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_mir::const_eval::is_min_const_fn;
13 use rustc_span::hygiene::MacroKind;
14 use rustc_span::symbol::sym;
18 use crate::clean::{self, GetDefId, ToSource, TypeKind};
19 use crate::core::DocContext;
24 type Attrs<'hir> = rustc::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.
42 attrs: Option<Attrs<'_>>,
43 visited: &mut FxHashSet<DefId>,
44 ) -> Option<Vec<clean::Item>> {
45 let did = if let Some(did) = res.opt_def_id() {
53 let mut ret = Vec::new();
55 let attrs_clone = attrs.clone();
57 let inner = match res {
58 Res::Def(DefKind::Trait, did) => {
59 record_extern_fqn(cx, did, clean::TypeKind::Trait);
60 ret.extend(build_impls(cx, did, attrs));
61 clean::TraitItem(build_external_trait(cx, did))
63 Res::Def(DefKind::Fn, did) => {
64 record_extern_fqn(cx, did, clean::TypeKind::Function);
65 clean::FunctionItem(build_external_function(cx, did))
67 Res::Def(DefKind::Struct, did) => {
68 record_extern_fqn(cx, did, clean::TypeKind::Struct);
69 ret.extend(build_impls(cx, did, attrs));
70 clean::StructItem(build_struct(cx, did))
72 Res::Def(DefKind::Union, did) => {
73 record_extern_fqn(cx, did, clean::TypeKind::Union);
74 ret.extend(build_impls(cx, did, attrs));
75 clean::UnionItem(build_union(cx, did))
77 Res::Def(DefKind::TyAlias, did) => {
78 record_extern_fqn(cx, did, clean::TypeKind::Typedef);
79 ret.extend(build_impls(cx, did, attrs));
80 clean::TypedefItem(build_type_alias(cx, did), false)
82 Res::Def(DefKind::Enum, did) => {
83 record_extern_fqn(cx, did, clean::TypeKind::Enum);
84 ret.extend(build_impls(cx, did, attrs));
85 clean::EnumItem(build_enum(cx, did))
87 Res::Def(DefKind::ForeignTy, did) => {
88 record_extern_fqn(cx, did, clean::TypeKind::Foreign);
89 ret.extend(build_impls(cx, did, attrs));
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, clean::TypeKind::Module);
99 clean::ModuleItem(build_module(cx, did, visited))
101 Res::Def(DefKind::Static, did) => {
102 record_extern_fqn(cx, did, clean::TypeKind::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, clean::TypeKind::Const);
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 => TypeKind::Macro,
114 MacroKind::Attr => TypeKind::Attr,
115 MacroKind::Derive => TypeKind::Derive,
117 record_extern_fqn(cx, did, type_kind);
123 let target_attrs = load_attrs(cx, did);
124 let attrs = merge_attrs(cx, target_attrs, attrs_clone);
126 cx.renderinfo.borrow_mut().inlined.insert(did);
127 ret.push(clean::Item {
128 source: cx.tcx.def_span(did).clean(cx),
129 name: Some(name.clean(cx)),
132 visibility: clean::Public,
133 stability: cx.tcx.lookup_stability(did).clean(cx),
134 deprecation: cx.tcx.lookup_deprecation(did).clean(cx),
140 pub fn try_inline_glob(
143 visited: &mut FxHashSet<DefId>,
144 ) -> Option<Vec<clean::Item>> {
148 let did = res.def_id();
154 Res::Def(DefKind::Mod, did) => {
155 let m = build_module(cx, did, visited);
158 // glob imports on things like enums aren't inlined even for local exports, so just bail
163 pub fn load_attrs<'hir>(cx: &DocContext<'hir>, did: DefId) -> Attrs<'hir> {
164 cx.tcx.get_attrs(did)
167 /// Record an external fully qualified name in the external_paths cache.
169 /// These names are used later on by HTML rendering to generate things like
170 /// source links back to the original item.
