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 hir::{map as hir_map, FreevarMap, TraitMap};
19 use hir::def::{Def, CtorKind, ExportMap};
20 use hir::def_id::{CrateNum, DefId, DefIndex, CRATE_DEF_INDEX, LOCAL_CRATE};
21 use ich::StableHashingContext;
22 use middle::const_val::ConstVal;
23 use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
24 use middle::privacy::AccessLevels;
25 use middle::resolve_lifetime::ObjectLifetimeDefault;
26 use middle::region::CodeExtent;
30 use ty::subst::{Subst, Substs};
31 use ty::util::IntTypeExt;
32 use ty::walk::TypeWalker;
33 use util::common::ErrorReported;
34 use util::nodemap::{NodeSet, DefIdMap, FxHashMap, FxHashSet};
36 use serialize::{self, Encodable, Encoder};
37 use std::collections::BTreeMap;
40 use std::hash::{Hash, Hasher};
41 use std::iter::FromIterator;
45 use std::vec::IntoIter;
47 use syntax::ast::{self, DUMMY_NODE_ID, Name, Ident, NodeId};
49 use syntax::ext::hygiene::{Mark, SyntaxContext};
50 use syntax::symbol::{Symbol, InternedString};
51 use syntax_pos::{DUMMY_SP, Span};
52 use rustc_const_math::ConstInt;
54 use rustc_data_structures::accumulate_vec::IntoIter as AccIntoIter;
55 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
57 use rustc_data_structures::transitive_relation::TransitiveRelation;
61 pub use self::sty::{Binder, DebruijnIndex};
62 pub use self::sty::{FnSig, PolyFnSig};
63 pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
64 pub use self::sty::{ClosureSubsts, TypeAndMut};
65 pub use self::sty::{TraitRef, TypeVariants, PolyTraitRef};
66 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
67 pub use self::sty::{ExistentialProjection, PolyExistentialProjection};
68 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
69 pub use self::sty::RegionKind;
70 pub use self::sty::Issue32330;
71 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid, SkolemizedRegionVid};
72 pub use self::sty::BoundRegion::*;
73 pub use self::sty::InferTy::*;
74 pub use self::sty::RegionKind::*;
75 pub use self::sty::TypeVariants::*;
77 pub use self::context::{TyCtxt, GlobalArenas, tls};
78 pub use self::context::{Lift, TypeckTables};
80 pub use self::instance::{Instance, InstanceDef};
82 pub use self::trait_def::TraitDef;
84 pub use self::maps::queries;
91 pub mod inhabitedness;
108 mod structural_impls;
113 /// The complete set of all analyses described in this module. This is
114 /// produced by the driver and fed to trans and later passes.
116 /// NB: These contents are being migrated into queries using the
117 /// *on-demand* infrastructure.
119 pub struct CrateAnalysis {
120 pub access_levels: Rc<AccessLevels>,
121 pub reachable: Rc<NodeSet>,
123 pub glob_map: Option<hir::GlobMap>,
127 pub struct Resolutions {
128 pub freevars: FreevarMap,
129 pub trait_map: TraitMap,
130 pub maybe_unused_trait_imports: NodeSet,
131 pub export_map: ExportMap,
134 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
135 pub enum AssociatedItemContainer {
136 TraitContainer(DefId),
137 ImplContainer(DefId),
140 impl AssociatedItemContainer {
141 pub fn id(&self) -> DefId {
143 TraitContainer(id) => id,
144 ImplContainer(id) => id,
149 /// The "header" of an impl is everything outside the body: a Self type, a trait
150 /// ref (in the case of a trait impl), and a set of predicates (from the
151 /// bounds/where clauses).
152 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
153 pub struct ImplHeader<'tcx> {
154 pub impl_def_id: DefId,
155 pub self_ty: Ty<'tcx>,
156 pub trait_ref: Option<TraitRef<'tcx>>,
157 pub predicates: Vec<Predicate<'tcx>>,
160 #[derive(Copy, Clone, Debug)]
161 pub struct AssociatedItem {
164 pub kind: AssociatedKind,
166 pub defaultness: hir::Defaultness,
167 pub container: AssociatedItemContainer,
169 /// Whether this is a method with an explicit self
170 /// as its first argument, allowing method calls.
171 pub method_has_self_argument: bool,
174 #[derive(Copy, Clone, PartialEq, Eq, Debug, RustcEncodable, RustcDecodable)]
175 pub enum AssociatedKind {
181 impl AssociatedItem {
182 pub fn def(&self) -> Def {
184 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
185 AssociatedKind::Method => Def::Method(self.def_id),
186 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
190 /// Tests whether the associated item admits a non-trivial implementation
192 pub fn relevant_for_never<'tcx>(&self) -> bool {
194 AssociatedKind::Const => true,
195 AssociatedKind::Type => true,
196 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
197 AssociatedKind::Method => !self.method_has_self_argument,
201 pub fn signature<'a, 'tcx>(&self, tcx: &TyCtxt<'a, 'tcx, 'tcx>) -> String {
203 ty::AssociatedKind::Method => {
204 // We skip the binder here because the binder would deanonymize all
205 // late-bound regions, and we don't want method signatures to show up
206 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
207 // regions just fine, showing `fn(&MyType)`.
208 format!("{}", tcx.fn_sig(self.def_id).skip_binder())
210 ty::AssociatedKind::Type => format!("type {};", self.name.to_string()),
211 ty::AssociatedKind::Const => {
212 format!("const {}: {:?};", self.name.to_string(), tcx.type_of(self.def_id))
218 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
219 pub enum Visibility {
220 /// Visible everywhere (including in other crates).
222 /// Visible only in the given crate-local module.
224 /// Not visible anywhere in the local crate. This is the visibility of private external items.
228 pub trait DefIdTree: Copy {
229 fn parent(self, id: DefId) -> Option<DefId>;
231 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
232 if descendant.krate != ancestor.krate {
236 while descendant != ancestor {
237 match self.parent(descendant) {
238 Some(parent) => descendant = parent,
239 None => return false,
246 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
247 fn parent(self, id: DefId) -> Option<DefId> {
248 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
253 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt) -> Self {
255 hir::Public => Visibility::Public,
256 hir::Visibility::Crate => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
257 hir::Visibility::Restricted { ref path, .. } => match path.def {
258 // If there is no resolution, `resolve` will have already reported an error, so
259 // assume that the visibility is public to avoid reporting more privacy errors.
260 Def::Err => Visibility::Public,
261 def => Visibility::Restricted(def.def_id()),
264 Visibility::Restricted(tcx.hir.get_module_parent(id))
269 /// Returns true if an item with this visibility is accessible from the given block.
270 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
271 let restriction = match self {
272 // Public items are visible everywhere.
273 Visibility::Public => return true,
274 // Private items from other crates are visible nowhere.
275 Visibility::Invisible => return false,
276 // Restricted items are visible in an arbitrary local module.
277 Visibility::Restricted(other) if other.krate != module.krate => return false,
278 Visibility::Restricted(module) => module,
281 tree.is_descendant_of(module, restriction)
284 /// Returns true if this visibility is at least as accessible as the given visibility
285 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
286 let vis_restriction = match vis {
287 Visibility::Public => return self == Visibility::Public,
288 Visibility::Invisible => return true,
289 Visibility::Restricted(module) => module,
292 self.is_accessible_from(vis_restriction, tree)
296 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
298 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
299 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
300 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
301 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
304 /// The crate variances map is computed during typeck and contains the
305 /// variance of every item in the local crate. You should not use it
306 /// directly, because to do so will make your pass dependent on the
307 /// HIR of every item in the local crate. Instead, use
308 /// `tcx.variances_of()` to get the variance for a *particular*
310 pub struct CrateVariancesMap {
311 /// This relation tracks the dependencies between the variance of
312 /// various items. In particular, if `a < b`, then the variance of
313 /// `a` depends on the sources of `b`.
314 pub dependencies: TransitiveRelation<DefId>,
316 /// For each item with generics, maps to a vector of the variance
317 /// of its generics. If an item has no generics, it will have no
319 pub variances: FxHashMap<DefId, Rc<Vec<ty::Variance>>>,
321 /// An empty vector, useful for cloning.
322 pub empty_variance: Rc<Vec<ty::Variance>>,
326 /// `a.xform(b)` combines the variance of a context with the
327 /// variance of a type with the following meaning. If we are in a
328 /// context with variance `a`, and we encounter a type argument in
329 /// a position with variance `b`, then `a.xform(b)` is the new
330 /// variance with which the argument appears.
