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::Issue32330;
71 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid, SkolemizedRegionVid};
72 pub use self::sty::BoundRegion::*;
73 pub use self::sty::InferTy::*;
74 pub use self::sty::Region::*;
75 pub use self::sty::TypeVariants::*;
77 pub use self::context::{TyCtxt, GlobalArenas, tls};
78 pub use self::context::{Lift, TypeckTables};
80 pub use self::instance::{Instance, InstanceDef};
82 pub use self::trait_def::{TraitDef, TraitFlags};
84 pub use self::maps::queries;
91 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: Rc<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.type_of(impl_def_id),
170 trait_ref: tcx.impl_trait_ref(impl_def_id),
171 predicates: tcx.predicates_of(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,
429 const FREEZENESS_CACHED = 1 << 20,
430 const IS_FREEZE = 1 << 21,
431 const NEEDS_DROP_CACHED = 1 << 22,
432 const NEEDS_DROP = 1 << 23,
436 pub struct TyS<'tcx> {
437 pub sty: TypeVariants<'tcx>,
438 pub flags: Cell<TypeFlags>,
440 // the maximal depth of any bound regions appearing in this type.
444 impl<'tcx> PartialEq for TyS<'tcx> {
446 fn eq(&self, other: &TyS<'tcx>) -> bool {
447 // (self as *const _) == (other as *const _)
448 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
451 impl<'tcx> Eq for TyS<'tcx> {}
453 impl<'tcx> Hash for TyS<'tcx> {
454 fn hash<H: Hasher>(&self, s: &mut H) {
455 (self as *const TyS).hash(s)
459 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for ty::TyS<'tcx> {
460 fn hash_stable<W: StableHasherResult>(&self,
461 hcx: &mut StableHashingContext<'a, 'tcx>,
462 hasher: &mut StableHasher<W>) {
466 // The other fields just provide fast access to information that is
467 // also contained in `sty`, so no need to hash them.
472 sty.hash_stable(hcx, hasher);
476 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
478 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
479 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
481 /// A wrapper for slices with the additional invariant
482 /// that the slice is interned and no other slice with
483 /// the same contents can exist in the same context.
484 /// This means we can use pointer + length for both
485 /// equality comparisons and hashing.
486 #[derive(Debug, RustcEncodable)]
487 pub struct Slice<T>([T]);
489 impl<T> PartialEq for Slice<T> {
491 fn eq(&self, other: &Slice<T>) -> bool {
492 (&self.0 as *const [T]) == (&other.0 as *const [T])
495 impl<T> Eq for Slice<T> {}
497 impl<T> Hash for Slice<T> {
498 fn hash<H: Hasher>(&self, s: &mut H) {
499 (self.as_ptr(), self.len()).hash(s)
503 impl<T> Deref for Slice<T> {
505 fn deref(&self) -> &[T] {
510 impl<'a, T> IntoIterator for &'a Slice<T> {
512 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
513 fn into_iter(self) -> Self::IntoIter {
518 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {}
521 pub fn empty<'a>() -> &'a Slice<T> {
523 mem::transmute(slice::from_raw_parts(0x1 as *const T, 0))
528 /// Upvars do not get their own node-id. Instead, we use the pair of
529 /// the original var id (that is, the root variable that is referenced
530 /// by the upvar) and the id of the closure expression.
531 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
534 pub closure_expr_id: NodeId,
537 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
538 pub enum BorrowKind {
539 /// Data must be immutable and is aliasable.
542 /// Data must be immutable but not aliasable. This kind of borrow
543 /// cannot currently be expressed by the user and is used only in
544 /// implicit closure bindings. It is needed when the closure
545 /// is borrowing or mutating a mutable referent, e.g.:
547 /// let x: &mut isize = ...;
548 /// let y = || *x += 5;
550 /// If we were to try to translate this closure into a more explicit
551 /// form, we'd encounter an error with the code as written:
553 /// struct Env { x: & &mut isize }
554 /// let x: &mut isize = ...;
555 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
556 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
558 /// This is then illegal because you cannot mutate a `&mut` found
559 /// in an aliasable location. To solve, you'd have to translate with
560 /// an `&mut` borrow:
562 /// struct Env { x: & &mut isize }
563 /// let x: &mut isize = ...;
564 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
565 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
567 /// Now the assignment to `**env.x` is legal, but creating a
568 /// mutable pointer to `x` is not because `x` is not mutable. We
569 /// could fix this by declaring `x` as `let mut x`. This is ok in
570 /// user code, if awkward, but extra weird for closures, since the
571 /// borrow is hidden.
573 /// So we introduce a "unique imm" borrow -- the referent is
574 /// immutable, but not aliasable. This solves the problem. For
575 /// simplicity, we don't give users the way to express this
576 /// borrow, it's just used when translating closures.
579 /// Data is mutable and not aliasable.
583 /// Information describing the capture of an upvar. This is computed
584 /// during `typeck`, specifically by `regionck`.
585 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
586 pub enum UpvarCapture<'tcx> {
587 /// Upvar is captured by value. This is always true when the
588 /// closure is labeled `move`, but can also be true in other cases
589 /// depending on inference.
592 /// Upvar is captured by reference.
593 ByRef(UpvarBorrow<'tcx>),
596 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
597 pub struct UpvarBorrow<'tcx> {
598 /// The kind of borrow: by-ref upvars have access to shared
599 /// immutable borrows, which are not part of the normal language
601 pub kind: BorrowKind,
603 /// Region of the resulting reference.
604 pub region: &'tcx ty::Region,
607 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
609 #[derive(Copy, Clone)]
610 pub struct ClosureUpvar<'tcx> {
616 #[derive(Clone, Copy, PartialEq)]
617 pub enum IntVarValue {
619 UintType(ast::UintTy),
622 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
623 pub struct TypeParameterDef {
627 pub has_default: bool,
628 pub object_lifetime_default: ObjectLifetimeDefault,
630 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
631 /// on generic parameter `T`, asserts data behind the parameter
632 /// `T` won't be accessed during the parent type's `Drop` impl.
633 pub pure_wrt_drop: bool,
636 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
637 pub struct RegionParameterDef {
641 pub issue_32330: Option<ty::Issue32330>,
643 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
644 /// on generic parameter `'a`, asserts data of lifetime `'a`
645 /// won't be accessed during the parent type's `Drop` impl.
646 pub pure_wrt_drop: bool,
649 impl RegionParameterDef {
650 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
651 ty::EarlyBoundRegion {
657 pub fn to_bound_region(&self) -> ty::BoundRegion {
658 ty::BoundRegion::BrNamed(self.def_id, self.name)
662 /// Information about the formal type/lifetime parameters associated
663 /// with an item or method. Analogous to hir::Generics.
664 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
665 pub struct Generics {
666 pub parent: Option<DefId>,
667 pub parent_regions: u32,
668 pub parent_types: u32,
669 pub regions: Vec<RegionParameterDef>,
670 pub types: Vec<TypeParameterDef>,
672 /// Reverse map to each `TypeParameterDef`'s `index` field, from
673 /// `def_id.index` (`def_id.krate` is the same as the item's).
674 pub type_param_to_index: BTreeMap<DefIndex, u32>,
680 pub fn parent_count(&self) -> usize {
681 self.parent_regions as usize + self.parent_types as usize
684 pub fn own_count(&self) -> usize {
685 self.regions.len() + self.types.len()
688 pub fn count(&self) -> usize {
689 self.parent_count() + self.own_count()
692 pub fn region_param(&self, param: &EarlyBoundRegion) -> &RegionParameterDef {
693 assert_eq!(self.parent_count(), 0);
694 &self.regions[param.index as usize - self.has_self as usize]
697 pub fn type_param(&self, param: &ParamTy) -> &TypeParameterDef {
698 assert_eq!(self.parent_count(), 0);
699 &self.types[param.idx as usize - self.has_self as usize - self.regions.len()]
703 /// Bounds on generics.
