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 to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
984 Predicate::Trait(ref t) => {
985 Some(t.to_poly_trait_ref())
987 Predicate::Projection(..) |
988 Predicate::Equate(..) |
989 Predicate::RegionOutlives(..) |
990 Predicate::WellFormed(..) |
991 Predicate::ObjectSafe(..) |
992 Predicate::TypeOutlives(..) => {
999 /// Represents the bounds declared on a particular set of type
1000 /// parameters. Should eventually be generalized into a flag list of
1001 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1002 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1003 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1004 /// the `GenericPredicates` are expressed in terms of the bound type
1005 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1006 /// represented a set of bounds for some particular instantiation,
1007 /// meaning that the generic parameters have been substituted with
1012 /// struct Foo<T,U:Bar<T>> { ... }
1014 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1015 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1016 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1017 /// [usize:Bar<isize>]]`.
1019 pub struct InstantiatedPredicates<'tcx> {
1020 pub predicates: VecPerParamSpace<Predicate<'tcx>>,
1023 impl<'tcx> InstantiatedPredicates<'tcx> {
1024 pub fn empty() -> InstantiatedPredicates<'tcx> {
1025 InstantiatedPredicates { predicates: VecPerParamSpace::empty() }
1028 pub fn is_empty(&self) -> bool {
1029 self.predicates.is_empty()
1033 impl<'tcx> TraitRef<'tcx> {
1034 pub fn new(def_id: DefId, substs: &'tcx Substs<'tcx>) -> TraitRef<'tcx> {
1035 TraitRef { def_id: def_id, substs: substs }
1038 pub fn self_ty(&self) -> Ty<'tcx> {
1039 self.substs.self_ty().unwrap()
1042 pub fn input_types(&self) -> &[Ty<'tcx>] {
1043 // Select only the "input types" from a trait-reference. For
1044 // now this is all the types that appear in the
1045 // trait-reference, but it should eventually exclude
1046 // associated types.
1047 self.substs.types.as_slice()
1051 /// When type checking, we use the `ParameterEnvironment` to track
1052 /// details about the type/lifetime parameters that are in scope.
1053 /// It primarily stores the bounds information.
1055 /// Note: This information might seem to be redundant with the data in
1056 /// `tcx.ty_param_defs`, but it is not. That table contains the
1057 /// parameter definitions from an "outside" perspective, but this
1058 /// struct will contain the bounds for a parameter as seen from inside
1059 /// the function body. Currently the only real distinction is that
1060 /// bound lifetime parameters are replaced with free ones, but in the
1061 /// future I hope to refine the representation of types so as to make
1062 /// more distinctions clearer.
1064 pub struct ParameterEnvironment<'a, 'tcx:'a> {
1065 pub tcx: &'a ctxt<'tcx>,
1067 /// See `construct_free_substs` for details.
1068 pub free_substs: Substs<'tcx>,
1070 /// Each type parameter has an implicit region bound that
1071 /// indicates it must outlive at least the function body (the user
1072 /// may specify stronger requirements). This field indicates the
1073 /// region of the callee.
1074 pub implicit_region_bound: ty::Region,
1076 /// Obligations that the caller must satisfy. This is basically
1077 /// the set of bounds on the in-scope type parameters, translated
1078 /// into Obligations, and elaborated and normalized.
1079 pub caller_bounds: Vec<ty::Predicate<'tcx>>,
1081 /// Caches the results of trait selection. This cache is used
1082 /// for things that have to do with the parameters in scope.
1083 pub selection_cache: traits::SelectionCache<'tcx>,
1085 /// Scope that is attached to free regions for this scope. This
1086 /// is usually the id of the fn body, but for more abstract scopes
1087 /// like structs we often use the node-id of the struct.
1089 /// FIXME(#3696). It would be nice to refactor so that free
1090 /// regions don't have this implicit scope and instead introduce
1091 /// relationships in the environment.
1092 pub free_id: ast::NodeId,
1095 impl<'a, 'tcx> ParameterEnvironment<'a, 'tcx> {
1096 pub fn with_caller_bounds(&self,
1097 caller_bounds: Vec<ty::Predicate<'tcx>>)
1098 -> ParameterEnvironment<'a,'tcx>
1100 ParameterEnvironment {
1102 free_substs: self.free_substs.clone(),
1103 implicit_region_bound: self.implicit_region_bound,
1104 caller_bounds: caller_bounds,
1105 selection_cache: traits::SelectionCache::new(),
1106 free_id: self.free_id,
1110 pub fn for_item(cx: &'a ctxt<'tcx>, id: NodeId) -> ParameterEnvironment<'a, 'tcx> {
1111 match cx.map.find(id) {
1112 Some(ast_map::NodeImplItem(ref impl_item)) => {
1113 match impl_item.node {
1114 hir::TypeImplItem(_) => {
1115 // associated types don't have their own entry (for some reason),
1116 // so for now just grab environment for the impl
1117 let impl_id = cx.map.get_parent(id);
1118 let impl_def_id = DefId::local(impl_id);
1119 let scheme = cx.lookup_item_type(impl_def_id);
1120 let predicates = cx.lookup_predicates(impl_def_id);
1121 cx.construct_parameter_environment(impl_item.span,
1126 hir::ConstImplItem(_, _) => {
1127 let def_id = DefId::local(id);
1128 let scheme = cx.lookup_item_type(def_id);
1129 let predicates = cx.lookup_predicates(def_id);
1130 cx.construct_parameter_environment(impl_item.span,
1135 hir::MethodImplItem(_, ref body) => {
1136 let method_def_id = DefId::local(id);
1137 match cx.impl_or_trait_item(method_def_id) {
1138 MethodTraitItem(ref method_ty) => {
1139 let method_generics = &method_ty.generics;
1140 let method_bounds = &method_ty.predicates;
1141 cx.construct_parameter_environment(
1149 .bug("ParameterEnvironment::for_item(): \
1150 got non-method item from impl method?!")
1156 Some(ast_map::NodeTraitItem(trait_item)) => {
1157 match trait_item.node {
1158 hir::TypeTraitItem(..) => {
1159 // associated types don't have their own entry (for some reason),
1160 // so for now just grab environment for the trait
1161 let trait_id = cx.map.get_parent(id);
1162 let trait_def_id = DefId::local(trait_id);
1163 let trait_def = cx.lookup_trait_def(trait_def_id);
1164 let predicates = cx.lookup_predicates(trait_def_id);
1165 cx.construct_parameter_environment(trait_item.span,
1166 &trait_def.generics,
1170 hir::ConstTraitItem(..) => {
1171 let def_id = DefId::local(id);
1172 let scheme = cx.lookup_item_type(def_id);
1173 let predicates = cx.lookup_predicates(def_id);
1174 cx.construct_parameter_environment(trait_item.span,
1179 hir::MethodTraitItem(_, ref body) => {
1180 // for the body-id, use the id of the body
1181 // block, unless this is a trait method with
1182 // no default, then fallback to the method id.
1183 let body_id = body.as_ref().map(|b| b.id).unwrap_or(id);
1184 let method_def_id = DefId::local(id);
1186 match cx.impl_or_trait_item(method_def_id) {
1187 MethodTraitItem(ref method_ty) => {
1188 let method_generics = &method_ty.generics;
1189 let method_bounds = &method_ty.predicates;
1190 cx.construct_parameter_environment(
1198 .bug("ParameterEnvironment::for_item(): \
1199 got non-method item from provided \
1206 Some(ast_map::NodeItem(item)) => {
1208 hir::ItemFn(_, _, _, _, _, ref body) => {
1209 // We assume this is a function.
