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};
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};
58 pub use self::sty::{BareFnTy, FnSig, PolyFnSig};
59 pub use self::sty::{ClosureTy, InferTy, ParamTy, ProjectionTy, TraitObject};
60 pub use self::sty::{ClosureSubsts, TypeAndMut};
61 pub use self::sty::{TraitRef, TypeVariants, PolyTraitRef};
62 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
63 pub use self::sty::{ExistentialProjection, PolyExistentialProjection};
64 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
65 pub use self::sty::Issue32330;
66 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid, SkolemizedRegionVid};
67 pub use self::sty::BoundRegion::*;
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::{TyCtxt, tls};
79 pub use self::context::{CtxtArenas, Lift, Tables};
81 pub use self::trait_def::{TraitDef, TraitFlags};
104 mod structural_impls;
107 pub type Disr = ConstInt;
111 /// The complete set of all analyses described in this module. This is
112 /// produced by the driver and fed to trans and later passes.
114 pub struct CrateAnalysis<'a> {
115 pub export_map: ExportMap,
116 pub access_levels: middle::privacy::AccessLevels,
117 pub reachable: NodeSet,
119 pub glob_map: Option<hir::GlobMap>,
122 #[derive(Copy, Clone)]
129 pub fn is_present(&self) -> bool {
131 TraitDtor(..) => true,
136 pub fn has_drop_flag(&self) -> bool {
139 &TraitDtor(flag) => flag
144 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
145 pub enum ImplOrTraitItemContainer {
146 TraitContainer(DefId),
147 ImplContainer(DefId),
150 impl ImplOrTraitItemContainer {
151 pub fn id(&self) -> DefId {
153 TraitContainer(id) => id,
154 ImplContainer(id) => id,
159 /// The "header" of an impl is everything outside the body: a Self type, a trait
160 /// ref (in the case of a trait impl), and a set of predicates (from the
161 /// bounds/where clauses).
162 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
163 pub struct ImplHeader<'tcx> {
164 pub impl_def_id: DefId,
165 pub self_ty: Ty<'tcx>,
166 pub trait_ref: Option<TraitRef<'tcx>>,
167 pub predicates: Vec<Predicate<'tcx>>,
170 impl<'a, 'gcx, 'tcx> ImplHeader<'tcx> {
171 pub fn with_fresh_ty_vars(selcx: &mut traits::SelectionContext<'a, 'gcx, 'tcx>,
175 let tcx = selcx.tcx();
176 let impl_substs = selcx.infcx().fresh_substs_for_item(DUMMY_SP, impl_def_id);
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
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: &'tcx 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: &'tcx 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: Vec<Variance>,
430 pub regions: Vec<Variance>,
434 pub fn empty() -> ItemVariances {
442 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
444 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
445 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
446 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
447 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
450 #[derive(Clone, Copy, Debug)]
451 pub struct MethodCallee<'tcx> {
452 /// Impl method ID, for inherent methods, or trait method ID, otherwise.
455 pub substs: &'tcx Substs<'tcx>
458 /// With method calls, we store some extra information in
459 /// side tables (i.e method_map). We use
460 /// MethodCall as a key to index into these tables instead of
461 /// just directly using the expression's NodeId. The reason
462 /// for this being that we may apply adjustments (coercions)
463 /// with the resulting expression also needing to use the
464 /// side tables. The problem with this is that we don't
465 /// assign a separate NodeId to this new expression
466 /// and so it would clash with the base expression if both
467 /// needed to add to the side tables. Thus to disambiguate
468 /// we also keep track of whether there's an adjustment in
470 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
471 pub struct MethodCall {
477 pub fn expr(id: NodeId) -> MethodCall {
484 pub fn autoderef(expr_id: NodeId, autoderef: u32) -> MethodCall {
487 autoderef: 1 + autoderef
492 // maps from an expression id that corresponds to a method call to the details
493 // of the method to be invoked
494 pub type MethodMap<'tcx> = FnvHashMap<MethodCall, MethodCallee<'tcx>>;
496 // Contains information needed to resolve types and (in the future) look up
497 // the types of AST nodes.
498 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
499 pub struct CReaderCacheKey {
504 /// Describes the fragment-state associated with a NodeId.
506 /// Currently only unfragmented paths have entries in the table,
507 /// but longer-term this enum is expected to expand to also
508 /// include data for fragmented paths.
509 #[derive(Copy, Clone, Debug)]
510 pub enum FragmentInfo {
511 Moved { var: NodeId, move_expr: NodeId },
512 Assigned { var: NodeId, assign_expr: NodeId, assignee_id: NodeId },
515 // Flags that we track on types. These flags are propagated upwards
516 // through the type during type construction, so that we can quickly
517 // check whether the type has various kinds of types in it without
518 // recursing over the type itself.
520 flags TypeFlags: u32 {
521 const HAS_PARAMS = 1 << 0,
522 const HAS_SELF = 1 << 1,
523 const HAS_TY_INFER = 1 << 2,
524 const HAS_RE_INFER = 1 << 3,
525 const HAS_RE_SKOL = 1 << 4,
526 const HAS_RE_EARLY_BOUND = 1 << 5,
527 const HAS_FREE_REGIONS = 1 << 6,
528 const HAS_TY_ERR = 1 << 7,
529 const HAS_PROJECTION = 1 << 8,
530 const HAS_TY_CLOSURE = 1 << 9,
532 // true if there are "names" of types and regions and so forth
533 // that are local to a particular fn
534 const HAS_LOCAL_NAMES = 1 << 10,
536 // Present if the type belongs in a local type context.
537 // Only set for TyInfer other than Fresh.
538 const KEEP_IN_LOCAL_TCX = 1 << 11,
540 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
541 TypeFlags::HAS_SELF.bits |
542 TypeFlags::HAS_RE_EARLY_BOUND.bits,
544 // Flags representing the nominal content of a type,
545 // computed by FlagsComputation. If you add a new nominal
546 // flag, it should be added here too.
547 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
548 TypeFlags::HAS_SELF.bits |
549 TypeFlags::HAS_TY_INFER.bits |
550 TypeFlags::HAS_RE_INFER.bits |
551 TypeFlags::HAS_RE_EARLY_BOUND.bits |
552 TypeFlags::HAS_FREE_REGIONS.bits |
553 TypeFlags::HAS_TY_ERR.bits |
554 TypeFlags::HAS_PROJECTION.bits |
555 TypeFlags::HAS_TY_CLOSURE.bits |
556 TypeFlags::HAS_LOCAL_NAMES.bits |
557 TypeFlags::KEEP_IN_LOCAL_TCX.bits,
559 // Caches for type_is_sized, type_moves_by_default
560 const SIZEDNESS_CACHED = 1 << 16,
561 const IS_SIZED = 1 << 17,
562 const MOVENESS_CACHED = 1 << 18,
563 const MOVES_BY_DEFAULT = 1 << 19,
567 pub struct TyS<'tcx> {
568 pub sty: TypeVariants<'tcx>,
569 pub flags: Cell<TypeFlags>,
571 // the maximal depth of any bound regions appearing in this type.
575 impl<'tcx> PartialEq for TyS<'tcx> {
577 fn eq(&self, other: &TyS<'tcx>) -> bool {
578 // (self as *const _) == (other as *const _)
579 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
582 impl<'tcx> Eq for TyS<'tcx> {}
584 impl<'tcx> Hash for TyS<'tcx> {
585 fn hash<H: Hasher>(&self, s: &mut H) {
586 (self as *const TyS).hash(s)
590 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
592 impl<'tcx> Encodable for Ty<'tcx> {
593 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
594 cstore::tls::with_encoding_context(s, |ecx, rbml_w| {
595 ecx.encode_ty(rbml_w, *self);
601 impl<'tcx> Decodable for Ty<'tcx> {
602 fn decode<D: Decoder>(d: &mut D) -> Result<Ty<'tcx>, D::Error> {
603 cstore::tls::with_decoding_context(d, |dcx, rbml_r| {
604 Ok(dcx.decode_ty(rbml_r))
610 /// Upvars do not get their own node-id. Instead, we use the pair of
611 /// the original var id (that is, the root variable that is referenced
612 /// by the upvar) and the id of the closure expression.
613 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
616 pub closure_expr_id: NodeId,
619 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
620 pub enum BorrowKind {
621 /// Data must be immutable and is aliasable.
