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::Variance::*;
13 pub use self::DtorKind::*;
14 pub use self::ImplOrTraitItemContainer::*;
15 pub use self::BorrowKind::*;
16 pub use self::ImplOrTraitItem::*;
17 pub use self::IntVarValue::*;
18 pub use self::LvaluePreference::*;
19 pub use self::fold::TypeFoldable;
21 use dep_graph::{self, DepNode};
22 use front::map as ast_map;
23 use front::map::LinkedPath;
25 use middle::cstore::{self, CrateStore, LOCAL_CRATE};
26 use middle::def::{self, Def, ExportMap};
27 use middle::def_id::DefId;
28 use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
29 use middle::region::{CodeExtent};
30 use middle::subst::{self, Subst, Substs, VecPerParamSpace};
33 use middle::ty::fold::TypeFolder;
34 use middle::ty::walk::TypeWalker;
35 use util::common::MemoizationMap;
36 use util::nodemap::{NodeMap, NodeSet};
37 use util::nodemap::FnvHashMap;
39 use serialize::{Encodable, Encoder, Decodable, Decoder};
40 use std::borrow::{Borrow, Cow};
42 use std::hash::{Hash, Hasher};
46 use std::vec::IntoIter;
47 use std::collections::{HashMap, HashSet};
48 use syntax::ast::{self, CrateNum, Name, NodeId};
49 use syntax::attr::{self, AttrMetaMethods};
50 use syntax::codemap::{DUMMY_SP, Span};
51 use syntax::parse::token::InternedString;
54 use rustc_front::hir::{ItemImpl, ItemTrait};
55 use rustc_front::intravisit::Visitor;
57 pub use self::sty::{Binder, DebruijnIndex};
58 pub use self::sty::{BuiltinBound, BuiltinBounds, ExistentialBounds};
59 pub use self::sty::{BareFnTy, FnSig, PolyFnSig, FnOutput, PolyFnOutput};
60 pub use self::sty::{ClosureTy, InferTy, ParamTy, ProjectionTy, TraitTy};
61 pub use self::sty::{ClosureSubsts, TypeAndMut};
62 pub use self::sty::{TraitRef, TypeVariants, PolyTraitRef};
63 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
64 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid, SkolemizedRegionVid};
65 pub use self::sty::BoundRegion::*;
66 pub use self::sty::FnOutput::*;
67 pub use self::sty::InferTy::*;
68 pub use self::sty::Region::*;
69 pub use self::sty::TypeVariants::*;
71 pub use self::sty::BuiltinBound::Send as BoundSend;
72 pub use self::sty::BuiltinBound::Sized as BoundSized;
73 pub use self::sty::BuiltinBound::Copy as BoundCopy;
74 pub use self::sty::BuiltinBound::Sync as BoundSync;
76 pub use self::contents::TypeContents;
77 pub use self::context::{ctxt, tls};
78 pub use self::context::{CtxtArenas, Lift, Tables};
80 pub use self::trait_def::{TraitDef, TraitFlags};
100 mod structural_impls;
104 pub const INITIAL_DISCRIMINANT_VALUE: Disr = 0;
108 /// The complete set of all analyses described in this module. This is
109 /// produced by the driver and fed to trans and later passes.
110 pub struct CrateAnalysis<'a> {
111 pub export_map: ExportMap,
112 pub access_levels: middle::privacy::AccessLevels,
113 pub reachable: NodeSet,
115 pub glob_map: Option<GlobMap>,
118 #[derive(Copy, Clone)]
125 pub fn is_present(&self) -> bool {
127 TraitDtor(..) => true,
132 pub fn has_drop_flag(&self) -> bool {
135 &TraitDtor(flag) => flag
140 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
141 pub enum ImplOrTraitItemContainer {
142 TraitContainer(DefId),
143 ImplContainer(DefId),
146 impl ImplOrTraitItemContainer {
147 pub fn id(&self) -> DefId {
149 TraitContainer(id) => id,
150 ImplContainer(id) => id,
156 pub enum ImplOrTraitItem<'tcx> {
157 ConstTraitItem(Rc<AssociatedConst<'tcx>>),
158 MethodTraitItem(Rc<Method<'tcx>>),
159 TypeTraitItem(Rc<AssociatedType<'tcx>>),
162 impl<'tcx> ImplOrTraitItem<'tcx> {
163 fn id(&self) -> ImplOrTraitItemId {
165 ConstTraitItem(ref associated_const) => {
166 ConstTraitItemId(associated_const.def_id)
168 MethodTraitItem(ref method) => MethodTraitItemId(method.def_id),
169 TypeTraitItem(ref associated_type) => {
170 TypeTraitItemId(associated_type.def_id)
175 pub fn def_id(&self) -> DefId {
177 ConstTraitItem(ref associated_const) => associated_const.def_id,
178 MethodTraitItem(ref method) => method.def_id,
179 TypeTraitItem(ref associated_type) => associated_type.def_id,
183 pub fn name(&self) -> Name {
185 ConstTraitItem(ref associated_const) => associated_const.name,
186 MethodTraitItem(ref method) => method.name,
187 TypeTraitItem(ref associated_type) => associated_type.name,
191 pub fn vis(&self) -> hir::Visibility {
193 ConstTraitItem(ref associated_const) => associated_const.vis,
194 MethodTraitItem(ref method) => method.vis,
195 TypeTraitItem(ref associated_type) => associated_type.vis,
199 pub fn container(&self) -> ImplOrTraitItemContainer {
201 ConstTraitItem(ref associated_const) => associated_const.container,
202 MethodTraitItem(ref method) => method.container,
203 TypeTraitItem(ref associated_type) => associated_type.container,
207 pub fn as_opt_method(&self) -> Option<Rc<Method<'tcx>>> {
209 MethodTraitItem(ref m) => Some((*m).clone()),
215 #[derive(Clone, Copy, Debug)]
216 pub enum ImplOrTraitItemId {
217 ConstTraitItemId(DefId),
218 MethodTraitItemId(DefId),
219 TypeTraitItemId(DefId),
222 impl ImplOrTraitItemId {
223 pub fn def_id(&self) -> DefId {
225 ConstTraitItemId(def_id) => def_id,
226 MethodTraitItemId(def_id) => def_id,
227 TypeTraitItemId(def_id) => def_id,
232 #[derive(Clone, Debug)]
233 pub struct Method<'tcx> {
235 pub generics: Generics<'tcx>,
236 pub predicates: GenericPredicates<'tcx>,
237 pub fty: BareFnTy<'tcx>,
238 pub explicit_self: ExplicitSelfCategory,
239 pub vis: hir::Visibility,
241 pub container: ImplOrTraitItemContainer,
244 impl<'tcx> Method<'tcx> {
245 pub fn new(name: Name,
246 generics: ty::Generics<'tcx>,
247 predicates: GenericPredicates<'tcx>,
249 explicit_self: ExplicitSelfCategory,
250 vis: hir::Visibility,
252 container: ImplOrTraitItemContainer)
257 predicates: predicates,
259 explicit_self: explicit_self,
262 container: container,
266 pub fn container_id(&self) -> DefId {
267 match self.container {
268 TraitContainer(id) => id,
269 ImplContainer(id) => id,
274 impl<'tcx> PartialEq for Method<'tcx> {
276 fn eq(&self, other: &Self) -> bool { self.def_id == other.def_id }
279 impl<'tcx> Eq for Method<'tcx> {}
281 impl<'tcx> Hash for Method<'tcx> {
283 fn hash<H: Hasher>(&self, s: &mut H) {
288 #[derive(Clone, Copy, Debug)]
289 pub struct AssociatedConst<'tcx> {
292 pub vis: hir::Visibility,
294 pub container: ImplOrTraitItemContainer,
298 #[derive(Clone, Copy, Debug)]
299 pub struct AssociatedType<'tcx> {
301 pub ty: Option<Ty<'tcx>>,
302 pub vis: hir::Visibility,
304 pub container: ImplOrTraitItemContainer,
307 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable)]
308 pub struct ItemVariances {
309 pub types: VecPerParamSpace<Variance>,
310 pub regions: VecPerParamSpace<Variance>,
313 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
315 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
316 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
317 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
318 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
321 #[derive(Clone, Copy, Debug)]
322 pub struct MethodCallee<'tcx> {
323 /// Impl method ID, for inherent methods, or trait method ID, otherwise.
326 pub substs: &'tcx subst::Substs<'tcx>
329 /// With method calls, we store some extra information in
330 /// side tables (i.e method_map). We use
331 /// MethodCall as a key to index into these tables instead of
332 /// just directly using the expression's NodeId. The reason
333 /// for this being that we may apply adjustments (coercions)
334 /// with the resulting expression also needing to use the
335 /// side tables. The problem with this is that we don't
336 /// assign a separate NodeId to this new expression
337 /// and so it would clash with the base expression if both
338 /// needed to add to the side tables. Thus to disambiguate
339 /// we also keep track of whether there's an adjustment in
341 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
342 pub struct MethodCall {
348 pub fn expr(id: NodeId) -> MethodCall {
355 pub fn autoderef(expr_id: NodeId, autoderef: u32) -> MethodCall {
358 autoderef: 1 + autoderef
363 // maps from an expression id that corresponds to a method call to the details
364 // of the method to be invoked
365 pub type MethodMap<'tcx> = FnvHashMap<MethodCall, MethodCallee<'tcx>>;
367 // Contains information needed to resolve types and (in the future) look up
368 // the types of AST nodes.
369 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
370 pub struct CReaderCacheKey {
375 /// A restriction that certain types must be the same size. The use of
376 /// `transmute` gives rise to these restrictions. These generally
377 /// cannot be checked until trans; therefore, each call to `transmute`
378 /// will push one or more such restriction into the
379 /// `transmute_restrictions` vector during `intrinsicck`. They are
380 /// then checked during `trans` by the fn `check_intrinsics`.
381 #[derive(Copy, Clone)]
382 pub struct TransmuteRestriction<'tcx> {
383 /// The span whence the restriction comes.
386 /// The type being transmuted from.
387 pub original_from: Ty<'tcx>,
389 /// The type being transmuted to.
390 pub original_to: Ty<'tcx>,
392 /// The type being transmuted from, with all type parameters
393 /// substituted for an arbitrary representative. Not to be shown
395 pub substituted_from: Ty<'tcx>,
397 /// The type being transmuted to, with all type parameters
398 /// substituted for an arbitrary representative. Not to be shown
400 pub substituted_to: Ty<'tcx>,
402 /// NodeId of the transmute intrinsic.
406 /// Describes the fragment-state associated with a NodeId.
408 /// Currently only unfragmented paths have entries in the table,
409 /// but longer-term this enum is expected to expand to also
410 /// include data for fragmented paths.
