1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 pub use self::Variance::*;
12 pub use self::AssociatedItemContainer::*;
13 pub use self::BorrowKind::*;
14 pub use self::IntVarValue::*;
15 pub use self::LvaluePreference::*;
16 pub use self::fold::TypeFoldable;
18 use dep_graph::DepNode;
19 use hir::{map as hir_map, FreevarMap, TraitMap};
20 use hir::def::{Def, CtorKind, ExportMap};
21 use hir::def_id::{CrateNum, DefId, DefIndex, CRATE_DEF_INDEX, LOCAL_CRATE};
22 use ich::{self, StableHashingContext};
23 use middle::const_val::ConstVal;
24 use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
25 use middle::privacy::AccessLevels;
26 use middle::resolve_lifetime::ObjectLifetimeDefault;
27 use middle::region::CodeExtent;
31 use ty::subst::{Subst, Substs};
32 use ty::util::IntTypeExt;
33 use ty::walk::TypeWalker;
34 use util::common::ErrorReported;
35 use util::nodemap::{NodeSet, DefIdMap, FxHashMap, FxHashSet};
37 use serialize::{self, Encodable, Encoder};
39 use std::collections::BTreeMap;
42 use std::hash::{Hash, Hasher};
43 use std::iter::FromIterator;
47 use std::vec::IntoIter;
49 use syntax::ast::{self, DUMMY_NODE_ID, Name, NodeId};
51 use syntax::symbol::{Symbol, InternedString};
52 use syntax_pos::{DUMMY_SP, Span};
53 use rustc_const_math::ConstInt;
55 use rustc_data_structures::accumulate_vec::IntoIter as AccIntoIter;
56 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
58 use rustc_data_structures::transitive_relation::TransitiveRelation;
62 pub use self::sty::{Binder, DebruijnIndex};
63 pub use self::sty::{FnSig, PolyFnSig};
64 pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
65 pub use self::sty::{ClosureSubsts, TypeAndMut};
66 pub use self::sty::{TraitRef, TypeVariants, PolyTraitRef};
67 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
68 pub use self::sty::{ExistentialProjection, PolyExistentialProjection};
69 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
70 pub use self::sty::RegionKind;
71 pub use self::sty::Issue32330;
72 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid, SkolemizedRegionVid};
73 pub use self::sty::BoundRegion::*;
74 pub use self::sty::InferTy::*;
75 pub use self::sty::RegionKind::*;
76 pub use self::sty::TypeVariants::*;
78 pub use self::context::{TyCtxt, GlobalArenas, tls};
79 pub use self::context::{Lift, TypeckTables};
81 pub use self::instance::{Instance, InstanceDef};
83 pub use self::trait_def::TraitDef;
85 pub use self::maps::queries;
92 pub mod inhabitedness;
109 mod structural_impls;
114 /// The complete set of all analyses described in this module. This is
115 /// produced by the driver and fed to trans and later passes.
117 /// NB: These contents are being migrated into queries using the
118 /// *on-demand* infrastructure.
120 pub struct CrateAnalysis {
121 pub access_levels: Rc<AccessLevels>,
122 pub reachable: Rc<NodeSet>,
124 pub glob_map: Option<hir::GlobMap>,
128 pub struct Resolutions {
129 pub freevars: FreevarMap,
130 pub trait_map: TraitMap,
131 pub maybe_unused_trait_imports: NodeSet,
132 pub export_map: ExportMap,
135 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
136 pub enum AssociatedItemContainer {
137 TraitContainer(DefId),
138 ImplContainer(DefId),
141 impl AssociatedItemContainer {
142 pub fn id(&self) -> DefId {
144 TraitContainer(id) => id,
145 ImplContainer(id) => id,
150 /// The "header" of an impl is everything outside the body: a Self type, a trait
151 /// ref (in the case of a trait impl), and a set of predicates (from the
152 /// bounds/where clauses).
153 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
154 pub struct ImplHeader<'tcx> {
155 pub impl_def_id: DefId,
156 pub self_ty: Ty<'tcx>,
157 pub trait_ref: Option<TraitRef<'tcx>>,
158 pub predicates: Vec<Predicate<'tcx>>,
161 impl<'a, 'gcx, 'tcx> ImplHeader<'tcx> {
162 pub fn with_fresh_ty_vars(selcx: &mut traits::SelectionContext<'a, 'gcx, 'tcx>,
166 let tcx = selcx.tcx();
167 let impl_substs = selcx.infcx().fresh_substs_for_item(DUMMY_SP, impl_def_id);
169 let header = ImplHeader {
170 impl_def_id: impl_def_id,
171 self_ty: tcx.type_of(impl_def_id),
172 trait_ref: tcx.impl_trait_ref(impl_def_id),
173 predicates: tcx.predicates_of(impl_def_id).predicates
174 }.subst(tcx, impl_substs);
176 let traits::Normalized { value: mut header, obligations } =
177 traits::normalize(selcx, traits::ObligationCause::dummy(), &header);
179 header.predicates.extend(obligations.into_iter().map(|o| o.predicate));
184 #[derive(Copy, Clone, Debug)]
185 pub struct AssociatedItem {
188 pub kind: AssociatedKind,
190 pub defaultness: hir::Defaultness,
191 pub container: AssociatedItemContainer,
193 /// Whether this is a method with an explicit self
194 /// as its first argument, allowing method calls.
195 pub method_has_self_argument: bool,
198 #[derive(Copy, Clone, PartialEq, Eq, Debug, RustcEncodable, RustcDecodable)]
199 pub enum AssociatedKind {
205 impl AssociatedItem {
206 pub fn def(&self) -> Def {
208 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
209 AssociatedKind::Method => Def::Method(self.def_id),
210 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
214 /// Tests whether the associated item admits a non-trivial implementation
216 pub fn relevant_for_never<'tcx>(&self) -> bool {
218 AssociatedKind::Const => true,
219 AssociatedKind::Type => true,
220 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
221 AssociatedKind::Method => !self.method_has_self_argument,
226 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
227 pub enum Visibility {
228 /// Visible everywhere (including in other crates).
230 /// Visible only in the given crate-local module.
232 /// Not visible anywhere in the local crate. This is the visibility of private external items.
236 pub trait DefIdTree: Copy {
237 fn parent(self, id: DefId) -> Option<DefId>;
239 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
240 if descendant.krate != ancestor.krate {
244 while descendant != ancestor {
245 match self.parent(descendant) {
246 Some(parent) => descendant = parent,
247 None => return false,
254 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
255 fn parent(self, id: DefId) -> Option<DefId> {
256 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
261 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt) -> Self {
263 hir::Public => Visibility::Public,
264 hir::Visibility::Crate => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
265 hir::Visibility::Restricted { ref path, .. } => match path.def {
266 // If there is no resolution, `resolve` will have already reported an error, so
267 // assume that the visibility is public to avoid reporting more privacy errors.
268 Def::Err => Visibility::Public,
269 def => Visibility::Restricted(def.def_id()),
272 Visibility::Restricted(tcx.hir.local_def_id(tcx.hir.get_module_parent(id)))
277 /// Returns true if an item with this visibility is accessible from the given block.
278 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
279 let restriction = match self {
280 // Public items are visible everywhere.
281 Visibility::Public => return true,
282 // Private items from other crates are visible nowhere.
283 Visibility::Invisible => return false,
284 // Restricted items are visible in an arbitrary local module.
285 Visibility::Restricted(other) if other.krate != module.krate => return false,
286 Visibility::Restricted(module) => module,
289 tree.is_descendant_of(module, restriction)
292 /// Returns true if this visibility is at least as accessible as the given visibility
293 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
294 let vis_restriction = match vis {
295 Visibility::Public => return self == Visibility::Public,
296 Visibility::Invisible => return true,
297 Visibility::Restricted(module) => module,
300 self.is_accessible_from(vis_restriction, tree)
304 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
306 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
307 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
308 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
309 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
312 /// The crate variances map is computed during typeck and contains the
313 /// variance of every item in the local crate. You should not use it
314 /// directly, because to do so will make your pass dependent on the
315 /// HIR of every item in the local crate. Instead, use
316 /// `tcx.variances_of()` to get the variance for a *particular*
318 pub struct CrateVariancesMap {
319 /// This relation tracks the dependencies between the variance of
320 /// various items. In particular, if `a < b`, then the variance of
321 /// `a` depends on the sources of `b`.
322 pub dependencies: TransitiveRelation<DefId>,
324 /// For each item with generics, maps to a vector of the variance
325 /// of its generics. If an item has no generics, it will have no
327 pub variances: FxHashMap<DefId, Rc<Vec<ty::Variance>>>,
329 /// An empty vector, useful for cloning.
