4 use rustc_ast
::{self as ast, Path}
;
5 use rustc_ast_pretty
::pprust
;
6 use rustc_data_structures
::fx
::FxHashSet
;
7 use rustc_errors
::{struct_span_err, Applicability, DiagnosticBuilder}
;
8 use rustc_feature
::BUILTIN_ATTRIBUTES
;
9 use rustc_hir
::def
::Namespace
::{self, *}
;
10 use rustc_hir
::def
::{self, CtorKind, CtorOf, DefKind, NonMacroAttrKind}
;
11 use rustc_hir
::def_id
::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE}
;
12 use rustc_middle
::bug
;
13 use rustc_middle
::ty
::{self, DefIdTree}
;
14 use rustc_session
::Session
;
15 use rustc_span
::hygiene
::MacroKind
;
16 use rustc_span
::lev_distance
::find_best_match_for_name
;
17 use rustc_span
::source_map
::SourceMap
;
18 use rustc_span
::symbol
::{kw, sym, Ident, Symbol}
;
19 use rustc_span
::{BytePos, MultiSpan, Span}
;
22 use crate::imports
::{Import, ImportKind, ImportResolver}
;
23 use crate::path_names_to_string
;
24 use crate::{AmbiguityError, AmbiguityErrorMisc, AmbiguityKind}
;
26 BindingError
, CrateLint
, HasGenericParams
, MacroRulesScope
, Module
, ModuleOrUniformRoot
,
28 use crate::{NameBinding, NameBindingKind, PrivacyError, VisResolutionError}
;
29 use crate::{ParentScope, PathResult, ResolutionError, Resolver, Scope, ScopeSet, Segment}
;
31 type Res
= def
::Res
<ast
::NodeId
>;
33 /// A vector of spans and replacements, a message and applicability.
34 crate type Suggestion
= (Vec
<(Span
, String
)>, String
, Applicability
);
36 /// Potential candidate for an undeclared or out-of-scope label - contains the ident of a
37 /// similarly named label and whether or not it is reachable.
38 crate type LabelSuggestion
= (Ident
, bool
);
40 crate struct TypoSuggestion
{
41 pub candidate
: Symbol
,
46 crate fn from_res(candidate
: Symbol
, res
: Res
) -> TypoSuggestion
{
47 TypoSuggestion { candidate, res }
51 /// A free importable items suggested in case of resolution failure.
52 crate struct ImportSuggestion
{
53 pub did
: Option
<DefId
>,
54 pub descr
: &'
static str,
59 /// Adjust the impl span so that just the `impl` keyword is taken by removing
60 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
61 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`).
63 /// *Attention*: the method used is very fragile since it essentially duplicates the work of the
64 /// parser. If you need to use this function or something similar, please consider updating the
65 /// `source_map` functions and this function to something more robust.
66 fn reduce_impl_span_to_impl_keyword(sm
: &SourceMap
, impl_span
: Span
) -> Span
{
67 let impl_span
= sm
.span_until_char(impl_span
, '
<'
);
68 sm
.span_until_whitespace(impl_span
)
71 impl<'a
> Resolver
<'a
> {
72 crate fn add_module_candidates(
75 names
: &mut Vec
<TypoSuggestion
>,
76 filter_fn
: &impl Fn(Res
) -> bool
,
78 for (key
, resolution
) in self.resolutions(module
).borrow().iter() {
79 if let Some(binding
) = resolution
.borrow().binding
{
80 let res
= binding
.res();
82 names
.push(TypoSuggestion
::from_res(key
.ident
.name
, res
));
88 /// Combines an error with provided span and emits it.
90 /// This takes the error provided, combines it with the span and any additional spans inside the
91 /// error and emits it.
92 crate fn report_error(&self, span
: Span
, resolution_error
: ResolutionError
<'_
>) {
93 self.into_struct_error(span
, resolution_error
).emit();
96 crate fn into_struct_error(
99 resolution_error
: ResolutionError
<'_
>,
100 ) -> DiagnosticBuilder
<'_
> {
101 match resolution_error
{
102 ResolutionError
::GenericParamsFromOuterFunction(outer_res
, has_generic_params
) => {
103 let mut err
= struct_span_err
!(
107 "can't use generic parameters from outer function",
109 err
.span_label(span
, "use of generic parameter from outer function".to_string());
111 let sm
= self.session
.source_map();
113 Res
::SelfTy(maybe_trait_defid
, maybe_impl_defid
) => {
114 if let Some(impl_span
) =
115 maybe_impl_defid
.and_then(|(def_id
, _
)| self.opt_span(def_id
))
118 reduce_impl_span_to_impl_keyword(sm
, impl_span
),
119 "`Self` type implicitly declared here, by this `impl`",
122 match (maybe_trait_defid
, maybe_impl_defid
) {
124 err
.span_label(span
, "can't use `Self` here");
127 err
.span_label(span
, "use a type here instead");
129 (None
, None
) => bug
!("`impl` without trait nor type?"),
133 Res
::Def(DefKind
::TyParam
, def_id
) => {
134 if let Some(span
) = self.opt_span(def_id
) {
135 err
.span_label(span
, "type parameter from outer function");
138 Res
::Def(DefKind
::ConstParam
, def_id
) => {
139 if let Some(span
) = self.opt_span(def_id
) {
140 err
.span_label(span
, "const parameter from outer function");
145 "GenericParamsFromOuterFunction should only be used with Res::SelfTy, \
146 DefKind::TyParam or DefKind::ConstParam"
151 if has_generic_params
== HasGenericParams
::Yes
{
152 // Try to retrieve the span of the function signature and generate a new
153 // message with a local type or const parameter.
