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::fold::TypeFoldable;
17 use hir::{map as hir_map, FreevarMap, TraitMap};
18 use hir::def::{Def, CtorKind, ExportMap};
19 use hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
20 use hir::map::DefPathData;
23 use ich::StableHashingContext;
24 use infer::canonical::{Canonical, Canonicalize};
25 use middle::const_val::ConstVal;
26 use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
27 use middle::privacy::AccessLevels;
28 use middle::resolve_lifetime::ObjectLifetimeDefault;
30 use mir::interpret::{GlobalId, Value, PrimVal};
31 use mir::GeneratorLayout;
32 use session::CrateDisambiguator;
33 use traits::{self, Reveal};
35 use ty::subst::{Subst, Substs};
36 use ty::util::{IntTypeExt, Discr};
37 use ty::walk::TypeWalker;
38 use util::captures::Captures;
39 use util::nodemap::{NodeSet, DefIdMap, FxHashMap};
41 use serialize::{self, Encodable, Encoder};
42 use std::cell::RefCell;
45 use std::hash::{Hash, Hasher};
47 use rustc_data_structures::sync::Lrc;
49 use std::vec::IntoIter;
51 use syntax::ast::{self, DUMMY_NODE_ID, Name, Ident, NodeId};
53 use syntax::ext::hygiene::Mark;
54 use syntax::symbol::{Symbol, InternedString};
55 use syntax_pos::{DUMMY_SP, Span};
57 use rustc_data_structures::accumulate_vec::IntoIter as AccIntoIter;
58 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
63 pub use self::sty::{Binder, CanonicalVar, DebruijnIndex};
64 pub use self::sty::{FnSig, GenSig, PolyFnSig, PolyGenSig};
65 pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
66 pub use self::sty::{ClosureSubsts, GeneratorInterior, TypeAndMut};
67 pub use self::sty::{TraitRef, TypeVariants, PolyTraitRef};
68 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
69 pub use self::sty::{ExistentialProjection, PolyExistentialProjection, Const};
70 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
71 pub use self::sty::RegionKind;
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::binding::BindingMode;
79 pub use self::binding::BindingMode::*;
81 pub use self::context::{TyCtxt, GlobalArenas, AllArenas, tls, keep_local};
82 pub use self::context::{Lift, TypeckTables, InterpretInterner};
84 pub use self::instance::{Instance, InstanceDef};
86 pub use self::trait_def::TraitDef;
88 pub use self::maps::queries;
99 pub mod inhabitedness;
116 mod structural_impls;
121 /// The complete set of all analyses described in this module. This is
122 /// produced by the driver and fed to trans and later passes.
124 /// NB: These contents are being migrated into queries using the
125 /// *on-demand* infrastructure.
127 pub struct CrateAnalysis {
128 pub access_levels: Lrc<AccessLevels>,
130 pub glob_map: Option<hir::GlobMap>,
134 pub struct Resolutions {
135 pub freevars: FreevarMap,
136 pub trait_map: TraitMap,
137 pub maybe_unused_trait_imports: NodeSet,
138 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
139 pub export_map: ExportMap,
142 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
143 pub enum AssociatedItemContainer {
144 TraitContainer(DefId),
145 ImplContainer(DefId),
148 impl AssociatedItemContainer {
149 /// Asserts that this is the def-id of an associated item declared
150 /// in a trait, and returns the trait def-id.
151 pub fn assert_trait(&self) -> DefId {
153 TraitContainer(id) => id,
154 _ => bug!("associated item has wrong container type: {:?}", self)
158 pub fn id(&self) -> DefId {
160 TraitContainer(id) => id,
161 ImplContainer(id) => id,
166 /// The "header" of an impl is everything outside the body: a Self type, a trait
167 /// ref (in the case of a trait impl), and a set of predicates (from the
168 /// bounds/where clauses).
169 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
170 pub struct ImplHeader<'tcx> {
171 pub impl_def_id: DefId,
172 pub self_ty: Ty<'tcx>,
173 pub trait_ref: Option<TraitRef<'tcx>>,
174 pub predicates: Vec<Predicate<'tcx>>,
177 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
178 pub struct AssociatedItem {
181 pub kind: AssociatedKind,
183 pub defaultness: hir::Defaultness,
184 pub container: AssociatedItemContainer,
186 /// Whether this is a method with an explicit self
187 /// as its first argument, allowing method calls.
188 pub method_has_self_argument: bool,
191 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash, RustcEncodable, RustcDecodable)]
192 pub enum AssociatedKind {
198 impl AssociatedItem {
199 pub fn def(&self) -> Def {
201 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
202 AssociatedKind::Method => Def::Method(self.def_id),
203 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
207 /// Tests whether the associated item admits a non-trivial implementation
209 pub fn relevant_for_never<'tcx>(&self) -> bool {
211 AssociatedKind::Const => true,
212 AssociatedKind::Type => true,
213 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
214 AssociatedKind::Method => !self.method_has_self_argument,
218 pub fn signature<'a, 'tcx>(&self, tcx: &TyCtxt<'a, 'tcx, 'tcx>) -> String {
220 ty::AssociatedKind::Method => {
221 // We skip the binder here because the binder would deanonymize all
222 // late-bound regions, and we don't want method signatures to show up
223 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
224 // regions just fine, showing `fn(&MyType)`.
225 format!("{}", tcx.fn_sig(self.def_id).skip_binder())
227 ty::AssociatedKind::Type => format!("type {};", self.name.to_string()),
228 ty::AssociatedKind::Const => {
229 format!("const {}: {:?};", self.name.to_string(), tcx.type_of(self.def_id))
235 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
236 pub enum Visibility {
237 /// Visible everywhere (including in other crates).
239 /// Visible only in the given crate-local module.
241 /// Not visible anywhere in the local crate. This is the visibility of private external items.
245 pub trait DefIdTree: Copy {
246 fn parent(self, id: DefId) -> Option<DefId>;
248 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
249 if descendant.krate != ancestor.krate {
253 while descendant != ancestor {
254 match self.parent(descendant) {
255 Some(parent) => descendant = parent,
256 None => return false,
263 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
264 fn parent(self, id: DefId) -> Option<DefId> {
265 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
270 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt) -> Self {
272 hir::Public => Visibility::Public,
273 hir::Visibility::Crate => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
274 hir::Visibility::Restricted { ref path, .. } => match path.def {
275 // If there is no resolution, `resolve` will have already reported an error, so
276 // assume that the visibility is public to avoid reporting more privacy errors.
277 Def::Err => Visibility::Public,
278 def => Visibility::Restricted(def.def_id()),
281 Visibility::Restricted(tcx.hir.get_module_parent(id))
286 /// Returns true if an item with this visibility is accessible from the given block.
287 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
288 let restriction = match self {
289 // Public items are visible everywhere.
290 Visibility::Public => return true,
291 // Private items from other crates are visible nowhere.
292 Visibility::Invisible => return false,
293 // Restricted items are visible in an arbitrary local module.
294 Visibility::Restricted(other) if other.krate != module.krate => return false,
295 Visibility::Restricted(module) => module,
298 tree.is_descendant_of(module, restriction)
301 /// Returns true if this visibility is at least as accessible as the given visibility
302 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
303 let vis_restriction = match vis {
304 Visibility::Public => return self == Visibility::Public,
305 Visibility::Invisible => return true,
306 Visibility::Restricted(module) => module,
309 self.is_accessible_from(vis_restriction, tree)
312 // Returns true if this item is visible anywhere in the local crate.
313 pub fn is_visible_locally(self) -> bool {
315 Visibility::Public => true,
316 Visibility::Restricted(def_id) => def_id.is_local(),
317 Visibility::Invisible => false,
322 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
324 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
325 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
326 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
327 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
330 /// The crate variances map is computed during typeck and contains the
331 /// variance of every item in the local crate. You should not use it
332 /// directly, because to do so will make your pass dependent on the
333 /// HIR of every item in the local crate. Instead, use
334 /// `tcx.variances_of()` to get the variance for a *particular*
336 pub struct CrateVariancesMap {
337 /// For each item with generics, maps to a vector of the variance
338 /// of its generics. If an item has no generics, it will have no
340 pub variances: FxHashMap<DefId, Lrc<Vec<ty::Variance>>>,
342 /// An empty vector, useful for cloning.
343 pub empty_variance: Lrc<Vec<ty::Variance>>,
347 /// `a.xform(b)` combines the variance of a context with the
348 /// variance of a type with the following meaning. If we are in a
349 /// context with variance `a`, and we encounter a type argument in
350 /// a position with variance `b`, then `a.xform(b)` is the new
351 /// variance with which the argument appears.
357 /// Here, the "ambient" variance starts as covariant. `*mut T` is
358 /// invariant with respect to `T`, so the variance in which the
359 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
360 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
361 /// respect to its type argument `T`, and hence the variance of
362 /// the `i32` here is `Invariant.xform(Covariant)`, which results
363 /// (again) in `Invariant`.
367 /// fn(*const Vec<i32>, *mut Vec<i32)
369 /// The ambient variance is covariant. A `fn` type is
370 /// contravariant with respect to its parameters, so the variance
371 /// within which both pointer types appear is
372 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
373 /// T` is covariant with respect to `T`, so the variance within
374 /// which the first `Vec<i32>` appears is
375 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
376 /// is true for its `i32` argument. In the `*mut T` case, the
377 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
378 /// and hence the outermost type is `Invariant` with respect to
379 /// `Vec<i32>` (and its `i32` argument).