411 #[derive(Copy, Clone, Debug)]
412 pub enum FragmentInfo {
413 Moved { var: NodeId, move_expr: NodeId },
414 Assigned { var: NodeId, assign_expr: NodeId, assignee_id: NodeId },
417 // Flags that we track on types. These flags are propagated upwards
418 // through the type during type construction, so that we can quickly
419 // check whether the type has various kinds of types in it without
420 // recursing over the type itself.
422 flags TypeFlags: u32 {
423 const HAS_PARAMS = 1 << 0,
424 const HAS_SELF = 1 << 1,
425 const HAS_TY_INFER = 1 << 2,
426 const HAS_RE_INFER = 1 << 3,
427 const HAS_RE_EARLY_BOUND = 1 << 4,
428 const HAS_FREE_REGIONS = 1 << 5,
429 const HAS_TY_ERR = 1 << 6,
430 const HAS_PROJECTION = 1 << 7,
431 const HAS_TY_CLOSURE = 1 << 8,
433 // true if there are "names" of types and regions and so forth
434 // that are local to a particular fn
435 const HAS_LOCAL_NAMES = 1 << 9,
437 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
438 TypeFlags::HAS_SELF.bits |
439 TypeFlags::HAS_RE_EARLY_BOUND.bits,
441 // Flags representing the nominal content of a type,
442 // computed by FlagsComputation. If you add a new nominal
443 // flag, it should be added here too.
444 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
445 TypeFlags::HAS_SELF.bits |
446 TypeFlags::HAS_TY_INFER.bits |
447 TypeFlags::HAS_RE_INFER.bits |
448 TypeFlags::HAS_RE_EARLY_BOUND.bits |
449 TypeFlags::HAS_FREE_REGIONS.bits |
450 TypeFlags::HAS_TY_ERR.bits |
451 TypeFlags::HAS_PROJECTION.bits |
452 TypeFlags::HAS_TY_CLOSURE.bits |
453 TypeFlags::HAS_LOCAL_NAMES.bits,
455 // Caches for type_is_sized, type_moves_by_default
456 const SIZEDNESS_CACHED = 1 << 16,
457 const IS_SIZED = 1 << 17,
458 const MOVENESS_CACHED = 1 << 18,
459 const MOVES_BY_DEFAULT = 1 << 19,
463 pub struct TyS<'tcx> {
464 pub sty: TypeVariants<'tcx>,
465 pub flags: Cell<TypeFlags>,
467 // the maximal depth of any bound regions appearing in this type.
471 impl<'tcx> PartialEq for TyS<'tcx> {
473 fn eq(&self, other: &TyS<'tcx>) -> bool {
474 // (self as *const _) == (other as *const _)
475 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
478 impl<'tcx> Eq for TyS<'tcx> {}
480 impl<'tcx> Hash for TyS<'tcx> {
481 fn hash<H: Hasher>(&self, s: &mut H) {
482 (self as *const TyS).hash(s)
486 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
488 impl<'tcx> Encodable for Ty<'tcx> {
489 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
490 cstore::tls::with_encoding_context(s, |ecx, rbml_w| {
491 ecx.encode_ty(rbml_w, *self);
497 impl<'tcx> Decodable for Ty<'tcx> {
498 fn decode<D: Decoder>(d: &mut D) -> Result<Ty<'tcx>, D::Error> {
499 cstore::tls::with_decoding_context(d, |dcx, rbml_r| {
500 Ok(dcx.decode_ty(rbml_r))
506 /// Upvars do not get their own node-id. Instead, we use the pair of
507 /// the original var id (that is, the root variable that is referenced
508 /// by the upvar) and the id of the closure expression.
509 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
512 pub closure_expr_id: NodeId,
515 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
516 pub enum BorrowKind {
517 /// Data must be immutable and is aliasable.
520 /// Data must be immutable but not aliasable. This kind of borrow
521 /// cannot currently be expressed by the user and is used only in
522 /// implicit closure bindings. It is needed when you the closure
523 /// is borrowing or mutating a mutable referent, e.g.:
525 /// let x: &mut isize = ...;
526 /// let y = || *x += 5;
528 /// If we were to try to translate this closure into a more explicit
529 /// form, we'd encounter an error with the code as written:
531 /// struct Env { x: & &mut isize }
532 /// let x: &mut isize = ...;
533 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
534 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
536 /// This is then illegal because you cannot mutate a `&mut` found
537 /// in an aliasable location. To solve, you'd have to translate with
538 /// an `&mut` borrow:
540 /// struct Env { x: & &mut isize }
541 /// let x: &mut isize = ...;
542 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
543 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
545 /// Now the assignment to `**env.x` is legal, but creating a
546 /// mutable pointer to `x` is not because `x` is not mutable. We
547 /// could fix this by declaring `x` as `let mut x`. This is ok in
548 /// user code, if awkward, but extra weird for closures, since the
549 /// borrow is hidden.
551 /// So we introduce a "unique imm" borrow -- the referent is
552 /// immutable, but not aliasable. This solves the problem. For
553 /// simplicity, we don't give users the way to express this
554 /// borrow, it's just used when translating closures.
557 /// Data is mutable and not aliasable.
561 /// Information describing the capture of an upvar. This is computed
562 /// during `typeck`, specifically by `regionck`.
563 #[derive(PartialEq, Clone, Debug, Copy)]
564 pub enum UpvarCapture {
565 /// Upvar is captured by value. This is always true when the
566 /// closure is labeled `move`, but can also be true in other cases
567 /// depending on inference.
570 /// Upvar is captured by reference.
574 #[derive(PartialEq, Clone, Copy)]
575 pub struct UpvarBorrow {
576 /// The kind of borrow: by-ref upvars have access to shared
577 /// immutable borrows, which are not part of the normal language
579 pub kind: BorrowKind,
581 /// Region of the resulting reference.
582 pub region: ty::Region,
585 pub type UpvarCaptureMap = FnvHashMap<UpvarId, UpvarCapture>;
587 #[derive(Copy, Clone)]
588 pub struct ClosureUpvar<'tcx> {
594 #[derive(Clone, Copy, PartialEq)]
595 pub enum IntVarValue {
597 UintType(ast::UintTy),
600 /// Default region to use for the bound of objects that are
601 /// supplied as the value for this type parameter. This is derived
602 /// from `T:'a` annotations appearing in the type definition. If
603 /// this is `None`, then the default is inherited from the
604 /// surrounding context. See RFC #599 for details.
605 #[derive(Copy, Clone)]
606 pub enum ObjectLifetimeDefault {
607 /// Require an explicit annotation. Occurs when multiple
608 /// `T:'a` constraints are found.
611 /// Use the base default, typically 'static, but in a fn body it is a fresh variable
614 /// Use the given region as the default.
619 pub struct TypeParameterDef<'tcx> {
622 pub space: subst::ParamSpace,
624 pub default_def_id: DefId, // for use in error reporing about defaults
625 pub default: Option<Ty<'tcx>>,
626 pub object_lifetime_default: ObjectLifetimeDefault,
630 pub struct RegionParameterDef {
633 pub space: subst::ParamSpace,
635 pub bounds: Vec<ty::Region>,
638 impl RegionParameterDef {
639 pub fn to_early_bound_region(&self) -> ty::Region {
640 ty::ReEarlyBound(ty::EarlyBoundRegion {
646 pub fn to_bound_region(&self) -> ty::BoundRegion {
647 ty::BoundRegion::BrNamed(self.def_id, self.name)
651 /// Information about the formal type/lifetime parameters associated
652 /// with an item or method. Analogous to hir::Generics.
653 #[derive(Clone, Debug)]
654 pub struct Generics<'tcx> {
655 pub types: VecPerParamSpace<TypeParameterDef<'tcx>>,
656 pub regions: VecPerParamSpace<RegionParameterDef>,
659 impl<'tcx> Generics<'tcx> {
660 pub fn empty() -> Generics<'tcx> {
662 types: VecPerParamSpace::empty(),
663 regions: VecPerParamSpace::empty(),
667 pub fn is_empty(&self) -> bool {
668 self.types.is_empty() && self.regions.is_empty()
671 pub fn has_type_params(&self, space: subst::ParamSpace) -> bool {
672 !self.types.is_empty_in(space)
675 pub fn has_region_params(&self, space: subst::ParamSpace) -> bool {
676 !self.regions.is_empty_in(space)
680 /// Bounds on generics.
682 pub struct GenericPredicates<'tcx> {
683 pub predicates: VecPerParamSpace<Predicate<'tcx>>,
686 impl<'tcx> GenericPredicates<'tcx> {
687 pub fn empty() -> GenericPredicates<'tcx> {
689 predicates: VecPerParamSpace::empty(),
693 pub fn instantiate(&self, tcx: &ctxt<'tcx>, substs: &Substs<'tcx>)
694 -> InstantiatedPredicates<'tcx> {
695 InstantiatedPredicates {
696 predicates: self.predicates.subst(tcx, substs),
700 pub fn instantiate_supertrait(&self,
702 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
703 -> InstantiatedPredicates<'tcx>
705 InstantiatedPredicates {
706 predicates: self.predicates.map(|pred| pred.subst_supertrait(tcx, poly_trait_ref))
711 #[derive(Clone, PartialEq, Eq, Hash)]
712 pub enum Predicate<'tcx> {
713 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
714 /// the `Self` type of the trait reference and `A`, `B`, and `C`
715 /// would be the parameters in the `TypeSpace`.
716 Trait(PolyTraitPredicate<'tcx>),
718 /// where `T1 == T2`.
719 Equate(PolyEquatePredicate<'tcx>),
722 RegionOutlives(PolyRegionOutlivesPredicate),
725 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
727 /// where <T as TraitRef>::Name == X, approximately.
728 /// See `ProjectionPredicate` struct for details.
729 Projection(PolyProjectionPredicate<'tcx>),
732 WellFormed(Ty<'tcx>),
734 /// trait must be object-safe
738 impl<'tcx> Predicate<'tcx> {
739 /// Performs a substitution suitable for going from a
740 /// poly-trait-ref to supertraits that must hold if that
741 /// poly-trait-ref holds. This is slightly different from a normal
742 /// substitution in terms of what happens with bound regions. See
743 /// lengthy comment below for details.
744 pub fn subst_supertrait(&self,
746 trait_ref: &ty::PolyTraitRef<'tcx>)
747 -> ty::Predicate<'tcx>
749 // The interaction between HRTB and supertraits is not entirely
750 // obvious. Let me walk you (and myself) through an example.
752 // Let's start with an easy case. Consider two traits:
754 // trait Foo<'a> : Bar<'a,'a> { }
755 // trait Bar<'b,'c> { }
757 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
758 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
759 // knew that `Foo<'x>` (for any 'x) then we also know that
760 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
761 // normal substitution.