1210 let fn_def_id = DefId::local(id);
1211 let fn_scheme = cx.lookup_item_type(fn_def_id);
1212 let fn_predicates = cx.lookup_predicates(fn_def_id);
1214 cx.construct_parameter_environment(item.span,
1215 &fn_scheme.generics,
1220 hir::ItemStruct(..) |
1222 hir::ItemConst(..) |
1223 hir::ItemStatic(..) => {
1224 let def_id = DefId::local(id);
1225 let scheme = cx.lookup_item_type(def_id);
1226 let predicates = cx.lookup_predicates(def_id);
1227 cx.construct_parameter_environment(item.span,
1232 hir::ItemTrait(..) => {
1233 let def_id = DefId::local(id);
1234 let trait_def = cx.lookup_trait_def(def_id);
1235 let predicates = cx.lookup_predicates(def_id);
1236 cx.construct_parameter_environment(item.span,
1237 &trait_def.generics,
1242 cx.sess.span_bug(item.span,
1243 "ParameterEnvironment::from_item():
1244 can't create a parameter \
1245 environment for this kind of item")
1249 Some(ast_map::NodeExpr(..)) => {
1250 // This is a convenience to allow closures to work.
1251 ParameterEnvironment::for_item(cx, cx.map.get_parent(id))
1254 cx.sess.bug(&format!("ParameterEnvironment::from_item(): \
1255 `{}` is not an item",
1256 cx.map.node_to_string(id)))
1262 /// A "type scheme", in ML terminology, is a type combined with some
1263 /// set of generic types that the type is, well, generic over. In Rust
1264 /// terms, it is the "type" of a fn item or struct -- this type will
1265 /// include various generic parameters that must be substituted when
1266 /// the item/struct is referenced. That is called converting the type
1267 /// scheme to a monotype.
1269 /// - `generics`: the set of type parameters and their bounds
1270 /// - `ty`: the base types, which may reference the parameters defined
1273 /// Note that TypeSchemes are also sometimes called "polytypes" (and
1274 /// in fact this struct used to carry that name, so you may find some
1275 /// stray references in a comment or something). We try to reserve the
1276 /// "poly" prefix to refer to higher-ranked things, as in
1279 /// Note that each item also comes with predicates, see
1280 /// `lookup_predicates`.
1281 #[derive(Clone, Debug)]
1282 pub struct TypeScheme<'tcx> {
1283 pub generics: Generics<'tcx>,
1288 flags TraitFlags: u32 {
1289 const NO_TRAIT_FLAGS = 0,
1290 const HAS_DEFAULT_IMPL = 1 << 0,
1291 const IS_OBJECT_SAFE = 1 << 1,
1292 const OBJECT_SAFETY_VALID = 1 << 2,
1293 const IMPLS_VALID = 1 << 3,
1297 /// As `TypeScheme` but for a trait ref.
1298 pub struct TraitDef<'tcx> {
1299 pub unsafety: hir::Unsafety,
1301 /// If `true`, then this trait had the `#[rustc_paren_sugar]`
1302 /// attribute, indicating that it should be used with `Foo()`
1303 /// sugar. This is a temporary thing -- eventually any trait wil
1304 /// be usable with the sugar (or without it).
1305 pub paren_sugar: bool,
1307 /// Generic type definitions. Note that `Self` is listed in here
1308 /// as having a single bound, the trait itself (e.g., in the trait
1309 /// `Eq`, there is a single bound `Self : Eq`). This is so that
1310 /// default methods get to assume that the `Self` parameters
1311 /// implements the trait.
1312 pub generics: Generics<'tcx>,
1314 pub trait_ref: TraitRef<'tcx>,
1316 /// A list of the associated types defined in this trait. Useful
1317 /// for resolving `X::Foo` type markers.
1318 pub associated_type_names: Vec<Name>,
1320 // Impls of this trait. To allow for quicker lookup, the impls are indexed
1321 // by a simplified version of their Self type: impls with a simplifiable
1322 // Self are stored in nonblanket_impls keyed by it, while all other impls
1323 // are stored in blanket_impls.
1325 /// Impls of the trait.
1326 pub nonblanket_impls: RefCell<
1327 FnvHashMap<fast_reject::SimplifiedType, Vec<DefId>>
1330 /// Blanket impls associated with the trait.
1331 pub blanket_impls: RefCell<Vec<DefId>>,
1334 pub flags: Cell<TraitFlags>
1337 impl<'tcx> TraitDef<'tcx> {
1338 // returns None if not yet calculated
1339 pub fn object_safety(&self) -> Option<bool> {
1340 if self.flags.get().intersects(TraitFlags::OBJECT_SAFETY_VALID) {
1341 Some(self.flags.get().intersects(TraitFlags::IS_OBJECT_SAFE))
1347 pub fn set_object_safety(&self, is_safe: bool) {
1348 assert!(self.object_safety().map(|cs| cs == is_safe).unwrap_or(true));
1350 self.flags.get() | if is_safe {
1351 TraitFlags::OBJECT_SAFETY_VALID | TraitFlags::IS_OBJECT_SAFE
1353 TraitFlags::OBJECT_SAFETY_VALID
1358 /// Records a trait-to-implementation mapping.
1359 pub fn record_impl(&self,
1362 impl_trait_ref: TraitRef<'tcx>) {
1363 debug!("TraitDef::record_impl for {:?}, from {:?}",
1364 self, impl_trait_ref);
1366 // We don't want to borrow_mut after we already populated all impls,
1367 // so check if an impl is present with an immutable borrow first.
1368 if let Some(sty) = fast_reject::simplify_type(tcx,
1369 impl_trait_ref.self_ty(), false) {
1370 if let Some(is) = self.nonblanket_impls.borrow().get(&sty) {
1371 if is.contains(&impl_def_id) {
1372 return // duplicate - skip
1376 self.nonblanket_impls.borrow_mut().entry(sty).or_insert(vec![]).push(impl_def_id)
1378 if self.blanket_impls.borrow().contains(&impl_def_id) {
1379 return // duplicate - skip
1381 self.blanket_impls.borrow_mut().push(impl_def_id)
1386 pub fn for_each_impl<F: FnMut(DefId)>(&self, tcx: &ctxt<'tcx>, mut f: F) {
1387 tcx.populate_implementations_for_trait_if_necessary(self.trait_ref.def_id);
1389 for &impl_def_id in self.blanket_impls.borrow().iter() {
1393 for v in self.nonblanket_impls.borrow().values() {
1394 for &impl_def_id in v {
1400 /// Iterate over every impl that could possibly match the
1401 /// self-type `self_ty`.
1402 pub fn for_each_relevant_impl<F: FnMut(DefId)>(&self,
1407 tcx.populate_implementations_for_trait_if_necessary(self.trait_ref.def_id);
1409 for &impl_def_id in self.blanket_impls.borrow().iter() {
1413 // simplify_type(.., false) basically replaces type parameters and
1414 // projections with infer-variables. This is, of course, done on
1415 // the impl trait-ref when it is instantiated, but not on the
1416 // predicate trait-ref which is passed here.
1418 // for example, if we match `S: Copy` against an impl like
1419 // `impl<T:Copy> Copy for Option<T>`, we replace the type variable
1420 // in `Option<T>` with an infer variable, to `Option<_>` (this
1421 // doesn't actually change fast_reject output), but we don't
1422 // replace `S` with anything - this impl of course can't be
1423 // selected, and as there are hundreds of similar impls,
1424 // considering them would significantly harm performance.
1425 if let Some(simp) = fast_reject::simplify_type(tcx, self_ty, true) {
1426 if let Some(impls) = self.nonblanket_impls.borrow().get(&simp) {
1427 for &impl_def_id in impls {
1432 for v in self.nonblanket_impls.borrow().values() {
1433 for &impl_def_id in v {
1443 flags AdtFlags: u32 {
1444 const NO_ADT_FLAGS = 0,
1445 const IS_ENUM = 1 << 0,
1446 const IS_DTORCK = 1 << 1, // is this a dtorck type?
