src/librustc/ty/structural_impls.rs

   1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use infer::type_variable;
  12 use ty::{self, Lift, Ty, TyCtxt};
  13 use ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
  14 use rustc_data_structures::accumulate_vec::AccumulateVec;
  15 use rustc_data_structures::indexed_vec::{IndexVec, Idx};
  16
  17 use std::rc::Rc;
  18 use syntax::abi;
  19
  20 use hir;
  21
  22 ///////////////////////////////////////////////////////////////////////////
  23 // Lift implementations
  24
  25 impl<'tcx, A: Lift<'tcx>, B: Lift<'tcx>> Lift<'tcx> for (A, B) {
  26     type Lifted = (A::Lifted, B::Lifted);
  27     fn lift_to_tcx<'a, 'gcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Self::Lifted> {
  28         tcx.lift(&self.0).and_then(|a| tcx.lift(&self.1).map(|b| (a, b)))
  29     }
  30 }
  31
  32 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for Option<T> {
  33     type Lifted = Option<T::Lifted>;
  34     fn lift_to_tcx<'a, 'gcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Self::Lifted> {
  35         match *self {
  36             Some(ref x) => tcx.lift(x).map(Some),
  37             None => Some(None)
  38         }
  39     }
  40 }
  41
  42 impl<'tcx, T: Lift<'tcx>, E: Lift<'tcx>> Lift<'tcx> for Result<T, E> {
  43     type Lifted = Result<T::Lifted, E::Lifted>;
  44     fn lift_to_tcx<'a, 'gcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Self::Lifted> {
  45         match *self {
  46             Ok(ref x) => tcx.lift(x).map(Ok),
  47             Err(ref e) => tcx.lift(e).map(Err)
  48         }
  49     }
  50 }
  51
  52 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for [T] {
  53     type Lifted = Vec<T::Lifted>;
  54     fn lift_to_tcx<'a, 'gcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Self::Lifted> {
  55         // type annotation needed to inform `projection_must_outlive`
  56         let mut result : Vec<<T as Lift<'tcx>>::Lifted>
  57             = Vec::with_capacity(self.len());
  58         for x in self {
  59             if let Some(value) = tcx.lift(x) {
  60                 result.push(value);
  61             } else {
  62                 return None;
  63             }
  64         }
  65         Some(result)
  66     }
  67 }
  68
  69 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for Vec<T> {
  70     type Lifted = Vec<T::Lifted>;
  71     fn lift_to_tcx<'a, 'gcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Self::Lifted> {
  72         tcx.lift(&self[..])
  73     }
  74 }
  75
  76 impl<'a, 'tcx> Lift<'tcx> for ty::TraitRef<'a> {
  77     type Lifted = ty::TraitRef<'tcx>;
  78     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
  79         tcx.lift(&self.substs).map(|substs| ty::TraitRef {
  80             def_id: self.def_id,
  81             substs: substs
  82         })
  83     }
  84 }
  85
  86 impl<'a, 'tcx> Lift<'tcx> for ty::ExistentialTraitRef<'a> {
  87     type Lifted = ty::ExistentialTraitRef<'tcx>;
  88     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
  89         tcx.lift(&self.substs).map(|substs| ty::ExistentialTraitRef {
  90             def_id: self.def_id,
  91             substs: substs
  92         })
  93     }
  94 }
  95
  96 impl<'a, 'tcx> Lift<'tcx> for ty::TraitPredicate<'a> {
  97     type Lifted = ty::TraitPredicate<'tcx>;
  98     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>)
  99                              -> Option<ty::TraitPredicate<'tcx>> {
 100         tcx.lift(&self.trait_ref).map(|trait_ref| ty::TraitPredicate {
 101             trait_ref: trait_ref
 102         })
 103     }
 104 }
 105
 106 impl<'a, 'tcx> Lift<'tcx> for ty::EquatePredicate<'a> {
 107     type Lifted = ty::EquatePredicate<'tcx>;
 108     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>)
 109                              -> Option<ty::EquatePredicate<'tcx>> {
 110         tcx.lift(&(self.0, self.1)).map(|(a, b)| ty::EquatePredicate(a, b))
 111     }
 112 }
 113
 114 impl<'a, 'tcx> Lift<'tcx> for ty::SubtypePredicate<'a> {
 115     type Lifted = ty::SubtypePredicate<'tcx>;
 116     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>)
 117                              -> Option<ty::SubtypePredicate<'tcx>> {
