1 //! A bunch of methods and structures more or less related to resolving imports.
3 use ImportDirectiveSubclass
::*;
5 use crate::{AmbiguityError, AmbiguityKind, AmbiguityErrorMisc}
;
6 use crate::{CrateLint, Module, ModuleOrUniformRoot, PerNS, ScopeSet, ParentScope, Weak}
;
7 use crate::Determinacy
::{self, *}
;
8 use crate::Namespace
::{self, TypeNS, MacroNS}
;
9 use crate::{NameBinding, NameBindingKind, ToNameBinding, PathResult, PrivacyError}
;
10 use crate::{Resolver, ResolutionError, BindingKey, Segment, ModuleKind}
;
11 use crate::{names_to_string, module_to_string}
;
12 use crate::diagnostics
::Suggestion
;
14 use errors
::{Applicability, pluralize}
;
16 use rustc_data_structures
::ptr_key
::PtrKey
;
18 use rustc
::lint
::builtin
::BuiltinLintDiagnostics
;
19 use rustc
::lint
::builtin
::{PUB_USE_OF_PRIVATE_EXTERN_CRATE, UNUSED_IMPORTS}
;
20 use rustc
::hir
::def_id
::DefId
;
21 use rustc
::hir
::def
::{self, PartialRes, Export}
;
22 use rustc
::session
::DiagnosticMessageId
;
23 use rustc
::util
::nodemap
::FxHashSet
;
24 use rustc
::{bug, span_bug}
;
26 use syntax
::ast
::{Ident, Name, NodeId}
;
27 use syntax
::symbol
::kw
;
28 use syntax
::util
::lev_distance
::find_best_match_for_name
;
29 use syntax
::{struct_span_err, unwrap_or}
;
30 use syntax_pos
::hygiene
::ExpnId
;
31 use syntax_pos
::{MultiSpan, Span}
;
33 use rustc_error_codes
::*;
40 type Res
= def
::Res
<NodeId
>;
42 /// Contains data for specific types of import directives.
43 #[derive(Clone, Debug)]
44 pub enum ImportDirectiveSubclass
<'a
> {
46 /// `source` in `use prefix::source as target`.
48 /// `target` in `use prefix::source as target`.
50 /// Bindings to which `source` refers to.
51 source_bindings
: PerNS
<Cell
<Result
<&'a NameBinding
<'a
>, Determinacy
>>>,
52 /// Bindings introduced by `target`.
53 target_bindings
: PerNS
<Cell
<Option
<&'a NameBinding
<'a
>>>>,
54 /// `true` for `...::{self [as target]}` imports, `false` otherwise.
56 /// Did this import result from a nested import? ie. `use foo::{bar, baz};`
61 max_vis
: Cell
<ty
::Visibility
>, // The visibility of the greatest re-export.
62 // n.b. `max_vis` is only used in `finalize_import` to check for re-export errors.
71 /// One import directive.
72 #[derive(Debug, Clone)]
73 crate struct ImportDirective
<'a
> {
74 /// The ID of the `extern crate`, `UseTree` etc that imported this `ImportDirective`.
76 /// In the case where the `ImportDirective` was expanded from a "nested" use tree,
77 /// this id is the ID of the leaf tree. For example:
79 /// ```ignore (pacify the mercilous tidy)
80 /// use foo::bar::{a, b}
83 /// If this is the import directive for `foo::bar::a`, we would have the ID of the `UseTree`
84 /// for `a` in this field.
87 /// The `id` of the "root" use-kind -- this is always the same as
88 /// `id` except in the case of "nested" use trees, in which case
89 /// it will be the `id` of the root use tree. e.g., in the example
90 /// from `id`, this would be the ID of the `use foo::bar`
94 /// Span of the entire use statement.
97 /// Span of the entire use statement with attributes.
98 pub use_span_with_attributes
: Span
,
100 /// Did the use statement have any attributes?
101 pub has_attributes
: bool
,
103 /// Span of this use tree.
106 /// Span of the *root* use tree (see `root_id`).
109 pub parent_scope
: ParentScope
<'a
>,
110 pub module_path
: Vec
<Segment
>,
111 /// The resolution of `module_path`.
112 pub imported_module
: Cell
<Option
<ModuleOrUniformRoot
<'a
>>>,
113 pub subclass
: ImportDirectiveSubclass
<'a
>,
114 pub vis
: Cell
<ty
::Visibility
>,
115 pub used
: Cell
<bool
>,
118 impl<'a
> ImportDirective
<'a
> {
119 pub fn is_glob(&self) -> bool
{
120 match self.subclass { ImportDirectiveSubclass::GlobImport { .. }
=> true, _
=> false }
123 pub fn is_nested(&self) -> bool
{
124 match self.subclass
{
125 ImportDirectiveSubclass
::SingleImport { nested, .. }
=> nested
,
130 crate fn crate_lint(&self) -> CrateLint
{
131 CrateLint
::UsePath { root_id: self.root_id, root_span: self.root_span }
135 #[derive(Clone, Default, Debug)]
136 /// Records information about the resolution of a name in a namespace of a module.
137 pub struct NameResolution
<'a
> {
138 /// Single imports that may define the name in the namespace.
139 /// Import directives are arena-allocated, so it's ok to use pointers as keys.
140 single_imports
: FxHashSet
<PtrKey
<'a
, ImportDirective
<'a
>>>,
141 /// The least shadowable known binding for this name, or None if there are no known bindings.
142 pub binding
: Option
<&'a NameBinding
<'a
>>,
143 shadowed_glob
: Option
<&'a NameBinding
<'a
>>,
146 impl<'a
> NameResolution
<'a
> {
147 // Returns the binding for the name if it is known or None if it not known.
148 pub(crate) fn binding(&self) -> Option
<&'a NameBinding
<'a
>> {
149 self.binding
.and_then(|binding
| {
150 if !binding
.is_glob_import() ||
151 self.single_imports
.is_empty() { Some(binding) }
else { None }
155 crate fn add_single_import(&mut self, directive
: &'a ImportDirective
<'a
>) {
156 self.single_imports
.insert(PtrKey(directive
));
160 impl<'a
> Resolver
<'a
> {
161 crate fn resolve_ident_in_module_unadjusted(
163 module
: ModuleOrUniformRoot
<'a
>,
166 parent_scope
: &ParentScope
<'a
>,
169 ) -> Result
<&'a NameBinding
<'a
>, Determinacy
> {
170 self.resolve_ident_in_module_unadjusted_ext(
171 module
, ident
, ns
, parent_scope
, false, record_used
, path_span
172 ).map_err(|(determinacy
, _
)| determinacy
)
175 /// Attempts to resolve `ident` in namespaces `ns` of `module`.
