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::{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, CrateNum)>,
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,
412 const HAS_TY_CLOSURE = 1 << 9,
414 // true if there are "names" of types and regions and so forth
415 // that are local to a particular fn
416 const HAS_LOCAL_NAMES = 1 << 10,
418 // Present if the type belongs in a local type context.
419 // Only set for TyInfer other than Fresh.
420 const KEEP_IN_LOCAL_TCX = 1 << 11,
422 // Is there a projection that does not involve a bound region?
423 // Currently we can't normalize projections w/ bound regions.
424 const HAS_NORMALIZABLE_PROJECTION = 1 << 12,
426 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
427 TypeFlags::HAS_SELF.bits |
428 TypeFlags::HAS_RE_EARLY_BOUND.bits,
430 // Flags representing the nominal content of a type,
431 // computed by FlagsComputation. If you add a new nominal
432 // flag, it should be added here too.
433 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
434 TypeFlags::HAS_SELF.bits |
435 TypeFlags::HAS_TY_INFER.bits |
436 TypeFlags::HAS_RE_INFER.bits |
437 TypeFlags::HAS_RE_SKOL.bits |
438 TypeFlags::HAS_RE_EARLY_BOUND.bits |
439 TypeFlags::HAS_FREE_REGIONS.bits |
440 TypeFlags::HAS_TY_ERR.bits |
441 TypeFlags::HAS_PROJECTION.bits |
442 TypeFlags::HAS_TY_CLOSURE.bits |
443 TypeFlags::HAS_LOCAL_NAMES.bits |
444 TypeFlags::KEEP_IN_LOCAL_TCX.bits,
448 pub struct TyS<'tcx> {
449 pub sty: TypeVariants<'tcx>,
450 pub flags: TypeFlags,
452 // the maximal depth of any bound regions appearing in this type.
456 impl<'tcx> PartialEq for TyS<'tcx> {
458 fn eq(&self, other: &TyS<'tcx>) -> bool {
459 // (self as *const _) == (other as *const _)
460 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
463 impl<'tcx> Eq for TyS<'tcx> {}
465 impl<'tcx> Hash for TyS<'tcx> {
466 fn hash<H: Hasher>(&self, s: &mut H) {
467 (self as *const TyS).hash(s)
471 impl<'tcx> TyS<'tcx> {
472 pub fn is_primitive_ty(&self) -> bool {
474 TypeVariants::TyBool |
475 TypeVariants::TyChar |
476 TypeVariants::TyInt(_) |
477 TypeVariants::TyUint(_) |
478 TypeVariants::TyFloat(_) |
479 TypeVariants::TyInfer(InferTy::IntVar(_)) |
480 TypeVariants::TyInfer(InferTy::FloatVar(_)) |
481 TypeVariants::TyInfer(InferTy::FreshIntTy(_)) |
482 TypeVariants::TyInfer(InferTy::FreshFloatTy(_)) => true,
483 TypeVariants::TyRef(_, x) => x.ty.is_primitive_ty(),
488 pub fn is_suggestable(&self) -> bool {
490 TypeVariants::TyAnon(..) |
491 TypeVariants::TyFnDef(..) |
492 TypeVariants::TyFnPtr(..) |
493 TypeVariants::TyDynamic(..) |
494 TypeVariants::TyClosure(..) |
495 TypeVariants::TyInfer(..) |
496 TypeVariants::TyProjection(..) => false,
502 impl<'a, 'gcx, 'tcx> HashStable<StableHashingContext<'a, 'gcx, 'tcx>> for ty::TyS<'gcx> {
503 fn hash_stable<W: StableHasherResult>(&self,
504 hcx: &mut StableHashingContext<'a, 'gcx, 'tcx>,
505 hasher: &mut StableHasher<W>) {
509 // The other fields just provide fast access to information that is
510 // also contained in `sty`, so no need to hash them.
515 sty.hash_stable(hcx, hasher);
519 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
521 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
522 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
524 /// A wrapper for slices with the additional invariant
525 /// that the slice is interned and no other slice with
526 /// the same contents can exist in the same context.
527 /// This means we can use pointer + length for both
528 /// equality comparisons and hashing.
529 #[derive(Debug, RustcEncodable)]
530 pub struct Slice<T>([T]);
532 impl<T> PartialEq for Slice<T> {
534 fn eq(&self, other: &Slice<T>) -> bool {
535 (&self.0 as *const [T]) == (&other.0 as *const [T])
538 impl<T> Eq for Slice<T> {}
540 impl<T> Hash for Slice<T> {
541 fn hash<H: Hasher>(&self, s: &mut H) {
542 (self.as_ptr(), self.len()).hash(s)
546 impl<T> Deref for Slice<T> {
548 fn deref(&self) -> &[T] {
553 impl<'a, T> IntoIterator for &'a Slice<T> {
555 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
556 fn into_iter(self) -> Self::IntoIter {
561 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {}
564 pub fn empty<'a>() -> &'a Slice<T> {
566 mem::transmute(slice::from_raw_parts(0x1 as *const T, 0))
571 /// Upvars do not get their own node-id. Instead, we use the pair of
572 /// the original var id (that is, the root variable that is referenced
573 /// by the upvar) and the id of the closure expression.
574 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
576 pub var_id: DefIndex,
577 pub closure_expr_id: DefIndex,
580 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
581 pub enum BorrowKind {
582 /// Data must be immutable and is aliasable.
585 /// Data must be immutable but not aliasable. This kind of borrow
586 /// cannot currently be expressed by the user and is used only in
587 /// implicit closure bindings. It is needed when the closure
588 /// is borrowing or mutating a mutable referent, e.g.:
590 /// let x: &mut isize = ...;
591 /// let y = || *x += 5;
593 /// If we were to try to translate this closure into a more explicit
594 /// form, we'd encounter an error with the code as written:
596 /// struct Env { x: & &mut isize }
597 /// let x: &mut isize = ...;
598 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
599 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
601 /// This is then illegal because you cannot mutate a `&mut` found
602 /// in an aliasable location. To solve, you'd have to translate with
603 /// an `&mut` borrow:
605 /// struct Env { x: & &mut isize }
606 /// let x: &mut isize = ...;
607 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
608 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
610 /// Now the assignment to `**env.x` is legal, but creating a
611 /// mutable pointer to `x` is not because `x` is not mutable. We
612 /// could fix this by declaring `x` as `let mut x`. This is ok in
613 /// user code, if awkward, but extra weird for closures, since the
614 /// borrow is hidden.
616 /// So we introduce a "unique imm" borrow -- the referent is
617 /// immutable, but not aliasable. This solves the problem. For
618 /// simplicity, we don't give users the way to express this
619 /// borrow, it's just used when translating closures.
622 /// Data is mutable and not aliasable.
626 /// Information describing the capture of an upvar. This is computed
627 /// during `typeck`, specifically by `regionck`.
628 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
629 pub enum UpvarCapture<'tcx> {
630 /// Upvar is captured by value. This is always true when the
631 /// closure is labeled `move`, but can also be true in other cases
632 /// depending on inference.
635 /// Upvar is captured by reference.
636 ByRef(UpvarBorrow<'tcx>),
639 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
640 pub struct UpvarBorrow<'tcx> {
641 /// The kind of borrow: by-ref upvars have access to shared
642 /// immutable borrows, which are not part of the normal language
644 pub kind: BorrowKind,
646 /// Region of the resulting reference.