 118         tcx.lift(&(self.a, self.b)).map(|(a, b)| ty::SubtypePredicate {
 119             a_is_expected: self.a_is_expected,
 120             a: a,
 121             b: b,
 122         })
 123     }
 124 }
 125
 126 impl<'tcx, A: Copy+Lift<'tcx>, B: Copy+Lift<'tcx>> Lift<'tcx> for ty::OutlivesPredicate<A, B> {
 127     type Lifted = ty::OutlivesPredicate<A::Lifted, B::Lifted>;
 128     fn lift_to_tcx<'a, 'gcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 129         tcx.lift(&(self.0, self.1)).map(|(a, b)| ty::OutlivesPredicate(a, b))
 130     }
 131 }
 132
 133 impl<'a, 'tcx> Lift<'tcx> for ty::ProjectionTy<'a> {
 134     type Lifted = ty::ProjectionTy<'tcx>;
 135     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>)
 136                              -> Option<ty::ProjectionTy<'tcx>> {
 137         tcx.lift(&self.trait_ref).map(|trait_ref| {
 138             ty::ProjectionTy::from_ref_and_name(tcx, trait_ref, self.item_name(tcx))
 139         })
 140     }
 141 }
 142
 143 impl<'a, 'tcx> Lift<'tcx> for ty::ProjectionPredicate<'a> {
 144     type Lifted = ty::ProjectionPredicate<'tcx>;
 145     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>)
 146                              -> Option<ty::ProjectionPredicate<'tcx>> {
 147         tcx.lift(&(self.projection_ty, self.ty)).map(|(projection_ty, ty)| {
 148             ty::ProjectionPredicate {
 149                 projection_ty: projection_ty,
 150                 ty: ty
 151             }
 152         })
 153     }
 154 }
 155
 156 impl<'a, 'tcx> Lift<'tcx> for ty::ExistentialProjection<'a> {
 157     type Lifted = ty::ExistentialProjection<'tcx>;
 158     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 159         tcx.lift(&(self.trait_ref, self.ty)).map(|(trait_ref, ty)| {
 160             ty::ExistentialProjection {
 161                 trait_ref: trait_ref,
 162                 item_name: self.item_name,
 163                 ty: ty
 164             }
 165         })
 166     }
 167 }
 168
 169 impl<'a, 'tcx> Lift<'tcx> for ty::Predicate<'a> {
 170     type Lifted = ty::Predicate<'tcx>;
 171     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 172         match *self {
 173             ty::Predicate::Trait(ref binder) => {
 174                 tcx.lift(binder).map(ty::Predicate::Trait)
 175             }
 176             ty::Predicate::Equate(ref binder) => {
 177                 tcx.lift(binder).map(ty::Predicate::Equate)
 178             }
 179             ty::Predicate::Subtype(ref binder) => {
 180                 tcx.lift(binder).map(ty::Predicate::Subtype)
 181             }
 182             ty::Predicate::RegionOutlives(ref binder) => {
 183                 tcx.lift(binder).map(ty::Predicate::RegionOutlives)
 184             }
 185             ty::Predicate::TypeOutlives(ref binder) => {
 186                 tcx.lift(binder).map(ty::Predicate::TypeOutlives)
 187             }
 188             ty::Predicate::Projection(ref binder) => {
 189                 tcx.lift(binder).map(ty::Predicate::Projection)
 190             }
 191             ty::Predicate::WellFormed(ty) => {
 192                 tcx.lift(&ty).map(ty::Predicate::WellFormed)
 193             }
 194             ty::Predicate::ClosureKind(closure_def_id, kind) => {
 195                 Some(ty::Predicate::ClosureKind(closure_def_id, kind))
 196             }
 197             ty::Predicate::ObjectSafe(trait_def_id) => {
 198                 Some(ty::Predicate::ObjectSafe(trait_def_id))
 199             }
 200         }
 201     }
 202 }
 203
 204 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for ty::Binder<T> {
 205     type Lifted = ty::Binder<T::Lifted>;
 206     fn lift_to_tcx<'a, 'gcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 207         tcx.lift(&self.0).map(|x| ty::Binder(x))
 208     }
 209 }
 210
 211 impl<'a, 'tcx> Lift<'tcx> for ty::ClosureSubsts<'a> {
 212     type Lifted = ty::ClosureSubsts<'tcx>;
 213     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 214         tcx.lift(&self.substs).map(|substs| {
 215             ty::ClosureSubsts { substs: substs }
 216         })
 217     }
 218 }
 219
 220 impl<'a, 'tcx> Lift<'tcx> for ty::ItemSubsts<'a> {
 221     type Lifted = ty::ItemSubsts<'tcx>;