381 /// Source: Figure 1 of "Taming the Wildcards:
382 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
383 pub fn xform(self, v: ty::Variance) -> ty::Variance {
385 // Figure 1, column 1.
386 (ty::Covariant, ty::Covariant) => ty::Covariant,
387 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
388 (ty::Covariant, ty::Invariant) => ty::Invariant,
389 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
391 // Figure 1, column 2.
392 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
393 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
394 (ty::Contravariant, ty::Invariant) => ty::Invariant,
395 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
397 // Figure 1, column 3.
398 (ty::Invariant, _) => ty::Invariant,
400 // Figure 1, column 4.
401 (ty::Bivariant, _) => ty::Bivariant,
406 // Contains information needed to resolve types and (in the future) look up
407 // the types of AST nodes.
408 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
409 pub struct CReaderCacheKey {
414 // Flags that we track on types. These flags are propagated upwards
415 // through the type during type construction, so that we can quickly
416 // check whether the type has various kinds of types in it without
417 // recursing over the type itself.
419 pub struct TypeFlags: u32 {
420 const HAS_PARAMS = 1 << 0;
421 const HAS_SELF = 1 << 1;
422 const HAS_TY_INFER = 1 << 2;
423 const HAS_RE_INFER = 1 << 3;
424 const HAS_RE_SKOL = 1 << 4;
426 /// Does this have any `ReEarlyBound` regions? Used to
427 /// determine whether substitition is required, since those
428 /// represent regions that are bound in a `ty::Generics` and
429 /// hence may be substituted.
430 const HAS_RE_EARLY_BOUND = 1 << 5;
432 /// Does this have any region that "appears free" in the type?
433 /// Basically anything but `ReLateBound` and `ReErased`.
434 const HAS_FREE_REGIONS = 1 << 6;
436 /// Is an error type reachable?
437 const HAS_TY_ERR = 1 << 7;
438 const HAS_PROJECTION = 1 << 8;
440 // FIXME: Rename this to the actual property since it's used for generators too
441 const HAS_TY_CLOSURE = 1 << 9;
443 // true if there are "names" of types and regions and so forth
444 // that are local to a particular fn
445 const HAS_LOCAL_NAMES = 1 << 10;
447 // Present if the type belongs in a local type context.
448 // Only set for TyInfer other than Fresh.
449 const KEEP_IN_LOCAL_TCX = 1 << 11;
451 // Is there a projection that does not involve a bound region?
452 // Currently we can't normalize projections w/ bound regions.
453 const HAS_NORMALIZABLE_PROJECTION = 1 << 12;
455 // Set if this includes a "canonical" type or region var --
456 // ought to be true only for the results of canonicalization.
457 const HAS_CANONICAL_VARS = 1 << 13;
459 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
460 TypeFlags::HAS_SELF.bits |
461 TypeFlags::HAS_RE_EARLY_BOUND.bits;
463 // Flags representing the nominal content of a type,
464 // computed by FlagsComputation. If you add a new nominal
465 // flag, it should be added here too.
466 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
467 TypeFlags::HAS_SELF.bits |
468 TypeFlags::HAS_TY_INFER.bits |
469 TypeFlags::HAS_RE_INFER.bits |
470 TypeFlags::HAS_RE_SKOL.bits |
471 TypeFlags::HAS_RE_EARLY_BOUND.bits |
472 TypeFlags::HAS_FREE_REGIONS.bits |
473 TypeFlags::HAS_TY_ERR.bits |
474 TypeFlags::HAS_PROJECTION.bits |
475 TypeFlags::HAS_TY_CLOSURE.bits |
476 TypeFlags::HAS_LOCAL_NAMES.bits |
477 TypeFlags::KEEP_IN_LOCAL_TCX.bits |
478 TypeFlags::HAS_CANONICAL_VARS.bits;
482 pub struct TyS<'tcx> {
483 pub sty: TypeVariants<'tcx>,
484 pub flags: TypeFlags,
486 // the maximal depth of any bound regions appearing in this type.
490 impl<'tcx> PartialEq for TyS<'tcx> {
492 fn eq(&self, other: &TyS<'tcx>) -> bool {
493 // (self as *const _) == (other as *const _)
494 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
497 impl<'tcx> Eq for TyS<'tcx> {}
499 impl<'tcx> Hash for TyS<'tcx> {
500 fn hash<H: Hasher>(&self, s: &mut H) {
501 (self as *const TyS).hash(s)
505 impl<'tcx> TyS<'tcx> {
506 pub fn is_primitive_ty(&self) -> bool {
508 TypeVariants::TyBool |
509 TypeVariants::TyChar |
510 TypeVariants::TyInt(_) |
511 TypeVariants::TyUint(_) |
512 TypeVariants::TyFloat(_) |
513 TypeVariants::TyInfer(InferTy::IntVar(_)) |
514 TypeVariants::TyInfer(InferTy::FloatVar(_)) |
515 TypeVariants::TyInfer(InferTy::FreshIntTy(_)) |
516 TypeVariants::TyInfer(InferTy::FreshFloatTy(_)) => true,
517 TypeVariants::TyRef(_, x) => x.ty.is_primitive_ty(),
522 pub fn is_suggestable(&self) -> bool {
524 TypeVariants::TyAnon(..) |
525 TypeVariants::TyFnDef(..) |
526 TypeVariants::TyFnPtr(..) |
527 TypeVariants::TyDynamic(..) |
528 TypeVariants::TyClosure(..) |
529 TypeVariants::TyInfer(..) |
530 TypeVariants::TyProjection(..) => false,
536 impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for ty::TyS<'gcx> {
537 fn hash_stable<W: StableHasherResult>(&self,
538 hcx: &mut StableHashingContext<'a>,
539 hasher: &mut StableHasher<W>) {
543 // The other fields just provide fast access to information that is
544 // also contained in `sty`, so no need to hash them.
549 sty.hash_stable(hcx, hasher);
553 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
555 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
556 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
558 pub type CanonicalTy<'gcx> = Canonical<'gcx, Ty<'gcx>>;
560 impl <'gcx: 'tcx, 'tcx> Canonicalize<'gcx, 'tcx> for Ty<'tcx> {
561 type Canonicalized = CanonicalTy<'gcx>;
563 fn intern(_gcx: TyCtxt<'_, 'gcx, 'gcx>,
564 value: Canonical<'gcx, Self::Lifted>) -> Self::Canonicalized {
569 /// A wrapper for slices with the additional invariant
570 /// that the slice is interned and no other slice with
571 /// the same contents can exist in the same context.
572 /// This means we can use pointer + length for both
573 /// equality comparisons and hashing.
574 #[derive(Debug, RustcEncodable)]
575 pub struct Slice<T>([T]);
577 impl<T> PartialEq for Slice<T> {
579 fn eq(&self, other: &Slice<T>) -> bool {
580 (&self.0 as *const [T]) == (&other.0 as *const [T])
583 impl<T> Eq for Slice<T> {}
585 impl<T> Hash for Slice<T> {
586 fn hash<H: Hasher>(&self, s: &mut H) {
587 (self.as_ptr(), self.len()).hash(s)
591 impl<T> Deref for Slice<T> {
593 fn deref(&self) -> &[T] {
598 impl<'a, T> IntoIterator for &'a Slice<T> {
600 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
601 fn into_iter(self) -> Self::IntoIter {
606 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {}
609 pub fn empty<'a>() -> &'a Slice<T> {
611 mem::transmute(slice::from_raw_parts(0x1 as *const T, 0))
616 /// Upvars do not get their own node-id. Instead, we use the pair of
617 /// the original var id (that is, the root variable that is referenced
618 /// by the upvar) and the id of the closure expression.
619 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
621 pub var_id: hir::HirId,
622 pub closure_expr_id: LocalDefId,
625 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
626 pub enum BorrowKind {
627 /// Data must be immutable and is aliasable.
630 /// Data must be immutable but not aliasable. This kind of borrow
631 /// cannot currently be expressed by the user and is used only in
632 /// implicit closure bindings. It is needed when the closure
633 /// is borrowing or mutating a mutable referent, e.g.:
635 /// let x: &mut isize = ...;
636 /// let y = || *x += 5;
638 /// If we were to try to translate this closure into a more explicit
639 /// form, we'd encounter an error with the code as written:
641 /// struct Env { x: & &mut isize }
642 /// let x: &mut isize = ...;
643 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
644 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
646 /// This is then illegal because you cannot mutate a `&mut` found
647 /// in an aliasable location. To solve, you'd have to translate with
648 /// an `&mut` borrow:
650 /// struct Env { x: & &mut isize }
651 /// let x: &mut isize = ...;
652 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
653 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
655 /// Now the assignment to `**env.x` is legal, but creating a
656 /// mutable pointer to `x` is not because `x` is not mutable. We
657 /// could fix this by declaring `x` as `let mut x`. This is ok in
658 /// user code, if awkward, but extra weird for closures, since the
659 /// borrow is hidden.
661 /// So we introduce a "unique imm" borrow -- the referent is
662 /// immutable, but not aliasable. This solves the problem. For
663 /// simplicity, we don't give users the way to express this
664 /// borrow, it's just used when translating closures.
667 /// Data is mutable and not aliasable.
671 /// Information describing the capture of an upvar. This is computed
672 /// during `typeck`, specifically by `regionck`.
673 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
674 pub enum UpvarCapture<'tcx> {
675 /// Upvar is captured by value. This is always true when the
676 /// closure is labeled `move`, but can also be true in other cases
677 /// depending on inference.
