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;
27 use mir::GeneratorLayout;
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, GenSig, PolyFnSig, PolyGenSig};
63 pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
64 pub use self::sty::{ClosureSubsts, GeneratorInterior, 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::{TyVid, IntVid, FloatVid, RegionVid, SkolemizedRegionVid};
71 pub use self::sty::BoundRegion::*;
72 pub use self::sty::InferTy::*;
73 pub use self::sty::RegionKind::*;
74 pub use self::sty::TypeVariants::*;
76 pub use self::binding::BindingMode;
77 pub use self::binding::BindingMode::*;
79 pub use self::context::{TyCtxt, GlobalArenas, tls, keep_local};
80 pub use self::context::{Lift, TypeckTables};
82 pub use self::instance::{Instance, InstanceDef};
84 pub use self::trait_def::TraitDef;
86 pub use self::maps::queries;
94 pub mod inhabitedness;
111 mod structural_impls;
116 /// The complete set of all analyses described in this module. This is
117 /// produced by the driver and fed to trans and later passes.
119 /// NB: These contents are being migrated into queries using the
120 /// *on-demand* infrastructure.
122 pub struct CrateAnalysis {
123 pub access_levels: Rc<AccessLevels>,
124 pub reachable: Rc<NodeSet>,
126 pub glob_map: Option<hir::GlobMap>,
130 pub struct Resolutions {
131 pub freevars: FreevarMap,
132 pub trait_map: TraitMap,
133 pub maybe_unused_trait_imports: NodeSet,
134 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
135 pub export_map: ExportMap,
138 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
139 pub enum AssociatedItemContainer {
140 TraitContainer(DefId),
141 ImplContainer(DefId),
144 impl AssociatedItemContainer {
145 pub fn id(&self) -> DefId {
147 TraitContainer(id) => id,
148 ImplContainer(id) => id,
153 /// The "header" of an impl is everything outside the body: a Self type, a trait
154 /// ref (in the case of a trait impl), and a set of predicates (from the
155 /// bounds/where clauses).
156 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
157 pub struct ImplHeader<'tcx> {
158 pub impl_def_id: DefId,
159 pub self_ty: Ty<'tcx>,
160 pub trait_ref: Option<TraitRef<'tcx>>,
161 pub predicates: Vec<Predicate<'tcx>>,
164 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
165 pub struct AssociatedItem {
168 pub kind: AssociatedKind,
170 pub defaultness: hir::Defaultness,
171 pub container: AssociatedItemContainer,
173 /// Whether this is a method with an explicit self
174 /// as its first argument, allowing method calls.
175 pub method_has_self_argument: bool,
178 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash, RustcEncodable, RustcDecodable)]
179 pub enum AssociatedKind {
185 impl AssociatedItem {
186 pub fn def(&self) -> Def {
188 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
189 AssociatedKind::Method => Def::Method(self.def_id),
190 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
194 /// Tests whether the associated item admits a non-trivial implementation
196 pub fn relevant_for_never<'tcx>(&self) -> bool {
198 AssociatedKind::Const => true,
199 AssociatedKind::Type => true,
200 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
201 AssociatedKind::Method => !self.method_has_self_argument,
205 pub fn signature<'a, 'tcx>(&self, tcx: &TyCtxt<'a, 'tcx, 'tcx>) -> String {
207 ty::AssociatedKind::Method => {
208 // We skip the binder here because the binder would deanonymize all
209 // late-bound regions, and we don't want method signatures to show up
210 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
211 // regions just fine, showing `fn(&MyType)`.
212 format!("{}", tcx.fn_sig(self.def_id).skip_binder())
214 ty::AssociatedKind::Type => format!("type {};", self.name.to_string()),
215 ty::AssociatedKind::Const => {
216 format!("const {}: {:?};", self.name.to_string(), tcx.type_of(self.def_id))
222 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
223 pub enum Visibility {
224 /// Visible everywhere (including in other crates).
226 /// Visible only in the given crate-local module.
228 /// Not visible anywhere in the local crate. This is the visibility of private external items.
232 pub trait DefIdTree: Copy {
233 fn parent(self, id: DefId) -> Option<DefId>;
235 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
236 if descendant.krate != ancestor.krate {
240 while descendant != ancestor {
241 match self.parent(descendant) {
242 Some(parent) => descendant = parent,
243 None => return false,
250 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
251 fn parent(self, id: DefId) -> Option<DefId> {
252 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
257 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt) -> Self {
259 hir::Public => Visibility::Public,
260 hir::Visibility::Crate => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
261 hir::Visibility::Restricted { ref path, .. } => match path.def {
262 // If there is no resolution, `resolve` will have already reported an error, so
263 // assume that the visibility is public to avoid reporting more privacy errors.
264 Def::Err => Visibility::Public,
265 def => Visibility::Restricted(def.def_id()),
268 Visibility::Restricted(tcx.hir.get_module_parent(id))
273 /// Returns true if an item with this visibility is accessible from the given block.
274 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
275 let restriction = match self {
276 // Public items are visible everywhere.
277 Visibility::Public => return true,
278 // Private items from other crates are visible nowhere.
279 Visibility::Invisible => return false,
280 // Restricted items are visible in an arbitrary local module.
281 Visibility::Restricted(other) if other.krate != module.krate => return false,
282 Visibility::Restricted(module) => module,
285 tree.is_descendant_of(module, restriction)
288 /// Returns true if this visibility is at least as accessible as the given visibility
289 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
290 let vis_restriction = match vis {
291 Visibility::Public => return self == Visibility::Public,
292 Visibility::Invisible => return true,
293 Visibility::Restricted(module) => module,
296 self.is_accessible_from(vis_restriction, tree)
300 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
302 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
303 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
304 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
305 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
308 /// The crate variances map is computed during typeck and contains the
309 /// variance of every item in the local crate. You should not use it
310 /// directly, because to do so will make your pass dependent on the
311 /// HIR of every item in the local crate. Instead, use
312 /// `tcx.variances_of()` to get the variance for a *particular*
314 pub struct CrateVariancesMap {
315 /// This relation tracks the dependencies between the variance of
316 /// various items. In particular, if `a < b`, then the variance of
317 /// `a` depends on the sources of `b`.
318 pub dependencies: TransitiveRelation<DefId>,
320 /// For each item with generics, maps to a vector of the variance
321 /// of its generics. If an item has no generics, it will have no
323 pub variances: FxHashMap<DefId, Rc<Vec<ty::Variance>>>,
325 /// An empty vector, useful for cloning.
326 pub empty_variance: Rc<Vec<ty::Variance>>,
330 /// `a.xform(b)` combines the variance of a context with the
331 /// variance of a type with the following meaning. If we are in a
332 /// context with variance `a`, and we encounter a type argument in
333 /// a position with variance `b`, then `a.xform(b)` is the new
334 /// variance with which the argument appears.
340 /// Here, the "ambient" variance starts as covariant. `*mut T` is
341 /// invariant with respect to `T`, so the variance in which the
342 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
343 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
344 /// respect to its type argument `T`, and hence the variance of
345 /// the `i32` here is `Invariant.xform(Covariant)`, which results
346 /// (again) in `Invariant`.
350 /// fn(*const Vec<i32>, *mut Vec<i32)
352 /// The ambient variance is covariant. A `fn` type is
353 /// contravariant with respect to its parameters, so the variance
354 /// within which both pointer types appear is
355 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
356 /// T` is covariant with respect to `T`, so the variance within
357 /// which the first `Vec<i32>` appears is
358 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
359 /// is true for its `i32` argument. In the `*mut T` case, the
360 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
361 /// and hence the outermost type is `Invariant` with respect to
362 /// `Vec<i32>` (and its `i32` argument).
364 /// Source: Figure 1 of "Taming the Wildcards:
365 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
366 pub fn xform(self, v: ty::Variance) -> ty::Variance {
368 // Figure 1, column 1.
369 (ty::Covariant, ty::Covariant) => ty::Covariant,
370 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
371 (ty::Covariant, ty::Invariant) => ty::Invariant,
372 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
374 // Figure 1, column 2.
375 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
376 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
377 (ty::Contravariant, ty::Invariant) => ty::Invariant,
378 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
380 // Figure 1, column 3.
381 (ty::Invariant, _) => ty::Invariant,
383 // Figure 1, column 4.
384 (ty::Bivariant, _) => ty::Bivariant,
389 // Contains information needed to resolve types and (in the future) look up
390 // the types of AST nodes.
