compiler/rustc_middle/src/ty/structural_impls.rs

   1 //! This module contains implements of the `Lift` and `TypeFoldable`
   2 //! traits for various types in the Rust compiler. Most are written by
   3 //! hand, though we've recently added some macros and proc-macros to help with the tedium.
   4
   5 use crate::mir::interpret;
   6 use crate::mir::{Field, ProjectionKind};
   7 use crate::ty::fold::{FallibleTypeFolder, TypeFoldable, TypeSuperFoldable};
   8 use crate::ty::print::{with_no_trimmed_paths, FmtPrinter, Printer};
   9 use crate::ty::visit::{TypeSuperVisitable, TypeVisitable, TypeVisitor};
  10 use crate::ty::{self, InferConst, Lift, Term, TermKind, Ty, TyCtxt};
  11 use rustc_data_structures::functor::IdFunctor;
  12 use rustc_hir::def::Namespace;
  13 use rustc_index::vec::{Idx, IndexVec};
  14
  15 use std::fmt;
  16 use std::mem::ManuallyDrop;
  17 use std::ops::ControlFlow;
  18 use std::rc::Rc;
  19 use std::sync::Arc;
  20
  21 impl fmt::Debug for ty::TraitDef {
  22     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  23         ty::tls::with(|tcx| {
  24             with_no_trimmed_paths!({
  25                 f.write_str(
  26                     &FmtPrinter::new(tcx, Namespace::TypeNS)
  27                         .print_def_path(self.def_id, &[])?
  28                         .into_buffer(),
  29                 )
  30             })
  31         })
  32     }
  33 }
  34
  35 impl<'tcx> fmt::Debug for ty::AdtDef<'tcx> {
  36     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  37         ty::tls::with(|tcx| {
  38             with_no_trimmed_paths!({
  39                 f.write_str(
  40                     &FmtPrinter::new(tcx, Namespace::TypeNS)
  41                         .print_def_path(self.did(), &[])?
  42                         .into_buffer(),
  43                 )
  44             })
  45         })
  46     }
  47 }
  48
  49 impl fmt::Debug for ty::UpvarId {
  50     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  51         let name = ty::tls::with(|tcx| tcx.hir().name(self.var_path.hir_id));
  52         write!(f, "UpvarId({:?};`{}`;{:?})", self.var_path.hir_id, name, self.closure_expr_id)
  53     }
  54 }
  55
  56 impl<'tcx> fmt::Debug for ty::ExistentialTraitRef<'tcx> {
  57     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  58         with_no_trimmed_paths!(fmt::Display::fmt(self, f))
  59     }
  60 }
  61
  62 impl<'tcx> fmt::Debug for ty::adjustment::Adjustment<'tcx> {
  63     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  64         write!(f, "{:?} -> {}", self.kind, self.target)
  65     }
  66 }
  67
  68 impl fmt::Debug for ty::BoundRegionKind {
  69     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  70         match *self {
  71             ty::BrAnon(n, span) => write!(f, "BrAnon({n:?}, {span:?})"),
  72             ty::BrNamed(did, name) => {
  73                 if did.is_crate_root() {
  74                     write!(f, "BrNamed({})", name)
  75                 } else {
  76                     write!(f, "BrNamed({:?}, {})", did, name)
  77                 }
  78             }
  79             ty::BrEnv => write!(f, "BrEnv"),
  80         }
  81     }
  82 }
  83
  84 impl fmt::Debug for ty::FreeRegion {
  85     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  86         write!(f, "ReFree({:?}, {:?})", self.scope, self.bound_region)
  87     }
  88 }
  89
  90 impl<'tcx> fmt::Debug for ty::FnSig<'tcx> {
  91     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  92         write!(f, "({:?}; c_variadic: {})->{:?}", self.inputs(), self.c_variadic, self.output())
  93     }
  94 }
  95
  96 impl<'tcx> fmt::Debug for ty::ConstVid<'tcx> {
  97     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  98         write!(f, "_#{}c", self.index)
  99     }
 100 }
 101
 102 impl<'tcx> fmt::Debug for ty::TraitRef<'tcx> {
 103     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 104         with_no_trimmed_paths!(fmt::Display::fmt(self, f))
 105     }
 106 }
 107
 108 impl<'tcx> fmt::Debug for Ty<'tcx> {
 109     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 110         with_no_trimmed_paths!(fmt::Display::fmt(self, f))
 111     }
 112 }
 113
 114 impl fmt::Debug for ty::ParamTy {
 115     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 116         write!(f, "{}/#{}", self.name, self.index)
 117     }
 118 }