336 /// Here, the "ambient" variance starts as covariant. `*mut T` is
337 /// invariant with respect to `T`, so the variance in which the
338 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
339 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
340 /// respect to its type argument `T`, and hence the variance of
341 /// the `i32` here is `Invariant.xform(Covariant)`, which results
342 /// (again) in `Invariant`.
346 /// fn(*const Vec<i32>, *mut Vec<i32)
348 /// The ambient variance is covariant. A `fn` type is
349 /// contravariant with respect to its parameters, so the variance
350 /// within which both pointer types appear is
351 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
352 /// T` is covariant with respect to `T`, so the variance within
353 /// which the first `Vec<i32>` appears is
354 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
355 /// is true for its `i32` argument. In the `*mut T` case, the
356 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
357 /// and hence the outermost type is `Invariant` with respect to
358 /// `Vec<i32>` (and its `i32` argument).
360 /// Source: Figure 1 of "Taming the Wildcards:
361 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
362 pub fn xform(self, v: ty::Variance) -> ty::Variance {
364 // Figure 1, column 1.
365 (ty::Covariant, ty::Covariant) => ty::Covariant,
366 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
367 (ty::Covariant, ty::Invariant) => ty::Invariant,
368 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
370 // Figure 1, column 2.
371 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
372 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
373 (ty::Contravariant, ty::Invariant) => ty::Invariant,
374 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
376 // Figure 1, column 3.
377 (ty::Invariant, _) => ty::Invariant,
379 // Figure 1, column 4.
380 (ty::Bivariant, _) => ty::Bivariant,
385 // Contains information needed to resolve types and (in the future) look up
386 // the types of AST nodes.
387 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
388 pub struct CReaderCacheKey {
393 // Flags that we track on types. These flags are propagated upwards
394 // through the type during type construction, so that we can quickly
395 // check whether the type has various kinds of types in it without
396 // recursing over the type itself.
398 flags TypeFlags: u32 {
399 const HAS_PARAMS = 1 << 0,
400 const HAS_SELF = 1 << 1,
401 const HAS_TY_INFER = 1 << 2,
402 const HAS_RE_INFER = 1 << 3,
403 const HAS_RE_SKOL = 1 << 4,
404 const HAS_RE_EARLY_BOUND = 1 << 5,
405 const HAS_FREE_REGIONS = 1 << 6,
406 const HAS_TY_ERR = 1 << 7,
407 const HAS_PROJECTION = 1 << 8,
408 const HAS_TY_CLOSURE = 1 << 9,
410 // true if there are "names" of types and regions and so forth
411 // that are local to a particular fn
412 const HAS_LOCAL_NAMES = 1 << 10,
414 // Present if the type belongs in a local type context.
415 // Only set for TyInfer other than Fresh.
416 const KEEP_IN_LOCAL_TCX = 1 << 11,
418 // Is there a projection that does not involve a bound region?
419 // Currently we can't normalize projections w/ bound regions.
420 const HAS_NORMALIZABLE_PROJECTION = 1 << 12,
422 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
423 TypeFlags::HAS_SELF.bits |
424 TypeFlags::HAS_RE_EARLY_BOUND.bits,
426 // Flags representing the nominal content of a type,
427 // computed by FlagsComputation. If you add a new nominal
428 // flag, it should be added here too.
429 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
430 TypeFlags::HAS_SELF.bits |
431 TypeFlags::HAS_TY_INFER.bits |
432 TypeFlags::HAS_RE_INFER.bits |
433 TypeFlags::HAS_RE_SKOL.bits |
434 TypeFlags::HAS_RE_EARLY_BOUND.bits |
435 TypeFlags::HAS_FREE_REGIONS.bits |
436 TypeFlags::HAS_TY_ERR.bits |
437 TypeFlags::HAS_PROJECTION.bits |
438 TypeFlags::HAS_TY_CLOSURE.bits |
439 TypeFlags::HAS_LOCAL_NAMES.bits |
440 TypeFlags::KEEP_IN_LOCAL_TCX.bits,
444 pub struct TyS<'tcx> {
445 pub sty: TypeVariants<'tcx>,
446 pub flags: TypeFlags,
448 // the maximal depth of any bound regions appearing in this type.
452 impl<'tcx> PartialEq for TyS<'tcx> {
454 fn eq(&self, other: &TyS<'tcx>) -> bool {
455 // (self as *const _) == (other as *const _)
456 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
459 impl<'tcx> Eq for TyS<'tcx> {}
461 impl<'tcx> Hash for TyS<'tcx> {
462 fn hash<H: Hasher>(&self, s: &mut H) {
463 (self as *const TyS).hash(s)
467 impl<'tcx> TyS<'tcx> {
468 pub fn is_primitive_ty(&self) -> bool {
470 TypeVariants::TyBool |
471 TypeVariants::TyChar |
472 TypeVariants::TyInt(_) |
473 TypeVariants::TyUint(_) |
474 TypeVariants::TyFloat(_) |
475 TypeVariants::TyInfer(InferTy::IntVar(_)) |
476 TypeVariants::TyInfer(InferTy::FloatVar(_)) |
477 TypeVariants::TyInfer(InferTy::FreshIntTy(_)) |
478 TypeVariants::TyInfer(InferTy::FreshFloatTy(_)) => true,
479 TypeVariants::TyRef(_, x) => x.ty.is_primitive_ty(),
484 pub fn is_suggestable(&self) -> bool {
486 TypeVariants::TyAnon(..) |
487 TypeVariants::TyFnDef(..) |
488 TypeVariants::TyFnPtr(..) |
489 TypeVariants::TyDynamic(..) |
490 TypeVariants::TyClosure(..) |
491 TypeVariants::TyProjection(..) => false,
497 impl<'a, 'gcx, 'tcx> HashStable<StableHashingContext<'a, 'gcx, 'tcx>> for ty::TyS<'tcx> {
498 fn hash_stable<W: StableHasherResult>(&self,
499 hcx: &mut StableHashingContext<'a, 'gcx, 'tcx>,
500 hasher: &mut StableHasher<W>) {
504 // The other fields just provide fast access to information that is
505 // also contained in `sty`, so no need to hash them.
510 sty.hash_stable(hcx, hasher);
514 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
516 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
517 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
519 /// A wrapper for slices with the additional invariant
520 /// that the slice is interned and no other slice with
521 /// the same contents can exist in the same context.
522 /// This means we can use pointer + length for both
523 /// equality comparisons and hashing.
524 #[derive(Debug, RustcEncodable)]
525 pub struct Slice<T>([T]);
527 impl<T> PartialEq for Slice<T> {
529 fn eq(&self, other: &Slice<T>) -> bool {
530 (&self.0 as *const [T]) == (&other.0 as *const [T])
533 impl<T> Eq for Slice<T> {}
535 impl<T> Hash for Slice<T> {
536 fn hash<H: Hasher>(&self, s: &mut H) {
537 (self.as_ptr(), self.len()).hash(s)
541 impl<T> Deref for Slice<T> {
543 fn deref(&self) -> &[T] {
548 impl<'a, T> IntoIterator for &'a Slice<T> {
550 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
551 fn into_iter(self) -> Self::IntoIter {
556 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {}
559 pub fn empty<'a>() -> &'a Slice<T> {
561 mem::transmute(slice::from_raw_parts(0x1 as *const T, 0))
566 /// Upvars do not get their own node-id. Instead, we use the pair of
567 /// the original var id (that is, the root variable that is referenced
568 /// by the upvar) and the id of the closure expression.
569 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
572 pub closure_expr_id: NodeId,
575 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
576 pub enum BorrowKind {
577 /// Data must be immutable and is aliasable.
580 /// Data must be immutable but not aliasable. This kind of borrow
581 /// cannot currently be expressed by the user and is used only in
582 /// implicit closure bindings. It is needed when the closure
583 /// is borrowing or mutating a mutable referent, e.g.:
585 /// let x: &mut isize = ...;
586 /// let y = || *x += 5;
588 /// If we were to try to translate this closure into a more explicit
589 /// form, we'd encounter an error with the code as written:
591 /// struct Env { x: & &mut isize }
592 /// let x: &mut isize = ...;
593 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
594 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
596 /// This is then illegal because you cannot mutate a `&mut` found
597 /// in an aliasable location. To solve, you'd have to translate with
598 /// an `&mut` borrow:
600 /// struct Env { x: & &mut isize }
601 /// let x: &mut isize = ...;
602 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
603 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
605 /// Now the assignment to `**env.x` is legal, but creating a
606 /// mutable pointer to `x` is not because `x` is not mutable. We
607 /// could fix this by declaring `x` as `let mut x`. This is ok in
608 /// user code, if awkward, but extra weird for closures, since the
609 /// borrow is hidden.
