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::contents::TypeContents;
75 pub use self::context::{TyCtxt, GlobalArenas, tls};
76 pub use self::context::{Lift, TypeckTables};
78 pub use self::instance::{Instance, InstanceDef};
80 pub use self::trait_def::{TraitDef, TraitFlags};
82 pub use self::maps::queries;
89 pub mod inhabitedness;
106 mod structural_impls;
111 /// The complete set of all analyses described in this module. This is
112 /// produced by the driver and fed to trans and later passes.
114 /// NB: These contents are being migrated into queries using the
115 /// *on-demand* infrastructure.
117 pub struct CrateAnalysis {
118 pub access_levels: Rc<AccessLevels>,
119 pub reachable: NodeSet,
121 pub glob_map: Option<hir::GlobMap>,
125 pub struct Resolutions {
126 pub freevars: FreevarMap,
127 pub trait_map: TraitMap,
128 pub maybe_unused_trait_imports: NodeSet,
129 pub export_map: ExportMap,
132 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
133 pub enum AssociatedItemContainer {
134 TraitContainer(DefId),
135 ImplContainer(DefId),
138 impl AssociatedItemContainer {
139 pub fn id(&self) -> DefId {
141 TraitContainer(id) => id,
142 ImplContainer(id) => id,
147 /// The "header" of an impl is everything outside the body: a Self type, a trait
148 /// ref (in the case of a trait impl), and a set of predicates (from the
149 /// bounds/where clauses).
150 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
151 pub struct ImplHeader<'tcx> {
152 pub impl_def_id: DefId,
153 pub self_ty: Ty<'tcx>,
154 pub trait_ref: Option<TraitRef<'tcx>>,
155 pub predicates: Vec<Predicate<'tcx>>,
158 impl<'a, 'gcx, 'tcx> ImplHeader<'tcx> {
159 pub fn with_fresh_ty_vars(selcx: &mut traits::SelectionContext<'a, 'gcx, 'tcx>,
163 let tcx = selcx.tcx();
164 let impl_substs = selcx.infcx().fresh_substs_for_item(DUMMY_SP, impl_def_id);
166 let header = ImplHeader {
167 impl_def_id: impl_def_id,
168 self_ty: tcx.item_type(impl_def_id),
169 trait_ref: tcx.impl_trait_ref(impl_def_id),
170 predicates: tcx.item_predicates(impl_def_id).predicates
171 }.subst(tcx, impl_substs);
173 let traits::Normalized { value: mut header, obligations } =
174 traits::normalize(selcx, traits::ObligationCause::dummy(), &header);
176 header.predicates.extend(obligations.into_iter().map(|o| o.predicate));
181 #[derive(Copy, Clone, Debug)]
182 pub struct AssociatedItem {
185 pub kind: AssociatedKind,
187 pub defaultness: hir::Defaultness,
188 pub container: AssociatedItemContainer,
190 /// Whether this is a method with an explicit self
191 /// as its first argument, allowing method calls.
192 pub method_has_self_argument: bool,
195 #[derive(Copy, Clone, PartialEq, Eq, Debug, RustcEncodable, RustcDecodable)]
196 pub enum AssociatedKind {
202 impl AssociatedItem {
203 pub fn def(&self) -> Def {
205 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
206 AssociatedKind::Method => Def::Method(self.def_id),
207 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
211 /// Tests whether the associated item admits a non-trivial implementation
213 pub fn relevant_for_never<'tcx>(&self) -> bool {
215 AssociatedKind::Const => true,
216 AssociatedKind::Type => true,
217 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
218 AssociatedKind::Method => !self.method_has_self_argument,
223 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
224 pub enum Visibility {
225 /// Visible everywhere (including in other crates).
227 /// Visible only in the given crate-local module.
229 /// Not visible anywhere in the local crate. This is the visibility of private external items.
233 pub trait DefIdTree: Copy {
234 fn parent(self, id: DefId) -> Option<DefId>;
236 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
237 if descendant.krate != ancestor.krate {
241 while descendant != ancestor {
242 match self.parent(descendant) {
243 Some(parent) => descendant = parent,
244 None => return false,
251 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
252 fn parent(self, id: DefId) -> Option<DefId> {
253 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
258 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt) -> Self {
260 hir::Public => Visibility::Public,
261 hir::Visibility::Crate => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
262 hir::Visibility::Restricted { ref path, .. } => match path.def {
263 // If there is no resolution, `resolve` will have already reported an error, so
264 // assume that the visibility is public to avoid reporting more privacy errors.
265 Def::Err => Visibility::Public,
266 def => Visibility::Restricted(def.def_id()),
269 Visibility::Restricted(tcx.hir.local_def_id(tcx.hir.get_module_parent(id)))
274 /// Returns true if an item with this visibility is accessible from the given block.
275 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
276 let restriction = match self {
277 // Public items are visible everywhere.
278 Visibility::Public => return true,
279 // Private items from other crates are visible nowhere.
280 Visibility::Invisible => return false,
281 // Restricted items are visible in an arbitrary local module.
282 Visibility::Restricted(other) if other.krate != module.krate => return false,
283 Visibility::Restricted(module) => module,
286 tree.is_descendant_of(module, restriction)
289 /// Returns true if this visibility is at least as accessible as the given visibility
290 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
291 let vis_restriction = match vis {
292 Visibility::Public => return self == Visibility::Public,
293 Visibility::Invisible => return true,
294 Visibility::Restricted(module) => module,
297 self.is_accessible_from(vis_restriction, tree)
301 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
303 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
304 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
305 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
306 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
309 #[derive(Clone, Copy, Debug, RustcDecodable, RustcEncodable)]
310 pub struct MethodCallee<'tcx> {
311 /// Impl method ID, for inherent methods, or trait method ID, otherwise.
314 pub substs: &'tcx Substs<'tcx>
317 /// With method calls, we store some extra information in
318 /// side tables (i.e method_map). We use
319 /// MethodCall as a key to index into these tables instead of
320 /// just directly using the expression's NodeId. The reason
321 /// for this being that we may apply adjustments (coercions)
322 /// with the resulting expression also needing to use the
323 /// side tables. The problem with this is that we don't
324 /// assign a separate NodeId to this new expression
325 /// and so it would clash with the base expression if both
326 /// needed to add to the side tables. Thus to disambiguate
327 /// we also keep track of whether there's an adjustment in
329 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
330 pub struct MethodCall {
336 pub fn expr(id: NodeId) -> MethodCall {
343 pub fn autoderef(expr_id: NodeId, autoderef: u32) -> MethodCall {
346 autoderef: 1 + autoderef
351 // maps from an expression id that corresponds to a method call to the details
352 // of the method to be invoked
353 pub type MethodMap<'tcx> = FxHashMap<MethodCall, MethodCallee<'tcx>>;
355 // Contains information needed to resolve types and (in the future) look up
356 // the types of AST nodes.
357 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
358 pub struct CReaderCacheKey {
363 /// Describes the fragment-state associated with a NodeId.
365 /// Currently only unfragmented paths have entries in the table,
366 /// but longer-term this enum is expected to expand to also
367 /// include data for fragmented paths.
368 #[derive(Copy, Clone, Debug)]
369 pub enum FragmentInfo {
370 Moved { var: NodeId, move_expr: NodeId },
371 Assigned { var: NodeId, assign_expr: NodeId, assignee_id: NodeId },
374 // Flags that we track on types. These flags are propagated upwards
375 // through the type during type construction, so that we can quickly
376 // check whether the type has various kinds of types in it without
377 // recursing over the type itself.
379 flags TypeFlags: u32 {
380 const HAS_PARAMS = 1 << 0,
381 const HAS_SELF = 1 << 1,
382 const HAS_TY_INFER = 1 << 2,
383 const HAS_RE_INFER = 1 << 3,
384 const HAS_RE_SKOL = 1 << 4,
385 const HAS_RE_EARLY_BOUND = 1 << 5,
386 const HAS_FREE_REGIONS = 1 << 6,
387 const HAS_TY_ERR = 1 << 7,
388 const HAS_PROJECTION = 1 << 8,
389 const HAS_TY_CLOSURE = 1 << 9,
391 // true if there are "names" of types and regions and so forth
392 // that are local to a particular fn
393 const HAS_LOCAL_NAMES = 1 << 10,
395 // Present if the type belongs in a local type context.
396 // Only set for TyInfer other than Fresh.
397 const KEEP_IN_LOCAL_TCX = 1 << 11,
399 // Is there a projection that does not involve a bound region?
400 // Currently we can't normalize projections w/ bound regions.
401 const HAS_NORMALIZABLE_PROJECTION = 1 << 12,
403 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
404 TypeFlags::HAS_SELF.bits |
405 TypeFlags::HAS_RE_EARLY_BOUND.bits,
407 // Flags representing the nominal content of a type,
408 // computed by FlagsComputation. If you add a new nominal
409 // flag, it should be added here too.
410 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
411 TypeFlags::HAS_SELF.bits |
412 TypeFlags::HAS_TY_INFER.bits |
413 TypeFlags::HAS_RE_INFER.bits |
414 TypeFlags::HAS_RE_SKOL.bits |
415 TypeFlags::HAS_RE_EARLY_BOUND.bits |
416 TypeFlags::HAS_FREE_REGIONS.bits |
417 TypeFlags::HAS_TY_ERR.bits |
418 TypeFlags::HAS_PROJECTION.bits |
419 TypeFlags::HAS_TY_CLOSURE.bits |
420 TypeFlags::HAS_LOCAL_NAMES.bits |
421 TypeFlags::KEEP_IN_LOCAL_TCX.bits,
423 // Caches for type_is_sized, type_moves_by_default
424 const SIZEDNESS_CACHED = 1 << 16,
425 const IS_SIZED = 1 << 17,
426 const MOVENESS_CACHED = 1 << 18,
427 const MOVES_BY_DEFAULT = 1 << 19,
431 pub struct TyS<'tcx> {
432 pub sty: TypeVariants<'tcx>,
433 pub flags: Cell<TypeFlags>,
435 // the maximal depth of any bound regions appearing in this type.
