1 //! This module contains the "cleaned" pieces of the AST, and the functions
2 //! that clean them.
3 
4 mod auto_trait;
5 mod blanket_impl;
6 crate mod cfg;
7 crate mod inline;
8 mod simplify;
9 crate mod types;
10 crate mod utils;
11 
12 use rustc_ast as ast;
13 use rustc_attr as attr;
14 use rustc_const_eval::const_eval::is_unstable_const_fn;
15 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
16 use rustc_hir as hir;
17 use rustc_hir::def::{CtorKind, DefKind, Res};
18 use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
19 use rustc_infer::infer::region_constraints::{Constraint, RegionConstraintData};
20 use rustc_middle::middle::resolve_lifetime as rl;
21 use rustc_middle::ty::fold::TypeFolder;
22 use rustc_middle::ty::subst::{InternalSubsts, Subst};
23 use rustc_middle::ty::{self, AdtKind, DefIdTree, Lift, Ty, TyCtxt};
24 use rustc_middle::{bug, span_bug};
25 use rustc_span::hygiene::{AstPass, MacroKind};
26 use rustc_span::symbol::{kw, sym, Ident, Symbol};
27 use rustc_span::{self, ExpnKind};
28 use rustc_target::spec::abi::Abi;
29 use rustc_typeck::check::intrinsic::intrinsic_operation_unsafety;
30 use rustc_typeck::hir_ty_to_ty;
31 
32 use std::assert_matches::assert_matches;
33 use std::collections::hash_map::Entry;
34 use std::default::Default;
35 use std::hash::Hash;
36 use std::{mem, vec};
37 
38 use crate::core::{self, DocContext, ImplTraitParam};
39 use crate::formats::item_type::ItemType;
40 use crate::visit_ast::Module as DocModule;
41 
42 use utils::*;
43 
44 crate use self::types::*;
45 crate use self::utils::{get_auto_trait_and_blanket_impls, krate, register_res};
46 
47 crate trait Clean<T> {
clean(&self, cx: &mut DocContext<'_>) -> T48     fn clean(&self, cx: &mut DocContext<'_>) -> T;
49 }
50 
51 impl Clean<Item> for DocModule<'_> {
clean(&self, cx: &mut DocContext<'_>) -> Item52     fn clean(&self, cx: &mut DocContext<'_>) -> Item {
53         let mut items: Vec<Item> = vec![];
54         items.extend(self.foreigns.iter().map(|x| x.clean(cx)));
55         items.extend(self.mods.iter().map(|x| x.clean(cx)));
56         items.extend(self.items.iter().map(|x| x.clean(cx)).flatten());
57 
58         // determine if we should display the inner contents or
59         // the outer `mod` item for the source code.
60 
61         let span = Span::new({
62             let where_outer = self.where_outer(cx.tcx);
63             let sm = cx.sess().source_map();
64             let outer = sm.lookup_char_pos(where_outer.lo());
65             let inner = sm.lookup_char_pos(self.where_inner.lo());
66             if outer.file.start_pos == inner.file.start_pos {
67                 // mod foo { ... }
68                 where_outer
69             } else {
70                 // mod foo; (and a separate SourceFile for the contents)
71                 self.where_inner
72             }
73         });
74 
75         Item::from_hir_id_and_parts(
76             self.id,
77             Some(self.name),
78             ModuleItem(Module { items, span }),
79             cx,
80         )
81     }
82 }
83 
84 impl Clean<Attributes> for [ast::Attribute] {
clean(&self, _cx: &mut DocContext<'_>) -> Attributes85     fn clean(&self, _cx: &mut DocContext<'_>) -> Attributes {
86         Attributes::from_ast(self, None)
87     }
88 }
89 
90 impl Clean<GenericBound> for hir::GenericBound<'_> {
clean(&self, cx: &mut DocContext<'_>) -> GenericBound91     fn clean(&self, cx: &mut DocContext<'_>) -> GenericBound {
92         match *self {
93             hir::GenericBound::Outlives(lt) => GenericBound::Outlives(lt.clean(cx)),
94             hir::GenericBound::LangItemTrait(lang_item, span, _, generic_args) => {
95                 let def_id = cx.tcx.require_lang_item(lang_item, Some(span));
96 
97                 let trait_ref = ty::TraitRef::identity(cx.tcx, def_id).skip_binder();
98 
99                 let generic_args = generic_args.clean(cx);
100                 let bindings = match generic_args {
101                     GenericArgs::AngleBracketed { bindings, .. } => bindings,
102                     _ => bug!("clean: parenthesized `GenericBound::LangItemTrait`"),
103                 };
104 
105                 GenericBound::TraitBound(
106                     PolyTrait {
107                         trait_: (trait_ref, &bindings[..]).clean(cx),
108                         generic_params: vec![],
109                     },
110                     hir::TraitBoundModifier::None,
111                 )
112             }
113             hir::GenericBound::Trait(ref t, modifier) => {
114                 GenericBound::TraitBound(t.clean(cx), modifier)
115             }
116         }
117     }
118 }
119 
120 impl Clean<Path> for (ty::TraitRef<'_>, &[TypeBinding]) {
clean(&self, cx: &mut DocContext<'_>) -> Path121     fn clean(&self, cx: &mut DocContext<'_>) -> Path {
122         let (trait_ref, bounds) = *self;
123         let kind = cx.tcx.def_kind(trait_ref.def_id).into();
124         if !matches!(kind, ItemType::Trait | ItemType::TraitAlias) {
125             span_bug!(
126                 cx.tcx.def_span(trait_ref.def_id),
127                 "`TraitRef` had unexpected kind {:?}",
128                 kind
129             );
130         }
131         inline::record_extern_fqn(cx, trait_ref.def_id, kind);
132         let path = external_path(cx, trait_ref.def_id, true, bounds.to_vec(), trait_ref.substs);
133 
134         debug!("ty::TraitRef\n  subst: {:?}\n", trait_ref.substs);
135 
136         path
137     }
138 }
139 
140 impl Clean<Path> for ty::TraitRef<'tcx> {
clean(&self, cx: &mut DocContext<'_>) -> Path141     fn clean(&self, cx: &mut DocContext<'_>) -> Path {
142         (*self, &[][..]).clean(cx)
143     }
144 }
145 
146 impl Clean<GenericBound> for (ty::PolyTraitRef<'_>, &[TypeBinding]) {
clean(&self, cx: &mut DocContext<'_>) -> GenericBound147     fn clean(&self, cx: &mut DocContext<'_>) -> GenericBound {
148         let (poly_trait_ref, bounds) = *self;
149         let poly_trait_ref = poly_trait_ref.lift_to_tcx(cx.tcx).unwrap();
150 
151         // collect any late bound regions
152         let late_bound_regions: Vec<_> = cx
153             .tcx
154             .collect_referenced_late_bound_regions(&poly_trait_ref)
155             .into_iter()
156             .filter_map(|br| match br {
157                 ty::BrNamed(_, name) => Some(GenericParamDef {
158                     name,
159                     kind: GenericParamDefKind::Lifetime { outlives: vec![] },
160                 }),
161                 _ => None,
162             })
163             .collect();
164 
165         GenericBound::TraitBound(
166             PolyTrait {
167                 trait_: (poly_trait_ref.skip_binder(), bounds).clean(cx),
168                 generic_params: late_bound_regions,
169             },
170             hir::TraitBoundModifier::None,
171         )
172     }
173 }
174 
175 impl<'tcx> Clean<GenericBound> for ty::PolyTraitRef<'tcx> {
clean(&self, cx: &mut DocContext<'_>) -> GenericBound176     fn clean(&self, cx: &mut DocContext<'_>) -> GenericBound {
177         (*self, &[][..]).clean(cx)
178     }
179 }
180 
181 impl Clean<Lifetime> for hir::Lifetime {
clean(&self, cx: &mut DocContext<'_>) -> Lifetime182     fn clean(&self, cx: &mut DocContext<'_>) -> Lifetime {
183         let def = cx.tcx.named_region(self.hir_id);
184         if let Some(
185             rl::Region::EarlyBound(_, node_id, _)
186             | rl::Region::LateBound(_, _, node_id, _)
187             | rl::Region::Free(_, node_id),
188         ) = def
189         {
190             if let Some(lt) = cx.substs.get(&node_id).and_then(|p| p.as_lt()).cloned() {
191                 return lt;
192             }
193         }
194         Lifetime(self.name.ident().name)
195     }
196 }
197 
198 impl Clean<Constant> for hir::ConstArg {
clean(&self, cx: &mut DocContext<'_>) -> Constant199     fn clean(&self, cx: &mut DocContext<'_>) -> Constant {
200         Constant {
201             type_: cx
202                 .tcx
203                 .type_of(cx.tcx.hir().body_owner_def_id(self.value.body).to_def_id())
204                 .clean(cx),
205             kind: ConstantKind::Anonymous { body: self.value.body },
206         }
207     }
208 }
209 
210 impl Clean<Option<Lifetime>> for ty::RegionKind {
clean(&self, _cx: &mut DocContext<'_>) -> Option<Lifetime>211     fn clean(&self, _cx: &mut DocContext<'_>) -> Option<Lifetime> {
212         match *self {
213             ty::ReStatic => Some(Lifetime::statik()),
214             ty::ReLateBound(_, ty::BoundRegion { kind: ty::BrNamed(_, name), .. }) => {
215                 Some(Lifetime(name))
216             }
217             ty::ReEarlyBound(ref data) => Some(Lifetime(data.name)),
218 
219             ty::ReLateBound(..)
220             | ty::ReFree(..)
221             | ty::ReVar(..)
222             | ty::RePlaceholder(..)
223             | ty::ReEmpty(_)
224             | ty::ReErased => {
225                 debug!("cannot clean region {:?}", self);
226                 None
227             }
228         }
229     }
230 }
231 
232 impl Clean<WherePredicate> for hir::WherePredicate<'_> {
clean(&self, cx: &mut DocContext<'_>) -> WherePredicate233     fn clean(&self, cx: &mut DocContext<'_>) -> WherePredicate {
234         match *self {
235             hir::WherePredicate::BoundPredicate(ref wbp) => {
236                 let bound_params = wbp
237                     .bound_generic_params
238                     .into_iter()
239                     .map(|param| {
240                         // Higher-ranked params must be lifetimes.
241                         // Higher-ranked lifetimes can't have bounds.
242                         assert_matches!(
243                             param,
244                             hir::GenericParam {
245                                 kind: hir::GenericParamKind::Lifetime { .. },
246                                 bounds: [],
247                                 ..
248                             }
249                         );
250                         Lifetime(param.name.ident().name)
251                     })
252                     .collect();
253                 WherePredicate::BoundPredicate {
254                     ty: wbp.bounded_ty.clean(cx),
255                     bounds: wbp.bounds.iter().map(|x| x.clean(cx)).collect(),
256                     bound_params,
257                 }
258             }
259 
260             hir::WherePredicate::RegionPredicate(ref wrp) => WherePredicate::RegionPredicate {
261                 lifetime: wrp.lifetime.clean(cx),
262                 bounds: wrp.bounds.iter().map(|x| x.clean(cx)).collect(),
263             },
264 
265             hir::WherePredicate::EqPredicate(ref wrp) => {
266                 WherePredicate::EqPredicate { lhs: wrp.lhs_ty.clean(cx), rhs: wrp.rhs_ty.clean(cx) }
267             }
268         }
269     }
270 }
271 
272 impl<'a> Clean<Option<WherePredicate>> for ty::Predicate<'a> {
clean(&self, cx: &mut DocContext<'_>) -> Option<WherePredicate>273     fn clean(&self, cx: &mut DocContext<'_>) -> Option<WherePredicate> {
274         let bound_predicate = self.kind();
275         match bound_predicate.skip_binder() {
276             ty::PredicateKind::Trait(pred) => Some(bound_predicate.rebind(pred).clean(cx)),
277             ty::PredicateKind::RegionOutlives(pred) => pred.clean(cx),
278             ty::PredicateKind::TypeOutlives(pred) => pred.clean(cx),
279             ty::PredicateKind::Projection(pred) => Some(pred.clean(cx)),
280             ty::PredicateKind::ConstEvaluatable(..) => None,
281 
282             ty::PredicateKind::Subtype(..)
