1 //! Support for inlining external documentation into the current AST.
9 use rustc_data_structures::fx::FxHashSet;
11 use rustc_hir::def::{DefKind, Res};
12 use rustc_hir::def_id::DefId;
13 use rustc_hir::Mutability;
14 use rustc_metadata::creader::{CStore, LoadedMacro};
15 use rustc_middle::ty::{self, TyCtxt};
16 use rustc_span::hygiene::MacroKind;
17 use rustc_span::symbol::{kw, sym, Symbol};
20 self, clean_fn_decl_from_did_and_sig, clean_generics, clean_impl_item, clean_middle_assoc_item,
21 clean_middle_field, clean_middle_ty, clean_trait_ref_with_bindings, clean_ty,
22 clean_ty_generics, clean_variant_def, clean_visibility, utils, Attributes, AttributesExt,
23 ImplKind, ItemId, Type, Visibility,
25 use crate::core::DocContext;
26 use crate::formats::item_type::ItemType;
28 /// Attempt to inline a definition into this AST.
30 /// This function will fetch the definition specified, and if it is
31 /// from another crate it will attempt to inline the documentation
32 /// from the other crate into this crate.
34 /// This is primarily used for `pub use` statements which are, in general,
35 /// implementation details. Inlining the documentation should help provide a
36 /// better experience when reading the documentation in this use case.
38 /// The returned value is `None` if the definition could not be inlined,
39 /// and `Some` of a vector of items if it was successfully expanded.
41 /// `parent_module` refers to the parent of the *re-export*, not the original item.
42 pub(crate) fn try_inline(
43 cx: &mut DocContext<'_>,
45 import_def_id: Option<DefId>,
48 attrs: Option<&[ast::Attribute]>,
49 visited: &mut FxHashSet<DefId>,
50 ) -> Option<Vec<clean::Item>> {
51 let did = res.opt_def_id()?;
55 let mut ret = Vec::new();
57 debug!("attrs={:?}", attrs);
58 let attrs_clone = attrs;
60 let kind = match res {
61 Res::Def(DefKind::Trait, did) => {
62 record_extern_fqn(cx, did, ItemType::Trait);
63 build_impls(cx, Some(parent_module), did, attrs, &mut ret);
64 clean::TraitItem(Box::new(build_external_trait(cx, did)))
66 Res::Def(DefKind::Fn, did) => {
67 record_extern_fqn(cx, did, ItemType::Function);
68 clean::FunctionItem(build_external_function(cx, did))
70 Res::Def(DefKind::Struct, did) => {
71 record_extern_fqn(cx, did, ItemType::Struct);
72 build_impls(cx, Some(parent_module), did, attrs, &mut ret);
73 clean::StructItem(build_struct(cx, did))
75 Res::Def(DefKind::Union, did) => {
76 record_extern_fqn(cx, did, ItemType::Union);
77 build_impls(cx, Some(parent_module), did, attrs, &mut ret);
78 clean::UnionItem(build_union(cx, did))
80 Res::Def(DefKind::TyAlias, did) => {
81 record_extern_fqn(cx, did, ItemType::Typedef);
82 build_impls(cx, Some(parent_module), did, attrs, &mut ret);
83 clean::TypedefItem(build_type_alias(cx, did))
85 Res::Def(DefKind::Enum, did) => {
86 record_extern_fqn(cx, did, ItemType::Enum);
87 build_impls(cx, Some(parent_module), did, attrs, &mut ret);
88 clean::EnumItem(build_enum(cx, did))
90 Res::Def(DefKind::ForeignTy, did) => {
91 record_extern_fqn(cx, did, ItemType::ForeignType);
92 build_impls(cx, Some(parent_module), did, attrs, &mut ret);
93 clean::ForeignTypeItem
95 // Never inline enum variants but leave them shown as re-exports.
96 Res::Def(DefKind::Variant, _) => return None,
97 // Assume that enum variants and struct types are re-exported next to
98 // their constructors.
