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::common::MemoizationMap;
35 use util::nodemap::{NodeSet, DefIdMap, FxHashMap};
37 use serialize::{self, Encodable, Encoder};
39 use std::cell::{Cell, RefCell, Ref};
40 use std::collections::BTreeMap;
41 use std::hash::{Hash, Hasher};
45 use std::vec::IntoIter;
47 use syntax::ast::{self, Name, NodeId};
49 use syntax::symbol::{Symbol, InternedString};
50 use syntax_pos::{DUMMY_SP, Span};
51 use rustc_const_math::ConstInt;
53 use rustc_data_structures::accumulate_vec::IntoIter as AccIntoIter;
54 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
58 use hir::itemlikevisit::ItemLikeVisitor;
60 pub use self::sty::{Binder, DebruijnIndex};
61 pub use self::sty::{FnSig, PolyFnSig};
62 pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
63 pub use self::sty::{ClosureSubsts, TypeAndMut};
64 pub use self::sty::{TraitRef, TypeVariants, PolyTraitRef};
65 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
66 pub use self::sty::{ExistentialProjection, PolyExistentialProjection};
67 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
68 pub use self::sty::Issue32330;
69 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid, SkolemizedRegionVid};
70 pub use self::sty::BoundRegion::*;
71 pub use self::sty::InferTy::*;
72 pub use self::sty::Region::*;
73 pub use self::sty::TypeVariants::*;
75 pub use self::contents::TypeContents;
76 pub use self::context::{TyCtxt, GlobalArenas, tls};
77 pub use self::context::{Lift, TypeckTables};
79 pub use self::instance::{Instance, InstanceDef};
81 pub use self::trait_def::{TraitDef, TraitFlags};
83 pub use self::maps::queries;
90 pub mod inhabitedness;
107 mod structural_impls;
112 /// The complete set of all analyses described in this module. This is
113 /// produced by the driver and fed to trans and later passes.
115 /// NB: These contents are being migrated into queries using the
116 /// *on-demand* infrastructure.
118 pub struct CrateAnalysis {
119 pub access_levels: Rc<AccessLevels>,
120 pub reachable: NodeSet,
122 pub glob_map: Option<hir::GlobMap>,
126 pub struct Resolutions {
127 pub freevars: FreevarMap,
128 pub trait_map: TraitMap,
129 pub maybe_unused_trait_imports: NodeSet,
130 pub export_map: ExportMap,
133 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
134 pub enum AssociatedItemContainer {
135 TraitContainer(DefId),
136 ImplContainer(DefId),
139 impl AssociatedItemContainer {
140 pub fn id(&self) -> DefId {
142 TraitContainer(id) => id,
143 ImplContainer(id) => id,
148 /// The "header" of an impl is everything outside the body: a Self type, a trait
149 /// ref (in the case of a trait impl), and a set of predicates (from the
150 /// bounds/where clauses).
151 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
152 pub struct ImplHeader<'tcx> {
153 pub impl_def_id: DefId,
154 pub self_ty: Ty<'tcx>,
155 pub trait_ref: Option<TraitRef<'tcx>>,
156 pub predicates: Vec<Predicate<'tcx>>,
159 impl<'a, 'gcx, 'tcx> ImplHeader<'tcx> {
160 pub fn with_fresh_ty_vars(selcx: &mut traits::SelectionContext<'a, 'gcx, 'tcx>,
164 let tcx = selcx.tcx();
165 let impl_substs = selcx.infcx().fresh_substs_for_item(DUMMY_SP, impl_def_id);
167 let header = ImplHeader {
168 impl_def_id: impl_def_id,
169 self_ty: tcx.item_type(impl_def_id),
170 trait_ref: tcx.impl_trait_ref(impl_def_id),
171 predicates: tcx.item_predicates(impl_def_id).predicates
172 }.subst(tcx, impl_substs);
174 let traits::Normalized { value: mut header, obligations } =
175 traits::normalize(selcx, traits::ObligationCause::dummy(), &header);
177 header.predicates.extend(obligations.into_iter().map(|o| o.predicate));
182 #[derive(Copy, Clone, Debug)]
183 pub struct AssociatedItem {
186 pub kind: AssociatedKind,
188 pub defaultness: hir::Defaultness,
189 pub container: AssociatedItemContainer,
191 /// Whether this is a method with an explicit self
192 /// as its first argument, allowing method calls.
193 pub method_has_self_argument: bool,
196 #[derive(Copy, Clone, PartialEq, Eq, Debug, RustcEncodable, RustcDecodable)]
197 pub enum AssociatedKind {
203 impl AssociatedItem {
204 pub fn def(&self) -> Def {
206 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
207 AssociatedKind::Method => Def::Method(self.def_id),
208 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
212 /// Tests whether the associated item admits a non-trivial implementation
214 pub fn relevant_for_never<'tcx>(&self) -> bool {
216 AssociatedKind::Const => true,
217 AssociatedKind::Type => true,
218 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
219 AssociatedKind::Method => !self.method_has_self_argument,
224 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
225 pub enum Visibility {
226 /// Visible everywhere (including in other crates).
228 /// Visible only in the given crate-local module.
230 /// Not visible anywhere in the local crate. This is the visibility of private external items.
234 pub trait DefIdTree: Copy {
235 fn parent(self, id: DefId) -> Option<DefId>;
237 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
238 if descendant.krate != ancestor.krate {
242 while descendant != ancestor {
243 match self.parent(descendant) {
244 Some(parent) => descendant = parent,
245 None => return false,
252 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
253 fn parent(self, id: DefId) -> Option<DefId> {
254 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
259 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt) -> Self {
261 hir::Public => Visibility::Public,
262 hir::Visibility::Crate => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
263 hir::Visibility::Restricted { ref path, .. } => match path.def {
264 // If there is no resolution, `resolve` will have already reported an error, so
265 // assume that the visibility is public to avoid reporting more privacy errors.
266 Def::Err => Visibility::Public,
267 def => Visibility::Restricted(def.def_id()),
270 Visibility::Restricted(tcx.hir.local_def_id(tcx.hir.get_module_parent(id)))
275 /// Returns true if an item with this visibility is accessible from the given block.
276 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
277 let restriction = match self {
278 // Public items are visible everywhere.
279 Visibility::Public => return true,
280 // Private items from other crates are visible nowhere.
281 Visibility::Invisible => return false,
282 // Restricted items are visible in an arbitrary local module.
283 Visibility::Restricted(other) if other.krate != module.krate => return false,
284 Visibility::Restricted(module) => module,
287 tree.is_descendant_of(module, restriction)
290 /// Returns true if this visibility is at least as accessible as the given visibility
291 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
292 let vis_restriction = match vis {
293 Visibility::Public => return self == Visibility::Public,
294 Visibility::Invisible => return true,
295 Visibility::Restricted(module) => module,
298 self.is_accessible_from(vis_restriction, tree)
302 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
304 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
305 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
306 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
307 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
310 #[derive(Clone, Copy, Debug, RustcDecodable, RustcEncodable)]
311 pub struct MethodCallee<'tcx> {
312 /// Impl method ID, for inherent methods, or trait method ID, otherwise.
315 pub substs: &'tcx Substs<'tcx>
318 /// With method calls, we store some extra information in
319 /// side tables (i.e method_map). We use
320 /// MethodCall as a key to index into these tables instead of
321 /// just directly using the expression's NodeId. The reason
322 /// for this being that we may apply adjustments (coercions)
323 /// with the resulting expression also needing to use the
324 /// side tables. The problem with this is that we don't
325 /// assign a separate NodeId to this new expression
326 /// and so it would clash with the base expression if both
327 /// needed to add to the side tables. Thus to disambiguate
328 /// we also keep track of whether there's an adjustment in
330 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
331 pub struct MethodCall {
337 pub fn expr(id: NodeId) -> MethodCall {
344 pub fn autoderef(expr_id: NodeId, autoderef: u32) -> MethodCall {
347 autoderef: 1 + autoderef
352 // maps from an expression id that corresponds to a method call to the details
353 // of the method to be invoked
354 pub type MethodMap<'tcx> = FxHashMap<MethodCall, MethodCallee<'tcx>>;
356 // Contains information needed to resolve types and (in the future) look up
357 // the types of AST nodes.
358 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
359 pub struct CReaderCacheKey {
364 /// Describes the fragment-state associated with a NodeId.
366 /// Currently only unfragmented paths have entries in the table,
367 /// but longer-term this enum is expected to expand to also
368 /// include data for fragmented paths.
369 #[derive(Copy, Clone, Debug)]
370 pub enum FragmentInfo {
371 Moved { var: NodeId, move_expr: NodeId },
372 Assigned { var: NodeId, assign_expr: NodeId, assignee_id: NodeId },
375 // Flags that we track on types. These flags are propagated upwards
376 // through the type during type construction, so that we can quickly
377 // check whether the type has various kinds of types in it without
378 // recursing over the type itself.
380 flags TypeFlags: u32 {
381 const HAS_PARAMS = 1 << 0,
382 const HAS_SELF = 1 << 1,
383 const HAS_TY_INFER = 1 << 2,
384 const HAS_RE_INFER = 1 << 3,
385 const HAS_RE_SKOL = 1 << 4,
386 const HAS_RE_EARLY_BOUND = 1 << 5,
387 const HAS_FREE_REGIONS = 1 << 6,
388 const HAS_TY_ERR = 1 << 7,
389 const HAS_PROJECTION = 1 << 8,
390 const HAS_TY_CLOSURE = 1 << 9,
392 // true if there are "names" of types and regions and so forth
393 // that are local to a particular fn
394 const HAS_LOCAL_NAMES = 1 << 10,
396 // Present if the type belongs in a local type context.
