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::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};
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,
58 use rustc_data_structures::transitive_relation::TransitiveRelation;
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;
109 mod structural_impls;
114 /// The complete set of all analyses described in this module. This is
115 /// produced by the driver and fed to trans and later passes.
117 /// NB: These contents are being migrated into queries using the
118 /// *on-demand* infrastructure.
120 pub struct CrateAnalysis {
121 pub access_levels: Rc<AccessLevels>,
122 pub reachable: Rc<NodeSet>,
124 pub glob_map: Option<hir::GlobMap>,
128 pub struct Resolutions {
129 pub freevars: FreevarMap,
130 pub trait_map: TraitMap,
131 pub maybe_unused_trait_imports: NodeSet,
132 pub export_map: ExportMap,
135 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
136 pub enum AssociatedItemContainer {
137 TraitContainer(DefId),
138 ImplContainer(DefId),
141 impl AssociatedItemContainer {
142 pub fn id(&self) -> DefId {
144 TraitContainer(id) => id,
145 ImplContainer(id) => id,
150 /// The "header" of an impl is everything outside the body: a Self type, a trait
151 /// ref (in the case of a trait impl), and a set of predicates (from the
152 /// bounds/where clauses).
153 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
154 pub struct ImplHeader<'tcx> {
155 pub impl_def_id: DefId,
156 pub self_ty: Ty<'tcx>,
157 pub trait_ref: Option<TraitRef<'tcx>>,
158 pub predicates: Vec<Predicate<'tcx>>,
161 impl<'a, 'gcx, 'tcx> ImplHeader<'tcx> {
162 pub fn with_fresh_ty_vars(selcx: &mut traits::SelectionContext<'a, 'gcx, 'tcx>,
166 let tcx = selcx.tcx();
167 let impl_substs = selcx.infcx().fresh_substs_for_item(DUMMY_SP, impl_def_id);
169 let header = ImplHeader {
170 impl_def_id: impl_def_id,
171 self_ty: tcx.type_of(impl_def_id),
172 trait_ref: tcx.impl_trait_ref(impl_def_id),
173 predicates: tcx.predicates_of(impl_def_id).predicates
174 }.subst(tcx, impl_substs);
176 let traits::Normalized { value: mut header, obligations } =
177 traits::normalize(selcx, traits::ObligationCause::dummy(), &header);
179 header.predicates.extend(obligations.into_iter().map(|o| o.predicate));
184 #[derive(Copy, Clone, Debug)]
185 pub struct AssociatedItem {
188 pub kind: AssociatedKind,
190 pub defaultness: hir::Defaultness,
191 pub container: AssociatedItemContainer,
193 /// Whether this is a method with an explicit self
194 /// as its first argument, allowing method calls.
195 pub method_has_self_argument: bool,
198 #[derive(Copy, Clone, PartialEq, Eq, Debug, RustcEncodable, RustcDecodable)]
199 pub enum AssociatedKind {
205 impl AssociatedItem {
206 pub fn def(&self) -> Def {
208 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
209 AssociatedKind::Method => Def::Method(self.def_id),
210 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
214 /// Tests whether the associated item admits a non-trivial implementation
216 pub fn relevant_for_never<'tcx>(&self) -> bool {
218 AssociatedKind::Const => true,
219 AssociatedKind::Type => true,
220 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
221 AssociatedKind::Method => !self.method_has_self_argument,
226 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
227 pub enum Visibility {
228 /// Visible everywhere (including in other crates).
230 /// Visible only in the given crate-local module.
232 /// Not visible anywhere in the local crate. This is the visibility of private external items.
236 pub trait DefIdTree: Copy {
237 fn parent(self, id: DefId) -> Option<DefId>;
239 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
240 if descendant.krate != ancestor.krate {
244 while descendant != ancestor {
245 match self.parent(descendant) {
246 Some(parent) => descendant = parent,
247 None => return false,
254 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
255 fn parent(self, id: DefId) -> Option<DefId> {
256 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
261 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt) -> Self {
263 hir::Public => Visibility::Public,
264 hir::Visibility::Crate => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
265 hir::Visibility::Restricted { ref path, .. } => match path.def {
266 // If there is no resolution, `resolve` will have already reported an error, so
267 // assume that the visibility is public to avoid reporting more privacy errors.
268 Def::Err => Visibility::Public,
269 def => Visibility::Restricted(def.def_id()),
272 Visibility::Restricted(tcx.hir.local_def_id(tcx.hir.get_module_parent(id)))
277 /// Returns true if an item with this visibility is accessible from the given block.
278 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
279 let restriction = match self {
280 // Public items are visible everywhere.
281 Visibility::Public => return true,
282 // Private items from other crates are visible nowhere.
283 Visibility::Invisible => return false,
284 // Restricted items are visible in an arbitrary local module.
285 Visibility::Restricted(other) if other.krate != module.krate => return false,
286 Visibility::Restricted(module) => module,
289 tree.is_descendant_of(module, restriction)
292 /// Returns true if this visibility is at least as accessible as the given visibility
293 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
294 let vis_restriction = match vis {
295 Visibility::Public => return self == Visibility::Public,
296 Visibility::Invisible => return true,
297 Visibility::Restricted(module) => module,
300 self.is_accessible_from(vis_restriction, tree)
304 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
306 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
307 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
308 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
309 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
312 /// The crate variances map is computed during typeck and contains the
313 /// variance of every item in the local crate. You should not use it
314 /// directly, because to do so will make your pass dependent on the
315 /// HIR of every item in the local crate. Instead, use
316 /// `tcx.variances_of()` to get the variance for a *particular*
318 pub struct CrateVariancesMap {
319 /// This relation tracks the dependencies between the variance of
320 /// various items. In particular, if `a < b`, then the variance of
321 /// `a` depends on the sources of `b`.
322 pub dependencies: TransitiveRelation<DefId>,
324 /// For each item with generics, maps to a vector of the variance
325 /// of its generics. If an item has no generics, it will have no
327 pub variances: FxHashMap<DefId, Rc<Vec<ty::Variance>>>,
329 /// An empty vector, useful for cloning.
330 pub empty_variance: Rc<Vec<ty::Variance>>,
333 #[derive(Clone, Copy, Debug, RustcDecodable, RustcEncodable)]
334 pub struct MethodCallee<'tcx> {
335 /// Impl method ID, for inherent methods, or trait method ID, otherwise.
338 pub substs: &'tcx Substs<'tcx>
341 /// With method calls, we store some extra information in
342 /// side tables (i.e method_map). We use
343 /// MethodCall as a key to index into these tables instead of
344 /// just directly using the expression's NodeId. The reason
345 /// for this being that we may apply adjustments (coercions)
346 /// with the resulting expression also needing to use the
347 /// side tables. The problem with this is that we don't
348 /// assign a separate NodeId to this new expression
349 /// and so it would clash with the base expression if both
350 /// needed to add to the side tables. Thus to disambiguate
351 /// we also keep track of whether there's an adjustment in
353 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
354 pub struct MethodCall {
360 pub fn expr(id: NodeId) -> MethodCall {
367 pub fn autoderef(expr_id: NodeId, autoderef: u32) -> MethodCall {
370 autoderef: 1 + autoderef
375 // maps from an expression id that corresponds to a method call to the details
376 // of the method to be invoked
377 pub type MethodMap<'tcx> = FxHashMap<MethodCall, MethodCallee<'tcx>>;
379 // Contains information needed to resolve types and (in the future) look up
380 // the types of AST nodes.
381 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
382 pub struct CReaderCacheKey {
387 /// Describes the fragment-state associated with a NodeId.
389 /// Currently only unfragmented paths have entries in the table,
390 /// but longer-term this enum is expected to expand to also
391 /// include data for fragmented paths.
392 #[derive(Copy, Clone, Debug)]
393 pub enum FragmentInfo {
394 Moved { var: NodeId, move_expr: NodeId },
395 Assigned { var: NodeId, assign_expr: NodeId, assignee_id: NodeId },
398 // Flags that we track on types. These flags are propagated upwards
399 // through the type during type construction, so that we can quickly
400 // check whether the type has various kinds of types in it without
401 // recursing over the type itself.
403 flags TypeFlags: u32 {
404 const HAS_PARAMS = 1 << 0,
405 const HAS_SELF = 1 << 1,
406 const HAS_TY_INFER = 1 << 2,
407 const HAS_RE_INFER = 1 << 3,
408 const HAS_RE_SKOL = 1 << 4,
409 const HAS_RE_EARLY_BOUND = 1 << 5,
410 const HAS_FREE_REGIONS = 1 << 6,
411 const HAS_TY_ERR = 1 << 7,
412 const HAS_PROJECTION = 1 << 8,
413 const HAS_TY_CLOSURE = 1 << 9,
415 // true if there are "names" of types and regions and so forth
416 // that are local to a particular fn
417 const HAS_LOCAL_NAMES = 1 << 10,
419 // Present if the type belongs in a local type context.
420 // Only set for TyInfer other than Fresh.
421 const KEEP_IN_LOCAL_TCX = 1 << 11,
423 // Is there a projection that does not involve a bound region?
424 // Currently we can't normalize projections w/ bound regions.
