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};
39 use std::collections::BTreeMap;
42 use std::hash::{Hash, Hasher};
43 use std::iter::FromIterator;
47 use std::vec::IntoIter;
49 use syntax::ast::{self, DUMMY_NODE_ID, Name, NodeId};
51 use syntax::symbol::{Symbol, InternedString};
52 use syntax_pos::{DUMMY_SP, Span};
53 use rustc_const_math::ConstInt;
55 use rustc_data_structures::accumulate_vec::IntoIter as AccIntoIter;
56 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
60 use hir::itemlikevisit::ItemLikeVisitor;
62 pub use self::sty::{Binder, DebruijnIndex};
63 pub use self::sty::{FnSig, PolyFnSig};
64 pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
65 pub use self::sty::{ClosureSubsts, TypeAndMut};
66 pub use self::sty::{TraitRef, TypeVariants, PolyTraitRef};
67 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
68 pub use self::sty::{ExistentialProjection, PolyExistentialProjection};
69 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
70 pub use self::sty::RegionKind;
71 pub use self::sty::Issue32330;
72 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid, SkolemizedRegionVid};
73 pub use self::sty::BoundRegion::*;
74 pub use self::sty::InferTy::*;
75 pub use self::sty::RegionKind::*;
76 pub use self::sty::TypeVariants::*;
78 pub use self::context::{TyCtxt, GlobalArenas, tls};
79 pub use self::context::{Lift, TypeckTables};
81 pub use self::instance::{Instance, InstanceDef};
83 pub use self::trait_def::{TraitDef, TraitFlags};
85 pub use self::maps::queries;
92 pub mod inhabitedness;
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 #[derive(Clone, Copy, Debug, RustcDecodable, RustcEncodable)]
313 pub struct MethodCallee<'tcx> {
314 /// Impl method ID, for inherent methods, or trait method ID, otherwise.
317 pub substs: &'tcx Substs<'tcx>
320 /// With method calls, we store some extra information in
321 /// side tables (i.e method_map). We use
322 /// MethodCall as a key to index into these tables instead of
323 /// just directly using the expression's NodeId. The reason
324 /// for this being that we may apply adjustments (coercions)
325 /// with the resulting expression also needing to use the
326 /// side tables. The problem with this is that we don't
327 /// assign a separate NodeId to this new expression
328 /// and so it would clash with the base expression if both
329 /// needed to add to the side tables. Thus to disambiguate
330 /// we also keep track of whether there's an adjustment in
332 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
333 pub struct MethodCall {
339 pub fn expr(id: NodeId) -> MethodCall {
346 pub fn autoderef(expr_id: NodeId, autoderef: u32) -> MethodCall {
349 autoderef: 1 + autoderef
354 // maps from an expression id that corresponds to a method call to the details
355 // of the method to be invoked
356 pub type MethodMap<'tcx> = FxHashMap<MethodCall, MethodCallee<'tcx>>;
358 // Contains information needed to resolve types and (in the future) look up
359 // the types of AST nodes.
360 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
361 pub struct CReaderCacheKey {
366 /// Describes the fragment-state associated with a NodeId.
368 /// Currently only unfragmented paths have entries in the table,
369 /// but longer-term this enum is expected to expand to also
370 /// include data for fragmented paths.
371 #[derive(Copy, Clone, Debug)]
372 pub enum FragmentInfo {
373 Moved { var: NodeId, move_expr: NodeId },
374 Assigned { var: NodeId, assign_expr: NodeId, assignee_id: NodeId },
377 // Flags that we track on types. These flags are propagated upwards
378 // through the type during type construction, so that we can quickly
379 // check whether the type has various kinds of types in it without
380 // recursing over the type itself.
382 flags TypeFlags: u32 {
383 const HAS_PARAMS = 1 << 0,
384 const HAS_SELF = 1 << 1,
385 const HAS_TY_INFER = 1 << 2,
386 const HAS_RE_INFER = 1 << 3,
387 const HAS_RE_SKOL = 1 << 4,
388 const HAS_RE_EARLY_BOUND = 1 << 5,
389 const HAS_FREE_REGIONS = 1 << 6,
390 const HAS_TY_ERR = 1 << 7,
391 const HAS_PROJECTION = 1 << 8,
392 const HAS_TY_CLOSURE = 1 << 9,
394 // true if there are "names" of types and regions and so forth
395 // that are local to a particular fn
396 const HAS_LOCAL_NAMES = 1 << 10,
398 // Present if the type belongs in a local type context.
399 // Only set for TyInfer other than Fresh.
400 const KEEP_IN_LOCAL_TCX = 1 << 11,
402 // Is there a projection that does not involve a bound region?
403 // Currently we can't normalize projections w/ bound regions.
404 const HAS_NORMALIZABLE_PROJECTION = 1 << 12,
406 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
407 TypeFlags::HAS_SELF.bits |
408 TypeFlags::HAS_RE_EARLY_BOUND.bits,
410 // Flags representing the nominal content of a type,
411 // computed by FlagsComputation. If you add a new nominal
412 // flag, it should be added here too.
413 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
414 TypeFlags::HAS_SELF.bits |
415 TypeFlags::HAS_TY_INFER.bits |
416 TypeFlags::HAS_RE_INFER.bits |
417 TypeFlags::HAS_RE_SKOL.bits |
418 TypeFlags::HAS_RE_EARLY_BOUND.bits |
419 TypeFlags::HAS_FREE_REGIONS.bits |
420 TypeFlags::HAS_TY_ERR.bits |
421 TypeFlags::HAS_PROJECTION.bits |
422 TypeFlags::HAS_TY_CLOSURE.bits |
423 TypeFlags::HAS_LOCAL_NAMES.bits |
424 TypeFlags::KEEP_IN_LOCAL_TCX.bits,
426 // Caches for type_is_sized, type_moves_by_default
427 const SIZEDNESS_CACHED = 1 << 16,
428 const IS_SIZED = 1 << 17,
429 const MOVENESS_CACHED = 1 << 18,
430 const MOVES_BY_DEFAULT = 1 << 19,
431 const FREEZENESS_CACHED = 1 << 20,
432 const IS_FREEZE = 1 << 21,
433 const NEEDS_DROP_CACHED = 1 << 22,
434 const NEEDS_DROP = 1 << 23,
438 pub struct TyS<'tcx> {
439 pub sty: TypeVariants<'tcx>,
440 pub flags: Cell<TypeFlags>,
442 // the maximal depth of any bound regions appearing in this type.
446 impl<'tcx> PartialEq for TyS<'tcx> {
448 fn eq(&self, other: &TyS<'tcx>) -> bool {
449 // (self as *const _) == (other as *const _)
450 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
453 impl<'tcx> Eq for TyS<'tcx> {}
455 impl<'tcx> Hash for TyS<'tcx> {
456 fn hash<H: Hasher>(&self, s: &mut H) {
457 (self as *const TyS).hash(s)
461 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for ty::TyS<'tcx> {
462 fn hash_stable<W: StableHasherResult>(&self,
463 hcx: &mut StableHashingContext<'a, 'tcx>,
464 hasher: &mut StableHasher<W>) {
468 // The other fields just provide fast access to information that is
469 // also contained in `sty`, so no need to hash them.
474 sty.hash_stable(hcx, hasher);
478 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
480 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
481 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
483 /// A wrapper for slices with the additional invariant
484 /// that the slice is interned and no other slice with
485 /// the same contents can exist in the same context.
486 /// This means we can use pointer + length for both
487 /// equality comparisons and hashing.
488 #[derive(Debug, RustcEncodable)]
489 pub struct Slice<T>([T]);
491 impl<T> PartialEq for Slice<T> {
493 fn eq(&self, other: &Slice<T>) -> bool {
494 (&self.0 as *const [T]) == (&other.0 as *const [T])
497 impl<T> Eq for Slice<T> {}
499 impl<T> Hash for Slice<T> {
500 fn hash<H: Hasher>(&self, s: &mut H) {
501 (self.as_ptr(), self.len()).hash(s)
505 impl<T> Deref for Slice<T> {
507 fn deref(&self) -> &[T] {
512 impl<'a, T> IntoIterator for &'a Slice<T> {
514 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
515 fn into_iter(self) -> Self::IntoIter {
520 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {}
523 pub fn empty<'a>() -> &'a Slice<T> {
525 mem::transmute(slice::from_raw_parts(0x1 as *const T, 0))
530 /// Upvars do not get their own node-id. Instead, we use the pair of
531 /// the original var id (that is, the root variable that is referenced
532 /// by the upvar) and the id of the closure expression.
533 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
536 pub closure_expr_id: NodeId,
539 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
540 pub enum BorrowKind {
541 /// Data must be immutable and is aliasable.
