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.
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.
11 pub use self::ImplOrTraitItemId::*;
12 pub use self::ClosureKind::*;
13 pub use self::Variance::*;
14 pub use self::DtorKind::*;
15 pub use self::ExplicitSelfCategory::*;
16 pub use self::ImplOrTraitItemContainer::*;
17 pub use self::BorrowKind::*;
18 pub use self::ImplOrTraitItem::*;
19 pub use self::IntVarValue::*;
20 pub use self::LvaluePreference::*;
22 use front::map as ast_map;
23 use front::map::LinkedPath;
24 use metadata::csearch;
26 use middle::def::{self, ExportMap};
27 use middle::def_id::{DefId, LOCAL_CRATE};
28 use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
29 use middle::subst::{self, ParamSpace, Subst, Substs, VecPerParamSpace};
32 use middle::ty::fold::TypeFolder;
33 use middle::ty::walk::TypeWalker;
34 use util::common::memoized;
35 use util::nodemap::{NodeMap, NodeSet, DefIdMap};
36 use util::nodemap::FnvHashMap;
38 use std::borrow::{Borrow, Cow};
39 use std::cell::{Cell, RefCell};
40 use std::hash::{Hash, Hasher};
44 use std::vec::IntoIter;
45 use std::collections::{HashMap, HashSet};
46 use syntax::ast::{self, CrateNum, Name, NodeId};
47 use syntax::codemap::Span;
48 use syntax::parse::token::{InternedString, special_idents};
51 use rustc_front::hir::{ItemImpl, ItemTrait};
52 use rustc_front::hir::{MutImmutable, MutMutable, Visibility};
53 use rustc_front::attr::{self, AttrMetaMethods};
55 pub use self::sty::{Binder, DebruijnIndex};
56 pub use self::sty::{BuiltinBound, BuiltinBounds, ExistentialBounds};
57 pub use self::sty::{BareFnTy, FnSig, PolyFnSig, FnOutput, PolyFnOutput};
58 pub use self::sty::{ClosureTy, InferTy, ParamTy, ProjectionTy, TraitTy};
59 pub use self::sty::{ClosureSubsts, TypeAndMut};
60 pub use self::sty::{TraitRef, TypeVariants, PolyTraitRef};
61 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
62 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid, SkolemizedRegionVid};
63 pub use self::sty::BoundRegion::*;
64 pub use self::sty::FnOutput::*;
65 pub use self::sty::InferTy::*;
66 pub use self::sty::Region::*;
67 pub use self::sty::TypeVariants::*;
69 pub use self::sty::BuiltinBound::Send as BoundSend;
70 pub use self::sty::BuiltinBound::Sized as BoundSized;
71 pub use self::sty::BuiltinBound::Copy as BoundCopy;
72 pub use self::sty::BuiltinBound::Sync as BoundSync;
74 pub use self::contents::TypeContents;
75 pub use self::context::{ctxt, tls};
76 pub use self::context::{CtxtArenas, Lift, Tables};
98 pub const INITIAL_DISCRIMINANT_VALUE: Disr = 0;
102 /// The complete set of all analyses described in this module. This is
103 /// produced by the driver and fed to trans and later passes.
104 pub struct CrateAnalysis {
105 pub export_map: ExportMap,
106 pub exported_items: middle::privacy::ExportedItems,
107 pub public_items: middle::privacy::PublicItems,
108 pub reachable: NodeSet,
110 pub glob_map: Option<GlobMap>,
114 #[derive(Copy, Clone)]
121 pub fn is_present(&self) -> bool {
123 TraitDtor(..) => true,
128 pub fn has_drop_flag(&self) -> bool {
131 &TraitDtor(flag) => flag
136 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
137 pub enum ImplOrTraitItemContainer {
138 TraitContainer(DefId),
139 ImplContainer(DefId),
142 impl ImplOrTraitItemContainer {
143 pub fn id(&self) -> DefId {
145 TraitContainer(id) => id,
146 ImplContainer(id) => id,
152 pub enum ImplOrTraitItem<'tcx> {
153 ConstTraitItem(Rc<AssociatedConst<'tcx>>),
154 MethodTraitItem(Rc<Method<'tcx>>),
155 TypeTraitItem(Rc<AssociatedType<'tcx>>),
158 impl<'tcx> ImplOrTraitItem<'tcx> {
159 fn id(&self) -> ImplOrTraitItemId {
161 ConstTraitItem(ref associated_const) => {
162 ConstTraitItemId(associated_const.def_id)
164 MethodTraitItem(ref method) => MethodTraitItemId(method.def_id),
165 TypeTraitItem(ref associated_type) => {
166 TypeTraitItemId(associated_type.def_id)
171 pub fn def_id(&self) -> DefId {
173 ConstTraitItem(ref associated_const) => associated_const.def_id,
174 MethodTraitItem(ref method) => method.def_id,
175 TypeTraitItem(ref associated_type) => associated_type.def_id,
179 pub fn name(&self) -> Name {
181 ConstTraitItem(ref associated_const) => associated_const.name,
182 MethodTraitItem(ref method) => method.name,
183 TypeTraitItem(ref associated_type) => associated_type.name,
187 pub fn vis(&self) -> hir::Visibility {
189 ConstTraitItem(ref associated_const) => associated_const.vis,
190 MethodTraitItem(ref method) => method.vis,
191 TypeTraitItem(ref associated_type) => associated_type.vis,
195 pub fn container(&self) -> ImplOrTraitItemContainer {
197 ConstTraitItem(ref associated_const) => associated_const.container,
198 MethodTraitItem(ref method) => method.container,
199 TypeTraitItem(ref associated_type) => associated_type.container,
203 pub fn as_opt_method(&self) -> Option<Rc<Method<'tcx>>> {
205 MethodTraitItem(ref m) => Some((*m).clone()),
211 #[derive(Clone, Copy, Debug)]
212 pub enum ImplOrTraitItemId {
213 ConstTraitItemId(DefId),
214 MethodTraitItemId(DefId),
215 TypeTraitItemId(DefId),
218 impl ImplOrTraitItemId {
219 pub fn def_id(&self) -> DefId {
221 ConstTraitItemId(def_id) => def_id,
222 MethodTraitItemId(def_id) => def_id,
223 TypeTraitItemId(def_id) => def_id,
228 #[derive(Clone, Debug)]
229 pub struct Method<'tcx> {
231 pub generics: Generics<'tcx>,
232 pub predicates: GenericPredicates<'tcx>,
233 pub fty: BareFnTy<'tcx>,
234 pub explicit_self: ExplicitSelfCategory,
235 pub vis: hir::Visibility,
237 pub container: ImplOrTraitItemContainer,
239 // If this method is provided, we need to know where it came from
240 pub provided_source: Option<DefId>
243 impl<'tcx> Method<'tcx> {
244 pub fn new(name: Name,
245 generics: ty::Generics<'tcx>,
246 predicates: GenericPredicates<'tcx>,
248 explicit_self: ExplicitSelfCategory,
249 vis: hir::Visibility,
251 container: ImplOrTraitItemContainer,
252 provided_source: Option<DefId>)
257 predicates: predicates,
259 explicit_self: explicit_self,
262 container: container,
263 provided_source: provided_source
267 pub fn container_id(&self) -> DefId {
268 match self.container {
269 TraitContainer(id) => id,
270 ImplContainer(id) => id,
275 #[derive(Clone, Copy, Debug)]
276 pub struct AssociatedConst<'tcx> {
279 pub vis: hir::Visibility,
281 pub container: ImplOrTraitItemContainer,
282 pub default: Option<DefId>,
285 #[derive(Clone, Copy, Debug)]
286 pub struct AssociatedType<'tcx> {
288 pub ty: Option<Ty<'tcx>>,
289 pub vis: hir::Visibility,
291 pub container: ImplOrTraitItemContainer,
294 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable)]
295 pub struct ItemVariances {
296 pub types: VecPerParamSpace<Variance>,
297 pub regions: VecPerParamSpace<Variance>,
300 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
302 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
303 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
304 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
305 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
308 #[derive(Clone, Copy, Debug)]
309 pub struct MethodCallee<'tcx> {
310 /// Impl method ID, for inherent methods, or trait method ID, otherwise.
313 pub substs: &'tcx subst::Substs<'tcx>
316 /// With method calls, we store some extra information in
317 /// side tables (i.e method_map). We use
318 /// MethodCall as a key to index into these tables instead of
319 /// just directly using the expression's NodeId. The reason
320 /// for this being that we may apply adjustments (coercions)
321 /// with the resulting expression also needing to use the
322 /// side tables. The problem with this is that we don't
323 /// assign a separate NodeId to this new expression
324 /// and so it would clash with the base expression if both
325 /// needed to add to the side tables. Thus to disambiguate
326 /// we also keep track of whether there's an adjustment in
328 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
329 pub struct MethodCall {
335 pub fn expr(id: NodeId) -> MethodCall {
342 pub fn autoderef(expr_id: NodeId, autoderef: u32) -> MethodCall {
345 autoderef: 1 + autoderef
350 // maps from an expression id that corresponds to a method call to the details
351 // of the method to be invoked
352 pub type MethodMap<'tcx> = FnvHashMap<MethodCall, MethodCallee<'tcx>>;
354 // Contains information needed to resolve types and (in the future) look up
355 // the types of AST nodes.
356 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
357 pub struct CReaderCacheKey {
363 /// A restriction that certain types must be the same size. The use of
364 /// `transmute` gives rise to these restrictions. These generally
365 /// cannot be checked until trans; therefore, each call to `transmute`
366 /// will push one or more such restriction into the
367 /// `transmute_restrictions` vector during `intrinsicck`. They are
368 /// then checked during `trans` by the fn `check_intrinsics`.
369 #[derive(Copy, Clone)]
370 pub struct TransmuteRestriction<'tcx> {
371 /// The span whence the restriction comes.
374 /// The type being transmuted from.
375 pub original_from: Ty<'tcx>,
377 /// The type being transmuted to.
378 pub original_to: Ty<'tcx>,
380 /// The type being transmuted from, with all type parameters
381 /// substituted for an arbitrary representative. Not to be shown
383 pub substituted_from: Ty<'tcx>,
385 /// The type being transmuted to, with all type parameters
386 /// substituted for an arbitrary representative. Not to be shown
388 pub substituted_to: Ty<'tcx>,
390 /// NodeId of the transmute intrinsic.
394 /// Describes the fragment-state associated with a NodeId.
396 /// Currently only unfragmented paths have entries in the table,
397 /// but longer-term this enum is expected to expand to also
398 /// include data for fragmented paths.
399 #[derive(Copy, Clone, Debug)]
400 pub enum FragmentInfo {
401 Moved { var: NodeId, move_expr: NodeId },
402 Assigned { var: NodeId, assign_expr: NodeId, assignee_id: NodeId },
405 // Flags that we track on types. These flags are propagated upwards
406 // through the type during type construction, so that we can quickly
407 // check whether the type has various kinds of types in it without
408 // recursing over the type itself.