680 /// Upvar is captured by reference.
681 ByRef(UpvarBorrow<'tcx>),
684 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
685 pub struct UpvarBorrow<'tcx> {
686 /// The kind of borrow: by-ref upvars have access to shared
687 /// immutable borrows, which are not part of the normal language
689 pub kind: BorrowKind,
691 /// Region of the resulting reference.
692 pub region: ty::Region<'tcx>,
695 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
697 #[derive(Copy, Clone)]
698 pub struct ClosureUpvar<'tcx> {
704 #[derive(Clone, Copy, PartialEq, Eq)]
705 pub enum IntVarValue {
707 UintType(ast::UintTy),
710 #[derive(Clone, Copy, PartialEq, Eq)]
711 pub struct FloatVarValue(pub ast::FloatTy);
713 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
714 pub struct TypeParameterDef {
715 pub name: InternedString,
718 pub has_default: bool,
719 pub object_lifetime_default: ObjectLifetimeDefault,
721 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
722 /// on generic parameter `T`, asserts data behind the parameter
723 /// `T` won't be accessed during the parent type's `Drop` impl.
724 pub pure_wrt_drop: bool,
726 pub synthetic: Option<hir::SyntheticTyParamKind>,
729 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
730 pub struct RegionParameterDef {
731 pub name: InternedString,
735 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
736 /// on generic parameter `'a`, asserts data of lifetime `'a`
737 /// won't be accessed during the parent type's `Drop` impl.
738 pub pure_wrt_drop: bool,
741 impl RegionParameterDef {
742 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
743 ty::EarlyBoundRegion {
750 pub fn to_bound_region(&self) -> ty::BoundRegion {
751 self.to_early_bound_region_data().to_bound_region()
755 impl ty::EarlyBoundRegion {
756 pub fn to_bound_region(&self) -> ty::BoundRegion {
757 ty::BoundRegion::BrNamed(self.def_id, self.name)
761 /// Information about the formal type/lifetime parameters associated
762 /// with an item or method. Analogous to hir::Generics.
764 /// Note that in the presence of a `Self` parameter, the ordering here
765 /// is different from the ordering in a Substs. Substs are ordered as
766 /// Self, *Regions, *Other Type Params, (...child generics)
767 /// while this struct is ordered as
768 /// regions = Regions
769 /// types = [Self, *Other Type Params]
770 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
771 pub struct Generics {
772 pub parent: Option<DefId>,
773 pub parent_regions: u32,
774 pub parent_types: u32,
775 pub regions: Vec<RegionParameterDef>,
776 pub types: Vec<TypeParameterDef>,
778 /// Reverse map to each `TypeParameterDef`'s `index` field
779 pub type_param_to_index: FxHashMap<DefId, u32>,
782 pub has_late_bound_regions: Option<Span>,
785 impl<'a, 'gcx, 'tcx> Generics {
786 pub fn parent_count(&self) -> usize {
787 self.parent_regions as usize + self.parent_types as usize
790 pub fn own_count(&self) -> usize {
791 self.regions.len() + self.types.len()
794 pub fn count(&self) -> usize {
795 self.parent_count() + self.own_count()
798 pub fn region_param(&'tcx self,
799 param: &EarlyBoundRegion,
800 tcx: TyCtxt<'a, 'gcx, 'tcx>)
801 -> &'tcx RegionParameterDef
803 if let Some(index) = param.index.checked_sub(self.parent_count() as u32) {
804 &self.regions[index as usize - self.has_self as usize]
806 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
807 .region_param(param, tcx)
811 /// Returns the `TypeParameterDef` associated with this `ParamTy`.
812 pub fn type_param(&'tcx self,
814 tcx: TyCtxt<'a, 'gcx, 'tcx>)
815 -> &TypeParameterDef {
816 if let Some(idx) = param.idx.checked_sub(self.parent_count() as u32) {
817 // non-Self type parameters are always offset by exactly
818 // `self.regions.len()`. In the absence of a Self, this is obvious,
819 // but even in the presence of a `Self` we just have to "compensate"
822 // Without a `Self` (or in a nested generics that doesn't have
823 // a `Self` in itself, even through it parent does), for example
824 // for `fn foo<'a, T1, T2>()`, the situation is:
832 // And with a `Self`, for example for `trait Foo<'a, 'b, T1, T2>`, the
841 // And it can be seen that in both cases, to move from a substs
842 // offset to a generics offset you just have to offset by the
843 // number of regions.
844 let type_param_offset = self.regions.len();
846 let has_self = self.has_self && self.parent.is_none();
847 let is_separated_self = type_param_offset != 0 && idx == 0 && has_self;
849 if let Some(idx) = (idx as usize).checked_sub(type_param_offset) {
850 assert!(!is_separated_self, "found a Self after type_param_offset");
853 assert!(is_separated_self, "non-Self param before type_param_offset");
857 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
858 .type_param(param, tcx)
863 /// Bounds on generics.
864 #[derive(Clone, Default)]
865 pub struct GenericPredicates<'tcx> {
866 pub parent: Option<DefId>,
867 pub predicates: Vec<Predicate<'tcx>>,
870 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
871 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
873 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
874 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
875 -> InstantiatedPredicates<'tcx> {
876 let mut instantiated = InstantiatedPredicates::empty();
877 self.instantiate_into(tcx, &mut instantiated, substs);
880 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
881 -> InstantiatedPredicates<'tcx> {
882 InstantiatedPredicates {
883 predicates: self.predicates.subst(tcx, substs)
887 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
888 instantiated: &mut InstantiatedPredicates<'tcx>,
889 substs: &Substs<'tcx>) {
890 if let Some(def_id) = self.parent {
891 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
893 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
896 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
897 -> InstantiatedPredicates<'tcx> {
898 let mut instantiated = InstantiatedPredicates::empty();
899 self.instantiate_identity_into(tcx, &mut instantiated);
903 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
904 instantiated: &mut InstantiatedPredicates<'tcx>) {
905 if let Some(def_id) = self.parent {
906 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
908 instantiated.predicates.extend(&self.predicates)
911 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
912 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
913 -> InstantiatedPredicates<'tcx>
915 assert_eq!(self.parent, None);
916 InstantiatedPredicates {
917 predicates: self.predicates.iter().map(|pred| {
918 pred.subst_supertrait(tcx, poly_trait_ref)
924 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
925 pub enum Predicate<'tcx> {
926 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
927 /// the `Self` type of the trait reference and `A`, `B`, and `C`
928 /// would be the type parameters.
929 Trait(PolyTraitPredicate<'tcx>),
932 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
935 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
937 /// where <T as TraitRef>::Name == X, approximately.
938 /// See `ProjectionPredicate` struct for details.
939 Projection(PolyProjectionPredicate<'tcx>),
942 WellFormed(Ty<'tcx>),
944 /// trait must be object-safe
947 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
948 /// for some substitutions `...` and T being a closure type.
949 /// Satisfied (or refuted) once we know the closure's kind.
950 ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
953 Subtype(PolySubtypePredicate<'tcx>),
955 /// Constant initializer must evaluate successfully.
956 ConstEvaluatable(DefId, &'tcx Substs<'tcx>),
959 /// The crate outlives map is computed during typeck and contains the
960 /// outlives of every item in the local crate. You should not use it
961 /// directly, because to do so will make your pass dependent on the
962 /// HIR of every item in the local crate. Instead, use
963 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
965 pub struct CratePredicatesMap<'tcx> {
966 /// For each struct with outlive bounds, maps to a vector of the
967 /// predicate of its outlive bounds. If an item has no outlives
968 /// bounds, it will have no entry.
969 pub predicates: FxHashMap<DefId, Lrc<Vec<ty::Predicate<'tcx>>>>,
971 /// An empty vector, useful for cloning.
972 pub empty_predicate: Lrc<Vec<ty::Predicate<'tcx>>>,
975 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
976 fn as_ref(&self) -> &Predicate<'tcx> {
981 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
982 /// Performs a substitution suitable for going from a
983 /// poly-trait-ref to supertraits that must hold if that
984 /// poly-trait-ref holds. This is slightly different from a normal
985 /// substitution in terms of what happens with bound regions. See
986 /// lengthy comment below for details.
987 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
988 trait_ref: &ty::PolyTraitRef<'tcx>)
989 -> ty::Predicate<'tcx>
991 // The interaction between HRTB and supertraits is not entirely
992 // obvious. Let me walk you (and myself) through an example.
994 // Let's start with an easy case. Consider two traits:
996 // trait Foo<'a> : Bar<'a,'a> { }
997 // trait Bar<'b,'c> { }
999 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
1000 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
1001 // knew that `Foo<'x>` (for any 'x) then we also know that
1002 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1003 // normal substitution.
1005 // In terms of why this is sound, the idea is that whenever there
1006 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1007 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1008 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1011 // Another example to be careful of is this:
1013 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
1014 // trait Bar1<'b,'c> { }
1016 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
1017 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
1018 // reason is similar to the previous example: any impl of
1019 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
1020 // basically we would want to collapse the bound lifetimes from
1021 // the input (`trait_ref`) and the supertraits.
1023 // To achieve this in practice is fairly straightforward. Let's
1024 // consider the more complicated scenario:
1026 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
1027 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
1028 // where both `'x` and `'b` would have a DB index of 1.
1029 // The substitution from the input trait-ref is therefore going to be
1030 // `'a => 'x` (where `'x` has a DB index of 1).