439 impl<'tcx> PartialEq for TyS<'tcx> {
441 fn eq(&self, other: &TyS<'tcx>) -> bool {
442 // (self as *const _) == (other as *const _)
443 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
446 impl<'tcx> Eq for TyS<'tcx> {}
448 impl<'tcx> Hash for TyS<'tcx> {
449 fn hash<H: Hasher>(&self, s: &mut H) {
450 (self as *const TyS).hash(s)
454 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for ty::TyS<'tcx> {
455 fn hash_stable<W: StableHasherResult>(&self,
456 hcx: &mut StableHashingContext<'a, 'tcx>,
457 hasher: &mut StableHasher<W>) {
461 // The other fields just provide fast access to information that is
462 // also contained in `sty`, so no need to hash them.
467 sty.hash_stable(hcx, hasher);
471 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
473 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
474 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
476 /// A wrapper for slices with the additional invariant
477 /// that the slice is interned and no other slice with
478 /// the same contents can exist in the same context.
479 /// This means we can use pointer + length for both
480 /// equality comparisons and hashing.
481 #[derive(Debug, RustcEncodable)]
482 pub struct Slice<T>([T]);
484 impl<T> PartialEq for Slice<T> {
486 fn eq(&self, other: &Slice<T>) -> bool {
487 (&self.0 as *const [T]) == (&other.0 as *const [T])
490 impl<T> Eq for Slice<T> {}
492 impl<T> Hash for Slice<T> {
493 fn hash<H: Hasher>(&self, s: &mut H) {
494 (self.as_ptr(), self.len()).hash(s)
498 impl<T> Deref for Slice<T> {
500 fn deref(&self) -> &[T] {
505 impl<'a, T> IntoIterator for &'a Slice<T> {
507 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
508 fn into_iter(self) -> Self::IntoIter {
513 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {}
516 pub fn empty<'a>() -> &'a Slice<T> {
518 mem::transmute(slice::from_raw_parts(0x1 as *const T, 0))
523 /// Upvars do not get their own node-id. Instead, we use the pair of
524 /// the original var id (that is, the root variable that is referenced
525 /// by the upvar) and the id of the closure expression.
526 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
529 pub closure_expr_id: NodeId,
532 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
533 pub enum BorrowKind {
534 /// Data must be immutable and is aliasable.
537 /// Data must be immutable but not aliasable. This kind of borrow
538 /// cannot currently be expressed by the user and is used only in
539 /// implicit closure bindings. It is needed when the closure
540 /// is borrowing or mutating a mutable referent, e.g.:
542 /// let x: &mut isize = ...;
543 /// let y = || *x += 5;
545 /// If we were to try to translate this closure into a more explicit
546 /// form, we'd encounter an error with the code as written:
548 /// struct Env { x: & &mut isize }
549 /// let x: &mut isize = ...;
550 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
551 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
553 /// This is then illegal because you cannot mutate a `&mut` found
554 /// in an aliasable location. To solve, you'd have to translate with
555 /// an `&mut` borrow:
557 /// struct Env { x: & &mut isize }
558 /// let x: &mut isize = ...;
559 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
560 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
562 /// Now the assignment to `**env.x` is legal, but creating a
563 /// mutable pointer to `x` is not because `x` is not mutable. We
564 /// could fix this by declaring `x` as `let mut x`. This is ok in
565 /// user code, if awkward, but extra weird for closures, since the
566 /// borrow is hidden.
568 /// So we introduce a "unique imm" borrow -- the referent is
569 /// immutable, but not aliasable. This solves the problem. For
570 /// simplicity, we don't give users the way to express this
571 /// borrow, it's just used when translating closures.
574 /// Data is mutable and not aliasable.
578 /// Information describing the capture of an upvar. This is computed
579 /// during `typeck`, specifically by `regionck`.
580 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
581 pub enum UpvarCapture<'tcx> {
582 /// Upvar is captured by value. This is always true when the
583 /// closure is labeled `move`, but can also be true in other cases
584 /// depending on inference.
587 /// Upvar is captured by reference.
588 ByRef(UpvarBorrow<'tcx>),
591 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
592 pub struct UpvarBorrow<'tcx> {
593 /// The kind of borrow: by-ref upvars have access to shared
594 /// immutable borrows, which are not part of the normal language
596 pub kind: BorrowKind,
598 /// Region of the resulting reference.
599 pub region: &'tcx ty::Region,
602 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
604 #[derive(Copy, Clone)]
605 pub struct ClosureUpvar<'tcx> {
611 #[derive(Clone, Copy, PartialEq)]
612 pub enum IntVarValue {
614 UintType(ast::UintTy),
617 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
618 pub struct TypeParameterDef {
622 pub has_default: bool,
623 pub object_lifetime_default: ObjectLifetimeDefault,
625 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
626 /// on generic parameter `T`, asserts data behind the parameter
627 /// `T` won't be accessed during the parent type's `Drop` impl.
628 pub pure_wrt_drop: bool,
631 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
632 pub struct RegionParameterDef {
636 pub issue_32330: Option<ty::Issue32330>,
638 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
639 /// on generic parameter `'a`, asserts data of lifetime `'a`
640 /// won't be accessed during the parent type's `Drop` impl.
641 pub pure_wrt_drop: bool,
644 impl RegionParameterDef {
645 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
646 ty::EarlyBoundRegion {
652 pub fn to_bound_region(&self) -> ty::BoundRegion {
653 ty::BoundRegion::BrNamed(self.def_id, self.name)
657 /// Information about the formal type/lifetime parameters associated
658 /// with an item or method. Analogous to hir::Generics.
659 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
660 pub struct Generics {
661 pub parent: Option<DefId>,
662 pub parent_regions: u32,
663 pub parent_types: u32,
664 pub regions: Vec<RegionParameterDef>,
665 pub types: Vec<TypeParameterDef>,
667 /// Reverse map to each `TypeParameterDef`'s `index` field, from
668 /// `def_id.index` (`def_id.krate` is the same as the item's).
669 pub type_param_to_index: BTreeMap<DefIndex, u32>,
675 pub fn parent_count(&self) -> usize {
676 self.parent_regions as usize + self.parent_types as usize
679 pub fn own_count(&self) -> usize {
680 self.regions.len() + self.types.len()
683 pub fn count(&self) -> usize {
684 self.parent_count() + self.own_count()
687 pub fn region_param(&self, param: &EarlyBoundRegion) -> &RegionParameterDef {
688 assert_eq!(self.parent_count(), 0);
689 &self.regions[param.index as usize - self.has_self as usize]
692 pub fn type_param(&self, param: &ParamTy) -> &TypeParameterDef {
693 assert_eq!(self.parent_count(), 0);
694 &self.types[param.idx as usize - self.has_self as usize - self.regions.len()]
698 /// Bounds on generics.
699 #[derive(Clone, Default)]
700 pub struct GenericPredicates<'tcx> {
701 pub parent: Option<DefId>,
702 pub predicates: Vec<Predicate<'tcx>>,
705 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
706 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
708 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
709 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
710 -> InstantiatedPredicates<'tcx> {
711 let mut instantiated = InstantiatedPredicates::empty();
712 self.instantiate_into(tcx, &mut instantiated, substs);
715 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
716 -> InstantiatedPredicates<'tcx> {
717 InstantiatedPredicates {
718 predicates: self.predicates.subst(tcx, substs)
722 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
723 instantiated: &mut InstantiatedPredicates<'tcx>,
724 substs: &Substs<'tcx>) {
725 if let Some(def_id) = self.parent {
726 tcx.item_predicates(def_id).instantiate_into(tcx, instantiated, substs);
728 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
731 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
732 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
733 -> InstantiatedPredicates<'tcx>
735 assert_eq!(self.parent, None);
736 InstantiatedPredicates {
737 predicates: self.predicates.iter().map(|pred| {
738 pred.subst_supertrait(tcx, poly_trait_ref)
744 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
745 pub enum Predicate<'tcx> {
746 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
747 /// the `Self` type of the trait reference and `A`, `B`, and `C`
748 /// would be the type parameters.
749 Trait(PolyTraitPredicate<'tcx>),
751 /// where `T1 == T2`.
752 Equate(PolyEquatePredicate<'tcx>),
755 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
758 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
760 /// where <T as TraitRef>::Name == X, approximately.
761 /// See `ProjectionPredicate` struct for details.
762 Projection(PolyProjectionPredicate<'tcx>),
765 WellFormed(Ty<'tcx>),
767 /// trait must be object-safe
770 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
771 /// for some substitutions `...` and T being a closure type.
772 /// Satisfied (or refuted) once we know the closure's kind.
773 ClosureKind(DefId, ClosureKind),
776 Subtype(PolySubtypePredicate<'tcx>),
779 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
780 /// Performs a substitution suitable for going from a
781 /// poly-trait-ref to supertraits that must hold if that
782 /// poly-trait-ref holds. This is slightly different from a normal
783 /// substitution in terms of what happens with bound regions. See
784 /// lengthy comment below for details.
785 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
786 trait_ref: &ty::PolyTraitRef<'tcx>)
787 -> ty::Predicate<'tcx>
789 // The interaction between HRTB and supertraits is not entirely
790 // obvious. Let me walk you (and myself) through an example.
792 // Let's start with an easy case. Consider two traits:
794 // trait Foo<'a> : Bar<'a,'a> { }
795 // trait Bar<'b,'c> { }
797 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
798 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
799 // knew that `Foo<'x>` (for any 'x) then we also know that
800 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
801 // normal substitution.