647 pub region: ty::Region<'tcx>,
650 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
652 #[derive(Copy, Clone)]
653 pub struct ClosureUpvar<'tcx> {
659 #[derive(Clone, Copy, PartialEq)]
660 pub enum IntVarValue {
662 UintType(ast::UintTy),
665 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
666 pub struct TypeParameterDef {
670 pub has_default: bool,
671 pub object_lifetime_default: ObjectLifetimeDefault,
673 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
674 /// on generic parameter `T`, asserts data behind the parameter
675 /// `T` won't be accessed during the parent type's `Drop` impl.
676 pub pure_wrt_drop: bool,
679 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
680 pub struct RegionParameterDef {
685 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
686 /// on generic parameter `'a`, asserts data of lifetime `'a`
687 /// won't be accessed during the parent type's `Drop` impl.
688 pub pure_wrt_drop: bool,
691 impl RegionParameterDef {
692 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
693 ty::EarlyBoundRegion {
700 pub fn to_bound_region(&self) -> ty::BoundRegion {
701 self.to_early_bound_region_data().to_bound_region()
705 impl ty::EarlyBoundRegion {
706 pub fn to_bound_region(&self) -> ty::BoundRegion {
707 ty::BoundRegion::BrNamed(self.def_id, self.name)
711 /// Information about the formal type/lifetime parameters associated
712 /// with an item or method. Analogous to hir::Generics.
713 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
714 pub struct Generics {
715 pub parent: Option<DefId>,
716 pub parent_regions: u32,
717 pub parent_types: u32,
718 pub regions: Vec<RegionParameterDef>,
719 pub types: Vec<TypeParameterDef>,
721 /// Reverse map to each `TypeParameterDef`'s `index` field, from
722 /// `def_id.index` (`def_id.krate` is the same as the item's).
723 pub type_param_to_index: BTreeMap<DefIndex, u32>,
726 pub has_late_bound_regions: Option<Span>,
730 pub fn parent_count(&self) -> usize {
731 self.parent_regions as usize + self.parent_types as usize
734 pub fn own_count(&self) -> usize {
735 self.regions.len() + self.types.len()
738 pub fn count(&self) -> usize {
739 self.parent_count() + self.own_count()
742 pub fn region_param(&self, param: &EarlyBoundRegion) -> &RegionParameterDef {
743 assert_eq!(self.parent_count(), 0);
744 &self.regions[param.index as usize - self.has_self as usize]
747 pub fn type_param(&self, param: &ParamTy) -> &TypeParameterDef {
748 assert_eq!(self.parent_count(), 0);
749 &self.types[param.idx as usize - self.has_self as usize - self.regions.len()]
753 /// Bounds on generics.
754 #[derive(Clone, Default)]
755 pub struct GenericPredicates<'tcx> {
756 pub parent: Option<DefId>,
757 pub predicates: Vec<Predicate<'tcx>>,
760 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
761 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
763 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
764 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
765 -> InstantiatedPredicates<'tcx> {
766 let mut instantiated = InstantiatedPredicates::empty();
767 self.instantiate_into(tcx, &mut instantiated, substs);
770 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
771 -> InstantiatedPredicates<'tcx> {
772 InstantiatedPredicates {
773 predicates: self.predicates.subst(tcx, substs)
777 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
778 instantiated: &mut InstantiatedPredicates<'tcx>,
779 substs: &Substs<'tcx>) {
780 if let Some(def_id) = self.parent {
781 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
783 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
786 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
787 -> InstantiatedPredicates<'tcx> {
788 let mut instantiated = InstantiatedPredicates::empty();
789 self.instantiate_identity_into(tcx, &mut instantiated);
793 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
794 instantiated: &mut InstantiatedPredicates<'tcx>) {
795 if let Some(def_id) = self.parent {
796 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
798 instantiated.predicates.extend(&self.predicates)
801 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
802 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
803 -> InstantiatedPredicates<'tcx>
805 assert_eq!(self.parent, None);
806 InstantiatedPredicates {
807 predicates: self.predicates.iter().map(|pred| {
808 pred.subst_supertrait(tcx, poly_trait_ref)
814 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
815 pub enum Predicate<'tcx> {
816 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
817 /// the `Self` type of the trait reference and `A`, `B`, and `C`
818 /// would be the type parameters.
819 Trait(PolyTraitPredicate<'tcx>),
821 /// where `T1 == T2`.
822 Equate(PolyEquatePredicate<'tcx>),
825 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
828 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
830 /// where <T as TraitRef>::Name == X, approximately.
831 /// See `ProjectionPredicate` struct for details.
832 Projection(PolyProjectionPredicate<'tcx>),
835 WellFormed(Ty<'tcx>),
837 /// trait must be object-safe
840 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
841 /// for some substitutions `...` and T being a closure type.
842 /// Satisfied (or refuted) once we know the closure's kind.
843 ClosureKind(DefId, ClosureKind),
846 Subtype(PolySubtypePredicate<'tcx>),
849 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
850 /// Performs a substitution suitable for going from a
851 /// poly-trait-ref to supertraits that must hold if that
852 /// poly-trait-ref holds. This is slightly different from a normal
853 /// substitution in terms of what happens with bound regions. See
854 /// lengthy comment below for details.
855 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
856 trait_ref: &ty::PolyTraitRef<'tcx>)
857 -> ty::Predicate<'tcx>
859 // The interaction between HRTB and supertraits is not entirely
860 // obvious. Let me walk you (and myself) through an example.
862 // Let's start with an easy case. Consider two traits:
864 // trait Foo<'a> : Bar<'a,'a> { }
865 // trait Bar<'b,'c> { }
867 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
868 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
869 // knew that `Foo<'x>` (for any 'x) then we also know that
870 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
871 // normal substitution.
873 // In terms of why this is sound, the idea is that whenever there
874 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
875 // holds. So if there is an impl of `T:Foo<'a>` that applies to
876 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
879 // Another example to be careful of is this:
881 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
882 // trait Bar1<'b,'c> { }
884 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
885 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
886 // reason is similar to the previous example: any impl of
887 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
888 // basically we would want to collapse the bound lifetimes from
889 // the input (`trait_ref`) and the supertraits.
891 // To achieve this in practice is fairly straightforward. Let's
892 // consider the more complicated scenario:
894 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
895 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
896 // where both `'x` and `'b` would have a DB index of 1.
897 // The substitution from the input trait-ref is therefore going to be
898 // `'a => 'x` (where `'x` has a DB index of 1).
899 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
900 // early-bound parameter and `'b' is a late-bound parameter with a
902 // - If we replace `'a` with `'x` from the input, it too will have
903 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
904 // just as we wanted.
906 // There is only one catch. If we just apply the substitution `'a
907 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
908 // adjust the DB index because we substituting into a binder (it
909 // tries to be so smart...) resulting in `for<'x> for<'b>
910 // Bar1<'x,'b>` (we have no syntax for this, so use your
911 // imagination). Basically the 'x will have DB index of 2 and 'b
912 // will have DB index of 1. Not quite what we want. So we apply
913 // the substitution to the *contents* of the trait reference,
914 // rather than the trait reference itself (put another way, the
915 // substitution code expects equal binding levels in the values
916 // from the substitution and the value being substituted into, and
917 // this trick achieves that).
