1 //! This module implements [RFC 1946]: Intra-rustdoc-links
3 //! [RFC 1946]: https://github.com/rust-lang/rfcs/blob/master/text/1946-intra-rustdoc-links.md
6 use rustc_data_structures::{fx::FxHashMap, stable_set::FxHashSet};
7 use rustc_errors::{Applicability, DiagnosticBuilder};
8 use rustc_expand::base::SyntaxExtensionKind;
15 use rustc_hir::def_id::{CrateNum, DefId};
16 use rustc_middle::ty::TyCtxt;
17 use rustc_middle::{bug, span_bug, ty};
18 use rustc_resolve::ParentScope;
19 use rustc_session::lint::Lint;
20 use rustc_span::hygiene::{MacroKind, SyntaxContext};
21 use rustc_span::symbol::{sym, Ident, Symbol};
22 use rustc_span::{BytePos, DUMMY_SP};
23 use smallvec::{smallvec, SmallVec};
25 use pulldown_cmark::LinkType;
29 use std::convert::{TryFrom, TryInto};
33 use crate::clean::{self, utils::find_nearest_parent_module, Crate, Item, ItemLink, PrimitiveType};
34 use crate::core::DocContext;
35 use crate::html::markdown::{markdown_links, MarkdownLink};
36 use crate::lint::{BROKEN_INTRA_DOC_LINKS, PRIVATE_INTRA_DOC_LINKS};
37 use crate::passes::Pass;
38 use crate::visit::DocVisitor;
41 crate use early::load_intra_link_crates;
43 crate const COLLECT_INTRA_DOC_LINKS: Pass = Pass {
44 name: "collect-intra-doc-links",
45 run: collect_intra_doc_links,
46 description: "resolves intra-doc links",
49 fn collect_intra_doc_links(krate: Crate, cx: &mut DocContext<'_>) -> Crate {
50 let mut collector = LinkCollector {
53 kind_side_channel: Cell::new(None),
54 visited_links: FxHashMap::default(),
56 collector.visit_crate(&krate);
60 /// Top-level errors emitted by this pass.
62 Resolve(Box<ResolutionFailure<'a>>),
63 AnchorFailure(AnchorFailure),
66 impl<'a> From<ResolutionFailure<'a>> for ErrorKind<'a> {
67 fn from(err: ResolutionFailure<'a>) -> Self {
68 ErrorKind::Resolve(box err)
72 #[derive(Copy, Clone, Debug, Hash)]
75 Primitive(PrimitiveType),
78 type ResolveRes = rustc_hir::def::Res<rustc_ast::NodeId>;
81 fn descr(self) -> &'static str {
83 Res::Def(kind, id) => ResolveRes::Def(kind, id).descr(),
84 Res::Primitive(_) => "builtin type",
88 fn article(self) -> &'static str {
90 Res::Def(kind, id) => ResolveRes::Def(kind, id).article(),
91 Res::Primitive(_) => "a",
95 fn name(self, tcx: TyCtxt<'_>) -> Symbol {
97 Res::Def(_, id) => tcx.item_name(id),
98 Res::Primitive(prim) => prim.as_sym(),
102 fn def_id(self, tcx: TyCtxt<'_>) -> DefId {
104 Res::Def(_, id) => id,
105 Res::Primitive(prim) => *PrimitiveType::primitive_locations(tcx).get(&prim).unwrap(),
109 fn as_hir_res(self) -> Option<rustc_hir::def::Res> {
111 Res::Def(kind, id) => Some(rustc_hir::def::Res::Def(kind, id)),
112 // FIXME: maybe this should handle the subset of PrimitiveType that fits into hir::PrimTy?
113 Res::Primitive(_) => None,
118 impl TryFrom<ResolveRes> for Res {
121 fn try_from(res: ResolveRes) -> Result<Self, ()> {
122 use rustc_hir::def::Res::*;
124 Def(kind, id) => Ok(Res::Def(kind, id)),
125 PrimTy(prim) => Ok(Res::Primitive(PrimitiveType::from_hir(prim))),
127 NonMacroAttr(..) | Err => Result::Err(()),
128 other => bug!("unrecognized res {:?}", other),
133 /// A link failed to resolve.
135 enum ResolutionFailure<'a> {
136 /// This resolved, but with the wrong namespace.
138 /// What the link resolved to.
140 /// The expected namespace for the resolution, determined from the link's disambiguator.
142 /// E.g., for `[fn@Result]` this is [`Namespace::ValueNS`],
143 /// even though `Result`'s actual namespace is [`Namespace::TypeNS`].
144 expected_ns: Namespace,
146 /// The link failed to resolve. [`resolution_failure`] should look to see if there's
147 /// a more helpful error that can be given.
149 /// The scope the link was resolved in.
151 /// If part of the link resolved, this has the `Res`.
153 /// In `[std::io::Error::x]`, `std::io::Error` would be a partial resolution.
154 partial_res: Option<Res>,
155 /// The remaining unresolved path segments.
157 /// In `[std::io::Error::x]`, `x` would be unresolved.
158 unresolved: Cow<'a, str>,
160 /// This happens when rustdoc can't determine the parent scope for an item.
161 /// It is always a bug in rustdoc.
163 /// This link has malformed generic parameters; e.g., the angle brackets are unbalanced.
164 MalformedGenerics(MalformedGenerics),
165 /// Used to communicate that this should be ignored, but shouldn't be reported to the user.
167 /// This happens when there is no disambiguator and one of the namespaces
168 /// failed to resolve.
173 enum MalformedGenerics {
174 /// This link has unbalanced angle brackets.
176 /// For example, `Vec<T` should trigger this, as should `Vec<T>>`.
177 UnbalancedAngleBrackets,
178 /// The generics are not attached to a type.
180 /// For example, `<T>` should trigger this.
182 /// This is detected by checking if the path is empty after the generics are stripped.
184 /// The link uses fully-qualified syntax, which is currently unsupported.
186 /// For example, `<Vec as IntoIterator>::into_iter` should trigger this.
188 /// This is detected by checking if ` as ` (the keyword `as` with spaces around it) is inside
190 HasFullyQualifiedSyntax,
191 /// The link has an invalid path separator.
193 /// For example, `Vec:<T>:new()` should trigger this. Note that `Vec:new()` will **not**
194 /// trigger this because it has no generics and thus [`strip_generics_from_path`] will not be
197 /// Note that this will also **not** be triggered if the invalid path separator is inside angle
198 /// brackets because rustdoc mostly ignores what's inside angle brackets (except for
199 /// [`HasFullyQualifiedSyntax`](MalformedGenerics::HasFullyQualifiedSyntax)).
201 /// This is detected by checking if there is a colon followed by a non-colon in the link.
202 InvalidPathSeparator,
203 /// The link has too many angle brackets.
205 /// For example, `Vec<<T>>` should trigger this.
206 TooManyAngleBrackets,
207 /// The link has empty angle brackets.
209 /// For example, `Vec<>` should trigger this.
213 impl ResolutionFailure<'a> {
214 /// This resolved fully (not just partially) but is erroneous for some other reason
216 /// Returns the full resolution of the link, if present.
217 fn full_res(&self) -> Option<Res> {
219 Self::WrongNamespace { res, expected_ns: _ } => Some(*res),
226 /// User error: `[std#x#y]` is not valid
228 /// The anchor provided by the user conflicts with Rustdoc's generated anchor.
230 /// This is an unfortunate state of affairs. Not every item that can be
231 /// linked to has its own page; sometimes it is a subheading within a page,
232 /// like for associated items. In those cases, rustdoc uses an anchor to
233 /// link to the subheading. Since you can't have two anchors for the same
234 /// link, Rustdoc disallows having a user-specified anchor.
236 /// Most of the time this is fine, because you can just link to the page of
237 /// the item if you want to provide your own anchor.
238 RustdocAnchorConflict(Res),
241 #[derive(Clone, Debug, Hash, PartialEq, Eq)]
242 struct ResolutionInfo {
244 dis: Option<Disambiguator>,
246 extra_fragment: Option<String>,
250 struct DiagnosticInfo<'a> {
254 link_range: Range<usize>,
257 #[derive(Clone, Debug, Hash)]
259 pub res: (Res, Option<String>),
260 pub side_channel: Option<(DefKind, DefId)>,
263 struct LinkCollector<'a, 'tcx> {
264 cx: &'a mut DocContext<'tcx>,
265 /// A stack of modules used to decide what scope to resolve in.
267 /// The last module will be used if the parent scope of the current item is
270 /// This is used to store the kind of associated items,
271 /// because `clean` and the disambiguator code expect them to be different.
272 /// See the code for associated items on inherent impls for details.
273 kind_side_channel: Cell<Option<(DefKind, DefId)>>,
274 /// Cache the resolved links so we can avoid resolving (and emitting errors for) the same link.
275 /// The link will be `None` if it could not be resolved (i.e. the error was cached).
276 visited_links: FxHashMap<ResolutionInfo, Option<CachedLink>>,
279 impl<'a, 'tcx> LinkCollector<'a, 'tcx> {
280 /// Given a full link, parse it as an [enum struct variant].
282 /// In particular, this will return an error whenever there aren't three
283 /// full path segments left in the link.