283             | ty::PredicateKind::Coerce(..)
284             | ty::PredicateKind::WellFormed(..)
285             | ty::PredicateKind::ObjectSafe(..)
286             | ty::PredicateKind::ClosureKind(..)
287             | ty::PredicateKind::ConstEquate(..)
288             | ty::PredicateKind::TypeWellFormedFromEnv(..) => panic!("not user writable"),
289         }
290     }
291 }
292 
293 impl<'a> Clean<WherePredicate> for ty::PolyTraitPredicate<'a> {
clean(&self, cx: &mut DocContext<'_>) -> WherePredicate294     fn clean(&self, cx: &mut DocContext<'_>) -> WherePredicate {
295         let poly_trait_ref = self.map_bound(|pred| pred.trait_ref);
296         WherePredicate::BoundPredicate {
297             ty: poly_trait_ref.skip_binder().self_ty().clean(cx),
298             bounds: vec![poly_trait_ref.clean(cx)],
299             bound_params: Vec::new(),
300         }
301     }
302 }
303 
304 impl<'tcx> Clean<Option<WherePredicate>>
305     for ty::OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>
306 {
clean(&self, cx: &mut DocContext<'_>) -> Option<WherePredicate>307     fn clean(&self, cx: &mut DocContext<'_>) -> Option<WherePredicate> {
308         let ty::OutlivesPredicate(a, b) = self;
309 
310         if let (ty::ReEmpty(_), ty::ReEmpty(_)) = (a, b) {
311             return None;
312         }
313 
314         Some(WherePredicate::RegionPredicate {
315             lifetime: a.clean(cx).expect("failed to clean lifetime"),
316             bounds: vec![GenericBound::Outlives(b.clean(cx).expect("failed to clean bounds"))],
317         })
318     }
319 }
320 
321 impl<'tcx> Clean<Option<WherePredicate>> for ty::OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>> {
clean(&self, cx: &mut DocContext<'_>) -> Option<WherePredicate>322     fn clean(&self, cx: &mut DocContext<'_>) -> Option<WherePredicate> {
323         let ty::OutlivesPredicate(ty, lt) = self;
324 
325         if let ty::ReEmpty(_) = lt {
326             return None;
327         }
328 
329         Some(WherePredicate::BoundPredicate {
330             ty: ty.clean(cx),
331             bounds: vec![GenericBound::Outlives(lt.clean(cx).expect("failed to clean lifetimes"))],
332             bound_params: Vec::new(),
333         })
334     }
335 }
336 
337 impl<'tcx> Clean<WherePredicate> for ty::ProjectionPredicate<'tcx> {
clean(&self, cx: &mut DocContext<'_>) -> WherePredicate338     fn clean(&self, cx: &mut DocContext<'_>) -> WherePredicate {
339         let ty::ProjectionPredicate { projection_ty, ty } = self;
340         WherePredicate::EqPredicate { lhs: projection_ty.clean(cx), rhs: ty.clean(cx) }
341     }
342 }
343 
344 impl<'tcx> Clean<Type> for ty::ProjectionTy<'tcx> {
clean(&self, cx: &mut DocContext<'_>) -> Type345     fn clean(&self, cx: &mut DocContext<'_>) -> Type {
346         let lifted = self.lift_to_tcx(cx.tcx).unwrap();
347         let trait_ = lifted.trait_ref(cx.tcx).clean(cx);
348         let self_type = self.self_ty().clean(cx);
349         Type::QPath {
350             name: cx.tcx.associated_item(self.item_def_id).ident.name,
351             self_def_id: self_type.def_id(&cx.cache),
352             self_type: box self_type,
353             trait_,
354         }
355     }
356 }
357 
358 impl Clean<GenericParamDef> for ty::GenericParamDef {
clean(&self, cx: &mut DocContext<'_>) -> GenericParamDef359     fn clean(&self, cx: &mut DocContext<'_>) -> GenericParamDef {
360         let (name, kind) = match self.kind {
361             ty::GenericParamDefKind::Lifetime => {
362                 (self.name, GenericParamDefKind::Lifetime { outlives: vec![] })
363             }
364             ty::GenericParamDefKind::Type { has_default, synthetic, .. } => {
365                 let default = if has_default {
366                     let mut default = cx.tcx.type_of(self.def_id).clean(cx);
367 
368                     // We need to reassign the `self_def_id`, if there's a parent (which is the
369                     // `Self` type), so we can properly render `<Self as X>` casts, because the
370                     // information about which type `Self` is, is only present here, but not in
371                     // the cleaning process of the type itself. To resolve this and have the
372                     // `self_def_id` set, we override it here.
373                     // See https://github.com/rust-lang/rust/issues/85454
374                     if let QPath { ref mut self_def_id, .. } = default {
375                         *self_def_id = cx.tcx.parent(self.def_id);
376                     }
377 
378                     Some(default)
379                 } else {
380                     None
381                 };
382                 (
383                     self.name,
384                     GenericParamDefKind::Type {
385                         did: self.def_id,
386                         bounds: vec![], // These are filled in from the where-clauses.
387                         default: default.map(Box::new),
388                         synthetic,
389                     },
390                 )
391             }
392             ty::GenericParamDefKind::Const { has_default, .. } => (
393                 self.name,
394                 GenericParamDefKind::Const {
395                     did: self.def_id,
396                     ty: Box::new(cx.tcx.type_of(self.def_id).clean(cx)),
397                     default: match has_default {
398                         true => Some(Box::new(cx.tcx.const_param_default(self.def_id).to_string())),
399                         false => None,
400                     },
401                 },
402             ),
403         };
404 
405         GenericParamDef { name, kind }
406     }
407 }
408 
409 impl Clean<GenericParamDef> for hir::GenericParam<'_> {
clean(&self, cx: &mut DocContext<'_>) -> GenericParamDef410     fn clean(&self, cx: &mut DocContext<'_>) -> GenericParamDef {
411         let (name, kind) = match self.kind {
412             hir::GenericParamKind::Lifetime { .. } => {
413                 let outlives = self
414                     .bounds
415                     .iter()
416                     .map(|bound| match bound {
417                         hir::GenericBound::Outlives(lt) => lt.clean(cx),
418                         _ => panic!(),
419                     })
420                     .collect();
421                 (self.name.ident().name, GenericParamDefKind::Lifetime { outlives })
422             }
423             hir::GenericParamKind::Type { ref default, synthetic } => (
424                 self.name.ident().name,
425                 GenericParamDefKind::Type {
426                     did: cx.tcx.hir().local_def_id(self.hir_id).to_def_id(),
427                     bounds: self.bounds.iter().map(|x| x.clean(cx)).collect(),
428                     default: default.map(|t| t.clean(cx)).map(Box::new),
429                     synthetic,
430                 },
431             ),
432             hir::GenericParamKind::Const { ref ty, default } => (
433                 self.name.ident().name,
434                 GenericParamDefKind::Const {
435                     did: cx.tcx.hir().local_def_id(self.hir_id).to_def_id(),
436                     ty: Box::new(ty.clean(cx)),
437                     default: default.map(|ct| {
438                         let def_id = cx.tcx.hir().local_def_id(ct.hir_id);
439                         Box::new(ty::Const::from_anon_const(cx.tcx, def_id).to_string())
440                     }),
441                 },
442             ),
443         };
444 
445         GenericParamDef { name, kind }
446     }
447 }
448 
449 impl Clean<Generics> for hir::Generics<'_> {
clean(&self, cx: &mut DocContext<'_>) -> Generics450     fn clean(&self, cx: &mut DocContext<'_>) -> Generics {
451         // Synthetic type-parameters are inserted after normal ones.
452         // In order for normal parameters to be able to refer to synthetic ones,
453         // scans them first.
454         fn is_impl_trait(param: &hir::GenericParam<'_>) -> bool {
455             match param.kind {
456                 hir::GenericParamKind::Type { synthetic, .. } => synthetic,
457                 _ => false,
458             }
459         }
460         /// This can happen for `async fn`, e.g. `async fn f<'_>(&'_ self)`.
461         ///
462         /// See [`lifetime_to_generic_param`] in [`rustc_ast_lowering`] for more information.
463         ///
464         /// [`lifetime_to_generic_param`]: rustc_ast_lowering::LoweringContext::lifetime_to_generic_param
465         fn is_elided_lifetime(param: &hir::GenericParam<'_>) -> bool {
466             matches!(
467                 param.kind,
468                 hir::GenericParamKind::Lifetime { kind: hir::LifetimeParamKind::Elided }
469             )
470         }
471 
472         let impl_trait_params = self
473             .params
474             .iter()
475             .filter(|param| is_impl_trait(param))
476             .map(|param| {
477                 let param: GenericParamDef = param.clean(cx);
478                 match param.kind {
479                     GenericParamDefKind::Lifetime { .. } => unreachable!(),
480                     GenericParamDefKind::Type { did, ref bounds, .. } => {
481                         cx.impl_trait_bounds.insert(did.into(), bounds.clone());
482                     }
483                     GenericParamDefKind::Const { .. } => unreachable!(),
484                 }
485                 param
486             })
487             .collect::<Vec<_>>();
488 
489         let mut params = Vec::with_capacity(self.params.len());
490         for p in self.params.iter().filter(|p| !is_impl_trait(p) && !is_elided_lifetime(p)) {
491             let p = p.clean(cx);
492             params.push(p);
493         }
494         params.extend(impl_trait_params);
495 
496         let mut generics = Generics {
497             params,
498             where_predicates: self.where_clause.predicates.iter().map(|x| x.clean(cx)).collect(),
499         };
500 
501         // Some duplicates are generated for ?Sized bounds between type params and where
502         // predicates. The point in here is to move the bounds definitions from type params
503         // to where predicates when such cases occur.
504         for where_pred in &mut generics.where_predicates {
505             match *where_pred {
506                 WherePredicate::BoundPredicate {
507                     ty: Generic(ref name), ref mut bounds, ..
508                 } => {
509                     if bounds.is_empty() {
510                         for param in &mut generics.params {
511                             match param.kind {
512                                 GenericParamDefKind::Lifetime { .. } => {}
513                                 GenericParamDefKind::Type { bounds: ref mut ty_bounds, .. } => {
514                                     if &param.name == name {
515                                         mem::swap(bounds, ty_bounds);
516                                         break;
517                                     }
518                                 }
519                                 GenericParamDefKind::Const { .. } => {}
520                             }
521                         }
522                     }
523                 }
524                 _ => continue,
525             }
526         }
527         generics
528     }
529 }
530 
531 impl<'a, 'tcx> Clean<Generics> for (&'a ty::Generics, ty::GenericPredicates<'tcx>) {
clean(&self, cx: &mut DocContext<'_>) -> Generics532     fn clean(&self, cx: &mut DocContext<'_>) -> Generics {
533         use self::WherePredicate as WP;
534         use std::collections::BTreeMap;
535 
536         let (gens, preds) = *self;
537 
538         // Don't populate `cx.impl_trait_bounds` before `clean`ning `where` clauses,
539         // since `Clean for ty::Predicate` would consume them.