410 flags TypeFlags: u32 {
411 const HAS_PARAMS = 1 << 0,
412 const HAS_SELF = 1 << 1,
413 const HAS_TY_INFER = 1 << 2,
414 const HAS_RE_INFER = 1 << 3,
415 const HAS_RE_EARLY_BOUND = 1 << 4,
416 const HAS_FREE_REGIONS = 1 << 5,
417 const HAS_TY_ERR = 1 << 6,
418 const HAS_PROJECTION = 1 << 7,
419 const HAS_TY_CLOSURE = 1 << 8,
421 // true if there are "names" of types and regions and so forth
422 // that are local to a particular fn
423 const HAS_LOCAL_NAMES = 1 << 9,
425 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
426 TypeFlags::HAS_SELF.bits |
427 TypeFlags::HAS_RE_EARLY_BOUND.bits,
429 // Flags representing the nominal content of a type,
430 // computed by FlagsComputation. If you add a new nominal
431 // flag, it should be added here too.
432 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
433 TypeFlags::HAS_SELF.bits |
434 TypeFlags::HAS_TY_INFER.bits |
435 TypeFlags::HAS_RE_INFER.bits |
436 TypeFlags::HAS_RE_EARLY_BOUND.bits |
437 TypeFlags::HAS_FREE_REGIONS.bits |
438 TypeFlags::HAS_TY_ERR.bits |
439 TypeFlags::HAS_PROJECTION.bits |
440 TypeFlags::HAS_TY_CLOSURE.bits |
441 TypeFlags::HAS_LOCAL_NAMES.bits,
443 // Caches for type_is_sized, type_moves_by_default
444 const SIZEDNESS_CACHED = 1 << 16,
445 const IS_SIZED = 1 << 17,
446 const MOVENESS_CACHED = 1 << 18,
447 const MOVES_BY_DEFAULT = 1 << 19,
451 pub struct TyS<'tcx> {
452 pub sty: TypeVariants<'tcx>,
453 pub flags: Cell<TypeFlags>,
455 // the maximal depth of any bound regions appearing in this type.
459 impl<'tcx> PartialEq for TyS<'tcx> {
461 fn eq(&self, other: &TyS<'tcx>) -> bool {
462 // (self as *const _) == (other as *const _)
463 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
466 impl<'tcx> Eq for TyS<'tcx> {}
468 impl<'tcx> Hash for TyS<'tcx> {
469 fn hash<H: Hasher>(&self, s: &mut H) {
470 (self as *const TyS).hash(s)
474 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
476 /// Upvars do not get their own node-id. Instead, we use the pair of
477 /// the original var id (that is, the root variable that is referenced
478 /// by the upvar) and the id of the closure expression.
479 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
482 pub closure_expr_id: NodeId,
485 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
486 pub enum BorrowKind {
487 /// Data must be immutable and is aliasable.
490 /// Data must be immutable but not aliasable. This kind of borrow
491 /// cannot currently be expressed by the user and is used only in
492 /// implicit closure bindings. It is needed when you the closure
493 /// is borrowing or mutating a mutable referent, e.g.:
495 /// let x: &mut isize = ...;
496 /// let y = || *x += 5;
498 /// If we were to try to translate this closure into a more explicit
499 /// form, we'd encounter an error with the code as written:
501 /// struct Env { x: & &mut isize }
502 /// let x: &mut isize = ...;
503 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
504 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
506 /// This is then illegal because you cannot mutate a `&mut` found
507 /// in an aliasable location. To solve, you'd have to translate with
508 /// an `&mut` borrow:
510 /// struct Env { x: & &mut isize }
511 /// let x: &mut isize = ...;
512 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
513 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
515 /// Now the assignment to `**env.x` is legal, but creating a
516 /// mutable pointer to `x` is not because `x` is not mutable. We
517 /// could fix this by declaring `x` as `let mut x`. This is ok in
518 /// user code, if awkward, but extra weird for closures, since the
519 /// borrow is hidden.
521 /// So we introduce a "unique imm" borrow -- the referent is
522 /// immutable, but not aliasable. This solves the problem. For
523 /// simplicity, we don't give users the way to express this
524 /// borrow, it's just used when translating closures.
527 /// Data is mutable and not aliasable.
531 /// Information describing the capture of an upvar. This is computed
532 /// during `typeck`, specifically by `regionck`.
533 #[derive(PartialEq, Clone, Debug, Copy)]
534 pub enum UpvarCapture {
535 /// Upvar is captured by value. This is always true when the
536 /// closure is labeled `move`, but can also be true in other cases
537 /// depending on inference.
540 /// Upvar is captured by reference.
544 #[derive(PartialEq, Clone, Copy)]
545 pub struct UpvarBorrow {
546 /// The kind of borrow: by-ref upvars have access to shared
547 /// immutable borrows, which are not part of the normal language
549 pub kind: BorrowKind,
551 /// Region of the resulting reference.
552 pub region: ty::Region,
555 pub type UpvarCaptureMap = FnvHashMap<UpvarId, UpvarCapture>;
557 #[derive(Copy, Clone)]
558 pub struct ClosureUpvar<'tcx> {
564 #[derive(Clone, Copy, PartialEq)]
565 pub enum IntVarValue {
567 UintType(hir::UintTy),
570 /// Default region to use for the bound of objects that are
571 /// supplied as the value for this type parameter. This is derived
572 /// from `T:'a` annotations appearing in the type definition. If
573 /// this is `None`, then the default is inherited from the
574 /// surrounding context. See RFC #599 for details.
575 #[derive(Copy, Clone)]
576 pub enum ObjectLifetimeDefault {
577 /// Require an explicit annotation. Occurs when multiple
578 /// `T:'a` constraints are found.
581 /// Use the base default, typically 'static, but in a fn body it is a fresh variable
584 /// Use the given region as the default.
589 pub struct TypeParameterDef<'tcx> {
592 pub space: subst::ParamSpace,
594 pub default_def_id: DefId, // for use in error reporing about defaults
595 pub default: Option<Ty<'tcx>>,
596 pub object_lifetime_default: ObjectLifetimeDefault,
600 pub struct RegionParameterDef {
603 pub space: subst::ParamSpace,
605 pub bounds: Vec<ty::Region>,
608 impl RegionParameterDef {
609 pub fn to_early_bound_region(&self) -> ty::Region {
610 ty::ReEarlyBound(ty::EarlyBoundRegion {
611 param_id: self.def_id.node,
617 pub fn to_bound_region(&self) -> ty::BoundRegion {
618 ty::BoundRegion::BrNamed(self.def_id, self.name)
622 /// Information about the formal type/lifetime parameters associated
623 /// with an item or method. Analogous to hir::Generics.
624 #[derive(Clone, Debug)]
625 pub struct Generics<'tcx> {
626 pub types: VecPerParamSpace<TypeParameterDef<'tcx>>,
627 pub regions: VecPerParamSpace<RegionParameterDef>,
630 impl<'tcx> Generics<'tcx> {
631 pub fn empty() -> Generics<'tcx> {
633 types: VecPerParamSpace::empty(),
634 regions: VecPerParamSpace::empty(),
638 pub fn is_empty(&self) -> bool {
639 self.types.is_empty() && self.regions.is_empty()
642 pub fn has_type_params(&self, space: subst::ParamSpace) -> bool {
643 !self.types.is_empty_in(space)
646 pub fn has_region_params(&self, space: subst::ParamSpace) -> bool {
647 !self.regions.is_empty_in(space)
651 /// Bounds on generics.
653 pub struct GenericPredicates<'tcx> {
654 pub predicates: VecPerParamSpace<Predicate<'tcx>>,
657 impl<'tcx> GenericPredicates<'tcx> {
658 pub fn empty() -> GenericPredicates<'tcx> {
660 predicates: VecPerParamSpace::empty(),
664 pub fn instantiate(&self, tcx: &ctxt<'tcx>, substs: &Substs<'tcx>)
665 -> InstantiatedPredicates<'tcx> {
666 InstantiatedPredicates {
667 predicates: self.predicates.subst(tcx, substs),
671 pub fn instantiate_supertrait(&self,
673 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
674 -> InstantiatedPredicates<'tcx>
676 InstantiatedPredicates {
677 predicates: self.predicates.map(|pred| pred.subst_supertrait(tcx, poly_trait_ref))
682 #[derive(Clone, PartialEq, Eq, Hash)]
683 pub enum Predicate<'tcx> {
684 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
685 /// the `Self` type of the trait reference and `A`, `B`, and `C`
686 /// would be the parameters in the `TypeSpace`.
687 Trait(PolyTraitPredicate<'tcx>),
689 /// where `T1 == T2`.
690 Equate(PolyEquatePredicate<'tcx>),
693 RegionOutlives(PolyRegionOutlivesPredicate),
696 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
698 /// where <T as TraitRef>::Name == X, approximately.
699 /// See `ProjectionPredicate` struct for details.
700 Projection(PolyProjectionPredicate<'tcx>),
703 WellFormed(Ty<'tcx>),
705 /// trait must be object-safe
709 impl<'tcx> Predicate<'tcx> {
710 /// Performs a substitution suitable for going from a
711 /// poly-trait-ref to supertraits that must hold if that
712 /// poly-trait-ref holds. This is slightly different from a normal
713 /// substitution in terms of what happens with bound regions. See
714 /// lengthy comment below for details.
715 pub fn subst_supertrait(&self,
717 trait_ref: &ty::PolyTraitRef<'tcx>)
718 -> ty::Predicate<'tcx>
720 // The interaction between HRTB and supertraits is not entirely
721 // obvious. Let me walk you (and myself) through an example.
723 // Let's start with an easy case. Consider two traits:
725 // trait Foo<'a> : Bar<'a,'a> { }
726 // trait Bar<'b,'c> { }
728 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
729 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
730 // knew that `Foo<'x>` (for any 'x) then we also know that
731 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
732 // normal substitution.
734 // In terms of why this is sound, the idea is that whenever there
735 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
736 // holds. So if there is an impl of `T:Foo<'a>` that applies to
737 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
740 // Another example to be careful of is this:
742 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
743 // trait Bar1<'b,'c> { }
745 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
746 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
747 // reason is similar to the previous example: any impl of
748 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
749 // basically we would want to collapse the bound lifetimes from
750 // the input (`trait_ref`) and the supertraits.
752 // To achieve this in practice is fairly straightforward. Let's
753 // consider the more complicated scenario:
755 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
756 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
757 // where both `'x` and `'b` would have a DB index of 1.
758 // The substitution from the input trait-ref is therefore going to be
759 // `'a => 'x` (where `'x` has a DB index of 1).
760 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
761 // early-bound parameter and `'b' is a late-bound parameter with a
763 // - If we replace `'a` with `'x` from the input, it too will have
764 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
765 // just as we wanted.
767 // There is only one catch. If we just apply the substitution `'a
768 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
769 // adjust the DB index because we substituting into a binder (it
770 // tries to be so smart...) resulting in `for<'x> for<'b>
771 // Bar1<'x,'b>` (we have no syntax for this, so use your
772 // imagination). Basically the 'x will have DB index of 2 and 'b
773 // will have DB index of 1. Not quite what we want. So we apply
774 // the substitution to the *contents* of the trait reference,
775 // rather than the trait reference itself (put another way, the
776 // substitution code expects equal binding levels in the values
777 // from the substitution and the value being substituted into, and
778 // this trick achieves that).
