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::LoadedMacro;
13 use rustc_middle::ty::{self, TyCtxt};
14 use rustc_span::hygiene::MacroKind;
15 use rustc_span::symbol::{kw, sym, Symbol};
19 self, Attributes, AttributesExt, FakeDefId, GetDefId, NestedAttributesExt, ToSource, Type,
21 use crate::core::DocContext;
22 use crate::formats::item_type::ItemType;
24 use super::{Clean, Visibility};
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<'_>,
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);
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());
127 ret.push(clean::Item::from_def_id_and_attrs_and_parts(
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 // extern blocks have an empty name
171 let s = elem.data.to_string();
172 if !s.is_empty() { Some(s) } else { None }
174 let fqn = if let ItemType::Macro = kind {
175 // Check to see if it is a macro 2.0 or built-in macro
177 cx.enter_resolver(|r| r.cstore().load_macro_untracked(did, cx.sess())),
178 LoadedMacro::MacroDef(def, _)
179 if matches!(&def.kind, ast::ItemKind::MacroDef(ast_def)
180 if !ast_def.macro_rules)
182 once(crate_name).chain(relative).collect()
184 vec![crate_name, relative.last().expect("relative was empty")]
187 once(crate_name).chain(relative).collect()
191 cx.cache.exact_paths.insert(did, fqn);
193 cx.cache.external_paths.insert(did, (fqn, kind));
197 crate fn build_external_trait(cx: &mut DocContext<'_>, did: DefId) -> clean::Trait {
200 .associated_items(did)
201 .in_definition_order()
203 // When building an external trait, the cleaned trait will have all items public,
204 // which causes methods to have a `pub` prefix, which is invalid since items in traits
205 // can not have a visibility prefix. Thus we override the visibility here manually.
206 // See https://github.com/rust-lang/rust/issues/81274
207 clean::Item { visibility: Visibility::Inherited, ..item.clean(cx) }
211 let predicates = cx.tcx.predicates_of(did);
212 let generics = (cx.tcx.generics_of(did), predicates).clean(cx);
213 let generics = filter_non_trait_generics(did, generics);
214 let (generics, supertrait_bounds) = separate_supertrait_bounds(generics);
215 let is_auto = cx.tcx.trait_is_auto(did);
217 unsafety: cx.tcx.trait_def(did).unsafety,
220 bounds: supertrait_bounds,
225 fn build_external_function(cx: &mut DocContext<'_>, did: DefId) -> clean::Function {
226 let sig = cx.tcx.fn_sig(did);
229 if cx.tcx.is_const_fn_raw(did) { hir::Constness::Const } else { hir::Constness::NotConst };
230 let asyncness = cx.tcx.asyncness(did);
231 let predicates = cx.tcx.predicates_of(did);
232 let (generics, decl) = clean::enter_impl_trait(cx, |cx| {
233 ((cx.tcx.generics_of(did), predicates).clean(cx), (did, sig).clean(cx))
238 header: hir::FnHeader { unsafety: sig.unsafety(), abi: sig.abi(), constness, asyncness },
242 fn build_enum(cx: &mut DocContext<'_>, did: DefId) -> clean::Enum {
243 let predicates = cx.tcx.explicit_predicates_of(did);
246 generics: (cx.tcx.generics_of(did), predicates).clean(cx),
247 variants_stripped: false,
248 variants: cx.tcx.adt_def(did).variants.clean(cx),
252 fn build_struct(cx: &mut DocContext<'_>, did: DefId) -> clean::Struct {
253 let predicates = cx.tcx.explicit_predicates_of(did);
254 let variant = cx.tcx.adt_def(did).non_enum_variant();
257 struct_type: variant.ctor_kind,
258 generics: (cx.tcx.generics_of(did), predicates).clean(cx),
259 fields: variant.fields.clean(cx),
260 fields_stripped: false,
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();
269 generics: (cx.tcx.generics_of(did), predicates).clean(cx),
270 fields: variant.fields.clean(cx),
271 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: (cx.tcx.generics_of(did), predicates).clean(cx),
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)
325 (old_attrs.clean(cx), old_attrs.cfg(cx.sess()))
329 /// Builds a specific implementation of a type. The `did` could be a type method or trait method.