285 /// [enum struct variant]: hir::VariantData::Struct
288 path_str: &'path str,
290 ) -> Result<(Res, Option<String>), ErrorKind<'path>> {
291 let tcx = self.cx.tcx;
292 let no_res = || ResolutionFailure::NotResolved {
295 unresolved: path_str.into(),
298 debug!("looking for enum variant {}", path_str);
299 let mut split = path_str.rsplitn(3, "::");
300 let (variant_field_str, variant_field_name) = split
302 .map(|f| (f, Symbol::intern(f)))
303 .expect("fold_item should ensure link is non-empty");
304 let (variant_str, variant_name) =
305 // we're not sure this is a variant at all, so use the full string
306 // If there's no second component, the link looks like `[path]`.
307 // So there's no partial res and we should say the whole link failed to resolve.
308 split.next().map(|f| (f, Symbol::intern(f))).ok_or_else(no_res)?;
311 .map(|f| f.to_owned())
312 // If there's no third component, we saw `[a::b]` before and it failed to resolve.
313 // So there's no partial res.
314 .ok_or_else(no_res)?;
317 .enter_resolver(|resolver| {
318 resolver.resolve_str_path_error(DUMMY_SP, &path, TypeNS, module_id)
320 .and_then(|(_, res)| res.try_into())
321 .map_err(|()| no_res())?;
324 Res::Def(DefKind::Enum, did) => {
328 .flat_map(|imp| tcx.associated_items(*imp).in_definition_order())
329 .any(|item| item.ident.name == variant_name)
331 // This is just to let `fold_item` know that this shouldn't be considered;
332 // it's a bug for the error to make it to the user
333 return Err(ResolutionFailure::Dummy.into());
335 match tcx.type_of(did).kind() {
336 ty::Adt(def, _) if def.is_enum() => {
337 if def.all_fields().any(|item| item.ident.name == variant_field_name) {
341 "variant.{}.field.{}",
342 variant_str, variant_field_name
346 Err(ResolutionFailure::NotResolved {
348 partial_res: Some(Res::Def(DefKind::Enum, def.did)),
349 unresolved: variant_field_str.into(),
357 _ => Err(ResolutionFailure::NotResolved {
359 partial_res: Some(ty_res),
360 unresolved: variant_str.into(),
366 /// Given a primitive type, try to resolve an associated item.
367 fn resolve_primitive_associated_item(
369 prim_ty: PrimitiveType,
372 ) -> Option<(Res, String, Option<(DefKind, DefId)>)> {
373 let tcx = self.cx.tcx;
375 prim_ty.impls(tcx).into_iter().find_map(|&impl_| {
376 tcx.associated_items(impl_)
377 .find_by_name_and_namespace(tcx, Ident::with_dummy_span(item_name), ns, impl_)
379 let kind = item.kind;
380 let out = match kind {
381 ty::AssocKind::Fn => "method",
382 ty::AssocKind::Const => "associatedconstant",
383 ty::AssocKind::Type => "associatedtype",
385 let fragment = format!("{}.{}", out, item_name);
386 (Res::Primitive(prim_ty), fragment, Some((kind.as_def_kind(), item.def_id)))
391 /// Resolves a string as a macro.
393 /// FIXME(jynelson): Can this be unified with `resolve()`?
398 ) -> Result<Res, ResolutionFailure<'a>> {
399 let path = ast::Path::from_ident(Ident::from_str(path_str));
400 self.cx.enter_resolver(|resolver| {
401 // FIXME(jynelson): does this really need 3 separate lookups?
402 if let Ok((Some(ext), res)) = resolver.resolve_macro_path(
405 &ParentScope::module(resolver.graph_root(), resolver),
409 if let SyntaxExtensionKind::LegacyBang { .. } = ext.kind {
410 return Ok(res.try_into().unwrap());
413 if let Some(&res) = resolver.all_macros().get(&Symbol::intern(path_str)) {
414 return Ok(res.try_into().unwrap());
416 debug!("resolving {} as a macro in the module {:?}", path_str, module_id);
417 if let Ok((_, res)) =
418 resolver.resolve_str_path_error(DUMMY_SP, path_str, MacroNS, module_id)
420 // don't resolve builtins like `#[derive]`
421 if let Ok(res) = res.try_into() {
425 Err(ResolutionFailure::NotResolved {
428 unresolved: path_str.into(),
433 /// Convenience wrapper around `resolve_str_path_error`.
435 /// This also handles resolving `true` and `false` as booleans.
436 /// NOTE: `resolve_str_path_error` knows only about paths, not about types.
437 /// Associated items will never be resolved by this function.
438 fn resolve_path(&self, path_str: &str, ns: Namespace, module_id: DefId) -> Option<Res> {
439 let result = self.cx.enter_resolver(|resolver| {
441 .resolve_str_path_error(DUMMY_SP, path_str, ns, module_id)
442 .and_then(|(_, res)| res.try_into())
444 debug!("{} resolved to {:?} in namespace {:?}", path_str, result, ns);
446 // resolver doesn't know about true, false, and types that aren't paths (e.g. `()`)
448 Err(()) => resolve_primitive(path_str, ns),
449 Ok(res) => Some(res),
453 /// Resolves a string as a path within a particular namespace. Returns an
454 /// optional URL fragment in the case of variants and methods.
457 path_str: &'path str,
460 extra_fragment: &Option<String>,
461 ) -> Result<(Res, Option<String>), ErrorKind<'path>> {
462 if let Some(res) = self.resolve_path(path_str, ns, module_id) {
464 // FIXME(#76467): make this fallthrough to lookup the associated
465 // item a separate function.
466 Res::Def(DefKind::AssocFn | DefKind::AssocConst, _) => assert_eq!(ns, ValueNS),
467 Res::Def(DefKind::AssocTy, _) => assert_eq!(ns, TypeNS),
468 Res::Def(DefKind::Variant, _) => {
469 return handle_variant(self.cx, res, extra_fragment);
471 // Not a trait item; just return what we found.
472 _ => return Ok((res, extra_fragment.clone())),
476 // Try looking for methods and associated items.
477 let mut split = path_str.rsplitn(2, "::");
478 // NB: `split`'s first element is always defined, even if the delimiter was not present.
479 // NB: `item_str` could be empty when resolving in the root namespace (e.g. `::std`).
480 let item_str = split.next().unwrap();
481 let item_name = Symbol::intern(item_str);
482 let path_root = split
484 .map(|f| f.to_owned())
485 // If there's no `::`, it's not an associated item.
486 // So we can be sure that `rustc_resolve` was accurate when it said it wasn't resolved.
488 debug!("found no `::`, assumming {} was correctly not in scope", item_name);
489 ResolutionFailure::NotResolved {
492 unresolved: item_str.into(),
496 // FIXME(#83862): this arbitrarily gives precedence to primitives over modules to support
497 // links to primitives when `#[doc(primitive)]` is present. It should give an ambiguity
498 // error instead and special case *only* modules with `#[doc(primitive)]`, not all
500 resolve_primitive(&path_root, TypeNS)
501 .or_else(|| self.resolve_path(&path_root, TypeNS, module_id))
503 let (res, fragment, side_channel) =
504 self.resolve_associated_item(ty_res, item_name, ns, module_id)?;
505 let result = if extra_fragment.is_some() {
506 // NOTE: can never be a primitive since `side_channel.is_none()` only when `res`
507 // is a trait (and the side channel DefId is always an associated item).
508 let diag_res = side_channel.map_or(res, |(k, r)| Res::Def(k, r));
509 Err(ErrorKind::AnchorFailure(AnchorFailure::RustdocAnchorConflict(diag_res)))
511 // HACK(jynelson): `clean` expects the type, not the associated item
512 // but the disambiguator logic expects the associated item.
513 // Store the kind in a side channel so that only the disambiguator logic looks at it.
514 if let Some((kind, id)) = side_channel {
515 self.kind_side_channel.set(Some((kind, id)));
517 Ok((res, Some(fragment)))
522 if ns == Namespace::ValueNS {
523 self.variant_field(path_str, module_id)
525 Err(ResolutionFailure::NotResolved {
528 unresolved: path_root.into(),
535 /// Convert a DefId to a Res, where possible.
537 /// This is used for resolving type aliases.
538 fn def_id_to_res(&self, ty_id: DefId) -> Option<Res> {
539 use PrimitiveType::*;
540 Some(match *self.cx.tcx.type_of(ty_id).kind() {
541 ty::Bool => Res::Primitive(Bool),
542 ty::Char => Res::Primitive(Char),
543 ty::Int(ity) => Res::Primitive(ity.into()),
544 ty::Uint(uty) => Res::Primitive(uty.into()),
545 ty::Float(fty) => Res::Primitive(fty.into()),
546 ty::Str => Res::Primitive(Str),
547 ty::Tuple(tys) if tys.is_empty() => Res::Primitive(Unit),
548 ty::Tuple(_) => Res::Primitive(Tuple),
549 ty::Array(..) => Res::Primitive(Array),
550 ty::Slice(_) => Res::Primitive(Slice),
551 ty::RawPtr(_) => Res::Primitive(RawPointer),
552 ty::Ref(..) => Res::Primitive(Reference),
553 ty::FnDef(..) => panic!("type alias to a function definition"),
554 ty::FnPtr(_) => Res::Primitive(Fn),
555 ty::Never => Res::Primitive(Never),
556 ty::Adt(&ty::AdtDef { did, .. }, _) | ty::Foreign(did) => {
557 Res::Def(self.cx.tcx.def_kind(did), did)
562 | ty::GeneratorWitness(_)
569 | ty::Error(_) => return None,
574 /// - None if no associated item was found
575 /// - Some((_, _, Some(_))) if an item was found and should go through a side channel
576 /// - Some((_, _, None)) otherwise
577 fn resolve_associated_item(
583 ) -> Option<(Res, String, Option<(DefKind, DefId)>)> {
584 let tcx = self.cx.tcx;
587 Res::Primitive(prim) => self.resolve_primitive_associated_item(prim, ns, item_name),
588 Res::Def(DefKind::TyAlias, did) => {
589 // Resolve the link on the type the alias points to.
