src/librustdoc/clean/mod.rs

   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 render_macro_matchers;
   9 mod simplify;
  10 crate mod types;
  11 crate mod utils;
  12
  13 use rustc_ast as ast;
  14 use rustc_attr as attr;
  15 use rustc_const_eval::const_eval::is_unstable_const_fn;
  16 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
  17 use rustc_hir as hir;
  18 use rustc_hir::def::{CtorKind, DefKind, Res};
  19 use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
  20 use rustc_infer::infer::region_constraints::{Constraint, RegionConstraintData};
  21 use rustc_middle::middle::resolve_lifetime as rl;
  22 use rustc_middle::ty::fold::TypeFolder;
  23 use rustc_middle::ty::subst::{InternalSubsts, Subst};
  24 use rustc_middle::ty::{self, AdtKind, DefIdTree, Lift, Ty, TyCtxt};
  25 use rustc_middle::{bug, span_bug};
  26 use rustc_span::hygiene::{AstPass, MacroKind};
  27 use rustc_span::symbol::{kw, sym, Ident, Symbol};
  28 use rustc_span::{self, ExpnKind};
  29 use rustc_target::spec::abi::Abi;
  30 use rustc_typeck::check::intrinsic::intrinsic_operation_unsafety;
  31 use rustc_typeck::hir_ty_to_ty;
  32
  33 use std::assert_matches::assert_matches;
  34 use std::collections::hash_map::Entry;
  35 use std::collections::BTreeMap;
  36 use std::default::Default;
  37 use std::hash::Hash;
  38 use std::{mem, vec};
  39
  40 use crate::core::{self, DocContext, ImplTraitParam};
  41 use crate::formats::item_type::ItemType;
  42 use crate::visit_ast::Module as DocModule;
  43
  44 use utils::*;
  45
  46 crate use self::types::*;
  47 crate use self::utils::{get_auto_trait_and_blanket_impls, krate, register_res};
  48
  49 crate trait Clean<T> {
  50     fn clean(&self, cx: &mut DocContext<'_>) -> T;
  51 }
  52
  53 impl Clean<Item> for DocModule<'_> {
  54     fn clean(&self, cx: &mut DocContext<'_>) -> Item {
  55         let mut items: Vec<Item> = vec![];
  56         items.extend(
  57             self.foreigns
  58                 .iter()
  59                 .map(|(item, renamed)| clean_maybe_renamed_foreign_item(cx, item, *renamed)),
  60         );
  61         items.extend(self.mods.iter().map(|x| x.clean(cx)));
  62         items.extend(
  63             self.items
  64                 .iter()
  65                 .flat_map(|(item, renamed)| clean_maybe_renamed_item(cx, item, *renamed)),
  66         );
  67
  68         // determine if we should display the inner contents or
  69         // the outer `mod` item for the source code.
  70
  71         let span = Span::new({
  72             let where_outer = self.where_outer(cx.tcx);
  73             let sm = cx.sess().source_map();
  74             let outer = sm.lookup_char_pos(where_outer.lo());
  75             let inner = sm.lookup_char_pos(self.where_inner.lo());
  76             if outer.file.start_pos == inner.file.start_pos {
  77                 // mod foo { ... }
  78                 where_outer
  79             } else {
  80                 // mod foo; (and a separate SourceFile for the contents)
  81                 self.where_inner
  82             }
  83         });
  84
  85         Item::from_hir_id_and_parts(
  86             self.id,
  87             Some(self.name),
  88             ModuleItem(Module { items, span }),
  89             cx,
  90         )
  91     }
  92 }
  93
  94 impl Clean<Attributes> for [ast::Attribute] {
  95     fn clean(&self, _cx: &mut DocContext<'_>) -> Attributes {
  96         Attributes::from_ast(self, None)
  97     }
  98 }
  99
 100 impl Clean<Option<GenericBound>> for hir::GenericBound<'_> {
 101     fn clean(&self, cx: &mut DocContext<'_>) -> Option<GenericBound> {
 102         Some(match *self {
 103             hir::GenericBound::Outlives(lt) => GenericBound::Outlives(lt.clean(cx)),
 104             hir::GenericBound::LangItemTrait(lang_item, span, _, generic_args) => {
 105                 let def_id = cx.tcx.require_lang_item(lang_item, Some(span));
 106
 107                 let trait_ref = ty::TraitRef::identity(cx.tcx, def_id).skip_binder();
 108
 109                 let generic_args = generic_args.clean(cx);
 110                 let bindings = match generic_args {
 111                     GenericArgs::AngleBracketed { bindings, .. } => bindings,
 112                     _ => bug!("clean: parenthesized `GenericBound::LangItemTrait`"),
 113                 };
 114
 115                 let trait_ = clean_trait_ref_with_bindings(cx, trait_ref, &bindings);
 116                 GenericBound::TraitBound(
 117                     PolyTrait { trait_, generic_params: vec![] },
 118                     hir::TraitBoundModifier::None,
 119                 )
 120             }
 121             hir::GenericBound::Trait(ref t, modifier) => {
 122                 // `T: ~const Drop` is not equivalent to `T: Drop`, and we don't currently document `~const` bounds
 123                 // because of its experimental status, so just don't show these.
 124                 if Some(t.trait_ref.trait_def_id().unwrap()) == cx.tcx.lang_items().drop_trait()
 125                     && hir::TraitBoundModifier::MaybeConst == modifier
 126                 {
 127                     return None;
 128                 }
 129                 GenericBound::TraitBound(t.clean(cx), modifier)
 130             }
 131         })
 132     }
 133 }
 134
 135 fn clean_trait_ref_with_bindings(
 136     cx: &mut DocContext<'_>,
 137     trait_ref: ty::TraitRef<'_>,
 138     bindings: &[TypeBinding],
 139 ) -> Path {
 140     let kind = cx.tcx.def_kind(trait_ref.def_id).into();
 141     if !matches!(kind, ItemType::Trait | ItemType::TraitAlias) {
 142         span_bug!(cx.tcx.def_span(trait_ref.def_id), "`TraitRef` had unexpected kind {:?}", kind);
 143     }
 144     inline::record_extern_fqn(cx, trait_ref.def_id, kind);
 145     let path = external_path(cx, trait_ref.def_id, true, bindings.to_vec(), trait_ref.substs);
 146
 147     debug!("ty::TraitRef\n  subst: {:?}\n", trait_ref.substs);
 148
 149     path
 150 }
 151
 152 impl Clean<Path> for ty::TraitRef<'_> {
 153     fn clean(&self, cx: &mut DocContext<'_>) -> Path {
 154         clean_trait_ref_with_bindings(cx, *self, &[])
 155     }
 156 }
 157
 158 fn clean_poly_trait_ref_with_bindings(
 159     cx: &mut DocContext<'_>,
 160     poly_trait_ref: ty::PolyTraitRef<'_>,
 161     bindings: &[TypeBinding],
 162 ) -> GenericBound {
 163     let poly_trait_ref = poly_trait_ref.lift_to_tcx(cx.tcx).unwrap();
 164
 165     // collect any late bound regions
 166     let late_bound_regions: Vec<_> = cx
 167         .tcx
 168         .collect_referenced_late_bound_regions(&poly_trait_ref)
 169         .into_iter()
 170         .filter_map(|br| match br {
 171             ty::BrNamed(_, name) => Some(GenericParamDef {
 172                 name,
 173                 kind: GenericParamDefKind::Lifetime { outlives: vec![] },
 174             }),
 175             _ => None,
 176         })
 177         .collect();
 178
 179     let trait_ = clean_trait_ref_with_bindings(cx, poly_trait_ref.skip_binder(), bindings);
 180     GenericBound::TraitBound(
 181         PolyTrait { trait_, generic_params: late_bound_regions },
 182         hir::TraitBoundModifier::None,
 183     )
 184 }
 185
 186 impl<'tcx> Clean<GenericBound> for ty::PolyTraitRef<'tcx> {
 187     fn clean(&self, cx: &mut DocContext<'_>) -> GenericBound {
 188         clean_poly_trait_ref_with_bindings(cx, *self, &[])
 189     }
 190 }
 191
 192 impl Clean<Lifetime> for hir::Lifetime {
 193     fn clean(&self, cx: &mut DocContext<'_>) -> Lifetime {
 194         let def = cx.tcx.named_region(self.hir_id);
 195         if let Some(
 196             rl::Region::EarlyBound(_, node_id, _)
 197             | rl::Region::LateBound(_, _, node_id, _)
 198             | rl::Region::Free(_, node_id),
 199         ) = def
 200         {
 201             if let Some(lt) = cx.substs.get(&node_id).and_then(|p| p.as_lt()).cloned() {
 202                 return lt;
 203             }
 204         }
 205         Lifetime(self.name.ident().name)
 206     }
 207 }
 208
 209 impl Clean<Constant> for hir::ConstArg {
 210     fn clean(&self, cx: &mut DocContext<'_>) -> Constant {
 211         Constant {
 212             type_: cx
 213                 .tcx
 214                 .type_of(cx.tcx.hir().body_owner_def_id(self.value.body).to_def_id())
 215                 .clean(cx),
 216             kind: ConstantKind::Anonymous { body: self.value.body },
 217         }
 218     }
 219 }
 220
 221 impl Clean<Option<Lifetime>> for ty::RegionKind {
 222     fn clean(&self, _cx: &mut DocContext<'_>) -> Option<Lifetime> {
 223         match *self {
 224             ty::ReStatic => Some(Lifetime::statik()),
 225             ty::ReLateBound(_, ty::BoundRegion { kind: ty::BrNamed(_, name), .. }) => {
 226                 Some(Lifetime(name))
 227             }
 228             ty::ReEarlyBound(ref data) => Some(Lifetime(data.name)),
 229
 230             ty::ReLateBound(..)
 231             | ty::ReFree(..)
 232             | ty::ReVar(..)
 233             | ty::RePlaceholder(..)
 234             | ty::ReEmpty(_)
 235             | ty::ReErased => {
 236                 debug!("cannot clean region {:?}", self);
 237                 None
 238             }
 239         }
 240     }
 241 }
 242
 243 impl Clean<WherePredicate> for hir::WherePredicate<'_> {
 244     fn clean(&self, cx: &mut DocContext<'_>) -> WherePredicate {
 245         match *self {
 246             hir::WherePredicate::BoundPredicate(ref wbp) => {
 247                 let bound_params = wbp
 248                     .bound_generic_params
 249                     .into_iter()
 250                     .map(|param| {
 251                         // Higher-ranked params must be lifetimes.
 252                         // Higher-ranked lifetimes can't have bounds.
 253                         assert_matches!(
 254                             param,
 255                             hir::GenericParam {
 256                                 kind: hir::GenericParamKind::Lifetime { .. },
 257                                 bounds: [],
 258                                 ..