611 /// So we introduce a "unique imm" borrow -- the referent is
612 /// immutable, but not aliasable. This solves the problem. For
613 /// simplicity, we don't give users the way to express this
614 /// borrow, it's just used when translating closures.
617 /// Data is mutable and not aliasable.
621 /// Information describing the capture of an upvar. This is computed
622 /// during `typeck`, specifically by `regionck`.
623 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
624 pub enum UpvarCapture<'tcx> {
625 /// Upvar is captured by value. This is always true when the
626 /// closure is labeled `move`, but can also be true in other cases
627 /// depending on inference.
630 /// Upvar is captured by reference.
631 ByRef(UpvarBorrow<'tcx>),
634 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
635 pub struct UpvarBorrow<'tcx> {
636 /// The kind of borrow: by-ref upvars have access to shared
637 /// immutable borrows, which are not part of the normal language
639 pub kind: BorrowKind,
641 /// Region of the resulting reference.
642 pub region: ty::Region<'tcx>,
645 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
647 #[derive(Copy, Clone)]
648 pub struct ClosureUpvar<'tcx> {
654 #[derive(Clone, Copy, PartialEq)]
655 pub enum IntVarValue {
657 UintType(ast::UintTy),
660 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
661 pub struct TypeParameterDef {
665 pub has_default: bool,
666 pub object_lifetime_default: ObjectLifetimeDefault,
668 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
669 /// on generic parameter `T`, asserts data behind the parameter
670 /// `T` won't be accessed during the parent type's `Drop` impl.
671 pub pure_wrt_drop: bool,
674 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
675 pub struct RegionParameterDef {
679 pub issue_32330: Option<ty::Issue32330>,
681 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
682 /// on generic parameter `'a`, asserts data of lifetime `'a`
683 /// won't be accessed during the parent type's `Drop` impl.
684 pub pure_wrt_drop: bool,
687 impl RegionParameterDef {
688 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
689 ty::EarlyBoundRegion {
696 pub fn to_bound_region(&self) -> ty::BoundRegion {
697 self.to_early_bound_region_data().to_bound_region()
701 impl ty::EarlyBoundRegion {
702 pub fn to_bound_region(&self) -> ty::BoundRegion {
703 ty::BoundRegion::BrNamed(self.def_id, self.name)
707 /// Information about the formal type/lifetime parameters associated
708 /// with an item or method. Analogous to hir::Generics.
709 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
710 pub struct Generics {
711 pub parent: Option<DefId>,
712 pub parent_regions: u32,
713 pub parent_types: u32,
714 pub regions: Vec<RegionParameterDef>,
715 pub types: Vec<TypeParameterDef>,
717 /// Reverse map to each `TypeParameterDef`'s `index` field, from
718 /// `def_id.index` (`def_id.krate` is the same as the item's).
719 pub type_param_to_index: BTreeMap<DefIndex, u32>,
725 pub fn parent_count(&self) -> usize {
726 self.parent_regions as usize + self.parent_types as usize
729 pub fn own_count(&self) -> usize {
730 self.regions.len() + self.types.len()
733 pub fn count(&self) -> usize {
734 self.parent_count() + self.own_count()
737 pub fn region_param(&self, param: &EarlyBoundRegion) -> &RegionParameterDef {
738 assert_eq!(self.parent_count(), 0);
739 &self.regions[param.index as usize - self.has_self as usize]
742 pub fn type_param(&self, param: &ParamTy) -> &TypeParameterDef {
743 assert_eq!(self.parent_count(), 0);
744 &self.types[param.idx as usize - self.has_self as usize - self.regions.len()]
748 /// Bounds on generics.
749 #[derive(Clone, Default)]
750 pub struct GenericPredicates<'tcx> {
751 pub parent: Option<DefId>,
752 pub predicates: Vec<Predicate<'tcx>>,
755 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
756 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
758 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
759 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
760 -> InstantiatedPredicates<'tcx> {
761 let mut instantiated = InstantiatedPredicates::empty();
762 self.instantiate_into(tcx, &mut instantiated, substs);
765 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
766 -> InstantiatedPredicates<'tcx> {
767 InstantiatedPredicates {
768 predicates: self.predicates.subst(tcx, substs)
772 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
773 instantiated: &mut InstantiatedPredicates<'tcx>,
774 substs: &Substs<'tcx>) {
775 if let Some(def_id) = self.parent {
776 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
778 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
781 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
782 -> InstantiatedPredicates<'tcx> {
783 let mut instantiated = InstantiatedPredicates::empty();
784 self.instantiate_identity_into(tcx, &mut instantiated);
788 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
789 instantiated: &mut InstantiatedPredicates<'tcx>) {
790 if let Some(def_id) = self.parent {
791 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
793 instantiated.predicates.extend(&self.predicates)
796 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
797 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
798 -> InstantiatedPredicates<'tcx>
800 assert_eq!(self.parent, None);
801 InstantiatedPredicates {
802 predicates: self.predicates.iter().map(|pred| {
803 pred.subst_supertrait(tcx, poly_trait_ref)
809 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
810 pub enum Predicate<'tcx> {
811 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
812 /// the `Self` type of the trait reference and `A`, `B`, and `C`
813 /// would be the type parameters.
814 Trait(PolyTraitPredicate<'tcx>),
816 /// where `T1 == T2`.
817 Equate(PolyEquatePredicate<'tcx>),
820 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
823 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
825 /// where <T as TraitRef>::Name == X, approximately.
826 /// See `ProjectionPredicate` struct for details.
827 Projection(PolyProjectionPredicate<'tcx>),
830 WellFormed(Ty<'tcx>),
832 /// trait must be object-safe
835 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
836 /// for some substitutions `...` and T being a closure type.
837 /// Satisfied (or refuted) once we know the closure's kind.
838 ClosureKind(DefId, ClosureKind),
841 Subtype(PolySubtypePredicate<'tcx>),
844 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
845 /// Performs a substitution suitable for going from a
846 /// poly-trait-ref to supertraits that must hold if that
847 /// poly-trait-ref holds. This is slightly different from a normal
848 /// substitution in terms of what happens with bound regions. See
849 /// lengthy comment below for details.
850 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
851 trait_ref: &ty::PolyTraitRef<'tcx>)
852 -> ty::Predicate<'tcx>
854 // The interaction between HRTB and supertraits is not entirely
855 // obvious. Let me walk you (and myself) through an example.
857 // Let's start with an easy case. Consider two traits:
859 // trait Foo<'a> : Bar<'a,'a> { }
860 // trait Bar<'b,'c> { }
862 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
863 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
864 // knew that `Foo<'x>` (for any 'x) then we also know that
865 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
866 // normal substitution.
868 // In terms of why this is sound, the idea is that whenever there
869 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
870 // holds. So if there is an impl of `T:Foo<'a>` that applies to
871 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
874 // Another example to be careful of is this:
876 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
877 // trait Bar1<'b,'c> { }
879 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
880 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
881 // reason is similar to the previous example: any impl of
882 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
883 // basically we would want to collapse the bound lifetimes from
884 // the input (`trait_ref`) and the supertraits.
886 // To achieve this in practice is fairly straightforward. Let's
887 // consider the more complicated scenario:
889 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
890 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
891 // where both `'x` and `'b` would have a DB index of 1.
892 // The substitution from the input trait-ref is therefore going to be
893 // `'a => 'x` (where `'x` has a DB index of 1).
894 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
895 // early-bound parameter and `'b' is a late-bound parameter with a
897 // - If we replace `'a` with `'x` from the input, it too will have
898 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
899 // just as we wanted.
901 // There is only one catch. If we just apply the substitution `'a
902 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
903 // adjust the DB index because we substituting into a binder (it
904 // tries to be so smart...) resulting in `for<'x> for<'b>
905 // Bar1<'x,'b>` (we have no syntax for this, so use your
906 // imagination). Basically the 'x will have DB index of 2 and 'b
907 // will have DB index of 1. Not quite what we want. So we apply
908 // the substitution to the *contents* of the trait reference,
909 // rather than the trait reference itself (put another way, the
910 // substitution code expects equal binding levels in the values
911 // from the substitution and the value being substituted into, and
912 // this trick achieves that).
