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;
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::ErrorReported;
35 use util::nodemap::{NodeSet, DefIdMap, FxHashMap, FxHashSet};
37 use serialize::{self, Encodable, Encoder};
38 use std::cell::{Cell, RefCell, Ref};
39 use std::collections::BTreeMap;
42 use std::hash::{Hash, Hasher};
43 use std::iter::FromIterator;
47 use std::vec::IntoIter;
49 use syntax::ast::{self, DUMMY_NODE_ID, Name, NodeId};
51 use syntax::symbol::{Symbol, InternedString};
52 use syntax_pos::{DUMMY_SP, Span};
53 use rustc_const_math::ConstInt;
55 use rustc_data_structures::accumulate_vec::IntoIter as AccIntoIter;
56 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
60 use hir::itemlikevisit::ItemLikeVisitor;
62 pub use self::sty::{Binder, DebruijnIndex};
63 pub use self::sty::{FnSig, PolyFnSig};
64 pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
65 pub use self::sty::{ClosureSubsts, TypeAndMut};
66 pub use self::sty::{TraitRef, TypeVariants, PolyTraitRef};
67 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
68 pub use self::sty::{ExistentialProjection, PolyExistentialProjection};
69 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
70 pub use self::sty::RegionKind;
71 pub use self::sty::Issue32330;
72 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid, SkolemizedRegionVid};
73 pub use self::sty::BoundRegion::*;
74 pub use self::sty::InferTy::*;
75 pub use self::sty::RegionKind::*;
76 pub use self::sty::TypeVariants::*;
78 pub use self::context::{TyCtxt, GlobalArenas, tls};
79 pub use self::context::{Lift, TypeckTables};
81 pub use self::instance::{Instance, InstanceDef};
83 pub use self::trait_def::{TraitDef, TraitFlags};
85 pub use self::maps::queries;
92 pub mod inhabitedness;
108 mod structural_impls;
113 /// The complete set of all analyses described in this module. This is
114 /// produced by the driver and fed to trans and later passes.
116 /// NB: These contents are being migrated into queries using the
117 /// *on-demand* infrastructure.
119 pub struct CrateAnalysis {
120 pub access_levels: Rc<AccessLevels>,
121 pub reachable: Rc<NodeSet>,
123 pub glob_map: Option<hir::GlobMap>,
127 pub struct Resolutions {
128 pub freevars: FreevarMap,
129 pub trait_map: TraitMap,
130 pub maybe_unused_trait_imports: NodeSet,
131 pub export_map: ExportMap,
134 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
135 pub enum AssociatedItemContainer {
136 TraitContainer(DefId),
137 ImplContainer(DefId),
140 impl AssociatedItemContainer {
141 pub fn id(&self) -> DefId {
143 TraitContainer(id) => id,
144 ImplContainer(id) => id,
149 /// The "header" of an impl is everything outside the body: a Self type, a trait
150 /// ref (in the case of a trait impl), and a set of predicates (from the
151 /// bounds/where clauses).
152 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
153 pub struct ImplHeader<'tcx> {
154 pub impl_def_id: DefId,
155 pub self_ty: Ty<'tcx>,
156 pub trait_ref: Option<TraitRef<'tcx>>,
157 pub predicates: Vec<Predicate<'tcx>>,
160 impl<'a, 'gcx, 'tcx> ImplHeader<'tcx> {
161 pub fn with_fresh_ty_vars(selcx: &mut traits::SelectionContext<'a, 'gcx, 'tcx>,
165 let tcx = selcx.tcx();
166 let impl_substs = selcx.infcx().fresh_substs_for_item(DUMMY_SP, impl_def_id);
168 let header = ImplHeader {
169 impl_def_id: impl_def_id,
170 self_ty: tcx.type_of(impl_def_id),
171 trait_ref: tcx.impl_trait_ref(impl_def_id),
172 predicates: tcx.predicates_of(impl_def_id).predicates
173 }.subst(tcx, impl_substs);
175 let traits::Normalized { value: mut header, obligations } =
176 traits::normalize(selcx, traits::ObligationCause::dummy(), &header);
178 header.predicates.extend(obligations.into_iter().map(|o| o.predicate));
183 #[derive(Copy, Clone, Debug)]
184 pub struct AssociatedItem {
187 pub kind: AssociatedKind,
189 pub defaultness: hir::Defaultness,
190 pub container: AssociatedItemContainer,
192 /// Whether this is a method with an explicit self
193 /// as its first argument, allowing method calls.
194 pub method_has_self_argument: bool,
197 #[derive(Copy, Clone, PartialEq, Eq, Debug, RustcEncodable, RustcDecodable)]
198 pub enum AssociatedKind {
204 impl AssociatedItem {
205 pub fn def(&self) -> Def {
207 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
208 AssociatedKind::Method => Def::Method(self.def_id),
209 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
213 /// Tests whether the associated item admits a non-trivial implementation
215 pub fn relevant_for_never<'tcx>(&self) -> bool {
217 AssociatedKind::Const => true,
218 AssociatedKind::Type => true,
219 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
220 AssociatedKind::Method => !self.method_has_self_argument,
225 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
226 pub enum Visibility {
227 /// Visible everywhere (including in other crates).
229 /// Visible only in the given crate-local module.
231 /// Not visible anywhere in the local crate. This is the visibility of private external items.
235 pub trait DefIdTree: Copy {
236 fn parent(self, id: DefId) -> Option<DefId>;
238 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
239 if descendant.krate != ancestor.krate {
243 while descendant != ancestor {
244 match self.parent(descendant) {
245 Some(parent) => descendant = parent,
246 None => return false,
253 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
254 fn parent(self, id: DefId) -> Option<DefId> {
255 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
260 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt) -> Self {
262 hir::Public => Visibility::Public,
263 hir::Visibility::Crate => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
264 hir::Visibility::Restricted { ref path, .. } => match path.def {
265 // If there is no resolution, `resolve` will have already reported an error, so
266 // assume that the visibility is public to avoid reporting more privacy errors.
267 Def::Err => Visibility::Public,
268 def => Visibility::Restricted(def.def_id()),
271 Visibility::Restricted(tcx.hir.local_def_id(tcx.hir.get_module_parent(id)))
276 /// Returns true if an item with this visibility is accessible from the given block.
277 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
278 let restriction = match self {
279 // Public items are visible everywhere.
280 Visibility::Public => return true,
281 // Private items from other crates are visible nowhere.
282 Visibility::Invisible => return false,
283 // Restricted items are visible in an arbitrary local module.
284 Visibility::Restricted(other) if other.krate != module.krate => return false,
285 Visibility::Restricted(module) => module,
288 tree.is_descendant_of(module, restriction)
291 /// Returns true if this visibility is at least as accessible as the given visibility
292 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
293 let vis_restriction = match vis {
294 Visibility::Public => return self == Visibility::Public,
295 Visibility::Invisible => return true,
296 Visibility::Restricted(module) => module,
299 self.is_accessible_from(vis_restriction, tree)
303 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
305 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
306 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
307 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
308 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
311 #[derive(Clone, Copy, Debug, RustcDecodable, RustcEncodable)]
312 pub struct MethodCallee<'tcx> {
313 /// Impl method ID, for inherent methods, or trait method ID, otherwise.
316 pub substs: &'tcx Substs<'tcx>
319 /// With method calls, we store some extra information in
320 /// side tables (i.e method_map). We use
321 /// MethodCall as a key to index into these tables instead of
322 /// just directly using the expression's NodeId. The reason
323 /// for this being that we may apply adjustments (coercions)
324 /// with the resulting expression also needing to use the
325 /// side tables. The problem with this is that we don't
326 /// assign a separate NodeId to this new expression
327 /// and so it would clash with the base expression if both
328 /// needed to add to the side tables. Thus to disambiguate
329 /// we also keep track of whether there's an adjustment in
331 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
332 pub struct MethodCall {
338 pub fn expr(id: NodeId) -> MethodCall {
345 pub fn autoderef(expr_id: NodeId, autoderef: u32) -> MethodCall {
348 autoderef: 1 + autoderef
353 // maps from an expression id that corresponds to a method call to the details
354 // of the method to be invoked
355 pub type MethodMap<'tcx> = FxHashMap<MethodCall, MethodCallee<'tcx>>;
357 // Contains information needed to resolve types and (in the future) look up
358 // the types of AST nodes.
359 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
360 pub struct CReaderCacheKey {
365 /// Describes the fragment-state associated with a NodeId.
367 /// Currently only unfragmented paths have entries in the table,
368 /// but longer-term this enum is expected to expand to also
369 /// include data for fragmented paths.
370 #[derive(Copy, Clone, Debug)]
371 pub enum FragmentInfo {
372 Moved { var: NodeId, move_expr: NodeId },
373 Assigned { var: NodeId, assign_expr: NodeId, assignee_id: NodeId },
376 // Flags that we track on types. These flags are propagated upwards
377 // through the type during type construction, so that we can quickly
378 // check whether the type has various kinds of types in it without
379 // recursing over the type itself.