397 // Only set for TyInfer other than Fresh.
398 const KEEP_IN_LOCAL_TCX = 1 << 11,
400 // Is there a projection that does not involve a bound region?
401 // Currently we can't normalize projections w/ bound regions.
402 const HAS_NORMALIZABLE_PROJECTION = 1 << 12,
404 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
405 TypeFlags::HAS_SELF.bits |
406 TypeFlags::HAS_RE_EARLY_BOUND.bits,
408 // Flags representing the nominal content of a type,
409 // computed by FlagsComputation. If you add a new nominal
410 // flag, it should be added here too.
411 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
412 TypeFlags::HAS_SELF.bits |
413 TypeFlags::HAS_TY_INFER.bits |
414 TypeFlags::HAS_RE_INFER.bits |
415 TypeFlags::HAS_RE_SKOL.bits |
416 TypeFlags::HAS_RE_EARLY_BOUND.bits |
417 TypeFlags::HAS_FREE_REGIONS.bits |
418 TypeFlags::HAS_TY_ERR.bits |
419 TypeFlags::HAS_PROJECTION.bits |
420 TypeFlags::HAS_TY_CLOSURE.bits |
421 TypeFlags::HAS_LOCAL_NAMES.bits |
422 TypeFlags::KEEP_IN_LOCAL_TCX.bits,
424 // Caches for type_is_sized, type_moves_by_default
425 const SIZEDNESS_CACHED = 1 << 16,
426 const IS_SIZED = 1 << 17,
427 const MOVENESS_CACHED = 1 << 18,
428 const MOVES_BY_DEFAULT = 1 << 19,
432 pub struct TyS<'tcx> {
433 pub sty: TypeVariants<'tcx>,
434 pub flags: Cell<TypeFlags>,
436 // the maximal depth of any bound regions appearing in this type.
440 impl<'tcx> PartialEq for TyS<'tcx> {
442 fn eq(&self, other: &TyS<'tcx>) -> bool {
443 // (self as *const _) == (other as *const _)
444 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
447 impl<'tcx> Eq for TyS<'tcx> {}
449 impl<'tcx> Hash for TyS<'tcx> {
450 fn hash<H: Hasher>(&self, s: &mut H) {
451 (self as *const TyS).hash(s)
455 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for ty::TyS<'tcx> {
456 fn hash_stable<W: StableHasherResult>(&self,
457 hcx: &mut StableHashingContext<'a, 'tcx>,
458 hasher: &mut StableHasher<W>) {
462 // The other fields just provide fast access to information that is
463 // also contained in `sty`, so no need to hash them.
468 sty.hash_stable(hcx, hasher);
472 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
474 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
475 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
477 /// A wrapper for slices with the additional invariant
478 /// that the slice is interned and no other slice with
479 /// the same contents can exist in the same context.
480 /// This means we can use pointer + length for both
481 /// equality comparisons and hashing.
482 #[derive(Debug, RustcEncodable)]
483 pub struct Slice<T>([T]);
485 impl<T> PartialEq for Slice<T> {
487 fn eq(&self, other: &Slice<T>) -> bool {
488 (&self.0 as *const [T]) == (&other.0 as *const [T])
491 impl<T> Eq for Slice<T> {}
493 impl<T> Hash for Slice<T> {
494 fn hash<H: Hasher>(&self, s: &mut H) {
495 (self.as_ptr(), self.len()).hash(s)
499 impl<T> Deref for Slice<T> {
501 fn deref(&self) -> &[T] {
506 impl<'a, T> IntoIterator for &'a Slice<T> {
508 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
509 fn into_iter(self) -> Self::IntoIter {
514 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {}
517 pub fn empty<'a>() -> &'a Slice<T> {
519 mem::transmute(slice::from_raw_parts(0x1 as *const T, 0))
524 /// Upvars do not get their own node-id. Instead, we use the pair of
525 /// the original var id (that is, the root variable that is referenced
526 /// by the upvar) and the id of the closure expression.
527 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
530 pub closure_expr_id: NodeId,
533 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
534 pub enum BorrowKind {
535 /// Data must be immutable and is aliasable.
538 /// Data must be immutable but not aliasable. This kind of borrow
539 /// cannot currently be expressed by the user and is used only in
540 /// implicit closure bindings. It is needed when the closure
541 /// is borrowing or mutating a mutable referent, e.g.:
543 /// let x: &mut isize = ...;
544 /// let y = || *x += 5;
546 /// If we were to try to translate this closure into a more explicit
547 /// form, we'd encounter an error with the code as written:
549 /// struct Env { x: & &mut isize }
550 /// let x: &mut isize = ...;
551 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
552 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
554 /// This is then illegal because you cannot mutate a `&mut` found
555 /// in an aliasable location. To solve, you'd have to translate with
556 /// an `&mut` borrow:
558 /// struct Env { x: & &mut isize }
559 /// let x: &mut isize = ...;
560 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
561 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
563 /// Now the assignment to `**env.x` is legal, but creating a
564 /// mutable pointer to `x` is not because `x` is not mutable. We
565 /// could fix this by declaring `x` as `let mut x`. This is ok in
566 /// user code, if awkward, but extra weird for closures, since the
567 /// borrow is hidden.
569 /// So we introduce a "unique imm" borrow -- the referent is
570 /// immutable, but not aliasable. This solves the problem. For
571 /// simplicity, we don't give users the way to express this
572 /// borrow, it's just used when translating closures.
575 /// Data is mutable and not aliasable.
579 /// Information describing the capture of an upvar. This is computed
580 /// during `typeck`, specifically by `regionck`.
581 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
582 pub enum UpvarCapture<'tcx> {
583 /// Upvar is captured by value. This is always true when the
584 /// closure is labeled `move`, but can also be true in other cases
585 /// depending on inference.
588 /// Upvar is captured by reference.
589 ByRef(UpvarBorrow<'tcx>),
592 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
593 pub struct UpvarBorrow<'tcx> {
594 /// The kind of borrow: by-ref upvars have access to shared
595 /// immutable borrows, which are not part of the normal language
597 pub kind: BorrowKind,
599 /// Region of the resulting reference.
600 pub region: &'tcx ty::Region,
603 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
605 #[derive(Copy, Clone)]
606 pub struct ClosureUpvar<'tcx> {
612 #[derive(Clone, Copy, PartialEq)]
613 pub enum IntVarValue {
615 UintType(ast::UintTy),
618 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
619 pub struct TypeParameterDef {
623 pub has_default: bool,
624 pub object_lifetime_default: ObjectLifetimeDefault,
626 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
627 /// on generic parameter `T`, asserts data behind the parameter
628 /// `T` won't be accessed during the parent type's `Drop` impl.
629 pub pure_wrt_drop: bool,
632 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
633 pub struct RegionParameterDef {
637 pub issue_32330: Option<ty::Issue32330>,
639 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
640 /// on generic parameter `'a`, asserts data of lifetime `'a`
641 /// won't be accessed during the parent type's `Drop` impl.
642 pub pure_wrt_drop: bool,
645 impl RegionParameterDef {
646 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
647 ty::EarlyBoundRegion {
653 pub fn to_bound_region(&self) -> ty::BoundRegion {
654 ty::BoundRegion::BrNamed(self.def_id, self.name)
658 /// Information about the formal type/lifetime parameters associated
659 /// with an item or method. Analogous to hir::Generics.
660 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
661 pub struct Generics {
662 pub parent: Option<DefId>,
663 pub parent_regions: u32,
664 pub parent_types: u32,
665 pub regions: Vec<RegionParameterDef>,
666 pub types: Vec<TypeParameterDef>,
668 /// Reverse map to each `TypeParameterDef`'s `index` field, from
669 /// `def_id.index` (`def_id.krate` is the same as the item's).
670 pub type_param_to_index: BTreeMap<DefIndex, u32>,
676 pub fn parent_count(&self) -> usize {
677 self.parent_regions as usize + self.parent_types as usize
680 pub fn own_count(&self) -> usize {
681 self.regions.len() + self.types.len()
684 pub fn count(&self) -> usize {
685 self.parent_count() + self.own_count()
688 pub fn region_param(&self, param: &EarlyBoundRegion) -> &RegionParameterDef {
689 assert_eq!(self.parent_count(), 0);
690 &self.regions[param.index as usize - self.has_self as usize]
693 pub fn type_param(&self, param: &ParamTy) -> &TypeParameterDef {
694 assert_eq!(self.parent_count(), 0);
695 &self.types[param.idx as usize - self.has_self as usize - self.regions.len()]
699 /// Bounds on generics.
700 #[derive(Clone, Default)]
701 pub struct GenericPredicates<'tcx> {
702 pub parent: Option<DefId>,
703 pub predicates: Vec<Predicate<'tcx>>,
706 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
707 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
709 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
710 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
711 -> InstantiatedPredicates<'tcx> {
712 let mut instantiated = InstantiatedPredicates::empty();
713 self.instantiate_into(tcx, &mut instantiated, substs);
716 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
717 -> InstantiatedPredicates<'tcx> {
718 InstantiatedPredicates {
719 predicates: self.predicates.subst(tcx, substs)
723 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
724 instantiated: &mut InstantiatedPredicates<'tcx>,
725 substs: &Substs<'tcx>) {
726 if let Some(def_id) = self.parent {
727 tcx.item_predicates(def_id).instantiate_into(tcx, instantiated, substs);
729 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
732 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
733 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
734 -> InstantiatedPredicates<'tcx>
736 assert_eq!(self.parent, None);
737 InstantiatedPredicates {
738 predicates: self.predicates.iter().map(|pred| {
739 pred.subst_supertrait(tcx, poly_trait_ref)
745 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
746 pub enum Predicate<'tcx> {
747 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
748 /// the `Self` type of the trait reference and `A`, `B`, and `C`
749 /// would be the type parameters.