1031 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1032 // early-bound parameter and `'b' is a late-bound parameter with a
1034 // - If we replace `'a` with `'x` from the input, it too will have
1035 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1036 // just as we wanted.
1038 // There is only one catch. If we just apply the substitution `'a
1039 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1040 // adjust the DB index because we substituting into a binder (it
1041 // tries to be so smart...) resulting in `for<'x> for<'b>
1042 // Bar1<'x,'b>` (we have no syntax for this, so use your
1043 // imagination). Basically the 'x will have DB index of 2 and 'b
1044 // will have DB index of 1. Not quite what we want. So we apply
1045 // the substitution to the *contents* of the trait reference,
1046 // rather than the trait reference itself (put another way, the
1047 // substitution code expects equal binding levels in the values
1048 // from the substitution and the value being substituted into, and
1049 // this trick achieves that).
1051 let substs = &trait_ref.skip_binder().substs;
1053 Predicate::Trait(ref binder) =>
1054 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1055 Predicate::Subtype(ref binder) =>
1056 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1057 Predicate::RegionOutlives(ref binder) =>
1058 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1059 Predicate::TypeOutlives(ref binder) =>
1060 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1061 Predicate::Projection(ref binder) =>
1062 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1063 Predicate::WellFormed(data) =>
1064 Predicate::WellFormed(data.subst(tcx, substs)),
1065 Predicate::ObjectSafe(trait_def_id) =>
1066 Predicate::ObjectSafe(trait_def_id),
1067 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1068 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1069 Predicate::ConstEvaluatable(def_id, const_substs) =>
1070 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1075 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1076 pub struct TraitPredicate<'tcx> {
1077 pub trait_ref: TraitRef<'tcx>
1079 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1081 impl<'tcx> TraitPredicate<'tcx> {
1082 pub fn def_id(&self) -> DefId {
1083 self.trait_ref.def_id
1086 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
1087 self.trait_ref.input_types()
1090 pub fn self_ty(&self) -> Ty<'tcx> {
1091 self.trait_ref.self_ty()
1095 impl<'tcx> PolyTraitPredicate<'tcx> {
1096 pub fn def_id(&self) -> DefId {
1097 // ok to skip binder since trait def-id does not care about regions
1098 self.skip_binder().def_id()
1102 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1103 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
1104 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1105 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>,
1107 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>,
1109 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1110 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1112 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1113 pub struct SubtypePredicate<'tcx> {
1114 pub a_is_expected: bool,
1118 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1120 /// This kind of predicate has no *direct* correspondent in the
1121 /// syntax, but it roughly corresponds to the syntactic forms:
1123 /// 1. `T : TraitRef<..., Item=Type>`
1124 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1126 /// In particular, form #1 is "desugared" to the combination of a
1127 /// normal trait predicate (`T : TraitRef<...>`) and one of these
1128 /// predicates. Form #2 is a broader form in that it also permits
1129 /// equality between arbitrary types. Processing an instance of
1130 /// Form #2 eventually yields one of these `ProjectionPredicate`
1131 /// instances to normalize the LHS.
1132 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1133 pub struct ProjectionPredicate<'tcx> {
1134 pub projection_ty: ProjectionTy<'tcx>,
1138 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1140 impl<'tcx> PolyProjectionPredicate<'tcx> {
1141 /// Returns the def-id of the associated item being projected.
1142 pub fn item_def_id(&self) -> DefId {
1143 self.skip_binder().projection_ty.item_def_id
1146 pub fn to_poly_trait_ref(&self, tcx: TyCtxt) -> PolyTraitRef<'tcx> {
1147 // Note: unlike with TraitRef::to_poly_trait_ref(),
1148 // self.0.trait_ref is permitted to have escaping regions.
1149 // This is because here `self` has a `Binder` and so does our
1150 // return value, so we are preserving the number of binding
1152 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1155 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1156 self.map_bound(|predicate| predicate.ty)
1159 /// The DefId of the TraitItem for the associated type.
1161 /// Note that this is not the DefId of the TraitRef containing this
1162 /// associated type, which is in tcx.associated_item(projection_def_id()).container.
1163 pub fn projection_def_id(&self) -> DefId {
1164 // ok to skip binder since trait def-id does not care about regions
1165 self.skip_binder().projection_ty.item_def_id
1169 pub trait ToPolyTraitRef<'tcx> {
1170 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1173 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1174 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1175 ty::Binder::dummy(self.clone())
1179 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1180 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1181 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1185 pub trait ToPredicate<'tcx> {
1186 fn to_predicate(&self) -> Predicate<'tcx>;
1189 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1190 fn to_predicate(&self) -> Predicate<'tcx> {
1191 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1192 trait_ref: self.clone()
1197 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1198 fn to_predicate(&self) -> Predicate<'tcx> {
1199 ty::Predicate::Trait(self.to_poly_trait_predicate())
1203 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1204 fn to_predicate(&self) -> Predicate<'tcx> {
1205 Predicate::RegionOutlives(self.clone())
1209 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1210 fn to_predicate(&self) -> Predicate<'tcx> {
1211 Predicate::TypeOutlives(self.clone())
1215 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1216 fn to_predicate(&self) -> Predicate<'tcx> {
1217 Predicate::Projection(self.clone())
1221 impl<'tcx> Predicate<'tcx> {
1222 /// Iterates over the types in this predicate. Note that in all
1223 /// cases this is skipping over a binder, so late-bound regions
1224 /// with depth 0 are bound by the predicate.
1225 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1226 let vec: Vec<_> = match *self {
1227 ty::Predicate::Trait(ref data) => {
1228 data.skip_binder().input_types().collect()
1230 ty::Predicate::Subtype(binder) => {
1231 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1234 ty::Predicate::TypeOutlives(binder) => {
1235 vec![binder.skip_binder().0]
1237 ty::Predicate::RegionOutlives(..) => {
1240 ty::Predicate::Projection(ref data) => {
1241 let inner = data.skip_binder();
1242 inner.projection_ty.substs.types().chain(Some(inner.ty)).collect()
1244 ty::Predicate::WellFormed(data) => {
1247 ty::Predicate::ObjectSafe(_trait_def_id) => {
1250 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1251 closure_substs.substs.types().collect()
1253 ty::Predicate::ConstEvaluatable(_, substs) => {
1254 substs.types().collect()
1258 // The only reason to collect into a vector here is that I was
1259 // too lazy to make the full (somewhat complicated) iterator
1260 // type that would be needed here. But I wanted this fn to
1261 // return an iterator conceptually, rather than a `Vec`, so as
1262 // to be closer to `Ty::walk`.
1266 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1268 Predicate::Trait(ref t) => {
1269 Some(t.to_poly_trait_ref())
1271 Predicate::Projection(..) |
1272 Predicate::Subtype(..) |
1273 Predicate::RegionOutlives(..) |
1274 Predicate::WellFormed(..) |
1275 Predicate::ObjectSafe(..) |
1276 Predicate::ClosureKind(..) |
1277 Predicate::TypeOutlives(..) |
1278 Predicate::ConstEvaluatable(..) => {
1284 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1286 Predicate::TypeOutlives(data) => {
1289 Predicate::Trait(..) |
1290 Predicate::Projection(..) |
1291 Predicate::Subtype(..) |
1292 Predicate::RegionOutlives(..) |
1293 Predicate::WellFormed(..) |
1294 Predicate::ObjectSafe(..) |
1295 Predicate::ClosureKind(..) |
1296 Predicate::ConstEvaluatable(..) => {
1303 /// Represents the bounds declared on a particular set of type
1304 /// parameters. Should eventually be generalized into a flag list of
1305 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1306 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1307 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1308 /// the `GenericPredicates` are expressed in terms of the bound type
1309 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1310 /// represented a set of bounds for some particular instantiation,
1311 /// meaning that the generic parameters have been substituted with
1316 /// struct Foo<T,U:Bar<T>> { ... }
1318 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1319 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1320 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1321 /// [usize:Bar<isize>]]`.
1323 pub struct InstantiatedPredicates<'tcx> {
1324 pub predicates: Vec<Predicate<'tcx>>,
1327 impl<'tcx> InstantiatedPredicates<'tcx> {
1328 pub fn empty() -> InstantiatedPredicates<'tcx> {
1329 InstantiatedPredicates { predicates: vec![] }
1332 pub fn is_empty(&self) -> bool {
1333 self.predicates.is_empty()
1337 /// "Universes" are used during type- and trait-checking in the
1338 /// presence of `for<..>` binders to control what sets of names are
1339 /// visible. Universes are arranged into a tree: the root universe
1340 /// contains names that are always visible. But when you enter into
1341 /// some subuniverse, then it may add names that are only visible
1342 /// within that subtree (but it can still name the names of its
1343 /// ancestor universes).
1345 /// To make this more concrete, consider this program:
1349 /// fn bar<T>(x: T) {
1350 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1354 /// The struct name `Foo` is in the root universe U0. But the type
1355 /// parameter `T`, introduced on `bar`, is in a subuniverse U1 --
1356 /// i.e., within `bar`, we can name both `T` and `Foo`, but outside of
1357 /// `bar`, we cannot name `T`. Then, within the type of `y`, the
1358 /// region `'a` is in a subuniverse U2 of U1, because we can name it
1359 /// inside the fn type but not outside.
