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 simplify;
   9 crate mod types;
  10 crate mod utils;
  11
  12 use rustc_ast as ast;
  13 use rustc_attr as attr;
  14 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
  15 use rustc_hir as hir;
  16 use rustc_hir::def::{CtorKind, DefKind, Res};
  17 use rustc_hir::def_id::{CrateNum, DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
  18 use rustc_index::vec::{Idx, IndexVec};
  19 use rustc_infer::infer::region_constraints::{Constraint, RegionConstraintData};
  20 use rustc_middle::bug;
  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, Lift, Ty, TyCtxt};
  25 use rustc_mir::const_eval::{is_const_fn, is_min_const_fn, is_unstable_const_fn};
  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_typeck::hir_ty_to_ty;
  30
  31 use std::collections::hash_map::Entry;
  32 use std::default::Default;
  33 use std::hash::Hash;
  34 use std::rc::Rc;
  35 use std::{mem, vec};
  36
  37 use crate::core::{self, DocContext, ImplTraitParam};
  38 use crate::doctree;
  39
  40 use utils::*;
  41
  42 crate use utils::{get_auto_trait_and_blanket_impls, krate, register_res};
  43
  44 crate use self::types::FnRetTy::*;
  45 crate use self::types::ItemKind::*;
  46 crate use self::types::SelfTy::*;
  47 crate use self::types::Type::*;
  48 crate use self::types::Visibility::{Inherited, Public};
  49 crate use self::types::*;
  50
  51 crate trait Clean<T> {
  52     fn clean(&self, cx: &DocContext<'_>) -> T;
  53 }
  54
  55 impl<T: Clean<U>, U> Clean<Vec<U>> for [T] {
  56     fn clean(&self, cx: &DocContext<'_>) -> Vec<U> {
  57         self.iter().map(|x| x.clean(cx)).collect()
  58     }
  59 }
  60
  61 impl<T: Clean<U>, U, V: Idx> Clean<IndexVec<V, U>> for IndexVec<V, T> {
  62     fn clean(&self, cx: &DocContext<'_>) -> IndexVec<V, U> {
  63         self.iter().map(|x| x.clean(cx)).collect()
  64     }
  65 }
  66
  67 impl<T: Clean<U>, U> Clean<U> for &T {
  68     fn clean(&self, cx: &DocContext<'_>) -> U {
  69         (**self).clean(cx)
  70     }
  71 }
  72
  73 impl<T: Clean<U>, U> Clean<U> for Rc<T> {
  74     fn clean(&self, cx: &DocContext<'_>) -> U {
  75         (**self).clean(cx)
  76     }
  77 }
  78
  79 impl<T: Clean<U>, U> Clean<Option<U>> for Option<T> {
  80     fn clean(&self, cx: &DocContext<'_>) -> Option<U> {
  81         self.as_ref().map(|v| v.clean(cx))
  82     }
  83 }
  84
  85 impl Clean<ExternalCrate> for CrateNum {
  86     fn clean(&self, cx: &DocContext<'_>) -> ExternalCrate {
  87         let root = DefId { krate: *self, index: CRATE_DEF_INDEX };
  88         let krate_span = cx.tcx.def_span(root);
  89         let krate_src = cx.sess().source_map().span_to_filename(krate_span);
  90
  91         // Collect all inner modules which are tagged as implementations of
  92         // primitives.
  93         //
  94         // Note that this loop only searches the top-level items of the crate,
  95         // and this is intentional. If we were to search the entire crate for an
  96         // item tagged with `#[doc(primitive)]` then we would also have to
  97         // search the entirety of external modules for items tagged
  98         // `#[doc(primitive)]`, which is a pretty inefficient process (decoding
  99         // all that metadata unconditionally).
 100         //
 101         // In order to keep the metadata load under control, the
 102         // `#[doc(primitive)]` feature is explicitly designed to only allow the
 103         // primitive tags to show up as the top level items in a crate.
 104         //
 105         // Also note that this does not attempt to deal with modules tagged
 106         // duplicately for the same primitive. This is handled later on when
 107         // rendering by delegating everything to a hash map.
 108         let as_primitive = |res: Res| {
 109             if let Res::Def(DefKind::Mod, def_id) = res {
 110                 let attrs = cx.tcx.get_attrs(def_id).clean(cx);
 111                 let mut prim = None;
 112                 for attr in attrs.lists(sym::doc) {
 113                     if let Some(v) = attr.value_str() {
 114                         if attr.has_name(sym::primitive) {
 115                             prim = PrimitiveType::from_symbol(v);
 116                             if prim.is_some() {
 117                                 break;
 118                             }
 119                             // FIXME: should warn on unknown primitives?
 120                         }
 121                     }
 122                 }
 123                 return prim.map(|p| (def_id, p));
 124             }
 125             None
 126         };
 127         let primitives = if root.is_local() {
 128             cx.tcx
 129                 .hir()
 130                 .krate()
 131                 .item
 132                 .module
 133                 .item_ids
 134                 .iter()
 135                 .filter_map(|&id| {
 136                     let item = cx.tcx.hir().expect_item(id.id);
 137                     match item.kind {
 138                         hir::ItemKind::Mod(_) => as_primitive(Res::Def(
 139                             DefKind::Mod,
 140                             cx.tcx.hir().local_def_id(id.id).to_def_id(),
 141                         )),
 142                         hir::ItemKind::Use(ref path, hir::UseKind::Single)
 143                             if item.vis.node.is_pub() =>
 144                         {
 145                             as_primitive(path.res).map(|(_, prim)| {
 146                                 // Pretend the primitive is local.
 147                                 (cx.tcx.hir().local_def_id(id.id).to_def_id(), prim)
 148                             })
 149                         }
 150                         _ => None,
 151                     }
 152                 })
 153                 .collect()
 154         } else {
 155             cx.tcx
 156                 .item_children(root)
 157                 .iter()
 158                 .map(|item| item.res)
 159                 .filter_map(as_primitive)
 160                 .collect()
 161         };
 162
 163         let as_keyword = |res: Res| {
 164             if let Res::Def(DefKind::Mod, def_id) = res {
 165                 let attrs = cx.tcx.get_attrs(def_id).clean(cx);
 166                 let mut keyword = None;
 167                 for attr in attrs.lists(sym::doc) {
 168                     if attr.has_name(sym::keyword) {
 169                         if let Some(v) = attr.value_str() {
 170                             keyword = Some(v);
 171                             break;
 172                         }
 173                     }
 174                 }
 175                 return keyword.map(|p| (def_id, p));
 176             }
 177             None
 178         };
 179         let keywords = if root.is_local() {
 180             cx.tcx
 181                 .hir()
 182                 .krate()
 183                 .item
 184                 .module
 185                 .item_ids
 186                 .iter()
 187                 .filter_map(|&id| {
 188                     let item = cx.tcx.hir().expect_item(id.id);
 189                     match item.kind {
 190                         hir::ItemKind::Mod(_) => as_keyword(Res::Def(
 191                             DefKind::Mod,
 192                             cx.tcx.hir().local_def_id(id.id).to_def_id(),
 193                         )),
 194                         hir::ItemKind::Use(ref path, hir::UseKind::Single)
 195                             if item.vis.node.is_pub() =>
 196                         {
 197                             as_keyword(path.res).map(|(_, prim)| {
 198                                 (cx.tcx.hir().local_def_id(id.id).to_def_id(), prim)
 199                             })
 200                         }
 201                         _ => None,
 202                     }
 203                 })
 204                 .collect()
 205         } else {
 206             cx.tcx.item_children(root).iter().map(|item| item.res).filter_map(as_keyword).collect()
 207         };
 208
 209         ExternalCrate {
 210             name: cx.tcx.crate_name(*self),
 211             src: krate_src,
 212             attrs: cx.tcx.get_attrs(root).clean(cx),
 213             primitives,
 214             keywords,
 215         }
 216     }
 217 }
 218
 219 impl Clean<Item> for doctree::Module<'_> {
 220     fn clean(&self, cx: &DocContext<'_>) -> Item {
 221         let mut items: Vec<Item> = vec![];
 222         items.extend(self.imports.iter().flat_map(|x| x.clean(cx)));
 223         items.extend(self.foreigns.iter().map(|x| x.clean(cx)));
 224         items.extend(self.mods.iter().map(|x| x.clean(cx)));
 225         items.extend(self.items.iter().map(|x| x.clean(cx)).flatten());
 226         items.extend(self.macros.iter().map(|x| x.clean(cx)));
 227
 228         // determine if we should display the inner contents or
 229         // the outer `mod` item for the source code.
 230         let span = {
 231             let sm = cx.sess().source_map();
 232             let outer = sm.lookup_char_pos(self.where_outer.lo());
 233             let inner = sm.lookup_char_pos(self.where_inner.lo());
 234             if outer.file.start_pos == inner.file.start_pos {
 235                 // mod foo { ... }
 236                 self.where_outer
 237             } else {
 238                 // mod foo; (and a separate SourceFile for the contents)
 239                 self.where_inner
 240             }
 241         };
 242
 243         let what_rustc_thinks = Item::from_hir_id_and_parts(
 244             self.id,
 245             self.name,
 246             ModuleItem(Module { is_crate: self.is_crate, items }),
 247             cx,
 248         );
 249         Item { source: span.clean(cx), ..what_rustc_thinks }
 250     }
 251 }
 252
 253 impl Clean<Attributes> for [ast::Attribute] {
 254     fn clean(&self, cx: &DocContext<'_>) -> Attributes {
 255         Attributes::from_ast(cx.sess().diagnostic(), self, None)
 256     }
 257 }
 258
 259 impl Clean<GenericBound> for hir::GenericBound<'_> {
 260     fn clean(&self, cx: &DocContext<'_>) -> GenericBound {
 261         match *self {
 262             hir::GenericBound::Outlives(lt) => GenericBound::Outlives(lt.clean(cx)),
 263             hir::GenericBound::LangItemTrait(lang_item, span, _, generic_args) => {
 264                 let def_id = cx.tcx.require_lang_item(lang_item, Some(span));
 265
 266                 let trait_ref = ty::TraitRef::identity(cx.tcx, def_id);
 267
 268                 let generic_args = generic_args.clean(cx);
 269                 let bindings = match generic_args {
 270                     GenericArgs::AngleBracketed { bindings, .. } => bindings,
 271                     _ => bug!("clean: parenthesized `GenericBound::LangItemTrait`"),
 272                 };
 273
 274                 GenericBound::TraitBound(
 275                     PolyTrait { trait_: (trait_ref, &*bindings).clean(cx), generic_params: vec![] },
 276                     hir::TraitBoundModifier::None,
 277                 )
 278             }
 279             hir::GenericBound::Trait(ref t, modifier) => {
 280                 GenericBound::TraitBound(t.clean(cx), modifier)
 281             }
 282         }
 283     }
 284 }
 285
 286 impl Clean<Type> for (ty::TraitRef<'_>, &[TypeBinding]) {
 287     fn clean(&self, cx: &DocContext<'_>) -> Type {
 288         let (trait_ref, bounds) = *self;
 289         inline::record_extern_fqn(cx, trait_ref.def_id, TypeKind::Trait);
 290         let path = external_path(
 291             cx,
 292             cx.tcx.item_name(trait_ref.def_id),
 293             Some(trait_ref.def_id),
 294             true,
 295             bounds.to_vec(),
 296             trait_ref.substs,
 297         );
 298
 299         debug!("ty::TraitRef\n  subst: {:?}\n", trait_ref.substs);
 300
 301         ResolvedPath { path, param_names: None, did: trait_ref.def_id, is_generic: false }
 302     }
 303 }
 304
 305 impl<'tcx> Clean<GenericBound> for ty::TraitRef<'tcx> {
 306     fn clean(&self, cx: &DocContext<'_>) -> GenericBound {
 307         GenericBound::TraitBound(
 308             PolyTrait { trait_: (*self, &[][..]).clean(cx), generic_params: vec![] },
 309             hir::TraitBoundModifier::None,
 310         )
 311     }
 312 }
 313
 314 impl Clean<GenericBound> for (ty::PolyTraitRef<'_>, &[TypeBinding]) {
 315     fn clean(&self, cx: &DocContext<'_>) -> GenericBound {
 316         let (poly_trait_ref, bounds) = *self;
 317         let poly_trait_ref = poly_trait_ref.lift_to_tcx(cx.tcx).unwrap();
 318
 319         // collect any late bound regions