540         let mut impl_trait = BTreeMap::<ImplTraitParam, Vec<GenericBound>>::default();
541 
542         // Bounds in the type_params and lifetimes fields are repeated in the
543         // predicates field (see rustc_typeck::collect::ty_generics), so remove
544         // them.
545         let stripped_params = gens
546             .params
547             .iter()
548             .filter_map(|param| match param.kind {
549                 ty::GenericParamDefKind::Lifetime => Some(param.clean(cx)),
550                 ty::GenericParamDefKind::Type { synthetic, .. } => {
551                     if param.name == kw::SelfUpper {
552                         assert_eq!(param.index, 0);
553                         return None;
554                     }
555                     if synthetic {
556                         impl_trait.insert(param.index.into(), vec![]);
557                         return None;
558                     }
559                     Some(param.clean(cx))
560                 }
561                 ty::GenericParamDefKind::Const { .. } => Some(param.clean(cx)),
562             })
563             .collect::<Vec<GenericParamDef>>();
564 
565         // param index -> [(DefId of trait, associated type name, type)]
566         let mut impl_trait_proj = FxHashMap::<u32, Vec<(DefId, Symbol, Ty<'tcx>)>>::default();
567 
568         let where_predicates = preds
569             .predicates
570             .iter()
571             .flat_map(|(p, _)| {
572                 let mut projection = None;
573                 let param_idx = (|| {
574                     let bound_p = p.kind();
575                     match bound_p.skip_binder() {
576                         ty::PredicateKind::Trait(pred) => {
577                             if let ty::Param(param) = pred.self_ty().kind() {
578                                 return Some(param.index);
579                             }
580                         }
581                         ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(ty, _reg)) => {
582                             if let ty::Param(param) = ty.kind() {
583                                 return Some(param.index);
584                             }
585                         }
586                         ty::PredicateKind::Projection(p) => {
587                             if let ty::Param(param) = p.projection_ty.self_ty().kind() {
588                                 projection = Some(bound_p.rebind(p));
589                                 return Some(param.index);
590                             }
591                         }
592                         _ => (),
593                     }
594 
595                     None
596                 })();
597 
598                 if let Some(param_idx) = param_idx {
599                     if let Some(b) = impl_trait.get_mut(&param_idx.into()) {
600                         let p = p.clean(cx)?;
601 
602                         b.extend(
603                             p.get_bounds()
604                                 .into_iter()
605                                 .flatten()
606                                 .cloned()
607                                 .filter(|b| !b.is_sized_bound(cx)),
608                         );
609 
610                         let proj = projection
611                             .map(|p| (p.skip_binder().projection_ty.clean(cx), p.skip_binder().ty));
612                         if let Some(((_, trait_did, name), rhs)) =
613                             proj.as_ref().and_then(|(lhs, rhs)| Some((lhs.projection()?, rhs)))
614                         {
615                             impl_trait_proj
616                                 .entry(param_idx)
617                                 .or_default()
618                                 .push((trait_did, name, rhs));
619                         }
620 
621                         return None;
622                     }
623                 }
624 
625                 Some(p)
626             })
627             .collect::<Vec<_>>();
628 
629         for (param, mut bounds) in impl_trait {
630             // Move trait bounds to the front.
631             bounds.sort_by_key(|b| !matches!(b, GenericBound::TraitBound(..)));
632 
633             if let crate::core::ImplTraitParam::ParamIndex(idx) = param {
634                 if let Some(proj) = impl_trait_proj.remove(&idx) {
635                     for (trait_did, name, rhs) in proj {
636                         let rhs = rhs.clean(cx);
637                         simplify::merge_bounds(cx, &mut bounds, trait_did, name, &rhs);
638                     }
639                 }
640             } else {
641                 unreachable!();
642             }
643 
644             cx.impl_trait_bounds.insert(param, bounds);
645         }
646 
647         // Now that `cx.impl_trait_bounds` is populated, we can process
648         // remaining predicates which could contain `impl Trait`.
649         let mut where_predicates =
650             where_predicates.into_iter().flat_map(|p| p.clean(cx)).collect::<Vec<_>>();
651 
652         // Type parameters have a Sized bound by default unless removed with
653         // ?Sized. Scan through the predicates and mark any type parameter with
654         // a Sized bound, removing the bounds as we find them.
655         //
656         // Note that associated types also have a sized bound by default, but we
657         // don't actually know the set of associated types right here so that's
658         // handled in cleaning associated types
659         let mut sized_params = FxHashSet::default();
660         where_predicates.retain(|pred| match *pred {
661             WP::BoundPredicate { ty: Generic(ref g), ref bounds, .. } => {
662                 if bounds.iter().any(|b| b.is_sized_bound(cx)) {
663                     sized_params.insert(*g);
664                     false
665                 } else {
666                     true
667                 }
668             }
669             _ => true,
670         });
671 
672         // Run through the type parameters again and insert a ?Sized
673         // unbound for any we didn't find to be Sized.
674         for tp in &stripped_params {
675             if matches!(tp.kind, types::GenericParamDefKind::Type { .. })
676                 && !sized_params.contains(&tp.name)
677             {
678                 where_predicates.push(WP::BoundPredicate {
679                     ty: Type::Generic(tp.name),
680                     bounds: vec![GenericBound::maybe_sized(cx)],
681                     bound_params: Vec::new(),
682                 })
683             }
684         }
685 
686         // It would be nice to collect all of the bounds on a type and recombine
687         // them if possible, to avoid e.g., `where T: Foo, T: Bar, T: Sized, T: 'a`
688         // and instead see `where T: Foo + Bar + Sized + 'a`
689 
690         Generics {
691             params: stripped_params,
692             where_predicates: simplify::where_clauses(cx, where_predicates),
693         }
694     }
695 }
696 
clean_fn_or_proc_macro( item: &hir::Item<'_>, sig: &'a hir::FnSig<'a>, generics: &'a hir::Generics<'a>, body_id: hir::BodyId, name: &mut Symbol, cx: &mut DocContext<'_>, ) -> ItemKind697 fn clean_fn_or_proc_macro(
698     item: &hir::Item<'_>,
699     sig: &'a hir::FnSig<'a>,
700     generics: &'a hir::Generics<'a>,
701     body_id: hir::BodyId,
702     name: &mut Symbol,
703     cx: &mut DocContext<'_>,
704 ) -> ItemKind {
705     let attrs = cx.tcx.hir().attrs(item.hir_id());
706     let macro_kind = attrs.iter().find_map(|a| {
707         if a.has_name(sym::proc_macro) {
708             Some(MacroKind::Bang)
709         } else if a.has_name(sym::proc_macro_derive) {
710             Some(MacroKind::Derive)
711         } else if a.has_name(sym::proc_macro_attribute) {
712             Some(MacroKind::Attr)
713         } else {
714             None
715         }
716     });
717     match macro_kind {
718         Some(kind) => {
719             if kind == MacroKind::Derive {
720                 *name = attrs
721                     .lists(sym::proc_macro_derive)
722                     .find_map(|mi| mi.ident())
723                     .expect("proc-macro derives require a name")
724                     .name;
725             }
726 
727             let mut helpers = Vec::new();
728             for mi in attrs.lists(sym::proc_macro_derive) {
729                 if !mi.has_name(sym::attributes) {
730                     continue;
731                 }
732 
733                 if let Some(list) = mi.meta_item_list() {
734                     for inner_mi in list {
735                         if let Some(ident) = inner_mi.ident() {
736                             helpers.push(ident.name);
737                         }
738                     }
739                 }
740             }
741             ProcMacroItem(ProcMacro { kind, helpers })
742         }
743         None => {
744             let mut func = (sig, generics, body_id).clean(cx);
745             let def_id = item.def_id.to_def_id();
746             func.header.constness =
747                 if cx.tcx.is_const_fn(def_id) && is_unstable_const_fn(cx.tcx, def_id).is_none() {
748                     hir::Constness::Const
749                 } else {
750                     hir::Constness::NotConst
751                 };
752             FunctionItem(func)
753         }
754     }
755 }
756 
757 impl<'a> Clean<Function> for (&'a hir::FnSig<'a>, &'a hir::Generics<'a>, hir::BodyId) {
clean(&self, cx: &mut DocContext<'_>) -> Function758     fn clean(&self, cx: &mut DocContext<'_>) -> Function {
759         let (generics, decl) = enter_impl_trait(cx, |cx| {
760             // NOTE: generics must be cleaned before args
761             let generics = self.1.clean(cx);
762             let args = (self.0.decl.inputs, self.2).clean(cx);
763             let decl = clean_fn_decl_with_args(cx, self.0.decl, args);
764             (generics, decl)
765         });
766         Function { decl, generics, header: self.0.header }
767     }
768 }
769 
770 impl<'a> Clean<Arguments> for (&'a [hir::Ty<'a>], &'a [Ident]) {
clean(&self, cx: &mut DocContext<'_>) -> Arguments771     fn clean(&self, cx: &mut DocContext<'_>) -> Arguments {
772         Arguments {
773             values: self
774                 .0
775                 .iter()
776                 .enumerate()
777                 .map(|(i, ty)| {
778                     let mut name = self.1.get(i).map_or(kw::Empty, |ident| ident.name);
779                     if name.is_empty() {
780                         name = kw::Underscore;
781                     }
782                     Argument { name, type_: ty.clean(cx) }
783                 })
784                 .collect(),
785         }
786     }
787 }
788 
789 impl<'a> Clean<Arguments> for (&'a [hir::Ty<'a>], hir::BodyId) {
clean(&self, cx: &mut DocContext<'_>) -> Arguments790     fn clean(&self, cx: &mut DocContext<'_>) -> Arguments {
791         let body = cx.tcx.hir().body(self.1);
792 
793         Arguments {
794             values: self
795                 .0
796                 .iter()
797                 .enumerate()
798                 .map(|(i, ty)| Argument {
799                     name: name_from_pat(body.params[i].pat),
800                     type_: ty.clean(cx),
801                 })
802                 .collect(),
803         }
804     }
805 }
806 
clean_fn_decl_with_args( cx: &mut DocContext<'_>, decl: &hir::FnDecl<'_>, args: Arguments, ) -> FnDecl807 fn clean_fn_decl_with_args(
808     cx: &mut DocContext<'_>,
809     decl: &hir::FnDecl<'_>,
810     args: Arguments,
811 ) -> FnDecl {
812     FnDecl { inputs: args, output: decl.output.clean(cx), c_variadic: decl.c_variadic }
813 }
814 
815 impl<'tcx> Clean<FnDecl> for (DefId, ty::PolyFnSig<'tcx>) {
clean(&self, cx: &mut DocContext<'_>) -> FnDecl816     fn clean(&self, cx: &mut DocContext<'_>) -> FnDecl {
817         let (did, sig) = *self;
818         let mut names = if did.is_local() { &[] } else { cx.tcx.fn_arg_names(did) }.iter();
819 
820         FnDecl {
821             output: Return(sig.skip_binder().output().clean(cx)),
822             c_variadic: sig.skip_binder().c_variadic,
823             inputs: Arguments {
824                 values: sig
825                     .skip_binder()
826                     .inputs()
827                     .iter()
828                     .map(|t| Argument {
829                         type_: t.clean(cx),
830                         name: names.next().map_or(kw::Empty, |i| i.name),
831                     })
832                     .collect(),
833             },
834         }
835     }
836 }
837 
838 impl Clean<FnRetTy> for hir::FnRetTy<'_> {
clean(&self, cx: &mut DocContext<'_>) -> FnRetTy839     fn clean(&self, cx: &mut DocContext<'_>) -> FnRetTy {
840         match *self {
841             Self::Return(ref typ) => Return(typ.clean(cx)),
