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, 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 impl<'a, 'gcx, 'tcx> ImplHeader<'tcx> {
162 pub fn with_fresh_ty_vars(selcx: &mut traits::SelectionContext<'a, 'gcx, 'tcx>,
166 let tcx = selcx.tcx();
167 let impl_substs = selcx.infcx().fresh_substs_for_item(DUMMY_SP, impl_def_id);
169 let header = ImplHeader {
170 impl_def_id: impl_def_id,
171 self_ty: tcx.type_of(impl_def_id),
172 trait_ref: tcx.impl_trait_ref(impl_def_id),
173 predicates: tcx.predicates_of(impl_def_id).predicates
174 }.subst(tcx, impl_substs);
176 let traits::Normalized { value: mut header, obligations } =
177 traits::normalize(selcx, traits::ObligationCause::dummy(), &header);
179 header.predicates.extend(obligations.into_iter().map(|o| o.predicate));
184 #[derive(Copy, Clone, Debug)]
185 pub struct AssociatedItem {
188 pub kind: AssociatedKind,
190 pub defaultness: hir::Defaultness,
191 pub container: AssociatedItemContainer,
193 /// Whether this is a method with an explicit self
194 /// as its first argument, allowing method calls.
195 pub method_has_self_argument: bool,
198 #[derive(Copy, Clone, PartialEq, Eq, Debug, RustcEncodable, RustcDecodable)]
199 pub enum AssociatedKind {
205 impl AssociatedItem {
206 pub fn def(&self) -> Def {
208 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
209 AssociatedKind::Method => Def::Method(self.def_id),
210 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
214 /// Tests whether the associated item admits a non-trivial implementation
216 pub fn relevant_for_never<'tcx>(&self) -> bool {
218 AssociatedKind::Const => true,
219 AssociatedKind::Type => true,
220 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
221 AssociatedKind::Method => !self.method_has_self_argument,
226 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
227 pub enum Visibility {
228 /// Visible everywhere (including in other crates).
230 /// Visible only in the given crate-local module.
232 /// Not visible anywhere in the local crate. This is the visibility of private external items.
236 pub trait DefIdTree: Copy {
237 fn parent(self, id: DefId) -> Option<DefId>;
239 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
240 if descendant.krate != ancestor.krate {
244 while descendant != ancestor {
245 match self.parent(descendant) {
246 Some(parent) => descendant = parent,
247 None => return false,
254 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
255 fn parent(self, id: DefId) -> Option<DefId> {
256 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
261 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt) -> Self {
263 hir::Public => Visibility::Public,
264 hir::Visibility::Crate => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
265 hir::Visibility::Restricted { ref path, .. } => match path.def {
266 // If there is no resolution, `resolve` will have already reported an error, so
267 // assume that the visibility is public to avoid reporting more privacy errors.
268 Def::Err => Visibility::Public,
269 def => Visibility::Restricted(def.def_id()),
272 Visibility::Restricted(tcx.hir.get_module_parent(id))
277 /// Returns true if an item with this visibility is accessible from the given block.
278 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
279 let restriction = match self {
280 // Public items are visible everywhere.
281 Visibility::Public => return true,
282 // Private items from other crates are visible nowhere.
283 Visibility::Invisible => return false,
284 // Restricted items are visible in an arbitrary local module.
285 Visibility::Restricted(other) if other.krate != module.krate => return false,
286 Visibility::Restricted(module) => module,
289 tree.is_descendant_of(module, restriction)
292 /// Returns true if this visibility is at least as accessible as the given visibility
293 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
294 let vis_restriction = match vis {
295 Visibility::Public => return self == Visibility::Public,
296 Visibility::Invisible => return true,
297 Visibility::Restricted(module) => module,
300 self.is_accessible_from(vis_restriction, tree)
304 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
306 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
307 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
308 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
309 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
312 /// The crate variances map is computed during typeck and contains the
313 /// variance of every item in the local crate. You should not use it
314 /// directly, because to do so will make your pass dependent on the
315 /// HIR of every item in the local crate. Instead, use
316 /// `tcx.variances_of()` to get the variance for a *particular*
318 pub struct CrateVariancesMap {
319 /// This relation tracks the dependencies between the variance of
320 /// various items. In particular, if `a < b`, then the variance of
321 /// `a` depends on the sources of `b`.
322 pub dependencies: TransitiveRelation<DefId>,
324 /// For each item with generics, maps to a vector of the variance
325 /// of its generics. If an item has no generics, it will have no
327 pub variances: FxHashMap<DefId, Rc<Vec<ty::Variance>>>,
329 /// An empty vector, useful for cloning.
330 pub empty_variance: Rc<Vec<ty::Variance>>,
334 /// `a.xform(b)` combines the variance of a context with the
335 /// variance of a type with the following meaning. If we are in a
336 /// context with variance `a`, and we encounter a type argument in
337 /// a position with variance `b`, then `a.xform(b)` is the new
338 /// variance with which the argument appears.
344 /// Here, the "ambient" variance starts as covariant. `*mut T` is
345 /// invariant with respect to `T`, so the variance in which the
346 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
347 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
348 /// respect to its type argument `T`, and hence the variance of
349 /// the `i32` here is `Invariant.xform(Covariant)`, which results
350 /// (again) in `Invariant`.
354 /// fn(*const Vec<i32>, *mut Vec<i32)
356 /// The ambient variance is covariant. A `fn` type is
357 /// contravariant with respect to its parameters, so the variance
358 /// within which both pointer types appear is
359 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
360 /// T` is covariant with respect to `T`, so the variance within
361 /// which the first `Vec<i32>` appears is
362 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
363 /// is true for its `i32` argument. In the `*mut T` case, the
364 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
365 /// and hence the outermost type is `Invariant` with respect to
366 /// `Vec<i32>` (and its `i32` argument).
368 /// Source: Figure 1 of "Taming the Wildcards:
369 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
370 pub fn xform(self, v: ty::Variance) -> ty::Variance {
372 // Figure 1, column 1.
373 (ty::Covariant, ty::Covariant) => ty::Covariant,
374 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
375 (ty::Covariant, ty::Invariant) => ty::Invariant,
376 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
378 // Figure 1, column 2.
379 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
380 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
381 (ty::Contravariant, ty::Invariant) => ty::Invariant,
382 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
384 // Figure 1, column 3.
385 (ty::Invariant, _) => ty::Invariant,
387 // Figure 1, column 4.
388 (ty::Bivariant, _) => ty::Bivariant,
393 // Contains information needed to resolve types and (in the future) look up
394 // the types of AST nodes.
395 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
396 pub struct CReaderCacheKey {
401 // Flags that we track on types. These flags are propagated upwards
402 // through the type during type construction, so that we can quickly
403 // check whether the type has various kinds of types in it without
404 // recursing over the type itself.
406 flags TypeFlags: u32 {
407 const HAS_PARAMS = 1 << 0,
408 const HAS_SELF = 1 << 1,
409 const HAS_TY_INFER = 1 << 2,
410 const HAS_RE_INFER = 1 << 3,
411 const HAS_RE_SKOL = 1 << 4,
412 const HAS_RE_EARLY_BOUND = 1 << 5,
413 const HAS_FREE_REGIONS = 1 << 6,
414 const HAS_TY_ERR = 1 << 7,
415 const HAS_PROJECTION = 1 << 8,
416 const HAS_TY_CLOSURE = 1 << 9,
418 // true if there are "names" of types and regions and so forth
419 // that are local to a particular fn
420 const HAS_LOCAL_NAMES = 1 << 10,
422 // Present if the type belongs in a local type context.
423 // Only set for TyInfer other than Fresh.
424 const KEEP_IN_LOCAL_TCX = 1 << 11,
426 // Is there a projection that does not involve a bound region?
427 // Currently we can't normalize projections w/ bound regions.
428 const HAS_NORMALIZABLE_PROJECTION = 1 << 12,
430 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
431 TypeFlags::HAS_SELF.bits |
432 TypeFlags::HAS_RE_EARLY_BOUND.bits,
434 // Flags representing the nominal content of a type,
435 // computed by FlagsComputation. If you add a new nominal
436 // flag, it should be added here too.
