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::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
26 use middle::privacy::AccessLevels;
27 use middle::resolve_lifetime::ObjectLifetimeDefault;
29 use mir::interpret::GlobalId;
30 use mir::GeneratorLayout;
31 use session::CrateDisambiguator;
32 use traits::{self, Reveal};
34 use ty::subst::{Subst, Substs};
35 use ty::util::{IntTypeExt, Discr};
36 use ty::walk::TypeWalker;
37 use util::captures::Captures;
38 use util::nodemap::{NodeSet, DefIdMap, FxHashMap};
40 use serialize::{self, Encodable, Encoder};
41 use std::cell::RefCell;
44 use std::hash::{Hash, Hasher};
46 use rustc_data_structures::sync::Lrc;
48 use std::vec::IntoIter;
50 use syntax::ast::{self, DUMMY_NODE_ID, Name, Ident, NodeId};
52 use syntax::ext::hygiene::Mark;
53 use syntax::symbol::{Symbol, LocalInternedString, InternedString};
54 use syntax_pos::{DUMMY_SP, Span};
56 use rustc_data_structures::accumulate_vec::IntoIter as AccIntoIter;
57 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
62 pub use self::sty::{Binder, CanonicalVar, DebruijnIndex};
63 pub use self::sty::{FnSig, GenSig, PolyFnSig, PolyGenSig};
64 pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
65 pub use self::sty::{ClosureSubsts, GeneratorSubsts, UpvarSubsts, TypeAndMut};
66 pub use self::sty::{TraitRef, TypeVariants, PolyTraitRef};
67 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
68 pub use self::sty::{ExistentialProjection, PolyExistentialProjection, Const};
69 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
70 pub use self::sty::RegionKind;
71 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid};
72 pub use self::sty::BoundRegion::*;
73 pub use self::sty::InferTy::*;
74 pub use self::sty::RegionKind::*;
75 pub use self::sty::TypeVariants::*;
77 pub use self::binding::BindingMode;
78 pub use self::binding::BindingMode::*;
80 pub use self::context::{TyCtxt, GlobalArenas, AllArenas, tls, keep_local};
81 pub use self::context::{Lift, TypeckTables, InterpretInterner};
83 pub use self::instance::{Instance, InstanceDef};
85 pub use self::trait_def::TraitDef;
87 pub use self::maps::queries;
98 pub mod inhabitedness;
115 mod structural_impls;
120 /// The complete set of all analyses described in this module. This is
121 /// produced by the driver and fed to trans and later passes.
123 /// NB: These contents are being migrated into queries using the
124 /// *on-demand* infrastructure.
126 pub struct CrateAnalysis {
127 pub access_levels: Lrc<AccessLevels>,
129 pub glob_map: Option<hir::GlobMap>,
133 pub struct Resolutions {
134 pub freevars: FreevarMap,
135 pub trait_map: TraitMap,
136 pub maybe_unused_trait_imports: NodeSet,
137 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
138 pub export_map: ExportMap,
141 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
142 pub enum AssociatedItemContainer {
143 TraitContainer(DefId),
144 ImplContainer(DefId),
147 impl AssociatedItemContainer {
148 /// Asserts that this is the def-id of an associated item declared
149 /// in a trait, and returns the trait def-id.
150 pub fn assert_trait(&self) -> DefId {
152 TraitContainer(id) => id,
153 _ => bug!("associated item has wrong container type: {:?}", self)
157 pub fn id(&self) -> DefId {
159 TraitContainer(id) => id,
160 ImplContainer(id) => id,
165 /// The "header" of an impl is everything outside the body: a Self type, a trait
166 /// ref (in the case of a trait impl), and a set of predicates (from the
167 /// bounds/where clauses).
168 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
169 pub struct ImplHeader<'tcx> {
170 pub impl_def_id: DefId,
171 pub self_ty: Ty<'tcx>,
172 pub trait_ref: Option<TraitRef<'tcx>>,
173 pub predicates: Vec<Predicate<'tcx>>,
176 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
177 pub struct AssociatedItem {
180 pub kind: AssociatedKind,
182 pub defaultness: hir::Defaultness,
183 pub container: AssociatedItemContainer,
185 /// Whether this is a method with an explicit self
186 /// as its first argument, allowing method calls.
187 pub method_has_self_argument: bool,
190 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash, RustcEncodable, RustcDecodable)]
191 pub enum AssociatedKind {
197 impl AssociatedItem {
198 pub fn def(&self) -> Def {
200 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
201 AssociatedKind::Method => Def::Method(self.def_id),
202 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
206 /// Tests whether the associated item admits a non-trivial implementation
208 pub fn relevant_for_never<'tcx>(&self) -> bool {
210 AssociatedKind::Const => true,
211 AssociatedKind::Type => true,
212 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
213 AssociatedKind::Method => !self.method_has_self_argument,
217 pub fn signature<'a, 'tcx>(&self, tcx: &TyCtxt<'a, 'tcx, 'tcx>) -> String {
219 ty::AssociatedKind::Method => {
220 // We skip the binder here because the binder would deanonymize all
221 // late-bound regions, and we don't want method signatures to show up
222 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
223 // regions just fine, showing `fn(&MyType)`.
224 format!("{}", tcx.fn_sig(self.def_id).skip_binder())
226 ty::AssociatedKind::Type => format!("type {};", self.name.to_string()),
227 ty::AssociatedKind::Const => {
228 format!("const {}: {:?};", self.name.to_string(), tcx.type_of(self.def_id))
234 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
235 pub enum Visibility {
236 /// Visible everywhere (including in other crates).
238 /// Visible only in the given crate-local module.
240 /// Not visible anywhere in the local crate. This is the visibility of private external items.
244 pub trait DefIdTree: Copy {
245 fn parent(self, id: DefId) -> Option<DefId>;
247 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
248 if descendant.krate != ancestor.krate {
252 while descendant != ancestor {
253 match self.parent(descendant) {
254 Some(parent) => descendant = parent,
255 None => return false,
262 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
263 fn parent(self, id: DefId) -> Option<DefId> {
264 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
269 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt) -> Self {
271 hir::Public => Visibility::Public,
272 hir::Visibility::Crate => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
273 hir::Visibility::Restricted { ref path, .. } => match path.def {
274 // If there is no resolution, `resolve` will have already reported an error, so
275 // assume that the visibility is public to avoid reporting more privacy errors.
276 Def::Err => Visibility::Public,
277 def => Visibility::Restricted(def.def_id()),
280 Visibility::Restricted(tcx.hir.get_module_parent(id))
285 /// Returns true if an item with this visibility is accessible from the given block.
286 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
287 let restriction = match self {
288 // Public items are visible everywhere.
289 Visibility::Public => return true,
290 // Private items from other crates are visible nowhere.
291 Visibility::Invisible => return false,
292 // Restricted items are visible in an arbitrary local module.
293 Visibility::Restricted(other) if other.krate != module.krate => return false,
294 Visibility::Restricted(module) => module,
297 tree.is_descendant_of(module, restriction)
300 /// Returns true if this visibility is at least as accessible as the given visibility
301 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
302 let vis_restriction = match vis {
303 Visibility::Public => return self == Visibility::Public,
304 Visibility::Invisible => return true,
305 Visibility::Restricted(module) => module,
308 self.is_accessible_from(vis_restriction, tree)
311 // Returns true if this item is visible anywhere in the local crate.
312 pub fn is_visible_locally(self) -> bool {
314 Visibility::Public => true,
315 Visibility::Restricted(def_id) => def_id.is_local(),
316 Visibility::Invisible => false,
321 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
323 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
324 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
325 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
326 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
329 /// The crate variances map is computed during typeck and contains the
330 /// variance of every item in the local crate. You should not use it
331 /// directly, because to do so will make your pass dependent on the
332 /// HIR of every item in the local crate. Instead, use
333 /// `tcx.variances_of()` to get the variance for a *particular*
335 pub struct CrateVariancesMap {
336 /// For each item with generics, maps to a vector of the variance
337 /// of its generics. If an item has no generics, it will have no
339 pub variances: FxHashMap<DefId, Lrc<Vec<ty::Variance>>>,
341 /// An empty vector, useful for cloning.
342 pub empty_variance: Lrc<Vec<ty::Variance>>,
346 /// `a.xform(b)` combines the variance of a context with the
347 /// variance of a type with the following meaning. If we are in a
348 /// context with variance `a`, and we encounter a type argument in
349 /// a position with variance `b`, then `a.xform(b)` is the new
350 /// variance with which the argument appears.
356 /// Here, the "ambient" variance starts as covariant. `*mut T` is
357 /// invariant with respect to `T`, so the variance in which the
358 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
359 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
360 /// respect to its type argument `T`, and hence the variance of
361 /// the `i32` here is `Invariant.xform(Covariant)`, which results
362 /// (again) in `Invariant`.
366 /// fn(*const Vec<i32>, *mut Vec<i32)
368 /// The ambient variance is covariant. A `fn` type is
369 /// contravariant with respect to its parameters, so the variance
370 /// within which both pointer types appear is
371 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
372 /// T` is covariant with respect to `T`, so the variance within
373 /// which the first `Vec<i32>` appears is
374 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
375 /// is true for its `i32` argument. In the `*mut T` case, the
376 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
377 /// and hence the outermost type is `Invariant` with respect to
378 /// `Vec<i32>` (and its `i32` argument).