 222     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 223         tcx.lift(&self.substs).map(|substs| {
 224             ty::ItemSubsts {
 225                 substs: substs
 226             }
 227         })
 228     }
 229 }
 230
 231 impl<'a, 'tcx> Lift<'tcx> for ty::adjustment::AutoBorrow<'a> {
 232     type Lifted = ty::adjustment::AutoBorrow<'tcx>;
 233     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 234         match *self {
 235             ty::adjustment::AutoBorrow::Ref(r, m) => {
 236                 tcx.lift(&r).map(|r| ty::adjustment::AutoBorrow::Ref(r, m))
 237             }
 238             ty::adjustment::AutoBorrow::RawPtr(m) => {
 239                 Some(ty::adjustment::AutoBorrow::RawPtr(m))
 240             }
 241         }
 242     }
 243 }
 244
 245 impl<'a, 'tcx> Lift<'tcx> for ty::FnSig<'a> {
 246     type Lifted = ty::FnSig<'tcx>;
 247     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 248         tcx.lift(&self.inputs_and_output).map(|x| {
 249             ty::FnSig {
 250                 inputs_and_output: x,
 251                 variadic: self.variadic,
 252                 unsafety: self.unsafety,
 253                 abi: self.abi,
 254             }
 255         })
 256     }
 257 }
 258
 259 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for ty::error::ExpectedFound<T> {
 260     type Lifted = ty::error::ExpectedFound<T::Lifted>;
 261     fn lift_to_tcx<'a, 'gcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 262         tcx.lift(&self.expected).and_then(|expected| {
 263             tcx.lift(&self.found).map(|found| {
 264                 ty::error::ExpectedFound {
 265                     expected: expected,
 266                     found: found
 267                 }
 268             })
 269         })
 270     }
 271 }
 272
 273 impl<'a, 'tcx> Lift<'tcx> for type_variable::Default<'a> {
 274     type Lifted = type_variable::Default<'tcx>;
 275     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 276         tcx.lift(&self.ty).map(|ty| {
 277             type_variable::Default {
 278                 ty: ty,
 279                 origin_span: self.origin_span,
 280                 def_id: self.def_id
 281             }
 282         })
 283     }
 284 }
 285
 286 impl<'a, 'tcx> Lift<'tcx> for ty::error::TypeError<'a> {
 287     type Lifted = ty::error::TypeError<'tcx>;
 288     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 289         use ty::error::TypeError::*;
 290
 291         Some(match *self {
 292             Mismatch => Mismatch,
 293             UnsafetyMismatch(x) => UnsafetyMismatch(x),
 294             AbiMismatch(x) => AbiMismatch(x),
 295             Mutability => Mutability,
 296             TupleSize(x) => TupleSize(x),
 297             FixedArraySize(x) => FixedArraySize(x),
 298             ArgCount => ArgCount,
 299             RegionsDoesNotOutlive(a, b) => {
 300                 return tcx.lift(&(a, b)).map(|(a, b)| RegionsDoesNotOutlive(a, b))
 301             }
 302             RegionsNotSame(a, b) => {
 303                 return tcx.lift(&(a, b)).map(|(a, b)| RegionsNotSame(a, b))
 304             }
 305             RegionsNoOverlap(a, b) => {
 306                 return tcx.lift(&(a, b)).map(|(a, b)| RegionsNoOverlap(a, b))
 307             }
 308             RegionsInsufficientlyPolymorphic(a, b, ref c) => {
 309                 let c = c.clone();
 310                 return tcx.lift(&b).map(|b| RegionsInsufficientlyPolymorphic(a, b, c))
 311             }
 312             RegionsOverlyPolymorphic(a, b, ref c) => {
 313                 let c = c.clone();
 314                 return tcx.lift(&b).map(|b| RegionsOverlyPolymorphic(a, b, c))
 315             }
 316             IntMismatch(x) => IntMismatch(x),
 317             FloatMismatch(x) => FloatMismatch(x),
 318             Traits(x) => Traits(x),
 319             VariadicMismatch(x) => VariadicMismatch(x),
 320             CyclicTy => CyclicTy,
 321             ProjectionNameMismatched(x) => ProjectionNameMismatched(x),
 322             ProjectionBoundsLength(x) => ProjectionBoundsLength(x),
 323
 324             Sorts(ref x) => return tcx.lift(x).map(Sorts),
 325             TyParamDefaultMismatch(ref x) => {
 326                 return tcx.lift(x).map(TyParamDefaultMismatch)
 327             }
