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::resolve_lifetime::ObjectLifetimeDefault;
30 use ty::subst::{Subst, Substs};
31 use ty::util::IntTypeExt;
32 use ty::walk::TypeWalker;
33 use util::common::ErrorReported;
34 use util::nodemap::{NodeSet, DefIdMap, FxHashMap, FxHashSet};
36 use serialize::{self, Encodable, Encoder};
37 use std::cell::{Cell, RefCell};
38 use std::collections::BTreeMap;
41 use std::hash::{Hash, Hasher};
42 use std::iter::FromIterator;
46 use std::vec::IntoIter;
48 use syntax::ast::{self, DUMMY_NODE_ID, Name, NodeId};
50 use syntax::symbol::{Symbol, InternedString};
51 use syntax_pos::{DUMMY_SP, Span};
52 use rustc_const_math::ConstInt;
54 use rustc_data_structures::accumulate_vec::IntoIter as AccIntoIter;
55 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
57 use rustc_data_structures::transitive_relation::TransitiveRelation;
61 pub use self::sty::{Binder, DebruijnIndex};
62 pub use self::sty::{FnSig, PolyFnSig};
63 pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
64 pub use self::sty::{ClosureSubsts, TypeAndMut};
65 pub use self::sty::{TraitRef, TypeVariants, PolyTraitRef};
66 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
67 pub use self::sty::{ExistentialProjection, PolyExistentialProjection};
68 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
69 pub use self::sty::RegionKind;
70 pub use self::sty::Issue32330;
71 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid, SkolemizedRegionVid};
72 pub use self::sty::BoundRegion::*;
73 pub use self::sty::InferTy::*;
74 pub use self::sty::RegionKind::*;
75 pub use self::sty::TypeVariants::*;
77 pub use self::context::{TyCtxt, GlobalArenas, tls};
78 pub use self::context::{Lift, TypeckTables};
80 pub use self::instance::{Instance, InstanceDef};
82 pub use self::trait_def::{TraitDef, TraitFlags};
84 pub use self::maps::queries;
91 pub mod inhabitedness;
108 mod structural_impls;
113 /// The complete set of all analyses described in this module. This is
114 /// produced by the driver and fed to trans and later passes.
116 /// NB: These contents are being migrated into queries using the
117 /// *on-demand* infrastructure.
119 pub struct CrateAnalysis {
120 pub access_levels: Rc<AccessLevels>,
121 pub reachable: Rc<NodeSet>,
123 pub glob_map: Option<hir::GlobMap>,
127 pub struct Resolutions {
128 pub freevars: FreevarMap,
129 pub trait_map: TraitMap,
130 pub maybe_unused_trait_imports: NodeSet,
131 pub export_map: ExportMap,
134 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
135 pub enum AssociatedItemContainer {
136 TraitContainer(DefId),
137 ImplContainer(DefId),
140 impl AssociatedItemContainer {
141 pub fn id(&self) -> DefId {
143 TraitContainer(id) => id,
144 ImplContainer(id) => id,
149 /// The "header" of an impl is everything outside the body: a Self type, a trait
150 /// ref (in the case of a trait impl), and a set of predicates (from the
151 /// bounds/where clauses).
152 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
153 pub struct ImplHeader<'tcx> {
154 pub impl_def_id: DefId,
155 pub self_ty: Ty<'tcx>,
156 pub trait_ref: Option<TraitRef<'tcx>>,
157 pub predicates: Vec<Predicate<'tcx>>,
160 impl<'a, 'gcx, 'tcx> ImplHeader<'tcx> {
161 pub fn with_fresh_ty_vars(selcx: &mut traits::SelectionContext<'a, 'gcx, 'tcx>,
165 let tcx = selcx.tcx();
166 let impl_substs = selcx.infcx().fresh_substs_for_item(DUMMY_SP, impl_def_id);
168 let header = ImplHeader {
169 impl_def_id: impl_def_id,
170 self_ty: tcx.type_of(impl_def_id),
171 trait_ref: tcx.impl_trait_ref(impl_def_id),
172 predicates: tcx.predicates_of(impl_def_id).predicates
173 }.subst(tcx, impl_substs);
175 let traits::Normalized { value: mut header, obligations } =
176 traits::normalize(selcx, traits::ObligationCause::dummy(), &header);
178 header.predicates.extend(obligations.into_iter().map(|o| o.predicate));
183 #[derive(Copy, Clone, Debug)]
184 pub struct AssociatedItem {
187 pub kind: AssociatedKind,
189 pub defaultness: hir::Defaultness,
190 pub container: AssociatedItemContainer,
192 /// Whether this is a method with an explicit self
193 /// as its first argument, allowing method calls.
194 pub method_has_self_argument: bool,
197 #[derive(Copy, Clone, PartialEq, Eq, Debug, RustcEncodable, RustcDecodable)]
198 pub enum AssociatedKind {
204 impl AssociatedItem {
205 pub fn def(&self) -> Def {
207 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
208 AssociatedKind::Method => Def::Method(self.def_id),
209 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
213 /// Tests whether the associated item admits a non-trivial implementation
215 pub fn relevant_for_never<'tcx>(&self) -> bool {
217 AssociatedKind::Const => true,
218 AssociatedKind::Type => true,
219 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
220 AssociatedKind::Method => !self.method_has_self_argument,
225 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
226 pub enum Visibility {
227 /// Visible everywhere (including in other crates).
229 /// Visible only in the given crate-local module.
231 /// Not visible anywhere in the local crate. This is the visibility of private external items.
235 pub trait DefIdTree: Copy {
236 fn parent(self, id: DefId) -> Option<DefId>;
238 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
239 if descendant.krate != ancestor.krate {
243 while descendant != ancestor {
244 match self.parent(descendant) {
245 Some(parent) => descendant = parent,
246 None => return false,
253 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
254 fn parent(self, id: DefId) -> Option<DefId> {
255 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
260 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt) -> Self {
262 hir::Public => Visibility::Public,
263 hir::Visibility::Crate => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
264 hir::Visibility::Restricted { ref path, .. } => match path.def {
265 // If there is no resolution, `resolve` will have already reported an error, so
266 // assume that the visibility is public to avoid reporting more privacy errors.
267 Def::Err => Visibility::Public,
268 def => Visibility::Restricted(def.def_id()),
271 Visibility::Restricted(tcx.hir.local_def_id(tcx.hir.get_module_parent(id)))
276 /// Returns true if an item with this visibility is accessible from the given block.
277 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
278 let restriction = match self {
279 // Public items are visible everywhere.
280 Visibility::Public => return true,
281 // Private items from other crates are visible nowhere.
282 Visibility::Invisible => return false,
283 // Restricted items are visible in an arbitrary local module.
284 Visibility::Restricted(other) if other.krate != module.krate => return false,
285 Visibility::Restricted(module) => module,
288 tree.is_descendant_of(module, restriction)
291 /// Returns true if this visibility is at least as accessible as the given visibility
292 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
293 let vis_restriction = match vis {
294 Visibility::Public => return self == Visibility::Public,
295 Visibility::Invisible => return true,
296 Visibility::Restricted(module) => module,
299 self.is_accessible_from(vis_restriction, tree)
303 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
305 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
306 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
307 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
308 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
311 /// The crate variances map is computed during typeck and contains the
312 /// variance of every item in the local crate. You should not use it
313 /// directly, because to do so will make your pass dependent on the
314 /// HIR of every item in the local crate. Instead, use
315 /// `tcx.variances_of()` to get the variance for a *particular*
317 pub struct CrateVariancesMap {
318 /// This relation tracks the dependencies between the variance of
319 /// various items. In particular, if `a < b`, then the variance of
320 /// `a` depends on the sources of `b`.
321 pub dependencies: TransitiveRelation<DefId>,
323 /// For each item with generics, maps to a vector of the variance
324 /// of its generics. If an item has no generics, it will have no
326 pub variances: FxHashMap<DefId, Rc<Vec<ty::Variance>>>,
328 /// An empty vector, useful for cloning.
329 pub empty_variance: Rc<Vec<ty::Variance>>,
333 /// `a.xform(b)` combines the variance of a context with the
334 /// variance of a type with the following meaning. If we are in a
335 /// context with variance `a`, and we encounter a type argument in
336 /// a position with variance `b`, then `a.xform(b)` is the new
337 /// variance with which the argument appears.
343 /// Here, the "ambient" variance starts as covariant. `*mut T` is
344 /// invariant with respect to `T`, so the variance in which the
345 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
346 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
347 /// respect to its type argument `T`, and hence the variance of
348 /// the `i32` here is `Invariant.xform(Covariant)`, which results
349 /// (again) in `Invariant`.
353 /// fn(*const Vec<i32>, *mut Vec<i32)
355 /// The ambient variance is covariant. A `fn` type is
356 /// contravariant with respect to its parameters, so the variance
357 /// within which both pointer types appear is
358 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
359 /// T` is covariant with respect to `T`, so the variance within
360 /// which the first `Vec<i32>` appears is
361 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
362 /// is true for its `i32` argument. In the `*mut T` case, the
363 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
364 /// and hence the outermost type is `Invariant` with respect to
365 /// `Vec<i32>` (and its `i32` argument).
