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
  16 use std::rc::Rc;
  17 use syntax::abi;
  18
  19 use hir;
  20
  21 ///////////////////////////////////////////////////////////////////////////
  22 // Lift implementations
  23
  24 impl<'tcx, A: Lift<'tcx>, B: Lift<'tcx>> Lift<'tcx> for (A, B) {
  25     type Lifted = (A::Lifted, B::Lifted);
  26     fn lift_to_tcx<'a, 'gcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Self::Lifted> {
  27         tcx.lift(&self.0).and_then(|a| tcx.lift(&self.1).map(|b| (a, b)))
  28     }
  29 }
  30
  31 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for Option<T> {
  32     type Lifted = Option<T::Lifted>;
  33     fn lift_to_tcx<'a, 'gcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Self::Lifted> {
  34         match *self {
  35             Some(ref x) => tcx.lift(x).map(Some),
  36             None => Some(None)
  37         }
  38     }
  39 }
  40
  41 impl<'tcx, T: Lift<'tcx>, E: Lift<'tcx>> Lift<'tcx> for Result<T, E> {
  42     type Lifted = Result<T::Lifted, E::Lifted>;
  43     fn lift_to_tcx<'a, 'gcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Self::Lifted> {
  44         match *self {
  45             Ok(ref x) => tcx.lift(x).map(Ok),
  46             Err(ref e) => tcx.lift(e).map(Err)
  47         }
  48     }
  49 }
  50
  51 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for [T] {
  52     type Lifted = Vec<T::Lifted>;
  53     fn lift_to_tcx<'a, 'gcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Self::Lifted> {
  54         // type annotation needed to inform `projection_must_outlive`
  55         let mut result : Vec<<T as Lift<'tcx>>::Lifted>
  56             = Vec::with_capacity(self.len());
  57         for x in self {
  58             if let Some(value) = tcx.lift(x) {
  59                 result.push(value);
  60             } else {
  61                 return None;
  62             }
  63         }
  64         Some(result)
  65     }
  66 }
  67
  68 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for Vec<T> {
  69     type Lifted = Vec<T::Lifted>;
  70     fn lift_to_tcx<'a, 'gcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Self::Lifted> {
  71         tcx.lift(&self[..])
  72     }
  73 }
  74
  75 impl<'a, 'tcx> Lift<'tcx> for ty::TraitRef<'a> {
  76     type Lifted = ty::TraitRef<'tcx>;
  77     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
  78         tcx.lift(&self.substs).map(|substs| ty::TraitRef {
  79             def_id: self.def_id,
  80             substs: substs
  81         })
  82     }
  83 }
  84
  85 impl<'a, 'tcx> Lift<'tcx> for ty::ExistentialTraitRef<'a> {
  86     type Lifted = ty::ExistentialTraitRef<'tcx>;
  87     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
  88         tcx.lift(&self.substs).map(|substs| ty::ExistentialTraitRef {
  89             def_id: self.def_id,
  90             substs: substs
  91         })
  92     }
  93 }
  94
  95 impl<'a, 'tcx> Lift<'tcx> for ty::TraitPredicate<'a> {
  96     type Lifted = ty::TraitPredicate<'tcx>;
  97     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>)
  98                              -> Option<ty::TraitPredicate<'tcx>> {
  99         tcx.lift(&self.trait_ref).map(|trait_ref| ty::TraitPredicate {
 100             trait_ref: trait_ref
 101         })
 102     }
 103 }
 104
 105 impl<'a, 'tcx> Lift<'tcx> for ty::EquatePredicate<'a> {
 106     type Lifted = ty::EquatePredicate<'tcx>;
 107     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>)
 108                              -> Option<ty::EquatePredicate<'tcx>> {
 109         tcx.lift(&(self.0, self.1)).map(|(a, b)| ty::EquatePredicate(a, b))
 110     }
 111 }
 112
 113 impl<'tcx, A: Copy+Lift<'tcx>, B: Copy+Lift<'tcx>> Lift<'tcx> for ty::OutlivesPredicate<A, B> {
 114     type Lifted = ty::OutlivesPredicate<A::Lifted, B::Lifted>;
 115     fn lift_to_tcx<'a, 'gcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 116         tcx.lift(&(self.0, self.1)).map(|(a, b)| ty::OutlivesPredicate(a, b))
 117     }
 118 }
 119
 120 impl<'a, 'tcx> Lift<'tcx> for ty::ProjectionTy<'a> {
 121     type Lifted = ty::ProjectionTy<'tcx>;
