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, ErrorHandled};
31 use mir::GeneratorLayout;
32 use session::CrateDisambiguator;
33 use traits::{self, Reveal};
35 use ty::layout::VariantIdx;
36 use ty::subst::{Subst, Substs};
37 use ty::util::{IntTypeExt, Discr};
38 use ty::walk::TypeWalker;
39 use util::captures::Captures;
40 use util::nodemap::{NodeSet, DefIdMap, FxHashMap};
41 use arena::SyncDroplessArena;
42 use session::DataTypeKind;
44 use serialize::{self, Encodable, Encoder};
45 use std::cell::RefCell;
46 use std::cmp::{self, Ordering};
48 use std::hash::{Hash, Hasher};
50 use rustc_data_structures::sync::{self, Lrc, ParallelIterator, par_iter};
52 use std::vec::IntoIter;
54 use syntax::ast::{self, DUMMY_NODE_ID, Name, Ident, NodeId};
56 use syntax::ext::hygiene::Mark;
57 use syntax::symbol::{keywords, Symbol, LocalInternedString, InternedString};
58 use syntax_pos::{DUMMY_SP, Span};
61 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
62 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
67 pub use self::sty::{Binder, BoundTy, BoundTyKind, BoundVar, DebruijnIndex, INNERMOST};
68 pub use self::sty::{FnSig, GenSig, CanonicalPolyFnSig, PolyFnSig, PolyGenSig};
69 pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
70 pub use self::sty::{ClosureSubsts, GeneratorSubsts, UpvarSubsts, TypeAndMut};
71 pub use self::sty::{TraitRef, TyKind, PolyTraitRef};
72 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
73 pub use self::sty::{ExistentialProjection, PolyExistentialProjection, Const};
74 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
75 pub use self::sty::RegionKind;
76 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid};
77 pub use self::sty::BoundRegion::*;
78 pub use self::sty::InferTy::*;
79 pub use self::sty::RegionKind::*;
80 pub use self::sty::TyKind::*;
82 pub use self::binding::BindingMode;
83 pub use self::binding::BindingMode::*;
85 pub use self::context::{TyCtxt, FreeRegionInfo, GlobalArenas, AllArenas, tls, keep_local};
86 pub use self::context::{Lift, TypeckTables};
88 pub use self::instance::{Instance, InstanceDef};
90 pub use self::trait_def::TraitDef;
92 pub use self::query::queries;
104 pub mod inhabitedness;
121 mod structural_impls;
126 /// The complete set of all analyses described in this module. This is
127 /// produced by the driver and fed to codegen and later passes.
129 /// NB: These contents are being migrated into queries using the
130 /// *on-demand* infrastructure.
132 pub struct CrateAnalysis {
133 pub access_levels: Lrc<AccessLevels>,
135 pub glob_map: Option<hir::GlobMap>,
139 pub struct Resolutions {
140 pub freevars: FreevarMap,
141 pub trait_map: TraitMap,
142 pub maybe_unused_trait_imports: NodeSet,
143 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
144 pub export_map: ExportMap,
145 /// Extern prelude entries. The value is `true` if the entry was introduced
146 /// via `extern crate` item and not `--extern` option or compiler built-in.
147 pub extern_prelude: FxHashMap<Name, bool>,
150 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
151 pub enum AssociatedItemContainer {
152 TraitContainer(DefId),
153 ImplContainer(DefId),
156 impl AssociatedItemContainer {
157 /// Asserts that this is the def-id of an associated item declared
158 /// in a trait, and returns the trait def-id.
159 pub fn assert_trait(&self) -> DefId {
161 TraitContainer(id) => id,
162 _ => bug!("associated item has wrong container type: {:?}", self)
166 pub fn id(&self) -> DefId {
168 TraitContainer(id) => id,
169 ImplContainer(id) => id,
174 /// The "header" of an impl is everything outside the body: a Self type, a trait
175 /// ref (in the case of a trait impl), and a set of predicates (from the
176 /// bounds/where clauses).
177 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
178 pub struct ImplHeader<'tcx> {
179 pub impl_def_id: DefId,
180 pub self_ty: Ty<'tcx>,
181 pub trait_ref: Option<TraitRef<'tcx>>,
182 pub predicates: Vec<Predicate<'tcx>>,
185 #[derive(Copy, Clone, Debug, PartialEq)]
186 pub struct AssociatedItem {
189 pub kind: AssociatedKind,
191 pub defaultness: hir::Defaultness,
192 pub container: AssociatedItemContainer,
194 /// Whether this is a method with an explicit self
195 /// as its first argument, allowing method calls.
196 pub method_has_self_argument: bool,
199 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash, RustcEncodable, RustcDecodable)]
200 pub enum AssociatedKind {
207 impl AssociatedItem {
208 pub fn def(&self) -> Def {
210 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
211 AssociatedKind::Method => Def::Method(self.def_id),
212 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
213 AssociatedKind::Existential => Def::AssociatedExistential(self.def_id),
217 /// Tests whether the associated item admits a non-trivial implementation
219 pub fn relevant_for_never<'tcx>(&self) -> bool {
221 AssociatedKind::Existential |
222 AssociatedKind::Const |
223 AssociatedKind::Type => true,
224 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
225 AssociatedKind::Method => !self.method_has_self_argument,
229 pub fn signature<'a, 'tcx>(&self, tcx: &TyCtxt<'a, 'tcx, 'tcx>) -> String {
231 ty::AssociatedKind::Method => {
232 // We skip the binder here because the binder would deanonymize all
233 // late-bound regions, and we don't want method signatures to show up
234 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
235 // regions just fine, showing `fn(&MyType)`.
236 tcx.fn_sig(self.def_id).skip_binder().to_string()
238 ty::AssociatedKind::Type => format!("type {};", self.ident),
239 ty::AssociatedKind::Existential => format!("existential type {};", self.ident),
240 ty::AssociatedKind::Const => {
241 format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id))
247 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
248 pub enum Visibility {
249 /// Visible everywhere (including in other crates).
251 /// Visible only in the given crate-local module.
253 /// Not visible anywhere in the local crate. This is the visibility of private external items.
257 pub trait DefIdTree: Copy {
258 fn parent(self, id: DefId) -> Option<DefId>;
260 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
261 if descendant.krate != ancestor.krate {
265 while descendant != ancestor {
266 match self.parent(descendant) {
267 Some(parent) => descendant = parent,
268 None => return false,
275 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
276 fn parent(self, id: DefId) -> Option<DefId> {
277 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
282 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt<'_, '_, '_>) -> Self {
283 match visibility.node {
284 hir::VisibilityKind::Public => Visibility::Public,
285 hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
286 hir::VisibilityKind::Restricted { ref path, .. } => match path.def {
287 // If there is no resolution, `resolve` will have already reported an error, so
288 // assume that the visibility is public to avoid reporting more privacy errors.
289 Def::Err => Visibility::Public,
290 def => Visibility::Restricted(def.def_id()),
292 hir::VisibilityKind::Inherited => {
293 Visibility::Restricted(tcx.hir.get_module_parent(id))
298 /// Returns `true` if an item with this visibility is accessible from the given block.
299 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
300 let restriction = match self {
301 // Public items are visible everywhere.
302 Visibility::Public => return true,
303 // Private items from other crates are visible nowhere.
304 Visibility::Invisible => return false,
305 // Restricted items are visible in an arbitrary local module.
306 Visibility::Restricted(other) if other.krate != module.krate => return false,
307 Visibility::Restricted(module) => module,
310 tree.is_descendant_of(module, restriction)
313 /// Returns `true` if this visibility is at least as accessible as the given visibility
314 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
315 let vis_restriction = match vis {
316 Visibility::Public => return self == Visibility::Public,
317 Visibility::Invisible => return true,
318 Visibility::Restricted(module) => module,
321 self.is_accessible_from(vis_restriction, tree)
324 // Returns `true` if this item is visible anywhere in the local crate.
325 pub fn is_visible_locally(self) -> bool {
327 Visibility::Public => true,
328 Visibility::Restricted(def_id) => def_id.is_local(),
329 Visibility::Invisible => false,
334 #[derive(Copy, Clone, PartialEq, Eq, RustcDecodable, RustcEncodable, Hash)]
336 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
337 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
338 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
339 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
342 /// The crate variances map is computed during typeck and contains the
343 /// variance of every item in the local crate. You should not use it
344 /// directly, because to do so will make your pass dependent on the
345 /// HIR of every item in the local crate. Instead, use
346 /// `tcx.variances_of()` to get the variance for a *particular*
348 pub struct CrateVariancesMap {
349 /// For each item with generics, maps to a vector of the variance
350 /// of its generics. If an item has no generics, it will have no
352 pub variances: FxHashMap<DefId, Lrc<Vec<ty::Variance>>>,
354 /// An empty vector, useful for cloning.
355 pub empty_variance: Lrc<Vec<ty::Variance>>,
359 /// `a.xform(b)` combines the variance of a context with the
360 /// variance of a type with the following meaning. If we are in a
361 /// context with variance `a`, and we encounter a type argument in
362 /// a position with variance `b`, then `a.xform(b)` is the new
363 /// variance with which the argument appears.
369 /// Here, the "ambient" variance starts as covariant. `*mut T` is
370 /// invariant with respect to `T`, so the variance in which the
371 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
372 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
373 /// respect to its type argument `T`, and hence the variance of
374 /// the `i32` here is `Invariant.xform(Covariant)`, which results
375 /// (again) in `Invariant`.
379 /// fn(*const Vec<i32>, *mut Vec<i32)
381 /// The ambient variance is covariant. A `fn` type is
382 /// contravariant with respect to its parameters, so the variance
383 /// within which both pointer types appear is
384 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
385 /// T` is covariant with respect to `T`, so the variance within
386 /// which the first `Vec<i32>` appears is
387 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
388 /// is true for its `i32` argument. In the `*mut T` case, the
389 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
390 /// and hence the outermost type is `Invariant` with respect to
391 /// `Vec<i32>` (and its `i32` argument).
393 /// Source: Figure 1 of "Taming the Wildcards:
394 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
395 pub fn xform(self, v: ty::Variance) -> ty::Variance {
397 // Figure 1, column 1.
398 (ty::Covariant, ty::Covariant) => ty::Covariant,
399 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
400 (ty::Covariant, ty::Invariant) => ty::Invariant,
401 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
403 // Figure 1, column 2.