750 Trait(PolyTraitPredicate<'tcx>),
752 /// where `T1 == T2`.
753 Equate(PolyEquatePredicate<'tcx>),
756 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
759 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
761 /// where <T as TraitRef>::Name == X, approximately.
762 /// See `ProjectionPredicate` struct for details.
763 Projection(PolyProjectionPredicate<'tcx>),
766 WellFormed(Ty<'tcx>),
768 /// trait must be object-safe
771 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
772 /// for some substitutions `...` and T being a closure type.
773 /// Satisfied (or refuted) once we know the closure's kind.
774 ClosureKind(DefId, ClosureKind),
777 Subtype(PolySubtypePredicate<'tcx>),
780 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
781 /// Performs a substitution suitable for going from a
782 /// poly-trait-ref to supertraits that must hold if that
783 /// poly-trait-ref holds. This is slightly different from a normal
784 /// substitution in terms of what happens with bound regions. See
785 /// lengthy comment below for details.
786 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
787 trait_ref: &ty::PolyTraitRef<'tcx>)
788 -> ty::Predicate<'tcx>
790 // The interaction between HRTB and supertraits is not entirely
791 // obvious. Let me walk you (and myself) through an example.
793 // Let's start with an easy case. Consider two traits:
795 // trait Foo<'a> : Bar<'a,'a> { }
796 // trait Bar<'b,'c> { }
798 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
799 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
800 // knew that `Foo<'x>` (for any 'x) then we also know that
801 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
802 // normal substitution.
804 // In terms of why this is sound, the idea is that whenever there
805 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
806 // holds. So if there is an impl of `T:Foo<'a>` that applies to
807 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
810 // Another example to be careful of is this:
812 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
813 // trait Bar1<'b,'c> { }
815 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
816 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
817 // reason is similar to the previous example: any impl of
818 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
819 // basically we would want to collapse the bound lifetimes from
820 // the input (`trait_ref`) and the supertraits.
822 // To achieve this in practice is fairly straightforward. Let's
823 // consider the more complicated scenario:
825 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
826 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
827 // where both `'x` and `'b` would have a DB index of 1.
828 // The substitution from the input trait-ref is therefore going to be
829 // `'a => 'x` (where `'x` has a DB index of 1).
830 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
831 // early-bound parameter and `'b' is a late-bound parameter with a
833 // - If we replace `'a` with `'x` from the input, it too will have
834 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
835 // just as we wanted.
837 // There is only one catch. If we just apply the substitution `'a
838 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
839 // adjust the DB index because we substituting into a binder (it
840 // tries to be so smart...) resulting in `for<'x> for<'b>
841 // Bar1<'x,'b>` (we have no syntax for this, so use your
842 // imagination). Basically the 'x will have DB index of 2 and 'b
843 // will have DB index of 1. Not quite what we want. So we apply
844 // the substitution to the *contents* of the trait reference,
845 // rather than the trait reference itself (put another way, the
846 // substitution code expects equal binding levels in the values
847 // from the substitution and the value being substituted into, and
848 // this trick achieves that).
850 let substs = &trait_ref.0.substs;
852 Predicate::Trait(ty::Binder(ref data)) =>
853 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
854 Predicate::Equate(ty::Binder(ref data)) =>
855 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
856 Predicate::Subtype(ty::Binder(ref data)) =>
857 Predicate::Subtype(ty::Binder(data.subst(tcx, substs))),
858 Predicate::RegionOutlives(ty::Binder(ref data)) =>
859 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
860 Predicate::TypeOutlives(ty::Binder(ref data)) =>
861 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
862 Predicate::Projection(ty::Binder(ref data)) =>
863 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
864 Predicate::WellFormed(data) =>
865 Predicate::WellFormed(data.subst(tcx, substs)),
866 Predicate::ObjectSafe(trait_def_id) =>
867 Predicate::ObjectSafe(trait_def_id),
868 Predicate::ClosureKind(closure_def_id, kind) =>
869 Predicate::ClosureKind(closure_def_id, kind),
874 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
875 pub struct TraitPredicate<'tcx> {
876 pub trait_ref: TraitRef<'tcx>
878 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
880 impl<'tcx> TraitPredicate<'tcx> {
881 pub fn def_id(&self) -> DefId {
882 self.trait_ref.def_id
885 /// Creates the dep-node for selecting/evaluating this trait reference.
886 fn dep_node(&self) -> DepNode<DefId> {
887 // Extact the trait-def and first def-id from inputs. See the
888 // docs for `DepNode::TraitSelect` for more information.
889 let trait_def_id = self.def_id();
892 .flat_map(|t| t.walk())
893 .filter_map(|t| match t.sty {
894 ty::TyAdt(adt_def, _) => Some(adt_def.did),
898 .unwrap_or(trait_def_id);
899 DepNode::TraitSelect {
900 trait_def_id: trait_def_id,
901 input_def_id: input_def_id
905 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
906 self.trait_ref.input_types()
909 pub fn self_ty(&self) -> Ty<'tcx> {
910 self.trait_ref.self_ty()
914 impl<'tcx> PolyTraitPredicate<'tcx> {
915 pub fn def_id(&self) -> DefId {
916 // ok to skip binder since trait def-id does not care about regions
920 pub fn dep_node(&self) -> DepNode<DefId> {
921 // ok to skip binder since depnode does not care about regions
926 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
927 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
928 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
930 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
931 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
932 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
933 pub type PolyRegionOutlivesPredicate<'tcx> = PolyOutlivesPredicate<&'tcx ty::Region,
935 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, &'tcx ty::Region>;
937 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
938 pub struct SubtypePredicate<'tcx> {
939 pub a_is_expected: bool,
943 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
945 /// This kind of predicate has no *direct* correspondent in the
946 /// syntax, but it roughly corresponds to the syntactic forms:
948 /// 1. `T : TraitRef<..., Item=Type>`
949 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
951 /// In particular, form #1 is "desugared" to the combination of a
952 /// normal trait predicate (`T : TraitRef<...>`) and one of these
953 /// predicates. Form #2 is a broader form in that it also permits
954 /// equality between arbitrary types. Processing an instance of Form
955 /// #2 eventually yields one of these `ProjectionPredicate`
956 /// instances to normalize the LHS.
957 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
958 pub struct ProjectionPredicate<'tcx> {
959 pub projection_ty: ProjectionTy<'tcx>,
963 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
965 impl<'tcx> PolyProjectionPredicate<'tcx> {
966 pub fn item_name(&self) -> Name {
967 self.0.projection_ty.item_name // safe to skip the binder to access a name
971 pub trait ToPolyTraitRef<'tcx> {
972 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
975 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
976 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
977 assert!(!self.has_escaping_regions());
978 ty::Binder(self.clone())
982 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
983 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
984 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
988 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
989 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
990 // Note: unlike with TraitRef::to_poly_trait_ref(),
991 // self.0.trait_ref is permitted to have escaping regions.
992 // This is because here `self` has a `Binder` and so does our
993 // return value, so we are preserving the number of binding
995 ty::Binder(self.0.projection_ty.trait_ref)
999 pub trait ToPredicate<'tcx> {
1000 fn to_predicate(&self) -> Predicate<'tcx>;
1003 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1004 fn to_predicate(&self) -> Predicate<'tcx> {
1005 // we're about to add a binder, so let's check that we don't
1006 // accidentally capture anything, or else that might be some
1007 // weird debruijn accounting.
1008 assert!(!self.has_escaping_regions());
1010 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
1011 trait_ref: self.clone()
1016 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1017 fn to_predicate(&self) -> Predicate<'tcx> {
1018 ty::Predicate::Trait(self.to_poly_trait_predicate())
1022 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
1023 fn to_predicate(&self) -> Predicate<'tcx> {
1024 Predicate::Equate(self.clone())
1028 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1029 fn to_predicate(&self) -> Predicate<'tcx> {
1030 Predicate::RegionOutlives(self.clone())
1034 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1035 fn to_predicate(&self) -> Predicate<'tcx> {
1036 Predicate::TypeOutlives(self.clone())
1040 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1041 fn to_predicate(&self) -> Predicate<'tcx> {
1042 Predicate::Projection(self.clone())
1046 impl<'tcx> Predicate<'tcx> {
1047 /// Iterates over the types in this predicate. Note that in all
1048 /// cases this is skipping over a binder, so late-bound regions
1049 /// with depth 0 are bound by the predicate.
1050 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1051 let vec: Vec<_> = match *self {
1052 ty::Predicate::Trait(ref data) => {
1053 data.skip_binder().input_types().collect()
1055 ty::Predicate::Equate(ty::Binder(ref data)) => {
1056 vec![data.0, data.1]
1058 ty::Predicate::Subtype(ty::Binder(SubtypePredicate { a, b, a_is_expected: _ })) => {
1061 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
1064 ty::Predicate::RegionOutlives(..) => {
1067 ty::Predicate::Projection(ref data) => {
1068 let trait_inputs = data.0.projection_ty.trait_ref.input_types();
1069 trait_inputs.chain(Some(data.0.ty)).collect()
1071 ty::Predicate::WellFormed(data) => {
1074 ty::Predicate::ObjectSafe(_trait_def_id) => {
1077 ty::Predicate::ClosureKind(_closure_def_id, _kind) => {
1082 // The only reason to collect into a vector here is that I was
1083 // too lazy to make the full (somewhat complicated) iterator
1084 // type that would be needed here. But I wanted this fn to
1085 // return an iterator conceptually, rather than a `Vec`, so as
1086 // to be closer to `Ty::walk`.