425 const HAS_NORMALIZABLE_PROJECTION = 1 << 12,
427 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
428 TypeFlags::HAS_SELF.bits |
429 TypeFlags::HAS_RE_EARLY_BOUND.bits,
431 // Flags representing the nominal content of a type,
432 // computed by FlagsComputation. If you add a new nominal
433 // flag, it should be added here too.
434 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
435 TypeFlags::HAS_SELF.bits |
436 TypeFlags::HAS_TY_INFER.bits |
437 TypeFlags::HAS_RE_INFER.bits |
438 TypeFlags::HAS_RE_SKOL.bits |
439 TypeFlags::HAS_RE_EARLY_BOUND.bits |
440 TypeFlags::HAS_FREE_REGIONS.bits |
441 TypeFlags::HAS_TY_ERR.bits |
442 TypeFlags::HAS_PROJECTION.bits |
443 TypeFlags::HAS_TY_CLOSURE.bits |
444 TypeFlags::HAS_LOCAL_NAMES.bits |
445 TypeFlags::KEEP_IN_LOCAL_TCX.bits,
447 // Caches for type_is_sized, type_moves_by_default
448 const SIZEDNESS_CACHED = 1 << 16,
449 const IS_SIZED = 1 << 17,
450 const MOVENESS_CACHED = 1 << 18,
451 const MOVES_BY_DEFAULT = 1 << 19,
452 const FREEZENESS_CACHED = 1 << 20,
453 const IS_FREEZE = 1 << 21,
454 const NEEDS_DROP_CACHED = 1 << 22,
455 const NEEDS_DROP = 1 << 23,
459 pub struct TyS<'tcx> {
460 pub sty: TypeVariants<'tcx>,
461 pub flags: Cell<TypeFlags>,
463 // the maximal depth of any bound regions appearing in this type.
467 impl<'tcx> PartialEq for TyS<'tcx> {
469 fn eq(&self, other: &TyS<'tcx>) -> bool {
470 // (self as *const _) == (other as *const _)
471 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
474 impl<'tcx> Eq for TyS<'tcx> {}
476 impl<'tcx> Hash for TyS<'tcx> {
477 fn hash<H: Hasher>(&self, s: &mut H) {
478 (self as *const TyS).hash(s)
482 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for ty::TyS<'tcx> {
483 fn hash_stable<W: StableHasherResult>(&self,
484 hcx: &mut StableHashingContext<'a, 'tcx>,
485 hasher: &mut StableHasher<W>) {
489 // The other fields just provide fast access to information that is
490 // also contained in `sty`, so no need to hash them.
495 sty.hash_stable(hcx, hasher);
499 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
501 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
502 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
504 /// A wrapper for slices with the additional invariant
505 /// that the slice is interned and no other slice with
506 /// the same contents can exist in the same context.
507 /// This means we can use pointer + length for both
508 /// equality comparisons and hashing.
509 #[derive(Debug, RustcEncodable)]
510 pub struct Slice<T>([T]);
512 impl<T> PartialEq for Slice<T> {
514 fn eq(&self, other: &Slice<T>) -> bool {
515 (&self.0 as *const [T]) == (&other.0 as *const [T])
518 impl<T> Eq for Slice<T> {}
520 impl<T> Hash for Slice<T> {
521 fn hash<H: Hasher>(&self, s: &mut H) {
522 (self.as_ptr(), self.len()).hash(s)
526 impl<T> Deref for Slice<T> {
528 fn deref(&self) -> &[T] {
533 impl<'a, T> IntoIterator for &'a Slice<T> {
535 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
536 fn into_iter(self) -> Self::IntoIter {
541 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {}
544 pub fn empty<'a>() -> &'a Slice<T> {
546 mem::transmute(slice::from_raw_parts(0x1 as *const T, 0))
551 /// Upvars do not get their own node-id. Instead, we use the pair of
552 /// the original var id (that is, the root variable that is referenced
553 /// by the upvar) and the id of the closure expression.
554 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
557 pub closure_expr_id: NodeId,
560 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
561 pub enum BorrowKind {
562 /// Data must be immutable and is aliasable.
565 /// Data must be immutable but not aliasable. This kind of borrow
566 /// cannot currently be expressed by the user and is used only in
567 /// implicit closure bindings. It is needed when the closure
568 /// is borrowing or mutating a mutable referent, e.g.:
570 /// let x: &mut isize = ...;
571 /// let y = || *x += 5;
573 /// If we were to try to translate this closure into a more explicit
574 /// form, we'd encounter an error with the code as written:
576 /// struct Env { x: & &mut isize }
577 /// let x: &mut isize = ...;
578 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
579 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
581 /// This is then illegal because you cannot mutate a `&mut` found
582 /// in an aliasable location. To solve, you'd have to translate with
583 /// an `&mut` borrow:
585 /// struct Env { x: & &mut isize }
586 /// let x: &mut isize = ...;
587 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
588 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
590 /// Now the assignment to `**env.x` is legal, but creating a
591 /// mutable pointer to `x` is not because `x` is not mutable. We
592 /// could fix this by declaring `x` as `let mut x`. This is ok in
593 /// user code, if awkward, but extra weird for closures, since the
594 /// borrow is hidden.
596 /// So we introduce a "unique imm" borrow -- the referent is
597 /// immutable, but not aliasable. This solves the problem. For
598 /// simplicity, we don't give users the way to express this
599 /// borrow, it's just used when translating closures.
602 /// Data is mutable and not aliasable.
606 /// Information describing the capture of an upvar. This is computed
607 /// during `typeck`, specifically by `regionck`.
608 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
609 pub enum UpvarCapture<'tcx> {
610 /// Upvar is captured by value. This is always true when the
611 /// closure is labeled `move`, but can also be true in other cases
612 /// depending on inference.
615 /// Upvar is captured by reference.
616 ByRef(UpvarBorrow<'tcx>),
619 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
620 pub struct UpvarBorrow<'tcx> {
621 /// The kind of borrow: by-ref upvars have access to shared
622 /// immutable borrows, which are not part of the normal language
624 pub kind: BorrowKind,
626 /// Region of the resulting reference.
627 pub region: ty::Region<'tcx>,
630 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
632 #[derive(Copy, Clone)]
633 pub struct ClosureUpvar<'tcx> {
639 #[derive(Clone, Copy, PartialEq)]
640 pub enum IntVarValue {
642 UintType(ast::UintTy),
645 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
646 pub struct TypeParameterDef {
650 pub has_default: bool,
651 pub object_lifetime_default: ObjectLifetimeDefault,
653 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
654 /// on generic parameter `T`, asserts data behind the parameter
655 /// `T` won't be accessed during the parent type's `Drop` impl.
656 pub pure_wrt_drop: bool,
659 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
660 pub struct RegionParameterDef {
664 pub issue_32330: Option<ty::Issue32330>,
666 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
667 /// on generic parameter `'a`, asserts data of lifetime `'a`
668 /// won't be accessed during the parent type's `Drop` impl.
669 pub pure_wrt_drop: bool,
672 impl RegionParameterDef {
673 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
674 ty::EarlyBoundRegion {
680 pub fn to_bound_region(&self) -> ty::BoundRegion {
681 ty::BoundRegion::BrNamed(self.def_id, self.name)
685 /// Information about the formal type/lifetime parameters associated
686 /// with an item or method. Analogous to hir::Generics.
687 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
688 pub struct Generics {
689 pub parent: Option<DefId>,
690 pub parent_regions: u32,
691 pub parent_types: u32,
692 pub regions: Vec<RegionParameterDef>,
693 pub types: Vec<TypeParameterDef>,
695 /// Reverse map to each `TypeParameterDef`'s `index` field, from
696 /// `def_id.index` (`def_id.krate` is the same as the item's).
697 pub type_param_to_index: BTreeMap<DefIndex, u32>,
703 pub fn parent_count(&self) -> usize {
704 self.parent_regions as usize + self.parent_types as usize
707 pub fn own_count(&self) -> usize {
708 self.regions.len() + self.types.len()
711 pub fn count(&self) -> usize {
712 self.parent_count() + self.own_count()
715 pub fn region_param(&self, param: &EarlyBoundRegion) -> &RegionParameterDef {
716 assert_eq!(self.parent_count(), 0);
717 &self.regions[param.index as usize - self.has_self as usize]
720 pub fn type_param(&self, param: &ParamTy) -> &TypeParameterDef {
721 assert_eq!(self.parent_count(), 0);
722 &self.types[param.idx as usize - self.has_self as usize - self.regions.len()]
726 /// Bounds on generics.
727 #[derive(Clone, Default)]
728 pub struct GenericPredicates<'tcx> {
729 pub parent: Option<DefId>,
730 pub predicates: Vec<Predicate<'tcx>>,
733 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
734 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
736 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
737 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
738 -> InstantiatedPredicates<'tcx> {
739 let mut instantiated = InstantiatedPredicates::empty();
740 self.instantiate_into(tcx, &mut instantiated, substs);
743 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
744 -> InstantiatedPredicates<'tcx> {
745 InstantiatedPredicates {
746 predicates: self.predicates.subst(tcx, substs)
750 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
751 instantiated: &mut InstantiatedPredicates<'tcx>,
752 substs: &Substs<'tcx>) {
753 if let Some(def_id) = self.parent {
754 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
756 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
759 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
760 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
761 -> InstantiatedPredicates<'tcx>
763 assert_eq!(self.parent, None);
764 InstantiatedPredicates {
765 predicates: self.predicates.iter().map(|pred| {
766 pred.subst_supertrait(tcx, poly_trait_ref)
772 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
773 pub enum Predicate<'tcx> {
774 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
775 /// the `Self` type of the trait reference and `A`, `B`, and `C`
776 /// would be the type parameters.