763 // In terms of why this is sound, the idea is that whenever there
764 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
765 // holds. So if there is an impl of `T:Foo<'a>` that applies to
766 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
769 // Another example to be careful of is this:
771 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
772 // trait Bar1<'b,'c> { }
774 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
775 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
776 // reason is similar to the previous example: any impl of
777 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
778 // basically we would want to collapse the bound lifetimes from
779 // the input (`trait_ref`) and the supertraits.
781 // To achieve this in practice is fairly straightforward. Let's
782 // consider the more complicated scenario:
784 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
785 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
786 // where both `'x` and `'b` would have a DB index of 1.
787 // The substitution from the input trait-ref is therefore going to be
788 // `'a => 'x` (where `'x` has a DB index of 1).
789 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
790 // early-bound parameter and `'b' is a late-bound parameter with a
792 // - If we replace `'a` with `'x` from the input, it too will have
793 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
794 // just as we wanted.
796 // There is only one catch. If we just apply the substitution `'a
797 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
798 // adjust the DB index because we substituting into a binder (it
799 // tries to be so smart...) resulting in `for<'x> for<'b>
800 // Bar1<'x,'b>` (we have no syntax for this, so use your
801 // imagination). Basically the 'x will have DB index of 2 and 'b
802 // will have DB index of 1. Not quite what we want. So we apply
803 // the substitution to the *contents* of the trait reference,
804 // rather than the trait reference itself (put another way, the
805 // substitution code expects equal binding levels in the values
806 // from the substitution and the value being substituted into, and
807 // this trick achieves that).
809 let substs = &trait_ref.0.substs;
811 Predicate::Trait(ty::Binder(ref data)) =>
812 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
813 Predicate::Equate(ty::Binder(ref data)) =>
814 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
815 Predicate::RegionOutlives(ty::Binder(ref data)) =>
816 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
817 Predicate::TypeOutlives(ty::Binder(ref data)) =>
818 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
819 Predicate::Projection(ty::Binder(ref data)) =>
820 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
821 Predicate::WellFormed(data) =>
822 Predicate::WellFormed(data.subst(tcx, substs)),
823 Predicate::ObjectSafe(trait_def_id) =>
824 Predicate::ObjectSafe(trait_def_id),
829 #[derive(Clone, PartialEq, Eq, Hash)]
830 pub struct TraitPredicate<'tcx> {
831 pub trait_ref: TraitRef<'tcx>
833 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
835 impl<'tcx> TraitPredicate<'tcx> {
836 pub fn def_id(&self) -> DefId {
837 self.trait_ref.def_id
840 /// Creates the dep-node for selecting/evaluating this trait reference.
841 fn dep_node(&self) -> DepNode {
842 DepNode::TraitSelect(self.def_id())
845 pub fn input_types(&self) -> &[Ty<'tcx>] {
846 self.trait_ref.substs.types.as_slice()
849 pub fn self_ty(&self) -> Ty<'tcx> {
850 self.trait_ref.self_ty()
854 impl<'tcx> PolyTraitPredicate<'tcx> {
855 pub fn def_id(&self) -> DefId {
856 // ok to skip binder since trait def-id does not care about regions
860 pub fn dep_node(&self) -> DepNode {
861 // ok to skip binder since depnode does not care about regions
866 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
867 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
868 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
870 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
871 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
872 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
873 pub type PolyRegionOutlivesPredicate = PolyOutlivesPredicate<ty::Region, ty::Region>;
874 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region>;
876 /// This kind of predicate has no *direct* correspondent in the
877 /// syntax, but it roughly corresponds to the syntactic forms:
879 /// 1. `T : TraitRef<..., Item=Type>`
880 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
882 /// In particular, form #1 is "desugared" to the combination of a
883 /// normal trait predicate (`T : TraitRef<...>`) and one of these
884 /// predicates. Form #2 is a broader form in that it also permits
885 /// equality between arbitrary types. Processing an instance of Form
886 /// #2 eventually yields one of these `ProjectionPredicate`
887 /// instances to normalize the LHS.
888 #[derive(Clone, PartialEq, Eq, Hash)]
889 pub struct ProjectionPredicate<'tcx> {
890 pub projection_ty: ProjectionTy<'tcx>,
894 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
896 impl<'tcx> PolyProjectionPredicate<'tcx> {
897 pub fn item_name(&self) -> Name {
898 self.0.projection_ty.item_name // safe to skip the binder to access a name
901 pub fn sort_key(&self) -> (DefId, Name) {
902 self.0.projection_ty.sort_key()
906 pub trait ToPolyTraitRef<'tcx> {
907 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
910 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
911 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
912 assert!(!self.has_escaping_regions());
913 ty::Binder(self.clone())
917 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
918 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
919 self.map_bound_ref(|trait_pred| trait_pred.trait_ref.clone())
923 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
924 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
925 // Note: unlike with TraitRef::to_poly_trait_ref(),
926 // self.0.trait_ref is permitted to have escaping regions.
927 // This is because here `self` has a `Binder` and so does our
928 // return value, so we are preserving the number of binding
930 ty::Binder(self.0.projection_ty.trait_ref.clone())
934 pub trait ToPredicate<'tcx> {
935 fn to_predicate(&self) -> Predicate<'tcx>;
938 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
939 fn to_predicate(&self) -> Predicate<'tcx> {
940 // we're about to add a binder, so let's check that we don't
941 // accidentally capture anything, or else that might be some
942 // weird debruijn accounting.
943 assert!(!self.has_escaping_regions());
945 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
946 trait_ref: self.clone()
951 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
952 fn to_predicate(&self) -> Predicate<'tcx> {
953 ty::Predicate::Trait(self.to_poly_trait_predicate())
957 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
958 fn to_predicate(&self) -> Predicate<'tcx> {
959 Predicate::Equate(self.clone())
963 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate {
964 fn to_predicate(&self) -> Predicate<'tcx> {
965 Predicate::RegionOutlives(self.clone())
969 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
970 fn to_predicate(&self) -> Predicate<'tcx> {
971 Predicate::TypeOutlives(self.clone())
975 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
976 fn to_predicate(&self) -> Predicate<'tcx> {
977 Predicate::Projection(self.clone())
981 impl<'tcx> Predicate<'tcx> {
982 /// Iterates over the types in this predicate. Note that in all
983 /// cases this is skipping over a binder, so late-bound regions
984 /// with depth 0 are bound by the predicate.
985 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
986 let vec: Vec<_> = match *self {
987 ty::Predicate::Trait(ref data) => {
988 data.0.trait_ref.substs.types.as_slice().to_vec()
990 ty::Predicate::Equate(ty::Binder(ref data)) => {
993 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
996 ty::Predicate::RegionOutlives(..) => {
999 ty::Predicate::Projection(ref data) => {
1000 let trait_inputs = data.0.projection_ty.trait_ref.substs.types.as_slice();
1003 .chain(Some(data.0.ty))
1006 ty::Predicate::WellFormed(data) => {
1009 ty::Predicate::ObjectSafe(_trait_def_id) => {
1014 // The only reason to collect into a vector here is that I was
1015 // too lazy to make the full (somewhat complicated) iterator
1016 // type that would be needed here. But I wanted this fn to
1017 // return an iterator conceptually, rather than a `Vec`, so as
1018 // to be closer to `Ty::walk`.
1022 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1024 Predicate::Trait(ref t) => {
1025 Some(t.to_poly_trait_ref())
1027 Predicate::Projection(..) |
1028 Predicate::Equate(..) |
1029 Predicate::RegionOutlives(..) |
1030 Predicate::WellFormed(..) |
1031 Predicate::ObjectSafe(..) |
1032 Predicate::TypeOutlives(..) => {
1039 /// Represents the bounds declared on a particular set of type
1040 /// parameters. Should eventually be generalized into a flag list of
1041 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1042 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1043 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1044 /// the `GenericPredicates` are expressed in terms of the bound type
1045 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1046 /// represented a set of bounds for some particular instantiation,
1047 /// meaning that the generic parameters have been substituted with
1052 /// struct Foo<T,U:Bar<T>> { ... }
1054 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1055 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1056 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1057 /// [usize:Bar<isize>]]`.
1059 pub struct InstantiatedPredicates<'tcx> {
1060 pub predicates: VecPerParamSpace<Predicate<'tcx>>,
1063 impl<'tcx> InstantiatedPredicates<'tcx> {
1064 pub fn empty() -> InstantiatedPredicates<'tcx> {
1065 InstantiatedPredicates { predicates: VecPerParamSpace::empty() }
1068 pub fn is_empty(&self) -> bool {
1069 self.predicates.is_empty()
1073 impl<'tcx> TraitRef<'tcx> {
1074 pub fn new(def_id: DefId, substs: &'tcx Substs<'tcx>) -> TraitRef<'tcx> {
1075 TraitRef { def_id: def_id, substs: substs }
1078 pub fn self_ty(&self) -> Ty<'tcx> {
1079 self.substs.self_ty().unwrap()
1082 pub fn input_types(&self) -> &[Ty<'tcx>] {
1083 // Select only the "input types" from a trait-reference. For
1084 // now this is all the types that appear in the
1085 // trait-reference, but it should eventually exclude
1086 // associated types.
1087 self.substs.types.as_slice()
1091 /// When type checking, we use the `ParameterEnvironment` to track
1092 /// details about the type/lifetime parameters that are in scope.
1093 /// It primarily stores the bounds information.
1095 /// Note: This information might seem to be redundant with the data in
1096 /// `tcx.ty_param_defs`, but it is not. That table contains the
1097 /// parameter definitions from an "outside" perspective, but this
1098 /// struct will contain the bounds for a parameter as seen from inside
1099 /// the function body. Currently the only real distinction is that
1100 /// bound lifetime parameters are replaced with free ones, but in the
1101 /// future I hope to refine the representation of types so as to make
1102 /// more distinctions clearer.
1104 pub struct ParameterEnvironment<'a, 'tcx:'a> {
1105 pub tcx: &'a ctxt<'tcx>,
1107 /// See `construct_free_substs` for details.
1108 pub free_substs: Substs<'tcx>,
1110 /// Each type parameter has an implicit region bound that
1111 /// indicates it must outlive at least the function body (the user
1112 /// may specify stronger requirements). This field indicates the
1113 /// region of the callee.
1114 pub implicit_region_bound: ty::Region,
1116 /// Obligations that the caller must satisfy. This is basically
1117 /// the set of bounds on the in-scope type parameters, translated
1118 /// into Obligations, and elaborated and normalized.
1119 pub caller_bounds: Vec<ty::Predicate<'tcx>>,
1121 /// Caches the results of trait selection. This cache is used
1122 /// for things that have to do with the parameters in scope.