590 // FIXME: if the associated item is defined directly on the type alias,
591 // it will show up on its documentation page, we should link there instead.
592 let res = self.def_id_to_res(did)?;
593 self.resolve_associated_item(res, item_name, ns, module_id)
596 DefKind::Struct | DefKind::Union | DefKind::Enum | DefKind::ForeignTy,
599 debug!("looking for associated item named {} for item {:?}", item_name, did);
600 // Checks if item_name belongs to `impl SomeItem`
605 tcx.associated_items(imp).find_by_name_and_namespace(
607 Ident::with_dummy_span(item_name),
612 .map(|item| (item.kind, item.def_id))
613 // There should only ever be one associated item that matches from any inherent impl
615 // Check if item_name belongs to `impl SomeTrait for SomeItem`
616 // FIXME(#74563): This gives precedence to `impl SomeItem`:
617 // Although having both would be ambiguous, use impl version for compatibility's sake.
618 // To handle that properly resolve() would have to support
619 // something like [`ambi_fn`](<SomeStruct as SomeTrait>::ambi_fn)
622 resolve_associated_trait_item(did, module_id, item_name, ns, self.cx);
623 debug!("got associated item kind {:?}", kind);
627 if let Some((kind, id)) = assoc_item {
628 let out = match kind {
629 ty::AssocKind::Fn => "method",
630 ty::AssocKind::Const => "associatedconstant",
631 ty::AssocKind::Type => "associatedtype",
633 // HACK(jynelson): `clean` expects the type, not the associated item
634 // but the disambiguator logic expects the associated item.
635 // Store the kind in a side channel so that only the disambiguator logic looks at it.
638 format!("{}.{}", out, item_name),
639 Some((kind.as_def_kind(), id)),
643 if ns != Namespace::ValueNS {
646 debug!("looking for variants or fields named {} for {:?}", item_name, did);
647 // FIXME: this doesn't really belong in `associated_item` (maybe `variant_field` is better?)
648 // NOTE: it's different from variant_field because it resolves fields and variants,
649 // not variant fields (2 path segments, not 3).
650 let def = match tcx.type_of(did).kind() {
651 ty::Adt(def, _) => def,
654 let field = if def.is_enum() {
655 def.all_fields().find(|item| item.ident.name == item_name)
657 def.non_enum_variant().fields.iter().find(|item| item.ident.name == item_name)
659 let kind = if def.is_enum() { DefKind::Variant } else { DefKind::Field };
664 if def.is_enum() { "variant" } else { "structfield" },
667 Some((kind, field.did)),
670 Res::Def(DefKind::Trait, did) => tcx
671 .associated_items(did)
672 .find_by_name_and_namespace(tcx, Ident::with_dummy_span(item_name), ns, did)
674 let kind = match item.kind {
675 ty::AssocKind::Const => "associatedconstant",
676 ty::AssocKind::Type => "associatedtype",
677 ty::AssocKind::Fn => {
678 if item.defaultness.has_value() {
686 let res = Res::Def(item.kind.as_def_kind(), item.def_id);
687 (res, format!("{}.{}", kind, item_name), None)
693 /// Used for reporting better errors.
695 /// Returns whether the link resolved 'fully' in another namespace.
696 /// 'fully' here means that all parts of the link resolved, not just some path segments.
697 /// This returns the `Res` even if it was erroneous for some reason
698 /// (such as having invalid URL fragments or being in the wrong namespace).
704 extra_fragment: &Option<String>,
706 // resolve() can't be used for macro namespace
707 let result = match ns {
708 Namespace::MacroNS => self.resolve_macro(path_str, module_id).map_err(ErrorKind::from),
709 Namespace::TypeNS | Namespace::ValueNS => {
710 self.resolve(path_str, ns, module_id, extra_fragment).map(|(res, _)| res)
714 let res = match result {
715 Ok(res) => Some(res),
716 Err(ErrorKind::Resolve(box kind)) => kind.full_res(),
717 Err(ErrorKind::AnchorFailure(AnchorFailure::RustdocAnchorConflict(res))) => Some(res),
718 Err(ErrorKind::AnchorFailure(AnchorFailure::MultipleAnchors)) => None,
720 self.kind_side_channel.take().map(|(kind, id)| Res::Def(kind, id)).or(res)
724 /// Look to see if a resolved item has an associated item named `item_name`.
726 /// Given `[std::io::Error::source]`, where `source` is unresolved, this would
727 /// find `std::error::Error::source` and return
728 /// `<io::Error as error::Error>::source`.
729 fn resolve_associated_trait_item(
734 cx: &mut DocContext<'_>,
735 ) -> Option<(ty::AssocKind, DefId)> {
736 // FIXME: this should also consider blanket impls (`impl<T> X for T`). Unfortunately
737 // `get_auto_trait_and_blanket_impls` is broken because the caching behavior is wrong. In the
738 // meantime, just don't look for these blanket impls.
740 // Next consider explicit impls: `impl MyTrait for MyType`
741 // Give precedence to inherent impls.
742 let traits = traits_implemented_by(cx, did, module);
743 debug!("considering traits {:?}", traits);
744 let mut candidates = traits.iter().filter_map(|&trait_| {
746 .associated_items(trait_)
747 .find_by_name_and_namespace(cx.tcx, Ident::with_dummy_span(item_name), ns, trait_)
748 .map(|assoc| (assoc.kind, assoc.def_id))
750 // FIXME(#74563): warn about ambiguity
751 debug!("the candidates were {:?}", candidates.clone().collect::<Vec<_>>());
755 /// Given a type, return all traits in scope in `module` implemented by that type.
757 /// NOTE: this cannot be a query because more traits could be available when more crates are compiled!
758 /// So it is not stable to serialize cross-crate.
759 fn traits_implemented_by(cx: &mut DocContext<'_>, type_: DefId, module: DefId) -> FxHashSet<DefId> {
760 let mut resolver = cx.resolver.borrow_mut();
761 let in_scope_traits = cx.module_trait_cache.entry(module).or_insert_with(|| {
762 resolver.access(|resolver| {
763 let parent_scope = &ParentScope::module(resolver.expect_module(module), resolver);
765 .traits_in_scope(None, parent_scope, SyntaxContext::root(), None)
767 .map(|candidate| candidate.def_id)
773 let ty = tcx.type_of(type_);
774 let iter = in_scope_traits.iter().flat_map(|&trait_| {
775 trace!("considering explicit impl for trait {:?}", trait_);
777 // Look at each trait implementation to see if it's an impl for `did`
778 tcx.find_map_relevant_impl(trait_, ty, |impl_| {
779 let trait_ref = tcx.impl_trait_ref(impl_).expect("this is not an inherent impl");
780 // Check if these are the same type.
781 let impl_type = trait_ref.self_ty();
783 "comparing type {} with kind {:?} against type {:?}",
788 // Fast path: if this is a primitive simple `==` will work
789 let saw_impl = impl_type == ty
790 || match impl_type.kind() {
791 // Check if these are the same def_id
793 debug!("adt def_id: {:?}", def.did);
796 ty::Foreign(def_id) => *def_id == type_,
800 if saw_impl { Some(trait_) } else { None }
806 /// Check for resolve collisions between a trait and its derive.
808 /// These are common and we should just resolve to the trait in that case.
809 fn is_derive_trait_collision<T>(ns: &PerNS<Result<(Res, T), ResolutionFailure<'_>>>) -> bool {
813 type_ns: Ok((Res::Def(DefKind::Trait, _), _)),
814 macro_ns: Ok((Res::Def(DefKind::Macro(MacroKind::Derive), _), _)),
820 impl<'a, 'tcx> DocVisitor for LinkCollector<'a, 'tcx> {
821 fn visit_item(&mut self, item: &Item) {
822 use rustc_middle::ty::DefIdTree;
825 item.def_id.as_def_id().and_then(|did| find_nearest_parent_module(self.cx.tcx, did));
826 if parent_node.is_some() {
827 trace!("got parent node for {:?} {:?}, id {:?}", item.type_(), item.name, item.def_id);
830 // find item's parent to resolve `Self` in item's docs below
831 debug!("looking for the `Self` type");
832 let self_id = match item.def_id.as_def_id() {
835 if (matches!(self.cx.tcx.def_kind(did), DefKind::Field)
837 self.cx.tcx.def_kind(self.cx.tcx.parent(did).unwrap()),
841 self.cx.tcx.parent(did).and_then(|item_id| self.cx.tcx.parent(item_id))
845 self.cx.tcx.def_kind(did),
853 self.cx.tcx.parent(did)
855 Some(did) => match self.cx.tcx.parent(did) {
856 // HACK(jynelson): `clean` marks associated types as `TypedefItem`, not as `AssocTypeItem`.