777 Trait(PolyTraitPredicate<'tcx>),
779 /// where `T1 == T2`.
780 Equate(PolyEquatePredicate<'tcx>),
783 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
786 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
788 /// where <T as TraitRef>::Name == X, approximately.
789 /// See `ProjectionPredicate` struct for details.
790 Projection(PolyProjectionPredicate<'tcx>),
793 WellFormed(Ty<'tcx>),
795 /// trait must be object-safe
798 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
799 /// for some substitutions `...` and T being a closure type.
800 /// Satisfied (or refuted) once we know the closure's kind.
801 ClosureKind(DefId, ClosureKind),
804 Subtype(PolySubtypePredicate<'tcx>),
807 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
808 /// Performs a substitution suitable for going from a
809 /// poly-trait-ref to supertraits that must hold if that
810 /// poly-trait-ref holds. This is slightly different from a normal
811 /// substitution in terms of what happens with bound regions. See
812 /// lengthy comment below for details.
813 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
814 trait_ref: &ty::PolyTraitRef<'tcx>)
815 -> ty::Predicate<'tcx>
817 // The interaction between HRTB and supertraits is not entirely
818 // obvious. Let me walk you (and myself) through an example.
820 // Let's start with an easy case. Consider two traits:
822 // trait Foo<'a> : Bar<'a,'a> { }
823 // trait Bar<'b,'c> { }
825 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
826 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
827 // knew that `Foo<'x>` (for any 'x) then we also know that
828 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
829 // normal substitution.
831 // In terms of why this is sound, the idea is that whenever there
832 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
833 // holds. So if there is an impl of `T:Foo<'a>` that applies to
834 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
837 // Another example to be careful of is this:
839 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
840 // trait Bar1<'b,'c> { }
842 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
843 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
844 // reason is similar to the previous example: any impl of
845 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
846 // basically we would want to collapse the bound lifetimes from
847 // the input (`trait_ref`) and the supertraits.
849 // To achieve this in practice is fairly straightforward. Let's
850 // consider the more complicated scenario:
852 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
853 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
854 // where both `'x` and `'b` would have a DB index of 1.
855 // The substitution from the input trait-ref is therefore going to be
856 // `'a => 'x` (where `'x` has a DB index of 1).
857 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
858 // early-bound parameter and `'b' is a late-bound parameter with a
860 // - If we replace `'a` with `'x` from the input, it too will have
861 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
862 // just as we wanted.
864 // There is only one catch. If we just apply the substitution `'a
865 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
866 // adjust the DB index because we substituting into a binder (it
867 // tries to be so smart...) resulting in `for<'x> for<'b>
868 // Bar1<'x,'b>` (we have no syntax for this, so use your
869 // imagination). Basically the 'x will have DB index of 2 and 'b
870 // will have DB index of 1. Not quite what we want. So we apply
871 // the substitution to the *contents* of the trait reference,
872 // rather than the trait reference itself (put another way, the
873 // substitution code expects equal binding levels in the values
874 // from the substitution and the value being substituted into, and
875 // this trick achieves that).
877 let substs = &trait_ref.0.substs;
879 Predicate::Trait(ty::Binder(ref data)) =>
880 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
881 Predicate::Equate(ty::Binder(ref data)) =>
882 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
883 Predicate::Subtype(ty::Binder(ref data)) =>
884 Predicate::Subtype(ty::Binder(data.subst(tcx, substs))),
885 Predicate::RegionOutlives(ty::Binder(ref data)) =>
886 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
887 Predicate::TypeOutlives(ty::Binder(ref data)) =>
888 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
889 Predicate::Projection(ty::Binder(ref data)) =>
890 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
891 Predicate::WellFormed(data) =>
892 Predicate::WellFormed(data.subst(tcx, substs)),
893 Predicate::ObjectSafe(trait_def_id) =>
894 Predicate::ObjectSafe(trait_def_id),
895 Predicate::ClosureKind(closure_def_id, kind) =>
896 Predicate::ClosureKind(closure_def_id, kind),
901 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
902 pub struct TraitPredicate<'tcx> {
903 pub trait_ref: TraitRef<'tcx>
905 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
907 impl<'tcx> TraitPredicate<'tcx> {
908 pub fn def_id(&self) -> DefId {
909 self.trait_ref.def_id
912 /// Creates the dep-node for selecting/evaluating this trait reference.
913 fn dep_node(&self) -> DepNode<DefId> {
914 // Extact the trait-def and first def-id from inputs. See the
915 // docs for `DepNode::TraitSelect` for more information.
916 let trait_def_id = self.def_id();
919 .flat_map(|t| t.walk())
920 .filter_map(|t| match t.sty {
921 ty::TyAdt(adt_def, _) => Some(adt_def.did),
925 .unwrap_or(trait_def_id);
926 DepNode::TraitSelect {
927 trait_def_id: trait_def_id,
928 input_def_id: input_def_id
932 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
933 self.trait_ref.input_types()
936 pub fn self_ty(&self) -> Ty<'tcx> {
937 self.trait_ref.self_ty()
941 impl<'tcx> PolyTraitPredicate<'tcx> {
942 pub fn def_id(&self) -> DefId {
943 // ok to skip binder since trait def-id does not care about regions
947 pub fn dep_node(&self) -> DepNode<DefId> {
948 // ok to skip binder since depnode does not care about regions
953 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
954 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
955 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
957 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
958 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
959 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
960 pub type PolyRegionOutlivesPredicate<'tcx> = PolyOutlivesPredicate<ty::Region<'tcx>,
962 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
964 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
965 pub struct SubtypePredicate<'tcx> {
966 pub a_is_expected: bool,
970 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
972 /// This kind of predicate has no *direct* correspondent in the
973 /// syntax, but it roughly corresponds to the syntactic forms:
975 /// 1. `T : TraitRef<..., Item=Type>`
976 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
978 /// In particular, form #1 is "desugared" to the combination of a
979 /// normal trait predicate (`T : TraitRef<...>`) and one of these
980 /// predicates. Form #2 is a broader form in that it also permits
981 /// equality between arbitrary types. Processing an instance of Form
982 /// #2 eventually yields one of these `ProjectionPredicate`
983 /// instances to normalize the LHS.
984 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
985 pub struct ProjectionPredicate<'tcx> {
986 pub projection_ty: ProjectionTy<'tcx>,
990 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
992 impl<'tcx> PolyProjectionPredicate<'tcx> {
993 pub fn item_name(&self) -> Name {
994 self.0.projection_ty.item_name // safe to skip the binder to access a name
998 pub trait ToPolyTraitRef<'tcx> {
999 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1002 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1003 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1004 assert!(!self.has_escaping_regions());
1005 ty::Binder(self.clone())
1009 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1010 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1011 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1015 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
1016 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1017 // Note: unlike with TraitRef::to_poly_trait_ref(),
1018 // self.0.trait_ref is permitted to have escaping regions.
1019 // This is because here `self` has a `Binder` and so does our
1020 // return value, so we are preserving the number of binding
1022 ty::Binder(self.0.projection_ty.trait_ref)
1026 pub trait ToPredicate<'tcx> {
1027 fn to_predicate(&self) -> Predicate<'tcx>;
1030 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1031 fn to_predicate(&self) -> Predicate<'tcx> {
1032 // we're about to add a binder, so let's check that we don't
1033 // accidentally capture anything, or else that might be some
1034 // weird debruijn accounting.
1035 assert!(!self.has_escaping_regions());
1037 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
1038 trait_ref: self.clone()
1043 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1044 fn to_predicate(&self) -> Predicate<'tcx> {
1045 ty::Predicate::Trait(self.to_poly_trait_predicate())
1049 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
1050 fn to_predicate(&self) -> Predicate<'tcx> {
1051 Predicate::Equate(self.clone())
1055 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1056 fn to_predicate(&self) -> Predicate<'tcx> {
1057 Predicate::RegionOutlives(self.clone())
1061 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1062 fn to_predicate(&self) -> Predicate<'tcx> {
1063 Predicate::TypeOutlives(self.clone())
1067 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1068 fn to_predicate(&self) -> Predicate<'tcx> {
1069 Predicate::Projection(self.clone())
1073 impl<'tcx> Predicate<'tcx> {
1074 /// Iterates over the types in this predicate. Note that in all
1075 /// cases this is skipping over a binder, so late-bound regions
1076 /// with depth 0 are bound by the predicate.