 328             ExistentialMismatch(ref x) => return tcx.lift(x).map(ExistentialMismatch)
 329         })
 330     }
 331 }
 332
 333 ///////////////////////////////////////////////////////////////////////////
 334 // TypeFoldable implementations.
 335 //
 336 // Ideally, each type should invoke `folder.fold_foo(self)` and
 337 // nothing else. In some cases, though, we haven't gotten around to
 338 // adding methods on the `folder` yet, and thus the folding is
 339 // hard-coded here. This is less-flexible, because folders cannot
 340 // override the behavior, but there are a lot of random types and one
 341 // can easily refactor the folding into the TypeFolder trait as
 342 // needed.
 343
 344 macro_rules! CopyImpls {
 345     ($($ty:ty),+) => {
 346         $(
 347             impl<'tcx> TypeFoldable<'tcx> for $ty {
 348                 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, _: &mut F) -> $ty {
 349                     *self
 350                 }
 351
 352                 fn super_visit_with<F: TypeVisitor<'tcx>>(&self, _: &mut F) -> bool {
 353                     false
 354                 }
 355             }
 356         )+
 357     }
 358 }
 359
 360 CopyImpls! { (), hir::Unsafety, abi::Abi }
 361
 362 impl<'tcx, T:TypeFoldable<'tcx>, U:TypeFoldable<'tcx>> TypeFoldable<'tcx> for (T, U) {
 363     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> (T, U) {
 364         (self.0.fold_with(folder), self.1.fold_with(folder))
 365     }
 366
 367     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 368         self.0.visit_with(visitor) || self.1.visit_with(visitor)
 369     }
 370 }
 371
 372 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Option<T> {
 373     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 374         self.as_ref().map(|t| t.fold_with(folder))
 375     }
 376
 377     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 378         self.iter().any(|t| t.visit_with(visitor))
 379     }
 380 }
 381
 382 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Rc<T> {
 383     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 384         Rc::new((**self).fold_with(folder))
 385     }
 386
 387     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 388         (**self).visit_with(visitor)
 389     }
 390 }
 391
 392 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Box<T> {
 393     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 394         let content: T = (**self).fold_with(folder);
 395         box content
 396     }
 397
 398     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 399         (**self).visit_with(visitor)
 400     }
 401 }
 402
 403 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Vec<T> {
 404     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 405         self.iter().map(|t| t.fold_with(folder)).collect()
 406     }
 407
 408     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 409         self.iter().any(|t| t.visit_with(visitor))
 410     }
 411 }
 412
 413 impl<'tcx, T:TypeFoldable<'tcx>> TypeFoldable<'tcx> for ty::Binder<T> {
 414     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 415         ty::Binder(self.0.fold_with(folder))
 416     }
 417
 418     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 419         folder.fold_binder(self)
 420     }
 421
 422     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 423         self.0.visit_with(visitor)
 424     }
 425
 426     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 427         visitor.visit_binder(self)
 428     }
 429 }
 430
 431 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::Slice<ty::ExistentialPredicate<'tcx>> {
 432     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 433         let v = self.iter().map(|p| p.fold_with(folder)).collect::<AccumulateVec<[_; 8]>>();
 434         folder.tcx().intern_existential_predicates(&v)
 435     }
 436
 437     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 438         self.iter().any(|p| p.visit_with(visitor))
 439     }
 440 }
 441
 442 impl<'tcx> TypeFoldable<'tcx> for ty::ExistentialPredicate<'tcx> {
 443     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self  {
 444         use ty::ExistentialPredicate::*;
 445         match *self {
