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::AssociatedItemContainer::*;
13 pub use self::BorrowKind::*;
14 pub use self::IntVarValue::*;
15 pub use self::LvaluePreference::*;
16 pub use self::fold::TypeFoldable;
18 use dep_graph::{self, DepNode};
19 use hir::{map as hir_map, FreevarMap, TraitMap};
20 use hir::def::{Def, CtorKind, ExportMap};
21 use hir::def_id::{CrateNum, DefId, DefIndex, CRATE_DEF_INDEX, LOCAL_CRATE};
22 use ich::StableHashingContext;
23 use middle::const_val::ConstVal;
24 use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
25 use middle::privacy::AccessLevels;
26 use middle::region::{CodeExtent, ROOT_CODE_EXTENT};
27 use middle::resolve_lifetime::ObjectLifetimeDefault;
31 use ty::subst::{Subst, Substs};
32 use ty::util::IntTypeExt;
33 use ty::walk::TypeWalker;
34 use util::nodemap::{NodeSet, DefIdMap, FxHashMap};
36 use serialize::{self, Encodable, Encoder};
38 use std::cell::{Cell, RefCell, Ref};
39 use std::collections::BTreeMap;
40 use std::hash::{Hash, Hasher};
44 use std::vec::IntoIter;
46 use syntax::ast::{self, Name, NodeId};
48 use syntax::symbol::{Symbol, InternedString};
49 use syntax_pos::{DUMMY_SP, Span};
50 use rustc_const_math::ConstInt;
52 use rustc_data_structures::accumulate_vec::IntoIter as AccIntoIter;
53 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
57 use hir::itemlikevisit::ItemLikeVisitor;
59 pub use self::sty::{Binder, DebruijnIndex};
60 pub use self::sty::{FnSig, PolyFnSig};
61 pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
62 pub use self::sty::{ClosureSubsts, TypeAndMut};
63 pub use self::sty::{TraitRef, TypeVariants, PolyTraitRef};
64 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
65 pub use self::sty::{ExistentialProjection, PolyExistentialProjection};
66 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
67 pub use self::sty::Issue32330;
68 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid, SkolemizedRegionVid};
69 pub use self::sty::BoundRegion::*;
70 pub use self::sty::InferTy::*;
71 pub use self::sty::Region::*;
72 pub use self::sty::TypeVariants::*;
74 pub use self::context::{TyCtxt, GlobalArenas, tls};
75 pub use self::context::{Lift, TypeckTables};
77 pub use self::instance::{Instance, InstanceDef};
79 pub use self::trait_def::{TraitDef, TraitFlags};
81 pub use self::maps::queries;
88 pub mod inhabitedness;
104 mod structural_impls;
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 /// NB: These contents are being migrated into queries using the
113 /// *on-demand* infrastructure.
115 pub struct CrateAnalysis {
116 pub access_levels: Rc<AccessLevels>,
117 pub reachable: NodeSet,
119 pub glob_map: Option<hir::GlobMap>,
123 pub struct Resolutions {
124 pub freevars: FreevarMap,
125 pub trait_map: TraitMap,
126 pub maybe_unused_trait_imports: NodeSet,
127 pub export_map: ExportMap,
130 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
131 pub enum AssociatedItemContainer {
132 TraitContainer(DefId),
133 ImplContainer(DefId),
136 impl AssociatedItemContainer {
137 pub fn id(&self) -> DefId {
139 TraitContainer(id) => id,
140 ImplContainer(id) => id,
145 /// The "header" of an impl is everything outside the body: a Self type, a trait
146 /// ref (in the case of a trait impl), and a set of predicates (from the
147 /// bounds/where clauses).
148 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
149 pub struct ImplHeader<'tcx> {
150 pub impl_def_id: DefId,
151 pub self_ty: Ty<'tcx>,
152 pub trait_ref: Option<TraitRef<'tcx>>,
153 pub predicates: Vec<Predicate<'tcx>>,
156 impl<'a, 'gcx, 'tcx> ImplHeader<'tcx> {
157 pub fn with_fresh_ty_vars(selcx: &mut traits::SelectionContext<'a, 'gcx, 'tcx>,
161 let tcx = selcx.tcx();
162 let impl_substs = selcx.infcx().fresh_substs_for_item(DUMMY_SP, impl_def_id);
164 let header = ImplHeader {
165 impl_def_id: impl_def_id,
166 self_ty: tcx.item_type(impl_def_id),
167 trait_ref: tcx.impl_trait_ref(impl_def_id),
168 predicates: tcx.item_predicates(impl_def_id).predicates
169 }.subst(tcx, impl_substs);
171 let traits::Normalized { value: mut header, obligations } =
172 traits::normalize(selcx, traits::ObligationCause::dummy(), &header);
174 header.predicates.extend(obligations.into_iter().map(|o| o.predicate));
179 #[derive(Copy, Clone, Debug)]
180 pub struct AssociatedItem {
183 pub kind: AssociatedKind,
185 pub defaultness: hir::Defaultness,
186 pub container: AssociatedItemContainer,
188 /// Whether this is a method with an explicit self
189 /// as its first argument, allowing method calls.
190 pub method_has_self_argument: bool,
193 #[derive(Copy, Clone, PartialEq, Eq, Debug, RustcEncodable, RustcDecodable)]
194 pub enum AssociatedKind {
200 impl AssociatedItem {
201 pub fn def(&self) -> Def {
203 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
204 AssociatedKind::Method => Def::Method(self.def_id),
205 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
209 /// Tests whether the associated item admits a non-trivial implementation
211 pub fn relevant_for_never<'tcx>(&self) -> bool {
213 AssociatedKind::Const => true,
214 AssociatedKind::Type => true,
215 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
216 AssociatedKind::Method => !self.method_has_self_argument,
221 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
222 pub enum Visibility {
223 /// Visible everywhere (including in other crates).
225 /// Visible only in the given crate-local module.
227 /// Not visible anywhere in the local crate. This is the visibility of private external items.
231 pub trait DefIdTree: Copy {
232 fn parent(self, id: DefId) -> Option<DefId>;
234 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
235 if descendant.krate != ancestor.krate {
239 while descendant != ancestor {
240 match self.parent(descendant) {
241 Some(parent) => descendant = parent,
242 None => return false,
249 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
250 fn parent(self, id: DefId) -> Option<DefId> {
251 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
256 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt) -> Self {
258 hir::Public => Visibility::Public,
259 hir::Visibility::Crate => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
260 hir::Visibility::Restricted { ref path, .. } => match path.def {
261 // If there is no resolution, `resolve` will have already reported an error, so
262 // assume that the visibility is public to avoid reporting more privacy errors.
263 Def::Err => Visibility::Public,
264 def => Visibility::Restricted(def.def_id()),
267 Visibility::Restricted(tcx.hir.local_def_id(tcx.hir.get_module_parent(id)))
272 /// Returns true if an item with this visibility is accessible from the given block.
273 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
274 let restriction = match self {
275 // Public items are visible everywhere.
276 Visibility::Public => return true,
277 // Private items from other crates are visible nowhere.
278 Visibility::Invisible => return false,
279 // Restricted items are visible in an arbitrary local module.
280 Visibility::Restricted(other) if other.krate != module.krate => return false,
281 Visibility::Restricted(module) => module,
284 tree.is_descendant_of(module, restriction)
287 /// Returns true if this visibility is at least as accessible as the given visibility
288 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
289 let vis_restriction = match vis {
290 Visibility::Public => return self == Visibility::Public,
291 Visibility::Invisible => return true,
292 Visibility::Restricted(module) => module,
295 self.is_accessible_from(vis_restriction, tree)
299 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
301 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
302 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
303 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
304 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
307 #[derive(Clone, Copy, Debug, RustcDecodable, RustcEncodable)]
308 pub struct MethodCallee<'tcx> {
309 /// Impl method ID, for inherent methods, or trait method ID, otherwise.
312 pub substs: &'tcx Substs<'tcx>
315 /// With method calls, we store some extra information in
316 /// side tables (i.e method_map). We use
317 /// MethodCall as a key to index into these tables instead of
318 /// just directly using the expression's NodeId. The reason
319 /// for this being that we may apply adjustments (coercions)
320 /// with the resulting expression also needing to use the
321 /// side tables. The problem with this is that we don't
322 /// assign a separate NodeId to this new expression
323 /// and so it would clash with the base expression if both
324 /// needed to add to the side tables. Thus to disambiguate
325 /// we also keep track of whether there's an adjustment in
327 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
328 pub struct MethodCall {
334 pub fn expr(id: NodeId) -> MethodCall {
341 pub fn autoderef(expr_id: NodeId, autoderef: u32) -> MethodCall {
344 autoderef: 1 + autoderef
349 // maps from an expression id that corresponds to a method call to the details
350 // of the method to be invoked
351 pub type MethodMap<'tcx> = FxHashMap<MethodCall, MethodCallee<'tcx>>;
353 // Contains information needed to resolve types and (in the future) look up
354 // the types of AST nodes.
355 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
356 pub struct CReaderCacheKey {
361 /// Describes the fragment-state associated with a NodeId.
363 /// Currently only unfragmented paths have entries in the table,
364 /// but longer-term this enum is expected to expand to also
365 /// include data for fragmented paths.
366 #[derive(Copy, Clone, Debug)]
367 pub enum FragmentInfo {
368 Moved { var: NodeId, move_expr: NodeId },
369 Assigned { var: NodeId, assign_expr: NodeId, assignee_id: NodeId },
372 // Flags that we track on types. These flags are propagated upwards
373 // through the type during type construction, so that we can quickly
374 // check whether the type has various kinds of types in it without
375 // recursing over the type itself.