1077 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1078 let vec: Vec<_> = match *self {
1079 ty::Predicate::Trait(ref data) => {
1080 data.skip_binder().input_types().collect()
1082 ty::Predicate::Equate(ty::Binder(ref data)) => {
1083 vec![data.0, data.1]
1085 ty::Predicate::Subtype(ty::Binder(SubtypePredicate { a, b, a_is_expected: _ })) => {
1088 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
1091 ty::Predicate::RegionOutlives(..) => {
1094 ty::Predicate::Projection(ref data) => {
1095 let trait_inputs = data.0.projection_ty.trait_ref.input_types();
1096 trait_inputs.chain(Some(data.0.ty)).collect()
1098 ty::Predicate::WellFormed(data) => {
1101 ty::Predicate::ObjectSafe(_trait_def_id) => {
1104 ty::Predicate::ClosureKind(_closure_def_id, _kind) => {
1109 // The only reason to collect into a vector here is that I was
1110 // too lazy to make the full (somewhat complicated) iterator
1111 // type that would be needed here. But I wanted this fn to
1112 // return an iterator conceptually, rather than a `Vec`, so as
1113 // to be closer to `Ty::walk`.
1117 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1119 Predicate::Trait(ref t) => {
1120 Some(t.to_poly_trait_ref())
1122 Predicate::Projection(..) |
1123 Predicate::Equate(..) |
1124 Predicate::Subtype(..) |
1125 Predicate::RegionOutlives(..) |
1126 Predicate::WellFormed(..) |
1127 Predicate::ObjectSafe(..) |
1128 Predicate::ClosureKind(..) |
1129 Predicate::TypeOutlives(..) => {
1136 /// Represents the bounds declared on a particular set of type
1137 /// parameters. Should eventually be generalized into a flag list of
1138 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1139 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1140 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1141 /// the `GenericPredicates` are expressed in terms of the bound type
1142 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1143 /// represented a set of bounds for some particular instantiation,
1144 /// meaning that the generic parameters have been substituted with
1149 /// struct Foo<T,U:Bar<T>> { ... }
1151 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1152 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1153 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1154 /// [usize:Bar<isize>]]`.
1156 pub struct InstantiatedPredicates<'tcx> {
1157 pub predicates: Vec<Predicate<'tcx>>,
1160 impl<'tcx> InstantiatedPredicates<'tcx> {
1161 pub fn empty() -> InstantiatedPredicates<'tcx> {
1162 InstantiatedPredicates { predicates: vec![] }
1165 pub fn is_empty(&self) -> bool {
1166 self.predicates.is_empty()
1170 /// When type checking, we use the `ParameterEnvironment` to track
1171 /// details about the type/lifetime parameters that are in scope.
1172 /// It primarily stores the bounds information.
1174 /// Note: This information might seem to be redundant with the data in
1175 /// `tcx.ty_param_defs`, but it is not. That table contains the
1176 /// parameter definitions from an "outside" perspective, but this
1177 /// struct will contain the bounds for a parameter as seen from inside
1178 /// the function body. Currently the only real distinction is that
1179 /// bound lifetime parameters are replaced with free ones, but in the
1180 /// future I hope to refine the representation of types so as to make
1181 /// more distinctions clearer.
1183 pub struct ParameterEnvironment<'tcx> {
1184 /// See `construct_free_substs` for details.
1185 pub free_substs: &'tcx Substs<'tcx>,
1187 /// Each type parameter has an implicit region bound that
1188 /// indicates it must outlive at least the function body (the user
1189 /// may specify stronger requirements). This field indicates the
1190 /// region of the callee. If it is `None`, then the parameter
1191 /// environment is for an item or something where the "callee" is
1193 pub implicit_region_bound: Option<ty::Region<'tcx>>,
1195 /// Obligations that the caller must satisfy. This is basically
1196 /// the set of bounds on the in-scope type parameters, translated
1197 /// into Obligations, and elaborated and normalized.
1198 pub caller_bounds: &'tcx [ty::Predicate<'tcx>],
1200 /// Scope that is attached to free regions for this scope. This is
1201 /// usually the id of the fn body, but for more abstract scopes
1202 /// like structs we use None or the item extent.
1204 /// FIXME(#3696). It would be nice to refactor so that free
1205 /// regions don't have this implicit scope and instead introduce
1206 /// relationships in the environment.
1207 pub free_id_outlive: Option<CodeExtent<'tcx>>,
1209 /// A cache for `moves_by_default`.
1210 pub is_copy_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1212 /// A cache for `type_is_sized`
1213 pub is_sized_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1215 /// A cache for `type_is_freeze`
1216 pub is_freeze_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1219 impl<'a, 'tcx> ParameterEnvironment<'tcx> {
1220 pub fn with_caller_bounds(&self,
1221 caller_bounds: &'tcx [ty::Predicate<'tcx>])
1222 -> ParameterEnvironment<'tcx>
1224 ParameterEnvironment {
1225 free_substs: self.free_substs,
1226 implicit_region_bound: self.implicit_region_bound,
1227 caller_bounds: caller_bounds,
1228 free_id_outlive: self.free_id_outlive,
1229 is_copy_cache: RefCell::new(FxHashMap()),
1230 is_sized_cache: RefCell::new(FxHashMap()),
1231 is_freeze_cache: RefCell::new(FxHashMap()),
1235 /// Construct a parameter environment given an item, impl item, or trait item
1236 pub fn for_item(tcx: TyCtxt<'a, 'tcx, 'tcx>, id: NodeId)
1237 -> ParameterEnvironment<'tcx> {
1238 match tcx.hir.find(id) {
1239 Some(hir_map::NodeImplItem(ref impl_item)) => {
1240 match impl_item.node {
1241 hir::ImplItemKind::Type(_) | hir::ImplItemKind::Const(..) => {
1242 // associated types don't have their own entry (for some reason),
1243 // so for now just grab environment for the impl
1244 let impl_id = tcx.hir.get_parent(id);
1245 let impl_def_id = tcx.hir.local_def_id(impl_id);
1246 tcx.construct_parameter_environment(impl_item.span,
1248 Some(tcx.item_extent(id)))
1250 hir::ImplItemKind::Method(_, ref body) => {
1251 tcx.construct_parameter_environment(
1253 tcx.hir.local_def_id(id),
1254 Some(tcx.call_site_extent(id, body.node_id)))
1258 Some(hir_map::NodeTraitItem(trait_item)) => {
1259 match trait_item.node {
1260 hir::TraitItemKind::Type(..) | hir::TraitItemKind::Const(..) => {
1261 // associated types don't have their own entry (for some reason),
1262 // so for now just grab environment for the trait
1263 let trait_id = tcx.hir.get_parent(id);
1264 let trait_def_id = tcx.hir.local_def_id(trait_id);
1265 tcx.construct_parameter_environment(trait_item.span,
1267 Some(tcx.item_extent(id)))
1269 hir::TraitItemKind::Method(_, ref body) => {
1270 // Use call-site for extent (unless this is a
1271 // trait method with no default; then fallback
1272 // to the method id).
1273 let extent = if let hir::TraitMethod::Provided(body_id) = *body {
1274 // default impl: use call_site extent as free_id_outlive bound.
1275 tcx.call_site_extent(id, body_id.node_id)
1277 // no default impl: use item extent as free_id_outlive bound.
1280 tcx.construct_parameter_environment(
1282 tcx.hir.local_def_id(id),
1287 Some(hir_map::NodeItem(item)) => {
1289 hir::ItemFn(.., body_id) => {
1290 // We assume this is a function.
1291 let fn_def_id = tcx.hir.local_def_id(id);
1293 tcx.construct_parameter_environment(
1296 Some(tcx.call_site_extent(id, body_id.node_id)))
1299 hir::ItemStruct(..) |
1300 hir::ItemUnion(..) |
1303 hir::ItemConst(..) |
1304 hir::ItemStatic(..) => {
1305 let def_id = tcx.hir.local_def_id(id);
1306 tcx.construct_parameter_environment(item.span,
1308 Some(tcx.item_extent(id)))
1310 hir::ItemTrait(..) => {
1311 let def_id = tcx.hir.local_def_id(id);
1312 tcx.construct_parameter_environment(item.span,
1314 Some(tcx.item_extent(id)))
1317 span_bug!(item.span,
1318 "ParameterEnvironment::for_item():
1319 can't create a parameter \
1320 environment for this kind of item")
1324 Some(hir_map::NodeExpr(expr)) => {
1325 // This is a convenience to allow closures to work.
1326 if let hir::ExprClosure(.., body, _) = expr.node {
1327 let def_id = tcx.hir.local_def_id(id);
1328 let base_def_id = tcx.closure_base_def_id(def_id);
1329 tcx.construct_parameter_environment(
1332 Some(tcx.call_site_extent(id, body.node_id)))
1334 tcx.empty_parameter_environment()
1337 Some(hir_map::NodeForeignItem(item)) => {
1338 let def_id = tcx.hir.local_def_id(id);
1339 tcx.construct_parameter_environment(item.span,
1343 Some(hir_map::NodeStructCtor(..)) |
1344 Some(hir_map::NodeVariant(..)) => {
1345 let def_id = tcx.hir.local_def_id(id);
1346 tcx.construct_parameter_environment(tcx.hir.span(id),
1351 bug!("ParameterEnvironment::from_item(): \
1352 `{}` = {:?} is unsupported",
1353 tcx.hir.node_to_string(id), it)
1359 #[derive(Copy, Clone, Debug)]
1360 pub struct Destructor {
1361 /// The def-id of the destructor method
1366 flags AdtFlags: u32 {
1367 const NO_ADT_FLAGS = 0,
1368 const IS_ENUM = 1 << 0,
1369 const IS_PHANTOM_DATA = 1 << 1,
1370 const IS_FUNDAMENTAL = 1 << 2,
1371 const IS_UNION = 1 << 3,
1372 const IS_BOX = 1 << 4,
1377 pub struct VariantDef {
1378 /// The variant's DefId. If this is a tuple-like struct,
1379 /// this is the DefId of the struct's ctor.