437 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
438 TypeFlags::HAS_SELF.bits |
439 TypeFlags::HAS_TY_INFER.bits |
440 TypeFlags::HAS_RE_INFER.bits |
441 TypeFlags::HAS_RE_SKOL.bits |
442 TypeFlags::HAS_RE_EARLY_BOUND.bits |
443 TypeFlags::HAS_FREE_REGIONS.bits |
444 TypeFlags::HAS_TY_ERR.bits |
445 TypeFlags::HAS_PROJECTION.bits |
446 TypeFlags::HAS_TY_CLOSURE.bits |
447 TypeFlags::HAS_LOCAL_NAMES.bits |
448 TypeFlags::KEEP_IN_LOCAL_TCX.bits,
452 pub struct TyS<'tcx> {
453 pub sty: TypeVariants<'tcx>,
454 pub flags: TypeFlags,
456 // the maximal depth of any bound regions appearing in this type.
460 impl<'tcx> PartialEq for TyS<'tcx> {
462 fn eq(&self, other: &TyS<'tcx>) -> bool {
463 // (self as *const _) == (other as *const _)
464 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
467 impl<'tcx> Eq for TyS<'tcx> {}
469 impl<'tcx> Hash for TyS<'tcx> {
470 fn hash<H: Hasher>(&self, s: &mut H) {
471 (self as *const TyS).hash(s)
475 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for ty::TyS<'tcx> {
476 fn hash_stable<W: StableHasherResult>(&self,
477 hcx: &mut StableHashingContext<'a, 'tcx>,
478 hasher: &mut StableHasher<W>) {
482 // The other fields just provide fast access to information that is
483 // also contained in `sty`, so no need to hash them.
488 sty.hash_stable(hcx, hasher);
492 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
494 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
495 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
497 /// A wrapper for slices with the additional invariant
498 /// that the slice is interned and no other slice with
499 /// the same contents can exist in the same context.
500 /// This means we can use pointer + length for both
501 /// equality comparisons and hashing.
502 #[derive(Debug, RustcEncodable)]
503 pub struct Slice<T>([T]);
505 impl<T> PartialEq for Slice<T> {
507 fn eq(&self, other: &Slice<T>) -> bool {
508 (&self.0 as *const [T]) == (&other.0 as *const [T])
511 impl<T> Eq for Slice<T> {}
513 impl<T> Hash for Slice<T> {
514 fn hash<H: Hasher>(&self, s: &mut H) {
515 (self.as_ptr(), self.len()).hash(s)
519 impl<T> Deref for Slice<T> {
521 fn deref(&self) -> &[T] {
526 impl<'a, T> IntoIterator for &'a Slice<T> {
528 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
529 fn into_iter(self) -> Self::IntoIter {
534 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {}
537 pub fn empty<'a>() -> &'a Slice<T> {
539 mem::transmute(slice::from_raw_parts(0x1 as *const T, 0))
544 /// Upvars do not get their own node-id. Instead, we use the pair of
545 /// the original var id (that is, the root variable that is referenced
546 /// by the upvar) and the id of the closure expression.
547 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
550 pub closure_expr_id: NodeId,
553 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
554 pub enum BorrowKind {
555 /// Data must be immutable and is aliasable.
558 /// Data must be immutable but not aliasable. This kind of borrow
559 /// cannot currently be expressed by the user and is used only in
560 /// implicit closure bindings. It is needed when the closure
561 /// is borrowing or mutating a mutable referent, e.g.:
563 /// let x: &mut isize = ...;
564 /// let y = || *x += 5;
566 /// If we were to try to translate this closure into a more explicit
567 /// form, we'd encounter an error with the code as written:
569 /// struct Env { x: & &mut isize }
570 /// let x: &mut isize = ...;
571 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
572 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
574 /// This is then illegal because you cannot mutate a `&mut` found
575 /// in an aliasable location. To solve, you'd have to translate with
576 /// an `&mut` borrow:
578 /// struct Env { x: & &mut isize }
579 /// let x: &mut isize = ...;
580 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
581 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
583 /// Now the assignment to `**env.x` is legal, but creating a
584 /// mutable pointer to `x` is not because `x` is not mutable. We
585 /// could fix this by declaring `x` as `let mut x`. This is ok in
586 /// user code, if awkward, but extra weird for closures, since the
587 /// borrow is hidden.
589 /// So we introduce a "unique imm" borrow -- the referent is
590 /// immutable, but not aliasable. This solves the problem. For
591 /// simplicity, we don't give users the way to express this
592 /// borrow, it's just used when translating closures.
595 /// Data is mutable and not aliasable.
599 /// Information describing the capture of an upvar. This is computed
600 /// during `typeck`, specifically by `regionck`.
601 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
602 pub enum UpvarCapture<'tcx> {
603 /// Upvar is captured by value. This is always true when the
604 /// closure is labeled `move`, but can also be true in other cases
605 /// depending on inference.
608 /// Upvar is captured by reference.
609 ByRef(UpvarBorrow<'tcx>),
612 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
613 pub struct UpvarBorrow<'tcx> {
614 /// The kind of borrow: by-ref upvars have access to shared
615 /// immutable borrows, which are not part of the normal language
617 pub kind: BorrowKind,
619 /// Region of the resulting reference.
620 pub region: ty::Region<'tcx>,
623 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
625 #[derive(Copy, Clone)]
626 pub struct ClosureUpvar<'tcx> {
632 #[derive(Clone, Copy, PartialEq)]
633 pub enum IntVarValue {
635 UintType(ast::UintTy),
638 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
639 pub struct TypeParameterDef {
643 pub has_default: bool,
644 pub object_lifetime_default: ObjectLifetimeDefault,
646 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
647 /// on generic parameter `T`, asserts data behind the parameter
648 /// `T` won't be accessed during the parent type's `Drop` impl.
649 pub pure_wrt_drop: bool,
652 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
653 pub struct RegionParameterDef {
657 pub issue_32330: Option<ty::Issue32330>,
659 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
660 /// on generic parameter `'a`, asserts data of lifetime `'a`
661 /// won't be accessed during the parent type's `Drop` impl.
662 pub pure_wrt_drop: bool,
665 impl RegionParameterDef {
666 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
667 ty::EarlyBoundRegion {
674 pub fn to_bound_region(&self) -> ty::BoundRegion {
675 self.to_early_bound_region_data().to_bound_region()
679 impl ty::EarlyBoundRegion {
680 pub fn to_bound_region(&self) -> ty::BoundRegion {
681 ty::BoundRegion::BrNamed(self.def_id, self.name)
685 /// Information about the formal type/lifetime parameters associated
686 /// with an item or method. Analogous to hir::Generics.
687 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
688 pub struct Generics {
689 pub parent: Option<DefId>,
690 pub parent_regions: u32,
691 pub parent_types: u32,
692 pub regions: Vec<RegionParameterDef>,
693 pub types: Vec<TypeParameterDef>,
695 /// Reverse map to each `TypeParameterDef`'s `index` field, from
696 /// `def_id.index` (`def_id.krate` is the same as the item's).
697 pub type_param_to_index: BTreeMap<DefIndex, u32>,
703 pub fn parent_count(&self) -> usize {
704 self.parent_regions as usize + self.parent_types as usize
707 pub fn own_count(&self) -> usize {
708 self.regions.len() + self.types.len()
711 pub fn count(&self) -> usize {
712 self.parent_count() + self.own_count()
715 pub fn region_param(&self, param: &EarlyBoundRegion) -> &RegionParameterDef {
716 assert_eq!(self.parent_count(), 0);
717 &self.regions[param.index as usize - self.has_self as usize]
720 pub fn type_param(&self, param: &ParamTy) -> &TypeParameterDef {
721 assert_eq!(self.parent_count(), 0);
722 &self.types[param.idx as usize - self.has_self as usize - self.regions.len()]
726 /// Bounds on generics.
