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::Variance::*;
12 pub use self::DtorKind::*;
13 pub use self::ImplOrTraitItemContainer::*;
14 pub use self::BorrowKind::*;
15 pub use self::ImplOrTraitItem::*;
16 pub use self::IntVarValue::*;
17 pub use self::LvaluePreference::*;
18 pub use self::fold::TypeFoldable;
20 use dep_graph::{self, DepNode};
21 use hir::map as ast_map;
23 use hir::def::{Def, PathResolution, ExportMap};
24 use hir::def_id::{CrateNum, DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
25 use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
26 use middle::region::{CodeExtent, ROOT_CODE_EXTENT};
29 use ty::subst::{Subst, Substs};
30 use ty::walk::TypeWalker;
31 use util::common::MemoizationMap;
32 use util::nodemap::NodeSet;
33 use util::nodemap::FnvHashMap;
35 use serialize::{self, Encodable, Encoder};
38 use std::hash::{Hash, Hasher};
43 use std::vec::IntoIter;
44 use syntax::ast::{self, Name, NodeId};
46 use syntax::parse::token::{self, InternedString};
47 use syntax_pos::{DUMMY_SP, Span};
49 use rustc_const_math::ConstInt;
52 use hir::intravisit::Visitor;
54 pub use self::sty::{Binder, DebruijnIndex};
55 pub use self::sty::{BuiltinBound, BuiltinBounds};
56 pub use self::sty::{BareFnTy, FnSig, PolyFnSig};
57 pub use self::sty::{ClosureTy, InferTy, ParamTy, ProjectionTy, TraitObject};
58 pub use self::sty::{ClosureSubsts, TypeAndMut};
59 pub use self::sty::{TraitRef, TypeVariants, PolyTraitRef};
60 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
61 pub use self::sty::{ExistentialProjection, PolyExistentialProjection};
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::InferTy::*;
67 pub use self::sty::Region::*;
68 pub use self::sty::TypeVariants::*;
70 pub use self::sty::BuiltinBound::Send as BoundSend;
71 pub use self::sty::BuiltinBound::Sized as BoundSized;
72 pub use self::sty::BuiltinBound::Copy as BoundCopy;
73 pub use self::sty::BuiltinBound::Sync as BoundSync;
75 pub use self::contents::TypeContents;
76 pub use self::context::{TyCtxt, tls};
77 pub use self::context::{CtxtArenas, Lift, Tables};
79 pub use self::trait_def::{TraitDef, TraitFlags};
102 mod structural_impls;
105 pub type Disr = ConstInt;
109 /// The complete set of all analyses described in this module. This is
110 /// produced by the driver and fed to trans and later passes.
112 pub struct CrateAnalysis<'a> {
113 pub export_map: ExportMap,
114 pub access_levels: middle::privacy::AccessLevels,
115 pub reachable: NodeSet,
117 pub glob_map: Option<hir::GlobMap>,
120 #[derive(Copy, Clone)]
127 pub fn is_present(&self) -> bool {
135 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
136 pub enum ImplOrTraitItemContainer {
137 TraitContainer(DefId),
138 ImplContainer(DefId),
141 impl ImplOrTraitItemContainer {
142 pub fn id(&self) -> DefId {
144 TraitContainer(id) => id,
145 ImplContainer(id) => id,
150 /// The "header" of an impl is everything outside the body: a Self type, a trait
151 /// ref (in the case of a trait impl), and a set of predicates (from the
152 /// bounds/where clauses).
153 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
154 pub struct ImplHeader<'tcx> {
155 pub impl_def_id: DefId,
156 pub self_ty: Ty<'tcx>,
157 pub trait_ref: Option<TraitRef<'tcx>>,
158 pub predicates: Vec<Predicate<'tcx>>,
161 impl<'a, 'gcx, 'tcx> ImplHeader<'tcx> {
162 pub fn with_fresh_ty_vars(selcx: &mut traits::SelectionContext<'a, 'gcx, 'tcx>,
166 let tcx = selcx.tcx();
167 let impl_substs = selcx.infcx().fresh_substs_for_item(DUMMY_SP, impl_def_id);
169 let header = ImplHeader {
170 impl_def_id: impl_def_id,
171 self_ty: tcx.lookup_item_type(impl_def_id).ty,
172 trait_ref: tcx.impl_trait_ref(impl_def_id),
173 predicates: tcx.lookup_predicates(impl_def_id).predicates
174 }.subst(tcx, impl_substs);
176 let traits::Normalized { value: mut header, obligations } =
177 traits::normalize(selcx, traits::ObligationCause::dummy(), &header);
179 header.predicates.extend(obligations.into_iter().map(|o| o.predicate));
185 pub enum ImplOrTraitItem<'tcx> {
186 ConstTraitItem(Rc<AssociatedConst<'tcx>>),
187 MethodTraitItem(Rc<Method<'tcx>>),
188 TypeTraitItem(Rc<AssociatedType<'tcx>>),
191 impl<'tcx> ImplOrTraitItem<'tcx> {
192 pub fn def(&self) -> Def {
194 ConstTraitItem(ref associated_const) => Def::AssociatedConst(associated_const.def_id),
195 MethodTraitItem(ref method) => Def::Method(method.def_id),
196 TypeTraitItem(ref ty) => Def::AssociatedTy(ty.def_id),
200 pub fn def_id(&self) -> DefId {
202 ConstTraitItem(ref associated_const) => associated_const.def_id,
203 MethodTraitItem(ref method) => method.def_id,
204 TypeTraitItem(ref associated_type) => associated_type.def_id,
208 pub fn name(&self) -> Name {
210 ConstTraitItem(ref associated_const) => associated_const.name,
211 MethodTraitItem(ref method) => method.name,
212 TypeTraitItem(ref associated_type) => associated_type.name,
216 pub fn vis(&self) -> Visibility {
218 ConstTraitItem(ref associated_const) => associated_const.vis,
219 MethodTraitItem(ref method) => method.vis,
220 TypeTraitItem(ref associated_type) => associated_type.vis,
224 pub fn container(&self) -> ImplOrTraitItemContainer {
226 ConstTraitItem(ref associated_const) => associated_const.container,
227 MethodTraitItem(ref method) => method.container,
228 TypeTraitItem(ref associated_type) => associated_type.container,
232 pub fn as_opt_method(&self) -> Option<Rc<Method<'tcx>>> {
234 MethodTraitItem(ref m) => Some((*m).clone()),
240 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
241 pub enum Visibility {
242 /// Visible everywhere (including in other crates).
244 /// Visible only in the given crate-local module.
246 /// Not visible anywhere in the local crate. This is the visibility of private external items.
250 pub trait NodeIdTree {
251 fn is_descendant_of(&self, node: NodeId, ancestor: NodeId) -> bool;
254 impl<'a> NodeIdTree for ast_map::Map<'a> {
255 fn is_descendant_of(&self, node: NodeId, ancestor: NodeId) -> bool {
256 let mut node_ancestor = node;
257 while node_ancestor != ancestor {
258 let node_ancestor_parent = self.get_module_parent(node_ancestor);
259 if node_ancestor_parent == node_ancestor {
262 node_ancestor = node_ancestor_parent;
269 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt) -> Self {
271 hir::Public => Visibility::Public,
272 hir::Visibility::Crate => Visibility::Restricted(ast::CRATE_NODE_ID),
273 hir::Visibility::Restricted { id, .. } => match tcx.expect_def(id) {
274 // If there is no resolution, `resolve` will have already reported an error, so
275 // assume that the visibility is public to avoid reporting more privacy errors.
276 Def::Err => Visibility::Public,
277 def => Visibility::Restricted(tcx.map.as_local_node_id(def.def_id()).unwrap()),
279 hir::Inherited => Visibility::Restricted(tcx.map.get_module_parent(id)),
283 /// Returns true if an item with this visibility is accessible from the given block.
284 pub fn is_accessible_from<T: NodeIdTree>(self, block: NodeId, tree: &T) -> bool {
285 let restriction = match self {
286 // Public items are visible everywhere.
287 Visibility::Public => return true,
288 // Private items from other crates are visible nowhere.
289 Visibility::PrivateExternal => return false,
290 // Restricted items are visible in an arbitrary local module.
291 Visibility::Restricted(module) => module,
294 tree.is_descendant_of(block, restriction)
297 /// Returns true if this visibility is at least as accessible as the given visibility
298 pub fn is_at_least<T: NodeIdTree>(self, vis: Visibility, tree: &T) -> bool {
299 let vis_restriction = match vis {
300 Visibility::Public => return self == Visibility::Public,
301 Visibility::PrivateExternal => return true,
302 Visibility::Restricted(module) => module,
305 self.is_accessible_from(vis_restriction, tree)
309 #[derive(Clone, Debug)]
310 pub struct Method<'tcx> {
312 pub generics: &'tcx Generics<'tcx>,
313 pub predicates: GenericPredicates<'tcx>,
314 pub fty: &'tcx BareFnTy<'tcx>,
315 pub explicit_self: ExplicitSelfCategory<'tcx>,
317 pub defaultness: hir::Defaultness,
320 pub container: ImplOrTraitItemContainer,
323 impl<'tcx> Method<'tcx> {
324 pub fn container_id(&self) -> DefId {
325 match self.container {
326 TraitContainer(id) => id,
327 ImplContainer(id) => id,
332 impl<'tcx> PartialEq for Method<'tcx> {
334 fn eq(&self, other: &Self) -> bool { self.def_id == other.def_id }
337 impl<'tcx> Eq for Method<'tcx> {}
339 impl<'tcx> Hash for Method<'tcx> {
341 fn hash<H: Hasher>(&self, s: &mut H) {
346 #[derive(Clone, Copy, Debug)]
347 pub struct AssociatedConst<'tcx> {
351 pub defaultness: hir::Defaultness,
353 pub container: ImplOrTraitItemContainer,
357 #[derive(Clone, Copy, Debug)]
358 pub struct AssociatedType<'tcx> {
360 pub ty: Option<Ty<'tcx>>,
362 pub defaultness: hir::Defaultness,
364 pub container: ImplOrTraitItemContainer,
367 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
369 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
370 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
371 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
372 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
375 #[derive(Clone, Copy, Debug, RustcDecodable, RustcEncodable)]
376 pub struct MethodCallee<'tcx> {
377 /// Impl method ID, for inherent methods, or trait method ID, otherwise.
380 pub substs: &'tcx Substs<'tcx>
383 /// With method calls, we store some extra information in
384 /// side tables (i.e method_map). We use
385 /// MethodCall as a key to index into these tables instead of
386 /// just directly using the expression's NodeId. The reason
387 /// for this being that we may apply adjustments (coercions)
388 /// with the resulting expression also needing to use the
389 /// side tables. The problem with this is that we don't
390 /// assign a separate NodeId to this new expression
391 /// and so it would clash with the base expression if both
392 /// needed to add to the side tables. Thus to disambiguate
393 /// we also keep track of whether there's an adjustment in
395 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
396 pub struct MethodCall {
402 pub fn expr(id: NodeId) -> MethodCall {
409 pub fn autoderef(expr_id: NodeId, autoderef: u32) -> MethodCall {
412 autoderef: 1 + autoderef
417 // maps from an expression id that corresponds to a method call to the details
418 // of the method to be invoked
419 pub type MethodMap<'tcx> = FnvHashMap<MethodCall, MethodCallee<'tcx>>;
421 // Contains information needed to resolve types and (in the future) look up
422 // the types of AST nodes.
