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::{self, 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;
27 use middle::region::CodeExtent;
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::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;
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,
508 pub struct TyS<'tcx> {
509 pub sty: TypeVariants<'tcx>,
510 pub flags: TypeFlags,
512 // the maximal depth of any bound regions appearing in this type.
516 impl<'tcx> PartialEq for TyS<'tcx> {
518 fn eq(&self, other: &TyS<'tcx>) -> bool {
519 // (self as *const _) == (other as *const _)
520 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
523 impl<'tcx> Eq for TyS<'tcx> {}
525 impl<'tcx> Hash for TyS<'tcx> {
526 fn hash<H: Hasher>(&self, s: &mut H) {
527 (self as *const TyS).hash(s)
531 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for ty::TyS<'tcx> {
532 fn hash_stable<W: StableHasherResult>(&self,
533 hcx: &mut StableHashingContext<'a, 'tcx>,
534 hasher: &mut StableHasher<W>) {
538 // The other fields just provide fast access to information that is
539 // also contained in `sty`, so no need to hash them.
544 sty.hash_stable(hcx, hasher);
548 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
550 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
551 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
553 /// A wrapper for slices with the additional invariant
554 /// that the slice is interned and no other slice with
555 /// the same contents can exist in the same context.
556 /// This means we can use pointer + length for both
557 /// equality comparisons and hashing.
558 #[derive(Debug, RustcEncodable)]
559 pub struct Slice<T>([T]);
561 impl<T> PartialEq for Slice<T> {
563 fn eq(&self, other: &Slice<T>) -> bool {
564 (&self.0 as *const [T]) == (&other.0 as *const [T])
567 impl<T> Eq for Slice<T> {}
569 impl<T> Hash for Slice<T> {
570 fn hash<H: Hasher>(&self, s: &mut H) {
571 (self.as_ptr(), self.len()).hash(s)
575 impl<T> Deref for Slice<T> {
577 fn deref(&self) -> &[T] {
582 impl<'a, T> IntoIterator for &'a Slice<T> {
584 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
585 fn into_iter(self) -> Self::IntoIter {
590 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {}
593 pub fn empty<'a>() -> &'a Slice<T> {
595 mem::transmute(slice::from_raw_parts(0x1 as *const T, 0))
600 /// Upvars do not get their own node-id. Instead, we use the pair of
601 /// the original var id (that is, the root variable that is referenced
602 /// by the upvar) and the id of the closure expression.
603 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
606 pub closure_expr_id: NodeId,
609 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
610 pub enum BorrowKind {
611 /// Data must be immutable and is aliasable.
614 /// Data must be immutable but not aliasable. This kind of borrow
615 /// cannot currently be expressed by the user and is used only in
616 /// implicit closure bindings. It is needed when the closure
617 /// is borrowing or mutating a mutable referent, e.g.:
619 /// let x: &mut isize = ...;
620 /// let y = || *x += 5;
622 /// If we were to try to translate this closure into a more explicit
623 /// form, we'd encounter an error with the code as written:
625 /// struct Env { x: & &mut isize }
626 /// let x: &mut isize = ...;
627 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
628 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
630 /// This is then illegal because you cannot mutate a `&mut` found
631 /// in an aliasable location. To solve, you'd have to translate with
632 /// an `&mut` borrow:
634 /// struct Env { x: & &mut isize }
635 /// let x: &mut isize = ...;
636 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
637 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
639 /// Now the assignment to `**env.x` is legal, but creating a
640 /// mutable pointer to `x` is not because `x` is not mutable. We
641 /// could fix this by declaring `x` as `let mut x`. This is ok in
642 /// user code, if awkward, but extra weird for closures, since the
643 /// borrow is hidden.
645 /// So we introduce a "unique imm" borrow -- the referent is
646 /// immutable, but not aliasable. This solves the problem. For
647 /// simplicity, we don't give users the way to express this
648 /// borrow, it's just used when translating closures.
651 /// Data is mutable and not aliasable.
655 /// Information describing the capture of an upvar. This is computed
656 /// during `typeck`, specifically by `regionck`.
657 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
658 pub enum UpvarCapture<'tcx> {
659 /// Upvar is captured by value. This is always true when the
660 /// closure is labeled `move`, but can also be true in other cases
661 /// depending on inference.
664 /// Upvar is captured by reference.
665 ByRef(UpvarBorrow<'tcx>),
668 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
669 pub struct UpvarBorrow<'tcx> {
670 /// The kind of borrow: by-ref upvars have access to shared
671 /// immutable borrows, which are not part of the normal language
673 pub kind: BorrowKind,
675 /// Region of the resulting reference.
676 pub region: ty::Region<'tcx>,
679 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
681 #[derive(Copy, Clone)]
682 pub struct ClosureUpvar<'tcx> {
688 #[derive(Clone, Copy, PartialEq)]
689 pub enum IntVarValue {
691 UintType(ast::UintTy),
694 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
695 pub struct TypeParameterDef {
699 pub has_default: bool,
700 pub object_lifetime_default: ObjectLifetimeDefault,
702 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
703 /// on generic parameter `T`, asserts data behind the parameter
704 /// `T` won't be accessed during the parent type's `Drop` impl.
705 pub pure_wrt_drop: bool,
708 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
709 pub struct RegionParameterDef {
713 pub issue_32330: Option<ty::Issue32330>,
715 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
716 /// on generic parameter `'a`, asserts data of lifetime `'a`
717 /// won't be accessed during the parent type's `Drop` impl.
718 pub pure_wrt_drop: bool,
721 impl RegionParameterDef {
722 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
723 ty::EarlyBoundRegion {
730 pub fn to_bound_region(&self) -> ty::BoundRegion {
731 self.to_early_bound_region_data().to_bound_region()
735 impl ty::EarlyBoundRegion {
736 pub fn to_bound_region(&self) -> ty::BoundRegion {
737 ty::BoundRegion::BrNamed(self.def_id, self.name)
741 /// Information about the formal type/lifetime parameters associated
742 /// with an item or method. Analogous to hir::Generics.
743 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
744 pub struct Generics {
745 pub parent: Option<DefId>,
746 pub parent_regions: u32,
747 pub parent_types: u32,
748 pub regions: Vec<RegionParameterDef>,
749 pub types: Vec<TypeParameterDef>,
751 /// Reverse map to each `TypeParameterDef`'s `index` field, from
752 /// `def_id.index` (`def_id.krate` is the same as the item's).
753 pub type_param_to_index: BTreeMap<DefIndex, u32>,
759 pub fn parent_count(&self) -> usize {
760 self.parent_regions as usize + self.parent_types as usize
763 pub fn own_count(&self) -> usize {
764 self.regions.len() + self.types.len()
767 pub fn count(&self) -> usize {
768 self.parent_count() + self.own_count()
771 pub fn region_param(&self, param: &EarlyBoundRegion) -> &RegionParameterDef {
772 assert_eq!(self.parent_count(), 0);
773 &self.regions[param.index as usize - self.has_self as usize]
776 pub fn type_param(&self, param: &ParamTy) -> &TypeParameterDef {
777 assert_eq!(self.parent_count(), 0);
778 &self.types[param.idx as usize - self.has_self as usize - self.regions.len()]
782 /// Bounds on generics.