803 // In terms of why this is sound, the idea is that whenever there
804 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
805 // holds. So if there is an impl of `T:Foo<'a>` that applies to
806 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
809 // Another example to be careful of is this:
811 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
812 // trait Bar1<'b,'c> { }
814 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
815 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
816 // reason is similar to the previous example: any impl of
817 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
818 // basically we would want to collapse the bound lifetimes from
819 // the input (`trait_ref`) and the supertraits.
821 // To achieve this in practice is fairly straightforward. Let's
822 // consider the more complicated scenario:
824 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
825 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
826 // where both `'x` and `'b` would have a DB index of 1.
827 // The substitution from the input trait-ref is therefore going to be
828 // `'a => 'x` (where `'x` has a DB index of 1).
829 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
830 // early-bound parameter and `'b' is a late-bound parameter with a
832 // - If we replace `'a` with `'x` from the input, it too will have
833 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
834 // just as we wanted.
836 // There is only one catch. If we just apply the substitution `'a
837 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
838 // adjust the DB index because we substituting into a binder (it
839 // tries to be so smart...) resulting in `for<'x> for<'b>
840 // Bar1<'x,'b>` (we have no syntax for this, so use your
841 // imagination). Basically the 'x will have DB index of 2 and 'b
842 // will have DB index of 1. Not quite what we want. So we apply
843 // the substitution to the *contents* of the trait reference,
844 // rather than the trait reference itself (put another way, the
845 // substitution code expects equal binding levels in the values
846 // from the substitution and the value being substituted into, and
847 // this trick achieves that).
849 let substs = &trait_ref.0.substs;
851 Predicate::Trait(ty::Binder(ref data)) =>
852 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
853 Predicate::Equate(ty::Binder(ref data)) =>
854 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
855 Predicate::Subtype(ty::Binder(ref data)) =>
856 Predicate::Subtype(ty::Binder(data.subst(tcx, substs))),
857 Predicate::RegionOutlives(ty::Binder(ref data)) =>
858 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
859 Predicate::TypeOutlives(ty::Binder(ref data)) =>
860 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
861 Predicate::Projection(ty::Binder(ref data)) =>
862 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
863 Predicate::WellFormed(data) =>
864 Predicate::WellFormed(data.subst(tcx, substs)),
865 Predicate::ObjectSafe(trait_def_id) =>
866 Predicate::ObjectSafe(trait_def_id),
867 Predicate::ClosureKind(closure_def_id, kind) =>
868 Predicate::ClosureKind(closure_def_id, kind),
873 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
874 pub struct TraitPredicate<'tcx> {
875 pub trait_ref: TraitRef<'tcx>
877 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
879 impl<'tcx> TraitPredicate<'tcx> {
880 pub fn def_id(&self) -> DefId {
881 self.trait_ref.def_id
884 /// Creates the dep-node for selecting/evaluating this trait reference.
885 fn dep_node(&self) -> DepNode<DefId> {
886 // Extact the trait-def and first def-id from inputs. See the
887 // docs for `DepNode::TraitSelect` for more information.
888 let trait_def_id = self.def_id();
891 .flat_map(|t| t.walk())
892 .filter_map(|t| match t.sty {
893 ty::TyAdt(adt_def, _) => Some(adt_def.did),
897 .unwrap_or(trait_def_id);
898 DepNode::TraitSelect {
899 trait_def_id: trait_def_id,
900 input_def_id: input_def_id
904 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
905 self.trait_ref.input_types()
908 pub fn self_ty(&self) -> Ty<'tcx> {
909 self.trait_ref.self_ty()
913 impl<'tcx> PolyTraitPredicate<'tcx> {
914 pub fn def_id(&self) -> DefId {
915 // ok to skip binder since trait def-id does not care about regions
919 pub fn dep_node(&self) -> DepNode<DefId> {
920 // ok to skip binder since depnode does not care about regions
925 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
926 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
927 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
929 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
930 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
931 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
932 pub type PolyRegionOutlivesPredicate<'tcx> = PolyOutlivesPredicate<&'tcx ty::Region,
934 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, &'tcx ty::Region>;
936 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
937 pub struct SubtypePredicate<'tcx> {
938 pub a_is_expected: bool,
942 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
944 /// This kind of predicate has no *direct* correspondent in the
945 /// syntax, but it roughly corresponds to the syntactic forms:
947 /// 1. `T : TraitRef<..., Item=Type>`
948 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
950 /// In particular, form #1 is "desugared" to the combination of a
951 /// normal trait predicate (`T : TraitRef<...>`) and one of these
952 /// predicates. Form #2 is a broader form in that it also permits
953 /// equality between arbitrary types. Processing an instance of Form
954 /// #2 eventually yields one of these `ProjectionPredicate`
955 /// instances to normalize the LHS.
956 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
957 pub struct ProjectionPredicate<'tcx> {
958 pub projection_ty: ProjectionTy<'tcx>,
962 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
964 impl<'tcx> PolyProjectionPredicate<'tcx> {
965 pub fn item_name(&self) -> Name {
966 self.0.projection_ty.item_name // safe to skip the binder to access a name
970 pub trait ToPolyTraitRef<'tcx> {
971 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
974 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
975 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
976 assert!(!self.has_escaping_regions());
977 ty::Binder(self.clone())
981 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
982 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
983 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
987 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
988 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
989 // Note: unlike with TraitRef::to_poly_trait_ref(),
990 // self.0.trait_ref is permitted to have escaping regions.
991 // This is because here `self` has a `Binder` and so does our
992 // return value, so we are preserving the number of binding
994 ty::Binder(self.0.projection_ty.trait_ref)
998 pub trait ToPredicate<'tcx> {
999 fn to_predicate(&self) -> Predicate<'tcx>;
1002 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1003 fn to_predicate(&self) -> Predicate<'tcx> {
1004 // we're about to add a binder, so let's check that we don't
1005 // accidentally capture anything, or else that might be some
1006 // weird debruijn accounting.
1007 assert!(!self.has_escaping_regions());
1009 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
1010 trait_ref: self.clone()
1015 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1016 fn to_predicate(&self) -> Predicate<'tcx> {
1017 ty::Predicate::Trait(self.to_poly_trait_predicate())
1021 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
1022 fn to_predicate(&self) -> Predicate<'tcx> {
1023 Predicate::Equate(self.clone())
1027 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1028 fn to_predicate(&self) -> Predicate<'tcx> {
1029 Predicate::RegionOutlives(self.clone())
1033 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1034 fn to_predicate(&self) -> Predicate<'tcx> {
1035 Predicate::TypeOutlives(self.clone())
1039 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1040 fn to_predicate(&self) -> Predicate<'tcx> {
1041 Predicate::Projection(self.clone())
1045 impl<'tcx> Predicate<'tcx> {
1046 /// Iterates over the types in this predicate. Note that in all
1047 /// cases this is skipping over a binder, so late-bound regions
1048 /// with depth 0 are bound by the predicate.
1049 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1050 let vec: Vec<_> = match *self {
1051 ty::Predicate::Trait(ref data) => {
1052 data.skip_binder().input_types().collect()
1054 ty::Predicate::Equate(ty::Binder(ref data)) => {
1055 vec![data.0, data.1]
1057 ty::Predicate::Subtype(ty::Binder(SubtypePredicate { a, b, a_is_expected: _ })) => {
1060 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
1063 ty::Predicate::RegionOutlives(..) => {
1066 ty::Predicate::Projection(ref data) => {
1067 let trait_inputs = data.0.projection_ty.trait_ref.input_types();
1068 trait_inputs.chain(Some(data.0.ty)).collect()
1070 ty::Predicate::WellFormed(data) => {
1073 ty::Predicate::ObjectSafe(_trait_def_id) => {
1076 ty::Predicate::ClosureKind(_closure_def_id, _kind) => {
1081 // The only reason to collect into a vector here is that I was
1082 // too lazy to make the full (somewhat complicated) iterator
1083 // type that would be needed here. But I wanted this fn to
1084 // return an iterator conceptually, rather than a `Vec`, so as
1085 // to be closer to `Ty::walk`.
1089 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1091 Predicate::Trait(ref t) => {
1092 Some(t.to_poly_trait_ref())
1094 Predicate::Projection(..) |
1095 Predicate::Equate(..) |
1096 Predicate::Subtype(..) |
1097 Predicate::RegionOutlives(..) |
1098 Predicate::WellFormed(..) |
1099 Predicate::ObjectSafe(..) |
1100 Predicate::ClosureKind(..) |
1101 Predicate::TypeOutlives(..) => {
1108 /// Represents the bounds declared on a particular set of type
1109 /// parameters. Should eventually be generalized into a flag list of
1110 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1111 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1112 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1113 /// the `GenericPredicates` are expressed in terms of the bound type
1114 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1115 /// represented a set of bounds for some particular instantiation,
1116 /// meaning that the generic parameters have been substituted with
1121 /// struct Foo<T,U:Bar<T>> { ... }
1123 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1124 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1125 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1126 /// [usize:Bar<isize>]]`.
1128 pub struct InstantiatedPredicates<'tcx> {
1129 pub predicates: Vec<Predicate<'tcx>>,
1132 impl<'tcx> InstantiatedPredicates<'tcx> {
1133 pub fn empty() -> InstantiatedPredicates<'tcx> {
1134 InstantiatedPredicates { predicates: vec![] }
1137 pub fn is_empty(&self) -> bool {
1138 self.predicates.is_empty()
1142 /// When type checking, we use the `ParameterEnvironment` to track
1143 /// details about the type/lifetime parameters that are in scope.
1144 /// It primarily stores the bounds information.