171 pub fn record_extern_fqn(cx: &DocContext<'_>, did: DefId, kind: clean::TypeKind) {
172 let crate_name = cx.tcx.crate_name(did.krate).to_string();
174 let relative = cx.tcx.def_path(did).data.into_iter().filter_map(|elem| {
175 // extern blocks have an empty name
176 let s = elem.data.to_string();
177 if !s.is_empty() { Some(s) } else { None }
179 let fqn = if let clean::TypeKind::Macro = kind {
180 vec![crate_name, relative.last().expect("relative was empty")]
182 once(crate_name).chain(relative).collect()
186 cx.renderinfo.borrow_mut().exact_paths.insert(did, fqn);
188 cx.renderinfo.borrow_mut().external_paths.insert(did, (fqn, kind));
192 pub fn build_external_trait(cx: &DocContext<'_>, did: DefId) -> clean::Trait {
193 let auto_trait = cx.tcx.trait_def(did).has_auto_impl;
194 let trait_items = cx.tcx.associated_items(did).map(|item| item.clean(cx)).collect();
195 let predicates = cx.tcx.predicates_of(did);
196 let generics = (cx.tcx.generics_of(did), predicates).clean(cx);
197 let generics = filter_non_trait_generics(did, generics);
198 let (generics, supertrait_bounds) = separate_supertrait_bounds(generics);
199 let is_spotlight = load_attrs(cx, did).clean(cx).has_doc_flag(sym::spotlight);
200 let is_auto = cx.tcx.trait_is_auto(did);
203 unsafety: cx.tcx.trait_def(did).unsafety,
206 bounds: supertrait_bounds,
212 fn build_external_function(cx: &DocContext<'_>, did: DefId) -> clean::Function {
213 let sig = cx.tcx.fn_sig(did);
216 if is_min_const_fn(cx.tcx, did) { hir::Constness::Const } else { hir::Constness::NotConst };
217 let asyncness = cx.tcx.asyncness(did);
218 let predicates = cx.tcx.predicates_of(did);
219 let (generics, decl) = clean::enter_impl_trait(cx, || {
220 ((cx.tcx.generics_of(did), predicates).clean(cx), (did, sig).clean(cx))
222 let (all_types, ret_types) = clean::get_all_types(&generics, &decl, cx);
226 header: hir::FnHeader { unsafety: sig.unsafety(), abi: sig.abi(), constness, asyncness },
232 fn build_enum(cx: &DocContext<'_>, did: DefId) -> clean::Enum {
233 let predicates = cx.tcx.explicit_predicates_of(did);
236 generics: (cx.tcx.generics_of(did), predicates).clean(cx),
237 variants_stripped: false,
238 variants: cx.tcx.adt_def(did).variants.clean(cx),
242 fn build_struct(cx: &DocContext<'_>, did: DefId) -> clean::Struct {
243 let predicates = cx.tcx.explicit_predicates_of(did);
244 let variant = cx.tcx.adt_def(did).non_enum_variant();
247 struct_type: match variant.ctor_kind {
248 CtorKind::Fictive => doctree::Plain,
249 CtorKind::Fn => doctree::Tuple,
250 CtorKind::Const => doctree::Unit,
252 generics: (cx.tcx.generics_of(did), predicates).clean(cx),
253 fields: variant.fields.clean(cx),
254 fields_stripped: false,
258 fn build_union(cx: &DocContext<'_>, did: DefId) -> clean::Union {
259 let predicates = cx.tcx.explicit_predicates_of(did);
260 let variant = cx.tcx.adt_def(did).non_enum_variant();
263 struct_type: doctree::Plain,
264 generics: (cx.tcx.generics_of(did), predicates).clean(cx),
265 fields: variant.fields.clean(cx),
266 fields_stripped: false,
270 fn build_type_alias(cx: &DocContext<'_>, did: DefId) -> clean::Typedef {
271 let predicates = cx.tcx.explicit_predicates_of(did);
274 type_: cx.tcx.type_of(did).clean(cx),
275 generics: (cx.tcx.generics_of(did), predicates).clean(cx),
276 item_type: build_type_alias_type(cx, did),
280 fn build_type_alias_type(cx: &DocContext<'_>, did: DefId) -> Option<clean::Type> {
281 let type_ = cx.tcx.type_of(did).clean(cx);
282 type_.def_id().and_then(|did| build_ty(cx, did))
285 pub fn build_ty(cx: &DocContext, did: DefId) -> Option<clean::Type> {
286 match cx.tcx.def_kind(did)? {
287 DefKind::Struct | DefKind::Union | DefKind::Enum | DefKind::Const | DefKind::Static => {
288 Some(cx.tcx.type_of(did).clean(cx))
290 DefKind::TyAlias => build_type_alias_type(cx, did),
295 pub fn build_impls(cx: &DocContext<'_>, did: DefId, attrs: Option<Attrs<'_>>) -> Vec<clean::Item> {
297 let mut impls = Vec::new();
299 for &did in tcx.inherent_impls(did).iter() {
300 build_impl(cx, did, attrs.clone(), &mut impls);
309 other_attrs: Option<Attrs<'_>>,
310 ) -> clean::Attributes {
311 let mut merged_attrs: Vec<ast::Attribute> = Vec::with_capacity(attrs.len());
312 // If we have additional attributes (from a re-export),
313 // always insert them first. This ensure that re-export
314 // doc comments show up before the original doc comments
315 // when we render them.