 122     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>)
 123                              -> Option<ty::ProjectionTy<'tcx>> {
 124         tcx.lift(&self.trait_ref).map(|trait_ref| {
 125             ty::ProjectionTy {
 126                 trait_ref: trait_ref,
 127                 item_name: self.item_name
 128             }
 129         })
 130     }
 131 }
 132
 133 impl<'a, 'tcx> Lift<'tcx> for ty::ProjectionPredicate<'a> {
 134     type Lifted = ty::ProjectionPredicate<'tcx>;
 135     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>)
 136                              -> Option<ty::ProjectionPredicate<'tcx>> {
 137         tcx.lift(&(self.projection_ty, self.ty)).map(|(projection_ty, ty)| {
 138             ty::ProjectionPredicate {
 139                 projection_ty: projection_ty,
 140                 ty: ty
 141             }
 142         })
 143     }
 144 }
 145
 146 impl<'a, 'tcx> Lift<'tcx> for ty::ExistentialProjection<'a> {
 147     type Lifted = ty::ExistentialProjection<'tcx>;
 148     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 149         tcx.lift(&(self.trait_ref, self.ty)).map(|(trait_ref, ty)| {
 150             ty::ExistentialProjection {
 151                 trait_ref: trait_ref,
 152                 item_name: self.item_name,
 153                 ty: ty
 154             }
 155         })
 156     }
 157 }
 158
 159 impl<'a, 'tcx> Lift<'tcx> for ty::Predicate<'a> {
 160     type Lifted = ty::Predicate<'tcx>;
 161     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 162         match *self {
 163             ty::Predicate::Trait(ref binder) => {
 164                 tcx.lift(binder).map(ty::Predicate::Trait)
 165             }
 166             ty::Predicate::Equate(ref binder) => {
 167                 tcx.lift(binder).map(ty::Predicate::Equate)
 168             }
 169             ty::Predicate::RegionOutlives(ref binder) => {
 170                 tcx.lift(binder).map(ty::Predicate::RegionOutlives)
 171             }
 172             ty::Predicate::TypeOutlives(ref binder) => {
 173                 tcx.lift(binder).map(ty::Predicate::TypeOutlives)
 174             }
 175             ty::Predicate::Projection(ref binder) => {
 176                 tcx.lift(binder).map(ty::Predicate::Projection)
 177             }
 178             ty::Predicate::WellFormed(ty) => {
 179                 tcx.lift(&ty).map(ty::Predicate::WellFormed)
 180             }
 181             ty::Predicate::ClosureKind(closure_def_id, kind) => {
 182                 Some(ty::Predicate::ClosureKind(closure_def_id, kind))
 183             }
 184             ty::Predicate::ObjectSafe(trait_def_id) => {
 185                 Some(ty::Predicate::ObjectSafe(trait_def_id))
 186             }
 187         }
 188     }
 189 }
 190
 191 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for ty::Binder<T> {
 192     type Lifted = ty::Binder<T::Lifted>;
 193     fn lift_to_tcx<'a, 'gcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 194         tcx.lift(&self.0).map(|x| ty::Binder(x))
 195     }
 196 }
 197
 198 impl<'a, 'tcx> Lift<'tcx> for ty::ClosureSubsts<'a> {
 199     type Lifted = ty::ClosureSubsts<'tcx>;
 200     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 201         tcx.lift(&self.substs).map(|substs| {
 202             ty::ClosureSubsts { substs: substs }
 203         })
 204     }
 205 }
 206
 207 impl<'a, 'tcx> Lift<'tcx> for ty::ItemSubsts<'a> {
 208     type Lifted = ty::ItemSubsts<'tcx>;
 209     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 210         tcx.lift(&self.substs).map(|substs| {
 211             ty::ItemSubsts {
 212                 substs: substs
 213             }
 214         })
 215     }
 216 }
 217
 218 impl<'a, 'tcx> Lift<'tcx> for ty::adjustment::AutoBorrow<'a> {
 219     type Lifted = ty::adjustment::AutoBorrow<'tcx>;
 220     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 221         match *self {
 222             ty::adjustment::AutoBorrow::Ref(r, m) => {
 223                 tcx.lift(&r).map(|r| ty::adjustment::AutoBorrow::Ref(r, m))
 224             }
 225             ty::adjustment::AutoBorrow::RawPtr(m) => {
