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