704 #[derive(Clone, Default)]
705 pub struct GenericPredicates<'tcx> {
706 pub parent: Option<DefId>,
707 pub predicates: Vec<Predicate<'tcx>>,
710 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
711 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
713 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
714 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
715 -> InstantiatedPredicates<'tcx> {
716 let mut instantiated = InstantiatedPredicates::empty();
717 self.instantiate_into(tcx, &mut instantiated, substs);
720 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
721 -> InstantiatedPredicates<'tcx> {
722 InstantiatedPredicates {
723 predicates: self.predicates.subst(tcx, substs)
727 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
728 instantiated: &mut InstantiatedPredicates<'tcx>,
729 substs: &Substs<'tcx>) {
730 if let Some(def_id) = self.parent {
731 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
733 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
736 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
737 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
738 -> InstantiatedPredicates<'tcx>
740 assert_eq!(self.parent, None);
741 InstantiatedPredicates {
742 predicates: self.predicates.iter().map(|pred| {
743 pred.subst_supertrait(tcx, poly_trait_ref)
749 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
750 pub enum Predicate<'tcx> {
751 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
752 /// the `Self` type of the trait reference and `A`, `B`, and `C`
753 /// would be the type parameters.
754 Trait(PolyTraitPredicate<'tcx>),
756 /// where `T1 == T2`.
757 Equate(PolyEquatePredicate<'tcx>),
760 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
763 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
765 /// where <T as TraitRef>::Name == X, approximately.
766 /// See `ProjectionPredicate` struct for details.
767 Projection(PolyProjectionPredicate<'tcx>),
770 WellFormed(Ty<'tcx>),
772 /// trait must be object-safe
775 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
776 /// for some substitutions `...` and T being a closure type.
777 /// Satisfied (or refuted) once we know the closure's kind.
778 ClosureKind(DefId, ClosureKind),
781 Subtype(PolySubtypePredicate<'tcx>),
784 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
785 /// Performs a substitution suitable for going from a
786 /// poly-trait-ref to supertraits that must hold if that
787 /// poly-trait-ref holds. This is slightly different from a normal
788 /// substitution in terms of what happens with bound regions. See
789 /// lengthy comment below for details.
790 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
791 trait_ref: &ty::PolyTraitRef<'tcx>)
792 -> ty::Predicate<'tcx>
794 // The interaction between HRTB and supertraits is not entirely
795 // obvious. Let me walk you (and myself) through an example.
797 // Let's start with an easy case. Consider two traits:
799 // trait Foo<'a> : Bar<'a,'a> { }
800 // trait Bar<'b,'c> { }
802 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
803 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
804 // knew that `Foo<'x>` (for any 'x) then we also know that
805 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
806 // normal substitution.
808 // In terms of why this is sound, the idea is that whenever there
809 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
810 // holds. So if there is an impl of `T:Foo<'a>` that applies to
811 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
814 // Another example to be careful of is this:
816 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
817 // trait Bar1<'b,'c> { }
819 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
820 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
821 // reason is similar to the previous example: any impl of
822 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
823 // basically we would want to collapse the bound lifetimes from
824 // the input (`trait_ref`) and the supertraits.
826 // To achieve this in practice is fairly straightforward. Let's
827 // consider the more complicated scenario:
829 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
830 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
831 // where both `'x` and `'b` would have a DB index of 1.
832 // The substitution from the input trait-ref is therefore going to be
833 // `'a => 'x` (where `'x` has a DB index of 1).
834 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
835 // early-bound parameter and `'b' is a late-bound parameter with a
837 // - If we replace `'a` with `'x` from the input, it too will have
838 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
839 // just as we wanted.
841 // There is only one catch. If we just apply the substitution `'a
842 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
843 // adjust the DB index because we substituting into a binder (it
844 // tries to be so smart...) resulting in `for<'x> for<'b>
845 // Bar1<'x,'b>` (we have no syntax for this, so use your
846 // imagination). Basically the 'x will have DB index of 2 and 'b
847 // will have DB index of 1. Not quite what we want. So we apply
848 // the substitution to the *contents* of the trait reference,
849 // rather than the trait reference itself (put another way, the
850 // substitution code expects equal binding levels in the values
851 // from the substitution and the value being substituted into, and
852 // this trick achieves that).
854 let substs = &trait_ref.0.substs;
856 Predicate::Trait(ty::Binder(ref data)) =>
857 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
858 Predicate::Equate(ty::Binder(ref data)) =>
859 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
860 Predicate::Subtype(ty::Binder(ref data)) =>
861 Predicate::Subtype(ty::Binder(data.subst(tcx, substs))),
862 Predicate::RegionOutlives(ty::Binder(ref data)) =>
863 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
864 Predicate::TypeOutlives(ty::Binder(ref data)) =>
865 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
866 Predicate::Projection(ty::Binder(ref data)) =>
867 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
868 Predicate::WellFormed(data) =>
869 Predicate::WellFormed(data.subst(tcx, substs)),
870 Predicate::ObjectSafe(trait_def_id) =>
871 Predicate::ObjectSafe(trait_def_id),
872 Predicate::ClosureKind(closure_def_id, kind) =>
873 Predicate::ClosureKind(closure_def_id, kind),
878 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
879 pub struct TraitPredicate<'tcx> {
880 pub trait_ref: TraitRef<'tcx>
882 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
884 impl<'tcx> TraitPredicate<'tcx> {
885 pub fn def_id(&self) -> DefId {
886 self.trait_ref.def_id
889 /// Creates the dep-node for selecting/evaluating this trait reference.
890 fn dep_node(&self) -> DepNode<DefId> {
891 // Extact the trait-def and first def-id from inputs. See the
892 // docs for `DepNode::TraitSelect` for more information.
893 let trait_def_id = self.def_id();
896 .flat_map(|t| t.walk())
897 .filter_map(|t| match t.sty {
898 ty::TyAdt(adt_def, _) => Some(adt_def.did),
902 .unwrap_or(trait_def_id);
903 DepNode::TraitSelect {
904 trait_def_id: trait_def_id,
905 input_def_id: input_def_id
909 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
910 self.trait_ref.input_types()
913 pub fn self_ty(&self) -> Ty<'tcx> {
914 self.trait_ref.self_ty()
918 impl<'tcx> PolyTraitPredicate<'tcx> {
919 pub fn def_id(&self) -> DefId {
920 // ok to skip binder since trait def-id does not care about regions
924 pub fn dep_node(&self) -> DepNode<DefId> {
925 // ok to skip binder since depnode does not care about regions
930 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
931 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
932 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
934 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
935 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
936 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
937 pub type PolyRegionOutlivesPredicate<'tcx> = PolyOutlivesPredicate<&'tcx ty::Region,
939 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, &'tcx ty::Region>;
941 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
942 pub struct SubtypePredicate<'tcx> {
943 pub a_is_expected: bool,
947 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
949 /// This kind of predicate has no *direct* correspondent in the
950 /// syntax, but it roughly corresponds to the syntactic forms:
952 /// 1. `T : TraitRef<..., Item=Type>`
953 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
955 /// In particular, form #1 is "desugared" to the combination of a
956 /// normal trait predicate (`T : TraitRef<...>`) and one of these
957 /// predicates. Form #2 is a broader form in that it also permits
958 /// equality between arbitrary types. Processing an instance of Form
959 /// #2 eventually yields one of these `ProjectionPredicate`
960 /// instances to normalize the LHS.
961 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
962 pub struct ProjectionPredicate<'tcx> {
963 pub projection_ty: ProjectionTy<'tcx>,
967 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
969 impl<'tcx> PolyProjectionPredicate<'tcx> {
970 pub fn item_name(&self) -> Name {
971 self.0.projection_ty.item_name // safe to skip the binder to access a name
975 pub trait ToPolyTraitRef<'tcx> {
976 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
979 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
980 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
981 assert!(!self.has_escaping_regions());
982 ty::Binder(self.clone())
986 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
987 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
988 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
992 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
993 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
994 // Note: unlike with TraitRef::to_poly_trait_ref(),
995 // self.0.trait_ref is permitted to have escaping regions.
996 // This is because here `self` has a `Binder` and so does our
997 // return value, so we are preserving the number of binding
999 ty::Binder(self.0.projection_ty.trait_ref)
1003 pub trait ToPredicate<'tcx> {
1004 fn to_predicate(&self) -> Predicate<'tcx>;
1007 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1008 fn to_predicate(&self) -> Predicate<'tcx> {
1009 // we're about to add a binder, so let's check that we don't
1010 // accidentally capture anything, or else that might be some
1011 // weird debruijn accounting.
