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::ImplOrTraitItemContainer::*;
16 pub use self::BorrowKind::*;
17 pub use self::ImplOrTraitItem::*;
18 pub use self::IntVarValue::*;
19 pub use self::LvaluePreference::*;
20 pub use self::fold::TypeFoldable;
22 use dep_graph::{self, DepNode};
23 use front::map as ast_map;
24 use front::map::LinkedPath;
26 use middle::cstore::{self, CrateStore, LOCAL_CRATE};
27 use middle::def::{self, Def, ExportMap};
28 use middle::def_id::DefId;
29 use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
30 use middle::region::{CodeExtent};
31 use middle::subst::{self, Subst, Substs, VecPerParamSpace};
34 use middle::ty::fold::TypeFolder;
35 use middle::ty::walk::TypeWalker;
36 use util::common::MemoizationMap;
37 use util::nodemap::{NodeMap, NodeSet};
38 use util::nodemap::FnvHashMap;
40 use serialize::{Encodable, Encoder, Decodable, Decoder};
41 use std::borrow::{Borrow, Cow};
43 use std::hash::{Hash, Hasher};
47 use std::vec::IntoIter;
48 use std::collections::{HashMap, HashSet};
49 use syntax::ast::{self, CrateNum, Name, NodeId};
50 use syntax::attr::{self, AttrMetaMethods};
51 use syntax::codemap::{DUMMY_SP, Span};
52 use syntax::parse::token::InternedString;
55 use rustc_front::hir::{ItemImpl, ItemTrait};
56 use rustc_front::intravisit::Visitor;
58 pub use self::sty::{Binder, DebruijnIndex};
59 pub use self::sty::{BuiltinBound, BuiltinBounds, ExistentialBounds};
60 pub use self::sty::{BareFnTy, FnSig, PolyFnSig, FnOutput, PolyFnOutput};
61 pub use self::sty::{ClosureTy, InferTy, ParamTy, ProjectionTy, TraitTy};
62 pub use self::sty::{ClosureSubsts, TypeAndMut};
63 pub use self::sty::{TraitRef, TypeVariants, PolyTraitRef};
64 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
65 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid, SkolemizedRegionVid};
66 pub use self::sty::BoundRegion::*;
67 pub use self::sty::FnOutput::*;
68 pub use self::sty::InferTy::*;
69 pub use self::sty::Region::*;
70 pub use self::sty::TypeVariants::*;
72 pub use self::sty::BuiltinBound::Send as BoundSend;
73 pub use self::sty::BuiltinBound::Sized as BoundSized;
74 pub use self::sty::BuiltinBound::Copy as BoundCopy;
75 pub use self::sty::BuiltinBound::Sync as BoundSync;
77 pub use self::contents::TypeContents;
78 pub use self::context::{ctxt, tls};
79 pub use self::context::{CtxtArenas, Lift, Tables};
81 pub use self::trait_def::{TraitDef, TraitFlags};
101 mod structural_impls;
105 pub const INITIAL_DISCRIMINANT_VALUE: Disr = 0;
109 /// The complete set of all analyses described in this module. This is
110 /// produced by the driver and fed to trans and later passes.
111 pub struct CrateAnalysis<'a> {
112 pub export_map: ExportMap,
113 pub access_levels: middle::privacy::AccessLevels,
114 pub reachable: NodeSet,
116 pub glob_map: Option<GlobMap>,
119 #[derive(Copy, Clone)]
126 pub fn is_present(&self) -> bool {
128 TraitDtor(..) => true,
133 pub fn has_drop_flag(&self) -> bool {
136 &TraitDtor(flag) => flag
141 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
142 pub enum ImplOrTraitItemContainer {
143 TraitContainer(DefId),
144 ImplContainer(DefId),
147 impl ImplOrTraitItemContainer {
148 pub fn id(&self) -> DefId {
150 TraitContainer(id) => id,
151 ImplContainer(id) => id,
157 pub enum ImplOrTraitItem<'tcx> {
158 ConstTraitItem(Rc<AssociatedConst<'tcx>>),
159 MethodTraitItem(Rc<Method<'tcx>>),
160 TypeTraitItem(Rc<AssociatedType<'tcx>>),
163 impl<'tcx> ImplOrTraitItem<'tcx> {
164 fn id(&self) -> ImplOrTraitItemId {
166 ConstTraitItem(ref associated_const) => {
167 ConstTraitItemId(associated_const.def_id)
169 MethodTraitItem(ref method) => MethodTraitItemId(method.def_id),
170 TypeTraitItem(ref associated_type) => {
171 TypeTraitItemId(associated_type.def_id)
176 pub fn def_id(&self) -> DefId {
178 ConstTraitItem(ref associated_const) => associated_const.def_id,
179 MethodTraitItem(ref method) => method.def_id,
180 TypeTraitItem(ref associated_type) => associated_type.def_id,
184 pub fn name(&self) -> Name {
186 ConstTraitItem(ref associated_const) => associated_const.name,
187 MethodTraitItem(ref method) => method.name,
188 TypeTraitItem(ref associated_type) => associated_type.name,
192 pub fn vis(&self) -> hir::Visibility {
194 ConstTraitItem(ref associated_const) => associated_const.vis,
195 MethodTraitItem(ref method) => method.vis,
196 TypeTraitItem(ref associated_type) => associated_type.vis,
200 pub fn container(&self) -> ImplOrTraitItemContainer {
202 ConstTraitItem(ref associated_const) => associated_const.container,
203 MethodTraitItem(ref method) => method.container,
204 TypeTraitItem(ref associated_type) => associated_type.container,
208 pub fn as_opt_method(&self) -> Option<Rc<Method<'tcx>>> {
210 MethodTraitItem(ref m) => Some((*m).clone()),
216 #[derive(Clone, Copy, Debug)]
217 pub enum ImplOrTraitItemId {
218 ConstTraitItemId(DefId),
219 MethodTraitItemId(DefId),
220 TypeTraitItemId(DefId),
223 impl ImplOrTraitItemId {
224 pub fn def_id(&self) -> DefId {
226 ConstTraitItemId(def_id) => def_id,
227 MethodTraitItemId(def_id) => def_id,
228 TypeTraitItemId(def_id) => def_id,
233 #[derive(Clone, Debug)]
234 pub struct Method<'tcx> {
236 pub generics: Generics<'tcx>,
237 pub predicates: GenericPredicates<'tcx>,
238 pub fty: BareFnTy<'tcx>,
239 pub explicit_self: ExplicitSelfCategory,
240 pub vis: hir::Visibility,
242 pub container: ImplOrTraitItemContainer,
245 impl<'tcx> Method<'tcx> {
246 pub fn new(name: Name,
247 generics: ty::Generics<'tcx>,
248 predicates: GenericPredicates<'tcx>,
250 explicit_self: ExplicitSelfCategory,
251 vis: hir::Visibility,
253 container: ImplOrTraitItemContainer)
258 predicates: predicates,
260 explicit_self: explicit_self,
263 container: container,
267 pub fn container_id(&self) -> DefId {
268 match self.container {
269 TraitContainer(id) => id,
270 ImplContainer(id) => id,
275 impl<'tcx> PartialEq for Method<'tcx> {
277 fn eq(&self, other: &Self) -> bool { self.def_id == other.def_id }
280 impl<'tcx> Eq for Method<'tcx> {}
282 impl<'tcx> Hash for Method<'tcx> {
284 fn hash<H: Hasher>(&self, s: &mut H) {
289 #[derive(Clone, Copy, Debug)]
290 pub struct AssociatedConst<'tcx> {
293 pub vis: hir::Visibility,
295 pub container: ImplOrTraitItemContainer,
299 #[derive(Clone, Copy, Debug)]
300 pub struct AssociatedType<'tcx> {
302 pub ty: Option<Ty<'tcx>>,
303 pub vis: hir::Visibility,
305 pub container: ImplOrTraitItemContainer,
308 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable)]
309 pub struct ItemVariances {
310 pub types: VecPerParamSpace<Variance>,
311 pub regions: VecPerParamSpace<Variance>,
314 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
316 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
317 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
318 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
319 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
322 #[derive(Clone, Copy, Debug)]
323 pub struct MethodCallee<'tcx> {
324 /// Impl method ID, for inherent methods, or trait method ID, otherwise.
327 pub substs: &'tcx subst::Substs<'tcx>
330 /// With method calls, we store some extra information in
331 /// side tables (i.e method_map). We use
332 /// MethodCall as a key to index into these tables instead of
333 /// just directly using the expression's NodeId. The reason
334 /// for this being that we may apply adjustments (coercions)
335 /// with the resulting expression also needing to use the
336 /// side tables. The problem with this is that we don't
337 /// assign a separate NodeId to this new expression
338 /// and so it would clash with the base expression if both
339 /// needed to add to the side tables. Thus to disambiguate
340 /// we also keep track of whether there's an adjustment in
342 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
343 pub struct MethodCall {
349 pub fn expr(id: NodeId) -> MethodCall {
356 pub fn autoderef(expr_id: NodeId, autoderef: u32) -> MethodCall {
359 autoderef: 1 + autoderef
364 // maps from an expression id that corresponds to a method call to the details
365 // of the method to be invoked
366 pub type MethodMap<'tcx> = FnvHashMap<MethodCall, MethodCallee<'tcx>>;
368 // Contains information needed to resolve types and (in the future) look up
369 // the types of AST nodes.
370 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
371 pub struct CReaderCacheKey {
376 /// A restriction that certain types must be the same size. The use of
377 /// `transmute` gives rise to these restrictions. These generally
378 /// cannot be checked until trans; therefore, each call to `transmute`
379 /// will push one or more such restriction into the
380 /// `transmute_restrictions` vector during `intrinsicck`. They are
381 /// then checked during `trans` by the fn `check_intrinsics`.
382 #[derive(Copy, Clone)]
383 pub struct TransmuteRestriction<'tcx> {
384 /// The span whence the restriction comes.
387 /// The type being transmuted from.
388 pub original_from: Ty<'tcx>,
390 /// The type being transmuted to.
391 pub original_to: Ty<'tcx>,
393 /// The type being transmuted from, with all type parameters
394 /// substituted for an arbitrary representative. Not to be shown
396 pub substituted_from: Ty<'tcx>,
398 /// The type being transmuted to, with all type parameters
399 /// substituted for an arbitrary representative. Not to be shown
401 pub substituted_to: Ty<'tcx>,
403 /// NodeId of the transmute intrinsic.
407 /// Describes the fragment-state associated with a NodeId.
409 /// Currently only unfragmented paths have entries in the table,
410 /// but longer-term this enum is expected to expand to also
411 /// include data for fragmented paths.