783 #[derive(Clone, Default)]
784 pub struct GenericPredicates<'tcx> {
785 pub parent: Option<DefId>,
786 pub predicates: Vec<Predicate<'tcx>>,
789 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
790 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
792 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
793 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
794 -> InstantiatedPredicates<'tcx> {
795 let mut instantiated = InstantiatedPredicates::empty();
796 self.instantiate_into(tcx, &mut instantiated, substs);
799 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
800 -> InstantiatedPredicates<'tcx> {
801 InstantiatedPredicates {
802 predicates: self.predicates.subst(tcx, substs)
806 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
807 instantiated: &mut InstantiatedPredicates<'tcx>,
808 substs: &Substs<'tcx>) {
809 if let Some(def_id) = self.parent {
810 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
812 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
815 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
816 -> InstantiatedPredicates<'tcx> {
817 let mut instantiated = InstantiatedPredicates::empty();
818 self.instantiate_identity_into(tcx, &mut instantiated);
822 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
823 instantiated: &mut InstantiatedPredicates<'tcx>) {
824 if let Some(def_id) = self.parent {
825 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
827 instantiated.predicates.extend(&self.predicates)
830 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
831 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
832 -> InstantiatedPredicates<'tcx>
834 assert_eq!(self.parent, None);
835 InstantiatedPredicates {
836 predicates: self.predicates.iter().map(|pred| {
837 pred.subst_supertrait(tcx, poly_trait_ref)
843 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
844 pub enum Predicate<'tcx> {
845 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
846 /// the `Self` type of the trait reference and `A`, `B`, and `C`
847 /// would be the type parameters.
848 Trait(PolyTraitPredicate<'tcx>),
850 /// where `T1 == T2`.
851 Equate(PolyEquatePredicate<'tcx>),
854 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
857 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
859 /// where <T as TraitRef>::Name == X, approximately.
860 /// See `ProjectionPredicate` struct for details.
861 Projection(PolyProjectionPredicate<'tcx>),
864 WellFormed(Ty<'tcx>),
866 /// trait must be object-safe
869 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
870 /// for some substitutions `...` and T being a closure type.
871 /// Satisfied (or refuted) once we know the closure's kind.
872 ClosureKind(DefId, ClosureKind),
875 Subtype(PolySubtypePredicate<'tcx>),
878 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
879 /// Performs a substitution suitable for going from a
880 /// poly-trait-ref to supertraits that must hold if that
881 /// poly-trait-ref holds. This is slightly different from a normal
882 /// substitution in terms of what happens with bound regions. See
883 /// lengthy comment below for details.
884 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
885 trait_ref: &ty::PolyTraitRef<'tcx>)
886 -> ty::Predicate<'tcx>
888 // The interaction between HRTB and supertraits is not entirely
889 // obvious. Let me walk you (and myself) through an example.
891 // Let's start with an easy case. Consider two traits:
893 // trait Foo<'a> : Bar<'a,'a> { }
894 // trait Bar<'b,'c> { }
896 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
897 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
898 // knew that `Foo<'x>` (for any 'x) then we also know that
899 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
900 // normal substitution.
902 // In terms of why this is sound, the idea is that whenever there
903 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
904 // holds. So if there is an impl of `T:Foo<'a>` that applies to
905 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
908 // Another example to be careful of is this:
910 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
911 // trait Bar1<'b,'c> { }
913 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
914 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
915 // reason is similar to the previous example: any impl of
916 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
917 // basically we would want to collapse the bound lifetimes from
918 // the input (`trait_ref`) and the supertraits.
920 // To achieve this in practice is fairly straightforward. Let's
921 // consider the more complicated scenario:
923 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
924 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
925 // where both `'x` and `'b` would have a DB index of 1.
926 // The substitution from the input trait-ref is therefore going to be
927 // `'a => 'x` (where `'x` has a DB index of 1).
928 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
929 // early-bound parameter and `'b' is a late-bound parameter with a
931 // - If we replace `'a` with `'x` from the input, it too will have
932 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
933 // just as we wanted.
935 // There is only one catch. If we just apply the substitution `'a
936 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
937 // adjust the DB index because we substituting into a binder (it
938 // tries to be so smart...) resulting in `for<'x> for<'b>
939 // Bar1<'x,'b>` (we have no syntax for this, so use your
940 // imagination). Basically the 'x will have DB index of 2 and 'b
941 // will have DB index of 1. Not quite what we want. So we apply
942 // the substitution to the *contents* of the trait reference,
943 // rather than the trait reference itself (put another way, the
944 // substitution code expects equal binding levels in the values
945 // from the substitution and the value being substituted into, and
946 // this trick achieves that).
948 let substs = &trait_ref.0.substs;
950 Predicate::Trait(ty::Binder(ref data)) =>
951 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
952 Predicate::Equate(ty::Binder(ref data)) =>
953 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
954 Predicate::Subtype(ty::Binder(ref data)) =>
955 Predicate::Subtype(ty::Binder(data.subst(tcx, substs))),
956 Predicate::RegionOutlives(ty::Binder(ref data)) =>
957 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
958 Predicate::TypeOutlives(ty::Binder(ref data)) =>
959 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
960 Predicate::Projection(ty::Binder(ref data)) =>
961 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
962 Predicate::WellFormed(data) =>
963 Predicate::WellFormed(data.subst(tcx, substs)),
964 Predicate::ObjectSafe(trait_def_id) =>
965 Predicate::ObjectSafe(trait_def_id),
966 Predicate::ClosureKind(closure_def_id, kind) =>
967 Predicate::ClosureKind(closure_def_id, kind),
972 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
973 pub struct TraitPredicate<'tcx> {
974 pub trait_ref: TraitRef<'tcx>
976 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
978 impl<'tcx> TraitPredicate<'tcx> {
979 pub fn def_id(&self) -> DefId {
980 self.trait_ref.def_id
983 /// Creates the dep-node for selecting/evaluating this trait reference.
984 fn dep_node(&self) -> DepNode<DefId> {
985 // Extact the trait-def and first def-id from inputs. See the
986 // docs for `DepNode::TraitSelect` for more information.