1146 /// Note: This information might seem to be redundant with the data in
1147 /// `tcx.ty_param_defs`, but it is not. That table contains the
1148 /// parameter definitions from an "outside" perspective, but this
1149 /// struct will contain the bounds for a parameter as seen from inside
1150 /// the function body. Currently the only real distinction is that
1151 /// bound lifetime parameters are replaced with free ones, but in the
1152 /// future I hope to refine the representation of types so as to make
1153 /// more distinctions clearer.
1155 pub struct ParameterEnvironment<'tcx> {
1156 /// See `construct_free_substs` for details.
1157 pub free_substs: &'tcx Substs<'tcx>,
1159 /// Each type parameter has an implicit region bound that
1160 /// indicates it must outlive at least the function body (the user
1161 /// may specify stronger requirements). This field indicates the
1162 /// region of the callee.
1163 pub implicit_region_bound: &'tcx ty::Region,
1165 /// Obligations that the caller must satisfy. This is basically
1166 /// the set of bounds on the in-scope type parameters, translated
1167 /// into Obligations, and elaborated and normalized.
1168 pub caller_bounds: Vec<ty::Predicate<'tcx>>,
1170 /// Scope that is attached to free regions for this scope. This
1171 /// is usually the id of the fn body, but for more abstract scopes
1172 /// like structs we often use the node-id of the struct.
1174 /// FIXME(#3696). It would be nice to refactor so that free
1175 /// regions don't have this implicit scope and instead introduce
1176 /// relationships in the environment.
1177 pub free_id_outlive: CodeExtent,
1179 /// A cache for `moves_by_default`.
1180 pub is_copy_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1182 /// A cache for `type_is_sized`
1183 pub is_sized_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1186 impl<'a, 'tcx> ParameterEnvironment<'tcx> {
1187 pub fn with_caller_bounds(&self,
1188 caller_bounds: Vec<ty::Predicate<'tcx>>)
1189 -> ParameterEnvironment<'tcx>
1191 ParameterEnvironment {
1192 free_substs: self.free_substs,
1193 implicit_region_bound: self.implicit_region_bound,
1194 caller_bounds: caller_bounds,
1195 free_id_outlive: self.free_id_outlive,
1196 is_copy_cache: RefCell::new(FxHashMap()),
1197 is_sized_cache: RefCell::new(FxHashMap()),
1201 /// Construct a parameter environment given an item, impl item, or trait item
1202 pub fn for_item(tcx: TyCtxt<'a, 'tcx, 'tcx>, id: NodeId)
1203 -> ParameterEnvironment<'tcx> {
1204 match tcx.hir.find(id) {
1205 Some(hir_map::NodeImplItem(ref impl_item)) => {
1206 match impl_item.node {
1207 hir::ImplItemKind::Type(_) | hir::ImplItemKind::Const(..) => {
1208 // associated types don't have their own entry (for some reason),
1209 // so for now just grab environment for the impl
1210 let impl_id = tcx.hir.get_parent(id);
1211 let impl_def_id = tcx.hir.local_def_id(impl_id);
1212 tcx.construct_parameter_environment(impl_item.span,
1214 tcx.region_maps.item_extent(id))
1216 hir::ImplItemKind::Method(_, ref body) => {
1217 tcx.construct_parameter_environment(
1219 tcx.hir.local_def_id(id),
1220 tcx.region_maps.call_site_extent(id, body.node_id))
1224 Some(hir_map::NodeTraitItem(trait_item)) => {
1225 match trait_item.node {
1226 hir::TraitItemKind::Type(..) | hir::TraitItemKind::Const(..) => {
1227 // associated types don't have their own entry (for some reason),
1228 // so for now just grab environment for the trait
1229 let trait_id = tcx.hir.get_parent(id);
1230 let trait_def_id = tcx.hir.local_def_id(trait_id);
1231 tcx.construct_parameter_environment(trait_item.span,
1233 tcx.region_maps.item_extent(id))
1235 hir::TraitItemKind::Method(_, ref body) => {
1236 // Use call-site for extent (unless this is a
1237 // trait method with no default; then fallback
1238 // to the method id).
1239 let extent = if let hir::TraitMethod::Provided(body_id) = *body {
1240 // default impl: use call_site extent as free_id_outlive bound.
1241 tcx.region_maps.call_site_extent(id, body_id.node_id)
1243 // no default impl: use item extent as free_id_outlive bound.
1244 tcx.region_maps.item_extent(id)
1246 tcx.construct_parameter_environment(
1248 tcx.hir.local_def_id(id),
1253 Some(hir_map::NodeItem(item)) => {
1255 hir::ItemFn(.., body_id) => {
1256 // We assume this is a function.
1257 let fn_def_id = tcx.hir.local_def_id(id);
1259 tcx.construct_parameter_environment(
1262 tcx.region_maps.call_site_extent(id, body_id.node_id))
1265 hir::ItemStruct(..) |
1266 hir::ItemUnion(..) |
1269 hir::ItemConst(..) |
1270 hir::ItemStatic(..) => {
1271 let def_id = tcx.hir.local_def_id(id);
1272 tcx.construct_parameter_environment(item.span,
1274 tcx.region_maps.item_extent(id))
1276 hir::ItemTrait(..) => {
1277 let def_id = tcx.hir.local_def_id(id);
1278 tcx.construct_parameter_environment(item.span,
1280 tcx.region_maps.item_extent(id))
1283 span_bug!(item.span,
1284 "ParameterEnvironment::for_item():
1285 can't create a parameter \
1286 environment for this kind of item")
1290 Some(hir_map::NodeExpr(expr)) => {
1291 // This is a convenience to allow closures to work.
1292 if let hir::ExprClosure(.., body, _) = expr.node {
1293 let def_id = tcx.hir.local_def_id(id);
1294 let base_def_id = tcx.closure_base_def_id(def_id);
1295 tcx.construct_parameter_environment(
1298 tcx.region_maps.call_site_extent(id, body.node_id))
1300 tcx.empty_parameter_environment()
1303 Some(hir_map::NodeForeignItem(item)) => {
1304 let def_id = tcx.hir.local_def_id(id);
1305 tcx.construct_parameter_environment(item.span,
1309 Some(hir_map::NodeStructCtor(..)) |
1310 Some(hir_map::NodeVariant(..)) => {
1311 let def_id = tcx.hir.local_def_id(id);
1312 tcx.construct_parameter_environment(tcx.hir.span(id),
1317 bug!("ParameterEnvironment::from_item(): \
1318 `{}` = {:?} is unsupported",
1319 tcx.hir.node_to_string(id), it)
1325 #[derive(Copy, Clone, Debug)]
1326 pub struct Destructor {
1327 /// The def-id of the destructor method
1329 /// Invoking the destructor of a dtorck type during usual cleanup
1330 /// (e.g. the glue emitted for stack unwinding) requires all
1331 /// lifetimes in the type-structure of `adt` to strictly outlive
1332 /// the adt value itself.
1334 /// If `adt` is not dtorck, then the adt's destructor can be
1335 /// invoked even when there are lifetimes in the type-structure of
1336 /// `adt` that do not strictly outlive the adt value itself.
1337 /// (This allows programs to make cyclic structures without
1338 /// resorting to unsafe means; see RFCs 769 and 1238).
1339 pub is_dtorck: bool,
1343 flags AdtFlags: u32 {
1344 const NO_ADT_FLAGS = 0,
1345 const IS_ENUM = 1 << 0,
1346 const IS_PHANTOM_DATA = 1 << 1,
1347 const IS_FUNDAMENTAL = 1 << 2,
1348 const IS_UNION = 1 << 3,
1349 const IS_BOX = 1 << 4,
1354 pub struct VariantDef {
1355 /// The variant's DefId. If this is a tuple-like struct,
1356 /// this is the DefId of the struct's ctor.
1358 pub name: Name, // struct's name if this is a struct
1359 pub discr: VariantDiscr,
1360 pub fields: Vec<FieldDef>,
1361 pub ctor_kind: CtorKind,
1364 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1365 pub enum VariantDiscr {
1366 /// Explicit value for this variant, i.e. `X = 123`.
1367 /// The `DefId` corresponds to the embedded constant.
1370 /// The previous variant's discriminant plus one.
1371 /// For efficiency reasons, the distance from the
1372 /// last `Explicit` discriminant is being stored,
1373 /// or `0` for the first variant, if it has none.
1378 pub struct FieldDef {
1381 pub vis: Visibility,
1384 /// The definition of an abstract data type - a struct or enum.
1386 /// These are all interned (by intern_adt_def) into the adt_defs
1390 pub variants: Vec<VariantDef>,
1392 pub repr: ReprOptions,
1395 impl PartialEq for AdtDef {
1396 // AdtDef are always interned and this is part of TyS equality
1398 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1401 impl Eq for AdtDef {}
1403 impl Hash for AdtDef {
1405 fn hash<H: Hasher>(&self, s: &mut H) {
1406 (self as *const AdtDef).hash(s)
1410 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1411 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1416 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1419 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for AdtDef {
1420 fn hash_stable<W: StableHasherResult>(&self,
1421 hcx: &mut StableHashingContext<'a, 'tcx>,
1422 hasher: &mut StableHasher<W>) {
1430 did.hash_stable(hcx, hasher);
1431 variants.hash_stable(hcx, hasher);
1432 flags.hash_stable(hcx, hasher);
1433 repr.hash_stable(hcx, hasher);
1437 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1438 pub enum AdtKind { Struct, Union, Enum }
1441 #[derive(RustcEncodable, RustcDecodable, Default)]
1442 flags ReprFlags: u8 {
1443 const IS_C = 1 << 0,
1444 const IS_PACKED = 1 << 1,
1445 const IS_SIMD = 1 << 2,
1446 // Internal only for now. If true, don't reorder fields.