412 #[derive(Copy, Clone, Debug)]
413 pub enum FragmentInfo {
414 Moved { var: NodeId, move_expr: NodeId },
415 Assigned { var: NodeId, assign_expr: NodeId, assignee_id: NodeId },
418 // Flags that we track on types. These flags are propagated upwards
419 // through the type during type construction, so that we can quickly
420 // check whether the type has various kinds of types in it without
421 // recursing over the type itself.
423 flags TypeFlags: u32 {
424 const HAS_PARAMS = 1 << 0,
425 const HAS_SELF = 1 << 1,
426 const HAS_TY_INFER = 1 << 2,
427 const HAS_RE_INFER = 1 << 3,
428 const HAS_RE_EARLY_BOUND = 1 << 4,
429 const HAS_FREE_REGIONS = 1 << 5,
430 const HAS_TY_ERR = 1 << 6,
431 const HAS_PROJECTION = 1 << 7,
432 const HAS_TY_CLOSURE = 1 << 8,
434 // true if there are "names" of types and regions and so forth
435 // that are local to a particular fn
436 const HAS_LOCAL_NAMES = 1 << 9,
438 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
439 TypeFlags::HAS_SELF.bits |
440 TypeFlags::HAS_RE_EARLY_BOUND.bits,
442 // Flags representing the nominal content of a type,
443 // computed by FlagsComputation. If you add a new nominal
444 // flag, it should be added here too.
445 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
446 TypeFlags::HAS_SELF.bits |
447 TypeFlags::HAS_TY_INFER.bits |
448 TypeFlags::HAS_RE_INFER.bits |
449 TypeFlags::HAS_RE_EARLY_BOUND.bits |
450 TypeFlags::HAS_FREE_REGIONS.bits |
451 TypeFlags::HAS_TY_ERR.bits |
452 TypeFlags::HAS_PROJECTION.bits |
453 TypeFlags::HAS_TY_CLOSURE.bits |
454 TypeFlags::HAS_LOCAL_NAMES.bits,
456 // Caches for type_is_sized, type_moves_by_default
457 const SIZEDNESS_CACHED = 1 << 16,
458 const IS_SIZED = 1 << 17,
459 const MOVENESS_CACHED = 1 << 18,
460 const MOVES_BY_DEFAULT = 1 << 19,
464 pub struct TyS<'tcx> {
465 pub sty: TypeVariants<'tcx>,
466 pub flags: Cell<TypeFlags>,
468 // the maximal depth of any bound regions appearing in this type.
472 impl<'tcx> PartialEq for TyS<'tcx> {
474 fn eq(&self, other: &TyS<'tcx>) -> bool {
475 // (self as *const _) == (other as *const _)
476 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
479 impl<'tcx> Eq for TyS<'tcx> {}
481 impl<'tcx> Hash for TyS<'tcx> {
482 fn hash<H: Hasher>(&self, s: &mut H) {
483 (self as *const TyS).hash(s)
487 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
489 impl<'tcx> Encodable for Ty<'tcx> {
490 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
491 cstore::tls::with_encoding_context(s, |ecx, rbml_w| {
492 ecx.encode_ty(rbml_w, *self);
498 impl<'tcx> Decodable for Ty<'tcx> {
499 fn decode<D: Decoder>(d: &mut D) -> Result<Ty<'tcx>, D::Error> {
500 cstore::tls::with_decoding_context(d, |dcx, rbml_r| {
501 Ok(dcx.decode_ty(rbml_r))
507 /// Upvars do not get their own node-id. Instead, we use the pair of
508 /// the original var id (that is, the root variable that is referenced
509 /// by the upvar) and the id of the closure expression.
510 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
513 pub closure_expr_id: NodeId,
516 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
517 pub enum BorrowKind {
518 /// Data must be immutable and is aliasable.
521 /// Data must be immutable but not aliasable. This kind of borrow
522 /// cannot currently be expressed by the user and is used only in
523 /// implicit closure bindings. It is needed when you the closure
524 /// is borrowing or mutating a mutable referent, e.g.:
526 /// let x: &mut isize = ...;
527 /// let y = || *x += 5;
529 /// If we were to try to translate this closure into a more explicit
530 /// form, we'd encounter an error with the code as written:
532 /// struct Env { x: & &mut isize }
533 /// let x: &mut isize = ...;
534 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
535 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
537 /// This is then illegal because you cannot mutate a `&mut` found
538 /// in an aliasable location. To solve, you'd have to translate with
539 /// an `&mut` borrow:
541 /// struct Env { x: & &mut isize }
542 /// let x: &mut isize = ...;
543 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
544 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
546 /// Now the assignment to `**env.x` is legal, but creating a
547 /// mutable pointer to `x` is not because `x` is not mutable. We
548 /// could fix this by declaring `x` as `let mut x`. This is ok in
549 /// user code, if awkward, but extra weird for closures, since the
550 /// borrow is hidden.
552 /// So we introduce a "unique imm" borrow -- the referent is
553 /// immutable, but not aliasable. This solves the problem. For
554 /// simplicity, we don't give users the way to express this
555 /// borrow, it's just used when translating closures.
558 /// Data is mutable and not aliasable.
562 /// Information describing the capture of an upvar. This is computed
563 /// during `typeck`, specifically by `regionck`.
564 #[derive(PartialEq, Clone, Debug, Copy)]
565 pub enum UpvarCapture {
566 /// Upvar is captured by value. This is always true when the
567 /// closure is labeled `move`, but can also be true in other cases
568 /// depending on inference.
571 /// Upvar is captured by reference.
575 #[derive(PartialEq, Clone, Copy)]
576 pub struct UpvarBorrow {
577 /// The kind of borrow: by-ref upvars have access to shared
578 /// immutable borrows, which are not part of the normal language
580 pub kind: BorrowKind,
582 /// Region of the resulting reference.
583 pub region: ty::Region,
586 pub type UpvarCaptureMap = FnvHashMap<UpvarId, UpvarCapture>;
588 #[derive(Copy, Clone)]
589 pub struct ClosureUpvar<'tcx> {
595 #[derive(Clone, Copy, PartialEq)]
596 pub enum IntVarValue {
598 UintType(ast::UintTy),
601 /// Default region to use for the bound of objects that are
602 /// supplied as the value for this type parameter. This is derived
603 /// from `T:'a` annotations appearing in the type definition. If
604 /// this is `None`, then the default is inherited from the
605 /// surrounding context. See RFC #599 for details.
606 #[derive(Copy, Clone)]
607 pub enum ObjectLifetimeDefault {
608 /// Require an explicit annotation. Occurs when multiple
609 /// `T:'a` constraints are found.
612 /// Use the base default, typically 'static, but in a fn body it is a fresh variable
615 /// Use the given region as the default.
620 pub struct TypeParameterDef<'tcx> {
623 pub space: subst::ParamSpace,
625 pub default_def_id: DefId, // for use in error reporing about defaults
626 pub default: Option<Ty<'tcx>>,
627 pub object_lifetime_default: ObjectLifetimeDefault,
631 pub struct RegionParameterDef {
634 pub space: subst::ParamSpace,
636 pub bounds: Vec<ty::Region>,
639 impl RegionParameterDef {
640 pub fn to_early_bound_region(&self) -> ty::Region {
641 ty::ReEarlyBound(ty::EarlyBoundRegion {
647 pub fn to_bound_region(&self) -> ty::BoundRegion {
648 ty::BoundRegion::BrNamed(self.def_id, self.name)
652 /// Information about the formal type/lifetime parameters associated
653 /// with an item or method. Analogous to hir::Generics.
654 #[derive(Clone, Debug)]
655 pub struct Generics<'tcx> {
656 pub types: VecPerParamSpace<TypeParameterDef<'tcx>>,
657 pub regions: VecPerParamSpace<RegionParameterDef>,
660 impl<'tcx> Generics<'tcx> {
661 pub fn empty() -> Generics<'tcx> {
663 types: VecPerParamSpace::empty(),
664 regions: VecPerParamSpace::empty(),
668 pub fn is_empty(&self) -> bool {
669 self.types.is_empty() && self.regions.is_empty()
672 pub fn has_type_params(&self, space: subst::ParamSpace) -> bool {
673 !self.types.is_empty_in(space)
676 pub fn has_region_params(&self, space: subst::ParamSpace) -> bool {
677 !self.regions.is_empty_in(space)
681 /// Bounds on generics.
683 pub struct GenericPredicates<'tcx> {
684 pub predicates: VecPerParamSpace<Predicate<'tcx>>,
687 impl<'tcx> GenericPredicates<'tcx> {
688 pub fn empty() -> GenericPredicates<'tcx> {
690 predicates: VecPerParamSpace::empty(),
694 pub fn instantiate(&self, tcx: &ctxt<'tcx>, substs: &Substs<'tcx>)
695 -> InstantiatedPredicates<'tcx> {
696 InstantiatedPredicates {
697 predicates: self.predicates.subst(tcx, substs),
701 pub fn instantiate_supertrait(&self,
703 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
704 -> InstantiatedPredicates<'tcx>
706 InstantiatedPredicates {
707 predicates: self.predicates.map(|pred| pred.subst_supertrait(tcx, poly_trait_ref))
712 #[derive(Clone, PartialEq, Eq, Hash)]
713 pub enum Predicate<'tcx> {
714 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
715 /// the `Self` type of the trait reference and `A`, `B`, and `C`
716 /// would be the parameters in the `TypeSpace`.
717 Trait(PolyTraitPredicate<'tcx>),
719 /// where `T1 == T2`.
720 Equate(PolyEquatePredicate<'tcx>),
723 RegionOutlives(PolyRegionOutlivesPredicate),
726 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
728 /// where <T as TraitRef>::Name == X, approximately.
729 /// See `ProjectionPredicate` struct for details.
730 Projection(PolyProjectionPredicate<'tcx>),
733 WellFormed(Ty<'tcx>),
735 /// trait must be object-safe
739 impl<'tcx> Predicate<'tcx> {
740 /// Performs a substitution suitable for going from a
741 /// poly-trait-ref to supertraits that must hold if that
742 /// poly-trait-ref holds. This is slightly different from a normal
743 /// substitution in terms of what happens with bound regions. See
744 /// lengthy comment below for details.
745 pub fn subst_supertrait(&self,
747 trait_ref: &ty::PolyTraitRef<'tcx>)
748 -> ty::Predicate<'tcx>
750 // The interaction between HRTB and supertraits is not entirely
751 // obvious. Let me walk you (and myself) through an example.
753 // Let's start with an easy case. Consider two traits:
755 // trait Foo<'a> : Bar<'a,'a> { }
756 // trait Bar<'b,'c> { }
758 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
759 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
760 // knew that `Foo<'x>` (for any 'x) then we also know that
761 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
762 // normal substitution.
