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::StableHashingContext;
23 use middle::const_val::ConstVal;
24 use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
25 use middle::privacy::AccessLevels;
26 use middle::region::CodeExtent;
27 use middle::resolve_lifetime::ObjectLifetimeDefault;
31 use ty::subst::{Subst, Substs};
32 use ty::util::IntTypeExt;
33 use ty::walk::TypeWalker;
34 use util::common::ErrorReported;
35 use util::nodemap::{NodeSet, DefIdMap, FxHashMap, FxHashSet};
37 use serialize::{self, Encodable, Encoder};
38 use std::cell::{Cell, RefCell};
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, TraitFlags};
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 MOVENESS_CACHED = 1 << 18,
511 const MOVES_BY_DEFAULT = 1 << 19,
512 const FREEZENESS_CACHED = 1 << 20,
513 const IS_FREEZE = 1 << 21,
514 const NEEDS_DROP_CACHED = 1 << 22,
515 const NEEDS_DROP = 1 << 23,
519 pub struct TyS<'tcx> {
520 pub sty: TypeVariants<'tcx>,
521 pub flags: Cell<TypeFlags>,
523 // the maximal depth of any bound regions appearing in this type.
527 impl<'tcx> PartialEq for TyS<'tcx> {
529 fn eq(&self, other: &TyS<'tcx>) -> bool {
530 // (self as *const _) == (other as *const _)
531 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
534 impl<'tcx> Eq for TyS<'tcx> {}
536 impl<'tcx> Hash for TyS<'tcx> {
537 fn hash<H: Hasher>(&self, s: &mut H) {
538 (self as *const TyS).hash(s)
542 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for ty::TyS<'tcx> {
543 fn hash_stable<W: StableHasherResult>(&self,
544 hcx: &mut StableHashingContext<'a, 'tcx>,
545 hasher: &mut StableHasher<W>) {
549 // The other fields just provide fast access to information that is
550 // also contained in `sty`, so no need to hash them.
555 sty.hash_stable(hcx, hasher);
559 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
561 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
562 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
564 /// A wrapper for slices with the additional invariant
565 /// that the slice is interned and no other slice with
566 /// the same contents can exist in the same context.
567 /// This means we can use pointer + length for both
568 /// equality comparisons and hashing.
569 #[derive(Debug, RustcEncodable)]
570 pub struct Slice<T>([T]);
572 impl<T> PartialEq for Slice<T> {
574 fn eq(&self, other: &Slice<T>) -> bool {
575 (&self.0 as *const [T]) == (&other.0 as *const [T])
578 impl<T> Eq for Slice<T> {}
580 impl<T> Hash for Slice<T> {
581 fn hash<H: Hasher>(&self, s: &mut H) {
582 (self.as_ptr(), self.len()).hash(s)
586 impl<T> Deref for Slice<T> {
588 fn deref(&self) -> &[T] {
593 impl<'a, T> IntoIterator for &'a Slice<T> {
595 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
596 fn into_iter(self) -> Self::IntoIter {
601 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {}
604 pub fn empty<'a>() -> &'a Slice<T> {
606 mem::transmute(slice::from_raw_parts(0x1 as *const T, 0))
611 /// Upvars do not get their own node-id. Instead, we use the pair of
612 /// the original var id (that is, the root variable that is referenced
613 /// by the upvar) and the id of the closure expression.
614 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
617 pub closure_expr_id: NodeId,
620 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
621 pub enum BorrowKind {
622 /// Data must be immutable and is aliasable.
625 /// Data must be immutable but not aliasable. This kind of borrow
626 /// cannot currently be expressed by the user and is used only in
627 /// implicit closure bindings. It is needed when the closure
628 /// is borrowing or mutating a mutable referent, e.g.:
630 /// let x: &mut isize = ...;
631 /// let y = || *x += 5;
633 /// If we were to try to translate this closure into a more explicit
634 /// form, we'd encounter an error with the code as written:
636 /// struct Env { x: & &mut isize }
637 /// let x: &mut isize = ...;
638 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
639 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
641 /// This is then illegal because you cannot mutate a `&mut` found
642 /// in an aliasable location. To solve, you'd have to translate with
643 /// an `&mut` borrow:
645 /// struct Env { x: & &mut isize }
646 /// let x: &mut isize = ...;
647 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
648 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
650 /// Now the assignment to `**env.x` is legal, but creating a
651 /// mutable pointer to `x` is not because `x` is not mutable. We
652 /// could fix this by declaring `x` as `let mut x`. This is ok in
653 /// user code, if awkward, but extra weird for closures, since the
654 /// borrow is hidden.
656 /// So we introduce a "unique imm" borrow -- the referent is
657 /// immutable, but not aliasable. This solves the problem. For
658 /// simplicity, we don't give users the way to express this
659 /// borrow, it's just used when translating closures.
662 /// Data is mutable and not aliasable.
666 /// Information describing the capture of an upvar. This is computed
667 /// during `typeck`, specifically by `regionck`.
668 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
669 pub enum UpvarCapture<'tcx> {
670 /// Upvar is captured by value. This is always true when the
671 /// closure is labeled `move`, but can also be true in other cases
672 /// depending on inference.
675 /// Upvar is captured by reference.
676 ByRef(UpvarBorrow<'tcx>),
679 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
680 pub struct UpvarBorrow<'tcx> {
681 /// The kind of borrow: by-ref upvars have access to shared
682 /// immutable borrows, which are not part of the normal language
684 pub kind: BorrowKind,
686 /// Region of the resulting reference.
687 pub region: ty::Region<'tcx>,
690 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
692 #[derive(Copy, Clone)]
693 pub struct ClosureUpvar<'tcx> {
699 #[derive(Clone, Copy, PartialEq)]
700 pub enum IntVarValue {
702 UintType(ast::UintTy),
705 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
706 pub struct TypeParameterDef {
710 pub has_default: bool,
711 pub object_lifetime_default: ObjectLifetimeDefault,
713 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
714 /// on generic parameter `T`, asserts data behind the parameter
715 /// `T` won't be accessed during the parent type's `Drop` impl.
716 pub pure_wrt_drop: bool,
719 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
720 pub struct RegionParameterDef {
724 pub issue_32330: Option<ty::Issue32330>,
726 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
727 /// on generic parameter `'a`, asserts data of lifetime `'a`
728 /// won't be accessed during the parent type's `Drop` impl.
729 pub pure_wrt_drop: bool,
732 impl RegionParameterDef {
733 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
734 ty::EarlyBoundRegion {
740 pub fn to_bound_region(&self) -> ty::BoundRegion {
741 ty::BoundRegion::BrNamed(self.def_id, self.name)
745 /// Information about the formal type/lifetime parameters associated
746 /// with an item or method. Analogous to hir::Generics.
747 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
748 pub struct Generics {
749 pub parent: Option<DefId>,
750 pub parent_regions: u32,
751 pub parent_types: u32,
752 pub regions: Vec<RegionParameterDef>,
753 pub types: Vec<TypeParameterDef>,
755 /// Reverse map to each `TypeParameterDef`'s `index` field, from
756 /// `def_id.index` (`def_id.krate` is the same as the item's).
757 pub type_param_to_index: BTreeMap<DefIndex, u32>,
763 pub fn parent_count(&self) -> usize {
764 self.parent_regions as usize + self.parent_types as usize
767 pub fn own_count(&self) -> usize {
768 self.regions.len() + self.types.len()
771 pub fn count(&self) -> usize {
772 self.parent_count() + self.own_count()
775 pub fn region_param(&self, param: &EarlyBoundRegion) -> &RegionParameterDef {
776 assert_eq!(self.parent_count(), 0);
777 &self.regions[param.index as usize - self.has_self as usize]
780 pub fn type_param(&self, param: &ParamTy) -> &TypeParameterDef {
781 assert_eq!(self.parent_count(), 0);
782 &self.types[param.idx as usize - self.has_self as usize - self.regions.len()]
786 /// Bounds on generics.
