1 //! Support for inlining external documentation into the current AST.
7 use rustc_data_structures::fx::FxHashSet;
9 use rustc_hir::def::{DefKind, Res};
10 use rustc_hir::def_id::DefId;
11 use rustc_hir::Mutability;
12 use rustc_metadata::creader::{CStore, LoadedMacro};
13 use rustc_middle::ty::{self, TyCtxt};
14 use rustc_span::hygiene::MacroKind;
15 use rustc_span::symbol::{kw, sym, Symbol};
18 self, utils, Attributes, AttributesExt, GetDefId, ItemId, NestedAttributesExt, Type,
20 use crate::core::DocContext;
21 use crate::formats::item_type::ItemType;
23 use super::{Clean, Visibility};
25 type Attrs<'hir> = rustc_middle::ty::Attributes<'hir>;
27 /// Attempt to inline a definition into this AST.
29 /// This function will fetch the definition specified, and if it is
30 /// from another crate it will attempt to inline the documentation
31 /// from the other crate into this crate.
33 /// This is primarily used for `pub use` statements which are, in general,
34 /// implementation details. Inlining the documentation should help provide a
35 /// better experience when reading the documentation in this use case.
37 /// The returned value is `None` if the definition could not be inlined,
38 /// and `Some` of a vector of items if it was successfully expanded.
40 /// `parent_module` refers to the parent of the *re-export*, not the original item.
42 cx: &mut DocContext<'_>,
44 import_def_id: Option<DefId>,
47 attrs: Option<Attrs<'_>>,
48 visited: &mut FxHashSet<DefId>,
49 ) -> Option<Vec<clean::Item>> {
50 let did = res.opt_def_id()?;
54 let mut ret = Vec::new();
56 debug!("attrs={:?}", attrs);
57 let attrs_clone = attrs;
59 let kind = match res {
60 Res::Def(DefKind::Trait, did) => {
61 record_extern_fqn(cx, did, ItemType::Trait);
62 build_impls(cx, Some(parent_module), did, attrs, &mut ret);
63 clean::TraitItem(build_external_trait(cx, did))
65 Res::Def(DefKind::Fn, did) => {
66 record_extern_fqn(cx, did, ItemType::Function);
67 clean::FunctionItem(build_external_function(cx, did))
69 Res::Def(DefKind::Struct, did) => {
70 record_extern_fqn(cx, did, ItemType::Struct);
71 build_impls(cx, Some(parent_module), did, attrs, &mut ret);
72 clean::StructItem(build_struct(cx, did))
74 Res::Def(DefKind::Union, did) => {
75 record_extern_fqn(cx, did, ItemType::Union);
76 build_impls(cx, Some(parent_module), did, attrs, &mut ret);
77 clean::UnionItem(build_union(cx, did))
79 Res::Def(DefKind::TyAlias, did) => {
80 record_extern_fqn(cx, did, ItemType::Typedef);
81 build_impls(cx, Some(parent_module), did, attrs, &mut ret);
82 clean::TypedefItem(build_type_alias(cx, did), false)
84 Res::Def(DefKind::Enum, did) => {
85 record_extern_fqn(cx, did, ItemType::Enum);
86 build_impls(cx, Some(parent_module), did, attrs, &mut ret);
87 clean::EnumItem(build_enum(cx, did))
89 Res::Def(DefKind::ForeignTy, did) => {
90 record_extern_fqn(cx, did, ItemType::ForeignType);
91 build_impls(cx, Some(parent_module), did, attrs, &mut ret);
92 clean::ForeignTypeItem
94 // Never inline enum variants but leave them shown as re-exports.
95 Res::Def(DefKind::Variant, _) => return None,
96 // Assume that enum variants and struct types are re-exported next to
97 // their constructors.
