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};
18 use crate::clean::{self, Attributes, AttributesExt, FakeDefId, GetDefId, ToSource};
19 use crate::core::DocContext;
20 use crate::formats::item_type::ItemType;
22 use super::{Clean, Visibility};
24 type Attrs<'hir> = rustc_middle::ty::Attributes<'hir>;
26 /// Attempt to inline a definition into this AST.
28 /// This function will fetch the definition specified, and if it is
29 /// from another crate it will attempt to inline the documentation
30 /// from the other crate into this crate.
32 /// This is primarily used for `pub use` statements which are, in general,
33 /// implementation details. Inlining the documentation should help provide a
34 /// better experience when reading the documentation in this use case.
36 /// The returned value is `None` if the definition could not be inlined,
37 /// and `Some` of a vector of items if it was successfully expanded.
39 /// `parent_module` refers to the parent of the *re-export*, not the original item.
41 cx: &mut DocContext<'_>,
45 attrs: Option<Attrs<'_>>,
46 visited: &mut FxHashSet<DefId>,
47 ) -> Option<Vec<clean::Item>> {
48 let did = res.opt_def_id()?;
52 let mut ret = Vec::new();
54 debug!("attrs={:?}", attrs);
55 let attrs_clone = attrs;
57 let kind = match res {
58 Res::Def(DefKind::Trait, did) => {
59 record_extern_fqn(cx, did, ItemType::Trait);
60 build_impls(cx, Some(parent_module), did, attrs, &mut ret);
61 clean::TraitItem(build_external_trait(cx, did))
63 Res::Def(DefKind::Fn, did) => {
64 record_extern_fqn(cx, did, ItemType::Function);
65 clean::FunctionItem(build_external_function(cx, did))
67 Res::Def(DefKind::Struct, did) => {
68 record_extern_fqn(cx, did, ItemType::Struct);
69 build_impls(cx, Some(parent_module), did, attrs, &mut ret);
70 clean::StructItem(build_struct(cx, did))
72 Res::Def(DefKind::Union, did) => {
73 record_extern_fqn(cx, did, ItemType::Union);
74 build_impls(cx, Some(parent_module), did, attrs, &mut ret);
75 clean::UnionItem(build_union(cx, did))
77 Res::Def(DefKind::TyAlias, did) => {
78 record_extern_fqn(cx, did, ItemType::Typedef);
79 build_impls(cx, Some(parent_module), did, attrs, &mut ret);
80 clean::TypedefItem(build_type_alias(cx, did), false)
82 Res::Def(DefKind::Enum, did) => {
83 record_extern_fqn(cx, did, ItemType::Enum);
84 build_impls(cx, Some(parent_module), did, attrs, &mut ret);
85 clean::EnumItem(build_enum(cx, did))
87 Res::Def(DefKind::ForeignTy, did) => {
88 record_extern_fqn(cx, did, ItemType::ForeignType);
89 build_impls(cx, Some(parent_module), did, attrs, &mut ret);
90 clean::ForeignTypeItem
92 // Never inline enum variants but leave them shown as re-exports.
93 Res::Def(DefKind::Variant, _) => return None,
94 // Assume that enum variants and struct types are re-exported next to
95 // their constructors.
