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 hir::map as ast_map;
24 use middle::cstore::{self, LOCAL_CRATE};
25 use hir::def::{Def, PathResolution, ExportMap};
26 use hir::def_id::DefId;
27 use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
28 use middle::region::{CodeExtent, ROOT_CODE_EXTENT};
31 use ty::subst::{Subst, Substs, VecPerParamSpace};
32 use ty::walk::TypeWalker;
33 use util::common::MemoizationMap;
34 use util::nodemap::NodeSet;
35 use util::nodemap::FnvHashMap;
37 use serialize::{Encodable, Encoder, Decodable, Decoder};
40 use std::hash::{Hash, Hasher};
44 use std::vec::IntoIter;
45 use syntax::ast::{self, CrateNum, Name, NodeId};
46 use syntax::attr::{self, AttrMetaMethods};
47 use syntax::parse::token::InternedString;
48 use syntax_pos::{DUMMY_SP, Span};
50 use rustc_const_math::ConstInt;
53 use hir::{ItemImpl, ItemTrait, PatKind};
54 use hir::intravisit::Visitor;
56 pub use self::sty::{Binder, DebruijnIndex};
57 pub use self::sty::{BuiltinBound, BuiltinBounds, ExistentialBounds};
58 pub use self::sty::{BareFnTy, FnSig, PolyFnSig, FnOutput, PolyFnOutput};
59 pub use self::sty::{ClosureTy, InferTy, ParamTy, ProjectionTy, TraitTy};
60 pub use self::sty::{ClosureSubsts, TypeAndMut};
61 pub use self::sty::{TraitRef, TypeVariants, PolyTraitRef};
62 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
63 pub use self::sty::Issue32330;
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::{TyCtxt, tls};
78 pub use self::context::{CtxtArenas, Lift, Tables};
80 pub use self::trait_def::{TraitDef, TraitFlags};
103 mod structural_impls;
106 pub type Disr = ConstInt;
110 /// The complete set of all analyses described in this module. This is
111 /// produced by the driver and fed to trans and later passes.
113 pub struct CrateAnalysis<'a> {
114 pub export_map: ExportMap,
115 pub access_levels: middle::privacy::AccessLevels,
116 pub reachable: NodeSet,
118 pub glob_map: Option<hir::GlobMap>,
121 #[derive(Copy, Clone)]
128 pub fn is_present(&self) -> bool {
130 TraitDtor(..) => true,
135 pub fn has_drop_flag(&self) -> bool {
138 &TraitDtor(flag) => flag
143 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
144 pub enum ImplOrTraitItemContainer {
145 TraitContainer(DefId),
146 ImplContainer(DefId),
149 impl ImplOrTraitItemContainer {
150 pub fn id(&self) -> DefId {
152 TraitContainer(id) => id,
153 ImplContainer(id) => id,
158 /// The "header" of an impl is everything outside the body: a Self type, a trait
159 /// ref (in the case of a trait impl), and a set of predicates (from the
160 /// bounds/where clauses).
161 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
162 pub struct ImplHeader<'tcx> {
163 pub impl_def_id: DefId,
164 pub self_ty: Ty<'tcx>,
165 pub trait_ref: Option<TraitRef<'tcx>>,
166 pub predicates: Vec<Predicate<'tcx>>,
169 impl<'a, 'gcx, 'tcx> ImplHeader<'tcx> {
170 pub fn with_fresh_ty_vars(selcx: &mut traits::SelectionContext<'a, 'gcx, 'tcx>,
174 let tcx = selcx.tcx();
175 let impl_generics = tcx.lookup_item_type(impl_def_id).generics;
176 let impl_substs = selcx.infcx().fresh_substs_for_generics(DUMMY_SP, &impl_generics);
178 let header = ImplHeader {
179 impl_def_id: impl_def_id,
180 self_ty: tcx.lookup_item_type(impl_def_id).ty,
181 trait_ref: tcx.impl_trait_ref(impl_def_id),
182 predicates: tcx.lookup_predicates(impl_def_id).predicates.into_vec(),
183 }.subst(tcx, &impl_substs);
185 let traits::Normalized { value: mut header, obligations } =
186 traits::normalize(selcx, traits::ObligationCause::dummy(), &header);
188 header.predicates.extend(obligations.into_iter().map(|o| o.predicate));
194 pub enum ImplOrTraitItem<'tcx> {
195 ConstTraitItem(Rc<AssociatedConst<'tcx>>),
196 MethodTraitItem(Rc<Method<'tcx>>),
197 TypeTraitItem(Rc<AssociatedType<'tcx>>),
200 impl<'tcx> ImplOrTraitItem<'tcx> {
201 fn id(&self) -> ImplOrTraitItemId {
203 ConstTraitItem(ref associated_const) => {
204 ConstTraitItemId(associated_const.def_id)
206 MethodTraitItem(ref method) => MethodTraitItemId(method.def_id),
207 TypeTraitItem(ref associated_type) => {
208 TypeTraitItemId(associated_type.def_id)
213 pub fn def(&self) -> Def {
215 ConstTraitItem(ref associated_const) => Def::AssociatedConst(associated_const.def_id),
216 MethodTraitItem(ref method) => Def::Method(method.def_id),
217 TypeTraitItem(ref ty) => Def::AssociatedTy(ty.container.id(), ty.def_id),
221 pub fn def_id(&self) -> DefId {
223 ConstTraitItem(ref associated_const) => associated_const.def_id,
224 MethodTraitItem(ref method) => method.def_id,
225 TypeTraitItem(ref associated_type) => associated_type.def_id,
229 pub fn name(&self) -> Name {
231 ConstTraitItem(ref associated_const) => associated_const.name,
232 MethodTraitItem(ref method) => method.name,
233 TypeTraitItem(ref associated_type) => associated_type.name,
237 pub fn vis(&self) -> Visibility {
239 ConstTraitItem(ref associated_const) => associated_const.vis,
240 MethodTraitItem(ref method) => method.vis,
241 TypeTraitItem(ref associated_type) => associated_type.vis,
245 pub fn container(&self) -> ImplOrTraitItemContainer {
247 ConstTraitItem(ref associated_const) => associated_const.container,
248 MethodTraitItem(ref method) => method.container,
249 TypeTraitItem(ref associated_type) => associated_type.container,
253 pub fn as_opt_method(&self) -> Option<Rc<Method<'tcx>>> {
255 MethodTraitItem(ref m) => Some((*m).clone()),
261 #[derive(Clone, Copy, Debug)]
262 pub enum ImplOrTraitItemId {
263 ConstTraitItemId(DefId),
264 MethodTraitItemId(DefId),
265 TypeTraitItemId(DefId),
268 impl ImplOrTraitItemId {
269 pub fn def_id(&self) -> DefId {
271 ConstTraitItemId(def_id) => def_id,
272 MethodTraitItemId(def_id) => def_id,
273 TypeTraitItemId(def_id) => def_id,
278 #[derive(Clone, Debug, PartialEq, Eq, Copy)]
279 pub enum Visibility {
280 /// Visible everywhere (including in other crates).
282 /// Visible only in the given crate-local module.
284 /// Not visible anywhere in the local crate. This is the visibility of private external items.
288 pub trait NodeIdTree {
289 fn is_descendant_of(&self, node: NodeId, ancestor: NodeId) -> bool;
292 impl<'a> NodeIdTree for ast_map::Map<'a> {
293 fn is_descendant_of(&self, node: NodeId, ancestor: NodeId) -> bool {
294 let mut node_ancestor = node;
295 while node_ancestor != ancestor {
296 let node_ancestor_parent = self.get_module_parent(node_ancestor);
297 if node_ancestor_parent == node_ancestor {
300 node_ancestor = node_ancestor_parent;
307 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt) -> Self {
309 hir::Public => Visibility::Public,
310 hir::Visibility::Crate => Visibility::Restricted(ast::CRATE_NODE_ID),
311 hir::Visibility::Restricted { id, .. } => match tcx.expect_def(id) {
312 // If there is no resolution, `resolve` will have already reported an error, so
313 // assume that the visibility is public to avoid reporting more privacy errors.
314 Def::Err => Visibility::Public,
315 def => Visibility::Restricted(tcx.map.as_local_node_id(def.def_id()).unwrap()),
317 hir::Inherited => Visibility::Restricted(tcx.map.get_module_parent(id)),
321 /// Returns true if an item with this visibility is accessible from the given block.
322 pub fn is_accessible_from<T: NodeIdTree>(self, block: NodeId, tree: &T) -> bool {
323 let restriction = match self {
324 // Public items are visible everywhere.
325 Visibility::Public => return true,
326 // Private items from other crates are visible nowhere.
327 Visibility::PrivateExternal => return false,
328 // Restricted items are visible in an arbitrary local module.
329 Visibility::Restricted(module) => module,
332 tree.is_descendant_of(block, restriction)
335 /// Returns true if this visibility is at least as accessible as the given visibility
336 pub fn is_at_least<T: NodeIdTree>(self, vis: Visibility, tree: &T) -> bool {
337 let vis_restriction = match vis {
338 Visibility::Public => return self == Visibility::Public,
339 Visibility::PrivateExternal => return true,
340 Visibility::Restricted(module) => module,
343 self.is_accessible_from(vis_restriction, tree)
347 #[derive(Clone, Debug)]
348 pub struct Method<'tcx> {
350 pub generics: Generics<'tcx>,
351 pub predicates: GenericPredicates<'tcx>,
352 pub fty: &'tcx BareFnTy<'tcx>,
353 pub explicit_self: ExplicitSelfCategory,
355 pub defaultness: hir::Defaultness,
357 pub container: ImplOrTraitItemContainer,
360 impl<'tcx> Method<'tcx> {
361 pub fn new(name: Name,
362 generics: ty::Generics<'tcx>,
363 predicates: GenericPredicates<'tcx>,
364 fty: &'tcx BareFnTy<'tcx>,
365 explicit_self: ExplicitSelfCategory,
367 defaultness: hir::Defaultness,
369 container: ImplOrTraitItemContainer)
374 predicates: predicates,
376 explicit_self: explicit_self,
378 defaultness: defaultness,
380 container: container,
384 pub fn container_id(&self) -> DefId {
385 match self.container {
386 TraitContainer(id) => id,
387 ImplContainer(id) => id,
392 impl<'tcx> PartialEq for Method<'tcx> {
394 fn eq(&self, other: &Self) -> bool { self.def_id == other.def_id }
397 impl<'tcx> Eq for Method<'tcx> {}
399 impl<'tcx> Hash for Method<'tcx> {
401 fn hash<H: Hasher>(&self, s: &mut H) {
406 #[derive(Clone, Copy, Debug)]
407 pub struct AssociatedConst<'tcx> {
411 pub defaultness: hir::Defaultness,
413 pub container: ImplOrTraitItemContainer,
417 #[derive(Clone, Copy, Debug)]
418 pub struct AssociatedType<'tcx> {
420 pub ty: Option<Ty<'tcx>>,
422 pub defaultness: hir::Defaultness,
424 pub container: ImplOrTraitItemContainer,
427 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable)]
428 pub struct ItemVariances {
429 pub types: VecPerParamSpace<Variance>,
430 pub regions: VecPerParamSpace<Variance>,
433 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
435 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
436 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
437 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
438 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
441 #[derive(Clone, Copy, Debug)]
442 pub struct MethodCallee<'tcx> {
443 /// Impl method ID, for inherent methods, or trait method ID, otherwise.