154 let sugg_msg
= "try using a local generic parameter instead";
155 if let Some((sugg_span
, snippet
)) = sm
.generate_local_type_param_snippet(span
) {
156 // Suggest the modification to the user
161 Applicability
::MachineApplicable
,
163 } else if let Some(sp
) = sm
.generate_fn_name_span(span
) {
166 "try adding a local generic parameter in this method instead"
170 err
.help("try using a local generic parameter instead");
176 ResolutionError
::NameAlreadyUsedInParameterList(name
, first_use_span
) => {
177 let mut err
= struct_span_err
!(
181 "the name `{}` is already used for a generic \
182 parameter in this item's generic parameters",
185 err
.span_label(span
, "already used");
186 err
.span_label(first_use_span
, format
!("first use of `{}`", name
));
189 ResolutionError
::MethodNotMemberOfTrait(method
, trait_
) => {
190 let mut err
= struct_span_err
!(
194 "method `{}` is not a member of trait `{}`",
198 err
.span_label(span
, format
!("not a member of trait `{}`", trait_
));
201 ResolutionError
::TypeNotMemberOfTrait(type_
, trait_
) => {
202 let mut err
= struct_span_err
!(
206 "type `{}` is not a member of trait `{}`",
210 err
.span_label(span
, format
!("not a member of trait `{}`", trait_
));
213 ResolutionError
::ConstNotMemberOfTrait(const_
, trait_
) => {
214 let mut err
= struct_span_err
!(
218 "const `{}` is not a member of trait `{}`",
222 err
.span_label(span
, format
!("not a member of trait `{}`", trait_
));
225 ResolutionError
::VariableNotBoundInPattern(binding_error
) => {
226 let BindingError { name, target, origin, could_be_path }
= binding_error
;
228 let target_sp
= target
.iter().copied().collect
::<Vec
<_
>>();
229 let origin_sp
= origin
.iter().copied().collect
::<Vec
<_
>>();
231 let msp
= MultiSpan
::from_spans(target_sp
.clone());
232 let mut err
= struct_span_err
!(
236 "variable `{}` is not bound in all patterns",
239 for sp
in target_sp
{
240 err
.span_label(sp
, format
!("pattern doesn't bind `{}`", name
));
242 for sp
in origin_sp
{
243 err
.span_label(sp
, "variable not in all patterns");
246 let help_msg
= format
!(
247 "if you meant to match on a variant or a `const` item, consider \
248 making the path in the pattern qualified: `?::{}`",
251 err
.span_help(span
, &help_msg
);
255 ResolutionError
::VariableBoundWithDifferentMode(variable_name
, first_binding_span
) => {
256 let mut err
= struct_span_err
!(
260 "variable `{}` is bound inconsistently across alternatives separated by `|`",
263 err
.span_label(span
, "bound in different ways");
264 err
.span_label(first_binding_span
, "first binding");
267 ResolutionError
::IdentifierBoundMoreThanOnceInParameterList(identifier
) => {
268 let mut err
= struct_span_err
!(
272 "identifier `{}` is bound more than once in this parameter list",
275 err
.span_label(span
, "used as parameter more than once");
278 ResolutionError
::IdentifierBoundMoreThanOnceInSamePattern(identifier
) => {
279 let mut err
= struct_span_err
!(
283 "identifier `{}` is bound more than once in the same pattern",
286 err
.span_label(span
, "used in a pattern more than once");
289 ResolutionError
::UndeclaredLabel { name, suggestion }
=> {
290 let mut err
= struct_span_err
!(
294 "use of undeclared label `{}`",
298 err
.span_label(span
, format
!("undeclared label `{}`", name
));
301 // A reachable label with a similar name exists.
302 Some((ident
, true)) => {
303 err
.span_label(ident
.span
, "a label with a similar name is reachable");
306 "try using similarly named label",
307 ident
.name
.to_string(),
308 Applicability
::MaybeIncorrect
,
311 // An unreachable label with a similar name exists.
312 Some((ident
, false)) => {
315 "a label with a similar name exists but is unreachable",
318 // No similarly-named labels exist.
324 ResolutionError
::SelfImportsOnlyAllowedWithin { root, span_with_rename }
=> {
325 let mut err
= struct_span_err
!(
330 "`self` imports are only allowed within a { } list"
333 // None of the suggestions below would help with a case like `use self`.
335 // use foo::bar::self -> foo::bar
336 // use foo::bar::self as abc -> foo::bar as abc
339 "consider importing the module directly",
341 Applicability
::MachineApplicable
,
344 // use foo::bar::self -> foo::bar::{self}
345 // use foo::bar::self as abc -> foo::bar::{self as abc}
347 (span_with_rename
.shrink_to_lo(), "{".to_string()),
348 (span_with_rename
.shrink_to_hi(), "}".to_string()),
350 err
.multipart_suggestion(
351 "alternatively, use the multi-path `use` syntax to import `self`",
353 Applicability
::MachineApplicable
,
358 ResolutionError
::SelfImportCanOnlyAppearOnceInTheList
=> {
359 let mut err
= struct_span_err
!(
363 "`self` import can only appear once in an import list"
365 err
.span_label(span
, "can only appear once in an import list");
368 ResolutionError
::SelfImportOnlyInImportListWithNonEmptyPrefix
=> {
369 let mut err
= struct_span_err
!(
373 "`self` import can only appear in an import list with \
376 err
.span_label(span
, "can only appear in an import list with a non-empty prefix");
379 ResolutionError
::FailedToResolve { label, suggestion }
=> {
381 struct_span_err
!(self.session
, span
, E0433
, "failed to resolve: {}", &label
);
382 err
.span_label(span
, label
);
384 if let Some((suggestions
, msg
, applicability
)) = suggestion
{
385 err
.multipart_suggestion(&msg
, suggestions
, applicability
);
390 ResolutionError
::CannotCaptureDynamicEnvironmentInFnItem
=> {
391 let mut err
= struct_span_err
!(
396 "can't capture dynamic environment in a fn item"
398 err
.help("use the `|| { ... }` closure form instead");
401 ResolutionError
::AttemptToUseNonConstantValueInConstant
=> {
402 let mut err
= struct_span_err
!(
406 "attempt to use a non-constant value in a constant"
408 err
.span_label(span
, "non-constant value");
411 ResolutionError
::BindingShadowsSomethingUnacceptable(what_binding
, name
, binding
) => {
412 let res
= binding
.res();
413 let shadows_what
= res
.descr();
414 let mut err
= struct_span_err
!(
418 "{}s cannot shadow {}s",
424 format
!("cannot be named the same as {} {}", res
.article(), shadows_what
),
426 let participle
= if binding
.is_import() { "imported" }
else { "defined" }
;
427 let msg
= format
!("the {} `{}` is {} here", shadows_what
, name
, participle
);
428 err
.span_label(binding
.span
, msg
);
431 ResolutionError
::ForwardDeclaredTyParam
=> {
432 let mut err
= struct_span_err
!(
436 "type parameters with a default cannot use \
437 forward declared identifiers"
441 "defaulted type parameters cannot be forward declared".to_string(),
445 ResolutionError
::ParamInTyOfConstParam(name
) => {
446 let mut err
= struct_span_err
!(
450 "the type of const parameters must not depend on other generic parameters"
454 format
!("the type must not depend on the parameter `{}`", name
),
458 ResolutionError
::ParamInAnonConstInTyDefault(name
) => {
459 let mut err
= self.session
.struct_span_err(
461 "constant values inside of type parameter defaults must not depend on generic parameters",
465 format
!("the anonymous constant must not depend on the parameter `{}`", name
),
469 ResolutionError
::ParamInNonTrivialAnonConst { name, is_type }
=> {
470 let mut err
= self.session
.struct_span_err(
472 "generic parameters may not be used in const operations",
474 err
.span_label(span
, &format
!("cannot perform const operation using `{}`", name
));
477 err
.note("type parameters may not be used in const expressions");
480 "const parameters may only be used as standalone arguments, i.e. `{}`",
484 err
.help("use `#![feature(const_generics)]` and `#![feature(const_evaluatable_checked)]` to allow generic const expressions");
488 ResolutionError
::SelfInTyParamDefault
=> {
489 let mut err
= struct_span_err
!(
493 "type parameters cannot use `Self` in their defaults"
495 err
.span_label(span
, "`Self` in type parameter default".to_string());
498 ResolutionError
::UnreachableLabel { name, definition_span, suggestion }
=> {
499 let mut err
= struct_span_err
!(
503 "use of unreachable label `{}`",
507 err
.span_label(definition_span
, "unreachable label defined here");
508 err
.span_label(span
, format
!("unreachable label `{}`", name
));
510 "labels are unreachable through functions, closures, async blocks and modules",
514 // A reachable label with a similar name exists.