380 /// Source: Figure 1 of "Taming the Wildcards:
381 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
382 pub fn xform(self, v: ty::Variance) -> ty::Variance {
384 // Figure 1, column 1.
385 (ty::Covariant, ty::Covariant) => ty::Covariant,
386 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
387 (ty::Covariant, ty::Invariant) => ty::Invariant,
388 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
390 // Figure 1, column 2.
391 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
392 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
393 (ty::Contravariant, ty::Invariant) => ty::Invariant,
394 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
396 // Figure 1, column 3.
397 (ty::Invariant, _) => ty::Invariant,
399 // Figure 1, column 4.
400 (ty::Bivariant, _) => ty::Bivariant,
405 // Contains information needed to resolve types and (in the future) look up
406 // the types of AST nodes.
407 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
408 pub struct CReaderCacheKey {
413 // Flags that we track on types. These flags are propagated upwards
414 // through the type during type construction, so that we can quickly
415 // check whether the type has various kinds of types in it without
416 // recursing over the type itself.
418 pub struct TypeFlags: u32 {
419 const HAS_PARAMS = 1 << 0;
420 const HAS_SELF = 1 << 1;
421 const HAS_TY_INFER = 1 << 2;
422 const HAS_RE_INFER = 1 << 3;
423 const HAS_RE_SKOL = 1 << 4;
425 /// Does this have any `ReEarlyBound` regions? Used to
426 /// determine whether substitition is required, since those
427 /// represent regions that are bound in a `ty::Generics` and
428 /// hence may be substituted.
429 const HAS_RE_EARLY_BOUND = 1 << 5;
431 /// Does this have any region that "appears free" in the type?
432 /// Basically anything but `ReLateBound` and `ReErased`.
433 const HAS_FREE_REGIONS = 1 << 6;
435 /// Is an error type reachable?
436 const HAS_TY_ERR = 1 << 7;
437 const HAS_PROJECTION = 1 << 8;
439 // FIXME: Rename this to the actual property since it's used for generators too
440 const HAS_TY_CLOSURE = 1 << 9;
442 // true if there are "names" of types and regions and so forth
443 // that are local to a particular fn
444 const HAS_LOCAL_NAMES = 1 << 10;
446 // Present if the type belongs in a local type context.
447 // Only set for TyInfer other than Fresh.
448 const KEEP_IN_LOCAL_TCX = 1 << 11;
450 // Is there a projection that does not involve a bound region?
451 // Currently we can't normalize projections w/ bound regions.
452 const HAS_NORMALIZABLE_PROJECTION = 1 << 12;
454 // Set if this includes a "canonical" type or region var --
455 // ought to be true only for the results of canonicalization.
456 const HAS_CANONICAL_VARS = 1 << 13;
458 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
459 TypeFlags::HAS_SELF.bits |
460 TypeFlags::HAS_RE_EARLY_BOUND.bits;
462 // Flags representing the nominal content of a type,
463 // computed by FlagsComputation. If you add a new nominal
464 // flag, it should be added here too.
465 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
466 TypeFlags::HAS_SELF.bits |
467 TypeFlags::HAS_TY_INFER.bits |
468 TypeFlags::HAS_RE_INFER.bits |
469 TypeFlags::HAS_RE_SKOL.bits |
470 TypeFlags::HAS_RE_EARLY_BOUND.bits |
471 TypeFlags::HAS_FREE_REGIONS.bits |
472 TypeFlags::HAS_TY_ERR.bits |
473 TypeFlags::HAS_PROJECTION.bits |
474 TypeFlags::HAS_TY_CLOSURE.bits |
475 TypeFlags::HAS_LOCAL_NAMES.bits |
476 TypeFlags::KEEP_IN_LOCAL_TCX.bits |
477 TypeFlags::HAS_CANONICAL_VARS.bits;
481 pub struct TyS<'tcx> {
482 pub sty: TypeVariants<'tcx>,
483 pub flags: TypeFlags,
485 // the maximal depth of any bound regions appearing in this type.
489 impl<'tcx> PartialEq for TyS<'tcx> {
491 fn eq(&self, other: &TyS<'tcx>) -> bool {
492 // (self as *const _) == (other as *const _)
493 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
496 impl<'tcx> Eq for TyS<'tcx> {}
498 impl<'tcx> Hash for TyS<'tcx> {
499 fn hash<H: Hasher>(&self, s: &mut H) {
500 (self as *const TyS).hash(s)
504 impl<'tcx> TyS<'tcx> {
505 pub fn is_primitive_ty(&self) -> bool {
507 TypeVariants::TyBool |
508 TypeVariants::TyChar |
509 TypeVariants::TyInt(_) |
510 TypeVariants::TyUint(_) |
511 TypeVariants::TyFloat(_) |
512 TypeVariants::TyInfer(InferTy::IntVar(_)) |
513 TypeVariants::TyInfer(InferTy::FloatVar(_)) |
514 TypeVariants::TyInfer(InferTy::FreshIntTy(_)) |
515 TypeVariants::TyInfer(InferTy::FreshFloatTy(_)) => true,
516 TypeVariants::TyRef(_, x, _) => x.is_primitive_ty(),
521 pub fn is_suggestable(&self) -> bool {
523 TypeVariants::TyAnon(..) |
524 TypeVariants::TyFnDef(..) |
525 TypeVariants::TyFnPtr(..) |
526 TypeVariants::TyDynamic(..) |
527 TypeVariants::TyClosure(..) |
528 TypeVariants::TyInfer(..) |
529 TypeVariants::TyProjection(..) => false,
535 impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for ty::TyS<'gcx> {
536 fn hash_stable<W: StableHasherResult>(&self,
537 hcx: &mut StableHashingContext<'a>,
538 hasher: &mut StableHasher<W>) {
542 // The other fields just provide fast access to information that is
543 // also contained in `sty`, so no need to hash them.
548 sty.hash_stable(hcx, hasher);
552 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
554 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
555 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
557 pub type CanonicalTy<'gcx> = Canonical<'gcx, Ty<'gcx>>;
559 impl <'gcx: 'tcx, 'tcx> Canonicalize<'gcx, 'tcx> for Ty<'tcx> {
560 type Canonicalized = CanonicalTy<'gcx>;
562 fn intern(_gcx: TyCtxt<'_, 'gcx, 'gcx>,
563 value: Canonical<'gcx, Self::Lifted>) -> Self::Canonicalized {
568 /// A wrapper for slices with the additional invariant
569 /// that the slice is interned and no other slice with
570 /// the same contents can exist in the same context.
571 /// This means we can use pointer + length for both
572 /// equality comparisons and hashing.
573 #[derive(Debug, RustcEncodable)]
574 pub struct Slice<T>([T]);
576 impl<T> PartialEq for Slice<T> {
578 fn eq(&self, other: &Slice<T>) -> bool {
579 (&self.0 as *const [T]) == (&other.0 as *const [T])
582 impl<T> Eq for Slice<T> {}
584 impl<T> Hash for Slice<T> {
585 fn hash<H: Hasher>(&self, s: &mut H) {
586 (self.as_ptr(), self.len()).hash(s)
590 impl<T> Deref for Slice<T> {
592 fn deref(&self) -> &[T] {
597 impl<'a, T> IntoIterator for &'a Slice<T> {
599 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
600 fn into_iter(self) -> Self::IntoIter {
605 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {}
608 pub fn empty<'a>() -> &'a Slice<T> {
610 mem::transmute(slice::from_raw_parts(0x1 as *const T, 0))
615 /// Upvars do not get their own node-id. Instead, we use the pair of
616 /// the original var id (that is, the root variable that is referenced
617 /// by the upvar) and the id of the closure expression.
618 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
620 pub var_id: hir::HirId,
621 pub closure_expr_id: LocalDefId,
624 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
625 pub enum BorrowKind {
626 /// Data must be immutable and is aliasable.
629 /// Data must be immutable but not aliasable. This kind of borrow
630 /// cannot currently be expressed by the user and is used only in
631 /// implicit closure bindings. It is needed when the closure
632 /// is borrowing or mutating a mutable referent, e.g.:
634 /// let x: &mut isize = ...;
635 /// let y = || *x += 5;
637 /// If we were to try to translate this closure into a more explicit
638 /// form, we'd encounter an error with the code as written:
640 /// struct Env { x: & &mut isize }
641 /// let x: &mut isize = ...;
642 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
643 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
645 /// This is then illegal because you cannot mutate a `&mut` found
646 /// in an aliasable location. To solve, you'd have to translate with
647 /// an `&mut` borrow:
649 /// struct Env { x: & &mut isize }
650 /// let x: &mut isize = ...;
651 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
652 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
654 /// Now the assignment to `**env.x` is legal, but creating a
655 /// mutable pointer to `x` is not because `x` is not mutable. We
656 /// could fix this by declaring `x` as `let mut x`. This is ok in
657 /// user code, if awkward, but extra weird for closures, since the
658 /// borrow is hidden.
660 /// So we introduce a "unique imm" borrow -- the referent is
661 /// immutable, but not aliasable. This solves the problem. For
662 /// simplicity, we don't give users the way to express this
663 /// borrow, it's just used when translating closures.
666 /// Data is mutable and not aliasable.
670 /// Information describing the capture of an upvar. This is computed
671 /// during `typeck`, specifically by `regionck`.
672 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
673 pub enum UpvarCapture<'tcx> {
674 /// Upvar is captured by value. This is always true when the
675 /// closure is labeled `move`, but can also be true in other cases
676 /// depending on inference.