987 let trait_def_id = self.def_id();
990 .flat_map(|t| t.walk())
991 .filter_map(|t| match t.sty {
992 ty::TyAdt(adt_def, _) => Some(adt_def.did),
996 .unwrap_or(trait_def_id);
997 DepNode::TraitSelect {
998 trait_def_id: trait_def_id,
999 input_def_id: input_def_id
1003 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
1004 self.trait_ref.input_types()
1007 pub fn self_ty(&self) -> Ty<'tcx> {
1008 self.trait_ref.self_ty()
1012 impl<'tcx> PolyTraitPredicate<'tcx> {
1013 pub fn def_id(&self) -> DefId {
1014 // ok to skip binder since trait def-id does not care about regions
1018 pub fn dep_node(&self) -> DepNode<DefId> {
1019 // ok to skip binder since depnode does not care about regions
1024 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1025 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
1026 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
1028 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1029 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
1030 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1031 pub type PolyRegionOutlivesPredicate<'tcx> = PolyOutlivesPredicate<ty::Region<'tcx>,
1033 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
1035 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1036 pub struct SubtypePredicate<'tcx> {
1037 pub a_is_expected: bool,
1041 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1043 /// This kind of predicate has no *direct* correspondent in the
1044 /// syntax, but it roughly corresponds to the syntactic forms:
1046 /// 1. `T : TraitRef<..., Item=Type>`
1047 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1049 /// In particular, form #1 is "desugared" to the combination of a
1050 /// normal trait predicate (`T : TraitRef<...>`) and one of these
1051 /// predicates. Form #2 is a broader form in that it also permits
1052 /// equality between arbitrary types. Processing an instance of Form
1053 /// #2 eventually yields one of these `ProjectionPredicate`
1054 /// instances to normalize the LHS.
1055 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1056 pub struct ProjectionPredicate<'tcx> {
1057 pub projection_ty: ProjectionTy<'tcx>,
1061 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1063 impl<'tcx> PolyProjectionPredicate<'tcx> {
1064 pub fn item_name(&self) -> Name {
1065 self.0.projection_ty.item_name // safe to skip the binder to access a name
1069 pub trait ToPolyTraitRef<'tcx> {
1070 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1073 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1074 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1075 assert!(!self.has_escaping_regions());
1076 ty::Binder(self.clone())
1080 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1081 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1082 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1086 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
1087 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1088 // Note: unlike with TraitRef::to_poly_trait_ref(),
1089 // self.0.trait_ref is permitted to have escaping regions.
1090 // This is because here `self` has a `Binder` and so does our
1091 // return value, so we are preserving the number of binding
1093 ty::Binder(self.0.projection_ty.trait_ref)
1097 pub trait ToPredicate<'tcx> {
1098 fn to_predicate(&self) -> Predicate<'tcx>;
1101 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1102 fn to_predicate(&self) -> Predicate<'tcx> {
1103 // we're about to add a binder, so let's check that we don't
1104 // accidentally capture anything, or else that might be some
1105 // weird debruijn accounting.
1106 assert!(!self.has_escaping_regions());
1108 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
1109 trait_ref: self.clone()
1114 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1115 fn to_predicate(&self) -> Predicate<'tcx> {
1116 ty::Predicate::Trait(self.to_poly_trait_predicate())
1120 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
1121 fn to_predicate(&self) -> Predicate<'tcx> {
1122 Predicate::Equate(self.clone())
1126 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1127 fn to_predicate(&self) -> Predicate<'tcx> {
1128 Predicate::RegionOutlives(self.clone())
1132 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1133 fn to_predicate(&self) -> Predicate<'tcx> {
1134 Predicate::TypeOutlives(self.clone())
1138 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1139 fn to_predicate(&self) -> Predicate<'tcx> {
1140 Predicate::Projection(self.clone())
1144 impl<'tcx> Predicate<'tcx> {
1145 /// Iterates over the types in this predicate. Note that in all
1146 /// cases this is skipping over a binder, so late-bound regions
1147 /// with depth 0 are bound by the predicate.
1148 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1149 let vec: Vec<_> = match *self {
1150 ty::Predicate::Trait(ref data) => {
1151 data.skip_binder().input_types().collect()
1153 ty::Predicate::Equate(ty::Binder(ref data)) => {
1154 vec![data.0, data.1]
1156 ty::Predicate::Subtype(ty::Binder(SubtypePredicate { a, b, a_is_expected: _ })) => {
1159 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
1162 ty::Predicate::RegionOutlives(..) => {
1165 ty::Predicate::Projection(ref data) => {
1166 let trait_inputs = data.0.projection_ty.trait_ref.input_types();
1167 trait_inputs.chain(Some(data.0.ty)).collect()
1169 ty::Predicate::WellFormed(data) => {
1172 ty::Predicate::ObjectSafe(_trait_def_id) => {
1175 ty::Predicate::ClosureKind(_closure_def_id, _kind) => {
1180 // The only reason to collect into a vector here is that I was
1181 // too lazy to make the full (somewhat complicated) iterator
1182 // type that would be needed here. But I wanted this fn to
1183 // return an iterator conceptually, rather than a `Vec`, so as
1184 // to be closer to `Ty::walk`.
1188 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1190 Predicate::Trait(ref t) => {
1191 Some(t.to_poly_trait_ref())
1193 Predicate::Projection(..) |
1194 Predicate::Equate(..) |
1195 Predicate::Subtype(..) |
1196 Predicate::RegionOutlives(..) |
1197 Predicate::WellFormed(..) |
1198 Predicate::ObjectSafe(..) |
1199 Predicate::ClosureKind(..) |
1200 Predicate::TypeOutlives(..) => {
1207 /// Represents the bounds declared on a particular set of type
1208 /// parameters. Should eventually be generalized into a flag list of
1209 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1210 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1211 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1212 /// the `GenericPredicates` are expressed in terms of the bound type
1213 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1214 /// represented a set of bounds for some particular instantiation,
1215 /// meaning that the generic parameters have been substituted with
1220 /// struct Foo<T,U:Bar<T>> { ... }
1222 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1223 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1224 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1225 /// [usize:Bar<isize>]]`.
1227 pub struct InstantiatedPredicates<'tcx> {
1228 pub predicates: Vec<Predicate<'tcx>>,
1231 impl<'tcx> InstantiatedPredicates<'tcx> {
1232 pub fn empty() -> InstantiatedPredicates<'tcx> {
1233 InstantiatedPredicates { predicates: vec![] }
1236 pub fn is_empty(&self) -> bool {
1237 self.predicates.is_empty()
1241 /// When type checking, we use the `ParamEnv` to track
1242 /// details about the set of where-clauses that are in scope at this
1243 /// particular point.
1244 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1245 pub struct ParamEnv<'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 Slice<ty::Predicate<'tcx>>,
1252 impl<'tcx> ParamEnv<'tcx> {
1253 /// Creates a suitable environment in which to perform trait
1254 /// queries on the given value. This will either be `self` *or*
1255 /// the empty environment, depending on whether `value` references
1256 /// type parameters that are in scope. (If it doesn't, then any
1257 /// judgements should be completely independent of the context,
1258 /// and hence we can safely use the empty environment so as to
1259 /// enable more sharing across functions.)