919 let substs = &trait_ref.0.substs;
921 Predicate::Trait(ty::Binder(ref data)) =>
922 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
923 Predicate::Equate(ty::Binder(ref data)) =>
924 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
925 Predicate::Subtype(ty::Binder(ref data)) =>
926 Predicate::Subtype(ty::Binder(data.subst(tcx, substs))),
927 Predicate::RegionOutlives(ty::Binder(ref data)) =>
928 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
929 Predicate::TypeOutlives(ty::Binder(ref data)) =>
930 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
931 Predicate::Projection(ty::Binder(ref data)) =>
932 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
933 Predicate::WellFormed(data) =>
934 Predicate::WellFormed(data.subst(tcx, substs)),
935 Predicate::ObjectSafe(trait_def_id) =>
936 Predicate::ObjectSafe(trait_def_id),
937 Predicate::ClosureKind(closure_def_id, kind) =>
938 Predicate::ClosureKind(closure_def_id, kind),
943 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
944 pub struct TraitPredicate<'tcx> {
945 pub trait_ref: TraitRef<'tcx>
947 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
949 impl<'tcx> TraitPredicate<'tcx> {
950 pub fn def_id(&self) -> DefId {
951 self.trait_ref.def_id
954 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
955 self.trait_ref.input_types()
958 pub fn self_ty(&self) -> Ty<'tcx> {
959 self.trait_ref.self_ty()
963 impl<'tcx> PolyTraitPredicate<'tcx> {
964 pub fn def_id(&self) -> DefId {
965 // ok to skip binder since trait def-id does not care about regions
970 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
971 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
972 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
974 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
975 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
976 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
977 pub type PolyRegionOutlivesPredicate<'tcx> = PolyOutlivesPredicate<ty::Region<'tcx>,
979 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
981 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
982 pub struct SubtypePredicate<'tcx> {
983 pub a_is_expected: bool,
987 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
989 /// This kind of predicate has no *direct* correspondent in the
990 /// syntax, but it roughly corresponds to the syntactic forms:
992 /// 1. `T : TraitRef<..., Item=Type>`
993 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
995 /// In particular, form #1 is "desugared" to the combination of a
996 /// normal trait predicate (`T : TraitRef<...>`) and one of these
997 /// predicates. Form #2 is a broader form in that it also permits
998 /// equality between arbitrary types. Processing an instance of Form
999 /// #2 eventually yields one of these `ProjectionPredicate`
1000 /// instances to normalize the LHS.
1001 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1002 pub struct ProjectionPredicate<'tcx> {
1003 pub projection_ty: ProjectionTy<'tcx>,
1007 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1009 impl<'tcx> PolyProjectionPredicate<'tcx> {
1010 pub fn to_poly_trait_ref(&self, tcx: TyCtxt) -> PolyTraitRef<'tcx> {
1011 // Note: unlike with TraitRef::to_poly_trait_ref(),
1012 // self.0.trait_ref is permitted to have escaping regions.
1013 // This is because here `self` has a `Binder` and so does our
1014 // return value, so we are preserving the number of binding
1016 ty::Binder(self.0.projection_ty.trait_ref(tcx))
1020 pub trait ToPolyTraitRef<'tcx> {
1021 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1024 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1025 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1026 assert!(!self.has_escaping_regions());
1027 ty::Binder(self.clone())
1031 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1032 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1033 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1037 pub trait ToPredicate<'tcx> {
1038 fn to_predicate(&self) -> Predicate<'tcx>;
1041 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1042 fn to_predicate(&self) -> Predicate<'tcx> {
1043 // we're about to add a binder, so let's check that we don't
1044 // accidentally capture anything, or else that might be some
1045 // weird debruijn accounting.
1046 assert!(!self.has_escaping_regions());
1048 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
1049 trait_ref: self.clone()
1054 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1055 fn to_predicate(&self) -> Predicate<'tcx> {
1056 ty::Predicate::Trait(self.to_poly_trait_predicate())
1060 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
1061 fn to_predicate(&self) -> Predicate<'tcx> {
1062 Predicate::Equate(self.clone())
1066 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1067 fn to_predicate(&self) -> Predicate<'tcx> {
1068 Predicate::RegionOutlives(self.clone())
1072 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1073 fn to_predicate(&self) -> Predicate<'tcx> {
1074 Predicate::TypeOutlives(self.clone())
1078 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1079 fn to_predicate(&self) -> Predicate<'tcx> {
1080 Predicate::Projection(self.clone())
1084 impl<'tcx> Predicate<'tcx> {
1085 /// Iterates over the types in this predicate. Note that in all
1086 /// cases this is skipping over a binder, so late-bound regions
1087 /// with depth 0 are bound by the predicate.
1088 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1089 let vec: Vec<_> = match *self {
1090 ty::Predicate::Trait(ref data) => {
1091 data.skip_binder().input_types().collect()
1093 ty::Predicate::Equate(ty::Binder(ref data)) => {
1094 vec![data.0, data.1]
1096 ty::Predicate::Subtype(ty::Binder(SubtypePredicate { a, b, a_is_expected: _ })) => {
1099 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
1102 ty::Predicate::RegionOutlives(..) => {
1105 ty::Predicate::Projection(ref data) => {
1106 data.0.projection_ty.substs.types().chain(Some(data.0.ty)).collect()
1108 ty::Predicate::WellFormed(data) => {
1111 ty::Predicate::ObjectSafe(_trait_def_id) => {
1114 ty::Predicate::ClosureKind(_closure_def_id, _kind) => {
1119 // The only reason to collect into a vector here is that I was
1120 // too lazy to make the full (somewhat complicated) iterator
1121 // type that would be needed here. But I wanted this fn to
1122 // return an iterator conceptually, rather than a `Vec`, so as
1123 // to be closer to `Ty::walk`.
1127 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1129 Predicate::Trait(ref t) => {
1130 Some(t.to_poly_trait_ref())
1132 Predicate::Projection(..) |
1133 Predicate::Equate(..) |
1134 Predicate::Subtype(..) |
1135 Predicate::RegionOutlives(..) |
1136 Predicate::WellFormed(..) |
1137 Predicate::ObjectSafe(..) |
1138 Predicate::ClosureKind(..) |
1139 Predicate::TypeOutlives(..) => {
1146 /// Represents the bounds declared on a particular set of type
1147 /// parameters. Should eventually be generalized into a flag list of
1148 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1149 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1150 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1151 /// the `GenericPredicates` are expressed in terms of the bound type
1152 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1153 /// represented a set of bounds for some particular instantiation,
1154 /// meaning that the generic parameters have been substituted with
1159 /// struct Foo<T,U:Bar<T>> { ... }
1161 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1162 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1163 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1164 /// [usize:Bar<isize>]]`.
1166 pub struct InstantiatedPredicates<'tcx> {
1167 pub predicates: Vec<Predicate<'tcx>>,
1170 impl<'tcx> InstantiatedPredicates<'tcx> {
1171 pub fn empty() -> InstantiatedPredicates<'tcx> {
1172 InstantiatedPredicates { predicates: vec![] }
1175 pub fn is_empty(&self) -> bool {
1176 self.predicates.is_empty()
1180 /// When type checking, we use the `ParamEnv` to track
1181 /// details about the set of where-clauses that are in scope at this
1182 /// particular point.