391 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
392 pub struct CReaderCacheKey {
397 // Flags that we track on types. These flags are propagated upwards
398 // through the type during type construction, so that we can quickly
399 // check whether the type has various kinds of types in it without
400 // recursing over the type itself.
402 flags TypeFlags: u32 {
403 const HAS_PARAMS = 1 << 0,
404 const HAS_SELF = 1 << 1,
405 const HAS_TY_INFER = 1 << 2,
406 const HAS_RE_INFER = 1 << 3,
407 const HAS_RE_SKOL = 1 << 4,
408 const HAS_RE_EARLY_BOUND = 1 << 5,
409 const HAS_FREE_REGIONS = 1 << 6,
410 const HAS_TY_ERR = 1 << 7,
411 const HAS_PROJECTION = 1 << 8,
413 // FIXME: Rename this to the actual property since it's used for generators too
414 const HAS_TY_CLOSURE = 1 << 9,
416 // true if there are "names" of types and regions and so forth
417 // that are local to a particular fn
418 const HAS_LOCAL_NAMES = 1 << 10,
420 // Present if the type belongs in a local type context.
421 // Only set for TyInfer other than Fresh.
422 const KEEP_IN_LOCAL_TCX = 1 << 11,
424 // Is there a projection that does not involve a bound region?
425 // Currently we can't normalize projections w/ bound regions.
426 const HAS_NORMALIZABLE_PROJECTION = 1 << 12,
428 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
429 TypeFlags::HAS_SELF.bits |
430 TypeFlags::HAS_RE_EARLY_BOUND.bits,
432 // Flags representing the nominal content of a type,
433 // computed by FlagsComputation. If you add a new nominal
434 // flag, it should be added here too.
435 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
436 TypeFlags::HAS_SELF.bits |
437 TypeFlags::HAS_TY_INFER.bits |
438 TypeFlags::HAS_RE_INFER.bits |
439 TypeFlags::HAS_RE_SKOL.bits |
440 TypeFlags::HAS_RE_EARLY_BOUND.bits |
441 TypeFlags::HAS_FREE_REGIONS.bits |
442 TypeFlags::HAS_TY_ERR.bits |
443 TypeFlags::HAS_PROJECTION.bits |
444 TypeFlags::HAS_TY_CLOSURE.bits |
445 TypeFlags::HAS_LOCAL_NAMES.bits |
446 TypeFlags::KEEP_IN_LOCAL_TCX.bits,
450 pub struct TyS<'tcx> {
451 pub sty: TypeVariants<'tcx>,
452 pub flags: TypeFlags,
454 // the maximal depth of any bound regions appearing in this type.
458 impl<'tcx> PartialEq for TyS<'tcx> {
460 fn eq(&self, other: &TyS<'tcx>) -> bool {
461 // (self as *const _) == (other as *const _)
462 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
465 impl<'tcx> Eq for TyS<'tcx> {}
467 impl<'tcx> Hash for TyS<'tcx> {
468 fn hash<H: Hasher>(&self, s: &mut H) {
469 (self as *const TyS).hash(s)
473 impl<'tcx> TyS<'tcx> {
474 pub fn is_primitive_ty(&self) -> bool {
476 TypeVariants::TyBool |
477 TypeVariants::TyChar |
478 TypeVariants::TyInt(_) |
479 TypeVariants::TyUint(_) |
480 TypeVariants::TyFloat(_) |
481 TypeVariants::TyInfer(InferTy::IntVar(_)) |
482 TypeVariants::TyInfer(InferTy::FloatVar(_)) |
483 TypeVariants::TyInfer(InferTy::FreshIntTy(_)) |
484 TypeVariants::TyInfer(InferTy::FreshFloatTy(_)) => true,
485 TypeVariants::TyRef(_, x) => x.ty.is_primitive_ty(),
490 pub fn is_suggestable(&self) -> bool {
492 TypeVariants::TyAnon(..) |
493 TypeVariants::TyFnDef(..) |
494 TypeVariants::TyFnPtr(..) |
495 TypeVariants::TyDynamic(..) |
496 TypeVariants::TyClosure(..) |
497 TypeVariants::TyInfer(..) |
498 TypeVariants::TyProjection(..) => false,
504 impl<'a, 'gcx, 'tcx> HashStable<StableHashingContext<'a, 'gcx, 'tcx>> for ty::TyS<'gcx> {
505 fn hash_stable<W: StableHasherResult>(&self,
506 hcx: &mut StableHashingContext<'a, 'gcx, 'tcx>,
507 hasher: &mut StableHasher<W>) {
511 // The other fields just provide fast access to information that is
512 // also contained in `sty`, so no need to hash them.
517 sty.hash_stable(hcx, hasher);
521 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
523 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
524 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
526 /// A wrapper for slices with the additional invariant
527 /// that the slice is interned and no other slice with
528 /// the same contents can exist in the same context.
529 /// This means we can use pointer + length for both
530 /// equality comparisons and hashing.
531 #[derive(Debug, RustcEncodable)]
532 pub struct Slice<T>([T]);
534 impl<T> PartialEq for Slice<T> {
536 fn eq(&self, other: &Slice<T>) -> bool {
537 (&self.0 as *const [T]) == (&other.0 as *const [T])
540 impl<T> Eq for Slice<T> {}
542 impl<T> Hash for Slice<T> {
543 fn hash<H: Hasher>(&self, s: &mut H) {
544 (self.as_ptr(), self.len()).hash(s)
548 impl<T> Deref for Slice<T> {
550 fn deref(&self) -> &[T] {
555 impl<'a, T> IntoIterator for &'a Slice<T> {
557 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
558 fn into_iter(self) -> Self::IntoIter {
563 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {}
566 pub fn empty<'a>() -> &'a Slice<T> {
568 mem::transmute(slice::from_raw_parts(0x1 as *const T, 0))
573 /// Upvars do not get their own node-id. Instead, we use the pair of
574 /// the original var id (that is, the root variable that is referenced
575 /// by the upvar) and the id of the closure expression.
576 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
578 pub var_id: DefIndex,
579 pub closure_expr_id: DefIndex,
582 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
583 pub enum BorrowKind {
584 /// Data must be immutable and is aliasable.
587 /// Data must be immutable but not aliasable. This kind of borrow
588 /// cannot currently be expressed by the user and is used only in
589 /// implicit closure bindings. It is needed when the closure
590 /// is borrowing or mutating a mutable referent, e.g.:
592 /// let x: &mut isize = ...;
593 /// let y = || *x += 5;
595 /// If we were to try to translate this closure into a more explicit
596 /// form, we'd encounter an error with the code as written:
598 /// struct Env { x: & &mut isize }
599 /// let x: &mut isize = ...;
600 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
601 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
603 /// This is then illegal because you cannot mutate a `&mut` found
604 /// in an aliasable location. To solve, you'd have to translate with
605 /// an `&mut` borrow:
607 /// struct Env { x: & &mut isize }
608 /// let x: &mut isize = ...;
609 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
610 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
612 /// Now the assignment to `**env.x` is legal, but creating a
613 /// mutable pointer to `x` is not because `x` is not mutable. We
614 /// could fix this by declaring `x` as `let mut x`. This is ok in
615 /// user code, if awkward, but extra weird for closures, since the
616 /// borrow is hidden.
618 /// So we introduce a "unique imm" borrow -- the referent is
619 /// immutable, but not aliasable. This solves the problem. For
620 /// simplicity, we don't give users the way to express this
621 /// borrow, it's just used when translating closures.
624 /// Data is mutable and not aliasable.
628 /// Information describing the capture of an upvar. This is computed
629 /// during `typeck`, specifically by `regionck`.
630 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
631 pub enum UpvarCapture<'tcx> {
632 /// Upvar is captured by value. This is always true when the
633 /// closure is labeled `move`, but can also be true in other cases
634 /// depending on inference.
637 /// Upvar is captured by reference.
638 ByRef(UpvarBorrow<'tcx>),
641 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
642 pub struct UpvarBorrow<'tcx> {
643 /// The kind of borrow: by-ref upvars have access to shared
644 /// immutable borrows, which are not part of the normal language
646 pub kind: BorrowKind,
648 /// Region of the resulting reference.
649 pub region: ty::Region<'tcx>,
652 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
654 #[derive(Copy, Clone)]
655 pub struct ClosureUpvar<'tcx> {
661 #[derive(Clone, Copy, PartialEq)]
662 pub enum IntVarValue {
664 UintType(ast::UintTy),
667 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
668 pub struct TypeParameterDef {
672 pub has_default: bool,
673 pub object_lifetime_default: ObjectLifetimeDefault,
675 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
676 /// on generic parameter `T`, asserts data behind the parameter
677 /// `T` won't be accessed during the parent type's `Drop` impl.