381 flags TypeFlags: u32 {
382 const HAS_PARAMS = 1 << 0,
383 const HAS_SELF = 1 << 1,
384 const HAS_TY_INFER = 1 << 2,
385 const HAS_RE_INFER = 1 << 3,
386 const HAS_RE_SKOL = 1 << 4,
387 const HAS_RE_EARLY_BOUND = 1 << 5,
388 const HAS_FREE_REGIONS = 1 << 6,
389 const HAS_TY_ERR = 1 << 7,
390 const HAS_PROJECTION = 1 << 8,
391 const HAS_TY_CLOSURE = 1 << 9,
393 // true if there are "names" of types and regions and so forth
394 // that are local to a particular fn
395 const HAS_LOCAL_NAMES = 1 << 10,
397 // Present if the type belongs in a local type context.
398 // Only set for TyInfer other than Fresh.
399 const KEEP_IN_LOCAL_TCX = 1 << 11,
401 // Is there a projection that does not involve a bound region?
402 // Currently we can't normalize projections w/ bound regions.
403 const HAS_NORMALIZABLE_PROJECTION = 1 << 12,
405 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
406 TypeFlags::HAS_SELF.bits |
407 TypeFlags::HAS_RE_EARLY_BOUND.bits,
409 // Flags representing the nominal content of a type,
410 // computed by FlagsComputation. If you add a new nominal
411 // flag, it should be added here too.
412 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
413 TypeFlags::HAS_SELF.bits |
414 TypeFlags::HAS_TY_INFER.bits |
415 TypeFlags::HAS_RE_INFER.bits |
416 TypeFlags::HAS_RE_SKOL.bits |
417 TypeFlags::HAS_RE_EARLY_BOUND.bits |
418 TypeFlags::HAS_FREE_REGIONS.bits |
419 TypeFlags::HAS_TY_ERR.bits |
420 TypeFlags::HAS_PROJECTION.bits |
421 TypeFlags::HAS_TY_CLOSURE.bits |
422 TypeFlags::HAS_LOCAL_NAMES.bits |
423 TypeFlags::KEEP_IN_LOCAL_TCX.bits,
425 // Caches for type_is_sized, type_moves_by_default
426 const SIZEDNESS_CACHED = 1 << 16,
427 const IS_SIZED = 1 << 17,
428 const MOVENESS_CACHED = 1 << 18,
429 const MOVES_BY_DEFAULT = 1 << 19,
430 const FREEZENESS_CACHED = 1 << 20,
431 const IS_FREEZE = 1 << 21,
432 const NEEDS_DROP_CACHED = 1 << 22,
433 const NEEDS_DROP = 1 << 23,
437 pub struct TyS<'tcx> {
438 pub sty: TypeVariants<'tcx>,
439 pub flags: Cell<TypeFlags>,
441 // the maximal depth of any bound regions appearing in this type.
445 impl<'tcx> PartialEq for TyS<'tcx> {
447 fn eq(&self, other: &TyS<'tcx>) -> bool {
448 // (self as *const _) == (other as *const _)
449 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
452 impl<'tcx> Eq for TyS<'tcx> {}
454 impl<'tcx> Hash for TyS<'tcx> {
455 fn hash<H: Hasher>(&self, s: &mut H) {
456 (self as *const TyS).hash(s)
460 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for ty::TyS<'tcx> {
461 fn hash_stable<W: StableHasherResult>(&self,
462 hcx: &mut StableHashingContext<'a, 'tcx>,
463 hasher: &mut StableHasher<W>) {
467 // The other fields just provide fast access to information that is
468 // also contained in `sty`, so no need to hash them.
473 sty.hash_stable(hcx, hasher);
477 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
479 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
480 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
482 /// A wrapper for slices with the additional invariant
483 /// that the slice is interned and no other slice with
484 /// the same contents can exist in the same context.
485 /// This means we can use pointer + length for both
486 /// equality comparisons and hashing.
487 #[derive(Debug, RustcEncodable)]
488 pub struct Slice<T>([T]);
490 impl<T> PartialEq for Slice<T> {
492 fn eq(&self, other: &Slice<T>) -> bool {
493 (&self.0 as *const [T]) == (&other.0 as *const [T])
496 impl<T> Eq for Slice<T> {}
498 impl<T> Hash for Slice<T> {
499 fn hash<H: Hasher>(&self, s: &mut H) {
500 (self.as_ptr(), self.len()).hash(s)
504 impl<T> Deref for Slice<T> {
506 fn deref(&self) -> &[T] {
511 impl<'a, T> IntoIterator for &'a Slice<T> {
513 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
514 fn into_iter(self) -> Self::IntoIter {
519 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {}
522 pub fn empty<'a>() -> &'a Slice<T> {
524 mem::transmute(slice::from_raw_parts(0x1 as *const T, 0))
529 /// Upvars do not get their own node-id. Instead, we use the pair of
530 /// the original var id (that is, the root variable that is referenced
531 /// by the upvar) and the id of the closure expression.
532 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
535 pub closure_expr_id: NodeId,
538 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
539 pub enum BorrowKind {
540 /// Data must be immutable and is aliasable.
543 /// Data must be immutable but not aliasable. This kind of borrow
544 /// cannot currently be expressed by the user and is used only in
545 /// implicit closure bindings. It is needed when the closure
546 /// is borrowing or mutating a mutable referent, e.g.:
548 /// let x: &mut isize = ...;
549 /// let y = || *x += 5;
551 /// If we were to try to translate this closure into a more explicit
552 /// form, we'd encounter an error with the code as written:
554 /// struct Env { x: & &mut isize }
555 /// let x: &mut isize = ...;
556 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
557 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
559 /// This is then illegal because you cannot mutate a `&mut` found
560 /// in an aliasable location. To solve, you'd have to translate with
561 /// an `&mut` borrow:
563 /// struct Env { x: & &mut isize }
564 /// let x: &mut isize = ...;
565 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
566 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
568 /// Now the assignment to `**env.x` is legal, but creating a
569 /// mutable pointer to `x` is not because `x` is not mutable. We
570 /// could fix this by declaring `x` as `let mut x`. This is ok in
571 /// user code, if awkward, but extra weird for closures, since the
572 /// borrow is hidden.
574 /// So we introduce a "unique imm" borrow -- the referent is
575 /// immutable, but not aliasable. This solves the problem. For
576 /// simplicity, we don't give users the way to express this
577 /// borrow, it's just used when translating closures.
580 /// Data is mutable and not aliasable.
584 /// Information describing the capture of an upvar. This is computed
585 /// during `typeck`, specifically by `regionck`.
586 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
587 pub enum UpvarCapture<'tcx> {
588 /// Upvar is captured by value. This is always true when the
589 /// closure is labeled `move`, but can also be true in other cases
590 /// depending on inference.
593 /// Upvar is captured by reference.
594 ByRef(UpvarBorrow<'tcx>),
597 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
598 pub struct UpvarBorrow<'tcx> {
599 /// The kind of borrow: by-ref upvars have access to shared
600 /// immutable borrows, which are not part of the normal language
602 pub kind: BorrowKind,
604 /// Region of the resulting reference.
605 pub region: ty::Region<'tcx>,
608 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
610 #[derive(Copy, Clone)]
611 pub struct ClosureUpvar<'tcx> {
617 #[derive(Clone, Copy, PartialEq)]
618 pub enum IntVarValue {
620 UintType(ast::UintTy),
623 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
624 pub struct TypeParameterDef {
628 pub has_default: bool,
629 pub object_lifetime_default: ObjectLifetimeDefault,
631 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
632 /// on generic parameter `T`, asserts data behind the parameter
633 /// `T` won't be accessed during the parent type's `Drop` impl.
634 pub pure_wrt_drop: bool,
637 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
638 pub struct RegionParameterDef {
642 pub issue_32330: Option<ty::Issue32330>,
644 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
645 /// on generic parameter `'a`, asserts data of lifetime `'a`
646 /// won't be accessed during the parent type's `Drop` impl.
647 pub pure_wrt_drop: bool,
650 impl RegionParameterDef {
651 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
652 ty::EarlyBoundRegion {
658 pub fn to_bound_region(&self) -> ty::BoundRegion {
659 ty::BoundRegion::BrNamed(self.def_id, self.name)
663 /// Information about the formal type/lifetime parameters associated
664 /// with an item or method. Analogous to hir::Generics.
665 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
666 pub struct Generics {
667 pub parent: Option<DefId>,
668 pub parent_regions: u32,
669 pub parent_types: u32,
670 pub regions: Vec<RegionParameterDef>,
671 pub types: Vec<TypeParameterDef>,
673 /// Reverse map to each `TypeParameterDef`'s `index` field, from
674 /// `def_id.index` (`def_id.krate` is the same as the item's).
675 pub type_param_to_index: BTreeMap<DefIndex, u32>,
681 pub fn parent_count(&self) -> usize {
682 self.parent_regions as usize + self.parent_types as usize
685 pub fn own_count(&self) -> usize {
686 self.regions.len() + self.types.len()
689 pub fn count(&self) -> usize {
690 self.parent_count() + self.own_count()
693 pub fn region_param(&self, param: &EarlyBoundRegion) -> &RegionParameterDef {
694 assert_eq!(self.parent_count(), 0);
695 &self.regions[param.index as usize - self.has_self as usize]
698 pub fn type_param(&self, param: &ParamTy) -> &TypeParameterDef {
699 assert_eq!(self.parent_count(), 0);
700 &self.types[param.idx as usize - self.has_self as usize - self.regions.len()]
704 /// Bounds on generics.