 446             Trait(ref tr) => Trait(tr.fold_with(folder)),
 447             Projection(ref p) => Projection(p.fold_with(folder)),
 448             AutoTrait(did) => AutoTrait(did),
 449         }
 450     }
 451
 452     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 453         match *self {
 454             ty::ExistentialPredicate::Trait(ref tr) => tr.visit_with(visitor),
 455             ty::ExistentialPredicate::Projection(ref p) => p.visit_with(visitor),
 456             ty::ExistentialPredicate::AutoTrait(_) => false,
 457         }
 458     }
 459 }
 460
 461 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::Slice<Ty<'tcx>> {
 462     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 463         let v = self.iter().map(|t| t.fold_with(folder)).collect::<AccumulateVec<[_; 8]>>();
 464         folder.tcx().intern_type_list(&v)
 465     }
 466
 467     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 468         self.iter().any(|t| t.visit_with(visitor))
 469     }
 470 }
 471
 472 impl<'tcx> TypeFoldable<'tcx> for Ty<'tcx> {
 473     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 474         let sty = match self.sty {
 475             ty::TyRawPtr(tm) => ty::TyRawPtr(tm.fold_with(folder)),
 476             ty::TyArray(typ, sz) => ty::TyArray(typ.fold_with(folder), sz),
 477             ty::TySlice(typ) => ty::TySlice(typ.fold_with(folder)),
 478             ty::TyAdt(tid, substs) => ty::TyAdt(tid, substs.fold_with(folder)),
 479             ty::TyDynamic(ref trait_ty, ref region) =>
 480                 ty::TyDynamic(trait_ty.fold_with(folder), region.fold_with(folder)),
 481             ty::TyTuple(ts, defaulted) => ty::TyTuple(ts.fold_with(folder), defaulted),
 482             ty::TyFnDef(def_id, substs, f) => {
 483                 ty::TyFnDef(def_id,
 484                             substs.fold_with(folder),
 485                             f.fold_with(folder))
 486             }
 487             ty::TyFnPtr(f) => ty::TyFnPtr(f.fold_with(folder)),
 488             ty::TyRef(ref r, tm) => {
 489                 ty::TyRef(r.fold_with(folder), tm.fold_with(folder))
 490             }
 491             ty::TyClosure(did, substs) => ty::TyClosure(did, substs.fold_with(folder)),
 492             ty::TyProjection(ref data) => ty::TyProjection(data.fold_with(folder)),
 493             ty::TyAnon(did, substs) => ty::TyAnon(did, substs.fold_with(folder)),
 494             ty::TyBool | ty::TyChar | ty::TyStr | ty::TyInt(_) |
 495             ty::TyUint(_) | ty::TyFloat(_) | ty::TyError | ty::TyInfer(_) |
 496             ty::TyParam(..) | ty::TyNever => return self
 497         };
 498
 499         if self.sty == sty {
 500             self
 501         } else {
 502             folder.tcx().mk_ty(sty)
 503         }
 504     }
 505
 506     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 507         folder.fold_ty(*self)
 508     }
 509
 510     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 511         match self.sty {
 512             ty::TyRawPtr(ref tm) => tm.visit_with(visitor),
 513             ty::TyArray(typ, _sz) => typ.visit_with(visitor),
 514             ty::TySlice(typ) => typ.visit_with(visitor),
 515             ty::TyAdt(_, substs) => substs.visit_with(visitor),
 516             ty::TyDynamic(ref trait_ty, ref reg) =>
 517                 trait_ty.visit_with(visitor) || reg.visit_with(visitor),
 518             ty::TyTuple(ts, _) => ts.visit_with(visitor),
 519             ty::TyFnDef(_, substs, ref f) => {
 520                 substs.visit_with(visitor) || f.visit_with(visitor)
 521             }
 522             ty::TyFnPtr(ref f) => f.visit_with(visitor),
 523             ty::TyRef(r, ref tm) => r.visit_with(visitor) || tm.visit_with(visitor),
 524             ty::TyClosure(_did, ref substs) => substs.visit_with(visitor),
 525             ty::TyProjection(ref data) => data.visit_with(visitor),
 526             ty::TyAnon(_, ref substs) => substs.visit_with(visitor),
 527             ty::TyBool | ty::TyChar | ty::TyStr | ty::TyInt(_) |
 528             ty::TyUint(_) | ty::TyFloat(_) | ty::TyError | ty::TyInfer(_) |
 529             ty::TyParam(..) | ty::TyNever => false,
 530         }
 531     }
 532