330 pub empty_variance: Rc<Vec<ty::Variance>>,
334 /// `a.xform(b)` combines the variance of a context with the
335 /// variance of a type with the following meaning. If we are in a
336 /// context with variance `a`, and we encounter a type argument in
337 /// a position with variance `b`, then `a.xform(b)` is the new
338 /// variance with which the argument appears.
344 /// Here, the "ambient" variance starts as covariant. `*mut T` is
345 /// invariant with respect to `T`, so the variance in which the
346 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
347 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
348 /// respect to its type argument `T`, and hence the variance of
349 /// the `i32` here is `Invariant.xform(Covariant)`, which results
350 /// (again) in `Invariant`.
354 /// fn(*const Vec<i32>, *mut Vec<i32)
356 /// The ambient variance is covariant. A `fn` type is
357 /// contravariant with respect to its parameters, so the variance
358 /// within which both pointer types appear is
359 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
360 /// T` is covariant with respect to `T`, so the variance within
361 /// which the first `Vec<i32>` appears is
362 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
363 /// is true for its `i32` argument. In the `*mut T` case, the
364 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
365 /// and hence the outermost type is `Invariant` with respect to
366 /// `Vec<i32>` (and its `i32` argument).
368 /// Source: Figure 1 of "Taming the Wildcards:
369 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
370 pub fn xform(self, v: ty::Variance) -> ty::Variance {
372 // Figure 1, column 1.
373 (ty::Covariant, ty::Covariant) => ty::Covariant,
374 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
375 (ty::Covariant, ty::Invariant) => ty::Invariant,
376 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
378 // Figure 1, column 2.
379 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
380 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
381 (ty::Contravariant, ty::Invariant) => ty::Invariant,
382 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
384 // Figure 1, column 3.
385 (ty::Invariant, _) => ty::Invariant,
387 // Figure 1, column 4.
388 (ty::Bivariant, _) => ty::Bivariant,
393 #[derive(Clone, Copy, Debug, RustcDecodable, RustcEncodable)]
394 pub struct MethodCallee<'tcx> {
395 /// Impl method ID, for inherent methods, or trait method ID, otherwise.
398 pub substs: &'tcx Substs<'tcx>
401 /// With method calls, we store some extra information in
402 /// side tables (i.e method_map). We use
403 /// MethodCall as a key to index into these tables instead of
404 /// just directly using the expression's NodeId. The reason
405 /// for this being that we may apply adjustments (coercions)
406 /// with the resulting expression also needing to use the
407 /// side tables. The problem with this is that we don't
408 /// assign a separate NodeId to this new expression
409 /// and so it would clash with the base expression if both
410 /// needed to add to the side tables. Thus to disambiguate
411 /// we also keep track of whether there's an adjustment in
413 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
414 pub struct MethodCall {
420 pub fn expr(id: NodeId) -> MethodCall {
427 pub fn autoderef(expr_id: NodeId, autoderef: u32) -> MethodCall {
430 autoderef: 1 + autoderef
435 // maps from an expression id that corresponds to a method call to the details
436 // of the method to be invoked
437 pub type MethodMap<'tcx> = FxHashMap<MethodCall, MethodCallee<'tcx>>;
439 // Contains information needed to resolve types and (in the future) look up
440 // the types of AST nodes.
441 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
442 pub struct CReaderCacheKey {
447 /// Describes the fragment-state associated with a NodeId.
449 /// Currently only unfragmented paths have entries in the table,
450 /// but longer-term this enum is expected to expand to also
451 /// include data for fragmented paths.
452 #[derive(Copy, Clone, Debug)]
453 pub enum FragmentInfo {
454 Moved { var: NodeId, move_expr: NodeId },
455 Assigned { var: NodeId, assign_expr: NodeId, assignee_id: NodeId },
458 // Flags that we track on types. These flags are propagated upwards
459 // through the type during type construction, so that we can quickly
460 // check whether the type has various kinds of types in it without
461 // recursing over the type itself.
463 flags TypeFlags: u32 {
464 const HAS_PARAMS = 1 << 0,
465 const HAS_SELF = 1 << 1,
466 const HAS_TY_INFER = 1 << 2,
467 const HAS_RE_INFER = 1 << 3,
468 const HAS_RE_SKOL = 1 << 4,
469 const HAS_RE_EARLY_BOUND = 1 << 5,
470 const HAS_FREE_REGIONS = 1 << 6,
471 const HAS_TY_ERR = 1 << 7,
472 const HAS_PROJECTION = 1 << 8,
473 const HAS_TY_CLOSURE = 1 << 9,
475 // true if there are "names" of types and regions and so forth
476 // that are local to a particular fn
477 const HAS_LOCAL_NAMES = 1 << 10,
479 // Present if the type belongs in a local type context.
480 // Only set for TyInfer other than Fresh.
481 const KEEP_IN_LOCAL_TCX = 1 << 11,
483 // Is there a projection that does not involve a bound region?
484 // Currently we can't normalize projections w/ bound regions.
485 const HAS_NORMALIZABLE_PROJECTION = 1 << 12,
487 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
488 TypeFlags::HAS_SELF.bits |
489 TypeFlags::HAS_RE_EARLY_BOUND.bits,
491 // Flags representing the nominal content of a type,
492 // computed by FlagsComputation. If you add a new nominal
493 // flag, it should be added here too.
494 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
495 TypeFlags::HAS_SELF.bits |
496 TypeFlags::HAS_TY_INFER.bits |
497 TypeFlags::HAS_RE_INFER.bits |
498 TypeFlags::HAS_RE_SKOL.bits |
499 TypeFlags::HAS_RE_EARLY_BOUND.bits |
500 TypeFlags::HAS_FREE_REGIONS.bits |
501 TypeFlags::HAS_TY_ERR.bits |
502 TypeFlags::HAS_PROJECTION.bits |
503 TypeFlags::HAS_TY_CLOSURE.bits |
504 TypeFlags::HAS_LOCAL_NAMES.bits |
505 TypeFlags::KEEP_IN_LOCAL_TCX.bits,
507 // Caches for type_is_sized, type_moves_by_default
508 const SIZEDNESS_CACHED = 1 << 16,
509 const IS_SIZED = 1 << 17,
510 const FREEZENESS_CACHED = 1 << 20,
511 const IS_FREEZE = 1 << 21,
512 const NEEDS_DROP_CACHED = 1 << 22,
513 const NEEDS_DROP = 1 << 23,
517 pub struct TyS<'tcx> {
518 pub sty: TypeVariants<'tcx>,
519 pub flags: Cell<TypeFlags>,
521 // the maximal depth of any bound regions appearing in this type.
525 impl<'tcx> PartialEq for TyS<'tcx> {
527 fn eq(&self, other: &TyS<'tcx>) -> bool {
528 // (self as *const _) == (other as *const _)
529 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
532 impl<'tcx> Eq for TyS<'tcx> {}
534 impl<'tcx> Hash for TyS<'tcx> {
535 fn hash<H: Hasher>(&self, s: &mut H) {
536 (self as *const TyS).hash(s)
540 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for ty::TyS<'tcx> {
541 fn hash_stable<W: StableHasherResult>(&self,
542 hcx: &mut StableHashingContext<'a, 'tcx>,
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 /// A wrapper for slices with the additional invariant
563 /// that the slice is interned and no other slice with
564 /// the same contents can exist in the same context.
565 /// This means we can use pointer + length for both
566 /// equality comparisons and hashing.
567 #[derive(Debug, RustcEncodable)]
568 pub struct Slice<T>([T]);
570 impl<T> PartialEq for Slice<T> {
572 fn eq(&self, other: &Slice<T>) -> bool {
573 (&self.0 as *const [T]) == (&other.0 as *const [T])
576 impl<T> Eq for Slice<T> {}
578 impl<T> Hash for Slice<T> {
579 fn hash<H: Hasher>(&self, s: &mut H) {
580 (self.as_ptr(), self.len()).hash(s)
584 impl<T> Deref for Slice<T> {
586 fn deref(&self) -> &[T] {
591 impl<'a, T> IntoIterator for &'a Slice<T> {
593 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
594 fn into_iter(self) -> Self::IntoIter {
599 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {}
602 pub fn empty<'a>() -> &'a Slice<T> {
604 mem::transmute(slice::from_raw_parts(0x1 as *const T, 0))
609 /// Upvars do not get their own node-id. Instead, we use the pair of
610 /// the original var id (that is, the root variable that is referenced
611 /// by the upvar) and the id of the closure expression.
612 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
615 pub closure_expr_id: NodeId,
618 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
619 pub enum BorrowKind {
620 /// Data must be immutable and is aliasable.