764 // In terms of why this is sound, the idea is that whenever there
765 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
766 // holds. So if there is an impl of `T:Foo<'a>` that applies to
767 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
770 // Another example to be careful of is this:
772 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
773 // trait Bar1<'b,'c> { }
775 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
776 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
777 // reason is similar to the previous example: any impl of
778 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
779 // basically we would want to collapse the bound lifetimes from
780 // the input (`trait_ref`) and the supertraits.
782 // To achieve this in practice is fairly straightforward. Let's
783 // consider the more complicated scenario:
785 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
786 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
787 // where both `'x` and `'b` would have a DB index of 1.
788 // The substitution from the input trait-ref is therefore going to be
789 // `'a => 'x` (where `'x` has a DB index of 1).
790 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
791 // early-bound parameter and `'b' is a late-bound parameter with a
793 // - If we replace `'a` with `'x` from the input, it too will have
794 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
795 // just as we wanted.
797 // There is only one catch. If we just apply the substitution `'a
798 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
799 // adjust the DB index because we substituting into a binder (it
800 // tries to be so smart...) resulting in `for<'x> for<'b>
801 // Bar1<'x,'b>` (we have no syntax for this, so use your
802 // imagination). Basically the 'x will have DB index of 2 and 'b
803 // will have DB index of 1. Not quite what we want. So we apply
804 // the substitution to the *contents* of the trait reference,
805 // rather than the trait reference itself (put another way, the
806 // substitution code expects equal binding levels in the values
807 // from the substitution and the value being substituted into, and
808 // this trick achieves that).
810 let substs = &trait_ref.0.substs;
812 Predicate::Trait(ty::Binder(ref data)) =>
813 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
814 Predicate::Equate(ty::Binder(ref data)) =>
815 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
816 Predicate::RegionOutlives(ty::Binder(ref data)) =>
817 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
818 Predicate::TypeOutlives(ty::Binder(ref data)) =>
819 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
820 Predicate::Projection(ty::Binder(ref data)) =>
821 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
822 Predicate::WellFormed(data) =>
823 Predicate::WellFormed(data.subst(tcx, substs)),
824 Predicate::ObjectSafe(trait_def_id) =>
825 Predicate::ObjectSafe(trait_def_id),
830 #[derive(Clone, PartialEq, Eq, Hash)]
831 pub struct TraitPredicate<'tcx> {
832 pub trait_ref: TraitRef<'tcx>
834 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
836 impl<'tcx> TraitPredicate<'tcx> {
837 pub fn def_id(&self) -> DefId {
838 self.trait_ref.def_id
841 /// Creates the dep-node for selecting/evaluating this trait reference.
842 fn dep_node(&self) -> DepNode {
843 DepNode::TraitSelect(self.def_id())
846 pub fn input_types(&self) -> &[Ty<'tcx>] {
847 self.trait_ref.substs.types.as_slice()
850 pub fn self_ty(&self) -> Ty<'tcx> {
851 self.trait_ref.self_ty()
855 impl<'tcx> PolyTraitPredicate<'tcx> {
856 pub fn def_id(&self) -> DefId {
857 // ok to skip binder since trait def-id does not care about regions
861 pub fn dep_node(&self) -> DepNode {
862 // ok to skip binder since depnode does not care about regions
867 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
868 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
869 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
871 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
872 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
873 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
874 pub type PolyRegionOutlivesPredicate = PolyOutlivesPredicate<ty::Region, ty::Region>;
875 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region>;
877 /// This kind of predicate has no *direct* correspondent in the
878 /// syntax, but it roughly corresponds to the syntactic forms:
880 /// 1. `T : TraitRef<..., Item=Type>`
881 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
883 /// In particular, form #1 is "desugared" to the combination of a
884 /// normal trait predicate (`T : TraitRef<...>`) and one of these
885 /// predicates. Form #2 is a broader form in that it also permits
886 /// equality between arbitrary types. Processing an instance of Form
887 /// #2 eventually yields one of these `ProjectionPredicate`
888 /// instances to normalize the LHS.
889 #[derive(Clone, PartialEq, Eq, Hash)]
890 pub struct ProjectionPredicate<'tcx> {
891 pub projection_ty: ProjectionTy<'tcx>,
895 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
897 impl<'tcx> PolyProjectionPredicate<'tcx> {
898 pub fn item_name(&self) -> Name {
899 self.0.projection_ty.item_name // safe to skip the binder to access a name
902 pub fn sort_key(&self) -> (DefId, Name) {
903 self.0.projection_ty.sort_key()
907 pub trait ToPolyTraitRef<'tcx> {
908 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
911 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
912 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
913 assert!(!self.has_escaping_regions());
914 ty::Binder(self.clone())
918 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
919 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
920 self.map_bound_ref(|trait_pred| trait_pred.trait_ref.clone())
924 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
925 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
926 // Note: unlike with TraitRef::to_poly_trait_ref(),
927 // self.0.trait_ref is permitted to have escaping regions.
928 // This is because here `self` has a `Binder` and so does our
929 // return value, so we are preserving the number of binding
931 ty::Binder(self.0.projection_ty.trait_ref.clone())
935 pub trait ToPredicate<'tcx> {
936 fn to_predicate(&self) -> Predicate<'tcx>;
939 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
940 fn to_predicate(&self) -> Predicate<'tcx> {
941 // we're about to add a binder, so let's check that we don't
942 // accidentally capture anything, or else that might be some
943 // weird debruijn accounting.
944 assert!(!self.has_escaping_regions());
946 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
947 trait_ref: self.clone()
952 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
953 fn to_predicate(&self) -> Predicate<'tcx> {
954 ty::Predicate::Trait(self.to_poly_trait_predicate())
958 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
959 fn to_predicate(&self) -> Predicate<'tcx> {
960 Predicate::Equate(self.clone())
964 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate {
965 fn to_predicate(&self) -> Predicate<'tcx> {
966 Predicate::RegionOutlives(self.clone())
970 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
971 fn to_predicate(&self) -> Predicate<'tcx> {
972 Predicate::TypeOutlives(self.clone())
976 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
977 fn to_predicate(&self) -> Predicate<'tcx> {
978 Predicate::Projection(self.clone())
982 impl<'tcx> Predicate<'tcx> {
983 /// Iterates over the types in this predicate. Note that in all
984 /// cases this is skipping over a binder, so late-bound regions
985 /// with depth 0 are bound by the predicate.
986 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
987 let vec: Vec<_> = match *self {
988 ty::Predicate::Trait(ref data) => {
989 data.0.trait_ref.substs.types.as_slice().to_vec()
991 ty::Predicate::Equate(ty::Binder(ref data)) => {
994 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
997 ty::Predicate::RegionOutlives(..) => {
1000 ty::Predicate::Projection(ref data) => {
1001 let trait_inputs = data.0.projection_ty.trait_ref.substs.types.as_slice();
1004 .chain(Some(data.0.ty))
1007 ty::Predicate::WellFormed(data) => {
1010 ty::Predicate::ObjectSafe(_trait_def_id) => {
1015 // The only reason to collect into a vector here is that I was
1016 // too lazy to make the full (somewhat complicated) iterator
1017 // type that would be needed here. But I wanted this fn to
1018 // return an iterator conceptually, rather than a `Vec`, so as
1019 // to be closer to `Ty::walk`.
1023 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1025 Predicate::Trait(ref t) => {
1026 Some(t.to_poly_trait_ref())
1028 Predicate::Projection(..) |
1029 Predicate::Equate(..) |
1030 Predicate::RegionOutlives(..) |
1031 Predicate::WellFormed(..) |
1032 Predicate::ObjectSafe(..) |
1033 Predicate::TypeOutlives(..) => {
1040 /// Represents the bounds declared on a particular set of type
1041 /// parameters. Should eventually be generalized into a flag list of
1042 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1043 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1044 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1045 /// the `GenericPredicates` are expressed in terms of the bound type
1046 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1047 /// represented a set of bounds for some particular instantiation,
1048 /// meaning that the generic parameters have been substituted with
1053 /// struct Foo<T,U:Bar<T>> { ... }
1055 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1056 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1057 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1058 /// [usize:Bar<isize>]]`.
1060 pub struct InstantiatedPredicates<'tcx> {
1061 pub predicates: VecPerParamSpace<Predicate<'tcx>>,
1064 impl<'tcx> InstantiatedPredicates<'tcx> {
1065 pub fn empty() -> InstantiatedPredicates<'tcx> {
1066 InstantiatedPredicates { predicates: VecPerParamSpace::empty() }
1069 pub fn is_empty(&self) -> bool {
1070 self.predicates.is_empty()
1074 impl<'tcx> TraitRef<'tcx> {
1075 pub fn new(def_id: DefId, substs: &'tcx Substs<'tcx>) -> TraitRef<'tcx> {
1076 TraitRef { def_id: def_id, substs: substs }
1079 pub fn self_ty(&self) -> Ty<'tcx> {
1080 self.substs.self_ty().unwrap()
1083 pub fn input_types(&self) -> &[Ty<'tcx>] {
1084 // Select only the "input types" from a trait-reference. For
1085 // now this is all the types that appear in the
1086 // trait-reference, but it should eventually exclude
1087 // associated types.
1088 self.substs.types.as_slice()
1092 /// When type checking, we use the `ParameterEnvironment` to track
1093 /// details about the type/lifetime parameters that are in scope.
1094 /// It primarily stores the bounds information.
1096 /// Note: This information might seem to be redundant with the data in
1097 /// `tcx.ty_param_defs`, but it is not. That table contains the
1098 /// parameter definitions from an "outside" perspective, but this
1099 /// struct will contain the bounds for a parameter as seen from inside
1100 /// the function body. Currently the only real distinction is that
1101 /// bound lifetime parameters are replaced with free ones, but in the
1102 /// future I hope to refine the representation of types so as to make
1103 /// more distinctions clearer.
1105 pub struct ParameterEnvironment<'a, 'tcx:'a> {
1106 pub tcx: &'a ctxt<'tcx>,
1108 /// See `construct_free_substs` for details.
1109 pub free_substs: Substs<'tcx>,
1111 /// Each type parameter has an implicit region bound that
1112 /// indicates it must outlive at least the function body (the user
1113 /// may specify stronger requirements). This field indicates the
1114 /// region of the callee.
1115 pub implicit_region_bound: ty::Region,
1117 /// Obligations that the caller must satisfy. This is basically
1118 /// the set of bounds on the in-scope type parameters, translated
1119 /// into Obligations, and elaborated and normalized.