 320         let late_bound_regions: Vec<_> = cx
 321             .tcx
 322             .collect_referenced_late_bound_regions(&poly_trait_ref)
 323             .into_iter()
 324             .filter_map(|br| match br {
 325                 ty::BrNamed(_, name) => {
 326                     Some(GenericParamDef { name, kind: GenericParamDefKind::Lifetime })
 327                 }
 328                 _ => None,
 329             })
 330             .collect();
 331
 332         GenericBound::TraitBound(
 333             PolyTrait {
 334                 trait_: (poly_trait_ref.skip_binder(), bounds).clean(cx),
 335                 generic_params: late_bound_regions,
 336             },
 337             hir::TraitBoundModifier::None,
 338         )
 339     }
 340 }
 341
 342 impl<'tcx> Clean<GenericBound> for ty::PolyTraitRef<'tcx> {
 343     fn clean(&self, cx: &DocContext<'_>) -> GenericBound {
 344         (*self, &[][..]).clean(cx)
 345     }
 346 }
 347
 348 impl<'tcx> Clean<Option<Vec<GenericBound>>> for InternalSubsts<'tcx> {
 349     fn clean(&self, cx: &DocContext<'_>) -> Option<Vec<GenericBound>> {
 350         let mut v = Vec::new();
 351         v.extend(self.regions().filter_map(|r| r.clean(cx)).map(GenericBound::Outlives));
 352         v.extend(self.types().map(|t| {
 353             GenericBound::TraitBound(
 354                 PolyTrait { trait_: t.clean(cx), generic_params: Vec::new() },
 355                 hir::TraitBoundModifier::None,
 356             )
 357         }));
 358         if !v.is_empty() { Some(v) } else { None }
 359     }
 360 }
 361
 362 impl Clean<Lifetime> for hir::Lifetime {
 363     fn clean(&self, cx: &DocContext<'_>) -> Lifetime {
 364         let def = cx.tcx.named_region(self.hir_id);
 365         match def {
 366             Some(
 367                 rl::Region::EarlyBound(_, node_id, _)
 368                 | rl::Region::LateBound(_, node_id, _)
 369                 | rl::Region::Free(_, node_id),
 370             ) => {
 371                 if let Some(lt) = cx.lt_substs.borrow().get(&node_id).cloned() {
 372                     return lt;
 373                 }
 374             }
 375             _ => {}
 376         }
 377         Lifetime(self.name.ident().name)
 378     }
 379 }
 380
 381 impl Clean<Lifetime> for hir::GenericParam<'_> {
 382     fn clean(&self, _: &DocContext<'_>) -> Lifetime {
 383         match self.kind {
 384             hir::GenericParamKind::Lifetime { .. } => {
 385                 if !self.bounds.is_empty() {
 386                     let mut bounds = self.bounds.iter().map(|bound| match bound {
 387                         hir::GenericBound::Outlives(lt) => lt,
 388                         _ => panic!(),
 389                     });
 390                     let name = bounds.next().expect("no more bounds").name.ident();
 391                     let mut s = format!("{}: {}", self.name.ident(), name);
 392                     for bound in bounds {
 393                         s.push_str(&format!(" + {}", bound.name.ident()));
 394                     }
 395                     Lifetime(Symbol::intern(&s))
 396                 } else {
 397                     Lifetime(self.name.ident().name)
 398                 }
 399             }
 400             _ => panic!(),
 401         }
 402     }
 403 }
 404
 405 impl Clean<Constant> for hir::ConstArg {
 406     fn clean(&self, cx: &DocContext<'_>) -> Constant {
 407         Constant {
 408             type_: cx
 409                 .tcx
 410                 .type_of(cx.tcx.hir().body_owner_def_id(self.value.body).to_def_id())
 411                 .clean(cx),
 412             expr: print_const_expr(cx, self.value.body),
 413             value: None,
 414             is_literal: is_literal_expr(cx, self.value.body.hir_id),
 415         }
 416     }
 417 }
 418
 419 impl Clean<Lifetime> for ty::GenericParamDef {
 420     fn clean(&self, _cx: &DocContext<'_>) -> Lifetime {
 421         Lifetime(self.name)
 422     }
 423 }
 424
 425 impl Clean<Option<Lifetime>> for ty::RegionKind {
 426     fn clean(&self, _cx: &DocContext<'_>) -> Option<Lifetime> {
 427         match *self {
 428             ty::ReStatic => Some(Lifetime::statik()),
 429             ty::ReLateBound(_, ty::BoundRegion { kind: ty::BrNamed(_, name) }) => {
 430                 Some(Lifetime(name))
 431             }
 432             ty::ReEarlyBound(ref data) => Some(Lifetime(data.name)),
 433
 434             ty::ReLateBound(..)
 435             | ty::ReFree(..)
 436             | ty::ReVar(..)
 437             | ty::RePlaceholder(..)
 438             | ty::ReEmpty(_)
 439             | ty::ReErased => {
 440                 debug!("cannot clean region {:?}", self);
 441                 None
 442             }
 443         }
 444     }
 445 }
 446
 447 impl Clean<WherePredicate> for hir::WherePredicate<'_> {
 448     fn clean(&self, cx: &DocContext<'_>) -> WherePredicate {
 449         match *self {
 450             hir::WherePredicate::BoundPredicate(ref wbp) => WherePredicate::BoundPredicate {
 451                 ty: wbp.bounded_ty.clean(cx),
 452                 bounds: wbp.bounds.clean(cx),
 453             },
 454
 455             hir::WherePredicate::RegionPredicate(ref wrp) => WherePredicate::RegionPredicate {
 456                 lifetime: wrp.lifetime.clean(cx),
 457                 bounds: wrp.bounds.clean(cx),
 458             },
 459
 460             hir::WherePredicate::EqPredicate(ref wrp) => {
 461                 WherePredicate::EqPredicate { lhs: wrp.lhs_ty.clean(cx), rhs: wrp.rhs_ty.clean(cx) }
 462             }
 463         }
 464     }
 465 }
 466
 467 impl<'a> Clean<Option<WherePredicate>> for ty::Predicate<'a> {
 468     fn clean(&self, cx: &DocContext<'_>) -> Option<WherePredicate> {
 469         let bound_predicate = self.bound_atom();
 470         match bound_predicate.skip_binder() {
 471             ty::PredicateAtom::Trait(pred, _) => Some(bound_predicate.rebind(pred).clean(cx)),
 472             ty::PredicateAtom::RegionOutlives(pred) => pred.clean(cx),
 473             ty::PredicateAtom::TypeOutlives(pred) => pred.clean(cx),
 474             ty::PredicateAtom::Projection(pred) => Some(pred.clean(cx)),
 475
 476             ty::PredicateAtom::Subtype(..)
 477             | ty::PredicateAtom::WellFormed(..)
 478             | ty::PredicateAtom::ObjectSafe(..)
 479             | ty::PredicateAtom::ClosureKind(..)
 480             | ty::PredicateAtom::ConstEvaluatable(..)
 481             | ty::PredicateAtom::ConstEquate(..)
 482             | ty::PredicateAtom::TypeWellFormedFromEnv(..) => panic!("not user writable"),
 483         }
 484     }
 485 }
 486
 487 impl<'a> Clean<WherePredicate> for ty::PolyTraitPredicate<'a> {
 488     fn clean(&self, cx: &DocContext<'_>) -> WherePredicate {
 489         let poly_trait_ref = self.map_bound(|pred| pred.trait_ref);
 490         WherePredicate::BoundPredicate {
 491             ty: poly_trait_ref.skip_binder().self_ty().clean(cx),
 492             bounds: vec![poly_trait_ref.clean(cx)],
 493         }
 494     }
 495 }
 496
 497 impl<'tcx> Clean<Option<WherePredicate>>
 498     for ty::OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>
 499 {
 500     fn clean(&self, cx: &DocContext<'_>) -> Option<WherePredicate> {
 501         let ty::OutlivesPredicate(a, b) = self;
 502
 503         if let (ty::ReEmpty(_), ty::ReEmpty(_)) = (a, b) {
 504             return None;
 505         }
 506
 507         Some(WherePredicate::RegionPredicate {
 508             lifetime: a.clean(cx).expect("failed to clean lifetime"),
 509             bounds: vec![GenericBound::Outlives(b.clean(cx).expect("failed to clean bounds"))],
 510         })
 511     }
 512 }
 513
 514 impl<'tcx> Clean<Option<WherePredicate>> for ty::OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>> {
 515     fn clean(&self, cx: &DocContext<'_>) -> Option<WherePredicate> {
 516         let ty::OutlivesPredicate(ty, lt) = self;
 517
 518         if let ty::ReEmpty(_) = lt {
 519             return None;
 520         }
 521
 522         Some(WherePredicate::BoundPredicate {
 523             ty: ty.clean(cx),
 524             bounds: vec![GenericBound::Outlives(lt.clean(cx).expect("failed to clean lifetimes"))],
 525         })
 526     }
 527 }
 528
 529 impl<'tcx> Clean<WherePredicate> for ty::ProjectionPredicate<'tcx> {
 530     fn clean(&self, cx: &DocContext<'_>) -> WherePredicate {
 531         let ty::ProjectionPredicate { projection_ty, ty } = self;
 532         WherePredicate::EqPredicate { lhs: projection_ty.clean(cx), rhs: ty.clean(cx) }
 533     }
 534 }
 535
 536 impl<'tcx> Clean<Type> for ty::ProjectionTy<'tcx> {
 537     fn clean(&self, cx: &DocContext<'_>) -> Type {
 538         let lifted = self.lift_to_tcx(cx.tcx).unwrap();
 539         let trait_ = match lifted.trait_ref(cx.tcx).clean(cx) {
 540             GenericBound::TraitBound(t, _) => t.trait_,
 541             GenericBound::Outlives(_) => panic!("cleaning a trait got a lifetime"),
 542         };
 543         Type::QPath {
 544             name: cx.tcx.associated_item(self.item_def_id).ident.name,
 545             self_type: box self.self_ty().clean(cx),
 546             trait_: box trait_,
 547         }
 548     }
 549 }
 550
 551 impl Clean<GenericParamDef> for ty::GenericParamDef {
 552     fn clean(&self, cx: &DocContext<'_>) -> GenericParamDef {
 553         let (name, kind) = match self.kind {
 554             ty::GenericParamDefKind::Lifetime => (self.name, GenericParamDefKind::Lifetime),
 555             ty::GenericParamDefKind::Type { has_default, synthetic, .. } => {
 556                 let default =
 557                     if has_default { Some(cx.tcx.type_of(self.def_id).clean(cx)) } else { None };
 558                 (
 559                     self.name,
 560                     GenericParamDefKind::Type {
 561                         did: self.def_id,
 562                         bounds: vec![], // These are filled in from the where-clauses.
 563                         default,
 564                         synthetic,
 565                     },
 566                 )
 567             }
 568             ty::GenericParamDefKind::Const { .. } => (
 569                 self.name,
 570                 GenericParamDefKind::Const {
 571                     did: self.def_id,
 572                     ty: cx.tcx.type_of(self.def_id).clean(cx),
 573                 },
 574             ),
 575         };
 576
 577         GenericParamDef { name, kind }
 578     }
 579 }
 580
 581 impl Clean<GenericParamDef> for hir::GenericParam<'_> {
 582     fn clean(&self, cx: &DocContext<'_>) -> GenericParamDef {
 583         let (name, kind) = match self.kind {
 584             hir::GenericParamKind::Lifetime { .. } => {
 585                 let name = if !self.bounds.is_empty() {
 586                     let mut bounds = self.bounds.iter().map(|bound| match bound {
 587                         hir::GenericBound::Outlives(lt) => lt,
 588                         _ => panic!(),
 589                     });
 590                     let name = bounds.next().expect("no more bounds").name.ident();
 591                     let mut s = format!("{}: {}", self.name.ident(), name);
 592                     for bound in bounds {
 593                         s.push_str(&format!(" + {}", bound.name.ident()));
 594                     }
 595                     Symbol::intern(&s)
 596                 } else {
 597                     self.name.ident().name
 598                 };
 599                 (name, GenericParamDefKind::Lifetime)
 600             }
 601             hir::GenericParamKind::Type { ref default, synthetic } => (
 602                 self.name.ident().name,
 603                 GenericParamDefKind::Type {
 604                     did: cx.tcx.hir().local_def_id(self.hir_id).to_def_id(),
 605                     bounds: self.bounds.clean(cx),
 606                     default: default.clean(cx),
 607                     synthetic,
 608                 },
 609             ),
 610             hir::GenericParamKind::Const { ref ty, default: _ } => (
 611                 self.name.ident().name,
 612                 GenericParamDefKind::Const {
 613                     did: cx.tcx.hir().local_def_id(self.hir_id).to_def_id(),
 614                     ty: ty.clean(cx),
 615                     // FIXME(const_generics_defaults): add `default` field here for docs
 616                 },
 617             ),
 618         };
 619
 620         GenericParamDef { name, kind }
 621     }
 622 }
 623
 624 impl Clean<Generics> for hir::Generics<'_> {
 625     fn clean(&self, cx: &DocContext<'_>) -> Generics {
 626         // Synthetic type-parameters are inserted after normal ones.