623 /// Data must be immutable but not aliasable. This kind of borrow
624 /// cannot currently be expressed by the user and is used only in
625 /// implicit closure bindings. It is needed when the closure
626 /// is borrowing or mutating a mutable referent, e.g.:
628 /// let x: &mut isize = ...;
629 /// let y = || *x += 5;
631 /// If we were to try to translate this closure into a more explicit
632 /// form, we'd encounter an error with the code as written:
634 /// struct Env { x: & &mut isize }
635 /// let x: &mut isize = ...;
636 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
637 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
639 /// This is then illegal because you cannot mutate a `&mut` found
640 /// in an aliasable location. To solve, you'd have to translate with
641 /// an `&mut` borrow:
643 /// struct Env { x: & &mut isize }
644 /// let x: &mut isize = ...;
645 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
646 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
648 /// Now the assignment to `**env.x` is legal, but creating a
649 /// mutable pointer to `x` is not because `x` is not mutable. We
650 /// could fix this by declaring `x` as `let mut x`. This is ok in
651 /// user code, if awkward, but extra weird for closures, since the
652 /// borrow is hidden.
654 /// So we introduce a "unique imm" borrow -- the referent is
655 /// immutable, but not aliasable. This solves the problem. For
656 /// simplicity, we don't give users the way to express this
657 /// borrow, it's just used when translating closures.
660 /// Data is mutable and not aliasable.
664 /// Information describing the capture of an upvar. This is computed
665 /// during `typeck`, specifically by `regionck`.
666 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
667 pub enum UpvarCapture<'tcx> {
668 /// Upvar is captured by value. This is always true when the
669 /// closure is labeled `move`, but can also be true in other cases
670 /// depending on inference.
673 /// Upvar is captured by reference.
674 ByRef(UpvarBorrow<'tcx>),
677 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
678 pub struct UpvarBorrow<'tcx> {
679 /// The kind of borrow: by-ref upvars have access to shared
680 /// immutable borrows, which are not part of the normal language
682 pub kind: BorrowKind,
684 /// Region of the resulting reference.
685 pub region: ty::Region<'tcx>,
688 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
690 #[derive(Copy, Clone)]
691 pub struct ClosureUpvar<'tcx> {
697 #[derive(Clone, Copy, PartialEq)]
698 pub enum IntVarValue {
700 UintType(ast::UintTy),
703 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
704 pub struct TypeParameterDef {
708 pub has_default: bool,
709 pub object_lifetime_default: ObjectLifetimeDefault,
711 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
712 /// on generic parameter `T`, asserts data behind the parameter
713 /// `T` won't be accessed during the parent type's `Drop` impl.
714 pub pure_wrt_drop: bool,
717 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
718 pub struct RegionParameterDef {
722 pub issue_32330: Option<ty::Issue32330>,
724 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
725 /// on generic parameter `'a`, asserts data of lifetime `'a`
726 /// won't be accessed during the parent type's `Drop` impl.
727 pub pure_wrt_drop: bool,
730 impl RegionParameterDef {
731 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
732 ty::EarlyBoundRegion {
739 pub fn to_bound_region(&self) -> ty::BoundRegion {
740 self.to_early_bound_region_data().to_bound_region()
744 impl ty::EarlyBoundRegion {
745 pub fn to_bound_region(&self) -> ty::BoundRegion {
746 ty::BoundRegion::BrNamed(self.def_id, self.name)
750 /// Information about the formal type/lifetime parameters associated
751 /// with an item or method. Analogous to hir::Generics.
752 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
753 pub struct Generics {
754 pub parent: Option<DefId>,
755 pub parent_regions: u32,
756 pub parent_types: u32,
757 pub regions: Vec<RegionParameterDef>,
758 pub types: Vec<TypeParameterDef>,
760 /// Reverse map to each `TypeParameterDef`'s `index` field, from
761 /// `def_id.index` (`def_id.krate` is the same as the item's).
762 pub type_param_to_index: BTreeMap<DefIndex, u32>,
768 pub fn parent_count(&self) -> usize {
769 self.parent_regions as usize + self.parent_types as usize
772 pub fn own_count(&self) -> usize {
773 self.regions.len() + self.types.len()
776 pub fn count(&self) -> usize {
777 self.parent_count() + self.own_count()
780 pub fn region_param(&self, param: &EarlyBoundRegion) -> &RegionParameterDef {
781 assert_eq!(self.parent_count(), 0);
782 &self.regions[param.index as usize - self.has_self as usize]
785 pub fn type_param(&self, param: &ParamTy) -> &TypeParameterDef {
786 assert_eq!(self.parent_count(), 0);
787 &self.types[param.idx as usize - self.has_self as usize - self.regions.len()]
791 /// Bounds on generics.
792 #[derive(Clone, Default)]
793 pub struct GenericPredicates<'tcx> {
794 pub parent: Option<DefId>,
795 pub predicates: Vec<Predicate<'tcx>>,
798 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
799 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
801 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
802 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
803 -> InstantiatedPredicates<'tcx> {
804 let mut instantiated = InstantiatedPredicates::empty();
805 self.instantiate_into(tcx, &mut instantiated, substs);
808 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
809 -> InstantiatedPredicates<'tcx> {
810 InstantiatedPredicates {
811 predicates: self.predicates.subst(tcx, substs)
815 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
816 instantiated: &mut InstantiatedPredicates<'tcx>,
817 substs: &Substs<'tcx>) {
818 if let Some(def_id) = self.parent {
819 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
821 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
824 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
825 -> InstantiatedPredicates<'tcx> {
826 let mut instantiated = InstantiatedPredicates::empty();
827 self.instantiate_identity_into(tcx, &mut instantiated);
831 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
832 instantiated: &mut InstantiatedPredicates<'tcx>) {
833 if let Some(def_id) = self.parent {
834 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
836 instantiated.predicates.extend(&self.predicates)
839 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
840 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
841 -> InstantiatedPredicates<'tcx>
843 assert_eq!(self.parent, None);
844 InstantiatedPredicates {
845 predicates: self.predicates.iter().map(|pred| {
846 pred.subst_supertrait(tcx, poly_trait_ref)
852 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
853 pub enum Predicate<'tcx> {
854 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
855 /// the `Self` type of the trait reference and `A`, `B`, and `C`
856 /// would be the type parameters.
857 Trait(PolyTraitPredicate<'tcx>),
859 /// where `T1 == T2`.
860 Equate(PolyEquatePredicate<'tcx>),
863 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
866 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
868 /// where <T as TraitRef>::Name == X, approximately.
869 /// See `ProjectionPredicate` struct for details.
870 Projection(PolyProjectionPredicate<'tcx>),
873 WellFormed(Ty<'tcx>),
875 /// trait must be object-safe
878 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
879 /// for some substitutions `...` and T being a closure type.
880 /// Satisfied (or refuted) once we know the closure's kind.
881 ClosureKind(DefId, ClosureKind),
884 Subtype(PolySubtypePredicate<'tcx>),
887 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
888 /// Performs a substitution suitable for going from a
889 /// poly-trait-ref to supertraits that must hold if that
890 /// poly-trait-ref holds. This is slightly different from a normal
891 /// substitution in terms of what happens with bound regions. See
892 /// lengthy comment below for details.
893 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
894 trait_ref: &ty::PolyTraitRef<'tcx>)
895 -> ty::Predicate<'tcx>
897 // The interaction between HRTB and supertraits is not entirely
898 // obvious. Let me walk you (and myself) through an example.
900 // Let's start with an easy case. Consider two traits:
902 // trait Foo<'a> : Bar<'a,'a> { }
903 // trait Bar<'b,'c> { }
905 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
906 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
907 // knew that `Foo<'x>` (for any 'x) then we also know that
908 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
909 // normal substitution.
911 // In terms of why this is sound, the idea is that whenever there
912 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
913 // holds. So if there is an impl of `T:Foo<'a>` that applies to
914 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
917 // Another example to be careful of is this:
919 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
920 // trait Bar1<'b,'c> { }
922 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
923 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
924 // reason is similar to the previous example: any impl of
925 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
926 // basically we would want to collapse the bound lifetimes from
927 // the input (`trait_ref`) and the supertraits.
929 // To achieve this in practice is fairly straightforward. Let's
930 // consider the more complicated scenario:
932 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
933 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
934 // where both `'x` and `'b` would have a DB index of 1.
935 // The substitution from the input trait-ref is therefore going to be
936 // `'a => 'x` (where `'x` has a DB index of 1).
937 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
938 // early-bound parameter and `'b' is a late-bound parameter with a
940 // - If we replace `'a` with `'x` from the input, it too will have
941 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
942 // just as we wanted.