1120 pub caller_bounds: Vec<ty::Predicate<'tcx>>,
1122 /// Caches the results of trait selection. This cache is used
1123 /// for things that have to do with the parameters in scope.
1124 pub selection_cache: traits::SelectionCache<'tcx>,
1126 /// Caches the results of trait evaluation.
1127 pub evaluation_cache: traits::EvaluationCache<'tcx>,
1129 /// Scope that is attached to free regions for this scope. This
1130 /// is usually the id of the fn body, but for more abstract scopes
1131 /// like structs we often use the node-id of the struct.
1133 /// FIXME(#3696). It would be nice to refactor so that free
1134 /// regions don't have this implicit scope and instead introduce
1135 /// relationships in the environment.
1136 pub free_id_outlive: CodeExtent,
1139 impl<'a, 'tcx> ParameterEnvironment<'a, 'tcx> {
1140 pub fn with_caller_bounds(&self,
1141 caller_bounds: Vec<ty::Predicate<'tcx>>)
1142 -> ParameterEnvironment<'a,'tcx>
1144 ParameterEnvironment {
1146 free_substs: self.free_substs.clone(),
1147 implicit_region_bound: self.implicit_region_bound,
1148 caller_bounds: caller_bounds,
1149 selection_cache: traits::SelectionCache::new(),
1150 evaluation_cache: traits::EvaluationCache::new(),
1151 free_id_outlive: self.free_id_outlive,
1155 pub fn for_item(cx: &'a ctxt<'tcx>, id: NodeId) -> ParameterEnvironment<'a, 'tcx> {
1156 match cx.map.find(id) {
1157 Some(ast_map::NodeImplItem(ref impl_item)) => {
1158 match impl_item.node {
1159 hir::ImplItemKind::Type(_) => {
1160 // associated types don't have their own entry (for some reason),
1161 // so for now just grab environment for the impl
1162 let impl_id = cx.map.get_parent(id);
1163 let impl_def_id = cx.map.local_def_id(impl_id);
1164 let scheme = cx.lookup_item_type(impl_def_id);
1165 let predicates = cx.lookup_predicates(impl_def_id);
1166 cx.construct_parameter_environment(impl_item.span,
1169 cx.region_maps.item_extent(id))
1171 hir::ImplItemKind::Const(_, _) => {
1172 let def_id = cx.map.local_def_id(id);
1173 let scheme = cx.lookup_item_type(def_id);
1174 let predicates = cx.lookup_predicates(def_id);
1175 cx.construct_parameter_environment(impl_item.span,
1178 cx.region_maps.item_extent(id))
1180 hir::ImplItemKind::Method(_, ref body) => {
1181 let method_def_id = cx.map.local_def_id(id);
1182 match cx.impl_or_trait_item(method_def_id) {
1183 MethodTraitItem(ref method_ty) => {
1184 let method_generics = &method_ty.generics;
1185 let method_bounds = &method_ty.predicates;
1186 cx.construct_parameter_environment(
1190 cx.region_maps.call_site_extent(id, body.id))
1194 .bug("ParameterEnvironment::for_item(): \
1195 got non-method item from impl method?!")
1201 Some(ast_map::NodeTraitItem(trait_item)) => {
1202 match trait_item.node {
1203 hir::TypeTraitItem(..) => {
1204 // associated types don't have their own entry (for some reason),
1205 // so for now just grab environment for the trait
1206 let trait_id = cx.map.get_parent(id);
1207 let trait_def_id = cx.map.local_def_id(trait_id);
1208 let trait_def = cx.lookup_trait_def(trait_def_id);
1209 let predicates = cx.lookup_predicates(trait_def_id);
1210 cx.construct_parameter_environment(trait_item.span,
1211 &trait_def.generics,
1213 cx.region_maps.item_extent(id))
1215 hir::ConstTraitItem(..) => {
1216 let def_id = cx.map.local_def_id(id);
1217 let scheme = cx.lookup_item_type(def_id);
1218 let predicates = cx.lookup_predicates(def_id);
1219 cx.construct_parameter_environment(trait_item.span,
1222 cx.region_maps.item_extent(id))
1224 hir::MethodTraitItem(_, ref body) => {
1225 // Use call-site for extent (unless this is a
1226 // trait method with no default; then fallback
1227 // to the method id).
1228 let method_def_id = cx.map.local_def_id(id);
1229 match cx.impl_or_trait_item(method_def_id) {
1230 MethodTraitItem(ref method_ty) => {
1231 let method_generics = &method_ty.generics;
1232 let method_bounds = &method_ty.predicates;
1233 let extent = if let Some(ref body) = *body {
1234 // default impl: use call_site extent as free_id_outlive bound.
1235 cx.region_maps.call_site_extent(id, body.id)
1237 // no default impl: use item extent as free_id_outlive bound.
1238 cx.region_maps.item_extent(id)
1240 cx.construct_parameter_environment(
1248 .bug("ParameterEnvironment::for_item(): \
1249 got non-method item from provided \
1256 Some(ast_map::NodeItem(item)) => {
1258 hir::ItemFn(_, _, _, _, _, ref body) => {
1259 // We assume this is a function.
1260 let fn_def_id = cx.map.local_def_id(id);
1261 let fn_scheme = cx.lookup_item_type(fn_def_id);
1262 let fn_predicates = cx.lookup_predicates(fn_def_id);
1264 cx.construct_parameter_environment(item.span,
1265 &fn_scheme.generics,
1267 cx.region_maps.call_site_extent(id,
1271 hir::ItemStruct(..) |
1273 hir::ItemConst(..) |
1274 hir::ItemStatic(..) => {
1275 let def_id = cx.map.local_def_id(id);
1276 let scheme = cx.lookup_item_type(def_id);
1277 let predicates = cx.lookup_predicates(def_id);
1278 cx.construct_parameter_environment(item.span,
1281 cx.region_maps.item_extent(id))
1283 hir::ItemTrait(..) => {
1284 let def_id = cx.map.local_def_id(id);
1285 let trait_def = cx.lookup_trait_def(def_id);
1286 let predicates = cx.lookup_predicates(def_id);
1287 cx.construct_parameter_environment(item.span,
1288 &trait_def.generics,
1290 cx.region_maps.item_extent(id))
1293 cx.sess.span_bug(item.span,
1294 "ParameterEnvironment::from_item():
1295 can't create a parameter \
1296 environment for this kind of item")
1300 Some(ast_map::NodeExpr(..)) => {
1301 // This is a convenience to allow closures to work.
1302 ParameterEnvironment::for_item(cx, cx.map.get_parent(id))
1305 cx.sess.bug(&format!("ParameterEnvironment::from_item(): \
1306 `{}` is not an item",
1307 cx.map.node_to_string(id)))
1313 /// A "type scheme", in ML terminology, is a type combined with some
1314 /// set of generic types that the type is, well, generic over. In Rust
1315 /// terms, it is the "type" of a fn item or struct -- this type will
1316 /// include various generic parameters that must be substituted when
1317 /// the item/struct is referenced. That is called converting the type
1318 /// scheme to a monotype.
1320 /// - `generics`: the set of type parameters and their bounds
1321 /// - `ty`: the base types, which may reference the parameters defined
1324 /// Note that TypeSchemes are also sometimes called "polytypes" (and
1325 /// in fact this struct used to carry that name, so you may find some
1326 /// stray references in a comment or something). We try to reserve the
1327 /// "poly" prefix to refer to higher-ranked things, as in
1330 /// Note that each item also comes with predicates, see
1331 /// `lookup_predicates`.
1332 #[derive(Clone, Debug)]
1333 pub struct TypeScheme<'tcx> {
1334 pub generics: Generics<'tcx>,
1339 flags AdtFlags: u32 {
1340 const NO_ADT_FLAGS = 0,
1341 const IS_ENUM = 1 << 0,
1342 const IS_DTORCK = 1 << 1, // is this a dtorck type?
1343 const IS_DTORCK_VALID = 1 << 2,
1344 const IS_PHANTOM_DATA = 1 << 3,
1345 const IS_SIMD = 1 << 4,
1346 const IS_FUNDAMENTAL = 1 << 5,
1347 const IS_NO_DROP_FLAG = 1 << 6,
1351 pub type AdtDef<'tcx> = &'tcx AdtDefData<'tcx, 'static>;
1352 pub type VariantDef<'tcx> = &'tcx VariantDefData<'tcx, 'static>;
1353 pub type FieldDef<'tcx> = &'tcx FieldDefData<'tcx, 'static>;
1355 // See comment on AdtDefData for explanation
1356 pub type AdtDefMaster<'tcx> = &'tcx AdtDefData<'tcx, 'tcx>;
1357 pub type VariantDefMaster<'tcx> = &'tcx VariantDefData<'tcx, 'tcx>;
1358 pub type FieldDefMaster<'tcx> = &'tcx FieldDefData<'tcx, 'tcx>;
1360 pub struct VariantDefData<'tcx, 'container: 'tcx> {
1361 /// The variant's DefId. If this is a tuple-like struct,
1362 /// this is the DefId of the struct's ctor.
1364 pub name: Name, // struct's name if this is a struct
1366 pub fields: Vec<FieldDefData<'tcx, 'container>>,
1367 pub kind: VariantKind,
1370 pub struct FieldDefData<'tcx, 'container: 'tcx> {
1371 /// The field's DefId. NOTE: the fields of tuple-like enum variants
1372 /// are not real items, and don't have entries in tcache etc.
1374 /// special_idents::unnamed_field.name
1375 /// if this is a tuple-like field
1377 pub vis: hir::Visibility,
1378 /// TyIVar is used here to allow for variance (see the doc at
1381 /// Note: direct accesses to `ty` must also add dep edges.
1382 ty: ivar::TyIVar<'tcx, 'container>
1385 /// The definition of an abstract data type - a struct or enum.
1387 /// These are all interned (by intern_adt_def) into the adt_defs
1390 /// Because of the possibility of nested tcx-s, this type
1391 /// needs 2 lifetimes: the traditional variant lifetime ('tcx)
1392 /// bounding the lifetime of the inner types is of course necessary.
1393 /// However, it is not sufficient - types from a child tcx must
1394 /// not be leaked into the master tcx by being stored in an AdtDefData.
1396 /// The 'container lifetime ensures that by outliving the container
1397 /// tcx and preventing shorter-lived types from being inserted. When
1398 /// write access is not needed, the 'container lifetime can be
1399 /// erased to 'static, which can be done by the AdtDef wrapper.