857 // Fixing this breaks `fn render_deref_methods`.
858 // As a workaround, see if the parent of the item is an `impl`; if so this must be an associated item,
859 // regardless of what rustdoc wants to call it.
861 let parent_kind = self.cx.tcx.def_kind(parent);
862 Some(if parent_kind == DefKind::Impl { parent } else { did })
868 // FIXME(jynelson): this shouldn't go through stringification, rustdoc should just use the DefId directly
869 let self_name = self_id.and_then(|self_id| {
870 if matches!(self.cx.tcx.def_kind(self_id), DefKind::Impl) {
871 // using `ty.to_string()` (or any variant) has issues with raw idents
872 let ty = self.cx.tcx.type_of(self_id);
873 let name = match ty.kind() {
874 ty::Adt(def, _) => Some(self.cx.tcx.item_name(def.did).to_string()),
875 other if other.is_primitive() => Some(ty.to_string()),
878 debug!("using type_of(): {:?}", name);
881 let name = self.cx.tcx.opt_item_name(self_id).map(|sym| sym.to_string());
882 debug!("using item_name(): {:?}", name);
887 let inner_docs = item.inner_docs(self.cx.tcx);
889 if item.is_mod() && inner_docs {
890 self.mod_ids.push(item.def_id.expect_def_id());
893 // We want to resolve in the lexical scope of the documentation.
894 // In the presence of re-exports, this is not the same as the module of the item.
895 // Rather than merging all documentation into one, resolve it one attribute at a time
896 // so we know which module it came from.
897 for (parent_module, doc) in item.attrs.collapsed_doc_value_by_module_level() {
898 debug!("combined_docs={}", doc);
900 let (krate, parent_node) = if let Some(id) = parent_module {
903 (item.def_id.krate(), parent_node)
905 // NOTE: if there are links that start in one crate and end in another, this will not resolve them.
906 // This is a degenerate case and it's not supported by rustdoc.
907 for md_link in markdown_links(&doc) {
908 let link = self.resolve_link(&item, &doc, &self_name, parent_node, krate, md_link);
909 if let Some(link) = link {
910 self.cx.cache.intra_doc_links.entry(item.def_id).or_default().push(link);
917 self.mod_ids.push(item.def_id.expect_def_id());
920 self.visit_item_recur(item);
923 self.visit_item_recur(item)
928 enum PreprocessingError<'a> {
929 Anchor(AnchorFailure),
930 Disambiguator(Range<usize>, String),
931 Resolution(ResolutionFailure<'a>, String, Option<Disambiguator>),
934 impl From<AnchorFailure> for PreprocessingError<'_> {
935 fn from(err: AnchorFailure) -> Self {
940 struct PreprocessingInfo {
942 disambiguator: Option<Disambiguator>,
943 extra_fragment: Option<String>,
948 /// - `None` if the link should be ignored.
949 /// - `Some(Err)` if the link should emit an error
950 /// - `Some(Ok)` if the link is valid
952 /// `link_buffer` is needed for lifetime reasons; it will always be overwritten and the contents ignored.
953 fn preprocess_link<'a>(
954 ori_link: &'a MarkdownLink,
955 ) -> Option<Result<PreprocessingInfo, PreprocessingError<'a>>> {
956 // [] is mostly likely not supposed to be a link
957 if ori_link.link.is_empty() {
961 // Bail early for real links.
962 if ori_link.link.contains('/') {
966 let stripped = ori_link.link.replace("`", "");
967 let mut parts = stripped.split('#');
969 let link = parts.next().unwrap();
970 if link.trim().is_empty() {
971 // This is an anchor to an element of the current page, nothing to do in here!
974 let extra_fragment = parts.next();
975 if parts.next().is_some() {
976 // A valid link can't have multiple #'s
977 return Some(Err(AnchorFailure::MultipleAnchors.into()));
980 // Parse and strip the disambiguator from the link, if present.
981 let (disambiguator, path_str, link_text) = match Disambiguator::from_str(link) {
982 Ok(Some((d, path, link_text))) => (Some(d), path.trim(), link_text.trim()),
983 Ok(None) => (None, link.trim(), link.trim()),
984 Err((err_msg, relative_range)) => {
985 // Only report error if we would not have ignored this link. See issue #83859.
986 if !should_ignore_link_with_disambiguators(link) {
987 let no_backticks_range = range_between_backticks(ori_link);
988 let disambiguator_range = (no_backticks_range.start + relative_range.start)
989 ..(no_backticks_range.start + relative_range.end);
990 return Some(Err(PreprocessingError::Disambiguator(disambiguator_range, err_msg)));
997 if should_ignore_link(path_str) {
1001 // Strip generics from the path.
1002 let path_str = if path_str.contains(['<', '>'].as_slice()) {
1003 match strip_generics_from_path(path_str) {
1006 debug!("link has malformed generics: {}", path_str);
1007 return Some(Err(PreprocessingError::Resolution(
1009 path_str.to_owned(),
1018 // Sanity check to make sure we don't have any angle brackets after stripping generics.
1019 assert!(!path_str.contains(['<', '>'].as_slice()));
1021 // The link is not an intra-doc link if it still contains spaces after stripping generics.
1022 if path_str.contains(' ') {
1026 Some(Ok(PreprocessingInfo {
1029 extra_fragment: extra_fragment.map(String::from),
1030 link_text: link_text.to_owned(),
1034 impl LinkCollector<'_, '_> {
1035 /// This is the entry point for resolving an intra-doc link.
1037 /// FIXME(jynelson): this is way too many arguments
1042 self_name: &Option<String>,
1043 parent_node: Option<DefId>,
1045 ori_link: MarkdownLink,
1046 ) -> Option<ItemLink> {
1047 trace!("considering link '{}'", ori_link.link);
1049 let diag_info = DiagnosticInfo {
1052 ori_link: &ori_link.link,
1053 link_range: ori_link.range.clone(),
1056 let PreprocessingInfo { path_str, disambiguator, extra_fragment, link_text } =
1057 match preprocess_link(&ori_link)? {
1061 PreprocessingError::Anchor(err) => anchor_failure(self.cx, diag_info, err),
1062 PreprocessingError::Disambiguator(range, msg) => {
1063 disambiguator_error(self.cx, diag_info, range, &msg)
1065 PreprocessingError::Resolution(err, path_str, disambiguator) => {
1078 let mut path_str = &*path_str;
1080 let inner_docs = item.inner_docs(self.cx.tcx);
1082 // In order to correctly resolve intra-doc links we need to
1083 // pick a base AST node to work from. If the documentation for
1084 // this module came from an inner comment (//!) then we anchor
1085 // our name resolution *inside* the module. If, on the other
1086 // hand it was an outer comment (///) then we anchor the name
1087 // resolution in the parent module on the basis that the names
1088 // used are more likely to be intended to be parent names. For
1089 // this, we set base_node to None for inner comments since
1090 // we've already pushed this node onto the resolution stack but
1091 // for outer comments we explicitly try and resolve against the
1092 // parent_node first.
1094 if item.is_mod() && inner_docs { self.mod_ids.last().copied() } else { parent_node };
1096 let mut module_id = if let Some(id) = base_node {
1100 debug!("attempting to resolve item without parent module: {}", path_str);
1106 smallvec![ResolutionFailure::NoParentItem],
1112 // replace `Self` with suitable item's parent name
1113 let is_lone_self = path_str == "Self";
1114 let is_lone_crate = path_str == "crate";
1115 if path_str.starts_with("Self::") || is_lone_self {
1116 if let Some(ref name) = self_name {
1120 resolved_self = format!("{}::{}", name, &path_str[6..]);
1121 path_str = &resolved_self;
1124 } else if path_str.starts_with("crate::") || is_lone_crate {
1125 use rustc_span::def_id::CRATE_DEF_INDEX;
1127 // HACK(jynelson): rustc_resolve thinks that `crate` is the crate currently being documented.
1128 // But rustdoc wants it to mean the crate this item was originally present in.
1129 // To work around this, remove it and resolve relative to the crate root instead.
1130 // HACK(jynelson)(2): If we just strip `crate::` then suddenly primitives become ambiguous
1131 // (consider `crate::char`). Instead, change it to `self::`. This works because 'self' is now the crate root.
1132 // FIXME(#78696): This doesn't always work.
1136 resolved_self = format!("self::{}", &path_str["crate::".len()..]);
1137 path_str = &resolved_self;
1139 module_id = DefId { krate, index: CRATE_DEF_INDEX };
1142 let (mut res, fragment) = self.resolve_with_disambiguator_cached(
1146 path_str: path_str.to_owned(),
1147 extra_fragment: extra_fragment.map(String::from),
1149 diag_info.clone(), // this struct should really be Copy, but Range is not :(
1150 matches!(ori_link.kind, LinkType::Reference | LinkType::Shortcut),
1153 // Check for a primitive which might conflict with a module
1154 // Report the ambiguity and require that the user specify which one they meant.