1123 pub selection_cache: traits::SelectionCache<'tcx>,
1125 /// Caches the results of trait evaluation.
1126 pub evaluation_cache: traits::EvaluationCache<'tcx>,
1128 /// Scope that is attached to free regions for this scope. This
1129 /// is usually the id of the fn body, but for more abstract scopes
1130 /// like structs we often use the node-id of the struct.
1132 /// FIXME(#3696). It would be nice to refactor so that free
1133 /// regions don't have this implicit scope and instead introduce
1134 /// relationships in the environment.
1135 pub free_id_outlive: CodeExtent,
1138 impl<'a, 'tcx> ParameterEnvironment<'a, 'tcx> {
1139 pub fn with_caller_bounds(&self,
1140 caller_bounds: Vec<ty::Predicate<'tcx>>)
1141 -> ParameterEnvironment<'a,'tcx>
1143 ParameterEnvironment {
1145 free_substs: self.free_substs.clone(),
1146 implicit_region_bound: self.implicit_region_bound,
1147 caller_bounds: caller_bounds,
1148 selection_cache: traits::SelectionCache::new(),
1149 evaluation_cache: traits::EvaluationCache::new(),
1150 free_id_outlive: self.free_id_outlive,
1154 pub fn for_item(cx: &'a ctxt<'tcx>, id: NodeId) -> ParameterEnvironment<'a, 'tcx> {
1155 match cx.map.find(id) {
1156 Some(ast_map::NodeImplItem(ref impl_item)) => {
1157 match impl_item.node {
1158 hir::ImplItemKind::Type(_) => {
1159 // associated types don't have their own entry (for some reason),
1160 // so for now just grab environment for the impl
1161 let impl_id = cx.map.get_parent(id);
1162 let impl_def_id = cx.map.local_def_id(impl_id);
1163 let scheme = cx.lookup_item_type(impl_def_id);
1164 let predicates = cx.lookup_predicates(impl_def_id);
1165 cx.construct_parameter_environment(impl_item.span,
1168 cx.region_maps.item_extent(id))
1170 hir::ImplItemKind::Const(_, _) => {
1171 let def_id = cx.map.local_def_id(id);
1172 let scheme = cx.lookup_item_type(def_id);
1173 let predicates = cx.lookup_predicates(def_id);
1174 cx.construct_parameter_environment(impl_item.span,
1177 cx.region_maps.item_extent(id))
1179 hir::ImplItemKind::Method(_, ref body) => {
1180 let method_def_id = cx.map.local_def_id(id);
1181 match cx.impl_or_trait_item(method_def_id) {
1182 MethodTraitItem(ref method_ty) => {
1183 let method_generics = &method_ty.generics;
1184 let method_bounds = &method_ty.predicates;
1185 cx.construct_parameter_environment(
1189 cx.region_maps.call_site_extent(id, body.id))
1193 .bug("ParameterEnvironment::for_item(): \
1194 got non-method item from impl method?!")
1200 Some(ast_map::NodeTraitItem(trait_item)) => {
1201 match trait_item.node {
1202 hir::TypeTraitItem(..) => {
1203 // associated types don't have their own entry (for some reason),
1204 // so for now just grab environment for the trait
1205 let trait_id = cx.map.get_parent(id);
1206 let trait_def_id = cx.map.local_def_id(trait_id);
1207 let trait_def = cx.lookup_trait_def(trait_def_id);
1208 let predicates = cx.lookup_predicates(trait_def_id);
1209 cx.construct_parameter_environment(trait_item.span,
1210 &trait_def.generics,
1212 cx.region_maps.item_extent(id))
1214 hir::ConstTraitItem(..) => {
1215 let def_id = cx.map.local_def_id(id);
1216 let scheme = cx.lookup_item_type(def_id);
1217 let predicates = cx.lookup_predicates(def_id);
1218 cx.construct_parameter_environment(trait_item.span,
1221 cx.region_maps.item_extent(id))
1223 hir::MethodTraitItem(_, ref body) => {
1224 // Use call-site for extent (unless this is a
1225 // trait method with no default; then fallback
1226 // to the method id).
1227 let method_def_id = cx.map.local_def_id(id);
1228 match cx.impl_or_trait_item(method_def_id) {
1229 MethodTraitItem(ref method_ty) => {
1230 let method_generics = &method_ty.generics;
1231 let method_bounds = &method_ty.predicates;
1232 let extent = if let Some(ref body) = *body {
1233 // default impl: use call_site extent as free_id_outlive bound.
1234 cx.region_maps.call_site_extent(id, body.id)
1236 // no default impl: use item extent as free_id_outlive bound.
1237 cx.region_maps.item_extent(id)
1239 cx.construct_parameter_environment(
1247 .bug("ParameterEnvironment::for_item(): \
1248 got non-method item from provided \
1255 Some(ast_map::NodeItem(item)) => {
1257 hir::ItemFn(_, _, _, _, _, ref body) => {
1258 // We assume this is a function.
1259 let fn_def_id = cx.map.local_def_id(id);
1260 let fn_scheme = cx.lookup_item_type(fn_def_id);
1261 let fn_predicates = cx.lookup_predicates(fn_def_id);
1263 cx.construct_parameter_environment(item.span,
1264 &fn_scheme.generics,
1266 cx.region_maps.call_site_extent(id,
1270 hir::ItemStruct(..) |
1272 hir::ItemConst(..) |
1273 hir::ItemStatic(..) => {
1274 let def_id = cx.map.local_def_id(id);
1275 let scheme = cx.lookup_item_type(def_id);
1276 let predicates = cx.lookup_predicates(def_id);
1277 cx.construct_parameter_environment(item.span,
1280 cx.region_maps.item_extent(id))
1282 hir::ItemTrait(..) => {
1283 let def_id = cx.map.local_def_id(id);
1284 let trait_def = cx.lookup_trait_def(def_id);
1285 let predicates = cx.lookup_predicates(def_id);
1286 cx.construct_parameter_environment(item.span,
1287 &trait_def.generics,
1289 cx.region_maps.item_extent(id))
1292 cx.sess.span_bug(item.span,
1293 "ParameterEnvironment::from_item():
1294 can't create a parameter \
1295 environment for this kind of item")
1299 Some(ast_map::NodeExpr(..)) => {
1300 // This is a convenience to allow closures to work.
1301 ParameterEnvironment::for_item(cx, cx.map.get_parent(id))
1304 cx.sess.bug(&format!("ParameterEnvironment::from_item(): \
1305 `{}` is not an item",
1306 cx.map.node_to_string(id)))
1312 /// A "type scheme", in ML terminology, is a type combined with some
1313 /// set of generic types that the type is, well, generic over. In Rust
1314 /// terms, it is the "type" of a fn item or struct -- this type will
1315 /// include various generic parameters that must be substituted when
1316 /// the item/struct is referenced. That is called converting the type
1317 /// scheme to a monotype.
1319 /// - `generics`: the set of type parameters and their bounds
1320 /// - `ty`: the base types, which may reference the parameters defined
1323 /// Note that TypeSchemes are also sometimes called "polytypes" (and
1324 /// in fact this struct used to carry that name, so you may find some
1325 /// stray references in a comment or something). We try to reserve the
1326 /// "poly" prefix to refer to higher-ranked things, as in
1329 /// Note that each item also comes with predicates, see
1330 /// `lookup_predicates`.
1331 #[derive(Clone, Debug)]
1332 pub struct TypeScheme<'tcx> {
1333 pub generics: Generics<'tcx>,
1338 flags AdtFlags: u32 {
1339 const NO_ADT_FLAGS = 0,
1340 const IS_ENUM = 1 << 0,
1341 const IS_DTORCK = 1 << 1, // is this a dtorck type?
1342 const IS_DTORCK_VALID = 1 << 2,
1343 const IS_PHANTOM_DATA = 1 << 3,
1344 const IS_SIMD = 1 << 4,
1345 const IS_FUNDAMENTAL = 1 << 5,
1346 const IS_NO_DROP_FLAG = 1 << 6,
1350 pub type AdtDef<'tcx> = &'tcx AdtDefData<'tcx, 'static>;
1351 pub type VariantDef<'tcx> = &'tcx VariantDefData<'tcx, 'static>;
1352 pub type FieldDef<'tcx> = &'tcx FieldDefData<'tcx, 'static>;
1354 // See comment on AdtDefData for explanation
1355 pub type AdtDefMaster<'tcx> = &'tcx AdtDefData<'tcx, 'tcx>;
1356 pub type VariantDefMaster<'tcx> = &'tcx VariantDefData<'tcx, 'tcx>;
1357 pub type FieldDefMaster<'tcx> = &'tcx FieldDefData<'tcx, 'tcx>;
1359 pub struct VariantDefData<'tcx, 'container: 'tcx> {
1360 /// The variant's DefId. If this is a tuple-like struct,
1361 /// this is the DefId of the struct's ctor.
1363 pub name: Name, // struct's name if this is a struct
1365 pub fields: Vec<FieldDefData<'tcx, 'container>>,
1366 pub kind: VariantKind,
1369 pub struct FieldDefData<'tcx, 'container: 'tcx> {
1370 /// The field's DefId. NOTE: the fields of tuple-like enum variants
1371 /// are not real items, and don't have entries in tcache etc.
1373 /// special_idents::unnamed_field.name
1374 /// if this is a tuple-like field
1376 pub vis: hir::Visibility,
1377 /// TyIVar is used here to allow for variance (see the doc at
1380 /// Note: direct accesses to `ty` must also add dep edges.
1381 ty: ivar::TyIVar<'tcx, 'container>
1384 /// The definition of an abstract data type - a struct or enum.
1386 /// These are all interned (by intern_adt_def) into the adt_defs
1389 /// Because of the possibility of nested tcx-s, this type
1390 /// needs 2 lifetimes: the traditional variant lifetime ('tcx)
1391 /// bounding the lifetime of the inner types is of course necessary.
1392 /// However, it is not sufficient - types from a child tcx must
1393 /// not be leaked into the master tcx by being stored in an AdtDefData.
1395 /// The 'container lifetime ensures that by outliving the container
1396 /// tcx and preventing shorter-lived types from being inserted. When
1397 /// write access is not needed, the 'container lifetime can be
1398 /// erased to 'static, which can be done by the AdtDef wrapper.