96 Res::Def(DefKind::Ctor(..), _) | Res::SelfCtor(..) => return Some(Vec::new()),
97 Res::Def(DefKind::Mod, did) => {
98 record_extern_fqn(cx, did, ItemType::Module);
99 clean::ModuleItem(build_module(cx, did, visited))
101 Res::Def(DefKind::Static, did) => {
102 record_extern_fqn(cx, did, ItemType::Static);
103 clean::StaticItem(build_static(cx, did, cx.tcx.is_mutable_static(did)))
105 Res::Def(DefKind::Const, did) => {
106 record_extern_fqn(cx, did, ItemType::Constant);
107 clean::ConstantItem(build_const(cx, did))
109 Res::Def(DefKind::Macro(kind), did) => {
110 let mac = build_macro(cx, did, name);
112 let type_kind = match kind {
113 MacroKind::Bang => ItemType::Macro,
114 MacroKind::Attr => ItemType::ProcAttribute,
115 MacroKind::Derive => ItemType::ProcDerive,
117 record_extern_fqn(cx, did, type_kind);
123 let (attrs, cfg) = merge_attrs(cx, Some(parent_module), load_attrs(cx, did), attrs_clone);
124 cx.inlined.insert(did.into());
125 ret.push(clean::Item::from_def_id_and_attrs_and_parts(
136 crate fn try_inline_glob(
137 cx: &mut DocContext<'_>,
139 visited: &mut FxHashSet<DefId>,
140 ) -> Option<Vec<clean::Item>> {
141 let did = res.opt_def_id()?;
147 Res::Def(DefKind::Mod, did) => {
148 let m = build_module(cx, did, visited);
151 // glob imports on things like enums aren't inlined even for local exports, so just bail
156 crate fn load_attrs<'hir>(cx: &DocContext<'hir>, did: DefId) -> Attrs<'hir> {
157 cx.tcx.get_attrs(did)
160 /// Record an external fully qualified name in the external_paths cache.
162 /// These names are used later on by HTML rendering to generate things like
163 /// source links back to the original item.
164 crate fn record_extern_fqn(cx: &mut DocContext<'_>, did: DefId, kind: ItemType) {
165 let crate_name = cx.tcx.crate_name(did.krate).to_string();
167 let relative = cx.tcx.def_path(did).data.into_iter().filter_map(|elem| {
168 // extern blocks have an empty name
169 let s = elem.data.to_string();
170 if !s.is_empty() { Some(s) } else { None }
172 let fqn = if let ItemType::Macro = kind {
173 // Check to see if it is a macro 2.0 or built-in macro
175 cx.enter_resolver(|r| r.cstore().load_macro_untracked(did, cx.sess())),
176 LoadedMacro::MacroDef(def, _)
177 if matches!(&def.kind, ast::ItemKind::MacroDef(ast_def)
178 if !ast_def.macro_rules)
180 once(crate_name).chain(relative).collect()
182 vec![crate_name, relative.last().expect("relative was empty")]
185 once(crate_name).chain(relative).collect()
189 cx.cache.exact_paths.insert(did, fqn);
191 cx.cache.external_paths.insert(did, (fqn, kind));
195 crate fn build_external_trait(cx: &mut DocContext<'_>, did: DefId) -> clean::Trait {
198 .associated_items(did)
199 .in_definition_order()
201 // When building an external trait, the cleaned trait will have all items public,
202 // which causes methods to have a `pub` prefix, which is invalid since items in traits
203 // can not have a visibility prefix. Thus we override the visibility here manually.
204 // See https://github.com/rust-lang/rust/issues/81274
205 clean::Item { visibility: Visibility::Inherited, ..item.clean(cx) }
209 let predicates = cx.tcx.predicates_of(did);
210 let generics = (cx.tcx.generics_of(did), predicates).clean(cx);
211 let generics = filter_non_trait_generics(did, generics);