 259                             }
 260                         );
 261                         Lifetime(param.name.ident().name)
 262                     })
 263                     .collect();
 264                 WherePredicate::BoundPredicate {
 265                     ty: wbp.bounded_ty.clean(cx),
 266                     bounds: wbp.bounds.iter().filter_map(|x| x.clean(cx)).collect(),
 267                     bound_params,
 268                 }
 269             }
 270
 271             hir::WherePredicate::RegionPredicate(ref wrp) => WherePredicate::RegionPredicate {
 272                 lifetime: wrp.lifetime.clean(cx),
 273                 bounds: wrp.bounds.iter().filter_map(|x| x.clean(cx)).collect(),
 274             },
 275
 276             hir::WherePredicate::EqPredicate(ref wrp) => WherePredicate::EqPredicate {
 277                 lhs: wrp.lhs_ty.clean(cx),
 278                 rhs: wrp.rhs_ty.clean(cx).into(),
 279             },
 280         }
 281     }
 282 }
 283
 284 impl<'a> Clean<Option<WherePredicate>> for ty::Predicate<'a> {
 285     fn clean(&self, cx: &mut DocContext<'_>) -> Option<WherePredicate> {
 286         let bound_predicate = self.kind();
 287         match bound_predicate.skip_binder() {
 288             ty::PredicateKind::Trait(pred) => bound_predicate.rebind(pred).clean(cx),
 289             ty::PredicateKind::RegionOutlives(pred) => pred.clean(cx),
 290             ty::PredicateKind::TypeOutlives(pred) => pred.clean(cx),
 291             ty::PredicateKind::Projection(pred) => Some(pred.clean(cx)),
 292             ty::PredicateKind::ConstEvaluatable(..) => None,
 293
 294             ty::PredicateKind::Subtype(..)
 295             | ty::PredicateKind::Coerce(..)
 296             | ty::PredicateKind::WellFormed(..)
 297             | ty::PredicateKind::ObjectSafe(..)
 298             | ty::PredicateKind::ClosureKind(..)
 299             | ty::PredicateKind::ConstEquate(..)
 300             | ty::PredicateKind::TypeWellFormedFromEnv(..) => panic!("not user writable"),
 301         }
 302     }
 303 }
 304
 305 impl<'a> Clean<Option<WherePredicate>> for ty::PolyTraitPredicate<'a> {
 306     fn clean(&self, cx: &mut DocContext<'_>) -> Option<WherePredicate> {
 307         // `T: ~const Drop` is not equivalent to `T: Drop`, and we don't currently document `~const` bounds
 308         // because of its experimental status, so just don't show these.
 309         if self.skip_binder().constness == ty::BoundConstness::ConstIfConst
 310             && Some(self.skip_binder().trait_ref.def_id) == cx.tcx.lang_items().drop_trait()
 311         {
 312             return None;
 313         }
 314
 315         let poly_trait_ref = self.map_bound(|pred| pred.trait_ref);
 316         Some(WherePredicate::BoundPredicate {
 317             ty: poly_trait_ref.skip_binder().self_ty().clean(cx),
 318             bounds: vec![poly_trait_ref.clean(cx)],
 319             bound_params: Vec::new(),
 320         })
 321     }
 322 }
 323
 324 impl<'tcx> Clean<Option<WherePredicate>>
 325     for ty::OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>
 326 {
 327     fn clean(&self, cx: &mut DocContext<'_>) -> Option<WherePredicate> {
 328         let ty::OutlivesPredicate(a, b) = self;
 329
 330         if let (ty::ReEmpty(_), ty::ReEmpty(_)) = (a, b) {
 331             return None;
 332         }
 333
 334         Some(WherePredicate::RegionPredicate {
 335             lifetime: a.clean(cx).expect("failed to clean lifetime"),
 336             bounds: vec![GenericBound::Outlives(b.clean(cx).expect("failed to clean bounds"))],
 337         })
 338     }
 339 }
 340
 341 impl<'tcx> Clean<Option<WherePredicate>> for ty::OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>> {
 342     fn clean(&self, cx: &mut DocContext<'_>) -> Option<WherePredicate> {
 343         let ty::OutlivesPredicate(ty, lt) = self;
 344
 345         if let ty::ReEmpty(_) = lt {
 346             return None;
 347         }
 348
 349         Some(WherePredicate::BoundPredicate {
 350             ty: ty.clean(cx),
 351             bounds: vec![GenericBound::Outlives(lt.clean(cx).expect("failed to clean lifetimes"))],
 352             bound_params: Vec::new(),
 353         })
 354     }
 355 }
 356
 357 impl<'tcx> Clean<Term> for ty::Term<'tcx> {
 358     fn clean(&self, cx: &mut DocContext<'_>) -> Term {
 359         match self {
 360             ty::Term::Ty(ty) => Term::Type(ty.clean(cx)),
 361             ty::Term::Const(c) => Term::Constant(c.clean(cx)),
 362         }
 363     }
 364 }
 365
 366 impl<'tcx> Clean<Term> for hir::Term<'tcx> {
 367     fn clean(&self, cx: &mut DocContext<'_>) -> Term {
 368         match self {
 369             hir::Term::Ty(ty) => Term::Type(ty.clean(cx)),
 370             hir::Term::Const(c) => {
 371                 let def_id = cx.tcx.hir().local_def_id(c.hir_id);
 372                 Term::Constant(ty::Const::from_anon_const(cx.tcx, def_id).clean(cx))
 373             }
 374         }
 375     }
 376 }
 377
 378 impl<'tcx> Clean<WherePredicate> for ty::ProjectionPredicate<'tcx> {
 379     fn clean(&self, cx: &mut DocContext<'_>) -> WherePredicate {
 380         let ty::ProjectionPredicate { projection_ty, term } = self;
 381         WherePredicate::EqPredicate { lhs: projection_ty.clean(cx), rhs: term.clean(cx) }
 382     }
 383 }
 384
 385 impl<'tcx> Clean<Type> for ty::ProjectionTy<'tcx> {
 386     fn clean(&self, cx: &mut DocContext<'_>) -> Type {
 387         let lifted = self.lift_to_tcx(cx.tcx).unwrap();
 388         let trait_ = lifted.trait_ref(cx.tcx).clean(cx);
 389         let self_type = self.self_ty().clean(cx);
 390         Type::QPath {
 391             name: cx.tcx.associated_item(self.item_def_id).name,
 392             self_def_id: self_type.def_id(&cx.cache),
 393             self_type: box self_type,
 394             trait_,
 395         }
 396     }
 397 }
 398
 399 impl Clean<GenericParamDef> for ty::GenericParamDef {
 400     fn clean(&self, cx: &mut DocContext<'_>) -> GenericParamDef {
 401         let (name, kind) = match self.kind {
 402             ty::GenericParamDefKind::Lifetime => {
 403                 (self.name, GenericParamDefKind::Lifetime { outlives: vec![] })
 404             }
 405             ty::GenericParamDefKind::Type { has_default, synthetic, .. } => {
 406                 let default = if has_default {
 407                     let mut default = cx.tcx.type_of(self.def_id).clean(cx);
 408
 409                     // We need to reassign the `self_def_id`, if there's a parent (which is the
 410                     // `Self` type), so we can properly render `<Self as X>` casts, because the
 411                     // information about which type `Self` is, is only present here, but not in
 412                     // the cleaning process of the type itself. To resolve this and have the
 413                     // `self_def_id` set, we override it here.
 414                     // See https://github.com/rust-lang/rust/issues/85454
 415                     if let QPath { ref mut self_def_id, .. } = default {
 416                         *self_def_id = cx.tcx.parent(self.def_id);
 417                     }
 418
 419                     Some(default)
 420                 } else {
 421                     None
 422                 };
 423                 (
 424                     self.name,
 425                     GenericParamDefKind::Type {
 426                         did: self.def_id,
 427                         bounds: vec![], // These are filled in from the where-clauses.
 428                         default: default.map(Box::new),
 429                         synthetic,
 430                     },
 431                 )
 432             }
 433             ty::GenericParamDefKind::Const { has_default, .. } => (
 434                 self.name,
 435                 GenericParamDefKind::Const {
 436                     did: self.def_id,
 437                     ty: Box::new(cx.tcx.type_of(self.def_id).clean(cx)),
 438                     default: match has_default {
 439                         true => Some(Box::new(cx.tcx.const_param_default(self.def_id).to_string())),
 440                         false => None,
 441                     },
 442                 },
 443             ),
 444         };
 445
 446         GenericParamDef { name, kind }
 447     }
 448 }
 449
 450 impl Clean<GenericParamDef> for hir::GenericParam<'_> {
 451     fn clean(&self, cx: &mut DocContext<'_>) -> GenericParamDef {
 452         let (name, kind) = match self.kind {
 453             hir::GenericParamKind::Lifetime { .. } => {
 454                 let outlives = self
 455                     .bounds
 456                     .iter()
 457                     .map(|bound| match bound {
 458                         hir::GenericBound::Outlives(lt) => lt.clean(cx),
 459                         _ => panic!(),
 460                     })
 461                     .collect();
 462                 (self.name.ident().name, GenericParamDefKind::Lifetime { outlives })
 463             }
 464             hir::GenericParamKind::Type { ref default, synthetic } => (
 465                 self.name.ident().name,
 466                 GenericParamDefKind::Type {
 467                     did: cx.tcx.hir().local_def_id(self.hir_id).to_def_id(),
 468                     bounds: self.bounds.iter().filter_map(|x| x.clean(cx)).collect(),
 469                     default: default.map(|t| t.clean(cx)).map(Box::new),
 470                     synthetic,
 471                 },
 472             ),
 473             hir::GenericParamKind::Const { ref ty, default } => (
 474                 self.name.ident().name,
 475                 GenericParamDefKind::Const {
 476                     did: cx.tcx.hir().local_def_id(self.hir_id).to_def_id(),
 477                     ty: Box::new(ty.clean(cx)),
 478                     default: default.map(|ct| {
 479                         let def_id = cx.tcx.hir().local_def_id(ct.hir_id);
 480                         Box::new(ty::Const::from_anon_const(cx.tcx, def_id).to_string())
 481                     }),
 482                 },
 483             ),
 484         };
 485
 486         GenericParamDef { name, kind }
 487     }
 488 }
 489
 490 impl Clean<Generics> for hir::Generics<'_> {
 491     fn clean(&self, cx: &mut DocContext<'_>) -> Generics {
 492         // Synthetic type-parameters are inserted after normal ones.
 493         // In order for normal parameters to be able to refer to synthetic ones,
 494         // scans them first.
 495         fn is_impl_trait(param: &hir::GenericParam<'_>) -> bool {
 496             match param.kind {
 497                 hir::GenericParamKind::Type { synthetic, .. } => synthetic,
 498                 _ => false,
 499             }
 500         }
 501         /// This can happen for `async fn`, e.g. `async fn f<'_>(&'_ self)`.
 502         ///
 503         /// See [`lifetime_to_generic_param`] in [`rustc_ast_lowering`] for more information.
 504         ///
 505         /// [`lifetime_to_generic_param`]: rustc_ast_lowering::LoweringContext::lifetime_to_generic_param
 506         fn is_elided_lifetime(param: &hir::GenericParam<'_>) -> bool {
 507             matches!(
 508                 param.kind,
 509                 hir::GenericParamKind::Lifetime { kind: hir::LifetimeParamKind::Elided }
 510             )
 511         }
 512
 513         let impl_trait_params = self
 514             .params
 515             .iter()
 516             .filter(|param| is_impl_trait(param))
 517             .map(|param| {
 518                 let param: GenericParamDef = param.clean(cx);
 519                 match param.kind {
 520                     GenericParamDefKind::Lifetime { .. } => unreachable!(),
 521                     GenericParamDefKind::Type { did, ref bounds, .. } => {
 522                         cx.impl_trait_bounds.insert(did.into(), bounds.clone());
 523                     }
 524                     GenericParamDefKind::Const { .. } => unreachable!(),
 525                 }
 526                 param
 527             })
 528             .collect::<Vec<_>>();
 529
 530         let mut params = Vec::with_capacity(self.params.len());
 531         for p in self.params.iter().filter(|p| !is_impl_trait(p) && !is_elided_lifetime(p)) {
 532             let p = p.clean(cx);
 533             params.push(p);
 534         }
 535         params.extend(impl_trait_params);
 536
 537         let mut generics = Generics {
 538             params,
 539             where_predicates: self.where_clause.predicates.iter().map(|x| x.clean(cx)).collect(),
 540         };
 541
 542         // Some duplicates are generated for ?Sized bounds between type params and where
 543         // predicates. The point in here is to move the bounds definitions from type params
 544         // to where predicates when such cases occur.