544 /// Data must be immutable but not aliasable. This kind of borrow
545 /// cannot currently be expressed by the user and is used only in
546 /// implicit closure bindings. It is needed when the closure
547 /// is borrowing or mutating a mutable referent, e.g.:
549 /// let x: &mut isize = ...;
550 /// let y = || *x += 5;
552 /// If we were to try to translate this closure into a more explicit
553 /// form, we'd encounter an error with the code as written:
555 /// struct Env { x: & &mut isize }
556 /// let x: &mut isize = ...;
557 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
558 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
560 /// This is then illegal because you cannot mutate a `&mut` found
561 /// in an aliasable location. To solve, you'd have to translate with
562 /// an `&mut` borrow:
564 /// struct Env { x: & &mut isize }
565 /// let x: &mut isize = ...;
566 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
567 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
569 /// Now the assignment to `**env.x` is legal, but creating a
570 /// mutable pointer to `x` is not because `x` is not mutable. We
571 /// could fix this by declaring `x` as `let mut x`. This is ok in
572 /// user code, if awkward, but extra weird for closures, since the
573 /// borrow is hidden.
575 /// So we introduce a "unique imm" borrow -- the referent is
576 /// immutable, but not aliasable. This solves the problem. For
577 /// simplicity, we don't give users the way to express this
578 /// borrow, it's just used when translating closures.
581 /// Data is mutable and not aliasable.
585 /// Information describing the capture of an upvar. This is computed
586 /// during `typeck`, specifically by `regionck`.
587 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
588 pub enum UpvarCapture<'tcx> {
589 /// Upvar is captured by value. This is always true when the
590 /// closure is labeled `move`, but can also be true in other cases
591 /// depending on inference.
594 /// Upvar is captured by reference.
595 ByRef(UpvarBorrow<'tcx>),
598 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
599 pub struct UpvarBorrow<'tcx> {
600 /// The kind of borrow: by-ref upvars have access to shared
601 /// immutable borrows, which are not part of the normal language
603 pub kind: BorrowKind,
605 /// Region of the resulting reference.
606 pub region: ty::Region<'tcx>,
609 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
611 #[derive(Copy, Clone)]
612 pub struct ClosureUpvar<'tcx> {
618 #[derive(Clone, Copy, PartialEq)]
619 pub enum IntVarValue {
621 UintType(ast::UintTy),
624 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
625 pub struct TypeParameterDef {
629 pub has_default: bool,
630 pub object_lifetime_default: ObjectLifetimeDefault,
632 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
633 /// on generic parameter `T`, asserts data behind the parameter
634 /// `T` won't be accessed during the parent type's `Drop` impl.
635 pub pure_wrt_drop: bool,
638 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
639 pub struct RegionParameterDef {
643 pub issue_32330: Option<ty::Issue32330>,
645 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
646 /// on generic parameter `'a`, asserts data of lifetime `'a`
647 /// won't be accessed during the parent type's `Drop` impl.
648 pub pure_wrt_drop: bool,
651 impl RegionParameterDef {
652 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
653 ty::EarlyBoundRegion {
659 pub fn to_bound_region(&self) -> ty::BoundRegion {
660 ty::BoundRegion::BrNamed(self.def_id, self.name)
664 /// Information about the formal type/lifetime parameters associated
665 /// with an item or method. Analogous to hir::Generics.
666 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
667 pub struct Generics {
668 pub parent: Option<DefId>,
669 pub parent_regions: u32,
670 pub parent_types: u32,
671 pub regions: Vec<RegionParameterDef>,
672 pub types: Vec<TypeParameterDef>,
674 /// Reverse map to each `TypeParameterDef`'s `index` field, from
675 /// `def_id.index` (`def_id.krate` is the same as the item's).
676 pub type_param_to_index: BTreeMap<DefIndex, u32>,
682 pub fn parent_count(&self) -> usize {
683 self.parent_regions as usize + self.parent_types as usize
686 pub fn own_count(&self) -> usize {
687 self.regions.len() + self.types.len()
690 pub fn count(&self) -> usize {
691 self.parent_count() + self.own_count()
694 pub fn region_param(&self, param: &EarlyBoundRegion) -> &RegionParameterDef {
695 assert_eq!(self.parent_count(), 0);
696 &self.regions[param.index as usize - self.has_self as usize]
699 pub fn type_param(&self, param: &ParamTy) -> &TypeParameterDef {
700 assert_eq!(self.parent_count(), 0);
701 &self.types[param.idx as usize - self.has_self as usize - self.regions.len()]
705 /// Bounds on generics.
706 #[derive(Clone, Default)]
707 pub struct GenericPredicates<'tcx> {
708 pub parent: Option<DefId>,
709 pub predicates: Vec<Predicate<'tcx>>,
712 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
713 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
715 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
716 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
717 -> InstantiatedPredicates<'tcx> {
718 let mut instantiated = InstantiatedPredicates::empty();
719 self.instantiate_into(tcx, &mut instantiated, substs);
722 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
723 -> InstantiatedPredicates<'tcx> {
724 InstantiatedPredicates {
725 predicates: self.predicates.subst(tcx, substs)
729 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
730 instantiated: &mut InstantiatedPredicates<'tcx>,
731 substs: &Substs<'tcx>) {
732 if let Some(def_id) = self.parent {
733 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
735 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
738 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
739 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
740 -> InstantiatedPredicates<'tcx>
742 assert_eq!(self.parent, None);
743 InstantiatedPredicates {
744 predicates: self.predicates.iter().map(|pred| {
745 pred.subst_supertrait(tcx, poly_trait_ref)
751 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
752 pub enum Predicate<'tcx> {
753 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
754 /// the `Self` type of the trait reference and `A`, `B`, and `C`
755 /// would be the type parameters.
756 Trait(PolyTraitPredicate<'tcx>),
758 /// where `T1 == T2`.
759 Equate(PolyEquatePredicate<'tcx>),
762 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
765 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
767 /// where <T as TraitRef>::Name == X, approximately.
768 /// See `ProjectionPredicate` struct for details.
769 Projection(PolyProjectionPredicate<'tcx>),
772 WellFormed(Ty<'tcx>),
774 /// trait must be object-safe
777 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
778 /// for some substitutions `...` and T being a closure type.
779 /// Satisfied (or refuted) once we know the closure's kind.
780 ClosureKind(DefId, ClosureKind),
783 Subtype(PolySubtypePredicate<'tcx>),
786 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
787 /// Performs a substitution suitable for going from a
788 /// poly-trait-ref to supertraits that must hold if that
789 /// poly-trait-ref holds. This is slightly different from a normal
790 /// substitution in terms of what happens with bound regions. See
791 /// lengthy comment below for details.
792 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
793 trait_ref: &ty::PolyTraitRef<'tcx>)
794 -> ty::Predicate<'tcx>
796 // The interaction between HRTB and supertraits is not entirely
797 // obvious. Let me walk you (and myself) through an example.
799 // Let's start with an easy case. Consider two traits:
801 // trait Foo<'a> : Bar<'a,'a> { }
802 // trait Bar<'b,'c> { }
804 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
805 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
806 // knew that `Foo<'x>` (for any 'x) then we also know that
807 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
808 // normal substitution.
810 // In terms of why this is sound, the idea is that whenever there
811 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
812 // holds. So if there is an impl of `T:Foo<'a>` that applies to
813 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
816 // Another example to be careful of is this:
818 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
819 // trait Bar1<'b,'c> { }
821 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
822 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
823 // reason is similar to the previous example: any impl of
824 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
825 // basically we would want to collapse the bound lifetimes from
826 // the input (`trait_ref`) and the supertraits.
828 // To achieve this in practice is fairly straightforward. Let's
829 // consider the more complicated scenario:
831 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
832 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
833 // where both `'x` and `'b` would have a DB index of 1.
834 // The substitution from the input trait-ref is therefore going to be
835 // `'a => 'x` (where `'x` has a DB index of 1).
836 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
837 // early-bound parameter and `'b' is a late-bound parameter with a
839 // - If we replace `'a` with `'x` from the input, it too will have
840 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
841 // just as we wanted.
843 // There is only one catch. If we just apply the substitution `'a
844 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
845 // adjust the DB index because we substituting into a binder (it
846 // tries to be so smart...) resulting in `for<'x> for<'b>
847 // Bar1<'x,'b>` (we have no syntax for this, so use your
848 // imagination). Basically the 'x will have DB index of 2 and 'b
849 // will have DB index of 1. Not quite what we want. So we apply
850 // the substitution to the *contents* of the trait reference,
851 // rather than the trait reference itself (put another way, the
852 // substitution code expects equal binding levels in the values
853 // from the substitution and the value being substituted into, and
854 // this trick achieves that).