679 /// Upvar is captured by reference.
680 ByRef(UpvarBorrow<'tcx>),
683 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
684 pub struct UpvarBorrow<'tcx> {
685 /// The kind of borrow: by-ref upvars have access to shared
686 /// immutable borrows, which are not part of the normal language
688 pub kind: BorrowKind,
690 /// Region of the resulting reference.
691 pub region: ty::Region<'tcx>,
694 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
696 #[derive(Copy, Clone)]
697 pub struct ClosureUpvar<'tcx> {
703 #[derive(Clone, Copy, PartialEq, Eq)]
704 pub enum IntVarValue {
706 UintType(ast::UintTy),
709 #[derive(Clone, Copy, PartialEq, Eq)]
710 pub struct FloatVarValue(pub ast::FloatTy);
712 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable)]
713 pub struct TypeParamDef {
714 pub has_default: bool,
715 pub object_lifetime_default: ObjectLifetimeDefault,
716 pub synthetic: Option<hir::SyntheticTyParamKind>,
719 impl ty::EarlyBoundRegion {
720 pub fn to_bound_region(&self) -> ty::BoundRegion {
721 ty::BoundRegion::BrNamed(self.def_id, self.name)
725 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
726 pub enum GenericParamDefKind {
731 #[derive(Clone, RustcEncodable, RustcDecodable)]
732 pub struct GenericParamDef {
733 pub name: InternedString,
737 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
738 /// on generic parameter `'a`/`T`, asserts data behind the parameter
739 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
740 pub pure_wrt_drop: bool,
742 pub kind: GenericParamDefKind,
745 impl GenericParamDef {
746 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
748 GenericParamDefKind::Lifetime => {
749 ty::EarlyBoundRegion {
755 _ => bug!("cannot convert a non-lifetime parameter def to an early bound region")
759 pub fn to_bound_region(&self) -> ty::BoundRegion {
761 GenericParamDefKind::Lifetime => {
762 self.to_early_bound_region_data().to_bound_region()
764 _ => bug!("cannot convert a non-lifetime parameter def to an early bound region")
769 pub struct GenericParamCount {
770 pub lifetimes: usize,
774 /// Information about the formal type/lifetime parameters associated
775 /// with an item or method. Analogous to hir::Generics.
777 /// The ordering of parameters is the same as in Subst (excluding child generics):
778 /// Self (optionally), Lifetime params..., Type params...
779 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
780 pub struct Generics {
781 pub parent: Option<DefId>,
782 pub parent_count: usize,
783 pub params: Vec<GenericParamDef>,
785 /// Reverse map to the `index` field of each `GenericParamDef`
786 pub param_def_id_to_index: FxHashMap<DefId, u32>,
789 pub has_late_bound_regions: Option<Span>,
792 impl<'a, 'gcx, 'tcx> Generics {
793 pub fn count(&self) -> usize {
794 self.parent_count + self.params.len()
797 pub fn own_counts(&self) -> GenericParamCount {
798 // We could cache this as a property of `GenericParamCount`, but
799 // the aim is to refactor this away entirely eventually and the
800 // presence of this method will be a constant reminder.
801 let mut own_counts = GenericParamCount {
806 for param in &self.params {
808 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
809 GenericParamDefKind::Type(_) => own_counts.types += 1,
816 pub fn requires_monomorphization(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
817 for param in &self.params {
819 GenericParamDefKind::Type(_) => return true,
820 GenericParamDefKind::Lifetime => {}
823 if let Some(parent_def_id) = self.parent {
824 let parent = tcx.generics_of(parent_def_id);
825 parent.requires_monomorphization(tcx)
831 pub fn region_param(&'tcx self,
832 param: &EarlyBoundRegion,
833 tcx: TyCtxt<'a, 'gcx, 'tcx>)
834 -> &'tcx GenericParamDef
836 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
837 let param = &self.params[index as usize];
839 ty::GenericParamDefKind::Lifetime => param,
840 _ => bug!("expected lifetime parameter, but found another generic parameter")
843 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
844 .region_param(param, tcx)
848 /// Returns the `TypeParamDef` associated with this `ParamTy`.
849 pub fn type_param(&'tcx self,
851 tcx: TyCtxt<'a, 'gcx, 'tcx>)
852 -> &'tcx GenericParamDef {
853 if let Some(index) = param.idx.checked_sub(self.parent_count as u32) {
854 let param = &self.params[index as usize];
856 ty::GenericParamDefKind::Type(_) => param,
857 _ => bug!("expected type parameter, but found another generic parameter")
860 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
861 .type_param(param, tcx)
866 /// Bounds on generics.
867 #[derive(Clone, Default)]
868 pub struct GenericPredicates<'tcx> {
869 pub parent: Option<DefId>,
870 pub predicates: Vec<Predicate<'tcx>>,
873 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
874 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
876 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
877 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
878 -> InstantiatedPredicates<'tcx> {
879 let mut instantiated = InstantiatedPredicates::empty();
880 self.instantiate_into(tcx, &mut instantiated, substs);
883 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
884 -> InstantiatedPredicates<'tcx> {
885 InstantiatedPredicates {
886 predicates: self.predicates.subst(tcx, substs)
890 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
891 instantiated: &mut InstantiatedPredicates<'tcx>,
892 substs: &Substs<'tcx>) {
893 if let Some(def_id) = self.parent {
894 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
896 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
899 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
900 -> InstantiatedPredicates<'tcx> {
901 let mut instantiated = InstantiatedPredicates::empty();
902 self.instantiate_identity_into(tcx, &mut instantiated);
906 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
907 instantiated: &mut InstantiatedPredicates<'tcx>) {
908 if let Some(def_id) = self.parent {
909 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
911 instantiated.predicates.extend(&self.predicates)
914 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
915 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
916 -> InstantiatedPredicates<'tcx>
918 assert_eq!(self.parent, None);
919 InstantiatedPredicates {
920 predicates: self.predicates.iter().map(|pred| {
921 pred.subst_supertrait(tcx, poly_trait_ref)
927 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
928 pub enum Predicate<'tcx> {
929 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
930 /// the `Self` type of the trait reference and `A`, `B`, and `C`
931 /// would be the type parameters.
932 Trait(PolyTraitPredicate<'tcx>),
935 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
938 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
940 /// where <T as TraitRef>::Name == X, approximately.
941 /// See `ProjectionPredicate` struct for details.
942 Projection(PolyProjectionPredicate<'tcx>),
945 WellFormed(Ty<'tcx>),
947 /// trait must be object-safe
950 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
951 /// for some substitutions `...` and T being a closure type.
952 /// Satisfied (or refuted) once we know the closure's kind.
953 ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
956 Subtype(PolySubtypePredicate<'tcx>),
958 /// Constant initializer must evaluate successfully.
959 ConstEvaluatable(DefId, &'tcx Substs<'tcx>),
962 /// The crate outlives map is computed during typeck and contains the
963 /// outlives of every item in the local crate. You should not use it
964 /// directly, because to do so will make your pass dependent on the
965 /// HIR of every item in the local crate. Instead, use
966 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
968 pub struct CratePredicatesMap<'tcx> {
969 /// For each struct with outlive bounds, maps to a vector of the
970 /// predicate of its outlive bounds. If an item has no outlives
971 /// bounds, it will have no entry.
972 pub predicates: FxHashMap<DefId, Lrc<Vec<ty::Predicate<'tcx>>>>,
974 /// An empty vector, useful for cloning.
975 pub empty_predicate: Lrc<Vec<ty::Predicate<'tcx>>>,
978 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
979 fn as_ref(&self) -> &Predicate<'tcx> {
984 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
985 /// Performs a substitution suitable for going from a
986 /// poly-trait-ref to supertraits that must hold if that
987 /// poly-trait-ref holds. This is slightly different from a normal
988 /// substitution in terms of what happens with bound regions. See
989 /// lengthy comment below for details.
990 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
991 trait_ref: &ty::PolyTraitRef<'tcx>)
992 -> ty::Predicate<'tcx>
994 // The interaction between HRTB and supertraits is not entirely
995 // obvious. Let me walk you (and myself) through an example.
997 // Let's start with an easy case. Consider two traits:
999 // trait Foo<'a> : Bar<'a,'a> { }
1000 // trait Bar<'b,'c> { }
1002 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
1003 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
1004 // knew that `Foo<'x>` (for any 'x) then we also know that
1005 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1006 // normal substitution.
1008 // In terms of why this is sound, the idea is that whenever there
1009 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1010 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1011 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1014 // Another example to be careful of is this:
1016 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
1017 // trait Bar1<'b,'c> { }
1019 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
1020 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
1021 // reason is similar to the previous example: any impl of
1022 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
1023 // basically we would want to collapse the bound lifetimes from
1024 // the input (`trait_ref`) and the supertraits.
1026 // To achieve this in practice is fairly straightforward. Let's
1027 // consider the more complicated scenario:
1029 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
1030 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
1031 // where both `'x` and `'b` would have a DB index of 1.
1032 // The substitution from the input trait-ref is therefore going to be
1033 // `'a => 'x` (where `'x` has a DB index of 1).
1034 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1035 // early-bound parameter and `'b' is a late-bound parameter with a
1037 // - If we replace `'a` with `'x` from the input, it too will have
1038 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1039 // just as we wanted.