678 pub pure_wrt_drop: bool,
681 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
682 pub struct RegionParameterDef {
687 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
688 /// on generic parameter `'a`, asserts data of lifetime `'a`
689 /// won't be accessed during the parent type's `Drop` impl.
690 pub pure_wrt_drop: bool,
693 impl RegionParameterDef {
694 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
695 ty::EarlyBoundRegion {
702 pub fn to_bound_region(&self) -> ty::BoundRegion {
703 self.to_early_bound_region_data().to_bound_region()
707 impl ty::EarlyBoundRegion {
708 pub fn to_bound_region(&self) -> ty::BoundRegion {
709 ty::BoundRegion::BrNamed(self.def_id, self.name)
713 /// Information about the formal type/lifetime parameters associated
714 /// with an item or method. Analogous to hir::Generics.
715 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
716 pub struct Generics {
717 pub parent: Option<DefId>,
718 pub parent_regions: u32,
719 pub parent_types: u32,
720 pub regions: Vec<RegionParameterDef>,
721 pub types: Vec<TypeParameterDef>,
723 /// Reverse map to each `TypeParameterDef`'s `index` field, from
724 /// `def_id.index` (`def_id.krate` is the same as the item's).
725 pub type_param_to_index: BTreeMap<DefIndex, u32>,
728 pub has_late_bound_regions: Option<Span>,
732 pub fn parent_count(&self) -> usize {
733 self.parent_regions as usize + self.parent_types as usize
736 pub fn own_count(&self) -> usize {
737 self.regions.len() + self.types.len()
740 pub fn count(&self) -> usize {
741 self.parent_count() + self.own_count()
744 pub fn region_param(&self, param: &EarlyBoundRegion) -> &RegionParameterDef {
745 assert_eq!(self.parent_count(), 0);
746 &self.regions[param.index as usize - self.has_self as usize]
749 pub fn type_param(&self, param: &ParamTy) -> &TypeParameterDef {
750 assert_eq!(self.parent_count(), 0);
751 &self.types[param.idx as usize - self.has_self as usize - self.regions.len()]
755 /// Bounds on generics.
756 #[derive(Clone, Default)]
757 pub struct GenericPredicates<'tcx> {
758 pub parent: Option<DefId>,
759 pub predicates: Vec<Predicate<'tcx>>,
762 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
763 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
765 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
766 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
767 -> InstantiatedPredicates<'tcx> {
768 let mut instantiated = InstantiatedPredicates::empty();
769 self.instantiate_into(tcx, &mut instantiated, substs);
772 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
773 -> InstantiatedPredicates<'tcx> {
774 InstantiatedPredicates {
775 predicates: self.predicates.subst(tcx, substs)
779 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
780 instantiated: &mut InstantiatedPredicates<'tcx>,
781 substs: &Substs<'tcx>) {
782 if let Some(def_id) = self.parent {
783 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
785 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
788 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
789 -> InstantiatedPredicates<'tcx> {
790 let mut instantiated = InstantiatedPredicates::empty();
791 self.instantiate_identity_into(tcx, &mut instantiated);
795 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
796 instantiated: &mut InstantiatedPredicates<'tcx>) {
797 if let Some(def_id) = self.parent {
798 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
800 instantiated.predicates.extend(&self.predicates)
803 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
804 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
805 -> InstantiatedPredicates<'tcx>
807 assert_eq!(self.parent, None);
808 InstantiatedPredicates {
809 predicates: self.predicates.iter().map(|pred| {
810 pred.subst_supertrait(tcx, poly_trait_ref)
816 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
817 pub enum Predicate<'tcx> {
818 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
819 /// the `Self` type of the trait reference and `A`, `B`, and `C`
820 /// would be the type parameters.
821 Trait(PolyTraitPredicate<'tcx>),
823 /// where `T1 == T2`.
824 Equate(PolyEquatePredicate<'tcx>),
827 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
830 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
832 /// where <T as TraitRef>::Name == X, approximately.
833 /// See `ProjectionPredicate` struct for details.
834 Projection(PolyProjectionPredicate<'tcx>),
837 WellFormed(Ty<'tcx>),
839 /// trait must be object-safe
842 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
843 /// for some substitutions `...` and T being a closure type.
844 /// Satisfied (or refuted) once we know the closure's kind.
845 ClosureKind(DefId, ClosureKind),
848 Subtype(PolySubtypePredicate<'tcx>),
851 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
852 /// Performs a substitution suitable for going from a
853 /// poly-trait-ref to supertraits that must hold if that
854 /// poly-trait-ref holds. This is slightly different from a normal
855 /// substitution in terms of what happens with bound regions. See
856 /// lengthy comment below for details.
857 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
858 trait_ref: &ty::PolyTraitRef<'tcx>)
859 -> ty::Predicate<'tcx>
861 // The interaction between HRTB and supertraits is not entirely
862 // obvious. Let me walk you (and myself) through an example.
864 // Let's start with an easy case. Consider two traits:
866 // trait Foo<'a> : Bar<'a,'a> { }
867 // trait Bar<'b,'c> { }
869 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
870 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
871 // knew that `Foo<'x>` (for any 'x) then we also know that
872 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
873 // normal substitution.
875 // In terms of why this is sound, the idea is that whenever there
876 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
877 // holds. So if there is an impl of `T:Foo<'a>` that applies to
878 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
881 // Another example to be careful of is this:
883 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
884 // trait Bar1<'b,'c> { }
886 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
887 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
888 // reason is similar to the previous example: any impl of
889 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
890 // basically we would want to collapse the bound lifetimes from
891 // the input (`trait_ref`) and the supertraits.
893 // To achieve this in practice is fairly straightforward. Let's
894 // consider the more complicated scenario:
896 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
897 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
898 // where both `'x` and `'b` would have a DB index of 1.
899 // The substitution from the input trait-ref is therefore going to be
900 // `'a => 'x` (where `'x` has a DB index of 1).
901 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
902 // early-bound parameter and `'b' is a late-bound parameter with a
904 // - If we replace `'a` with `'x` from the input, it too will have
905 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
906 // just as we wanted.
908 // There is only one catch. If we just apply the substitution `'a
909 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
910 // adjust the DB index because we substituting into a binder (it
911 // tries to be so smart...) resulting in `for<'x> for<'b>
912 // Bar1<'x,'b>` (we have no syntax for this, so use your
913 // imagination). Basically the 'x will have DB index of 2 and 'b
914 // will have DB index of 1. Not quite what we want. So we apply
915 // the substitution to the *contents* of the trait reference,
916 // rather than the trait reference itself (put another way, the
917 // substitution code expects equal binding levels in the values
918 // from the substitution and the value being substituted into, and
919 // this trick achieves that).
921 let substs = &trait_ref.0.substs;
923 Predicate::Trait(ty::Binder(ref data)) =>
924 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
925 Predicate::Equate(ty::Binder(ref data)) =>
926 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
927 Predicate::Subtype(ty::Binder(ref data)) =>
928 Predicate::Subtype(ty::Binder(data.subst(tcx, substs))),
929 Predicate::RegionOutlives(ty::Binder(ref data)) =>
930 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
931 Predicate::TypeOutlives(ty::Binder(ref data)) =>
932 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
933 Predicate::Projection(ty::Binder(ref data)) =>
934 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
935 Predicate::WellFormed(data) =>
936 Predicate::WellFormed(data.subst(tcx, substs)),
937 Predicate::ObjectSafe(trait_def_id) =>
938 Predicate::ObjectSafe(trait_def_id),
939 Predicate::ClosureKind(closure_def_id, kind) =>
940 Predicate::ClosureKind(closure_def_id, kind),
945 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
946 pub struct TraitPredicate<'tcx> {
947 pub trait_ref: TraitRef<'tcx>
949 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
951 impl<'tcx> TraitPredicate<'tcx> {
952 pub fn def_id(&self) -> DefId {
953 self.trait_ref.def_id
956 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
957 self.trait_ref.input_types()
960 pub fn self_ty(&self) -> Ty<'tcx> {
961 self.trait_ref.self_ty()
965 impl<'tcx> PolyTraitPredicate<'tcx> {
966 pub fn def_id(&self) -> DefId {
967 // ok to skip binder since trait def-id does not care about regions
972 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
973 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
974 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
976 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
977 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
978 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
979 pub type PolyRegionOutlivesPredicate<'tcx> = PolyOutlivesPredicate<ty::Region<'tcx>,
981 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
983 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
984 pub struct SubtypePredicate<'tcx> {
985 pub a_is_expected: bool,
989 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
991 /// This kind of predicate has no *direct* correspondent in the
992 /// syntax, but it roughly corresponds to the syntactic forms:
994 /// 1. `T : TraitRef<..., Item=Type>`
995 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
997 /// In particular, form #1 is "desugared" to the combination of a
998 /// normal trait predicate (`T : TraitRef<...>`) and one of these
999 /// predicates. Form #2 is a broader form in that it also permits
1000 /// equality between arbitrary types. Processing an instance of Form
1001 /// #2 eventually yields one of these `ProjectionPredicate`
1002 /// instances to normalize the LHS.