446 pub substs: &'tcx subst::Substs<'tcx>
449 /// With method calls, we store some extra information in
450 /// side tables (i.e method_map). We use
451 /// MethodCall as a key to index into these tables instead of
452 /// just directly using the expression's NodeId. The reason
453 /// for this being that we may apply adjustments (coercions)
454 /// with the resulting expression also needing to use the
455 /// side tables. The problem with this is that we don't
456 /// assign a separate NodeId to this new expression
457 /// and so it would clash with the base expression if both
458 /// needed to add to the side tables. Thus to disambiguate
459 /// we also keep track of whether there's an adjustment in
461 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
462 pub struct MethodCall {
468 pub fn expr(id: NodeId) -> MethodCall {
475 pub fn autoderef(expr_id: NodeId, autoderef: u32) -> MethodCall {
478 autoderef: 1 + autoderef
483 // maps from an expression id that corresponds to a method call to the details
484 // of the method to be invoked
485 pub type MethodMap<'tcx> = FnvHashMap<MethodCall, MethodCallee<'tcx>>;
487 // Contains information needed to resolve types and (in the future) look up
488 // the types of AST nodes.
489 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
490 pub struct CReaderCacheKey {
495 /// Describes the fragment-state associated with a NodeId.
497 /// Currently only unfragmented paths have entries in the table,
498 /// but longer-term this enum is expected to expand to also
499 /// include data for fragmented paths.
500 #[derive(Copy, Clone, Debug)]
501 pub enum FragmentInfo {
502 Moved { var: NodeId, move_expr: NodeId },
503 Assigned { var: NodeId, assign_expr: NodeId, assignee_id: NodeId },
506 // Flags that we track on types. These flags are propagated upwards
507 // through the type during type construction, so that we can quickly
508 // check whether the type has various kinds of types in it without
509 // recursing over the type itself.
511 flags TypeFlags: u32 {
512 const HAS_PARAMS = 1 << 0,
513 const HAS_SELF = 1 << 1,
514 const HAS_TY_INFER = 1 << 2,
515 const HAS_RE_INFER = 1 << 3,
516 const HAS_RE_SKOL = 1 << 4,
517 const HAS_RE_EARLY_BOUND = 1 << 5,
518 const HAS_FREE_REGIONS = 1 << 6,
519 const HAS_TY_ERR = 1 << 7,
520 const HAS_PROJECTION = 1 << 8,
521 const HAS_TY_CLOSURE = 1 << 9,
523 // true if there are "names" of types and regions and so forth
524 // that are local to a particular fn
525 const HAS_LOCAL_NAMES = 1 << 10,
527 // Present if the type belongs in a local type context.
528 // Only set for TyInfer other than Fresh.
529 const KEEP_IN_LOCAL_TCX = 1 << 11,
531 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
532 TypeFlags::HAS_SELF.bits |
533 TypeFlags::HAS_RE_EARLY_BOUND.bits,
535 // Flags representing the nominal content of a type,
536 // computed by FlagsComputation. If you add a new nominal
537 // flag, it should be added here too.
538 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
539 TypeFlags::HAS_SELF.bits |
540 TypeFlags::HAS_TY_INFER.bits |
541 TypeFlags::HAS_RE_INFER.bits |
542 TypeFlags::HAS_RE_EARLY_BOUND.bits |
543 TypeFlags::HAS_FREE_REGIONS.bits |
544 TypeFlags::HAS_TY_ERR.bits |
545 TypeFlags::HAS_PROJECTION.bits |
546 TypeFlags::HAS_TY_CLOSURE.bits |
547 TypeFlags::HAS_LOCAL_NAMES.bits |
548 TypeFlags::KEEP_IN_LOCAL_TCX.bits,
550 // Caches for type_is_sized, type_moves_by_default
551 const SIZEDNESS_CACHED = 1 << 16,
552 const IS_SIZED = 1 << 17,
553 const MOVENESS_CACHED = 1 << 18,
554 const MOVES_BY_DEFAULT = 1 << 19,
558 pub struct TyS<'tcx> {
559 pub sty: TypeVariants<'tcx>,
560 pub flags: Cell<TypeFlags>,
562 // the maximal depth of any bound regions appearing in this type.
566 impl<'tcx> PartialEq for TyS<'tcx> {
568 fn eq(&self, other: &TyS<'tcx>) -> bool {
569 // (self as *const _) == (other as *const _)
570 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
573 impl<'tcx> Eq for TyS<'tcx> {}
575 impl<'tcx> Hash for TyS<'tcx> {
576 fn hash<H: Hasher>(&self, s: &mut H) {
577 (self as *const TyS).hash(s)
581 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
583 impl<'tcx> Encodable for Ty<'tcx> {
584 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
585 cstore::tls::with_encoding_context(s, |ecx, rbml_w| {
586 ecx.encode_ty(rbml_w, *self);
592 impl<'tcx> Decodable for Ty<'tcx> {
593 fn decode<D: Decoder>(d: &mut D) -> Result<Ty<'tcx>, D::Error> {
594 cstore::tls::with_decoding_context(d, |dcx, rbml_r| {
595 Ok(dcx.decode_ty(rbml_r))
601 /// Upvars do not get their own node-id. Instead, we use the pair of
602 /// the original var id (that is, the root variable that is referenced
603 /// by the upvar) and the id of the closure expression.
604 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
607 pub closure_expr_id: NodeId,
610 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
611 pub enum BorrowKind {
612 /// Data must be immutable and is aliasable.
615 /// Data must be immutable but not aliasable. This kind of borrow
616 /// cannot currently be expressed by the user and is used only in
617 /// implicit closure bindings. It is needed when you the closure
618 /// is borrowing or mutating a mutable referent, e.g.:
620 /// let x: &mut isize = ...;
621 /// let y = || *x += 5;
623 /// If we were to try to translate this closure into a more explicit
624 /// form, we'd encounter an error with the code as written:
626 /// struct Env { x: & &mut isize }
627 /// let x: &mut isize = ...;
628 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
629 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
631 /// This is then illegal because you cannot mutate a `&mut` found
632 /// in an aliasable location. To solve, you'd have to translate with
633 /// an `&mut` borrow:
635 /// struct Env { x: & &mut isize }
636 /// let x: &mut isize = ...;
637 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
638 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
640 /// Now the assignment to `**env.x` is legal, but creating a
641 /// mutable pointer to `x` is not because `x` is not mutable. We
642 /// could fix this by declaring `x` as `let mut x`. This is ok in
643 /// user code, if awkward, but extra weird for closures, since the
644 /// borrow is hidden.
646 /// So we introduce a "unique imm" borrow -- the referent is
647 /// immutable, but not aliasable. This solves the problem. For
648 /// simplicity, we don't give users the way to express this
649 /// borrow, it's just used when translating closures.
652 /// Data is mutable and not aliasable.
656 /// Information describing the capture of an upvar. This is computed
657 /// during `typeck`, specifically by `regionck`.
658 #[derive(PartialEq, Clone, Debug, Copy)]
659 pub enum UpvarCapture {
660 /// Upvar is captured by value. This is always true when the
661 /// closure is labeled `move`, but can also be true in other cases
662 /// depending on inference.
665 /// Upvar is captured by reference.
669 #[derive(PartialEq, Clone, Copy)]
670 pub struct UpvarBorrow {
671 /// The kind of borrow: by-ref upvars have access to shared
672 /// immutable borrows, which are not part of the normal language
674 pub kind: BorrowKind,
676 /// Region of the resulting reference.
677 pub region: ty::Region,
680 pub type UpvarCaptureMap = FnvHashMap<UpvarId, UpvarCapture>;
682 #[derive(Copy, Clone)]
683 pub struct ClosureUpvar<'tcx> {
689 #[derive(Clone, Copy, PartialEq)]
690 pub enum IntVarValue {
692 UintType(ast::UintTy),
695 /// Default region to use for the bound of objects that are
696 /// supplied as the value for this type parameter. This is derived
697 /// from `T:'a` annotations appearing in the type definition. If
698 /// this is `None`, then the default is inherited from the
699 /// surrounding context. See RFC #599 for details.
700 #[derive(Copy, Clone)]
701 pub enum ObjectLifetimeDefault {
702 /// Require an explicit annotation. Occurs when multiple
703 /// `T:'a` constraints are found.
706 /// Use the base default, typically 'static, but in a fn body it is a fresh variable
709 /// Use the given region as the default.
714 pub struct TypeParameterDef<'tcx> {
717 pub space: subst::ParamSpace,
719 pub default_def_id: DefId, // for use in error reporing about defaults
720 pub default: Option<Ty<'tcx>>,
721 pub object_lifetime_default: ObjectLifetimeDefault,
725 pub struct RegionParameterDef {
728 pub space: subst::ParamSpace,
730 pub bounds: Vec<ty::Region>,
733 impl RegionParameterDef {
734 pub fn to_early_bound_region(&self) -> ty::Region {
735 ty::ReEarlyBound(ty::EarlyBoundRegion {
741 pub fn to_bound_region(&self) -> ty::BoundRegion {
742 // this is an early bound region, so unaffected by #32330
743 ty::BoundRegion::BrNamed(self.def_id, self.name, Issue32330::WontChange)
747 /// Information about the formal type/lifetime parameters associated
748 /// with an item or method. Analogous to hir::Generics.
749 #[derive(Clone, Debug)]
750 pub struct Generics<'tcx> {
751 pub types: VecPerParamSpace<TypeParameterDef<'tcx>>,
752 pub regions: VecPerParamSpace<RegionParameterDef>,
755 impl<'tcx> Generics<'tcx> {
756 pub fn empty() -> Generics<'tcx> {
758 types: VecPerParamSpace::empty(),
759 regions: VecPerParamSpace::empty(),
763 pub fn is_empty(&self) -> bool {
764 self.types.is_empty() && self.regions.is_empty()
767 pub fn has_type_params(&self, space: subst::ParamSpace) -> bool {
768 !self.types.is_empty_in(space)
771 pub fn has_region_params(&self, space: subst::ParamSpace) -> bool {
772 !self.regions.is_empty_in(space)
776 /// Bounds on generics.
778 pub struct GenericPredicates<'tcx> {
779 pub predicates: VecPerParamSpace<Predicate<'tcx>>,
782 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
783 pub fn empty() -> GenericPredicates<'tcx> {
785 predicates: VecPerParamSpace::empty(),
789 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
790 -> InstantiatedPredicates<'tcx> {
791 InstantiatedPredicates {
792 predicates: self.predicates.subst(tcx, substs),
796 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
797 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
798 -> InstantiatedPredicates<'tcx>
800 InstantiatedPredicates {
801 predicates: self.predicates.map(|pred| {
802 pred.subst_supertrait(tcx, poly_trait_ref)
808 #[derive(Clone, PartialEq, Eq, Hash)]
809 pub enum Predicate<'tcx> {
810 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
811 /// the `Self` type of the trait reference and `A`, `B`, and `C`
812 /// would be the parameters in the `TypeSpace`.
813 Trait(PolyTraitPredicate<'tcx>),
815 /// A predicate created by RFC1592
816 Rfc1592(Box<Predicate<'tcx>>),
818 /// where `T1 == T2`.
819 Equate(PolyEquatePredicate<'tcx>),
822 RegionOutlives(PolyRegionOutlivesPredicate),
825 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
827 /// where <T as TraitRef>::Name == X, approximately.
828 /// See `ProjectionPredicate` struct for details.
829 Projection(PolyProjectionPredicate<'tcx>),
832 WellFormed(Ty<'tcx>),
834 /// trait must be object-safe
837 /// No direct syntax. May be thought of as `where T : FnFoo<...>` for some 'TypeSpace'
838 /// substitutions `...` and T being a closure type. Satisfied (or refuted) once we know the
840 ClosureKind(DefId, ClosureKind),
843 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
844 /// Performs a substitution suitable for going from a
845 /// poly-trait-ref to supertraits that must hold if that
846 /// poly-trait-ref holds. This is slightly different from a normal
847 /// substitution in terms of what happens with bound regions. See
848 /// lengthy comment below for details.