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()) {
342 let associated_trait = tcx.impl_trait_ref(did);
344 // Only inline impl if the implemented trait is
345 // reachable in rustdoc generated documentation
347 if let Some(traitref) = associated_trait {
348 let did = traitref.def_id;
349 if !cx.cache.access_levels.is_public(did) {
353 if let Some(stab) = tcx.lookup_stability(did) {
354 if stab.level.is_unstable() && stab.feature == sym::rustc_private {
361 let impl_item = match did.as_local() {
363 let hir_id = tcx.hir().local_def_id_to_hir_id(did);
364 match &tcx.hir().expect_item(hir_id).kind {
365 hir::ItemKind::Impl(impl_) => Some(impl_),
366 _ => panic!("`DefID` passed to `build_impl` is not an `impl"),
372 let for_ = match &impl_item {
373 Some(impl_) => impl_.self_ty.clean(cx),
374 None => tcx.type_of(did).clean(cx),
377 // Only inline impl if the implementing type is
378 // reachable in rustdoc generated documentation
380 if let Some(did) = for_.def_id() {
381 if !cx.cache.access_levels.is_public(did) {
385 if let Some(stab) = tcx.lookup_stability(did) {
386 if stab.level.is_unstable() && stab.feature == sym::rustc_private {
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).clean(cx))
400 .collect::<Vec<_>>(),
401 impl_.generics.clean(cx),
404 tcx.associated_items(did)
405 .in_definition_order()
407 if associated_trait.is_some() || item.vis == ty::Visibility::Public {
413 .collect::<Vec<_>>(),
414 clean::enter_impl_trait(cx, |cx| (tcx.generics_of(did), predicates).clean(cx)),
417 let polarity = tcx.impl_polarity(did);
418 let trait_ = associated_trait.clean(cx).map(|bound| match bound {
419 clean::GenericBound::TraitBound(polyt, _) => polyt.trait_,
420 clean::GenericBound::Outlives(..) => unreachable!(),
422 if trait_.def_id() == tcx.lang_items().deref_trait() {
423 super::build_deref_target_impls(cx, &trait_items, ret);
426 // Return if the trait itself or any types of the generic parameters are doc(hidden).
427 let mut stack: Vec<&Type> = trait_.iter().collect();
429 while let Some(ty) = stack.pop() {
430 if let Some(did) = ty.def_id() {
431 if cx.tcx.get_attrs(did).lists(sym::doc).has_word(sym::hidden) {
435 if let Some(generics) = ty.generics() {
436 stack.extend(generics);
440 if let Some(trait_did) = trait_.def_id() {
441 record_extern_trait(cx, trait_did);
444 let (merged_attrs, cfg) = merge_attrs(cx, parent_module.into(), load_attrs(cx, did), attrs);
445 debug!("merged_attrs={:?}", merged_attrs);
447 debug!("build_impl: impl {:?} for {:?}", trait_.def_id(), for_.def_id());
448 ret.push(clean::Item::from_def_id_and_attrs_and_parts(
451 clean::ImplItem(clean::Impl {
452 span: clean::types::rustc_span(did, cx.tcx),
453 unsafety: hir::Unsafety::Normal,
458 negative_polarity: polarity.clean(cx),
469 cx: &mut DocContext<'_>,
471 visited: &mut FxHashSet<DefId>,
473 let mut items = Vec::new();
475 // If we're re-exporting a re-export it may actually re-export something in
476 // two namespaces, so the target may be listed twice. Make sure we only
477 // visit each node at most once.
478 for &item in cx.tcx.item_children(did).iter() {
479 if item.vis == ty::Visibility::Public {
480 if let Some(def_id) = item.res.mod_def_id() {
481 if did == def_id || !visited.insert(def_id) {
485 if let Res::PrimTy(p) = item.res {
486 // Primitive types can't be inlined so generate an import instead.