1261 /// NB: This is a mildly dubious thing to do, in that a function
1262 /// (or other environment) might have wacky where-clauses like
1263 /// `where Box<u32>: Copy`, which are clearly never
1264 /// satisfiable. The code will at present ignore these,
1265 /// effectively, when type-checking the body of said
1266 /// function. This preserves existing behavior in any
1267 /// case. --nmatsakis
1268 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1269 assert!(!value.needs_infer());
1270 if value.has_param_types() || value.has_self_ty() {
1277 param_env: ParamEnv::empty(),
1284 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1285 pub struct ParamEnvAnd<'tcx, T> {
1286 pub param_env: ParamEnv<'tcx>,
1290 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1291 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1292 (self.param_env, self.value)
1296 #[derive(Copy, Clone, Debug)]
1297 pub struct Destructor {
1298 /// The def-id of the destructor method
1303 flags AdtFlags: u32 {
1304 const NO_ADT_FLAGS = 0,
1305 const IS_ENUM = 1 << 0,
1306 const IS_PHANTOM_DATA = 1 << 1,
1307 const IS_FUNDAMENTAL = 1 << 2,
1308 const IS_UNION = 1 << 3,
1309 const IS_BOX = 1 << 4,
1314 pub struct VariantDef {
1315 /// The variant's DefId. If this is a tuple-like struct,
1316 /// this is the DefId of the struct's ctor.
1318 pub name: Name, // struct's name if this is a struct
1319 pub discr: VariantDiscr,
1320 pub fields: Vec<FieldDef>,
1321 pub ctor_kind: CtorKind,
1324 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1325 pub enum VariantDiscr {
1326 /// Explicit value for this variant, i.e. `X = 123`.
1327 /// The `DefId` corresponds to the embedded constant.
1330 /// The previous variant's discriminant plus one.
1331 /// For efficiency reasons, the distance from the
1332 /// last `Explicit` discriminant is being stored,
1333 /// or `0` for the first variant, if it has none.
1338 pub struct FieldDef {
1341 pub vis: Visibility,
1344 /// The definition of an abstract data type - a struct or enum.
1346 /// These are all interned (by intern_adt_def) into the adt_defs
1350 pub variants: Vec<VariantDef>,
1352 pub repr: ReprOptions,
1355 impl PartialEq for AdtDef {
1356 // AdtDef are always interned and this is part of TyS equality
1358 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1361 impl Eq for AdtDef {}
1363 impl Hash for AdtDef {
1365 fn hash<H: Hasher>(&self, s: &mut H) {
1366 (self as *const AdtDef).hash(s)
1370 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1371 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1376 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1379 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for AdtDef {
1380 fn hash_stable<W: StableHasherResult>(&self,
1381 hcx: &mut StableHashingContext<'a, 'tcx>,
1382 hasher: &mut StableHasher<W>) {
1390 did.hash_stable(hcx, hasher);
1391 variants.hash_stable(hcx, hasher);
1392 flags.hash_stable(hcx, hasher);
1393 repr.hash_stable(hcx, hasher);
1397 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1398 pub enum AdtKind { Struct, Union, Enum }
1401 #[derive(RustcEncodable, RustcDecodable, Default)]
1402 flags ReprFlags: u8 {
1403 const IS_C = 1 << 0,
1404 const IS_PACKED = 1 << 1,
1405 const IS_SIMD = 1 << 2,
1406 // Internal only for now. If true, don't reorder fields.
1407 const IS_LINEAR = 1 << 3,
1409 // Any of these flags being set prevent field reordering optimisation.
1410 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1411 ReprFlags::IS_PACKED.bits |
1412 ReprFlags::IS_SIMD.bits |
1413 ReprFlags::IS_LINEAR.bits,
1417 impl_stable_hash_for!(struct ReprFlags {
1423 /// Represents the repr options provided by the user,
1424 #[derive(Copy, Clone, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1425 pub struct ReprOptions {
1426 pub int: Option<attr::IntType>,
1428 pub flags: ReprFlags,
1431 impl_stable_hash_for!(struct ReprOptions {
1438 pub fn new(tcx: TyCtxt, did: DefId) -> ReprOptions {
1439 let mut flags = ReprFlags::empty();
1440 let mut size = None;
1441 let mut max_align = 0;
1442 for attr in tcx.get_attrs(did).iter() {
1443 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1444 flags.insert(match r {
1445 attr::ReprExtern => ReprFlags::IS_C,
1446 attr::ReprPacked => ReprFlags::IS_PACKED,
1447 attr::ReprSimd => ReprFlags::IS_SIMD,
1448 attr::ReprInt(i) => {
1452 attr::ReprAlign(align) => {
1453 max_align = cmp::max(align, max_align);
1460 // FIXME(eddyb) This is deprecated and should be removed.
1461 if tcx.has_attr(did, "simd") {
1462 flags.insert(ReprFlags::IS_SIMD);
1465 // This is here instead of layout because the choice must make it into metadata.
1466 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1467 flags.insert(ReprFlags::IS_LINEAR);
1469 ReprOptions { int: size, align: max_align, flags: flags }
1473 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1475 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1477 pub fn packed(&self) -> bool { self.flags.contains(ReprFlags::IS_PACKED) }
1479 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1481 pub fn discr_type(&self) -> attr::IntType {
1482 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Is))
1485 /// Returns true if this `#[repr()]` should inhabit "smart enum
1486 /// layout" optimizations, such as representing `Foo<&T>` as a
1488 pub fn inhibit_enum_layout_opt(&self) -> bool {
1489 self.c() || self.int.is_some()
1493 impl<'a, 'gcx, 'tcx> AdtDef {
1497 variants: Vec<VariantDef>,
1498 repr: ReprOptions) -> Self {
1499 let mut flags = AdtFlags::NO_ADT_FLAGS;
1500 let attrs = tcx.get_attrs(did);
1501 if attr::contains_name(&attrs, "fundamental") {
1502 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1504 if Some(did) == tcx.lang_items.phantom_data() {
1505 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1507 if Some(did) == tcx.lang_items.owned_box() {
1508 flags = flags | AdtFlags::IS_BOX;
1511 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
1512 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
1513 AdtKind::Struct => {}
1524 pub fn is_struct(&self) -> bool {
1525 !self.is_union() && !self.is_enum()
1529 pub fn is_union(&self) -> bool {
1530 self.flags.intersects(AdtFlags::IS_UNION)
1534 pub fn is_enum(&self) -> bool {
1535 self.flags.intersects(AdtFlags::IS_ENUM)
1538 /// Returns the kind of the ADT - Struct or Enum.
1540 pub fn adt_kind(&self) -> AdtKind {
1543 } else if self.is_union() {
1550 pub fn descr(&self) -> &'static str {
1551 match self.adt_kind() {
1552 AdtKind::Struct => "struct",
1553 AdtKind::Union => "union",
1554 AdtKind::Enum => "enum",
1558 pub fn variant_descr(&self) -> &'static str {
1559 match self.adt_kind() {
1560 AdtKind::Struct => "struct",
1561 AdtKind::Union => "union",
1562 AdtKind::Enum => "variant",
1566 /// Returns whether this type is #[fundamental] for the purposes
1567 /// of coherence checking.