944 // There is only one catch. If we just apply the substitution `'a
945 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
946 // adjust the DB index because we substituting into a binder (it
947 // tries to be so smart...) resulting in `for<'x> for<'b>
948 // Bar1<'x,'b>` (we have no syntax for this, so use your
949 // imagination). Basically the 'x will have DB index of 2 and 'b
950 // will have DB index of 1. Not quite what we want. So we apply
951 // the substitution to the *contents* of the trait reference,
952 // rather than the trait reference itself (put another way, the
953 // substitution code expects equal binding levels in the values
954 // from the substitution and the value being substituted into, and
955 // this trick achieves that).
957 let substs = &trait_ref.0.substs;
959 Predicate::Trait(ty::Binder(ref data)) =>
960 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
961 Predicate::Equate(ty::Binder(ref data)) =>
962 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
963 Predicate::Subtype(ty::Binder(ref data)) =>
964 Predicate::Subtype(ty::Binder(data.subst(tcx, substs))),
965 Predicate::RegionOutlives(ty::Binder(ref data)) =>
966 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
967 Predicate::TypeOutlives(ty::Binder(ref data)) =>
968 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
969 Predicate::Projection(ty::Binder(ref data)) =>
970 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
971 Predicate::WellFormed(data) =>
972 Predicate::WellFormed(data.subst(tcx, substs)),
973 Predicate::ObjectSafe(trait_def_id) =>
974 Predicate::ObjectSafe(trait_def_id),
975 Predicate::ClosureKind(closure_def_id, kind) =>
976 Predicate::ClosureKind(closure_def_id, kind),
981 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
982 pub struct TraitPredicate<'tcx> {
983 pub trait_ref: TraitRef<'tcx>
985 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
987 impl<'tcx> TraitPredicate<'tcx> {
988 pub fn def_id(&self) -> DefId {
989 self.trait_ref.def_id
992 /// Creates the dep-node for selecting/evaluating this trait reference.
993 fn dep_node(&self) -> DepNode<DefId> {
994 // Extact the trait-def and first def-id from inputs. See the
995 // docs for `DepNode::TraitSelect` for more information.
996 let trait_def_id = self.def_id();
999 .flat_map(|t| t.walk())
1000 .filter_map(|t| match t.sty {
1001 ty::TyAdt(adt_def, _) => Some(adt_def.did),
1005 .unwrap_or(trait_def_id);
1006 DepNode::TraitSelect {
1007 trait_def_id: trait_def_id,
1008 input_def_id: input_def_id
1012 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
1013 self.trait_ref.input_types()
1016 pub fn self_ty(&self) -> Ty<'tcx> {
1017 self.trait_ref.self_ty()
1021 impl<'tcx> PolyTraitPredicate<'tcx> {
1022 pub fn def_id(&self) -> DefId {
1023 // ok to skip binder since trait def-id does not care about regions
1027 pub fn dep_node(&self) -> DepNode<DefId> {
1028 // ok to skip binder since depnode does not care about regions
1033 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1034 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
1035 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
1037 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1038 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
1039 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1040 pub type PolyRegionOutlivesPredicate<'tcx> = PolyOutlivesPredicate<ty::Region<'tcx>,
1042 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
1044 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1045 pub struct SubtypePredicate<'tcx> {
1046 pub a_is_expected: bool,
1050 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1052 /// This kind of predicate has no *direct* correspondent in the
1053 /// syntax, but it roughly corresponds to the syntactic forms:
1055 /// 1. `T : TraitRef<..., Item=Type>`
1056 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1058 /// In particular, form #1 is "desugared" to the combination of a
1059 /// normal trait predicate (`T : TraitRef<...>`) and one of these
1060 /// predicates. Form #2 is a broader form in that it also permits
1061 /// equality between arbitrary types. Processing an instance of Form
1062 /// #2 eventually yields one of these `ProjectionPredicate`
1063 /// instances to normalize the LHS.
1064 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1065 pub struct ProjectionPredicate<'tcx> {
1066 pub projection_ty: ProjectionTy<'tcx>,
1070 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1072 impl<'tcx> PolyProjectionPredicate<'tcx> {
1073 pub fn item_name(&self) -> Name {
1074 self.0.projection_ty.item_name // safe to skip the binder to access a name
1078 pub trait ToPolyTraitRef<'tcx> {
1079 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1082 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1083 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1084 assert!(!self.has_escaping_regions());
1085 ty::Binder(self.clone())
1089 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1090 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1091 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1095 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
1096 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1097 // Note: unlike with TraitRef::to_poly_trait_ref(),
1098 // self.0.trait_ref is permitted to have escaping regions.
1099 // This is because here `self` has a `Binder` and so does our
1100 // return value, so we are preserving the number of binding
1102 ty::Binder(self.0.projection_ty.trait_ref)
1106 pub trait ToPredicate<'tcx> {
1107 fn to_predicate(&self) -> Predicate<'tcx>;
1110 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1111 fn to_predicate(&self) -> Predicate<'tcx> {
1112 // we're about to add a binder, so let's check that we don't
1113 // accidentally capture anything, or else that might be some
1114 // weird debruijn accounting.
1115 assert!(!self.has_escaping_regions());
1117 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
1118 trait_ref: self.clone()
1123 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1124 fn to_predicate(&self) -> Predicate<'tcx> {
1125 ty::Predicate::Trait(self.to_poly_trait_predicate())
1129 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
1130 fn to_predicate(&self) -> Predicate<'tcx> {
1131 Predicate::Equate(self.clone())
1135 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1136 fn to_predicate(&self) -> Predicate<'tcx> {
1137 Predicate::RegionOutlives(self.clone())
1141 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1142 fn to_predicate(&self) -> Predicate<'tcx> {
1143 Predicate::TypeOutlives(self.clone())
1147 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1148 fn to_predicate(&self) -> Predicate<'tcx> {
1149 Predicate::Projection(self.clone())
1153 impl<'tcx> Predicate<'tcx> {
1154 /// Iterates over the types in this predicate. Note that in all
1155 /// cases this is skipping over a binder, so late-bound regions
1156 /// with depth 0 are bound by the predicate.
1157 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1158 let vec: Vec<_> = match *self {
1159 ty::Predicate::Trait(ref data) => {
1160 data.skip_binder().input_types().collect()
1162 ty::Predicate::Equate(ty::Binder(ref data)) => {
1163 vec![data.0, data.1]
1165 ty::Predicate::Subtype(ty::Binder(SubtypePredicate { a, b, a_is_expected: _ })) => {
1168 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
1171 ty::Predicate::RegionOutlives(..) => {
1174 ty::Predicate::Projection(ref data) => {
1175 let trait_inputs = data.0.projection_ty.trait_ref.input_types();
1176 trait_inputs.chain(Some(data.0.ty)).collect()
1178 ty::Predicate::WellFormed(data) => {
1181 ty::Predicate::ObjectSafe(_trait_def_id) => {
1184 ty::Predicate::ClosureKind(_closure_def_id, _kind) => {
1189 // The only reason to collect into a vector here is that I was
1190 // too lazy to make the full (somewhat complicated) iterator
1191 // type that would be needed here. But I wanted this fn to
1192 // return an iterator conceptually, rather than a `Vec`, so as
1193 // to be closer to `Ty::walk`.
1197 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1199 Predicate::Trait(ref t) => {
1200 Some(t.to_poly_trait_ref())
1202 Predicate::Projection(..) |
1203 Predicate::Equate(..) |
1204 Predicate::Subtype(..) |
1205 Predicate::RegionOutlives(..) |
1206 Predicate::WellFormed(..) |
1207 Predicate::ObjectSafe(..) |
1208 Predicate::ClosureKind(..) |
1209 Predicate::TypeOutlives(..) => {
1216 /// Represents the bounds declared on a particular set of type
1217 /// parameters. Should eventually be generalized into a flag list of
1218 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1219 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1220 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1221 /// the `GenericPredicates` are expressed in terms of the bound type
1222 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1223 /// represented a set of bounds for some particular instantiation,
1224 /// meaning that the generic parameters have been substituted with
1229 /// struct Foo<T,U:Bar<T>> { ... }
1231 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1232 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1233 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1234 /// [usize:Bar<isize>]]`.
1236 pub struct InstantiatedPredicates<'tcx> {
1237 pub predicates: Vec<Predicate<'tcx>>,
1240 impl<'tcx> InstantiatedPredicates<'tcx> {
1241 pub fn empty() -> InstantiatedPredicates<'tcx> {
1242 InstantiatedPredicates { predicates: vec![] }
1245 pub fn is_empty(&self) -> bool {
1246 self.predicates.is_empty()
1250 /// When type checking, we use the `ParameterEnvironment` to track
1251 /// details about the set of where-clauses that are in scope at this
1252 /// particular point.