780 let substs = &trait_ref.0.substs;
782 Predicate::Trait(ty::Binder(ref data)) =>
783 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
784 Predicate::Equate(ty::Binder(ref data)) =>
785 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
786 Predicate::RegionOutlives(ty::Binder(ref data)) =>
787 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
788 Predicate::TypeOutlives(ty::Binder(ref data)) =>
789 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
790 Predicate::Projection(ty::Binder(ref data)) =>
791 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
792 Predicate::WellFormed(data) =>
793 Predicate::WellFormed(data.subst(tcx, substs)),
794 Predicate::ObjectSafe(trait_def_id) =>
795 Predicate::ObjectSafe(trait_def_id),
800 #[derive(Clone, PartialEq, Eq, Hash)]
801 pub struct TraitPredicate<'tcx> {
802 pub trait_ref: TraitRef<'tcx>
804 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
806 impl<'tcx> TraitPredicate<'tcx> {
807 pub fn def_id(&self) -> DefId {
808 self.trait_ref.def_id
811 pub fn input_types(&self) -> &[Ty<'tcx>] {
812 self.trait_ref.substs.types.as_slice()
815 pub fn self_ty(&self) -> Ty<'tcx> {
816 self.trait_ref.self_ty()
820 impl<'tcx> PolyTraitPredicate<'tcx> {
821 pub fn def_id(&self) -> DefId {
826 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
827 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
828 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
830 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
831 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
832 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
833 pub type PolyRegionOutlivesPredicate = PolyOutlivesPredicate<ty::Region, ty::Region>;
834 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region>;
836 /// This kind of predicate has no *direct* correspondent in the
837 /// syntax, but it roughly corresponds to the syntactic forms:
839 /// 1. `T : TraitRef<..., Item=Type>`
840 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
842 /// In particular, form #1 is "desugared" to the combination of a
843 /// normal trait predicate (`T : TraitRef<...>`) and one of these
844 /// predicates. Form #2 is a broader form in that it also permits
845 /// equality between arbitrary types. Processing an instance of Form
846 /// #2 eventually yields one of these `ProjectionPredicate`
847 /// instances to normalize the LHS.
848 #[derive(Clone, PartialEq, Eq, Hash)]
849 pub struct ProjectionPredicate<'tcx> {
850 pub projection_ty: ProjectionTy<'tcx>,
854 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
856 impl<'tcx> PolyProjectionPredicate<'tcx> {
857 pub fn item_name(&self) -> Name {
858 self.0.projection_ty.item_name // safe to skip the binder to access a name
861 pub fn sort_key(&self) -> (DefId, Name) {
862 self.0.projection_ty.sort_key()
866 pub trait ToPolyTraitRef<'tcx> {
867 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
870 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
871 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
872 assert!(!self.has_escaping_regions());
873 ty::Binder(self.clone())
877 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
878 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
879 self.map_bound_ref(|trait_pred| trait_pred.trait_ref.clone())
883 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
884 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
885 // Note: unlike with TraitRef::to_poly_trait_ref(),
886 // self.0.trait_ref is permitted to have escaping regions.
887 // This is because here `self` has a `Binder` and so does our
888 // return value, so we are preserving the number of binding
890 ty::Binder(self.0.projection_ty.trait_ref.clone())
894 pub trait ToPredicate<'tcx> {
895 fn to_predicate(&self) -> Predicate<'tcx>;
898 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
899 fn to_predicate(&self) -> Predicate<'tcx> {
900 // we're about to add a binder, so let's check that we don't
901 // accidentally capture anything, or else that might be some
902 // weird debruijn accounting.
903 assert!(!self.has_escaping_regions());
905 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
906 trait_ref: self.clone()
911 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
912 fn to_predicate(&self) -> Predicate<'tcx> {
913 ty::Predicate::Trait(self.to_poly_trait_predicate())
917 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
918 fn to_predicate(&self) -> Predicate<'tcx> {
919 Predicate::Equate(self.clone())
923 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate {
924 fn to_predicate(&self) -> Predicate<'tcx> {
925 Predicate::RegionOutlives(self.clone())
929 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
930 fn to_predicate(&self) -> Predicate<'tcx> {
931 Predicate::TypeOutlives(self.clone())
935 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
936 fn to_predicate(&self) -> Predicate<'tcx> {
937 Predicate::Projection(self.clone())
941 impl<'tcx> Predicate<'tcx> {
942 /// Iterates over the types in this predicate. Note that in all
943 /// cases this is skipping over a binder, so late-bound regions
944 /// with depth 0 are bound by the predicate.
945 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
946 let vec: Vec<_> = match *self {
947 ty::Predicate::Trait(ref data) => {
948 data.0.trait_ref.substs.types.as_slice().to_vec()
950 ty::Predicate::Equate(ty::Binder(ref data)) => {
953 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
956 ty::Predicate::RegionOutlives(..) => {
959 ty::Predicate::Projection(ref data) => {
960 let trait_inputs = data.0.projection_ty.trait_ref.substs.types.as_slice();
963 .chain(Some(data.0.ty))
966 ty::Predicate::WellFormed(data) => {
969 ty::Predicate::ObjectSafe(_trait_def_id) => {
974 // The only reason to collect into a vector here is that I was
975 // too lazy to make the full (somewhat complicated) iterator
976 // type that would be needed here. But I wanted this fn to
977 // return an iterator conceptually, rather than a `Vec`, so as
978 // to be closer to `Ty::walk`.
982 pub fn has_escaping_regions(&self) -> bool {
984 Predicate::Trait(ref trait_ref) => trait_ref.has_escaping_regions(),
985 Predicate::Equate(ref p) => p.has_escaping_regions(),
986 Predicate::RegionOutlives(ref p) => p.has_escaping_regions(),
987 Predicate::TypeOutlives(ref p) => p.has_escaping_regions(),
988 Predicate::Projection(ref p) => p.has_escaping_regions(),
989 Predicate::WellFormed(p) => p.has_escaping_regions(),
990 Predicate::ObjectSafe(_trait_def_id) => false,
994 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
996 Predicate::Trait(ref t) => {
997 Some(t.to_poly_trait_ref())
999 Predicate::Projection(..) |
1000 Predicate::Equate(..) |
1001 Predicate::RegionOutlives(..) |
1002 Predicate::WellFormed(..) |
1003 Predicate::ObjectSafe(..) |
1004 Predicate::TypeOutlives(..) => {
1011 /// Represents the bounds declared on a particular set of type
1012 /// parameters. Should eventually be generalized into a flag list of
1013 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1014 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1015 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1016 /// the `GenericPredicates` are expressed in terms of the bound type
1017 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1018 /// represented a set of bounds for some particular instantiation,
1019 /// meaning that the generic parameters have been substituted with
1024 /// struct Foo<T,U:Bar<T>> { ... }
1026 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1027 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1028 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1029 /// [usize:Bar<isize>]]`.
1031 pub struct InstantiatedPredicates<'tcx> {
1032 pub predicates: VecPerParamSpace<Predicate<'tcx>>,
1035 impl<'tcx> InstantiatedPredicates<'tcx> {
1036 pub fn empty() -> InstantiatedPredicates<'tcx> {
1037 InstantiatedPredicates { predicates: VecPerParamSpace::empty() }
1040 pub fn has_escaping_regions(&self) -> bool {
1041 self.predicates.any(|p| p.has_escaping_regions())
1044 pub fn is_empty(&self) -> bool {
1045 self.predicates.is_empty()
1049 impl<'tcx> TraitRef<'tcx> {
1050 pub fn new(def_id: DefId, substs: &'tcx Substs<'tcx>) -> TraitRef<'tcx> {
1051 TraitRef { def_id: def_id, substs: substs }
1054 pub fn self_ty(&self) -> Ty<'tcx> {
1055 self.substs.self_ty().unwrap()
1058 pub fn input_types(&self) -> &[Ty<'tcx>] {
1059 // Select only the "input types" from a trait-reference. For
1060 // now this is all the types that appear in the
1061 // trait-reference, but it should eventually exclude
1062 // associated types.
1063 self.substs.types.as_slice()
1067 /// When type checking, we use the `ParameterEnvironment` to track
1068 /// details about the type/lifetime parameters that are in scope.
1069 /// It primarily stores the bounds information.
1071 /// Note: This information might seem to be redundant with the data in
1072 /// `tcx.ty_param_defs`, but it is not. That table contains the
1073 /// parameter definitions from an "outside" perspective, but this
1074 /// struct will contain the bounds for a parameter as seen from inside
1075 /// the function body. Currently the only real distinction is that
1076 /// bound lifetime parameters are replaced with free ones, but in the
1077 /// future I hope to refine the representation of types so as to make
1078 /// more distinctions clearer.
1080 pub struct ParameterEnvironment<'a, 'tcx:'a> {
1081 pub tcx: &'a ctxt<'tcx>,
1083 /// See `construct_free_substs` for details.
1084 pub free_substs: Substs<'tcx>,
1086 /// Each type parameter has an implicit region bound that
1087 /// indicates it must outlive at least the function body (the user
1088 /// may specify stronger requirements). This field indicates the
1089 /// region of the callee.
1090 pub implicit_region_bound: ty::Region,
1092 /// Obligations that the caller must satisfy. This is basically
1093 /// the set of bounds on the in-scope type parameters, translated
1094 /// into Obligations, and elaborated and normalized.
1095 pub caller_bounds: Vec<ty::Predicate<'tcx>>,
1097 /// Caches the results of trait selection. This cache is used
1098 /// for things that have to do with the parameters in scope.
1099 pub selection_cache: traits::SelectionCache<'tcx>,
1101 /// Scope that is attached to free regions for this scope. This
1102 /// is usually the id of the fn body, but for more abstract scopes
1103 /// like structs we often use the node-id of the struct.
1105 /// FIXME(#3696). It would be nice to refactor so that free
1106 /// regions don't have this implicit scope and instead introduce
1107 /// relationships in the environment.
1108 pub free_id: ast::NodeId,
1111 impl<'a, 'tcx> ParameterEnvironment<'a, 'tcx> {
1112 pub fn with_caller_bounds(&self,
1113 caller_bounds: Vec<ty::Predicate<'tcx>>)
1114 -> ParameterEnvironment<'a,'tcx>
1116 ParameterEnvironment {
1118 free_substs: self.free_substs.clone(),
1119 implicit_region_bound: self.implicit_region_bound,
1120 caller_bounds: caller_bounds,
1121 selection_cache: traits::SelectionCache::new(),
1122 free_id: self.free_id,
1126 pub fn for_item(cx: &'a ctxt<'tcx>, id: NodeId) -> ParameterEnvironment<'a, 'tcx> {
1127 match cx.map.find(id) {
1128 Some(ast_map::NodeImplItem(ref impl_item)) => {
1129 match impl_item.node {
1130 hir::TypeImplItem(_) => {
1131 // associated types don't have their own entry (for some reason),
1132 // so for now just grab environment for the impl
1133 let impl_id = cx.map.get_parent(id);
1134 let impl_def_id = DefId::local(impl_id);
1135 let scheme = cx.lookup_item_type(impl_def_id);
1136 let predicates = cx.lookup_predicates(impl_def_id);
1137 cx.construct_parameter_environment(impl_item.span,
1142 hir::ConstImplItem(_, _) => {
1143 let def_id = DefId::local(id);
1144 let scheme = cx.lookup_item_type(def_id);
1145 let predicates = cx.lookup_predicates(def_id);
1146 cx.construct_parameter_environment(impl_item.span,
1151 hir::MethodImplItem(_, ref body) => {
1152 let method_def_id = DefId::local(id);
1153 match cx.impl_or_trait_item(method_def_id) {
1154 MethodTraitItem(ref method_ty) => {
1155 let method_generics = &method_ty.generics;
1156 let method_bounds = &method_ty.predicates;
1157 cx.construct_parameter_environment(
1165 .bug("ParameterEnvironment::for_item(): \
1166 got non-method item from impl method?!")