367 /// Source: Figure 1 of "Taming the Wildcards:
368 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
369 pub fn xform(self, v: ty::Variance) -> ty::Variance {
371 // Figure 1, column 1.
372 (ty::Covariant, ty::Covariant) => ty::Covariant,
373 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
374 (ty::Covariant, ty::Invariant) => ty::Invariant,
375 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
377 // Figure 1, column 2.
378 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
379 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
380 (ty::Contravariant, ty::Invariant) => ty::Invariant,
381 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
383 // Figure 1, column 3.
384 (ty::Invariant, _) => ty::Invariant,
386 // Figure 1, column 4.
387 (ty::Bivariant, _) => ty::Bivariant,
392 #[derive(Clone, Copy, Debug, RustcDecodable, RustcEncodable)]
393 pub struct MethodCallee<'tcx> {
394 /// Impl method ID, for inherent methods, or trait method ID, otherwise.
397 pub substs: &'tcx Substs<'tcx>
400 /// With method calls, we store some extra information in
401 /// side tables (i.e method_map). We use
402 /// MethodCall as a key to index into these tables instead of
403 /// just directly using the expression's NodeId. The reason
404 /// for this being that we may apply adjustments (coercions)
405 /// with the resulting expression also needing to use the
406 /// side tables. The problem with this is that we don't
407 /// assign a separate NodeId to this new expression
408 /// and so it would clash with the base expression if both
409 /// needed to add to the side tables. Thus to disambiguate
410 /// we also keep track of whether there's an adjustment in
412 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
413 pub struct MethodCall {
419 pub fn expr(id: NodeId) -> MethodCall {
426 pub fn autoderef(expr_id: NodeId, autoderef: u32) -> MethodCall {
429 autoderef: 1 + autoderef
434 // maps from an expression id that corresponds to a method call to the details
435 // of the method to be invoked
436 pub type MethodMap<'tcx> = FxHashMap<MethodCall, MethodCallee<'tcx>>;
438 // Contains information needed to resolve types and (in the future) look up
439 // the types of AST nodes.
440 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
441 pub struct CReaderCacheKey {
446 /// Describes the fragment-state associated with a NodeId.
448 /// Currently only unfragmented paths have entries in the table,
449 /// but longer-term this enum is expected to expand to also
450 /// include data for fragmented paths.
451 #[derive(Copy, Clone, Debug)]
452 pub enum FragmentInfo {
453 Moved { var: NodeId, move_expr: NodeId },
454 Assigned { var: NodeId, assign_expr: NodeId, assignee_id: NodeId },
457 // Flags that we track on types. These flags are propagated upwards
458 // through the type during type construction, so that we can quickly
459 // check whether the type has various kinds of types in it without
460 // recursing over the type itself.
462 flags TypeFlags: u32 {
463 const HAS_PARAMS = 1 << 0,
464 const HAS_SELF = 1 << 1,
465 const HAS_TY_INFER = 1 << 2,
466 const HAS_RE_INFER = 1 << 3,
467 const HAS_RE_SKOL = 1 << 4,
468 const HAS_RE_EARLY_BOUND = 1 << 5,
469 const HAS_FREE_REGIONS = 1 << 6,
470 const HAS_TY_ERR = 1 << 7,
471 const HAS_PROJECTION = 1 << 8,
472 const HAS_TY_CLOSURE = 1 << 9,
474 // true if there are "names" of types and regions and so forth
475 // that are local to a particular fn
476 const HAS_LOCAL_NAMES = 1 << 10,
478 // Present if the type belongs in a local type context.
479 // Only set for TyInfer other than Fresh.
480 const KEEP_IN_LOCAL_TCX = 1 << 11,
482 // Is there a projection that does not involve a bound region?
483 // Currently we can't normalize projections w/ bound regions.
484 const HAS_NORMALIZABLE_PROJECTION = 1 << 12,
486 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
487 TypeFlags::HAS_SELF.bits |
488 TypeFlags::HAS_RE_EARLY_BOUND.bits,
490 // Flags representing the nominal content of a type,
491 // computed by FlagsComputation. If you add a new nominal
492 // flag, it should be added here too.
493 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
494 TypeFlags::HAS_SELF.bits |
495 TypeFlags::HAS_TY_INFER.bits |
496 TypeFlags::HAS_RE_INFER.bits |
497 TypeFlags::HAS_RE_SKOL.bits |
498 TypeFlags::HAS_RE_EARLY_BOUND.bits |
499 TypeFlags::HAS_FREE_REGIONS.bits |
500 TypeFlags::HAS_TY_ERR.bits |
501 TypeFlags::HAS_PROJECTION.bits |
502 TypeFlags::HAS_TY_CLOSURE.bits |
503 TypeFlags::HAS_LOCAL_NAMES.bits |
504 TypeFlags::KEEP_IN_LOCAL_TCX.bits,
506 // Caches for type_is_sized, type_moves_by_default
507 const SIZEDNESS_CACHED = 1 << 16,
508 const IS_SIZED = 1 << 17,
509 const MOVENESS_CACHED = 1 << 18,
510 const MOVES_BY_DEFAULT = 1 << 19,
511 const FREEZENESS_CACHED = 1 << 20,
512 const IS_FREEZE = 1 << 21,
513 const NEEDS_DROP_CACHED = 1 << 22,
514 const NEEDS_DROP = 1 << 23,
518 pub struct TyS<'tcx> {
519 pub sty: TypeVariants<'tcx>,
520 pub flags: Cell<TypeFlags>,
522 // the maximal depth of any bound regions appearing in this type.
526 impl<'tcx> PartialEq for TyS<'tcx> {
528 fn eq(&self, other: &TyS<'tcx>) -> bool {
529 // (self as *const _) == (other as *const _)
530 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
533 impl<'tcx> Eq for TyS<'tcx> {}
535 impl<'tcx> Hash for TyS<'tcx> {
536 fn hash<H: Hasher>(&self, s: &mut H) {
537 (self as *const TyS).hash(s)
541 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for ty::TyS<'tcx> {
542 fn hash_stable<W: StableHasherResult>(&self,
543 hcx: &mut StableHashingContext<'a, 'tcx>,
544 hasher: &mut StableHasher<W>) {
548 // The other fields just provide fast access to information that is
549 // also contained in `sty`, so no need to hash them.
554 sty.hash_stable(hcx, hasher);
558 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
560 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
561 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
563 /// A wrapper for slices with the additional invariant
564 /// that the slice is interned and no other slice with
565 /// the same contents can exist in the same context.
566 /// This means we can use pointer + length for both
567 /// equality comparisons and hashing.
568 #[derive(Debug, RustcEncodable)]
569 pub struct Slice<T>([T]);
571 impl<T> PartialEq for Slice<T> {
573 fn eq(&self, other: &Slice<T>) -> bool {
574 (&self.0 as *const [T]) == (&other.0 as *const [T])
577 impl<T> Eq for Slice<T> {}
579 impl<T> Hash for Slice<T> {
580 fn hash<H: Hasher>(&self, s: &mut H) {
581 (self.as_ptr(), self.len()).hash(s)
585 impl<T> Deref for Slice<T> {
587 fn deref(&self) -> &[T] {
592 impl<'a, T> IntoIterator for &'a Slice<T> {
594 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
595 fn into_iter(self) -> Self::IntoIter {
600 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {}
603 pub fn empty<'a>() -> &'a Slice<T> {
605 mem::transmute(slice::from_raw_parts(0x1 as *const T, 0))
610 /// Upvars do not get their own node-id. Instead, we use the pair of
611 /// the original var id (that is, the root variable that is referenced
612 /// by the upvar) and the id of the closure expression.
613 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
616 pub closure_expr_id: NodeId,
619 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
620 pub enum BorrowKind {
621 /// Data must be immutable and is aliasable.
624 /// Data must be immutable but not aliasable. This kind of borrow
625 /// cannot currently be expressed by the user and is used only in
626 /// implicit closure bindings. It is needed when the closure
627 /// is borrowing or mutating a mutable referent, e.g.:
629 /// let x: &mut isize = ...;
630 /// let y = || *x += 5;
632 /// If we were to try to translate this closure into a more explicit
633 /// form, we'd encounter an error with the code as written:
635 /// struct Env { x: & &mut isize }
636 /// let x: &mut isize = ...;
637 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
638 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
640 /// This is then illegal because you cannot mutate a `&mut` found
641 /// in an aliasable location. To solve, you'd have to translate with
642 /// an `&mut` borrow:
644 /// struct Env { x: & &mut isize }
645 /// let x: &mut isize = ...;
646 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
647 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
649 /// Now the assignment to `**env.x` is legal, but creating a
650 /// mutable pointer to `x` is not because `x` is not mutable. We
651 /// could fix this by declaring `x` as `let mut x`. This is ok in
652 /// user code, if awkward, but extra weird for closures, since the
653 /// borrow is hidden.
