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, 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::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::fold::DocFolder;
36 use crate::html::markdown::{markdown_links, MarkdownLink};
37 use crate::lint::{BROKEN_INTRA_DOC_LINKS, PRIVATE_INTRA_DOC_LINKS};
38 use crate::passes::Pass;
40 use super::span_of_attrs;
42 crate const COLLECT_INTRA_DOC_LINKS: Pass = Pass {
43 name: "collect-intra-doc-links",
44 run: collect_intra_doc_links,
45 description: "resolves intra-doc links",
48 crate fn collect_intra_doc_links(krate: Crate, cx: &mut DocContext<'_>) -> Crate {
52 kind_side_channel: Cell::new(None),
53 visited_links: FxHashMap::default(),
58 /// Top-level errors emitted by this pass.
60 Resolve(Box<ResolutionFailure<'a>>),
61 AnchorFailure(AnchorFailure),
64 impl<'a> From<ResolutionFailure<'a>> for ErrorKind<'a> {
65 fn from(err: ResolutionFailure<'a>) -> Self {
66 ErrorKind::Resolve(box err)
70 #[derive(Copy, Clone, Debug, Hash)]
73 Primitive(PrimitiveType),
76 type ResolveRes = rustc_hir::def::Res<rustc_ast::NodeId>;
79 fn descr(self) -> &'static str {
81 Res::Def(kind, id) => ResolveRes::Def(kind, id).descr(),
82 Res::Primitive(_) => "builtin type",
86 fn article(self) -> &'static str {
88 Res::Def(kind, id) => ResolveRes::Def(kind, id).article(),
89 Res::Primitive(_) => "a",
93 fn name(self, tcx: TyCtxt<'_>) -> String {
95 Res::Def(_, id) => tcx.item_name(id).to_string(),
96 Res::Primitive(prim) => prim.as_str().to_string(),
100 fn def_id(self) -> DefId {
101 self.opt_def_id().expect("called def_id() on a primitive")
104 fn opt_def_id(self) -> Option<DefId> {
106 Res::Def(_, id) => Some(id),
107 Res::Primitive(_) => None,
111 fn as_hir_res(self) -> Option<rustc_hir::def::Res> {
113 Res::Def(kind, id) => Some(rustc_hir::def::Res::Def(kind, id)),
114 // FIXME: maybe this should handle the subset of PrimitiveType that fits into hir::PrimTy?
115 Res::Primitive(_) => None,
120 impl TryFrom<ResolveRes> for Res {
123 fn try_from(res: ResolveRes) -> Result<Self, ()> {
124 use rustc_hir::def::Res::*;
126 Def(kind, id) => Ok(Res::Def(kind, id)),
127 PrimTy(prim) => Ok(Res::Primitive(PrimitiveType::from_hir(prim))),
129 NonMacroAttr(..) | Err => Result::Err(()),
130 other => bug!("unrecognized res {:?}", other),
135 /// A link failed to resolve.
137 enum ResolutionFailure<'a> {
138 /// This resolved, but with the wrong namespace.
140 /// What the link resolved to.
142 /// The expected namespace for the resolution, determined from the link's disambiguator.
144 /// E.g., for `[fn@Result]` this is [`Namespace::ValueNS`],
145 /// even though `Result`'s actual namespace is [`Namespace::TypeNS`].
146 expected_ns: Namespace,
148 /// The link failed to resolve. [`resolution_failure`] should look to see if there's
149 /// a more helpful error that can be given.
151 /// The scope the link was resolved in.
153 /// If part of the link resolved, this has the `Res`.
155 /// In `[std::io::Error::x]`, `std::io::Error` would be a partial resolution.
156 partial_res: Option<Res>,
157 /// The remaining unresolved path segments.
159 /// In `[std::io::Error::x]`, `x` would be unresolved.
160 unresolved: Cow<'a, str>,
162 /// This happens when rustdoc can't determine the parent scope for an item.
163 /// It is always a bug in rustdoc.
165 /// This link has malformed generic parameters; e.g., the angle brackets are unbalanced.
166 MalformedGenerics(MalformedGenerics),
167 /// Used to communicate that this should be ignored, but shouldn't be reported to the user.
169 /// This happens when there is no disambiguator and one of the namespaces
170 /// failed to resolve.
175 enum MalformedGenerics {
176 /// This link has unbalanced angle brackets.
178 /// For example, `Vec<T` should trigger this, as should `Vec<T>>`.
179 UnbalancedAngleBrackets,
180 /// The generics are not attached to a type.
182 /// For example, `<T>` should trigger this.
184 /// This is detected by checking if the path is empty after the generics are stripped.
186 /// The link uses fully-qualified syntax, which is currently unsupported.
188 /// For example, `<Vec as IntoIterator>::into_iter` should trigger this.
190 /// This is detected by checking if ` as ` (the keyword `as` with spaces around it) is inside
192 HasFullyQualifiedSyntax,
193 /// The link has an invalid path separator.
195 /// For example, `Vec:<T>:new()` should trigger this. Note that `Vec:new()` will **not**
196 /// trigger this because it has no generics and thus [`strip_generics_from_path`] will not be
199 /// Note that this will also **not** be triggered if the invalid path separator is inside angle
200 /// brackets because rustdoc mostly ignores what's inside angle brackets (except for
201 /// [`HasFullyQualifiedSyntax`](MalformedGenerics::HasFullyQualifiedSyntax)).
203 /// This is detected by checking if there is a colon followed by a non-colon in the link.
204 InvalidPathSeparator,
205 /// The link has too many angle brackets.
207 /// For example, `Vec<<T>>` should trigger this.
208 TooManyAngleBrackets,
209 /// The link has empty angle brackets.
211 /// For example, `Vec<>` should trigger this.
215 impl ResolutionFailure<'a> {
216 /// This resolved fully (not just partially) but is erroneous for some other reason
218 /// Returns the full resolution of the link, if present.
219 fn full_res(&self) -> Option<Res> {
221 Self::WrongNamespace { res, expected_ns: _ } => Some(*res),
228 /// User error: `[std#x#y]` is not valid
230 /// The anchor provided by the user conflicts with Rustdoc's generated anchor.
232 /// This is an unfortunate state of affairs. Not every item that can be
233 /// linked to has its own page; sometimes it is a subheading within a page,
234 /// like for associated items. In those cases, rustdoc uses an anchor to
235 /// link to the subheading. Since you can't have two anchors for the same
236 /// link, Rustdoc disallows having a user-specified anchor.
238 /// Most of the time this is fine, because you can just link to the page of
239 /// the item if you want to provide your own anchor. For primitives, though,
240 /// rustdoc uses the anchor as a side channel to know which page to link to;
241 /// it doesn't show up in the generated link. Ideally, rustdoc would remove
242 /// this limitation, allowing you to link to subheaders on primitives.
243 RustdocAnchorConflict(Res),
246 #[derive(Clone, Debug, Hash, PartialEq, Eq)]
247 struct ResolutionInfo {
249 dis: Option<Disambiguator>,
251 extra_fragment: Option<String>,
254 struct DiagnosticInfo<'a> {
258 link_range: Range<usize>,
261 #[derive(Clone, Debug, Hash)]
263 pub res: (Res, Option<String>),
264 pub side_channel: Option<(DefKind, DefId)>,
267 struct LinkCollector<'a, 'tcx> {
268 cx: &'a mut DocContext<'tcx>,
269 /// A stack of modules used to decide what scope to resolve in.
271 /// The last module will be used if the parent scope of the current item is
274 /// This is used to store the kind of associated items,
275 /// because `clean` and the disambiguator code expect them to be different.
276 /// See the code for associated items on inherent impls for details.
277 kind_side_channel: Cell<Option<(DefKind, DefId)>>,
278 /// Cache the resolved links so we can avoid resolving (and emitting errors for) the same link.
279 /// The link will be `None` if it could not be resolved (i.e. the error was cached).
280 visited_links: FxHashMap<ResolutionInfo, Option<CachedLink>>,
283 impl<'a, 'tcx> LinkCollector<'a, 'tcx> {
284 /// Given a full link, parse it as an [enum struct variant].
