1 //! Support for inlining external documentation into the current AST.
6 use rustc_data_structures::fx::FxHashSet;
8 use rustc_hir::def::{CtorKind, DefKind, Res};
9 use rustc_hir::def_id::DefId;
10 use rustc_hir::Mutability;
11 use rustc_metadata::creader::LoadedMacro;
12 use rustc_span::hygiene::MacroKind;
13 use rustc_span::symbol::sym;
17 use crate::clean::{self, GetDefId, ToSource, TypeKind};
18 use crate::core::DocContext;
23 type Attrs<'hir> = rustc::ty::Attributes<'hir>;
25 /// Attempt to inline a definition into this AST.
27 /// This function will fetch the definition specified, and if it is
28 /// from another crate it will attempt to inline the documentation
29 /// from the other crate into this crate.
31 /// This is primarily used for `pub use` statements which are, in general,
32 /// implementation details. Inlining the documentation should help provide a
33 /// better experience when reading the documentation in this use case.
35 /// The returned value is `None` if the definition could not be inlined,
36 /// and `Some` of a vector of items if it was successfully expanded.
41 attrs: Option<Attrs<'_>>,
42 visited: &mut FxHashSet<DefId>,
43 ) -> Option<Vec<clean::Item>> {
44 let did = if let Some(did) = res.opt_def_id() {
52 let mut ret = Vec::new();
54 let attrs_clone = attrs.clone();
56 let inner = match res {
57 Res::Def(DefKind::Trait, did) => {
58 record_extern_fqn(cx, did, clean::TypeKind::Trait);
59 ret.extend(build_impls(cx, did, attrs));
60 clean::TraitItem(build_external_trait(cx, did))
62 Res::Def(DefKind::Fn, did) => {
63 record_extern_fqn(cx, did, clean::TypeKind::Function);
64 clean::FunctionItem(build_external_function(cx, did))
66 Res::Def(DefKind::Struct, did) => {
67 record_extern_fqn(cx, did, clean::TypeKind::Struct);
68 ret.extend(build_impls(cx, did, attrs));
69 clean::StructItem(build_struct(cx, did))
71 Res::Def(DefKind::Union, did) => {
72 record_extern_fqn(cx, did, clean::TypeKind::Union);
73 ret.extend(build_impls(cx, did, attrs));
74 clean::UnionItem(build_union(cx, did))
76 Res::Def(DefKind::TyAlias, did) => {
77 record_extern_fqn(cx, did, clean::TypeKind::Typedef);
78 ret.extend(build_impls(cx, did, attrs));
79 clean::TypedefItem(build_type_alias(cx, did), false)
81 Res::Def(DefKind::Enum, did) => {
82 record_extern_fqn(cx, did, clean::TypeKind::Enum);
83 ret.extend(build_impls(cx, did, attrs));
84 clean::EnumItem(build_enum(cx, did))
86 Res::Def(DefKind::ForeignTy, did) => {
87 record_extern_fqn(cx, did, clean::TypeKind::Foreign);
88 ret.extend(build_impls(cx, did, attrs));
89 clean::ForeignTypeItem
91 // Never inline enum variants but leave them shown as re-exports.
92 Res::Def(DefKind::Variant, _) => return None,
93 // Assume that enum variants and struct types are re-exported next to
94 // their constructors.
95 Res::Def(DefKind::Ctor(..), _) | Res::SelfCtor(..) => return Some(Vec::new()),
96 Res::Def(DefKind::Mod, did) => {
97 record_extern_fqn(cx, did, clean::TypeKind::Module);
98 clean::ModuleItem(build_module(cx, did, visited))
100 Res::Def(DefKind::Static, did) => {
101 record_extern_fqn(cx, did, clean::TypeKind::Static);
102 clean::StaticItem(build_static(cx, did, cx.tcx.is_mutable_static(did)))
104 Res::Def(DefKind::Const, did) => {
105 record_extern_fqn(cx, did, clean::TypeKind::Const);
106 clean::ConstantItem(build_const(cx, did))
108 Res::Def(DefKind::Macro(kind), did) => {
109 let mac = build_macro(cx, did, name);
111 let type_kind = match kind {
112 MacroKind::Bang => TypeKind::Macro,
113 MacroKind::Attr => TypeKind::Attr,
114 MacroKind::Derive => TypeKind::Derive,
116 record_extern_fqn(cx, did, type_kind);
122 let target_attrs = load_attrs(cx, did);
123 let attrs = merge_attrs(cx, target_attrs, attrs_clone);
125 cx.renderinfo.borrow_mut().inlined.insert(did);
126 ret.push(clean::Item {
127 source: cx.tcx.def_span(did).clean(cx),
128 name: Some(name.clean(cx)),
131 visibility: clean::Public,
132 stability: cx.tcx.lookup_stability(did).clean(cx),
133 deprecation: cx.tcx.lookup_deprecation(did).clean(cx),
139 pub fn try_inline_glob(
142 visited: &mut FxHashSet<DefId>,
143 ) -> Option<Vec<clean::Item>> {
147 let did = res.def_id();
153 Res::Def(DefKind::Mod, did) => {
154 let m = build_module(cx, did, visited);
157 // glob imports on things like enums aren't inlined even for local exports, so just bail
162 pub fn load_attrs<'hir>(cx: &DocContext<'hir>, did: DefId) -> Attrs<'hir> {
163 cx.tcx.get_attrs(did)
166 /// Record an external fully qualified name in the external_paths cache.
