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::fold::TypeFoldable;
17 use hir::{map as hir_map, FreevarMap, TraitMap};
19 use hir::def::{Def, CtorKind, ExportMap};
20 use hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
21 use hir::map::DefPathData;
22 use rustc_data_structures::svh::Svh;
24 use ich::StableHashingContext;
25 use infer::canonical::Canonical;
26 use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
27 use middle::privacy::AccessLevels;
28 use middle::resolve_lifetime::ObjectLifetimeDefault;
30 use mir::interpret::GlobalId;
31 use mir::GeneratorLayout;
32 use session::CrateDisambiguator;
33 use traits::{self, Reveal};
35 use ty::subst::{Subst, Substs};
36 use ty::util::{IntTypeExt, Discr};
37 use ty::walk::TypeWalker;
38 use util::captures::Captures;
39 use util::nodemap::{NodeSet, DefIdMap, FxHashMap};
40 use arena::SyncDroplessArena;
41 use session::DataTypeKind;
43 use serialize::{self, Encodable, Encoder};
44 use std::cell::RefCell;
45 use std::cmp::{self, Ordering};
47 use std::hash::{Hash, Hasher};
49 use rustc_data_structures::sync::{self, Lrc, ParallelIterator, par_iter};
51 use std::vec::IntoIter;
53 use syntax::ast::{self, DUMMY_NODE_ID, Name, Ident, NodeId};
55 use syntax::ext::hygiene::Mark;
56 use syntax::symbol::{keywords, Symbol, LocalInternedString, InternedString};
57 use syntax_pos::{DUMMY_SP, Span};
60 use rustc_data_structures::indexed_vec::Idx;
61 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
66 pub use self::sty::{Binder, CanonicalVar, DebruijnIndex, INNERMOST};
67 pub use self::sty::{FnSig, GenSig, PolyFnSig, PolyGenSig};
68 pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
69 pub use self::sty::{ClosureSubsts, GeneratorSubsts, UpvarSubsts, TypeAndMut};
70 pub use self::sty::{TraitRef, TyKind, PolyTraitRef};
71 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
72 pub use self::sty::{ExistentialProjection, PolyExistentialProjection, Const};
73 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
74 pub use self::sty::RegionKind;
75 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid};
76 pub use self::sty::BoundRegion::*;
77 pub use self::sty::InferTy::*;
78 pub use self::sty::RegionKind::*;
79 pub use self::sty::TyKind::*;
81 pub use self::binding::BindingMode;
82 pub use self::binding::BindingMode::*;
84 pub use self::context::{TyCtxt, FreeRegionInfo, GlobalArenas, AllArenas, tls, keep_local};
85 pub use self::context::{Lift, TypeckTables};
87 pub use self::instance::{Instance, InstanceDef};
89 pub use self::trait_def::TraitDef;
91 pub use self::query::queries;
103 pub mod inhabitedness;
120 mod structural_impls;
125 /// The complete set of all analyses described in this module. This is
126 /// produced by the driver and fed to codegen and later passes.
128 /// NB: These contents are being migrated into queries using the
129 /// *on-demand* infrastructure.
131 pub struct CrateAnalysis {
132 pub access_levels: Lrc<AccessLevels>,
134 pub glob_map: Option<hir::GlobMap>,
138 pub struct Resolutions {
139 pub freevars: FreevarMap,
140 pub trait_map: TraitMap,
141 pub maybe_unused_trait_imports: NodeSet,
142 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
143 pub export_map: ExportMap,
146 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
147 pub enum AssociatedItemContainer {
148 TraitContainer(DefId),
149 ImplContainer(DefId),
152 impl AssociatedItemContainer {
153 /// Asserts that this is the def-id of an associated item declared
154 /// in a trait, and returns the trait def-id.
155 pub fn assert_trait(&self) -> DefId {
157 TraitContainer(id) => id,
158 _ => bug!("associated item has wrong container type: {:?}", self)
162 pub fn id(&self) -> DefId {
164 TraitContainer(id) => id,
165 ImplContainer(id) => id,
170 /// The "header" of an impl is everything outside the body: a Self type, a trait
171 /// ref (in the case of a trait impl), and a set of predicates (from the
172 /// bounds/where clauses).
173 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
174 pub struct ImplHeader<'tcx> {
175 pub impl_def_id: DefId,
176 pub self_ty: Ty<'tcx>,
177 pub trait_ref: Option<TraitRef<'tcx>>,
178 pub predicates: Vec<Predicate<'tcx>>,
181 #[derive(Copy, Clone, Debug, PartialEq)]
182 pub struct AssociatedItem {
185 pub kind: AssociatedKind,
187 pub defaultness: hir::Defaultness,
188 pub container: AssociatedItemContainer,
190 /// Whether this is a method with an explicit self
191 /// as its first argument, allowing method calls.
192 pub method_has_self_argument: bool,
195 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash, RustcEncodable, RustcDecodable)]
196 pub enum AssociatedKind {
203 impl AssociatedItem {
204 pub fn def(&self) -> Def {
206 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
207 AssociatedKind::Method => Def::Method(self.def_id),
208 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
209 AssociatedKind::Existential => Def::AssociatedExistential(self.def_id),
213 /// Tests whether the associated item admits a non-trivial implementation
215 pub fn relevant_for_never<'tcx>(&self) -> bool {
217 AssociatedKind::Existential |
218 AssociatedKind::Const |
219 AssociatedKind::Type => true,
220 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
221 AssociatedKind::Method => !self.method_has_self_argument,
225 pub fn signature<'a, 'tcx>(&self, tcx: &TyCtxt<'a, 'tcx, 'tcx>) -> String {
227 ty::AssociatedKind::Method => {
228 // We skip the binder here because the binder would deanonymize all
229 // late-bound regions, and we don't want method signatures to show up
230 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
231 // regions just fine, showing `fn(&MyType)`.
232 tcx.fn_sig(self.def_id).skip_binder().to_string()
234 ty::AssociatedKind::Type => format!("type {};", self.ident),
235 ty::AssociatedKind::Existential => format!("existential type {};", self.ident),
236 ty::AssociatedKind::Const => {
237 format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id))
243 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
244 pub enum Visibility {
245 /// Visible everywhere (including in other crates).
247 /// Visible only in the given crate-local module.
249 /// Not visible anywhere in the local crate. This is the visibility of private external items.
253 pub trait DefIdTree: Copy {
254 fn parent(self, id: DefId) -> Option<DefId>;
256 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
257 if descendant.krate != ancestor.krate {
261 while descendant != ancestor {
262 match self.parent(descendant) {
263 Some(parent) => descendant = parent,
264 None => return false,
271 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
272 fn parent(self, id: DefId) -> Option<DefId> {
273 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
278 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt<'_, '_, '_>) -> Self {
279 match visibility.node {
280 hir::VisibilityKind::Public => Visibility::Public,
281 hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
282 hir::VisibilityKind::Restricted { ref path, .. } => match path.def {
283 // If there is no resolution, `resolve` will have already reported an error, so
284 // assume that the visibility is public to avoid reporting more privacy errors.
285 Def::Err => Visibility::Public,
286 def => Visibility::Restricted(def.def_id()),
288 hir::VisibilityKind::Inherited => {
289 Visibility::Restricted(tcx.hir.get_module_parent(id))
294 /// Returns true if an item with this visibility is accessible from the given block.
295 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
296 let restriction = match self {
297 // Public items are visible everywhere.
298 Visibility::Public => return true,
299 // Private items from other crates are visible nowhere.
300 Visibility::Invisible => return false,
301 // Restricted items are visible in an arbitrary local module.
302 Visibility::Restricted(other) if other.krate != module.krate => return false,
303 Visibility::Restricted(module) => module,
306 tree.is_descendant_of(module, restriction)
309 /// Returns true if this visibility is at least as accessible as the given visibility
310 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
311 let vis_restriction = match vis {
312 Visibility::Public => return self == Visibility::Public,
313 Visibility::Invisible => return true,
314 Visibility::Restricted(module) => module,
317 self.is_accessible_from(vis_restriction, tree)
320 // Returns true if this item is visible anywhere in the local crate.
321 pub fn is_visible_locally(self) -> bool {
323 Visibility::Public => true,
324 Visibility::Restricted(def_id) => def_id.is_local(),
325 Visibility::Invisible => false,
330 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
332 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
333 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
334 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
335 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
338 /// The crate variances map is computed during typeck and contains the
339 /// variance of every item in the local crate. You should not use it
340 /// directly, because to do so will make your pass dependent on the
341 /// HIR of every item in the local crate. Instead, use
342 /// `tcx.variances_of()` to get the variance for a *particular*
344 pub struct CrateVariancesMap {
345 /// For each item with generics, maps to a vector of the variance
346 /// of its generics. If an item has no generics, it will have no
348 pub variances: FxHashMap<DefId, Lrc<Vec<ty::Variance>>>,
350 /// An empty vector, useful for cloning.
351 pub empty_variance: Lrc<Vec<ty::Variance>>,
355 /// `a.xform(b)` combines the variance of a context with the
356 /// variance of a type with the following meaning. If we are in a
357 /// context with variance `a`, and we encounter a type argument in
358 /// a position with variance `b`, then `a.xform(b)` is the new
359 /// variance with which the argument appears.
365 /// Here, the "ambient" variance starts as covariant. `*mut T` is
366 /// invariant with respect to `T`, so the variance in which the
367 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
368 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
369 /// respect to its type argument `T`, and hence the variance of
370 /// the `i32` here is `Invariant.xform(Covariant)`, which results
371 /// (again) in `Invariant`.
375 /// fn(*const Vec<i32>, *mut Vec<i32)
377 /// The ambient variance is covariant. A `fn` type is
378 /// contravariant with respect to its parameters, so the variance
379 /// within which both pointer types appear is
380 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
381 /// T` is covariant with respect to `T`, so the variance within
382 /// which the first `Vec<i32>` appears is
383 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
384 /// is true for its `i32` argument. In the `*mut T` case, the
385 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
386 /// and hence the outermost type is `Invariant` with respect to
387 /// `Vec<i32>` (and its `i32` argument).
389 /// Source: Figure 1 of "Taming the Wildcards:
390 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
391 pub fn xform(self, v: ty::Variance) -> ty::Variance {
393 // Figure 1, column 1.