1400 pub struct AdtDefData<'tcx, 'container: 'tcx> {
1402 pub variants: Vec<VariantDefData<'tcx, 'container>>,
1403 destructor: Cell<Option<DefId>>,
1404 flags: Cell<AdtFlags>,
1407 impl<'tcx, 'container> PartialEq for AdtDefData<'tcx, 'container> {
1408 // AdtDefData are always interned and this is part of TyS equality
1410 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1413 impl<'tcx, 'container> Eq for AdtDefData<'tcx, 'container> {}
1415 impl<'tcx, 'container> Hash for AdtDefData<'tcx, 'container> {
1417 fn hash<H: Hasher>(&self, s: &mut H) {
1418 (self as *const AdtDefData).hash(s)
1422 impl<'tcx> Encodable for AdtDef<'tcx> {
1423 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1428 impl<'tcx> Decodable for AdtDef<'tcx> {
1429 fn decode<D: Decoder>(d: &mut D) -> Result<AdtDef<'tcx>, D::Error> {
1430 let def_id: DefId = try!{ Decodable::decode(d) };
1432 cstore::tls::with_decoding_context(d, |dcx, _| {
1433 let def_id = dcx.translate_def_id(def_id);
1434 Ok(dcx.tcx().lookup_adt_def(def_id))
1440 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1441 pub enum AdtKind { Struct, Enum }
1443 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1444 pub enum VariantKind { Struct, Tuple, Unit }
1447 pub fn from_variant_data(vdata: &hir::VariantData) -> Self {
1449 hir::VariantData::Struct(..) => VariantKind::Struct,
1450 hir::VariantData::Tuple(..) => VariantKind::Tuple,
1451 hir::VariantData::Unit(..) => VariantKind::Unit,
1456 impl<'tcx, 'container> AdtDefData<'tcx, 'container> {
1457 fn new(tcx: &ctxt<'tcx>,
1460 variants: Vec<VariantDefData<'tcx, 'container>>) -> Self {
1461 let mut flags = AdtFlags::NO_ADT_FLAGS;
1462 let attrs = tcx.get_attrs(did);
1463 if attr::contains_name(&attrs, "fundamental") {
1464 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1466 if attr::contains_name(&attrs, "unsafe_no_drop_flag") {
1467 flags = flags | AdtFlags::IS_NO_DROP_FLAG;
1469 if tcx.lookup_simd(did) {
1470 flags = flags | AdtFlags::IS_SIMD;
1472 if Some(did) == tcx.lang_items.phantom_data() {
1473 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1475 if let AdtKind::Enum = kind {
1476 flags = flags | AdtFlags::IS_ENUM;
1481 flags: Cell::new(flags),
1482 destructor: Cell::new(None)
1486 fn calculate_dtorck(&'tcx self, tcx: &ctxt<'tcx>) {
1487 if tcx.is_adt_dtorck(self) {
1488 self.flags.set(self.flags.get() | AdtFlags::IS_DTORCK);
1490 self.flags.set(self.flags.get() | AdtFlags::IS_DTORCK_VALID)
1493 /// Returns the kind of the ADT - Struct or Enum.
1495 pub fn adt_kind(&self) -> AdtKind {
1496 if self.flags.get().intersects(AdtFlags::IS_ENUM) {
1503 /// Returns whether this is a dtorck type. If this returns
1504 /// true, this type being safe for destruction requires it to be
1505 /// alive; Otherwise, only the contents are required to be.
1507 pub fn is_dtorck(&'tcx self, tcx: &ctxt<'tcx>) -> bool {
1508 if !self.flags.get().intersects(AdtFlags::IS_DTORCK_VALID) {
1509 self.calculate_dtorck(tcx)
1511 self.flags.get().intersects(AdtFlags::IS_DTORCK)
1514 /// Returns whether this type is #[fundamental] for the purposes
1515 /// of coherence checking.
1517 pub fn is_fundamental(&self) -> bool {
1518 self.flags.get().intersects(AdtFlags::IS_FUNDAMENTAL)
1522 pub fn is_simd(&self) -> bool {
1523 self.flags.get().intersects(AdtFlags::IS_SIMD)
1526 /// Returns true if this is PhantomData<T>.
1528 pub fn is_phantom_data(&self) -> bool {
1529 self.flags.get().intersects(AdtFlags::IS_PHANTOM_DATA)
1532 /// Returns whether this type has a destructor.
1533 pub fn has_dtor(&self) -> bool {
1534 match self.dtor_kind() {
1536 TraitDtor(..) => true
1540 /// Asserts this is a struct and returns the struct's unique
1542 pub fn struct_variant(&self) -> &VariantDefData<'tcx, 'container> {
1543 assert!(self.adt_kind() == AdtKind::Struct);
1548 pub fn type_scheme(&self, tcx: &ctxt<'tcx>) -> TypeScheme<'tcx> {
1549 tcx.lookup_item_type(self.did)
1553 pub fn predicates(&self, tcx: &ctxt<'tcx>) -> GenericPredicates<'tcx> {
1554 tcx.lookup_predicates(self.did)
1557 /// Returns an iterator over all fields contained
1560 pub fn all_fields(&self) ->
1562 slice::Iter<VariantDefData<'tcx, 'container>>,
1563 slice::Iter<FieldDefData<'tcx, 'container>>,
1564 for<'s> fn(&'s VariantDefData<'tcx, 'container>)
1565 -> slice::Iter<'s, FieldDefData<'tcx, 'container>>
1567 self.variants.iter().flat_map(VariantDefData::fields_iter)
1571 pub fn is_empty(&self) -> bool {
1572 self.variants.is_empty()
1576 pub fn is_univariant(&self) -> bool {
1577 self.variants.len() == 1
1580 pub fn is_payloadfree(&self) -> bool {
1581 !self.variants.is_empty() &&
1582 self.variants.iter().all(|v| v.fields.is_empty())
1585 pub fn variant_with_id(&self, vid: DefId) -> &VariantDefData<'tcx, 'container> {
1588 .find(|v| v.did == vid)
1589 .expect("variant_with_id: unknown variant")
1592 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1595 .position(|v| v.did == vid)
1596 .expect("variant_index_with_id: unknown variant")
1599 pub fn variant_of_def(&self, def: Def) -> &VariantDefData<'tcx, 'container> {
1601 Def::Variant(_, vid) => self.variant_with_id(vid),
1602 Def::Struct(..) | Def::TyAlias(..) => self.struct_variant(),
1603 _ => panic!("unexpected def {:?} in variant_of_def", def)
1607 pub fn destructor(&self) -> Option<DefId> {
1608 self.destructor.get()
1611 pub fn set_destructor(&self, dtor: DefId) {
1612 self.destructor.set(Some(dtor));
1615 pub fn dtor_kind(&self) -> DtorKind {
1616 match self.destructor.get() {
1618 TraitDtor(!self.flags.get().intersects(AdtFlags::IS_NO_DROP_FLAG))
1625 impl<'tcx, 'container> VariantDefData<'tcx, 'container> {
1627 fn fields_iter(&self) -> slice::Iter<FieldDefData<'tcx, 'container>> {
1631 pub fn kind(&self) -> VariantKind {
1635 pub fn is_tuple_struct(&self) -> bool {
1636 self.kind() == VariantKind::Tuple
1640 pub fn find_field_named(&self,
1642 -> Option<&FieldDefData<'tcx, 'container>> {
1643 self.fields.iter().find(|f| f.name == name)
1647 pub fn index_of_field_named(&self,
1650 self.fields.iter().position(|f| f.name == name)
1654 pub fn field_named(&self, name: ast::Name) -> &FieldDefData<'tcx, 'container> {
1655 self.find_field_named(name).unwrap()
1659 impl<'tcx, 'container> FieldDefData<'tcx, 'container> {
1660 pub fn new(did: DefId,
1662 vis: hir::Visibility) -> Self {
1667 ty: ivar::TyIVar::new()
1671 pub fn ty(&self, tcx: &ctxt<'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1672 self.unsubst_ty().subst(tcx, subst)
1675 pub fn unsubst_ty(&self) -> Ty<'tcx> {
1676 self.ty.unwrap(DepNode::FieldTy(self.did))
1679 pub fn fulfill_ty(&self, ty: Ty<'container>) {
1680 self.ty.fulfill(DepNode::FieldTy(self.did), ty);
1684 /// Records the substitutions used to translate the polytype for an
1685 /// item into the monotype of an item reference.
1687 pub struct ItemSubsts<'tcx> {
1688 pub substs: Substs<'tcx>,
1691 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Debug, RustcEncodable, RustcDecodable)]
1692 pub enum ClosureKind {
1693 // Warning: Ordering is significant here! The ordering is chosen
1694 // because the trait Fn is a subtrait of FnMut and so in turn, and
1695 // hence we order it so that Fn < FnMut < FnOnce.
1702 pub fn trait_did(&self, cx: &ctxt) -> DefId {
1703 let result = match *self {
1704 FnClosureKind => cx.lang_items.require(FnTraitLangItem),
1705 FnMutClosureKind => {
1706 cx.lang_items.require(FnMutTraitLangItem)
1708 FnOnceClosureKind => {
1709 cx.lang_items.require(FnOnceTraitLangItem)
1713 Ok(trait_did) => trait_did,
1714 Err(err) => cx.sess.fatal(&err[..]),
1718 /// True if this a type that impls this closure kind
1719 /// must also implement `other`.
1720 pub fn extends(self, other: ty::ClosureKind) -> bool {
1721 match (self, other) {
1722 (FnClosureKind, FnClosureKind) => true,
1723 (FnClosureKind, FnMutClosureKind) => true,
1724 (FnClosureKind, FnOnceClosureKind) => true,
1725 (FnMutClosureKind, FnMutClosureKind) => true,
1726 (FnMutClosureKind, FnOnceClosureKind) => true,
1727 (FnOnceClosureKind, FnOnceClosureKind) => true,
1733 impl<'tcx> TyS<'tcx> {
1734 /// Iterator that walks `self` and any types reachable from
1735 /// `self`, in depth-first order. Note that just walks the types
1736 /// that appear in `self`, it does not descend into the fields of
1737 /// structs or variants. For example:
1740 /// isize => { isize }
1741 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
1742 /// [isize] => { [isize], isize }
1744 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
1745 TypeWalker::new(self)
1748 /// Iterator that walks the immediate children of `self`. Hence
1749 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
1750 /// (but not `i32`, like `walk`).
1751 pub fn walk_shallow(&'tcx self) -> IntoIter<Ty<'tcx>> {
1752 walk::walk_shallow(self)
1755 /// Walks `ty` and any types appearing within `ty`, invoking the
1756 /// callback `f` on each type. If the callback returns false, then the
1757 /// children of the current type are ignored.
1759 /// Note: prefer `ty.walk()` where possible.
