1 //! Support for inlining external documentation into the current AST.
7 use rustc_data_structures::fx::FxHashSet;
8 use rustc_data_structures::thin_vec::ThinVec;
10 use rustc_hir::def::{DefKind, Res};
11 use rustc_hir::def_id::DefId;
12 use rustc_hir::definitions::DefPathData;
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_ty_generics, utils, Attributes, AttributesExt,
21 Clean, ImplKind, ItemId, Type, Visibility,
23 use crate::core::DocContext;
24 use crate::formats::item_type::ItemType;
26 type Attrs<'hir> = rustc_middle::ty::Attributes<'hir>;
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.
43 cx: &mut DocContext<'_>,
45 import_def_id: Option<DefId>,
48 attrs: Option<Attrs<'_>>,
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(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), false)
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());
129 clean::Item::from_def_id_and_attrs_and_parts(did, Some(name), kind, box attrs, cx, cfg);
130 if let Some(import_def_id) = import_def_id {
131 // The visibility needs to reflect the one from the reexport and not from the "source" DefId.
132 item.visibility = cx.tcx.visibility(import_def_id).clean(cx);
138 crate fn try_inline_glob(
139 cx: &mut DocContext<'_>,
141 visited: &mut FxHashSet<DefId>,
142 ) -> Option<Vec<clean::Item>> {
143 let did = res.opt_def_id()?;
149 Res::Def(DefKind::Mod, did) => {
150 let m = build_module(cx, did, visited);
153 // glob imports on things like enums aren't inlined even for local exports, so just bail
158 crate fn load_attrs<'hir>(cx: &DocContext<'hir>, did: DefId) -> Attrs<'hir> {
159 cx.tcx.get_attrs(did)
162 /// Record an external fully qualified name in the external_paths cache.
164 /// These names are used later on by HTML rendering to generate things like
165 /// source links back to the original item.
166 crate fn record_extern_fqn(cx: &mut DocContext<'_>, did: DefId, kind: ItemType) {
167 let crate_name = cx.tcx.crate_name(did.krate).to_string();
169 let relative = cx.tcx.def_path(did).data.into_iter().filter_map(|elem| {
170 // Filter out extern blocks
171 (elem.data != DefPathData::ForeignMod).then(|| elem.data.to_string())
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 = clean_ty_generics(cx, cx.tcx.generics_of(did), predicates);
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 // NOTE: generics need to be cleaned before the decl!
233 let generics = clean_ty_generics(cx, cx.tcx.generics_of(did), predicates);
234 let decl = clean_fn_decl_from_did_and_sig(cx, did, sig);
240 header: hir::FnHeader { unsafety: sig.unsafety(), abi: sig.abi(), constness, asyncness },
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_stripped: false,
250 variants: cx.tcx.adt_def(did).variants.iter().map(|v| v.clean(cx)).collect(),
254 fn build_struct(cx: &mut DocContext<'_>, did: DefId) -> clean::Struct {
255 let predicates = cx.tcx.explicit_predicates_of(did);
256 let variant = cx.tcx.adt_def(did).non_enum_variant();
259 struct_type: variant.ctor_kind,
260 generics: clean_ty_generics(cx, cx.tcx.generics_of(did), predicates),
261 fields: variant.fields.iter().map(|x| x.clean(cx)).collect(),
262 fields_stripped: false,
266 fn build_union(cx: &mut DocContext<'_>, did: DefId) -> clean::Union {
267 let predicates = cx.tcx.explicit_predicates_of(did);
268 let variant = cx.tcx.adt_def(did).non_enum_variant();
270 let generics = clean_ty_generics(cx, cx.tcx.generics_of(did), predicates);
271 let fields = variant.fields.iter().map(|x| x.clean(cx)).collect();
272 clean::Union { generics, fields, fields_stripped: false }
275 fn build_type_alias(cx: &mut DocContext<'_>, did: DefId) -> clean::Typedef {
276 let predicates = cx.tcx.explicit_predicates_of(did);
277 let type_ = cx.tcx.type_of(did).clean(cx);
281 generics: clean_ty_generics(cx, cx.tcx.generics_of(did), predicates),
286 /// Builds all inherent implementations of an ADT (struct/union/enum) or Trait item/path/reexport.
287 crate fn build_impls(
288 cx: &mut DocContext<'_>,
289 parent_module: Option<DefId>,
291 attrs: Option<Attrs<'_>>,
292 ret: &mut Vec<clean::Item>,
296 // for each implementation of an item represented by `did`, build the clean::Item for that impl
297 for &did in tcx.inherent_impls(did).iter() {
298 build_impl(cx, parent_module, did, attrs, ret);
302 /// `parent_module` refers to the parent of the re-export, not the original item
304 cx: &mut DocContext<'_>,
305 parent_module: Option<DefId>,
306 old_attrs: Attrs<'_>,
307 new_attrs: Option<Attrs<'_>>,
308 ) -> (clean::Attributes, Option<Arc<clean::cfg::Cfg>>) {
309 // NOTE: If we have additional attributes (from a re-export),
310 // always insert them first. This ensure that re-export
311 // doc comments show up before the original doc comments
312 // when we render them.