286 /// In particular, this will return an error whenever there aren't three
287 /// full path segments left in the link.
289 /// [enum struct variant]: hir::VariantData::Struct
292 path_str: &'path str,
294 ) -> Result<(Res, Option<String>), ErrorKind<'path>> {
295 let tcx = self.cx.tcx;
296 let no_res = || ResolutionFailure::NotResolved {
299 unresolved: path_str.into(),
302 debug!("looking for enum variant {}", path_str);
303 let mut split = path_str.rsplitn(3, "::");
304 let (variant_field_str, variant_field_name) = split
306 .map(|f| (f, Symbol::intern(f)))
307 .expect("fold_item should ensure link is non-empty");
308 let (variant_str, variant_name) =
309 // we're not sure this is a variant at all, so use the full string
310 // If there's no second component, the link looks like `[path]`.
311 // So there's no partial res and we should say the whole link failed to resolve.
312 split.next().map(|f| (f, Symbol::intern(f))).ok_or_else(no_res)?;
315 .map(|f| f.to_owned())
316 // If there's no third component, we saw `[a::b]` before and it failed to resolve.
317 // So there's no partial res.
318 .ok_or_else(no_res)?;
321 .enter_resolver(|resolver| {
322 resolver.resolve_str_path_error(DUMMY_SP, &path, TypeNS, module_id)
324 .and_then(|(_, res)| res.try_into())
325 .map_err(|()| no_res())?;
328 Res::Def(DefKind::Enum, did) => {
332 .flat_map(|imp| tcx.associated_items(*imp).in_definition_order())
333 .any(|item| item.ident.name == variant_name)
335 // This is just to let `fold_item` know that this shouldn't be considered;
336 // it's a bug for the error to make it to the user
337 return Err(ResolutionFailure::Dummy.into());
339 match tcx.type_of(did).kind() {
340 ty::Adt(def, _) if def.is_enum() => {
341 if def.all_fields().any(|item| item.ident.name == variant_field_name) {
345 "variant.{}.field.{}",
346 variant_str, variant_field_name
350 Err(ResolutionFailure::NotResolved {
352 partial_res: Some(Res::Def(DefKind::Enum, def.did)),
353 unresolved: variant_field_str.into(),
361 _ => Err(ResolutionFailure::NotResolved {
363 partial_res: Some(ty_res),
364 unresolved: variant_str.into(),
370 /// Given a primitive type, try to resolve an associated item.
372 /// HACK(jynelson): `item_str` is passed in instead of derived from `item_name` so the
373 /// lifetimes on `&'path` will work.
374 fn resolve_primitive_associated_item(
376 prim_ty: PrimitiveType,
380 item_str: &'path str,
381 ) -> Result<(Res, Option<String>), ErrorKind<'path>> {
382 let tcx = self.cx.tcx;
388 tcx.associated_items(impl_)
389 .find_by_name_and_namespace(tcx, Ident::with_dummy_span(item_name), ns, impl_)
391 let kind = item.kind;
392 self.kind_side_channel.set(Some((kind.as_def_kind(), item.def_id)));
394 ty::AssocKind::Fn => "method",
395 ty::AssocKind::Const => "associatedconstant",
396 ty::AssocKind::Type => "associatedtype",
401 Res::Primitive(prim_ty),
402 Some(format!("{}#{}.{}", prim_ty.as_str(), out, item_str)),
408 "returning primitive error for {}::{} in {} namespace",
413 ResolutionFailure::NotResolved {
415 partial_res: Some(Res::Primitive(prim_ty)),
416 unresolved: item_str.into(),
422 /// Resolves a string as a macro.
424 /// FIXME(jynelson): Can this be unified with `resolve()`?
429 ) -> Result<Res, ResolutionFailure<'a>> {
430 let path = ast::Path::from_ident(Ident::from_str(path_str));
431 self.cx.enter_resolver(|resolver| {
432 // FIXME(jynelson): does this really need 3 separate lookups?
433 if let Ok((Some(ext), res)) = resolver.resolve_macro_path(
436 &ParentScope::module(resolver.graph_root(), resolver),
440 if let SyntaxExtensionKind::LegacyBang { .. } = ext.kind {
441 return Ok(res.try_into().unwrap());
444 if let Some(&res) = resolver.all_macros().get(&Symbol::intern(path_str)) {
445 return Ok(res.try_into().unwrap());
447 debug!("resolving {} as a macro in the module {:?}", path_str, module_id);
448 if let Ok((_, res)) =
449 resolver.resolve_str_path_error(DUMMY_SP, path_str, MacroNS, module_id)
451 // don't resolve builtins like `#[derive]`
452 if let Ok(res) = res.try_into() {
456 Err(ResolutionFailure::NotResolved {
459 unresolved: path_str.into(),
464 /// Convenience wrapper around `resolve_str_path_error`.
466 /// This also handles resolving `true` and `false` as booleans.
467 /// NOTE: `resolve_str_path_error` knows only about paths, not about types.
468 /// Associated items will never be resolved by this function.
469 fn resolve_path(&self, path_str: &str, ns: Namespace, module_id: DefId) -> Option<Res> {
470 let result = self.cx.enter_resolver(|resolver| {
472 .resolve_str_path_error(DUMMY_SP, &path_str, ns, module_id)
473 .and_then(|(_, res)| res.try_into())
475 debug!("{} resolved to {:?} in namespace {:?}", path_str, result, ns);
477 // resolver doesn't know about true, false, and types that aren't paths (e.g. `()`)
479 Err(()) => resolve_primitive(path_str, ns),
480 Ok(res) => Some(res),
484 /// Resolves a string as a path within a particular namespace. Returns an
485 /// optional URL fragment in the case of variants and methods.
488 path_str: &'path str,
491 extra_fragment: &Option<String>,
492 ) -> Result<(Res, Option<String>), ErrorKind<'path>> {
493 let tcx = self.cx.tcx;
495 if let Some(res) = self.resolve_path(path_str, ns, module_id) {
497 // FIXME(#76467): make this fallthrough to lookup the associated
498 // item a separate function.
499 Res::Def(DefKind::AssocFn | DefKind::AssocConst, _) => assert_eq!(ns, ValueNS),
500 Res::Def(DefKind::AssocTy, _) => assert_eq!(ns, TypeNS),
501 Res::Def(DefKind::Variant, _) => {
502 return handle_variant(self.cx, res, extra_fragment);
504 // Not a trait item; just return what we found.
505 Res::Primitive(ty) => {
506 if extra_fragment.is_some() {
507 return Err(ErrorKind::AnchorFailure(
508 AnchorFailure::RustdocAnchorConflict(res),
511 return Ok((res, Some(ty.as_str().to_owned())));
513 _ => return Ok((res, extra_fragment.clone())),
517 // Try looking for methods and associated items.
518 let mut split = path_str.rsplitn(2, "::");
519 // NB: `split`'s first element is always defined, even if the delimiter was not present.
520 // NB: `item_str` could be empty when resolving in the root namespace (e.g. `::std`).
521 let item_str = split.next().unwrap();
522 let item_name = Symbol::intern(item_str);
523 let path_root = split
525 .map(|f| f.to_owned())
526 // If there's no `::`, it's not an associated item.
527 // So we can be sure that `rustc_resolve` was accurate when it said it wasn't resolved.
529 debug!("found no `::`, assumming {} was correctly not in scope", item_name);
530 ResolutionFailure::NotResolved {
533 unresolved: item_str.into(),
537 // FIXME: are these both necessary?
538 let ty_res = if let Some(ty_res) = resolve_primitive(&path_root, TypeNS)
539 .or_else(|| self.resolve_path(&path_root, TypeNS, module_id))
543 // FIXME: this is duplicated on the end of this function.