849 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
850 trait_ref: &ty::PolyTraitRef<'tcx>)
851 -> ty::Predicate<'tcx>
853 // The interaction between HRTB and supertraits is not entirely
854 // obvious. Let me walk you (and myself) through an example.
856 // Let's start with an easy case. Consider two traits:
858 // trait Foo<'a> : Bar<'a,'a> { }
859 // trait Bar<'b,'c> { }
861 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
862 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
863 // knew that `Foo<'x>` (for any 'x) then we also know that
864 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
865 // normal substitution.
867 // In terms of why this is sound, the idea is that whenever there
868 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
869 // holds. So if there is an impl of `T:Foo<'a>` that applies to
870 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
873 // Another example to be careful of is this:
875 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
876 // trait Bar1<'b,'c> { }
878 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
879 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
880 // reason is similar to the previous example: any impl of
881 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
882 // basically we would want to collapse the bound lifetimes from
883 // the input (`trait_ref`) and the supertraits.
885 // To achieve this in practice is fairly straightforward. Let's
886 // consider the more complicated scenario:
888 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
889 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
890 // where both `'x` and `'b` would have a DB index of 1.
891 // The substitution from the input trait-ref is therefore going to be
892 // `'a => 'x` (where `'x` has a DB index of 1).
893 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
894 // early-bound parameter and `'b' is a late-bound parameter with a
896 // - If we replace `'a` with `'x` from the input, it too will have
897 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
898 // just as we wanted.
900 // There is only one catch. If we just apply the substitution `'a
901 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
902 // adjust the DB index because we substituting into a binder (it
903 // tries to be so smart...) resulting in `for<'x> for<'b>
904 // Bar1<'x,'b>` (we have no syntax for this, so use your
905 // imagination). Basically the 'x will have DB index of 2 and 'b
906 // will have DB index of 1. Not quite what we want. So we apply
907 // the substitution to the *contents* of the trait reference,
908 // rather than the trait reference itself (put another way, the
909 // substitution code expects equal binding levels in the values
910 // from the substitution and the value being substituted into, and
911 // this trick achieves that).
913 let substs = &trait_ref.0.substs;
915 Predicate::Trait(ty::Binder(ref data)) =>
916 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
917 Predicate::Rfc1592(ref pi) =>
918 Predicate::Rfc1592(Box::new(pi.subst_supertrait(tcx, trait_ref))),
919 Predicate::Equate(ty::Binder(ref data)) =>
920 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
921 Predicate::RegionOutlives(ty::Binder(ref data)) =>
922 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
923 Predicate::TypeOutlives(ty::Binder(ref data)) =>
924 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
925 Predicate::Projection(ty::Binder(ref data)) =>
926 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
927 Predicate::WellFormed(data) =>
928 Predicate::WellFormed(data.subst(tcx, substs)),
929 Predicate::ObjectSafe(trait_def_id) =>
930 Predicate::ObjectSafe(trait_def_id),
931 Predicate::ClosureKind(closure_def_id, kind) =>
932 Predicate::ClosureKind(closure_def_id, kind),
937 #[derive(Clone, PartialEq, Eq, Hash)]
938 pub struct TraitPredicate<'tcx> {
939 pub trait_ref: TraitRef<'tcx>
941 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
943 impl<'tcx> TraitPredicate<'tcx> {
944 pub fn def_id(&self) -> DefId {
945 self.trait_ref.def_id
948 /// Creates the dep-node for selecting/evaluating this trait reference.
949 fn dep_node(&self) -> DepNode<DefId> {
950 // Ideally, the dep-node would just have all the input types
951 // in it. But they are limited to including def-ids. So as an
952 // approximation we include the def-ids for all nominal types
953 // found somewhere. This means that we will e.g. conflate the
954 // dep-nodes for `u32: SomeTrait` and `u64: SomeTrait`, but we
955 // would have distinct dep-nodes for `Vec<u32>: SomeTrait`,
956 // `Rc<u32>: SomeTrait`, and `(Vec<u32>, Rc<u32>): SomeTrait`.
957 // Note that it's always sound to conflate dep-nodes, it just
958 // leads to more recompilation.
959 let def_ids: Vec<_> =
962 .flat_map(|t| t.walk())
963 .filter_map(|t| match t.sty {
964 ty::TyStruct(adt_def, _) |
965 ty::TyEnum(adt_def, _) =>
971 DepNode::TraitSelect(self.def_id(), def_ids)
974 pub fn input_types(&self) -> &[Ty<'tcx>] {
975 self.trait_ref.substs.types.as_slice()
978 pub fn self_ty(&self) -> Ty<'tcx> {
979 self.trait_ref.self_ty()
983 impl<'tcx> PolyTraitPredicate<'tcx> {
984 pub fn def_id(&self) -> DefId {
985 // ok to skip binder since trait def-id does not care about regions
989 pub fn dep_node(&self) -> DepNode<DefId> {
990 // ok to skip binder since depnode does not care about regions
995 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
996 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
997 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
999 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
1000 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
1001 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1002 pub type PolyRegionOutlivesPredicate = PolyOutlivesPredicate<ty::Region, ty::Region>;
1003 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region>;
1005 /// This kind of predicate has no *direct* correspondent in the
1006 /// syntax, but it roughly corresponds to the syntactic forms:
1008 /// 1. `T : TraitRef<..., Item=Type>`
1009 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1011 /// In particular, form #1 is "desugared" to the combination of a
1012 /// normal trait predicate (`T : TraitRef<...>`) and one of these
1013 /// predicates. Form #2 is a broader form in that it also permits
1014 /// equality between arbitrary types. Processing an instance of Form
1015 /// #2 eventually yields one of these `ProjectionPredicate`
1016 /// instances to normalize the LHS.
1017 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
1018 pub struct ProjectionPredicate<'tcx> {
1019 pub projection_ty: ProjectionTy<'tcx>,
1023 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1025 impl<'tcx> PolyProjectionPredicate<'tcx> {
1026 pub fn item_name(&self) -> Name {
1027 self.0.projection_ty.item_name // safe to skip the binder to access a name
1030 pub fn sort_key(&self) -> (DefId, Name) {
1031 self.0.projection_ty.sort_key()
1035 pub trait ToPolyTraitRef<'tcx> {
1036 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1039 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1040 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1041 assert!(!self.has_escaping_regions());
1042 ty::Binder(self.clone())
1046 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1047 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1048 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1052 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
1053 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1054 // Note: unlike with TraitRef::to_poly_trait_ref(),
1055 // self.0.trait_ref is permitted to have escaping regions.
1056 // This is because here `self` has a `Binder` and so does our
1057 // return value, so we are preserving the number of binding
1059 ty::Binder(self.0.projection_ty.trait_ref)
1063 pub trait ToPredicate<'tcx> {
1064 fn to_predicate(&self) -> Predicate<'tcx>;
1067 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1068 fn to_predicate(&self) -> Predicate<'tcx> {
1069 // we're about to add a binder, so let's check that we don't
1070 // accidentally capture anything, or else that might be some
1071 // weird debruijn accounting.
1072 assert!(!self.has_escaping_regions());
1074 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
1075 trait_ref: self.clone()
1080 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1081 fn to_predicate(&self) -> Predicate<'tcx> {
1082 ty::Predicate::Trait(self.to_poly_trait_predicate())
1086 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
1087 fn to_predicate(&self) -> Predicate<'tcx> {
1088 Predicate::Equate(self.clone())
1092 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate {
1093 fn to_predicate(&self) -> Predicate<'tcx> {
1094 Predicate::RegionOutlives(self.clone())
1098 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1099 fn to_predicate(&self) -> Predicate<'tcx> {
1100 Predicate::TypeOutlives(self.clone())
1104 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1105 fn to_predicate(&self) -> Predicate<'tcx> {
1106 Predicate::Projection(self.clone())
1110 impl<'tcx> Predicate<'tcx> {
1111 /// Iterates over the types in this predicate. Note that in all
1112 /// cases this is skipping over a binder, so late-bound regions
1113 /// with depth 0 are bound by the predicate.
1114 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1115 let vec: Vec<_> = match *self {
1116 ty::Predicate::Trait(ref data) => {
1117 data.0.trait_ref.substs.types.as_slice().to_vec()
1119 ty::Predicate::Rfc1592(ref data) => {
1120 return data.walk_tys()
1122 ty::Predicate::Equate(ty::Binder(ref data)) => {
1123 vec![data.0, data.1]
1125 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
1128 ty::Predicate::RegionOutlives(..) => {
1131 ty::Predicate::Projection(ref data) => {
1132 let trait_inputs = data.0.projection_ty.trait_ref.substs.types.as_slice();
1135 .chain(Some(data.0.ty))
1138 ty::Predicate::WellFormed(data) => {
1141 ty::Predicate::ObjectSafe(_trait_def_id) => {
1144 ty::Predicate::ClosureKind(_closure_def_id, _kind) => {
1149 // The only reason to collect into a vector here is that I was
1150 // too lazy to make the full (somewhat complicated) iterator
1151 // type that would be needed here. But I wanted this fn to
1152 // return an iterator conceptually, rather than a `Vec`, so as
1153 // to be closer to `Ty::walk`.
1157 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1159 Predicate::Trait(ref t) => {
1160 Some(t.to_poly_trait_ref())
1162 Predicate::Rfc1592(..) |
1163 Predicate::Projection(..) |
1164 Predicate::Equate(..) |
1165 Predicate::RegionOutlives(..) |
1166 Predicate::WellFormed(..) |
1167 Predicate::ObjectSafe(..) |
1168 Predicate::ClosureKind(..) |
1169 Predicate::TypeOutlives(..) => {
1176 /// Represents the bounds declared on a particular set of type
1177 /// parameters. Should eventually be generalized into a flag list of
1178 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1179 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1180 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1181 /// the `GenericPredicates` are expressed in terms of the bound type
1182 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1183 /// represented a set of bounds for some particular instantiation,
1184 /// meaning that the generic parameters have been substituted with
1189 /// struct Foo<T,U:Bar<T>> { ... }
1191 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1192 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1193 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1194 /// [usize:Bar<isize>]]`.
1196 pub struct InstantiatedPredicates<'tcx> {
1197 pub predicates: VecPerParamSpace<Predicate<'tcx>>,
1200 impl<'tcx> InstantiatedPredicates<'tcx> {
1201 pub fn empty() -> InstantiatedPredicates<'tcx> {
1202 InstantiatedPredicates { predicates: VecPerParamSpace::empty() }
1205 pub fn is_empty(&self) -> bool {
1206 self.predicates.is_empty()
1210 impl<'tcx> TraitRef<'tcx> {
1211 pub fn new(def_id: DefId, substs: &'tcx Substs<'tcx>) -> TraitRef<'tcx> {
1212 TraitRef { def_id: def_id, substs: substs }
1215 pub fn self_ty(&self) -> Ty<'tcx> {
1216 self.substs.self_ty().unwrap()
1219 pub fn input_types(&self) -> &[Ty<'tcx>] {
1220 // Select only the "input types" from a trait-reference. For
1221 // now this is all the types that appear in the
1222 // trait-reference, but it should eventually exclude
1223 // associated types.
1224 self.substs.types.as_slice()
1228 /// When type checking, we use the `ParameterEnvironment` to track
1229 /// details about the type/lifetime parameters that are in scope.
1230 /// It primarily stores the bounds information.