1760 pub fn maybe_walk<F>(&'tcx self, mut f: F)
1761 where F : FnMut(Ty<'tcx>) -> bool
1763 let mut walker = self.walk();
1764 while let Some(ty) = walker.next() {
1766 walker.skip_current_subtree();
1772 impl<'tcx> ItemSubsts<'tcx> {
1773 pub fn empty() -> ItemSubsts<'tcx> {
1774 ItemSubsts { substs: Substs::empty() }
1777 pub fn is_noop(&self) -> bool {
1778 self.substs.is_noop()
1782 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1783 pub enum LvaluePreference {
1788 impl LvaluePreference {
1789 pub fn from_mutbl(m: hir::Mutability) -> Self {
1791 hir::MutMutable => PreferMutLvalue,
1792 hir::MutImmutable => NoPreference,
1797 /// Helper for looking things up in the various maps that are populated during
1798 /// typeck::collect (e.g., `cx.impl_or_trait_items`, `cx.tcache`, etc). All of
1799 /// these share the pattern that if the id is local, it should have been loaded
1800 /// into the map by the `typeck::collect` phase. If the def-id is external,
1801 /// then we have to go consult the crate loading code (and cache the result for
1803 fn lookup_locally_or_in_crate_store<M, F>(descr: &str,
1808 M: MemoizationMap<Key=DefId>,
1809 F: FnOnce() -> M::Value,
1811 map.memoize(def_id, || {
1812 if def_id.is_local() {
1813 panic!("No def'n found for {:?} in tcx.{}", def_id, descr);
1820 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
1822 hir::MutMutable => MutBorrow,
1823 hir::MutImmutable => ImmBorrow,
1827 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
1828 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
1829 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
1831 pub fn to_mutbl_lossy(self) -> hir::Mutability {
1833 MutBorrow => hir::MutMutable,
1834 ImmBorrow => hir::MutImmutable,
1836 // We have no type corresponding to a unique imm borrow, so
1837 // use `&mut`. It gives all the capabilities of an `&uniq`
1838 // and hence is a safe "over approximation".
1839 UniqueImmBorrow => hir::MutMutable,
1843 pub fn to_user_str(&self) -> &'static str {
1845 MutBorrow => "mutable",
1846 ImmBorrow => "immutable",
1847 UniqueImmBorrow => "uniquely immutable",
1852 impl<'tcx> ctxt<'tcx> {
1853 pub fn node_id_to_type(&self, id: NodeId) -> Ty<'tcx> {
1854 match self.node_id_to_type_opt(id) {
1856 None => self.sess.bug(
1857 &format!("node_id_to_type: no type for node `{}`",
1858 self.map.node_to_string(id)))
1862 pub fn node_id_to_type_opt(&self, id: NodeId) -> Option<Ty<'tcx>> {
1863 self.tables.borrow().node_types.get(&id).cloned()
1866 pub fn node_id_item_substs(&self, id: NodeId) -> ItemSubsts<'tcx> {
1867 match self.tables.borrow().item_substs.get(&id) {
1868 None => ItemSubsts::empty(),
1869 Some(ts) => ts.clone(),
1873 // Returns the type of a pattern as a monotype. Like @expr_ty, this function
1874 // doesn't provide type parameter substitutions.
1875 pub fn pat_ty(&self, pat: &hir::Pat) -> Ty<'tcx> {
1876 self.node_id_to_type(pat.id)
1878 pub fn pat_ty_opt(&self, pat: &hir::Pat) -> Option<Ty<'tcx>> {
1879 self.node_id_to_type_opt(pat.id)
1882 // Returns the type of an expression as a monotype.
1884 // NB (1): This is the PRE-ADJUSTMENT TYPE for the expression. That is, in
1885 // some cases, we insert `AutoAdjustment` annotations such as auto-deref or
1886 // auto-ref. The type returned by this function does not consider such
1887 // adjustments. See `expr_ty_adjusted()` instead.
1889 // NB (2): This type doesn't provide type parameter substitutions; e.g. if you
1890 // ask for the type of "id" in "id(3)", it will return "fn(&isize) -> isize"
1891 // instead of "fn(ty) -> T with T = isize".
1892 pub fn expr_ty(&self, expr: &hir::Expr) -> Ty<'tcx> {
1893 self.node_id_to_type(expr.id)
1896 pub fn expr_ty_opt(&self, expr: &hir::Expr) -> Option<Ty<'tcx>> {
1897 self.node_id_to_type_opt(expr.id)
1900 /// Returns the type of `expr`, considering any `AutoAdjustment`
1901 /// entry recorded for that expression.
1903 /// It would almost certainly be better to store the adjusted ty in with
1904 /// the `AutoAdjustment`, but I opted not to do this because it would
1905 /// require serializing and deserializing the type and, although that's not
1906 /// hard to do, I just hate that code so much I didn't want to touch it
1907 /// unless it was to fix it properly, which seemed a distraction from the
1908 /// thread at hand! -nmatsakis
1909 pub fn expr_ty_adjusted(&self, expr: &hir::Expr) -> Ty<'tcx> {
1911 .adjust(self, expr.span, expr.id,
1912 self.tables.borrow().adjustments.get(&expr.id),
1914 self.tables.borrow().method_map.get(&method_call).map(|method| method.ty)
1918 pub fn expr_span(&self, id: NodeId) -> Span {
1919 match self.map.find(id) {
1920 Some(ast_map::NodeExpr(e)) => {
1924 self.sess.bug(&format!("Node id {} is not an expr: {:?}",
1928 self.sess.bug(&format!("Node id {} is not present \
1929 in the node map", id));
1934 pub fn local_var_name_str(&self, id: NodeId) -> InternedString {
1935 match self.map.find(id) {
1936 Some(ast_map::NodeLocal(pat)) => {
1938 hir::PatIdent(_, ref path1, _) => path1.node.name.as_str(),
1940 self.sess.bug(&format!("Variable id {} maps to {:?}, not local", id, pat));
1944 r => self.sess.bug(&format!("Variable id {} maps to {:?}, not local", id, r)),
1948 pub fn resolve_expr(&self, expr: &hir::Expr) -> Def {
1949 match self.def_map.borrow().get(&expr.id) {
1950 Some(def) => def.full_def(),
1952 self.sess.span_bug(expr.span, &format!(
1953 "no def-map entry for expr {}", expr.id));
1958 pub fn expr_is_lval(&self, expr: &hir::Expr) -> bool {
1960 hir::ExprPath(..) => {
1961 // We can't use resolve_expr here, as this needs to run on broken
1962 // programs. We don't need to through - associated items are all
1964 match self.def_map.borrow().get(&expr.id) {
1965 Some(&def::PathResolution {
1966 base_def: Def::Static(..), ..
1967 }) | Some(&def::PathResolution {
1968 base_def: Def::Upvar(..), ..
1969 }) | Some(&def::PathResolution {
1970 base_def: Def::Local(..), ..
1974 Some(&def::PathResolution { base_def: Def::Err, .. })=> true,
1976 None => self.sess.span_bug(expr.span, &format!(
1977 "no def for path {}", expr.id))
1981 hir::ExprType(ref e, _) => {
1982 self.expr_is_lval(e)
1985 hir::ExprUnary(hir::UnDeref, _) |
1986 hir::ExprField(..) |
1987 hir::ExprTupField(..) |
1988 hir::ExprIndex(..) => {
1993 hir::ExprMethodCall(..) |
1994 hir::ExprStruct(..) |
1995 hir::ExprRange(..) |
1998 hir::ExprMatch(..) |
1999 hir::ExprClosure(..) |
2000 hir::ExprBlock(..) |
2001 hir::ExprRepeat(..) |
2003 hir::ExprBreak(..) |
2004 hir::ExprAgain(..) |
2006 hir::ExprWhile(..) |
2008 hir::ExprAssign(..) |
2009 hir::ExprInlineAsm(..) |
2010 hir::ExprAssignOp(..) |
2012 hir::ExprUnary(..) |
2014 hir::ExprAddrOf(..) |
2015 hir::ExprBinary(..) |
2016 hir::ExprCast(..) => {
2022 pub fn provided_trait_methods(&self, id: DefId) -> Vec<Rc<Method<'tcx>>> {
2023 if let Some(id) = self.map.as_local_node_id(id) {
2024 if let ItemTrait(_, _, _, ref ms) = self.map.expect_item(id).node {
2025 ms.iter().filter_map(|ti| {
2026 if let hir::MethodTraitItem(_, Some(_)) = ti.node {
2027 match self.impl_or_trait_item(self.map.local_def_id(ti.id)) {
2028 MethodTraitItem(m) => Some(m),
2030 self.sess.bug("provided_trait_methods(): \
2031 non-method item found from \
2032 looking up provided method?!")
2040 self.sess.bug(&format!("provided_trait_methods: `{:?}` is not a trait", id))
2043 self.sess.cstore.provided_trait_methods(self, id)
2047 pub fn associated_consts(&self, id: DefId) -> Vec<Rc<AssociatedConst<'tcx>>> {
2048 if let Some(id) = self.map.as_local_node_id(id) {
2049 match self.map.expect_item(id).node {
2050 ItemTrait(_, _, _, ref tis) => {
2051 tis.iter().filter_map(|ti| {
2052 if let hir::ConstTraitItem(_, _) = ti.node {
2053 match self.impl_or_trait_item(self.map.local_def_id(ti.id)) {
2054 ConstTraitItem(ac) => Some(ac),
2056 self.sess.bug("associated_consts(): \
2057 non-const item found from \
2058 looking up a constant?!")
2066 ItemImpl(_, _, _, _, _, ref iis) => {
2067 iis.iter().filter_map(|ii| {
2068 if let hir::ImplItemKind::Const(_, _) = ii.node {
2069 match self.impl_or_trait_item(self.map.local_def_id(ii.id)) {
2070 ConstTraitItem(ac) => Some(ac),
2072 self.sess.bug("associated_consts(): \
2073 non-const item found from \
2074 looking up a constant?!")