1012 assert!(!self.has_escaping_regions());
1014 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
1015 trait_ref: self.clone()
1020 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1021 fn to_predicate(&self) -> Predicate<'tcx> {
1022 ty::Predicate::Trait(self.to_poly_trait_predicate())
1026 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
1027 fn to_predicate(&self) -> Predicate<'tcx> {
1028 Predicate::Equate(self.clone())
1032 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1033 fn to_predicate(&self) -> Predicate<'tcx> {
1034 Predicate::RegionOutlives(self.clone())
1038 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1039 fn to_predicate(&self) -> Predicate<'tcx> {
1040 Predicate::TypeOutlives(self.clone())
1044 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1045 fn to_predicate(&self) -> Predicate<'tcx> {
1046 Predicate::Projection(self.clone())
1050 impl<'tcx> Predicate<'tcx> {
1051 /// Iterates over the types in this predicate. Note that in all
1052 /// cases this is skipping over a binder, so late-bound regions
1053 /// with depth 0 are bound by the predicate.
1054 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1055 let vec: Vec<_> = match *self {
1056 ty::Predicate::Trait(ref data) => {
1057 data.skip_binder().input_types().collect()
1059 ty::Predicate::Equate(ty::Binder(ref data)) => {
1060 vec![data.0, data.1]
1062 ty::Predicate::Subtype(ty::Binder(SubtypePredicate { a, b, a_is_expected: _ })) => {
1065 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
1068 ty::Predicate::RegionOutlives(..) => {
1071 ty::Predicate::Projection(ref data) => {
1072 let trait_inputs = data.0.projection_ty.trait_ref.input_types();
1073 trait_inputs.chain(Some(data.0.ty)).collect()
1075 ty::Predicate::WellFormed(data) => {
1078 ty::Predicate::ObjectSafe(_trait_def_id) => {
1081 ty::Predicate::ClosureKind(_closure_def_id, _kind) => {
1086 // The only reason to collect into a vector here is that I was
1087 // too lazy to make the full (somewhat complicated) iterator
1088 // type that would be needed here. But I wanted this fn to
1089 // return an iterator conceptually, rather than a `Vec`, so as
1090 // to be closer to `Ty::walk`.
1094 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1096 Predicate::Trait(ref t) => {
1097 Some(t.to_poly_trait_ref())
1099 Predicate::Projection(..) |
1100 Predicate::Equate(..) |
1101 Predicate::Subtype(..) |
1102 Predicate::RegionOutlives(..) |
1103 Predicate::WellFormed(..) |
1104 Predicate::ObjectSafe(..) |
1105 Predicate::ClosureKind(..) |
1106 Predicate::TypeOutlives(..) => {
1113 /// Represents the bounds declared on a particular set of type
1114 /// parameters. Should eventually be generalized into a flag list of
1115 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1116 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1117 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1118 /// the `GenericPredicates` are expressed in terms of the bound type
1119 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1120 /// represented a set of bounds for some particular instantiation,
1121 /// meaning that the generic parameters have been substituted with
1126 /// struct Foo<T,U:Bar<T>> { ... }
1128 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1129 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1130 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1131 /// [usize:Bar<isize>]]`.
1133 pub struct InstantiatedPredicates<'tcx> {
1134 pub predicates: Vec<Predicate<'tcx>>,
1137 impl<'tcx> InstantiatedPredicates<'tcx> {
1138 pub fn empty() -> InstantiatedPredicates<'tcx> {
1139 InstantiatedPredicates { predicates: vec![] }
1142 pub fn is_empty(&self) -> bool {
1143 self.predicates.is_empty()
1147 /// When type checking, we use the `ParameterEnvironment` to track
1148 /// details about the type/lifetime parameters that are in scope.
1149 /// It primarily stores the bounds information.
1151 /// Note: This information might seem to be redundant with the data in
1152 /// `tcx.ty_param_defs`, but it is not. That table contains the
1153 /// parameter definitions from an "outside" perspective, but this
1154 /// struct will contain the bounds for a parameter as seen from inside
1155 /// the function body. Currently the only real distinction is that
1156 /// bound lifetime parameters are replaced with free ones, but in the
1157 /// future I hope to refine the representation of types so as to make
1158 /// more distinctions clearer.
1160 pub struct ParameterEnvironment<'tcx> {
1161 /// See `construct_free_substs` for details.
1162 pub free_substs: &'tcx Substs<'tcx>,
1164 /// Each type parameter has an implicit region bound that
1165 /// indicates it must outlive at least the function body (the user
1166 /// may specify stronger requirements). This field indicates the
1167 /// region of the callee. If it is `None`, then the parameter
1168 /// environment is for an item or something where the "callee" is
1170 pub implicit_region_bound: Option<&'tcx ty::Region>,
1172 /// Obligations that the caller must satisfy. This is basically
1173 /// the set of bounds on the in-scope type parameters, translated
1174 /// into Obligations, and elaborated and normalized.
1175 pub caller_bounds: Vec<ty::Predicate<'tcx>>,
1177 /// Scope that is attached to free regions for this scope. This is
1178 /// usually the id of the fn body, but for more abstract scopes
1179 /// like structs we use None or the item extent.
1181 /// FIXME(#3696). It would be nice to refactor so that free
1182 /// regions don't have this implicit scope and instead introduce
1183 /// relationships in the environment.
1184 pub free_id_outlive: Option<CodeExtent>,
1186 /// A cache for `moves_by_default`.
1187 pub is_copy_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1189 /// A cache for `type_is_sized`
1190 pub is_sized_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1192 /// A cache for `type_is_freeze`
1193 pub is_freeze_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1196 impl<'a, 'tcx> ParameterEnvironment<'tcx> {
1197 pub fn with_caller_bounds(&self,
1198 caller_bounds: Vec<ty::Predicate<'tcx>>)
1199 -> ParameterEnvironment<'tcx>
1201 ParameterEnvironment {
1202 free_substs: self.free_substs,
1203 implicit_region_bound: self.implicit_region_bound,
1204 caller_bounds: caller_bounds,
1205 free_id_outlive: self.free_id_outlive,
1206 is_copy_cache: RefCell::new(FxHashMap()),
1207 is_sized_cache: RefCell::new(FxHashMap()),
1208 is_freeze_cache: RefCell::new(FxHashMap()),
1212 /// Construct a parameter environment given an item, impl item, or trait item
1213 pub fn for_item(tcx: TyCtxt<'a, 'tcx, 'tcx>, id: NodeId)
1214 -> ParameterEnvironment<'tcx> {
1215 match tcx.hir.find(id) {
1216 Some(hir_map::NodeImplItem(ref impl_item)) => {
1217 match impl_item.node {
1218 hir::ImplItemKind::Type(_) | hir::ImplItemKind::Const(..) => {
1219 // associated types don't have their own entry (for some reason),
1220 // so for now just grab environment for the impl
1221 let impl_id = tcx.hir.get_parent(id);
1222 let impl_def_id = tcx.hir.local_def_id(impl_id);
1223 tcx.construct_parameter_environment(impl_item.span,
1225 Some(tcx.region_maps().item_extent(id)))
1227 hir::ImplItemKind::Method(_, ref body) => {
1228 tcx.construct_parameter_environment(
1230 tcx.hir.local_def_id(id),
1231 Some(tcx.region_maps().call_site_extent(id, body.node_id)))
1235 Some(hir_map::NodeTraitItem(trait_item)) => {
1236 match trait_item.node {
1237 hir::TraitItemKind::Type(..) | hir::TraitItemKind::Const(..) => {
1238 // associated types don't have their own entry (for some reason),
1239 // so for now just grab environment for the trait
1240 let trait_id = tcx.hir.get_parent(id);
1241 let trait_def_id = tcx.hir.local_def_id(trait_id);
1242 tcx.construct_parameter_environment(trait_item.span,
1244 Some(tcx.region_maps().item_extent(id)))
1246 hir::TraitItemKind::Method(_, ref body) => {
1247 // Use call-site for extent (unless this is a
1248 // trait method with no default; then fallback
1249 // to the method id).
