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;
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, Ident, NodeId};
50 use syntax::ext::hygiene::{Mark, SyntaxContext};
51 use syntax::symbol::{Symbol, InternedString};
52 use syntax_pos::{DUMMY_SP, Span};
53 use rustc_const_math::ConstInt;
55 use rustc_data_structures::accumulate_vec::IntoIter as AccIntoIter;
56 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
58 use rustc_data_structures::transitive_relation::TransitiveRelation;
62 pub use self::sty::{Binder, DebruijnIndex};
63 pub use self::sty::{FnSig, PolyFnSig};
64 pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
65 pub use self::sty::{ClosureSubsts, TypeAndMut};
66 pub use self::sty::{TraitRef, TypeVariants, PolyTraitRef};
67 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
68 pub use self::sty::{ExistentialProjection, PolyExistentialProjection};
69 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
70 pub use self::sty::RegionKind;
71 pub use self::sty::Issue32330;
72 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid, SkolemizedRegionVid};
73 pub use self::sty::BoundRegion::*;
74 pub use self::sty::InferTy::*;
75 pub use self::sty::RegionKind::*;
76 pub use self::sty::TypeVariants::*;
78 pub use self::context::{TyCtxt, GlobalArenas, tls};
79 pub use self::context::{Lift, TypeckTables};
81 pub use self::instance::{Instance, InstanceDef};
83 pub use self::trait_def::TraitDef;
85 pub use self::maps::queries;
92 pub mod inhabitedness;
109 mod structural_impls;
114 /// The complete set of all analyses described in this module. This is
115 /// produced by the driver and fed to trans and later passes.
117 /// NB: These contents are being migrated into queries using the
118 /// *on-demand* infrastructure.
120 pub struct CrateAnalysis {
121 pub access_levels: Rc<AccessLevels>,
122 pub reachable: Rc<NodeSet>,
124 pub glob_map: Option<hir::GlobMap>,
128 pub struct Resolutions {
129 pub freevars: FreevarMap,
130 pub trait_map: TraitMap,
131 pub maybe_unused_trait_imports: NodeSet,
132 pub export_map: ExportMap,
135 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
136 pub enum AssociatedItemContainer {
137 TraitContainer(DefId),
138 ImplContainer(DefId),
141 impl AssociatedItemContainer {
142 pub fn id(&self) -> DefId {
144 TraitContainer(id) => id,
145 ImplContainer(id) => id,
150 /// The "header" of an impl is everything outside the body: a Self type, a trait
151 /// ref (in the case of a trait impl), and a set of predicates (from the
152 /// bounds/where clauses).
153 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
154 pub struct ImplHeader<'tcx> {
155 pub impl_def_id: DefId,
156 pub self_ty: Ty<'tcx>,
157 pub trait_ref: Option<TraitRef<'tcx>>,
158 pub predicates: Vec<Predicate<'tcx>>,
161 #[derive(Copy, Clone, Debug)]
162 pub struct AssociatedItem {
165 pub kind: AssociatedKind,
167 pub defaultness: hir::Defaultness,
168 pub container: AssociatedItemContainer,
170 /// Whether this is a method with an explicit self
171 /// as its first argument, allowing method calls.
172 pub method_has_self_argument: bool,
175 #[derive(Copy, Clone, PartialEq, Eq, Debug, RustcEncodable, RustcDecodable)]
176 pub enum AssociatedKind {
182 impl AssociatedItem {
183 pub fn def(&self) -> Def {
185 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
186 AssociatedKind::Method => Def::Method(self.def_id),
187 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
191 /// Tests whether the associated item admits a non-trivial implementation
193 pub fn relevant_for_never<'tcx>(&self) -> bool {
195 AssociatedKind::Const => true,
196 AssociatedKind::Type => true,
197 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
198 AssociatedKind::Method => !self.method_has_self_argument,
203 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
204 pub enum Visibility {
205 /// Visible everywhere (including in other crates).
207 /// Visible only in the given crate-local module.
209 /// Not visible anywhere in the local crate. This is the visibility of private external items.
213 pub trait DefIdTree: Copy {
214 fn parent(self, id: DefId) -> Option<DefId>;
216 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
217 if descendant.krate != ancestor.krate {
221 while descendant != ancestor {
222 match self.parent(descendant) {
223 Some(parent) => descendant = parent,
224 None => return false,
231 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
232 fn parent(self, id: DefId) -> Option<DefId> {
233 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
238 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt) -> Self {
240 hir::Public => Visibility::Public,
241 hir::Visibility::Crate => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
242 hir::Visibility::Restricted { ref path, .. } => match path.def {
243 // If there is no resolution, `resolve` will have already reported an error, so
244 // assume that the visibility is public to avoid reporting more privacy errors.
245 Def::Err => Visibility::Public,
246 def => Visibility::Restricted(def.def_id()),
249 Visibility::Restricted(tcx.hir.get_module_parent(id))
254 /// Returns true if an item with this visibility is accessible from the given block.
255 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
256 let restriction = match self {
257 // Public items are visible everywhere.
258 Visibility::Public => return true,
259 // Private items from other crates are visible nowhere.
260 Visibility::Invisible => return false,
261 // Restricted items are visible in an arbitrary local module.
262 Visibility::Restricted(other) if other.krate != module.krate => return false,
263 Visibility::Restricted(module) => module,
266 tree.is_descendant_of(module, restriction)
269 /// Returns true if this visibility is at least as accessible as the given visibility
270 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
271 let vis_restriction = match vis {
272 Visibility::Public => return self == Visibility::Public,
273 Visibility::Invisible => return true,
274 Visibility::Restricted(module) => module,
277 self.is_accessible_from(vis_restriction, tree)
281 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
283 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
284 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
285 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
286 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
289 /// The crate variances map is computed during typeck and contains the
290 /// variance of every item in the local crate. You should not use it
291 /// directly, because to do so will make your pass dependent on the
292 /// HIR of every item in the local crate. Instead, use
293 /// `tcx.variances_of()` to get the variance for a *particular*
295 pub struct CrateVariancesMap {
296 /// This relation tracks the dependencies between the variance of
297 /// various items. In particular, if `a < b`, then the variance of
298 /// `a` depends on the sources of `b`.
299 pub dependencies: TransitiveRelation<DefId>,
301 /// For each item with generics, maps to a vector of the variance
302 /// of its generics. If an item has no generics, it will have no
304 pub variances: FxHashMap<DefId, Rc<Vec<ty::Variance>>>,
306 /// An empty vector, useful for cloning.
307 pub empty_variance: Rc<Vec<ty::Variance>>,
311 /// `a.xform(b)` combines the variance of a context with the
312 /// variance of a type with the following meaning. If we are in a
313 /// context with variance `a`, and we encounter a type argument in
314 /// a position with variance `b`, then `a.xform(b)` is the new
315 /// variance with which the argument appears.
321 /// Here, the "ambient" variance starts as covariant. `*mut T` is
322 /// invariant with respect to `T`, so the variance in which the
323 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
324 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
325 /// respect to its type argument `T`, and hence the variance of
326 /// the `i32` here is `Invariant.xform(Covariant)`, which results
327 /// (again) in `Invariant`.
331 /// fn(*const Vec<i32>, *mut Vec<i32)
333 /// The ambient variance is covariant. A `fn` type is
334 /// contravariant with respect to its parameters, so the variance
335 /// within which both pointer types appear is
336 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
337 /// T` is covariant with respect to `T`, so the variance within
338 /// which the first `Vec<i32>` appears is
339 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
340 /// is true for its `i32` argument. In the `*mut T` case, the
341 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
342 /// and hence the outermost type is `Invariant` with respect to
343 /// `Vec<i32>` (and its `i32` argument).
345 /// Source: Figure 1 of "Taming the Wildcards:
346 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
347 pub fn xform(self, v: ty::Variance) -> ty::Variance {
349 // Figure 1, column 1.
350 (ty::Covariant, ty::Covariant) => ty::Covariant,
351 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
352 (ty::Covariant, ty::Invariant) => ty::Invariant,
353 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
355 // Figure 1, column 2.
356 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
357 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
358 (ty::Contravariant, ty::Invariant) => ty::Invariant,
359 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
361 // Figure 1, column 3.
362 (ty::Invariant, _) => ty::Invariant,
364 // Figure 1, column 4.
