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 {
 139                 trait_ref: trait_ref,
 140                 item_name: self.item_name
 141             }
 142         })
 143     }
 144 }
 145
 146 impl<'a, 'tcx> Lift<'tcx> for ty::ProjectionPredicate<'a> {
 147     type Lifted = ty::ProjectionPredicate<'tcx>;
 148     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>)
 149                              -> Option<ty::ProjectionPredicate<'tcx>> {
 150         tcx.lift(&(self.projection_ty, self.ty)).map(|(projection_ty, ty)| {
 151             ty::ProjectionPredicate {
 152                 projection_ty: projection_ty,
 153                 ty: ty
 154             }
 155         })
 156     }
 157 }
 158
 159 impl<'a, 'tcx> Lift<'tcx> for ty::ExistentialProjection<'a> {
 160     type Lifted = ty::ExistentialProjection<'tcx>;
 161     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 162         tcx.lift(&(self.trait_ref, self.ty)).map(|(trait_ref, ty)| {
 163             ty::ExistentialProjection {
 164                 trait_ref: trait_ref,
 165                 item_name: self.item_name,
 166                 ty: ty
 167             }
 168         })
 169     }
 170 }
 171
 172 impl<'a, 'tcx> Lift<'tcx> for ty::Predicate<'a> {
 173     type Lifted = ty::Predicate<'tcx>;
 174     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 175         match *self {
 176             ty::Predicate::Trait(ref binder) => {
 177                 tcx.lift(binder).map(ty::Predicate::Trait)
 178             }
 179             ty::Predicate::Equate(ref binder) => {
 180                 tcx.lift(binder).map(ty::Predicate::Equate)
 181             }
 182             ty::Predicate::Subtype(ref binder) => {
 183                 tcx.lift(binder).map(ty::Predicate::Subtype)
 184             }
 185             ty::Predicate::RegionOutlives(ref binder) => {
 186                 tcx.lift(binder).map(ty::Predicate::RegionOutlives)
 187             }
 188             ty::Predicate::TypeOutlives(ref binder) => {
 189                 tcx.lift(binder).map(ty::Predicate::TypeOutlives)
 190             }
 191             ty::Predicate::Projection(ref binder) => {
 192                 tcx.lift(binder).map(ty::Predicate::Projection)
 193             }
 194             ty::Predicate::WellFormed(ty) => {
 195                 tcx.lift(&ty).map(ty::Predicate::WellFormed)
 196             }
 197             ty::Predicate::ClosureKind(closure_def_id, kind) => {
 198                 Some(ty::Predicate::ClosureKind(closure_def_id, kind))
 199             }
 200             ty::Predicate::ObjectSafe(trait_def_id) => {
 201                 Some(ty::Predicate::ObjectSafe(trait_def_id))
 202             }
 203         }
 204     }
 205 }
 206
 207 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for ty::Binder<T> {
 208     type Lifted = ty::Binder<T::Lifted>;
 209     fn lift_to_tcx<'a, 'gcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 210         tcx.lift(&self.0).map(|x| ty::Binder(x))
 211     }
 212 }
 213
 214 impl<'a, 'tcx> Lift<'tcx> for ty::ClosureSubsts<'a> {
 215     type Lifted = ty::ClosureSubsts<'tcx>;
 216     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 217         tcx.lift(&self.substs).map(|substs| {
 218             ty::ClosureSubsts { substs: substs }
 219         })
 220     }
 221 }
 222
 223 impl<'a, 'tcx> Lift<'tcx> for ty::ItemSubsts<'a> {
 224     type Lifted = ty::ItemSubsts<'tcx>;
 225     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 226         tcx.lift(&self.substs).map(|substs| {
 227             ty::ItemSubsts {
 228                 substs: substs
 229             }
 230         })
 231     }
 232 }
 233
 234 impl<'a, 'tcx> Lift<'tcx> for ty::adjustment::AutoBorrow<'a> {
 235     type Lifted = ty::adjustment::AutoBorrow<'tcx>;
 236     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 237         match *self {
 238             ty::adjustment::AutoBorrow::Ref(r, m) => {
 239                 tcx.lift(&r).map(|r| ty::adjustment::AutoBorrow::Ref(r, m))
