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;
25 use metadata::cstore::LOCAL_CRATE;
27 use middle::def::{self, ExportMap};
28 use middle::def_id::DefId;
29 use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
30 use middle::subst::{self, ParamSpace, Subst, Substs, VecPerParamSpace};
33 use middle::ty::fold::TypeFolder;
34 use middle::ty::walk::TypeWalker;
35 use util::common::memoized;
36 use util::nodemap::{NodeMap, NodeSet, DefIdMap};
37 use util::nodemap::FnvHashMap;
39 use std::borrow::{Borrow, Cow};
40 use std::cell::{Cell, RefCell};
41 use std::hash::{Hash, Hasher};
45 use std::vec::IntoIter;
46 use std::collections::{HashMap, HashSet};
47 use syntax::ast::{self, CrateNum, Name, NodeId};
48 use syntax::attr::{self, AttrMetaMethods};
49 use syntax::codemap::Span;
50 use syntax::parse::token::{InternedString, special_idents};
53 use rustc_front::hir::{ItemImpl, ItemTrait};
54 use rustc_front::hir::{MutImmutable, MutMutable, Visibility};
56 pub use self::sty::{Binder, DebruijnIndex};
57 pub use self::sty::{BuiltinBound, BuiltinBounds, ExistentialBounds};
58 pub use self::sty::{BareFnTy, FnSig, PolyFnSig, FnOutput, PolyFnOutput};
59 pub use self::sty::{ClosureTy, InferTy, ParamTy, ProjectionTy, TraitTy};
60 pub use self::sty::{ClosureSubsts, TypeAndMut};
61 pub use self::sty::{TraitRef, TypeVariants, PolyTraitRef};
62 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
63 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid, SkolemizedRegionVid};
64 pub use self::sty::BoundRegion::*;
65 pub use self::sty::FnOutput::*;
66 pub use self::sty::InferTy::*;
67 pub use self::sty::Region::*;
68 pub use self::sty::TypeVariants::*;
70 pub use self::sty::BuiltinBound::Send as BoundSend;
71 pub use self::sty::BuiltinBound::Sized as BoundSized;
72 pub use self::sty::BuiltinBound::Copy as BoundCopy;
73 pub use self::sty::BuiltinBound::Sync as BoundSync;
75 pub use self::contents::TypeContents;
76 pub use self::context::{ctxt, tls};
77 pub use self::context::{CtxtArenas, Lift, Tables};
99 pub const INITIAL_DISCRIMINANT_VALUE: Disr = 0;
103 /// The complete set of all analyses described in this module. This is
104 /// produced by the driver and fed to trans and later passes.
105 pub struct CrateAnalysis {
106 pub export_map: ExportMap,
107 pub exported_items: middle::privacy::ExportedItems,
108 pub public_items: middle::privacy::PublicItems,
109 pub reachable: NodeSet,
111 pub glob_map: Option<GlobMap>,
115 #[derive(Copy, Clone)]
122 pub fn is_present(&self) -> bool {
124 TraitDtor(..) => true,
129 pub fn has_drop_flag(&self) -> bool {
132 &TraitDtor(flag) => flag
137 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
138 pub enum ImplOrTraitItemContainer {
139 TraitContainer(DefId),
140 ImplContainer(DefId),
143 impl ImplOrTraitItemContainer {
144 pub fn id(&self) -> DefId {
146 TraitContainer(id) => id,
147 ImplContainer(id) => id,
153 pub enum ImplOrTraitItem<'tcx> {
154 ConstTraitItem(Rc<AssociatedConst<'tcx>>),
155 MethodTraitItem(Rc<Method<'tcx>>),
156 TypeTraitItem(Rc<AssociatedType<'tcx>>),
159 impl<'tcx> ImplOrTraitItem<'tcx> {
160 fn id(&self) -> ImplOrTraitItemId {
162 ConstTraitItem(ref associated_const) => {
163 ConstTraitItemId(associated_const.def_id)
165 MethodTraitItem(ref method) => MethodTraitItemId(method.def_id),
166 TypeTraitItem(ref associated_type) => {
167 TypeTraitItemId(associated_type.def_id)
172 pub fn def_id(&self) -> DefId {
174 ConstTraitItem(ref associated_const) => associated_const.def_id,
175 MethodTraitItem(ref method) => method.def_id,
176 TypeTraitItem(ref associated_type) => associated_type.def_id,
180 pub fn name(&self) -> Name {
182 ConstTraitItem(ref associated_const) => associated_const.name,
183 MethodTraitItem(ref method) => method.name,
184 TypeTraitItem(ref associated_type) => associated_type.name,
188 pub fn vis(&self) -> hir::Visibility {
190 ConstTraitItem(ref associated_const) => associated_const.vis,
191 MethodTraitItem(ref method) => method.vis,
192 TypeTraitItem(ref associated_type) => associated_type.vis,
196 pub fn container(&self) -> ImplOrTraitItemContainer {
198 ConstTraitItem(ref associated_const) => associated_const.container,
199 MethodTraitItem(ref method) => method.container,
200 TypeTraitItem(ref associated_type) => associated_type.container,
204 pub fn as_opt_method(&self) -> Option<Rc<Method<'tcx>>> {
206 MethodTraitItem(ref m) => Some((*m).clone()),
212 #[derive(Clone, Copy, Debug)]
213 pub enum ImplOrTraitItemId {
214 ConstTraitItemId(DefId),
215 MethodTraitItemId(DefId),
216 TypeTraitItemId(DefId),
219 impl ImplOrTraitItemId {
220 pub fn def_id(&self) -> DefId {
222 ConstTraitItemId(def_id) => def_id,
223 MethodTraitItemId(def_id) => def_id,
224 TypeTraitItemId(def_id) => def_id,
229 #[derive(Clone, Debug)]
230 pub struct Method<'tcx> {
232 pub generics: Generics<'tcx>,
233 pub predicates: GenericPredicates<'tcx>,
234 pub fty: BareFnTy<'tcx>,
235 pub explicit_self: ExplicitSelfCategory,
236 pub vis: hir::Visibility,
238 pub container: ImplOrTraitItemContainer,
241 impl<'tcx> Method<'tcx> {
242 pub fn new(name: Name,
243 generics: ty::Generics<'tcx>,
244 predicates: GenericPredicates<'tcx>,
246 explicit_self: ExplicitSelfCategory,
247 vis: hir::Visibility,
249 container: ImplOrTraitItemContainer)
254 predicates: predicates,
256 explicit_self: explicit_self,
259 container: container,
263 pub fn container_id(&self) -> DefId {
264 match self.container {
265 TraitContainer(id) => id,
266 ImplContainer(id) => id,
271 impl<'tcx> PartialEq for Method<'tcx> {
273 fn eq(&self, other: &Self) -> bool { self.def_id == other.def_id }
276 impl<'tcx> Eq for Method<'tcx> {}
278 impl<'tcx> Hash for Method<'tcx> {
280 fn hash<H: Hasher>(&self, s: &mut H) {
285 #[derive(Clone, Copy, Debug)]
286 pub struct AssociatedConst<'tcx> {
289 pub vis: hir::Visibility,
291 pub container: ImplOrTraitItemContainer,
295 #[derive(Clone, Copy, Debug)]
296 pub struct AssociatedType<'tcx> {
298 pub ty: Option<Ty<'tcx>>,
299 pub vis: hir::Visibility,
301 pub container: ImplOrTraitItemContainer,
304 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable)]
305 pub struct ItemVariances {
306 pub types: VecPerParamSpace<Variance>,
307 pub regions: VecPerParamSpace<Variance>,
310 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
312 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
313 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
314 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
315 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
318 #[derive(Clone, Copy, Debug)]
319 pub struct MethodCallee<'tcx> {
320 /// Impl method ID, for inherent methods, or trait method ID, otherwise.
323 pub substs: &'tcx subst::Substs<'tcx>
326 /// With method calls, we store some extra information in
327 /// side tables (i.e method_map). We use
328 /// MethodCall as a key to index into these tables instead of
329 /// just directly using the expression's NodeId. The reason
330 /// for this being that we may apply adjustments (coercions)
331 /// with the resulting expression also needing to use the
332 /// side tables. The problem with this is that we don't
333 /// assign a separate NodeId to this new expression
334 /// and so it would clash with the base expression if both
335 /// needed to add to the side tables. Thus to disambiguate
336 /// we also keep track of whether there's an adjustment in
338 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
339 pub struct MethodCall {
345 pub fn expr(id: NodeId) -> MethodCall {
352 pub fn autoderef(expr_id: NodeId, autoderef: u32) -> MethodCall {
355 autoderef: 1 + autoderef
360 // maps from an expression id that corresponds to a method call to the details
361 // of the method to be invoked
362 pub type MethodMap<'tcx> = FnvHashMap<MethodCall, MethodCallee<'tcx>>;
364 // Contains information needed to resolve types and (in the future) look up
365 // the types of AST nodes.
366 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
367 pub struct CReaderCacheKey {
373 /// A restriction that certain types must be the same size. The use of
374 /// `transmute` gives rise to these restrictions. These generally
375 /// cannot be checked until trans; therefore, each call to `transmute`
376 /// will push one or more such restriction into the
377 /// `transmute_restrictions` vector during `intrinsicck`. They are
378 /// then checked during `trans` by the fn `check_intrinsics`.
379 #[derive(Copy, Clone)]
380 pub struct TransmuteRestriction<'tcx> {
381 /// The span whence the restriction comes.
384 /// The type being transmuted from.
385 pub original_from: Ty<'tcx>,
387 /// The type being transmuted to.
388 pub original_to: Ty<'tcx>,
390 /// The type being transmuted from, with all type parameters
391 /// substituted for an arbitrary representative. Not to be shown
393 pub substituted_from: Ty<'tcx>,
395 /// The type being transmuted to, with all type parameters
396 /// substituted for an arbitrary representative. Not to be shown
398 pub substituted_to: Ty<'tcx>,
400 /// NodeId of the transmute intrinsic.
404 /// Describes the fragment-state associated with a NodeId.
406 /// Currently only unfragmented paths have entries in the table,
407 /// but longer-term this enum is expected to expand to also
408 /// include data for fragmented paths.
409 #[derive(Copy, Clone, Debug)]
410 pub enum FragmentInfo {
411 Moved { var: NodeId, move_expr: NodeId },
412 Assigned { var: NodeId, assign_expr: NodeId, assignee_id: NodeId },
415 // Flags that we track on types. These flags are propagated upwards
416 // through the type during type construction, so that we can quickly
417 // check whether the type has various kinds of types in it without
418 // recursing over the type itself.
420 flags TypeFlags: u32 {
421 const HAS_PARAMS = 1 << 0,
422 const HAS_SELF = 1 << 1,
423 const HAS_TY_INFER = 1 << 2,
424 const HAS_RE_INFER = 1 << 3,
425 const HAS_RE_EARLY_BOUND = 1 << 4,
426 const HAS_FREE_REGIONS = 1 << 5,
427 const HAS_TY_ERR = 1 << 6,
428 const HAS_PROJECTION = 1 << 7,
429 const HAS_TY_CLOSURE = 1 << 8,
431 // true if there are "names" of types and regions and so forth
432 // that are local to a particular fn
433 const HAS_LOCAL_NAMES = 1 << 9,
435 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
436 TypeFlags::HAS_SELF.bits |
437 TypeFlags::HAS_RE_EARLY_BOUND.bits,
439 // Flags representing the nominal content of a type,
440 // computed by FlagsComputation. If you add a new nominal
441 // flag, it should be added here too.