176 /// Invariant: if `record_used` is `Some`, expansion and import resolution must be complete.
177 crate fn resolve_ident_in_module_unadjusted_ext(
179 module
: ModuleOrUniformRoot
<'a
>,
182 parent_scope
: &ParentScope
<'a
>,
183 restricted_shadowing
: bool
,
186 ) -> Result
<&'a NameBinding
<'a
>, (Determinacy
, Weak
)> {
187 let module
= match module
{
188 ModuleOrUniformRoot
::Module(module
) => module
,
189 ModuleOrUniformRoot
::CrateRootAndExternPrelude
=> {
190 assert
!(!restricted_shadowing
);
191 let binding
= self.early_resolve_ident_in_lexical_scope(
192 ident
, ScopeSet
::AbsolutePath(ns
), parent_scope
,
193 record_used
, record_used
, path_span
,
195 return binding
.map_err(|determinacy
| (determinacy
, Weak
::No
));
197 ModuleOrUniformRoot
::ExternPrelude
=> {
198 assert
!(!restricted_shadowing
);
199 return if ns
!= TypeNS
{
200 Err((Determined
, Weak
::No
))
201 } else if let Some(binding
) = self.extern_prelude_get(ident
, !record_used
) {
203 } else if !self.graph_root
.unexpanded_invocations
.borrow().is_empty() {
204 // Macro-expanded `extern crate` items can add names to extern prelude.
205 Err((Undetermined
, Weak
::No
))
207 Err((Determined
, Weak
::No
))
210 ModuleOrUniformRoot
::CurrentScope
=> {
211 assert
!(!restricted_shadowing
);
213 if ident
.name
== kw
::Crate
||
214 ident
.name
== kw
::DollarCrate
{
215 let module
= self.resolve_crate_root(ident
);
216 let binding
= (module
, ty
::Visibility
::Public
,
217 module
.span
, ExpnId
::root())
218 .to_name_binding(self.arenas
);
220 } else if ident
.name
== kw
::Super
||
221 ident
.name
== kw
::SelfLower
{
222 // FIXME: Implement these with renaming requirements so that e.g.
223 // `use super;` doesn't work, but `use super as name;` does.
224 // Fall through here to get an error from `early_resolve_...`.
228 let scopes
= ScopeSet
::All(ns
, true);
229 let binding
= self.early_resolve_ident_in_lexical_scope(
230 ident
, scopes
, parent_scope
, record_used
, record_used
, path_span
232 return binding
.map_err(|determinacy
| (determinacy
, Weak
::No
));
236 let key
= self.new_key(ident
, ns
);
237 let resolution
= self.resolution(module
, key
)
239 .map_err(|_
| (Determined
, Weak
::No
))?
; // This happens when there is a cycle of imports.
241 if let Some(binding
) = resolution
.binding
{
242 if !restricted_shadowing
&& binding
.expansion
!= ExpnId
::root() {
243 if let NameBindingKind
::Res(_
, true) = binding
.kind
{
244 self.macro_expanded_macro_export_errors
.insert((path_span
, binding
.span
));
249 let check_usable
= |this
: &mut Self, binding
: &'a NameBinding
<'a
>| {
250 if let Some(blacklisted_binding
) = this
.blacklisted_binding
{
251 if ptr
::eq(binding
, blacklisted_binding
) {
252 return Err((Determined
, Weak
::No
));
255 // `extern crate` are always usable for backwards compatibility, see issue #37020,
256 // remove this together with `PUB_USE_OF_PRIVATE_EXTERN_CRATE`.
257 let usable
= this
.is_accessible_from(binding
.vis
, parent_scope
.module
) ||
258 binding
.is_extern_crate();
259 if usable { Ok(binding) }
else { Err((Determined, Weak::No)) }
263 return resolution
.binding
.and_then(|binding
| {
264 // If the primary binding is blacklisted, search further and return the shadowed
265 // glob binding if it exists. What we really want here is having two separate
266 // scopes in a module - one for non-globs and one for globs, but until that's done
267 // use this hack to avoid inconsistent resolution ICEs during import validation.
268 if let Some(blacklisted_binding
) = self.blacklisted_binding
{
269 if ptr
::eq(binding
, blacklisted_binding
) {
270 return resolution
.shadowed_glob
;
274 }).ok_or((Determined
, Weak
::No
)).and_then(|binding
| {
275 if self.last_import_segment
&& check_usable(self, binding
).is_err() {
276 Err((Determined
, Weak
::No
))
278 self.record_use(ident
, ns
, binding
, restricted_shadowing
);
280 if let Some(shadowed_glob
) = resolution
.shadowed_glob
{
281 // Forbid expanded shadowing to avoid time travel.
282 if restricted_shadowing
&&
283 binding
.expansion
!= ExpnId
::root() &&
284 binding
.res() != shadowed_glob
.res() {
285 self.ambiguity_errors
.push(AmbiguityError
{
286 kind
: AmbiguityKind
::GlobVsExpanded
,
290 misc1
: AmbiguityErrorMisc
::None
,
291 misc2
: AmbiguityErrorMisc
::None
,
296 if !self.is_accessible_from(binding
.vis
, parent_scope
.module
) &&
297 // Remove this together with `PUB_USE_OF_PRIVATE_EXTERN_CRATE`
298 !(self.last_import_segment
&& binding
.is_extern_crate()) {
299 self.privacy_errors
.push(PrivacyError(path_span
, ident
, binding
));
307 // Items and single imports are not shadowable, if we have one, then it's determined.
308 if let Some(binding
) = resolution
.binding
{
309 if !binding
.is_glob_import() {
310 return check_usable(self, binding
);
314 // --- From now on we either have a glob resolution or no resolution. ---
316 // Check if one of single imports can still define the name,
317 // if it can then our result is not determined and can be invalidated.
318 for single_import
in &resolution
.single_imports
{
319 if !self.is_accessible_from(single_import
.vis
.get(), parent_scope
.module
) {
322 let module
= unwrap_or
!(single_import
.imported_module
.get(),
323 return Err((Undetermined
, Weak
::No
)));
324 let ident
= match single_import
.subclass
{
325 SingleImport { source, .. }
=> source
,
328 match self.resolve_ident_in_module(module
, ident
, ns
, &single_import
.parent_scope
,
330 Err(Determined
) => continue,
331 Ok(binding
) if !self.is_accessible_from(
332 binding
.vis
, single_import
.parent_scope
.module
334 Ok(_
) | Err(Undetermined
) => return Err((Undetermined
, Weak
::No
)),
338 // So we have a resolution that's from a glob import. This resolution is determined
339 // if it cannot be shadowed by some new item/import expanded from a macro.