515 Some((ident
, true)) => {
516 err
.span_label(ident
.span
, "a label with a similar name is reachable");
519 "try using similarly named label",
520 ident
.name
.to_string(),
521 Applicability
::MaybeIncorrect
,
524 // An unreachable label with a similar name exists.
525 Some((ident
, false)) => {
528 "a label with a similar name exists but is also unreachable",
531 // No similarly-named labels exist.
540 crate fn report_vis_error(&self, vis_resolution_error
: VisResolutionError
<'_
>) {
541 match vis_resolution_error
{
542 VisResolutionError
::Relative2018(span
, path
) => {
543 let mut err
= self.session
.struct_span_err(
545 "relative paths are not supported in visibilities on 2018 edition",
550 format
!("crate::{}", pprust
::path_to_string(&path
)),
551 Applicability
::MaybeIncorrect
,
555 VisResolutionError
::AncestorOnly(span
) => struct_span_err
!(
559 "visibilities can only be restricted to ancestor modules"
561 VisResolutionError
::FailedToResolve(span
, label
, suggestion
) => {
562 self.into_struct_error(span
, ResolutionError
::FailedToResolve { label, suggestion }
)
564 VisResolutionError
::ExpectedFound(span
, path_str
, res
) => {
565 let mut err
= struct_span_err
!(
569 "expected module, found {} `{}`",
573 err
.span_label(span
, "not a module");
576 VisResolutionError
::Indeterminate(span
) => struct_span_err
!(
580 "cannot determine resolution for the visibility"
582 VisResolutionError
::ModuleOnly(span
) => {
583 self.session
.struct_span_err(span
, "visibility must resolve to a module")
589 /// Lookup typo candidate in scope for a macro or import.
590 fn early_lookup_typo_candidate(
593 parent_scope
: &ParentScope
<'a
>,
595 filter_fn
: &impl Fn(Res
) -> bool
,
596 ) -> Option
<TypoSuggestion
> {
597 let mut suggestions
= Vec
::new();
598 self.visit_scopes(scope_set
, parent_scope
, ident
, |this
, scope
, use_prelude
, _
| {
600 Scope
::DeriveHelpers(expn_id
) => {
601 let res
= Res
::NonMacroAttr(NonMacroAttrKind
::DeriveHelper
);
608 .map(|ident
| TypoSuggestion
::from_res(ident
.name
, res
)),
612 Scope
::DeriveHelpersCompat
=> {
613 let res
= Res
::NonMacroAttr(NonMacroAttrKind
::DeriveHelperCompat
);
615 for derive
in parent_scope
.derives
{
616 let parent_scope
= &ParentScope { derives: &[], ..*parent_scope }
;
617 if let Ok((Some(ext
), _
)) = this
.resolve_macro_path(
619 Some(MacroKind
::Derive
),
627 .map(|name
| TypoSuggestion
::from_res(*name
, res
)),
633 Scope
::MacroRules(macro_rules_scope
) => {
634 if let MacroRulesScope
::Binding(macro_rules_binding
) = macro_rules_scope
.get() {
635 let res
= macro_rules_binding
.binding
.res();
638 .push(TypoSuggestion
::from_res(macro_rules_binding
.ident
.name
, res
))
642 Scope
::CrateRoot
=> {
643 let root_ident
= Ident
::new(kw
::PathRoot
, ident
.span
);
644 let root_module
= this
.resolve_crate_root(root_ident
);
645 this
.add_module_candidates(root_module
, &mut suggestions
, filter_fn
);
647 Scope
::Module(module
) => {
648 this
.add_module_candidates(module
, &mut suggestions
, filter_fn
);
650 Scope
::RegisteredAttrs
=> {
651 let res
= Res
::NonMacroAttr(NonMacroAttrKind
::Registered
);
654 this
.registered_attrs
656 .map(|ident
| TypoSuggestion
::from_res(ident
.name
, res
)),
660 Scope
::MacroUsePrelude
=> {
661 suggestions
.extend(this
.macro_use_prelude
.iter().filter_map(
663 let res
= binding
.res();
664 filter_fn(res
).then_some(TypoSuggestion
::from_res(*name
, res
))
668 Scope
::BuiltinAttrs
=> {
669 let res
= Res
::NonMacroAttr(NonMacroAttrKind
::Builtin
);
674 .map(|(name
, ..)| TypoSuggestion
::from_res(*name
, res
)),
678 Scope
::ExternPrelude
=> {
679 suggestions
.extend(this
.extern_prelude
.iter().filter_map(|(ident
, _
)| {
680 let res
= Res
::Def(DefKind
::Mod
, DefId
::local(CRATE_DEF_INDEX
));
681 filter_fn(res
).then_some(TypoSuggestion
::from_res(ident
.name
, res
))
684 Scope
::ToolPrelude
=> {
685 let res
= Res
::NonMacroAttr(NonMacroAttrKind
::Tool
);
687 this
.registered_tools
689 .map(|ident
| TypoSuggestion
::from_res(ident
.name
, res
)),
692 Scope
::StdLibPrelude
=> {
693 if let Some(prelude
) = this
.prelude
{
694 let mut tmp_suggestions
= Vec
::new();
695 this
.add_module_candidates(prelude
, &mut tmp_suggestions
, filter_fn
);
699 .filter(|s
| use_prelude
|| this
.is_builtin_macro(s
.res
)),
703 Scope
::BuiltinTypes
=> {
704 let primitive_types
= &this
.primitive_type_table
.primitive_types
;
705 suggestions
.extend(primitive_types
.iter().flat_map(|(name
, prim_ty
)| {
706 let res
= Res
::PrimTy(*prim_ty
);
707 filter_fn(res
).then_some(TypoSuggestion
::from_res(*name
, res
))
715 // Make sure error reporting is deterministic.