1381 pub name: Name, // struct's name if this is a struct
1382 pub discr: VariantDiscr,
1383 pub fields: Vec<FieldDef>,
1384 pub ctor_kind: CtorKind,
1387 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1388 pub enum VariantDiscr {
1389 /// Explicit value for this variant, i.e. `X = 123`.
1390 /// The `DefId` corresponds to the embedded constant.
1393 /// The previous variant's discriminant plus one.
1394 /// For efficiency reasons, the distance from the
1395 /// last `Explicit` discriminant is being stored,
1396 /// or `0` for the first variant, if it has none.
1401 pub struct FieldDef {
1404 pub vis: Visibility,
1407 /// The definition of an abstract data type - a struct or enum.
1409 /// These are all interned (by intern_adt_def) into the adt_defs
1413 pub variants: Vec<VariantDef>,
1415 pub repr: ReprOptions,
1418 impl PartialEq for AdtDef {
1419 // AdtDef are always interned and this is part of TyS equality
1421 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1424 impl Eq for AdtDef {}
1426 impl Hash for AdtDef {
1428 fn hash<H: Hasher>(&self, s: &mut H) {
1429 (self as *const AdtDef).hash(s)
1433 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1434 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1439 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1442 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for AdtDef {
1443 fn hash_stable<W: StableHasherResult>(&self,
1444 hcx: &mut StableHashingContext<'a, 'tcx>,
1445 hasher: &mut StableHasher<W>) {
1453 did.hash_stable(hcx, hasher);
1454 variants.hash_stable(hcx, hasher);
1455 flags.hash_stable(hcx, hasher);
1456 repr.hash_stable(hcx, hasher);
1460 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1461 pub enum AdtKind { Struct, Union, Enum }
1464 #[derive(RustcEncodable, RustcDecodable, Default)]
1465 flags ReprFlags: u8 {
1466 const IS_C = 1 << 0,
1467 const IS_PACKED = 1 << 1,
1468 const IS_SIMD = 1 << 2,
1469 // Internal only for now. If true, don't reorder fields.
1470 const IS_LINEAR = 1 << 3,
1472 // Any of these flags being set prevent field reordering optimisation.
1473 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1474 ReprFlags::IS_PACKED.bits |
1475 ReprFlags::IS_SIMD.bits |
1476 ReprFlags::IS_LINEAR.bits,
1480 impl_stable_hash_for!(struct ReprFlags {
1486 /// Represents the repr options provided by the user,
1487 #[derive(Copy, Clone, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1488 pub struct ReprOptions {
1489 pub int: Option<attr::IntType>,
1491 pub flags: ReprFlags,
1494 impl_stable_hash_for!(struct ReprOptions {
1501 pub fn new(tcx: TyCtxt, did: DefId) -> ReprOptions {
1502 let mut flags = ReprFlags::empty();
1503 let mut size = None;
1504 let mut max_align = 0;
1505 for attr in tcx.get_attrs(did).iter() {
1506 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1507 flags.insert(match r {
1508 attr::ReprExtern => ReprFlags::IS_C,
1509 attr::ReprPacked => ReprFlags::IS_PACKED,
1510 attr::ReprSimd => ReprFlags::IS_SIMD,
1511 attr::ReprInt(i) => {
1515 attr::ReprAlign(align) => {
1516 max_align = cmp::max(align, max_align);
1523 // FIXME(eddyb) This is deprecated and should be removed.
1524 if tcx.has_attr(did, "simd") {
1525 flags.insert(ReprFlags::IS_SIMD);
1528 // This is here instead of layout because the choice must make it into metadata.
1529 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1530 flags.insert(ReprFlags::IS_LINEAR);
1532 ReprOptions { int: size, align: max_align, flags: flags }
1536 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1538 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1540 pub fn packed(&self) -> bool { self.flags.contains(ReprFlags::IS_PACKED) }
1542 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1544 pub fn discr_type(&self) -> attr::IntType {
1545 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Is))
1548 /// Returns true if this `#[repr()]` should inhabit "smart enum
1549 /// layout" optimizations, such as representing `Foo<&T>` as a
1551 pub fn inhibit_enum_layout_opt(&self) -> bool {
1552 self.c() || self.int.is_some()
1556 impl<'a, 'gcx, 'tcx> AdtDef {
1560 variants: Vec<VariantDef>,
1561 repr: ReprOptions) -> Self {
1562 let mut flags = AdtFlags::NO_ADT_FLAGS;
1563 let attrs = tcx.get_attrs(did);
1564 if attr::contains_name(&attrs, "fundamental") {
1565 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1567 if Some(did) == tcx.lang_items.phantom_data() {
1568 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1570 if Some(did) == tcx.lang_items.owned_box() {
1571 flags = flags | AdtFlags::IS_BOX;
1574 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
1575 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
1576 AdtKind::Struct => {}
1587 pub fn is_struct(&self) -> bool {
1588 !self.is_union() && !self.is_enum()
1592 pub fn is_union(&self) -> bool {
1593 self.flags.intersects(AdtFlags::IS_UNION)
1597 pub fn is_enum(&self) -> bool {
1598 self.flags.intersects(AdtFlags::IS_ENUM)
1601 /// Returns the kind of the ADT - Struct or Enum.
1603 pub fn adt_kind(&self) -> AdtKind {
1606 } else if self.is_union() {
1613 pub fn descr(&self) -> &'static str {
1614 match self.adt_kind() {
1615 AdtKind::Struct => "struct",
1616 AdtKind::Union => "union",
1617 AdtKind::Enum => "enum",
1621 pub fn variant_descr(&self) -> &'static str {
1622 match self.adt_kind() {
1623 AdtKind::Struct => "struct",
1624 AdtKind::Union => "union",
1625 AdtKind::Enum => "variant",
1629 /// Returns whether this type is #[fundamental] for the purposes
1630 /// of coherence checking.
1632 pub fn is_fundamental(&self) -> bool {
1633 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
1636 /// Returns true if this is PhantomData<T>.
1638 pub fn is_phantom_data(&self) -> bool {
1639 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
1642 /// Returns true if this is Box<T>.
1644 pub fn is_box(&self) -> bool {
1645 self.flags.intersects(AdtFlags::IS_BOX)
1648 /// Returns whether this type has a destructor.
1649 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
1650 self.destructor(tcx).is_some()
1653 /// Asserts this is a struct and returns the struct's unique
1655 pub fn struct_variant(&self) -> &VariantDef {
1656 assert!(!self.is_enum());
1661 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
1662 tcx.predicates_of(self.did)
1665 /// Returns an iterator over all fields contained
1668 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
1669 self.variants.iter().flat_map(|v| v.fields.iter())
1673 pub fn is_univariant(&self) -> bool {
1674 self.variants.len() == 1
1677 pub fn is_payloadfree(&self) -> bool {
1678 !self.variants.is_empty() &&
1679 self.variants.iter().all(|v| v.fields.is_empty())
1682 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
1685 .find(|v| v.did == vid)
1686 .expect("variant_with_id: unknown variant")
1689 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1692 .position(|v| v.did == vid)
1693 .expect("variant_index_with_id: unknown variant")
1696 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
1698 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
1699 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
1700 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.struct_variant(),
1701 _ => bug!("unexpected def {:?} in variant_of_def", def)
1706 pub fn discriminants(&'a self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1707 -> impl Iterator<Item=ConstInt> + 'a {
1708 let repr_type = self.repr.discr_type();
1709 let initial = repr_type.initial_discriminant(tcx.global_tcx());
1710 let mut prev_discr = None::<ConstInt>;
1711 self.variants.iter().map(move |v| {
1712 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr());
1713 if let VariantDiscr::Explicit(expr_did) = v.discr {
1714 let substs = Substs::empty();
1715 match tcx.const_eval((expr_did, substs)) {
1716 Ok(ConstVal::Integral(v)) => {
1720 if !expr_did.is_local() {
1721 span_bug!(tcx.def_span(expr_did),
1722 "variant discriminant evaluation succeeded \
1723 in its crate but failed locally: {:?}", err);
1728 prev_discr = Some(discr);
1734 /// Compute the discriminant value used by a specific variant.
1735 /// Unlike `discriminants`, this is (amortized) constant-time,
1736 /// only doing at most one query for evaluating an explicit
1737 /// discriminant (the last one before the requested variant),
1738 /// assuming there are no constant-evaluation errors there.