655 /// So we introduce a "unique imm" borrow -- the referent is
656 /// immutable, but not aliasable. This solves the problem. For
657 /// simplicity, we don't give users the way to express this
658 /// borrow, it's just used when translating closures.
661 /// Data is mutable and not aliasable.
665 /// Information describing the capture of an upvar. This is computed
666 /// during `typeck`, specifically by `regionck`.
667 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
668 pub enum UpvarCapture<'tcx> {
669 /// Upvar is captured by value. This is always true when the
670 /// closure is labeled `move`, but can also be true in other cases
671 /// depending on inference.
674 /// Upvar is captured by reference.
675 ByRef(UpvarBorrow<'tcx>),
678 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
679 pub struct UpvarBorrow<'tcx> {
680 /// The kind of borrow: by-ref upvars have access to shared
681 /// immutable borrows, which are not part of the normal language
683 pub kind: BorrowKind,
685 /// Region of the resulting reference.
686 pub region: ty::Region<'tcx>,
689 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
691 #[derive(Copy, Clone)]
692 pub struct ClosureUpvar<'tcx> {
698 #[derive(Clone, Copy, PartialEq)]
699 pub enum IntVarValue {
701 UintType(ast::UintTy),
704 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
705 pub struct TypeParameterDef {
709 pub has_default: bool,
710 pub object_lifetime_default: ObjectLifetimeDefault,
712 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
713 /// on generic parameter `T`, asserts data behind the parameter
714 /// `T` won't be accessed during the parent type's `Drop` impl.
715 pub pure_wrt_drop: bool,
718 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
719 pub struct RegionParameterDef {
723 pub issue_32330: Option<ty::Issue32330>,
725 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
726 /// on generic parameter `'a`, asserts data of lifetime `'a`
727 /// won't be accessed during the parent type's `Drop` impl.
728 pub pure_wrt_drop: bool,
731 impl RegionParameterDef {
732 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
733 ty::EarlyBoundRegion {
739 pub fn to_bound_region(&self) -> ty::BoundRegion {
740 ty::BoundRegion::BrNamed(self.def_id, self.name)
744 /// Information about the formal type/lifetime parameters associated
745 /// with an item or method. Analogous to hir::Generics.
746 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
747 pub struct Generics {
748 pub parent: Option<DefId>,
749 pub parent_regions: u32,
750 pub parent_types: u32,
751 pub regions: Vec<RegionParameterDef>,
752 pub types: Vec<TypeParameterDef>,
754 /// Reverse map to each `TypeParameterDef`'s `index` field, from
755 /// `def_id.index` (`def_id.krate` is the same as the item's).
756 pub type_param_to_index: BTreeMap<DefIndex, u32>,
762 pub fn parent_count(&self) -> usize {
763 self.parent_regions as usize + self.parent_types as usize
766 pub fn own_count(&self) -> usize {
767 self.regions.len() + self.types.len()
770 pub fn count(&self) -> usize {
771 self.parent_count() + self.own_count()
774 pub fn region_param(&self, param: &EarlyBoundRegion) -> &RegionParameterDef {
775 assert_eq!(self.parent_count(), 0);
776 &self.regions[param.index as usize - self.has_self as usize]
779 pub fn type_param(&self, param: &ParamTy) -> &TypeParameterDef {
780 assert_eq!(self.parent_count(), 0);
781 &self.types[param.idx as usize - self.has_self as usize - self.regions.len()]
785 /// Bounds on generics.
786 #[derive(Clone, Default)]
787 pub struct GenericPredicates<'tcx> {
788 pub parent: Option<DefId>,
789 pub predicates: Vec<Predicate<'tcx>>,
792 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
793 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
795 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
796 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
797 -> InstantiatedPredicates<'tcx> {
798 let mut instantiated = InstantiatedPredicates::empty();
799 self.instantiate_into(tcx, &mut instantiated, substs);
802 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
803 -> InstantiatedPredicates<'tcx> {
804 InstantiatedPredicates {
805 predicates: self.predicates.subst(tcx, substs)
809 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
810 instantiated: &mut InstantiatedPredicates<'tcx>,
811 substs: &Substs<'tcx>) {
812 if let Some(def_id) = self.parent {
813 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
815 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
818 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
819 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
820 -> InstantiatedPredicates<'tcx>
822 assert_eq!(self.parent, None);
823 InstantiatedPredicates {
824 predicates: self.predicates.iter().map(|pred| {
825 pred.subst_supertrait(tcx, poly_trait_ref)
831 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
832 pub enum Predicate<'tcx> {
833 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
834 /// the `Self` type of the trait reference and `A`, `B`, and `C`
835 /// would be the type parameters.
836 Trait(PolyTraitPredicate<'tcx>),
838 /// where `T1 == T2`.
839 Equate(PolyEquatePredicate<'tcx>),
842 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
845 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
847 /// where <T as TraitRef>::Name == X, approximately.
848 /// See `ProjectionPredicate` struct for details.
849 Projection(PolyProjectionPredicate<'tcx>),
852 WellFormed(Ty<'tcx>),
854 /// trait must be object-safe
857 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
858 /// for some substitutions `...` and T being a closure type.
859 /// Satisfied (or refuted) once we know the closure's kind.
860 ClosureKind(DefId, ClosureKind),
863 Subtype(PolySubtypePredicate<'tcx>),
866 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
867 /// Performs a substitution suitable for going from a
868 /// poly-trait-ref to supertraits that must hold if that
869 /// poly-trait-ref holds. This is slightly different from a normal
870 /// substitution in terms of what happens with bound regions. See
871 /// lengthy comment below for details.
872 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
873 trait_ref: &ty::PolyTraitRef<'tcx>)
874 -> ty::Predicate<'tcx>
876 // The interaction between HRTB and supertraits is not entirely
877 // obvious. Let me walk you (and myself) through an example.
879 // Let's start with an easy case. Consider two traits:
881 // trait Foo<'a> : Bar<'a,'a> { }
882 // trait Bar<'b,'c> { }
884 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
885 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
886 // knew that `Foo<'x>` (for any 'x) then we also know that
887 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
888 // normal substitution.
890 // In terms of why this is sound, the idea is that whenever there
891 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
892 // holds. So if there is an impl of `T:Foo<'a>` that applies to
893 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
896 // Another example to be careful of is this:
898 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
899 // trait Bar1<'b,'c> { }
901 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
902 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
903 // reason is similar to the previous example: any impl of
904 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
905 // basically we would want to collapse the bound lifetimes from
906 // the input (`trait_ref`) and the supertraits.
908 // To achieve this in practice is fairly straightforward. Let's
909 // consider the more complicated scenario:
911 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
912 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
913 // where both `'x` and `'b` would have a DB index of 1.
914 // The substitution from the input trait-ref is therefore going to be
915 // `'a => 'x` (where `'x` has a DB index of 1).
916 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
917 // early-bound parameter and `'b' is a late-bound parameter with a
919 // - If we replace `'a` with `'x` from the input, it too will have
920 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
921 // just as we wanted.
923 // There is only one catch. If we just apply the substitution `'a
924 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
925 // adjust the DB index because we substituting into a binder (it
926 // tries to be so smart...) resulting in `for<'x> for<'b>
927 // Bar1<'x,'b>` (we have no syntax for this, so use your
928 // imagination). Basically the 'x will have DB index of 2 and 'b
929 // will have DB index of 1. Not quite what we want. So we apply
930 // the substitution to the *contents* of the trait reference,
931 // rather than the trait reference itself (put another way, the
932 // substitution code expects equal binding levels in the values
933 // from the substitution and the value being substituted into, and
934 // this trick achieves that).
936 let substs = &trait_ref.0.substs;
938 Predicate::Trait(ty::Binder(ref data)) =>
939 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
940 Predicate::Equate(ty::Binder(ref data)) =>
941 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
942 Predicate::Subtype(ty::Binder(ref data)) =>
943 Predicate::Subtype(ty::Binder(data.subst(tcx, substs))),
944 Predicate::RegionOutlives(ty::Binder(ref data)) =>
945 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
946 Predicate::TypeOutlives(ty::Binder(ref data)) =>
947 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
948 Predicate::Projection(ty::Binder(ref data)) =>
949 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
950 Predicate::WellFormed(data) =>
951 Predicate::WellFormed(data.subst(tcx, substs)),
952 Predicate::ObjectSafe(trait_def_id) =>
953 Predicate::ObjectSafe(trait_def_id),
954 Predicate::ClosureKind(closure_def_id, kind) =>
955 Predicate::ClosureKind(closure_def_id, kind),
960 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
961 pub struct TraitPredicate<'tcx> {
962 pub trait_ref: TraitRef<'tcx>
964 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
966 impl<'tcx> TraitPredicate<'tcx> {
967 pub fn def_id(&self) -> DefId {
968 self.trait_ref.def_id
971 /// Creates the dep-node for selecting/evaluating this trait reference.