1447 const IS_LINEAR = 1 << 3,
1449 // Any of these flags being set prevent field reordering optimisation.
1450 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1451 ReprFlags::IS_PACKED.bits |
1452 ReprFlags::IS_SIMD.bits |
1453 ReprFlags::IS_LINEAR.bits,
1457 impl_stable_hash_for!(struct ReprFlags {
1463 /// Represents the repr options provided by the user,
1464 #[derive(Copy, Clone, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1465 pub struct ReprOptions {
1466 pub int: Option<attr::IntType>,
1467 pub flags: ReprFlags,
1470 impl_stable_hash_for!(struct ReprOptions {
1476 pub fn new(tcx: TyCtxt, did: DefId) -> ReprOptions {
1477 let mut flags = ReprFlags::empty();
1478 let mut size = None;
1480 for attr in tcx.get_attrs(did).iter() {
1481 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1482 flags.insert(match r {
1483 attr::ReprExtern => ReprFlags::IS_C,
1484 attr::ReprPacked => ReprFlags::IS_PACKED,
1485 attr::ReprSimd => ReprFlags::IS_SIMD,
1486 attr::ReprInt(i) => {
1494 // FIXME(eddyb) This is deprecated and should be removed.
1495 if tcx.has_attr(did, "simd") {
1496 flags.insert(ReprFlags::IS_SIMD);
1499 // This is here instead of layout because the choice must make it into metadata.
1500 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1501 flags.insert(ReprFlags::IS_LINEAR);
1503 ReprOptions { int: size, flags: flags }
1507 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1509 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1511 pub fn packed(&self) -> bool { self.flags.contains(ReprFlags::IS_PACKED) }
1513 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1515 pub fn discr_type(&self) -> attr::IntType {
1516 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Is))
1519 /// Returns true if this `#[repr()]` should inhabit "smart enum
1520 /// layout" optimizations, such as representing `Foo<&T>` as a
1522 pub fn inhibit_enum_layout_opt(&self) -> bool {
1523 self.c() || self.int.is_some()
1527 impl<'a, 'gcx, 'tcx> AdtDef {
1531 variants: Vec<VariantDef>,
1532 repr: ReprOptions) -> Self {
1533 let mut flags = AdtFlags::NO_ADT_FLAGS;
1534 let attrs = tcx.get_attrs(did);
1535 if attr::contains_name(&attrs, "fundamental") {
1536 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1538 if Some(did) == tcx.lang_items.phantom_data() {
1539 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1541 if Some(did) == tcx.lang_items.owned_box() {
1542 flags = flags | AdtFlags::IS_BOX;
1545 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
1546 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
1547 AdtKind::Struct => {}
1558 pub fn is_struct(&self) -> bool {
1559 !self.is_union() && !self.is_enum()
1563 pub fn is_union(&self) -> bool {
1564 self.flags.intersects(AdtFlags::IS_UNION)
1568 pub fn is_enum(&self) -> bool {
1569 self.flags.intersects(AdtFlags::IS_ENUM)
1572 /// Returns the kind of the ADT - Struct or Enum.
1574 pub fn adt_kind(&self) -> AdtKind {
1577 } else if self.is_union() {
1584 pub fn descr(&self) -> &'static str {
1585 match self.adt_kind() {
1586 AdtKind::Struct => "struct",
1587 AdtKind::Union => "union",
1588 AdtKind::Enum => "enum",
1592 pub fn variant_descr(&self) -> &'static str {
1593 match self.adt_kind() {
1594 AdtKind::Struct => "struct",
1595 AdtKind::Union => "union",
1596 AdtKind::Enum => "variant",
1600 /// Returns whether this is a dtorck type. If this returns
1601 /// true, this type being safe for destruction requires it to be
1602 /// alive; Otherwise, only the contents are required to be.
1604 pub fn is_dtorck(&'gcx self, tcx: TyCtxt) -> bool {
1605 self.destructor(tcx).map_or(false, |d| d.is_dtorck)
1608 /// Returns whether this type is #[fundamental] for the purposes
1609 /// of coherence checking.
1611 pub fn is_fundamental(&self) -> bool {
1612 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
1615 /// Returns true if this is PhantomData<T>.
1617 pub fn is_phantom_data(&self) -> bool {
1618 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
1621 /// Returns true if this is Box<T>.
1623 pub fn is_box(&self) -> bool {
1624 self.flags.intersects(AdtFlags::IS_BOX)
1627 /// Returns whether this type has a destructor.
1628 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
1629 self.destructor(tcx).is_some()
1632 /// Asserts this is a struct and returns the struct's unique
1634 pub fn struct_variant(&self) -> &VariantDef {
1635 assert!(!self.is_enum());
1640 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
1641 tcx.item_predicates(self.did)
1644 /// Returns an iterator over all fields contained
1647 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
1648 self.variants.iter().flat_map(|v| v.fields.iter())
1652 pub fn is_univariant(&self) -> bool {
1653 self.variants.len() == 1
1656 pub fn is_payloadfree(&self) -> bool {
1657 !self.variants.is_empty() &&
1658 self.variants.iter().all(|v| v.fields.is_empty())
1661 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
1664 .find(|v| v.did == vid)
1665 .expect("variant_with_id: unknown variant")
1668 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1671 .position(|v| v.did == vid)
1672 .expect("variant_index_with_id: unknown variant")
1675 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
1677 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
1678 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
1679 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.struct_variant(),
1680 _ => bug!("unexpected def {:?} in variant_of_def", def)
1684 pub fn discriminants(&'a self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1685 -> impl Iterator<Item=ConstInt> + 'a {
1686 let repr_type = self.repr.discr_type();
1687 let initial = repr_type.initial_discriminant(tcx.global_tcx());
1688 let mut prev_discr = None::<ConstInt>;
1689 self.variants.iter().map(move |v| {
1690 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr());
1691 if let VariantDiscr::Explicit(expr_did) = v.discr {
1692 match queries::monomorphic_const_eval::get(tcx, DUMMY_SP, expr_did) {
1693 Ok(ConstVal::Integral(v)) => {
1699 prev_discr = Some(discr);
1705 /// Compute the discriminant value used by a specific variant.
1706 /// Unlike `discriminants`, this is (amortized) constant-time,
1707 /// only doing at most one query for evaluating an explicit
1708 /// discriminant (the last one before the requested variant),
1709 /// assuming there are no constant-evaluation errors there.
1710 pub fn discriminant_for_variant(&self,
1711 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1712 variant_index: usize)
1714 let repr_type = self.repr.discr_type();
1715 let mut explicit_value = repr_type.initial_discriminant(tcx.global_tcx());
1716 let mut explicit_index = variant_index;
1718 match self.variants[explicit_index].discr {
1719 ty::VariantDiscr::Relative(0) => break,
1720 ty::VariantDiscr::Relative(distance) => {
1721 explicit_index -= distance;
1723 ty::VariantDiscr::Explicit(expr_did) => {
1724 match queries::monomorphic_const_eval::get(tcx, DUMMY_SP, expr_did) {
1725 Ok(ConstVal::Integral(v)) => {
1730 explicit_index -= 1;
1736 let discr = explicit_value.to_u128_unchecked()
1737 .wrapping_add((variant_index - explicit_index) as u128);
1739 attr::UnsignedInt(ty) => {
1740 ConstInt::new_unsigned_truncating(discr, ty,
1741 tcx.sess.target.uint_type)
1743 attr::SignedInt(ty) => {
1744 ConstInt::new_signed_truncating(discr as i128, ty,
1745 tcx.sess.target.int_type)
1750 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
1751 queries::adt_destructor::get(tcx, DUMMY_SP, self.did)
1754 /// Returns a simpler type such that `Self: Sized` if and only
1755 /// if that type is Sized, or `TyErr` if this type is recursive.
1757 /// HACK: instead of returning a list of types, this function can
1758 /// return a tuple. In that case, the result is Sized only if
1759 /// all elements of the tuple are Sized.
1761 /// This is generally the `struct_tail` if this is a struct, or a
1762 /// tuple of them if this is an enum.
1764 /// Oddly enough, checking that the sized-constraint is Sized is
1765 /// actually more expressive than checking all members:
1766 /// the Sized trait is inductive, so an associated type that references
1767 /// Self would prevent its containing ADT from being Sized.
1769 /// Due to normalization being eager, this applies even if
1770 /// the associated type is behind a pointer, e.g. issue #31299.
1771 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Ty<'tcx> {
1772 match queries::adt_sized_constraint::try_get(tcx, DUMMY_SP, self.did) {
1775 debug!("adt_sized_constraint: {:?} is recursive", self);
1776 // This should be reported as an error by `check_representable`.
1778 // Consider the type as Sized in the meanwhile to avoid
1785 fn sized_constraint_for_ty(&self,
1786 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1789 let result = match ty.sty {
1790 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
1791 TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
1792 TyArray(..) | TyClosure(..) | TyNever => {
1796 TyStr | TyDynamic(..) | TySlice(_) | TyError => {
1797 // these are never sized - return the target type
1801 TyTuple(ref tys, _) => {
1804 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
1808 TyAdt(adt, substs) => {
1811 adt.sized_constraint(tcx)
1812 .subst(tcx, substs);
1813 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
1815 if let ty::TyTuple(ref tys, _) = adt_ty.sty {
1816 tys.iter().flat_map(|ty| {
1817 self.sized_constraint_for_ty(tcx, ty)
1820 self.sized_constraint_for_ty(tcx, adt_ty)
1824 TyProjection(..) | TyAnon(..) => {
1825 // must calculate explicitly.