1361 /// Universes are related to **skolemization** -- which is a way of
1362 /// doing type- and trait-checking around these "forall" binders (also
1363 /// called **universal quantification**). The idea is that when, in
1364 /// the body of `bar`, we refer to `T` as a type, we aren't referring
1365 /// to any type in particular, but rather a kind of "fresh" type that
1366 /// is distinct from all other types we have actually declared. This
1367 /// is called a **skolemized** type, and we use universes to talk
1368 /// about this. In other words, a type name in universe 0 always
1369 /// corresponds to some "ground" type that the user declared, but a
1370 /// type name in a non-zero universe is a skolemized type -- an
1371 /// idealized representative of "types in general" that we use for
1372 /// checking generic functions.
1373 #[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
1374 pub struct UniverseIndex(u32);
1376 impl UniverseIndex {
1377 /// The root universe, where things that the user defined are
1379 pub fn root() -> UniverseIndex {
1383 /// A "subuniverse" corresponds to being inside a `forall` quantifier.
1384 /// So, for example, suppose we have this type in universe `U`:
1387 /// for<'a> fn(&'a u32)
1390 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1391 /// subuniverse of `U` -- in this new universe, we can name the
1392 /// region `'a`, but that region was not nameable from `U` because
1393 /// it was not in scope there.
1394 pub fn subuniverse(self) -> UniverseIndex {
1395 UniverseIndex(self.0 + 1)
1399 /// When type checking, we use the `ParamEnv` to track
1400 /// details about the set of where-clauses that are in scope at this
1401 /// particular point.
1402 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1403 pub struct ParamEnv<'tcx> {
1404 /// Obligations that the caller must satisfy. This is basically
1405 /// the set of bounds on the in-scope type parameters, translated
1406 /// into Obligations, and elaborated and normalized.
1407 pub caller_bounds: &'tcx Slice<ty::Predicate<'tcx>>,
1409 /// Typically, this is `Reveal::UserFacing`, but during trans we
1410 /// want `Reveal::All` -- note that this is always paired with an
1411 /// empty environment. To get that, use `ParamEnv::reveal()`.
1412 pub reveal: traits::Reveal,
1415 impl<'tcx> ParamEnv<'tcx> {
1416 /// Construct a trait environment suitable for contexts where
1417 /// there are no where clauses in scope. Hidden types (like `impl
1418 /// Trait`) are left hidden, so this is suitable for ordinary
1420 pub fn empty() -> Self {
1421 Self::new(ty::Slice::empty(), Reveal::UserFacing)
1424 /// Construct a trait environment with no where clauses in scope
1425 /// where the values of all `impl Trait` and other hidden types
1426 /// are revealed. This is suitable for monomorphized, post-typeck
1427 /// environments like trans or doing optimizations.
1429 /// NB. If you want to have predicates in scope, use `ParamEnv::new`,
1430 /// or invoke `param_env.with_reveal_all()`.
1431 pub fn reveal_all() -> Self {
1432 Self::new(ty::Slice::empty(), Reveal::All)
1435 /// Construct a trait environment with the given set of predicates.
1436 pub fn new(caller_bounds: &'tcx ty::Slice<ty::Predicate<'tcx>>,
1439 ty::ParamEnv { caller_bounds, reveal }
1442 /// Returns a new parameter environment with the same clauses, but
1443 /// which "reveals" the true results of projections in all cases
1444 /// (even for associated types that are specializable). This is
1445 /// the desired behavior during trans and certain other special
1446 /// contexts; normally though we want to use `Reveal::UserFacing`,
1447 /// which is the default.
1448 pub fn with_reveal_all(self) -> Self {
1449 ty::ParamEnv { reveal: Reveal::All, ..self }
1452 /// Returns this same environment but with no caller bounds.
1453 pub fn without_caller_bounds(self) -> Self {
1454 ty::ParamEnv { caller_bounds: ty::Slice::empty(), ..self }
1457 /// Creates a suitable environment in which to perform trait
1458 /// queries on the given value. When type-checking, this is simply
1459 /// the pair of the environment plus value. But when reveal is set to
1460 /// All, then if `value` does not reference any type parameters, we will
1461 /// pair it with the empty environment. This improves caching and is generally
1464 /// NB: We preserve the environment when type-checking because it
1465 /// is possible for the user to have wacky where-clauses like
1466 /// `where Box<u32>: Copy`, which are clearly never
1467 /// satisfiable. We generally want to behave as if they were true,
1468 /// although the surrounding function is never reachable.
1469 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1471 Reveal::UserFacing => {
1479 if value.needs_infer() || value.has_param_types() || value.has_self_ty() {
1486 param_env: self.without_caller_bounds(),
1495 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1496 pub struct ParamEnvAnd<'tcx, T> {
1497 pub param_env: ParamEnv<'tcx>,
1501 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1502 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1503 (self.param_env, self.value)
1507 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'gcx, T>
1508 where T: HashStable<StableHashingContext<'a>>
1510 fn hash_stable<W: StableHasherResult>(&self,
1511 hcx: &mut StableHashingContext<'a>,
1512 hasher: &mut StableHasher<W>) {
1518 param_env.hash_stable(hcx, hasher);
1519 value.hash_stable(hcx, hasher);
1523 #[derive(Copy, Clone, Debug)]
1524 pub struct Destructor {
1525 /// The def-id of the destructor method
1530 pub struct AdtFlags: u32 {
1531 const NO_ADT_FLAGS = 0;
1532 const IS_ENUM = 1 << 0;
1533 const IS_PHANTOM_DATA = 1 << 1;
1534 const IS_FUNDAMENTAL = 1 << 2;
1535 const IS_UNION = 1 << 3;
1536 const IS_BOX = 1 << 4;
1537 /// Indicates whether this abstract data type will be expanded on in future (new
1538 /// fields/variants) and as such, whether downstream crates must match exhaustively on the
1539 /// fields/variants of this data type.
1541 /// See RFC 2008 (<https://github.com/rust-lang/rfcs/pull/2008>).
1542 const IS_NON_EXHAUSTIVE = 1 << 5;
1547 pub struct VariantDef {
1548 /// The variant's DefId. If this is a tuple-like struct,
1549 /// this is the DefId of the struct's ctor.
1551 pub name: Name, // struct's name if this is a struct
1552 pub discr: VariantDiscr,
1553 pub fields: Vec<FieldDef>,
1554 pub ctor_kind: CtorKind,
1557 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1558 pub enum VariantDiscr {
1559 /// Explicit value for this variant, i.e. `X = 123`.
1560 /// The `DefId` corresponds to the embedded constant.
1563 /// The previous variant's discriminant plus one.
1564 /// For efficiency reasons, the distance from the
1565 /// last `Explicit` discriminant is being stored,
1566 /// or `0` for the first variant, if it has none.
1571 pub struct FieldDef {
1574 pub vis: Visibility,
1577 /// The definition of an abstract data type - a struct or enum.
1579 /// These are all interned (by intern_adt_def) into the adt_defs
1583 pub variants: Vec<VariantDef>,
1585 pub repr: ReprOptions,
1588 impl PartialEq for AdtDef {
1589 // AdtDef are always interned and this is part of TyS equality
1591 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1594 impl Eq for AdtDef {}
1596 impl Hash for AdtDef {
1598 fn hash<H: Hasher>(&self, s: &mut H) {
1599 (self as *const AdtDef).hash(s)
1603 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1604 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1609 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1612 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1613 fn hash_stable<W: StableHasherResult>(&self,
1614 hcx: &mut StableHashingContext<'a>,
1615 hasher: &mut StableHasher<W>) {
1617 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> =
1618 RefCell::new(FxHashMap());
1621 let hash: Fingerprint = CACHE.with(|cache| {
1622 let addr = self as *const AdtDef as usize;
1623 *cache.borrow_mut().entry(addr).or_insert_with(|| {
1631 let mut hasher = StableHasher::new();
1632 did.hash_stable(hcx, &mut hasher);
1633 variants.hash_stable(hcx, &mut hasher);
1634 flags.hash_stable(hcx, &mut hasher);
1635 repr.hash_stable(hcx, &mut hasher);
1641 hash.hash_stable(hcx, hasher);
1645 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
1646 pub enum AdtKind { Struct, Union, Enum }
1649 #[derive(RustcEncodable, RustcDecodable, Default)]
1650 pub struct ReprFlags: u8 {
1651 const IS_C = 1 << 0;
1652 const IS_SIMD = 1 << 1;
1653 const IS_TRANSPARENT = 1 << 2;
1654 // Internal only for now. If true, don't reorder fields.
1655 const IS_LINEAR = 1 << 3;
1657 // Any of these flags being set prevent field reordering optimisation.
1658 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1659 ReprFlags::IS_SIMD.bits |
1660 ReprFlags::IS_LINEAR.bits;
1664 impl_stable_hash_for!(struct ReprFlags {
1670 /// Represents the repr options provided by the user,
1671 #[derive(Copy, Clone, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1672 pub struct ReprOptions {
1673 pub int: Option<attr::IntType>,
1676 pub flags: ReprFlags,
1679 impl_stable_hash_for!(struct ReprOptions {
1687 pub fn new(tcx: TyCtxt, did: DefId) -> ReprOptions {
1688 let mut flags = ReprFlags::empty();
1689 let mut size = None;
1690 let mut max_align = 0;
1691 let mut min_pack = 0;
1692 for attr in tcx.get_attrs(did).iter() {
1693 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1694 flags.insert(match r {
1695 attr::ReprC => ReprFlags::IS_C,
1696 attr::ReprPacked(pack) => {
1697 min_pack = if min_pack > 0 {
1698 cmp::min(pack, min_pack)
1704 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
1705 attr::ReprSimd => ReprFlags::IS_SIMD,
1706 attr::ReprInt(i) => {
1710 attr::ReprAlign(align) => {
1711 max_align = cmp::max(align, max_align);
1718 // This is here instead of layout because the choice must make it into metadata.