423 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
424 pub struct CReaderCacheKey {
429 /// Describes the fragment-state associated with a NodeId.
431 /// Currently only unfragmented paths have entries in the table,
432 /// but longer-term this enum is expected to expand to also
433 /// include data for fragmented paths.
434 #[derive(Copy, Clone, Debug)]
435 pub enum FragmentInfo {
436 Moved { var: NodeId, move_expr: NodeId },
437 Assigned { var: NodeId, assign_expr: NodeId, assignee_id: NodeId },
440 // Flags that we track on types. These flags are propagated upwards
441 // through the type during type construction, so that we can quickly
442 // check whether the type has various kinds of types in it without
443 // recursing over the type itself.
445 flags TypeFlags: u32 {
446 const HAS_PARAMS = 1 << 0,
447 const HAS_SELF = 1 << 1,
448 const HAS_TY_INFER = 1 << 2,
449 const HAS_RE_INFER = 1 << 3,
450 const HAS_RE_SKOL = 1 << 4,
451 const HAS_RE_EARLY_BOUND = 1 << 5,
452 const HAS_FREE_REGIONS = 1 << 6,
453 const HAS_TY_ERR = 1 << 7,
454 const HAS_PROJECTION = 1 << 8,
455 const HAS_TY_CLOSURE = 1 << 9,
457 // true if there are "names" of types and regions and so forth
458 // that are local to a particular fn
459 const HAS_LOCAL_NAMES = 1 << 10,
461 // Present if the type belongs in a local type context.
462 // Only set for TyInfer other than Fresh.
463 const KEEP_IN_LOCAL_TCX = 1 << 11,
465 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
466 TypeFlags::HAS_SELF.bits |
467 TypeFlags::HAS_RE_EARLY_BOUND.bits,
469 // Flags representing the nominal content of a type,
470 // computed by FlagsComputation. If you add a new nominal
471 // flag, it should be added here too.
472 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
473 TypeFlags::HAS_SELF.bits |
474 TypeFlags::HAS_TY_INFER.bits |
475 TypeFlags::HAS_RE_INFER.bits |
476 TypeFlags::HAS_RE_EARLY_BOUND.bits |
477 TypeFlags::HAS_FREE_REGIONS.bits |
478 TypeFlags::HAS_TY_ERR.bits |
479 TypeFlags::HAS_PROJECTION.bits |
480 TypeFlags::HAS_TY_CLOSURE.bits |
481 TypeFlags::HAS_LOCAL_NAMES.bits |
482 TypeFlags::KEEP_IN_LOCAL_TCX.bits,
484 // Caches for type_is_sized, type_moves_by_default
485 const SIZEDNESS_CACHED = 1 << 16,
486 const IS_SIZED = 1 << 17,
487 const MOVENESS_CACHED = 1 << 18,
488 const MOVES_BY_DEFAULT = 1 << 19,
492 pub struct TyS<'tcx> {
493 pub sty: TypeVariants<'tcx>,
494 pub flags: Cell<TypeFlags>,
496 // the maximal depth of any bound regions appearing in this type.
500 impl<'tcx> PartialEq for TyS<'tcx> {
502 fn eq(&self, other: &TyS<'tcx>) -> bool {
503 // (self as *const _) == (other as *const _)
504 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
507 impl<'tcx> Eq for TyS<'tcx> {}
509 impl<'tcx> Hash for TyS<'tcx> {
510 fn hash<H: Hasher>(&self, s: &mut H) {
511 (self as *const TyS).hash(s)
515 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
517 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
518 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
520 /// A wrapper for slices with the additioanl invariant
521 /// that the slice is interned and no other slice with
522 /// the same contents can exist in the same context.
523 /// This means we can use pointer + length for both
524 /// equality comparisons and hashing.
525 #[derive(Debug, RustcEncodable)]
526 pub struct Slice<T>([T]);
528 impl<T> PartialEq for Slice<T> {
530 fn eq(&self, other: &Slice<T>) -> bool {
531 (&self.0 as *const [T]) == (&other.0 as *const [T])
534 impl<T> Eq for Slice<T> {}
536 impl<T> Hash for Slice<T> {
537 fn hash<H: Hasher>(&self, s: &mut H) {
538 (self.as_ptr(), self.len()).hash(s)
542 impl<T> Deref for Slice<T> {
544 fn deref(&self) -> &[T] {
549 impl<'a, T> IntoIterator for &'a Slice<T> {
551 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
552 fn into_iter(self) -> Self::IntoIter {
557 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {}
559 /// Upvars do not get their own node-id. Instead, we use the pair of
560 /// the original var id (that is, the root variable that is referenced
561 /// by the upvar) and the id of the closure expression.
562 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
565 pub closure_expr_id: NodeId,
568 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
569 pub enum BorrowKind {
570 /// Data must be immutable and is aliasable.
573 /// Data must be immutable but not aliasable. This kind of borrow
574 /// cannot currently be expressed by the user and is used only in
575 /// implicit closure bindings. It is needed when you the closure
576 /// is borrowing or mutating a mutable referent, e.g.:
578 /// let x: &mut isize = ...;
579 /// let y = || *x += 5;
581 /// If we were to try to translate this closure into a more explicit
582 /// form, we'd encounter an error with the code as written:
584 /// struct Env { x: & &mut isize }
585 /// let x: &mut isize = ...;
586 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
587 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
589 /// This is then illegal because you cannot mutate a `&mut` found
590 /// in an aliasable location. To solve, you'd have to translate with
591 /// an `&mut` borrow:
593 /// struct Env { x: & &mut isize }
594 /// let x: &mut isize = ...;
595 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
596 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
598 /// Now the assignment to `**env.x` is legal, but creating a
599 /// mutable pointer to `x` is not because `x` is not mutable. We
600 /// could fix this by declaring `x` as `let mut x`. This is ok in
601 /// user code, if awkward, but extra weird for closures, since the
602 /// borrow is hidden.
604 /// So we introduce a "unique imm" borrow -- the referent is
605 /// immutable, but not aliasable. This solves the problem. For
606 /// simplicity, we don't give users the way to express this
607 /// borrow, it's just used when translating closures.
610 /// Data is mutable and not aliasable.
614 /// Information describing the capture of an upvar. This is computed
615 /// during `typeck`, specifically by `regionck`.
616 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
617 pub enum UpvarCapture<'tcx> {
618 /// Upvar is captured by value. This is always true when the
619 /// closure is labeled `move`, but can also be true in other cases
620 /// depending on inference.
623 /// Upvar is captured by reference.
624 ByRef(UpvarBorrow<'tcx>),
627 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
628 pub struct UpvarBorrow<'tcx> {
629 /// The kind of borrow: by-ref upvars have access to shared
630 /// immutable borrows, which are not part of the normal language
632 pub kind: BorrowKind,
634 /// Region of the resulting reference.
635 pub region: &'tcx ty::Region,
638 pub type UpvarCaptureMap<'tcx> = FnvHashMap<UpvarId, UpvarCapture<'tcx>>;
640 #[derive(Copy, Clone)]
641 pub struct ClosureUpvar<'tcx> {
647 #[derive(Clone, Copy, PartialEq)]
648 pub enum IntVarValue {
650 UintType(ast::UintTy),
653 /// Default region to use for the bound of objects that are
654 /// supplied as the value for this type parameter. This is derived
655 /// from `T:'a` annotations appearing in the type definition. If
656 /// this is `None`, then the default is inherited from the
657 /// surrounding context. See RFC #599 for details.
658 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
659 pub enum ObjectLifetimeDefault<'tcx> {
660 /// Require an explicit annotation. Occurs when multiple
661 /// `T:'a` constraints are found.
664 /// Use the base default, typically 'static, but in a fn body it is a fresh variable
667 /// Use the given region as the default.
668 Specific(&'tcx Region),
671 #[derive(Clone, RustcEncodable, RustcDecodable)]
672 pub struct TypeParameterDef<'tcx> {
676 pub default_def_id: DefId, // for use in error reporing about defaults
677 pub default: Option<Ty<'tcx>>,
678 pub object_lifetime_default: ObjectLifetimeDefault<'tcx>,
681 #[derive(Clone, RustcEncodable, RustcDecodable)]
682 pub struct RegionParameterDef<'tcx> {
686 pub bounds: Vec<&'tcx ty::Region>,
689 impl<'tcx> RegionParameterDef<'tcx> {
690 pub fn to_early_bound_region(&self) -> ty::Region {
691 ty::ReEarlyBound(self.to_early_bound_region_data())
694 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
695 ty::EarlyBoundRegion {
701 pub fn to_bound_region(&self) -> ty::BoundRegion {
702 // this is an early bound region, so unaffected by #32330
703 ty::BoundRegion::BrNamed(self.def_id, self.name, Issue32330::WontChange)
707 /// Information about the formal type/lifetime parameters associated
708 /// with an item or method. Analogous to hir::Generics.
709 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
710 pub struct Generics<'tcx> {
711 pub parent: Option<DefId>,
712 pub parent_regions: u32,
713 pub parent_types: u32,
714 pub regions: Vec<RegionParameterDef<'tcx>>,
715 pub types: Vec<TypeParameterDef<'tcx>>,
719 impl<'tcx> Generics<'tcx> {
720 pub fn parent_count(&self) -> usize {
721 self.parent_regions as usize + self.parent_types as usize
724 pub fn own_count(&self) -> usize {
725 self.regions.len() + self.types.len()
728 pub fn count(&self) -> usize {
729 self.parent_count() + self.own_count()
733 /// Bounds on generics.
735 pub struct GenericPredicates<'tcx> {
736 pub parent: Option<DefId>,
737 pub predicates: Vec<Predicate<'tcx>>,
740 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
741 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
743 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
744 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
745 -> InstantiatedPredicates<'tcx> {
746 let mut instantiated = InstantiatedPredicates::empty();
747 self.instantiate_into(tcx, &mut instantiated, substs);
750 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
751 -> InstantiatedPredicates<'tcx> {
752 InstantiatedPredicates {
753 predicates: self.predicates.subst(tcx, substs)
757 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
758 instantiated: &mut InstantiatedPredicates<'tcx>,
759 substs: &Substs<'tcx>) {
760 if let Some(def_id) = self.parent {
761 tcx.lookup_predicates(def_id).instantiate_into(tcx, instantiated, substs);
763 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
766 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
767 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
768 -> InstantiatedPredicates<'tcx>
770 assert_eq!(self.parent, None);
771 InstantiatedPredicates {
772 predicates: self.predicates.iter().map(|pred| {
773 pred.subst_supertrait(tcx, poly_trait_ref)
779 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
780 pub enum Predicate<'tcx> {
781 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
782 /// the `Self` type of the trait reference and `A`, `B`, and `C`
783 /// would be the type parameters.
784 Trait(PolyTraitPredicate<'tcx>),
786 /// where `T1 == T2`.
787 Equate(PolyEquatePredicate<'tcx>),
790 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
793 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
795 /// where <T as TraitRef>::Name == X, approximately.
796 /// See `ProjectionPredicate` struct for details.
797 Projection(PolyProjectionPredicate<'tcx>),
800 WellFormed(Ty<'tcx>),
802 /// trait must be object-safe
805 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
806 /// for some substitutions `...` and T being a closure type.
807 /// Satisfied (or refuted) once we know the closure's kind.