705 #[derive(Clone, Default)]
706 pub struct GenericPredicates<'tcx> {
707 pub parent: Option<DefId>,
708 pub predicates: Vec<Predicate<'tcx>>,
711 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
712 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
714 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
715 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
716 -> InstantiatedPredicates<'tcx> {
717 let mut instantiated = InstantiatedPredicates::empty();
718 self.instantiate_into(tcx, &mut instantiated, substs);
721 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
722 -> InstantiatedPredicates<'tcx> {
723 InstantiatedPredicates {
724 predicates: self.predicates.subst(tcx, substs)
728 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
729 instantiated: &mut InstantiatedPredicates<'tcx>,
730 substs: &Substs<'tcx>) {
731 if let Some(def_id) = self.parent {
732 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
734 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
737 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
738 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
739 -> InstantiatedPredicates<'tcx>
741 assert_eq!(self.parent, None);
742 InstantiatedPredicates {
743 predicates: self.predicates.iter().map(|pred| {
744 pred.subst_supertrait(tcx, poly_trait_ref)
750 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
751 pub enum Predicate<'tcx> {
752 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
753 /// the `Self` type of the trait reference and `A`, `B`, and `C`
754 /// would be the type parameters.
755 Trait(PolyTraitPredicate<'tcx>),
757 /// where `T1 == T2`.
758 Equate(PolyEquatePredicate<'tcx>),
761 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
764 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
766 /// where <T as TraitRef>::Name == X, approximately.
767 /// See `ProjectionPredicate` struct for details.
768 Projection(PolyProjectionPredicate<'tcx>),
771 WellFormed(Ty<'tcx>),
773 /// trait must be object-safe
776 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
777 /// for some substitutions `...` and T being a closure type.
778 /// Satisfied (or refuted) once we know the closure's kind.
779 ClosureKind(DefId, ClosureKind),
782 Subtype(PolySubtypePredicate<'tcx>),
785 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
786 /// Performs a substitution suitable for going from a
787 /// poly-trait-ref to supertraits that must hold if that
788 /// poly-trait-ref holds. This is slightly different from a normal
789 /// substitution in terms of what happens with bound regions. See
790 /// lengthy comment below for details.
791 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
792 trait_ref: &ty::PolyTraitRef<'tcx>)
793 -> ty::Predicate<'tcx>
795 // The interaction between HRTB and supertraits is not entirely
796 // obvious. Let me walk you (and myself) through an example.
798 // Let's start with an easy case. Consider two traits:
800 // trait Foo<'a> : Bar<'a,'a> { }
801 // trait Bar<'b,'c> { }
803 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
804 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
805 // knew that `Foo<'x>` (for any 'x) then we also know that
806 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
807 // normal substitution.
809 // In terms of why this is sound, the idea is that whenever there
810 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
811 // holds. So if there is an impl of `T:Foo<'a>` that applies to
812 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
815 // Another example to be careful of is this:
817 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
818 // trait Bar1<'b,'c> { }
820 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
821 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
822 // reason is similar to the previous example: any impl of
823 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
824 // basically we would want to collapse the bound lifetimes from
825 // the input (`trait_ref`) and the supertraits.
827 // To achieve this in practice is fairly straightforward. Let's
828 // consider the more complicated scenario:
830 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
831 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
832 // where both `'x` and `'b` would have a DB index of 1.
833 // The substitution from the input trait-ref is therefore going to be
834 // `'a => 'x` (where `'x` has a DB index of 1).
835 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
836 // early-bound parameter and `'b' is a late-bound parameter with a
838 // - If we replace `'a` with `'x` from the input, it too will have
839 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
840 // just as we wanted.
842 // There is only one catch. If we just apply the substitution `'a
843 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
844 // adjust the DB index because we substituting into a binder (it
845 // tries to be so smart...) resulting in `for<'x> for<'b>
846 // Bar1<'x,'b>` (we have no syntax for this, so use your
847 // imagination). Basically the 'x will have DB index of 2 and 'b
848 // will have DB index of 1. Not quite what we want. So we apply
849 // the substitution to the *contents* of the trait reference,
850 // rather than the trait reference itself (put another way, the
851 // substitution code expects equal binding levels in the values
852 // from the substitution and the value being substituted into, and
853 // this trick achieves that).
855 let substs = &trait_ref.0.substs;
857 Predicate::Trait(ty::Binder(ref data)) =>
858 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
859 Predicate::Equate(ty::Binder(ref data)) =>
860 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
861 Predicate::Subtype(ty::Binder(ref data)) =>
862 Predicate::Subtype(ty::Binder(data.subst(tcx, substs))),
863 Predicate::RegionOutlives(ty::Binder(ref data)) =>
864 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
865 Predicate::TypeOutlives(ty::Binder(ref data)) =>
866 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
867 Predicate::Projection(ty::Binder(ref data)) =>
868 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
869 Predicate::WellFormed(data) =>
870 Predicate::WellFormed(data.subst(tcx, substs)),
871 Predicate::ObjectSafe(trait_def_id) =>
872 Predicate::ObjectSafe(trait_def_id),
873 Predicate::ClosureKind(closure_def_id, kind) =>
874 Predicate::ClosureKind(closure_def_id, kind),
879 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
880 pub struct TraitPredicate<'tcx> {
881 pub trait_ref: TraitRef<'tcx>
883 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
885 impl<'tcx> TraitPredicate<'tcx> {
886 pub fn def_id(&self) -> DefId {
887 self.trait_ref.def_id
890 /// Creates the dep-node for selecting/evaluating this trait reference.
891 fn dep_node(&self) -> DepNode<DefId> {
892 // Extact the trait-def and first def-id from inputs. See the
893 // docs for `DepNode::TraitSelect` for more information.
894 let trait_def_id = self.def_id();
897 .flat_map(|t| t.walk())
898 .filter_map(|t| match t.sty {
899 ty::TyAdt(adt_def, _) => Some(adt_def.did),
903 .unwrap_or(trait_def_id);
904 DepNode::TraitSelect {
905 trait_def_id: trait_def_id,
906 input_def_id: input_def_id
910 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
911 self.trait_ref.input_types()
914 pub fn self_ty(&self) -> Ty<'tcx> {
915 self.trait_ref.self_ty()
919 impl<'tcx> PolyTraitPredicate<'tcx> {
920 pub fn def_id(&self) -> DefId {
921 // ok to skip binder since trait def-id does not care about regions
925 pub fn dep_node(&self) -> DepNode<DefId> {
926 // ok to skip binder since depnode does not care about regions
931 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
932 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
933 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
935 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
936 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
937 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
938 pub type PolyRegionOutlivesPredicate<'tcx> = PolyOutlivesPredicate<ty::Region<'tcx>,
940 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
942 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
943 pub struct SubtypePredicate<'tcx> {
944 pub a_is_expected: bool,
948 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
950 /// This kind of predicate has no *direct* correspondent in the
951 /// syntax, but it roughly corresponds to the syntactic forms:
953 /// 1. `T : TraitRef<..., Item=Type>`
954 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
956 /// In particular, form #1 is "desugared" to the combination of a
957 /// normal trait predicate (`T : TraitRef<...>`) and one of these
958 /// predicates. Form #2 is a broader form in that it also permits
959 /// equality between arbitrary types. Processing an instance of Form
960 /// #2 eventually yields one of these `ProjectionPredicate`
961 /// instances to normalize the LHS.
962 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
963 pub struct ProjectionPredicate<'tcx> {
964 pub projection_ty: ProjectionTy<'tcx>,
968 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
970 impl<'tcx> PolyProjectionPredicate<'tcx> {
971 pub fn item_name(&self) -> Name {
972 self.0.projection_ty.item_name // safe to skip the binder to access a name
976 pub trait ToPolyTraitRef<'tcx> {
977 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
980 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
981 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
982 assert!(!self.has_escaping_regions());
983 ty::Binder(self.clone())
987 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
988 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
989 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
993 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
994 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
995 // Note: unlike with TraitRef::to_poly_trait_ref(),
996 // self.0.trait_ref is permitted to have escaping regions.
997 // This is because here `self` has a `Binder` and so does our
998 // return value, so we are preserving the number of binding
1000 ty::Binder(self.0.projection_ty.trait_ref)
1004 pub trait ToPredicate<'tcx> {
1005 fn to_predicate(&self) -> Predicate<'tcx>;
1008 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1009 fn to_predicate(&self) -> Predicate<'tcx> {
1010 // we're about to add a binder, so let's check that we don't
1011 // accidentally capture anything, or else that might be some
1012 // weird debruijn accounting.