1172 Some(ast_map::NodeTraitItem(trait_item)) => {
1173 match trait_item.node {
1174 hir::TypeTraitItem(..) => {
1175 // associated types don't have their own entry (for some reason),
1176 // so for now just grab environment for the trait
1177 let trait_id = cx.map.get_parent(id);
1178 let trait_def_id = DefId::local(trait_id);
1179 let trait_def = cx.lookup_trait_def(trait_def_id);
1180 let predicates = cx.lookup_predicates(trait_def_id);
1181 cx.construct_parameter_environment(trait_item.span,
1182 &trait_def.generics,
1186 hir::ConstTraitItem(..) => {
1187 let def_id = DefId::local(id);
1188 let scheme = cx.lookup_item_type(def_id);
1189 let predicates = cx.lookup_predicates(def_id);
1190 cx.construct_parameter_environment(trait_item.span,
1195 hir::MethodTraitItem(_, ref body) => {
1196 // for the body-id, use the id of the body
1197 // block, unless this is a trait method with
1198 // no default, then fallback to the method id.
1199 let body_id = body.as_ref().map(|b| b.id).unwrap_or(id);
1200 let method_def_id = DefId::local(id);
1202 match cx.impl_or_trait_item(method_def_id) {
1203 MethodTraitItem(ref method_ty) => {
1204 let method_generics = &method_ty.generics;
1205 let method_bounds = &method_ty.predicates;
1206 cx.construct_parameter_environment(
1214 .bug("ParameterEnvironment::for_item(): \
1215 got non-method item from provided \
1222 Some(ast_map::NodeItem(item)) => {
1224 hir::ItemFn(_, _, _, _, _, ref body) => {
1225 // We assume this is a function.
1226 let fn_def_id = DefId::local(id);
1227 let fn_scheme = cx.lookup_item_type(fn_def_id);
1228 let fn_predicates = cx.lookup_predicates(fn_def_id);
1230 cx.construct_parameter_environment(item.span,
1231 &fn_scheme.generics,
1236 hir::ItemStruct(..) |
1238 hir::ItemConst(..) |
1239 hir::ItemStatic(..) => {
1240 let def_id = DefId::local(id);
1241 let scheme = cx.lookup_item_type(def_id);
1242 let predicates = cx.lookup_predicates(def_id);
1243 cx.construct_parameter_environment(item.span,
1248 hir::ItemTrait(..) => {
1249 let def_id = DefId::local(id);
1250 let trait_def = cx.lookup_trait_def(def_id);
1251 let predicates = cx.lookup_predicates(def_id);
1252 cx.construct_parameter_environment(item.span,
1253 &trait_def.generics,
1258 cx.sess.span_bug(item.span,
1259 "ParameterEnvironment::from_item():
1260 can't create a parameter \
1261 environment for this kind of item")
1265 Some(ast_map::NodeExpr(..)) => {
1266 // This is a convenience to allow closures to work.
1267 ParameterEnvironment::for_item(cx, cx.map.get_parent(id))
1270 cx.sess.bug(&format!("ParameterEnvironment::from_item(): \
1271 `{}` is not an item",
1272 cx.map.node_to_string(id)))
1278 /// A "type scheme", in ML terminology, is a type combined with some
1279 /// set of generic types that the type is, well, generic over. In Rust
1280 /// terms, it is the "type" of a fn item or struct -- this type will
1281 /// include various generic parameters that must be substituted when
1282 /// the item/struct is referenced. That is called converting the type
1283 /// scheme to a monotype.
1285 /// - `generics`: the set of type parameters and their bounds
1286 /// - `ty`: the base types, which may reference the parameters defined
1289 /// Note that TypeSchemes are also sometimes called "polytypes" (and
1290 /// in fact this struct used to carry that name, so you may find some
1291 /// stray references in a comment or something). We try to reserve the
1292 /// "poly" prefix to refer to higher-ranked things, as in
1295 /// Note that each item also comes with predicates, see
1296 /// `lookup_predicates`.
1297 #[derive(Clone, Debug)]
1298 pub struct TypeScheme<'tcx> {
1299 pub generics: Generics<'tcx>,
1304 flags TraitFlags: u32 {
1305 const NO_TRAIT_FLAGS = 0,
1306 const HAS_DEFAULT_IMPL = 1 << 0,
1307 const IS_OBJECT_SAFE = 1 << 1,
1308 const OBJECT_SAFETY_VALID = 1 << 2,
1309 const IMPLS_VALID = 1 << 3,
1313 /// As `TypeScheme` but for a trait ref.
1314 pub struct TraitDef<'tcx> {
1315 pub unsafety: hir::Unsafety,
1317 /// If `true`, then this trait had the `#[rustc_paren_sugar]`
1318 /// attribute, indicating that it should be used with `Foo()`
1319 /// sugar. This is a temporary thing -- eventually any trait wil
1320 /// be usable with the sugar (or without it).
1321 pub paren_sugar: bool,
1323 /// Generic type definitions. Note that `Self` is listed in here
1324 /// as having a single bound, the trait itself (e.g., in the trait
1325 /// `Eq`, there is a single bound `Self : Eq`). This is so that
1326 /// default methods get to assume that the `Self` parameters
1327 /// implements the trait.
1328 pub generics: Generics<'tcx>,
1330 pub trait_ref: TraitRef<'tcx>,
1332 /// A list of the associated types defined in this trait. Useful
1333 /// for resolving `X::Foo` type markers.
1334 pub associated_type_names: Vec<Name>,
1336 // Impls of this trait. To allow for quicker lookup, the impls are indexed
1337 // by a simplified version of their Self type: impls with a simplifiable
1338 // Self are stored in nonblanket_impls keyed by it, while all other impls
1339 // are stored in blanket_impls.
1341 /// Impls of the trait.
1342 pub nonblanket_impls: RefCell<
1343 FnvHashMap<fast_reject::SimplifiedType, Vec<DefId>>
1346 /// Blanket impls associated with the trait.
1347 pub blanket_impls: RefCell<Vec<DefId>>,
1350 pub flags: Cell<TraitFlags>
1353 impl<'tcx> TraitDef<'tcx> {
1354 // returns None if not yet calculated
1355 pub fn object_safety(&self) -> Option<bool> {
1356 if self.flags.get().intersects(TraitFlags::OBJECT_SAFETY_VALID) {
1357 Some(self.flags.get().intersects(TraitFlags::IS_OBJECT_SAFE))
1363 pub fn set_object_safety(&self, is_safe: bool) {
1364 assert!(self.object_safety().map(|cs| cs == is_safe).unwrap_or(true));
1366 self.flags.get() | if is_safe {
1367 TraitFlags::OBJECT_SAFETY_VALID | TraitFlags::IS_OBJECT_SAFE
1369 TraitFlags::OBJECT_SAFETY_VALID
1374 /// Records a trait-to-implementation mapping.
1375 pub fn record_impl(&self,
1378 impl_trait_ref: TraitRef<'tcx>) {
1379 debug!("TraitDef::record_impl for {:?}, from {:?}",
1380 self, impl_trait_ref);
1382 // We don't want to borrow_mut after we already populated all impls,
1383 // so check if an impl is present with an immutable borrow first.
1384 if let Some(sty) = fast_reject::simplify_type(tcx,
1385 impl_trait_ref.self_ty(), false) {
1386 if let Some(is) = self.nonblanket_impls.borrow().get(&sty) {
1387 if is.contains(&impl_def_id) {
1388 return // duplicate - skip
1392 self.nonblanket_impls.borrow_mut().entry(sty).or_insert(vec![]).push(impl_def_id)
1394 if self.blanket_impls.borrow().contains(&impl_def_id) {
1395 return // duplicate - skip
1397 self.blanket_impls.borrow_mut().push(impl_def_id)
1402 pub fn for_each_impl<F: FnMut(DefId)>(&self, tcx: &ctxt<'tcx>, mut f: F) {
1403 tcx.populate_implementations_for_trait_if_necessary(self.trait_ref.def_id);
1405 for &impl_def_id in self.blanket_impls.borrow().iter() {
1409 for v in self.nonblanket_impls.borrow().values() {
1410 for &impl_def_id in v {
1416 /// Iterate over every impl that could possibly match the
1417 /// self-type `self_ty`.
1418 pub fn for_each_relevant_impl<F: FnMut(DefId)>(&self,
1423 tcx.populate_implementations_for_trait_if_necessary(self.trait_ref.def_id);
1425 for &impl_def_id in self.blanket_impls.borrow().iter() {
1429 // simplify_type(.., false) basically replaces type parameters and
1430 // projections with infer-variables. This is, of course, done on
1431 // the impl trait-ref when it is instantiated, but not on the
1432 // predicate trait-ref which is passed here.
1434 // for example, if we match `S: Copy` against an impl like
1435 // `impl<T:Copy> Copy for Option<T>`, we replace the type variable
1436 // in `Option<T>` with an infer variable, to `Option<_>` (this
1437 // doesn't actually change fast_reject output), but we don't
1438 // replace `S` with anything - this impl of course can't be
1439 // selected, and as there are hundreds of similar impls,
1440 // considering them would significantly harm performance.
1441 if let Some(simp) = fast_reject::simplify_type(tcx, self_ty, true) {
1442 if let Some(impls) = self.nonblanket_impls.borrow().get(&simp) {
1443 for &impl_def_id in impls {
1448 for v in self.nonblanket_impls.borrow().values() {
1449 for &impl_def_id in v {
1459 flags AdtFlags: u32 {
1460 const NO_ADT_FLAGS = 0,
1461 const IS_ENUM = 1 << 0,
1462 const IS_DTORCK = 1 << 1, // is this a dtorck type?
1463 const IS_DTORCK_VALID = 1 << 2,
1464 const IS_PHANTOM_DATA = 1 << 3,
1465 const IS_SIMD = 1 << 4,
1466 const IS_FUNDAMENTAL = 1 << 5,
1467 const IS_NO_DROP_FLAG = 1 << 6,
1471 pub type AdtDef<'tcx> = &'tcx AdtDefData<'tcx, 'static>;
1472 pub type VariantDef<'tcx> = &'tcx VariantDefData<'tcx, 'static>;
1473 pub type FieldDef<'tcx> = &'tcx FieldDefData<'tcx, 'static>;
1475 // See comment on AdtDefData for explanation
1476 pub type AdtDefMaster<'tcx> = &'tcx AdtDefData<'tcx, 'tcx>;
1477 pub type VariantDefMaster<'tcx> = &'tcx VariantDefData<'tcx, 'tcx>;
1478 pub type FieldDefMaster<'tcx> = &'tcx FieldDefData<'tcx, 'tcx>;
1480 pub struct VariantDefData<'tcx, 'container: 'tcx> {
1482 pub name: Name, // struct's name if this is a struct
1484 pub fields: Vec<FieldDefData<'tcx, 'container>>
1487 pub struct FieldDefData<'tcx, 'container: 'tcx> {
1488 /// The field's DefId. NOTE: the fields of tuple-like enum variants
1489 /// are not real items, and don't have entries in tcache etc.