377 flags TypeFlags: u32 {
378 const HAS_PARAMS = 1 << 0,
379 const HAS_SELF = 1 << 1,
380 const HAS_TY_INFER = 1 << 2,
381 const HAS_RE_INFER = 1 << 3,
382 const HAS_RE_SKOL = 1 << 4,
383 const HAS_RE_EARLY_BOUND = 1 << 5,
384 const HAS_FREE_REGIONS = 1 << 6,
385 const HAS_TY_ERR = 1 << 7,
386 const HAS_PROJECTION = 1 << 8,
387 const HAS_TY_CLOSURE = 1 << 9,
389 // true if there are "names" of types and regions and so forth
390 // that are local to a particular fn
391 const HAS_LOCAL_NAMES = 1 << 10,
393 // Present if the type belongs in a local type context.
394 // Only set for TyInfer other than Fresh.
395 const KEEP_IN_LOCAL_TCX = 1 << 11,
397 // Is there a projection that does not involve a bound region?
398 // Currently we can't normalize projections w/ bound regions.
399 const HAS_NORMALIZABLE_PROJECTION = 1 << 12,
401 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
402 TypeFlags::HAS_SELF.bits |
403 TypeFlags::HAS_RE_EARLY_BOUND.bits,
405 // Flags representing the nominal content of a type,
406 // computed by FlagsComputation. If you add a new nominal
407 // flag, it should be added here too.
408 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
409 TypeFlags::HAS_SELF.bits |
410 TypeFlags::HAS_TY_INFER.bits |
411 TypeFlags::HAS_RE_INFER.bits |
412 TypeFlags::HAS_RE_SKOL.bits |
413 TypeFlags::HAS_RE_EARLY_BOUND.bits |
414 TypeFlags::HAS_FREE_REGIONS.bits |
415 TypeFlags::HAS_TY_ERR.bits |
416 TypeFlags::HAS_PROJECTION.bits |
417 TypeFlags::HAS_TY_CLOSURE.bits |
418 TypeFlags::HAS_LOCAL_NAMES.bits |
419 TypeFlags::KEEP_IN_LOCAL_TCX.bits,
421 // Caches for type_is_sized, type_moves_by_default
422 const SIZEDNESS_CACHED = 1 << 16,
423 const IS_SIZED = 1 << 17,
424 const MOVENESS_CACHED = 1 << 18,
425 const MOVES_BY_DEFAULT = 1 << 19,
426 const FREEZENESS_CACHED = 1 << 20,
427 const IS_FREEZE = 1 << 21,
428 const NEEDS_DROP_CACHED = 1 << 22,
429 const NEEDS_DROP = 1 << 23,
433 pub struct TyS<'tcx> {
434 pub sty: TypeVariants<'tcx>,
435 pub flags: Cell<TypeFlags>,
437 // the maximal depth of any bound regions appearing in this type.
441 impl<'tcx> PartialEq for TyS<'tcx> {
443 fn eq(&self, other: &TyS<'tcx>) -> bool {
444 // (self as *const _) == (other as *const _)
445 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
448 impl<'tcx> Eq for TyS<'tcx> {}
450 impl<'tcx> Hash for TyS<'tcx> {
451 fn hash<H: Hasher>(&self, s: &mut H) {
452 (self as *const TyS).hash(s)
456 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for ty::TyS<'tcx> {
457 fn hash_stable<W: StableHasherResult>(&self,
458 hcx: &mut StableHashingContext<'a, 'tcx>,
459 hasher: &mut StableHasher<W>) {
463 // The other fields just provide fast access to information that is
464 // also contained in `sty`, so no need to hash them.
469 sty.hash_stable(hcx, hasher);
473 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
475 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
476 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
478 /// A wrapper for slices with the additional invariant
479 /// that the slice is interned and no other slice with
480 /// the same contents can exist in the same context.
481 /// This means we can use pointer + length for both
482 /// equality comparisons and hashing.
483 #[derive(Debug, RustcEncodable)]
484 pub struct Slice<T>([T]);
486 impl<T> PartialEq for Slice<T> {
488 fn eq(&self, other: &Slice<T>) -> bool {
489 (&self.0 as *const [T]) == (&other.0 as *const [T])
492 impl<T> Eq for Slice<T> {}
494 impl<T> Hash for Slice<T> {
495 fn hash<H: Hasher>(&self, s: &mut H) {
496 (self.as_ptr(), self.len()).hash(s)
500 impl<T> Deref for Slice<T> {
502 fn deref(&self) -> &[T] {
507 impl<'a, T> IntoIterator for &'a Slice<T> {
509 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
510 fn into_iter(self) -> Self::IntoIter {
515 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {}
518 pub fn empty<'a>() -> &'a Slice<T> {
520 mem::transmute(slice::from_raw_parts(0x1 as *const T, 0))
525 /// Upvars do not get their own node-id. Instead, we use the pair of
526 /// the original var id (that is, the root variable that is referenced
527 /// by the upvar) and the id of the closure expression.
528 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
531 pub closure_expr_id: NodeId,
534 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
535 pub enum BorrowKind {
536 /// Data must be immutable and is aliasable.
539 /// Data must be immutable but not aliasable. This kind of borrow
540 /// cannot currently be expressed by the user and is used only in
541 /// implicit closure bindings. It is needed when the closure
542 /// is borrowing or mutating a mutable referent, e.g.:
544 /// let x: &mut isize = ...;
545 /// let y = || *x += 5;
547 /// If we were to try to translate this closure into a more explicit
548 /// form, we'd encounter an error with the code as written:
550 /// struct Env { x: & &mut isize }
551 /// let x: &mut isize = ...;
552 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
553 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
555 /// This is then illegal because you cannot mutate a `&mut` found
556 /// in an aliasable location. To solve, you'd have to translate with
557 /// an `&mut` borrow:
559 /// struct Env { x: & &mut isize }
560 /// let x: &mut isize = ...;
561 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
562 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
564 /// Now the assignment to `**env.x` is legal, but creating a
565 /// mutable pointer to `x` is not because `x` is not mutable. We
566 /// could fix this by declaring `x` as `let mut x`. This is ok in
567 /// user code, if awkward, but extra weird for closures, since the
568 /// borrow is hidden.
570 /// So we introduce a "unique imm" borrow -- the referent is
571 /// immutable, but not aliasable. This solves the problem. For
572 /// simplicity, we don't give users the way to express this
573 /// borrow, it's just used when translating closures.
576 /// Data is mutable and not aliasable.
580 /// Information describing the capture of an upvar. This is computed
581 /// during `typeck`, specifically by `regionck`.
582 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
583 pub enum UpvarCapture<'tcx> {
584 /// Upvar is captured by value. This is always true when the
585 /// closure is labeled `move`, but can also be true in other cases
586 /// depending on inference.
589 /// Upvar is captured by reference.
590 ByRef(UpvarBorrow<'tcx>),
593 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
594 pub struct UpvarBorrow<'tcx> {
595 /// The kind of borrow: by-ref upvars have access to shared
596 /// immutable borrows, which are not part of the normal language
598 pub kind: BorrowKind,
600 /// Region of the resulting reference.
601 pub region: &'tcx ty::Region,
604 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
606 #[derive(Copy, Clone)]
607 pub struct ClosureUpvar<'tcx> {
613 #[derive(Clone, Copy, PartialEq)]
614 pub enum IntVarValue {
616 UintType(ast::UintTy),
619 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
620 pub struct TypeParameterDef {
624 pub has_default: bool,
625 pub object_lifetime_default: ObjectLifetimeDefault,
627 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
628 /// on generic parameter `T`, asserts data behind the parameter
629 /// `T` won't be accessed during the parent type's `Drop` impl.
630 pub pure_wrt_drop: bool,
633 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
634 pub struct RegionParameterDef {
638 pub issue_32330: Option<ty::Issue32330>,
640 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
641 /// on generic parameter `'a`, asserts data of lifetime `'a`
642 /// won't be accessed during the parent type's `Drop` impl.
643 pub pure_wrt_drop: bool,
646 impl RegionParameterDef {
647 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
648 ty::EarlyBoundRegion {
654 pub fn to_bound_region(&self) -> ty::BoundRegion {
655 ty::BoundRegion::BrNamed(self.def_id, self.name)
659 /// Information about the formal type/lifetime parameters associated
660 /// with an item or method. Analogous to hir::Generics.
661 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
662 pub struct Generics {
663 pub parent: Option<DefId>,
664 pub parent_regions: u32,
665 pub parent_types: u32,
666 pub regions: Vec<RegionParameterDef>,
667 pub types: Vec<TypeParameterDef>,
669 /// Reverse map to each `TypeParameterDef`'s `index` field, from
670 /// `def_id.index` (`def_id.krate` is the same as the item's).
671 pub type_param_to_index: BTreeMap<DefIndex, u32>,
677 pub fn parent_count(&self) -> usize {
678 self.parent_regions as usize + self.parent_types as usize
681 pub fn own_count(&self) -> usize {
682 self.regions.len() + self.types.len()
685 pub fn count(&self) -> usize {
686 self.parent_count() + self.own_count()
689 pub fn region_param(&self, param: &EarlyBoundRegion) -> &RegionParameterDef {
690 assert_eq!(self.parent_count(), 0);
691 &self.regions[param.index as usize - self.has_self as usize]
694 pub fn type_param(&self, param: &ParamTy) -> &TypeParameterDef {
695 assert_eq!(self.parent_count(), 0);
696 &self.types[param.idx as usize - self.has_self as usize - self.regions.len()]
700 /// Bounds on generics.