 545         for where_pred in &mut generics.where_predicates {
 546             match *where_pred {
 547                 WherePredicate::BoundPredicate {
 548                     ty: Generic(ref name), ref mut bounds, ..
 549                 } => {
 550                     if bounds.is_empty() {
 551                         for param in &mut generics.params {
 552                             match param.kind {
 553                                 GenericParamDefKind::Lifetime { .. } => {}
 554                                 GenericParamDefKind::Type { bounds: ref mut ty_bounds, .. } => {
 555                                     if &param.name == name {
 556                                         mem::swap(bounds, ty_bounds);
 557                                         break;
 558                                     }
 559                                 }
 560                                 GenericParamDefKind::Const { .. } => {}
 561                             }
 562                         }
 563                     }
 564                 }
 565                 _ => continue,
 566             }
 567         }
 568         generics
 569     }
 570 }
 571
 572 fn clean_ty_generics(
 573     cx: &mut DocContext<'_>,
 574     gens: &ty::Generics,
 575     preds: ty::GenericPredicates<'_>,
 576 ) -> Generics {
 577     // Don't populate `cx.impl_trait_bounds` before `clean`ning `where` clauses,
 578     // since `Clean for ty::Predicate` would consume them.
 579     let mut impl_trait = BTreeMap::<ImplTraitParam, Vec<GenericBound>>::default();
 580
 581     // Bounds in the type_params and lifetimes fields are repeated in the
 582     // predicates field (see rustc_typeck::collect::ty_generics), so remove
 583     // them.
 584     let stripped_params = gens
 585         .params
 586         .iter()
 587         .filter_map(|param| match param.kind {
 588             ty::GenericParamDefKind::Lifetime => Some(param.clean(cx)),
 589             ty::GenericParamDefKind::Type { synthetic, .. } => {
 590                 if param.name == kw::SelfUpper {
 591                     assert_eq!(param.index, 0);
 592                     return None;
 593                 }
 594                 if synthetic {
 595                     impl_trait.insert(param.index.into(), vec![]);
 596                     return None;
 597                 }
 598                 Some(param.clean(cx))
 599             }
 600             ty::GenericParamDefKind::Const { .. } => Some(param.clean(cx)),
 601         })
 602         .collect::<Vec<GenericParamDef>>();
 603
 604     // param index -> [(DefId of trait, associated type name, type)]
 605     let mut impl_trait_proj = FxHashMap::<u32, Vec<(DefId, Symbol, Ty<'_>)>>::default();
 606
 607     let where_predicates = preds
 608         .predicates
 609         .iter()
 610         .flat_map(|(p, _)| {
 611             let mut projection = None;
 612             let param_idx = (|| {
 613                 let bound_p = p.kind();
 614                 match bound_p.skip_binder() {
 615                     ty::PredicateKind::Trait(pred) => {
 616                         if let ty::Param(param) = pred.self_ty().kind() {
 617                             return Some(param.index);
 618                         }
 619                     }
 620                     ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(ty, _reg)) => {
 621                         if let ty::Param(param) = ty.kind() {
 622                             return Some(param.index);
 623                         }
 624                     }
 625                     ty::PredicateKind::Projection(p) => {
 626                         if let ty::Param(param) = p.projection_ty.self_ty().kind() {
 627                             projection = Some(bound_p.rebind(p));
 628                             return Some(param.index);
 629                         }
 630                     }
 631                     _ => (),
 632                 }
 633
 634                 None
 635             })();
 636
 637             if let Some(param_idx) = param_idx {
 638                 if let Some(b) = impl_trait.get_mut(&param_idx.into()) {
 639                     let p: WherePredicate = p.clean(cx)?;
 640
 641                     b.extend(
 642                         p.get_bounds()
 643                             .into_iter()
 644                             .flatten()
 645                             .cloned()
 646                             .filter(|b| !b.is_sized_bound(cx)),
 647                     );
 648
 649                     let proj = projection
 650                         .map(|p| (p.skip_binder().projection_ty.clean(cx), p.skip_binder().term));
 651                     if let Some(((_, trait_did, name), rhs)) =
 652                         proj.as_ref().and_then(|(lhs, rhs)| Some((lhs.projection()?, rhs)))
 653                     {
 654                         // FIXME(...): Remove this unwrap()
 655                         impl_trait_proj.entry(param_idx).or_default().push((
 656                             trait_did,
 657                             name,
 658                             rhs.ty().unwrap(),
 659                         ));
 660                     }
 661
 662                     return None;
 663                 }
 664             }
 665
 666             Some(p)
 667         })
 668         .collect::<Vec<_>>();
 669
 670     for (param, mut bounds) in impl_trait {
 671         // Move trait bounds to the front.
 672         bounds.sort_by_key(|b| !matches!(b, GenericBound::TraitBound(..)));
 673
 674         if let crate::core::ImplTraitParam::ParamIndex(idx) = param {
 675             if let Some(proj) = impl_trait_proj.remove(&idx) {
 676                 for (trait_did, name, rhs) in proj {
 677                     let rhs = rhs.clean(cx);
 678                     simplify::merge_bounds(cx, &mut bounds, trait_did, name, &Term::Type(rhs));
 679                 }
 680             }
 681         } else {
 682             unreachable!();
 683         }
 684
 685         cx.impl_trait_bounds.insert(param, bounds);
 686     }
 687
 688     // Now that `cx.impl_trait_bounds` is populated, we can process
 689     // remaining predicates which could contain `impl Trait`.
 690     let mut where_predicates =
 691         where_predicates.into_iter().flat_map(|p| p.clean(cx)).collect::<Vec<_>>();
 692
 693     // Type parameters have a Sized bound by default unless removed with
 694     // ?Sized. Scan through the predicates and mark any type parameter with
 695     // a Sized bound, removing the bounds as we find them.
 696     //
 697     // Note that associated types also have a sized bound by default, but we
 698     // don't actually know the set of associated types right here so that's
 699     // handled in cleaning associated types
 700     let mut sized_params = FxHashSet::default();
 701     where_predicates.retain(|pred| match *pred {
 702         WherePredicate::BoundPredicate { ty: Generic(ref g), ref bounds, .. } => {
 703             if bounds.iter().any(|b| b.is_sized_bound(cx)) {
 704                 sized_params.insert(*g);
 705                 false
 706             } else {
 707                 true
 708             }
 709         }
 710         _ => true,
 711     });
 712
 713     // Run through the type parameters again and insert a ?Sized
 714     // unbound for any we didn't find to be Sized.
 715     for tp in &stripped_params {
 716         if matches!(tp.kind, types::GenericParamDefKind::Type { .. })
 717             && !sized_params.contains(&tp.name)
 718         {
 719             where_predicates.push(WherePredicate::BoundPredicate {
 720                 ty: Type::Generic(tp.name),
 721                 bounds: vec![GenericBound::maybe_sized(cx)],
 722                 bound_params: Vec::new(),
 723             })
 724         }
 725     }
 726
 727     // It would be nice to collect all of the bounds on a type and recombine
 728     // them if possible, to avoid e.g., `where T: Foo, T: Bar, T: Sized, T: 'a`
 729     // and instead see `where T: Foo + Bar + Sized + 'a`
 730
 731     Generics {
 732         params: stripped_params,
 733         where_predicates: simplify::where_clauses(cx, where_predicates),
 734     }
 735 }
 736
 737 fn clean_fn_or_proc_macro(
 738     item: &hir::Item<'_>,
 739     sig: &hir::FnSig<'_>,
 740     generics: &hir::Generics<'_>,
 741     body_id: hir::BodyId,
 742     name: &mut Symbol,
 743     cx: &mut DocContext<'_>,
 744 ) -> ItemKind {
 745     let attrs = cx.tcx.hir().attrs(item.hir_id());
 746     let macro_kind = attrs.iter().find_map(|a| {
 747         if a.has_name(sym::proc_macro) {
 748             Some(MacroKind::Bang)
 749         } else if a.has_name(sym::proc_macro_derive) {
 750             Some(MacroKind::Derive)
 751         } else if a.has_name(sym::proc_macro_attribute) {
 752             Some(MacroKind::Attr)
 753         } else {
 754             None
 755         }
 756     });
 757     match macro_kind {
 758         Some(kind) => {
 759             if kind == MacroKind::Derive {
 760                 *name = attrs
 761                     .lists(sym::proc_macro_derive)
 762                     .find_map(|mi| mi.ident())
 763                     .expect("proc-macro derives require a name")
 764                     .name;
 765             }
 766
 767             let mut helpers = Vec::new();
 768             for mi in attrs.lists(sym::proc_macro_derive) {
 769                 if !mi.has_name(sym::attributes) {
 770                     continue;
 771                 }
 772
 773                 if let Some(list) = mi.meta_item_list() {
 774                     for inner_mi in list {
 775                         if let Some(ident) = inner_mi.ident() {
 776                             helpers.push(ident.name);
 777                         }
 778                     }
 779                 }
 780             }
 781             ProcMacroItem(ProcMacro { kind, helpers })
 782         }
 783         None => {
 784             let mut func = clean_function(cx, sig, generics, body_id);
 785             let def_id = item.def_id.to_def_id();
 786             func.header.constness =
 787                 if cx.tcx.is_const_fn(def_id) && is_unstable_const_fn(cx.tcx, def_id).is_none() {
 788                     hir::Constness::Const
 789                 } else {
 790                     hir::Constness::NotConst
 791                 };
 792             clean_fn_decl_legacy_const_generics(&mut func, attrs);
 793             FunctionItem(func)
 794         }
 795     }
 796 }
 797
 798 /// This is needed to make it more "readable" when documenting functions using
 799 /// `rustc_legacy_const_generics`. More information in
 800 /// <https://github.com/rust-lang/rust/issues/83167>.
