_suggestion)
820 ModuleOrUniformRoot::UniformRoot(_) => {
821 if !ident.is_path_segment_keyword() {
822 format!("no `{}` external crate{}", ident, lev_suggestion)
824 // HACK(eddyb) this shows up for `self` & `super`, which
825 // should work instead - for now keep the same error message.
826 format!("no `{}` in the root{}", ident, lev_suggestion)
832 // `resolve_ident_in_module` reported a privacy error.
833 self.import_dummy_binding(directive);
838 let mut reexport_error = None;
839 let mut any_successful_reexport = false;
840 self.per_ns(|this, ns| {
841 if let Ok(binding) = result[ns].get() {
842 let vis = directive.vis.get();
843 if !binding.pseudo_vis().is_at_least(vis, &*this) {
844 reexport_error = Some((ns, binding));
846 any_successful_reexport = true;
851 // All namespaces must be re-exported with extra visibility for an error to occur.
852 if !any_successful_reexport {
853 let (ns, binding) = reexport_error.unwrap();
854 if ns == TypeNS && binding.is_extern_crate() {
855 let msg = format!("extern crate `{}` is private, and cannot be \
856 re-exported (error E0365), consider declaring with \
859 self.session.buffer_lint(PUB_USE_OF_PRIVATE_EXTERN_CRATE,
863 } else if ns == TypeNS {
864 struct_span_err!(self.session, directive.span, E0365,
865 "`{}` is private, and cannot be re-exported", ident)
866 .span_label(directive.span, format!("re-export of private `{}`", ident))
867 .note(&format!("consider declaring type or module `{}` with `pub`", ident))
870 let msg = format!("`{}` is private, and cannot be re-exported", ident);
872 format!("consider marking `{}` as `pub` in the imported module", ident);
873 struct_span_err!(self.session, directive.span, E0364, "{}", &msg)
874 .span_note(directive.span, ¬e_msg)
879 if module_path.len() <= 1 {
880 // HACK(eddyb) `lint_if_path_starts_with_module` needs at least
881 // 2 segments, so the `resolve_path` above won't trigger it.
882 let mut full_path = module_path.clone();
883 full_path.push(ident);
884 self.per_ns(|this, ns| {
885 if let Ok(binding) = result[ns].get() {
886 this.lint_if_path_starts_with_module(
887 directive.crate_lint(),
896 // Record what this import resolves to for later uses in documentation,
897 // this may resolve to either a value or a type, but for documentation
898 // purposes it's good enough to just favor one over the other.
899 self.per_ns(|this, ns| if let Some(binding) = result[ns].get().ok() {
900 let import = this.import_map.entry(directive.id).or_default();
901 import[ns] = Some(PathResolution::new(binding.def()));
904 debug!("(resolving single import) successfully resolved import");
908 fn resolve_glob_import(&mut self, directive: &'b ImportDirective<'b>) {
909 let module = match directive.imported_module.get().unwrap() {
910 ModuleOrUniformRoot::Module(module) => module,
911 ModuleOrUniformRoot::UniformRoot(_) => {
912 self.session.span_err(directive.span,
913 "cannot glob-import all possible crates");
918 self.populate_module_if_necessary(module);
920 if let Some(Def::Trait(_)) = module.def() {
921 self.session.span_err(directive.span, "items in traits are not importable.");
923 } else if module.def_id() == directive.parent.def_id() {
925 } else if let GlobImport { is_prelude: true, .. } = directive.subclass {
926 self.prelude = Some(module);
930 // Add to module's glob_importers
931 module.glob_importers.borrow_mut().push(directive);
933 // Ensure that `resolutions` isn't borrowed during `try_define`,
934 // since it might get updated via a glob cycle.
935 let bindings = module.resolutions.borrow().iter().filter_map(|(&ident, resolution)| {
936 resolution.borrow().binding().map(|binding| (ident, binding))
937 }).collect::<Vec<_>>();
938 for ((mut ident, ns), binding) in bindings {
939 let scope = match ident.span.reverse_glob_adjust(module.expansion,
940 directive.span.ctxt().modern()) {
941 Some(Some(def)) => self.macro_def_scope(def),
942 Some(None) => self.current_module,
945 if self.is_accessible_from(binding.pseudo_vis(), scope) {
946 let imported_binding = self.import(binding, directive);
947 let _ = self.try_define(directive.parent, ident, ns, imported_binding);
951 // Record the destination of this import
952 self.record_def(directive.id, PathResolution::new(module.def().unwrap()));
955 // Miscellaneous post-processing, including recording re-exports,
956 // reporting conflicts, and reporting unresolved imports.
957 fn finalize_resolutions_in(&mut self, module: Module<'b>) {
958 // Since import resolution is finished, globs will not define any more names.