 119
 120 impl fmt::Debug for ty::ParamConst {
 121     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 122         write!(f, "{}/#{}", self.name, self.index)
 123     }
 124 }
 125
 126 impl<'tcx> fmt::Debug for ty::TraitPredicate<'tcx> {
 127     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 128         if let ty::BoundConstness::ConstIfConst = self.constness {
 129             write!(f, "~const ")?;
 130         }
 131         write!(f, "TraitPredicate({:?}, polarity:{:?})", self.trait_ref, self.polarity)
 132     }
 133 }
 134
 135 impl<'tcx> fmt::Debug for ty::ProjectionPredicate<'tcx> {
 136     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 137         write!(f, "ProjectionPredicate({:?}, {:?})", self.projection_ty, self.term)
 138     }
 139 }
 140
 141 impl<'tcx> fmt::Debug for ty::Predicate<'tcx> {
 142     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 143         write!(f, "{:?}", self.kind())
 144     }
 145 }
 146
 147 impl<'tcx> fmt::Debug for ty::Clause<'tcx> {
 148     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 149         match *self {
 150             ty::Clause::Trait(ref a) => a.fmt(f),
 151             ty::Clause::RegionOutlives(ref pair) => pair.fmt(f),
 152             ty::Clause::TypeOutlives(ref pair) => pair.fmt(f),
 153             ty::Clause::Projection(ref pair) => pair.fmt(f),
 154         }
 155     }
 156 }
 157
 158 impl<'tcx> fmt::Debug for ty::PredicateKind<'tcx> {
 159     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 160         match *self {
 161             ty::PredicateKind::Clause(ref a) => a.fmt(f),
 162             ty::PredicateKind::Subtype(ref pair) => pair.fmt(f),
 163             ty::PredicateKind::Coerce(ref pair) => pair.fmt(f),
 164             ty::PredicateKind::WellFormed(data) => write!(f, "WellFormed({:?})", data),
 165             ty::PredicateKind::ObjectSafe(trait_def_id) => {
 166                 write!(f, "ObjectSafe({:?})", trait_def_id)
 167             }
 168             ty::PredicateKind::ClosureKind(closure_def_id, closure_substs, kind) => {
 169                 write!(f, "ClosureKind({:?}, {:?}, {:?})", closure_def_id, closure_substs, kind)
 170             }
 171             ty::PredicateKind::ConstEvaluatable(ct) => {
 172                 write!(f, "ConstEvaluatable({ct:?})")
 173             }
 174             ty::PredicateKind::ConstEquate(c1, c2) => write!(f, "ConstEquate({:?}, {:?})", c1, c2),
 175             ty::PredicateKind::TypeWellFormedFromEnv(ty) => {
 176                 write!(f, "TypeWellFormedFromEnv({:?})", ty)
 177             }
 178             ty::PredicateKind::Ambiguous => write!(f, "Ambiguous"),
 179         }
 180     }
 181 }
 182
 183 ///////////////////////////////////////////////////////////////////////////
 184 // Atomic structs
 185 //
 186 // For things that don't carry any arena-allocated data (and are
 187 // copy...), just add them to this list.
 188
 189 TrivialTypeTraversalAndLiftImpls! {
 190     (),
 191     bool,
 192     usize,
 193     ::rustc_target::abi::VariantIdx,
 194     u32,
 195     u64,
 196     String,
 197     crate::middle::region::Scope,
 198     crate::ty::FloatTy,
 199     ::rustc_ast::InlineAsmOptions,
 200     ::rustc_ast::InlineAsmTemplatePiece,
 201     ::rustc_ast::NodeId,
 202     ::rustc_span::symbol::Symbol,
 203     ::rustc_hir::def::Res,
 204     ::rustc_hir::def_id::DefId,
 205     ::rustc_hir::def_id::LocalDefId,
 206     ::rustc_hir::HirId,
 207     ::rustc_hir::MatchSource,
 208     ::rustc_hir::Mutability,
 209     ::rustc_hir::Unsafety,
 210     ::rustc_target::asm::InlineAsmRegOrRegClass,
 211     ::rustc_target::spec::abi::Abi,
 212     crate::mir::coverage::ExpressionOperandId,
 213     crate::mir::coverage::CounterValueReference,
 214     crate::mir::coverage::InjectedExpressionId,
 215     crate::mir::coverage::InjectedExpressionIndex,
 216     crate::mir::coverage::MappedExpressionIndex,
 217     crate::mir::Local,
 218     crate::mir::Promoted,
 219     crate::traits::Reveal,
 220     crate::ty::adjustment::AutoBorrowMutability,
 221     crate::ty::AdtKind,
 222     crate::ty::BoundConstness,
 223     // Including `BoundRegionKind` is a *bit* dubious, but direct
 224     // references to bound region appear in `ty::Error`, and aren't
 225     // really meant to be folded. In general, we can only fold a fully
 226     // general `Region`.