544 return if ns == Namespace::ValueNS {
545 self.variant_field(path_str, module_id)
547 Err(ResolutionFailure::NotResolved {
550 unresolved: path_root.into(),
556 let res = match ty_res {
557 Res::Primitive(prim) => Some(
558 self.resolve_primitive_associated_item(prim, ns, module_id, item_name, item_str),
565 | DefKind::ForeignTy,
568 debug!("looking for associated item named {} for item {:?}", item_name, did);
569 // Checks if item_name belongs to `impl SomeItem`
574 tcx.associated_items(imp).find_by_name_and_namespace(
576 Ident::with_dummy_span(item_name),
581 .map(|item| (item.kind, item.def_id))
582 // There should only ever be one associated item that matches from any inherent impl
584 // Check if item_name belongs to `impl SomeTrait for SomeItem`
585 // FIXME(#74563): This gives precedence to `impl SomeItem`:
586 // Although having both would be ambiguous, use impl version for compatibility's sake.
587 // To handle that properly resolve() would have to support
588 // something like [`ambi_fn`](<SomeStruct as SomeTrait>::ambi_fn)
591 resolve_associated_trait_item(did, module_id, item_name, ns, self.cx);
592 debug!("got associated item kind {:?}", kind);
596 if let Some((kind, id)) = assoc_item {
597 let out = match kind {
598 ty::AssocKind::Fn => "method",
599 ty::AssocKind::Const => "associatedconstant",
600 ty::AssocKind::Type => "associatedtype",
602 Some(if extra_fragment.is_some() {
603 Err(ErrorKind::AnchorFailure(AnchorFailure::RustdocAnchorConflict(ty_res)))
605 // HACK(jynelson): `clean` expects the type, not the associated item
606 // but the disambiguator logic expects the associated item.
607 // Store the kind in a side channel so that only the disambiguator logic looks at it.
608 self.kind_side_channel.set(Some((kind.as_def_kind(), id)));
609 Ok((ty_res, Some(format!("{}.{}", out, item_str))))
611 } else if ns == Namespace::ValueNS {
612 debug!("looking for variants or fields named {} for {:?}", item_name, did);
613 // FIXME(jynelson): why is this different from
615 match tcx.type_of(did).kind() {
617 let field = if def.is_enum() {
618 def.all_fields().find(|item| item.ident.name == item_name)
620 def.non_enum_variant()
623 .find(|item| item.ident.name == item_name)
626 if extra_fragment.is_some() {
635 Err(ErrorKind::AnchorFailure(
636 AnchorFailure::RustdocAnchorConflict(res),
643 if def.is_enum() { "variant" } else { "structfield" },
656 Res::Def(DefKind::Trait, did) => tcx
657 .associated_items(did)
658 .find_by_name_and_namespace(tcx, Ident::with_dummy_span(item_name), ns, did)
660 let kind = match item.kind {
661 ty::AssocKind::Const => "associatedconstant",
662 ty::AssocKind::Type => "associatedtype",
663 ty::AssocKind::Fn => {
664 if item.defaultness.has_value() {
672 if extra_fragment.is_some() {
673 Err(ErrorKind::AnchorFailure(AnchorFailure::RustdocAnchorConflict(ty_res)))
675 let res = Res::Def(item.kind.as_def_kind(), item.def_id);
676 Ok((res, Some(format!("{}.{}", kind, item_str))))
681 res.unwrap_or_else(|| {
682 if ns == Namespace::ValueNS {
683 self.variant_field(path_str, module_id)
685 Err(ResolutionFailure::NotResolved {
687 partial_res: Some(ty_res),
688 unresolved: item_str.into(),
695 /// Used for reporting better errors.
697 /// Returns whether the link resolved 'fully' in another namespace.
698 /// 'fully' here means that all parts of the link resolved, not just some path segments.
699 /// This returns the `Res` even if it was erroneous for some reason
700 /// (such as having invalid URL fragments or being in the wrong namespace).
706 extra_fragment: &Option<String>,
708 // resolve() can't be used for macro namespace
709 let result = match ns {
710 Namespace::MacroNS => self.resolve_macro(path_str, module_id).map_err(ErrorKind::from),
711 Namespace::TypeNS | Namespace::ValueNS => {
712 self.resolve(path_str, ns, module_id, extra_fragment).map(|(res, _)| res)
716 let res = match result {
717 Ok(res) => Some(res),
718 Err(ErrorKind::Resolve(box kind)) => kind.full_res(),
719 Err(ErrorKind::AnchorFailure(AnchorFailure::RustdocAnchorConflict(res))) => Some(res),
720 Err(ErrorKind::AnchorFailure(AnchorFailure::MultipleAnchors)) => None,
722 self.kind_side_channel.take().map(|(kind, id)| Res::Def(kind, id)).or(res)
726 /// Look to see if a resolved item has an associated item named `item_name`.
728 /// Given `[std::io::Error::source]`, where `source` is unresolved, this would
729 /// find `std::error::Error::source` and return
730 /// `<io::Error as error::Error>::source`.
731 fn resolve_associated_trait_item(
736 cx: &mut DocContext<'_>,
737 ) -> Option<(ty::AssocKind, DefId)> {
738 // FIXME: this should also consider blanket impls (`impl<T> X for T`). Unfortunately
739 // `get_auto_trait_and_blanket_impls` is broken because the caching behavior is wrong. In the
740 // meantime, just don't look for these blanket impls.
742 // Next consider explicit impls: `impl MyTrait for MyType`
743 // Give precedence to inherent impls.
744 let traits = traits_implemented_by(cx, did, module);
745 debug!("considering traits {:?}", traits);
746 let mut candidates = traits.iter().filter_map(|&trait_| {
748 .associated_items(trait_)
749 .find_by_name_and_namespace(cx.tcx, Ident::with_dummy_span(item_name), ns, trait_)
750 .map(|assoc| (assoc.kind, assoc.def_id))
752 // FIXME(#74563): warn about ambiguity
753 debug!("the candidates were {:?}", candidates.clone().collect::<Vec<_>>());
757 /// Given a type, return all traits in scope in `module` implemented by that type.
759 /// NOTE: this cannot be a query because more traits could be available when more crates are compiled!
760 /// So it is not stable to serialize cross-crate.
761 fn traits_implemented_by(cx: &mut DocContext<'_>, type_: DefId, module: DefId) -> FxHashSet<DefId> {
762 let mut resolver = cx.resolver.borrow_mut();
763 let in_scope_traits = cx.module_trait_cache.entry(module).or_insert_with(|| {
764 resolver.access(|resolver| {
765 let parent_scope = &ParentScope::module(resolver.get_module(module), resolver);
767 .traits_in_scope(None, parent_scope, SyntaxContext::root(), None)
769 .map(|candidate| candidate.def_id)
775 let ty = tcx.type_of(type_);
776 let iter = in_scope_traits.iter().flat_map(|&trait_| {
777 trace!("considering explicit impl for trait {:?}", trait_);
779 // Look at each trait implementation to see if it's an impl for `did`
780 tcx.find_map_relevant_impl(trait_, ty, |impl_| {
781 let trait_ref = tcx.impl_trait_ref(impl_).expect("this is not an inherent impl");
782 // Check if these are the same type.
783 let impl_type = trait_ref.self_ty();
785 "comparing type {} with kind {:?} against type {:?}",
790 // Fast path: if this is a primitive simple `==` will work
791 let saw_impl = impl_type == ty
792 || match impl_type.kind() {
793 // Check if these are the same def_id
795 debug!("adt def_id: {:?}", def.did);
798 ty::Foreign(def_id) => *def_id == type_,
802 if saw_impl { Some(trait_) } else { None }
808 /// Check for resolve collisions between a trait and its derive.
810 /// These are common and we should just resolve to the trait in that case.