1090 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1092 Predicate::Trait(ref t) => {
1093 Some(t.to_poly_trait_ref())
1095 Predicate::Projection(..) |
1096 Predicate::Equate(..) |
1097 Predicate::Subtype(..) |
1098 Predicate::RegionOutlives(..) |
1099 Predicate::WellFormed(..) |
1100 Predicate::ObjectSafe(..) |
1101 Predicate::ClosureKind(..) |
1102 Predicate::TypeOutlives(..) => {
1109 /// Represents the bounds declared on a particular set of type
1110 /// parameters. Should eventually be generalized into a flag list of
1111 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1112 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1113 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1114 /// the `GenericPredicates` are expressed in terms of the bound type
1115 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1116 /// represented a set of bounds for some particular instantiation,
1117 /// meaning that the generic parameters have been substituted with
1122 /// struct Foo<T,U:Bar<T>> { ... }
1124 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1125 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1126 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1127 /// [usize:Bar<isize>]]`.
1129 pub struct InstantiatedPredicates<'tcx> {
1130 pub predicates: Vec<Predicate<'tcx>>,
1133 impl<'tcx> InstantiatedPredicates<'tcx> {
1134 pub fn empty() -> InstantiatedPredicates<'tcx> {
1135 InstantiatedPredicates { predicates: vec![] }
1138 pub fn is_empty(&self) -> bool {
1139 self.predicates.is_empty()
1143 /// When type checking, we use the `ParameterEnvironment` to track
1144 /// details about the type/lifetime parameters that are in scope.
1145 /// It primarily stores the bounds information.
1147 /// Note: This information might seem to be redundant with the data in
1148 /// `tcx.ty_param_defs`, but it is not. That table contains the
1149 /// parameter definitions from an "outside" perspective, but this
1150 /// struct will contain the bounds for a parameter as seen from inside
1151 /// the function body. Currently the only real distinction is that
1152 /// bound lifetime parameters are replaced with free ones, but in the
1153 /// future I hope to refine the representation of types so as to make
1154 /// more distinctions clearer.
1156 pub struct ParameterEnvironment<'tcx> {
1157 /// See `construct_free_substs` for details.
1158 pub free_substs: &'tcx Substs<'tcx>,
1160 /// Each type parameter has an implicit region bound that
1161 /// indicates it must outlive at least the function body (the user
1162 /// may specify stronger requirements). This field indicates the
1163 /// region of the callee.
1164 pub implicit_region_bound: &'tcx ty::Region,
1166 /// Obligations that the caller must satisfy. This is basically
1167 /// the set of bounds on the in-scope type parameters, translated
1168 /// into Obligations, and elaborated and normalized.
1169 pub caller_bounds: Vec<ty::Predicate<'tcx>>,
1171 /// Scope that is attached to free regions for this scope. This
1172 /// is usually the id of the fn body, but for more abstract scopes
1173 /// like structs we often use the node-id of the struct.
1175 /// FIXME(#3696). It would be nice to refactor so that free
1176 /// regions don't have this implicit scope and instead introduce
1177 /// relationships in the environment.
1178 pub free_id_outlive: CodeExtent,
1180 /// A cache for `moves_by_default`.
1181 pub is_copy_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1183 /// A cache for `type_is_sized`
1184 pub is_sized_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1187 impl<'a, 'tcx> ParameterEnvironment<'tcx> {
1188 pub fn with_caller_bounds(&self,
1189 caller_bounds: Vec<ty::Predicate<'tcx>>)
1190 -> ParameterEnvironment<'tcx>
1192 ParameterEnvironment {
1193 free_substs: self.free_substs,
1194 implicit_region_bound: self.implicit_region_bound,
1195 caller_bounds: caller_bounds,
1196 free_id_outlive: self.free_id_outlive,
1197 is_copy_cache: RefCell::new(FxHashMap()),
1198 is_sized_cache: RefCell::new(FxHashMap()),
1202 /// Construct a parameter environment given an item, impl item, or trait item
1203 pub fn for_item(tcx: TyCtxt<'a, 'tcx, 'tcx>, id: NodeId)
1204 -> ParameterEnvironment<'tcx> {
1205 match tcx.hir.find(id) {
1206 Some(hir_map::NodeImplItem(ref impl_item)) => {
1207 match impl_item.node {
1208 hir::ImplItemKind::Type(_) | hir::ImplItemKind::Const(..) => {
1209 // associated types don't have their own entry (for some reason),
1210 // so for now just grab environment for the impl
1211 let impl_id = tcx.hir.get_parent(id);
1212 let impl_def_id = tcx.hir.local_def_id(impl_id);
1213 tcx.construct_parameter_environment(impl_item.span,
1215 tcx.region_maps.item_extent(id))
1217 hir::ImplItemKind::Method(_, ref body) => {
1218 tcx.construct_parameter_environment(
1220 tcx.hir.local_def_id(id),
1221 tcx.region_maps.call_site_extent(id, body.node_id))
1225 Some(hir_map::NodeTraitItem(trait_item)) => {
1226 match trait_item.node {
1227 hir::TraitItemKind::Type(..) | hir::TraitItemKind::Const(..) => {
1228 // associated types don't have their own entry (for some reason),
1229 // so for now just grab environment for the trait
1230 let trait_id = tcx.hir.get_parent(id);
1231 let trait_def_id = tcx.hir.local_def_id(trait_id);
1232 tcx.construct_parameter_environment(trait_item.span,
1234 tcx.region_maps.item_extent(id))
1236 hir::TraitItemKind::Method(_, ref body) => {
1237 // Use call-site for extent (unless this is a
1238 // trait method with no default; then fallback
1239 // to the method id).
1240 let extent = if let hir::TraitMethod::Provided(body_id) = *body {
1241 // default impl: use call_site extent as free_id_outlive bound.
1242 tcx.region_maps.call_site_extent(id, body_id.node_id)
1244 // no default impl: use item extent as free_id_outlive bound.
1245 tcx.region_maps.item_extent(id)
1247 tcx.construct_parameter_environment(
1249 tcx.hir.local_def_id(id),
1254 Some(hir_map::NodeItem(item)) => {
1256 hir::ItemFn(.., body_id) => {
1257 // We assume this is a function.
1258 let fn_def_id = tcx.hir.local_def_id(id);
1260 tcx.construct_parameter_environment(
1263 tcx.region_maps.call_site_extent(id, body_id.node_id))
1266 hir::ItemStruct(..) |
1267 hir::ItemUnion(..) |
1270 hir::ItemConst(..) |
1271 hir::ItemStatic(..) => {
1272 let def_id = tcx.hir.local_def_id(id);
1273 tcx.construct_parameter_environment(item.span,
1275 tcx.region_maps.item_extent(id))
1277 hir::ItemTrait(..) => {
1278 let def_id = tcx.hir.local_def_id(id);
1279 tcx.construct_parameter_environment(item.span,
1281 tcx.region_maps.item_extent(id))
1284 span_bug!(item.span,
1285 "ParameterEnvironment::for_item():
1286 can't create a parameter \
1287 environment for this kind of item")
1291 Some(hir_map::NodeExpr(expr)) => {
1292 // This is a convenience to allow closures to work.
1293 if let hir::ExprClosure(.., body, _) = expr.node {
1294 let def_id = tcx.hir.local_def_id(id);
1295 let base_def_id = tcx.closure_base_def_id(def_id);
1296 tcx.construct_parameter_environment(
1299 tcx.region_maps.call_site_extent(id, body.node_id))
1301 tcx.empty_parameter_environment()
1304 Some(hir_map::NodeForeignItem(item)) => {
1305 let def_id = tcx.hir.local_def_id(id);
1306 tcx.construct_parameter_environment(item.span,
1310 Some(hir_map::NodeStructCtor(..)) |
1311 Some(hir_map::NodeVariant(..)) => {
1312 let def_id = tcx.hir.local_def_id(id);
1313 tcx.construct_parameter_environment(tcx.hir.span(id),
1318 bug!("ParameterEnvironment::from_item(): \
1319 `{}` = {:?} is unsupported",
1320 tcx.hir.node_to_string(id), it)
1326 #[derive(Copy, Clone, Debug)]
1327 pub struct Destructor {
1328 /// The def-id of the destructor method
1330 /// Invoking the destructor of a dtorck type during usual cleanup
1331 /// (e.g. the glue emitted for stack unwinding) requires all
1332 /// lifetimes in the type-structure of `adt` to strictly outlive
1333 /// the adt value itself.
1335 /// If `adt` is not dtorck, then the adt's destructor can be
1336 /// invoked even when there are lifetimes in the type-structure of
1337 /// `adt` that do not strictly outlive the adt value itself.
1338 /// (This allows programs to make cyclic structures without
1339 /// resorting to unsafe means; see RFCs 769 and 1238).
1340 pub is_dtorck: bool,
1344 flags AdtFlags: u32 {
1345 const NO_ADT_FLAGS = 0,
1346 const IS_ENUM = 1 << 0,
1347 const IS_PHANTOM_DATA = 1 << 1,
1348 const IS_FUNDAMENTAL = 1 << 2,
1349 const IS_UNION = 1 << 3,
1350 const IS_BOX = 1 << 4,
1355 pub struct VariantDef {
1356 /// The variant's DefId. If this is a tuple-like struct,
1357 /// this is the DefId of the struct's ctor.
1359 pub name: Name, // struct's name if this is a struct
1360 pub discr: VariantDiscr,
1361 pub fields: Vec<FieldDef>,
1362 pub ctor_kind: CtorKind,
1365 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1366 pub enum VariantDiscr {
1367 /// Explicit value for this variant, i.e. `X = 123`.
1368 /// The `DefId` corresponds to the embedded constant.
1371 /// The previous variant's discriminant plus one.