 227     crate::ty::BoundRegionKind,
 228     crate::ty::AssocItem,
 229     crate::ty::AssocKind,
 230     crate::ty::AliasKind,
 231     crate::ty::Placeholder<crate::ty::BoundRegionKind>,
 232     crate::ty::ClosureKind,
 233     crate::ty::FreeRegion,
 234     crate::ty::InferTy,
 235     crate::ty::IntVarValue,
 236     crate::ty::ParamConst,
 237     crate::ty::ParamTy,
 238     crate::ty::adjustment::PointerCast,
 239     crate::ty::RegionVid,
 240     crate::ty::UniverseIndex,
 241     crate::ty::Variance,
 242     ::rustc_span::Span,
 243     ::rustc_errors::ErrorGuaranteed,
 244     Field,
 245     interpret::Scalar,
 246     rustc_target::abi::Size,
 247     rustc_type_ir::DebruijnIndex,
 248     ty::BoundVar,
 249     ty::Placeholder<ty::BoundVar>,
 250 }
 251
 252 TrivialTypeTraversalAndLiftImpls! {
 253     for<'tcx> {
 254         ty::ValTree<'tcx>,
 255     }
 256 }
 257
 258 ///////////////////////////////////////////////////////////////////////////
 259 // Lift implementations
 260
 261 impl<'tcx, A: Lift<'tcx>, B: Lift<'tcx>> Lift<'tcx> for (A, B) {
 262     type Lifted = (A::Lifted, B::Lifted);
 263     fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
 264         Some((tcx.lift(self.0)?, tcx.lift(self.1)?))
 265     }
 266 }
 267
 268 impl<'tcx, A: Lift<'tcx>, B: Lift<'tcx>, C: Lift<'tcx>> Lift<'tcx> for (A, B, C) {
 269     type Lifted = (A::Lifted, B::Lifted, C::Lifted);
 270     fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
 271         Some((tcx.lift(self.0)?, tcx.lift(self.1)?, tcx.lift(self.2)?))
 272     }
 273 }
 274
 275 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for Option<T> {
 276     type Lifted = Option<T::Lifted>;
 277     fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
 278         Some(match self {
 279             Some(x) => Some(tcx.lift(x)?),
 280             None => None,
 281         })
 282     }
 283 }
 284
 285 impl<'tcx, T: Lift<'tcx>, E: Lift<'tcx>> Lift<'tcx> for Result<T, E> {
 286     type Lifted = Result<T::Lifted, E::Lifted>;
 287     fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
 288         match self {
 289             Ok(x) => tcx.lift(x).map(Ok),
 290             Err(e) => tcx.lift(e).map(Err),
 291         }
 292     }
 293 }
 294
 295 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for Box<T> {
 296     type Lifted = Box<T::Lifted>;
 297     fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
 298         Some(Box::new(tcx.lift(*self)?))
 299     }
 300 }
 301
 302 impl<'tcx, T: Lift<'tcx> + Clone> Lift<'tcx> for Rc<T> {
 303     type Lifted = Rc<T::Lifted>;
 304     fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
 305         Some(Rc::new(tcx.lift(self.as_ref().clone())?))
 306     }
 307 }
 308
 309 impl<'tcx, T: Lift<'tcx> + Clone> Lift<'tcx> for Arc<T> {
 310     type Lifted = Arc<T::Lifted>;