1399 pub struct AdtDefData<'tcx, 'container: 'tcx> {
1401 pub variants: Vec<VariantDefData<'tcx, 'container>>,
1402 destructor: Cell<Option<DefId>>,
1403 flags: Cell<AdtFlags>,
1406 impl<'tcx, 'container> PartialEq for AdtDefData<'tcx, 'container> {
1407 // AdtDefData are always interned and this is part of TyS equality
1409 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1412 impl<'tcx, 'container> Eq for AdtDefData<'tcx, 'container> {}
1414 impl<'tcx, 'container> Hash for AdtDefData<'tcx, 'container> {
1416 fn hash<H: Hasher>(&self, s: &mut H) {
1417 (self as *const AdtDefData).hash(s)
1421 impl<'tcx> Encodable for AdtDef<'tcx> {
1422 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1427 impl<'tcx> Decodable for AdtDef<'tcx> {
1428 fn decode<D: Decoder>(d: &mut D) -> Result<AdtDef<'tcx>, D::Error> {
1429 let def_id: DefId = try!{ Decodable::decode(d) };
1431 cstore::tls::with_decoding_context(d, |dcx, _| {
1432 let def_id = dcx.translate_def_id(def_id);
1433 Ok(dcx.tcx().lookup_adt_def(def_id))
1439 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1440 pub enum AdtKind { Struct, Enum }
1442 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1443 pub enum VariantKind { Struct, Tuple, Unit }
1446 pub fn from_variant_data(vdata: &hir::VariantData) -> Self {
1448 hir::VariantData::Struct(..) => VariantKind::Struct,
1449 hir::VariantData::Tuple(..) => VariantKind::Tuple,
1450 hir::VariantData::Unit(..) => VariantKind::Unit,
1455 impl<'tcx, 'container> AdtDefData<'tcx, 'container> {
1456 fn new(tcx: &ctxt<'tcx>,
1459 variants: Vec<VariantDefData<'tcx, 'container>>) -> Self {
1460 let mut flags = AdtFlags::NO_ADT_FLAGS;
1461 let attrs = tcx.get_attrs(did);
1462 if attr::contains_name(&attrs, "fundamental") {
1463 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1465 if attr::contains_name(&attrs, "unsafe_no_drop_flag") {
1466 flags = flags | AdtFlags::IS_NO_DROP_FLAG;
1468 if tcx.lookup_simd(did) {
1469 flags = flags | AdtFlags::IS_SIMD;
1471 if Some(did) == tcx.lang_items.phantom_data() {
1472 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1474 if let AdtKind::Enum = kind {
1475 flags = flags | AdtFlags::IS_ENUM;
1480 flags: Cell::new(flags),
1481 destructor: Cell::new(None)
1485 fn calculate_dtorck(&'tcx self, tcx: &ctxt<'tcx>) {
1486 if tcx.is_adt_dtorck(self) {
1487 self.flags.set(self.flags.get() | AdtFlags::IS_DTORCK);
1489 self.flags.set(self.flags.get() | AdtFlags::IS_DTORCK_VALID)
1492 /// Returns the kind of the ADT - Struct or Enum.
1494 pub fn adt_kind(&self) -> AdtKind {
1495 if self.flags.get().intersects(AdtFlags::IS_ENUM) {
1502 /// Returns whether this is a dtorck type. If this returns
1503 /// true, this type being safe for destruction requires it to be
1504 /// alive; Otherwise, only the contents are required to be.
1506 pub fn is_dtorck(&'tcx self, tcx: &ctxt<'tcx>) -> bool {
1507 if !self.flags.get().intersects(AdtFlags::IS_DTORCK_VALID) {
1508 self.calculate_dtorck(tcx)
1510 self.flags.get().intersects(AdtFlags::IS_DTORCK)
1513 /// Returns whether this type is #[fundamental] for the purposes
1514 /// of coherence checking.
1516 pub fn is_fundamental(&self) -> bool {
1517 self.flags.get().intersects(AdtFlags::IS_FUNDAMENTAL)
1521 pub fn is_simd(&self) -> bool {
1522 self.flags.get().intersects(AdtFlags::IS_SIMD)
1525 /// Returns true if this is PhantomData<T>.
1527 pub fn is_phantom_data(&self) -> bool {
1528 self.flags.get().intersects(AdtFlags::IS_PHANTOM_DATA)
1531 /// Returns whether this type has a destructor.
1532 pub fn has_dtor(&self) -> bool {
1533 match self.dtor_kind() {
1535 TraitDtor(..) => true
1539 /// Asserts this is a struct and returns the struct's unique
1541 pub fn struct_variant(&self) -> &VariantDefData<'tcx, 'container> {
1542 assert!(self.adt_kind() == AdtKind::Struct);
1547 pub fn type_scheme(&self, tcx: &ctxt<'tcx>) -> TypeScheme<'tcx> {
1548 tcx.lookup_item_type(self.did)
1552 pub fn predicates(&self, tcx: &ctxt<'tcx>) -> GenericPredicates<'tcx> {
1553 tcx.lookup_predicates(self.did)
1556 /// Returns an iterator over all fields contained
1559 pub fn all_fields(&self) ->
1561 slice::Iter<VariantDefData<'tcx, 'container>>,
1562 slice::Iter<FieldDefData<'tcx, 'container>>,
1563 for<'s> fn(&'s VariantDefData<'tcx, 'container>)
1564 -> slice::Iter<'s, FieldDefData<'tcx, 'container>>
1566 self.variants.iter().flat_map(VariantDefData::fields_iter)
1570 pub fn is_empty(&self) -> bool {
1571 self.variants.is_empty()
1575 pub fn is_univariant(&self) -> bool {
1576 self.variants.len() == 1
1579 pub fn is_payloadfree(&self) -> bool {
1580 !self.variants.is_empty() &&
1581 self.variants.iter().all(|v| v.fields.is_empty())
1584 pub fn variant_with_id(&self, vid: DefId) -> &VariantDefData<'tcx, 'container> {
1587 .find(|v| v.did == vid)
1588 .expect("variant_with_id: unknown variant")
1591 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1594 .position(|v| v.did == vid)
1595 .expect("variant_index_with_id: unknown variant")
1598 pub fn variant_of_def(&self, def: Def) -> &VariantDefData<'tcx, 'container> {
1600 Def::Variant(_, vid) => self.variant_with_id(vid),
1601 Def::Struct(..) | Def::TyAlias(..) => self.struct_variant(),
1602 _ => panic!("unexpected def {:?} in variant_of_def", def)
1606 pub fn destructor(&self) -> Option<DefId> {
1607 self.destructor.get()
1610 pub fn set_destructor(&self, dtor: DefId) {
1611 self.destructor.set(Some(dtor));
1614 pub fn dtor_kind(&self) -> DtorKind {
1615 match self.destructor.get() {
1617 TraitDtor(!self.flags.get().intersects(AdtFlags::IS_NO_DROP_FLAG))
1624 impl<'tcx, 'container> VariantDefData<'tcx, 'container> {
1626 fn fields_iter(&self) -> slice::Iter<FieldDefData<'tcx, 'container>> {
1630 pub fn kind(&self) -> VariantKind {
1634 pub fn is_tuple_struct(&self) -> bool {
1635 self.kind() == VariantKind::Tuple
1639 pub fn find_field_named(&self,
1641 -> Option<&FieldDefData<'tcx, 'container>> {
1642 self.fields.iter().find(|f| f.name == name)
1646 pub fn index_of_field_named(&self,
1649 self.fields.iter().position(|f| f.name == name)
1653 pub fn field_named(&self, name: ast::Name) -> &FieldDefData<'tcx, 'container> {
1654 self.find_field_named(name).unwrap()
1658 impl<'tcx, 'container> FieldDefData<'tcx, 'container> {
1659 pub fn new(did: DefId,
1661 vis: hir::Visibility) -> Self {
1666 ty: ivar::TyIVar::new()
1670 pub fn ty(&self, tcx: &ctxt<'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1671 self.unsubst_ty().subst(tcx, subst)
1674 pub fn unsubst_ty(&self) -> Ty<'tcx> {
1675 self.ty.unwrap(DepNode::FieldTy(self.did))
1678 pub fn fulfill_ty(&self, ty: Ty<'container>) {
1679 self.ty.fulfill(DepNode::FieldTy(self.did), ty);
1683 /// Records the substitutions used to translate the polytype for an
1684 /// item into the monotype of an item reference.
1686 pub struct ItemSubsts<'tcx> {
1687 pub substs: Substs<'tcx>,
1690 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Debug, RustcEncodable, RustcDecodable)]
1691 pub enum ClosureKind {
1692 // Warning: Ordering is significant here! The ordering is chosen
1693 // because the trait Fn is a subtrait of FnMut and so in turn, and
1694 // hence we order it so that Fn < FnMut < FnOnce.
1701 pub fn trait_did(&self, cx: &ctxt) -> DefId {
1702 let result = match *self {
1703 ClosureKind::Fn => cx.lang_items.require(FnTraitLangItem),
1704 ClosureKind::FnMut => {
1705 cx.lang_items.require(FnMutTraitLangItem)
1707 ClosureKind::FnOnce => {
1708 cx.lang_items.require(FnOnceTraitLangItem)
1712 Ok(trait_did) => trait_did,
1713 Err(err) => cx.sess.fatal(&err[..]),
1717 /// True if this a type that impls this closure kind
1718 /// must also implement `other`.
1719 pub fn extends(self, other: ty::ClosureKind) -> bool {
1720 match (self, other) {
1721 (ClosureKind::Fn, ClosureKind::Fn) => true,
1722 (ClosureKind::Fn, ClosureKind::FnMut) => true,
1723 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
1724 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
1725 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
1726 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
1732 impl<'tcx> TyS<'tcx> {
1733 /// Iterator that walks `self` and any types reachable from
1734 /// `self`, in depth-first order. Note that just walks the types
1735 /// that appear in `self`, it does not descend into the fields of
1736 /// structs or variants. For example:
1739 /// isize => { isize }
1740 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
1741 /// [isize] => { [isize], isize }
1743 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
1744 TypeWalker::new(self)
1747 /// Iterator that walks the immediate children of `self`. Hence
1748 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
1749 /// (but not `i32`, like `walk`).
1750 pub fn walk_shallow(&'tcx self) -> IntoIter<Ty<'tcx>> {
1751 walk::walk_shallow(self)
1754 /// Walks `ty` and any types appearing within `ty`, invoking the
1755 /// callback `f` on each type. If the callback returns false, then the
1756 /// children of the current type are ignored.
1758 /// Note: prefer `ty.walk()` where possible.