1003 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1004 pub struct ProjectionPredicate<'tcx> {
1005 pub projection_ty: ProjectionTy<'tcx>,
1009 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1011 impl<'tcx> PolyProjectionPredicate<'tcx> {
1012 pub fn to_poly_trait_ref(&self, tcx: TyCtxt) -> PolyTraitRef<'tcx> {
1013 // Note: unlike with TraitRef::to_poly_trait_ref(),
1014 // self.0.trait_ref is permitted to have escaping regions.
1015 // This is because here `self` has a `Binder` and so does our
1016 // return value, so we are preserving the number of binding
1018 ty::Binder(self.0.projection_ty.trait_ref(tcx))
1022 pub trait ToPolyTraitRef<'tcx> {
1023 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1026 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1027 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1028 assert!(!self.has_escaping_regions());
1029 ty::Binder(self.clone())
1033 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1034 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1035 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1039 pub trait ToPredicate<'tcx> {
1040 fn to_predicate(&self) -> Predicate<'tcx>;
1043 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1044 fn to_predicate(&self) -> Predicate<'tcx> {
1045 // we're about to add a binder, so let's check that we don't
1046 // accidentally capture anything, or else that might be some
1047 // weird debruijn accounting.
1048 assert!(!self.has_escaping_regions());
1050 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
1051 trait_ref: self.clone()
1056 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1057 fn to_predicate(&self) -> Predicate<'tcx> {
1058 ty::Predicate::Trait(self.to_poly_trait_predicate())
1062 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
1063 fn to_predicate(&self) -> Predicate<'tcx> {
1064 Predicate::Equate(self.clone())
1068 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1069 fn to_predicate(&self) -> Predicate<'tcx> {
1070 Predicate::RegionOutlives(self.clone())
1074 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1075 fn to_predicate(&self) -> Predicate<'tcx> {
1076 Predicate::TypeOutlives(self.clone())
1080 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1081 fn to_predicate(&self) -> Predicate<'tcx> {
1082 Predicate::Projection(self.clone())
1086 impl<'tcx> Predicate<'tcx> {
1087 /// Iterates over the types in this predicate. Note that in all
1088 /// cases this is skipping over a binder, so late-bound regions
1089 /// with depth 0 are bound by the predicate.
1090 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1091 let vec: Vec<_> = match *self {
1092 ty::Predicate::Trait(ref data) => {
1093 data.skip_binder().input_types().collect()
1095 ty::Predicate::Equate(ty::Binder(ref data)) => {
1096 vec![data.0, data.1]
1098 ty::Predicate::Subtype(ty::Binder(SubtypePredicate { a, b, a_is_expected: _ })) => {
1101 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
1104 ty::Predicate::RegionOutlives(..) => {
1107 ty::Predicate::Projection(ref data) => {
1108 data.0.projection_ty.substs.types().chain(Some(data.0.ty)).collect()
1110 ty::Predicate::WellFormed(data) => {
1113 ty::Predicate::ObjectSafe(_trait_def_id) => {
1116 ty::Predicate::ClosureKind(_closure_def_id, _kind) => {
1121 // The only reason to collect into a vector here is that I was
1122 // too lazy to make the full (somewhat complicated) iterator
1123 // type that would be needed here. But I wanted this fn to
1124 // return an iterator conceptually, rather than a `Vec`, so as
1125 // to be closer to `Ty::walk`.
1129 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1131 Predicate::Trait(ref t) => {
1132 Some(t.to_poly_trait_ref())
1134 Predicate::Projection(..) |
1135 Predicate::Equate(..) |
1136 Predicate::Subtype(..) |
1137 Predicate::RegionOutlives(..) |
1138 Predicate::WellFormed(..) |
1139 Predicate::ObjectSafe(..) |
1140 Predicate::ClosureKind(..) |
1141 Predicate::TypeOutlives(..) => {
1148 /// Represents the bounds declared on a particular set of type
1149 /// parameters. Should eventually be generalized into a flag list of
1150 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1151 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1152 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1153 /// the `GenericPredicates` are expressed in terms of the bound type
1154 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1155 /// represented a set of bounds for some particular instantiation,
1156 /// meaning that the generic parameters have been substituted with
1161 /// struct Foo<T,U:Bar<T>> { ... }
1163 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1164 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1165 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1166 /// [usize:Bar<isize>]]`.
1168 pub struct InstantiatedPredicates<'tcx> {
1169 pub predicates: Vec<Predicate<'tcx>>,
1172 impl<'tcx> InstantiatedPredicates<'tcx> {
1173 pub fn empty() -> InstantiatedPredicates<'tcx> {
1174 InstantiatedPredicates { predicates: vec![] }
1177 pub fn is_empty(&self) -> bool {
1178 self.predicates.is_empty()
1182 /// When type checking, we use the `ParamEnv` to track
1183 /// details about the set of where-clauses that are in scope at this
1184 /// particular point.
1185 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1186 pub struct ParamEnv<'tcx> {
1187 /// Obligations that the caller must satisfy. This is basically
1188 /// the set of bounds on the in-scope type parameters, translated
1189 /// into Obligations, and elaborated and normalized.
1190 pub caller_bounds: &'tcx Slice<ty::Predicate<'tcx>>,
1192 /// Typically, this is `Reveal::UserFacing`, but during trans we
1193 /// want `Reveal::All` -- note that this is always paired with an
1194 /// empty environment. To get that, use `ParamEnv::reveal()`.
1195 pub reveal: traits::Reveal,
1198 impl<'tcx> ParamEnv<'tcx> {
1199 /// Creates a suitable environment in which to perform trait
1200 /// queries on the given value. This will either be `self` *or*
1201 /// the empty environment, depending on whether `value` references
1202 /// type parameters that are in scope. (If it doesn't, then any
1203 /// judgements should be completely independent of the context,
1204 /// and hence we can safely use the empty environment so as to
1205 /// enable more sharing across functions.)
1207 /// NB: This is a mildly dubious thing to do, in that a function
1208 /// (or other environment) might have wacky where-clauses like
1209 /// `where Box<u32>: Copy`, which are clearly never
1210 /// satisfiable. The code will at present ignore these,
1211 /// effectively, when type-checking the body of said
1212 /// function. This preserves existing behavior in any
1213 /// case. --nmatsakis
1214 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1215 assert!(!value.needs_infer());
1216 if value.has_param_types() || value.has_self_ty() {
1223 param_env: ParamEnv::empty(self.reveal),
1230 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1231 pub struct ParamEnvAnd<'tcx, T> {
1232 pub param_env: ParamEnv<'tcx>,
1236 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1237 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1238 (self.param_env, self.value)
1242 #[derive(Copy, Clone, Debug)]
1243 pub struct Destructor {
1244 /// The def-id of the destructor method
1249 flags AdtFlags: u32 {
1250 const NO_ADT_FLAGS = 0,
1251 const IS_ENUM = 1 << 0,
1252 const IS_PHANTOM_DATA = 1 << 1,
1253 const IS_FUNDAMENTAL = 1 << 2,
1254 const IS_UNION = 1 << 3,
1255 const IS_BOX = 1 << 4,
1260 pub struct VariantDef {
1261 /// The variant's DefId. If this is a tuple-like struct,
1262 /// this is the DefId of the struct's ctor.
1264 pub name: Name, // struct's name if this is a struct
1265 pub discr: VariantDiscr,
1266 pub fields: Vec<FieldDef>,
1267 pub ctor_kind: CtorKind,
1270 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1271 pub enum VariantDiscr {
1272 /// Explicit value for this variant, i.e. `X = 123`.
1273 /// The `DefId` corresponds to the embedded constant.
1276 /// The previous variant's discriminant plus one.
1277 /// For efficiency reasons, the distance from the
1278 /// last `Explicit` discriminant is being stored,
1279 /// or `0` for the first variant, if it has none.