1041 // There is only one catch. If we just apply the substitution `'a
1042 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1043 // adjust the DB index because we substituting into a binder (it
1044 // tries to be so smart...) resulting in `for<'x> for<'b>
1045 // Bar1<'x,'b>` (we have no syntax for this, so use your
1046 // imagination). Basically the 'x will have DB index of 2 and 'b
1047 // will have DB index of 1. Not quite what we want. So we apply
1048 // the substitution to the *contents* of the trait reference,
1049 // rather than the trait reference itself (put another way, the
1050 // substitution code expects equal binding levels in the values
1051 // from the substitution and the value being substituted into, and
1052 // this trick achieves that).
1054 let substs = &trait_ref.skip_binder().substs;
1056 Predicate::Trait(ref binder) =>
1057 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1058 Predicate::Subtype(ref binder) =>
1059 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1060 Predicate::RegionOutlives(ref binder) =>
1061 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1062 Predicate::TypeOutlives(ref binder) =>
1063 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1064 Predicate::Projection(ref binder) =>
1065 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1066 Predicate::WellFormed(data) =>
1067 Predicate::WellFormed(data.subst(tcx, substs)),
1068 Predicate::ObjectSafe(trait_def_id) =>
1069 Predicate::ObjectSafe(trait_def_id),
1070 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1071 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1072 Predicate::ConstEvaluatable(def_id, const_substs) =>
1073 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1078 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1079 pub struct TraitPredicate<'tcx> {
1080 pub trait_ref: TraitRef<'tcx>
1082 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1084 impl<'tcx> TraitPredicate<'tcx> {
1085 pub fn def_id(&self) -> DefId {
1086 self.trait_ref.def_id
1089 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
1090 self.trait_ref.input_types()
1093 pub fn self_ty(&self) -> Ty<'tcx> {
1094 self.trait_ref.self_ty()
1098 impl<'tcx> PolyTraitPredicate<'tcx> {
1099 pub fn def_id(&self) -> DefId {
1100 // ok to skip binder since trait def-id does not care about regions
1101 self.skip_binder().def_id()
1105 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1106 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
1107 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1108 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>,
1110 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>,
1112 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1113 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1115 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1116 pub struct SubtypePredicate<'tcx> {
1117 pub a_is_expected: bool,
1121 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1123 /// This kind of predicate has no *direct* correspondent in the
1124 /// syntax, but it roughly corresponds to the syntactic forms:
1126 /// 1. `T : TraitRef<..., Item=Type>`
1127 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1129 /// In particular, form #1 is "desugared" to the combination of a
1130 /// normal trait predicate (`T : TraitRef<...>`) and one of these
1131 /// predicates. Form #2 is a broader form in that it also permits
1132 /// equality between arbitrary types. Processing an instance of
1133 /// Form #2 eventually yields one of these `ProjectionPredicate`
1134 /// instances to normalize the LHS.
1135 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1136 pub struct ProjectionPredicate<'tcx> {
1137 pub projection_ty: ProjectionTy<'tcx>,
1141 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1143 impl<'tcx> PolyProjectionPredicate<'tcx> {
1144 /// Returns the def-id of the associated item being projected.
1145 pub fn item_def_id(&self) -> DefId {
1146 self.skip_binder().projection_ty.item_def_id
1149 pub fn to_poly_trait_ref(&self, tcx: TyCtxt) -> PolyTraitRef<'tcx> {
1150 // Note: unlike with TraitRef::to_poly_trait_ref(),
1151 // self.0.trait_ref is permitted to have escaping regions.
1152 // This is because here `self` has a `Binder` and so does our
1153 // return value, so we are preserving the number of binding
1155 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1158 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1159 self.map_bound(|predicate| predicate.ty)
1162 /// The DefId of the TraitItem for the associated type.
1164 /// Note that this is not the DefId of the TraitRef containing this
1165 /// associated type, which is in tcx.associated_item(projection_def_id()).container.
1166 pub fn projection_def_id(&self) -> DefId {
1167 // ok to skip binder since trait def-id does not care about regions
1168 self.skip_binder().projection_ty.item_def_id
1172 pub trait ToPolyTraitRef<'tcx> {
1173 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1176 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1177 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1178 ty::Binder::dummy(self.clone())
1182 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1183 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1184 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1188 pub trait ToPredicate<'tcx> {
1189 fn to_predicate(&self) -> Predicate<'tcx>;
1192 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1193 fn to_predicate(&self) -> Predicate<'tcx> {
1194 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1195 trait_ref: self.clone()
1200 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1201 fn to_predicate(&self) -> Predicate<'tcx> {
1202 ty::Predicate::Trait(self.to_poly_trait_predicate())
1206 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1207 fn to_predicate(&self) -> Predicate<'tcx> {
1208 Predicate::RegionOutlives(self.clone())
1212 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1213 fn to_predicate(&self) -> Predicate<'tcx> {
1214 Predicate::TypeOutlives(self.clone())
1218 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1219 fn to_predicate(&self) -> Predicate<'tcx> {
1220 Predicate::Projection(self.clone())
1224 impl<'tcx> Predicate<'tcx> {
1225 /// Iterates over the types in this predicate. Note that in all
1226 /// cases this is skipping over a binder, so late-bound regions
1227 /// with depth 0 are bound by the predicate.
1228 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1229 let vec: Vec<_> = match *self {
1230 ty::Predicate::Trait(ref data) => {
1231 data.skip_binder().input_types().collect()
1233 ty::Predicate::Subtype(binder) => {
1234 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1237 ty::Predicate::TypeOutlives(binder) => {
1238 vec![binder.skip_binder().0]
1240 ty::Predicate::RegionOutlives(..) => {
1243 ty::Predicate::Projection(ref data) => {
1244 let inner = data.skip_binder();
1245 inner.projection_ty.substs.types().chain(Some(inner.ty)).collect()
1247 ty::Predicate::WellFormed(data) => {
1250 ty::Predicate::ObjectSafe(_trait_def_id) => {
1253 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1254 closure_substs.substs.types().collect()
1256 ty::Predicate::ConstEvaluatable(_, substs) => {
1257 substs.types().collect()
1261 // The only reason to collect into a vector here is that I was
1262 // too lazy to make the full (somewhat complicated) iterator
1263 // type that would be needed here. But I wanted this fn to
1264 // return an iterator conceptually, rather than a `Vec`, so as
1265 // to be closer to `Ty::walk`.
1269 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1271 Predicate::Trait(ref t) => {
1272 Some(t.to_poly_trait_ref())
1274 Predicate::Projection(..) |
1275 Predicate::Subtype(..) |
1276 Predicate::RegionOutlives(..) |
1277 Predicate::WellFormed(..) |
1278 Predicate::ObjectSafe(..) |
1279 Predicate::ClosureKind(..) |
1280 Predicate::TypeOutlives(..) |
1281 Predicate::ConstEvaluatable(..) => {
1287 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1289 Predicate::TypeOutlives(data) => {
1292 Predicate::Trait(..) |
1293 Predicate::Projection(..) |
1294 Predicate::Subtype(..) |
1295 Predicate::RegionOutlives(..) |
1296 Predicate::WellFormed(..) |
1297 Predicate::ObjectSafe(..) |
1298 Predicate::ClosureKind(..) |
1299 Predicate::ConstEvaluatable(..) => {
1306 /// Represents the bounds declared on a particular set of type
1307 /// parameters. Should eventually be generalized into a flag list of
1308 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1309 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1310 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1311 /// the `GenericPredicates` are expressed in terms of the bound type
1312 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1313 /// represented a set of bounds for some particular instantiation,
1314 /// meaning that the generic parameters have been substituted with
1319 /// struct Foo<T,U:Bar<T>> { ... }
1321 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1322 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1323 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1324 /// [usize:Bar<isize>]]`.
1326 pub struct InstantiatedPredicates<'tcx> {
1327 pub predicates: Vec<Predicate<'tcx>>,
1330 impl<'tcx> InstantiatedPredicates<'tcx> {
1331 pub fn empty() -> InstantiatedPredicates<'tcx> {
1332 InstantiatedPredicates { predicates: vec![] }
1335 pub fn is_empty(&self) -> bool {
1336 self.predicates.is_empty()
1340 /// "Universes" are used during type- and trait-checking in the
1341 /// presence of `for<..>` binders to control what sets of names are
1342 /// visible. Universes are arranged into a tree: the root universe
1343 /// contains names that are always visible. But when you enter into
1344 /// some subuniverse, then it may add names that are only visible
1345 /// within that subtree (but it can still name the names of its
1346 /// ancestor universes).
1348 /// To make this more concrete, consider this program:
1352 /// fn bar<T>(x: T) {
1353 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1357 /// The struct name `Foo` is in the root universe U0. But the type
1358 /// parameter `T`, introduced on `bar`, is in a subuniverse U1 --
1359 /// i.e., within `bar`, we can name both `T` and `Foo`, but outside of
1360 /// `bar`, we cannot name `T`. Then, within the type of `y`, the
1361 /// region `'a` is in a subuniverse U2 of U1, because we can name it
1362 /// inside the fn type but not outside.
1364 /// Universes are related to **skolemization** -- which is a way of
1365 /// doing type- and trait-checking around these "forall" binders (also
1366 /// called **universal quantification**). The idea is that when, in
1367 /// the body of `bar`, we refer to `T` as a type, we aren't referring
1368 /// to any type in particular, but rather a kind of "fresh" type that
1369 /// is distinct from all other types we have actually declared. This
1370 /// is called a **skolemized** type, and we use universes to talk
1371 /// about this. In other words, a type name in universe 0 always
1372 /// corresponds to some "ground" type that the user declared, but a
1373 /// type name in a non-zero universe is a skolemized type -- an
1374 /// idealized representative of "types in general" that we use for
1375 /// checking generic functions.