316 if let Some(a) = other_attrs {
317 merged_attrs.extend(a.iter().cloned());
319 merged_attrs.extend(attrs.to_vec());
320 merged_attrs.clean(cx)
326 attrs: Option<Attrs<'_>>,
327 ret: &mut Vec<clean::Item>,
329 if !cx.renderinfo.borrow_mut().inlined.insert(did) {
333 let attrs = merge_attrs(cx, load_attrs(cx, did), attrs);
336 let associated_trait = tcx.impl_trait_ref(did);
338 // Only inline impl if the implemented trait is
339 // reachable in rustdoc generated documentation
341 if let Some(traitref) = associated_trait {
342 if !cx.renderinfo.borrow().access_levels.is_public(traitref.def_id) {
348 let for_ = if let Some(hir_id) = tcx.hir().as_local_hir_id(did) {
349 match tcx.hir().expect_item(hir_id).kind {
350 hir::ItemKind::Impl(.., ref t, _) => t.clean(cx),
351 _ => panic!("did given to build_impl was not an impl"),
354 tcx.type_of(did).clean(cx)
357 // Only inline impl if the implementing type is
358 // reachable in rustdoc generated documentation
360 if let Some(did) = for_.def_id() {
361 if !cx.renderinfo.borrow().access_levels.is_public(did) {
367 let predicates = tcx.explicit_predicates_of(did);
368 let (trait_items, generics) = if let Some(hir_id) = tcx.hir().as_local_hir_id(did) {
369 match tcx.hir().expect_item(hir_id).kind {
370 hir::ItemKind::Impl(.., ref gen, _, _, ref item_ids) => (
371 item_ids.iter().map(|ii| tcx.hir().impl_item(ii.id).clean(cx)).collect::<Vec<_>>(),
374 _ => panic!("did given to build_impl was not an impl"),
378 tcx.associated_items(did)
380 if associated_trait.is_some() || item.vis == ty::Visibility::Public {
386 .collect::<Vec<_>>(),
387 clean::enter_impl_trait(cx, || (tcx.generics_of(did), predicates).clean(cx)),
390 let polarity = tcx.impl_polarity(did);
391 let trait_ = associated_trait.clean(cx).map(|bound| match bound {
392 clean::GenericBound::TraitBound(polyt, _) => polyt.trait_,
393 clean::GenericBound::Outlives(..) => unreachable!(),
395 if trait_.def_id() == tcx.lang_items().deref_trait() {
396 super::build_deref_target_impls(cx, &trait_items, ret);
398 if let Some(trait_did) = trait_.def_id() {
399 record_extern_trait(cx, trait_did);
402 let provided = trait_
405 tcx.provided_trait_methods(did).into_iter().map(|meth| meth.ident.to_string()).collect()
407 .unwrap_or_default();
409 debug!("build_impl: impl {:?} for {:?}", trait_.def_id(), for_.def_id());
411 ret.push(clean::Item {
412 inner: clean::ImplItem(clean::Impl {
413 unsafety: hir::Unsafety::Normal,
415 provided_trait_methods: provided,
419 polarity: Some(polarity.clean(cx)),
423 source: tcx.def_span(did).clean(cx),
426 visibility: clean::Inherited,
427 stability: tcx.lookup_stability(did).clean(cx),
428 deprecation: tcx.lookup_deprecation(did).clean(cx),
433 fn build_module(cx: &DocContext<'_>, did: DefId, visited: &mut FxHashSet<DefId>) -> clean::Module {
434 let mut items = Vec::new();
435 fill_in(cx, did, &mut items, visited);
436 return clean::Module { items, is_crate: false };
441 items: &mut Vec<clean::Item>,
442 visited: &mut FxHashSet<DefId>,
444 // If we're re-exporting a re-export it may actually re-export something in
445 // two namespaces, so the target may be listed twice. Make sure we only
446 // visit each node at most once.