624 /// Data must be immutable but not aliasable. This kind of borrow
625 /// cannot currently be expressed by the user and is used only in
626 /// implicit closure bindings. It is needed when you the closure
627 /// is borrowing or mutating a mutable referent, e.g.:
629 /// let x: &mut isize = ...;
630 /// let y = || *x += 5;
632 /// If we were to try to translate this closure into a more explicit
633 /// form, we'd encounter an error with the code as written:
635 /// struct Env { x: & &mut isize }
636 /// let x: &mut isize = ...;
637 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
638 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
640 /// This is then illegal because you cannot mutate a `&mut` found
641 /// in an aliasable location. To solve, you'd have to translate with
642 /// an `&mut` borrow:
644 /// struct Env { x: & &mut isize }
645 /// let x: &mut isize = ...;
646 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
647 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
649 /// Now the assignment to `**env.x` is legal, but creating a
650 /// mutable pointer to `x` is not because `x` is not mutable. We
651 /// could fix this by declaring `x` as `let mut x`. This is ok in
652 /// user code, if awkward, but extra weird for closures, since the
653 /// borrow is hidden.
655 /// So we introduce a "unique imm" borrow -- the referent is
656 /// immutable, but not aliasable. This solves the problem. For
657 /// simplicity, we don't give users the way to express this
658 /// borrow, it's just used when translating closures.
661 /// Data is mutable and not aliasable.
665 /// Information describing the capture of an upvar. This is computed
666 /// during `typeck`, specifically by `regionck`.
667 #[derive(PartialEq, Clone, Debug, Copy)]
668 pub enum UpvarCapture {
669 /// Upvar is captured by value. This is always true when the
670 /// closure is labeled `move`, but can also be true in other cases
671 /// depending on inference.
674 /// Upvar is captured by reference.
678 #[derive(PartialEq, Clone, Copy)]
679 pub struct UpvarBorrow {
680 /// The kind of borrow: by-ref upvars have access to shared
681 /// immutable borrows, which are not part of the normal language
683 pub kind: BorrowKind,
685 /// Region of the resulting reference.
686 pub region: ty::Region,
689 pub type UpvarCaptureMap = FnvHashMap<UpvarId, UpvarCapture>;
691 #[derive(Copy, Clone)]
692 pub struct ClosureUpvar<'tcx> {
698 #[derive(Clone, Copy, PartialEq)]
699 pub enum IntVarValue {
701 UintType(ast::UintTy),
704 /// Default region to use for the bound of objects that are
705 /// supplied as the value for this type parameter. This is derived
706 /// from `T:'a` annotations appearing in the type definition. If
707 /// this is `None`, then the default is inherited from the
708 /// surrounding context. See RFC #599 for details.
709 #[derive(Copy, Clone)]
710 pub enum ObjectLifetimeDefault {
711 /// Require an explicit annotation. Occurs when multiple
712 /// `T:'a` constraints are found.
715 /// Use the base default, typically 'static, but in a fn body it is a fresh variable
718 /// Use the given region as the default.
723 pub struct TypeParameterDef<'tcx> {
727 pub default_def_id: DefId, // for use in error reporing about defaults
728 pub default: Option<Ty<'tcx>>,
729 pub object_lifetime_default: ObjectLifetimeDefault,
733 pub struct RegionParameterDef {
737 pub bounds: Vec<ty::Region>,
740 impl RegionParameterDef {
741 pub fn to_early_bound_region(&self) -> ty::Region {
742 ty::ReEarlyBound(ty::EarlyBoundRegion {
747 pub fn to_bound_region(&self) -> ty::BoundRegion {
748 // this is an early bound region, so unaffected by #32330
749 ty::BoundRegion::BrNamed(self.def_id, self.name, Issue32330::WontChange)
753 /// Information about the formal type/lifetime parameters associated
754 /// with an item or method. Analogous to hir::Generics.
755 #[derive(Clone, Debug)]
756 pub struct Generics<'tcx> {
757 pub parent: Option<DefId>,
758 pub parent_regions: u32,
759 pub parent_types: u32,
760 pub regions: Vec<RegionParameterDef>,
761 pub types: Vec<TypeParameterDef<'tcx>>,
765 /// Bounds on generics.
767 pub struct GenericPredicates<'tcx> {
768 pub parent: Option<DefId>,
769 pub predicates: Vec<Predicate<'tcx>>,
772 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
773 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
774 -> InstantiatedPredicates<'tcx> {
775 let mut instantiated = InstantiatedPredicates::empty();
776 self.instantiate_into(tcx, &mut instantiated, substs);
779 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
780 -> InstantiatedPredicates<'tcx> {
781 InstantiatedPredicates {
782 predicates: self.predicates.subst(tcx, substs)
786 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
787 instantiated: &mut InstantiatedPredicates<'tcx>,
788 substs: &Substs<'tcx>) {
789 if let Some(def_id) = self.parent {
790 tcx.lookup_predicates(def_id).instantiate_into(tcx, instantiated, substs);
792 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
795 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
796 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
797 -> InstantiatedPredicates<'tcx>
799 assert_eq!(self.parent, None);
800 InstantiatedPredicates {
801 predicates: self.predicates.iter().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 type parameters.
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<...>`
838 /// for some substitutions `...` and T being a closure type.
839 /// Satisfied (or refuted) once we know the closure's kind.
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
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.input_types().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.input_types();
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: Vec<Predicate<'tcx>>,
1200 impl<'tcx> InstantiatedPredicates<'tcx> {
1201 pub fn empty() -> InstantiatedPredicates<'tcx> {
1202 InstantiatedPredicates { predicates: vec![] }
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.types[0]
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.
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 tcx.construct_parameter_environment(impl_item.span,
1292 tcx.region_maps.item_extent(id))
1294 hir::ImplItemKind::Method(_, ref body) => {
1295 let method_def_id = tcx.map.local_def_id(id);
1296 match tcx.impl_or_trait_item(method_def_id) {
1297 MethodTraitItem(ref method_ty) => {
1298 tcx.construct_parameter_environment(
1301 tcx.region_maps.call_site_extent(id, body.id))
1304 bug!("ParameterEnvironment::for_item(): \
1305 got non-method item from impl method?!")
1311 Some(ast_map::NodeTraitItem(trait_item)) => {
1312 match trait_item.node {
1313 hir::TypeTraitItem(..) | hir::ConstTraitItem(..) => {
1314 // associated types don't have their own entry (for some reason),
1315 // so for now just grab environment for the trait
1316 let trait_id = tcx.map.get_parent(id);
1317 let trait_def_id = tcx.map.local_def_id(trait_id);
1318 tcx.construct_parameter_environment(trait_item.span,
1320 tcx.region_maps.item_extent(id))
1322 hir::MethodTraitItem(_, ref body) => {
1323 // Use call-site for extent (unless this is a
1324 // trait method with no default; then fallback
1325 // to the method id).
1326 let method_def_id = tcx.map.local_def_id(id);
1327 match tcx.impl_or_trait_item(method_def_id) {
1328 MethodTraitItem(ref method_ty) => {
1329 let extent = if let Some(ref body) = *body {
1330 // default impl: use call_site extent as free_id_outlive bound.
1331 tcx.region_maps.call_site_extent(id, body.id)
1333 // no default impl: use item extent as free_id_outlive bound.
1334 tcx.region_maps.item_extent(id)
1336 tcx.construct_parameter_environment(
1342 bug!("ParameterEnvironment::for_item(): \
1343 got non-method item from provided \
1350 Some(ast_map::NodeItem(item)) => {
1352 hir::ItemFn(_, _, _, _, _, ref body) => {
1353 // We assume this is a function.
1354 let fn_def_id = tcx.map.local_def_id(id);
1356 tcx.construct_parameter_environment(
1359 tcx.region_maps.call_site_extent(id, body.id))
1362 hir::ItemStruct(..) |
1365 hir::ItemConst(..) |
1366 hir::ItemStatic(..) => {
1367 let def_id = tcx.map.local_def_id(id);
1368 tcx.construct_parameter_environment(item.span,
1370 tcx.region_maps.item_extent(id))
1372 hir::ItemTrait(..) => {
1373 let def_id = tcx.map.local_def_id(id);
1374 tcx.construct_parameter_environment(item.span,
1376 tcx.region_maps.item_extent(id))
1379 span_bug!(item.span,
1380 "ParameterEnvironment::for_item():
1381 can't create a parameter \
1382 environment for this kind of item")
1386 Some(ast_map::NodeExpr(expr)) => {
1387 // This is a convenience to allow closures to work.
1388 if let hir::ExprClosure(..) = expr.node {
1389 ParameterEnvironment::for_item(tcx, tcx.map.get_parent(id))
1391 tcx.empty_parameter_environment()
1394 Some(ast_map::NodeForeignItem(item)) => {
1395 let def_id = tcx.map.local_def_id(id);
1396 tcx.construct_parameter_environment(item.span,
1401 bug!("ParameterEnvironment::from_item(): \
1402 `{}` is not an item",
1403 tcx.map.node_to_string(id))
1409 /// A "type scheme", in ML terminology, is a type combined with some
1410 /// set of generic types that the type is, well, generic over. In Rust
1411 /// terms, it is the "type" of a fn item or struct -- this type will
1412 /// include various generic parameters that must be substituted when
1413 /// the item/struct is referenced. That is called converting the type
1414 /// scheme to a monotype.