1250 let extent = if let hir::TraitMethod::Provided(body_id) = *body {
1251 // default impl: use call_site extent as free_id_outlive bound.
1252 tcx.region_maps().call_site_extent(id, body_id.node_id)
1254 // no default impl: use item extent as free_id_outlive bound.
1255 tcx.region_maps().item_extent(id)
1257 tcx.construct_parameter_environment(
1259 tcx.hir.local_def_id(id),
1264 Some(hir_map::NodeItem(item)) => {
1266 hir::ItemFn(.., body_id) => {
1267 // We assume this is a function.
1268 let fn_def_id = tcx.hir.local_def_id(id);
1270 tcx.construct_parameter_environment(
1273 Some(tcx.region_maps().call_site_extent(id, body_id.node_id)))
1276 hir::ItemStruct(..) |
1277 hir::ItemUnion(..) |
1280 hir::ItemConst(..) |
1281 hir::ItemStatic(..) => {
1282 let def_id = tcx.hir.local_def_id(id);
1283 tcx.construct_parameter_environment(item.span,
1285 Some(tcx.region_maps().item_extent(id)))
1287 hir::ItemTrait(..) => {
1288 let def_id = tcx.hir.local_def_id(id);
1289 tcx.construct_parameter_environment(item.span,
1291 Some(tcx.region_maps().item_extent(id)))
1294 span_bug!(item.span,
1295 "ParameterEnvironment::for_item():
1296 can't create a parameter \
1297 environment for this kind of item")
1301 Some(hir_map::NodeExpr(expr)) => {
1302 // This is a convenience to allow closures to work.
1303 if let hir::ExprClosure(.., body, _) = expr.node {
1304 let def_id = tcx.hir.local_def_id(id);
1305 let base_def_id = tcx.closure_base_def_id(def_id);
1306 tcx.construct_parameter_environment(
1309 Some(tcx.region_maps().call_site_extent(id, body.node_id)))
1311 tcx.empty_parameter_environment()
1314 Some(hir_map::NodeForeignItem(item)) => {
1315 let def_id = tcx.hir.local_def_id(id);
1316 tcx.construct_parameter_environment(item.span,
1320 Some(hir_map::NodeStructCtor(..)) |
1321 Some(hir_map::NodeVariant(..)) => {
1322 let def_id = tcx.hir.local_def_id(id);
1323 tcx.construct_parameter_environment(tcx.hir.span(id),
1328 bug!("ParameterEnvironment::from_item(): \
1329 `{}` = {:?} is unsupported",
1330 tcx.hir.node_to_string(id), it)
1336 #[derive(Copy, Clone, Debug)]
1337 pub struct Destructor {
1338 /// The def-id of the destructor method
1343 flags AdtFlags: u32 {
1344 const NO_ADT_FLAGS = 0,
1345 const IS_ENUM = 1 << 0,
1346 const IS_PHANTOM_DATA = 1 << 1,
1347 const IS_FUNDAMENTAL = 1 << 2,
1348 const IS_UNION = 1 << 3,
1349 const IS_BOX = 1 << 4,
1354 pub struct VariantDef {
1355 /// The variant's DefId. If this is a tuple-like struct,
1356 /// this is the DefId of the struct's ctor.
1358 pub name: Name, // struct's name if this is a struct
1359 pub discr: VariantDiscr,
1360 pub fields: Vec<FieldDef>,
1361 pub ctor_kind: CtorKind,
1364 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1365 pub enum VariantDiscr {
1366 /// Explicit value for this variant, i.e. `X = 123`.
1367 /// The `DefId` corresponds to the embedded constant.
1370 /// The previous variant's discriminant plus one.
1371 /// For efficiency reasons, the distance from the
1372 /// last `Explicit` discriminant is being stored,
1373 /// or `0` for the first variant, if it has none.
1378 pub struct FieldDef {
1381 pub vis: Visibility,
1384 /// The definition of an abstract data type - a struct or enum.
1386 /// These are all interned (by intern_adt_def) into the adt_defs
1390 pub variants: Vec<VariantDef>,
1392 pub repr: ReprOptions,
1395 impl PartialEq for AdtDef {
1396 // AdtDef are always interned and this is part of TyS equality
1398 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1401 impl Eq for AdtDef {}
1403 impl Hash for AdtDef {
1405 fn hash<H: Hasher>(&self, s: &mut H) {
1406 (self as *const AdtDef).hash(s)
1410 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1411 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1416 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1419 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for AdtDef {
1420 fn hash_stable<W: StableHasherResult>(&self,
1421 hcx: &mut StableHashingContext<'a, 'tcx>,
1422 hasher: &mut StableHasher<W>) {
1430 did.hash_stable(hcx, hasher);
1431 variants.hash_stable(hcx, hasher);
1432 flags.hash_stable(hcx, hasher);
1433 repr.hash_stable(hcx, hasher);
1437 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1438 pub enum AdtKind { Struct, Union, Enum }
1441 #[derive(RustcEncodable, RustcDecodable, Default)]
1442 flags ReprFlags: u8 {
1443 const IS_C = 1 << 0,
1444 const IS_PACKED = 1 << 1,
1445 const IS_SIMD = 1 << 2,
1446 // Internal only for now. If true, don't reorder fields.
1447 const IS_LINEAR = 1 << 3,
1449 // Any of these flags being set prevent field reordering optimisation.
1450 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1451 ReprFlags::IS_PACKED.bits |
1452 ReprFlags::IS_SIMD.bits |
1453 ReprFlags::IS_LINEAR.bits,
1457 impl_stable_hash_for!(struct ReprFlags {
1463 /// Represents the repr options provided by the user,
1464 #[derive(Copy, Clone, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1465 pub struct ReprOptions {
1466 pub int: Option<attr::IntType>,
1468 pub flags: ReprFlags,
1471 impl_stable_hash_for!(struct ReprOptions {
1478 pub fn new(tcx: TyCtxt, did: DefId) -> ReprOptions {
1479 let mut flags = ReprFlags::empty();
1480 let mut size = None;
1481 let mut max_align = 0;
1482 for attr in tcx.get_attrs(did).iter() {
1483 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1484 flags.insert(match r {
1485 attr::ReprExtern => ReprFlags::IS_C,
1486 attr::ReprPacked => ReprFlags::IS_PACKED,
1487 attr::ReprSimd => ReprFlags::IS_SIMD,
1488 attr::ReprInt(i) => {
1492 attr::ReprAlign(align) => {
1493 max_align = cmp::max(align, max_align);
1500 // FIXME(eddyb) This is deprecated and should be removed.
1501 if tcx.has_attr(did, "simd") {
1502 flags.insert(ReprFlags::IS_SIMD);
1505 // This is here instead of layout because the choice must make it into metadata.
1506 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1507 flags.insert(ReprFlags::IS_LINEAR);
1509 ReprOptions { int: size, align: max_align, flags: flags }
1513 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1515 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1517 pub fn packed(&self) -> bool { self.flags.contains(ReprFlags::IS_PACKED) }
1519 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1521 pub fn discr_type(&self) -> attr::IntType {
1522 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Is))
1525 /// Returns true if this `#[repr()]` should inhabit "smart enum
1526 /// layout" optimizations, such as representing `Foo<&T>` as a
1528 pub fn inhibit_enum_layout_opt(&self) -> bool {
1529 self.c() || self.int.is_some()
1533 impl<'a, 'gcx, 'tcx> AdtDef {
1537 variants: Vec<VariantDef>,
1538 repr: ReprOptions) -> Self {
1539 let mut flags = AdtFlags::NO_ADT_FLAGS;
1540 let attrs = tcx.get_attrs(did);
1541 if attr::contains_name(&attrs, "fundamental") {
1542 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1544 if Some(did) == tcx.lang_items.phantom_data() {
1545 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1547 if Some(did) == tcx.lang_items.owned_box() {
1548 flags = flags | AdtFlags::IS_BOX;
1551 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
1552 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
1553 AdtKind::Struct => {}
1564 pub fn is_struct(&self) -> bool {
1565 !self.is_union() && !self.is_enum()
1569 pub fn is_union(&self) -> bool {
1570 self.flags.intersects(AdtFlags::IS_UNION)
1574 pub fn is_enum(&self) -> bool {
1575 self.flags.intersects(AdtFlags::IS_ENUM)
1578 /// Returns the kind of the ADT - Struct or Enum.