1155 // FIXME: could there ever be a primitive not in the type namespace?
1158 None | Some(Disambiguator::Namespace(Namespace::TypeNS) | Disambiguator::Primitive)
1159 ) && !matches!(res, Res::Primitive(_))
1161 if let Some(prim) = resolve_primitive(path_str, TypeNS) {
1163 if matches!(disambiguator, Some(Disambiguator::Primitive)) {
1166 // `[char]` when a `char` module is in scope
1167 let candidates = vec![res, prim];
1168 ambiguity_error(self.cx, diag_info, path_str, candidates);
1174 let report_mismatch = |specified: Disambiguator, resolved: Disambiguator| {
1175 // The resolved item did not match the disambiguator; give a better error than 'not found'
1176 let msg = format!("incompatible link kind for `{}`", path_str);
1177 let callback = |diag: &mut DiagnosticBuilder<'_>, sp: Option<rustc_span::Span>| {
1179 "this link resolved to {} {}, which is not {} {}",
1182 specified.article(),
1185 if let Some(sp) = sp {
1186 diag.span_label(sp, ¬e);
1190 suggest_disambiguator(resolved, diag, path_str, &ori_link.link, sp);
1192 report_diagnostic(self.cx.tcx, BROKEN_INTRA_DOC_LINKS, &msg, &diag_info, callback);
1195 let verify = |kind: DefKind, id: DefId| {
1196 let (kind, id) = self.kind_side_channel.take().unwrap_or((kind, id));
1197 debug!("intra-doc link to {} resolved to {:?} (id: {:?})", path_str, res, id);
1199 // Disallow e.g. linking to enums with `struct@`
1200 debug!("saw kind {:?} with disambiguator {:?}", kind, disambiguator);
1201 match (kind, disambiguator) {
1202 | (DefKind::Const | DefKind::ConstParam | DefKind::AssocConst | DefKind::AnonConst, Some(Disambiguator::Kind(DefKind::Const)))
1203 // NOTE: this allows 'method' to mean both normal functions and associated functions
1204 // This can't cause ambiguity because both are in the same namespace.
1205 | (DefKind::Fn | DefKind::AssocFn, Some(Disambiguator::Kind(DefKind::Fn)))
1206 // These are namespaces; allow anything in the namespace to match
1207 | (_, Some(Disambiguator::Namespace(_)))
1208 // If no disambiguator given, allow anything
1210 // All of these are valid, so do nothing
1212 (actual, Some(Disambiguator::Kind(expected))) if actual == expected => {}
1213 (_, Some(specified @ Disambiguator::Kind(_) | specified @ Disambiguator::Primitive)) => {
1214 report_mismatch(specified, Disambiguator::Kind(kind));
1219 // item can be non-local e.g. when using #[doc(primitive = "pointer")]
1220 if let Some((src_id, dst_id)) = id
1222 // The `expect_def_id()` should be okay because `local_def_id_to_hir_id`
1223 // would presumably panic if a fake `DefIndex` were passed.
1224 .and_then(|dst_id| {
1225 item.def_id.expect_def_id().as_local().map(|src_id| (src_id, dst_id))
1228 if self.cx.tcx.privacy_access_levels(()).is_exported(src_id)
1229 && !self.cx.tcx.privacy_access_levels(()).is_exported(dst_id)
1231 privacy_error(self.cx, &diag_info, path_str);
1239 Res::Primitive(prim) => {
1240 if let Some((kind, id)) = self.kind_side_channel.take() {
1241 // We're actually resolving an associated item of a primitive, so we need to
1242 // verify the disambiguator (if any) matches the type of the associated item.
1243 // This case should really follow the same flow as the `Res::Def` branch below,
1244 // but attempting to add a call to `clean::register_res` causes an ICE. @jyn514
1245 // thinks `register_res` is only needed for cross-crate re-exports, but Rust
1246 // doesn't allow statements like `use str::trim;`, making this a (hopefully)
1247 // valid omission. See https://github.com/rust-lang/rust/pull/80660#discussion_r551585677
1248 // for discussion on the matter.
1251 // FIXME: it would be nice to check that the feature gate was enabled in the original crate, not just ignore it altogether.
1252 // However I'm not sure how to check that across crates.
1253 if prim == PrimitiveType::RawPointer
1254 && item.def_id.is_local()
1255 && !self.cx.tcx.features().intra_doc_pointers
1257 let span = super::source_span_for_markdown_range(
1263 .unwrap_or_else(|| item.attr_span(self.cx.tcx));
1265 rustc_session::parse::feature_err(
1266 &self.cx.tcx.sess.parse_sess,
1267 sym::intra_doc_pointers,
1269 "linking to associated items of raw pointers is experimental",
1271 .note("rustdoc does not allow disambiguating between `*const` and `*mut`, and pointers are unstable until it does")
1275 match disambiguator {
1276 Some(Disambiguator::Primitive | Disambiguator::Namespace(_)) | None => {}
1278 report_mismatch(other, Disambiguator::Primitive);
1285 link: ori_link.link,
1287 did: res.def_id(self.cx.tcx),
1291 Res::Def(kind, id) => {
1293 let id = clean::register_res(self.cx, rustc_hir::def::Res::Def(kind, id));
1294 Some(ItemLink { link: ori_link.link, link_text, did: id, fragment })
1299 fn resolve_with_disambiguator_cached(
1301 key: ResolutionInfo,
1302 diag: DiagnosticInfo<'_>,
1303 cache_resolution_failure: bool,
1304 ) -> Option<(Res, Option<String>)> {
1305 // Try to look up both the result and the corresponding side channel value
1306 if let Some(ref cached) = self.visited_links.get(&key) {
1309 self.kind_side_channel.set(cached.side_channel);
1310 return Some(cached.res.clone());
1312 None if cache_resolution_failure => return None,
1314 // Although we hit the cache and found a resolution error, this link isn't
1315 // supposed to cache those. Run link resolution again to emit the expected
1316 // resolution error.
1321 let res = self.resolve_with_disambiguator(&key, diag);
1323 // Cache only if resolved successfully - don't silence duplicate errors
1324 if let Some(res) = res {
1325 // Store result for the actual namespace
1326 self.visited_links.insert(
1330 side_channel: self.kind_side_channel.clone().into_inner(),
1336 if cache_resolution_failure {
1337 // For reference-style links we only want to report one resolution error
1338 // so let's cache them as well.
1339 self.visited_links.insert(key, None);
1346 /// After parsing the disambiguator, resolve the main part of the link.
1347 // FIXME(jynelson): wow this is just so much
1348 fn resolve_with_disambiguator(
1350 key: &ResolutionInfo,
1351 diag: DiagnosticInfo<'_>,
1352 ) -> Option<(Res, Option<String>)> {
1353 let disambiguator = key.dis;
1354 let path_str = &key.path_str;
1355 let base_node = key.module_id;
1356 let extra_fragment = &key.extra_fragment;
1358 match disambiguator.map(Disambiguator::ns) {
1359 Some(expected_ns @ (ValueNS | TypeNS)) => {
1360 match self.resolve(path_str, expected_ns, base_node, extra_fragment) {
1361 Ok(res) => Some(res),
1362 Err(ErrorKind::Resolve(box mut kind)) => {
1363 // We only looked in one namespace. Try to give a better error if possible.
1364 if kind.full_res().is_none() {
1365 let other_ns = if expected_ns == ValueNS { TypeNS } else { ValueNS };
1366 // FIXME: really it should be `resolution_failure` that does this, not `resolve_with_disambiguator`
1367 // See https://github.com/rust-lang/rust/pull/76955#discussion_r493953382 for a good approach
1368 for new_ns in [other_ns, MacroNS] {
1370 self.check_full_res(new_ns, path_str, base_node, extra_fragment)
1372 kind = ResolutionFailure::WrongNamespace { res, expected_ns };
1377 resolution_failure(self, diag, path_str, disambiguator, smallvec![kind]);
1378 // This could just be a normal link or a broken link
1379 // we could potentially check if something is
1380 // "intra-doc-link-like" and warn in that case.
1383 Err(ErrorKind::AnchorFailure(msg)) => {
1384 anchor_failure(self.cx, diag, msg);
1391 let mut candidates = PerNS {
1393 .resolve_macro(path_str, base_node)
1394 .map(|res| (res, extra_fragment.clone())),
1395 type_ns: match self.resolve(path_str, TypeNS, base_node, extra_fragment) {
1397 debug!("got res in TypeNS: {:?}", res);
1400 Err(ErrorKind::AnchorFailure(msg)) => {
1401 anchor_failure(self.cx, diag, msg);
1404 Err(ErrorKind::Resolve(box kind)) => Err(kind),
1406 value_ns: match self.resolve(path_str, ValueNS, base_node, extra_fragment) {
1408 Err(ErrorKind::AnchorFailure(msg)) => {
1409 anchor_failure(self.cx, diag, msg);
1412 Err(ErrorKind::Resolve(box kind)) => Err(kind),
1414 .and_then(|(res, fragment)| {
1415 // Constructors are picked up in the type namespace.