1569 pub fn is_fundamental(&self) -> bool {
1570 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
1573 /// Returns true if this is PhantomData<T>.
1575 pub fn is_phantom_data(&self) -> bool {
1576 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
1579 /// Returns true if this is Box<T>.
1581 pub fn is_box(&self) -> bool {
1582 self.flags.intersects(AdtFlags::IS_BOX)
1585 /// Returns whether this type has a destructor.
1586 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
1587 self.destructor(tcx).is_some()
1590 /// Asserts this is a struct and returns the struct's unique
1592 pub fn struct_variant(&self) -> &VariantDef {
1593 assert!(!self.is_enum());
1598 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
1599 tcx.predicates_of(self.did)
1602 /// Returns an iterator over all fields contained
1605 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
1606 self.variants.iter().flat_map(|v| v.fields.iter())
1610 pub fn is_univariant(&self) -> bool {
1611 self.variants.len() == 1
1614 pub fn is_payloadfree(&self) -> bool {
1615 !self.variants.is_empty() &&
1616 self.variants.iter().all(|v| v.fields.is_empty())
1619 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
1622 .find(|v| v.did == vid)
1623 .expect("variant_with_id: unknown variant")
1626 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1629 .position(|v| v.did == vid)
1630 .expect("variant_index_with_id: unknown variant")
1633 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
1635 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
1636 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
1637 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.struct_variant(),
1638 _ => bug!("unexpected def {:?} in variant_of_def", def)
1643 pub fn discriminants(&'a self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1644 -> impl Iterator<Item=ConstInt> + 'a {
1645 let repr_type = self.repr.discr_type();
1646 let initial = repr_type.initial_discriminant(tcx.global_tcx());
1647 let mut prev_discr = None::<ConstInt>;
1648 self.variants.iter().map(move |v| {
1649 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr());
1650 if let VariantDiscr::Explicit(expr_did) = v.discr {
1651 let substs = Substs::empty();
1652 match tcx.const_eval((expr_did, substs)) {
1653 Ok(ConstVal::Integral(v)) => {
1657 if !expr_did.is_local() {
1658 span_bug!(tcx.def_span(expr_did),
1659 "variant discriminant evaluation succeeded \
1660 in its crate but failed locally: {:?}", err);
1665 prev_discr = Some(discr);
1671 /// Compute the discriminant value used by a specific variant.
1672 /// Unlike `discriminants`, this is (amortized) constant-time,
1673 /// only doing at most one query for evaluating an explicit
1674 /// discriminant (the last one before the requested variant),
1675 /// assuming there are no constant-evaluation errors there.
1676 pub fn discriminant_for_variant(&self,
1677 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1678 variant_index: usize)
1680 let repr_type = self.repr.discr_type();
1681 let mut explicit_value = repr_type.initial_discriminant(tcx.global_tcx());
1682 let mut explicit_index = variant_index;
1684 match self.variants[explicit_index].discr {
1685 ty::VariantDiscr::Relative(0) => break,
1686 ty::VariantDiscr::Relative(distance) => {
1687 explicit_index -= distance;
1689 ty::VariantDiscr::Explicit(expr_did) => {
1690 let substs = Substs::empty();
1691 match tcx.const_eval((expr_did, substs)) {
1692 Ok(ConstVal::Integral(v)) => {
1697 if !expr_did.is_local() {
1698 span_bug!(tcx.def_span(expr_did),
1699 "variant discriminant evaluation succeeded \
1700 in its crate but failed locally: {:?}", err);
1702 if explicit_index == 0 {
1705 explicit_index -= 1;
1711 let discr = explicit_value.to_u128_unchecked()
1712 .wrapping_add((variant_index - explicit_index) as u128);
1714 attr::UnsignedInt(ty) => {
1715 ConstInt::new_unsigned_truncating(discr, ty,
1716 tcx.sess.target.uint_type)
1718 attr::SignedInt(ty) => {
1719 ConstInt::new_signed_truncating(discr as i128, ty,
1720 tcx.sess.target.int_type)
1725 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
1726 tcx.adt_destructor(self.did)
1729 /// Returns a list of types such that `Self: Sized` if and only
1730 /// if that type is Sized, or `TyErr` if this type is recursive.
1732 /// Oddly enough, checking that the sized-constraint is Sized is
1733 /// actually more expressive than checking all members:
1734 /// the Sized trait is inductive, so an associated type that references
1735 /// Self would prevent its containing ADT from being Sized.
1737 /// Due to normalization being eager, this applies even if
1738 /// the associated type is behind a pointer, e.g. issue #31299.
1739 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
1740 match queries::adt_sized_constraint::try_get(tcx, DUMMY_SP, self.did) {
1743 debug!("adt_sized_constraint: {:?} is recursive", self);
1744 // This should be reported as an error by `check_representable`.
1746 // Consider the type as Sized in the meanwhile to avoid
1748 tcx.intern_type_list(&[tcx.types.err])
1753 fn sized_constraint_for_ty(&self,
1754 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1757 let result = match ty.sty {
1758 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
1759 TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
1760 TyArray(..) | TyClosure(..) | TyNever => {
1764 TyStr | TyDynamic(..) | TySlice(_) | TyError => {
1765 // these are never sized - return the target type
1769 TyTuple(ref tys, _) => {
1772 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
1776 TyAdt(adt, substs) => {
1778 let adt_tys = adt.sized_constraint(tcx);
1779 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
1782 .map(|ty| ty.subst(tcx, substs))
1783 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
1787 TyProjection(..) | TyAnon(..) => {
1788 // must calculate explicitly.
1789 // FIXME: consider special-casing always-Sized projections
1794 // perf hack: if there is a `T: Sized` bound, then
1795 // we know that `T` is Sized and do not need to check
1798 let sized_trait = match tcx.lang_items.sized_trait() {
1800 _ => return vec![ty]
1802 let sized_predicate = Binder(TraitRef {
1803 def_id: sized_trait,
1804 substs: tcx.mk_substs_trait(ty, &[])
1806 let predicates = tcx.predicates_of(self.did).predicates;
1807 if predicates.into_iter().any(|p| p == sized_predicate) {
1815 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
1819 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
1824 impl<'a, 'gcx, 'tcx> VariantDef {
1826 pub fn find_field_named(&self,
1828 -> Option<&FieldDef> {
1829 self.fields.iter().find(|f| f.name == name)
1833 pub fn index_of_field_named(&self,
1836 self.fields.iter().position(|f| f.name == name)
1840 pub fn field_named(&self, name: ast::Name) -> &FieldDef {
1841 self.find_field_named(name).unwrap()
1845 impl<'a, 'gcx, 'tcx> FieldDef {
1846 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1847 tcx.type_of(self.did).subst(tcx, subst)
1851 /// Records the substitutions used to translate the polytype for an
1852 /// item into the monotype of an item reference.