365 (ty::Bivariant, _) => ty::Bivariant,
370 // Contains information needed to resolve types and (in the future) look up
371 // the types of AST nodes.
372 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
373 pub struct CReaderCacheKey {
378 // Flags that we track on types. These flags are propagated upwards
379 // through the type during type construction, so that we can quickly
380 // check whether the type has various kinds of types in it without
381 // recursing over the type itself.
383 flags TypeFlags: u32 {
384 const HAS_PARAMS = 1 << 0,
385 const HAS_SELF = 1 << 1,
386 const HAS_TY_INFER = 1 << 2,
387 const HAS_RE_INFER = 1 << 3,
388 const HAS_RE_SKOL = 1 << 4,
389 const HAS_RE_EARLY_BOUND = 1 << 5,
390 const HAS_FREE_REGIONS = 1 << 6,
391 const HAS_TY_ERR = 1 << 7,
392 const HAS_PROJECTION = 1 << 8,
393 const HAS_TY_CLOSURE = 1 << 9,
395 // true if there are "names" of types and regions and so forth
396 // that are local to a particular fn
397 const HAS_LOCAL_NAMES = 1 << 10,
399 // Present if the type belongs in a local type context.
400 // Only set for TyInfer other than Fresh.
401 const KEEP_IN_LOCAL_TCX = 1 << 11,
403 // Is there a projection that does not involve a bound region?
404 // Currently we can't normalize projections w/ bound regions.
405 const HAS_NORMALIZABLE_PROJECTION = 1 << 12,
407 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
408 TypeFlags::HAS_SELF.bits |
409 TypeFlags::HAS_RE_EARLY_BOUND.bits,
411 // Flags representing the nominal content of a type,
412 // computed by FlagsComputation. If you add a new nominal
413 // flag, it should be added here too.
414 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
415 TypeFlags::HAS_SELF.bits |
416 TypeFlags::HAS_TY_INFER.bits |
417 TypeFlags::HAS_RE_INFER.bits |
418 TypeFlags::HAS_RE_SKOL.bits |
419 TypeFlags::HAS_RE_EARLY_BOUND.bits |
420 TypeFlags::HAS_FREE_REGIONS.bits |
421 TypeFlags::HAS_TY_ERR.bits |
422 TypeFlags::HAS_PROJECTION.bits |
423 TypeFlags::HAS_TY_CLOSURE.bits |
424 TypeFlags::HAS_LOCAL_NAMES.bits |
425 TypeFlags::KEEP_IN_LOCAL_TCX.bits,
429 pub struct TyS<'tcx> {
430 pub sty: TypeVariants<'tcx>,
431 pub flags: TypeFlags,
433 // the maximal depth of any bound regions appearing in this type.
437 impl<'tcx> PartialEq for TyS<'tcx> {
439 fn eq(&self, other: &TyS<'tcx>) -> bool {
440 // (self as *const _) == (other as *const _)
441 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
444 impl<'tcx> Eq for TyS<'tcx> {}
446 impl<'tcx> Hash for TyS<'tcx> {
447 fn hash<H: Hasher>(&self, s: &mut H) {
448 (self as *const TyS).hash(s)
452 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for ty::TyS<'tcx> {
453 fn hash_stable<W: StableHasherResult>(&self,
454 hcx: &mut StableHashingContext<'a, 'tcx>,
455 hasher: &mut StableHasher<W>) {
459 // The other fields just provide fast access to information that is
460 // also contained in `sty`, so no need to hash them.
465 sty.hash_stable(hcx, hasher);
469 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
471 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
472 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
474 /// A wrapper for slices with the additional invariant
475 /// that the slice is interned and no other slice with
476 /// the same contents can exist in the same context.
477 /// This means we can use pointer + length for both
478 /// equality comparisons and hashing.
479 #[derive(Debug, RustcEncodable)]
480 pub struct Slice<T>([T]);
482 impl<T> PartialEq for Slice<T> {
484 fn eq(&self, other: &Slice<T>) -> bool {
485 (&self.0 as *const [T]) == (&other.0 as *const [T])
488 impl<T> Eq for Slice<T> {}
490 impl<T> Hash for Slice<T> {
491 fn hash<H: Hasher>(&self, s: &mut H) {
492 (self.as_ptr(), self.len()).hash(s)
496 impl<T> Deref for Slice<T> {
498 fn deref(&self) -> &[T] {
503 impl<'a, T> IntoIterator for &'a Slice<T> {
505 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
506 fn into_iter(self) -> Self::IntoIter {
511 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {}
514 pub fn empty<'a>() -> &'a Slice<T> {
516 mem::transmute(slice::from_raw_parts(0x1 as *const T, 0))
521 /// Upvars do not get their own node-id. Instead, we use the pair of
522 /// the original var id (that is, the root variable that is referenced
523 /// by the upvar) and the id of the closure expression.
524 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
527 pub closure_expr_id: NodeId,
530 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
531 pub enum BorrowKind {
532 /// Data must be immutable and is aliasable.
535 /// Data must be immutable but not aliasable. This kind of borrow
536 /// cannot currently be expressed by the user and is used only in
537 /// implicit closure bindings. It is needed when the closure
538 /// is borrowing or mutating a mutable referent, e.g.:
540 /// let x: &mut isize = ...;
541 /// let y = || *x += 5;
543 /// If we were to try to translate this closure into a more explicit
544 /// form, we'd encounter an error with the code as written:
546 /// struct Env { x: & &mut isize }
547 /// let x: &mut isize = ...;
548 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
549 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
551 /// This is then illegal because you cannot mutate a `&mut` found
552 /// in an aliasable location. To solve, you'd have to translate with
553 /// an `&mut` borrow:
555 /// struct Env { x: & &mut isize }
556 /// let x: &mut isize = ...;
557 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
558 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
560 /// Now the assignment to `**env.x` is legal, but creating a
561 /// mutable pointer to `x` is not because `x` is not mutable. We
562 /// could fix this by declaring `x` as `let mut x`. This is ok in
563 /// user code, if awkward, but extra weird for closures, since the
564 /// borrow is hidden.
566 /// So we introduce a "unique imm" borrow -- the referent is
567 /// immutable, but not aliasable. This solves the problem. For
568 /// simplicity, we don't give users the way to express this
569 /// borrow, it's just used when translating closures.
572 /// Data is mutable and not aliasable.
576 /// Information describing the capture of an upvar. This is computed
577 /// during `typeck`, specifically by `regionck`.
578 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
579 pub enum UpvarCapture<'tcx> {
580 /// Upvar is captured by value. This is always true when the
581 /// closure is labeled `move`, but can also be true in other cases
582 /// depending on inference.
585 /// Upvar is captured by reference.
586 ByRef(UpvarBorrow<'tcx>),
589 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
590 pub struct UpvarBorrow<'tcx> {
591 /// The kind of borrow: by-ref upvars have access to shared
592 /// immutable borrows, which are not part of the normal language
594 pub kind: BorrowKind,
596 /// Region of the resulting reference.
597 pub region: ty::Region<'tcx>,
600 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
602 #[derive(Copy, Clone)]
603 pub struct ClosureUpvar<'tcx> {
609 #[derive(Clone, Copy, PartialEq)]
610 pub enum IntVarValue {
612 UintType(ast::UintTy),
615 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
616 pub struct TypeParameterDef {
620 pub has_default: bool,
621 pub object_lifetime_default: ObjectLifetimeDefault,
623 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
624 /// on generic parameter `T`, asserts data behind the parameter
625 /// `T` won't be accessed during the parent type's `Drop` impl.
626 pub pure_wrt_drop: bool,
629 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
630 pub struct RegionParameterDef {
634 pub issue_32330: Option<ty::Issue32330>,
636 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
637 /// on generic parameter `'a`, asserts data of lifetime `'a`
638 /// won't be accessed during the parent type's `Drop` impl.
639 pub pure_wrt_drop: bool,
642 impl RegionParameterDef {
643 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
644 ty::EarlyBoundRegion {
651 pub fn to_bound_region(&self) -> ty::BoundRegion {
652 self.to_early_bound_region_data().to_bound_region()
656 impl ty::EarlyBoundRegion {
657 pub fn to_bound_region(&self) -> ty::BoundRegion {
658 ty::BoundRegion::BrNamed(self.def_id, self.name)
662 /// Information about the formal type/lifetime parameters associated
663 /// with an item or method. Analogous to hir::Generics.