 311     fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
 312         Some(Arc::new(tcx.lift(self.as_ref().clone())?))
 313     }
 314 }
 315 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for Vec<T> {
 316     type Lifted = Vec<T::Lifted>;
 317     fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
 318         self.into_iter().map(|v| tcx.lift(v)).collect()
 319     }
 320 }
 321
 322 impl<'tcx, I: Idx, T: Lift<'tcx>> Lift<'tcx> for IndexVec<I, T> {
 323     type Lifted = IndexVec<I, T::Lifted>;
 324     fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
 325         self.into_iter().map(|e| tcx.lift(e)).collect()
 326     }
 327 }
 328
 329 impl<'a, 'tcx> Lift<'tcx> for Term<'a> {
 330     type Lifted = ty::Term<'tcx>;
 331     fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
 332         Some(
 333             match self.unpack() {
 334                 TermKind::Ty(ty) => TermKind::Ty(tcx.lift(ty)?),
 335                 TermKind::Const(c) => TermKind::Const(tcx.lift(c)?),
 336             }
 337             .pack(),
 338         )
 339     }
 340 }
 341 impl<'a, 'tcx> Lift<'tcx> for ty::ParamEnv<'a> {
 342     type Lifted = ty::ParamEnv<'tcx>;
 343     fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
 344         tcx.lift(self.caller_bounds())
 345             .map(|caller_bounds| ty::ParamEnv::new(caller_bounds, self.reveal(), self.constness()))
 346     }
 347 }
 348
 349 ///////////////////////////////////////////////////////////////////////////
 350 // TypeFoldable implementations.
 351
 352 /// AdtDefs are basically the same as a DefId.
 353 impl<'tcx> TypeFoldable<'tcx> for ty::AdtDef<'tcx> {
 354     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, _folder: &mut F) -> Result<Self, F::Error> {
 355         Ok(self)
 356     }
 357 }
 358
 359 impl<'tcx> TypeVisitable<'tcx> for ty::AdtDef<'tcx> {
 360     fn visit_with<V: TypeVisitor<'tcx>>(&self, _visitor: &mut V) -> ControlFlow<V::BreakTy> {
 361         ControlFlow::CONTINUE
 362     }
 363 }
 364
 365 impl<'tcx, T: TypeFoldable<'tcx>, U: TypeFoldable<'tcx>> TypeFoldable<'tcx> for (T, U) {
 366     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(
 367         self,
 368         folder: &mut F,
 369     ) -> Result<(T, U), F::Error> {
 370         Ok((self.0.try_fold_with(folder)?, self.1.try_fold_with(folder)?))
 371     }
 372 }
 373
 374 impl<'tcx, T: TypeVisitable<'tcx>, U: TypeVisitable<'tcx>> TypeVisitable<'tcx> for (T, U) {
 375     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
 376         self.0.visit_with(visitor)?;
 377         self.1.visit_with(visitor)
 378     }
 379 }
 380
 381 impl<'tcx, A: TypeFoldable<'tcx>, B: TypeFoldable<'tcx>, C: TypeFoldable<'tcx>> TypeFoldable<'tcx>
 382     for (A, B, C)
 383 {
 384     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(
 385         self,
 386         folder: &mut F,
 387     ) -> Result<(A, B, C), F::Error> {
 388         Ok((
 389             self.0.try_fold_with(folder)?,
 390             self.1.try_fold_with(folder)?,
 391             self.2.try_fold_with(folder)?,
 392         ))
 393     }
 394 }
 395
 396 impl<'tcx, A: TypeVisitable<'tcx>, B: TypeVisitable<'tcx>, C: TypeVisitable<'tcx>>
 397     TypeVisitable<'tcx> for (A, B, C)
 398 {
 399     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
 400         self.0.visit_with(visitor)?;
 401         self.1.visit_with(visitor)?;
 402         self.2.visit_with(visitor)
 403     }
 404 }
 405
 406 EnumTypeTraversalImpl! {
 407     impl<'tcx, T> TypeFoldable<'tcx> for Option<T> {
 408         (Some)(a),
 409         (None),
 410     } where T: TypeFoldable<'tcx>
 411 }
 412 EnumTypeTraversalImpl! {
 413     impl<'tcx, T> TypeVisitable<'tcx> for Option<T> {
 414         (Some)(a),
 415         (None),
 416     } where T: TypeVisitable<'tcx>
 417 }
 418
 419 EnumTypeTraversalImpl! {
 420     impl<'tcx, T, E> TypeFoldable<'tcx> for Result<T, E> {
 421         (Ok)(a),
 422         (Err)(a),
 423     } where T: TypeFoldable<'tcx>, E: TypeFoldable<'tcx>,
 424 }
 425 EnumTypeTraversalImpl! {
 426     impl<'tcx, T, E> TypeVisitable<'tcx> for Result<T, E> {
 427         (Ok)(a),
 428         (Err)(a),
 429     } where T: TypeVisitable<'tcx>, E: TypeVisitable<'tcx>,
 430 }
 431
 432 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Rc<T> {
 433     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(
 434         mut self,
 435         folder: &mut F,
 436     ) -> Result<Self, F::Error> {
 437         // We merely want to replace the contained `T`, if at all possible,
 438         // so that we don't needlessly allocate a new `Rc` or indeed clone
 439         // the contained type.