1417 Res::Def(DefKind::Ctor(..), _) => {
1418 Err(ResolutionFailure::WrongNamespace { res, expected_ns: TypeNS })
1421 match (fragment, extra_fragment.clone()) {
1422 (Some(fragment), Some(_)) => {
1423 // Shouldn't happen but who knows?
1424 Ok((res, Some(fragment)))
1426 (fragment, None) | (None, fragment) => Ok((res, fragment)),
1433 let len = candidates.iter().filter(|res| res.is_ok()).count();
1441 candidates.into_iter().filter_map(|res| res.err()).collect(),
1443 // this could just be a normal link
1448 Some(candidates.into_iter().find_map(|res| res.ok()).unwrap())
1449 } else if len == 2 && is_derive_trait_collision(&candidates) {
1450 Some(candidates.type_ns.unwrap())
1452 if is_derive_trait_collision(&candidates) {
1453 candidates.macro_ns = Err(ResolutionFailure::Dummy);
1455 // If we're reporting an ambiguity, don't mention the namespaces that failed
1456 let candidates = candidates.map(|candidate| candidate.ok().map(|(res, _)| res));
1457 ambiguity_error(self.cx, diag, path_str, candidates.present_items().collect());
1462 match self.resolve_macro(path_str, base_node) {
1463 Ok(res) => Some((res, extra_fragment.clone())),
1465 // `resolve_macro` only looks in the macro namespace. Try to give a better error if possible.
1466 for ns in [TypeNS, ValueNS] {
1468 self.check_full_res(ns, path_str, base_node, extra_fragment)
1471 ResolutionFailure::WrongNamespace { res, expected_ns: MacroNS };
1475 resolution_failure(self, diag, path_str, disambiguator, smallvec![kind]);
1484 /// Get the section of a link between the backticks,
1485 /// or the whole link if there aren't any backticks.
1493 fn range_between_backticks(ori_link: &MarkdownLink) -> Range<usize> {
1494 let after_first_backtick_group = ori_link.link.bytes().position(|b| b != b'`').unwrap_or(0);
1495 let before_second_backtick_group = ori_link
1498 .skip(after_first_backtick_group)
1499 .position(|b| b == b'`')
1500 .unwrap_or(ori_link.link.len());
1501 (ori_link.range.start + after_first_backtick_group)
1502 ..(ori_link.range.start + before_second_backtick_group)
1505 /// Returns true if we should ignore `link` due to it being unlikely
1506 /// that it is an intra-doc link. `link` should still have disambiguators
1507 /// if there were any.
1509 /// The difference between this and [`should_ignore_link()`] is that this
1510 /// check should only be used on links that still have disambiguators.
1511 fn should_ignore_link_with_disambiguators(link: &str) -> bool {
1512 link.contains(|ch: char| !(ch.is_alphanumeric() || ":_<>, !*&;@()".contains(ch)))
1515 /// Returns true if we should ignore `path_str` due to it being unlikely
1516 /// that it is an intra-doc link.
1517 fn should_ignore_link(path_str: &str) -> bool {
1518 path_str.contains(|ch: char| !(ch.is_alphanumeric() || ":_<>, !*&;".contains(ch)))
1521 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1522 /// Disambiguators for a link.
1523 enum Disambiguator {
1526 /// This is buggy, see <https://github.com/rust-lang/rust/pull/77875#discussion_r503583103>
1528 /// `struct@` or `f()`
1531 Namespace(Namespace),
1534 impl Disambiguator {
1535 /// Given a link, parse and return `(disambiguator, path_str, link_text)`.
1537 /// This returns `Ok(Some(...))` if a disambiguator was found,
1538 /// `Ok(None)` if no disambiguator was found, or `Err(...)`
1539 /// if there was a problem with the disambiguator.
1540 fn from_str(link: &str) -> Result<Option<(Self, &str, &str)>, (String, Range<usize>)> {
1541 use Disambiguator::{Kind, Namespace as NS, Primitive};
1543 if let Some(idx) = link.find('@') {
1544 let (prefix, rest) = link.split_at(idx);
1545 let d = match prefix {
1546 "struct" => Kind(DefKind::Struct),
1547 "enum" => Kind(DefKind::Enum),
1548 "trait" => Kind(DefKind::Trait),
1549 "union" => Kind(DefKind::Union),
1550 "module" | "mod" => Kind(DefKind::Mod),
1551 "const" | "constant" => Kind(DefKind::Const),
1552 "static" => Kind(DefKind::Static),
1553 "function" | "fn" | "method" => Kind(DefKind::Fn),
1554 "derive" => Kind(DefKind::Macro(MacroKind::Derive)),
1555 "type" => NS(Namespace::TypeNS),
1556 "value" => NS(Namespace::ValueNS),
1557 "macro" => NS(Namespace::MacroNS),
1558 "prim" | "primitive" => Primitive,
1559 _ => return Err((format!("unknown disambiguator `{}`", prefix), 0..idx)),
1561 Ok(Some((d, &rest[1..], &rest[1..])))
1564 ("!()", DefKind::Macro(MacroKind::Bang)),
1565 ("!{}", DefKind::Macro(MacroKind::Bang)),
1566 ("![]", DefKind::Macro(MacroKind::Bang)),
1567 ("()", DefKind::Fn),
1568 ("!", DefKind::Macro(MacroKind::Bang)),
1570 for (suffix, kind) in suffixes {
1571 if let Some(path_str) = link.strip_suffix(suffix) {
1572 // Avoid turning `!` or `()` into an empty string
1573 if !path_str.is_empty() {
1574 return Ok(Some((Kind(kind), path_str, link)));
1582 fn from_res(res: Res) -> Self {
1584 Res::Def(kind, _) => Disambiguator::Kind(kind),
1585 Res::Primitive(_) => Disambiguator::Primitive,
1589 /// Used for error reporting.
1590 fn suggestion(self) -> Suggestion {
1591 let kind = match self {
1592 Disambiguator::Primitive => return Suggestion::Prefix("prim"),
1593 Disambiguator::Kind(kind) => kind,
1594 Disambiguator::Namespace(_) => panic!("display_for cannot be used on namespaces"),
1596 if kind == DefKind::Macro(MacroKind::Bang) {
1597 return Suggestion::Macro;
1598 } else if kind == DefKind::Fn || kind == DefKind::AssocFn {
1599 return Suggestion::Function;
1600 } else if kind == DefKind::Field {
1601 return Suggestion::RemoveDisambiguator;
1604 let prefix = match kind {
1605 DefKind::Struct => "struct",
1606 DefKind::Enum => "enum",
1607 DefKind::Trait => "trait",
1608 DefKind::Union => "union",
1609 DefKind::Mod => "mod",
1610 DefKind::Const | DefKind::ConstParam | DefKind::AssocConst | DefKind::AnonConst => {
1613 DefKind::Static => "static",
1614 DefKind::Macro(MacroKind::Derive) => "derive",
1615 // Now handle things that don't have a specific disambiguator
1618 .expect("tried to calculate a disambiguator for a def without a namespace?")
1620 Namespace::TypeNS => "type",
1621 Namespace::ValueNS => "value",
1622 Namespace::MacroNS => "macro",
1626 Suggestion::Prefix(prefix)
1629 fn ns(self) -> Namespace {
1631 Self::Namespace(n) => n,
1633 k.ns().expect("only DefKinds with a valid namespace can be disambiguators")
1635 Self::Primitive => TypeNS,
1639 fn article(self) -> &'static str {
1641 Self::Namespace(_) => panic!("article() doesn't make sense for namespaces"),
1642 Self::Kind(k) => k.article(),
1643 Self::Primitive => "a",
1647 fn descr(self) -> &'static str {
1649 Self::Namespace(n) => n.descr(),
1650 // HACK(jynelson): by looking at the source I saw the DefId we pass
1651 // for `expected.descr()` doesn't matter, since it's not a crate
1652 Self::Kind(k) => k.descr(DefId::local(hir::def_id::DefIndex::from_usize(0))),
1653 Self::Primitive => "builtin type",
1658 /// A suggestion to show in a diagnostic.
1661 Prefix(&'static str),
1666 /// `foo` without any disambiguator
1667 RemoveDisambiguator,
1671 fn descr(&self) -> Cow<'static, str> {
1673 Self::Prefix(x) => format!("prefix with `{}@`", x).into(),
1674 Self::Function => "add parentheses".into(),
1675 Self::Macro => "add an exclamation mark".into(),
1676 Self::RemoveDisambiguator => "remove the disambiguator".into(),
1680 fn as_help(&self, path_str: &str) -> String {
1681 // FIXME: if this is an implied shortcut link, it's bad style to suggest `@`
1683 Self::Prefix(prefix) => format!("{}@{}", prefix, path_str),
1684 Self::Function => format!("{}()", path_str),
1685 Self::Macro => format!("{}!", path_str),
1686 Self::RemoveDisambiguator => path_str.into(),
1694 sp: rustc_span::Span,
1695 ) -> Vec<(rustc_span::Span, String)> {
1696 let inner_sp = match ori_link.find('(') {
1697 Some(index) => sp.with_hi(sp.lo() + BytePos(index as _)),
1700 let inner_sp = match ori_link.find('!') {
1701 Some(index) => inner_sp.with_hi(inner_sp.lo() + BytePos(index as _)),
1704 let inner_sp = match ori_link.find('@') {
1705 Some(index) => inner_sp.with_lo(inner_sp.lo() + BytePos(index as u32 + 1)),
1709 Self::Prefix(prefix) => {
1710 // FIXME: if this is an implied shortcut link, it's bad style to suggest `@`
1711 let mut sugg = vec![(sp.with_hi(inner_sp.lo()), format!("{}@", prefix))];
1712 if sp.hi() != inner_sp.hi() {
1713 sugg.push((inner_sp.shrink_to_hi().with_hi(sp.hi()), String::new()));
1718 let mut sugg = vec![(inner_sp.shrink_to_hi().with_hi(sp.hi()), "()".to_string())];
1719 if sp.lo() != inner_sp.lo() {
1720 sugg.push((inner_sp.shrink_to_lo().with_lo(sp.lo()), String::new()));
1725 let mut sugg = vec![(inner_sp.shrink_to_hi(), "!".to_string())];
1726 if sp.lo() != inner_sp.lo() {
1727 sugg.push((inner_sp.shrink_to_lo().with_lo(sp.lo()), String::new()));
1731 Self::RemoveDisambiguator => return vec![(sp, path_str.into())],
1736 /// Reports a diagnostic for an intra-doc link.