 226                 Some(ty::adjustment::AutoBorrow::RawPtr(m))
 227             }
 228         }
 229     }
 230 }
 231
 232 impl<'a, 'tcx> Lift<'tcx> for ty::FnSig<'a> {
 233     type Lifted = ty::FnSig<'tcx>;
 234     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 235         tcx.lift(&self.inputs_and_output).map(|x| {
 236             ty::FnSig {
 237                 inputs_and_output: x,
 238                 variadic: self.variadic
 239             }
 240         })
 241     }
 242 }
 243
 244 impl<'a, 'tcx> Lift<'tcx> for ty::ClosureTy<'a> {
 245     type Lifted = ty::ClosureTy<'tcx>;
 246     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 247         tcx.lift(&self.sig).map(|sig| {
 248             ty::ClosureTy {
 249                 sig: sig,
 250                 unsafety: self.unsafety,
 251                 abi: self.abi
 252             }
 253         })
 254     }
 255 }
 256
 257 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for ty::error::ExpectedFound<T> {
 258     type Lifted = ty::error::ExpectedFound<T::Lifted>;
 259     fn lift_to_tcx<'a, 'gcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 260         tcx.lift(&self.expected).and_then(|expected| {
 261             tcx.lift(&self.found).map(|found| {
 262                 ty::error::ExpectedFound {
 263                     expected: expected,
 264                     found: found
 265                 }
 266             })
 267         })
 268     }
 269 }
 270
 271 impl<'a, 'tcx> Lift<'tcx> for type_variable::Default<'a> {
 272     type Lifted = type_variable::Default<'tcx>;
 273     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 274         tcx.lift(&self.ty).map(|ty| {
 275             type_variable::Default {
 276                 ty: ty,
 277                 origin_span: self.origin_span,
 278                 def_id: self.def_id
 279             }
 280         })
 281     }
 282 }
 283
 284 impl<'a, 'tcx> Lift<'tcx> for ty::error::TypeError<'a> {
 285     type Lifted = ty::error::TypeError<'tcx>;
 286     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
 287         use ty::error::TypeError::*;
 288
 289         Some(match *self {
 290             Mismatch => Mismatch,
 291             UnsafetyMismatch(x) => UnsafetyMismatch(x),
 292             AbiMismatch(x) => AbiMismatch(x),
 293             Mutability => Mutability,
 294             TupleSize(x) => TupleSize(x),
 295             FixedArraySize(x) => FixedArraySize(x),
 296             ArgCount => ArgCount,
 297             RegionsDoesNotOutlive(a, b) => {
 298                 return tcx.lift(&(a, b)).map(|(a, b)| RegionsDoesNotOutlive(a, b))
 299             }
 300             RegionsNotSame(a, b) => {
 301                 return tcx.lift(&(a, b)).map(|(a, b)| RegionsNotSame(a, b))
 302             }
 303             RegionsNoOverlap(a, b) => {
 304                 return tcx.lift(&(a, b)).map(|(a, b)| RegionsNoOverlap(a, b))
 305             }
 306             RegionsInsufficientlyPolymorphic(a, b) => {
 307                 return tcx.lift(&b).map(|b| RegionsInsufficientlyPolymorphic(a, b))
 308             }
 309             RegionsOverlyPolymorphic(a, b) => {
 310                 return tcx.lift(&b).map(|b| RegionsOverlyPolymorphic(a, b))
 311             }
 312             IntMismatch(x) => IntMismatch(x),
 313             FloatMismatch(x) => FloatMismatch(x),
 314             Traits(x) => Traits(x),
 315             VariadicMismatch(x) => VariadicMismatch(x),
 316             CyclicTy => CyclicTy,
 317             ProjectionNameMismatched(x) => ProjectionNameMismatched(x),
 318             ProjectionBoundsLength(x) => ProjectionBoundsLength(x),
 319
 320             Sorts(ref x) => return tcx.lift(x).map(Sorts),
 321             TyParamDefaultMismatch(ref x) => {
 322                 return tcx.lift(x).map(TyParamDefaultMismatch)
 323             }
 324             ExistentialMismatch(ref x) => return tcx.lift(x).map(ExistentialMismatch)
 325         })
 326     }
 327 }
 328
 329 ///////////////////////////////////////////////////////////////////////////
 330 // TypeFoldable implementations.