701 #[derive(Clone, Default)]
702 pub struct GenericPredicates<'tcx> {
703 pub parent: Option<DefId>,
704 pub predicates: Vec<Predicate<'tcx>>,
707 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
708 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
710 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
711 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
712 -> InstantiatedPredicates<'tcx> {
713 let mut instantiated = InstantiatedPredicates::empty();
714 self.instantiate_into(tcx, &mut instantiated, substs);
717 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
718 -> InstantiatedPredicates<'tcx> {
719 InstantiatedPredicates {
720 predicates: self.predicates.subst(tcx, substs)
724 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
725 instantiated: &mut InstantiatedPredicates<'tcx>,
726 substs: &Substs<'tcx>) {
727 if let Some(def_id) = self.parent {
728 tcx.item_predicates(def_id).instantiate_into(tcx, instantiated, substs);
730 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
733 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
734 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
735 -> InstantiatedPredicates<'tcx>
737 assert_eq!(self.parent, None);
738 InstantiatedPredicates {
739 predicates: self.predicates.iter().map(|pred| {
740 pred.subst_supertrait(tcx, poly_trait_ref)
746 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
747 pub enum Predicate<'tcx> {
748 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
749 /// the `Self` type of the trait reference and `A`, `B`, and `C`
750 /// would be the type parameters.
751 Trait(PolyTraitPredicate<'tcx>),
753 /// where `T1 == T2`.
754 Equate(PolyEquatePredicate<'tcx>),
757 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
760 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
762 /// where <T as TraitRef>::Name == X, approximately.
763 /// See `ProjectionPredicate` struct for details.
764 Projection(PolyProjectionPredicate<'tcx>),
767 WellFormed(Ty<'tcx>),
769 /// trait must be object-safe
772 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
773 /// for some substitutions `...` and T being a closure type.
774 /// Satisfied (or refuted) once we know the closure's kind.
775 ClosureKind(DefId, ClosureKind),
778 Subtype(PolySubtypePredicate<'tcx>),
781 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
782 /// Performs a substitution suitable for going from a
783 /// poly-trait-ref to supertraits that must hold if that
784 /// poly-trait-ref holds. This is slightly different from a normal
785 /// substitution in terms of what happens with bound regions. See
786 /// lengthy comment below for details.
787 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
788 trait_ref: &ty::PolyTraitRef<'tcx>)
789 -> ty::Predicate<'tcx>
791 // The interaction between HRTB and supertraits is not entirely
792 // obvious. Let me walk you (and myself) through an example.
794 // Let's start with an easy case. Consider two traits:
796 // trait Foo<'a> : Bar<'a,'a> { }
797 // trait Bar<'b,'c> { }
799 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
800 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
801 // knew that `Foo<'x>` (for any 'x) then we also know that
802 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
803 // normal substitution.
805 // In terms of why this is sound, the idea is that whenever there
806 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
807 // holds. So if there is an impl of `T:Foo<'a>` that applies to
808 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
811 // Another example to be careful of is this:
813 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
814 // trait Bar1<'b,'c> { }
816 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
817 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
818 // reason is similar to the previous example: any impl of
819 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
820 // basically we would want to collapse the bound lifetimes from
821 // the input (`trait_ref`) and the supertraits.
823 // To achieve this in practice is fairly straightforward. Let's
824 // consider the more complicated scenario:
826 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
827 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
828 // where both `'x` and `'b` would have a DB index of 1.
829 // The substitution from the input trait-ref is therefore going to be
830 // `'a => 'x` (where `'x` has a DB index of 1).
831 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
832 // early-bound parameter and `'b' is a late-bound parameter with a
834 // - If we replace `'a` with `'x` from the input, it too will have
835 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
836 // just as we wanted.
838 // There is only one catch. If we just apply the substitution `'a
839 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
840 // adjust the DB index because we substituting into a binder (it
841 // tries to be so smart...) resulting in `for<'x> for<'b>
842 // Bar1<'x,'b>` (we have no syntax for this, so use your
843 // imagination). Basically the 'x will have DB index of 2 and 'b
844 // will have DB index of 1. Not quite what we want. So we apply
845 // the substitution to the *contents* of the trait reference,
846 // rather than the trait reference itself (put another way, the
847 // substitution code expects equal binding levels in the values
848 // from the substitution and the value being substituted into, and
849 // this trick achieves that).
851 let substs = &trait_ref.0.substs;
853 Predicate::Trait(ty::Binder(ref data)) =>
854 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
855 Predicate::Equate(ty::Binder(ref data)) =>
856 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
857 Predicate::Subtype(ty::Binder(ref data)) =>
858 Predicate::Subtype(ty::Binder(data.subst(tcx, substs))),
859 Predicate::RegionOutlives(ty::Binder(ref data)) =>
860 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
861 Predicate::TypeOutlives(ty::Binder(ref data)) =>
862 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
863 Predicate::Projection(ty::Binder(ref data)) =>
864 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
865 Predicate::WellFormed(data) =>
866 Predicate::WellFormed(data.subst(tcx, substs)),
867 Predicate::ObjectSafe(trait_def_id) =>
868 Predicate::ObjectSafe(trait_def_id),
869 Predicate::ClosureKind(closure_def_id, kind) =>
870 Predicate::ClosureKind(closure_def_id, kind),
875 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
876 pub struct TraitPredicate<'tcx> {
877 pub trait_ref: TraitRef<'tcx>
879 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
881 impl<'tcx> TraitPredicate<'tcx> {
882 pub fn def_id(&self) -> DefId {
883 self.trait_ref.def_id
886 /// Creates the dep-node for selecting/evaluating this trait reference.
887 fn dep_node(&self) -> DepNode<DefId> {
888 // Extact the trait-def and first def-id from inputs. See the
889 // docs for `DepNode::TraitSelect` for more information.
890 let trait_def_id = self.def_id();
893 .flat_map(|t| t.walk())
894 .filter_map(|t| match t.sty {
895 ty::TyAdt(adt_def, _) => Some(adt_def.did),
899 .unwrap_or(trait_def_id);
900 DepNode::TraitSelect {
901 trait_def_id: trait_def_id,
902 input_def_id: input_def_id
906 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
907 self.trait_ref.input_types()
910 pub fn self_ty(&self) -> Ty<'tcx> {
911 self.trait_ref.self_ty()
915 impl<'tcx> PolyTraitPredicate<'tcx> {
916 pub fn def_id(&self) -> DefId {
917 // ok to skip binder since trait def-id does not care about regions
921 pub fn dep_node(&self) -> DepNode<DefId> {
922 // ok to skip binder since depnode does not care about regions
927 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
928 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
929 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
931 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
932 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
933 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
934 pub type PolyRegionOutlivesPredicate<'tcx> = PolyOutlivesPredicate<&'tcx ty::Region,
936 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, &'tcx ty::Region>;
938 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
939 pub struct SubtypePredicate<'tcx> {
940 pub a_is_expected: bool,
944 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
946 /// This kind of predicate has no *direct* correspondent in the
947 /// syntax, but it roughly corresponds to the syntactic forms:
949 /// 1. `T : TraitRef<..., Item=Type>`
950 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
952 /// In particular, form #1 is "desugared" to the combination of a
953 /// normal trait predicate (`T : TraitRef<...>`) and one of these
954 /// predicates. Form #2 is a broader form in that it also permits
955 /// equality between arbitrary types. Processing an instance of Form
956 /// #2 eventually yields one of these `ProjectionPredicate`
957 /// instances to normalize the LHS.
958 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
959 pub struct ProjectionPredicate<'tcx> {
960 pub projection_ty: ProjectionTy<'tcx>,
964 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
966 impl<'tcx> PolyProjectionPredicate<'tcx> {
967 pub fn item_name(&self) -> Name {
968 self.0.projection_ty.item_name // safe to skip the binder to access a name
972 pub trait ToPolyTraitRef<'tcx> {
973 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
976 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
977 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
978 assert!(!self.has_escaping_regions());
979 ty::Binder(self.clone())
983 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
984 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
985 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
989 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
990 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
991 // Note: unlike with TraitRef::to_poly_trait_ref(),
992 // self.0.trait_ref is permitted to have escaping regions.
993 // This is because here `self` has a `Binder` and so does our
994 // return value, so we are preserving the number of binding
996 ty::Binder(self.0.projection_ty.trait_ref)
1000 pub trait ToPredicate<'tcx> {
1001 fn to_predicate(&self) -> Predicate<'tcx>;
1004 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1005 fn to_predicate(&self) -> Predicate<'tcx> {
1006 // we're about to add a binder, so let's check that we don't
1007 // accidentally capture anything, or else that might be some
1008 // weird debruijn accounting.
1009 assert!(!self.has_escaping_regions());
1011 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
1012 trait_ref: self.clone()
1017 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1018 fn to_predicate(&self) -> Predicate<'tcx> {
1019 ty::Predicate::Trait(self.to_poly_trait_predicate())
1023 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
1024 fn to_predicate(&self) -> Predicate<'tcx> {
1025 Predicate::Equate(self.clone())
1029 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1030 fn to_predicate(&self) -> Predicate<'tcx> {
1031 Predicate::RegionOutlives(self.clone())
1035 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1036 fn to_predicate(&self) -> Predicate<'tcx> {
1037 Predicate::TypeOutlives(self.clone())
1041 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1042 fn to_predicate(&self) -> Predicate<'tcx> {
1043 Predicate::Projection(self.clone())
1047 impl<'tcx> Predicate<'tcx> {
1048 /// Iterates over the types in this predicate. Note that in all
1049 /// cases this is skipping over a binder, so late-bound regions
1050 /// with depth 0 are bound by the predicate.
1051 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1052 let vec: Vec<_> = match *self {
1053 ty::Predicate::Trait(ref data) => {
1054 data.skip_binder().input_types().collect()
1056 ty::Predicate::Equate(ty::Binder(ref data)) => {
1057 vec![data.0, data.1]
1059 ty::Predicate::Subtype(ty::Binder(SubtypePredicate { a, b, a_is_expected: _ })) => {
1062 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
1065 ty::Predicate::RegionOutlives(..) => {
1068 ty::Predicate::Projection(ref data) => {
1069 let trait_inputs = data.0.projection_ty.trait_ref.input_types();
1070 trait_inputs.chain(Some(data.0.ty)).collect()
1072 ty::Predicate::WellFormed(data) => {
1075 ty::Predicate::ObjectSafe(_trait_def_id) => {
1078 ty::Predicate::ClosureKind(_closure_def_id, _kind) => {
1083 // The only reason to collect into a vector here is that I was
1084 // too lazy to make the full (somewhat complicated) iterator
1085 // type that would be needed here. But I wanted this fn to
1086 // return an iterator conceptually, rather than a `Vec`, so as
1087 // to be closer to `Ty::walk`.