1447 const IS_DTORCK_VALID = 1 << 2,
1448 const IS_PHANTOM_DATA = 1 << 3,
1449 const IS_SIMD = 1 << 4,
1450 const IS_FUNDAMENTAL = 1 << 5,
1451 const IS_NO_DROP_FLAG = 1 << 6,
1455 pub type AdtDef<'tcx> = &'tcx AdtDefData<'tcx, 'static>;
1456 pub type VariantDef<'tcx> = &'tcx VariantDefData<'tcx, 'static>;
1457 pub type FieldDef<'tcx> = &'tcx FieldDefData<'tcx, 'static>;
1459 // See comment on AdtDefData for explanation
1460 pub type AdtDefMaster<'tcx> = &'tcx AdtDefData<'tcx, 'tcx>;
1461 pub type VariantDefMaster<'tcx> = &'tcx VariantDefData<'tcx, 'tcx>;
1462 pub type FieldDefMaster<'tcx> = &'tcx FieldDefData<'tcx, 'tcx>;
1464 pub struct VariantDefData<'tcx, 'container: 'tcx> {
1466 pub name: Name, // struct's name if this is a struct
1468 pub fields: Vec<FieldDefData<'tcx, 'container>>
1471 pub struct FieldDefData<'tcx, 'container: 'tcx> {
1472 /// The field's DefId. NOTE: the fields of tuple-like enum variants
1473 /// are not real items, and don't have entries in tcache etc.
1475 /// special_idents::unnamed_field.name
1476 /// if this is a tuple-like field
1478 pub vis: hir::Visibility,
1479 /// TyIVar is used here to allow for variance (see the doc at
1481 ty: ivar::TyIVar<'tcx, 'container>
1484 /// The definition of an abstract data type - a struct or enum.
1486 /// These are all interned (by intern_adt_def) into the adt_defs
1489 /// Because of the possibility of nested tcx-s, this type
1490 /// needs 2 lifetimes: the traditional variant lifetime ('tcx)
1491 /// bounding the lifetime of the inner types is of course necessary.
1492 /// However, it is not sufficient - types from a child tcx must
1493 /// not be leaked into the master tcx by being stored in an AdtDefData.
1495 /// The 'container lifetime ensures that by outliving the container
1496 /// tcx and preventing shorter-lived types from being inserted. When
1497 /// write access is not needed, the 'container lifetime can be
1498 /// erased to 'static, which can be done by the AdtDef wrapper.
1499 pub struct AdtDefData<'tcx, 'container: 'tcx> {
1501 pub variants: Vec<VariantDefData<'tcx, 'container>>,
1502 destructor: Cell<Option<DefId>>,
1503 flags: Cell<AdtFlags>,
1506 impl<'tcx, 'container> PartialEq for AdtDefData<'tcx, 'container> {
1507 // AdtDefData are always interned and this is part of TyS equality
1509 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1512 impl<'tcx, 'container> Eq for AdtDefData<'tcx, 'container> {}
1514 impl<'tcx, 'container> Hash for AdtDefData<'tcx, 'container> {
1516 fn hash<H: Hasher>(&self, s: &mut H) {
1517 (self as *const AdtDefData).hash(s)
1522 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1523 pub enum AdtKind { Struct, Enum }
1525 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1526 pub enum VariantKind { Dict, Tuple, Unit }
1528 impl<'tcx, 'container> AdtDefData<'tcx, 'container> {
1529 fn new(tcx: &ctxt<'tcx>,
1532 variants: Vec<VariantDefData<'tcx, 'container>>) -> Self {
1533 let mut flags = AdtFlags::NO_ADT_FLAGS;
1534 let attrs = tcx.get_attrs(did);
1535 if attr::contains_name(&attrs, "fundamental") {
1536 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1538 if attr::contains_name(&attrs, "unsafe_no_drop_flag") {
1539 flags = flags | AdtFlags::IS_NO_DROP_FLAG;
1541 if tcx.lookup_simd(did) {
1542 flags = flags | AdtFlags::IS_SIMD;
1544 if Some(did) == tcx.lang_items.phantom_data() {
1545 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1547 if let AdtKind::Enum = kind {
1548 flags = flags | AdtFlags::IS_ENUM;
1553 flags: Cell::new(flags),
1554 destructor: Cell::new(None)
1558 fn calculate_dtorck(&'tcx self, tcx: &ctxt<'tcx>) {
1559 if tcx.is_adt_dtorck(self) {
1560 self.flags.set(self.flags.get() | AdtFlags::IS_DTORCK);
1562 self.flags.set(self.flags.get() | AdtFlags::IS_DTORCK_VALID)
1565 /// Returns the kind of the ADT - Struct or Enum.
1567 pub fn adt_kind(&self) -> AdtKind {
1568 if self.flags.get().intersects(AdtFlags::IS_ENUM) {
1575 /// Returns whether this is a dtorck type. If this returns
1576 /// true, this type being safe for destruction requires it to be
1577 /// alive; Otherwise, only the contents are required to be.
1579 pub fn is_dtorck(&'tcx self, tcx: &ctxt<'tcx>) -> bool {
1580 if !self.flags.get().intersects(AdtFlags::IS_DTORCK_VALID) {
1581 self.calculate_dtorck(tcx)
1583 self.flags.get().intersects(AdtFlags::IS_DTORCK)
1586 /// Returns whether this type is #[fundamental] for the purposes
1587 /// of coherence checking.
1589 pub fn is_fundamental(&self) -> bool {
1590 self.flags.get().intersects(AdtFlags::IS_FUNDAMENTAL)
1594 pub fn is_simd(&self) -> bool {
1595 self.flags.get().intersects(AdtFlags::IS_SIMD)
1598 /// Returns true if this is PhantomData<T>.
1600 pub fn is_phantom_data(&self) -> bool {
1601 self.flags.get().intersects(AdtFlags::IS_PHANTOM_DATA)
1604 /// Returns whether this type has a destructor.