 627         // In order for normal parameters to be able to refer to synthetic ones,
 628         // scans them first.
 629         fn is_impl_trait(param: &hir::GenericParam<'_>) -> bool {
 630             match param.kind {
 631                 hir::GenericParamKind::Type { synthetic, .. } => {
 632                     synthetic == Some(hir::SyntheticTyParamKind::ImplTrait)
 633                 }
 634                 _ => false,
 635             }
 636         }
 637         /// This can happen for `async fn`, e.g. `async fn f<'_>(&'_ self)`.
 638         ///
 639         /// See [`lifetime_to_generic_param`] in [`rustc_ast_lowering`] for more information.
 640         ///
 641         /// [`lifetime_to_generic_param`]: rustc_ast_lowering::LoweringContext::lifetime_to_generic_param
 642         fn is_elided_lifetime(param: &hir::GenericParam<'_>) -> bool {
 643             matches!(
 644                 param.kind,
 645                 hir::GenericParamKind::Lifetime { kind: hir::LifetimeParamKind::Elided }
 646             )
 647         }
 648
 649         let impl_trait_params = self
 650             .params
 651             .iter()
 652             .filter(|param| is_impl_trait(param))
 653             .map(|param| {
 654                 let param: GenericParamDef = param.clean(cx);
 655                 match param.kind {
 656                     GenericParamDefKind::Lifetime => unreachable!(),
 657                     GenericParamDefKind::Type { did, ref bounds, .. } => {
 658                         cx.impl_trait_bounds.borrow_mut().insert(did.into(), bounds.clone());
 659                     }
 660                     GenericParamDefKind::Const { .. } => unreachable!(),
 661                 }
 662                 param
 663             })
 664             .collect::<Vec<_>>();
 665
 666         let mut params = Vec::with_capacity(self.params.len());
 667         for p in self.params.iter().filter(|p| !is_impl_trait(p) && !is_elided_lifetime(p)) {
 668             let p = p.clean(cx);
 669             params.push(p);
 670         }
 671         params.extend(impl_trait_params);
 672
 673         let mut generics =
 674             Generics { params, where_predicates: self.where_clause.predicates.clean(cx) };
 675
 676         // Some duplicates are generated for ?Sized bounds between type params and where
 677         // predicates. The point in here is to move the bounds definitions from type params
 678         // to where predicates when such cases occur.
 679         for where_pred in &mut generics.where_predicates {
 680             match *where_pred {
 681                 WherePredicate::BoundPredicate { ty: Generic(ref name), ref mut bounds } => {
 682                     if bounds.is_empty() {
 683                         for param in &mut generics.params {
 684                             match param.kind {
 685                                 GenericParamDefKind::Lifetime => {}
 686                                 GenericParamDefKind::Type { bounds: ref mut ty_bounds, .. } => {
 687                                     if &param.name == name {
 688                                         mem::swap(bounds, ty_bounds);
 689                                         break;
 690                                     }
 691                                 }
 692                                 GenericParamDefKind::Const { .. } => {}
 693                             }
 694                         }
 695                     }
 696                 }
 697                 _ => continue,
 698             }
 699         }
 700         generics
 701     }
 702 }
 703
 704 impl<'a, 'tcx> Clean<Generics> for (&'a ty::Generics, ty::GenericPredicates<'tcx>) {
 705     fn clean(&self, cx: &DocContext<'_>) -> Generics {
 706         use self::WherePredicate as WP;
 707         use std::collections::BTreeMap;
 708
 709         let (gens, preds) = *self;
 710
 711         // Don't populate `cx.impl_trait_bounds` before `clean`ning `where` clauses,
 712         // since `Clean for ty::Predicate` would consume them.
 713         let mut impl_trait = BTreeMap::<ImplTraitParam, Vec<GenericBound>>::default();
 714
 715         // Bounds in the type_params and lifetimes fields are repeated in the
 716         // predicates field (see rustc_typeck::collect::ty_generics), so remove
 717         // them.
 718         let stripped_params = gens
 719             .params
 720             .iter()
 721             .filter_map(|param| match param.kind {
 722                 ty::GenericParamDefKind::Lifetime => Some(param.clean(cx)),
 723                 ty::GenericParamDefKind::Type { synthetic, .. } => {
 724                     if param.name == kw::SelfUpper {
 725                         assert_eq!(param.index, 0);
 726                         return None;
 727                     }
 728                     if synthetic == Some(hir::SyntheticTyParamKind::ImplTrait) {
 729                         impl_trait.insert(param.index.into(), vec![]);
 730                         return None;
 731                     }
 732                     Some(param.clean(cx))
 733                 }
 734                 ty::GenericParamDefKind::Const { .. } => Some(param.clean(cx)),
 735             })
 736             .collect::<Vec<GenericParamDef>>();
 737
 738         // param index -> [(DefId of trait, associated type name, type)]
 739         let mut impl_trait_proj = FxHashMap::<u32, Vec<(DefId, Symbol, Ty<'tcx>)>>::default();
 740
 741         let where_predicates = preds
 742             .predicates
 743             .iter()
 744             .flat_map(|(p, _)| {
 745                 let mut projection = None;
 746                 let param_idx = (|| {
 747                     let bound_p = p.bound_atom();
 748                     match bound_p.skip_binder() {
 749                         ty::PredicateAtom::Trait(pred, _constness) => {
 750                             if let ty::Param(param) = pred.self_ty().kind() {
 751                                 return Some(param.index);
 752                             }
 753                         }
 754                         ty::PredicateAtom::TypeOutlives(ty::OutlivesPredicate(ty, _reg)) => {
 755                             if let ty::Param(param) = ty.kind() {
 756                                 return Some(param.index);
 757                             }
 758                         }
 759                         ty::PredicateAtom::Projection(p) => {
 760                             if let ty::Param(param) = p.projection_ty.self_ty().kind() {
 761                                 projection = Some(bound_p.rebind(p));
 762                                 return Some(param.index);
 763                             }
 764                         }
 765                         _ => (),
 766                     }
 767
 768                     None
 769                 })();
 770
 771                 if let Some(param_idx) = param_idx {
 772                     if let Some(b) = impl_trait.get_mut(&param_idx.into()) {
 773                         let p = p.clean(cx)?;
 774
 775                         b.extend(
 776                             p.get_bounds()
 777                                 .into_iter()
 778                                 .flatten()
 779                                 .cloned()
 780                                 .filter(|b| !b.is_sized_bound(cx)),
 781                         );
 782
 783                         let proj = projection
 784                             .map(|p| (p.skip_binder().projection_ty.clean(cx), p.skip_binder().ty));
 785                         if let Some(((_, trait_did, name), rhs)) =
 786                             proj.as_ref().and_then(|(lhs, rhs)| Some((lhs.projection()?, rhs)))
 787                         {
 788                             impl_trait_proj
 789                                 .entry(param_idx)
 790                                 .or_default()
 791                                 .push((trait_did, name, rhs));
 792                         }
 793
 794                         return None;
 795                     }
 796                 }
 797
 798                 Some(p)
 799             })
 800             .collect::<Vec<_>>();
 801
 802         for (param, mut bounds) in impl_trait {
 803             // Move trait bounds to the front.
 804             bounds.sort_by_key(|b| !matches!(b, GenericBound::TraitBound(..)));
 805
 806             if let crate::core::ImplTraitParam::ParamIndex(idx) = param {
 807                 if let Some(proj) = impl_trait_proj.remove(&idx) {
 808                     for (trait_did, name, rhs) in proj {
 809                         simplify::merge_bounds(cx, &mut bounds, trait_did, name, &rhs.clean(cx));
 810                     }
 811                 }
 812             } else {
 813                 unreachable!();
 814             }
 815
 816             cx.impl_trait_bounds.borrow_mut().insert(param, bounds);
 817         }
 818
 819         // Now that `cx.impl_trait_bounds` is populated, we can process
 820         // remaining predicates which could contain `impl Trait`.
 821         let mut where_predicates =
 822             where_predicates.into_iter().flat_map(|p| p.clean(cx)).collect::<Vec<_>>();
 823
 824         // Type parameters have a Sized bound by default unless removed with
 825         // ?Sized. Scan through the predicates and mark any type parameter with
 826         // a Sized bound, removing the bounds as we find them.
 827         //
 828         // Note that associated types also have a sized bound by default, but we
 829         // don't actually know the set of associated types right here so that's
 830         // handled in cleaning associated types
 831         let mut sized_params = FxHashSet::default();
 832         where_predicates.retain(|pred| match *pred {
 833             WP::BoundPredicate { ty: Generic(ref g), ref bounds } => {
 834                 if bounds.iter().any(|b| b.is_sized_bound(cx)) {
 835                     sized_params.insert(*g);
 836                     false
 837                 } else {
 838                     true
 839                 }
 840             }
 841             _ => true,
 842         });
 843
 844         // Run through the type parameters again and insert a ?Sized
 845         // unbound for any we didn't find to be Sized.