856 let substs = &trait_ref.0.substs;
858 Predicate::Trait(ty::Binder(ref data)) =>
859 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
860 Predicate::Equate(ty::Binder(ref data)) =>
861 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
862 Predicate::Subtype(ty::Binder(ref data)) =>
863 Predicate::Subtype(ty::Binder(data.subst(tcx, substs))),
864 Predicate::RegionOutlives(ty::Binder(ref data)) =>
865 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
866 Predicate::TypeOutlives(ty::Binder(ref data)) =>
867 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
868 Predicate::Projection(ty::Binder(ref data)) =>
869 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
870 Predicate::WellFormed(data) =>
871 Predicate::WellFormed(data.subst(tcx, substs)),
872 Predicate::ObjectSafe(trait_def_id) =>
873 Predicate::ObjectSafe(trait_def_id),
874 Predicate::ClosureKind(closure_def_id, kind) =>
875 Predicate::ClosureKind(closure_def_id, kind),
880 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
881 pub struct TraitPredicate<'tcx> {
882 pub trait_ref: TraitRef<'tcx>
884 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
886 impl<'tcx> TraitPredicate<'tcx> {
887 pub fn def_id(&self) -> DefId {
888 self.trait_ref.def_id
891 /// Creates the dep-node for selecting/evaluating this trait reference.
892 fn dep_node(&self) -> DepNode<DefId> {
893 // Extact the trait-def and first def-id from inputs. See the
894 // docs for `DepNode::TraitSelect` for more information.
895 let trait_def_id = self.def_id();
898 .flat_map(|t| t.walk())
899 .filter_map(|t| match t.sty {
900 ty::TyAdt(adt_def, _) => Some(adt_def.did),
904 .unwrap_or(trait_def_id);
905 DepNode::TraitSelect {
906 trait_def_id: trait_def_id,
907 input_def_id: input_def_id
911 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
912 self.trait_ref.input_types()
915 pub fn self_ty(&self) -> Ty<'tcx> {
916 self.trait_ref.self_ty()
920 impl<'tcx> PolyTraitPredicate<'tcx> {
921 pub fn def_id(&self) -> DefId {
922 // ok to skip binder since trait def-id does not care about regions
926 pub fn dep_node(&self) -> DepNode<DefId> {
927 // ok to skip binder since depnode does not care about regions
932 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
933 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
934 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
936 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
937 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
938 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
939 pub type PolyRegionOutlivesPredicate<'tcx> = PolyOutlivesPredicate<ty::Region<'tcx>,
941 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
943 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
944 pub struct SubtypePredicate<'tcx> {
945 pub a_is_expected: bool,
949 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
951 /// This kind of predicate has no *direct* correspondent in the
952 /// syntax, but it roughly corresponds to the syntactic forms:
954 /// 1. `T : TraitRef<..., Item=Type>`
955 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
957 /// In particular, form #1 is "desugared" to the combination of a
958 /// normal trait predicate (`T : TraitRef<...>`) and one of these
959 /// predicates. Form #2 is a broader form in that it also permits
960 /// equality between arbitrary types. Processing an instance of Form
961 /// #2 eventually yields one of these `ProjectionPredicate`
962 /// instances to normalize the LHS.
963 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
964 pub struct ProjectionPredicate<'tcx> {
965 pub projection_ty: ProjectionTy<'tcx>,
969 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
971 impl<'tcx> PolyProjectionPredicate<'tcx> {
972 pub fn item_name(&self) -> Name {
973 self.0.projection_ty.item_name // safe to skip the binder to access a name
977 pub trait ToPolyTraitRef<'tcx> {
978 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
981 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
982 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
983 assert!(!self.has_escaping_regions());
984 ty::Binder(self.clone())
988 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
989 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
990 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
994 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
995 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
996 // Note: unlike with TraitRef::to_poly_trait_ref(),
997 // self.0.trait_ref is permitted to have escaping regions.
998 // This is because here `self` has a `Binder` and so does our
999 // return value, so we are preserving the number of binding
1001 ty::Binder(self.0.projection_ty.trait_ref)
1005 pub trait ToPredicate<'tcx> {
1006 fn to_predicate(&self) -> Predicate<'tcx>;
1009 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1010 fn to_predicate(&self) -> Predicate<'tcx> {
1011 // we're about to add a binder, so let's check that we don't
1012 // accidentally capture anything, or else that might be some
1013 // weird debruijn accounting.
1014 assert!(!self.has_escaping_regions());
1016 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
1017 trait_ref: self.clone()
1022 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1023 fn to_predicate(&self) -> Predicate<'tcx> {
1024 ty::Predicate::Trait(self.to_poly_trait_predicate())
1028 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
1029 fn to_predicate(&self) -> Predicate<'tcx> {
1030 Predicate::Equate(self.clone())
1034 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1035 fn to_predicate(&self) -> Predicate<'tcx> {
1036 Predicate::RegionOutlives(self.clone())
1040 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1041 fn to_predicate(&self) -> Predicate<'tcx> {
1042 Predicate::TypeOutlives(self.clone())
1046 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1047 fn to_predicate(&self) -> Predicate<'tcx> {
1048 Predicate::Projection(self.clone())
1052 impl<'tcx> Predicate<'tcx> {
1053 /// Iterates over the types in this predicate. Note that in all
1054 /// cases this is skipping over a binder, so late-bound regions
1055 /// with depth 0 are bound by the predicate.
1056 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1057 let vec: Vec<_> = match *self {
1058 ty::Predicate::Trait(ref data) => {
1059 data.skip_binder().input_types().collect()
1061 ty::Predicate::Equate(ty::Binder(ref data)) => {
1062 vec![data.0, data.1]
1064 ty::Predicate::Subtype(ty::Binder(SubtypePredicate { a, b, a_is_expected: _ })) => {
1067 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
1070 ty::Predicate::RegionOutlives(..) => {
1073 ty::Predicate::Projection(ref data) => {
1074 let trait_inputs = data.0.projection_ty.trait_ref.input_types();
1075 trait_inputs.chain(Some(data.0.ty)).collect()
1077 ty::Predicate::WellFormed(data) => {
1080 ty::Predicate::ObjectSafe(_trait_def_id) => {
1083 ty::Predicate::ClosureKind(_closure_def_id, _kind) => {
1088 // The only reason to collect into a vector here is that I was
1089 // too lazy to make the full (somewhat complicated) iterator
1090 // type that would be needed here. But I wanted this fn to
1091 // return an iterator conceptually, rather than a `Vec`, so as
1092 // to be closer to `Ty::walk`.
1096 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1098 Predicate::Trait(ref t) => {
1099 Some(t.to_poly_trait_ref())
1101 Predicate::Projection(..) |
1102 Predicate::Equate(..) |
1103 Predicate::Subtype(..) |
1104 Predicate::RegionOutlives(..) |
1105 Predicate::WellFormed(..) |
1106 Predicate::ObjectSafe(..) |
1107 Predicate::ClosureKind(..) |
1108 Predicate::TypeOutlives(..) => {
1115 /// Represents the bounds declared on a particular set of type
1116 /// parameters. Should eventually be generalized into a flag list of
1117 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1118 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1119 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1120 /// the `GenericPredicates` are expressed in terms of the bound type
1121 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1122 /// represented a set of bounds for some particular instantiation,
1123 /// meaning that the generic parameters have been substituted with
1128 /// struct Foo<T,U:Bar<T>> { ... }
1130 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1131 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1132 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1133 /// [usize:Bar<isize>]]`.
1135 pub struct InstantiatedPredicates<'tcx> {
1136 pub predicates: Vec<Predicate<'tcx>>,
1139 impl<'tcx> InstantiatedPredicates<'tcx> {
1140 pub fn empty() -> InstantiatedPredicates<'tcx> {
1141 InstantiatedPredicates { predicates: vec![] }
1144 pub fn is_empty(&self) -> bool {
1145 self.predicates.is_empty()
1149 /// When type checking, we use the `ParameterEnvironment` to track
1150 /// details about the type/lifetime parameters that are in scope.
1151 /// It primarily stores the bounds information.
1153 /// Note: This information might seem to be redundant with the data in
1154 /// `tcx.ty_param_defs`, but it is not. That table contains the
1155 /// parameter definitions from an "outside" perspective, but this
1156 /// struct will contain the bounds for a parameter as seen from inside
1157 /// the function body. Currently the only real distinction is that
1158 /// bound lifetime parameters are replaced with free ones, but in the
1159 /// future I hope to refine the representation of types so as to make
1160 /// more distinctions clearer.
1162 pub struct ParameterEnvironment<'tcx> {
1163 /// See `construct_free_substs` for details.