842             Self::DefaultReturn(..) => DefaultReturn,
843         }
844     }
845 }
846 
847 impl Clean<bool> for hir::IsAuto {
clean(&self, _: &mut DocContext<'_>) -> bool848     fn clean(&self, _: &mut DocContext<'_>) -> bool {
849         match *self {
850             hir::IsAuto::Yes => true,
851             hir::IsAuto::No => false,
852         }
853     }
854 }
855 
856 impl Clean<Path> for hir::TraitRef<'_> {
clean(&self, cx: &mut DocContext<'_>) -> Path857     fn clean(&self, cx: &mut DocContext<'_>) -> Path {
858         let path = self.path.clean(cx);
859         register_res(cx, path.res);
860         path
861     }
862 }
863 
864 impl Clean<PolyTrait> for hir::PolyTraitRef<'_> {
clean(&self, cx: &mut DocContext<'_>) -> PolyTrait865     fn clean(&self, cx: &mut DocContext<'_>) -> PolyTrait {
866         PolyTrait {
867             trait_: self.trait_ref.clean(cx),
868             generic_params: self.bound_generic_params.iter().map(|x| x.clean(cx)).collect(),
869         }
870     }
871 }
872 
873 impl Clean<Item> for hir::TraitItem<'_> {
clean(&self, cx: &mut DocContext<'_>) -> Item874     fn clean(&self, cx: &mut DocContext<'_>) -> Item {
875         let local_did = self.def_id.to_def_id();
876         cx.with_param_env(local_did, |cx| {
877             let inner = match self.kind {
878                 hir::TraitItemKind::Const(ref ty, default) => {
879                     AssocConstItem(ty.clean(cx), default.map(|e| print_const_expr(cx.tcx, e)))
880                 }
881                 hir::TraitItemKind::Fn(ref sig, hir::TraitFn::Provided(body)) => {
882                     let mut m = (sig, &self.generics, body).clean(cx);
883                     if m.header.constness == hir::Constness::Const
884                         && is_unstable_const_fn(cx.tcx, local_did).is_some()
885                     {
886                         m.header.constness = hir::Constness::NotConst;
887                     }
888                     MethodItem(m, None)
889                 }
890                 hir::TraitItemKind::Fn(ref sig, hir::TraitFn::Required(names)) => {
891                     let (generics, decl) = enter_impl_trait(cx, |cx| {
892                         // NOTE: generics must be cleaned before args
893                         let generics = self.generics.clean(cx);
894                         let args = (sig.decl.inputs, names).clean(cx);
895                         let decl = clean_fn_decl_with_args(cx, sig.decl, args);
896                         (generics, decl)
897                     });
898                     let mut t = Function { header: sig.header, decl, generics };
899                     if t.header.constness == hir::Constness::Const
900                         && is_unstable_const_fn(cx.tcx, local_did).is_some()
901                     {
902                         t.header.constness = hir::Constness::NotConst;
903                     }
904                     TyMethodItem(t)
905                 }
906                 hir::TraitItemKind::Type(bounds, ref default) => {
907                     let bounds = bounds.iter().map(|x| x.clean(cx)).collect();
908                     let default = default.map(|t| t.clean(cx));
909                     AssocTypeItem(bounds, default)
910                 }
911             };
912             let what_rustc_thinks =
913                 Item::from_def_id_and_parts(local_did, Some(self.ident.name), inner, cx);
914             // Trait items always inherit the trait's visibility -- we don't want to show `pub`.
915             Item { visibility: Inherited, ..what_rustc_thinks }
916         })
917     }
918 }
919 
920 impl Clean<Item> for hir::ImplItem<'_> {
clean(&self, cx: &mut DocContext<'_>) -> Item921     fn clean(&self, cx: &mut DocContext<'_>) -> Item {
922         let local_did = self.def_id.to_def_id();
923         cx.with_param_env(local_did, |cx| {
924             let inner = match self.kind {
925                 hir::ImplItemKind::Const(ref ty, expr) => {
926                     AssocConstItem(ty.clean(cx), Some(print_const_expr(cx.tcx, expr)))
927                 }
928                 hir::ImplItemKind::Fn(ref sig, body) => {
929                     let mut m = (sig, &self.generics, body).clean(cx);
930                     if m.header.constness == hir::Constness::Const
931                         && is_unstable_const_fn(cx.tcx, local_did).is_some()
932                     {
933                         m.header.constness = hir::Constness::NotConst;
934                     }
935                     MethodItem(m, Some(self.defaultness))
936                 }
937                 hir::ImplItemKind::TyAlias(ref hir_ty) => {
938                     let type_ = hir_ty.clean(cx);
939                     let item_type = hir_ty_to_ty(cx.tcx, hir_ty).clean(cx);
940                     TypedefItem(
941                         Typedef {
942                             type_,
943                             generics: Generics::default(),
944                             item_type: Some(item_type),
945                         },
946                         true,
947                     )
948                 }
949             };
950 
951             let what_rustc_thinks =
952                 Item::from_def_id_and_parts(local_did, Some(self.ident.name), inner, cx);
953             let parent_item = cx.tcx.hir().expect_item(cx.tcx.hir().get_parent_item(self.hir_id()));
954             if let hir::ItemKind::Impl(impl_) = &parent_item.kind {
955                 if impl_.of_trait.is_some() {
956                     // Trait impl items always inherit the impl's visibility --
957                     // we don't want to show `pub`.
958                     Item { visibility: Inherited, ..what_rustc_thinks }
959                 } else {
960                     what_rustc_thinks
961                 }
962             } else {
963                 panic!("found impl item with non-impl parent {:?}", parent_item);
964             }
965         })
966     }
967 }
968 
969 impl Clean<Item> for ty::AssocItem {
clean(&self, cx: &mut DocContext<'_>) -> Item970     fn clean(&self, cx: &mut DocContext<'_>) -> Item {
971         let tcx = cx.tcx;
972         let kind = match self.kind {
973             ty::AssocKind::Const => {
974                 let ty = tcx.type_of(self.def_id);
975                 let default = if self.defaultness.has_value() {
976                     Some(inline::print_inlined_const(tcx, self.def_id))
977                 } else {
978                     None
979                 };
980                 AssocConstItem(ty.clean(cx), default)
981             }
982             ty::AssocKind::Fn => {
983                 let generics =
984                     (tcx.generics_of(self.def_id), tcx.explicit_predicates_of(self.def_id))
985                         .clean(cx);
986                 let sig = tcx.fn_sig(self.def_id);
987                 let mut decl = (self.def_id, sig).clean(cx);
988 
989                 if self.fn_has_self_parameter {
990                     let self_ty = match self.container {
991                         ty::ImplContainer(def_id) => tcx.type_of(def_id),
992                         ty::TraitContainer(_) => tcx.types.self_param,
993                     };
994                     let self_arg_ty = sig.input(0).skip_binder();
995                     if self_arg_ty == self_ty {
996                         decl.inputs.values[0].type_ = Generic(kw::SelfUpper);
997                     } else if let ty::Ref(_, ty, _) = *self_arg_ty.kind() {
998                         if ty == self_ty {
999                             match decl.inputs.values[0].type_ {
1000                                 BorrowedRef { ref mut type_, .. } => {
1001                                     **type_ = Generic(kw::SelfUpper)
1002                                 }
1003                                 _ => unreachable!(),
1004                             }
1005                         }
1006                     }
1007                 }
1008 
1009                 let provided = match self.container {
1010                     ty::ImplContainer(_) => true,
1011                     ty::TraitContainer(_) => self.defaultness.has_value(),
1012                 };
1013                 if provided {
1014                     let constness = if tcx.is_const_fn_raw(self.def_id) {
1015                         hir::Constness::Const
1016                     } else {
1017                         hir::Constness::NotConst
1018                     };
1019                     let asyncness = tcx.asyncness(self.def_id);
1020                     let defaultness = match self.container {
1021                         ty::ImplContainer(_) => Some(self.defaultness),
1022                         ty::TraitContainer(_) => None,
1023                     };
1024                     MethodItem(
1025                         Function {
1026                             generics,
1027                             decl,
1028                             header: hir::FnHeader {
1029                                 unsafety: sig.unsafety(),
1030                                 abi: sig.abi(),
1031                                 constness,
1032                                 asyncness,
1033                             },
1034                         },
1035                         defaultness,
1036                     )
1037                 } else {
1038                     TyMethodItem(Function {
1039                         generics,
1040                         decl,
1041                         header: hir::FnHeader {
1042                             unsafety: sig.unsafety(),
1043                             abi: sig.abi(),
1044                             constness: hir::Constness::NotConst,
1045                             asyncness: hir::IsAsync::NotAsync,
1046                         },
1047                     })
1048                 }
1049             }
1050             ty::AssocKind::Type => {
1051                 let my_name = self.ident.name;
1052 
1053                 if let ty::TraitContainer(_) = self.container {
1054                     let bounds = tcx.explicit_item_bounds(self.def_id);
1055                     let predicates = ty::GenericPredicates { parent: None, predicates: bounds };
1056                     let generics = (tcx.generics_of(self.def_id), predicates).clean(cx);
1057                     let mut bounds = generics
1058                         .where_predicates
1059                         .iter()
1060                         .filter_map(|pred| {
1061                             let (name, self_type, trait_, bounds) = match *pred {
1062                                 WherePredicate::BoundPredicate {
1063                                     ty: QPath { ref name, ref self_type, ref trait_, .. },
1064                                     ref bounds,
1065                                     ..
1066                                 } => (name, self_type, trait_, bounds),
1067                                 _ => return None,
1068                             };
1069                             if *name != my_name {
1070                                 return None;
1071                             }
1072                             if trait_.def_id() != self.container.id() {
1073                                 return None;
1074                             }
1075                             match **self_type {
1076                                 Generic(ref s) if *s == kw::SelfUpper => {}
1077                                 _ => return None,
1078                             }
1079                             Some(bounds)
1080                         })
1081                         .flat_map(|i| i.iter().cloned())
1082                         .collect::<Vec<_>>();
1083                     // Our Sized/?Sized bound didn't get handled when creating the generics
1084                     // because we didn't actually get our whole set of bounds until just now
1085                     // (some of them may have come from the trait). If we do have a sized
1086                     // bound, we remove it, and if we don't then we add the `?Sized` bound
1087                     // at the end.
1088                     match bounds.iter().position(|b| b.is_sized_bound(cx)) {
1089                         Some(i) => {
1090                             bounds.remove(i);
1091                         }
1092                         None => bounds.push(GenericBound::maybe_sized(cx)),
1093                     }
1094 
1095                     let ty = if self.defaultness.has_value() {
1096                         Some(tcx.type_of(self.def_id))
1097                     } else {
1098                         None
1099                     };
1100 
1101                     AssocTypeItem(bounds, ty.map(|t| t.clean(cx)))
1102                 } else {
1103                     // FIXME: when could this happen? Associated items in inherent impls?