811 fn is_derive_trait_collision<T>(ns: &PerNS<Result<(Res, T), ResolutionFailure<'_>>>) -> bool {
815 type_ns: Ok((Res::Def(DefKind::Trait, _), _)),
816 macro_ns: Ok((Res::Def(DefKind::Macro(MacroKind::Derive), _), _)),
822 impl<'a, 'tcx> DocFolder for LinkCollector<'a, 'tcx> {
823 fn fold_item(&mut self, mut item: Item) -> Option<Item> {
824 use rustc_middle::ty::DefIdTree;
826 let parent_node = if item.is_fake() {
829 find_nearest_parent_module(self.cx.tcx, item.def_id)
832 if parent_node.is_some() {
833 trace!("got parent node for {:?} {:?}, id {:?}", item.type_(), item.name, item.def_id);
836 // find item's parent to resolve `Self` in item's docs below
837 debug!("looking for the `Self` type");
838 let self_id = if item.is_fake() {
840 // Checking if the item is a field in an enum variant
841 } else if (matches!(self.cx.tcx.def_kind(item.def_id), DefKind::Field)
843 self.cx.tcx.def_kind(self.cx.tcx.parent(item.def_id).unwrap()),
847 self.cx.tcx.parent(item.def_id).and_then(|item_id| self.cx.tcx.parent(item_id))
849 self.cx.tcx.def_kind(item.def_id),
856 self.cx.tcx.parent(item.def_id)
857 // HACK(jynelson): `clean` marks associated types as `TypedefItem`, not as `AssocTypeItem`.
858 // Fixing this breaks `fn render_deref_methods`.
859 // As a workaround, see if the parent of the item is an `impl`; if so this must be an associated item,
860 // regardless of what rustdoc wants to call it.
861 } else if let Some(parent) = self.cx.tcx.parent(item.def_id) {
862 let parent_kind = self.cx.tcx.def_kind(parent);
863 Some(if parent_kind == DefKind::Impl { parent } else { item.def_id })
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 if item.is_mod() && item.attrs.inner_docs {
888 self.mod_ids.push(item.def_id);
891 // We want to resolve in the lexical scope of the documentation.
892 // In the presence of re-exports, this is not the same as the module of the item.
893 // Rather than merging all documentation into one, resolve it one attribute at a time
894 // so we know which module it came from.
895 for (parent_module, doc) in item.attrs.collapsed_doc_value_by_module_level() {
896 debug!("combined_docs={}", doc);
898 let (krate, parent_node) = if let Some(id) = parent_module {
901 (item.def_id.krate, parent_node)
903 // NOTE: if there are links that start in one crate and end in another, this will not resolve them.
904 // This is a degenerate case and it's not supported by rustdoc.
905 for md_link in markdown_links(&doc) {
906 let link = self.resolve_link(&item, &doc, &self_name, parent_node, krate, md_link);
907 if let Some(link) = link {
908 item.attrs.links.push(link);
913 Some(if item.is_mod() {
914 if !item.attrs.inner_docs {
915 self.mod_ids.push(item.def_id);
918 let ret = self.fold_item_recur(item);
922 self.fold_item_recur(item)
927 impl LinkCollector<'_, '_> {
928 /// This is the entry point for resolving an intra-doc link.
930 /// FIXME(jynelson): this is way too many arguments
935 self_name: &Option<String>,
936 parent_node: Option<DefId>,
938 ori_link: MarkdownLink,
939 ) -> Option<ItemLink> {
940 trace!("considering link '{}'", ori_link.link);
942 // Bail early for real links.
943 if ori_link.link.contains('/') {
947 // [] is mostly likely not supposed to be a link
948 if ori_link.link.is_empty() {
952 let link = ori_link.link.replace("`", "");
953 let no_backticks_range = range_between_backticks(&ori_link);
954 let parts = link.split('#').collect::<Vec<_>>();
955 let (link, extra_fragment) = if parts.len() > 2 {
956 // A valid link can't have multiple #'s
963 AnchorFailure::MultipleAnchors,
966 } else if parts.len() == 2 {
967 if parts[0].trim().is_empty() {
968 // This is an anchor to an element of the current page, nothing to do in here!
971 (parts[0], Some(parts[1].to_owned()))
976 // Parse and strip the disambiguator from the link, if present.
977 let (mut path_str, disambiguator) = match Disambiguator::from_str(&link) {
978 Ok(Some((d, path))) => (path.trim(), Some(d)),
979 Ok(None) => (link.trim(), None),
980 Err((err_msg, relative_range)) => {
981 let disambiguator_range = (no_backticks_range.start + relative_range.start)
982 ..(no_backticks_range.start + relative_range.end);
983 disambiguator_error(self.cx, &item, dox, disambiguator_range, &err_msg);
988 if path_str.contains(|ch: char| !(ch.is_alphanumeric() || ":_<>, !*&;".contains(ch))) {
992 // We stripped `()` and `!` when parsing the disambiguator.
993 // Add them back to be displayed, but not prefix disambiguators.
995 disambiguator.map(|d| d.display_for(path_str)).unwrap_or_else(|| path_str.to_owned());
997 // In order to correctly resolve intra-doc links we need to
998 // pick a base AST node to work from. If the documentation for
999 // this module came from an inner comment (//!) then we anchor
1000 // our name resolution *inside* the module. If, on the other
1001 // hand it was an outer comment (///) then we anchor the name
1002 // resolution in the parent module on the basis that the names
1003 // used are more likely to be intended to be parent names. For
1004 // this, we set base_node to None for inner comments since
1005 // we've already pushed this node onto the resolution stack but
1006 // for outer comments we explicitly try and resolve against the
1007 // parent_node first.
1008 let base_node = if item.is_mod() && item.attrs.inner_docs {
1009 self.mod_ids.last().copied()
1014 let mut module_id = if let Some(id) = base_node {
1018 debug!("attempting to resolve item without parent module: {}", path_str);
1026 smallvec![ResolutionFailure::NoParentItem],
1032 // replace `Self` with suitable item's parent name
1033 let is_lone_self = path_str == "Self";
1034 let is_lone_crate = path_str == "crate";
1035 if path_str.starts_with("Self::") || is_lone_self {
1036 if let Some(ref name) = self_name {
1040 resolved_self = format!("{}::{}", name, &path_str[6..]);
1041 path_str = &resolved_self;
1044 } else if path_str.starts_with("crate::") || is_lone_crate {
1045 use rustc_span::def_id::CRATE_DEF_INDEX;
1047 // HACK(jynelson): rustc_resolve thinks that `crate` is the crate currently being documented.
1048 // But rustdoc wants it to mean the crate this item was originally present in.
1049 // To work around this, remove it and resolve relative to the crate root instead.
1050 // HACK(jynelson)(2): If we just strip `crate::` then suddenly primitives become ambiguous
1051 // (consider `crate::char`). Instead, change it to `self::`. This works because 'self' is now the crate root.
1052 // FIXME(#78696): This doesn't always work.
1056 resolved_self = format!("self::{}", &path_str["crate::".len()..]);
1057 path_str = &resolved_self;
1059 module_id = DefId { krate, index: CRATE_DEF_INDEX };
1062 // Strip generics from the path.
1063 let stripped_path_string;
1064 if path_str.contains(['<', '>'].as_slice()) {
1065 stripped_path_string = match strip_generics_from_path(path_str) {
1068 debug!("link has malformed generics: {}", path_str);
1076 smallvec![err_kind],
1081 path_str = &stripped_path_string;
1083 // Sanity check to make sure we don't have any angle brackets after stripping generics.
1084 assert!(!path_str.contains(['<', '>'].as_slice()));
1086 // The link is not an intra-doc link if it still contains spaces after stripping generics.
1087 if path_str.contains(' ') {
1091 let diag_info = DiagnosticInfo {
1094 ori_link: &ori_link.link,
1095 link_range: ori_link.range.clone(),
1097 let (mut res, mut fragment) = self.resolve_with_disambiguator_cached(
1101 path_str: path_str.to_owned(),
1105 matches!(ori_link.kind, LinkType::Reference | LinkType::Shortcut),
1108 // Check for a primitive which might conflict with a module
1109 // Report the ambiguity and require that the user specify which one they meant.
1110 // FIXME: could there ever be a primitive not in the type namespace?