1164 pub free_substs: &'tcx Substs<'tcx>,
1166 /// Each type parameter has an implicit region bound that
1167 /// indicates it must outlive at least the function body (the user
1168 /// may specify stronger requirements). This field indicates the
1169 /// region of the callee. If it is `None`, then the parameter
1170 /// environment is for an item or something where the "callee" is
1172 pub implicit_region_bound: Option<ty::Region<'tcx>>,
1174 /// Obligations that the caller must satisfy. This is basically
1175 /// the set of bounds on the in-scope type parameters, translated
1176 /// into Obligations, and elaborated and normalized.
1177 pub caller_bounds: &'tcx [ty::Predicate<'tcx>],
1179 /// Scope that is attached to free regions for this scope. This is
1180 /// usually the id of the fn body, but for more abstract scopes
1181 /// like structs we use None or the item extent.
1183 /// FIXME(#3696). It would be nice to refactor so that free
1184 /// regions don't have this implicit scope and instead introduce
1185 /// relationships in the environment.
1186 pub free_id_outlive: Option<CodeExtent<'tcx>>,
1188 /// A cache for `moves_by_default`.
1189 pub is_copy_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1191 /// A cache for `type_is_sized`
1192 pub is_sized_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1194 /// A cache for `type_is_freeze`
1195 pub is_freeze_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1198 impl<'a, 'tcx> ParameterEnvironment<'tcx> {
1199 pub fn with_caller_bounds(&self,
1200 caller_bounds: &'tcx [ty::Predicate<'tcx>])
1201 -> ParameterEnvironment<'tcx>
1203 ParameterEnvironment {
1204 free_substs: self.free_substs,
1205 implicit_region_bound: self.implicit_region_bound,
1206 caller_bounds: caller_bounds,
1207 free_id_outlive: self.free_id_outlive,
1208 is_copy_cache: RefCell::new(FxHashMap()),
1209 is_sized_cache: RefCell::new(FxHashMap()),
1210 is_freeze_cache: RefCell::new(FxHashMap()),
1214 /// Construct a parameter environment given an item, impl item, or trait item
1215 pub fn for_item(tcx: TyCtxt<'a, 'tcx, 'tcx>, id: NodeId)
1216 -> ParameterEnvironment<'tcx> {
1217 match tcx.hir.find(id) {
1218 Some(hir_map::NodeImplItem(ref impl_item)) => {
1219 match impl_item.node {
1220 hir::ImplItemKind::Type(_) | hir::ImplItemKind::Const(..) => {
1221 // associated types don't have their own entry (for some reason),
1222 // so for now just grab environment for the impl
1223 let impl_id = tcx.hir.get_parent(id);
1224 let impl_def_id = tcx.hir.local_def_id(impl_id);
1225 tcx.construct_parameter_environment(impl_item.span,
1227 Some(tcx.item_extent(id)))
1229 hir::ImplItemKind::Method(_, ref body) => {
1230 tcx.construct_parameter_environment(
1232 tcx.hir.local_def_id(id),
1233 Some(tcx.call_site_extent(id, body.node_id)))
1237 Some(hir_map::NodeTraitItem(trait_item)) => {
1238 match trait_item.node {
1239 hir::TraitItemKind::Type(..) | hir::TraitItemKind::Const(..) => {
1240 // associated types don't have their own entry (for some reason),
1241 // so for now just grab environment for the trait
1242 let trait_id = tcx.hir.get_parent(id);
1243 let trait_def_id = tcx.hir.local_def_id(trait_id);
1244 tcx.construct_parameter_environment(trait_item.span,
1246 Some(tcx.item_extent(id)))
1248 hir::TraitItemKind::Method(_, ref body) => {
1249 // Use call-site for extent (unless this is a
1250 // trait method with no default; then fallback
1251 // to the method id).
1252 let extent = if let hir::TraitMethod::Provided(body_id) = *body {
1253 // default impl: use call_site extent as free_id_outlive bound.
1254 tcx.call_site_extent(id, body_id.node_id)
1256 // no default impl: use item extent as free_id_outlive bound.
1259 tcx.construct_parameter_environment(
1261 tcx.hir.local_def_id(id),
1266 Some(hir_map::NodeItem(item)) => {
1268 hir::ItemFn(.., body_id) => {
1269 // We assume this is a function.
1270 let fn_def_id = tcx.hir.local_def_id(id);
1272 tcx.construct_parameter_environment(
1275 Some(tcx.call_site_extent(id, body_id.node_id)))
1278 hir::ItemStruct(..) |
1279 hir::ItemUnion(..) |
1282 hir::ItemConst(..) |
1283 hir::ItemStatic(..) => {
1284 let def_id = tcx.hir.local_def_id(id);
1285 tcx.construct_parameter_environment(item.span,
1287 Some(tcx.item_extent(id)))
1289 hir::ItemTrait(..) => {
1290 let def_id = tcx.hir.local_def_id(id);
1291 tcx.construct_parameter_environment(item.span,
1293 Some(tcx.item_extent(id)))
1296 span_bug!(item.span,
1297 "ParameterEnvironment::for_item():
1298 can't create a parameter \
1299 environment for this kind of item")
1303 Some(hir_map::NodeExpr(expr)) => {
1304 // This is a convenience to allow closures to work.
1305 if let hir::ExprClosure(.., body, _) = expr.node {
1306 let def_id = tcx.hir.local_def_id(id);
1307 let base_def_id = tcx.closure_base_def_id(def_id);
1308 tcx.construct_parameter_environment(
1311 Some(tcx.call_site_extent(id, body.node_id)))
1313 tcx.empty_parameter_environment()
1316 Some(hir_map::NodeForeignItem(item)) => {
1317 let def_id = tcx.hir.local_def_id(id);
1318 tcx.construct_parameter_environment(item.span,
1322 Some(hir_map::NodeStructCtor(..)) |
1323 Some(hir_map::NodeVariant(..)) => {
1324 let def_id = tcx.hir.local_def_id(id);
1325 tcx.construct_parameter_environment(tcx.hir.span(id),
1330 bug!("ParameterEnvironment::from_item(): \
1331 `{}` = {:?} is unsupported",
1332 tcx.hir.node_to_string(id), it)
1338 #[derive(Copy, Clone, Debug)]
1339 pub struct Destructor {
1340 /// The def-id of the destructor method
1345 flags AdtFlags: u32 {
1346 const NO_ADT_FLAGS = 0,
1347 const IS_ENUM = 1 << 0,
1348 const IS_PHANTOM_DATA = 1 << 1,
1349 const IS_FUNDAMENTAL = 1 << 2,
1350 const IS_UNION = 1 << 3,
1351 const IS_BOX = 1 << 4,
1356 pub struct VariantDef {
1357 /// The variant's DefId. If this is a tuple-like struct,
1358 /// this is the DefId of the struct's ctor.
1360 pub name: Name, // struct's name if this is a struct
1361 pub discr: VariantDiscr,
1362 pub fields: Vec<FieldDef>,
1363 pub ctor_kind: CtorKind,
1366 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1367 pub enum VariantDiscr {
1368 /// Explicit value for this variant, i.e. `X = 123`.
1369 /// The `DefId` corresponds to the embedded constant.
1372 /// The previous variant's discriminant plus one.
1373 /// For efficiency reasons, the distance from the
1374 /// last `Explicit` discriminant is being stored,
1375 /// or `0` for the first variant, if it has none.
1380 pub struct FieldDef {
1383 pub vis: Visibility,
1386 /// The definition of an abstract data type - a struct or enum.
1388 /// These are all interned (by intern_adt_def) into the adt_defs
1392 pub variants: Vec<VariantDef>,
1394 pub repr: ReprOptions,
1397 impl PartialEq for AdtDef {
1398 // AdtDef are always interned and this is part of TyS equality
1400 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1403 impl Eq for AdtDef {}
1405 impl Hash for AdtDef {
1407 fn hash<H: Hasher>(&self, s: &mut H) {
1408 (self as *const AdtDef).hash(s)
1412 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1413 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1418 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1421 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for AdtDef {
1422 fn hash_stable<W: StableHasherResult>(&self,
1423 hcx: &mut StableHashingContext<'a, 'tcx>,
1424 hasher: &mut StableHasher<W>) {
1432 did.hash_stable(hcx, hasher);
1433 variants.hash_stable(hcx, hasher);
1434 flags.hash_stable(hcx, hasher);
1435 repr.hash_stable(hcx, hasher);
1439 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1440 pub enum AdtKind { Struct, Union, Enum }
1443 #[derive(RustcEncodable, RustcDecodable, Default)]
1444 flags ReprFlags: u8 {
1445 const IS_C = 1 << 0,
1446 const IS_PACKED = 1 << 1,
1447 const IS_SIMD = 1 << 2,
1448 // Internal only for now. If true, don't reorder fields.
1449 const IS_LINEAR = 1 << 3,
1451 // Any of these flags being set prevent field reordering optimisation.