340 // This happens either if there are no unexpanded macros, or expanded names cannot
341 // shadow globs (that happens in macro namespace or with restricted shadowing).
343 // Additionally, any macro in any module can plant names in the root module if it creates
344 // `macro_export` macros, so the root module effectively has unresolved invocations if any
345 // module has unresolved invocations.
346 // However, it causes resolution/expansion to stuck too often (#53144), so, to make
347 // progress, we have to ignore those potential unresolved invocations from other modules
348 // and prohibit access to macro-expanded `macro_export` macros instead (unless restricted
349 // shadowing is enabled, see `macro_expanded_macro_export_errors`).
350 let unexpanded_macros
= !module
.unexpanded_invocations
.borrow().is_empty();
351 if let Some(binding
) = resolution
.binding
{
352 if !unexpanded_macros
|| ns
== MacroNS
|| restricted_shadowing
{
353 return check_usable(self, binding
);
355 return Err((Undetermined
, Weak
::No
));
359 // --- From now on we have no resolution. ---
361 // Now we are in situation when new item/import can appear only from a glob or a macro
362 // expansion. With restricted shadowing names from globs and macro expansions cannot
363 // shadow names from outer scopes, so we can freely fallback from module search to search
364 // in outer scopes. For `early_resolve_ident_in_lexical_scope` to continue search in outer
365 // scopes we return `Undetermined` with `Weak::Yes`.
367 // Check if one of unexpanded macros can still define the name,
368 // if it can then our "no resolution" result is not determined and can be invalidated.
369 if unexpanded_macros
{
370 return Err((Undetermined
, Weak
::Yes
));
373 // Check if one of glob imports can still define the name,
374 // if it can then our "no resolution" result is not determined and can be invalidated.
375 for glob_import
in module
.globs
.borrow().iter() {
376 if !self.is_accessible_from(glob_import
.vis
.get(), parent_scope
.module
) {
379 let module
= match glob_import
.imported_module
.get() {
380 Some(ModuleOrUniformRoot
::Module(module
)) => module
,
382 None
=> return Err((Undetermined
, Weak
::Yes
)),
384 let tmp_parent_scope
;
385 let (mut adjusted_parent_scope
, mut ident
) = (parent_scope
, ident
.modern());
386 match ident
.span
.glob_adjust(module
.expansion
, glob_import
.span
) {
389 ParentScope { module: self.macro_def_scope(def), ..*parent_scope }
;
390 adjusted_parent_scope
= &tmp_parent_scope
;
395 let result
= self.resolve_ident_in_module_unadjusted(
396 ModuleOrUniformRoot
::Module(module
),
399 adjusted_parent_scope
,
405 Err(Determined
) => continue,
406 Ok(binding
) if !self.is_accessible_from(
407 binding
.vis
, glob_import
.parent_scope
.module
409 Ok(_
) | Err(Undetermined
) => return Err((Undetermined
, Weak
::Yes
)),
413 // No resolution and no one else can define the name - determinate error.
414 Err((Determined
, Weak
::No
))
417 // Given a binding and an import directive that resolves to it,
418 // return the corresponding binding defined by the import directive.
419 crate fn import(&self, binding
: &'a NameBinding
<'a
>, directive
: &'a ImportDirective
<'a
>)
420 -> &'a NameBinding
<'a
> {
421 let vis
= if binding
.pseudo_vis().is_at_least(directive
.vis
.get(), self) ||
422 // cf. `PUB_USE_OF_PRIVATE_EXTERN_CRATE`
423 !directive
.is_glob() && binding
.is_extern_crate() {
429 if let GlobImport { ref max_vis, .. }
= directive
.subclass
{
430 if vis
== directive
.vis
.get() || vis
.is_at_least(max_vis
.get(), self) {
435 self.arenas
.alloc_name_binding(NameBinding
{
436 kind
: NameBindingKind
::Import
{
439 used
: Cell
::new(false),
442 span
: directive
.span
,
444 expansion
: directive
.parent_scope
.expansion
,
448 // Define the name or return the existing binding if there is a collision.
453 binding
: &'a NameBinding
<'a
>,
454 ) -> Result
<(), &'a NameBinding
<'a
>> {
455 let res
= binding
.res();
456 self.check_reserved_macro_name(key
.ident
, res
);
457 self.set_binding_parent_module(binding
, module
);
458 self.update_resolution(module
, key
, |this
, resolution
| {
459 if let Some(old_binding
) = resolution
.binding
{
461 // Do not override real bindings with `Res::Err`s from error recovery.
464 match (old_binding
.is_glob_import(), binding
.is_glob_import()) {
466 if res
!= old_binding
.res() {
467 resolution
.binding
= Some(this
.ambiguity(AmbiguityKind
::GlobVsGlob
,
468 old_binding
, binding
));
469 } else if !old_binding
.vis
.is_at_least(binding
.vis
, &*this
) {
470 // We are glob-importing the same item but with greater visibility.
471 resolution
.binding
= Some(binding
);
474 (old_glob @
true, false) | (old_glob @
false, true) => {
475 let (glob_binding
, nonglob_binding
) = if old_glob
{
476 (old_binding
, binding
)
478 (binding
, old_binding
)
480 if glob_binding
.res() != nonglob_binding
.res()
481 && key
.ns
== MacroNS
&& nonglob_binding
.expansion
!= ExpnId
::root()
483 resolution
.binding
= Some(this
.ambiguity(
484 AmbiguityKind
::GlobVsExpanded
,
489 resolution
.binding
= Some(nonglob_binding
);
491 resolution
.shadowed_glob
= Some(glob_binding
);
494 if let (&NameBindingKind
::Res(_
, true), &NameBindingKind
::Res(_
, true)) =
495 (&old_binding
.kind
, &binding
.kind
) {
497 this
.session
.struct_span_err(
499 &format
!("a macro named `{}` has already been exported", key
.ident
),
501 .span_label(binding
.span
, format
!("`{}` already exported", key
.ident
))
502 .span_note(old_binding
.span
, "previous macro export is now shadowed")
505 resolution
.binding
= Some(binding
);
507 return Err(old_binding
);
512 resolution
.binding
= Some(binding
);
520 &self, kind
: AmbiguityKind
,
521 primary_binding
: &'a NameBinding
<'a
>,
522 secondary_binding
: &'a NameBinding
<'a
>,
523 ) -> &'a NameBinding
<'a
> {
524 self.arenas
.alloc_name_binding(NameBinding
{
525 ambiguity
: Some((secondary_binding
, kind
)),
526 ..primary_binding
.clone()
530 // Use `f` to mutate the resolution of the name in the module.