1372 /// For efficiency reasons, the distance from the
1373 /// last `Explicit` discriminant is being stored,
1374 /// or `0` for the first variant, if it has none.
1379 pub struct FieldDef {
1382 pub vis: Visibility,
1385 /// The definition of an abstract data type - a struct or enum.
1387 /// These are all interned (by intern_adt_def) into the adt_defs
1391 pub variants: Vec<VariantDef>,
1393 pub repr: ReprOptions,
1396 impl PartialEq for AdtDef {
1397 // AdtDef are always interned and this is part of TyS equality
1399 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1402 impl Eq for AdtDef {}
1404 impl Hash for AdtDef {
1406 fn hash<H: Hasher>(&self, s: &mut H) {
1407 (self as *const AdtDef).hash(s)
1411 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1412 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1417 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1420 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for AdtDef {
1421 fn hash_stable<W: StableHasherResult>(&self,
1422 hcx: &mut StableHashingContext<'a, 'tcx>,
1423 hasher: &mut StableHasher<W>) {
1431 did.hash_stable(hcx, hasher);
1432 variants.hash_stable(hcx, hasher);
1433 flags.hash_stable(hcx, hasher);
1434 repr.hash_stable(hcx, hasher);
1438 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1439 pub enum AdtKind { Struct, Union, Enum }
1441 /// Represents the repr options provided by the user,
1442 #[derive(Copy, Clone, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1443 pub struct ReprOptions {
1447 pub int: Option<attr::IntType>,
1448 // Internal only for now. If true, don't reorder fields.
1452 impl_stable_hash_for!(struct ReprOptions {
1461 pub fn new(tcx: TyCtxt, did: DefId) -> ReprOptions {
1462 let mut ret = ReprOptions::default();
1464 for attr in tcx.get_attrs(did).iter() {
1465 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1467 attr::ReprExtern => ret.c = true,
1468 attr::ReprPacked => ret.packed = true,
1469 attr::ReprSimd => ret.simd = true,
1470 attr::ReprInt(i) => ret.int = Some(i),
1475 // FIXME(eddyb) This is deprecated and should be removed.
1476 if tcx.has_attr(did, "simd") {
1480 // This is here instead of layout because the choice must make it into metadata.
1481 ret.linear = !tcx.consider_optimizing(|| format!("Reorder fields of {:?}",
1482 tcx.item_path_str(did)));
1486 pub fn discr_type(&self) -> attr::IntType {
1487 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Is))
1490 /// Returns true if this `#[repr()]` should inhabit "smart enum
1491 /// layout" optimizations, such as representing `Foo<&T>` as a
1493 pub fn inhibit_enum_layout_opt(&self) -> bool {
1494 self.c || self.int.is_some()
1498 impl<'a, 'gcx, 'tcx> AdtDef {
1502 variants: Vec<VariantDef>,
1503 repr: ReprOptions) -> Self {
1504 let mut flags = AdtFlags::NO_ADT_FLAGS;
1505 let attrs = tcx.get_attrs(did);
1506 if attr::contains_name(&attrs, "fundamental") {
1507 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1509 if Some(did) == tcx.lang_items.phantom_data() {
1510 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1512 if Some(did) == tcx.lang_items.owned_box() {
1513 flags = flags | AdtFlags::IS_BOX;
1516 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
1517 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
1518 AdtKind::Struct => {}
1529 pub fn is_struct(&self) -> bool {
1530 !self.is_union() && !self.is_enum()
1534 pub fn is_union(&self) -> bool {
1535 self.flags.intersects(AdtFlags::IS_UNION)
1539 pub fn is_enum(&self) -> bool {
1540 self.flags.intersects(AdtFlags::IS_ENUM)
1543 /// Returns the kind of the ADT - Struct or Enum.
1545 pub fn adt_kind(&self) -> AdtKind {
1548 } else if self.is_union() {
1555 pub fn descr(&self) -> &'static str {
1556 match self.adt_kind() {
1557 AdtKind::Struct => "struct",
1558 AdtKind::Union => "union",
1559 AdtKind::Enum => "enum",
1563 pub fn variant_descr(&self) -> &'static str {
1564 match self.adt_kind() {
1565 AdtKind::Struct => "struct",
1566 AdtKind::Union => "union",
1567 AdtKind::Enum => "variant",
1571 /// Returns whether this is a dtorck type. If this returns
1572 /// true, this type being safe for destruction requires it to be
1573 /// alive; Otherwise, only the contents are required to be.
1575 pub fn is_dtorck(&'gcx self, tcx: TyCtxt) -> bool {
1576 self.destructor(tcx).map_or(false, |d| d.is_dtorck)
1579 /// Returns whether this type is #[fundamental] for the purposes
1580 /// of coherence checking.
1582 pub fn is_fundamental(&self) -> bool {
1583 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
1586 /// Returns true if this is PhantomData<T>.
1588 pub fn is_phantom_data(&self) -> bool {
1589 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
1592 /// Returns true if this is Box<T>.
1594 pub fn is_box(&self) -> bool {
1595 self.flags.intersects(AdtFlags::IS_BOX)
1598 /// Returns whether this type has a destructor.
1599 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
1600 self.destructor(tcx).is_some()
1603 /// Asserts this is a struct and returns the struct's unique
1605 pub fn struct_variant(&self) -> &VariantDef {
1606 assert!(!self.is_enum());
1611 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
1612 tcx.item_predicates(self.did)
1615 /// Returns an iterator over all fields contained
1618 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
1619 self.variants.iter().flat_map(|v| v.fields.iter())
1623 pub fn is_univariant(&self) -> bool {
1624 self.variants.len() == 1
1627 pub fn is_payloadfree(&self) -> bool {
1628 !self.variants.is_empty() &&
1629 self.variants.iter().all(|v| v.fields.is_empty())
1632 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
1635 .find(|v| v.did == vid)
1636 .expect("variant_with_id: unknown variant")
1639 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1642 .position(|v| v.did == vid)
1643 .expect("variant_index_with_id: unknown variant")
1646 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
1648 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
1649 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
1650 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.struct_variant(),
1651 _ => bug!("unexpected def {:?} in variant_of_def", def)
1655 pub fn discriminants(&'a self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1656 -> impl Iterator<Item=ConstInt> + 'a {
1657 let repr_type = self.repr.discr_type();
1658 let initial = repr_type.initial_discriminant(tcx.global_tcx());
1659 let mut prev_discr = None::<ConstInt>;
1660 self.variants.iter().map(move |v| {
1661 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr());
1662 if let VariantDiscr::Explicit(expr_did) = v.discr {
1663 match tcx.maps.monomorphic_const_eval.borrow()[&expr_did] {
1664 Ok(ConstVal::Integral(v)) => {
1670 prev_discr = Some(discr);
1676 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
1677 queries::adt_destructor::get(tcx, DUMMY_SP, self.did)
1680 /// Returns a simpler type such that `Self: Sized` if and only
1681 /// if that type is Sized, or `TyErr` if this type is recursive.
1683 /// HACK: instead of returning a list of types, this function can
1684 /// return a tuple. In that case, the result is Sized only if
1685 /// all elements of the tuple are Sized.
1687 /// This is generally the `struct_tail` if this is a struct, or a
1688 /// tuple of them if this is an enum.
1690 /// Oddly enough, checking that the sized-constraint is Sized is
1691 /// actually more expressive than checking all members:
1692 /// the Sized trait is inductive, so an associated type that references
1693 /// Self would prevent its containing ADT from being Sized.
1695 /// Due to normalization being eager, this applies even if
1696 /// the associated type is behind a pointer, e.g. issue #31299.
1697 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Ty<'tcx> {
1698 self.calculate_sized_constraint_inner(tcx.global_tcx(), &mut Vec::new())
1701 /// Calculates the Sized-constraint.
1703 /// As the Sized-constraint of enums can be a *set* of types,
1704 /// the Sized-constraint may need to be a set also. Because introducing
1705 /// a new type of IVar is currently a complex affair, the Sized-constraint
1708 /// In fact, there are only a few options for the constraint:
1709 /// - `bool`, if the type is always Sized
1710 /// - an obviously-unsized type
1711 /// - a type parameter or projection whose Sizedness can't be known
1712 /// - a tuple of type parameters or projections, if there are multiple
1714 /// - a TyError, if a type contained itself. The representability
1715 /// check should catch this case.
1716 fn calculate_sized_constraint_inner(&self,
1717 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1718 stack: &mut Vec<DefId>)
1721 if let Some(ty) = tcx.maps.adt_sized_constraint.borrow().get(&self.did) {
1725 // Follow the memoization pattern: push the computation of
1726 // DepNode::SizedConstraint as our current task.
1727 let _task = tcx.dep_graph.in_task(DepNode::SizedConstraint(self.did));
1729 if stack.contains(&self.did) {
1730 debug!("calculate_sized_constraint: {:?} is recursive", self);
1731 // This should be reported as an error by `check_representable`.