808 ClosureKind(DefId, ClosureKind),
811 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
812 /// Performs a substitution suitable for going from a
813 /// poly-trait-ref to supertraits that must hold if that
814 /// poly-trait-ref holds. This is slightly different from a normal
815 /// substitution in terms of what happens with bound regions. See
816 /// lengthy comment below for details.
817 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
818 trait_ref: &ty::PolyTraitRef<'tcx>)
819 -> ty::Predicate<'tcx>
821 // The interaction between HRTB and supertraits is not entirely
822 // obvious. Let me walk you (and myself) through an example.
824 // Let's start with an easy case. Consider two traits:
826 // trait Foo<'a> : Bar<'a,'a> { }
827 // trait Bar<'b,'c> { }
829 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
830 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
831 // knew that `Foo<'x>` (for any 'x) then we also know that
832 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
833 // normal substitution.
835 // In terms of why this is sound, the idea is that whenever there
836 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
837 // holds. So if there is an impl of `T:Foo<'a>` that applies to
838 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
841 // Another example to be careful of is this:
843 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
844 // trait Bar1<'b,'c> { }
846 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
847 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
848 // reason is similar to the previous example: any impl of
849 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
850 // basically we would want to collapse the bound lifetimes from
851 // the input (`trait_ref`) and the supertraits.
853 // To achieve this in practice is fairly straightforward. Let's
854 // consider the more complicated scenario:
856 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
857 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
858 // where both `'x` and `'b` would have a DB index of 1.
859 // The substitution from the input trait-ref is therefore going to be
860 // `'a => 'x` (where `'x` has a DB index of 1).
861 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
862 // early-bound parameter and `'b' is a late-bound parameter with a
864 // - If we replace `'a` with `'x` from the input, it too will have
865 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
866 // just as we wanted.
868 // There is only one catch. If we just apply the substitution `'a
869 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
870 // adjust the DB index because we substituting into a binder (it
871 // tries to be so smart...) resulting in `for<'x> for<'b>
872 // Bar1<'x,'b>` (we have no syntax for this, so use your
873 // imagination). Basically the 'x will have DB index of 2 and 'b
874 // will have DB index of 1. Not quite what we want. So we apply
875 // the substitution to the *contents* of the trait reference,
876 // rather than the trait reference itself (put another way, the
877 // substitution code expects equal binding levels in the values
878 // from the substitution and the value being substituted into, and
879 // this trick achieves that).
881 let substs = &trait_ref.0.substs;
883 Predicate::Trait(ty::Binder(ref data)) =>
884 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
885 Predicate::Equate(ty::Binder(ref data)) =>
886 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
887 Predicate::RegionOutlives(ty::Binder(ref data)) =>
888 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
889 Predicate::TypeOutlives(ty::Binder(ref data)) =>
890 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
891 Predicate::Projection(ty::Binder(ref data)) =>
892 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
893 Predicate::WellFormed(data) =>
894 Predicate::WellFormed(data.subst(tcx, substs)),
895 Predicate::ObjectSafe(trait_def_id) =>
896 Predicate::ObjectSafe(trait_def_id),
897 Predicate::ClosureKind(closure_def_id, kind) =>
898 Predicate::ClosureKind(closure_def_id, kind),
903 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
904 pub struct TraitPredicate<'tcx> {
905 pub trait_ref: TraitRef<'tcx>
907 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
909 impl<'tcx> TraitPredicate<'tcx> {
910 pub fn def_id(&self) -> DefId {
911 self.trait_ref.def_id
914 /// Creates the dep-node for selecting/evaluating this trait reference.
915 fn dep_node(&self) -> DepNode<DefId> {
916 // Ideally, the dep-node would just have all the input types
917 // in it. But they are limited to including def-ids. So as an
918 // approximation we include the def-ids for all nominal types
919 // found somewhere. This means that we will e.g. conflate the
920 // dep-nodes for `u32: SomeTrait` and `u64: SomeTrait`, but we
921 // would have distinct dep-nodes for `Vec<u32>: SomeTrait`,
922 // `Rc<u32>: SomeTrait`, and `(Vec<u32>, Rc<u32>): SomeTrait`.
923 // Note that it's always sound to conflate dep-nodes, it just
924 // leads to more recompilation.
925 let def_ids: Vec<_> =
927 .flat_map(|t| t.walk())
928 .filter_map(|t| match t.sty {
929 ty::TyAdt(adt_def, _) =>
934 .chain(iter::once(self.def_id()))
936 DepNode::TraitSelect(def_ids)
939 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
940 self.trait_ref.input_types()
943 pub fn self_ty(&self) -> Ty<'tcx> {
944 self.trait_ref.self_ty()
948 impl<'tcx> PolyTraitPredicate<'tcx> {
949 pub fn def_id(&self) -> DefId {
950 // ok to skip binder since trait def-id does not care about regions
954 pub fn dep_node(&self) -> DepNode<DefId> {
955 // ok to skip binder since depnode does not care about regions
960 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
961 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
962 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
964 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
965 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
966 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
967 pub type PolyRegionOutlivesPredicate<'tcx> = PolyOutlivesPredicate<&'tcx ty::Region,
969 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, &'tcx ty::Region>;
971 /// This kind of predicate has no *direct* correspondent in the
972 /// syntax, but it roughly corresponds to the syntactic forms:
974 /// 1. `T : TraitRef<..., Item=Type>`
975 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
977 /// In particular, form #1 is "desugared" to the combination of a
978 /// normal trait predicate (`T : TraitRef<...>`) and one of these
979 /// predicates. Form #2 is a broader form in that it also permits
980 /// equality between arbitrary types. Processing an instance of Form
981 /// #2 eventually yields one of these `ProjectionPredicate`
982 /// instances to normalize the LHS.
983 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
984 pub struct ProjectionPredicate<'tcx> {
985 pub projection_ty: ProjectionTy<'tcx>,
989 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
991 impl<'tcx> PolyProjectionPredicate<'tcx> {
992 pub fn item_name(&self) -> Name {
993 self.0.projection_ty.item_name // safe to skip the binder to access a name
997 pub trait ToPolyTraitRef<'tcx> {
998 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1001 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1002 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1003 assert!(!self.has_escaping_regions());
1004 ty::Binder(self.clone())
1008 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1009 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1010 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1014 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
1015 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1016 // Note: unlike with TraitRef::to_poly_trait_ref(),
1017 // self.0.trait_ref is permitted to have escaping regions.
1018 // This is because here `self` has a `Binder` and so does our
1019 // return value, so we are preserving the number of binding
1021 ty::Binder(self.0.projection_ty.trait_ref)
1025 pub trait ToPredicate<'tcx> {
1026 fn to_predicate(&self) -> Predicate<'tcx>;
1029 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1030 fn to_predicate(&self) -> Predicate<'tcx> {
1031 // we're about to add a binder, so let's check that we don't
1032 // accidentally capture anything, or else that might be some
1033 // weird debruijn accounting.
1034 assert!(!self.has_escaping_regions());
1036 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
1037 trait_ref: self.clone()
1042 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1043 fn to_predicate(&self) -> Predicate<'tcx> {
1044 ty::Predicate::Trait(self.to_poly_trait_predicate())
1048 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
1049 fn to_predicate(&self) -> Predicate<'tcx> {
1050 Predicate::Equate(self.clone())
1054 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1055 fn to_predicate(&self) -> Predicate<'tcx> {
1056 Predicate::RegionOutlives(self.clone())
1060 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1061 fn to_predicate(&self) -> Predicate<'tcx> {
1062 Predicate::TypeOutlives(self.clone())
1066 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1067 fn to_predicate(&self) -> Predicate<'tcx> {
1068 Predicate::Projection(self.clone())
1072 impl<'tcx> Predicate<'tcx> {
1073 /// Iterates over the types in this predicate. Note that in all
1074 /// cases this is skipping over a binder, so late-bound regions
1075 /// with depth 0 are bound by the predicate.
1076 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1077 let vec: Vec<_> = match *self {
1078 ty::Predicate::Trait(ref data) => {
1079 data.skip_binder().input_types().collect()
1081 ty::Predicate::Equate(ty::Binder(ref data)) => {
1082 vec![data.0, data.1]
1084 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
1087 ty::Predicate::RegionOutlives(..) => {
1090 ty::Predicate::Projection(ref data) => {
1091 let trait_inputs = data.0.projection_ty.trait_ref.input_types();
1092 trait_inputs.chain(Some(data.0.ty)).collect()
1094 ty::Predicate::WellFormed(data) => {
1097 ty::Predicate::ObjectSafe(_trait_def_id) => {
1100 ty::Predicate::ClosureKind(_closure_def_id, _kind) => {
1105 // The only reason to collect into a vector here is that I was
1106 // too lazy to make the full (somewhat complicated) iterator
1107 // type that would be needed here. But I wanted this fn to
1108 // return an iterator conceptually, rather than a `Vec`, so as
1109 // to be closer to `Ty::walk`.
1113 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1115 Predicate::Trait(ref t) => {
1116 Some(t.to_poly_trait_ref())
1118 Predicate::Projection(..) |
1119 Predicate::Equate(..) |
1120 Predicate::RegionOutlives(..) |
1121 Predicate::WellFormed(..) |
1122 Predicate::ObjectSafe(..) |
1123 Predicate::ClosureKind(..) |
1124 Predicate::TypeOutlives(..) => {
1131 /// Represents the bounds declared on a particular set of type
1132 /// parameters. Should eventually be generalized into a flag list of
1133 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1134 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1135 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1136 /// the `GenericPredicates` are expressed in terms of the bound type
1137 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1138 /// represented a set of bounds for some particular instantiation,
1139 /// meaning that the generic parameters have been substituted with
1144 /// struct Foo<T,U:Bar<T>> { ... }
1146 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1147 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1148 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1149 /// [usize:Bar<isize>]]`.
1151 pub struct InstantiatedPredicates<'tcx> {
1152 pub predicates: Vec<Predicate<'tcx>>,
1155 impl<'tcx> InstantiatedPredicates<'tcx> {
1156 pub fn empty() -> InstantiatedPredicates<'tcx> {
1157 InstantiatedPredicates { predicates: vec![] }
1160 pub fn is_empty(&self) -> bool {
1161 self.predicates.is_empty()
1165 impl<'tcx> TraitRef<'tcx> {
1166 pub fn new(def_id: DefId, substs: &'tcx Substs<'tcx>) -> TraitRef<'tcx> {
1167 TraitRef { def_id: def_id, substs: substs }
1170 pub fn self_ty(&self) -> Ty<'tcx> {
1171 self.substs.type_at(0)
1174 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
1175 // Select only the "input types" from a trait-reference. For
1176 // now this is all the types that appear in the
1177 // trait-reference, but it should eventually exclude
1178 // associated types.
1183 /// When type checking, we use the `ParameterEnvironment` to track
1184 /// details about the type/lifetime parameters that are in scope.
1185 /// It primarily stores the bounds information.
1187 /// Note: This information might seem to be redundant with the data in
1188 /// `tcx.ty_param_defs`, but it is not. That table contains the
1189 /// parameter definitions from an "outside" perspective, but this
1190 /// struct will contain the bounds for a parameter as seen from inside
1191 /// the function body. Currently the only real distinction is that
1192 /// bound lifetime parameters are replaced with free ones, but in the
1193 /// future I hope to refine the representation of types so as to make
1194 /// more distinctions clearer.
1196 pub struct ParameterEnvironment<'tcx> {
1197 /// See `construct_free_substs` for details.