 533     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 534         visitor.visit_ty(self)
 535     }
 536 }
 537
 538 impl<'tcx> TypeFoldable<'tcx> for ty::TypeAndMut<'tcx> {
 539     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 540         ty::TypeAndMut { ty: self.ty.fold_with(folder), mutbl: self.mutbl }
 541     }
 542
 543     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 544         folder.fold_mt(self)
 545     }
 546
 547     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 548         self.ty.visit_with(visitor)
 549     }
 550 }
 551
 552 impl<'tcx> TypeFoldable<'tcx> for ty::FnSig<'tcx> {
 553     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 554         let inputs_and_output = self.inputs_and_output.fold_with(folder);
 555         ty::FnSig {
 556             inputs_and_output: folder.tcx().intern_type_list(&inputs_and_output),
 557             variadic: self.variadic,
 558             unsafety: self.unsafety,
 559             abi: self.abi,
 560         }
 561     }
 562
 563     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 564         folder.fold_fn_sig(self)
 565     }
 566
 567     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 568         self.inputs().iter().any(|i| i.visit_with(visitor)) ||
 569         self.output().visit_with(visitor)
 570     }
 571 }
 572
 573 impl<'tcx> TypeFoldable<'tcx> for ty::TraitRef<'tcx> {
 574     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 575         ty::TraitRef {
 576             def_id: self.def_id,
 577             substs: self.substs.fold_with(folder),
 578         }
 579     }
 580
 581     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 582         self.substs.visit_with(visitor)
 583     }
 584
 585     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 586         visitor.visit_trait_ref(*self)
 587     }
 588 }
 589
 590 impl<'tcx> TypeFoldable<'tcx> for ty::ExistentialTraitRef<'tcx> {
 591     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 592         ty::ExistentialTraitRef {
 593             def_id: self.def_id,
 594             substs: self.substs.fold_with(folder),
 595         }
 596     }
 597
 598     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 599         self.substs.visit_with(visitor)
 600     }
 601 }
 602
 603 impl<'tcx> TypeFoldable<'tcx> for ty::ImplHeader<'tcx> {
 604     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 605         ty::ImplHeader {
 606             impl_def_id: self.impl_def_id,
 607             self_ty: self.self_ty.fold_with(folder),
 608             trait_ref: self.trait_ref.map(|t| t.fold_with(folder)),
 609             predicates: self.predicates.iter().map(|p| p.fold_with(folder)).collect(),
 610         }
 611     }
 612
 613     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 614         folder.fold_impl_header(self)
 615     }
 616
 617     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 618         self.self_ty.visit_with(visitor) ||
 619             self.trait_ref.map(|r| r.visit_with(visitor)).unwrap_or(false) ||
 620             self.predicates.iter().any(|p| p.visit_with(visitor))
 621     }
 622 }
 623
 624 impl<'tcx> TypeFoldable<'tcx> for ty::Region<'tcx> {
 625     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, _folder: &mut F) -> Self {
 626         *self
 627     }
 628
 629     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 630         folder.fold_region(*self)
 631     }
 632
 633     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _visitor: &mut V) -> bool {
 634         false
 635     }
 636
 637     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 638         visitor.visit_region(*self)
 639     }
 640 }
 641
 642 impl<'tcx> TypeFoldable<'tcx> for ty::ClosureSubsts<'tcx> {
 643     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 644         ty::ClosureSubsts {
 645             substs: self.substs.fold_with(folder),
 646         }
 647     }
 648
 649     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 650         self.substs.visit_with(visitor)
 651     }
 652 }
 653
 654 impl<'tcx> TypeFoldable<'tcx> for ty::ItemSubsts<'tcx> {
 655     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 656         ty::ItemSubsts {
 657             substs: self.substs.fold_with(folder),