404 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
405 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
406 (ty::Contravariant, ty::Invariant) => ty::Invariant,
407 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
409 // Figure 1, column 3.
410 (ty::Invariant, _) => ty::Invariant,
412 // Figure 1, column 4.
413 (ty::Bivariant, _) => ty::Bivariant,
418 // Contains information needed to resolve types and (in the future) look up
419 // the types of AST nodes.
420 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
421 pub struct CReaderCacheKey {
426 // Flags that we track on types. These flags are propagated upwards
427 // through the type during type construction, so that we can quickly
428 // check whether the type has various kinds of types in it without
429 // recursing over the type itself.
431 pub struct TypeFlags: u32 {
432 const HAS_PARAMS = 1 << 0;
433 const HAS_SELF = 1 << 1;
434 const HAS_TY_INFER = 1 << 2;
435 const HAS_RE_INFER = 1 << 3;
436 const HAS_RE_SKOL = 1 << 4;
438 /// Does this have any `ReEarlyBound` regions? Used to
439 /// determine whether substitition is required, since those
440 /// represent regions that are bound in a `ty::Generics` and
441 /// hence may be substituted.
442 const HAS_RE_EARLY_BOUND = 1 << 5;
444 /// Does this have any region that "appears free" in the type?
445 /// Basically anything but `ReLateBound` and `ReErased`.
446 const HAS_FREE_REGIONS = 1 << 6;
448 /// Is an error type reachable?
449 const HAS_TY_ERR = 1 << 7;
450 const HAS_PROJECTION = 1 << 8;
452 // FIXME: Rename this to the actual property since it's used for generators too
453 const HAS_TY_CLOSURE = 1 << 9;
455 // `true` if there are "names" of types and regions and so forth
456 // that are local to a particular fn
457 const HAS_FREE_LOCAL_NAMES = 1 << 10;
459 // Present if the type belongs in a local type context.
460 // Only set for Infer other than Fresh.
461 const KEEP_IN_LOCAL_TCX = 1 << 11;
463 // Is there a projection that does not involve a bound region?
464 // Currently we can't normalize projections w/ bound regions.
465 const HAS_NORMALIZABLE_PROJECTION = 1 << 12;
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 << 13;
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_RE_LATE_BOUND.bits;
494 pub struct TyS<'tcx> {
495 pub sty: TyKind<'tcx>,
496 pub flags: TypeFlags,
498 /// This is a kind of confusing thing: it stores the smallest
501 /// (a) the binder itself captures nothing but
502 /// (b) all the late-bound things within the type are captured
503 /// by some sub-binder.
505 /// So, for a type without any late-bound things, like `u32`, this
506 /// will be INNERMOST, because that is the innermost binder that
507 /// captures nothing. But for a type `&'D u32`, where `'D` is a
508 /// late-bound region with debruijn index D, this would be D+1 --
509 /// the binder itself does not capture D, but D is captured by an
512 /// We call this concept an "exclusive" binder D (because all
513 /// debruijn indices within the type are contained within `0..D`
515 outer_exclusive_binder: ty::DebruijnIndex,
518 // `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
519 #[cfg(target_arch = "x86_64")]
520 static_assert!(MEM_SIZE_OF_TY_S: ::std::mem::size_of::<TyS<'_>>() == 32);
522 impl<'tcx> Ord for TyS<'tcx> {
523 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
524 self.sty.cmp(&other.sty)
528 impl<'tcx> PartialOrd for TyS<'tcx> {
529 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
530 Some(self.sty.cmp(&other.sty))
534 impl<'tcx> PartialEq for TyS<'tcx> {
536 fn eq(&self, other: &TyS<'tcx>) -> bool {
540 impl<'tcx> Eq for TyS<'tcx> {}
542 impl<'tcx> Hash for TyS<'tcx> {
543 fn hash<H: Hasher>(&self, s: &mut H) {
544 (self as *const TyS<'_>).hash(s)
548 impl<'tcx> TyS<'tcx> {
549 pub fn is_primitive_ty(&self) -> bool {
556 TyKind::Infer(InferTy::IntVar(_)) |
557 TyKind::Infer(InferTy::FloatVar(_)) |
558 TyKind::Infer(InferTy::FreshIntTy(_)) |
559 TyKind::Infer(InferTy::FreshFloatTy(_)) => true,
560 TyKind::Ref(_, x, _) => x.is_primitive_ty(),
565 pub fn is_suggestable(&self) -> bool {
570 TyKind::Dynamic(..) |
571 TyKind::Closure(..) |
573 TyKind::Projection(..) => false,
579 impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for ty::TyS<'gcx> {
580 fn hash_stable<W: StableHasherResult>(&self,
581 hcx: &mut StableHashingContext<'a>,
582 hasher: &mut StableHasher<W>) {
586 // The other fields just provide fast access to information that is
587 // also contained in `sty`, so no need to hash them.
590 outer_exclusive_binder: _,
593 sty.hash_stable(hcx, hasher);
597 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
599 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
600 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
602 pub type CanonicalTy<'gcx> = Canonical<'gcx, Ty<'gcx>>;
605 /// A dummy type used to force List to by unsized without requiring fat pointers
606 type OpaqueListContents;
609 /// A wrapper for slices with the additional invariant
610 /// that the slice is interned and no other slice with
611 /// the same contents can exist in the same context.
612 /// This means we can use pointer for both
613 /// equality comparisons and hashing.
614 /// Note: `Slice` was already taken by the `Ty`.
619 opaque: OpaqueListContents,
622 unsafe impl<T: Sync> Sync for List<T> {}
624 impl<T: Copy> List<T> {
626 fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx List<T> {
627 assert!(!mem::needs_drop::<T>());
628 assert!(mem::size_of::<T>() != 0);
629 assert!(slice.len() != 0);
631 // Align up the size of the len (usize) field
632 let align = mem::align_of::<T>();
633 let align_mask = align - 1;
634 let offset = mem::size_of::<usize>();
635 let offset = (offset + align_mask) & !align_mask;
637 let size = offset + slice.len() * mem::size_of::<T>();
639 let mem = arena.alloc_raw(
641 cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
643 let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
645 result.len = slice.len();
647 // Write the elements
648 let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
649 arena_slice.copy_from_slice(slice);
656 impl<T: fmt::Debug> fmt::Debug for List<T> {
657 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
662 impl<T: Encodable> Encodable for List<T> {
664 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
669 impl<T> Ord for List<T> where T: Ord {
670 fn cmp(&self, other: &List<T>) -> Ordering {
671 if self == other { Ordering::Equal } else {
672 <[T] as Ord>::cmp(&**self, &**other)
677 impl<T> PartialOrd for List<T> where T: PartialOrd {
678 fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> {
679 if self == other { Some(Ordering::Equal) } else {
680 <[T] as PartialOrd>::partial_cmp(&**self, &**other)
685 impl<T: PartialEq> PartialEq for List<T> {
687 fn eq(&self, other: &List<T>) -> bool {
691 impl<T: Eq> Eq for List<T> {}
693 impl<T> Hash for List<T> {
695 fn hash<H: Hasher>(&self, s: &mut H) {
696 (self as *const List<T>).hash(s)
700 impl<T> Deref for List<T> {
703 fn deref(&self) -> &[T] {
705 slice::from_raw_parts(self.data.as_ptr(), self.len)
710 impl<'a, T> IntoIterator for &'a List<T> {
712 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
714 fn into_iter(self) -> Self::IntoIter {
719 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
723 pub fn empty<'a>() -> &'a List<T> {
724 #[repr(align(64), C)]
725 struct EmptySlice([u8; 64]);
726 static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
727 assert!(mem::align_of::<T>() <= 64);
729 &*(&EMPTY_SLICE as *const _ as *const List<T>)
734 /// Upvars do not get their own node-id. Instead, we use the pair of
735 /// the original var id (that is, the root variable that is referenced
736 /// by the upvar) and the id of the closure expression.
737 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
739 pub var_id: hir::HirId,
740 pub closure_expr_id: LocalDefId,
743 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
744 pub enum BorrowKind {
745 /// Data must be immutable and is aliasable.
748 /// Data must be immutable but not aliasable. This kind of borrow
749 /// cannot currently be expressed by the user and is used only in
750 /// implicit closure bindings. It is needed when the closure
751 /// is borrowing or mutating a mutable referent, e.g.:
753 /// let x: &mut isize = ...;
754 /// let y = || *x += 5;
756 /// If we were to try to translate this closure into a more explicit
757 /// form, we'd encounter an error with the code as written:
759 /// struct Env { x: & &mut isize }
760 /// let x: &mut isize = ...;
761 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
762 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
764 /// This is then illegal because you cannot mutate a `&mut` found
765 /// in an aliasable location. To solve, you'd have to translate with
766 /// an `&mut` borrow:
768 /// struct Env { x: & &mut isize }
769 /// let x: &mut isize = ...;
770 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
771 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
773 /// Now the assignment to `**env.x` is legal, but creating a
774 /// mutable pointer to `x` is not because `x` is not mutable. We
775 /// could fix this by declaring `x` as `let mut x`. This is ok in
776 /// user code, if awkward, but extra weird for closures, since the
777 /// borrow is hidden.
779 /// So we introduce a "unique imm" borrow -- the referent is
780 /// immutable, but not aliasable. This solves the problem. For
781 /// simplicity, we don't give users the way to express this
782 /// borrow, it's just used when translating closures.
785 /// Data is mutable and not aliasable.
789 /// Information describing the capture of an upvar. This is computed
790 /// during `typeck`, specifically by `regionck`.
791 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
792 pub enum UpvarCapture<'tcx> {
793 /// Upvar is captured by value. This is always true when the
794 /// closure is labeled `move`, but can also be true in other cases
795 /// depending on inference.
798 /// Upvar is captured by reference.
799 ByRef(UpvarBorrow<'tcx>),
802 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
803 pub struct UpvarBorrow<'tcx> {
804 /// The kind of borrow: by-ref upvars have access to shared
805 /// immutable borrows, which are not part of the normal language
807 pub kind: BorrowKind,
809 /// Region of the resulting reference.