1013 assert!(!self.has_escaping_regions());
1015 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
1016 trait_ref: self.clone()
1021 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1022 fn to_predicate(&self) -> Predicate<'tcx> {
1023 ty::Predicate::Trait(self.to_poly_trait_predicate())
1027 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
1028 fn to_predicate(&self) -> Predicate<'tcx> {
1029 Predicate::Equate(self.clone())
1033 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1034 fn to_predicate(&self) -> Predicate<'tcx> {
1035 Predicate::RegionOutlives(self.clone())
1039 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1040 fn to_predicate(&self) -> Predicate<'tcx> {
1041 Predicate::TypeOutlives(self.clone())
1045 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1046 fn to_predicate(&self) -> Predicate<'tcx> {
1047 Predicate::Projection(self.clone())
1051 impl<'tcx> Predicate<'tcx> {
1052 /// Iterates over the types in this predicate. Note that in all
1053 /// cases this is skipping over a binder, so late-bound regions
1054 /// with depth 0 are bound by the predicate.
1055 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1056 let vec: Vec<_> = match *self {
1057 ty::Predicate::Trait(ref data) => {
1058 data.skip_binder().input_types().collect()
1060 ty::Predicate::Equate(ty::Binder(ref data)) => {
1061 vec![data.0, data.1]
1063 ty::Predicate::Subtype(ty::Binder(SubtypePredicate { a, b, a_is_expected: _ })) => {
1066 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
1069 ty::Predicate::RegionOutlives(..) => {
1072 ty::Predicate::Projection(ref data) => {
1073 let trait_inputs = data.0.projection_ty.trait_ref.input_types();
1074 trait_inputs.chain(Some(data.0.ty)).collect()
1076 ty::Predicate::WellFormed(data) => {
1079 ty::Predicate::ObjectSafe(_trait_def_id) => {
1082 ty::Predicate::ClosureKind(_closure_def_id, _kind) => {
1087 // The only reason to collect into a vector here is that I was
1088 // too lazy to make the full (somewhat complicated) iterator
1089 // type that would be needed here. But I wanted this fn to
1090 // return an iterator conceptually, rather than a `Vec`, so as
1091 // to be closer to `Ty::walk`.
1095 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1097 Predicate::Trait(ref t) => {
1098 Some(t.to_poly_trait_ref())
1100 Predicate::Projection(..) |
1101 Predicate::Equate(..) |
1102 Predicate::Subtype(..) |
1103 Predicate::RegionOutlives(..) |
1104 Predicate::WellFormed(..) |
1105 Predicate::ObjectSafe(..) |
1106 Predicate::ClosureKind(..) |
1107 Predicate::TypeOutlives(..) => {
1114 /// Represents the bounds declared on a particular set of type
1115 /// parameters. Should eventually be generalized into a flag list of
1116 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1117 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1118 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1119 /// the `GenericPredicates` are expressed in terms of the bound type
1120 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1121 /// represented a set of bounds for some particular instantiation,
1122 /// meaning that the generic parameters have been substituted with
1127 /// struct Foo<T,U:Bar<T>> { ... }
1129 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1130 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1131 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1132 /// [usize:Bar<isize>]]`.
1134 pub struct InstantiatedPredicates<'tcx> {
1135 pub predicates: Vec<Predicate<'tcx>>,
1138 impl<'tcx> InstantiatedPredicates<'tcx> {
1139 pub fn empty() -> InstantiatedPredicates<'tcx> {
1140 InstantiatedPredicates { predicates: vec![] }
1143 pub fn is_empty(&self) -> bool {
1144 self.predicates.is_empty()
1148 /// When type checking, we use the `ParameterEnvironment` to track
1149 /// details about the type/lifetime parameters that are in scope.
1150 /// It primarily stores the bounds information.
1152 /// Note: This information might seem to be redundant with the data in
1153 /// `tcx.ty_param_defs`, but it is not. That table contains the
1154 /// parameter definitions from an "outside" perspective, but this
1155 /// struct will contain the bounds for a parameter as seen from inside
1156 /// the function body. Currently the only real distinction is that
1157 /// bound lifetime parameters are replaced with free ones, but in the
1158 /// future I hope to refine the representation of types so as to make
1159 /// more distinctions clearer.
1161 pub struct ParameterEnvironment<'tcx> {
1162 /// See `construct_free_substs` for details.
1163 pub free_substs: &'tcx Substs<'tcx>,
1165 /// Each type parameter has an implicit region bound that
1166 /// indicates it must outlive at least the function body (the user
1167 /// may specify stronger requirements). This field indicates the
1168 /// region of the callee. If it is `None`, then the parameter
1169 /// environment is for an item or something where the "callee" is
1171 pub implicit_region_bound: Option<ty::Region<'tcx>>,
1173 /// Obligations that the caller must satisfy. This is basically
1174 /// the set of bounds on the in-scope type parameters, translated
1175 /// into Obligations, and elaborated and normalized.
1176 pub caller_bounds: Vec<ty::Predicate<'tcx>>,
1178 /// Scope that is attached to free regions for this scope. This is
1179 /// usually the id of the fn body, but for more abstract scopes
1180 /// like structs we use None or the item extent.
1182 /// FIXME(#3696). It would be nice to refactor so that free
1183 /// regions don't have this implicit scope and instead introduce
1184 /// relationships in the environment.
1185 pub free_id_outlive: Option<CodeExtent<'tcx>>,
1187 /// A cache for `moves_by_default`.
1188 pub is_copy_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1190 /// A cache for `type_is_sized`
1191 pub is_sized_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1193 /// A cache for `type_is_freeze`
1194 pub is_freeze_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1197 impl<'a, 'tcx> ParameterEnvironment<'tcx> {
1198 pub fn with_caller_bounds(&self,
1199 caller_bounds: Vec<ty::Predicate<'tcx>>)
1200 -> ParameterEnvironment<'tcx>
1202 ParameterEnvironment {
1203 free_substs: self.free_substs,
1204 implicit_region_bound: self.implicit_region_bound,
1205 caller_bounds: caller_bounds,
1206 free_id_outlive: self.free_id_outlive,
1207 is_copy_cache: RefCell::new(FxHashMap()),
1208 is_sized_cache: RefCell::new(FxHashMap()),
1209 is_freeze_cache: RefCell::new(FxHashMap()),
1213 /// Construct a parameter environment given an item, impl item, or trait item
1214 pub fn for_item(tcx: TyCtxt<'a, 'tcx, 'tcx>, id: NodeId)
1215 -> ParameterEnvironment<'tcx> {
1216 match tcx.hir.find(id) {
1217 Some(hir_map::NodeImplItem(ref impl_item)) => {
1218 match impl_item.node {
1219 hir::ImplItemKind::Type(_) | hir::ImplItemKind::Const(..) => {
1220 // associated types don't have their own entry (for some reason),
1221 // so for now just grab environment for the impl
1222 let impl_id = tcx.hir.get_parent(id);
1223 let impl_def_id = tcx.hir.local_def_id(impl_id);
1224 tcx.construct_parameter_environment(impl_item.span,
1226 Some(tcx.item_extent(id)))
1228 hir::ImplItemKind::Method(_, ref body) => {
1229 tcx.construct_parameter_environment(
1231 tcx.hir.local_def_id(id),
1232 Some(tcx.call_site_extent(id, body.node_id)))
1236 Some(hir_map::NodeTraitItem(trait_item)) => {
1237 match trait_item.node {
1238 hir::TraitItemKind::Type(..) | hir::TraitItemKind::Const(..) => {
1239 // associated types don't have their own entry (for some reason),
1240 // so for now just grab environment for the trait
1241 let trait_id = tcx.hir.get_parent(id);
1242 let trait_def_id = tcx.hir.local_def_id(trait_id);
1243 tcx.construct_parameter_environment(trait_item.span,
1245 Some(tcx.item_extent(id)))
1247 hir::TraitItemKind::Method(_, ref body) => {
1248 // Use call-site for extent (unless this is a
1249 // trait method with no default; then fallback
1250 // to the method id).
1251 let extent = if let hir::TraitMethod::Provided(body_id) = *body {
1252 // default impl: use call_site extent as free_id_outlive bound.
1253 tcx.call_site_extent(id, body_id.node_id)
1255 // no default impl: use item extent as free_id_outlive bound.
1258 tcx.construct_parameter_environment(
1260 tcx.hir.local_def_id(id),
1265 Some(hir_map::NodeItem(item)) => {
1267 hir::ItemFn(.., body_id) => {
1268 // We assume this is a function.
1269 let fn_def_id = tcx.hir.local_def_id(id);
1271 tcx.construct_parameter_environment(
1274 Some(tcx.call_site_extent(id, body_id.node_id)))
1277 hir::ItemStruct(..) |
1278 hir::ItemUnion(..) |
1281 hir::ItemConst(..) |
1282 hir::ItemStatic(..) => {
1283 let def_id = tcx.hir.local_def_id(id);
1284 tcx.construct_parameter_environment(item.span,
1286 Some(tcx.item_extent(id)))
1288 hir::ItemTrait(..) => {
1289 let def_id = tcx.hir.local_def_id(id);
1290 tcx.construct_parameter_environment(item.span,
1292 Some(tcx.item_extent(id)))
1295 span_bug!(item.span,
1296 "ParameterEnvironment::for_item():
1297 can't create a parameter \
1298 environment for this kind of item")
1302 Some(hir_map::NodeExpr(expr)) => {
1303 // This is a convenience to allow closures to work.