 658         }
 659     }
 660
 661     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 662         self.substs.visit_with(visitor)
 663     }
 664 }
 665
 666 impl<'tcx> TypeFoldable<'tcx> for ty::adjustment::AutoBorrow<'tcx> {
 667     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 668         match *self {
 669             ty::adjustment::AutoBorrow::Ref(ref r, m) => {
 670                 ty::adjustment::AutoBorrow::Ref(r.fold_with(folder), m)
 671             }
 672             ty::adjustment::AutoBorrow::RawPtr(m) => ty::adjustment::AutoBorrow::RawPtr(m)
 673         }
 674     }
 675
 676     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 677         folder.fold_autoref(self)
 678     }
 679
 680     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 681         match *self {
 682             ty::adjustment::AutoBorrow::Ref(r, _m) => r.visit_with(visitor),
 683             ty::adjustment::AutoBorrow::RawPtr(_m) => false,
 684         }
 685     }
 686 }
 687
 688 impl<'tcx> TypeFoldable<'tcx> for ty::GenericPredicates<'tcx> {
 689     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 690         ty::GenericPredicates {
 691             parent: self.parent,
 692             predicates: self.predicates.fold_with(folder),
 693         }
 694     }
 695
 696     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 697         self.predicates.visit_with(visitor)
 698     }
 699 }
 700
 701 impl<'tcx> TypeFoldable<'tcx> for ty::Predicate<'tcx> {
 702     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 703         match *self {
 704             ty::Predicate::Trait(ref a) =>
 705                 ty::Predicate::Trait(a.fold_with(folder)),
 706             ty::Predicate::Equate(ref binder) =>
 707                 ty::Predicate::Equate(binder.fold_with(folder)),
 708             ty::Predicate::Subtype(ref binder) =>
 709                 ty::Predicate::Subtype(binder.fold_with(folder)),
 710             ty::Predicate::RegionOutlives(ref binder) =>
 711                 ty::Predicate::RegionOutlives(binder.fold_with(folder)),
 712             ty::Predicate::TypeOutlives(ref binder) =>
 713                 ty::Predicate::TypeOutlives(binder.fold_with(folder)),
 714             ty::Predicate::Projection(ref binder) =>
 715                 ty::Predicate::Projection(binder.fold_with(folder)),
 716             ty::Predicate::WellFormed(data) =>
 717                 ty::Predicate::WellFormed(data.fold_with(folder)),
 718             ty::Predicate::ClosureKind(closure_def_id, kind) =>
 719                 ty::Predicate::ClosureKind(closure_def_id, kind),
 720             ty::Predicate::ObjectSafe(trait_def_id) =>
 721                 ty::Predicate::ObjectSafe(trait_def_id),
 722         }
 723     }
 724
 725     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 726         match *self {
 727             ty::Predicate::Trait(ref a) => a.visit_with(visitor),
 728             ty::Predicate::Equate(ref binder) => binder.visit_with(visitor),
 729             ty::Predicate::Subtype(ref binder) => binder.visit_with(visitor),
 730             ty::Predicate::RegionOutlives(ref binder) => binder.visit_with(visitor),
 731             ty::Predicate::TypeOutlives(ref binder) => binder.visit_with(visitor),
 732             ty::Predicate::Projection(ref binder) => binder.visit_with(visitor),
 733             ty::Predicate::WellFormed(data) => data.visit_with(visitor),
 734             ty::Predicate::ClosureKind(_closure_def_id, _kind) => false,
 735             ty::Predicate::ObjectSafe(_trait_def_id) => false,
 736         }
 737     }
 738 }
 739
 740 impl<'tcx> TypeFoldable<'tcx> for ty::ProjectionPredicate<'tcx> {
 741     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 742         ty::ProjectionPredicate {
 743             projection_ty: self.projection_ty.fold_with(folder),
 744             ty: self.ty.fold_with(folder),
 745         }
 746     }
 747
 748     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 749         self.projection_ty.visit_with(visitor) || self.ty.visit_with(visitor)
 750     }
 751 }
 752
 753 impl<'tcx> TypeFoldable<'tcx> for ty::ExistentialProjection<'tcx> {
 754     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 755         ty::ExistentialProjection {