1719 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1720 flags.insert(ReprFlags::IS_LINEAR);
1722 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
1726 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1728 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1730 pub fn packed(&self) -> bool { self.pack > 0 }
1732 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
1734 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1736 pub fn discr_type(&self) -> attr::IntType {
1737 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
1740 /// Returns true if this `#[repr()]` should inhabit "smart enum
1741 /// layout" optimizations, such as representing `Foo<&T>` as a
1743 pub fn inhibit_enum_layout_opt(&self) -> bool {
1744 self.c() || self.int.is_some()
1747 /// Returns true if this `#[repr()]` should inhibit struct field reordering
1748 /// optimizations, such as with repr(C) or repr(packed(1)).
1749 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
1750 !(self.flags & ReprFlags::IS_UNOPTIMISABLE).is_empty() || (self.pack == 1)
1754 impl<'a, 'gcx, 'tcx> AdtDef {
1758 variants: Vec<VariantDef>,
1759 repr: ReprOptions) -> Self {
1760 let mut flags = AdtFlags::NO_ADT_FLAGS;
1761 let attrs = tcx.get_attrs(did);
1762 if attr::contains_name(&attrs, "fundamental") {
1763 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1765 if Some(did) == tcx.lang_items().phantom_data() {
1766 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1768 if Some(did) == tcx.lang_items().owned_box() {
1769 flags = flags | AdtFlags::IS_BOX;
1771 if tcx.has_attr(did, "non_exhaustive") {
1772 flags = flags | AdtFlags::IS_NON_EXHAUSTIVE;
1775 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
1776 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
1777 AdtKind::Struct => {}
1788 pub fn is_struct(&self) -> bool {
1789 !self.is_union() && !self.is_enum()
1793 pub fn is_union(&self) -> bool {
1794 self.flags.intersects(AdtFlags::IS_UNION)
1798 pub fn is_enum(&self) -> bool {
1799 self.flags.intersects(AdtFlags::IS_ENUM)
1803 pub fn is_non_exhaustive(&self) -> bool {
1804 self.flags.intersects(AdtFlags::IS_NON_EXHAUSTIVE)
1807 /// Returns the kind of the ADT - Struct or Enum.
1809 pub fn adt_kind(&self) -> AdtKind {
1812 } else if self.is_union() {
1819 pub fn descr(&self) -> &'static str {
1820 match self.adt_kind() {
1821 AdtKind::Struct => "struct",
1822 AdtKind::Union => "union",
1823 AdtKind::Enum => "enum",
1827 pub fn variant_descr(&self) -> &'static str {
1828 match self.adt_kind() {
1829 AdtKind::Struct => "struct",
1830 AdtKind::Union => "union",
1831 AdtKind::Enum => "variant",
1835 /// Returns whether this type is #[fundamental] for the purposes
1836 /// of coherence checking.
1838 pub fn is_fundamental(&self) -> bool {
1839 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
1842 /// Returns true if this is PhantomData<T>.
1844 pub fn is_phantom_data(&self) -> bool {
1845 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
1848 /// Returns true if this is Box<T>.
1850 pub fn is_box(&self) -> bool {
1851 self.flags.intersects(AdtFlags::IS_BOX)
1854 /// Returns whether this type has a destructor.
1855 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
1856 self.destructor(tcx).is_some()
1859 /// Asserts this is a struct or union and returns its unique variant.
1860 pub fn non_enum_variant(&self) -> &VariantDef {
1861 assert!(self.is_struct() || self.is_union());
1866 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
1867 tcx.predicates_of(self.did)
1870 /// Returns an iterator over all fields contained
1873 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
1874 self.variants.iter().flat_map(|v| v.fields.iter())
1877 pub fn is_payloadfree(&self) -> bool {
1878 !self.variants.is_empty() &&
1879 self.variants.iter().all(|v| v.fields.is_empty())
1882 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
1885 .find(|v| v.did == vid)
1886 .expect("variant_with_id: unknown variant")
1889 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1892 .position(|v| v.did == vid)
1893 .expect("variant_index_with_id: unknown variant")
1896 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
1898 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
1899 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
1900 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.non_enum_variant(),
1901 _ => bug!("unexpected def {:?} in variant_of_def", def)
1906 pub fn eval_explicit_discr(
1908 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1910 ) -> Option<Discr<'tcx>> {
1911 let param_env = ParamEnv::empty();
1912 let repr_type = self.repr.discr_type();
1913 let substs = Substs::identity_for_item(tcx.global_tcx(), expr_did);
1914 let instance = ty::Instance::new(expr_did, substs);
1915 let cid = GlobalId {
1919 match tcx.const_eval(param_env.and(cid)) {
1921 val: ConstVal::Value(Value::ByVal(PrimVal::Bytes(b))),
1924 trace!("discriminants: {} ({:?})", b, repr_type);
1931 val: ConstVal::Value(other),
1934 info!("invalid enum discriminant: {:#?}", other);
1935 ::middle::const_val::struct_error(
1937 tcx.def_span(expr_did),
1938 "constant evaluation of enum discriminant resulted in non-integer",
1943 err.report(tcx, tcx.def_span(expr_did), "enum discriminant");
1944 if !expr_did.is_local() {
1945 span_bug!(tcx.def_span(expr_did),
1946 "variant discriminant evaluation succeeded \
1947 in its crate but failed locally");
1951 _ => span_bug!(tcx.def_span(expr_did), "const eval "),
1956 pub fn discriminants(
1958 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1959 ) -> impl Iterator<Item=Discr<'tcx>> + Captures<'gcx> + 'a {
1960 let repr_type = self.repr.discr_type();
1961 let initial = repr_type.initial_discriminant(tcx.global_tcx());
1962 let mut prev_discr = None::<Discr<'tcx>>;
1963 self.variants.iter().map(move |v| {
1964 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
1965 if let VariantDiscr::Explicit(expr_did) = v.discr {
1966 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
1970 prev_discr = Some(discr);
1976 /// Compute the discriminant value used by a specific variant.
1977 /// Unlike `discriminants`, this is (amortized) constant-time,
1978 /// only doing at most one query for evaluating an explicit
1979 /// discriminant (the last one before the requested variant),
1980 /// assuming there are no constant-evaluation errors there.
1981 pub fn discriminant_for_variant(&self,
1982 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1983 variant_index: usize)
1985 let (val, offset) = self.discriminant_def_for_variant(variant_index);
1986 let explicit_value = val
1987 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
1988 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx.global_tcx()));
1989 explicit_value.checked_add(tcx, offset as u128).0
1992 /// Yields a DefId for the discriminant and an offset to add to it
1993 /// Alternatively, if there is no explicit discriminant, returns the
1994 /// inferred discriminant directly
1995 pub fn discriminant_def_for_variant(
1997 variant_index: usize,
1998 ) -> (Option<DefId>, usize) {
1999 let mut explicit_index = variant_index;
2002 match self.variants[explicit_index].discr {
2003 ty::VariantDiscr::Relative(0) => {
2007 ty::VariantDiscr::Relative(distance) => {
2008 explicit_index -= distance;
2010 ty::VariantDiscr::Explicit(did) => {
2011 expr_did = Some(did);
2016 (expr_did, variant_index - explicit_index)
2019 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
2020 tcx.adt_destructor(self.did)
2023 /// Returns a list of types such that `Self: Sized` if and only
2024 /// if that type is Sized, or `TyErr` if this type is recursive.
2026 /// Oddly enough, checking that the sized-constraint is Sized is
2027 /// actually more expressive than checking all members:
2028 /// the Sized trait is inductive, so an associated type that references
2029 /// Self would prevent its containing ADT from being Sized.
2031 /// Due to normalization being eager, this applies even if
2032 /// the associated type is behind a pointer, e.g. issue #31299.
2033 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
2034 match tcx.try_get_query::<queries::adt_sized_constraint>(DUMMY_SP, self.did) {
2037 debug!("adt_sized_constraint: {:?} is recursive", self);
2038 // This should be reported as an error by `check_representable`.
2040 // Consider the type as Sized in the meanwhile to avoid
2041 // further errors. Delay our `bug` diagnostic here to get
2042 // emitted later as well in case we accidentally otherwise don't
2045 tcx.intern_type_list(&[tcx.types.err])
2050 fn sized_constraint_for_ty(&self,
2051 tcx: TyCtxt<'a, 'tcx, 'tcx>,
2054 let result = match ty.sty {
2055 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
2056 TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
2057 TyArray(..) | TyClosure(..) | TyGenerator(..) | TyNever => {
2066 TyGeneratorWitness(..) => {
2067 // these are never sized - return the target type
2071 TyTuple(ref tys) => {
2074 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
2078 TyAdt(adt, substs) => {
2080 let adt_tys = adt.sized_constraint(tcx);
2081 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
2084 .map(|ty| ty.subst(tcx, substs))
2085 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2089 TyProjection(..) | TyAnon(..) => {
2090 // must calculate explicitly.
