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_FREE_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 /// Does this have any `ReLateBound` regions? Used to check
459 /// if a global bound is safe to evaluate.
460 const HAS_RE_LATE_BOUND = 1 << 14;
462 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
463 TypeFlags::HAS_SELF.bits |
464 TypeFlags::HAS_RE_EARLY_BOUND.bits;
466 // Flags representing the nominal content of a type,
467 // computed by FlagsComputation. If you add a new nominal
468 // flag, it should be added here too.
469 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
470 TypeFlags::HAS_SELF.bits |
471 TypeFlags::HAS_TY_INFER.bits |
472 TypeFlags::HAS_RE_INFER.bits |
473 TypeFlags::HAS_RE_SKOL.bits |
474 TypeFlags::HAS_RE_EARLY_BOUND.bits |
475 TypeFlags::HAS_FREE_REGIONS.bits |
476 TypeFlags::HAS_TY_ERR.bits |
477 TypeFlags::HAS_PROJECTION.bits |
478 TypeFlags::HAS_TY_CLOSURE.bits |
479 TypeFlags::HAS_FREE_LOCAL_NAMES.bits |
480 TypeFlags::KEEP_IN_LOCAL_TCX.bits |
481 TypeFlags::HAS_CANONICAL_VARS.bits |
482 TypeFlags::HAS_RE_LATE_BOUND.bits;
486 pub struct TyS<'tcx> {
487 pub sty: TypeVariants<'tcx>,
488 pub flags: TypeFlags,
490 // the maximal depth of any bound regions appearing in this type.
494 impl<'tcx> PartialEq for TyS<'tcx> {
496 fn eq(&self, other: &TyS<'tcx>) -> bool {
497 // (self as *const _) == (other as *const _)
498 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
501 impl<'tcx> Eq for TyS<'tcx> {}
503 impl<'tcx> Hash for TyS<'tcx> {
504 fn hash<H: Hasher>(&self, s: &mut H) {
505 (self as *const TyS).hash(s)
509 impl<'tcx> TyS<'tcx> {
510 pub fn is_primitive_ty(&self) -> bool {
512 TypeVariants::TyBool |
513 TypeVariants::TyChar |
514 TypeVariants::TyInt(_) |
515 TypeVariants::TyUint(_) |
516 TypeVariants::TyFloat(_) |
517 TypeVariants::TyInfer(InferTy::IntVar(_)) |
518 TypeVariants::TyInfer(InferTy::FloatVar(_)) |
519 TypeVariants::TyInfer(InferTy::FreshIntTy(_)) |
520 TypeVariants::TyInfer(InferTy::FreshFloatTy(_)) => true,
521 TypeVariants::TyRef(_, x, _) => x.is_primitive_ty(),
526 pub fn is_suggestable(&self) -> bool {
528 TypeVariants::TyAnon(..) |
529 TypeVariants::TyFnDef(..) |
530 TypeVariants::TyFnPtr(..) |
531 TypeVariants::TyDynamic(..) |
532 TypeVariants::TyClosure(..) |
533 TypeVariants::TyInfer(..) |
534 TypeVariants::TyProjection(..) => false,
540 impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for ty::TyS<'gcx> {
541 fn hash_stable<W: StableHasherResult>(&self,
542 hcx: &mut StableHashingContext<'a>,
543 hasher: &mut StableHasher<W>) {
547 // The other fields just provide fast access to information that is
548 // also contained in `sty`, so no need to hash them.
553 sty.hash_stable(hcx, hasher);
557 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
559 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
560 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
562 pub type CanonicalTy<'gcx> = Canonical<'gcx, Ty<'gcx>>;
564 impl <'gcx: 'tcx, 'tcx> Canonicalize<'gcx, 'tcx> for Ty<'tcx> {
565 type Canonicalized = CanonicalTy<'gcx>;
567 fn intern(_gcx: TyCtxt<'_, 'gcx, 'gcx>,
568 value: Canonical<'gcx, Self::Lifted>) -> Self::Canonicalized {
573 /// A wrapper for slices with the additional invariant
574 /// that the slice is interned and no other slice with
575 /// the same contents can exist in the same context.
576 /// This means we can use pointer + length for both
577 /// equality comparisons and hashing.
578 #[derive(Debug, RustcEncodable)]
579 pub struct Slice<T>([T]);
581 impl<T> PartialEq for Slice<T> {
583 fn eq(&self, other: &Slice<T>) -> bool {
584 (&self.0 as *const [T]) == (&other.0 as *const [T])
587 impl<T> Eq for Slice<T> {}
589 impl<T> Hash for Slice<T> {
590 fn hash<H: Hasher>(&self, s: &mut H) {
591 (self.as_ptr(), self.len()).hash(s)
595 impl<T> Deref for Slice<T> {
597 fn deref(&self) -> &[T] {
602 impl<'a, T> IntoIterator for &'a Slice<T> {
604 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
605 fn into_iter(self) -> Self::IntoIter {
610 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {}
613 pub fn empty<'a>() -> &'a Slice<T> {
615 mem::transmute(slice::from_raw_parts(0x1 as *const T, 0))
620 /// Upvars do not get their own node-id. Instead, we use the pair of
621 /// the original var id (that is, the root variable that is referenced
622 /// by the upvar) and the id of the closure expression.
623 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
625 pub var_id: hir::HirId,
626 pub closure_expr_id: LocalDefId,
629 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
630 pub enum BorrowKind {
631 /// Data must be immutable and is aliasable.
634 /// Data must be immutable but not aliasable. This kind of borrow
635 /// cannot currently be expressed by the user and is used only in
636 /// implicit closure bindings. It is needed when the closure
637 /// is borrowing or mutating a mutable referent, e.g.:
639 /// let x: &mut isize = ...;
640 /// let y = || *x += 5;
642 /// If we were to try to translate this closure into a more explicit
643 /// form, we'd encounter an error with the code as written:
645 /// struct Env { x: & &mut isize }
646 /// let x: &mut isize = ...;
647 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
648 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
650 /// This is then illegal because you cannot mutate a `&mut` found
651 /// in an aliasable location. To solve, you'd have to translate with
652 /// an `&mut` borrow:
654 /// struct Env { x: & &mut isize }
655 /// let x: &mut isize = ...;
656 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
657 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
659 /// Now the assignment to `**env.x` is legal, but creating a
660 /// mutable pointer to `x` is not because `x` is not mutable. We
661 /// could fix this by declaring `x` as `let mut x`. This is ok in
662 /// user code, if awkward, but extra weird for closures, since the
663 /// borrow is hidden.
665 /// So we introduce a "unique imm" borrow -- the referent is
666 /// immutable, but not aliasable. This solves the problem. For
667 /// simplicity, we don't give users the way to express this
668 /// borrow, it's just used when translating closures.
671 /// Data is mutable and not aliasable.
675 /// Information describing the capture of an upvar. This is computed
676 /// during `typeck`, specifically by `regionck`.
677 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
678 pub enum UpvarCapture<'tcx> {
679 /// Upvar is captured by value. This is always true when the
680 /// closure is labeled `move`, but can also be true in other cases
681 /// depending on inference.
684 /// Upvar is captured by reference.
685 ByRef(UpvarBorrow<'tcx>),
688 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
689 pub struct UpvarBorrow<'tcx> {
690 /// The kind of borrow: by-ref upvars have access to shared
691 /// immutable borrows, which are not part of the normal language
693 pub kind: BorrowKind,
695 /// Region of the resulting reference.