1284 pub struct FieldDef {
1287 pub vis: Visibility,
1290 /// The definition of an abstract data type - a struct or enum.
1292 /// These are all interned (by intern_adt_def) into the adt_defs
1296 pub variants: Vec<VariantDef>,
1298 pub repr: ReprOptions,
1301 impl PartialEq for AdtDef {
1302 // AdtDef are always interned and this is part of TyS equality
1304 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1307 impl Eq for AdtDef {}
1309 impl Hash for AdtDef {
1311 fn hash<H: Hasher>(&self, s: &mut H) {
1312 (self as *const AdtDef).hash(s)
1316 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1317 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1322 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1325 impl<'a, 'gcx, 'tcx> HashStable<StableHashingContext<'a, 'gcx, 'tcx>> for AdtDef {
1326 fn hash_stable<W: StableHasherResult>(&self,
1327 hcx: &mut StableHashingContext<'a, 'gcx, 'tcx>,
1328 hasher: &mut StableHasher<W>) {
1336 did.hash_stable(hcx, hasher);
1337 variants.hash_stable(hcx, hasher);
1338 flags.hash_stable(hcx, hasher);
1339 repr.hash_stable(hcx, hasher);
1343 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1344 pub enum AdtKind { Struct, Union, Enum }
1347 #[derive(RustcEncodable, RustcDecodable, Default)]
1348 flags ReprFlags: u8 {
1349 const IS_C = 1 << 0,
1350 const IS_PACKED = 1 << 1,
1351 const IS_SIMD = 1 << 2,
1352 // Internal only for now. If true, don't reorder fields.
1353 const IS_LINEAR = 1 << 3,
1355 // Any of these flags being set prevent field reordering optimisation.
1356 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1357 ReprFlags::IS_PACKED.bits |
1358 ReprFlags::IS_SIMD.bits |
1359 ReprFlags::IS_LINEAR.bits,
1363 impl_stable_hash_for!(struct ReprFlags {
1369 /// Represents the repr options provided by the user,
1370 #[derive(Copy, Clone, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1371 pub struct ReprOptions {
1372 pub int: Option<attr::IntType>,
1374 pub flags: ReprFlags,
1377 impl_stable_hash_for!(struct ReprOptions {
1384 pub fn new(tcx: TyCtxt, did: DefId) -> ReprOptions {
1385 let mut flags = ReprFlags::empty();
1386 let mut size = None;
1387 let mut max_align = 0;
1388 for attr in tcx.get_attrs(did).iter() {
1389 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1390 flags.insert(match r {
1391 attr::ReprExtern => ReprFlags::IS_C,
1392 attr::ReprPacked => ReprFlags::IS_PACKED,
1393 attr::ReprSimd => ReprFlags::IS_SIMD,
1394 attr::ReprInt(i) => {
1398 attr::ReprAlign(align) => {
1399 max_align = cmp::max(align, max_align);
1406 // FIXME(eddyb) This is deprecated and should be removed.
1407 if tcx.has_attr(did, "simd") {
1408 flags.insert(ReprFlags::IS_SIMD);
1411 // This is here instead of layout because the choice must make it into metadata.
1412 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1413 flags.insert(ReprFlags::IS_LINEAR);
1415 ReprOptions { int: size, align: max_align, flags: flags }
1419 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1421 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1423 pub fn packed(&self) -> bool { self.flags.contains(ReprFlags::IS_PACKED) }
1425 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1427 pub fn discr_type(&self) -> attr::IntType {
1428 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Is))
1431 /// Returns true if this `#[repr()]` should inhabit "smart enum
1432 /// layout" optimizations, such as representing `Foo<&T>` as a
1434 pub fn inhibit_enum_layout_opt(&self) -> bool {
1435 self.c() || self.int.is_some()
1439 impl<'a, 'gcx, 'tcx> AdtDef {
1443 variants: Vec<VariantDef>,
1444 repr: ReprOptions) -> Self {
1445 let mut flags = AdtFlags::NO_ADT_FLAGS;
1446 let attrs = tcx.get_attrs(did);
1447 if attr::contains_name(&attrs, "fundamental") {
1448 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1450 if Some(did) == tcx.lang_items().phantom_data() {
1451 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1453 if Some(did) == tcx.lang_items().owned_box() {
1454 flags = flags | AdtFlags::IS_BOX;
1457 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
1458 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
1459 AdtKind::Struct => {}
1470 pub fn is_struct(&self) -> bool {
1471 !self.is_union() && !self.is_enum()
1475 pub fn is_union(&self) -> bool {
1476 self.flags.intersects(AdtFlags::IS_UNION)
1480 pub fn is_enum(&self) -> bool {
1481 self.flags.intersects(AdtFlags::IS_ENUM)
1484 /// Returns the kind of the ADT - Struct or Enum.
1486 pub fn adt_kind(&self) -> AdtKind {
1489 } else if self.is_union() {
1496 pub fn descr(&self) -> &'static str {
1497 match self.adt_kind() {
1498 AdtKind::Struct => "struct",
1499 AdtKind::Union => "union",
1500 AdtKind::Enum => "enum",
1504 pub fn variant_descr(&self) -> &'static str {
1505 match self.adt_kind() {
1506 AdtKind::Struct => "struct",
1507 AdtKind::Union => "union",
1508 AdtKind::Enum => "variant",
1512 /// Returns whether this type is #[fundamental] for the purposes
1513 /// of coherence checking.
1515 pub fn is_fundamental(&self) -> bool {
1516 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
1519 /// Returns true if this is PhantomData<T>.
1521 pub fn is_phantom_data(&self) -> bool {
1522 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
1525 /// Returns true if this is Box<T>.
1527 pub fn is_box(&self) -> bool {
1528 self.flags.intersects(AdtFlags::IS_BOX)
1531 /// Returns whether this type has a destructor.
1532 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
1533 self.destructor(tcx).is_some()
1536 /// Asserts this is a struct and returns the struct's unique
1538 pub fn struct_variant(&self) -> &VariantDef {
1539 assert!(!self.is_enum());
1544 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
1545 tcx.predicates_of(self.did)
1548 /// Returns an iterator over all fields contained
1551 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
1552 self.variants.iter().flat_map(|v| v.fields.iter())
1556 pub fn is_univariant(&self) -> bool {
1557 self.variants.len() == 1
1560 pub fn is_payloadfree(&self) -> bool {
1561 !self.variants.is_empty() &&
1562 self.variants.iter().all(|v| v.fields.is_empty())
1565 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
1568 .find(|v| v.did == vid)
1569 .expect("variant_with_id: unknown variant")
1572 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1575 .position(|v| v.did == vid)
1576 .expect("variant_index_with_id: unknown variant")
1579 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
1581 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
1582 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
1583 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.struct_variant(),
1584 _ => bug!("unexpected def {:?} in variant_of_def", def)
1589 pub fn discriminants(&'a self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1590 -> impl Iterator<Item=ConstInt> + 'a {
1591 let param_env = ParamEnv::empty(traits::Reveal::UserFacing);
1592 let repr_type = self.repr.discr_type();
1593 let initial = repr_type.initial_discriminant(tcx.global_tcx());
1594 let mut prev_discr = None::<ConstInt>;
1595 self.variants.iter().map(move |v| {
1596 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr());
1597 if let VariantDiscr::Explicit(expr_did) = v.discr {
1598 let substs = Substs::identity_for_item(tcx.global_tcx(), expr_did);
1599 match tcx.const_eval(param_env.and((expr_did, substs))) {
1600 Ok(ConstVal::Integral(v)) => {
1604 if !expr_did.is_local() {
1605 span_bug!(tcx.def_span(expr_did),
1606 "variant discriminant evaluation succeeded \
1607 in its crate but failed locally: {:?}", err);
1612 prev_discr = Some(discr);
1618 /// Compute the discriminant value used by a specific variant.
1619 /// Unlike `discriminants`, this is (amortized) constant-time,
1620 /// only doing at most one query for evaluating an explicit
1621 /// discriminant (the last one before the requested variant),
1622 /// assuming there are no constant-evaluation errors there.