787 #[derive(Clone, Default)]
788 pub struct GenericPredicates<'tcx> {
789 pub parent: Option<DefId>,
790 pub predicates: Vec<Predicate<'tcx>>,
793 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
794 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
796 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
797 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
798 -> InstantiatedPredicates<'tcx> {
799 let mut instantiated = InstantiatedPredicates::empty();
800 self.instantiate_into(tcx, &mut instantiated, substs);
803 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
804 -> InstantiatedPredicates<'tcx> {
805 InstantiatedPredicates {
806 predicates: self.predicates.subst(tcx, substs)
810 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
811 instantiated: &mut InstantiatedPredicates<'tcx>,
812 substs: &Substs<'tcx>) {
813 if let Some(def_id) = self.parent {
814 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
816 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
819 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
820 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
821 -> InstantiatedPredicates<'tcx>
823 assert_eq!(self.parent, None);
824 InstantiatedPredicates {
825 predicates: self.predicates.iter().map(|pred| {
826 pred.subst_supertrait(tcx, poly_trait_ref)
832 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
833 pub enum Predicate<'tcx> {
834 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
835 /// the `Self` type of the trait reference and `A`, `B`, and `C`
836 /// would be the type parameters.
837 Trait(PolyTraitPredicate<'tcx>),
839 /// where `T1 == T2`.
840 Equate(PolyEquatePredicate<'tcx>),
843 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
846 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
848 /// where <T as TraitRef>::Name == X, approximately.
849 /// See `ProjectionPredicate` struct for details.
850 Projection(PolyProjectionPredicate<'tcx>),
853 WellFormed(Ty<'tcx>),
855 /// trait must be object-safe
858 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
859 /// for some substitutions `...` and T being a closure type.
860 /// Satisfied (or refuted) once we know the closure's kind.
861 ClosureKind(DefId, ClosureKind),
864 Subtype(PolySubtypePredicate<'tcx>),
867 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
868 /// Performs a substitution suitable for going from a
869 /// poly-trait-ref to supertraits that must hold if that
870 /// poly-trait-ref holds. This is slightly different from a normal
871 /// substitution in terms of what happens with bound regions. See
872 /// lengthy comment below for details.
873 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
874 trait_ref: &ty::PolyTraitRef<'tcx>)
875 -> ty::Predicate<'tcx>
877 // The interaction between HRTB and supertraits is not entirely
878 // obvious. Let me walk you (and myself) through an example.
880 // Let's start with an easy case. Consider two traits:
882 // trait Foo<'a> : Bar<'a,'a> { }
883 // trait Bar<'b,'c> { }
885 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
886 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
887 // knew that `Foo<'x>` (for any 'x) then we also know that
888 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
889 // normal substitution.
891 // In terms of why this is sound, the idea is that whenever there
892 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
893 // holds. So if there is an impl of `T:Foo<'a>` that applies to
894 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
897 // Another example to be careful of is this:
899 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
900 // trait Bar1<'b,'c> { }
902 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
903 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
904 // reason is similar to the previous example: any impl of
905 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
906 // basically we would want to collapse the bound lifetimes from
907 // the input (`trait_ref`) and the supertraits.
909 // To achieve this in practice is fairly straightforward. Let's
910 // consider the more complicated scenario:
912 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
913 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
914 // where both `'x` and `'b` would have a DB index of 1.
915 // The substitution from the input trait-ref is therefore going to be
916 // `'a => 'x` (where `'x` has a DB index of 1).
917 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
918 // early-bound parameter and `'b' is a late-bound parameter with a
920 // - If we replace `'a` with `'x` from the input, it too will have
921 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
922 // just as we wanted.
924 // There is only one catch. If we just apply the substitution `'a
925 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
926 // adjust the DB index because we substituting into a binder (it
927 // tries to be so smart...) resulting in `for<'x> for<'b>
928 // Bar1<'x,'b>` (we have no syntax for this, so use your
929 // imagination). Basically the 'x will have DB index of 2 and 'b
930 // will have DB index of 1. Not quite what we want. So we apply
931 // the substitution to the *contents* of the trait reference,
932 // rather than the trait reference itself (put another way, the
933 // substitution code expects equal binding levels in the values
934 // from the substitution and the value being substituted into, and
935 // this trick achieves that).
937 let substs = &trait_ref.0.substs;
939 Predicate::Trait(ty::Binder(ref data)) =>
940 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
941 Predicate::Equate(ty::Binder(ref data)) =>
942 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
943 Predicate::Subtype(ty::Binder(ref data)) =>
944 Predicate::Subtype(ty::Binder(data.subst(tcx, substs))),
945 Predicate::RegionOutlives(ty::Binder(ref data)) =>
946 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
947 Predicate::TypeOutlives(ty::Binder(ref data)) =>
948 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
949 Predicate::Projection(ty::Binder(ref data)) =>
950 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
951 Predicate::WellFormed(data) =>
952 Predicate::WellFormed(data.subst(tcx, substs)),
953 Predicate::ObjectSafe(trait_def_id) =>
954 Predicate::ObjectSafe(trait_def_id),
955 Predicate::ClosureKind(closure_def_id, kind) =>
956 Predicate::ClosureKind(closure_def_id, kind),
961 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
962 pub struct TraitPredicate<'tcx> {
963 pub trait_ref: TraitRef<'tcx>
965 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
967 impl<'tcx> TraitPredicate<'tcx> {
968 pub fn def_id(&self) -> DefId {
969 self.trait_ref.def_id
972 /// Creates the dep-node for selecting/evaluating this trait reference.
973 fn dep_node(&self) -> DepNode<DefId> {
974 // Extact the trait-def and first def-id from inputs. See the
975 // docs for `DepNode::TraitSelect` for more information.
976 let trait_def_id = self.def_id();
979 .flat_map(|t| t.walk())
980 .filter_map(|t| match t.sty {
981 ty::TyAdt(adt_def, _) => Some(adt_def.did),
985 .unwrap_or(trait_def_id);
986 DepNode::TraitSelect {
987 trait_def_id: trait_def_id,
988 input_def_id: input_def_id
992 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
993 self.trait_ref.input_types()
996 pub fn self_ty(&self) -> Ty<'tcx> {
997 self.trait_ref.self_ty()
1001 impl<'tcx> PolyTraitPredicate<'tcx> {
1002 pub fn def_id(&self) -> DefId {
1003 // ok to skip binder since trait def-id does not care about regions
1007 pub fn dep_node(&self) -> DepNode<DefId> {
1008 // ok to skip binder since depnode does not care about regions
1013 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1014 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
1015 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
1017 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1018 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
1019 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1020 pub type PolyRegionOutlivesPredicate<'tcx> = PolyOutlivesPredicate<ty::Region<'tcx>,
1022 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
1024 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1025 pub struct SubtypePredicate<'tcx> {
1026 pub a_is_expected: bool,
1030 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1032 /// This kind of predicate has no *direct* correspondent in the
1033 /// syntax, but it roughly corresponds to the syntactic forms:
1035 /// 1. `T : TraitRef<..., Item=Type>`
1036 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1038 /// In particular, form #1 is "desugared" to the combination of a
1039 /// normal trait predicate (`T : TraitRef<...>`) and one of these
1040 /// predicates. Form #2 is a broader form in that it also permits
1041 /// equality between arbitrary types. Processing an instance of Form
1042 /// #2 eventually yields one of these `ProjectionPredicate`
1043 /// instances to normalize the LHS.
1044 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1045 pub struct ProjectionPredicate<'tcx> {
1046 pub projection_ty: ProjectionTy<'tcx>,
1050 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1052 impl<'tcx> PolyProjectionPredicate<'tcx> {
1053 pub fn item_name(&self) -> Name {
1054 self.0.projection_ty.item_name // safe to skip the binder to access a name
1058 pub trait ToPolyTraitRef<'tcx> {
1059 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1062 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1063 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1064 assert!(!self.has_escaping_regions());
1065 ty::Binder(self.clone())
1069 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1070 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1071 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1075 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
1076 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1077 // Note: unlike with TraitRef::to_poly_trait_ref(),
1078 // self.0.trait_ref is permitted to have escaping regions.