1183 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1184 pub struct ParamEnv<'tcx> {
1185 /// Obligations that the caller must satisfy. This is basically
1186 /// the set of bounds on the in-scope type parameters, translated
1187 /// into Obligations, and elaborated and normalized.
1188 pub caller_bounds: &'tcx Slice<ty::Predicate<'tcx>>,
1190 /// Typically, this is `Reveal::UserFacing`, but during trans we
1191 /// want `Reveal::All` -- note that this is always paired with an
1192 /// empty environment. To get that, use `ParamEnv::reveal()`.
1193 pub reveal: traits::Reveal,
1196 impl<'tcx> ParamEnv<'tcx> {
1197 /// Creates a suitable environment in which to perform trait
1198 /// queries on the given value. This will either be `self` *or*
1199 /// the empty environment, depending on whether `value` references
1200 /// type parameters that are in scope. (If it doesn't, then any
1201 /// judgements should be completely independent of the context,
1202 /// and hence we can safely use the empty environment so as to
1203 /// enable more sharing across functions.)
1205 /// NB: This is a mildly dubious thing to do, in that a function
1206 /// (or other environment) might have wacky where-clauses like
1207 /// `where Box<u32>: Copy`, which are clearly never
1208 /// satisfiable. The code will at present ignore these,
1209 /// effectively, when type-checking the body of said
1210 /// function. This preserves existing behavior in any
1211 /// case. --nmatsakis
1212 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1213 assert!(!value.needs_infer());
1214 if value.has_param_types() || value.has_self_ty() {
1221 param_env: ParamEnv::empty(self.reveal),
1228 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1229 pub struct ParamEnvAnd<'tcx, T> {
1230 pub param_env: ParamEnv<'tcx>,
1234 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1235 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1236 (self.param_env, self.value)
1240 #[derive(Copy, Clone, Debug)]
1241 pub struct Destructor {
1242 /// The def-id of the destructor method
1247 flags AdtFlags: u32 {
1248 const NO_ADT_FLAGS = 0,
1249 const IS_ENUM = 1 << 0,
1250 const IS_PHANTOM_DATA = 1 << 1,
1251 const IS_FUNDAMENTAL = 1 << 2,
1252 const IS_UNION = 1 << 3,
1253 const IS_BOX = 1 << 4,
1258 pub struct VariantDef {
1259 /// The variant's DefId. If this is a tuple-like struct,
1260 /// this is the DefId of the struct's ctor.
1262 pub name: Name, // struct's name if this is a struct
1263 pub discr: VariantDiscr,
1264 pub fields: Vec<FieldDef>,
1265 pub ctor_kind: CtorKind,
1268 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1269 pub enum VariantDiscr {
1270 /// Explicit value for this variant, i.e. `X = 123`.
1271 /// The `DefId` corresponds to the embedded constant.
1274 /// The previous variant's discriminant plus one.
1275 /// For efficiency reasons, the distance from the
1276 /// last `Explicit` discriminant is being stored,
1277 /// or `0` for the first variant, if it has none.
1282 pub struct FieldDef {
1285 pub vis: Visibility,
1288 /// The definition of an abstract data type - a struct or enum.
1290 /// These are all interned (by intern_adt_def) into the adt_defs
1294 pub variants: Vec<VariantDef>,
1296 pub repr: ReprOptions,
1299 impl PartialEq for AdtDef {
1300 // AdtDef are always interned and this is part of TyS equality
1302 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1305 impl Eq for AdtDef {}
1307 impl Hash for AdtDef {
1309 fn hash<H: Hasher>(&self, s: &mut H) {
1310 (self as *const AdtDef).hash(s)
1314 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1315 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1320 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1323 impl<'a, 'gcx, 'tcx> HashStable<StableHashingContext<'a, 'gcx, 'tcx>> for AdtDef {
1324 fn hash_stable<W: StableHasherResult>(&self,
1325 hcx: &mut StableHashingContext<'a, 'gcx, 'tcx>,
1326 hasher: &mut StableHasher<W>) {
1334 did.hash_stable(hcx, hasher);
1335 variants.hash_stable(hcx, hasher);
1336 flags.hash_stable(hcx, hasher);
1337 repr.hash_stable(hcx, hasher);
1341 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1342 pub enum AdtKind { Struct, Union, Enum }
1345 #[derive(RustcEncodable, RustcDecodable, Default)]
1346 flags ReprFlags: u8 {
1347 const IS_C = 1 << 0,
1348 const IS_PACKED = 1 << 1,
1349 const IS_SIMD = 1 << 2,
1350 // Internal only for now. If true, don't reorder fields.
1351 const IS_LINEAR = 1 << 3,
1353 // Any of these flags being set prevent field reordering optimisation.
1354 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1355 ReprFlags::IS_PACKED.bits |
1356 ReprFlags::IS_SIMD.bits |
1357 ReprFlags::IS_LINEAR.bits,
1361 impl_stable_hash_for!(struct ReprFlags {
1367 /// Represents the repr options provided by the user,
1368 #[derive(Copy, Clone, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1369 pub struct ReprOptions {
1370 pub int: Option<attr::IntType>,
1372 pub flags: ReprFlags,
1375 impl_stable_hash_for!(struct ReprOptions {
1382 pub fn new(tcx: TyCtxt, did: DefId) -> ReprOptions {
1383 let mut flags = ReprFlags::empty();
1384 let mut size = None;
1385 let mut max_align = 0;
1386 for attr in tcx.get_attrs(did).iter() {
1387 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1388 flags.insert(match r {
1389 attr::ReprExtern => ReprFlags::IS_C,
1390 attr::ReprPacked => ReprFlags::IS_PACKED,
1391 attr::ReprSimd => ReprFlags::IS_SIMD,
1392 attr::ReprInt(i) => {
1396 attr::ReprAlign(align) => {
1397 max_align = cmp::max(align, max_align);
1404 // FIXME(eddyb) This is deprecated and should be removed.
1405 if tcx.has_attr(did, "simd") {
1406 flags.insert(ReprFlags::IS_SIMD);
1409 // This is here instead of layout because the choice must make it into metadata.
1410 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1411 flags.insert(ReprFlags::IS_LINEAR);
1413 ReprOptions { int: size, align: max_align, flags: flags }
1417 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1419 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1421 pub fn packed(&self) -> bool { self.flags.contains(ReprFlags::IS_PACKED) }
1423 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1425 pub fn discr_type(&self) -> attr::IntType {
1426 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Is))
1429 /// Returns true if this `#[repr()]` should inhabit "smart enum
1430 /// layout" optimizations, such as representing `Foo<&T>` as a
1432 pub fn inhibit_enum_layout_opt(&self) -> bool {
1433 self.c() || self.int.is_some()
1437 impl<'a, 'gcx, 'tcx> AdtDef {
1441 variants: Vec<VariantDef>,
1442 repr: ReprOptions) -> Self {
1443 let mut flags = AdtFlags::NO_ADT_FLAGS;
1444 let attrs = tcx.get_attrs(did);
1445 if attr::contains_name(&attrs, "fundamental") {
1446 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1448 if Some(did) == tcx.lang_items.phantom_data() {
1449 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1451 if Some(did) == tcx.lang_items.owned_box() {
1452 flags = flags | AdtFlags::IS_BOX;
1455 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
1456 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
1457 AdtKind::Struct => {}
1468 pub fn is_struct(&self) -> bool {
1469 !self.is_union() && !self.is_enum()
1473 pub fn is_union(&self) -> bool {
1474 self.flags.intersects(AdtFlags::IS_UNION)
1478 pub fn is_enum(&self) -> bool {
1479 self.flags.intersects(AdtFlags::IS_ENUM)
1482 /// Returns the kind of the ADT - Struct or Enum.