810 pub region: ty::Region<'tcx>,
813 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
815 #[derive(Copy, Clone)]
816 pub struct ClosureUpvar<'tcx> {
822 #[derive(Clone, Copy, PartialEq, Eq)]
823 pub enum IntVarValue {
825 UintType(ast::UintTy),
828 #[derive(Clone, Copy, PartialEq, Eq)]
829 pub struct FloatVarValue(pub ast::FloatTy);
831 impl ty::EarlyBoundRegion {
832 pub fn to_bound_region(&self) -> ty::BoundRegion {
833 ty::BoundRegion::BrNamed(self.def_id, self.name)
836 /// Does this early bound region have a name? Early bound regions normally
837 /// always have names except when using anonymous lifetimes (`'_`).
838 pub fn has_name(&self) -> bool {
839 self.name != keywords::UnderscoreLifetime.name().as_interned_str()
843 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
844 pub enum GenericParamDefKind {
848 object_lifetime_default: ObjectLifetimeDefault,
849 synthetic: Option<hir::SyntheticTyParamKind>,
853 #[derive(Clone, RustcEncodable, RustcDecodable)]
854 pub struct GenericParamDef {
855 pub name: InternedString,
859 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
860 /// on generic parameter `'a`/`T`, asserts data behind the parameter
861 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
862 pub pure_wrt_drop: bool,
864 pub kind: GenericParamDefKind,
867 impl GenericParamDef {
868 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
869 if let GenericParamDefKind::Lifetime = self.kind {
870 ty::EarlyBoundRegion {
876 bug!("cannot convert a non-lifetime parameter def to an early bound region")
880 pub fn to_bound_region(&self) -> ty::BoundRegion {
881 if let GenericParamDefKind::Lifetime = self.kind {
882 self.to_early_bound_region_data().to_bound_region()
884 bug!("cannot convert a non-lifetime parameter def to an early bound region")
890 pub struct GenericParamCount {
891 pub lifetimes: usize,
895 /// Information about the formal type/lifetime parameters associated
896 /// with an item or method. Analogous to hir::Generics.
898 /// The ordering of parameters is the same as in Subst (excluding child generics):
899 /// Self (optionally), Lifetime params..., Type params...
900 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
901 pub struct Generics {
902 pub parent: Option<DefId>,
903 pub parent_count: usize,
904 pub params: Vec<GenericParamDef>,
906 /// Reverse map to the `index` field of each `GenericParamDef`
907 pub param_def_id_to_index: FxHashMap<DefId, u32>,
910 pub has_late_bound_regions: Option<Span>,
913 impl<'a, 'gcx, 'tcx> Generics {
914 pub fn count(&self) -> usize {
915 self.parent_count + self.params.len()
918 pub fn own_counts(&self) -> GenericParamCount {
919 // We could cache this as a property of `GenericParamCount`, but
920 // the aim is to refactor this away entirely eventually and the
921 // presence of this method will be a constant reminder.
922 let mut own_counts: GenericParamCount = Default::default();
924 for param in &self.params {
926 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
927 GenericParamDefKind::Type { .. } => own_counts.types += 1,
934 pub fn requires_monomorphization(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
935 for param in &self.params {
937 GenericParamDefKind::Type { .. } => return true,
938 GenericParamDefKind::Lifetime => {}
941 if let Some(parent_def_id) = self.parent {
942 let parent = tcx.generics_of(parent_def_id);
943 parent.requires_monomorphization(tcx)
949 pub fn region_param(&'tcx self,
950 param: &EarlyBoundRegion,
951 tcx: TyCtxt<'a, 'gcx, 'tcx>)
952 -> &'tcx GenericParamDef
954 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
955 let param = &self.params[index as usize];
957 ty::GenericParamDefKind::Lifetime => param,
958 _ => bug!("expected lifetime parameter, but found another generic parameter")
961 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
962 .region_param(param, tcx)
966 /// Returns the `GenericParamDef` associated with this `ParamTy`.
967 pub fn type_param(&'tcx self,
969 tcx: TyCtxt<'a, 'gcx, 'tcx>)
970 -> &'tcx GenericParamDef {
971 if let Some(index) = param.idx.checked_sub(self.parent_count as u32) {
972 let param = &self.params[index as usize];
974 ty::GenericParamDefKind::Type {..} => param,
975 _ => bug!("expected type parameter, but found another generic parameter")
978 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
979 .type_param(param, tcx)
984 /// Bounds on generics.
985 #[derive(Clone, Default)]
986 pub struct GenericPredicates<'tcx> {
987 pub parent: Option<DefId>,
988 pub predicates: Vec<(Predicate<'tcx>, Span)>,
991 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
992 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
994 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
995 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
996 -> InstantiatedPredicates<'tcx> {
997 let mut instantiated = InstantiatedPredicates::empty();
998 self.instantiate_into(tcx, &mut instantiated, substs);
1002 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
1003 -> InstantiatedPredicates<'tcx> {
1004 InstantiatedPredicates {
1005 predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
1009 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1010 instantiated: &mut InstantiatedPredicates<'tcx>,
1011 substs: &Substs<'tcx>) {
1012 if let Some(def_id) = self.parent {
1013 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
1015 instantiated.predicates.extend(
1016 self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)),
1020 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1021 -> InstantiatedPredicates<'tcx> {
1022 let mut instantiated = InstantiatedPredicates::empty();
1023 self.instantiate_identity_into(tcx, &mut instantiated);
1027 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1028 instantiated: &mut InstantiatedPredicates<'tcx>) {
1029 if let Some(def_id) = self.parent {
1030 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
1032 instantiated.predicates.extend(self.predicates.iter().map(|&(p, _)| p))
1035 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1036 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
1037 -> InstantiatedPredicates<'tcx>
1039 assert_eq!(self.parent, None);
1040 InstantiatedPredicates {
1041 predicates: self.predicates.iter().map(|(pred, _)| {
1042 pred.subst_supertrait(tcx, poly_trait_ref)
1048 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1049 pub enum Predicate<'tcx> {
1050 /// Corresponds to `where Foo: Bar<A,B,C>`. `Foo` here would be
1051 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1052 /// would be the type parameters.
1053 Trait(PolyTraitPredicate<'tcx>),
1056 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1059 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1061 /// where `<T as TraitRef>::Name == X`, approximately.
1062 /// See the `ProjectionPredicate` struct for details.
1063 Projection(PolyProjectionPredicate<'tcx>),
1065 /// no syntax: `T` well-formed
1066 WellFormed(Ty<'tcx>),
1068 /// trait must be object-safe
1071 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
1072 /// for some substitutions `...` and `T` being a closure type.
1073 /// Satisfied (or refuted) once we know the closure's kind.
1074 ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
1077 Subtype(PolySubtypePredicate<'tcx>),
1079 /// Constant initializer must evaluate successfully.
1080 ConstEvaluatable(DefId, &'tcx Substs<'tcx>),
1083 /// The crate outlives map is computed during typeck and contains the
1084 /// outlives of every item in the local crate. You should not use it
1085 /// directly, because to do so will make your pass dependent on the
1086 /// HIR of every item in the local crate. Instead, use
1087 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1089 pub struct CratePredicatesMap<'tcx> {
1090 /// For each struct with outlive bounds, maps to a vector of the
1091 /// predicate of its outlive bounds. If an item has no outlives
1092 /// bounds, it will have no entry.
1093 pub predicates: FxHashMap<DefId, Lrc<Vec<ty::Predicate<'tcx>>>>,
1095 /// An empty vector, useful for cloning.
1096 pub empty_predicate: Lrc<Vec<ty::Predicate<'tcx>>>,
1099 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1100 fn as_ref(&self) -> &Predicate<'tcx> {
1105 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
1106 /// Performs a substitution suitable for going from a
1107 /// poly-trait-ref to supertraits that must hold if that
1108 /// poly-trait-ref holds. This is slightly different from a normal
1109 /// substitution in terms of what happens with bound regions. See
1110 /// lengthy comment below for details.
1111 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1112 trait_ref: &ty::PolyTraitRef<'tcx>)
1113 -> ty::Predicate<'tcx>
1115 // The interaction between HRTB and supertraits is not entirely
1116 // obvious. Let me walk you (and myself) through an example.
1118 // Let's start with an easy case. Consider two traits:
1120 // trait Foo<'a>: Bar<'a,'a> { }
1121 // trait Bar<'b,'c> { }
1123 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
1124 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
1125 // knew that `Foo<'x>` (for any 'x) then we also know that
1126 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1127 // normal substitution.
1129 // In terms of why this is sound, the idea is that whenever there
1130 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1131 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1132 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1135 // Another example to be careful of is this:
1137 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
1138 // trait Bar1<'b,'c> { }
1140 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
1141 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
1142 // reason is similar to the previous example: any impl of
1143 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
1144 // basically we would want to collapse the bound lifetimes from
1145 // the input (`trait_ref`) and the supertraits.
1147 // To achieve this in practice is fairly straightforward. Let's
1148 // consider the more complicated scenario:
1150 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
1151 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
1152 // where both `'x` and `'b` would have a DB index of 1.
1153 // The substitution from the input trait-ref is therefore going to be
1154 // `'a => 'x` (where `'x` has a DB index of 1).
1155 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1156 // early-bound parameter and `'b' is a late-bound parameter with a
1158 // - If we replace `'a` with `'x` from the input, it too will have
1159 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1160 // just as we wanted.
1162 // There is only one catch. If we just apply the substitution `'a
1163 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1164 // adjust the DB index because we substituting into a binder (it
1165 // tries to be so smart...) resulting in `for<'x> for<'b>
1166 // Bar1<'x,'b>` (we have no syntax for this, so use your
1167 // imagination). Basically the 'x will have DB index of 2 and 'b
1168 // will have DB index of 1. Not quite what we want. So we apply
1169 // the substitution to the *contents* of the trait reference,
1170 // rather than the trait reference itself (put another way, the
1171 // substitution code expects equal binding levels in the values
1172 // from the substitution and the value being substituted into, and
1173 // this trick achieves that).