 240             }
 241             ty::adjustment::AutoBorrow::RawPtr(m) => {
 242                 Some(ty::adjustment::AutoBorrow::RawPtr(m))
 243             }
 244         }
 245     }
 246 }
 247
 248 impl<'a, 'tcx> Lift<'tcx> for ty::FnSig<'a> {
 249     type Lifted = ty::FnSig<'tcx>;
 250     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 251         tcx.lift(&self.inputs_and_output).map(|x| {
 252             ty::FnSig {
 253                 inputs_and_output: x,
 254                 variadic: self.variadic,
 255                 unsafety: self.unsafety,
 256                 abi: self.abi,
 257             }
 258         })
 259     }
 260 }
 261
 262 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for ty::error::ExpectedFound<T> {
 263     type Lifted = ty::error::ExpectedFound<T::Lifted>;
 264     fn lift_to_tcx<'a, 'gcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 265         tcx.lift(&self.expected).and_then(|expected| {
 266             tcx.lift(&self.found).map(|found| {
 267                 ty::error::ExpectedFound {
 268                     expected: expected,
 269                     found: found
 270                 }
 271             })
 272         })
 273     }
 274 }
 275
 276 impl<'a, 'tcx> Lift<'tcx> for type_variable::Default<'a> {
 277     type Lifted = type_variable::Default<'tcx>;
 278     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 279         tcx.lift(&self.ty).map(|ty| {
 280             type_variable::Default {
 281                 ty: ty,
 282                 origin_span: self.origin_span,
 283                 def_id: self.def_id
 284             }
 285         })
 286     }
 287 }
 288
 289 impl<'a, 'tcx> Lift<'tcx> for ty::error::TypeError<'a> {
 290     type Lifted = ty::error::TypeError<'tcx>;
 291     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 292         use ty::error::TypeError::*;
 293
 294         Some(match *self {
 295             Mismatch => Mismatch,
 296             UnsafetyMismatch(x) => UnsafetyMismatch(x),
 297             AbiMismatch(x) => AbiMismatch(x),
 298             Mutability => Mutability,
 299             TupleSize(x) => TupleSize(x),
 300             FixedArraySize(x) => FixedArraySize(x),
 301             ArgCount => ArgCount,
 302             RegionsDoesNotOutlive(a, b) => {
 303                 return tcx.lift(&(a, b)).map(|(a, b)| RegionsDoesNotOutlive(a, b))
 304             }
 305             RegionsNotSame(a, b) => {
 306                 return tcx.lift(&(a, b)).map(|(a, b)| RegionsNotSame(a, b))
 307             }
 308             RegionsNoOverlap(a, b) => {
 309                 return tcx.lift(&(a, b)).map(|(a, b)| RegionsNoOverlap(a, b))
 310             }
 311             RegionsInsufficientlyPolymorphic(a, b, ref c) => {
 312                 let c = c.clone();
 313                 return tcx.lift(&b).map(|b| RegionsInsufficientlyPolymorphic(a, b, c))
 314             }
 315             RegionsOverlyPolymorphic(a, b, ref c) => {
 316                 let c = c.clone();
 317                 return tcx.lift(&b).map(|b| RegionsOverlyPolymorphic(a, b, c))
 318             }
 319             IntMismatch(x) => IntMismatch(x),
 320             FloatMismatch(x) => FloatMismatch(x),
 321             Traits(x) => Traits(x),
 322             VariadicMismatch(x) => VariadicMismatch(x),
 323             CyclicTy => CyclicTy,
 324             ProjectionNameMismatched(x) => ProjectionNameMismatched(x),
 325             ProjectionBoundsLength(x) => ProjectionBoundsLength(x),
 326
 327             Sorts(ref x) => return tcx.lift(x).map(Sorts),
 328             TyParamDefaultMismatch(ref x) => {
 329                 return tcx.lift(x).map(TyParamDefaultMismatch)
 330             }
 331             ExistentialMismatch(ref x) => return tcx.lift(x).map(ExistentialMismatch)
 332         })
 333     }
 334 }
 335
 336 ///////////////////////////////////////////////////////////////////////////
 337 // TypeFoldable implementations.