727 #[derive(Clone, Default)]
728 pub struct GenericPredicates<'tcx> {
729 pub parent: Option<DefId>,
730 pub predicates: Vec<Predicate<'tcx>>,
733 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
734 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
736 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
737 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
738 -> InstantiatedPredicates<'tcx> {
739 let mut instantiated = InstantiatedPredicates::empty();
740 self.instantiate_into(tcx, &mut instantiated, substs);
743 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
744 -> InstantiatedPredicates<'tcx> {
745 InstantiatedPredicates {
746 predicates: self.predicates.subst(tcx, substs)
750 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
751 instantiated: &mut InstantiatedPredicates<'tcx>,
752 substs: &Substs<'tcx>) {
753 if let Some(def_id) = self.parent {
754 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
756 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
759 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
760 -> InstantiatedPredicates<'tcx> {
761 let mut instantiated = InstantiatedPredicates::empty();
762 self.instantiate_identity_into(tcx, &mut instantiated);
766 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
767 instantiated: &mut InstantiatedPredicates<'tcx>) {
768 if let Some(def_id) = self.parent {
769 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
771 instantiated.predicates.extend(&self.predicates)
774 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
775 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
776 -> InstantiatedPredicates<'tcx>
778 assert_eq!(self.parent, None);
779 InstantiatedPredicates {
780 predicates: self.predicates.iter().map(|pred| {
781 pred.subst_supertrait(tcx, poly_trait_ref)
787 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
788 pub enum Predicate<'tcx> {
789 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
790 /// the `Self` type of the trait reference and `A`, `B`, and `C`
791 /// would be the type parameters.
792 Trait(PolyTraitPredicate<'tcx>),
794 /// where `T1 == T2`.
795 Equate(PolyEquatePredicate<'tcx>),
798 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
801 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
803 /// where <T as TraitRef>::Name == X, approximately.
804 /// See `ProjectionPredicate` struct for details.
805 Projection(PolyProjectionPredicate<'tcx>),
808 WellFormed(Ty<'tcx>),
810 /// trait must be object-safe
813 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
814 /// for some substitutions `...` and T being a closure type.
815 /// Satisfied (or refuted) once we know the closure's kind.
816 ClosureKind(DefId, ClosureKind),
819 Subtype(PolySubtypePredicate<'tcx>),
822 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
823 /// Performs a substitution suitable for going from a
824 /// poly-trait-ref to supertraits that must hold if that
825 /// poly-trait-ref holds. This is slightly different from a normal
826 /// substitution in terms of what happens with bound regions. See
827 /// lengthy comment below for details.
828 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
829 trait_ref: &ty::PolyTraitRef<'tcx>)
830 -> ty::Predicate<'tcx>
832 // The interaction between HRTB and supertraits is not entirely
833 // obvious. Let me walk you (and myself) through an example.
835 // Let's start with an easy case. Consider two traits:
837 // trait Foo<'a> : Bar<'a,'a> { }
838 // trait Bar<'b,'c> { }
840 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
841 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
842 // knew that `Foo<'x>` (for any 'x) then we also know that
843 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
844 // normal substitution.
846 // In terms of why this is sound, the idea is that whenever there
847 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
848 // holds. So if there is an impl of `T:Foo<'a>` that applies to
849 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
852 // Another example to be careful of is this:
854 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
855 // trait Bar1<'b,'c> { }
857 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
858 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
859 // reason is similar to the previous example: any impl of
860 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
861 // basically we would want to collapse the bound lifetimes from
862 // the input (`trait_ref`) and the supertraits.
864 // To achieve this in practice is fairly straightforward. Let's
865 // consider the more complicated scenario:
867 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
868 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
869 // where both `'x` and `'b` would have a DB index of 1.
870 // The substitution from the input trait-ref is therefore going to be
871 // `'a => 'x` (where `'x` has a DB index of 1).
872 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
873 // early-bound parameter and `'b' is a late-bound parameter with a
875 // - If we replace `'a` with `'x` from the input, it too will have
876 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
877 // just as we wanted.
879 // There is only one catch. If we just apply the substitution `'a
880 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
881 // adjust the DB index because we substituting into a binder (it
882 // tries to be so smart...) resulting in `for<'x> for<'b>
883 // Bar1<'x,'b>` (we have no syntax for this, so use your
884 // imagination). Basically the 'x will have DB index of 2 and 'b
885 // will have DB index of 1. Not quite what we want. So we apply
886 // the substitution to the *contents* of the trait reference,
887 // rather than the trait reference itself (put another way, the
888 // substitution code expects equal binding levels in the values
889 // from the substitution and the value being substituted into, and
890 // this trick achieves that).
892 let substs = &trait_ref.0.substs;
894 Predicate::Trait(ty::Binder(ref data)) =>
895 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
896 Predicate::Equate(ty::Binder(ref data)) =>
897 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
898 Predicate::Subtype(ty::Binder(ref data)) =>
899 Predicate::Subtype(ty::Binder(data.subst(tcx, substs))),
900 Predicate::RegionOutlives(ty::Binder(ref data)) =>
901 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
902 Predicate::TypeOutlives(ty::Binder(ref data)) =>
903 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
904 Predicate::Projection(ty::Binder(ref data)) =>
905 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
906 Predicate::WellFormed(data) =>
907 Predicate::WellFormed(data.subst(tcx, substs)),
908 Predicate::ObjectSafe(trait_def_id) =>
909 Predicate::ObjectSafe(trait_def_id),
910 Predicate::ClosureKind(closure_def_id, kind) =>
911 Predicate::ClosureKind(closure_def_id, kind),
916 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
917 pub struct TraitPredicate<'tcx> {
918 pub trait_ref: TraitRef<'tcx>
920 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
922 impl<'tcx> TraitPredicate<'tcx> {
923 pub fn def_id(&self) -> DefId {
924 self.trait_ref.def_id
927 /// Creates the dep-node for selecting/evaluating this trait reference.
928 fn dep_node(&self) -> DepNode<DefId> {
929 // Extact the trait-def and first def-id from inputs. See the
930 // docs for `DepNode::TraitSelect` for more information.
931 let trait_def_id = self.def_id();
934 .flat_map(|t| t.walk())
935 .filter_map(|t| match t.sty {
936 ty::TyAdt(adt_def, _) => Some(adt_def.did),
940 .unwrap_or(trait_def_id);
941 DepNode::TraitSelect {
942 trait_def_id: trait_def_id,
943 input_def_id: input_def_id
947 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
948 self.trait_ref.input_types()
951 pub fn self_ty(&self) -> Ty<'tcx> {
952 self.trait_ref.self_ty()
956 impl<'tcx> PolyTraitPredicate<'tcx> {
957 pub fn def_id(&self) -> DefId {
958 // ok to skip binder since trait def-id does not care about regions
962 pub fn dep_node(&self) -> DepNode<DefId> {
963 // ok to skip binder since depnode does not care about regions
968 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
969 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
970 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
972 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
973 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
974 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
975 pub type PolyRegionOutlivesPredicate<'tcx> = PolyOutlivesPredicate<ty::Region<'tcx>,
977 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
979 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
980 pub struct SubtypePredicate<'tcx> {
981 pub a_is_expected: bool,
985 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
987 /// This kind of predicate has no *direct* correspondent in the
988 /// syntax, but it roughly corresponds to the syntactic forms:
990 /// 1. `T : TraitRef<..., Item=Type>`
991 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
993 /// In particular, form #1 is "desugared" to the combination of a
994 /// normal trait predicate (`T : TraitRef<...>`) and one of these
995 /// predicates. Form #2 is a broader form in that it also permits
996 /// equality between arbitrary types. Processing an instance of Form
997 /// #2 eventually yields one of these `ProjectionPredicate`
998 /// instances to normalize the LHS.
999 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1000 pub struct ProjectionPredicate<'tcx> {
1001 pub projection_ty: ProjectionTy<'tcx>,
1005 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1007 impl<'tcx> PolyProjectionPredicate<'tcx> {
1008 pub fn item_name(&self, tcx: TyCtxt) -> Name {
1009 self.0.projection_ty.item_name(tcx) // safe to skip the binder to access a name
1013 pub trait ToPolyTraitRef<'tcx> {
1014 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1017 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1018 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1019 assert!(!self.has_escaping_regions());
1020 ty::Binder(self.clone())
1024 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1025 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1026 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1030 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
1031 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1032 // Note: unlike with TraitRef::to_poly_trait_ref(),
1033 // self.0.trait_ref is permitted to have escaping regions.