1175 let substs = &trait_ref.skip_binder().substs;
1177 Predicate::Trait(ref binder) =>
1178 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1179 Predicate::Subtype(ref binder) =>
1180 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1181 Predicate::RegionOutlives(ref binder) =>
1182 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1183 Predicate::TypeOutlives(ref binder) =>
1184 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1185 Predicate::Projection(ref binder) =>
1186 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1187 Predicate::WellFormed(data) =>
1188 Predicate::WellFormed(data.subst(tcx, substs)),
1189 Predicate::ObjectSafe(trait_def_id) =>
1190 Predicate::ObjectSafe(trait_def_id),
1191 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1192 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1193 Predicate::ConstEvaluatable(def_id, const_substs) =>
1194 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1199 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1200 pub struct TraitPredicate<'tcx> {
1201 pub trait_ref: TraitRef<'tcx>
1204 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1206 impl<'tcx> TraitPredicate<'tcx> {
1207 pub fn def_id(&self) -> DefId {
1208 self.trait_ref.def_id
1211 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
1212 self.trait_ref.input_types()
1215 pub fn self_ty(&self) -> Ty<'tcx> {
1216 self.trait_ref.self_ty()
1220 impl<'tcx> PolyTraitPredicate<'tcx> {
1221 pub fn def_id(&self) -> DefId {
1222 // ok to skip binder since trait def-id does not care about regions
1223 self.skip_binder().def_id()
1227 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
1228 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A: B`
1229 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1230 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>,
1232 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>,
1234 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1235 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1237 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1238 pub struct SubtypePredicate<'tcx> {
1239 pub a_is_expected: bool,
1243 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1245 /// This kind of predicate has no *direct* correspondent in the
1246 /// syntax, but it roughly corresponds to the syntactic forms:
1248 /// 1. `T: TraitRef<..., Item=Type>`
1249 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1251 /// In particular, form #1 is "desugared" to the combination of a
1252 /// normal trait predicate (`T: TraitRef<...>`) and one of these
1253 /// predicates. Form #2 is a broader form in that it also permits
1254 /// equality between arbitrary types. Processing an instance of
1255 /// Form #2 eventually yields one of these `ProjectionPredicate`
1256 /// instances to normalize the LHS.
1257 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1258 pub struct ProjectionPredicate<'tcx> {
1259 pub projection_ty: ProjectionTy<'tcx>,
1263 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1265 impl<'tcx> PolyProjectionPredicate<'tcx> {
1266 /// Returns the `DefId` of the associated item being projected.
1267 pub fn item_def_id(&self) -> DefId {
1268 self.skip_binder().projection_ty.item_def_id
1271 pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'_, '_, '_>) -> PolyTraitRef<'tcx> {
1272 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
1273 // `self.0.trait_ref` is permitted to have escaping regions.
1274 // This is because here `self` has a `Binder` and so does our
1275 // return value, so we are preserving the number of binding
1277 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1280 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1281 self.map_bound(|predicate| predicate.ty)
1284 /// The `DefId` of the `TraitItem` for the associated type.
1286 /// Note that this is not the `DefId` of the `TraitRef` containing this
1287 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
1288 pub fn projection_def_id(&self) -> DefId {
1289 // okay to skip binder since trait def-id does not care about regions
1290 self.skip_binder().projection_ty.item_def_id
1294 pub trait ToPolyTraitRef<'tcx> {
1295 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1298 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1299 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1300 ty::Binder::dummy(self.clone())
1304 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1305 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1306 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1310 pub trait ToPredicate<'tcx> {
1311 fn to_predicate(&self) -> Predicate<'tcx>;
1314 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1315 fn to_predicate(&self) -> Predicate<'tcx> {
1316 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1317 trait_ref: self.clone()
1322 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1323 fn to_predicate(&self) -> Predicate<'tcx> {
1324 ty::Predicate::Trait(self.to_poly_trait_predicate())
1328 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1329 fn to_predicate(&self) -> Predicate<'tcx> {
1330 Predicate::RegionOutlives(self.clone())
1334 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1335 fn to_predicate(&self) -> Predicate<'tcx> {
1336 Predicate::TypeOutlives(self.clone())
1340 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1341 fn to_predicate(&self) -> Predicate<'tcx> {
1342 Predicate::Projection(self.clone())
1346 impl<'tcx> Predicate<'tcx> {
1347 /// Iterates over the types in this predicate. Note that in all
1348 /// cases this is skipping over a binder, so late-bound regions
1349 /// with depth 0 are bound by the predicate.
1350 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1351 let vec: Vec<_> = match *self {
1352 ty::Predicate::Trait(ref data) => {
1353 data.skip_binder().input_types().collect()
1355 ty::Predicate::Subtype(binder) => {
1356 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1359 ty::Predicate::TypeOutlives(binder) => {
1360 vec![binder.skip_binder().0]
1362 ty::Predicate::RegionOutlives(..) => {
1365 ty::Predicate::Projection(ref data) => {
1366 let inner = data.skip_binder();
1367 inner.projection_ty.substs.types().chain(Some(inner.ty)).collect()
1369 ty::Predicate::WellFormed(data) => {
1372 ty::Predicate::ObjectSafe(_trait_def_id) => {
1375 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1376 closure_substs.substs.types().collect()
1378 ty::Predicate::ConstEvaluatable(_, substs) => {
1379 substs.types().collect()
1383 // FIXME: The only reason to collect into a vector here is that I was
1384 // too lazy to make the full (somewhat complicated) iterator
1385 // type that would be needed here. But I wanted this fn to
1386 // return an iterator conceptually, rather than a `Vec`, so as
1387 // to be closer to `Ty::walk`.
1391 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1393 Predicate::Trait(ref t) => {
1394 Some(t.to_poly_trait_ref())
1396 Predicate::Projection(..) |
1397 Predicate::Subtype(..) |
1398 Predicate::RegionOutlives(..) |
1399 Predicate::WellFormed(..) |
1400 Predicate::ObjectSafe(..) |
1401 Predicate::ClosureKind(..) |
1402 Predicate::TypeOutlives(..) |
1403 Predicate::ConstEvaluatable(..) => {
1409 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1411 Predicate::TypeOutlives(data) => {
1414 Predicate::Trait(..) |
1415 Predicate::Projection(..) |
1416 Predicate::Subtype(..) |
1417 Predicate::RegionOutlives(..) |
1418 Predicate::WellFormed(..) |
1419 Predicate::ObjectSafe(..) |
1420 Predicate::ClosureKind(..) |
1421 Predicate::ConstEvaluatable(..) => {
1428 /// Represents the bounds declared on a particular set of type
1429 /// parameters. Should eventually be generalized into a flag list of
1430 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1431 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1432 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1433 /// the `GenericPredicates` are expressed in terms of the bound type
1434 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1435 /// represented a set of bounds for some particular instantiation,
1436 /// meaning that the generic parameters have been substituted with
1441 /// struct Foo<T,U:Bar<T>> { ... }
1443 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1444 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1445 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1446 /// [usize:Bar<isize>]]`.
1448 pub struct InstantiatedPredicates<'tcx> {
1449 pub predicates: Vec<Predicate<'tcx>>,
1452 impl<'tcx> InstantiatedPredicates<'tcx> {
1453 pub fn empty() -> InstantiatedPredicates<'tcx> {
1454 InstantiatedPredicates { predicates: vec![] }
1457 pub fn is_empty(&self) -> bool {
1458 self.predicates.is_empty()
1462 /// "Universes" are used during type- and trait-checking in the
1463 /// presence of `for<..>` binders to control what sets of names are
1464 /// visible. Universes are arranged into a tree: the root universe
1465 /// contains names that are always visible. Each child then adds a new
1466 /// set of names that are visible, in addition to those of its parent.
1467 /// We say that the child universe "extends" the parent universe with
1470 /// To make this more concrete, consider this program:
1474 /// fn bar<T>(x: T) {
1475 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1479 /// The struct name `Foo` is in the root universe U0. But the type
1480 /// parameter `T`, introduced on `bar`, is in an extended universe U1
1481 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
1482 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
1483 /// region `'a` is in a universe U2 that extends U1, because we can
1484 /// name it inside the fn type but not outside.
1486 /// Universes are used to do type- and trait-checking around these
1487 /// "forall" binders (also called **universal quantification**). The
1488 /// idea is that when, in the body of `bar`, we refer to `T` as a
1489 /// type, we aren't referring to any type in particular, but rather a
1490 /// kind of "fresh" type that is distinct from all other types we have
1491 /// actually declared. This is called a **placeholder** type, and we
1492 /// use universes to talk about this. In other words, a type name in
1493 /// universe 0 always corresponds to some "ground" type that the user
1494 /// declared, but a type name in a non-zero universe is a placeholder
1495 /// type -- an idealized representative of "types in general" that we
1496 /// use for checking generic functions.
1498 pub struct UniverseIndex {
1499 DEBUG_FORMAT = "U{}",
1503 impl_stable_hash_for!(struct UniverseIndex { private });
1505 impl UniverseIndex {
1506 pub const ROOT: UniverseIndex = UniverseIndex::from_u32_const(0);
1508 /// Returns the "next" universe index in order -- this new index
1509 /// is considered to extend all previous universes. This
1510 /// corresponds to entering a `forall` quantifier. So, for
1511 /// example, suppose we have this type in universe `U`:
1514 /// for<'a> fn(&'a u32)
1517 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1518 /// new universe that extends `U` -- in this new universe, we can
1519 /// name the region `'a`, but that region was not nameable from
1520 /// `U` because it was not in scope there.
1521 pub fn next_universe(self) -> UniverseIndex {
1522 UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
1525 /// Returns `true` if `self` can name a name from `other` -- in other words,
1526 /// if the set of names in `self` is a superset of those in
1527 /// `other` (`self >= other`).
1528 pub fn can_name(self, other: UniverseIndex) -> bool {
1529 self.private >= other.private
1532 /// Returns `true` if `self` cannot name some names from `other` -- in other
1533 /// words, if the set of names in `self` is a strict subset of
1534 /// those in `other` (`self < other`).
1535 pub fn cannot_name(self, other: UniverseIndex) -> bool {
1536 self.private < other.private
1540 /// The "placeholder index" fully defines a placeholder region.
1541 /// Placeholder regions are identified by both a **universe** as well
1542 /// as a "bound-region" within that universe. The `bound_region` is
1543 /// basically a name -- distinct bound regions within the same
1544 /// universe are just two regions with an unknown relationship to one
1546 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
1547 pub struct Placeholder {
1548 pub universe: UniverseIndex,
1549 pub name: BoundRegion,
1552 impl_stable_hash_for!(struct Placeholder { universe, name });
1554 /// When type checking, we use the `ParamEnv` to track
1555 /// details about the set of where-clauses that are in scope at this
1556 /// particular point.
1557 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1558 pub struct ParamEnv<'tcx> {
1559 /// Obligations that the caller must satisfy. This is basically
1560 /// the set of bounds on the in-scope type parameters, translated
1561 /// into Obligations, and elaborated and normalized.
1562 pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1564 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1565 /// want `Reveal::All` -- note that this is always paired with an
1566 /// empty environment. To get that, use `ParamEnv::reveal()`.