1738 /// If no link range is provided, or the source span of the link cannot be determined, the span of
1739 /// the entire documentation block is used for the lint. If a range is provided but the span
1740 /// calculation fails, a note is added to the diagnostic pointing to the link in the markdown.
1742 /// The `decorate` callback is invoked in all cases to allow further customization of the
1743 /// diagnostic before emission. If the span of the link was able to be determined, the second
1744 /// parameter of the callback will contain it, and the primary span of the diagnostic will be set
1746 fn report_diagnostic(
1748 lint: &'static Lint,
1750 DiagnosticInfo { item, ori_link: _, dox, link_range }: &DiagnosticInfo<'_>,
1751 decorate: impl FnOnce(&mut DiagnosticBuilder<'_>, Option<rustc_span::Span>),
1753 let hir_id = match DocContext::as_local_hir_id(tcx, item.def_id) {
1754 Some(hir_id) => hir_id,
1756 // If non-local, no need to check anything.
1757 info!("ignoring warning from parent crate: {}", msg);
1762 let sp = item.attr_span(tcx);
1764 tcx.struct_span_lint_hir(lint, hir_id, sp, |lint| {
1765 let mut diag = lint.build(msg);
1768 super::source_span_for_markdown_range(tcx, dox, link_range, &item.attrs).map(|sp| {
1769 if dox.as_bytes().get(link_range.start) == Some(&b'`')
1770 && dox.as_bytes().get(link_range.end - 1) == Some(&b'`')
1772 sp.with_lo(sp.lo() + BytePos(1)).with_hi(sp.hi() - BytePos(1))
1778 if let Some(sp) = span {
1781 // blah blah blah\nblah\nblah [blah] blah blah\nblah blah
1784 // last_new_line_offset
1785 let last_new_line_offset = dox[..link_range.start].rfind('\n').map_or(0, |n| n + 1);
1786 let line = dox[last_new_line_offset..].lines().next().unwrap_or("");
1788 // Print the line containing the `link_range` and manually mark it with '^'s.
1790 "the link appears in this line:\n\n{line}\n\
1791 {indicator: <before$}{indicator:^<found$}",
1794 before = link_range.start - last_new_line_offset,
1795 found = link_range.len(),
1799 decorate(&mut diag, span);
1805 /// Reports a link that failed to resolve.
1807 /// This also tries to resolve any intermediate path segments that weren't
1808 /// handled earlier. For example, if passed `Item::Crate(std)` and `path_str`
1809 /// `std::io::Error::x`, this will resolve `std::io::Error`.
1810 fn resolution_failure(
1811 collector: &mut LinkCollector<'_, '_>,
1812 diag_info: DiagnosticInfo<'_>,
1814 disambiguator: Option<Disambiguator>,
1815 kinds: SmallVec<[ResolutionFailure<'_>; 3]>,
1817 let tcx = collector.cx.tcx;
1820 BROKEN_INTRA_DOC_LINKS,
1821 &format!("unresolved link to `{}`", path_str),
1824 let item = |res: Res| format!("the {} `{}`", res.descr(), res.name(tcx),);
1825 let assoc_item_not_allowed = |res: Res| {
1826 let name = res.name(tcx);
1828 "`{}` is {} {}, not a module or type, and cannot have associated items",
1834 // ignore duplicates
1835 let mut variants_seen = SmallVec::<[_; 3]>::new();
1836 for mut failure in kinds {
1837 let variant = std::mem::discriminant(&failure);
1838 if variants_seen.contains(&variant) {
1841 variants_seen.push(variant);
1843 if let ResolutionFailure::NotResolved { module_id, partial_res, unresolved } =
1848 let module_id = *module_id;
1849 // FIXME(jynelson): this might conflict with my `Self` fix in #76467
1850 // FIXME: maybe use itertools `collect_tuple` instead?
1851 fn split(path: &str) -> Option<(&str, &str)> {
1852 let mut splitter = path.rsplitn(2, "::");
1853 splitter.next().and_then(|right| splitter.next().map(|left| (left, right)))
1856 // Check if _any_ parent of the path gets resolved.
1857 // If so, report it and say the first which failed; if not, say the first path segment didn't resolve.
1858 let mut name = path_str;
1860 let (start, end) = if let Some(x) = split(name) {
1863 // avoid bug that marked [Quux::Z] as missing Z, not Quux
1864 if partial_res.is_none() {
1865 *unresolved = name.into();
1870 for ns in [TypeNS, ValueNS, MacroNS] {
1871 if let Some(res) = collector.check_full_res(ns, start, module_id, &None)
1873 debug!("found partial_res={:?}", res);
1874 *partial_res = Some(res);
1875 *unresolved = end.into();
1879 *unresolved = end.into();
1882 let last_found_module = match *partial_res {
1883 Some(Res::Def(DefKind::Mod, id)) => Some(id),
1884 None => Some(module_id),
1887 // See if this was a module: `[path]` or `[std::io::nope]`
1888 if let Some(module) = last_found_module {
1889 let note = if partial_res.is_some() {
1890 // Part of the link resolved; e.g. `std::io::nonexistent`
1891 let module_name = tcx.item_name(module);
1892 format!("no item named `{}` in module `{}`", unresolved, module_name)
1894 // None of the link resolved; e.g. `Notimported`
1895 format!("no item named `{}` in scope", unresolved)
1897 if let Some(span) = sp {
1898 diag.span_label(span, ¬e);
1903 // If the link has `::` in it, assume it was meant to be an intra-doc link.
1904 // Otherwise, the `[]` might be unrelated.
1905 // FIXME: don't show this for autolinks (`<>`), `()` style links, or reference links
1906 if !path_str.contains("::") {
1907 diag.help(r#"to escape `[` and `]` characters, add '\' before them like `\[` or `\]`"#);
1913 // Otherwise, it must be an associated item or variant
1914 let res = partial_res.expect("None case was handled by `last_found_module`");
1915 let name = res.name(tcx);
1916 let kind = match res {
1917 Res::Def(kind, _) => Some(kind),
1918 Res::Primitive(_) => None,
1920 let path_description = if let Some(kind) = kind {
1922 Mod | ForeignMod => "inner item",
1923 Struct => "field or associated item",
1924 Enum | Union => "variant or associated item",
1942 let note = assoc_item_not_allowed(res);
1943 if let Some(span) = sp {
1944 diag.span_label(span, ¬e);
1950 Trait | TyAlias | ForeignTy | OpaqueTy | TraitAlias | TyParam
1951 | Static => "associated item",
1952 Impl | GlobalAsm => unreachable!("not a path"),
1958 "the {} `{}` has no {} named `{}`",
1961 disambiguator.map_or(path_description, |d| d.descr()),
1964 if let Some(span) = sp {
1965 diag.span_label(span, ¬e);
1972 let note = match failure {
1973 ResolutionFailure::NotResolved { .. } => unreachable!("handled above"),
1974 ResolutionFailure::Dummy => continue,
1975 ResolutionFailure::WrongNamespace { res, expected_ns } => {
1976 if let Res::Def(kind, _) = res {
1977 let disambiguator = Disambiguator::Kind(kind);
1978 suggest_disambiguator(
1988 "this link resolves to {}, which is not in the {} namespace",
1993 ResolutionFailure::NoParentItem => {
1994 diag.level = rustc_errors::Level::Bug;
1995 "all intra-doc links should have a parent item".to_owned()
1997 ResolutionFailure::MalformedGenerics(variant) => match variant {
1998 MalformedGenerics::UnbalancedAngleBrackets => {
1999 String::from("unbalanced angle brackets")
2001 MalformedGenerics::MissingType => {
2002 String::from("missing type for generic parameters")
2004 MalformedGenerics::HasFullyQualifiedSyntax => {
2005 diag.note("see https://github.com/rust-lang/rust/issues/74563 for more information");
2006 String::from("fully-qualified syntax is unsupported")
2008 MalformedGenerics::InvalidPathSeparator => {
2009 String::from("has invalid path separator")
2011 MalformedGenerics::TooManyAngleBrackets => {
2012 String::from("too many angle brackets")
2014 MalformedGenerics::EmptyAngleBrackets => {
2015 String::from("empty angle brackets")
2019 if let Some(span) = sp {
2020 diag.span_label(span, ¬e);
2029 /// Report an anchor failure.
