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a2a8927a XL |
1 | //! Collects trait impls for each item in the crate. For example, if a crate |
2 | //! defines a struct that implements a trait, this pass will note that the | |
3 | //! struct implements that trait. | |
60c5eb7d | 4 | use super::Pass; |
9fa01778 XL |
5 | use crate::clean::*; |
6 | use crate::core::DocContext; | |
5099ac24 | 7 | use crate::formats::cache::Cache; |
3c0e092e | 8 | use crate::visit::DocVisitor; |
0bf4aa26 | 9 | |
3c0e092e XL |
10 | use rustc_data_structures::fx::{FxHashMap, FxHashSet}; |
11 | use rustc_hir::def_id::DefId; | |
923072b8 | 12 | use rustc_middle::ty::{self, DefIdTree}; |
dfeec247 | 13 | use rustc_span::symbol::sym; |
0bf4aa26 | 14 | |
923072b8 | 15 | pub(crate) const COLLECT_TRAIT_IMPLS: Pass = Pass { |
532ac7d7 | 16 | name: "collect-trait-impls", |
60c5eb7d | 17 | run: collect_trait_impls, |
532ac7d7 XL |
18 | description: "retrieves trait impls for items in the crate", |
19 | }; | |
0bf4aa26 | 20 | |
923072b8 | 21 | pub(crate) fn collect_trait_impls(mut krate: Crate, cx: &mut DocContext<'_>) -> Crate { |
3c0e092e | 22 | let synth_impls = cx.sess().time("collect_synthetic_impls", || { |
6a06907d | 23 | let mut synth = SyntheticImplCollector { cx, impls: Vec::new() }; |
3c0e092e XL |
24 | synth.visit_crate(&krate); |
25 | synth.impls | |
6a06907d | 26 | }); |
0bf4aa26 | 27 | |
60c5eb7d | 28 | let prims: FxHashSet<PrimitiveType> = krate.primitives.iter().map(|p| p.1).collect(); |
0bf4aa26 XL |
29 | |
30 | let crate_items = { | |
31 | let mut coll = ItemCollector::new(); | |
3c0e092e | 32 | cx.sess().time("collect_items_for_trait_impls", || coll.visit_crate(&krate)); |
0bf4aa26 XL |
33 | coll.items |
34 | }; | |
35 | ||
04454e1e FG |
36 | let mut new_items_external = Vec::new(); |
37 | let mut new_items_local = Vec::new(); | |
0bf4aa26 | 38 | |
5099ac24 FG |
39 | // External trait impls. |
40 | cx.with_all_trait_impls(|cx, all_trait_impls| { | |
41 | let _prof_timer = cx.tcx.sess.prof.generic_activity("build_extern_trait_impls"); | |
42 | for &impl_def_id in all_trait_impls.iter().skip_while(|def_id| def_id.is_local()) { | |
04454e1e FG |
43 | inline::build_impl(cx, None, impl_def_id, None, &mut new_items_external); |
44 | } | |
45 | }); | |
46 | ||
47 | // Local trait impls. | |
48 | cx.with_all_trait_impls(|cx, all_trait_impls| { | |
49 | let _prof_timer = cx.tcx.sess.prof.generic_activity("build_local_trait_impls"); | |
50 | let mut attr_buf = Vec::new(); | |
51 | for &impl_def_id in all_trait_impls.iter().take_while(|def_id| def_id.is_local()) { | |
52 | let mut parent = Some(cx.tcx.parent(impl_def_id)); | |
53 | while let Some(did) = parent { | |
54 | attr_buf.extend( | |
55 | cx.tcx | |
56 | .get_attrs(did, sym::doc) | |
57 | .filter(|attr| { | |
58 | if let Some([attr]) = attr.meta_item_list().as_deref() { | |
59 | attr.has_name(sym::cfg) | |
60 | } else { | |
61 | false | |
62 | } | |
63 | }) | |
64 | .cloned(), | |
65 | ); | |
66 | parent = cx.tcx.opt_parent(did); | |
67 | } | |
68 | inline::build_impl(cx, None, impl_def_id, Some(&attr_buf), &mut new_items_local); | |
69 | attr_buf.clear(); | |
0bf4aa26 | 70 | } |
5099ac24 | 71 | }); |
0bf4aa26 | 72 | |
5099ac24 | 73 | cx.tcx.sess.prof.generic_activity("build_primitive_trait_impls").run(|| { |
5e7ed085 | 74 | for def_id in PrimitiveType::all_impls(cx.tcx) { |
04454e1e | 75 | // Try to inline primitive impls from other crates. |
5099ac24 | 76 | if !def_id.is_local() { |
04454e1e FG |
77 | inline::build_impl(cx, None, def_id, None, &mut new_items_external); |
78 | } | |
79 | } | |
80 | for (prim, did) in PrimitiveType::primitive_locations(cx.tcx) { | |
81 | // Do not calculate blanket impl list for docs that are not going to be rendered. | |
82 | // While the `impl` blocks themselves are only in `libcore`, the module with `doc` | |
83 | // attached is directly included in `libstd` as well. | |