98 Res::Def(DefKind::Ctor(..), _) | Res::SelfCtor(..) => return Some(Vec::new()),
99 Res::Def(DefKind::Mod, did) => {
100 record_extern_fqn(cx, did, ItemType::Module);
101 clean::ModuleItem(build_module(cx, did, visited))
103 Res::Def(DefKind::Static, did) => {
104 record_extern_fqn(cx, did, ItemType::Static);
105 clean::StaticItem(build_static(cx, did, cx.tcx.is_mutable_static(did)))
107 Res::Def(DefKind::Const, did) => {
108 record_extern_fqn(cx, did, ItemType::Constant);
109 clean::ConstantItem(build_const(cx, did))
111 Res::Def(DefKind::Macro(kind), did) => {
112 let mac = build_macro(cx, did, name, import_def_id);
114 let type_kind = match kind {
115 MacroKind::Bang => ItemType::Macro,
116 MacroKind::Attr => ItemType::ProcAttribute,
117 MacroKind::Derive => ItemType::ProcDerive,
119 record_extern_fqn(cx, did, type_kind);
125 let (attrs, cfg) = merge_attrs(cx, Some(parent_module), load_attrs(cx, did), attrs_clone);
126 cx.inlined.insert(did.into());
128 clean::Item::from_def_id_and_attrs_and_parts(did, Some(name), kind, box attrs, cx, cfg);
129 if let Some(import_def_id) = import_def_id {
130 // The visibility needs to reflect the one from the reexport and not from the "source" DefId.
131 item.visibility = cx.tcx.visibility(import_def_id).clean(cx);
137 crate fn try_inline_glob(
138 cx: &mut DocContext<'_>,
140 visited: &mut FxHashSet<DefId>,
141 ) -> Option<Vec<clean::Item>> {
142 let did = res.opt_def_id()?;
148 Res::Def(DefKind::Mod, did) => {
149 let m = build_module(cx, did, visited);
152 // glob imports on things like enums aren't inlined even for local exports, so just bail
157 crate fn load_attrs<'hir>(cx: &DocContext<'hir>, did: DefId) -> Attrs<'hir> {
158 cx.tcx.get_attrs(did)
161 /// Record an external fully qualified name in the external_paths cache.
163 /// These names are used later on by HTML rendering to generate things like
164 /// source links back to the original item.
165 crate fn record_extern_fqn(cx: &mut DocContext<'_>, did: DefId, kind: ItemType) {
166 let crate_name = cx.tcx.crate_name(did.krate).to_string();
168 let relative = cx.tcx.def_path(did).data.into_iter().filter_map(|elem| {
169 // extern blocks have an empty name
170 let s = elem.data.to_string();
171 if !s.is_empty() { Some(s) } else { None }
173 let fqn = if let ItemType::Macro = kind {
174 // Check to see if it is a macro 2.0 or built-in macro
176 CStore::from_tcx(cx.tcx).load_macro_untracked(did, cx.sess()),
177 LoadedMacro::MacroDef(def, _)
178 if matches!(&def.kind, ast::ItemKind::MacroDef(ast_def)
179 if !ast_def.macro_rules)
181 once(crate_name).chain(relative).collect()
183 vec![crate_name, relative.last().expect("relative was empty")]
186 once(crate_name).chain(relative).collect()
190 cx.cache.exact_paths.insert(did, fqn);
192 cx.cache.external_paths.insert(did, (fqn, kind));
196 crate fn build_external_trait(cx: &mut DocContext<'_>, did: DefId) -> clean::Trait {
199 .associated_items(did)
200 .in_definition_order()
202 // When building an external trait, the cleaned trait will have all items public,
203 // which causes methods to have a `pub` prefix, which is invalid since items in traits
204 // can not have a visibility prefix. Thus we override the visibility here manually.
205 // See https://github.com/rust-lang/rust/issues/81274
206 clean::Item { visibility: Visibility::Inherited, ..item.clean(cx) }
210 let predicates = cx.tcx.predicates_of(did);
211 let generics = (cx.tcx.generics_of(did), predicates).clean(cx);
212 let generics = filter_non_trait_generics(did, generics);
213 let (generics, supertrait_bounds) = separate_supertrait_bounds(generics);
214 let is_auto = cx.tcx.trait_is_auto(did);
216 unsafety: cx.tcx.trait_def(did).unsafety,
219 bounds: supertrait_bounds,
224 fn build_external_function(cx: &mut DocContext<'_>, did: DefId) -> clean::Function {
225 let sig = cx.tcx.fn_sig(did);
228 if cx.tcx.is_const_fn_raw(did) { hir::Constness::Const } else { hir::Constness::NotConst };
229 let asyncness = cx.tcx.asyncness(did);
230 let predicates = cx.tcx.predicates_of(did);
231 let (generics, decl) = clean::enter_impl_trait(cx, |cx| {
232 ((cx.tcx.generics_of(did), predicates).clean(cx), (did, sig).clean(cx))