1452 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1453 ReprFlags::IS_PACKED.bits |
1454 ReprFlags::IS_SIMD.bits |
1455 ReprFlags::IS_LINEAR.bits,
1459 impl_stable_hash_for!(struct ReprFlags {
1465 /// Represents the repr options provided by the user,
1466 #[derive(Copy, Clone, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1467 pub struct ReprOptions {
1468 pub int: Option<attr::IntType>,
1470 pub flags: ReprFlags,
1473 impl_stable_hash_for!(struct ReprOptions {
1480 pub fn new(tcx: TyCtxt, did: DefId) -> ReprOptions {
1481 let mut flags = ReprFlags::empty();
1482 let mut size = None;
1483 let mut max_align = 0;
1484 for attr in tcx.get_attrs(did).iter() {
1485 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1486 flags.insert(match r {
1487 attr::ReprExtern => ReprFlags::IS_C,
1488 attr::ReprPacked => ReprFlags::IS_PACKED,
1489 attr::ReprSimd => ReprFlags::IS_SIMD,
1490 attr::ReprInt(i) => {
1494 attr::ReprAlign(align) => {
1495 max_align = cmp::max(align, max_align);
1502 // FIXME(eddyb) This is deprecated and should be removed.
1503 if tcx.has_attr(did, "simd") {
1504 flags.insert(ReprFlags::IS_SIMD);
1507 // This is here instead of layout because the choice must make it into metadata.
1508 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1509 flags.insert(ReprFlags::IS_LINEAR);
1511 ReprOptions { int: size, align: max_align, flags: flags }
1515 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1517 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1519 pub fn packed(&self) -> bool { self.flags.contains(ReprFlags::IS_PACKED) }
1521 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1523 pub fn discr_type(&self) -> attr::IntType {
1524 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Is))
1527 /// Returns true if this `#[repr()]` should inhabit "smart enum
1528 /// layout" optimizations, such as representing `Foo<&T>` as a
1530 pub fn inhibit_enum_layout_opt(&self) -> bool {
1531 self.c() || self.int.is_some()
1535 impl<'a, 'gcx, 'tcx> AdtDef {
1539 variants: Vec<VariantDef>,
1540 repr: ReprOptions) -> Self {
1541 let mut flags = AdtFlags::NO_ADT_FLAGS;
1542 let attrs = tcx.get_attrs(did);
1543 if attr::contains_name(&attrs, "fundamental") {
1544 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1546 if Some(did) == tcx.lang_items.phantom_data() {
1547 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1549 if Some(did) == tcx.lang_items.owned_box() {
1550 flags = flags | AdtFlags::IS_BOX;
1553 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
1554 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
1555 AdtKind::Struct => {}
1566 pub fn is_struct(&self) -> bool {
1567 !self.is_union() && !self.is_enum()
1571 pub fn is_union(&self) -> bool {
1572 self.flags.intersects(AdtFlags::IS_UNION)
1576 pub fn is_enum(&self) -> bool {
1577 self.flags.intersects(AdtFlags::IS_ENUM)
1580 /// Returns the kind of the ADT - Struct or Enum.
1582 pub fn adt_kind(&self) -> AdtKind {
1585 } else if self.is_union() {
1592 pub fn descr(&self) -> &'static str {
1593 match self.adt_kind() {
1594 AdtKind::Struct => "struct",
1595 AdtKind::Union => "union",
1596 AdtKind::Enum => "enum",
1600 pub fn variant_descr(&self) -> &'static str {
1601 match self.adt_kind() {
1602 AdtKind::Struct => "struct",
1603 AdtKind::Union => "union",
1604 AdtKind::Enum => "variant",
1608 /// Returns whether this type is #[fundamental] for the purposes
1609 /// of coherence checking.
1611 pub fn is_fundamental(&self) -> bool {
1612 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
1615 /// Returns true if this is PhantomData<T>.
1617 pub fn is_phantom_data(&self) -> bool {
1618 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
1621 /// Returns true if this is Box<T>.
1623 pub fn is_box(&self) -> bool {
1624 self.flags.intersects(AdtFlags::IS_BOX)
1627 /// Returns whether this type has a destructor.
1628 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
1629 self.destructor(tcx).is_some()
1632 /// Asserts this is a struct and returns the struct's unique
1634 pub fn struct_variant(&self) -> &VariantDef {
1635 assert!(!self.is_enum());
1640 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
1641 tcx.predicates_of(self.did)
1644 /// Returns an iterator over all fields contained
1647 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
1648 self.variants.iter().flat_map(|v| v.fields.iter())
1652 pub fn is_univariant(&self) -> bool {
1653 self.variants.len() == 1
1656 pub fn is_payloadfree(&self) -> bool {
1657 !self.variants.is_empty() &&
1658 self.variants.iter().all(|v| v.fields.is_empty())
1661 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
1664 .find(|v| v.did == vid)
1665 .expect("variant_with_id: unknown variant")
1668 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1671 .position(|v| v.did == vid)
1672 .expect("variant_index_with_id: unknown variant")
1675 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
1677 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
1678 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
1679 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.struct_variant(),
1680 _ => bug!("unexpected def {:?} in variant_of_def", def)
1685 pub fn discriminants(&'a self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1686 -> impl Iterator<Item=ConstInt> + 'a {
1687 let repr_type = self.repr.discr_type();
1688 let initial = repr_type.initial_discriminant(tcx.global_tcx());
1689 let mut prev_discr = None::<ConstInt>;
1690 self.variants.iter().map(move |v| {
1691 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr());
1692 if let VariantDiscr::Explicit(expr_did) = v.discr {
1693 let substs = Substs::empty();
1694 match tcx.const_eval((expr_did, substs)) {
1695 Ok(ConstVal::Integral(v)) => {
1699 if !expr_did.is_local() {
1700 span_bug!(tcx.def_span(expr_did),
1701 "variant discriminant evaluation succeeded \
1702 in its crate but failed locally: {:?}", err);
1707 prev_discr = Some(discr);
1713 /// Compute the discriminant value used by a specific variant.
1714 /// Unlike `discriminants`, this is (amortized) constant-time,
1715 /// only doing at most one query for evaluating an explicit
1716 /// discriminant (the last one before the requested variant),
1717 /// assuming there are no constant-evaluation errors there.
1718 pub fn discriminant_for_variant(&self,
1719 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1720 variant_index: usize)
1722 let repr_type = self.repr.discr_type();
1723 let mut explicit_value = repr_type.initial_discriminant(tcx.global_tcx());
1724 let mut explicit_index = variant_index;
1726 match self.variants[explicit_index].discr {
1727 ty::VariantDiscr::Relative(0) => break,
1728 ty::VariantDiscr::Relative(distance) => {
1729 explicit_index -= distance;
1731 ty::VariantDiscr::Explicit(expr_did) => {
1732 let substs = Substs::empty();
1733 match tcx.const_eval((expr_did, substs)) {
1734 Ok(ConstVal::Integral(v)) => {
1739 if !expr_did.is_local() {
1740 span_bug!(tcx.def_span(expr_did),
1741 "variant discriminant evaluation succeeded \
1742 in its crate but failed locally: {:?}", err);
1744 if explicit_index == 0 {
1747 explicit_index -= 1;
1753 let discr = explicit_value.to_u128_unchecked()
1754 .wrapping_add((variant_index - explicit_index) as u128);
1756 attr::UnsignedInt(ty) => {
1757 ConstInt::new_unsigned_truncating(discr, ty,
1758 tcx.sess.target.uint_type)
1760 attr::SignedInt(ty) => {
1761 ConstInt::new_signed_truncating(discr as i128, ty,
1762 tcx.sess.target.int_type)
1767 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
1768 tcx.adt_destructor(self.did)
1771 /// Returns a list of types such that `Self: Sized` if and only
1772 /// if that type is Sized, or `TyErr` if this type is recursive.
1774 /// Oddly enough, checking that the sized-constraint is Sized is
1775 /// actually more expressive than checking all members:
1776 /// the Sized trait is inductive, so an associated type that references
1777 /// Self would prevent its containing ADT from being Sized.
1779 /// Due to normalization being eager, this applies even if
1780 /// the associated type is behind a pointer, e.g. issue #31299.
1781 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
1782 match queries::adt_sized_constraint::try_get(tcx, DUMMY_SP, self.did) {
1785 debug!("adt_sized_constraint: {:?} is recursive", self);
1786 // This should be reported as an error by `check_representable`.