531 // If the resolution becomes a success, define it in the module's glob importers.
532 fn update_resolution
<T
, F
>(
538 where F
: FnOnce(&mut Resolver
<'a
>, &mut NameResolution
<'a
>) -> T
540 // Ensure that `resolution` isn't borrowed when defining in the module's glob importers,
541 // during which the resolution might end up getting re-defined via a glob cycle.
543 let resolution
= &mut *self.resolution(module
, key
).borrow_mut();
544 let old_binding
= resolution
.binding();
546 let t
= f(self, resolution
);
548 match resolution
.binding() {
549 _
if old_binding
.is_some() => return t
,
551 Some(binding
) => match old_binding
{
552 Some(old_binding
) if ptr
::eq(old_binding
, binding
) => return t
,
558 // Define `binding` in `module`s glob importers.
559 for directive
in module
.glob_importers
.borrow_mut().iter() {
560 let mut ident
= key
.ident
;
561 let scope
= match ident
.span
.reverse_glob_adjust(module
.expansion
, directive
.span
) {
562 Some(Some(def
)) => self.macro_def_scope(def
),
563 Some(None
) => directive
.parent_scope
.module
,
566 if self.is_accessible_from(binding
.vis
, scope
) {
567 let imported_binding
= self.import(binding
, directive
);
568 let key
= BindingKey { ident, ..key }
;
569 let _
= self.try_define(directive
.parent_scope
.module
, key
, imported_binding
);
576 // Define a "dummy" resolution containing a Res::Err as a placeholder for a
578 fn import_dummy_binding(&mut self, directive
: &'a ImportDirective
<'a
>) {
579 if let SingleImport { target, .. }
= directive
.subclass
{
580 let dummy_binding
= self.dummy_binding
;
581 let dummy_binding
= self.import(dummy_binding
, directive
);
582 self.per_ns(|this
, ns
| {
583 let key
= this
.new_key(target
, ns
);
584 let _
= this
.try_define(directive
.parent_scope
.module
, key
, dummy_binding
);
585 // Consider erroneous imports used to avoid duplicate diagnostics.
586 this
.record_use(target
, ns
, dummy_binding
, false);
592 /// An error that may be transformed into a diagnostic later. Used to combine multiple unresolved
593 /// import errors within the same use tree into a single diagnostic.
594 #[derive(Debug, Clone)]
595 struct UnresolvedImportError
{
597 label
: Option
<String
>,
599 suggestion
: Option
<Suggestion
>,
602 pub struct ImportResolver
<'a
, 'b
> {
603 pub r
: &'a
mut Resolver
<'b
>,
606 impl<'a
, 'b
> ty
::DefIdTree
for &'a ImportResolver
<'a
, 'b
> {
607 fn parent(self, id
: DefId
) -> Option
<DefId
> {
612 impl<'a
, 'b
> ImportResolver
<'a
, 'b
> {
615 // This is a fixed-point algorithm. We resolve imports until our efforts
616 // are stymied by an unresolved import; then we bail out of the current
617 // module and continue. We terminate successfully once no more imports
618 // remain or unsuccessfully when no forward progress in resolving imports
621 /// Resolves all imports for the crate. This method performs the fixed-
623 pub fn resolve_imports(&mut self) {
624 let mut prev_num_indeterminates
= self.r
.indeterminate_imports
.len() + 1;
625 while self.r
.indeterminate_imports
.len() < prev_num_indeterminates
{
626 prev_num_indeterminates
= self.r
.indeterminate_imports
.len();
627 for import
in mem
::take(&mut self.r
.indeterminate_imports
) {
628 match self.resolve_import(&import
) {
629 true => self.r
.determined_imports
.push(import
),
630 false => self.r
.indeterminate_imports
.push(import
),
636 pub fn finalize_imports(&mut self) {
637 for module
in self.r
.arenas
.local_modules().iter() {
638 self.finalize_resolutions_in(module
);
641 let mut seen_spans
= FxHashSet
::default();
642 let mut errors
= vec
![];
643 let mut prev_root_id
: NodeId
= NodeId
::from_u32(0);
644 let determined_imports
= mem
::take(&mut self.r
.determined_imports
);
645 let indeterminate_imports
= mem
::take(&mut self.r
.indeterminate_imports
);
647 for (is_indeterminate
, import
) in determined_imports
650 .chain(indeterminate_imports
.into_iter().map(|i
| (true, i
)))
652 if let Some(err
) = self.finalize_import(import
) {
654 if let SingleImport { source, ref source_bindings, .. }
= import
.subclass
{
655 if source
.name
== kw
::SelfLower
{
656 // Silence `unresolved import` error if E0429 is already emitted
657 if let Err(Determined
) = source_bindings
.value_ns
.get() {
663 // If the error is a single failed import then create a "fake" import
664 // resolution for it so that later resolve stages won't complain.
665 self.r
.import_dummy_binding(import
);
666 if prev_root_id
.as_u32() != 0
667 && prev_root_id
.as_u32() != import
.root_id
.as_u32()
668 && !errors
.is_empty() {
669 // In the case of a new import line, throw a diagnostic message
670 // for the previous line.
671 self.throw_unresolved_import_error(errors
, None
);
674 if seen_spans
.insert(err
.span
) {
675 let path
= import_path_to_string(
676 &import
.module_path
.iter().map(|seg
| seg
.ident
).collect
::<Vec
<_
>>(),
680 errors
.push((path
, err
));
681 prev_root_id
= import
.root_id
;
683 } else if is_indeterminate
{
684 // Consider erroneous imports used to avoid duplicate diagnostics.
685 self.r
.used_imports
.insert((import
.id
, TypeNS
));
686 let path
= import_path_to_string(
687 &import
.module_path
.iter().map(|seg
| seg
.ident
).collect
::<Vec
<_
>>(),
691 let err
= UnresolvedImportError
{
697 errors
.push((path
, err
));
701 if !errors
.is_empty() {
702 self.throw_unresolved_import_error(errors
.clone(), None
);
706 fn throw_unresolved_import_error(
708 errors
: Vec
<(String
, UnresolvedImportError
)>,
709 span
: Option
<MultiSpan
>,
711 /// Upper limit on the number of `span_label` messages.