1491 /// special_idents::unnamed_field.name
1492 /// if this is a tuple-like field
1494 pub vis: hir::Visibility,
1495 /// TyIVar is used here to allow for variance (see the doc at
1497 ty: ivar::TyIVar<'tcx, 'container>
1500 /// The definition of an abstract data type - a struct or enum.
1502 /// These are all interned (by intern_adt_def) into the adt_defs
1505 /// Because of the possibility of nested tcx-s, this type
1506 /// needs 2 lifetimes: the traditional variant lifetime ('tcx)
1507 /// bounding the lifetime of the inner types is of course necessary.
1508 /// However, it is not sufficient - types from a child tcx must
1509 /// not be leaked into the master tcx by being stored in an AdtDefData.
1511 /// The 'container lifetime ensures that by outliving the container
1512 /// tcx and preventing shorter-lived types from being inserted. When
1513 /// write access is not needed, the 'container lifetime can be
1514 /// erased to 'static, which can be done by the AdtDef wrapper.
1515 pub struct AdtDefData<'tcx, 'container: 'tcx> {
1517 pub variants: Vec<VariantDefData<'tcx, 'container>>,
1518 destructor: Cell<Option<DefId>>,
1519 flags: Cell<AdtFlags>,
1522 impl<'tcx, 'container> PartialEq for AdtDefData<'tcx, 'container> {
1523 // AdtDefData are always interned and this is part of TyS equality
1525 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1528 impl<'tcx, 'container> Eq for AdtDefData<'tcx, 'container> {}
1530 impl<'tcx, 'container> Hash for AdtDefData<'tcx, 'container> {
1532 fn hash<H: Hasher>(&self, s: &mut H) {
1533 (self as *const AdtDefData).hash(s)
1538 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1539 pub enum AdtKind { Struct, Enum }
1541 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1542 pub enum VariantKind { Dict, Tuple, Unit }
1544 impl<'tcx, 'container> AdtDefData<'tcx, 'container> {
1545 fn new(tcx: &ctxt<'tcx>,
1548 variants: Vec<VariantDefData<'tcx, 'container>>) -> Self {
1549 let mut flags = AdtFlags::NO_ADT_FLAGS;
1550 let attrs = tcx.get_attrs(did);
1551 if attr::contains_name(&attrs, "fundamental") {
1552 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1554 if attr::contains_name(&attrs, "unsafe_no_drop_flag") {
1555 flags = flags | AdtFlags::IS_NO_DROP_FLAG;
1557 if tcx.lookup_simd(did) {
1558 flags = flags | AdtFlags::IS_SIMD;
1560 if Some(did) == tcx.lang_items.phantom_data() {
1561 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1563 if let AdtKind::Enum = kind {
1564 flags = flags | AdtFlags::IS_ENUM;
1569 flags: Cell::new(flags),
1570 destructor: Cell::new(None)
1574 fn calculate_dtorck(&'tcx self, tcx: &ctxt<'tcx>) {
1575 if tcx.is_adt_dtorck(self) {
1576 self.flags.set(self.flags.get() | AdtFlags::IS_DTORCK);
1578 self.flags.set(self.flags.get() | AdtFlags::IS_DTORCK_VALID)
1581 /// Returns the kind of the ADT - Struct or Enum.
1583 pub fn adt_kind(&self) -> AdtKind {
1584 if self.flags.get().intersects(AdtFlags::IS_ENUM) {
1591 /// Returns whether this is a dtorck type. If this returns
1592 /// true, this type being safe for destruction requires it to be
1593 /// alive; Otherwise, only the contents are required to be.
1595 pub fn is_dtorck(&'tcx self, tcx: &ctxt<'tcx>) -> bool {
1596 if !self.flags.get().intersects(AdtFlags::IS_DTORCK_VALID) {
1597 self.calculate_dtorck(tcx)
1599 self.flags.get().intersects(AdtFlags::IS_DTORCK)
1602 /// Returns whether this type is #[fundamental] for the purposes
1603 /// of coherence checking.
1605 pub fn is_fundamental(&self) -> bool {
1606 self.flags.get().intersects(AdtFlags::IS_FUNDAMENTAL)
1610 pub fn is_simd(&self) -> bool {
1611 self.flags.get().intersects(AdtFlags::IS_SIMD)
1614 /// Returns true if this is PhantomData<T>.
1616 pub fn is_phantom_data(&self) -> bool {
1617 self.flags.get().intersects(AdtFlags::IS_PHANTOM_DATA)
1620 /// Returns whether this type has a destructor.
1621 pub fn has_dtor(&self) -> bool {
1622 match self.dtor_kind() {
1624 TraitDtor(..) => true
1628 /// Asserts this is a struct and returns the struct's unique
1630 pub fn struct_variant(&self) -> &VariantDefData<'tcx, 'container> {
1631 assert!(self.adt_kind() == AdtKind::Struct);
1636 pub fn type_scheme(&self, tcx: &ctxt<'tcx>) -> TypeScheme<'tcx> {
1637 tcx.lookup_item_type(self.did)
1641 pub fn predicates(&self, tcx: &ctxt<'tcx>) -> GenericPredicates<'tcx> {
1642 tcx.lookup_predicates(self.did)
1645 /// Returns an iterator over all fields contained
1648 pub fn all_fields(&self) ->
1650 slice::Iter<VariantDefData<'tcx, 'container>>,
1651 slice::Iter<FieldDefData<'tcx, 'container>>,
1652 for<'s> fn(&'s VariantDefData<'tcx, 'container>)
1653 -> slice::Iter<'s, FieldDefData<'tcx, 'container>>
1655 self.variants.iter().flat_map(VariantDefData::fields_iter)
1659 pub fn is_empty(&self) -> bool {
1660 self.variants.is_empty()
1664 pub fn is_univariant(&self) -> bool {
1665 self.variants.len() == 1
1668 pub fn is_payloadfree(&self) -> bool {
1669 !self.variants.is_empty() &&
1670 self.variants.iter().all(|v| v.fields.is_empty())
1673 pub fn variant_with_id(&self, vid: DefId) -> &VariantDefData<'tcx, 'container> {
1676 .find(|v| v.did == vid)
1677 .expect("variant_with_id: unknown variant")
1680 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1683 .position(|v| v.did == vid)
1684 .expect("variant_index_with_id: unknown variant")
1687 pub fn variant_of_def(&self, def: def::Def) -> &VariantDefData<'tcx, 'container> {
1689 def::DefVariant(_, vid, _) => self.variant_with_id(vid),
1690 def::DefStruct(..) | def::DefTy(..) => self.struct_variant(),
1691 _ => panic!("unexpected def {:?} in variant_of_def", def)
1695 pub fn destructor(&self) -> Option<DefId> {
1696 self.destructor.get()
1699 pub fn set_destructor(&self, dtor: DefId) {
1700 assert!(self.destructor.get().is_none());
1701 self.destructor.set(Some(dtor));
1704 pub fn dtor_kind(&self) -> DtorKind {
1705 match self.destructor.get() {
1707 TraitDtor(!self.flags.get().intersects(AdtFlags::IS_NO_DROP_FLAG))
1714 impl<'tcx, 'container> VariantDefData<'tcx, 'container> {
1716 fn fields_iter(&self) -> slice::Iter<FieldDefData<'tcx, 'container>> {
1720 pub fn kind(&self) -> VariantKind {
1721 match self.fields.get(0) {
1722 None => VariantKind::Unit,
1723 Some(&FieldDefData { name, .. }) if name == special_idents::unnamed_field.name => {
1726 Some(_) => VariantKind::Dict
1730 pub fn is_tuple_struct(&self) -> bool {
1731 self.kind() == VariantKind::Tuple
1735 pub fn find_field_named(&self,
1737 -> Option<&FieldDefData<'tcx, 'container>> {
1738 self.fields.iter().find(|f| f.name == name)
1742 pub fn field_named(&self, name: ast::Name) -> &FieldDefData<'tcx, 'container> {
1743 self.find_field_named(name).unwrap()
1747 impl<'tcx, 'container> FieldDefData<'tcx, 'container> {
1748 pub fn new(did: DefId,
1750 vis: hir::Visibility) -> Self {
1755 ty: ivar::TyIVar::new()
1759 pub fn ty(&self, tcx: &ctxt<'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1760 self.unsubst_ty().subst(tcx, subst)
1763 pub fn unsubst_ty(&self) -> Ty<'tcx> {
1767 pub fn fulfill_ty(&self, ty: Ty<'container>) {
1768 self.ty.fulfill(ty);
1772 /// Records the substitutions used to translate the polytype for an
1773 /// item into the monotype of an item reference.
1775 pub struct ItemSubsts<'tcx> {
1776 pub substs: Substs<'tcx>,
1779 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Debug, RustcEncodable, RustcDecodable)]
1780 pub enum ClosureKind {
1781 // Warning: Ordering is significant here! The ordering is chosen
1782 // because the trait Fn is a subtrait of FnMut and so in turn, and
1783 // hence we order it so that Fn < FnMut < FnOnce.
1790 pub fn trait_did(&self, cx: &ctxt) -> DefId {
1791 let result = match *self {
1792 FnClosureKind => cx.lang_items.require(FnTraitLangItem),
1793 FnMutClosureKind => {
1794 cx.lang_items.require(FnMutTraitLangItem)
1796 FnOnceClosureKind => {
1797 cx.lang_items.require(FnOnceTraitLangItem)
1801 Ok(trait_did) => trait_did,
1802 Err(err) => cx.sess.fatal(&err[..]),
1806 /// True if this a type that impls this closure kind
1807 /// must also implement `other`.
1808 pub fn extends(self, other: ty::ClosureKind) -> bool {
1809 match (self, other) {
1810 (FnClosureKind, FnClosureKind) => true,
1811 (FnClosureKind, FnMutClosureKind) => true,
1812 (FnClosureKind, FnOnceClosureKind) => true,
1813 (FnMutClosureKind, FnMutClosureKind) => true,
1814 (FnMutClosureKind, FnOnceClosureKind) => true,
1815 (FnOnceClosureKind, FnOnceClosureKind) => true,
1821 impl<'tcx> TyS<'tcx> {
1822 /// Iterator that walks `self` and any types reachable from
1823 /// `self`, in depth-first order. Note that just walks the types
1824 /// that appear in `self`, it does not descend into the fields of
1825 /// structs or variants. For example:
1828 /// isize => { isize }
1829 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
1830 /// [isize] => { [isize], isize }
1832 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
1833 TypeWalker::new(self)
1836 /// Iterator that walks the immediate children of `self`. Hence
1837 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
1838 /// (but not `i32`, like `walk`).
1839 pub fn walk_shallow(&'tcx self) -> IntoIter<Ty<'tcx>> {
1840 walk::walk_shallow(self)
1843 /// Walks `ty` and any types appearing within `ty`, invoking the
1844 /// callback `f` on each type. If the callback returns false, then the
1845 /// children of the current type are ignored.