1605 pub fn has_dtor(&self) -> bool {
1606 match self.dtor_kind() {
1608 TraitDtor(..) => true
1612 /// Asserts this is a struct and returns the struct's unique
1614 pub fn struct_variant(&self) -> &VariantDefData<'tcx, 'container> {
1615 assert!(self.adt_kind() == AdtKind::Struct);
1620 pub fn type_scheme(&self, tcx: &ctxt<'tcx>) -> TypeScheme<'tcx> {
1621 tcx.lookup_item_type(self.did)
1625 pub fn predicates(&self, tcx: &ctxt<'tcx>) -> GenericPredicates<'tcx> {
1626 tcx.lookup_predicates(self.did)
1629 /// Returns an iterator over all fields contained
1632 pub fn all_fields(&self) ->
1634 slice::Iter<VariantDefData<'tcx, 'container>>,
1635 slice::Iter<FieldDefData<'tcx, 'container>>,
1636 for<'s> fn(&'s VariantDefData<'tcx, 'container>)
1637 -> slice::Iter<'s, FieldDefData<'tcx, 'container>>
1639 self.variants.iter().flat_map(VariantDefData::fields_iter)
1643 pub fn is_empty(&self) -> bool {
1644 self.variants.is_empty()
1648 pub fn is_univariant(&self) -> bool {
1649 self.variants.len() == 1
1652 pub fn is_payloadfree(&self) -> bool {
1653 !self.variants.is_empty() &&
1654 self.variants.iter().all(|v| v.fields.is_empty())
1657 pub fn variant_with_id(&self, vid: DefId) -> &VariantDefData<'tcx, 'container> {
1660 .find(|v| v.did == vid)
1661 .expect("variant_with_id: unknown variant")
1664 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1667 .position(|v| v.did == vid)
1668 .expect("variant_index_with_id: unknown variant")
1671 pub fn variant_of_def(&self, def: def::Def) -> &VariantDefData<'tcx, 'container> {
1673 def::DefVariant(_, vid, _) => self.variant_with_id(vid),
1674 def::DefStruct(..) | def::DefTy(..) => self.struct_variant(),
1675 _ => panic!("unexpected def {:?} in variant_of_def", def)
1679 pub fn destructor(&self) -> Option<DefId> {
1680 self.destructor.get()
1683 pub fn set_destructor(&self, dtor: DefId) {
1684 assert!(self.destructor.get().is_none());
1685 self.destructor.set(Some(dtor));
1688 pub fn dtor_kind(&self) -> DtorKind {
1689 match self.destructor.get() {
1691 TraitDtor(!self.flags.get().intersects(AdtFlags::IS_NO_DROP_FLAG))
1698 impl<'tcx, 'container> VariantDefData<'tcx, 'container> {
1700 fn fields_iter(&self) -> slice::Iter<FieldDefData<'tcx, 'container>> {
1704 pub fn kind(&self) -> VariantKind {
1705 match self.fields.get(0) {
1706 None => VariantKind::Unit,
1707 Some(&FieldDefData { name, .. }) if name == special_idents::unnamed_field.name => {
1710 Some(_) => VariantKind::Dict
1714 pub fn is_tuple_struct(&self) -> bool {
1715 self.kind() == VariantKind::Tuple
1719 pub fn find_field_named(&self,
1721 -> Option<&FieldDefData<'tcx, 'container>> {
1722 self.fields.iter().find(|f| f.name == name)
1726 pub fn field_named(&self, name: ast::Name) -> &FieldDefData<'tcx, 'container> {
1727 self.find_field_named(name).unwrap()
1731 impl<'tcx, 'container> FieldDefData<'tcx, 'container> {
1732 pub fn new(did: DefId,
1734 vis: hir::Visibility) -> Self {
1739 ty: ivar::TyIVar::new()
1743 pub fn ty(&self, tcx: &ctxt<'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1744 self.unsubst_ty().subst(tcx, subst)
1747 pub fn unsubst_ty(&self) -> Ty<'tcx> {
1751 pub fn fulfill_ty(&self, ty: Ty<'container>) {
1752 self.ty.fulfill(ty);
1756 /// Records the substitutions used to translate the polytype for an
1757 /// item into the monotype of an item reference.
1759 pub struct ItemSubsts<'tcx> {
1760 pub substs: Substs<'tcx>,
1763 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Debug, RustcEncodable, RustcDecodable)]
1764 pub enum ClosureKind {
1765 // Warning: Ordering is significant here! The ordering is chosen
1766 // because the trait Fn is a subtrait of FnMut and so in turn, and
1767 // hence we order it so that Fn < FnMut < FnOnce.
1774 pub fn trait_did(&self, cx: &ctxt) -> DefId {
1775 let result = match *self {
1776 FnClosureKind => cx.lang_items.require(FnTraitLangItem),
1777 FnMutClosureKind => {
1778 cx.lang_items.require(FnMutTraitLangItem)
1780 FnOnceClosureKind => {
1781 cx.lang_items.require(FnOnceTraitLangItem)
1785 Ok(trait_did) => trait_did,
1786 Err(err) => cx.sess.fatal(&err[..]),
1790 /// True if this a type that impls this closure kind
1791 /// must also implement `other`.
1792 pub fn extends(self, other: ty::ClosureKind) -> bool {
1793 match (self, other) {
1794 (FnClosureKind, FnClosureKind) => true,
1795 (FnClosureKind, FnMutClosureKind) => true,
1796 (FnClosureKind, FnOnceClosureKind) => true,
1797 (FnMutClosureKind, FnMutClosureKind) => true,
1798 (FnMutClosureKind, FnOnceClosureKind) => true,
1799 (FnOnceClosureKind, FnOnceClosureKind) => true,
1805 impl<'tcx> TyS<'tcx> {
1806 /// Iterator that walks `self` and any types reachable from
1807 /// `self`, in depth-first order. Note that just walks the types
1808 /// that appear in `self`, it does not descend into the fields of
1809 /// structs or variants. For example:
1812 /// isize => { isize }
1813 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
1814 /// [isize] => { [isize], isize }
1816 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
1817 TypeWalker::new(self)
1820 /// Iterator that walks the immediate children of `self`. Hence
1821 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
1822 /// (but not `i32`, like `walk`).
1823 pub fn walk_shallow(&'tcx self) -> IntoIter<Ty<'tcx>> {
1824 walk::walk_shallow(self)
1827 /// Walks `ty` and any types appearing within `ty`, invoking the
1828 /// callback `f` on each type. If the callback returns false, then the
1829 /// children of the current type are ignored.
1831 /// Note: prefer `ty.walk()` where possible.
1832 pub fn maybe_walk<F>(&'tcx self, mut f: F)
1833 where F : FnMut(Ty<'tcx>) -> bool
1835 let mut walker = self.walk();
1836 while let Some(ty) = walker.next() {
1838 walker.skip_current_subtree();
1844 impl<'tcx> ItemSubsts<'tcx> {
1845 pub fn empty() -> ItemSubsts<'tcx> {
1846 ItemSubsts { substs: Substs::empty() }
1849 pub fn is_noop(&self) -> bool {
1850 self.substs.is_noop()
1854 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1855 pub enum LvaluePreference {
1860 impl LvaluePreference {
1861 pub fn from_mutbl(m: hir::Mutability) -> Self {
1863 hir::MutMutable => PreferMutLvalue,
1864 hir::MutImmutable => NoPreference,
1869 /// Helper for looking things up in the various maps that are populated during
1870 /// typeck::collect (e.g., `cx.impl_or_trait_items`, `cx.tcache`, etc). All of
1871 /// these share the pattern that if the id is local, it should have been loaded
1872 /// into the map by the `typeck::collect` phase. If the def-id is external,
1873 /// then we have to go consult the crate loading code (and cache the result for
1875 fn lookup_locally_or_in_crate_store<V, F>(descr: &str,
1877 map: &RefCell<DefIdMap<V>>,
1878 load_external: F) -> V where
1882 match map.borrow().get(&def_id).cloned() {
1883 Some(v) => { return v; }
1887 if def_id.is_local() {
1888 panic!("No def'n found for {:?} in tcx.{}", def_id, descr);
1890 let v = load_external();
1891 map.borrow_mut().insert(def_id, v.clone());
1896 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
1898 hir::MutMutable => MutBorrow,
1899 hir::MutImmutable => ImmBorrow,
1903 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
1904 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
1905 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
1907 pub fn to_mutbl_lossy(self) -> hir::Mutability {
1909 MutBorrow => hir::MutMutable,
1910 ImmBorrow => hir::MutImmutable,
1912 // We have no type corresponding to a unique imm borrow, so
1913 // use `&mut`. It gives all the capabilities of an `&uniq`
1914 // and hence is a safe "over approximation".
1915 UniqueImmBorrow => hir::MutMutable,
1919 pub fn to_user_str(&self) -> &'static str {
1921 MutBorrow => "mutable",
1922 ImmBorrow => "immutable",
1923 UniqueImmBorrow => "uniquely immutable",
1928 impl<'tcx> ctxt<'tcx> {
1929 pub fn node_id_to_type(&self, id: NodeId) -> Ty<'tcx> {
1930 match self.node_id_to_type_opt(id) {
1932 None => self.sess.bug(
1933 &format!("node_id_to_type: no type for node `{}`",
1934 self.map.node_to_string(id)))
1938 pub fn node_id_to_type_opt(&self, id: NodeId) -> Option<Ty<'tcx>> {
1939 self.tables.borrow().node_types.get(&id).cloned()
1942 pub fn node_id_item_substs(&self, id: NodeId) -> ItemSubsts<'tcx> {
1943 match self.tables.borrow().item_substs.get(&id) {
1944 None => ItemSubsts::empty(),
1945 Some(ts) => ts.clone(),
1949 // Returns the type of a pattern as a monotype. Like @expr_ty, this function
1950 // doesn't provide type parameter substitutions.