1232 /// Note: This information might seem to be redundant with the data in
1233 /// `tcx.ty_param_defs`, but it is not. That table contains the
1234 /// parameter definitions from an "outside" perspective, but this
1235 /// struct will contain the bounds for a parameter as seen from inside
1236 /// the function body. Currently the only real distinction is that
1237 /// bound lifetime parameters are replaced with free ones, but in the
1238 /// future I hope to refine the representation of types so as to make
1239 /// more distinctions clearer.
1241 pub struct ParameterEnvironment<'tcx> {
1242 /// See `construct_free_substs` for details.
1243 pub free_substs: &'tcx Substs<'tcx>,
1245 /// Each type parameter has an implicit region bound that
1246 /// indicates it must outlive at least the function body (the user
1247 /// may specify stronger requirements). This field indicates the
1248 /// region of the callee.
1249 pub implicit_region_bound: ty::Region,
1251 /// Obligations that the caller must satisfy. This is basically
1252 /// the set of bounds on the in-scope type parameters, translated
1253 /// into Obligations, and elaborated and normalized.
1254 pub caller_bounds: Vec<ty::Predicate<'tcx>>,
1256 /// Scope that is attached to free regions for this scope. This
1257 /// is usually the id of the fn body, but for more abstract scopes
1258 /// like structs we often use the node-id of the struct.
1260 /// FIXME(#3696). It would be nice to refactor so that free
1261 /// regions don't have this implicit scope and instead introduce
1262 /// relationships in the environment.
1263 pub free_id_outlive: CodeExtent,
1266 impl<'a, 'tcx> ParameterEnvironment<'tcx> {
1267 pub fn with_caller_bounds(&self,
1268 caller_bounds: Vec<ty::Predicate<'tcx>>)
1269 -> ParameterEnvironment<'tcx>
1271 ParameterEnvironment {
1272 free_substs: self.free_substs,
1273 implicit_region_bound: self.implicit_region_bound,
1274 caller_bounds: caller_bounds,
1275 free_id_outlive: self.free_id_outlive,
1279 /// Construct a parameter environment given an item, impl item, or trait item
1280 pub fn for_item(tcx: TyCtxt<'a, 'tcx, 'tcx>, id: NodeId)
1281 -> ParameterEnvironment<'tcx> {
1282 match tcx.map.find(id) {
1283 Some(ast_map::NodeImplItem(ref impl_item)) => {
1284 match impl_item.node {
1285 hir::ImplItemKind::Type(_) | hir::ImplItemKind::Const(_, _) => {
1286 // associated types don't have their own entry (for some reason),
1287 // so for now just grab environment for the impl
1288 let impl_id = tcx.map.get_parent(id);
1289 let impl_def_id = tcx.map.local_def_id(impl_id);
1290 let scheme = tcx.lookup_item_type(impl_def_id);
1291 let predicates = tcx.lookup_predicates(impl_def_id);
1292 tcx.construct_parameter_environment(impl_item.span,
1295 tcx.region_maps.item_extent(id))
1297 hir::ImplItemKind::Method(_, ref body) => {
1298 let method_def_id = tcx.map.local_def_id(id);
1299 match tcx.impl_or_trait_item(method_def_id) {
1300 MethodTraitItem(ref method_ty) => {
1301 let method_generics = &method_ty.generics;
1302 let method_bounds = &method_ty.predicates;
1303 tcx.construct_parameter_environment(
1307 tcx.region_maps.call_site_extent(id, body.id))
1310 bug!("ParameterEnvironment::for_item(): \
1311 got non-method item from impl method?!")
1317 Some(ast_map::NodeTraitItem(trait_item)) => {
1318 match trait_item.node {
1319 hir::TypeTraitItem(..) | hir::ConstTraitItem(..) => {
1320 // associated types don't have their own entry (for some reason),
1321 // so for now just grab environment for the trait
1322 let trait_id = tcx.map.get_parent(id);
1323 let trait_def_id = tcx.map.local_def_id(trait_id);
1324 let trait_def = tcx.lookup_trait_def(trait_def_id);
1325 let predicates = tcx.lookup_predicates(trait_def_id);
1326 tcx.construct_parameter_environment(trait_item.span,
1327 &trait_def.generics,
1329 tcx.region_maps.item_extent(id))
1331 hir::MethodTraitItem(_, ref body) => {
1332 // Use call-site for extent (unless this is a
1333 // trait method with no default; then fallback
1334 // to the method id).
1335 let method_def_id = tcx.map.local_def_id(id);
1336 match tcx.impl_or_trait_item(method_def_id) {
1337 MethodTraitItem(ref method_ty) => {
1338 let method_generics = &method_ty.generics;
1339 let method_bounds = &method_ty.predicates;
1340 let extent = if let Some(ref body) = *body {
1341 // default impl: use call_site extent as free_id_outlive bound.
1342 tcx.region_maps.call_site_extent(id, body.id)
1344 // no default impl: use item extent as free_id_outlive bound.
1345 tcx.region_maps.item_extent(id)
1347 tcx.construct_parameter_environment(
1354 bug!("ParameterEnvironment::for_item(): \
1355 got non-method item from provided \
1362 Some(ast_map::NodeItem(item)) => {
1364 hir::ItemFn(_, _, _, _, _, ref body) => {
1365 // We assume this is a function.
1366 let fn_def_id = tcx.map.local_def_id(id);
1367 let fn_scheme = tcx.lookup_item_type(fn_def_id);
1368 let fn_predicates = tcx.lookup_predicates(fn_def_id);
1370 tcx.construct_parameter_environment(
1372 &fn_scheme.generics,
1374 tcx.region_maps.call_site_extent(id, body.id))
1377 hir::ItemStruct(..) |
1380 hir::ItemConst(..) |
1381 hir::ItemStatic(..) => {
1382 let def_id = tcx.map.local_def_id(id);
1383 let scheme = tcx.lookup_item_type(def_id);
1384 let predicates = tcx.lookup_predicates(def_id);
1385 tcx.construct_parameter_environment(item.span,
1388 tcx.region_maps.item_extent(id))
1390 hir::ItemTrait(..) => {
1391 let def_id = tcx.map.local_def_id(id);
1392 let trait_def = tcx.lookup_trait_def(def_id);
1393 let predicates = tcx.lookup_predicates(def_id);
1394 tcx.construct_parameter_environment(item.span,
1395 &trait_def.generics,
1397 tcx.region_maps.item_extent(id))
1400 span_bug!(item.span,
1401 "ParameterEnvironment::for_item():
1402 can't create a parameter \
1403 environment for this kind of item")
1407 Some(ast_map::NodeExpr(..)) => {
1408 // This is a convenience to allow closures to work.
1409 ParameterEnvironment::for_item(tcx, tcx.map.get_parent(id))
1411 Some(ast_map::NodeForeignItem(item)) => {
1412 let def_id = tcx.map.local_def_id(id);
1413 let scheme = tcx.lookup_item_type(def_id);
1414 let predicates = tcx.lookup_predicates(def_id);
1415 tcx.construct_parameter_environment(item.span,
1421 bug!("ParameterEnvironment::from_item(): \
1422 `{}` is not an item",
1423 tcx.map.node_to_string(id))
1429 /// A "type scheme", in ML terminology, is a type combined with some
1430 /// set of generic types that the type is, well, generic over. In Rust
1431 /// terms, it is the "type" of a fn item or struct -- this type will
1432 /// include various generic parameters that must be substituted when
1433 /// the item/struct is referenced. That is called converting the type
1434 /// scheme to a monotype.
1436 /// - `generics`: the set of type parameters and their bounds
1437 /// - `ty`: the base types, which may reference the parameters defined
1440 /// Note that TypeSchemes are also sometimes called "polytypes" (and
1441 /// in fact this struct used to carry that name, so you may find some
1442 /// stray references in a comment or something). We try to reserve the
1443 /// "poly" prefix to refer to higher-ranked things, as in
1446 /// Note that each item also comes with predicates, see
1447 /// `lookup_predicates`.
1448 #[derive(Clone, Debug)]
1449 pub struct TypeScheme<'tcx> {
1450 pub generics: Generics<'tcx>,
1455 flags AdtFlags: u32 {
1456 const NO_ADT_FLAGS = 0,
1457 const IS_ENUM = 1 << 0,
1458 const IS_DTORCK = 1 << 1, // is this a dtorck type?
1459 const IS_DTORCK_VALID = 1 << 2,
1460 const IS_PHANTOM_DATA = 1 << 3,
1461 const IS_SIMD = 1 << 4,
1462 const IS_FUNDAMENTAL = 1 << 5,
1463 const IS_NO_DROP_FLAG = 1 << 6,
1467 pub type AdtDef<'tcx> = &'tcx AdtDefData<'tcx, 'static>;
1468 pub type VariantDef<'tcx> = &'tcx VariantDefData<'tcx, 'static>;
1469 pub type FieldDef<'tcx> = &'tcx FieldDefData<'tcx, 'static>;
1471 // See comment on AdtDefData for explanation
1472 pub type AdtDefMaster<'tcx> = &'tcx AdtDefData<'tcx, 'tcx>;
1473 pub type VariantDefMaster<'tcx> = &'tcx VariantDefData<'tcx, 'tcx>;
1474 pub type FieldDefMaster<'tcx> = &'tcx FieldDefData<'tcx, 'tcx>;
1476 pub struct VariantDefData<'tcx, 'container: 'tcx> {
1477 /// The variant's DefId. If this is a tuple-like struct,
1478 /// this is the DefId of the struct's ctor.
1480 pub name: Name, // struct's name if this is a struct
1482 pub fields: Vec<FieldDefData<'tcx, 'container>>,
1483 pub kind: VariantKind,
1486 pub struct FieldDefData<'tcx, 'container: 'tcx> {
1487 /// The field's DefId. NOTE: the fields of tuple-like enum variants
1488 /// are not real items, and don't have entries in tcache etc.
1491 pub vis: Visibility,
1492 /// TyIVar is used here to allow for variance (see the doc at
1495 /// Note: direct accesses to `ty` must also add dep edges.
1496 ty: ivar::TyIVar<'tcx, 'container>
1499 /// The definition of an abstract data type - a struct or enum.
1501 /// These are all interned (by intern_adt_def) into the adt_defs
1504 /// Because of the possibility of nested tcx-s, this type
1505 /// needs 2 lifetimes: the traditional variant lifetime ('tcx)
1506 /// bounding the lifetime of the inner types is of course necessary.
1507 /// However, it is not sufficient - types from a child tcx must
1508 /// not be leaked into the master tcx by being stored in an AdtDefData.
1510 /// The 'container lifetime ensures that by outliving the container
1511 /// tcx and preventing shorter-lived types from being inserted. When
1512 /// write access is not needed, the 'container lifetime can be
1513 /// erased to 'static, which can be done by the AdtDef wrapper.