394 (ty::Covariant, ty::Covariant) => ty::Covariant,
395 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
396 (ty::Covariant, ty::Invariant) => ty::Invariant,
397 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
399 // Figure 1, column 2.
400 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
401 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
402 (ty::Contravariant, ty::Invariant) => ty::Invariant,
403 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
405 // Figure 1, column 3.
406 (ty::Invariant, _) => ty::Invariant,
408 // Figure 1, column 4.
409 (ty::Bivariant, _) => ty::Bivariant,
414 // Contains information needed to resolve types and (in the future) look up
415 // the types of AST nodes.
416 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
417 pub struct CReaderCacheKey {
422 // Flags that we track on types. These flags are propagated upwards
423 // through the type during type construction, so that we can quickly
424 // check whether the type has various kinds of types in it without
425 // recursing over the type itself.
427 pub struct TypeFlags: u32 {
428 const HAS_PARAMS = 1 << 0;
429 const HAS_SELF = 1 << 1;
430 const HAS_TY_INFER = 1 << 2;
431 const HAS_RE_INFER = 1 << 3;
432 const HAS_RE_SKOL = 1 << 4;
434 /// Does this have any `ReEarlyBound` regions? Used to
435 /// determine whether substitition is required, since those
436 /// represent regions that are bound in a `ty::Generics` and
437 /// hence may be substituted.
438 const HAS_RE_EARLY_BOUND = 1 << 5;
440 /// Does this have any region that "appears free" in the type?
441 /// Basically anything but `ReLateBound` and `ReErased`.
442 const HAS_FREE_REGIONS = 1 << 6;
444 /// Is an error type reachable?
445 const HAS_TY_ERR = 1 << 7;
446 const HAS_PROJECTION = 1 << 8;
448 // FIXME: Rename this to the actual property since it's used for generators too
449 const HAS_TY_CLOSURE = 1 << 9;
451 // true if there are "names" of types and regions and so forth
452 // that are local to a particular fn
453 const HAS_FREE_LOCAL_NAMES = 1 << 10;
455 // Present if the type belongs in a local type context.
456 // Only set for Infer other than Fresh.
457 const KEEP_IN_LOCAL_TCX = 1 << 11;
459 // Is there a projection that does not involve a bound region?
460 // Currently we can't normalize projections w/ bound regions.
461 const HAS_NORMALIZABLE_PROJECTION = 1 << 12;
463 // Set if this includes a "canonical" type or region var --
464 // ought to be true only for the results of canonicalization.
465 const HAS_CANONICAL_VARS = 1 << 13;
467 /// Does this have any `ReLateBound` regions? Used to check
468 /// if a global bound is safe to evaluate.
469 const HAS_RE_LATE_BOUND = 1 << 14;
471 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
472 TypeFlags::HAS_SELF.bits |
473 TypeFlags::HAS_RE_EARLY_BOUND.bits;
475 // Flags representing the nominal content of a type,
476 // computed by FlagsComputation. If you add a new nominal
477 // flag, it should be added here too.
478 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
479 TypeFlags::HAS_SELF.bits |
480 TypeFlags::HAS_TY_INFER.bits |
481 TypeFlags::HAS_RE_INFER.bits |
482 TypeFlags::HAS_RE_SKOL.bits |
483 TypeFlags::HAS_RE_EARLY_BOUND.bits |
484 TypeFlags::HAS_FREE_REGIONS.bits |
485 TypeFlags::HAS_TY_ERR.bits |
486 TypeFlags::HAS_PROJECTION.bits |
487 TypeFlags::HAS_TY_CLOSURE.bits |
488 TypeFlags::HAS_FREE_LOCAL_NAMES.bits |
489 TypeFlags::KEEP_IN_LOCAL_TCX.bits |
490 TypeFlags::HAS_CANONICAL_VARS.bits |
491 TypeFlags::HAS_RE_LATE_BOUND.bits;
495 pub struct TyS<'tcx> {
496 pub sty: TyKind<'tcx>,
497 pub flags: TypeFlags,
499 /// This is a kind of confusing thing: it stores the smallest
502 /// (a) the binder itself captures nothing but
503 /// (b) all the late-bound things within the type are captured
504 /// by some sub-binder.
506 /// So, for a type without any late-bound things, like `u32`, this
507 /// will be INNERMOST, because that is the innermost binder that
508 /// captures nothing. But for a type `&'D u32`, where `'D` is a
509 /// late-bound region with debruijn index D, this would be D+1 --
510 /// the binder itself does not capture D, but D is captured by an
513 /// We call this concept an "exclusive" binder D (because all
514 /// debruijn indices within the type are contained within `0..D`
516 outer_exclusive_binder: ty::DebruijnIndex,
519 impl<'tcx> Ord for TyS<'tcx> {
520 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
521 self.sty.cmp(&other.sty)
525 impl<'tcx> PartialOrd for TyS<'tcx> {
526 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
527 Some(self.sty.cmp(&other.sty))
531 impl<'tcx> PartialEq for TyS<'tcx> {
533 fn eq(&self, other: &TyS<'tcx>) -> bool {
537 impl<'tcx> Eq for TyS<'tcx> {}
539 impl<'tcx> Hash for TyS<'tcx> {
540 fn hash<H: Hasher>(&self, s: &mut H) {
541 (self as *const TyS<'_>).hash(s)
545 impl<'tcx> TyS<'tcx> {
546 pub fn is_primitive_ty(&self) -> bool {
553 TyKind::Infer(InferTy::IntVar(_)) |
554 TyKind::Infer(InferTy::FloatVar(_)) |
555 TyKind::Infer(InferTy::FreshIntTy(_)) |
556 TyKind::Infer(InferTy::FreshFloatTy(_)) => true,
557 TyKind::Ref(_, x, _) => x.is_primitive_ty(),
562 pub fn is_suggestable(&self) -> bool {
567 TyKind::Dynamic(..) |
568 TyKind::Closure(..) |
570 TyKind::Projection(..) => false,
576 impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for ty::TyS<'gcx> {
577 fn hash_stable<W: StableHasherResult>(&self,
578 hcx: &mut StableHashingContext<'a>,
579 hasher: &mut StableHasher<W>) {
583 // The other fields just provide fast access to information that is
584 // also contained in `sty`, so no need to hash them.
587 outer_exclusive_binder: _,
590 sty.hash_stable(hcx, hasher);
594 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
596 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
597 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
599 pub type CanonicalTy<'gcx> = Canonical<'gcx, Ty<'gcx>>;
602 /// A dummy type used to force List to by unsized without requiring fat pointers
603 type OpaqueListContents;
606 /// A wrapper for slices with the additional invariant
607 /// that the slice is interned and no other slice with
608 /// the same contents can exist in the same context.
609 /// This means we can use pointer for both
610 /// equality comparisons and hashing.
611 /// Note: `Slice` was already taken by the `Ty`.
616 opaque: OpaqueListContents,
619 unsafe impl<T: Sync> Sync for List<T> {}
621 impl<T: Copy> List<T> {
623 fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx List<T> {
624 assert!(!mem::needs_drop::<T>());
625 assert!(mem::size_of::<T>() != 0);
626 assert!(slice.len() != 0);
628 // Align up the size of the len (usize) field
629 let align = mem::align_of::<T>();
630 let align_mask = align - 1;
631 let offset = mem::size_of::<usize>();
632 let offset = (offset + align_mask) & !align_mask;
634 let size = offset + slice.len() * mem::size_of::<T>();
636 let mem = arena.alloc_raw(
638 cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
640 let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
642 result.len = slice.len();
644 // Write the elements
645 let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
646 arena_slice.copy_from_slice(slice);
653 impl<T: fmt::Debug> fmt::Debug for List<T> {
654 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
659 impl<T: Encodable> Encodable for List<T> {
661 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
666 impl<T> Ord for List<T> where T: Ord {
667 fn cmp(&self, other: &List<T>) -> Ordering {
668 if self == other { Ordering::Equal } else {
669 <[T] as Ord>::cmp(&**self, &**other)
674 impl<T> PartialOrd for List<T> where T: PartialOrd {
675 fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> {
676 if self == other { Some(Ordering::Equal) } else {
677 <[T] as PartialOrd>::partial_cmp(&**self, &**other)
682 impl<T: PartialEq> PartialEq for List<T> {
684 fn eq(&self, other: &List<T>) -> bool {
688 impl<T: Eq> Eq for List<T> {}
690 impl<T> Hash for List<T> {
692 fn hash<H: Hasher>(&self, s: &mut H) {
693 (self as *const List<T>).hash(s)
697 impl<T> Deref for List<T> {
700 fn deref(&self) -> &[T] {
702 slice::from_raw_parts(self.data.as_ptr(), self.len)
707 impl<'a, T> IntoIterator for &'a List<T> {
709 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
711 fn into_iter(self) -> Self::IntoIter {
716 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
720 pub fn empty<'a>() -> &'a List<T> {
721 #[repr(align(64), C)]
722 struct EmptySlice([u8; 64]);
723 static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
724 assert!(mem::align_of::<T>() <= 64);
726 &*(&EMPTY_SLICE as *const _ as *const List<T>)
731 /// Upvars do not get their own node-id. Instead, we use the pair of
732 /// the original var id (that is, the root variable that is referenced
733 /// by the upvar) and the id of the closure expression.
734 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
736 pub var_id: hir::HirId,
737 pub closure_expr_id: LocalDefId,
740 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
741 pub enum BorrowKind {
742 /// Data must be immutable and is aliasable.
745 /// Data must be immutable but not aliasable. This kind of borrow
746 /// cannot currently be expressed by the user and is used only in
747 /// implicit closure bindings. It is needed when the closure
748 /// is borrowing or mutating a mutable referent, e.g.:
750 /// let x: &mut isize = ...;
751 /// let y = || *x += 5;
753 /// If we were to try to translate this closure into a more explicit
754 /// form, we'd encounter an error with the code as written:
756 /// struct Env { x: & &mut isize }
757 /// let x: &mut isize = ...;
758 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
759 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
761 /// This is then illegal because you cannot mutate a `&mut` found
762 /// in an aliasable location. To solve, you'd have to translate with
763 /// an `&mut` borrow:
765 /// struct Env { x: & &mut isize }
766 /// let x: &mut isize = ...;
767 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
768 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
770 /// Now the assignment to `**env.x` is legal, but creating a
771 /// mutable pointer to `x` is not because `x` is not mutable. We
772 /// could fix this by declaring `x` as `let mut x`. This is ok in
773 /// user code, if awkward, but extra weird for closures, since the
774 /// borrow is hidden.