1253 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1254 pub struct ParameterEnvironment<'tcx> {
1255 /// Obligations that the caller must satisfy. This is basically
1256 /// the set of bounds on the in-scope type parameters, translated
1257 /// into Obligations, and elaborated and normalized.
1258 pub caller_bounds: &'tcx Slice<ty::Predicate<'tcx>>,
1261 impl<'tcx> ParameterEnvironment<'tcx> {
1262 pub fn and<T>(self, value: T) -> ParameterEnvironmentAnd<'tcx, T> {
1263 ParameterEnvironmentAnd {
1270 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1271 pub struct ParameterEnvironmentAnd<'tcx, T> {
1272 pub param_env: ParameterEnvironment<'tcx>,
1276 impl<'tcx, T> ParameterEnvironmentAnd<'tcx, T> {
1277 pub fn into_parts(self) -> (ParameterEnvironment<'tcx>, T) {
1278 (self.param_env, self.value)
1282 #[derive(Copy, Clone, Debug)]
1283 pub struct Destructor {
1284 /// The def-id of the destructor method
1289 flags AdtFlags: u32 {
1290 const NO_ADT_FLAGS = 0,
1291 const IS_ENUM = 1 << 0,
1292 const IS_PHANTOM_DATA = 1 << 1,
1293 const IS_FUNDAMENTAL = 1 << 2,
1294 const IS_UNION = 1 << 3,
1295 const IS_BOX = 1 << 4,
1300 pub struct VariantDef {
1301 /// The variant's DefId. If this is a tuple-like struct,
1302 /// this is the DefId of the struct's ctor.
1304 pub name: Name, // struct's name if this is a struct
1305 pub discr: VariantDiscr,
1306 pub fields: Vec<FieldDef>,
1307 pub ctor_kind: CtorKind,
1310 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1311 pub enum VariantDiscr {
1312 /// Explicit value for this variant, i.e. `X = 123`.
1313 /// The `DefId` corresponds to the embedded constant.
1316 /// The previous variant's discriminant plus one.
1317 /// For efficiency reasons, the distance from the
1318 /// last `Explicit` discriminant is being stored,
1319 /// or `0` for the first variant, if it has none.
1324 pub struct FieldDef {
1327 pub vis: Visibility,
1330 /// The definition of an abstract data type - a struct or enum.
1332 /// These are all interned (by intern_adt_def) into the adt_defs
1336 pub variants: Vec<VariantDef>,
1338 pub repr: ReprOptions,
1341 impl PartialEq for AdtDef {
1342 // AdtDef are always interned and this is part of TyS equality
1344 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1347 impl Eq for AdtDef {}
1349 impl Hash for AdtDef {
1351 fn hash<H: Hasher>(&self, s: &mut H) {
1352 (self as *const AdtDef).hash(s)
1356 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1357 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1362 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1365 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for AdtDef {
1366 fn hash_stable<W: StableHasherResult>(&self,
1367 hcx: &mut StableHashingContext<'a, 'tcx>,
1368 hasher: &mut StableHasher<W>) {
1376 did.hash_stable(hcx, hasher);
1377 variants.hash_stable(hcx, hasher);
1378 flags.hash_stable(hcx, hasher);
1379 repr.hash_stable(hcx, hasher);
1383 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1384 pub enum AdtKind { Struct, Union, Enum }
1387 #[derive(RustcEncodable, RustcDecodable, Default)]
1388 flags ReprFlags: u8 {
1389 const IS_C = 1 << 0,
1390 const IS_PACKED = 1 << 1,
1391 const IS_SIMD = 1 << 2,
1392 // Internal only for now. If true, don't reorder fields.
1393 const IS_LINEAR = 1 << 3,
1395 // Any of these flags being set prevent field reordering optimisation.
1396 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1397 ReprFlags::IS_PACKED.bits |
1398 ReprFlags::IS_SIMD.bits |
1399 ReprFlags::IS_LINEAR.bits,
1403 impl_stable_hash_for!(struct ReprFlags {
1409 /// Represents the repr options provided by the user,
1410 #[derive(Copy, Clone, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1411 pub struct ReprOptions {
1412 pub int: Option<attr::IntType>,
1414 pub flags: ReprFlags,
1417 impl_stable_hash_for!(struct ReprOptions {
1424 pub fn new(tcx: TyCtxt, did: DefId) -> ReprOptions {
1425 let mut flags = ReprFlags::empty();
1426 let mut size = None;
1427 let mut max_align = 0;
1428 for attr in tcx.get_attrs(did).iter() {
1429 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1430 flags.insert(match r {
1431 attr::ReprExtern => ReprFlags::IS_C,
1432 attr::ReprPacked => ReprFlags::IS_PACKED,
1433 attr::ReprSimd => ReprFlags::IS_SIMD,
1434 attr::ReprInt(i) => {
1438 attr::ReprAlign(align) => {
1439 max_align = cmp::max(align, max_align);
1446 // FIXME(eddyb) This is deprecated and should be removed.
1447 if tcx.has_attr(did, "simd") {
1448 flags.insert(ReprFlags::IS_SIMD);
1451 // This is here instead of layout because the choice must make it into metadata.
1452 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1453 flags.insert(ReprFlags::IS_LINEAR);
1455 ReprOptions { int: size, align: max_align, flags: flags }
1459 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1461 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1463 pub fn packed(&self) -> bool { self.flags.contains(ReprFlags::IS_PACKED) }
1465 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1467 pub fn discr_type(&self) -> attr::IntType {
1468 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Is))
1471 /// Returns true if this `#[repr()]` should inhabit "smart enum
1472 /// layout" optimizations, such as representing `Foo<&T>` as a
1474 pub fn inhibit_enum_layout_opt(&self) -> bool {
1475 self.c() || self.int.is_some()
1479 impl<'a, 'gcx, 'tcx> AdtDef {
1483 variants: Vec<VariantDef>,
1484 repr: ReprOptions) -> Self {
1485 let mut flags = AdtFlags::NO_ADT_FLAGS;
1486 let attrs = tcx.get_attrs(did);
1487 if attr::contains_name(&attrs, "fundamental") {
1488 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1490 if Some(did) == tcx.lang_items.phantom_data() {
1491 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1493 if Some(did) == tcx.lang_items.owned_box() {
1494 flags = flags | AdtFlags::IS_BOX;
1497 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
1498 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
1499 AdtKind::Struct => {}
1510 pub fn is_struct(&self) -> bool {
1511 !self.is_union() && !self.is_enum()
1515 pub fn is_union(&self) -> bool {
1516 self.flags.intersects(AdtFlags::IS_UNION)
1520 pub fn is_enum(&self) -> bool {
1521 self.flags.intersects(AdtFlags::IS_ENUM)
1524 /// Returns the kind of the ADT - Struct or Enum.
1526 pub fn adt_kind(&self) -> AdtKind {
1529 } else if self.is_union() {
1536 pub fn descr(&self) -> &'static str {
1537 match self.adt_kind() {
1538 AdtKind::Struct => "struct",
1539 AdtKind::Union => "union",
1540 AdtKind::Enum => "enum",
1544 pub fn variant_descr(&self) -> &'static str {
1545 match self.adt_kind() {
1546 AdtKind::Struct => "struct",
1547 AdtKind::Union => "union",
1548 AdtKind::Enum => "variant",
1552 /// Returns whether this type is #[fundamental] for the purposes
1553 /// of coherence checking.
1555 pub fn is_fundamental(&self) -> bool {
1556 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
1559 /// Returns true if this is PhantomData<T>.
1561 pub fn is_phantom_data(&self) -> bool {
1562 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
1565 /// Returns true if this is Box<T>.
1567 pub fn is_box(&self) -> bool {
1568 self.flags.intersects(AdtFlags::IS_BOX)
1571 /// Returns whether this type has a destructor.
1572 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
1573 self.destructor(tcx).is_some()
1576 /// Asserts this is a struct and returns the struct's unique
1578 pub fn struct_variant(&self) -> &VariantDef {
1579 assert!(!self.is_enum());
1584 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
1585 tcx.predicates_of(self.did)
1588 /// Returns an iterator over all fields contained
1591 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
1592 self.variants.iter().flat_map(|v| v.fields.iter())
1596 pub fn is_univariant(&self) -> bool {
1597 self.variants.len() == 1
1600 pub fn is_payloadfree(&self) -> bool {
1601 !self.variants.is_empty() &&
1602 self.variants.iter().all(|v| v.fields.is_empty())
1605 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
1608 .find(|v| v.did == vid)
1609 .expect("variant_with_id: unknown variant")
1612 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1615 .position(|v| v.did == vid)
1616 .expect("variant_index_with_id: unknown variant")
1619 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
1621 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
1622 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
1623 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.struct_variant(),
1624 _ => bug!("unexpected def {:?} in variant_of_def", def)
1629 pub fn discriminants(&'a self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1630 -> impl Iterator<Item=ConstInt> + 'a {
1631 let repr_type = self.repr.discr_type();
1632 let initial = repr_type.initial_discriminant(tcx.global_tcx());
1633 let mut prev_discr = None::<ConstInt>;
1634 self.variants.iter().map(move |v| {
1635 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr());
1636 if let VariantDiscr::Explicit(expr_did) = v.discr {
1637 let substs = Substs::empty();
1638 match tcx.const_eval((expr_did, substs)) {
1639 Ok(ConstVal::Integral(v)) => {
1643 if !expr_did.is_local() {
1644 span_bug!(tcx.def_span(expr_did),
1645 "variant discriminant evaluation succeeded \
1646 in its crate but failed locally: {:?}", err);
1651 prev_discr = Some(discr);
1657 /// Compute the discriminant value used by a specific variant.