1416 /// - `generics`: the set of type parameters and their bounds
1417 /// - `ty`: the base types, which may reference the parameters defined
1420 /// Note that TypeSchemes are also sometimes called "polytypes" (and
1421 /// in fact this struct used to carry that name, so you may find some
1422 /// stray references in a comment or something). We try to reserve the
1423 /// "poly" prefix to refer to higher-ranked things, as in
1426 /// Note that each item also comes with predicates, see
1427 /// `lookup_predicates`.
1428 #[derive(Clone, Debug)]
1429 pub struct TypeScheme<'tcx> {
1430 pub generics: &'tcx Generics<'tcx>,
1435 flags AdtFlags: u32 {
1436 const NO_ADT_FLAGS = 0,
1437 const IS_ENUM = 1 << 0,
1438 const IS_DTORCK = 1 << 1, // is this a dtorck type?
1439 const IS_DTORCK_VALID = 1 << 2,
1440 const IS_PHANTOM_DATA = 1 << 3,
1441 const IS_SIMD = 1 << 4,
1442 const IS_FUNDAMENTAL = 1 << 5,
1443 const IS_NO_DROP_FLAG = 1 << 6,
1447 pub type AdtDef<'tcx> = &'tcx AdtDefData<'tcx, 'static>;
1448 pub type VariantDef<'tcx> = &'tcx VariantDefData<'tcx, 'static>;
1449 pub type FieldDef<'tcx> = &'tcx FieldDefData<'tcx, 'static>;
1451 // See comment on AdtDefData for explanation
1452 pub type AdtDefMaster<'tcx> = &'tcx AdtDefData<'tcx, 'tcx>;
1453 pub type VariantDefMaster<'tcx> = &'tcx VariantDefData<'tcx, 'tcx>;
1454 pub type FieldDefMaster<'tcx> = &'tcx FieldDefData<'tcx, 'tcx>;
1456 pub struct VariantDefData<'tcx, 'container: 'tcx> {
1457 /// The variant's DefId. If this is a tuple-like struct,
1458 /// this is the DefId of the struct's ctor.
1460 pub name: Name, // struct's name if this is a struct
1462 pub fields: Vec<FieldDefData<'tcx, 'container>>,
1463 pub kind: VariantKind,
1466 pub struct FieldDefData<'tcx, 'container: 'tcx> {
1467 /// The field's DefId. NOTE: the fields of tuple-like enum variants
1468 /// are not real items, and don't have entries in tcache etc.
1471 pub vis: Visibility,
1472 /// TyIVar is used here to allow for variance (see the doc at
1475 /// Note: direct accesses to `ty` must also add dep edges.
1476 ty: ivar::TyIVar<'tcx, 'container>
1479 /// The definition of an abstract data type - a struct or enum.
1481 /// These are all interned (by intern_adt_def) into the adt_defs
1484 /// Because of the possibility of nested tcx-s, this type
1485 /// needs 2 lifetimes: the traditional variant lifetime ('tcx)
1486 /// bounding the lifetime of the inner types is of course necessary.
1487 /// However, it is not sufficient - types from a child tcx must
1488 /// not be leaked into the master tcx by being stored in an AdtDefData.
1490 /// The 'container lifetime ensures that by outliving the container
1491 /// tcx and preventing shorter-lived types from being inserted. When
1492 /// write access is not needed, the 'container lifetime can be
1493 /// erased to 'static, which can be done by the AdtDef wrapper.
1494 pub struct AdtDefData<'tcx, 'container: 'tcx> {
1496 pub variants: Vec<VariantDefData<'tcx, 'container>>,
1497 destructor: Cell<Option<DefId>>,
1498 flags: Cell<AdtFlags>,
1499 sized_constraint: ivar::TyIVar<'tcx, 'container>,
1502 impl<'tcx, 'container> PartialEq for AdtDefData<'tcx, 'container> {
1503 // AdtDefData are always interned and this is part of TyS equality
1505 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1508 impl<'tcx, 'container> Eq for AdtDefData<'tcx, 'container> {}
1510 impl<'tcx, 'container> Hash for AdtDefData<'tcx, 'container> {
1512 fn hash<H: Hasher>(&self, s: &mut H) {
1513 (self as *const AdtDefData).hash(s)
1517 impl<'tcx> Encodable for AdtDef<'tcx> {
1518 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1523 impl<'tcx> Decodable for AdtDef<'tcx> {
1524 fn decode<D: Decoder>(d: &mut D) -> Result<AdtDef<'tcx>, D::Error> {
1525 let def_id: DefId = Decodable::decode(d)?;
1527 cstore::tls::with_decoding_context(d, |dcx, _| {
1528 let def_id = dcx.translate_def_id(def_id);
1529 Ok(dcx.tcx().lookup_adt_def(def_id))
1535 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1536 pub enum AdtKind { Struct, Enum }
1538 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1539 pub enum VariantKind { Struct, Tuple, Unit }
1542 pub fn from_variant_data(vdata: &hir::VariantData) -> Self {
1544 hir::VariantData::Struct(..) => VariantKind::Struct,
1545 hir::VariantData::Tuple(..) => VariantKind::Tuple,
1546 hir::VariantData::Unit(..) => VariantKind::Unit,
1551 impl<'a, 'gcx, 'tcx, 'container> AdtDefData<'gcx, 'container> {
1552 fn new(tcx: TyCtxt<'a, 'gcx, 'tcx>,
1555 variants: Vec<VariantDefData<'gcx, 'container>>) -> Self {
1556 let mut flags = AdtFlags::NO_ADT_FLAGS;
1557 let attrs = tcx.get_attrs(did);
1558 if attr::contains_name(&attrs, "fundamental") {
1559 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1561 if attr::contains_name(&attrs, "unsafe_no_drop_flag") {
1562 flags = flags | AdtFlags::IS_NO_DROP_FLAG;
1564 if tcx.lookup_simd(did) {
1565 flags = flags | AdtFlags::IS_SIMD;
1567 if Some(did) == tcx.lang_items.phantom_data() {
1568 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1570 if let AdtKind::Enum = kind {
1571 flags = flags | AdtFlags::IS_ENUM;
1576 flags: Cell::new(flags),
1577 destructor: Cell::new(None),
1578 sized_constraint: ivar::TyIVar::new(),
1582 fn calculate_dtorck(&'gcx self, tcx: TyCtxt) {
1583 if tcx.is_adt_dtorck(self) {
1584 self.flags.set(self.flags.get() | AdtFlags::IS_DTORCK);
1586 self.flags.set(self.flags.get() | AdtFlags::IS_DTORCK_VALID)
1589 /// Returns the kind of the ADT - Struct or Enum.
1591 pub fn adt_kind(&self) -> AdtKind {
1592 if self.flags.get().intersects(AdtFlags::IS_ENUM) {
1599 /// Returns whether this is a dtorck type. If this returns
1600 /// true, this type being safe for destruction requires it to be
1601 /// alive; Otherwise, only the contents are required to be.
1603 pub fn is_dtorck(&'gcx self, tcx: TyCtxt) -> bool {
1604 if !self.flags.get().intersects(AdtFlags::IS_DTORCK_VALID) {
1605 self.calculate_dtorck(tcx)
1607 self.flags.get().intersects(AdtFlags::IS_DTORCK)
1610 /// Returns whether this type is #[fundamental] for the purposes
1611 /// of coherence checking.
1613 pub fn is_fundamental(&self) -> bool {
1614 self.flags.get().intersects(AdtFlags::IS_FUNDAMENTAL)
1618 pub fn is_simd(&self) -> bool {
1619 self.flags.get().intersects(AdtFlags::IS_SIMD)
1622 /// Returns true if this is PhantomData<T>.
1624 pub fn is_phantom_data(&self) -> bool {
1625 self.flags.get().intersects(AdtFlags::IS_PHANTOM_DATA)
1628 /// Returns whether this type has a destructor.