914 let substs = &trait_ref.0.substs;
916 Predicate::Trait(ty::Binder(ref data)) =>
917 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
918 Predicate::Equate(ty::Binder(ref data)) =>
919 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
920 Predicate::Subtype(ty::Binder(ref data)) =>
921 Predicate::Subtype(ty::Binder(data.subst(tcx, substs))),
922 Predicate::RegionOutlives(ty::Binder(ref data)) =>
923 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
924 Predicate::TypeOutlives(ty::Binder(ref data)) =>
925 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
926 Predicate::Projection(ty::Binder(ref data)) =>
927 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
928 Predicate::WellFormed(data) =>
929 Predicate::WellFormed(data.subst(tcx, substs)),
930 Predicate::ObjectSafe(trait_def_id) =>
931 Predicate::ObjectSafe(trait_def_id),
932 Predicate::ClosureKind(closure_def_id, kind) =>
933 Predicate::ClosureKind(closure_def_id, kind),
938 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
939 pub struct TraitPredicate<'tcx> {
940 pub trait_ref: TraitRef<'tcx>
942 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
944 impl<'tcx> TraitPredicate<'tcx> {
945 pub fn def_id(&self) -> DefId {
946 self.trait_ref.def_id
949 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
950 self.trait_ref.input_types()
953 pub fn self_ty(&self) -> Ty<'tcx> {
954 self.trait_ref.self_ty()
958 impl<'tcx> PolyTraitPredicate<'tcx> {
959 pub fn def_id(&self) -> DefId {
960 // ok to skip binder since trait def-id does not care about regions
965 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
966 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
967 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
969 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
970 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
971 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
972 pub type PolyRegionOutlivesPredicate<'tcx> = PolyOutlivesPredicate<ty::Region<'tcx>,
974 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
976 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
977 pub struct SubtypePredicate<'tcx> {
978 pub a_is_expected: bool,
982 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
984 /// This kind of predicate has no *direct* correspondent in the
985 /// syntax, but it roughly corresponds to the syntactic forms:
987 /// 1. `T : TraitRef<..., Item=Type>`
988 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
990 /// In particular, form #1 is "desugared" to the combination of a
991 /// normal trait predicate (`T : TraitRef<...>`) and one of these
992 /// predicates. Form #2 is a broader form in that it also permits
993 /// equality between arbitrary types. Processing an instance of Form
994 /// #2 eventually yields one of these `ProjectionPredicate`
995 /// instances to normalize the LHS.
996 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
997 pub struct ProjectionPredicate<'tcx> {
998 pub projection_ty: ProjectionTy<'tcx>,
1002 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1004 impl<'tcx> PolyProjectionPredicate<'tcx> {
1005 pub fn to_poly_trait_ref(&self, tcx: TyCtxt) -> PolyTraitRef<'tcx> {
1006 // Note: unlike with TraitRef::to_poly_trait_ref(),
1007 // self.0.trait_ref is permitted to have escaping regions.
1008 // This is because here `self` has a `Binder` and so does our
1009 // return value, so we are preserving the number of binding
1011 ty::Binder(self.0.projection_ty.trait_ref(tcx))
1015 pub trait ToPolyTraitRef<'tcx> {
1016 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1019 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1020 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1021 assert!(!self.has_escaping_regions());
1022 ty::Binder(self.clone())
1026 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1027 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1028 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1032 pub trait ToPredicate<'tcx> {
1033 fn to_predicate(&self) -> Predicate<'tcx>;
1036 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1037 fn to_predicate(&self) -> Predicate<'tcx> {
1038 // we're about to add a binder, so let's check that we don't
1039 // accidentally capture anything, or else that might be some
1040 // weird debruijn accounting.
1041 assert!(!self.has_escaping_regions());
1043 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
1044 trait_ref: self.clone()
1049 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1050 fn to_predicate(&self) -> Predicate<'tcx> {
1051 ty::Predicate::Trait(self.to_poly_trait_predicate())
1055 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
1056 fn to_predicate(&self) -> Predicate<'tcx> {
1057 Predicate::Equate(self.clone())
1061 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1062 fn to_predicate(&self) -> Predicate<'tcx> {
1063 Predicate::RegionOutlives(self.clone())
1067 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1068 fn to_predicate(&self) -> Predicate<'tcx> {
1069 Predicate::TypeOutlives(self.clone())
1073 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1074 fn to_predicate(&self) -> Predicate<'tcx> {
1075 Predicate::Projection(self.clone())
1079 impl<'tcx> Predicate<'tcx> {
1080 /// Iterates over the types in this predicate. Note that in all
1081 /// cases this is skipping over a binder, so late-bound regions
1082 /// with depth 0 are bound by the predicate.
1083 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1084 let vec: Vec<_> = match *self {
1085 ty::Predicate::Trait(ref data) => {
1086 data.skip_binder().input_types().collect()
1088 ty::Predicate::Equate(ty::Binder(ref data)) => {
1089 vec![data.0, data.1]
1091 ty::Predicate::Subtype(ty::Binder(SubtypePredicate { a, b, a_is_expected: _ })) => {
1094 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
1097 ty::Predicate::RegionOutlives(..) => {
1100 ty::Predicate::Projection(ref data) => {
1101 data.0.projection_ty.substs.types().chain(Some(data.0.ty)).collect()
1103 ty::Predicate::WellFormed(data) => {
1106 ty::Predicate::ObjectSafe(_trait_def_id) => {
1109 ty::Predicate::ClosureKind(_closure_def_id, _kind) => {
1114 // The only reason to collect into a vector here is that I was
1115 // too lazy to make the full (somewhat complicated) iterator
1116 // type that would be needed here. But I wanted this fn to
1117 // return an iterator conceptually, rather than a `Vec`, so as
1118 // to be closer to `Ty::walk`.
1122 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1124 Predicate::Trait(ref t) => {
1125 Some(t.to_poly_trait_ref())
1127 Predicate::Projection(..) |
1128 Predicate::Equate(..) |
1129 Predicate::Subtype(..) |
1130 Predicate::RegionOutlives(..) |
1131 Predicate::WellFormed(..) |
1132 Predicate::ObjectSafe(..) |
1133 Predicate::ClosureKind(..) |
1134 Predicate::TypeOutlives(..) => {
1141 /// Represents the bounds declared on a particular set of type
1142 /// parameters. Should eventually be generalized into a flag list of
1143 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1144 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1145 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1146 /// the `GenericPredicates` are expressed in terms of the bound type
1147 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1148 /// represented a set of bounds for some particular instantiation,
1149 /// meaning that the generic parameters have been substituted with
1154 /// struct Foo<T,U:Bar<T>> { ... }
1156 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1157 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1158 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1159 /// [usize:Bar<isize>]]`.
1161 pub struct InstantiatedPredicates<'tcx> {
1162 pub predicates: Vec<Predicate<'tcx>>,
1165 impl<'tcx> InstantiatedPredicates<'tcx> {
1166 pub fn empty() -> InstantiatedPredicates<'tcx> {
1167 InstantiatedPredicates { predicates: vec![] }
1170 pub fn is_empty(&self) -> bool {
1171 self.predicates.is_empty()
1175 /// When type checking, we use the `ParamEnv` to track
1176 /// details about the set of where-clauses that are in scope at this
1177 /// particular point.
1178 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1179 pub struct ParamEnv<'tcx> {
1180 /// Obligations that the caller must satisfy. This is basically
1181 /// the set of bounds on the in-scope type parameters, translated
1182 /// into Obligations, and elaborated and normalized.
1183 pub caller_bounds: &'tcx Slice<ty::Predicate<'tcx>>,
1185 /// Typically, this is `Reveal::UserFacing`, but during trans we
1186 /// want `Reveal::All` -- note that this is always paired with an
1187 /// empty environment. To get that, use `ParamEnv::reveal()`.
1188 pub reveal: traits::Reveal,
1191 impl<'tcx> ParamEnv<'tcx> {
1192 /// Creates a suitable environment in which to perform trait
1193 /// queries on the given value. This will either be `self` *or*
1194 /// the empty environment, depending on whether `value` references
1195 /// type parameters that are in scope. (If it doesn't, then any
1196 /// judgements should be completely independent of the context,
1197 /// and hence we can safely use the empty environment so as to
1198 /// enable more sharing across functions.)