99 Res::Def(DefKind::Ctor(..), _) | Res::SelfCtor(..) => return Some(Vec::new()),
100 Res::Def(DefKind::Mod, did) => {
101 record_extern_fqn(cx, did, ItemType::Module);
102 clean::ModuleItem(build_module(cx, did, visited))
104 Res::Def(DefKind::Static(_), did) => {
105 record_extern_fqn(cx, did, ItemType::Static);
106 clean::StaticItem(build_static(cx, did, cx.tcx.is_mutable_static(did)))
108 Res::Def(DefKind::Const, did) => {
109 record_extern_fqn(cx, did, ItemType::Constant);
110 clean::ConstantItem(build_const(cx, did))
112 Res::Def(DefKind::Macro(kind), did) => {
113 let mac = build_macro(cx, did, name, import_def_id);
115 let type_kind = match kind {
116 MacroKind::Bang => ItemType::Macro,
117 MacroKind::Attr => ItemType::ProcAttribute,
118 MacroKind::Derive => ItemType::ProcDerive,
120 record_extern_fqn(cx, did, type_kind);
126 let (attrs, cfg) = merge_attrs(cx, Some(parent_module), load_attrs(cx, did), attrs_clone);
127 cx.inlined.insert(did.into());
128 let mut item = clean::Item::from_def_id_and_attrs_and_parts(
136 if let Some(import_def_id) = import_def_id {
137 // The visibility needs to reflect the one from the reexport and not from the "source" DefId.
138 item.visibility = clean_visibility(cx.tcx.visibility(import_def_id));
144 pub(crate) fn try_inline_glob(
145 cx: &mut DocContext<'_>,
147 visited: &mut FxHashSet<DefId>,
148 inlined_names: &mut FxHashSet<(ItemType, Symbol)>,
149 ) -> Option<Vec<clean::Item>> {
150 let did = res.opt_def_id()?;
156 Res::Def(DefKind::Mod, did) => {
157 let mut items = build_module_items(cx, did, visited, inlined_names);
158 items.drain_filter(|item| {
159 if let Some(name) = item.name {
160 // If an item with the same type and name already exists,
161 // it takes priority over the inlined stuff.
162 !inlined_names.insert((item.type_(), name))
169 // glob imports on things like enums aren't inlined even for local exports, so just bail
174 pub(crate) fn load_attrs<'hir>(cx: &DocContext<'hir>, did: DefId) -> &'hir [ast::Attribute] {
175 cx.tcx.get_attrs_unchecked(did)
178 /// Record an external fully qualified name in the external_paths cache.
180 /// These names are used later on by HTML rendering to generate things like
181 /// source links back to the original item.
182 pub(crate) fn record_extern_fqn(cx: &mut DocContext<'_>, did: DefId, kind: ItemType) {
183 let crate_name = cx.tcx.crate_name(did.krate);
186 cx.tcx.def_path(did).data.into_iter().filter_map(|elem| elem.data.get_opt_name());
187 let fqn = if let ItemType::Macro = kind {
188 // Check to see if it is a macro 2.0 or built-in macro
190 CStore::from_tcx(cx.tcx).load_macro_untracked(did, cx.sess()),
191 LoadedMacro::MacroDef(def, _)
192 if matches!(&def.kind, ast::ItemKind::MacroDef(ast_def)
193 if !ast_def.macro_rules)
195 once(crate_name).chain(relative).collect()
197 vec![crate_name, relative.last().expect("relative was empty")]
200 once(crate_name).chain(relative).collect()
204 cx.cache.exact_paths.insert(did, fqn);
206 cx.cache.external_paths.insert(did, (fqn, kind));
210 pub(crate) fn build_external_trait(cx: &mut DocContext<'_>, did: DefId) -> clean::Trait {
213 .associated_items(did)
214 .in_definition_order()
216 // When building an external trait, the cleaned trait will have all items public,
217 // which causes methods to have a `pub` prefix, which is invalid since items in traits
218 // can not have a visibility prefix. Thus we override the visibility here manually.