1484 pub fn adt_kind(&self) -> AdtKind {
1487 } else if self.is_union() {
1494 pub fn descr(&self) -> &'static str {
1495 match self.adt_kind() {
1496 AdtKind::Struct => "struct",
1497 AdtKind::Union => "union",
1498 AdtKind::Enum => "enum",
1502 pub fn variant_descr(&self) -> &'static str {
1503 match self.adt_kind() {
1504 AdtKind::Struct => "struct",
1505 AdtKind::Union => "union",
1506 AdtKind::Enum => "variant",
1510 /// Returns whether this type is #[fundamental] for the purposes
1511 /// of coherence checking.
1513 pub fn is_fundamental(&self) -> bool {
1514 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
1517 /// Returns true if this is PhantomData<T>.
1519 pub fn is_phantom_data(&self) -> bool {
1520 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
1523 /// Returns true if this is Box<T>.
1525 pub fn is_box(&self) -> bool {
1526 self.flags.intersects(AdtFlags::IS_BOX)
1529 /// Returns whether this type has a destructor.
1530 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
1531 self.destructor(tcx).is_some()
1534 /// Asserts this is a struct and returns the struct's unique
1536 pub fn struct_variant(&self) -> &VariantDef {
1537 assert!(!self.is_enum());
1542 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
1543 tcx.predicates_of(self.did)
1546 /// Returns an iterator over all fields contained
1549 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
1550 self.variants.iter().flat_map(|v| v.fields.iter())
1554 pub fn is_univariant(&self) -> bool {
1555 self.variants.len() == 1
1558 pub fn is_payloadfree(&self) -> bool {
1559 !self.variants.is_empty() &&
1560 self.variants.iter().all(|v| v.fields.is_empty())
1563 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
1566 .find(|v| v.did == vid)
1567 .expect("variant_with_id: unknown variant")
1570 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1573 .position(|v| v.did == vid)
1574 .expect("variant_index_with_id: unknown variant")
1577 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
1579 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
1580 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
1581 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.struct_variant(),
1582 _ => bug!("unexpected def {:?} in variant_of_def", def)
1587 pub fn discriminants(&'a self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1588 -> impl Iterator<Item=ConstInt> + 'a {
1589 let param_env = ParamEnv::empty(traits::Reveal::UserFacing);
1590 let repr_type = self.repr.discr_type();
1591 let initial = repr_type.initial_discriminant(tcx.global_tcx());
1592 let mut prev_discr = None::<ConstInt>;
1593 self.variants.iter().map(move |v| {
1594 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr());
1595 if let VariantDiscr::Explicit(expr_did) = v.discr {
1596 let substs = Substs::identity_for_item(tcx.global_tcx(), expr_did);
1597 match tcx.const_eval(param_env.and((expr_did, substs))) {
1598 Ok(ConstVal::Integral(v)) => {
1602 if !expr_did.is_local() {
1603 span_bug!(tcx.def_span(expr_did),
1604 "variant discriminant evaluation succeeded \
1605 in its crate but failed locally: {:?}", err);
1610 prev_discr = Some(discr);
1616 /// Compute the discriminant value used by a specific variant.
1617 /// Unlike `discriminants`, this is (amortized) constant-time,
1618 /// only doing at most one query for evaluating an explicit
1619 /// discriminant (the last one before the requested variant),
1620 /// assuming there are no constant-evaluation errors there.
1621 pub fn discriminant_for_variant(&self,
1622 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1623 variant_index: usize)
1625 let param_env = ParamEnv::empty(traits::Reveal::UserFacing);
1626 let repr_type = self.repr.discr_type();
1627 let mut explicit_value = repr_type.initial_discriminant(tcx.global_tcx());
1628 let mut explicit_index = variant_index;
1630 match self.variants[explicit_index].discr {
1631 ty::VariantDiscr::Relative(0) => break,
1632 ty::VariantDiscr::Relative(distance) => {
1633 explicit_index -= distance;
1635 ty::VariantDiscr::Explicit(expr_did) => {
1636 let substs = Substs::identity_for_item(tcx.global_tcx(), expr_did);
1637 match tcx.const_eval(param_env.and((expr_did, substs))) {
1638 Ok(ConstVal::Integral(v)) => {
1643 if !expr_did.is_local() {
1644 span_bug!(tcx.def_span(expr_did),
1645 "variant discriminant evaluation succeeded \
1646 in its crate but failed locally: {:?}", err);
1648 if explicit_index == 0 {
1651 explicit_index -= 1;
1657 let discr = explicit_value.to_u128_unchecked()
1658 .wrapping_add((variant_index - explicit_index) as u128);
1660 attr::UnsignedInt(ty) => {
1661 ConstInt::new_unsigned_truncating(discr, ty,
1662 tcx.sess.target.uint_type)
1664 attr::SignedInt(ty) => {
1665 ConstInt::new_signed_truncating(discr as i128, ty,
1666 tcx.sess.target.int_type)
1671 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
1672 tcx.adt_destructor(self.did)
1675 /// Returns a list of types such that `Self: Sized` if and only
1676 /// if that type is Sized, or `TyErr` if this type is recursive.
1678 /// Oddly enough, checking that the sized-constraint is Sized is
1679 /// actually more expressive than checking all members:
1680 /// the Sized trait is inductive, so an associated type that references
1681 /// Self would prevent its containing ADT from being Sized.
1683 /// Due to normalization being eager, this applies even if
1684 /// the associated type is behind a pointer, e.g. issue #31299.
1685 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
1686 match queries::adt_sized_constraint::try_get(tcx, DUMMY_SP, self.did) {
1689 debug!("adt_sized_constraint: {:?} is recursive", self);
1690 // This should be reported as an error by `check_representable`.
1692 // Consider the type as Sized in the meanwhile to avoid
1693 // further errors. Delay our `bug` diagnostic here to get
1694 // emitted later as well in case we accidentally otherwise don't
1697 tcx.intern_type_list(&[tcx.types.err])
1702 fn sized_constraint_for_ty(&self,
1703 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1706 let result = match ty.sty {
1707 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
1708 TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
1709 TyArray(..) | TyClosure(..) | TyNever => {
1713 TyStr | TyDynamic(..) | TySlice(_) | TyError => {
1714 // these are never sized - return the target type
1718 TyTuple(ref tys, _) => {
1721 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
1725 TyAdt(adt, substs) => {
1727 let adt_tys = adt.sized_constraint(tcx);
1728 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
1731 .map(|ty| ty.subst(tcx, substs))
1732 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
1736 TyProjection(..) | TyAnon(..) => {
1737 // must calculate explicitly.