1951 pub fn pat_ty(&self, pat: &hir::Pat) -> Ty<'tcx> {
1952 self.node_id_to_type(pat.id)
1954 pub fn pat_ty_opt(&self, pat: &hir::Pat) -> Option<Ty<'tcx>> {
1955 self.node_id_to_type_opt(pat.id)
1958 // Returns the type of an expression as a monotype.
1960 // NB (1): This is the PRE-ADJUSTMENT TYPE for the expression. That is, in
1961 // some cases, we insert `AutoAdjustment` annotations such as auto-deref or
1962 // auto-ref. The type returned by this function does not consider such
1963 // adjustments. See `expr_ty_adjusted()` instead.
1965 // NB (2): This type doesn't provide type parameter substitutions; e.g. if you
1966 // ask for the type of "id" in "id(3)", it will return "fn(&isize) -> isize"
1967 // instead of "fn(ty) -> T with T = isize".
1968 pub fn expr_ty(&self, expr: &hir::Expr) -> Ty<'tcx> {
1969 self.node_id_to_type(expr.id)
1972 pub fn expr_ty_opt(&self, expr: &hir::Expr) -> Option<Ty<'tcx>> {
1973 self.node_id_to_type_opt(expr.id)
1976 /// Returns the type of `expr`, considering any `AutoAdjustment`
1977 /// entry recorded for that expression.
1979 /// It would almost certainly be better to store the adjusted ty in with
1980 /// the `AutoAdjustment`, but I opted not to do this because it would
1981 /// require serializing and deserializing the type and, although that's not
1982 /// hard to do, I just hate that code so much I didn't want to touch it
1983 /// unless it was to fix it properly, which seemed a distraction from the
1984 /// thread at hand! -nmatsakis
1985 pub fn expr_ty_adjusted(&self, expr: &hir::Expr) -> Ty<'tcx> {
1987 .adjust(self, expr.span, expr.id,
1988 self.tables.borrow().adjustments.get(&expr.id),
1990 self.tables.borrow().method_map.get(&method_call).map(|method| method.ty)
1994 pub fn expr_span(&self, id: NodeId) -> Span {
1995 match self.map.find(id) {
1996 Some(ast_map::NodeExpr(e)) => {
2000 self.sess.bug(&format!("Node id {} is not an expr: {:?}",
2004 self.sess.bug(&format!("Node id {} is not present \
2005 in the node map", id));
2010 pub fn local_var_name_str(&self, id: NodeId) -> InternedString {
2011 match self.map.find(id) {
2012 Some(ast_map::NodeLocal(pat)) => {
2014 hir::PatIdent(_, ref path1, _) => path1.node.name.as_str(),
2016 self.sess.bug(&format!("Variable id {} maps to {:?}, not local", id, pat));
2020 r => self.sess.bug(&format!("Variable id {} maps to {:?}, not local", id, r)),
2024 pub fn resolve_expr(&self, expr: &hir::Expr) -> def::Def {
2025 match self.def_map.borrow().get(&expr.id) {
2026 Some(def) => def.full_def(),
2028 self.sess.span_bug(expr.span, &format!(
2029 "no def-map entry for expr {}", expr.id));
2034 pub fn expr_is_lval(&self, expr: &hir::Expr) -> bool {
2036 hir::ExprPath(..) => {
2037 // We can't use resolve_expr here, as this needs to run on broken
2038 // programs. We don't need to through - associated items are all
2040 match self.def_map.borrow().get(&expr.id) {
2041 Some(&def::PathResolution {
2042 base_def: def::DefStatic(..), ..
2043 }) | Some(&def::PathResolution {
2044 base_def: def::DefUpvar(..), ..
2045 }) | Some(&def::PathResolution {
2046 base_def: def::DefLocal(..), ..
2053 None => self.sess.span_bug(expr.span, &format!(
2054 "no def for path {}", expr.id))
2058 hir::ExprUnary(hir::UnDeref, _) |
2059 hir::ExprField(..) |
2060 hir::ExprTupField(..) |
2061 hir::ExprIndex(..) => {
2066 hir::ExprMethodCall(..) |
2067 hir::ExprStruct(..) |
2068 hir::ExprRange(..) |
2071 hir::ExprMatch(..) |
2072 hir::ExprClosure(..) |
2073 hir::ExprBlock(..) |
2074 hir::ExprRepeat(..) |
2076 hir::ExprBreak(..) |
2077 hir::ExprAgain(..) |
2079 hir::ExprWhile(..) |
2081 hir::ExprAssign(..) |
2082 hir::ExprInlineAsm(..) |
2083 hir::ExprAssignOp(..) |
2085 hir::ExprUnary(..) |
2087 hir::ExprAddrOf(..) |
2088 hir::ExprBinary(..) |
2089 hir::ExprCast(..) => {
2093 hir::ExprParen(ref e) => self.expr_is_lval(e),
2097 pub fn provided_source(&self, id: DefId) -> Option<DefId> {
2098 self.provided_method_sources.borrow().get(&id).cloned()
2101 pub fn provided_trait_methods(&self, id: DefId) -> Vec<Rc<Method<'tcx>>> {
2103 if let ItemTrait(_, _, _, ref ms) = self.map.expect_item(id.node).node {
2104 ms.iter().filter_map(|ti| {
2105 if let hir::MethodTraitItem(_, Some(_)) = ti.node {
2106 match self.impl_or_trait_item(DefId::local(ti.id)) {
2107 MethodTraitItem(m) => Some(m),
2109 self.sess.bug("provided_trait_methods(): \
2110 non-method item found from \
2111 looking up provided method?!")
2119 self.sess.bug(&format!("provided_trait_methods: `{:?}` is not a trait", id))
2122 csearch::get_provided_trait_methods(self, id)
2126 pub fn associated_consts(&self, id: DefId) -> Vec<Rc<AssociatedConst<'tcx>>> {
2128 match self.map.expect_item(id.node).node {
2129 ItemTrait(_, _, _, ref tis) => {
2130 tis.iter().filter_map(|ti| {
2131 if let hir::ConstTraitItem(_, _) = ti.node {
2132 match self.impl_or_trait_item(DefId::local(ti.id)) {
2133 ConstTraitItem(ac) => Some(ac),
2135 self.sess.bug("associated_consts(): \
2136 non-const item found from \
2137 looking up a constant?!")
2145 ItemImpl(_, _, _, _, _, ref iis) => {
2146 iis.iter().filter_map(|ii| {
2147 if let hir::ConstImplItem(_, _) = ii.node {
2148 match self.impl_or_trait_item(DefId::local(ii.id)) {
2149 ConstTraitItem(ac) => Some(ac),
2151 self.sess.bug("associated_consts(): \
2152 non-const item found from \
2153 looking up a constant?!")