696 pub region: ty::Region<'tcx>,
699 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
701 #[derive(Copy, Clone)]
702 pub struct ClosureUpvar<'tcx> {
708 #[derive(Clone, Copy, PartialEq, Eq)]
709 pub enum IntVarValue {
711 UintType(ast::UintTy),
714 #[derive(Clone, Copy, PartialEq, Eq)]
715 pub struct FloatVarValue(pub ast::FloatTy);
717 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable)]
718 pub struct TypeParamDef {
719 pub has_default: bool,
720 pub object_lifetime_default: ObjectLifetimeDefault,
721 pub synthetic: Option<hir::SyntheticTyParamKind>,
724 impl ty::EarlyBoundRegion {
725 pub fn to_bound_region(&self) -> ty::BoundRegion {
726 ty::BoundRegion::BrNamed(self.def_id, self.name)
730 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
731 pub enum GenericParamDefKind {
736 #[derive(Clone, RustcEncodable, RustcDecodable)]
737 pub struct GenericParamDef {
738 pub name: InternedString,
742 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
743 /// on generic parameter `'a`/`T`, asserts data behind the parameter
744 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
745 pub pure_wrt_drop: bool,
747 pub kind: GenericParamDefKind,
750 impl GenericParamDef {
751 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
753 GenericParamDefKind::Lifetime => {
754 ty::EarlyBoundRegion {
760 _ => bug!("cannot convert a non-lifetime parameter def to an early bound region")
764 pub fn to_bound_region(&self) -> ty::BoundRegion {
766 GenericParamDefKind::Lifetime => {
767 self.to_early_bound_region_data().to_bound_region()
769 _ => bug!("cannot convert a non-lifetime parameter def to an early bound region")
774 pub struct GenericParamCount {
775 pub lifetimes: usize,
779 /// Information about the formal type/lifetime parameters associated
780 /// with an item or method. Analogous to hir::Generics.
782 /// The ordering of parameters is the same as in Subst (excluding child generics):
783 /// Self (optionally), Lifetime params..., Type params...
784 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
785 pub struct Generics {
786 pub parent: Option<DefId>,
787 pub parent_count: usize,
788 pub params: Vec<GenericParamDef>,
790 /// Reverse map to the `index` field of each `GenericParamDef`
791 pub param_def_id_to_index: FxHashMap<DefId, u32>,
794 pub has_late_bound_regions: Option<Span>,
797 impl<'a, 'gcx, 'tcx> Generics {
798 pub fn count(&self) -> usize {
799 self.parent_count + self.params.len()
802 pub fn own_counts(&self) -> GenericParamCount {
803 // We could cache this as a property of `GenericParamCount`, but
804 // the aim is to refactor this away entirely eventually and the
805 // presence of this method will be a constant reminder.
806 let mut own_counts = GenericParamCount {
811 for param in &self.params {
813 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
814 GenericParamDefKind::Type(_) => own_counts.types += 1,
821 pub fn requires_monomorphization(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
822 for param in &self.params {
824 GenericParamDefKind::Type(_) => return true,
825 GenericParamDefKind::Lifetime => {}
828 if let Some(parent_def_id) = self.parent {
829 let parent = tcx.generics_of(parent_def_id);
830 parent.requires_monomorphization(tcx)
836 pub fn region_param(&'tcx self,
837 param: &EarlyBoundRegion,
838 tcx: TyCtxt<'a, 'gcx, 'tcx>)
839 -> &'tcx GenericParamDef
841 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
842 let param = &self.params[index as usize];
844 ty::GenericParamDefKind::Lifetime => param,
845 _ => bug!("expected lifetime parameter, but found another generic parameter")
848 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
849 .region_param(param, tcx)
853 /// Returns the `TypeParamDef` associated with this `ParamTy`.
854 pub fn type_param(&'tcx self,
856 tcx: TyCtxt<'a, 'gcx, 'tcx>)
857 -> &'tcx GenericParamDef {
858 if let Some(index) = param.idx.checked_sub(self.parent_count as u32) {
859 let param = &self.params[index as usize];
861 ty::GenericParamDefKind::Type(_) => param,
862 _ => bug!("expected type parameter, but found another generic parameter")
865 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
866 .type_param(param, tcx)
871 /// Bounds on generics.
872 #[derive(Clone, Default)]
873 pub struct GenericPredicates<'tcx> {
874 pub parent: Option<DefId>,
875 pub predicates: Vec<Predicate<'tcx>>,
878 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
879 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
881 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
882 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
883 -> InstantiatedPredicates<'tcx> {
884 let mut instantiated = InstantiatedPredicates::empty();
885 self.instantiate_into(tcx, &mut instantiated, substs);
888 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
889 -> InstantiatedPredicates<'tcx> {
890 InstantiatedPredicates {
891 predicates: self.predicates.subst(tcx, substs)
895 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
896 instantiated: &mut InstantiatedPredicates<'tcx>,
897 substs: &Substs<'tcx>) {
898 if let Some(def_id) = self.parent {
899 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
901 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
904 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
905 -> InstantiatedPredicates<'tcx> {
906 let mut instantiated = InstantiatedPredicates::empty();
907 self.instantiate_identity_into(tcx, &mut instantiated);
911 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
912 instantiated: &mut InstantiatedPredicates<'tcx>) {
913 if let Some(def_id) = self.parent {
914 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
916 instantiated.predicates.extend(&self.predicates)
919 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
920 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
921 -> InstantiatedPredicates<'tcx>
923 assert_eq!(self.parent, None);
924 InstantiatedPredicates {
925 predicates: self.predicates.iter().map(|pred| {
926 pred.subst_supertrait(tcx, poly_trait_ref)
932 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
933 pub enum Predicate<'tcx> {
934 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
935 /// the `Self` type of the trait reference and `A`, `B`, and `C`
936 /// would be the type parameters.
937 Trait(PolyTraitPredicate<'tcx>),
940 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
943 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
945 /// where <T as TraitRef>::Name == X, approximately.
946 /// See `ProjectionPredicate` struct for details.
947 Projection(PolyProjectionPredicate<'tcx>),
950 WellFormed(Ty<'tcx>),
952 /// trait must be object-safe
955 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
956 /// for some substitutions `...` and T being a closure type.
957 /// Satisfied (or refuted) once we know the closure's kind.
958 ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
961 Subtype(PolySubtypePredicate<'tcx>),
963 /// Constant initializer must evaluate successfully.
964 ConstEvaluatable(DefId, &'tcx Substs<'tcx>),
967 /// The crate outlives map is computed during typeck and contains the
968 /// outlives of every item in the local crate. You should not use it
969 /// directly, because to do so will make your pass dependent on the
970 /// HIR of every item in the local crate. Instead, use
971 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
973 pub struct CratePredicatesMap<'tcx> {
974 /// For each struct with outlive bounds, maps to a vector of the
975 /// predicate of its outlive bounds. If an item has no outlives
976 /// bounds, it will have no entry.
977 pub predicates: FxHashMap<DefId, Lrc<Vec<ty::Predicate<'tcx>>>>,
979 /// An empty vector, useful for cloning.
980 pub empty_predicate: Lrc<Vec<ty::Predicate<'tcx>>>,
983 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
984 fn as_ref(&self) -> &Predicate<'tcx> {
989 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
990 /// Performs a substitution suitable for going from a
991 /// poly-trait-ref to supertraits that must hold if that
992 /// poly-trait-ref holds. This is slightly different from a normal
993 /// substitution in terms of what happens with bound regions. See
994 /// lengthy comment below for details.
995 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
996 trait_ref: &ty::PolyTraitRef<'tcx>)
997 -> ty::Predicate<'tcx>
999 // The interaction between HRTB and supertraits is not entirely
1000 // obvious. Let me walk you (and myself) through an example.
1002 // Let's start with an easy case. Consider two traits:
1004 // trait Foo<'a> : Bar<'a,'a> { }
1005 // trait Bar<'b,'c> { }
1007 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
1008 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
1009 // knew that `Foo<'x>` (for any 'x) then we also know that
1010 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1011 // normal substitution.
1013 // In terms of why this is sound, the idea is that whenever there
1014 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1015 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1016 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1019 // Another example to be careful of is this:
1021 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
1022 // trait Bar1<'b,'c> { }
1024 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
1025 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
1026 // reason is similar to the previous example: any impl of
1027 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
1028 // basically we would want to collapse the bound lifetimes from
1029 // the input (`trait_ref`) and the supertraits.