1759 pub fn maybe_walk<F>(&'tcx self, mut f: F)
1760 where F : FnMut(Ty<'tcx>) -> bool
1762 let mut walker = self.walk();
1763 while let Some(ty) = walker.next() {
1765 walker.skip_current_subtree();
1771 impl<'tcx> ItemSubsts<'tcx> {
1772 pub fn empty() -> ItemSubsts<'tcx> {
1773 ItemSubsts { substs: Substs::empty() }
1776 pub fn is_noop(&self) -> bool {
1777 self.substs.is_noop()
1781 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1782 pub enum LvaluePreference {
1787 impl LvaluePreference {
1788 pub fn from_mutbl(m: hir::Mutability) -> Self {
1790 hir::MutMutable => PreferMutLvalue,
1791 hir::MutImmutable => NoPreference,
1796 /// Helper for looking things up in the various maps that are populated during
1797 /// typeck::collect (e.g., `cx.impl_or_trait_items`, `cx.tcache`, etc). All of
1798 /// these share the pattern that if the id is local, it should have been loaded
1799 /// into the map by the `typeck::collect` phase. If the def-id is external,
1800 /// then we have to go consult the crate loading code (and cache the result for
1802 fn lookup_locally_or_in_crate_store<M, F>(descr: &str,
1807 M: MemoizationMap<Key=DefId>,
1808 F: FnOnce() -> M::Value,
1810 map.memoize(def_id, || {
1811 if def_id.is_local() {
1812 panic!("No def'n found for {:?} in tcx.{}", def_id, descr);
1819 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
1821 hir::MutMutable => MutBorrow,
1822 hir::MutImmutable => ImmBorrow,
1826 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
1827 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
1828 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
1830 pub fn to_mutbl_lossy(self) -> hir::Mutability {
1832 MutBorrow => hir::MutMutable,
1833 ImmBorrow => hir::MutImmutable,
1835 // We have no type corresponding to a unique imm borrow, so
1836 // use `&mut`. It gives all the capabilities of an `&uniq`
1837 // and hence is a safe "over approximation".
1838 UniqueImmBorrow => hir::MutMutable,
1842 pub fn to_user_str(&self) -> &'static str {
1844 MutBorrow => "mutable",
1845 ImmBorrow => "immutable",
1846 UniqueImmBorrow => "uniquely immutable",
1851 impl<'tcx> ctxt<'tcx> {
1852 pub fn node_id_to_type(&self, id: NodeId) -> Ty<'tcx> {
1853 match self.node_id_to_type_opt(id) {
1855 None => self.sess.bug(
1856 &format!("node_id_to_type: no type for node `{}`",
1857 self.map.node_to_string(id)))
1861 pub fn node_id_to_type_opt(&self, id: NodeId) -> Option<Ty<'tcx>> {
1862 self.tables.borrow().node_types.get(&id).cloned()
1865 pub fn node_id_item_substs(&self, id: NodeId) -> ItemSubsts<'tcx> {
1866 match self.tables.borrow().item_substs.get(&id) {
1867 None => ItemSubsts::empty(),
1868 Some(ts) => ts.clone(),
1872 // Returns the type of a pattern as a monotype. Like @expr_ty, this function
1873 // doesn't provide type parameter substitutions.
1874 pub fn pat_ty(&self, pat: &hir::Pat) -> Ty<'tcx> {
1875 self.node_id_to_type(pat.id)
1877 pub fn pat_ty_opt(&self, pat: &hir::Pat) -> Option<Ty<'tcx>> {
1878 self.node_id_to_type_opt(pat.id)
1881 // Returns the type of an expression as a monotype.
1883 // NB (1): This is the PRE-ADJUSTMENT TYPE for the expression. That is, in
1884 // some cases, we insert `AutoAdjustment` annotations such as auto-deref or
1885 // auto-ref. The type returned by this function does not consider such
1886 // adjustments. See `expr_ty_adjusted()` instead.
1888 // NB (2): This type doesn't provide type parameter substitutions; e.g. if you
1889 // ask for the type of "id" in "id(3)", it will return "fn(&isize) -> isize"
1890 // instead of "fn(ty) -> T with T = isize".
1891 pub fn expr_ty(&self, expr: &hir::Expr) -> Ty<'tcx> {
1892 self.node_id_to_type(expr.id)
1895 pub fn expr_ty_opt(&self, expr: &hir::Expr) -> Option<Ty<'tcx>> {
1896 self.node_id_to_type_opt(expr.id)
1899 /// Returns the type of `expr`, considering any `AutoAdjustment`
1900 /// entry recorded for that expression.
1902 /// It would almost certainly be better to store the adjusted ty in with
1903 /// the `AutoAdjustment`, but I opted not to do this because it would
1904 /// require serializing and deserializing the type and, although that's not
1905 /// hard to do, I just hate that code so much I didn't want to touch it
1906 /// unless it was to fix it properly, which seemed a distraction from the
1907 /// thread at hand! -nmatsakis
1908 pub fn expr_ty_adjusted(&self, expr: &hir::Expr) -> Ty<'tcx> {
1910 .adjust(self, expr.span, expr.id,
1911 self.tables.borrow().adjustments.get(&expr.id),
1913 self.tables.borrow().method_map.get(&method_call).map(|method| method.ty)
1917 pub fn expr_ty_adjusted_opt(&self, expr: &hir::Expr) -> Option<Ty<'tcx>> {
1918 self.expr_ty_opt(expr).map(|t| t.adjust(self,
1921 self.tables.borrow().adjustments.get(&expr.id),
1923 self.tables.borrow().method_map.get(&method_call).map(|method| method.ty)
1927 pub fn expr_span(&self, id: NodeId) -> Span {
1928 match self.map.find(id) {
1929 Some(ast_map::NodeExpr(e)) => {
1933 self.sess.bug(&format!("Node id {} is not an expr: {:?}",
1937 self.sess.bug(&format!("Node id {} is not present \
1938 in the node map", id));
1943 pub fn local_var_name_str(&self, id: NodeId) -> InternedString {
1944 match self.map.find(id) {
1945 Some(ast_map::NodeLocal(pat)) => {
1947 hir::PatIdent(_, ref path1, _) => path1.node.name.as_str(),
1949 self.sess.bug(&format!("Variable id {} maps to {:?}, not local", id, pat));
1953 r => self.sess.bug(&format!("Variable id {} maps to {:?}, not local", id, r)),
1957 pub fn resolve_expr(&self, expr: &hir::Expr) -> Def {
1958 match self.def_map.borrow().get(&expr.id) {
1959 Some(def) => def.full_def(),
1961 self.sess.span_bug(expr.span, &format!(
1962 "no def-map entry for expr {}", expr.id));
1967 pub fn expr_is_lval(&self, expr: &hir::Expr) -> bool {
1969 hir::ExprPath(..) => {
1970 // We can't use resolve_expr here, as this needs to run on broken
1971 // programs. We don't need to through - associated items are all
1973 match self.def_map.borrow().get(&expr.id) {
1974 Some(&def::PathResolution {
1975 base_def: Def::Static(..), ..
1976 }) | Some(&def::PathResolution {
1977 base_def: Def::Upvar(..), ..
1978 }) | Some(&def::PathResolution {
1979 base_def: Def::Local(..), ..
1983 Some(&def::PathResolution { base_def: Def::Err, .. })=> true,
1985 None => self.sess.span_bug(expr.span, &format!(
1986 "no def for path {}", expr.id))
1990 hir::ExprType(ref e, _) => {
1991 self.expr_is_lval(e)
1994 hir::ExprUnary(hir::UnDeref, _) |
1995 hir::ExprField(..) |
1996 hir::ExprTupField(..) |
1997 hir::ExprIndex(..) => {
2002 hir::ExprMethodCall(..) |
2003 hir::ExprStruct(..) |
2004 hir::ExprRange(..) |
2007 hir::ExprMatch(..) |
2008 hir::ExprClosure(..) |
2009 hir::ExprBlock(..) |
2010 hir::ExprRepeat(..) |
2012 hir::ExprBreak(..) |
2013 hir::ExprAgain(..) |
2015 hir::ExprWhile(..) |
2017 hir::ExprAssign(..) |
2018 hir::ExprInlineAsm(..) |
2019 hir::ExprAssignOp(..) |
2021 hir::ExprUnary(..) |
2023 hir::ExprAddrOf(..) |
2024 hir::ExprBinary(..) |
2025 hir::ExprCast(..) => {
2031 pub fn provided_trait_methods(&self, id: DefId) -> Vec<Rc<Method<'tcx>>> {
2032 if let Some(id) = self.map.as_local_node_id(id) {
2033 if let ItemTrait(_, _, _, ref ms) = self.map.expect_item(id).node {
2034 ms.iter().filter_map(|ti| {
2035 if let hir::MethodTraitItem(_, Some(_)) = ti.node {
2036 match self.impl_or_trait_item(self.map.local_def_id(ti.id)) {
2037 MethodTraitItem(m) => Some(m),
2039 self.sess.bug("provided_trait_methods(): \
2040 non-method item found from \
2041 looking up provided method?!")
2049 self.sess.bug(&format!("provided_trait_methods: `{:?}` is not a trait", id))
2052 self.sess.cstore.provided_trait_methods(self, id)
2056 pub fn associated_consts(&self, id: DefId) -> Vec<Rc<AssociatedConst<'tcx>>> {
2057 if let Some(id) = self.map.as_local_node_id(id) {
2058 match self.map.expect_item(id).node {
2059 ItemTrait(_, _, _, ref tis) => {
2060 tis.iter().filter_map(|ti| {
2061 if let hir::ConstTraitItem(_, _) = ti.node {
2062 match self.impl_or_trait_item(self.map.local_def_id(ti.id)) {
2063 ConstTraitItem(ac) => Some(ac),
2065 self.sess.bug("associated_consts(): \
2066 non-const item found from \
2067 looking up a constant?!")
2075 ItemImpl(_, _, _, _, _, ref iis) => {
2076 iis.iter().filter_map(|ii| {
2077 if let hir::ImplItemKind::Const(_, _) = ii.node {
2078 match self.impl_or_trait_item(self.map.local_def_id(ii.id)) {
2079 ConstTraitItem(ac) => Some(ac),
2081 self.sess.bug("associated_consts(): \
2082 non-const item found from \
2083 looking up a constant?!")