712 const MAX_LABEL_COUNT
: usize = 10;
714 let (span
, msg
) = if errors
.is_empty() {
715 (span
.unwrap(), "unresolved import".to_string())
717 let span
= MultiSpan
::from_spans(
720 .map(|(_
, err
)| err
.span
)
726 .map(|(path
, _
)| format
!("`{}`", path
))
727 .collect
::<Vec
<_
>>();
730 "unresolved import{} {}",
731 pluralize
!(paths
.len()),
738 let mut diag
= struct_span_err
!(self.r
.session
, span
, E0432
, "{}", &msg
);
740 if let Some((_
, UnresolvedImportError { note, .. }
)) = errors
.iter().last() {
741 for message
in note
{
746 for (_
, err
) in errors
.into_iter().take(MAX_LABEL_COUNT
) {
747 if let Some(label
) = err
.label
{
748 diag
.span_label(err
.span
, label
);
751 if let Some((suggestions
, msg
, applicability
)) = err
.suggestion
{
752 diag
.multipart_suggestion(&msg
, suggestions
, applicability
);
759 /// Attempts to resolve the given import, returning true if its resolution is determined.
760 /// If successful, the resolved bindings are written into the module.
761 fn resolve_import(&mut self, directive
: &'b ImportDirective
<'b
>) -> bool
{
763 "(resolving import for module) resolving import `{}::...` in `{}`",
764 Segment
::names_to_string(&directive
.module_path
),
765 module_to_string(directive
.parent_scope
.module
).unwrap_or_else(|| "???".to_string()),
768 let module
= if let Some(module
) = directive
.imported_module
.get() {
771 // For better failure detection, pretend that the import will
772 // not define any names while resolving its module path.
773 let orig_vis
= directive
.vis
.replace(ty
::Visibility
::Invisible
);
774 let path_res
= self.r
.resolve_path(
775 &directive
.module_path
,
777 &directive
.parent_scope
,
780 directive
.crate_lint(),
782 directive
.vis
.set(orig_vis
);
785 PathResult
::Module(module
) => module
,
786 PathResult
::Indeterminate
=> return false,
787 PathResult
::NonModule(..) | PathResult
::Failed { .. }
=> return true,
791 directive
.imported_module
.set(Some(module
));
792 let (source
, target
, source_bindings
, target_bindings
, type_ns_only
) =
793 match directive
.subclass
{
794 SingleImport
{ source
, target
, ref source_bindings
,
795 ref target_bindings
, type_ns_only
, .. } =>
796 (source
, target
, source_bindings
, target_bindings
, type_ns_only
),
797 GlobImport { .. }
=> {
798 self.resolve_glob_import(directive
);
804 let mut indeterminate
= false;
805 self.r
.per_ns(|this
, ns
| if !type_ns_only
|| ns
== TypeNS
{
806 if let Err(Undetermined
) = source_bindings
[ns
].get() {
807 // For better failure detection, pretend that the import will
808 // not define any names while resolving its module path.
809 let orig_vis
= directive
.vis
.replace(ty
::Visibility
::Invisible
);
810 let binding
= this
.resolve_ident_in_module(
811 module
, source
, ns
, &directive
.parent_scope
, false, directive
.span
813 directive
.vis
.set(orig_vis
);
815 source_bindings
[ns
].set(binding
);
820 let parent
= directive
.parent_scope
.module
;
821 match source_bindings
[ns
].get() {
822 Err(Undetermined
) => indeterminate
= true,
823 // Don't update the resolution, because it was never added.
824 Err(Determined
) if target
.name
== kw
::Underscore
=> {}
826 let key
= this
.new_key(target
, ns
);
827 this
.update_resolution(parent
, key
, |_
, resolution
| {
828 resolution
.single_imports
.remove(&PtrKey(directive
));
831 Ok(binding
) if !binding
.is_importable() => {
832 let msg
= format
!("`{}` is not directly importable", target
);
833 struct_span_err
!(this
.session
, directive
.span
, E0253
, "{}", &msg
)
834 .span_label(directive
.span
, "cannot be imported directly")
836 // Do not import this illegal binding. Import a dummy binding and pretend
837 // everything is fine
838 this
.import_dummy_binding(directive
);
841 let imported_binding
= this
.import(binding
, directive
);
842 target_bindings
[ns
].set(Some(imported_binding
));
843 this
.define(parent
, target
, ns
, imported_binding
);
851 /// Performs final import resolution, consistency checks and error reporting.
853 /// Optionally returns an unresolved import error. This error is buffered and used to
854 /// consolidate multiple unresolved import errors into a single diagnostic.
857 directive
: &'b ImportDirective
<'b
>
858 ) -> Option
<UnresolvedImportError
> {
859 let orig_vis
= directive
.vis
.replace(ty
::Visibility
::Invisible
);
860 let prev_ambiguity_errors_len
= self.r
.ambiguity_errors
.len();
861 let path_res
= self.r
.resolve_path(
862 &directive
.module_path
,
864 &directive
.parent_scope
,
867 directive
.crate_lint(),
869 let no_ambiguity
= self.r
.ambiguity_errors
.len() == prev_ambiguity_errors_len
;
870 directive
.vis
.set(orig_vis
);
871 if let PathResult
::Failed { .. }
| PathResult
::NonModule(..) = path_res
{
872 // Consider erroneous imports used to avoid duplicate diagnostics.
873 self.r
.used_imports
.insert((directive
.id
, TypeNS
));
875 let module
= match path_res
{
876 PathResult
::Module(module
) => {
877 // Consistency checks, analogous to `finalize_macro_resolutions`.