959 *module.globs.borrow_mut() = Vec::new();
961 let mut reexports = Vec::new();
962 let mut exported_macro_names = FxHashMap();
963 if ptr::eq(module, self.graph_root) {
964 let macro_exports = mem::replace(&mut self.macro_exports, Vec::new());
965 for export in macro_exports.into_iter().rev() {
966 if let Some(later_span) = exported_macro_names.insert(export.ident.modern(),
968 self.session.buffer_lint_with_diagnostic(
969 DUPLICATE_MACRO_EXPORTS,
972 &format!("a macro named `{}` has already been exported", export.ident),
973 BuiltinLintDiagnostics::DuplicatedMacroExports(
974 export.ident, export.span, later_span));
976 reexports.push(export);
981 for (&(ident, ns), resolution) in module.resolutions.borrow().iter() {
982 let resolution = &mut *resolution.borrow_mut();
983 let binding = match resolution.binding {
984 Some(binding) => binding,
988 if binding.is_import() || binding.is_macro_def() {
989 let def = binding.def();
991 if !def.def_id().is_local() {
992 self.cstore.export_macros_untracked(def.def_id().krate);
994 if let Def::Macro(..) = def {
995 if let Some(&span) = exported_macro_names.get(&ident.modern()) {
997 format!("a macro named `{}` has already been exported", ident);
998 self.session.struct_span_err(span, &msg)
999 .span_label(span, format!("`{}` already exported", ident))
1000 .span_note(binding.span, "previous macro export here")
1004 reexports.push(Export {
1005 ident: ident.modern(),
1013 match binding.kind {
1014 NameBindingKind::Import { binding: orig_binding, directive, .. } => {
1015 if ns == TypeNS && orig_binding.is_variant() &&
1016 !orig_binding.vis.is_at_least(binding.vis, &*self) {
1017 let msg = match directive.subclass {
1018 ImportDirectiveSubclass::SingleImport { .. } => {
1019 format!("variant `{}` is private and cannot be re-exported",
1022 ImportDirectiveSubclass::GlobImport { .. } => {
1023 let msg = "enum is private and its variants \
1024 cannot be re-exported".to_owned();
1025 let error_id = (DiagnosticMessageId::ErrorId(0), // no code?!
1028 let fresh = self.session.one_time_diagnostics
1029 .borrow_mut().insert(error_id);
1035 ref s @ _ => bug!("unexpected import subclass {:?}", s)
1037 let mut err = self.session.struct_span_err(binding.span, &msg);
1039 let imported_module = match directive.imported_module.get() {
1040 Some(ModuleOrUniformRoot::Module(module)) => module,
1041 _ => bug!("module should exist"),
1043 let resolutions = imported_module.parent.expect("parent should exist")
1044 .resolutions.borrow();
1045 let enum_path_segment_index = directive.module_path.len() - 1;
1046 let enum_ident = directive.module_path[enum_path_segment_index];
1048 let enum_resolution = resolutions.get(&(enum_ident, TypeNS))
1049 .expect("resolution should exist");
1050 let enum_span = enum_resolution.borrow()
1051 .binding.expect("binding should exist")
1053 let enum_def_span = self.session.codemap().def_span(enum_span);
1054 let enum_def_snippet = self.session.codemap()
1055 .span_to_snippet(enum_def_span).expect("snippet should exist");
1056 // potentially need to strip extant `crate`/`pub(path)` for suggestion
1057 let after_vis_index = enum_def_snippet.find("enum")
1058 .expect("`enum` keyword should exist in snippet");
1059 let suggestion = format!("pub {}",
1060 &enum_def_snippet[after_vis_index..]);
1063 .diag_span_suggestion_once(&mut err,
1064 DiagnosticMessageId::ErrorId(0),
1066 "consider making the enum public",
1075 if reexports.len() > 0 {
1076 if let Some(def_id) = module.def_id() {
1077 self.export_map.insert(def_id, reexports);
1083 fn import_path_to_string(names: &[Ident],
1084 subclass: &ImportDirectiveSubclass,
1085 span: Span) -> String {
1086 let pos = names.iter()
1087 .position(|p| span == p.span && p.name != keywords::CrateRoot.name());
1088 let global = !names.is_empty() && names[0].name == keywords::CrateRoot.name();
1089 if let Some(pos) = pos {
1090 let names = if global { &names[1..pos + 1] } else { &names[..pos + 1] };
1091 names_to_string(names)
1093 let names = if global { &names[1..] } else { names };
1094 if names.is_empty() {
1095 import_directive_subclass_to_string(subclass)
1098 names_to_string(names),
1099 import_directive_subclass_to_string(subclass))
1104 fn import_directive_subclass_to_string(subclass: &ImportDirectiveSubclass) -> String {
1106 SingleImport { source, .. } => source.to_string(),
1107 GlobImport { .. } => "*".to_string(),
1108 ExternCrate(_) => "<extern crate>".to_string(),
1109 MacroUse => "#[macro_use]".to_string(),