1788 // Consider the type as Sized in the meanwhile to avoid
1790 tcx.intern_type_list(&[tcx.types.err])
1795 fn sized_constraint_for_ty(&self,
1796 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1799 let result = match ty.sty {
1800 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
1801 TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
1802 TyArray(..) | TyClosure(..) | TyNever => {
1806 TyStr | TyDynamic(..) | TySlice(_) | TyError => {
1807 // these are never sized - return the target type
1811 TyTuple(ref tys, _) => {
1814 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
1818 TyAdt(adt, substs) => {
1820 let adt_tys = adt.sized_constraint(tcx);
1821 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
1824 .map(|ty| ty.subst(tcx, substs))
1825 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
1829 TyProjection(..) | TyAnon(..) => {
1830 // must calculate explicitly.
1831 // FIXME: consider special-casing always-Sized projections
1836 // perf hack: if there is a `T: Sized` bound, then
1837 // we know that `T` is Sized and do not need to check
1840 let sized_trait = match tcx.lang_items.sized_trait() {
1842 _ => return vec![ty]
1844 let sized_predicate = Binder(TraitRef {
1845 def_id: sized_trait,
1846 substs: tcx.mk_substs_trait(ty, &[])
1848 let predicates = tcx.predicates_of(self.did).predicates;
1849 if predicates.into_iter().any(|p| p == sized_predicate) {
1857 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
1861 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
1866 impl<'a, 'gcx, 'tcx> VariantDef {
1868 pub fn find_field_named(&self,
1870 -> Option<&FieldDef> {
1871 self.fields.iter().find(|f| f.name == name)
1875 pub fn index_of_field_named(&self,
1878 self.fields.iter().position(|f| f.name == name)
1882 pub fn field_named(&self, name: ast::Name) -> &FieldDef {
1883 self.find_field_named(name).unwrap()
1887 impl<'a, 'gcx, 'tcx> FieldDef {
1888 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1889 tcx.type_of(self.did).subst(tcx, subst)
1893 /// Records the substitutions used to translate the polytype for an
1894 /// item into the monotype of an item reference.
1895 #[derive(Clone, RustcEncodable, RustcDecodable)]
1896 pub struct ItemSubsts<'tcx> {
1897 pub substs: &'tcx Substs<'tcx>,
1900 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1901 pub enum ClosureKind {
1902 // Warning: Ordering is significant here! The ordering is chosen
1903 // because the trait Fn is a subtrait of FnMut and so in turn, and
1904 // hence we order it so that Fn < FnMut < FnOnce.
1910 impl<'a, 'tcx> ClosureKind {
1911 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
1913 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
1914 ClosureKind::FnMut => {
1915 tcx.require_lang_item(FnMutTraitLangItem)
1917 ClosureKind::FnOnce => {
1918 tcx.require_lang_item(FnOnceTraitLangItem)
1923 /// True if this a type that impls this closure kind
1924 /// must also implement `other`.
1925 pub fn extends(self, other: ty::ClosureKind) -> bool {
1926 match (self, other) {
1927 (ClosureKind::Fn, ClosureKind::Fn) => true,
1928 (ClosureKind::Fn, ClosureKind::FnMut) => true,
1929 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
1930 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
1931 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
1932 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
1938 impl<'tcx> TyS<'tcx> {
1939 /// Iterator that walks `self` and any types reachable from
1940 /// `self`, in depth-first order. Note that just walks the types
1941 /// that appear in `self`, it does not descend into the fields of
1942 /// structs or variants. For example:
1945 /// isize => { isize }
1946 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
1947 /// [isize] => { [isize], isize }
1949 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
1950 TypeWalker::new(self)
1953 /// Iterator that walks the immediate children of `self`. Hence
1954 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
1955 /// (but not `i32`, like `walk`).
1956 pub fn walk_shallow(&'tcx self) -> AccIntoIter<walk::TypeWalkerArray<'tcx>> {
1957 walk::walk_shallow(self)
1960 /// Walks `ty` and any types appearing within `ty`, invoking the
1961 /// callback `f` on each type. If the callback returns false, then the
1962 /// children of the current type are ignored.
1964 /// Note: prefer `ty.walk()` where possible.
1965 pub fn maybe_walk<F>(&'tcx self, mut f: F)
1966 where F : FnMut(Ty<'tcx>) -> bool
1968 let mut walker = self.walk();
1969 while let Some(ty) = walker.next() {
1971 walker.skip_current_subtree();
1977 impl<'tcx> ItemSubsts<'tcx> {
1978 pub fn is_noop(&self) -> bool {
1979 self.substs.is_noop()
1983 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1984 pub enum LvaluePreference {
1989 impl LvaluePreference {
1990 pub fn from_mutbl(m: hir::Mutability) -> Self {
1992 hir::MutMutable => PreferMutLvalue,
1993 hir::MutImmutable => NoPreference,
1999 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2001 hir::MutMutable => MutBorrow,
2002 hir::MutImmutable => ImmBorrow,
2006 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2007 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2008 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2010 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2012 MutBorrow => hir::MutMutable,
2013 ImmBorrow => hir::MutImmutable,
2015 // We have no type corresponding to a unique imm borrow, so
2016 // use `&mut`. It gives all the capabilities of an `&uniq`
2017 // and hence is a safe "over approximation".
2018 UniqueImmBorrow => hir::MutMutable,
2022 pub fn to_user_str(&self) -> &'static str {
2024 MutBorrow => "mutable",
2025 ImmBorrow => "immutable",
2026 UniqueImmBorrow => "uniquely immutable",
2031 #[derive(Debug, Clone)]
2032 pub enum Attributes<'gcx> {
2033 Owned(Rc<[ast::Attribute]>),
2034 Borrowed(&'gcx [ast::Attribute])
2037 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2038 type Target = [ast::Attribute];
2040 fn deref(&self) -> &[ast::Attribute] {
2042 &Attributes::Owned(ref data) => &data,
2043 &Attributes::Borrowed(data) => data
2048 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2049 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2050 self.typeck_tables_of(self.hir.body_owner_def_id(body))
2053 /// Returns an iterator of the def-ids for all body-owners in this
2054 /// crate. If you would prefer to iterate over the bodies
2055 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
2056 pub fn body_owners(self) -> impl Iterator<Item = DefId> + 'a {
2060 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
2063 pub fn expr_span(self, id: NodeId) -> Span {
2064 match self.hir.find(id) {
2065 Some(hir_map::NodeExpr(e)) => {
2069 bug!("Node id {} is not an expr: {:?}", id, f);
2072 bug!("Node id {} is not present in the node map", id);
2077 pub fn local_var_name_str(self, id: NodeId) -> InternedString {
2078 match self.hir.find(id) {
2079 Some(hir_map::NodeLocal(pat)) => {
2081 hir::PatKind::Binding(_, _, ref path1, _) => path1.node.as_str(),
2083 bug!("Variable id {} maps to {:?}, not local", id, pat);
2087 r => bug!("Variable id {} maps to {:?}, not local", id, r),
2091 pub fn expr_is_lval(self, expr: &hir::Expr) -> bool {
2093 hir::ExprPath(hir::QPath::Resolved(_, ref path)) => {
2095 Def::Local(..) | Def::Upvar(..) | Def::Static(..) | Def::Err => true,
2100 hir::ExprType(ref e, _) => {
2101 self.expr_is_lval(e)
2104 hir::ExprUnary(hir::UnDeref, _) |
2105 hir::ExprField(..) |
2106 hir::ExprTupField(..) |
2107 hir::ExprIndex(..) => {
2111 // Partially qualified paths in expressions can only legally
2112 // refer to associated items which are always rvalues.
2113 hir::ExprPath(hir::QPath::TypeRelative(..)) |
2116 hir::ExprMethodCall(..) |
2117 hir::ExprStruct(..) |
2120 hir::ExprMatch(..) |
2121 hir::ExprClosure(..) |
2122 hir::ExprBlock(..) |
2123 hir::ExprRepeat(..) |
2124 hir::ExprArray(..) |
2125 hir::ExprBreak(..) |
2126 hir::ExprAgain(..) |
2128 hir::ExprWhile(..) |
2130 hir::ExprAssign(..) |
2131 hir::ExprInlineAsm(..) |
2132 hir::ExprAssignOp(..) |
2134 hir::ExprUnary(..) |
2136 hir::ExprAddrOf(..) |
2137 hir::ExprBinary(..) |
2138 hir::ExprCast(..) => {
2144 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2145 self.associated_items(id)
2146 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2150 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2151 self.associated_items(did).any(|item| {
2152 item.relevant_for_never()
2156 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2157 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2158 match self.hir.get(node_id) {
2159 hir_map::NodeTraitItem(_) | hir_map::NodeImplItem(_) => true,
2163 match self.describe_def(def_id).expect("no def for def-id") {
2164 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2169 if is_associated_item {
2170 Some(self.associated_item(def_id))
2176 fn associated_item_from_trait_item_ref(self,
2177 parent_def_id: DefId,
2178 parent_vis: &hir::Visibility,
2179 trait_item_ref: &hir::TraitItemRef)
2181 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2182 let (kind, has_self) = match trait_item_ref.kind {
2183 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2184 hir::AssociatedItemKind::Method { has_self } => {
2185 (ty::AssociatedKind::Method, has_self)
2187 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2191 name: trait_item_ref.name,
2193 // Visibility of trait items is inherited from their traits.