1629 pub fn has_dtor(&self) -> bool {
1630 match self.dtor_kind() {
1632 TraitDtor(..) => true
1636 /// Asserts this is a struct and returns the struct's unique
1638 pub fn struct_variant(&self) -> &VariantDefData<'gcx, 'container> {
1639 assert_eq!(self.adt_kind(), AdtKind::Struct);
1644 pub fn type_scheme(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> TypeScheme<'gcx> {
1645 tcx.lookup_item_type(self.did)
1649 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
1650 tcx.lookup_predicates(self.did)
1653 /// Returns an iterator over all fields contained
1656 pub fn all_fields(&self) ->
1658 slice::Iter<VariantDefData<'gcx, 'container>>,
1659 slice::Iter<FieldDefData<'gcx, 'container>>,
1660 for<'s> fn(&'s VariantDefData<'gcx, 'container>)
1661 -> slice::Iter<'s, FieldDefData<'gcx, 'container>>
1663 self.variants.iter().flat_map(VariantDefData::fields_iter)
1667 pub fn is_empty(&self) -> bool {
1668 self.variants.is_empty()
1672 pub fn is_univariant(&self) -> bool {
1673 self.variants.len() == 1
1676 pub fn is_payloadfree(&self) -> bool {
1677 !self.variants.is_empty() &&
1678 self.variants.iter().all(|v| v.fields.is_empty())
1681 pub fn variant_with_id(&self, vid: DefId) -> &VariantDefData<'gcx, 'container> {
1684 .find(|v| v.did == vid)
1685 .expect("variant_with_id: unknown variant")
1688 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1691 .position(|v| v.did == vid)
1692 .expect("variant_index_with_id: unknown variant")
1695 pub fn variant_of_def(&self, def: Def) -> &VariantDefData<'gcx, 'container> {
1697 Def::Variant(_, vid) => self.variant_with_id(vid),
1698 Def::Struct(..) | Def::TyAlias(..) | Def::AssociatedTy(..) => self.struct_variant(),
1699 _ => bug!("unexpected def {:?} in variant_of_def", def)
1703 pub fn destructor(&self) -> Option<DefId> {
1704 self.destructor.get()
1707 pub fn set_destructor(&self, dtor: DefId) {
1708 self.destructor.set(Some(dtor));
1711 pub fn dtor_kind(&self) -> DtorKind {
1712 match self.destructor.get() {
1714 TraitDtor(!self.flags.get().intersects(AdtFlags::IS_NO_DROP_FLAG))
1721 impl<'a, 'gcx, 'tcx, 'container> AdtDefData<'tcx, 'container> {
1722 /// Returns a simpler type such that `Self: Sized` if and only
1723 /// if that type is Sized, or `TyErr` if this type is recursive.
1725 /// HACK: instead of returning a list of types, this function can
1726 /// return a tuple. In that case, the result is Sized only if
1727 /// all elements of the tuple are Sized.
1729 /// This is generally the `struct_tail` if this is a struct, or a
1730 /// tuple of them if this is an enum.
1732 /// Oddly enough, checking that the sized-constraint is Sized is
1733 /// actually more expressive than checking all members:
1734 /// the Sized trait is inductive, so an associated type that references
1735 /// Self would prevent its containing ADT from being Sized.
1737 /// Due to normalization being eager, this applies even if
1738 /// the associated type is behind a pointer, e.g. issue #31299.
1739 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Ty<'tcx> {
1740 match self.sized_constraint.get(DepNode::SizedConstraint(self.did)) {
1742 let global_tcx = tcx.global_tcx();
1743 let this = global_tcx.lookup_adt_def_master(self.did);
1744 this.calculate_sized_constraint_inner(global_tcx, &mut Vec::new());
1745 self.sized_constraint(tcx)
1752 impl<'a, 'tcx> AdtDefData<'tcx, 'tcx> {
1753 /// Calculates the Sized-constraint.
1755 /// As the Sized-constraint of enums can be a *set* of types,
1756 /// the Sized-constraint may need to be a set also. Because introducing
1757 /// a new type of IVar is currently a complex affair, the Sized-constraint
1760 /// In fact, there are only a few options for the constraint:
1761 /// - `bool`, if the type is always Sized
1762 /// - an obviously-unsized type
1763 /// - a type parameter or projection whose Sizedness can't be known
1764 /// - a tuple of type parameters or projections, if there are multiple
1766 /// - a TyError, if a type contained itself. The representability
1767 /// check should catch this case.
1768 fn calculate_sized_constraint_inner(&'tcx self,
1769 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1770 stack: &mut Vec<AdtDefMaster<'tcx>>)
1772 let dep_node = || DepNode::SizedConstraint(self.did);
1774 // Follow the memoization pattern: push the computation of
1775 // DepNode::SizedConstraint as our current task.
1776 let _task = tcx.dep_graph.in_task(dep_node());
1777 if self.sized_constraint.untracked_get().is_some() {
1779 // can skip the dep-graph read since we just pushed the task
1783 if stack.contains(&self) {
1784 debug!("calculate_sized_constraint: {:?} is recursive", self);
1785 // This should be reported as an error by `check_representable`.
1787 // Consider the type as Sized in the meanwhile to avoid
1789 self.sized_constraint.fulfill(dep_node(), tcx.types.err);
1796 self.variants.iter().flat_map(|v| {
1799 self.sized_constraint_for_ty(tcx, stack, f.unsubst_ty())
1802 let self_ = stack.pop().unwrap();
1803 assert_eq!(self_, self);
1805 let ty = match tys.len() {
1806 _ if tys.references_error() => tcx.types.err,
1807 0 => tcx.types.bool,
1809 _ => tcx.mk_tup(tys)
1812 match self.sized_constraint.get(dep_node()) {
1814 debug!("calculate_sized_constraint: {:?} recurred", self);
1815 assert_eq!(old_ty, tcx.types.err)
1818 debug!("calculate_sized_constraint: {:?} => {:?}", self, ty);
1819 self.sized_constraint.fulfill(dep_node(), ty)
1824 fn sized_constraint_for_ty(
1826 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1827 stack: &mut Vec<AdtDefMaster<'tcx>>,
1829 ) -> Vec<Ty<'tcx>> {
1830 let result = match ty.sty {
1831 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
1832 TyBox(..) | TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
1833 TyArray(..) | TyClosure(..) | TyNever => {
1837 TyStr | TyTrait(..) | TySlice(_) | TyError => {
1838 // these are never sized - return the target type
1842 TyTuple(ref tys) => {
1843 // FIXME(#33242) we only need to constrain the last field
1844 tys.iter().flat_map(|ty| {
1845 self.sized_constraint_for_ty(tcx, stack, ty)
1849 TyEnum(adt, substs) | TyStruct(adt, substs) => {
1851 let adt = tcx.lookup_adt_def_master(adt.did);
1852 adt.calculate_sized_constraint_inner(tcx, stack);
1854 adt.sized_constraint
1855 .unwrap(DepNode::SizedConstraint(adt.did))
1856 .subst(tcx, substs);
1857 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
1859 if let ty::TyTuple(ref tys) = adt_ty.sty {
1860 tys.iter().flat_map(|ty| {
1861 self.sized_constraint_for_ty(tcx, stack, ty)
1864 self.sized_constraint_for_ty(tcx, stack, adt_ty)
1868 TyProjection(..) | TyAnon(..) => {
1869 // must calculate explicitly.
1870 // FIXME: consider special-casing always-Sized projections
1875 // perf hack: if there is a `T: Sized` bound, then
1876 // we know that `T` is Sized and do not need to check
1879 let sized_trait = match tcx.lang_items.sized_trait() {
1881 _ => return vec![ty]
1883 let sized_predicate = Binder(TraitRef {
1884 def_id: sized_trait,
1885 substs: Substs::new_trait(tcx, vec![], vec![], ty)
1887 let predicates = tcx.lookup_predicates(self.did).predicates;
1888 if predicates.into_iter().any(|p| p == sized_predicate) {
1896 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
1900 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
1905 impl<'tcx, 'container> VariantDefData<'tcx, 'container> {
1907 fn fields_iter(&self) -> slice::Iter<FieldDefData<'tcx, 'container>> {
1912 pub fn find_field_named(&self,
1914 -> Option<&FieldDefData<'tcx, 'container>> {
1915 self.fields.iter().find(|f| f.name == name)
1919 pub fn index_of_field_named(&self,
1922 self.fields.iter().position(|f| f.name == name)
1926 pub fn field_named(&self, name: ast::Name) -> &FieldDefData<'tcx, 'container> {
1927 self.find_field_named(name).unwrap()
1931 impl<'a, 'gcx, 'tcx, 'container> FieldDefData<'tcx, 'container> {
1932 pub fn new(did: DefId,
1934 vis: Visibility) -> Self {
1939 ty: ivar::TyIVar::new()
1943 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1944 self.unsubst_ty().subst(tcx, subst)
1947 pub fn unsubst_ty(&self) -> Ty<'tcx> {
1948 self.ty.unwrap(DepNode::FieldTy(self.did))
1951 pub fn fulfill_ty(&self, ty: Ty<'container>) {
1952 self.ty.fulfill(DepNode::FieldTy(self.did), ty);
1956 /// Records the substitutions used to translate the polytype for an
1957 /// item into the monotype of an item reference.