776 /// So we introduce a "unique imm" borrow -- the referent is
777 /// immutable, but not aliasable. This solves the problem. For
778 /// simplicity, we don't give users the way to express this
779 /// borrow, it's just used when translating closures.
782 /// Data is mutable and not aliasable.
786 /// Information describing the capture of an upvar. This is computed
787 /// during `typeck`, specifically by `regionck`.
788 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
789 pub enum UpvarCapture<'tcx> {
790 /// Upvar is captured by value. This is always true when the
791 /// closure is labeled `move`, but can also be true in other cases
792 /// depending on inference.
795 /// Upvar is captured by reference.
796 ByRef(UpvarBorrow<'tcx>),
799 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
800 pub struct UpvarBorrow<'tcx> {
801 /// The kind of borrow: by-ref upvars have access to shared
802 /// immutable borrows, which are not part of the normal language
804 pub kind: BorrowKind,
806 /// Region of the resulting reference.
807 pub region: ty::Region<'tcx>,
810 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
812 #[derive(Copy, Clone)]
813 pub struct ClosureUpvar<'tcx> {
819 #[derive(Clone, Copy, PartialEq, Eq)]
820 pub enum IntVarValue {
822 UintType(ast::UintTy),
825 #[derive(Clone, Copy, PartialEq, Eq)]
826 pub struct FloatVarValue(pub ast::FloatTy);
828 impl ty::EarlyBoundRegion {
829 pub fn to_bound_region(&self) -> ty::BoundRegion {
830 ty::BoundRegion::BrNamed(self.def_id, self.name)
833 /// Does this early bound region have a name? Early bound regions normally
834 /// always have names except when using anonymous lifetimes (`'_`).
835 pub fn has_name(&self) -> bool {
836 self.name != keywords::UnderscoreLifetime.name().as_interned_str()
840 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
841 pub enum GenericParamDefKind {
845 object_lifetime_default: ObjectLifetimeDefault,
846 synthetic: Option<hir::SyntheticTyParamKind>,
850 #[derive(Clone, RustcEncodable, RustcDecodable)]
851 pub struct GenericParamDef {
852 pub name: InternedString,
856 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
857 /// on generic parameter `'a`/`T`, asserts data behind the parameter
858 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
859 pub pure_wrt_drop: bool,
861 pub kind: GenericParamDefKind,
864 impl GenericParamDef {
865 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
866 if let GenericParamDefKind::Lifetime = self.kind {
867 ty::EarlyBoundRegion {
873 bug!("cannot convert a non-lifetime parameter def to an early bound region")
877 pub fn to_bound_region(&self) -> ty::BoundRegion {
878 if let GenericParamDefKind::Lifetime = self.kind {
879 self.to_early_bound_region_data().to_bound_region()
881 bug!("cannot convert a non-lifetime parameter def to an early bound region")
887 pub struct GenericParamCount {
888 pub lifetimes: usize,
892 /// Information about the formal type/lifetime parameters associated
893 /// with an item or method. Analogous to hir::Generics.
895 /// The ordering of parameters is the same as in Subst (excluding child generics):
896 /// Self (optionally), Lifetime params..., Type params...
897 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
898 pub struct Generics {
899 pub parent: Option<DefId>,
900 pub parent_count: usize,
901 pub params: Vec<GenericParamDef>,
903 /// Reverse map to the `index` field of each `GenericParamDef`
904 pub param_def_id_to_index: FxHashMap<DefId, u32>,
907 pub has_late_bound_regions: Option<Span>,
910 impl<'a, 'gcx, 'tcx> Generics {
911 pub fn count(&self) -> usize {
912 self.parent_count + self.params.len()
915 pub fn own_counts(&self) -> GenericParamCount {
916 // We could cache this as a property of `GenericParamCount`, but
917 // the aim is to refactor this away entirely eventually and the
918 // presence of this method will be a constant reminder.
919 let mut own_counts: GenericParamCount = Default::default();
921 for param in &self.params {
923 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
924 GenericParamDefKind::Type { .. } => own_counts.types += 1,
931 pub fn requires_monomorphization(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
932 for param in &self.params {
934 GenericParamDefKind::Type { .. } => return true,
935 GenericParamDefKind::Lifetime => {}
938 if let Some(parent_def_id) = self.parent {
939 let parent = tcx.generics_of(parent_def_id);
940 parent.requires_monomorphization(tcx)
946 pub fn region_param(&'tcx self,
947 param: &EarlyBoundRegion,
948 tcx: TyCtxt<'a, 'gcx, 'tcx>)
949 -> &'tcx GenericParamDef
951 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
952 let param = &self.params[index as usize];
954 ty::GenericParamDefKind::Lifetime => param,
955 _ => bug!("expected lifetime parameter, but found another generic parameter")
958 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
959 .region_param(param, tcx)
963 /// Returns the `GenericParamDef` associated with this `ParamTy`.
964 pub fn type_param(&'tcx self,
966 tcx: TyCtxt<'a, 'gcx, 'tcx>)
967 -> &'tcx GenericParamDef {
968 if let Some(index) = param.idx.checked_sub(self.parent_count as u32) {
969 let param = &self.params[index as usize];
971 ty::GenericParamDefKind::Type {..} => param,
972 _ => bug!("expected type parameter, but found another generic parameter")
975 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
976 .type_param(param, tcx)
981 /// Bounds on generics.
982 #[derive(Clone, Default)]
983 pub struct GenericPredicates<'tcx> {
984 pub parent: Option<DefId>,
985 pub predicates: Vec<(Predicate<'tcx>, Span)>,
988 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
989 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
991 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
992 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
993 -> InstantiatedPredicates<'tcx> {
994 let mut instantiated = InstantiatedPredicates::empty();
995 self.instantiate_into(tcx, &mut instantiated, substs);
998 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
999 -> InstantiatedPredicates<'tcx> {
1000 InstantiatedPredicates {
1001 predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
1005 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1006 instantiated: &mut InstantiatedPredicates<'tcx>,
1007 substs: &Substs<'tcx>) {
1008 if let Some(def_id) = self.parent {
1009 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
1011 instantiated.predicates.extend(
1012 self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)),
1016 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1017 -> InstantiatedPredicates<'tcx> {
1018 let mut instantiated = InstantiatedPredicates::empty();
1019 self.instantiate_identity_into(tcx, &mut instantiated);
1023 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1024 instantiated: &mut InstantiatedPredicates<'tcx>) {
1025 if let Some(def_id) = self.parent {
1026 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
1028 instantiated.predicates.extend(self.predicates.iter().map(|&(p, _)| p))
1031 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1032 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
1033 -> InstantiatedPredicates<'tcx>
1035 assert_eq!(self.parent, None);
1036 InstantiatedPredicates {
1037 predicates: self.predicates.iter().map(|(pred, _)| {
1038 pred.subst_supertrait(tcx, poly_trait_ref)
1044 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1045 pub enum Predicate<'tcx> {
1046 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
1047 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1048 /// would be the type parameters.
1049 Trait(PolyTraitPredicate<'tcx>),
1052 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1055 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1057 /// where <T as TraitRef>::Name == X, approximately.
1058 /// See `ProjectionPredicate` struct for details.
1059 Projection(PolyProjectionPredicate<'tcx>),
1062 WellFormed(Ty<'tcx>),
1064 /// trait must be object-safe
1067 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
1068 /// for some substitutions `...` and T being a closure type.
1069 /// Satisfied (or refuted) once we know the closure's kind.
1070 ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
1073 Subtype(PolySubtypePredicate<'tcx>),
1075 /// Constant initializer must evaluate successfully.
1076 ConstEvaluatable(DefId, &'tcx Substs<'tcx>),
1079 /// The crate outlives map is computed during typeck and contains the
1080 /// outlives of every item in the local crate. You should not use it
1081 /// directly, because to do so will make your pass dependent on the
1082 /// HIR of every item in the local crate. Instead, use
1083 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1085 pub struct CratePredicatesMap<'tcx> {
1086 /// For each struct with outlive bounds, maps to a vector of the
1087 /// predicate of its outlive bounds. If an item has no outlives
1088 /// bounds, it will have no entry.
1089 pub predicates: FxHashMap<DefId, Lrc<Vec<ty::Predicate<'tcx>>>>,
1091 /// An empty vector, useful for cloning.
1092 pub empty_predicate: Lrc<Vec<ty::Predicate<'tcx>>>,
1095 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1096 fn as_ref(&self) -> &Predicate<'tcx> {
1101 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
1102 /// Performs a substitution suitable for going from a
1103 /// poly-trait-ref to supertraits that must hold if that
1104 /// poly-trait-ref holds. This is slightly different from a normal
1105 /// substitution in terms of what happens with bound regions. See
1106 /// lengthy comment below for details.
1107 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1108 trait_ref: &ty::PolyTraitRef<'tcx>)
1109 -> ty::Predicate<'tcx>
1111 // The interaction between HRTB and supertraits is not entirely
1112 // obvious. Let me walk you (and myself) through an example.
1114 // Let's start with an easy case. Consider two traits:
1116 // trait Foo<'a> : Bar<'a,'a> { }
1117 // trait Bar<'b,'c> { }
1119 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
1120 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
1121 // knew that `Foo<'x>` (for any 'x) then we also know that
1122 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1123 // normal substitution.
1125 // In terms of why this is sound, the idea is that whenever there
1126 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1127 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1128 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1131 // Another example to be careful of is this:
1133 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
1134 // trait Bar1<'b,'c> { }
1136 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
1137 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
1138 // reason is similar to the previous example: any impl of
1139 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
1140 // basically we would want to collapse the bound lifetimes from
1141 // the input (`trait_ref`) and the supertraits.
1143 // To achieve this in practice is fairly straightforward. Let's
1144 // consider the more complicated scenario:
1146 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
1147 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
1148 // where both `'x` and `'b` would have a DB index of 1.
1149 // The substitution from the input trait-ref is therefore going to be
1150 // `'a => 'x` (where `'x` has a DB index of 1).