442 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
443 TypeFlags::HAS_SELF.bits |
444 TypeFlags::HAS_TY_INFER.bits |
445 TypeFlags::HAS_RE_INFER.bits |
446 TypeFlags::HAS_RE_EARLY_BOUND.bits |
447 TypeFlags::HAS_FREE_REGIONS.bits |
448 TypeFlags::HAS_TY_ERR.bits |
449 TypeFlags::HAS_PROJECTION.bits |
450 TypeFlags::HAS_TY_CLOSURE.bits |
451 TypeFlags::HAS_LOCAL_NAMES.bits,
453 // Caches for type_is_sized, type_moves_by_default
454 const SIZEDNESS_CACHED = 1 << 16,
455 const IS_SIZED = 1 << 17,
456 const MOVENESS_CACHED = 1 << 18,
457 const MOVES_BY_DEFAULT = 1 << 19,
461 pub struct TyS<'tcx> {
462 pub sty: TypeVariants<'tcx>,
463 pub flags: Cell<TypeFlags>,
465 // the maximal depth of any bound regions appearing in this type.
469 impl<'tcx> PartialEq for TyS<'tcx> {
471 fn eq(&self, other: &TyS<'tcx>) -> bool {
472 // (self as *const _) == (other as *const _)
473 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
476 impl<'tcx> Eq for TyS<'tcx> {}
478 impl<'tcx> Hash for TyS<'tcx> {
479 fn hash<H: Hasher>(&self, s: &mut H) {
480 (self as *const TyS).hash(s)
484 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
486 /// Upvars do not get their own node-id. Instead, we use the pair of
487 /// the original var id (that is, the root variable that is referenced
488 /// by the upvar) and the id of the closure expression.
489 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
492 pub closure_expr_id: NodeId,
495 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
496 pub enum BorrowKind {
497 /// Data must be immutable and is aliasable.
500 /// Data must be immutable but not aliasable. This kind of borrow
501 /// cannot currently be expressed by the user and is used only in
502 /// implicit closure bindings. It is needed when you the closure
503 /// is borrowing or mutating a mutable referent, e.g.:
505 /// let x: &mut isize = ...;
506 /// let y = || *x += 5;
508 /// If we were to try to translate this closure into a more explicit
509 /// form, we'd encounter an error with the code as written:
511 /// struct Env { x: & &mut isize }
512 /// let x: &mut isize = ...;
513 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
514 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
516 /// This is then illegal because you cannot mutate a `&mut` found
517 /// in an aliasable location. To solve, you'd have to translate with
518 /// an `&mut` borrow:
520 /// struct Env { x: & &mut isize }
521 /// let x: &mut isize = ...;
522 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
523 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
525 /// Now the assignment to `**env.x` is legal, but creating a
526 /// mutable pointer to `x` is not because `x` is not mutable. We
527 /// could fix this by declaring `x` as `let mut x`. This is ok in
528 /// user code, if awkward, but extra weird for closures, since the
529 /// borrow is hidden.
531 /// So we introduce a "unique imm" borrow -- the referent is
532 /// immutable, but not aliasable. This solves the problem. For
533 /// simplicity, we don't give users the way to express this
534 /// borrow, it's just used when translating closures.
537 /// Data is mutable and not aliasable.
541 /// Information describing the capture of an upvar. This is computed
542 /// during `typeck`, specifically by `regionck`.
543 #[derive(PartialEq, Clone, Debug, Copy)]
544 pub enum UpvarCapture {
545 /// Upvar is captured by value. This is always true when the
546 /// closure is labeled `move`, but can also be true in other cases
547 /// depending on inference.
550 /// Upvar is captured by reference.
554 #[derive(PartialEq, Clone, Copy)]
555 pub struct UpvarBorrow {
556 /// The kind of borrow: by-ref upvars have access to shared
557 /// immutable borrows, which are not part of the normal language
559 pub kind: BorrowKind,
561 /// Region of the resulting reference.
562 pub region: ty::Region,
565 pub type UpvarCaptureMap = FnvHashMap<UpvarId, UpvarCapture>;
567 #[derive(Copy, Clone)]
568 pub struct ClosureUpvar<'tcx> {
574 #[derive(Clone, Copy, PartialEq)]
575 pub enum IntVarValue {
577 UintType(ast::UintTy),
580 /// Default region to use for the bound of objects that are
581 /// supplied as the value for this type parameter. This is derived
582 /// from `T:'a` annotations appearing in the type definition. If
583 /// this is `None`, then the default is inherited from the
584 /// surrounding context. See RFC #599 for details.
585 #[derive(Copy, Clone)]
586 pub enum ObjectLifetimeDefault {
587 /// Require an explicit annotation. Occurs when multiple
588 /// `T:'a` constraints are found.
591 /// Use the base default, typically 'static, but in a fn body it is a fresh variable
594 /// Use the given region as the default.
599 pub struct TypeParameterDef<'tcx> {
602 pub space: subst::ParamSpace,
604 pub default_def_id: DefId, // for use in error reporing about defaults
605 pub default: Option<Ty<'tcx>>,
606 pub object_lifetime_default: ObjectLifetimeDefault,
610 pub struct RegionParameterDef {
613 pub space: subst::ParamSpace,
615 pub bounds: Vec<ty::Region>,
618 impl RegionParameterDef {
619 pub fn to_early_bound_region(&self) -> ty::Region {
620 ty::ReEarlyBound(ty::EarlyBoundRegion {
627 pub fn to_bound_region(&self) -> ty::BoundRegion {
628 ty::BoundRegion::BrNamed(self.def_id, self.name)
632 /// Information about the formal type/lifetime parameters associated
633 /// with an item or method. Analogous to hir::Generics.
634 #[derive(Clone, Debug)]
635 pub struct Generics<'tcx> {
636 pub types: VecPerParamSpace<TypeParameterDef<'tcx>>,
637 pub regions: VecPerParamSpace<RegionParameterDef>,
640 impl<'tcx> Generics<'tcx> {
641 pub fn empty() -> Generics<'tcx> {
643 types: VecPerParamSpace::empty(),
644 regions: VecPerParamSpace::empty(),
648 pub fn is_empty(&self) -> bool {
649 self.types.is_empty() && self.regions.is_empty()
652 pub fn has_type_params(&self, space: subst::ParamSpace) -> bool {
653 !self.types.is_empty_in(space)
656 pub fn has_region_params(&self, space: subst::ParamSpace) -> bool {
657 !self.regions.is_empty_in(space)
661 /// Bounds on generics.
663 pub struct GenericPredicates<'tcx> {
664 pub predicates: VecPerParamSpace<Predicate<'tcx>>,
667 impl<'tcx> GenericPredicates<'tcx> {
668 pub fn empty() -> GenericPredicates<'tcx> {
670 predicates: VecPerParamSpace::empty(),
674 pub fn instantiate(&self, tcx: &ctxt<'tcx>, substs: &Substs<'tcx>)
675 -> InstantiatedPredicates<'tcx> {
676 InstantiatedPredicates {
677 predicates: self.predicates.subst(tcx, substs),
681 pub fn instantiate_supertrait(&self,
683 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
684 -> InstantiatedPredicates<'tcx>
686 InstantiatedPredicates {
687 predicates: self.predicates.map(|pred| pred.subst_supertrait(tcx, poly_trait_ref))
692 #[derive(Clone, PartialEq, Eq, Hash)]
693 pub enum Predicate<'tcx> {
694 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
695 /// the `Self` type of the trait reference and `A`, `B`, and `C`
696 /// would be the parameters in the `TypeSpace`.
697 Trait(PolyTraitPredicate<'tcx>),
699 /// where `T1 == T2`.
700 Equate(PolyEquatePredicate<'tcx>),
703 RegionOutlives(PolyRegionOutlivesPredicate),
706 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
708 /// where <T as TraitRef>::Name == X, approximately.
709 /// See `ProjectionPredicate` struct for details.
710 Projection(PolyProjectionPredicate<'tcx>),
713 WellFormed(Ty<'tcx>),
715 /// trait must be object-safe
719 impl<'tcx> Predicate<'tcx> {
720 /// Performs a substitution suitable for going from a
721 /// poly-trait-ref to supertraits that must hold if that
722 /// poly-trait-ref holds. This is slightly different from a normal
723 /// substitution in terms of what happens with bound regions. See
724 /// lengthy comment below for details.
725 pub fn subst_supertrait(&self,
727 trait_ref: &ty::PolyTraitRef<'tcx>)
728 -> ty::Predicate<'tcx>
730 // The interaction between HRTB and supertraits is not entirely
731 // obvious. Let me walk you (and myself) through an example.
733 // Let's start with an easy case. Consider two traits:
735 // trait Foo<'a> : Bar<'a,'a> { }
736 // trait Bar<'b,'c> { }
738 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
739 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
740 // knew that `Foo<'x>` (for any 'x) then we also know that
741 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
742 // normal substitution.
744 // In terms of why this is sound, the idea is that whenever there
745 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
746 // holds. So if there is an impl of `T:Foo<'a>` that applies to
747 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
750 // Another example to be careful of is this:
752 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
753 // trait Bar1<'b,'c> { }
755 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
756 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
757 // reason is similar to the previous example: any impl of
758 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
759 // basically we would want to collapse the bound lifetimes from
760 // the input (`trait_ref`) and the supertraits.
762 // To achieve this in practice is fairly straightforward. Let's
763 // consider the more complicated scenario:
765 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
766 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
767 // where both `'x` and `'b` would have a DB index of 1.
768 // The substitution from the input trait-ref is therefore going to be
769 // `'a => 'x` (where `'x` has a DB index of 1).
770 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
771 // early-bound parameter and `'b' is a late-bound parameter with a
773 // - If we replace `'a` with `'x` from the input, it too will have
774 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
775 // just as we wanted.
777 // There is only one catch. If we just apply the substitution `'a
778 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
779 // adjust the DB index because we substituting into a binder (it
780 // tries to be so smart...) resulting in `for<'x> for<'b>
781 // Bar1<'x,'b>` (we have no syntax for this, so use your
782 // imagination). Basically the 'x will have DB index of 2 and 'b
783 // will have DB index of 1. Not quite what we want. So we apply
784 // the substitution to the *contents* of the trait reference,
785 // rather than the trait reference itself (put another way, the
786 // substitution code expects equal binding levels in the values
787 // from the substitution and the value being substituted into, and
788 // this trick achieves that).