1580 pub fn adt_kind(&self) -> AdtKind {
1583 } else if self.is_union() {
1590 pub fn descr(&self) -> &'static str {
1591 match self.adt_kind() {
1592 AdtKind::Struct => "struct",
1593 AdtKind::Union => "union",
1594 AdtKind::Enum => "enum",
1598 pub fn variant_descr(&self) -> &'static str {
1599 match self.adt_kind() {
1600 AdtKind::Struct => "struct",
1601 AdtKind::Union => "union",
1602 AdtKind::Enum => "variant",
1606 /// Returns whether this type is #[fundamental] for the purposes
1607 /// of coherence checking.
1609 pub fn is_fundamental(&self) -> bool {
1610 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
1613 /// Returns true if this is PhantomData<T>.
1615 pub fn is_phantom_data(&self) -> bool {
1616 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
1619 /// Returns true if this is Box<T>.
1621 pub fn is_box(&self) -> bool {
1622 self.flags.intersects(AdtFlags::IS_BOX)
1625 /// Returns whether this type has a destructor.
1626 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
1627 self.destructor(tcx).is_some()
1630 /// Asserts this is a struct and returns the struct's unique
1632 pub fn struct_variant(&self) -> &VariantDef {
1633 assert!(!self.is_enum());
1638 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
1639 tcx.predicates_of(self.did)
1642 /// Returns an iterator over all fields contained
1645 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
1646 self.variants.iter().flat_map(|v| v.fields.iter())
1650 pub fn is_univariant(&self) -> bool {
1651 self.variants.len() == 1
1654 pub fn is_payloadfree(&self) -> bool {
1655 !self.variants.is_empty() &&
1656 self.variants.iter().all(|v| v.fields.is_empty())
1659 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
1662 .find(|v| v.did == vid)
1663 .expect("variant_with_id: unknown variant")
1666 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1669 .position(|v| v.did == vid)
1670 .expect("variant_index_with_id: unknown variant")
1673 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
1675 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
1676 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
1677 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.struct_variant(),
1678 _ => bug!("unexpected def {:?} in variant_of_def", def)
1683 pub fn discriminants(&'a self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1684 -> impl Iterator<Item=ConstInt> + 'a {
1685 let repr_type = self.repr.discr_type();
1686 let initial = repr_type.initial_discriminant(tcx.global_tcx());
1687 let mut prev_discr = None::<ConstInt>;
1688 self.variants.iter().map(move |v| {
1689 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr());
1690 if let VariantDiscr::Explicit(expr_did) = v.discr {
1691 let substs = Substs::empty();
1692 match tcx.const_eval((expr_did, substs)) {
1693 Ok(ConstVal::Integral(v)) => {
1697 if !expr_did.is_local() {
1698 span_bug!(tcx.def_span(expr_did),
1699 "variant discriminant evaluation succeeded \
1700 in its crate but failed locally: {:?}", err);
1705 prev_discr = Some(discr);
1711 /// Compute the discriminant value used by a specific variant.
1712 /// Unlike `discriminants`, this is (amortized) constant-time,
1713 /// only doing at most one query for evaluating an explicit
1714 /// discriminant (the last one before the requested variant),
1715 /// assuming there are no constant-evaluation errors there.
1716 pub fn discriminant_for_variant(&self,
1717 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1718 variant_index: usize)
1720 let repr_type = self.repr.discr_type();
1721 let mut explicit_value = repr_type.initial_discriminant(tcx.global_tcx());
1722 let mut explicit_index = variant_index;
1724 match self.variants[explicit_index].discr {
1725 ty::VariantDiscr::Relative(0) => break,
1726 ty::VariantDiscr::Relative(distance) => {
1727 explicit_index -= distance;
1729 ty::VariantDiscr::Explicit(expr_did) => {
1730 let substs = Substs::empty();
1731 match tcx.const_eval((expr_did, substs)) {
1732 Ok(ConstVal::Integral(v)) => {
1737 if !expr_did.is_local() {
1738 span_bug!(tcx.def_span(expr_did),
1739 "variant discriminant evaluation succeeded \
1740 in its crate but failed locally: {:?}", err);
1742 if explicit_index == 0 {
1745 explicit_index -= 1;
1751 let discr = explicit_value.to_u128_unchecked()
1752 .wrapping_add((variant_index - explicit_index) as u128);
1754 attr::UnsignedInt(ty) => {
1755 ConstInt::new_unsigned_truncating(discr, ty,
1756 tcx.sess.target.uint_type)
1758 attr::SignedInt(ty) => {
1759 ConstInt::new_signed_truncating(discr as i128, ty,
1760 tcx.sess.target.int_type)
1765 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
1766 tcx.adt_destructor(self.did)
1769 /// Returns a list of types such that `Self: Sized` if and only
1770 /// if that type is Sized, or `TyErr` if this type is recursive.
1772 /// Oddly enough, checking that the sized-constraint is Sized is
1773 /// actually more expressive than checking all members:
1774 /// the Sized trait is inductive, so an associated type that references
1775 /// Self would prevent its containing ADT from being Sized.
1777 /// Due to normalization being eager, this applies even if
1778 /// the associated type is behind a pointer, e.g. issue #31299.
1779 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
1780 match queries::adt_sized_constraint::try_get(tcx, DUMMY_SP, self.did) {
1783 debug!("adt_sized_constraint: {:?} is recursive", self);
1784 // This should be reported as an error by `check_representable`.
1786 // Consider the type as Sized in the meanwhile to avoid
1788 tcx.intern_type_list(&[tcx.types.err])
1793 fn sized_constraint_for_ty(&self,
1794 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1797 let result = match ty.sty {
1798 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
1799 TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
1800 TyArray(..) | TyClosure(..) | TyNever => {
1804 TyStr | TyDynamic(..) | TySlice(_) | TyError => {
1805 // these are never sized - return the target type
1809 TyTuple(ref tys, _) => {
1812 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
1816 TyAdt(adt, substs) => {
1818 let adt_tys = adt.sized_constraint(tcx);
1819 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
1822 .map(|ty| ty.subst(tcx, substs))
1823 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
1827 TyProjection(..) | TyAnon(..) => {
1828 // must calculate explicitly.
1829 // FIXME: consider special-casing always-Sized projections
1834 // perf hack: if there is a `T: Sized` bound, then
1835 // we know that `T` is Sized and do not need to check
1838 let sized_trait = match tcx.lang_items.sized_trait() {
1840 _ => return vec![ty]
1842 let sized_predicate = Binder(TraitRef {
1843 def_id: sized_trait,
1844 substs: tcx.mk_substs_trait(ty, &[])
1846 let predicates = tcx.predicates_of(self.did).predicates;
1847 if predicates.into_iter().any(|p| p == sized_predicate) {
1855 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
1859 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
1864 impl<'a, 'gcx, 'tcx> VariantDef {
1866 pub fn find_field_named(&self,
1868 -> Option<&FieldDef> {
1869 self.fields.iter().find(|f| f.name == name)
1873 pub fn index_of_field_named(&self,
1876 self.fields.iter().position(|f| f.name == name)
1880 pub fn field_named(&self, name: ast::Name) -> &FieldDef {
1881 self.find_field_named(name).unwrap()
1885 impl<'a, 'gcx, 'tcx> FieldDef {
1886 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1887 tcx.type_of(self.did).subst(tcx, subst)
1891 /// Records the substitutions used to translate the polytype for an
1892 /// item into the monotype of an item reference.
1893 #[derive(Clone, RustcEncodable, RustcDecodable)]
1894 pub struct ItemSubsts<'tcx> {
1895 pub substs: &'tcx Substs<'tcx>,
1898 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1899 pub enum ClosureKind {
1900 // Warning: Ordering is significant here! The ordering is chosen
1901 // because the trait Fn is a subtrait of FnMut and so in turn, and
1902 // hence we order it so that Fn < FnMut < FnOnce.