1034 // This is because here `self` has a `Binder` and so does our
1035 // return value, so we are preserving the number of binding
1037 ty::Binder(self.0.projection_ty.trait_ref)
1041 pub trait ToPredicate<'tcx> {
1042 fn to_predicate(&self) -> Predicate<'tcx>;
1045 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1046 fn to_predicate(&self) -> Predicate<'tcx> {
1047 // we're about to add a binder, so let's check that we don't
1048 // accidentally capture anything, or else that might be some
1049 // weird debruijn accounting.
1050 assert!(!self.has_escaping_regions());
1052 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
1053 trait_ref: self.clone()
1058 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1059 fn to_predicate(&self) -> Predicate<'tcx> {
1060 ty::Predicate::Trait(self.to_poly_trait_predicate())
1064 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
1065 fn to_predicate(&self) -> Predicate<'tcx> {
1066 Predicate::Equate(self.clone())
1070 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1071 fn to_predicate(&self) -> Predicate<'tcx> {
1072 Predicate::RegionOutlives(self.clone())
1076 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1077 fn to_predicate(&self) -> Predicate<'tcx> {
1078 Predicate::TypeOutlives(self.clone())
1082 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1083 fn to_predicate(&self) -> Predicate<'tcx> {
1084 Predicate::Projection(self.clone())
1088 impl<'tcx> Predicate<'tcx> {
1089 /// Iterates over the types in this predicate. Note that in all
1090 /// cases this is skipping over a binder, so late-bound regions
1091 /// with depth 0 are bound by the predicate.
1092 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1093 let vec: Vec<_> = match *self {
1094 ty::Predicate::Trait(ref data) => {
1095 data.skip_binder().input_types().collect()
1097 ty::Predicate::Equate(ty::Binder(ref data)) => {
1098 vec![data.0, data.1]
1100 ty::Predicate::Subtype(ty::Binder(SubtypePredicate { a, b, a_is_expected: _ })) => {
1103 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
1106 ty::Predicate::RegionOutlives(..) => {
1109 ty::Predicate::Projection(ref data) => {
1110 let trait_inputs = data.0.projection_ty.trait_ref.input_types();
1111 trait_inputs.chain(Some(data.0.ty)).collect()
1113 ty::Predicate::WellFormed(data) => {
1116 ty::Predicate::ObjectSafe(_trait_def_id) => {
1119 ty::Predicate::ClosureKind(_closure_def_id, _kind) => {
1124 // The only reason to collect into a vector here is that I was
1125 // too lazy to make the full (somewhat complicated) iterator
1126 // type that would be needed here. But I wanted this fn to
1127 // return an iterator conceptually, rather than a `Vec`, so as
1128 // to be closer to `Ty::walk`.
1132 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1134 Predicate::Trait(ref t) => {
1135 Some(t.to_poly_trait_ref())
1137 Predicate::Projection(..) |
1138 Predicate::Equate(..) |
1139 Predicate::Subtype(..) |
1140 Predicate::RegionOutlives(..) |
1141 Predicate::WellFormed(..) |
1142 Predicate::ObjectSafe(..) |
1143 Predicate::ClosureKind(..) |
1144 Predicate::TypeOutlives(..) => {
1151 /// Represents the bounds declared on a particular set of type
1152 /// parameters. Should eventually be generalized into a flag list of
1153 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1154 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1155 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1156 /// the `GenericPredicates` are expressed in terms of the bound type
1157 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1158 /// represented a set of bounds for some particular instantiation,
1159 /// meaning that the generic parameters have been substituted with
1164 /// struct Foo<T,U:Bar<T>> { ... }
1166 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1167 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1168 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1169 /// [usize:Bar<isize>]]`.
1171 pub struct InstantiatedPredicates<'tcx> {
1172 pub predicates: Vec<Predicate<'tcx>>,
1175 impl<'tcx> InstantiatedPredicates<'tcx> {
1176 pub fn empty() -> InstantiatedPredicates<'tcx> {
1177 InstantiatedPredicates { predicates: vec![] }
1180 pub fn is_empty(&self) -> bool {
1181 self.predicates.is_empty()
1185 /// When type checking, we use the `ParamEnv` to track
1186 /// details about the set of where-clauses that are in scope at this
1187 /// particular point.
1188 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1189 pub struct ParamEnv<'tcx> {
1190 /// Obligations that the caller must satisfy. This is basically
1191 /// the set of bounds on the in-scope type parameters, translated
1192 /// into Obligations, and elaborated and normalized.
1193 pub caller_bounds: &'tcx Slice<ty::Predicate<'tcx>>,
1195 /// Typically, this is `Reveal::UserFacing`, but during trans we
1196 /// want `Reveal::All` -- note that this is always paired with an
1197 /// empty environment. To get that, use `ParamEnv::reveal()`.
1198 pub reveal: traits::Reveal,
1201 impl<'tcx> ParamEnv<'tcx> {
1202 /// Creates a suitable environment in which to perform trait
1203 /// queries on the given value. This will either be `self` *or*
1204 /// the empty environment, depending on whether `value` references
1205 /// type parameters that are in scope. (If it doesn't, then any
1206 /// judgements should be completely independent of the context,
1207 /// and hence we can safely use the empty environment so as to
1208 /// enable more sharing across functions.)
1210 /// NB: This is a mildly dubious thing to do, in that a function
1211 /// (or other environment) might have wacky where-clauses like
1212 /// `where Box<u32>: Copy`, which are clearly never
1213 /// satisfiable. The code will at present ignore these,
1214 /// effectively, when type-checking the body of said
1215 /// function. This preserves existing behavior in any
1216 /// case. --nmatsakis
1217 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1218 assert!(!value.needs_infer());
1219 if value.has_param_types() || value.has_self_ty() {
1226 param_env: ParamEnv::empty(self.reveal),
1233 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1234 pub struct ParamEnvAnd<'tcx, T> {
1235 pub param_env: ParamEnv<'tcx>,
1239 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1240 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1241 (self.param_env, self.value)
1245 #[derive(Copy, Clone, Debug)]
1246 pub struct Destructor {
1247 /// The def-id of the destructor method
1252 flags AdtFlags: u32 {
1253 const NO_ADT_FLAGS = 0,
1254 const IS_ENUM = 1 << 0,
1255 const IS_PHANTOM_DATA = 1 << 1,
1256 const IS_FUNDAMENTAL = 1 << 2,
1257 const IS_UNION = 1 << 3,
1258 const IS_BOX = 1 << 4,
1263 pub struct VariantDef {
1264 /// The variant's DefId. If this is a tuple-like struct,
1265 /// this is the DefId of the struct's ctor.
1267 pub name: Name, // struct's name if this is a struct
1268 pub discr: VariantDiscr,
1269 pub fields: Vec<FieldDef>,
1270 pub ctor_kind: CtorKind,
1273 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1274 pub enum VariantDiscr {
1275 /// Explicit value for this variant, i.e. `X = 123`.
1276 /// The `DefId` corresponds to the embedded constant.
1279 /// The previous variant's discriminant plus one.
1280 /// For efficiency reasons, the distance from the
1281 /// last `Explicit` discriminant is being stored,
1282 /// or `0` for the first variant, if it has none.
1287 pub struct FieldDef {
1290 pub vis: Visibility,
1293 /// The definition of an abstract data type - a struct or enum.