1200 /// NB: This is a mildly dubious thing to do, in that a function
1201 /// (or other environment) might have wacky where-clauses like
1202 /// `where Box<u32>: Copy`, which are clearly never
1203 /// satisfiable. The code will at present ignore these,
1204 /// effectively, when type-checking the body of said
1205 /// function. This preserves existing behavior in any
1206 /// case. --nmatsakis
1207 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1208 assert!(!value.needs_infer());
1209 if value.has_param_types() || value.has_self_ty() {
1216 param_env: ParamEnv::empty(self.reveal),
1223 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1224 pub struct ParamEnvAnd<'tcx, T> {
1225 pub param_env: ParamEnv<'tcx>,
1229 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1230 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1231 (self.param_env, self.value)
1235 #[derive(Copy, Clone, Debug)]
1236 pub struct Destructor {
1237 /// The def-id of the destructor method
1242 flags AdtFlags: u32 {
1243 const NO_ADT_FLAGS = 0,
1244 const IS_ENUM = 1 << 0,
1245 const IS_PHANTOM_DATA = 1 << 1,
1246 const IS_FUNDAMENTAL = 1 << 2,
1247 const IS_UNION = 1 << 3,
1248 const IS_BOX = 1 << 4,
1253 pub struct VariantDef {
1254 /// The variant's DefId. If this is a tuple-like struct,
1255 /// this is the DefId of the struct's ctor.
1257 pub name: Name, // struct's name if this is a struct
1258 pub discr: VariantDiscr,
1259 pub fields: Vec<FieldDef>,
1260 pub ctor_kind: CtorKind,
1263 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1264 pub enum VariantDiscr {
1265 /// Explicit value for this variant, i.e. `X = 123`.
1266 /// The `DefId` corresponds to the embedded constant.
1269 /// The previous variant's discriminant plus one.
1270 /// For efficiency reasons, the distance from the
1271 /// last `Explicit` discriminant is being stored,
1272 /// or `0` for the first variant, if it has none.
1277 pub struct FieldDef {
1280 pub vis: Visibility,
1283 /// The definition of an abstract data type - a struct or enum.
1285 /// These are all interned (by intern_adt_def) into the adt_defs
1289 pub variants: Vec<VariantDef>,
1291 pub repr: ReprOptions,
1294 impl PartialEq for AdtDef {
1295 // AdtDef are always interned and this is part of TyS equality
1297 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1300 impl Eq for AdtDef {}
1302 impl Hash for AdtDef {
1304 fn hash<H: Hasher>(&self, s: &mut H) {
1305 (self as *const AdtDef).hash(s)
1309 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1310 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1315 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1318 impl<'a, 'gcx, 'tcx> HashStable<StableHashingContext<'a, 'gcx, 'tcx>> for AdtDef {
1319 fn hash_stable<W: StableHasherResult>(&self,
1320 hcx: &mut StableHashingContext<'a, 'gcx, 'tcx>,
1321 hasher: &mut StableHasher<W>) {
1329 did.hash_stable(hcx, hasher);
1330 variants.hash_stable(hcx, hasher);
1331 flags.hash_stable(hcx, hasher);
1332 repr.hash_stable(hcx, hasher);
1336 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1337 pub enum AdtKind { Struct, Union, Enum }
1340 #[derive(RustcEncodable, RustcDecodable, Default)]
1341 flags ReprFlags: u8 {
1342 const IS_C = 1 << 0,
1343 const IS_PACKED = 1 << 1,
1344 const IS_SIMD = 1 << 2,
1345 // Internal only for now. If true, don't reorder fields.
1346 const IS_LINEAR = 1 << 3,
1348 // Any of these flags being set prevent field reordering optimisation.
1349 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1350 ReprFlags::IS_PACKED.bits |
1351 ReprFlags::IS_SIMD.bits |
1352 ReprFlags::IS_LINEAR.bits,
1356 impl_stable_hash_for!(struct ReprFlags {
1362 /// Represents the repr options provided by the user,
1363 #[derive(Copy, Clone, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1364 pub struct ReprOptions {
1365 pub int: Option<attr::IntType>,
1367 pub flags: ReprFlags,
1370 impl_stable_hash_for!(struct ReprOptions {
1377 pub fn new(tcx: TyCtxt, did: DefId) -> ReprOptions {
1378 let mut flags = ReprFlags::empty();
1379 let mut size = None;
1380 let mut max_align = 0;
1381 for attr in tcx.get_attrs(did).iter() {
1382 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1383 flags.insert(match r {
1384 attr::ReprExtern => ReprFlags::IS_C,
1385 attr::ReprPacked => ReprFlags::IS_PACKED,
1386 attr::ReprSimd => ReprFlags::IS_SIMD,
1387 attr::ReprInt(i) => {
1391 attr::ReprAlign(align) => {
1392 max_align = cmp::max(align, max_align);
1399 // FIXME(eddyb) This is deprecated and should be removed.
1400 if tcx.has_attr(did, "simd") {
1401 flags.insert(ReprFlags::IS_SIMD);
1404 // This is here instead of layout because the choice must make it into metadata.
1405 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1406 flags.insert(ReprFlags::IS_LINEAR);
1408 ReprOptions { int: size, align: max_align, flags: flags }
1412 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1414 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1416 pub fn packed(&self) -> bool { self.flags.contains(ReprFlags::IS_PACKED) }
1418 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1420 pub fn discr_type(&self) -> attr::IntType {
1421 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Is))
1424 /// Returns true if this `#[repr()]` should inhabit "smart enum
1425 /// layout" optimizations, such as representing `Foo<&T>` as a
1427 pub fn inhibit_enum_layout_opt(&self) -> bool {
1428 self.c() || self.int.is_some()
1432 impl<'a, 'gcx, 'tcx> AdtDef {
1436 variants: Vec<VariantDef>,
1437 repr: ReprOptions) -> Self {
1438 let mut flags = AdtFlags::NO_ADT_FLAGS;
1439 let attrs = tcx.get_attrs(did);
1440 if attr::contains_name(&attrs, "fundamental") {
1441 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1443 if Some(did) == tcx.lang_items.phantom_data() {
1444 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1446 if Some(did) == tcx.lang_items.owned_box() {
1447 flags = flags | AdtFlags::IS_BOX;
1450 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
1451 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
1452 AdtKind::Struct => {}
1463 pub fn is_struct(&self) -> bool {
1464 !self.is_union() && !self.is_enum()
1468 pub fn is_union(&self) -> bool {
1469 self.flags.intersects(AdtFlags::IS_UNION)
1473 pub fn is_enum(&self) -> bool {
1474 self.flags.intersects(AdtFlags::IS_ENUM)
1477 /// Returns the kind of the ADT - Struct or Enum.
1479 pub fn adt_kind(&self) -> AdtKind {
1482 } else if self.is_union() {
1489 pub fn descr(&self) -> &'static str {
1490 match self.adt_kind() {
1491 AdtKind::Struct => "struct",
1492 AdtKind::Union => "union",
1493 AdtKind::Enum => "enum",
1497 pub fn variant_descr(&self) -> &'static str {
1498 match self.adt_kind() {
1499 AdtKind::Struct => "struct",
1500 AdtKind::Union => "union",
1501 AdtKind::Enum => "variant",
1505 /// Returns whether this type is #[fundamental] for the purposes
1506 /// of coherence checking.
1508 pub fn is_fundamental(&self) -> bool {
1509 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
1512 /// Returns true if this is PhantomData<T>.
1514 pub fn is_phantom_data(&self) -> bool {
1515 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
1518 /// Returns true if this is Box<T>.
1520 pub fn is_box(&self) -> bool {
1521 self.flags.intersects(AdtFlags::IS_BOX)
1524 /// Returns whether this type has a destructor.
1525 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
1526 self.destructor(tcx).is_some()
1529 /// Asserts this is a struct and returns the struct's unique
1531 pub fn struct_variant(&self) -> &VariantDef {
1532 assert!(!self.is_enum());
1537 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
1538 tcx.predicates_of(self.did)
1541 /// Returns an iterator over all fields contained
1544 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
1545 self.variants.iter().flat_map(|v| v.fields.iter())
1549 pub fn is_univariant(&self) -> bool {
1550 self.variants.len() == 1
1553 pub fn is_payloadfree(&self) -> bool {
1554 !self.variants.is_empty() &&
1555 self.variants.iter().all(|v| v.fields.is_empty())
1558 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
1561 .find(|v| v.did == vid)
1562 .expect("variant_with_id: unknown variant")
1565 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1568 .position(|v| v.did == vid)
1569 .expect("variant_index_with_id: unknown variant")
1572 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
1574 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
1575 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
1576 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.struct_variant(),
1577 _ => bug!("unexpected def {:?} in variant_of_def", def)
1582 pub fn discriminants(&'a self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1583 -> impl Iterator<Item=ConstInt> + 'a {
1584 let repr_type = self.repr.discr_type();
1585 let initial = repr_type.initial_discriminant(tcx.global_tcx());
1586 let mut prev_discr = None::<ConstInt>;
1587 self.variants.iter().map(move |v| {
1588 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr());
1589 if let VariantDiscr::Explicit(expr_did) = v.discr {
1590 let substs = Substs::empty();
1591 match tcx.const_eval((expr_did, substs)) {
1592 Ok(ConstVal::Integral(v)) => {
1596 if !expr_did.is_local() {
1597 span_bug!(tcx.def_span(expr_did),
1598 "variant discriminant evaluation succeeded \
1599 in its crate but failed locally: {:?}", err);
1604 prev_discr = Some(discr);
1610 /// Compute the discriminant value used by a specific variant.