 801 fn clean_fn_decl_legacy_const_generics(func: &mut Function, attrs: &[ast::Attribute]) {
 802     for meta_item_list in attrs
 803         .iter()
 804         .filter(|a| a.has_name(sym::rustc_legacy_const_generics))
 805         .filter_map(|a| a.meta_item_list())
 806     {
 807         for (pos, literal) in meta_item_list.iter().filter_map(|meta| meta.literal()).enumerate() {
 808             match literal.kind {
 809                 ast::LitKind::Int(a, _) => {
 810                     let gen = func.generics.params.remove(0);
 811                     if let GenericParamDef { name, kind: GenericParamDefKind::Const { ty, .. } } =
 812                         gen
 813                     {
 814                         func.decl
 815                             .inputs
 816                             .values
 817                             .insert(a as _, Argument { name, type_: *ty, is_const: true });
 818                     } else {
 819                         panic!("unexpected non const in position {}", pos);
 820                     }
 821                 }
 822                 _ => panic!("invalid arg index"),
 823             }
 824         }
 825     }
 826 }
 827
 828 fn clean_function(
 829     cx: &mut DocContext<'_>,
 830     sig: &hir::FnSig<'_>,
 831     generics: &hir::Generics<'_>,
 832     body_id: hir::BodyId,
 833 ) -> Function {
 834     let (generics, decl) = enter_impl_trait(cx, |cx| {
 835         // NOTE: generics must be cleaned before args
 836         let generics = generics.clean(cx);
 837         let args = clean_args_from_types_and_body_id(cx, sig.decl.inputs, body_id);
 838         let decl = clean_fn_decl_with_args(cx, sig.decl, args);
 839         (generics, decl)
 840     });
 841     Function { decl, generics, header: sig.header }
 842 }
 843
 844 fn clean_args_from_types_and_names(
 845     cx: &mut DocContext<'_>,
 846     types: &[hir::Ty<'_>],
 847     names: &[Ident],
 848 ) -> Arguments {
 849     Arguments {
 850         values: types
 851             .iter()
 852             .enumerate()
 853             .map(|(i, ty)| {
 854                 let mut name = names.get(i).map_or(kw::Empty, |ident| ident.name);
 855                 if name.is_empty() {
 856                     name = kw::Underscore;
 857                 }
 858                 Argument { name, type_: ty.clean(cx), is_const: false }
 859             })
 860             .collect(),
 861     }
 862 }
 863
 864 fn clean_args_from_types_and_body_id(
 865     cx: &mut DocContext<'_>,
 866     types: &[hir::Ty<'_>],
 867     body_id: hir::BodyId,
 868 ) -> Arguments {
 869     let body = cx.tcx.hir().body(body_id);
 870
 871     Arguments {
 872         values: types
 873             .iter()
 874             .enumerate()
 875             .map(|(i, ty)| Argument {
 876                 name: name_from_pat(body.params[i].pat),
 877                 type_: ty.clean(cx),
 878                 is_const: false,
 879             })
 880             .collect(),
 881     }
 882 }
 883
 884 fn clean_fn_decl_with_args(
 885     cx: &mut DocContext<'_>,
 886     decl: &hir::FnDecl<'_>,
 887     args: Arguments,
 888 ) -> FnDecl {
 889     FnDecl { inputs: args, output: decl.output.clean(cx), c_variadic: decl.c_variadic }
 890 }
 891
 892 fn clean_fn_decl_from_did_and_sig(
 893     cx: &mut DocContext<'_>,
 894     did: DefId,
 895     sig: ty::PolyFnSig<'_>,
 896 ) -> FnDecl {
 897     let mut names = if did.is_local() { &[] } else { cx.tcx.fn_arg_names(did) }.iter();
 898
 899     FnDecl {
 900         output: Return(sig.skip_binder().output().clean(cx)),
 901         c_variadic: sig.skip_binder().c_variadic,
 902         inputs: Arguments {
 903             values: sig
 904                 .skip_binder()
 905                 .inputs()
 906                 .iter()
 907                 .map(|t| Argument {
 908                     type_: t.clean(cx),
 909                     name: names.next().map_or(kw::Empty, |i| i.name),
 910                     is_const: false,
 911                 })
 912                 .collect(),
 913         },
 914     }
 915 }
 916
 917 impl Clean<FnRetTy> for hir::FnRetTy<'_> {
 918     fn clean(&self, cx: &mut DocContext<'_>) -> FnRetTy {
 919         match *self {
 920             Self::Return(ref typ) => Return(typ.clean(cx)),
 921             Self::DefaultReturn(..) => DefaultReturn,
 922         }
 923     }
 924 }
 925
 926 impl Clean<bool> for hir::IsAuto {
 927     fn clean(&self, _: &mut DocContext<'_>) -> bool {
 928         match *self {
 929             hir::IsAuto::Yes => true,
 930             hir::IsAuto::No => false,
 931         }
 932     }
 933 }
 934
 935 impl Clean<Path> for hir::TraitRef<'_> {
 936     fn clean(&self, cx: &mut DocContext<'_>) -> Path {
 937         let path = self.path.clean(cx);
 938         register_res(cx, path.res);
 939         path
 940     }
 941 }
 942
 943 impl Clean<PolyTrait> for hir::PolyTraitRef<'_> {
 944     fn clean(&self, cx: &mut DocContext<'_>) -> PolyTrait {
 945         PolyTrait {
 946             trait_: self.trait_ref.clean(cx),
 947             generic_params: self.bound_generic_params.iter().map(|x| x.clean(cx)).collect(),
 948         }
 949     }
 950 }
 951
 952 impl Clean<Item> for hir::TraitItem<'_> {
 953     fn clean(&self, cx: &mut DocContext<'_>) -> Item {
 954         let local_did = self.def_id.to_def_id();
 955         cx.with_param_env(local_did, |cx| {
 956             let inner = match self.kind {
 957                 hir::TraitItemKind::Const(ref ty, default) => {
 958                     let default =
 959                         default.map(|e| ConstantKind::Local { def_id: local_did, body: e });
 960                     AssocConstItem(ty.clean(cx), default)
 961                 }
 962                 hir::TraitItemKind::Fn(ref sig, hir::TraitFn::Provided(body)) => {
 963                     let mut m = clean_function(cx, sig, &self.generics, body);
 964                     if m.header.constness == hir::Constness::Const
 965                         && is_unstable_const_fn(cx.tcx, local_did).is_some()
 966                     {
 967                         m.header.constness = hir::Constness::NotConst;
 968                     }
 969                     MethodItem(m, None)
 970                 }
 971                 hir::TraitItemKind::Fn(ref sig, hir::TraitFn::Required(names)) => {
 972                     let (generics, decl) = enter_impl_trait(cx, |cx| {
 973                         // NOTE: generics must be cleaned before args
 974                         let generics = self.generics.clean(cx);
 975                         let args = clean_args_from_types_and_names(cx, sig.decl.inputs, names);
 976                         let decl = clean_fn_decl_with_args(cx, sig.decl, args);
 977                         (generics, decl)
 978                     });
 979                     let mut t = Function { header: sig.header, decl, generics };
 980                     if t.header.constness == hir::Constness::Const
 981                         && is_unstable_const_fn(cx.tcx, local_did).is_some()
 982                     {
 983                         t.header.constness = hir::Constness::NotConst;
 984                     }
 985                     TyMethodItem(t)
 986                 }
 987                 hir::TraitItemKind::Type(bounds, ref default) => {
 988                     let bounds = bounds.iter().filter_map(|x| x.clean(cx)).collect();
 989                     let default = default.map(|t| t.clean(cx));
 990                     AssocTypeItem(bounds, default)
 991                 }
 992             };
 993             let what_rustc_thinks =
 994                 Item::from_def_id_and_parts(local_did, Some(self.ident.name), inner, cx);
 995             // Trait items always inherit the trait's visibility -- we don't want to show `pub`.
 996             Item { visibility: Inherited, ..what_rustc_thinks }
 997         })
 998     }
 999 }
1000
1001 impl Clean<Item> for hir::ImplItem<'_> {
1002     fn clean(&self, cx: &mut DocContext<'_>) -> Item {
1003         let local_did = self.def_id.to_def_id();
1004         cx.with_param_env(local_did, |cx| {
1005             let inner = match self.kind {
1006                 hir::ImplItemKind::Const(ref ty, expr) => {
1007                     let default = Some(ConstantKind::Local { def_id: local_did, body: expr });
1008                     AssocConstItem(ty.clean(cx), default)
1009                 }
1010                 hir::ImplItemKind::Fn(ref sig, body) => {
1011                     let mut m = clean_function(cx, sig, &self.generics, body);
1012                     if m.header.constness == hir::Constness::Const
1013                         && is_unstable_const_fn(cx.tcx, local_did).is_some()
1014                     {
1015                         m.header.constness = hir::Constness::NotConst;
1016                     }
1017                     MethodItem(m, Some(self.defaultness))
1018                 }
1019                 hir::ImplItemKind::TyAlias(ref hir_ty) => {
1020                     let type_ = hir_ty.clean(cx);
1021                     let item_type = hir_ty_to_ty(cx.tcx, hir_ty).clean(cx);
1022                     TypedefItem(
1023                         Typedef {
1024                             type_,
1025                             generics: Generics::default(),
1026                             item_type: Some(item_type),
1027                         },
1028                         true,
1029                     )
1030                 }
1031             };
1032
1033             let what_rustc_thinks =
1034                 Item::from_def_id_and_parts(local_did, Some(self.ident.name), inner, cx);
1035             let parent_item = cx.tcx.hir().expect_item(cx.tcx.hir().get_parent_item(self.hir_id()));
1036             if let hir::ItemKind::Impl(impl_) = &parent_item.kind {
1037                 if impl_.of_trait.is_some() {
1038                     // Trait impl items always inherit the impl's visibility --
1039                     // we don't want to show `pub`.
1040                     Item { visibility: Inherited, ..what_rustc_thinks }
1041                 } else {
1042                     what_rustc_thinks
1043                 }
1044             } else {
1045                 panic!("found impl item with non-impl parent {:?}", parent_item);
1046             }
1047         })
1048     }
1049 }
1050
1051 impl Clean<Item> for ty::AssocItem {
1052     fn clean(&self, cx: &mut DocContext<'_>) -> Item {
1053         let tcx = cx.tcx;
1054         let kind = match self.kind {
1055             ty::AssocKind::Const => {
1056                 let ty = tcx.type_of(self.def_id);
1057                 let default = if self.defaultness.has_value() {
1058                     Some(ConstantKind::Extern { def_id: self.def_id })
1059                 } else {
1060                     None
1061                 };
1062                 AssocConstItem(ty.clean(cx), default)
1063             }
1064             ty::AssocKind::Fn => {
1065                 let generics = clean_ty_generics(
1066                     cx,
1067                     tcx.generics_of(self.def_id),
1068                     tcx.explicit_predicates_of(self.def_id),
1069                 );
1070                 let sig = tcx.fn_sig(self.def_id);
1071                 let mut decl = clean_fn_decl_from_did_and_sig(cx, self.def_id, sig);
1072
1073                 if self.fn_has_self_parameter {
1074                     let self_ty = match self.container {
1075                         ty::ImplContainer(def_id) => tcx.type_of(def_id),
1076                         ty::TraitContainer(_) => tcx.types.self_param,
1077                     };
1078                     let self_arg_ty = sig.input(0).skip_binder();
1079                     if self_arg_ty == self_ty {
1080                         decl.inputs.values[0].type_ = Generic(kw::SelfUpper);
1081                     } else if let ty::Ref(_, ty, _) = *self_arg_ty.kind() {
1082                         if ty == self_ty {
1083                             match decl.inputs.values[0].type_ {
1084                                 BorrowedRef { ref mut type_, .. } => {
1085                                     **type_ = Generic(kw::SelfUpper)
1086                                 }
1087                                 _ => unreachable!(),
1088                             }
1089                         }
1090                     }
1091                 }
1092
1093                 let provided = match self.container {
1094                     ty::ImplContainer(_) => true,
1095                     ty::TraitContainer(_) => self.defaultness.has_value(),
1096                 };
1097                 if provided {
1098                     let constness = if tcx.is_const_fn_raw(self.def_id) {
1099                         hir::Constness::Const
1100                     } else {
1101                         hir::Constness::NotConst
1102                     };
1103                     let asyncness = tcx.asyncness(self.def_id);
1104                     let defaultness = match self.container {
1105                         ty::ImplContainer(_) => Some(self.defaultness),
1106                         ty::TraitContainer(_) => None,
1107                     };
1108                     MethodItem(
1109                         Function {
1110                             generics,
1111                             decl,
1112                             header: hir::FnHeader {
1113                                 unsafety: sig.unsafety(),
1114                                 abi: sig.abi(),
1115                                 constness,
1116                                 asyncness,
1117                             },
1118                         },
1119                         defaultness,
1120                     )
1121                 } else {
1122                     TyMethodItem(Function {
1123                         generics,
1124                         decl,
1125                         header: hir::FnHeader {
1126                             unsafety: sig.unsafety(),
1127                             abi: sig.abi(),
1128                             constness: hir::Constness::NotConst,
1129                             asyncness: hir::IsAsync::NotAsync,
1130                         },
1131                     })
1132                 }
1133             }
1134             ty::AssocKind::Type => {
1135                 let my_name = self.name;
1136
1137                 if let ty::TraitContainer(_) = self.container {
1138                     let bounds = tcx.explicit_item_bounds(self.def_id);
1139                     let predicates = ty::GenericPredicates { parent: None, predicates: bounds };
1140                     let generics = clean_ty_generics(cx, tcx.generics_of(self.def_id), predicates);
1141                     let mut bounds = generics
1142                         .where_predicates
1143                         .iter()
1144                         .filter_map(|pred| {
1145                             let (name, self_type, trait_, bounds) = match *pred {
1146                                 WherePredicate::BoundPredicate {
1147                                     ty: QPath { ref name, ref self_type, ref trait_, .. },
1148                                     ref bounds,
1149                                     ..