2162 self.sess.bug(&format!("associated_consts: `{:?}` is not a trait \
2167 csearch::get_associated_consts(self, id)
2171 pub fn trait_items(&self, trait_did: DefId) -> Rc<Vec<ImplOrTraitItem<'tcx>>> {
2172 let mut trait_items = self.trait_items_cache.borrow_mut();
2173 match trait_items.get(&trait_did).cloned() {
2174 Some(trait_items) => trait_items,
2176 let def_ids = self.trait_item_def_ids(trait_did);
2177 let items: Rc<Vec<ImplOrTraitItem>> =
2178 Rc::new(def_ids.iter()
2179 .map(|d| self.impl_or_trait_item(d.def_id()))
2181 trait_items.insert(trait_did, items.clone());
2187 pub fn trait_impl_polarity(&self, id: DefId) -> Option<hir::ImplPolarity> {
2189 match self.map.find(id.node) {
2190 Some(ast_map::NodeItem(item)) => {
2192 hir::ItemImpl(_, polarity, _, _, _, _) => Some(polarity),
2199 csearch::get_impl_polarity(self, id)
2203 pub fn custom_coerce_unsized_kind(&self, did: DefId) -> adjustment::CustomCoerceUnsized {
2204 memoized(&self.custom_coerce_unsized_kinds, did, |did: DefId| {
2205 let (kind, src) = if did.krate != LOCAL_CRATE {
2206 (csearch::get_custom_coerce_unsized_kind(self, did), "external")
2214 self.sess.bug(&format!("custom_coerce_unsized_kind: \
2215 {} impl `{}` is missing its kind",
2216 src, self.item_path_str(did)));
2222 pub fn impl_or_trait_item(&self, id: DefId) -> ImplOrTraitItem<'tcx> {
2223 lookup_locally_or_in_crate_store(
2224 "impl_or_trait_items", id, &self.impl_or_trait_items,
2225 || csearch::get_impl_or_trait_item(self, id))
2228 pub fn trait_item_def_ids(&self, id: DefId) -> Rc<Vec<ImplOrTraitItemId>> {
2229 lookup_locally_or_in_crate_store(
2230 "trait_item_def_ids", id, &self.trait_item_def_ids,
2231 || Rc::new(csearch::get_trait_item_def_ids(&self.sess.cstore, id)))
2234 /// Returns the trait-ref corresponding to a given impl, or None if it is
2235 /// an inherent impl.
2236 pub fn impl_trait_ref(&self, id: DefId) -> Option<TraitRef<'tcx>> {
2237 lookup_locally_or_in_crate_store(
2238 "impl_trait_refs", id, &self.impl_trait_refs,
2239 || csearch::get_impl_trait(self, id))
2242 /// Returns whether this DefId refers to an impl
2243 pub fn is_impl(&self, id: DefId) -> bool {
2245 if let Some(ast_map::NodeItem(
2246 &hir::Item { node: hir::ItemImpl(..), .. })) = self.map.find(id.node) {
2252 csearch::is_impl(&self.sess.cstore, id)
2256 pub fn trait_ref_to_def_id(&self, tr: &hir::TraitRef) -> DefId {
2257 self.def_map.borrow().get(&tr.ref_id).expect("no def-map entry for trait").def_id()
2260 pub fn item_path_str(&self, id: DefId) -> String {
2261 self.with_path(id, |path| ast_map::path_to_string(path))
2264 pub fn with_path<T, F>(&self, id: DefId, f: F) -> T where
2265 F: FnOnce(ast_map::PathElems) -> T,
2268 self.map.with_path(id.node, f)
2270 f(csearch::get_item_path(self, id).iter().cloned().chain(LinkedPath::empty()))
2274 pub fn item_name(&self, id: DefId) -> ast::Name {
2276 self.map.get_path_elem(id.node).name()
2278 csearch::get_item_name(self, id)
2282 // Register a given item type
2283 pub fn register_item_type(&self, did: DefId, ty: TypeScheme<'tcx>) {
2284 self.tcache.borrow_mut().insert(did, ty);
2287 // If the given item is in an external crate, looks up its type and adds it to
2288 // the type cache. Returns the type parameters and type.
2289 pub fn lookup_item_type(&self, did: DefId) -> TypeScheme<'tcx> {
2290 lookup_locally_or_in_crate_store(
2291 "tcache", did, &self.tcache,
2292 || csearch::get_type(self, did))
2295 /// Given the did of a trait, returns its canonical trait ref.
2296 pub fn lookup_trait_def(&self, did: DefId) -> &'tcx TraitDef<'tcx> {
2297 lookup_locally_or_in_crate_store(
2298 "trait_defs", did, &self.trait_defs,
2299 || self.alloc_trait_def(csearch::get_trait_def(self, did))
2303 /// Given the did of an ADT, return a master reference to its
2304 /// definition. Unless you are planning on fulfilling the ADT's fields,
2305 /// use lookup_adt_def instead.
2306 pub fn lookup_adt_def_master(&self, did: DefId) -> AdtDefMaster<'tcx> {
2307 lookup_locally_or_in_crate_store(
2308 "adt_defs", did, &self.adt_defs,
2309 || csearch::get_adt_def(self, did)
2313 /// Given the did of an ADT, return a reference to its definition.
2314 pub fn lookup_adt_def(&self, did: DefId) -> AdtDef<'tcx> {
2315 // when reverse-variance goes away, a transmute::<AdtDefMaster,AdtDef>
2316 // woud be needed here.
2317 self.lookup_adt_def_master(did)
2320 /// Return the list of all interned ADT definitions
2321 pub fn adt_defs(&self) -> Vec<AdtDef<'tcx>> {
2322 self.adt_defs.borrow().values().cloned().collect()
2325 /// Given the did of an item, returns its full set of predicates.
2326 pub fn lookup_predicates(&self, did: DefId) -> GenericPredicates<'tcx> {
2327 lookup_locally_or_in_crate_store(
2328 "predicates", did, &self.predicates,
2329 || csearch::get_predicates(self, did))
2332 /// Given the did of a trait, returns its superpredicates.
2333 pub fn lookup_super_predicates(&self, did: DefId) -> GenericPredicates<'tcx> {
2334 lookup_locally_or_in_crate_store(
2335 "super_predicates", did, &self.super_predicates,
2336 || csearch::get_super_predicates(self, did))
2339 /// Get the attributes of a definition.
2340 pub fn get_attrs(&self, did: DefId) -> Cow<'tcx, [hir::Attribute]> {
2342 Cow::Borrowed(self.map.attrs(did.node))
2344 Cow::Owned(csearch::get_item_attrs(&self.sess.cstore, did))
2348 /// Determine whether an item is annotated with an attribute
2349 pub fn has_attr(&self, did: DefId, attr: &str) -> bool {
2350 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2353 /// Determine whether an item is annotated with `#[repr(packed)]`
2354 pub fn lookup_packed(&self, did: DefId) -> bool {
2355 self.lookup_repr_hints(did).contains(&attr::ReprPacked)
2358 /// Determine whether an item is annotated with `#[simd]`
2359 pub fn lookup_simd(&self, did: DefId) -> bool {
2360 self.has_attr(did, "simd")
2361 || self.lookup_repr_hints(did).contains(&attr::ReprSimd)
2364 /// Obtain the representation annotation for a struct definition.
2365 pub fn lookup_repr_hints(&self, did: DefId) -> Rc<Vec<attr::ReprAttr>> {
2366 memoized(&self.repr_hint_cache, did, |did: DefId| {
2367 Rc::new(if did.is_local() {
2368 self.get_attrs(did).iter().flat_map(|meta| {
2369 attr::find_repr_attrs(self.sess.diagnostic(), meta).into_iter()
2372 csearch::get_repr_attrs(&self.sess.cstore, did)
2377 pub fn item_variances(&self, item_id: DefId) -> Rc<ItemVariances> {
2378 lookup_locally_or_in_crate_store(
2379 "item_variance_map", item_id, &self.item_variance_map,
2380 || Rc::new(csearch::get_item_variances(&self.sess.cstore, item_id)))
2383 pub fn trait_has_default_impl(&self, trait_def_id: DefId) -> bool {
2384 self.populate_implementations_for_trait_if_necessary(trait_def_id);
2386 let def = self.lookup_trait_def(trait_def_id);
2387 def.flags.get().intersects(TraitFlags::HAS_DEFAULT_IMPL)
2390 /// Records a trait-to-implementation mapping.