1091 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1093 Predicate::Trait(ref t) => {
1094 Some(t.to_poly_trait_ref())
1096 Predicate::Projection(..) |
1097 Predicate::Equate(..) |
1098 Predicate::Subtype(..) |
1099 Predicate::RegionOutlives(..) |
1100 Predicate::WellFormed(..) |
1101 Predicate::ObjectSafe(..) |
1102 Predicate::ClosureKind(..) |
1103 Predicate::TypeOutlives(..) => {
1110 /// Represents the bounds declared on a particular set of type
1111 /// parameters. Should eventually be generalized into a flag list of
1112 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1113 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1114 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1115 /// the `GenericPredicates` are expressed in terms of the bound type
1116 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1117 /// represented a set of bounds for some particular instantiation,
1118 /// meaning that the generic parameters have been substituted with
1123 /// struct Foo<T,U:Bar<T>> { ... }
1125 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1126 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1127 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1128 /// [usize:Bar<isize>]]`.
1130 pub struct InstantiatedPredicates<'tcx> {
1131 pub predicates: Vec<Predicate<'tcx>>,
1134 impl<'tcx> InstantiatedPredicates<'tcx> {
1135 pub fn empty() -> InstantiatedPredicates<'tcx> {
1136 InstantiatedPredicates { predicates: vec![] }
1139 pub fn is_empty(&self) -> bool {
1140 self.predicates.is_empty()
1144 /// When type checking, we use the `ParameterEnvironment` to track
1145 /// details about the type/lifetime parameters that are in scope.
1146 /// It primarily stores the bounds information.
1148 /// Note: This information might seem to be redundant with the data in
1149 /// `tcx.ty_param_defs`, but it is not. That table contains the
1150 /// parameter definitions from an "outside" perspective, but this
1151 /// struct will contain the bounds for a parameter as seen from inside
1152 /// the function body. Currently the only real distinction is that
1153 /// bound lifetime parameters are replaced with free ones, but in the
1154 /// future I hope to refine the representation of types so as to make
1155 /// more distinctions clearer.
1157 pub struct ParameterEnvironment<'tcx> {
1158 /// See `construct_free_substs` for details.
1159 pub free_substs: &'tcx Substs<'tcx>,
1161 /// Each type parameter has an implicit region bound that
1162 /// indicates it must outlive at least the function body (the user
1163 /// may specify stronger requirements). This field indicates the
1164 /// region of the callee.
1165 pub implicit_region_bound: &'tcx ty::Region,
1167 /// Obligations that the caller must satisfy. This is basically
1168 /// the set of bounds on the in-scope type parameters, translated
1169 /// into Obligations, and elaborated and normalized.
1170 pub caller_bounds: Vec<ty::Predicate<'tcx>>,
1172 /// Scope that is attached to free regions for this scope. This
1173 /// is usually the id of the fn body, but for more abstract scopes
1174 /// like structs we often use the node-id of the struct.
1176 /// FIXME(#3696). It would be nice to refactor so that free
1177 /// regions don't have this implicit scope and instead introduce
1178 /// relationships in the environment.
1179 pub free_id_outlive: CodeExtent,
1181 /// A cache for `moves_by_default`.
1182 pub is_copy_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1184 /// A cache for `type_is_sized`
1185 pub is_sized_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1187 /// A cache for `type_is_freeze`
1188 pub is_freeze_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1191 impl<'a, 'tcx> ParameterEnvironment<'tcx> {
1192 pub fn with_caller_bounds(&self,
1193 caller_bounds: Vec<ty::Predicate<'tcx>>)
1194 -> ParameterEnvironment<'tcx>
1196 ParameterEnvironment {
1197 free_substs: self.free_substs,
1198 implicit_region_bound: self.implicit_region_bound,
1199 caller_bounds: caller_bounds,
1200 free_id_outlive: self.free_id_outlive,
1201 is_copy_cache: RefCell::new(FxHashMap()),
1202 is_sized_cache: RefCell::new(FxHashMap()),
1203 is_freeze_cache: RefCell::new(FxHashMap()),
1207 /// Construct a parameter environment given an item, impl item, or trait item
1208 pub fn for_item(tcx: TyCtxt<'a, 'tcx, 'tcx>, id: NodeId)
1209 -> ParameterEnvironment<'tcx> {
1210 match tcx.hir.find(id) {
1211 Some(hir_map::NodeImplItem(ref impl_item)) => {
1212 match impl_item.node {
1213 hir::ImplItemKind::Type(_) | hir::ImplItemKind::Const(..) => {
1214 // associated types don't have their own entry (for some reason),
1215 // so for now just grab environment for the impl
1216 let impl_id = tcx.hir.get_parent(id);
1217 let impl_def_id = tcx.hir.local_def_id(impl_id);
1218 tcx.construct_parameter_environment(impl_item.span,
1220 tcx.region_maps.item_extent(id))
1222 hir::ImplItemKind::Method(_, ref body) => {
1223 tcx.construct_parameter_environment(
1225 tcx.hir.local_def_id(id),
1226 tcx.region_maps.call_site_extent(id, body.node_id))
1230 Some(hir_map::NodeTraitItem(trait_item)) => {
1231 match trait_item.node {
1232 hir::TraitItemKind::Type(..) | hir::TraitItemKind::Const(..) => {
1233 // associated types don't have their own entry (for some reason),
1234 // so for now just grab environment for the trait
1235 let trait_id = tcx.hir.get_parent(id);
1236 let trait_def_id = tcx.hir.local_def_id(trait_id);
1237 tcx.construct_parameter_environment(trait_item.span,
1239 tcx.region_maps.item_extent(id))
1241 hir::TraitItemKind::Method(_, ref body) => {
1242 // Use call-site for extent (unless this is a
1243 // trait method with no default; then fallback
1244 // to the method id).
1245 let extent = if let hir::TraitMethod::Provided(body_id) = *body {
1246 // default impl: use call_site extent as free_id_outlive bound.
1247 tcx.region_maps.call_site_extent(id, body_id.node_id)
1249 // no default impl: use item extent as free_id_outlive bound.
1250 tcx.region_maps.item_extent(id)
1252 tcx.construct_parameter_environment(
1254 tcx.hir.local_def_id(id),
1259 Some(hir_map::NodeItem(item)) => {
1261 hir::ItemFn(.., body_id) => {
1262 // We assume this is a function.
1263 let fn_def_id = tcx.hir.local_def_id(id);
1265 tcx.construct_parameter_environment(
1268 tcx.region_maps.call_site_extent(id, body_id.node_id))
1271 hir::ItemStruct(..) |
1272 hir::ItemUnion(..) |
1275 hir::ItemConst(..) |
1276 hir::ItemStatic(..) => {
1277 let def_id = tcx.hir.local_def_id(id);
1278 tcx.construct_parameter_environment(item.span,
1280 tcx.region_maps.item_extent(id))
1282 hir::ItemTrait(..) => {
1283 let def_id = tcx.hir.local_def_id(id);
1284 tcx.construct_parameter_environment(item.span,
1286 tcx.region_maps.item_extent(id))
1289 span_bug!(item.span,
1290 "ParameterEnvironment::for_item():
1291 can't create a parameter \
1292 environment for this kind of item")
1296 Some(hir_map::NodeExpr(expr)) => {
1297 // This is a convenience to allow closures to work.
1298 if let hir::ExprClosure(.., body, _) = expr.node {
1299 let def_id = tcx.hir.local_def_id(id);
1300 let base_def_id = tcx.closure_base_def_id(def_id);
1301 tcx.construct_parameter_environment(
1304 tcx.region_maps.call_site_extent(id, body.node_id))
1306 tcx.empty_parameter_environment()
1309 Some(hir_map::NodeForeignItem(item)) => {
1310 let def_id = tcx.hir.local_def_id(id);
1311 tcx.construct_parameter_environment(item.span,
1315 Some(hir_map::NodeStructCtor(..)) |
1316 Some(hir_map::NodeVariant(..)) => {
1317 let def_id = tcx.hir.local_def_id(id);
1318 tcx.construct_parameter_environment(tcx.hir.span(id),
1323 bug!("ParameterEnvironment::from_item(): \
1324 `{}` = {:?} is unsupported",
1325 tcx.hir.node_to_string(id), it)
1331 #[derive(Copy, Clone, Debug)]
1332 pub struct Destructor {
1333 /// The def-id of the destructor method
1335 /// Invoking the destructor of a dtorck type during usual cleanup
1336 /// (e.g. the glue emitted for stack unwinding) requires all
1337 /// lifetimes in the type-structure of `adt` to strictly outlive
1338 /// the adt value itself.
1340 /// If `adt` is not dtorck, then the adt's destructor can be
1341 /// invoked even when there are lifetimes in the type-structure of
1342 /// `adt` that do not strictly outlive the adt value itself.
1343 /// (This allows programs to make cyclic structures without
1344 /// resorting to unsafe means; see RFCs 769 and 1238).
1345 pub is_dtorck: bool,
1349 flags AdtFlags: u32 {
1350 const NO_ADT_FLAGS = 0,
1351 const IS_ENUM = 1 << 0,
1352 const IS_PHANTOM_DATA = 1 << 1,
1353 const IS_FUNDAMENTAL = 1 << 2,
1354 const IS_UNION = 1 << 3,
1355 const IS_BOX = 1 << 4,
1360 pub struct VariantDef {
1361 /// The variant's DefId. If this is a tuple-like struct,
1362 /// this is the DefId of the struct's ctor.