1198 pub free_substs: &'tcx Substs<'tcx>,
1200 /// Each type parameter has an implicit region bound that
1201 /// indicates it must outlive at least the function body (the user
1202 /// may specify stronger requirements). This field indicates the
1203 /// region of the callee.
1204 pub implicit_region_bound: &'tcx ty::Region,
1206 /// Obligations that the caller must satisfy. This is basically
1207 /// the set of bounds on the in-scope type parameters, translated
1208 /// into Obligations, and elaborated and normalized.
1209 pub caller_bounds: Vec<ty::Predicate<'tcx>>,
1211 /// Scope that is attached to free regions for this scope. This
1212 /// is usually the id of the fn body, but for more abstract scopes
1213 /// like structs we often use the node-id of the struct.
1215 /// FIXME(#3696). It would be nice to refactor so that free
1216 /// regions don't have this implicit scope and instead introduce
1217 /// relationships in the environment.
1218 pub free_id_outlive: CodeExtent,
1221 impl<'a, 'tcx> ParameterEnvironment<'tcx> {
1222 pub fn with_caller_bounds(&self,
1223 caller_bounds: Vec<ty::Predicate<'tcx>>)
1224 -> ParameterEnvironment<'tcx>
1226 ParameterEnvironment {
1227 free_substs: self.free_substs,
1228 implicit_region_bound: self.implicit_region_bound,
1229 caller_bounds: caller_bounds,
1230 free_id_outlive: self.free_id_outlive,
1234 /// Construct a parameter environment given an item, impl item, or trait item
1235 pub fn for_item(tcx: TyCtxt<'a, 'tcx, 'tcx>, id: NodeId)
1236 -> ParameterEnvironment<'tcx> {
1237 match tcx.map.find(id) {
1238 Some(ast_map::NodeImplItem(ref impl_item)) => {
1239 match impl_item.node {
1240 hir::ImplItemKind::Type(_) | hir::ImplItemKind::Const(..) => {
1241 // associated types don't have their own entry (for some reason),
1242 // so for now just grab environment for the impl
1243 let impl_id = tcx.map.get_parent(id);
1244 let impl_def_id = tcx.map.local_def_id(impl_id);
1245 tcx.construct_parameter_environment(impl_item.span,
1247 tcx.region_maps.item_extent(id))
1249 hir::ImplItemKind::Method(_, ref body) => {
1250 let method_def_id = tcx.map.local_def_id(id);
1251 match tcx.impl_or_trait_item(method_def_id) {
1252 MethodTraitItem(ref method_ty) => {
1253 tcx.construct_parameter_environment(
1256 tcx.region_maps.call_site_extent(id, body.id))
1259 bug!("ParameterEnvironment::for_item(): \
1260 got non-method item from impl method?!")
1266 Some(ast_map::NodeTraitItem(trait_item)) => {
1267 match trait_item.node {
1268 hir::TypeTraitItem(..) | hir::ConstTraitItem(..) => {
1269 // associated types don't have their own entry (for some reason),
1270 // so for now just grab environment for the trait
1271 let trait_id = tcx.map.get_parent(id);
1272 let trait_def_id = tcx.map.local_def_id(trait_id);
1273 tcx.construct_parameter_environment(trait_item.span,
1275 tcx.region_maps.item_extent(id))
1277 hir::MethodTraitItem(_, ref body) => {
1278 // Use call-site for extent (unless this is a
1279 // trait method with no default; then fallback
1280 // to the method id).
1281 let method_def_id = tcx.map.local_def_id(id);
1282 match tcx.impl_or_trait_item(method_def_id) {
1283 MethodTraitItem(ref method_ty) => {
1284 let extent = if let Some(ref body) = *body {
1285 // default impl: use call_site extent as free_id_outlive bound.
1286 tcx.region_maps.call_site_extent(id, body.id)
1288 // no default impl: use item extent as free_id_outlive bound.
1289 tcx.region_maps.item_extent(id)
1291 tcx.construct_parameter_environment(
1297 bug!("ParameterEnvironment::for_item(): \
1298 got non-method item from provided \
1305 Some(ast_map::NodeItem(item)) => {
1307 hir::ItemFn(.., ref body) => {
1308 // We assume this is a function.
1309 let fn_def_id = tcx.map.local_def_id(id);
1311 tcx.construct_parameter_environment(
1314 tcx.region_maps.call_site_extent(id, body.id))
1317 hir::ItemStruct(..) |
1318 hir::ItemUnion(..) |
1321 hir::ItemConst(..) |
1322 hir::ItemStatic(..) => {
1323 let def_id = tcx.map.local_def_id(id);
1324 tcx.construct_parameter_environment(item.span,
1326 tcx.region_maps.item_extent(id))
1328 hir::ItemTrait(..) => {
1329 let def_id = tcx.map.local_def_id(id);
1330 tcx.construct_parameter_environment(item.span,
1332 tcx.region_maps.item_extent(id))
1335 span_bug!(item.span,
1336 "ParameterEnvironment::for_item():
1337 can't create a parameter \
1338 environment for this kind of item")
1342 Some(ast_map::NodeExpr(expr)) => {
1343 // This is a convenience to allow closures to work.
1344 if let hir::ExprClosure(..) = expr.node {
1345 ParameterEnvironment::for_item(tcx, tcx.map.get_parent(id))
1347 tcx.empty_parameter_environment()
1350 Some(ast_map::NodeForeignItem(item)) => {
1351 let def_id = tcx.map.local_def_id(id);
1352 tcx.construct_parameter_environment(item.span,
1357 bug!("ParameterEnvironment::from_item(): \
1358 `{}` is not an item",
1359 tcx.map.node_to_string(id))
1365 /// A "type scheme", in ML terminology, is a type combined with some
1366 /// set of generic types that the type is, well, generic over. In Rust
1367 /// terms, it is the "type" of a fn item or struct -- this type will
1368 /// include various generic parameters that must be substituted when
1369 /// the item/struct is referenced. That is called converting the type
1370 /// scheme to a monotype.
1372 /// - `generics`: the set of type parameters and their bounds
1373 /// - `ty`: the base types, which may reference the parameters defined
1376 /// Note that TypeSchemes are also sometimes called "polytypes" (and
1377 /// in fact this struct used to carry that name, so you may find some
1378 /// stray references in a comment or something). We try to reserve the
1379 /// "poly" prefix to refer to higher-ranked things, as in
1382 /// Note that each item also comes with predicates, see
1383 /// `lookup_predicates`.
1384 #[derive(Clone, Debug)]
1385 pub struct TypeScheme<'tcx> {
1386 pub generics: &'tcx Generics<'tcx>,
1391 flags AdtFlags: u32 {
1392 const NO_ADT_FLAGS = 0,
1393 const IS_ENUM = 1 << 0,
1394 const IS_DTORCK = 1 << 1, // is this a dtorck type?
1395 const IS_DTORCK_VALID = 1 << 2,
1396 const IS_PHANTOM_DATA = 1 << 3,
1397 const IS_SIMD = 1 << 4,
1398 const IS_FUNDAMENTAL = 1 << 5,
1399 const IS_UNION = 1 << 6,
1403 pub type AdtDef<'tcx> = &'tcx AdtDefData<'tcx, 'static>;
1404 pub type VariantDef<'tcx> = &'tcx VariantDefData<'tcx, 'static>;
1405 pub type FieldDef<'tcx> = &'tcx FieldDefData<'tcx, 'static>;
1407 // See comment on AdtDefData for explanation
1408 pub type AdtDefMaster<'tcx> = &'tcx AdtDefData<'tcx, 'tcx>;
1409 pub type VariantDefMaster<'tcx> = &'tcx VariantDefData<'tcx, 'tcx>;
1410 pub type FieldDefMaster<'tcx> = &'tcx FieldDefData<'tcx, 'tcx>;
1412 pub struct VariantDefData<'tcx, 'container: 'tcx> {
1413 /// The variant's DefId. If this is a tuple-like struct,
1414 /// this is the DefId of the struct's ctor.
1416 pub name: Name, // struct's name if this is a struct
1418 pub fields: Vec<FieldDefData<'tcx, 'container>>,
1419 pub kind: VariantKind,
1422 pub struct FieldDefData<'tcx, 'container: 'tcx> {
1423 /// The field's DefId. NOTE: the fields of tuple-like enum variants
1424 /// are not real items, and don't have entries in tcache etc.
1427 pub vis: Visibility,
1428 /// TyIVar is used here to allow for variance (see the doc at
1431 /// Note: direct accesses to `ty` must also add dep edges.
1432 ty: ivar::TyIVar<'tcx, 'container>
1435 /// The definition of an abstract data type - a struct or enum.
1437 /// These are all interned (by intern_adt_def) into the adt_defs
1440 /// Because of the possibility of nested tcx-s, this type
1441 /// needs 2 lifetimes: the traditional variant lifetime ('tcx)
1442 /// bounding the lifetime of the inner types is of course necessary.
1443 /// However, it is not sufficient - types from a child tcx must
1444 /// not be leaked into the master tcx by being stored in an AdtDefData.
1446 /// The 'container lifetime ensures that by outliving the container
1447 /// tcx and preventing shorter-lived types from being inserted. When
1448 /// write access is not needed, the 'container lifetime can be
1449 /// erased to 'static, which can be done by the AdtDef wrapper.
1450 pub struct AdtDefData<'tcx, 'container: 'tcx> {
1452 pub variants: Vec<VariantDefData<'tcx, 'container>>,
1453 destructor: Cell<Option<DefId>>,
1454 flags: Cell<AdtFlags>,
1455 sized_constraint: ivar::TyIVar<'tcx, 'container>,
1458 impl<'tcx, 'container> PartialEq for AdtDefData<'tcx, 'container> {
1459 // AdtDefData are always interned and this is part of TyS equality
1461 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1464 impl<'tcx, 'container> Eq for AdtDefData<'tcx, 'container> {}
1466 impl<'tcx, 'container> Hash for AdtDefData<'tcx, 'container> {
1468 fn hash<H: Hasher>(&self, s: &mut H) {
1469 (self as *const AdtDefData).hash(s)
1473 impl<'tcx> serialize::UseSpecializedEncodable for AdtDef<'tcx> {
1474 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1479 impl<'tcx> serialize::UseSpecializedDecodable for AdtDef<'tcx> {}
1481 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1482 pub enum AdtKind { Struct, Union, Enum }
1484 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1485 pub enum VariantKind { Struct, Tuple, Unit }
1488 pub fn from_variant_data(vdata: &hir::VariantData) -> Self {
1490 hir::VariantData::Struct(..) => VariantKind::Struct,
1491 hir::VariantData::Tuple(..) => VariantKind::Tuple,
1492 hir::VariantData::Unit(..) => VariantKind::Unit,
1497 impl<'a, 'gcx, 'tcx, 'container> AdtDefData<'gcx, 'container> {
1498 fn new(tcx: TyCtxt<'a, 'gcx, 'tcx>,
1501 variants: Vec<VariantDefData<'gcx, 'container>>) -> Self {
1502 let mut flags = AdtFlags::NO_ADT_FLAGS;
1503 let attrs = tcx.get_attrs(did);
1504 if attr::contains_name(&attrs, "fundamental") {
1505 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1507 if tcx.lookup_simd(did) {
1508 flags = flags | AdtFlags::IS_SIMD;
1510 if Some(did) == tcx.lang_items.phantom_data() {
1511 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1514 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
1515 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
1516 AdtKind::Struct => {}
1521 flags: Cell::new(flags),
1522 destructor: Cell::new(None),
1523 sized_constraint: ivar::TyIVar::new(),
1527 fn calculate_dtorck(&'gcx self, tcx: TyCtxt) {
1528 if tcx.is_adt_dtorck(self) {
1529 self.flags.set(self.flags.get() | AdtFlags::IS_DTORCK);
1531 self.flags.set(self.flags.get() | AdtFlags::IS_DTORCK_VALID)
1535 pub fn is_struct(&self) -> bool {
1536 !self.is_union() && !self.is_enum()
1540 pub fn is_union(&self) -> bool {
1541 self.flags.get().intersects(AdtFlags::IS_UNION)
1545 pub fn is_enum(&self) -> bool {
1546 self.flags.get().intersects(AdtFlags::IS_ENUM)
1549 /// Returns the kind of the ADT - Struct or Enum.