 440         unsafe {
 441             // First step is to ensure that we have a unique reference to
 442             // the contained type, which `Rc::make_mut` will accomplish (by
 443             // allocating a new `Rc` and cloning the `T` only if required).
 444             // This is done *before* casting to `Rc<ManuallyDrop<T>>` so that
 445             // panicking during `make_mut` does not leak the `T`.
 446             Rc::make_mut(&mut self);
 447
 448             // Casting to `Rc<ManuallyDrop<T>>` is safe because `ManuallyDrop`
 449             // is `repr(transparent)`.
 450             let ptr = Rc::into_raw(self).cast::<ManuallyDrop<T>>();
 451             let mut unique = Rc::from_raw(ptr);
 452
 453             // Call to `Rc::make_mut` above guarantees that `unique` is the
 454             // sole reference to the contained value, so we can avoid doing
 455             // a checked `get_mut` here.
 456             let slot = Rc::get_mut_unchecked(&mut unique);
 457
 458             // Semantically move the contained type out from `unique`, fold
 459             // it, then move the folded value back into `unique`.  Should
 460             // folding fail, `ManuallyDrop` ensures that the "moved-out"
 461             // value is not re-dropped.
 462             let owned = ManuallyDrop::take(slot);
 463             let folded = owned.try_fold_with(folder)?;
 464             *slot = ManuallyDrop::new(folded);
 465
 466             // Cast back to `Rc<T>`.
 467             Ok(Rc::from_raw(Rc::into_raw(unique).cast()))
 468         }
 469     }
 470 }
 471
 472 impl<'tcx, T: TypeVisitable<'tcx>> TypeVisitable<'tcx> for Rc<T> {
 473     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
 474         (**self).visit_with(visitor)
 475     }
 476 }
 477
 478 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Arc<T> {
 479     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(
 480         mut self,
 481         folder: &mut F,
 482     ) -> Result<Self, F::Error> {
 483         // We merely want to replace the contained `T`, if at all possible,
 484         // so that we don't needlessly allocate a new `Arc` or indeed clone
 485         // the contained type.
 486         unsafe {
 487             // First step is to ensure that we have a unique reference to
 488             // the contained type, which `Arc::make_mut` will accomplish (by
 489             // allocating a new `Arc` and cloning the `T` only if required).
 490             // This is done *before* casting to `Arc<ManuallyDrop<T>>` so that
 491             // panicking during `make_mut` does not leak the `T`.
 492             Arc::make_mut(&mut self);
 493
 494             // Casting to `Arc<ManuallyDrop<T>>` is safe because `ManuallyDrop`
 495             // is `repr(transparent)`.
 496             let ptr = Arc::into_raw(self).cast::<ManuallyDrop<T>>();
 497             let mut unique = Arc::from_raw(ptr);
 498
 499             // Call to `Arc::make_mut` above guarantees that `unique` is the
 500             // sole reference to the contained value, so we can avoid doing
 501             // a checked `get_mut` here.
 502             let slot = Arc::get_mut_unchecked(&mut unique);
 503
 504             // Semantically move the contained type out from `unique`, fold
 505             // it, then move the folded value back into `unique`.  Should
 506             // folding fail, `ManuallyDrop` ensures that the "moved-out"
 507             // value is not re-dropped.
 508             let owned = ManuallyDrop::take(slot);
 509             let folded = owned.try_fold_with(folder)?;
 510             *slot = ManuallyDrop::new(folded);
 511
 512             // Cast back to `Arc<T>`.