1959 pub struct ItemSubsts<'tcx> {
1960 pub substs: &'tcx Substs<'tcx>,
1963 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1964 pub enum ClosureKind {
1965 // Warning: Ordering is significant here! The ordering is chosen
1966 // because the trait Fn is a subtrait of FnMut and so in turn, and
1967 // hence we order it so that Fn < FnMut < FnOnce.
1973 impl<'a, 'tcx> ClosureKind {
1974 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
1975 let result = match *self {
1976 ClosureKind::Fn => tcx.lang_items.require(FnTraitLangItem),
1977 ClosureKind::FnMut => {
1978 tcx.lang_items.require(FnMutTraitLangItem)
1980 ClosureKind::FnOnce => {
1981 tcx.lang_items.require(FnOnceTraitLangItem)
1985 Ok(trait_did) => trait_did,
1986 Err(err) => tcx.sess.fatal(&err[..]),
1990 /// True if this a type that impls this closure kind
1991 /// must also implement `other`.
1992 pub fn extends(self, other: ty::ClosureKind) -> bool {
1993 match (self, other) {
1994 (ClosureKind::Fn, ClosureKind::Fn) => true,
1995 (ClosureKind::Fn, ClosureKind::FnMut) => true,
1996 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
1997 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
1998 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
1999 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2005 impl<'tcx> TyS<'tcx> {
2006 /// Iterator that walks `self` and any types reachable from
2007 /// `self`, in depth-first order. Note that just walks the types
2008 /// that appear in `self`, it does not descend into the fields of
2009 /// structs or variants. For example:
2012 /// isize => { isize }
2013 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2014 /// [isize] => { [isize], isize }
2016 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2017 TypeWalker::new(self)
2020 /// Iterator that walks the immediate children of `self`. Hence
2021 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2022 /// (but not `i32`, like `walk`).
2023 pub fn walk_shallow(&'tcx self) -> IntoIter<Ty<'tcx>> {
2024 walk::walk_shallow(self)
2027 /// Walks `ty` and any types appearing within `ty`, invoking the
2028 /// callback `f` on each type. If the callback returns false, then the
2029 /// children of the current type are ignored.
2031 /// Note: prefer `ty.walk()` where possible.
2032 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2033 where F : FnMut(Ty<'tcx>) -> bool
2035 let mut walker = self.walk();
2036 while let Some(ty) = walker.next() {
2038 walker.skip_current_subtree();
2044 impl<'tcx> ItemSubsts<'tcx> {
2045 pub fn is_noop(&self) -> bool {
2046 self.substs.is_noop()
2050 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
2051 pub enum LvaluePreference {
2056 impl LvaluePreference {
2057 pub fn from_mutbl(m: hir::Mutability) -> Self {
2059 hir::MutMutable => PreferMutLvalue,
2060 hir::MutImmutable => NoPreference,
2065 /// Helper for looking things up in the various maps that are populated during
2066 /// typeck::collect (e.g., `tcx.impl_or_trait_items`, `tcx.tcache`, etc). All of
2067 /// these share the pattern that if the id is local, it should have been loaded
2068 /// into the map by the `typeck::collect` phase. If the def-id is external,
2069 /// then we have to go consult the crate loading code (and cache the result for
2071 fn lookup_locally_or_in_crate_store<M, F>(descr: &str,
2076 M: MemoizationMap<Key=DefId>,
2077 F: FnOnce() -> M::Value,
2079 map.memoize(def_id, || {
2080 if def_id.is_local() {
2081 bug!("No def'n found for {:?} in tcx.{}", def_id, descr);
2088 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2090 hir::MutMutable => MutBorrow,
2091 hir::MutImmutable => ImmBorrow,
2095 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2096 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2097 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2099 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2101 MutBorrow => hir::MutMutable,
2102 ImmBorrow => hir::MutImmutable,
2104 // We have no type corresponding to a unique imm borrow, so
2105 // use `&mut`. It gives all the capabilities of an `&uniq`
2106 // and hence is a safe "over approximation".
2107 UniqueImmBorrow => hir::MutMutable,
2111 pub fn to_user_str(&self) -> &'static str {
2113 MutBorrow => "mutable",
2114 ImmBorrow => "immutable",
2115 UniqueImmBorrow => "uniquely immutable",
2120 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2121 pub fn node_id_to_type(self, id: NodeId) -> Ty<'gcx> {
2122 match self.node_id_to_type_opt(id) {
2124 None => bug!("node_id_to_type: no type for node `{}`",
2125 self.map.node_to_string(id))
2129 pub fn node_id_to_type_opt(self, id: NodeId) -> Option<Ty<'gcx>> {
2130 self.tables.borrow().node_types.get(&id).cloned()
2133 pub fn node_id_item_substs(self, id: NodeId) -> ItemSubsts<'gcx> {
2134 match self.tables.borrow().item_substs.get(&id) {
2135 None => ItemSubsts {
2136 substs: Substs::empty(self.global_tcx())
2138 Some(ts) => ts.clone(),
2142 // Returns the type of a pattern as a monotype. Like @expr_ty, this function
2143 // doesn't provide type parameter substitutions.
2144 pub fn pat_ty(self, pat: &hir::Pat) -> Ty<'gcx> {
2145 self.node_id_to_type(pat.id)
2147 pub fn pat_ty_opt(self, pat: &hir::Pat) -> Option<Ty<'gcx>> {
2148 self.node_id_to_type_opt(pat.id)
2151 // Returns the type of an expression as a monotype.
2153 // NB (1): This is the PRE-ADJUSTMENT TYPE for the expression. That is, in
2154 // some cases, we insert `AutoAdjustment` annotations such as auto-deref or
2155 // auto-ref. The type returned by this function does not consider such
2156 // adjustments. See `expr_ty_adjusted()` instead.
2158 // NB (2): This type doesn't provide type parameter substitutions; e.g. if you
2159 // ask for the type of "id" in "id(3)", it will return "fn(&isize) -> isize"
2160 // instead of "fn(ty) -> T with T = isize".
2161 pub fn expr_ty(self, expr: &hir::Expr) -> Ty<'gcx> {
2162 self.node_id_to_type(expr.id)
2165 pub fn expr_ty_opt(self, expr: &hir::Expr) -> Option<Ty<'gcx>> {
2166 self.node_id_to_type_opt(expr.id)
2169 /// Returns the type of `expr`, considering any `AutoAdjustment`
2170 /// entry recorded for that expression.
2172 /// It would almost certainly be better to store the adjusted ty in with
2173 /// the `AutoAdjustment`, but I opted not to do this because it would
2174 /// require serializing and deserializing the type and, although that's not
2175 /// hard to do, I just hate that code so much I didn't want to touch it
2176 /// unless it was to fix it properly, which seemed a distraction from the
2177 /// thread at hand! -nmatsakis
2178 pub fn expr_ty_adjusted(self, expr: &hir::Expr) -> Ty<'gcx> {
2180 .adjust(self.global_tcx(), expr.span, expr.id,
2181 self.tables.borrow().adjustments.get(&expr.id),
2183 self.tables.borrow().method_map.get(&method_call).map(|method| method.ty)
2187 pub fn expr_ty_adjusted_opt(self, expr: &hir::Expr) -> Option<Ty<'gcx>> {
2188 self.expr_ty_opt(expr).map(|t| t.adjust(self.global_tcx(),
2191 self.tables.borrow().adjustments.get(&expr.id),
2193 self.tables.borrow().method_map.get(&method_call).map(|method| method.ty)
2197 pub fn expr_span(self, id: NodeId) -> Span {
2198 match self.map.find(id) {
2199 Some(ast_map::NodeExpr(e)) => {
2203 bug!("Node id {} is not an expr: {:?}", id, f);
2206 bug!("Node id {} is not present in the node map", id);
2211 pub fn local_var_name_str(self, id: NodeId) -> InternedString {
2212 match self.map.find(id) {
2213 Some(ast_map::NodeLocal(pat)) => {
2215 PatKind::Binding(_, ref path1, _) => path1.node.as_str(),
2217 bug!("Variable id {} maps to {:?}, not local", id, pat);
2221 r => bug!("Variable id {} maps to {:?}, not local", id, r),
2225 pub fn expr_is_lval(self, expr: &hir::Expr) -> bool {
2227 hir::ExprPath(..) => {
2228 // This function can be used during type checking when not all paths are
2229 // fully resolved. Partially resolved paths in expressions can only legally
2230 // refer to associated items which are always rvalues.