1551 pub fn adt_kind(&self) -> AdtKind {
1554 } else if self.is_union() {
1561 pub fn descr(&self) -> &'static str {
1562 match self.adt_kind() {
1563 AdtKind::Struct => "struct",
1564 AdtKind::Union => "union",
1565 AdtKind::Enum => "enum",
1569 pub fn variant_descr(&self) -> &'static str {
1570 match self.adt_kind() {
1571 AdtKind::Struct => "struct",
1572 AdtKind::Union => "union",
1573 AdtKind::Enum => "variant",
1577 /// Returns whether this is a dtorck type. If this returns
1578 /// true, this type being safe for destruction requires it to be
1579 /// alive; Otherwise, only the contents are required to be.
1581 pub fn is_dtorck(&'gcx self, tcx: TyCtxt) -> bool {
1582 if !self.flags.get().intersects(AdtFlags::IS_DTORCK_VALID) {
1583 self.calculate_dtorck(tcx)
1585 self.flags.get().intersects(AdtFlags::IS_DTORCK)
1588 /// Returns whether this type is #[fundamental] for the purposes
1589 /// of coherence checking.
1591 pub fn is_fundamental(&self) -> bool {
1592 self.flags.get().intersects(AdtFlags::IS_FUNDAMENTAL)
1596 pub fn is_simd(&self) -> bool {
1597 self.flags.get().intersects(AdtFlags::IS_SIMD)
1600 /// Returns true if this is PhantomData<T>.
1602 pub fn is_phantom_data(&self) -> bool {
1603 self.flags.get().intersects(AdtFlags::IS_PHANTOM_DATA)
1606 /// Returns whether this type has a destructor.
1607 pub fn has_dtor(&self) -> bool {
1608 self.dtor_kind().is_present()
1611 /// Asserts this is a struct and returns the struct's unique
1613 pub fn struct_variant(&self) -> &VariantDefData<'gcx, 'container> {
1614 assert!(!self.is_enum());
1619 pub fn type_scheme(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> TypeScheme<'gcx> {
1620 tcx.lookup_item_type(self.did)
1624 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
1625 tcx.lookup_predicates(self.did)
1628 /// Returns an iterator over all fields contained
1631 pub fn all_fields(&self) ->
1633 slice::Iter<VariantDefData<'gcx, 'container>>,
1634 slice::Iter<FieldDefData<'gcx, 'container>>,
1635 for<'s> fn(&'s VariantDefData<'gcx, 'container>)
1636 -> slice::Iter<'s, FieldDefData<'gcx, 'container>>
1638 self.variants.iter().flat_map(VariantDefData::fields_iter)
1642 pub fn is_empty(&self) -> bool {
1643 self.variants.is_empty()
1647 pub fn is_univariant(&self) -> bool {
1648 self.variants.len() == 1
1651 pub fn is_payloadfree(&self) -> bool {
1652 !self.variants.is_empty() &&
1653 self.variants.iter().all(|v| v.fields.is_empty())
1656 pub fn variant_with_id(&self, vid: DefId) -> &VariantDefData<'gcx, 'container> {
1659 .find(|v| v.did == vid)
1660 .expect("variant_with_id: unknown variant")
1663 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1666 .position(|v| v.did == vid)
1667 .expect("variant_index_with_id: unknown variant")
1670 pub fn variant_of_def(&self, def: Def) -> &VariantDefData<'gcx, 'container> {
1672 Def::Variant(vid) => self.variant_with_id(vid),
1673 Def::Struct(..) | Def::Union(..) |
1674 Def::TyAlias(..) | Def::AssociatedTy(..) => self.struct_variant(),
1675 _ => bug!("unexpected def {:?} in variant_of_def", def)
1679 pub fn destructor(&self) -> Option<DefId> {
1680 self.destructor.get()
1683 pub fn set_destructor(&self, dtor: DefId) {
1684 self.destructor.set(Some(dtor));
1687 pub fn dtor_kind(&self) -> DtorKind {
1688 match self.destructor.get() {
1689 Some(_) => TraitDtor,
1695 impl<'a, 'gcx, 'tcx, 'container> AdtDefData<'tcx, 'container> {
1696 /// Returns a simpler type such that `Self: Sized` if and only
1697 /// if that type is Sized, or `TyErr` if this type is recursive.
1699 /// HACK: instead of returning a list of types, this function can
1700 /// return a tuple. In that case, the result is Sized only if
1701 /// all elements of the tuple are Sized.
1703 /// This is generally the `struct_tail` if this is a struct, or a
1704 /// tuple of them if this is an enum.
1706 /// Oddly enough, checking that the sized-constraint is Sized is
1707 /// actually more expressive than checking all members:
1708 /// the Sized trait is inductive, so an associated type that references
1709 /// Self would prevent its containing ADT from being Sized.
1711 /// Due to normalization being eager, this applies even if
1712 /// the associated type is behind a pointer, e.g. issue #31299.
1713 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Ty<'tcx> {
1714 match self.sized_constraint.get(DepNode::SizedConstraint(self.did)) {
1716 let global_tcx = tcx.global_tcx();
1717 let this = global_tcx.lookup_adt_def_master(self.did);
1718 this.calculate_sized_constraint_inner(global_tcx, &mut Vec::new());
1719 self.sized_constraint(tcx)
1726 impl<'a, 'tcx> AdtDefData<'tcx, 'tcx> {
1727 /// Calculates the Sized-constraint.
1729 /// As the Sized-constraint of enums can be a *set* of types,
1730 /// the Sized-constraint may need to be a set also. Because introducing
1731 /// a new type of IVar is currently a complex affair, the Sized-constraint
1734 /// In fact, there are only a few options for the constraint:
1735 /// - `bool`, if the type is always Sized
1736 /// - an obviously-unsized type
1737 /// - a type parameter or projection whose Sizedness can't be known
1738 /// - a tuple of type parameters or projections, if there are multiple
1740 /// - a TyError, if a type contained itself. The representability
1741 /// check should catch this case.
1742 fn calculate_sized_constraint_inner(&'tcx self,
1743 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1744 stack: &mut Vec<AdtDefMaster<'tcx>>)
1746 let dep_node = || DepNode::SizedConstraint(self.did);
1748 // Follow the memoization pattern: push the computation of
1749 // DepNode::SizedConstraint as our current task.
1750 let _task = tcx.dep_graph.in_task(dep_node());
1751 if self.sized_constraint.untracked_get().is_some() {
1753 // can skip the dep-graph read since we just pushed the task
1757 if stack.contains(&self) {
1758 debug!("calculate_sized_constraint: {:?} is recursive", self);
1759 // This should be reported as an error by `check_representable`.
1761 // Consider the type as Sized in the meanwhile to avoid
1763 self.sized_constraint.fulfill(dep_node(), tcx.types.err);
1770 self.variants.iter().flat_map(|v| {
1773 self.sized_constraint_for_ty(tcx, stack, f.unsubst_ty())
1776 let self_ = stack.pop().unwrap();
1777 assert_eq!(self_, self);
1779 let ty = match tys.len() {
1780 _ if tys.references_error() => tcx.types.err,
1781 0 => tcx.types.bool,
1783 _ => tcx.mk_tup(tys)
1786 match self.sized_constraint.get(dep_node()) {
1788 debug!("calculate_sized_constraint: {:?} recurred", self);
1789 assert_eq!(old_ty, tcx.types.err)
1792 debug!("calculate_sized_constraint: {:?} => {:?}", self, ty);
1793 self.sized_constraint.fulfill(dep_node(), ty)
1798 fn sized_constraint_for_ty(
1800 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1801 stack: &mut Vec<AdtDefMaster<'tcx>>,
1803 ) -> Vec<Ty<'tcx>> {
1804 let result = match ty.sty {
1805 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
1806 TyBox(..) | TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
1807 TyArray(..) | TyClosure(..) | TyNever => {
1811 TyStr | TyTrait(..) | TySlice(_) | TyError => {
1812 // these are never sized - return the target type
1816 TyTuple(ref tys) => {
1819 Some(ty) => self.sized_constraint_for_ty(tcx, stack, ty)
1823 TyAdt(adt, substs) => {
1825 let adt = tcx.lookup_adt_def_master(adt.did);
1826 adt.calculate_sized_constraint_inner(tcx, stack);
1828 adt.sized_constraint
1829 .unwrap(DepNode::SizedConstraint(adt.did))
1830 .subst(tcx, substs);
1831 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
1833 if let ty::TyTuple(ref tys) = adt_ty.sty {
1834 tys.iter().flat_map(|ty| {
1835 self.sized_constraint_for_ty(tcx, stack, ty)
1838 self.sized_constraint_for_ty(tcx, stack, adt_ty)
1842 TyProjection(..) | TyAnon(..) => {
1843 // must calculate explicitly.
1844 // FIXME: consider special-casing always-Sized projections
1849 // perf hack: if there is a `T: Sized` bound, then
1850 // we know that `T` is Sized and do not need to check
1853 let sized_trait = match tcx.lang_items.sized_trait() {
1855 _ => return vec![ty]
1857 let sized_predicate = Binder(TraitRef {
1858 def_id: sized_trait,
1859 substs: Substs::new_trait(tcx, ty, &[])
1861 let predicates = tcx.lookup_predicates(self.did).predicates;
1862 if predicates.into_iter().any(|p| p == sized_predicate) {
1870 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
1874 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
1879 impl<'tcx, 'container> VariantDefData<'tcx, 'container> {
1881 fn fields_iter(&self) -> slice::Iter<FieldDefData<'tcx, 'container>> {
1886 pub fn find_field_named(&self,
1888 -> Option<&FieldDefData<'tcx, 'container>> {
1889 self.fields.iter().find(|f| f.name == name)
1893 pub fn index_of_field_named(&self,
1896 self.fields.iter().position(|f| f.name == name)
1900 pub fn field_named(&self, name: ast::Name) -> &FieldDefData<'tcx, 'container> {
1901 self.find_field_named(name).unwrap()
1905 impl<'a, 'gcx, 'tcx, 'container> FieldDefData<'tcx, 'container> {
1906 pub fn new(did: DefId,
1908 vis: Visibility) -> Self {
1913 ty: ivar::TyIVar::new()
1917 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1918 self.unsubst_ty().subst(tcx, subst)
1921 pub fn unsubst_ty(&self) -> Ty<'tcx> {
1922 self.ty.unwrap(DepNode::FieldTy(self.did))
1925 pub fn fulfill_ty(&self, ty: Ty<'container>) {
1926 self.ty.fulfill(DepNode::FieldTy(self.did), ty);
1930 /// Records the substitutions used to translate the polytype for an
1931 /// item into the monotype of an item reference.