1739 pub fn discriminant_for_variant(&self,
1740 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1741 variant_index: usize)
1743 let repr_type = self.repr.discr_type();
1744 let mut explicit_value = repr_type.initial_discriminant(tcx.global_tcx());
1745 let mut explicit_index = variant_index;
1747 match self.variants[explicit_index].discr {
1748 ty::VariantDiscr::Relative(0) => break,
1749 ty::VariantDiscr::Relative(distance) => {
1750 explicit_index -= distance;
1752 ty::VariantDiscr::Explicit(expr_did) => {
1753 let substs = Substs::empty();
1754 match tcx.const_eval((expr_did, substs)) {
1755 Ok(ConstVal::Integral(v)) => {
1760 if !expr_did.is_local() {
1761 span_bug!(tcx.def_span(expr_did),
1762 "variant discriminant evaluation succeeded \
1763 in its crate but failed locally: {:?}", err);
1765 if explicit_index == 0 {
1768 explicit_index -= 1;
1774 let discr = explicit_value.to_u128_unchecked()
1775 .wrapping_add((variant_index - explicit_index) as u128);
1777 attr::UnsignedInt(ty) => {
1778 ConstInt::new_unsigned_truncating(discr, ty,
1779 tcx.sess.target.uint_type)
1781 attr::SignedInt(ty) => {
1782 ConstInt::new_signed_truncating(discr as i128, ty,
1783 tcx.sess.target.int_type)
1788 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
1789 tcx.adt_destructor(self.did)
1792 /// Returns a list of types such that `Self: Sized` if and only
1793 /// if that type is Sized, or `TyErr` if this type is recursive.
1795 /// Oddly enough, checking that the sized-constraint is Sized is
1796 /// actually more expressive than checking all members:
1797 /// the Sized trait is inductive, so an associated type that references
1798 /// Self would prevent its containing ADT from being Sized.
1800 /// Due to normalization being eager, this applies even if
1801 /// the associated type is behind a pointer, e.g. issue #31299.
1802 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
1803 match queries::adt_sized_constraint::try_get(tcx, DUMMY_SP, self.did) {
1806 debug!("adt_sized_constraint: {:?} is recursive", self);
1807 // This should be reported as an error by `check_representable`.
1809 // Consider the type as Sized in the meanwhile to avoid
1811 tcx.intern_type_list(&[tcx.types.err])
1816 fn sized_constraint_for_ty(&self,
1817 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1820 let result = match ty.sty {
1821 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
1822 TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
1823 TyArray(..) | TyClosure(..) | TyNever => {
1827 TyStr | TyDynamic(..) | TySlice(_) | TyError => {
1828 // these are never sized - return the target type
1832 TyTuple(ref tys, _) => {
1835 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
1839 TyAdt(adt, substs) => {
1841 let adt_tys = adt.sized_constraint(tcx);
1842 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
1845 .map(|ty| ty.subst(tcx, substs))
1846 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
1850 TyProjection(..) | TyAnon(..) => {
1851 // must calculate explicitly.
1852 // FIXME: consider special-casing always-Sized projections
1857 // perf hack: if there is a `T: Sized` bound, then
1858 // we know that `T` is Sized and do not need to check
1861 let sized_trait = match tcx.lang_items.sized_trait() {
1863 _ => return vec![ty]
1865 let sized_predicate = Binder(TraitRef {
1866 def_id: sized_trait,
1867 substs: tcx.mk_substs_trait(ty, &[])
1869 let predicates = tcx.predicates_of(self.did).predicates;
1870 if predicates.into_iter().any(|p| p == sized_predicate) {
1878 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
1882 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
1887 impl<'a, 'gcx, 'tcx> VariantDef {
1889 pub fn find_field_named(&self,
1891 -> Option<&FieldDef> {
1892 self.fields.iter().find(|f| f.name == name)
1896 pub fn index_of_field_named(&self,
1899 self.fields.iter().position(|f| f.name == name)
1903 pub fn field_named(&self, name: ast::Name) -> &FieldDef {
1904 self.find_field_named(name).unwrap()
1908 impl<'a, 'gcx, 'tcx> FieldDef {
1909 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1910 tcx.type_of(self.did).subst(tcx, subst)
1914 /// Records the substitutions used to translate the polytype for an
1915 /// item into the monotype of an item reference.
1916 #[derive(Clone, RustcEncodable, RustcDecodable)]
1917 pub struct ItemSubsts<'tcx> {
1918 pub substs: &'tcx Substs<'tcx>,
1921 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1922 pub enum ClosureKind {
1923 // Warning: Ordering is significant here! The ordering is chosen
1924 // because the trait Fn is a subtrait of FnMut and so in turn, and
1925 // hence we order it so that Fn < FnMut < FnOnce.
1931 impl<'a, 'tcx> ClosureKind {
1932 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
1934 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
1935 ClosureKind::FnMut => {
1936 tcx.require_lang_item(FnMutTraitLangItem)
1938 ClosureKind::FnOnce => {
1939 tcx.require_lang_item(FnOnceTraitLangItem)
1944 /// True if this a type that impls this closure kind
1945 /// must also implement `other`.
1946 pub fn extends(self, other: ty::ClosureKind) -> bool {
1947 match (self, other) {
1948 (ClosureKind::Fn, ClosureKind::Fn) => true,
1949 (ClosureKind::Fn, ClosureKind::FnMut) => true,
1950 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
1951 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
1952 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
1953 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
1959 impl<'tcx> TyS<'tcx> {
1960 /// Iterator that walks `self` and any types reachable from
1961 /// `self`, in depth-first order. Note that just walks the types
1962 /// that appear in `self`, it does not descend into the fields of
1963 /// structs or variants. For example:
1966 /// isize => { isize }
1967 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
1968 /// [isize] => { [isize], isize }
1970 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
1971 TypeWalker::new(self)
1974 /// Iterator that walks the immediate children of `self`. Hence
1975 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
1976 /// (but not `i32`, like `walk`).
1977 pub fn walk_shallow(&'tcx self) -> AccIntoIter<walk::TypeWalkerArray<'tcx>> {
1978 walk::walk_shallow(self)
1981 /// Walks `ty` and any types appearing within `ty`, invoking the
1982 /// callback `f` on each type. If the callback returns false, then the
1983 /// children of the current type are ignored.
1985 /// Note: prefer `ty.walk()` where possible.
1986 pub fn maybe_walk<F>(&'tcx self, mut f: F)
1987 where F : FnMut(Ty<'tcx>) -> bool
1989 let mut walker = self.walk();
1990 while let Some(ty) = walker.next() {
1992 walker.skip_current_subtree();
1998 impl<'tcx> ItemSubsts<'tcx> {
1999 pub fn is_noop(&self) -> bool {
2000 self.substs.is_noop()
2004 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
2005 pub enum LvaluePreference {
2010 impl LvaluePreference {
2011 pub fn from_mutbl(m: hir::Mutability) -> Self {
2013 hir::MutMutable => PreferMutLvalue,
2014 hir::MutImmutable => NoPreference,
2020 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2022 hir::MutMutable => MutBorrow,
2023 hir::MutImmutable => ImmBorrow,
2027 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2028 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2029 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2031 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2033 MutBorrow => hir::MutMutable,
2034 ImmBorrow => hir::MutImmutable,
2036 // We have no type corresponding to a unique imm borrow, so
2037 // use `&mut`. It gives all the capabilities of an `&uniq`
2038 // and hence is a safe "over approximation".
2039 UniqueImmBorrow => hir::MutMutable,
2043 pub fn to_user_str(&self) -> &'static str {
2045 MutBorrow => "mutable",
2046 ImmBorrow => "immutable",
2047 UniqueImmBorrow => "uniquely immutable",
2052 #[derive(Debug, Clone)]
2053 pub enum Attributes<'gcx> {
2054 Owned(Rc<[ast::Attribute]>),
2055 Borrowed(&'gcx [ast::Attribute])
2058 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2059 type Target = [ast::Attribute];
2061 fn deref(&self) -> &[ast::Attribute] {
2063 &Attributes::Owned(ref data) => &data,
2064 &Attributes::Borrowed(data) => data
2069 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2070 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2071 self.typeck_tables_of(self.hir.body_owner_def_id(body))
2074 /// Returns an iterator of the def-ids for all body-owners in this
2075 /// crate. If you would prefer to iterate over the bodies
2076 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
2077 pub fn body_owners(self) -> impl Iterator<Item = DefId> + 'a {
2081 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
2084 pub fn expr_span(self, id: NodeId) -> Span {
2085 match self.hir.find(id) {
2086 Some(hir_map::NodeExpr(e)) => {
2090 bug!("Node id {} is not an expr: {:?}", id, f);
2093 bug!("Node id {} is not present in the node map", id);
2098 pub fn local_var_name_str(self, id: NodeId) -> InternedString {
2099 match self.hir.find(id) {
2100 Some(hir_map::NodeLocal(pat)) => {
2102 hir::PatKind::Binding(_, _, ref path1, _) => path1.node.as_str(),
2104 bug!("Variable id {} maps to {:?}, not local", id, pat);
2108 r => bug!("Variable id {} maps to {:?}, not local", id, r),
2112 pub fn expr_is_lval(self, expr: &hir::Expr) -> bool {
2114 hir::ExprPath(hir::QPath::Resolved(_, ref path)) => {
2116 Def::Local(..) | Def::Upvar(..) | Def::Static(..) | Def::Err => true,
2121 hir::ExprType(ref e, _) => {
2122 self.expr_is_lval(e)
2125 hir::ExprUnary(hir::UnDeref, _) |
2126 hir::ExprField(..) |
2127 hir::ExprTupField(..) |
2128 hir::ExprIndex(..) => {
2132 // Partially qualified paths in expressions can only legally
2133 // refer to associated items which are always rvalues.