1853 #[derive(Clone, RustcEncodable, RustcDecodable)]
1854 pub struct ItemSubsts<'tcx> {
1855 pub substs: &'tcx Substs<'tcx>,
1858 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1859 pub enum ClosureKind {
1860 // Warning: Ordering is significant here! The ordering is chosen
1861 // because the trait Fn is a subtrait of FnMut and so in turn, and
1862 // hence we order it so that Fn < FnMut < FnOnce.
1868 impl<'a, 'tcx> ClosureKind {
1869 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
1871 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
1872 ClosureKind::FnMut => {
1873 tcx.require_lang_item(FnMutTraitLangItem)
1875 ClosureKind::FnOnce => {
1876 tcx.require_lang_item(FnOnceTraitLangItem)
1881 /// True if this a type that impls this closure kind
1882 /// must also implement `other`.
1883 pub fn extends(self, other: ty::ClosureKind) -> bool {
1884 match (self, other) {
1885 (ClosureKind::Fn, ClosureKind::Fn) => true,
1886 (ClosureKind::Fn, ClosureKind::FnMut) => true,
1887 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
1888 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
1889 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
1890 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
1896 impl<'tcx> TyS<'tcx> {
1897 /// Iterator that walks `self` and any types reachable from
1898 /// `self`, in depth-first order. Note that just walks the types
1899 /// that appear in `self`, it does not descend into the fields of
1900 /// structs or variants. For example:
1903 /// isize => { isize }
1904 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
1905 /// [isize] => { [isize], isize }
1907 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
1908 TypeWalker::new(self)
1911 /// Iterator that walks the immediate children of `self`. Hence
1912 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
1913 /// (but not `i32`, like `walk`).
1914 pub fn walk_shallow(&'tcx self) -> AccIntoIter<walk::TypeWalkerArray<'tcx>> {
1915 walk::walk_shallow(self)
1918 /// Walks `ty` and any types appearing within `ty`, invoking the
1919 /// callback `f` on each type. If the callback returns false, then the
1920 /// children of the current type are ignored.
1922 /// Note: prefer `ty.walk()` where possible.
1923 pub fn maybe_walk<F>(&'tcx self, mut f: F)
1924 where F : FnMut(Ty<'tcx>) -> bool
1926 let mut walker = self.walk();
1927 while let Some(ty) = walker.next() {
1929 walker.skip_current_subtree();
1935 impl<'tcx> ItemSubsts<'tcx> {
1936 pub fn is_noop(&self) -> bool {
1937 self.substs.is_noop()
1941 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1942 pub enum LvaluePreference {
1947 impl LvaluePreference {
1948 pub fn from_mutbl(m: hir::Mutability) -> Self {
1950 hir::MutMutable => PreferMutLvalue,
1951 hir::MutImmutable => NoPreference,
1957 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
1959 hir::MutMutable => MutBorrow,
1960 hir::MutImmutable => ImmBorrow,
1964 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
1965 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
1966 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
1968 pub fn to_mutbl_lossy(self) -> hir::Mutability {
1970 MutBorrow => hir::MutMutable,
1971 ImmBorrow => hir::MutImmutable,
1973 // We have no type corresponding to a unique imm borrow, so
1974 // use `&mut`. It gives all the capabilities of an `&uniq`
1975 // and hence is a safe "over approximation".
1976 UniqueImmBorrow => hir::MutMutable,
1980 pub fn to_user_str(&self) -> &'static str {
1982 MutBorrow => "mutable",
1983 ImmBorrow => "immutable",
1984 UniqueImmBorrow => "uniquely immutable",
1989 #[derive(Debug, Clone)]
1990 pub enum Attributes<'gcx> {
1991 Owned(Rc<[ast::Attribute]>),
1992 Borrowed(&'gcx [ast::Attribute])
1995 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
1996 type Target = [ast::Attribute];
1998 fn deref(&self) -> &[ast::Attribute] {
2000 &Attributes::Owned(ref data) => &data,
2001 &Attributes::Borrowed(data) => data
2006 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2007 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2008 self.typeck_tables_of(self.hir.body_owner_def_id(body))
2011 /// Returns an iterator of the def-ids for all body-owners in this
2012 /// crate. If you would prefer to iterate over the bodies
2013 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
2014 pub fn body_owners(self) -> impl Iterator<Item = DefId> + 'a {
2018 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
2021 pub fn expr_span(self, id: NodeId) -> Span {
2022 match self.hir.find(id) {
2023 Some(hir_map::NodeExpr(e)) => {
2027 bug!("Node id {} is not an expr: {:?}", id, f);
2030 bug!("Node id {} is not present in the node map", id);
2035 pub fn local_var_name_str(self, id: NodeId) -> InternedString {
2036 match self.hir.find(id) {
2037 Some(hir_map::NodeLocal(pat)) => {
2039 hir::PatKind::Binding(_, _, ref path1, _) => path1.node.as_str(),
2041 bug!("Variable id {} maps to {:?}, not local", id, pat);
2045 r => bug!("Variable id {} maps to {:?}, not local", id, r),
2049 pub fn expr_is_lval(self, expr: &hir::Expr) -> bool {
2051 hir::ExprPath(hir::QPath::Resolved(_, ref path)) => {
2053 Def::Local(..) | Def::Upvar(..) | Def::Static(..) | Def::Err => true,
2058 hir::ExprType(ref e, _) => {
2059 self.expr_is_lval(e)
2062 hir::ExprUnary(hir::UnDeref, _) |
2063 hir::ExprField(..) |
2064 hir::ExprTupField(..) |
2065 hir::ExprIndex(..) => {
2069 // Partially qualified paths in expressions can only legally
2070 // refer to associated items which are always rvalues.
2071 hir::ExprPath(hir::QPath::TypeRelative(..)) |
2074 hir::ExprMethodCall(..) |
2075 hir::ExprStruct(..) |
2078 hir::ExprMatch(..) |
2079 hir::ExprClosure(..) |
2080 hir::ExprBlock(..) |
2081 hir::ExprRepeat(..) |
2082 hir::ExprArray(..) |
2083 hir::ExprBreak(..) |
2084 hir::ExprAgain(..) |
2086 hir::ExprWhile(..) |
2088 hir::ExprAssign(..) |
2089 hir::ExprInlineAsm(..) |
2090 hir::ExprAssignOp(..) |
2092 hir::ExprUnary(..) |
2094 hir::ExprAddrOf(..) |
2095 hir::ExprBinary(..) |
2096 hir::ExprCast(..) => {
2102 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2103 self.associated_items(id)
2104 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2108 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2109 self.associated_items(did).any(|item| {
2110 item.relevant_for_never()
2114 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2115 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2116 match self.hir.get(node_id) {
2117 hir_map::NodeTraitItem(_) | hir_map::NodeImplItem(_) => true,
2121 match self.describe_def(def_id).expect("no def for def-id") {
2122 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2127 if is_associated_item {
2128 Some(self.associated_item(def_id))
2134 fn associated_item_from_trait_item_ref(self,
2135 parent_def_id: DefId,
2136 parent_vis: &hir::Visibility,
2137 trait_item_ref: &hir::TraitItemRef)
2139 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2140 let (kind, has_self) = match trait_item_ref.kind {
2141 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2142 hir::AssociatedItemKind::Method { has_self } => {
2143 (ty::AssociatedKind::Method, has_self)
2145 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2149 name: trait_item_ref.name,
2151 // Visibility of trait items is inherited from their traits.