1031 // To achieve this in practice is fairly straightforward. Let's
1032 // consider the more complicated scenario:
1034 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
1035 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
1036 // where both `'x` and `'b` would have a DB index of 1.
1037 // The substitution from the input trait-ref is therefore going to be
1038 // `'a => 'x` (where `'x` has a DB index of 1).
1039 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1040 // early-bound parameter and `'b' is a late-bound parameter with a
1042 // - If we replace `'a` with `'x` from the input, it too will have
1043 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1044 // just as we wanted.
1046 // There is only one catch. If we just apply the substitution `'a
1047 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1048 // adjust the DB index because we substituting into a binder (it
1049 // tries to be so smart...) resulting in `for<'x> for<'b>
1050 // Bar1<'x,'b>` (we have no syntax for this, so use your
1051 // imagination). Basically the 'x will have DB index of 2 and 'b
1052 // will have DB index of 1. Not quite what we want. So we apply
1053 // the substitution to the *contents* of the trait reference,
1054 // rather than the trait reference itself (put another way, the
1055 // substitution code expects equal binding levels in the values
1056 // from the substitution and the value being substituted into, and
1057 // this trick achieves that).
1059 let substs = &trait_ref.skip_binder().substs;
1061 Predicate::Trait(ref binder) =>
1062 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1063 Predicate::Subtype(ref binder) =>
1064 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1065 Predicate::RegionOutlives(ref binder) =>
1066 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1067 Predicate::TypeOutlives(ref binder) =>
1068 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1069 Predicate::Projection(ref binder) =>
1070 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1071 Predicate::WellFormed(data) =>
1072 Predicate::WellFormed(data.subst(tcx, substs)),
1073 Predicate::ObjectSafe(trait_def_id) =>
1074 Predicate::ObjectSafe(trait_def_id),
1075 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1076 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1077 Predicate::ConstEvaluatable(def_id, const_substs) =>
1078 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1083 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1084 pub struct TraitPredicate<'tcx> {
1085 pub trait_ref: TraitRef<'tcx>
1087 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1089 impl<'tcx> TraitPredicate<'tcx> {
1090 pub fn def_id(&self) -> DefId {
1091 self.trait_ref.def_id
1094 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
1095 self.trait_ref.input_types()
1098 pub fn self_ty(&self) -> Ty<'tcx> {
1099 self.trait_ref.self_ty()
1103 impl<'tcx> PolyTraitPredicate<'tcx> {
1104 pub fn def_id(&self) -> DefId {
1105 // ok to skip binder since trait def-id does not care about regions
1106 self.skip_binder().def_id()
1110 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1111 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
1112 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1113 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>,
1115 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>,
1117 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1118 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1120 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1121 pub struct SubtypePredicate<'tcx> {
1122 pub a_is_expected: bool,
1126 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1128 /// This kind of predicate has no *direct* correspondent in the
1129 /// syntax, but it roughly corresponds to the syntactic forms:
1131 /// 1. `T : TraitRef<..., Item=Type>`
1132 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1134 /// In particular, form #1 is "desugared" to the combination of a
1135 /// normal trait predicate (`T : TraitRef<...>`) and one of these
1136 /// predicates. Form #2 is a broader form in that it also permits
1137 /// equality between arbitrary types. Processing an instance of
1138 /// Form #2 eventually yields one of these `ProjectionPredicate`
1139 /// instances to normalize the LHS.
1140 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1141 pub struct ProjectionPredicate<'tcx> {
1142 pub projection_ty: ProjectionTy<'tcx>,
1146 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1148 impl<'tcx> PolyProjectionPredicate<'tcx> {
1149 /// Returns the def-id of the associated item being projected.
1150 pub fn item_def_id(&self) -> DefId {
1151 self.skip_binder().projection_ty.item_def_id
1154 pub fn to_poly_trait_ref(&self, tcx: TyCtxt) -> PolyTraitRef<'tcx> {
1155 // Note: unlike with TraitRef::to_poly_trait_ref(),
1156 // self.0.trait_ref is permitted to have escaping regions.
1157 // This is because here `self` has a `Binder` and so does our
1158 // return value, so we are preserving the number of binding
1160 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1163 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1164 self.map_bound(|predicate| predicate.ty)
1167 /// The DefId of the TraitItem for the associated type.
1169 /// Note that this is not the DefId of the TraitRef containing this
1170 /// associated type, which is in tcx.associated_item(projection_def_id()).container.
1171 pub fn projection_def_id(&self) -> DefId {
1172 // ok to skip binder since trait def-id does not care about regions
1173 self.skip_binder().projection_ty.item_def_id
1177 pub trait ToPolyTraitRef<'tcx> {
1178 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1181 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1182 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1183 ty::Binder::dummy(self.clone())
1187 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1188 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1189 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1193 pub trait ToPredicate<'tcx> {
1194 fn to_predicate(&self) -> Predicate<'tcx>;
1197 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1198 fn to_predicate(&self) -> Predicate<'tcx> {
1199 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1200 trait_ref: self.clone()
1205 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1206 fn to_predicate(&self) -> Predicate<'tcx> {
1207 ty::Predicate::Trait(self.to_poly_trait_predicate())
1211 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1212 fn to_predicate(&self) -> Predicate<'tcx> {
1213 Predicate::RegionOutlives(self.clone())
1217 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1218 fn to_predicate(&self) -> Predicate<'tcx> {
1219 Predicate::TypeOutlives(self.clone())
1223 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1224 fn to_predicate(&self) -> Predicate<'tcx> {
1225 Predicate::Projection(self.clone())
1229 impl<'tcx> Predicate<'tcx> {
1230 /// Iterates over the types in this predicate. Note that in all
1231 /// cases this is skipping over a binder, so late-bound regions
1232 /// with depth 0 are bound by the predicate.
1233 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1234 let vec: Vec<_> = match *self {
1235 ty::Predicate::Trait(ref data) => {
1236 data.skip_binder().input_types().collect()
1238 ty::Predicate::Subtype(binder) => {
1239 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1242 ty::Predicate::TypeOutlives(binder) => {
1243 vec![binder.skip_binder().0]
1245 ty::Predicate::RegionOutlives(..) => {
1248 ty::Predicate::Projection(ref data) => {
1249 let inner = data.skip_binder();
1250 inner.projection_ty.substs.types().chain(Some(inner.ty)).collect()
1252 ty::Predicate::WellFormed(data) => {
1255 ty::Predicate::ObjectSafe(_trait_def_id) => {
1258 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1259 closure_substs.substs.types().collect()
1261 ty::Predicate::ConstEvaluatable(_, substs) => {
1262 substs.types().collect()
1266 // The only reason to collect into a vector here is that I was
1267 // too lazy to make the full (somewhat complicated) iterator
1268 // type that would be needed here. But I wanted this fn to
1269 // return an iterator conceptually, rather than a `Vec`, so as
1270 // to be closer to `Ty::walk`.
1274 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1276 Predicate::Trait(ref t) => {
1277 Some(t.to_poly_trait_ref())
1279 Predicate::Projection(..) |
1280 Predicate::Subtype(..) |
1281 Predicate::RegionOutlives(..) |
1282 Predicate::WellFormed(..) |
1283 Predicate::ObjectSafe(..) |
1284 Predicate::ClosureKind(..) |
1285 Predicate::TypeOutlives(..) |
1286 Predicate::ConstEvaluatable(..) => {
1292 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1294 Predicate::TypeOutlives(data) => {
1297 Predicate::Trait(..) |
1298 Predicate::Projection(..) |
1299 Predicate::Subtype(..) |
1300 Predicate::RegionOutlives(..) |
1301 Predicate::WellFormed(..) |
1302 Predicate::ObjectSafe(..) |
1303 Predicate::ClosureKind(..) |
1304 Predicate::ConstEvaluatable(..) => {
1311 /// Represents the bounds declared on a particular set of type
1312 /// parameters. Should eventually be generalized into a flag list of
1313 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1314 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1315 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1316 /// the `GenericPredicates` are expressed in terms of the bound type
1317 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1318 /// represented a set of bounds for some particular instantiation,
1319 /// meaning that the generic parameters have been substituted with
1324 /// struct Foo<T,U:Bar<T>> { ... }
1326 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1327 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1328 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1329 /// [usize:Bar<isize>]]`.