664 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
665 pub struct Generics {
666 pub parent: Option<DefId>,
667 pub parent_regions: u32,
668 pub parent_types: u32,
669 pub regions: Vec<RegionParameterDef>,
670 pub types: Vec<TypeParameterDef>,
672 /// Reverse map to each `TypeParameterDef`'s `index` field, from
673 /// `def_id.index` (`def_id.krate` is the same as the item's).
674 pub type_param_to_index: BTreeMap<DefIndex, u32>,
680 pub fn parent_count(&self) -> usize {
681 self.parent_regions as usize + self.parent_types as usize
684 pub fn own_count(&self) -> usize {
685 self.regions.len() + self.types.len()
688 pub fn count(&self) -> usize {
689 self.parent_count() + self.own_count()
692 pub fn region_param(&self, param: &EarlyBoundRegion) -> &RegionParameterDef {
693 assert_eq!(self.parent_count(), 0);
694 &self.regions[param.index as usize - self.has_self as usize]
697 pub fn type_param(&self, param: &ParamTy) -> &TypeParameterDef {
698 assert_eq!(self.parent_count(), 0);
699 &self.types[param.idx as usize - self.has_self as usize - self.regions.len()]
703 /// Bounds on generics.
704 #[derive(Clone, Default)]
705 pub struct GenericPredicates<'tcx> {
706 pub parent: Option<DefId>,
707 pub predicates: Vec<Predicate<'tcx>>,
710 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
711 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
713 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
714 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
715 -> InstantiatedPredicates<'tcx> {
716 let mut instantiated = InstantiatedPredicates::empty();
717 self.instantiate_into(tcx, &mut instantiated, substs);
720 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
721 -> InstantiatedPredicates<'tcx> {
722 InstantiatedPredicates {
723 predicates: self.predicates.subst(tcx, substs)
727 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
728 instantiated: &mut InstantiatedPredicates<'tcx>,
729 substs: &Substs<'tcx>) {
730 if let Some(def_id) = self.parent {
731 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
733 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
736 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
737 -> InstantiatedPredicates<'tcx> {
738 let mut instantiated = InstantiatedPredicates::empty();
739 self.instantiate_identity_into(tcx, &mut instantiated);
743 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
744 instantiated: &mut InstantiatedPredicates<'tcx>) {
745 if let Some(def_id) = self.parent {
746 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
748 instantiated.predicates.extend(&self.predicates)
751 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
752 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
753 -> InstantiatedPredicates<'tcx>
755 assert_eq!(self.parent, None);
756 InstantiatedPredicates {
757 predicates: self.predicates.iter().map(|pred| {
758 pred.subst_supertrait(tcx, poly_trait_ref)
764 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
765 pub enum Predicate<'tcx> {
766 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
767 /// the `Self` type of the trait reference and `A`, `B`, and `C`
768 /// would be the type parameters.
769 Trait(PolyTraitPredicate<'tcx>),
771 /// where `T1 == T2`.
772 Equate(PolyEquatePredicate<'tcx>),
775 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
778 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
780 /// where <T as TraitRef>::Name == X, approximately.
781 /// See `ProjectionPredicate` struct for details.
782 Projection(PolyProjectionPredicate<'tcx>),
785 WellFormed(Ty<'tcx>),
787 /// trait must be object-safe
790 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
791 /// for some substitutions `...` and T being a closure type.
792 /// Satisfied (or refuted) once we know the closure's kind.
793 ClosureKind(DefId, ClosureKind),
796 Subtype(PolySubtypePredicate<'tcx>),
799 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
800 /// Performs a substitution suitable for going from a
801 /// poly-trait-ref to supertraits that must hold if that
802 /// poly-trait-ref holds. This is slightly different from a normal
803 /// substitution in terms of what happens with bound regions. See
804 /// lengthy comment below for details.
805 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
806 trait_ref: &ty::PolyTraitRef<'tcx>)
807 -> ty::Predicate<'tcx>
809 // The interaction between HRTB and supertraits is not entirely
810 // obvious. Let me walk you (and myself) through an example.
812 // Let's start with an easy case. Consider two traits:
814 // trait Foo<'a> : Bar<'a,'a> { }
815 // trait Bar<'b,'c> { }
817 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
818 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
819 // knew that `Foo<'x>` (for any 'x) then we also know that
820 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
821 // normal substitution.
823 // In terms of why this is sound, the idea is that whenever there
824 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
825 // holds. So if there is an impl of `T:Foo<'a>` that applies to
826 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
829 // Another example to be careful of is this:
831 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
832 // trait Bar1<'b,'c> { }
834 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
835 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
836 // reason is similar to the previous example: any impl of
837 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
838 // basically we would want to collapse the bound lifetimes from
839 // the input (`trait_ref`) and the supertraits.
841 // To achieve this in practice is fairly straightforward. Let's
842 // consider the more complicated scenario:
844 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
845 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
846 // where both `'x` and `'b` would have a DB index of 1.
847 // The substitution from the input trait-ref is therefore going to be
848 // `'a => 'x` (where `'x` has a DB index of 1).
849 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
850 // early-bound parameter and `'b' is a late-bound parameter with a
852 // - If we replace `'a` with `'x` from the input, it too will have
853 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
854 // just as we wanted.
856 // There is only one catch. If we just apply the substitution `'a
857 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
858 // adjust the DB index because we substituting into a binder (it
859 // tries to be so smart...) resulting in `for<'x> for<'b>
860 // Bar1<'x,'b>` (we have no syntax for this, so use your
861 // imagination). Basically the 'x will have DB index of 2 and 'b
862 // will have DB index of 1. Not quite what we want. So we apply
863 // the substitution to the *contents* of the trait reference,
864 // rather than the trait reference itself (put another way, the
865 // substitution code expects equal binding levels in the values
866 // from the substitution and the value being substituted into, and
867 // this trick achieves that).
869 let substs = &trait_ref.0.substs;
871 Predicate::Trait(ty::Binder(ref data)) =>
872 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
873 Predicate::Equate(ty::Binder(ref data)) =>
874 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
875 Predicate::Subtype(ty::Binder(ref data)) =>
876 Predicate::Subtype(ty::Binder(data.subst(tcx, substs))),
877 Predicate::RegionOutlives(ty::Binder(ref data)) =>
878 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
879 Predicate::TypeOutlives(ty::Binder(ref data)) =>
880 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
881 Predicate::Projection(ty::Binder(ref data)) =>
882 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
883 Predicate::WellFormed(data) =>
884 Predicate::WellFormed(data.subst(tcx, substs)),
885 Predicate::ObjectSafe(trait_def_id) =>
886 Predicate::ObjectSafe(trait_def_id),
887 Predicate::ClosureKind(closure_def_id, kind) =>
888 Predicate::ClosureKind(closure_def_id, kind),
893 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
894 pub struct TraitPredicate<'tcx> {
895 pub trait_ref: TraitRef<'tcx>
897 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
899 impl<'tcx> TraitPredicate<'tcx> {
900 pub fn def_id(&self) -> DefId {
901 self.trait_ref.def_id
904 /// Creates the dep-node for selecting/evaluating this trait reference.
905 fn dep_node(&self) -> DepNode<DefId> {
906 // Extact the trait-def and first def-id from inputs. See the
907 // docs for `DepNode::TraitSelect` for more information.
908 let trait_def_id = self.def_id();
911 .flat_map(|t| t.walk())
912 .filter_map(|t| match t.sty {
913 ty::TyAdt(adt_def, _) => Some(adt_def.did),
917 .unwrap_or(trait_def_id);
918 DepNode::TraitSelect {
919 trait_def_id: trait_def_id,
920 input_def_id: input_def_id
924 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
925 self.trait_ref.input_types()
928 pub fn self_ty(&self) -> Ty<'tcx> {
929 self.trait_ref.self_ty()
933 impl<'tcx> PolyTraitPredicate<'tcx> {
934 pub fn def_id(&self) -> DefId {
935 // ok to skip binder since trait def-id does not care about regions
939 pub fn dep_node(&self) -> DepNode<DefId> {
940 // ok to skip binder since depnode does not care about regions
945 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
946 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
947 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
949 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
950 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
951 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
952 pub type PolyRegionOutlivesPredicate<'tcx> = PolyOutlivesPredicate<ty::Region<'tcx>,
954 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
956 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
957 pub struct SubtypePredicate<'tcx> {
958 pub a_is_expected: bool,
962 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
964 /// This kind of predicate has no *direct* correspondent in the
965 /// syntax, but it roughly corresponds to the syntactic forms:
967 /// 1. `T : TraitRef<..., Item=Type>`
968 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
970 /// In particular, form #1 is "desugared" to the combination of a
971 /// normal trait predicate (`T : TraitRef<...>`) and one of these
972 /// predicates. Form #2 is a broader form in that it also permits
973 /// equality between arbitrary types. Processing an instance of Form
974 /// #2 eventually yields one of these `ProjectionPredicate`
975 /// instances to normalize the LHS.