1104                     let type_ = tcx.type_of(self.def_id).clean(cx);
1105                     TypedefItem(
1106                         Typedef {
1107                             type_,
1108                             generics: Generics { params: Vec::new(), where_predicates: Vec::new() },
1109                             item_type: None,
1110                         },
1111                         true,
1112                     )
1113                 }
1114             }
1115         };
1116 
1117         Item::from_def_id_and_parts(self.def_id, Some(self.ident.name), kind, cx)
1118     }
1119 }
1120 
clean_qpath(hir_ty: &hir::Ty<'_>, cx: &mut DocContext<'_>) -> Type1121 fn clean_qpath(hir_ty: &hir::Ty<'_>, cx: &mut DocContext<'_>) -> Type {
1122     let hir::Ty { hir_id: _, span, ref kind } = *hir_ty;
1123     let qpath = match kind {
1124         hir::TyKind::Path(qpath) => qpath,
1125         _ => unreachable!(),
1126     };
1127 
1128     match qpath {
1129         hir::QPath::Resolved(None, ref path) => {
1130             if let Res::Def(DefKind::TyParam, did) = path.res {
1131                 if let Some(new_ty) = cx.substs.get(&did).and_then(|p| p.as_ty()).cloned() {
1132                     return new_ty;
1133                 }
1134                 if let Some(bounds) = cx.impl_trait_bounds.remove(&did.into()) {
1135                     return ImplTrait(bounds);
1136                 }
1137             }
1138 
1139             if let Some(expanded) = maybe_expand_private_type_alias(cx, path) {
1140                 expanded
1141             } else {
1142                 let path = path.clean(cx);
1143                 resolve_type(cx, path)
1144             }
1145         }
1146         hir::QPath::Resolved(Some(ref qself), p) => {
1147             // Try to normalize `<X as Y>::T` to a type
1148             let ty = hir_ty_to_ty(cx.tcx, hir_ty);
1149             if let Some(normalized_value) = normalize(cx, ty) {
1150                 return normalized_value.clean(cx);
1151             }
1152 
1153             let trait_segments = &p.segments[..p.segments.len() - 1];
1154             let trait_def = cx.tcx.associated_item(p.res.def_id()).container.id();
1155             let trait_ = self::Path {
1156                 res: Res::Def(DefKind::Trait, trait_def),
1157                 segments: trait_segments.iter().map(|x| x.clean(cx)).collect(),
1158             };
1159             register_res(cx, trait_.res);
1160             Type::QPath {
1161                 name: p.segments.last().expect("segments were empty").ident.name,
1162                 self_def_id: Some(DefId::local(qself.hir_id.owner.local_def_index)),
1163                 self_type: box qself.clean(cx),
1164                 trait_,
1165             }
1166         }
1167         hir::QPath::TypeRelative(ref qself, segment) => {
1168             let ty = hir_ty_to_ty(cx.tcx, hir_ty);
1169             let res = match ty.kind() {
1170                 ty::Projection(proj) => Res::Def(DefKind::Trait, proj.trait_ref(cx.tcx).def_id),
1171                 // Rustdoc handles `ty::Error`s by turning them into `Type::Infer`s.
1172                 ty::Error(_) => return Type::Infer,
1173                 _ => bug!("clean: expected associated type, found `{:?}`", ty),
1174             };
1175             let trait_ = hir::Path { span, res, segments: &[] }.clean(cx);
1176             register_res(cx, trait_.res);
1177             Type::QPath {
1178                 name: segment.ident.name,
1179                 self_def_id: res.opt_def_id(),
1180                 self_type: box qself.clean(cx),
1181                 trait_,
1182             }
1183         }
1184         hir::QPath::LangItem(..) => bug!("clean: requiring documentation of lang item"),
1185     }
1186 }
1187 
maybe_expand_private_type_alias(cx: &mut DocContext<'_>, path: &hir::Path<'_>) -> Option<Type>1188 fn maybe_expand_private_type_alias(cx: &mut DocContext<'_>, path: &hir::Path<'_>) -> Option<Type> {
1189     let Res::Def(DefKind::TyAlias, def_id) = path.res else { return None };
1190     // Substitute private type aliases
1191     let Some(def_id) = def_id.as_local() else { return None };
1192     let hir_id = cx.tcx.hir().local_def_id_to_hir_id(def_id);
1193     let alias = if !cx.cache.access_levels.is_exported(def_id.to_def_id()) {
1194         &cx.tcx.hir().expect_item(hir_id).kind
1195     } else {
1196         return None;
1197     };
1198     let hir::ItemKind::TyAlias(ty, generics) = alias else { return None };
1199 
1200     let provided_params = &path.segments.last().expect("segments were empty");
1201     let mut substs = FxHashMap::default();
1202     let generic_args = provided_params.args();
1203 
1204     let mut indices: hir::GenericParamCount = Default::default();
1205     for param in generics.params.iter() {
1206         match param.kind {
1207             hir::GenericParamKind::Lifetime { .. } => {
1208                 let mut j = 0;
1209                 let lifetime = generic_args.args.iter().find_map(|arg| match arg {
1210                     hir::GenericArg::Lifetime(lt) => {
1211                         if indices.lifetimes == j {
1212                             return Some(lt);
1213                         }
1214                         j += 1;
1215                         None
1216                     }
1217                     _ => None,
1218                 });
1219                 if let Some(lt) = lifetime.cloned() {
1220                     let lt_def_id = cx.tcx.hir().local_def_id(param.hir_id);
1221                     let cleaned = if !lt.is_elided() {
1222                         lt.clean(cx)
1223                     } else {
1224                         self::types::Lifetime::elided()
1225                     };
1226                     substs.insert(lt_def_id.to_def_id(), SubstParam::Lifetime(cleaned));
1227                 }
1228                 indices.lifetimes += 1;
1229             }
1230             hir::GenericParamKind::Type { ref default, .. } => {
1231                 let ty_param_def_id = cx.tcx.hir().local_def_id(param.hir_id);
1232                 let mut j = 0;
1233                 let type_ = generic_args.args.iter().find_map(|arg| match arg {
1234                     hir::GenericArg::Type(ty) => {
1235                         if indices.types == j {
1236                             return Some(ty);
1237                         }
1238                         j += 1;
1239                         None
1240                     }
1241                     _ => None,
1242                 });
1243                 if let Some(ty) = type_ {
1244                     substs.insert(ty_param_def_id.to_def_id(), SubstParam::Type(ty.clean(cx)));
1245                 } else if let Some(default) = *default {
1246                     substs.insert(ty_param_def_id.to_def_id(), SubstParam::Type(default.clean(cx)));
1247                 }
1248                 indices.types += 1;
1249             }
1250             hir::GenericParamKind::Const { .. } => {
1251                 let const_param_def_id = cx.tcx.hir().local_def_id(param.hir_id);
1252                 let mut j = 0;
1253                 let const_ = generic_args.args.iter().find_map(|arg| match arg {
1254                     hir::GenericArg::Const(ct) => {
1255                         if indices.consts == j {
1256                             return Some(ct);
1257                         }
1258                         j += 1;
1259                         None
1260                     }
1261                     _ => None,
1262                 });
1263                 if let Some(ct) = const_ {
1264                     substs
1265                         .insert(const_param_def_id.to_def_id(), SubstParam::Constant(ct.clean(cx)));
1266                 }
1267                 // FIXME(const_generics_defaults)
1268                 indices.consts += 1;
1269             }
1270         }
1271     }
1272 
1273     Some(cx.enter_alias(substs, |cx| ty.clean(cx)))
1274 }
1275 
1276 impl Clean<Type> for hir::Ty<'_> {
clean(&self, cx: &mut DocContext<'_>) -> Type1277     fn clean(&self, cx: &mut DocContext<'_>) -> Type {
1278         use rustc_hir::*;
1279 
1280         match self.kind {
1281             TyKind::Never => Primitive(PrimitiveType::Never),
1282             TyKind::Ptr(ref m) => RawPointer(m.mutbl, box m.ty.clean(cx)),
1283             TyKind::Rptr(ref l, ref m) => {
1284                 // There are two times a `Fresh` lifetime can be created:
1285                 // 1. For `&'_ x`, written by the user. This corresponds to `lower_lifetime` in `rustc_ast_lowering`.
1286                 // 2. For `&x` as a parameter to an `async fn`. This corresponds to `elided_ref_lifetime in `rustc_ast_lowering`.
1287                 //    See #59286 for more information.
1288                 // Ideally we would only hide the `'_` for case 2., but I don't know a way to distinguish it.
1289                 // Turning `fn f(&'_ self)` into `fn f(&self)` isn't the worst thing in the world, though;
1290                 // there's no case where it could cause the function to fail to compile.
1291                 let elided =
1292                     l.is_elided() || matches!(l.name, LifetimeName::Param(ParamName::Fresh(_)));
1293                 let lifetime = if elided { None } else { Some(l.clean(cx)) };
1294                 BorrowedRef { lifetime, mutability: m.mutbl, type_: box m.ty.clean(cx) }
1295             }
1296             TyKind::Slice(ref ty) => Slice(box ty.clean(cx)),
1297             TyKind::Array(ref ty, ref length) => {
1298                 let def_id = cx.tcx.hir().local_def_id(length.hir_id);
1299                 // NOTE(min_const_generics): We can't use `const_eval_poly` for constants
1300                 // as we currently do not supply the parent generics to anonymous constants
1301                 // but do allow `ConstKind::Param`.
1302                 //
1303                 // `const_eval_poly` tries to to first substitute generic parameters which
1304                 // results in an ICE while manually constructing the constant and using `eval`
1305                 // does nothing for `ConstKind::Param`.
1306                 let ct = ty::Const::from_anon_const(cx.tcx, def_id);
1307                 let param_env = cx.tcx.param_env(def_id);
1308                 let length = print_const(cx, ct.eval(cx.tcx, param_env));
1309                 Array(box ty.clean(cx), length)
1310             }
1311             TyKind::Tup(tys) => Tuple(tys.iter().map(|x| x.clean(cx)).collect()),
1312             TyKind::OpaqueDef(item_id, _) => {
1313                 let item = cx.tcx.hir().item(item_id);
1314                 if let hir::ItemKind::OpaqueTy(ref ty) = item.kind {
1315                     ImplTrait(ty.bounds.iter().map(|x| x.clean(cx)).collect())
1316                 } else {
1317                     unreachable!()
1318                 }
1319             }
1320             TyKind::Path(_) => clean_qpath(self, cx),
1321             TyKind::TraitObject(bounds, ref lifetime, _) => {
1322                 let bounds = bounds.iter().map(|bound| bound.clean(cx)).collect();
1323                 let lifetime = if !lifetime.is_elided() { Some(lifetime.clean(cx)) } else { None };
1324                 DynTrait(bounds, lifetime)
1325             }
1326             TyKind::BareFn(ref barefn) => BareFunction(box barefn.clean(cx)),
1327             // Rustdoc handles `TyKind::Err`s by turning them into `Type::Infer`s.