1331 pub struct InstantiatedPredicates<'tcx> {
1332 pub predicates: Vec<Predicate<'tcx>>,
1335 impl<'tcx> InstantiatedPredicates<'tcx> {
1336 pub fn empty() -> InstantiatedPredicates<'tcx> {
1337 InstantiatedPredicates { predicates: vec![] }
1340 pub fn is_empty(&self) -> bool {
1341 self.predicates.is_empty()
1345 /// "Universes" are used during type- and trait-checking in the
1346 /// presence of `for<..>` binders to control what sets of names are
1347 /// visible. Universes are arranged into a tree: the root universe
1348 /// contains names that are always visible. But when you enter into
1349 /// some subuniverse, then it may add names that are only visible
1350 /// within that subtree (but it can still name the names of its
1351 /// ancestor universes).
1353 /// To make this more concrete, consider this program:
1357 /// fn bar<T>(x: T) {
1358 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1362 /// The struct name `Foo` is in the root universe U0. But the type
1363 /// parameter `T`, introduced on `bar`, is in a subuniverse U1 --
1364 /// i.e., within `bar`, we can name both `T` and `Foo`, but outside of
1365 /// `bar`, we cannot name `T`. Then, within the type of `y`, the
1366 /// region `'a` is in a subuniverse U2 of U1, because we can name it
1367 /// inside the fn type but not outside.
1369 /// Universes are related to **skolemization** -- which is a way of
1370 /// doing type- and trait-checking around these "forall" binders (also
1371 /// called **universal quantification**). The idea is that when, in
1372 /// the body of `bar`, we refer to `T` as a type, we aren't referring
1373 /// to any type in particular, but rather a kind of "fresh" type that
1374 /// is distinct from all other types we have actually declared. This
1375 /// is called a **skolemized** type, and we use universes to talk
1376 /// about this. In other words, a type name in universe 0 always
1377 /// corresponds to some "ground" type that the user declared, but a
1378 /// type name in a non-zero universe is a skolemized type -- an
1379 /// idealized representative of "types in general" that we use for
1380 /// checking generic functions.
1381 #[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
1382 pub struct UniverseIndex(u32);
1384 impl UniverseIndex {
1385 /// The root universe, where things that the user defined are
1387 pub const ROOT: Self = UniverseIndex(0);
1389 /// A "subuniverse" corresponds to being inside a `forall` quantifier.
1390 /// So, for example, suppose we have this type in universe `U`:
1393 /// for<'a> fn(&'a u32)
1396 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1397 /// subuniverse of `U` -- in this new universe, we can name the
1398 /// region `'a`, but that region was not nameable from `U` because
1399 /// it was not in scope there.
1400 pub fn subuniverse(self) -> UniverseIndex {
1401 UniverseIndex(self.0.checked_add(1).unwrap())
1404 pub fn as_u32(&self) -> u32 {
1408 pub fn as_usize(&self) -> usize {
1413 impl From<u32> for UniverseIndex {
1414 fn from(index: u32) -> Self {
1415 UniverseIndex(index)
1419 /// When type checking, we use the `ParamEnv` to track
1420 /// details about the set of where-clauses that are in scope at this
1421 /// particular point.
1422 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1423 pub struct ParamEnv<'tcx> {
1424 /// Obligations that the caller must satisfy. This is basically
1425 /// the set of bounds on the in-scope type parameters, translated
1426 /// into Obligations, and elaborated and normalized.
1427 pub caller_bounds: &'tcx Slice<ty::Predicate<'tcx>>,
1429 /// Typically, this is `Reveal::UserFacing`, but during trans we
1430 /// want `Reveal::All` -- note that this is always paired with an
1431 /// empty environment. To get that, use `ParamEnv::reveal()`.
1432 pub reveal: traits::Reveal,
1435 impl<'tcx> ParamEnv<'tcx> {
1436 /// Construct a trait environment suitable for contexts where
1437 /// there are no where clauses in scope. Hidden types (like `impl
1438 /// Trait`) are left hidden, so this is suitable for ordinary
1440 pub fn empty() -> Self {
1441 Self::new(ty::Slice::empty(), Reveal::UserFacing)
1444 /// Construct a trait environment with no where clauses in scope
1445 /// where the values of all `impl Trait` and other hidden types
1446 /// are revealed. This is suitable for monomorphized, post-typeck
1447 /// environments like trans or doing optimizations.
1449 /// NB. If you want to have predicates in scope, use `ParamEnv::new`,
1450 /// or invoke `param_env.with_reveal_all()`.
1451 pub fn reveal_all() -> Self {
1452 Self::new(ty::Slice::empty(), Reveal::All)
1455 /// Construct a trait environment with the given set of predicates.
1456 pub fn new(caller_bounds: &'tcx ty::Slice<ty::Predicate<'tcx>>,
1459 ty::ParamEnv { caller_bounds, reveal }
1462 /// Returns a new parameter environment with the same clauses, but
1463 /// which "reveals" the true results of projections in all cases
1464 /// (even for associated types that are specializable). This is
1465 /// the desired behavior during trans and certain other special
1466 /// contexts; normally though we want to use `Reveal::UserFacing`,
1467 /// which is the default.
1468 pub fn with_reveal_all(self) -> Self {
1469 ty::ParamEnv { reveal: Reveal::All, ..self }
1472 /// Returns this same environment but with no caller bounds.
1473 pub fn without_caller_bounds(self) -> Self {
1474 ty::ParamEnv { caller_bounds: ty::Slice::empty(), ..self }
1477 /// Creates a suitable environment in which to perform trait
1478 /// queries on the given value. When type-checking, this is simply
1479 /// the pair of the environment plus value. But when reveal is set to
1480 /// All, then if `value` does not reference any type parameters, we will
1481 /// pair it with the empty environment. This improves caching and is generally
1484 /// NB: We preserve the environment when type-checking because it
1485 /// is possible for the user to have wacky where-clauses like
1486 /// `where Box<u32>: Copy`, which are clearly never
1487 /// satisfiable. We generally want to behave as if they were true,
1488 /// although the surrounding function is never reachable.
1489 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1491 Reveal::UserFacing => {
1500 || value.needs_infer()
1501 || value.has_param_types()
1502 || value.has_self_ty()
1510 param_env: self.without_caller_bounds(),
1519 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1520 pub struct ParamEnvAnd<'tcx, T> {
1521 pub param_env: ParamEnv<'tcx>,
1525 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1526 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1527 (self.param_env, self.value)
1531 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'gcx, T>
1532 where T: HashStable<StableHashingContext<'a>>
1534 fn hash_stable<W: StableHasherResult>(&self,
1535 hcx: &mut StableHashingContext<'a>,
1536 hasher: &mut StableHasher<W>) {
1542 param_env.hash_stable(hcx, hasher);
1543 value.hash_stable(hcx, hasher);
1547 #[derive(Copy, Clone, Debug)]
1548 pub struct Destructor {
1549 /// The def-id of the destructor method
1554 pub struct AdtFlags: u32 {
1555 const NO_ADT_FLAGS = 0;
1556 const IS_ENUM = 1 << 0;
1557 const IS_PHANTOM_DATA = 1 << 1;
1558 const IS_FUNDAMENTAL = 1 << 2;
1559 const IS_UNION = 1 << 3;
1560 const IS_BOX = 1 << 4;
1561 /// Indicates whether this abstract data type will be expanded on in future (new
1562 /// fields/variants) and as such, whether downstream crates must match exhaustively on the
1563 /// fields/variants of this data type.
1565 /// See RFC 2008 (<https://github.com/rust-lang/rfcs/pull/2008>).