1079 // This is because here `self` has a `Binder` and so does our
1080 // return value, so we are preserving the number of binding
1082 ty::Binder(self.0.projection_ty.trait_ref)
1086 pub trait ToPredicate<'tcx> {
1087 fn to_predicate(&self) -> Predicate<'tcx>;
1090 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1091 fn to_predicate(&self) -> Predicate<'tcx> {
1092 // we're about to add a binder, so let's check that we don't
1093 // accidentally capture anything, or else that might be some
1094 // weird debruijn accounting.
1095 assert!(!self.has_escaping_regions());
1097 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
1098 trait_ref: self.clone()
1103 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1104 fn to_predicate(&self) -> Predicate<'tcx> {
1105 ty::Predicate::Trait(self.to_poly_trait_predicate())
1109 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
1110 fn to_predicate(&self) -> Predicate<'tcx> {
1111 Predicate::Equate(self.clone())
1115 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1116 fn to_predicate(&self) -> Predicate<'tcx> {
1117 Predicate::RegionOutlives(self.clone())
1121 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1122 fn to_predicate(&self) -> Predicate<'tcx> {
1123 Predicate::TypeOutlives(self.clone())
1127 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1128 fn to_predicate(&self) -> Predicate<'tcx> {
1129 Predicate::Projection(self.clone())
1133 impl<'tcx> Predicate<'tcx> {
1134 /// Iterates over the types in this predicate. Note that in all
1135 /// cases this is skipping over a binder, so late-bound regions
1136 /// with depth 0 are bound by the predicate.
1137 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1138 let vec: Vec<_> = match *self {
1139 ty::Predicate::Trait(ref data) => {
1140 data.skip_binder().input_types().collect()
1142 ty::Predicate::Equate(ty::Binder(ref data)) => {
1143 vec![data.0, data.1]
1145 ty::Predicate::Subtype(ty::Binder(SubtypePredicate { a, b, a_is_expected: _ })) => {
1148 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
1151 ty::Predicate::RegionOutlives(..) => {
1154 ty::Predicate::Projection(ref data) => {
1155 let trait_inputs = data.0.projection_ty.trait_ref.input_types();
1156 trait_inputs.chain(Some(data.0.ty)).collect()
1158 ty::Predicate::WellFormed(data) => {
1161 ty::Predicate::ObjectSafe(_trait_def_id) => {
1164 ty::Predicate::ClosureKind(_closure_def_id, _kind) => {
1169 // The only reason to collect into a vector here is that I was
1170 // too lazy to make the full (somewhat complicated) iterator
1171 // type that would be needed here. But I wanted this fn to
1172 // return an iterator conceptually, rather than a `Vec`, so as
1173 // to be closer to `Ty::walk`.
1177 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1179 Predicate::Trait(ref t) => {
1180 Some(t.to_poly_trait_ref())
1182 Predicate::Projection(..) |
1183 Predicate::Equate(..) |
1184 Predicate::Subtype(..) |
1185 Predicate::RegionOutlives(..) |
1186 Predicate::WellFormed(..) |
1187 Predicate::ObjectSafe(..) |
1188 Predicate::ClosureKind(..) |
1189 Predicate::TypeOutlives(..) => {
1196 /// Represents the bounds declared on a particular set of type
1197 /// parameters. Should eventually be generalized into a flag list of
1198 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1199 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1200 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1201 /// the `GenericPredicates` are expressed in terms of the bound type
1202 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1203 /// represented a set of bounds for some particular instantiation,
1204 /// meaning that the generic parameters have been substituted with
1209 /// struct Foo<T,U:Bar<T>> { ... }
1211 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1212 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1213 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1214 /// [usize:Bar<isize>]]`.
1216 pub struct InstantiatedPredicates<'tcx> {
1217 pub predicates: Vec<Predicate<'tcx>>,
1220 impl<'tcx> InstantiatedPredicates<'tcx> {
1221 pub fn empty() -> InstantiatedPredicates<'tcx> {
1222 InstantiatedPredicates { predicates: vec![] }
1225 pub fn is_empty(&self) -> bool {
1226 self.predicates.is_empty()
1230 /// When type checking, we use the `ParameterEnvironment` to track
1231 /// details about the type/lifetime parameters that are in scope.
1232 /// It primarily stores the bounds information.
1234 /// Note: This information might seem to be redundant with the data in
1235 /// `tcx.ty_param_defs`, but it is not. That table contains the
1236 /// parameter definitions from an "outside" perspective, but this
1237 /// struct will contain the bounds for a parameter as seen from inside
1238 /// the function body. Currently the only real distinction is that
1239 /// bound lifetime parameters are replaced with free ones, but in the
1240 /// future I hope to refine the representation of types so as to make
1241 /// more distinctions clearer.
1243 pub struct ParameterEnvironment<'tcx> {
1244 /// See `construct_free_substs` for details.
1245 pub free_substs: &'tcx Substs<'tcx>,
1247 /// Each type parameter has an implicit region bound that
1248 /// indicates it must outlive at least the function body (the user
1249 /// may specify stronger requirements). This field indicates the
1250 /// region of the callee. If it is `None`, then the parameter
1251 /// environment is for an item or something where the "callee" is
1253 pub implicit_region_bound: Option<ty::Region<'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 [ty::Predicate<'tcx>],
1260 /// Scope that is attached to free regions for this scope. This is
1261 /// usually the id of the fn body, but for more abstract scopes
1262 /// like structs we use None or the item extent.
1264 /// FIXME(#3696). It would be nice to refactor so that free
1265 /// regions don't have this implicit scope and instead introduce
1266 /// relationships in the environment.
1267 pub free_id_outlive: Option<CodeExtent<'tcx>>,
1269 /// A cache for `moves_by_default`.
1270 pub is_copy_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1272 /// A cache for `type_is_sized`
1273 pub is_sized_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1275 /// A cache for `type_is_freeze`
1276 pub is_freeze_cache: RefCell<FxHashMap<Ty<'tcx>, bool>>,
1279 impl<'a, 'tcx> ParameterEnvironment<'tcx> {
1280 pub fn with_caller_bounds(&self,
1281 caller_bounds: &'tcx [ty::Predicate<'tcx>])
1282 -> ParameterEnvironment<'tcx>
1284 ParameterEnvironment {
1285 free_substs: self.free_substs,
1286 implicit_region_bound: self.implicit_region_bound,
1287 caller_bounds: caller_bounds,
1288 free_id_outlive: self.free_id_outlive,
1289 is_copy_cache: RefCell::new(FxHashMap()),
1290 is_sized_cache: RefCell::new(FxHashMap()),
1291 is_freeze_cache: RefCell::new(FxHashMap()),
1295 /// Construct a parameter environment given an item, impl item, or trait item
1296 pub fn for_item(tcx: TyCtxt<'a, 'tcx, 'tcx>, id: NodeId)
1297 -> ParameterEnvironment<'tcx> {
1298 match tcx.hir.find(id) {
1299 Some(hir_map::NodeImplItem(ref impl_item)) => {
1300 match impl_item.node {
1301 hir::ImplItemKind::Type(_) => {
1302 // associated types don't have their own entry (for some reason),
1303 // so for now just grab environment for the impl
1304 let impl_id = tcx.hir.get_parent(id);
1305 let impl_def_id = tcx.hir.local_def_id(impl_id);
1306 tcx.construct_parameter_environment(impl_item.span,
1308 Some(tcx.item_extent(id)))
1310 hir::ImplItemKind::Const(_, body) |
1311 hir::ImplItemKind::Method(_, body) => {
1312 tcx.construct_parameter_environment(
1314 tcx.hir.local_def_id(id),
1315 Some(tcx.call_site_extent(id, body.node_id)))
1319 Some(hir_map::NodeTraitItem(trait_item)) => {
1320 match trait_item.node {
1321 hir::TraitItemKind::Type(..) |
1322 hir::TraitItemKind::Const(_, None) |
1323 hir::TraitItemKind::Method(_, hir::TraitMethod::Required(_))=> {
1324 tcx.construct_parameter_environment(trait_item.span,
1325 tcx.hir.local_def_id(id),
1326 Some(tcx.item_extent(id)))
1328 hir::TraitItemKind::Const(_, Some(body)) |
1329 hir::TraitItemKind::Method(_, hir::TraitMethod::Provided(body)) => {
1330 tcx.construct_parameter_environment(
1332 tcx.hir.local_def_id(id),
1333 Some(tcx.call_site_extent(id, body.node_id)))
1337 Some(hir_map::NodeItem(item)) => {
1339 hir::ItemConst(_, body) |
1340 hir::ItemStatic(.., body) |
1341 hir::ItemFn(.., body) => {
1342 tcx.construct_parameter_environment(
1344 tcx.hir.local_def_id(id),
1345 Some(tcx.call_site_extent(id, body.node_id)))
1348 hir::ItemStruct(..) |
1349 hir::ItemUnion(..) |
1352 hir::ItemTrait(..) => {
1353 let def_id = tcx.hir.local_def_id(id);
1354 tcx.construct_parameter_environment(item.span,
1356 Some(tcx.item_extent(id)))
1359 span_bug!(item.span,
1360 "ParameterEnvironment::for_item():
1361 can't create a parameter \
1362 environment for this kind of item")
1366 Some(hir_map::NodeExpr(expr)) => {
1367 // This is a convenience to allow closures to work.