 331 //
 332 // Ideally, each type should invoke `folder.fold_foo(self)` and
 333 // nothing else. In some cases, though, we haven't gotten around to
 334 // adding methods on the `folder` yet, and thus the folding is
 335 // hard-coded here. This is less-flexible, because folders cannot
 336 // override the behavior, but there are a lot of random types and one
 337 // can easily refactor the folding into the TypeFolder trait as
 338 // needed.
 339
 340 macro_rules! CopyImpls {
 341     ($($ty:ty),+) => {
 342         $(
 343             impl<'tcx> TypeFoldable<'tcx> for $ty {
 344                 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, _: &mut F) -> $ty {
 345                     *self
 346                 }
 347
 348                 fn super_visit_with<F: TypeVisitor<'tcx>>(&self, _: &mut F) -> bool {
 349                     false
 350                 }
 351             }
 352         )+
 353     }
 354 }
 355
 356 CopyImpls! { (), hir::Unsafety, abi::Abi, ty::RegionParameterDef }
 357
 358 impl<'tcx, T:TypeFoldable<'tcx>, U:TypeFoldable<'tcx>> TypeFoldable<'tcx> for (T, U) {
 359     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> (T, U) {
 360         (self.0.fold_with(folder), self.1.fold_with(folder))
 361     }
 362
 363     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 364         self.0.visit_with(visitor) || self.1.visit_with(visitor)
 365     }
 366 }
 367
 368 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Option<T> {
 369     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 370         self.as_ref().map(|t| t.fold_with(folder))
 371     }
 372
 373     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 374         self.iter().any(|t| t.visit_with(visitor))
 375     }
 376 }
 377
 378 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Rc<T> {
 379     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 380         Rc::new((**self).fold_with(folder))
 381     }
 382
 383     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 384         (**self).visit_with(visitor)
 385     }
 386 }
 387
 388 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Box<T> {
 389     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 390         let content: T = (**self).fold_with(folder);
 391         box content
 392     }
 393
 394     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 395         (**self).visit_with(visitor)
 396     }
 397 }
 398
 399 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Vec<T> {
 400     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 401         self.iter().map(|t| t.fold_with(folder)).collect()
 402     }
 403
 404     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 405         self.iter().any(|t| t.visit_with(visitor))
 406     }
 407 }
 408
 409 impl<'tcx, T:TypeFoldable<'tcx>> TypeFoldable<'tcx> for ty::Binder<T> {
 410     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 411         ty::Binder(self.0.fold_with(folder))
 412     }
 413
 414     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 415         folder.fold_binder(self)
 416     }
 417
 418     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 419         self.0.visit_with(visitor)
 420     }
 421
 422     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 423         visitor.visit_binder(self)
 424     }
 425 }
 426
 427 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::Slice<ty::ExistentialPredicate<'tcx>> {
 428     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 429         let v = self.iter().map(|p| p.fold_with(folder)).collect::<AccumulateVec<[_; 8]>>();
 430         folder.tcx().intern_existential_predicates(&v)
 431     }
 432
 433     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 434         self.iter().any(|p| p.visit_with(visitor))
 435     }
 436 }
 437
 438 impl<'tcx> TypeFoldable<'tcx> for ty::ExistentialPredicate<'tcx> {
 439     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self  {
 440         use ty::ExistentialPredicate::*;
 441         match *self {
 442             Trait(ref tr) => Trait(tr.fold_with(folder)),
 443             Projection(ref p) => Projection(p.fold_with(folder)),
 444             AutoTrait(did) => AutoTrait(did),
 445         }
 446     }
 447
 448     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 449         match *self {
 450             ty::ExistentialPredicate::Trait(ref tr) => tr.visit_with(visitor),
 451             ty::ExistentialPredicate::Projection(ref p) => p.visit_with(visitor),