1566 const IS_NON_EXHAUSTIVE = 1 << 5;
1571 pub struct VariantDef {
1572 /// The variant's DefId. If this is a tuple-like struct,
1573 /// this is the DefId of the struct's ctor.
1575 pub name: Name, // struct's name if this is a struct
1576 pub discr: VariantDiscr,
1577 pub fields: Vec<FieldDef>,
1578 pub ctor_kind: CtorKind,
1581 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1582 pub enum VariantDiscr {
1583 /// Explicit value for this variant, i.e. `X = 123`.
1584 /// The `DefId` corresponds to the embedded constant.
1587 /// The previous variant's discriminant plus one.
1588 /// For efficiency reasons, the distance from the
1589 /// last `Explicit` discriminant is being stored,
1590 /// or `0` for the first variant, if it has none.
1595 pub struct FieldDef {
1598 pub vis: Visibility,
1601 /// The definition of an abstract data type - a struct or enum.
1603 /// These are all interned (by intern_adt_def) into the adt_defs
1607 pub variants: Vec<VariantDef>,
1609 pub repr: ReprOptions,
1612 impl PartialEq for AdtDef {
1613 // AdtDef are always interned and this is part of TyS equality
1615 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1618 impl Eq for AdtDef {}
1620 impl Hash for AdtDef {
1622 fn hash<H: Hasher>(&self, s: &mut H) {
1623 (self as *const AdtDef).hash(s)
1627 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1628 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1633 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1636 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1637 fn hash_stable<W: StableHasherResult>(&self,
1638 hcx: &mut StableHashingContext<'a>,
1639 hasher: &mut StableHasher<W>) {
1641 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> =
1642 RefCell::new(FxHashMap());
1645 let hash: Fingerprint = CACHE.with(|cache| {
1646 let addr = self as *const AdtDef as usize;
1647 *cache.borrow_mut().entry(addr).or_insert_with(|| {
1655 let mut hasher = StableHasher::new();
1656 did.hash_stable(hcx, &mut hasher);
1657 variants.hash_stable(hcx, &mut hasher);
1658 flags.hash_stable(hcx, &mut hasher);
1659 repr.hash_stable(hcx, &mut hasher);
1665 hash.hash_stable(hcx, hasher);
1669 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
1670 pub enum AdtKind { Struct, Union, Enum }
1673 #[derive(RustcEncodable, RustcDecodable, Default)]
1674 pub struct ReprFlags: u8 {
1675 const IS_C = 1 << 0;
1676 const IS_SIMD = 1 << 1;
1677 const IS_TRANSPARENT = 1 << 2;
1678 // Internal only for now. If true, don't reorder fields.
1679 const IS_LINEAR = 1 << 3;
1681 // Any of these flags being set prevent field reordering optimisation.
1682 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1683 ReprFlags::IS_SIMD.bits |
1684 ReprFlags::IS_LINEAR.bits;
1688 impl_stable_hash_for!(struct ReprFlags {
1694 /// Represents the repr options provided by the user,
1695 #[derive(Copy, Clone, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1696 pub struct ReprOptions {
1697 pub int: Option<attr::IntType>,
1700 pub flags: ReprFlags,
1703 impl_stable_hash_for!(struct ReprOptions {
1711 pub fn new(tcx: TyCtxt, did: DefId) -> ReprOptions {
1712 let mut flags = ReprFlags::empty();
1713 let mut size = None;
1714 let mut max_align = 0;
1715 let mut min_pack = 0;
1716 for attr in tcx.get_attrs(did).iter() {
1717 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1718 flags.insert(match r {
1719 attr::ReprC => ReprFlags::IS_C,
1720 attr::ReprPacked(pack) => {
1721 min_pack = if min_pack > 0 {
1722 cmp::min(pack, min_pack)
1728 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
1729 attr::ReprSimd => ReprFlags::IS_SIMD,
1730 attr::ReprInt(i) => {
1734 attr::ReprAlign(align) => {
1735 max_align = cmp::max(align, max_align);
1742 // This is here instead of layout because the choice must make it into metadata.
1743 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1744 flags.insert(ReprFlags::IS_LINEAR);
1746 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
1750 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1752 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1754 pub fn packed(&self) -> bool { self.pack > 0 }
1756 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
1758 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1760 pub fn discr_type(&self) -> attr::IntType {
1761 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
1764 /// Returns true if this `#[repr()]` should inhabit "smart enum
1765 /// layout" optimizations, such as representing `Foo<&T>` as a
1767 pub fn inhibit_enum_layout_opt(&self) -> bool {
1768 self.c() || self.int.is_some()
1771 /// Returns true if this `#[repr()]` should inhibit struct field reordering
1772 /// optimizations, such as with repr(C) or repr(packed(1)).
1773 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
1774 !(self.flags & ReprFlags::IS_UNOPTIMISABLE).is_empty() || (self.pack == 1)
1778 impl<'a, 'gcx, 'tcx> AdtDef {
1782 variants: Vec<VariantDef>,
1783 repr: ReprOptions) -> Self {
1784 let mut flags = AdtFlags::NO_ADT_FLAGS;
1785 let attrs = tcx.get_attrs(did);
1786 if attr::contains_name(&attrs, "fundamental") {
1787 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1789 if Some(did) == tcx.lang_items().phantom_data() {
1790 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1792 if Some(did) == tcx.lang_items().owned_box() {
1793 flags = flags | AdtFlags::IS_BOX;
1795 if tcx.has_attr(did, "non_exhaustive") {
1796 flags = flags | AdtFlags::IS_NON_EXHAUSTIVE;
1799 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
1800 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
1801 AdtKind::Struct => {}
1812 pub fn is_struct(&self) -> bool {
1813 !self.is_union() && !self.is_enum()
1817 pub fn is_union(&self) -> bool {
1818 self.flags.intersects(AdtFlags::IS_UNION)
1822 pub fn is_enum(&self) -> bool {
1823 self.flags.intersects(AdtFlags::IS_ENUM)
1827 pub fn is_non_exhaustive(&self) -> bool {
1828 self.flags.intersects(AdtFlags::IS_NON_EXHAUSTIVE)
1831 /// Returns the kind of the ADT - Struct or Enum.
1833 pub fn adt_kind(&self) -> AdtKind {
1836 } else if self.is_union() {
1843 pub fn descr(&self) -> &'static str {
1844 match self.adt_kind() {
1845 AdtKind::Struct => "struct",
1846 AdtKind::Union => "union",
1847 AdtKind::Enum => "enum",
1851 pub fn variant_descr(&self) -> &'static str {
1852 match self.adt_kind() {
1853 AdtKind::Struct => "struct",
1854 AdtKind::Union => "union",
1855 AdtKind::Enum => "variant",
1859 /// Returns whether this type is #[fundamental] for the purposes
1860 /// of coherence checking.
1862 pub fn is_fundamental(&self) -> bool {
1863 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
1866 /// Returns true if this is PhantomData<T>.
1868 pub fn is_phantom_data(&self) -> bool {
1869 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
1872 /// Returns true if this is Box<T>.
1874 pub fn is_box(&self) -> bool {
1875 self.flags.intersects(AdtFlags::IS_BOX)
1878 /// Returns whether this type has a destructor.
1879 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
1880 self.destructor(tcx).is_some()
1883 /// Asserts this is a struct or union and returns its unique variant.