168 /// These names are used later on by HTML rendering to generate things like
169 /// source links back to the original item.
170 pub fn record_extern_fqn(cx: &DocContext<'_>, did: DefId, kind: clean::TypeKind) {
171 let crate_name = cx.tcx.crate_name(did.krate).to_string();
173 let relative = cx.tcx.def_path(did).data.into_iter().filter_map(|elem| {
174 // extern blocks have an empty name
175 let s = elem.data.to_string();
176 if !s.is_empty() { Some(s) } else { None }
178 let fqn = if let clean::TypeKind::Macro = kind {
179 vec![crate_name, relative.last().expect("relative was empty")]
181 once(crate_name).chain(relative).collect()
185 cx.renderinfo.borrow_mut().exact_paths.insert(did, fqn);
187 cx.renderinfo.borrow_mut().external_paths.insert(did, (fqn, kind));
191 pub fn build_external_trait(cx: &DocContext<'_>, did: DefId) -> clean::Trait {
192 let auto_trait = cx.tcx.trait_def(did).has_auto_impl;
193 let trait_items = cx.tcx.associated_items(did).map(|item| item.clean(cx)).collect();
194 let predicates = cx.tcx.predicates_of(did);
195 let generics = (cx.tcx.generics_of(did), predicates).clean(cx);
196 let generics = filter_non_trait_generics(did, generics);
197 let (generics, supertrait_bounds) = separate_supertrait_bounds(generics);
198 let is_spotlight = load_attrs(cx, did).clean(cx).has_doc_flag(sym::spotlight);
199 let is_auto = cx.tcx.trait_is_auto(did);
202 unsafety: cx.tcx.trait_def(did).unsafety,
205 bounds: supertrait_bounds,
211 fn build_external_function(cx: &DocContext<'_>, did: DefId) -> clean::Function {
212 let sig = cx.tcx.fn_sig(did);
215 if cx.tcx.is_min_const_fn(did) { hir::Constness::Const } else { hir::Constness::NotConst };
216 let asyncness = cx.tcx.asyncness(did);
217 let predicates = cx.tcx.predicates_of(did);
218 let (generics, decl) = clean::enter_impl_trait(cx, || {
219 ((cx.tcx.generics_of(did), predicates).clean(cx), (did, sig).clean(cx))
221 let (all_types, ret_types) = clean::get_all_types(&generics, &decl, cx);
225 header: hir::FnHeader { unsafety: sig.unsafety(), abi: sig.abi(), constness, asyncness },
231 fn build_enum(cx: &DocContext<'_>, did: DefId) -> clean::Enum {
232 let predicates = cx.tcx.explicit_predicates_of(did);
235 generics: (cx.tcx.generics_of(did), predicates).clean(cx),
236 variants_stripped: false,
237 variants: cx.tcx.adt_def(did).variants.clean(cx),
241 fn build_struct(cx: &DocContext<'_>, did: DefId) -> clean::Struct {
242 let predicates = cx.tcx.explicit_predicates_of(did);
243 let variant = cx.tcx.adt_def(did).non_enum_variant();
246 struct_type: match variant.ctor_kind {
247 CtorKind::Fictive => doctree::Plain,
248 CtorKind::Fn => doctree::Tuple,
249 CtorKind::Const => doctree::Unit,
251 generics: (cx.tcx.generics_of(did), predicates).clean(cx),
252 fields: variant.fields.clean(cx),
253 fields_stripped: false,
257 fn build_union(cx: &DocContext<'_>, did: DefId) -> clean::Union {
258 let predicates = cx.tcx.explicit_predicates_of(did);
259 let variant = cx.tcx.adt_def(did).non_enum_variant();
262 struct_type: doctree::Plain,
263 generics: (cx.tcx.generics_of(did), predicates).clean(cx),
264 fields: variant.fields.clean(cx),
265 fields_stripped: false,
269 fn build_type_alias(cx: &DocContext<'_>, did: DefId) -> clean::Typedef {
270 let predicates = cx.tcx.explicit_predicates_of(did);
273 type_: cx.tcx.type_of(did).clean(cx),
274 generics: (cx.tcx.generics_of(did), predicates).clean(cx),
278 pub fn build_impls(cx: &DocContext<'_>, did: DefId, attrs: Option<Attrs<'_>>) -> Vec<clean::Item> {
280 let mut impls = Vec::new();
282 for &did in tcx.inherent_impls(did).iter() {
283 build_impl(cx, did, attrs.clone(), &mut impls);
292 other_attrs: Option<Attrs<'_>>,
293 ) -> clean::Attributes {
294 let mut merged_attrs: Vec<ast::Attribute> = Vec::with_capacity(attrs.len());
295 // If we have additional attributes (from a re-export),
296 // always insert them first. This ensure that re-export
297 // doc comments show up before the original doc comments
298 // when we render them.