2194 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2195 defaultness: trait_item_ref.defaultness,
2197 container: TraitContainer(parent_def_id),
2198 method_has_self_argument: has_self
2202 fn associated_item_from_impl_item_ref(self,
2203 parent_def_id: DefId,
2204 impl_item_ref: &hir::ImplItemRef)
2206 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2207 let (kind, has_self) = match impl_item_ref.kind {
2208 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2209 hir::AssociatedItemKind::Method { has_self } => {
2210 (ty::AssociatedKind::Method, has_self)
2212 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2215 ty::AssociatedItem {
2216 name: impl_item_ref.name,
2218 // Visibility of trait impl items doesn't matter.
2219 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2220 defaultness: impl_item_ref.defaultness,
2222 container: ImplContainer(parent_def_id),
2223 method_has_self_argument: has_self
2227 #[inline] // FIXME(#35870) Avoid closures being unexported due to impl Trait.
2228 pub fn associated_items(self, def_id: DefId)
2229 -> impl Iterator<Item = ty::AssociatedItem> + 'a {
2230 let def_ids = self.associated_item_def_ids(def_id);
2231 (0..def_ids.len()).map(move |i| self.associated_item(def_ids[i]))
2234 /// Returns true if the impls are the same polarity and are implementing
2235 /// a trait which contains no items
2236 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2237 if !self.sess.features.borrow().overlapping_marker_traits {
2240 let trait1_is_empty = self.impl_trait_ref(def_id1)
2241 .map_or(false, |trait_ref| {
2242 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2244 let trait2_is_empty = self.impl_trait_ref(def_id2)
2245 .map_or(false, |trait_ref| {
2246 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2248 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2253 // Returns `ty::VariantDef` if `def` refers to a struct,
2254 // or variant or their constructors, panics otherwise.
2255 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2257 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2258 let enum_did = self.parent_def_id(did).unwrap();
2259 self.adt_def(enum_did).variant_with_id(did)
2261 Def::Struct(did) | Def::Union(did) => {
2262 self.adt_def(did).struct_variant()
2264 Def::StructCtor(ctor_did, ..) => {
2265 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2266 self.adt_def(did).struct_variant()
2268 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2272 pub fn def_key(self, id: DefId) -> hir_map::DefKey {
2274 self.hir.def_key(id)
2276 self.sess.cstore.def_key(id)
2280 /// Convert a `DefId` into its fully expanded `DefPath` (every
2281 /// `DefId` is really just an interned def-path).
2283 /// Note that if `id` is not local to this crate, the result will
2284 /// be a non-local `DefPath`.
2285 pub fn def_path(self, id: DefId) -> hir_map::DefPath {
2287 self.hir.def_path(id)
2289 self.sess.cstore.def_path(id)
2294 pub fn def_path_hash(self, def_id: DefId) -> u64 {
2295 if def_id.is_local() {
2296 self.hir.definitions().def_path_hash(def_id.index)
2298 self.sess.cstore.def_path_hash(def_id)
2302 pub fn vis_is_accessible_from(self, vis: Visibility, block: NodeId) -> bool {
2303 vis.is_accessible_from(self.hir.local_def_id(self.hir.get_module_parent(block)), self)
2306 pub fn item_name(self, id: DefId) -> ast::Name {
2307 if let Some(id) = self.hir.as_local_node_id(id) {
2309 } else if id.index == CRATE_DEF_INDEX {
2310 self.sess.cstore.original_crate_name(id.krate)
2312 let def_key = self.sess.cstore.def_key(id);
2313 // The name of a StructCtor is that of its struct parent.
2314 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2315 self.item_name(DefId {
2317 index: def_key.parent.unwrap()
2320 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2321 bug!("item_name: no name for {:?}", self.def_path(id));
2327 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2328 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2332 ty::InstanceDef::Item(did) => {
2333 self.optimized_mir(did)
2335 ty::InstanceDef::Intrinsic(..) |
2336 ty::InstanceDef::FnPtrShim(..) |
2337 ty::InstanceDef::Virtual(..) |
2338 ty::InstanceDef::ClosureOnceShim { .. } |
2339 ty::InstanceDef::DropGlue(..) => {
2340 self.mir_shims(instance)
2345 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2346 /// Returns None if there is no MIR for the DefId
2347 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2348 if self.is_mir_available(did) {
2349 Some(self.optimized_mir(did))
2355 /// Get the attributes of a definition.
2356 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2357 if let Some(id) = self.hir.as_local_node_id(did) {
2358 Attributes::Borrowed(self.hir.attrs(id))
2360 Attributes::Owned(self.item_attrs(did))
2364 /// Determine whether an item is annotated with an attribute
2365 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2366 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2369 pub fn trait_has_default_impl(self, trait_def_id: DefId) -> bool {
2370 let def = self.trait_def(trait_def_id);
2371 def.flags.get().intersects(TraitFlags::HAS_DEFAULT_IMPL)
2374 /// Populates the type context with all the implementations for the given
2375 /// trait if necessary.
2376 pub fn populate_implementations_for_trait_if_necessary(self, trait_id: DefId) {
2377 if trait_id.is_local() {
2381 // The type is not local, hence we are reading this out of
2382 // metadata and don't need to track edges.
2383 let _ignore = self.dep_graph.in_ignore();
2385 let def = self.trait_def(trait_id);
2386 if def.flags.get().intersects(TraitFlags::HAS_REMOTE_IMPLS) {
2390 debug!("populate_implementations_for_trait_if_necessary: searching for {:?}", def);
2392 for impl_def_id in self.sess.cstore.implementations_of_trait(Some(trait_id)) {
2393 let trait_ref = self.impl_trait_ref(impl_def_id).unwrap();
2395 // Record the trait->implementation mapping.
2396 let parent = self.sess.cstore.impl_parent(impl_def_id).unwrap_or(trait_id);
2397 def.record_remote_impl(self, impl_def_id, trait_ref, parent);
2400 def.flags.set(def.flags.get() | TraitFlags::HAS_REMOTE_IMPLS);
2403 /// Given the def_id of an impl, return the def_id of the trait it implements.
2404 /// If it implements no trait, return `None`.
2405 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2406 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2409 /// If the given def ID describes a method belonging to an impl, return the
2410 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2411 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2412 let item = if def_id.krate != LOCAL_CRATE {
2413 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2414 Some(self.associated_item(def_id))
2419 self.opt_associated_item(def_id)
2423 Some(trait_item) => {
2424 match trait_item.container {
2425 TraitContainer(_) => None,
2426 ImplContainer(def_id) => Some(def_id),
2433 /// If the given def ID describes an item belonging to a trait,
2434 /// return the ID of the trait that the trait item belongs to.
2435 /// Otherwise, return `None`.
2436 pub fn trait_of_item(self, def_id: DefId) -> Option<DefId> {
2437 if def_id.krate != LOCAL_CRATE {
2438 return self.sess.cstore.trait_of_item(def_id);
2440 self.opt_associated_item(def_id)
2441 .and_then(|associated_item| {
2442 match associated_item.container {
2443 TraitContainer(def_id) => Some(def_id),
2444 ImplContainer(_) => None
2449 /// Construct a parameter environment suitable for static contexts or other contexts where there
2450 /// are no free type/lifetime parameters in scope.
2451 pub fn empty_parameter_environment(self) -> ParameterEnvironment<'tcx> {
2452 ty::ParameterEnvironment {
2453 free_substs: self.intern_substs(&[]),
2454 caller_bounds: Slice::empty(),
2455 implicit_region_bound: None,
2456 free_id_outlive: None,
2457 is_copy_cache: RefCell::new(FxHashMap()),
2458 is_sized_cache: RefCell::new(FxHashMap()),
2459 is_freeze_cache: RefCell::new(FxHashMap()),
2463 /// Constructs and returns a substitution that can be applied to move from
2464 /// the "outer" view of a type or method to the "inner" view.
2465 /// In general, this means converting from bound parameters to
2466 /// free parameters. Since we currently represent bound/free type
2467 /// parameters in the same way, this only has an effect on regions.
2468 pub fn construct_free_substs(self,
2470 free_id_outlive: Option<CodeExtent<'gcx>>)
2471 -> &'gcx Substs<'gcx> {
2473 let substs = Substs::for_item(self.global_tcx(), def_id, |def, _| {
2474 // map bound 'a => free 'a
2475 self.global_tcx().mk_region(ReFree(FreeRegion {
2476 scope: free_id_outlive,
2477 bound_region: def.to_bound_region()
2481 self.global_tcx().mk_param_from_def(def)
2484 debug!("construct_parameter_environment: {:?}", substs);
2488 /// See `ParameterEnvironment` struct def'n for details.