2091 // FIXME: consider special-casing always-Sized projections
2096 // perf hack: if there is a `T: Sized` bound, then
2097 // we know that `T` is Sized and do not need to check
2100 let sized_trait = match tcx.lang_items().sized_trait() {
2102 _ => return vec![ty]
2104 let sized_predicate = Binder::dummy(TraitRef {
2105 def_id: sized_trait,
2106 substs: tcx.mk_substs_trait(ty, &[])
2108 let predicates = tcx.predicates_of(self.did).predicates;
2109 if predicates.into_iter().any(|p| p == sized_predicate) {
2117 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2121 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2126 impl<'a, 'gcx, 'tcx> FieldDef {
2127 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
2128 tcx.type_of(self.did).subst(tcx, subst)
2132 /// Represents the various closure traits in the Rust language. This
2133 /// will determine the type of the environment (`self`, in the
2134 /// desuaring) argument that the closure expects.
2136 /// You can get the environment type of a closure using
2137 /// `tcx.closure_env_ty()`.
2138 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
2139 pub enum ClosureKind {
2140 // Warning: Ordering is significant here! The ordering is chosen
2141 // because the trait Fn is a subtrait of FnMut and so in turn, and
2142 // hence we order it so that Fn < FnMut < FnOnce.
2148 impl<'a, 'tcx> ClosureKind {
2149 // This is the initial value used when doing upvar inference.
2150 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2152 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
2154 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
2155 ClosureKind::FnMut => {
2156 tcx.require_lang_item(FnMutTraitLangItem)
2158 ClosureKind::FnOnce => {
2159 tcx.require_lang_item(FnOnceTraitLangItem)
2164 /// True if this a type that impls this closure kind
2165 /// must also implement `other`.
2166 pub fn extends(self, other: ty::ClosureKind) -> bool {
2167 match (self, other) {
2168 (ClosureKind::Fn, ClosureKind::Fn) => true,
2169 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2170 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2171 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2172 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2173 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2178 /// Returns the representative scalar type for this closure kind.
2179 /// See `TyS::to_opt_closure_kind` for more details.
2180 pub fn to_ty(self, tcx: TyCtxt<'_, '_, 'tcx>) -> Ty<'tcx> {
2182 ty::ClosureKind::Fn => tcx.types.i8,
2183 ty::ClosureKind::FnMut => tcx.types.i16,
2184 ty::ClosureKind::FnOnce => tcx.types.i32,
2189 impl<'tcx> TyS<'tcx> {
2190 /// Iterator that walks `self` and any types reachable from
2191 /// `self`, in depth-first order. Note that just walks the types
2192 /// that appear in `self`, it does not descend into the fields of
2193 /// structs or variants. For example:
2196 /// isize => { isize }
2197 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2198 /// [isize] => { [isize], isize }
2200 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2201 TypeWalker::new(self)
2204 /// Iterator that walks the immediate children of `self`. Hence
2205 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2206 /// (but not `i32`, like `walk`).
2207 pub fn walk_shallow(&'tcx self) -> AccIntoIter<walk::TypeWalkerArray<'tcx>> {
2208 walk::walk_shallow(self)
2211 /// Walks `ty` and any types appearing within `ty`, invoking the
2212 /// callback `f` on each type. If the callback returns false, then the
2213 /// children of the current type are ignored.
2215 /// Note: prefer `ty.walk()` where possible.
2216 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2217 where F : FnMut(Ty<'tcx>) -> bool
2219 let mut walker = self.walk();
2220 while let Some(ty) = walker.next() {
2222 walker.skip_current_subtree();
2229 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2231 hir::MutMutable => MutBorrow,
2232 hir::MutImmutable => ImmBorrow,
2236 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2237 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2238 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2240 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2242 MutBorrow => hir::MutMutable,
2243 ImmBorrow => hir::MutImmutable,
2245 // We have no type corresponding to a unique imm borrow, so
2246 // use `&mut`. It gives all the capabilities of an `&uniq`
2247 // and hence is a safe "over approximation".
2248 UniqueImmBorrow => hir::MutMutable,
2252 pub fn to_user_str(&self) -> &'static str {
2254 MutBorrow => "mutable",
2255 ImmBorrow => "immutable",
2256 UniqueImmBorrow => "uniquely immutable",
2261 #[derive(Debug, Clone)]
2262 pub enum Attributes<'gcx> {
2263 Owned(Lrc<[ast::Attribute]>),
2264 Borrowed(&'gcx [ast::Attribute])
2267 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2268 type Target = [ast::Attribute];
2270 fn deref(&self) -> &[ast::Attribute] {
2272 &Attributes::Owned(ref data) => &data,
2273 &Attributes::Borrowed(data) => data
2278 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2279 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2280 self.typeck_tables_of(self.hir.body_owner_def_id(body))
2283 /// Returns an iterator of the def-ids for all body-owners in this
2284 /// crate. If you would prefer to iterate over the bodies
2285 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
2288 ) -> impl Iterator<Item = DefId> + Captures<'tcx> + Captures<'gcx> + 'a {
2292 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
2295 pub fn expr_span(self, id: NodeId) -> Span {
2296 match self.hir.find(id) {
2297 Some(hir_map::NodeExpr(e)) => {
2301 bug!("Node id {} is not an expr: {:?}", id, f);
2304 bug!("Node id {} is not present in the node map", id);
2309 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2310 self.associated_items(id)
2311 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2315 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2316 self.associated_items(did).any(|item| {
2317 item.relevant_for_never()
2321 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2322 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2323 match self.hir.get(node_id) {
2324 hir_map::NodeTraitItem(_) | hir_map::NodeImplItem(_) => true,
2328 match self.describe_def(def_id).expect("no def for def-id") {
2329 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2334 if is_associated_item {
2335 Some(self.associated_item(def_id))
2341 fn associated_item_from_trait_item_ref(self,
2342 parent_def_id: DefId,
2343 parent_vis: &hir::Visibility,
2344 trait_item_ref: &hir::TraitItemRef)
2346 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2347 let (kind, has_self) = match trait_item_ref.kind {
2348 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2349 hir::AssociatedItemKind::Method { has_self } => {
2350 (ty::AssociatedKind::Method, has_self)
2352 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2356 name: trait_item_ref.name,
2358 // Visibility of trait items is inherited from their traits.
2359 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2360 defaultness: trait_item_ref.defaultness,
2362 container: TraitContainer(parent_def_id),
2363 method_has_self_argument: has_self
2367 fn associated_item_from_impl_item_ref(self,
2368 parent_def_id: DefId,
2369 impl_item_ref: &hir::ImplItemRef)
2371 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2372 let (kind, has_self) = match impl_item_ref.kind {
2373 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2374 hir::AssociatedItemKind::Method { has_self } => {
2375 (ty::AssociatedKind::Method, has_self)
2377 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2380 ty::AssociatedItem {
2381 name: impl_item_ref.name,
2383 // Visibility of trait impl items doesn't matter.
2384 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2385 defaultness: impl_item_ref.defaultness,
2387 container: ImplContainer(parent_def_id),
2388 method_has_self_argument: has_self
2392 pub fn field_index(self, node_id: NodeId, tables: &TypeckTables) -> usize {
2393 let hir_id = self.hir.node_to_hir_id(node_id);
2394 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2397 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2398 variant.fields.iter().position(|field| {
2399 self.adjust_ident(ident.modern(), variant.did, DUMMY_NODE_ID).0 == field.name.to_ident()
2403 pub fn associated_items(
2406 ) -> impl Iterator<Item = ty::AssociatedItem> + 'a {
2407 let def_ids = self.associated_item_def_ids(def_id);
2408 Box::new((0..def_ids.len()).map(move |i| self.associated_item(def_ids[i])))
2409 as Box<dyn Iterator<Item = ty::AssociatedItem> + 'a>
2412 /// Returns true if the impls are the same polarity and are implementing
2413 /// a trait which contains no items
2414 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2415 if !self.features().overlapping_marker_traits {
2418 let trait1_is_empty = self.impl_trait_ref(def_id1)
2419 .map_or(false, |trait_ref| {
2420 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2422 let trait2_is_empty = self.impl_trait_ref(def_id2)
2423 .map_or(false, |trait_ref| {
2424 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2426 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2431 // Returns `ty::VariantDef` if `def` refers to a struct,
2432 // or variant or their constructors, panics otherwise.
2433 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2435 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2436 let enum_did = self.parent_def_id(did).unwrap();
2437 self.adt_def(enum_did).variant_with_id(did)
2439 Def::Struct(did) | Def::Union(did) => {
2440 self.adt_def(did).non_enum_variant()
2442 Def::StructCtor(ctor_did, ..) => {
2443 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2444 self.adt_def(did).non_enum_variant()
2446 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2450 /// Given a `VariantDef`, returns the def-id of the `AdtDef` of which it is a part.
2451 pub fn adt_def_id_of_variant(self, variant_def: &'tcx VariantDef) -> DefId {
2452 let def_key = self.def_key(variant_def.did);
2453 match def_key.disambiguated_data.data {
2454 // for enum variants and tuple structs, the def-id of the ADT itself
2455 // is the *parent* of the variant
2456 DefPathData::EnumVariant(..) | DefPathData::StructCtor =>
2457 DefId { krate: variant_def.did.krate, index: def_key.parent.unwrap() },
2459 // otherwise, for structs and unions, they share a def-id
2460 _ => variant_def.did,
2464 pub fn item_name(self, id: DefId) -> InternedString {
2465 if id.index == CRATE_DEF_INDEX {
2466 self.original_crate_name(id.krate).as_str()
2468 let def_key = self.def_key(id);
2469 // The name of a StructCtor is that of its struct parent.