923072b8 | 84 | let tcx = cx.tcx; |
04454e1e | 85 | if did.is_local() { |
923072b8 FG |
86 | for def_id in prim.impls(tcx).filter(|def_id| { |
87 | // Avoid including impl blocks with filled-in generics. | |
88 | // https://github.com/rust-lang/rust/issues/94937 | |
89 | // | |
90 | // FIXME(notriddle): https://github.com/rust-lang/rust/issues/97129 | |
91 | // | |
92 | // This tactic of using inherent impl blocks for getting | |
93 | // auto traits and blanket impls is a hack. What we really | |
94 | // want is to check if `[T]` impls `Send`, which has | |
95 | // nothing to do with the inherent impl. | |
96 | // | |
97 | // Rustdoc currently uses these `impl` block as a source of | |
98 | // the `Ty`, as well as the `ParamEnv`, `SubstsRef`, and | |
99 | // `Generics`. To avoid relying on the `impl` block, these | |
100 | // things would need to be created from wholecloth, in a | |
101 | // form that is valid for use in type inference. | |
102 | let ty = tcx.type_of(def_id); | |
103 | match ty.kind() { | |
104 | ty::Slice(ty) | |
105 | | ty::Ref(_, ty, _) | |
106 | | ty::RawPtr(ty::TypeAndMut { ty, .. }) => { | |
107 | matches!(ty.kind(), ty::Param(..)) | |
108 | } | |
109 | ty::Tuple(tys) => tys.iter().all(|ty| matches!(ty.kind(), ty::Param(..))), | |
110 | _ => true, | |
111 | } | |
112 | }) { | |
94222f64 | 113 | let impls = get_auto_trait_and_blanket_impls(cx, def_id); |
04454e1e | 114 | new_items_external.extend(impls.filter(|i| cx.inlined.insert(i.item_id))); |
fc512014 | 115 | } |
5099ac24 | 116 | } |
0bf4aa26 | 117 | } |
5099ac24 | 118 | }); |
0bf4aa26 | 119 | |
5099ac24 | 120 | let mut cleaner = BadImplStripper { prims, items: crate_items, cache: &cx.cache }; |
3c0e092e XL |
121 | let mut type_did_to_deref_target: FxHashMap<DefId, &Type> = FxHashMap::default(); |
122 | ||
123 | // Follow all `Deref` targets of included items and recursively add them as valid | |
124 | fn add_deref_target( | |
125 | cx: &DocContext<'_>, | |
126 | map: &FxHashMap<DefId, &Type>, | |
5099ac24 | 127 | cleaner: &mut BadImplStripper<'_>, |
04454e1e | 128 | targets: &mut FxHashSet<DefId>, |
3c0e092e XL |
129 | type_did: DefId, |
130 | ) { | |
131 | if let Some(target) = map.get(&type_did) { | |
132 | debug!("add_deref_target: type {:?}, target {:?}", type_did, target); | |
133 | if let Some(target_prim) = target.primitive_type() { | |
134 | cleaner.prims.insert(target_prim); | |
135 | } else if let Some(target_did) = target.def_id(&cx.cache) { | |
136 | // `impl Deref<Target = S> for S` | |
04454e1e | 137 | if !targets.insert(target_did) { |
3c0e092e XL |
138 | // Avoid infinite cycles |
139 | return; | |
140 | } | |
141 | cleaner.items.insert(target_did.into()); | |
04454e1e | 142 | add_deref_target(cx, map, cleaner, targets, target_did); |
3c0e092e XL |
143 | } |
144 | } | |
145 | } | |
36d6ef2b XL |
146 | |
147 | // scan through included items ahead of time to splice in Deref targets to the "valid" sets | |
04454e1e | 148 | for it in new_items_external.iter().chain(new_items_local.iter()) { |
36d6ef2b | 149 | if let ImplItem(Impl { ref for_, ref trait_, ref items, .. }) = *it.kind { |
3c0e092e XL |
150 | if trait_.as_ref().map(|t| t.def_id()) == cx.tcx.lang_items().deref_trait() |
151 | && cleaner.keep_impl(for_, true) | |
c295e0f8 | 152 | { |
36d6ef2b XL |
153 | let target = items |
154 | .iter() | |
155 | .find_map(|item| match *item.kind { | |
04454e1e | 156 | AssocTypeItem(ref t, _) => Some(&t.type_), |
36d6ef2b XL |
157 | _ => None, |
158 | }) | |
159 | .expect("Deref impl without Target type"); | |
160 | ||
161 | if let Some(prim) = target.primitive_type() { | |
162 | cleaner.prims.insert(prim); | |
3c0e092e | 163 | } else if let Some(did) = target.def_id(&cx.cache) { |
17df50a5 | 164 | cleaner.items.insert(did.into()); |
36d6ef2b | 165 | } |
5099ac24 | 166 | if let Some(for_did) = for_.def_id(&cx.cache) { |
3c0e092e XL |
167 | if type_did_to_deref_target.insert(for_did, target).is_none() { |