1847 /// Note: prefer `ty.walk()` where possible.
1848 pub fn maybe_walk<F>(&'tcx self, mut f: F)
1849 where F : FnMut(Ty<'tcx>) -> bool
1851 let mut walker = self.walk();
1852 while let Some(ty) = walker.next() {
1854 walker.skip_current_subtree();
1860 impl<'tcx> ItemSubsts<'tcx> {
1861 pub fn empty() -> ItemSubsts<'tcx> {
1862 ItemSubsts { substs: Substs::empty() }
1865 pub fn is_noop(&self) -> bool {
1866 self.substs.is_noop()
1870 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1871 pub enum LvaluePreference {
1876 impl LvaluePreference {
1877 pub fn from_mutbl(m: hir::Mutability) -> Self {
1879 hir::MutMutable => PreferMutLvalue,
1880 hir::MutImmutable => NoPreference,
1885 /// Helper for looking things up in the various maps that are populated during
1886 /// typeck::collect (e.g., `cx.impl_or_trait_items`, `cx.tcache`, etc). All of
1887 /// these share the pattern that if the id is local, it should have been loaded
1888 /// into the map by the `typeck::collect` phase. If the def-id is external,
1889 /// then we have to go consult the crate loading code (and cache the result for
1891 fn lookup_locally_or_in_crate_store<V, F>(descr: &str,
1893 map: &RefCell<DefIdMap<V>>,
1894 load_external: F) -> V where
1898 match map.borrow().get(&def_id).cloned() {
1899 Some(v) => { return v; }
1903 if def_id.is_local() {
1904 panic!("No def'n found for {:?} in tcx.{}", def_id, descr);
1906 let v = load_external();
1907 map.borrow_mut().insert(def_id, v.clone());
1912 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
1914 hir::MutMutable => MutBorrow,
1915 hir::MutImmutable => ImmBorrow,
1919 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
1920 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
1921 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
1923 pub fn to_mutbl_lossy(self) -> hir::Mutability {
1925 MutBorrow => hir::MutMutable,
1926 ImmBorrow => hir::MutImmutable,
1928 // We have no type corresponding to a unique imm borrow, so
1929 // use `&mut`. It gives all the capabilities of an `&uniq`
1930 // and hence is a safe "over approximation".
1931 UniqueImmBorrow => hir::MutMutable,
1935 pub fn to_user_str(&self) -> &'static str {
1937 MutBorrow => "mutable",
1938 ImmBorrow => "immutable",
1939 UniqueImmBorrow => "uniquely immutable",
1944 impl<'tcx> ctxt<'tcx> {
1945 pub fn node_id_to_type(&self, id: NodeId) -> Ty<'tcx> {
1946 match self.node_id_to_type_opt(id) {
1948 None => self.sess.bug(
1949 &format!("node_id_to_type: no type for node `{}`",
1950 self.map.node_to_string(id)))
1954 pub fn node_id_to_type_opt(&self, id: NodeId) -> Option<Ty<'tcx>> {
1955 self.tables.borrow().node_types.get(&id).cloned()
1958 pub fn node_id_item_substs(&self, id: NodeId) -> ItemSubsts<'tcx> {
1959 match self.tables.borrow().item_substs.get(&id) {
1960 None => ItemSubsts::empty(),
1961 Some(ts) => ts.clone(),
1965 // Returns the type of a pattern as a monotype. Like @expr_ty, this function
1966 // doesn't provide type parameter substitutions.
1967 pub fn pat_ty(&self, pat: &hir::Pat) -> Ty<'tcx> {
1968 self.node_id_to_type(pat.id)
1970 pub fn pat_ty_opt(&self, pat: &hir::Pat) -> Option<Ty<'tcx>> {
1971 self.node_id_to_type_opt(pat.id)
1974 // Returns the type of an expression as a monotype.
1976 // NB (1): This is the PRE-ADJUSTMENT TYPE for the expression. That is, in
1977 // some cases, we insert `AutoAdjustment` annotations such as auto-deref or
1978 // auto-ref. The type returned by this function does not consider such
1979 // adjustments. See `expr_ty_adjusted()` instead.
1981 // NB (2): This type doesn't provide type parameter substitutions; e.g. if you
1982 // ask for the type of "id" in "id(3)", it will return "fn(&isize) -> isize"
1983 // instead of "fn(ty) -> T with T = isize".
1984 pub fn expr_ty(&self, expr: &hir::Expr) -> Ty<'tcx> {
1985 self.node_id_to_type(expr.id)
1988 pub fn expr_ty_opt(&self, expr: &hir::Expr) -> Option<Ty<'tcx>> {
1989 self.node_id_to_type_opt(expr.id)
1992 /// Returns the type of `expr`, considering any `AutoAdjustment`
1993 /// entry recorded for that expression.
1995 /// It would almost certainly be better to store the adjusted ty in with
1996 /// the `AutoAdjustment`, but I opted not to do this because it would
1997 /// require serializing and deserializing the type and, although that's not
1998 /// hard to do, I just hate that code so much I didn't want to touch it
1999 /// unless it was to fix it properly, which seemed a distraction from the
2000 /// thread at hand! -nmatsakis
2001 pub fn expr_ty_adjusted(&self, expr: &hir::Expr) -> Ty<'tcx> {
2003 .adjust(self, expr.span, expr.id,
2004 self.tables.borrow().adjustments.get(&expr.id),
2006 self.tables.borrow().method_map.get(&method_call).map(|method| method.ty)
2010 pub fn expr_span(&self, id: NodeId) -> Span {
2011 match self.map.find(id) {
2012 Some(ast_map::NodeExpr(e)) => {
2016 self.sess.bug(&format!("Node id {} is not an expr: {:?}",
2020 self.sess.bug(&format!("Node id {} is not present \
2021 in the node map", id));
2026 pub fn local_var_name_str(&self, id: NodeId) -> InternedString {
2027 match self.map.find(id) {
2028 Some(ast_map::NodeLocal(pat)) => {
2030 hir::PatIdent(_, ref path1, _) => path1.node.name.as_str(),
2032 self.sess.bug(&format!("Variable id {} maps to {:?}, not local", id, pat));
2036 r => self.sess.bug(&format!("Variable id {} maps to {:?}, not local", id, r)),
2040 pub fn resolve_expr(&self, expr: &hir::Expr) -> def::Def {
2041 match self.def_map.borrow().get(&expr.id) {
2042 Some(def) => def.full_def(),
2044 self.sess.span_bug(expr.span, &format!(
2045 "no def-map entry for expr {}", expr.id));
2050 pub fn expr_is_lval(&self, expr: &hir::Expr) -> bool {
2052 hir::ExprPath(..) => {
2053 // We can't use resolve_expr here, as this needs to run on broken
2054 // programs. We don't need to through - associated items are all
2056 match self.def_map.borrow().get(&expr.id) {
2057 Some(&def::PathResolution {
2058 base_def: def::DefStatic(..), ..
2059 }) | Some(&def::PathResolution {
2060 base_def: def::DefUpvar(..), ..
2061 }) | Some(&def::PathResolution {
2062 base_def: def::DefLocal(..), ..
2069 None => self.sess.span_bug(expr.span, &format!(
2070 "no def for path {}", expr.id))
2074 hir::ExprUnary(hir::UnDeref, _) |
2075 hir::ExprField(..) |
2076 hir::ExprTupField(..) |
2077 hir::ExprIndex(..) => {
2082 hir::ExprMethodCall(..) |
2083 hir::ExprStruct(..) |
2084 hir::ExprRange(..) |
2087 hir::ExprMatch(..) |
2088 hir::ExprClosure(..) |
2089 hir::ExprBlock(..) |
2090 hir::ExprRepeat(..) |
2092 hir::ExprBreak(..) |
2093 hir::ExprAgain(..) |
2095 hir::ExprWhile(..) |
2097 hir::ExprAssign(..) |
2098 hir::ExprInlineAsm(..) |
2099 hir::ExprAssignOp(..) |
2101 hir::ExprUnary(..) |
2103 hir::ExprAddrOf(..) |
2104 hir::ExprBinary(..) |
2105 hir::ExprCast(..) => {
2109 hir::ExprParen(ref e) => self.expr_is_lval(e),
2113 pub fn provided_source(&self, id: DefId) -> Option<DefId> {
2114 self.provided_method_sources.borrow().get(&id).cloned()
2117 pub fn provided_trait_methods(&self, id: DefId) -> Vec<Rc<Method<'tcx>>> {
2119 if let ItemTrait(_, _, _, ref ms) = self.map.expect_item(id.node).node {
2120 ms.iter().filter_map(|ti| {
2121 if let hir::MethodTraitItem(_, Some(_)) = ti.node {
2122 match self.impl_or_trait_item(DefId::local(ti.id)) {
2123 MethodTraitItem(m) => Some(m),
2125 self.sess.bug("provided_trait_methods(): \
2126 non-method item found from \
2127 looking up provided method?!")
2135 self.sess.bug(&format!("provided_trait_methods: `{:?}` is not a trait", id))
2138 csearch::get_provided_trait_methods(self, id)
2142 pub fn associated_consts(&self, id: DefId) -> Vec<Rc<AssociatedConst<'tcx>>> {
2144 match self.map.expect_item(id.node).node {
2145 ItemTrait(_, _, _, ref tis) => {
2146 tis.iter().filter_map(|ti| {
2147 if let hir::ConstTraitItem(_, _) = ti.node {
2148 match self.impl_or_trait_item(DefId::local(ti.id)) {
2149 ConstTraitItem(ac) => Some(ac),
2151 self.sess.bug("associated_consts(): \
2152 non-const item found from \
2153 looking up a constant?!")
2161 ItemImpl(_, _, _, _, _, ref iis) => {
2162 iis.iter().filter_map(|ii| {
2163 if let hir::ConstImplItem(_, _) = ii.node {
2164 match self.impl_or_trait_item(DefId::local(ii.id)) {
2165 ConstTraitItem(ac) => Some(ac),
2167 self.sess.bug("associated_consts(): \
2168 non-const item found from \
2169 looking up a constant?!")
2178 self.sess.bug(&format!("associated_consts: `{:?}` is not a trait \
2183 csearch::get_associated_consts(self, id)
2187 pub fn trait_items(&self, trait_did: DefId) -> Rc<Vec<ImplOrTraitItem<'tcx>>> {
2188 let mut trait_items = self.trait_items_cache.borrow_mut();
2189 match trait_items.get(&trait_did).cloned() {
2190 Some(trait_items) => trait_items,
2192 let def_ids = self.trait_item_def_ids(trait_did);
2193 let items: Rc<Vec<ImplOrTraitItem>> =
2194 Rc::new(def_ids.iter()
2195 .map(|d| self.impl_or_trait_item(d.def_id()))
2197 trait_items.insert(trait_did, items.clone());
2203 pub fn trait_impl_polarity(&self, id: DefId) -> Option<hir::ImplPolarity> {
2205 match self.map.find(id.node) {
2206 Some(ast_map::NodeItem(item)) => {
2208 hir::ItemImpl(_, polarity, _, _, _, _) => Some(polarity),
2215 csearch::get_impl_polarity(self, id)
2219 pub fn custom_coerce_unsized_kind(&self, did: DefId) -> adjustment::CustomCoerceUnsized {
2220 memoized(&self.custom_coerce_unsized_kinds, did, |did: DefId| {
2221 let (kind, src) = if did.krate != LOCAL_CRATE {
2222 (csearch::get_custom_coerce_unsized_kind(self, did), "external")
2230 self.sess.bug(&format!("custom_coerce_unsized_kind: \
2231 {} impl `{}` is missing its kind",
2232 src, self.item_path_str(did)));
2238 pub fn impl_or_trait_item(&self, id: DefId) -> ImplOrTraitItem<'tcx> {
2239 lookup_locally_or_in_crate_store(
2240 "impl_or_trait_items", id, &self.impl_or_trait_items,
2241 || csearch::get_impl_or_trait_item(self, id))
2244 pub fn trait_item_def_ids(&self, id: DefId) -> Rc<Vec<ImplOrTraitItemId>> {
2245 lookup_locally_or_in_crate_store(
2246 "trait_item_def_ids", id, &self.trait_item_def_ids,
2247 || Rc::new(csearch::get_trait_item_def_ids(&self.sess.cstore, id)))
2250 /// Returns the trait-ref corresponding to a given impl, or None if it is
2251 /// an inherent impl.