2470 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2471 self.item_name(DefId {
2473 index: def_key.parent.unwrap()
2476 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2477 bug!("item_name: no name for {:?}", self.def_path(id));
2483 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2484 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2488 ty::InstanceDef::Item(did) => {
2489 self.optimized_mir(did)
2491 ty::InstanceDef::Intrinsic(..) |
2492 ty::InstanceDef::FnPtrShim(..) |
2493 ty::InstanceDef::Virtual(..) |
2494 ty::InstanceDef::ClosureOnceShim { .. } |
2495 ty::InstanceDef::DropGlue(..) |
2496 ty::InstanceDef::CloneShim(..) => {
2497 self.mir_shims(instance)
2502 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2503 /// Returns None if there is no MIR for the DefId
2504 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2505 if self.is_mir_available(did) {
2506 Some(self.optimized_mir(did))
2512 /// Get the attributes of a definition.
2513 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2514 if let Some(id) = self.hir.as_local_node_id(did) {
2515 Attributes::Borrowed(self.hir.attrs(id))
2517 Attributes::Owned(self.item_attrs(did))
2521 /// Determine whether an item is annotated with an attribute
2522 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2523 attr::contains_name(&self.get_attrs(did), attr)
2526 /// Returns true if this is an `auto trait`.
2527 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
2528 self.trait_def(trait_def_id).has_auto_impl
2531 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
2532 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
2535 /// Given the def_id of an impl, return the def_id of the trait it implements.
2536 /// If it implements no trait, return `None`.
2537 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2538 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2541 /// If the given def ID describes a method belonging to an impl, return the
2542 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2543 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2544 let item = if def_id.krate != LOCAL_CRATE {
2545 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2546 Some(self.associated_item(def_id))
2551 self.opt_associated_item(def_id)
2555 Some(trait_item) => {
2556 match trait_item.container {
2557 TraitContainer(_) => None,
2558 ImplContainer(def_id) => Some(def_id),
2565 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2566 /// with the name of the crate containing the impl.
2567 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2568 if impl_did.is_local() {
2569 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2570 Ok(self.hir.span(node_id))
2572 Err(self.crate_name(impl_did.krate))
2576 // Hygienically compare a use-site name (`use_name`) for a field or an associated item with its
2577 // supposed definition name (`def_name`). The method also needs `DefId` of the supposed
2578 // definition's parent/scope to perform comparison.
2579 pub fn hygienic_eq(self, use_name: Name, def_name: Name, def_parent_def_id: DefId) -> bool {
2580 self.adjust(use_name, def_parent_def_id, DUMMY_NODE_ID).0 == def_name.to_ident()
2583 pub fn adjust(self, name: Name, scope: DefId, block: NodeId) -> (Ident, DefId) {
2584 self.adjust_ident(name.to_ident(), scope, block)
2587 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
2588 let expansion = match scope.krate {
2589 LOCAL_CRATE => self.hir.definitions().expansion(scope.index),
2592 let scope = match ident.span.adjust(expansion) {
2593 Some(macro_def) => self.hir.definitions().macro_def_scope(macro_def),
2594 None if block == DUMMY_NODE_ID => DefId::local(CRATE_DEF_INDEX), // Dummy DefId
2595 None => self.hir.get_module_parent(block),
2601 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2602 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2603 F: FnOnce(&[hir::Freevar]) -> T,
2605 let def_id = self.hir.local_def_id(fid);
2606 match self.freevars(def_id) {
2613 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
2616 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2617 let parent_id = tcx.hir.get_parent(id);
2618 let parent_def_id = tcx.hir.local_def_id(parent_id);
2619 let parent_item = tcx.hir.expect_item(parent_id);
2620 match parent_item.node {
2621 hir::ItemImpl(.., ref impl_item_refs) => {
2622 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2623 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2625 debug_assert_eq!(assoc_item.def_id, def_id);
2630 hir::ItemTrait(.., ref trait_item_refs) => {
2631 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2632 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2635 debug_assert_eq!(assoc_item.def_id, def_id);
2643 span_bug!(parent_item.span,
2644 "unexpected parent of trait or impl item or item not found: {:?}",
2648 /// Calculates the Sized-constraint.
2650 /// In fact, there are only a few options for the types in the constraint:
2651 /// - an obviously-unsized type
2652 /// - a type parameter or projection whose Sizedness can't be known
2653 /// - a tuple of type parameters or projections, if there are multiple
2655 /// - a TyError, if a type contained itself. The representability
2656 /// check should catch this case.
2657 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2659 -> &'tcx [Ty<'tcx>] {
2660 let def = tcx.adt_def(def_id);
2662 let result = tcx.intern_type_list(&def.variants.iter().flat_map(|v| {
2665 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2666 }).collect::<Vec<_>>());
2668 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2673 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2675 -> Lrc<Vec<DefId>> {
2676 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2677 let item = tcx.hir.expect_item(id);
2678 let vec: Vec<_> = match item.node {
2679 hir::ItemTrait(.., ref trait_item_refs) => {
2680 trait_item_refs.iter()
2681 .map(|trait_item_ref| trait_item_ref.id)
2682 .map(|id| tcx.hir.local_def_id(id.node_id))
2685 hir::ItemImpl(.., ref impl_item_refs) => {
2686 impl_item_refs.iter()
2687 .map(|impl_item_ref| impl_item_ref.id)
2688 .map(|id| tcx.hir.local_def_id(id.node_id))
2691 hir::ItemTraitAlias(..) => vec![],
2692 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2697 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
2698 tcx.hir.span_if_local(def_id).unwrap()
2701 /// If the given def ID describes an item belonging to a trait,
2702 /// return the ID of the trait that the trait item belongs to.
2703 /// Otherwise, return `None`.
2704 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
2705 tcx.opt_associated_item(def_id)
2706 .and_then(|associated_item| {
2707 match associated_item.container {
2708 TraitContainer(def_id) => Some(def_id),
2709 ImplContainer(_) => None
2714 /// See `ParamEnv` struct def'n for details.
2715 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2718 // Compute the bounds on Self and the type parameters.
2720 let bounds = tcx.predicates_of(def_id).instantiate_identity(tcx);
2721 let predicates = bounds.predicates;
2723 // Finally, we have to normalize the bounds in the environment, in
2724 // case they contain any associated type projections. This process
2725 // can yield errors if the put in illegal associated types, like
2726 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2727 // report these errors right here; this doesn't actually feel
2728 // right to me, because constructing the environment feels like a
2729 // kind of a "idempotent" action, but I'm not sure where would be
2730 // a better place. In practice, we construct environments for
2731 // every fn once during type checking, and we'll abort if there
2732 // are any errors at that point, so after type checking you can be
2733 // sure that this will succeed without errors anyway.
2735 let unnormalized_env = ty::ParamEnv::new(tcx.intern_predicates(&predicates),
2736 traits::Reveal::UserFacing);
2738 let body_id = tcx.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
2739 tcx.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_id)
2741 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
2742 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
2745 fn crate_disambiguator<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2746 crate_num: CrateNum) -> CrateDisambiguator {
2747 assert_eq!(crate_num, LOCAL_CRATE);
2748 tcx.sess.local_crate_disambiguator()
2751 fn original_crate_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2752 crate_num: CrateNum) -> Symbol {
2753 assert_eq!(crate_num, LOCAL_CRATE);
2754 tcx.crate_name.clone()
2757 fn crate_hash<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2758 crate_num: CrateNum)
2760 assert_eq!(crate_num, LOCAL_CRATE);
2764 fn instance_def_size_estimate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2765 instance_def: InstanceDef<'tcx>)
2767 match instance_def {
2768 InstanceDef::Item(..) |
2769 InstanceDef::DropGlue(..) => {
2770 let mir = tcx.instance_mir(instance_def);
2771 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
2773 // Estimate the size of other compiler-generated shims to be 1.
2778 pub fn provide(providers: &mut ty::maps::Providers) {
2779 context::provide(providers);
2780 erase_regions::provide(providers);
2781 layout::provide(providers);
2782 util::provide(providers);
2783 *providers = ty::maps::Providers {
2785 associated_item_def_ids,
2786 adt_sized_constraint,
2790 crate_disambiguator,
2791 original_crate_name,
2793 trait_impls_of: trait_def::trait_impls_of_provider,
2794 instance_def_size_estimate,
2799 /// A map for the local crate mapping each type to a vector of its
2800 /// inherent impls. This is not meant to be used outside of coherence;
2801 /// rather, you should request the vector for a specific type via
2802 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2803 /// (constructing this map requires touching the entire crate).
2804 #[derive(Clone, Debug)]
2805 pub struct CrateInherentImpls {
2806 pub inherent_impls: DefIdMap<Lrc<Vec<DefId>>>,
2809 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
2810 pub struct SymbolName {
2811 // FIXME: we don't rely on interning or equality here - better have
2812 // this be a `&'tcx str`.
2813 pub name: InternedString
2816 impl_stable_hash_for!(struct self::SymbolName {
2821 pub fn new(name: &str) -> SymbolName {
2823 name: Symbol::intern(name).as_str()
2828 impl Deref for SymbolName {
2831 fn deref(&self) -> &str { &self.name }
2834 impl fmt::Display for SymbolName {
2835 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2836 fmt::Display::fmt(&self.name, fmt)
2840 impl fmt::Debug for SymbolName {
2841 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2842 fmt::Display::fmt(&self.name, fmt)