1304 if let hir::ExprClosure(.., body, _) = expr.node {
1305 let def_id = tcx.hir.local_def_id(id);
1306 let base_def_id = tcx.closure_base_def_id(def_id);
1307 tcx.construct_parameter_environment(
1310 Some(tcx.call_site_extent(id, body.node_id)))
1312 tcx.empty_parameter_environment()
1315 Some(hir_map::NodeForeignItem(item)) => {
1316 let def_id = tcx.hir.local_def_id(id);
1317 tcx.construct_parameter_environment(item.span,
1321 Some(hir_map::NodeStructCtor(..)) |
1322 Some(hir_map::NodeVariant(..)) => {
1323 let def_id = tcx.hir.local_def_id(id);
1324 tcx.construct_parameter_environment(tcx.hir.span(id),
1329 bug!("ParameterEnvironment::from_item(): \
1330 `{}` = {:?} is unsupported",
1331 tcx.hir.node_to_string(id), it)
1337 #[derive(Copy, Clone, Debug)]
1338 pub struct Destructor {
1339 /// The def-id of the destructor method
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 }
1442 #[derive(RustcEncodable, RustcDecodable, Default)]
1443 flags ReprFlags: u8 {
1444 const IS_C = 1 << 0,
1445 const IS_PACKED = 1 << 1,
1446 const IS_SIMD = 1 << 2,
1447 // Internal only for now. If true, don't reorder fields.
1448 const IS_LINEAR = 1 << 3,
1450 // Any of these flags being set prevent field reordering optimisation.
1451 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1452 ReprFlags::IS_PACKED.bits |
1453 ReprFlags::IS_SIMD.bits |
1454 ReprFlags::IS_LINEAR.bits,
1458 impl_stable_hash_for!(struct ReprFlags {
1464 /// Represents the repr options provided by the user,
1465 #[derive(Copy, Clone, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1466 pub struct ReprOptions {
1467 pub int: Option<attr::IntType>,
1469 pub flags: ReprFlags,
1472 impl_stable_hash_for!(struct ReprOptions {
1479 pub fn new(tcx: TyCtxt, did: DefId) -> ReprOptions {
1480 let mut flags = ReprFlags::empty();
1481 let mut size = None;
1482 let mut max_align = 0;
1483 for attr in tcx.get_attrs(did).iter() {
1484 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1485 flags.insert(match r {
1486 attr::ReprExtern => ReprFlags::IS_C,
1487 attr::ReprPacked => ReprFlags::IS_PACKED,
1488 attr::ReprSimd => ReprFlags::IS_SIMD,
1489 attr::ReprInt(i) => {
1493 attr::ReprAlign(align) => {
1494 max_align = cmp::max(align, max_align);
1501 // FIXME(eddyb) This is deprecated and should be removed.
1502 if tcx.has_attr(did, "simd") {
1503 flags.insert(ReprFlags::IS_SIMD);
1506 // This is here instead of layout because the choice must make it into metadata.
1507 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1508 flags.insert(ReprFlags::IS_LINEAR);
1510 ReprOptions { int: size, align: max_align, flags: flags }
1514 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1516 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1518 pub fn packed(&self) -> bool { self.flags.contains(ReprFlags::IS_PACKED) }
1520 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1522 pub fn discr_type(&self) -> attr::IntType {
1523 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Is))
1526 /// Returns true if this `#[repr()]` should inhabit "smart enum
1527 /// layout" optimizations, such as representing `Foo<&T>` as a
1529 pub fn inhibit_enum_layout_opt(&self) -> bool {
1530 self.c() || self.int.is_some()
1534 impl<'a, 'gcx, 'tcx> AdtDef {
1538 variants: Vec<VariantDef>,
1539 repr: ReprOptions) -> Self {
1540 let mut flags = AdtFlags::NO_ADT_FLAGS;
1541 let attrs = tcx.get_attrs(did);
1542 if attr::contains_name(&attrs, "fundamental") {
1543 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1545 if Some(did) == tcx.lang_items.phantom_data() {
1546 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1548 if Some(did) == tcx.lang_items.owned_box() {
1549 flags = flags | AdtFlags::IS_BOX;
1552 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
1553 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
1554 AdtKind::Struct => {}
1565 pub fn is_struct(&self) -> bool {
1566 !self.is_union() && !self.is_enum()
1570 pub fn is_union(&self) -> bool {
1571 self.flags.intersects(AdtFlags::IS_UNION)
1575 pub fn is_enum(&self) -> bool {
1576 self.flags.intersects(AdtFlags::IS_ENUM)
1579 /// Returns the kind of the ADT - Struct or Enum.
1581 pub fn adt_kind(&self) -> AdtKind {
1584 } else if self.is_union() {
1591 pub fn descr(&self) -> &'static str {
1592 match self.adt_kind() {
1593 AdtKind::Struct => "struct",
1594 AdtKind::Union => "union",
1595 AdtKind::Enum => "enum",
1599 pub fn variant_descr(&self) -> &'static str {
1600 match self.adt_kind() {
1601 AdtKind::Struct => "struct",
1602 AdtKind::Union => "union",
1603 AdtKind::Enum => "variant",
1607 /// Returns whether this type is #[fundamental] for the purposes
1608 /// of coherence checking.
1610 pub fn is_fundamental(&self) -> bool {
1611 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
1614 /// Returns true if this is PhantomData<T>.
1616 pub fn is_phantom_data(&self) -> bool {
1617 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
1620 /// Returns true if this is Box<T>.
1622 pub fn is_box(&self) -> bool {
1623 self.flags.intersects(AdtFlags::IS_BOX)
1626 /// Returns whether this type has a destructor.
1627 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
1628 self.destructor(tcx).is_some()
1631 /// Asserts this is a struct and returns the struct's unique
1633 pub fn struct_variant(&self) -> &VariantDef {
1634 assert!(!self.is_enum());
1639 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
1640 tcx.predicates_of(self.did)
1643 /// Returns an iterator over all fields contained
1646 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
1647 self.variants.iter().flat_map(|v| v.fields.iter())
1651 pub fn is_univariant(&self) -> bool {
1652 self.variants.len() == 1
1655 pub fn is_payloadfree(&self) -> bool {
1656 !self.variants.is_empty() &&
1657 self.variants.iter().all(|v| v.fields.is_empty())
1660 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
1663 .find(|v| v.did == vid)
1664 .expect("variant_with_id: unknown variant")
1667 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1670 .position(|v| v.did == vid)
1671 .expect("variant_index_with_id: unknown variant")
1674 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
1676 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
1677 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
1678 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.struct_variant(),
1679 _ => 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 let substs = Substs::empty();
1693 match tcx.const_eval((expr_did, substs)) {
1694 Ok(ConstVal::Integral(v)) => {
1698 if !expr_did.is_local() {
1699 span_bug!(tcx.def_span(expr_did),
1700 "variant discriminant evaluation succeeded \
1701 in its crate but failed locally: {:?}", err);
1706 prev_discr = Some(discr);
1712 /// Compute the discriminant value used by a specific variant.
1713 /// Unlike `discriminants`, this is (amortized) constant-time,
1714 /// only doing at most one query for evaluating an explicit
1715 /// discriminant (the last one before the requested variant),
1716 /// assuming there are no constant-evaluation errors there.
1717 pub fn discriminant_for_variant(&self,
1718 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1719 variant_index: usize)
1721 let repr_type = self.repr.discr_type();
1722 let mut explicit_value = repr_type.initial_discriminant(tcx.global_tcx());
1723 let mut explicit_index = variant_index;
1725 match self.variants[explicit_index].discr {
1726 ty::VariantDiscr::Relative(0) => break,
1727 ty::VariantDiscr::Relative(distance) => {
1728 explicit_index -= distance;
1730 ty::VariantDiscr::Explicit(expr_did) => {
1731 let substs = Substs::empty();
1732 match tcx.const_eval((expr_did, substs)) {
1733 Ok(ConstVal::Integral(v)) => {
1738 if !expr_did.is_local() {
1739 span_bug!(tcx.def_span(expr_did),
1740 "variant discriminant evaluation succeeded \
1741 in its crate but failed locally: {:?}", err);
1743 if explicit_index == 0 {
1746 explicit_index -= 1;
1752 let discr = explicit_value.to_u128_unchecked()
1753 .wrapping_add((variant_index - explicit_index) as u128);
1755 attr::UnsignedInt(ty) => {
1756 ConstInt::new_unsigned_truncating(discr, ty,
1757 tcx.sess.target.uint_type)
1759 attr::SignedInt(ty) => {
1760 ConstInt::new_signed_truncating(discr as i128, ty,
1761 tcx.sess.target.int_type)
1766 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
1767 tcx.adt_destructor(self.did)
1770 /// Returns a list of types such that `Self: Sized` if and only
1771 /// if that type is Sized, or `TyErr` if this type is recursive.
1773 /// Oddly enough, checking that the sized-constraint is Sized is
1774 /// actually more expressive than checking all members:
1775 /// the Sized trait is inductive, so an associated type that references
1776 /// Self would prevent its containing ADT from being Sized.