1376 #[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
1377 pub struct UniverseIndex(u32);
1379 impl UniverseIndex {
1380 /// The root universe, where things that the user defined are
1382 pub const ROOT: Self = UniverseIndex(0);
1384 /// A "subuniverse" corresponds to being inside a `forall` quantifier.
1385 /// So, for example, suppose we have this type in universe `U`:
1388 /// for<'a> fn(&'a u32)
1391 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1392 /// subuniverse of `U` -- in this new universe, we can name the
1393 /// region `'a`, but that region was not nameable from `U` because
1394 /// it was not in scope there.
1395 pub fn subuniverse(self) -> UniverseIndex {
1396 UniverseIndex(self.0.checked_add(1).unwrap())
1399 pub fn as_u32(&self) -> u32 {
1403 pub fn as_usize(&self) -> usize {
1408 impl From<u32> for UniverseIndex {
1409 fn from(index: u32) -> Self {
1410 UniverseIndex(index)
1414 /// When type checking, we use the `ParamEnv` to track
1415 /// details about the set of where-clauses that are in scope at this
1416 /// particular point.
1417 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1418 pub struct ParamEnv<'tcx> {
1419 /// Obligations that the caller must satisfy. This is basically
1420 /// the set of bounds on the in-scope type parameters, translated
1421 /// into Obligations, and elaborated and normalized.
1422 pub caller_bounds: &'tcx Slice<ty::Predicate<'tcx>>,
1424 /// Typically, this is `Reveal::UserFacing`, but during trans we
1425 /// want `Reveal::All` -- note that this is always paired with an
1426 /// empty environment. To get that, use `ParamEnv::reveal()`.
1427 pub reveal: traits::Reveal,
1430 impl<'tcx> ParamEnv<'tcx> {
1431 /// Construct a trait environment suitable for contexts where
1432 /// there are no where clauses in scope. Hidden types (like `impl
1433 /// Trait`) are left hidden, so this is suitable for ordinary
1435 pub fn empty() -> Self {
1436 Self::new(ty::Slice::empty(), Reveal::UserFacing)
1439 /// Construct a trait environment with no where clauses in scope
1440 /// where the values of all `impl Trait` and other hidden types
1441 /// are revealed. This is suitable for monomorphized, post-typeck
1442 /// environments like trans or doing optimizations.
1444 /// NB. If you want to have predicates in scope, use `ParamEnv::new`,
1445 /// or invoke `param_env.with_reveal_all()`.
1446 pub fn reveal_all() -> Self {
1447 Self::new(ty::Slice::empty(), Reveal::All)
1450 /// Construct a trait environment with the given set of predicates.
1451 pub fn new(caller_bounds: &'tcx ty::Slice<ty::Predicate<'tcx>>,
1454 ty::ParamEnv { caller_bounds, reveal }
1457 /// Returns a new parameter environment with the same clauses, but
1458 /// which "reveals" the true results of projections in all cases
1459 /// (even for associated types that are specializable). This is
1460 /// the desired behavior during trans and certain other special
1461 /// contexts; normally though we want to use `Reveal::UserFacing`,
1462 /// which is the default.
1463 pub fn with_reveal_all(self) -> Self {
1464 ty::ParamEnv { reveal: Reveal::All, ..self }
1467 /// Returns this same environment but with no caller bounds.
1468 pub fn without_caller_bounds(self) -> Self {
1469 ty::ParamEnv { caller_bounds: ty::Slice::empty(), ..self }
1472 /// Creates a suitable environment in which to perform trait
1473 /// queries on the given value. When type-checking, this is simply
1474 /// the pair of the environment plus value. But when reveal is set to
1475 /// All, then if `value` does not reference any type parameters, we will
1476 /// pair it with the empty environment. This improves caching and is generally
1479 /// NB: We preserve the environment when type-checking because it
1480 /// is possible for the user to have wacky where-clauses like
1481 /// `where Box<u32>: Copy`, which are clearly never
1482 /// satisfiable. We generally want to behave as if they were true,
1483 /// although the surrounding function is never reachable.
1484 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1486 Reveal::UserFacing => {
1495 || value.needs_infer()
1496 || value.has_param_types()
1497 || value.has_self_ty()
1505 param_env: self.without_caller_bounds(),
1514 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1515 pub struct ParamEnvAnd<'tcx, T> {
1516 pub param_env: ParamEnv<'tcx>,
1520 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1521 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1522 (self.param_env, self.value)
1526 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'gcx, T>
1527 where T: HashStable<StableHashingContext<'a>>
1529 fn hash_stable<W: StableHasherResult>(&self,
1530 hcx: &mut StableHashingContext<'a>,
1531 hasher: &mut StableHasher<W>) {
1537 param_env.hash_stable(hcx, hasher);
1538 value.hash_stable(hcx, hasher);
1542 #[derive(Copy, Clone, Debug)]
1543 pub struct Destructor {
1544 /// The def-id of the destructor method
1549 pub struct AdtFlags: u32 {
1550 const NO_ADT_FLAGS = 0;
1551 const IS_ENUM = 1 << 0;
1552 const IS_PHANTOM_DATA = 1 << 1;
1553 const IS_FUNDAMENTAL = 1 << 2;
1554 const IS_UNION = 1 << 3;
1555 const IS_BOX = 1 << 4;
1556 /// Indicates whether this abstract data type will be expanded on in future (new
1557 /// fields/variants) and as such, whether downstream crates must match exhaustively on the
1558 /// fields/variants of this data type.
1560 /// See RFC 2008 (<https://github.com/rust-lang/rfcs/pull/2008>).
1561 const IS_NON_EXHAUSTIVE = 1 << 5;
1566 pub struct VariantDef {
1567 /// The variant's DefId. If this is a tuple-like struct,
1568 /// this is the DefId of the struct's ctor.
1570 pub name: Name, // struct's name if this is a struct
1571 pub discr: VariantDiscr,
1572 pub fields: Vec<FieldDef>,
1573 pub ctor_kind: CtorKind,
1576 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1577 pub enum VariantDiscr {
1578 /// Explicit value for this variant, i.e. `X = 123`.
1579 /// The `DefId` corresponds to the embedded constant.
1582 /// The previous variant's discriminant plus one.
1583 /// For efficiency reasons, the distance from the
1584 /// last `Explicit` discriminant is being stored,
1585 /// or `0` for the first variant, if it has none.
1590 pub struct FieldDef {
1593 pub vis: Visibility,
1596 /// The definition of an abstract data type - a struct or enum.
1598 /// These are all interned (by intern_adt_def) into the adt_defs
1602 pub variants: Vec<VariantDef>,
1604 pub repr: ReprOptions,
1607 impl PartialEq for AdtDef {
1608 // AdtDef are always interned and this is part of TyS equality
1610 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1613 impl Eq for AdtDef {}
1615 impl Hash for AdtDef {
1617 fn hash<H: Hasher>(&self, s: &mut H) {
1618 (self as *const AdtDef).hash(s)
1622 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1623 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1628 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1631 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1632 fn hash_stable<W: StableHasherResult>(&self,
1633 hcx: &mut StableHashingContext<'a>,
1634 hasher: &mut StableHasher<W>) {
1636 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> =
1637 RefCell::new(FxHashMap());
1640 let hash: Fingerprint = CACHE.with(|cache| {
1641 let addr = self as *const AdtDef as usize;
1642 *cache.borrow_mut().entry(addr).or_insert_with(|| {
1650 let mut hasher = StableHasher::new();
1651 did.hash_stable(hcx, &mut hasher);
1652 variants.hash_stable(hcx, &mut hasher);
1653 flags.hash_stable(hcx, &mut hasher);
1654 repr.hash_stable(hcx, &mut hasher);
1660 hash.hash_stable(hcx, hasher);
1664 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
1665 pub enum AdtKind { Struct, Union, Enum }
1668 #[derive(RustcEncodable, RustcDecodable, Default)]
1669 pub struct ReprFlags: u8 {
1670 const IS_C = 1 << 0;
1671 const IS_SIMD = 1 << 1;
1672 const IS_TRANSPARENT = 1 << 2;
1673 // Internal only for now. If true, don't reorder fields.
1674 const IS_LINEAR = 1 << 3;
1676 // Any of these flags being set prevent field reordering optimisation.
1677 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1678 ReprFlags::IS_SIMD.bits |
1679 ReprFlags::IS_LINEAR.bits;
1683 impl_stable_hash_for!(struct ReprFlags {
1689 /// Represents the repr options provided by the user,
1690 #[derive(Copy, Clone, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1691 pub struct ReprOptions {
1692 pub int: Option<attr::IntType>,
1695 pub flags: ReprFlags,
1698 impl_stable_hash_for!(struct ReprOptions {
1706 pub fn new(tcx: TyCtxt, did: DefId) -> ReprOptions {
1707 let mut flags = ReprFlags::empty();
1708 let mut size = None;
1709 let mut max_align = 0;
1710 let mut min_pack = 0;
1711 for attr in tcx.get_attrs(did).iter() {
1712 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1713 flags.insert(match r {
1714 attr::ReprC => ReprFlags::IS_C,
1715 attr::ReprPacked(pack) => {
1716 min_pack = if min_pack > 0 {
1717 cmp::min(pack, min_pack)
1723 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
1724 attr::ReprSimd => ReprFlags::IS_SIMD,
1725 attr::ReprInt(i) => {
1729 attr::ReprAlign(align) => {
1730 max_align = cmp::max(align, max_align);
1737 // This is here instead of layout because the choice must make it into metadata.