447 for &item in cx.tcx.item_children(did).iter() {
448 let def_id = item.res.def_id();
449 if item.vis == ty::Visibility::Public {
450 if did == def_id || !visited.insert(def_id) {
453 if let Some(i) = try_inline(cx, item.res, item.ident.name, None, visited) {
461 pub fn print_inlined_const(cx: &DocContext<'_>, did: DefId) -> String {
462 if let Some(node_id) = cx.tcx.hir().as_local_hir_id(did) {
463 cx.tcx.hir().hir_to_pretty_string(node_id)
465 cx.tcx.rendered_const(did)
469 fn build_const(cx: &DocContext<'_>, did: DefId) -> clean::Constant {
471 type_: cx.tcx.type_of(did).clean(cx),
472 expr: print_inlined_const(cx, did),
473 value: clean::utils::print_evaluated_const(cx, did),
477 .as_local_hir_id(did)
478 .map_or(false, |hir_id| clean::utils::is_literal_expr(cx, hir_id)),
482 fn build_static(cx: &DocContext<'_>, did: DefId, mutable: bool) -> clean::Static {
484 type_: cx.tcx.type_of(did).clean(cx),
485 mutability: if mutable { Mutability::Mut } else { Mutability::Not },
486 expr: "\n\n\n".to_string(), // trigger the "[definition]" links
490 fn build_macro(cx: &DocContext<'_>, did: DefId, name: ast::Name) -> clean::ItemEnum {
491 let imported_from = cx.tcx.original_crate_name(did.krate);
492 match cx.enter_resolver(|r| r.cstore().load_macro_untracked(did, cx.sess())) {
493 LoadedMacro::MacroDef(def, _) => {
494 let matchers: Vec<Span> = if let ast::ItemKind::MacroDef(ref def) = def.kind {
495 let tts: Vec<_> = def.body.inner_tokens().into_trees().collect();
496 tts.chunks(4).map(|arm| arm[0].span()).collect()
501 let source = format!(
502 "macro_rules! {} {{\n{}}}",
506 .map(|span| { format!(" {} => {{ ... }};\n", span.to_src(cx)) })
510 clean::MacroItem(clean::Macro { source, imported_from: Some(imported_from).clean(cx) })
512 LoadedMacro::ProcMacro(ext) => clean::ProcMacroItem(clean::ProcMacro {
513 kind: ext.macro_kind(),
514 helpers: ext.helper_attrs.clean(cx),
519 /// A trait's generics clause actually contains all of the predicates for all of
520 /// its associated types as well. We specifically move these clauses to the
521 /// associated types instead when displaying, so when we're generating the
522 /// generics for the trait itself we need to be sure to remove them.
523 /// We also need to remove the implied "recursive" Self: Trait bound.
525 /// The inverse of this filtering logic can be found in the `Clean`
526 /// implementation for `AssociatedType`
527 fn filter_non_trait_generics(trait_did: DefId, mut g: clean::Generics) -> clean::Generics {
528 for pred in &mut g.where_predicates {
530 clean::WherePredicate::BoundPredicate { ty: clean::Generic(ref s), ref mut bounds }
533 bounds.retain(|bound| match *bound {
534 clean::GenericBound::TraitBound(
535 clean::PolyTrait { trait_: clean::ResolvedPath { did, .. }, .. },
537 ) => did != trait_did,
545 g.where_predicates.retain(|pred| match *pred {
546 clean::WherePredicate::BoundPredicate {
549 self_type: box clean::Generic(ref s),
550 trait_: box clean::ResolvedPath { did, .. },
554 } => !(*s == "Self" && did == trait_did) && !bounds.is_empty(),
560 /// Supertrait bounds for a trait are also listed in the generics coming from
561 /// the metadata for a crate, so we want to separate those out and create a new
562 /// list of explicit supertrait bounds to render nicely.
563 fn separate_supertrait_bounds(
564 mut g: clean::Generics,
565 ) -> (clean::Generics, Vec<clean::GenericBound>) {
566 let mut ty_bounds = Vec::new();
567 g.where_predicates.retain(|pred| match *pred {
568 clean::WherePredicate::BoundPredicate { ty: clean::Generic(ref s), ref bounds }
571 ty_bounds.extend(bounds.iter().cloned());
579 pub fn record_extern_trait(cx: &DocContext<'_>, did: DefId) {
585 if cx.external_traits.borrow().contains_key(&did)
586 || cx.active_extern_traits.borrow().contains(&did)
592 cx.active_extern_traits.borrow_mut().insert(did);
594 debug!("record_extern_trait: {:?}", did);
595 let trait_ = build_external_trait(cx, did);
597 cx.external_traits.borrow_mut().insert(did, trait_);
598 cx.active_extern_traits.borrow_mut().remove(&did);