2152 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2153 defaultness: trait_item_ref.defaultness,
2155 container: TraitContainer(parent_def_id),
2156 method_has_self_argument: has_self
2160 fn associated_item_from_impl_item_ref(self,
2161 parent_def_id: DefId,
2162 impl_item_ref: &hir::ImplItemRef)
2164 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2165 let (kind, has_self) = match impl_item_ref.kind {
2166 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2167 hir::AssociatedItemKind::Method { has_self } => {
2168 (ty::AssociatedKind::Method, has_self)
2170 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2173 ty::AssociatedItem {
2174 name: impl_item_ref.name,
2176 // Visibility of trait impl items doesn't matter.
2177 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2178 defaultness: impl_item_ref.defaultness,
2180 container: ImplContainer(parent_def_id),
2181 method_has_self_argument: has_self
2185 #[inline] // FIXME(#35870) Avoid closures being unexported due to impl Trait.
2186 pub fn associated_items(self, def_id: DefId)
2187 -> impl Iterator<Item = ty::AssociatedItem> + 'a {
2188 let def_ids = self.associated_item_def_ids(def_id);
2189 (0..def_ids.len()).map(move |i| self.associated_item(def_ids[i]))
2192 /// Returns true if the impls are the same polarity and are implementing
2193 /// a trait which contains no items
2194 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2195 if !self.sess.features.borrow().overlapping_marker_traits {
2198 let trait1_is_empty = self.impl_trait_ref(def_id1)
2199 .map_or(false, |trait_ref| {
2200 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2202 let trait2_is_empty = self.impl_trait_ref(def_id2)
2203 .map_or(false, |trait_ref| {
2204 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2206 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2211 // Returns `ty::VariantDef` if `def` refers to a struct,
2212 // or variant or their constructors, panics otherwise.
2213 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2215 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2216 let enum_did = self.parent_def_id(did).unwrap();
2217 self.adt_def(enum_did).variant_with_id(did)
2219 Def::Struct(did) | Def::Union(did) => {
2220 self.adt_def(did).struct_variant()
2222 Def::StructCtor(ctor_did, ..) => {
2223 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2224 self.adt_def(did).struct_variant()
2226 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2230 pub fn def_key(self, id: DefId) -> hir_map::DefKey {
2232 self.hir.def_key(id)
2234 self.sess.cstore.def_key(id)
2238 /// Convert a `DefId` into its fully expanded `DefPath` (every
2239 /// `DefId` is really just an interned def-path).
2241 /// Note that if `id` is not local to this crate, the result will
2242 /// be a non-local `DefPath`.
2243 pub fn def_path(self, id: DefId) -> hir_map::DefPath {
2245 self.hir.def_path(id)
2247 self.sess.cstore.def_path(id)
2252 pub fn def_path_hash(self, def_id: DefId) -> ich::Fingerprint {
2253 if def_id.is_local() {
2254 self.hir.definitions().def_path_hash(def_id.index)
2256 self.sess.cstore.def_path_hash(def_id)
2260 pub fn vis_is_accessible_from(self, vis: Visibility, block: NodeId) -> bool {
2261 vis.is_accessible_from(self.hir.local_def_id(self.hir.get_module_parent(block)), self)
2264 pub fn item_name(self, id: DefId) -> ast::Name {
2265 if let Some(id) = self.hir.as_local_node_id(id) {
2267 } else if id.index == CRATE_DEF_INDEX {
2268 self.sess.cstore.original_crate_name(id.krate)
2270 let def_key = self.sess.cstore.def_key(id);
2271 // The name of a StructCtor is that of its struct parent.
2272 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2273 self.item_name(DefId {
2275 index: def_key.parent.unwrap()
2278 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2279 bug!("item_name: no name for {:?}", self.def_path(id));
2285 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2286 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2290 ty::InstanceDef::Item(did) => {
2291 self.optimized_mir(did)
2293 ty::InstanceDef::Intrinsic(..) |
2294 ty::InstanceDef::FnPtrShim(..) |
2295 ty::InstanceDef::Virtual(..) |
2296 ty::InstanceDef::ClosureOnceShim { .. } |
2297 ty::InstanceDef::DropGlue(..) => {
2298 self.mir_shims(instance)
2303 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2304 /// Returns None if there is no MIR for the DefId
2305 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2306 if self.is_mir_available(did) {
2307 Some(self.optimized_mir(did))
2313 /// Get the attributes of a definition.
2314 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2315 if let Some(id) = self.hir.as_local_node_id(did) {
2316 Attributes::Borrowed(self.hir.attrs(id))
2318 Attributes::Owned(self.item_attrs(did))
2322 /// Determine whether an item is annotated with an attribute
2323 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2324 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2327 pub fn trait_has_default_impl(self, trait_def_id: DefId) -> bool {
2328 self.trait_def(trait_def_id).has_default_impl
2331 /// Given the def_id of an impl, return the def_id of the trait it implements.
2332 /// If it implements no trait, return `None`.
2333 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2334 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2337 /// If the given def ID describes a method belonging to an impl, return the
2338 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2339 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2340 let item = if def_id.krate != LOCAL_CRATE {
2341 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2342 Some(self.associated_item(def_id))
2347 self.opt_associated_item(def_id)
2351 Some(trait_item) => {
2352 match trait_item.container {
2353 TraitContainer(_) => None,
2354 ImplContainer(def_id) => Some(def_id),
2361 pub fn node_scope_region(self, id: NodeId) -> Region<'tcx> {
2362 self.mk_region(ty::ReScope(CodeExtent::Misc(id)))
2365 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2366 /// with the name of the crate containing the impl.
2367 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2368 if impl_did.is_local() {
2369 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2370 Ok(self.hir.span(node_id))
2372 Err(self.sess.cstore.crate_name(impl_did.krate))
2377 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2378 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2379 F: FnOnce(&[hir::Freevar]) -> T,
2381 match self.freevars.borrow().get(&fid) {
2383 Some(d) => f(&d[..])
2388 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
2391 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2392 let parent_id = tcx.hir.get_parent(id);
2393 let parent_def_id = tcx.hir.local_def_id(parent_id);
2394 let parent_item = tcx.hir.expect_item(parent_id);
2395 match parent_item.node {
2396 hir::ItemImpl(.., ref impl_item_refs) => {
2397 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2398 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2400 debug_assert_eq!(assoc_item.def_id, def_id);
2405 hir::ItemTrait(.., ref trait_item_refs) => {
2406 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2407 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2410 debug_assert_eq!(assoc_item.def_id, def_id);
2418 span_bug!(parent_item.span,
2419 "unexpected parent of trait or impl item or item not found: {:?}",
2423 /// Calculates the Sized-constraint.