790 let substs = &trait_ref.0.substs;
792 Predicate::Trait(ty::Binder(ref data)) =>
793 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
794 Predicate::Equate(ty::Binder(ref data)) =>
795 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
796 Predicate::RegionOutlives(ty::Binder(ref data)) =>
797 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
798 Predicate::TypeOutlives(ty::Binder(ref data)) =>
799 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
800 Predicate::Projection(ty::Binder(ref data)) =>
801 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
802 Predicate::WellFormed(data) =>
803 Predicate::WellFormed(data.subst(tcx, substs)),
804 Predicate::ObjectSafe(trait_def_id) =>
805 Predicate::ObjectSafe(trait_def_id),
810 #[derive(Clone, PartialEq, Eq, Hash)]
811 pub struct TraitPredicate<'tcx> {
812 pub trait_ref: TraitRef<'tcx>
814 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
816 impl<'tcx> TraitPredicate<'tcx> {
817 pub fn def_id(&self) -> DefId {
818 self.trait_ref.def_id
821 pub fn input_types(&self) -> &[Ty<'tcx>] {
822 self.trait_ref.substs.types.as_slice()
825 pub fn self_ty(&self) -> Ty<'tcx> {
826 self.trait_ref.self_ty()
830 impl<'tcx> PolyTraitPredicate<'tcx> {
831 pub fn def_id(&self) -> DefId {
836 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
837 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
838 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
840 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
841 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
842 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
843 pub type PolyRegionOutlivesPredicate = PolyOutlivesPredicate<ty::Region, ty::Region>;
844 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region>;
846 /// This kind of predicate has no *direct* correspondent in the
847 /// syntax, but it roughly corresponds to the syntactic forms:
849 /// 1. `T : TraitRef<..., Item=Type>`
850 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
852 /// In particular, form #1 is "desugared" to the combination of a
853 /// normal trait predicate (`T : TraitRef<...>`) and one of these
854 /// predicates. Form #2 is a broader form in that it also permits
855 /// equality between arbitrary types. Processing an instance of Form
856 /// #2 eventually yields one of these `ProjectionPredicate`
857 /// instances to normalize the LHS.
858 #[derive(Clone, PartialEq, Eq, Hash)]
859 pub struct ProjectionPredicate<'tcx> {
860 pub projection_ty: ProjectionTy<'tcx>,
864 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
866 impl<'tcx> PolyProjectionPredicate<'tcx> {
867 pub fn item_name(&self) -> Name {
868 self.0.projection_ty.item_name // safe to skip the binder to access a name
871 pub fn sort_key(&self) -> (DefId, Name) {
872 self.0.projection_ty.sort_key()
876 pub trait ToPolyTraitRef<'tcx> {
877 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
880 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
881 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
882 assert!(!self.has_escaping_regions());
883 ty::Binder(self.clone())
887 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
888 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
889 self.map_bound_ref(|trait_pred| trait_pred.trait_ref.clone())
893 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
894 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
895 // Note: unlike with TraitRef::to_poly_trait_ref(),
896 // self.0.trait_ref is permitted to have escaping regions.
897 // This is because here `self` has a `Binder` and so does our
898 // return value, so we are preserving the number of binding
900 ty::Binder(self.0.projection_ty.trait_ref.clone())
904 pub trait ToPredicate<'tcx> {
905 fn to_predicate(&self) -> Predicate<'tcx>;
908 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
909 fn to_predicate(&self) -> Predicate<'tcx> {
910 // we're about to add a binder, so let's check that we don't
911 // accidentally capture anything, or else that might be some
912 // weird debruijn accounting.
913 assert!(!self.has_escaping_regions());
915 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
916 trait_ref: self.clone()
921 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
922 fn to_predicate(&self) -> Predicate<'tcx> {
923 ty::Predicate::Trait(self.to_poly_trait_predicate())
927 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
928 fn to_predicate(&self) -> Predicate<'tcx> {
929 Predicate::Equate(self.clone())
933 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate {
934 fn to_predicate(&self) -> Predicate<'tcx> {
935 Predicate::RegionOutlives(self.clone())
939 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
940 fn to_predicate(&self) -> Predicate<'tcx> {
941 Predicate::TypeOutlives(self.clone())
945 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
946 fn to_predicate(&self) -> Predicate<'tcx> {
947 Predicate::Projection(self.clone())
951 impl<'tcx> Predicate<'tcx> {
952 /// Iterates over the types in this predicate. Note that in all
953 /// cases this is skipping over a binder, so late-bound regions
954 /// with depth 0 are bound by the predicate.
955 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
956 let vec: Vec<_> = match *self {
957 ty::Predicate::Trait(ref data) => {
958 data.0.trait_ref.substs.types.as_slice().to_vec()
960 ty::Predicate::Equate(ty::Binder(ref data)) => {
963 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
966 ty::Predicate::RegionOutlives(..) => {
969 ty::Predicate::Projection(ref data) => {
970 let trait_inputs = data.0.projection_ty.trait_ref.substs.types.as_slice();
973 .chain(Some(data.0.ty))
976 ty::Predicate::WellFormed(data) => {
979 ty::Predicate::ObjectSafe(_trait_def_id) => {
984 // The only reason to collect into a vector here is that I was
985 // too lazy to make the full (somewhat complicated) iterator
986 // type that would be needed here. But I wanted this fn to
987 // return an iterator conceptually, rather than a `Vec`, so as
988 // to be closer to `Ty::walk`.
992 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
994 Predicate::Trait(ref t) => {
995 Some(t.to_poly_trait_ref())
997 Predicate::Projection(..) |
998 Predicate::Equate(..) |
999 Predicate::RegionOutlives(..) |
1000 Predicate::WellFormed(..) |
1001 Predicate::ObjectSafe(..) |
1002 Predicate::TypeOutlives(..) => {
1009 /// Represents the bounds declared on a particular set of type
1010 /// parameters. Should eventually be generalized into a flag list of
1011 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1012 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1013 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1014 /// the `GenericPredicates` are expressed in terms of the bound type
1015 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1016 /// represented a set of bounds for some particular instantiation,
1017 /// meaning that the generic parameters have been substituted with
1022 /// struct Foo<T,U:Bar<T>> { ... }
1024 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1025 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1026 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1027 /// [usize:Bar<isize>]]`.
1029 pub struct InstantiatedPredicates<'tcx> {
1030 pub predicates: VecPerParamSpace<Predicate<'tcx>>,
1033 impl<'tcx> InstantiatedPredicates<'tcx> {
1034 pub fn empty() -> InstantiatedPredicates<'tcx> {
1035 InstantiatedPredicates { predicates: VecPerParamSpace::empty() }
1038 pub fn is_empty(&self) -> bool {
1039 self.predicates.is_empty()
1043 impl<'tcx> TraitRef<'tcx> {
1044 pub fn new(def_id: DefId, substs: &'tcx Substs<'tcx>) -> TraitRef<'tcx> {
1045 TraitRef { def_id: def_id, substs: substs }
1048 pub fn self_ty(&self) -> Ty<'tcx> {
1049 self.substs.self_ty().unwrap()
1052 pub fn input_types(&self) -> &[Ty<'tcx>] {
1053 // Select only the "input types" from a trait-reference. For
1054 // now this is all the types that appear in the
1055 // trait-reference, but it should eventually exclude
1056 // associated types.
1057 self.substs.types.as_slice()
1061 /// When type checking, we use the `ParameterEnvironment` to track
1062 /// details about the type/lifetime parameters that are in scope.
1063 /// It primarily stores the bounds information.
1065 /// Note: This information might seem to be redundant with the data in
1066 /// `tcx.ty_param_defs`, but it is not. That table contains the
1067 /// parameter definitions from an "outside" perspective, but this
1068 /// struct will contain the bounds for a parameter as seen from inside
1069 /// the function body. Currently the only real distinction is that
1070 /// bound lifetime parameters are replaced with free ones, but in the
1071 /// future I hope to refine the representation of types so as to make
1072 /// more distinctions clearer.
1074 pub struct ParameterEnvironment<'a, 'tcx:'a> {
1075 pub tcx: &'a ctxt<'tcx>,
1077 /// See `construct_free_substs` for details.
1078 pub free_substs: Substs<'tcx>,
1080 /// Each type parameter has an implicit region bound that
1081 /// indicates it must outlive at least the function body (the user
1082 /// may specify stronger requirements). This field indicates the
1083 /// region of the callee.
1084 pub implicit_region_bound: ty::Region,
1086 /// Obligations that the caller must satisfy. This is basically
1087 /// the set of bounds on the in-scope type parameters, translated
1088 /// into Obligations, and elaborated and normalized.
1089 pub caller_bounds: Vec<ty::Predicate<'tcx>>,
1091 /// Caches the results of trait selection. This cache is used
1092 /// for things that have to do with the parameters in scope.
1093 pub selection_cache: traits::SelectionCache<'tcx>,
1095 /// Scope that is attached to free regions for this scope. This
1096 /// is usually the id of the fn body, but for more abstract scopes
1097 /// like structs we often use the node-id of the struct.
1099 /// FIXME(#3696). It would be nice to refactor so that free
1100 /// regions don't have this implicit scope and instead introduce
1101 /// relationships in the environment.
1102 pub free_id: ast::NodeId,
1105 impl<'a, 'tcx> ParameterEnvironment<'a, 'tcx> {
1106 pub fn with_caller_bounds(&self,
1107 caller_bounds: Vec<ty::Predicate<'tcx>>)
1108 -> ParameterEnvironment<'a,'tcx>
1110 ParameterEnvironment {
1112 free_substs: self.free_substs.clone(),
1113 implicit_region_bound: self.implicit_region_bound,
1114 caller_bounds: caller_bounds,
1115 selection_cache: traits::SelectionCache::new(),
1116 free_id: self.free_id,
1120 pub fn for_item(cx: &'a ctxt<'tcx>, id: NodeId) -> ParameterEnvironment<'a, 'tcx> {
1121 match cx.map.find(id) {
1122 Some(ast_map::NodeImplItem(ref impl_item)) => {
1123 match impl_item.node {
1124 hir::TypeImplItem(_) => {
1125 // associated types don't have their own entry (for some reason),
1126 // so for now just grab environment for the impl
1127 let impl_id = cx.map.get_parent(id);
1128 let impl_def_id = cx.map.local_def_id(impl_id);
1129 let scheme = cx.lookup_item_type(impl_def_id);
1130 let predicates = cx.lookup_predicates(impl_def_id);
1131 cx.construct_parameter_environment(impl_item.span,
1136 hir::ConstImplItem(_, _) => {
1137 let def_id = cx.map.local_def_id(id);
1138 let scheme = cx.lookup_item_type(def_id);
1139 let predicates = cx.lookup_predicates(def_id);
1140 cx.construct_parameter_environment(impl_item.span,
1145 hir::MethodImplItem(_, ref body) => {
1146 let method_def_id = cx.map.local_def_id(id);
1147 match cx.impl_or_trait_item(method_def_id) {
1148 MethodTraitItem(ref method_ty) => {
1149 let method_generics = &method_ty.generics;
1150 let method_bounds = &method_ty.predicates;
1151 cx.construct_parameter_environment(
1159 .bug("ParameterEnvironment::for_item(): \
1160 got non-method item from impl method?!")