716 suggestions
.sort_by_cached_key(|suggestion
| suggestion
.candidate
.as_str());
718 match find_best_match_for_name(
719 &suggestions
.iter().map(|suggestion
| suggestion
.candidate
).collect
::<Vec
<Symbol
>>(),
723 Some(found
) if found
!= ident
.name
=> {
724 suggestions
.into_iter().find(|suggestion
| suggestion
.candidate
== found
)
730 fn lookup_import_candidates_from_module
<FilterFn
>(
733 namespace
: Namespace
,
734 parent_scope
: &ParentScope
<'a
>,
735 start_module
: Module
<'a
>,
738 ) -> Vec
<ImportSuggestion
>
740 FilterFn
: Fn(Res
) -> bool
,
742 let mut candidates
= Vec
::new();
743 let mut seen_modules
= FxHashSet
::default();
744 let not_local_module
= crate_name
.name
!= kw
::Crate
;
746 vec
![(start_module
, Vec
::<ast
::PathSegment
>::new(), true, not_local_module
)];
747 let mut worklist_via_import
= vec
![];
749 while let Some((in_module
, path_segments
, accessible
, in_module_is_extern
)) =
750 match worklist
.pop() {
751 None
=> worklist_via_import
.pop(),
755 // We have to visit module children in deterministic order to avoid
756 // instabilities in reported imports (#43552).
757 in_module
.for_each_child(self, |this
, ident
, ns
, name_binding
| {
758 // avoid non-importable candidates
759 if !name_binding
.is_importable() {
763 let child_accessible
=
764 accessible
&& this
.is_accessible_from(name_binding
.vis
, parent_scope
.module
);
766 // do not venture inside inaccessible items of other crates
767 if in_module_is_extern
&& !child_accessible
{
771 let via_import
= name_binding
.is_import() && !name_binding
.is_extern_crate();
773 // There is an assumption elsewhere that paths of variants are in the enum's
774 // declaration and not imported. With this assumption, the variant component is
775 // chopped and the rest of the path is assumed to be the enum's own path. For
776 // errors where a variant is used as the type instead of the enum, this causes
777 // funny looking invalid suggestions, i.e `foo` instead of `foo::MyEnum`.
778 if via_import
&& name_binding
.is_possibly_imported_variant() {
782 // collect results based on the filter function
783 // avoid suggesting anything from the same module in which we are resolving
784 if ident
.name
== lookup_ident
.name
786 && !ptr
::eq(in_module
, parent_scope
.module
)
788 let res
= name_binding
.res();
791 let mut segms
= path_segments
.clone();
792 if lookup_ident
.span
.rust_2018() {
793 // crate-local absolute paths start with `crate::` in edition 2018
794 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
795 segms
.insert(0, ast
::PathSegment
::from_ident(crate_name
));
798 segms
.push(ast
::PathSegment
::from_ident(ident
));
799 let path
= Path { span: name_binding.span, segments: segms, tokens: None }
;
800 let did
= match res
{
801 Res
::Def(DefKind
::Ctor(..), did
) => this
.parent(did
),
802 _
=> res
.opt_def_id(),
805 if child_accessible
{
806 // Remove invisible match if exists
807 if let Some(idx
) = candidates
809 .position(|v
: &ImportSuggestion
| v
.did
== did
&& !v
.accessible
)
811 candidates
.remove(idx
);
815 if candidates
.iter().all(|v
: &ImportSuggestion
| v
.did
!= did
) {
816 candidates
.push(ImportSuggestion
{
820 accessible
: child_accessible
,
826 // collect submodules to explore
827 if let Some(module
) = name_binding
.module() {
829 let mut path_segments
= path_segments
.clone();
830 path_segments
.push(ast
::PathSegment
::from_ident(ident
));
832 let is_extern_crate_that_also_appears_in_prelude
=
833 name_binding
.is_extern_crate() && lookup_ident
.span
.rust_2018();
835 if !is_extern_crate_that_also_appears_in_prelude
{
836 let is_extern
= in_module_is_extern
|| name_binding
.is_extern_crate();
837 // add the module to the lookup
838 if seen_modules
.insert(module
.def_id().unwrap()) {
839 if via_import { &mut worklist_via_import }
else { &mut worklist }
840 .push((module
, path_segments
, child_accessible
, is_extern
));
847 // If only some candidates are accessible, take just them
848 if !candidates
.iter().all(|v
: &ImportSuggestion
| !v
.accessible
) {
849 candidates
= candidates
.into_iter().filter(|x
| x
.accessible
).collect();
855 /// When name resolution fails, this method can be used to look up candidate
856 /// entities with the expected name. It allows filtering them using the
857 /// supplied predicate (which should be used to only accept the types of
858 /// definitions expected, e.g., traits). The lookup spans across all crates.
860 /// N.B., the method does not look into imports, but this is not a problem,
861 /// since we report the definitions (thus, the de-aliased imports).
862 crate fn lookup_import_candidates
<FilterFn
>(
865 namespace
: Namespace
,
866 parent_scope
: &ParentScope
<'a
>,
868 ) -> Vec
<ImportSuggestion
>
870 FilterFn
: Fn(Res
) -> bool
,
872 let mut suggestions
= self.lookup_import_candidates_from_module(
877 Ident
::with_dummy_span(kw
::Crate
),
881 if lookup_ident
.span
.rust_2018() {
882 let extern_prelude_names
= self.extern_prelude
.clone();
883 for (ident
, _
) in extern_prelude_names
.into_iter() {
884 if ident
.span
.from_expansion() {
885 // Idents are adjusted to the root context before being
886 // resolved in the extern prelude, so reporting this to the
887 // user is no help. This skips the injected
888 // `extern crate std` in the 2018 edition, which would
889 // otherwise cause duplicate suggestions.