1295 /// These are all interned (by intern_adt_def) into the adt_defs
1299 pub variants: Vec<VariantDef>,
1301 pub repr: ReprOptions,
1304 impl PartialEq for AdtDef {
1305 // AdtDef are always interned and this is part of TyS equality
1307 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1310 impl Eq for AdtDef {}
1312 impl Hash for AdtDef {
1314 fn hash<H: Hasher>(&self, s: &mut H) {
1315 (self as *const AdtDef).hash(s)
1319 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1320 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1325 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1328 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for AdtDef {
1329 fn hash_stable<W: StableHasherResult>(&self,
1330 hcx: &mut StableHashingContext<'a, 'tcx>,
1331 hasher: &mut StableHasher<W>) {
1339 did.hash_stable(hcx, hasher);
1340 variants.hash_stable(hcx, hasher);
1341 flags.hash_stable(hcx, hasher);
1342 repr.hash_stable(hcx, hasher);
1346 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1347 pub enum AdtKind { Struct, Union, Enum }
1350 #[derive(RustcEncodable, RustcDecodable, Default)]
1351 flags ReprFlags: u8 {
1352 const IS_C = 1 << 0,
1353 const IS_PACKED = 1 << 1,
1354 const IS_SIMD = 1 << 2,
1355 // Internal only for now. If true, don't reorder fields.
1356 const IS_LINEAR = 1 << 3,
1358 // Any of these flags being set prevent field reordering optimisation.
1359 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1360 ReprFlags::IS_PACKED.bits |
1361 ReprFlags::IS_SIMD.bits |
1362 ReprFlags::IS_LINEAR.bits,
1366 impl_stable_hash_for!(struct ReprFlags {
1372 /// Represents the repr options provided by the user,
1373 #[derive(Copy, Clone, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1374 pub struct ReprOptions {
1375 pub int: Option<attr::IntType>,
1377 pub flags: ReprFlags,
1380 impl_stable_hash_for!(struct ReprOptions {
1387 pub fn new(tcx: TyCtxt, did: DefId) -> ReprOptions {
1388 let mut flags = ReprFlags::empty();
1389 let mut size = None;
1390 let mut max_align = 0;
1391 for attr in tcx.get_attrs(did).iter() {
1392 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1393 flags.insert(match r {
1394 attr::ReprExtern => ReprFlags::IS_C,
1395 attr::ReprPacked => ReprFlags::IS_PACKED,
1396 attr::ReprSimd => ReprFlags::IS_SIMD,
1397 attr::ReprInt(i) => {
1401 attr::ReprAlign(align) => {
1402 max_align = cmp::max(align, max_align);
1409 // FIXME(eddyb) This is deprecated and should be removed.
1410 if tcx.has_attr(did, "simd") {
1411 flags.insert(ReprFlags::IS_SIMD);
1414 // This is here instead of layout because the choice must make it into metadata.
1415 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1416 flags.insert(ReprFlags::IS_LINEAR);
1418 ReprOptions { int: size, align: max_align, flags: flags }
1422 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1424 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1426 pub fn packed(&self) -> bool { self.flags.contains(ReprFlags::IS_PACKED) }
1428 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1430 pub fn discr_type(&self) -> attr::IntType {
1431 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Is))
1434 /// Returns true if this `#[repr()]` should inhabit "smart enum
1435 /// layout" optimizations, such as representing `Foo<&T>` as a
1437 pub fn inhibit_enum_layout_opt(&self) -> bool {
1438 self.c() || self.int.is_some()
1442 impl<'a, 'gcx, 'tcx> AdtDef {
1446 variants: Vec<VariantDef>,
1447 repr: ReprOptions) -> Self {
1448 let mut flags = AdtFlags::NO_ADT_FLAGS;
1449 let attrs = tcx.get_attrs(did);
1450 if attr::contains_name(&attrs, "fundamental") {
1451 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1453 if Some(did) == tcx.lang_items.phantom_data() {
1454 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1456 if Some(did) == tcx.lang_items.owned_box() {
1457 flags = flags | AdtFlags::IS_BOX;
1460 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
1461 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
1462 AdtKind::Struct => {}
1473 pub fn is_struct(&self) -> bool {
1474 !self.is_union() && !self.is_enum()
1478 pub fn is_union(&self) -> bool {
1479 self.flags.intersects(AdtFlags::IS_UNION)
1483 pub fn is_enum(&self) -> bool {
1484 self.flags.intersects(AdtFlags::IS_ENUM)
1487 /// Returns the kind of the ADT - Struct or Enum.
1489 pub fn adt_kind(&self) -> AdtKind {
1492 } else if self.is_union() {
1499 pub fn descr(&self) -> &'static str {
1500 match self.adt_kind() {
1501 AdtKind::Struct => "struct",
1502 AdtKind::Union => "union",
1503 AdtKind::Enum => "enum",
1507 pub fn variant_descr(&self) -> &'static str {
1508 match self.adt_kind() {
1509 AdtKind::Struct => "struct",
1510 AdtKind::Union => "union",
1511 AdtKind::Enum => "variant",
1515 /// Returns whether this type is #[fundamental] for the purposes
1516 /// of coherence checking.
1518 pub fn is_fundamental(&self) -> bool {
1519 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
1522 /// Returns true if this is PhantomData<T>.
1524 pub fn is_phantom_data(&self) -> bool {
1525 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
1528 /// Returns true if this is Box<T>.
1530 pub fn is_box(&self) -> bool {
1531 self.flags.intersects(AdtFlags::IS_BOX)
1534 /// Returns whether this type has a destructor.
1535 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
1536 self.destructor(tcx).is_some()
1539 /// Asserts this is a struct and returns the struct's unique
1541 pub fn struct_variant(&self) -> &VariantDef {
1542 assert!(!self.is_enum());
1547 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
1548 tcx.predicates_of(self.did)
1551 /// Returns an iterator over all fields contained
1554 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
1555 self.variants.iter().flat_map(|v| v.fields.iter())
1559 pub fn is_univariant(&self) -> bool {
1560 self.variants.len() == 1
1563 pub fn is_payloadfree(&self) -> bool {
1564 !self.variants.is_empty() &&
1565 self.variants.iter().all(|v| v.fields.is_empty())
1568 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
1571 .find(|v| v.did == vid)
1572 .expect("variant_with_id: unknown variant")
1575 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1578 .position(|v| v.did == vid)
1579 .expect("variant_index_with_id: unknown variant")
1582 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
1584 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
1585 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
1586 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.struct_variant(),
1587 _ => bug!("unexpected def {:?} in variant_of_def", def)
1592 pub fn discriminants(&'a self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1593 -> impl Iterator<Item=ConstInt> + 'a {
1594 let repr_type = self.repr.discr_type();
1595 let initial = repr_type.initial_discriminant(tcx.global_tcx());
1596 let mut prev_discr = None::<ConstInt>;
1597 self.variants.iter().map(move |v| {
1598 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr());
1599 if let VariantDiscr::Explicit(expr_did) = v.discr {
1600 let substs = Substs::empty();
1601 match tcx.const_eval((expr_did, substs)) {
1602 Ok(ConstVal::Integral(v)) => {
1606 if !expr_did.is_local() {
1607 span_bug!(tcx.def_span(expr_did),
1608 "variant discriminant evaluation succeeded \
1609 in its crate but failed locally: {:?}", err);
1614 prev_discr = Some(discr);
1620 /// Compute the discriminant value used by a specific variant.
1621 /// Unlike `discriminants`, this is (amortized) constant-time,
1622 /// only doing at most one query for evaluating an explicit
1623 /// discriminant (the last one before the requested variant),
1624 /// assuming there are no constant-evaluation errors there.
1625 pub fn discriminant_for_variant(&self,
1626 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1627 variant_index: usize)
1629 let repr_type = self.repr.discr_type();
1630 let mut explicit_value = repr_type.initial_discriminant(tcx.global_tcx());
1631 let mut explicit_index = variant_index;
1633 match self.variants[explicit_index].discr {
1634 ty::VariantDiscr::Relative(0) => break,
1635 ty::VariantDiscr::Relative(distance) => {
1636 explicit_index -= distance;
1638 ty::VariantDiscr::Explicit(expr_did) => {
1639 let substs = Substs::empty();
1640 match tcx.const_eval((expr_did, substs)) {
1641 Ok(ConstVal::Integral(v)) => {
1646 if !expr_did.is_local() {
1647 span_bug!(tcx.def_span(expr_did),
1648 "variant discriminant evaluation succeeded \
1649 in its crate but failed locally: {:?}", err);
1651 if explicit_index == 0 {
1654 explicit_index -= 1;
1660 let discr = explicit_value.to_u128_unchecked()
1661 .wrapping_add((variant_index - explicit_index) as u128);
1663 attr::UnsignedInt(ty) => {
1664 ConstInt::new_unsigned_truncating(discr, ty,
1665 tcx.sess.target.uint_type)
1667 attr::SignedInt(ty) => {
1668 ConstInt::new_signed_truncating(discr as i128, ty,
1669 tcx.sess.target.int_type)
1674 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
1675 tcx.adt_destructor(self.did)
1678 /// Returns a list of types such that `Self: Sized` if and only
1679 /// if that type is Sized, or `TyErr` if this type is recursive.