1151 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1152 // early-bound parameter and `'b' is a late-bound parameter with a
1154 // - If we replace `'a` with `'x` from the input, it too will have
1155 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1156 // just as we wanted.
1158 // There is only one catch. If we just apply the substitution `'a
1159 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1160 // adjust the DB index because we substituting into a binder (it
1161 // tries to be so smart...) resulting in `for<'x> for<'b>
1162 // Bar1<'x,'b>` (we have no syntax for this, so use your
1163 // imagination). Basically the 'x will have DB index of 2 and 'b
1164 // will have DB index of 1. Not quite what we want. So we apply
1165 // the substitution to the *contents* of the trait reference,
1166 // rather than the trait reference itself (put another way, the
1167 // substitution code expects equal binding levels in the values
1168 // from the substitution and the value being substituted into, and
1169 // this trick achieves that).
1171 let substs = &trait_ref.skip_binder().substs;
1173 Predicate::Trait(ref binder) =>
1174 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1175 Predicate::Subtype(ref binder) =>
1176 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1177 Predicate::RegionOutlives(ref binder) =>
1178 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1179 Predicate::TypeOutlives(ref binder) =>
1180 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1181 Predicate::Projection(ref binder) =>
1182 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1183 Predicate::WellFormed(data) =>
1184 Predicate::WellFormed(data.subst(tcx, substs)),
1185 Predicate::ObjectSafe(trait_def_id) =>
1186 Predicate::ObjectSafe(trait_def_id),
1187 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1188 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1189 Predicate::ConstEvaluatable(def_id, const_substs) =>
1190 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1195 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1196 pub struct TraitPredicate<'tcx> {
1197 pub trait_ref: TraitRef<'tcx>
1199 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1201 impl<'tcx> TraitPredicate<'tcx> {
1202 pub fn def_id(&self) -> DefId {
1203 self.trait_ref.def_id
1206 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
1207 self.trait_ref.input_types()
1210 pub fn self_ty(&self) -> Ty<'tcx> {
1211 self.trait_ref.self_ty()
1215 impl<'tcx> PolyTraitPredicate<'tcx> {
1216 pub fn def_id(&self) -> DefId {
1217 // ok to skip binder since trait def-id does not care about regions
1218 self.skip_binder().def_id()
1222 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
1223 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
1224 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1225 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>,
1227 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>,
1229 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1230 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1232 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1233 pub struct SubtypePredicate<'tcx> {
1234 pub a_is_expected: bool,
1238 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1240 /// This kind of predicate has no *direct* correspondent in the
1241 /// syntax, but it roughly corresponds to the syntactic forms:
1243 /// 1. `T : TraitRef<..., Item=Type>`
1244 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1246 /// In particular, form #1 is "desugared" to the combination of a
1247 /// normal trait predicate (`T : TraitRef<...>`) and one of these
1248 /// predicates. Form #2 is a broader form in that it also permits
1249 /// equality between arbitrary types. Processing an instance of
1250 /// Form #2 eventually yields one of these `ProjectionPredicate`
1251 /// instances to normalize the LHS.
1252 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1253 pub struct ProjectionPredicate<'tcx> {
1254 pub projection_ty: ProjectionTy<'tcx>,
1258 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1260 impl<'tcx> PolyProjectionPredicate<'tcx> {
1261 /// Returns the def-id of the associated item being projected.
1262 pub fn item_def_id(&self) -> DefId {
1263 self.skip_binder().projection_ty.item_def_id
1266 pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'_, '_, '_>) -> PolyTraitRef<'tcx> {
1267 // Note: unlike with TraitRef::to_poly_trait_ref(),
1268 // self.0.trait_ref is permitted to have escaping regions.
1269 // This is because here `self` has a `Binder` and so does our
1270 // return value, so we are preserving the number of binding
1272 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1275 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1276 self.map_bound(|predicate| predicate.ty)
1279 /// The DefId of the TraitItem for the associated type.
1281 /// Note that this is not the DefId of the TraitRef containing this
1282 /// associated type, which is in tcx.associated_item(projection_def_id()).container.
1283 pub fn projection_def_id(&self) -> DefId {
1284 // ok to skip binder since trait def-id does not care about regions
1285 self.skip_binder().projection_ty.item_def_id
1289 pub trait ToPolyTraitRef<'tcx> {
1290 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1293 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1294 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1295 ty::Binder::dummy(self.clone())
1299 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1300 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1301 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1305 pub trait ToPredicate<'tcx> {
1306 fn to_predicate(&self) -> Predicate<'tcx>;
1309 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1310 fn to_predicate(&self) -> Predicate<'tcx> {
1311 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1312 trait_ref: self.clone()
1317 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1318 fn to_predicate(&self) -> Predicate<'tcx> {
1319 ty::Predicate::Trait(self.to_poly_trait_predicate())
1323 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1324 fn to_predicate(&self) -> Predicate<'tcx> {
1325 Predicate::RegionOutlives(self.clone())
1329 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1330 fn to_predicate(&self) -> Predicate<'tcx> {
1331 Predicate::TypeOutlives(self.clone())
1335 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1336 fn to_predicate(&self) -> Predicate<'tcx> {
1337 Predicate::Projection(self.clone())
1341 impl<'tcx> Predicate<'tcx> {
1342 /// Iterates over the types in this predicate. Note that in all
1343 /// cases this is skipping over a binder, so late-bound regions
1344 /// with depth 0 are bound by the predicate.
1345 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1346 let vec: Vec<_> = match *self {
1347 ty::Predicate::Trait(ref data) => {
1348 data.skip_binder().input_types().collect()
1350 ty::Predicate::Subtype(binder) => {
1351 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1354 ty::Predicate::TypeOutlives(binder) => {
1355 vec![binder.skip_binder().0]
1357 ty::Predicate::RegionOutlives(..) => {
1360 ty::Predicate::Projection(ref data) => {
1361 let inner = data.skip_binder();
1362 inner.projection_ty.substs.types().chain(Some(inner.ty)).collect()
1364 ty::Predicate::WellFormed(data) => {
1367 ty::Predicate::ObjectSafe(_trait_def_id) => {
1370 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1371 closure_substs.substs.types().collect()
1373 ty::Predicate::ConstEvaluatable(_, substs) => {
1374 substs.types().collect()
1378 // FIXME: The only reason to collect into a vector here is that I was
1379 // too lazy to make the full (somewhat complicated) iterator
1380 // type that would be needed here. But I wanted this fn to
1381 // return an iterator conceptually, rather than a `Vec`, so as
1382 // to be closer to `Ty::walk`.
1386 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1388 Predicate::Trait(ref t) => {
1389 Some(t.to_poly_trait_ref())
1391 Predicate::Projection(..) |
1392 Predicate::Subtype(..) |
1393 Predicate::RegionOutlives(..) |
1394 Predicate::WellFormed(..) |
1395 Predicate::ObjectSafe(..) |
1396 Predicate::ClosureKind(..) |
1397 Predicate::TypeOutlives(..) |
1398 Predicate::ConstEvaluatable(..) => {
1404 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1406 Predicate::TypeOutlives(data) => {
1409 Predicate::Trait(..) |
1410 Predicate::Projection(..) |
1411 Predicate::Subtype(..) |
1412 Predicate::RegionOutlives(..) |
1413 Predicate::WellFormed(..) |
1414 Predicate::ObjectSafe(..) |
1415 Predicate::ClosureKind(..) |
1416 Predicate::ConstEvaluatable(..) => {
1423 /// Represents the bounds declared on a particular set of type
1424 /// parameters. Should eventually be generalized into a flag list of
1425 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1426 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1427 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1428 /// the `GenericPredicates` are expressed in terms of the bound type
1429 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1430 /// represented a set of bounds for some particular instantiation,
1431 /// meaning that the generic parameters have been substituted with
1436 /// struct Foo<T,U:Bar<T>> { ... }
1438 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1439 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1440 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1441 /// [usize:Bar<isize>]]`.
1443 pub struct InstantiatedPredicates<'tcx> {
1444 pub predicates: Vec<Predicate<'tcx>>,
1447 impl<'tcx> InstantiatedPredicates<'tcx> {
1448 pub fn empty() -> InstantiatedPredicates<'tcx> {
1449 InstantiatedPredicates { predicates: vec![] }
1452 pub fn is_empty(&self) -> bool {
1453 self.predicates.is_empty()
1457 /// "Universes" are used during type- and trait-checking in the
1458 /// presence of `for<..>` binders to control what sets of names are
1459 /// visible. Universes are arranged into a tree: the root universe
1460 /// contains names that are always visible. Each child then adds a new
1461 /// set of names that are visible, in addition to those of its parent.
1462 /// We say that the child universe "extends" the parent universe with
1465 /// To make this more concrete, consider this program:
1469 /// fn bar<T>(x: T) {
1470 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1474 /// The struct name `Foo` is in the root universe U0. But the type
1475 /// parameter `T`, introduced on `bar`, is in an extended universe U1
1476 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
1477 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
1478 /// region `'a` is in a universe U2 that extends U1, because we can
1479 /// name it inside the fn type but not outside.
1481 /// Universes are used to do type- and trait-checking around these
1482 /// "forall" binders (also called **universal quantification**). The
1483 /// idea is that when, in the body of `bar`, we refer to `T` as a
1484 /// type, we aren't referring to any type in particular, but rather a
1485 /// kind of "fresh" type that is distinct from all other types we have
1486 /// actually declared. This is called a **placeholder** type, and we
1487 /// use universes to talk about this. In other words, a type name in
1488 /// universe 0 always corresponds to some "ground" type that the user
1489 /// declared, but a type name in a non-zero universe is a placeholder
1490 /// type -- an idealized representative of "types in general" that we
1491 /// use for checking generic functions.
1493 pub struct UniverseIndex {
1494 DEBUG_FORMAT = "U{}",
1498 impl_stable_hash_for!(struct UniverseIndex { private });
1500 impl UniverseIndex {
1501 pub const ROOT: UniverseIndex = UniverseIndex::from_u32_const(0);
1503 /// Returns the "next" universe index in order -- this new index
1504 /// is considered to extend all previous universes. This
1505 /// corresponds to entering a `forall` quantifier. So, for
1506 /// example, suppose we have this type in universe `U`:
1509 /// for<'a> fn(&'a u32)
1512 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1513 /// new universe that extends `U` -- in this new universe, we can
1514 /// name the region `'a`, but that region was not nameable from
1515 /// `U` because it was not in scope there.