 846         for tp in &stripped_params {
 847             if matches!(tp.kind, types::GenericParamDefKind::Type { .. })
 848                 && !sized_params.contains(&tp.name)
 849             {
 850                 where_predicates.push(WP::BoundPredicate {
 851                     ty: Type::Generic(tp.name),
 852                     bounds: vec![GenericBound::maybe_sized(cx)],
 853                 })
 854             }
 855         }
 856
 857         // It would be nice to collect all of the bounds on a type and recombine
 858         // them if possible, to avoid e.g., `where T: Foo, T: Bar, T: Sized, T: 'a`
 859         // and instead see `where T: Foo + Bar + Sized + 'a`
 860
 861         Generics {
 862             params: stripped_params,
 863             where_predicates: simplify::where_clauses(cx, where_predicates),
 864         }
 865     }
 866 }
 867
 868 fn clean_fn_or_proc_macro(
 869     item: &hir::Item<'_>,
 870     sig: &'a hir::FnSig<'a>,
 871     generics: &'a hir::Generics<'a>,
 872     body_id: hir::BodyId,
 873     name: &mut Symbol,
 874     cx: &DocContext<'_>,
 875 ) -> ItemKind {
 876     let macro_kind = item.attrs.iter().find_map(|a| {
 877         if a.has_name(sym::proc_macro) {
 878             Some(MacroKind::Bang)
 879         } else if a.has_name(sym::proc_macro_derive) {
 880             Some(MacroKind::Derive)
 881         } else if a.has_name(sym::proc_macro_attribute) {
 882             Some(MacroKind::Attr)
 883         } else {
 884             None
 885         }
 886     });
 887     match macro_kind {
 888         Some(kind) => {
 889             if kind == MacroKind::Derive {
 890                 *name = item
 891                     .attrs
 892                     .lists(sym::proc_macro_derive)
 893                     .find_map(|mi| mi.ident())
 894                     .expect("proc-macro derives require a name")
 895                     .name;
 896             }
 897
 898             let mut helpers = Vec::new();
 899             for mi in item.attrs.lists(sym::proc_macro_derive) {
 900                 if !mi.has_name(sym::attributes) {
 901                     continue;
 902                 }
 903
 904                 if let Some(list) = mi.meta_item_list() {
 905                     for inner_mi in list {
 906                         if let Some(ident) = inner_mi.ident() {
 907                             helpers.push(ident.name);
 908                         }
 909                     }
 910                 }
 911             }
 912             ProcMacroItem(ProcMacro { kind, helpers })
 913         }
 914         None => {
 915             let mut func = (sig, generics, body_id).clean(cx);
 916             let def_id = cx.tcx.hir().local_def_id(item.hir_id).to_def_id();
 917             func.header.constness =
 918                 if is_const_fn(cx.tcx, def_id) && is_unstable_const_fn(cx.tcx, def_id).is_none() {
 919                     hir::Constness::Const
 920                 } else {
 921                     hir::Constness::NotConst
 922                 };
 923             FunctionItem(func)
 924         }
 925     }
 926 }
 927
 928 impl<'a> Clean<Function> for (&'a hir::FnSig<'a>, &'a hir::Generics<'a>, hir::BodyId) {
 929     fn clean(&self, cx: &DocContext<'_>) -> Function {
 930         let (generics, decl) =
 931             enter_impl_trait(cx, || (self.1.clean(cx), (&*self.0.decl, self.2).clean(cx)));
 932         let (all_types, ret_types) = get_all_types(&generics, &decl, cx);
 933         Function { decl, generics, header: self.0.header, all_types, ret_types }
 934     }
 935 }
 936
 937 impl<'a> Clean<Arguments> for (&'a [hir::Ty<'a>], &'a [Ident]) {
 938     fn clean(&self, cx: &DocContext<'_>) -> Arguments {
 939         Arguments {
 940             values: self
 941                 .0
 942                 .iter()
 943                 .enumerate()
 944                 .map(|(i, ty)| {
 945                     let mut name = self.1.get(i).map_or(kw::Empty, |ident| ident.name);
 946                     if name.is_empty() {
 947                         name = kw::Underscore;
 948                     }
 949                     Argument { name, type_: ty.clean(cx) }
 950                 })
 951                 .collect(),
 952         }
 953     }
 954 }
 955
 956 impl<'a> Clean<Arguments> for (&'a [hir::Ty<'a>], hir::BodyId) {
 957     fn clean(&self, cx: &DocContext<'_>) -> Arguments {
 958         let body = cx.tcx.hir().body(self.1);
 959
 960         Arguments {
 961             values: self
 962                 .0
 963                 .iter()
 964                 .enumerate()
 965                 .map(|(i, ty)| Argument {
 966                     name: Symbol::intern(&rustc_hir_pretty::param_to_string(&body.params[i])),
 967                     type_: ty.clean(cx),
 968                 })
 969                 .collect(),
 970         }
 971     }
 972 }
 973
 974 impl<'a, A: Copy> Clean<FnDecl> for (&'a hir::FnDecl<'a>, A)
 975 where
 976     (&'a [hir::Ty<'a>], A): Clean<Arguments>,
 977 {
 978     fn clean(&self, cx: &DocContext<'_>) -> FnDecl {
 979         FnDecl {
 980             inputs: (&self.0.inputs[..], self.1).clean(cx),
 981             output: self.0.output.clean(cx),
 982             c_variadic: self.0.c_variadic,
 983             attrs: Attributes::default(),
 984         }
 985     }
 986 }
 987
 988 impl<'tcx> Clean<FnDecl> for (DefId, ty::PolyFnSig<'tcx>) {
 989     fn clean(&self, cx: &DocContext<'_>) -> FnDecl {
 990         let (did, sig) = *self;
 991         let mut names = if did.is_local() { &[] } else { cx.tcx.fn_arg_names(did) }.iter();
 992
 993         FnDecl {
 994             output: Return(sig.skip_binder().output().clean(cx)),
 995             attrs: Attributes::default(),
 996             c_variadic: sig.skip_binder().c_variadic,
 997             inputs: Arguments {
 998                 values: sig
 999                     .skip_binder()
1000                     .inputs()
1001                     .iter()
1002                     .map(|t| Argument {
1003                         type_: t.clean(cx),
1004                         name: names.next().map_or(kw::Empty, |i| i.name),
1005                     })
1006                     .collect(),
1007             },
1008         }
1009     }
1010 }
1011
1012 impl Clean<FnRetTy> for hir::FnRetTy<'_> {
1013     fn clean(&self, cx: &DocContext<'_>) -> FnRetTy {
1014         match *self {
1015             Self::Return(ref typ) => Return(typ.clean(cx)),
1016             Self::DefaultReturn(..) => DefaultReturn,
1017         }
1018     }
1019 }
1020
1021 impl Clean<bool> for hir::IsAuto {
1022     fn clean(&self, _: &DocContext<'_>) -> bool {
1023         match *self {
1024             hir::IsAuto::Yes => true,
1025             hir::IsAuto::No => false,
1026         }
1027     }
1028 }
1029
1030 impl Clean<Type> for hir::TraitRef<'_> {
1031     fn clean(&self, cx: &DocContext<'_>) -> Type {
1032         resolve_type(cx, self.path.clean(cx), self.hir_ref_id)
1033     }
1034 }
1035
1036 impl Clean<PolyTrait> for hir::PolyTraitRef<'_> {
1037     fn clean(&self, cx: &DocContext<'_>) -> PolyTrait {
1038         PolyTrait {
1039             trait_: self.trait_ref.clean(cx),
1040             generic_params: self.bound_generic_params.clean(cx),
1041         }
1042     }
1043 }
1044
1045 impl Clean<TypeKind> for hir::def::DefKind {
1046     fn clean(&self, _: &DocContext<'_>) -> TypeKind {
1047         match *self {
1048             hir::def::DefKind::Mod => TypeKind::Module,
1049             hir::def::DefKind::Struct => TypeKind::Struct,
1050             hir::def::DefKind::Union => TypeKind::Union,
1051             hir::def::DefKind::Enum => TypeKind::Enum,
1052             hir::def::DefKind::Trait => TypeKind::Trait,
1053             hir::def::DefKind::TyAlias => TypeKind::Typedef,
1054             hir::def::DefKind::ForeignTy => TypeKind::Foreign,
1055             hir::def::DefKind::TraitAlias => TypeKind::TraitAlias,
1056             hir::def::DefKind::Fn => TypeKind::Function,
1057             hir::def::DefKind::Const => TypeKind::Const,
1058             hir::def::DefKind::Static => TypeKind::Static,
1059             hir::def::DefKind::Macro(_) => TypeKind::Macro,
1060             _ => TypeKind::Foreign,
1061         }
1062     }
1063 }
1064
1065 impl Clean<Item> for hir::TraitItem<'_> {
1066     fn clean(&self, cx: &DocContext<'_>) -> Item {
1067         let local_did = cx.tcx.hir().local_def_id(self.hir_id).to_def_id();
1068         cx.with_param_env(local_did, || {
1069             let inner = match self.kind {
1070                 hir::TraitItemKind::Const(ref ty, default) => {
1071                     AssocConstItem(ty.clean(cx), default.map(|e| print_const_expr(cx, e)))
1072                 }
1073                 hir::TraitItemKind::Fn(ref sig, hir::TraitFn::Provided(body)) => {
1074                     let mut m = (sig, &self.generics, body).clean(cx);
1075                     if m.header.constness == hir::Constness::Const
1076                         && is_unstable_const_fn(cx.tcx, local_did).is_some()
1077                     {
1078                         m.header.constness = hir::Constness::NotConst;
1079                     }
1080                     MethodItem(m, None)
1081                 }
1082                 hir::TraitItemKind::Fn(ref sig, hir::TraitFn::Required(ref names)) => {
1083                     let (generics, decl) = enter_impl_trait(cx, || {
1084                         (self.generics.clean(cx), (&*sig.decl, &names[..]).clean(cx))
1085                     });
1086                     let (all_types, ret_types) = get_all_types(&generics, &decl, cx);
1087                     let mut t =
1088                         Function { header: sig.header, decl, generics, all_types, ret_types };
1089                     if t.header.constness == hir::Constness::Const
1090                         && is_unstable_const_fn(cx.tcx, local_did).is_some()
1091                     {
1092                         t.header.constness = hir::Constness::NotConst;
1093                     }
1094                     TyMethodItem(t)
1095                 }
1096                 hir::TraitItemKind::Type(ref bounds, ref default) => {
1097                     AssocTypeItem(bounds.clean(cx), default.clean(cx))
1098                 }
1099             };
1100             Item::from_def_id_and_parts(local_did, Some(self.ident.name), inner, cx)
1101         })
1102     }
1103 }
1104
1105 impl Clean<Item> for hir::ImplItem<'_> {
1106     fn clean(&self, cx: &DocContext<'_>) -> Item {
1107         let local_did = cx.tcx.hir().local_def_id(self.hir_id).to_def_id();
1108         cx.with_param_env(local_did, || {
1109             let inner = match self.kind {
1110                 hir::ImplItemKind::Const(ref ty, expr) => {
1111                     AssocConstItem(ty.clean(cx), Some(print_const_expr(cx, expr)))
1112                 }
1113                 hir::ImplItemKind::Fn(ref sig, body) => {
1114                     let mut m = (sig, &self.generics, body).clean(cx);
1115                     if m.header.constness == hir::Constness::Const
1116                         && is_unstable_const_fn(cx.tcx, local_did).is_some()
1117                     {
1118                         m.header.constness = hir::Constness::NotConst;
1119                     }
1120                     MethodItem(m, Some(self.defaultness))
1121                 }
1122                 hir::ImplItemKind::TyAlias(ref hir_ty) => {
1123                     let type_ = hir_ty.clean(cx);
1124                     let item_type = hir_ty_to_ty(cx.tcx, hir_ty).clean(cx);
1125                     TypedefItem(
1126                         Typedef {
1127                             type_,
1128                             generics: Generics::default(),
1129                             item_type: Some(item_type),
1130                         },
1131                         true,
1132                     )
1133                 }
1134             };
1135             Item::from_def_id_and_parts(local_did, Some(self.ident.name), inner, cx)
1136         })
1137     }
1138 }
1139
1140 impl Clean<Item> for ty::AssocItem {
1141     fn clean(&self, cx: &DocContext<'_>) -> Item {
1142         let kind = match self.kind {
1143             ty::AssocKind::Const => {
1144                 let ty = cx.tcx.type_of(self.def_id);
1145                 let default = if self.defaultness.has_value() {
1146                     Some(inline::print_inlined_const(cx, self.def_id))
1147                 } else {
1148                     None
1149                 };
1150                 AssocConstItem(ty.clean(cx), default)
1151             }
1152             ty::AssocKind::Fn => {
1153                 let generics =
1154                     (cx.tcx.generics_of(self.def_id), cx.tcx.explicit_predicates_of(self.def_id))
1155                         .clean(cx);
1156                 let sig = cx.tcx.fn_sig(self.def_id);
1157                 let mut decl = (self.def_id, sig).clean(cx);
1158
1159                 if self.fn_has_self_parameter {
1160                     let self_ty = match self.container {
1161                         ty::ImplContainer(def_id) => cx.tcx.type_of(def_id),
1162                         ty::TraitContainer(_) => cx.tcx.types.self_param,
1163                     };
1164                     let self_arg_ty = sig.input(0).skip_binder();
1165                     if self_arg_ty == self_ty {
1166                         decl.inputs.values[0].type_ = Generic(kw::SelfUpper);
1167                     } else if let ty::Ref(_, ty, _) = *self_arg_ty.kind() {
1168                         if ty == self_ty {
1169                             match decl.inputs.values[0].type_ {
1170                                 BorrowedRef { ref mut type_, .. } => {
1171                                     **type_ = Generic(kw::SelfUpper)
1172                                 }
1173                                 _ => unreachable!(),
1174                             }
1175                         }
1176                     }
1177                 }
1178
1179                 let provided = match self.container {
1180                     ty::ImplContainer(_) => true,
1181                     ty::TraitContainer(_) => self.defaultness.has_value(),
1182                 };
1183                 let (all_types, ret_types) = get_all_types(&generics, &decl, cx);
1184                 if provided {
1185                     let constness = if is_min_const_fn(cx.tcx, self.def_id) {
1186                         hir::Constness::Const
1187                     } else {
1188                         hir::Constness::NotConst
1189                     };
1190                     let asyncness = cx.tcx.asyncness(self.def_id);
1191                     let defaultness = match self.container {
1192                         ty::ImplContainer(_) => Some(self.defaultness),
1193                         ty::TraitContainer(_) => None,
1194                     };
1195                     MethodItem(
1196                         Function {
1197                             generics,
1198                             decl,
1199                             header: hir::FnHeader {
1200                                 unsafety: sig.unsafety(),
1201                                 abi: sig.abi(),
1202                                 constness,
1203                                 asyncness,
1204                             },
1205                             all_types,
1206                             ret_types,
1207                         },
1208                         defaultness,
1209                     )
1210                 } else {
1211                     TyMethodItem(Function {
1212                         generics,
1213                         decl,
1214                         header: hir::FnHeader {
1215                             unsafety: sig.unsafety(),
1216                             abi: sig.abi(),
1217                             constness: hir::Constness::NotConst,
1218                             asyncness: hir::IsAsync::NotAsync,
1219                         },
1220                         all_types,
1221                         ret_types,
1222                     })
1223                 }
1224             }
1225             ty::AssocKind::Type => {
1226                 let my_name = self.ident.name;
1227
1228                 if let ty::TraitContainer(_) = self.container {
1229                     let bounds = cx.tcx.explicit_item_bounds(self.def_id);
1230                     let predicates = ty::GenericPredicates { parent: None, predicates: bounds };
1231                     let generics = (cx.tcx.generics_of(self.def_id), predicates).clean(cx);
1232                     let mut bounds = generics
1233                         .where_predicates
1234                         .iter()
1235                         .filter_map(|pred| {
1236                             let (name, self_type, trait_, bounds) = match *pred {
1237                                 WherePredicate::BoundPredicate {
1238                                     ty: QPath { ref name, ref self_type, ref trait_ },
1239                                     ref bounds,
1240                                 } => (name, self_type, trait_, bounds),
1241                                 _ => return None,
1242                             };
1243                             if *name != my_name {
1244                                 return None;
1245                             }
1246                             match **trait_ {
1247                                 ResolvedPath { did, .. } if did == self.container.id() => {}
1248                                 _ => return None,
1249                             }
1250                             match **self_type {
1251                                 Generic(ref s) if *s == kw::SelfUpper => {}
1252                                 _ => return None,
1253                             }
1254                             Some(bounds)
1255                         })
1256                         .flat_map(|i| i.iter().cloned())
1257                         .collect::<Vec<_>>();
1258                     // Our Sized/?Sized bound didn't get handled when creating the generics
1259                     // because we didn't actually get our whole set of bounds until just now
1260                     // (some of them may have come from the trait). If we do have a sized
1261                     // bound, we remove it, and if we don't then we add the `?Sized` bound
1262                     // at the end.