1932 #[derive(Clone, RustcEncodable, RustcDecodable)]
1933 pub struct ItemSubsts<'tcx> {
1934 pub substs: &'tcx Substs<'tcx>,
1937 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1938 pub enum ClosureKind {
1939 // Warning: Ordering is significant here! The ordering is chosen
1940 // because the trait Fn is a subtrait of FnMut and so in turn, and
1941 // hence we order it so that Fn < FnMut < FnOnce.
1947 impl<'a, 'tcx> ClosureKind {
1948 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
1949 let result = match *self {
1950 ClosureKind::Fn => tcx.lang_items.require(FnTraitLangItem),
1951 ClosureKind::FnMut => {
1952 tcx.lang_items.require(FnMutTraitLangItem)
1954 ClosureKind::FnOnce => {
1955 tcx.lang_items.require(FnOnceTraitLangItem)
1959 Ok(trait_did) => trait_did,
1960 Err(err) => tcx.sess.fatal(&err[..]),
1964 /// True if this a type that impls this closure kind
1965 /// must also implement `other`.
1966 pub fn extends(self, other: ty::ClosureKind) -> bool {
1967 match (self, other) {
1968 (ClosureKind::Fn, ClosureKind::Fn) => true,
1969 (ClosureKind::Fn, ClosureKind::FnMut) => true,
1970 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
1971 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
1972 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
1973 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
1979 impl<'tcx> TyS<'tcx> {
1980 /// Iterator that walks `self` and any types reachable from
1981 /// `self`, in depth-first order. Note that just walks the types
1982 /// that appear in `self`, it does not descend into the fields of
1983 /// structs or variants. For example:
1986 /// isize => { isize }
1987 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
1988 /// [isize] => { [isize], isize }
1990 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
1991 TypeWalker::new(self)
1994 /// Iterator that walks the immediate children of `self`. Hence
1995 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
1996 /// (but not `i32`, like `walk`).
1997 pub fn walk_shallow(&'tcx self) -> IntoIter<Ty<'tcx>> {
1998 walk::walk_shallow(self)
2001 /// Walks `ty` and any types appearing within `ty`, invoking the
2002 /// callback `f` on each type. If the callback returns false, then the
2003 /// children of the current type are ignored.
2005 /// Note: prefer `ty.walk()` where possible.
2006 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2007 where F : FnMut(Ty<'tcx>) -> bool
2009 let mut walker = self.walk();
2010 while let Some(ty) = walker.next() {
2012 walker.skip_current_subtree();
2018 impl<'tcx> ItemSubsts<'tcx> {
2019 pub fn is_noop(&self) -> bool {
2020 self.substs.is_noop()
2024 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
2025 pub enum LvaluePreference {
2030 impl LvaluePreference {
2031 pub fn from_mutbl(m: hir::Mutability) -> Self {
2033 hir::MutMutable => PreferMutLvalue,
2034 hir::MutImmutable => NoPreference,
2039 /// Helper for looking things up in the various maps that are populated during
2040 /// typeck::collect (e.g., `tcx.impl_or_trait_items`, `tcx.tcache`, etc). All of
2041 /// these share the pattern that if the id is local, it should have been loaded
2042 /// into the map by the `typeck::collect` phase. If the def-id is external,
2043 /// then we have to go consult the crate loading code (and cache the result for
2045 fn lookup_locally_or_in_crate_store<M, F>(descr: &str,
2050 M: MemoizationMap<Key=DefId>,
2051 F: FnOnce() -> M::Value,
2053 map.memoize(def_id, || {
2054 if def_id.is_local() {
2055 bug!("No def'n found for {:?} in tcx.{}", def_id, descr);
2062 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2064 hir::MutMutable => MutBorrow,
2065 hir::MutImmutable => ImmBorrow,
2069 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2070 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2071 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2073 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2075 MutBorrow => hir::MutMutable,
2076 ImmBorrow => hir::MutImmutable,
2078 // We have no type corresponding to a unique imm borrow, so
2079 // use `&mut`. It gives all the capabilities of an `&uniq`
2080 // and hence is a safe "over approximation".
2081 UniqueImmBorrow => hir::MutMutable,
2085 pub fn to_user_str(&self) -> &'static str {
2087 MutBorrow => "mutable",
2088 ImmBorrow => "immutable",
2089 UniqueImmBorrow => "uniquely immutable",
2094 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2095 pub fn node_id_to_type(self, id: NodeId) -> Ty<'gcx> {
2096 match self.node_id_to_type_opt(id) {
2098 None => bug!("node_id_to_type: no type for node `{}`",
2099 self.map.node_to_string(id))
2103 pub fn node_id_to_type_opt(self, id: NodeId) -> Option<Ty<'gcx>> {
2104 self.tables.borrow().node_types.get(&id).cloned()
2107 pub fn node_id_item_substs(self, id: NodeId) -> ItemSubsts<'gcx> {
2108 match self.tables.borrow().item_substs.get(&id) {
2109 None => ItemSubsts {
2110 substs: Substs::empty(self.global_tcx())
2112 Some(ts) => ts.clone(),
2116 // Returns the type of a pattern as a monotype. Like @expr_ty, this function
2117 // doesn't provide type parameter substitutions.
2118 pub fn pat_ty(self, pat: &hir::Pat) -> Ty<'gcx> {
2119 self.node_id_to_type(pat.id)
2121 pub fn pat_ty_opt(self, pat: &hir::Pat) -> Option<Ty<'gcx>> {
2122 self.node_id_to_type_opt(pat.id)
2125 // Returns the type of an expression as a monotype.
2127 // NB (1): This is the PRE-ADJUSTMENT TYPE for the expression. That is, in
2128 // some cases, we insert `AutoAdjustment` annotations such as auto-deref or
2129 // auto-ref. The type returned by this function does not consider such
2130 // adjustments. See `expr_ty_adjusted()` instead.
2132 // NB (2): This type doesn't provide type parameter substitutions; e.g. if you
2133 // ask for the type of "id" in "id(3)", it will return "fn(&isize) -> isize"
2134 // instead of "fn(ty) -> T with T = isize".
2135 pub fn expr_ty(self, expr: &hir::Expr) -> Ty<'gcx> {
2136 self.node_id_to_type(expr.id)
2139 pub fn expr_ty_opt(self, expr: &hir::Expr) -> Option<Ty<'gcx>> {
2140 self.node_id_to_type_opt(expr.id)
2143 /// Returns the type of `expr`, considering any `AutoAdjustment`
2144 /// entry recorded for that expression.
2146 /// It would almost certainly be better to store the adjusted ty in with
2147 /// the `AutoAdjustment`, but I opted not to do this because it would
2148 /// require serializing and deserializing the type and, although that's not
2149 /// hard to do, I just hate that code so much I didn't want to touch it
2150 /// unless it was to fix it properly, which seemed a distraction from the
2151 /// thread at hand! -nmatsakis
2152 pub fn expr_ty_adjusted(self, expr: &hir::Expr) -> Ty<'gcx> {
2154 .adjust(self.global_tcx(), expr.span, expr.id,
2155 self.tables.borrow().adjustments.get(&expr.id),
2157 self.tables.borrow().method_map.get(&method_call).map(|method| method.ty)
2161 pub fn expr_ty_adjusted_opt(self, expr: &hir::Expr) -> Option<Ty<'gcx>> {
2162 self.expr_ty_opt(expr).map(|t| t.adjust(self.global_tcx(),
2165 self.tables.borrow().adjustments.get(&expr.id),
2167 self.tables.borrow().method_map.get(&method_call).map(|method| method.ty)
2171 pub fn expr_span(self, id: NodeId) -> Span {
2172 match self.map.find(id) {
2173 Some(ast_map::NodeExpr(e)) => {
2177 bug!("Node id {} is not an expr: {:?}", id, f);
2180 bug!("Node id {} is not present in the node map", id);
2185 pub fn local_var_name_str(self, id: NodeId) -> InternedString {
2186 match self.map.find(id) {
2187 Some(ast_map::NodeLocal(pat)) => {
2189 hir::PatKind::Binding(_, ref path1, _) => path1.node.as_str(),
2191 bug!("Variable id {} maps to {:?}, not local", id, pat);
2195 r => bug!("Variable id {} maps to {:?}, not local", id, r),
2199 pub fn expr_is_lval(self, expr: &hir::Expr) -> bool {
2201 hir::ExprPath(..) => {
2202 // This function can be used during type checking when not all paths are
2203 // fully resolved. Partially resolved paths in expressions can only legally
2204 // refer to associated items which are always rvalues.
2205 match self.expect_resolution(expr.id).base_def {
2206 Def::Local(..) | Def::Upvar(..) | Def::Static(..) | Def::Err => true,
2211 hir::ExprType(ref e, _) => {
2212 self.expr_is_lval(e)
2215 hir::ExprUnary(hir::UnDeref, _) |
2216 hir::ExprField(..) |
2217 hir::ExprTupField(..) |
2218 hir::ExprIndex(..) => {
2223 hir::ExprMethodCall(..) |
2224 hir::ExprStruct(..) |
2227 hir::ExprMatch(..) |
2228 hir::ExprClosure(..) |
2229 hir::ExprBlock(..) |
2230 hir::ExprRepeat(..) |
2231 hir::ExprArray(..) |
2232 hir::ExprBreak(..) |
2233 hir::ExprAgain(..) |
2235 hir::ExprWhile(..) |
2237 hir::ExprAssign(..) |
2238 hir::ExprInlineAsm(..) |
2239 hir::ExprAssignOp(..) |
2241 hir::ExprUnary(..) |
2243 hir::ExprAddrOf(..) |
2244 hir::ExprBinary(..) |
2245 hir::ExprCast(..) => {
2251 pub fn provided_trait_methods(self, id: DefId) -> Vec<Rc<Method<'gcx>>> {
2252 self.impl_or_trait_items(id).iter().filter_map(|&def_id| {
2253 match self.impl_or_trait_item(def_id) {
2254 MethodTraitItem(ref m) if m.has_body => Some(m.clone()),
2260 pub fn trait_impl_polarity(self, id: DefId) -> hir::ImplPolarity {
2261 if let Some(id) = self.map.as_local_node_id(id) {
2262 match self.map.expect_item(id).node {
2263 hir::ItemImpl(_, polarity, ..) => polarity,
2264 ref item => bug!("trait_impl_polarity: {:?} not an impl", item)
2267 self.sess.cstore.impl_polarity(id)
2271 pub fn custom_coerce_unsized_kind(self, did: DefId) -> adjustment::CustomCoerceUnsized {
2272 self.custom_coerce_unsized_kinds.memoize(did, || {
2273 let (kind, src) = if did.krate != LOCAL_CRATE {
2274 (self.sess.cstore.custom_coerce_unsized_kind(did), "external")
2282 bug!("custom_coerce_unsized_kind: \
2283 {} impl `{}` is missing its kind",
2284 src, self.item_path_str(did));
2290 pub fn impl_or_trait_item(self, id: DefId) -> ImplOrTraitItem<'gcx> {
2291 lookup_locally_or_in_crate_store(
2292 "impl_or_trait_items", id, &self.impl_or_trait_items,
2293 || self.sess.cstore.impl_or_trait_item(self.global_tcx(), id)
2294 .expect("missing ImplOrTraitItem in metadata"))
2297 pub fn impl_or_trait_items(self, id: DefId) -> Rc<Vec<DefId>> {
2298 lookup_locally_or_in_crate_store(
2299 "impl_or_trait_items", id, &self.impl_or_trait_item_def_ids,
2300 || Rc::new(self.sess.cstore.impl_or_trait_items(id)))
2303 /// Returns the trait-ref corresponding to a given impl, or None if it is
2304 /// an inherent impl.