 452             ty::ExistentialPredicate::AutoTrait(_) => false,
 453         }
 454     }
 455 }
 456
 457 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::Slice<Ty<'tcx>> {
 458     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 459         let v = self.iter().map(|t| t.fold_with(folder)).collect::<AccumulateVec<[_; 8]>>();
 460         folder.tcx().intern_type_list(&v)
 461     }
 462
 463     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 464         self.iter().any(|t| t.visit_with(visitor))
 465     }
 466 }
 467
 468 impl<'tcx> TypeFoldable<'tcx> for Ty<'tcx> {
 469     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 470         let sty = match self.sty {
 471             ty::TyRawPtr(tm) => ty::TyRawPtr(tm.fold_with(folder)),
 472             ty::TyArray(typ, sz) => ty::TyArray(typ.fold_with(folder), sz),
 473             ty::TySlice(typ) => ty::TySlice(typ.fold_with(folder)),
 474             ty::TyAdt(tid, substs) => ty::TyAdt(tid, substs.fold_with(folder)),
 475             ty::TyDynamic(ref trait_ty, ref region) =>
 476                 ty::TyDynamic(trait_ty.fold_with(folder), region.fold_with(folder)),
 477             ty::TyTuple(ts) => ty::TyTuple(ts.fold_with(folder)),
 478             ty::TyFnDef(def_id, substs, f) => {
 479                 ty::TyFnDef(def_id,
 480                             substs.fold_with(folder),
 481                             f.fold_with(folder))
 482             }
 483             ty::TyFnPtr(f) => ty::TyFnPtr(f.fold_with(folder)),
 484             ty::TyRef(ref r, tm) => {
 485                 ty::TyRef(r.fold_with(folder), tm.fold_with(folder))
 486             }
 487             ty::TyClosure(did, substs) => ty::TyClosure(did, substs.fold_with(folder)),
 488             ty::TyProjection(ref data) => ty::TyProjection(data.fold_with(folder)),
 489             ty::TyAnon(did, substs) => ty::TyAnon(did, substs.fold_with(folder)),
 490             ty::TyBool | ty::TyChar | ty::TyStr | ty::TyInt(_) |
 491             ty::TyUint(_) | ty::TyFloat(_) | ty::TyError | ty::TyInfer(_) |
 492             ty::TyParam(..) | ty::TyNever => return self
 493         };
 494
 495         if self.sty == sty {
 496             self
 497         } else {
 498             folder.tcx().mk_ty(sty)
 499         }
 500     }
 501
 502     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 503         folder.fold_ty(*self)
 504     }
 505
 506     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 507         match self.sty {
 508             ty::TyRawPtr(ref tm) => tm.visit_with(visitor),
 509             ty::TyArray(typ, _sz) => typ.visit_with(visitor),
 510             ty::TySlice(typ) => typ.visit_with(visitor),
 511             ty::TyAdt(_, substs) => substs.visit_with(visitor),
 512             ty::TyDynamic(ref trait_ty, ref reg) =>
 513                 trait_ty.visit_with(visitor) || reg.visit_with(visitor),
 514             ty::TyTuple(ts) => ts.visit_with(visitor),
 515             ty::TyFnDef(_, substs, ref f) => {
 516                 substs.visit_with(visitor) || f.visit_with(visitor)
 517             }
 518             ty::TyFnPtr(ref f) => f.visit_with(visitor),
 519             ty::TyRef(r, ref tm) => r.visit_with(visitor) || tm.visit_with(visitor),
 520             ty::TyClosure(_did, ref substs) => substs.visit_with(visitor),
 521             ty::TyProjection(ref data) => data.visit_with(visitor),
 522             ty::TyAnon(_, ref substs) => substs.visit_with(visitor),
 523             ty::TyBool | ty::TyChar | ty::TyStr | ty::TyInt(_) |
 524             ty::TyUint(_) | ty::TyFloat(_) | ty::TyError | ty::TyInfer(_) |
 525             ty::TyParam(..) | ty::TyNever => false,
 526         }
 527     }
 528
 529     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 530         visitor.visit_ty(self)
 531     }
 532 }
 533
 534 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::BareFnTy<'tcx> {
 535     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 536         let fty = ty::BareFnTy {
 537             sig: self.sig.fold_with(folder),
 538             abi: self.abi,
 539             unsafety: self.unsafety
 540         };
 541         folder.tcx().mk_bare_fn(fty)
 542     }
 543
 544     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 545         folder.fold_bare_fn_ty(self)
 546     }
 547
 548     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 549         self.sig.visit_with(visitor)