1514 pub struct AdtDefData<'tcx, 'container: 'tcx> {
1516 pub variants: Vec<VariantDefData<'tcx, 'container>>,
1517 destructor: Cell<Option<DefId>>,
1518 flags: Cell<AdtFlags>,
1519 sized_constraint: ivar::TyIVar<'tcx, 'container>,
1522 impl<'tcx, 'container> PartialEq for AdtDefData<'tcx, 'container> {
1523 // AdtDefData are always interned and this is part of TyS equality
1525 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1528 impl<'tcx, 'container> Eq for AdtDefData<'tcx, 'container> {}
1530 impl<'tcx, 'container> Hash for AdtDefData<'tcx, 'container> {
1532 fn hash<H: Hasher>(&self, s: &mut H) {
1533 (self as *const AdtDefData).hash(s)
1537 impl<'tcx> Encodable for AdtDef<'tcx> {
1538 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1543 impl<'tcx> Decodable for AdtDef<'tcx> {
1544 fn decode<D: Decoder>(d: &mut D) -> Result<AdtDef<'tcx>, D::Error> {
1545 let def_id: DefId = Decodable::decode(d)?;
1547 cstore::tls::with_decoding_context(d, |dcx, _| {
1548 let def_id = dcx.translate_def_id(def_id);
1549 Ok(dcx.tcx().lookup_adt_def(def_id))
1555 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1556 pub enum AdtKind { Struct, Enum }
1558 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1559 pub enum VariantKind { Struct, Tuple, Unit }
1562 pub fn from_variant_data(vdata: &hir::VariantData) -> Self {
1564 hir::VariantData::Struct(..) => VariantKind::Struct,
1565 hir::VariantData::Tuple(..) => VariantKind::Tuple,
1566 hir::VariantData::Unit(..) => VariantKind::Unit,
1571 impl<'a, 'gcx, 'tcx, 'container> AdtDefData<'gcx, 'container> {
1572 fn new(tcx: TyCtxt<'a, 'gcx, 'tcx>,
1575 variants: Vec<VariantDefData<'gcx, 'container>>) -> Self {
1576 let mut flags = AdtFlags::NO_ADT_FLAGS;
1577 let attrs = tcx.get_attrs(did);
1578 if attr::contains_name(&attrs, "fundamental") {
1579 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1581 if attr::contains_name(&attrs, "unsafe_no_drop_flag") {
1582 flags = flags | AdtFlags::IS_NO_DROP_FLAG;
1584 if tcx.lookup_simd(did) {
1585 flags = flags | AdtFlags::IS_SIMD;
1587 if Some(did) == tcx.lang_items.phantom_data() {
1588 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1590 if let AdtKind::Enum = kind {
1591 flags = flags | AdtFlags::IS_ENUM;
1596 flags: Cell::new(flags),
1597 destructor: Cell::new(None),
1598 sized_constraint: ivar::TyIVar::new(),
1602 fn calculate_dtorck(&'gcx self, tcx: TyCtxt) {
1603 if tcx.is_adt_dtorck(self) {
1604 self.flags.set(self.flags.get() | AdtFlags::IS_DTORCK);
1606 self.flags.set(self.flags.get() | AdtFlags::IS_DTORCK_VALID)
1609 /// Returns the kind of the ADT - Struct or Enum.
1611 pub fn adt_kind(&self) -> AdtKind {
1612 if self.flags.get().intersects(AdtFlags::IS_ENUM) {
1619 /// Returns whether this is a dtorck type. If this returns
1620 /// true, this type being safe for destruction requires it to be
1621 /// alive; Otherwise, only the contents are required to be.
1623 pub fn is_dtorck(&'gcx self, tcx: TyCtxt) -> bool {
1624 if !self.flags.get().intersects(AdtFlags::IS_DTORCK_VALID) {
1625 self.calculate_dtorck(tcx)
1627 self.flags.get().intersects(AdtFlags::IS_DTORCK)
1630 /// Returns whether this type is #[fundamental] for the purposes
1631 /// of coherence checking.
1633 pub fn is_fundamental(&self) -> bool {
1634 self.flags.get().intersects(AdtFlags::IS_FUNDAMENTAL)
1638 pub fn is_simd(&self) -> bool {
1639 self.flags.get().intersects(AdtFlags::IS_SIMD)
1642 /// Returns true if this is PhantomData<T>.
1644 pub fn is_phantom_data(&self) -> bool {
1645 self.flags.get().intersects(AdtFlags::IS_PHANTOM_DATA)
1648 /// Returns whether this type has a destructor.
1649 pub fn has_dtor(&self) -> bool {
1650 match self.dtor_kind() {
1652 TraitDtor(..) => true
1656 /// Asserts this is a struct and returns the struct's unique
1658 pub fn struct_variant(&self) -> &VariantDefData<'gcx, 'container> {
1659 assert_eq!(self.adt_kind(), AdtKind::Struct);
1664 pub fn type_scheme(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> TypeScheme<'gcx> {
1665 tcx.lookup_item_type(self.did)
1669 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
1670 tcx.lookup_predicates(self.did)
1673 /// Returns an iterator over all fields contained
1676 pub fn all_fields(&self) ->
1678 slice::Iter<VariantDefData<'gcx, 'container>>,
1679 slice::Iter<FieldDefData<'gcx, 'container>>,
1680 for<'s> fn(&'s VariantDefData<'gcx, 'container>)
1681 -> slice::Iter<'s, FieldDefData<'gcx, 'container>>
1683 self.variants.iter().flat_map(VariantDefData::fields_iter)
1687 pub fn is_empty(&self) -> bool {
1688 self.variants.is_empty()
1692 pub fn is_univariant(&self) -> bool {
1693 self.variants.len() == 1
1696 pub fn is_payloadfree(&self) -> bool {
1697 !self.variants.is_empty() &&
1698 self.variants.iter().all(|v| v.fields.is_empty())
1701 pub fn variant_with_id(&self, vid: DefId) -> &VariantDefData<'gcx, 'container> {
1704 .find(|v| v.did == vid)
1705 .expect("variant_with_id: unknown variant")
1708 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1711 .position(|v| v.did == vid)
1712 .expect("variant_index_with_id: unknown variant")
1715 pub fn variant_of_def(&self, def: Def) -> &VariantDefData<'gcx, 'container> {
1717 Def::Variant(_, vid) => self.variant_with_id(vid),
1718 Def::Struct(..) | Def::TyAlias(..) | Def::AssociatedTy(..) => self.struct_variant(),
1719 _ => bug!("unexpected def {:?} in variant_of_def", def)
1723 pub fn destructor(&self) -> Option<DefId> {
1724 self.destructor.get()
1727 pub fn set_destructor(&self, dtor: DefId) {
1728 self.destructor.set(Some(dtor));
1731 pub fn dtor_kind(&self) -> DtorKind {
1732 match self.destructor.get() {
1734 TraitDtor(!self.flags.get().intersects(AdtFlags::IS_NO_DROP_FLAG))
1741 impl<'a, 'gcx, 'tcx, 'container> AdtDefData<'tcx, 'container> {
1742 /// Returns a simpler type such that `Self: Sized` if and only
1743 /// if that type is Sized, or `TyErr` if this type is recursive.
1745 /// HACK: instead of returning a list of types, this function can
1746 /// return a tuple. In that case, the result is Sized only if
1747 /// all elements of the tuple are Sized.
1749 /// This is generally the `struct_tail` if this is a struct, or a
1750 /// tuple of them if this is an enum.
1752 /// Oddly enough, checking that the sized-constraint is Sized is
1753 /// actually more expressive than checking all members:
1754 /// the Sized trait is inductive, so an associated type that references
1755 /// Self would prevent its containing ADT from being Sized.
1757 /// Due to normalization being eager, this applies even if
1758 /// the associated type is behind a pointer, e.g. issue #31299.
1759 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Ty<'tcx> {
1760 let dep_node = DepNode::SizedConstraint(self.did);
1761 match self.sized_constraint.get(dep_node) {
1763 let global_tcx = tcx.global_tcx();
1764 let this = global_tcx.lookup_adt_def_master(self.did);
1765 this.calculate_sized_constraint_inner(global_tcx, &mut Vec::new());
1766 self.sized_constraint(tcx)
1773 impl<'a, 'tcx> AdtDefData<'tcx, 'tcx> {
1774 /// Calculates the Sized-constraint.
1776 /// As the Sized-constraint of enums can be a *set* of types,
1777 /// the Sized-constraint may need to be a set also. Because introducing
1778 /// a new type of IVar is currently a complex affair, the Sized-constraint
1781 /// In fact, there are only a few options for the constraint:
1782 /// - `bool`, if the type is always Sized
1783 /// - an obviously-unsized type
1784 /// - a type parameter or projection whose Sizedness can't be known
1785 /// - a tuple of type parameters or projections, if there are multiple
1787 /// - a TyError, if a type contained itself. The representability
1788 /// check should catch this case.
1789 fn calculate_sized_constraint_inner(&'tcx self, tcx: TyCtxt<'a, 'tcx, 'tcx>,
1790 stack: &mut Vec<AdtDefMaster<'tcx>>)
1793 let dep_node = || DepNode::SizedConstraint(self.did);
1794 if self.sized_constraint.get(dep_node()).is_some() {
1798 if stack.contains(&self) {
1799 debug!("calculate_sized_constraint: {:?} is recursive", self);
1800 // This should be reported as an error by `check_representable`.
1802 // Consider the type as Sized in the meanwhile to avoid
1804 self.sized_constraint.fulfill(dep_node(), tcx.types.err);
1811 self.variants.iter().flat_map(|v| {
1814 self.sized_constraint_for_ty(tcx, stack, f.unsubst_ty())
1817 let self_ = stack.pop().unwrap();
1818 assert_eq!(self_, self);
1820 let ty = match tys.len() {
1821 _ if tys.references_error() => tcx.types.err,
1822 0 => tcx.types.bool,
1824 _ => tcx.mk_tup(tys)
1827 match self.sized_constraint.get(dep_node()) {
1829 debug!("calculate_sized_constraint: {:?} recurred", self);
1830 assert_eq!(old_ty, tcx.types.err)
1833 debug!("calculate_sized_constraint: {:?} => {:?}", self, ty);
1834 self.sized_constraint.fulfill(dep_node(), ty)
1839 fn sized_constraint_for_ty(
1841 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1842 stack: &mut Vec<AdtDefMaster<'tcx>>,
1844 ) -> Vec<Ty<'tcx>> {
1845 let result = match ty.sty {
1846 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
1847 TyBox(..) | TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
1848 TyArray(..) | TyClosure(..) => {
1852 TyStr | TyTrait(..) | TySlice(_) | TyError => {
1853 // these are never sized - return the target type
1857 TyTuple(ref tys) => {
1858 // FIXME(#33242) we only need to constrain the last field
1859 tys.iter().flat_map(|ty| {
1860 self.sized_constraint_for_ty(tcx, stack, ty)
1864 TyEnum(adt, substs) | TyStruct(adt, substs) => {
1866 let adt = tcx.lookup_adt_def_master(adt.did);
1867 adt.calculate_sized_constraint_inner(tcx, stack);
1869 adt.sized_constraint
1870 .unwrap(DepNode::SizedConstraint(adt.did))
1871 .subst(tcx, substs);
1872 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
1874 if let ty::TyTuple(ref tys) = adt_ty.sty {
1875 tys.iter().flat_map(|ty| {
1876 self.sized_constraint_for_ty(tcx, stack, ty)
1879 self.sized_constraint_for_ty(tcx, stack, adt_ty)
1883 TyProjection(..) => {
1884 // must calculate explicitly.
1885 // FIXME: consider special-casing always-Sized projections
1890 // perf hack: if there is a `T: Sized` bound, then
1891 // we know that `T` is Sized and do not need to check
1894 let sized_trait = match tcx.lang_items.sized_trait() {
1896 _ => return vec![ty]
1898 let sized_predicate = Binder(TraitRef {
1899 def_id: sized_trait,
1900 substs: tcx.mk_substs(Substs::new_trait(
1904 let predicates = tcx.lookup_predicates(self.did).predicates;
1905 if predicates.into_iter().any(|p| p == sized_predicate) {
1913 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
1917 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
1922 impl<'tcx, 'container> VariantDefData<'tcx, 'container> {
1924 fn fields_iter(&self) -> slice::Iter<FieldDefData<'tcx, 'container>> {
1929 pub fn find_field_named(&self,
1931 -> Option<&FieldDefData<'tcx, 'container>> {
1932 self.fields.iter().find(|f| f.name == name)
1936 pub fn index_of_field_named(&self,
1939 self.fields.iter().position(|f| f.name == name)
1943 pub fn field_named(&self, name: ast::Name) -> &FieldDefData<'tcx, 'container> {
1944 self.find_field_named(name).unwrap()
1948 impl<'a, 'gcx, 'tcx, 'container> FieldDefData<'tcx, 'container> {
1949 pub fn new(did: DefId,
1951 vis: Visibility) -> Self {
1956 ty: ivar::TyIVar::new()
1960 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1961 self.unsubst_ty().subst(tcx, subst)
1964 pub fn unsubst_ty(&self) -> Ty<'tcx> {
1965 self.ty.unwrap(DepNode::FieldTy(self.did))
1968 pub fn fulfill_ty(&self, ty: Ty<'container>) {
1969 self.ty.fulfill(DepNode::FieldTy(self.did), ty);
1973 /// Records the substitutions used to translate the polytype for an
1974 /// item into the monotype of an item reference.