1738 // FIXME: consider special-casing always-Sized projections
1743 // perf hack: if there is a `T: Sized` bound, then
1744 // we know that `T` is Sized and do not need to check
1747 let sized_trait = match tcx.lang_items.sized_trait() {
1749 _ => return vec![ty]
1751 let sized_predicate = Binder(TraitRef {
1752 def_id: sized_trait,
1753 substs: tcx.mk_substs_trait(ty, &[])
1755 let predicates = tcx.predicates_of(self.did).predicates;
1756 if predicates.into_iter().any(|p| p == sized_predicate) {
1764 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
1768 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
1773 impl<'a, 'gcx, 'tcx> VariantDef {
1775 pub fn find_field_named(&self, name: ast::Name) -> Option<&FieldDef> {
1776 self.index_of_field_named(name).map(|index| &self.fields[index])
1779 pub fn index_of_field_named(&self, name: ast::Name) -> Option<usize> {
1780 if let Some(index) = self.fields.iter().position(|f| f.name == name) {
1783 let mut ident = name.to_ident();
1784 while ident.ctxt != SyntaxContext::empty() {
1785 ident.ctxt.remove_mark();
1786 if let Some(field) = self.fields.iter().position(|f| f.name.to_ident() == ident) {
1794 pub fn field_named(&self, name: ast::Name) -> &FieldDef {
1795 self.find_field_named(name).unwrap()
1799 impl<'a, 'gcx, 'tcx> FieldDef {
1800 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1801 tcx.type_of(self.did).subst(tcx, subst)
1805 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1806 pub enum ClosureKind {
1807 // Warning: Ordering is significant here! The ordering is chosen
1808 // because the trait Fn is a subtrait of FnMut and so in turn, and
1809 // hence we order it so that Fn < FnMut < FnOnce.
1815 impl<'a, 'tcx> ClosureKind {
1816 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
1818 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
1819 ClosureKind::FnMut => {
1820 tcx.require_lang_item(FnMutTraitLangItem)
1822 ClosureKind::FnOnce => {
1823 tcx.require_lang_item(FnOnceTraitLangItem)
1828 /// True if this a type that impls this closure kind
1829 /// must also implement `other`.
1830 pub fn extends(self, other: ty::ClosureKind) -> bool {
1831 match (self, other) {
1832 (ClosureKind::Fn, ClosureKind::Fn) => true,
1833 (ClosureKind::Fn, ClosureKind::FnMut) => true,
1834 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
1835 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
1836 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
1837 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
1843 impl<'tcx> TyS<'tcx> {
1844 /// Iterator that walks `self` and any types reachable from
1845 /// `self`, in depth-first order. Note that just walks the types
1846 /// that appear in `self`, it does not descend into the fields of
1847 /// structs or variants. For example:
1850 /// isize => { isize }
1851 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
1852 /// [isize] => { [isize], isize }
1854 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
1855 TypeWalker::new(self)
1858 /// Iterator that walks the immediate children of `self`. Hence
1859 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
1860 /// (but not `i32`, like `walk`).
1861 pub fn walk_shallow(&'tcx self) -> AccIntoIter<walk::TypeWalkerArray<'tcx>> {
1862 walk::walk_shallow(self)
1865 /// Walks `ty` and any types appearing within `ty`, invoking the
1866 /// callback `f` on each type. If the callback returns false, then the
1867 /// children of the current type are ignored.
1869 /// Note: prefer `ty.walk()` where possible.
1870 pub fn maybe_walk<F>(&'tcx self, mut f: F)
1871 where F : FnMut(Ty<'tcx>) -> bool
1873 let mut walker = self.walk();
1874 while let Some(ty) = walker.next() {
1876 walker.skip_current_subtree();
1882 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1883 pub enum LvaluePreference {
1888 impl LvaluePreference {
1889 pub fn from_mutbl(m: hir::Mutability) -> Self {
1891 hir::MutMutable => PreferMutLvalue,
1892 hir::MutImmutable => NoPreference,
1898 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
1900 hir::MutMutable => MutBorrow,
1901 hir::MutImmutable => ImmBorrow,
1905 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
1906 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
1907 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
1909 pub fn to_mutbl_lossy(self) -> hir::Mutability {
1911 MutBorrow => hir::MutMutable,
1912 ImmBorrow => hir::MutImmutable,
1914 // We have no type corresponding to a unique imm borrow, so
1915 // use `&mut`. It gives all the capabilities of an `&uniq`
1916 // and hence is a safe "over approximation".
1917 UniqueImmBorrow => hir::MutMutable,
1921 pub fn to_user_str(&self) -> &'static str {
1923 MutBorrow => "mutable",
1924 ImmBorrow => "immutable",
1925 UniqueImmBorrow => "uniquely immutable",
1930 #[derive(Debug, Clone)]
1931 pub enum Attributes<'gcx> {
1932 Owned(Rc<[ast::Attribute]>),
1933 Borrowed(&'gcx [ast::Attribute])
1936 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
1937 type Target = [ast::Attribute];
1939 fn deref(&self) -> &[ast::Attribute] {
1941 &Attributes::Owned(ref data) => &data,
1942 &Attributes::Borrowed(data) => data
1947 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
1948 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
1949 self.typeck_tables_of(self.hir.body_owner_def_id(body))
1952 /// Returns an iterator of the def-ids for all body-owners in this
1953 /// crate. If you would prefer to iterate over the bodies
1954 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
1955 pub fn body_owners(self) -> impl Iterator<Item = DefId> + 'a {
1959 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
1962 pub fn expr_span(self, id: NodeId) -> Span {
1963 match self.hir.find(id) {
1964 Some(hir_map::NodeExpr(e)) => {
1968 bug!("Node id {} is not an expr: {:?}", id, f);
1971 bug!("Node id {} is not present in the node map", id);
1976 pub fn local_var_name_str(self, id: NodeId) -> InternedString {
1977 match self.hir.find(id) {
1978 Some(hir_map::NodeBinding(pat)) => {
1980 hir::PatKind::Binding(_, _, ref path1, _) => path1.node.as_str(),
1982 bug!("Variable id {} maps to {:?}, not local", id, pat);
1986 r => bug!("Variable id {} maps to {:?}, not local", id, r),
1990 pub fn local_var_name_str_def_index(self, def_index: DefIndex) -> InternedString {
1991 let node_id = self.hir.as_local_node_id(DefId::local(def_index)).unwrap();
1992 self.local_var_name_str(node_id)
1995 pub fn expr_is_lval(self, expr: &hir::Expr) -> bool {
1997 hir::ExprPath(hir::QPath::Resolved(_, ref path)) => {
1999 Def::Local(..) | Def::Upvar(..) | Def::Static(..) | Def::Err => true,
2004 hir::ExprType(ref e, _) => {
2005 self.expr_is_lval(e)
2008 hir::ExprUnary(hir::UnDeref, _) |
2009 hir::ExprField(..) |
2010 hir::ExprTupField(..) |
2011 hir::ExprIndex(..) => {
2015 // Partially qualified paths in expressions can only legally
2016 // refer to associated items which are always rvalues.
