3 use crate::core::DocContext;
4 use crate::fold::DocFolder;
6 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
7 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
8 use rustc_middle::ty::DefIdTree;
9 use rustc_span::symbol::sym;
11 crate const COLLECT_TRAIT_IMPLS: Pass = Pass {
12 name: "collect-trait-impls",
13 run: collect_trait_impls,
14 description: "retrieves trait impls for items in the crate",
17 crate fn collect_trait_impls(krate: Crate, cx: &mut DocContext<'_>) -> Crate {
18 let (mut krate, synth_impls) = cx.sess().time("collect_synthetic_impls", || {
19 let mut synth = SyntheticImplCollector { cx, impls: Vec::new() };
20 (synth.fold_crate(krate), synth.impls)
23 let prims: FxHashSet<PrimitiveType> = krate.primitives.iter().map(|p| p.1).collect();
26 let mut coll = ItemCollector::new();
27 krate = cx.sess().time("collect_items_for_trait_impls", || coll.fold_crate(krate));
31 let mut new_items = Vec::new();
33 for &cnum in cx.tcx.crates().iter() {
34 for &(did, _) in cx.tcx.all_trait_implementations(cnum).iter() {
35 cx.tcx.sess.prof.generic_activity("build_extern_trait_impl").run(|| {
36 inline::build_impl(cx, None, did, None, &mut new_items);
41 // Also try to inline primitive impls from other crates.
42 for &def_id in PrimitiveType::all_impls(cx.tcx).values().flatten() {
43 if !def_id.is_local() {
44 cx.tcx.sess.prof.generic_activity("build_primitive_trait_impls").run(|| {
45 inline::build_impl(cx, None, def_id, None, &mut new_items);
47 // FIXME(eddyb) is this `doc(hidden)` check needed?
48 if !cx.tcx.get_attrs(def_id).lists(sym::doc).has_word(sym::hidden) {
49 let self_ty = cx.tcx.type_of(def_id);
50 let impls = get_auto_trait_and_blanket_impls(cx, self_ty, def_id);
52 new_items.extend(impls.filter(|i| cx.renderinfo.inlined.insert(i.def_id)));
58 // `tcx.crates()` doesn't include the local crate, and `tcx.all_trait_implementations`
59 // doesn't work with it anyway, so pull them from the HIR map instead
60 let mut extra_attrs = Vec::new();
61 for &trait_did in cx.tcx.all_traits(LOCAL_CRATE).iter() {
62 for &impl_did in cx.tcx.hir().trait_impls(trait_did) {
63 let impl_did = impl_did.to_def_id();
64 cx.tcx.sess.prof.generic_activity("build_local_trait_impl").run(|| {
65 let mut parent = cx.tcx.parent(impl_did);
66 while let Some(did) = parent {
71 .filter(|attr| attr.has_name(sym::doc))
73 if let Some([attr]) = attr.meta_item_list().as_deref() {
74 attr.has_name(sym::cfg)
81 parent = cx.tcx.parent(did);
83 inline::build_impl(cx, None, impl_did, Some(&extra_attrs), &mut new_items);
89 let mut cleaner = BadImplStripper { prims, items: crate_items };
91 let mut type_did_to_deref_target: FxHashMap<DefId, &Type> = FxHashMap::default();
92 // Gather all type to `Deref` target edges.
93 for it in &new_items {
94 if let ImplItem(Impl { ref for_, ref trait_, ref items, .. }) = *it.kind {
95 if trait_.def_id() == cx.tcx.lang_items().deref_trait() {
96 let target = items.iter().find_map(|item| match *item.kind {
97 TypedefItem(ref t, true) => Some(&t.type_),
100 if let (Some(for_did), Some(target)) = (for_.def_id(), target) {
101 type_did_to_deref_target.insert(for_did, target);
106 // Follow all `Deref` targets of included items and recursively add them as valid
108 map: &FxHashMap<DefId, &Type>,
109 cleaner: &mut BadImplStripper,
112 if let Some(target) = map.get(type_did) {
113 debug!("add_deref_target: type {:?}, target {:?}", type_did, target);
114 if let Some(target_prim) = target.primitive_type() {
115 cleaner.prims.insert(target_prim);
116 } else if let Some(target_did) = target.def_id() {
117 // `impl Deref<Target = S> for S`
118 if target_did == *type_did {
119 // Avoid infinite cycles
122 cleaner.items.insert(target_did);
123 add_deref_target(map, cleaner, &target_did);
127 for type_did in type_did_to_deref_target.keys() {
128 // Since only the `DefId` portion of the `Type` instances is known to be same for both the
129 // `Deref` target type and the impl for type positions, this map of types is keyed by
130 // `DefId` and for convenience uses a special cleaner that accepts `DefId`s directly.
131 if cleaner.keep_impl_with_def_id(type_did) {
132 add_deref_target(&type_did_to_deref_target, &mut cleaner, type_did);
136 let items = if let Some(ref mut it) = krate.module {
137 if let ModuleItem(Module { ref mut items, .. }) = *it.kind {
140 panic!("collect-trait-impls can't run");
143 panic!("collect-trait-impls can't run");
146 items.extend(synth_impls);
147 for it in new_items.drain(..) {
148 if let ImplItem(Impl { ref for_, ref trait_, ref blanket_impl, .. }) = *it.kind {
149 if !(cleaner.keep_impl(for_)
150 || trait_.as_ref().map_or(false, |t| cleaner.keep_impl(t))
151 || blanket_impl.is_some())
163 struct SyntheticImplCollector<'a, 'tcx> {
164 cx: &'a mut DocContext<'tcx>,
168 impl<'a, 'tcx> DocFolder for SyntheticImplCollector<'a, 'tcx> {
169 fn fold_item(&mut self, i: Item) -> Option<Item> {
170 if i.is_struct() || i.is_enum() || i.is_union() {
171 // FIXME(eddyb) is this `doc(hidden)` check needed?
172 if !self.cx.tcx.get_attrs(i.def_id).lists(sym::doc).has_word(sym::hidden) {
173 self.impls.extend(get_auto_trait_and_blanket_impls(
175 self.cx.tcx.type_of(i.def_id),
181 Some(self.fold_item_recur(i))
186 struct ItemCollector {
187 items: FxHashSet<DefId>,
196 impl DocFolder for ItemCollector {
197 fn fold_item(&mut self, i: Item) -> Option<Item> {
198 self.items.insert(i.def_id);
200 Some(self.fold_item_recur(i))
204 struct BadImplStripper {
205 prims: FxHashSet<PrimitiveType>,
206 items: FxHashSet<DefId>,
209 impl BadImplStripper {
210 fn keep_impl(&self, ty: &Type) -> bool {
211 if let Generic(_) = ty {
212 // keep impls made on generics
214 } else if let Some(prim) = ty.primitive_type() {
215 self.prims.contains(&prim)
216 } else if let Some(did) = ty.def_id() {
217 self.keep_impl_with_def_id(&did)
223 fn keep_impl_with_def_id(&self, did: &DefId) -> bool {
224 self.items.contains(did)