1623 pub fn discriminant_for_variant(&self,
1624 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1625 variant_index: usize)
1627 let param_env = ParamEnv::empty(traits::Reveal::UserFacing);
1628 let repr_type = self.repr.discr_type();
1629 let mut explicit_value = repr_type.initial_discriminant(tcx.global_tcx());
1630 let mut explicit_index = variant_index;
1632 match self.variants[explicit_index].discr {
1633 ty::VariantDiscr::Relative(0) => break,
1634 ty::VariantDiscr::Relative(distance) => {
1635 explicit_index -= distance;
1637 ty::VariantDiscr::Explicit(expr_did) => {
1638 let substs = Substs::identity_for_item(tcx.global_tcx(), expr_did);
1639 match tcx.const_eval(param_env.and((expr_did, substs))) {
1640 Ok(ConstVal::Integral(v)) => {
1645 if !expr_did.is_local() {
1646 span_bug!(tcx.def_span(expr_did),
1647 "variant discriminant evaluation succeeded \
1648 in its crate but failed locally: {:?}", err);
1650 if explicit_index == 0 {
1653 explicit_index -= 1;
1659 let discr = explicit_value.to_u128_unchecked()
1660 .wrapping_add((variant_index - explicit_index) as u128);
1662 attr::UnsignedInt(ty) => {
1663 ConstInt::new_unsigned_truncating(discr, ty,
1664 tcx.sess.target.uint_type)
1666 attr::SignedInt(ty) => {
1667 ConstInt::new_signed_truncating(discr as i128, ty,
1668 tcx.sess.target.int_type)
1673 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
1674 tcx.adt_destructor(self.did)
1677 /// Returns a list of types such that `Self: Sized` if and only
1678 /// if that type is Sized, or `TyErr` if this type is recursive.
1680 /// Oddly enough, checking that the sized-constraint is Sized is
1681 /// actually more expressive than checking all members:
1682 /// the Sized trait is inductive, so an associated type that references
1683 /// Self would prevent its containing ADT from being Sized.
1685 /// Due to normalization being eager, this applies even if
1686 /// the associated type is behind a pointer, e.g. issue #31299.
1687 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
1688 match queries::adt_sized_constraint::try_get(tcx, DUMMY_SP, self.did) {
1691 debug!("adt_sized_constraint: {:?} is recursive", self);
1692 // This should be reported as an error by `check_representable`.
1694 // Consider the type as Sized in the meanwhile to avoid
1695 // further errors. Delay our `bug` diagnostic here to get
1696 // emitted later as well in case we accidentally otherwise don't
1699 tcx.intern_type_list(&[tcx.types.err])
1704 fn sized_constraint_for_ty(&self,
1705 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1708 let result = match ty.sty {
1709 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
1710 TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
1711 TyArray(..) | TyClosure(..) | TyGenerator(..) | TyNever => {
1715 TyStr | TyDynamic(..) | TySlice(_) | TyError => {
1716 // these are never sized - return the target type
1720 TyTuple(ref tys, _) => {
1723 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
1727 TyAdt(adt, substs) => {
1729 let adt_tys = adt.sized_constraint(tcx);
1730 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
1733 .map(|ty| ty.subst(tcx, substs))
1734 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
1738 TyProjection(..) | TyAnon(..) => {
1739 // must calculate explicitly.
1740 // FIXME: consider special-casing always-Sized projections
1745 // perf hack: if there is a `T: Sized` bound, then
1746 // we know that `T` is Sized and do not need to check
1749 let sized_trait = match tcx.lang_items().sized_trait() {
1751 _ => return vec![ty]
1753 let sized_predicate = Binder(TraitRef {
1754 def_id: sized_trait,
1755 substs: tcx.mk_substs_trait(ty, &[])
1757 let predicates = tcx.predicates_of(self.did).predicates;
1758 if predicates.into_iter().any(|p| p == sized_predicate) {
1766 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
1770 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
1775 impl<'a, 'gcx, 'tcx> VariantDef {
1777 pub fn find_field_named(&self, name: ast::Name) -> Option<&FieldDef> {
1778 self.index_of_field_named(name).map(|index| &self.fields[index])
1781 pub fn index_of_field_named(&self, name: ast::Name) -> Option<usize> {
1782 if let Some(index) = self.fields.iter().position(|f| f.name == name) {
1785 let mut ident = name.to_ident();
1786 while ident.ctxt != SyntaxContext::empty() {
1787 ident.ctxt.remove_mark();
1788 if let Some(field) = self.fields.iter().position(|f| f.name.to_ident() == ident) {
1796 pub fn field_named(&self, name: ast::Name) -> &FieldDef {
1797 self.find_field_named(name).unwrap()
1801 impl<'a, 'gcx, 'tcx> FieldDef {
1802 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1803 tcx.type_of(self.did).subst(tcx, subst)
1807 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1808 pub enum ClosureKind {
1809 // Warning: Ordering is significant here! The ordering is chosen
1810 // because the trait Fn is a subtrait of FnMut and so in turn, and
1811 // hence we order it so that Fn < FnMut < FnOnce.
1817 impl<'a, 'tcx> ClosureKind {
1818 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
1820 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
1821 ClosureKind::FnMut => {
1822 tcx.require_lang_item(FnMutTraitLangItem)
1824 ClosureKind::FnOnce => {
1825 tcx.require_lang_item(FnOnceTraitLangItem)
1830 /// True if this a type that impls this closure kind
1831 /// must also implement `other`.
1832 pub fn extends(self, other: ty::ClosureKind) -> bool {
1833 match (self, other) {
1834 (ClosureKind::Fn, ClosureKind::Fn) => true,
1835 (ClosureKind::Fn, ClosureKind::FnMut) => true,
1836 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
1837 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
1838 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
1839 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
1845 impl<'tcx> TyS<'tcx> {
1846 /// Iterator that walks `self` and any types reachable from
1847 /// `self`, in depth-first order. Note that just walks the types
1848 /// that appear in `self`, it does not descend into the fields of
1849 /// structs or variants. For example:
1852 /// isize => { isize }
1853 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
1854 /// [isize] => { [isize], isize }
1856 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
1857 TypeWalker::new(self)
1860 /// Iterator that walks the immediate children of `self`. Hence
1861 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
1862 /// (but not `i32`, like `walk`).
1863 pub fn walk_shallow(&'tcx self) -> AccIntoIter<walk::TypeWalkerArray<'tcx>> {
1864 walk::walk_shallow(self)
1867 /// Walks `ty` and any types appearing within `ty`, invoking the
1868 /// callback `f` on each type. If the callback returns false, then the
1869 /// children of the current type are ignored.
1871 /// Note: prefer `ty.walk()` where possible.
1872 pub fn maybe_walk<F>(&'tcx self, mut f: F)
1873 where F : FnMut(Ty<'tcx>) -> bool
1875 let mut walker = self.walk();
1876 while let Some(ty) = walker.next() {
1878 walker.skip_current_subtree();
1884 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1885 pub enum LvaluePreference {
1890 impl LvaluePreference {
1891 pub fn from_mutbl(m: hir::Mutability) -> Self {
1893 hir::MutMutable => PreferMutLvalue,
1894 hir::MutImmutable => NoPreference,
1900 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
1902 hir::MutMutable => MutBorrow,
1903 hir::MutImmutable => ImmBorrow,
1907 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
1908 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
1909 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
1911 pub fn to_mutbl_lossy(self) -> hir::Mutability {
1913 MutBorrow => hir::MutMutable,
1914 ImmBorrow => hir::MutImmutable,
1916 // We have no type corresponding to a unique imm borrow, so
1917 // use `&mut`. It gives all the capabilities of an `&uniq`
1918 // and hence is a safe "over approximation".