1516 pub fn next_universe(self) -> UniverseIndex {
1517 UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
1520 /// True if `self` can name a name from `other` -- in other words,
1521 /// if the set of names in `self` is a superset of those in
1523 pub fn can_name(self, other: UniverseIndex) -> bool {
1524 self.private >= other.private
1528 /// The "placeholder index" fully defines a placeholder region.
1529 /// Placeholder regions are identified by both a **universe** as well
1530 /// as a "bound-region" within that universe. The `bound_region` is
1531 /// basically a name -- distinct bound regions within the same
1532 /// universe are just two regions with an unknown relationship to one
1534 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
1535 pub struct Placeholder {
1536 pub universe: UniverseIndex,
1537 pub name: BoundRegion,
1540 /// When type checking, we use the `ParamEnv` to track
1541 /// details about the set of where-clauses that are in scope at this
1542 /// particular point.
1543 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1544 pub struct ParamEnv<'tcx> {
1545 /// Obligations that the caller must satisfy. This is basically
1546 /// the set of bounds on the in-scope type parameters, translated
1547 /// into Obligations, and elaborated and normalized.
1548 pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1550 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1551 /// want `Reveal::All` -- note that this is always paired with an
1552 /// empty environment. To get that, use `ParamEnv::reveal()`.
1553 pub reveal: traits::Reveal,
1556 impl<'tcx> ParamEnv<'tcx> {
1557 /// Construct a trait environment suitable for contexts where
1558 /// there are no where clauses in scope. Hidden types (like `impl
1559 /// Trait`) are left hidden, so this is suitable for ordinary
1561 pub fn empty() -> Self {
1562 Self::new(List::empty(), Reveal::UserFacing)
1565 /// Construct a trait environment with no where clauses in scope
1566 /// where the values of all `impl Trait` and other hidden types
1567 /// are revealed. This is suitable for monomorphized, post-typeck
1568 /// environments like codegen or doing optimizations.
1570 /// NB. If you want to have predicates in scope, use `ParamEnv::new`,
1571 /// or invoke `param_env.with_reveal_all()`.
1572 pub fn reveal_all() -> Self {
1573 Self::new(List::empty(), Reveal::All)
1576 /// Construct a trait environment with the given set of predicates.
1577 pub fn new(caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1580 ty::ParamEnv { caller_bounds, reveal }
1583 /// Returns a new parameter environment with the same clauses, but
1584 /// which "reveals" the true results of projections in all cases
1585 /// (even for associated types that are specializable). This is
1586 /// the desired behavior during codegen and certain other special
1587 /// contexts; normally though we want to use `Reveal::UserFacing`,
1588 /// which is the default.
1589 pub fn with_reveal_all(self) -> Self {
1590 ty::ParamEnv { reveal: Reveal::All, ..self }
1593 /// Returns this same environment but with no caller bounds.
1594 pub fn without_caller_bounds(self) -> Self {
1595 ty::ParamEnv { caller_bounds: List::empty(), ..self }
1598 /// Creates a suitable environment in which to perform trait
1599 /// queries on the given value. When type-checking, this is simply
1600 /// the pair of the environment plus value. But when reveal is set to
1601 /// All, then if `value` does not reference any type parameters, we will
1602 /// pair it with the empty environment. This improves caching and is generally
1605 /// NB: We preserve the environment when type-checking because it
1606 /// is possible for the user to have wacky where-clauses like
1607 /// `where Box<u32>: Copy`, which are clearly never
1608 /// satisfiable. We generally want to behave as if they were true,
1609 /// although the surrounding function is never reachable.
1610 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1612 Reveal::UserFacing => {
1621 || value.needs_infer()
1622 || value.has_param_types()
1623 || value.has_self_ty()
1631 param_env: self.without_caller_bounds(),
1640 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1641 pub struct ParamEnvAnd<'tcx, T> {
1642 pub param_env: ParamEnv<'tcx>,
1646 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1647 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1648 (self.param_env, self.value)
1652 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'gcx, T>
1653 where T: HashStable<StableHashingContext<'a>>
1655 fn hash_stable<W: StableHasherResult>(&self,
1656 hcx: &mut StableHashingContext<'a>,
1657 hasher: &mut StableHasher<W>) {
1663 param_env.hash_stable(hcx, hasher);
1664 value.hash_stable(hcx, hasher);
1668 #[derive(Copy, Clone, Debug)]
1669 pub struct Destructor {
1670 /// The def-id of the destructor method
1675 pub struct AdtFlags: u32 {
1676 const NO_ADT_FLAGS = 0;
1677 const IS_ENUM = 1 << 0;
1678 const IS_PHANTOM_DATA = 1 << 1;
1679 const IS_FUNDAMENTAL = 1 << 2;
1680 const IS_UNION = 1 << 3;
1681 const IS_BOX = 1 << 4;
1682 /// Indicates whether the type is an `Arc`.
1683 const IS_ARC = 1 << 5;
1684 /// Indicates whether the type is an `Rc`.
1685 const IS_RC = 1 << 6;
1686 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1687 /// (i.e., this flag is never set unless this ADT is an enum).
1688 const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 7;
1693 pub struct VariantFlags: u32 {
1694 const NO_VARIANT_FLAGS = 0;
1695 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1696 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1701 pub struct VariantDef {
1702 /// The variant's DefId. If this is a tuple-like struct,
1703 /// this is the DefId of the struct's ctor.
1705 pub name: Name, // struct's name if this is a struct
1706 pub discr: VariantDiscr,
1707 pub fields: Vec<FieldDef>,
1708 pub ctor_kind: CtorKind,
1709 flags: VariantFlags,
1712 impl<'a, 'gcx, 'tcx> VariantDef {
1713 /// Create a new `VariantDef`.
1715 /// - `did` is the DefId used for the variant - for tuple-structs, it is the constructor DefId,
1716 /// and for everything else, it is the variant DefId.
1717 /// - `attribute_def_id` is the DefId that has the variant's attributes.
1718 /// this is the struct DefId for structs, and the variant DefId for variants.
1720 /// Note that we *could* use the constructor DefId, because the constructor attributes
1721 /// redirect to the base attributes, but compiling a small crate requires
1722 /// loading the AdtDefs for all the structs in the universe (e.g. coherence for any
1723 /// built-in trait), and we do not want to load attributes twice.
1725 /// If someone speeds up attribute loading to not be a performance concern, they can
1726 /// remove this hack and use the constructor DefId everywhere.
1727 pub fn new(tcx: TyCtxt<'a, 'gcx, 'tcx>,
1730 discr: VariantDiscr,
1731 fields: Vec<FieldDef>,
1733 ctor_kind: CtorKind,
1734 attribute_def_id: DefId)
1737 debug!("VariantDef::new({:?}, {:?}, {:?}, {:?}, {:?}, {:?}, {:?})", did, name, discr,
1738 fields, adt_kind, ctor_kind, attribute_def_id);
1739 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1740 if adt_kind == AdtKind::Struct && tcx.has_attr(attribute_def_id, "non_exhaustive") {
1741 debug!("found non-exhaustive field list for {:?}", did);
1742 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1755 pub fn is_field_list_non_exhaustive(&self) -> bool {
1756 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1760 impl_stable_hash_for!(struct VariantDef {
1769 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1770 pub enum VariantDiscr {
1771 /// Explicit value for this variant, i.e. `X = 123`.
1772 /// The `DefId` corresponds to the embedded constant.
1775 /// The previous variant's discriminant plus one.
1776 /// For efficiency reasons, the distance from the
1777 /// last `Explicit` discriminant is being stored,
1778 /// or `0` for the first variant, if it has none.
1783 pub struct FieldDef {
1786 pub vis: Visibility,
1789 /// The definition of an abstract data type - a struct or enum.
1791 /// These are all interned (by intern_adt_def) into the adt_defs
1795 pub variants: Vec<VariantDef>,
1797 pub repr: ReprOptions,
1800 impl PartialOrd for AdtDef {
1801 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1802 Some(self.cmp(&other))
1806 /// There should be only one AdtDef for each `did`, therefore
1807 /// it is fine to implement `Ord` only based on `did`.
1808 impl Ord for AdtDef {
1809 fn cmp(&self, other: &AdtDef) -> Ordering {
1810 self.did.cmp(&other.did)
1814 impl PartialEq for AdtDef {
1815 // AdtDef are always interned and this is part of TyS equality
1817 fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) }
1820 impl Eq for AdtDef {}
1822 impl Hash for AdtDef {
1824 fn hash<H: Hasher>(&self, s: &mut H) {
1825 (self as *const AdtDef).hash(s)
1829 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1830 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1835 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1838 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1839 fn hash_stable<W: StableHasherResult>(&self,
1840 hcx: &mut StableHashingContext<'a>,
1841 hasher: &mut StableHasher<W>) {
1843 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> =
1844 RefCell::new(FxHashMap());
1847 let hash: Fingerprint = CACHE.with(|cache| {
1848 let addr = self as *const AdtDef as usize;
1849 *cache.borrow_mut().entry(addr).or_insert_with(|| {
1857 let mut hasher = StableHasher::new();
1858 did.hash_stable(hcx, &mut hasher);
1859 variants.hash_stable(hcx, &mut hasher);
1860 flags.hash_stable(hcx, &mut hasher);
1861 repr.hash_stable(hcx, &mut hasher);
1867 hash.hash_stable(hcx, hasher);
1871 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
1872 pub enum AdtKind { Struct, Union, Enum }
1874 impl Into<DataTypeKind> for AdtKind {
1875 fn into(self) -> DataTypeKind {
1877 AdtKind::Struct => DataTypeKind::Struct,
1878 AdtKind::Union => DataTypeKind::Union,
1879 AdtKind::Enum => DataTypeKind::Enum,
1885 #[derive(RustcEncodable, RustcDecodable, Default)]
1886 pub struct ReprFlags: u8 {
1887 const IS_C = 1 << 0;
1888 const IS_SIMD = 1 << 1;
1889 const IS_TRANSPARENT = 1 << 2;
1890 // Internal only for now. If true, don't reorder fields.
1891 const IS_LINEAR = 1 << 3;
1893 // Any of these flags being set prevent field reordering optimisation.