 550     }
 551 }
 552
 553 impl<'tcx> TypeFoldable<'tcx> for ty::ClosureTy<'tcx> {
 554     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 555        ty::ClosureTy {
 556             sig: self.sig.fold_with(folder),
 557             unsafety: self.unsafety,
 558             abi: self.abi,
 559         }
 560     }
 561
 562     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 563         folder.fold_closure_ty(self)
 564     }
 565
 566     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 567         self.sig.visit_with(visitor)
 568     }
 569 }
 570
 571 impl<'tcx> TypeFoldable<'tcx> for ty::TypeAndMut<'tcx> {
 572     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 573         ty::TypeAndMut { ty: self.ty.fold_with(folder), mutbl: self.mutbl }
 574     }
 575
 576     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 577         folder.fold_mt(self)
 578     }
 579
 580     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 581         self.ty.visit_with(visitor)
 582     }
 583 }
 584
 585 impl<'tcx> TypeFoldable<'tcx> for ty::FnSig<'tcx> {
 586     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 587         let inputs_and_output = self.inputs_and_output.fold_with(folder);
 588         ty::FnSig {
 589             inputs_and_output: folder.tcx().intern_type_list(&inputs_and_output),
 590             variadic: self.variadic,
 591         }
 592     }
 593
 594     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 595         folder.fold_fn_sig(self)
 596     }
 597
 598     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 599         self.inputs().iter().any(|i| i.visit_with(visitor)) ||
 600         self.output().visit_with(visitor)
 601     }
 602 }
 603
 604 impl<'tcx> TypeFoldable<'tcx> for ty::TraitRef<'tcx> {
 605     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 606         ty::TraitRef {
 607             def_id: self.def_id,
 608             substs: self.substs.fold_with(folder),
 609         }
 610     }
 611
 612     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 613         self.substs.visit_with(visitor)
 614     }
 615
 616     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 617         visitor.visit_trait_ref(*self)
 618     }
 619 }
 620
 621 impl<'tcx> TypeFoldable<'tcx> for ty::ExistentialTraitRef<'tcx> {
 622     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 623         ty::ExistentialTraitRef {
 624             def_id: self.def_id,
 625             substs: self.substs.fold_with(folder),
 626         }
 627     }
 628
 629     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 630         self.substs.visit_with(visitor)
 631     }
 632 }
 633
 634 impl<'tcx> TypeFoldable<'tcx> for ty::ImplHeader<'tcx> {
 635     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 636         ty::ImplHeader {
 637             impl_def_id: self.impl_def_id,
 638             self_ty: self.self_ty.fold_with(folder),
 639             trait_ref: self.trait_ref.map(|t| t.fold_with(folder)),
 640             predicates: self.predicates.iter().map(|p| p.fold_with(folder)).collect(),
 641         }
 642     }
 643
 644     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 645         folder.fold_impl_header(self)
 646     }
 647
 648     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 649         self.self_ty.visit_with(visitor) ||
 650             self.trait_ref.map(|r| r.visit_with(visitor)).unwrap_or(false) ||
 651             self.predicates.iter().any(|p| p.visit_with(visitor))
 652     }
 653 }
 654
 655 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::Region {
 656     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, _folder: &mut F) -> Self {
 657         *self
 658     }
 659
 660     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 661         folder.fold_region(*self)
 662     }
 663
 664     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _visitor: &mut V) -> bool {
 665         false
 666     }
 667
 668     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 669         visitor.visit_region(*self)
 670     }
 671 }
 672
 673 impl<'tcx> TypeFoldable<'tcx> for ty::ClosureSubsts<'tcx> {
 674     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 675         ty::ClosureSubsts {
 676             substs: self.substs.fold_with(folder),
 677         }
 678     }
 679
 680     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 681         self.substs.visit_with(visitor)
 682     }