 338 //
 339 // Ideally, each type should invoke `folder.fold_foo(self)` and
 340 // nothing else. In some cases, though, we haven't gotten around to
 341 // adding methods on the `folder` yet, and thus the folding is
 342 // hard-coded here. This is less-flexible, because folders cannot
 343 // override the behavior, but there are a lot of random types and one
 344 // can easily refactor the folding into the TypeFolder trait as
 345 // needed.
 346
 347 macro_rules! CopyImpls {
 348     ($($ty:ty),+) => {
 349         $(
 350             impl<'tcx> TypeFoldable<'tcx> for $ty {
 351                 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, _: &mut F) -> $ty {
 352                     *self
 353                 }
 354
 355                 fn super_visit_with<F: TypeVisitor<'tcx>>(&self, _: &mut F) -> bool {
 356                     false
 357                 }
 358             }
 359         )+
 360     }
 361 }
 362
 363 CopyImpls! { (), hir::Unsafety, abi::Abi }
 364
 365 impl<'tcx, T:TypeFoldable<'tcx>, U:TypeFoldable<'tcx>> TypeFoldable<'tcx> for (T, U) {
 366     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> (T, U) {
 367         (self.0.fold_with(folder), self.1.fold_with(folder))
 368     }
 369
 370     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 371         self.0.visit_with(visitor) || self.1.visit_with(visitor)
 372     }
 373 }
 374
 375 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Option<T> {
 376     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 377         self.as_ref().map(|t| t.fold_with(folder))
 378     }
 379
 380     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 381         self.iter().any(|t| t.visit_with(visitor))
 382     }
 383 }
 384
 385 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Rc<T> {
 386     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 387         Rc::new((**self).fold_with(folder))
 388     }
 389
 390     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 391         (**self).visit_with(visitor)
 392     }
 393 }
 394
 395 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Box<T> {
 396     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 397         let content: T = (**self).fold_with(folder);
 398         box content
 399     }
 400
 401     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 402         (**self).visit_with(visitor)
 403     }
 404 }
 405
 406 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Vec<T> {
 407     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 408         self.iter().map(|t| t.fold_with(folder)).collect()
 409     }
 410
 411     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 412         self.iter().any(|t| t.visit_with(visitor))
 413     }
 414 }
 415
 416 impl<'tcx, T:TypeFoldable<'tcx>> TypeFoldable<'tcx> for ty::Binder<T> {
 417     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 418         ty::Binder(self.0.fold_with(folder))
 419     }
 420
 421     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 422         folder.fold_binder(self)
 423     }
 424
 425     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 426         self.0.visit_with(visitor)
 427     }
 428
 429     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 430         visitor.visit_binder(self)
 431     }
 432 }
 433
 434 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::Slice<ty::ExistentialPredicate<'tcx>> {
 435     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 436         let v = self.iter().map(|p| p.fold_with(folder)).collect::<AccumulateVec<[_; 8]>>();
 437         folder.tcx().intern_existential_predicates(&v)
 438     }
 439
 440     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 441         self.iter().any(|p| p.visit_with(visitor))
 442     }
 443 }
 444
 445 impl<'tcx> TypeFoldable<'tcx> for ty::ExistentialPredicate<'tcx> {
 446     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self  {
 447         use ty::ExistentialPredicate::*;
 448         match *self {
 449             Trait(ref tr) => Trait(tr.fold_with(folder)),
 450             Projection(ref p) => Projection(p.fold_with(folder)),
 451             AutoTrait(did) => AutoTrait(did),
 452         }