1884 pub fn non_enum_variant(&self) -> &VariantDef {
1885 assert!(self.is_struct() || self.is_union());
1890 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
1891 tcx.predicates_of(self.did)
1894 /// Returns an iterator over all fields contained
1897 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
1898 self.variants.iter().flat_map(|v| v.fields.iter())
1901 pub fn is_payloadfree(&self) -> bool {
1902 !self.variants.is_empty() &&
1903 self.variants.iter().all(|v| v.fields.is_empty())
1906 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
1909 .find(|v| v.did == vid)
1910 .expect("variant_with_id: unknown variant")
1913 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1916 .position(|v| v.did == vid)
1917 .expect("variant_index_with_id: unknown variant")
1920 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
1922 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
1923 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
1924 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.non_enum_variant(),
1925 _ => bug!("unexpected def {:?} in variant_of_def", def)
1930 pub fn eval_explicit_discr(
1932 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1934 ) -> Option<Discr<'tcx>> {
1935 let param_env = ParamEnv::empty();
1936 let repr_type = self.repr.discr_type();
1937 let substs = Substs::identity_for_item(tcx.global_tcx(), expr_did);
1938 let instance = ty::Instance::new(expr_did, substs);
1939 let cid = GlobalId {
1943 match tcx.const_eval(param_env.and(cid)) {
1945 // FIXME: Find the right type and use it instead of `val.ty` here
1946 if let Some(b) = val.assert_bits(val.ty) {
1947 trace!("discriminants: {} ({:?})", b, repr_type);
1953 info!("invalid enum discriminant: {:#?}", val);
1954 ::middle::const_val::struct_error(
1956 tcx.def_span(expr_did),
1957 "constant evaluation of enum discriminant resulted in non-integer",
1963 err.report(tcx, tcx.def_span(expr_did), "enum discriminant");
1964 if !expr_did.is_local() {
1965 span_bug!(tcx.def_span(expr_did),
1966 "variant discriminant evaluation succeeded \
1967 in its crate but failed locally");
1975 pub fn discriminants(
1977 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1978 ) -> impl Iterator<Item=Discr<'tcx>> + Captures<'gcx> + 'a {
1979 let repr_type = self.repr.discr_type();
1980 let initial = repr_type.initial_discriminant(tcx.global_tcx());
1981 let mut prev_discr = None::<Discr<'tcx>>;
1982 self.variants.iter().map(move |v| {
1983 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
1984 if let VariantDiscr::Explicit(expr_did) = v.discr {
1985 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
1989 prev_discr = Some(discr);
1995 /// Compute the discriminant value used by a specific variant.
1996 /// Unlike `discriminants`, this is (amortized) constant-time,
1997 /// only doing at most one query for evaluating an explicit
1998 /// discriminant (the last one before the requested variant),
1999 /// assuming there are no constant-evaluation errors there.
2000 pub fn discriminant_for_variant(&self,
2001 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2002 variant_index: usize)
2004 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2005 let explicit_value = val
2006 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2007 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx.global_tcx()));
2008 explicit_value.checked_add(tcx, offset as u128).0
2011 /// Yields a DefId for the discriminant and an offset to add to it
2012 /// Alternatively, if there is no explicit discriminant, returns the
2013 /// inferred discriminant directly
2014 pub fn discriminant_def_for_variant(
2016 variant_index: usize,
2017 ) -> (Option<DefId>, usize) {
2018 let mut explicit_index = variant_index;
2021 match self.variants[explicit_index].discr {
2022 ty::VariantDiscr::Relative(0) => {
2026 ty::VariantDiscr::Relative(distance) => {
2027 explicit_index -= distance;
2029 ty::VariantDiscr::Explicit(did) => {
2030 expr_did = Some(did);
2035 (expr_did, variant_index - explicit_index)
2038 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
2039 tcx.adt_destructor(self.did)
2042 /// Returns a list of types such that `Self: Sized` if and only
2043 /// if that type is Sized, or `TyErr` if this type is recursive.
2045 /// Oddly enough, checking that the sized-constraint is Sized is
2046 /// actually more expressive than checking all members:
2047 /// the Sized trait is inductive, so an associated type that references
2048 /// Self would prevent its containing ADT from being Sized.
2050 /// Due to normalization being eager, this applies even if
2051 /// the associated type is behind a pointer, e.g. issue #31299.
2052 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
2053 match tcx.try_get_query::<queries::adt_sized_constraint>(DUMMY_SP, self.did) {
2056 debug!("adt_sized_constraint: {:?} is recursive", self);
2057 // This should be reported as an error by `check_representable`.
2059 // Consider the type as Sized in the meanwhile to avoid
2060 // further errors. Delay our `bug` diagnostic here to get
2061 // emitted later as well in case we accidentally otherwise don't
2064 tcx.intern_type_list(&[tcx.types.err])
2069 fn sized_constraint_for_ty(&self,
2070 tcx: TyCtxt<'a, 'tcx, 'tcx>,
2073 let result = match ty.sty {
2074 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
2075 TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
2076 TyArray(..) | TyClosure(..) | TyGenerator(..) | TyNever => {
2085 TyGeneratorWitness(..) => {
2086 // these are never sized - return the target type
2090 TyTuple(ref tys) => {
2093 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
2097 TyAdt(adt, substs) => {
2099 let adt_tys = adt.sized_constraint(tcx);
2100 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
2103 .map(|ty| ty.subst(tcx, substs))
2104 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2108 TyProjection(..) | TyAnon(..) => {
2109 // must calculate explicitly.
2110 // FIXME: consider special-casing always-Sized projections
2115 // perf hack: if there is a `T: Sized` bound, then
2116 // we know that `T` is Sized and do not need to check
2119 let sized_trait = match tcx.lang_items().sized_trait() {
2121 _ => return vec![ty]
2123 let sized_predicate = Binder::dummy(TraitRef {
2124 def_id: sized_trait,
2125 substs: tcx.mk_substs_trait(ty, &[])
2127 let predicates = tcx.predicates_of(self.did).predicates;
2128 if predicates.into_iter().any(|p| p == sized_predicate) {
2136 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2140 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2145 impl<'a, 'gcx, 'tcx> FieldDef {
2146 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
2147 tcx.type_of(self.did).subst(tcx, subst)
2151 /// Represents the various closure traits in the Rust language. This
2152 /// will determine the type of the environment (`self`, in the
2153 /// desuaring) argument that the closure expects.
2155 /// You can get the environment type of a closure using
2156 /// `tcx.closure_env_ty()`.
2157 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
2158 pub enum ClosureKind {
2159 // Warning: Ordering is significant here! The ordering is chosen
2160 // because the trait Fn is a subtrait of FnMut and so in turn, and
2161 // hence we order it so that Fn < FnMut < FnOnce.
2167 impl<'a, 'tcx> ClosureKind {
2168 // This is the initial value used when doing upvar inference.
2169 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2171 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
2173 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
2174 ClosureKind::FnMut => {
2175 tcx.require_lang_item(FnMutTraitLangItem)
2177 ClosureKind::FnOnce => {
2178 tcx.require_lang_item(FnOnceTraitLangItem)
2183 /// True if this a type that impls this closure kind
2184 /// must also implement `other`.
2185 pub fn extends(self, other: ty::ClosureKind) -> bool {
2186 match (self, other) {
2187 (ClosureKind::Fn, ClosureKind::Fn) => true,
2188 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2189 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2190 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2191 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2192 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2197 /// Returns the representative scalar type for this closure kind.
2198 /// See `TyS::to_opt_closure_kind` for more details.
2199 pub fn to_ty(self, tcx: TyCtxt<'_, '_, 'tcx>) -> Ty<'tcx> {
2201 ty::ClosureKind::Fn => tcx.types.i8,
2202 ty::ClosureKind::FnMut => tcx.types.i16,
2203 ty::ClosureKind::FnOnce => tcx.types.i32,
2208 impl<'tcx> TyS<'tcx> {
2209 /// Iterator that walks `self` and any types reachable from
2210 /// `self`, in depth-first order. Note that just walks the types
2211 /// that appear in `self`, it does not descend into the fields of
2212 /// structs or variants. For example:
2215 /// isize => { isize }
2216 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2217 /// [isize] => { [isize], isize }
2219 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2220 TypeWalker::new(self)
2223 /// Iterator that walks the immediate children of `self`. Hence
2224 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2225 /// (but not `i32`, like `walk`).
2226 pub fn walk_shallow(&'tcx self) -> AccIntoIter<walk::TypeWalkerArray<'tcx>> {
2227 walk::walk_shallow(self)
2230 /// Walks `ty` and any types appearing within `ty`, invoking the
2231 /// callback `f` on each type. If the callback returns false, then the
2232 /// children of the current type are ignored.