1364 pub name: Name, // struct's name if this is a struct
1365 pub discr: VariantDiscr,
1366 pub fields: Vec<FieldDef>,
1367 pub ctor_kind: CtorKind,
1370 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1371 pub enum VariantDiscr {
1372 /// Explicit value for this variant, i.e. `X = 123`.
1373 /// The `DefId` corresponds to the embedded constant.
1376 /// The previous variant's discriminant plus one.
1377 /// For efficiency reasons, the distance from the
1378 /// last `Explicit` discriminant is being stored,
1379 /// or `0` for the first variant, if it has none.
1384 pub struct FieldDef {
1387 pub vis: Visibility,
1390 /// The definition of an abstract data type - a struct or enum.
1392 /// These are all interned (by intern_adt_def) into the adt_defs
1396 pub variants: Vec<VariantDef>,
1398 pub repr: ReprOptions,
1401 impl PartialEq for AdtDef {
1402 // AdtDef are always interned and this is part of TyS equality
1404 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1407 impl Eq for AdtDef {}
1409 impl Hash for AdtDef {
1411 fn hash<H: Hasher>(&self, s: &mut H) {
1412 (self as *const AdtDef).hash(s)
1416 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1417 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1422 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1425 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for AdtDef {
1426 fn hash_stable<W: StableHasherResult>(&self,
1427 hcx: &mut StableHashingContext<'a, 'tcx>,
1428 hasher: &mut StableHasher<W>) {
1436 did.hash_stable(hcx, hasher);
1437 variants.hash_stable(hcx, hasher);
1438 flags.hash_stable(hcx, hasher);
1439 repr.hash_stable(hcx, hasher);
1443 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1444 pub enum AdtKind { Struct, Union, Enum }
1447 #[derive(RustcEncodable, RustcDecodable, Default)]
1448 flags ReprFlags: u8 {
1449 const IS_C = 1 << 0,
1450 const IS_PACKED = 1 << 1,
1451 const IS_SIMD = 1 << 2,
1452 // Internal only for now. If true, don't reorder fields.
1453 const IS_LINEAR = 1 << 3,
1455 // Any of these flags being set prevent field reordering optimisation.
1456 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1457 ReprFlags::IS_PACKED.bits |
1458 ReprFlags::IS_SIMD.bits |
1459 ReprFlags::IS_LINEAR.bits,
1463 impl_stable_hash_for!(struct ReprFlags {
1469 /// Represents the repr options provided by the user,
1470 #[derive(Copy, Clone, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1471 pub struct ReprOptions {
1472 pub int: Option<attr::IntType>,
1473 pub flags: ReprFlags,
1476 impl_stable_hash_for!(struct ReprOptions {
1482 pub fn new(tcx: TyCtxt, did: DefId) -> ReprOptions {
1483 let mut flags = ReprFlags::empty();
1484 let mut size = None;
1486 for attr in tcx.get_attrs(did).iter() {
1487 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1488 flags.insert(match r {
1489 attr::ReprExtern => ReprFlags::IS_C,
1490 attr::ReprPacked => ReprFlags::IS_PACKED,
1491 attr::ReprSimd => ReprFlags::IS_SIMD,
1492 attr::ReprInt(i) => {
1500 // FIXME(eddyb) This is deprecated and should be removed.
1501 if tcx.has_attr(did, "simd") {
1502 flags.insert(ReprFlags::IS_SIMD);
1505 // This is here instead of layout because the choice must make it into metadata.
1506 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1507 flags.insert(ReprFlags::IS_LINEAR);
1509 ReprOptions { int: size, flags: flags }
1513 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1515 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1517 pub fn packed(&self) -> bool { self.flags.contains(ReprFlags::IS_PACKED) }
1519 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1521 pub fn discr_type(&self) -> attr::IntType {
1522 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Is))
1525 /// Returns true if this `#[repr()]` should inhabit "smart enum
1526 /// layout" optimizations, such as representing `Foo<&T>` as a
1528 pub fn inhibit_enum_layout_opt(&self) -> bool {
1529 self.c() || self.int.is_some()
1533 impl<'a, 'gcx, 'tcx> AdtDef {
1537 variants: Vec<VariantDef>,
1538 repr: ReprOptions) -> Self {
1539 let mut flags = AdtFlags::NO_ADT_FLAGS;
1540 let attrs = tcx.get_attrs(did);
1541 if attr::contains_name(&attrs, "fundamental") {
1542 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1544 if Some(did) == tcx.lang_items.phantom_data() {
1545 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1547 if Some(did) == tcx.lang_items.owned_box() {
1548 flags = flags | AdtFlags::IS_BOX;
1551 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
1552 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
1553 AdtKind::Struct => {}
1564 pub fn is_struct(&self) -> bool {
1565 !self.is_union() && !self.is_enum()
1569 pub fn is_union(&self) -> bool {
1570 self.flags.intersects(AdtFlags::IS_UNION)
1574 pub fn is_enum(&self) -> bool {
1575 self.flags.intersects(AdtFlags::IS_ENUM)
1578 /// Returns the kind of the ADT - Struct or Enum.
1580 pub fn adt_kind(&self) -> AdtKind {
1583 } else if self.is_union() {
1590 pub fn descr(&self) -> &'static str {
1591 match self.adt_kind() {
1592 AdtKind::Struct => "struct",
1593 AdtKind::Union => "union",
1594 AdtKind::Enum => "enum",
1598 pub fn variant_descr(&self) -> &'static str {
1599 match self.adt_kind() {
1600 AdtKind::Struct => "struct",
1601 AdtKind::Union => "union",
1602 AdtKind::Enum => "variant",
1606 /// Returns whether this is a dtorck type. If this returns
1607 /// true, this type being safe for destruction requires it to be
1608 /// alive; Otherwise, only the contents are required to be.
1610 pub fn is_dtorck(&'gcx self, tcx: TyCtxt) -> bool {
1611 self.destructor(tcx).map_or(false, |d| d.is_dtorck)
1614 /// Returns whether this type is #[fundamental] for the purposes
1615 /// of coherence checking.
1617 pub fn is_fundamental(&self) -> bool {
1618 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
1621 /// Returns true if this is PhantomData<T>.
1623 pub fn is_phantom_data(&self) -> bool {
1624 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
1627 /// Returns true if this is Box<T>.
1629 pub fn is_box(&self) -> bool {
1630 self.flags.intersects(AdtFlags::IS_BOX)
1633 /// Returns whether this type has a destructor.
1634 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
1635 self.destructor(tcx).is_some()
1638 /// Asserts this is a struct and returns the struct's unique
1640 pub fn struct_variant(&self) -> &VariantDef {
1641 assert!(!self.is_enum());
1646 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
1647 tcx.item_predicates(self.did)
1650 /// Returns an iterator over all fields contained
1653 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
1654 self.variants.iter().flat_map(|v| v.fields.iter())
1658 pub fn is_univariant(&self) -> bool {
1659 self.variants.len() == 1
1662 pub fn is_payloadfree(&self) -> bool {
1663 !self.variants.is_empty() &&
1664 self.variants.iter().all(|v| v.fields.is_empty())
1667 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
1670 .find(|v| v.did == vid)
1671 .expect("variant_with_id: unknown variant")
1674 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1677 .position(|v| v.did == vid)
1678 .expect("variant_index_with_id: unknown variant")
1681 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
1683 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
1684 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
1685 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.struct_variant(),
1686 _ => bug!("unexpected def {:?} in variant_of_def", def)
1690 pub fn discriminants(&'a self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1691 -> impl Iterator<Item=ConstInt> + 'a {
1692 let repr_type = self.repr.discr_type();
1693 let initial = repr_type.initial_discriminant(tcx.global_tcx());
1694 let mut prev_discr = None::<ConstInt>;
1695 self.variants.iter().map(move |v| {
1696 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr());
1697 if let VariantDiscr::Explicit(expr_did) = v.discr {
1698 match queries::monomorphic_const_eval::get(tcx, DUMMY_SP, expr_did) {
1699 Ok(ConstVal::Integral(v)) => {
1705 prev_discr = Some(discr);
1711 /// Compute the discriminant value used by a specific variant.
1712 /// Unlike `discriminants`, this is (amortized) constant-time,
1713 /// only doing at most one query for evaluating an explicit
1714 /// discriminant (the last one before the requested variant),
1715 /// assuming there are no constant-evaluation errors there.
1716 pub fn discriminant_for_variant(&self,
1717 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1718 variant_index: usize)
1720 let repr_type = self.repr.discr_type();
1721 let mut explicit_value = repr_type.initial_discriminant(tcx.global_tcx());
1722 let mut explicit_index = variant_index;
1724 match self.variants[explicit_index].discr {
1725 ty::VariantDiscr::Relative(0) => break,
1726 ty::VariantDiscr::Relative(distance) => {
1727 explicit_index -= distance;
1729 ty::VariantDiscr::Explicit(expr_did) => {
1730 match queries::monomorphic_const_eval::get(tcx, DUMMY_SP, expr_did) {
1731 Ok(ConstVal::Integral(v)) => {
1736 explicit_index -= 1;
1742 let discr = explicit_value.to_u128_unchecked()
1743 .wrapping_add((variant_index - explicit_index) as u128);
1745 attr::UnsignedInt(ty) => {
1746 ConstInt::new_unsigned_truncating(discr, ty,
1747 tcx.sess.target.uint_type)
1749 attr::SignedInt(ty) => {
1750 ConstInt::new_signed_truncating(discr as i128, ty,
1751 tcx.sess.target.int_type)
1756 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
1757 queries::adt_destructor::get(tcx, DUMMY_SP, self.did)
1760 /// Returns a simpler type such that `Self: Sized` if and only
1761 /// if that type is Sized, or `TyErr` if this type is recursive.
1763 /// HACK: instead of returning a list of types, this function can
1764 /// return a tuple. In that case, the result is Sized only if
1765 /// all elements of the tuple are Sized.