1738 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1739 flags.insert(ReprFlags::IS_LINEAR);
1741 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
1745 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1747 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1749 pub fn packed(&self) -> bool { self.pack > 0 }
1751 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
1753 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1755 pub fn discr_type(&self) -> attr::IntType {
1756 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
1759 /// Returns true if this `#[repr()]` should inhabit "smart enum
1760 /// layout" optimizations, such as representing `Foo<&T>` as a
1762 pub fn inhibit_enum_layout_opt(&self) -> bool {
1763 self.c() || self.int.is_some()
1766 /// Returns true if this `#[repr()]` should inhibit struct field reordering
1767 /// optimizations, such as with repr(C) or repr(packed(1)).
1768 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
1769 !(self.flags & ReprFlags::IS_UNOPTIMISABLE).is_empty() || (self.pack == 1)
1773 impl<'a, 'gcx, 'tcx> AdtDef {
1777 variants: Vec<VariantDef>,
1778 repr: ReprOptions) -> Self {
1779 let mut flags = AdtFlags::NO_ADT_FLAGS;
1780 let attrs = tcx.get_attrs(did);
1781 if attr::contains_name(&attrs, "fundamental") {
1782 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1784 if Some(did) == tcx.lang_items().phantom_data() {
1785 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1787 if Some(did) == tcx.lang_items().owned_box() {
1788 flags = flags | AdtFlags::IS_BOX;
1790 if tcx.has_attr(did, "non_exhaustive") {
1791 flags = flags | AdtFlags::IS_NON_EXHAUSTIVE;
1794 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
1795 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
1796 AdtKind::Struct => {}
1807 pub fn is_struct(&self) -> bool {
1808 !self.is_union() && !self.is_enum()
1812 pub fn is_union(&self) -> bool {
1813 self.flags.intersects(AdtFlags::IS_UNION)
1817 pub fn is_enum(&self) -> bool {
1818 self.flags.intersects(AdtFlags::IS_ENUM)
1822 pub fn is_non_exhaustive(&self) -> bool {
1823 self.flags.intersects(AdtFlags::IS_NON_EXHAUSTIVE)
1826 /// Returns the kind of the ADT - Struct or Enum.
1828 pub fn adt_kind(&self) -> AdtKind {
1831 } else if self.is_union() {
1838 pub fn descr(&self) -> &'static str {
1839 match self.adt_kind() {
1840 AdtKind::Struct => "struct",
1841 AdtKind::Union => "union",
1842 AdtKind::Enum => "enum",
1846 pub fn variant_descr(&self) -> &'static str {
1847 match self.adt_kind() {
1848 AdtKind::Struct => "struct",
1849 AdtKind::Union => "union",
1850 AdtKind::Enum => "variant",
1854 /// Returns whether this type is #[fundamental] for the purposes
1855 /// of coherence checking.
1857 pub fn is_fundamental(&self) -> bool {
1858 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
1861 /// Returns true if this is PhantomData<T>.
1863 pub fn is_phantom_data(&self) -> bool {
1864 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
1867 /// Returns true if this is Box<T>.
1869 pub fn is_box(&self) -> bool {
1870 self.flags.intersects(AdtFlags::IS_BOX)
1873 /// Returns whether this type has a destructor.
1874 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
1875 self.destructor(tcx).is_some()
1878 /// Asserts this is a struct or union and returns its unique variant.
1879 pub fn non_enum_variant(&self) -> &VariantDef {
1880 assert!(self.is_struct() || self.is_union());
1885 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
1886 tcx.predicates_of(self.did)
1889 /// Returns an iterator over all fields contained
1892 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
1893 self.variants.iter().flat_map(|v| v.fields.iter())
1896 pub fn is_payloadfree(&self) -> bool {
1897 !self.variants.is_empty() &&
1898 self.variants.iter().all(|v| v.fields.is_empty())
1901 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
1904 .find(|v| v.did == vid)
1905 .expect("variant_with_id: unknown variant")
1908 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1911 .position(|v| v.did == vid)
1912 .expect("variant_index_with_id: unknown variant")
1915 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
1917 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
1918 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
1919 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.non_enum_variant(),
1920 _ => bug!("unexpected def {:?} in variant_of_def", def)
1925 pub fn eval_explicit_discr(
1927 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1929 ) -> Option<Discr<'tcx>> {
1930 let param_env = ParamEnv::empty();
1931 let repr_type = self.repr.discr_type();
1932 let substs = Substs::identity_for_item(tcx.global_tcx(), expr_did);
1933 let instance = ty::Instance::new(expr_did, substs);
1934 let cid = GlobalId {
1938 match tcx.const_eval(param_env.and(cid)) {
1940 // FIXME: Find the right type and use it instead of `val.ty` here
1941 if let Some(b) = val.assert_bits(val.ty) {
1942 trace!("discriminants: {} ({:?})", b, repr_type);
1948 info!("invalid enum discriminant: {:#?}", val);
1949 ::middle::const_val::struct_error(
1951 tcx.def_span(expr_did),
1952 "constant evaluation of enum discriminant resulted in non-integer",
1958 err.report(tcx, tcx.def_span(expr_did), "enum discriminant");
1959 if !expr_did.is_local() {
1960 span_bug!(tcx.def_span(expr_did),
1961 "variant discriminant evaluation succeeded \
1962 in its crate but failed locally");
1970 pub fn discriminants(
1972 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1973 ) -> impl Iterator<Item=Discr<'tcx>> + Captures<'gcx> + 'a {
1974 let repr_type = self.repr.discr_type();
1975 let initial = repr_type.initial_discriminant(tcx.global_tcx());
1976 let mut prev_discr = None::<Discr<'tcx>>;
1977 self.variants.iter().map(move |v| {
1978 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
1979 if let VariantDiscr::Explicit(expr_did) = v.discr {
1980 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
1984 prev_discr = Some(discr);
1990 /// Compute the discriminant value used by a specific variant.
1991 /// Unlike `discriminants`, this is (amortized) constant-time,
1992 /// only doing at most one query for evaluating an explicit
1993 /// discriminant (the last one before the requested variant),
1994 /// assuming there are no constant-evaluation errors there.
1995 pub fn discriminant_for_variant(&self,
1996 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1997 variant_index: usize)
1999 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2000 let explicit_value = val
2001 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2002 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx.global_tcx()));
2003 explicit_value.checked_add(tcx, offset as u128).0
2006 /// Yields a DefId for the discriminant and an offset to add to it
2007 /// Alternatively, if there is no explicit discriminant, returns the
2008 /// inferred discriminant directly
2009 pub fn discriminant_def_for_variant(
2011 variant_index: usize,
2012 ) -> (Option<DefId>, usize) {
2013 let mut explicit_index = variant_index;
2016 match self.variants[explicit_index].discr {
2017 ty::VariantDiscr::Relative(0) => {
2021 ty::VariantDiscr::Relative(distance) => {
2022 explicit_index -= distance;
2024 ty::VariantDiscr::Explicit(did) => {
2025 expr_did = Some(did);
2030 (expr_did, variant_index - explicit_index)
2033 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
2034 tcx.adt_destructor(self.did)
2037 /// Returns a list of types such that `Self: Sized` if and only
2038 /// if that type is Sized, or `TyErr` if this type is recursive.
2040 /// Oddly enough, checking that the sized-constraint is Sized is
2041 /// actually more expressive than checking all members:
2042 /// the Sized trait is inductive, so an associated type that references
2043 /// Self would prevent its containing ADT from being Sized.
2045 /// Due to normalization being eager, this applies even if
2046 /// the associated type is behind a pointer, e.g. issue #31299.
2047 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
2048 match tcx.try_get_query::<queries::adt_sized_constraint>(DUMMY_SP, self.did) {
2051 debug!("adt_sized_constraint: {:?} is recursive", self);
2052 // This should be reported as an error by `check_representable`.
2054 // Consider the type as Sized in the meanwhile to avoid
2055 // further errors. Delay our `bug` diagnostic here to get
2056 // emitted later as well in case we accidentally otherwise don't
2059 tcx.intern_type_list(&[tcx.types.err])
2064 fn sized_constraint_for_ty(&self,
2065 tcx: TyCtxt<'a, 'tcx, 'tcx>,
2068 let result = match ty.sty {
2069 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
2070 TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
2071 TyArray(..) | TyClosure(..) | TyGenerator(..) | TyNever => {
2080 TyGeneratorWitness(..) => {
2081 // these are never sized - return the target type
2085 TyTuple(ref tys) => {
2088 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
2092 TyAdt(adt, substs) => {
2094 let adt_tys = adt.sized_constraint(tcx);
2095 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
2098 .map(|ty| ty.subst(tcx, substs))
2099 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2103 TyProjection(..) | TyAnon(..) => {
2104 // must calculate explicitly.