1150                                 } => (name, self_type, trait_, bounds),
1151                                 _ => return None,
1152                             };
1153                             if *name != my_name {
1154                                 return None;
1155                             }
1156                             if trait_.def_id() != self.container.id() {
1157                                 return None;
1158                             }
1159                             match **self_type {
1160                                 Generic(ref s) if *s == kw::SelfUpper => {}
1161                                 _ => return None,
1162                             }
1163                             Some(bounds)
1164                         })
1165                         .flat_map(|i| i.iter().cloned())
1166                         .collect::<Vec<_>>();
1167                     // Our Sized/?Sized bound didn't get handled when creating the generics
1168                     // because we didn't actually get our whole set of bounds until just now
1169                     // (some of them may have come from the trait). If we do have a sized
1170                     // bound, we remove it, and if we don't then we add the `?Sized` bound
1171                     // at the end.
1172                     match bounds.iter().position(|b| b.is_sized_bound(cx)) {
1173                         Some(i) => {
1174                             bounds.remove(i);
1175                         }
1176                         None => bounds.push(GenericBound::maybe_sized(cx)),
1177                     }
1178
1179                     let ty = if self.defaultness.has_value() {
1180                         Some(tcx.type_of(self.def_id))
1181                     } else {
1182                         None
1183                     };
1184
1185                     AssocTypeItem(bounds, ty.map(|t| t.clean(cx)))
1186                 } else {
1187                     // FIXME: when could this happen? Associated items in inherent impls?
1188                     let type_ = tcx.type_of(self.def_id).clean(cx);
1189                     TypedefItem(
1190                         Typedef {
1191                             type_,
1192                             generics: Generics { params: Vec::new(), where_predicates: Vec::new() },
1193                             item_type: None,
1194                         },
1195                         true,
1196                     )
1197                 }
1198             }
1199         };
1200
1201         Item::from_def_id_and_parts(self.def_id, Some(self.name), kind, cx)
1202     }
1203 }
1204
1205 fn clean_qpath(hir_ty: &hir::Ty<'_>, cx: &mut DocContext<'_>) -> Type {
1206     let hir::Ty { hir_id: _, span, ref kind } = *hir_ty;
1207     let qpath = match kind {
1208         hir::TyKind::Path(qpath) => qpath,
1209         _ => unreachable!(),
1210     };
1211
1212     match qpath {
1213         hir::QPath::Resolved(None, ref path) => {
1214             if let Res::Def(DefKind::TyParam, did) = path.res {
1215                 if let Some(new_ty) = cx.substs.get(&did).and_then(|p| p.as_ty()).cloned() {
1216                     return new_ty;
1217                 }
1218                 if let Some(bounds) = cx.impl_trait_bounds.remove(&did.into()) {
1219                     return ImplTrait(bounds);
1220                 }
1221             }
1222
1223             if let Some(expanded) = maybe_expand_private_type_alias(cx, path) {
1224                 expanded
1225             } else {
1226                 let path = path.clean(cx);
1227                 resolve_type(cx, path)
1228             }
1229         }
1230         hir::QPath::Resolved(Some(ref qself), p) => {
1231             // Try to normalize `<X as Y>::T` to a type
1232             let ty = hir_ty_to_ty(cx.tcx, hir_ty);
1233             if let Some(normalized_value) = normalize(cx, ty) {
1234                 return normalized_value.clean(cx);
1235             }
1236
1237             let trait_segments = &p.segments[..p.segments.len() - 1];
1238             let trait_def = cx.tcx.associated_item(p.res.def_id()).container.id();
1239             let trait_ = self::Path {
1240                 res: Res::Def(DefKind::Trait, trait_def),
1241                 segments: trait_segments.iter().map(|x| x.clean(cx)).collect(),
1242             };
1243             register_res(cx, trait_.res);
1244             Type::QPath {
1245                 name: p.segments.last().expect("segments were empty").ident.name,
1246                 self_def_id: Some(DefId::local(qself.hir_id.owner.local_def_index)),
1247                 self_type: box qself.clean(cx),
1248                 trait_,
1249             }
1250         }
1251         hir::QPath::TypeRelative(ref qself, segment) => {
1252             let ty = hir_ty_to_ty(cx.tcx, hir_ty);
1253             let res = match ty.kind() {
1254                 ty::Projection(proj) => Res::Def(DefKind::Trait, proj.trait_ref(cx.tcx).def_id),
1255                 // Rustdoc handles `ty::Error`s by turning them into `Type::Infer`s.
1256                 ty::Error(_) => return Type::Infer,
1257                 _ => bug!("clean: expected associated type, found `{:?}`", ty),
1258             };
1259             let trait_ = hir::Path { span, res, segments: &[] }.clean(cx);
1260             register_res(cx, trait_.res);
1261             Type::QPath {
1262                 name: segment.ident.name,
1263                 self_def_id: res.opt_def_id(),
1264                 self_type: box qself.clean(cx),
1265                 trait_,
1266             }
1267         }
1268         hir::QPath::LangItem(..) => bug!("clean: requiring documentation of lang item"),
1269     }
1270 }
1271
1272 fn maybe_expand_private_type_alias(cx: &mut DocContext<'_>, path: &hir::Path<'_>) -> Option<Type> {
1273     let Res::Def(DefKind::TyAlias, def_id) = path.res else { return None };
1274     // Substitute private type aliases
1275     let Some(def_id) = def_id.as_local() else { return None };
1276     let alias = if !cx.cache.access_levels.is_exported(def_id.to_def_id()) {
1277         &cx.tcx.hir().expect_item(def_id).kind
1278     } else {
1279         return None;
1280     };
1281     let hir::ItemKind::TyAlias(ty, generics) = alias else { return None };
1282
1283     let provided_params = &path.segments.last().expect("segments were empty");
1284     let mut substs = FxHashMap::default();
1285     let generic_args = provided_params.args();
1286
1287     let mut indices: hir::GenericParamCount = Default::default();
1288     for param in generics.params.iter() {
1289         match param.kind {
1290             hir::GenericParamKind::Lifetime { .. } => {
1291                 let mut j = 0;
1292                 let lifetime = generic_args.args.iter().find_map(|arg| match arg {
1293                     hir::GenericArg::Lifetime(lt) => {
1294                         if indices.lifetimes == j {
1295                             return Some(lt);
1296                         }
1297                         j += 1;
1298                         None
1299                     }
1300                     _ => None,
1301                 });
1302                 if let Some(lt) = lifetime.cloned() {
1303                     let lt_def_id = cx.tcx.hir().local_def_id(param.hir_id);
1304                     let cleaned = if !lt.is_elided() {
1305                         lt.clean(cx)
1306                     } else {
1307                         self::types::Lifetime::elided()
1308                     };
1309                     substs.insert(lt_def_id.to_def_id(), SubstParam::Lifetime(cleaned));
1310                 }
1311                 indices.lifetimes += 1;
1312             }
1313             hir::GenericParamKind::Type { ref default, .. } => {
1314                 let ty_param_def_id = cx.tcx.hir().local_def_id(param.hir_id);
1315                 let mut j = 0;
1316                 let type_ = generic_args.args.iter().find_map(|arg| match arg {
1317                     hir::GenericArg::Type(ty) => {
1318                         if indices.types == j {
1319                             return Some(ty);
1320                         }
1321                         j += 1;
1322                         None
1323                     }
1324                     _ => None,
1325                 });
1326                 if let Some(ty) = type_ {
1327                     substs.insert(ty_param_def_id.to_def_id(), SubstParam::Type(ty.clean(cx)));
1328                 } else if let Some(default) = *default {
1329                     substs.insert(ty_param_def_id.to_def_id(), SubstParam::Type(default.clean(cx)));
1330                 }
1331                 indices.types += 1;
1332             }
1333             hir::GenericParamKind::Const { .. } => {
1334                 let const_param_def_id = cx.tcx.hir().local_def_id(param.hir_id);
1335                 let mut j = 0;
1336                 let const_ = generic_args.args.iter().find_map(|arg| match arg {
1337                     hir::GenericArg::Const(ct) => {
1338                         if indices.consts == j {
1339                             return Some(ct);
1340                         }
1341                         j += 1;
1342                         None
1343                     }
1344                     _ => None,
1345                 });
1346                 if let Some(ct) = const_ {
1347                     substs
1348                         .insert(const_param_def_id.to_def_id(), SubstParam::Constant(ct.clean(cx)));
1349                 }
1350                 // FIXME(const_generics_defaults)
1351                 indices.consts += 1;
1352             }
1353         }
1354     }
1355
1356     Some(cx.enter_alias(substs, |cx| ty.clean(cx)))
1357 }
1358
1359 impl Clean<Type> for hir::Ty<'_> {
1360     fn clean(&self, cx: &mut DocContext<'_>) -> Type {
1361         use rustc_hir::*;
1362
1363         match self.kind {
1364             TyKind::Never => Primitive(PrimitiveType::Never),
1365             TyKind::Ptr(ref m) => RawPointer(m.mutbl, box m.ty.clean(cx)),
1366             TyKind::Rptr(ref l, ref m) => {
1367                 // There are two times a `Fresh` lifetime can be created:
1368                 // 1. For `&'_ x`, written by the user. This corresponds to `lower_lifetime` in `rustc_ast_lowering`.
1369                 // 2. For `&x` as a parameter to an `async fn`. This corresponds to `elided_ref_lifetime in `rustc_ast_lowering`.
1370                 //    See #59286 for more information.
1371                 // Ideally we would only hide the `'_` for case 2., but I don't know a way to distinguish it.
1372                 // Turning `fn f(&'_ self)` into `fn f(&self)` isn't the worst thing in the world, though;
1373                 // there's no case where it could cause the function to fail to compile.
1374                 let elided =
1375                     l.is_elided() || matches!(l.name, LifetimeName::Param(ParamName::Fresh(_)));
1376                 let lifetime = if elided { None } else { Some(l.clean(cx)) };
1377                 BorrowedRef { lifetime, mutability: m.mutbl, type_: box m.ty.clean(cx) }
1378             }
1379             TyKind::Slice(ref ty) => Slice(box ty.clean(cx)),
1380             TyKind::Array(ref ty, ref length) => {
1381                 let length = match length {
1382                     hir::ArrayLen::Infer(_, _) => "_".to_string(),
1383                     hir::ArrayLen::Body(anon_const) => {
1384                         let def_id = cx.tcx.hir().local_def_id(anon_const.hir_id);
1385                         // NOTE(min_const_generics): We can't use `const_eval_poly` for constants
1386                         // as we currently do not supply the parent generics to anonymous constants
1387                         // but do allow `ConstKind::Param`.
1388                         //
1389                         // `const_eval_poly` tries to to first substitute generic parameters which
1390                         // results in an ICE while manually constructing the constant and using `eval`
1391                         // does nothing for `ConstKind::Param`.