1328             TyKind::Infer | TyKind::Err => Infer,
1329             TyKind::Typeof(..) => panic!("unimplemented type {:?}", self.kind),
1330         }
1331     }
1332 }
1333 
1334 /// Returns `None` if the type could not be normalized
normalize(cx: &mut DocContext<'tcx>, ty: Ty<'_>) -> Option<Ty<'tcx>>1335 fn normalize(cx: &mut DocContext<'tcx>, ty: Ty<'_>) -> Option<Ty<'tcx>> {
1336     // HACK: low-churn fix for #79459 while we wait for a trait normalization fix
1337     if !cx.tcx.sess.opts.debugging_opts.normalize_docs {
1338         return None;
1339     }
1340 
1341     use crate::rustc_trait_selection::infer::TyCtxtInferExt;
1342     use crate::rustc_trait_selection::traits::query::normalize::AtExt;
1343     use rustc_middle::traits::ObligationCause;
1344 
1345     // Try to normalize `<X as Y>::T` to a type
1346     let lifted = ty.lift_to_tcx(cx.tcx).unwrap();
1347     let normalized = cx.tcx.infer_ctxt().enter(|infcx| {
1348         infcx
1349             .at(&ObligationCause::dummy(), cx.param_env)
1350             .normalize(lifted)
1351             .map(|resolved| infcx.resolve_vars_if_possible(resolved.value))
1352     });
1353     match normalized {
1354         Ok(normalized_value) => {
1355             debug!("normalized {:?} to {:?}", ty, normalized_value);
1356             Some(normalized_value)
1357         }
1358         Err(err) => {
1359             debug!("failed to normalize {:?}: {:?}", ty, err);
1360             None
1361         }
1362     }
1363 }
1364 
1365 impl<'tcx> Clean<Type> for Ty<'tcx> {
clean(&self, cx: &mut DocContext<'_>) -> Type1366     fn clean(&self, cx: &mut DocContext<'_>) -> Type {
1367         trace!("cleaning type: {:?}", self);
1368         let ty = normalize(cx, self).unwrap_or(self);
1369         match *ty.kind() {
1370             ty::Never => Primitive(PrimitiveType::Never),
1371             ty::Bool => Primitive(PrimitiveType::Bool),
1372             ty::Char => Primitive(PrimitiveType::Char),
1373             ty::Int(int_ty) => Primitive(int_ty.into()),
1374             ty::Uint(uint_ty) => Primitive(uint_ty.into()),
1375             ty::Float(float_ty) => Primitive(float_ty.into()),
1376             ty::Str => Primitive(PrimitiveType::Str),
1377             ty::Slice(ty) => Slice(box ty.clean(cx)),
1378             ty::Array(ty, n) => {
1379                 let mut n = cx.tcx.lift(n).expect("array lift failed");
1380                 n = n.eval(cx.tcx, ty::ParamEnv::reveal_all());
1381                 let n = print_const(cx, n);
1382                 Array(box ty.clean(cx), n)
1383             }
1384             ty::RawPtr(mt) => RawPointer(mt.mutbl, box mt.ty.clean(cx)),
1385             ty::Ref(r, ty, mutbl) => {
1386                 BorrowedRef { lifetime: r.clean(cx), mutability: mutbl, type_: box ty.clean(cx) }
1387             }
1388             ty::FnDef(..) | ty::FnPtr(_) => {
1389                 let ty = cx.tcx.lift(*self).expect("FnPtr lift failed");
1390                 let sig = ty.fn_sig(cx.tcx);
1391                 let def_id = DefId::local(CRATE_DEF_INDEX);
1392                 BareFunction(box BareFunctionDecl {
1393                     unsafety: sig.unsafety(),
1394                     generic_params: Vec::new(),
1395                     decl: (def_id, sig).clean(cx),
1396                     abi: sig.abi(),
1397                 })
1398             }
1399             ty::Adt(def, substs) => {
1400                 let did = def.did;
1401                 let kind = match def.adt_kind() {
1402                     AdtKind::Struct => ItemType::Struct,
1403                     AdtKind::Union => ItemType::Union,
1404                     AdtKind::Enum => ItemType::Enum,
1405                 };
1406                 inline::record_extern_fqn(cx, did, kind);
1407                 let path = external_path(cx, did, false, vec![], substs);
1408                 Type::Path { path }
1409             }
1410             ty::Foreign(did) => {
1411                 inline::record_extern_fqn(cx, did, ItemType::ForeignType);
1412                 let path = external_path(cx, did, false, vec![], InternalSubsts::empty());
1413                 Type::Path { path }
1414             }
1415             ty::Dynamic(obj, ref reg) => {
1416                 // HACK: pick the first `did` as the `did` of the trait object. Someone
1417                 // might want to implement "native" support for marker-trait-only
1418                 // trait objects.
1419                 let mut dids = obj.principal_def_id().into_iter().chain(obj.auto_traits());
1420                 let did = dids
1421                     .next()
1422                     .unwrap_or_else(|| panic!("found trait object `{:?}` with no traits?", self));
1423                 let substs = match obj.principal() {
1424                     Some(principal) => principal.skip_binder().substs,
1425                     // marker traits have no substs.
1426                     _ => cx.tcx.intern_substs(&[]),
1427                 };
1428 
1429                 inline::record_extern_fqn(cx, did, ItemType::Trait);
1430 
1431                 let lifetime = reg.clean(cx);
1432                 let mut bounds = vec![];
1433 
1434                 for did in dids {
1435                     let empty = cx.tcx.intern_substs(&[]);
1436                     let path = external_path(cx, did, false, vec![], empty);
1437                     inline::record_extern_fqn(cx, did, ItemType::Trait);
1438                     let bound = PolyTrait { trait_: path, generic_params: Vec::new() };
1439                     bounds.push(bound);
1440                 }
1441 
1442                 let mut bindings = vec![];
1443                 for pb in obj.projection_bounds() {
1444                     bindings.push(TypeBinding {
1445                         name: cx.tcx.associated_item(pb.item_def_id()).ident.name,
1446                         kind: TypeBindingKind::Equality { ty: pb.skip_binder().ty.clean(cx) },
1447                     });
1448                 }
1449 
1450                 let path = external_path(cx, did, false, bindings, substs);
1451                 bounds.insert(0, PolyTrait { trait_: path, generic_params: Vec::new() });
1452 
1453                 DynTrait(bounds, lifetime)
1454             }
1455             ty::Tuple(t) => Tuple(t.iter().map(|t| t.expect_ty().clean(cx)).collect()),
1456 
1457             ty::Projection(ref data) => data.clean(cx),
1458 
1459             ty::Param(ref p) => {
1460                 if let Some(bounds) = cx.impl_trait_bounds.remove(&p.index.into()) {
1461                     ImplTrait(bounds)
1462                 } else {
1463                     Generic(p.name)
1464                 }
1465             }
1466 
1467             ty::Opaque(def_id, substs) => {
1468                 // Grab the "TraitA + TraitB" from `impl TraitA + TraitB`,
1469                 // by looking up the bounds associated with the def_id.
1470                 let substs = cx.tcx.lift(substs).expect("Opaque lift failed");
1471                 let bounds = cx
1472                     .tcx
1473                     .explicit_item_bounds(def_id)
1474                     .iter()
1475                     .map(|(bound, _)| bound.subst(cx.tcx, substs))
1476                     .collect::<Vec<_>>();
1477                 let mut regions = vec![];
1478                 let mut has_sized = false;
1479                 let mut bounds = bounds
1480                     .iter()
1481                     .filter_map(|bound| {
1482                         let bound_predicate = bound.kind();
1483                         let trait_ref = match bound_predicate.skip_binder() {
1484                             ty::PredicateKind::Trait(tr) => bound_predicate.rebind(tr.trait_ref),
1485                             ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(_ty, reg)) => {
1486                                 if let Some(r) = reg.clean(cx) {
1487                                     regions.push(GenericBound::Outlives(r));
1488                                 }
1489                                 return None;
1490                             }
1491                             _ => return None,
1492                         };
1493 
1494                         if let Some(sized) = cx.tcx.lang_items().sized_trait() {
1495                             if trait_ref.def_id() == sized {
1496                                 has_sized = true;
1497                                 return None;
1498                             }
1499                         }
1500 
1501                         let bounds: Vec<_> = bounds
1502                             .iter()
1503                             .filter_map(|bound| {
1504                                 if let ty::PredicateKind::Projection(proj) =
1505                                     bound.kind().skip_binder()
1506                                 {
1507                                     if proj.projection_ty.trait_ref(cx.tcx)
1508                                         == trait_ref.skip_binder()
1509                                     {
1510                                         Some(TypeBinding {
1511                                             name: cx
1512                                                 .tcx
1513                                                 .associated_item(proj.projection_ty.item_def_id)
1514                                                 .ident
1515                                                 .name,
1516                                             kind: TypeBindingKind::Equality {
1517                                                 ty: proj.ty.clean(cx),
1518                                             },
1519                                         })
1520                                     } else {
1521                                         None
1522                                     }
1523                                 } else {
1524                                     None
1525                                 }
1526                             })
1527                             .collect();
1528 
1529                         Some((trait_ref, &bounds[..]).clean(cx))
1530                     })
1531                     .collect::<Vec<_>>();
1532                 bounds.extend(regions);
1533                 if !has_sized && !bounds.is_empty() {
1534                     bounds.insert(0, GenericBound::maybe_sized(cx));
1535                 }
1536                 ImplTrait(bounds)
1537             }
1538 
1539             ty::Closure(..) | ty::Generator(..) => Tuple(vec![]), // FIXME(pcwalton)
1540 
1541             ty::Bound(..) => panic!("Bound"),
1542             ty::Placeholder(..) => panic!("Placeholder"),
1543             ty::GeneratorWitness(..) => panic!("GeneratorWitness"),
1544             ty::Infer(..) => panic!("Infer"),
1545             ty::Error(_) => panic!("Error"),
1546         }
1547     }
1548 }
1549 
1550 impl<'tcx> Clean<Constant> for ty::Const<'tcx> {
clean(&self, cx: &mut DocContext<'_>) -> Constant1551     fn clean(&self, cx: &mut DocContext<'_>) -> Constant {
1552         // FIXME: instead of storing the stringified expression, store `self` directly instead.
1553         Constant {
1554             type_: self.ty.clean(cx),
1555             kind: ConstantKind::TyConst { expr: self.to_string() },
1556         }
1557     }
1558 }
1559 
1560 impl Clean<Item> for hir::FieldDef<'_> {
clean(&self, cx: &mut DocContext<'_>) -> Item1561     fn clean(&self, cx: &mut DocContext<'_>) -> Item {
1562         let def_id = cx.tcx.hir().local_def_id(self.hir_id).to_def_id();
1563         clean_field(def_id, self.ident.name, self.ty.clean(cx), cx)
1564     }
1565 }
1566 
1567 impl Clean<Item> for ty::FieldDef {
clean(&self, cx: &mut DocContext<'_>) -> Item1568     fn clean(&self, cx: &mut DocContext<'_>) -> Item {
1569         clean_field(self.did, self.ident.name, cx.tcx.type_of(self.did).clean(cx), cx)
1570     }
1571 }
1572 
clean_field(def_id: DefId, name: Symbol, ty: Type, cx: &mut DocContext<'_>) -> Item1573 fn clean_field(def_id: DefId, name: Symbol, ty: Type, cx: &mut DocContext<'_>) -> Item {
1574     let what_rustc_thinks =
1575         Item::from_def_id_and_parts(def_id, Some(name), StructFieldItem(ty), cx);
1576     if is_field_vis_inherited(cx.tcx, def_id) {
1577         // Variant fields inherit their enum's visibility.
1578         Item { visibility: Visibility::Inherited, ..what_rustc_thinks }
1579     } else {
1580         what_rustc_thinks
1581     }
1582 }
1583 
is_field_vis_inherited(tcx: TyCtxt<'_>, def_id: DefId) -> bool1584 fn is_field_vis_inherited(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
1585     let parent = tcx
1586         .parent(def_id)
1587         .expect("is_field_vis_inherited can only be called on struct or variant fields");
1588     match tcx.def_kind(parent) {
1589         DefKind::Struct | DefKind::Union => false,
1590         DefKind::Variant => true,
1591         // FIXME: what about DefKind::Ctor?