1778 /// Due to normalization being eager, this applies even if
1779 /// the associated type is behind a pointer, e.g. issue #31299.
1780 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
1781 match queries::adt_sized_constraint::try_get(tcx, DUMMY_SP, self.did) {
1784 debug!("adt_sized_constraint: {:?} is recursive", self);
1785 // This should be reported as an error by `check_representable`.
1787 // Consider the type as Sized in the meanwhile to avoid
1789 tcx.intern_type_list(&[tcx.types.err])
1794 fn sized_constraint_for_ty(&self,
1795 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1798 let result = match ty.sty {
1799 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
1800 TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
1801 TyArray(..) | TyClosure(..) | TyNever => {
1805 TyStr | TyDynamic(..) | TySlice(_) | TyError => {
1806 // these are never sized - return the target type
1810 TyTuple(ref tys, _) => {
1813 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
1817 TyAdt(adt, substs) => {
1819 let adt_tys = adt.sized_constraint(tcx);
1820 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
1823 .map(|ty| ty.subst(tcx, substs))
1824 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
1828 TyProjection(..) | TyAnon(..) => {
1829 // must calculate explicitly.
1830 // FIXME: consider special-casing always-Sized projections
1835 // perf hack: if there is a `T: Sized` bound, then
1836 // we know that `T` is Sized and do not need to check
1839 let sized_trait = match tcx.lang_items.sized_trait() {
1841 _ => return vec![ty]
1843 let sized_predicate = Binder(TraitRef {
1844 def_id: sized_trait,
1845 substs: tcx.mk_substs_trait(ty, &[])
1847 let predicates = tcx.predicates_of(self.did).predicates;
1848 if predicates.into_iter().any(|p| p == sized_predicate) {
1856 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
1860 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
1865 impl<'a, 'gcx, 'tcx> VariantDef {
1867 pub fn find_field_named(&self,
1869 -> Option<&FieldDef> {
1870 self.fields.iter().find(|f| f.name == name)
1874 pub fn index_of_field_named(&self,
1877 self.fields.iter().position(|f| f.name == name)
1881 pub fn field_named(&self, name: ast::Name) -> &FieldDef {
1882 self.find_field_named(name).unwrap()
1886 impl<'a, 'gcx, 'tcx> FieldDef {
1887 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1888 tcx.type_of(self.did).subst(tcx, subst)
1892 /// Records the substitutions used to translate the polytype for an
1893 /// item into the monotype of an item reference.
1894 #[derive(Clone, RustcEncodable, RustcDecodable)]
1895 pub struct ItemSubsts<'tcx> {
1896 pub substs: &'tcx Substs<'tcx>,
1899 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1900 pub enum ClosureKind {
1901 // Warning: Ordering is significant here! The ordering is chosen
1902 // because the trait Fn is a subtrait of FnMut and so in turn, and
1903 // hence we order it so that Fn < FnMut < FnOnce.
1909 impl<'a, 'tcx> ClosureKind {
1910 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
1912 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
1913 ClosureKind::FnMut => {
1914 tcx.require_lang_item(FnMutTraitLangItem)
1916 ClosureKind::FnOnce => {
1917 tcx.require_lang_item(FnOnceTraitLangItem)
1922 /// True if this a type that impls this closure kind
1923 /// must also implement `other`.
1924 pub fn extends(self, other: ty::ClosureKind) -> bool {
1925 match (self, other) {
1926 (ClosureKind::Fn, ClosureKind::Fn) => true,
1927 (ClosureKind::Fn, ClosureKind::FnMut) => true,
1928 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
1929 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
1930 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
1931 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
1937 impl<'tcx> TyS<'tcx> {
1938 /// Iterator that walks `self` and any types reachable from
1939 /// `self`, in depth-first order. Note that just walks the types
1940 /// that appear in `self`, it does not descend into the fields of
1941 /// structs or variants. For example:
1944 /// isize => { isize }
1945 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
1946 /// [isize] => { [isize], isize }
1948 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
1949 TypeWalker::new(self)
1952 /// Iterator that walks the immediate children of `self`. Hence
1953 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
1954 /// (but not `i32`, like `walk`).
1955 pub fn walk_shallow(&'tcx self) -> AccIntoIter<walk::TypeWalkerArray<'tcx>> {
1956 walk::walk_shallow(self)
1959 /// Walks `ty` and any types appearing within `ty`, invoking the
1960 /// callback `f` on each type. If the callback returns false, then the
1961 /// children of the current type are ignored.
1963 /// Note: prefer `ty.walk()` where possible.
1964 pub fn maybe_walk<F>(&'tcx self, mut f: F)
1965 where F : FnMut(Ty<'tcx>) -> bool
1967 let mut walker = self.walk();
1968 while let Some(ty) = walker.next() {
1970 walker.skip_current_subtree();
1976 impl<'tcx> ItemSubsts<'tcx> {
1977 pub fn is_noop(&self) -> bool {
1978 self.substs.is_noop()
1982 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1983 pub enum LvaluePreference {
1988 impl LvaluePreference {
1989 pub fn from_mutbl(m: hir::Mutability) -> Self {
1991 hir::MutMutable => PreferMutLvalue,
1992 hir::MutImmutable => NoPreference,
1998 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2000 hir::MutMutable => MutBorrow,
2001 hir::MutImmutable => ImmBorrow,
2005 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2006 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2007 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2009 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2011 MutBorrow => hir::MutMutable,
2012 ImmBorrow => hir::MutImmutable,
2014 // We have no type corresponding to a unique imm borrow, so
2015 // use `&mut`. It gives all the capabilities of an `&uniq`
2016 // and hence is a safe "over approximation".
2017 UniqueImmBorrow => hir::MutMutable,
2021 pub fn to_user_str(&self) -> &'static str {
2023 MutBorrow => "mutable",
2024 ImmBorrow => "immutable",
2025 UniqueImmBorrow => "uniquely immutable",
2030 #[derive(Debug, Clone)]
2031 pub enum Attributes<'gcx> {
2032 Owned(Rc<[ast::Attribute]>),
2033 Borrowed(&'gcx [ast::Attribute])
2036 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2037 type Target = [ast::Attribute];
2039 fn deref(&self) -> &[ast::Attribute] {
2041 &Attributes::Owned(ref data) => &data,
2042 &Attributes::Borrowed(data) => data
2047 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2048 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2049 self.typeck_tables_of(self.hir.body_owner_def_id(body))
2052 /// Returns an iterator of the def-ids for all body-owners in this
2053 /// crate. If you would prefer to iterate over the bodies
2054 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
2055 pub fn body_owners(self) -> impl Iterator<Item = DefId> + 'a {
2059 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
2062 pub fn expr_span(self, id: NodeId) -> Span {
2063 match self.hir.find(id) {
2064 Some(hir_map::NodeExpr(e)) => {
2068 bug!("Node id {} is not an expr: {:?}", id, f);
2071 bug!("Node id {} is not present in the node map", id);
2076 pub fn local_var_name_str(self, id: NodeId) -> InternedString {
2077 match self.hir.find(id) {
2078 Some(hir_map::NodeLocal(pat)) => {
2080 hir::PatKind::Binding(_, _, ref path1, _) => path1.node.as_str(),
2082 bug!("Variable id {} maps to {:?}, not local", id, pat);
2086 r => bug!("Variable id {} maps to {:?}, not local", id, r),
2090 pub fn expr_is_lval(self, expr: &hir::Expr) -> bool {
2092 hir::ExprPath(hir::QPath::Resolved(_, ref path)) => {
2094 Def::Local(..) | Def::Upvar(..) | Def::Static(..) | Def::Err => true,
2099 hir::ExprType(ref e, _) => {
2100 self.expr_is_lval(e)
2103 hir::ExprUnary(hir::UnDeref, _) |
2104 hir::ExprField(..) |
2105 hir::ExprTupField(..) |
2106 hir::ExprIndex(..) => {
2110 // Partially qualified paths in expressions can only legally
2111 // refer to associated items which are always rvalues.
2112 hir::ExprPath(hir::QPath::TypeRelative(..)) |
2115 hir::ExprMethodCall(..) |
2116 hir::ExprStruct(..) |
2119 hir::ExprMatch(..) |
2120 hir::ExprClosure(..) |
2121 hir::ExprBlock(..) |
2122 hir::ExprRepeat(..) |
2123 hir::ExprArray(..) |
2124 hir::ExprBreak(..) |
2125 hir::ExprAgain(..) |
2127 hir::ExprWhile(..) |
2129 hir::ExprAssign(..) |
2130 hir::ExprInlineAsm(..) |
2131 hir::ExprAssignOp(..) |
2133 hir::ExprUnary(..) |
2135 hir::ExprAddrOf(..) |
2136 hir::ExprBinary(..) |
2137 hir::ExprCast(..) => {
2143 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2144 self.associated_items(id)
2145 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2149 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2150 self.associated_items(did).any(|item| {
2151 item.relevant_for_never()
2155 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2156 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2157 match self.hir.get(node_id) {
2158 hir_map::NodeTraitItem(_) | hir_map::NodeImplItem(_) => true,
2162 match self.describe_def(def_id).expect("no def for def-id") {
2163 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2168 if is_associated_item {
2169 Some(self.associated_item(def_id))
2175 fn associated_item_from_trait_item_ref(self,
2176 parent_def_id: DefId,
2177 parent_vis: &hir::Visibility,
2178 trait_item_ref: &hir::TraitItemRef)
2180 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2181 let (kind, has_self) = match trait_item_ref.kind {
2182 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2183 hir::AssociatedItemKind::Method { has_self } => {
2184 (ty::AssociatedKind::Method, has_self)
2186 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2190 name: trait_item_ref.name,
2192 // Visibility of trait items is inherited from their traits.