892 if let Some(crate_id
) = self.crate_loader
.maybe_process_path_extern(ident
.name
) {
894 self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX }
);
895 suggestions
.extend(self.lookup_import_candidates_from_module(
910 crate fn unresolved_macro_suggestions(
912 err
: &mut DiagnosticBuilder
<'a
>,
913 macro_kind
: MacroKind
,
914 parent_scope
: &ParentScope
<'a
>,
917 let is_expected
= &|res
: Res
| res
.macro_kind() == Some(macro_kind
);
918 let suggestion
= self.early_lookup_typo_candidate(
919 ScopeSet
::Macro(macro_kind
),
924 self.add_typo_suggestion(err
, suggestion
, ident
.span
);
926 let import_suggestions
=
927 self.lookup_import_candidates(ident
, Namespace
::MacroNS
, parent_scope
, |res
| {
928 matches
!(res
, Res
::Def(DefKind
::Macro(MacroKind
::Bang
), _
))
930 show_candidates(err
, None
, &import_suggestions
, false, true);
932 if macro_kind
== MacroKind
::Derive
&& (ident
.name
== sym
::Send
|| ident
.name
== sym
::Sync
) {
933 let msg
= format
!("unsafe traits like `{}` should be implemented explicitly", ident
);
934 err
.span_note(ident
.span
, &msg
);
936 if self.macro_names
.contains(&ident
.normalize_to_macros_2_0()) {
937 err
.help("have you added the `#[macro_use]` on the module/import?");
941 crate fn add_typo_suggestion(
943 err
: &mut DiagnosticBuilder
<'_
>,
944 suggestion
: Option
<TypoSuggestion
>,
947 let suggestion
= match suggestion
{
948 None
=> return false,
949 // We shouldn't suggest underscore.
950 Some(suggestion
) if suggestion
.candidate
== kw
::Underscore
=> return false,
951 Some(suggestion
) => suggestion
,
953 let def_span
= suggestion
.res
.opt_def_id().and_then(|def_id
| match def_id
.krate
{
954 LOCAL_CRATE
=> self.opt_span(def_id
),
958 .guess_head_span(self.cstore().get_span_untracked(def_id
, self.session
)),
961 if let Some(def_span
) = def_span
{
962 if span
.overlaps(def_span
) {
963 // Don't suggest typo suggestion for itself like in the followoing:
964 // error[E0423]: expected function, tuple struct or tuple variant, found struct `X`
965 // --> $DIR/issue-64792-bad-unicode-ctor.rs:3:14
968 // | ----------- `X` defined here
970 // LL | const Y: X = X("ö");
971 // | -------------^^^^^^- similarly named constant `Y` defined here
973 // help: use struct literal syntax instead
975 // LL | const Y: X = X {};
977 // help: a constant with a similar name exists
979 // LL | const Y: X = Y("ö");
984 self.session
.source_map().guess_head_span(def_span
),
986 "similarly named {} `{}` defined here",
987 suggestion
.res
.descr(),
988 suggestion
.candidate
.as_str(),
993 "{} {} with a similar name exists",
994 suggestion
.res
.article(),
995 suggestion
.res
.descr()
1000 suggestion
.candidate
.to_string(),
1001 Applicability
::MaybeIncorrect
,
1006 fn binding_description(&self, b
: &NameBinding
<'_
>, ident
: Ident
, from_prelude
: bool
) -> String
{
1008 if b
.span
.is_dummy() {
1009 // These already contain the "built-in" prefix or look bad with it.
1011 !matches
!(b
.res(), Res
::NonMacroAttr(..) | Res
::PrimTy(..) | Res
::ToolMod
);
1012 let (built_in
, from
) = if from_prelude
{
1013 ("", " from prelude")
1014 } else if b
.is_extern_crate()
1016 && self.session
.opts
.externs
.get(&ident
.as_str()).is_some()
1018 ("", " passed with `--extern`")
1019 } else if add_built_in
{
1025 let a
= if built_in
.is_empty() { res.article() }
else { "a" }
;
1026 format
!("{a}{built_in} {thing}{from}", thing
= res
.descr())
1028 let introduced
= if b
.is_import() { "imported" }
else { "defined" }
;
1029 format
!("the {thing} {introduced} here", thing
= res
.descr())
1033 crate fn report_ambiguity_error(&self, ambiguity_error
: &AmbiguityError
<'_
>) {
1034 let AmbiguityError { kind, ident, b1, b2, misc1, misc2 }
= *ambiguity_error
;
1035 let (b1
, b2
, misc1
, misc2
, swapped
) = if b2
.span
.is_dummy() && !b1
.span
.is_dummy() {
1036 // We have to print the span-less alternative first, otherwise formatting looks bad.
1037 (b2
, b1
, misc2
, misc1
, true)
1039 (b1
, b2
, misc1
, misc2
, false)
1042 let mut err
= struct_span_err
!(
1046 "`{ident}` is ambiguous ({why})",
1049 err
.span_label(ident
.span
, "ambiguous name");
1051 let mut could_refer_to
= |b
: &NameBinding
<'_
>, misc
: AmbiguityErrorMisc
, also
: &str| {
1052 let what
= self.binding_description(b
, ident
, misc
== AmbiguityErrorMisc
::FromPrelude
);
1053 let note_msg
= format
!("`{ident}` could{also} refer to {what}");
1055 let thing
= b
.res().descr();
1056 let mut help_msgs
= Vec
::new();
1057 if b
.is_glob_import()
1058 && (kind
== AmbiguityKind
::GlobVsGlob
1059 || kind
== AmbiguityKind
::GlobVsExpanded
1060 || kind
== AmbiguityKind
::GlobVsOuter
&& swapped
!= also
.is_empty())
1062 help_msgs
.push(format
!(
1063 "consider adding an explicit import of `{ident}` to disambiguate"
1066 if b
.is_extern_crate() && ident
.span
.rust_2018() {
1067 help_msgs
.push(format
!("use `::{ident}` to refer to this {thing} unambiguously"))
1069 if misc
== AmbiguityErrorMisc
::SuggestCrate
{
1071 .push(format
!("use `crate::{ident}` to refer to this {thing} unambiguously"))
1072 } else if misc
== AmbiguityErrorMisc
::SuggestSelf
{
1074 .push(format
!("use `self::{ident}` to refer to this {thing} unambiguously"))
1077 err
.span_note(b
.span
, ¬e_msg
);
1078 for (i
, help_msg
) in help_msgs
.iter().enumerate() {
1079 let or
= if i
== 0 { "" }
else { "or " }
;
1080 err
.help(&format
!("{}{}", or
, help_msg
));
1084 could_refer_to(b1
, misc1
, "");
1085 could_refer_to(b2
, misc2
, " also");
1089 /// If the binding refers to a tuple struct constructor with fields,
1090 /// returns the span of its fields.
1091 fn ctor_fields_span(&self, binding
: &NameBinding
<'_
>) -> Option
<Span
> {
1092 if let NameBindingKind
::Res(
1093 Res
::Def(DefKind
::Ctor(CtorOf
::Struct
, CtorKind
::Fn
), ctor_def_id
),
1097 let def_id
= (&*self).parent(ctor_def_id
).expect("no parent for a constructor");
1098 let fields
= self.field_names
.get(&def_id
)?