1166 Some(ast_map::NodeTraitItem(trait_item)) => {
1167 match trait_item.node {
1168 hir::TypeTraitItem(..) => {
1169 // associated types don't have their own entry (for some reason),
1170 // so for now just grab environment for the trait
1171 let trait_id = cx.map.get_parent(id);
1172 let trait_def_id = cx.map.local_def_id(trait_id);
1173 let trait_def = cx.lookup_trait_def(trait_def_id);
1174 let predicates = cx.lookup_predicates(trait_def_id);
1175 cx.construct_parameter_environment(trait_item.span,
1176 &trait_def.generics,
1180 hir::ConstTraitItem(..) => {
1181 let def_id = cx.map.local_def_id(id);
1182 let scheme = cx.lookup_item_type(def_id);
1183 let predicates = cx.lookup_predicates(def_id);
1184 cx.construct_parameter_environment(trait_item.span,
1189 hir::MethodTraitItem(_, ref body) => {
1190 // for the body-id, use the id of the body
1191 // block, unless this is a trait method with
1192 // no default, then fallback to the method id.
1193 let body_id = body.as_ref().map(|b| b.id).unwrap_or(id);
1194 let method_def_id = cx.map.local_def_id(id);
1195 match cx.impl_or_trait_item(method_def_id) {
1196 MethodTraitItem(ref method_ty) => {
1197 let method_generics = &method_ty.generics;
1198 let method_bounds = &method_ty.predicates;
1199 cx.construct_parameter_environment(
1207 .bug("ParameterEnvironment::for_item(): \
1208 got non-method item from provided \
1215 Some(ast_map::NodeItem(item)) => {
1217 hir::ItemFn(_, _, _, _, _, ref body) => {
1218 // We assume this is a function.
1219 let fn_def_id = cx.map.local_def_id(id);
1220 let fn_scheme = cx.lookup_item_type(fn_def_id);
1221 let fn_predicates = cx.lookup_predicates(fn_def_id);
1223 cx.construct_parameter_environment(item.span,
1224 &fn_scheme.generics,
1229 hir::ItemStruct(..) |
1231 hir::ItemConst(..) |
1232 hir::ItemStatic(..) => {
1233 let def_id = cx.map.local_def_id(id);
1234 let scheme = cx.lookup_item_type(def_id);
1235 let predicates = cx.lookup_predicates(def_id);
1236 cx.construct_parameter_environment(item.span,
1241 hir::ItemTrait(..) => {
1242 let def_id = cx.map.local_def_id(id);
1243 let trait_def = cx.lookup_trait_def(def_id);
1244 let predicates = cx.lookup_predicates(def_id);
1245 cx.construct_parameter_environment(item.span,
1246 &trait_def.generics,
1251 cx.sess.span_bug(item.span,
1252 "ParameterEnvironment::from_item():
1253 can't create a parameter \
1254 environment for this kind of item")
1258 Some(ast_map::NodeExpr(..)) => {
1259 // This is a convenience to allow closures to work.
1260 ParameterEnvironment::for_item(cx, cx.map.get_parent(id))
1263 cx.sess.bug(&format!("ParameterEnvironment::from_item(): \
1264 `{}` is not an item",
1265 cx.map.node_to_string(id)))
1271 /// A "type scheme", in ML terminology, is a type combined with some
1272 /// set of generic types that the type is, well, generic over. In Rust
1273 /// terms, it is the "type" of a fn item or struct -- this type will
1274 /// include various generic parameters that must be substituted when
1275 /// the item/struct is referenced. That is called converting the type
1276 /// scheme to a monotype.
1278 /// - `generics`: the set of type parameters and their bounds
1279 /// - `ty`: the base types, which may reference the parameters defined
1282 /// Note that TypeSchemes are also sometimes called "polytypes" (and
1283 /// in fact this struct used to carry that name, so you may find some
1284 /// stray references in a comment or something). We try to reserve the
1285 /// "poly" prefix to refer to higher-ranked things, as in
1288 /// Note that each item also comes with predicates, see
1289 /// `lookup_predicates`.
1290 #[derive(Clone, Debug)]
1291 pub struct TypeScheme<'tcx> {
1292 pub generics: Generics<'tcx>,
1297 flags TraitFlags: u32 {
1298 const NO_TRAIT_FLAGS = 0,
1299 const HAS_DEFAULT_IMPL = 1 << 0,
1300 const IS_OBJECT_SAFE = 1 << 1,
1301 const OBJECT_SAFETY_VALID = 1 << 2,
1302 const IMPLS_VALID = 1 << 3,
1306 /// As `TypeScheme` but for a trait ref.
1307 pub struct TraitDef<'tcx> {
1308 pub unsafety: hir::Unsafety,
1310 /// If `true`, then this trait had the `#[rustc_paren_sugar]`
1311 /// attribute, indicating that it should be used with `Foo()`
1312 /// sugar. This is a temporary thing -- eventually any trait wil
1313 /// be usable with the sugar (or without it).
1314 pub paren_sugar: bool,
1316 /// Generic type definitions. Note that `Self` is listed in here
1317 /// as having a single bound, the trait itself (e.g., in the trait
1318 /// `Eq`, there is a single bound `Self : Eq`). This is so that
1319 /// default methods get to assume that the `Self` parameters
1320 /// implements the trait.
1321 pub generics: Generics<'tcx>,
1323 pub trait_ref: TraitRef<'tcx>,
1325 /// A list of the associated types defined in this trait. Useful
1326 /// for resolving `X::Foo` type markers.
1327 pub associated_type_names: Vec<Name>,
1329 // Impls of this trait. To allow for quicker lookup, the impls are indexed
1330 // by a simplified version of their Self type: impls with a simplifiable
1331 // Self are stored in nonblanket_impls keyed by it, while all other impls
1332 // are stored in blanket_impls.
1334 /// Impls of the trait.
1335 pub nonblanket_impls: RefCell<
1336 FnvHashMap<fast_reject::SimplifiedType, Vec<DefId>>
1339 /// Blanket impls associated with the trait.
1340 pub blanket_impls: RefCell<Vec<DefId>>,
1343 pub flags: Cell<TraitFlags>
1346 impl<'tcx> TraitDef<'tcx> {
1347 // returns None if not yet calculated
1348 pub fn object_safety(&self) -> Option<bool> {
1349 if self.flags.get().intersects(TraitFlags::OBJECT_SAFETY_VALID) {
1350 Some(self.flags.get().intersects(TraitFlags::IS_OBJECT_SAFE))
1356 pub fn set_object_safety(&self, is_safe: bool) {
1357 assert!(self.object_safety().map(|cs| cs == is_safe).unwrap_or(true));
1359 self.flags.get() | if is_safe {
1360 TraitFlags::OBJECT_SAFETY_VALID | TraitFlags::IS_OBJECT_SAFE
1362 TraitFlags::OBJECT_SAFETY_VALID
1367 /// Records a trait-to-implementation mapping.
1368 pub fn record_impl(&self,
1371 impl_trait_ref: TraitRef<'tcx>) {
1372 debug!("TraitDef::record_impl for {:?}, from {:?}",
1373 self, impl_trait_ref);
1375 // We don't want to borrow_mut after we already populated all impls,
1376 // so check if an impl is present with an immutable borrow first.
1377 if let Some(sty) = fast_reject::simplify_type(tcx,
1378 impl_trait_ref.self_ty(), false) {
1379 if let Some(is) = self.nonblanket_impls.borrow().get(&sty) {
1380 if is.contains(&impl_def_id) {
1381 return // duplicate - skip
1385 self.nonblanket_impls.borrow_mut().entry(sty).or_insert(vec![]).push(impl_def_id)
1387 if self.blanket_impls.borrow().contains(&impl_def_id) {
1388 return // duplicate - skip
1390 self.blanket_impls.borrow_mut().push(impl_def_id)
1395 pub fn for_each_impl<F: FnMut(DefId)>(&self, tcx: &ctxt<'tcx>, mut f: F) {
1396 tcx.populate_implementations_for_trait_if_necessary(self.trait_ref.def_id);
1398 for &impl_def_id in self.blanket_impls.borrow().iter() {
1402 for v in self.nonblanket_impls.borrow().values() {
1403 for &impl_def_id in v {
1409 /// Iterate over every impl that could possibly match the
1410 /// self-type `self_ty`.
1411 pub fn for_each_relevant_impl<F: FnMut(DefId)>(&self,
1416 tcx.populate_implementations_for_trait_if_necessary(self.trait_ref.def_id);
1418 for &impl_def_id in self.blanket_impls.borrow().iter() {
1422 // simplify_type(.., false) basically replaces type parameters and
1423 // projections with infer-variables. This is, of course, done on
1424 // the impl trait-ref when it is instantiated, but not on the
1425 // predicate trait-ref which is passed here.
1427 // for example, if we match `S: Copy` against an impl like
1428 // `impl<T:Copy> Copy for Option<T>`, we replace the type variable
1429 // in `Option<T>` with an infer variable, to `Option<_>` (this
1430 // doesn't actually change fast_reject output), but we don't
1431 // replace `S` with anything - this impl of course can't be
1432 // selected, and as there are hundreds of similar impls,
1433 // considering them would significantly harm performance.
1434 if let Some(simp) = fast_reject::simplify_type(tcx, self_ty, true) {
1435 if let Some(impls) = self.nonblanket_impls.borrow().get(&simp) {
1436 for &impl_def_id in impls {
1441 for v in self.nonblanket_impls.borrow().values() {
1442 for &impl_def_id in v {
1452 flags AdtFlags: u32 {
1453 const NO_ADT_FLAGS = 0,
1454 const IS_ENUM = 1 << 0,
1455 const IS_DTORCK = 1 << 1, // is this a dtorck type?
1456 const IS_DTORCK_VALID = 1 << 2,
1457 const IS_PHANTOM_DATA = 1 << 3,
1458 const IS_SIMD = 1 << 4,
1459 const IS_FUNDAMENTAL = 1 << 5,
1460 const IS_NO_DROP_FLAG = 1 << 6,
1464 pub type AdtDef<'tcx> = &'tcx AdtDefData<'tcx, 'static>;
1465 pub type VariantDef<'tcx> = &'tcx VariantDefData<'tcx, 'static>;
1466 pub type FieldDef<'tcx> = &'tcx FieldDefData<'tcx, 'static>;
1468 // See comment on AdtDefData for explanation
1469 pub type AdtDefMaster<'tcx> = &'tcx AdtDefData<'tcx, 'tcx>;
1470 pub type VariantDefMaster<'tcx> = &'tcx VariantDefData<'tcx, 'tcx>;
1471 pub type FieldDefMaster<'tcx> = &'tcx FieldDefData<'tcx, 'tcx>;
1473 pub struct VariantDefData<'tcx, 'container: 'tcx> {
1475 pub name: Name, // struct's name if this is a struct
1477 pub fields: Vec<FieldDefData<'tcx, 'container>>
1480 pub struct FieldDefData<'tcx, 'container: 'tcx> {
1481 /// The field's DefId. NOTE: the fields of tuple-like enum variants
1482 /// are not real items, and don't have entries in tcache etc.
1484 /// special_idents::unnamed_field.name
1485 /// if this is a tuple-like field
1487 pub vis: hir::Visibility,
1488 /// TyIVar is used here to allow for variance (see the doc at
1490 ty: ivar::TyIVar<'tcx, 'container>
1493 /// The definition of an abstract data type - a struct or enum.