1826 // FIXME: consider special-casing always-Sized projections
1831 // perf hack: if there is a `T: Sized` bound, then
1832 // we know that `T` is Sized and do not need to check
1835 let sized_trait = match tcx.lang_items.sized_trait() {
1837 _ => return vec![ty]
1839 let sized_predicate = Binder(TraitRef {
1840 def_id: sized_trait,
1841 substs: tcx.mk_substs_trait(ty, &[])
1843 let predicates = tcx.item_predicates(self.did).predicates;
1844 if predicates.into_iter().any(|p| p == sized_predicate) {
1852 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
1856 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
1861 impl<'a, 'gcx, 'tcx> VariantDef {
1863 pub fn find_field_named(&self,
1865 -> Option<&FieldDef> {
1866 self.fields.iter().find(|f| f.name == name)
1870 pub fn index_of_field_named(&self,
1873 self.fields.iter().position(|f| f.name == name)
1877 pub fn field_named(&self, name: ast::Name) -> &FieldDef {
1878 self.find_field_named(name).unwrap()
1882 impl<'a, 'gcx, 'tcx> FieldDef {
1883 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1884 tcx.item_type(self.did).subst(tcx, subst)
1888 /// Records the substitutions used to translate the polytype for an
1889 /// item into the monotype of an item reference.
1890 #[derive(Clone, RustcEncodable, RustcDecodable)]
1891 pub struct ItemSubsts<'tcx> {
1892 pub substs: &'tcx Substs<'tcx>,
1895 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1896 pub enum ClosureKind {
1897 // Warning: Ordering is significant here! The ordering is chosen
1898 // because the trait Fn is a subtrait of FnMut and so in turn, and
1899 // hence we order it so that Fn < FnMut < FnOnce.
1905 impl<'a, 'tcx> ClosureKind {
1906 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
1908 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
1909 ClosureKind::FnMut => {
1910 tcx.require_lang_item(FnMutTraitLangItem)
1912 ClosureKind::FnOnce => {
1913 tcx.require_lang_item(FnOnceTraitLangItem)
1918 /// True if this a type that impls this closure kind
1919 /// must also implement `other`.
1920 pub fn extends(self, other: ty::ClosureKind) -> bool {
1921 match (self, other) {
1922 (ClosureKind::Fn, ClosureKind::Fn) => true,
1923 (ClosureKind::Fn, ClosureKind::FnMut) => true,
1924 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
1925 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
1926 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
1927 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
1933 impl<'tcx> TyS<'tcx> {
1934 /// Iterator that walks `self` and any types reachable from
1935 /// `self`, in depth-first order. Note that just walks the types
1936 /// that appear in `self`, it does not descend into the fields of
1937 /// structs or variants. For example:
1940 /// isize => { isize }
1941 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
1942 /// [isize] => { [isize], isize }
1944 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
1945 TypeWalker::new(self)
1948 /// Iterator that walks the immediate children of `self`. Hence
1949 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
1950 /// (but not `i32`, like `walk`).
1951 pub fn walk_shallow(&'tcx self) -> AccIntoIter<walk::TypeWalkerArray<'tcx>> {
1952 walk::walk_shallow(self)
1955 /// Walks `ty` and any types appearing within `ty`, invoking the
1956 /// callback `f` on each type. If the callback returns false, then the
1957 /// children of the current type are ignored.
1959 /// Note: prefer `ty.walk()` where possible.
1960 pub fn maybe_walk<F>(&'tcx self, mut f: F)
1961 where F : FnMut(Ty<'tcx>) -> bool
1963 let mut walker = self.walk();
1964 while let Some(ty) = walker.next() {
1966 walker.skip_current_subtree();
1972 impl<'tcx> ItemSubsts<'tcx> {
1973 pub fn is_noop(&self) -> bool {
1974 self.substs.is_noop()
1978 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1979 pub enum LvaluePreference {
1984 impl LvaluePreference {
1985 pub fn from_mutbl(m: hir::Mutability) -> Self {
1987 hir::MutMutable => PreferMutLvalue,
1988 hir::MutImmutable => NoPreference,
1994 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
1996 hir::MutMutable => MutBorrow,
1997 hir::MutImmutable => ImmBorrow,
2001 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2002 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2003 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2005 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2007 MutBorrow => hir::MutMutable,
2008 ImmBorrow => hir::MutImmutable,
2010 // We have no type corresponding to a unique imm borrow, so
2011 // use `&mut`. It gives all the capabilities of an `&uniq`
2012 // and hence is a safe "over approximation".
2013 UniqueImmBorrow => hir::MutMutable,
2017 pub fn to_user_str(&self) -> &'static str {
2019 MutBorrow => "mutable",
2020 ImmBorrow => "immutable",
2021 UniqueImmBorrow => "uniquely immutable",
2026 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2027 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2028 self.item_tables(self.hir.body_owner_def_id(body))
2031 pub fn item_tables(self, def_id: DefId) -> &'gcx TypeckTables<'gcx> {
2032 queries::typeck_tables::get(self, DUMMY_SP, def_id)
2035 pub fn expr_span(self, id: NodeId) -> Span {
2036 match self.hir.find(id) {
2037 Some(hir_map::NodeExpr(e)) => {
2041 bug!("Node id {} is not an expr: {:?}", id, f);
2044 bug!("Node id {} is not present in the node map", id);
2049 pub fn local_var_name_str(self, id: NodeId) -> InternedString {
2050 match self.hir.find(id) {
2051 Some(hir_map::NodeLocal(pat)) => {
2053 hir::PatKind::Binding(_, _, ref path1, _) => path1.node.as_str(),
2055 bug!("Variable id {} maps to {:?}, not local", id, pat);
2059 r => bug!("Variable id {} maps to {:?}, not local", id, r),
2063 pub fn expr_is_lval(self, expr: &hir::Expr) -> bool {
2065 hir::ExprPath(hir::QPath::Resolved(_, ref path)) => {
2067 Def::Local(..) | Def::Upvar(..) | Def::Static(..) | Def::Err => true,
2072 hir::ExprType(ref e, _) => {
2073 self.expr_is_lval(e)
2076 hir::ExprUnary(hir::UnDeref, _) |
2077 hir::ExprField(..) |
2078 hir::ExprTupField(..) |
2079 hir::ExprIndex(..) => {
2083 // Partially qualified paths in expressions can only legally
2084 // refer to associated items which are always rvalues.
2085 hir::ExprPath(hir::QPath::TypeRelative(..)) |
2088 hir::ExprMethodCall(..) |
2089 hir::ExprStruct(..) |
2092 hir::ExprMatch(..) |
2093 hir::ExprClosure(..) |
2094 hir::ExprBlock(..) |
2095 hir::ExprRepeat(..) |
2096 hir::ExprArray(..) |
2097 hir::ExprBreak(..) |
2098 hir::ExprAgain(..) |
2100 hir::ExprWhile(..) |
2102 hir::ExprAssign(..) |
2103 hir::ExprInlineAsm(..) |
2104 hir::ExprAssignOp(..) |
2106 hir::ExprUnary(..) |
2108 hir::ExprAddrOf(..) |
2109 hir::ExprBinary(..) |
2110 hir::ExprCast(..) => {
2116 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2117 self.associated_items(id)
2118 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2122 pub fn trait_impl_polarity(self, id: DefId) -> hir::ImplPolarity {
2123 if let Some(id) = self.hir.as_local_node_id(id) {
2124 match self.hir.expect_item(id).node {
2125 hir::ItemImpl(_, polarity, ..) => polarity,
2126 ref item => bug!("trait_impl_polarity: {:?} not an impl", item)
2129 self.sess.cstore.impl_polarity(id)
2133 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2134 self.associated_items(did).any(|item| {
2135 item.relevant_for_never()
2139 pub fn coerce_unsized_info(self, did: DefId) -> adjustment::CoerceUnsizedInfo {
2140 queries::coerce_unsized_info::get(self, DUMMY_SP, did)
2143 pub fn associated_item(self, def_id: DefId) -> AssociatedItem {
2144 queries::associated_item::get(self, DUMMY_SP, def_id)
2147 fn associated_item_from_trait_item_ref(self,
2148 parent_def_id: DefId,
2149 trait_item_ref: &hir::TraitItemRef)
2151 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2152 let (kind, has_self) = match trait_item_ref.kind {
2153 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2154 hir::AssociatedItemKind::Method { has_self } => {
2155 (ty::AssociatedKind::Method, has_self)
2157 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2161 name: trait_item_ref.name,
2163 vis: Visibility::from_hir(&hir::Inherited, trait_item_ref.id.node_id, self),
2164 defaultness: trait_item_ref.defaultness,
2166 container: TraitContainer(parent_def_id),
2167 method_has_self_argument: has_self
2171 fn associated_item_from_impl_item_ref(self,
2172 parent_def_id: DefId,
2173 from_trait_impl: bool,
2174 impl_item_ref: &hir::ImplItemRef)
2176 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2177 let (kind, has_self) = match impl_item_ref.kind {
2178 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2179 hir::AssociatedItemKind::Method { has_self } => {
2180 (ty::AssociatedKind::Method, has_self)
2182 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2185 // Trait impl items are always public.
2186 let public = hir::Public;
2187 let vis = if from_trait_impl { &public } else { &impl_item_ref.vis };
2189 ty::AssociatedItem {
2190 name: impl_item_ref.name,
2192 vis: ty::Visibility::from_hir(vis, impl_item_ref.id.node_id, self),
2193 defaultness: impl_item_ref.defaultness,
2195 container: ImplContainer(parent_def_id),
2196 method_has_self_argument: has_self
2200 pub fn associated_item_def_ids(self, def_id: DefId) -> Rc<Vec<DefId>> {
2201 queries::associated_item_def_ids::get(self, DUMMY_SP, def_id)
2204 #[inline] // FIXME(#35870) Avoid closures being unexported due to impl Trait.