1611 /// Unlike `discriminants`, this is (amortized) constant-time,
1612 /// only doing at most one query for evaluating an explicit
1613 /// discriminant (the last one before the requested variant),
1614 /// assuming there are no constant-evaluation errors there.
1615 pub fn discriminant_for_variant(&self,
1616 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1617 variant_index: usize)
1619 let repr_type = self.repr.discr_type();
1620 let mut explicit_value = repr_type.initial_discriminant(tcx.global_tcx());
1621 let mut explicit_index = variant_index;
1623 match self.variants[explicit_index].discr {
1624 ty::VariantDiscr::Relative(0) => break,
1625 ty::VariantDiscr::Relative(distance) => {
1626 explicit_index -= distance;
1628 ty::VariantDiscr::Explicit(expr_did) => {
1629 let substs = Substs::empty();
1630 match tcx.const_eval((expr_did, substs)) {
1631 Ok(ConstVal::Integral(v)) => {
1636 if !expr_did.is_local() {
1637 span_bug!(tcx.def_span(expr_did),
1638 "variant discriminant evaluation succeeded \
1639 in its crate but failed locally: {:?}", err);
1641 if explicit_index == 0 {
1644 explicit_index -= 1;
1650 let discr = explicit_value.to_u128_unchecked()
1651 .wrapping_add((variant_index - explicit_index) as u128);
1653 attr::UnsignedInt(ty) => {
1654 ConstInt::new_unsigned_truncating(discr, ty,
1655 tcx.sess.target.uint_type)
1657 attr::SignedInt(ty) => {
1658 ConstInt::new_signed_truncating(discr as i128, ty,
1659 tcx.sess.target.int_type)
1664 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
1665 tcx.adt_destructor(self.did)
1668 /// Returns a list of types such that `Self: Sized` if and only
1669 /// if that type is Sized, or `TyErr` if this type is recursive.
1671 /// Oddly enough, checking that the sized-constraint is Sized is
1672 /// actually more expressive than checking all members:
1673 /// the Sized trait is inductive, so an associated type that references
1674 /// Self would prevent its containing ADT from being Sized.
1676 /// Due to normalization being eager, this applies even if
1677 /// the associated type is behind a pointer, e.g. issue #31299.
1678 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
1679 match queries::adt_sized_constraint::try_get(tcx, DUMMY_SP, self.did) {
1682 debug!("adt_sized_constraint: {:?} is recursive", self);
1683 // This should be reported as an error by `check_representable`.
1685 // Consider the type as Sized in the meanwhile to avoid
1687 tcx.intern_type_list(&[tcx.types.err])
1692 fn sized_constraint_for_ty(&self,
1693 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1696 let result = match ty.sty {
1697 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
1698 TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
1699 TyArray(..) | TyClosure(..) | TyNever => {
1703 TyStr | TyDynamic(..) | TySlice(_) | TyError => {
1704 // these are never sized - return the target type
1708 TyTuple(ref tys, _) => {
1711 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
1715 TyAdt(adt, substs) => {
1717 let adt_tys = adt.sized_constraint(tcx);
1718 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
1721 .map(|ty| ty.subst(tcx, substs))
1722 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
1726 TyProjection(..) | TyAnon(..) => {
1727 // must calculate explicitly.
1728 // FIXME: consider special-casing always-Sized projections
1733 // perf hack: if there is a `T: Sized` bound, then
1734 // we know that `T` is Sized and do not need to check
1737 let sized_trait = match tcx.lang_items.sized_trait() {
1739 _ => return vec![ty]
1741 let sized_predicate = Binder(TraitRef {
1742 def_id: sized_trait,
1743 substs: tcx.mk_substs_trait(ty, &[])
1745 let predicates = tcx.predicates_of(self.did).predicates;
1746 if predicates.into_iter().any(|p| p == sized_predicate) {
1754 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
1758 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
1763 impl<'a, 'gcx, 'tcx> VariantDef {
1765 pub fn find_field_named(&self, name: ast::Name) -> Option<&FieldDef> {
1766 self.index_of_field_named(name).map(|index| &self.fields[index])
1769 pub fn index_of_field_named(&self, name: ast::Name) -> Option<usize> {
1770 if let Some(index) = self.fields.iter().position(|f| f.name == name) {
1773 let mut ident = name.to_ident();
1774 while ident.ctxt != SyntaxContext::empty() {
1775 ident.ctxt.remove_mark();
1776 if let Some(field) = self.fields.iter().position(|f| f.name.to_ident() == ident) {
1784 pub fn field_named(&self, name: ast::Name) -> &FieldDef {
1785 self.find_field_named(name).unwrap()
1789 impl<'a, 'gcx, 'tcx> FieldDef {
1790 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1791 tcx.type_of(self.did).subst(tcx, subst)
1795 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1796 pub enum ClosureKind {
1797 // Warning: Ordering is significant here! The ordering is chosen
1798 // because the trait Fn is a subtrait of FnMut and so in turn, and
1799 // hence we order it so that Fn < FnMut < FnOnce.
1805 impl<'a, 'tcx> ClosureKind {
1806 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
1808 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
1809 ClosureKind::FnMut => {
1810 tcx.require_lang_item(FnMutTraitLangItem)
1812 ClosureKind::FnOnce => {
1813 tcx.require_lang_item(FnOnceTraitLangItem)
1818 /// True if this a type that impls this closure kind
1819 /// must also implement `other`.
1820 pub fn extends(self, other: ty::ClosureKind) -> bool {
1821 match (self, other) {
1822 (ClosureKind::Fn, ClosureKind::Fn) => true,
1823 (ClosureKind::Fn, ClosureKind::FnMut) => true,
1824 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
1825 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
1826 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
1827 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
1833 impl<'tcx> TyS<'tcx> {
1834 /// Iterator that walks `self` and any types reachable from
1835 /// `self`, in depth-first order. Note that just walks the types
1836 /// that appear in `self`, it does not descend into the fields of
1837 /// structs or variants. For example:
1840 /// isize => { isize }
1841 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
1842 /// [isize] => { [isize], isize }
1844 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
1845 TypeWalker::new(self)
1848 /// Iterator that walks the immediate children of `self`. Hence
1849 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
1850 /// (but not `i32`, like `walk`).
1851 pub fn walk_shallow(&'tcx self) -> AccIntoIter<walk::TypeWalkerArray<'tcx>> {
1852 walk::walk_shallow(self)
1855 /// Walks `ty` and any types appearing within `ty`, invoking the
1856 /// callback `f` on each type. If the callback returns false, then the
1857 /// children of the current type are ignored.
1859 /// Note: prefer `ty.walk()` where possible.
1860 pub fn maybe_walk<F>(&'tcx self, mut f: F)
1861 where F : FnMut(Ty<'tcx>) -> bool
1863 let mut walker = self.walk();
1864 while let Some(ty) = walker.next() {
1866 walker.skip_current_subtree();
1872 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1873 pub enum LvaluePreference {
1878 impl LvaluePreference {
1879 pub fn from_mutbl(m: hir::Mutability) -> Self {
1881 hir::MutMutable => PreferMutLvalue,
1882 hir::MutImmutable => NoPreference,
1888 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
1890 hir::MutMutable => MutBorrow,
1891 hir::MutImmutable => ImmBorrow,
1895 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
1896 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
1897 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
1899 pub fn to_mutbl_lossy(self) -> hir::Mutability {
1901 MutBorrow => hir::MutMutable,
1902 ImmBorrow => hir::MutImmutable,
1904 // We have no type corresponding to a unique imm borrow, so
1905 // use `&mut`. It gives all the capabilities of an `&uniq`
1906 // and hence is a safe "over approximation".