976 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
977 pub struct ProjectionPredicate<'tcx> {
978 pub projection_ty: ProjectionTy<'tcx>,
982 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
984 impl<'tcx> PolyProjectionPredicate<'tcx> {
985 pub fn item_name(&self, tcx: TyCtxt) -> Name {
986 self.0.projection_ty.item_name(tcx) // safe to skip the binder to access a name
990 pub trait ToPolyTraitRef<'tcx> {
991 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
994 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
995 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
996 assert!(!self.has_escaping_regions());
997 ty::Binder(self.clone())
1001 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1002 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1003 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1007 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
1008 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1009 // Note: unlike with TraitRef::to_poly_trait_ref(),
1010 // self.0.trait_ref is permitted to have escaping regions.
1011 // This is because here `self` has a `Binder` and so does our
1012 // return value, so we are preserving the number of binding
1014 ty::Binder(self.0.projection_ty.trait_ref)
1018 pub trait ToPredicate<'tcx> {
1019 fn to_predicate(&self) -> Predicate<'tcx>;
1022 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1023 fn to_predicate(&self) -> Predicate<'tcx> {
1024 // we're about to add a binder, so let's check that we don't
1025 // accidentally capture anything, or else that might be some
1026 // weird debruijn accounting.
1027 assert!(!self.has_escaping_regions());
1029 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
1030 trait_ref: self.clone()
1035 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1036 fn to_predicate(&self) -> Predicate<'tcx> {
1037 ty::Predicate::Trait(self.to_poly_trait_predicate())
1041 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
1042 fn to_predicate(&self) -> Predicate<'tcx> {
1043 Predicate::Equate(self.clone())
1047 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1048 fn to_predicate(&self) -> Predicate<'tcx> {
1049 Predicate::RegionOutlives(self.clone())
1053 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1054 fn to_predicate(&self) -> Predicate<'tcx> {
1055 Predicate::TypeOutlives(self.clone())
1059 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1060 fn to_predicate(&self) -> Predicate<'tcx> {
1061 Predicate::Projection(self.clone())
1065 impl<'tcx> Predicate<'tcx> {
1066 /// Iterates over the types in this predicate. Note that in all
1067 /// cases this is skipping over a binder, so late-bound regions
1068 /// with depth 0 are bound by the predicate.
1069 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1070 let vec: Vec<_> = match *self {
1071 ty::Predicate::Trait(ref data) => {
1072 data.skip_binder().input_types().collect()
1074 ty::Predicate::Equate(ty::Binder(ref data)) => {
1075 vec![data.0, data.1]
1077 ty::Predicate::Subtype(ty::Binder(SubtypePredicate { a, b, a_is_expected: _ })) => {
1080 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
1083 ty::Predicate::RegionOutlives(..) => {
1086 ty::Predicate::Projection(ref data) => {
1087 let trait_inputs = data.0.projection_ty.trait_ref.input_types();
1088 trait_inputs.chain(Some(data.0.ty)).collect()
1090 ty::Predicate::WellFormed(data) => {
1093 ty::Predicate::ObjectSafe(_trait_def_id) => {
1096 ty::Predicate::ClosureKind(_closure_def_id, _kind) => {
1101 // The only reason to collect into a vector here is that I was
1102 // too lazy to make the full (somewhat complicated) iterator
1103 // type that would be needed here. But I wanted this fn to
1104 // return an iterator conceptually, rather than a `Vec`, so as
1105 // to be closer to `Ty::walk`.
1109 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1111 Predicate::Trait(ref t) => {
1112 Some(t.to_poly_trait_ref())
1114 Predicate::Projection(..) |
1115 Predicate::Equate(..) |
1116 Predicate::Subtype(..) |
1117 Predicate::RegionOutlives(..) |
1118 Predicate::WellFormed(..) |
1119 Predicate::ObjectSafe(..) |
1120 Predicate::ClosureKind(..) |
1121 Predicate::TypeOutlives(..) => {
1128 /// Represents the bounds declared on a particular set of type
1129 /// parameters. Should eventually be generalized into a flag list of
1130 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1131 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1132 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1133 /// the `GenericPredicates` are expressed in terms of the bound type
1134 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1135 /// represented a set of bounds for some particular instantiation,
1136 /// meaning that the generic parameters have been substituted with
1141 /// struct Foo<T,U:Bar<T>> { ... }
1143 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1144 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1145 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1146 /// [usize:Bar<isize>]]`.
1148 pub struct InstantiatedPredicates<'tcx> {
1149 pub predicates: Vec<Predicate<'tcx>>,
1152 impl<'tcx> InstantiatedPredicates<'tcx> {
1153 pub fn empty() -> InstantiatedPredicates<'tcx> {
1154 InstantiatedPredicates { predicates: vec![] }
1157 pub fn is_empty(&self) -> bool {
1158 self.predicates.is_empty()
1162 /// When type checking, we use the `ParamEnv` to track
1163 /// details about the set of where-clauses that are in scope at this
1164 /// particular point.
1165 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1166 pub struct ParamEnv<'tcx> {
1167 /// Obligations that the caller must satisfy. This is basically
1168 /// the set of bounds on the in-scope type parameters, translated
1169 /// into Obligations, and elaborated and normalized.
1170 pub caller_bounds: &'tcx Slice<ty::Predicate<'tcx>>,
1172 /// Typically, this is `Reveal::UserFacing`, but during trans we
1173 /// want `Reveal::All` -- note that this is always paired with an
1174 /// empty environment. To get that, use `ParamEnv::reveal()`.
1175 pub reveal: traits::Reveal,
1178 impl<'tcx> ParamEnv<'tcx> {
1179 /// Creates a suitable environment in which to perform trait
1180 /// queries on the given value. This will either be `self` *or*
1181 /// the empty environment, depending on whether `value` references
1182 /// type parameters that are in scope. (If it doesn't, then any
1183 /// judgements should be completely independent of the context,
1184 /// and hence we can safely use the empty environment so as to
1185 /// enable more sharing across functions.)
1187 /// NB: This is a mildly dubious thing to do, in that a function
1188 /// (or other environment) might have wacky where-clauses like
1189 /// `where Box<u32>: Copy`, which are clearly never
1190 /// satisfiable. The code will at present ignore these,
1191 /// effectively, when type-checking the body of said
1192 /// function. This preserves existing behavior in any
1193 /// case. --nmatsakis
1194 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1195 assert!(!value.needs_infer());
1196 if value.has_param_types() || value.has_self_ty() {
1203 param_env: ParamEnv::empty(self.reveal),
1210 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1211 pub struct ParamEnvAnd<'tcx, T> {
1212 pub param_env: ParamEnv<'tcx>,
1216 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1217 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1218 (self.param_env, self.value)
1222 #[derive(Copy, Clone, Debug)]
1223 pub struct Destructor {
1224 /// The def-id of the destructor method
1229 flags AdtFlags: u32 {
1230 const NO_ADT_FLAGS = 0,
1231 const IS_ENUM = 1 << 0,
1232 const IS_PHANTOM_DATA = 1 << 1,
1233 const IS_FUNDAMENTAL = 1 << 2,
1234 const IS_UNION = 1 << 3,
1235 const IS_BOX = 1 << 4,
1240 pub struct VariantDef {
1241 /// The variant's DefId. If this is a tuple-like struct,
1242 /// this is the DefId of the struct's ctor.
1244 pub name: Name, // struct's name if this is a struct
1245 pub discr: VariantDiscr,
1246 pub fields: Vec<FieldDef>,
1247 pub ctor_kind: CtorKind,
1250 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1251 pub enum VariantDiscr {
1252 /// Explicit value for this variant, i.e. `X = 123`.