1681 /// Oddly enough, checking that the sized-constraint is Sized is
1682 /// actually more expressive than checking all members:
1683 /// the Sized trait is inductive, so an associated type that references
1684 /// Self would prevent its containing ADT from being Sized.
1686 /// Due to normalization being eager, this applies even if
1687 /// the associated type is behind a pointer, e.g. issue #31299.
1688 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
1689 match queries::adt_sized_constraint::try_get(tcx, DUMMY_SP, self.did) {
1692 debug!("adt_sized_constraint: {:?} is recursive", self);
1693 // This should be reported as an error by `check_representable`.
1695 // Consider the type as Sized in the meanwhile to avoid
1697 tcx.intern_type_list(&[tcx.types.err])
1702 fn sized_constraint_for_ty(&self,
1703 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1706 let result = match ty.sty {
1707 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
1708 TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
1709 TyArray(..) | TyClosure(..) | TyNever => {
1713 TyStr | TyDynamic(..) | TySlice(_) | TyError => {
1714 // these are never sized - return the target type
1718 TyTuple(ref tys, _) => {
1721 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
1725 TyAdt(adt, substs) => {
1727 let adt_tys = adt.sized_constraint(tcx);
1728 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
1731 .map(|ty| ty.subst(tcx, substs))
1732 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
1736 TyProjection(..) | TyAnon(..) => {
1737 // must calculate explicitly.
1738 // FIXME: consider special-casing always-Sized projections
1743 // perf hack: if there is a `T: Sized` bound, then
1744 // we know that `T` is Sized and do not need to check
1747 let sized_trait = match tcx.lang_items.sized_trait() {
1749 _ => return vec![ty]
1751 let sized_predicate = Binder(TraitRef {
1752 def_id: sized_trait,
1753 substs: tcx.mk_substs_trait(ty, &[])
1755 let predicates = tcx.predicates_of(self.did).predicates;
1756 if predicates.into_iter().any(|p| p == sized_predicate) {
1764 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
1768 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
1773 impl<'a, 'gcx, 'tcx> VariantDef {
1775 pub fn find_field_named(&self, name: ast::Name) -> Option<&FieldDef> {
1776 self.index_of_field_named(name).map(|index| &self.fields[index])
1779 pub fn index_of_field_named(&self, name: ast::Name) -> Option<usize> {
1780 if let Some(index) = self.fields.iter().position(|f| f.name == name) {
1783 let mut ident = name.to_ident();
1784 while ident.ctxt != SyntaxContext::empty() {
1785 ident.ctxt.remove_mark();
1786 if let Some(field) = self.fields.iter().position(|f| f.name.to_ident() == ident) {
1794 pub fn field_named(&self, name: ast::Name) -> &FieldDef {
1795 self.find_field_named(name).unwrap()
1799 impl<'a, 'gcx, 'tcx> FieldDef {
1800 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1801 tcx.type_of(self.did).subst(tcx, subst)
1805 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1806 pub enum ClosureKind {
1807 // Warning: Ordering is significant here! The ordering is chosen
1808 // because the trait Fn is a subtrait of FnMut and so in turn, and
1809 // hence we order it so that Fn < FnMut < FnOnce.
1815 impl<'a, 'tcx> ClosureKind {
1816 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
1818 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
1819 ClosureKind::FnMut => {
1820 tcx.require_lang_item(FnMutTraitLangItem)
1822 ClosureKind::FnOnce => {
1823 tcx.require_lang_item(FnOnceTraitLangItem)
1828 /// True if this a type that impls this closure kind
1829 /// must also implement `other`.
1830 pub fn extends(self, other: ty::ClosureKind) -> bool {
1831 match (self, other) {
1832 (ClosureKind::Fn, ClosureKind::Fn) => true,
1833 (ClosureKind::Fn, ClosureKind::FnMut) => true,
1834 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
1835 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
1836 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
1837 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
1843 impl<'tcx> TyS<'tcx> {
1844 /// Iterator that walks `self` and any types reachable from
1845 /// `self`, in depth-first order. Note that just walks the types
1846 /// that appear in `self`, it does not descend into the fields of
1847 /// structs or variants. For example:
1850 /// isize => { isize }
1851 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
1852 /// [isize] => { [isize], isize }
1854 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
1855 TypeWalker::new(self)
1858 /// Iterator that walks the immediate children of `self`. Hence
1859 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
1860 /// (but not `i32`, like `walk`).
1861 pub fn walk_shallow(&'tcx self) -> AccIntoIter<walk::TypeWalkerArray<'tcx>> {
1862 walk::walk_shallow(self)
1865 /// Walks `ty` and any types appearing within `ty`, invoking the
1866 /// callback `f` on each type. If the callback returns false, then the
1867 /// children of the current type are ignored.
1869 /// Note: prefer `ty.walk()` where possible.
1870 pub fn maybe_walk<F>(&'tcx self, mut f: F)
1871 where F : FnMut(Ty<'tcx>) -> bool
1873 let mut walker = self.walk();
1874 while let Some(ty) = walker.next() {
1876 walker.skip_current_subtree();
1882 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1883 pub enum LvaluePreference {
1888 impl LvaluePreference {
1889 pub fn from_mutbl(m: hir::Mutability) -> Self {
1891 hir::MutMutable => PreferMutLvalue,
1892 hir::MutImmutable => NoPreference,
1898 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
1900 hir::MutMutable => MutBorrow,
1901 hir::MutImmutable => ImmBorrow,
1905 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
1906 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
1907 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
1909 pub fn to_mutbl_lossy(self) -> hir::Mutability {
1911 MutBorrow => hir::MutMutable,
1912 ImmBorrow => hir::MutImmutable,
1914 // We have no type corresponding to a unique imm borrow, so
1915 // use `&mut`. It gives all the capabilities of an `&uniq`
1916 // and hence is a safe "over approximation".
1917 UniqueImmBorrow => hir::MutMutable,
1921 pub fn to_user_str(&self) -> &'static str {
1923 MutBorrow => "mutable",
1924 ImmBorrow => "immutable",
1925 UniqueImmBorrow => "uniquely immutable",
1930 #[derive(Debug, Clone)]
1931 pub enum Attributes<'gcx> {
1932 Owned(Rc<[ast::Attribute]>),
1933 Borrowed(&'gcx [ast::Attribute])
1936 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
1937 type Target = [ast::Attribute];
1939 fn deref(&self) -> &[ast::Attribute] {
1941 &Attributes::Owned(ref data) => &data,
1942 &Attributes::Borrowed(data) => data
1947 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
1948 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
1949 self.typeck_tables_of(self.hir.body_owner_def_id(body))
1952 /// Returns an iterator of the def-ids for all body-owners in this
1953 /// crate. If you would prefer to iterate over the bodies
1954 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
1955 pub fn body_owners(self) -> impl Iterator<Item = DefId> + 'a {
1959 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
1962 pub fn expr_span(self, id: NodeId) -> Span {
1963 match self.hir.find(id) {
1964 Some(hir_map::NodeExpr(e)) => {
1968 bug!("Node id {} is not an expr: {:?}", id, f);
1971 bug!("Node id {} is not present in the node map", id);
1976 pub fn local_var_name_str(self, id: NodeId) -> InternedString {
1977 match self.hir.find(id) {
1978 Some(hir_map::NodeLocal(pat)) => {
1980 hir::PatKind::Binding(_, _, ref path1, _) => path1.node.as_str(),
1982 bug!("Variable id {} maps to {:?}, not local", id, pat);
1986 r => bug!("Variable id {} maps to {:?}, not local", id, r),
1990 pub fn expr_is_lval(self, expr: &hir::Expr) -> bool {
1992 hir::ExprPath(hir::QPath::Resolved(_, ref path)) => {
1994 Def::Local(..) | Def::Upvar(..) | Def::Static(..) | Def::Err => true,
1999 hir::ExprType(ref e, _) => {
2000 self.expr_is_lval(e)
2003 hir::ExprUnary(hir::UnDeref, _) |
2004 hir::ExprField(..) |
2005 hir::ExprTupField(..) |
2006 hir::ExprIndex(..) => {
2010 // Partially qualified paths in expressions can only legally
2011 // refer to associated items which are always rvalues.