1567 pub reveal: traits::Reveal,
1570 impl<'tcx> ParamEnv<'tcx> {
1571 /// Construct a trait environment suitable for contexts where
1572 /// there are no where clauses in scope. Hidden types (like `impl
1573 /// Trait`) are left hidden, so this is suitable for ordinary
1575 pub fn empty() -> Self {
1576 Self::new(List::empty(), Reveal::UserFacing)
1579 /// Construct a trait environment with no where clauses in scope
1580 /// where the values of all `impl Trait` and other hidden types
1581 /// are revealed. This is suitable for monomorphized, post-typeck
1582 /// environments like codegen or doing optimizations.
1584 /// N.B. If you want to have predicates in scope, use `ParamEnv::new`,
1585 /// or invoke `param_env.with_reveal_all()`.
1586 pub fn reveal_all() -> Self {
1587 Self::new(List::empty(), Reveal::All)
1590 /// Construct a trait environment with the given set of predicates.
1591 pub fn new(caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1594 ty::ParamEnv { caller_bounds, reveal }
1597 /// Returns a new parameter environment with the same clauses, but
1598 /// which "reveals" the true results of projections in all cases
1599 /// (even for associated types that are specializable). This is
1600 /// the desired behavior during codegen and certain other special
1601 /// contexts; normally though we want to use `Reveal::UserFacing`,
1602 /// which is the default.
1603 pub fn with_reveal_all(self) -> Self {
1604 ty::ParamEnv { reveal: Reveal::All, ..self }
1607 /// Returns this same environment but with no caller bounds.
1608 pub fn without_caller_bounds(self) -> Self {
1609 ty::ParamEnv { caller_bounds: List::empty(), ..self }
1612 /// Creates a suitable environment in which to perform trait
1613 /// queries on the given value. When type-checking, this is simply
1614 /// the pair of the environment plus value. But when reveal is set to
1615 /// All, then if `value` does not reference any type parameters, we will
1616 /// pair it with the empty environment. This improves caching and is generally
1619 /// NB: We preserve the environment when type-checking because it
1620 /// is possible for the user to have wacky where-clauses like
1621 /// `where Box<u32>: Copy`, which are clearly never
1622 /// satisfiable. We generally want to behave as if they were true,
1623 /// although the surrounding function is never reachable.
1624 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1626 Reveal::UserFacing => {
1635 || value.needs_infer()
1636 || value.has_param_types()
1637 || value.has_self_ty()
1645 param_env: self.without_caller_bounds(),
1654 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1655 pub struct ParamEnvAnd<'tcx, T> {
1656 pub param_env: ParamEnv<'tcx>,
1660 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1661 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1662 (self.param_env, self.value)
1666 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'gcx, T>
1667 where T: HashStable<StableHashingContext<'a>>
1669 fn hash_stable<W: StableHasherResult>(&self,
1670 hcx: &mut StableHashingContext<'a>,
1671 hasher: &mut StableHasher<W>) {
1677 param_env.hash_stable(hcx, hasher);
1678 value.hash_stable(hcx, hasher);
1682 #[derive(Copy, Clone, Debug)]
1683 pub struct Destructor {
1684 /// The def-id of the destructor method
1689 pub struct AdtFlags: u32 {
1690 const NO_ADT_FLAGS = 0;
1691 const IS_ENUM = 1 << 0;
1692 const IS_PHANTOM_DATA = 1 << 1;
1693 const IS_FUNDAMENTAL = 1 << 2;
1694 const IS_UNION = 1 << 3;
1695 const IS_BOX = 1 << 4;
1696 /// Indicates whether the type is an `Arc`.
1697 const IS_ARC = 1 << 5;
1698 /// Indicates whether the type is an `Rc`.
1699 const IS_RC = 1 << 6;
1700 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1701 /// (i.e., this flag is never set unless this ADT is an enum).
1702 const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 7;
1707 pub struct VariantFlags: u32 {
1708 const NO_VARIANT_FLAGS = 0;
1709 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1710 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1715 pub struct VariantDef {
1716 /// The variant's DefId. If this is a tuple-like struct,
1717 /// this is the DefId of the struct's ctor.
1719 pub name: Name, // struct's name if this is a struct
1720 pub discr: VariantDiscr,
1721 pub fields: Vec<FieldDef>,
1722 pub ctor_kind: CtorKind,
1723 flags: VariantFlags,
1726 impl<'a, 'gcx, 'tcx> VariantDef {
1727 /// Create a new `VariantDef`.
1729 /// - `did` is the DefId used for the variant - for tuple-structs, it is the constructor DefId,
1730 /// and for everything else, it is the variant DefId.
1731 /// - `attribute_def_id` is the DefId that has the variant's attributes.
1732 /// this is the struct DefId for structs, and the variant DefId for variants.
1734 /// Note that we *could* use the constructor DefId, because the constructor attributes
1735 /// redirect to the base attributes, but compiling a small crate requires
1736 /// loading the AdtDefs for all the structs in the universe (e.g. coherence for any
1737 /// built-in trait), and we do not want to load attributes twice.
1739 /// If someone speeds up attribute loading to not be a performance concern, they can
1740 /// remove this hack and use the constructor DefId everywhere.
1741 pub fn new(tcx: TyCtxt<'a, 'gcx, 'tcx>,
1744 discr: VariantDiscr,
1745 fields: Vec<FieldDef>,
1747 ctor_kind: CtorKind,
1748 attribute_def_id: DefId)
1751 debug!("VariantDef::new({:?}, {:?}, {:?}, {:?}, {:?}, {:?}, {:?})", did, name, discr,
1752 fields, adt_kind, ctor_kind, attribute_def_id);
1753 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1754 if adt_kind == AdtKind::Struct && tcx.has_attr(attribute_def_id, "non_exhaustive") {
1755 debug!("found non-exhaustive field list for {:?}", did);
1756 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1769 pub fn is_field_list_non_exhaustive(&self) -> bool {
1770 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1774 impl_stable_hash_for!(struct VariantDef {
1783 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1784 pub enum VariantDiscr {
1785 /// Explicit value for this variant, i.e. `X = 123`.
1786 /// The `DefId` corresponds to the embedded constant.
1789 /// The previous variant's discriminant plus one.
1790 /// For efficiency reasons, the distance from the
1791 /// last `Explicit` discriminant is being stored,
1792 /// or `0` for the first variant, if it has none.
1797 pub struct FieldDef {
1800 pub vis: Visibility,
1803 /// The definition of an abstract data type - a struct or enum.
1805 /// These are all interned (by intern_adt_def) into the adt_defs
1809 pub variants: IndexVec<self::layout::VariantIdx, VariantDef>,
1811 pub repr: ReprOptions,
1814 impl PartialOrd for AdtDef {
1815 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1816 Some(self.cmp(&other))
1820 /// There should be only one AdtDef for each `did`, therefore
1821 /// it is fine to implement `Ord` only based on `did`.
1822 impl Ord for AdtDef {
1823 fn cmp(&self, other: &AdtDef) -> Ordering {
1824 self.did.cmp(&other.did)
1828 impl PartialEq for AdtDef {
1829 // AdtDef are always interned and this is part of TyS equality
1831 fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) }
1834 impl Eq for AdtDef {}
1836 impl Hash for AdtDef {
1838 fn hash<H: Hasher>(&self, s: &mut H) {
1839 (self as *const AdtDef).hash(s)
1843 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1844 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1849 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1852 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1853 fn hash_stable<W: StableHasherResult>(&self,
1854 hcx: &mut StableHashingContext<'a>,
1855 hasher: &mut StableHasher<W>) {
1857 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> = Default::default();
1860 let hash: Fingerprint = CACHE.with(|cache| {
1861 let addr = self as *const AdtDef as usize;
1862 *cache.borrow_mut().entry(addr).or_insert_with(|| {
1870 let mut hasher = StableHasher::new();
1871 did.hash_stable(hcx, &mut hasher);
1872 variants.hash_stable(hcx, &mut hasher);
1873 flags.hash_stable(hcx, &mut hasher);
1874 repr.hash_stable(hcx, &mut hasher);
1880 hash.hash_stable(hcx, hasher);
1884 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
1885 pub enum AdtKind { Struct, Union, Enum }
1887 impl Into<DataTypeKind> for AdtKind {
1888 fn into(self) -> DataTypeKind {
1890 AdtKind::Struct => DataTypeKind::Struct,
1891 AdtKind::Union => DataTypeKind::Union,
1892 AdtKind::Enum => DataTypeKind::Enum,
1898 #[derive(RustcEncodable, RustcDecodable, Default)]
1899 pub struct ReprFlags: u8 {
1900 const IS_C = 1 << 0;
1901 const IS_SIMD = 1 << 1;
1902 const IS_TRANSPARENT = 1 << 2;
1903 // Internal only for now. If true, don't reorder fields.
1904 const IS_LINEAR = 1 << 3;
1906 // Any of these flags being set prevent field reordering optimisation.
1907 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1908 ReprFlags::IS_SIMD.bits |
1909 ReprFlags::IS_LINEAR.bits;
1913 impl_stable_hash_for!(struct ReprFlags {
1919 /// Represents the repr options provided by the user,
1920 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1921 pub struct ReprOptions {
1922 pub int: Option<attr::IntType>,
1925 pub flags: ReprFlags,
1928 impl_stable_hash_for!(struct ReprOptions {
1936 pub fn new(tcx: TyCtxt<'_, '_, '_>, did: DefId) -> ReprOptions {
1937 let mut flags = ReprFlags::empty();
1938 let mut size = None;
1939 let mut max_align = 0;
1940 let mut min_pack = 0;
1941 for attr in tcx.get_attrs(did).iter() {
1942 for r in attr::find_repr_attrs(&tcx.sess.parse_sess, attr) {
1943 flags.insert(match r {
1944 attr::ReprC => ReprFlags::IS_C,
1945 attr::ReprPacked(pack) => {
1946 min_pack = if min_pack > 0 {
1947 cmp::min(pack, min_pack)
1953 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
1954 attr::ReprSimd => ReprFlags::IS_SIMD,
1955 attr::ReprInt(i) => {
1959 attr::ReprAlign(align) => {
1960 max_align = cmp::max(align, max_align);
1967 // This is here instead of layout because the choice must make it into metadata.