1733 // Consider the type as Sized in the meanwhile to avoid
1735 tcx.maps.adt_sized_constraint.borrow_mut().insert(self.did, tcx.types.err);
1736 return tcx.types.err;
1739 stack.push(self.did);
1742 self.variants.iter().flat_map(|v| {
1745 let ty = tcx.item_type(f.did);
1746 self.sized_constraint_for_ty(tcx, stack, ty)
1749 let self_ = stack.pop().unwrap();
1750 assert_eq!(self_, self.did);
1752 let ty = match tys.len() {
1753 _ if tys.references_error() => tcx.types.err,
1754 0 => tcx.types.bool,
1756 _ => tcx.intern_tup(&tys[..], false)
1759 let old = tcx.maps.adt_sized_constraint.borrow().get(&self.did).cloned();
1762 debug!("calculate_sized_constraint: {:?} recurred", self);
1763 assert_eq!(old_ty, tcx.types.err);
1767 debug!("calculate_sized_constraint: {:?} => {:?}", self, ty);
1768 tcx.maps.adt_sized_constraint.borrow_mut().insert(self.did, ty);
1774 fn sized_constraint_for_ty(&self,
1775 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1776 stack: &mut Vec<DefId>,
1779 let result = match ty.sty {
1780 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
1781 TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
1782 TyArray(..) | TyClosure(..) | TyNever => {
1786 TyStr | TyDynamic(..) | TySlice(_) | TyError => {
1787 // these are never sized - return the target type
1791 TyTuple(ref tys, _) => {
1794 Some(ty) => self.sized_constraint_for_ty(tcx, stack, ty)
1798 TyAdt(adt, substs) => {
1801 adt.calculate_sized_constraint_inner(tcx, stack)
1802 .subst(tcx, substs);
1803 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
1805 if let ty::TyTuple(ref tys, _) = adt_ty.sty {
1806 tys.iter().flat_map(|ty| {
1807 self.sized_constraint_for_ty(tcx, stack, ty)
1810 self.sized_constraint_for_ty(tcx, stack, adt_ty)
1814 TyProjection(..) | TyAnon(..) => {
1815 // must calculate explicitly.
1816 // FIXME: consider special-casing always-Sized projections
1821 // perf hack: if there is a `T: Sized` bound, then
1822 // we know that `T` is Sized and do not need to check
1825 let sized_trait = match tcx.lang_items.sized_trait() {
1827 _ => return vec![ty]
1829 let sized_predicate = Binder(TraitRef {
1830 def_id: sized_trait,
1831 substs: tcx.mk_substs_trait(ty, &[])
1833 let predicates = tcx.item_predicates(self.did).predicates;
1834 if predicates.into_iter().any(|p| p == sized_predicate) {
1842 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
1846 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
1851 impl<'a, 'gcx, 'tcx> VariantDef {
1853 pub fn find_field_named(&self,
1855 -> Option<&FieldDef> {
1856 self.fields.iter().find(|f| f.name == name)
1860 pub fn index_of_field_named(&self,
1863 self.fields.iter().position(|f| f.name == name)
1867 pub fn field_named(&self, name: ast::Name) -> &FieldDef {
1868 self.find_field_named(name).unwrap()
1872 impl<'a, 'gcx, 'tcx> FieldDef {
1873 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1874 tcx.item_type(self.did).subst(tcx, subst)
1878 /// Records the substitutions used to translate the polytype for an
1879 /// item into the monotype of an item reference.
1880 #[derive(Clone, RustcEncodable, RustcDecodable)]
1881 pub struct ItemSubsts<'tcx> {
1882 pub substs: &'tcx Substs<'tcx>,
1885 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1886 pub enum ClosureKind {
1887 // Warning: Ordering is significant here! The ordering is chosen
1888 // because the trait Fn is a subtrait of FnMut and so in turn, and
1889 // hence we order it so that Fn < FnMut < FnOnce.
1895 impl<'a, 'tcx> ClosureKind {
1896 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
1898 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
1899 ClosureKind::FnMut => {
1900 tcx.require_lang_item(FnMutTraitLangItem)
1902 ClosureKind::FnOnce => {
1903 tcx.require_lang_item(FnOnceTraitLangItem)
1908 /// True if this a type that impls this closure kind
1909 /// must also implement `other`.
1910 pub fn extends(self, other: ty::ClosureKind) -> bool {
1911 match (self, other) {
1912 (ClosureKind::Fn, ClosureKind::Fn) => true,
1913 (ClosureKind::Fn, ClosureKind::FnMut) => true,
1914 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
1915 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
1916 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
1917 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
1923 impl<'tcx> TyS<'tcx> {
1924 /// Iterator that walks `self` and any types reachable from
1925 /// `self`, in depth-first order. Note that just walks the types
1926 /// that appear in `self`, it does not descend into the fields of
1927 /// structs or variants. For example:
1930 /// isize => { isize }
1931 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
1932 /// [isize] => { [isize], isize }
1934 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
1935 TypeWalker::new(self)
1938 /// Iterator that walks the immediate children of `self`. Hence
1939 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
1940 /// (but not `i32`, like `walk`).
1941 pub fn walk_shallow(&'tcx self) -> AccIntoIter<walk::TypeWalkerArray<'tcx>> {
1942 walk::walk_shallow(self)
1945 /// Walks `ty` and any types appearing within `ty`, invoking the
1946 /// callback `f` on each type. If the callback returns false, then the
1947 /// children of the current type are ignored.
1949 /// Note: prefer `ty.walk()` where possible.
1950 pub fn maybe_walk<F>(&'tcx self, mut f: F)
1951 where F : FnMut(Ty<'tcx>) -> bool
1953 let mut walker = self.walk();
1954 while let Some(ty) = walker.next() {
1956 walker.skip_current_subtree();
1962 impl<'tcx> ItemSubsts<'tcx> {
1963 pub fn is_noop(&self) -> bool {
1964 self.substs.is_noop()
1968 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1969 pub enum LvaluePreference {
1974 impl LvaluePreference {
1975 pub fn from_mutbl(m: hir::Mutability) -> Self {
1977 hir::MutMutable => PreferMutLvalue,
1978 hir::MutImmutable => NoPreference,
1984 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
1986 hir::MutMutable => MutBorrow,
1987 hir::MutImmutable => ImmBorrow,
1991 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
1992 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
1993 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
1995 pub fn to_mutbl_lossy(self) -> hir::Mutability {
1997 MutBorrow => hir::MutMutable,
1998 ImmBorrow => hir::MutImmutable,
2000 // We have no type corresponding to a unique imm borrow, so
2001 // use `&mut`. It gives all the capabilities of an `&uniq`
2002 // and hence is a safe "over approximation".
2003 UniqueImmBorrow => hir::MutMutable,
2007 pub fn to_user_str(&self) -> &'static str {
2009 MutBorrow => "mutable",
2010 ImmBorrow => "immutable",
2011 UniqueImmBorrow => "uniquely immutable",
2016 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2017 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2018 self.item_tables(self.hir.body_owner_def_id(body))
2021 pub fn item_tables(self, def_id: DefId) -> &'gcx TypeckTables<'gcx> {
2022 queries::typeck_tables::get(self, DUMMY_SP, def_id)
2025 pub fn expr_span(self, id: NodeId) -> Span {
2026 match self.hir.find(id) {
2027 Some(hir_map::NodeExpr(e)) => {
2031 bug!("Node id {} is not an expr: {:?}", id, f);
2034 bug!("Node id {} is not present in the node map", id);
2039 pub fn local_var_name_str(self, id: NodeId) -> InternedString {
2040 match self.hir.find(id) {
2041 Some(hir_map::NodeLocal(pat)) => {
2043 hir::PatKind::Binding(_, _, ref path1, _) => path1.node.as_str(),
2045 bug!("Variable id {} maps to {:?}, not local", id, pat);
2049 r => bug!("Variable id {} maps to {:?}, not local", id, r),
2053 pub fn expr_is_lval(self, expr: &hir::Expr) -> bool {
2055 hir::ExprPath(hir::QPath::Resolved(_, ref path)) => {
2057 Def::Local(..) | Def::Upvar(..) | Def::Static(..) | Def::Err => true,
2062 hir::ExprType(ref e, _) => {
2063 self.expr_is_lval(e)
2066 hir::ExprUnary(hir::UnDeref, _) |
2067 hir::ExprField(..) |
2068 hir::ExprTupField(..) |
2069 hir::ExprIndex(..) => {
2073 // Partially qualified paths in expressions can only legally
2074 // refer to associated items which are always rvalues.
2075 hir::ExprPath(hir::QPath::TypeRelative(..)) |
2078 hir::ExprMethodCall(..) |
2079 hir::ExprStruct(..) |
2082 hir::ExprMatch(..) |
2083 hir::ExprClosure(..) |
2084 hir::ExprBlock(..) |
2085 hir::ExprRepeat(..) |
2086 hir::ExprArray(..) |
2087 hir::ExprBreak(..) |
2088 hir::ExprAgain(..) |
2090 hir::ExprWhile(..) |
2092 hir::ExprAssign(..) |
2093 hir::ExprInlineAsm(..) |
2094 hir::ExprAssignOp(..) |
2096 hir::ExprUnary(..) |
2098 hir::ExprAddrOf(..) |
2099 hir::ExprBinary(..) |
2100 hir::ExprCast(..) => {
2106 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2107 self.associated_items(id)
2108 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2112 pub fn trait_impl_polarity(self, id: DefId) -> hir::ImplPolarity {
2113 if let Some(id) = self.hir.as_local_node_id(id) {
2114 match self.hir.expect_item(id).node {
2115 hir::ItemImpl(_, polarity, ..) => polarity,
2116 ref item => bug!("trait_impl_polarity: {:?} not an impl", item)
2119 self.sess.cstore.impl_polarity(id)
2123 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2124 self.associated_items(did).any(|item| {
2125 item.relevant_for_never()
2129 pub fn coerce_unsized_info(self, did: DefId) -> adjustment::CoerceUnsizedInfo {
2130 queries::coerce_unsized_info::get(self, DUMMY_SP, did)
2133 pub fn associated_item(self, def_id: DefId) -> AssociatedItem {
2134 queries::associated_item::get(self, DUMMY_SP, def_id)
2137 fn associated_item_from_trait_item_ref(self,
2138 parent_def_id: DefId,
2139 trait_item_ref: &hir::TraitItemRef)
2141 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2142 let (kind, has_self) = match trait_item_ref.kind {
2143 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2144 hir::AssociatedItemKind::Method { has_self } => {
2145 (ty::AssociatedKind::Method, has_self)
2147 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2151 name: trait_item_ref.name,
2153 vis: Visibility::from_hir(&hir::Inherited, trait_item_ref.id.node_id, self),
2154 defaultness: trait_item_ref.defaultness,
2156 container: TraitContainer(parent_def_id),
2157 method_has_self_argument: has_self
2161 fn associated_item_from_impl_item_ref(self,
2162 parent_def_id: DefId,
2163 from_trait_impl: bool,
2164 impl_item_ref: &hir::ImplItemRef)
2166 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2167 let (kind, has_self) = match impl_item_ref.kind {
2168 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2169 hir::AssociatedItemKind::Method { has_self } => {
2170 (ty::AssociatedKind::Method, has_self)
2172 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2175 // Trait impl items are always public.