2193 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2194 defaultness: trait_item_ref.defaultness,
2196 container: TraitContainer(parent_def_id),
2197 method_has_self_argument: has_self
2201 fn associated_item_from_impl_item_ref(self,
2202 parent_def_id: DefId,
2203 impl_item_ref: &hir::ImplItemRef)
2205 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2206 let (kind, has_self) = match impl_item_ref.kind {
2207 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2208 hir::AssociatedItemKind::Method { has_self } => {
2209 (ty::AssociatedKind::Method, has_self)
2211 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2214 ty::AssociatedItem {
2215 name: impl_item_ref.name,
2217 // Visibility of trait impl items doesn't matter.
2218 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2219 defaultness: impl_item_ref.defaultness,
2221 container: ImplContainer(parent_def_id),
2222 method_has_self_argument: has_self
2226 #[inline] // FIXME(#35870) Avoid closures being unexported due to impl Trait.
2227 pub fn associated_items(self, def_id: DefId)
2228 -> impl Iterator<Item = ty::AssociatedItem> + 'a {
2229 let def_ids = self.associated_item_def_ids(def_id);
2230 (0..def_ids.len()).map(move |i| self.associated_item(def_ids[i]))
2233 /// Returns true if the impls are the same polarity and are implementing
2234 /// a trait which contains no items
2235 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2236 if !self.sess.features.borrow().overlapping_marker_traits {
2239 let trait1_is_empty = self.impl_trait_ref(def_id1)
2240 .map_or(false, |trait_ref| {
2241 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2243 let trait2_is_empty = self.impl_trait_ref(def_id2)
2244 .map_or(false, |trait_ref| {
2245 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2247 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2252 // Returns `ty::VariantDef` if `def` refers to a struct,
2253 // or variant or their constructors, panics otherwise.
2254 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2256 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2257 let enum_did = self.parent_def_id(did).unwrap();
2258 self.adt_def(enum_did).variant_with_id(did)
2260 Def::Struct(did) | Def::Union(did) => {
2261 self.adt_def(did).struct_variant()
2263 Def::StructCtor(ctor_did, ..) => {
2264 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2265 self.adt_def(did).struct_variant()
2267 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2271 pub fn def_key(self, id: DefId) -> hir_map::DefKey {
2273 self.hir.def_key(id)
2275 self.sess.cstore.def_key(id)
2279 /// Convert a `DefId` into its fully expanded `DefPath` (every
2280 /// `DefId` is really just an interned def-path).
2282 /// Note that if `id` is not local to this crate, the result will
2283 /// be a non-local `DefPath`.
2284 pub fn def_path(self, id: DefId) -> hir_map::DefPath {
2286 self.hir.def_path(id)
2288 self.sess.cstore.def_path(id)
2293 pub fn def_path_hash(self, def_id: DefId) -> u64 {
2294 if def_id.is_local() {
2295 self.hir.definitions().def_path_hash(def_id.index)
2297 self.sess.cstore.def_path_hash(def_id)
2301 pub fn vis_is_accessible_from(self, vis: Visibility, block: NodeId) -> bool {
2302 vis.is_accessible_from(self.hir.local_def_id(self.hir.get_module_parent(block)), self)
2305 pub fn item_name(self, id: DefId) -> ast::Name {
2306 if let Some(id) = self.hir.as_local_node_id(id) {
2308 } else if id.index == CRATE_DEF_INDEX {
2309 self.sess.cstore.original_crate_name(id.krate)
2311 let def_key = self.sess.cstore.def_key(id);
2312 // The name of a StructCtor is that of its struct parent.
2313 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2314 self.item_name(DefId {
2316 index: def_key.parent.unwrap()
2319 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2320 bug!("item_name: no name for {:?}", self.def_path(id));
2326 /// Given the did of an item, returns its (optimized) MIR, borrowed immutably.
2327 pub fn item_mir(self, did: DefId) -> Ref<'gcx, Mir<'gcx>> {
2328 self.optimized_mir(did).borrow()
2331 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2332 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2333 -> Ref<'gcx, Mir<'gcx>>
2336 ty::InstanceDef::Item(did) => {
2339 ty::InstanceDef::Intrinsic(..) |
2340 ty::InstanceDef::FnPtrShim(..) |
2341 ty::InstanceDef::Virtual(..) |
2342 ty::InstanceDef::ClosureOnceShim { .. } |
2343 ty::InstanceDef::DropGlue(..) => {
2344 self.mir_shims(instance).borrow()
2349 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2350 /// Returns None if there is no MIR for the DefId
2351 pub fn maybe_item_mir(self, did: DefId) -> Option<Ref<'gcx, Mir<'gcx>>> {
2352 if did.is_local() && !self.mir_keys(LOCAL_CRATE).contains(&did) {
2356 if !did.is_local() && !self.is_item_mir_available(did) {
2360 Some(self.item_mir(did))
2363 /// Get the attributes of a definition.
2364 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2365 if let Some(id) = self.hir.as_local_node_id(did) {
2366 Attributes::Borrowed(self.hir.attrs(id))
2368 Attributes::Owned(self.sess.cstore.item_attrs(did))
2372 /// Determine whether an item is annotated with an attribute
2373 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2374 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2377 pub fn trait_has_default_impl(self, trait_def_id: DefId) -> bool {
2378 let def = self.trait_def(trait_def_id);
2379 def.flags.get().intersects(TraitFlags::HAS_DEFAULT_IMPL)
2382 /// Populates the type context with all the implementations for the given
2383 /// trait if necessary.
2384 pub fn populate_implementations_for_trait_if_necessary(self, trait_id: DefId) {
2385 if trait_id.is_local() {
2389 // The type is not local, hence we are reading this out of
2390 // metadata and don't need to track edges.
2391 let _ignore = self.dep_graph.in_ignore();
2393 let def = self.trait_def(trait_id);
2394 if def.flags.get().intersects(TraitFlags::HAS_REMOTE_IMPLS) {
2398 debug!("populate_implementations_for_trait_if_necessary: searching for {:?}", def);
2400 for impl_def_id in self.sess.cstore.implementations_of_trait(Some(trait_id)) {
2401 let trait_ref = self.impl_trait_ref(impl_def_id).unwrap();
2403 // Record the trait->implementation mapping.
2404 let parent = self.sess.cstore.impl_parent(impl_def_id).unwrap_or(trait_id);
2405 def.record_remote_impl(self, impl_def_id, trait_ref, parent);
2408 def.flags.set(def.flags.get() | TraitFlags::HAS_REMOTE_IMPLS);
2411 /// Given the def_id of an impl, return the def_id of the trait it implements.
2412 /// If it implements no trait, return `None`.
2413 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2414 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2417 /// If the given def ID describes a method belonging to an impl, return the
2418 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2419 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2420 let item = if def_id.krate != LOCAL_CRATE {
2421 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2422 Some(self.associated_item(def_id))
2427 self.opt_associated_item(def_id)
2431 Some(trait_item) => {
2432 match trait_item.container {
2433 TraitContainer(_) => None,
2434 ImplContainer(def_id) => Some(def_id),
2441 /// If the given def ID describes an item belonging to a trait,
2442 /// return the ID of the trait that the trait item belongs to.
2443 /// Otherwise, return `None`.
2444 pub fn trait_of_item(self, def_id: DefId) -> Option<DefId> {
2445 if def_id.krate != LOCAL_CRATE {
2446 return self.sess.cstore.trait_of_item(def_id);
2448 self.opt_associated_item(def_id)
2449 .and_then(|associated_item| {
2450 match associated_item.container {
2451 TraitContainer(def_id) => Some(def_id),
2452 ImplContainer(_) => None
2457 /// Construct a parameter environment suitable for static contexts or other contexts where there
2458 /// are no free type/lifetime parameters in scope.
2459 pub fn empty_parameter_environment(self) -> ParameterEnvironment<'tcx> {
2460 ty::ParameterEnvironment {
2461 free_substs: self.intern_substs(&[]),
2462 caller_bounds: Vec::new(),
2463 implicit_region_bound: None,
2464 free_id_outlive: None,
2465 is_copy_cache: RefCell::new(FxHashMap()),
2466 is_sized_cache: RefCell::new(FxHashMap()),
2467 is_freeze_cache: RefCell::new(FxHashMap()),
2471 /// Constructs and returns a substitution that can be applied to move from
2472 /// the "outer" view of a type or method to the "inner" view.
2473 /// In general, this means converting from bound parameters to
2474 /// free parameters. Since we currently represent bound/free type
2475 /// parameters in the same way, this only has an effect on regions.