;
1099 let first_field
= fields
.first()?
; // Handle `struct Foo()`
1100 return Some(fields
.iter().fold(first_field
.span
, |acc
, field
| acc
.to(field
.span
)));
1105 crate fn report_privacy_error(&self, privacy_error
: &PrivacyError
<'_
>) {
1106 let PrivacyError { ident, binding, .. }
= *privacy_error
;
1108 let res
= binding
.res();
1109 let ctor_fields_span
= self.ctor_fields_span(binding
);
1110 let plain_descr
= res
.descr().to_string();
1111 let nonimport_descr
=
1112 if ctor_fields_span
.is_some() { plain_descr + " constructor" }
else { plain_descr }
;
1113 let import_descr
= nonimport_descr
.clone() + " import";
1115 |b
: &NameBinding
<'_
>| if b
.is_import() { &import_descr }
else { &nonimport_descr }
;
1117 // Print the primary message.
1118 let descr
= get_descr(binding
);
1120 struct_span_err
!(self.session
, ident
.span
, E0603
, "{} `{}` is private", descr
, ident
);
1121 err
.span_label(ident
.span
, &format
!("private {}", descr
));
1122 if let Some(span
) = ctor_fields_span
{
1123 err
.span_label(span
, "a constructor is private if any of the fields is private");
1126 // Print the whole import chain to make it easier to see what happens.
1127 let first_binding
= binding
;
1128 let mut next_binding
= Some(binding
);
1129 let mut next_ident
= ident
;
1130 while let Some(binding
) = next_binding
{
1131 let name
= next_ident
;
1132 next_binding
= match binding
.kind
{
1133 _
if res
== Res
::Err
=> None
,
1134 NameBindingKind
::Import { binding, import, .. }
=> match import
.kind
{
1135 _
if binding
.span
.is_dummy() => None
,
1136 ImportKind
::Single { source, .. }
=> {
1137 next_ident
= source
;
1140 ImportKind
::Glob { .. }
| ImportKind
::MacroUse
=> Some(binding
),
1141 ImportKind
::ExternCrate { .. }
=> None
,
1146 let first
= ptr
::eq(binding
, first_binding
);
1148 "{and_refers_to}the {item} `{name}`{which} is defined here{dots}",
1149 and_refers_to
= if first { "" }
else { "...and refers to " }
,
1150 item
= get_descr(binding
),
1151 which
= if first { "" }
else { " which" }
,
1152 dots
= if next_binding
.is_some() { "..." }
else { "" }
,
1154 let def_span
= self.session
.source_map().guess_head_span(binding
.span
);
1155 let mut note_span
= MultiSpan
::from_span(def_span
);
1156 if !first
&& binding
.vis
== ty
::Visibility
::Public
{
1157 note_span
.push_span_label(def_span
, "consider importing it directly".into());
1159 err
.span_note(note_span
, &msg
);
1166 impl<'a
, 'b
> ImportResolver
<'a
, 'b
> {
1167 /// Adds suggestions for a path that cannot be resolved.
1168 pub(crate) fn make_path_suggestion(
1171 mut path
: Vec
<Segment
>,
1172 parent_scope
: &ParentScope
<'b
>,
1173 ) -> Option
<(Vec
<Segment
>, Vec
<String
>)> {
1174 debug
!("make_path_suggestion: span={:?} path={:?}", span
, path
);
1176 match (path
.get(0), path
.get(1)) {
1177 // `{{root}}::ident::...` on both editions.
1178 // On 2015 `{{root}}` is usually added implicitly.
1179 (Some(fst
), Some(snd
))
1180 if fst
.ident
.name
== kw
::PathRoot
&& !snd
.ident
.is_path_segment_keyword() => {}
1181 // `ident::...` on 2018.
1183 if fst
.ident
.span
.rust_2018() && !fst
.ident
.is_path_segment_keyword() =>
1185 // Insert a placeholder that's later replaced by `self`/`super`/etc.
1186 path
.insert(0, Segment
::from_ident(Ident
::invalid()));
1191 self.make_missing_self_suggestion(span
, path
.clone(), parent_scope
)
1192 .or_else(|| self.make_missing_crate_suggestion(span
, path
.clone(), parent_scope
))
1193 .or_else(|| self.make_missing_super_suggestion(span
, path
.clone(), parent_scope
))
1194 .or_else(|| self.make_external_crate_suggestion(span
, path
, parent_scope
))
1197 /// Suggest a missing `self::` if that resolves to an correct module.
1201 /// LL | use foo::Bar;
1202 /// | ^^^ did you mean `self::foo`?
1204 fn make_missing_self_suggestion(
1207 mut path
: Vec
<Segment
>,
1208 parent_scope
: &ParentScope
<'b
>,
1209 ) -> Option
<(Vec
<Segment
>, Vec
<String
>)> {
1210 // Replace first ident with `self` and check if that is valid.
1211 path
[0].ident
.name
= kw
::SelfLower
;
1212 let result
= self.r
.resolve_path(&path
, None
, parent_scope
, false, span
, CrateLint
::No
);
1213 debug
!("make_missing_self_suggestion: path={:?} result={:?}", path
, result
);
1214 if let PathResult
::Module(..) = result { Some((path, Vec::new())) }
else { None }
1217 /// Suggests a missing `crate::` if that resolves to an correct module.
1221 /// LL | use foo::Bar;
1222 /// | ^^^ did you mean `crate::foo`?
1224 fn make_missing_crate_suggestion(
1227 mut path
: Vec
<Segment
>,
1228 parent_scope
: &ParentScope
<'b
>,
1229 ) -> Option
<(Vec
<Segment
>, Vec
<String
>)> {
1230 // Replace first ident with `crate` and check if that is valid.
1231 path
[0].ident
.name
= kw
::Crate
;
1232 let result
= self.r
.resolve_path(&path
, None
, parent_scope
, false, span
, CrateLint
::No
);
1233 debug
!("make_missing_crate_suggestion: path={:?} result={:?}", path
, result
);
1234 if let PathResult
::Module(..) = result
{
1238 "`use` statements changed in Rust 2018; read more at \
1239 <https://doc.rust-lang.org/edition-guide/rust-2018/module-system/path-\
1249 /// Suggests a missing `super::` if that resolves to an correct module.
1253 /// LL | use foo::Bar;
1254 /// | ^^^ did you mean `super::foo`?