237 header: hir::FnHeader { unsafety: sig.unsafety(), abi: sig.abi(), constness, asyncness },
241 fn build_enum(cx: &mut DocContext<'_>, did: DefId) -> clean::Enum {
242 let predicates = cx.tcx.explicit_predicates_of(did);
245 generics: (cx.tcx.generics_of(did), predicates).clean(cx),
246 variants_stripped: false,
247 variants: cx.tcx.adt_def(did).variants.clean(cx),
251 fn build_struct(cx: &mut DocContext<'_>, did: DefId) -> clean::Struct {
252 let predicates = cx.tcx.explicit_predicates_of(did);
253 let variant = cx.tcx.adt_def(did).non_enum_variant();
256 struct_type: variant.ctor_kind,
257 generics: (cx.tcx.generics_of(did), predicates).clean(cx),
258 fields: variant.fields.clean(cx),
259 fields_stripped: false,
263 fn build_union(cx: &mut DocContext<'_>, did: DefId) -> clean::Union {
264 let predicates = cx.tcx.explicit_predicates_of(did);
265 let variant = cx.tcx.adt_def(did).non_enum_variant();
268 generics: (cx.tcx.generics_of(did), predicates).clean(cx),
269 fields: variant.fields.clean(cx),
270 fields_stripped: false,
274 fn build_type_alias(cx: &mut DocContext<'_>, did: DefId) -> clean::Typedef {
275 let predicates = cx.tcx.explicit_predicates_of(did);
276 let type_ = cx.tcx.type_of(did).clean(cx);
280 generics: (cx.tcx.generics_of(did), predicates).clean(cx),
285 /// Builds all inherent implementations of an ADT (struct/union/enum) or Trait item/path/reexport.
286 crate fn build_impls(
287 cx: &mut DocContext<'_>,
288 parent_module: Option<DefId>,
290 attrs: Option<Attrs<'_>>,
291 ret: &mut Vec<clean::Item>,
295 // for each implementation of an item represented by `did`, build the clean::Item for that impl
296 for &did in tcx.inherent_impls(did).iter() {
297 build_impl(cx, parent_module, did, attrs, ret);
301 /// `parent_module` refers to the parent of the re-export, not the original item
303 cx: &mut DocContext<'_>,
304 parent_module: Option<DefId>,
305 old_attrs: Attrs<'_>,
306 new_attrs: Option<Attrs<'_>>,
307 ) -> (clean::Attributes, Option<Arc<clean::cfg::Cfg>>) {
308 // NOTE: If we have additional attributes (from a re-export),
309 // always insert them first. This ensure that re-export
310 // doc comments show up before the original doc comments
311 // when we render them.
312 if let Some(inner) = new_attrs {
313 let mut both = inner.to_vec();
314 both.extend_from_slice(old_attrs);
316 if let Some(new_id) = parent_module {
317 Attributes::from_ast(old_attrs, Some((inner, new_id)))
319 Attributes::from_ast(&both, None)
324 (old_attrs.clean(cx), old_attrs.cfg(cx.sess()))
328 /// Builds a specific implementation of a type. The `did` could be a type method or trait method.
330 cx: &mut DocContext<'_>,
331 parent_module: impl Into<Option<DefId>>,
333 attrs: Option<Attrs<'_>>,
334 ret: &mut Vec<clean::Item>,
336 if !cx.inlined.insert(did.into()) {
341 let associated_trait = tcx.impl_trait_ref(did);
343 // Only inline impl if the implemented trait is
344 // reachable in rustdoc generated documentation
346 if let Some(traitref) = associated_trait {
347 let did = traitref.def_id;
348 if !cx.cache.access_levels.is_public(did) {
352 if let Some(stab) = tcx.lookup_stability(did) {
353 if stab.level.is_unstable() && stab.feature == sym::rustc_private {
360 let impl_item = match did.as_local() {
362 let hir_id = tcx.hir().local_def_id_to_hir_id(did);
363 match &tcx.hir().expect_item(hir_id).kind {
364 hir::ItemKind::Impl(impl_) => Some(impl_),
365 _ => panic!("`DefID` passed to `build_impl` is not an `impl"),
371 let for_ = match &impl_item {
372 Some(impl_) => impl_.self_ty.clean(cx),
373 None => tcx.type_of(did).clean(cx),
376 // Only inline impl if the implementing type is
377 // reachable in rustdoc generated documentation
379 if let Some(did) = for_.def_id() {
380 if !cx.cache.access_levels.is_public(did) {
384 if let Some(stab) = tcx.lookup_stability(did) {
385 if stab.level.is_unstable() && stab.feature == sym::rustc_private {
392 let document_hidden = cx.render_options.document_hidden;
393 let predicates = tcx.explicit_predicates_of(did);
394 let (trait_items, generics) = match impl_item {
399 .map(|item| tcx.hir().impl_item(item.id))
401 // Filter out impl items whose corresponding trait item has `doc(hidden)`
402 // not to document such impl items.