168 | // Since only the `DefId` portion of the `Type` instances is known to be same for both the | |
169 | // `Deref` target type and the impl for type positions, this map of types is keyed by | |
170 | // `DefId` and for convenience uses a special cleaner that accepts `DefId`s directly. | |
171 | if cleaner.keep_impl_with_def_id(for_did.into()) { | |
04454e1e FG |
172 | let mut targets = FxHashSet::default(); |
173 | targets.insert(for_did); | |
174 | add_deref_target( | |
175 | cx, | |
176 | &type_did_to_deref_target, | |
177 | &mut cleaner, | |
178 | &mut targets, | |
179 | for_did, | |
180 | ); | |
3c0e092e XL |
181 | } |
182 | } | |
183 | } | |
36d6ef2b XL |
184 | } |
185 | } | |
186 | } | |
187 | ||
04454e1e FG |
188 | // Filter out external items that are not needed |
189 | new_items_external.retain(|it| { | |
3c0e092e XL |
190 | if let ImplItem(Impl { ref for_, ref trait_, ref kind, .. }) = *it.kind { |
191 | cleaner.keep_impl( | |
192 | for_, | |
193 | trait_.as_ref().map(|t| t.def_id()) == cx.tcx.lang_items().deref_trait(), | |
194 | ) || trait_.as_ref().map_or(false, |t| cleaner.keep_impl_with_def_id(t.def_id().into())) | |
195 | || kind.is_blanket() | |
36d6ef2b XL |
196 | } else { |
197 | true | |
198 | } | |
199 | }); | |
200 | ||
3c0e092e XL |
201 | if let ModuleItem(Module { items, .. }) = &mut *krate.module.kind { |
202 | items.extend(synth_impls); | |
04454e1e FG |
203 | items.extend(new_items_external); |
204 | items.extend(new_items_local); | |
0bf4aa26 XL |
205 | } else { |
206 | panic!("collect-trait-impls can't run"); | |
5869c6ff XL |
207 | }; |
208 | ||
0bf4aa26 XL |
209 | krate |
210 | } | |
211 | ||
532ac7d7 | 212 | struct SyntheticImplCollector<'a, 'tcx> { |
6a06907d | 213 | cx: &'a mut DocContext<'tcx>, |
0bf4aa26 XL |
214 | impls: Vec<Item>, |
215 | } | |
216 | ||
3c0e092e XL |
217 | impl<'a, 'tcx> DocVisitor for SyntheticImplCollector<'a, 'tcx> { |
218 | fn visit_item(&mut self, i: &Item) { | |
0bf4aa26 | 219 | if i.is_struct() || i.is_enum() || i.is_union() { |
48663c56 | 220 | // FIXME(eddyb) is this `doc(hidden)` check needed? |
04454e1e | 221 | if !self.cx.tcx.is_doc_hidden(i.item_id.expect_def_id()) { |
17df50a5 | 222 | self.impls |
04454e1e | 223 | .extend(get_auto_trait_and_blanket_impls(self.cx, i.item_id.expect_def_id())); |
0bf4aa26 XL |
224 | } |
225 | } | |
226 | ||
3c0e092e | 227 | self.visit_item_recur(i) |
0bf4aa26 XL |
228 | } |
229 | } | |
230 | ||
231 | #[derive(Default)] | |
232 | struct ItemCollector { | |
136023e0 | 233 | items: FxHashSet<ItemId>, |
0bf4aa26 XL |
234 | } |
235 | ||
236 | impl ItemCollector { | |
237 | fn new() -> Self { | |
238 | Self::default() | |
239 | } | |
240 | } | |
241 | ||
3c0e092e XL |
242 | impl DocVisitor for ItemCollector { |
243 | fn visit_item(&mut self, i: &Item) { | |
04454e1e | 244 | self.items.insert(i.item_id); |
0bf4aa26 | 245 | |
3c0e092e | 246 | self.visit_item_recur(i) |
0bf4aa26 XL |
247 | } |
248 | } | |
249 | ||
5099ac24 | 250 | struct BadImplStripper<'a> { |
0bf4aa26 | 251 | prims: FxHashSet<PrimitiveType>, |
136023e0 | 252 | items: FxHashSet<ItemId>, |
5099ac24 | 253 | cache: &'a Cache, |
0bf4aa26 XL |
254 | } |
255 | ||
5099ac24 | 256 | impl<'a> BadImplStripper<'a> { |
3c0e092e | 257 | fn keep_impl(&self, ty: &Type, is_deref: bool) -> bool { |
0bf4aa26 XL |
258 | if let Generic(_) = ty { |
259 | // keep impls made on generics | |
260 | true | |
261 | } else if let Some(prim) = ty.primitive_type() { | |
262 | self.prims.contains(&prim) | |
5099ac24 | 263 | } else if let Some(did) = ty.def_id(self.cache) { |
3c0e092e | 264 | is_deref || self.keep_impl_with_def_id(did.into()) |
0bf4aa26 XL |
265 | } else { |
266 | false | |
267 | } | |
268 | } | |
17df50a5 | 269 | |
04454e1e FG |
270 | fn keep_impl_with_def_id(&self, item_id: ItemId) -> bool { |
271 | self.items.contains(&item_id) | |
17df50a5 | 272 | } |
0bf4aa26 | 273 | } |