972 fn dep_node(&self) -> DepNode<DefId> {
973 // Extact the trait-def and first def-id from inputs. See the
974 // docs for `DepNode::TraitSelect` for more information.
975 let trait_def_id = self.def_id();
978 .flat_map(|t| t.walk())
979 .filter_map(|t| match t.sty {
980 ty::TyAdt(adt_def, _) => Some(adt_def.did),
984 .unwrap_or(trait_def_id);
985 DepNode::TraitSelect {
986 trait_def_id: trait_def_id,
987 input_def_id: input_def_id
991 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
992 self.trait_ref.input_types()
995 pub fn self_ty(&self) -> Ty<'tcx> {
996 self.trait_ref.self_ty()
1000 impl<'tcx> PolyTraitPredicate<'tcx> {
1001 pub fn def_id(&self) -> DefId {
1002 // ok to skip binder since trait def-id does not care about regions
1006 pub fn dep_node(&self) -> DepNode<DefId> {
1007 // ok to skip binder since depnode does not care about regions
1012 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1013 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
1014 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
1016 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1017 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
1018 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1019 pub type PolyRegionOutlivesPredicate<'tcx> = PolyOutlivesPredicate<ty::Region<'tcx>,
1021 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
1023 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1024 pub struct SubtypePredicate<'tcx> {
1025 pub a_is_expected: bool,
1029 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1031 /// This kind of predicate has no *direct* correspondent in the
1032 /// syntax, but it roughly corresponds to the syntactic forms:
1034 /// 1. `T : TraitRef<..., Item=Type>`
1035 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1037 /// In particular, form #1 is "desugared" to the combination of a
1038 /// normal trait predicate (`T : TraitRef<...>`) and one of these
1039 /// predicates. Form #2 is a broader form in that it also permits
1040 /// equality between arbitrary types. Processing an instance of Form
1041 /// #2 eventually yields one of these `ProjectionPredicate`
1042 /// instances to normalize the LHS.
1043 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1044 pub struct ProjectionPredicate<'tcx> {
1045 pub projection_ty: ProjectionTy<'tcx>,
1049 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1051 impl<'tcx> PolyProjectionPredicate<'tcx> {
1052 pub fn item_name(&self) -> Name {
1053 self.0.projection_ty.item_name // safe to skip the binder to access a name
1057 pub trait ToPolyTraitRef<'tcx> {
1058 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1061 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1062 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1063 assert!(!self.has_escaping_regions());
1064 ty::Binder(self.clone())
1068 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1069 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1070 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1074 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
1075 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1076 // Note: unlike with TraitRef::to_poly_trait_ref(),
1077 // self.0.trait_ref is permitted to have escaping regions.
1078 // This is because here `self` has a `Binder` and so does our
1079 // return value, so we are preserving the number of binding
1081 ty::Binder(self.0.projection_ty.trait_ref)
1085 pub trait ToPredicate<'tcx> {
1086 fn to_predicate(&self) -> Predicate<'tcx>;
1089 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1090 fn to_predicate(&self) -> Predicate<'tcx> {
1091 // we're about to add a binder, so let's check that we don't
1092 // accidentally capture anything, or else that might be some
1093 // weird debruijn accounting.
1094 assert!(!self.has_escaping_regions());
1096 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
1097 trait_ref: self.clone()
1102 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1103 fn to_predicate(&self) -> Predicate<'tcx> {
1104 ty::Predicate::Trait(self.to_poly_trait_predicate())
1108 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
1109 fn to_predicate(&self) -> Predicate<'tcx> {
1110 Predicate::Equate(self.clone())
1114 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1115 fn to_predicate(&self) -> Predicate<'tcx> {
1116 Predicate::RegionOutlives(self.clone())
1120 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1121 fn to_predicate(&self) -> Predicate<'tcx> {
1122 Predicate::TypeOutlives(self.clone())
1126 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1127 fn to_predicate(&self) -> Predicate<'tcx> {
1128 Predicate::Projection(self.clone())
1132 impl<'tcx> Predicate<'tcx> {
1133 /// Iterates over the types in this predicate. Note that in all
1134 /// cases this is skipping over a binder, so late-bound regions
1135 /// with depth 0 are bound by the predicate.
1136 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1137 let vec: Vec<_> = match *self {
1138 ty::Predicate::Trait(ref data) => {
1139 data.skip_binder().input_types().collect()
1141 ty::Predicate::Equate(ty::Binder(ref data)) => {
1142 vec![data.0, data.1]
1144 ty::Predicate::Subtype(ty::Binder(SubtypePredicate { a, b, a_is_expected: _ })) => {
1147 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
1150 ty::Predicate::RegionOutlives(..) => {
1153 ty::Predicate::Projection(ref data) => {
1154 let trait_inputs = data.0.projection_ty.trait_ref.input_types();
1155 trait_inputs.chain(Some(data.0.ty)).collect()
1157 ty::Predicate::WellFormed(data) => {
1160 ty::Predicate::ObjectSafe(_trait_def_id) => {
1163 ty::Predicate::ClosureKind(_closure_def_id, _kind) => {
1168 // The only reason to collect into a vector here is that I was
1169 // too lazy to make the full (somewhat complicated) iterator
1170 // type that would be needed here. But I wanted this fn to
1171 // return an iterator conceptually, rather than a `Vec`, so as
1172 // to be closer to `Ty::walk`.
1176 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1178 Predicate::Trait(ref t) => {
1179 Some(t.to_poly_trait_ref())
1181 Predicate::Projection(..) |
1182 Predicate::Equate(..) |
1183 Predicate::Subtype(..) |
1184 Predicate::RegionOutlives(..) |
1185 Predicate::WellFormed(..) |
1186 Predicate::ObjectSafe(..) |
1187 Predicate::ClosureKind(..) |
1188 Predicate::TypeOutlives(..) => {
1195 /// Represents the bounds declared on a particular set of type
1196 /// parameters. Should eventually be generalized into a flag list of
1197 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1198 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1199 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1200 /// the `GenericPredicates` are expressed in terms of the bound type
1201 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1202 /// represented a set of bounds for some particular instantiation,
1203 /// meaning that the generic parameters have been substituted with
1208 /// struct Foo<T,U:Bar<T>> { ... }
1210 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1211 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1212 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1213 /// [usize:Bar<isize>]]`.
1215 pub struct InstantiatedPredicates<'tcx> {
1216 pub predicates: Vec<Predicate<'tcx>>,
1219 impl<'tcx> InstantiatedPredicates<'tcx> {
1220 pub fn empty() -> InstantiatedPredicates<'tcx> {
1221 InstantiatedPredicates { predicates: vec![] }
1224 pub fn is_empty(&self) -> bool {
1225 self.predicates.is_empty()
1229 /// When type checking, we use the `ParameterEnvironment` to track
1230 /// details about the type/lifetime parameters that are in scope.
1231 /// It primarily stores the bounds information.
1233 /// Note: This information might seem to be redundant with the data in
1234 /// `tcx.ty_param_defs`, but it is not. That table contains the
1235 /// parameter definitions from an "outside" perspective, but this
1236 /// struct will contain the bounds for a parameter as seen from inside
1237 /// the function body. Currently the only real distinction is that
1238 /// bound lifetime parameters are replaced with free ones, but in the
1239 /// future I hope to refine the representation of types so as to make
1240 /// more distinctions clearer.
1242 pub struct ParameterEnvironment<'tcx> {
1243 /// See `construct_free_substs` for details.
1244 pub free_substs: &'tcx Substs<'tcx>,
1246 /// Obligations that the caller must satisfy. This is basically
1247 /// the set of bounds on the in-scope type parameters, translated
1248 /// into Obligations, and elaborated and normalized.
1249 pub caller_bounds: &'tcx [ty::Predicate<'tcx>],
1251 /// A cache for `moves_by_default`.
1252 pub is_copy_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1254 /// A cache for `type_is_sized`
1255 pub is_sized_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1257 /// A cache for `type_is_freeze`
1258 pub is_freeze_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1261 impl<'a, 'tcx> ParameterEnvironment<'tcx> {
1262 pub fn with_caller_bounds(&self,
1263 caller_bounds: &'tcx [ty::Predicate<'tcx>])
1264 -> ParameterEnvironment<'tcx>
1266 ParameterEnvironment {
1267 free_substs: self.free_substs,
1268 caller_bounds: caller_bounds,
1269 is_copy_cache: RefCell::new(FxHashMap()),
1270 is_sized_cache: RefCell::new(FxHashMap()),
1271 is_freeze_cache: RefCell::new(FxHashMap()),
1276 #[derive(Copy, Clone, Debug)]
1277 pub struct Destructor {
1278 /// The def-id of the destructor method
1283 flags AdtFlags: u32 {
1284 const NO_ADT_FLAGS = 0,
1285 const IS_ENUM = 1 << 0,
1286 const IS_PHANTOM_DATA = 1 << 1,
1287 const IS_FUNDAMENTAL = 1 << 2,
1288 const IS_UNION = 1 << 3,
1289 const IS_BOX = 1 << 4,
1294 pub struct VariantDef {
1295 /// The variant's DefId. If this is a tuple-like struct,
1296 /// this is the DefId of the struct's ctor.