212 let (generics, supertrait_bounds) = separate_supertrait_bounds(generics);
213 let is_auto = cx.tcx.trait_is_auto(did);
215 unsafety: cx.tcx.trait_def(did).unsafety,
218 bounds: supertrait_bounds,
223 fn build_external_function(cx: &mut DocContext<'_>, did: DefId) -> clean::Function {
224 let sig = cx.tcx.fn_sig(did);
227 if cx.tcx.is_const_fn_raw(did) { hir::Constness::Const } else { hir::Constness::NotConst };
228 let asyncness = cx.tcx.asyncness(did);
229 let predicates = cx.tcx.predicates_of(did);
230 let (generics, decl) = clean::enter_impl_trait(cx, |cx| {
231 ((cx.tcx.generics_of(did), predicates).clean(cx), (did, sig).clean(cx))
236 header: hir::FnHeader { unsafety: sig.unsafety(), abi: sig.abi(), constness, asyncness },
240 fn build_enum(cx: &mut DocContext<'_>, did: DefId) -> clean::Enum {
241 let predicates = cx.tcx.explicit_predicates_of(did);
244 generics: (cx.tcx.generics_of(did), predicates).clean(cx),
245 variants_stripped: false,
246 variants: cx.tcx.adt_def(did).variants.clean(cx),
250 fn build_struct(cx: &mut DocContext<'_>, did: DefId) -> clean::Struct {
251 let predicates = cx.tcx.explicit_predicates_of(did);
252 let variant = cx.tcx.adt_def(did).non_enum_variant();
255 struct_type: variant.ctor_kind,
256 generics: (cx.tcx.generics_of(did), predicates).clean(cx),
257 fields: variant.fields.clean(cx),
258 fields_stripped: false,
262 fn build_union(cx: &mut DocContext<'_>, did: DefId) -> clean::Union {
263 let predicates = cx.tcx.explicit_predicates_of(did);
264 let variant = cx.tcx.adt_def(did).non_enum_variant();
267 generics: (cx.tcx.generics_of(did), predicates).clean(cx),
268 fields: variant.fields.clean(cx),
269 fields_stripped: false,
273 fn build_type_alias(cx: &mut DocContext<'_>, did: DefId) -> clean::Typedef {
274 let predicates = cx.tcx.explicit_predicates_of(did);
275 let type_ = cx.tcx.type_of(did).clean(cx);
279 generics: (cx.tcx.generics_of(did), predicates).clean(cx),
284 /// Builds all inherent implementations of an ADT (struct/union/enum) or Trait item/path/reexport.
285 crate fn build_impls(
286 cx: &mut DocContext<'_>,
287 parent_module: Option<DefId>,
289 attrs: Option<Attrs<'_>>,
290 ret: &mut Vec<clean::Item>,
294 // for each implementation of an item represented by `did`, build the clean::Item for that impl
295 for &did in tcx.inherent_impls(did).iter() {
296 build_impl(cx, parent_module, did, attrs, ret);
300 /// `parent_module` refers to the parent of the re-export, not the original item
302 cx: &mut DocContext<'_>,
303 parent_module: Option<DefId>,
304 old_attrs: Attrs<'_>,
305 new_attrs: Option<Attrs<'_>>,
306 ) -> (clean::Attributes, Option<Arc<clean::cfg::Cfg>>) {
307 // NOTE: If we have additional attributes (from a re-export),
308 // always insert them first. This ensure that re-export
309 // doc comments show up before the original doc comments
310 // when we render them.
311 if let Some(inner) = new_attrs {
312 let mut both = inner.to_vec();
313 both.extend_from_slice(old_attrs);
315 if let Some(new_id) = parent_module {
316 Attributes::from_ast(old_attrs, Some((inner, new_id)))
318 Attributes::from_ast(&both, None)
323 (old_attrs.clean(cx), old_attrs.cfg(cx.sess()))
327 /// Builds a specific implementation of a type. The `did` could be a type method or trait method.