1263                     match bounds.iter().position(|b| b.is_sized_bound(cx)) {
1264                         Some(i) => {
1265                             bounds.remove(i);
1266                         }
1267                         None => bounds.push(GenericBound::maybe_sized(cx)),
1268                     }
1269
1270                     let ty = if self.defaultness.has_value() {
1271                         Some(cx.tcx.type_of(self.def_id))
1272                     } else {
1273                         None
1274                     };
1275
1276                     AssocTypeItem(bounds, ty.clean(cx))
1277                 } else {
1278                     // FIXME: when could this happen? ASsociated items in inherent impls?
1279                     let type_ = cx.tcx.type_of(self.def_id).clean(cx);
1280                     TypedefItem(
1281                         Typedef {
1282                             type_,
1283                             generics: Generics { params: Vec::new(), where_predicates: Vec::new() },
1284                             item_type: None,
1285                         },
1286                         true,
1287                     )
1288                 }
1289             }
1290         };
1291
1292         Item::from_def_id_and_parts(self.def_id, Some(self.ident.name), kind, cx)
1293     }
1294 }
1295
1296 fn clean_qpath(hir_ty: &hir::Ty<'_>, cx: &DocContext<'_>) -> Type {
1297     use rustc_hir::GenericParamCount;
1298     let hir::Ty { hir_id, span, ref kind } = *hir_ty;
1299     let qpath = match kind {
1300         hir::TyKind::Path(qpath) => qpath,
1301         _ => unreachable!(),
1302     };
1303
1304     match qpath {
1305         hir::QPath::Resolved(None, ref path) => {
1306             if let Res::Def(DefKind::TyParam, did) = path.res {
1307                 if let Some(new_ty) = cx.ty_substs.borrow().get(&did).cloned() {
1308                     return new_ty;
1309                 }
1310                 if let Some(bounds) = cx.impl_trait_bounds.borrow_mut().remove(&did.into()) {
1311                     return ImplTrait(bounds);
1312                 }
1313             }
1314
1315             let mut alias = None;
1316             if let Res::Def(DefKind::TyAlias, def_id) = path.res {
1317                 // Substitute private type aliases
1318                 if let Some(def_id) = def_id.as_local() {
1319                     let hir_id = cx.tcx.hir().local_def_id_to_hir_id(def_id);
1320                     if !cx.renderinfo.borrow().access_levels.is_exported(def_id.to_def_id()) {
1321                         alias = Some(&cx.tcx.hir().expect_item(hir_id).kind);
1322                     }
1323                 }
1324             };
1325
1326             if let Some(&hir::ItemKind::TyAlias(ref ty, ref generics)) = alias {
1327                 let provided_params = &path.segments.last().expect("segments were empty");
1328                 let mut ty_substs = FxHashMap::default();
1329                 let mut lt_substs = FxHashMap::default();
1330                 let mut ct_substs = FxHashMap::default();
1331                 let generic_args = provided_params.generic_args();
1332                 {
1333                     let mut indices: GenericParamCount = Default::default();
1334                     for param in generics.params.iter() {
1335                         match param.kind {
1336                             hir::GenericParamKind::Lifetime { .. } => {
1337                                 let mut j = 0;
1338                                 let lifetime = generic_args.args.iter().find_map(|arg| match arg {
1339                                     hir::GenericArg::Lifetime(lt) => {
1340                                         if indices.lifetimes == j {
1341                                             return Some(lt);
1342                                         }
1343                                         j += 1;
1344                                         None
1345                                     }
1346                                     _ => None,
1347                                 });
1348                                 if let Some(lt) = lifetime.cloned() {
1349                                     let lt_def_id = cx.tcx.hir().local_def_id(param.hir_id);
1350                                     let cleaned = if !lt.is_elided() {
1351                                         lt.clean(cx)
1352                                     } else {
1353                                         self::types::Lifetime::elided()
1354                                     };
1355                                     lt_substs.insert(lt_def_id.to_def_id(), cleaned);
1356                                 }
1357                                 indices.lifetimes += 1;
1358                             }
1359                             hir::GenericParamKind::Type { ref default, .. } => {
1360                                 let ty_param_def_id = cx.tcx.hir().local_def_id(param.hir_id);
1361                                 let mut j = 0;
1362                                 let type_ = generic_args.args.iter().find_map(|arg| match arg {
1363                                     hir::GenericArg::Type(ty) => {
1364                                         if indices.types == j {
1365                                             return Some(ty);
1366                                         }
1367                                         j += 1;
1368                                         None
1369                                     }
1370                                     _ => None,
1371                                 });
1372                                 if let Some(ty) = type_ {
1373                                     ty_substs.insert(ty_param_def_id.to_def_id(), ty.clean(cx));
1374                                 } else if let Some(default) = *default {
1375                                     ty_substs
1376                                         .insert(ty_param_def_id.to_def_id(), default.clean(cx));
1377                                 }
1378                                 indices.types += 1;
1379                             }
1380                             hir::GenericParamKind::Const { .. } => {
1381                                 let const_param_def_id = cx.tcx.hir().local_def_id(param.hir_id);
1382                                 let mut j = 0;
1383                                 let const_ = generic_args.args.iter().find_map(|arg| match arg {
1384                                     hir::GenericArg::Const(ct) => {
1385                                         if indices.consts == j {
1386                                             return Some(ct);
1387                                         }
1388                                         j += 1;
1389                                         None
1390                                     }
1391                                     _ => None,
1392                                 });
1393                                 if let Some(ct) = const_ {
1394                                     ct_substs.insert(const_param_def_id.to_def_id(), ct.clean(cx));
1395                                 }
1396                                 // FIXME(const_generics_defaults)
1397                                 indices.consts += 1;
1398                             }
1399                         }
1400                     }
1401                 }
1402                 return cx.enter_alias(ty_substs, lt_substs, ct_substs, || ty.clean(cx));
1403             }
1404             resolve_type(cx, path.clean(cx), hir_id)
1405         }
1406         hir::QPath::Resolved(Some(ref qself), ref p) => {
1407             // Try to normalize `<X as Y>::T` to a type
1408             let ty = hir_ty_to_ty(cx.tcx, hir_ty);
1409             if let Some(normalized_value) = normalize(cx, ty) {
1410                 return normalized_value.clean(cx);
1411             }
1412
1413             let segments = if p.is_global() { &p.segments[1..] } else { &p.segments };
1414             let trait_segments = &segments[..segments.len() - 1];
1415             let trait_path = self::Path {
1416                 global: p.is_global(),
1417                 res: Res::Def(
1418                     DefKind::Trait,
1419                     cx.tcx.associated_item(p.res.def_id()).container.id(),
1420                 ),
1421                 segments: trait_segments.clean(cx),
1422             };
1423             Type::QPath {
1424                 name: p.segments.last().expect("segments were empty").ident.name,
1425                 self_type: box qself.clean(cx),
1426                 trait_: box resolve_type(cx, trait_path, hir_id),
1427             }
1428         }
1429         hir::QPath::TypeRelative(ref qself, ref segment) => {
1430             let ty = hir_ty_to_ty(cx.tcx, hir_ty);
1431             let res = if let ty::Projection(proj) = ty.kind() {
1432                 Res::Def(DefKind::Trait, proj.trait_ref(cx.tcx).def_id)
1433             } else {
1434                 Res::Err
1435             };
1436             let trait_path = hir::Path { span, res, segments: &[] };
1437             Type::QPath {
1438                 name: segment.ident.name,
1439                 self_type: box qself.clean(cx),
1440                 trait_: box resolve_type(cx, trait_path.clean(cx), hir_id),
1441             }
1442         }
1443         hir::QPath::LangItem(..) => bug!("clean: requiring documentation of lang item"),
1444     }
1445 }
1446
1447 impl Clean<Type> for hir::Ty<'_> {
1448     fn clean(&self, cx: &DocContext<'_>) -> Type {
1449         use rustc_hir::*;
1450
1451         match self.kind {
1452             TyKind::Never => Never,
1453             TyKind::Ptr(ref m) => RawPointer(m.mutbl, box m.ty.clean(cx)),
1454             TyKind::Rptr(ref l, ref m) => {
1455                 // There are two times a `Fresh` lifetime can be created:
1456                 // 1. For `&'_ x`, written by the user. This corresponds to `lower_lifetime` in `rustc_ast_lowering`.
1457                 // 2. For `&x` as a parameter to an `async fn`. This corresponds to `elided_ref_lifetime in `rustc_ast_lowering`.
1458                 //    See #59286 for more information.
1459                 // Ideally we would only hide the `'_` for case 2., but I don't know a way to distinguish it.
1460                 // Turning `fn f(&'_ self)` into `fn f(&self)` isn't the worst thing in the world, though;
1461                 // there's no case where it could cause the function to fail to compile.
1462                 let elided =
1463                     l.is_elided() || matches!(l.name, LifetimeName::Param(ParamName::Fresh(_)));
1464                 let lifetime = if elided { None } else { Some(l.clean(cx)) };
1465                 BorrowedRef { lifetime, mutability: m.mutbl, type_: box m.ty.clean(cx) }
1466             }
1467             TyKind::Slice(ref ty) => Slice(box ty.clean(cx)),
1468             TyKind::Array(ref ty, ref length) => {
1469                 let def_id = cx.tcx.hir().local_def_id(length.hir_id);
1470                 // NOTE(min_const_generics): We can't use `const_eval_poly` for constants
1471                 // as we currently do not supply the parent generics to anonymous constants
1472                 // but do allow `ConstKind::Param`.
1473                 //
1474                 // `const_eval_poly` tries to to first substitute generic parameters which
1475                 // results in an ICE while manually constructing the constant and using `eval`
1476                 // does nothing for `ConstKind::Param`.
1477                 let ct = ty::Const::from_anon_const(cx.tcx, def_id);
1478                 let param_env = cx.tcx.param_env(def_id);
1479                 let length = print_const(cx, ct.eval(cx.tcx, param_env));
1480                 Array(box ty.clean(cx), length)
1481             }
1482             TyKind::Tup(ref tys) => Tuple(tys.clean(cx)),
1483             TyKind::OpaqueDef(item_id, _) => {
1484                 let item = cx.tcx.hir().expect_item(item_id.id);
1485                 if let hir::ItemKind::OpaqueTy(ref ty) = item.kind {
1486                     ImplTrait(ty.bounds.clean(cx))
1487                 } else {
1488                     unreachable!()
1489                 }
1490             }
1491             TyKind::Path(_) => clean_qpath(&self, cx),
1492             TyKind::TraitObject(ref bounds, ref lifetime) => {
1493                 match bounds[0].clean(cx).trait_ {
1494                     ResolvedPath { path, param_names: None, did, is_generic } => {
1495                         let mut bounds: Vec<self::GenericBound> = bounds[1..]