1976 pub struct ItemSubsts<'tcx> {
1977 pub substs: &'tcx Substs<'tcx>,
1980 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1981 pub enum ClosureKind {
1982 // Warning: Ordering is significant here! The ordering is chosen
1983 // because the trait Fn is a subtrait of FnMut and so in turn, and
1984 // hence we order it so that Fn < FnMut < FnOnce.
1990 impl<'a, 'tcx> ClosureKind {
1991 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
1992 let result = match *self {
1993 ClosureKind::Fn => tcx.lang_items.require(FnTraitLangItem),
1994 ClosureKind::FnMut => {
1995 tcx.lang_items.require(FnMutTraitLangItem)
1997 ClosureKind::FnOnce => {
1998 tcx.lang_items.require(FnOnceTraitLangItem)
2002 Ok(trait_did) => trait_did,
2003 Err(err) => tcx.sess.fatal(&err[..]),
2007 /// True if this a type that impls this closure kind
2008 /// must also implement `other`.
2009 pub fn extends(self, other: ty::ClosureKind) -> bool {
2010 match (self, other) {
2011 (ClosureKind::Fn, ClosureKind::Fn) => true,
2012 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2013 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2014 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2015 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2016 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2022 impl<'tcx> TyS<'tcx> {
2023 /// Iterator that walks `self` and any types reachable from
2024 /// `self`, in depth-first order. Note that just walks the types
2025 /// that appear in `self`, it does not descend into the fields of
2026 /// structs or variants. For example:
2029 /// isize => { isize }
2030 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2031 /// [isize] => { [isize], isize }
2033 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2034 TypeWalker::new(self)
2037 /// Iterator that walks the immediate children of `self`. Hence
2038 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2039 /// (but not `i32`, like `walk`).
2040 pub fn walk_shallow(&'tcx self) -> IntoIter<Ty<'tcx>> {
2041 walk::walk_shallow(self)
2044 /// Walks `ty` and any types appearing within `ty`, invoking the
2045 /// callback `f` on each type. If the callback returns false, then the
2046 /// children of the current type are ignored.
2048 /// Note: prefer `ty.walk()` where possible.
2049 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2050 where F : FnMut(Ty<'tcx>) -> bool
2052 let mut walker = self.walk();
2053 while let Some(ty) = walker.next() {
2055 walker.skip_current_subtree();
2061 impl<'tcx> ItemSubsts<'tcx> {
2062 pub fn is_noop(&self) -> bool {
2063 self.substs.is_noop()
2067 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
2068 pub enum LvaluePreference {
2073 impl LvaluePreference {
2074 pub fn from_mutbl(m: hir::Mutability) -> Self {
2076 hir::MutMutable => PreferMutLvalue,
2077 hir::MutImmutable => NoPreference,
2082 /// Helper for looking things up in the various maps that are populated during
2083 /// typeck::collect (e.g., `tcx.impl_or_trait_items`, `tcx.tcache`, etc). All of
2084 /// these share the pattern that if the id is local, it should have been loaded
2085 /// into the map by the `typeck::collect` phase. If the def-id is external,
2086 /// then we have to go consult the crate loading code (and cache the result for
2088 fn lookup_locally_or_in_crate_store<M, F>(descr: &str,
2093 M: MemoizationMap<Key=DefId>,
2094 F: FnOnce() -> M::Value,
2096 map.memoize(def_id, || {
2097 if def_id.is_local() {
2098 bug!("No def'n found for {:?} in tcx.{}", def_id, descr);
2105 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2107 hir::MutMutable => MutBorrow,
2108 hir::MutImmutable => ImmBorrow,
2112 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2113 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2114 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2116 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2118 MutBorrow => hir::MutMutable,
2119 ImmBorrow => hir::MutImmutable,
2121 // We have no type corresponding to a unique imm borrow, so
2122 // use `&mut`. It gives all the capabilities of an `&uniq`
2123 // and hence is a safe "over approximation".
2124 UniqueImmBorrow => hir::MutMutable,
2128 pub fn to_user_str(&self) -> &'static str {
2130 MutBorrow => "mutable",
2131 ImmBorrow => "immutable",
2132 UniqueImmBorrow => "uniquely immutable",
2137 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2138 pub fn node_id_to_type(self, id: NodeId) -> Ty<'gcx> {
2139 match self.node_id_to_type_opt(id) {
2141 None => bug!("node_id_to_type: no type for node `{}`",
2142 self.map.node_to_string(id))
2146 pub fn node_id_to_type_opt(self, id: NodeId) -> Option<Ty<'gcx>> {
2147 self.tables.borrow().node_types.get(&id).cloned()
2150 pub fn node_id_item_substs(self, id: NodeId) -> ItemSubsts<'gcx> {
2151 match self.tables.borrow().item_substs.get(&id) {
2152 None => ItemSubsts {
2153 substs: self.global_tcx().mk_substs(Substs::empty())
2155 Some(ts) => ts.clone(),
2159 // Returns the type of a pattern as a monotype. Like @expr_ty, this function
2160 // doesn't provide type parameter substitutions.
2161 pub fn pat_ty(self, pat: &hir::Pat) -> Ty<'gcx> {
2162 self.node_id_to_type(pat.id)
2164 pub fn pat_ty_opt(self, pat: &hir::Pat) -> Option<Ty<'gcx>> {
2165 self.node_id_to_type_opt(pat.id)
2168 // Returns the type of an expression as a monotype.
2170 // NB (1): This is the PRE-ADJUSTMENT TYPE for the expression. That is, in
2171 // some cases, we insert `AutoAdjustment` annotations such as auto-deref or
2172 // auto-ref. The type returned by this function does not consider such
2173 // adjustments. See `expr_ty_adjusted()` instead.
2175 // NB (2): This type doesn't provide type parameter substitutions; e.g. if you
2176 // ask for the type of "id" in "id(3)", it will return "fn(&isize) -> isize"
2177 // instead of "fn(ty) -> T with T = isize".
2178 pub fn expr_ty(self, expr: &hir::Expr) -> Ty<'gcx> {
2179 self.node_id_to_type(expr.id)
2182 pub fn expr_ty_opt(self, expr: &hir::Expr) -> Option<Ty<'gcx>> {
2183 self.node_id_to_type_opt(expr.id)
2186 /// Returns the type of `expr`, considering any `AutoAdjustment`
2187 /// entry recorded for that expression.
2189 /// It would almost certainly be better to store the adjusted ty in with
2190 /// the `AutoAdjustment`, but I opted not to do this because it would
2191 /// require serializing and deserializing the type and, although that's not
2192 /// hard to do, I just hate that code so much I didn't want to touch it
2193 /// unless it was to fix it properly, which seemed a distraction from the
2194 /// thread at hand! -nmatsakis
2195 pub fn expr_ty_adjusted(self, expr: &hir::Expr) -> Ty<'gcx> {
2197 .adjust(self.global_tcx(), expr.span, expr.id,
2198 self.tables.borrow().adjustments.get(&expr.id),
2200 self.tables.borrow().method_map.get(&method_call).map(|method| method.ty)
2204 pub fn expr_ty_adjusted_opt(self, expr: &hir::Expr) -> Option<Ty<'gcx>> {
2205 self.expr_ty_opt(expr).map(|t| t.adjust(self.global_tcx(),
2208 self.tables.borrow().adjustments.get(&expr.id),
2210 self.tables.borrow().method_map.get(&method_call).map(|method| method.ty)
2214 pub fn expr_span(self, id: NodeId) -> Span {
2215 match self.map.find(id) {
2216 Some(ast_map::NodeExpr(e)) => {
2220 bug!("Node id {} is not an expr: {:?}", id, f);
2223 bug!("Node id {} is not present in the node map", id);
2228 pub fn local_var_name_str(self, id: NodeId) -> InternedString {
2229 match self.map.find(id) {
2230 Some(ast_map::NodeLocal(pat)) => {
2232 PatKind::Binding(_, ref path1, _) => path1.node.as_str(),
2234 bug!("Variable id {} maps to {:?}, not local", id, pat);
2238 r => bug!("Variable id {} maps to {:?}, not local", id, r),
2242 pub fn expr_is_lval(self, expr: &hir::Expr) -> bool {
2244 hir::ExprPath(..) => {
2245 // This function can be used during type checking when not all paths are
2246 // fully resolved. Partially resolved paths in expressions can only legally
2247 // refer to associated items which are always rvalues.
2248 match self.expect_resolution(expr.id).base_def {
2249 Def::Local(..) | Def::Upvar(..) | Def::Static(..) | Def::Err => true,
2254 hir::ExprType(ref e, _) => {
2255 self.expr_is_lval(e)
2258 hir::ExprUnary(hir::UnDeref, _) |
2259 hir::ExprField(..) |
2260 hir::ExprTupField(..) |
2261 hir::ExprIndex(..) => {
2266 hir::ExprMethodCall(..) |
2267 hir::ExprStruct(..) |
2270 hir::ExprMatch(..) |
2271 hir::ExprClosure(..) |
2272 hir::ExprBlock(..) |
2273 hir::ExprRepeat(..) |
2275 hir::ExprBreak(..) |
2276 hir::ExprAgain(..) |
2278 hir::ExprWhile(..) |
2280 hir::ExprAssign(..) |
2281 hir::ExprInlineAsm(..) |
2282 hir::ExprAssignOp(..) |
2284 hir::ExprUnary(..) |
2286 hir::ExprAddrOf(..) |
2287 hir::ExprBinary(..) |
2288 hir::ExprCast(..) => {
2294 pub fn provided_trait_methods(self, id: DefId) -> Vec<Rc<Method<'gcx>>> {
2295 if let Some(id) = self.map.as_local_node_id(id) {
2296 if let ItemTrait(_, _, _, ref ms) = self.map.expect_item(id).node {
2297 ms.iter().filter_map(|ti| {
2298 if let hir::MethodTraitItem(_, Some(_)) = ti.node {
2299 match self.impl_or_trait_item(self.map.local_def_id(ti.id)) {
2300 MethodTraitItem(m) => Some(m),
2302 bug!("provided_trait_methods(): \
2303 non-method item found from \
2304 looking up provided method?!")
2312 bug!("provided_trait_methods: `{:?}` is not a trait", id)
2315 self.sess.cstore.provided_trait_methods(self.global_tcx(), id)
2319 pub fn associated_consts(self, id: DefId) -> Vec<Rc<AssociatedConst<'gcx>>> {
2320 if let Some(id) = self.map.as_local_node_id(id) {
2321 match self.map.expect_item(id).node {
2322 ItemTrait(_, _, _, ref tis) => {
2323 tis.iter().filter_map(|ti| {
2324 if let hir::ConstTraitItem(_, _) = ti.node {
2325 match self.impl_or_trait_item(self.map.local_def_id(ti.id)) {
2326 ConstTraitItem(ac) => Some(ac),
2328 bug!("associated_consts(): \
2329 non-const item found from \
2330 looking up a constant?!")