1767 /// This is generally the `struct_tail` if this is a struct, or a
1768 /// tuple of them if this is an enum.
1770 /// Oddly enough, checking that the sized-constraint is Sized is
1771 /// actually more expressive than checking all members:
1772 /// the Sized trait is inductive, so an associated type that references
1773 /// Self would prevent its containing ADT from being Sized.
1775 /// Due to normalization being eager, this applies even if
1776 /// the associated type is behind a pointer, e.g. issue #31299.
1777 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Ty<'tcx> {
1778 match queries::adt_sized_constraint::try_get(tcx, DUMMY_SP, self.did) {
1781 debug!("adt_sized_constraint: {:?} is recursive", self);
1782 // This should be reported as an error by `check_representable`.
1784 // Consider the type as Sized in the meanwhile to avoid
1791 fn sized_constraint_for_ty(&self,
1792 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1795 let result = match ty.sty {
1796 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
1797 TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
1798 TyArray(..) | TyClosure(..) | TyNever => {
1802 TyStr | TyDynamic(..) | TySlice(_) | TyError => {
1803 // these are never sized - return the target type
1807 TyTuple(ref tys, _) => {
1810 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
1814 TyAdt(adt, substs) => {
1817 adt.sized_constraint(tcx)
1818 .subst(tcx, substs);
1819 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
1821 if let ty::TyTuple(ref tys, _) = adt_ty.sty {
1822 tys.iter().flat_map(|ty| {
1823 self.sized_constraint_for_ty(tcx, ty)
1826 self.sized_constraint_for_ty(tcx, adt_ty)
1830 TyProjection(..) | TyAnon(..) => {
1831 // must calculate explicitly.
1832 // FIXME: consider special-casing always-Sized projections
1837 // perf hack: if there is a `T: Sized` bound, then
1838 // we know that `T` is Sized and do not need to check
1841 let sized_trait = match tcx.lang_items.sized_trait() {
1843 _ => return vec![ty]
1845 let sized_predicate = Binder(TraitRef {
1846 def_id: sized_trait,
1847 substs: tcx.mk_substs_trait(ty, &[])
1849 let predicates = tcx.item_predicates(self.did).predicates;
1850 if predicates.into_iter().any(|p| p == sized_predicate) {
1858 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
1862 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
1867 impl<'a, 'gcx, 'tcx> VariantDef {
1869 pub fn find_field_named(&self,
1871 -> Option<&FieldDef> {
1872 self.fields.iter().find(|f| f.name == name)
1876 pub fn index_of_field_named(&self,
1879 self.fields.iter().position(|f| f.name == name)
1883 pub fn field_named(&self, name: ast::Name) -> &FieldDef {
1884 self.find_field_named(name).unwrap()
1888 impl<'a, 'gcx, 'tcx> FieldDef {
1889 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1890 tcx.item_type(self.did).subst(tcx, subst)
1894 /// Records the substitutions used to translate the polytype for an
1895 /// item into the monotype of an item reference.
1896 #[derive(Clone, RustcEncodable, RustcDecodable)]
1897 pub struct ItemSubsts<'tcx> {
1898 pub substs: &'tcx Substs<'tcx>,
1901 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1902 pub enum ClosureKind {
1903 // Warning: Ordering is significant here! The ordering is chosen
1904 // because the trait Fn is a subtrait of FnMut and so in turn, and
1905 // hence we order it so that Fn < FnMut < FnOnce.
1911 impl<'a, 'tcx> ClosureKind {
1912 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
1914 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
1915 ClosureKind::FnMut => {
1916 tcx.require_lang_item(FnMutTraitLangItem)
1918 ClosureKind::FnOnce => {
1919 tcx.require_lang_item(FnOnceTraitLangItem)
1924 /// True if this a type that impls this closure kind
1925 /// must also implement `other`.
1926 pub fn extends(self, other: ty::ClosureKind) -> bool {
1927 match (self, other) {
1928 (ClosureKind::Fn, ClosureKind::Fn) => true,
1929 (ClosureKind::Fn, ClosureKind::FnMut) => true,
1930 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
1931 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
1932 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
1933 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
1939 impl<'tcx> TyS<'tcx> {
1940 /// Iterator that walks `self` and any types reachable from
1941 /// `self`, in depth-first order. Note that just walks the types
1942 /// that appear in `self`, it does not descend into the fields of
1943 /// structs or variants. For example:
1946 /// isize => { isize }
1947 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
1948 /// [isize] => { [isize], isize }
1950 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
1951 TypeWalker::new(self)
1954 /// Iterator that walks the immediate children of `self`. Hence
1955 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
1956 /// (but not `i32`, like `walk`).
1957 pub fn walk_shallow(&'tcx self) -> AccIntoIter<walk::TypeWalkerArray<'tcx>> {
1958 walk::walk_shallow(self)
1961 /// Walks `ty` and any types appearing within `ty`, invoking the
1962 /// callback `f` on each type. If the callback returns false, then the
1963 /// children of the current type are ignored.
1965 /// Note: prefer `ty.walk()` where possible.
1966 pub fn maybe_walk<F>(&'tcx self, mut f: F)
1967 where F : FnMut(Ty<'tcx>) -> bool
1969 let mut walker = self.walk();
1970 while let Some(ty) = walker.next() {
1972 walker.skip_current_subtree();
1978 impl<'tcx> ItemSubsts<'tcx> {
1979 pub fn is_noop(&self) -> bool {
1980 self.substs.is_noop()
1984 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1985 pub enum LvaluePreference {
1990 impl LvaluePreference {
1991 pub fn from_mutbl(m: hir::Mutability) -> Self {
1993 hir::MutMutable => PreferMutLvalue,
1994 hir::MutImmutable => NoPreference,
2000 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2002 hir::MutMutable => MutBorrow,
2003 hir::MutImmutable => ImmBorrow,
2007 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2008 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2009 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2011 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2013 MutBorrow => hir::MutMutable,
2014 ImmBorrow => hir::MutImmutable,
2016 // We have no type corresponding to a unique imm borrow, so
2017 // use `&mut`. It gives all the capabilities of an `&uniq`
2018 // and hence is a safe "over approximation".
2019 UniqueImmBorrow => hir::MutMutable,
2023 pub fn to_user_str(&self) -> &'static str {
2025 MutBorrow => "mutable",
2026 ImmBorrow => "immutable",
2027 UniqueImmBorrow => "uniquely immutable",
2032 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2033 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2034 self.item_tables(self.hir.body_owner_def_id(body))
2037 pub fn item_tables(self, def_id: DefId) -> &'gcx TypeckTables<'gcx> {
2038 queries::typeck_tables::get(self, DUMMY_SP, def_id)
2041 pub fn expr_span(self, id: NodeId) -> Span {
2042 match self.hir.find(id) {
2043 Some(hir_map::NodeExpr(e)) => {
2047 bug!("Node id {} is not an expr: {:?}", id, f);
2050 bug!("Node id {} is not present in the node map", id);
2055 pub fn local_var_name_str(self, id: NodeId) -> InternedString {
2056 match self.hir.find(id) {
2057 Some(hir_map::NodeLocal(pat)) => {
2059 hir::PatKind::Binding(_, _, ref path1, _) => path1.node.as_str(),
2061 bug!("Variable id {} maps to {:?}, not local", id, pat);
2065 r => bug!("Variable id {} maps to {:?}, not local", id, r),
2069 pub fn expr_is_lval(self, expr: &hir::Expr) -> bool {
2071 hir::ExprPath(hir::QPath::Resolved(_, ref path)) => {
2073 Def::Local(..) | Def::Upvar(..) | Def::Static(..) | Def::Err => true,
2078 hir::ExprType(ref e, _) => {
2079 self.expr_is_lval(e)
2082 hir::ExprUnary(hir::UnDeref, _) |
2083 hir::ExprField(..) |
2084 hir::ExprTupField(..) |
2085 hir::ExprIndex(..) => {
2089 // Partially qualified paths in expressions can only legally
2090 // refer to associated items which are always rvalues.
2091 hir::ExprPath(hir::QPath::TypeRelative(..)) |
2094 hir::ExprMethodCall(..) |
2095 hir::ExprStruct(..) |
2098 hir::ExprMatch(..) |
2099 hir::ExprClosure(..) |
2100 hir::ExprBlock(..) |
2101 hir::ExprRepeat(..) |
2102 hir::ExprArray(..) |
2103 hir::ExprBreak(..) |
2104 hir::ExprAgain(..) |
2106 hir::ExprWhile(..) |
2108 hir::ExprAssign(..) |
2109 hir::ExprInlineAsm(..) |
2110 hir::ExprAssignOp(..) |
2112 hir::ExprUnary(..) |
2114 hir::ExprAddrOf(..) |
2115 hir::ExprBinary(..) |
2116 hir::ExprCast(..) => {
2122 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2123 self.associated_items(id)
2124 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2128 pub fn trait_impl_polarity(self, id: DefId) -> hir::ImplPolarity {
2129 if let Some(id) = self.hir.as_local_node_id(id) {
2130 match self.hir.expect_item(id).node {
2131 hir::ItemImpl(_, polarity, ..) => polarity,
2132 ref item => bug!("trait_impl_polarity: {:?} not an impl", item)
2135 self.sess.cstore.impl_polarity(id)
2139 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2140 self.associated_items(did).any(|item| {
2141 item.relevant_for_never()
2145 pub fn coerce_unsized_info(self, did: DefId) -> adjustment::CoerceUnsizedInfo {
2146 queries::coerce_unsized_info::get(self, DUMMY_SP, did)
2149 pub fn associated_item(self, def_id: DefId) -> AssociatedItem {
2150 queries::associated_item::get(self, DUMMY_SP, def_id)
2153 fn associated_item_from_trait_item_ref(self,
2154 parent_def_id: DefId,
2155 trait_item_ref: &hir::TraitItemRef)
2157 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2158 let (kind, has_self) = match trait_item_ref.kind {
2159 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2160 hir::AssociatedItemKind::Method { has_self } => {
2161 (ty::AssociatedKind::Method, has_self)
2163 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2167 name: trait_item_ref.name,
2169 vis: Visibility::from_hir(&hir::Inherited, trait_item_ref.id.node_id, self),
2170 defaultness: trait_item_ref.defaultness,
2172 container: TraitContainer(parent_def_id),
2173 method_has_self_argument: has_self
2177 fn associated_item_from_impl_item_ref(self,
2178 parent_def_id: DefId,
2179 from_trait_impl: bool,
2180 impl_item_ref: &hir::ImplItemRef)
2182 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2183 let (kind, has_self) = match impl_item_ref.kind {
2184 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2185 hir::AssociatedItemKind::Method { has_self } => {
2186 (ty::AssociatedKind::Method, has_self)
2188 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2191 // Trait impl items are always public.