2176 let public = hir::Public;
2177 let vis = if from_trait_impl { &public } else { &impl_item_ref.vis };
2179 ty::AssociatedItem {
2180 name: impl_item_ref.name,
2182 vis: ty::Visibility::from_hir(vis, impl_item_ref.id.node_id, self),
2183 defaultness: impl_item_ref.defaultness,
2185 container: ImplContainer(parent_def_id),
2186 method_has_self_argument: has_self
2190 pub fn associated_item_def_ids(self, def_id: DefId) -> Rc<Vec<DefId>> {
2191 if !def_id.is_local() {
2192 return queries::associated_item_def_ids::get(self, DUMMY_SP, def_id);
2195 self.maps.associated_item_def_ids.memoize(def_id, || {
2196 let id = self.hir.as_local_node_id(def_id).unwrap();
2197 let item = self.hir.expect_item(id);
2198 let vec: Vec<_> = match item.node {
2199 hir::ItemTrait(.., ref trait_item_refs) => {
2200 trait_item_refs.iter()
2201 .map(|trait_item_ref| trait_item_ref.id)
2202 .map(|id| self.hir.local_def_id(id.node_id))
2205 hir::ItemImpl(.., ref impl_item_refs) => {
2206 impl_item_refs.iter()
2207 .map(|impl_item_ref| impl_item_ref.id)
2208 .map(|id| self.hir.local_def_id(id.node_id))
2211 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2217 #[inline] // FIXME(#35870) Avoid closures being unexported due to impl Trait.
2218 pub fn associated_items(self, def_id: DefId)
2219 -> impl Iterator<Item = ty::AssociatedItem> + 'a {
2220 let def_ids = self.associated_item_def_ids(def_id);
2221 (0..def_ids.len()).map(move |i| self.associated_item(def_ids[i]))
2224 /// Returns the trait-ref corresponding to a given impl, or None if it is
2225 /// an inherent impl.
2226 pub fn impl_trait_ref(self, id: DefId) -> Option<TraitRef<'gcx>> {
2227 queries::impl_trait_ref::get(self, DUMMY_SP, id)
2230 // Returns `ty::VariantDef` if `def` refers to a struct,
2231 // or variant or their constructors, panics otherwise.
2232 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2234 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2235 let enum_did = self.parent_def_id(did).unwrap();
2236 self.lookup_adt_def(enum_did).variant_with_id(did)
2238 Def::Struct(did) | Def::Union(did) => {
2239 self.lookup_adt_def(did).struct_variant()
2241 Def::StructCtor(ctor_did, ..) => {
2242 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2243 self.lookup_adt_def(did).struct_variant()
2245 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2249 pub fn def_key(self, id: DefId) -> hir_map::DefKey {
2251 self.hir.def_key(id)
2253 self.sess.cstore.def_key(id)
2257 /// Convert a `DefId` into its fully expanded `DefPath` (every
2258 /// `DefId` is really just an interned def-path).
2260 /// Note that if `id` is not local to this crate, the result will
2261 /// be a non-local `DefPath`.
2262 pub fn def_path(self, id: DefId) -> hir_map::DefPath {
2264 self.hir.def_path(id)
2266 self.sess.cstore.def_path(id)
2271 pub fn def_path_hash(self, def_id: DefId) -> u64 {
2272 if def_id.is_local() {
2273 self.hir.definitions().def_path_hash(def_id.index)
2275 self.sess.cstore.def_path_hash(def_id)
2279 pub fn def_span(self, def_id: DefId) -> Span {
2280 if let Some(id) = self.hir.as_local_node_id(def_id) {
2283 self.sess.cstore.def_span(&self.sess, def_id)
2287 pub fn vis_is_accessible_from(self, vis: Visibility, block: NodeId) -> bool {
2288 vis.is_accessible_from(self.hir.local_def_id(self.hir.get_module_parent(block)), self)
2291 pub fn item_name(self, id: DefId) -> ast::Name {
2292 if let Some(id) = self.hir.as_local_node_id(id) {
2294 } else if id.index == CRATE_DEF_INDEX {
2295 self.sess.cstore.original_crate_name(id.krate)
2297 let def_key = self.sess.cstore.def_key(id);
2298 // The name of a StructCtor is that of its struct parent.
2299 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2300 self.item_name(DefId {
2302 index: def_key.parent.unwrap()
2305 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2306 bug!("item_name: no name for {:?}", self.def_path(id));
2312 // If the given item is in an external crate, looks up its type and adds it to
2313 // the type cache. Returns the type parameters and type.
2314 pub fn item_type(self, did: DefId) -> Ty<'gcx> {
2315 queries::ty::get(self, DUMMY_SP, did)
2318 /// Given the did of a trait, returns its canonical trait ref.
2319 pub fn lookup_trait_def(self, did: DefId) -> &'gcx TraitDef {
2320 queries::trait_def::get(self, DUMMY_SP, did)
2323 /// Given the did of an ADT, return a reference to its definition.
2324 pub fn lookup_adt_def(self, did: DefId) -> &'gcx AdtDef {
2325 queries::adt_def::get(self, DUMMY_SP, did)
2328 /// Given the did of an item, returns its generics.
2329 pub fn item_generics(self, did: DefId) -> &'gcx Generics {
2330 queries::generics::get(self, DUMMY_SP, did)
2333 /// Given the did of an item, returns its full set of predicates.
2334 pub fn item_predicates(self, did: DefId) -> GenericPredicates<'gcx> {
2335 queries::predicates::get(self, DUMMY_SP, did)
2338 /// Given the did of a trait, returns its superpredicates.
2339 pub fn item_super_predicates(self, did: DefId) -> GenericPredicates<'gcx> {
2340 queries::super_predicates::get(self, DUMMY_SP, did)
2343 /// Given the did of an item, returns its MIR, borrowed immutably.
2344 pub fn item_mir(self, did: DefId) -> Ref<'gcx, Mir<'gcx>> {
2345 queries::mir::get(self, DUMMY_SP, did).borrow()
2348 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2349 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2350 -> Ref<'gcx, Mir<'gcx>>
2353 ty::InstanceDef::Item(did) if true => self.item_mir(did),
2354 _ => queries::mir_shims::get(self, DUMMY_SP, instance).borrow(),
2358 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2359 /// Returns None if there is no MIR for the DefId
2360 pub fn maybe_item_mir(self, did: DefId) -> Option<Ref<'gcx, Mir<'gcx>>> {
2361 if did.is_local() && !self.maps.mir.borrow().contains_key(&did) {
2365 if !did.is_local() && !self.sess.cstore.is_item_mir_available(did) {
2369 Some(self.item_mir(did))
2372 /// If `type_needs_drop` returns true, then `ty` is definitely
2373 /// non-copy and *might* have a destructor attached; if it returns
2374 /// false, then `ty` definitely has no destructor (i.e. no drop glue).
2376 /// (Note that this implies that if `ty` has a destructor attached,
2377 /// then `type_needs_drop` will definitely return `true` for `ty`.)
2378 pub fn type_needs_drop_given_env(self,
2380 param_env: &ty::ParameterEnvironment<'gcx>) -> bool {
2381 // Issue #22536: We first query type_moves_by_default. It sees a
2382 // normalized version of the type, and therefore will definitely
2383 // know whether the type implements Copy (and thus needs no
2384 // cleanup/drop/zeroing) ...
2385 let tcx = self.global_tcx();
2386 let implements_copy = !ty.moves_by_default(tcx, param_env, DUMMY_SP);
2388 if implements_copy { return false; }
2390 // ... (issue #22536 continued) but as an optimization, still use
2391 // prior logic of asking if the `needs_drop` bit is set; we need
2392 // not zero non-Copy types if they have no destructor.
2394 // FIXME(#22815): Note that calling `ty::type_contents` is a
2395 // conservative heuristic; it may report that `needs_drop` is set
2396 // when actual type does not actually have a destructor associated
2397 // with it. But since `ty` absolutely did not have the `Copy`
2398 // bound attached (see above), it is sound to treat it as having a
2399 // destructor (e.g. zero its memory on move).
2401 let contents = ty.type_contents(tcx);
2402 debug!("type_needs_drop ty={:?} contents={:?}", ty, contents);
2403 contents.needs_drop(tcx)
2406 /// Get the attributes of a definition.
2407 pub fn get_attrs(self, did: DefId) -> Cow<'gcx, [ast::Attribute]> {
2408 if let Some(id) = self.hir.as_local_node_id(did) {
2409 Cow::Borrowed(self.hir.attrs(id))
2411 Cow::Owned(self.sess.cstore.item_attrs(did))
2415 /// Determine whether an item is annotated with an attribute
2416 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2417 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2420 pub fn item_variances(self, item_id: DefId) -> Rc<Vec<ty::Variance>> {
2421 queries::variances::get(self, DUMMY_SP, item_id)
2424 pub fn trait_has_default_impl(self, trait_def_id: DefId) -> bool {
2425 let def = self.lookup_trait_def(trait_def_id);
2426 def.flags.get().intersects(TraitFlags::HAS_DEFAULT_IMPL)
2429 /// Populates the type context with all the implementations for the given
2430 /// trait if necessary.