2338 ItemImpl(_, _, _, _, _, ref iis) => {
2339 iis.iter().filter_map(|ii| {
2340 if let hir::ImplItemKind::Const(_, _) = ii.node {
2341 match self.impl_or_trait_item(self.map.local_def_id(ii.id)) {
2342 ConstTraitItem(ac) => Some(ac),
2344 bug!("associated_consts(): \
2345 non-const item found from \
2346 looking up a constant?!")
2355 bug!("associated_consts: `{:?}` is not a trait or impl", id)
2359 self.sess.cstore.associated_consts(self.global_tcx(), id)
2363 pub fn trait_impl_polarity(self, id: DefId) -> Option<hir::ImplPolarity> {
2364 if let Some(id) = self.map.as_local_node_id(id) {
2365 match self.map.find(id) {
2366 Some(ast_map::NodeItem(item)) => {
2368 hir::ItemImpl(_, polarity, _, _, _, _) => Some(polarity),
2375 self.sess.cstore.impl_polarity(id)
2379 pub fn custom_coerce_unsized_kind(self, did: DefId) -> adjustment::CustomCoerceUnsized {
2380 self.custom_coerce_unsized_kinds.memoize(did, || {
2381 let (kind, src) = if did.krate != LOCAL_CRATE {
2382 (self.sess.cstore.custom_coerce_unsized_kind(did), "external")
2390 bug!("custom_coerce_unsized_kind: \
2391 {} impl `{}` is missing its kind",
2392 src, self.item_path_str(did));
2398 pub fn impl_or_trait_item(self, id: DefId) -> ImplOrTraitItem<'gcx> {
2399 lookup_locally_or_in_crate_store(
2400 "impl_or_trait_items", id, &self.impl_or_trait_items,
2401 || self.sess.cstore.impl_or_trait_item(self.global_tcx(), id)
2402 .expect("missing ImplOrTraitItem in metadata"))
2405 pub fn trait_item_def_ids(self, id: DefId) -> Rc<Vec<ImplOrTraitItemId>> {
2406 lookup_locally_or_in_crate_store(
2407 "trait_item_def_ids", id, &self.trait_item_def_ids,
2408 || Rc::new(self.sess.cstore.trait_item_def_ids(id)))
2411 /// Returns the trait-ref corresponding to a given impl, or None if it is
2412 /// an inherent impl.
2413 pub fn impl_trait_ref(self, id: DefId) -> Option<TraitRef<'gcx>> {
2414 lookup_locally_or_in_crate_store(
2415 "impl_trait_refs", id, &self.impl_trait_refs,
2416 || self.sess.cstore.impl_trait_ref(self.global_tcx(), id))
2419 /// Returns whether this DefId refers to an impl
2420 pub fn is_impl(self, id: DefId) -> bool {
2421 if let Some(id) = self.map.as_local_node_id(id) {
2422 if let Some(ast_map::NodeItem(
2423 &hir::Item { node: hir::ItemImpl(..), .. })) = self.map.find(id) {
2429 self.sess.cstore.is_impl(id)
2433 /// Returns a path resolution for node id if it exists, panics otherwise.
2434 pub fn expect_resolution(self, id: NodeId) -> PathResolution {
2435 *self.def_map.borrow().get(&id).expect("no def-map entry for node id")
2438 /// Returns a fully resolved definition for node id if it exists, panics otherwise.
2439 pub fn expect_def(self, id: NodeId) -> Def {
2440 self.expect_resolution(id).full_def()
2443 /// Returns a fully resolved definition for node id if it exists, or none if no
2444 /// definition exists, panics on partial resolutions to catch errors.
2445 pub fn expect_def_or_none(self, id: NodeId) -> Option<Def> {
2446 self.def_map.borrow().get(&id).map(|resolution| resolution.full_def())
2449 // Returns `ty::VariantDef` if `def` refers to a struct,
2450 // or variant or their constructors, panics otherwise.
2451 pub fn expect_variant_def(self, def: Def) -> VariantDef<'tcx> {
2453 Def::Variant(enum_did, did) => {
2454 self.lookup_adt_def(enum_did).variant_with_id(did)
2456 Def::Struct(did) => {
2457 self.lookup_adt_def(did).struct_variant()
2459 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2463 pub fn def_key(self, id: DefId) -> ast_map::DefKey {
2465 self.map.def_key(id)
2467 self.sess.cstore.def_key(id)
2471 /// Returns the `DefPath` of an item. Note that if `id` is not
2472 /// local to this crate -- or is inlined into this crate -- the
2473 /// result will be a non-local `DefPath`.
2474 pub fn def_path(self, id: DefId) -> ast_map::DefPath {
2476 self.map.def_path(id)
2478 self.sess.cstore.relative_def_path(id)
2482 pub fn item_name(self, id: DefId) -> ast::Name {
2483 if let Some(id) = self.map.as_local_node_id(id) {
2486 self.sess.cstore.item_name(id)
2490 // Register a given item type
2491 pub fn register_item_type(self, did: DefId, ty: TypeScheme<'gcx>) {
2492 self.tcache.borrow_mut().insert(did, ty);
2495 // If the given item is in an external crate, looks up its type and adds it to
2496 // the type cache. Returns the type parameters and type.
2497 pub fn lookup_item_type(self, did: DefId) -> TypeScheme<'gcx> {
2498 lookup_locally_or_in_crate_store(
2499 "tcache", did, &self.tcache,
2500 || self.sess.cstore.item_type(self.global_tcx(), did))
2503 pub fn opt_lookup_item_type(self, did: DefId) -> Option<TypeScheme<'gcx>> {
2504 if let Some(scheme) = self.tcache.borrow_mut().get(&did) {
2505 return Some(scheme.clone());
2508 if did.krate == LOCAL_CRATE {
2511 Some(self.sess.cstore.item_type(self.global_tcx(), did))
2515 /// Given the did of a trait, returns its canonical trait ref.
2516 pub fn lookup_trait_def(self, did: DefId) -> &'gcx TraitDef<'gcx> {
2517 lookup_locally_or_in_crate_store(
2518 "trait_defs", did, &self.trait_defs,
2519 || self.alloc_trait_def(self.sess.cstore.trait_def(self.global_tcx(), did))
2523 /// Given the did of an ADT, return a master reference to its
2524 /// definition. Unless you are planning on fulfilling the ADT's fields,
2525 /// use lookup_adt_def instead.
2526 pub fn lookup_adt_def_master(self, did: DefId) -> AdtDefMaster<'gcx> {
2527 lookup_locally_or_in_crate_store(
2528 "adt_defs", did, &self.adt_defs,
2529 || self.sess.cstore.adt_def(self.global_tcx(), did)
2533 /// Given the did of an ADT, return a reference to its definition.
2534 pub fn lookup_adt_def(self, did: DefId) -> AdtDef<'gcx> {
2535 // when reverse-variance goes away, a transmute::<AdtDefMaster,AdtDef>
2536 // would be needed here.
2537 self.lookup_adt_def_master(did)
2540 /// Given the did of an item, returns its full set of predicates.
2541 pub fn lookup_predicates(self, did: DefId) -> GenericPredicates<'gcx> {
2542 lookup_locally_or_in_crate_store(
2543 "predicates", did, &self.predicates,
2544 || self.sess.cstore.item_predicates(self.global_tcx(), did))
2547 /// Given the did of a trait, returns its superpredicates.
2548 pub fn lookup_super_predicates(self, did: DefId) -> GenericPredicates<'gcx> {
2549 lookup_locally_or_in_crate_store(
2550 "super_predicates", did, &self.super_predicates,
2551 || self.sess.cstore.item_super_predicates(self.global_tcx(), did))
2554 /// If `type_needs_drop` returns true, then `ty` is definitely
2555 /// non-copy and *might* have a destructor attached; if it returns
2556 /// false, then `ty` definitely has no destructor (i.e. no drop glue).
2558 /// (Note that this implies that if `ty` has a destructor attached,
2559 /// then `type_needs_drop` will definitely return `true` for `ty`.)
2560 pub fn type_needs_drop_given_env(self,
2562 param_env: &ty::ParameterEnvironment<'gcx>) -> bool {
2563 // Issue #22536: We first query type_moves_by_default. It sees a
2564 // normalized version of the type, and therefore will definitely
2565 // know whether the type implements Copy (and thus needs no
2566 // cleanup/drop/zeroing) ...
2567 let tcx = self.global_tcx();
2568 let implements_copy = !ty.moves_by_default(tcx, param_env, DUMMY_SP);
2570 if implements_copy { return false; }
2572 // ... (issue #22536 continued) but as an optimization, still use
2573 // prior logic of asking if the `needs_drop` bit is set; we need
2574 // not zero non-Copy types if they have no destructor.
2576 // FIXME(#22815): Note that calling `ty::type_contents` is a
2577 // conservative heuristic; it may report that `needs_drop` is set
2578 // when actual type does not actually have a destructor associated
2579 // with it. But since `ty` absolutely did not have the `Copy`
2580 // bound attached (see above), it is sound to treat it as having a
2581 // destructor (e.g. zero its memory on move).
2583 let contents = ty.type_contents(tcx);
2584 debug!("type_needs_drop ty={:?} contents={:?}", ty, contents);
2585 contents.needs_drop(tcx)
2588 /// Get the attributes of a definition.
2589 pub fn get_attrs(self, did: DefId) -> Cow<'gcx, [ast::Attribute]> {
2590 if let Some(id) = self.map.as_local_node_id(did) {
2591 Cow::Borrowed(self.map.attrs(id))
2593 Cow::Owned(self.sess.cstore.item_attrs(did))
2597 /// Determine whether an item is annotated with an attribute
2598 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2599 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2602 /// Determine whether an item is annotated with `#[repr(packed)]`
2603 pub fn lookup_packed(self, did: DefId) -> bool {
2604 self.lookup_repr_hints(did).contains(&attr::ReprPacked)
2607 /// Determine whether an item is annotated with `#[simd]`
2608 pub fn lookup_simd(self, did: DefId) -> bool {
2609 self.has_attr(did, "simd")
2610 || self.lookup_repr_hints(did).contains(&attr::ReprSimd)
2613 pub fn item_variances(self, item_id: DefId) -> Rc<ItemVariances> {
2614 lookup_locally_or_in_crate_store(
2615 "item_variance_map", item_id, &self.item_variance_map,
2616 || Rc::new(self.sess.cstore.item_variances(item_id)))
2619 pub fn trait_has_default_impl(self, trait_def_id: DefId) -> bool {
2620 self.populate_implementations_for_trait_if_necessary(trait_def_id);
2622 let def = self.lookup_trait_def(trait_def_id);
2623 def.flags.get().intersects(TraitFlags::HAS_DEFAULT_IMPL)
2626 /// Records a trait-to-implementation mapping.
2627 pub fn record_trait_has_default_impl(self, trait_def_id: DefId) {
2628 let def = self.lookup_trait_def(trait_def_id);
2629 def.flags.set(def.flags.get() | TraitFlags::HAS_DEFAULT_IMPL)
2632 /// Load primitive inherent implementations if necessary
2633 pub fn populate_implementations_for_primitive_if_necessary(self,
2634 primitive_def_id: DefId) {
2635 if primitive_def_id.is_local() {
2639 // The primitive is not local, hence we are reading this out
2641 let _ignore = self.dep_graph.in_ignore();
2643 if self.populated_external_primitive_impls.borrow().contains(&primitive_def_id) {
2647 debug!("populate_implementations_for_primitive_if_necessary: searching for {:?}",
2650 let impl_items = self.sess.cstore.impl_items(primitive_def_id);
2652 // Store the implementation info.