2092 self.sess.bug(&format!("associated_consts: `{:?}` is not a trait \
2097 self.sess.cstore.associated_consts(self, id)
2101 pub fn trait_impl_polarity(&self, id: DefId) -> Option<hir::ImplPolarity> {
2102 if let Some(id) = self.map.as_local_node_id(id) {
2103 match self.map.find(id) {
2104 Some(ast_map::NodeItem(item)) => {
2106 hir::ItemImpl(_, polarity, _, _, _, _) => Some(polarity),
2113 self.sess.cstore.impl_polarity(id)
2117 pub fn custom_coerce_unsized_kind(&self, did: DefId) -> adjustment::CustomCoerceUnsized {
2118 self.custom_coerce_unsized_kinds.memoize(did, || {
2119 let (kind, src) = if did.krate != LOCAL_CRATE {
2120 (self.sess.cstore.custom_coerce_unsized_kind(did), "external")
2128 self.sess.bug(&format!("custom_coerce_unsized_kind: \
2129 {} impl `{}` is missing its kind",
2130 src, self.item_path_str(did)));
2136 pub fn impl_or_trait_item(&self, id: DefId) -> ImplOrTraitItem<'tcx> {
2137 lookup_locally_or_in_crate_store(
2138 "impl_or_trait_items", id, &self.impl_or_trait_items,
2139 || self.sess.cstore.impl_or_trait_item(self, id))
2142 pub fn trait_item_def_ids(&self, id: DefId) -> Rc<Vec<ImplOrTraitItemId>> {
2143 lookup_locally_or_in_crate_store(
2144 "trait_item_def_ids", id, &self.trait_item_def_ids,
2145 || Rc::new(self.sess.cstore.trait_item_def_ids(id)))
2148 /// Returns the trait-ref corresponding to a given impl, or None if it is
2149 /// an inherent impl.
2150 pub fn impl_trait_ref(&self, id: DefId) -> Option<TraitRef<'tcx>> {
2151 lookup_locally_or_in_crate_store(
2152 "impl_trait_refs", id, &self.impl_trait_refs,
2153 || self.sess.cstore.impl_trait_ref(self, id))
2156 /// Returns whether this DefId refers to an impl
2157 pub fn is_impl(&self, id: DefId) -> bool {
2158 if let Some(id) = self.map.as_local_node_id(id) {
2159 if let Some(ast_map::NodeItem(
2160 &hir::Item { node: hir::ItemImpl(..), .. })) = self.map.find(id) {
2166 self.sess.cstore.is_impl(id)
2170 pub fn trait_ref_to_def_id(&self, tr: &hir::TraitRef) -> DefId {
2171 self.def_map.borrow().get(&tr.ref_id).expect("no def-map entry for trait").def_id()
2174 pub fn item_path_str(&self, id: DefId) -> String {
2175 self.with_path(id, |path| ast_map::path_to_string(path))
2178 pub fn def_path(&self, id: DefId) -> ast_map::DefPath {
2180 self.map.def_path(id)
2182 self.sess.cstore.def_path(id)
2186 pub fn with_path<T, F>(&self, id: DefId, f: F) -> T where
2187 F: FnOnce(ast_map::PathElems) -> T,
2189 if let Some(id) = self.map.as_local_node_id(id) {
2190 self.map.with_path(id, f)
2192 f(self.sess.cstore.item_path(id).iter().cloned().chain(LinkedPath::empty()))
2196 pub fn item_name(&self, id: DefId) -> ast::Name {
2197 if let Some(id) = self.map.as_local_node_id(id) {
2198 self.map.get_path_elem(id).name()
2200 self.sess.cstore.item_name(id)
2204 // Register a given item type
2205 pub fn register_item_type(&self, did: DefId, ty: TypeScheme<'tcx>) {
2206 self.tcache.borrow_mut().insert(did, ty);
2209 // If the given item is in an external crate, looks up its type and adds it to
2210 // the type cache. Returns the type parameters and type.
2211 pub fn lookup_item_type(&self, did: DefId) -> TypeScheme<'tcx> {
2212 lookup_locally_or_in_crate_store(
2213 "tcache", did, &self.tcache,
2214 || self.sess.cstore.item_type(self, did))
2217 /// Given the did of a trait, returns its canonical trait ref.
2218 pub fn lookup_trait_def(&self, did: DefId) -> &'tcx TraitDef<'tcx> {
2219 lookup_locally_or_in_crate_store(
2220 "trait_defs", did, &self.trait_defs,
2221 || self.alloc_trait_def(self.sess.cstore.trait_def(self, did))
2225 /// Given the did of an ADT, return a master reference to its
2226 /// definition. Unless you are planning on fulfilling the ADT's fields,
2227 /// use lookup_adt_def instead.
2228 pub fn lookup_adt_def_master(&self, did: DefId) -> AdtDefMaster<'tcx> {
2229 lookup_locally_or_in_crate_store(
2230 "adt_defs", did, &self.adt_defs,
2231 || self.sess.cstore.adt_def(self, did)
2235 /// Given the did of an ADT, return a reference to its definition.
2236 pub fn lookup_adt_def(&self, did: DefId) -> AdtDef<'tcx> {
2237 // when reverse-variance goes away, a transmute::<AdtDefMaster,AdtDef>
2238 // would be needed here.
2239 self.lookup_adt_def_master(did)
2242 /// Given the did of an item, returns its full set of predicates.
2243 pub fn lookup_predicates(&self, did: DefId) -> GenericPredicates<'tcx> {
2244 lookup_locally_or_in_crate_store(
2245 "predicates", did, &self.predicates,
2246 || self.sess.cstore.item_predicates(self, did))
2249 /// Given the did of a trait, returns its superpredicates.
2250 pub fn lookup_super_predicates(&self, did: DefId) -> GenericPredicates<'tcx> {
2251 lookup_locally_or_in_crate_store(
2252 "super_predicates", did, &self.super_predicates,
2253 || self.sess.cstore.item_super_predicates(self, did))
2256 /// If `type_needs_drop` returns true, then `ty` is definitely
2257 /// non-copy and *might* have a destructor attached; if it returns
2258 /// false, then `ty` definitely has no destructor (i.e. no drop glue).
2260 /// (Note that this implies that if `ty` has a destructor attached,
2261 /// then `type_needs_drop` will definitely return `true` for `ty`.)
2262 pub fn type_needs_drop_given_env<'a>(&self,
2264 param_env: &ty::ParameterEnvironment<'a,'tcx>) -> bool {
2265 // Issue #22536: We first query type_moves_by_default. It sees a
2266 // normalized version of the type, and therefore will definitely
2267 // know whether the type implements Copy (and thus needs no
2268 // cleanup/drop/zeroing) ...
2269 let implements_copy = !ty.moves_by_default(param_env, DUMMY_SP);
2271 if implements_copy { return false; }
2273 // ... (issue #22536 continued) but as an optimization, still use
2274 // prior logic of asking if the `needs_drop` bit is set; we need
2275 // not zero non-Copy types if they have no destructor.
2277 // FIXME(#22815): Note that calling `ty::type_contents` is a
2278 // conservative heuristic; it may report that `needs_drop` is set
2279 // when actual type does not actually have a destructor associated
2280 // with it. But since `ty` absolutely did not have the `Copy`
2281 // bound attached (see above), it is sound to treat it as having a
2282 // destructor (e.g. zero its memory on move).
2284 let contents = ty.type_contents(self);
2285 debug!("type_needs_drop ty={:?} contents={:?}", ty, contents);
2286 contents.needs_drop(self)
2289 /// Get the attributes of a definition.
2290 pub fn get_attrs(&self, did: DefId) -> Cow<'tcx, [ast::Attribute]> {
2291 if let Some(id) = self.map.as_local_node_id(did) {
2292 Cow::Borrowed(self.map.attrs(id))
2294 Cow::Owned(self.sess.cstore.item_attrs(did))
2298 /// Determine whether an item is annotated with an attribute
2299 pub fn has_attr(&self, did: DefId, attr: &str) -> bool {
2300 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2303 /// Determine whether an item is annotated with `#[repr(packed)]`
2304 pub fn lookup_packed(&self, did: DefId) -> bool {
2305 self.lookup_repr_hints(did).contains(&attr::ReprPacked)
2308 /// Determine whether an item is annotated with `#[simd]`
2309 pub fn lookup_simd(&self, did: DefId) -> bool {
2310 self.has_attr(did, "simd")
2311 || self.lookup_repr_hints(did).contains(&attr::ReprSimd)
2314 pub fn item_variances(&self, item_id: DefId) -> Rc<ItemVariances> {
2315 lookup_locally_or_in_crate_store(
2316 "item_variance_map", item_id, &self.item_variance_map,
2317 || Rc::new(self.sess.cstore.item_variances(item_id)))
2320 pub fn trait_has_default_impl(&self, trait_def_id: DefId) -> bool {
2321 self.populate_implementations_for_trait_if_necessary(trait_def_id);
2323 let def = self.lookup_trait_def(trait_def_id);
2324 def.flags.get().intersects(TraitFlags::HAS_DEFAULT_IMPL)
2327 /// Records a trait-to-implementation mapping.
2328 pub fn record_trait_has_default_impl(&self, trait_def_id: DefId) {
2329 let def = self.lookup_trait_def(trait_def_id);
2330 def.flags.set(def.flags.get() | TraitFlags::HAS_DEFAULT_IMPL)
2333 /// Load primitive inherent implementations if necessary
2334 pub fn populate_implementations_for_primitive_if_necessary(&self,
2335 primitive_def_id: DefId) {
2336 if primitive_def_id.is_local() {
2340 // The primitive is not local, hence we are reading this out
2342 let _ignore = self.dep_graph.in_ignore();
2344 if self.populated_external_primitive_impls.borrow().contains(&primitive_def_id) {
2348 debug!("populate_implementations_for_primitive_if_necessary: searching for {:?}",
2351 let impl_items = self.sess.cstore.impl_items(primitive_def_id);
2353 // Store the implementation info.
2354 self.impl_items.borrow_mut().insert(primitive_def_id, impl_items);
2355 self.populated_external_primitive_impls.borrow_mut().insert(primitive_def_id);
2358 /// Populates the type context with all the inherent implementations for
2359 /// the given type if necessary.
2360 pub fn populate_inherent_implementations_for_type_if_necessary(&self,
2362 if type_id.is_local() {
2366 // The type is not local, hence we are reading this out of
2367 // metadata and don't need to track edges.
2368 let _ignore = self.dep_graph.in_ignore();
2370 if self.populated_external_types.borrow().contains(&type_id) {
2374 debug!("populate_inherent_implementations_for_type_if_necessary: searching for {:?}",
2377 let inherent_impls = self.sess.cstore.inherent_implementations_for_type(type_id);
2378 for &impl_def_id in &inherent_impls {
2379 // Store the implementation info.
2380 let impl_items = self.sess.cstore.impl_items(impl_def_id);
2381 self.impl_items.borrow_mut().insert(impl_def_id, impl_items);
2384 self.inherent_impls.borrow_mut().insert(type_id, Rc::new(inherent_impls));
2385 self.populated_external_types.borrow_mut().insert(type_id);
2388 /// Populates the type context with all the implementations for the given
2389 /// trait if necessary.
2390 pub fn populate_implementations_for_trait_if_necessary(&self, trait_id: DefId) {
2391 if trait_id.is_local() {
2395 // The type is not local, hence we are reading this out of
2396 // metadata and don't need to track edges.