1113 None | Some(Disambiguator::Namespace(Namespace::TypeNS) | Disambiguator::Primitive)
1114 ) && !matches!(res, Res::Primitive(_))
1116 if let Some(prim) = resolve_primitive(path_str, TypeNS) {
1118 if matches!(disambiguator, Some(Disambiguator::Primitive)) {
1119 if fragment.is_some() {
1126 AnchorFailure::RustdocAnchorConflict(prim),
1131 fragment = Some(prim.name(self.cx.tcx));
1133 // `[char]` when a `char` module is in scope
1134 let candidates = vec![res, prim];
1135 ambiguity_error(self.cx, &item, path_str, dox, ori_link.range, candidates);
1141 let report_mismatch = |specified: Disambiguator, resolved: Disambiguator| {
1142 // The resolved item did not match the disambiguator; give a better error than 'not found'
1143 let msg = format!("incompatible link kind for `{}`", path_str);
1144 let callback = |diag: &mut DiagnosticBuilder<'_>, sp| {
1146 "this link resolved to {} {}, which is not {} {}",
1149 specified.article(),
1153 suggest_disambiguator(resolved, diag, path_str, dox, sp, &ori_link.range);
1157 BROKEN_INTRA_DOC_LINKS,
1166 let verify = |kind: DefKind, id: DefId| {
1167 let (kind, id) = self.kind_side_channel.take().unwrap_or((kind, id));
1168 debug!("intra-doc link to {} resolved to {:?} (id: {:?})", path_str, res, id);
1170 // Disallow e.g. linking to enums with `struct@`
1171 debug!("saw kind {:?} with disambiguator {:?}", kind, disambiguator);
1172 match (kind, disambiguator) {
1173 | (DefKind::Const | DefKind::ConstParam | DefKind::AssocConst | DefKind::AnonConst, Some(Disambiguator::Kind(DefKind::Const)))
1174 // NOTE: this allows 'method' to mean both normal functions and associated functions
1175 // This can't cause ambiguity because both are in the same namespace.
1176 | (DefKind::Fn | DefKind::AssocFn, Some(Disambiguator::Kind(DefKind::Fn)))
1177 // These are namespaces; allow anything in the namespace to match
1178 | (_, Some(Disambiguator::Namespace(_)))
1179 // If no disambiguator given, allow anything
1181 // All of these are valid, so do nothing
1183 (actual, Some(Disambiguator::Kind(expected))) if actual == expected => {}
1184 (_, Some(specified @ Disambiguator::Kind(_) | specified @ Disambiguator::Primitive)) => {
1185 report_mismatch(specified, Disambiguator::Kind(kind));
1190 // item can be non-local e.g. when using #[doc(primitive = "pointer")]
1191 if let Some((src_id, dst_id)) = id
1193 .and_then(|dst_id| item.def_id.as_local().map(|src_id| (src_id, dst_id)))
1195 use rustc_hir::def_id::LOCAL_CRATE;
1197 let hir_src = self.cx.tcx.hir().local_def_id_to_hir_id(src_id);
1198 let hir_dst = self.cx.tcx.hir().local_def_id_to_hir_id(dst_id);
1200 if self.cx.tcx.privacy_access_levels(LOCAL_CRATE).is_exported(hir_src)
1201 && !self.cx.tcx.privacy_access_levels(LOCAL_CRATE).is_exported(hir_dst)
1203 privacy_error(self.cx, &item, &path_str, dox, &ori_link);
1211 Res::Primitive(prim) => {
1212 if let Some((kind, id)) = self.kind_side_channel.take() {
1213 // We're actually resolving an associated item of a primitive, so we need to
1214 // verify the disambiguator (if any) matches the type of the associated item.
1215 // This case should really follow the same flow as the `Res::Def` branch below,
1216 // but attempting to add a call to `clean::register_res` causes an ICE. @jyn514
1217 // thinks `register_res` is only needed for cross-crate re-exports, but Rust
1218 // doesn't allow statements like `use str::trim;`, making this a (hopefully)
1219 // valid omission. See https://github.com/rust-lang/rust/pull/80660#discussion_r551585677
1220 // for discussion on the matter.
1223 // FIXME: it would be nice to check that the feature gate was enabled in the original crate, not just ignore it altogether.
1224 // However I'm not sure how to check that across crates.
1225 if prim == PrimitiveType::RawPointer
1226 && item.def_id.is_local()
1227 && !self.cx.tcx.features().intra_doc_pointers
1229 let span = super::source_span_for_markdown_range(
1235 .unwrap_or_else(|| span_of_attrs(&item.attrs).unwrap_or(item.span.inner()));
1237 rustc_session::parse::feature_err(
1238 &self.cx.tcx.sess.parse_sess,
1239 sym::intra_doc_pointers,
1241 "linking to associated items of raw pointers is experimental",
1243 .note("rustdoc does not allow disambiguating between `*const` and `*mut`, and pointers are unstable until it does")
1247 match disambiguator {
1248 Some(Disambiguator::Primitive | Disambiguator::Namespace(_)) | None => {}
1250 report_mismatch(other, Disambiguator::Primitive);
1256 Some(ItemLink { link: ori_link.link, link_text, did: None, fragment })
1258 Res::Def(kind, id) => {
1260 let id = clean::register_res(self.cx, rustc_hir::def::Res::Def(kind, id));
1261 Some(ItemLink { link: ori_link.link, link_text, did: Some(id), fragment })
1266 fn resolve_with_disambiguator_cached(
1268 key: ResolutionInfo,
1269 diag: DiagnosticInfo<'_>,
1270 cache_resolution_failure: bool,
1271 ) -> Option<(Res, Option<String>)> {
1272 // Try to look up both the result and the corresponding side channel value
1273 if let Some(ref cached) = self.visited_links.get(&key) {
1276 self.kind_side_channel.set(cached.side_channel.clone());
1277 return Some(cached.res.clone());
1279 None if cache_resolution_failure => return None,
1281 // Although we hit the cache and found a resolution error, this link isn't
1282 // supposed to cache those. Run link resolution again to emit the expected
1283 // resolution error.
1288 let res = self.resolve_with_disambiguator(&key, diag);
1290 // Cache only if resolved successfully - don't silence duplicate errors
1291 if let Some(res) = res {
1292 // Store result for the actual namespace
1293 self.visited_links.insert(
1297 side_channel: self.kind_side_channel.clone().into_inner(),
1303 if cache_resolution_failure {
1304 // For reference-style links we only want to report one resolution error
1305 // so let's cache them as well.
1306 self.visited_links.insert(key, None);
1313 /// After parsing the disambiguator, resolve the main part of the link.
1314 // FIXME(jynelson): wow this is just so much
1315 fn resolve_with_disambiguator(
1317 key: &ResolutionInfo,
1318 diag: DiagnosticInfo<'_>,
1319 ) -> Option<(Res, Option<String>)> {
1320 let disambiguator = key.dis;
1321 let path_str = &key.path_str;
1322 let base_node = key.module_id;
1323 let extra_fragment = &key.extra_fragment;
1325 match disambiguator.map(Disambiguator::ns) {
1326 Some(expected_ns @ (ValueNS | TypeNS)) => {
1327 match self.resolve(path_str, expected_ns, base_node, extra_fragment) {
1328 Ok(res) => Some(res),
1329 Err(ErrorKind::Resolve(box mut kind)) => {
1330 // We only looked in one namespace. Try to give a better error if possible.
1331 if kind.full_res().is_none() {
1332 let other_ns = if expected_ns == ValueNS { TypeNS } else { ValueNS };
1333 // FIXME: really it should be `resolution_failure` that does this, not `resolve_with_disambiguator`
1334 // See https://github.com/rust-lang/rust/pull/76955#discussion_r493953382 for a good approach
1335 for &new_ns in &[other_ns, MacroNS] {
1337 self.check_full_res(new_ns, path_str, base_node, extra_fragment)
1339 kind = ResolutionFailure::WrongNamespace { res, expected_ns };
1353 // This could just be a normal link or a broken link
1354 // we could potentially check if something is
1355 // "intra-doc-link-like" and warn in that case.
1358 Err(ErrorKind::AnchorFailure(msg)) => {
1373 let mut candidates = PerNS {
1375 .resolve_macro(path_str, base_node)
1376 .map(|res| (res, extra_fragment.clone())),
1377 type_ns: match self.resolve(path_str, TypeNS, base_node, extra_fragment) {
1379 debug!("got res in TypeNS: {:?}", res);
1382 Err(ErrorKind::AnchorFailure(msg)) => {
1393 Err(ErrorKind::Resolve(box kind)) => Err(kind),
1395 value_ns: match self.resolve(path_str, ValueNS, base_node, extra_fragment) {
1397 Err(ErrorKind::AnchorFailure(msg)) => {
1408 Err(ErrorKind::Resolve(box kind)) => Err(kind),
1410 .and_then(|(res, fragment)| {
1411 // Constructors are picked up in the type namespace.