1592         parent_kind => panic!("unexpected parent kind: {:?}", parent_kind),
1593     }
1594 }
1595 
1596 impl Clean<Visibility> for ty::Visibility {
clean(&self, _cx: &mut DocContext<'_>) -> Visibility1597     fn clean(&self, _cx: &mut DocContext<'_>) -> Visibility {
1598         match *self {
1599             ty::Visibility::Public => Visibility::Public,
1600             // NOTE: this is not quite right: `ty` uses `Invisible` to mean 'private',
1601             // while rustdoc really does mean inherited. That means that for enum variants, such as
1602             // `pub enum E { V }`, `V` will be marked as `Public` by `ty`, but as `Inherited` by rustdoc.
1603             // Various parts of clean override `tcx.visibility` explicitly to make sure this distinction is captured.
1604             ty::Visibility::Invisible => Visibility::Inherited,
1605             ty::Visibility::Restricted(module) => Visibility::Restricted(module),
1606         }
1607     }
1608 }
1609 
1610 impl Clean<VariantStruct> for rustc_hir::VariantData<'_> {
clean(&self, cx: &mut DocContext<'_>) -> VariantStruct1611     fn clean(&self, cx: &mut DocContext<'_>) -> VariantStruct {
1612         VariantStruct {
1613             struct_type: CtorKind::from_hir(self),
1614             fields: self.fields().iter().map(|x| x.clean(cx)).collect(),
1615             fields_stripped: false,
1616         }
1617     }
1618 }
1619 
1620 impl Clean<Vec<Item>> for hir::VariantData<'_> {
clean(&self, cx: &mut DocContext<'_>) -> Vec<Item>1621     fn clean(&self, cx: &mut DocContext<'_>) -> Vec<Item> {
1622         self.fields().iter().map(|x| x.clean(cx)).collect()
1623     }
1624 }
1625 
1626 impl Clean<Item> for ty::VariantDef {
clean(&self, cx: &mut DocContext<'_>) -> Item1627     fn clean(&self, cx: &mut DocContext<'_>) -> Item {
1628         let kind = match self.ctor_kind {
1629             CtorKind::Const => Variant::CLike,
1630             CtorKind::Fn => {
1631                 Variant::Tuple(self.fields.iter().map(|field| field.clean(cx)).collect())
1632             }
1633             CtorKind::Fictive => Variant::Struct(VariantStruct {
1634                 struct_type: CtorKind::Fictive,
1635                 fields_stripped: false,
1636                 fields: self.fields.iter().map(|field| field.clean(cx)).collect(),
1637             }),
1638         };
1639         let what_rustc_thinks =
1640             Item::from_def_id_and_parts(self.def_id, Some(self.ident.name), VariantItem(kind), cx);
1641         // don't show `pub` for variants, which always inherit visibility
1642         Item { visibility: Inherited, ..what_rustc_thinks }
1643     }
1644 }
1645 
1646 impl Clean<Variant> for hir::VariantData<'_> {
clean(&self, cx: &mut DocContext<'_>) -> Variant1647     fn clean(&self, cx: &mut DocContext<'_>) -> Variant {
1648         match self {
1649             hir::VariantData::Struct(..) => Variant::Struct(self.clean(cx)),
1650             hir::VariantData::Tuple(..) => Variant::Tuple(self.clean(cx)),
1651             hir::VariantData::Unit(..) => Variant::CLike,
1652         }
1653     }
1654 }
1655 
1656 impl Clean<Path> for hir::Path<'_> {
clean(&self, cx: &mut DocContext<'_>) -> Path1657     fn clean(&self, cx: &mut DocContext<'_>) -> Path {
1658         Path { res: self.res, segments: self.segments.iter().map(|x| x.clean(cx)).collect() }
1659     }
1660 }
1661 
1662 impl Clean<GenericArgs> for hir::GenericArgs<'_> {
clean(&self, cx: &mut DocContext<'_>) -> GenericArgs1663     fn clean(&self, cx: &mut DocContext<'_>) -> GenericArgs {
1664         if self.parenthesized {
1665             let output = self.bindings[0].ty().clean(cx);
1666             let output =
1667                 if output != Type::Tuple(Vec::new()) { Some(Box::new(output)) } else { None };
1668             let inputs = self.inputs().iter().map(|x| x.clean(cx)).collect();
1669             GenericArgs::Parenthesized { inputs, output }
1670         } else {
1671             let args = self
1672                 .args
1673                 .iter()
1674                 .map(|arg| match arg {
1675                     hir::GenericArg::Lifetime(lt) if !lt.is_elided() => {
1676                         GenericArg::Lifetime(lt.clean(cx))
1677                     }
1678                     hir::GenericArg::Lifetime(_) => GenericArg::Lifetime(Lifetime::elided()),
1679                     hir::GenericArg::Type(ty) => GenericArg::Type(ty.clean(cx)),
1680                     hir::GenericArg::Const(ct) => GenericArg::Const(Box::new(ct.clean(cx))),
1681                     hir::GenericArg::Infer(_inf) => GenericArg::Infer,
1682                 })
1683                 .collect();
1684             let bindings = self.bindings.iter().map(|x| x.clean(cx)).collect();
1685             GenericArgs::AngleBracketed { args, bindings }
1686         }
1687     }
1688 }
1689 
1690 impl Clean<PathSegment> for hir::PathSegment<'_> {
clean(&self, cx: &mut DocContext<'_>) -> PathSegment1691     fn clean(&self, cx: &mut DocContext<'_>) -> PathSegment {
1692         PathSegment { name: self.ident.name, args: self.args().clean(cx) }
1693     }
1694 }
1695 
1696 impl Clean<BareFunctionDecl> for hir::BareFnTy<'_> {
clean(&self, cx: &mut DocContext<'_>) -> BareFunctionDecl1697     fn clean(&self, cx: &mut DocContext<'_>) -> BareFunctionDecl {
1698         let (generic_params, decl) = enter_impl_trait(cx, |cx| {
1699             // NOTE: generics must be cleaned before args
1700             let generic_params = self.generic_params.iter().map(|x| x.clean(cx)).collect();
1701             let args = (self.decl.inputs, self.param_names).clean(cx);
1702             let decl = clean_fn_decl_with_args(cx, self.decl, args);
1703             (generic_params, decl)
1704         });
1705         BareFunctionDecl { unsafety: self.unsafety, abi: self.abi, decl, generic_params }
1706     }
1707 }
1708 
1709 impl Clean<Vec<Item>> for (&hir::Item<'_>, Option<Symbol>) {
clean(&self, cx: &mut DocContext<'_>) -> Vec<Item>1710     fn clean(&self, cx: &mut DocContext<'_>) -> Vec<Item> {
1711         use hir::ItemKind;
1712 
1713         let (item, renamed) = self;
1714         let def_id = item.def_id.to_def_id();
1715         let mut name = renamed.unwrap_or_else(|| cx.tcx.hir().name(item.hir_id()));
1716         cx.with_param_env(def_id, |cx| {
1717             let kind = match item.kind {
1718                 ItemKind::Static(ty, mutability, body_id) => {
1719                     StaticItem(Static { type_: ty.clean(cx), mutability, expr: Some(body_id) })
1720                 }
1721                 ItemKind::Const(ty, body_id) => ConstantItem(Constant {
1722                     type_: ty.clean(cx),
1723                     kind: ConstantKind::Local { body: body_id, def_id },
1724                 }),
1725                 ItemKind::OpaqueTy(ref ty) => OpaqueTyItem(OpaqueTy {
1726                     bounds: ty.bounds.iter().map(|x| x.clean(cx)).collect(),
1727                     generics: ty.generics.clean(cx),
1728                 }),
1729                 ItemKind::TyAlias(hir_ty, ref generics) => {
1730                     let rustdoc_ty = hir_ty.clean(cx);
1731                     let ty = hir_ty_to_ty(cx.tcx, hir_ty).clean(cx);
1732                     TypedefItem(
1733                         Typedef {
1734                             type_: rustdoc_ty,
1735                             generics: generics.clean(cx),
1736                             item_type: Some(ty),
1737                         },
1738                         false,
1739                     )
1740                 }
1741                 ItemKind::Enum(ref def, ref generics) => EnumItem(Enum {
1742                     variants: def.variants.iter().map(|v| v.clean(cx)).collect(),
1743                     generics: generics.clean(cx),
1744                     variants_stripped: false,
1745                 }),
1746                 ItemKind::TraitAlias(ref generics, bounds) => TraitAliasItem(TraitAlias {
1747                     generics: generics.clean(cx),
1748                     bounds: bounds.iter().map(|x| x.clean(cx)).collect(),
1749                 }),
1750                 ItemKind::Union(ref variant_data, ref generics) => UnionItem(Union {
1751                     generics: generics.clean(cx),
1752                     fields: variant_data.fields().iter().map(|x| x.clean(cx)).collect(),
1753                     fields_stripped: false,
1754                 }),
1755                 ItemKind::Struct(ref variant_data, ref generics) => StructItem(Struct {
1756                     struct_type: CtorKind::from_hir(variant_data),
1757                     generics: generics.clean(cx),
1758                     fields: variant_data.fields().iter().map(|x| x.clean(cx)).collect(),
1759                     fields_stripped: false,
1760                 }),
1761                 ItemKind::Impl(ref impl_) => return clean_impl(impl_, item.hir_id(), cx),
1762                 // proc macros can have a name set by attributes
1763                 ItemKind::Fn(ref sig, ref generics, body_id) => {
1764                     clean_fn_or_proc_macro(item, sig, generics, body_id, &mut name, cx)
1765                 }
1766                 ItemKind::Macro(ref macro_def) => {
1767                     let ty_vis = cx.tcx.visibility(def_id).clean(cx);
1768                     MacroItem(Macro {
1769                         source: display_macro_source(cx, name, macro_def, def_id, ty_vis),
1770                     })
1771                 }
1772                 ItemKind::Trait(is_auto, unsafety, ref generics, bounds, item_ids) => {
1773                     let items = item_ids
1774                         .iter()
1775                         .map(|ti| cx.tcx.hir().trait_item(ti.id).clean(cx))
1776                         .collect();
1777                     TraitItem(Trait {
1778                         unsafety,
1779                         items,
1780                         generics: generics.clean(cx),
1781                         bounds: bounds.iter().map(|x| x.clean(cx)).collect(),
1782                         is_auto: is_auto.clean(cx),
1783                     })
1784                 }
1785                 ItemKind::ExternCrate(orig_name) => {
1786                     return clean_extern_crate(item, name, orig_name, cx);
1787                 }
1788                 ItemKind::Use(path, kind) => {
1789                     return clean_use_statement(item, name, path, kind, cx);
1790                 }
1791                 _ => unreachable!("not yet converted"),
1792             };
1793 
1794             vec![Item::from_def_id_and_parts(def_id, Some(name), kind, cx)]
1795         })
1796     }
1797 }
1798 
1799 impl Clean<Item> for hir::Variant<'_> {
clean(&self, cx: &mut DocContext<'_>) -> Item1800     fn clean(&self, cx: &mut DocContext<'_>) -> Item {
1801         let kind = VariantItem(self.data.clean(cx));
1802         let what_rustc_thinks =
1803             Item::from_hir_id_and_parts(self.id, Some(self.ident.name), kind, cx);
1804         // don't show `pub` for variants, which are always public
1805         Item { visibility: Inherited, ..what_rustc_thinks }
1806     }
1807 }
1808 
clean_impl(impl_: &hir::Impl<'_>, hir_id: hir::HirId, cx: &mut DocContext<'_>) -> Vec<Item>1809 fn clean_impl(impl_: &hir::Impl<'_>, hir_id: hir::HirId, cx: &mut DocContext<'_>) -> Vec<Item> {
1810     let tcx = cx.tcx;
1811     let mut ret = Vec::new();
1812     let trait_ = impl_.of_trait.as_ref().map(|t| t.clean(cx));
1813     let items =
1814         impl_.items.iter().map(|ii| tcx.hir().impl_item(ii.id).clean(cx)).collect::<Vec<_>>();
1815     let def_id = tcx.hir().local_def_id(hir_id);
1816 
1817     // If this impl block is an implementation of the Deref trait, then we
1818     // need to try inlining the target's inherent impl blocks as well.