 513             Ok(Arc::from_raw(Arc::into_raw(unique).cast()))
 514         }
 515     }
 516 }
 517
 518 impl<'tcx, T: TypeVisitable<'tcx>> TypeVisitable<'tcx> for Arc<T> {
 519     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
 520         (**self).visit_with(visitor)
 521     }
 522 }
 523
 524 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Box<T> {
 525     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
 526         self.try_map_id(|value| value.try_fold_with(folder))
 527     }
 528 }
 529
 530 impl<'tcx, T: TypeVisitable<'tcx>> TypeVisitable<'tcx> for Box<T> {
 531     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
 532         (**self).visit_with(visitor)
 533     }
 534 }
 535
 536 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Vec<T> {
 537     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
 538         self.try_map_id(|t| t.try_fold_with(folder))
 539     }
 540 }
 541
 542 impl<'tcx, T: TypeVisitable<'tcx>> TypeVisitable<'tcx> for Vec<T> {
 543     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
 544         self.iter().try_for_each(|t| t.visit_with(visitor))
 545     }
 546 }
 547
 548 impl<'tcx, T: TypeVisitable<'tcx>> TypeVisitable<'tcx> for &[T] {
 549     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
 550         self.iter().try_for_each(|t| t.visit_with(visitor))
 551     }
 552 }
 553
 554 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Box<[T]> {
 555     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
 556         self.try_map_id(|t| t.try_fold_with(folder))
 557     }
 558 }
 559
 560 impl<'tcx, T: TypeVisitable<'tcx>> TypeVisitable<'tcx> for Box<[T]> {
 561     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
 562         self.iter().try_for_each(|t| t.visit_with(visitor))
 563     }
 564 }
 565
 566 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for ty::Binder<'tcx, T> {
 567     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
 568         folder.try_fold_binder(self)
 569     }
 570 }
 571
 572 impl<'tcx, T: TypeVisitable<'tcx>> TypeVisitable<'tcx> for ty::Binder<'tcx, T> {
 573     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
 574         visitor.visit_binder(self)
 575     }
 576 }
 577
 578 impl<'tcx, T: TypeFoldable<'tcx>> TypeSuperFoldable<'tcx> for ty::Binder<'tcx, T> {
 579     fn try_super_fold_with<F: FallibleTypeFolder<'tcx>>(
 580         self,
 581         folder: &mut F,
 582     ) -> Result<Self, F::Error> {
 583         self.try_map_bound(|ty| ty.try_fold_with(folder))
 584     }
 585 }
 586
 587 impl<'tcx, T: TypeVisitable<'tcx>> TypeSuperVisitable<'tcx> for ty::Binder<'tcx, T> {
 588     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
 589         self.as_ref().skip_binder().visit_with(visitor)
 590     }
 591 }
 592
 593 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>> {
 594     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
 595         ty::util::fold_list(self, folder, |tcx, v| tcx.intern_poly_existential_predicates(v))
 596     }
 597 }
 598
 599 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<ty::Const<'tcx>> {
 600     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
 601         ty::util::fold_list(self, folder, |tcx, v| tcx.mk_const_list(v.iter()))
 602     }
 603 }
 604
 605 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<ProjectionKind> {
 606     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
 607         ty::util::fold_list(self, folder, |tcx, v| tcx.intern_projs(v))
 608     }
 609 }
 610
 611 impl<'tcx> TypeFoldable<'tcx> for Ty<'tcx> {
 612     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
 613         folder.try_fold_ty(self)
 614     }
 615 }
 616
 617 impl<'tcx> TypeVisitable<'tcx> for Ty<'tcx> {
 618     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
 619         visitor.visit_ty(*self)
 620     }
 621 }