1496                             .iter()
1497                             .map(|bound| {
1498                                 self::GenericBound::TraitBound(
1499                                     bound.clean(cx),
1500                                     hir::TraitBoundModifier::None,
1501                                 )
1502                             })
1503                             .collect();
1504                         if !lifetime.is_elided() {
1505                             bounds.push(self::GenericBound::Outlives(lifetime.clean(cx)));
1506                         }
1507                         ResolvedPath { path, param_names: Some(bounds), did, is_generic }
1508                     }
1509                     _ => Infer, // shouldn't happen
1510                 }
1511             }
1512             TyKind::BareFn(ref barefn) => BareFunction(box barefn.clean(cx)),
1513             TyKind::Infer | TyKind::Err => Infer,
1514             TyKind::Typeof(..) => panic!("unimplemented type {:?}", self.kind),
1515         }
1516     }
1517 }
1518
1519 /// Returns `None` if the type could not be normalized
1520 fn normalize(cx: &DocContext<'tcx>, ty: Ty<'_>) -> Option<Ty<'tcx>> {
1521     // HACK: low-churn fix for #79459 while we wait for a trait normalization fix
1522     if !cx.tcx.sess.opts.debugging_opts.normalize_docs {
1523         return None;
1524     }
1525
1526     use crate::rustc_trait_selection::infer::TyCtxtInferExt;
1527     use crate::rustc_trait_selection::traits::query::normalize::AtExt;
1528     use rustc_middle::traits::ObligationCause;
1529
1530     // Try to normalize `<X as Y>::T` to a type
1531     let lifted = ty.lift_to_tcx(cx.tcx).unwrap();
1532     let normalized = cx.tcx.infer_ctxt().enter(|infcx| {
1533         infcx
1534             .at(&ObligationCause::dummy(), cx.param_env.get())
1535             .normalize(lifted)
1536             .map(|resolved| infcx.resolve_vars_if_possible(resolved.value))
1537     });
1538     match normalized {
1539         Ok(normalized_value) => {
1540             debug!("normalized {:?} to {:?}", ty, normalized_value);
1541             Some(normalized_value)
1542         }
1543         Err(err) => {
1544             debug!("failed to normalize {:?}: {:?}", ty, err);
1545             None
1546         }
1547     }
1548 }
1549
1550 impl<'tcx> Clean<Type> for Ty<'tcx> {
1551     fn clean(&self, cx: &DocContext<'_>) -> Type {
1552         debug!("cleaning type: {:?}", self);
1553         let ty = normalize(cx, self).unwrap_or(self);
1554         match *ty.kind() {
1555             ty::Never => Never,
1556             ty::Bool => Primitive(PrimitiveType::Bool),
1557             ty::Char => Primitive(PrimitiveType::Char),
1558             ty::Int(int_ty) => Primitive(int_ty.into()),
1559             ty::Uint(uint_ty) => Primitive(uint_ty.into()),
1560             ty::Float(float_ty) => Primitive(float_ty.into()),
1561             ty::Str => Primitive(PrimitiveType::Str),
1562             ty::Slice(ty) => Slice(box ty.clean(cx)),
1563             ty::Array(ty, n) => {
1564                 let mut n = cx.tcx.lift(n).expect("array lift failed");
1565                 n = n.eval(cx.tcx, ty::ParamEnv::reveal_all());
1566                 let n = print_const(cx, n);
1567                 Array(box ty.clean(cx), n)
1568             }
1569             ty::RawPtr(mt) => RawPointer(mt.mutbl, box mt.ty.clean(cx)),
1570             ty::Ref(r, ty, mutbl) => {
1571                 BorrowedRef { lifetime: r.clean(cx), mutability: mutbl, type_: box ty.clean(cx) }
1572             }
1573             ty::FnDef(..) | ty::FnPtr(_) => {
1574                 let ty = cx.tcx.lift(*self).expect("FnPtr lift failed");
1575                 let sig = ty.fn_sig(cx.tcx);
1576                 let def_id = DefId::local(CRATE_DEF_INDEX);
1577                 BareFunction(box BareFunctionDecl {
1578                     unsafety: sig.unsafety(),
1579                     generic_params: Vec::new(),
1580                     decl: (def_id, sig).clean(cx),
1581                     abi: sig.abi(),
1582                 })
1583             }
1584             ty::Adt(def, substs) => {
1585                 let did = def.did;
1586                 let kind = match def.adt_kind() {
1587                     AdtKind::Struct => TypeKind::Struct,
1588                     AdtKind::Union => TypeKind::Union,
1589                     AdtKind::Enum => TypeKind::Enum,
1590                 };
1591                 inline::record_extern_fqn(cx, did, kind);
1592                 let path = external_path(cx, cx.tcx.item_name(did), None, false, vec![], substs);
1593                 ResolvedPath { path, param_names: None, did, is_generic: false }
1594             }
1595             ty::Foreign(did) => {
1596                 inline::record_extern_fqn(cx, did, TypeKind::Foreign);
1597                 let path = external_path(
1598                     cx,
1599                     cx.tcx.item_name(did),
1600                     None,
1601                     false,
1602                     vec![],
1603                     InternalSubsts::empty(),
1604                 );
1605                 ResolvedPath { path, param_names: None, did, is_generic: false }
1606             }
1607             ty::Dynamic(ref obj, ref reg) => {
1608                 // HACK: pick the first `did` as the `did` of the trait object. Someone
1609                 // might want to implement "native" support for marker-trait-only
1610                 // trait objects.
1611                 let mut dids = obj.principal_def_id().into_iter().chain(obj.auto_traits());
1612                 let did = dids
1613                     .next()
1614                     .unwrap_or_else(|| panic!("found trait object `{:?}` with no traits?", self));
1615                 let substs = match obj.principal() {
1616                     Some(principal) => principal.skip_binder().substs,
1617                     // marker traits have no substs.
1618                     _ => cx.tcx.intern_substs(&[]),
1619                 };
1620
1621                 inline::record_extern_fqn(cx, did, TypeKind::Trait);
1622
1623                 let mut param_names = vec![];
1624                 if let Some(b) = reg.clean(cx) {
1625                     param_names.push(GenericBound::Outlives(b));
1626                 }
1627                 for did in dids {
1628                     let empty = cx.tcx.intern_substs(&[]);
1629                     let path =
1630                         external_path(cx, cx.tcx.item_name(did), Some(did), false, vec![], empty);
1631                     inline::record_extern_fqn(cx, did, TypeKind::Trait);
1632                     let bound = GenericBound::TraitBound(
1633                         PolyTrait {
1634                             trait_: ResolvedPath {
1635                                 path,
1636                                 param_names: None,
1637                                 did,
1638                                 is_generic: false,
1639                             },
1640                             generic_params: Vec::new(),
1641                         },
1642                         hir::TraitBoundModifier::None,
1643                     );
1644                     param_names.push(bound);
1645                 }
1646
1647                 let mut bindings = vec![];
1648                 for pb in obj.projection_bounds() {
1649                     bindings.push(TypeBinding {
1650                         name: cx.tcx.associated_item(pb.item_def_id()).ident.name,
1651                         kind: TypeBindingKind::Equality { ty: pb.skip_binder().ty.clean(cx) },
1652                     });
1653                 }
1654
1655                 let path =
1656                     external_path(cx, cx.tcx.item_name(did), Some(did), false, bindings, substs);
1657                 ResolvedPath { path, param_names: Some(param_names), did, is_generic: false }
1658             }
1659             ty::Tuple(ref t) => {
1660                 Tuple(t.iter().map(|t| t.expect_ty()).collect::<Vec<_>>().clean(cx))
1661             }
1662
1663             ty::Projection(ref data) => data.clean(cx),
1664
1665             ty::Param(ref p) => {
1666                 if let Some(bounds) = cx.impl_trait_bounds.borrow_mut().remove(&p.index.into()) {
1667                     ImplTrait(bounds)
1668                 } else {
1669                     Generic(p.name)
1670                 }
1671             }
1672
1673             ty::Opaque(def_id, substs) => {
1674                 // Grab the "TraitA + TraitB" from `impl TraitA + TraitB`,
1675                 // by looking up the bounds associated with the def_id.
1676                 let substs = cx.tcx.lift(substs).expect("Opaque lift failed");
1677                 let bounds = cx
1678                     .tcx
1679                     .explicit_item_bounds(def_id)
1680                     .iter()
1681                     .map(|(bound, _)| bound.subst(cx.tcx, substs))
1682                     .collect::<Vec<_>>();
1683                 let mut regions = vec![];
1684                 let mut has_sized = false;
1685                 let mut bounds = bounds
1686                     .iter()
1687                     .filter_map(|bound| {
1688                         // Note: The substs of opaque types can contain unbound variables,
1689                         // meaning that we have to use `ignore_quantifiers_with_unbound_vars` here.
1690                         let bound_predicate = bound.bound_atom_with_opt_escaping(cx.tcx);
1691                         let trait_ref = match bound_predicate.skip_binder() {
1692                             ty::PredicateAtom::Trait(tr, _constness) => {
1693                                 bound_predicate.rebind(tr.trait_ref)
1694                             }
1695                             ty::PredicateAtom::TypeOutlives(ty::OutlivesPredicate(_ty, reg)) => {
1696                                 if let Some(r) = reg.clean(cx) {
1697                                     regions.push(GenericBound::Outlives(r));
1698                                 }
1699                                 return None;
1700                             }
1701                             _ => return None,
1702                         };
1703
1704                         if let Some(sized) = cx.tcx.lang_items().sized_trait() {
1705                             if trait_ref.def_id() == sized {
1706                                 has_sized = true;
1707                                 return None;
1708                             }
1709                         }
1710
1711                         let bounds: Vec<_> = bounds
1712                             .iter()
1713                             .filter_map(|bound| {
1714                                 if let ty::PredicateAtom::Projection(proj) =
1715                                     bound.bound_atom_with_opt_escaping(cx.tcx).skip_binder()
1716                                 {
1717                                     if proj.projection_ty.trait_ref(cx.tcx)
1718                                         == trait_ref.skip_binder()
1719                                     {
1720                                         Some(TypeBinding {
1721                                             name: cx
1722                                                 .tcx
1723                                                 .associated_item(proj.projection_ty.item_def_id)
1724                                                 .ident
1725                                                 .name,
1726                                             kind: TypeBindingKind::Equality {
1727                                                 ty: proj.ty.clean(cx),
1728                                             },
1729                                         })
1730                                     } else {
1731                                         None
1732                                     }
1733                                 } else {
1734                                     None
1735                                 }
1736                             })
1737                             .collect();
1738
1739                         Some((trait_ref, &bounds[..]).clean(cx))
1740                     })
1741                     .collect::<Vec<_>>();
1742                 bounds.extend(regions);
1743                 if !has_sized && !bounds.is_empty() {
1744                     bounds.insert(0, GenericBound::maybe_sized(cx));
1745                 }
1746                 ImplTrait(bounds)
1747             }
1748
1749             ty::Closure(..) | ty::Generator(..) => Tuple(vec![]), // FIXME(pcwalton)
1750
1751             ty::Bound(..) => panic!("Bound"),
1752             ty::Placeholder(..) => panic!("Placeholder"),
1753             ty::GeneratorWitness(..) => panic!("GeneratorWitness"),
1754             ty::Infer(..) => panic!("Infer"),
1755             ty::Error(_) => panic!("Error"),
1756         }
1757     }
1758 }
1759
1760 impl<'tcx> Clean<Constant> for ty::Const<'tcx> {
1761     fn clean(&self, cx: &DocContext<'_>) -> Constant {
1762         Constant {
1763             type_: self.ty.clean(cx),
1764             expr: format!("{}", self),
1765             value: None,
1766             is_literal: false,
1767         }
1768     }
1769 }
1770
1771 impl Clean<Item> for hir::StructField<'_> {
1772     fn clean(&self, cx: &DocContext<'_>) -> Item {
1773         let what_rustc_thinks = Item::from_hir_id_and_parts(
1774             self.hir_id,
1775             Some(self.ident.name),
1776             StructFieldItem(self.ty.clean(cx)),
1777             cx,
1778         );
1779         // Don't show `pub` for fields on enum variants; they are always public
1780         Item { visibility: self.vis.clean(cx), ..what_rustc_thinks }
1781     }
1782 }
1783
1784 impl Clean<Item> for ty::FieldDef {
1785     fn clean(&self, cx: &DocContext<'_>) -> Item {
1786         let what_rustc_thinks = Item::from_def_id_and_parts(
1787             self.did,
1788             Some(self.ident.name),
1789             StructFieldItem(cx.tcx.type_of(self.did).clean(cx)),
1790             cx,
1791         );
1792         // Don't show `pub` for fields on enum variants; they are always public
1793         Item { visibility: self.vis.clean(cx), ..what_rustc_thinks }
1794     }
1795 }
1796
1797 impl Clean<Visibility> for hir::Visibility<'_> {
1798     fn clean(&self, cx: &DocContext<'_>) -> Visibility {
1799         match self.node {
1800             hir::VisibilityKind::Public => Visibility::Public,
1801             hir::VisibilityKind::Inherited => Visibility::Inherited,
1802             hir::VisibilityKind::Crate(_) => {
1803                 let krate = DefId::local(CRATE_DEF_INDEX);
1804                 Visibility::Restricted(krate)
1805             }
1806             hir::VisibilityKind::Restricted { ref path, .. } => {
1807                 let path = path.clean(cx);
1808                 let did = register_res(cx, path.res);
1809                 Visibility::Restricted(did)
1810             }
1811         }
1812     }
1813 }
1814
1815 impl Clean<Visibility> for ty::Visibility {
1816     fn clean(&self, _cx: &DocContext<'_>) -> Visibility {
1817         match *self {
1818             ty::Visibility::Public => Visibility::Public,
1819             // NOTE: this is not quite right: `ty` uses `Invisible` to mean 'private',
1820             // while rustdoc really does mean inherited. That means that for enum variants, such as
1821             // `pub enum E { V }`, `V` will be marked as `Public` by `ty`, but as `Inherited` by rustdoc.