1495 /// These are all interned (by intern_adt_def) into the adt_defs
1498 /// Because of the possibility of nested tcx-s, this type
1499 /// needs 2 lifetimes: the traditional variant lifetime ('tcx)
1500 /// bounding the lifetime of the inner types is of course necessary.
1501 /// However, it is not sufficient - types from a child tcx must
1502 /// not be leaked into the master tcx by being stored in an AdtDefData.
1504 /// The 'container lifetime ensures that by outliving the container
1505 /// tcx and preventing shorter-lived types from being inserted. When
1506 /// write access is not needed, the 'container lifetime can be
1507 /// erased to 'static, which can be done by the AdtDef wrapper.
1508 pub struct AdtDefData<'tcx, 'container: 'tcx> {
1510 pub variants: Vec<VariantDefData<'tcx, 'container>>,
1511 destructor: Cell<Option<DefId>>,
1512 flags: Cell<AdtFlags>,
1515 impl<'tcx, 'container> PartialEq for AdtDefData<'tcx, 'container> {
1516 // AdtDefData are always interned and this is part of TyS equality
1518 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1521 impl<'tcx, 'container> Eq for AdtDefData<'tcx, 'container> {}
1523 impl<'tcx, 'container> Hash for AdtDefData<'tcx, 'container> {
1525 fn hash<H: Hasher>(&self, s: &mut H) {
1526 (self as *const AdtDefData).hash(s)
1531 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1532 pub enum AdtKind { Struct, Enum }
1534 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1535 pub enum VariantKind { Dict, Tuple, Unit }
1537 impl<'tcx, 'container> AdtDefData<'tcx, 'container> {
1538 fn new(tcx: &ctxt<'tcx>,
1541 variants: Vec<VariantDefData<'tcx, 'container>>) -> Self {
1542 let mut flags = AdtFlags::NO_ADT_FLAGS;
1543 let attrs = tcx.get_attrs(did);
1544 if attr::contains_name(&attrs, "fundamental") {
1545 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1547 if attr::contains_name(&attrs, "unsafe_no_drop_flag") {
1548 flags = flags | AdtFlags::IS_NO_DROP_FLAG;
1550 if tcx.lookup_simd(did) {
1551 flags = flags | AdtFlags::IS_SIMD;
1553 if Some(did) == tcx.lang_items.phantom_data() {
1554 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1556 if let AdtKind::Enum = kind {
1557 flags = flags | AdtFlags::IS_ENUM;
1562 flags: Cell::new(flags),
1563 destructor: Cell::new(None)
1567 fn calculate_dtorck(&'tcx self, tcx: &ctxt<'tcx>) {
1568 if tcx.is_adt_dtorck(self) {
1569 self.flags.set(self.flags.get() | AdtFlags::IS_DTORCK);
1571 self.flags.set(self.flags.get() | AdtFlags::IS_DTORCK_VALID)
1574 /// Returns the kind of the ADT - Struct or Enum.
1576 pub fn adt_kind(&self) -> AdtKind {
1577 if self.flags.get().intersects(AdtFlags::IS_ENUM) {
1584 /// Returns whether this is a dtorck type. If this returns
1585 /// true, this type being safe for destruction requires it to be
1586 /// alive; Otherwise, only the contents are required to be.
1588 pub fn is_dtorck(&'tcx self, tcx: &ctxt<'tcx>) -> bool {
1589 if !self.flags.get().intersects(AdtFlags::IS_DTORCK_VALID) {
1590 self.calculate_dtorck(tcx)
1592 self.flags.get().intersects(AdtFlags::IS_DTORCK)
1595 /// Returns whether this type is #[fundamental] for the purposes
1596 /// of coherence checking.
1598 pub fn is_fundamental(&self) -> bool {
1599 self.flags.get().intersects(AdtFlags::IS_FUNDAMENTAL)
1603 pub fn is_simd(&self) -> bool {
1604 self.flags.get().intersects(AdtFlags::IS_SIMD)
1607 /// Returns true if this is PhantomData<T>.
1609 pub fn is_phantom_data(&self) -> bool {
1610 self.flags.get().intersects(AdtFlags::IS_PHANTOM_DATA)
1613 /// Returns whether this type has a destructor.
1614 pub fn has_dtor(&self) -> bool {
1615 match self.dtor_kind() {
1617 TraitDtor(..) => true
1621 /// Asserts this is a struct and returns the struct's unique
1623 pub fn struct_variant(&self) -> &VariantDefData<'tcx, 'container> {
1624 assert!(self.adt_kind() == AdtKind::Struct);
1629 pub fn type_scheme(&self, tcx: &ctxt<'tcx>) -> TypeScheme<'tcx> {
1630 tcx.lookup_item_type(self.did)
1634 pub fn predicates(&self, tcx: &ctxt<'tcx>) -> GenericPredicates<'tcx> {
1635 tcx.lookup_predicates(self.did)
1638 /// Returns an iterator over all fields contained
1641 pub fn all_fields(&self) ->
1643 slice::Iter<VariantDefData<'tcx, 'container>>,
1644 slice::Iter<FieldDefData<'tcx, 'container>>,
1645 for<'s> fn(&'s VariantDefData<'tcx, 'container>)
1646 -> slice::Iter<'s, FieldDefData<'tcx, 'container>>
1648 self.variants.iter().flat_map(VariantDefData::fields_iter)
1652 pub fn is_empty(&self) -> bool {
1653 self.variants.is_empty()
1657 pub fn is_univariant(&self) -> bool {
1658 self.variants.len() == 1
1661 pub fn is_payloadfree(&self) -> bool {
1662 !self.variants.is_empty() &&
1663 self.variants.iter().all(|v| v.fields.is_empty())
1666 pub fn variant_with_id(&self, vid: DefId) -> &VariantDefData<'tcx, 'container> {
1669 .find(|v| v.did == vid)
1670 .expect("variant_with_id: unknown variant")
1673 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1676 .position(|v| v.did == vid)
1677 .expect("variant_index_with_id: unknown variant")
1680 pub fn variant_of_def(&self, def: def::Def) -> &VariantDefData<'tcx, 'container> {
1682 def::DefVariant(_, vid, _) => self.variant_with_id(vid),
1683 def::DefStruct(..) | def::DefTy(..) => self.struct_variant(),
1684 _ => panic!("unexpected def {:?} in variant_of_def", def)
1688 pub fn destructor(&self) -> Option<DefId> {
1689 self.destructor.get()
1692 pub fn set_destructor(&self, dtor: DefId) {
1693 self.destructor.set(Some(dtor));
1696 pub fn dtor_kind(&self) -> DtorKind {
1697 match self.destructor.get() {
1699 TraitDtor(!self.flags.get().intersects(AdtFlags::IS_NO_DROP_FLAG))
1706 impl<'tcx, 'container> VariantDefData<'tcx, 'container> {
1708 fn fields_iter(&self) -> slice::Iter<FieldDefData<'tcx, 'container>> {
1712 pub fn kind(&self) -> VariantKind {
1713 match self.fields.get(0) {
1714 None => VariantKind::Unit,
1715 Some(&FieldDefData { name, .. }) if name == special_idents::unnamed_field.name => {
1718 Some(_) => VariantKind::Dict
1722 pub fn is_tuple_struct(&self) -> bool {
1723 self.kind() == VariantKind::Tuple
1727 pub fn find_field_named(&self,
1729 -> Option<&FieldDefData<'tcx, 'container>> {
1730 self.fields.iter().find(|f| f.name == name)
1734 pub fn field_named(&self, name: ast::Name) -> &FieldDefData<'tcx, 'container> {
1735 self.find_field_named(name).unwrap()
1739 impl<'tcx, 'container> FieldDefData<'tcx, 'container> {
1740 pub fn new(did: DefId,
1742 vis: hir::Visibility) -> Self {
1747 ty: ivar::TyIVar::new()
1751 pub fn ty(&self, tcx: &ctxt<'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1752 self.unsubst_ty().subst(tcx, subst)
1755 pub fn unsubst_ty(&self) -> Ty<'tcx> {
1759 pub fn fulfill_ty(&self, ty: Ty<'container>) {
1760 self.ty.fulfill(ty);
1764 /// Records the substitutions used to translate the polytype for an
1765 /// item into the monotype of an item reference.
1767 pub struct ItemSubsts<'tcx> {
1768 pub substs: Substs<'tcx>,
1771 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Debug, RustcEncodable, RustcDecodable)]
1772 pub enum ClosureKind {
1773 // Warning: Ordering is significant here! The ordering is chosen
1774 // because the trait Fn is a subtrait of FnMut and so in turn, and
1775 // hence we order it so that Fn < FnMut < FnOnce.
1782 pub fn trait_did(&self, cx: &ctxt) -> DefId {
1783 let result = match *self {
1784 FnClosureKind => cx.lang_items.require(FnTraitLangItem),
1785 FnMutClosureKind => {
1786 cx.lang_items.require(FnMutTraitLangItem)
1788 FnOnceClosureKind => {
1789 cx.lang_items.require(FnOnceTraitLangItem)
1793 Ok(trait_did) => trait_did,
1794 Err(err) => cx.sess.fatal(&err[..]),
1798 /// True if this a type that impls this closure kind
1799 /// must also implement `other`.
1800 pub fn extends(self, other: ty::ClosureKind) -> bool {
1801 match (self, other) {
1802 (FnClosureKind, FnClosureKind) => true,
1803 (FnClosureKind, FnMutClosureKind) => true,
1804 (FnClosureKind, FnOnceClosureKind) => true,
1805 (FnMutClosureKind, FnMutClosureKind) => true,
1806 (FnMutClosureKind, FnOnceClosureKind) => true,
1807 (FnOnceClosureKind, FnOnceClosureKind) => true,
1813 impl<'tcx> TyS<'tcx> {
1814 /// Iterator that walks `self` and any types reachable from
1815 /// `self`, in depth-first order. Note that just walks the types
1816 /// that appear in `self`, it does not descend into the fields of
1817 /// structs or variants. For example:
1820 /// isize => { isize }
1821 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
1822 /// [isize] => { [isize], isize }
1824 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
1825 TypeWalker::new(self)
1828 /// Iterator that walks the immediate children of `self`. Hence
1829 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
1830 /// (but not `i32`, like `walk`).
1831 pub fn walk_shallow(&'tcx self) -> IntoIter<Ty<'tcx>> {
1832 walk::walk_shallow(self)
1835 /// Walks `ty` and any types appearing within `ty`, invoking the
1836 /// callback `f` on each type. If the callback returns false, then the
1837 /// children of the current type are ignored.
1839 /// Note: prefer `ty.walk()` where possible.