1298 pub name: Name, // struct's name if this is a struct
1299 pub discr: VariantDiscr,
1300 pub fields: Vec<FieldDef>,
1301 pub ctor_kind: CtorKind,
1304 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1305 pub enum VariantDiscr {
1306 /// Explicit value for this variant, i.e. `X = 123`.
1307 /// The `DefId` corresponds to the embedded constant.
1310 /// The previous variant's discriminant plus one.
1311 /// For efficiency reasons, the distance from the
1312 /// last `Explicit` discriminant is being stored,
1313 /// or `0` for the first variant, if it has none.
1318 pub struct FieldDef {
1321 pub vis: Visibility,
1324 /// The definition of an abstract data type - a struct or enum.
1326 /// These are all interned (by intern_adt_def) into the adt_defs
1330 pub variants: Vec<VariantDef>,
1332 pub repr: ReprOptions,
1335 impl PartialEq for AdtDef {
1336 // AdtDef are always interned and this is part of TyS equality
1338 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1341 impl Eq for AdtDef {}
1343 impl Hash for AdtDef {
1345 fn hash<H: Hasher>(&self, s: &mut H) {
1346 (self as *const AdtDef).hash(s)
1350 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1351 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1356 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1359 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for AdtDef {
1360 fn hash_stable<W: StableHasherResult>(&self,
1361 hcx: &mut StableHashingContext<'a, 'tcx>,
1362 hasher: &mut StableHasher<W>) {
1370 did.hash_stable(hcx, hasher);
1371 variants.hash_stable(hcx, hasher);
1372 flags.hash_stable(hcx, hasher);
1373 repr.hash_stable(hcx, hasher);
1377 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1378 pub enum AdtKind { Struct, Union, Enum }
1381 #[derive(RustcEncodable, RustcDecodable, Default)]
1382 flags ReprFlags: u8 {
1383 const IS_C = 1 << 0,
1384 const IS_PACKED = 1 << 1,
1385 const IS_SIMD = 1 << 2,
1386 // Internal only for now. If true, don't reorder fields.
1387 const IS_LINEAR = 1 << 3,
1389 // Any of these flags being set prevent field reordering optimisation.
1390 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1391 ReprFlags::IS_PACKED.bits |
1392 ReprFlags::IS_SIMD.bits |
1393 ReprFlags::IS_LINEAR.bits,
1397 impl_stable_hash_for!(struct ReprFlags {
1403 /// Represents the repr options provided by the user,
1404 #[derive(Copy, Clone, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1405 pub struct ReprOptions {
1406 pub int: Option<attr::IntType>,
1408 pub flags: ReprFlags,
1411 impl_stable_hash_for!(struct ReprOptions {
1418 pub fn new(tcx: TyCtxt, did: DefId) -> ReprOptions {
1419 let mut flags = ReprFlags::empty();
1420 let mut size = None;
1421 let mut max_align = 0;
1422 for attr in tcx.get_attrs(did).iter() {
1423 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1424 flags.insert(match r {
1425 attr::ReprExtern => ReprFlags::IS_C,
1426 attr::ReprPacked => ReprFlags::IS_PACKED,
1427 attr::ReprSimd => ReprFlags::IS_SIMD,
1428 attr::ReprInt(i) => {
1432 attr::ReprAlign(align) => {
1433 max_align = cmp::max(align, max_align);
1440 // FIXME(eddyb) This is deprecated and should be removed.
1441 if tcx.has_attr(did, "simd") {
1442 flags.insert(ReprFlags::IS_SIMD);
1445 // This is here instead of layout because the choice must make it into metadata.
1446 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1447 flags.insert(ReprFlags::IS_LINEAR);
1449 ReprOptions { int: size, align: max_align, flags: flags }
1453 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1455 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1457 pub fn packed(&self) -> bool { self.flags.contains(ReprFlags::IS_PACKED) }
1459 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1461 pub fn discr_type(&self) -> attr::IntType {
1462 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Is))
1465 /// Returns true if this `#[repr()]` should inhabit "smart enum
1466 /// layout" optimizations, such as representing `Foo<&T>` as a
1468 pub fn inhibit_enum_layout_opt(&self) -> bool {
1469 self.c() || self.int.is_some()
1473 impl<'a, 'gcx, 'tcx> AdtDef {
1477 variants: Vec<VariantDef>,
1478 repr: ReprOptions) -> Self {
1479 let mut flags = AdtFlags::NO_ADT_FLAGS;
1480 let attrs = tcx.get_attrs(did);
1481 if attr::contains_name(&attrs, "fundamental") {
1482 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1484 if Some(did) == tcx.lang_items.phantom_data() {
1485 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1487 if Some(did) == tcx.lang_items.owned_box() {
1488 flags = flags | AdtFlags::IS_BOX;
1491 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
1492 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
1493 AdtKind::Struct => {}
1504 pub fn is_struct(&self) -> bool {
1505 !self.is_union() && !self.is_enum()
1509 pub fn is_union(&self) -> bool {
1510 self.flags.intersects(AdtFlags::IS_UNION)
1514 pub fn is_enum(&self) -> bool {
1515 self.flags.intersects(AdtFlags::IS_ENUM)
1518 /// Returns the kind of the ADT - Struct or Enum.
1520 pub fn adt_kind(&self) -> AdtKind {
1523 } else if self.is_union() {
1530 pub fn descr(&self) -> &'static str {
1531 match self.adt_kind() {
1532 AdtKind::Struct => "struct",
1533 AdtKind::Union => "union",
1534 AdtKind::Enum => "enum",
1538 pub fn variant_descr(&self) -> &'static str {
1539 match self.adt_kind() {
1540 AdtKind::Struct => "struct",
1541 AdtKind::Union => "union",
1542 AdtKind::Enum => "variant",
1546 /// Returns whether this type is #[fundamental] for the purposes
1547 /// of coherence checking.
1549 pub fn is_fundamental(&self) -> bool {
1550 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
1553 /// Returns true if this is PhantomData<T>.
1555 pub fn is_phantom_data(&self) -> bool {
1556 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
1559 /// Returns true if this is Box<T>.
1561 pub fn is_box(&self) -> bool {
1562 self.flags.intersects(AdtFlags::IS_BOX)
1565 /// Returns whether this type has a destructor.
1566 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
1567 self.destructor(tcx).is_some()
1570 /// Asserts this is a struct and returns the struct's unique
1572 pub fn struct_variant(&self) -> &VariantDef {
1573 assert!(!self.is_enum());
1578 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
1579 tcx.predicates_of(self.did)
1582 /// Returns an iterator over all fields contained
1585 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
1586 self.variants.iter().flat_map(|v| v.fields.iter())
1590 pub fn is_univariant(&self) -> bool {
1591 self.variants.len() == 1
1594 pub fn is_payloadfree(&self) -> bool {
1595 !self.variants.is_empty() &&
1596 self.variants.iter().all(|v| v.fields.is_empty())
1599 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
1602 .find(|v| v.did == vid)
1603 .expect("variant_with_id: unknown variant")
1606 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1609 .position(|v| v.did == vid)
1610 .expect("variant_index_with_id: unknown variant")
1613 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
1615 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
1616 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
1617 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.struct_variant(),
1618 _ => bug!("unexpected def {:?} in variant_of_def", def)
1623 pub fn discriminants(&'a self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1624 -> impl Iterator<Item=ConstInt> + 'a {
1625 let repr_type = self.repr.discr_type();
1626 let initial = repr_type.initial_discriminant(tcx.global_tcx());
1627 let mut prev_discr = None::<ConstInt>;
1628 self.variants.iter().map(move |v| {
1629 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr());
1630 if let VariantDiscr::Explicit(expr_did) = v.discr {
1631 let substs = Substs::empty();
1632 match tcx.const_eval((expr_did, substs)) {
1633 Ok(ConstVal::Integral(v)) => {
1637 if !expr_did.is_local() {
1638 span_bug!(tcx.def_span(expr_did),
1639 "variant discriminant evaluation succeeded \
1640 in its crate but failed locally: {:?}", err);
1645 prev_discr = Some(discr);
1651 /// Compute the discriminant value used by a specific variant.
1652 /// Unlike `discriminants`, this is (amortized) constant-time,
1653 /// only doing at most one query for evaluating an explicit
1654 /// discriminant (the last one before the requested variant),
1655 /// assuming there are no constant-evaluation errors there.