403 // For inherent impls, we don't do any filtering, because that's already done in strip_hidden.rs.
405 // When `--document-hidden-items` is passed, we don't
406 // do any filtering, too.
410 if let Some(associated_trait) = associated_trait {
411 let assoc_kind = match item.kind {
412 hir::ImplItemKind::Const(..) => ty::AssocKind::Const,
413 hir::ImplItemKind::Fn(..) => ty::AssocKind::Fn,
414 hir::ImplItemKind::TyAlias(..) => ty::AssocKind::Type,
417 .associated_items(associated_trait.def_id)
418 .find_by_name_and_kind(
422 associated_trait.def_id,
424 .unwrap(); // SAFETY: For all impl items there exists trait item that has the same name.
425 !tcx.get_attrs(trait_item.def_id).lists(sym::doc).has_word(sym::hidden)
430 .map(|item| item.clean(cx))
431 .collect::<Vec<_>>(),
432 impl_.generics.clean(cx),
435 tcx.associated_items(did)
436 .in_definition_order()
438 if associated_trait.is_some() || item.vis == ty::Visibility::Public {
444 .collect::<Vec<_>>(),
445 clean::enter_impl_trait(cx, |cx| (tcx.generics_of(did), predicates).clean(cx)),
448 let polarity = tcx.impl_polarity(did);
449 let trait_ = associated_trait.clean(cx).map(|bound| match bound {
450 clean::GenericBound::TraitBound(polyt, _) => polyt.trait_,
451 clean::GenericBound::Outlives(..) => unreachable!(),
453 if trait_.def_id() == tcx.lang_items().deref_trait() {
454 super::build_deref_target_impls(cx, &trait_items, ret);
457 // Return if the trait itself or any types of the generic parameters are doc(hidden).
458 let mut stack: Vec<&Type> = vec![&for_];
460 if let Some(did) = trait_.as_ref().map(|t| t.res.def_id()) {
461 if tcx.get_attrs(did).lists(sym::doc).has_word(sym::hidden) {
465 if let Some(generics) = trait_.as_ref().and_then(|t| t.generics()) {
466 stack.extend(generics);
469 while let Some(ty) = stack.pop() {
470 if let Some(did) = ty.def_id() {
471 if tcx.get_attrs(did).lists(sym::doc).has_word(sym::hidden) {
475 if let Some(generics) = ty.generics() {
476 stack.extend(generics);
480 if let Some(did) = trait_.as_ref().map(|t| t.res.def_id()) {
481 record_extern_trait(cx, did);
484 let (merged_attrs, cfg) = merge_attrs(cx, parent_module.into(), load_attrs(cx, did), attrs);
485 trace!("merged_attrs={:?}", merged_attrs);
487 trace!("build_impl: impl {:?} for {:?}", trait_.def_id(), for_.def_id());
488 ret.push(clean::Item::from_def_id_and_attrs_and_parts(
491 clean::ImplItem(clean::Impl {
492 span: clean::types::rustc_span(did, cx.tcx),
493 unsafety: hir::Unsafety::Normal,
498 negative_polarity: polarity.clean(cx),
509 cx: &mut DocContext<'_>,
511 visited: &mut FxHashSet<DefId>,
513 let mut items = Vec::new();
515 // If we're re-exporting a re-export it may actually re-export something in
516 // two namespaces, so the target may be listed twice. Make sure we only
517 // visit each node at most once.
518 for &item in cx.tcx.item_children(did).iter() {
519 if item.vis == ty::Visibility::Public {
520 let res = item.res.expect_non_local();
521 if let Some(def_id) = res.mod_def_id() {
522 if did == def_id || !visited.insert(def_id) {
526 if let Res::PrimTy(p) = res {
527 // Primitive types can't be inlined so generate an import instead.