299 if let Some(a) = other_attrs {
300 merged_attrs.extend(a.iter().cloned());
302 merged_attrs.extend(attrs.to_vec());
303 merged_attrs.clean(cx)
309 attrs: Option<Attrs<'_>>,
310 ret: &mut Vec<clean::Item>,
312 if !cx.renderinfo.borrow_mut().inlined.insert(did) {
316 let attrs = merge_attrs(cx, load_attrs(cx, did), attrs);
319 let associated_trait = tcx.impl_trait_ref(did);
321 // Only inline impl if the implemented trait is
322 // reachable in rustdoc generated documentation
324 if let Some(traitref) = associated_trait {
325 if !cx.renderinfo.borrow().access_levels.is_public(traitref.def_id) {
331 let for_ = if let Some(hir_id) = tcx.hir().as_local_hir_id(did) {
332 match tcx.hir().expect_item(hir_id).kind {
333 hir::ItemKind::Impl(.., ref t, _) => t.clean(cx),
334 _ => panic!("did given to build_impl was not an impl"),
337 tcx.type_of(did).clean(cx)
340 // Only inline impl if the implementing type is
341 // reachable in rustdoc generated documentation
343 if let Some(did) = for_.def_id() {
344 if !cx.renderinfo.borrow().access_levels.is_public(did) {
350 let predicates = tcx.explicit_predicates_of(did);
351 let (trait_items, generics) = if let Some(hir_id) = tcx.hir().as_local_hir_id(did) {
352 match tcx.hir().expect_item(hir_id).kind {
353 hir::ItemKind::Impl(.., ref gen, _, _, ref item_ids) => (
354 item_ids.iter().map(|ii| tcx.hir().impl_item(ii.id).clean(cx)).collect::<Vec<_>>(),
357 _ => panic!("did given to build_impl was not an impl"),
361 tcx.associated_items(did)
363 if associated_trait.is_some() || item.vis == ty::Visibility::Public {
369 .collect::<Vec<_>>(),
370 clean::enter_impl_trait(cx, || (tcx.generics_of(did), predicates).clean(cx)),
373 let polarity = tcx.impl_polarity(did);
374 let trait_ = associated_trait.clean(cx).map(|bound| match bound {
375 clean::GenericBound::TraitBound(polyt, _) => polyt.trait_,
376 clean::GenericBound::Outlives(..) => unreachable!(),
378 if trait_.def_id() == tcx.lang_items().deref_trait() {
379 super::build_deref_target_impls(cx, &trait_items, ret);
381 if let Some(trait_did) = trait_.def_id() {
382 record_extern_trait(cx, trait_did);
385 let provided = trait_
388 tcx.provided_trait_methods(did).into_iter().map(|meth| meth.ident.to_string()).collect()
390 .unwrap_or_default();
392 debug!("build_impl: impl {:?} for {:?}", trait_.def_id(), for_.def_id());
394 ret.push(clean::Item {
395 inner: clean::ImplItem(clean::Impl {
396 unsafety: hir::Unsafety::Normal,
398 provided_trait_methods: provided,
402 polarity: Some(polarity.clean(cx)),
406 source: tcx.def_span(did).clean(cx),
409 visibility: clean::Inherited,
410 stability: tcx.lookup_stability(did).clean(cx),
411 deprecation: tcx.lookup_deprecation(did).clean(cx),
416 fn build_module(cx: &DocContext<'_>, did: DefId, visited: &mut FxHashSet<DefId>) -> clean::Module {
417 let mut items = Vec::new();
418 fill_in(cx, did, &mut items, visited);
419 return clean::Module { items, is_crate: false };
424 items: &mut Vec<clean::Item>,
425 visited: &mut FxHashSet<DefId>,
427 // If we're re-exporting a re-export it may actually re-export something in
428 // two namespaces, so the target may be listed twice. Make sure we only
429 // visit each node at most once.