2017 hir::ExprPath(hir::QPath::TypeRelative(..)) |
2020 hir::ExprMethodCall(..) |
2021 hir::ExprStruct(..) |
2024 hir::ExprMatch(..) |
2025 hir::ExprClosure(..) |
2026 hir::ExprBlock(..) |
2027 hir::ExprRepeat(..) |
2028 hir::ExprArray(..) |
2029 hir::ExprBreak(..) |
2030 hir::ExprAgain(..) |
2032 hir::ExprWhile(..) |
2034 hir::ExprAssign(..) |
2035 hir::ExprInlineAsm(..) |
2036 hir::ExprAssignOp(..) |
2038 hir::ExprUnary(..) |
2040 hir::ExprAddrOf(..) |
2041 hir::ExprBinary(..) |
2042 hir::ExprCast(..) => {
2048 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2049 self.associated_items(id)
2050 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2054 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2055 self.associated_items(did).any(|item| {
2056 item.relevant_for_never()
2060 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2061 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2062 match self.hir.get(node_id) {
2063 hir_map::NodeTraitItem(_) | hir_map::NodeImplItem(_) => true,
2067 match self.describe_def(def_id).expect("no def for def-id") {
2068 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2073 if is_associated_item {
2074 Some(self.associated_item(def_id))
2080 fn associated_item_from_trait_item_ref(self,
2081 parent_def_id: DefId,
2082 parent_vis: &hir::Visibility,
2083 trait_item_ref: &hir::TraitItemRef)
2085 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2086 let (kind, has_self) = match trait_item_ref.kind {
2087 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2088 hir::AssociatedItemKind::Method { has_self } => {
2089 (ty::AssociatedKind::Method, has_self)
2091 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2095 name: trait_item_ref.name,
2097 // Visibility of trait items is inherited from their traits.
2098 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2099 defaultness: trait_item_ref.defaultness,
2101 container: TraitContainer(parent_def_id),
2102 method_has_self_argument: has_self
2106 fn associated_item_from_impl_item_ref(self,
2107 parent_def_id: DefId,
2108 impl_item_ref: &hir::ImplItemRef)
2110 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2111 let (kind, has_self) = match impl_item_ref.kind {
2112 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2113 hir::AssociatedItemKind::Method { has_self } => {
2114 (ty::AssociatedKind::Method, has_self)
2116 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2119 ty::AssociatedItem {
2120 name: impl_item_ref.name,
2122 // Visibility of trait impl items doesn't matter.
2123 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2124 defaultness: impl_item_ref.defaultness,
2126 container: ImplContainer(parent_def_id),
2127 method_has_self_argument: has_self
2131 #[inline] // FIXME(#35870) Avoid closures being unexported due to impl Trait.
2132 pub fn associated_items(self, def_id: DefId)
2133 -> impl Iterator<Item = ty::AssociatedItem> + 'a {
2134 let def_ids = self.associated_item_def_ids(def_id);
2135 (0..def_ids.len()).map(move |i| self.associated_item(def_ids[i]))
2138 /// Returns true if the impls are the same polarity and are implementing
2139 /// a trait which contains no items
2140 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2141 if !self.sess.features.borrow().overlapping_marker_traits {
2144 let trait1_is_empty = self.impl_trait_ref(def_id1)
2145 .map_or(false, |trait_ref| {
2146 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2148 let trait2_is_empty = self.impl_trait_ref(def_id2)
2149 .map_or(false, |trait_ref| {
2150 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2152 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2157 // Returns `ty::VariantDef` if `def` refers to a struct,
2158 // or variant or their constructors, panics otherwise.
2159 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2161 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2162 let enum_did = self.parent_def_id(did).unwrap();
2163 self.adt_def(enum_did).variant_with_id(did)
2165 Def::Struct(did) | Def::Union(did) => {
2166 self.adt_def(did).struct_variant()
2168 Def::StructCtor(ctor_did, ..) => {
2169 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2170 self.adt_def(did).struct_variant()
2172 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2176 pub fn def_key(self, id: DefId) -> hir_map::DefKey {
2178 self.hir.def_key(id)
2180 self.sess.cstore.def_key(id)
2184 /// Convert a `DefId` into its fully expanded `DefPath` (every
2185 /// `DefId` is really just an interned def-path).
2187 /// Note that if `id` is not local to this crate, the result will
2188 /// be a non-local `DefPath`.
2189 pub fn def_path(self, id: DefId) -> hir_map::DefPath {
2191 self.hir.def_path(id)
2193 self.sess.cstore.def_path(id)
2198 pub fn def_path_hash(self, def_id: DefId) -> hir_map::DefPathHash {
2199 if def_id.is_local() {
2200 self.hir.definitions().def_path_hash(def_id.index)
2202 self.sess.cstore.def_path_hash(def_id)
2206 pub fn item_name(self, id: DefId) -> ast::Name {
2207 if let Some(id) = self.hir.as_local_node_id(id) {
2209 } else if id.index == CRATE_DEF_INDEX {
2210 self.sess.cstore.original_crate_name(id.krate)
2212 let def_key = self.sess.cstore.def_key(id);
2213 // The name of a StructCtor is that of its struct parent.
2214 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2215 self.item_name(DefId {
2217 index: def_key.parent.unwrap()
2220 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2221 bug!("item_name: no name for {:?}", self.def_path(id));
2227 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2228 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2232 ty::InstanceDef::Item(did) => {
2233 self.optimized_mir(did)
2235 ty::InstanceDef::Intrinsic(..) |
2236 ty::InstanceDef::FnPtrShim(..) |
2237 ty::InstanceDef::Virtual(..) |
2238 ty::InstanceDef::ClosureOnceShim { .. } |
2239 ty::InstanceDef::DropGlue(..) |
2240 ty::InstanceDef::CloneShim(..) => {
2241 self.mir_shims(instance)
2246 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2247 /// Returns None if there is no MIR for the DefId
2248 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2249 if self.is_mir_available(did) {
2250 Some(self.optimized_mir(did))
2256 /// Get the attributes of a definition.
2257 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2258 if let Some(id) = self.hir.as_local_node_id(did) {
2259 Attributes::Borrowed(self.hir.attrs(id))
2261 Attributes::Owned(self.item_attrs(did))
2265 /// Determine whether an item is annotated with an attribute
2266 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2267 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2270 pub fn trait_has_default_impl(self, trait_def_id: DefId) -> bool {
2271 self.trait_def(trait_def_id).has_default_impl
2274 /// Given the def_id of an impl, return the def_id of the trait it implements.
2275 /// If it implements no trait, return `None`.
2276 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2277 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2280 /// If the given def ID describes a method belonging to an impl, return the
2281 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2282 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2283 let item = if def_id.krate != LOCAL_CRATE {
2284 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2285 Some(self.associated_item(def_id))
2290 self.opt_associated_item(def_id)
2294 Some(trait_item) => {
2295 match trait_item.container {
2296 TraitContainer(_) => None,
2297 ImplContainer(def_id) => Some(def_id),
2304 pub fn node_scope_region(self, id: NodeId) -> Region<'tcx> {
2305 self.mk_region(ty::ReScope(CodeExtent::Misc(id)))
2308 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2309 /// with the name of the crate containing the impl.