2431 pub fn populate_implementations_for_trait_if_necessary(self, trait_id: DefId) {
2432 if trait_id.is_local() {
2436 // The type is not local, hence we are reading this out of
2437 // metadata and don't need to track edges.
2438 let _ignore = self.dep_graph.in_ignore();
2440 let def = self.lookup_trait_def(trait_id);
2441 if def.flags.get().intersects(TraitFlags::HAS_REMOTE_IMPLS) {
2445 debug!("populate_implementations_for_trait_if_necessary: searching for {:?}", def);
2447 for impl_def_id in self.sess.cstore.implementations_of_trait(Some(trait_id)) {
2448 let trait_ref = self.impl_trait_ref(impl_def_id).unwrap();
2450 // Record the trait->implementation mapping.
2451 let parent = self.sess.cstore.impl_parent(impl_def_id).unwrap_or(trait_id);
2452 def.record_remote_impl(self, impl_def_id, trait_ref, parent);
2455 def.flags.set(def.flags.get() | TraitFlags::HAS_REMOTE_IMPLS);
2458 pub fn closure_kind(self, def_id: DefId) -> ty::ClosureKind {
2459 queries::closure_kind::get(self, DUMMY_SP, def_id)
2462 pub fn closure_type(self, def_id: DefId) -> ty::PolyFnSig<'tcx> {
2463 queries::closure_type::get(self, DUMMY_SP, def_id)
2466 /// Given the def_id of an impl, return the def_id of the trait it implements.
2467 /// If it implements no trait, return `None`.
2468 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2469 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2472 /// If the given def ID describes a method belonging to an impl, return the
2473 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2474 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2475 let item = if def_id.krate != LOCAL_CRATE {
2476 if let Some(Def::Method(_)) = self.sess.cstore.describe_def(def_id) {
2477 Some(self.associated_item(def_id))
2482 self.maps.associated_item.borrow().get(&def_id).cloned()
2486 Some(trait_item) => {
2487 match trait_item.container {
2488 TraitContainer(_) => None,
2489 ImplContainer(def_id) => Some(def_id),
2496 /// If the given def ID describes an item belonging to a trait,
2497 /// return the ID of the trait that the trait item belongs to.
2498 /// Otherwise, return `None`.
2499 pub fn trait_of_item(self, def_id: DefId) -> Option<DefId> {
2500 if def_id.krate != LOCAL_CRATE {
2501 return self.sess.cstore.trait_of_item(def_id);
2503 match self.maps.associated_item.borrow().get(&def_id) {
2504 Some(associated_item) => {
2505 match associated_item.container {
2506 TraitContainer(def_id) => Some(def_id),
2507 ImplContainer(_) => None
2514 /// Construct a parameter environment suitable for static contexts or other contexts where there
2515 /// are no free type/lifetime parameters in scope.
2516 pub fn empty_parameter_environment(self) -> ParameterEnvironment<'tcx> {
2518 // for an empty parameter environment, there ARE no free
2519 // regions, so it shouldn't matter what we use for the free id
2520 let free_id_outlive = self.region_maps.node_extent(ast::DUMMY_NODE_ID);
2521 ty::ParameterEnvironment {
2522 free_substs: self.intern_substs(&[]),
2523 caller_bounds: Vec::new(),
2524 implicit_region_bound: self.mk_region(ty::ReEmpty),
2525 free_id_outlive: free_id_outlive,
2526 is_copy_cache: RefCell::new(FxHashMap()),
2527 is_sized_cache: RefCell::new(FxHashMap()),
2531 /// Constructs and returns a substitution that can be applied to move from
2532 /// the "outer" view of a type or method to the "inner" view.
2533 /// In general, this means converting from bound parameters to
2534 /// free parameters. Since we currently represent bound/free type
2535 /// parameters in the same way, this only has an effect on regions.
2536 pub fn construct_free_substs(self, def_id: DefId,
2537 free_id_outlive: CodeExtent)
2538 -> &'gcx Substs<'gcx> {
2540 let substs = Substs::for_item(self.global_tcx(), def_id, |def, _| {
2541 // map bound 'a => free 'a
2542 self.global_tcx().mk_region(ReFree(FreeRegion {
2543 scope: free_id_outlive,
2544 bound_region: def.to_bound_region()
2548 self.global_tcx().mk_param_from_def(def)
2551 debug!("construct_parameter_environment: {:?}", substs);
2555 /// See `ParameterEnvironment` struct def'n for details.
2556 /// If you were using `free_id: NodeId`, you might try `self.region_maps.item_extent(free_id)`
2557 /// for the `free_id_outlive` parameter. (But note that this is not always quite right.)
2558 pub fn construct_parameter_environment(self,
2561 free_id_outlive: CodeExtent)
2562 -> ParameterEnvironment<'gcx>
2565 // Construct the free substs.
2568 let free_substs = self.construct_free_substs(def_id, free_id_outlive);
2571 // Compute the bounds on Self and the type parameters.
2574 let tcx = self.global_tcx();
2575 let generic_predicates = tcx.item_predicates(def_id);
2576 let bounds = generic_predicates.instantiate(tcx, free_substs);
2577 let bounds = tcx.liberate_late_bound_regions(free_id_outlive, &ty::Binder(bounds));
2578 let predicates = bounds.predicates;
2580 // Finally, we have to normalize the bounds in the environment, in
2581 // case they contain any associated type projections. This process
2582 // can yield errors if the put in illegal associated types, like
2583 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2584 // report these errors right here; this doesn't actually feel
2585 // right to me, because constructing the environment feels like a
2586 // kind of a "idempotent" action, but I'm not sure where would be
2587 // a better place. In practice, we construct environments for
2588 // every fn once during type checking, and we'll abort if there
2589 // are any errors at that point, so after type checking you can be
2590 // sure that this will succeed without errors anyway.
2593 let unnormalized_env = ty::ParameterEnvironment {
2594 free_substs: free_substs,
2595 implicit_region_bound: tcx.mk_region(ty::ReScope(free_id_outlive)),
2596 caller_bounds: predicates,
2597 free_id_outlive: free_id_outlive,
2598 is_copy_cache: RefCell::new(FxHashMap()),
2599 is_sized_cache: RefCell::new(FxHashMap()),
2602 let cause = traits::ObligationCause::misc(span, free_id_outlive.node_id(&self.region_maps));
2603 traits::normalize_param_env_or_error(tcx, unnormalized_env, cause)
2606 pub fn node_scope_region(self, id: NodeId) -> &'tcx Region {
2607 self.mk_region(ty::ReScope(self.region_maps.node_extent(id)))
2610 pub fn visit_all_item_likes_in_krate<V,F>(self,
2613 where F: FnMut(DefId) -> DepNode<DefId>, V: ItemLikeVisitor<'gcx>
2615 dep_graph::visit_all_item_likes_in_krate(self.global_tcx(), dep_node_fn, visitor);
2618 /// Invokes `callback` for each body in the krate. This will
2619 /// create a read edge from `DepNode::Krate` to the current task;
2620 /// it is meant to be run in the context of some global task like
2621 /// `BorrowckCrate`. The callback would then create a task like
2622 /// `BorrowckBody(DefId)` to process each individual item.
2623 pub fn visit_all_bodies_in_krate<C>(self, callback: C)
2624 where C: Fn(/* body_owner */ DefId, /* body id */ hir::BodyId),
2626 dep_graph::visit_all_bodies_in_krate(self.global_tcx(), callback)
2629 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2630 /// with the name of the crate containing the impl.
2631 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2632 if impl_did.is_local() {
2633 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2634 Ok(self.hir.span(node_id))
2636 Err(self.sess.cstore.crate_name(impl_did.krate))
2641 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2642 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2643 F: FnOnce(&[hir::Freevar]) -> T,
2645 match self.freevars.borrow().get(&fid) {
2647 Some(d) => f(&d[..])
2652 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
2655 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2656 let parent_id = tcx.hir.get_parent(id);
2657 let parent_def_id = tcx.hir.local_def_id(parent_id);
2658 let parent_item = tcx.hir.expect_item(parent_id);
2659 match parent_item.node {
2660 hir::ItemImpl(.., ref impl_trait_ref, _, ref impl_item_refs) => {
2661 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2663 tcx.associated_item_from_impl_item_ref(parent_def_id,
2664 impl_trait_ref.is_some(),
2666 debug_assert_eq!(assoc_item.def_id, def_id);
2671 hir::ItemTrait(.., ref trait_item_refs) => {
2672 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2674 tcx.associated_item_from_trait_item_ref(parent_def_id, trait_item_ref);
2675 debug_assert_eq!(assoc_item.def_id, def_id);
2681 panic!("unexpected container of associated items: {:?}", r)
2684 panic!("associated item not found for def_id: {:?}", def_id);
2687 pub fn provide(providers: &mut ty::maps::Providers) {
2688 *providers = ty::maps::Providers {
2695 /// A map for the local crate mapping each type to a vector of its
2696 /// inherent impls. This is not meant to be used outside of coherence;
2697 /// rather, you should request the vector for a specific type via
2698 /// `ty::queries::inherent_impls::get(def_id)` so as to minimize your
2699 /// dependencies (constructing this map requires touching the entire
2701 #[derive(Clone, Debug)]
2702 pub struct CrateInherentImpls {
2703 pub inherent_impls: DefIdMap<Rc<Vec<DefId>>>,