1908 impl<'a, 'tcx> ClosureKind {
1909 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
1911 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
1912 ClosureKind::FnMut => {
1913 tcx.require_lang_item(FnMutTraitLangItem)
1915 ClosureKind::FnOnce => {
1916 tcx.require_lang_item(FnOnceTraitLangItem)
1921 /// True if this a type that impls this closure kind
1922 /// must also implement `other`.
1923 pub fn extends(self, other: ty::ClosureKind) -> bool {
1924 match (self, other) {
1925 (ClosureKind::Fn, ClosureKind::Fn) => true,
1926 (ClosureKind::Fn, ClosureKind::FnMut) => true,
1927 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
1928 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
1929 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
1930 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
1936 impl<'tcx> TyS<'tcx> {
1937 /// Iterator that walks `self` and any types reachable from
1938 /// `self`, in depth-first order. Note that just walks the types
1939 /// that appear in `self`, it does not descend into the fields of
1940 /// structs or variants. For example:
1943 /// isize => { isize }
1944 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
1945 /// [isize] => { [isize], isize }
1947 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
1948 TypeWalker::new(self)
1951 /// Iterator that walks the immediate children of `self`. Hence
1952 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
1953 /// (but not `i32`, like `walk`).
1954 pub fn walk_shallow(&'tcx self) -> AccIntoIter<walk::TypeWalkerArray<'tcx>> {
1955 walk::walk_shallow(self)
1958 /// Walks `ty` and any types appearing within `ty`, invoking the
1959 /// callback `f` on each type. If the callback returns false, then the
1960 /// children of the current type are ignored.
1962 /// Note: prefer `ty.walk()` where possible.
1963 pub fn maybe_walk<F>(&'tcx self, mut f: F)
1964 where F : FnMut(Ty<'tcx>) -> bool
1966 let mut walker = self.walk();
1967 while let Some(ty) = walker.next() {
1969 walker.skip_current_subtree();
1975 impl<'tcx> ItemSubsts<'tcx> {
1976 pub fn is_noop(&self) -> bool {
1977 self.substs.is_noop()
1981 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1982 pub enum LvaluePreference {
1987 impl LvaluePreference {
1988 pub fn from_mutbl(m: hir::Mutability) -> Self {
1990 hir::MutMutable => PreferMutLvalue,
1991 hir::MutImmutable => NoPreference,
1997 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
1999 hir::MutMutable => MutBorrow,
2000 hir::MutImmutable => ImmBorrow,
2004 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2005 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2006 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2008 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2010 MutBorrow => hir::MutMutable,
2011 ImmBorrow => hir::MutImmutable,
2013 // We have no type corresponding to a unique imm borrow, so
2014 // use `&mut`. It gives all the capabilities of an `&uniq`
2015 // and hence is a safe "over approximation".
2016 UniqueImmBorrow => hir::MutMutable,
2020 pub fn to_user_str(&self) -> &'static str {
2022 MutBorrow => "mutable",
2023 ImmBorrow => "immutable",
2024 UniqueImmBorrow => "uniquely immutable",
2029 #[derive(Debug, Clone)]
2030 pub enum Attributes<'gcx> {
2031 Owned(Rc<[ast::Attribute]>),
2032 Borrowed(&'gcx [ast::Attribute])
2035 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2036 type Target = [ast::Attribute];
2038 fn deref(&self) -> &[ast::Attribute] {
2040 &Attributes::Owned(ref data) => &data,
2041 &Attributes::Borrowed(data) => data
2046 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2047 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2048 self.typeck_tables_of(self.hir.body_owner_def_id(body))
2051 pub fn expr_span(self, id: NodeId) -> Span {
2052 match self.hir.find(id) {
2053 Some(hir_map::NodeExpr(e)) => {
2057 bug!("Node id {} is not an expr: {:?}", id, f);
2060 bug!("Node id {} is not present in the node map", id);
2065 pub fn local_var_name_str(self, id: NodeId) -> InternedString {
2066 match self.hir.find(id) {
2067 Some(hir_map::NodeLocal(pat)) => {
2069 hir::PatKind::Binding(_, _, ref path1, _) => path1.node.as_str(),
2071 bug!("Variable id {} maps to {:?}, not local", id, pat);
2075 r => bug!("Variable id {} maps to {:?}, not local", id, r),
2079 pub fn expr_is_lval(self, expr: &hir::Expr) -> bool {
2081 hir::ExprPath(hir::QPath::Resolved(_, ref path)) => {
2083 Def::Local(..) | Def::Upvar(..) | Def::Static(..) | Def::Err => true,
2088 hir::ExprType(ref e, _) => {
2089 self.expr_is_lval(e)
2092 hir::ExprUnary(hir::UnDeref, _) |
2093 hir::ExprField(..) |
2094 hir::ExprTupField(..) |
2095 hir::ExprIndex(..) => {
2099 // Partially qualified paths in expressions can only legally
2100 // refer to associated items which are always rvalues.
2101 hir::ExprPath(hir::QPath::TypeRelative(..)) |
2104 hir::ExprMethodCall(..) |
2105 hir::ExprStruct(..) |
2108 hir::ExprMatch(..) |
2109 hir::ExprClosure(..) |
2110 hir::ExprBlock(..) |
2111 hir::ExprRepeat(..) |
2112 hir::ExprArray(..) |
2113 hir::ExprBreak(..) |
2114 hir::ExprAgain(..) |
2116 hir::ExprWhile(..) |
2118 hir::ExprAssign(..) |
2119 hir::ExprInlineAsm(..) |
2120 hir::ExprAssignOp(..) |
2122 hir::ExprUnary(..) |
2124 hir::ExprAddrOf(..) |
2125 hir::ExprBinary(..) |
2126 hir::ExprCast(..) => {
2132 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2133 self.associated_items(id)
2134 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2138 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2139 self.associated_items(did).any(|item| {
2140 item.relevant_for_never()
2144 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2145 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2146 match self.hir.get(node_id) {
2147 hir_map::NodeTraitItem(_) | hir_map::NodeImplItem(_) => true,
2151 match self.describe_def(def_id).expect("no def for def-id") {
2152 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2157 if is_associated_item {
2158 Some(self.associated_item(def_id))
2164 fn associated_item_from_trait_item_ref(self,
2165 parent_def_id: DefId,
2166 parent_vis: &hir::Visibility,
2167 trait_item_ref: &hir::TraitItemRef)
2169 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2170 let (kind, has_self) = match trait_item_ref.kind {
2171 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2172 hir::AssociatedItemKind::Method { has_self } => {
2173 (ty::AssociatedKind::Method, has_self)
2175 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2179 name: trait_item_ref.name,
2181 // Visibility of trait items is inherited from their traits.
2182 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2183 defaultness: trait_item_ref.defaultness,
2185 container: TraitContainer(parent_def_id),
2186 method_has_self_argument: has_self
2190 fn associated_item_from_impl_item_ref(self,
2191 parent_def_id: DefId,
2192 impl_item_ref: &hir::ImplItemRef)
2194 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2195 let (kind, has_self) = match impl_item_ref.kind {
2196 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2197 hir::AssociatedItemKind::Method { has_self } => {
2198 (ty::AssociatedKind::Method, has_self)
2200 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2203 ty::AssociatedItem {
2204 name: impl_item_ref.name,
2206 // Visibility of trait impl items doesn't matter.
2207 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2208 defaultness: impl_item_ref.defaultness,
2210 container: ImplContainer(parent_def_id),
2211 method_has_self_argument: has_self
2215 #[inline] // FIXME(#35870) Avoid closures being unexported due to impl Trait.
2216 pub fn associated_items(self, def_id: DefId)
2217 -> impl Iterator<Item = ty::AssociatedItem> + 'a {
2218 let def_ids = self.associated_item_def_ids(def_id);
2219 (0..def_ids.len()).map(move |i| self.associated_item(def_ids[i]))
2222 /// Returns true if the impls are the same polarity and are implementing
2223 /// a trait which contains no items
2224 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2225 if !self.sess.features.borrow().overlapping_marker_traits {
2228 let trait1_is_empty = self.impl_trait_ref(def_id1)
2229 .map_or(false, |trait_ref| {
2230 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2232 let trait2_is_empty = self.impl_trait_ref(def_id2)
2233 .map_or(false, |trait_ref| {
2234 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2236 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2241 // Returns `ty::VariantDef` if `def` refers to a struct,
2242 // or variant or their constructors, panics otherwise.