2391 pub fn record_trait_has_default_impl(&self, trait_def_id: DefId) {
2392 let def = self.lookup_trait_def(trait_def_id);
2393 def.flags.set(def.flags.get() | TraitFlags::HAS_DEFAULT_IMPL)
2396 /// Load primitive inherent implementations if necessary
2397 pub fn populate_implementations_for_primitive_if_necessary(&self,
2398 primitive_def_id: DefId) {
2399 if primitive_def_id.is_local() {
2403 if self.populated_external_primitive_impls.borrow().contains(&primitive_def_id) {
2407 debug!("populate_implementations_for_primitive_if_necessary: searching for {:?}",
2410 let impl_items = csearch::get_impl_items(&self.sess.cstore, primitive_def_id);
2412 // Store the implementation info.
2413 self.impl_items.borrow_mut().insert(primitive_def_id, impl_items);
2414 self.populated_external_primitive_impls.borrow_mut().insert(primitive_def_id);
2417 /// Populates the type context with all the inherent implementations for
2418 /// the given type if necessary.
2419 pub fn populate_inherent_implementations_for_type_if_necessary(&self,
2421 if type_id.is_local() {
2425 if self.populated_external_types.borrow().contains(&type_id) {
2429 debug!("populate_inherent_implementations_for_type_if_necessary: searching for {:?}",
2432 let mut inherent_impls = Vec::new();
2433 csearch::each_inherent_implementation_for_type(&self.sess.cstore, type_id, |impl_def_id| {
2434 // Record the implementation.
2435 inherent_impls.push(impl_def_id);
2437 // Store the implementation info.
2438 let impl_items = csearch::get_impl_items(&self.sess.cstore, impl_def_id);
2439 self.impl_items.borrow_mut().insert(impl_def_id, impl_items);
2442 self.inherent_impls.borrow_mut().insert(type_id, Rc::new(inherent_impls));
2443 self.populated_external_types.borrow_mut().insert(type_id);
2446 /// Populates the type context with all the implementations for the given
2447 /// trait if necessary.
2448 pub fn populate_implementations_for_trait_if_necessary(&self, trait_id: DefId) {
2449 if trait_id.is_local() {
2453 let def = self.lookup_trait_def(trait_id);
2454 if def.flags.get().intersects(TraitFlags::IMPLS_VALID) {
2458 debug!("populate_implementations_for_trait_if_necessary: searching for {:?}", def);
2460 if csearch::is_defaulted_trait(&self.sess.cstore, trait_id) {
2461 self.record_trait_has_default_impl(trait_id);
2464 csearch::each_implementation_for_trait(&self.sess.cstore, trait_id, |impl_def_id| {
2465 let impl_items = csearch::get_impl_items(&self.sess.cstore, impl_def_id);
2466 let trait_ref = self.impl_trait_ref(impl_def_id).unwrap();
2467 // Record the trait->implementation mapping.
2468 def.record_impl(self, impl_def_id, trait_ref);
2470 // For any methods that use a default implementation, add them to
2471 // the map. This is a bit unfortunate.
2472 for impl_item_def_id in &impl_items {
2473 let method_def_id = impl_item_def_id.def_id();
2474 match self.impl_or_trait_item(method_def_id) {
2475 MethodTraitItem(method) => {
2476 if let Some(source) = method.provided_source {
2477 self.provided_method_sources
2479 .insert(method_def_id, source);
2486 // Store the implementation info.
2487 self.impl_items.borrow_mut().insert(impl_def_id, impl_items);
2490 def.flags.set(def.flags.get() | TraitFlags::IMPLS_VALID);
2493 /// Given the def_id of an impl, return the def_id of the trait it implements.
2494 /// If it implements no trait, return `None`.
2495 pub fn trait_id_of_impl(&self, def_id: DefId) -> Option<DefId> {
2496 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2499 /// If the given def ID describes a method belonging to an impl, return the
2500 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2501 pub fn impl_of_method(&self, def_id: DefId) -> Option<DefId> {
2502 if def_id.krate != LOCAL_CRATE {
2503 return match csearch::get_impl_or_trait_item(self,
2504 def_id).container() {
2505 TraitContainer(_) => None,
2506 ImplContainer(def_id) => Some(def_id),
2509 match self.impl_or_trait_items.borrow().get(&def_id).cloned() {
2510 Some(trait_item) => {
2511 match trait_item.container() {
2512 TraitContainer(_) => None,
2513 ImplContainer(def_id) => Some(def_id),
2520 /// If the given def ID describes an item belonging to a trait (either a
2521 /// default method or an implementation of a trait method), return the ID of
2522 /// the trait that the method belongs to. Otherwise, return `None`.
2523 pub fn trait_of_item(&self, def_id: DefId) -> Option<DefId> {
2524 if def_id.krate != LOCAL_CRATE {
2525 return csearch::get_trait_of_item(&self.sess.cstore, def_id, self);
2527 match self.impl_or_trait_items.borrow().get(&def_id).cloned() {
2528 Some(impl_or_trait_item) => {
2529 match impl_or_trait_item.container() {
2530 TraitContainer(def_id) => Some(def_id),
2531 ImplContainer(def_id) => self.trait_id_of_impl(def_id),
2538 /// If the given def ID describes an item belonging to a trait, (either a
2539 /// default method or an implementation of a trait method), return the ID of
2540 /// the method inside trait definition (this means that if the given def ID
2541 /// is already that of the original trait method, then the return value is
2543 /// Otherwise, return `None`.
2544 pub fn trait_item_of_item(&self, def_id: DefId) -> Option<ImplOrTraitItemId> {
2545 let impl_item = match self.impl_or_trait_items.borrow().get(&def_id) {
2546 Some(m) => m.clone(),
2547 None => return None,
2549 let name = impl_item.name();
2550 match self.trait_of_item(def_id) {
2551 Some(trait_did) => {
2552 self.trait_items(trait_did).iter()
2553 .find(|item| item.name() == name)
2554 .map(|item| item.id())
2560 /// Construct a parameter environment suitable for static contexts or other contexts where there
2561 /// are no free type/lifetime parameters in scope.
2562 pub fn empty_parameter_environment<'a>(&'a self)
2563 -> ParameterEnvironment<'a,'tcx> {
2564 ty::ParameterEnvironment { tcx: self,
2565 free_substs: Substs::empty(),
2566 caller_bounds: Vec::new(),
2567 implicit_region_bound: ty::ReEmpty,
2568 selection_cache: traits::SelectionCache::new(),
2570 // for an empty parameter
2571 // environment, there ARE no free
2572 // regions, so it shouldn't matter
2573 // what we use for the free id
2574 free_id: ast::DUMMY_NODE_ID }
2577 /// Constructs and returns a substitution that can be applied to move from
2578 /// the "outer" view of a type or method to the "inner" view.
2579 /// In general, this means converting from bound parameters to
2580 /// free parameters. Since we currently represent bound/free type
2581 /// parameters in the same way, this only has an effect on regions.
2582 pub fn construct_free_substs(&self, generics: &Generics<'tcx>,
2583 free_id: NodeId) -> Substs<'tcx> {
2585 let mut types = VecPerParamSpace::empty();
2586 for def in generics.types.as_slice() {
2587 debug!("construct_parameter_environment(): push_types_from_defs: def={:?}",
2589 types.push(def.space, self.mk_param_from_def(def));
2592 let free_id_outlive = self.region_maps.item_extent(free_id);
2594 // map bound 'a => free 'a
2595 let mut regions = VecPerParamSpace::empty();
2596 for def in generics.regions.as_slice() {
2598 ReFree(FreeRegion { scope: free_id_outlive,
2599 bound_region: BrNamed(def.def_id, def.name) });
2600 debug!("push_region_params {:?}", region);
2601 regions.push(def.space, region);
2606 regions: subst::NonerasedRegions(regions)
2610 /// See `ParameterEnvironment` struct def'n for details
2611 pub fn construct_parameter_environment<'a>(&'a self,
2613 generics: &ty::Generics<'tcx>,
2614 generic_predicates: &ty::GenericPredicates<'tcx>,
2616 -> ParameterEnvironment<'a, 'tcx>
2619 // Construct the free substs.