1253 /// The `DefId` corresponds to the embedded constant.
1256 /// The previous variant's discriminant plus one.
1257 /// For efficiency reasons, the distance from the
1258 /// last `Explicit` discriminant is being stored,
1259 /// or `0` for the first variant, if it has none.
1264 pub struct FieldDef {
1267 pub vis: Visibility,
1270 /// The definition of an abstract data type - a struct or enum.
1272 /// These are all interned (by intern_adt_def) into the adt_defs
1276 pub variants: Vec<VariantDef>,
1278 pub repr: ReprOptions,
1281 impl PartialEq for AdtDef {
1282 // AdtDef are always interned and this is part of TyS equality
1284 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1287 impl Eq for AdtDef {}
1289 impl Hash for AdtDef {
1291 fn hash<H: Hasher>(&self, s: &mut H) {
1292 (self as *const AdtDef).hash(s)
1296 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1297 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1302 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1305 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for AdtDef {
1306 fn hash_stable<W: StableHasherResult>(&self,
1307 hcx: &mut StableHashingContext<'a, 'tcx>,
1308 hasher: &mut StableHasher<W>) {
1316 did.hash_stable(hcx, hasher);
1317 variants.hash_stable(hcx, hasher);
1318 flags.hash_stable(hcx, hasher);
1319 repr.hash_stable(hcx, hasher);
1323 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1324 pub enum AdtKind { Struct, Union, Enum }
1327 #[derive(RustcEncodable, RustcDecodable, Default)]
1328 flags ReprFlags: u8 {
1329 const IS_C = 1 << 0,
1330 const IS_PACKED = 1 << 1,
1331 const IS_SIMD = 1 << 2,
1332 // Internal only for now. If true, don't reorder fields.
1333 const IS_LINEAR = 1 << 3,
1335 // Any of these flags being set prevent field reordering optimisation.
1336 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1337 ReprFlags::IS_PACKED.bits |
1338 ReprFlags::IS_SIMD.bits |
1339 ReprFlags::IS_LINEAR.bits,
1343 impl_stable_hash_for!(struct ReprFlags {
1349 /// Represents the repr options provided by the user,
1350 #[derive(Copy, Clone, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1351 pub struct ReprOptions {
1352 pub int: Option<attr::IntType>,
1354 pub flags: ReprFlags,
1357 impl_stable_hash_for!(struct ReprOptions {
1364 pub fn new(tcx: TyCtxt, did: DefId) -> ReprOptions {
1365 let mut flags = ReprFlags::empty();
1366 let mut size = None;
1367 let mut max_align = 0;
1368 for attr in tcx.get_attrs(did).iter() {
1369 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1370 flags.insert(match r {
1371 attr::ReprExtern => ReprFlags::IS_C,
1372 attr::ReprPacked => ReprFlags::IS_PACKED,
1373 attr::ReprSimd => ReprFlags::IS_SIMD,
1374 attr::ReprInt(i) => {
1378 attr::ReprAlign(align) => {
1379 max_align = cmp::max(align, max_align);
1386 // FIXME(eddyb) This is deprecated and should be removed.
1387 if tcx.has_attr(did, "simd") {
1388 flags.insert(ReprFlags::IS_SIMD);
1391 // This is here instead of layout because the choice must make it into metadata.
1392 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1393 flags.insert(ReprFlags::IS_LINEAR);
1395 ReprOptions { int: size, align: max_align, flags: flags }
1399 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1401 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1403 pub fn packed(&self) -> bool { self.flags.contains(ReprFlags::IS_PACKED) }
1405 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1407 pub fn discr_type(&self) -> attr::IntType {
1408 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Is))
1411 /// Returns true if this `#[repr()]` should inhabit "smart enum
1412 /// layout" optimizations, such as representing `Foo<&T>` as a
1414 pub fn inhibit_enum_layout_opt(&self) -> bool {
1415 self.c() || self.int.is_some()
1419 impl<'a, 'gcx, 'tcx> AdtDef {
1423 variants: Vec<VariantDef>,
1424 repr: ReprOptions) -> Self {
1425 let mut flags = AdtFlags::NO_ADT_FLAGS;
1426 let attrs = tcx.get_attrs(did);
1427 if attr::contains_name(&attrs, "fundamental") {
1428 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1430 if Some(did) == tcx.lang_items.phantom_data() {
1431 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1433 if Some(did) == tcx.lang_items.owned_box() {
1434 flags = flags | AdtFlags::IS_BOX;
1437 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
1438 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
1439 AdtKind::Struct => {}
1450 pub fn is_struct(&self) -> bool {
1451 !self.is_union() && !self.is_enum()
1455 pub fn is_union(&self) -> bool {
1456 self.flags.intersects(AdtFlags::IS_UNION)
1460 pub fn is_enum(&self) -> bool {
1461 self.flags.intersects(AdtFlags::IS_ENUM)
1464 /// Returns the kind of the ADT - Struct or Enum.
1466 pub fn adt_kind(&self) -> AdtKind {
1469 } else if self.is_union() {
1476 pub fn descr(&self) -> &'static str {
1477 match self.adt_kind() {
1478 AdtKind::Struct => "struct",
1479 AdtKind::Union => "union",
1480 AdtKind::Enum => "enum",
1484 pub fn variant_descr(&self) -> &'static str {
1485 match self.adt_kind() {
1486 AdtKind::Struct => "struct",
1487 AdtKind::Union => "union",
1488 AdtKind::Enum => "variant",
1492 /// Returns whether this type is #[fundamental] for the purposes
1493 /// of coherence checking.
1495 pub fn is_fundamental(&self) -> bool {
1496 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
1499 /// Returns true if this is PhantomData<T>.
1501 pub fn is_phantom_data(&self) -> bool {
1502 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
1505 /// Returns true if this is Box<T>.
1507 pub fn is_box(&self) -> bool {
1508 self.flags.intersects(AdtFlags::IS_BOX)
1511 /// Returns whether this type has a destructor.
1512 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
1513 self.destructor(tcx).is_some()
1516 /// Asserts this is a struct and returns the struct's unique
1518 pub fn struct_variant(&self) -> &VariantDef {
1519 assert!(!self.is_enum());
1524 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
1525 tcx.predicates_of(self.did)
1528 /// Returns an iterator over all fields contained
1531 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
1532 self.variants.iter().flat_map(|v| v.fields.iter())
1536 pub fn is_univariant(&self) -> bool {
1537 self.variants.len() == 1
1540 pub fn is_payloadfree(&self) -> bool {
1541 !self.variants.is_empty() &&
1542 self.variants.iter().all(|v| v.fields.is_empty())
1545 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
1548 .find(|v| v.did == vid)
1549 .expect("variant_with_id: unknown variant")
1552 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1555 .position(|v| v.did == vid)
1556 .expect("variant_index_with_id: unknown variant")
1559 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
1561 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
1562 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
1563 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.struct_variant(),
1564 _ => bug!("unexpected def {:?} in variant_of_def", def)
1569 pub fn discriminants(&'a self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1570 -> impl Iterator<Item=ConstInt> + 'a {
1571 let repr_type = self.repr.discr_type();
1572 let initial = repr_type.initial_discriminant(tcx.global_tcx());
1573 let mut prev_discr = None::<ConstInt>;
1574 self.variants.iter().map(move |v| {
1575 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr());
1576 if let VariantDiscr::Explicit(expr_did) = v.discr {
1577 let substs = Substs::empty();
1578 match tcx.const_eval((expr_did, substs)) {
1579 Ok(ConstVal::Integral(v)) => {
1583 if !expr_did.is_local() {
1584 span_bug!(tcx.def_span(expr_did),
1585 "variant discriminant evaluation succeeded \
1586 in its crate but failed locally: {:?}", err);
1591 prev_discr = Some(discr);
1597 /// Compute the discriminant value used by a specific variant.
1598 /// Unlike `discriminants`, this is (amortized) constant-time,
1599 /// only doing at most one query for evaluating an explicit
1600 /// discriminant (the last one before the requested variant),
1601 /// assuming there are no constant-evaluation errors there.