2030 fn anchor_failure(cx: &DocContext<'_>, diag_info: DiagnosticInfo<'_>, failure: AnchorFailure) {
2031 let (msg, anchor_idx) = match failure {
2032 AnchorFailure::MultipleAnchors => {
2033 (format!("`{}` contains multiple anchors", diag_info.ori_link), 1)
2035 AnchorFailure::RustdocAnchorConflict(res) => (
2037 "`{}` contains an anchor, but links to {kind}s are already anchored",
2045 report_diagnostic(cx.tcx, BROKEN_INTRA_DOC_LINKS, &msg, &diag_info, |diag, sp| {
2046 if let Some(mut sp) = sp {
2047 if let Some((fragment_offset, _)) =
2048 diag_info.ori_link.char_indices().filter(|(_, x)| *x == '#').nth(anchor_idx)
2050 sp = sp.with_lo(sp.lo() + BytePos(fragment_offset as _));
2052 diag.span_label(sp, "invalid anchor");
2054 if let AnchorFailure::RustdocAnchorConflict(Res::Primitive(_)) = failure {
2055 if let Some(sp) = sp {
2056 span_bug!(sp, "anchors should be allowed now");
2058 bug!("anchors should be allowed now");
2064 /// Report an error in the link disambiguator.
2065 fn disambiguator_error(
2066 cx: &DocContext<'_>,
2067 mut diag_info: DiagnosticInfo<'_>,
2068 disambiguator_range: Range<usize>,
2071 diag_info.link_range = disambiguator_range;
2072 report_diagnostic(cx.tcx, BROKEN_INTRA_DOC_LINKS, msg, &diag_info, |diag, _sp| {
2074 "see {}/rustdoc/linking-to-items-by-name.html#namespaces-and-disambiguators for more info about disambiguators",
2075 crate::DOC_RUST_LANG_ORG_CHANNEL
2081 /// Report an ambiguity error, where there were multiple possible resolutions.
2083 cx: &DocContext<'_>,
2084 diag_info: DiagnosticInfo<'_>,
2086 candidates: Vec<Res>,
2088 let mut msg = format!("`{}` is ", path_str);
2090 match candidates.as_slice() {
2091 [first_def, second_def] => {
2093 "both {} {} and {} {}",
2094 first_def.article(),
2096 second_def.article(),
2101 let mut candidates = candidates.iter().peekable();
2102 while let Some(res) = candidates.next() {
2103 if candidates.peek().is_some() {
2104 msg += &format!("{} {}, ", res.article(), res.descr());
2106 msg += &format!("and {} {}", res.article(), res.descr());
2112 report_diagnostic(cx.tcx, BROKEN_INTRA_DOC_LINKS, &msg, &diag_info, |diag, sp| {
2113 if let Some(sp) = sp {
2114 diag.span_label(sp, "ambiguous link");
2116 diag.note("ambiguous link");
2119 for res in candidates {
2120 let disambiguator = Disambiguator::from_res(res);
2121 suggest_disambiguator(disambiguator, diag, path_str, diag_info.ori_link, sp);
2126 /// In case of an ambiguity or mismatched disambiguator, suggest the correct
2128 fn suggest_disambiguator(
2129 disambiguator: Disambiguator,
2130 diag: &mut DiagnosticBuilder<'_>,
2133 sp: Option<rustc_span::Span>,
2135 let suggestion = disambiguator.suggestion();
2136 let help = format!("to link to the {}, {}", disambiguator.descr(), suggestion.descr());
2138 if let Some(sp) = sp {
2139 let mut spans = suggestion.as_help_span(path_str, ori_link, sp);
2140 if spans.len() > 1 {
2141 diag.multipart_suggestion(&help, spans, Applicability::MaybeIncorrect);
2143 let (sp, suggestion_text) = spans.pop().unwrap();
2144 diag.span_suggestion_verbose(sp, &help, suggestion_text, Applicability::MaybeIncorrect);
2147 diag.help(&format!("{}: {}", help, suggestion.as_help(path_str)));
2151 /// Report a link from a public item to a private one.
2152 fn privacy_error(cx: &DocContext<'_>, diag_info: &DiagnosticInfo<'_>, path_str: &str) {
2154 let item_name = match diag_info.item.name {
2156 sym = name.as_str();
2159 None => "<unknown>",
2162 format!("public documentation for `{}` links to private item `{}`", item_name, path_str);
2164 report_diagnostic(cx.tcx, PRIVATE_INTRA_DOC_LINKS, &msg, diag_info, |diag, sp| {
2165 if let Some(sp) = sp {
2166 diag.span_label(sp, "this item is private");
2169 let note_msg = if cx.render_options.document_private {
2170 "this link resolves only because you passed `--document-private-items`, but will break without"
2172 "this link will resolve properly if you pass `--document-private-items`"
2174 diag.note(note_msg);
2178 /// Given an enum variant's res, return the res of its enum and the associated fragment.
2180 cx: &DocContext<'_>,
2182 extra_fragment: &Option<String>,
2183 ) -> Result<(Res, Option<String>), ErrorKind<'static>> {
2184 use rustc_middle::ty::DefIdTree;
2186 if extra_fragment.is_some() {
2187 // NOTE: `res` can never be a primitive since this function is only called when `tcx.def_kind(res) == DefKind::Variant`.
2188 return Err(ErrorKind::AnchorFailure(AnchorFailure::RustdocAnchorConflict(res)));
2191 .parent(res.def_id(cx.tcx))
2193 let parent_def = Res::Def(DefKind::Enum, parent);
2194 let variant = cx.tcx.expect_variant_res(res.as_hir_res().unwrap());
2195 (parent_def, Some(format!("variant.{}", variant.ident.name)))
2197 .ok_or_else(|| ResolutionFailure::NoParentItem.into())
2200 /// Resolve a primitive type or value.
2201 fn resolve_primitive(path_str: &str, ns: Namespace) -> Option<Res> {
2205 use PrimitiveType::*;
2206 let prim = match path_str {
2222 "bool" | "true" | "false" => Bool,
2223 "str" | "&str" => Str,
2224 // See #80181 for why these don't have symbols associated.
2229 "pointer" | "*const" | "*mut" => RawPointer,
2230 "reference" | "&" | "&mut" => Reference,
2232 "never" | "!" => Never,
2235 debug!("resolved primitives {:?}", prim);
2236 Some(Res::Primitive(prim))
2239 fn strip_generics_from_path(path_str: &str) -> Result<String, ResolutionFailure<'static>> {
2240 let mut stripped_segments = vec![];
2241 let mut path = path_str.chars().peekable();
2242 let mut segment = Vec::new();
2244 while let Some(chr) = path.next() {
2247 if path.next_if_eq(&':').is_some() {
2248 let stripped_segment =
2249 strip_generics_from_path_segment(mem::take(&mut segment))?;
2250 if !stripped_segment.is_empty() {
2251 stripped_segments.push(stripped_segment);
2254 return Err(ResolutionFailure::MalformedGenerics(
2255 MalformedGenerics::InvalidPathSeparator,
2264 return Err(ResolutionFailure::MalformedGenerics(
2265 MalformedGenerics::TooManyAngleBrackets,
2269 return Err(ResolutionFailure::MalformedGenerics(
2270 MalformedGenerics::EmptyAngleBrackets,
2276 while let Some(chr) = path.next_if(|c| *c != '>') {
2283 _ => segment.push(chr),
2285 trace!("raw segment: {:?}", segment);
2288 if !segment.is_empty() {
2289 let stripped_segment = strip_generics_from_path_segment(segment)?;
2290 if !stripped_segment.is_empty() {
2291 stripped_segments.push(stripped_segment);
2295 debug!("path_str: {:?}\nstripped segments: {:?}", path_str, &stripped_segments);
2297 let stripped_path = stripped_segments.join("::");
2299 if !stripped_path.is_empty() {
2302 Err(ResolutionFailure::MalformedGenerics(MalformedGenerics::MissingType))
2306 fn strip_generics_from_path_segment(
2308 ) -> Result<String, ResolutionFailure<'static>> {
2309 let mut stripped_segment = String::new();
2310 let mut param_depth = 0;
2312 let mut latest_generics_chunk = String::new();
2317 latest_generics_chunk.clear();
2318 } else if c == '>' {
2320 if latest_generics_chunk.contains(" as ") {
2321 // The segment tries to use fully-qualified syntax, which is currently unsupported.
2322 // Give a helpful error message instead of completely ignoring the angle brackets.
2323 return Err(ResolutionFailure::MalformedGenerics(
2324 MalformedGenerics::HasFullyQualifiedSyntax,
2328 if param_depth == 0 {
2329 stripped_segment.push(c);
2331 latest_generics_chunk.push(c);
2336 if param_depth == 0 {
2337 Ok(stripped_segment)
2339 // The segment has unbalanced angle brackets, e.g. `Vec<T` or `Vec<T>>`
2340 Err(ResolutionFailure::MalformedGenerics(MalformedGenerics::UnbalancedAngleBrackets))