219 // See https://github.com/rust-lang/rust/issues/81274
220 clean::Item { visibility: Visibility::Inherited, ..clean_middle_assoc_item(item, cx) }
224 let predicates = cx.tcx.predicates_of(did);
225 let generics = clean_ty_generics(cx, cx.tcx.generics_of(did), predicates);
226 let generics = filter_non_trait_generics(did, generics);
227 let (generics, supertrait_bounds) = separate_supertrait_bounds(generics);
228 clean::Trait { def_id: did, generics, items: trait_items, bounds: supertrait_bounds }
231 fn build_external_function<'tcx>(cx: &mut DocContext<'tcx>, did: DefId) -> Box<clean::Function> {
232 let sig = cx.tcx.fn_sig(did);
234 let predicates = cx.tcx.predicates_of(did);
235 let (generics, decl) = clean::enter_impl_trait(cx, |cx| {
236 // NOTE: generics need to be cleaned before the decl!
237 let generics = clean_ty_generics(cx, cx.tcx.generics_of(did), predicates);
238 let decl = clean_fn_decl_from_did_and_sig(cx, Some(did), sig);
241 Box::new(clean::Function { decl, generics })
244 fn build_enum(cx: &mut DocContext<'_>, did: DefId) -> clean::Enum {
245 let predicates = cx.tcx.explicit_predicates_of(did);
248 generics: clean_ty_generics(cx, cx.tcx.generics_of(did), predicates),
249 variants: cx.tcx.adt_def(did).variants().iter().map(|v| clean_variant_def(v, cx)).collect(),
253 fn build_struct(cx: &mut DocContext<'_>, did: DefId) -> clean::Struct {
254 let predicates = cx.tcx.explicit_predicates_of(did);
255 let variant = cx.tcx.adt_def(did).non_enum_variant();
258 struct_type: variant.ctor_kind,
259 generics: clean_ty_generics(cx, cx.tcx.generics_of(did), predicates),
260 fields: variant.fields.iter().map(|x| clean_middle_field(x, cx)).collect(),
264 fn build_union(cx: &mut DocContext<'_>, did: DefId) -> clean::Union {
265 let predicates = cx.tcx.explicit_predicates_of(did);
266 let variant = cx.tcx.adt_def(did).non_enum_variant();
268 let generics = clean_ty_generics(cx, cx.tcx.generics_of(did), predicates);
269 let fields = variant.fields.iter().map(|x| clean_middle_field(x, cx)).collect();
270 clean::Union { generics, fields }
273 fn build_type_alias(cx: &mut DocContext<'_>, did: DefId) -> Box<clean::Typedef> {
274 let predicates = cx.tcx.explicit_predicates_of(did);
275 let type_ = clean_middle_ty(cx.tcx.type_of(did), cx, Some(did));
277 Box::new(clean::Typedef {
279 generics: clean_ty_generics(cx, cx.tcx.generics_of(did), predicates),
284 /// Builds all inherent implementations of an ADT (struct/union/enum) or Trait item/path/reexport.
285 pub(crate) fn build_impls(
286 cx: &mut DocContext<'_>,
287 parent_module: Option<DefId>,
289 attrs: Option<&[ast::Attribute]>,
290 ret: &mut Vec<clean::Item>,
292 let _prof_timer = cx.tcx.sess.prof.generic_activity("build_inherent_impls");
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
302 pub(crate) fn merge_attrs(
303 cx: &mut DocContext<'_>,
304 parent_module: Option<DefId>,
305 old_attrs: &[ast::Attribute],
306 new_attrs: Option<&[ast::Attribute]>,
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_with_additional(old_attrs, (inner, new_id))
319 Attributes::from_ast(&both)
321 both.cfg(cx.tcx, &cx.cache.hidden_cfg),
324 (Attributes::from_ast(&old_attrs), old_attrs.cfg(cx.tcx, &cx.cache.hidden_cfg))
328 /// Inline an `impl`, inherent or of a trait. The `did` must be for an `impl`.