2205 pub fn associated_items(self, def_id: DefId)
2206 -> impl Iterator<Item = ty::AssociatedItem> + 'a {
2207 let def_ids = self.associated_item_def_ids(def_id);
2208 (0..def_ids.len()).map(move |i| self.associated_item(def_ids[i]))
2211 /// Returns the trait-ref corresponding to a given impl, or None if it is
2212 /// an inherent impl.
2213 pub fn impl_trait_ref(self, id: DefId) -> Option<TraitRef<'gcx>> {
2214 queries::impl_trait_ref::get(self, DUMMY_SP, id)
2217 /// Returns true if the impls are the same polarity and are implementing
2218 /// a trait which contains no items
2219 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2220 if !self.sess.features.borrow().overlapping_marker_traits {
2223 let trait1_is_empty = self.impl_trait_ref(def_id1)
2224 .map_or(false, |trait_ref| {
2225 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2227 let trait2_is_empty = self.impl_trait_ref(def_id2)
2228 .map_or(false, |trait_ref| {
2229 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2231 self.trait_impl_polarity(def_id1) == self.trait_impl_polarity(def_id2)
2236 // Returns `ty::VariantDef` if `def` refers to a struct,
2237 // or variant or their constructors, panics otherwise.
2238 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2240 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2241 let enum_did = self.parent_def_id(did).unwrap();
2242 self.lookup_adt_def(enum_did).variant_with_id(did)
2244 Def::Struct(did) | Def::Union(did) => {
2245 self.lookup_adt_def(did).struct_variant()
2247 Def::StructCtor(ctor_did, ..) => {
2248 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2249 self.lookup_adt_def(did).struct_variant()
2251 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2255 pub fn def_key(self, id: DefId) -> hir_map::DefKey {
2257 self.hir.def_key(id)
2259 self.sess.cstore.def_key(id)
2263 /// Convert a `DefId` into its fully expanded `DefPath` (every
2264 /// `DefId` is really just an interned def-path).
2266 /// Note that if `id` is not local to this crate, the result will
2267 /// be a non-local `DefPath`.
2268 pub fn def_path(self, id: DefId) -> hir_map::DefPath {
2270 self.hir.def_path(id)
2272 self.sess.cstore.def_path(id)
2277 pub fn def_path_hash(self, def_id: DefId) -> u64 {
2278 if def_id.is_local() {
2279 self.hir.definitions().def_path_hash(def_id.index)
2281 self.sess.cstore.def_path_hash(def_id)
2285 pub fn def_span(self, def_id: DefId) -> Span {
2286 if let Some(id) = self.hir.as_local_node_id(def_id) {
2289 self.sess.cstore.def_span(&self.sess, def_id)
2293 pub fn vis_is_accessible_from(self, vis: Visibility, block: NodeId) -> bool {
2294 vis.is_accessible_from(self.hir.local_def_id(self.hir.get_module_parent(block)), self)
2297 pub fn item_name(self, id: DefId) -> ast::Name {
2298 if let Some(id) = self.hir.as_local_node_id(id) {
2300 } else if id.index == CRATE_DEF_INDEX {
2301 self.sess.cstore.original_crate_name(id.krate)
2303 let def_key = self.sess.cstore.def_key(id);
2304 // The name of a StructCtor is that of its struct parent.
2305 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2306 self.item_name(DefId {
2308 index: def_key.parent.unwrap()
2311 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2312 bug!("item_name: no name for {:?}", self.def_path(id));
2318 // If the given item is in an external crate, looks up its type and adds it to
2319 // the type cache. Returns the type parameters and type.
2320 pub fn item_type(self, did: DefId) -> Ty<'gcx> {
2321 queries::ty::get(self, DUMMY_SP, did)
2324 /// Given the did of a trait, returns its canonical trait ref.
2325 pub fn lookup_trait_def(self, did: DefId) -> &'gcx TraitDef {
2326 queries::trait_def::get(self, DUMMY_SP, did)
2329 /// Given the did of an ADT, return a reference to its definition.
2330 pub fn lookup_adt_def(self, did: DefId) -> &'gcx AdtDef {
2331 queries::adt_def::get(self, DUMMY_SP, did)
2334 /// Given the did of an item, returns its generics.
2335 pub fn item_generics(self, did: DefId) -> &'gcx Generics {
2336 queries::generics::get(self, DUMMY_SP, did)
2339 /// Given the did of an item, returns its full set of predicates.
2340 pub fn item_predicates(self, did: DefId) -> GenericPredicates<'gcx> {
2341 queries::predicates::get(self, DUMMY_SP, did)
2344 /// Given the did of a trait, returns its superpredicates.
2345 pub fn item_super_predicates(self, did: DefId) -> GenericPredicates<'gcx> {
2346 queries::super_predicates::get(self, DUMMY_SP, did)
2349 /// Given the did of an item, returns its MIR, borrowed immutably.
2350 pub fn item_mir(self, did: DefId) -> Ref<'gcx, Mir<'gcx>> {
2351 queries::mir::get(self, DUMMY_SP, did).borrow()
2354 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2355 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2356 -> Ref<'gcx, Mir<'gcx>>
2359 ty::InstanceDef::Item(did) if true => self.item_mir(did),
2360 _ => queries::mir_shims::get(self, DUMMY_SP, instance).borrow(),
2364 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2365 /// Returns None if there is no MIR for the DefId
2366 pub fn maybe_item_mir(self, did: DefId) -> Option<Ref<'gcx, Mir<'gcx>>> {
2367 if did.is_local() && !self.maps.mir.borrow().contains_key(&did) {
2371 if !did.is_local() && !self.sess.cstore.is_item_mir_available(did) {
2375 Some(self.item_mir(did))
2378 /// If `type_needs_drop` returns true, then `ty` is definitely
2379 /// non-copy and *might* have a destructor attached; if it returns
2380 /// false, then `ty` definitely has no destructor (i.e. no drop glue).
2382 /// (Note that this implies that if `ty` has a destructor attached,
2383 /// then `type_needs_drop` will definitely return `true` for `ty`.)
2384 pub fn type_needs_drop_given_env(self,
2386 param_env: &ty::ParameterEnvironment<'gcx>) -> bool {
2387 // Issue #22536: We first query type_moves_by_default. It sees a
2388 // normalized version of the type, and therefore will definitely
2389 // know whether the type implements Copy (and thus needs no
2390 // cleanup/drop/zeroing) ...
2391 let tcx = self.global_tcx();
2392 let implements_copy = !ty.moves_by_default(tcx, param_env, DUMMY_SP);
2394 if implements_copy { return false; }
2396 // ... (issue #22536 continued) but as an optimization, still use
2397 // prior logic of asking if the `needs_drop` bit is set; we need
2398 // not zero non-Copy types if they have no destructor.
2400 // FIXME(#22815): Note that calling `ty::type_contents` is a
2401 // conservative heuristic; it may report that `needs_drop` is set
2402 // when actual type does not actually have a destructor associated
2403 // with it. But since `ty` absolutely did not have the `Copy`
2404 // bound attached (see above), it is sound to treat it as having a
2405 // destructor (e.g. zero its memory on move).
2407 let contents = ty.type_contents(tcx);
2408 debug!("type_needs_drop ty={:?} contents={:?}", ty, contents);
2409 contents.needs_drop(tcx)
2412 /// Get the attributes of a definition.
2413 pub fn get_attrs(self, did: DefId) -> Cow<'gcx, [ast::Attribute]> {
2414 if let Some(id) = self.hir.as_local_node_id(did) {
2415 Cow::Borrowed(self.hir.attrs(id))
2417 Cow::Owned(self.sess.cstore.item_attrs(did))
2421 /// Determine whether an item is annotated with an attribute
2422 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2423 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2426 pub fn item_variances(self, item_id: DefId) -> Rc<Vec<ty::Variance>> {
2427 queries::variances::get(self, DUMMY_SP, item_id)
2430 pub fn trait_has_default_impl(self, trait_def_id: DefId) -> bool {
2431 let def = self.lookup_trait_def(trait_def_id);
2432 def.flags.get().intersects(TraitFlags::HAS_DEFAULT_IMPL)
2435 /// Populates the type context with all the implementations for the given
2436 /// trait if necessary.
2437 pub fn populate_implementations_for_trait_if_necessary(self, trait_id: DefId) {
2438 if trait_id.is_local() {
2442 // The type is not local, hence we are reading this out of
2443 // metadata and don't need to track edges.
2444 let _ignore = self.dep_graph.in_ignore();
2446 let def = self.lookup_trait_def(trait_id);
2447 if def.flags.get().intersects(TraitFlags::HAS_REMOTE_IMPLS) {
2451 debug!("populate_implementations_for_trait_if_necessary: searching for {:?}", def);
2453 for impl_def_id in self.sess.cstore.implementations_of_trait(Some(trait_id)) {
2454 let trait_ref = self.impl_trait_ref(impl_def_id).unwrap();
2456 // Record the trait->implementation mapping.
2457 let parent = self.sess.cstore.impl_parent(impl_def_id).unwrap_or(trait_id);
2458 def.record_remote_impl(self, impl_def_id, trait_ref, parent);
2461 def.flags.set(def.flags.get() | TraitFlags::HAS_REMOTE_IMPLS);
2464 pub fn closure_kind(self, def_id: DefId) -> ty::ClosureKind {
2465 queries::closure_kind::get(self, DUMMY_SP, def_id)
2468 pub fn closure_type(self, def_id: DefId) -> ty::PolyFnSig<'tcx> {
2469 queries::closure_type::get(self, DUMMY_SP, def_id)
2472 /// Given the def_id of an impl, return the def_id of the trait it implements.
2473 /// If it implements no trait, return `None`.