487 items.push(clean::Item {
489 attrs: box clean::Attributes::default(),
490 def_id: FakeDefId::new_fake(did.krate),
491 visibility: clean::Public,
492 kind: box clean::ImportItem(clean::Import::new_simple(
494 clean::ImportSource {
498 segments: vec![clean::PathSegment {
499 name: clean::PrimitiveType::from(p).as_sym(),
500 args: clean::GenericArgs::AngleBracketed {
502 bindings: Vec::new(),
512 } else if let Some(i) = try_inline(cx, did, item.res, item.ident.name, None, visited) {
518 let span = clean::Span::from_rustc_span(cx.tcx.def_span(did));
519 clean::Module { items, span }
522 crate fn print_inlined_const(tcx: TyCtxt<'_>, did: DefId) -> String {
523 if let Some(did) = did.as_local() {
524 let hir_id = tcx.hir().local_def_id_to_hir_id(did);
525 rustc_hir_pretty::id_to_string(&tcx.hir(), hir_id)
527 tcx.rendered_const(did)
531 fn build_const(cx: &mut DocContext<'_>, def_id: DefId) -> clean::Constant {
533 type_: cx.tcx.type_of(def_id).clean(cx),
534 kind: clean::ConstantKind::Extern { def_id },
538 fn build_static(cx: &mut DocContext<'_>, did: DefId, mutable: bool) -> clean::Static {
540 type_: cx.tcx.type_of(did).clean(cx),
541 mutability: if mutable { Mutability::Mut } else { Mutability::Not },
546 fn build_macro(cx: &mut DocContext<'_>, did: DefId, name: Symbol) -> clean::ItemKind {
547 let imported_from = cx.tcx.crate_name(did.krate);
548 match cx.enter_resolver(|r| r.cstore().load_macro_untracked(did, cx.sess())) {
549 LoadedMacro::MacroDef(def, _) => {
550 let matchers: Vec<Span> = if let ast::ItemKind::MacroDef(ref def) = def.kind {
551 let tts: Vec<_> = def.body.inner_tokens().into_trees().collect();
552 tts.chunks(4).map(|arm| arm[0].span()).collect()
557 let source = format!(
558 "macro_rules! {} {{\n{}}}",
562 .map(|span| { format!(" {} => {{ ... }};\n", span.to_src(cx)) })
566 clean::MacroItem(clean::Macro { source, imported_from: Some(imported_from) })
568 LoadedMacro::ProcMacro(ext) => clean::ProcMacroItem(clean::ProcMacro {
569 kind: ext.macro_kind(),
570 helpers: ext.helper_attrs,
575 /// A trait's generics clause actually contains all of the predicates for all of
576 /// its associated types as well. We specifically move these clauses to the
577 /// associated types instead when displaying, so when we're generating the
578 /// generics for the trait itself we need to be sure to remove them.
579 /// We also need to remove the implied "recursive" Self: Trait bound.
581 /// The inverse of this filtering logic can be found in the `Clean`
582 /// implementation for `AssociatedType`
583 fn filter_non_trait_generics(trait_did: DefId, mut g: clean::Generics) -> clean::Generics {
584 for pred in &mut g.where_predicates {
586 clean::WherePredicate::BoundPredicate { ty: clean::Generic(ref s), ref mut bounds }
587 if *s == kw::SelfUpper =>
589 bounds.retain(|bound| match *bound {
590 clean::GenericBound::TraitBound(
591 clean::PolyTrait { trait_: clean::ResolvedPath { did, .. }, .. },
593 ) => did != trait_did,
601 g.where_predicates.retain(|pred| match *pred {
602 clean::WherePredicate::BoundPredicate {
605 self_type: box clean::Generic(ref s),
606 trait_: box clean::ResolvedPath { did, .. },
611 } => !(bounds.is_empty() || *s == kw::SelfUpper && did == trait_did),
617 /// Supertrait bounds for a trait are also listed in the generics coming from
618 /// the metadata for a crate, so we want to separate those out and create a new
619 /// list of explicit supertrait bounds to render nicely.
620 fn separate_supertrait_bounds(
621 mut g: clean::Generics,
622 ) -> (clean::Generics, Vec<clean::GenericBound>) {
623 let mut ty_bounds = Vec::new();
624 g.where_predicates.retain(|pred| match *pred {
625 clean::WherePredicate::BoundPredicate { ty: clean::Generic(ref s), ref bounds }
626 if *s == kw::SelfUpper =>
628 ty_bounds.extend(bounds.iter().cloned());
636 crate fn record_extern_trait(cx: &mut DocContext<'_>, did: DefId) {
642 if cx.external_traits.borrow().contains_key(&did) || cx.active_extern_traits.contains(&did)
649 cx.active_extern_traits.insert(did);
652 debug!("record_extern_trait: {:?}", did);
653 let trait_ = build_external_trait(cx, did);
655 let trait_ = clean::TraitWithExtraInfo {
657 is_notable: clean::utils::has_doc_flag(cx.tcx.get_attrs(did), sym::notable_trait),
659 cx.external_traits.borrow_mut().insert(did, trait_);
660 cx.active_extern_traits.remove(&did);