 683 }
 684
 685 impl<'tcx> TypeFoldable<'tcx> for ty::ItemSubsts<'tcx> {
 686     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 687         ty::ItemSubsts {
 688             substs: self.substs.fold_with(folder),
 689         }
 690     }
 691
 692     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 693         self.substs.visit_with(visitor)
 694     }
 695 }
 696
 697 impl<'tcx> TypeFoldable<'tcx> for ty::adjustment::AutoBorrow<'tcx> {
 698     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 699         match *self {
 700             ty::adjustment::AutoBorrow::Ref(ref r, m) => {
 701                 ty::adjustment::AutoBorrow::Ref(r.fold_with(folder), m)
 702             }
 703             ty::adjustment::AutoBorrow::RawPtr(m) => ty::adjustment::AutoBorrow::RawPtr(m)
 704         }
 705     }
 706
 707     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 708         folder.fold_autoref(self)
 709     }
 710
 711     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 712         match *self {
 713             ty::adjustment::AutoBorrow::Ref(r, _m) => r.visit_with(visitor),
 714             ty::adjustment::AutoBorrow::RawPtr(_m) => false,
 715         }
 716     }
 717 }
 718
 719 impl<'tcx> TypeFoldable<'tcx> for ty::TypeParameterDef<'tcx> {
 720     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 721         ty::TypeParameterDef {
 722             name: self.name,
 723             def_id: self.def_id,
 724             index: self.index,
 725             default: self.default.fold_with(folder),
 726             default_def_id: self.default_def_id,
 727             pure_wrt_drop: self.pure_wrt_drop,
 728         }
 729     }
 730
 731     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 732         self.default.visit_with(visitor)
 733     }
 734 }
 735
 736 impl<'tcx> TypeFoldable<'tcx> for ty::Generics<'tcx> {
 737     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 738         ty::Generics {
 739             parent: self.parent,
 740             parent_regions: self.parent_regions,
 741             parent_types: self.parent_types,
 742             regions: self.regions.fold_with(folder),
 743             types: self.types.fold_with(folder),
 744             has_self: self.has_self,
 745         }
 746     }
 747
 748     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 749         self.regions.visit_with(visitor) || self.types.visit_with(visitor)
 750     }
 751 }
 752
 753 impl<'tcx> TypeFoldable<'tcx> for ty::GenericPredicates<'tcx> {
 754     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 755         ty::GenericPredicates {
 756             parent: self.parent,
 757             predicates: self.predicates.fold_with(folder),
 758         }
 759     }
 760
 761     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 762         self.predicates.visit_with(visitor)
 763     }
 764 }
 765
 766 impl<'tcx> TypeFoldable<'tcx> for ty::Predicate<'tcx> {
 767     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 768         match *self {
 769             ty::Predicate::Trait(ref a) =>
 770                 ty::Predicate::Trait(a.fold_with(folder)),
 771             ty::Predicate::Equate(ref binder) =>
 772                 ty::Predicate::Equate(binder.fold_with(folder)),
 773             ty::Predicate::RegionOutlives(ref binder) =>
 774                 ty::Predicate::RegionOutlives(binder.fold_with(folder)),
 775             ty::Predicate::TypeOutlives(ref binder) =>
 776                 ty::Predicate::TypeOutlives(binder.fold_with(folder)),
 777             ty::Predicate::Projection(ref binder) =>
 778                 ty::Predicate::Projection(binder.fold_with(folder)),
 779             ty::Predicate::WellFormed(data) =>
 780                 ty::Predicate::WellFormed(data.fold_with(folder)),
 781             ty::Predicate::ClosureKind(closure_def_id, kind) =>
 782                 ty::Predicate::ClosureKind(closure_def_id, kind),
 783             ty::Predicate::ObjectSafe(trait_def_id) =>
 784                 ty::Predicate::ObjectSafe(trait_def_id),
 785         }
 786     }
 787
 788     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 789         match *self {
 790             ty::Predicate::Trait(ref a) => a.visit_with(visitor),
 791             ty::Predicate::Equate(ref binder) => binder.visit_with(visitor),
 792             ty::Predicate::RegionOutlives(ref binder) => binder.visit_with(visitor),