1819     if trait_.as_ref().map(|t| t.def_id()) == tcx.lang_items().deref_trait() {
1820         build_deref_target_impls(cx, &items, &mut ret);
1821     }
1822 
1823     let for_ = impl_.self_ty.clean(cx);
1824     let type_alias = for_.def_id(&cx.cache).and_then(|did| match tcx.def_kind(did) {
1825         DefKind::TyAlias => Some(tcx.type_of(did).clean(cx)),
1826         _ => None,
1827     });
1828     let mut make_item = |trait_: Option<Path>, for_: Type, items: Vec<Item>| {
1829         let kind = ImplItem(Impl {
1830             unsafety: impl_.unsafety,
1831             generics: impl_.generics.clean(cx),
1832             trait_,
1833             for_,
1834             items,
1835             polarity: tcx.impl_polarity(def_id),
1836             kind: ImplKind::Normal,
1837         });
1838         Item::from_hir_id_and_parts(hir_id, None, kind, cx)
1839     };
1840     if let Some(type_alias) = type_alias {
1841         ret.push(make_item(trait_.clone(), type_alias, items.clone()));
1842     }
1843     ret.push(make_item(trait_, for_, items));
1844     ret
1845 }
1846 
clean_extern_crate( krate: &hir::Item<'_>, name: Symbol, orig_name: Option<Symbol>, cx: &mut DocContext<'_>, ) -> Vec<Item>1847 fn clean_extern_crate(
1848     krate: &hir::Item<'_>,
1849     name: Symbol,
1850     orig_name: Option<Symbol>,
1851     cx: &mut DocContext<'_>,
1852 ) -> Vec<Item> {
1853     // this is the ID of the `extern crate` statement
1854     let cnum = cx.tcx.extern_mod_stmt_cnum(krate.def_id).unwrap_or(LOCAL_CRATE);
1855     // this is the ID of the crate itself
1856     let crate_def_id = DefId { krate: cnum, index: CRATE_DEF_INDEX };
1857     let attrs = cx.tcx.hir().attrs(krate.hir_id());
1858     let ty_vis = cx.tcx.visibility(krate.def_id);
1859     let please_inline = ty_vis.is_public()
1860         && attrs.iter().any(|a| {
1861             a.has_name(sym::doc)
1862                 && match a.meta_item_list() {
1863                     Some(l) => attr::list_contains_name(&l, sym::inline),
1864                     None => false,
1865                 }
1866         });
1867 
1868     if please_inline {
1869         let mut visited = FxHashSet::default();
1870 
1871         let res = Res::Def(DefKind::Mod, crate_def_id);
1872 
1873         if let Some(items) = inline::try_inline(
1874             cx,
1875             cx.tcx.parent_module(krate.hir_id()).to_def_id(),
1876             Some(krate.def_id.to_def_id()),
1877             res,
1878             name,
1879             Some(attrs),
1880             &mut visited,
1881         ) {
1882             return items;
1883         }
1884     }
1885 
1886     // FIXME: using `from_def_id_and_kind` breaks `rustdoc/masked` for some reason
1887     vec![Item {
1888         name: Some(name),
1889         attrs: box attrs.clean(cx),
1890         def_id: crate_def_id.into(),
1891         visibility: ty_vis.clean(cx),
1892         kind: box ExternCrateItem { src: orig_name },
1893         cfg: attrs.cfg(cx.tcx, &cx.cache.hidden_cfg),
1894     }]
1895 }
1896 
clean_use_statement( import: &hir::Item<'_>, name: Symbol, path: &hir::Path<'_>, kind: hir::UseKind, cx: &mut DocContext<'_>, ) -> Vec<Item>1897 fn clean_use_statement(
1898     import: &hir::Item<'_>,
1899     name: Symbol,
1900     path: &hir::Path<'_>,
1901     kind: hir::UseKind,
1902     cx: &mut DocContext<'_>,
1903 ) -> Vec<Item> {
1904     // We need this comparison because some imports (for std types for example)
1905     // are "inserted" as well but directly by the compiler and they should not be
1906     // taken into account.
1907     if import.span.ctxt().outer_expn_data().kind == ExpnKind::AstPass(AstPass::StdImports) {
1908         return Vec::new();
1909     }
1910 
1911     let visibility = cx.tcx.visibility(import.def_id);
1912     let attrs = cx.tcx.hir().attrs(import.hir_id());
1913     let inline_attr = attrs.lists(sym::doc).get_word_attr(sym::inline);
1914     let pub_underscore = visibility.is_public() && name == kw::Underscore;
1915     let current_mod = cx.tcx.parent_module_from_def_id(import.def_id);
1916 
1917     // The parent of the module in which this import resides. This
1918     // is the same as `current_mod` if that's already the top
1919     // level module.
1920     let parent_mod = cx.tcx.parent_module_from_def_id(current_mod);
1921 
1922     // This checks if the import can be seen from a higher level module.
1923     // In other words, it checks if the visibility is the equivalent of
1924     // `pub(super)` or higher. If the current module is the top level
1925     // module, there isn't really a parent module, which makes the results
1926     // meaningless. In this case, we make sure the answer is `false`.
1927     let is_visible_from_parent_mod = visibility.is_accessible_from(parent_mod.to_def_id(), cx.tcx)
1928         && !current_mod.is_top_level_module();
1929 
1930     if pub_underscore {
1931         if let Some(ref inline) = inline_attr {
1932             rustc_errors::struct_span_err!(
1933                 cx.tcx.sess,
1934                 inline.span(),
1935                 E0780,
1936                 "anonymous imports cannot be inlined"
1937             )
1938             .span_label(import.span, "anonymous import")
1939             .emit();
1940         }
1941     }
1942 
1943     // We consider inlining the documentation of `pub use` statements, but we
1944     // forcefully don't inline if this is not public or if the
1945     // #[doc(no_inline)] attribute is present.
1946     // Don't inline doc(hidden) imports so they can be stripped at a later stage.
1947     let mut denied = !(visibility.is_public()
1948         || (cx.render_options.document_private && is_visible_from_parent_mod))
1949         || pub_underscore
1950         || attrs.iter().any(|a| {
1951             a.has_name(sym::doc)
1952                 && match a.meta_item_list() {
1953                     Some(l) => {
1954                         attr::list_contains_name(&l, sym::no_inline)
1955                             || attr::list_contains_name(&l, sym::hidden)
1956                     }
1957                     None => false,
1958                 }
1959         });
1960 
1961     // Also check whether imports were asked to be inlined, in case we're trying to re-export a
1962     // crate in Rust 2018+
1963     let path = path.clean(cx);
1964     let inner = if kind == hir::UseKind::Glob {
1965         if !denied {
1966             let mut visited = FxHashSet::default();
1967             if let Some(items) = inline::try_inline_glob(cx, path.res, &mut visited) {
1968                 return items;
1969             }
1970         }
1971         Import::new_glob(resolve_use_source(cx, path), true)
1972     } else {
1973         if inline_attr.is_none() {
1974             if let Res::Def(DefKind::Mod, did) = path.res {
1975                 if !did.is_local() && did.index == CRATE_DEF_INDEX {
1976                     // if we're `pub use`ing an extern crate root, don't inline it unless we
1977                     // were specifically asked for it
1978                     denied = true;
1979                 }
1980             }
1981         }
1982         if !denied {
1983             let mut visited = FxHashSet::default();
1984             let import_def_id = import.def_id.to_def_id();
1985 
1986             if let Some(mut items) = inline::try_inline(
1987                 cx,
1988                 cx.tcx.parent_module(import.hir_id()).to_def_id(),
1989                 Some(import_def_id),
1990                 path.res,
1991                 name,
1992                 Some(attrs),
1993                 &mut visited,
1994             ) {
1995                 items.push(Item::from_def_id_and_parts(
1996                     import_def_id,
1997                     None,
1998                     ImportItem(Import::new_simple(name, resolve_use_source(cx, path), false)),
1999                     cx,
2000                 ));
2001                 return items;
2002             }
2003         }
2004         Import::new_simple(name, resolve_use_source(cx, path), true)
2005     };
2006 
2007     vec![Item::from_def_id_and_parts(import.def_id.to_def_id(), None, ImportItem(inner), cx)]
2008 }
2009 
2010 impl Clean<Item> for (&hir::ForeignItem<'_>, Option<Symbol>) {
clean(&self, cx: &mut DocContext<'_>) -> Item2011     fn clean(&self, cx: &mut DocContext<'_>) -> Item {
2012         let (item, renamed) = self;
2013         let def_id = item.def_id.to_def_id();
2014         cx.with_param_env(def_id, |cx| {
2015             let kind = match item.kind {
2016                 hir::ForeignItemKind::Fn(decl, names, ref generics) => {
2017                     let abi = cx.tcx.hir().get_foreign_abi(item.hir_id());
2018                     let (generics, decl) = enter_impl_trait(cx, |cx| {
2019                         // NOTE: generics must be cleaned before args
2020                         let generics = generics.clean(cx);
2021                         let args = (decl.inputs, names).clean(cx);
2022                         let decl = clean_fn_decl_with_args(cx, decl, args);
2023                         (generics, decl)
2024                     });
2025                     ForeignFunctionItem(Function {
2026                         decl,
2027                         generics,
2028                         header: hir::FnHeader {
2029                             unsafety: if abi == Abi::RustIntrinsic {
2030                                 intrinsic_operation_unsafety(item.ident.name)
2031                             } else {
2032                                 hir::Unsafety::Unsafe
2033                             },
2034                             abi,
2035                             constness: hir::Constness::NotConst,
2036                             asyncness: hir::IsAsync::NotAsync,
2037                         },
2038                     })
2039                 }
2040                 hir::ForeignItemKind::Static(ref ty, mutability) => {
2041                     ForeignStaticItem(Static { type_: ty.clean(cx), mutability, expr: None })
2042                 }
2043                 hir::ForeignItemKind::Type => ForeignTypeItem,
2044             };
2045 
2046             Item::from_hir_id_and_parts(
2047                 item.hir_id(),
2048                 Some(renamed.unwrap_or(item.ident.name)),
2049                 kind,
2050                 cx,
2051             )
2052         })
2053     }
2054 }
2055 
2056 impl Clean<TypeBinding> for hir::TypeBinding<'_> {
clean(&self, cx: &mut DocContext<'_>) -> TypeBinding2057     fn clean(&self, cx: &mut DocContext<'_>) -> TypeBinding {
2058         TypeBinding { name: self.ident.name, kind: self.kind.clean(cx) }
2059     }
2060 }
2061 
2062 impl Clean<TypeBindingKind> for hir::TypeBindingKind<'_> {
clean(&self, cx: &mut DocContext<'_>) -> TypeBindingKind2063     fn clean(&self, cx: &mut DocContext<'_>) -> TypeBindingKind {
2064         match *self {
2065             hir::TypeBindingKind::Equality { ref ty } => {
2066                 TypeBindingKind::Equality { ty: ty.clean(cx) }
2067             }
2068             hir::TypeBindingKind::Constraint { bounds } => {
2069                 TypeBindingKind::Constraint { bounds: bounds.iter().map(|b| b.clean(cx)).collect() }
2070             }
2071         }
2072     }
2073 }
2074