1413 Res::Def(DefKind::Ctor(..), _) => {
1414 Err(ResolutionFailure::WrongNamespace { res, expected_ns: TypeNS })
1417 match (fragment, extra_fragment.clone()) {
1418 (Some(fragment), Some(_)) => {
1419 // Shouldn't happen but who knows?
1420 Ok((res, Some(fragment)))
1422 (fragment, None) | (None, fragment) => Ok((res, fragment)),
1429 let len = candidates.iter().filter(|res| res.is_ok()).count();
1439 candidates.into_iter().filter_map(|res| res.err()).collect(),
1441 // this could just be a normal link
1446 Some(candidates.into_iter().filter_map(|res| res.ok()).next().unwrap())
1447 } else if len == 2 && is_derive_trait_collision(&candidates) {
1448 Some(candidates.type_ns.unwrap())
1450 if is_derive_trait_collision(&candidates) {
1451 candidates.macro_ns = Err(ResolutionFailure::Dummy);
1453 // If we're reporting an ambiguity, don't mention the namespaces that failed
1454 let candidates = candidates.map(|candidate| candidate.ok().map(|(res, _)| res));
1461 candidates.present_items().collect(),
1467 match self.resolve_macro(path_str, base_node) {
1468 Ok(res) => Some((res, extra_fragment.clone())),
1470 // `resolve_macro` only looks in the macro namespace. Try to give a better error if possible.
1471 for &ns in &[TypeNS, ValueNS] {
1473 self.check_full_res(ns, path_str, base_node, extra_fragment)
1476 ResolutionFailure::WrongNamespace { res, expected_ns: MacroNS };
1497 /// Get the section of a link between the backticks,
1498 /// or the whole link if there aren't any backticks.
1506 fn range_between_backticks(ori_link: &MarkdownLink) -> Range<usize> {
1507 let after_first_backtick_group = ori_link.link.bytes().position(|b| b != b'`').unwrap_or(0);
1508 let before_second_backtick_group = ori_link
1511 .skip(after_first_backtick_group)
1512 .position(|b| b == b'`')
1513 .unwrap_or(ori_link.link.len());
1514 (ori_link.range.start + after_first_backtick_group)
1515 ..(ori_link.range.start + before_second_backtick_group)
1518 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1519 /// Disambiguators for a link.
1520 crate enum Disambiguator {
1523 /// This is buggy, see <https://github.com/rust-lang/rust/pull/77875#discussion_r503583103>
1525 /// `struct@` or `f()`
1528 Namespace(Namespace),
1531 impl Disambiguator {
1532 /// The text that should be displayed when the path is rendered as HTML.
1534 /// NOTE: `path` is not the original link given by the user, but a name suitable for passing to `resolve`.
1535 fn display_for(&self, path: &str) -> String {
1537 // FIXME: this will have different output if the user had `m!()` originally.
1538 Self::Kind(DefKind::Macro(MacroKind::Bang)) => format!("{}!", path),
1539 Self::Kind(DefKind::Fn) => format!("{}()", path),
1540 _ => path.to_owned(),
1544 /// Given a link, parse and return `(disambiguator, path_str)`.
1546 /// This returns `Ok(Some(...))` if a disambiguator was found,
1547 /// `Ok(None)` if no disambiguator was found, or `Err(...)`
1548 /// if there was a problem with the disambiguator.
1549 crate fn from_str(link: &str) -> Result<Option<(Self, &str)>, (String, Range<usize>)> {
1550 use Disambiguator::{Kind, Namespace as NS, Primitive};
1552 if let Some(idx) = link.find('@') {
1553 let (prefix, rest) = link.split_at(idx);
1554 let d = match prefix {
1555 "struct" => Kind(DefKind::Struct),
1556 "enum" => Kind(DefKind::Enum),
1557 "trait" => Kind(DefKind::Trait),
1558 "union" => Kind(DefKind::Union),
1559 "module" | "mod" => Kind(DefKind::Mod),
1560 "const" | "constant" => Kind(DefKind::Const),
1561 "static" => Kind(DefKind::Static),
1562 "function" | "fn" | "method" => Kind(DefKind::Fn),
1563 "derive" => Kind(DefKind::Macro(MacroKind::Derive)),
1564 "type" => NS(Namespace::TypeNS),
1565 "value" => NS(Namespace::ValueNS),
1566 "macro" => NS(Namespace::MacroNS),
1567 "prim" | "primitive" => Primitive,
1568 _ => return Err((format!("unknown disambiguator `{}`", prefix), 0..idx)),
1570 Ok(Some((d, &rest[1..])))
1573 ("!()", DefKind::Macro(MacroKind::Bang)),
1574 ("()", DefKind::Fn),
1575 ("!", DefKind::Macro(MacroKind::Bang)),
1577 for &(suffix, kind) in &suffixes {
1578 if let Some(link) = link.strip_suffix(suffix) {
1579 // Avoid turning `!` or `()` into an empty string
1580 if !link.is_empty() {
1581 return Ok(Some((Kind(kind), link)));
1589 fn from_res(res: Res) -> Self {
1591 Res::Def(kind, _) => Disambiguator::Kind(kind),
1592 Res::Primitive(_) => Disambiguator::Primitive,
1596 /// Used for error reporting.
1597 fn suggestion(self) -> Suggestion {
1598 let kind = match self {
1599 Disambiguator::Primitive => return Suggestion::Prefix("prim"),
1600 Disambiguator::Kind(kind) => kind,
1601 Disambiguator::Namespace(_) => panic!("display_for cannot be used on namespaces"),
1603 if kind == DefKind::Macro(MacroKind::Bang) {
1604 return Suggestion::Macro;
1605 } else if kind == DefKind::Fn || kind == DefKind::AssocFn {
1606 return Suggestion::Function;
1609 let prefix = match kind {
1610 DefKind::Struct => "struct",
1611 DefKind::Enum => "enum",
1612 DefKind::Trait => "trait",
1613 DefKind::Union => "union",
1614 DefKind::Mod => "mod",
1615 DefKind::Const | DefKind::ConstParam | DefKind::AssocConst | DefKind::AnonConst => {
1618 DefKind::Static => "static",
1619 DefKind::Macro(MacroKind::Derive) => "derive",
1620 // Now handle things that don't have a specific disambiguator
1623 .expect("tried to calculate a disambiguator for a def without a namespace?")
1625 Namespace::TypeNS => "type",
1626 Namespace::ValueNS => "value",
1627 Namespace::MacroNS => "macro",
1631 Suggestion::Prefix(prefix)
1634 fn ns(self) -> Namespace {
1636 Self::Namespace(n) => n,
1638 k.ns().expect("only DefKinds with a valid namespace can be disambiguators")
1640 Self::Primitive => TypeNS,
1644 fn article(self) -> &'static str {
1646 Self::Namespace(_) => panic!("article() doesn't make sense for namespaces"),
1647 Self::Kind(k) => k.article(),
1648 Self::Primitive => "a",
1652 fn descr(self) -> &'static str {
1654 Self::Namespace(n) => n.descr(),
1655 // HACK(jynelson): by looking at the source I saw the DefId we pass
1656 // for `expected.descr()` doesn't matter, since it's not a crate
1657 Self::Kind(k) => k.descr(DefId::local(hir::def_id::DefIndex::from_usize(0))),
1658 Self::Primitive => "builtin type",
1663 /// A suggestion to show in a diagnostic.
1666 Prefix(&'static str),
1674 fn descr(&self) -> Cow<'static, str> {
1676 Self::Prefix(x) => format!("prefix with `{}@`", x).into(),
1677 Self::Function => "add parentheses".into(),
1678 Self::Macro => "add an exclamation mark".into(),
1682 fn as_help(&self, path_str: &str) -> String {
1683 // FIXME: if this is an implied shortcut link, it's bad style to suggest `@`
1685 Self::Prefix(prefix) => format!("{}@{}", prefix, path_str),
1686 Self::Function => format!("{}()", path_str),
1687 Self::Macro => format!("{}!", path_str),
1692 /// Reports a diagnostic for an intra-doc link.