2622 let free_substs = self.construct_free_substs(generics, free_id);
2623 let free_id_outlive = self.region_maps.item_extent(free_id);
2626 // Compute the bounds on Self and the type parameters.
2629 let bounds = generic_predicates.instantiate(self, &free_substs);
2630 let bounds = self.liberate_late_bound_regions(free_id_outlive, &ty::Binder(bounds));
2631 let predicates = bounds.predicates.into_vec();
2633 debug!("construct_parameter_environment: free_id={:?} free_subst={:?} predicates={:?}",
2639 // Finally, we have to normalize the bounds in the environment, in
2640 // case they contain any associated type projections. This process
2641 // can yield errors if the put in illegal associated types, like
2642 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2643 // report these errors right here; this doesn't actually feel
2644 // right to me, because constructing the environment feels like a
2645 // kind of a "idempotent" action, but I'm not sure where would be
2646 // a better place. In practice, we construct environments for
2647 // every fn once during type checking, and we'll abort if there
2648 // are any errors at that point, so after type checking you can be
2649 // sure that this will succeed without errors anyway.
2652 let unnormalized_env = ty::ParameterEnvironment {
2654 free_substs: free_substs,
2655 implicit_region_bound: ty::ReScope(free_id_outlive),
2656 caller_bounds: predicates,
2657 selection_cache: traits::SelectionCache::new(),
2661 let cause = traits::ObligationCause::misc(span, free_id);
2662 traits::normalize_param_env_or_error(unnormalized_env, cause)
2665 pub fn is_method_call(&self, expr_id: NodeId) -> bool {
2666 self.tables.borrow().method_map.contains_key(&MethodCall::expr(expr_id))
2669 pub fn is_overloaded_autoderef(&self, expr_id: NodeId, autoderefs: u32) -> bool {
2670 self.tables.borrow().method_map.contains_key(&MethodCall::autoderef(expr_id,
2674 pub fn upvar_capture(&self, upvar_id: ty::UpvarId) -> Option<ty::UpvarCapture> {
2675 Some(self.tables.borrow().upvar_capture_map.get(&upvar_id).unwrap().clone())
2679 /// The category of explicit self.
2680 #[derive(Clone, Copy, Eq, PartialEq, Debug)]
2681 pub enum ExplicitSelfCategory {
2682 StaticExplicitSelfCategory,
2683 ByValueExplicitSelfCategory,
2684 ByReferenceExplicitSelfCategory(Region, hir::Mutability),
2685 ByBoxExplicitSelfCategory,
2688 /// A free variable referred to in a function.
2689 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
2690 pub struct Freevar {
2691 /// The variable being accessed free.
2694 // First span where it is accessed (there can be multiple).
2698 pub type FreevarMap = NodeMap<Vec<Freevar>>;
2700 pub type CaptureModeMap = NodeMap<hir::CaptureClause>;
2702 // Trait method resolution
2703 pub type TraitMap = NodeMap<Vec<DefId>>;
2705 // Map from the NodeId of a glob import to a list of items which are actually
2707 pub type GlobMap = HashMap<NodeId, HashSet<Name>>;
2709 impl<'tcx> ctxt<'tcx> {
2710 pub fn with_freevars<T, F>(&self, fid: NodeId, f: F) -> T where
2711 F: FnOnce(&[Freevar]) -> T,
2713 match self.freevars.borrow().get(&fid) {
2715 Some(d) => f(&d[..])
2719 pub fn make_substs_for_receiver_types(&self,
2720 trait_ref: &ty::TraitRef<'tcx>,
2721 method: &ty::Method<'tcx>)
2722 -> subst::Substs<'tcx>
2725 * Substitutes the values for the receiver's type parameters
2726 * that are found in method, leaving the method's type parameters
2730 let meth_tps: Vec<Ty> =
2731 method.generics.types.get_slice(subst::FnSpace)
2733 .map(|def| self.mk_param_from_def(def))
2735 let meth_regions: Vec<ty::Region> =
2736 method.generics.regions.get_slice(subst::FnSpace)
2738 .map(|def| def.to_early_bound_region())
2740 trait_ref.substs.clone().with_method(meth_tps, meth_regions)
2744 /// An "escaping region" is a bound region whose binder is not part of `t`.
2746 /// So, for example, consider a type like the following, which has two binders:
2748 /// for<'a> fn(x: for<'b> fn(&'a isize, &'b isize))
2749 /// ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ outer scope
2750 /// ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ inner scope
2752 /// This type has *bound regions* (`'a`, `'b`), but it does not have escaping regions, because the
2753 /// binders of both `'a` and `'b` are part of the type itself. However, if we consider the *inner
2754 /// fn type*, that type has an escaping region: `'a`.
2756 /// Note that what I'm calling an "escaping region" is often just called a "free region". However,
2757 /// we already use the term "free region". It refers to the regions that we use to represent bound
2758 /// regions on a fn definition while we are typechecking its body.
2760 /// To clarify, conceptually there is no particular difference between an "escaping" region and a
2761 /// "free" region. However, there is a big difference in practice. Basically, when "entering" a
2762 /// binding level, one is generally required to do some sort of processing to a bound region, such
2763 /// as replacing it with a fresh/skolemized region, or making an entry in the environment to
2764 /// represent the scope to which it is attached, etc. An escaping region represents a bound region
2765 /// for which this processing has not yet been done.
2766 pub trait RegionEscape {
2767 fn has_escaping_regions(&self) -> bool {
2768 self.has_regions_escaping_depth(0)
2771 fn has_regions_escaping_depth(&self, depth: u32) -> bool;
2774 pub trait HasTypeFlags {
2775 fn has_type_flags(&self, flags: TypeFlags) -> bool;
2776 fn has_projection_types(&self) -> bool {
2777 self.has_type_flags(TypeFlags::HAS_PROJECTION)
2779 fn references_error(&self) -> bool {
2780 self.has_type_flags(TypeFlags::HAS_TY_ERR)
2782 fn has_param_types(&self) -> bool {
2783 self.has_type_flags(TypeFlags::HAS_PARAMS)
2785 fn has_self_ty(&self) -> bool {
2786 self.has_type_flags(TypeFlags::HAS_SELF)
2788 fn has_infer_types(&self) -> bool {
2789 self.has_type_flags(TypeFlags::HAS_TY_INFER)
2791 fn needs_infer(&self) -> bool {
2792 self.has_type_flags(TypeFlags::HAS_TY_INFER | TypeFlags::HAS_RE_INFER)
2794 fn needs_subst(&self) -> bool {
2795 self.has_type_flags(TypeFlags::NEEDS_SUBST)
2797 fn has_closure_types(&self) -> bool {
2798 self.has_type_flags(TypeFlags::HAS_TY_CLOSURE)
2800 fn has_erasable_regions(&self) -> bool {
2801 self.has_type_flags(TypeFlags::HAS_RE_EARLY_BOUND |
2802 TypeFlags::HAS_RE_INFER |
2803 TypeFlags::HAS_FREE_REGIONS)
2805 /// Indicates whether this value references only 'global'
2806 /// types/lifetimes that are the same regardless of what fn we are
2807 /// in. This is used for caching. Errs on the side of returning
2809 fn is_global(&self) -> bool {
2810 !self.has_type_flags(TypeFlags::HAS_LOCAL_NAMES)