1392                         let ct = ty::Const::from_anon_const(cx.tcx, def_id);
1393                         let param_env = cx.tcx.param_env(def_id);
1394                         print_const(cx, ct.eval(cx.tcx, param_env))
1395                     }
1396                 };
1397
1398                 Array(box ty.clean(cx), length)
1399             }
1400             TyKind::Tup(tys) => Tuple(tys.iter().map(|x| x.clean(cx)).collect()),
1401             TyKind::OpaqueDef(item_id, _) => {
1402                 let item = cx.tcx.hir().item(item_id);
1403                 if let hir::ItemKind::OpaqueTy(ref ty) = item.kind {
1404                     ImplTrait(ty.bounds.iter().filter_map(|x| x.clean(cx)).collect())
1405                 } else {
1406                     unreachable!()
1407                 }
1408             }
1409             TyKind::Path(_) => clean_qpath(self, cx),
1410             TyKind::TraitObject(bounds, ref lifetime, _) => {
1411                 let bounds = bounds.iter().map(|bound| bound.clean(cx)).collect();
1412                 let lifetime = if !lifetime.is_elided() { Some(lifetime.clean(cx)) } else { None };
1413                 DynTrait(bounds, lifetime)
1414             }
1415             TyKind::BareFn(ref barefn) => BareFunction(box barefn.clean(cx)),
1416             // Rustdoc handles `TyKind::Err`s by turning them into `Type::Infer`s.
1417             TyKind::Infer | TyKind::Err => Infer,
1418             TyKind::Typeof(..) => panic!("unimplemented type {:?}", self.kind),
1419         }
1420     }
1421 }
1422
1423 /// Returns `None` if the type could not be normalized
1424 fn normalize<'tcx>(cx: &mut DocContext<'tcx>, ty: Ty<'_>) -> Option<Ty<'tcx>> {
1425     // HACK: low-churn fix for #79459 while we wait for a trait normalization fix
1426     if !cx.tcx.sess.opts.debugging_opts.normalize_docs {
1427         return None;
1428     }
1429
1430     use crate::rustc_trait_selection::infer::TyCtxtInferExt;
1431     use crate::rustc_trait_selection::traits::query::normalize::AtExt;
1432     use rustc_middle::traits::ObligationCause;
1433
1434     // Try to normalize `<X as Y>::T` to a type
1435     let lifted = ty.lift_to_tcx(cx.tcx).unwrap();
1436     let normalized = cx.tcx.infer_ctxt().enter(|infcx| {
1437         infcx
1438             .at(&ObligationCause::dummy(), cx.param_env)
1439             .normalize(lifted)
1440             .map(|resolved| infcx.resolve_vars_if_possible(resolved.value))
1441     });
1442     match normalized {
1443         Ok(normalized_value) => {
1444             debug!("normalized {:?} to {:?}", ty, normalized_value);
1445             Some(normalized_value)
1446         }
1447         Err(err) => {
1448             debug!("failed to normalize {:?}: {:?}", ty, err);
1449             None
1450         }
1451     }
1452 }
1453
1454 impl<'tcx> Clean<Type> for Ty<'tcx> {
1455     fn clean(&self, cx: &mut DocContext<'_>) -> Type {
1456         trace!("cleaning type: {:?}", self);
1457         let ty = normalize(cx, self).unwrap_or(self);
1458         match *ty.kind() {
1459             ty::Never => Primitive(PrimitiveType::Never),
1460             ty::Bool => Primitive(PrimitiveType::Bool),
1461             ty::Char => Primitive(PrimitiveType::Char),
1462             ty::Int(int_ty) => Primitive(int_ty.into()),
1463             ty::Uint(uint_ty) => Primitive(uint_ty.into()),
1464             ty::Float(float_ty) => Primitive(float_ty.into()),
1465             ty::Str => Primitive(PrimitiveType::Str),
1466             ty::Slice(ty) => Slice(box ty.clean(cx)),
1467             ty::Array(ty, n) => {
1468                 let mut n = cx.tcx.lift(n).expect("array lift failed");
1469                 n = n.eval(cx.tcx, ty::ParamEnv::reveal_all());
1470                 let n = print_const(cx, n);
1471                 Array(box ty.clean(cx), n)
1472             }
1473             ty::RawPtr(mt) => RawPointer(mt.mutbl, box mt.ty.clean(cx)),
1474             ty::Ref(r, ty, mutbl) => {
1475                 BorrowedRef { lifetime: r.clean(cx), mutability: mutbl, type_: box ty.clean(cx) }
1476             }
1477             ty::FnDef(..) | ty::FnPtr(_) => {
1478                 let ty = cx.tcx.lift(*self).expect("FnPtr lift failed");
1479                 let sig = ty.fn_sig(cx.tcx);
1480                 let def_id = DefId::local(CRATE_DEF_INDEX);
1481                 let decl = clean_fn_decl_from_did_and_sig(cx, def_id, sig);
1482                 BareFunction(box BareFunctionDecl {
1483                     unsafety: sig.unsafety(),
1484                     generic_params: Vec::new(),
1485                     decl,
1486                     abi: sig.abi(),
1487                 })
1488             }
1489             ty::Adt(def, substs) => {
1490                 let did = def.did;
1491                 let kind = match def.adt_kind() {
1492                     AdtKind::Struct => ItemType::Struct,
1493                     AdtKind::Union => ItemType::Union,
1494                     AdtKind::Enum => ItemType::Enum,
1495                 };
1496                 inline::record_extern_fqn(cx, did, kind);
1497                 let path = external_path(cx, did, false, vec![], substs);
1498                 Type::Path { path }
1499             }
1500             ty::Foreign(did) => {
1501                 inline::record_extern_fqn(cx, did, ItemType::ForeignType);
1502                 let path = external_path(cx, did, false, vec![], InternalSubsts::empty());
1503                 Type::Path { path }
1504             }
1505             ty::Dynamic(obj, ref reg) => {
1506                 // HACK: pick the first `did` as the `did` of the trait object. Someone
1507                 // might want to implement "native" support for marker-trait-only
1508                 // trait objects.
1509                 let mut dids = obj.principal_def_id().into_iter().chain(obj.auto_traits());
1510                 let did = dids
1511                     .next()
1512                     .unwrap_or_else(|| panic!("found trait object `{:?}` with no traits?", self));
1513                 let substs = match obj.principal() {
1514                     Some(principal) => principal.skip_binder().substs,
1515                     // marker traits have no substs.
1516                     _ => cx.tcx.intern_substs(&[]),
1517                 };
1518
1519                 inline::record_extern_fqn(cx, did, ItemType::Trait);
1520
1521                 let lifetime = reg.clean(cx);
1522                 let mut bounds = vec![];
1523
1524                 for did in dids {
1525                     let empty = cx.tcx.intern_substs(&[]);
1526                     let path = external_path(cx, did, false, vec![], empty);
1527                     inline::record_extern_fqn(cx, did, ItemType::Trait);
1528                     let bound = PolyTrait { trait_: path, generic_params: Vec::new() };
1529                     bounds.push(bound);
1530                 }
1531
1532                 let mut bindings = vec![];
1533                 for pb in obj.projection_bounds() {
1534                     bindings.push(TypeBinding {
1535                         name: cx.tcx.associated_item(pb.item_def_id()).name,
1536                         kind: TypeBindingKind::Equality { term: pb.skip_binder().term.clean(cx) },
1537                     });
1538                 }
1539
1540                 let path = external_path(cx, did, false, bindings, substs);
1541                 bounds.insert(0, PolyTrait { trait_: path, generic_params: Vec::new() });
1542
1543                 DynTrait(bounds, lifetime)
1544             }
1545             ty::Tuple(t) => Tuple(t.iter().map(|t| t.expect_ty().clean(cx)).collect()),
1546
1547             ty::Projection(ref data) => data.clean(cx),
1548
1549             ty::Param(ref p) => {
1550                 if let Some(bounds) = cx.impl_trait_bounds.remove(&p.index.into()) {
1551                     ImplTrait(bounds)
1552                 } else {
1553                     Generic(p.name)
1554                 }
1555             }
1556
1557             ty::Opaque(def_id, substs) => {
1558                 // Grab the "TraitA + TraitB" from `impl TraitA + TraitB`,
1559                 // by looking up the bounds associated with the def_id.
1560                 let substs = cx.tcx.lift(substs).expect("Opaque lift failed");
1561                 let bounds = cx
1562                     .tcx
1563                     .explicit_item_bounds(def_id)
1564                     .iter()
1565                     .map(|(bound, _)| bound.subst(cx.tcx, substs))
1566                     .collect::<Vec<_>>();
1567                 let mut regions = vec![];
1568                 let mut has_sized = false;
1569                 let mut bounds = bounds
1570                     .iter()
1571                     .filter_map(|bound| {
1572                         let bound_predicate = bound.kind();
1573                         let trait_ref = match bound_predicate.skip_binder() {
1574                             ty::PredicateKind::Trait(tr) => bound_predicate.rebind(tr.trait_ref),
1575                             ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(_ty, reg)) => {
1576                                 if let Some(r) = reg.clean(cx) {
1577                                     regions.push(GenericBound::Outlives(r));
1578                                 }
1579                                 return None;
1580                             }
1581                             _ => return None,
1582                         };
1583
1584                         if let Some(sized) = cx.tcx.lang_items().sized_trait() {
1585                             if trait_ref.def_id() == sized {
1586                                 has_sized = true;
1587                                 return None;
1588                             }
1589                         }
1590
1591                         let bindings: Vec<_> = bounds
1592                             .iter()
1593                             .filter_map(|bound| {
1594                                 if let ty::PredicateKind::Projection(proj) =
1595                                     bound.kind().skip_binder()
1596                                 {
1597                                     if proj.projection_ty.trait_ref(cx.tcx)
1598                                         == trait_ref.skip_binder()
1599                                     {
1600                                         Some(TypeBinding {
1601                                             name: cx
1602                                                 .tcx
1603                                                 .associated_item(proj.projection_ty.item_def_id)
1604                                                 .name,
1605                                             kind: TypeBindingKind::Equality {
1606                                                 term: proj.term.clean(cx),
1607                                             },
1608                                         })
1609                                     } else {
1610                                         None
1611                                     }
1612                                 } else {
1613                                     None
1614                                 }
1615                             })
1616                             .collect();
1617
1618                         Some(clean_poly_trait_ref_with_bindings(cx, trait_ref, &bindings))
1619                     })
1620                     .collect::<Vec<_>>();
1621                 bounds.extend(regions);
1622                 if !has_sized && !bounds.is_empty() {
1623                     bounds.insert(0, GenericBound::maybe_sized(cx));
1624                 }
1625                 ImplTrait(bounds)
1626             }
1627
1628             ty::Closure(..) | ty::Generator(..) => Tuple(vec![]), // FIXME(pcwalton)
1629
1630             ty::Bound(..) => panic!("Bound"),
1631             ty::Placeholder(..) => panic!("Placeholder"),
1632             ty::GeneratorWitness(..) => panic!("GeneratorWitness"),
1633             ty::Infer(..) => panic!("Infer"),
1634             ty::Error(_) => panic!("Error"),
1635         }
1636     }
1637 }
1638
1639 impl<'tcx> Clean<Constant> for ty::Const<'tcx> {
1640     fn clean(&self, cx: &mut DocContext<'_>) -> Constant {
1641         // FIXME: instead of storing the stringified expression, store `self` directly instead.