 453     }
 454
 455     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 456         match *self {
 457             ty::ExistentialPredicate::Trait(ref tr) => tr.visit_with(visitor),
 458             ty::ExistentialPredicate::Projection(ref p) => p.visit_with(visitor),
 459             ty::ExistentialPredicate::AutoTrait(_) => false,
 460         }
 461     }
 462 }
 463
 464 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::Slice<Ty<'tcx>> {
 465     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 466         let v = self.iter().map(|t| t.fold_with(folder)).collect::<AccumulateVec<[_; 8]>>();
 467         folder.tcx().intern_type_list(&v)
 468     }
 469
 470     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 471         self.iter().any(|t| t.visit_with(visitor))
 472     }
 473 }
 474
 475 impl<'tcx> TypeFoldable<'tcx> for Ty<'tcx> {
 476     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 477         let sty = match self.sty {
 478             ty::TyRawPtr(tm) => ty::TyRawPtr(tm.fold_with(folder)),
 479             ty::TyArray(typ, sz) => ty::TyArray(typ.fold_with(folder), sz),
 480             ty::TySlice(typ) => ty::TySlice(typ.fold_with(folder)),
 481             ty::TyAdt(tid, substs) => ty::TyAdt(tid, substs.fold_with(folder)),
 482             ty::TyDynamic(ref trait_ty, ref region) =>
 483                 ty::TyDynamic(trait_ty.fold_with(folder), region.fold_with(folder)),
 484             ty::TyTuple(ts, defaulted) => ty::TyTuple(ts.fold_with(folder), defaulted),
 485             ty::TyFnDef(def_id, substs, f) => {
 486                 ty::TyFnDef(def_id,
 487                             substs.fold_with(folder),
 488                             f.fold_with(folder))
 489             }
 490             ty::TyFnPtr(f) => ty::TyFnPtr(f.fold_with(folder)),
 491             ty::TyRef(ref r, tm) => {
 492                 ty::TyRef(r.fold_with(folder), tm.fold_with(folder))
 493             }
 494             ty::TyClosure(did, substs) => ty::TyClosure(did, substs.fold_with(folder)),
 495             ty::TyProjection(ref data) => ty::TyProjection(data.fold_with(folder)),
 496             ty::TyAnon(did, substs) => ty::TyAnon(did, substs.fold_with(folder)),
 497             ty::TyBool | ty::TyChar | ty::TyStr | ty::TyInt(_) |
 498             ty::TyUint(_) | ty::TyFloat(_) | ty::TyError | ty::TyInfer(_) |
 499             ty::TyParam(..) | ty::TyNever => return self
 500         };
 501
 502         if self.sty == sty {
 503             self
 504         } else {
 505             folder.tcx().mk_ty(sty)
 506         }
 507     }
 508
 509     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 510         folder.fold_ty(*self)
 511     }
 512
 513     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 514         match self.sty {
 515             ty::TyRawPtr(ref tm) => tm.visit_with(visitor),
 516             ty::TyArray(typ, _sz) => typ.visit_with(visitor),
 517             ty::TySlice(typ) => typ.visit_with(visitor),
 518             ty::TyAdt(_, substs) => substs.visit_with(visitor),
 519             ty::TyDynamic(ref trait_ty, ref reg) =>
 520                 trait_ty.visit_with(visitor) || reg.visit_with(visitor),
 521             ty::TyTuple(ts, _) => ts.visit_with(visitor),
 522             ty::TyFnDef(_, substs, ref f) => {
 523                 substs.visit_with(visitor) || f.visit_with(visitor)
 524             }
 525             ty::TyFnPtr(ref f) => f.visit_with(visitor),
 526             ty::TyRef(r, ref tm) => r.visit_with(visitor) || tm.visit_with(visitor),
 527             ty::TyClosure(_did, ref substs) => substs.visit_with(visitor),
 528             ty::TyProjection(ref data) => data.visit_with(visitor),
 529             ty::TyAnon(_, ref substs) => substs.visit_with(visitor),
 530             ty::TyBool | ty::TyChar | ty::TyStr | ty::TyInt(_) |
 531             ty::TyUint(_) | ty::TyFloat(_) | ty::TyError | ty::TyInfer(_) |
 532             ty::TyParam(..) | ty::TyNever => false,
 533         }
 534     }
 535
 536     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 537         visitor.visit_ty(self)
 538     }
 539 }
 540
 541 impl<'tcx> TypeFoldable<'tcx> for ty::TypeAndMut<'tcx> {