1368 if let hir::ExprClosure(.., body, _) = expr.node {
1369 let def_id = tcx.hir.local_def_id(id);
1370 let base_def_id = tcx.closure_base_def_id(def_id);
1371 tcx.construct_parameter_environment(
1374 Some(tcx.call_site_extent(id, body.node_id)))
1376 tcx.empty_parameter_environment()
1379 Some(hir_map::NodeForeignItem(item)) => {
1380 let def_id = tcx.hir.local_def_id(id);
1381 tcx.construct_parameter_environment(item.span,
1385 Some(hir_map::NodeStructCtor(..)) |
1386 Some(hir_map::NodeVariant(..)) => {
1387 let def_id = tcx.hir.local_def_id(id);
1388 tcx.construct_parameter_environment(tcx.hir.span(id),
1393 bug!("ParameterEnvironment::from_item(): \
1394 `{}` = {:?} is unsupported",
1395 tcx.hir.node_to_string(id), it)
1401 #[derive(Copy, Clone, Debug)]
1402 pub struct Destructor {
1403 /// The def-id of the destructor method
1408 flags AdtFlags: u32 {
1409 const NO_ADT_FLAGS = 0,
1410 const IS_ENUM = 1 << 0,
1411 const IS_PHANTOM_DATA = 1 << 1,
1412 const IS_FUNDAMENTAL = 1 << 2,
1413 const IS_UNION = 1 << 3,
1414 const IS_BOX = 1 << 4,
1419 pub struct VariantDef {
1420 /// The variant's DefId. If this is a tuple-like struct,
1421 /// this is the DefId of the struct's ctor.
1423 pub name: Name, // struct's name if this is a struct
1424 pub discr: VariantDiscr,
1425 pub fields: Vec<FieldDef>,
1426 pub ctor_kind: CtorKind,
1429 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1430 pub enum VariantDiscr {
1431 /// Explicit value for this variant, i.e. `X = 123`.
1432 /// The `DefId` corresponds to the embedded constant.
1435 /// The previous variant's discriminant plus one.
1436 /// For efficiency reasons, the distance from the
1437 /// last `Explicit` discriminant is being stored,
1438 /// or `0` for the first variant, if it has none.
1443 pub struct FieldDef {
1446 pub vis: Visibility,
1449 /// The definition of an abstract data type - a struct or enum.
1451 /// These are all interned (by intern_adt_def) into the adt_defs
1455 pub variants: Vec<VariantDef>,
1457 pub repr: ReprOptions,
1460 impl PartialEq for AdtDef {
1461 // AdtDef are always interned and this is part of TyS equality
1463 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1466 impl Eq for AdtDef {}
1468 impl Hash for AdtDef {
1470 fn hash<H: Hasher>(&self, s: &mut H) {
1471 (self as *const AdtDef).hash(s)
1475 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1476 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1481 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1484 impl<'a, 'tcx> HashStable<StableHashingContext<'a, 'tcx>> for AdtDef {
1485 fn hash_stable<W: StableHasherResult>(&self,
1486 hcx: &mut StableHashingContext<'a, 'tcx>,
1487 hasher: &mut StableHasher<W>) {
1495 did.hash_stable(hcx, hasher);
1496 variants.hash_stable(hcx, hasher);
1497 flags.hash_stable(hcx, hasher);
1498 repr.hash_stable(hcx, hasher);
1502 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1503 pub enum AdtKind { Struct, Union, Enum }
1506 #[derive(RustcEncodable, RustcDecodable, Default)]
1507 flags ReprFlags: u8 {
1508 const IS_C = 1 << 0,
1509 const IS_PACKED = 1 << 1,
1510 const IS_SIMD = 1 << 2,
1511 // Internal only for now. If true, don't reorder fields.
1512 const IS_LINEAR = 1 << 3,
1514 // Any of these flags being set prevent field reordering optimisation.
1515 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1516 ReprFlags::IS_PACKED.bits |
1517 ReprFlags::IS_SIMD.bits |
1518 ReprFlags::IS_LINEAR.bits,
1522 impl_stable_hash_for!(struct ReprFlags {
1528 /// Represents the repr options provided by the user,
1529 #[derive(Copy, Clone, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1530 pub struct ReprOptions {
1531 pub int: Option<attr::IntType>,
1533 pub flags: ReprFlags,
1536 impl_stable_hash_for!(struct ReprOptions {
1543 pub fn new(tcx: TyCtxt, did: DefId) -> ReprOptions {
1544 let mut flags = ReprFlags::empty();
1545 let mut size = None;
1546 let mut max_align = 0;
1547 for attr in tcx.get_attrs(did).iter() {
1548 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1549 flags.insert(match r {
1550 attr::ReprExtern => ReprFlags::IS_C,
1551 attr::ReprPacked => ReprFlags::IS_PACKED,
1552 attr::ReprSimd => ReprFlags::IS_SIMD,
1553 attr::ReprInt(i) => {
1557 attr::ReprAlign(align) => {
1558 max_align = cmp::max(align, max_align);
1565 // FIXME(eddyb) This is deprecated and should be removed.
1566 if tcx.has_attr(did, "simd") {
1567 flags.insert(ReprFlags::IS_SIMD);
1570 // This is here instead of layout because the choice must make it into metadata.
1571 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1572 flags.insert(ReprFlags::IS_LINEAR);
1574 ReprOptions { int: size, align: max_align, flags: flags }
1578 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1580 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1582 pub fn packed(&self) -> bool { self.flags.contains(ReprFlags::IS_PACKED) }
1584 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1586 pub fn discr_type(&self) -> attr::IntType {
1587 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Is))
1590 /// Returns true if this `#[repr()]` should inhabit "smart enum
1591 /// layout" optimizations, such as representing `Foo<&T>` as a
1593 pub fn inhibit_enum_layout_opt(&self) -> bool {
1594 self.c() || self.int.is_some()
1598 impl<'a, 'gcx, 'tcx> AdtDef {
1602 variants: Vec<VariantDef>,
1603 repr: ReprOptions) -> Self {
1604 let mut flags = AdtFlags::NO_ADT_FLAGS;
1605 let attrs = tcx.get_attrs(did);
1606 if attr::contains_name(&attrs, "fundamental") {
1607 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1609 if Some(did) == tcx.lang_items.phantom_data() {
1610 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1612 if Some(did) == tcx.lang_items.owned_box() {
1613 flags = flags | AdtFlags::IS_BOX;
1616 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
1617 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
1618 AdtKind::Struct => {}
1629 pub fn is_struct(&self) -> bool {
1630 !self.is_union() && !self.is_enum()
1634 pub fn is_union(&self) -> bool {
1635 self.flags.intersects(AdtFlags::IS_UNION)
1639 pub fn is_enum(&self) -> bool {
1640 self.flags.intersects(AdtFlags::IS_ENUM)
1643 /// Returns the kind of the ADT - Struct or Enum.