1894 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1895 ReprFlags::IS_SIMD.bits |
1896 ReprFlags::IS_LINEAR.bits;
1900 impl_stable_hash_for!(struct ReprFlags {
1906 /// Represents the repr options provided by the user,
1907 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1908 pub struct ReprOptions {
1909 pub int: Option<attr::IntType>,
1912 pub flags: ReprFlags,
1915 impl_stable_hash_for!(struct ReprOptions {
1923 pub fn new(tcx: TyCtxt<'_, '_, '_>, did: DefId) -> ReprOptions {
1924 let mut flags = ReprFlags::empty();
1925 let mut size = None;
1926 let mut max_align = 0;
1927 let mut min_pack = 0;
1928 for attr in tcx.get_attrs(did).iter() {
1929 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1930 flags.insert(match r {
1931 attr::ReprC => ReprFlags::IS_C,
1932 attr::ReprPacked(pack) => {
1933 min_pack = if min_pack > 0 {
1934 cmp::min(pack, min_pack)
1940 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
1941 attr::ReprSimd => ReprFlags::IS_SIMD,
1942 attr::ReprInt(i) => {
1946 attr::ReprAlign(align) => {
1947 max_align = cmp::max(align, max_align);
1954 // This is here instead of layout because the choice must make it into metadata.
1955 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1956 flags.insert(ReprFlags::IS_LINEAR);
1958 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
1962 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1964 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1966 pub fn packed(&self) -> bool { self.pack > 0 }
1968 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
1970 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1972 pub fn discr_type(&self) -> attr::IntType {
1973 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
1976 /// Returns true if this `#[repr()]` should inhabit "smart enum
1977 /// layout" optimizations, such as representing `Foo<&T>` as a
1979 pub fn inhibit_enum_layout_opt(&self) -> bool {
1980 self.c() || self.int.is_some()
1983 /// Returns true if this `#[repr()]` should inhibit struct field reordering
1984 /// optimizations, such as with repr(C) or repr(packed(1)).
1985 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
1986 !(self.flags & ReprFlags::IS_UNOPTIMISABLE).is_empty() || (self.pack == 1)
1990 impl<'a, 'gcx, 'tcx> AdtDef {
1991 fn new(tcx: TyCtxt<'_, '_, '_>,
1994 variants: Vec<VariantDef>,
1995 repr: ReprOptions) -> Self {
1996 debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
1997 let mut flags = AdtFlags::NO_ADT_FLAGS;
1998 let attrs = tcx.get_attrs(did);
1999 if attr::contains_name(&attrs, "fundamental") {
2000 flags = flags | AdtFlags::IS_FUNDAMENTAL;
2002 if Some(did) == tcx.lang_items().phantom_data() {
2003 flags = flags | AdtFlags::IS_PHANTOM_DATA;
2005 if Some(did) == tcx.lang_items().owned_box() {
2006 flags = flags | AdtFlags::IS_BOX;
2008 if Some(did) == tcx.lang_items().arc() {
2009 flags = flags | AdtFlags::IS_ARC;
2011 if Some(did) == tcx.lang_items().rc() {
2012 flags = flags | AdtFlags::IS_RC;
2014 if kind == AdtKind::Enum && tcx.has_attr(did, "non_exhaustive") {
2015 debug!("found non-exhaustive variant list for {:?}", did);
2016 flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
2019 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
2020 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
2021 AdtKind::Struct => {}
2032 pub fn is_struct(&self) -> bool {
2033 !self.is_union() && !self.is_enum()
2037 pub fn is_union(&self) -> bool {
2038 self.flags.intersects(AdtFlags::IS_UNION)
2042 pub fn is_enum(&self) -> bool {
2043 self.flags.intersects(AdtFlags::IS_ENUM)
2047 pub fn is_variant_list_non_exhaustive(&self) -> bool {
2048 self.flags.intersects(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
2051 /// Returns the kind of the ADT - Struct or Enum.
2053 pub fn adt_kind(&self) -> AdtKind {
2056 } else if self.is_union() {
2063 pub fn descr(&self) -> &'static str {
2064 match self.adt_kind() {
2065 AdtKind::Struct => "struct",
2066 AdtKind::Union => "union",
2067 AdtKind::Enum => "enum",
2071 pub fn variant_descr(&self) -> &'static str {
2072 match self.adt_kind() {
2073 AdtKind::Struct => "struct",
2074 AdtKind::Union => "union",
2075 AdtKind::Enum => "variant",
2079 /// Returns whether this type is #[fundamental] for the purposes
2080 /// of coherence checking.
2082 pub fn is_fundamental(&self) -> bool {
2083 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
2086 /// Returns true if this is PhantomData<T>.
2088 pub fn is_phantom_data(&self) -> bool {
2089 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
2092 /// Returns `true` if this is `Arc<T>`.
2093 pub fn is_arc(&self) -> bool {
2094 self.flags.intersects(AdtFlags::IS_ARC)
2097 /// Returns `true` if this is `Rc<T>`.
2098 pub fn is_rc(&self) -> bool {
2099 self.flags.intersects(AdtFlags::IS_RC)
2102 /// Returns true if this is Box<T>.
2104 pub fn is_box(&self) -> bool {
2105 self.flags.intersects(AdtFlags::IS_BOX)
2108 /// Returns whether this type has a destructor.
2109 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
2110 self.destructor(tcx).is_some()
2113 /// Asserts this is a struct or union and returns its unique variant.
2114 pub fn non_enum_variant(&self) -> &VariantDef {
2115 assert!(self.is_struct() || self.is_union());
2120 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
2121 tcx.predicates_of(self.did)
2124 /// Returns an iterator over all fields contained
2127 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
2128 self.variants.iter().flat_map(|v| v.fields.iter())
2131 pub fn is_payloadfree(&self) -> bool {
2132 !self.variants.is_empty() &&
2133 self.variants.iter().all(|v| v.fields.is_empty())
2136 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
2139 .find(|v| v.did == vid)
2140 .expect("variant_with_id: unknown variant")
2143 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
2146 .position(|v| v.did == vid)
2147 .expect("variant_index_with_id: unknown variant")
2150 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
2152 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
2153 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
2154 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) |
2155 Def::SelfCtor(..) => self.non_enum_variant(),
2156 _ => bug!("unexpected def {:?} in variant_of_def", def)
2161 pub fn eval_explicit_discr(
2163 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2165 ) -> Option<Discr<'tcx>> {
2166 let param_env = ParamEnv::empty();
2167 let repr_type = self.repr.discr_type();
2168 let substs = Substs::identity_for_item(tcx.global_tcx(), expr_did);
2169 let instance = ty::Instance::new(expr_did, substs);
2170 let cid = GlobalId {
2174 match tcx.const_eval(param_env.and(cid)) {
2176 // FIXME: Find the right type and use it instead of `val.ty` here
2177 if let Some(b) = val.assert_bits(tcx.global_tcx(), param_env.and(val.ty)) {
2178 trace!("discriminants: {} ({:?})", b, repr_type);
2184 info!("invalid enum discriminant: {:#?}", val);
2185 ::mir::interpret::struct_error(
2186 tcx.at(tcx.def_span(expr_did)),
2187 "constant evaluation of enum discriminant resulted in non-integer",
2193 err.report_as_error(
2194 tcx.at(tcx.def_span(expr_did)),
2195 "could not evaluate enum discriminant",
2197 if !expr_did.is_local() {
2198 span_bug!(tcx.def_span(expr_did),
2199 "variant discriminant evaluation succeeded \
2200 in its crate but failed locally");
2208 pub fn discriminants(
2210 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2211 ) -> impl Iterator<Item=Discr<'tcx>> + Captures<'gcx> + 'a {
2212 let repr_type = self.repr.discr_type();
2213 let initial = repr_type.initial_discriminant(tcx.global_tcx());
2214 let mut prev_discr = None::<Discr<'tcx>>;
2215 self.variants.iter().map(move |v| {
2216 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
2217 if let VariantDiscr::Explicit(expr_did) = v.discr {
2218 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
2222 prev_discr = Some(discr);
2228 /// Compute the discriminant value used by a specific variant.
2229 /// Unlike `discriminants`, this is (amortized) constant-time,
2230 /// only doing at most one query for evaluating an explicit
2231 /// discriminant (the last one before the requested variant),
2232 /// assuming there are no constant-evaluation errors there.
2233 pub fn discriminant_for_variant(&self,
2234 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2235 variant_index: usize)
2237 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2238 let explicit_value = val
2239 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2240 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx.global_tcx()));
2241 explicit_value.checked_add(tcx, offset as u128).0
2244 /// Yields a DefId for the discriminant and an offset to add to it
2245 /// Alternatively, if there is no explicit discriminant, returns the
2246 /// inferred discriminant directly
2247 pub fn discriminant_def_for_variant(
2249 variant_index: usize,
2250 ) -> (Option<DefId>, usize) {
2251 let mut explicit_index = variant_index;
2254 match self.variants[explicit_index].discr {
2255 ty::VariantDiscr::Relative(0) => {
2259 ty::VariantDiscr::Relative(distance) => {
2260 explicit_index -= distance;
2262 ty::VariantDiscr::Explicit(did) => {
2263 expr_did = Some(did);
2268 (expr_did, variant_index - explicit_index)
2271 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
2272 tcx.adt_destructor(self.did)
2275 /// Returns a list of types such that `Self: Sized` if and only
2276 /// if that type is Sized, or `TyErr` if this type is recursive.
2278 /// Oddly enough, checking that the sized-constraint is Sized is
2279 /// actually more expressive than checking all members:
2280 /// the Sized trait is inductive, so an associated type that references
2281 /// Self would prevent its containing ADT from being Sized.
2283 /// Due to normalization being eager, this applies even if
2284 /// the associated type is behind a pointer, e.g. issue #31299.
2285 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
2286 match tcx.try_adt_sized_constraint(DUMMY_SP, self.did) {
2289 debug!("adt_sized_constraint: {:?} is recursive", self);
2290 // This should be reported as an error by `check_representable`.