1658 /// Unlike `discriminants`, this is (amortized) constant-time,
1659 /// only doing at most one query for evaluating an explicit
1660 /// discriminant (the last one before the requested variant),
1661 /// assuming there are no constant-evaluation errors there.
1662 pub fn discriminant_for_variant(&self,
1663 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1664 variant_index: usize)
1666 let repr_type = self.repr.discr_type();
1667 let mut explicit_value = repr_type.initial_discriminant(tcx.global_tcx());
1668 let mut explicit_index = variant_index;
1670 match self.variants[explicit_index].discr {
1671 ty::VariantDiscr::Relative(0) => break,
1672 ty::VariantDiscr::Relative(distance) => {
1673 explicit_index -= distance;
1675 ty::VariantDiscr::Explicit(expr_did) => {
1676 let substs = Substs::empty();
1677 match tcx.const_eval((expr_did, substs)) {
1678 Ok(ConstVal::Integral(v)) => {
1683 if !expr_did.is_local() {
1684 span_bug!(tcx.def_span(expr_did),
1685 "variant discriminant evaluation succeeded \
1686 in its crate but failed locally: {:?}", err);
1688 if explicit_index == 0 {
1691 explicit_index -= 1;
1697 let discr = explicit_value.to_u128_unchecked()
1698 .wrapping_add((variant_index - explicit_index) as u128);
1700 attr::UnsignedInt(ty) => {
1701 ConstInt::new_unsigned_truncating(discr, ty,
1702 tcx.sess.target.uint_type)
1704 attr::SignedInt(ty) => {
1705 ConstInt::new_signed_truncating(discr as i128, ty,
1706 tcx.sess.target.int_type)
1711 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
1712 tcx.adt_destructor(self.did)
1715 /// Returns a list of types such that `Self: Sized` if and only
1716 /// if that type is Sized, or `TyErr` if this type is recursive.
1718 /// Oddly enough, checking that the sized-constraint is Sized is
1719 /// actually more expressive than checking all members:
1720 /// the Sized trait is inductive, so an associated type that references
1721 /// Self would prevent its containing ADT from being Sized.
1723 /// Due to normalization being eager, this applies even if
1724 /// the associated type is behind a pointer, e.g. issue #31299.
1725 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
1726 match queries::adt_sized_constraint::try_get(tcx, DUMMY_SP, self.did) {
1729 debug!("adt_sized_constraint: {:?} is recursive", self);
1730 // This should be reported as an error by `check_representable`.
1732 // Consider the type as Sized in the meanwhile to avoid
1734 tcx.intern_type_list(&[tcx.types.err])
1739 fn sized_constraint_for_ty(&self,
1740 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1743 let result = match ty.sty {
1744 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
1745 TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
1746 TyArray(..) | TyClosure(..) | TyNever => {
1750 TyStr | TyDynamic(..) | TySlice(_) | TyError => {
1751 // these are never sized - return the target type
1755 TyTuple(ref tys, _) => {
1758 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
1762 TyAdt(adt, substs) => {
1764 let adt_tys = adt.sized_constraint(tcx);
1765 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
1768 .map(|ty| ty.subst(tcx, substs))
1769 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
1773 TyProjection(..) | TyAnon(..) => {
1774 // must calculate explicitly.
1775 // FIXME: consider special-casing always-Sized projections
1780 // perf hack: if there is a `T: Sized` bound, then
1781 // we know that `T` is Sized and do not need to check
1784 let sized_trait = match tcx.lang_items.sized_trait() {
1786 _ => return vec![ty]
1788 let sized_predicate = Binder(TraitRef {
1789 def_id: sized_trait,
1790 substs: tcx.mk_substs_trait(ty, &[])
1792 let predicates = tcx.predicates_of(self.did).predicates;
1793 if predicates.into_iter().any(|p| p == sized_predicate) {
1801 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
1805 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
1810 impl<'a, 'gcx, 'tcx> VariantDef {
1812 pub fn find_field_named(&self,
1814 -> Option<&FieldDef> {
1815 self.fields.iter().find(|f| f.name == name)
1819 pub fn index_of_field_named(&self,
1822 self.fields.iter().position(|f| f.name == name)
1826 pub fn field_named(&self, name: ast::Name) -> &FieldDef {
1827 self.find_field_named(name).unwrap()
1831 impl<'a, 'gcx, 'tcx> FieldDef {
1832 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1833 tcx.type_of(self.did).subst(tcx, subst)
1837 /// Records the substitutions used to translate the polytype for an
1838 /// item into the monotype of an item reference.
1839 #[derive(Clone, RustcEncodable, RustcDecodable)]
1840 pub struct ItemSubsts<'tcx> {
1841 pub substs: &'tcx Substs<'tcx>,
1844 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1845 pub enum ClosureKind {
1846 // Warning: Ordering is significant here! The ordering is chosen
1847 // because the trait Fn is a subtrait of FnMut and so in turn, and
1848 // hence we order it so that Fn < FnMut < FnOnce.
1854 impl<'a, 'tcx> ClosureKind {
1855 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
1857 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
1858 ClosureKind::FnMut => {
1859 tcx.require_lang_item(FnMutTraitLangItem)
1861 ClosureKind::FnOnce => {
1862 tcx.require_lang_item(FnOnceTraitLangItem)
1867 /// True if this a type that impls this closure kind
1868 /// must also implement `other`.
1869 pub fn extends(self, other: ty::ClosureKind) -> bool {
1870 match (self, other) {
1871 (ClosureKind::Fn, ClosureKind::Fn) => true,
1872 (ClosureKind::Fn, ClosureKind::FnMut) => true,
1873 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
1874 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
1875 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
1876 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
1882 impl<'tcx> TyS<'tcx> {
1883 /// Iterator that walks `self` and any types reachable from
1884 /// `self`, in depth-first order. Note that just walks the types
1885 /// that appear in `self`, it does not descend into the fields of
1886 /// structs or variants. For example:
1889 /// isize => { isize }
1890 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
1891 /// [isize] => { [isize], isize }
1893 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
1894 TypeWalker::new(self)
1897 /// Iterator that walks the immediate children of `self`. Hence
1898 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
1899 /// (but not `i32`, like `walk`).
1900 pub fn walk_shallow(&'tcx self) -> AccIntoIter<walk::TypeWalkerArray<'tcx>> {
1901 walk::walk_shallow(self)
1904 /// Walks `ty` and any types appearing within `ty`, invoking the
1905 /// callback `f` on each type. If the callback returns false, then the
1906 /// children of the current type are ignored.
1908 /// Note: prefer `ty.walk()` where possible.
1909 pub fn maybe_walk<F>(&'tcx self, mut f: F)
1910 where F : FnMut(Ty<'tcx>) -> bool
1912 let mut walker = self.walk();
1913 while let Some(ty) = walker.next() {
1915 walker.skip_current_subtree();
1921 impl<'tcx> ItemSubsts<'tcx> {
1922 pub fn is_noop(&self) -> bool {
1923 self.substs.is_noop()
1927 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1928 pub enum LvaluePreference {
1933 impl LvaluePreference {
1934 pub fn from_mutbl(m: hir::Mutability) -> Self {
1936 hir::MutMutable => PreferMutLvalue,
1937 hir::MutImmutable => NoPreference,
1943 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
1945 hir::MutMutable => MutBorrow,
1946 hir::MutImmutable => ImmBorrow,
1950 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
1951 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
1952 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
1954 pub fn to_mutbl_lossy(self) -> hir::Mutability {
1956 MutBorrow => hir::MutMutable,
1957 ImmBorrow => hir::MutImmutable,
1959 // We have no type corresponding to a unique imm borrow, so
1960 // use `&mut`. It gives all the capabilities of an `&uniq`
1961 // and hence is a safe "over approximation".