1645 pub fn adt_kind(&self) -> AdtKind {
1648 } else if self.is_union() {
1655 pub fn descr(&self) -> &'static str {
1656 match self.adt_kind() {
1657 AdtKind::Struct => "struct",
1658 AdtKind::Union => "union",
1659 AdtKind::Enum => "enum",
1663 pub fn variant_descr(&self) -> &'static str {
1664 match self.adt_kind() {
1665 AdtKind::Struct => "struct",
1666 AdtKind::Union => "union",
1667 AdtKind::Enum => "variant",
1671 /// Returns whether this type is #[fundamental] for the purposes
1672 /// of coherence checking.
1674 pub fn is_fundamental(&self) -> bool {
1675 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
1678 /// Returns true if this is PhantomData<T>.
1680 pub fn is_phantom_data(&self) -> bool {
1681 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
1684 /// Returns true if this is Box<T>.
1686 pub fn is_box(&self) -> bool {
1687 self.flags.intersects(AdtFlags::IS_BOX)
1690 /// Returns whether this type has a destructor.
1691 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
1692 self.destructor(tcx).is_some()
1695 /// Asserts this is a struct and returns the struct's unique
1697 pub fn struct_variant(&self) -> &VariantDef {
1698 assert!(!self.is_enum());
1703 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
1704 tcx.predicates_of(self.did)
1707 /// Returns an iterator over all fields contained
1710 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
1711 self.variants.iter().flat_map(|v| v.fields.iter())
1715 pub fn is_univariant(&self) -> bool {
1716 self.variants.len() == 1
1719 pub fn is_payloadfree(&self) -> bool {
1720 !self.variants.is_empty() &&
1721 self.variants.iter().all(|v| v.fields.is_empty())
1724 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
1727 .find(|v| v.did == vid)
1728 .expect("variant_with_id: unknown variant")
1731 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1734 .position(|v| v.did == vid)
1735 .expect("variant_index_with_id: unknown variant")
1738 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
1740 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
1741 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
1742 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.struct_variant(),
1743 _ => bug!("unexpected def {:?} in variant_of_def", def)
1748 pub fn discriminants(&'a self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1749 -> impl Iterator<Item=ConstInt> + 'a {
1750 let repr_type = self.repr.discr_type();
1751 let initial = repr_type.initial_discriminant(tcx.global_tcx());
1752 let mut prev_discr = None::<ConstInt>;
1753 self.variants.iter().map(move |v| {
1754 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr());
1755 if let VariantDiscr::Explicit(expr_did) = v.discr {
1756 let substs = Substs::empty();
1757 match tcx.const_eval((expr_did, substs)) {
1758 Ok(ConstVal::Integral(v)) => {
1762 if !expr_did.is_local() {
1763 span_bug!(tcx.def_span(expr_did),
1764 "variant discriminant evaluation succeeded \
1765 in its crate but failed locally: {:?}", err);
1770 prev_discr = Some(discr);
1776 /// Compute the discriminant value used by a specific variant.
1777 /// Unlike `discriminants`, this is (amortized) constant-time,
1778 /// only doing at most one query for evaluating an explicit
1779 /// discriminant (the last one before the requested variant),
1780 /// assuming there are no constant-evaluation errors there.
1781 pub fn discriminant_for_variant(&self,
1782 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1783 variant_index: usize)
1785 let repr_type = self.repr.discr_type();
1786 let mut explicit_value = repr_type.initial_discriminant(tcx.global_tcx());
1787 let mut explicit_index = variant_index;
1789 match self.variants[explicit_index].discr {
1790 ty::VariantDiscr::Relative(0) => break,
1791 ty::VariantDiscr::Relative(distance) => {
1792 explicit_index -= distance;
1794 ty::VariantDiscr::Explicit(expr_did) => {
1795 let substs = Substs::empty();
1796 match tcx.const_eval((expr_did, substs)) {
1797 Ok(ConstVal::Integral(v)) => {
1802 if !expr_did.is_local() {
1803 span_bug!(tcx.def_span(expr_did),
1804 "variant discriminant evaluation succeeded \
1805 in its crate but failed locally: {:?}", err);
1807 if explicit_index == 0 {
1810 explicit_index -= 1;
1816 let discr = explicit_value.to_u128_unchecked()
1817 .wrapping_add((variant_index - explicit_index) as u128);
1819 attr::UnsignedInt(ty) => {
1820 ConstInt::new_unsigned_truncating(discr, ty,
1821 tcx.sess.target.uint_type)
1823 attr::SignedInt(ty) => {
1824 ConstInt::new_signed_truncating(discr as i128, ty,
1825 tcx.sess.target.int_type)
1830 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
1831 tcx.adt_destructor(self.did)
1834 /// Returns a list of types such that `Self: Sized` if and only
1835 /// if that type is Sized, or `TyErr` if this type is recursive.
1837 /// Oddly enough, checking that the sized-constraint is Sized is
1838 /// actually more expressive than checking all members:
1839 /// the Sized trait is inductive, so an associated type that references
1840 /// Self would prevent its containing ADT from being Sized.
1842 /// Due to normalization being eager, this applies even if
1843 /// the associated type is behind a pointer, e.g. issue #31299.
1844 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
1845 match queries::adt_sized_constraint::try_get(tcx, DUMMY_SP, self.did) {
1848 debug!("adt_sized_constraint: {:?} is recursive", self);
1849 // This should be reported as an error by `check_representable`.
1851 // Consider the type as Sized in the meanwhile to avoid
1853 tcx.intern_type_list(&[tcx.types.err])
1858 fn sized_constraint_for_ty(&self,
1859 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1862 let result = match ty.sty {
1863 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
1864 TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
1865 TyArray(..) | TyClosure(..) | TyNever => {
1869 TyStr | TyDynamic(..) | TySlice(_) | TyError => {
1870 // these are never sized - return the target type
1874 TyTuple(ref tys, _) => {
1877 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
1881 TyAdt(adt, substs) => {
1883 let adt_tys = adt.sized_constraint(tcx);
1884 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
1887 .map(|ty| ty.subst(tcx, substs))
1888 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
1892 TyProjection(..) | TyAnon(..) => {
1893 // must calculate explicitly.
1894 // FIXME: consider special-casing always-Sized projections
1899 // perf hack: if there is a `T: Sized` bound, then
1900 // we know that `T` is Sized and do not need to check
1903 let sized_trait = match tcx.lang_items.sized_trait() {
1905 _ => return vec![ty]
1907 let sized_predicate = Binder(TraitRef {
1908 def_id: sized_trait,
1909 substs: tcx.mk_substs_trait(ty, &[])
1911 let predicates = tcx.predicates_of(self.did).predicates;
1912 if predicates.into_iter().any(|p| p == sized_predicate) {
1920 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
1924 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
1929 impl<'a, 'gcx, 'tcx> VariantDef {
1931 pub fn find_field_named(&self,
1933 -> Option<&FieldDef> {
1934 self.fields.iter().find(|f| f.name == name)
1938 pub fn index_of_field_named(&self,
1941 self.fields.iter().position(|f| f.name == name)
1945 pub fn field_named(&self, name: ast::Name) -> &FieldDef {
1946 self.find_field_named(name).unwrap()
1950 impl<'a, 'gcx, 'tcx> FieldDef {
1951 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1952 tcx.type_of(self.did).subst(tcx, subst)
1956 /// Records the substitutions used to translate the polytype for an
1957 /// item into the monotype of an item reference.