1968 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1969 flags.insert(ReprFlags::IS_LINEAR);
1971 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
1975 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1977 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1979 pub fn packed(&self) -> bool { self.pack > 0 }
1981 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
1983 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1985 pub fn discr_type(&self) -> attr::IntType {
1986 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
1989 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
1990 /// layout" optimizations, such as representing `Foo<&T>` as a
1992 pub fn inhibit_enum_layout_opt(&self) -> bool {
1993 self.c() || self.int.is_some()
1996 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
1997 /// optimizations, such as with repr(C) or repr(packed(1)).
1998 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
1999 !(self.flags & ReprFlags::IS_UNOPTIMISABLE).is_empty() || (self.pack == 1)
2002 /// Returns true if this `#[repr()]` should inhibit union abi optimisations
2003 pub fn inhibit_union_abi_opt(&self) -> bool {
2009 impl<'a, 'gcx, 'tcx> AdtDef {
2010 fn new(tcx: TyCtxt<'_, '_, '_>,
2013 variants: IndexVec<VariantIdx, VariantDef>,
2014 repr: ReprOptions) -> Self {
2015 debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
2016 let mut flags = AdtFlags::NO_ADT_FLAGS;
2017 let attrs = tcx.get_attrs(did);
2018 if attr::contains_name(&attrs, "fundamental") {
2019 flags = flags | AdtFlags::IS_FUNDAMENTAL;
2021 if Some(did) == tcx.lang_items().phantom_data() {
2022 flags = flags | AdtFlags::IS_PHANTOM_DATA;
2024 if Some(did) == tcx.lang_items().owned_box() {
2025 flags = flags | AdtFlags::IS_BOX;
2027 if Some(did) == tcx.lang_items().arc() {
2028 flags = flags | AdtFlags::IS_ARC;
2030 if Some(did) == tcx.lang_items().rc() {
2031 flags = flags | AdtFlags::IS_RC;
2033 if kind == AdtKind::Enum && tcx.has_attr(did, "non_exhaustive") {
2034 debug!("found non-exhaustive variant list for {:?}", did);
2035 flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
2038 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
2039 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
2040 AdtKind::Struct => {}
2051 pub fn is_struct(&self) -> bool {
2052 !self.is_union() && !self.is_enum()
2056 pub fn is_union(&self) -> bool {
2057 self.flags.intersects(AdtFlags::IS_UNION)
2061 pub fn is_enum(&self) -> bool {
2062 self.flags.intersects(AdtFlags::IS_ENUM)
2066 pub fn is_variant_list_non_exhaustive(&self) -> bool {
2067 self.flags.intersects(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
2070 /// Returns the kind of the ADT - Struct or Enum.
2072 pub fn adt_kind(&self) -> AdtKind {
2075 } else if self.is_union() {
2082 pub fn descr(&self) -> &'static str {
2083 match self.adt_kind() {
2084 AdtKind::Struct => "struct",
2085 AdtKind::Union => "union",
2086 AdtKind::Enum => "enum",
2090 pub fn variant_descr(&self) -> &'static str {
2091 match self.adt_kind() {
2092 AdtKind::Struct => "struct",
2093 AdtKind::Union => "union",
2094 AdtKind::Enum => "variant",
2098 /// Returns whether this type is #[fundamental] for the purposes
2099 /// of coherence checking.
2101 pub fn is_fundamental(&self) -> bool {
2102 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
2105 /// Returns `true` if this is PhantomData<T>.
2107 pub fn is_phantom_data(&self) -> bool {
2108 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
2111 /// Returns `true` if this is `Arc<T>`.
2112 pub fn is_arc(&self) -> bool {
2113 self.flags.intersects(AdtFlags::IS_ARC)
2116 /// Returns `true` if this is `Rc<T>`.
2117 pub fn is_rc(&self) -> bool {
2118 self.flags.intersects(AdtFlags::IS_RC)
2121 /// Returns `true` if this is Box<T>.
2123 pub fn is_box(&self) -> bool {
2124 self.flags.intersects(AdtFlags::IS_BOX)
2127 /// Returns whether this type has a destructor.
2128 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
2129 self.destructor(tcx).is_some()
2132 /// Asserts this is a struct or union and returns its unique variant.
2133 pub fn non_enum_variant(&self) -> &VariantDef {
2134 assert!(self.is_struct() || self.is_union());
2135 &self.variants[VariantIdx::new(0)]
2139 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Lrc<GenericPredicates<'gcx>> {
2140 tcx.predicates_of(self.did)
2143 /// Returns an iterator over all fields contained
2146 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
2147 self.variants.iter().flat_map(|v| v.fields.iter())
2150 pub fn is_payloadfree(&self) -> bool {
2151 !self.variants.is_empty() &&
2152 self.variants.iter().all(|v| v.fields.is_empty())
2155 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
2158 .find(|v| v.did == vid)
2159 .expect("variant_with_id: unknown variant")
2162 pub fn variant_index_with_id(&self, vid: DefId) -> VariantIdx {
2165 .find(|(_, v)| v.did == vid)
2166 .expect("variant_index_with_id: unknown variant")
2170 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
2172 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
2173 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
2174 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) |
2175 Def::SelfCtor(..) => self.non_enum_variant(),
2176 _ => bug!("unexpected def {:?} in variant_of_def", def)
2181 pub fn eval_explicit_discr(
2183 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2185 ) -> Option<Discr<'tcx>> {
2186 let param_env = ParamEnv::empty();
2187 let repr_type = self.repr.discr_type();
2188 let substs = Substs::identity_for_item(tcx.global_tcx(), expr_did);
2189 let instance = ty::Instance::new(expr_did, substs);
2190 let cid = GlobalId {
2194 match tcx.const_eval(param_env.and(cid)) {
2196 // FIXME: Find the right type and use it instead of `val.ty` here
2197 if let Some(b) = val.assert_bits(tcx.global_tcx(), param_env.and(val.ty)) {
2198 trace!("discriminants: {} ({:?})", b, repr_type);
2204 info!("invalid enum discriminant: {:#?}", val);
2205 ::mir::interpret::struct_error(
2206 tcx.at(tcx.def_span(expr_did)),
2207 "constant evaluation of enum discriminant resulted in non-integer",
2212 Err(ErrorHandled::Reported) => {
2213 if !expr_did.is_local() {
2214 span_bug!(tcx.def_span(expr_did),
2215 "variant discriminant evaluation succeeded \
2216 in its crate but failed locally");
2220 Err(ErrorHandled::TooGeneric) => span_bug!(
2221 tcx.def_span(expr_did),
2222 "enum discriminant depends on generic arguments",
2228 pub fn discriminants(
2230 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2231 ) -> impl Iterator<Item=(VariantIdx, Discr<'tcx>)> + Captures<'gcx> + 'a {
2232 let repr_type = self.repr.discr_type();
2233 let initial = repr_type.initial_discriminant(tcx.global_tcx());
2234 let mut prev_discr = None::<Discr<'tcx>>;
2235 self.variants.iter_enumerated().map(move |(i, v)| {
2236 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
2237 if let VariantDiscr::Explicit(expr_did) = v.discr {
2238 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
2242 prev_discr = Some(discr);
2248 /// Compute the discriminant value used by a specific variant.
2249 /// Unlike `discriminants`, this is (amortized) constant-time,
2250 /// only doing at most one query for evaluating an explicit
2251 /// discriminant (the last one before the requested variant),
2252 /// assuming there are no constant-evaluation errors there.
2253 pub fn discriminant_for_variant(&self,
2254 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2255 variant_index: VariantIdx)
2257 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2258 let explicit_value = val
2259 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2260 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx.global_tcx()));
2261 explicit_value.checked_add(tcx, offset as u128).0
2264 /// Yields a DefId for the discriminant and an offset to add to it
2265 /// Alternatively, if there is no explicit discriminant, returns the
2266 /// inferred discriminant directly
2267 pub fn discriminant_def_for_variant(
2269 variant_index: VariantIdx,
2270 ) -> (Option<DefId>, u32) {
2271 let mut explicit_index = variant_index.as_u32();
2274 match self.variants[VariantIdx::from_u32(explicit_index)].discr {
2275 ty::VariantDiscr::Relative(0) => {
2279 ty::VariantDiscr::Relative(distance) => {
2280 explicit_index -= distance;
2282 ty::VariantDiscr::Explicit(did) => {
2283 expr_did = Some(did);
2288 (expr_did, variant_index.as_u32() - explicit_index)
2291 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
2292 tcx.adt_destructor(self.did)
2295 /// Returns a list of types such that `Self: Sized` if and only
2296 /// if that type is Sized, or `TyErr` if this type is recursive.
2298 /// Oddly enough, checking that the sized-constraint is Sized is
2299 /// actually more expressive than checking all members:
2300 /// the Sized trait is inductive, so an associated type that references
2301 /// Self would prevent its containing ADT from being Sized.
2303 /// Due to normalization being eager, this applies even if
2304 /// the associated type is behind a pointer, e.g. issue #31299.
2305 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
2306 match tcx.try_adt_sized_constraint(DUMMY_SP, self.did) {
2309 debug!("adt_sized_constraint: {:?} is recursive", self);
2310 // This should be reported as an error by `check_representable`.
2312 // Consider the type as Sized in the meanwhile to avoid
2313 // further errors. Delay our `bug` diagnostic here to get
2314 // emitted later as well in case we accidentally otherwise don't
2317 tcx.intern_type_list(&[tcx.types.err])
2322 fn sized_constraint_for_ty(&self,
2323 tcx: TyCtxt<'a, 'tcx, 'tcx>,
2326 let result = match ty.sty {
2327 Bool | Char | Int(..) | Uint(..) | Float(..) |
2328 RawPtr(..) | Ref(..) | FnDef(..) | FnPtr(_) |
2329 Array(..) | Closure(..) | Generator(..) | Never => {
2338 GeneratorWitness(..) => {
2339 // these are never sized - return the target type
2346 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
2350 Adt(adt, substs) => {
2352 let adt_tys = adt.sized_constraint(tcx);
2353 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
2356 .map(|ty| ty.subst(tcx, substs))
2357 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2361 Projection(..) | Opaque(..) => {
2362 // must calculate explicitly.