 622
 623 impl<'tcx> TypeSuperFoldable<'tcx> for Ty<'tcx> {
 624     fn try_super_fold_with<F: FallibleTypeFolder<'tcx>>(
 625         self,
 626         folder: &mut F,
 627     ) -> Result<Self, F::Error> {
 628         let kind = match *self.kind() {
 629             ty::RawPtr(tm) => ty::RawPtr(tm.try_fold_with(folder)?),
 630             ty::Array(typ, sz) => ty::Array(typ.try_fold_with(folder)?, sz.try_fold_with(folder)?),
 631             ty::Slice(typ) => ty::Slice(typ.try_fold_with(folder)?),
 632             ty::Adt(tid, substs) => ty::Adt(tid, substs.try_fold_with(folder)?),
 633             ty::Dynamic(trait_ty, region, representation) => ty::Dynamic(
 634                 trait_ty.try_fold_with(folder)?,
 635                 region.try_fold_with(folder)?,
 636                 representation,
 637             ),
 638             ty::Tuple(ts) => ty::Tuple(ts.try_fold_with(folder)?),
 639             ty::FnDef(def_id, substs) => ty::FnDef(def_id, substs.try_fold_with(folder)?),
 640             ty::FnPtr(f) => ty::FnPtr(f.try_fold_with(folder)?),
 641             ty::Ref(r, ty, mutbl) => {
 642                 ty::Ref(r.try_fold_with(folder)?, ty.try_fold_with(folder)?, mutbl)
 643             }
 644             ty::Generator(did, substs, movability) => {
 645                 ty::Generator(did, substs.try_fold_with(folder)?, movability)
 646             }
 647             ty::GeneratorWitness(types) => ty::GeneratorWitness(types.try_fold_with(folder)?),
 648             ty::Closure(did, substs) => ty::Closure(did, substs.try_fold_with(folder)?),
 649             ty::Alias(kind, data) => ty::Alias(kind, data.try_fold_with(folder)?),
 650
 651             ty::Bool
 652             | ty::Char
 653             | ty::Str
 654             | ty::Int(_)
 655             | ty::Uint(_)
 656             | ty::Float(_)
 657             | ty::Error(_)
 658             | ty::Infer(_)
 659             | ty::Param(..)
 660             | ty::Bound(..)
 661             | ty::Placeholder(..)
 662             | ty::Never
 663             | ty::Foreign(..) => return Ok(self),
 664         };
 665
 666         Ok(if *self.kind() == kind { self } else { folder.tcx().mk_ty(kind) })
 667     }
 668 }
 669
 670 impl<'tcx> TypeSuperVisitable<'tcx> for Ty<'tcx> {
 671     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
 672         match self.kind() {
 673             ty::RawPtr(ref tm) => tm.visit_with(visitor),
 674             ty::Array(typ, sz) => {
 675                 typ.visit_with(visitor)?;
 676                 sz.visit_with(visitor)
 677             }
 678             ty::Slice(typ) => typ.visit_with(visitor),
 679             ty::Adt(_, substs) => substs.visit_with(visitor),
 680             ty::Dynamic(ref trait_ty, ref reg, _) => {
 681                 trait_ty.visit_with(visitor)?;
 682                 reg.visit_with(visitor)
 683             }
 684             ty::Tuple(ts) => ts.visit_with(visitor),
 685             ty::FnDef(_, substs) => substs.visit_with(visitor),
 686             ty::FnPtr(ref f) => f.visit_with(visitor),
 687             ty::Ref(r, ty, _) => {
 688                 r.visit_with(visitor)?;
 689                 ty.visit_with(visitor)
 690             }
 691             ty::Generator(_did, ref substs, _) => substs.visit_with(visitor),
 692             ty::GeneratorWitness(ref types) => types.visit_with(visitor),
 693             ty::Closure(_did, ref substs) => substs.visit_with(visitor),
 694             ty::Alias(_, ref data) => data.visit_with(visitor),
 695
 696             ty::Bool
 697             | ty::Char
 698             | ty::Str
 699             | ty::Int(_)
 700             | ty::Uint(_)
 701             | ty::Float(_)
 702             | ty::Error(_)
 703             | ty::Infer(_)
 704             | ty::Bound(..)
 705             | ty::Placeholder(..)
 706             | ty::Param(..)