2243 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2245 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2246 let enum_did = self.parent_def_id(did).unwrap();
2247 self.adt_def(enum_did).variant_with_id(did)
2249 Def::Struct(did) | Def::Union(did) => {
2250 self.adt_def(did).struct_variant()
2252 Def::StructCtor(ctor_did, ..) => {
2253 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2254 self.adt_def(did).struct_variant()
2256 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2260 pub fn def_key(self, id: DefId) -> hir_map::DefKey {
2262 self.hir.def_key(id)
2264 self.sess.cstore.def_key(id)
2268 /// Convert a `DefId` into its fully expanded `DefPath` (every
2269 /// `DefId` is really just an interned def-path).
2271 /// Note that if `id` is not local to this crate, the result will
2272 /// be a non-local `DefPath`.
2273 pub fn def_path(self, id: DefId) -> hir_map::DefPath {
2275 self.hir.def_path(id)
2277 self.sess.cstore.def_path(id)
2282 pub fn def_path_hash(self, def_id: DefId) -> u64 {
2283 if def_id.is_local() {
2284 self.hir.definitions().def_path_hash(def_id.index)
2286 self.sess.cstore.def_path_hash(def_id)
2290 pub fn vis_is_accessible_from(self, vis: Visibility, block: NodeId) -> bool {
2291 vis.is_accessible_from(self.hir.local_def_id(self.hir.get_module_parent(block)), self)
2294 pub fn item_name(self, id: DefId) -> ast::Name {
2295 if let Some(id) = self.hir.as_local_node_id(id) {
2297 } else if id.index == CRATE_DEF_INDEX {
2298 self.sess.cstore.original_crate_name(id.krate)
2300 let def_key = self.sess.cstore.def_key(id);
2301 // The name of a StructCtor is that of its struct parent.
2302 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2303 self.item_name(DefId {
2305 index: def_key.parent.unwrap()
2308 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2309 bug!("item_name: no name for {:?}", self.def_path(id));
2315 /// Given the did of an item, returns its MIR, borrowed immutably.
2316 pub fn item_mir(self, did: DefId) -> Ref<'gcx, Mir<'gcx>> {
2317 self.mir(did).borrow()
2320 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2321 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2322 -> Ref<'gcx, Mir<'gcx>>
2325 ty::InstanceDef::Item(did) if true => self.item_mir(did),
2326 _ => self.mir_shims(instance).borrow(),
2330 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2331 /// Returns None if there is no MIR for the DefId
2332 pub fn maybe_item_mir(self, did: DefId) -> Option<Ref<'gcx, Mir<'gcx>>> {
2333 if did.is_local() && !self.maps.mir.borrow().contains_key(&did) {
2337 if !did.is_local() && !self.sess.cstore.is_item_mir_available(did) {
2341 Some(self.item_mir(did))
2344 /// Get the attributes of a definition.
2345 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2346 if let Some(id) = self.hir.as_local_node_id(did) {
2347 Attributes::Borrowed(self.hir.attrs(id))
2349 Attributes::Owned(self.sess.cstore.item_attrs(did))
2353 /// Determine whether an item is annotated with an attribute
2354 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2355 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2358 pub fn trait_has_default_impl(self, trait_def_id: DefId) -> bool {
2359 let def = self.trait_def(trait_def_id);
2360 def.flags.get().intersects(TraitFlags::HAS_DEFAULT_IMPL)
2363 /// Populates the type context with all the implementations for the given
2364 /// trait if necessary.
2365 pub fn populate_implementations_for_trait_if_necessary(self, trait_id: DefId) {
2366 if trait_id.is_local() {
2370 // The type is not local, hence we are reading this out of
2371 // metadata and don't need to track edges.
2372 let _ignore = self.dep_graph.in_ignore();
2374 let def = self.trait_def(trait_id);
2375 if def.flags.get().intersects(TraitFlags::HAS_REMOTE_IMPLS) {
2379 debug!("populate_implementations_for_trait_if_necessary: searching for {:?}", def);
2381 for impl_def_id in self.sess.cstore.implementations_of_trait(Some(trait_id)) {
2382 let trait_ref = self.impl_trait_ref(impl_def_id).unwrap();
2384 // Record the trait->implementation mapping.
2385 let parent = self.sess.cstore.impl_parent(impl_def_id).unwrap_or(trait_id);
2386 def.record_remote_impl(self, impl_def_id, trait_ref, parent);
2389 def.flags.set(def.flags.get() | TraitFlags::HAS_REMOTE_IMPLS);
2392 /// Given the def_id of an impl, return the def_id of the trait it implements.
2393 /// If it implements no trait, return `None`.
2394 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2395 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2398 /// If the given def ID describes a method belonging to an impl, return the
2399 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2400 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2401 let item = if def_id.krate != LOCAL_CRATE {
2402 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2403 Some(self.associated_item(def_id))
2408 self.opt_associated_item(def_id)
2412 Some(trait_item) => {
2413 match trait_item.container {
2414 TraitContainer(_) => None,
2415 ImplContainer(def_id) => Some(def_id),
2422 /// If the given def ID describes an item belonging to a trait,
2423 /// return the ID of the trait that the trait item belongs to.
2424 /// Otherwise, return `None`.
2425 pub fn trait_of_item(self, def_id: DefId) -> Option<DefId> {
2426 if def_id.krate != LOCAL_CRATE {
2427 return self.sess.cstore.trait_of_item(def_id);
2429 self.opt_associated_item(def_id)
2430 .and_then(|associated_item| {
2431 match associated_item.container {
2432 TraitContainer(def_id) => Some(def_id),
2433 ImplContainer(_) => None
2438 /// Construct a parameter environment suitable for static contexts or other contexts where there
2439 /// are no free type/lifetime parameters in scope.
2440 pub fn empty_parameter_environment(self) -> ParameterEnvironment<'tcx> {
2441 ty::ParameterEnvironment {
2442 free_substs: self.intern_substs(&[]),
2443 caller_bounds: Vec::new(),
2444 implicit_region_bound: None,
2445 free_id_outlive: None,
2446 is_copy_cache: RefCell::new(FxHashMap()),
2447 is_sized_cache: RefCell::new(FxHashMap()),
2448 is_freeze_cache: RefCell::new(FxHashMap()),
2452 /// Constructs and returns a substitution that can be applied to move from
2453 /// the "outer" view of a type or method to the "inner" view.
2454 /// In general, this means converting from bound parameters to
2455 /// free parameters. Since we currently represent bound/free type
2456 /// parameters in the same way, this only has an effect on regions.
2457 pub fn construct_free_substs(self, def_id: DefId,
2458 free_id_outlive: Option<CodeExtent>)
2459 -> &'gcx Substs<'gcx> {
2461 let substs = Substs::for_item(self.global_tcx(), def_id, |def, _| {
2462 // map bound 'a => free 'a
2463 self.global_tcx().mk_region(ReFree(FreeRegion {
2464 scope: free_id_outlive,
2465 bound_region: def.to_bound_region()
2469 self.global_tcx().mk_param_from_def(def)
2472 debug!("construct_parameter_environment: {:?}", substs);
2476 /// See `ParameterEnvironment` struct def'n for details.
2477 /// If you were using `free_id: NodeId`, you might try `self.region_maps().item_extent(free_id)`
2478 /// for the `free_id_outlive` parameter. (But note that this is not always quite right.)
2479 pub fn construct_parameter_environment(self,
2482 free_id_outlive: Option<CodeExtent>)
2483 -> ParameterEnvironment<'gcx>
2486 // Construct the free substs.
2489 let free_substs = self.construct_free_substs(def_id, free_id_outlive);
2492 // Compute the bounds on Self and the type parameters.
2495 let tcx = self.global_tcx();
2496 let generic_predicates = tcx.predicates_of(def_id);
2497 let bounds = generic_predicates.instantiate(tcx, free_substs);
2498 let bounds = tcx.liberate_late_bound_regions(free_id_outlive, &ty::Binder(bounds));
2499 let predicates = bounds.predicates;
2501 // Finally, we have to normalize the bounds in the environment, in
2502 // case they contain any associated type projections. This process
2503 // can yield errors if the put in illegal associated types, like
2504 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2505 // report these errors right here; this doesn't actually feel
2506 // right to me, because constructing the environment feels like a
2507 // kind of a "idempotent" action, but I'm not sure where would be
2508 // a better place. In practice, we construct environments for
2509 // every fn once during type checking, and we'll abort if there
2510 // are any errors at that point, so after type checking you can be
2511 // sure that this will succeed without errors anyway.