 542     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 543         ty::TypeAndMut { ty: self.ty.fold_with(folder), mutbl: self.mutbl }
 544     }
 545
 546     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 547         folder.fold_mt(self)
 548     }
 549
 550     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 551         self.ty.visit_with(visitor)
 552     }
 553 }
 554
 555 impl<'tcx> TypeFoldable<'tcx> for ty::FnSig<'tcx> {
 556     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 557         let inputs_and_output = self.inputs_and_output.fold_with(folder);
 558         ty::FnSig {
 559             inputs_and_output: folder.tcx().intern_type_list(&inputs_and_output),
 560             variadic: self.variadic,
 561             unsafety: self.unsafety,
 562             abi: self.abi,
 563         }
 564     }
 565
 566     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 567         folder.fold_fn_sig(self)
 568     }
 569
 570     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 571         self.inputs().iter().any(|i| i.visit_with(visitor)) ||
 572         self.output().visit_with(visitor)
 573     }
 574 }
 575
 576 impl<'tcx> TypeFoldable<'tcx> for ty::TraitRef<'tcx> {
 577     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 578         ty::TraitRef {
 579             def_id: self.def_id,
 580             substs: self.substs.fold_with(folder),
 581         }
 582     }
 583
 584     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 585         self.substs.visit_with(visitor)
 586     }
 587
 588     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 589         visitor.visit_trait_ref(*self)
 590     }
 591 }
 592
 593 impl<'tcx> TypeFoldable<'tcx> for ty::ExistentialTraitRef<'tcx> {
 594     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 595         ty::ExistentialTraitRef {
 596             def_id: self.def_id,
 597             substs: self.substs.fold_with(folder),
 598         }
 599     }
 600
 601     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 602         self.substs.visit_with(visitor)
 603     }
 604 }
 605
 606 impl<'tcx> TypeFoldable<'tcx> for ty::ImplHeader<'tcx> {
 607     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 608         ty::ImplHeader {
 609             impl_def_id: self.impl_def_id,
 610             self_ty: self.self_ty.fold_with(folder),
 611             trait_ref: self.trait_ref.map(|t| t.fold_with(folder)),
 612             predicates: self.predicates.iter().map(|p| p.fold_with(folder)).collect(),
 613         }
 614     }
 615
 616     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 617         folder.fold_impl_header(self)
 618     }
 619
 620     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 621         self.self_ty.visit_with(visitor) ||
 622             self.trait_ref.map(|r| r.visit_with(visitor)).unwrap_or(false) ||
 623             self.predicates.iter().any(|p| p.visit_with(visitor))
 624     }
 625 }
 626
 627 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::Region {
 628     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, _folder: &mut F) -> Self {
 629         *self
 630     }
 631
 632     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 633         folder.fold_region(*self)
 634     }
 635
 636     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _visitor: &mut V) -> bool {
 637         false
 638     }
 639
 640     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 641         visitor.visit_region(*self)
 642     }
 643 }
 644
 645 impl<'tcx> TypeFoldable<'tcx> for ty::ClosureSubsts<'tcx> {
 646     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 647         ty::ClosureSubsts {
 648             substs: self.substs.fold_with(folder),
 649         }
 650     }
 651
 652     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 653         self.substs.visit_with(visitor)
 654     }
 655 }
 656
 657 impl<'tcx> TypeFoldable<'tcx> for ty::ItemSubsts<'tcx> {
 658     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 659         ty::ItemSubsts {
 660             substs: self.substs.fold_with(folder),
 661         }
 662     }
 663
 664     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 665         self.substs.visit_with(visitor)