1958 #[derive(Clone, RustcEncodable, RustcDecodable)]
1959 pub struct ItemSubsts<'tcx> {
1960 pub substs: &'tcx Substs<'tcx>,
1963 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1964 pub enum ClosureKind {
1965 // Warning: Ordering is significant here! The ordering is chosen
1966 // because the trait Fn is a subtrait of FnMut and so in turn, and
1967 // hence we order it so that Fn < FnMut < FnOnce.
1973 impl<'a, 'tcx> ClosureKind {
1974 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
1976 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
1977 ClosureKind::FnMut => {
1978 tcx.require_lang_item(FnMutTraitLangItem)
1980 ClosureKind::FnOnce => {
1981 tcx.require_lang_item(FnOnceTraitLangItem)
1986 /// True if this a type that impls this closure kind
1987 /// must also implement `other`.
1988 pub fn extends(self, other: ty::ClosureKind) -> bool {
1989 match (self, other) {
1990 (ClosureKind::Fn, ClosureKind::Fn) => true,
1991 (ClosureKind::Fn, ClosureKind::FnMut) => true,
1992 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
1993 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
1994 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
1995 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2001 impl<'tcx> TyS<'tcx> {
2002 /// Iterator that walks `self` and any types reachable from
2003 /// `self`, in depth-first order. Note that just walks the types
2004 /// that appear in `self`, it does not descend into the fields of
2005 /// structs or variants. For example:
2008 /// isize => { isize }
2009 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2010 /// [isize] => { [isize], isize }
2012 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2013 TypeWalker::new(self)
2016 /// Iterator that walks the immediate children of `self`. Hence
2017 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2018 /// (but not `i32`, like `walk`).
2019 pub fn walk_shallow(&'tcx self) -> AccIntoIter<walk::TypeWalkerArray<'tcx>> {
2020 walk::walk_shallow(self)
2023 /// Walks `ty` and any types appearing within `ty`, invoking the
2024 /// callback `f` on each type. If the callback returns false, then the
2025 /// children of the current type are ignored.
2027 /// Note: prefer `ty.walk()` where possible.
2028 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2029 where F : FnMut(Ty<'tcx>) -> bool
2031 let mut walker = self.walk();
2032 while let Some(ty) = walker.next() {
2034 walker.skip_current_subtree();
2040 impl<'tcx> ItemSubsts<'tcx> {
2041 pub fn is_noop(&self) -> bool {
2042 self.substs.is_noop()
2046 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
2047 pub enum LvaluePreference {
2052 impl LvaluePreference {
2053 pub fn from_mutbl(m: hir::Mutability) -> Self {
2055 hir::MutMutable => PreferMutLvalue,
2056 hir::MutImmutable => NoPreference,
2062 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2064 hir::MutMutable => MutBorrow,
2065 hir::MutImmutable => ImmBorrow,
2069 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2070 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2071 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2073 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2075 MutBorrow => hir::MutMutable,
2076 ImmBorrow => hir::MutImmutable,
2078 // We have no type corresponding to a unique imm borrow, so
2079 // use `&mut`. It gives all the capabilities of an `&uniq`
2080 // and hence is a safe "over approximation".
2081 UniqueImmBorrow => hir::MutMutable,
2085 pub fn to_user_str(&self) -> &'static str {
2087 MutBorrow => "mutable",
2088 ImmBorrow => "immutable",
2089 UniqueImmBorrow => "uniquely immutable",
2094 #[derive(Debug, Clone)]
2095 pub enum Attributes<'gcx> {
2096 Owned(Rc<[ast::Attribute]>),
2097 Borrowed(&'gcx [ast::Attribute])
2100 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2101 type Target = [ast::Attribute];
2103 fn deref(&self) -> &[ast::Attribute] {
2105 &Attributes::Owned(ref data) => &data,
2106 &Attributes::Borrowed(data) => data
2111 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2112 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2113 self.typeck_tables_of(self.hir.body_owner_def_id(body))
2116 /// Returns an iterator of the def-ids for all body-owners in this
2117 /// crate. If you would prefer to iterate over the bodies
2118 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
2119 pub fn body_owners(self) -> impl Iterator<Item = DefId> + 'a {
2123 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
2126 pub fn expr_span(self, id: NodeId) -> Span {
2127 match self.hir.find(id) {
2128 Some(hir_map::NodeExpr(e)) => {
2132 bug!("Node id {} is not an expr: {:?}", id, f);
2135 bug!("Node id {} is not present in the node map", id);
2140 pub fn local_var_name_str(self, id: NodeId) -> InternedString {
2141 match self.hir.find(id) {
2142 Some(hir_map::NodeLocal(pat)) => {
2144 hir::PatKind::Binding(_, _, ref path1, _) => path1.node.as_str(),
2146 bug!("Variable id {} maps to {:?}, not local", id, pat);
2150 r => bug!("Variable id {} maps to {:?}, not local", id, r),
2154 pub fn expr_is_lval(self, expr: &hir::Expr) -> bool {
2156 hir::ExprPath(hir::QPath::Resolved(_, ref path)) => {
2158 Def::Local(..) | Def::Upvar(..) | Def::Static(..) | Def::Err => true,
2163 hir::ExprType(ref e, _) => {
2164 self.expr_is_lval(e)
2167 hir::ExprUnary(hir::UnDeref, _) |
2168 hir::ExprField(..) |
2169 hir::ExprTupField(..) |
2170 hir::ExprIndex(..) => {
2174 // Partially qualified paths in expressions can only legally
2175 // refer to associated items which are always rvalues.
2176 hir::ExprPath(hir::QPath::TypeRelative(..)) |
2179 hir::ExprMethodCall(..) |
2180 hir::ExprStruct(..) |
2183 hir::ExprMatch(..) |
2184 hir::ExprClosure(..) |
2185 hir::ExprBlock(..) |
2186 hir::ExprRepeat(..) |
2187 hir::ExprArray(..) |
2188 hir::ExprBreak(..) |
2189 hir::ExprAgain(..) |
2191 hir::ExprWhile(..) |
2193 hir::ExprAssign(..) |
2194 hir::ExprInlineAsm(..) |
2195 hir::ExprAssignOp(..) |
2197 hir::ExprUnary(..) |
2199 hir::ExprAddrOf(..) |
2200 hir::ExprBinary(..) |
2201 hir::ExprCast(..) => {
2207 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2208 self.associated_items(id)
2209 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2213 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2214 self.associated_items(did).any(|item| {
2215 item.relevant_for_never()
2219 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2220 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2221 match self.hir.get(node_id) {
2222 hir_map::NodeTraitItem(_) | hir_map::NodeImplItem(_) => true,
2226 match self.describe_def(def_id).expect("no def for def-id") {
2227 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2232 if is_associated_item {
2233 Some(self.associated_item(def_id))
2239 fn associated_item_from_trait_item_ref(self,
2240 parent_def_id: DefId,
2241 parent_vis: &hir::Visibility,
2242 trait_item_ref: &hir::TraitItemRef)
2244 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2245 let (kind, has_self) = match trait_item_ref.kind {
2246 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2247 hir::AssociatedItemKind::Method { has_self } => {
2248 (ty::AssociatedKind::Method, has_self)
2250 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2254 name: trait_item_ref.name,
2256 // Visibility of trait items is inherited from their traits.
2257 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2258 defaultness: trait_item_ref.defaultness,
2260 container: TraitContainer(parent_def_id),
2261 method_has_self_argument: has_self
2265 fn associated_item_from_impl_item_ref(self,
2266 parent_def_id: DefId,
2267 impl_item_ref: &hir::ImplItemRef)
2269 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2270 let (kind, has_self) = match impl_item_ref.kind {
2271 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2272 hir::AssociatedItemKind::Method { has_self } => {
2273 (ty::AssociatedKind::Method, has_self)
2275 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2278 ty::AssociatedItem {
2279 name: impl_item_ref.name,
2281 // Visibility of trait impl items doesn't matter.
2282 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2283 defaultness: impl_item_ref.defaultness,
2285 container: ImplContainer(parent_def_id),
2286 method_has_self_argument: has_self
2290 #[inline] // FIXME(#35870) Avoid closures being unexported due to impl Trait.