2474 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2475 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2478 /// If the given def ID describes a method belonging to an impl, return the
2479 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2480 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2481 let item = if def_id.krate != LOCAL_CRATE {
2482 if let Some(Def::Method(_)) = self.sess.cstore.describe_def(def_id) {
2483 Some(self.associated_item(def_id))
2488 self.maps.associated_item.borrow().get(&def_id).cloned()
2492 Some(trait_item) => {
2493 match trait_item.container {
2494 TraitContainer(_) => None,
2495 ImplContainer(def_id) => Some(def_id),
2502 /// If the given def ID describes an item belonging to a trait,
2503 /// return the ID of the trait that the trait item belongs to.
2504 /// Otherwise, return `None`.
2505 pub fn trait_of_item(self, def_id: DefId) -> Option<DefId> {
2506 if def_id.krate != LOCAL_CRATE {
2507 return self.sess.cstore.trait_of_item(def_id);
2509 match self.maps.associated_item.borrow().get(&def_id) {
2510 Some(associated_item) => {
2511 match associated_item.container {
2512 TraitContainer(def_id) => Some(def_id),
2513 ImplContainer(_) => None
2520 /// Construct a parameter environment suitable for static contexts or other contexts where there
2521 /// are no free type/lifetime parameters in scope.
2522 pub fn empty_parameter_environment(self) -> ParameterEnvironment<'tcx> {
2524 // for an empty parameter environment, there ARE no free
2525 // regions, so it shouldn't matter what we use for the free id
2526 let free_id_outlive = self.region_maps.node_extent(ast::DUMMY_NODE_ID);
2527 ty::ParameterEnvironment {
2528 free_substs: self.intern_substs(&[]),
2529 caller_bounds: Vec::new(),
2530 implicit_region_bound: self.mk_region(ty::ReEmpty),
2531 free_id_outlive: free_id_outlive,
2532 is_copy_cache: RefCell::new(FxHashMap()),
2533 is_sized_cache: RefCell::new(FxHashMap()),
2537 /// Constructs and returns a substitution that can be applied to move from
2538 /// the "outer" view of a type or method to the "inner" view.
2539 /// In general, this means converting from bound parameters to
2540 /// free parameters. Since we currently represent bound/free type
2541 /// parameters in the same way, this only has an effect on regions.
2542 pub fn construct_free_substs(self, def_id: DefId,
2543 free_id_outlive: CodeExtent)
2544 -> &'gcx Substs<'gcx> {
2546 let substs = Substs::for_item(self.global_tcx(), def_id, |def, _| {
2547 // map bound 'a => free 'a
2548 self.global_tcx().mk_region(ReFree(FreeRegion {
2549 scope: free_id_outlive,
2550 bound_region: def.to_bound_region()
2554 self.global_tcx().mk_param_from_def(def)
2557 debug!("construct_parameter_environment: {:?}", substs);
2561 /// See `ParameterEnvironment` struct def'n for details.
2562 /// If you were using `free_id: NodeId`, you might try `self.region_maps.item_extent(free_id)`
2563 /// for the `free_id_outlive` parameter. (But note that this is not always quite right.)
2564 pub fn construct_parameter_environment(self,
2567 free_id_outlive: CodeExtent)
2568 -> ParameterEnvironment<'gcx>
2571 // Construct the free substs.
2574 let free_substs = self.construct_free_substs(def_id, free_id_outlive);
2577 // Compute the bounds on Self and the type parameters.
2580 let tcx = self.global_tcx();
2581 let generic_predicates = tcx.item_predicates(def_id);
2582 let bounds = generic_predicates.instantiate(tcx, free_substs);
2583 let bounds = tcx.liberate_late_bound_regions(free_id_outlive, &ty::Binder(bounds));
2584 let predicates = bounds.predicates;
2586 // Finally, we have to normalize the bounds in the environment, in
2587 // case they contain any associated type projections. This process
2588 // can yield errors if the put in illegal associated types, like
2589 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2590 // report these errors right here; this doesn't actually feel
2591 // right to me, because constructing the environment feels like a
2592 // kind of a "idempotent" action, but I'm not sure where would be
2593 // a better place. In practice, we construct environments for
2594 // every fn once during type checking, and we'll abort if there
2595 // are any errors at that point, so after type checking you can be
2596 // sure that this will succeed without errors anyway.
2599 let unnormalized_env = ty::ParameterEnvironment {
2600 free_substs: free_substs,
2601 implicit_region_bound: tcx.mk_region(ty::ReScope(free_id_outlive)),
2602 caller_bounds: predicates,
2603 free_id_outlive: free_id_outlive,
2604 is_copy_cache: RefCell::new(FxHashMap()),
2605 is_sized_cache: RefCell::new(FxHashMap()),
2608 let cause = traits::ObligationCause::misc(span, free_id_outlive.node_id(&self.region_maps));
2609 traits::normalize_param_env_or_error(tcx, unnormalized_env, cause)
2612 pub fn node_scope_region(self, id: NodeId) -> &'tcx Region {
2613 self.mk_region(ty::ReScope(self.region_maps.node_extent(id)))
2616 pub fn visit_all_item_likes_in_krate<V,F>(self,
2619 where F: FnMut(DefId) -> DepNode<DefId>, V: ItemLikeVisitor<'gcx>
2621 dep_graph::visit_all_item_likes_in_krate(self.global_tcx(), dep_node_fn, visitor);
2624 /// Invokes `callback` for each body in the krate. This will
2625 /// create a read edge from `DepNode::Krate` to the current task;
2626 /// it is meant to be run in the context of some global task like
2627 /// `BorrowckCrate`. The callback would then create a task like
2628 /// `BorrowckBody(DefId)` to process each individual item.
2629 pub fn visit_all_bodies_in_krate<C>(self, callback: C)
2630 where C: Fn(/* body_owner */ DefId, /* body id */ hir::BodyId),
2632 dep_graph::visit_all_bodies_in_krate(self.global_tcx(), callback)
2635 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2636 /// with the name of the crate containing the impl.
2637 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2638 if impl_did.is_local() {
2639 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2640 Ok(self.hir.span(node_id))
2642 Err(self.sess.cstore.crate_name(impl_did.krate))
2647 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2648 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2649 F: FnOnce(&[hir::Freevar]) -> T,
2651 match self.freevars.borrow().get(&fid) {
2653 Some(d) => f(&d[..])
2658 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
2661 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2662 let parent_id = tcx.hir.get_parent(id);
2663 let parent_def_id = tcx.hir.local_def_id(parent_id);
2664 let parent_item = tcx.hir.expect_item(parent_id);
2665 match parent_item.node {
2666 hir::ItemImpl(.., ref impl_trait_ref, _, ref impl_item_refs) => {
2667 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2669 tcx.associated_item_from_impl_item_ref(parent_def_id,
2670 impl_trait_ref.is_some(),
2672 debug_assert_eq!(assoc_item.def_id, def_id);
2677 hir::ItemTrait(.., ref trait_item_refs) => {
2678 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2680 tcx.associated_item_from_trait_item_ref(parent_def_id, trait_item_ref);
2681 debug_assert_eq!(assoc_item.def_id, def_id);
2687 panic!("unexpected container of associated items: {:?}", r)
2690 panic!("associated item not found for def_id: {:?}", def_id);
2693 /// Calculates the Sized-constraint.
2695 /// As the Sized-constraint of enums can be a *set* of types,
2696 /// the Sized-constraint may need to be a set also. Because introducing
2697 /// a new type of IVar is currently a complex affair, the Sized-constraint
2700 /// In fact, there are only a few options for the constraint:
2701 /// - `bool`, if the type is always Sized
2702 /// - an obviously-unsized type
2703 /// - a type parameter or projection whose Sizedness can't be known
2704 /// - a tuple of type parameters or projections, if there are multiple
2706 /// - a TyError, if a type contained itself. The representability
2707 /// check should catch this case.
2708 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2711 let def = tcx.lookup_adt_def(def_id);
2713 let tys: Vec<_> = def.variants.iter().flat_map(|v| {
2716 let ty = tcx.item_type(f.did);
2717 def.sized_constraint_for_ty(tcx, ty)
2720 let ty = match tys.len() {
2721 _ if tys.references_error() => tcx.types.err,
2722 0 => tcx.types.bool,
2724 _ => tcx.intern_tup(&tys[..], false)
2727 debug!("adt_sized_constraint: {:?} => {:?}", def, ty);
2732 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2735 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2736 let item = tcx.hir.expect_item(id);
2737 let vec: Vec<_> = match item.node {
2738 hir::ItemTrait(.., ref trait_item_refs) => {
2739 trait_item_refs.iter()
2740 .map(|trait_item_ref| trait_item_ref.id)
2741 .map(|id| tcx.hir.local_def_id(id.node_id))
2744 hir::ItemImpl(.., ref impl_item_refs) => {
2745 impl_item_refs.iter()
2746 .map(|impl_item_ref| impl_item_ref.id)
2747 .map(|id| tcx.hir.local_def_id(id.node_id))
2750 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2755 pub fn provide(providers: &mut ty::maps::Providers) {
2756 *providers = ty::maps::Providers {
2758 associated_item_def_ids,
2759 adt_sized_constraint,
2764 pub fn provide_extern(providers: &mut ty::maps::Providers) {
2765 *providers = ty::maps::Providers {
2766 adt_sized_constraint,
2772 /// A map for the local crate mapping each type to a vector of its
2773 /// inherent impls. This is not meant to be used outside of coherence;
2774 /// rather, you should request the vector for a specific type via
2775 /// `ty::queries::inherent_impls::get(def_id)` so as to minimize your
2776 /// dependencies (constructing this map requires touching the entire
2778 #[derive(Clone, Debug)]
2779 pub struct CrateInherentImpls {
2780 pub inherent_impls: DefIdMap<Rc<Vec<DefId>>>,