1962 UniqueImmBorrow => hir::MutMutable,
1966 pub fn to_user_str(&self) -> &'static str {
1968 MutBorrow => "mutable",
1969 ImmBorrow => "immutable",
1970 UniqueImmBorrow => "uniquely immutable",
1975 #[derive(Debug, Clone)]
1976 pub enum Attributes<'gcx> {
1977 Owned(Rc<[ast::Attribute]>),
1978 Borrowed(&'gcx [ast::Attribute])
1981 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
1982 type Target = [ast::Attribute];
1984 fn deref(&self) -> &[ast::Attribute] {
1986 &Attributes::Owned(ref data) => &data,
1987 &Attributes::Borrowed(data) => data
1992 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
1993 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
1994 self.typeck_tables_of(self.hir.body_owner_def_id(body))
1997 /// Returns an iterator of the def-ids for all body-owners in this
1998 /// crate. If you would prefer to iterate over the bodies
1999 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
2000 pub fn body_owners(self) -> impl Iterator<Item = DefId> + 'a {
2004 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
2007 pub fn expr_span(self, id: NodeId) -> Span {
2008 match self.hir.find(id) {
2009 Some(hir_map::NodeExpr(e)) => {
2013 bug!("Node id {} is not an expr: {:?}", id, f);
2016 bug!("Node id {} is not present in the node map", id);
2021 pub fn local_var_name_str(self, id: NodeId) -> InternedString {
2022 match self.hir.find(id) {
2023 Some(hir_map::NodeLocal(pat)) => {
2025 hir::PatKind::Binding(_, _, ref path1, _) => path1.node.as_str(),
2027 bug!("Variable id {} maps to {:?}, not local", id, pat);
2031 r => bug!("Variable id {} maps to {:?}, not local", id, r),
2035 pub fn expr_is_lval(self, expr: &hir::Expr) -> bool {
2037 hir::ExprPath(hir::QPath::Resolved(_, ref path)) => {
2039 Def::Local(..) | Def::Upvar(..) | Def::Static(..) | Def::Err => true,
2044 hir::ExprType(ref e, _) => {
2045 self.expr_is_lval(e)
2048 hir::ExprUnary(hir::UnDeref, _) |
2049 hir::ExprField(..) |
2050 hir::ExprTupField(..) |
2051 hir::ExprIndex(..) => {
2055 // Partially qualified paths in expressions can only legally
2056 // refer to associated items which are always rvalues.
2057 hir::ExprPath(hir::QPath::TypeRelative(..)) |
2060 hir::ExprMethodCall(..) |
2061 hir::ExprStruct(..) |
2064 hir::ExprMatch(..) |
2065 hir::ExprClosure(..) |
2066 hir::ExprBlock(..) |
2067 hir::ExprRepeat(..) |
2068 hir::ExprArray(..) |
2069 hir::ExprBreak(..) |
2070 hir::ExprAgain(..) |
2072 hir::ExprWhile(..) |
2074 hir::ExprAssign(..) |
2075 hir::ExprInlineAsm(..) |
2076 hir::ExprAssignOp(..) |
2078 hir::ExprUnary(..) |
2080 hir::ExprAddrOf(..) |
2081 hir::ExprBinary(..) |
2082 hir::ExprCast(..) => {
2088 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2089 self.associated_items(id)
2090 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2094 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2095 self.associated_items(did).any(|item| {
2096 item.relevant_for_never()
2100 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2101 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2102 match self.hir.get(node_id) {
2103 hir_map::NodeTraitItem(_) | hir_map::NodeImplItem(_) => true,
2107 match self.describe_def(def_id).expect("no def for def-id") {
2108 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2113 if is_associated_item {
2114 Some(self.associated_item(def_id))
2120 fn associated_item_from_trait_item_ref(self,
2121 parent_def_id: DefId,
2122 parent_vis: &hir::Visibility,
2123 trait_item_ref: &hir::TraitItemRef)
2125 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2126 let (kind, has_self) = match trait_item_ref.kind {
2127 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2128 hir::AssociatedItemKind::Method { has_self } => {
2129 (ty::AssociatedKind::Method, has_self)
2131 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2135 name: trait_item_ref.name,
2137 // Visibility of trait items is inherited from their traits.
2138 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2139 defaultness: trait_item_ref.defaultness,
2141 container: TraitContainer(parent_def_id),
2142 method_has_self_argument: has_self
2146 fn associated_item_from_impl_item_ref(self,
2147 parent_def_id: DefId,
2148 impl_item_ref: &hir::ImplItemRef)
2150 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2151 let (kind, has_self) = match impl_item_ref.kind {
2152 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2153 hir::AssociatedItemKind::Method { has_self } => {
2154 (ty::AssociatedKind::Method, has_self)
2156 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2159 ty::AssociatedItem {
2160 name: impl_item_ref.name,
2162 // Visibility of trait impl items doesn't matter.
2163 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2164 defaultness: impl_item_ref.defaultness,
2166 container: ImplContainer(parent_def_id),
2167 method_has_self_argument: has_self
2171 #[inline] // FIXME(#35870) Avoid closures being unexported due to impl Trait.
2172 pub fn associated_items(self, def_id: DefId)
2173 -> impl Iterator<Item = ty::AssociatedItem> + 'a {
2174 let def_ids = self.associated_item_def_ids(def_id);
2175 (0..def_ids.len()).map(move |i| self.associated_item(def_ids[i]))
2178 /// Returns true if the impls are the same polarity and are implementing
2179 /// a trait which contains no items
2180 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2181 if !self.sess.features.borrow().overlapping_marker_traits {
2184 let trait1_is_empty = self.impl_trait_ref(def_id1)
2185 .map_or(false, |trait_ref| {
2186 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2188 let trait2_is_empty = self.impl_trait_ref(def_id2)
2189 .map_or(false, |trait_ref| {
2190 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2192 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2197 // Returns `ty::VariantDef` if `def` refers to a struct,
2198 // or variant or their constructors, panics otherwise.
2199 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2201 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2202 let enum_did = self.parent_def_id(did).unwrap();
2203 self.adt_def(enum_did).variant_with_id(did)
2205 Def::Struct(did) | Def::Union(did) => {
2206 self.adt_def(did).struct_variant()
2208 Def::StructCtor(ctor_did, ..) => {
2209 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2210 self.adt_def(did).struct_variant()
2212 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2216 pub fn def_key(self, id: DefId) -> hir_map::DefKey {
2218 self.hir.def_key(id)
2220 self.sess.cstore.def_key(id)
2224 /// Convert a `DefId` into its fully expanded `DefPath` (every
2225 /// `DefId` is really just an interned def-path).
2227 /// Note that if `id` is not local to this crate, the result will
2228 /// be a non-local `DefPath`.
2229 pub fn def_path(self, id: DefId) -> hir_map::DefPath {
2231 self.hir.def_path(id)
2233 self.sess.cstore.def_path(id)
2238 pub fn def_path_hash(self, def_id: DefId) -> ich::Fingerprint {
2239 if def_id.is_local() {
2240 self.hir.definitions().def_path_hash(def_id.index)
2242 self.sess.cstore.def_path_hash(def_id)
2246 pub fn vis_is_accessible_from(self, vis: Visibility, block: NodeId) -> bool {
2247 vis.is_accessible_from(self.hir.local_def_id(self.hir.get_module_parent(block)), self)
2250 pub fn item_name(self, id: DefId) -> ast::Name {
2251 if let Some(id) = self.hir.as_local_node_id(id) {
2253 } else if id.index == CRATE_DEF_INDEX {
2254 self.sess.cstore.original_crate_name(id.krate)
2256 let def_key = self.sess.cstore.def_key(id);
2257 // The name of a StructCtor is that of its struct parent.
2258 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2259 self.item_name(DefId {
2261 index: def_key.parent.unwrap()
2264 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2265 bug!("item_name: no name for {:?}", self.def_path(id));
2271 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2272 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2276 ty::InstanceDef::Item(did) => {
2277 self.optimized_mir(did)
2279 ty::InstanceDef::Intrinsic(..) |
2280 ty::InstanceDef::FnPtrShim(..) |
2281 ty::InstanceDef::Virtual(..) |
2282 ty::InstanceDef::ClosureOnceShim { .. } |
2283 ty::InstanceDef::DropGlue(..) => {
2284 self.mir_shims(instance)
2289 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2290 /// Returns None if there is no MIR for the DefId
2291 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2292 if self.is_mir_available(did) {
2293 Some(self.optimized_mir(did))
2299 /// Get the attributes of a definition.