2105 // FIXME: consider special-casing always-Sized projections
2110 // perf hack: if there is a `T: Sized` bound, then
2111 // we know that `T` is Sized and do not need to check
2114 let sized_trait = match tcx.lang_items().sized_trait() {
2116 _ => return vec![ty]
2118 let sized_predicate = Binder::dummy(TraitRef {
2119 def_id: sized_trait,
2120 substs: tcx.mk_substs_trait(ty, &[])
2122 let predicates = tcx.predicates_of(self.did).predicates;
2123 if predicates.into_iter().any(|p| p == sized_predicate) {
2131 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2135 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2140 impl<'a, 'gcx, 'tcx> FieldDef {
2141 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
2142 tcx.type_of(self.did).subst(tcx, subst)
2146 /// Represents the various closure traits in the Rust language. This
2147 /// will determine the type of the environment (`self`, in the
2148 /// desuaring) argument that the closure expects.
2150 /// You can get the environment type of a closure using
2151 /// `tcx.closure_env_ty()`.
2152 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
2153 pub enum ClosureKind {
2154 // Warning: Ordering is significant here! The ordering is chosen
2155 // because the trait Fn is a subtrait of FnMut and so in turn, and
2156 // hence we order it so that Fn < FnMut < FnOnce.
2162 impl<'a, 'tcx> ClosureKind {
2163 // This is the initial value used when doing upvar inference.
2164 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2166 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
2168 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
2169 ClosureKind::FnMut => {
2170 tcx.require_lang_item(FnMutTraitLangItem)
2172 ClosureKind::FnOnce => {
2173 tcx.require_lang_item(FnOnceTraitLangItem)
2178 /// True if this a type that impls this closure kind
2179 /// must also implement `other`.
2180 pub fn extends(self, other: ty::ClosureKind) -> bool {
2181 match (self, other) {
2182 (ClosureKind::Fn, ClosureKind::Fn) => true,
2183 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2184 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2185 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2186 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2187 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2192 /// Returns the representative scalar type for this closure kind.
2193 /// See `TyS::to_opt_closure_kind` for more details.
2194 pub fn to_ty(self, tcx: TyCtxt<'_, '_, 'tcx>) -> Ty<'tcx> {
2196 ty::ClosureKind::Fn => tcx.types.i8,
2197 ty::ClosureKind::FnMut => tcx.types.i16,
2198 ty::ClosureKind::FnOnce => tcx.types.i32,
2203 impl<'tcx> TyS<'tcx> {
2204 /// Iterator that walks `self` and any types reachable from
2205 /// `self`, in depth-first order. Note that just walks the types
2206 /// that appear in `self`, it does not descend into the fields of
2207 /// structs or variants. For example:
2210 /// isize => { isize }
2211 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2212 /// [isize] => { [isize], isize }
2214 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2215 TypeWalker::new(self)
2218 /// Iterator that walks the immediate children of `self`. Hence
2219 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2220 /// (but not `i32`, like `walk`).
2221 pub fn walk_shallow(&'tcx self) -> AccIntoIter<walk::TypeWalkerArray<'tcx>> {
2222 walk::walk_shallow(self)
2225 /// Walks `ty` and any types appearing within `ty`, invoking the
2226 /// callback `f` on each type. If the callback returns false, then the
2227 /// children of the current type are ignored.
2229 /// Note: prefer `ty.walk()` where possible.
2230 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2231 where F : FnMut(Ty<'tcx>) -> bool
2233 let mut walker = self.walk();
2234 while let Some(ty) = walker.next() {
2236 walker.skip_current_subtree();
2243 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2245 hir::MutMutable => MutBorrow,
2246 hir::MutImmutable => ImmBorrow,
2250 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2251 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2252 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2254 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2256 MutBorrow => hir::MutMutable,
2257 ImmBorrow => hir::MutImmutable,
2259 // We have no type corresponding to a unique imm borrow, so
2260 // use `&mut`. It gives all the capabilities of an `&uniq`
2261 // and hence is a safe "over approximation".
2262 UniqueImmBorrow => hir::MutMutable,
2266 pub fn to_user_str(&self) -> &'static str {
2268 MutBorrow => "mutable",
2269 ImmBorrow => "immutable",
2270 UniqueImmBorrow => "uniquely immutable",
2275 #[derive(Debug, Clone)]
2276 pub enum Attributes<'gcx> {
2277 Owned(Lrc<[ast::Attribute]>),
2278 Borrowed(&'gcx [ast::Attribute])
2281 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2282 type Target = [ast::Attribute];
2284 fn deref(&self) -> &[ast::Attribute] {
2286 &Attributes::Owned(ref data) => &data,
2287 &Attributes::Borrowed(data) => data
2292 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2293 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2294 self.typeck_tables_of(self.hir.body_owner_def_id(body))
2297 /// Returns an iterator of the def-ids for all body-owners in this
2298 /// crate. If you would prefer to iterate over the bodies
2299 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
2302 ) -> impl Iterator<Item = DefId> + Captures<'tcx> + Captures<'gcx> + 'a {
2306 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
2309 pub fn expr_span(self, id: NodeId) -> Span {
2310 match self.hir.find(id) {
2311 Some(hir_map::NodeExpr(e)) => {
2315 bug!("Node id {} is not an expr: {:?}", id, f);
2318 bug!("Node id {} is not present in the node map", id);
2323 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2324 self.associated_items(id)
2325 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2329 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2330 self.associated_items(did).any(|item| {
2331 item.relevant_for_never()
2335 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2336 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2337 match self.hir.get(node_id) {
2338 hir_map::NodeTraitItem(_) | hir_map::NodeImplItem(_) => true,
2342 match self.describe_def(def_id).expect("no def for def-id") {
2343 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2348 if is_associated_item {
2349 Some(self.associated_item(def_id))
2355 fn associated_item_from_trait_item_ref(self,
2356 parent_def_id: DefId,
2357 parent_vis: &hir::Visibility,
2358 trait_item_ref: &hir::TraitItemRef)
2360 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2361 let (kind, has_self) = match trait_item_ref.kind {
2362 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2363 hir::AssociatedItemKind::Method { has_self } => {
2364 (ty::AssociatedKind::Method, has_self)
2366 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2370 name: trait_item_ref.name,
2372 // Visibility of trait items is inherited from their traits.
2373 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2374 defaultness: trait_item_ref.defaultness,
2376 container: TraitContainer(parent_def_id),
2377 method_has_self_argument: has_self
2381 fn associated_item_from_impl_item_ref(self,
2382 parent_def_id: DefId,
2383 impl_item_ref: &hir::ImplItemRef)
2385 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2386 let (kind, has_self) = match impl_item_ref.kind {
2387 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2388 hir::AssociatedItemKind::Method { has_self } => {
2389 (ty::AssociatedKind::Method, has_self)
2391 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2394 ty::AssociatedItem {
2395 name: impl_item_ref.name,
2397 // Visibility of trait impl items doesn't matter.
2398 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2399 defaultness: impl_item_ref.defaultness,
2401 container: ImplContainer(parent_def_id),
2402 method_has_self_argument: has_self
2406 pub fn field_index(self, node_id: NodeId, tables: &TypeckTables) -> usize {
2407 let hir_id = self.hir.node_to_hir_id(node_id);
2408 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2411 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2412 variant.fields.iter().position(|field| {
2413 self.adjust_ident(ident.modern(), variant.did, DUMMY_NODE_ID).0 == field.name.to_ident()
2417 pub fn associated_items(
2420 ) -> impl Iterator<Item = ty::AssociatedItem> + 'a {
2421 let def_ids = self.associated_item_def_ids(def_id);
2422 Box::new((0..def_ids.len()).map(move |i| self.associated_item(def_ids[i])))
2423 as Box<dyn Iterator<Item = ty::AssociatedItem> + 'a>
2426 /// Returns true if the impls are the same polarity and are implementing
2427 /// a trait which contains no items
2428 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2429 if !self.features().overlapping_marker_traits {
2432 let trait1_is_empty = self.impl_trait_ref(def_id1)
2433 .map_or(false, |trait_ref| {
2434 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2436 let trait2_is_empty = self.impl_trait_ref(def_id2)
2437 .map_or(false, |trait_ref| {
2438 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2440 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2445 // Returns `ty::VariantDef` if `def` refers to a struct,
2446 // or variant or their constructors, panics otherwise.
2447 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2449 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2450 let enum_did = self.parent_def_id(did).unwrap();
2451 self.adt_def(enum_did).variant_with_id(did)
2453 Def::Struct(did) | Def::Union(did) => {
2454 self.adt_def(did).non_enum_variant()
2456 Def::StructCtor(ctor_did, ..) => {
2457 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2458 self.adt_def(did).non_enum_variant()
2460 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2464 /// Given a `VariantDef`, returns the def-id of the `AdtDef` of which it is a part.
2465 pub fn adt_def_id_of_variant(self, variant_def: &'tcx VariantDef) -> DefId {
2466 let def_key = self.def_key(variant_def.did);
2467 match def_key.disambiguated_data.data {
2468 // for enum variants and tuple structs, the def-id of the ADT itself
2469 // is the *parent* of the variant
2470 DefPathData::EnumVariant(..) | DefPathData::StructCtor =>
2471 DefId { krate: variant_def.did.krate, index: def_key.parent.unwrap() },
2473 // otherwise, for structs and unions, they share a def-id
2474 _ => variant_def.did,
2478 pub fn item_name(self, id: DefId) -> InternedString {
2479 if id.index == CRATE_DEF_INDEX {
2480 self.original_crate_name(id.krate).as_interned_str()
2482 let def_key = self.def_key(id);
2483 // The name of a StructCtor is that of its struct parent.