 756             trait_ref: self.trait_ref.fold_with(folder),
 757             item_name: self.item_name,
 758             ty: self.ty.fold_with(folder),
 759         }
 760     }
 761
 762     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 763         self.trait_ref.visit_with(visitor) || self.ty.visit_with(visitor)
 764     }
 765 }
 766
 767 impl<'tcx> TypeFoldable<'tcx> for ty::ProjectionTy<'tcx> {
 768     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 769         ty::ProjectionTy {
 770             trait_ref: self.trait_ref.fold_with(folder),
 771             item_def_id: self.item_def_id,
 772         }
 773     }
 774
 775     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 776         self.trait_ref.visit_with(visitor)
 777     }
 778 }
 779
 780 impl<'tcx> TypeFoldable<'tcx> for ty::InstantiatedPredicates<'tcx> {
 781     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 782         ty::InstantiatedPredicates {
 783             predicates: self.predicates.fold_with(folder),
 784         }
 785     }
 786
 787     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 788         self.predicates.visit_with(visitor)
 789     }
 790 }
 791
 792 impl<'tcx> TypeFoldable<'tcx> for ty::EquatePredicate<'tcx> {
 793     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 794         ty::EquatePredicate(self.0.fold_with(folder), self.1.fold_with(folder))
 795     }
 796
 797     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 798         self.0.visit_with(visitor) || self.1.visit_with(visitor)
 799     }
 800 }
 801
 802 impl<'tcx> TypeFoldable<'tcx> for ty::SubtypePredicate<'tcx> {
 803     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 804         ty::SubtypePredicate {
 805             a_is_expected: self.a_is_expected,
 806             a: self.a.fold_with(folder),
 807             b: self.b.fold_with(folder)
 808         }
 809     }
 810
 811     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 812         self.a.visit_with(visitor) || self.b.visit_with(visitor)
 813     }
 814 }
 815
 816 impl<'tcx> TypeFoldable<'tcx> for ty::TraitPredicate<'tcx> {
 817     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 818         ty::TraitPredicate {
 819             trait_ref: self.trait_ref.fold_with(folder)
 820         }
 821     }
 822
 823     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 824         self.trait_ref.visit_with(visitor)
 825     }
 826 }
 827
 828 impl<'tcx,T,U> TypeFoldable<'tcx> for ty::OutlivesPredicate<T,U>
 829     where T : TypeFoldable<'tcx>,
 830           U : TypeFoldable<'tcx>,
 831 {
 832     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 833         ty::OutlivesPredicate(self.0.fold_with(folder),
 834                               self.1.fold_with(folder))
 835     }
 836
 837     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 838         self.0.visit_with(visitor) || self.1.visit_with(visitor)
 839     }
 840 }
 841
 842 impl<'tcx> TypeFoldable<'tcx> for ty::ClosureUpvar<'tcx> {
 843     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 844         ty::ClosureUpvar {
 845             def: self.def,
 846             span: self.span,
 847             ty: self.ty.fold_with(folder),
 848         }
 849     }
 850
 851     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 852         self.ty.visit_with(visitor)
 853     }
 854 }
 855
 856 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for ty::error::ExpectedFound<T> {
 857     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 858         ty::error::ExpectedFound {
 859             expected: self.expected.fold_with(folder),
 860             found: self.found.fold_with(folder),
 861         }
 862     }
 863
 864     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 865         self.expected.visit_with(visitor) || self.found.visit_with(visitor)
 866     }
 867 }
 868
 869 impl<'tcx, T: TypeFoldable<'tcx>, I: Idx> TypeFoldable<'tcx> for IndexVec<I, T> {
 870     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 871         self.iter().map(|x| x.fold_with(folder)).collect()
 872     }
 873
 874     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 875         self.iter().any(|t| t.visit_with(visitor))
 876     }
 877 }