1642         Constant {
1643             type_: self.ty.clean(cx),
1644             kind: ConstantKind::TyConst { expr: self.to_string() },
1645         }
1646     }
1647 }
1648
1649 impl Clean<Item> for hir::FieldDef<'_> {
1650     fn clean(&self, cx: &mut DocContext<'_>) -> Item {
1651         let def_id = cx.tcx.hir().local_def_id(self.hir_id).to_def_id();
1652         clean_field(def_id, self.ident.name, self.ty.clean(cx), cx)
1653     }
1654 }
1655
1656 impl Clean<Item> for ty::FieldDef {
1657     fn clean(&self, cx: &mut DocContext<'_>) -> Item {
1658         clean_field(self.did, self.name, cx.tcx.type_of(self.did).clean(cx), cx)
1659     }
1660 }
1661
1662 fn clean_field(def_id: DefId, name: Symbol, ty: Type, cx: &mut DocContext<'_>) -> Item {
1663     let what_rustc_thinks =
1664         Item::from_def_id_and_parts(def_id, Some(name), StructFieldItem(ty), cx);
1665     if is_field_vis_inherited(cx.tcx, def_id) {
1666         // Variant fields inherit their enum's visibility.
1667         Item { visibility: Visibility::Inherited, ..what_rustc_thinks }
1668     } else {
1669         what_rustc_thinks
1670     }
1671 }
1672
1673 fn is_field_vis_inherited(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
1674     let parent = tcx
1675         .parent(def_id)
1676         .expect("is_field_vis_inherited can only be called on struct or variant fields");
1677     match tcx.def_kind(parent) {
1678         DefKind::Struct | DefKind::Union => false,
1679         DefKind::Variant => true,
1680         // FIXME: what about DefKind::Ctor?
1681         parent_kind => panic!("unexpected parent kind: {:?}", parent_kind),
1682     }
1683 }
1684
1685 impl Clean<Visibility> for ty::Visibility {
1686     fn clean(&self, _cx: &mut DocContext<'_>) -> Visibility {
1687         match *self {
1688             ty::Visibility::Public => Visibility::Public,
1689             // NOTE: this is not quite right: `ty` uses `Invisible` to mean 'private',
1690             // while rustdoc really does mean inherited. That means that for enum variants, such as
1691             // `pub enum E { V }`, `V` will be marked as `Public` by `ty`, but as `Inherited` by rustdoc.
1692             // Various parts of clean override `tcx.visibility` explicitly to make sure this distinction is captured.
1693             ty::Visibility::Invisible => Visibility::Inherited,
1694             ty::Visibility::Restricted(module) => Visibility::Restricted(module),
1695         }
1696     }
1697 }
1698
1699 impl Clean<VariantStruct> for rustc_hir::VariantData<'_> {
1700     fn clean(&self, cx: &mut DocContext<'_>) -> VariantStruct {
1701         VariantStruct {
1702             struct_type: CtorKind::from_hir(self),
1703             fields: self.fields().iter().map(|x| x.clean(cx)).collect(),
1704             fields_stripped: false,
1705         }
1706     }
1707 }
1708
1709 impl Clean<Vec<Item>> for hir::VariantData<'_> {
1710     fn clean(&self, cx: &mut DocContext<'_>) -> Vec<Item> {
1711         self.fields().iter().map(|x| x.clean(cx)).collect()
1712     }
1713 }
1714
1715 impl Clean<Item> for ty::VariantDef {
1716     fn clean(&self, cx: &mut DocContext<'_>) -> Item {
1717         let kind = match self.ctor_kind {
1718             CtorKind::Const => Variant::CLike,
1719             CtorKind::Fn => {
1720                 Variant::Tuple(self.fields.iter().map(|field| field.clean(cx)).collect())
1721             }
1722             CtorKind::Fictive => Variant::Struct(VariantStruct {
1723                 struct_type: CtorKind::Fictive,
1724                 fields_stripped: false,
1725                 fields: self.fields.iter().map(|field| field.clean(cx)).collect(),
1726             }),
1727         };
1728         let what_rustc_thinks =
1729             Item::from_def_id_and_parts(self.def_id, Some(self.name), VariantItem(kind), cx);
1730         // don't show `pub` for variants, which always inherit visibility
1731         Item { visibility: Inherited, ..what_rustc_thinks }
1732     }
1733 }
1734
1735 impl Clean<Variant> for hir::VariantData<'_> {
1736     fn clean(&self, cx: &mut DocContext<'_>) -> Variant {
1737         match self {
1738             hir::VariantData::Struct(..) => Variant::Struct(self.clean(cx)),
1739             hir::VariantData::Tuple(..) => Variant::Tuple(self.clean(cx)),
1740             hir::VariantData::Unit(..) => Variant::CLike,
1741         }
1742     }
1743 }
1744
1745 impl Clean<Path> for hir::Path<'_> {
1746     fn clean(&self, cx: &mut DocContext<'_>) -> Path {
1747         Path { res: self.res, segments: self.segments.iter().map(|x| x.clean(cx)).collect() }
1748     }
1749 }
1750
1751 impl Clean<GenericArgs> for hir::GenericArgs<'_> {
1752     fn clean(&self, cx: &mut DocContext<'_>) -> GenericArgs {
1753         if self.parenthesized {
1754             let output = self.bindings[0].ty().clean(cx);
1755             let output =
1756                 if output != Type::Tuple(Vec::new()) { Some(Box::new(output)) } else { None };
1757             let inputs = self.inputs().iter().map(|x| x.clean(cx)).collect();
1758             GenericArgs::Parenthesized { inputs, output }
1759         } else {
1760             let args = self
1761                 .args
1762                 .iter()
1763                 .map(|arg| match arg {
1764                     hir::GenericArg::Lifetime(lt) if !lt.is_elided() => {
1765                         GenericArg::Lifetime(lt.clean(cx))
1766                     }
1767                     hir::GenericArg::Lifetime(_) => GenericArg::Lifetime(Lifetime::elided()),
1768                     hir::GenericArg::Type(ty) => GenericArg::Type(ty.clean(cx)),
1769                     hir::GenericArg::Const(ct) => GenericArg::Const(Box::new(ct.clean(cx))),
1770                     hir::GenericArg::Infer(_inf) => GenericArg::Infer,
1771                 })
1772                 .collect();
1773             let bindings = self.bindings.iter().map(|x| x.clean(cx)).collect();
1774             GenericArgs::AngleBracketed { args, bindings }
1775         }
1776     }
1777 }
1778
1779 impl Clean<PathSegment> for hir::PathSegment<'_> {
1780     fn clean(&self, cx: &mut DocContext<'_>) -> PathSegment {
1781         PathSegment { name: self.ident.name, args: self.args().clean(cx) }
1782     }
1783 }
1784
1785 impl Clean<BareFunctionDecl> for hir::BareFnTy<'_> {
1786     fn clean(&self, cx: &mut DocContext<'_>) -> BareFunctionDecl {
1787         let (generic_params, decl) = enter_impl_trait(cx, |cx| {
1788             // NOTE: generics must be cleaned before args
1789             let generic_params = self.generic_params.iter().map(|x| x.clean(cx)).collect();
1790             let args = clean_args_from_types_and_names(cx, self.decl.inputs, self.param_names);
1791             let decl = clean_fn_decl_with_args(cx, self.decl, args);
1792             (generic_params, decl)
1793         });
1794         BareFunctionDecl { unsafety: self.unsafety, abi: self.abi, decl, generic_params }
1795     }
1796 }
1797
1798 fn clean_maybe_renamed_item(
1799     cx: &mut DocContext<'_>,
1800     item: &hir::Item<'_>,
1801     renamed: Option<Symbol>,
1802 ) -> Vec<Item> {
1803     use hir::ItemKind;
1804
1805     let def_id = item.def_id.to_def_id();
1806     let mut name = renamed.unwrap_or_else(|| cx.tcx.hir().name(item.hir_id()));
1807     cx.with_param_env(def_id, |cx| {
1808         let kind = match item.kind {
1809             ItemKind::Static(ty, mutability, body_id) => {
1810                 StaticItem(Static { type_: ty.clean(cx), mutability, expr: Some(body_id) })
1811             }
1812             ItemKind::Const(ty, body_id) => ConstantItem(Constant {
1813                 type_: ty.clean(cx),
1814                 kind: ConstantKind::Local { body: body_id, def_id },
1815             }),
1816             ItemKind::OpaqueTy(ref ty) => OpaqueTyItem(OpaqueTy {
1817                 bounds: ty.bounds.iter().filter_map(|x| x.clean(cx)).collect(),
1818                 generics: ty.generics.clean(cx),
1819             }),
1820             ItemKind::TyAlias(hir_ty, ref generics) => {
1821                 let rustdoc_ty = hir_ty.clean(cx);
1822                 let ty = hir_ty_to_ty(cx.tcx, hir_ty).clean(cx);
1823                 TypedefItem(
1824                     Typedef {
1825                         type_: rustdoc_ty,
1826                         generics: generics.clean(cx),
1827                         item_type: Some(ty),
1828                     },
1829                     false,
1830                 )
1831             }
1832             ItemKind::Enum(ref def, ref generics) => EnumItem(Enum {
1833                 variants: def.variants.iter().map(|v| v.clean(cx)).collect(),
1834                 generics: generics.clean(cx),
1835                 variants_stripped: false,
1836             }),
1837             ItemKind::TraitAlias(ref generics, bounds) => TraitAliasItem(TraitAlias {
1838                 generics: generics.clean(cx),
1839                 bounds: bounds.iter().filter_map(|x| x.clean(cx)).collect(),
1840             }),
1841             ItemKind::Union(ref variant_data, ref generics) => UnionItem(Union {
1842                 generics: generics.clean(cx),
1843                 fields: variant_data.fields().iter().map(|x| x.clean(cx)).collect(),
1844                 fields_stripped: false,
1845             }),
1846             ItemKind::Struct(ref variant_data, ref generics) => StructItem(Struct {
1847                 struct_type: CtorKind::from_hir(variant_data),
1848                 generics: generics.clean(cx),
1849                 fields: variant_data.fields().iter().map(|x| x.clean(cx)).collect(),
1850                 fields_stripped: false,
1851             }),
1852             ItemKind::Impl(ref impl_) => return clean_impl(impl_, item.hir_id(), cx),
1853             // proc macros can have a name set by attributes
1854             ItemKind::Fn(ref sig, ref generics, body_id) => {
1855                 clean_fn_or_proc_macro(item, sig, generics, body_id, &mut name, cx)
1856             }
1857             ItemKind::Macro(ref macro_def) => {
1858                 let ty_vis = cx.tcx.visibility(def_id).clean(cx);
1859                 MacroItem(Macro {
1860                     source: display_macro_source(cx, name, macro_def, def_id, ty_vis),
1861                 })
1862             }
1863             ItemKind::Trait(is_auto, unsafety, ref generics, bounds, item_ids) => {
1864                 let items =
1865                     item_ids.iter().map(|ti| cx.tcx.hir().trait_item(ti.id).clean(cx)).collect();
1866                 TraitItem(Trait {
1867                     unsafety,
1868                     items,
1869                     generics: generics.clean(cx),
1870                     bounds: bounds.iter().filter_map(|x| x.clean(cx)).collect(),
1871                     is_auto: is_auto.clean(cx),
1872                 })
1873             }
1874             ItemKind::ExternCrate(orig_name) => {
1875                 return clean_extern_crate(item, name, orig_name, cx);
1876             }
1877             ItemKind::Use(path, kind) => {
1878                 return clean_use_statement(item, name, path, kind, cx);
1879             }
1880             _ => unreachable!("not yet converted"),
1881         };
1882
1883         vec![Item::from_def_id_and_parts(def_id, Some(name), kind, cx)]
1884     })
1885 }
1886
1887 impl Clean<Item> for hir::Variant<'_> {
1888     fn clean(&self, cx: &mut DocContext<'_>) -> Item {
1889         let kind = VariantItem(self.data.clean(cx));
1890         let what_rustc_thinks =
1891             Item::from_hir_id_and_parts(self.id, Some(self.ident.name), kind, cx);
1892         // don't show `pub` for variants, which are always public
1893         Item { visibility: Inherited, ..what_rustc_thinks }
1894     }
1895 }
1896
1897 fn clean_impl(impl_: &hir::Impl<'_>, hir_id: hir::HirId, cx: &mut DocContext<'_>) -> Vec<Item> {
1898     let tcx = cx.tcx;
1899     let mut ret = Vec::new();
1900     let trait_ = impl_.of_trait.as_ref().map(|t| t.clean(cx));
1901     let items =
1902         impl_.items.iter().map(|ii| tcx.hir().impl_item(ii.id).clean(cx)).collect::<Vec<_>>();
1903     let def_id = tcx.hir().local_def_id(hir_id);
1904
1905     // If this impl block is an implementation of the Deref trait, then we
1906     // need to try inlining the target's inherent impl blocks as well.