1256 fn make_missing_super_suggestion(
1259 mut path
: Vec
<Segment
>,
1260 parent_scope
: &ParentScope
<'b
>,
1261 ) -> Option
<(Vec
<Segment
>, Vec
<String
>)> {
1262 // Replace first ident with `crate` and check if that is valid.
1263 path
[0].ident
.name
= kw
::Super
;
1264 let result
= self.r
.resolve_path(&path
, None
, parent_scope
, false, span
, CrateLint
::No
);
1265 debug
!("make_missing_super_suggestion: path={:?} result={:?}", path
, result
);
1266 if let PathResult
::Module(..) = result { Some((path, Vec::new())) }
else { None }
1269 /// Suggests a missing external crate name if that resolves to an correct module.
1273 /// LL | use foobar::Baz;
1274 /// | ^^^^^^ did you mean `baz::foobar`?
1277 /// Used when importing a submodule of an external crate but missing that crate's
1278 /// name as the first part of path.
1279 fn make_external_crate_suggestion(
1282 mut path
: Vec
<Segment
>,
1283 parent_scope
: &ParentScope
<'b
>,
1284 ) -> Option
<(Vec
<Segment
>, Vec
<String
>)> {
1285 if path
[1].ident
.span
.rust_2015() {
1289 // Sort extern crate names in reverse order to get
1290 // 1) some consistent ordering for emitted diagnostics, and
1291 // 2) `std` suggestions before `core` suggestions.
1292 let mut extern_crate_names
=
1293 self.r
.extern_prelude
.iter().map(|(ident
, _
)| ident
.name
).collect
::<Vec
<_
>>();
1294 extern_crate_names
.sort_by_key(|name
| Reverse(name
.as_str()));
1296 for name
in extern_crate_names
.into_iter() {
1297 // Replace first ident with a crate name and check if that is valid.
1298 path
[0].ident
.name
= name
;
1299 let result
= self.r
.resolve_path(&path
, None
, parent_scope
, false, span
, CrateLint
::No
);
1301 "make_external_crate_suggestion: name={:?} path={:?} result={:?}",
1304 if let PathResult
::Module(..) = result
{
1305 return Some((path
, Vec
::new()));
1312 /// Suggests importing a macro from the root of the crate rather than a module within
1316 /// help: a macro with this name exists at the root of the crate
1318 /// LL | use issue_59764::makro;
1319 /// | ^^^^^^^^^^^^^^^^^^
1321 /// = note: this could be because a macro annotated with `#[macro_export]` will be exported
1322 /// at the root of the crate instead of the module where it is defined
1324 pub(crate) fn check_for_module_export_macro(
1326 import
: &'b Import
<'b
>,
1327 module
: ModuleOrUniformRoot
<'b
>,
1329 ) -> Option
<(Option
<Suggestion
>, Vec
<String
>)> {
1330 let mut crate_module
= if let ModuleOrUniformRoot
::Module(module
) = module
{
1336 while let Some(parent
) = crate_module
.parent
{
1337 crate_module
= parent
;
1340 if ModuleOrUniformRoot
::same_def(ModuleOrUniformRoot
::Module(crate_module
), module
) {
1341 // Don't make a suggestion if the import was already from the root of the
1346 let resolutions
= self.r
.resolutions(crate_module
).borrow();
1347 let resolution
= resolutions
.get(&self.r
.new_key(ident
, MacroNS
))?
;
1348 let binding
= resolution
.borrow().binding()?
;
1349 if let Res
::Def(DefKind
::Macro(MacroKind
::Bang
), _
) = binding
.res() {
1350 let module_name
= crate_module
.kind
.name().unwrap();
1351 let import_snippet
= match import
.kind
{
1352 ImportKind
::Single { source, target, .. }
if source
!= target
=> {
1353 format
!("{} as {}", source
, target
)
1355 _
=> format
!("{}", ident
),
1358 let mut corrections
: Vec
<(Span
, String
)> = Vec
::new();
1359 if !import
.is_nested() {
1360 // Assume this is the easy case of `use issue_59764::foo::makro;` and just remove
1361 // intermediate segments.
1362 corrections
.push((import
.span
, format
!("{}::{}", module_name
, import_snippet
)));
1364 // Find the binding span (and any trailing commas and spaces).
1365 // ie. `use a::b::{c, d, e};`
1367 let (found_closing_brace
, binding_span
) = find_span_of_binding_until_next_binding(
1373 "check_for_module_export_macro: found_closing_brace={:?} binding_span={:?}",
1374 found_closing_brace
, binding_span
1377 let mut removal_span
= binding_span
;
1378 if found_closing_brace
{
1379 // If the binding span ended with a closing brace, as in the below example:
1380 // ie. `use a::b::{c, d};`
1382 // Then expand the span of characters to remove to include the previous
1383 // binding's trailing comma.
1384 // ie. `use a::b::{c, d};`
1386 if let Some(previous_span
) =
1387 extend_span_to_previous_binding(self.r
.session
, binding_span
)
1389 debug
!("check_for_module_export_macro: previous_span={:?}", previous_span
);
1390 removal_span
= removal_span
.with_lo(previous_span
.lo());
1393 debug
!("check_for_module_export_macro: removal_span={:?}", removal_span
);
1395 // Remove the `removal_span`.
1396 corrections
.push((removal_span
, "".to_string()));
1398 // Find the span after the crate name and if it has nested imports immediatately
1399 // after the crate name already.
1400 // ie. `use a::b::{c, d};`
1402 // or `use a::{b, c, d}};`
1404 let (has_nested
, after_crate_name
) = find_span_immediately_after_crate_name(
1410 "check_for_module_export_macro: has_nested={:?} after_crate_name={:?}",
1411 has_nested
, after_crate_name
1414 let source_map
= self.r
.session
.source_map();
1416 // Add the import to the start, with a `{` if required.
1417 let start_point
= source_map
.start_point(after_crate_name
);
1418 if let Ok(start_snippet
) = source_map
.span_to_snippet(start_point
) {
1422 // In this case, `start_snippet` must equal '{'.
1423 format
!("{}{}, ", start_snippet
, import_snippet
)
1425 // In this case, add a `{`, then the moved import, then whatever
1426 // was there before.
1427 format
!("{{{}, {}", import_snippet
, start_snippet
)
1432 // Add a `};` to the end if nested, matching the `{` added at the start.