1602 pub fn discriminant_for_variant(&self,
1603 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1604 variant_index: usize)
1606 let repr_type = self.repr.discr_type();
1607 let mut explicit_value = repr_type.initial_discriminant(tcx.global_tcx());
1608 let mut explicit_index = variant_index;
1610 match self.variants[explicit_index].discr {
1611 ty::VariantDiscr::Relative(0) => break,
1612 ty::VariantDiscr::Relative(distance) => {
1613 explicit_index -= distance;
1615 ty::VariantDiscr::Explicit(expr_did) => {
1616 let substs = Substs::empty();
1617 match tcx.const_eval((expr_did, substs)) {
1618 Ok(ConstVal::Integral(v)) => {
1623 if !expr_did.is_local() {
1624 span_bug!(tcx.def_span(expr_did),
1625 "variant discriminant evaluation succeeded \
1626 in its crate but failed locally: {:?}", err);
1628 if explicit_index == 0 {
1631 explicit_index -= 1;
1637 let discr = explicit_value.to_u128_unchecked()
1638 .wrapping_add((variant_index - explicit_index) as u128);
1640 attr::UnsignedInt(ty) => {
1641 ConstInt::new_unsigned_truncating(discr, ty,
1642 tcx.sess.target.uint_type)
1644 attr::SignedInt(ty) => {
1645 ConstInt::new_signed_truncating(discr as i128, ty,
1646 tcx.sess.target.int_type)
1651 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
1652 tcx.adt_destructor(self.did)
1655 /// Returns a list of types such that `Self: Sized` if and only
1656 /// if that type is Sized, or `TyErr` if this type is recursive.
1658 /// Oddly enough, checking that the sized-constraint is Sized is
1659 /// actually more expressive than checking all members:
1660 /// the Sized trait is inductive, so an associated type that references
1661 /// Self would prevent its containing ADT from being Sized.
1663 /// Due to normalization being eager, this applies even if
1664 /// the associated type is behind a pointer, e.g. issue #31299.
1665 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
1666 match queries::adt_sized_constraint::try_get(tcx, DUMMY_SP, self.did) {
1669 debug!("adt_sized_constraint: {:?} is recursive", self);
1670 // This should be reported as an error by `check_representable`.
1672 // Consider the type as Sized in the meanwhile to avoid
1674 tcx.intern_type_list(&[tcx.types.err])
1679 fn sized_constraint_for_ty(&self,
1680 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1683 let result = match ty.sty {
1684 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
1685 TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
1686 TyArray(..) | TyClosure(..) | TyNever => {
1690 TyStr | TyDynamic(..) | TySlice(_) | TyError => {
1691 // these are never sized - return the target type
1695 TyTuple(ref tys, _) => {
1698 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
1702 TyAdt(adt, substs) => {
1704 let adt_tys = adt.sized_constraint(tcx);
1705 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
1708 .map(|ty| ty.subst(tcx, substs))
1709 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
1713 TyProjection(..) | TyAnon(..) => {
1714 // must calculate explicitly.
1715 // FIXME: consider special-casing always-Sized projections
1720 // perf hack: if there is a `T: Sized` bound, then
1721 // we know that `T` is Sized and do not need to check
1724 let sized_trait = match tcx.lang_items.sized_trait() {
1726 _ => return vec![ty]
1728 let sized_predicate = Binder(TraitRef {
1729 def_id: sized_trait,
1730 substs: tcx.mk_substs_trait(ty, &[])
1732 let predicates = tcx.predicates_of(self.did).predicates;
1733 if predicates.into_iter().any(|p| p == sized_predicate) {
1741 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
1745 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
1750 impl<'a, 'gcx, 'tcx> VariantDef {
1752 pub fn find_field_named(&self, name: ast::Name) -> Option<&FieldDef> {
1753 self.index_of_field_named(name).map(|index| &self.fields[index])
1756 pub fn index_of_field_named(&self, name: ast::Name) -> Option<usize> {
1757 if let Some(index) = self.fields.iter().position(|f| f.name == name) {
1760 let mut ident = name.to_ident();
1761 while ident.ctxt != SyntaxContext::empty() {
1762 ident.ctxt.remove_mark();
1763 if let Some(field) = self.fields.iter().position(|f| f.name.to_ident() == ident) {
1771 pub fn field_named(&self, name: ast::Name) -> &FieldDef {
1772 self.find_field_named(name).unwrap()
1776 impl<'a, 'gcx, 'tcx> FieldDef {
1777 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1778 tcx.type_of(self.did).subst(tcx, subst)
1782 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1783 pub enum ClosureKind {
1784 // Warning: Ordering is significant here! The ordering is chosen
1785 // because the trait Fn is a subtrait of FnMut and so in turn, and
1786 // hence we order it so that Fn < FnMut < FnOnce.
1792 impl<'a, 'tcx> ClosureKind {
1793 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
1795 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
1796 ClosureKind::FnMut => {
1797 tcx.require_lang_item(FnMutTraitLangItem)
1799 ClosureKind::FnOnce => {
1800 tcx.require_lang_item(FnOnceTraitLangItem)
1805 /// True if this a type that impls this closure kind
1806 /// must also implement `other`.
1807 pub fn extends(self, other: ty::ClosureKind) -> bool {
1808 match (self, other) {
1809 (ClosureKind::Fn, ClosureKind::Fn) => true,
1810 (ClosureKind::Fn, ClosureKind::FnMut) => true,
1811 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
1812 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
1813 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
1814 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
1820 impl<'tcx> TyS<'tcx> {
1821 /// Iterator that walks `self` and any types reachable from
1822 /// `self`, in depth-first order. Note that just walks the types
1823 /// that appear in `self`, it does not descend into the fields of
1824 /// structs or variants. For example:
1827 /// isize => { isize }
1828 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
1829 /// [isize] => { [isize], isize }
1831 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
1832 TypeWalker::new(self)
1835 /// Iterator that walks the immediate children of `self`. Hence
1836 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
1837 /// (but not `i32`, like `walk`).
1838 pub fn walk_shallow(&'tcx self) -> AccIntoIter<walk::TypeWalkerArray<'tcx>> {
1839 walk::walk_shallow(self)
1842 /// Walks `ty` and any types appearing within `ty`, invoking the
1843 /// callback `f` on each type. If the callback returns false, then the
1844 /// children of the current type are ignored.
1846 /// Note: prefer `ty.walk()` where possible.
1847 pub fn maybe_walk<F>(&'tcx self, mut f: F)
1848 where F : FnMut(Ty<'tcx>) -> bool
1850 let mut walker = self.walk();
1851 while let Some(ty) = walker.next() {
1853 walker.skip_current_subtree();
1859 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1860 pub enum LvaluePreference {
1865 impl LvaluePreference {
1866 pub fn from_mutbl(m: hir::Mutability) -> Self {
1868 hir::MutMutable => PreferMutLvalue,
1869 hir::MutImmutable => NoPreference,
1875 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
1877 hir::MutMutable => MutBorrow,
1878 hir::MutImmutable => ImmBorrow,
1882 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
1883 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
1884 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
1886 pub fn to_mutbl_lossy(self) -> hir::Mutability {
1888 MutBorrow => hir::MutMutable,
1889 ImmBorrow => hir::MutImmutable,
1891 // We have no type corresponding to a unique imm borrow, so
1892 // use `&mut`. It gives all the capabilities of an `&uniq`
1893 // and hence is a safe "over approximation".