2083 self.sess.bug(&format!("associated_consts: `{:?}` is not a trait \
2088 self.sess.cstore.associated_consts(self, id)
2092 pub fn trait_impl_polarity(&self, id: DefId) -> Option<hir::ImplPolarity> {
2093 if let Some(id) = self.map.as_local_node_id(id) {
2094 match self.map.find(id) {
2095 Some(ast_map::NodeItem(item)) => {
2097 hir::ItemImpl(_, polarity, _, _, _, _) => Some(polarity),
2104 self.sess.cstore.impl_polarity(id)
2108 pub fn custom_coerce_unsized_kind(&self, did: DefId) -> adjustment::CustomCoerceUnsized {
2109 self.custom_coerce_unsized_kinds.memoize(did, || {
2110 let (kind, src) = if did.krate != LOCAL_CRATE {
2111 (self.sess.cstore.custom_coerce_unsized_kind(did), "external")
2119 self.sess.bug(&format!("custom_coerce_unsized_kind: \
2120 {} impl `{}` is missing its kind",
2121 src, self.item_path_str(did)));
2127 pub fn impl_or_trait_item(&self, id: DefId) -> ImplOrTraitItem<'tcx> {
2128 lookup_locally_or_in_crate_store(
2129 "impl_or_trait_items", id, &self.impl_or_trait_items,
2130 || self.sess.cstore.impl_or_trait_item(self, id))
2133 pub fn trait_item_def_ids(&self, id: DefId) -> Rc<Vec<ImplOrTraitItemId>> {
2134 lookup_locally_or_in_crate_store(
2135 "trait_item_def_ids", id, &self.trait_item_def_ids,
2136 || Rc::new(self.sess.cstore.trait_item_def_ids(id)))
2139 /// Returns the trait-ref corresponding to a given impl, or None if it is
2140 /// an inherent impl.
2141 pub fn impl_trait_ref(&self, id: DefId) -> Option<TraitRef<'tcx>> {
2142 lookup_locally_or_in_crate_store(
2143 "impl_trait_refs", id, &self.impl_trait_refs,
2144 || self.sess.cstore.impl_trait_ref(self, id))
2147 /// Returns whether this DefId refers to an impl
2148 pub fn is_impl(&self, id: DefId) -> bool {
2149 if let Some(id) = self.map.as_local_node_id(id) {
2150 if let Some(ast_map::NodeItem(
2151 &hir::Item { node: hir::ItemImpl(..), .. })) = self.map.find(id) {
2157 self.sess.cstore.is_impl(id)
2161 pub fn trait_ref_to_def_id(&self, tr: &hir::TraitRef) -> DefId {
2162 self.def_map.borrow().get(&tr.ref_id).expect("no def-map entry for trait").def_id()
2165 pub fn item_path_str(&self, id: DefId) -> String {
2166 self.with_path(id, |path| ast_map::path_to_string(path))
2169 pub fn def_path(&self, id: DefId) -> ast_map::DefPath {
2171 self.map.def_path(id)
2173 self.sess.cstore.def_path(id)
2177 pub fn with_path<T, F>(&self, id: DefId, f: F) -> T where
2178 F: FnOnce(ast_map::PathElems) -> T,
2180 if let Some(id) = self.map.as_local_node_id(id) {
2181 self.map.with_path(id, f)
2183 f(self.sess.cstore.item_path(id).iter().cloned().chain(LinkedPath::empty()))
2187 pub fn item_name(&self, id: DefId) -> ast::Name {
2188 if let Some(id) = self.map.as_local_node_id(id) {
2189 self.map.get_path_elem(id).name()
2191 self.sess.cstore.item_name(id)
2195 // Register a given item type
2196 pub fn register_item_type(&self, did: DefId, ty: TypeScheme<'tcx>) {
2197 self.tcache.borrow_mut().insert(did, ty);
2200 // If the given item is in an external crate, looks up its type and adds it to
2201 // the type cache. Returns the type parameters and type.
2202 pub fn lookup_item_type(&self, did: DefId) -> TypeScheme<'tcx> {
2203 lookup_locally_or_in_crate_store(
2204 "tcache", did, &self.tcache,
2205 || self.sess.cstore.item_type(self, did))
2208 /// Given the did of a trait, returns its canonical trait ref.
2209 pub fn lookup_trait_def(&self, did: DefId) -> &'tcx TraitDef<'tcx> {
2210 lookup_locally_or_in_crate_store(
2211 "trait_defs", did, &self.trait_defs,
2212 || self.alloc_trait_def(self.sess.cstore.trait_def(self, did))
2216 /// Given the did of an ADT, return a master reference to its
2217 /// definition. Unless you are planning on fulfilling the ADT's fields,
2218 /// use lookup_adt_def instead.
2219 pub fn lookup_adt_def_master(&self, did: DefId) -> AdtDefMaster<'tcx> {
2220 lookup_locally_or_in_crate_store(
2221 "adt_defs", did, &self.adt_defs,
2222 || self.sess.cstore.adt_def(self, did)
2226 /// Given the did of an ADT, return a reference to its definition.
2227 pub fn lookup_adt_def(&self, did: DefId) -> AdtDef<'tcx> {
2228 // when reverse-variance goes away, a transmute::<AdtDefMaster,AdtDef>
2229 // woud be needed here.
2230 self.lookup_adt_def_master(did)
2233 /// Given the did of an item, returns its full set of predicates.
2234 pub fn lookup_predicates(&self, did: DefId) -> GenericPredicates<'tcx> {
2235 lookup_locally_or_in_crate_store(
2236 "predicates", did, &self.predicates,
2237 || self.sess.cstore.item_predicates(self, did))
2240 /// Given the did of a trait, returns its superpredicates.
2241 pub fn lookup_super_predicates(&self, did: DefId) -> GenericPredicates<'tcx> {
2242 lookup_locally_or_in_crate_store(
2243 "super_predicates", did, &self.super_predicates,
2244 || self.sess.cstore.item_super_predicates(self, did))
2247 /// If `type_needs_drop` returns true, then `ty` is definitely
2248 /// non-copy and *might* have a destructor attached; if it returns
2249 /// false, then `ty` definitely has no destructor (i.e. no drop glue).
2251 /// (Note that this implies that if `ty` has a destructor attached,
2252 /// then `type_needs_drop` will definitely return `true` for `ty`.)
2253 pub fn type_needs_drop_given_env<'a>(&self,
2255 param_env: &ty::ParameterEnvironment<'a,'tcx>) -> bool {
2256 // Issue #22536: We first query type_moves_by_default. It sees a
2257 // normalized version of the type, and therefore will definitely
2258 // know whether the type implements Copy (and thus needs no
2259 // cleanup/drop/zeroing) ...
2260 let implements_copy = !ty.moves_by_default(param_env, DUMMY_SP);
2262 if implements_copy { return false; }
2264 // ... (issue #22536 continued) but as an optimization, still use
2265 // prior logic of asking if the `needs_drop` bit is set; we need
2266 // not zero non-Copy types if they have no destructor.
2268 // FIXME(#22815): Note that calling `ty::type_contents` is a
2269 // conservative heuristic; it may report that `needs_drop` is set
2270 // when actual type does not actually have a destructor associated
2271 // with it. But since `ty` absolutely did not have the `Copy`
2272 // bound attached (see above), it is sound to treat it as having a
2273 // destructor (e.g. zero its memory on move).
2275 let contents = ty.type_contents(self);
2276 debug!("type_needs_drop ty={:?} contents={:?}", ty, contents);
2277 contents.needs_drop(self)
2280 /// Get the attributes of a definition.
2281 pub fn get_attrs(&self, did: DefId) -> Cow<'tcx, [ast::Attribute]> {
2282 if let Some(id) = self.map.as_local_node_id(did) {
2283 Cow::Borrowed(self.map.attrs(id))
2285 Cow::Owned(self.sess.cstore.item_attrs(did))
2289 /// Determine whether an item is annotated with an attribute
2290 pub fn has_attr(&self, did: DefId, attr: &str) -> bool {
2291 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2294 /// Determine whether an item is annotated with `#[repr(packed)]`
2295 pub fn lookup_packed(&self, did: DefId) -> bool {
2296 self.lookup_repr_hints(did).contains(&attr::ReprPacked)
2299 /// Determine whether an item is annotated with `#[simd]`
2300 pub fn lookup_simd(&self, did: DefId) -> bool {
2301 self.has_attr(did, "simd")
2302 || self.lookup_repr_hints(did).contains(&attr::ReprSimd)
2305 pub fn item_variances(&self, item_id: DefId) -> Rc<ItemVariances> {
2306 lookup_locally_or_in_crate_store(
2307 "item_variance_map", item_id, &self.item_variance_map,
2308 || Rc::new(self.sess.cstore.item_variances(item_id)))
2311 pub fn trait_has_default_impl(&self, trait_def_id: DefId) -> bool {
2312 self.populate_implementations_for_trait_if_necessary(trait_def_id);
2314 let def = self.lookup_trait_def(trait_def_id);
2315 def.flags.get().intersects(TraitFlags::HAS_DEFAULT_IMPL)
2318 /// Records a trait-to-implementation mapping.
2319 pub fn record_trait_has_default_impl(&self, trait_def_id: DefId) {
2320 let def = self.lookup_trait_def(trait_def_id);
2321 def.flags.set(def.flags.get() | TraitFlags::HAS_DEFAULT_IMPL)
2324 /// Load primitive inherent implementations if necessary
2325 pub fn populate_implementations_for_primitive_if_necessary(&self,
2326 primitive_def_id: DefId) {
2327 if primitive_def_id.is_local() {
2331 // The primitive is not local, hence we are reading this out
2333 let _ignore = self.dep_graph.in_ignore();
2335 if self.populated_external_primitive_impls.borrow().contains(&primitive_def_id) {
2339 debug!("populate_implementations_for_primitive_if_necessary: searching for {:?}",
2342 let impl_items = self.sess.cstore.impl_items(primitive_def_id);
2344 // Store the implementation info.
2345 self.impl_items.borrow_mut().insert(primitive_def_id, impl_items);
2346 self.populated_external_primitive_impls.borrow_mut().insert(primitive_def_id);
2349 /// Populates the type context with all the inherent implementations for
2350 /// the given type if necessary.
2351 pub fn populate_inherent_implementations_for_type_if_necessary(&self,
2353 if type_id.is_local() {
2357 // The type is not local, hence we are reading this out of
2358 // metadata and don't need to track edges.
2359 let _ignore = self.dep_graph.in_ignore();
2361 if self.populated_external_types.borrow().contains(&type_id) {
2365 debug!("populate_inherent_implementations_for_type_if_necessary: searching for {:?}",
2368 let inherent_impls = self.sess.cstore.inherent_implementations_for_type(type_id);
2369 for &impl_def_id in &inherent_impls {
2370 // Store the implementation info.
2371 let impl_items = self.sess.cstore.impl_items(impl_def_id);
2372 self.impl_items.borrow_mut().insert(impl_def_id, impl_items);
2375 self.inherent_impls.borrow_mut().insert(type_id, Rc::new(inherent_impls));
2376 self.populated_external_types.borrow_mut().insert(type_id);
2379 /// Populates the type context with all the implementations for the given
2380 /// trait if necessary.
2381 pub fn populate_implementations_for_trait_if_necessary(&self, trait_id: DefId) {
2382 if trait_id.is_local() {
2386 // The type is not local, hence we are reading this out of
2387 // metadata and don't need to track edges.