2234 /// Note: prefer `ty.walk()` where possible.
2235 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2236 where F : FnMut(Ty<'tcx>) -> bool
2238 let mut walker = self.walk();
2239 while let Some(ty) = walker.next() {
2241 walker.skip_current_subtree();
2248 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2250 hir::MutMutable => MutBorrow,
2251 hir::MutImmutable => ImmBorrow,
2255 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2256 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2257 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2259 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2261 MutBorrow => hir::MutMutable,
2262 ImmBorrow => hir::MutImmutable,
2264 // We have no type corresponding to a unique imm borrow, so
2265 // use `&mut`. It gives all the capabilities of an `&uniq`
2266 // and hence is a safe "over approximation".
2267 UniqueImmBorrow => hir::MutMutable,
2271 pub fn to_user_str(&self) -> &'static str {
2273 MutBorrow => "mutable",
2274 ImmBorrow => "immutable",
2275 UniqueImmBorrow => "uniquely immutable",
2280 #[derive(Debug, Clone)]
2281 pub enum Attributes<'gcx> {
2282 Owned(Lrc<[ast::Attribute]>),
2283 Borrowed(&'gcx [ast::Attribute])
2286 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2287 type Target = [ast::Attribute];
2289 fn deref(&self) -> &[ast::Attribute] {
2291 &Attributes::Owned(ref data) => &data,
2292 &Attributes::Borrowed(data) => data
2297 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2298 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2299 self.typeck_tables_of(self.hir.body_owner_def_id(body))
2302 /// Returns an iterator of the def-ids for all body-owners in this
2303 /// crate. If you would prefer to iterate over the bodies
2304 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
2307 ) -> impl Iterator<Item = DefId> + Captures<'tcx> + Captures<'gcx> + 'a {
2311 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
2314 pub fn expr_span(self, id: NodeId) -> Span {
2315 match self.hir.find(id) {
2316 Some(hir_map::NodeExpr(e)) => {
2320 bug!("Node id {} is not an expr: {:?}", id, f);
2323 bug!("Node id {} is not present in the node map", id);
2328 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2329 self.associated_items(id)
2330 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2334 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2335 self.associated_items(did).any(|item| {
2336 item.relevant_for_never()
2340 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2341 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2342 match self.hir.get(node_id) {
2343 hir_map::NodeTraitItem(_) | hir_map::NodeImplItem(_) => true,
2347 match self.describe_def(def_id).expect("no def for def-id") {
2348 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2353 if is_associated_item {
2354 Some(self.associated_item(def_id))
2360 fn associated_item_from_trait_item_ref(self,
2361 parent_def_id: DefId,
2362 parent_vis: &hir::Visibility,
2363 trait_item_ref: &hir::TraitItemRef)
2365 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2366 let (kind, has_self) = match trait_item_ref.kind {
2367 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2368 hir::AssociatedItemKind::Method { has_self } => {
2369 (ty::AssociatedKind::Method, has_self)
2371 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2375 name: trait_item_ref.name,
2377 // Visibility of trait items is inherited from their traits.
2378 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2379 defaultness: trait_item_ref.defaultness,
2381 container: TraitContainer(parent_def_id),
2382 method_has_self_argument: has_self
2386 fn associated_item_from_impl_item_ref(self,
2387 parent_def_id: DefId,
2388 impl_item_ref: &hir::ImplItemRef)
2390 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2391 let (kind, has_self) = match impl_item_ref.kind {
2392 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2393 hir::AssociatedItemKind::Method { has_self } => {
2394 (ty::AssociatedKind::Method, has_self)
2396 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2399 ty::AssociatedItem {
2400 name: impl_item_ref.name,
2402 // Visibility of trait impl items doesn't matter.
2403 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2404 defaultness: impl_item_ref.defaultness,
2406 container: ImplContainer(parent_def_id),
2407 method_has_self_argument: has_self
2411 pub fn field_index(self, node_id: NodeId, tables: &TypeckTables) -> usize {
2412 let hir_id = self.hir.node_to_hir_id(node_id);
2413 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2416 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2417 variant.fields.iter().position(|field| {
2418 self.adjust_ident(ident.modern(), variant.did, DUMMY_NODE_ID).0 == field.name.to_ident()
2422 pub fn associated_items(
2425 ) -> impl Iterator<Item = ty::AssociatedItem> + 'a {
2426 let def_ids = self.associated_item_def_ids(def_id);
2427 Box::new((0..def_ids.len()).map(move |i| self.associated_item(def_ids[i])))
2428 as Box<dyn Iterator<Item = ty::AssociatedItem> + 'a>
2431 /// Returns true if the impls are the same polarity and are implementing
2432 /// a trait which contains no items
2433 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2434 if !self.features().overlapping_marker_traits {
2437 let trait1_is_empty = self.impl_trait_ref(def_id1)
2438 .map_or(false, |trait_ref| {
2439 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2441 let trait2_is_empty = self.impl_trait_ref(def_id2)
2442 .map_or(false, |trait_ref| {
2443 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2445 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2450 // Returns `ty::VariantDef` if `def` refers to a struct,
2451 // or variant or their constructors, panics otherwise.
2452 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2454 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2455 let enum_did = self.parent_def_id(did).unwrap();
2456 self.adt_def(enum_did).variant_with_id(did)
2458 Def::Struct(did) | Def::Union(did) => {
2459 self.adt_def(did).non_enum_variant()
2461 Def::StructCtor(ctor_did, ..) => {
2462 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2463 self.adt_def(did).non_enum_variant()
2465 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2469 /// Given a `VariantDef`, returns the def-id of the `AdtDef` of which it is a part.
2470 pub fn adt_def_id_of_variant(self, variant_def: &'tcx VariantDef) -> DefId {
2471 let def_key = self.def_key(variant_def.did);
2472 match def_key.disambiguated_data.data {
2473 // for enum variants and tuple structs, the def-id of the ADT itself
2474 // is the *parent* of the variant
2475 DefPathData::EnumVariant(..) | DefPathData::StructCtor =>
2476 DefId { krate: variant_def.did.krate, index: def_key.parent.unwrap() },
2478 // otherwise, for structs and unions, they share a def-id
2479 _ => variant_def.did,
2483 pub fn item_name(self, id: DefId) -> InternedString {
2484 if id.index == CRATE_DEF_INDEX {
2485 self.original_crate_name(id.krate).as_interned_str()
2487 let def_key = self.def_key(id);
2488 // The name of a StructCtor is that of its struct parent.
2489 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2490 self.item_name(DefId {
2492 index: def_key.parent.unwrap()
2495 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2496 bug!("item_name: no name for {:?}", self.def_path(id));
2502 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2503 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2507 ty::InstanceDef::Item(did) => {
2508 self.optimized_mir(did)
2510 ty::InstanceDef::Intrinsic(..) |
2511 ty::InstanceDef::FnPtrShim(..) |
2512 ty::InstanceDef::Virtual(..) |
2513 ty::InstanceDef::ClosureOnceShim { .. } |
2514 ty::InstanceDef::DropGlue(..) |
2515 ty::InstanceDef::CloneShim(..) => {
2516 self.mir_shims(instance)
2521 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2522 /// Returns None if there is no MIR for the DefId
2523 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2524 if self.is_mir_available(did) {
2525 Some(self.optimized_mir(did))
2531 /// Get the attributes of a definition.
2532 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2533 if let Some(id) = self.hir.as_local_node_id(did) {
2534 Attributes::Borrowed(self.hir.attrs(id))
2536 Attributes::Owned(self.item_attrs(did))
2540 /// Determine whether an item is annotated with an attribute
2541 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2542 attr::contains_name(&self.get_attrs(did), attr)
2545 /// Returns true if this is an `auto trait`.
2546 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
2547 self.trait_def(trait_def_id).has_auto_impl
2550 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
2551 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
2554 /// Given the def_id of an impl, return the def_id of the trait it implements.