329 pub(crate) fn build_impl(
330 cx: &mut DocContext<'_>,
331 parent_module: Option<DefId>,
333 attrs: Option<&[ast::Attribute]>,
334 ret: &mut Vec<clean::Item>,
336 if !cx.inlined.insert(did.into()) {
340 let _prof_timer = cx.tcx.sess.prof.generic_activity("build_impl");
343 let associated_trait = tcx.impl_trait_ref(did);
345 // Only inline impl if the implemented trait is
346 // reachable in rustdoc generated documentation
348 if let Some(traitref) = associated_trait {
349 let did = traitref.def_id;
350 if !cx.cache.access_levels.is_public(did) {
354 if let Some(stab) = tcx.lookup_stability(did) {
355 if stab.is_unstable() && stab.feature == sym::rustc_private {
362 let impl_item = match did.as_local() {
363 Some(did) => match &tcx.hir().expect_item(did).kind {
364 hir::ItemKind::Impl(impl_) => Some(impl_),
365 _ => panic!("`DefID` passed to `build_impl` is not an `impl"),
370 let for_ = match &impl_item {
371 Some(impl_) => clean_ty(impl_.self_ty, cx),
372 None => clean_middle_ty(tcx.type_of(did), cx, Some(did)),
375 // Only inline impl if the implementing type is
376 // reachable in rustdoc generated documentation
378 if let Some(did) = for_.def_id(&cx.cache) {
379 if !cx.cache.access_levels.is_public(did) {
383 if let Some(stab) = tcx.lookup_stability(did) {
384 if stab.is_unstable() && stab.feature == sym::rustc_private {
391 let document_hidden = cx.render_options.document_hidden;
392 let predicates = tcx.explicit_predicates_of(did);
393 let (trait_items, generics) = match impl_item {
398 .map(|item| tcx.hir().impl_item(item.id))
400 // Filter out impl items whose corresponding trait item has `doc(hidden)`
401 // not to document such impl items.
402 // For inherent impls, we don't do any filtering, because that's already done in strip_hidden.rs.
404 // When `--document-hidden-items` is passed, we don't
405 // do any filtering, too.
409 if let Some(associated_trait) = associated_trait {
410 let assoc_kind = match item.kind {
411 hir::ImplItemKind::Const(..) => ty::AssocKind::Const,
412 hir::ImplItemKind::Fn(..) => ty::AssocKind::Fn,
413 hir::ImplItemKind::TyAlias(..) => ty::AssocKind::Type,
416 .associated_items(associated_trait.def_id)
417 .find_by_name_and_kind(
421 associated_trait.def_id,
423 .unwrap(); // SAFETY: For all impl items there exists trait item that has the same name.
424 !tcx.is_doc_hidden(trait_item.def_id)
429 .map(|item| clean_impl_item(item, cx))
430 .collect::<Vec<_>>(),
431 clean_generics(impl_.generics, cx),
434 tcx.associated_items(did)
435 .in_definition_order()
437 // If this is a trait impl, filter out associated items whose corresponding item
438 // in the associated trait is marked `doc(hidden)`.
439 // If this is an inherent impl, filter out private associated items.
440 if let Some(associated_trait) = associated_trait {
442 .associated_items(associated_trait.def_id)
443 .find_by_name_and_kind(
447 associated_trait.def_id,
449 .unwrap(); // corresponding associated item has to exist
450 !tcx.is_doc_hidden(trait_item.def_id)
452 item.visibility(tcx).is_public()
455 .map(|item| clean_middle_assoc_item(item, cx))
456 .collect::<Vec<_>>(),
457 clean::enter_impl_trait(cx, |cx| {
458 clean_ty_generics(cx, tcx.generics_of(did), predicates)
462 let polarity = tcx.impl_polarity(did);
463 let trait_ = associated_trait.map(|t| clean_trait_ref_with_bindings(cx, t, ThinVec::new()));
464 if trait_.as_ref().map(|t| t.def_id()) == tcx.lang_items().deref_trait() {
465 super::build_deref_target_impls(cx, &trait_items, ret);
468 // Return if the trait itself or any types of the generic parameters are doc(hidden).