2388 let _ignore = self.dep_graph.in_ignore();
2390 let def = self.lookup_trait_def(trait_id);
2391 if def.flags.get().intersects(TraitFlags::IMPLS_VALID) {
2395 debug!("populate_implementations_for_trait_if_necessary: searching for {:?}", def);
2397 if self.sess.cstore.is_defaulted_trait(trait_id) {
2398 self.record_trait_has_default_impl(trait_id);
2401 for impl_def_id in self.sess.cstore.implementations_of_trait(trait_id) {
2402 let impl_items = self.sess.cstore.impl_items(impl_def_id);
2403 let trait_ref = self.impl_trait_ref(impl_def_id).unwrap();
2404 // Record the trait->implementation mapping.
2405 def.record_impl(self, impl_def_id, trait_ref);
2407 // For any methods that use a default implementation, add them to
2408 // the map. This is a bit unfortunate.
2409 for impl_item_def_id in &impl_items {
2410 let method_def_id = impl_item_def_id.def_id();
2411 // load impl items eagerly for convenience
2412 // FIXME: we may want to load these lazily
2413 self.impl_or_trait_item(method_def_id);
2416 // Store the implementation info.
2417 self.impl_items.borrow_mut().insert(impl_def_id, impl_items);
2420 def.flags.set(def.flags.get() | TraitFlags::IMPLS_VALID);
2423 pub fn closure_kind(&self, def_id: DefId) -> ty::ClosureKind {
2424 Tables::closure_kind(&self.tables, self, def_id)
2427 pub fn closure_type(&self,
2429 substs: &ClosureSubsts<'tcx>)
2430 -> ty::ClosureTy<'tcx>
2432 Tables::closure_type(&self.tables, self, def_id, substs)
2435 /// Given the def_id of an impl, return the def_id of the trait it implements.
2436 /// If it implements no trait, return `None`.
2437 pub fn trait_id_of_impl(&self, def_id: DefId) -> Option<DefId> {
2438 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2441 /// If the given def ID describes a method belonging to an impl, return the
2442 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2443 pub fn impl_of_method(&self, def_id: DefId) -> Option<DefId> {
2444 if def_id.krate != LOCAL_CRATE {
2445 return match self.sess.cstore.impl_or_trait_item(self, def_id).container() {
2446 TraitContainer(_) => None,
2447 ImplContainer(def_id) => Some(def_id),
2450 match self.impl_or_trait_items.borrow().get(&def_id).cloned() {
2451 Some(trait_item) => {
2452 match trait_item.container() {
2453 TraitContainer(_) => None,
2454 ImplContainer(def_id) => Some(def_id),
2461 /// If the given def ID describes an item belonging to a trait (either a
2462 /// default method or an implementation of a trait method), return the ID of
2463 /// the trait that the method belongs to. Otherwise, return `None`.
2464 pub fn trait_of_item(&self, def_id: DefId) -> Option<DefId> {
2465 if def_id.krate != LOCAL_CRATE {
2466 return self.sess.cstore.trait_of_item(self, def_id);
2468 match self.impl_or_trait_items.borrow().get(&def_id).cloned() {
2469 Some(impl_or_trait_item) => {
2470 match impl_or_trait_item.container() {
2471 TraitContainer(def_id) => Some(def_id),
2472 ImplContainer(def_id) => self.trait_id_of_impl(def_id),
2479 /// If the given def ID describes an item belonging to a trait, (either a
2480 /// default method or an implementation of a trait method), return the ID of
2481 /// the method inside trait definition (this means that if the given def ID
2482 /// is already that of the original trait method, then the return value is
2484 /// Otherwise, return `None`.
2485 pub fn trait_item_of_item(&self, def_id: DefId) -> Option<ImplOrTraitItemId> {
2486 let impl_item = match self.impl_or_trait_items.borrow().get(&def_id) {
2487 Some(m) => m.clone(),
2488 None => return None,
2490 let name = impl_item.name();
2491 match self.trait_of_item(def_id) {
2492 Some(trait_did) => {
2493 self.trait_items(trait_did).iter()
2494 .find(|item| item.name() == name)
2495 .map(|item| item.id())
2501 /// Construct a parameter environment suitable for static contexts or other contexts where there
2502 /// are no free type/lifetime parameters in scope.
2503 pub fn empty_parameter_environment<'a>(&'a self)
2504 -> ParameterEnvironment<'a,'tcx> {
2506 // for an empty parameter environment, there ARE no free
2507 // regions, so it shouldn't matter what we use for the free id
2508 let free_id_outlive = self.region_maps.node_extent(ast::DUMMY_NODE_ID);
2509 ty::ParameterEnvironment { tcx: self,
2510 free_substs: Substs::empty(),
2511 caller_bounds: Vec::new(),
2512 implicit_region_bound: ty::ReEmpty,
2513 selection_cache: traits::SelectionCache::new(),
2514 evaluation_cache: traits::EvaluationCache::new(),
2515 free_id_outlive: free_id_outlive }
2518 /// Constructs and returns a substitution that can be applied to move from
2519 /// the "outer" view of a type or method to the "inner" view.
2520 /// In general, this means converting from bound parameters to
2521 /// free parameters. Since we currently represent bound/free type
2522 /// parameters in the same way, this only has an effect on regions.
2523 pub fn construct_free_substs(&self, generics: &Generics<'tcx>,
2524 free_id_outlive: CodeExtent) -> Substs<'tcx> {
2526 let mut types = VecPerParamSpace::empty();
2527 for def in generics.types.as_slice() {
2528 debug!("construct_parameter_environment(): push_types_from_defs: def={:?}",
2530 types.push(def.space, self.mk_param_from_def(def));
2533 // map bound 'a => free 'a
2534 let mut regions = VecPerParamSpace::empty();
2535 for def in generics.regions.as_slice() {
2537 ReFree(FreeRegion { scope: free_id_outlive,
2538 bound_region: BrNamed(def.def_id, def.name) });
2539 debug!("push_region_params {:?}", region);
2540 regions.push(def.space, region);
2545 regions: subst::NonerasedRegions(regions)
2549 /// See `ParameterEnvironment` struct def'n for details.
2550 /// If you were using `free_id: NodeId`, you might try `self.region_maps.item_extent(free_id)`
2551 /// for the `free_id_outlive` parameter. (But note that that is not always quite right.)
2552 pub fn construct_parameter_environment<'a>(&'a self,
2554 generics: &ty::Generics<'tcx>,
2555 generic_predicates: &ty::GenericPredicates<'tcx>,
2556 free_id_outlive: CodeExtent)
2557 -> ParameterEnvironment<'a, 'tcx>
2560 // Construct the free substs.
2563 let free_substs = self.construct_free_substs(generics, free_id_outlive);
2566 // Compute the bounds on Self and the type parameters.
2569 let bounds = generic_predicates.instantiate(self, &free_substs);
2570 let bounds = self.liberate_late_bound_regions(free_id_outlive, &ty::Binder(bounds));
2571 let predicates = bounds.predicates.into_vec();
2573 // Finally, we have to normalize the bounds in the environment, in
2574 // case they contain any associated type projections. This process
2575 // can yield errors if the put in illegal associated types, like
2576 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2577 // report these errors right here; this doesn't actually feel
2578 // right to me, because constructing the environment feels like a
2579 // kind of a "idempotent" action, but I'm not sure where would be
2580 // a better place. In practice, we construct environments for
2581 // every fn once during type checking, and we'll abort if there
2582 // are any errors at that point, so after type checking you can be
2583 // sure that this will succeed without errors anyway.
2586 let unnormalized_env = ty::ParameterEnvironment {
2588 free_substs: free_substs,
2589 implicit_region_bound: ty::ReScope(free_id_outlive),
2590 caller_bounds: predicates,
2591 selection_cache: traits::SelectionCache::new(),
2592 evaluation_cache: traits::EvaluationCache::new(),
2593 free_id_outlive: free_id_outlive,
2596 let cause = traits::ObligationCause::misc(span, free_id_outlive.node_id(&self.region_maps));
2597 traits::normalize_param_env_or_error(unnormalized_env, cause)
2600 pub fn is_method_call(&self, expr_id: NodeId) -> bool {
2601 self.tables.borrow().method_map.contains_key(&MethodCall::expr(expr_id))
2604 pub fn is_overloaded_autoderef(&self, expr_id: NodeId, autoderefs: u32) -> bool {
2605 self.tables.borrow().method_map.contains_key(&MethodCall::autoderef(expr_id,
2609 pub fn upvar_capture(&self, upvar_id: ty::UpvarId) -> Option<ty::UpvarCapture> {
2610 Some(self.tables.borrow().upvar_capture_map.get(&upvar_id).unwrap().clone())
2614 pub fn visit_all_items_in_krate<V,F>(&self,
2617 where F: FnMut(DefId) -> DepNode, V: Visitor<'tcx>
2619 dep_graph::visit_all_items_in_krate(self, dep_node_fn, visitor);
2623 /// The category of explicit self.
2624 #[derive(Clone, Copy, Eq, PartialEq, Debug)]
2625 pub enum ExplicitSelfCategory {
2628 ByReference(Region, hir::Mutability),
2632 /// A free variable referred to in a function.
2633 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
2634 pub struct Freevar {
2635 /// The variable being accessed free.
2638 // First span where it is accessed (there can be multiple).
2642 pub type FreevarMap = NodeMap<Vec<Freevar>>;
2644 pub type CaptureModeMap = NodeMap<hir::CaptureClause>;
2646 // Trait method resolution
2647 pub type TraitMap = NodeMap<Vec<DefId>>;
2649 // Map from the NodeId of a glob import to a list of items which are actually
2651 pub type GlobMap = HashMap<NodeId, HashSet<Name>>;
2653 impl<'tcx> ctxt<'tcx> {
2654 pub fn with_freevars<T, F>(&self, fid: NodeId, f: F) -> T where
2655 F: FnOnce(&[Freevar]) -> T,
2657 match self.freevars.borrow().get(&fid) {
2659 Some(d) => f(&d[..])
2663 pub fn make_substs_for_receiver_types(&self,
2664 trait_ref: &ty::TraitRef<'tcx>,
2665 method: &ty::Method<'tcx>)
2666 -> subst::Substs<'tcx>
2669 * Substitutes the values for the receiver's type parameters
2670 * that are found in method, leaving the method's type parameters
2674 let meth_tps: Vec<Ty> =
2675 method.generics.types.get_slice(subst::FnSpace)
2677 .map(|def| self.mk_param_from_def(def))
2679 let meth_regions: Vec<ty::Region> =
2680 method.generics.regions.get_slice(subst::FnSpace)
2682 .map(|def| def.to_early_bound_region())
2684 trait_ref.substs.clone().with_method(meth_tps, meth_regions)