2292 // Consider the type as Sized in the meanwhile to avoid
2293 // further errors. Delay our `bug` diagnostic here to get
2294 // emitted later as well in case we accidentally otherwise don't
2297 tcx.intern_type_list(&[tcx.types.err])
2302 fn sized_constraint_for_ty(&self,
2303 tcx: TyCtxt<'a, 'tcx, 'tcx>,
2306 let result = match ty.sty {
2307 Bool | Char | Int(..) | Uint(..) | Float(..) |
2308 RawPtr(..) | Ref(..) | FnDef(..) | FnPtr(_) |
2309 Array(..) | Closure(..) | Generator(..) | Never => {
2318 GeneratorWitness(..) => {
2319 // these are never sized - return the target type
2326 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
2330 Adt(adt, substs) => {
2332 let adt_tys = adt.sized_constraint(tcx);
2333 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
2336 .map(|ty| ty.subst(tcx, substs))
2337 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2341 Projection(..) | Opaque(..) => {
2342 // must calculate explicitly.
2343 // FIXME: consider special-casing always-Sized projections
2347 UnnormalizedProjection(..) => bug!("only used with chalk-engine"),
2350 // perf hack: if there is a `T: Sized` bound, then
2351 // we know that `T` is Sized and do not need to check
2354 let sized_trait = match tcx.lang_items().sized_trait() {
2356 _ => return vec![ty]
2358 let sized_predicate = Binder::dummy(TraitRef {
2359 def_id: sized_trait,
2360 substs: tcx.mk_substs_trait(ty, &[])
2362 let predicates = tcx.predicates_of(self.did).predicates;
2363 if predicates.into_iter().any(|(p, _)| p == sized_predicate) {
2371 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2375 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2380 impl<'a, 'gcx, 'tcx> FieldDef {
2381 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
2382 tcx.type_of(self.did).subst(tcx, subst)
2386 /// Represents the various closure traits in the Rust language. This
2387 /// will determine the type of the environment (`self`, in the
2388 /// desuaring) argument that the closure expects.
2390 /// You can get the environment type of a closure using
2391 /// `tcx.closure_env_ty()`.
2392 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
2393 pub enum ClosureKind {
2394 // Warning: Ordering is significant here! The ordering is chosen
2395 // because the trait Fn is a subtrait of FnMut and so in turn, and
2396 // hence we order it so that Fn < FnMut < FnOnce.
2402 impl<'a, 'tcx> ClosureKind {
2403 // This is the initial value used when doing upvar inference.
2404 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2406 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
2408 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
2409 ClosureKind::FnMut => {
2410 tcx.require_lang_item(FnMutTraitLangItem)
2412 ClosureKind::FnOnce => {
2413 tcx.require_lang_item(FnOnceTraitLangItem)
2418 /// True if this a type that impls this closure kind
2419 /// must also implement `other`.
2420 pub fn extends(self, other: ty::ClosureKind) -> bool {
2421 match (self, other) {
2422 (ClosureKind::Fn, ClosureKind::Fn) => true,
2423 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2424 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2425 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2426 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2427 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2432 /// Returns the representative scalar type for this closure kind.
2433 /// See `TyS::to_opt_closure_kind` for more details.
2434 pub fn to_ty(self, tcx: TyCtxt<'_, '_, 'tcx>) -> Ty<'tcx> {
2436 ty::ClosureKind::Fn => tcx.types.i8,
2437 ty::ClosureKind::FnMut => tcx.types.i16,
2438 ty::ClosureKind::FnOnce => tcx.types.i32,
2443 impl<'tcx> TyS<'tcx> {
2444 /// Iterator that walks `self` and any types reachable from
2445 /// `self`, in depth-first order. Note that just walks the types
2446 /// that appear in `self`, it does not descend into the fields of
2447 /// structs or variants. For example:
2450 /// isize => { isize }
2451 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2452 /// [isize] => { [isize], isize }
2454 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2455 TypeWalker::new(self)
2458 /// Iterator that walks the immediate children of `self`. Hence
2459 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2460 /// (but not `i32`, like `walk`).
2461 pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
2462 walk::walk_shallow(self)
2465 /// Walks `ty` and any types appearing within `ty`, invoking the
2466 /// callback `f` on each type. If the callback returns false, then the
2467 /// children of the current type are ignored.
2469 /// Note: prefer `ty.walk()` where possible.
2470 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2471 where F : FnMut(Ty<'tcx>) -> bool
2473 let mut walker = self.walk();
2474 while let Some(ty) = walker.next() {
2476 walker.skip_current_subtree();
2483 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2485 hir::MutMutable => MutBorrow,
2486 hir::MutImmutable => ImmBorrow,
2490 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2491 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2492 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2494 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2496 MutBorrow => hir::MutMutable,
2497 ImmBorrow => hir::MutImmutable,
2499 // We have no type corresponding to a unique imm borrow, so
2500 // use `&mut`. It gives all the capabilities of an `&uniq`
2501 // and hence is a safe "over approximation".
2502 UniqueImmBorrow => hir::MutMutable,
2506 pub fn to_user_str(&self) -> &'static str {
2508 MutBorrow => "mutable",
2509 ImmBorrow => "immutable",
2510 UniqueImmBorrow => "uniquely immutable",
2515 #[derive(Debug, Clone)]
2516 pub enum Attributes<'gcx> {
2517 Owned(Lrc<[ast::Attribute]>),
2518 Borrowed(&'gcx [ast::Attribute])
2521 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2522 type Target = [ast::Attribute];
2524 fn deref(&self) -> &[ast::Attribute] {
2526 &Attributes::Owned(ref data) => &data,
2527 &Attributes::Borrowed(data) => data
2532 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2533 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2534 self.typeck_tables_of(self.hir.body_owner_def_id(body))
2537 /// Returns an iterator of the def-ids for all body-owners in this
2538 /// crate. If you would prefer to iterate over the bodies
2539 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
2542 ) -> impl Iterator<Item = DefId> + Captures<'tcx> + Captures<'gcx> + 'a {
2546 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
2549 pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
2550 par_iter(&self.hir.krate().body_ids).for_each(|&body_id| {
2551 f(self.hir.body_owner_def_id(body_id))
2555 pub fn expr_span(self, id: NodeId) -> Span {
2556 match self.hir.find(id) {
2557 Some(Node::Expr(e)) => {
2561 bug!("Node id {} is not an expr: {:?}", id, f);
2564 bug!("Node id {} is not present in the node map", id);
2569 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2570 self.associated_items(id)
2571 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2575 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2576 self.associated_items(did).any(|item| {
2577 item.relevant_for_never()
2581 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2582 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2583 match self.hir.get(node_id) {
2584 Node::TraitItem(_) | Node::ImplItem(_) => true,
2588 match self.describe_def(def_id).expect("no def for def-id") {
2589 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2594 if is_associated_item {
2595 Some(self.associated_item(def_id))
2601 fn associated_item_from_trait_item_ref(self,
2602 parent_def_id: DefId,
2603 parent_vis: &hir::Visibility,
2604 trait_item_ref: &hir::TraitItemRef)
2606 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2607 let (kind, has_self) = match trait_item_ref.kind {
2608 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2609 hir::AssociatedItemKind::Method { has_self } => {
2610 (ty::AssociatedKind::Method, has_self)
2612 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2613 hir::AssociatedItemKind::Existential => bug!("only impls can have existentials"),
2617 ident: trait_item_ref.ident,
2619 // Visibility of trait items is inherited from their traits.
2620 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2621 defaultness: trait_item_ref.defaultness,
2623 container: TraitContainer(parent_def_id),
2624 method_has_self_argument: has_self
2628 fn associated_item_from_impl_item_ref(self,
2629 parent_def_id: DefId,
2630 impl_item_ref: &hir::ImplItemRef)
2632 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2633 let (kind, has_self) = match impl_item_ref.kind {
2634 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2635 hir::AssociatedItemKind::Method { has_self } => {
2636 (ty::AssociatedKind::Method, has_self)
2638 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2639 hir::AssociatedItemKind::Existential => (ty::AssociatedKind::Existential, false),
2643 ident: impl_item_ref.ident,
2645 // Visibility of trait impl items doesn't matter.
2646 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2647 defaultness: impl_item_ref.defaultness,
2649 container: ImplContainer(parent_def_id),
2650 method_has_self_argument: has_self
2654 pub fn field_index(self, node_id: NodeId, tables: &TypeckTables<'_>) -> usize {
2655 let hir_id = self.hir.node_to_hir_id(node_id);
2656 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2659 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2660 variant.fields.iter().position(|field| {
2661 self.adjust_ident(ident, variant.did, DUMMY_NODE_ID).0 == field.ident.modern()
2665 pub fn associated_items(
2668 ) -> impl Iterator<Item = AssociatedItem> + 'a {
2669 let def_ids = self.associated_item_def_ids(def_id);
2670 Box::new((0..def_ids.len()).map(move |i| self.associated_item(def_ids[i])))
2671 as Box<dyn Iterator<Item = AssociatedItem> + 'a>
2674 /// Returns true if the impls are the same polarity and the trait either
2675 /// has no items or is annotated #[marker] and prevents item overrides.
2676 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2677 if self.features().overlapping_marker_traits {
2678 let trait1_is_empty = self.impl_trait_ref(def_id1)
2679 .map_or(false, |trait_ref| {
2680 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2682 let trait2_is_empty = self.impl_trait_ref(def_id2)
2683 .map_or(false, |trait_ref| {
2684 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2686 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2689 } else if self.features().marker_trait_attr {
2690 let is_marker_impl = |def_id: DefId| -> bool {
2691 let trait_ref = self.impl_trait_ref(def_id);
2692 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2694 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2695 && is_marker_impl(def_id1)
2696 && is_marker_impl(def_id2)
2702 // Returns `ty::VariantDef` if `def` refers to a struct,
2703 // or variant or their constructors, panics otherwise.
2704 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2706 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2707 let enum_did = self.parent_def_id(did).unwrap();
2708 self.adt_def(enum_did).variant_with_id(did)
2710 Def::Struct(did) | Def::Union(did) => {
2711 self.adt_def(did).non_enum_variant()
2713 Def::StructCtor(ctor_did, ..) => {
2714 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2715 self.adt_def(did).non_enum_variant()
2717 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2721 /// Given a `VariantDef`, returns the def-id of the `AdtDef` of which it is a part.