2192 let public = hir::Public;
2193 let vis = if from_trait_impl { &public } else { &impl_item_ref.vis };
2195 ty::AssociatedItem {
2196 name: impl_item_ref.name,
2198 vis: ty::Visibility::from_hir(vis, impl_item_ref.id.node_id, self),
2199 defaultness: impl_item_ref.defaultness,
2201 container: ImplContainer(parent_def_id),
2202 method_has_self_argument: has_self
2206 pub fn associated_item_def_ids(self, def_id: DefId) -> Rc<Vec<DefId>> {
2207 queries::associated_item_def_ids::get(self, DUMMY_SP, def_id)
2210 #[inline] // FIXME(#35870) Avoid closures being unexported due to impl Trait.
2211 pub fn associated_items(self, def_id: DefId)
2212 -> impl Iterator<Item = ty::AssociatedItem> + 'a {
2213 let def_ids = self.associated_item_def_ids(def_id);
2214 (0..def_ids.len()).map(move |i| self.associated_item(def_ids[i]))
2217 /// Returns the trait-ref corresponding to a given impl, or None if it is
2218 /// an inherent impl.
2219 pub fn impl_trait_ref(self, id: DefId) -> Option<TraitRef<'gcx>> {
2220 queries::impl_trait_ref::get(self, DUMMY_SP, id)
2223 /// Returns true if the impls are the same polarity and are implementing
2224 /// a trait which contains no items
2225 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2226 if !self.sess.features.borrow().overlapping_marker_traits {
2229 let trait1_is_empty = self.impl_trait_ref(def_id1)
2230 .map_or(false, |trait_ref| {
2231 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2233 let trait2_is_empty = self.impl_trait_ref(def_id2)
2234 .map_or(false, |trait_ref| {
2235 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2237 self.trait_impl_polarity(def_id1) == self.trait_impl_polarity(def_id2)
2242 // Returns `ty::VariantDef` if `def` refers to a struct,
2243 // or variant or their constructors, panics otherwise.
2244 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2246 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2247 let enum_did = self.parent_def_id(did).unwrap();
2248 self.lookup_adt_def(enum_did).variant_with_id(did)
2250 Def::Struct(did) | Def::Union(did) => {
2251 self.lookup_adt_def(did).struct_variant()
2253 Def::StructCtor(ctor_did, ..) => {
2254 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2255 self.lookup_adt_def(did).struct_variant()
2257 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2261 pub fn def_key(self, id: DefId) -> hir_map::DefKey {
2263 self.hir.def_key(id)
2265 self.sess.cstore.def_key(id)
2269 /// Convert a `DefId` into its fully expanded `DefPath` (every
2270 /// `DefId` is really just an interned def-path).
2272 /// Note that if `id` is not local to this crate, the result will
2273 /// be a non-local `DefPath`.
2274 pub fn def_path(self, id: DefId) -> hir_map::DefPath {
2276 self.hir.def_path(id)
2278 self.sess.cstore.def_path(id)
2283 pub fn def_path_hash(self, def_id: DefId) -> u64 {
2284 if def_id.is_local() {
2285 self.hir.definitions().def_path_hash(def_id.index)
2287 self.sess.cstore.def_path_hash(def_id)
2291 pub fn def_span(self, def_id: DefId) -> Span {
2292 if let Some(id) = self.hir.as_local_node_id(def_id) {
2295 self.sess.cstore.def_span(&self.sess, def_id)
2299 pub fn vis_is_accessible_from(self, vis: Visibility, block: NodeId) -> bool {
2300 vis.is_accessible_from(self.hir.local_def_id(self.hir.get_module_parent(block)), self)
2303 pub fn item_name(self, id: DefId) -> ast::Name {
2304 if let Some(id) = self.hir.as_local_node_id(id) {
2306 } else if id.index == CRATE_DEF_INDEX {
2307 self.sess.cstore.original_crate_name(id.krate)
2309 let def_key = self.sess.cstore.def_key(id);
2310 // The name of a StructCtor is that of its struct parent.
2311 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2312 self.item_name(DefId {
2314 index: def_key.parent.unwrap()
2317 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2318 bug!("item_name: no name for {:?}", self.def_path(id));
2324 // If the given item is in an external crate, looks up its type and adds it to
2325 // the type cache. Returns the type parameters and type.
2326 pub fn item_type(self, did: DefId) -> Ty<'gcx> {
2327 queries::ty::get(self, DUMMY_SP, did)
2330 /// Given the did of a trait, returns its canonical trait ref.
2331 pub fn lookup_trait_def(self, did: DefId) -> &'gcx TraitDef {
2332 queries::trait_def::get(self, DUMMY_SP, did)
2335 /// Given the did of an ADT, return a reference to its definition.
2336 pub fn lookup_adt_def(self, did: DefId) -> &'gcx AdtDef {
2337 queries::adt_def::get(self, DUMMY_SP, did)
2340 /// Given the did of an item, returns its generics.
2341 pub fn item_generics(self, did: DefId) -> &'gcx Generics {
2342 queries::generics::get(self, DUMMY_SP, did)
2345 /// Given the did of an item, returns its full set of predicates.
2346 pub fn item_predicates(self, did: DefId) -> GenericPredicates<'gcx> {
2347 queries::predicates::get(self, DUMMY_SP, did)
2350 /// Given the did of a trait, returns its superpredicates.
2351 pub fn item_super_predicates(self, did: DefId) -> GenericPredicates<'gcx> {
2352 queries::super_predicates::get(self, DUMMY_SP, did)
2355 /// Given the did of an item, returns its MIR, borrowed immutably.
2356 pub fn item_mir(self, did: DefId) -> Ref<'gcx, Mir<'gcx>> {
2357 queries::mir::get(self, DUMMY_SP, did).borrow()
2360 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2361 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2362 -> Ref<'gcx, Mir<'gcx>>
2365 ty::InstanceDef::Item(did) if true => self.item_mir(did),
2366 _ => queries::mir_shims::get(self, DUMMY_SP, instance).borrow(),
2370 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2371 /// Returns None if there is no MIR for the DefId
2372 pub fn maybe_item_mir(self, did: DefId) -> Option<Ref<'gcx, Mir<'gcx>>> {
2373 if did.is_local() && !self.maps.mir.borrow().contains_key(&did) {
2377 if !did.is_local() && !self.sess.cstore.is_item_mir_available(did) {
2381 Some(self.item_mir(did))
2384 /// Get the attributes of a definition.
2385 pub fn get_attrs(self, did: DefId) -> Cow<'gcx, [ast::Attribute]> {
2386 if let Some(id) = self.hir.as_local_node_id(did) {
2387 Cow::Borrowed(self.hir.attrs(id))
2389 Cow::Owned(self.sess.cstore.item_attrs(did))
2393 /// Determine whether an item is annotated with an attribute
2394 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2395 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2398 pub fn item_variances(self, item_id: DefId) -> Rc<Vec<ty::Variance>> {
2399 queries::variances::get(self, DUMMY_SP, item_id)
2402 pub fn trait_has_default_impl(self, trait_def_id: DefId) -> bool {
2403 let def = self.lookup_trait_def(trait_def_id);
2404 def.flags.get().intersects(TraitFlags::HAS_DEFAULT_IMPL)
2407 /// Populates the type context with all the implementations for the given
2408 /// trait if necessary.
2409 pub fn populate_implementations_for_trait_if_necessary(self, trait_id: DefId) {
2410 if trait_id.is_local() {
2414 // The type is not local, hence we are reading this out of
2415 // metadata and don't need to track edges.
2416 let _ignore = self.dep_graph.in_ignore();
2418 let def = self.lookup_trait_def(trait_id);
2419 if def.flags.get().intersects(TraitFlags::HAS_REMOTE_IMPLS) {
2423 debug!("populate_implementations_for_trait_if_necessary: searching for {:?}", def);
2425 for impl_def_id in self.sess.cstore.implementations_of_trait(Some(trait_id)) {
2426 let trait_ref = self.impl_trait_ref(impl_def_id).unwrap();
2428 // Record the trait->implementation mapping.
2429 let parent = self.sess.cstore.impl_parent(impl_def_id).unwrap_or(trait_id);
2430 def.record_remote_impl(self, impl_def_id, trait_ref, parent);
2433 def.flags.set(def.flags.get() | TraitFlags::HAS_REMOTE_IMPLS);
2436 pub fn closure_kind(self, def_id: DefId) -> ty::ClosureKind {
2437 queries::closure_kind::get(self, DUMMY_SP, def_id)
2440 pub fn closure_type(self, def_id: DefId) -> ty::PolyFnSig<'tcx> {
2441 queries::closure_type::get(self, DUMMY_SP, def_id)
2444 /// Given the def_id of an impl, return the def_id of the trait it implements.
2445 /// If it implements no trait, return `None`.