1822             // This is the main reason `impl Clean for hir::Visibility` still exists; various parts of clean
1823             // override `tcx.visibility` explicitly to make sure this distinction is captured.
1824             ty::Visibility::Invisible => Visibility::Inherited,
1825             ty::Visibility::Restricted(module) => Visibility::Restricted(module),
1826         }
1827     }
1828 }
1829
1830 impl Clean<VariantStruct> for rustc_hir::VariantData<'_> {
1831     fn clean(&self, cx: &DocContext<'_>) -> VariantStruct {
1832         VariantStruct {
1833             struct_type: doctree::struct_type_from_def(self),
1834             fields: self.fields().iter().map(|x| x.clean(cx)).collect(),
1835             fields_stripped: false,
1836         }
1837     }
1838 }
1839
1840 impl Clean<Item> for doctree::Variant<'_> {
1841     fn clean(&self, cx: &DocContext<'_>) -> Item {
1842         let what_rustc_thinks = Item::from_hir_id_and_parts(
1843             self.id,
1844             Some(self.name),
1845             VariantItem(Variant { kind: self.def.clean(cx) }),
1846             cx,
1847         );
1848         // don't show `pub` for variants, which are always public
1849         Item { visibility: Inherited, ..what_rustc_thinks }
1850     }
1851 }
1852
1853 impl Clean<Item> for ty::VariantDef {
1854     fn clean(&self, cx: &DocContext<'_>) -> Item {
1855         let kind = match self.ctor_kind {
1856             CtorKind::Const => VariantKind::CLike,
1857             CtorKind::Fn => VariantKind::Tuple(
1858                 self.fields.iter().map(|f| cx.tcx.type_of(f.did).clean(cx)).collect(),
1859             ),
1860             CtorKind::Fictive => VariantKind::Struct(VariantStruct {
1861                 struct_type: doctree::Plain,
1862                 fields_stripped: false,
1863                 fields: self
1864                     .fields
1865                     .iter()
1866                     .map(|field| {
1867                         let name = Some(field.ident.name);
1868                         let kind = StructFieldItem(cx.tcx.type_of(field.did).clean(cx));
1869                         let what_rustc_thinks =
1870                             Item::from_def_id_and_parts(field.did, name, kind, cx);
1871                         // don't show `pub` for fields, which are always public
1872                         Item { visibility: Visibility::Inherited, ..what_rustc_thinks }
1873                     })
1874                     .collect(),
1875             }),
1876         };
1877         let what_rustc_thinks = Item::from_def_id_and_parts(
1878             self.def_id,
1879             Some(self.ident.name),
1880             VariantItem(Variant { kind }),
1881             cx,
1882         );
1883         // don't show `pub` for fields, which are always public
1884         Item { visibility: Inherited, ..what_rustc_thinks }
1885     }
1886 }
1887
1888 impl Clean<VariantKind> for hir::VariantData<'_> {
1889     fn clean(&self, cx: &DocContext<'_>) -> VariantKind {
1890         match self {
1891             hir::VariantData::Struct(..) => VariantKind::Struct(self.clean(cx)),
1892             hir::VariantData::Tuple(..) => {
1893                 VariantKind::Tuple(self.fields().iter().map(|x| x.ty.clean(cx)).collect())
1894             }
1895             hir::VariantData::Unit(..) => VariantKind::CLike,
1896         }
1897     }
1898 }
1899
1900 impl Clean<Span> for rustc_span::Span {
1901     fn clean(&self, _cx: &DocContext<'_>) -> Span {
1902         Span::from_rustc_span(*self)
1903     }
1904 }
1905
1906 impl Clean<Path> for hir::Path<'_> {
1907     fn clean(&self, cx: &DocContext<'_>) -> Path {
1908         Path {
1909             global: self.is_global(),
1910             res: self.res,
1911             segments: if self.is_global() { &self.segments[1..] } else { &self.segments }.clean(cx),
1912         }
1913     }
1914 }
1915
1916 impl Clean<GenericArgs> for hir::GenericArgs<'_> {
1917     fn clean(&self, cx: &DocContext<'_>) -> GenericArgs {
1918         if self.parenthesized {
1919             let output = self.bindings[0].ty().clean(cx);
1920             GenericArgs::Parenthesized {
1921                 inputs: self.inputs().clean(cx),
1922                 output: if output != Type::Tuple(Vec::new()) { Some(output) } else { None },
1923             }
1924         } else {
1925             GenericArgs::AngleBracketed {
1926                 args: self
1927                     .args
1928                     .iter()
1929                     .map(|arg| match arg {
1930                         hir::GenericArg::Lifetime(lt) if !lt.is_elided() => {
1931                             GenericArg::Lifetime(lt.clean(cx))
1932                         }
1933                         hir::GenericArg::Lifetime(_) => GenericArg::Lifetime(Lifetime::elided()),
1934                         hir::GenericArg::Type(ty) => GenericArg::Type(ty.clean(cx)),
1935                         hir::GenericArg::Const(ct) => GenericArg::Const(ct.clean(cx)),
1936                     })
1937                     .collect(),
1938                 bindings: self.bindings.clean(cx),
1939             }
1940         }
1941     }
1942 }
1943
1944 impl Clean<PathSegment> for hir::PathSegment<'_> {
1945     fn clean(&self, cx: &DocContext<'_>) -> PathSegment {
1946         PathSegment { name: self.ident.name, args: self.generic_args().clean(cx) }
1947     }
1948 }
1949
1950 impl Clean<String> for Ident {
1951     #[inline]
1952     fn clean(&self, cx: &DocContext<'_>) -> String {
1953         self.name.clean(cx)
1954     }
1955 }
1956
1957 impl Clean<String> for Symbol {
1958     #[inline]
1959     fn clean(&self, _: &DocContext<'_>) -> String {
1960         self.to_string()
1961     }
1962 }
1963
1964 impl Clean<BareFunctionDecl> for hir::BareFnTy<'_> {
1965     fn clean(&self, cx: &DocContext<'_>) -> BareFunctionDecl {
1966         let (generic_params, decl) = enter_impl_trait(cx, || {
1967             (self.generic_params.clean(cx), (&*self.decl, &self.param_names[..]).clean(cx))
1968         });
1969         BareFunctionDecl { unsafety: self.unsafety, abi: self.abi, decl, generic_params }
1970     }
1971 }
1972
1973 impl Clean<Vec<Item>> for (&hir::Item<'_>, Option<Symbol>) {
1974     fn clean(&self, cx: &DocContext<'_>) -> Vec<Item> {
1975         use hir::ItemKind;
1976
1977         let (item, renamed) = self;
1978         let def_id = cx.tcx.hir().local_def_id(item.hir_id).to_def_id();
1979         let mut name = renamed.unwrap_or_else(|| cx.tcx.hir().name(item.hir_id));
1980         cx.with_param_env(def_id, || {
1981             let kind = match item.kind {
1982                 ItemKind::Static(ty, mutability, body_id) => StaticItem(Static {
1983                     type_: ty.clean(cx),
1984                     mutability,
1985                     expr: print_const_expr(cx, body_id),
1986                 }),
1987                 ItemKind::Const(ty, body_id) => ConstantItem(Constant {
1988                     type_: ty.clean(cx),
1989                     expr: print_const_expr(cx, body_id),
1990                     value: print_evaluated_const(cx, def_id),
1991                     is_literal: is_literal_expr(cx, body_id.hir_id),
1992                 }),
1993                 ItemKind::OpaqueTy(ref ty) => OpaqueTyItem(OpaqueTy {
1994                     bounds: ty.bounds.clean(cx),
1995                     generics: ty.generics.clean(cx),
1996                 }),
1997                 ItemKind::TyAlias(hir_ty, ref generics) => {
1998                     let rustdoc_ty = hir_ty.clean(cx);
1999                     let ty = hir_ty_to_ty(cx.tcx, hir_ty).clean(cx);
2000                     TypedefItem(
2001                         Typedef {
2002                             type_: rustdoc_ty,
2003                             generics: generics.clean(cx),
2004                             item_type: Some(ty),
2005                         },
2006                         false,
2007                     )
2008                 }
2009                 ItemKind::Enum(ref def, ref generics) => EnumItem(Enum {
2010                     variants: def.variants.iter().map(|v| v.clean(cx)).collect(),
2011                     generics: generics.clean(cx),
2012                     variants_stripped: false,
2013                 }),
2014                 ItemKind::TraitAlias(ref generics, bounds) => TraitAliasItem(TraitAlias {
2015                     generics: generics.clean(cx),
2016                     bounds: bounds.clean(cx),
2017                 }),
2018                 ItemKind::Union(ref variant_data, ref generics) => UnionItem(Union {
2019                     struct_type: doctree::struct_type_from_def(&variant_data),
2020                     generics: generics.clean(cx),
2021                     fields: variant_data.fields().clean(cx),
2022                     fields_stripped: false,
2023                 }),
2024                 ItemKind::Struct(ref variant_data, ref generics) => StructItem(Struct {
2025                     struct_type: doctree::struct_type_from_def(&variant_data),
2026                     generics: generics.clean(cx),
2027                     fields: variant_data.fields().clean(cx),
2028                     fields_stripped: false,
2029                 }),
2030                 ItemKind::Impl { .. } => return clean_impl(item, cx),
2031                 // proc macros can have a name set by attributes
2032                 ItemKind::Fn(ref sig, ref generics, body_id) => {
2033                     clean_fn_or_proc_macro(item, sig, generics, body_id, &mut name, cx)
2034                 }
2035                 hir::ItemKind::Trait(is_auto, unsafety, ref generics, ref bounds, ref item_ids) => {
2036                     let items = item_ids
2037                         .iter()
2038                         .map(|ti| cx.tcx.hir().trait_item(ti.id).clean(cx))
2039                         .collect();
2040                     let attrs = item.attrs.clean(cx);
2041                     let is_spotlight = attrs.has_doc_flag(sym::spotlight);
2042                     TraitItem(Trait {
2043                         unsafety,
2044                         items,
2045                         generics: generics.clean(cx),
2046                         bounds: bounds.clean(cx),
2047                         is_spotlight,
2048                         is_auto: is_auto.clean(cx),
2049                     })
2050                 }
2051                 ItemKind::ExternCrate(orig_name) => {
2052                     return clean_extern_crate(item, name, orig_name, cx);
2053                 }
2054                 _ => unreachable!("not yet converted"),
2055             };
2056
2057             vec![Item::from_def_id_and_parts(def_id, Some(name), kind, cx)]
2058         })
2059     }
2060 }
2061
2062 impl Clean<Item> for hir::Variant<'_> {
2063     fn clean(&self, cx: &DocContext<'_>) -> Item {
2064         let kind = VariantItem(Variant { kind: self.data.clean(cx) });
2065         let what_rustc_thinks =
2066             Item::from_hir_id_and_parts(self.id, Some(self.ident.name), kind, cx);
2067         // don't show `pub` for variants, which are always public
2068         Item { visibility: Inherited, ..what_rustc_thinks }
2069     }
2070 }
2071
2072 impl Clean<bool> for ty::ImplPolarity {
2073     /// Returns whether the impl has negative polarity.
2074     fn clean(&self, _: &DocContext<'_>) -> bool {
2075         match self {
2076             &ty::ImplPolarity::Positive |
2077             // FIXME: do we want to do something else here?
2078             &ty::ImplPolarity::Reservation => false,
2079             &ty::ImplPolarity::Negative => true,
2080         }
2081     }
2082 }
2083
2084 fn clean_impl(impl_: &hir::Item<'_>, cx: &DocContext<'_>) -> Vec<Item> {
2085     let mut ret = Vec::new();
2086     let (trait_, items, for_, unsafety, generics) = match &impl_.kind {
2087         hir::ItemKind::Impl { of_trait, items, self_ty, unsafety, generics, .. } => {
2088             (of_trait, items, self_ty, *unsafety, generics)
2089         }
2090         _ => unreachable!(),
2091     };
2092     let trait_ = trait_.clean(cx);
2093     let items = items.iter().map(|ii| cx.tcx.hir().impl_item(ii.id).clean(cx)).collect::<Vec<_>>();
2094     let def_id = cx.tcx.hir().local_def_id(impl_.hir_id);
2095
2096     // If this impl block is an implementation of the Deref trait, then we
2097     // need to try inlining the target's inherent impl blocks as well.