 666     }
 667 }
 668
 669 impl<'tcx> TypeFoldable<'tcx> for ty::adjustment::AutoBorrow<'tcx> {
 670     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 671         match *self {
 672             ty::adjustment::AutoBorrow::Ref(ref r, m) => {
 673                 ty::adjustment::AutoBorrow::Ref(r.fold_with(folder), m)
 674             }
 675             ty::adjustment::AutoBorrow::RawPtr(m) => ty::adjustment::AutoBorrow::RawPtr(m)
 676         }
 677     }
 678
 679     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 680         folder.fold_autoref(self)
 681     }
 682
 683     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 684         match *self {
 685             ty::adjustment::AutoBorrow::Ref(r, _m) => r.visit_with(visitor),
 686             ty::adjustment::AutoBorrow::RawPtr(_m) => false,
 687         }
 688     }
 689 }
 690
 691 impl<'tcx> TypeFoldable<'tcx> for ty::GenericPredicates<'tcx> {
 692     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 693         ty::GenericPredicates {
 694             parent: self.parent,
 695             predicates: self.predicates.fold_with(folder),
 696         }
 697     }
 698
 699     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 700         self.predicates.visit_with(visitor)
 701     }
 702 }
 703
 704 impl<'tcx> TypeFoldable<'tcx> for ty::Predicate<'tcx> {
 705     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 706         match *self {
 707             ty::Predicate::Trait(ref a) =>
 708                 ty::Predicate::Trait(a.fold_with(folder)),
 709             ty::Predicate::Equate(ref binder) =>
 710                 ty::Predicate::Equate(binder.fold_with(folder)),
 711             ty::Predicate::Subtype(ref binder) =>
 712                 ty::Predicate::Subtype(binder.fold_with(folder)),
 713             ty::Predicate::RegionOutlives(ref binder) =>
 714                 ty::Predicate::RegionOutlives(binder.fold_with(folder)),
 715             ty::Predicate::TypeOutlives(ref binder) =>
 716                 ty::Predicate::TypeOutlives(binder.fold_with(folder)),
 717             ty::Predicate::Projection(ref binder) =>
 718                 ty::Predicate::Projection(binder.fold_with(folder)),
 719             ty::Predicate::WellFormed(data) =>
 720                 ty::Predicate::WellFormed(data.fold_with(folder)),
 721             ty::Predicate::ClosureKind(closure_def_id, kind) =>
 722                 ty::Predicate::ClosureKind(closure_def_id, kind),
 723             ty::Predicate::ObjectSafe(trait_def_id) =>
 724                 ty::Predicate::ObjectSafe(trait_def_id),
 725         }
 726     }
 727
 728     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 729         match *self {
 730             ty::Predicate::Trait(ref a) => a.visit_with(visitor),
 731             ty::Predicate::Equate(ref binder) => binder.visit_with(visitor),
 732             ty::Predicate::Subtype(ref binder) => binder.visit_with(visitor),
 733             ty::Predicate::RegionOutlives(ref binder) => binder.visit_with(visitor),
 734             ty::Predicate::TypeOutlives(ref binder) => binder.visit_with(visitor),
 735             ty::Predicate::Projection(ref binder) => binder.visit_with(visitor),
 736             ty::Predicate::WellFormed(data) => data.visit_with(visitor),
 737             ty::Predicate::ClosureKind(_closure_def_id, _kind) => false,
 738             ty::Predicate::ObjectSafe(_trait_def_id) => false,
 739         }
 740     }
 741 }
 742
 743 impl<'tcx> TypeFoldable<'tcx> for ty::ProjectionPredicate<'tcx> {
 744     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 745         ty::ProjectionPredicate {
 746             projection_ty: self.projection_ty.fold_with(folder),
 747             ty: self.ty.fold_with(folder),
 748         }
 749     }
 750
 751     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 752         self.projection_ty.visit_with(visitor) || self.ty.visit_with(visitor)
 753     }
 754 }
 755
 756 impl<'tcx> TypeFoldable<'tcx> for ty::ExistentialProjection<'tcx> {
 757     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 758         ty::ExistentialProjection {
 759             trait_ref: self.trait_ref.fold_with(folder),