2555 /// If it implements no trait, return `None`.
2556 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2557 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2560 /// If the given def ID describes a method belonging to an impl, return the
2561 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2562 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2563 let item = if def_id.krate != LOCAL_CRATE {
2564 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2565 Some(self.associated_item(def_id))
2570 self.opt_associated_item(def_id)
2574 Some(trait_item) => {
2575 match trait_item.container {
2576 TraitContainer(_) => None,
2577 ImplContainer(def_id) => Some(def_id),
2584 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2585 /// with the name of the crate containing the impl.
2586 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2587 if impl_did.is_local() {
2588 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2589 Ok(self.hir.span(node_id))
2591 Err(self.crate_name(impl_did.krate))
2595 // Hygienically compare a use-site name (`use_name`) for a field or an associated item with its
2596 // supposed definition name (`def_name`). The method also needs `DefId` of the supposed
2597 // definition's parent/scope to perform comparison.
2598 pub fn hygienic_eq(self, use_name: Name, def_name: Name, def_parent_def_id: DefId) -> bool {
2599 self.adjust(use_name, def_parent_def_id, DUMMY_NODE_ID).0 == def_name.to_ident()
2602 pub fn adjust(self, name: Name, scope: DefId, block: NodeId) -> (Ident, DefId) {
2603 self.adjust_ident(name.to_ident(), scope, block)
2606 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
2607 let expansion = match scope.krate {
2608 LOCAL_CRATE => self.hir.definitions().expansion(scope.index),
2611 let scope = match ident.span.adjust(expansion) {
2612 Some(macro_def) => self.hir.definitions().macro_def_scope(macro_def),
2613 None if block == DUMMY_NODE_ID => DefId::local(CRATE_DEF_INDEX), // Dummy DefId
2614 None => self.hir.get_module_parent(block),
2620 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2621 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2622 F: FnOnce(&[hir::Freevar]) -> T,
2624 let def_id = self.hir.local_def_id(fid);
2625 match self.freevars(def_id) {
2632 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
2635 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2636 let parent_id = tcx.hir.get_parent(id);
2637 let parent_def_id = tcx.hir.local_def_id(parent_id);
2638 let parent_item = tcx.hir.expect_item(parent_id);
2639 match parent_item.node {
2640 hir::ItemImpl(.., ref impl_item_refs) => {
2641 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2642 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2644 debug_assert_eq!(assoc_item.def_id, def_id);
2649 hir::ItemTrait(.., ref trait_item_refs) => {
2650 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2651 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2654 debug_assert_eq!(assoc_item.def_id, def_id);
2662 span_bug!(parent_item.span,
2663 "unexpected parent of trait or impl item or item not found: {:?}",
2667 /// Calculates the Sized-constraint.
2669 /// In fact, there are only a few options for the types in the constraint:
2670 /// - an obviously-unsized type
2671 /// - a type parameter or projection whose Sizedness can't be known
2672 /// - a tuple of type parameters or projections, if there are multiple
2674 /// - a TyError, if a type contained itself. The representability
2675 /// check should catch this case.
2676 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2678 -> &'tcx [Ty<'tcx>] {
2679 let def = tcx.adt_def(def_id);
2681 let result = tcx.intern_type_list(&def.variants.iter().flat_map(|v| {
2684 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2685 }).collect::<Vec<_>>());
2687 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2692 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2694 -> Lrc<Vec<DefId>> {
2695 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2696 let item = tcx.hir.expect_item(id);
2697 let vec: Vec<_> = match item.node {
2698 hir::ItemTrait(.., ref trait_item_refs) => {
2699 trait_item_refs.iter()
2700 .map(|trait_item_ref| trait_item_ref.id)
2701 .map(|id| tcx.hir.local_def_id(id.node_id))
2704 hir::ItemImpl(.., ref impl_item_refs) => {
2705 impl_item_refs.iter()
2706 .map(|impl_item_ref| impl_item_ref.id)
2707 .map(|id| tcx.hir.local_def_id(id.node_id))
2710 hir::ItemTraitAlias(..) => vec![],
2711 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2716 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
2717 tcx.hir.span_if_local(def_id).unwrap()
2720 /// If the given def ID describes an item belonging to a trait,
2721 /// return the ID of the trait that the trait item belongs to.
2722 /// Otherwise, return `None`.
2723 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
2724 tcx.opt_associated_item(def_id)
2725 .and_then(|associated_item| {
2726 match associated_item.container {
2727 TraitContainer(def_id) => Some(def_id),
2728 ImplContainer(_) => None
2733 /// See `ParamEnv` struct def'n for details.
2734 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2737 // Compute the bounds on Self and the type parameters.
2739 let bounds = tcx.predicates_of(def_id).instantiate_identity(tcx);
2740 let predicates = bounds.predicates;
2742 // Finally, we have to normalize the bounds in the environment, in
2743 // case they contain any associated type projections. This process
2744 // can yield errors if the put in illegal associated types, like
2745 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2746 // report these errors right here; this doesn't actually feel
2747 // right to me, because constructing the environment feels like a
2748 // kind of a "idempotent" action, but I'm not sure where would be
2749 // a better place. In practice, we construct environments for
2750 // every fn once during type checking, and we'll abort if there
2751 // are any errors at that point, so after type checking you can be
2752 // sure that this will succeed without errors anyway.
2754 let unnormalized_env = ty::ParamEnv::new(tcx.intern_predicates(&predicates),
2755 traits::Reveal::UserFacing);
2757 let body_id = tcx.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
2758 tcx.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_id)
2760 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
2761 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
2764 fn crate_disambiguator<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2765 crate_num: CrateNum) -> CrateDisambiguator {
2766 assert_eq!(crate_num, LOCAL_CRATE);
2767 tcx.sess.local_crate_disambiguator()
2770 fn original_crate_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2771 crate_num: CrateNum) -> Symbol {
2772 assert_eq!(crate_num, LOCAL_CRATE);
2773 tcx.crate_name.clone()
2776 fn crate_hash<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2777 crate_num: CrateNum)
2779 assert_eq!(crate_num, LOCAL_CRATE);
2783 fn instance_def_size_estimate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2784 instance_def: InstanceDef<'tcx>)
2786 match instance_def {
2787 InstanceDef::Item(..) |
2788 InstanceDef::DropGlue(..) => {
2789 let mir = tcx.instance_mir(instance_def);
2790 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
2792 // Estimate the size of other compiler-generated shims to be 1.
2797 pub fn provide(providers: &mut ty::maps::Providers) {
2798 context::provide(providers);
2799 erase_regions::provide(providers);
2800 layout::provide(providers);
2801 util::provide(providers);
2802 *providers = ty::maps::Providers {
2804 associated_item_def_ids,
2805 adt_sized_constraint,
2809 crate_disambiguator,
2810 original_crate_name,
2812 trait_impls_of: trait_def::trait_impls_of_provider,
2813 instance_def_size_estimate,
2818 /// A map for the local crate mapping each type to a vector of its
2819 /// inherent impls. This is not meant to be used outside of coherence;
2820 /// rather, you should request the vector for a specific type via
2821 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2822 /// (constructing this map requires touching the entire crate).
2823 #[derive(Clone, Debug)]
2824 pub struct CrateInherentImpls {
2825 pub inherent_impls: DefIdMap<Lrc<Vec<DefId>>>,
2828 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
2829 pub struct SymbolName {
2830 // FIXME: we don't rely on interning or equality here - better have
2831 // this be a `&'tcx str`.
2832 pub name: InternedString
2835 impl_stable_hash_for!(struct self::SymbolName {
2840 pub fn new(name: &str) -> SymbolName {
2842 name: Symbol::intern(name).as_interned_str()
2846 pub fn as_str(&self) -> LocalInternedString {
2851 impl fmt::Display for SymbolName {
2852 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2853 fmt::Display::fmt(&self.name, fmt)
2857 impl fmt::Debug for SymbolName {
2858 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2859 fmt::Display::fmt(&self.name, fmt)