 707             | ty::Never
 708             | ty::Foreign(..) => ControlFlow::CONTINUE,
 709         }
 710     }
 711 }
 712
 713 impl<'tcx> TypeFoldable<'tcx> for ty::Region<'tcx> {
 714     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
 715         folder.try_fold_region(self)
 716     }
 717 }
 718
 719 impl<'tcx> TypeVisitable<'tcx> for ty::Region<'tcx> {
 720     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
 721         visitor.visit_region(*self)
 722     }
 723 }
 724
 725 impl<'tcx> TypeSuperFoldable<'tcx> for ty::Region<'tcx> {
 726     fn try_super_fold_with<F: FallibleTypeFolder<'tcx>>(
 727         self,
 728         _folder: &mut F,
 729     ) -> Result<Self, F::Error> {
 730         Ok(self)
 731     }
 732 }
 733
 734 impl<'tcx> TypeSuperVisitable<'tcx> for ty::Region<'tcx> {
 735     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _visitor: &mut V) -> ControlFlow<V::BreakTy> {
 736         ControlFlow::CONTINUE
 737     }
 738 }
 739
 740 impl<'tcx> TypeFoldable<'tcx> for ty::Predicate<'tcx> {
 741     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
 742         folder.try_fold_predicate(self)
 743     }
 744 }
 745
 746 impl<'tcx> TypeVisitable<'tcx> for ty::Predicate<'tcx> {
 747     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
 748         visitor.visit_predicate(*self)
 749     }
 750
 751     #[inline]
 752     fn has_vars_bound_at_or_above(&self, binder: ty::DebruijnIndex) -> bool {
 753         self.outer_exclusive_binder() > binder
 754     }
 755
 756     #[inline]
 757     fn has_type_flags(&self, flags: ty::TypeFlags) -> bool {
 758         self.flags().intersects(flags)
 759     }
 760 }
 761
 762 impl<'tcx> TypeSuperFoldable<'tcx> for ty::Predicate<'tcx> {
 763     fn try_super_fold_with<F: FallibleTypeFolder<'tcx>>(
 764         self,
 765         folder: &mut F,
 766     ) -> Result<Self, F::Error> {
 767         let new = self.kind().try_fold_with(folder)?;
 768         Ok(folder.tcx().reuse_or_mk_predicate(self, new))
 769     }
 770 }
 771
 772 impl<'tcx> TypeSuperVisitable<'tcx> for ty::Predicate<'tcx> {
 773     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
 774         self.kind().visit_with(visitor)
 775     }
 776 }
 777
 778 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<ty::Predicate<'tcx>> {
 779     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
 780         ty::util::fold_list(self, folder, |tcx, v| tcx.intern_predicates(v))
 781     }
 782 }
 783
 784 impl<'tcx, T: TypeFoldable<'tcx>, I: Idx> TypeFoldable<'tcx> for IndexVec<I, T> {
 785     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
 786         self.try_map_id(|x| x.try_fold_with(folder))
 787     }
 788 }
 789
 790 impl<'tcx, T: TypeVisitable<'tcx>, I: Idx> TypeVisitable<'tcx> for IndexVec<I, T> {
 791     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
 792         self.iter().try_for_each(|t| t.visit_with(visitor))
 793     }
 794 }
 795
 796 impl<'tcx> TypeFoldable<'tcx> for ty::Const<'tcx> {
 797     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
 798         folder.try_fold_const(self)
 799     }
 800 }
 801
 802 impl<'tcx> TypeVisitable<'tcx> for ty::Const<'tcx> {
 803     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
 804         visitor.visit_const(*self)
 805     }
 806 }
 807
 808 impl<'tcx> TypeSuperFoldable<'tcx> for ty::Const<'tcx> {
 809     fn try_super_fold_with<F: FallibleTypeFolder<'tcx>>(
 810         self,
 811         folder: &mut F,
 812     ) -> Result<Self, F::Error> {
 813         let ty = self.ty().try_fold_with(folder)?;
 814         let kind = self.kind().try_fold_with(folder)?;
 815         if ty != self.ty() || kind != self.kind() {
 816             Ok(folder.tcx().mk_const(kind, ty))
 817         } else {
 818             Ok(self)
 819         }
 820     }
 821 }
 822
 823 impl<'tcx> TypeSuperVisitable<'tcx> for ty::Const<'tcx> {
 824     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
 825         self.ty().visit_with(visitor)?;
 826         self.kind().visit_with(visitor)
 827     }
 828 }
 829
 830 impl<'tcx> TypeFoldable<'tcx> for InferConst<'tcx> {
 831     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, _folder: &mut F) -> Result<Self, F::Error> {
 832         Ok(self)
 833     }
 834 }
 835
 836 impl<'tcx> TypeVisitable<'tcx> for InferConst<'tcx> {
 837     fn visit_with<V: TypeVisitor<'tcx>>(&self, _visitor: &mut V) -> ControlFlow<V::BreakTy> {
 838         ControlFlow::CONTINUE
 839     }
 840 }
 841
 842 impl<'tcx> TypeSuperVisitable<'tcx> for ty::UnevaluatedConst<'tcx> {
 843     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
 844         self.substs.visit_with(visitor)
 845     }
 846 }