329 cx: &mut DocContext<'_>,
330 parent_module: impl Into<Option<DefId>>,
332 attrs: Option<Attrs<'_>>,
333 ret: &mut Vec<clean::Item>,
335 if !cx.inlined.insert(did.into()) {
340 let associated_trait = tcx.impl_trait_ref(did);
342 // Only inline impl if the implemented trait is
343 // reachable in rustdoc generated documentation
345 if let Some(traitref) = associated_trait {
346 let did = traitref.def_id;
347 if !cx.cache.access_levels.is_public(did) {
351 if let Some(stab) = tcx.lookup_stability(did) {
352 if stab.level.is_unstable() && stab.feature == sym::rustc_private {
359 let impl_item = match did.as_local() {
361 let hir_id = tcx.hir().local_def_id_to_hir_id(did);
362 match &tcx.hir().expect_item(hir_id).kind {
363 hir::ItemKind::Impl(impl_) => Some(impl_),
364 _ => panic!("`DefID` passed to `build_impl` is not an `impl"),
370 let for_ = match &impl_item {
371 Some(impl_) => impl_.self_ty.clean(cx),
372 None => tcx.type_of(did).clean(cx),
375 // Only inline impl if the implementing type is
376 // reachable in rustdoc generated documentation
378 if let Some(did) = for_.def_id() {
379 if !cx.cache.access_levels.is_public(did) {
383 if let Some(stab) = tcx.lookup_stability(did) {
384 if stab.level.is_unstable() && stab.feature == sym::rustc_private {
391 let predicates = tcx.explicit_predicates_of(did);
392 let (trait_items, generics) = match impl_item {
397 .map(|item| tcx.hir().impl_item(item.id).clean(cx))
398 .collect::<Vec<_>>(),
399 impl_.generics.clean(cx),
402 tcx.associated_items(did)
403 .in_definition_order()
405 if associated_trait.is_some() || item.vis == ty::Visibility::Public {
411 .collect::<Vec<_>>(),
412 clean::enter_impl_trait(cx, |cx| (tcx.generics_of(did), predicates).clean(cx)),
415 let polarity = tcx.impl_polarity(did);
416 let trait_ = associated_trait.clean(cx).map(|bound| match bound {
417 clean::GenericBound::TraitBound(polyt, _) => polyt.trait_,
418 clean::GenericBound::Outlives(..) => unreachable!(),
420 if trait_.def_id() == tcx.lang_items().deref_trait() {
421 super::build_deref_target_impls(cx, &trait_items, ret);
423 if let Some(trait_did) = trait_.def_id() {
424 record_extern_trait(cx, trait_did);
427 let (merged_attrs, cfg) = merge_attrs(cx, parent_module.into(), load_attrs(cx, did), attrs);
428 debug!("merged_attrs={:?}", merged_attrs);
430 debug!("build_impl: impl {:?} for {:?}", trait_.def_id(), for_.def_id());
431 ret.push(clean::Item::from_def_id_and_attrs_and_parts(
434 clean::ImplItem(clean::Impl {
435 span: clean::types::rustc_span(did, cx.tcx),
436 unsafety: hir::Unsafety::Normal,
441 negative_polarity: polarity.clean(cx),
452 cx: &mut DocContext<'_>,
454 visited: &mut FxHashSet<DefId>,
456 let mut items = Vec::new();
458 // If we're re-exporting a re-export it may actually re-export something in
459 // two namespaces, so the target may be listed twice. Make sure we only
460 // visit each node at most once.
461 for &item in cx.tcx.item_children(did).iter() {
462 if item.vis == ty::Visibility::Public {
463 if let Some(def_id) = item.res.mod_def_id() {
464 if did == def_id || !visited.insert(def_id) {
468 if let Res::PrimTy(p) = item.res {
469 // Primitive types can't be inlined so generate an import instead.