2252 pub fn impl_trait_ref(&self, id: DefId) -> Option<TraitRef<'tcx>> {
2253 lookup_locally_or_in_crate_store(
2254 "impl_trait_refs", id, &self.impl_trait_refs,
2255 || csearch::get_impl_trait(self, id))
2258 /// Returns whether this DefId refers to an impl
2259 pub fn is_impl(&self, id: DefId) -> bool {
2261 if let Some(ast_map::NodeItem(
2262 &hir::Item { node: hir::ItemImpl(..), .. })) = self.map.find(id.node) {
2268 csearch::is_impl(&self.sess.cstore, id)
2272 pub fn trait_ref_to_def_id(&self, tr: &hir::TraitRef) -> DefId {
2273 self.def_map.borrow().get(&tr.ref_id).expect("no def-map entry for trait").def_id()
2276 pub fn item_path_str(&self, id: DefId) -> String {
2277 self.with_path(id, |path| ast_map::path_to_string(path))
2280 pub fn with_path<T, F>(&self, id: DefId, f: F) -> T where
2281 F: FnOnce(ast_map::PathElems) -> T,
2284 self.map.with_path(id.node, f)
2286 f(csearch::get_item_path(self, id).iter().cloned().chain(LinkedPath::empty()))
2290 pub fn item_name(&self, id: DefId) -> ast::Name {
2292 self.map.get_path_elem(id.node).name()
2294 csearch::get_item_name(self, id)
2298 // Register a given item type
2299 pub fn register_item_type(&self, did: DefId, ty: TypeScheme<'tcx>) {
2300 self.tcache.borrow_mut().insert(did, ty);
2303 // If the given item is in an external crate, looks up its type and adds it to
2304 // the type cache. Returns the type parameters and type.
2305 pub fn lookup_item_type(&self, did: DefId) -> TypeScheme<'tcx> {
2306 lookup_locally_or_in_crate_store(
2307 "tcache", did, &self.tcache,
2308 || csearch::get_type(self, did))
2311 /// Given the did of a trait, returns its canonical trait ref.
2312 pub fn lookup_trait_def(&self, did: DefId) -> &'tcx TraitDef<'tcx> {
2313 lookup_locally_or_in_crate_store(
2314 "trait_defs", did, &self.trait_defs,
2315 || self.alloc_trait_def(csearch::get_trait_def(self, did))
2319 /// Given the did of an ADT, return a master reference to its
2320 /// definition. Unless you are planning on fulfilling the ADT's fields,
2321 /// use lookup_adt_def instead.
2322 pub fn lookup_adt_def_master(&self, did: DefId) -> AdtDefMaster<'tcx> {
2323 lookup_locally_or_in_crate_store(
2324 "adt_defs", did, &self.adt_defs,
2325 || csearch::get_adt_def(self, did)
2329 /// Given the did of an ADT, return a reference to its definition.
2330 pub fn lookup_adt_def(&self, did: DefId) -> AdtDef<'tcx> {
2331 // when reverse-variance goes away, a transmute::<AdtDefMaster,AdtDef>
2332 // woud be needed here.
2333 self.lookup_adt_def_master(did)
2336 /// Return the list of all interned ADT definitions
2337 pub fn adt_defs(&self) -> Vec<AdtDef<'tcx>> {
2338 self.adt_defs.borrow().values().cloned().collect()
2341 /// Given the did of an item, returns its full set of predicates.
2342 pub fn lookup_predicates(&self, did: DefId) -> GenericPredicates<'tcx> {
2343 lookup_locally_or_in_crate_store(
2344 "predicates", did, &self.predicates,
2345 || csearch::get_predicates(self, did))
2348 /// Given the did of a trait, returns its superpredicates.
2349 pub fn lookup_super_predicates(&self, did: DefId) -> GenericPredicates<'tcx> {
2350 lookup_locally_or_in_crate_store(
2351 "super_predicates", did, &self.super_predicates,
2352 || csearch::get_super_predicates(self, did))
2355 /// Get the attributes of a definition.
2356 pub fn get_attrs(&self, did: DefId) -> Cow<'tcx, [hir::Attribute]> {
2358 Cow::Borrowed(self.map.attrs(did.node))
2360 Cow::Owned(csearch::get_item_attrs(&self.sess.cstore, did))
2364 /// Determine whether an item is annotated with an attribute
2365 pub fn has_attr(&self, did: DefId, attr: &str) -> bool {
2366 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2369 /// Determine whether an item is annotated with `#[repr(packed)]`
2370 pub fn lookup_packed(&self, did: DefId) -> bool {
2371 self.lookup_repr_hints(did).contains(&attr::ReprPacked)
2374 /// Determine whether an item is annotated with `#[simd]`
2375 pub fn lookup_simd(&self, did: DefId) -> bool {
2376 self.has_attr(did, "simd")
2377 || self.lookup_repr_hints(did).contains(&attr::ReprSimd)
2380 /// Obtain the representation annotation for a struct definition.
2381 pub fn lookup_repr_hints(&self, did: DefId) -> Rc<Vec<attr::ReprAttr>> {
2382 memoized(&self.repr_hint_cache, did, |did: DefId| {
2383 Rc::new(if did.is_local() {
2384 self.get_attrs(did).iter().flat_map(|meta| {
2385 attr::find_repr_attrs(self.sess.diagnostic(), meta).into_iter()
2388 csearch::get_repr_attrs(&self.sess.cstore, did)
2393 pub fn item_variances(&self, item_id: DefId) -> Rc<ItemVariances> {
2394 lookup_locally_or_in_crate_store(
2395 "item_variance_map", item_id, &self.item_variance_map,
2396 || Rc::new(csearch::get_item_variances(&self.sess.cstore, item_id)))
2399 pub fn trait_has_default_impl(&self, trait_def_id: DefId) -> bool {
2400 self.populate_implementations_for_trait_if_necessary(trait_def_id);
2402 let def = self.lookup_trait_def(trait_def_id);
2403 def.flags.get().intersects(TraitFlags::HAS_DEFAULT_IMPL)
2406 /// Records a trait-to-implementation mapping.
2407 pub fn record_trait_has_default_impl(&self, trait_def_id: DefId) {
2408 let def = self.lookup_trait_def(trait_def_id);
2409 def.flags.set(def.flags.get() | TraitFlags::HAS_DEFAULT_IMPL)
2412 /// Load primitive inherent implementations if necessary
2413 pub fn populate_implementations_for_primitive_if_necessary(&self,
2414 primitive_def_id: DefId) {
2415 if primitive_def_id.is_local() {
2419 if self.populated_external_primitive_impls.borrow().contains(&primitive_def_id) {
2423 debug!("populate_implementations_for_primitive_if_necessary: searching for {:?}",
2426 let impl_items = csearch::get_impl_items(&self.sess.cstore, primitive_def_id);
2428 // Store the implementation info.
2429 self.impl_items.borrow_mut().insert(primitive_def_id, impl_items);
2430 self.populated_external_primitive_impls.borrow_mut().insert(primitive_def_id);
2433 /// Populates the type context with all the inherent implementations for
2434 /// the given type if necessary.
2435 pub fn populate_inherent_implementations_for_type_if_necessary(&self,
2437 if type_id.is_local() {
2441 if self.populated_external_types.borrow().contains(&type_id) {
2445 debug!("populate_inherent_implementations_for_type_if_necessary: searching for {:?}",
2448 let mut inherent_impls = Vec::new();
2449 csearch::each_inherent_implementation_for_type(&self.sess.cstore, type_id, |impl_def_id| {
2450 // Record the implementation.
2451 inherent_impls.push(impl_def_id);
2453 // Store the implementation info.
2454 let impl_items = csearch::get_impl_items(&self.sess.cstore, impl_def_id);
2455 self.impl_items.borrow_mut().insert(impl_def_id, impl_items);
2458 self.inherent_impls.borrow_mut().insert(type_id, Rc::new(inherent_impls));
2459 self.populated_external_types.borrow_mut().insert(type_id);
2462 /// Populates the type context with all the implementations for the given
2463 /// trait if necessary.
2464 pub fn populate_implementations_for_trait_if_necessary(&self, trait_id: DefId) {
2465 if trait_id.is_local() {
2469 let def = self.lookup_trait_def(trait_id);
2470 if def.flags.get().intersects(TraitFlags::IMPLS_VALID) {
2474 debug!("populate_implementations_for_trait_if_necessary: searching for {:?}", def);
2476 if csearch::is_defaulted_trait(&self.sess.cstore, trait_id) {
2477 self.record_trait_has_default_impl(trait_id);
2480 csearch::each_implementation_for_trait(&self.sess.cstore, trait_id, |impl_def_id| {
2481 let impl_items = csearch::get_impl_items(&self.sess.cstore, impl_def_id);
2482 let trait_ref = self.impl_trait_ref(impl_def_id).unwrap();
2483 // Record the trait->implementation mapping.
2484 def.record_impl(self, impl_def_id, trait_ref);
2486 // For any methods that use a default implementation, add them to
2487 // the map. This is a bit unfortunate.
2488 for impl_item_def_id in &impl_items {
2489 let method_def_id = impl_item_def_id.def_id();
2490 match self.impl_or_trait_item(method_def_id) {
2491 MethodTraitItem(method) => {
2492 if let Some(source) = method.provided_source {
2493 self.provided_method_sources
2495 .insert(method_def_id, source);
2502 // Store the implementation info.
2503 self.impl_items.borrow_mut().insert(impl_def_id, impl_items);
2506 def.flags.set(def.flags.get() | TraitFlags::IMPLS_VALID);
2509 /// Given the def_id of an impl, return the def_id of the trait it implements.
2510 /// If it implements no trait, return `None`.