2012 hir::ExprPath(hir::QPath::TypeRelative(..)) |
2015 hir::ExprMethodCall(..) |
2016 hir::ExprStruct(..) |
2019 hir::ExprMatch(..) |
2020 hir::ExprClosure(..) |
2021 hir::ExprBlock(..) |
2022 hir::ExprRepeat(..) |
2023 hir::ExprArray(..) |
2024 hir::ExprBreak(..) |
2025 hir::ExprAgain(..) |
2027 hir::ExprWhile(..) |
2029 hir::ExprAssign(..) |
2030 hir::ExprInlineAsm(..) |
2031 hir::ExprAssignOp(..) |
2033 hir::ExprUnary(..) |
2035 hir::ExprAddrOf(..) |
2036 hir::ExprBinary(..) |
2037 hir::ExprCast(..) => {
2043 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2044 self.associated_items(id)
2045 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2049 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2050 self.associated_items(did).any(|item| {
2051 item.relevant_for_never()
2055 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2056 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2057 match self.hir.get(node_id) {
2058 hir_map::NodeTraitItem(_) | hir_map::NodeImplItem(_) => true,
2062 match self.describe_def(def_id).expect("no def for def-id") {
2063 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2068 if is_associated_item {
2069 Some(self.associated_item(def_id))
2075 fn associated_item_from_trait_item_ref(self,
2076 parent_def_id: DefId,
2077 parent_vis: &hir::Visibility,
2078 trait_item_ref: &hir::TraitItemRef)
2080 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2081 let (kind, has_self) = match trait_item_ref.kind {
2082 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2083 hir::AssociatedItemKind::Method { has_self } => {
2084 (ty::AssociatedKind::Method, has_self)
2086 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2090 name: trait_item_ref.name,
2092 // Visibility of trait items is inherited from their traits.
2093 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2094 defaultness: trait_item_ref.defaultness,
2096 container: TraitContainer(parent_def_id),
2097 method_has_self_argument: has_self
2101 fn associated_item_from_impl_item_ref(self,
2102 parent_def_id: DefId,
2103 impl_item_ref: &hir::ImplItemRef)
2105 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2106 let (kind, has_self) = match impl_item_ref.kind {
2107 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2108 hir::AssociatedItemKind::Method { has_self } => {
2109 (ty::AssociatedKind::Method, has_self)
2111 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2114 ty::AssociatedItem {
2115 name: impl_item_ref.name,
2117 // Visibility of trait impl items doesn't matter.
2118 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2119 defaultness: impl_item_ref.defaultness,
2121 container: ImplContainer(parent_def_id),
2122 method_has_self_argument: has_self
2126 #[inline] // FIXME(#35870) Avoid closures being unexported due to impl Trait.
2127 pub fn associated_items(self, def_id: DefId)
2128 -> impl Iterator<Item = ty::AssociatedItem> + 'a {
2129 let def_ids = self.associated_item_def_ids(def_id);
2130 (0..def_ids.len()).map(move |i| self.associated_item(def_ids[i]))
2133 /// Returns true if the impls are the same polarity and are implementing
2134 /// a trait which contains no items
2135 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2136 if !self.sess.features.borrow().overlapping_marker_traits {
2139 let trait1_is_empty = self.impl_trait_ref(def_id1)
2140 .map_or(false, |trait_ref| {
2141 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2143 let trait2_is_empty = self.impl_trait_ref(def_id2)
2144 .map_or(false, |trait_ref| {
2145 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2147 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2152 // Returns `ty::VariantDef` if `def` refers to a struct,
2153 // or variant or their constructors, panics otherwise.
2154 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2156 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2157 let enum_did = self.parent_def_id(did).unwrap();
2158 self.adt_def(enum_did).variant_with_id(did)
2160 Def::Struct(did) | Def::Union(did) => {
2161 self.adt_def(did).struct_variant()
2163 Def::StructCtor(ctor_did, ..) => {
2164 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2165 self.adt_def(did).struct_variant()
2167 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2171 pub fn def_key(self, id: DefId) -> hir_map::DefKey {
2173 self.hir.def_key(id)
2175 self.sess.cstore.def_key(id)
2179 /// Convert a `DefId` into its fully expanded `DefPath` (every
2180 /// `DefId` is really just an interned def-path).
2182 /// Note that if `id` is not local to this crate, the result will
2183 /// be a non-local `DefPath`.
2184 pub fn def_path(self, id: DefId) -> hir_map::DefPath {
2186 self.hir.def_path(id)
2188 self.sess.cstore.def_path(id)
2193 pub fn def_path_hash(self, def_id: DefId) -> ich::Fingerprint {
2194 if def_id.is_local() {
2195 self.hir.definitions().def_path_hash(def_id.index)
2197 self.sess.cstore.def_path_hash(def_id)
2201 pub fn item_name(self, id: DefId) -> ast::Name {
2202 if let Some(id) = self.hir.as_local_node_id(id) {
2204 } else if id.index == CRATE_DEF_INDEX {
2205 self.sess.cstore.original_crate_name(id.krate)
2207 let def_key = self.sess.cstore.def_key(id);
2208 // The name of a StructCtor is that of its struct parent.
2209 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2210 self.item_name(DefId {
2212 index: def_key.parent.unwrap()
2215 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2216 bug!("item_name: no name for {:?}", self.def_path(id));
2222 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2223 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2227 ty::InstanceDef::Item(did) => {
2228 self.optimized_mir(did)
2230 ty::InstanceDef::Intrinsic(..) |
2231 ty::InstanceDef::FnPtrShim(..) |
2232 ty::InstanceDef::Virtual(..) |
2233 ty::InstanceDef::ClosureOnceShim { .. } |
2234 ty::InstanceDef::DropGlue(..) => {
2235 self.mir_shims(instance)
2240 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2241 /// Returns None if there is no MIR for the DefId
2242 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2243 if self.is_mir_available(did) {
2244 Some(self.optimized_mir(did))
2250 /// Get the attributes of a definition.
2251 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2252 if let Some(id) = self.hir.as_local_node_id(did) {
2253 Attributes::Borrowed(self.hir.attrs(id))
2255 Attributes::Owned(self.item_attrs(did))
2259 /// Determine whether an item is annotated with an attribute
2260 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2261 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2264 pub fn trait_has_default_impl(self, trait_def_id: DefId) -> bool {
2265 self.trait_def(trait_def_id).has_default_impl
2268 /// Given the def_id of an impl, return the def_id of the trait it implements.
2269 /// If it implements no trait, return `None`.
2270 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2271 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2274 /// If the given def ID describes a method belonging to an impl, return the
2275 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2276 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2277 let item = if def_id.krate != LOCAL_CRATE {
2278 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2279 Some(self.associated_item(def_id))
2284 self.opt_associated_item(def_id)
2288 Some(trait_item) => {
2289 match trait_item.container {
2290 TraitContainer(_) => None,
2291 ImplContainer(def_id) => Some(def_id),
2298 pub fn node_scope_region(self, id: NodeId) -> Region<'tcx> {
2299 self.mk_region(ty::ReScope(CodeExtent::Misc(id)))
2302 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2303 /// with the name of the crate containing the impl.