1656 pub fn discriminant_for_variant(&self,
1657 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1658 variant_index: usize)
1660 let repr_type = self.repr.discr_type();
1661 let mut explicit_value = repr_type.initial_discriminant(tcx.global_tcx());
1662 let mut explicit_index = variant_index;
1664 match self.variants[explicit_index].discr {
1665 ty::VariantDiscr::Relative(0) => break,
1666 ty::VariantDiscr::Relative(distance) => {
1667 explicit_index -= distance;
1669 ty::VariantDiscr::Explicit(expr_did) => {
1670 let substs = Substs::empty();
1671 match tcx.const_eval((expr_did, substs)) {
1672 Ok(ConstVal::Integral(v)) => {
1677 if !expr_did.is_local() {
1678 span_bug!(tcx.def_span(expr_did),
1679 "variant discriminant evaluation succeeded \
1680 in its crate but failed locally: {:?}", err);
1682 if explicit_index == 0 {
1685 explicit_index -= 1;
1691 let discr = explicit_value.to_u128_unchecked()
1692 .wrapping_add((variant_index - explicit_index) as u128);
1694 attr::UnsignedInt(ty) => {
1695 ConstInt::new_unsigned_truncating(discr, ty,
1696 tcx.sess.target.uint_type)
1698 attr::SignedInt(ty) => {
1699 ConstInt::new_signed_truncating(discr as i128, ty,
1700 tcx.sess.target.int_type)
1705 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
1706 tcx.adt_destructor(self.did)
1709 /// Returns a list of types such that `Self: Sized` if and only
1710 /// if that type is Sized, or `TyErr` if this type is recursive.
1712 /// Oddly enough, checking that the sized-constraint is Sized is
1713 /// actually more expressive than checking all members:
1714 /// the Sized trait is inductive, so an associated type that references
1715 /// Self would prevent its containing ADT from being Sized.
1717 /// Due to normalization being eager, this applies even if
1718 /// the associated type is behind a pointer, e.g. issue #31299.
1719 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
1720 match queries::adt_sized_constraint::try_get(tcx, DUMMY_SP, self.did) {
1723 debug!("adt_sized_constraint: {:?} is recursive", self);
1724 // This should be reported as an error by `check_representable`.
1726 // Consider the type as Sized in the meanwhile to avoid
1728 tcx.intern_type_list(&[tcx.types.err])
1733 fn sized_constraint_for_ty(&self,
1734 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1737 let result = match ty.sty {
1738 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
1739 TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
1740 TyArray(..) | TyClosure(..) | TyNever => {
1744 TyStr | TyDynamic(..) | TySlice(_) | TyError => {
1745 // these are never sized - return the target type
1749 TyTuple(ref tys, _) => {
1752 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
1756 TyAdt(adt, substs) => {
1758 let adt_tys = adt.sized_constraint(tcx);
1759 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
1762 .map(|ty| ty.subst(tcx, substs))
1763 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
1767 TyProjection(..) | TyAnon(..) => {
1768 // must calculate explicitly.
1769 // FIXME: consider special-casing always-Sized projections
1774 // perf hack: if there is a `T: Sized` bound, then
1775 // we know that `T` is Sized and do not need to check
1778 let sized_trait = match tcx.lang_items.sized_trait() {
1780 _ => return vec![ty]
1782 let sized_predicate = Binder(TraitRef {
1783 def_id: sized_trait,
1784 substs: tcx.mk_substs_trait(ty, &[])
1786 let predicates = tcx.predicates_of(self.did).predicates;
1787 if predicates.into_iter().any(|p| p == sized_predicate) {
1795 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
1799 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
1804 impl<'a, 'gcx, 'tcx> VariantDef {
1806 pub fn find_field_named(&self,
1808 -> Option<&FieldDef> {
1809 self.fields.iter().find(|f| f.name == name)
1813 pub fn index_of_field_named(&self,
1816 self.fields.iter().position(|f| f.name == name)
1820 pub fn field_named(&self, name: ast::Name) -> &FieldDef {
1821 self.find_field_named(name).unwrap()
1825 impl<'a, 'gcx, 'tcx> FieldDef {
1826 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1827 tcx.type_of(self.did).subst(tcx, subst)
1831 /// Records the substitutions used to translate the polytype for an
1832 /// item into the monotype of an item reference.
1833 #[derive(Clone, RustcEncodable, RustcDecodable)]
1834 pub struct ItemSubsts<'tcx> {
1835 pub substs: &'tcx Substs<'tcx>,
1838 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1839 pub enum ClosureKind {
1840 // Warning: Ordering is significant here! The ordering is chosen
1841 // because the trait Fn is a subtrait of FnMut and so in turn, and
1842 // hence we order it so that Fn < FnMut < FnOnce.
1848 impl<'a, 'tcx> ClosureKind {
1849 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
1851 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
1852 ClosureKind::FnMut => {
1853 tcx.require_lang_item(FnMutTraitLangItem)
1855 ClosureKind::FnOnce => {
1856 tcx.require_lang_item(FnOnceTraitLangItem)
1861 /// True if this a type that impls this closure kind
1862 /// must also implement `other`.
1863 pub fn extends(self, other: ty::ClosureKind) -> bool {
1864 match (self, other) {
1865 (ClosureKind::Fn, ClosureKind::Fn) => true,
1866 (ClosureKind::Fn, ClosureKind::FnMut) => true,
1867 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
1868 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
1869 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
1870 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
1876 impl<'tcx> TyS<'tcx> {
1877 /// Iterator that walks `self` and any types reachable from
1878 /// `self`, in depth-first order. Note that just walks the types
1879 /// that appear in `self`, it does not descend into the fields of
1880 /// structs or variants. For example:
1883 /// isize => { isize }
1884 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
1885 /// [isize] => { [isize], isize }
1887 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
1888 TypeWalker::new(self)
1891 /// Iterator that walks the immediate children of `self`. Hence
1892 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
1893 /// (but not `i32`, like `walk`).
1894 pub fn walk_shallow(&'tcx self) -> AccIntoIter<walk::TypeWalkerArray<'tcx>> {
1895 walk::walk_shallow(self)
1898 /// Walks `ty` and any types appearing within `ty`, invoking the
1899 /// callback `f` on each type. If the callback returns false, then the
1900 /// children of the current type are ignored.
1902 /// Note: prefer `ty.walk()` where possible.
1903 pub fn maybe_walk<F>(&'tcx self, mut f: F)
1904 where F : FnMut(Ty<'tcx>) -> bool
1906 let mut walker = self.walk();
1907 while let Some(ty) = walker.next() {
1909 walker.skip_current_subtree();
1915 impl<'tcx> ItemSubsts<'tcx> {
1916 pub fn is_noop(&self) -> bool {
1917 self.substs.is_noop()
1921 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1922 pub enum LvaluePreference {
1927 impl LvaluePreference {
1928 pub fn from_mutbl(m: hir::Mutability) -> Self {
1930 hir::MutMutable => PreferMutLvalue,
1931 hir::MutImmutable => NoPreference,
1937 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
1939 hir::MutMutable => MutBorrow,
1940 hir::MutImmutable => ImmBorrow,
1944 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
1945 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
1946 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
1948 pub fn to_mutbl_lossy(self) -> hir::Mutability {
1950 MutBorrow => hir::MutMutable,
1951 ImmBorrow => hir::MutImmutable,
1953 // We have no type corresponding to a unique imm borrow, so
1954 // use `&mut`. It gives all the capabilities of an `&uniq`
1955 // and hence is a safe "over approximation".
1956 UniqueImmBorrow => hir::MutMutable,
1960 pub fn to_user_str(&self) -> &'static str {
1962 MutBorrow => "mutable",
1963 ImmBorrow => "immutable",
1964 UniqueImmBorrow => "uniquely immutable",
1969 #[derive(Debug, Clone)]
1970 pub enum Attributes<'gcx> {
1971 Owned(Rc<[ast::Attribute]>),
1972 Borrowed(&'gcx [ast::Attribute])
1975 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
1976 type Target = [ast::Attribute];
1978 fn deref(&self) -> &[ast::Attribute] {
1980 &Attributes::Owned(ref data) => &data,
1981 &Attributes::Borrowed(data) => data
1986 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
1987 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
1988 self.typeck_tables_of(self.hir.body_owner_def_id(body))
1991 /// Returns an iterator of the def-ids for all body-owners in this
1992 /// crate. If you would prefer to iterate over the bodies
1993 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
1994 pub fn body_owners(self) -> impl Iterator<Item = DefId> + 'a {
1998 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
2001 pub fn expr_span(self, id: NodeId) -> Span {
2002 match self.hir.find(id) {
2003 Some(hir_map::NodeExpr(e)) => {
2007 bug!("Node id {} is not an expr: {:?}", id, f);
2010 bug!("Node id {} is not present in the node map", id);
2015 pub fn local_var_name_str(self, id: NodeId) -> InternedString {
2016 match self.hir.find(id) {
2017 Some(hir_map::NodeLocal(pat)) => {
2019 hir::PatKind::Binding(_, _, ref path1, _) => path1.node.as_str(),
2021 bug!("Variable id {} maps to {:?}, not local", id, pat);
2025 r => bug!("Variable id {} maps to {:?}, not local", id, r),
2029 pub fn expr_is_lval(self, expr: &hir::Expr) -> bool {
2031 hir::ExprPath(hir::QPath::Resolved(_, ref path)) => {
2033 Def::Local(..) | Def::Upvar(..) | Def::Static(..) | Def::Err => true,
2038 hir::ExprType(ref e, _) => {
2039 self.expr_is_lval(e)
2042 hir::ExprUnary(hir::UnDeref, _) |
2043 hir::ExprField(..) |
2044 hir::ExprTupField(..) |
2045 hir::ExprIndex(..) => {
2049 // Partially qualified paths in expressions can only legally
2050 // refer to associated items which are always rvalues.