2305 pub fn impl_trait_ref(self, id: DefId) -> Option<TraitRef<'gcx>> {
2306 lookup_locally_or_in_crate_store(
2307 "impl_trait_refs", id, &self.impl_trait_refs,
2308 || self.sess.cstore.impl_trait_ref(self.global_tcx(), id))
2311 /// Returns a path resolution for node id if it exists, panics otherwise.
2312 pub fn expect_resolution(self, id: NodeId) -> PathResolution {
2313 *self.def_map.borrow().get(&id).expect("no def-map entry for node id")
2316 /// Returns a fully resolved definition for node id if it exists, panics otherwise.
2317 pub fn expect_def(self, id: NodeId) -> Def {
2318 self.expect_resolution(id).full_def()
2321 /// Returns a fully resolved definition for node id if it exists, or none if no
2322 /// definition exists, panics on partial resolutions to catch errors.
2323 pub fn expect_def_or_none(self, id: NodeId) -> Option<Def> {
2324 self.def_map.borrow().get(&id).map(|resolution| resolution.full_def())
2327 // Returns `ty::VariantDef` if `def` refers to a struct,
2328 // or variant or their constructors, panics otherwise.
2329 pub fn expect_variant_def(self, def: Def) -> VariantDef<'tcx> {
2331 Def::Variant(did) => {
2332 let enum_did = self.parent_def_id(did).unwrap();
2333 self.lookup_adt_def(enum_did).variant_with_id(did)
2335 Def::Struct(did) | Def::Union(did) => {
2336 self.lookup_adt_def(did).struct_variant()
2338 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2342 pub fn def_key(self, id: DefId) -> ast_map::DefKey {
2344 self.map.def_key(id)
2346 self.sess.cstore.def_key(id)
2350 /// Convert a `DefId` into its fully expanded `DefPath` (every
2351 /// `DefId` is really just an interned def-path).
2353 /// Note that if `id` is not local to this crate -- or is
2354 /// inlined into this crate -- the result will be a non-local
2357 /// This function is only safe to use when you are sure that the
2358 /// full def-path is accessible. Examples that are known to be
2359 /// safe are local def-ids or items; see `opt_def_path` for more
2361 pub fn def_path(self, id: DefId) -> ast_map::DefPath {
2362 self.opt_def_path(id).unwrap_or_else(|| {
2363 bug!("could not load def-path for {:?}", id)
2367 /// Convert a `DefId` into its fully expanded `DefPath` (every
2368 /// `DefId` is really just an interned def-path).
2370 /// When going across crates, we do not save the full info for
2371 /// every cross-crate def-id, and hence we may not always be able
2372 /// to create a def-path. Therefore, this returns
2373 /// `Option<DefPath>` to cover that possibility. It will always
2374 /// return `Some` for local def-ids, however, as well as for
2375 /// items. The problems arise with "minor" def-ids like those
2376 /// associated with a pattern, `impl Trait`, or other internal
2379 /// Note that if `id` is not local to this crate -- or is
2380 /// inlined into this crate -- the result will be a non-local
2382 pub fn opt_def_path(self, id: DefId) -> Option<ast_map::DefPath> {
2384 Some(self.map.def_path(id))
2386 self.sess.cstore.relative_def_path(id)
2390 pub fn item_name(self, id: DefId) -> ast::Name {
2391 if let Some(id) = self.map.as_local_node_id(id) {
2393 } else if id.index == CRATE_DEF_INDEX {
2394 token::intern(&self.sess.cstore.original_crate_name(id.krate))
2396 let def_key = self.sess.cstore.def_key(id);
2397 // The name of a StructCtor is that of its struct parent.
2398 if let ast_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2399 self.item_name(DefId {
2401 index: def_key.parent.unwrap()
2404 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2405 bug!("item_name: no name for {:?}", self.def_path(id));
2411 // Register a given item type
2412 pub fn register_item_type(self, did: DefId, scheme: TypeScheme<'gcx>) {
2413 self.tcache.borrow_mut().insert(did, scheme.ty);
2414 self.generics.borrow_mut().insert(did, scheme.generics);
2417 // If the given item is in an external crate, looks up its type and adds it to
2418 // the type cache. Returns the type parameters and type.
2419 pub fn lookup_item_type(self, did: DefId) -> TypeScheme<'gcx> {
2420 let ty = lookup_locally_or_in_crate_store(
2421 "tcache", did, &self.tcache,
2422 || self.sess.cstore.item_type(self.global_tcx(), did));
2426 generics: self.lookup_generics(did)
2430 pub fn opt_lookup_item_type(self, did: DefId) -> Option<TypeScheme<'gcx>> {
2431 if did.krate != LOCAL_CRATE {
2432 return Some(self.lookup_item_type(did));
2435 if let Some(ty) = self.tcache.borrow().get(&did).cloned() {
2438 generics: self.lookup_generics(did)
2445 /// Given the did of a trait, returns its canonical trait ref.
2446 pub fn lookup_trait_def(self, did: DefId) -> &'gcx TraitDef<'gcx> {
2447 lookup_locally_or_in_crate_store(
2448 "trait_defs", did, &self.trait_defs,
2449 || self.alloc_trait_def(self.sess.cstore.trait_def(self.global_tcx(), did))
2453 /// Given the did of an ADT, return a master reference to its
2454 /// definition. Unless you are planning on fulfilling the ADT's fields,
2455 /// use lookup_adt_def instead.
2456 pub fn lookup_adt_def_master(self, did: DefId) -> AdtDefMaster<'gcx> {
2457 lookup_locally_or_in_crate_store(
2458 "adt_defs", did, &self.adt_defs,
2459 || self.sess.cstore.adt_def(self.global_tcx(), did)
2463 /// Given the did of an ADT, return a reference to its definition.
2464 pub fn lookup_adt_def(self, did: DefId) -> AdtDef<'gcx> {
2465 // when reverse-variance goes away, a transmute::<AdtDefMaster,AdtDef>
2466 // would be needed here.
2467 self.lookup_adt_def_master(did)
2470 /// Given the did of an item, returns its generics.
2471 pub fn lookup_generics(self, did: DefId) -> &'gcx Generics<'gcx> {
2472 lookup_locally_or_in_crate_store(
2473 "generics", did, &self.generics,
2474 || self.alloc_generics(self.sess.cstore.item_generics(self.global_tcx(), did)))
2477 /// Given the did of an item, returns its full set of predicates.
2478 pub fn lookup_predicates(self, did: DefId) -> GenericPredicates<'gcx> {
2479 lookup_locally_or_in_crate_store(
2480 "predicates", did, &self.predicates,
2481 || self.sess.cstore.item_predicates(self.global_tcx(), did))
2484 /// Given the did of a trait, returns its superpredicates.
2485 pub fn lookup_super_predicates(self, did: DefId) -> GenericPredicates<'gcx> {
2486 lookup_locally_or_in_crate_store(
2487 "super_predicates", did, &self.super_predicates,
2488 || self.sess.cstore.item_super_predicates(self.global_tcx(), did))
2491 /// If `type_needs_drop` returns true, then `ty` is definitely
2492 /// non-copy and *might* have a destructor attached; if it returns
2493 /// false, then `ty` definitely has no destructor (i.e. no drop glue).
2495 /// (Note that this implies that if `ty` has a destructor attached,
2496 /// then `type_needs_drop` will definitely return `true` for `ty`.)
2497 pub fn type_needs_drop_given_env(self,
2499 param_env: &ty::ParameterEnvironment<'gcx>) -> bool {
2500 // Issue #22536: We first query type_moves_by_default. It sees a
2501 // normalized version of the type, and therefore will definitely
2502 // know whether the type implements Copy (and thus needs no
2503 // cleanup/drop/zeroing) ...
2504 let tcx = self.global_tcx();
2505 let implements_copy = !ty.moves_by_default(tcx, param_env, DUMMY_SP);
2507 if implements_copy { return false; }
2509 // ... (issue #22536 continued) but as an optimization, still use
2510 // prior logic of asking if the `needs_drop` bit is set; we need
2511 // not zero non-Copy types if they have no destructor.
2513 // FIXME(#22815): Note that calling `ty::type_contents` is a
2514 // conservative heuristic; it may report that `needs_drop` is set
2515 // when actual type does not actually have a destructor associated
2516 // with it. But since `ty` absolutely did not have the `Copy`
2517 // bound attached (see above), it is sound to treat it as having a
2518 // destructor (e.g. zero its memory on move).
2520 let contents = ty.type_contents(tcx);
2521 debug!("type_needs_drop ty={:?} contents={:?}", ty, contents);
2522 contents.needs_drop(tcx)
2525 /// Get the attributes of a definition.
2526 pub fn get_attrs(self, did: DefId) -> Cow<'gcx, [ast::Attribute]> {
2527 if let Some(id) = self.map.as_local_node_id(did) {
2528 Cow::Borrowed(self.map.attrs(id))
2530 Cow::Owned(self.sess.cstore.item_attrs(did))
2534 /// Determine whether an item is annotated with an attribute
2535 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2536 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2539 /// Determine whether an item is annotated with `#[repr(packed)]`
2540 pub fn lookup_packed(self, did: DefId) -> bool {
2541 self.lookup_repr_hints(did).contains(&attr::ReprPacked)
2544 /// Determine whether an item is annotated with `#[simd]`
2545 pub fn lookup_simd(self, did: DefId) -> bool {
2546 self.has_attr(did, "simd")
2547 || self.lookup_repr_hints(did).contains(&attr::ReprSimd)
2550 pub fn item_variances(self, item_id: DefId) -> Rc<Vec<ty::Variance>> {
2551 lookup_locally_or_in_crate_store(
2552 "item_variance_map", item_id, &self.item_variance_map,
2553 || Rc::new(self.sess.cstore.item_variances(item_id)))
2556 pub fn trait_has_default_impl(self, trait_def_id: DefId) -> bool {
2557 self.populate_implementations_for_trait_if_necessary(trait_def_id);
2559 let def = self.lookup_trait_def(trait_def_id);
2560 def.flags.get().intersects(TraitFlags::HAS_DEFAULT_IMPL)
2563 /// Records a trait-to-implementation mapping.
2564 pub fn record_trait_has_default_impl(self, trait_def_id: DefId) {
2565 let def = self.lookup_trait_def(trait_def_id);
2566 def.flags.set(def.flags.get() | TraitFlags::HAS_DEFAULT_IMPL)
2569 /// Load primitive inherent implementations if necessary
2570 pub fn populate_implementations_for_primitive_if_necessary(self,
2571 primitive_def_id: DefId) {
2572 if primitive_def_id.is_local() {
2576 // The primitive is not local, hence we are reading this out
2578 let _ignore = self.dep_graph.in_ignore();
2580 if self.populated_external_primitive_impls.borrow().contains(&primitive_def_id) {
2584 debug!("populate_implementations_for_primitive_if_necessary: searching for {:?}",
2587 let impl_items = self.sess.cstore.impl_or_trait_items(primitive_def_id);
2589 // Store the implementation info.
2590 self.impl_or_trait_item_def_ids.borrow_mut().insert(primitive_def_id, Rc::new(impl_items));
2591 self.populated_external_primitive_impls.borrow_mut().insert(primitive_def_id);
2594 /// Populates the type context with all the inherent implementations for
2595 /// the given type if necessary.