528 let prim_ty = clean::PrimitiveType::from(p);
529 items.push(clean::Item {
531 attrs: box clean::Attributes::default(),
532 def_id: ItemId::Primitive(prim_ty, did.krate),
533 visibility: clean::Public,
534 kind: box clean::ImportItem(clean::Import::new_simple(
536 clean::ImportSource {
539 segments: vec![clean::PathSegment {
540 name: prim_ty.as_sym(),
541 args: clean::GenericArgs::AngleBracketed {
543 bindings: Vec::new(),
553 } else if let Some(i) = try_inline(cx, did, None, res, item.ident.name, None, visited) {
559 let span = clean::Span::new(cx.tcx.def_span(did));
560 clean::Module { items, span }
563 crate fn print_inlined_const(tcx: TyCtxt<'_>, did: DefId) -> String {
564 if let Some(did) = did.as_local() {
565 let hir_id = tcx.hir().local_def_id_to_hir_id(did);
566 rustc_hir_pretty::id_to_string(&tcx.hir(), hir_id)
568 tcx.rendered_const(did)
572 fn build_const(cx: &mut DocContext<'_>, def_id: DefId) -> clean::Constant {
574 type_: cx.tcx.type_of(def_id).clean(cx),
575 kind: clean::ConstantKind::Extern { def_id },
579 fn build_static(cx: &mut DocContext<'_>, did: DefId, mutable: bool) -> clean::Static {
581 type_: cx.tcx.type_of(did).clean(cx),
582 mutability: if mutable { Mutability::Mut } else { Mutability::Not },
588 cx: &mut DocContext<'_>,
591 import_def_id: Option<DefId>,
592 ) -> clean::ItemKind {
593 match CStore::from_tcx(cx.tcx).load_macro_untracked(def_id, cx.sess()) {
594 LoadedMacro::MacroDef(item_def, _) => {
595 if let ast::ItemKind::MacroDef(ref def) = item_def.kind {
596 clean::MacroItem(clean::Macro {
597 source: utils::display_macro_source(
602 cx.tcx.visibility(import_def_id.unwrap_or(def_id)),
609 LoadedMacro::ProcMacro(ext) => clean::ProcMacroItem(clean::ProcMacro {
610 kind: ext.macro_kind(),
611 helpers: ext.helper_attrs,
616 /// A trait's generics clause actually contains all of the predicates for all of
617 /// its associated types as well. We specifically move these clauses to the
618 /// associated types instead when displaying, so when we're generating the
619 /// generics for the trait itself we need to be sure to remove them.
620 /// We also need to remove the implied "recursive" Self: Trait bound.
622 /// The inverse of this filtering logic can be found in the `Clean`
623 /// implementation for `AssociatedType`
624 fn filter_non_trait_generics(trait_did: DefId, mut g: clean::Generics) -> clean::Generics {
625 for pred in &mut g.where_predicates {
627 clean::WherePredicate::BoundPredicate {
628 ty: clean::Generic(ref s),
631 } if *s == kw::SelfUpper => {
632 bounds.retain(|bound| match bound {
633 clean::GenericBound::TraitBound(clean::PolyTrait { trait_, .. }, _) => {
634 trait_.res.def_id() != trait_did
643 g.where_predicates.retain(|pred| match pred {
644 clean::WherePredicate::BoundPredicate {
645 ty: clean::QPath { self_type: box clean::Generic(ref s), trait_, name: _, .. },
648 } => !(bounds.is_empty() || *s == kw::SelfUpper && trait_.res.def_id() == trait_did),
654 /// Supertrait bounds for a trait are also listed in the generics coming from
655 /// the metadata for a crate, so we want to separate those out and create a new
656 /// list of explicit supertrait bounds to render nicely.
657 fn separate_supertrait_bounds(
658 mut g: clean::Generics,
659 ) -> (clean::Generics, Vec<clean::GenericBound>) {
660 let mut ty_bounds = Vec::new();
661 g.where_predicates.retain(|pred| match *pred {
662 clean::WherePredicate::BoundPredicate { ty: clean::Generic(ref s), ref bounds, .. }
663 if *s == kw::SelfUpper =>
665 ty_bounds.extend(bounds.iter().cloned());
673 crate fn record_extern_trait(cx: &mut DocContext<'_>, did: DefId) {
679 if cx.external_traits.borrow().contains_key(&did) || cx.active_extern_traits.contains(&did)
686 cx.active_extern_traits.insert(did);
689 debug!("record_extern_trait: {:?}", did);
690 let trait_ = build_external_trait(cx, did);
692 let trait_ = clean::TraitWithExtraInfo {
694 is_notable: clean::utils::has_doc_flag(cx.tcx.get_attrs(did), sym::notable_trait),
696 cx.external_traits.borrow_mut().insert(did, trait_);
697 cx.active_extern_traits.remove(&did);