1907 UniqueImmBorrow => hir::MutMutable,
1911 pub fn to_user_str(&self) -> &'static str {
1913 MutBorrow => "mutable",
1914 ImmBorrow => "immutable",
1915 UniqueImmBorrow => "uniquely immutable",
1920 #[derive(Debug, Clone)]
1921 pub enum Attributes<'gcx> {
1922 Owned(Rc<[ast::Attribute]>),
1923 Borrowed(&'gcx [ast::Attribute])
1926 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
1927 type Target = [ast::Attribute];
1929 fn deref(&self) -> &[ast::Attribute] {
1931 &Attributes::Owned(ref data) => &data,
1932 &Attributes::Borrowed(data) => data
1937 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
1938 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
1939 self.typeck_tables_of(self.hir.body_owner_def_id(body))
1942 /// Returns an iterator of the def-ids for all body-owners in this
1943 /// crate. If you would prefer to iterate over the bodies
1944 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
1945 pub fn body_owners(self) -> impl Iterator<Item = DefId> + 'a {
1949 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
1952 pub fn expr_span(self, id: NodeId) -> Span {
1953 match self.hir.find(id) {
1954 Some(hir_map::NodeExpr(e)) => {
1958 bug!("Node id {} is not an expr: {:?}", id, f);
1961 bug!("Node id {} is not present in the node map", id);
1966 pub fn local_var_name_str(self, id: NodeId) -> InternedString {
1967 match self.hir.find(id) {
1968 Some(hir_map::NodeLocal(pat)) => {
1970 hir::PatKind::Binding(_, _, ref path1, _) => path1.node.as_str(),
1972 bug!("Variable id {} maps to {:?}, not local", id, pat);
1976 r => bug!("Variable id {} maps to {:?}, not local", id, r),
1980 pub fn expr_is_lval(self, expr: &hir::Expr) -> bool {
1982 hir::ExprPath(hir::QPath::Resolved(_, ref path)) => {
1984 Def::Local(..) | Def::Upvar(..) | Def::Static(..) | Def::Err => true,
1989 hir::ExprType(ref e, _) => {
1990 self.expr_is_lval(e)
1993 hir::ExprUnary(hir::UnDeref, _) |
1994 hir::ExprField(..) |
1995 hir::ExprTupField(..) |
1996 hir::ExprIndex(..) => {
2000 // Partially qualified paths in expressions can only legally
2001 // refer to associated items which are always rvalues.
2002 hir::ExprPath(hir::QPath::TypeRelative(..)) |
2005 hir::ExprMethodCall(..) |
2006 hir::ExprStruct(..) |
2009 hir::ExprMatch(..) |
2010 hir::ExprClosure(..) |
2011 hir::ExprBlock(..) |
2012 hir::ExprRepeat(..) |
2013 hir::ExprArray(..) |
2014 hir::ExprBreak(..) |
2015 hir::ExprAgain(..) |
2017 hir::ExprWhile(..) |
2019 hir::ExprAssign(..) |
2020 hir::ExprInlineAsm(..) |
2021 hir::ExprAssignOp(..) |
2023 hir::ExprUnary(..) |
2025 hir::ExprAddrOf(..) |
2026 hir::ExprBinary(..) |
2027 hir::ExprCast(..) => {
2033 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2034 self.associated_items(id)
2035 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2039 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2040 self.associated_items(did).any(|item| {
2041 item.relevant_for_never()
2045 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2046 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2047 match self.hir.get(node_id) {
2048 hir_map::NodeTraitItem(_) | hir_map::NodeImplItem(_) => true,
2052 match self.describe_def(def_id).expect("no def for def-id") {
2053 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2058 if is_associated_item {
2059 Some(self.associated_item(def_id))
2065 fn associated_item_from_trait_item_ref(self,
2066 parent_def_id: DefId,
2067 parent_vis: &hir::Visibility,
2068 trait_item_ref: &hir::TraitItemRef)
2070 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2071 let (kind, has_self) = match trait_item_ref.kind {
2072 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2073 hir::AssociatedItemKind::Method { has_self } => {
2074 (ty::AssociatedKind::Method, has_self)
2076 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2080 name: trait_item_ref.name,
2082 // Visibility of trait items is inherited from their traits.
2083 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2084 defaultness: trait_item_ref.defaultness,
2086 container: TraitContainer(parent_def_id),
2087 method_has_self_argument: has_self
2091 fn associated_item_from_impl_item_ref(self,
2092 parent_def_id: DefId,
2093 impl_item_ref: &hir::ImplItemRef)
2095 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2096 let (kind, has_self) = match impl_item_ref.kind {
2097 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2098 hir::AssociatedItemKind::Method { has_self } => {
2099 (ty::AssociatedKind::Method, has_self)
2101 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2104 ty::AssociatedItem {
2105 name: impl_item_ref.name,
2107 // Visibility of trait impl items doesn't matter.
2108 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2109 defaultness: impl_item_ref.defaultness,
2111 container: ImplContainer(parent_def_id),
2112 method_has_self_argument: has_self
2116 #[inline] // FIXME(#35870) Avoid closures being unexported due to impl Trait.
2117 pub fn associated_items(self, def_id: DefId)
2118 -> impl Iterator<Item = ty::AssociatedItem> + 'a {
2119 let def_ids = self.associated_item_def_ids(def_id);
2120 (0..def_ids.len()).map(move |i| self.associated_item(def_ids[i]))
2123 /// Returns true if the impls are the same polarity and are implementing
2124 /// a trait which contains no items
2125 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2126 if !self.sess.features.borrow().overlapping_marker_traits {
2129 let trait1_is_empty = self.impl_trait_ref(def_id1)
2130 .map_or(false, |trait_ref| {
2131 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2133 let trait2_is_empty = self.impl_trait_ref(def_id2)
2134 .map_or(false, |trait_ref| {
2135 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2137 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2142 // Returns `ty::VariantDef` if `def` refers to a struct,
2143 // or variant or their constructors, panics otherwise.
2144 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2146 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2147 let enum_did = self.parent_def_id(did).unwrap();
2148 self.adt_def(enum_did).variant_with_id(did)
2150 Def::Struct(did) | Def::Union(did) => {
2151 self.adt_def(did).struct_variant()
2153 Def::StructCtor(ctor_did, ..) => {
2154 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2155 self.adt_def(did).struct_variant()
2157 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2161 pub fn def_key(self, id: DefId) -> hir_map::DefKey {
2163 self.hir.def_key(id)
2165 self.sess.cstore.def_key(id)
2169 /// Convert a `DefId` into its fully expanded `DefPath` (every
2170 /// `DefId` is really just an interned def-path).
2172 /// Note that if `id` is not local to this crate, the result will
2173 /// be a non-local `DefPath`.
2174 pub fn def_path(self, id: DefId) -> hir_map::DefPath {
2176 self.hir.def_path(id)
2178 self.sess.cstore.def_path(id)
2183 pub fn def_path_hash(self, def_id: DefId) -> hir_map::DefPathHash {
2184 if def_id.is_local() {
2185 self.hir.definitions().def_path_hash(def_id.index)
2187 self.sess.cstore.def_path_hash(def_id)
2191 pub fn item_name(self, id: DefId) -> ast::Name {
2192 if let Some(id) = self.hir.as_local_node_id(id) {
2194 } else if id.index == CRATE_DEF_INDEX {
2195 self.sess.cstore.original_crate_name(id.krate)
2197 let def_key = self.sess.cstore.def_key(id);
2198 // The name of a StructCtor is that of its struct parent.
2199 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2200 self.item_name(DefId {
2202 index: def_key.parent.unwrap()
2205 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2206 bug!("item_name: no name for {:?}", self.def_path(id));
2212 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2213 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2217 ty::InstanceDef::Item(did) => {
2218 self.optimized_mir(did)
2220 ty::InstanceDef::Intrinsic(..) |
2221 ty::InstanceDef::FnPtrShim(..) |
2222 ty::InstanceDef::Virtual(..) |
2223 ty::InstanceDef::ClosureOnceShim { .. } |
2224 ty::InstanceDef::DropGlue(..) => {
2225 self.mir_shims(instance)
2230 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2231 /// Returns None if there is no MIR for the DefId
2232 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2233 if self.is_mir_available(did) {
2234 Some(self.optimized_mir(did))
2240 /// Get the attributes of a definition.
2241 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2242 if let Some(id) = self.hir.as_local_node_id(did) {
2243 Attributes::Borrowed(self.hir.attrs(id))
2245 Attributes::Owned(self.item_attrs(did))
2249 /// Determine whether an item is annotated with an attribute
2250 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2251 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2254 pub fn trait_has_default_impl(self, trait_def_id: DefId) -> bool {
2255 self.trait_def(trait_def_id).has_default_impl
2258 /// Given the def_id of an impl, return the def_id of the trait it implements.
2259 /// If it implements no trait, return `None`.