1840 pub fn maybe_walk<F>(&'tcx self, mut f: F)
1841 where F : FnMut(Ty<'tcx>) -> bool
1843 let mut walker = self.walk();
1844 while let Some(ty) = walker.next() {
1846 walker.skip_current_subtree();
1852 impl<'tcx> ItemSubsts<'tcx> {
1853 pub fn empty() -> ItemSubsts<'tcx> {
1854 ItemSubsts { substs: Substs::empty() }
1857 pub fn is_noop(&self) -> bool {
1858 self.substs.is_noop()
1862 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1863 pub enum LvaluePreference {
1868 impl LvaluePreference {
1869 pub fn from_mutbl(m: hir::Mutability) -> Self {
1871 hir::MutMutable => PreferMutLvalue,
1872 hir::MutImmutable => NoPreference,
1877 /// Helper for looking things up in the various maps that are populated during
1878 /// typeck::collect (e.g., `cx.impl_or_trait_items`, `cx.tcache`, etc). All of
1879 /// these share the pattern that if the id is local, it should have been loaded
1880 /// into the map by the `typeck::collect` phase. If the def-id is external,
1881 /// then we have to go consult the crate loading code (and cache the result for
1883 fn lookup_locally_or_in_crate_store<V, F>(descr: &str,
1885 map: &RefCell<DefIdMap<V>>,
1886 load_external: F) -> V where
1890 match map.borrow().get(&def_id).cloned() {
1891 Some(v) => { return v; }
1895 if def_id.is_local() {
1896 panic!("No def'n found for {:?} in tcx.{}", def_id, descr);
1898 let v = load_external();
1899 map.borrow_mut().insert(def_id, v.clone());
1904 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
1906 hir::MutMutable => MutBorrow,
1907 hir::MutImmutable => ImmBorrow,
1911 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
1912 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
1913 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
1915 pub fn to_mutbl_lossy(self) -> hir::Mutability {
1917 MutBorrow => hir::MutMutable,
1918 ImmBorrow => hir::MutImmutable,
1920 // We have no type corresponding to a unique imm borrow, so
1921 // use `&mut`. It gives all the capabilities of an `&uniq`
1922 // and hence is a safe "over approximation".
1923 UniqueImmBorrow => hir::MutMutable,
1927 pub fn to_user_str(&self) -> &'static str {
1929 MutBorrow => "mutable",
1930 ImmBorrow => "immutable",
1931 UniqueImmBorrow => "uniquely immutable",
1936 impl<'tcx> ctxt<'tcx> {
1937 pub fn node_id_to_type(&self, id: NodeId) -> Ty<'tcx> {
1938 match self.node_id_to_type_opt(id) {
1940 None => self.sess.bug(
1941 &format!("node_id_to_type: no type for node `{}`",
1942 self.map.node_to_string(id)))
1946 pub fn node_id_to_type_opt(&self, id: NodeId) -> Option<Ty<'tcx>> {
1947 self.tables.borrow().node_types.get(&id).cloned()
1950 pub fn node_id_item_substs(&self, id: NodeId) -> ItemSubsts<'tcx> {
1951 match self.tables.borrow().item_substs.get(&id) {
1952 None => ItemSubsts::empty(),
1953 Some(ts) => ts.clone(),
1957 // Returns the type of a pattern as a monotype. Like @expr_ty, this function
1958 // doesn't provide type parameter substitutions.
1959 pub fn pat_ty(&self, pat: &hir::Pat) -> Ty<'tcx> {
1960 self.node_id_to_type(pat.id)
1962 pub fn pat_ty_opt(&self, pat: &hir::Pat) -> Option<Ty<'tcx>> {
1963 self.node_id_to_type_opt(pat.id)
1966 // Returns the type of an expression as a monotype.
1968 // NB (1): This is the PRE-ADJUSTMENT TYPE for the expression. That is, in
1969 // some cases, we insert `AutoAdjustment` annotations such as auto-deref or
1970 // auto-ref. The type returned by this function does not consider such
1971 // adjustments. See `expr_ty_adjusted()` instead.
1973 // NB (2): This type doesn't provide type parameter substitutions; e.g. if you
1974 // ask for the type of "id" in "id(3)", it will return "fn(&isize) -> isize"
1975 // instead of "fn(ty) -> T with T = isize".
1976 pub fn expr_ty(&self, expr: &hir::Expr) -> Ty<'tcx> {
1977 self.node_id_to_type(expr.id)
1980 pub fn expr_ty_opt(&self, expr: &hir::Expr) -> Option<Ty<'tcx>> {
1981 self.node_id_to_type_opt(expr.id)
1984 /// Returns the type of `expr`, considering any `AutoAdjustment`
1985 /// entry recorded for that expression.
1987 /// It would almost certainly be better to store the adjusted ty in with
1988 /// the `AutoAdjustment`, but I opted not to do this because it would
1989 /// require serializing and deserializing the type and, although that's not
1990 /// hard to do, I just hate that code so much I didn't want to touch it
1991 /// unless it was to fix it properly, which seemed a distraction from the
1992 /// thread at hand! -nmatsakis
1993 pub fn expr_ty_adjusted(&self, expr: &hir::Expr) -> Ty<'tcx> {
1995 .adjust(self, expr.span, expr.id,
1996 self.tables.borrow().adjustments.get(&expr.id),
1998 self.tables.borrow().method_map.get(&method_call).map(|method| method.ty)
2002 pub fn expr_span(&self, id: NodeId) -> Span {
2003 match self.map.find(id) {
2004 Some(ast_map::NodeExpr(e)) => {
2008 self.sess.bug(&format!("Node id {} is not an expr: {:?}",
2012 self.sess.bug(&format!("Node id {} is not present \
2013 in the node map", id));
2018 pub fn local_var_name_str(&self, id: NodeId) -> InternedString {
2019 match self.map.find(id) {
2020 Some(ast_map::NodeLocal(pat)) => {
2022 hir::PatIdent(_, ref path1, _) => path1.node.name.as_str(),
2024 self.sess.bug(&format!("Variable id {} maps to {:?}, not local", id, pat));
2028 r => self.sess.bug(&format!("Variable id {} maps to {:?}, not local", id, r)),
2032 pub fn resolve_expr(&self, expr: &hir::Expr) -> def::Def {
2033 match self.def_map.borrow().get(&expr.id) {
2034 Some(def) => def.full_def(),
2036 self.sess.span_bug(expr.span, &format!(
2037 "no def-map entry for expr {}", expr.id));
2042 pub fn expr_is_lval(&self, expr: &hir::Expr) -> bool {
2044 hir::ExprPath(..) => {
2045 // We can't use resolve_expr here, as this needs to run on broken
2046 // programs. We don't need to through - associated items are all
2048 match self.def_map.borrow().get(&expr.id) {
2049 Some(&def::PathResolution {
2050 base_def: def::DefStatic(..), ..
2051 }) | Some(&def::PathResolution {
2052 base_def: def::DefUpvar(..), ..
2053 }) | Some(&def::PathResolution {
2054 base_def: def::DefLocal(..), ..
2061 None => self.sess.span_bug(expr.span, &format!(
2062 "no def for path {}", expr.id))
2066 hir::ExprUnary(hir::UnDeref, _) |
2067 hir::ExprField(..) |
2068 hir::ExprTupField(..) |
2069 hir::ExprIndex(..) => {
2074 hir::ExprMethodCall(..) |
2075 hir::ExprStruct(..) |
2076 hir::ExprRange(..) |
2079 hir::ExprMatch(..) |
2080 hir::ExprClosure(..) |
2081 hir::ExprBlock(..) |
2082 hir::ExprRepeat(..) |
2084 hir::ExprBreak(..) |
2085 hir::ExprAgain(..) |
2087 hir::ExprWhile(..) |
2089 hir::ExprAssign(..) |
2090 hir::ExprInlineAsm(..) |
2091 hir::ExprAssignOp(..) |
2093 hir::ExprUnary(..) |
2095 hir::ExprAddrOf(..) |
2096 hir::ExprBinary(..) |
2097 hir::ExprCast(..) => {
2103 pub fn provided_trait_methods(&self, id: DefId) -> Vec<Rc<Method<'tcx>>> {
2104 if let Some(id) = self.map.as_local_node_id(id) {
2105 if let ItemTrait(_, _, _, ref ms) = self.map.expect_item(id).node {
2106 ms.iter().filter_map(|ti| {
2107 if let hir::MethodTraitItem(_, Some(_)) = ti.node {
2108 match self.impl_or_trait_item(self.map.local_def_id(ti.id)) {
2109 MethodTraitItem(m) => Some(m),
2111 self.sess.bug("provided_trait_methods(): \
2112 non-method item found from \
2113 looking up provided method?!")
2121 self.sess.bug(&format!("provided_trait_methods: `{:?}` is not a trait", id))
2124 csearch::get_provided_trait_methods(self, id)
2128 pub fn associated_consts(&self, id: DefId) -> Vec<Rc<AssociatedConst<'tcx>>> {
2129 if let Some(id) = self.map.as_local_node_id(id) {
2130 match self.map.expect_item(id).node {
2131 ItemTrait(_, _, _, ref tis) => {
2132 tis.iter().filter_map(|ti| {
2133 if let hir::ConstTraitItem(_, _) = ti.node {
2134 match self.impl_or_trait_item(self.map.local_def_id(ti.id)) {
2135 ConstTraitItem(ac) => Some(ac),
2137 self.sess.bug("associated_consts(): \
2138 non-const item found from \
2139 looking up a constant?!")
2147 ItemImpl(_, _, _, _, _, ref iis) => {
2148 iis.iter().filter_map(|ii| {
2149 if let hir::ConstImplItem(_, _) = ii.node {
2150 match self.impl_or_trait_item(self.map.local_def_id(ii.id)) {
2151 ConstTraitItem(ac) => Some(ac),
2153 self.sess.bug("associated_consts(): \
2154 non-const item found from \
2155 looking up a constant?!")
2164 self.sess.bug(&format!("associated_consts: `{:?}` is not a trait \
2169 csearch::get_associated_consts(self, id)
2173 pub fn trait_items(&self, trait_did: DefId) -> Rc<Vec<ImplOrTraitItem<'tcx>>> {
2174 let mut trait_items = self.trait_items_cache.borrow_mut();
2175 match trait_items.get(&trait_did).cloned() {
2176 Some(trait_items) => trait_items,
2178 let def_ids = self.trait_item_def_ids(trait_did);
2179 let items: Rc<Vec<ImplOrTraitItem>> =
2180 Rc::new(def_ids.iter()
2181 .map(|d| self.impl_or_trait_item(d.def_id()))
2183 trait_items.insert(trait_did, items.clone());
2189 pub fn trait_impl_polarity(&self, id: DefId) -> Option<hir::ImplPolarity> {
2190 if let Some(id) = self.map.as_local_node_id(id) {
2191 match self.map.find(id) {
2192 Some(ast_map::NodeItem(item)) => {
2194 hir::ItemImpl(_, polarity, _, _, _, _) => Some(polarity),
2201 csearch::get_impl_polarity(self, id)
2205 pub fn custom_coerce_unsized_kind(&self, did: DefId) -> adjustment::CustomCoerceUnsized {
2206 memoized(&self.custom_coerce_unsized_kinds, did, |did: DefId| {
2207 let (kind, src) = if did.krate != LOCAL_CRATE {
2208 (csearch::get_custom_coerce_unsized_kind(self, did), "external")
2216 self.sess.bug(&format!("custom_coerce_unsized_kind: \
2217 {} impl `{}` is missing its kind",
2218 src, self.item_path_str(did)));
2224 pub fn impl_or_trait_item(&self, id: DefId) -> ImplOrTraitItem<'tcx> {
2225 lookup_locally_or_in_crate_store(
2226 "impl_or_trait_items", id, &self.impl_or_trait_items,
2227 || csearch::get_impl_or_trait_item(self, id))
2230 pub fn trait_item_def_ids(&self, id: DefId) -> Rc<Vec<ImplOrTraitItemId>> {
2231 lookup_locally_or_in_crate_store(
2232 "trait_item_def_ids", id, &self.trait_item_def_ids,
2233 || Rc::new(csearch::get_trait_item_def_ids(&self.sess.cstore, id)))
2236 /// Returns the trait-ref corresponding to a given impl, or None if it is
2237 /// an inherent impl.