469 let mut stack: Vec<&Type> = vec![&for_];
471 if let Some(did) = trait_.as_ref().map(|t| t.def_id()) {
472 if tcx.is_doc_hidden(did) {
476 if let Some(generics) = trait_.as_ref().and_then(|t| t.generics()) {
477 stack.extend(generics);
480 while let Some(ty) = stack.pop() {
481 if let Some(did) = ty.def_id(&cx.cache) {
482 if tcx.is_doc_hidden(did) {
486 if let Some(generics) = ty.generics() {
487 stack.extend(generics);
491 if let Some(did) = trait_.as_ref().map(|t| t.def_id()) {
492 record_extern_trait(cx, did);
495 let (merged_attrs, cfg) = merge_attrs(cx, parent_module, load_attrs(cx, did), attrs);
496 trace!("merged_attrs={:?}", merged_attrs);
499 "build_impl: impl {:?} for {:?}",
500 trait_.as_ref().map(|t| t.def_id()),
501 for_.def_id(&cx.cache)
503 ret.push(clean::Item::from_def_id_and_attrs_and_parts(
506 clean::ImplItem(Box::new(clean::Impl {
507 unsafety: hir::Unsafety::Normal,
513 kind: if utils::has_doc_flag(tcx, did, sym::fake_variadic) {
514 ImplKind::FakeVaradic
519 Box::new(merged_attrs),
526 cx: &mut DocContext<'_>,
528 visited: &mut FxHashSet<DefId>,
530 let items = build_module_items(cx, did, visited, &mut FxHashSet::default());
532 let span = clean::Span::new(cx.tcx.def_span(did));
533 clean::Module { items, span }
536 fn build_module_items(
537 cx: &mut DocContext<'_>,
539 visited: &mut FxHashSet<DefId>,
540 inlined_names: &mut FxHashSet<(ItemType, Symbol)>,
541 ) -> Vec<clean::Item> {
542 let mut items = Vec::new();
544 // If we're re-exporting a re-export it may actually re-export something in
545 // two namespaces, so the target may be listed twice. Make sure we only
546 // visit each node at most once.
547 for &item in cx.tcx.module_children(did).iter() {
548 if item.vis.is_public() {
549 let res = item.res.expect_non_local();
550 if let Some(def_id) = res.mod_def_id() {
551 // If we're inlining a glob import, it's possible to have
552 // two distinct modules with the same name. We don't want to
553 // inline it, or mark any of its contents as visited.
555 || inlined_names.contains(&(ItemType::Module, item.ident.name))
556 || !visited.insert(def_id)
561 if let Res::PrimTy(p) = res {
562 // Primitive types can't be inlined so generate an import instead.