2304 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2305 if impl_did.is_local() {
2306 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2307 Ok(self.hir.span(node_id))
2309 Err(self.sess.cstore.crate_name(impl_did.krate))
2313 pub fn adjust(self, name: Name, scope: DefId, block: NodeId) -> (Ident, DefId) {
2314 self.adjust_ident(name.to_ident(), scope, block)
2317 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
2318 let expansion = match scope.krate {
2319 LOCAL_CRATE => self.hir.definitions().expansion(scope.index),
2322 let scope = match ident.ctxt.adjust(expansion) {
2323 Some(macro_def) => self.hir.definitions().macro_def_scope(macro_def),
2324 None => self.hir.get_module_parent(block),
2330 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2331 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2332 F: FnOnce(&[hir::Freevar]) -> T,
2334 match self.freevars.borrow().get(&fid) {
2336 Some(d) => f(&d[..])
2341 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
2344 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2345 let parent_id = tcx.hir.get_parent(id);
2346 let parent_def_id = tcx.hir.local_def_id(parent_id);
2347 let parent_item = tcx.hir.expect_item(parent_id);
2348 match parent_item.node {
2349 hir::ItemImpl(.., ref impl_item_refs) => {
2350 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2351 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2353 debug_assert_eq!(assoc_item.def_id, def_id);
2358 hir::ItemTrait(.., ref trait_item_refs) => {
2359 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2360 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2363 debug_assert_eq!(assoc_item.def_id, def_id);
2371 span_bug!(parent_item.span,
2372 "unexpected parent of trait or impl item or item not found: {:?}",
2376 /// Calculates the Sized-constraint.
2378 /// In fact, there are only a few options for the types in the constraint:
2379 /// - an obviously-unsized type
2380 /// - a type parameter or projection whose Sizedness can't be known
2381 /// - a tuple of type parameters or projections, if there are multiple
2383 /// - a TyError, if a type contained itself. The representability
2384 /// check should catch this case.
2385 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2387 -> &'tcx [Ty<'tcx>] {
2388 let def = tcx.adt_def(def_id);
2390 let result = tcx.intern_type_list(&def.variants.iter().flat_map(|v| {
2393 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2394 }).collect::<Vec<_>>());
2396 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2401 /// Calculates the dtorck constraint for a type.
2402 fn adt_dtorck_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2404 -> DtorckConstraint<'tcx> {
2405 let def = tcx.adt_def(def_id);
2406 let span = tcx.def_span(def_id);
2407 debug!("dtorck_constraint: {:?}", def);
2409 if def.is_phantom_data() {
2410 let result = DtorckConstraint {
2413 tcx.mk_param_from_def(&tcx.generics_of(def_id).types[0])
2416 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2420 let mut result = def.all_fields()
2421 .map(|field| tcx.type_of(field.did))
2422 .map(|fty| tcx.dtorck_constraint_for_ty(span, fty, 0, fty))
2423 .collect::<Result<DtorckConstraint, ErrorReported>>()
2424 .unwrap_or(DtorckConstraint::empty());
2425 result.outlives.extend(tcx.destructor_constraints(def));
2428 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2433 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2436 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2437 let item = tcx.hir.expect_item(id);
2438 let vec: Vec<_> = match item.node {
2439 hir::ItemTrait(.., ref trait_item_refs) => {
2440 trait_item_refs.iter()
2441 .map(|trait_item_ref| trait_item_ref.id)
2442 .map(|id| tcx.hir.local_def_id(id.node_id))
2445 hir::ItemImpl(.., ref impl_item_refs) => {
2446 impl_item_refs.iter()
2447 .map(|impl_item_ref| impl_item_ref.id)
2448 .map(|id| tcx.hir.local_def_id(id.node_id))
2451 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2456 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
2457 tcx.hir.span_if_local(def_id).unwrap()
2460 /// If the given def ID describes an item belonging to a trait,
2461 /// return the ID of the trait that the trait item belongs to.
2462 /// Otherwise, return `None`.
2463 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
2464 tcx.opt_associated_item(def_id)
2465 .and_then(|associated_item| {
2466 match associated_item.container {
2467 TraitContainer(def_id) => Some(def_id),
2468 ImplContainer(_) => None
2473 /// See `ParamEnv` struct def'n for details.
2474 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2477 // Compute the bounds on Self and the type parameters.
2479 let bounds = tcx.predicates_of(def_id).instantiate_identity(tcx);
2480 let predicates = bounds.predicates;
2482 // Finally, we have to normalize the bounds in the environment, in
2483 // case they contain any associated type projections. This process
2484 // can yield errors if the put in illegal associated types, like
2485 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2486 // report these errors right here; this doesn't actually feel
2487 // right to me, because constructing the environment feels like a
2488 // kind of a "idempotent" action, but I'm not sure where would be
2489 // a better place. In practice, we construct environments for
2490 // every fn once during type checking, and we'll abort if there
2491 // are any errors at that point, so after type checking you can be
2492 // sure that this will succeed without errors anyway.
2494 let unnormalized_env = ty::ParamEnv::new(tcx.intern_predicates(&predicates),
2495 traits::Reveal::UserFacing);
2497 let body_id = tcx.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
2498 tcx.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_id)
2500 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
2501 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
2504 pub fn provide(providers: &mut ty::maps::Providers) {
2505 util::provide(providers);
2506 *providers = ty::maps::Providers {
2508 associated_item_def_ids,
2509 adt_sized_constraint,
2510 adt_dtorck_constraint,
2514 trait_impls_of: trait_def::trait_impls_of_provider,
2515 relevant_trait_impls_for: trait_def::relevant_trait_impls_provider,
2520 pub fn provide_extern(providers: &mut ty::maps::Providers) {
2521 *providers = ty::maps::Providers {
2522 adt_sized_constraint,
2523 adt_dtorck_constraint,
2524 trait_impls_of: trait_def::trait_impls_of_provider,
2525 relevant_trait_impls_for: trait_def::relevant_trait_impls_provider,
2532 /// A map for the local crate mapping each type to a vector of its
2533 /// inherent impls. This is not meant to be used outside of coherence;
2534 /// rather, you should request the vector for a specific type via
2535 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2536 /// (constructing this map requires touching the entire crate).
2537 #[derive(Clone, Debug)]
2538 pub struct CrateInherentImpls {
2539 pub inherent_impls: DefIdMap<Rc<Vec<DefId>>>,
2542 /// A set of constraints that need to be satisfied in order for
2543 /// a type to be valid for destruction.
2544 #[derive(Clone, Debug)]
2545 pub struct DtorckConstraint<'tcx> {
2546 /// Types that are required to be alive in order for this
2547 /// type to be valid for destruction.
2548 pub outlives: Vec<ty::subst::Kind<'tcx>>,
2549 /// Types that could not be resolved: projections and params.
2550 pub dtorck_types: Vec<Ty<'tcx>>,
2553 impl<'tcx> FromIterator<DtorckConstraint<'tcx>> for DtorckConstraint<'tcx>
2555 fn from_iter<I: IntoIterator<Item=DtorckConstraint<'tcx>>>(iter: I) -> Self {
2556 let mut result = Self::empty();
2558 for constraint in iter {
2559 result.outlives.extend(constraint.outlives);
2560 result.dtorck_types.extend(constraint.dtorck_types);
2568 impl<'tcx> DtorckConstraint<'tcx> {
2569 fn empty() -> DtorckConstraint<'tcx> {
2572 dtorck_types: vec![]
2576 fn dedup<'a>(&mut self) {
2577 let mut outlives = FxHashSet();
2578 let mut dtorck_types = FxHashSet();
2580 self.outlives.retain(|&val| outlives.replace(val).is_none());
2581 self.dtorck_types.retain(|&val| dtorck_types.replace(val).is_none());
2585 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord)]
2586 pub struct SymbolName {
2587 // FIXME: we don't rely on interning or equality here - better have
2588 // this be a `&'tcx str`.
2589 pub name: InternedString
2592 impl Deref for SymbolName {
2595 fn deref(&self) -> &str { &self.name }
2598 impl fmt::Display for SymbolName {
2599 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2600 fmt::Display::fmt(&self.name, fmt)