 760             item_name: self.item_name,
 761             ty: self.ty.fold_with(folder),
 762         }
 763     }
 764
 765     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 766         self.trait_ref.visit_with(visitor) || self.ty.visit_with(visitor)
 767     }
 768 }
 769
 770 impl<'tcx> TypeFoldable<'tcx> for ty::ProjectionTy<'tcx> {
 771     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 772         ty::ProjectionTy {
 773             trait_ref: self.trait_ref.fold_with(folder),
 774             item_name: self.item_name,
 775         }
 776     }
 777
 778     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 779         self.trait_ref.visit_with(visitor)
 780     }
 781 }
 782
 783 impl<'tcx> TypeFoldable<'tcx> for ty::InstantiatedPredicates<'tcx> {
 784     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 785         ty::InstantiatedPredicates {
 786             predicates: self.predicates.fold_with(folder),
 787         }
 788     }
 789
 790     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 791         self.predicates.visit_with(visitor)
 792     }
 793 }
 794
 795 impl<'tcx> TypeFoldable<'tcx> for ty::EquatePredicate<'tcx> {
 796     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 797         ty::EquatePredicate(self.0.fold_with(folder), self.1.fold_with(folder))
 798     }
 799
 800     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 801         self.0.visit_with(visitor) || self.1.visit_with(visitor)
 802     }
 803 }
 804
 805 impl<'tcx> TypeFoldable<'tcx> for ty::SubtypePredicate<'tcx> {
 806     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 807         ty::SubtypePredicate {
 808             a_is_expected: self.a_is_expected,
 809             a: self.a.fold_with(folder),
 810             b: self.b.fold_with(folder)
 811         }
 812     }
 813
 814     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 815         self.a.visit_with(visitor) || self.b.visit_with(visitor)
 816     }
 817 }
 818
 819 impl<'tcx> TypeFoldable<'tcx> for ty::TraitPredicate<'tcx> {
 820     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 821         ty::TraitPredicate {
 822             trait_ref: self.trait_ref.fold_with(folder)
 823         }
 824     }
 825
 826     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 827         self.trait_ref.visit_with(visitor)
 828     }
 829 }
 830
 831 impl<'tcx,T,U> TypeFoldable<'tcx> for ty::OutlivesPredicate<T,U>
 832     where T : TypeFoldable<'tcx>,
 833           U : TypeFoldable<'tcx>,
 834 {
 835     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 836         ty::OutlivesPredicate(self.0.fold_with(folder),
 837                               self.1.fold_with(folder))
 838     }
 839
 840     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 841         self.0.visit_with(visitor) || self.1.visit_with(visitor)
 842     }
 843 }
 844
 845 impl<'tcx> TypeFoldable<'tcx> for ty::ClosureUpvar<'tcx> {
 846     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 847         ty::ClosureUpvar {
 848             def: self.def,
 849             span: self.span,
 850             ty: self.ty.fold_with(folder),
 851         }
 852     }
 853
 854     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 855         self.ty.visit_with(visitor)
 856     }
 857 }
 858
 859 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for ty::error::ExpectedFound<T> {
 860     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 861         ty::error::ExpectedFound {
 862             expected: self.expected.fold_with(folder),
 863             found: self.found.fold_with(folder),
 864         }
 865     }
 866
 867     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 868         self.expected.visit_with(visitor) || self.found.visit_with(visitor)
 869     }
 870 }
 871
 872 impl<'tcx, T: TypeFoldable<'tcx>, I: Idx> TypeFoldable<'tcx> for IndexVec<I, T> {
 873     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 874         self.iter().map(|x| x.fold_with(folder)).collect()
 875     }
 876
 877     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 878         self.iter().any(|t| t.visit_with(visitor))
 879     }
 880 }