2363 // FIXME: consider special-casing always-Sized projections
2367 UnnormalizedProjection(..) => bug!("only used with chalk-engine"),
2370 // perf hack: if there is a `T: Sized` bound, then
2371 // we know that `T` is Sized and do not need to check
2374 let sized_trait = match tcx.lang_items().sized_trait() {
2376 _ => return vec![ty]
2378 let sized_predicate = Binder::dummy(TraitRef {
2379 def_id: sized_trait,
2380 substs: tcx.mk_substs_trait(ty, &[])
2382 let predicates = &tcx.predicates_of(self.did).predicates;
2383 if predicates.iter().any(|(p, _)| *p == sized_predicate) {
2392 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2396 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2401 impl<'a, 'gcx, 'tcx> FieldDef {
2402 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
2403 tcx.type_of(self.did).subst(tcx, subst)
2407 /// Represents the various closure traits in the Rust language. This
2408 /// will determine the type of the environment (`self`, in the
2409 /// desugaring) argument that the closure expects.
2411 /// You can get the environment type of a closure using
2412 /// `tcx.closure_env_ty()`.
2413 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
2414 pub enum ClosureKind {
2415 // Warning: Ordering is significant here! The ordering is chosen
2416 // because the trait Fn is a subtrait of FnMut and so in turn, and
2417 // hence we order it so that Fn < FnMut < FnOnce.
2423 impl<'a, 'tcx> ClosureKind {
2424 // This is the initial value used when doing upvar inference.
2425 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2427 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
2429 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
2430 ClosureKind::FnMut => {
2431 tcx.require_lang_item(FnMutTraitLangItem)
2433 ClosureKind::FnOnce => {
2434 tcx.require_lang_item(FnOnceTraitLangItem)
2439 /// Returns `true` if this a type that impls this closure kind
2440 /// must also implement `other`.
2441 pub fn extends(self, other: ty::ClosureKind) -> bool {
2442 match (self, other) {
2443 (ClosureKind::Fn, ClosureKind::Fn) => true,
2444 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2445 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2446 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2447 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2448 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2453 /// Returns the representative scalar type for this closure kind.
2454 /// See `TyS::to_opt_closure_kind` for more details.
2455 pub fn to_ty(self, tcx: TyCtxt<'_, '_, 'tcx>) -> Ty<'tcx> {
2457 ty::ClosureKind::Fn => tcx.types.i8,
2458 ty::ClosureKind::FnMut => tcx.types.i16,
2459 ty::ClosureKind::FnOnce => tcx.types.i32,
2464 impl<'tcx> TyS<'tcx> {
2465 /// Iterator that walks `self` and any types reachable from
2466 /// `self`, in depth-first order. Note that just walks the types
2467 /// that appear in `self`, it does not descend into the fields of
2468 /// structs or variants. For example:
2471 /// isize => { isize }
2472 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2473 /// [isize] => { [isize], isize }
2475 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2476 TypeWalker::new(self)
2479 /// Iterator that walks the immediate children of `self`. Hence
2480 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2481 /// (but not `i32`, like `walk`).
2482 pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
2483 walk::walk_shallow(self)
2486 /// Walks `ty` and any types appearing within `ty`, invoking the
2487 /// callback `f` on each type. If the callback returns false, then the
2488 /// children of the current type are ignored.
2490 /// Note: prefer `ty.walk()` where possible.
2491 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2492 where F: FnMut(Ty<'tcx>) -> bool
2494 let mut walker = self.walk();
2495 while let Some(ty) = walker.next() {
2497 walker.skip_current_subtree();
2504 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2506 hir::MutMutable => MutBorrow,
2507 hir::MutImmutable => ImmBorrow,
2511 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2512 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2513 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2515 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2517 MutBorrow => hir::MutMutable,
2518 ImmBorrow => hir::MutImmutable,
2520 // We have no type corresponding to a unique imm borrow, so
2521 // use `&mut`. It gives all the capabilities of an `&uniq`
2522 // and hence is a safe "over approximation".
2523 UniqueImmBorrow => hir::MutMutable,
2527 pub fn to_user_str(&self) -> &'static str {
2529 MutBorrow => "mutable",
2530 ImmBorrow => "immutable",
2531 UniqueImmBorrow => "uniquely immutable",
2536 #[derive(Debug, Clone)]
2537 pub enum Attributes<'gcx> {
2538 Owned(Lrc<[ast::Attribute]>),
2539 Borrowed(&'gcx [ast::Attribute])
2542 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2543 type Target = [ast::Attribute];
2545 fn deref(&self) -> &[ast::Attribute] {
2547 &Attributes::Owned(ref data) => &data,
2548 &Attributes::Borrowed(data) => data
2553 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2554 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2555 self.typeck_tables_of(self.hir.body_owner_def_id(body))
2558 /// Returns an iterator of the def-ids for all body-owners in this
2559 /// crate. If you would prefer to iterate over the bodies
2560 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
2563 ) -> impl Iterator<Item = DefId> + Captures<'tcx> + Captures<'gcx> + 'a {
2567 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
2570 pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
2571 par_iter(&self.hir.krate().body_ids).for_each(|&body_id| {
2572 f(self.hir.body_owner_def_id(body_id))
2576 pub fn expr_span(self, id: NodeId) -> Span {
2577 match self.hir.find(id) {
2578 Some(Node::Expr(e)) => {
2582 bug!("Node id {} is not an expr: {:?}", id, f);
2585 bug!("Node id {} is not present in the node map", id);
2590 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2591 self.associated_items(id)
2592 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2596 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2597 self.associated_items(did).any(|item| {
2598 item.relevant_for_never()
2602 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2603 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2604 match self.hir.get(node_id) {
2605 Node::TraitItem(_) | Node::ImplItem(_) => true,
2609 match self.describe_def(def_id).expect("no def for def-id") {
2610 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2615 if is_associated_item {
2616 Some(self.associated_item(def_id))
2622 fn associated_item_from_trait_item_ref(self,
2623 parent_def_id: DefId,
2624 parent_vis: &hir::Visibility,
2625 trait_item_ref: &hir::TraitItemRef)
2627 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2628 let (kind, has_self) = match trait_item_ref.kind {
2629 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2630 hir::AssociatedItemKind::Method { has_self } => {
2631 (ty::AssociatedKind::Method, has_self)
2633 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2634 hir::AssociatedItemKind::Existential => bug!("only impls can have existentials"),
2638 ident: trait_item_ref.ident,
2640 // Visibility of trait items is inherited from their traits.
2641 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2642 defaultness: trait_item_ref.defaultness,
2644 container: TraitContainer(parent_def_id),
2645 method_has_self_argument: has_self
2649 fn associated_item_from_impl_item_ref(self,
2650 parent_def_id: DefId,
2651 impl_item_ref: &hir::ImplItemRef)
2653 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2654 let (kind, has_self) = match impl_item_ref.kind {
2655 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2656 hir::AssociatedItemKind::Method { has_self } => {
2657 (ty::AssociatedKind::Method, has_self)
2659 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2660 hir::AssociatedItemKind::Existential => (ty::AssociatedKind::Existential, false),
2664 ident: impl_item_ref.ident,
2666 // Visibility of trait impl items doesn't matter.
2667 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2668 defaultness: impl_item_ref.defaultness,
2670 container: ImplContainer(parent_def_id),
2671 method_has_self_argument: has_self
2675 pub fn field_index(self, node_id: NodeId, tables: &TypeckTables<'_>) -> usize {
2676 let hir_id = self.hir.node_to_hir_id(node_id);
2677 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2680 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2681 variant.fields.iter().position(|field| {
2682 self.adjust_ident(ident, variant.did, DUMMY_NODE_ID).0 == field.ident.modern()
2686 pub fn associated_items(
2689 ) -> AssociatedItemsIterator<'a, 'gcx, 'tcx> {
2690 // Ideally, we would use `-> impl Iterator` here, but it falls
2691 // afoul of the conservative "capture [restrictions]" we put
2692 // in place, so we use a hand-written iterator.
2694 // [restrictions]: https://github.com/rust-lang/rust/issues/34511#issuecomment-373423999
2695 AssociatedItemsIterator {
2697 def_ids: self.associated_item_def_ids(def_id),
2702 /// Returns `true` if the impls are the same polarity and the trait either
2703 /// has no items or is annotated #[marker] and prevents item overrides.
2704 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2705 if self.features().overlapping_marker_traits {
2706 let trait1_is_empty = self.impl_trait_ref(def_id1)
2707 .map_or(false, |trait_ref| {
2708 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2710 let trait2_is_empty = self.impl_trait_ref(def_id2)
2711 .map_or(false, |trait_ref| {
2712 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2714 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2717 } else if self.features().marker_trait_attr {
2718 let is_marker_impl = |def_id: DefId| -> bool {
2719 let trait_ref = self.impl_trait_ref(def_id);
2720 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2722 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2723 && is_marker_impl(def_id1)
2724 && is_marker_impl(def_id2)
2730 // Returns `ty::VariantDef` if `def` refers to a struct,
2731 // or variant or their constructors, panics otherwise.
2732 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2734 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2735 let enum_did = self.parent_def_id(did).unwrap();
2736 self.adt_def(enum_did).variant_with_id(did)
2738 Def::Struct(did) | Def::Union(did) => {
2739 self.adt_def(did).non_enum_variant()
2741 Def::StructCtor(ctor_did, ..) => {
2742 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2743 self.adt_def(did).non_enum_variant()
2745 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2749 /// Given a `VariantDef`, returns the def-id of the `AdtDef` of which it is a part.
2750 pub fn adt_def_id_of_variant(self, variant_def: &'tcx VariantDef) -> DefId {
2751 let def_key = self.def_key(variant_def.did);
2752 match def_key.disambiguated_data.data {
2753 // for enum variants and tuple structs, the def-id of the ADT itself
2754 // is the *parent* of the variant
2755 DefPathData::EnumVariant(..) | DefPathData::StructCtor =>
2756 DefId { krate: variant_def.did.krate, index: def_key.parent.unwrap() },
2758 // otherwise, for structs and unions, they share a def-id
2759 _ => variant_def.did,
2763 pub fn item_name(self, id: DefId) -> InternedString {
2764 if id.index == CRATE_DEF_INDEX {
2765 self.original_crate_name(id.krate).as_interned_str()
2767 let def_key = self.def_key(id);
2768 // The name of a StructCtor is that of its struct parent.