2514 let unnormalized_env = ty::ParameterEnvironment {
2515 free_substs: free_substs,
2516 implicit_region_bound: free_id_outlive.map(|f| tcx.mk_region(ty::ReScope(f))),
2517 caller_bounds: predicates,
2518 free_id_outlive: free_id_outlive,
2519 is_copy_cache: RefCell::new(FxHashMap()),
2520 is_sized_cache: RefCell::new(FxHashMap()),
2521 is_freeze_cache: RefCell::new(FxHashMap()),
2524 let body_id = free_id_outlive.map(|f| f.node_id(&self.region_maps()))
2525 .unwrap_or(DUMMY_NODE_ID);
2526 let cause = traits::ObligationCause::misc(span, body_id);
2527 traits::normalize_param_env_or_error(tcx, unnormalized_env, cause)
2530 pub fn node_scope_region(self, id: NodeId) -> &'tcx Region {
2531 self.mk_region(ty::ReScope(self.region_maps().node_extent(id)))
2534 pub fn visit_all_item_likes_in_krate<V,F>(self,
2537 where F: FnMut(DefId) -> DepNode<DefId>, V: ItemLikeVisitor<'gcx>
2539 dep_graph::visit_all_item_likes_in_krate(self.global_tcx(), dep_node_fn, visitor);
2542 /// Invokes `callback` for each body in the krate. This will
2543 /// create a read edge from `DepNode::Krate` to the current task;
2544 /// it is meant to be run in the context of some global task like
2545 /// `BorrowckCrate`. The callback would then create a task like
2546 /// `BorrowckBody(DefId)` to process each individual item.
2547 pub fn visit_all_bodies_in_krate<C>(self, callback: C)
2548 where C: Fn(/* body_owner */ DefId, /* body id */ hir::BodyId),
2550 dep_graph::visit_all_bodies_in_krate(self.global_tcx(), callback)
2553 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2554 /// with the name of the crate containing the impl.
2555 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2556 if impl_did.is_local() {
2557 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2558 Ok(self.hir.span(node_id))
2560 Err(self.sess.cstore.crate_name(impl_did.krate))
2565 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2566 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2567 F: FnOnce(&[hir::Freevar]) -> T,
2569 match self.freevars.borrow().get(&fid) {
2571 Some(d) => f(&d[..])
2576 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
2579 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2580 let parent_id = tcx.hir.get_parent(id);
2581 let parent_def_id = tcx.hir.local_def_id(parent_id);
2582 let parent_item = tcx.hir.expect_item(parent_id);
2583 match parent_item.node {
2584 hir::ItemImpl(.., ref impl_item_refs) => {
2585 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2586 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2588 debug_assert_eq!(assoc_item.def_id, def_id);
2593 hir::ItemTrait(.., ref trait_item_refs) => {
2594 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2595 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2598 debug_assert_eq!(assoc_item.def_id, def_id);
2606 span_bug!(parent_item.span,
2607 "unexpected parent of trait or impl item or item not found: {:?}",
2611 /// Calculates the Sized-constraint.
2613 /// In fact, there are only a few options for the types in the constraint:
2614 /// - an obviously-unsized type
2615 /// - a type parameter or projection whose Sizedness can't be known
2616 /// - a tuple of type parameters or projections, if there are multiple
2618 /// - a TyError, if a type contained itself. The representability
2619 /// check should catch this case.
2620 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2622 -> &'tcx [Ty<'tcx>] {
2623 let def = tcx.adt_def(def_id);
2625 let result = tcx.intern_type_list(&def.variants.iter().flat_map(|v| {
2628 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2629 }).collect::<Vec<_>>());
2631 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2636 /// Calculates the dtorck constraint for a type.
2637 fn adt_dtorck_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2639 -> DtorckConstraint<'tcx> {
2640 let def = tcx.adt_def(def_id);
2641 let span = tcx.def_span(def_id);
2642 debug!("dtorck_constraint: {:?}", def);
2644 if def.is_phantom_data() {
2645 let result = DtorckConstraint {
2648 tcx.mk_param_from_def(&tcx.generics_of(def_id).types[0])
2651 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2655 let mut result = def.all_fields()
2656 .map(|field| tcx.type_of(field.did))
2657 .map(|fty| tcx.dtorck_constraint_for_ty(span, fty, 0, fty))
2658 .collect::<Result<DtorckConstraint, ErrorReported>>()
2659 .unwrap_or(DtorckConstraint::empty());
2660 result.outlives.extend(tcx.destructor_constraints(def));
2663 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2668 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2671 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2672 let item = tcx.hir.expect_item(id);
2673 let vec: Vec<_> = match item.node {
2674 hir::ItemTrait(.., ref trait_item_refs) => {
2675 trait_item_refs.iter()
2676 .map(|trait_item_ref| trait_item_ref.id)
2677 .map(|id| tcx.hir.local_def_id(id.node_id))
2680 hir::ItemImpl(.., ref impl_item_refs) => {
2681 impl_item_refs.iter()
2682 .map(|impl_item_ref| impl_item_ref.id)
2683 .map(|id| tcx.hir.local_def_id(id.node_id))
2686 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2691 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
2692 tcx.hir.span_if_local(def_id).unwrap()
2695 pub fn provide(providers: &mut ty::maps::Providers) {
2696 *providers = ty::maps::Providers {
2698 associated_item_def_ids,
2699 adt_sized_constraint,
2700 adt_dtorck_constraint,
2706 pub fn provide_extern(providers: &mut ty::maps::Providers) {
2707 *providers = ty::maps::Providers {
2708 adt_sized_constraint,
2709 adt_dtorck_constraint,
2715 /// A map for the local crate mapping each type to a vector of its
2716 /// inherent impls. This is not meant to be used outside of coherence;
2717 /// rather, you should request the vector for a specific type via
2718 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2719 /// (constructing this map requires touching the entire crate).
2720 #[derive(Clone, Debug)]
2721 pub struct CrateInherentImpls {
2722 pub inherent_impls: DefIdMap<Rc<Vec<DefId>>>,
2725 /// A set of constraints that need to be satisfied in order for
2726 /// a type to be valid for destruction.
2727 #[derive(Clone, Debug)]
2728 pub struct DtorckConstraint<'tcx> {
2729 /// Types that are required to be alive in order for this
2730 /// type to be valid for destruction.
2731 pub outlives: Vec<ty::subst::Kind<'tcx>>,
2732 /// Types that could not be resolved: projections and params.
2733 pub dtorck_types: Vec<Ty<'tcx>>,
2736 impl<'tcx> FromIterator<DtorckConstraint<'tcx>> for DtorckConstraint<'tcx>
2738 fn from_iter<I: IntoIterator<Item=DtorckConstraint<'tcx>>>(iter: I) -> Self {
2739 let mut result = Self::empty();
2741 for constraint in iter {
2742 result.outlives.extend(constraint.outlives);
2743 result.dtorck_types.extend(constraint.dtorck_types);
2751 impl<'tcx> DtorckConstraint<'tcx> {
2752 fn empty() -> DtorckConstraint<'tcx> {
2755 dtorck_types: vec![]
2759 fn dedup<'a>(&mut self) {
2760 let mut outlives = FxHashSet();
2761 let mut dtorck_types = FxHashSet();
2763 self.outlives.retain(|&val| outlives.replace(val).is_none());
2764 self.dtorck_types.retain(|&val| dtorck_types.replace(val).is_none());
2768 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord)]
2769 pub struct SymbolName {
2770 // FIXME: we don't rely on interning or equality here - better have
2771 // this be a `&'tcx str`.
2772 pub name: InternedString
2775 impl Deref for SymbolName {
2778 fn deref(&self) -> &str { &self.name }
2781 impl fmt::Display for SymbolName {
2782 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2783 fmt::Display::fmt(&self.name, fmt)