2260 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2261 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2264 /// If the given def ID describes a method belonging to an impl, return the
2265 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2266 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2267 let item = if def_id.krate != LOCAL_CRATE {
2268 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2269 Some(self.associated_item(def_id))
2274 self.opt_associated_item(def_id)
2278 Some(trait_item) => {
2279 match trait_item.container {
2280 TraitContainer(_) => None,
2281 ImplContainer(def_id) => Some(def_id),
2288 pub fn node_scope_region(self, id: NodeId) -> Region<'tcx> {
2289 self.mk_region(ty::ReScope(CodeExtent::Misc(id)))
2292 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2293 /// with the name of the crate containing the impl.
2294 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2295 if impl_did.is_local() {
2296 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2297 Ok(self.hir.span(node_id))
2299 Err(self.sess.cstore.crate_name(impl_did.krate))
2303 pub fn adjust(self, name: Name, scope: DefId, block: NodeId) -> (Ident, DefId) {
2304 self.adjust_ident(name.to_ident(), scope, block)
2307 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
2308 let expansion = match scope.krate {
2309 LOCAL_CRATE => self.hir.definitions().expansion(scope.index),
2312 let scope = match ident.ctxt.adjust(expansion) {
2313 Some(macro_def) => self.hir.definitions().macro_def_scope(macro_def),
2314 None => self.hir.get_module_parent(block),
2320 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2321 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2322 F: FnOnce(&[hir::Freevar]) -> T,
2324 match self.freevars.borrow().get(&fid) {
2326 Some(d) => f(&d[..])
2331 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
2334 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2335 let parent_id = tcx.hir.get_parent(id);
2336 let parent_def_id = tcx.hir.local_def_id(parent_id);
2337 let parent_item = tcx.hir.expect_item(parent_id);
2338 match parent_item.node {
2339 hir::ItemImpl(.., ref impl_item_refs) => {
2340 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2341 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2343 debug_assert_eq!(assoc_item.def_id, def_id);
2348 hir::ItemTrait(.., ref trait_item_refs) => {
2349 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2350 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2353 debug_assert_eq!(assoc_item.def_id, def_id);
2361 span_bug!(parent_item.span,
2362 "unexpected parent of trait or impl item or item not found: {:?}",
2366 /// Calculates the Sized-constraint.
2368 /// In fact, there are only a few options for the types in the constraint:
2369 /// - an obviously-unsized type
2370 /// - a type parameter or projection whose Sizedness can't be known
2371 /// - a tuple of type parameters or projections, if there are multiple
2373 /// - a TyError, if a type contained itself. The representability
2374 /// check should catch this case.
2375 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2377 -> &'tcx [Ty<'tcx>] {
2378 let def = tcx.adt_def(def_id);
2380 let result = tcx.intern_type_list(&def.variants.iter().flat_map(|v| {
2383 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2384 }).collect::<Vec<_>>());
2386 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2391 /// Calculates the dtorck constraint for a type.
2392 fn adt_dtorck_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2394 -> DtorckConstraint<'tcx> {
2395 let def = tcx.adt_def(def_id);
2396 let span = tcx.def_span(def_id);
2397 debug!("dtorck_constraint: {:?}", def);
2399 if def.is_phantom_data() {
2400 let result = DtorckConstraint {
2403 tcx.mk_param_from_def(&tcx.generics_of(def_id).types[0])
2406 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2410 let mut result = def.all_fields()
2411 .map(|field| tcx.type_of(field.did))
2412 .map(|fty| tcx.dtorck_constraint_for_ty(span, fty, 0, fty))
2413 .collect::<Result<DtorckConstraint, ErrorReported>>()
2414 .unwrap_or(DtorckConstraint::empty());
2415 result.outlives.extend(tcx.destructor_constraints(def));
2418 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2423 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2426 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2427 let item = tcx.hir.expect_item(id);
2428 let vec: Vec<_> = match item.node {
2429 hir::ItemTrait(.., ref trait_item_refs) => {
2430 trait_item_refs.iter()
2431 .map(|trait_item_ref| trait_item_ref.id)
2432 .map(|id| tcx.hir.local_def_id(id.node_id))
2435 hir::ItemImpl(.., ref impl_item_refs) => {
2436 impl_item_refs.iter()
2437 .map(|impl_item_ref| impl_item_ref.id)
2438 .map(|id| tcx.hir.local_def_id(id.node_id))
2441 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2446 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
2447 tcx.hir.span_if_local(def_id).unwrap()
2450 /// If the given def ID describes an item belonging to a trait,
2451 /// return the ID of the trait that the trait item belongs to.
2452 /// Otherwise, return `None`.
2453 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
2454 tcx.opt_associated_item(def_id)
2455 .and_then(|associated_item| {
2456 match associated_item.container {
2457 TraitContainer(def_id) => Some(def_id),
2458 ImplContainer(_) => None
2463 /// See `ParamEnv` struct def'n for details.
2464 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2467 // Compute the bounds on Self and the type parameters.
2469 let bounds = tcx.predicates_of(def_id).instantiate_identity(tcx);
2470 let predicates = bounds.predicates;
2472 // Finally, we have to normalize the bounds in the environment, in
2473 // case they contain any associated type projections. This process
2474 // can yield errors if the put in illegal associated types, like
2475 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2476 // report these errors right here; this doesn't actually feel
2477 // right to me, because constructing the environment feels like a
2478 // kind of a "idempotent" action, but I'm not sure where would be
2479 // a better place. In practice, we construct environments for
2480 // every fn once during type checking, and we'll abort if there
2481 // are any errors at that point, so after type checking you can be
2482 // sure that this will succeed without errors anyway.
2484 let unnormalized_env = ty::ParamEnv::new(tcx.intern_predicates(&predicates),
2485 traits::Reveal::UserFacing);
2487 let body_id = tcx.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
2488 tcx.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_id)
2490 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
2491 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
2494 pub fn provide(providers: &mut ty::maps::Providers) {
2495 util::provide(providers);
2496 *providers = ty::maps::Providers {
2498 associated_item_def_ids,
2499 adt_sized_constraint,
2500 adt_dtorck_constraint,
2504 trait_impls_of: trait_def::trait_impls_of_provider,
2505 relevant_trait_impls_for: trait_def::relevant_trait_impls_provider,
2510 pub fn provide_extern(providers: &mut ty::maps::Providers) {
2511 *providers = ty::maps::Providers {
2512 adt_sized_constraint,
2513 adt_dtorck_constraint,
2514 trait_impls_of: trait_def::trait_impls_of_provider,
2515 relevant_trait_impls_for: trait_def::relevant_trait_impls_provider,
2522 /// A map for the local crate mapping each type to a vector of its
2523 /// inherent impls. This is not meant to be used outside of coherence;
2524 /// rather, you should request the vector for a specific type via
2525 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2526 /// (constructing this map requires touching the entire crate).
2527 #[derive(Clone, Debug)]
2528 pub struct CrateInherentImpls {
2529 pub inherent_impls: DefIdMap<Rc<Vec<DefId>>>,
2532 /// A set of constraints that need to be satisfied in order for
2533 /// a type to be valid for destruction.
2534 #[derive(Clone, Debug)]
2535 pub struct DtorckConstraint<'tcx> {
2536 /// Types that are required to be alive in order for this
2537 /// type to be valid for destruction.
2538 pub outlives: Vec<ty::subst::Kind<'tcx>>,
2539 /// Types that could not be resolved: projections and params.
2540 pub dtorck_types: Vec<Ty<'tcx>>,
2543 impl<'tcx> FromIterator<DtorckConstraint<'tcx>> for DtorckConstraint<'tcx>
2545 fn from_iter<I: IntoIterator<Item=DtorckConstraint<'tcx>>>(iter: I) -> Self {
2546 let mut result = Self::empty();
2548 for constraint in iter {
2549 result.outlives.extend(constraint.outlives);
2550 result.dtorck_types.extend(constraint.dtorck_types);
2558 impl<'tcx> DtorckConstraint<'tcx> {
2559 fn empty() -> DtorckConstraint<'tcx> {
2562 dtorck_types: vec![]
2566 fn dedup<'a>(&mut self) {
2567 let mut outlives = FxHashSet();
2568 let mut dtorck_types = FxHashSet();
2570 self.outlives.retain(|&val| outlives.replace(val).is_none());
2571 self.dtorck_types.retain(|&val| dtorck_types.replace(val).is_none());
2575 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord)]
2576 pub struct SymbolName {
2577 // FIXME: we don't rely on interning or equality here - better have
2578 // this be a `&'tcx str`.
2579 pub name: InternedString
2582 impl Deref for SymbolName {
2585 fn deref(&self) -> &str { &self.name }
2588 impl fmt::Display for SymbolName {
2589 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2590 fmt::Display::fmt(&self.name, fmt)