1694 /// If no link range is provided, or the source span of the link cannot be determined, the span of
1695 /// the entire documentation block is used for the lint. If a range is provided but the span
1696 /// calculation fails, a note is added to the diagnostic pointing to the link in the markdown.
1698 /// The `decorate` callback is invoked in all cases to allow further customization of the
1699 /// diagnostic before emission. If the span of the link was able to be determined, the second
1700 /// parameter of the callback will contain it, and the primary span of the diagnostic will be set
1702 fn report_diagnostic(
1704 lint: &'static Lint,
1708 link_range: &Range<usize>,
1709 decorate: impl FnOnce(&mut DiagnosticBuilder<'_>, Option<rustc_span::Span>),
1711 let hir_id = match DocContext::as_local_hir_id(tcx, item.def_id) {
1712 Some(hir_id) => hir_id,
1714 // If non-local, no need to check anything.
1715 info!("ignoring warning from parent crate: {}", msg);
1720 let attrs = &item.attrs;
1721 let sp = span_of_attrs(attrs).unwrap_or(item.span.inner());
1723 tcx.struct_span_lint_hir(lint, hir_id, sp, |lint| {
1724 let mut diag = lint.build(msg);
1726 let span = super::source_span_for_markdown_range(tcx, dox, link_range, attrs);
1728 if let Some(sp) = span {
1731 // blah blah blah\nblah\nblah [blah] blah blah\nblah blah
1734 // last_new_line_offset
1735 let last_new_line_offset = dox[..link_range.start].rfind('\n').map_or(0, |n| n + 1);
1736 let line = dox[last_new_line_offset..].lines().next().unwrap_or("");
1738 // Print the line containing the `link_range` and manually mark it with '^'s.
1740 "the link appears in this line:\n\n{line}\n\
1741 {indicator: <before$}{indicator:^<found$}",
1744 before = link_range.start - last_new_line_offset,
1745 found = link_range.len(),
1749 decorate(&mut diag, span);
1755 /// Reports a link that failed to resolve.
1757 /// This also tries to resolve any intermediate path segments that weren't
1758 /// handled earlier. For example, if passed `Item::Crate(std)` and `path_str`
1759 /// `std::io::Error::x`, this will resolve `std::io::Error`.
1760 fn resolution_failure(
1761 collector: &mut LinkCollector<'_, '_>,
1764 disambiguator: Option<Disambiguator>,
1766 link_range: Range<usize>,
1767 kinds: SmallVec<[ResolutionFailure<'_>; 3]>,
1769 let tcx = collector.cx.tcx;
1772 BROKEN_INTRA_DOC_LINKS,
1773 &format!("unresolved link to `{}`", path_str),
1778 let item = |res: Res| format!("the {} `{}`", res.descr(), res.name(tcx),);
1779 let assoc_item_not_allowed = |res: Res| {
1780 let name = res.name(tcx);
1782 "`{}` is {} {}, not a module or type, and cannot have associated items",
1788 // ignore duplicates
1789 let mut variants_seen = SmallVec::<[_; 3]>::new();
1790 for mut failure in kinds {
1791 let variant = std::mem::discriminant(&failure);
1792 if variants_seen.contains(&variant) {
1795 variants_seen.push(variant);
1797 if let ResolutionFailure::NotResolved { module_id, partial_res, unresolved } =
1802 let module_id = *module_id;
1803 // FIXME(jynelson): this might conflict with my `Self` fix in #76467
1804 // FIXME: maybe use itertools `collect_tuple` instead?
1805 fn split(path: &str) -> Option<(&str, &str)> {
1806 let mut splitter = path.rsplitn(2, "::");
1807 splitter.next().and_then(|right| splitter.next().map(|left| (left, right)))
1810 // Check if _any_ parent of the path gets resolved.
1811 // If so, report it and say the first which failed; if not, say the first path segment didn't resolve.
1812 let mut name = path_str;
1814 let (start, end) = if let Some(x) = split(name) {
1817 // avoid bug that marked [Quux::Z] as missing Z, not Quux
1818 if partial_res.is_none() {
1819 *unresolved = name.into();
1824 for &ns in &[TypeNS, ValueNS, MacroNS] {
1826 collector.check_full_res(ns, &start, module_id, &None)
1828 debug!("found partial_res={:?}", res);
1829 *partial_res = Some(res);
1830 *unresolved = end.into();
1834 *unresolved = end.into();
1837 let last_found_module = match *partial_res {
1838 Some(Res::Def(DefKind::Mod, id)) => Some(id),
1839 None => Some(module_id),
1842 // See if this was a module: `[path]` or `[std::io::nope]`
1843 if let Some(module) = last_found_module {
1844 let note = if partial_res.is_some() {
1845 // Part of the link resolved; e.g. `std::io::nonexistent`
1846 let module_name = tcx.item_name(module);
1847 format!("no item named `{}` in module `{}`", unresolved, module_name)
1849 // None of the link resolved; e.g. `Notimported`
1850 format!("no item named `{}` in scope", unresolved)
1852 if let Some(span) = sp {
1853 diag.span_label(span, ¬e);
1858 // If the link has `::` in it, assume it was meant to be an intra-doc link.
1859 // Otherwise, the `[]` might be unrelated.
1860 // FIXME: don't show this for autolinks (`<>`), `()` style links, or reference links
1861 if !path_str.contains("::") {
1862 diag.help(r#"to escape `[` and `]` characters, add '\' before them like `\[` or `\]`"#);
1868 // Otherwise, it must be an associated item or variant
1869 let res = partial_res.expect("None case was handled by `last_found_module`");
1870 let name = res.name(tcx);
1871 let kind = match res {
1872 Res::Def(kind, _) => Some(kind),
1873 Res::Primitive(_) => None,
1875 let path_description = if let Some(kind) = kind {
1877 Mod | ForeignMod => "inner item",
1878 Struct => "field or associated item",
1879 Enum | Union => "variant or associated item",
1896 let note = assoc_item_not_allowed(res);
1897 if let Some(span) = sp {
1898 diag.span_label(span, ¬e);
1904 Trait | TyAlias | ForeignTy | OpaqueTy | TraitAlias | TyParam
1905 | Static => "associated item",
1906 Impl | GlobalAsm => unreachable!("not a path"),
1912 "the {} `{}` has no {} named `{}`",
1915 disambiguator.map_or(path_description, |d| d.descr()),
1918 if let Some(span) = sp {
1919 diag.span_label(span, ¬e);
1926 let note = match failure {
1927 ResolutionFailure::NotResolved { .. } => unreachable!("handled above"),
1928 ResolutionFailure::Dummy => continue,
1929 ResolutionFailure::WrongNamespace { res, expected_ns } => {
1930 if let Res::Def(kind, _) = res {
1931 let disambiguator = Disambiguator::Kind(kind);
1932 suggest_disambiguator(
1943 "this link resolves to {}, which is not in the {} namespace",
1948 ResolutionFailure::NoParentItem => {
1949 diag.level = rustc_errors::Level::Bug;
1950 "all intra-doc links should have a parent item".to_owned()
1952 ResolutionFailure::MalformedGenerics(variant) => match variant {
1953 MalformedGenerics::UnbalancedAngleBrackets => {
1954 String::from("unbalanced angle brackets")
1956 MalformedGenerics::MissingType => {
1957 String::from("missing type for generic parameters")
1959 MalformedGenerics::HasFullyQualifiedSyntax => {
1960 diag.note("see https://github.com/rust-lang/rust/issues/74563 for more information");
1961 String::from("fully-qualified syntax is unsupported")
1963 MalformedGenerics::InvalidPathSeparator => {
1964 String::from("has invalid path separator")
1966 MalformedGenerics::TooManyAngleBrackets => {
1967 String::from("too many angle brackets")
1969 MalformedGenerics::EmptyAngleBrackets => {
1970 String::from("empty angle brackets")
1974 if let Some(span) = sp {
1975 diag.span_label(span, ¬e);
1984 /// Report an anchor failure.