2310 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2311 if impl_did.is_local() {
2312 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2313 Ok(self.hir.span(node_id))
2315 Err(self.sess.cstore.crate_name(impl_did.krate))
2319 pub fn adjust(self, name: Name, scope: DefId, block: NodeId) -> (Ident, DefId) {
2320 self.adjust_ident(name.to_ident(), scope, block)
2323 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
2324 let expansion = match scope.krate {
2325 LOCAL_CRATE => self.hir.definitions().expansion(scope.index),
2328 let scope = match ident.ctxt.adjust(expansion) {
2329 Some(macro_def) => self.hir.definitions().macro_def_scope(macro_def),
2330 None => self.hir.get_module_parent(block),
2336 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2337 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2338 F: FnOnce(&[hir::Freevar]) -> T,
2340 match self.freevars.borrow().get(&fid) {
2342 Some(d) => f(&d[..])
2347 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
2350 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2351 let parent_id = tcx.hir.get_parent(id);
2352 let parent_def_id = tcx.hir.local_def_id(parent_id);
2353 let parent_item = tcx.hir.expect_item(parent_id);
2354 match parent_item.node {
2355 hir::ItemImpl(.., ref impl_item_refs) => {
2356 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2357 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2359 debug_assert_eq!(assoc_item.def_id, def_id);
2364 hir::ItemTrait(.., ref trait_item_refs) => {
2365 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2366 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2369 debug_assert_eq!(assoc_item.def_id, def_id);
2377 span_bug!(parent_item.span,
2378 "unexpected parent of trait or impl item or item not found: {:?}",
2382 /// Calculates the Sized-constraint.
2384 /// In fact, there are only a few options for the types in the constraint:
2385 /// - an obviously-unsized type
2386 /// - a type parameter or projection whose Sizedness can't be known
2387 /// - a tuple of type parameters or projections, if there are multiple
2389 /// - a TyError, if a type contained itself. The representability
2390 /// check should catch this case.
2391 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2393 -> &'tcx [Ty<'tcx>] {
2394 let def = tcx.adt_def(def_id);
2396 let result = tcx.intern_type_list(&def.variants.iter().flat_map(|v| {
2399 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2400 }).collect::<Vec<_>>());
2402 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2407 /// Calculates the dtorck constraint for a type.
2408 fn adt_dtorck_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2410 -> DtorckConstraint<'tcx> {
2411 let def = tcx.adt_def(def_id);
2412 let span = tcx.def_span(def_id);
2413 debug!("dtorck_constraint: {:?}", def);
2415 if def.is_phantom_data() {
2416 let result = DtorckConstraint {
2419 tcx.mk_param_from_def(&tcx.generics_of(def_id).types[0])
2422 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2426 let mut result = def.all_fields()
2427 .map(|field| tcx.type_of(field.did))
2428 .map(|fty| tcx.dtorck_constraint_for_ty(span, fty, 0, fty))
2429 .collect::<Result<DtorckConstraint, ErrorReported>>()
2430 .unwrap_or(DtorckConstraint::empty());
2431 result.outlives.extend(tcx.destructor_constraints(def));
2434 debug!("dtorck_constraint: {:?} => {:?}", def, result);
2439 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2442 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2443 let item = tcx.hir.expect_item(id);
2444 let vec: Vec<_> = match item.node {
2445 hir::ItemTrait(.., ref trait_item_refs) => {
2446 trait_item_refs.iter()
2447 .map(|trait_item_ref| trait_item_ref.id)
2448 .map(|id| tcx.hir.local_def_id(id.node_id))
2451 hir::ItemImpl(.., ref impl_item_refs) => {
2452 impl_item_refs.iter()
2453 .map(|impl_item_ref| impl_item_ref.id)
2454 .map(|id| tcx.hir.local_def_id(id.node_id))
2457 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2462 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
2463 tcx.hir.span_if_local(def_id).unwrap()
2466 /// If the given def ID describes an item belonging to a trait,
2467 /// return the ID of the trait that the trait item belongs to.
2468 /// Otherwise, return `None`.
2469 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
2470 tcx.opt_associated_item(def_id)
2471 .and_then(|associated_item| {
2472 match associated_item.container {
2473 TraitContainer(def_id) => Some(def_id),
2474 ImplContainer(_) => None
2479 /// See `ParamEnv` struct def'n for details.
2480 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2483 // Compute the bounds on Self and the type parameters.
2485 let bounds = tcx.predicates_of(def_id).instantiate_identity(tcx);
2486 let predicates = bounds.predicates;
2488 // Finally, we have to normalize the bounds in the environment, in
2489 // case they contain any associated type projections. This process
2490 // can yield errors if the put in illegal associated types, like
2491 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2492 // report these errors right here; this doesn't actually feel
2493 // right to me, because constructing the environment feels like a
2494 // kind of a "idempotent" action, but I'm not sure where would be
2495 // a better place. In practice, we construct environments for
2496 // every fn once during type checking, and we'll abort if there
2497 // are any errors at that point, so after type checking you can be
2498 // sure that this will succeed without errors anyway.
2500 let unnormalized_env = ty::ParamEnv::new(tcx.intern_predicates(&predicates),
2501 traits::Reveal::UserFacing);
2503 let body_id = tcx.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
2504 tcx.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_id)
2506 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
2507 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
2510 pub fn provide(providers: &mut ty::maps::Providers) {
2511 util::provide(providers);
2512 *providers = ty::maps::Providers {
2514 associated_item_def_ids,
2515 adt_sized_constraint,
2516 adt_dtorck_constraint,
2520 trait_impls_of: trait_def::trait_impls_of_provider,
2525 pub fn provide_extern(providers: &mut ty::maps::Providers) {
2526 *providers = ty::maps::Providers {
2527 adt_sized_constraint,
2528 adt_dtorck_constraint,
2529 trait_impls_of: trait_def::trait_impls_of_provider,
2536 /// A map for the local crate mapping each type to a vector of its
2537 /// inherent impls. This is not meant to be used outside of coherence;
2538 /// rather, you should request the vector for a specific type via
2539 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2540 /// (constructing this map requires touching the entire crate).
2541 #[derive(Clone, Debug)]
2542 pub struct CrateInherentImpls {
2543 pub inherent_impls: DefIdMap<Rc<Vec<DefId>>>,
2546 /// A set of constraints that need to be satisfied in order for
2547 /// a type to be valid for destruction.
2548 #[derive(Clone, Debug)]
2549 pub struct DtorckConstraint<'tcx> {
2550 /// Types that are required to be alive in order for this
2551 /// type to be valid for destruction.
2552 pub outlives: Vec<ty::subst::Kind<'tcx>>,
2553 /// Types that could not be resolved: projections and params.
2554 pub dtorck_types: Vec<Ty<'tcx>>,
2557 impl<'tcx> FromIterator<DtorckConstraint<'tcx>> for DtorckConstraint<'tcx>
2559 fn from_iter<I: IntoIterator<Item=DtorckConstraint<'tcx>>>(iter: I) -> Self {
2560 let mut result = Self::empty();
2562 for constraint in iter {
2563 result.outlives.extend(constraint.outlives);
2564 result.dtorck_types.extend(constraint.dtorck_types);
2572 impl<'tcx> DtorckConstraint<'tcx> {
2573 fn empty() -> DtorckConstraint<'tcx> {
2576 dtorck_types: vec![]
2580 fn dedup<'a>(&mut self) {
2581 let mut outlives = FxHashSet();
2582 let mut dtorck_types = FxHashSet();
2584 self.outlives.retain(|&val| outlives.replace(val).is_none());
2585 self.dtorck_types.retain(|&val| dtorck_types.replace(val).is_none());
2589 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord)]
2590 pub struct SymbolName {
2591 // FIXME: we don't rely on interning or equality here - better have
2592 // this be a `&'tcx str`.
2593 pub name: InternedString
2596 impl Deref for SymbolName {
2599 fn deref(&self) -> &str { &self.name }
2602 impl fmt::Display for SymbolName {
2603 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2604 fmt::Display::fmt(&self.name, fmt)