313 if let Some(inner) = new_attrs {
314 let mut both = inner.to_vec();
315 both.extend_from_slice(old_attrs);
317 if let Some(new_id) = parent_module {
318 Attributes::from_ast(old_attrs, Some((inner, new_id)))
320 Attributes::from_ast(&both, None)
322 both.cfg(cx.tcx, &cx.cache.hidden_cfg),
325 (old_attrs.clean(cx), old_attrs.cfg(cx.tcx, &cx.cache.hidden_cfg))
329 /// Inline an `impl`, inherent or of a trait. The `did` must be for an `impl`.
331 cx: &mut DocContext<'_>,
332 parent_module: impl Into<Option<DefId>>,
334 attrs: Option<Attrs<'_>>,
335 ret: &mut Vec<clean::Item>,
337 if !cx.inlined.insert(did.into()) {
341 let _prof_timer = cx.tcx.sess.prof.generic_activity("build_extern_trait_impl");
344 let associated_trait = tcx.impl_trait_ref(did);
346 // Only inline impl if the implemented trait is
347 // reachable in rustdoc generated documentation
349 if let Some(traitref) = associated_trait {
350 let did = traitref.def_id;
351 if !cx.cache.access_levels.is_public(did) {
355 if let Some(stab) = tcx.lookup_stability(did) {
356 if stab.level.is_unstable() && stab.feature == sym::rustc_private {
363 let impl_item = match did.as_local() {
364 Some(did) => match &tcx.hir().expect_item(did).kind {
365 hir::ItemKind::Impl(impl_) => Some(impl_),
366 _ => 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(&cx.cache) {
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.is_doc_hidden(trait_item.def_id)
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.is_public() {
444 .collect::<Vec<_>>(),
445 clean::enter_impl_trait(cx, |cx| {
446 clean_ty_generics(cx, tcx.generics_of(did), predicates)
450 let polarity = tcx.impl_polarity(did);
451 let trait_ = associated_trait.map(|t| t.clean(cx));
452 if trait_.as_ref().map(|t| t.def_id()) == tcx.lang_items().deref_trait() {
453 super::build_deref_target_impls(cx, &trait_items, ret);
456 // Return if the trait itself or any types of the generic parameters are doc(hidden).
457 let mut stack: Vec<&Type> = vec![&for_];
459 if let Some(did) = trait_.as_ref().map(|t| t.def_id()) {
460 if tcx.is_doc_hidden(did) {
464 if let Some(generics) = trait_.as_ref().and_then(|t| t.generics()) {
465 stack.extend(generics);
468 while let Some(ty) = stack.pop() {
469 if let Some(did) = ty.def_id(&cx.cache) {
470 if tcx.is_doc_hidden(did) {
474 if let Some(generics) = ty.generics() {
475 stack.extend(generics);
479 if let Some(did) = trait_.as_ref().map(|t| t.def_id()) {
480 record_extern_trait(cx, did);
483 let (merged_attrs, cfg) = merge_attrs(cx, parent_module.into(), load_attrs(cx, did), attrs);
484 trace!("merged_attrs={:?}", merged_attrs);
487 "build_impl: impl {:?} for {:?}",
488 trait_.as_ref().map(|t| t.def_id()),
489 for_.def_id(&cx.cache)
491 ret.push(clean::Item::from_def_id_and_attrs_and_parts(
494 clean::ImplItem(clean::Impl {
495 unsafety: hir::Unsafety::Normal,
501 kind: ImplKind::Normal,
510 cx: &mut DocContext<'_>,
512 visited: &mut FxHashSet<DefId>,
514 let mut items = Vec::new();
516 // If we're re-exporting a re-export it may actually re-export something in
517 // two namespaces, so the target may be listed twice. Make sure we only
518 // visit each node at most once.
519 for &item in cx.tcx.item_children(did).iter() {
520 if item.vis.is_public() {
521 let res = item.res.expect_non_local();
522 if let Some(def_id) = res.mod_def_id() {
523 if did == def_id || !visited.insert(def_id) {
527 if let Res::PrimTy(p) = res {
528 // Primitive types can't be inlined so generate an import instead.