2291 pub fn associated_items(self, def_id: DefId)
2292 -> impl Iterator<Item = ty::AssociatedItem> + 'a {
2293 let def_ids = self.associated_item_def_ids(def_id);
2294 (0..def_ids.len()).map(move |i| self.associated_item(def_ids[i]))
2297 /// Returns true if the impls are the same polarity and are implementing
2298 /// a trait which contains no items
2299 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2300 if !self.sess.features.borrow().overlapping_marker_traits {
2303 let trait1_is_empty = self.impl_trait_ref(def_id1)
2304 .map_or(false, |trait_ref| {
2305 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2307 let trait2_is_empty = self.impl_trait_ref(def_id2)
2308 .map_or(false, |trait_ref| {
2309 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2311 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2316 // Returns `ty::VariantDef` if `def` refers to a struct,
2317 // or variant or their constructors, panics otherwise.
2318 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2320 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2321 let enum_did = self.parent_def_id(did).unwrap();
2322 self.adt_def(enum_did).variant_with_id(did)
2324 Def::Struct(did) | Def::Union(did) => {
2325 self.adt_def(did).struct_variant()
2327 Def::StructCtor(ctor_did, ..) => {
2328 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2329 self.adt_def(did).struct_variant()
2331 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2335 pub fn def_key(self, id: DefId) -> hir_map::DefKey {
2337 self.hir.def_key(id)
2339 self.sess.cstore.def_key(id)
2343 /// Convert a `DefId` into its fully expanded `DefPath` (every
2344 /// `DefId` is really just an interned def-path).
2346 /// Note that if `id` is not local to this crate, the result will
2347 /// be a non-local `DefPath`.
2348 pub fn def_path(self, id: DefId) -> hir_map::DefPath {
2350 self.hir.def_path(id)
2352 self.sess.cstore.def_path(id)
2357 pub fn def_path_hash(self, def_id: DefId) -> u64 {
2358 if def_id.is_local() {
2359 self.hir.definitions().def_path_hash(def_id.index)
2361 self.sess.cstore.def_path_hash(def_id)
2365 pub fn vis_is_accessible_from(self, vis: Visibility, block: NodeId) -> bool {
2366 vis.is_accessible_from(self.hir.local_def_id(self.hir.get_module_parent(block)), self)
2369 pub fn item_name(self, id: DefId) -> ast::Name {
2370 if let Some(id) = self.hir.as_local_node_id(id) {
2372 } else if id.index == CRATE_DEF_INDEX {
2373 self.sess.cstore.original_crate_name(id.krate)
2375 let def_key = self.sess.cstore.def_key(id);
2376 // The name of a StructCtor is that of its struct parent.
2377 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2378 self.item_name(DefId {
2380 index: def_key.parent.unwrap()
2383 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2384 bug!("item_name: no name for {:?}", self.def_path(id));
2390 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2391 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2395 ty::InstanceDef::Item(did) => {
2396 self.optimized_mir(did)
2398 ty::InstanceDef::Intrinsic(..) |
2399 ty::InstanceDef::FnPtrShim(..) |
2400 ty::InstanceDef::Virtual(..) |
2401 ty::InstanceDef::ClosureOnceShim { .. } |
2402 ty::InstanceDef::DropGlue(..) => {
2403 self.mir_shims(instance)
2408 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2409 /// Returns None if there is no MIR for the DefId
2410 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2411 if self.is_mir_available(did) {
2412 Some(self.optimized_mir(did))
2418 /// Get the attributes of a definition.
2419 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2420 if let Some(id) = self.hir.as_local_node_id(did) {
2421 Attributes::Borrowed(self.hir.attrs(id))
2423 Attributes::Owned(self.item_attrs(did))
2427 /// Determine whether an item is annotated with an attribute
2428 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2429 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2432 pub fn trait_has_default_impl(self, trait_def_id: DefId) -> bool {
2433 let def = self.trait_def(trait_def_id);
2434 def.flags.get().intersects(TraitFlags::HAS_DEFAULT_IMPL)
2437 /// Populates the type context with all the implementations for the given
2438 /// trait if necessary.
2439 pub fn populate_implementations_for_trait_if_necessary(self, trait_id: DefId) {
2440 if trait_id.is_local() {
2444 // The type is not local, hence we are reading this out of
2445 // metadata and don't need to track edges.
2446 let _ignore = self.dep_graph.in_ignore();
2448 let def = self.trait_def(trait_id);
2449 if def.flags.get().intersects(TraitFlags::HAS_REMOTE_IMPLS) {
2453 debug!("populate_implementations_for_trait_if_necessary: searching for {:?}", def);
2455 for impl_def_id in self.sess.cstore.implementations_of_trait(Some(trait_id)) {
2456 let trait_ref = self.impl_trait_ref(impl_def_id).unwrap();
2458 // Record the trait->implementation mapping.
2459 let parent = self.impl_parent(impl_def_id).unwrap_or(trait_id);
2460 def.record_remote_impl(self, impl_def_id, trait_ref, parent);
2463 def.flags.set(def.flags.get() | TraitFlags::HAS_REMOTE_IMPLS);
2466 /// Given the def_id of an impl, return the def_id of the trait it implements.
2467 /// If it implements no trait, return `None`.
2468 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2469 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2472 /// If the given def ID describes a method belonging to an impl, return the
2473 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2474 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2475 let item = if def_id.krate != LOCAL_CRATE {
2476 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2477 Some(self.associated_item(def_id))
2482 self.opt_associated_item(def_id)
2486 Some(trait_item) => {
2487 match trait_item.container {
2488 TraitContainer(_) => None,
2489 ImplContainer(def_id) => Some(def_id),
2496 /// Construct a parameter environment suitable for static contexts or other contexts where there
2497 /// are no free type/lifetime parameters in scope.
2498 pub fn empty_parameter_environment(self) -> ParameterEnvironment<'tcx> {
2499 ty::ParameterEnvironment {
2500 free_substs: self.intern_substs(&[]),
2501 caller_bounds: Slice::empty(),
2502 implicit_region_bound: None,
2503 free_id_outlive: None,
2504 is_copy_cache: RefCell::new(FxHashMap()),
2505 is_sized_cache: RefCell::new(FxHashMap()),
2506 is_freeze_cache: RefCell::new(FxHashMap()),
2510 /// Constructs and returns a substitution that can be applied to move from
2511 /// the "outer" view of a type or method to the "inner" view.
2512 /// In general, this means converting from bound parameters to
2513 /// free parameters. Since we currently represent bound/free type
2514 /// parameters in the same way, this only has an effect on regions.
2515 pub fn construct_free_substs(self,
2517 free_id_outlive: Option<CodeExtent<'gcx>>)
2518 -> &'gcx Substs<'gcx> {
2520 let substs = Substs::for_item(self.global_tcx(), def_id, |def, _| {
2521 // map bound 'a => free 'a
2522 self.global_tcx().mk_region(ReFree(FreeRegion {
2523 scope: free_id_outlive,
2524 bound_region: def.to_bound_region()
2528 self.global_tcx().mk_param_from_def(def)
2531 debug!("construct_parameter_environment: {:?}", substs);
2535 /// See `ParameterEnvironment` struct def'n for details.
2536 /// If you were using `free_id: NodeId`, you might try `self.region_maps().item_extent(free_id)`
2537 /// for the `free_id_outlive` parameter. (But note that this is not always quite right.)
2538 pub fn construct_parameter_environment(self,
2541 free_id_outlive: Option<CodeExtent<'gcx>>)
2542 -> ParameterEnvironment<'gcx>
2545 // Construct the free substs.
2548 let free_substs = self.construct_free_substs(def_id, free_id_outlive);
2551 // Compute the bounds on Self and the type parameters.