2098     if trait_.def_id() == cx.tcx.lang_items().deref_trait() {
2099         build_deref_target_impls(cx, &items, &mut ret);
2100     }
2101
2102     let provided: FxHashSet<Symbol> = trait_
2103         .def_id()
2104         .map(|did| cx.tcx.provided_trait_methods(did).map(|meth| meth.ident.name).collect())
2105         .unwrap_or_default();
2106
2107     let for_ = for_.clean(cx);
2108     let type_alias = for_.def_id().and_then(|did| match cx.tcx.def_kind(did) {
2109         DefKind::TyAlias => Some(cx.tcx.type_of(did).clean(cx)),
2110         _ => None,
2111     });
2112     let make_item = |trait_: Option<Type>, for_: Type, items: Vec<Item>| {
2113         let kind = ImplItem(Impl {
2114             unsafety,
2115             generics: generics.clean(cx),
2116             provided_trait_methods: provided.clone(),
2117             trait_,
2118             for_,
2119             items,
2120             negative_polarity: cx.tcx.impl_polarity(def_id).clean(cx),
2121             synthetic: false,
2122             blanket_impl: None,
2123         });
2124         Item::from_hir_id_and_parts(impl_.hir_id, None, kind, cx)
2125     };
2126     if let Some(type_alias) = type_alias {
2127         ret.push(make_item(trait_.clone(), type_alias, items.clone()));
2128     }
2129     ret.push(make_item(trait_, for_, items));
2130     ret
2131 }
2132
2133 fn clean_extern_crate(
2134     krate: &hir::Item<'_>,
2135     name: Symbol,
2136     orig_name: Option<Symbol>,
2137     cx: &DocContext<'_>,
2138 ) -> Vec<Item> {
2139     // this is the ID of the `extern crate` statement
2140     let def_id = cx.tcx.hir().local_def_id(krate.hir_id);
2141     let cnum = cx.tcx.extern_mod_stmt_cnum(def_id).unwrap_or(LOCAL_CRATE);
2142     // this is the ID of the crate itself
2143     let crate_def_id = DefId { krate: cnum, index: CRATE_DEF_INDEX };
2144     let please_inline = krate.vis.node.is_pub()
2145         && krate.attrs.iter().any(|a| {
2146             a.has_name(sym::doc)
2147                 && match a.meta_item_list() {
2148                     Some(l) => attr::list_contains_name(&l, sym::inline),
2149                     None => false,
2150                 }
2151         });
2152
2153     if please_inline {
2154         let mut visited = FxHashSet::default();
2155
2156         let res = Res::Def(DefKind::Mod, crate_def_id);
2157
2158         if let Some(items) = inline::try_inline(
2159             cx,
2160             cx.tcx.parent_module(krate.hir_id).to_def_id(),
2161             res,
2162             name,
2163             Some(krate.attrs),
2164             &mut visited,
2165         ) {
2166             return items;
2167         }
2168     }
2169     // FIXME: using `from_def_id_and_kind` breaks `rustdoc/masked` for some reason
2170     vec![Item {
2171         name: None,
2172         attrs: krate.attrs.clean(cx),
2173         source: krate.span.clean(cx),
2174         def_id: crate_def_id,
2175         visibility: krate.vis.clean(cx),
2176         kind: box ExternCrateItem(name, orig_name),
2177     }]
2178 }
2179
2180 impl Clean<Vec<Item>> for doctree::Import<'_> {
2181     fn clean(&self, cx: &DocContext<'_>) -> Vec<Item> {
2182         // We need this comparison because some imports (for std types for example)
2183         // are "inserted" as well but directly by the compiler and they should not be
2184         // taken into account.
2185         if self.span.ctxt().outer_expn_data().kind == ExpnKind::AstPass(AstPass::StdImports) {
2186             return Vec::new();
2187         }
2188
2189         let (doc_meta_item, please_inline) = self.attrs.lists(sym::doc).get_word_attr(sym::inline);
2190         let pub_underscore = self.vis.node.is_pub() && self.name == kw::Underscore;
2191
2192         if pub_underscore && please_inline {
2193             rustc_errors::struct_span_err!(
2194                 cx.tcx.sess,
2195                 doc_meta_item.unwrap().span(),
2196                 E0780,
2197                 "anonymous imports cannot be inlined"
2198             )
2199             .span_label(self.span, "anonymous import")
2200             .emit();
2201         }
2202
2203         // We consider inlining the documentation of `pub use` statements, but we
2204         // forcefully don't inline if this is not public or if the
2205         // #[doc(no_inline)] attribute is present.
2206         // Don't inline doc(hidden) imports so they can be stripped at a later stage.
2207         let mut denied = !self.vis.node.is_pub()
2208             || pub_underscore
2209             || self.attrs.iter().any(|a| {
2210                 a.has_name(sym::doc)
2211                     && match a.meta_item_list() {
2212                         Some(l) => {
2213                             attr::list_contains_name(&l, sym::no_inline)
2214                                 || attr::list_contains_name(&l, sym::hidden)
2215                         }
2216                         None => false,
2217                     }
2218             });
2219         // Also check whether imports were asked to be inlined, in case we're trying to re-export a
2220         // crate in Rust 2018+
2221         let path = self.path.clean(cx);
2222         let inner = if self.glob {
2223             if !denied {
2224                 let mut visited = FxHashSet::default();
2225                 if let Some(items) = inline::try_inline_glob(cx, path.res, &mut visited) {
2226                     return items;
2227                 }
2228             }
2229             Import::new_glob(resolve_use_source(cx, path), true)
2230         } else {
2231             let name = self.name;
2232             if !please_inline {
2233                 if let Res::Def(DefKind::Mod, did) = path.res {
2234                     if !did.is_local() && did.index == CRATE_DEF_INDEX {
2235                         // if we're `pub use`ing an extern crate root, don't inline it unless we
2236                         // were specifically asked for it
2237                         denied = true;
2238                     }
2239                 }
2240             }
2241             if !denied {
2242                 let mut visited = FxHashSet::default();
2243
2244                 if let Some(mut items) = inline::try_inline(
2245                     cx,
2246                     cx.tcx.parent_module(self.id).to_def_id(),
2247                     path.res,
2248                     name,
2249                     Some(self.attrs),
2250                     &mut visited,
2251                 ) {
2252                     items.push(Item {
2253                         name: None,
2254                         attrs: self.attrs.clean(cx),
2255                         source: self.span.clean(cx),
2256                         def_id: cx.tcx.hir().local_def_id(self.id).to_def_id(),
2257                         visibility: self.vis.clean(cx),
2258                         kind: box ImportItem(Import::new_simple(
2259                             self.name,
2260                             resolve_use_source(cx, path),
2261                             false,
2262                         )),
2263                     });
2264                     return items;
2265                 }
2266             }
2267             Import::new_simple(name, resolve_use_source(cx, path), true)
2268         };
2269
2270         vec![Item {
2271             name: None,
2272             attrs: self.attrs.clean(cx),
2273             source: self.span.clean(cx),
2274             def_id: cx.tcx.hir().local_def_id(self.id).to_def_id(),
2275             visibility: self.vis.clean(cx),
2276             kind: box ImportItem(inner),
2277         }]
2278     }
2279 }
2280
2281 impl Clean<Item> for (&hir::ForeignItem<'_>, Option<Symbol>) {
2282     fn clean(&self, cx: &DocContext<'_>) -> Item {
2283         let (item, renamed) = self;
2284         cx.with_param_env(cx.tcx.hir().local_def_id(item.hir_id).to_def_id(), || {
2285             let kind = match item.kind {
2286                 hir::ForeignItemKind::Fn(ref decl, ref names, ref generics) => {
2287                     let abi = cx.tcx.hir().get_foreign_abi(item.hir_id);
2288                     let (generics, decl) = enter_impl_trait(cx, || {
2289                         (generics.clean(cx), (&**decl, &names[..]).clean(cx))
2290                     });
2291                     let (all_types, ret_types) = get_all_types(&generics, &decl, cx);
2292                     ForeignFunctionItem(Function {
2293                         decl,
2294                         generics,
2295                         header: hir::FnHeader {
2296                             unsafety: hir::Unsafety::Unsafe,
2297                             abi,
2298                             constness: hir::Constness::NotConst,
2299                             asyncness: hir::IsAsync::NotAsync,
2300                         },
2301                         all_types,
2302                         ret_types,
2303                     })
2304                 }
2305                 hir::ForeignItemKind::Static(ref ty, mutability) => ForeignStaticItem(Static {
2306                     type_: ty.clean(cx),
2307                     mutability,
2308                     expr: String::new(),
2309                 }),
2310                 hir::ForeignItemKind::Type => ForeignTypeItem,
2311             };
2312
2313             Item::from_hir_id_and_parts(
2314                 item.hir_id,
2315                 Some(renamed.unwrap_or(item.ident.name)),
2316                 kind,
2317                 cx,
2318             )
2319         })
2320     }
2321 }
2322
2323 impl Clean<Item> for (&hir::MacroDef<'_>, Option<Symbol>) {
2324     fn clean(&self, cx: &DocContext<'_>) -> Item {
2325         let (item, renamed) = self;
2326         let name = renamed.unwrap_or(item.ident.name);
2327         let tts = item.ast.body.inner_tokens().trees().collect::<Vec<_>>();
2328         // Extract the spans of all matchers. They represent the "interface" of the macro.
2329         let matchers = tts.chunks(4).map(|arm| arm[0].span()).collect::<Vec<_>>();
2330         let source = if item.ast.macro_rules {
2331             format!(
2332                 "macro_rules! {} {{\n{}}}",
2333                 name,
2334                 matchers
2335                     .iter()
2336                     .map(|span| { format!("    {} => {{ ... }};\n", span.to_src(cx)) })
2337                     .collect::<String>(),
2338             )
2339         } else {
2340             let vis = item.vis.clean(cx);
2341             let def_id = cx.tcx.hir().local_def_id(item.hir_id).to_def_id();
2342
2343             if matchers.len() <= 1 {
2344                 format!(
2345                     "{}macro {}{} {{\n    ...\n}}",
2346                     vis.print_with_space(cx.tcx, def_id),
2347                     name,
2348                     matchers.iter().map(|span| span.to_src(cx)).collect::<String>(),
2349                 )
2350             } else {
2351                 format!(
2352                     "{}macro {} {{\n{}}}",
2353                     vis.print_with_space(cx.tcx, def_id),
2354                     name,
2355                     matchers
2356                         .iter()
2357                         .map(|span| { format!("    {} => {{ ... }},\n", span.to_src(cx)) })
2358                         .collect::<String>(),
2359                 )
2360             }
2361         };
2362
2363         Item::from_hir_id_and_parts(
2364             item.hir_id,
2365             Some(name),
2366             MacroItem(Macro { source, imported_from: None }),
2367             cx,
2368         )
2369     }
2370 }
2371
2372 impl Clean<TypeBinding> for hir::TypeBinding<'_> {
2373     fn clean(&self, cx: &DocContext<'_>) -> TypeBinding {
2374         TypeBinding { name: self.ident.name, kind: self.kind.clean(cx) }
2375     }
2376 }
2377
2378 impl Clean<TypeBindingKind> for hir::TypeBindingKind<'_> {
2379     fn clean(&self, cx: &DocContext<'_>) -> TypeBindingKind {
2380         match *self {
2381             hir::TypeBindingKind::Equality { ref ty } => {
2382                 TypeBindingKind::Equality { ty: ty.clean(cx) }
2383             }
2384             hir::TypeBindingKind::Constraint { ref bounds } => {
2385                 TypeBindingKind::Constraint { bounds: bounds.iter().map(|b| b.clean(cx)).collect() }
2386             }
2387         }
2388     }
2389 }
2390
2391 enum SimpleBound {
2392     TraitBound(Vec<PathSegment>, Vec<SimpleBound>, Vec<GenericParamDef>, hir::TraitBoundModifier),
2393     Outlives(Lifetime),
2394 }
2395
2396 impl From<GenericBound> for SimpleBound {
2397     fn from(bound: GenericBound) -> Self {
2398         match bound.clone() {
2399             GenericBound::Outlives(l) => SimpleBound::Outlives(l),
2400             GenericBound::TraitBound(t, mod_) => match t.trait_ {
2401                 Type::ResolvedPath { path, param_names, .. } => SimpleBound::TraitBound(
2402                     path.segments,
2403                     param_names.map_or_else(Vec::new, |v| {
2404                         v.iter().map(|p| SimpleBound::from(p.clone())).collect()
2405                     }),
2406                     t.generic_params,
2407                     mod_,
2408                 ),
2409                 _ => panic!("Unexpected bound {:?}", bound),
2410             },
2411         }
2412     }
2413 }