1894 UniqueImmBorrow => hir::MutMutable,
1898 pub fn to_user_str(&self) -> &'static str {
1900 MutBorrow => "mutable",
1901 ImmBorrow => "immutable",
1902 UniqueImmBorrow => "uniquely immutable",
1907 #[derive(Debug, Clone)]
1908 pub enum Attributes<'gcx> {
1909 Owned(Rc<[ast::Attribute]>),
1910 Borrowed(&'gcx [ast::Attribute])
1913 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
1914 type Target = [ast::Attribute];
1916 fn deref(&self) -> &[ast::Attribute] {
1918 &Attributes::Owned(ref data) => &data,
1919 &Attributes::Borrowed(data) => data
1924 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
1925 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
1926 self.typeck_tables_of(self.hir.body_owner_def_id(body))
1929 /// Returns an iterator of the def-ids for all body-owners in this
1930 /// crate. If you would prefer to iterate over the bodies
1931 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
1932 pub fn body_owners(self) -> impl Iterator<Item = DefId> + 'a {
1936 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
1939 pub fn expr_span(self, id: NodeId) -> Span {
1940 match self.hir.find(id) {
1941 Some(hir_map::NodeExpr(e)) => {
1945 bug!("Node id {} is not an expr: {:?}", id, f);
1948 bug!("Node id {} is not present in the node map", id);
1953 pub fn local_var_name_str(self, id: NodeId) -> InternedString {
1954 match self.hir.find(id) {
1955 Some(hir_map::NodeLocal(pat)) => {
1957 hir::PatKind::Binding(_, _, ref path1, _) => path1.node.as_str(),
1959 bug!("Variable id {} maps to {:?}, not local", id, pat);
1963 r => bug!("Variable id {} maps to {:?}, not local", id, r),
1967 pub fn expr_is_lval(self, expr: &hir::Expr) -> bool {
1969 hir::ExprPath(hir::QPath::Resolved(_, ref path)) => {
1971 Def::Local(..) | Def::Upvar(..) | Def::Static(..) | Def::Err => true,
1976 hir::ExprType(ref e, _) => {
1977 self.expr_is_lval(e)
1980 hir::ExprUnary(hir::UnDeref, _) |
1981 hir::ExprField(..) |
1982 hir::ExprTupField(..) |
1983 hir::ExprIndex(..) => {
1987 // Partially qualified paths in expressions can only legally
1988 // refer to associated items which are always rvalues.
1989 hir::ExprPath(hir::QPath::TypeRelative(..)) |
1992 hir::ExprMethodCall(..) |
1993 hir::ExprStruct(..) |
1996 hir::ExprMatch(..) |
1997 hir::ExprClosure(..) |
1998 hir::ExprBlock(..) |
1999 hir::ExprRepeat(..) |
2000 hir::ExprArray(..) |
2001 hir::ExprBreak(..) |
2002 hir::ExprAgain(..) |
2004 hir::ExprWhile(..) |
2006 hir::ExprAssign(..) |
2007 hir::ExprInlineAsm(..) |
2008 hir::ExprAssignOp(..) |
2010 hir::ExprUnary(..) |
2012 hir::ExprAddrOf(..) |
2013 hir::ExprBinary(..) |
2014 hir::ExprCast(..) => {
2020 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2021 self.associated_items(id)
2022 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2026 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2027 self.associated_items(did).any(|item| {
2028 item.relevant_for_never()
2032 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2033 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2034 match self.hir.get(node_id) {
2035 hir_map::NodeTraitItem(_) | hir_map::NodeImplItem(_) => true,
2039 match self.describe_def(def_id).expect("no def for def-id") {
2040 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2045 if is_associated_item {
2046 Some(self.associated_item(def_id))
2052 fn associated_item_from_trait_item_ref(self,
2053 parent_def_id: DefId,
2054 parent_vis: &hir::Visibility,
2055 trait_item_ref: &hir::TraitItemRef)
2057 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2058 let (kind, has_self) = match trait_item_ref.kind {
2059 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2060 hir::AssociatedItemKind::Method { has_self } => {
2061 (ty::AssociatedKind::Method, has_self)
2063 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2067 name: trait_item_ref.name,
2069 // Visibility of trait items is inherited from their traits.
2070 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2071 defaultness: trait_item_ref.defaultness,
2073 container: TraitContainer(parent_def_id),
2074 method_has_self_argument: has_self
2078 fn associated_item_from_impl_item_ref(self,
2079 parent_def_id: DefId,
2080 impl_item_ref: &hir::ImplItemRef)
2082 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2083 let (kind, has_self) = match impl_item_ref.kind {
2084 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2085 hir::AssociatedItemKind::Method { has_self } => {
2086 (ty::AssociatedKind::Method, has_self)
2088 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2091 ty::AssociatedItem {
2092 name: impl_item_ref.name,
2094 // Visibility of trait impl items doesn't matter.
2095 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2096 defaultness: impl_item_ref.defaultness,
2098 container: ImplContainer(parent_def_id),
2099 method_has_self_argument: has_self
2103 #[inline] // FIXME(#35870) Avoid closures being unexported due to impl Trait.
2104 pub fn associated_items(self, def_id: DefId)
2105 -> impl Iterator<Item = ty::AssociatedItem> + 'a {
2106 let def_ids = self.associated_item_def_ids(def_id);
2107 (0..def_ids.len()).map(move |i| self.associated_item(def_ids[i]))
2110 /// Returns true if the impls are the same polarity and are implementing
2111 /// a trait which contains no items
2112 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2113 if !self.sess.features.borrow().overlapping_marker_traits {
2116 let trait1_is_empty = self.impl_trait_ref(def_id1)
2117 .map_or(false, |trait_ref| {
2118 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2120 let trait2_is_empty = self.impl_trait_ref(def_id2)
2121 .map_or(false, |trait_ref| {
2122 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2124 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2129 // Returns `ty::VariantDef` if `def` refers to a struct,
2130 // or variant or their constructors, panics otherwise.
2131 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2133 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2134 let enum_did = self.parent_def_id(did).unwrap();
2135 self.adt_def(enum_did).variant_with_id(did)
2137 Def::Struct(did) | Def::Union(did) => {
2138 self.adt_def(did).struct_variant()
2140 Def::StructCtor(ctor_did, ..) => {
2141 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2142 self.adt_def(did).struct_variant()
2144 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2148 pub fn def_key(self, id: DefId) -> hir_map::DefKey {
2150 self.hir.def_key(id)
2152 self.sess.cstore.def_key(id)
2156 /// Convert a `DefId` into its fully expanded `DefPath` (every
2157 /// `DefId` is really just an interned def-path).
2159 /// Note that if `id` is not local to this crate, the result will
2160 /// be a non-local `DefPath`.
2161 pub fn def_path(self, id: DefId) -> hir_map::DefPath {
2163 self.hir.def_path(id)
2165 self.sess.cstore.def_path(id)
2170 pub fn def_path_hash(self, def_id: DefId) -> hir_map::DefPathHash {
2171 if def_id.is_local() {
2172 self.hir.definitions().def_path_hash(def_id.index)
2174 self.sess.cstore.def_path_hash(def_id)
2178 pub fn item_name(self, id: DefId) -> ast::Name {
2179 if let Some(id) = self.hir.as_local_node_id(id) {
2181 } else if id.index == CRATE_DEF_INDEX {
2182 self.sess.cstore.original_crate_name(id.krate)
2184 let def_key = self.sess.cstore.def_key(id);
2185 // The name of a StructCtor is that of its struct parent.
2186 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2187 self.item_name(DefId {
2189 index: def_key.parent.unwrap()
2192 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2193 bug!("item_name: no name for {:?}", self.def_path(id));
2199 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2200 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2204 ty::InstanceDef::Item(did) => {
2205 self.optimized_mir(did)
2207 ty::InstanceDef::Intrinsic(..) |
2208 ty::InstanceDef::FnPtrShim(..) |
2209 ty::InstanceDef::Virtual(..) |
2210 ty::InstanceDef::ClosureOnceShim { .. } |
2211 ty::InstanceDef::DropGlue(..) => {
2212 self.mir_shims(instance)
2217 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2218 /// Returns None if there is no MIR for the DefId
2219 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2220 if self.is_mir_available(did) {
2221 Some(self.optimized_mir(did))
2227 /// Get the attributes of a definition.
2228 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2229 if let Some(id) = self.hir.as_local_node_id(did) {
2230 Attributes::Borrowed(self.hir.attrs(id))
2232 Attributes::Owned(self.item_attrs(did))
2236 /// Determine whether an item is annotated with an attribute
2237 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2238 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2241 pub fn trait_has_default_impl(self, trait_def_id: DefId) -> bool {
2242 self.trait_def(trait_def_id).has_default_impl
2245 /// Given the def_id of an impl, return the def_id of the trait it implements.
2246 /// If it implements no trait, return `None`.
2247 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2248 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2251 /// If the given def ID describes a method belonging to an impl, return the
2252 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2253 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2254 let item = if def_id.krate != LOCAL_CRATE {
2255 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2256 Some(self.associated_item(def_id))
2261 self.opt_associated_item(def_id)
2265 Some(trait_item) => {
2266 match trait_item.container {
2267 TraitContainer(_) => None,
2268 ImplContainer(def_id) => Some(def_id),
2275 pub fn node_scope_region(self, id: NodeId) -> Region<'tcx> {
2276 self.mk_region(ty::ReScope(CodeExtent::Misc(id)))
2279 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2280 /// with the name of the crate containing the impl.