2476 pub fn construct_free_substs(self,
2478 free_id_outlive: Option<CodeExtent<'gcx>>)
2479 -> &'gcx Substs<'gcx> {
2481 let substs = Substs::for_item(self.global_tcx(), def_id, |def, _| {
2482 // map bound 'a => free 'a
2483 self.global_tcx().mk_region(ReFree(FreeRegion {
2484 scope: free_id_outlive,
2485 bound_region: def.to_bound_region()
2489 self.global_tcx().mk_param_from_def(def)
2492 debug!("construct_parameter_environment: {:?}", substs);
2496 /// See `ParameterEnvironment` struct def'n for details.
2497 /// If you were using `free_id: NodeId`, you might try `self.region_maps().item_extent(free_id)`
2498 /// for the `free_id_outlive` parameter. (But note that this is not always quite right.)
2499 pub fn construct_parameter_environment(self,
2502 free_id_outlive: Option<CodeExtent<'gcx>>)
2503 -> ParameterEnvironment<'gcx>
2506 // Construct the free substs.
2509 let free_substs = self.construct_free_substs(def_id, free_id_outlive);
2512 // Compute the bounds on Self and the type parameters.
2515 let tcx = self.global_tcx();
2516 let generic_predicates = tcx.predicates_of(def_id);
2517 let bounds = generic_predicates.instantiate(tcx, free_substs);
2518 let bounds = tcx.liberate_late_bound_regions(free_id_outlive, &ty::Binder(bounds));
2519 let predicates = bounds.predicates;
2521 // Finally, we have to normalize the bounds in the environment, in
2522 // case they contain any associated type projections. This process
2523 // can yield errors if the put in illegal associated types, like
2524 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2525 // report these errors right here; this doesn't actually feel
2526 // right to me, because constructing the environment feels like a
2527 // kind of a "idempotent" action, but I'm not sure where would be
2528 // a better place. In practice, we construct environments for
2529 // every fn once during type checking, and we'll abort if there
2530 // are any errors at that point, so after type checking you can be
2531 // sure that this will succeed without errors anyway.
2534 let unnormalized_env = ty::ParameterEnvironment {
2535 free_substs: free_substs,
2536 implicit_region_bound: free_id_outlive.map(|f| tcx.mk_region(ty::ReScope(f))),
2537 caller_bounds: predicates,
2538 free_id_outlive: free_id_outlive,
2539 is_copy_cache: RefCell::new(FxHashMap()),
2540 is_sized_cache: RefCell::new(FxHashMap()),
2541 is_freeze_cache: RefCell::new(FxHashMap()),
2544 let body_id = free_id_outlive.map(|f| f.node_id())
2545 .unwrap_or(DUMMY_NODE_ID);
2546 let cause = traits::ObligationCause::misc(span, body_id);
2547 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
2550 pub fn node_scope_region(self, id: NodeId) -> Region<'tcx> {
2551 self.mk_region(ty::ReScope(self.node_extent(id)))
2554 pub fn visit_all_item_likes_in_krate<V,F>(self,
2557 where F: FnMut(DefId) -> DepNode<DefId>, V: ItemLikeVisitor<'gcx>
2559 dep_graph::visit_all_item_likes_in_krate(self.global_tcx(), dep_node_fn, visitor);
2562 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2563 /// with the name of the crate containing the impl.
2564 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2565 if impl_did.is_local() {
2566 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2567 Ok(self.hir.span(node_id))
2569 Err(self.sess.cstore.crate_name(impl_did.krate))
2574 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2575 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2576 F: FnOnce(&[hir::Freevar]) -> T,
2578 match self.freevars.borrow().get(&fid) {
2580 Some(d) => f(&d[..])
2585 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
2588 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2589 let parent_id = tcx.hir.get_parent(id);
2590 let parent_def_id = tcx.hir.local_def_id(parent_id);
2591 let parent_item = tcx.hir.expect_item(parent_id);
2592 match parent_item.node {
2593 hir::ItemImpl(.., ref impl_item_refs) => {
2594 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2595 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2597 debug_assert_eq!(assoc_item.def_id, def_id);
2602 hir::ItemTrait(.., ref trait_item_refs) => {
2603 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2604 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2607 debug_assert_eq!(assoc_item.def_id, def_id);
2615 span_bug!(parent_item.span,
2616 "unexpected parent of trait or impl item or item not found: {:?}",
2620 /// Calculates the Sized-constraint.
2622 /// In fact, there are only a few options for the types in the constraint:
2623 /// - an obviously-unsized type
2624 /// - a type parameter or projection whose Sizedness can't be known
2625 /// - a tuple of type parameters or projections, if there are multiple
2627 /// - a TyError, if a type contained itself. The representability
2628 /// check should catch this case.
2629 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2631 -> &'tcx [Ty<'tcx>] {
2632 let def = tcx.adt_def(def_id);
2634 let result = tcx.intern_type_list(&def.variants.iter().flat_map(|v| {
2637 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2638 }).collect::<Vec<_>>());
2640 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2645 /// Calculates the dtorck constraint for a type.
2646 fn adt_dtorck_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2648 -> DtorckConstraint<'tcx> {
2649 let def = tcx.adt_def(def_id);
2650 let span = tcx.def_span(def_id);
2651 debug!("dtorck_constraint: {:?}", def);
2653 if def.is_phantom_data() {
2654 let result = DtorckConstraint {
2657 tcx.mk_param_from_def(&tcx.generics_of(def_id).types[0])
2660 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2664 let mut result = def.all_fields()
2665 .map(|field| tcx.type_of(field.did))
2666 .map(|fty| tcx.dtorck_constraint_for_ty(span, fty, 0, fty))
2667 .collect::<Result<DtorckConstraint, ErrorReported>>()
2668 .unwrap_or(DtorckConstraint::empty());
2669 result.outlives.extend(tcx.destructor_constraints(def));
2672 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2677 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2680 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2681 let item = tcx.hir.expect_item(id);
2682 let vec: Vec<_> = match item.node {
2683 hir::ItemTrait(.., ref trait_item_refs) => {
2684 trait_item_refs.iter()
2685 .map(|trait_item_ref| trait_item_ref.id)
2686 .map(|id| tcx.hir.local_def_id(id.node_id))
2689 hir::ItemImpl(.., ref impl_item_refs) => {
2690 impl_item_refs.iter()
2691 .map(|impl_item_ref| impl_item_ref.id)
2692 .map(|id| tcx.hir.local_def_id(id.node_id))
2695 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2700 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
2701 tcx.hir.span_if_local(def_id).unwrap()
2704 pub fn provide(providers: &mut ty::maps::Providers) {
2705 *providers = ty::maps::Providers {
2707 associated_item_def_ids,
2708 adt_sized_constraint,
2709 adt_dtorck_constraint,
2715 pub fn provide_extern(providers: &mut ty::maps::Providers) {
2716 *providers = ty::maps::Providers {
2717 adt_sized_constraint,
2718 adt_dtorck_constraint,
2724 /// A map for the local crate mapping each type to a vector of its
2725 /// inherent impls. This is not meant to be used outside of coherence;
2726 /// rather, you should request the vector for a specific type via
2727 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2728 /// (constructing this map requires touching the entire crate).
2729 #[derive(Clone, Debug)]
2730 pub struct CrateInherentImpls {
2731 pub inherent_impls: DefIdMap<Rc<Vec<DefId>>>,
2734 /// A set of constraints that need to be satisfied in order for
2735 /// a type to be valid for destruction.
2736 #[derive(Clone, Debug)]
2737 pub struct DtorckConstraint<'tcx> {
2738 /// Types that are required to be alive in order for this
2739 /// type to be valid for destruction.
2740 pub outlives: Vec<ty::subst::Kind<'tcx>>,
2741 /// Types that could not be resolved: projections and params.
2742 pub dtorck_types: Vec<Ty<'tcx>>,
2745 impl<'tcx> FromIterator<DtorckConstraint<'tcx>> for DtorckConstraint<'tcx>
2747 fn from_iter<I: IntoIterator<Item=DtorckConstraint<'tcx>>>(iter: I) -> Self {
2748 let mut result = Self::empty();
2750 for constraint in iter {
2751 result.outlives.extend(constraint.outlives);
2752 result.dtorck_types.extend(constraint.dtorck_types);
2760 impl<'tcx> DtorckConstraint<'tcx> {
2761 fn empty() -> DtorckConstraint<'tcx> {
2764 dtorck_types: vec![]
2768 fn dedup<'a>(&mut self) {
2769 let mut outlives = FxHashSet();
2770 let mut dtorck_types = FxHashSet();
2772 self.outlives.retain(|&val| outlives.replace(val).is_none());
2773 self.dtorck_types.retain(|&val| dtorck_types.replace(val).is_none());
2777 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord)]
2778 pub struct SymbolName {
2779 // FIXME: we don't rely on interning or equality here - better have
2780 // this be a `&'tcx str`.
2781 pub name: InternedString
2784 impl Deref for SymbolName {
2787 fn deref(&self) -> &str { &self.name }
2790 impl fmt::Display for SymbolName {
2791 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2792 fmt::Display::fmt(&self.name, fmt)