2554 let tcx = self.global_tcx();
2555 let generic_predicates = tcx.predicates_of(def_id);
2556 let bounds = generic_predicates.instantiate(tcx, free_substs);
2557 let bounds = tcx.liberate_late_bound_regions(free_id_outlive, &ty::Binder(bounds));
2558 let predicates = bounds.predicates;
2560 // Finally, we have to normalize the bounds in the environment, in
2561 // case they contain any associated type projections. This process
2562 // can yield errors if the put in illegal associated types, like
2563 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2564 // report these errors right here; this doesn't actually feel
2565 // right to me, because constructing the environment feels like a
2566 // kind of a "idempotent" action, but I'm not sure where would be
2567 // a better place. In practice, we construct environments for
2568 // every fn once during type checking, and we'll abort if there
2569 // are any errors at that point, so after type checking you can be
2570 // sure that this will succeed without errors anyway.
2573 let unnormalized_env = ty::ParameterEnvironment {
2574 free_substs: free_substs,
2575 implicit_region_bound: free_id_outlive.map(|f| tcx.mk_region(ty::ReScope(f))),
2576 caller_bounds: tcx.intern_predicates(&predicates),
2577 free_id_outlive: free_id_outlive,
2578 is_copy_cache: RefCell::new(FxHashMap()),
2579 is_sized_cache: RefCell::new(FxHashMap()),
2580 is_freeze_cache: RefCell::new(FxHashMap()),
2583 let body_id = free_id_outlive.map(|f| f.node_id())
2584 .unwrap_or(DUMMY_NODE_ID);
2585 let cause = traits::ObligationCause::misc(span, body_id);
2586 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
2589 pub fn node_scope_region(self, id: NodeId) -> Region<'tcx> {
2590 self.mk_region(ty::ReScope(self.node_extent(id)))
2593 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2594 /// with the name of the crate containing the impl.
2595 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2596 if impl_did.is_local() {
2597 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2598 Ok(self.hir.span(node_id))
2600 Err(self.sess.cstore.crate_name(impl_did.krate))
2605 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2606 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2607 F: FnOnce(&[hir::Freevar]) -> T,
2609 match self.freevars.borrow().get(&fid) {
2611 Some(d) => f(&d[..])
2616 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
2619 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2620 let parent_id = tcx.hir.get_parent(id);
2621 let parent_def_id = tcx.hir.local_def_id(parent_id);
2622 let parent_item = tcx.hir.expect_item(parent_id);
2623 match parent_item.node {
2624 hir::ItemImpl(.., ref impl_item_refs) => {
2625 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2626 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2628 debug_assert_eq!(assoc_item.def_id, def_id);
2633 hir::ItemTrait(.., ref trait_item_refs) => {
2634 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2635 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2638 debug_assert_eq!(assoc_item.def_id, def_id);
2646 span_bug!(parent_item.span,
2647 "unexpected parent of trait or impl item or item not found: {:?}",
2651 /// Calculates the Sized-constraint.
2653 /// In fact, there are only a few options for the types in the constraint:
2654 /// - an obviously-unsized type
2655 /// - a type parameter or projection whose Sizedness can't be known
2656 /// - a tuple of type parameters or projections, if there are multiple
2658 /// - a TyError, if a type contained itself. The representability
2659 /// check should catch this case.
2660 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2662 -> &'tcx [Ty<'tcx>] {
2663 let def = tcx.adt_def(def_id);
2665 let result = tcx.intern_type_list(&def.variants.iter().flat_map(|v| {
2668 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2669 }).collect::<Vec<_>>());
2671 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2676 /// Calculates the dtorck constraint for a type.
2677 fn adt_dtorck_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2679 -> DtorckConstraint<'tcx> {
2680 let def = tcx.adt_def(def_id);
2681 let span = tcx.def_span(def_id);
2682 debug!("dtorck_constraint: {:?}", def);
2684 if def.is_phantom_data() {
2685 let result = DtorckConstraint {
2688 tcx.mk_param_from_def(&tcx.generics_of(def_id).types[0])
2691 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2695 let mut result = def.all_fields()
2696 .map(|field| tcx.type_of(field.did))
2697 .map(|fty| tcx.dtorck_constraint_for_ty(span, fty, 0, fty))
2698 .collect::<Result<DtorckConstraint, ErrorReported>>()
2699 .unwrap_or(DtorckConstraint::empty());
2700 result.outlives.extend(tcx.destructor_constraints(def));
2703 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2708 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2711 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2712 let item = tcx.hir.expect_item(id);
2713 let vec: Vec<_> = match item.node {
2714 hir::ItemTrait(.., ref trait_item_refs) => {
2715 trait_item_refs.iter()
2716 .map(|trait_item_ref| trait_item_ref.id)
2717 .map(|id| tcx.hir.local_def_id(id.node_id))
2720 hir::ItemImpl(.., ref impl_item_refs) => {
2721 impl_item_refs.iter()
2722 .map(|impl_item_ref| impl_item_ref.id)
2723 .map(|id| tcx.hir.local_def_id(id.node_id))
2726 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2731 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
2732 tcx.hir.span_if_local(def_id).unwrap()
2735 /// If the given def ID describes an item belonging to a trait,
2736 /// return the ID of the trait that the trait item belongs to.
2737 /// Otherwise, return `None`.
2738 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
2739 tcx.opt_associated_item(def_id)
2740 .and_then(|associated_item| {
2741 match associated_item.container {
2742 TraitContainer(def_id) => Some(def_id),
2743 ImplContainer(_) => None
2749 pub fn provide(providers: &mut ty::maps::Providers) {
2750 *providers = ty::maps::Providers {
2752 associated_item_def_ids,
2753 adt_sized_constraint,
2754 adt_dtorck_constraint,
2761 pub fn provide_extern(providers: &mut ty::maps::Providers) {
2762 *providers = ty::maps::Providers {
2763 adt_sized_constraint,
2764 adt_dtorck_constraint,
2770 /// A map for the local crate mapping each type to a vector of its
2771 /// inherent impls. This is not meant to be used outside of coherence;
2772 /// rather, you should request the vector for a specific type via
2773 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2774 /// (constructing this map requires touching the entire crate).
2775 #[derive(Clone, Debug)]
2776 pub struct CrateInherentImpls {
2777 pub inherent_impls: DefIdMap<Rc<Vec<DefId>>>,
2780 /// A set of constraints that need to be satisfied in order for
2781 /// a type to be valid for destruction.
2782 #[derive(Clone, Debug)]
2783 pub struct DtorckConstraint<'tcx> {
2784 /// Types that are required to be alive in order for this
2785 /// type to be valid for destruction.
2786 pub outlives: Vec<ty::subst::Kind<'tcx>>,
2787 /// Types that could not be resolved: projections and params.
2788 pub dtorck_types: Vec<Ty<'tcx>>,
2791 impl<'tcx> FromIterator<DtorckConstraint<'tcx>> for DtorckConstraint<'tcx>
2793 fn from_iter<I: IntoIterator<Item=DtorckConstraint<'tcx>>>(iter: I) -> Self {
2794 let mut result = Self::empty();
2796 for constraint in iter {
2797 result.outlives.extend(constraint.outlives);
2798 result.dtorck_types.extend(constraint.dtorck_types);
2806 impl<'tcx> DtorckConstraint<'tcx> {
2807 fn empty() -> DtorckConstraint<'tcx> {
2810 dtorck_types: vec![]
2814 fn dedup<'a>(&mut self) {
2815 let mut outlives = FxHashSet();
2816 let mut dtorck_types = FxHashSet();
2818 self.outlives.retain(|&val| outlives.replace(val).is_none());
2819 self.dtorck_types.retain(|&val| dtorck_types.replace(val).is_none());
2823 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord)]
2824 pub struct SymbolName {
2825 // FIXME: we don't rely on interning or equality here - better have
2826 // this be a `&'tcx str`.
2827 pub name: InternedString
2830 impl Deref for SymbolName {
2833 fn deref(&self) -> &str { &self.name }
2836 impl fmt::Display for SymbolName {
2837 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2838 fmt::Display::fmt(&self.name, fmt)