2238 pub fn impl_trait_ref(&self, id: DefId) -> Option<TraitRef<'tcx>> {
2239 lookup_locally_or_in_crate_store(
2240 "impl_trait_refs", id, &self.impl_trait_refs,
2241 || csearch::get_impl_trait(self, id))
2244 /// Returns whether this DefId refers to an impl
2245 pub fn is_impl(&self, id: DefId) -> bool {
2246 if let Some(id) = self.map.as_local_node_id(id) {
2247 if let Some(ast_map::NodeItem(
2248 &hir::Item { node: hir::ItemImpl(..), .. })) = self.map.find(id) {
2254 csearch::is_impl(&self.sess.cstore, id)
2258 pub fn trait_ref_to_def_id(&self, tr: &hir::TraitRef) -> DefId {
2259 self.def_map.borrow().get(&tr.ref_id).expect("no def-map entry for trait").def_id()
2262 pub fn item_path_str(&self, id: DefId) -> String {
2263 self.with_path(id, |path| ast_map::path_to_string(path))
2266 pub fn with_path<T, F>(&self, id: DefId, f: F) -> T where
2267 F: FnOnce(ast_map::PathElems) -> T,
2269 if let Some(id) = self.map.as_local_node_id(id) {
2270 self.map.with_path(id, f)
2272 f(csearch::get_item_path(self, id).iter().cloned().chain(LinkedPath::empty()))
2276 pub fn item_name(&self, id: DefId) -> ast::Name {
2277 if let Some(id) = self.map.as_local_node_id(id) {
2278 self.map.get_path_elem(id).name()
2280 csearch::get_item_name(self, id)
2284 // Register a given item type
2285 pub fn register_item_type(&self, did: DefId, ty: TypeScheme<'tcx>) {
2286 self.tcache.borrow_mut().insert(did, ty);
2289 // If the given item is in an external crate, looks up its type and adds it to
2290 // the type cache. Returns the type parameters and type.
2291 pub fn lookup_item_type(&self, did: DefId) -> TypeScheme<'tcx> {
2292 lookup_locally_or_in_crate_store(
2293 "tcache", did, &self.tcache,
2294 || csearch::get_type(self, did))
2297 /// Given the did of a trait, returns its canonical trait ref.
2298 pub fn lookup_trait_def(&self, did: DefId) -> &'tcx TraitDef<'tcx> {
2299 lookup_locally_or_in_crate_store(
2300 "trait_defs", did, &self.trait_defs,
2301 || self.alloc_trait_def(csearch::get_trait_def(self, did))
2305 /// Given the did of an ADT, return a master reference to its
2306 /// definition. Unless you are planning on fulfilling the ADT's fields,
2307 /// use lookup_adt_def instead.
2308 pub fn lookup_adt_def_master(&self, did: DefId) -> AdtDefMaster<'tcx> {
2309 lookup_locally_or_in_crate_store(
2310 "adt_defs", did, &self.adt_defs,
2311 || csearch::get_adt_def(self, did)
2315 /// Given the did of an ADT, return a reference to its definition.
2316 pub fn lookup_adt_def(&self, did: DefId) -> AdtDef<'tcx> {
2317 // when reverse-variance goes away, a transmute::<AdtDefMaster,AdtDef>
2318 // woud be needed here.
2319 self.lookup_adt_def_master(did)
2322 /// Given the did of an item, returns its full set of predicates.
2323 pub fn lookup_predicates(&self, did: DefId) -> GenericPredicates<'tcx> {
2324 lookup_locally_or_in_crate_store(
2325 "predicates", did, &self.predicates,
2326 || csearch::get_predicates(self, did))
2329 /// Given the did of a trait, returns its superpredicates.
2330 pub fn lookup_super_predicates(&self, did: DefId) -> GenericPredicates<'tcx> {
2331 lookup_locally_or_in_crate_store(
2332 "super_predicates", did, &self.super_predicates,
2333 || csearch::get_super_predicates(self, did))
2336 /// Get the attributes of a definition.
2337 pub fn get_attrs(&self, did: DefId) -> Cow<'tcx, [ast::Attribute]> {
2338 if let Some(id) = self.map.as_local_node_id(did) {
2339 Cow::Borrowed(self.map.attrs(id))
2341 Cow::Owned(csearch::get_item_attrs(&self.sess.cstore, did))
2345 /// Determine whether an item is annotated with an attribute
2346 pub fn has_attr(&self, did: DefId, attr: &str) -> bool {
2347 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2350 /// Determine whether an item is annotated with `#[repr(packed)]`
2351 pub fn lookup_packed(&self, did: DefId) -> bool {
2352 self.lookup_repr_hints(did).contains(&attr::ReprPacked)
2355 /// Determine whether an item is annotated with `#[simd]`
2356 pub fn lookup_simd(&self, did: DefId) -> bool {
2357 self.has_attr(did, "simd")
2358 || self.lookup_repr_hints(did).contains(&attr::ReprSimd)
2361 /// Obtain the representation annotation for a struct definition.
2362 pub fn lookup_repr_hints(&self, did: DefId) -> Rc<Vec<attr::ReprAttr>> {
2363 memoized(&self.repr_hint_cache, did, |did: DefId| {
2364 Rc::new(if did.is_local() {
2365 self.get_attrs(did).iter().flat_map(|meta| {
2366 attr::find_repr_attrs(self.sess.diagnostic(), meta).into_iter()
2369 csearch::get_repr_attrs(&self.sess.cstore, did)
2374 pub fn item_variances(&self, item_id: DefId) -> Rc<ItemVariances> {
2375 lookup_locally_or_in_crate_store(
2376 "item_variance_map", item_id, &self.item_variance_map,
2377 || Rc::new(csearch::get_item_variances(&self.sess.cstore, item_id)))
2380 pub fn trait_has_default_impl(&self, trait_def_id: DefId) -> bool {
2381 self.populate_implementations_for_trait_if_necessary(trait_def_id);
2383 let def = self.lookup_trait_def(trait_def_id);
2384 def.flags.get().intersects(TraitFlags::HAS_DEFAULT_IMPL)
2387 /// Records a trait-to-implementation mapping.
2388 pub fn record_trait_has_default_impl(&self, trait_def_id: DefId) {
2389 let def = self.lookup_trait_def(trait_def_id);
2390 def.flags.set(def.flags.get() | TraitFlags::HAS_DEFAULT_IMPL)
2393 /// Load primitive inherent implementations if necessary
2394 pub fn populate_implementations_for_primitive_if_necessary(&self,
2395 primitive_def_id: DefId) {
2396 if primitive_def_id.is_local() {
2400 if self.populated_external_primitive_impls.borrow().contains(&primitive_def_id) {
2404 debug!("populate_implementations_for_primitive_if_necessary: searching for {:?}",
2407 let impl_items = csearch::get_impl_items(&self.sess.cstore, primitive_def_id);
2409 // Store the implementation info.
2410 self.impl_items.borrow_mut().insert(primitive_def_id, impl_items);
2411 self.populated_external_primitive_impls.borrow_mut().insert(primitive_def_id);
2414 /// Populates the type context with all the inherent implementations for
2415 /// the given type if necessary.
2416 pub fn populate_inherent_implementations_for_type_if_necessary(&self,
2418 if type_id.is_local() {
2422 if self.populated_external_types.borrow().contains(&type_id) {
2426 debug!("populate_inherent_implementations_for_type_if_necessary: searching for {:?}",
2429 let mut inherent_impls = Vec::new();
2430 csearch::each_inherent_implementation_for_type(&self.sess.cstore, type_id, |impl_def_id| {
2431 // Record the implementation.
2432 inherent_impls.push(impl_def_id);
2434 // Store the implementation info.
2435 let impl_items = csearch::get_impl_items(&self.sess.cstore, impl_def_id);
2436 self.impl_items.borrow_mut().insert(impl_def_id, impl_items);
2439 self.inherent_impls.borrow_mut().insert(type_id, Rc::new(inherent_impls));
2440 self.populated_external_types.borrow_mut().insert(type_id);
2443 /// Populates the type context with all the implementations for the given
2444 /// trait if necessary.
2445 pub fn populate_implementations_for_trait_if_necessary(&self, trait_id: DefId) {
2446 if trait_id.is_local() {
2450 let def = self.lookup_trait_def(trait_id);
2451 if def.flags.get().intersects(TraitFlags::IMPLS_VALID) {
2455 debug!("populate_implementations_for_trait_if_necessary: searching for {:?}", def);
2457 if csearch::is_defaulted_trait(&self.sess.cstore, trait_id) {
2458 self.record_trait_has_default_impl(trait_id);
2461 csearch::each_implementation_for_trait(&self.sess.cstore, trait_id, |impl_def_id| {
2462 let impl_items = csearch::get_impl_items(&self.sess.cstore, impl_def_id);
2463 let trait_ref = self.impl_trait_ref(impl_def_id).unwrap();
2464 // Record the trait->implementation mapping.
2465 def.record_impl(self, impl_def_id, trait_ref);
2467 // For any methods that use a default implementation, add them to
2468 // the map. This is a bit unfortunate.
2469 for impl_item_def_id in &impl_items {
2470 let method_def_id = impl_item_def_id.def_id();
2471 // load impl items eagerly for convenience
2472 // FIXME: we may want to load these lazily
2473 self.impl_or_trait_item(method_def_id);
2476 // Store the implementation info.
2477 self.impl_items.borrow_mut().insert(impl_def_id, impl_items);
2480 def.flags.set(def.flags.get() | TraitFlags::IMPLS_VALID);
2483 /// Given the def_id of an impl, return the def_id of the trait it implements.
2484 /// If it implements no trait, return `None`.
2485 pub fn trait_id_of_impl(&self, def_id: DefId) -> Option<DefId> {
2486 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2489 /// If the given def ID describes a method belonging to an impl, return the
2490 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2491 pub fn impl_of_method(&self, def_id: DefId) -> Option<DefId> {
2492 if def_id.krate != LOCAL_CRATE {
2493 return match csearch::get_impl_or_trait_item(self,
2494 def_id).container() {
2495 TraitContainer(_) => None,
2496 ImplContainer(def_id) => Some(def_id),
2499 match self.impl_or_trait_items.borrow().get(&def_id).cloned() {
2500 Some(trait_item) => {
2501 match trait_item.container() {
2502 TraitContainer(_) => None,
2503 ImplContainer(def_id) => Some(def_id),
2510 /// If the given def ID describes an item belonging to a trait (either a
2511 /// default method or an implementation of a trait method), return the ID of
2512 /// the trait that the method belongs to. Otherwise, return `None`.