430 for &item in cx.tcx.item_children(did).iter() {
431 let def_id = item.res.def_id();
432 if item.vis == ty::Visibility::Public {
433 if did == def_id || !visited.insert(def_id) {
436 if let Some(i) = try_inline(cx, item.res, item.ident.name, None, visited) {
444 pub fn print_inlined_const(cx: &DocContext<'_>, did: DefId) -> String {
445 if let Some(node_id) = cx.tcx.hir().as_local_hir_id(did) {
446 cx.tcx.hir().hir_to_pretty_string(node_id)
448 cx.tcx.rendered_const(did)
452 fn build_const(cx: &DocContext<'_>, did: DefId) -> clean::Constant {
454 type_: cx.tcx.type_of(did).clean(cx),
455 expr: print_inlined_const(cx, did),
456 value: clean::utils::print_evaluated_const(cx, did),
460 .as_local_hir_id(did)
461 .map_or(false, |hir_id| clean::utils::is_literal_expr(cx, hir_id)),
465 fn build_static(cx: &DocContext<'_>, did: DefId, mutable: bool) -> clean::Static {
467 type_: cx.tcx.type_of(did).clean(cx),
468 mutability: if mutable { Mutability::Mut } else { Mutability::Not },
469 expr: "\n\n\n".to_string(), // trigger the "[definition]" links
473 fn build_macro(cx: &DocContext<'_>, did: DefId, name: ast::Name) -> clean::ItemEnum {
474 let imported_from = cx.tcx.original_crate_name(did.krate);
475 match cx.enter_resolver(|r| r.cstore().load_macro_untracked(did, cx.sess())) {
476 LoadedMacro::MacroDef(def, _) => {
477 let matchers: Vec<Span> = if let ast::ItemKind::MacroDef(ref def) = def.kind {
478 let tts: Vec<_> = def.body.inner_tokens().into_trees().collect();
479 tts.chunks(4).map(|arm| arm[0].span()).collect()
484 let source = format!(
485 "macro_rules! {} {{\n{}}}",
489 .map(|span| { format!(" {} => {{ ... }};\n", span.to_src(cx)) })
493 clean::MacroItem(clean::Macro { source, imported_from: Some(imported_from).clean(cx) })
495 LoadedMacro::ProcMacro(ext) => clean::ProcMacroItem(clean::ProcMacro {
496 kind: ext.macro_kind(),
497 helpers: ext.helper_attrs.clean(cx),
502 /// A trait's generics clause actually contains all of the predicates for all of
503 /// its associated types as well. We specifically move these clauses to the
504 /// associated types instead when displaying, so when we're generating the
505 /// generics for the trait itself we need to be sure to remove them.
506 /// We also need to remove the implied "recursive" Self: Trait bound.
508 /// The inverse of this filtering logic can be found in the `Clean`
509 /// implementation for `AssociatedType`
510 fn filter_non_trait_generics(trait_did: DefId, mut g: clean::Generics) -> clean::Generics {
511 for pred in &mut g.where_predicates {
513 clean::WherePredicate::BoundPredicate { ty: clean::Generic(ref s), ref mut bounds }
516 bounds.retain(|bound| match *bound {
517 clean::GenericBound::TraitBound(
518 clean::PolyTrait { trait_: clean::ResolvedPath { did, .. }, .. },
520 ) => did != trait_did,
528 g.where_predicates.retain(|pred| match *pred {
529 clean::WherePredicate::BoundPredicate {
532 self_type: box clean::Generic(ref s),
533 trait_: box clean::ResolvedPath { did, .. },
537 } => !(*s == "Self" && did == trait_did) && !bounds.is_empty(),
543 /// Supertrait bounds for a trait are also listed in the generics coming from
544 /// the metadata for a crate, so we want to separate those out and create a new
545 /// list of explicit supertrait bounds to render nicely.
546 fn separate_supertrait_bounds(
547 mut g: clean::Generics,
548 ) -> (clean::Generics, Vec<clean::GenericBound>) {
549 let mut ty_bounds = Vec::new();
550 g.where_predicates.retain(|pred| match *pred {
551 clean::WherePredicate::BoundPredicate { ty: clean::Generic(ref s), ref bounds }
554 ty_bounds.extend(bounds.iter().cloned());
562 pub fn record_extern_trait(cx: &DocContext<'_>, did: DefId) {
568 if cx.external_traits.borrow().contains_key(&did)
569 || cx.active_extern_traits.borrow().contains(&did)
575 cx.active_extern_traits.borrow_mut().insert(did);
577 debug!("record_extern_trait: {:?}", did);
578 let trait_ = build_external_trait(cx, did);
580 cx.external_traits.borrow_mut().insert(did, trait_);
581 cx.active_extern_traits.borrow_mut().remove(&did);