1919 UniqueImmBorrow => hir::MutMutable,
1923 pub fn to_user_str(&self) -> &'static str {
1925 MutBorrow => "mutable",
1926 ImmBorrow => "immutable",
1927 UniqueImmBorrow => "uniquely immutable",
1932 #[derive(Debug, Clone)]
1933 pub enum Attributes<'gcx> {
1934 Owned(Rc<[ast::Attribute]>),
1935 Borrowed(&'gcx [ast::Attribute])
1938 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
1939 type Target = [ast::Attribute];
1941 fn deref(&self) -> &[ast::Attribute] {
1943 &Attributes::Owned(ref data) => &data,
1944 &Attributes::Borrowed(data) => data
1949 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
1950 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
1951 self.typeck_tables_of(self.hir.body_owner_def_id(body))
1954 /// Returns an iterator of the def-ids for all body-owners in this
1955 /// crate. If you would prefer to iterate over the bodies
1956 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
1957 pub fn body_owners(self) -> impl Iterator<Item = DefId> + 'a {
1961 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
1964 pub fn expr_span(self, id: NodeId) -> Span {
1965 match self.hir.find(id) {
1966 Some(hir_map::NodeExpr(e)) => {
1970 bug!("Node id {} is not an expr: {:?}", id, f);
1973 bug!("Node id {} is not present in the node map", id);
1978 pub fn local_var_name_str(self, id: NodeId) -> InternedString {
1979 match self.hir.find(id) {
1980 Some(hir_map::NodeBinding(pat)) => {
1982 hir::PatKind::Binding(_, _, ref path1, _) => path1.node.as_str(),
1984 bug!("Variable id {} maps to {:?}, not local", id, pat);
1988 r => bug!("Variable id {} maps to {:?}, not local", id, r),
1992 pub fn local_var_name_str_def_index(self, def_index: DefIndex) -> InternedString {
1993 let node_id = self.hir.as_local_node_id(DefId::local(def_index)).unwrap();
1994 self.local_var_name_str(node_id)
1997 pub fn expr_is_lval(self, expr: &hir::Expr) -> bool {
1999 hir::ExprPath(hir::QPath::Resolved(_, ref path)) => {
2001 Def::Local(..) | Def::Upvar(..) | Def::Static(..) | Def::Err => true,
2006 hir::ExprType(ref e, _) => {
2007 self.expr_is_lval(e)
2010 hir::ExprUnary(hir::UnDeref, _) |
2011 hir::ExprField(..) |
2012 hir::ExprTupField(..) |
2013 hir::ExprIndex(..) => {
2017 // Partially qualified paths in expressions can only legally
2018 // refer to associated items which are always rvalues.
2019 hir::ExprPath(hir::QPath::TypeRelative(..)) |
2022 hir::ExprMethodCall(..) |
2023 hir::ExprStruct(..) |
2026 hir::ExprMatch(..) |
2027 hir::ExprClosure(..) |
2028 hir::ExprBlock(..) |
2029 hir::ExprRepeat(..) |
2030 hir::ExprArray(..) |
2031 hir::ExprBreak(..) |
2032 hir::ExprAgain(..) |
2034 hir::ExprWhile(..) |
2036 hir::ExprAssign(..) |
2037 hir::ExprInlineAsm(..) |
2038 hir::ExprAssignOp(..) |
2040 hir::ExprUnary(..) |
2042 hir::ExprAddrOf(..) |
2043 hir::ExprBinary(..) |
2044 hir::ExprYield(..) |
2045 hir::ExprCast(..) => {
2051 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2052 self.associated_items(id)
2053 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2057 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2058 self.associated_items(did).any(|item| {
2059 item.relevant_for_never()
2063 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2064 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2065 match self.hir.get(node_id) {
2066 hir_map::NodeTraitItem(_) | hir_map::NodeImplItem(_) => true,
2070 match self.describe_def(def_id).expect("no def for def-id") {
2071 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2076 if is_associated_item {
2077 Some(self.associated_item(def_id))
2083 fn associated_item_from_trait_item_ref(self,
2084 parent_def_id: DefId,
2085 parent_vis: &hir::Visibility,
2086 trait_item_ref: &hir::TraitItemRef)
2088 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2089 let (kind, has_self) = match trait_item_ref.kind {
2090 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2091 hir::AssociatedItemKind::Method { has_self } => {
2092 (ty::AssociatedKind::Method, has_self)
2094 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2098 name: trait_item_ref.name,
2100 // Visibility of trait items is inherited from their traits.
2101 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2102 defaultness: trait_item_ref.defaultness,
2104 container: TraitContainer(parent_def_id),
2105 method_has_self_argument: has_self
2109 fn associated_item_from_impl_item_ref(self,
2110 parent_def_id: DefId,
2111 impl_item_ref: &hir::ImplItemRef)
2113 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2114 let (kind, has_self) = match impl_item_ref.kind {
2115 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2116 hir::AssociatedItemKind::Method { has_self } => {
2117 (ty::AssociatedKind::Method, has_self)
2119 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2122 ty::AssociatedItem {
2123 name: impl_item_ref.name,
2125 // Visibility of trait impl items doesn't matter.
2126 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2127 defaultness: impl_item_ref.defaultness,
2129 container: ImplContainer(parent_def_id),
2130 method_has_self_argument: has_self
2134 #[inline] // FIXME(#35870) Avoid closures being unexported due to impl Trait.
2135 pub fn associated_items(self, def_id: DefId)
2136 -> impl Iterator<Item = ty::AssociatedItem> + 'a {
2137 let def_ids = self.associated_item_def_ids(def_id);
2138 (0..def_ids.len()).map(move |i| self.associated_item(def_ids[i]))
2141 /// Returns true if the impls are the same polarity and are implementing
2142 /// a trait which contains no items
2143 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2144 if !self.sess.features.borrow().overlapping_marker_traits {
2147 let trait1_is_empty = self.impl_trait_ref(def_id1)
2148 .map_or(false, |trait_ref| {
2149 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2151 let trait2_is_empty = self.impl_trait_ref(def_id2)
2152 .map_or(false, |trait_ref| {
2153 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2155 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2160 // Returns `ty::VariantDef` if `def` refers to a struct,
2161 // or variant or their constructors, panics otherwise.
2162 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2164 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2165 let enum_did = self.parent_def_id(did).unwrap();
2166 self.adt_def(enum_did).variant_with_id(did)
2168 Def::Struct(did) | Def::Union(did) => {
2169 self.adt_def(did).struct_variant()
2171 Def::StructCtor(ctor_did, ..) => {
2172 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2173 self.adt_def(did).struct_variant()
2175 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2179 pub fn def_key(self, id: DefId) -> hir_map::DefKey {
2181 self.hir.def_key(id)
2183 self.sess.cstore.def_key(id)
2187 /// Convert a `DefId` into its fully expanded `DefPath` (every
2188 /// `DefId` is really just an interned def-path).
2190 /// Note that if `id` is not local to this crate, the result will
2191 /// be a non-local `DefPath`.
2192 pub fn def_path(self, id: DefId) -> hir_map::DefPath {
2194 self.hir.def_path(id)
2196 self.sess.cstore.def_path(id)
2201 pub fn def_path_hash(self, def_id: DefId) -> hir_map::DefPathHash {
2202 if def_id.is_local() {
2203 self.hir.definitions().def_path_hash(def_id.index)
2205 self.sess.cstore.def_path_hash(def_id)
2209 pub fn item_name(self, id: DefId) -> InternedString {
2210 if let Some(id) = self.hir.as_local_node_id(id) {
2211 self.hir.name(id).as_str()
2212 } else if id.index == CRATE_DEF_INDEX {
2213 self.original_crate_name(id.krate).as_str()
2215 let def_key = self.sess.cstore.def_key(id);
2216 // The name of a StructCtor is that of its struct parent.
2217 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2218 self.item_name(DefId {
2220 index: def_key.parent.unwrap()
2223 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2224 bug!("item_name: no name for {:?}", self.def_path(id));
2230 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2231 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2235 ty::InstanceDef::Item(did) => {
2236 self.optimized_mir(did)
2238 ty::InstanceDef::Intrinsic(..) |
2239 ty::InstanceDef::FnPtrShim(..) |
2240 ty::InstanceDef::Virtual(..) |
2241 ty::InstanceDef::ClosureOnceShim { .. } |
2242 ty::InstanceDef::DropGlue(..) |
2243 ty::InstanceDef::CloneShim(..) => {
2244 self.mir_shims(instance)
2249 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2250 /// Returns None if there is no MIR for the DefId
2251 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2252 if self.is_mir_available(did) {
2253 Some(self.optimized_mir(did))
2259 /// Get the attributes of a definition.
2260 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2261 if let Some(id) = self.hir.as_local_node_id(did) {
2262 Attributes::Borrowed(self.hir.attrs(id))
2264 Attributes::Owned(self.item_attrs(did))
2268 /// Determine whether an item is annotated with an attribute
2269 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2270 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2273 pub fn trait_has_default_impl(self, trait_def_id: DefId) -> bool {
2274 self.trait_def(trait_def_id).has_default_impl
2277 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
2278 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
2281 /// Given the def_id of an impl, return the def_id of the trait it implements.
2282 /// If it implements no trait, return `None`.
2283 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2284 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2287 /// If the given def ID describes a method belonging to an impl, return the
2288 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2289 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2290 let item = if def_id.krate != LOCAL_CRATE {
2291 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2292 Some(self.associated_item(def_id))
2297 self.opt_associated_item(def_id)
2301 Some(trait_item) => {
2302 match trait_item.container {
2303 TraitContainer(_) => None,
2304 ImplContainer(def_id) => Some(def_id),
2311 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2312 /// with the name of the crate containing the impl.