 793             ty::Predicate::TypeOutlives(ref binder) => binder.visit_with(visitor),
 794             ty::Predicate::Projection(ref binder) => binder.visit_with(visitor),
 795             ty::Predicate::WellFormed(data) => data.visit_with(visitor),
 796             ty::Predicate::ClosureKind(_closure_def_id, _kind) => false,
 797             ty::Predicate::ObjectSafe(_trait_def_id) => false,
 798         }
 799     }
 800 }
 801
 802 impl<'tcx> TypeFoldable<'tcx> for ty::ProjectionPredicate<'tcx> {
 803     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 804         ty::ProjectionPredicate {
 805             projection_ty: self.projection_ty.fold_with(folder),
 806             ty: self.ty.fold_with(folder),
 807         }
 808     }
 809
 810     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 811         self.projection_ty.visit_with(visitor) || self.ty.visit_with(visitor)
 812     }
 813 }
 814
 815 impl<'tcx> TypeFoldable<'tcx> for ty::ExistentialProjection<'tcx> {
 816     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 817         ty::ExistentialProjection {
 818             trait_ref: self.trait_ref.fold_with(folder),
 819             item_name: self.item_name,
 820             ty: self.ty.fold_with(folder),
 821         }
 822     }
 823
 824     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 825         self.trait_ref.visit_with(visitor) || self.ty.visit_with(visitor)
 826     }
 827 }
 828
 829 impl<'tcx> TypeFoldable<'tcx> for ty::ProjectionTy<'tcx> {
 830     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 831         ty::ProjectionTy {
 832             trait_ref: self.trait_ref.fold_with(folder),
 833             item_name: self.item_name,
 834         }
 835     }
 836
 837     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 838         self.trait_ref.visit_with(visitor)
 839     }
 840 }
 841
 842 impl<'tcx> TypeFoldable<'tcx> for ty::InstantiatedPredicates<'tcx> {
 843     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 844         ty::InstantiatedPredicates {
 845             predicates: self.predicates.fold_with(folder),
 846         }
 847     }
 848
 849     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 850         self.predicates.visit_with(visitor)
 851     }
 852 }
 853
 854 impl<'tcx> TypeFoldable<'tcx> for ty::EquatePredicate<'tcx> {
 855     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 856         ty::EquatePredicate(self.0.fold_with(folder),
 857                             self.1.fold_with(folder))
 858     }
 859
 860     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 861         self.0.visit_with(visitor) || self.1.visit_with(visitor)
 862     }
 863 }
 864
 865 impl<'tcx> TypeFoldable<'tcx> for ty::TraitPredicate<'tcx> {
 866     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 867         ty::TraitPredicate {
 868             trait_ref: self.trait_ref.fold_with(folder)
 869         }
 870     }
 871
 872     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 873         self.trait_ref.visit_with(visitor)
 874     }
 875 }
 876
 877 impl<'tcx,T,U> TypeFoldable<'tcx> for ty::OutlivesPredicate<T,U>
 878     where T : TypeFoldable<'tcx>,
 879           U : TypeFoldable<'tcx>,
 880 {
 881     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 882         ty::OutlivesPredicate(self.0.fold_with(folder),
 883                               self.1.fold_with(folder))
 884     }
 885
 886     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 887         self.0.visit_with(visitor) || self.1.visit_with(visitor)
 888     }
 889 }
 890
 891 impl<'tcx> TypeFoldable<'tcx> for ty::ClosureUpvar<'tcx> {
 892     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 893         ty::ClosureUpvar {
 894             def: self.def,
 895             span: self.span,
 896             ty: self.ty.fold_with(folder),
 897         }
 898     }
 899
 900     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 901         self.ty.visit_with(visitor)
 902     }
 903 }
 904
 905 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for ty::error::ExpectedFound<T> {
 906     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 907         ty::error::ExpectedFound {
 908             expected: self.expected.fold_with(folder),
 909             found: self.found.fold_with(folder),
 910         }
 911     }
 912
 913     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 914         self.expected.visit_with(visitor) || self.found.visit_with(visitor)
 915     }
 916 }