2653 self.impl_items.borrow_mut().insert(primitive_def_id, impl_items);
2654 self.populated_external_primitive_impls.borrow_mut().insert(primitive_def_id);
2657 /// Populates the type context with all the inherent implementations for
2658 /// the given type if necessary.
2659 pub fn populate_inherent_implementations_for_type_if_necessary(self,
2661 if type_id.is_local() {
2665 // The type is not local, hence we are reading this out of
2666 // metadata and don't need to track edges.
2667 let _ignore = self.dep_graph.in_ignore();
2669 if self.populated_external_types.borrow().contains(&type_id) {
2673 debug!("populate_inherent_implementations_for_type_if_necessary: searching for {:?}",
2676 let inherent_impls = self.sess.cstore.inherent_implementations_for_type(type_id);
2677 for &impl_def_id in &inherent_impls {
2678 // Store the implementation info.
2679 let impl_items = self.sess.cstore.impl_items(impl_def_id);
2680 self.impl_items.borrow_mut().insert(impl_def_id, impl_items);
2683 self.inherent_impls.borrow_mut().insert(type_id, Rc::new(inherent_impls));
2684 self.populated_external_types.borrow_mut().insert(type_id);
2687 /// Populates the type context with all the implementations for the given
2688 /// trait if necessary.
2689 pub fn populate_implementations_for_trait_if_necessary(self, trait_id: DefId) {
2690 if trait_id.is_local() {
2694 // The type is not local, hence we are reading this out of
2695 // metadata and don't need to track edges.
2696 let _ignore = self.dep_graph.in_ignore();
2698 let def = self.lookup_trait_def(trait_id);
2699 if def.flags.get().intersects(TraitFlags::IMPLS_VALID) {
2703 debug!("populate_implementations_for_trait_if_necessary: searching for {:?}", def);
2705 if self.sess.cstore.is_defaulted_trait(trait_id) {
2706 self.record_trait_has_default_impl(trait_id);
2709 for impl_def_id in self.sess.cstore.implementations_of_trait(trait_id) {
2710 let impl_items = self.sess.cstore.impl_items(impl_def_id);
2711 let trait_ref = self.impl_trait_ref(impl_def_id).unwrap();
2713 // Record the trait->implementation mapping.
2714 if let Some(parent) = self.sess.cstore.impl_parent(impl_def_id) {
2715 def.record_remote_impl(self, impl_def_id, trait_ref, parent);
2717 def.record_remote_impl(self, impl_def_id, trait_ref, trait_id);
2720 // For any methods that use a default implementation, add them to
2721 // the map. This is a bit unfortunate.
2722 for impl_item_def_id in &impl_items {
2723 let method_def_id = impl_item_def_id.def_id();
2724 // load impl items eagerly for convenience
2725 // FIXME: we may want to load these lazily
2726 self.impl_or_trait_item(method_def_id);
2729 // Store the implementation info.
2730 self.impl_items.borrow_mut().insert(impl_def_id, impl_items);
2733 def.flags.set(def.flags.get() | TraitFlags::IMPLS_VALID);
2736 pub fn closure_kind(self, def_id: DefId) -> ty::ClosureKind {
2737 // If this is a local def-id, it should be inserted into the
2738 // tables by typeck; else, it will be retreived from
2739 // the external crate metadata.
2740 if let Some(&kind) = self.tables.borrow().closure_kinds.get(&def_id) {
2744 let kind = self.sess.cstore.closure_kind(def_id);
2745 self.tables.borrow_mut().closure_kinds.insert(def_id, kind);
2749 pub fn closure_type(self,
2751 substs: ClosureSubsts<'tcx>)
2752 -> ty::ClosureTy<'tcx>
2754 // If this is a local def-id, it should be inserted into the
2755 // tables by typeck; else, it will be retreived from
2756 // the external crate metadata.
2757 if let Some(ty) = self.tables.borrow().closure_tys.get(&def_id) {
2758 return ty.subst(self, substs.func_substs);
2761 let ty = self.sess.cstore.closure_ty(self.global_tcx(), def_id);
2762 self.tables.borrow_mut().closure_tys.insert(def_id, ty.clone());
2763 ty.subst(self, substs.func_substs)
2766 /// Given the def_id of an impl, return the def_id of the trait it implements.
2767 /// If it implements no trait, return `None`.
2768 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2769 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2772 /// If the given def ID describes a method belonging to an impl, return the
2773 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2774 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2775 if def_id.krate != LOCAL_CRATE {
2776 return self.sess.cstore.impl_or_trait_item(self.global_tcx(), def_id)
2778 match item.container() {
2779 TraitContainer(_) => None,
2780 ImplContainer(def_id) => Some(def_id),
2784 match self.impl_or_trait_items.borrow().get(&def_id).cloned() {
2785 Some(trait_item) => {
2786 match trait_item.container() {
2787 TraitContainer(_) => None,
2788 ImplContainer(def_id) => Some(def_id),
2795 /// If the given def ID describes an item belonging to a trait (either a
2796 /// default method or an implementation of a trait method), return the ID of
2797 /// the trait that the method belongs to. Otherwise, return `None`.
2798 pub fn trait_of_item(self, def_id: DefId) -> Option<DefId> {
2799 if def_id.krate != LOCAL_CRATE {
2800 return self.sess.cstore.trait_of_item(self.global_tcx(), def_id);
2802 match self.impl_or_trait_items.borrow().get(&def_id).cloned() {
2803 Some(impl_or_trait_item) => {
2804 match impl_or_trait_item.container() {
2805 TraitContainer(def_id) => Some(def_id),
2806 ImplContainer(def_id) => self.trait_id_of_impl(def_id),
2813 /// If the given def ID describes an item belonging to a trait, (either a
2814 /// default method or an implementation of a trait method), return the ID of
2815 /// the method inside trait definition (this means that if the given def ID
2816 /// is already that of the original trait method, then the return value is
2818 /// Otherwise, return `None`.
2819 pub fn trait_item_of_item(self, def_id: DefId) -> Option<ImplOrTraitItemId> {
2820 let impl_item = match self.impl_or_trait_items.borrow().get(&def_id) {
2821 Some(m) => m.clone(),
2822 None => return None,
2824 let name = impl_item.name();
2825 match self.trait_of_item(def_id) {
2826 Some(trait_did) => {
2827 self.trait_items(trait_did).iter()
2828 .find(|item| item.name() == name)
2829 .map(|item| item.id())
2835 /// Construct a parameter environment suitable for static contexts or other contexts where there
2836 /// are no free type/lifetime parameters in scope.
2837 pub fn empty_parameter_environment(self) -> ParameterEnvironment<'tcx> {
2839 // for an empty parameter environment, there ARE no free
2840 // regions, so it shouldn't matter what we use for the free id
2841 let free_id_outlive = self.region_maps.node_extent(ast::DUMMY_NODE_ID);
2842 ty::ParameterEnvironment {
2843 free_substs: self.mk_substs(Substs::empty()),
2844 caller_bounds: Vec::new(),
2845 implicit_region_bound: ty::ReEmpty,
2846 free_id_outlive: free_id_outlive
2850 /// Constructs and returns a substitution that can be applied to move from
2851 /// the "outer" view of a type or method to the "inner" view.
2852 /// In general, this means converting from bound parameters to
2853 /// free parameters. Since we currently represent bound/free type
2854 /// parameters in the same way, this only has an effect on regions.
2855 pub fn construct_free_substs(self, generics: &Generics<'gcx>,
2856 free_id_outlive: CodeExtent) -> Substs<'gcx> {
2858 let mut types = VecPerParamSpace::empty();
2859 for def in generics.types.as_slice() {
2860 debug!("construct_parameter_environment(): push_types_from_defs: def={:?}",
2862 types.push(def.space, self.global_tcx().mk_param_from_def(def));
2865 // map bound 'a => free 'a
2866 let mut regions = VecPerParamSpace::empty();
2867 for def in generics.regions.as_slice() {
2869 ReFree(FreeRegion { scope: free_id_outlive,
2870 bound_region: def.to_bound_region() });
2871 debug!("push_region_params {:?}", region);
2872 regions.push(def.space, region);
2881 /// See `ParameterEnvironment` struct def'n for details.
2882 /// If you were using `free_id: NodeId`, you might try `self.region_maps.item_extent(free_id)`
2883 /// for the `free_id_outlive` parameter. (But note that that is not always quite right.)
2884 pub fn construct_parameter_environment(self,
2886 generics: &ty::Generics<'gcx>,
2887 generic_predicates: &ty::GenericPredicates<'gcx>,
2888 free_id_outlive: CodeExtent)
2889 -> ParameterEnvironment<'gcx>
2892 // Construct the free substs.
2895 let free_substs = self.construct_free_substs(generics, free_id_outlive);
2898 // Compute the bounds on Self and the type parameters.
2901 let tcx = self.global_tcx();
2902 let bounds = generic_predicates.instantiate(tcx, &free_substs);
2903 let bounds = tcx.liberate_late_bound_regions(free_id_outlive, &ty::Binder(bounds));
2904 let predicates = bounds.predicates.into_vec();
2906 // Finally, we have to normalize the bounds in the environment, in
2907 // case they contain any associated type projections. This process
2908 // can yield errors if the put in illegal associated types, like
2909 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2910 // report these errors right here; this doesn't actually feel
2911 // right to me, because constructing the environment feels like a
2912 // kind of a "idempotent" action, but I'm not sure where would be
2913 // a better place. In practice, we construct environments for
2914 // every fn once during type checking, and we'll abort if there
2915 // are any errors at that point, so after type checking you can be
2916 // sure that this will succeed without errors anyway.
2919 let unnormalized_env = ty::ParameterEnvironment {
2920 free_substs: tcx.mk_substs(free_substs),
2921 implicit_region_bound: ty::ReScope(free_id_outlive),
2922 caller_bounds: predicates,
2923 free_id_outlive: free_id_outlive,
2926 let cause = traits::ObligationCause::misc(span, free_id_outlive.node_id(&self.region_maps));
2927 traits::normalize_param_env_or_error(tcx, unnormalized_env, cause)
2930 pub fn is_method_call(self, expr_id: NodeId) -> bool {
2931 self.tables.borrow().method_map.contains_key(&MethodCall::expr(expr_id))
2934 pub fn is_overloaded_autoderef(self, expr_id: NodeId, autoderefs: u32) -> bool {
2935 self.tables.borrow().method_map.contains_key(&MethodCall::autoderef(expr_id,
2939 pub fn upvar_capture(self, upvar_id: ty::UpvarId) -> Option<ty::UpvarCapture> {
2940 Some(self.tables.borrow().upvar_capture_map.get(&upvar_id).unwrap().clone())
2943 pub fn visit_all_items_in_krate<V,F>(self,
2946 where F: FnMut(DefId) -> DepNode<DefId>, V: Visitor<'gcx>
2948 dep_graph::visit_all_items_in_krate(self.global_tcx(), dep_node_fn, visitor);
2951 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2952 /// with the name of the crate containing the impl.
2953 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, InternedString> {
2954 if impl_did.is_local() {
2955 let node_id = self.map.as_local_node_id(impl_did).unwrap();
2956 Ok(self.map.span(node_id))
2958 Err(self.sess.cstore.crate_name(impl_did.krate))
2963 /// The category of explicit self.
2964 #[derive(Clone, Copy, Eq, PartialEq, Debug)]
2965 pub enum ExplicitSelfCategory {
2968 ByReference(Region, hir::Mutability),
2972 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2973 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2974 F: FnOnce(&[hir::Freevar]) -> T,
2976 match self.freevars.borrow().get(&fid) {
2978 Some(d) => f(&d[..])