2051 hir::ExprPath(hir::QPath::TypeRelative(..)) |
2054 hir::ExprMethodCall(..) |
2055 hir::ExprStruct(..) |
2058 hir::ExprMatch(..) |
2059 hir::ExprClosure(..) |
2060 hir::ExprBlock(..) |
2061 hir::ExprRepeat(..) |
2062 hir::ExprArray(..) |
2063 hir::ExprBreak(..) |
2064 hir::ExprAgain(..) |
2066 hir::ExprWhile(..) |
2068 hir::ExprAssign(..) |
2069 hir::ExprInlineAsm(..) |
2070 hir::ExprAssignOp(..) |
2072 hir::ExprUnary(..) |
2074 hir::ExprAddrOf(..) |
2075 hir::ExprBinary(..) |
2076 hir::ExprCast(..) => {
2082 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2083 self.associated_items(id)
2084 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2088 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2089 self.associated_items(did).any(|item| {
2090 item.relevant_for_never()
2094 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2095 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2096 match self.hir.get(node_id) {
2097 hir_map::NodeTraitItem(_) | hir_map::NodeImplItem(_) => true,
2101 match self.describe_def(def_id).expect("no def for def-id") {
2102 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2107 if is_associated_item {
2108 Some(self.associated_item(def_id))
2114 fn associated_item_from_trait_item_ref(self,
2115 parent_def_id: DefId,
2116 parent_vis: &hir::Visibility,
2117 trait_item_ref: &hir::TraitItemRef)
2119 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2120 let (kind, has_self) = match trait_item_ref.kind {
2121 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2122 hir::AssociatedItemKind::Method { has_self } => {
2123 (ty::AssociatedKind::Method, has_self)
2125 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2129 name: trait_item_ref.name,
2131 // Visibility of trait items is inherited from their traits.
2132 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2133 defaultness: trait_item_ref.defaultness,
2135 container: TraitContainer(parent_def_id),
2136 method_has_self_argument: has_self
2140 fn associated_item_from_impl_item_ref(self,
2141 parent_def_id: DefId,
2142 impl_item_ref: &hir::ImplItemRef)
2144 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2145 let (kind, has_self) = match impl_item_ref.kind {
2146 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2147 hir::AssociatedItemKind::Method { has_self } => {
2148 (ty::AssociatedKind::Method, has_self)
2150 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2153 ty::AssociatedItem {
2154 name: impl_item_ref.name,
2156 // Visibility of trait impl items doesn't matter.
2157 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2158 defaultness: impl_item_ref.defaultness,
2160 container: ImplContainer(parent_def_id),
2161 method_has_self_argument: has_self
2165 #[inline] // FIXME(#35870) Avoid closures being unexported due to impl Trait.
2166 pub fn associated_items(self, def_id: DefId)
2167 -> impl Iterator<Item = ty::AssociatedItem> + 'a {
2168 let def_ids = self.associated_item_def_ids(def_id);
2169 (0..def_ids.len()).map(move |i| self.associated_item(def_ids[i]))
2172 /// Returns true if the impls are the same polarity and are implementing
2173 /// a trait which contains no items
2174 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2175 if !self.sess.features.borrow().overlapping_marker_traits {
2178 let trait1_is_empty = self.impl_trait_ref(def_id1)
2179 .map_or(false, |trait_ref| {
2180 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2182 let trait2_is_empty = self.impl_trait_ref(def_id2)
2183 .map_or(false, |trait_ref| {
2184 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2186 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2191 // Returns `ty::VariantDef` if `def` refers to a struct,
2192 // or variant or their constructors, panics otherwise.
2193 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2195 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2196 let enum_did = self.parent_def_id(did).unwrap();
2197 self.adt_def(enum_did).variant_with_id(did)
2199 Def::Struct(did) | Def::Union(did) => {
2200 self.adt_def(did).struct_variant()
2202 Def::StructCtor(ctor_did, ..) => {
2203 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2204 self.adt_def(did).struct_variant()
2206 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2210 pub fn def_key(self, id: DefId) -> hir_map::DefKey {
2212 self.hir.def_key(id)
2214 self.sess.cstore.def_key(id)
2218 /// Convert a `DefId` into its fully expanded `DefPath` (every
2219 /// `DefId` is really just an interned def-path).
2221 /// Note that if `id` is not local to this crate, the result will
2222 /// be a non-local `DefPath`.
2223 pub fn def_path(self, id: DefId) -> hir_map::DefPath {
2225 self.hir.def_path(id)
2227 self.sess.cstore.def_path(id)
2232 pub fn def_path_hash(self, def_id: DefId) -> u64 {
2233 if def_id.is_local() {
2234 self.hir.definitions().def_path_hash(def_id.index)
2236 self.sess.cstore.def_path_hash(def_id)
2240 pub fn vis_is_accessible_from(self, vis: Visibility, block: NodeId) -> bool {
2241 vis.is_accessible_from(self.hir.local_def_id(self.hir.get_module_parent(block)), self)
2244 pub fn item_name(self, id: DefId) -> ast::Name {
2245 if let Some(id) = self.hir.as_local_node_id(id) {
2247 } else if id.index == CRATE_DEF_INDEX {
2248 self.sess.cstore.original_crate_name(id.krate)
2250 let def_key = self.sess.cstore.def_key(id);
2251 // The name of a StructCtor is that of its struct parent.
2252 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2253 self.item_name(DefId {
2255 index: def_key.parent.unwrap()
2258 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2259 bug!("item_name: no name for {:?}", self.def_path(id));
2265 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2266 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2270 ty::InstanceDef::Item(did) => {
2271 self.optimized_mir(did)
2273 ty::InstanceDef::Intrinsic(..) |
2274 ty::InstanceDef::FnPtrShim(..) |
2275 ty::InstanceDef::Virtual(..) |
2276 ty::InstanceDef::ClosureOnceShim { .. } |
2277 ty::InstanceDef::DropGlue(..) => {
2278 self.mir_shims(instance)
2283 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2284 /// Returns None if there is no MIR for the DefId
2285 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2286 if self.is_mir_available(did) {
2287 Some(self.optimized_mir(did))
2293 /// Get the attributes of a definition.
2294 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2295 if let Some(id) = self.hir.as_local_node_id(did) {
2296 Attributes::Borrowed(self.hir.attrs(id))
2298 Attributes::Owned(self.item_attrs(did))
2302 /// Determine whether an item is annotated with an attribute
2303 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2304 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2307 pub fn trait_has_default_impl(self, trait_def_id: DefId) -> bool {
2308 let def = self.trait_def(trait_def_id);
2309 def.flags.get().intersects(TraitFlags::HAS_DEFAULT_IMPL)
2312 /// Populates the type context with all the implementations for the given
2313 /// trait if necessary.
2314 pub fn populate_implementations_for_trait_if_necessary(self, trait_id: DefId) {
2315 if trait_id.is_local() {
2319 // The type is not local, hence we are reading this out of
2320 // metadata and don't need to track edges.
2321 let _ignore = self.dep_graph.in_ignore();
2323 let def = self.trait_def(trait_id);
2324 if def.flags.get().intersects(TraitFlags::HAS_REMOTE_IMPLS) {
2328 debug!("populate_implementations_for_trait_if_necessary: searching for {:?}", def);
2330 for impl_def_id in self.sess.cstore.implementations_of_trait(Some(trait_id)) {
2331 let trait_ref = self.impl_trait_ref(impl_def_id).unwrap();
2333 // Record the trait->implementation mapping.
2334 let parent = self.impl_parent(impl_def_id).unwrap_or(trait_id);
2335 def.record_remote_impl(self, impl_def_id, trait_ref, parent);
2338 def.flags.set(def.flags.get() | TraitFlags::HAS_REMOTE_IMPLS);
2341 /// Given the def_id of an impl, return the def_id of the trait it implements.
2342 /// If it implements no trait, return `None`.
2343 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2344 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2347 /// If the given def ID describes a method belonging to an impl, return the
2348 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2349 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2350 let item = if def_id.krate != LOCAL_CRATE {
2351 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2352 Some(self.associated_item(def_id))
2357 self.opt_associated_item(def_id)
2361 Some(trait_item) => {
2362 match trait_item.container {
2363 TraitContainer(_) => None,
2364 ImplContainer(def_id) => Some(def_id),
2371 /// Construct a parameter environment suitable for static contexts or other contexts where there
2372 /// are no free type/lifetime parameters in scope.