2134 hir::ExprPath(hir::QPath::TypeRelative(..)) |
2137 hir::ExprMethodCall(..) |
2138 hir::ExprStruct(..) |
2141 hir::ExprMatch(..) |
2142 hir::ExprClosure(..) |
2143 hir::ExprBlock(..) |
2144 hir::ExprRepeat(..) |
2145 hir::ExprArray(..) |
2146 hir::ExprBreak(..) |
2147 hir::ExprAgain(..) |
2149 hir::ExprWhile(..) |
2151 hir::ExprAssign(..) |
2152 hir::ExprInlineAsm(..) |
2153 hir::ExprAssignOp(..) |
2155 hir::ExprUnary(..) |
2157 hir::ExprAddrOf(..) |
2158 hir::ExprBinary(..) |
2159 hir::ExprCast(..) => {
2165 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2166 self.associated_items(id)
2167 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2171 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2172 self.associated_items(did).any(|item| {
2173 item.relevant_for_never()
2177 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2178 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2179 match self.hir.get(node_id) {
2180 hir_map::NodeTraitItem(_) | hir_map::NodeImplItem(_) => true,
2184 match self.describe_def(def_id).expect("no def for def-id") {
2185 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2190 if is_associated_item {
2191 Some(self.associated_item(def_id))
2197 fn associated_item_from_trait_item_ref(self,
2198 parent_def_id: DefId,
2199 parent_vis: &hir::Visibility,
2200 trait_item_ref: &hir::TraitItemRef)
2202 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2203 let (kind, has_self) = match trait_item_ref.kind {
2204 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2205 hir::AssociatedItemKind::Method { has_self } => {
2206 (ty::AssociatedKind::Method, has_self)
2208 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2212 name: trait_item_ref.name,
2214 // Visibility of trait items is inherited from their traits.
2215 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2216 defaultness: trait_item_ref.defaultness,
2218 container: TraitContainer(parent_def_id),
2219 method_has_self_argument: has_self
2223 fn associated_item_from_impl_item_ref(self,
2224 parent_def_id: DefId,
2225 impl_item_ref: &hir::ImplItemRef)
2227 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2228 let (kind, has_self) = match impl_item_ref.kind {
2229 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2230 hir::AssociatedItemKind::Method { has_self } => {
2231 (ty::AssociatedKind::Method, has_self)
2233 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2236 ty::AssociatedItem {
2237 name: impl_item_ref.name,
2239 // Visibility of trait impl items doesn't matter.
2240 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2241 defaultness: impl_item_ref.defaultness,
2243 container: ImplContainer(parent_def_id),
2244 method_has_self_argument: has_self
2248 #[inline] // FIXME(#35870) Avoid closures being unexported due to impl Trait.
2249 pub fn associated_items(self, def_id: DefId)
2250 -> impl Iterator<Item = ty::AssociatedItem> + 'a {
2251 let def_ids = self.associated_item_def_ids(def_id);
2252 (0..def_ids.len()).map(move |i| self.associated_item(def_ids[i]))
2255 /// Returns true if the impls are the same polarity and are implementing
2256 /// a trait which contains no items
2257 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2258 if !self.sess.features.borrow().overlapping_marker_traits {
2261 let trait1_is_empty = self.impl_trait_ref(def_id1)
2262 .map_or(false, |trait_ref| {
2263 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2265 let trait2_is_empty = self.impl_trait_ref(def_id2)
2266 .map_or(false, |trait_ref| {
2267 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2269 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2274 // Returns `ty::VariantDef` if `def` refers to a struct,
2275 // or variant or their constructors, panics otherwise.
2276 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2278 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2279 let enum_did = self.parent_def_id(did).unwrap();
2280 self.adt_def(enum_did).variant_with_id(did)
2282 Def::Struct(did) | Def::Union(did) => {
2283 self.adt_def(did).struct_variant()
2285 Def::StructCtor(ctor_did, ..) => {
2286 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2287 self.adt_def(did).struct_variant()
2289 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2293 pub fn def_key(self, id: DefId) -> hir_map::DefKey {
2295 self.hir.def_key(id)
2297 self.sess.cstore.def_key(id)
2301 /// Convert a `DefId` into its fully expanded `DefPath` (every
2302 /// `DefId` is really just an interned def-path).
2304 /// Note that if `id` is not local to this crate, the result will
2305 /// be a non-local `DefPath`.
2306 pub fn def_path(self, id: DefId) -> hir_map::DefPath {
2308 self.hir.def_path(id)
2310 self.sess.cstore.def_path(id)
2315 pub fn def_path_hash(self, def_id: DefId) -> u64 {
2316 if def_id.is_local() {
2317 self.hir.definitions().def_path_hash(def_id.index)
2319 self.sess.cstore.def_path_hash(def_id)
2323 pub fn vis_is_accessible_from(self, vis: Visibility, block: NodeId) -> bool {
2324 vis.is_accessible_from(self.hir.local_def_id(self.hir.get_module_parent(block)), self)
2327 pub fn item_name(self, id: DefId) -> ast::Name {
2328 if let Some(id) = self.hir.as_local_node_id(id) {
2330 } else if id.index == CRATE_DEF_INDEX {
2331 self.sess.cstore.original_crate_name(id.krate)
2333 let def_key = self.sess.cstore.def_key(id);
2334 // The name of a StructCtor is that of its struct parent.
2335 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2336 self.item_name(DefId {
2338 index: def_key.parent.unwrap()
2341 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2342 bug!("item_name: no name for {:?}", self.def_path(id));
2348 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2349 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2353 ty::InstanceDef::Item(did) => {
2354 self.optimized_mir(did)
2356 ty::InstanceDef::Intrinsic(..) |
2357 ty::InstanceDef::FnPtrShim(..) |
2358 ty::InstanceDef::Virtual(..) |
2359 ty::InstanceDef::ClosureOnceShim { .. } |
2360 ty::InstanceDef::DropGlue(..) => {
2361 self.mir_shims(instance)
2366 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2367 /// Returns None if there is no MIR for the DefId
2368 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2369 if self.is_mir_available(did) {
2370 Some(self.optimized_mir(did))
2376 /// Get the attributes of a definition.
2377 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2378 if let Some(id) = self.hir.as_local_node_id(did) {
2379 Attributes::Borrowed(self.hir.attrs(id))
2381 Attributes::Owned(self.sess.cstore.item_attrs(did))
2385 /// Determine whether an item is annotated with an attribute
2386 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2387 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2390 pub fn trait_has_default_impl(self, trait_def_id: DefId) -> bool {
2391 let def = self.trait_def(trait_def_id);
2392 def.flags.get().intersects(TraitFlags::HAS_DEFAULT_IMPL)
2395 /// Populates the type context with all the implementations for the given
2396 /// trait if necessary.
2397 pub fn populate_implementations_for_trait_if_necessary(self, trait_id: DefId) {
2398 if trait_id.is_local() {
2402 // The type is not local, hence we are reading this out of
2403 // metadata and don't need to track edges.
2404 let _ignore = self.dep_graph.in_ignore();
2406 let def = self.trait_def(trait_id);
2407 if def.flags.get().intersects(TraitFlags::HAS_REMOTE_IMPLS) {
2411 debug!("populate_implementations_for_trait_if_necessary: searching for {:?}", def);
2413 for impl_def_id in self.sess.cstore.implementations_of_trait(Some(trait_id)) {
2414 let trait_ref = self.impl_trait_ref(impl_def_id).unwrap();
2416 // Record the trait->implementation mapping.
2417 let parent = self.sess.cstore.impl_parent(impl_def_id).unwrap_or(trait_id);
2418 def.record_remote_impl(self, impl_def_id, trait_ref, parent);
2421 def.flags.set(def.flags.get() | TraitFlags::HAS_REMOTE_IMPLS);
2424 /// Given the def_id of an impl, return the def_id of the trait it implements.
2425 /// If it implements no trait, return `None`.
2426 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2427 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2430 /// If the given def ID describes a method belonging to an impl, return the
2431 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2432 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2433 let item = if def_id.krate != LOCAL_CRATE {
2434 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2435 Some(self.associated_item(def_id))
2440 self.opt_associated_item(def_id)
2444 Some(trait_item) => {
2445 match trait_item.container {
2446 TraitContainer(_) => None,
2447 ImplContainer(def_id) => Some(def_id),
2454 /// If the given def ID describes an item belonging to a trait,
2455 /// return the ID of the trait that the trait item belongs to.
2456 /// Otherwise, return `None`.
2457 pub fn trait_of_item(self, def_id: DefId) -> Option<DefId> {
2458 if def_id.krate != LOCAL_CRATE {
2459 return self.sess.cstore.trait_of_item(def_id);
2461 self.opt_associated_item(def_id)
2462 .and_then(|associated_item| {
2463 match associated_item.container {
2464 TraitContainer(def_id) => Some(def_id),
2465 ImplContainer(_) => None
2470 /// Construct a parameter environment suitable for static contexts or other contexts where there
2471 /// are no free type/lifetime parameters in scope.
2472 pub fn empty_parameter_environment(self) -> ParameterEnvironment<'tcx> {
2473 ty::ParameterEnvironment {
2474 free_substs: self.intern_substs(&[]),
2475 caller_bounds: Slice::empty(),
2476 implicit_region_bound: None,
2477 free_id_outlive: None,
2478 is_copy_cache: RefCell::new(FxHashMap()),
2479 is_sized_cache: RefCell::new(FxHashMap()),
2480 is_freeze_cache: RefCell::new(FxHashMap()),
2484 /// Constructs and returns a substitution that can be applied to move from
2485 /// the "outer" view of a type or method to the "inner" view.