2397 let _ignore = self.dep_graph.in_ignore();
2399 let def = self.lookup_trait_def(trait_id);
2400 if def.flags.get().intersects(TraitFlags::IMPLS_VALID) {
2404 debug!("populate_implementations_for_trait_if_necessary: searching for {:?}", def);
2406 if self.sess.cstore.is_defaulted_trait(trait_id) {
2407 self.record_trait_has_default_impl(trait_id);
2410 for impl_def_id in self.sess.cstore.implementations_of_trait(trait_id) {
2411 let impl_items = self.sess.cstore.impl_items(impl_def_id);
2412 let trait_ref = self.impl_trait_ref(impl_def_id).unwrap();
2413 // Record the trait->implementation mapping.
2414 def.record_impl(self, impl_def_id, trait_ref);
2416 // For any methods that use a default implementation, add them to
2417 // the map. This is a bit unfortunate.
2418 for impl_item_def_id in &impl_items {
2419 let method_def_id = impl_item_def_id.def_id();
2420 // load impl items eagerly for convenience
2421 // FIXME: we may want to load these lazily
2422 self.impl_or_trait_item(method_def_id);
2425 // Store the implementation info.
2426 self.impl_items.borrow_mut().insert(impl_def_id, impl_items);
2429 def.flags.set(def.flags.get() | TraitFlags::IMPLS_VALID);
2432 pub fn closure_kind(&self, def_id: DefId) -> ty::ClosureKind {
2433 Tables::closure_kind(&self.tables, self, def_id)
2436 pub fn closure_type(&self,
2438 substs: &ClosureSubsts<'tcx>)
2439 -> ty::ClosureTy<'tcx>
2441 Tables::closure_type(&self.tables, self, def_id, substs)
2444 /// Given the def_id of an impl, return the def_id of the trait it implements.
2445 /// If it implements no trait, return `None`.
2446 pub fn trait_id_of_impl(&self, def_id: DefId) -> Option<DefId> {
2447 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2450 /// If the given def ID describes a method belonging to an impl, return the
2451 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2452 pub fn impl_of_method(&self, def_id: DefId) -> Option<DefId> {
2453 if def_id.krate != LOCAL_CRATE {
2454 return match self.sess.cstore.impl_or_trait_item(self, def_id).container() {
2455 TraitContainer(_) => None,
2456 ImplContainer(def_id) => Some(def_id),
2459 match self.impl_or_trait_items.borrow().get(&def_id).cloned() {
2460 Some(trait_item) => {
2461 match trait_item.container() {
2462 TraitContainer(_) => None,
2463 ImplContainer(def_id) => Some(def_id),
2470 /// If the given def ID describes an item belonging to a trait (either a
2471 /// default method or an implementation of a trait method), return the ID of
2472 /// the trait that the method belongs to. Otherwise, return `None`.
2473 pub fn trait_of_item(&self, def_id: DefId) -> Option<DefId> {
2474 if def_id.krate != LOCAL_CRATE {
2475 return self.sess.cstore.trait_of_item(self, def_id);
2477 match self.impl_or_trait_items.borrow().get(&def_id).cloned() {
2478 Some(impl_or_trait_item) => {
2479 match impl_or_trait_item.container() {
2480 TraitContainer(def_id) => Some(def_id),
2481 ImplContainer(def_id) => self.trait_id_of_impl(def_id),
2488 /// If the given def ID describes an item belonging to a trait, (either a
2489 /// default method or an implementation of a trait method), return the ID of
2490 /// the method inside trait definition (this means that if the given def ID
2491 /// is already that of the original trait method, then the return value is
2493 /// Otherwise, return `None`.
2494 pub fn trait_item_of_item(&self, def_id: DefId) -> Option<ImplOrTraitItemId> {
2495 let impl_item = match self.impl_or_trait_items.borrow().get(&def_id) {
2496 Some(m) => m.clone(),
2497 None => return None,
2499 let name = impl_item.name();
2500 match self.trait_of_item(def_id) {
2501 Some(trait_did) => {
2502 self.trait_items(trait_did).iter()
2503 .find(|item| item.name() == name)
2504 .map(|item| item.id())
2510 /// Construct a parameter environment suitable for static contexts or other contexts where there
2511 /// are no free type/lifetime parameters in scope.
2512 pub fn empty_parameter_environment<'a>(&'a self)
2513 -> ParameterEnvironment<'a,'tcx> {
2515 // for an empty parameter environment, there ARE no free
2516 // regions, so it shouldn't matter what we use for the free id
2517 let free_id_outlive = self.region_maps.node_extent(ast::DUMMY_NODE_ID);
2518 ty::ParameterEnvironment { tcx: self,
2519 free_substs: Substs::empty(),
2520 caller_bounds: Vec::new(),
2521 implicit_region_bound: ty::ReEmpty,
2522 selection_cache: traits::SelectionCache::new(),
2523 evaluation_cache: traits::EvaluationCache::new(),
2524 free_id_outlive: free_id_outlive }
2527 /// Constructs and returns a substitution that can be applied to move from
2528 /// the "outer" view of a type or method to the "inner" view.
2529 /// In general, this means converting from bound parameters to
2530 /// free parameters. Since we currently represent bound/free type
2531 /// parameters in the same way, this only has an effect on regions.
2532 pub fn construct_free_substs(&self, generics: &Generics<'tcx>,
2533 free_id_outlive: CodeExtent) -> Substs<'tcx> {
2535 let mut types = VecPerParamSpace::empty();
2536 for def in generics.types.as_slice() {
2537 debug!("construct_parameter_environment(): push_types_from_defs: def={:?}",
2539 types.push(def.space, self.mk_param_from_def(def));
2542 // map bound 'a => free 'a
2543 let mut regions = VecPerParamSpace::empty();
2544 for def in generics.regions.as_slice() {
2546 ReFree(FreeRegion { scope: free_id_outlive,
2547 bound_region: BrNamed(def.def_id, def.name) });
2548 debug!("push_region_params {:?}", region);
2549 regions.push(def.space, region);
2554 regions: subst::NonerasedRegions(regions)
2558 /// See `ParameterEnvironment` struct def'n for details.
2559 /// If you were using `free_id: NodeId`, you might try `self.region_maps.item_extent(free_id)`
2560 /// for the `free_id_outlive` parameter. (But note that that is not always quite right.)
2561 pub fn construct_parameter_environment<'a>(&'a self,
2563 generics: &ty::Generics<'tcx>,
2564 generic_predicates: &ty::GenericPredicates<'tcx>,
2565 free_id_outlive: CodeExtent)
2566 -> ParameterEnvironment<'a, 'tcx>
2569 // Construct the free substs.
2572 let free_substs = self.construct_free_substs(generics, free_id_outlive);
2575 // Compute the bounds on Self and the type parameters.
2578 let bounds = generic_predicates.instantiate(self, &free_substs);
2579 let bounds = self.liberate_late_bound_regions(free_id_outlive, &ty::Binder(bounds));
2580 let predicates = bounds.predicates.into_vec();
2582 // Finally, we have to normalize the bounds in the environment, in
2583 // case they contain any associated type projections. This process
2584 // can yield errors if the put in illegal associated types, like
2585 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2586 // report these errors right here; this doesn't actually feel
2587 // right to me, because constructing the environment feels like a
2588 // kind of a "idempotent" action, but I'm not sure where would be
2589 // a better place. In practice, we construct environments for
2590 // every fn once during type checking, and we'll abort if there
2591 // are any errors at that point, so after type checking you can be
2592 // sure that this will succeed without errors anyway.
2595 let unnormalized_env = ty::ParameterEnvironment {
2597 free_substs: free_substs,
2598 implicit_region_bound: ty::ReScope(free_id_outlive),
2599 caller_bounds: predicates,
2600 selection_cache: traits::SelectionCache::new(),
2601 evaluation_cache: traits::EvaluationCache::new(),
2602 free_id_outlive: free_id_outlive,
2605 let cause = traits::ObligationCause::misc(span, free_id_outlive.node_id(&self.region_maps));
2606 traits::normalize_param_env_or_error(unnormalized_env, cause)
2609 pub fn is_method_call(&self, expr_id: NodeId) -> bool {
2610 self.tables.borrow().method_map.contains_key(&MethodCall::expr(expr_id))
2613 pub fn is_overloaded_autoderef(&self, expr_id: NodeId, autoderefs: u32) -> bool {
2614 self.tables.borrow().method_map.contains_key(&MethodCall::autoderef(expr_id,
2618 pub fn upvar_capture(&self, upvar_id: ty::UpvarId) -> Option<ty::UpvarCapture> {
2619 Some(self.tables.borrow().upvar_capture_map.get(&upvar_id).unwrap().clone())
2623 pub fn visit_all_items_in_krate<V,F>(&self,
2626 where F: FnMut(DefId) -> DepNode, V: Visitor<'tcx>
2628 dep_graph::visit_all_items_in_krate(self, dep_node_fn, visitor);
2632 /// The category of explicit self.
2633 #[derive(Clone, Copy, Eq, PartialEq, Debug)]
2634 pub enum ExplicitSelfCategory {
2637 ByReference(Region, hir::Mutability),
2641 /// A free variable referred to in a function.
2642 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
2643 pub struct Freevar {
2644 /// The variable being accessed free.
2647 // First span where it is accessed (there can be multiple).
2651 pub type FreevarMap = NodeMap<Vec<Freevar>>;
2653 pub type CaptureModeMap = NodeMap<hir::CaptureClause>;
2655 // Trait method resolution
2656 pub type TraitMap = NodeMap<Vec<DefId>>;
2658 // Map from the NodeId of a glob import to a list of items which are actually
2660 pub type GlobMap = HashMap<NodeId, HashSet<Name>>;
2662 impl<'tcx> ctxt<'tcx> {
2663 pub fn with_freevars<T, F>(&self, fid: NodeId, f: F) -> T where
2664 F: FnOnce(&[Freevar]) -> T,
2666 match self.freevars.borrow().get(&fid) {
2668 Some(d) => f(&d[..])
2672 pub fn make_substs_for_receiver_types(&self,
2673 trait_ref: &ty::TraitRef<'tcx>,
2674 method: &ty::Method<'tcx>)
2675 -> subst::Substs<'tcx>
2678 * Substitutes the values for the receiver's type parameters
2679 * that are found in method, leaving the method's type parameters
2683 let meth_tps: Vec<Ty> =
2684 method.generics.types.get_slice(subst::FnSpace)
2686 .map(|def| self.mk_param_from_def(def))
2688 let meth_regions: Vec<ty::Region> =
2689 method.generics.regions.get_slice(subst::FnSpace)
2691 .map(|def| def.to_early_bound_region())
2693 trait_ref.substs.clone().with_method(meth_tps, meth_regions)