878 if let Some(initial_module
) = directive
.imported_module
.get() {
879 if !ModuleOrUniformRoot
::same_def(module
, initial_module
) && no_ambiguity
{
880 span_bug
!(directive
.span
, "inconsistent resolution for an import");
883 if self.r
.privacy_errors
.is_empty() {
884 let msg
= "cannot determine resolution for the import";
885 let msg_note
= "import resolution is stuck, try simplifying other imports";
886 self.r
.session
.struct_span_err(directive
.span
, msg
).note(msg_note
).emit();
892 PathResult
::Failed { is_error_from_last_segment: false, span, label, suggestion }
=> {
894 assert
!(directive
.imported_module
.get().is_none());
895 self.r
.report_error(span
, ResolutionError
::FailedToResolve
{
902 PathResult
::Failed { is_error_from_last_segment: true, span, label, suggestion }
=> {
904 assert
!(directive
.imported_module
.get().is_none());
905 let err
= match self.make_path_suggestion(
907 directive
.module_path
.clone(),
908 &directive
.parent_scope
,
910 Some((suggestion
, note
)) => {
911 UnresolvedImportError
{
916 vec
![(span
, Segment
::names_to_string(&suggestion
))],
917 String
::from("a similar path exists"),
918 Applicability
::MaybeIncorrect
,
923 UnresolvedImportError
{
935 PathResult
::NonModule(path_res
) if path_res
.base_res() == Res
::Err
=> {
937 assert
!(directive
.imported_module
.get().is_none());
939 // The error was already reported earlier.
942 PathResult
::Indeterminate
| PathResult
::NonModule(..) => unreachable
!(),
945 let (ident
, target
, source_bindings
, target_bindings
, type_ns_only
) =
946 match directive
.subclass
{
947 SingleImport
{ source
, target
, ref source_bindings
,
948 ref target_bindings
, type_ns_only
, .. } =>
949 (source
, target
, source_bindings
, target_bindings
, type_ns_only
),
950 GlobImport { is_prelude, ref max_vis }
=> {
951 if directive
.module_path
.len() <= 1 {
952 // HACK(eddyb) `lint_if_path_starts_with_module` needs at least
953 // 2 segments, so the `resolve_path` above won't trigger it.
954 let mut full_path
= directive
.module_path
.clone();
955 full_path
.push(Segment
::from_ident(Ident
::invalid()));
956 self.r
.lint_if_path_starts_with_module(
957 directive
.crate_lint(),
964 if let ModuleOrUniformRoot
::Module(module
) = module
{
965 if module
.def_id() == directive
.parent_scope
.module
.def_id() {
966 // Importing a module into itself is not allowed.
967 return Some(UnresolvedImportError
{
968 span
: directive
.span
,
969 label
: Some(String
::from("cannot glob-import a module into itself")),
976 max_vis
.get() != ty
::Visibility
::Invisible
&& // Allow empty globs.
977 !max_vis
.get().is_at_least(directive
.vis
.get(), &*self) {
979 "glob import doesn't reexport anything because no candidate is public enough";
980 self.r
.lint_buffer
.buffer_lint(
981 UNUSED_IMPORTS
, directive
.id
, directive
.span
, msg
,
989 let mut all_ns_err
= true;
990 self.r
.per_ns(|this
, ns
| if !type_ns_only
|| ns
== TypeNS
{
991 let orig_vis
= directive
.vis
.replace(ty
::Visibility
::Invisible
);
992 let orig_blacklisted_binding
=
993 mem
::replace(&mut this
.blacklisted_binding
, target_bindings
[ns
].get());
994 let orig_last_import_segment
= mem
::replace(&mut this
.last_import_segment
, true);
995 let binding
= this
.resolve_ident_in_module(
996 module
, ident
, ns
, &directive
.parent_scope
, true, directive
.span
998 this
.last_import_segment
= orig_last_import_segment
;
999 this
.blacklisted_binding
= orig_blacklisted_binding
;
1000 directive
.vis
.set(orig_vis
);
1004 // Consistency checks, analogous to `finalize_macro_resolutions`.
1005 let initial_res
= source_bindings
[ns
].get().map(|initial_binding
| {
1007 if let Some(target_binding
) = target_bindings
[ns
].get() {
1008 // Note that as_str() de-gensyms the Symbol
1009 if target
.name
.as_str() == "_" &&
1010 initial_binding
.is_extern_crate() && !initial_binding
.is_import() {
1011 this
.record_use(ident
, ns
, target_binding
,
1012 directive
.module_path
.is_empty());
1015 initial_binding
.res()
1017 let res
= binding
.res();
1018 if let Ok(initial_res
) = initial_res
{
1019 if res
!= initial_res
&& this
.ambiguity_errors
.is_empty() {
1020 span_bug
!(directive
.span
, "inconsistent resolution for an import");
1023 if res
!= Res
::Err
&&
1024 this
.ambiguity_errors
.is_empty() && this
.privacy_errors
.is_empty() {
1025 let msg
= "cannot determine resolution for the import";
1027 "import resolution is stuck, try simplifying other imports";
1028 this
.session
.struct_span_err(directive
.span
, msg
).note(msg_note
).emit();
1033 // FIXME: This assert may fire if public glob is later shadowed by a private
1034 // single import (see test `issue-55884-2.rs`). In theory single imports should
1035 // always block globs, even if they are not yet resolved, so that this kind of
1036 // self-inconsistent resolution never happens.
1037 // Reenable the assert when the issue is fixed.
1038 // assert!(result[ns].get().is_err());
1044 let mut all_ns_failed
= true;
1045 self.r
.per_ns(|this
, ns
| if !type_ns_only
|| ns
== TypeNS
{
1046 let binding
= this
.resolve_ident_in_module(
1047 module
, ident
, ns
, &directive
.parent_scope
, true, directive
.span
1049 if binding
.is_ok() {
1050 all_ns_failed
= false;
1054 return if all_ns_failed
{
1055 let resolutions
= match module
{
1056 ModuleOrUniformRoot
::Module(module
) =>
1057 Some(self.r
.resolutions(module
).borrow()),
1060 let resolutions
= resolutions
.as_ref().into_iter().flat_map(|r
| r
.iter());
1061 let names
= resolutions
.filter_map(|(BindingKey { ident: i, .. }
, resolution
)| {
1062 if *i
== ident { return None; }
// Never suggest the same name
1063 match *resolution
.borrow() {
1064 NameResolution { binding: Some(name_binding), .. }
=> {
1065 match name_binding
.kind
{
1066 NameBindingKind
::Import { binding, .. }
=> {
1067 match binding
.kind
{
1068 // Never suggest the name that has binding error
1069 // i.e., the name that cannot be previously resolved
1070 NameBindingKind
::Res(Res
::Err
, _
) => return None
,
1077 NameResolution { ref single_imports, .. }
1078 if single_imports
.is_empty() => None
,
1083 let lev_suggestion
= find_best_match_for_name(names
, &ident
.as_str(), None
)
1085 (vec
![(ident
.span
, suggestion
.to_string())],
1086 String
::from("a similar name exists in the module"),
1087 Applicability
::MaybeIncorrect
)
1090 let (suggestion
, note
) = match self.check_for_module_export_macro(
1091 directive
, module
, ident
,
1093 Some((suggestion
, note
)) => (suggestion
.or(lev_suggestion
), note
),
1094 _
=> (lev_suggestion
, Vec
::new()),
1097 let label
= match module
{
1098 ModuleOrUniformRoot
::Module(module
) => {
1099 let module_str
= module_to_string(module
);
1100 if let Some(module_str
) = module_str
{
1101 format
!("no `{}` in `{}`", ident
, module_str
)
1103 format
!("no `{}` in the root", ident
)
1107 if !ident
.is_path_segment_keyword() {
1108 format
!("no `{}` external crate", ident
)
1110 // HACK(eddyb) this shows up for `self` & `super`, which
1111 // should work instead - for now keep the same error message.