2313 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2314 if impl_did.is_local() {
2315 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2316 Ok(self.hir.span(node_id))
2318 Err(self.crate_name(impl_did.krate))
2322 pub fn adjust(self, name: Name, scope: DefId, block: NodeId) -> (Ident, DefId) {
2323 self.adjust_ident(name.to_ident(), scope, block)
2326 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
2327 let expansion = match scope.krate {
2328 LOCAL_CRATE => self.hir.definitions().expansion(scope.index),
2331 let scope = match ident.ctxt.adjust(expansion) {
2332 Some(macro_def) => self.hir.definitions().macro_def_scope(macro_def),
2333 None => self.hir.get_module_parent(block),
2339 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2340 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2341 F: FnOnce(&[hir::Freevar]) -> T,
2343 let hir_id = self.hir.node_to_hir_id(fid);
2344 match self.freevars(hir_id) {
2351 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
2354 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2355 let parent_id = tcx.hir.get_parent(id);
2356 let parent_def_id = tcx.hir.local_def_id(parent_id);
2357 let parent_item = tcx.hir.expect_item(parent_id);
2358 match parent_item.node {
2359 hir::ItemImpl(.., ref impl_item_refs) => {
2360 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2361 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2363 debug_assert_eq!(assoc_item.def_id, def_id);
2368 hir::ItemTrait(.., ref trait_item_refs) => {
2369 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2370 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2373 debug_assert_eq!(assoc_item.def_id, def_id);
2381 span_bug!(parent_item.span,
2382 "unexpected parent of trait or impl item or item not found: {:?}",
2386 /// Calculates the Sized-constraint.
2388 /// In fact, there are only a few options for the types in the constraint:
2389 /// - an obviously-unsized type
2390 /// - a type parameter or projection whose Sizedness can't be known
2391 /// - a tuple of type parameters or projections, if there are multiple
2393 /// - a TyError, if a type contained itself. The representability
2394 /// check should catch this case.
2395 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2397 -> &'tcx [Ty<'tcx>] {
2398 let def = tcx.adt_def(def_id);
2400 let result = tcx.intern_type_list(&def.variants.iter().flat_map(|v| {
2403 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2404 }).collect::<Vec<_>>());
2406 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2411 /// Calculates the dtorck constraint for a type.
2412 fn adt_dtorck_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2414 -> DtorckConstraint<'tcx> {
2415 let def = tcx.adt_def(def_id);
2416 let span = tcx.def_span(def_id);
2417 debug!("dtorck_constraint: {:?}", def);
2419 if def.is_phantom_data() {
2420 let result = DtorckConstraint {
2423 tcx.mk_param_from_def(&tcx.generics_of(def_id).types[0])
2426 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2430 let mut result = def.all_fields()
2431 .map(|field| tcx.type_of(field.did))
2432 .map(|fty| tcx.dtorck_constraint_for_ty(span, fty, 0, fty))
2433 .collect::<Result<DtorckConstraint, ErrorReported>>()
2434 .unwrap_or(DtorckConstraint::empty());
2435 result.outlives.extend(tcx.destructor_constraints(def));
2438 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2443 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2446 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2447 let item = tcx.hir.expect_item(id);
2448 let vec: Vec<_> = match item.node {
2449 hir::ItemTrait(.., ref trait_item_refs) => {
2450 trait_item_refs.iter()
2451 .map(|trait_item_ref| trait_item_ref.id)
2452 .map(|id| tcx.hir.local_def_id(id.node_id))
2455 hir::ItemImpl(.., ref impl_item_refs) => {
2456 impl_item_refs.iter()
2457 .map(|impl_item_ref| impl_item_ref.id)
2458 .map(|id| tcx.hir.local_def_id(id.node_id))
2461 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2466 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
2467 tcx.hir.span_if_local(def_id).unwrap()
2470 /// If the given def ID describes an item belonging to a trait,
2471 /// return the ID of the trait that the trait item belongs to.
2472 /// Otherwise, return `None`.
2473 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
2474 tcx.opt_associated_item(def_id)
2475 .and_then(|associated_item| {
2476 match associated_item.container {
2477 TraitContainer(def_id) => Some(def_id),
2478 ImplContainer(_) => None
2483 /// See `ParamEnv` struct def'n for details.
2484 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2487 // Compute the bounds on Self and the type parameters.
2489 let bounds = tcx.predicates_of(def_id).instantiate_identity(tcx);
2490 let predicates = bounds.predicates;
2492 // Finally, we have to normalize the bounds in the environment, in
2493 // case they contain any associated type projections. This process
2494 // can yield errors if the put in illegal associated types, like
2495 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2496 // report these errors right here; this doesn't actually feel
2497 // right to me, because constructing the environment feels like a
2498 // kind of a "idempotent" action, but I'm not sure where would be
2499 // a better place. In practice, we construct environments for
2500 // every fn once during type checking, and we'll abort if there
2501 // are any errors at that point, so after type checking you can be
2502 // sure that this will succeed without errors anyway.
2504 let unnormalized_env = ty::ParamEnv::new(tcx.intern_predicates(&predicates),
2505 traits::Reveal::UserFacing);
2507 let body_id = tcx.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
2508 tcx.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_id)
2510 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
2511 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
2514 fn crate_disambiguator<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2515 crate_num: CrateNum) -> Symbol {
2516 assert_eq!(crate_num, LOCAL_CRATE);
2517 tcx.sess.local_crate_disambiguator()
2520 fn original_crate_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2521 crate_num: CrateNum) -> Symbol {
2522 assert_eq!(crate_num, LOCAL_CRATE);
2523 tcx.crate_name.clone()
2526 pub fn provide(providers: &mut ty::maps::Providers) {
2527 util::provide(providers);
2528 context::provide(providers);
2529 *providers = ty::maps::Providers {
2531 associated_item_def_ids,
2532 adt_sized_constraint,
2533 adt_dtorck_constraint,
2537 crate_disambiguator,
2538 original_crate_name,
2539 trait_impls_of: trait_def::trait_impls_of_provider,
2544 pub fn provide_extern(providers: &mut ty::maps::Providers) {
2545 *providers = ty::maps::Providers {
2546 adt_sized_constraint,
2547 adt_dtorck_constraint,
2548 trait_impls_of: trait_def::trait_impls_of_provider,
2555 /// A map for the local crate mapping each type to a vector of its
2556 /// inherent impls. This is not meant to be used outside of coherence;
2557 /// rather, you should request the vector for a specific type via
2558 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2559 /// (constructing this map requires touching the entire crate).
2560 #[derive(Clone, Debug)]
2561 pub struct CrateInherentImpls {
2562 pub inherent_impls: DefIdMap<Rc<Vec<DefId>>>,
2565 /// A set of constraints that need to be satisfied in order for
2566 /// a type to be valid for destruction.
2567 #[derive(Clone, Debug)]
2568 pub struct DtorckConstraint<'tcx> {
2569 /// Types that are required to be alive in order for this
2570 /// type to be valid for destruction.
2571 pub outlives: Vec<ty::subst::Kind<'tcx>>,
2572 /// Types that could not be resolved: projections and params.
2573 pub dtorck_types: Vec<Ty<'tcx>>,
2576 impl<'tcx> FromIterator<DtorckConstraint<'tcx>> for DtorckConstraint<'tcx>
2578 fn from_iter<I: IntoIterator<Item=DtorckConstraint<'tcx>>>(iter: I) -> Self {
2579 let mut result = Self::empty();
2581 for constraint in iter {
2582 result.outlives.extend(constraint.outlives);
2583 result.dtorck_types.extend(constraint.dtorck_types);
2591 impl<'tcx> DtorckConstraint<'tcx> {
2592 fn empty() -> DtorckConstraint<'tcx> {
2595 dtorck_types: vec![]
2599 fn dedup<'a>(&mut self) {
2600 let mut outlives = FxHashSet();
2601 let mut dtorck_types = FxHashSet();
2603 self.outlives.retain(|&val| outlives.replace(val).is_none());
2604 self.dtorck_types.retain(|&val| dtorck_types.replace(val).is_none());
2608 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord)]
2609 pub struct SymbolName {
2610 // FIXME: we don't rely on interning or equality here - better have
2611 // this be a `&'tcx str`.
2612 pub name: InternedString
2615 impl Deref for SymbolName {
2618 fn deref(&self) -> &str { &self.name }
2621 impl fmt::Display for SymbolName {
2622 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2623 fmt::Display::fmt(&self.name, fmt)