2489 /// If you were using `free_id: NodeId`, you might try `self.region_maps().item_extent(free_id)`
2490 /// for the `free_id_outlive` parameter. (But note that this is not always quite right.)
2491 pub fn construct_parameter_environment(self,
2494 free_id_outlive: Option<CodeExtent<'gcx>>)
2495 -> ParameterEnvironment<'gcx>
2498 // Construct the free substs.
2501 let free_substs = self.construct_free_substs(def_id, free_id_outlive);
2504 // Compute the bounds on Self and the type parameters.
2507 let tcx = self.global_tcx();
2508 let generic_predicates = tcx.predicates_of(def_id);
2509 let bounds = generic_predicates.instantiate(tcx, free_substs);
2510 let bounds = tcx.liberate_late_bound_regions(free_id_outlive, &ty::Binder(bounds));
2511 let predicates = bounds.predicates;
2513 // Finally, we have to normalize the bounds in the environment, in
2514 // case they contain any associated type projections. This process
2515 // can yield errors if the put in illegal associated types, like
2516 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2517 // report these errors right here; this doesn't actually feel
2518 // right to me, because constructing the environment feels like a
2519 // kind of a "idempotent" action, but I'm not sure where would be
2520 // a better place. In practice, we construct environments for
2521 // every fn once during type checking, and we'll abort if there
2522 // are any errors at that point, so after type checking you can be
2523 // sure that this will succeed without errors anyway.
2526 let unnormalized_env = ty::ParameterEnvironment {
2527 free_substs: free_substs,
2528 implicit_region_bound: free_id_outlive.map(|f| tcx.mk_region(ty::ReScope(f))),
2529 caller_bounds: tcx.intern_predicates(&predicates),
2530 free_id_outlive: free_id_outlive,
2531 is_copy_cache: RefCell::new(FxHashMap()),
2532 is_sized_cache: RefCell::new(FxHashMap()),
2533 is_freeze_cache: RefCell::new(FxHashMap()),
2536 let body_id = free_id_outlive.map(|f| f.node_id())
2537 .unwrap_or(DUMMY_NODE_ID);
2538 let cause = traits::ObligationCause::misc(span, body_id);
2539 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
2542 pub fn node_scope_region(self, id: NodeId) -> Region<'tcx> {
2543 self.mk_region(ty::ReScope(self.node_extent(id)))
2546 pub fn visit_all_item_likes_in_krate<V,F>(self,
2549 where F: FnMut(DefId) -> DepNode<DefId>, V: ItemLikeVisitor<'gcx>
2551 dep_graph::visit_all_item_likes_in_krate(self.global_tcx(), dep_node_fn, visitor);
2554 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2555 /// with the name of the crate containing the impl.
2556 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2557 if impl_did.is_local() {
2558 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2559 Ok(self.hir.span(node_id))
2561 Err(self.sess.cstore.crate_name(impl_did.krate))
2566 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2567 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2568 F: FnOnce(&[hir::Freevar]) -> T,
2570 match self.freevars.borrow().get(&fid) {
2572 Some(d) => f(&d[..])
2577 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
2580 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2581 let parent_id = tcx.hir.get_parent(id);
2582 let parent_def_id = tcx.hir.local_def_id(parent_id);
2583 let parent_item = tcx.hir.expect_item(parent_id);
2584 match parent_item.node {
2585 hir::ItemImpl(.., ref impl_item_refs) => {
2586 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2587 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2589 debug_assert_eq!(assoc_item.def_id, def_id);
2594 hir::ItemTrait(.., ref trait_item_refs) => {
2595 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2596 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2599 debug_assert_eq!(assoc_item.def_id, def_id);
2607 span_bug!(parent_item.span,
2608 "unexpected parent of trait or impl item or item not found: {:?}",
2612 /// Calculates the Sized-constraint.
2614 /// In fact, there are only a few options for the types in the constraint:
2615 /// - an obviously-unsized type
2616 /// - a type parameter or projection whose Sizedness can't be known
2617 /// - a tuple of type parameters or projections, if there are multiple
2619 /// - a TyError, if a type contained itself. The representability
2620 /// check should catch this case.
2621 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2623 -> &'tcx [Ty<'tcx>] {
2624 let def = tcx.adt_def(def_id);
2626 let result = tcx.intern_type_list(&def.variants.iter().flat_map(|v| {
2629 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2630 }).collect::<Vec<_>>());
2632 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2637 /// Calculates the dtorck constraint for a type.
2638 fn adt_dtorck_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2640 -> DtorckConstraint<'tcx> {
2641 let def = tcx.adt_def(def_id);
2642 let span = tcx.def_span(def_id);
2643 debug!("dtorck_constraint: {:?}", def);
2645 if def.is_phantom_data() {
2646 let result = DtorckConstraint {
2649 tcx.mk_param_from_def(&tcx.generics_of(def_id).types[0])
2652 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2656 let mut result = def.all_fields()
2657 .map(|field| tcx.type_of(field.did))
2658 .map(|fty| tcx.dtorck_constraint_for_ty(span, fty, 0, fty))
2659 .collect::<Result<DtorckConstraint, ErrorReported>>()
2660 .unwrap_or(DtorckConstraint::empty());
2661 result.outlives.extend(tcx.destructor_constraints(def));
2664 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2669 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2672 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2673 let item = tcx.hir.expect_item(id);
2674 let vec: Vec<_> = match item.node {
2675 hir::ItemTrait(.., ref trait_item_refs) => {
2676 trait_item_refs.iter()
2677 .map(|trait_item_ref| trait_item_ref.id)
2678 .map(|id| tcx.hir.local_def_id(id.node_id))
2681 hir::ItemImpl(.., ref impl_item_refs) => {
2682 impl_item_refs.iter()
2683 .map(|impl_item_ref| impl_item_ref.id)
2684 .map(|id| tcx.hir.local_def_id(id.node_id))
2687 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2692 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
2693 tcx.hir.span_if_local(def_id).unwrap()
2696 pub fn provide(providers: &mut ty::maps::Providers) {
2697 *providers = ty::maps::Providers {
2699 associated_item_def_ids,
2700 adt_sized_constraint,
2701 adt_dtorck_constraint,
2707 pub fn provide_extern(providers: &mut ty::maps::Providers) {
2708 *providers = ty::maps::Providers {
2709 adt_sized_constraint,
2710 adt_dtorck_constraint,
2716 /// A map for the local crate mapping each type to a vector of its
2717 /// inherent impls. This is not meant to be used outside of coherence;
2718 /// rather, you should request the vector for a specific type via
2719 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2720 /// (constructing this map requires touching the entire crate).
2721 #[derive(Clone, Debug)]
2722 pub struct CrateInherentImpls {
2723 pub inherent_impls: DefIdMap<Rc<Vec<DefId>>>,
2726 /// A set of constraints that need to be satisfied in order for
2727 /// a type to be valid for destruction.
2728 #[derive(Clone, Debug)]
2729 pub struct DtorckConstraint<'tcx> {
2730 /// Types that are required to be alive in order for this
2731 /// type to be valid for destruction.
2732 pub outlives: Vec<ty::subst::Kind<'tcx>>,
2733 /// Types that could not be resolved: projections and params.
2734 pub dtorck_types: Vec<Ty<'tcx>>,
2737 impl<'tcx> FromIterator<DtorckConstraint<'tcx>> for DtorckConstraint<'tcx>
2739 fn from_iter<I: IntoIterator<Item=DtorckConstraint<'tcx>>>(iter: I) -> Self {
2740 let mut result = Self::empty();
2742 for constraint in iter {
2743 result.outlives.extend(constraint.outlives);
2744 result.dtorck_types.extend(constraint.dtorck_types);
2752 impl<'tcx> DtorckConstraint<'tcx> {
2753 fn empty() -> DtorckConstraint<'tcx> {
2756 dtorck_types: vec![]
2760 fn dedup<'a>(&mut self) {
2761 let mut outlives = FxHashSet();
2762 let mut dtorck_types = FxHashSet();
2764 self.outlives.retain(|&val| outlives.replace(val).is_none());
2765 self.dtorck_types.retain(|&val| dtorck_types.replace(val).is_none());
2769 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord)]
2770 pub struct SymbolName {
2771 // FIXME: we don't rely on interning or equality here - better have
2772 // this be a `&'tcx str`.
2773 pub name: InternedString
2776 impl Deref for SymbolName {
2779 fn deref(&self) -> &str { &self.name }
2782 impl fmt::Display for SymbolName {
2783 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2784 fmt::Display::fmt(&self.name, fmt)