563 let prim_ty = clean::PrimitiveType::from(p);
564 items.push(clean::Item {
566 attrs: Box::new(clean::Attributes::default()),
567 item_id: ItemId::Primitive(prim_ty, did.krate),
568 visibility: clean::Public,
569 kind: Box::new(clean::ImportItem(clean::Import::new_simple(
571 clean::ImportSource {
574 segments: vec![clean::PathSegment {
575 name: prim_ty.as_sym(),
576 args: clean::GenericArgs::AngleBracketed {
577 args: Default::default(),
578 bindings: ThinVec::new(),
588 } else if let Some(i) = try_inline(cx, did, None, res, item.ident.name, None, visited) {
597 pub(crate) fn print_inlined_const(tcx: TyCtxt<'_>, did: DefId) -> String {
598 if let Some(did) = did.as_local() {
599 let hir_id = tcx.hir().local_def_id_to_hir_id(did);
600 rustc_hir_pretty::id_to_string(&tcx.hir(), hir_id)
602 tcx.rendered_const(did).clone()
606 fn build_const(cx: &mut DocContext<'_>, def_id: DefId) -> clean::Constant {
608 type_: clean_middle_ty(cx.tcx.type_of(def_id), cx, Some(def_id)),
609 kind: clean::ConstantKind::Extern { def_id },
613 fn build_static(cx: &mut DocContext<'_>, did: DefId, mutable: bool) -> clean::Static {
615 type_: clean_middle_ty(cx.tcx.type_of(did), cx, Some(did)),
616 mutability: if mutable { Mutability::Mut } else { Mutability::Not },
622 cx: &mut DocContext<'_>,
625 import_def_id: Option<DefId>,
626 ) -> clean::ItemKind {
627 match CStore::from_tcx(cx.tcx).load_macro_untracked(def_id, cx.sess()) {
628 LoadedMacro::MacroDef(item_def, _) => {
629 if let ast::ItemKind::MacroDef(ref def) = item_def.kind {
630 let vis = clean_visibility(cx.tcx.visibility(import_def_id.unwrap_or(def_id)));
631 clean::MacroItem(clean::Macro {
632 source: utils::display_macro_source(cx, name, def, def_id, vis),
638 LoadedMacro::ProcMacro(ext) => clean::ProcMacroItem(clean::ProcMacro {
639 kind: ext.macro_kind(),
640 helpers: ext.helper_attrs,
645 /// A trait's generics clause actually contains all of the predicates for all of
646 /// its associated types as well. We specifically move these clauses to the
647 /// associated types instead when displaying, so when we're generating the
648 /// generics for the trait itself we need to be sure to remove them.
649 /// We also need to remove the implied "recursive" Self: Trait bound.
651 /// The inverse of this filtering logic can be found in the `Clean`
652 /// implementation for `AssociatedType`
653 fn filter_non_trait_generics(trait_did: DefId, mut g: clean::Generics) -> clean::Generics {
654 for pred in &mut g.where_predicates {
656 clean::WherePredicate::BoundPredicate {
657 ty: clean::Generic(ref s),
660 } if *s == kw::SelfUpper => {
661 bounds.retain(|bound| match bound {
662 clean::GenericBound::TraitBound(clean::PolyTrait { trait_, .. }, _) => {
663 trait_.def_id() != trait_did
672 g.where_predicates.retain(|pred| match pred {
673 clean::WherePredicate::BoundPredicate {
674 ty: clean::QPath(box clean::QPathData { self_type: clean::Generic(ref s), trait_, .. }),
677 } => !(bounds.is_empty() || *s == kw::SelfUpper && trait_.def_id() == trait_did),
683 /// Supertrait bounds for a trait are also listed in the generics coming from
684 /// the metadata for a crate, so we want to separate those out and create a new
685 /// list of explicit supertrait bounds to render nicely.
686 fn separate_supertrait_bounds(
687 mut g: clean::Generics,
688 ) -> (clean::Generics, Vec<clean::GenericBound>) {
689 let mut ty_bounds = Vec::new();
690 g.where_predicates.retain(|pred| match *pred {
691 clean::WherePredicate::BoundPredicate { ty: clean::Generic(ref s), ref bounds, .. }
692 if *s == kw::SelfUpper =>
694 ty_bounds.extend(bounds.iter().cloned());
702 pub(crate) fn record_extern_trait(cx: &mut DocContext<'_>, did: DefId) {
708 if cx.external_traits.borrow().contains_key(&did) || cx.active_extern_traits.contains(&did)
715 cx.active_extern_traits.insert(did);
718 debug!("record_extern_trait: {:?}", did);
719 let trait_ = build_external_trait(cx, did);
721 let trait_ = clean::TraitWithExtraInfo {
723 is_notable: clean::utils::has_doc_flag(cx.tcx, did, sym::notable_trait),
725 cx.external_traits.borrow_mut().insert(did, trait_);
726 cx.active_extern_traits.remove(&did);