2373 pub fn empty_parameter_environment(self) -> ParameterEnvironment<'tcx> {
2374 ty::ParameterEnvironment {
2375 free_substs: self.intern_substs(&[]),
2376 caller_bounds: Slice::empty(),
2377 is_copy_cache: RefCell::new(FxHashMap()),
2378 is_sized_cache: RefCell::new(FxHashMap()),
2379 is_freeze_cache: RefCell::new(FxHashMap()),
2383 /// Constructs and returns a substitution that can be applied to move from
2384 /// the "outer" view of a type or method to the "inner" view.
2385 /// In general, this means converting from bound parameters to
2386 /// free parameters. Since we currently represent bound/free type
2387 /// parameters in the same way, this only has an effect on regions.
2388 pub fn construct_free_substs(self, def_id: DefId) -> &'gcx Substs<'gcx> {
2390 let substs = Substs::for_item(self.global_tcx(), def_id, |def, _| {
2391 // map bound 'a => free 'a
2392 self.global_tcx().mk_region(ReFree(FreeRegion {
2394 bound_region: def.to_bound_region()
2398 self.global_tcx().mk_param_from_def(def)
2401 debug!("parameter_environment: {:?}", substs);
2405 /// See `ParameterEnvironment` struct def'n for details.
2406 pub fn parameter_environment(self, def_id: DefId) -> ParameterEnvironment<'gcx> {
2408 // Construct the free substs.
2411 let free_substs = self.construct_free_substs(def_id);
2414 // Compute the bounds on Self and the type parameters.
2417 let tcx = self.global_tcx();
2418 let generic_predicates = tcx.predicates_of(def_id);
2419 let bounds = generic_predicates.instantiate(tcx, free_substs);
2420 let bounds = tcx.liberate_late_bound_regions(def_id, &ty::Binder(bounds));
2421 let predicates = bounds.predicates;
2423 // Finally, we have to normalize the bounds in the environment, in
2424 // case they contain any associated type projections. This process
2425 // can yield errors if the put in illegal associated types, like
2426 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2427 // report these errors right here; this doesn't actually feel
2428 // right to me, because constructing the environment feels like a
2429 // kind of a "idempotent" action, but I'm not sure where would be
2430 // a better place. In practice, we construct environments for
2431 // every fn once during type checking, and we'll abort if there
2432 // are any errors at that point, so after type checking you can be
2433 // sure that this will succeed without errors anyway.
2436 let unnormalized_env = ty::ParameterEnvironment {
2438 caller_bounds: tcx.intern_predicates(&predicates),
2439 is_copy_cache: RefCell::new(FxHashMap()),
2440 is_sized_cache: RefCell::new(FxHashMap()),
2441 is_freeze_cache: RefCell::new(FxHashMap()),
2444 let body_id = self.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
2445 self.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_id)
2447 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
2448 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
2451 pub fn node_scope_region(self, id: NodeId) -> Region<'tcx> {
2452 self.mk_region(ty::ReScope(self.node_extent(id)))
2455 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2456 /// with the name of the crate containing the impl.
2457 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2458 if impl_did.is_local() {
2459 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2460 Ok(self.hir.span(node_id))
2462 Err(self.sess.cstore.crate_name(impl_did.krate))
2467 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2468 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2469 F: FnOnce(&[hir::Freevar]) -> T,
2471 match self.freevars.borrow().get(&fid) {
2473 Some(d) => f(&d[..])
2478 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
2481 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2482 let parent_id = tcx.hir.get_parent(id);
2483 let parent_def_id = tcx.hir.local_def_id(parent_id);
2484 let parent_item = tcx.hir.expect_item(parent_id);
2485 match parent_item.node {
2486 hir::ItemImpl(.., ref impl_item_refs) => {
2487 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2488 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2490 debug_assert_eq!(assoc_item.def_id, def_id);
2495 hir::ItemTrait(.., ref trait_item_refs) => {
2496 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2497 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2500 debug_assert_eq!(assoc_item.def_id, def_id);
2508 span_bug!(parent_item.span,
2509 "unexpected parent of trait or impl item or item not found: {:?}",
2513 /// Calculates the Sized-constraint.
2515 /// In fact, there are only a few options for the types in the constraint:
2516 /// - an obviously-unsized type
2517 /// - a type parameter or projection whose Sizedness can't be known
2518 /// - a tuple of type parameters or projections, if there are multiple
2520 /// - a TyError, if a type contained itself. The representability
2521 /// check should catch this case.
2522 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2524 -> &'tcx [Ty<'tcx>] {
2525 let def = tcx.adt_def(def_id);
2527 let result = tcx.intern_type_list(&def.variants.iter().flat_map(|v| {
2530 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2531 }).collect::<Vec<_>>());
2533 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2538 /// Calculates the dtorck constraint for a type.
2539 fn adt_dtorck_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2541 -> DtorckConstraint<'tcx> {
2542 let def = tcx.adt_def(def_id);
2543 let span = tcx.def_span(def_id);
2544 debug!("dtorck_constraint: {:?}", def);
2546 if def.is_phantom_data() {
2547 let result = DtorckConstraint {
2550 tcx.mk_param_from_def(&tcx.generics_of(def_id).types[0])
2553 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2557 let mut result = def.all_fields()
2558 .map(|field| tcx.type_of(field.did))
2559 .map(|fty| tcx.dtorck_constraint_for_ty(span, fty, 0, fty))
2560 .collect::<Result<DtorckConstraint, ErrorReported>>()
2561 .unwrap_or(DtorckConstraint::empty());
2562 result.outlives.extend(tcx.destructor_constraints(def));
2565 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2570 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2573 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2574 let item = tcx.hir.expect_item(id);
2575 let vec: Vec<_> = match item.node {
2576 hir::ItemTrait(.., ref trait_item_refs) => {
2577 trait_item_refs.iter()
2578 .map(|trait_item_ref| trait_item_ref.id)
2579 .map(|id| tcx.hir.local_def_id(id.node_id))
2582 hir::ItemImpl(.., ref impl_item_refs) => {
2583 impl_item_refs.iter()
2584 .map(|impl_item_ref| impl_item_ref.id)
2585 .map(|id| tcx.hir.local_def_id(id.node_id))
2588 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2593 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
2594 tcx.hir.span_if_local(def_id).unwrap()
2597 /// If the given def ID describes an item belonging to a trait,
2598 /// return the ID of the trait that the trait item belongs to.
2599 /// Otherwise, return `None`.
2600 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
2601 tcx.opt_associated_item(def_id)
2602 .and_then(|associated_item| {
2603 match associated_item.container {
2604 TraitContainer(def_id) => Some(def_id),
2605 ImplContainer(_) => None
2611 pub fn provide(providers: &mut ty::maps::Providers) {
2612 *providers = ty::maps::Providers {
2614 associated_item_def_ids,
2615 adt_sized_constraint,
2616 adt_dtorck_constraint,
2623 pub fn provide_extern(providers: &mut ty::maps::Providers) {
2624 *providers = ty::maps::Providers {
2625 adt_sized_constraint,
2626 adt_dtorck_constraint,
2632 /// A map for the local crate mapping each type to a vector of its
2633 /// inherent impls. This is not meant to be used outside of coherence;
2634 /// rather, you should request the vector for a specific type via
2635 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2636 /// (constructing this map requires touching the entire crate).
2637 #[derive(Clone, Debug)]
2638 pub struct CrateInherentImpls {
2639 pub inherent_impls: DefIdMap<Rc<Vec<DefId>>>,
2642 /// A set of constraints that need to be satisfied in order for
2643 /// a type to be valid for destruction.
2644 #[derive(Clone, Debug)]
2645 pub struct DtorckConstraint<'tcx> {
2646 /// Types that are required to be alive in order for this
2647 /// type to be valid for destruction.
2648 pub outlives: Vec<ty::subst::Kind<'tcx>>,
2649 /// Types that could not be resolved: projections and params.
2650 pub dtorck_types: Vec<Ty<'tcx>>,
2653 impl<'tcx> FromIterator<DtorckConstraint<'tcx>> for DtorckConstraint<'tcx>
2655 fn from_iter<I: IntoIterator<Item=DtorckConstraint<'tcx>>>(iter: I) -> Self {
2656 let mut result = Self::empty();
2658 for constraint in iter {
2659 result.outlives.extend(constraint.outlives);
2660 result.dtorck_types.extend(constraint.dtorck_types);
2668 impl<'tcx> DtorckConstraint<'tcx> {
2669 fn empty() -> DtorckConstraint<'tcx> {
2672 dtorck_types: vec![]
2676 fn dedup<'a>(&mut self) {
2677 let mut outlives = FxHashSet();
2678 let mut dtorck_types = FxHashSet();
2680 self.outlives.retain(|&val| outlives.replace(val).is_none());
2681 self.dtorck_types.retain(|&val| dtorck_types.replace(val).is_none());
2685 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord)]
2686 pub struct SymbolName {
2687 // FIXME: we don't rely on interning or equality here - better have
2688 // this be a `&'tcx str`.
2689 pub name: InternedString
2692 impl Deref for SymbolName {
2695 fn deref(&self) -> &str { &self.name }
2698 impl fmt::Display for SymbolName {
2699 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2700 fmt::Display::fmt(&self.name, fmt)