2596 pub fn populate_inherent_implementations_for_type_if_necessary(self,
2598 if type_id.is_local() {
2602 // The type is not local, hence we are reading this out of
2603 // metadata and don't need to track edges.
2604 let _ignore = self.dep_graph.in_ignore();
2606 if self.populated_external_types.borrow().contains(&type_id) {
2610 debug!("populate_inherent_implementations_for_type_if_necessary: searching for {:?}",
2613 let inherent_impls = self.sess.cstore.inherent_implementations_for_type(type_id);
2614 for &impl_def_id in &inherent_impls {
2615 // Store the implementation info.
2616 let impl_items = self.sess.cstore.impl_or_trait_items(impl_def_id);
2617 self.impl_or_trait_item_def_ids.borrow_mut().insert(impl_def_id, Rc::new(impl_items));
2620 self.inherent_impls.borrow_mut().insert(type_id, inherent_impls);
2621 self.populated_external_types.borrow_mut().insert(type_id);
2624 /// Populates the type context with all the implementations for the given
2625 /// trait if necessary.
2626 pub fn populate_implementations_for_trait_if_necessary(self, trait_id: DefId) {
2627 if trait_id.is_local() {
2631 // The type is not local, hence we are reading this out of
2632 // metadata and don't need to track edges.
2633 let _ignore = self.dep_graph.in_ignore();
2635 let def = self.lookup_trait_def(trait_id);
2636 if def.flags.get().intersects(TraitFlags::IMPLS_VALID) {
2640 debug!("populate_implementations_for_trait_if_necessary: searching for {:?}", def);
2642 if self.sess.cstore.is_defaulted_trait(trait_id) {
2643 self.record_trait_has_default_impl(trait_id);
2646 for impl_def_id in self.sess.cstore.implementations_of_trait(Some(trait_id)) {
2647 let impl_items = self.sess.cstore.impl_or_trait_items(impl_def_id);
2648 let trait_ref = self.impl_trait_ref(impl_def_id).unwrap();
2650 // Record the trait->implementation mapping.
2651 let parent = self.sess.cstore.impl_parent(impl_def_id).unwrap_or(trait_id);
2652 def.record_remote_impl(self, impl_def_id, trait_ref, parent);
2654 // For any methods that use a default implementation, add them to
2655 // the map. This is a bit unfortunate.
2656 for &impl_item_def_id in &impl_items {
2657 // load impl items eagerly for convenience
2658 // FIXME: we may want to load these lazily
2659 self.impl_or_trait_item(impl_item_def_id);
2662 // Store the implementation info.
2663 self.impl_or_trait_item_def_ids.borrow_mut().insert(impl_def_id, Rc::new(impl_items));
2666 def.flags.set(def.flags.get() | TraitFlags::IMPLS_VALID);
2669 pub fn closure_kind(self, def_id: DefId) -> ty::ClosureKind {
2670 // If this is a local def-id, it should be inserted into the
2671 // tables by typeck; else, it will be retreived from
2672 // the external crate metadata.
2673 if let Some(&kind) = self.tables.borrow().closure_kinds.get(&def_id) {
2677 let kind = self.sess.cstore.closure_kind(def_id);
2678 self.tables.borrow_mut().closure_kinds.insert(def_id, kind);
2682 pub fn closure_type(self,
2684 substs: ClosureSubsts<'tcx>)
2685 -> ty::ClosureTy<'tcx>
2687 // If this is a local def-id, it should be inserted into the
2688 // tables by typeck; else, it will be retreived from
2689 // the external crate metadata.
2690 if let Some(ty) = self.tables.borrow().closure_tys.get(&def_id) {
2691 return ty.subst(self, substs.func_substs);
2694 let ty = self.sess.cstore.closure_ty(self.global_tcx(), def_id);
2695 self.tables.borrow_mut().closure_tys.insert(def_id, ty.clone());
2696 ty.subst(self, substs.func_substs)
2699 /// Given the def_id of an impl, return the def_id of the trait it implements.
2700 /// If it implements no trait, return `None`.
2701 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2702 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2705 /// If the given def ID describes a method belonging to an impl, return the
2706 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2707 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2708 if def_id.krate != LOCAL_CRATE {
2709 return self.sess.cstore.impl_or_trait_item(self.global_tcx(), def_id)
2711 match item.container() {
2712 TraitContainer(_) => None,
2713 ImplContainer(def_id) => Some(def_id),
2717 match self.impl_or_trait_items.borrow().get(&def_id).cloned() {
2718 Some(trait_item) => {
2719 match trait_item.container() {
2720 TraitContainer(_) => None,
2721 ImplContainer(def_id) => Some(def_id),
2728 /// If the given def ID describes an item belonging to a trait,
2729 /// return the ID of the trait that the trait item belongs to.
2730 /// Otherwise, return `None`.
2731 pub fn trait_of_item(self, def_id: DefId) -> Option<DefId> {
2732 if def_id.krate != LOCAL_CRATE {
2733 return self.sess.cstore.trait_of_item(def_id);
2735 match self.impl_or_trait_items.borrow().get(&def_id) {
2736 Some(impl_or_trait_item) => {
2737 match impl_or_trait_item.container() {
2738 TraitContainer(def_id) => Some(def_id),
2739 ImplContainer(_) => None
2746 /// If the given def ID describes an item belonging to a trait, (either a
2747 /// default method or an implementation of a trait method), return the ID of
2748 /// the method inside trait definition (this means that if the given def ID
2749 /// is already that of the original trait method, then the return value is
2751 /// Otherwise, return `None`.
2752 pub fn trait_item_of_item(self, def_id: DefId) -> Option<DefId> {
2753 let impl_or_trait_item = match self.impl_or_trait_items.borrow().get(&def_id) {
2754 Some(m) => m.clone(),
2755 None => return None,
2757 match impl_or_trait_item.container() {
2758 TraitContainer(_) => Some(impl_or_trait_item.def_id()),
2759 ImplContainer(def_id) => {
2760 self.trait_id_of_impl(def_id).and_then(|trait_did| {
2761 let name = impl_or_trait_item.name();
2762 self.trait_items(trait_did).iter()
2763 .find(|item| item.name() == name)
2764 .map(|item| item.def_id())
2770 /// Construct a parameter environment suitable for static contexts or other contexts where there
2771 /// are no free type/lifetime parameters in scope.
2772 pub fn empty_parameter_environment(self) -> ParameterEnvironment<'tcx> {
2774 // for an empty parameter environment, there ARE no free
2775 // regions, so it shouldn't matter what we use for the free id
2776 let free_id_outlive = self.region_maps.node_extent(ast::DUMMY_NODE_ID);
2777 ty::ParameterEnvironment {
2778 free_substs: Substs::empty(self),
2779 caller_bounds: Vec::new(),
2780 implicit_region_bound: self.mk_region(ty::ReEmpty),
2781 free_id_outlive: free_id_outlive
2785 /// Constructs and returns a substitution that can be applied to move from
2786 /// the "outer" view of a type or method to the "inner" view.
2787 /// In general, this means converting from bound parameters to
2788 /// free parameters. Since we currently represent bound/free type
2789 /// parameters in the same way, this only has an effect on regions.
2790 pub fn construct_free_substs(self, def_id: DefId,
2791 free_id_outlive: CodeExtent)
2792 -> &'gcx Substs<'gcx> {
2794 let substs = Substs::for_item(self.global_tcx(), def_id, |def, _| {
2795 // map bound 'a => free 'a
2796 self.global_tcx().mk_region(ReFree(FreeRegion {
2797 scope: free_id_outlive,
2798 bound_region: def.to_bound_region()
2802 self.global_tcx().mk_param_from_def(def)
2805 debug!("construct_parameter_environment: {:?}", substs);
2809 /// See `ParameterEnvironment` struct def'n for details.
2810 /// If you were using `free_id: NodeId`, you might try `self.region_maps.item_extent(free_id)`
2811 /// for the `free_id_outlive` parameter. (But note that this is not always quite right.)
2812 pub fn construct_parameter_environment(self,
2815 free_id_outlive: CodeExtent)
2816 -> ParameterEnvironment<'gcx>
2819 // Construct the free substs.
2822 let free_substs = self.construct_free_substs(def_id, free_id_outlive);
2825 // Compute the bounds on Self and the type parameters.
2828 let tcx = self.global_tcx();
2829 let generic_predicates = tcx.lookup_predicates(def_id);
2830 let bounds = generic_predicates.instantiate(tcx, free_substs);
2831 let bounds = tcx.liberate_late_bound_regions(free_id_outlive, &ty::Binder(bounds));
2832 let predicates = bounds.predicates;
2834 // Finally, we have to normalize the bounds in the environment, in
2835 // case they contain any associated type projections. This process
2836 // can yield errors if the put in illegal associated types, like
2837 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2838 // report these errors right here; this doesn't actually feel
2839 // right to me, because constructing the environment feels like a
2840 // kind of a "idempotent" action, but I'm not sure where would be
2841 // a better place. In practice, we construct environments for
2842 // every fn once during type checking, and we'll abort if there
2843 // are any errors at that point, so after type checking you can be
2844 // sure that this will succeed without errors anyway.
2847 let unnormalized_env = ty::ParameterEnvironment {
2848 free_substs: free_substs,
2849 implicit_region_bound: tcx.mk_region(ty::ReScope(free_id_outlive)),
2850 caller_bounds: predicates,
2851 free_id_outlive: free_id_outlive,
2854 let cause = traits::ObligationCause::misc(span, free_id_outlive.node_id(&self.region_maps));
2855 traits::normalize_param_env_or_error(tcx, unnormalized_env, cause)
2858 pub fn node_scope_region(self, id: NodeId) -> &'tcx Region {
2859 self.mk_region(ty::ReScope(self.region_maps.node_extent(id)))
2862 pub fn is_method_call(self, expr_id: NodeId) -> bool {
2863 self.tables.borrow().method_map.contains_key(&MethodCall::expr(expr_id))
2866 pub fn is_overloaded_autoderef(self, expr_id: NodeId, autoderefs: u32) -> bool {
2867 self.tables.borrow().method_map.contains_key(&MethodCall::autoderef(expr_id,
2871 pub fn upvar_capture(self, upvar_id: ty::UpvarId) -> Option<ty::UpvarCapture<'tcx>> {
2872 Some(self.tables.borrow().upvar_capture_map.get(&upvar_id).unwrap().clone())
2875 pub fn visit_all_items_in_krate<V,F>(self,
2878 where F: FnMut(DefId) -> DepNode<DefId>, V: Visitor<'gcx>
2880 dep_graph::visit_all_items_in_krate(self.global_tcx(), dep_node_fn, visitor);
2883 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2884 /// with the name of the crate containing the impl.
2885 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, InternedString> {
2886 if impl_did.is_local() {
2887 let node_id = self.map.as_local_node_id(impl_did).unwrap();
2888 Ok(self.map.span(node_id))
2890 Err(self.sess.cstore.crate_name(impl_did.krate))
2895 /// The category of explicit self.
2896 #[derive(Clone, Copy, Eq, PartialEq, Debug, RustcEncodable, RustcDecodable)]
2897 pub enum ExplicitSelfCategory<'tcx> {
2900 ByReference(&'tcx Region, hir::Mutability),
2904 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2905 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2906 F: FnOnce(&[hir::Freevar]) -> T,
2908 match self.freevars.borrow().get(&fid) {
2910 Some(d) => f(&d[..])