2511 pub fn trait_id_of_impl(&self, def_id: DefId) -> Option<DefId> {
2512 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2515 /// If the given def ID describes a method belonging to an impl, return the
2516 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2517 pub fn impl_of_method(&self, def_id: DefId) -> Option<DefId> {
2518 if def_id.krate != LOCAL_CRATE {
2519 return match csearch::get_impl_or_trait_item(self,
2520 def_id).container() {
2521 TraitContainer(_) => None,
2522 ImplContainer(def_id) => Some(def_id),
2525 match self.impl_or_trait_items.borrow().get(&def_id).cloned() {
2526 Some(trait_item) => {
2527 match trait_item.container() {
2528 TraitContainer(_) => None,
2529 ImplContainer(def_id) => Some(def_id),
2536 /// If the given def ID describes an item belonging to a trait (either a
2537 /// default method or an implementation of a trait method), return the ID of
2538 /// the trait that the method belongs to. Otherwise, return `None`.
2539 pub fn trait_of_item(&self, def_id: DefId) -> Option<DefId> {
2540 if def_id.krate != LOCAL_CRATE {
2541 return csearch::get_trait_of_item(&self.sess.cstore, def_id, self);
2543 match self.impl_or_trait_items.borrow().get(&def_id).cloned() {
2544 Some(impl_or_trait_item) => {
2545 match impl_or_trait_item.container() {
2546 TraitContainer(def_id) => Some(def_id),
2547 ImplContainer(def_id) => self.trait_id_of_impl(def_id),
2554 /// If the given def ID describes an item belonging to a trait, (either a
2555 /// default method or an implementation of a trait method), return the ID of
2556 /// the method inside trait definition (this means that if the given def ID
2557 /// is already that of the original trait method, then the return value is
2559 /// Otherwise, return `None`.
2560 pub fn trait_item_of_item(&self, def_id: DefId) -> Option<ImplOrTraitItemId> {
2561 let impl_item = match self.impl_or_trait_items.borrow().get(&def_id) {
2562 Some(m) => m.clone(),
2563 None => return None,
2565 let name = impl_item.name();
2566 match self.trait_of_item(def_id) {
2567 Some(trait_did) => {
2568 self.trait_items(trait_did).iter()
2569 .find(|item| item.name() == name)
2570 .map(|item| item.id())
2576 /// Construct a parameter environment suitable for static contexts or other contexts where there
2577 /// are no free type/lifetime parameters in scope.
2578 pub fn empty_parameter_environment<'a>(&'a self)
2579 -> ParameterEnvironment<'a,'tcx> {
2580 ty::ParameterEnvironment { tcx: self,
2581 free_substs: Substs::empty(),
2582 caller_bounds: Vec::new(),
2583 implicit_region_bound: ty::ReEmpty,
2584 selection_cache: traits::SelectionCache::new(),
2586 // for an empty parameter
2587 // environment, there ARE no free
2588 // regions, so it shouldn't matter
2589 // what we use for the free id
2590 free_id: ast::DUMMY_NODE_ID }
2593 /// Constructs and returns a substitution that can be applied to move from
2594 /// the "outer" view of a type or method to the "inner" view.
2595 /// In general, this means converting from bound parameters to
2596 /// free parameters. Since we currently represent bound/free type
2597 /// parameters in the same way, this only has an effect on regions.
2598 pub fn construct_free_substs(&self, generics: &Generics<'tcx>,
2599 free_id: NodeId) -> Substs<'tcx> {
2601 let mut types = VecPerParamSpace::empty();
2602 for def in generics.types.as_slice() {
2603 debug!("construct_parameter_environment(): push_types_from_defs: def={:?}",
2605 types.push(def.space, self.mk_param_from_def(def));
2608 let free_id_outlive = self.region_maps.item_extent(free_id);
2610 // map bound 'a => free 'a
2611 let mut regions = VecPerParamSpace::empty();
2612 for def in generics.regions.as_slice() {
2614 ReFree(FreeRegion { scope: free_id_outlive,
2615 bound_region: BrNamed(def.def_id, def.name) });
2616 debug!("push_region_params {:?}", region);
2617 regions.push(def.space, region);
2622 regions: subst::NonerasedRegions(regions)
2626 /// See `ParameterEnvironment` struct def'n for details
2627 pub fn construct_parameter_environment<'a>(&'a self,
2629 generics: &ty::Generics<'tcx>,
2630 generic_predicates: &ty::GenericPredicates<'tcx>,
2632 -> ParameterEnvironment<'a, 'tcx>
2635 // Construct the free substs.
2638 let free_substs = self.construct_free_substs(generics, free_id);
2639 let free_id_outlive = self.region_maps.item_extent(free_id);
2642 // Compute the bounds on Self and the type parameters.
2645 let bounds = generic_predicates.instantiate(self, &free_substs);
2646 let bounds = self.liberate_late_bound_regions(free_id_outlive, &ty::Binder(bounds));
2647 let predicates = bounds.predicates.into_vec();
2649 debug!("construct_parameter_environment: free_id={:?} free_subst={:?} predicates={:?}",
2655 // Finally, we have to normalize the bounds in the environment, in
2656 // case they contain any associated type projections. This process
2657 // can yield errors if the put in illegal associated types, like
2658 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2659 // report these errors right here; this doesn't actually feel
2660 // right to me, because constructing the environment feels like a
2661 // kind of a "idempotent" action, but I'm not sure where would be
2662 // a better place. In practice, we construct environments for
2663 // every fn once during type checking, and we'll abort if there
2664 // are any errors at that point, so after type checking you can be
2665 // sure that this will succeed without errors anyway.
2668 let unnormalized_env = ty::ParameterEnvironment {
2670 free_substs: free_substs,
2671 implicit_region_bound: ty::ReScope(free_id_outlive),
2672 caller_bounds: predicates,
2673 selection_cache: traits::SelectionCache::new(),
2677 let cause = traits::ObligationCause::misc(span, free_id);
2678 traits::normalize_param_env_or_error(unnormalized_env, cause)
2681 pub fn is_method_call(&self, expr_id: NodeId) -> bool {
2682 self.tables.borrow().method_map.contains_key(&MethodCall::expr(expr_id))
2685 pub fn is_overloaded_autoderef(&self, expr_id: NodeId, autoderefs: u32) -> bool {
2686 self.tables.borrow().method_map.contains_key(&MethodCall::autoderef(expr_id,
2690 pub fn upvar_capture(&self, upvar_id: ty::UpvarId) -> Option<ty::UpvarCapture> {
2691 Some(self.tables.borrow().upvar_capture_map.get(&upvar_id).unwrap().clone())
2695 /// The category of explicit self.
2696 #[derive(Clone, Copy, Eq, PartialEq, Debug)]
2697 pub enum ExplicitSelfCategory {
2698 StaticExplicitSelfCategory,
2699 ByValueExplicitSelfCategory,
2700 ByReferenceExplicitSelfCategory(Region, hir::Mutability),
2701 ByBoxExplicitSelfCategory,
2704 /// A free variable referred to in a function.
2705 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
2706 pub struct Freevar {
2707 /// The variable being accessed free.
2710 // First span where it is accessed (there can be multiple).
2714 pub type FreevarMap = NodeMap<Vec<Freevar>>;
2716 pub type CaptureModeMap = NodeMap<hir::CaptureClause>;
2718 // Trait method resolution
2719 pub type TraitMap = NodeMap<Vec<DefId>>;
2721 // Map from the NodeId of a glob import to a list of items which are actually
2723 pub type GlobMap = HashMap<NodeId, HashSet<Name>>;
2725 impl<'tcx> ctxt<'tcx> {
2726 pub fn with_freevars<T, F>(&self, fid: NodeId, f: F) -> T where
2727 F: FnOnce(&[Freevar]) -> T,
2729 match self.freevars.borrow().get(&fid) {
2731 Some(d) => f(&d[..])
2735 pub fn make_substs_for_receiver_types(&self,
2736 trait_ref: &ty::TraitRef<'tcx>,
2737 method: &ty::Method<'tcx>)
2738 -> subst::Substs<'tcx>
2741 * Substitutes the values for the receiver's type parameters
2742 * that are found in method, leaving the method's type parameters
2746 let meth_tps: Vec<Ty> =
2747 method.generics.types.get_slice(subst::FnSpace)
2749 .map(|def| self.mk_param_from_def(def))
2751 let meth_regions: Vec<ty::Region> =
2752 method.generics.regions.get_slice(subst::FnSpace)
2754 .map(|def| def.to_early_bound_region())
2756 trait_ref.substs.clone().with_method(meth_tps, meth_regions)
2760 /// An "escaping region" is a bound region whose binder is not part of `t`.
2762 /// So, for example, consider a type like the following, which has two binders:
2764 /// for<'a> fn(x: for<'b> fn(&'a isize, &'b isize))
2765 /// ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ outer scope
2766 /// ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ inner scope
2768 /// This type has *bound regions* (`'a`, `'b`), but it does not have escaping regions, because the
2769 /// binders of both `'a` and `'b` are part of the type itself. However, if we consider the *inner
2770 /// fn type*, that type has an escaping region: `'a`.
2772 /// Note that what I'm calling an "escaping region" is often just called a "free region". However,
2773 /// we already use the term "free region". It refers to the regions that we use to represent bound
2774 /// regions on a fn definition while we are typechecking its body.
2776 /// To clarify, conceptually there is no particular difference between an "escaping" region and a
2777 /// "free" region. However, there is a big difference in practice. Basically, when "entering" a
2778 /// binding level, one is generally required to do some sort of processing to a bound region, such
2779 /// as replacing it with a fresh/skolemized region, or making an entry in the environment to
2780 /// represent the scope to which it is attached, etc. An escaping region represents a bound region
2781 /// for which this processing has not yet been done.
2782 pub trait RegionEscape {
2783 fn has_escaping_regions(&self) -> bool {
2784 self.has_regions_escaping_depth(0)
2787 fn has_regions_escaping_depth(&self, depth: u32) -> bool;
2790 pub trait HasTypeFlags {
2791 fn has_type_flags(&self, flags: TypeFlags) -> bool;
2792 fn has_projection_types(&self) -> bool {
2793 self.has_type_flags(TypeFlags::HAS_PROJECTION)
2795 fn references_error(&self) -> bool {
2796 self.has_type_flags(TypeFlags::HAS_TY_ERR)
2798 fn has_param_types(&self) -> bool {
2799 self.has_type_flags(TypeFlags::HAS_PARAMS)
2801 fn has_self_ty(&self) -> bool {
2802 self.has_type_flags(TypeFlags::HAS_SELF)
2804 fn has_infer_types(&self) -> bool {
2805 self.has_type_flags(TypeFlags::HAS_TY_INFER)
2807 fn needs_infer(&self) -> bool {
2808 self.has_type_flags(TypeFlags::HAS_TY_INFER | TypeFlags::HAS_RE_INFER)
2810 fn needs_subst(&self) -> bool {
2811 self.has_type_flags(TypeFlags::NEEDS_SUBST)
2813 fn has_closure_types(&self) -> bool {
2814 self.has_type_flags(TypeFlags::HAS_TY_CLOSURE)
2816 fn has_erasable_regions(&self) -> bool {
2817 self.has_type_flags(TypeFlags::HAS_RE_EARLY_BOUND |
2818 TypeFlags::HAS_RE_INFER |
2819 TypeFlags::HAS_FREE_REGIONS)
2821 /// Indicates whether this value references only 'global'
2822 /// types/lifetimes that are the same regardless of what fn we are
2823 /// in. This is used for caching. Errs on the side of returning
2825 fn is_global(&self) -> bool {
2826 !self.has_type_flags(TypeFlags::HAS_LOCAL_NAMES)