2231 match self.expect_resolution(expr.id).base_def {
2232 Def::Local(..) | Def::Upvar(..) | Def::Static(..) | Def::Err => true,
2237 hir::ExprType(ref e, _) => {
2238 self.expr_is_lval(e)
2241 hir::ExprUnary(hir::UnDeref, _) |
2242 hir::ExprField(..) |
2243 hir::ExprTupField(..) |
2244 hir::ExprIndex(..) => {
2249 hir::ExprMethodCall(..) |
2250 hir::ExprStruct(..) |
2253 hir::ExprMatch(..) |
2254 hir::ExprClosure(..) |
2255 hir::ExprBlock(..) |
2256 hir::ExprRepeat(..) |
2258 hir::ExprBreak(..) |
2259 hir::ExprAgain(..) |
2261 hir::ExprWhile(..) |
2263 hir::ExprAssign(..) |
2264 hir::ExprInlineAsm(..) |
2265 hir::ExprAssignOp(..) |
2267 hir::ExprUnary(..) |
2269 hir::ExprAddrOf(..) |
2270 hir::ExprBinary(..) |
2271 hir::ExprCast(..) => {
2277 pub fn provided_trait_methods(self, id: DefId) -> Vec<Rc<Method<'gcx>>> {
2278 if let Some(id) = self.map.as_local_node_id(id) {
2279 if let ItemTrait(_, _, _, ref ms) = self.map.expect_item(id).node {
2280 ms.iter().filter_map(|ti| {
2281 if let hir::MethodTraitItem(_, Some(_)) = ti.node {
2282 match self.impl_or_trait_item(self.map.local_def_id(ti.id)) {
2283 MethodTraitItem(m) => Some(m),
2285 bug!("provided_trait_methods(): \
2286 non-method item found from \
2287 looking up provided method?!")
2295 bug!("provided_trait_methods: `{:?}` is not a trait", id)
2298 self.sess.cstore.provided_trait_methods(self.global_tcx(), id)
2302 pub fn associated_consts(self, id: DefId) -> Vec<Rc<AssociatedConst<'gcx>>> {
2303 if let Some(id) = self.map.as_local_node_id(id) {
2304 match self.map.expect_item(id).node {
2305 ItemTrait(_, _, _, ref tis) => {
2306 tis.iter().filter_map(|ti| {
2307 if let hir::ConstTraitItem(_, _) = ti.node {
2308 match self.impl_or_trait_item(self.map.local_def_id(ti.id)) {
2309 ConstTraitItem(ac) => Some(ac),
2311 bug!("associated_consts(): \
2312 non-const item found from \
2313 looking up a constant?!")
2321 ItemImpl(_, _, _, _, _, ref iis) => {
2322 iis.iter().filter_map(|ii| {
2323 if let hir::ImplItemKind::Const(_, _) = ii.node {
2324 match self.impl_or_trait_item(self.map.local_def_id(ii.id)) {
2325 ConstTraitItem(ac) => Some(ac),
2327 bug!("associated_consts(): \
2328 non-const item found from \
2329 looking up a constant?!")
2338 bug!("associated_consts: `{:?}` is not a trait or impl", id)
2342 self.sess.cstore.associated_consts(self.global_tcx(), id)
2346 pub fn trait_impl_polarity(self, id: DefId) -> Option<hir::ImplPolarity> {
2347 if let Some(id) = self.map.as_local_node_id(id) {
2348 match self.map.find(id) {
2349 Some(ast_map::NodeItem(item)) => {
2351 hir::ItemImpl(_, polarity, _, _, _, _) => Some(polarity),
2358 self.sess.cstore.impl_polarity(id)
2362 pub fn custom_coerce_unsized_kind(self, did: DefId) -> adjustment::CustomCoerceUnsized {
2363 self.custom_coerce_unsized_kinds.memoize(did, || {
2364 let (kind, src) = if did.krate != LOCAL_CRATE {
2365 (self.sess.cstore.custom_coerce_unsized_kind(did), "external")
2373 bug!("custom_coerce_unsized_kind: \
2374 {} impl `{}` is missing its kind",
2375 src, self.item_path_str(did));
2381 pub fn impl_or_trait_item(self, id: DefId) -> ImplOrTraitItem<'gcx> {
2382 lookup_locally_or_in_crate_store(
2383 "impl_or_trait_items", id, &self.impl_or_trait_items,
2384 || self.sess.cstore.impl_or_trait_item(self.global_tcx(), id)
2385 .expect("missing ImplOrTraitItem in metadata"))
2388 pub fn trait_item_def_ids(self, id: DefId) -> Rc<Vec<ImplOrTraitItemId>> {
2389 lookup_locally_or_in_crate_store(
2390 "trait_item_def_ids", id, &self.trait_item_def_ids,
2391 || Rc::new(self.sess.cstore.trait_item_def_ids(id)))
2394 /// Returns the trait-ref corresponding to a given impl, or None if it is
2395 /// an inherent impl.
2396 pub fn impl_trait_ref(self, id: DefId) -> Option<TraitRef<'gcx>> {
2397 lookup_locally_or_in_crate_store(
2398 "impl_trait_refs", id, &self.impl_trait_refs,
2399 || self.sess.cstore.impl_trait_ref(self.global_tcx(), id))
2402 /// Returns whether this DefId refers to an impl
2403 pub fn is_impl(self, id: DefId) -> bool {
2404 if let Some(id) = self.map.as_local_node_id(id) {
2405 if let Some(ast_map::NodeItem(
2406 &hir::Item { node: hir::ItemImpl(..), .. })) = self.map.find(id) {
2412 self.sess.cstore.is_impl(id)
2416 /// Returns a path resolution for node id if it exists, panics otherwise.
2417 pub fn expect_resolution(self, id: NodeId) -> PathResolution {
2418 *self.def_map.borrow().get(&id).expect("no def-map entry for node id")
2421 /// Returns a fully resolved definition for node id if it exists, panics otherwise.
2422 pub fn expect_def(self, id: NodeId) -> Def {
2423 self.expect_resolution(id).full_def()
2426 /// Returns a fully resolved definition for node id if it exists, or none if no
2427 /// definition exists, panics on partial resolutions to catch errors.
2428 pub fn expect_def_or_none(self, id: NodeId) -> Option<Def> {
2429 self.def_map.borrow().get(&id).map(|resolution| resolution.full_def())
2432 // Returns `ty::VariantDef` if `def` refers to a struct,
2433 // or variant or their constructors, panics otherwise.
2434 pub fn expect_variant_def(self, def: Def) -> VariantDef<'tcx> {
2436 Def::Variant(enum_did, did) => {
2437 self.lookup_adt_def(enum_did).variant_with_id(did)
2439 Def::Struct(did) => {
2440 self.lookup_adt_def(did).struct_variant()
2442 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2446 pub fn def_key(self, id: DefId) -> ast_map::DefKey {
2448 self.map.def_key(id)
2450 self.sess.cstore.def_key(id)
2454 /// Returns the `DefPath` of an item. Note that if `id` is not
2455 /// local to this crate -- or is inlined into this crate -- the
2456 /// result will be a non-local `DefPath`.
2457 pub fn def_path(self, id: DefId) -> ast_map::DefPath {
2459 self.map.def_path(id)
2461 self.sess.cstore.relative_def_path(id)
2465 pub fn item_name(self, id: DefId) -> ast::Name {
2466 if let Some(id) = self.map.as_local_node_id(id) {
2469 self.sess.cstore.item_name(id)
2473 // Register a given item type
2474 pub fn register_item_type(self, did: DefId, scheme: TypeScheme<'gcx>) {
2475 self.tcache.borrow_mut().insert(did, scheme.ty);
2476 self.generics.borrow_mut().insert(did, scheme.generics);
2479 // If the given item is in an external crate, looks up its type and adds it to
2480 // the type cache. Returns the type parameters and type.
2481 pub fn lookup_item_type(self, did: DefId) -> TypeScheme<'gcx> {
2482 let ty = lookup_locally_or_in_crate_store(
2483 "tcache", did, &self.tcache,
2484 || self.sess.cstore.item_type(self.global_tcx(), did));
2488 generics: self.lookup_generics(did)
2492 pub fn opt_lookup_item_type(self, did: DefId) -> Option<TypeScheme<'gcx>> {
2493 if did.krate != LOCAL_CRATE {
2494 return Some(self.lookup_item_type(did));
2497 if let Some(ty) = self.tcache.borrow().get(&did).cloned() {
2500 generics: self.lookup_generics(did)
2507 /// Given the did of a trait, returns its canonical trait ref.