2486 /// In general, this means converting from bound parameters to
2487 /// free parameters. Since we currently represent bound/free type
2488 /// parameters in the same way, this only has an effect on regions.
2489 pub fn construct_free_substs(self,
2491 free_id_outlive: Option<CodeExtent<'gcx>>)
2492 -> &'gcx Substs<'gcx> {
2494 let substs = Substs::for_item(self.global_tcx(), def_id, |def, _| {
2495 // map bound 'a => free 'a
2496 self.global_tcx().mk_region(ReFree(FreeRegion {
2497 scope: free_id_outlive,
2498 bound_region: def.to_bound_region()
2502 self.global_tcx().mk_param_from_def(def)
2505 debug!("construct_parameter_environment: {:?}", substs);
2509 /// See `ParameterEnvironment` struct def'n for details.
2510 /// If you were using `free_id: NodeId`, you might try `self.region_maps().item_extent(free_id)`
2511 /// for the `free_id_outlive` parameter. (But note that this is not always quite right.)
2512 pub fn construct_parameter_environment(self,
2515 free_id_outlive: Option<CodeExtent<'gcx>>)
2516 -> ParameterEnvironment<'gcx>
2519 // Construct the free substs.
2522 let free_substs = self.construct_free_substs(def_id, free_id_outlive);
2525 // Compute the bounds on Self and the type parameters.
2528 let tcx = self.global_tcx();
2529 let generic_predicates = tcx.predicates_of(def_id);
2530 let bounds = generic_predicates.instantiate(tcx, free_substs);
2531 let bounds = tcx.liberate_late_bound_regions(free_id_outlive, &ty::Binder(bounds));
2532 let predicates = bounds.predicates;
2534 // Finally, we have to normalize the bounds in the environment, in
2535 // case they contain any associated type projections. This process
2536 // can yield errors if the put in illegal associated types, like
2537 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2538 // report these errors right here; this doesn't actually feel
2539 // right to me, because constructing the environment feels like a
2540 // kind of a "idempotent" action, but I'm not sure where would be
2541 // a better place. In practice, we construct environments for
2542 // every fn once during type checking, and we'll abort if there
2543 // are any errors at that point, so after type checking you can be
2544 // sure that this will succeed without errors anyway.
2547 let unnormalized_env = ty::ParameterEnvironment {
2548 free_substs: free_substs,
2549 implicit_region_bound: free_id_outlive.map(|f| tcx.mk_region(ty::ReScope(f))),
2550 caller_bounds: tcx.intern_predicates(&predicates),
2551 free_id_outlive: free_id_outlive,
2552 is_copy_cache: RefCell::new(FxHashMap()),
2553 is_sized_cache: RefCell::new(FxHashMap()),
2554 is_freeze_cache: RefCell::new(FxHashMap()),
2557 let body_id = free_id_outlive.map(|f| f.node_id())
2558 .unwrap_or(DUMMY_NODE_ID);
2559 let cause = traits::ObligationCause::misc(span, body_id);
2560 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
2563 pub fn node_scope_region(self, id: NodeId) -> Region<'tcx> {
2564 self.mk_region(ty::ReScope(self.node_extent(id)))
2567 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2568 /// with the name of the crate containing the impl.
2569 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2570 if impl_did.is_local() {
2571 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2572 Ok(self.hir.span(node_id))
2574 Err(self.sess.cstore.crate_name(impl_did.krate))
2579 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2580 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2581 F: FnOnce(&[hir::Freevar]) -> T,
2583 match self.freevars.borrow().get(&fid) {
2585 Some(d) => f(&d[..])
2590 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
2593 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2594 let parent_id = tcx.hir.get_parent(id);
2595 let parent_def_id = tcx.hir.local_def_id(parent_id);
2596 let parent_item = tcx.hir.expect_item(parent_id);
2597 match parent_item.node {
2598 hir::ItemImpl(.., ref impl_item_refs) => {
2599 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2600 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2602 debug_assert_eq!(assoc_item.def_id, def_id);
2607 hir::ItemTrait(.., ref trait_item_refs) => {
2608 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2609 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2612 debug_assert_eq!(assoc_item.def_id, def_id);
2620 span_bug!(parent_item.span,
2621 "unexpected parent of trait or impl item or item not found: {:?}",
2625 /// Calculates the Sized-constraint.
2627 /// In fact, there are only a few options for the types in the constraint:
2628 /// - an obviously-unsized type
2629 /// - a type parameter or projection whose Sizedness can't be known
2630 /// - a tuple of type parameters or projections, if there are multiple
2632 /// - a TyError, if a type contained itself. The representability
2633 /// check should catch this case.
2634 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2636 -> &'tcx [Ty<'tcx>] {
2637 let def = tcx.adt_def(def_id);
2639 let result = tcx.intern_type_list(&def.variants.iter().flat_map(|v| {
2642 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2643 }).collect::<Vec<_>>());
2645 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2650 /// Calculates the dtorck constraint for a type.
2651 fn adt_dtorck_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2653 -> DtorckConstraint<'tcx> {
2654 let def = tcx.adt_def(def_id);
2655 let span = tcx.def_span(def_id);
2656 debug!("dtorck_constraint: {:?}", def);
2658 if def.is_phantom_data() {
2659 let result = DtorckConstraint {
2662 tcx.mk_param_from_def(&tcx.generics_of(def_id).types[0])
2665 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2669 let mut result = def.all_fields()
2670 .map(|field| tcx.type_of(field.did))
2671 .map(|fty| tcx.dtorck_constraint_for_ty(span, fty, 0, fty))
2672 .collect::<Result<DtorckConstraint, ErrorReported>>()
2673 .unwrap_or(DtorckConstraint::empty());
2674 result.outlives.extend(tcx.destructor_constraints(def));
2677 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2682 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2685 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2686 let item = tcx.hir.expect_item(id);
2687 let vec: Vec<_> = match item.node {
2688 hir::ItemTrait(.., ref trait_item_refs) => {
2689 trait_item_refs.iter()
2690 .map(|trait_item_ref| trait_item_ref.id)
2691 .map(|id| tcx.hir.local_def_id(id.node_id))
2694 hir::ItemImpl(.., ref impl_item_refs) => {
2695 impl_item_refs.iter()
2696 .map(|impl_item_ref| impl_item_ref.id)
2697 .map(|id| tcx.hir.local_def_id(id.node_id))
2700 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2705 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
2706 tcx.hir.span_if_local(def_id).unwrap()
2709 pub fn provide(providers: &mut ty::maps::Providers) {
2710 *providers = ty::maps::Providers {
2712 associated_item_def_ids,
2713 adt_sized_constraint,
2714 adt_dtorck_constraint,
2720 pub fn provide_extern(providers: &mut ty::maps::Providers) {
2721 *providers = ty::maps::Providers {
2722 adt_sized_constraint,
2723 adt_dtorck_constraint,
2729 /// A map for the local crate mapping each type to a vector of its
2730 /// inherent impls. This is not meant to be used outside of coherence;
2731 /// rather, you should request the vector for a specific type via
2732 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2733 /// (constructing this map requires touching the entire crate).
2734 #[derive(Clone, Debug)]
2735 pub struct CrateInherentImpls {
2736 pub inherent_impls: DefIdMap<Rc<Vec<DefId>>>,
2739 /// A set of constraints that need to be satisfied in order for
2740 /// a type to be valid for destruction.
2741 #[derive(Clone, Debug)]
2742 pub struct DtorckConstraint<'tcx> {
2743 /// Types that are required to be alive in order for this
2744 /// type to be valid for destruction.
2745 pub outlives: Vec<ty::subst::Kind<'tcx>>,
2746 /// Types that could not be resolved: projections and params.
2747 pub dtorck_types: Vec<Ty<'tcx>>,
2750 impl<'tcx> FromIterator<DtorckConstraint<'tcx>> for DtorckConstraint<'tcx>
2752 fn from_iter<I: IntoIterator<Item=DtorckConstraint<'tcx>>>(iter: I) -> Self {
2753 let mut result = Self::empty();
2755 for constraint in iter {
2756 result.outlives.extend(constraint.outlives);
2757 result.dtorck_types.extend(constraint.dtorck_types);
2765 impl<'tcx> DtorckConstraint<'tcx> {
2766 fn empty() -> DtorckConstraint<'tcx> {
2769 dtorck_types: vec![]
2773 fn dedup<'a>(&mut self) {
2774 let mut outlives = FxHashSet();
2775 let mut dtorck_types = FxHashSet();
2777 self.outlives.retain(|&val| outlives.replace(val).is_none());
2778 self.dtorck_types.retain(|&val| dtorck_types.replace(val).is_none());
2782 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord)]
2783 pub struct SymbolName {
2784 // FIXME: we don't rely on interning or equality here - better have
2785 // this be a `&'tcx str`.
2786 pub name: InternedString
2789 impl Deref for SymbolName {
2792 fn deref(&self) -> &str { &self.name }
2795 impl fmt::Display for SymbolName {
2796 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2797 fmt::Display::fmt(&self.name, fmt)