2513 pub fn trait_of_item(&self, def_id: DefId) -> Option<DefId> {
2514 if def_id.krate != LOCAL_CRATE {
2515 return csearch::get_trait_of_item(&self.sess.cstore, def_id, self);
2517 match self.impl_or_trait_items.borrow().get(&def_id).cloned() {
2518 Some(impl_or_trait_item) => {
2519 match impl_or_trait_item.container() {
2520 TraitContainer(def_id) => Some(def_id),
2521 ImplContainer(def_id) => self.trait_id_of_impl(def_id),
2528 /// If the given def ID describes an item belonging to a trait, (either a
2529 /// default method or an implementation of a trait method), return the ID of
2530 /// the method inside trait definition (this means that if the given def ID
2531 /// is already that of the original trait method, then the return value is
2533 /// Otherwise, return `None`.
2534 pub fn trait_item_of_item(&self, def_id: DefId) -> Option<ImplOrTraitItemId> {
2535 let impl_item = match self.impl_or_trait_items.borrow().get(&def_id) {
2536 Some(m) => m.clone(),
2537 None => return None,
2539 let name = impl_item.name();
2540 match self.trait_of_item(def_id) {
2541 Some(trait_did) => {
2542 self.trait_items(trait_did).iter()
2543 .find(|item| item.name() == name)
2544 .map(|item| item.id())
2550 /// Construct a parameter environment suitable for static contexts or other contexts where there
2551 /// are no free type/lifetime parameters in scope.
2552 pub fn empty_parameter_environment<'a>(&'a self)
2553 -> ParameterEnvironment<'a,'tcx> {
2554 ty::ParameterEnvironment { tcx: self,
2555 free_substs: Substs::empty(),
2556 caller_bounds: Vec::new(),
2557 implicit_region_bound: ty::ReEmpty,
2558 selection_cache: traits::SelectionCache::new(),
2560 // for an empty parameter
2561 // environment, there ARE no free
2562 // regions, so it shouldn't matter
2563 // what we use for the free id
2564 free_id: ast::DUMMY_NODE_ID }
2567 /// Constructs and returns a substitution that can be applied to move from
2568 /// the "outer" view of a type or method to the "inner" view.
2569 /// In general, this means converting from bound parameters to
2570 /// free parameters. Since we currently represent bound/free type
2571 /// parameters in the same way, this only has an effect on regions.
2572 pub fn construct_free_substs(&self, generics: &Generics<'tcx>,
2573 free_id: NodeId) -> Substs<'tcx> {
2575 let mut types = VecPerParamSpace::empty();
2576 for def in generics.types.as_slice() {
2577 debug!("construct_parameter_environment(): push_types_from_defs: def={:?}",
2579 types.push(def.space, self.mk_param_from_def(def));
2582 let free_id_outlive = self.region_maps.item_extent(free_id);
2584 // map bound 'a => free 'a
2585 let mut regions = VecPerParamSpace::empty();
2586 for def in generics.regions.as_slice() {
2588 ReFree(FreeRegion { scope: free_id_outlive,
2589 bound_region: BrNamed(def.def_id, def.name) });
2590 debug!("push_region_params {:?}", region);
2591 regions.push(def.space, region);
2596 regions: subst::NonerasedRegions(regions)
2600 /// See `ParameterEnvironment` struct def'n for details
2601 pub fn construct_parameter_environment<'a>(&'a self,
2603 generics: &ty::Generics<'tcx>,
2604 generic_predicates: &ty::GenericPredicates<'tcx>,
2606 -> ParameterEnvironment<'a, 'tcx>
2609 // Construct the free substs.
2612 let free_substs = self.construct_free_substs(generics, free_id);
2613 let free_id_outlive = self.region_maps.item_extent(free_id);
2616 // Compute the bounds on Self and the type parameters.
2619 let bounds = generic_predicates.instantiate(self, &free_substs);
2620 let bounds = self.liberate_late_bound_regions(free_id_outlive, &ty::Binder(bounds));
2621 let predicates = bounds.predicates.into_vec();
2623 debug!("construct_parameter_environment: free_id={:?} free_subst={:?} predicates={:?}",
2629 // Finally, we have to normalize the bounds in the environment, in
2630 // case they contain any associated type projections. This process
2631 // can yield errors if the put in illegal associated types, like
2632 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2633 // report these errors right here; this doesn't actually feel
2634 // right to me, because constructing the environment feels like a
2635 // kind of a "idempotent" action, but I'm not sure where would be
2636 // a better place. In practice, we construct environments for
2637 // every fn once during type checking, and we'll abort if there
2638 // are any errors at that point, so after type checking you can be
2639 // sure that this will succeed without errors anyway.
2642 let unnormalized_env = ty::ParameterEnvironment {
2644 free_substs: free_substs,
2645 implicit_region_bound: ty::ReScope(free_id_outlive),
2646 caller_bounds: predicates,
2647 selection_cache: traits::SelectionCache::new(),
2651 let cause = traits::ObligationCause::misc(span, free_id);
2652 traits::normalize_param_env_or_error(unnormalized_env, cause)
2655 pub fn is_method_call(&self, expr_id: NodeId) -> bool {
2656 self.tables.borrow().method_map.contains_key(&MethodCall::expr(expr_id))
2659 pub fn is_overloaded_autoderef(&self, expr_id: NodeId, autoderefs: u32) -> bool {
2660 self.tables.borrow().method_map.contains_key(&MethodCall::autoderef(expr_id,
2664 pub fn upvar_capture(&self, upvar_id: ty::UpvarId) -> Option<ty::UpvarCapture> {
2665 Some(self.tables.borrow().upvar_capture_map.get(&upvar_id).unwrap().clone())
2669 /// The category of explicit self.
2670 #[derive(Clone, Copy, Eq, PartialEq, Debug)]
2671 pub enum ExplicitSelfCategory {
2672 StaticExplicitSelfCategory,
2673 ByValueExplicitSelfCategory,
2674 ByReferenceExplicitSelfCategory(Region, hir::Mutability),
2675 ByBoxExplicitSelfCategory,
2678 /// A free variable referred to in a function.
2679 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
2680 pub struct Freevar {
2681 /// The variable being accessed free.
2684 // First span where it is accessed (there can be multiple).
2688 pub type FreevarMap = NodeMap<Vec<Freevar>>;
2690 pub type CaptureModeMap = NodeMap<hir::CaptureClause>;
2692 // Trait method resolution
2693 pub type TraitMap = NodeMap<Vec<DefId>>;
2695 // Map from the NodeId of a glob import to a list of items which are actually
2697 pub type GlobMap = HashMap<NodeId, HashSet<Name>>;
2699 impl<'tcx> ctxt<'tcx> {
2700 pub fn with_freevars<T, F>(&self, fid: NodeId, f: F) -> T where
2701 F: FnOnce(&[Freevar]) -> T,
2703 match self.freevars.borrow().get(&fid) {
2705 Some(d) => f(&d[..])
2709 pub fn make_substs_for_receiver_types(&self,
2710 trait_ref: &ty::TraitRef<'tcx>,
2711 method: &ty::Method<'tcx>)
2712 -> subst::Substs<'tcx>
2715 * Substitutes the values for the receiver's type parameters
2716 * that are found in method, leaving the method's type parameters
2720 let meth_tps: Vec<Ty> =
2721 method.generics.types.get_slice(subst::FnSpace)
2723 .map(|def| self.mk_param_from_def(def))
2725 let meth_regions: Vec<ty::Region> =
2726 method.generics.regions.get_slice(subst::FnSpace)
2728 .map(|def| def.to_early_bound_region())
2730 trait_ref.substs.clone().with_method(meth_tps, meth_regions)
2734 /// An "escaping region" is a bound region whose binder is not part of `t`.
2736 /// So, for example, consider a type like the following, which has two binders:
2738 /// for<'a> fn(x: for<'b> fn(&'a isize, &'b isize))
2739 /// ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ outer scope
2740 /// ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ inner scope
2742 /// This type has *bound regions* (`'a`, `'b`), but it does not have escaping regions, because the
2743 /// binders of both `'a` and `'b` are part of the type itself. However, if we consider the *inner
2744 /// fn type*, that type has an escaping region: `'a`.
2746 /// Note that what I'm calling an "escaping region" is often just called a "free region". However,
2747 /// we already use the term "free region". It refers to the regions that we use to represent bound
2748 /// regions on a fn definition while we are typechecking its body.
2750 /// To clarify, conceptually there is no particular difference between an "escaping" region and a
2751 /// "free" region. However, there is a big difference in practice. Basically, when "entering" a
2752 /// binding level, one is generally required to do some sort of processing to a bound region, such
2753 /// as replacing it with a fresh/skolemized region, or making an entry in the environment to
2754 /// represent the scope to which it is attached, etc. An escaping region represents a bound region
2755 /// for which this processing has not yet been done.
2756 pub trait RegionEscape {
2757 fn has_escaping_regions(&self) -> bool {
2758 self.has_regions_escaping_depth(0)
2761 fn has_regions_escaping_depth(&self, depth: u32) -> bool;
2764 pub trait HasTypeFlags {
2765 fn has_type_flags(&self, flags: TypeFlags) -> bool;
2766 fn has_projection_types(&self) -> bool {
2767 self.has_type_flags(TypeFlags::HAS_PROJECTION)
2769 fn references_error(&self) -> bool {
2770 self.has_type_flags(TypeFlags::HAS_TY_ERR)
2772 fn has_param_types(&self) -> bool {
2773 self.has_type_flags(TypeFlags::HAS_PARAMS)
2775 fn has_self_ty(&self) -> bool {
2776 self.has_type_flags(TypeFlags::HAS_SELF)
2778 fn has_infer_types(&self) -> bool {
2779 self.has_type_flags(TypeFlags::HAS_TY_INFER)
2781 fn needs_infer(&self) -> bool {
2782 self.has_type_flags(TypeFlags::HAS_TY_INFER | TypeFlags::HAS_RE_INFER)
2784 fn needs_subst(&self) -> bool {
2785 self.has_type_flags(TypeFlags::NEEDS_SUBST)
2787 fn has_closure_types(&self) -> bool {
2788 self.has_type_flags(TypeFlags::HAS_TY_CLOSURE)
2790 fn has_erasable_regions(&self) -> bool {
2791 self.has_type_flags(TypeFlags::HAS_RE_EARLY_BOUND |
2792 TypeFlags::HAS_RE_INFER |
2793 TypeFlags::HAS_FREE_REGIONS)
2795 /// Indicates whether this value references only 'global'
2796 /// types/lifetimes that are the same regardless of what fn we are
2797 /// in. This is used for caching. Errs on the side of returning
2799 fn is_global(&self) -> bool {
2800 !self.has_type_flags(TypeFlags::HAS_LOCAL_NAMES)