2508 pub fn lookup_trait_def(self, did: DefId) -> &'gcx TraitDef<'gcx> {
2509 lookup_locally_or_in_crate_store(
2510 "trait_defs", did, &self.trait_defs,
2511 || self.alloc_trait_def(self.sess.cstore.trait_def(self.global_tcx(), did))
2515 /// Given the did of an ADT, return a master reference to its
2516 /// definition. Unless you are planning on fulfilling the ADT's fields,
2517 /// use lookup_adt_def instead.
2518 pub fn lookup_adt_def_master(self, did: DefId) -> AdtDefMaster<'gcx> {
2519 lookup_locally_or_in_crate_store(
2520 "adt_defs", did, &self.adt_defs,
2521 || self.sess.cstore.adt_def(self.global_tcx(), did)
2525 /// Given the did of an ADT, return a reference to its definition.
2526 pub fn lookup_adt_def(self, did: DefId) -> AdtDef<'gcx> {
2527 // when reverse-variance goes away, a transmute::<AdtDefMaster,AdtDef>
2528 // would be needed here.
2529 self.lookup_adt_def_master(did)
2532 /// Given the did of an item, returns its generics.
2533 pub fn lookup_generics(self, did: DefId) -> &'gcx Generics<'gcx> {
2534 lookup_locally_or_in_crate_store(
2535 "generics", did, &self.generics,
2536 || self.sess.cstore.item_generics(self.global_tcx(), did))
2539 /// Given the did of an item, returns its full set of predicates.
2540 pub fn lookup_predicates(self, did: DefId) -> GenericPredicates<'gcx> {
2541 lookup_locally_or_in_crate_store(
2542 "predicates", did, &self.predicates,
2543 || self.sess.cstore.item_predicates(self.global_tcx(), did))
2546 /// Given the did of a trait, returns its superpredicates.
2547 pub fn lookup_super_predicates(self, did: DefId) -> GenericPredicates<'gcx> {
2548 lookup_locally_or_in_crate_store(
2549 "super_predicates", did, &self.super_predicates,
2550 || self.sess.cstore.item_super_predicates(self.global_tcx(), did))
2553 /// If `type_needs_drop` returns true, then `ty` is definitely
2554 /// non-copy and *might* have a destructor attached; if it returns
2555 /// false, then `ty` definitely has no destructor (i.e. no drop glue).
2557 /// (Note that this implies that if `ty` has a destructor attached,
2558 /// then `type_needs_drop` will definitely return `true` for `ty`.)
2559 pub fn type_needs_drop_given_env(self,
2561 param_env: &ty::ParameterEnvironment<'gcx>) -> bool {
2562 // Issue #22536: We first query type_moves_by_default. It sees a
2563 // normalized version of the type, and therefore will definitely
2564 // know whether the type implements Copy (and thus needs no
2565 // cleanup/drop/zeroing) ...
2566 let tcx = self.global_tcx();
2567 let implements_copy = !ty.moves_by_default(tcx, param_env, DUMMY_SP);
2569 if implements_copy { return false; }
2571 // ... (issue #22536 continued) but as an optimization, still use
2572 // prior logic of asking if the `needs_drop` bit is set; we need
2573 // not zero non-Copy types if they have no destructor.
2575 // FIXME(#22815): Note that calling `ty::type_contents` is a
2576 // conservative heuristic; it may report that `needs_drop` is set
2577 // when actual type does not actually have a destructor associated
2578 // with it. But since `ty` absolutely did not have the `Copy`
2579 // bound attached (see above), it is sound to treat it as having a
2580 // destructor (e.g. zero its memory on move).
2582 let contents = ty.type_contents(tcx);
2583 debug!("type_needs_drop ty={:?} contents={:?}", ty, contents);
2584 contents.needs_drop(tcx)
2587 /// Get the attributes of a definition.
2588 pub fn get_attrs(self, did: DefId) -> Cow<'gcx, [ast::Attribute]> {
2589 if let Some(id) = self.map.as_local_node_id(did) {
2590 Cow::Borrowed(self.map.attrs(id))
2592 Cow::Owned(self.sess.cstore.item_attrs(did))
2596 /// Determine whether an item is annotated with an attribute
2597 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2598 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2601 /// Determine whether an item is annotated with `#[repr(packed)]`
2602 pub fn lookup_packed(self, did: DefId) -> bool {
2603 self.lookup_repr_hints(did).contains(&attr::ReprPacked)
2606 /// Determine whether an item is annotated with `#[simd]`
2607 pub fn lookup_simd(self, did: DefId) -> bool {
2608 self.has_attr(did, "simd")
2609 || self.lookup_repr_hints(did).contains(&attr::ReprSimd)
2612 pub fn item_variances(self, item_id: DefId) -> Rc<ItemVariances> {
2613 lookup_locally_or_in_crate_store(
2614 "item_variance_map", item_id, &self.item_variance_map,
2615 || Rc::new(self.sess.cstore.item_variances(item_id)))
2618 pub fn trait_has_default_impl(self, trait_def_id: DefId) -> bool {
2619 self.populate_implementations_for_trait_if_necessary(trait_def_id);
2621 let def = self.lookup_trait_def(trait_def_id);
2622 def.flags.get().intersects(TraitFlags::HAS_DEFAULT_IMPL)
2625 /// Records a trait-to-implementation mapping.
2626 pub fn record_trait_has_default_impl(self, trait_def_id: DefId) {
2627 let def = self.lookup_trait_def(trait_def_id);
2628 def.flags.set(def.flags.get() | TraitFlags::HAS_DEFAULT_IMPL)
2631 /// Load primitive inherent implementations if necessary
2632 pub fn populate_implementations_for_primitive_if_necessary(self,
2633 primitive_def_id: DefId) {
2634 if primitive_def_id.is_local() {
2638 // The primitive is not local, hence we are reading this out
2640 let _ignore = self.dep_graph.in_ignore();
2642 if self.populated_external_primitive_impls.borrow().contains(&primitive_def_id) {
2646 debug!("populate_implementations_for_primitive_if_necessary: searching for {:?}",
2649 let impl_items = self.sess.cstore.impl_items(primitive_def_id);
2651 // Store the implementation info.
2652 self.impl_items.borrow_mut().insert(primitive_def_id, impl_items);
2653 self.populated_external_primitive_impls.borrow_mut().insert(primitive_def_id);
2656 /// Populates the type context with all the inherent implementations for
2657 /// the given type if necessary.
2658 pub fn populate_inherent_implementations_for_type_if_necessary(self,
2660 if type_id.is_local() {
2664 // The type is not local, hence we are reading this out of
2665 // metadata and don't need to track edges.
2666 let _ignore = self.dep_graph.in_ignore();
2668 if self.populated_external_types.borrow().contains(&type_id) {
2672 debug!("populate_inherent_implementations_for_type_if_necessary: searching for {:?}",
2675 let inherent_impls = self.sess.cstore.inherent_implementations_for_type(type_id);
2676 for &impl_def_id in &inherent_impls {
2677 // Store the implementation info.
2678 let impl_items = self.sess.cstore.impl_items(impl_def_id);
2679 self.impl_items.borrow_mut().insert(impl_def_id, impl_items);
2682 self.inherent_impls.borrow_mut().insert(type_id, Rc::new(inherent_impls));
2683 self.populated_external_types.borrow_mut().insert(type_id);
2686 /// Populates the type context with all the implementations for the given
2687 /// trait if necessary.
2688 pub fn populate_implementations_for_trait_if_necessary(self, trait_id: DefId) {
2689 if trait_id.is_local() {
2693 // The type is not local, hence we are reading this out of
2694 // metadata and don't need to track edges.
2695 let _ignore = self.dep_graph.in_ignore();
2697 let def = self.lookup_trait_def(trait_id);
2698 if def.flags.get().intersects(TraitFlags::IMPLS_VALID) {
2702 debug!("populate_implementations_for_trait_if_necessary: searching for {:?}", def);
2704 if self.sess.cstore.is_defaulted_trait(trait_id) {
2705 self.record_trait_has_default_impl(trait_id);
2708 for impl_def_id in self.sess.cstore.implementations_of_trait(trait_id) {
2709 let impl_items = self.sess.cstore.impl_items(impl_def_id);
2710 let trait_ref = self.impl_trait_ref(impl_def_id).unwrap();
2712 // Record the trait->implementation mapping.
2713 if let Some(parent) = self.sess.cstore.impl_parent(impl_def_id) {
2714 def.record_remote_impl(self, impl_def_id, trait_ref, parent);
2716 def.record_remote_impl(self, impl_def_id, trait_ref, trait_id);
2719 // For any methods that use a default implementation, add them to
2720 // the map. This is a bit unfortunate.
2721 for impl_item_def_id in &impl_items {
2722 let method_def_id = impl_item_def_id.def_id();
2723 // load impl items eagerly for convenience
2724 // FIXME: we may want to load these lazily
2725 self.impl_or_trait_item(method_def_id);
2728 // Store the implementation info.