1434 corrections
.push((source_map
.end_point(after_crate_name
), "};".to_string()));
1438 let suggestion
= Some((
1440 String
::from("a macro with this name exists at the root of the crate"),
1441 Applicability
::MaybeIncorrect
,
1444 "this could be because a macro annotated with `#[macro_export]` will be exported \
1445 at the root of the crate instead of the module where it is defined"
1448 Some((suggestion
, note
))
1455 /// Given a `binding_span` of a binding within a use statement:
1458 /// use foo::{a, b, c};
1462 /// then return the span until the next binding or the end of the statement:
1465 /// use foo::{a, b, c};
1468 pub(crate) fn find_span_of_binding_until_next_binding(
1473 let source_map
= sess
.source_map();
1475 // Find the span of everything after the binding.
1476 // ie. `a, e};` or `a};`
1477 let binding_until_end
= binding_span
.with_hi(use_span
.hi());
1479 // Find everything after the binding but not including the binding.
1480 // ie. `, e};` or `};`
1481 let after_binding_until_end
= binding_until_end
.with_lo(binding_span
.hi());
1483 // Keep characters in the span until we encounter something that isn't a comma or
1487 // Also note whether a closing brace character was encountered. If there
1488 // was, then later go backwards to remove any trailing commas that are left.
1489 let mut found_closing_brace
= false;
1490 let after_binding_until_next_binding
=
1491 source_map
.span_take_while(after_binding_until_end
, |&ch
| {
1493 found_closing_brace
= true;
1495 ch
== ' '
|| ch
== '
,'
1498 // Combine the two spans.
1499 // ie. `a, ` or `a`.
1501 // Removing these would leave `issue_52891::{d, e};` or `issue_52891::{d, e, };`
1502 let span
= binding_span
.with_hi(after_binding_until_next_binding
.hi());
1504 (found_closing_brace
, span
)
1507 /// Given a `binding_span`, return the span through to the comma or opening brace of the previous
1511 /// use foo::a::{a, b, c};
1512 /// ^^--- binding span
1516 /// use foo::{a, b, c};
1517 /// --- binding span
1519 pub(crate) fn extend_span_to_previous_binding(sess
: &Session
, binding_span
: Span
) -> Option
<Span
> {
1520 let source_map
= sess
.source_map();
1522 // `prev_source` will contain all of the source that came before the span.
1523 // Then split based on a command and take the first (ie. closest to our span)
1524 // snippet. In the example, this is a space.
1525 let prev_source
= source_map
.span_to_prev_source(binding_span
).ok()?
;
1527 let prev_comma
= prev_source
.rsplit('
,'
).collect
::<Vec
<_
>>();
1528 let prev_starting_brace
= prev_source
.rsplit('
{'
).collect
::<Vec
<_
>>();
1529 if prev_comma
.len() <= 1 || prev_starting_brace
.len() <= 1 {
1533 let prev_comma
= prev_comma
.first().unwrap();
1534 let prev_starting_brace
= prev_starting_brace
.first().unwrap();
1536 // If the amount of source code before the comma is greater than
1537 // the amount of source code before the starting brace then we've only
1538 // got one item in the nested item (eg. `issue_52891::{self}`).
1539 if prev_comma
.len() > prev_starting_brace
.len() {
1543 Some(binding_span
.with_lo(BytePos(
1544 // Take away the number of bytes for the characters we've found and an
1545 // extra for the comma.
1546 binding_span
.lo().0 - (prev_comma
.as_bytes().len() as u32) - 1,
1550 /// Given a `use_span` of a binding within a use statement, returns the highlighted span and if
1551 /// it is a nested use tree.
1554 /// use foo::a::{b, c};
1555 /// ^^^^^^^^^^ // false
1557 /// use foo::{a, b, c};
1558 /// ^^^^^^^^^^ // true
1560 /// use foo::{a, b::{c, d}};
1561 /// ^^^^^^^^^^^^^^^ // true
1563 fn find_span_immediately_after_crate_name(
1565 module_name
: Symbol
,
1569 "find_span_immediately_after_crate_name: module_name={:?} use_span={:?}",
1570 module_name
, use_span
1572 let source_map
= sess
.source_map();
1574 // Using `use issue_59764::foo::{baz, makro};` as an example throughout..
1575 let mut num_colons
= 0;
1576 // Find second colon.. `use issue_59764:`
1577 let until_second_colon
= source_map
.span_take_while(use_span
, |c
| {
1581 !matches
!(c
, '
:'
if num_colons
== 2)
1583 // Find everything after the second colon.. `foo::{baz, makro};`
1584 let from_second_colon
= use_span
.with_lo(until_second_colon
.hi() + BytePos(1));
1586 let mut found_a_non_whitespace_character
= false;
1587 // Find the first non-whitespace character in `from_second_colon`.. `f`
1588 let after_second_colon
= source_map
.span_take_while(from_second_colon
, |c
| {
1589 if found_a_non_whitespace_character
{
1592 if !c
.is_whitespace() {
1593 found_a_non_whitespace_character
= true;
1598 // Find the first `{` in from_second_colon.. `foo::{`
1599 let next_left_bracket
= source_map
.span_through_char(from_second_colon
, '
{'
);
1601 (next_left_bracket
== after_second_colon
, from_second_colon
)
1604 /// When an entity with a given name is not available in scope, we search for
1605 /// entities with that name in all crates. This method allows outputting the
1606 /// results of this search in a programmer-friendly way
1607 crate fn show_candidates(
1608 err
: &mut DiagnosticBuilder
<'_
>,
1609 // This is `None` if all placement locations are inside expansions
1610 use_placement_span
: Option
<Span
>,
1611 candidates
: &[ImportSuggestion
],
1615 if candidates
.is_empty() {
1619 // we want consistent results across executions, but candidates are produced
1620 // by iterating through a hash map, so make sure they are ordered:
1621 let mut path_strings
: Vec
<_
> =
1622 candidates
.iter().map(|c
| path_names_to_string(&c
.path
)).collect();
1624 path_strings
.sort();
1625 path_strings
.dedup();
1627 let (determiner
, kind
) = if candidates
.len() == 1 {
1628 ("this", candidates
[0].descr
)
1630 ("one of these", "items")
1633 let instead
= if instead { " instead" }
else { "" }
;
1634 let mut msg
= format
!("consider importing {} {}{}", determiner
, kind
, instead
);
1636 if let Some(span
) = use_placement_span
{
1637 for candidate
in &mut path_strings
{
1638 // produce an additional newline to separate the new use statement
1639 // from the directly following item.
1640 let additional_newline
= if found_use { "" }
else { "\n" }
;
1641 *candidate
= format
!("use {};\n{}", candidate
, additional_newline
);
1644 err
.span_suggestions(span
, &msg
, path_strings
.into_iter(), Applicability
::Unspecified
);
1648 for candidate
in path_strings
{
1650 msg
.push_str(&candidate
);