2722 pub fn adt_def_id_of_variant(self, variant_def: &'tcx VariantDef) -> DefId {
2723 let def_key = self.def_key(variant_def.did);
2724 match def_key.disambiguated_data.data {
2725 // for enum variants and tuple structs, the def-id of the ADT itself
2726 // is the *parent* of the variant
2727 DefPathData::EnumVariant(..) | DefPathData::StructCtor =>
2728 DefId { krate: variant_def.did.krate, index: def_key.parent.unwrap() },
2730 // otherwise, for structs and unions, they share a def-id
2731 _ => variant_def.did,
2735 pub fn item_name(self, id: DefId) -> InternedString {
2736 if id.index == CRATE_DEF_INDEX {
2737 self.original_crate_name(id.krate).as_interned_str()
2739 let def_key = self.def_key(id);
2740 // The name of a StructCtor is that of its struct parent.
2741 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2742 self.item_name(DefId {
2744 index: def_key.parent.unwrap()
2747 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2748 bug!("item_name: no name for {:?}", self.def_path(id));
2754 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2755 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2759 ty::InstanceDef::Item(did) => {
2760 self.optimized_mir(did)
2762 ty::InstanceDef::Intrinsic(..) |
2763 ty::InstanceDef::FnPtrShim(..) |
2764 ty::InstanceDef::Virtual(..) |
2765 ty::InstanceDef::ClosureOnceShim { .. } |
2766 ty::InstanceDef::DropGlue(..) |
2767 ty::InstanceDef::CloneShim(..) => {
2768 self.mir_shims(instance)
2773 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2774 /// Returns None if there is no MIR for the DefId
2775 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2776 if self.is_mir_available(did) {
2777 Some(self.optimized_mir(did))
2783 /// Get the attributes of a definition.
2784 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2785 if let Some(id) = self.hir.as_local_node_id(did) {
2786 Attributes::Borrowed(self.hir.attrs(id))
2788 Attributes::Owned(self.item_attrs(did))
2792 /// Determine whether an item is annotated with an attribute
2793 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2794 attr::contains_name(&self.get_attrs(did), attr)
2797 /// Returns true if this is an `auto trait`.
2798 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
2799 self.trait_def(trait_def_id).has_auto_impl
2802 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
2803 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
2806 /// Given the def_id of an impl, return the def_id of the trait it implements.
2807 /// If it implements no trait, return `None`.
2808 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2809 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2812 /// If the given def ID describes a method belonging to an impl, return the
2813 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2814 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2815 let item = if def_id.krate != LOCAL_CRATE {
2816 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2817 Some(self.associated_item(def_id))
2822 self.opt_associated_item(def_id)
2825 item.and_then(|trait_item|
2826 match trait_item.container {
2827 TraitContainer(_) => None,
2828 ImplContainer(def_id) => Some(def_id),
2833 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2834 /// with the name of the crate containing the impl.
2835 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2836 if impl_did.is_local() {
2837 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2838 Ok(self.hir.span(node_id))
2840 Err(self.crate_name(impl_did.krate))
2844 // Hygienically compare a use-site name (`use_name`) for a field or an associated item with its
2845 // supposed definition name (`def_name`). The method also needs `DefId` of the supposed
2846 // definition's parent/scope to perform comparison.
2847 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
2848 self.adjust_ident(use_name, def_parent_def_id, DUMMY_NODE_ID).0 == def_name.modern()
2851 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
2852 ident = ident.modern();
2853 let target_expansion = match scope.krate {
2854 LOCAL_CRATE => self.hir.definitions().expansion_that_defined(scope.index),
2857 let scope = match ident.span.adjust(target_expansion) {
2858 Some(actual_expansion) =>
2859 self.hir.definitions().parent_module_of_macro_def(actual_expansion),
2860 None if block == DUMMY_NODE_ID => DefId::local(CRATE_DEF_INDEX), // Dummy DefId
2861 None => self.hir.get_module_parent(block),
2867 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2868 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2869 F: FnOnce(&[hir::Freevar]) -> T,
2871 let def_id = self.hir.local_def_id(fid);
2872 match self.freevars(def_id) {
2879 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> AssociatedItem {
2880 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2881 let parent_id = tcx.hir.get_parent(id);
2882 let parent_def_id = tcx.hir.local_def_id(parent_id);
2883 let parent_item = tcx.hir.expect_item(parent_id);
2884 match parent_item.node {
2885 hir::ItemKind::Impl(.., ref impl_item_refs) => {
2886 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2887 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2889 debug_assert_eq!(assoc_item.def_id, def_id);
2894 hir::ItemKind::Trait(.., ref trait_item_refs) => {
2895 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2896 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2899 debug_assert_eq!(assoc_item.def_id, def_id);
2907 span_bug!(parent_item.span,
2908 "unexpected parent of trait or impl item or item not found: {:?}",
2912 /// Calculates the Sized-constraint.
2914 /// In fact, there are only a few options for the types in the constraint:
2915 /// - an obviously-unsized type
2916 /// - a type parameter or projection whose Sizedness can't be known
2917 /// - a tuple of type parameters or projections, if there are multiple
2919 /// - a Error, if a type contained itself. The representability
2920 /// check should catch this case.
2921 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2923 -> &'tcx [Ty<'tcx>] {
2924 let def = tcx.adt_def(def_id);
2926 let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| {
2929 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2932 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2937 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2939 -> Lrc<Vec<DefId>> {
2940 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2941 let item = tcx.hir.expect_item(id);
2942 let vec: Vec<_> = match item.node {
2943 hir::ItemKind::Trait(.., ref trait_item_refs) => {
2944 trait_item_refs.iter()
2945 .map(|trait_item_ref| trait_item_ref.id)
2946 .map(|id| tcx.hir.local_def_id(id.node_id))
2949 hir::ItemKind::Impl(.., ref impl_item_refs) => {
2950 impl_item_refs.iter()
2951 .map(|impl_item_ref| impl_item_ref.id)
2952 .map(|id| tcx.hir.local_def_id(id.node_id))
2955 hir::ItemKind::TraitAlias(..) => vec![],
2956 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2961 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
2962 tcx.hir.span_if_local(def_id).unwrap()
2965 /// If the given def ID describes an item belonging to a trait,
2966 /// return the ID of the trait that the trait item belongs to.
2967 /// Otherwise, return `None`.
2968 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
2969 tcx.opt_associated_item(def_id)
2970 .and_then(|associated_item| {
2971 match associated_item.container {
2972 TraitContainer(def_id) => Some(def_id),
2973 ImplContainer(_) => None
2978 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition
2979 pub fn is_impl_trait_defn(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> Option<DefId> {
2980 if let Some(node_id) = tcx.hir.as_local_node_id(def_id) {
2981 if let Node::Item(item) = tcx.hir.get(node_id) {
2982 if let hir::ItemKind::Existential(ref exist_ty) = item.node {
2983 return exist_ty.impl_trait_fn;
2990 /// See `ParamEnv` struct def'n for details.
2991 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2995 // The param_env of an impl Trait type is its defining function's param_env
2996 if let Some(parent) = is_impl_trait_defn(tcx, def_id) {
2997 return param_env(tcx, parent);
2999 // Compute the bounds on Self and the type parameters.
3001 let InstantiatedPredicates { predicates } =
3002 tcx.predicates_of(def_id).instantiate_identity(tcx);
3004 // Finally, we have to normalize the bounds in the environment, in
3005 // case they contain any associated type projections. This process
3006 // can yield errors if the put in illegal associated types, like
3007 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
3008 // report these errors right here; this doesn't actually feel
3009 // right to me, because constructing the environment feels like a
3010 // kind of a "idempotent" action, but I'm not sure where would be
3011 // a better place. In practice, we construct environments for
3012 // every fn once during type checking, and we'll abort if there
3013 // are any errors at that point, so after type checking you can be
3014 // sure that this will succeed without errors anyway.
3016 let unnormalized_env = ty::ParamEnv::new(tcx.intern_predicates(&predicates),
3017 traits::Reveal::UserFacing);
3019 let body_id = tcx.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
3020 tcx.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_id)
3022 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
3023 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
3026 fn crate_disambiguator<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3027 crate_num: CrateNum) -> CrateDisambiguator {
3028 assert_eq!(crate_num, LOCAL_CRATE);
3029 tcx.sess.local_crate_disambiguator()
3032 fn original_crate_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3033 crate_num: CrateNum) -> Symbol {
3034 assert_eq!(crate_num, LOCAL_CRATE);
3035 tcx.crate_name.clone()
3038 fn crate_hash<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3039 crate_num: CrateNum)
3041 assert_eq!(crate_num, LOCAL_CRATE);
3045 fn instance_def_size_estimate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3046 instance_def: InstanceDef<'tcx>)
3048 match instance_def {
3049 InstanceDef::Item(..) |
3050 InstanceDef::DropGlue(..) => {
3051 let mir = tcx.instance_mir(instance_def);
3052 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
3054 // Estimate the size of other compiler-generated shims to be 1.
3059 pub fn provide(providers: &mut ty::query::Providers<'_>) {
3060 context::provide(providers);
3061 erase_regions::provide(providers);
3062 layout::provide(providers);
3063 util::provide(providers);
3064 constness::provide(providers);
3065 *providers = ty::query::Providers {
3067 associated_item_def_ids,
3068 adt_sized_constraint,
3072 crate_disambiguator,
3073 original_crate_name,
3075 trait_impls_of: trait_def::trait_impls_of_provider,
3076 instance_def_size_estimate,
3081 /// A map for the local crate mapping each type to a vector of its
3082 /// inherent impls. This is not meant to be used outside of coherence;
3083 /// rather, you should request the vector for a specific type via
3084 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
3085 /// (constructing this map requires touching the entire crate).
3086 #[derive(Clone, Debug)]
3087 pub struct CrateInherentImpls {
3088 pub inherent_impls: DefIdMap<Lrc<Vec<DefId>>>,
3091 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
3092 pub struct SymbolName {
3093 // FIXME: we don't rely on interning or equality here - better have
3094 // this be a `&'tcx str`.
3095 pub name: InternedString
3098 impl_stable_hash_for!(struct self::SymbolName {
3103 pub fn new(name: &str) -> SymbolName {
3105 name: Symbol::intern(name).as_interned_str()
3109 pub fn as_str(&self) -> LocalInternedString {
3114 impl fmt::Display for SymbolName {
3115 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3116 fmt::Display::fmt(&self.name, fmt)
3120 impl fmt::Debug for SymbolName {
3121 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3122 fmt::Display::fmt(&self.name, fmt)