1112 format
!("no `{}` in the root", ident
)
1117 Some(UnresolvedImportError
{
1118 span
: directive
.span
,
1124 // `resolve_ident_in_module` reported a privacy error.
1125 self.r
.import_dummy_binding(directive
);
1130 let mut reexport_error
= None
;
1131 let mut any_successful_reexport
= false;
1132 self.r
.per_ns(|this
, ns
| {
1133 if let Ok(binding
) = source_bindings
[ns
].get() {
1134 let vis
= directive
.vis
.get();
1135 if !binding
.pseudo_vis().is_at_least(vis
, &*this
) {
1136 reexport_error
= Some((ns
, binding
));
1138 any_successful_reexport
= true;
1143 // All namespaces must be re-exported with extra visibility for an error to occur.
1144 if !any_successful_reexport
{
1145 let (ns
, binding
) = reexport_error
.unwrap();
1146 if ns
== TypeNS
&& binding
.is_extern_crate() {
1147 let msg
= format
!("extern crate `{}` is private, and cannot be \
1148 re-exported (error E0365), consider declaring with \
1151 self.r
.lint_buffer
.buffer_lint(PUB_USE_OF_PRIVATE_EXTERN_CRATE
,
1155 } else if ns
== TypeNS
{
1156 struct_span_err
!(self.r
.session
, directive
.span
, E0365
,
1157 "`{}` is private, and cannot be re-exported", ident
)
1158 .span_label(directive
.span
, format
!("re-export of private `{}`", ident
))
1159 .note(&format
!("consider declaring type or module `{}` with `pub`", ident
))
1162 let msg
= format
!("`{}` is private, and cannot be re-exported", ident
);
1163 let note_msg
= format
!(
1164 "consider marking `{}` as `pub` in the imported module",
1167 struct_span_err
!(self.r
.session
, directive
.span
, E0364
, "{}", &msg
)
1168 .span_note(directive
.span
, ¬e_msg
)
1173 if directive
.module_path
.len() <= 1 {
1174 // HACK(eddyb) `lint_if_path_starts_with_module` needs at least
1175 // 2 segments, so the `resolve_path` above won't trigger it.
1176 let mut full_path
= directive
.module_path
.clone();
1177 full_path
.push(Segment
::from_ident(ident
));
1178 self.r
.per_ns(|this
, ns
| {
1179 if let Ok(binding
) = source_bindings
[ns
].get() {
1180 this
.lint_if_path_starts_with_module(
1181 directive
.crate_lint(),
1190 // Record what this import resolves to for later uses in documentation,
1191 // this may resolve to either a value or a type, but for documentation
1192 // purposes it's good enough to just favor one over the other.
1193 self.r
.per_ns(|this
, ns
| if let Some(binding
) = source_bindings
[ns
].get().ok() {
1194 this
.import_res_map
.entry(directive
.id
).or_default()[ns
] = Some(binding
.res());
1197 self.check_for_redundant_imports(
1205 debug
!("(resolving single import) successfully resolved import");
1209 fn check_for_redundant_imports(
1212 directive
: &'b ImportDirective
<'b
>,
1213 source_bindings
: &PerNS
<Cell
<Result
<&'b NameBinding
<'b
>, Determinacy
>>>,
1214 target_bindings
: &PerNS
<Cell
<Option
<&'b NameBinding
<'b
>>>>,
1217 // Skip if the import was produced by a macro.
1218 if directive
.parent_scope
.expansion
!= ExpnId
::root() {
1222 // Skip if we are inside a named module (in contrast to an anonymous
1223 // module defined by a block).
1224 if let ModuleKind
::Def(..) = directive
.parent_scope
.module
.kind
{
1228 let mut is_redundant
= PerNS
{
1234 let mut redundant_span
= PerNS
{
1240 self.r
.per_ns(|this
, ns
| if let Some(binding
) = source_bindings
[ns
].get().ok() {
1241 if binding
.res() == Res
::Err
{
1245 let orig_blacklisted_binding
= mem
::replace(
1246 &mut this
.blacklisted_binding
,
1247 target_bindings
[ns
].get()
1250 match this
.early_resolve_ident_in_lexical_scope(
1252 ScopeSet
::All(ns
, false),
1253 &directive
.parent_scope
,
1258 Ok(other_binding
) => {
1259 is_redundant
[ns
] = Some(
1260 binding
.res() == other_binding
.res()
1261 && !other_binding
.is_ambiguity()
1263 redundant_span
[ns
] =
1264 Some((other_binding
.span
, other_binding
.is_import()));
1266 Err(_
) => is_redundant
[ns
] = Some(false)
1269 this
.blacklisted_binding
= orig_blacklisted_binding
;
1272 if !is_redundant
.is_empty() &&
1273 is_redundant
.present_items().all(|is_redundant
| is_redundant
)
1275 let mut redundant_spans
: Vec
<_
> = redundant_span
.present_items().collect();
1276 redundant_spans
.sort();
1277 redundant_spans
.dedup();
1278 self.r
.lint_buffer
.buffer_lint_with_diagnostic(
1282 &format
!("the item `{}` is imported redundantly", ident
),
1283 BuiltinLintDiagnostics
::RedundantImport(redundant_spans
, ident
),
1288 fn resolve_glob_import(&mut self, directive
: &'b ImportDirective
<'b
>) {
1289 let module
= match directive
.imported_module
.get().unwrap() {
1290 ModuleOrUniformRoot
::Module(module
) => module
,
1292 self.r
.session
.span_err(directive
.span
, "cannot glob-import all possible crates");
1297 if module
.is_trait() {
1298 self.r
.session
.span_err(directive
.span
, "items in traits are not importable.");
1300 } else if module
.def_id() == directive
.parent_scope
.module
.def_id() {
1302 } else if let GlobImport { is_prelude: true, .. }
= directive
.subclass
{
1303 self.r
.prelude
= Some(module
);
1307 // Add to module's glob_importers
1308 module
.glob_importers
.borrow_mut().push(directive
);
1310 // Ensure that `resolutions` isn't borrowed during `try_define`,
1311 // since it might get updated via a glob cycle.