2484 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2485 self.item_name(DefId {
2487 index: def_key.parent.unwrap()
2490 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2491 bug!("item_name: no name for {:?}", self.def_path(id));
2497 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2498 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2502 ty::InstanceDef::Item(did) => {
2503 self.optimized_mir(did)
2505 ty::InstanceDef::Intrinsic(..) |
2506 ty::InstanceDef::FnPtrShim(..) |
2507 ty::InstanceDef::Virtual(..) |
2508 ty::InstanceDef::ClosureOnceShim { .. } |
2509 ty::InstanceDef::DropGlue(..) |
2510 ty::InstanceDef::CloneShim(..) => {
2511 self.mir_shims(instance)
2516 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2517 /// Returns None if there is no MIR for the DefId
2518 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2519 if self.is_mir_available(did) {
2520 Some(self.optimized_mir(did))
2526 /// Get the attributes of a definition.
2527 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2528 if let Some(id) = self.hir.as_local_node_id(did) {
2529 Attributes::Borrowed(self.hir.attrs(id))
2531 Attributes::Owned(self.item_attrs(did))
2535 /// Determine whether an item is annotated with an attribute
2536 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2537 attr::contains_name(&self.get_attrs(did), attr)
2540 /// Returns true if this is an `auto trait`.
2541 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
2542 self.trait_def(trait_def_id).has_auto_impl
2545 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
2546 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
2549 /// Given the def_id of an impl, return the def_id of the trait it implements.
2550 /// If it implements no trait, return `None`.
2551 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2552 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2555 /// If the given def ID describes a method belonging to an impl, return the
2556 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2557 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2558 let item = if def_id.krate != LOCAL_CRATE {
2559 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2560 Some(self.associated_item(def_id))
2565 self.opt_associated_item(def_id)
2569 Some(trait_item) => {
2570 match trait_item.container {
2571 TraitContainer(_) => None,
2572 ImplContainer(def_id) => Some(def_id),
2579 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2580 /// with the name of the crate containing the impl.
2581 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2582 if impl_did.is_local() {
2583 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2584 Ok(self.hir.span(node_id))
2586 Err(self.crate_name(impl_did.krate))
2590 // Hygienically compare a use-site name (`use_name`) for a field or an associated item with its
2591 // supposed definition name (`def_name`). The method also needs `DefId` of the supposed
2592 // definition's parent/scope to perform comparison.
2593 pub fn hygienic_eq(self, use_name: Name, def_name: Name, def_parent_def_id: DefId) -> bool {
2594 self.adjust(use_name, def_parent_def_id, DUMMY_NODE_ID).0 == def_name.to_ident()
2597 pub fn adjust(self, name: Name, scope: DefId, block: NodeId) -> (Ident, DefId) {
2598 self.adjust_ident(name.to_ident(), scope, block)
2601 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
2602 let expansion = match scope.krate {
2603 LOCAL_CRATE => self.hir.definitions().expansion(scope.index),
2606 let scope = match ident.span.adjust(expansion) {
2607 Some(macro_def) => self.hir.definitions().macro_def_scope(macro_def),
2608 None if block == DUMMY_NODE_ID => DefId::local(CRATE_DEF_INDEX), // Dummy DefId
2609 None => self.hir.get_module_parent(block),
2615 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2616 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2617 F: FnOnce(&[hir::Freevar]) -> T,
2619 let def_id = self.hir.local_def_id(fid);
2620 match self.freevars(def_id) {
2627 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
2630 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2631 let parent_id = tcx.hir.get_parent(id);
2632 let parent_def_id = tcx.hir.local_def_id(parent_id);
2633 let parent_item = tcx.hir.expect_item(parent_id);
2634 match parent_item.node {
2635 hir::ItemImpl(.., ref impl_item_refs) => {
2636 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2637 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2639 debug_assert_eq!(assoc_item.def_id, def_id);
2644 hir::ItemTrait(.., ref trait_item_refs) => {
2645 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2646 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2649 debug_assert_eq!(assoc_item.def_id, def_id);
2657 span_bug!(parent_item.span,
2658 "unexpected parent of trait or impl item or item not found: {:?}",
2662 /// Calculates the Sized-constraint.
2664 /// In fact, there are only a few options for the types in the constraint:
2665 /// - an obviously-unsized type
2666 /// - a type parameter or projection whose Sizedness can't be known
2667 /// - a tuple of type parameters or projections, if there are multiple
2669 /// - a TyError, if a type contained itself. The representability
2670 /// check should catch this case.
2671 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2673 -> &'tcx [Ty<'tcx>] {
2674 let def = tcx.adt_def(def_id);
2676 let result = tcx.intern_type_list(&def.variants.iter().flat_map(|v| {
2679 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2680 }).collect::<Vec<_>>());
2682 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2687 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2689 -> Lrc<Vec<DefId>> {
2690 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2691 let item = tcx.hir.expect_item(id);
2692 let vec: Vec<_> = match item.node {
2693 hir::ItemTrait(.., ref trait_item_refs) => {
2694 trait_item_refs.iter()
2695 .map(|trait_item_ref| trait_item_ref.id)
2696 .map(|id| tcx.hir.local_def_id(id.node_id))
2699 hir::ItemImpl(.., ref impl_item_refs) => {
2700 impl_item_refs.iter()
2701 .map(|impl_item_ref| impl_item_ref.id)
2702 .map(|id| tcx.hir.local_def_id(id.node_id))
2705 hir::ItemTraitAlias(..) => vec![],
2706 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2711 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
2712 tcx.hir.span_if_local(def_id).unwrap()
2715 /// If the given def ID describes an item belonging to a trait,
2716 /// return the ID of the trait that the trait item belongs to.
2717 /// Otherwise, return `None`.
2718 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
2719 tcx.opt_associated_item(def_id)
2720 .and_then(|associated_item| {
2721 match associated_item.container {
2722 TraitContainer(def_id) => Some(def_id),
2723 ImplContainer(_) => None
2728 /// See `ParamEnv` struct def'n for details.
2729 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2732 // Compute the bounds on Self and the type parameters.
2734 let bounds = tcx.predicates_of(def_id).instantiate_identity(tcx);
2735 let predicates = bounds.predicates;
2737 // Finally, we have to normalize the bounds in the environment, in
2738 // case they contain any associated type projections. This process
2739 // can yield errors if the put in illegal associated types, like
2740 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2741 // report these errors right here; this doesn't actually feel
2742 // right to me, because constructing the environment feels like a
2743 // kind of a "idempotent" action, but I'm not sure where would be
2744 // a better place. In practice, we construct environments for
2745 // every fn once during type checking, and we'll abort if there
2746 // are any errors at that point, so after type checking you can be
2747 // sure that this will succeed without errors anyway.
2749 let unnormalized_env = ty::ParamEnv::new(tcx.intern_predicates(&predicates),
2750 traits::Reveal::UserFacing);
2752 let body_id = tcx.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
2753 tcx.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_id)
2755 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
2756 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
2759 fn crate_disambiguator<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2760 crate_num: CrateNum) -> CrateDisambiguator {
2761 assert_eq!(crate_num, LOCAL_CRATE);
2762 tcx.sess.local_crate_disambiguator()
2765 fn original_crate_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2766 crate_num: CrateNum) -> Symbol {
2767 assert_eq!(crate_num, LOCAL_CRATE);
2768 tcx.crate_name.clone()
2771 fn crate_hash<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2772 crate_num: CrateNum)
2774 assert_eq!(crate_num, LOCAL_CRATE);
2778 fn instance_def_size_estimate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2779 instance_def: InstanceDef<'tcx>)
2781 match instance_def {
2782 InstanceDef::Item(..) |
2783 InstanceDef::DropGlue(..) => {
2784 let mir = tcx.instance_mir(instance_def);
2785 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
2787 // Estimate the size of other compiler-generated shims to be 1.
2792 pub fn provide(providers: &mut ty::maps::Providers) {
2793 context::provide(providers);
2794 erase_regions::provide(providers);
2795 layout::provide(providers);
2796 util::provide(providers);
2797 *providers = ty::maps::Providers {
2799 associated_item_def_ids,
2800 adt_sized_constraint,
2804 crate_disambiguator,
2805 original_crate_name,
2807 trait_impls_of: trait_def::trait_impls_of_provider,
2808 instance_def_size_estimate,
2813 /// A map for the local crate mapping each type to a vector of its
2814 /// inherent impls. This is not meant to be used outside of coherence;
2815 /// rather, you should request the vector for a specific type via
2816 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2817 /// (constructing this map requires touching the entire crate).
2818 #[derive(Clone, Debug)]
2819 pub struct CrateInherentImpls {
2820 pub inherent_impls: DefIdMap<Lrc<Vec<DefId>>>,
2823 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
2824 pub struct SymbolName {
2825 // FIXME: we don't rely on interning or equality here - better have
2826 // this be a `&'tcx str`.
2827 pub name: InternedString
2830 impl_stable_hash_for!(struct self::SymbolName {
2835 pub fn new(name: &str) -> SymbolName {
2837 name: Symbol::intern(name).as_interned_str()
2841 pub fn as_str(&self) -> LocalInternedString {
2846 impl fmt::Display for SymbolName {
2847 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2848 fmt::Display::fmt(&self.name, fmt)
2852 impl fmt::Debug for SymbolName {
2853 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2854 fmt::Display::fmt(&self.name, fmt)