2769 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2770 self.item_name(DefId {
2772 index: def_key.parent.unwrap()
2775 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2776 bug!("item_name: no name for {:?}", self.def_path(id));
2782 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2783 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2787 ty::InstanceDef::Item(did) => {
2788 self.optimized_mir(did)
2790 ty::InstanceDef::VtableShim(..) |
2791 ty::InstanceDef::Intrinsic(..) |
2792 ty::InstanceDef::FnPtrShim(..) |
2793 ty::InstanceDef::Virtual(..) |
2794 ty::InstanceDef::ClosureOnceShim { .. } |
2795 ty::InstanceDef::DropGlue(..) |
2796 ty::InstanceDef::CloneShim(..) => {
2797 self.mir_shims(instance)
2802 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2803 /// Returns None if there is no MIR for the DefId
2804 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2805 if self.is_mir_available(did) {
2806 Some(self.optimized_mir(did))
2812 /// Get the attributes of a definition.
2813 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2814 if let Some(id) = self.hir.as_local_node_id(did) {
2815 Attributes::Borrowed(self.hir.attrs(id))
2817 Attributes::Owned(self.item_attrs(did))
2821 /// Determine whether an item is annotated with an attribute.
2822 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2823 attr::contains_name(&self.get_attrs(did), attr)
2826 /// Returns `true` if this is an `auto trait`.
2827 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
2828 self.trait_def(trait_def_id).has_auto_impl
2831 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
2832 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
2835 /// Given the def-id of an impl, return the def_id of the trait it implements.
2836 /// If it implements no trait, return `None`.
2837 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2838 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2841 /// If the given defid describes a method belonging to an impl, return the
2842 /// def-id of the impl that the method belongs to. Otherwise, return `None`.
2843 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2844 let item = if def_id.krate != LOCAL_CRATE {
2845 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2846 Some(self.associated_item(def_id))
2851 self.opt_associated_item(def_id)
2854 item.and_then(|trait_item|
2855 match trait_item.container {
2856 TraitContainer(_) => None,
2857 ImplContainer(def_id) => Some(def_id),
2862 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2863 /// with the name of the crate containing the impl.
2864 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2865 if impl_did.is_local() {
2866 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2867 Ok(self.hir.span(node_id))
2869 Err(self.crate_name(impl_did.krate))
2873 // Hygienically compare a use-site name (`use_name`) for a field or an associated item with its
2874 // supposed definition name (`def_name`). The method also needs `DefId` of the supposed
2875 // definition's parent/scope to perform comparison.
2876 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
2877 self.adjust_ident(use_name, def_parent_def_id, DUMMY_NODE_ID).0 == def_name.modern()
2880 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
2881 ident = ident.modern();
2882 let target_expansion = match scope.krate {
2883 LOCAL_CRATE => self.hir.definitions().expansion_that_defined(scope.index),
2886 let scope = match ident.span.adjust(target_expansion) {
2887 Some(actual_expansion) =>
2888 self.hir.definitions().parent_module_of_macro_def(actual_expansion),
2889 None if block == DUMMY_NODE_ID => DefId::local(CRATE_DEF_INDEX), // Dummy DefId
2890 None => self.hir.get_module_parent(block),
2896 pub struct AssociatedItemsIterator<'a, 'gcx: 'tcx, 'tcx: 'a> {
2897 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2898 def_ids: Lrc<Vec<DefId>>,
2902 impl Iterator for AssociatedItemsIterator<'_, '_, '_> {
2903 type Item = AssociatedItem;
2905 fn next(&mut self) -> Option<AssociatedItem> {
2906 let def_id = self.def_ids.get(self.next_index)?;
2907 self.next_index += 1;
2908 Some(self.tcx.associated_item(*def_id))
2912 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2913 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2914 F: FnOnce(&[hir::Freevar]) -> T,
2916 let def_id = self.hir.local_def_id(fid);
2917 match self.freevars(def_id) {
2924 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> AssociatedItem {
2925 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2926 let parent_id = tcx.hir.get_parent(id);
2927 let parent_def_id = tcx.hir.local_def_id(parent_id);
2928 let parent_item = tcx.hir.expect_item(parent_id);
2929 match parent_item.node {
2930 hir::ItemKind::Impl(.., ref impl_item_refs) => {
2931 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2932 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2934 debug_assert_eq!(assoc_item.def_id, def_id);
2939 hir::ItemKind::Trait(.., ref trait_item_refs) => {
2940 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2941 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2944 debug_assert_eq!(assoc_item.def_id, def_id);
2952 span_bug!(parent_item.span,
2953 "unexpected parent of trait or impl item or item not found: {:?}",
2957 /// Calculates the Sized-constraint.
2959 /// In fact, there are only a few options for the types in the constraint:
2960 /// - an obviously-unsized type
2961 /// - a type parameter or projection whose Sizedness can't be known
2962 /// - a tuple of type parameters or projections, if there are multiple
2964 /// - a Error, if a type contained itself. The representability
2965 /// check should catch this case.
2966 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2968 -> &'tcx [Ty<'tcx>] {
2969 let def = tcx.adt_def(def_id);
2971 let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| {
2974 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2977 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2982 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2984 -> Lrc<Vec<DefId>> {
2985 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2986 let item = tcx.hir.expect_item(id);
2987 let vec: Vec<_> = match item.node {
2988 hir::ItemKind::Trait(.., ref trait_item_refs) => {
2989 trait_item_refs.iter()
2990 .map(|trait_item_ref| trait_item_ref.id)
2991 .map(|id| tcx.hir.local_def_id(id.node_id))
2994 hir::ItemKind::Impl(.., ref impl_item_refs) => {
2995 impl_item_refs.iter()
2996 .map(|impl_item_ref| impl_item_ref.id)
2997 .map(|id| tcx.hir.local_def_id(id.node_id))
3000 hir::ItemKind::TraitAlias(..) => vec![],
3001 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
3006 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
3007 tcx.hir.span_if_local(def_id).unwrap()
3010 /// If the given def ID describes an item belonging to a trait,
3011 /// return the ID of the trait that the trait item belongs to.
3012 /// Otherwise, return `None`.
3013 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
3014 tcx.opt_associated_item(def_id)
3015 .and_then(|associated_item| {
3016 match associated_item.container {
3017 TraitContainer(def_id) => Some(def_id),
3018 ImplContainer(_) => None
3023 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
3024 pub fn is_impl_trait_defn(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> Option<DefId> {
3025 if let Some(node_id) = tcx.hir.as_local_node_id(def_id) {
3026 if let Node::Item(item) = tcx.hir.get(node_id) {
3027 if let hir::ItemKind::Existential(ref exist_ty) = item.node {
3028 return exist_ty.impl_trait_fn;
3035 /// Returns `true` if `def_id` is a trait alias.
3036 pub fn is_trait_alias(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> bool {
3037 if let Some(node_id) = tcx.hir.as_local_node_id(def_id) {
3038 if let Node::Item(item) = tcx.hir.get(node_id) {
3039 if let hir::ItemKind::TraitAlias(..) = item.node {
3047 /// See `ParamEnv` struct definition for details.
3048 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3052 // The param_env of an impl Trait type is its defining function's param_env
3053 if let Some(parent) = is_impl_trait_defn(tcx, def_id) {
3054 return param_env(tcx, parent);
3056 // Compute the bounds on Self and the type parameters.
3058 let InstantiatedPredicates { predicates } =
3059 tcx.predicates_of(def_id).instantiate_identity(tcx);
3061 // Finally, we have to normalize the bounds in the environment, in
3062 // case they contain any associated type projections. This process
3063 // can yield errors if the put in illegal associated types, like
3064 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
3065 // report these errors right here; this doesn't actually feel
3066 // right to me, because constructing the environment feels like a
3067 // kind of a "idempotent" action, but I'm not sure where would be
3068 // a better place. In practice, we construct environments for
3069 // every fn once during type checking, and we'll abort if there
3070 // are any errors at that point, so after type checking you can be
3071 // sure that this will succeed without errors anyway.
3073 let unnormalized_env = ty::ParamEnv::new(tcx.intern_predicates(&predicates),
3074 traits::Reveal::UserFacing);
3076 let body_id = tcx.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
3077 tcx.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_id)
3079 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
3080 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
3083 fn crate_disambiguator<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3084 crate_num: CrateNum) -> CrateDisambiguator {
3085 assert_eq!(crate_num, LOCAL_CRATE);
3086 tcx.sess.local_crate_disambiguator()
3089 fn original_crate_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3090 crate_num: CrateNum) -> Symbol {
3091 assert_eq!(crate_num, LOCAL_CRATE);
3092 tcx.crate_name.clone()
3095 fn crate_hash<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3096 crate_num: CrateNum)
3098 assert_eq!(crate_num, LOCAL_CRATE);
3102 fn instance_def_size_estimate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3103 instance_def: InstanceDef<'tcx>)
3105 match instance_def {
3106 InstanceDef::Item(..) |
3107 InstanceDef::DropGlue(..) => {
3108 let mir = tcx.instance_mir(instance_def);
3109 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
3111 // Estimate the size of other compiler-generated shims to be 1.
3116 pub fn provide(providers: &mut ty::query::Providers<'_>) {
3117 context::provide(providers);
3118 erase_regions::provide(providers);
3119 layout::provide(providers);
3120 util::provide(providers);
3121 constness::provide(providers);
3122 *providers = ty::query::Providers {
3124 associated_item_def_ids,
3125 adt_sized_constraint,
3129 crate_disambiguator,
3130 original_crate_name,
3132 trait_impls_of: trait_def::trait_impls_of_provider,
3133 instance_def_size_estimate,
3138 /// A map for the local crate mapping each type to a vector of its
3139 /// inherent impls. This is not meant to be used outside of coherence;
3140 /// rather, you should request the vector for a specific type via
3141 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
3142 /// (constructing this map requires touching the entire crate).
3143 #[derive(Clone, Debug)]
3144 pub struct CrateInherentImpls {
3145 pub inherent_impls: DefIdMap<Lrc<Vec<DefId>>>,
3148 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
3149 pub struct SymbolName {
3150 // FIXME: we don't rely on interning or equality here - better have
3151 // this be a `&'tcx str`.
3152 pub name: InternedString
3155 impl_stable_hash_for!(struct self::SymbolName {
3160 pub fn new(name: &str) -> SymbolName {
3162 name: Symbol::intern(name).as_interned_str()
3166 pub fn as_str(&self) -> LocalInternedString {
3171 impl fmt::Display for SymbolName {
3172 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3173 fmt::Display::fmt(&self.name, fmt)
3177 impl fmt::Debug for SymbolName {
3178 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3179 fmt::Display::fmt(&self.name, fmt)