1312 let bindings
= self.r
.resolutions(module
).borrow().iter().filter_map(|(key
, resolution
)| {
1313 resolution
.borrow().binding().map(|binding
| (*key
, binding
))
1314 }).collect
::<Vec
<_
>>();
1315 for (mut key
, binding
) in bindings
{
1316 let scope
= match key
.ident
.span
.reverse_glob_adjust(module
.expansion
, directive
.span
) {
1317 Some(Some(def
)) => self.r
.macro_def_scope(def
),
1318 Some(None
) => directive
.parent_scope
.module
,
1321 if self.r
.is_accessible_from(binding
.pseudo_vis(), scope
) {
1322 let imported_binding
= self.r
.import(binding
, directive
);
1323 let _
= self.r
.try_define(directive
.parent_scope
.module
, key
, imported_binding
);
1327 // Record the destination of this import
1328 self.r
.record_partial_res(directive
.id
, PartialRes
::new(module
.res().unwrap()));
1331 // Miscellaneous post-processing, including recording re-exports,
1332 // reporting conflicts, and reporting unresolved imports.
1333 fn finalize_resolutions_in(&mut self, module
: Module
<'b
>) {
1334 // Since import resolution is finished, globs will not define any more names.
1335 *module
.globs
.borrow_mut() = Vec
::new();
1337 let mut reexports
= Vec
::new();
1339 module
.for_each_child(self.r
, |this
, ident
, ns
, binding
| {
1340 // Filter away ambiguous imports and anything that has def-site
1342 // FIXME: Implement actual cross-crate hygiene.
1343 let is_good_import
= binding
.is_import() && !binding
.is_ambiguity()
1344 && !ident
.span
.from_expansion();
1345 if is_good_import
|| binding
.is_macro_def() {
1346 let res
= binding
.res();
1347 if res
!= Res
::Err
{
1348 if let Some(def_id
) = res
.opt_def_id() {
1349 if !def_id
.is_local() {
1350 this
.cstore().export_macros_untracked(def_id
.krate
);
1353 reexports
.push(Export
{
1362 if let NameBindingKind
::Import { binding: orig_binding, directive, .. }
= binding
.kind
{
1363 if ns
== TypeNS
&& orig_binding
.is_variant() &&
1364 !orig_binding
.vis
.is_at_least(binding
.vis
, &*this
) {
1365 let msg
= match directive
.subclass
{
1366 ImportDirectiveSubclass
::SingleImport { .. }
=> {
1367 format
!("variant `{}` is private and cannot be re-exported",
1370 ImportDirectiveSubclass
::GlobImport { .. }
=> {
1371 let msg
= "enum is private and its variants \
1372 cannot be re-exported".to_owned();
1373 let error_id
= (DiagnosticMessageId
::ErrorId(0), // no code?!
1376 let fresh
= this
.session
.one_time_diagnostics
1377 .borrow_mut().insert(error_id
);
1383 ref s @ _
=> bug
!("unexpected import subclass {:?}", s
)
1385 let mut err
= this
.session
.struct_span_err(binding
.span
, &msg
);
1387 let imported_module
= match directive
.imported_module
.get() {
1388 Some(ModuleOrUniformRoot
::Module(module
)) => module
,
1389 _
=> bug
!("module should exist"),
1391 let parent_module
= imported_module
.parent
.expect("parent should exist");
1392 let resolutions
= this
.resolutions(parent_module
).borrow();
1393 let enum_path_segment_index
= directive
.module_path
.len() - 1;
1394 let enum_ident
= directive
.module_path
[enum_path_segment_index
].ident
;
1396 let key
= this
.new_key(enum_ident
, TypeNS
);
1397 let enum_resolution
= resolutions
.get(&key
)
1398 .expect("resolution should exist");
1399 let enum_span
= enum_resolution
.borrow()
1400 .binding
.expect("binding should exist")
1402 let enum_def_span
= this
.session
.source_map().def_span(enum_span
);
1403 let enum_def_snippet
= this
.session
.source_map()
1404 .span_to_snippet(enum_def_span
).expect("snippet should exist");
1405 // potentially need to strip extant `crate`/`pub(path)` for suggestion
1406 let after_vis_index
= enum_def_snippet
.find("enum")
1407 .expect("`enum` keyword should exist in snippet");
1408 let suggestion
= format
!("pub {}",
1409 &enum_def_snippet
[after_vis_index
..]);
1412 .diag_span_suggestion_once(&mut err
,
1413 DiagnosticMessageId
::ErrorId(0),
1415 "consider making the enum public",
1422 if reexports
.len() > 0 {
1423 if let Some(def_id
) = module
.def_id() {
1424 self.r
.export_map
.insert(def_id
, reexports
);
1430 fn import_path_to_string(names
: &[Ident
],
1431 subclass
: &ImportDirectiveSubclass
<'_
>,
1432 span
: Span
) -> String
{
1433 let pos
= names
.iter()
1434 .position(|p
| span
== p
.span
&& p
.name
!= kw
::PathRoot
);
1435 let global
= !names
.is_empty() && names
[0].name
== kw
::PathRoot
;
1436 if let Some(pos
) = pos
{
1437 let names
= if global { &names[1..pos + 1] }
else { &names[..pos + 1] }
;
1438 names_to_string(&names
.iter().map(|ident
| ident
.name
).collect
::<Vec
<_
>>())
1440 let names
= if global { &names[1..] }
else { names }
;
1441 if names
.is_empty() {
1442 import_directive_subclass_to_string(subclass
)
1446 names_to_string(&names
.iter().map(|ident
| ident
.name
).collect
::<Vec
<_
>>()),
1447 import_directive_subclass_to_string(subclass
),
1453 fn import_directive_subclass_to_string(subclass
: &ImportDirectiveSubclass
<'_
>) -> String
{
1455 SingleImport { source, .. }
=> source
.to_string(),
1456 GlobImport { .. }
=> "*".to_string(),
1457 ExternCrate { .. }
=> "<extern crate>".to_string(),
1458 MacroUse
=> "#[macro_use]".to_string(),