2729 self.impl_items.borrow_mut().insert(impl_def_id, impl_items);
2732 def.flags.set(def.flags.get() | TraitFlags::IMPLS_VALID);
2735 pub fn closure_kind(self, def_id: DefId) -> ty::ClosureKind {
2736 // If this is a local def-id, it should be inserted into the
2737 // tables by typeck; else, it will be retreived from
2738 // the external crate metadata.
2739 if let Some(&kind) = self.tables.borrow().closure_kinds.get(&def_id) {
2743 let kind = self.sess.cstore.closure_kind(def_id);
2744 self.tables.borrow_mut().closure_kinds.insert(def_id, kind);
2748 pub fn closure_type(self,
2750 substs: ClosureSubsts<'tcx>)
2751 -> ty::ClosureTy<'tcx>
2753 // If this is a local def-id, it should be inserted into the
2754 // tables by typeck; else, it will be retreived from
2755 // the external crate metadata.
2756 if let Some(ty) = self.tables.borrow().closure_tys.get(&def_id) {
2757 return ty.subst(self, substs.func_substs);
2760 let ty = self.sess.cstore.closure_ty(self.global_tcx(), def_id);
2761 self.tables.borrow_mut().closure_tys.insert(def_id, ty.clone());
2762 ty.subst(self, substs.func_substs)
2765 /// Given the def_id of an impl, return the def_id of the trait it implements.
2766 /// If it implements no trait, return `None`.
2767 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2768 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2771 /// If the given def ID describes a method belonging to an impl, return the
2772 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2773 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2774 if def_id.krate != LOCAL_CRATE {
2775 return self.sess.cstore.impl_or_trait_item(self.global_tcx(), def_id)
2777 match item.container() {
2778 TraitContainer(_) => None,
2779 ImplContainer(def_id) => Some(def_id),
2783 match self.impl_or_trait_items.borrow().get(&def_id).cloned() {
2784 Some(trait_item) => {
2785 match trait_item.container() {
2786 TraitContainer(_) => None,
2787 ImplContainer(def_id) => Some(def_id),
2794 /// If the given def ID describes an item belonging to a trait,
2795 /// return the ID of the trait that the trait item belongs to.
2796 /// Otherwise, return `None`.
2797 pub fn trait_of_item(self, def_id: DefId) -> Option<DefId> {
2798 if def_id.krate != LOCAL_CRATE {
2799 return self.sess.cstore.trait_of_item(def_id);
2801 match self.impl_or_trait_items.borrow().get(&def_id) {
2802 Some(impl_or_trait_item) => {
2803 match impl_or_trait_item.container() {
2804 TraitContainer(def_id) => Some(def_id),
2805 ImplContainer(_) => None
2812 /// If the given def ID describes an item belonging to a trait, (either a
2813 /// default method or an implementation of a trait method), return the ID of
2814 /// the method inside trait definition (this means that if the given def ID
2815 /// is already that of the original trait method, then the return value is
2817 /// Otherwise, return `None`.
2818 pub fn trait_item_of_item(self, def_id: DefId) -> Option<ImplOrTraitItemId> {
2819 let impl_or_trait_item = match self.impl_or_trait_items.borrow().get(&def_id) {
2820 Some(m) => m.clone(),
2821 None => return None,
2823 match impl_or_trait_item.container() {
2824 TraitContainer(_) => Some(impl_or_trait_item.id()),
2825 ImplContainer(def_id) => {
2826 self.trait_id_of_impl(def_id).and_then(|trait_did| {
2827 let name = impl_or_trait_item.name();
2828 self.trait_items(trait_did).iter()
2829 .find(|item| item.name() == name)
2830 .map(|item| item.id())
2836 /// Construct a parameter environment suitable for static contexts or other contexts where there
2837 /// are no free type/lifetime parameters in scope.
2838 pub fn empty_parameter_environment(self) -> ParameterEnvironment<'tcx> {
2840 // for an empty parameter environment, there ARE no free
2841 // regions, so it shouldn't matter what we use for the free id
2842 let free_id_outlive = self.region_maps.node_extent(ast::DUMMY_NODE_ID);
2843 ty::ParameterEnvironment {
2844 free_substs: Substs::empty(self),
2845 caller_bounds: Vec::new(),
2846 implicit_region_bound: ty::ReEmpty,
2847 free_id_outlive: free_id_outlive
2851 /// Constructs and returns a substitution that can be applied to move from
2852 /// the "outer" view of a type or method to the "inner" view.
2853 /// In general, this means converting from bound parameters to
2854 /// free parameters. Since we currently represent bound/free type
2855 /// parameters in the same way, this only has an effect on regions.
2856 pub fn construct_free_substs(self, def_id: DefId,
2857 free_id_outlive: CodeExtent)
2858 -> &'gcx Substs<'gcx> {
2860 let substs = Substs::for_item(self.global_tcx(), def_id, |def, _| {
2861 // map bound 'a => free 'a
2862 ReFree(FreeRegion { scope: free_id_outlive,
2863 bound_region: def.to_bound_region() })
2866 self.global_tcx().mk_param_from_def(def)
2869 debug!("construct_parameter_environment: {:?}", substs);
2873 /// See `ParameterEnvironment` struct def'n for details.
2874 /// If you were using `free_id: NodeId`, you might try `self.region_maps.item_extent(free_id)`
2875 /// for the `free_id_outlive` parameter. (But note that that is not always quite right.)
2876 pub fn construct_parameter_environment(self,
2879 free_id_outlive: CodeExtent)
2880 -> ParameterEnvironment<'gcx>
2883 // Construct the free substs.
2886 let free_substs = self.construct_free_substs(def_id, free_id_outlive);
2889 // Compute the bounds on Self and the type parameters.
2892 let tcx = self.global_tcx();
2893 let generic_predicates = tcx.lookup_predicates(def_id);
2894 let bounds = generic_predicates.instantiate(tcx, free_substs);
2895 let bounds = tcx.liberate_late_bound_regions(free_id_outlive, &ty::Binder(bounds));
2896 let predicates = bounds.predicates;
2898 // Finally, we have to normalize the bounds in the environment, in
2899 // case they contain any associated type projections. This process
2900 // can yield errors if the put in illegal associated types, like
2901 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2902 // report these errors right here; this doesn't actually feel
2903 // right to me, because constructing the environment feels like a
2904 // kind of a "idempotent" action, but I'm not sure where would be
2905 // a better place. In practice, we construct environments for
2906 // every fn once during type checking, and we'll abort if there
2907 // are any errors at that point, so after type checking you can be
2908 // sure that this will succeed without errors anyway.
2911 let unnormalized_env = ty::ParameterEnvironment {
2912 free_substs: free_substs,
2913 implicit_region_bound: ty::ReScope(free_id_outlive),
2914 caller_bounds: predicates,
2915 free_id_outlive: free_id_outlive,
2918 let cause = traits::ObligationCause::misc(span, free_id_outlive.node_id(&self.region_maps));
2919 traits::normalize_param_env_or_error(tcx, unnormalized_env, cause)
2922 pub fn is_method_call(self, expr_id: NodeId) -> bool {
2923 self.tables.borrow().method_map.contains_key(&MethodCall::expr(expr_id))
2926 pub fn is_overloaded_autoderef(self, expr_id: NodeId, autoderefs: u32) -> bool {
2927 self.tables.borrow().method_map.contains_key(&MethodCall::autoderef(expr_id,
2931 pub fn upvar_capture(self, upvar_id: ty::UpvarId) -> Option<ty::UpvarCapture> {
2932 Some(self.tables.borrow().upvar_capture_map.get(&upvar_id).unwrap().clone())
2935 pub fn visit_all_items_in_krate<V,F>(self,
2938 where F: FnMut(DefId) -> DepNode<DefId>, V: Visitor<'gcx>
2940 dep_graph::visit_all_items_in_krate(self.global_tcx(), dep_node_fn, visitor);
2943 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2944 /// with the name of the crate containing the impl.
2945 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, InternedString> {
2946 if impl_did.is_local() {
2947 let node_id = self.map.as_local_node_id(impl_did).unwrap();
2948 Ok(self.map.span(node_id))
2950 Err(self.sess.cstore.crate_name(impl_did.krate))
2955 /// The category of explicit self.
2956 #[derive(Clone, Copy, Eq, PartialEq, Debug)]
2957 pub enum ExplicitSelfCategory {
2960 ByReference(Region, hir::Mutability),
2964 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2965 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2966 F: FnOnce(&[hir::Freevar]) -> T,
2968 match self.freevars.borrow().get(&fid) {
2970 Some(d) => f(&d[..])