1986 cx: &DocContext<'_>,
1990 link_range: Range<usize>,
1991 failure: AnchorFailure,
1993 let msg = match failure {
1994 AnchorFailure::MultipleAnchors => format!("`{}` contains multiple anchors", path_str),
1995 AnchorFailure::RustdocAnchorConflict(res) => format!(
1996 "`{}` contains an anchor, but links to {kind}s are already anchored",
2002 report_diagnostic(cx.tcx, BROKEN_INTRA_DOC_LINKS, &msg, item, dox, &link_range, |diag, sp| {
2003 if let Some(sp) = sp {
2004 diag.span_label(sp, "contains invalid anchor");
2009 /// Report an error in the link disambiguator.
2010 fn disambiguator_error(
2011 cx: &DocContext<'_>,
2014 link_range: Range<usize>,
2017 report_diagnostic(cx.tcx, BROKEN_INTRA_DOC_LINKS, msg, item, dox, &link_range, |_diag, _sp| {});
2020 /// Report an ambiguity error, where there were multiple possible resolutions.
2022 cx: &DocContext<'_>,
2026 link_range: Range<usize>,
2027 candidates: Vec<Res>,
2029 let mut msg = format!("`{}` is ", path_str);
2031 match candidates.as_slice() {
2032 [first_def, second_def] => {
2034 "both {} {} and {} {}",
2035 first_def.article(),
2037 second_def.article(),
2042 let mut candidates = candidates.iter().peekable();
2043 while let Some(res) = candidates.next() {
2044 if candidates.peek().is_some() {
2045 msg += &format!("{} {}, ", res.article(), res.descr());
2047 msg += &format!("and {} {}", res.article(), res.descr());
2053 report_diagnostic(cx.tcx, BROKEN_INTRA_DOC_LINKS, &msg, item, dox, &link_range, |diag, sp| {
2054 if let Some(sp) = sp {
2055 diag.span_label(sp, "ambiguous link");
2057 diag.note("ambiguous link");
2060 for res in candidates {
2061 let disambiguator = Disambiguator::from_res(res);
2062 suggest_disambiguator(disambiguator, diag, path_str, dox, sp, &link_range);
2067 /// In case of an ambiguity or mismatched disambiguator, suggest the correct
2069 fn suggest_disambiguator(
2070 disambiguator: Disambiguator,
2071 diag: &mut DiagnosticBuilder<'_>,
2074 sp: Option<rustc_span::Span>,
2075 link_range: &Range<usize>,
2077 let suggestion = disambiguator.suggestion();
2078 let help = format!("to link to the {}, {}", disambiguator.descr(), suggestion.descr());
2080 if let Some(sp) = sp {
2081 let msg = if dox.bytes().nth(link_range.start) == Some(b'`') {
2082 format!("`{}`", suggestion.as_help(path_str))
2084 suggestion.as_help(path_str)
2087 diag.span_suggestion(sp, &help, msg, Applicability::MaybeIncorrect);
2089 diag.help(&format!("{}: {}", help, suggestion.as_help(path_str)));
2093 /// Report a link from a public item to a private one.
2094 fn privacy_error(cx: &DocContext<'_>, item: &Item, path_str: &str, dox: &str, link: &MarkdownLink) {
2096 let item_name = match item.name {
2098 sym = name.as_str();
2101 None => "<unknown>",
2104 format!("public documentation for `{}` links to private item `{}`", item_name, path_str);
2106 report_diagnostic(cx.tcx, PRIVATE_INTRA_DOC_LINKS, &msg, item, dox, &link.range, |diag, sp| {
2107 if let Some(sp) = sp {
2108 diag.span_label(sp, "this item is private");
2111 let note_msg = if cx.render_options.document_private {
2112 "this link resolves only because you passed `--document-private-items`, but will break without"
2114 "this link will resolve properly if you pass `--document-private-items`"
2116 diag.note(note_msg);
2120 /// Given an enum variant's res, return the res of its enum and the associated fragment.
2122 cx: &DocContext<'_>,
2124 extra_fragment: &Option<String>,
2125 ) -> Result<(Res, Option<String>), ErrorKind<'static>> {
2126 use rustc_middle::ty::DefIdTree;
2128 if extra_fragment.is_some() {
2129 return Err(ErrorKind::AnchorFailure(AnchorFailure::RustdocAnchorConflict(res)));
2132 .parent(res.def_id())
2134 let parent_def = Res::Def(DefKind::Enum, parent);
2135 let variant = cx.tcx.expect_variant_res(res.as_hir_res().unwrap());
2136 (parent_def, Some(format!("variant.{}", variant.ident.name)))
2138 .ok_or_else(|| ResolutionFailure::NoParentItem.into())
2141 /// Resolve a primitive type or value.
2142 fn resolve_primitive(path_str: &str, ns: Namespace) -> Option<Res> {
2146 use PrimitiveType::*;
2147 let prim = match path_str {
2163 "bool" | "true" | "false" => Bool,
2164 "str" | "&str" => Str,
2165 // See #80181 for why these don't have symbols associated.
2170 "pointer" | "*const" | "*mut" => RawPointer,
2171 "reference" | "&" | "&mut" => Reference,
2173 "never" | "!" => Never,
2176 debug!("resolved primitives {:?}", prim);
2177 Some(Res::Primitive(prim))
2180 fn strip_generics_from_path(path_str: &str) -> Result<String, ResolutionFailure<'static>> {
2181 let mut stripped_segments = vec![];
2182 let mut path = path_str.chars().peekable();
2183 let mut segment = Vec::new();
2185 while let Some(chr) = path.next() {
2188 if path.next_if_eq(&':').is_some() {
2189 let stripped_segment =
2190 strip_generics_from_path_segment(mem::take(&mut segment))?;
2191 if !stripped_segment.is_empty() {
2192 stripped_segments.push(stripped_segment);
2195 return Err(ResolutionFailure::MalformedGenerics(
2196 MalformedGenerics::InvalidPathSeparator,
2205 return Err(ResolutionFailure::MalformedGenerics(
2206 MalformedGenerics::TooManyAngleBrackets,
2210 return Err(ResolutionFailure::MalformedGenerics(
2211 MalformedGenerics::EmptyAngleBrackets,
2217 while let Some(chr) = path.next_if(|c| *c != '>') {
2224 _ => segment.push(chr),
2226 trace!("raw segment: {:?}", segment);
2229 if !segment.is_empty() {
2230 let stripped_segment = strip_generics_from_path_segment(segment)?;
2231 if !stripped_segment.is_empty() {
2232 stripped_segments.push(stripped_segment);
2236 debug!("path_str: {:?}\nstripped segments: {:?}", path_str, &stripped_segments);
2238 let stripped_path = stripped_segments.join("::");
2240 if !stripped_path.is_empty() {
2243 Err(ResolutionFailure::MalformedGenerics(MalformedGenerics::MissingType))
2247 fn strip_generics_from_path_segment(
2249 ) -> Result<String, ResolutionFailure<'static>> {
2250 let mut stripped_segment = String::new();
2251 let mut param_depth = 0;
2253 let mut latest_generics_chunk = String::new();
2258 latest_generics_chunk.clear();
2259 } else if c == '>' {
2261 if latest_generics_chunk.contains(" as ") {
2262 // The segment tries to use fully-qualified syntax, which is currently unsupported.
2263 // Give a helpful error message instead of completely ignoring the angle brackets.
2264 return Err(ResolutionFailure::MalformedGenerics(
2265 MalformedGenerics::HasFullyQualifiedSyntax,
2269 if param_depth == 0 {
2270 stripped_segment.push(c);
2272 latest_generics_chunk.push(c);
2277 if param_depth == 0 {
2278 Ok(stripped_segment)
2280 // The segment has unbalanced angle brackets, e.g. `Vec<T` or `Vec<T>>`
2281 Err(ResolutionFailure::MalformedGenerics(MalformedGenerics::UnbalancedAngleBrackets))