2281 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2282 if impl_did.is_local() {
2283 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2284 Ok(self.hir.span(node_id))
2286 Err(self.sess.cstore.crate_name(impl_did.krate))
2290 pub fn adjust(self, name: Name, scope: DefId, block: NodeId) -> (Ident, DefId) {
2291 self.adjust_ident(name.to_ident(), scope, block)
2294 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
2295 let expansion = match scope.krate {
2296 LOCAL_CRATE => self.hir.definitions().expansion(scope.index),
2299 let scope = match ident.ctxt.adjust(expansion) {
2300 Some(macro_def) => self.hir.definitions().macro_def_scope(macro_def),
2301 None => self.hir.get_module_parent(block),
2307 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2308 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2309 F: FnOnce(&[hir::Freevar]) -> T,
2311 match self.freevars.borrow().get(&fid) {
2313 Some(d) => f(&d[..])
2318 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
2321 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2322 let parent_id = tcx.hir.get_parent(id);
2323 let parent_def_id = tcx.hir.local_def_id(parent_id);
2324 let parent_item = tcx.hir.expect_item(parent_id);
2325 match parent_item.node {
2326 hir::ItemImpl(.., ref impl_item_refs) => {
2327 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2328 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2330 debug_assert_eq!(assoc_item.def_id, def_id);
2335 hir::ItemTrait(.., ref trait_item_refs) => {
2336 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2337 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2340 debug_assert_eq!(assoc_item.def_id, def_id);
2348 span_bug!(parent_item.span,
2349 "unexpected parent of trait or impl item or item not found: {:?}",
2353 /// Calculates the Sized-constraint.
2355 /// In fact, there are only a few options for the types in the constraint:
2356 /// - an obviously-unsized type
2357 /// - a type parameter or projection whose Sizedness can't be known
2358 /// - a tuple of type parameters or projections, if there are multiple
2360 /// - a TyError, if a type contained itself. The representability
2361 /// check should catch this case.
2362 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2364 -> &'tcx [Ty<'tcx>] {
2365 let def = tcx.adt_def(def_id);
2367 let result = tcx.intern_type_list(&def.variants.iter().flat_map(|v| {
2370 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2371 }).collect::<Vec<_>>());
2373 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2378 /// Calculates the dtorck constraint for a type.
2379 fn adt_dtorck_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2381 -> DtorckConstraint<'tcx> {
2382 let def = tcx.adt_def(def_id);
2383 let span = tcx.def_span(def_id);
2384 debug!("dtorck_constraint: {:?}", def);
2386 if def.is_phantom_data() {
2387 let result = DtorckConstraint {
2390 tcx.mk_param_from_def(&tcx.generics_of(def_id).types[0])
2393 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2397 let mut result = def.all_fields()
2398 .map(|field| tcx.type_of(field.did))
2399 .map(|fty| tcx.dtorck_constraint_for_ty(span, fty, 0, fty))
2400 .collect::<Result<DtorckConstraint, ErrorReported>>()
2401 .unwrap_or(DtorckConstraint::empty());
2402 result.outlives.extend(tcx.destructor_constraints(def));
2405 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2410 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2413 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2414 let item = tcx.hir.expect_item(id);
2415 let vec: Vec<_> = match item.node {
2416 hir::ItemTrait(.., ref trait_item_refs) => {
2417 trait_item_refs.iter()
2418 .map(|trait_item_ref| trait_item_ref.id)
2419 .map(|id| tcx.hir.local_def_id(id.node_id))
2422 hir::ItemImpl(.., ref impl_item_refs) => {
2423 impl_item_refs.iter()
2424 .map(|impl_item_ref| impl_item_ref.id)
2425 .map(|id| tcx.hir.local_def_id(id.node_id))
2428 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2433 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
2434 tcx.hir.span_if_local(def_id).unwrap()
2437 /// If the given def ID describes an item belonging to a trait,
2438 /// return the ID of the trait that the trait item belongs to.
2439 /// Otherwise, return `None`.
2440 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
2441 tcx.opt_associated_item(def_id)
2442 .and_then(|associated_item| {
2443 match associated_item.container {
2444 TraitContainer(def_id) => Some(def_id),
2445 ImplContainer(_) => None
2450 /// See `ParamEnv` struct def'n for details.
2451 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2454 // Compute the bounds on Self and the type parameters.
2456 let bounds = tcx.predicates_of(def_id).instantiate_identity(tcx);
2457 let predicates = bounds.predicates;
2459 // Finally, we have to normalize the bounds in the environment, in
2460 // case they contain any associated type projections. This process
2461 // can yield errors if the put in illegal associated types, like
2462 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2463 // report these errors right here; this doesn't actually feel
2464 // right to me, because constructing the environment feels like a
2465 // kind of a "idempotent" action, but I'm not sure where would be
2466 // a better place. In practice, we construct environments for
2467 // every fn once during type checking, and we'll abort if there
2468 // are any errors at that point, so after type checking you can be
2469 // sure that this will succeed without errors anyway.
2471 let unnormalized_env = ty::ParamEnv::new(tcx.intern_predicates(&predicates),
2472 traits::Reveal::UserFacing);
2474 let body_id = tcx.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
2475 tcx.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_id)
2477 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
2478 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
2481 pub fn provide(providers: &mut ty::maps::Providers) {
2482 util::provide(providers);
2483 *providers = ty::maps::Providers {
2485 associated_item_def_ids,
2486 adt_sized_constraint,
2487 adt_dtorck_constraint,
2491 trait_impls_of: trait_def::trait_impls_of_provider,
2492 relevant_trait_impls_for: trait_def::relevant_trait_impls_provider,
2497 pub fn provide_extern(providers: &mut ty::maps::Providers) {
2498 *providers = ty::maps::Providers {
2499 adt_sized_constraint,
2500 adt_dtorck_constraint,
2501 trait_impls_of: trait_def::trait_impls_of_provider,
2502 relevant_trait_impls_for: trait_def::relevant_trait_impls_provider,
2509 /// A map for the local crate mapping each type to a vector of its
2510 /// inherent impls. This is not meant to be used outside of coherence;
2511 /// rather, you should request the vector for a specific type via
2512 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2513 /// (constructing this map requires touching the entire crate).
2514 #[derive(Clone, Debug)]
2515 pub struct CrateInherentImpls {
2516 pub inherent_impls: DefIdMap<Rc<Vec<DefId>>>,
2519 /// A set of constraints that need to be satisfied in order for
2520 /// a type to be valid for destruction.
2521 #[derive(Clone, Debug)]
2522 pub struct DtorckConstraint<'tcx> {
2523 /// Types that are required to be alive in order for this
2524 /// type to be valid for destruction.
2525 pub outlives: Vec<ty::subst::Kind<'tcx>>,
2526 /// Types that could not be resolved: projections and params.
2527 pub dtorck_types: Vec<Ty<'tcx>>,
2530 impl<'tcx> FromIterator<DtorckConstraint<'tcx>> for DtorckConstraint<'tcx>
2532 fn from_iter<I: IntoIterator<Item=DtorckConstraint<'tcx>>>(iter: I) -> Self {
2533 let mut result = Self::empty();
2535 for constraint in iter {
2536 result.outlives.extend(constraint.outlives);
2537 result.dtorck_types.extend(constraint.dtorck_types);
2545 impl<'tcx> DtorckConstraint<'tcx> {
2546 fn empty() -> DtorckConstraint<'tcx> {
2549 dtorck_types: vec![]
2553 fn dedup<'a>(&mut self) {
2554 let mut outlives = FxHashSet();
2555 let mut dtorck_types = FxHashSet();
2557 self.outlives.retain(|&val| outlives.replace(val).is_none());
2558 self.dtorck_types.retain(|&val| dtorck_types.replace(val).is_none());
2562 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord)]
2563 pub struct SymbolName {
2564 // FIXME: we don't rely on interning or equality here - better have
2565 // this be a `&'tcx str`.
2566 pub name: InternedString
2569 impl Deref for SymbolName {
2572 fn deref(&self) -> &str { &self.name }
2575 impl fmt::Display for SymbolName {
2576 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2577 fmt::Display::fmt(&self.name, fmt)