1907     if trait_.as_ref().map(|t| t.def_id()) == tcx.lang_items().deref_trait() {
1908         build_deref_target_impls(cx, &items, &mut ret);
1909     }
1910
1911     let for_ = impl_.self_ty.clean(cx);
1912     let type_alias = for_.def_id(&cx.cache).and_then(|did| match tcx.def_kind(did) {
1913         DefKind::TyAlias => Some(tcx.type_of(did).clean(cx)),
1914         _ => None,
1915     });
1916     let mut make_item = |trait_: Option<Path>, for_: Type, items: Vec<Item>| {
1917         let kind = ImplItem(Impl {
1918             unsafety: impl_.unsafety,
1919             generics: impl_.generics.clean(cx),
1920             trait_,
1921             for_,
1922             items,
1923             polarity: tcx.impl_polarity(def_id),
1924             kind: ImplKind::Normal,
1925         });
1926         Item::from_hir_id_and_parts(hir_id, None, kind, cx)
1927     };
1928     if let Some(type_alias) = type_alias {
1929         ret.push(make_item(trait_.clone(), type_alias, items.clone()));
1930     }
1931     ret.push(make_item(trait_, for_, items));
1932     ret
1933 }
1934
1935 fn clean_extern_crate(
1936     krate: &hir::Item<'_>,
1937     name: Symbol,
1938     orig_name: Option<Symbol>,
1939     cx: &mut DocContext<'_>,
1940 ) -> Vec<Item> {
1941     // this is the ID of the `extern crate` statement
1942     let cnum = cx.tcx.extern_mod_stmt_cnum(krate.def_id).unwrap_or(LOCAL_CRATE);
1943     // this is the ID of the crate itself
1944     let crate_def_id = DefId { krate: cnum, index: CRATE_DEF_INDEX };
1945     let attrs = cx.tcx.hir().attrs(krate.hir_id());
1946     let ty_vis = cx.tcx.visibility(krate.def_id);
1947     let please_inline = ty_vis.is_public()
1948         && attrs.iter().any(|a| {
1949             a.has_name(sym::doc)
1950                 && match a.meta_item_list() {
1951                     Some(l) => attr::list_contains_name(&l, sym::inline),
1952                     None => false,
1953                 }
1954         });
1955
1956     if please_inline {
1957         let mut visited = FxHashSet::default();
1958
1959         let res = Res::Def(DefKind::Mod, crate_def_id);
1960
1961         if let Some(items) = inline::try_inline(
1962             cx,
1963             cx.tcx.parent_module(krate.hir_id()).to_def_id(),
1964             Some(krate.def_id.to_def_id()),
1965             res,
1966             name,
1967             Some(attrs),
1968             &mut visited,
1969         ) {
1970             return items;
1971         }
1972     }
1973
1974     // FIXME: using `from_def_id_and_kind` breaks `rustdoc/masked` for some reason
1975     vec![Item {
1976         name: Some(name),
1977         attrs: box attrs.clean(cx),
1978         def_id: crate_def_id.into(),
1979         visibility: ty_vis.clean(cx),
1980         kind: box ExternCrateItem { src: orig_name },
1981         cfg: attrs.cfg(cx.tcx, &cx.cache.hidden_cfg),
1982     }]
1983 }
1984
1985 fn clean_use_statement(
1986     import: &hir::Item<'_>,
1987     name: Symbol,
1988     path: &hir::Path<'_>,
1989     kind: hir::UseKind,
1990     cx: &mut DocContext<'_>,
1991 ) -> Vec<Item> {
1992     // We need this comparison because some imports (for std types for example)
1993     // are "inserted" as well but directly by the compiler and they should not be
1994     // taken into account.
1995     if import.span.ctxt().outer_expn_data().kind == ExpnKind::AstPass(AstPass::StdImports) {
1996         return Vec::new();
1997     }
1998
1999     let visibility = cx.tcx.visibility(import.def_id);
2000     let attrs = cx.tcx.hir().attrs(import.hir_id());
2001     let inline_attr = attrs.lists(sym::doc).get_word_attr(sym::inline);
2002     let pub_underscore = visibility.is_public() && name == kw::Underscore;
2003     let current_mod = cx.tcx.parent_module_from_def_id(import.def_id);
2004
2005     // The parent of the module in which this import resides. This
2006     // is the same as `current_mod` if that's already the top
2007     // level module.
2008     let parent_mod = cx.tcx.parent_module_from_def_id(current_mod);
2009
2010     // This checks if the import can be seen from a higher level module.
2011     // In other words, it checks if the visibility is the equivalent of
2012     // `pub(super)` or higher. If the current module is the top level
2013     // module, there isn't really a parent module, which makes the results
2014     // meaningless. In this case, we make sure the answer is `false`.
2015     let is_visible_from_parent_mod = visibility.is_accessible_from(parent_mod.to_def_id(), cx.tcx)
2016         && !current_mod.is_top_level_module();
2017
2018     if pub_underscore {
2019         if let Some(ref inline) = inline_attr {
2020             rustc_errors::struct_span_err!(
2021                 cx.tcx.sess,
2022                 inline.span(),
2023                 E0780,
2024                 "anonymous imports cannot be inlined"
2025             )
2026             .span_label(import.span, "anonymous import")
2027             .emit();
2028         }
2029     }
2030
2031     // We consider inlining the documentation of `pub use` statements, but we
2032     // forcefully don't inline if this is not public or if the
2033     // #[doc(no_inline)] attribute is present.
2034     // Don't inline doc(hidden) imports so they can be stripped at a later stage.
2035     let mut denied = !(visibility.is_public()
2036         || (cx.render_options.document_private && is_visible_from_parent_mod))
2037         || pub_underscore
2038         || attrs.iter().any(|a| {
2039             a.has_name(sym::doc)
2040                 && match a.meta_item_list() {
2041                     Some(l) => {
2042                         attr::list_contains_name(&l, sym::no_inline)
2043                             || attr::list_contains_name(&l, sym::hidden)
2044                     }
2045                     None => false,
2046                 }
2047         });
2048
2049     // Also check whether imports were asked to be inlined, in case we're trying to re-export a
2050     // crate in Rust 2018+
2051     let path = path.clean(cx);
2052     let inner = if kind == hir::UseKind::Glob {
2053         if !denied {
2054             let mut visited = FxHashSet::default();
2055             if let Some(items) = inline::try_inline_glob(cx, path.res, &mut visited) {
2056                 return items;
2057             }
2058         }
2059         Import::new_glob(resolve_use_source(cx, path), true)
2060     } else {
2061         if inline_attr.is_none() {
2062             if let Res::Def(DefKind::Mod, did) = path.res {
2063                 if !did.is_local() && did.index == CRATE_DEF_INDEX {
2064                     // if we're `pub use`ing an extern crate root, don't inline it unless we
2065                     // were specifically asked for it
2066                     denied = true;
2067                 }
2068             }
2069         }
2070         if !denied {
2071             let mut visited = FxHashSet::default();
2072             let import_def_id = import.def_id.to_def_id();
2073
2074             if let Some(mut items) = inline::try_inline(
2075                 cx,
2076                 cx.tcx.parent_module(import.hir_id()).to_def_id(),
2077                 Some(import_def_id),
2078                 path.res,
2079                 name,
2080                 Some(attrs),
2081                 &mut visited,
2082             ) {
2083                 items.push(Item::from_def_id_and_parts(
2084                     import_def_id,
2085                     None,
2086                     ImportItem(Import::new_simple(name, resolve_use_source(cx, path), false)),
2087                     cx,
2088                 ));
2089                 return items;
2090             }
2091         }
2092         Import::new_simple(name, resolve_use_source(cx, path), true)
2093     };
2094
2095     vec![Item::from_def_id_and_parts(import.def_id.to_def_id(), None, ImportItem(inner), cx)]
2096 }
2097
2098 fn clean_maybe_renamed_foreign_item(
2099     cx: &mut DocContext<'_>,
2100     item: &hir::ForeignItem<'_>,
2101     renamed: Option<Symbol>,
2102 ) -> Item {
2103     let def_id = item.def_id.to_def_id();
2104     cx.with_param_env(def_id, |cx| {
2105         let kind = match item.kind {
2106             hir::ForeignItemKind::Fn(decl, names, ref generics) => {
2107                 let abi = cx.tcx.hir().get_foreign_abi(item.hir_id());
2108                 let (generics, decl) = enter_impl_trait(cx, |cx| {
2109                     // NOTE: generics must be cleaned before args
2110                     let generics = generics.clean(cx);
2111                     let args = clean_args_from_types_and_names(cx, decl.inputs, names);
2112                     let decl = clean_fn_decl_with_args(cx, decl, args);
2113                     (generics, decl)
2114                 });
2115                 ForeignFunctionItem(Function {
2116                     decl,
2117                     generics,
2118                     header: hir::FnHeader {
2119                         unsafety: if abi == Abi::RustIntrinsic {
2120                             intrinsic_operation_unsafety(item.ident.name)
2121                         } else {
2122                             hir::Unsafety::Unsafe
2123                         },
2124                         abi,
2125                         constness: hir::Constness::NotConst,
2126                         asyncness: hir::IsAsync::NotAsync,
2127                     },
2128                 })
2129             }
2130             hir::ForeignItemKind::Static(ref ty, mutability) => {
2131                 ForeignStaticItem(Static { type_: ty.clean(cx), mutability, expr: None })
2132             }
2133             hir::ForeignItemKind::Type => ForeignTypeItem,
2134         };
2135
2136         Item::from_hir_id_and_parts(
2137             item.hir_id(),
2138             Some(renamed.unwrap_or(item.ident.name)),
2139             kind,
2140             cx,
2141         )
2142     })
2143 }
2144
2145 impl Clean<TypeBinding> for hir::TypeBinding<'_> {
2146     fn clean(&self, cx: &mut DocContext<'_>) -> TypeBinding {
2147         TypeBinding { name: self.ident.name, kind: self.kind.clean(cx) }
2148     }
2149 }
2150
2151 impl Clean<TypeBindingKind> for hir::TypeBindingKind<'_> {
2152     fn clean(&self, cx: &mut DocContext<'_>) -> TypeBindingKind {
2153         match *self {
2154             hir::TypeBindingKind::Equality { ref term } => {
2155                 TypeBindingKind::Equality { term: term.clean(cx) }
2156             }
2157             hir::TypeBindingKind::Constraint { ref bounds } => TypeBindingKind::Constraint {
2158                 bounds: bounds.iter().filter_map(|b| b.clean(cx)).collect(),
2159             },
2160         }
2161     }
2162 }