2425 /// In fact, there are only a few options for the types in the constraint:
2426 /// - an obviously-unsized type
2427 /// - a type parameter or projection whose Sizedness can't be known
2428 /// - a tuple of type parameters or projections, if there are multiple
2430 /// - a TyError, if a type contained itself. The representability
2431 /// check should catch this case.
2432 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2434 -> &'tcx [Ty<'tcx>] {
2435 let def = tcx.adt_def(def_id);
2437 let result = tcx.intern_type_list(&def.variants.iter().flat_map(|v| {
2440 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2441 }).collect::<Vec<_>>());
2443 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2448 /// Calculates the dtorck constraint for a type.
2449 fn adt_dtorck_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2451 -> DtorckConstraint<'tcx> {
2452 let def = tcx.adt_def(def_id);
2453 let span = tcx.def_span(def_id);
2454 debug!("dtorck_constraint: {:?}", def);
2456 if def.is_phantom_data() {
2457 let result = DtorckConstraint {
2460 tcx.mk_param_from_def(&tcx.generics_of(def_id).types[0])
2463 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2467 let mut result = def.all_fields()
2468 .map(|field| tcx.type_of(field.did))
2469 .map(|fty| tcx.dtorck_constraint_for_ty(span, fty, 0, fty))
2470 .collect::<Result<DtorckConstraint, ErrorReported>>()
2471 .unwrap_or(DtorckConstraint::empty());
2472 result.outlives.extend(tcx.destructor_constraints(def));
2475 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2480 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2483 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2484 let item = tcx.hir.expect_item(id);
2485 let vec: Vec<_> = match item.node {
2486 hir::ItemTrait(.., ref trait_item_refs) => {
2487 trait_item_refs.iter()
2488 .map(|trait_item_ref| trait_item_ref.id)
2489 .map(|id| tcx.hir.local_def_id(id.node_id))
2492 hir::ItemImpl(.., ref impl_item_refs) => {
2493 impl_item_refs.iter()
2494 .map(|impl_item_ref| impl_item_ref.id)
2495 .map(|id| tcx.hir.local_def_id(id.node_id))
2498 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2503 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
2504 tcx.hir.span_if_local(def_id).unwrap()
2507 /// If the given def ID describes an item belonging to a trait,
2508 /// return the ID of the trait that the trait item belongs to.
2509 /// Otherwise, return `None`.
2510 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
2511 tcx.opt_associated_item(def_id)
2512 .and_then(|associated_item| {
2513 match associated_item.container {
2514 TraitContainer(def_id) => Some(def_id),
2515 ImplContainer(_) => None
2520 /// See `ParamEnv` struct def'n for details.
2521 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2524 // Compute the bounds on Self and the type parameters.
2526 let bounds = tcx.predicates_of(def_id).instantiate_identity(tcx);
2527 let predicates = bounds.predicates;
2529 // Finally, we have to normalize the bounds in the environment, in
2530 // case they contain any associated type projections. This process
2531 // can yield errors if the put in illegal associated types, like
2532 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2533 // report these errors right here; this doesn't actually feel
2534 // right to me, because constructing the environment feels like a
2535 // kind of a "idempotent" action, but I'm not sure where would be
2536 // a better place. In practice, we construct environments for
2537 // every fn once during type checking, and we'll abort if there
2538 // are any errors at that point, so after type checking you can be
2539 // sure that this will succeed without errors anyway.
2541 let unnormalized_env = ty::ParamEnv::new(tcx.intern_predicates(&predicates));
2543 let body_id = tcx.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
2544 tcx.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_id)
2546 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
2547 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
2550 pub fn provide(providers: &mut ty::maps::Providers) {
2551 util::provide(providers);
2552 *providers = ty::maps::Providers {
2554 associated_item_def_ids,
2555 adt_sized_constraint,
2556 adt_dtorck_constraint,
2560 trait_impls_of: trait_def::trait_impls_of_provider,
2561 relevant_trait_impls_for: trait_def::relevant_trait_impls_provider,
2566 pub fn provide_extern(providers: &mut ty::maps::Providers) {
2567 *providers = ty::maps::Providers {
2568 adt_sized_constraint,
2569 adt_dtorck_constraint,
2570 trait_impls_of: trait_def::trait_impls_of_provider,
2571 relevant_trait_impls_for: trait_def::relevant_trait_impls_provider,
2578 /// A map for the local crate mapping each type to a vector of its
2579 /// inherent impls. This is not meant to be used outside of coherence;
2580 /// rather, you should request the vector for a specific type via
2581 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2582 /// (constructing this map requires touching the entire crate).
2583 #[derive(Clone, Debug)]
2584 pub struct CrateInherentImpls {
2585 pub inherent_impls: DefIdMap<Rc<Vec<DefId>>>,
2588 /// A set of constraints that need to be satisfied in order for
2589 /// a type to be valid for destruction.
2590 #[derive(Clone, Debug)]
2591 pub struct DtorckConstraint<'tcx> {
2592 /// Types that are required to be alive in order for this
2593 /// type to be valid for destruction.
2594 pub outlives: Vec<ty::subst::Kind<'tcx>>,
2595 /// Types that could not be resolved: projections and params.
2596 pub dtorck_types: Vec<Ty<'tcx>>,
2599 impl<'tcx> FromIterator<DtorckConstraint<'tcx>> for DtorckConstraint<'tcx>
2601 fn from_iter<I: IntoIterator<Item=DtorckConstraint<'tcx>>>(iter: I) -> Self {
2602 let mut result = Self::empty();
2604 for constraint in iter {
2605 result.outlives.extend(constraint.outlives);
2606 result.dtorck_types.extend(constraint.dtorck_types);
2614 impl<'tcx> DtorckConstraint<'tcx> {
2615 fn empty() -> DtorckConstraint<'tcx> {
2618 dtorck_types: vec![]
2622 fn dedup<'a>(&mut self) {
2623 let mut outlives = FxHashSet();
2624 let mut dtorck_types = FxHashSet();
2626 self.outlives.retain(|&val| outlives.replace(val).is_none());
2627 self.dtorck_types.retain(|&val| dtorck_types.replace(val).is_none());
2631 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord)]
2632 pub struct SymbolName {
2633 // FIXME: we don't rely on interning or equality here - better have
2634 // this be a `&'tcx str`.
2635 pub name: InternedString
2638 impl Deref for SymbolName {
2641 fn deref(&self) -> &str { &self.name }
2644 impl fmt::Display for SymbolName {
2645 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2646 fmt::Display::fmt(&self.name, fmt)