529 let prim_ty = clean::PrimitiveType::from(p);
530 items.push(clean::Item {
532 attrs: box clean::Attributes::default(),
533 def_id: ItemId::Primitive(prim_ty, did.krate),
534 visibility: clean::Public,
535 kind: box clean::ImportItem(clean::Import::new_simple(
537 clean::ImportSource {
540 segments: vec![clean::PathSegment {
541 name: prim_ty.as_sym(),
542 args: clean::GenericArgs::AngleBracketed {
544 bindings: ThinVec::new(),
554 } else if let Some(i) = try_inline(cx, did, None, res, item.ident.name, None, visited) {
560 let span = clean::Span::new(cx.tcx.def_span(did));
561 clean::Module { items, span }
564 crate fn print_inlined_const(tcx: TyCtxt<'_>, did: DefId) -> String {
565 if let Some(did) = did.as_local() {
566 let hir_id = tcx.hir().local_def_id_to_hir_id(did);
567 rustc_hir_pretty::id_to_string(&tcx.hir(), hir_id)
569 tcx.rendered_const(did)
573 fn build_const(cx: &mut DocContext<'_>, def_id: DefId) -> clean::Constant {
575 type_: cx.tcx.type_of(def_id).clean(cx),
576 kind: clean::ConstantKind::Extern { def_id },
580 fn build_static(cx: &mut DocContext<'_>, did: DefId, mutable: bool) -> clean::Static {
582 type_: cx.tcx.type_of(did).clean(cx),
583 mutability: if mutable { Mutability::Mut } else { Mutability::Not },
589 cx: &mut DocContext<'_>,
592 import_def_id: Option<DefId>,
593 ) -> clean::ItemKind {
594 match CStore::from_tcx(cx.tcx).load_macro_untracked(def_id, cx.sess()) {
595 LoadedMacro::MacroDef(item_def, _) => {
596 if let ast::ItemKind::MacroDef(ref def) = item_def.kind {
597 let vis = cx.tcx.visibility(import_def_id.unwrap_or(def_id)).clean(cx);
598 clean::MacroItem(clean::Macro {
599 source: utils::display_macro_source(cx, name, def, def_id, vis),
605 LoadedMacro::ProcMacro(ext) => clean::ProcMacroItem(clean::ProcMacro {
606 kind: ext.macro_kind(),
607 helpers: ext.helper_attrs,
612 /// A trait's generics clause actually contains all of the predicates for all of
613 /// its associated types as well. We specifically move these clauses to the
614 /// associated types instead when displaying, so when we're generating the
615 /// generics for the trait itself we need to be sure to remove them.
616 /// We also need to remove the implied "recursive" Self: Trait bound.
618 /// The inverse of this filtering logic can be found in the `Clean`
619 /// implementation for `AssociatedType`
620 fn filter_non_trait_generics(trait_did: DefId, mut g: clean::Generics) -> clean::Generics {
621 for pred in &mut g.where_predicates {
623 clean::WherePredicate::BoundPredicate {
624 ty: clean::Generic(ref s),
627 } if *s == kw::SelfUpper => {
628 bounds.retain(|bound| match bound {
629 clean::GenericBound::TraitBound(clean::PolyTrait { trait_, .. }, _) => {
630 trait_.def_id() != trait_did
639 g.where_predicates.retain(|pred| match pred {
640 clean::WherePredicate::BoundPredicate {
641 ty: clean::QPath { self_type: box clean::Generic(ref s), trait_, name: _, .. },
644 } => !(bounds.is_empty() || *s == kw::SelfUpper && trait_.def_id() == trait_did),
650 /// Supertrait bounds for a trait are also listed in the generics coming from
651 /// the metadata for a crate, so we want to separate those out and create a new
652 /// list of explicit supertrait bounds to render nicely.
653 fn separate_supertrait_bounds(
654 mut g: clean::Generics,
655 ) -> (clean::Generics, Vec<clean::GenericBound>) {
656 let mut ty_bounds = Vec::new();
657 g.where_predicates.retain(|pred| match *pred {
658 clean::WherePredicate::BoundPredicate { ty: clean::Generic(ref s), ref bounds, .. }
659 if *s == kw::SelfUpper =>
661 ty_bounds.extend(bounds.iter().cloned());
669 crate fn record_extern_trait(cx: &mut DocContext<'_>, did: DefId) {
675 if cx.external_traits.borrow().contains_key(&did) || cx.active_extern_traits.contains(&did)
682 cx.active_extern_traits.insert(did);
685 debug!("record_extern_trait: {:?}", did);
686 let trait_ = build_external_trait(cx, did);
688 let trait_ = clean::TraitWithExtraInfo {
690 is_notable: clean::utils::has_doc_flag(cx.tcx.get_attrs(did), sym::notable_trait),
692 cx.external_traits.borrow_mut().insert(did, trait_);
693 cx.active_extern_traits.remove(&did);