2446 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2447 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2450 /// If the given def ID describes a method belonging to an impl, return the
2451 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2452 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2453 let item = if def_id.krate != LOCAL_CRATE {
2454 if let Some(Def::Method(_)) = self.sess.cstore.describe_def(def_id) {
2455 Some(self.associated_item(def_id))
2460 self.maps.associated_item.borrow().get(&def_id).cloned()
2464 Some(trait_item) => {
2465 match trait_item.container {
2466 TraitContainer(_) => None,
2467 ImplContainer(def_id) => Some(def_id),
2474 /// If the given def ID describes an item belonging to a trait,
2475 /// return the ID of the trait that the trait item belongs to.
2476 /// Otherwise, return `None`.
2477 pub fn trait_of_item(self, def_id: DefId) -> Option<DefId> {
2478 if def_id.krate != LOCAL_CRATE {
2479 return self.sess.cstore.trait_of_item(def_id);
2481 match self.maps.associated_item.borrow().get(&def_id) {
2482 Some(associated_item) => {
2483 match associated_item.container {
2484 TraitContainer(def_id) => Some(def_id),
2485 ImplContainer(_) => None
2492 /// Construct a parameter environment suitable for static contexts or other contexts where there
2493 /// are no free type/lifetime parameters in scope.
2494 pub fn empty_parameter_environment(self) -> ParameterEnvironment<'tcx> {
2496 // for an empty parameter environment, there ARE no free
2497 // regions, so it shouldn't matter what we use for the free id
2498 let free_id_outlive = self.region_maps.node_extent(ast::DUMMY_NODE_ID);
2499 ty::ParameterEnvironment {
2500 free_substs: self.intern_substs(&[]),
2501 caller_bounds: Vec::new(),
2502 implicit_region_bound: self.mk_region(ty::ReEmpty),
2503 free_id_outlive: free_id_outlive,
2504 is_copy_cache: RefCell::new(FxHashMap()),
2505 is_sized_cache: RefCell::new(FxHashMap()),
2506 is_freeze_cache: RefCell::new(FxHashMap()),
2510 /// Constructs and returns a substitution that can be applied to move from
2511 /// the "outer" view of a type or method to the "inner" view.
2512 /// In general, this means converting from bound parameters to
2513 /// free parameters. Since we currently represent bound/free type
2514 /// parameters in the same way, this only has an effect on regions.
2515 pub fn construct_free_substs(self, def_id: DefId,
2516 free_id_outlive: CodeExtent)
2517 -> &'gcx Substs<'gcx> {
2519 let substs = Substs::for_item(self.global_tcx(), def_id, |def, _| {
2520 // map bound 'a => free 'a
2521 self.global_tcx().mk_region(ReFree(FreeRegion {
2522 scope: free_id_outlive,
2523 bound_region: def.to_bound_region()
2527 self.global_tcx().mk_param_from_def(def)
2530 debug!("construct_parameter_environment: {:?}", substs);
2534 /// See `ParameterEnvironment` struct def'n for details.
2535 /// If you were using `free_id: NodeId`, you might try `self.region_maps.item_extent(free_id)`
2536 /// for the `free_id_outlive` parameter. (But note that this is not always quite right.)
2537 pub fn construct_parameter_environment(self,
2540 free_id_outlive: CodeExtent)
2541 -> ParameterEnvironment<'gcx>
2544 // Construct the free substs.
2547 let free_substs = self.construct_free_substs(def_id, free_id_outlive);
2550 // Compute the bounds on Self and the type parameters.
2553 let tcx = self.global_tcx();
2554 let generic_predicates = tcx.item_predicates(def_id);
2555 let bounds = generic_predicates.instantiate(tcx, free_substs);
2556 let bounds = tcx.liberate_late_bound_regions(free_id_outlive, &ty::Binder(bounds));
2557 let predicates = bounds.predicates;
2559 // Finally, we have to normalize the bounds in the environment, in
2560 // case they contain any associated type projections. This process
2561 // can yield errors if the put in illegal associated types, like
2562 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2563 // report these errors right here; this doesn't actually feel
2564 // right to me, because constructing the environment feels like a
2565 // kind of a "idempotent" action, but I'm not sure where would be
2566 // a better place. In practice, we construct environments for
2567 // every fn once during type checking, and we'll abort if there
2568 // are any errors at that point, so after type checking you can be
2569 // sure that this will succeed without errors anyway.
2572 let unnormalized_env = ty::ParameterEnvironment {
2573 free_substs: free_substs,
2574 implicit_region_bound: tcx.mk_region(ty::ReScope(free_id_outlive)),
2575 caller_bounds: predicates,
2576 free_id_outlive: free_id_outlive,
2577 is_copy_cache: RefCell::new(FxHashMap()),
2578 is_sized_cache: RefCell::new(FxHashMap()),
2579 is_freeze_cache: RefCell::new(FxHashMap()),
2582 let cause = traits::ObligationCause::misc(span, free_id_outlive.node_id(&self.region_maps));
2583 traits::normalize_param_env_or_error(tcx, unnormalized_env, cause)
2586 pub fn node_scope_region(self, id: NodeId) -> &'tcx Region {
2587 self.mk_region(ty::ReScope(self.region_maps.node_extent(id)))
2590 pub fn visit_all_item_likes_in_krate<V,F>(self,
2593 where F: FnMut(DefId) -> DepNode<DefId>, V: ItemLikeVisitor<'gcx>
2595 dep_graph::visit_all_item_likes_in_krate(self.global_tcx(), dep_node_fn, visitor);
2598 /// Invokes `callback` for each body in the krate. This will
2599 /// create a read edge from `DepNode::Krate` to the current task;
2600 /// it is meant to be run in the context of some global task like
2601 /// `BorrowckCrate`. The callback would then create a task like
2602 /// `BorrowckBody(DefId)` to process each individual item.
2603 pub fn visit_all_bodies_in_krate<C>(self, callback: C)
2604 where C: Fn(/* body_owner */ DefId, /* body id */ hir::BodyId),
2606 dep_graph::visit_all_bodies_in_krate(self.global_tcx(), callback)
2609 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2610 /// with the name of the crate containing the impl.
2611 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2612 if impl_did.is_local() {
2613 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2614 Ok(self.hir.span(node_id))
2616 Err(self.sess.cstore.crate_name(impl_did.krate))
2621 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2622 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2623 F: FnOnce(&[hir::Freevar]) -> T,
2625 match self.freevars.borrow().get(&fid) {
2627 Some(d) => f(&d[..])
2632 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
2635 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2636 let parent_id = tcx.hir.get_parent(id);
2637 let parent_def_id = tcx.hir.local_def_id(parent_id);
2638 let parent_item = tcx.hir.expect_item(parent_id);
2639 match parent_item.node {
2640 hir::ItemImpl(.., ref impl_trait_ref, _, ref impl_item_refs) => {
2641 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2643 tcx.associated_item_from_impl_item_ref(parent_def_id,
2644 impl_trait_ref.is_some(),
2646 debug_assert_eq!(assoc_item.def_id, def_id);
2651 hir::ItemTrait(.., ref trait_item_refs) => {
2652 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2654 tcx.associated_item_from_trait_item_ref(parent_def_id, trait_item_ref);
2655 debug_assert_eq!(assoc_item.def_id, def_id);
2661 panic!("unexpected container of associated items: {:?}", r)
2664 panic!("associated item not found for def_id: {:?}", def_id);
2667 /// Calculates the Sized-constraint.
2669 /// As the Sized-constraint of enums can be a *set* of types,
2670 /// the Sized-constraint may need to be a set also. Because introducing
2671 /// a new type of IVar is currently a complex affair, the Sized-constraint
2674 /// In fact, there are only a few options for the constraint:
2675 /// - `bool`, if the type is always Sized
2676 /// - an obviously-unsized type
2677 /// - a type parameter or projection whose Sizedness can't be known
2678 /// - a tuple of type parameters or projections, if there are multiple
2680 /// - a TyError, if a type contained itself. The representability
2681 /// check should catch this case.
2682 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2685 let def = tcx.lookup_adt_def(def_id);
2687 let tys: Vec<_> = def.variants.iter().flat_map(|v| {
2690 let ty = tcx.item_type(f.did);
2691 def.sized_constraint_for_ty(tcx, ty)
2694 let ty = match tys.len() {
2695 _ if tys.references_error() => tcx.types.err,
2696 0 => tcx.types.bool,
2698 _ => tcx.intern_tup(&tys[..], false)
2701 debug!("adt_sized_constraint: {:?} => {:?}", def, ty);
2706 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2709 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2710 let item = tcx.hir.expect_item(id);
2711 let vec: Vec<_> = match item.node {
2712 hir::ItemTrait(.., ref trait_item_refs) => {
2713 trait_item_refs.iter()
2714 .map(|trait_item_ref| trait_item_ref.id)
2715 .map(|id| tcx.hir.local_def_id(id.node_id))
2718 hir::ItemImpl(.., ref impl_item_refs) => {
2719 impl_item_refs.iter()
2720 .map(|impl_item_ref| impl_item_ref.id)
2721 .map(|id| tcx.hir.local_def_id(id.node_id))
2724 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2729 pub fn provide(providers: &mut ty::maps::Providers) {
2730 *providers = ty::maps::Providers {
2732 associated_item_def_ids,
2733 adt_sized_constraint,
2738 pub fn provide_extern(providers: &mut ty::maps::Providers) {
2739 *providers = ty::maps::Providers {
2740 adt_sized_constraint,
2746 /// A map for the local crate mapping each type to a vector of its
2747 /// inherent impls. This is not meant to be used outside of coherence;
2748 /// rather, you should request the vector for a specific type via
2749 /// `ty::queries::inherent_impls::get(def_id)` so as to minimize your
2750 /// dependencies (constructing this map requires touching the entire
2752 #[derive(Clone, Debug)]
2753 pub struct CrateInherentImpls {
2754 pub inherent_impls: DefIdMap<Rc<Vec<DefId>>>,