2300 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2301 if let Some(id) = self.hir.as_local_node_id(did) {
2302 Attributes::Borrowed(self.hir.attrs(id))
2304 Attributes::Owned(self.item_attrs(did))
2308 /// Determine whether an item is annotated with an attribute
2309 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2310 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2313 pub fn trait_has_default_impl(self, trait_def_id: DefId) -> bool {
2314 self.trait_def(trait_def_id).has_default_impl
2317 /// Given the def_id of an impl, return the def_id of the trait it implements.
2318 /// If it implements no trait, return `None`.
2319 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2320 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2323 /// If the given def ID describes a method belonging to an impl, return the
2324 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2325 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2326 let item = if def_id.krate != LOCAL_CRATE {
2327 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2328 Some(self.associated_item(def_id))
2333 self.opt_associated_item(def_id)
2337 Some(trait_item) => {
2338 match trait_item.container {
2339 TraitContainer(_) => None,
2340 ImplContainer(def_id) => Some(def_id),
2347 pub fn node_scope_region(self, id: NodeId) -> Region<'tcx> {
2348 self.mk_region(ty::ReScope(CodeExtent::Misc(id)))
2351 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2352 /// with the name of the crate containing the impl.
2353 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2354 if impl_did.is_local() {
2355 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2356 Ok(self.hir.span(node_id))
2358 Err(self.sess.cstore.crate_name(impl_did.krate))
2363 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2364 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2365 F: FnOnce(&[hir::Freevar]) -> T,
2367 match self.freevars.borrow().get(&fid) {
2369 Some(d) => f(&d[..])
2374 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
2377 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2378 let parent_id = tcx.hir.get_parent(id);
2379 let parent_def_id = tcx.hir.local_def_id(parent_id);
2380 let parent_item = tcx.hir.expect_item(parent_id);
2381 match parent_item.node {
2382 hir::ItemImpl(.., ref impl_item_refs) => {
2383 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2384 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2386 debug_assert_eq!(assoc_item.def_id, def_id);
2391 hir::ItemTrait(.., ref trait_item_refs) => {
2392 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2393 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2396 debug_assert_eq!(assoc_item.def_id, def_id);
2404 span_bug!(parent_item.span,
2405 "unexpected parent of trait or impl item or item not found: {:?}",
2409 /// Calculates the Sized-constraint.
2411 /// In fact, there are only a few options for the types in the constraint:
2412 /// - an obviously-unsized type
2413 /// - a type parameter or projection whose Sizedness can't be known
2414 /// - a tuple of type parameters or projections, if there are multiple
2416 /// - a TyError, if a type contained itself. The representability
2417 /// check should catch this case.
2418 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2420 -> &'tcx [Ty<'tcx>] {
2421 let def = tcx.adt_def(def_id);
2423 let result = tcx.intern_type_list(&def.variants.iter().flat_map(|v| {
2426 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2427 }).collect::<Vec<_>>());
2429 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2434 /// Calculates the dtorck constraint for a type.
2435 fn adt_dtorck_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2437 -> DtorckConstraint<'tcx> {
2438 let def = tcx.adt_def(def_id);
2439 let span = tcx.def_span(def_id);
2440 debug!("dtorck_constraint: {:?}", def);
2442 if def.is_phantom_data() {
2443 let result = DtorckConstraint {
2446 tcx.mk_param_from_def(&tcx.generics_of(def_id).types[0])
2449 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2453 let mut result = def.all_fields()
2454 .map(|field| tcx.type_of(field.did))
2455 .map(|fty| tcx.dtorck_constraint_for_ty(span, fty, 0, fty))
2456 .collect::<Result<DtorckConstraint, ErrorReported>>()
2457 .unwrap_or(DtorckConstraint::empty());
2458 result.outlives.extend(tcx.destructor_constraints(def));
2461 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2466 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2469 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2470 let item = tcx.hir.expect_item(id);
2471 let vec: Vec<_> = match item.node {
2472 hir::ItemTrait(.., ref trait_item_refs) => {
2473 trait_item_refs.iter()
2474 .map(|trait_item_ref| trait_item_ref.id)
2475 .map(|id| tcx.hir.local_def_id(id.node_id))
2478 hir::ItemImpl(.., ref impl_item_refs) => {
2479 impl_item_refs.iter()
2480 .map(|impl_item_ref| impl_item_ref.id)
2481 .map(|id| tcx.hir.local_def_id(id.node_id))
2484 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2489 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
2490 tcx.hir.span_if_local(def_id).unwrap()
2493 /// If the given def ID describes an item belonging to a trait,
2494 /// return the ID of the trait that the trait item belongs to.
2495 /// Otherwise, return `None`.
2496 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
2497 tcx.opt_associated_item(def_id)
2498 .and_then(|associated_item| {
2499 match associated_item.container {
2500 TraitContainer(def_id) => Some(def_id),
2501 ImplContainer(_) => None
2506 /// See `ParameterEnvironment` struct def'n for details.
2507 fn parameter_environment<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2509 -> ParameterEnvironment<'tcx> {
2510 // Compute the bounds on Self and the type parameters.
2512 let bounds = tcx.predicates_of(def_id).instantiate_identity(tcx);
2513 let predicates = bounds.predicates;
2515 // Finally, we have to normalize the bounds in the environment, in
2516 // case they contain any associated type projections. This process
2517 // can yield errors if the put in illegal associated types, like
2518 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2519 // report these errors right here; this doesn't actually feel
2520 // right to me, because constructing the environment feels like a
2521 // kind of a "idempotent" action, but I'm not sure where would be
2522 // a better place. In practice, we construct environments for
2523 // every fn once during type checking, and we'll abort if there
2524 // are any errors at that point, so after type checking you can be
2525 // sure that this will succeed without errors anyway.
2527 let unnormalized_env = ty::ParameterEnvironment::new(tcx.intern_predicates(&predicates));
2529 let body_id = tcx.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
2530 tcx.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_id)
2532 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
2533 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
2536 pub fn provide(providers: &mut ty::maps::Providers) {
2537 util::provide(providers);
2538 *providers = ty::maps::Providers {
2540 associated_item_def_ids,
2541 adt_sized_constraint,
2542 adt_dtorck_constraint,
2544 parameter_environment,
2546 trait_impls_of: trait_def::trait_impls_of_provider,
2547 relevant_trait_impls_for: trait_def::relevant_trait_impls_provider,
2552 pub fn provide_extern(providers: &mut ty::maps::Providers) {
2553 *providers = ty::maps::Providers {
2554 adt_sized_constraint,
2555 adt_dtorck_constraint,
2556 trait_impls_of: trait_def::trait_impls_of_provider,
2557 relevant_trait_impls_for: trait_def::relevant_trait_impls_provider,
2558 parameter_environment,
2564 /// A map for the local crate mapping each type to a vector of its
2565 /// inherent impls. This is not meant to be used outside of coherence;
2566 /// rather, you should request the vector for a specific type via
2567 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2568 /// (constructing this map requires touching the entire crate).
2569 #[derive(Clone, Debug)]
2570 pub struct CrateInherentImpls {
2571 pub inherent_impls: DefIdMap<Rc<Vec<DefId>>>,
2574 /// A set of constraints that need to be satisfied in order for
2575 /// a type to be valid for destruction.
2576 #[derive(Clone, Debug)]
2577 pub struct DtorckConstraint<'tcx> {
2578 /// Types that are required to be alive in order for this
2579 /// type to be valid for destruction.
2580 pub outlives: Vec<ty::subst::Kind<'tcx>>,
2581 /// Types that could not be resolved: projections and params.
2582 pub dtorck_types: Vec<Ty<'tcx>>,
2585 impl<'tcx> FromIterator<DtorckConstraint<'tcx>> for DtorckConstraint<'tcx>
2587 fn from_iter<I: IntoIterator<Item=DtorckConstraint<'tcx>>>(iter: I) -> Self {
2588 let mut result = Self::empty();
2590 for constraint in iter {
2591 result.outlives.extend(constraint.outlives);
2592 result.dtorck_types.extend(constraint.dtorck_types);
2600 impl<'tcx> DtorckConstraint<'tcx> {
2601 fn empty() -> DtorckConstraint<'tcx> {
2604 dtorck_types: vec![]
2608 fn dedup<'a>(&mut self) {
2609 let mut outlives = FxHashSet();
2610 let mut dtorck_types = FxHashSet();
2612 self.outlives.retain(|&val| outlives.replace(val).is_none());
2613 self.dtorck_types.retain(|&val| dtorck_types.replace(val).is_none());
2617 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord)]
2618 pub struct SymbolName {
2619 // FIXME: we don't rely on interning or equality here - better have
2620 // this be a `&'tcx str`.
2621 pub name: InternedString
2624 impl Deref for SymbolName {
2627 fn deref(&self) -> &str { &self.name }
2630 impl fmt::Display for SymbolName {
2631 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2632 fmt::Display::fmt(&self.name, fmt)