470 items.push(clean::Item {
472 attrs: box clean::Attributes::default(),
473 def_id: FakeDefId::new_fake(did.krate),
474 visibility: clean::Public,
475 kind: box clean::ImportItem(clean::Import::new_simple(
477 clean::ImportSource {
481 segments: vec![clean::PathSegment {
482 name: clean::PrimitiveType::from(p).as_sym(),
483 args: clean::GenericArgs::AngleBracketed {
485 bindings: Vec::new(),
495 } else if let Some(i) = try_inline(cx, did, item.res, item.ident.name, None, visited) {
501 let span = clean::Span::from_rustc_span(cx.tcx.def_span(did));
502 clean::Module { items, span }
505 crate fn print_inlined_const(tcx: TyCtxt<'_>, did: DefId) -> String {
506 if let Some(did) = did.as_local() {
507 let hir_id = tcx.hir().local_def_id_to_hir_id(did);
508 rustc_hir_pretty::id_to_string(&tcx.hir(), hir_id)
510 tcx.rendered_const(did)
514 fn build_const(cx: &mut DocContext<'_>, def_id: DefId) -> clean::Constant {
516 type_: cx.tcx.type_of(def_id).clean(cx),
517 kind: clean::ConstantKind::Extern { def_id },
521 fn build_static(cx: &mut DocContext<'_>, did: DefId, mutable: bool) -> clean::Static {
523 type_: cx.tcx.type_of(did).clean(cx),
524 mutability: if mutable { Mutability::Mut } else { Mutability::Not },
529 fn build_macro(cx: &mut DocContext<'_>, did: DefId, name: Symbol) -> clean::ItemKind {
530 let imported_from = cx.tcx.crate_name(did.krate);
531 match cx.enter_resolver(|r| r.cstore().load_macro_untracked(did, cx.sess())) {
532 LoadedMacro::MacroDef(def, _) => {
533 let matchers: Vec<Span> = if let ast::ItemKind::MacroDef(ref def) = def.kind {
534 let tts: Vec<_> = def.body.inner_tokens().into_trees().collect();
535 tts.chunks(4).map(|arm| arm[0].span()).collect()
540 let source = format!(
541 "macro_rules! {} {{\n{}}}",
545 .map(|span| { format!(" {} => {{ ... }};\n", span.to_src(cx)) })
549 clean::MacroItem(clean::Macro { source, imported_from: Some(imported_from) })
551 LoadedMacro::ProcMacro(ext) => clean::ProcMacroItem(clean::ProcMacro {
552 kind: ext.macro_kind(),
553 helpers: ext.helper_attrs,
558 /// A trait's generics clause actually contains all of the predicates for all of
559 /// its associated types as well. We specifically move these clauses to the
560 /// associated types instead when displaying, so when we're generating the
561 /// generics for the trait itself we need to be sure to remove them.
562 /// We also need to remove the implied "recursive" Self: Trait bound.
564 /// The inverse of this filtering logic can be found in the `Clean`
565 /// implementation for `AssociatedType`
566 fn filter_non_trait_generics(trait_did: DefId, mut g: clean::Generics) -> clean::Generics {
567 for pred in &mut g.where_predicates {
569 clean::WherePredicate::BoundPredicate { ty: clean::Generic(ref s), ref mut bounds }
570 if *s == kw::SelfUpper =>
572 bounds.retain(|bound| match *bound {
573 clean::GenericBound::TraitBound(
574 clean::PolyTrait { trait_: clean::ResolvedPath { did, .. }, .. },
576 ) => did != trait_did,
584 g.where_predicates.retain(|pred| match *pred {
585 clean::WherePredicate::BoundPredicate {
588 self_type: box clean::Generic(ref s),
589 trait_: box clean::ResolvedPath { did, .. },
594 } => !(bounds.is_empty() || *s == kw::SelfUpper && did == trait_did),
600 /// Supertrait bounds for a trait are also listed in the generics coming from
601 /// the metadata for a crate, so we want to separate those out and create a new
602 /// list of explicit supertrait bounds to render nicely.
603 fn separate_supertrait_bounds(
604 mut g: clean::Generics,
605 ) -> (clean::Generics, Vec<clean::GenericBound>) {
606 let mut ty_bounds = Vec::new();
607 g.where_predicates.retain(|pred| match *pred {
608 clean::WherePredicate::BoundPredicate { ty: clean::Generic(ref s), ref bounds }
609 if *s == kw::SelfUpper =>
611 ty_bounds.extend(bounds.iter().cloned());
619 crate fn record_extern_trait(cx: &mut DocContext<'_>, did: DefId) {
625 if cx.external_traits.borrow().contains_key(&did) || cx.active_extern_traits.contains(&did)
632 cx.active_extern_traits.insert(did);
635 debug!("record_extern_trait: {:?}", did);
636 let trait_ = build_external_trait(cx, did);
638 let trait_ = clean::TraitWithExtraInfo {
640 is_notable: clean::utils::has_doc_flag(cx.tcx.get_attrs(did), sym::notable_trait),
642 cx.external_traits.borrow_mut().insert(did, trait_);
643 cx.active_extern_traits.remove(&did);