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};
18 use hir::def::{Def, CtorKind, ExportMap};
19 use hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
20 use hir::map::DefPathData;
23 use ich::StableHashingContext;
24 use infer::canonical::Canonical;
25 use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
26 use middle::privacy::AccessLevels;
27 use middle::resolve_lifetime::ObjectLifetimeDefault;
29 use mir::interpret::GlobalId;
30 use mir::GeneratorLayout;
31 use session::CrateDisambiguator;
32 use traits::{self, Reveal};
34 use ty::subst::{Subst, Substs};
35 use ty::util::{IntTypeExt, Discr};
36 use ty::walk::TypeWalker;
37 use util::captures::Captures;
38 use util::nodemap::{NodeSet, DefIdMap, FxHashMap};
39 use arena::SyncDroplessArena;
41 use serialize::{self, Encodable, Encoder};
42 use std::cell::RefCell;
43 use std::cmp::{self, Ordering};
45 use std::hash::{Hash, Hasher};
47 use rustc_data_structures::sync::{self, Lrc, ParallelIterator, par_iter};
49 use std::vec::IntoIter;
51 use syntax::ast::{self, DUMMY_NODE_ID, Name, Ident, NodeId};
53 use syntax::ext::hygiene::Mark;
54 use syntax::symbol::{Symbol, LocalInternedString, InternedString};
55 use syntax_pos::{DUMMY_SP, Span};
57 use rustc_data_structures::accumulate_vec::IntoIter as AccIntoIter;
58 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
63 pub use self::sty::{Binder, CanonicalVar, DebruijnIndex, INNERMOST};
64 pub use self::sty::{FnSig, GenSig, PolyFnSig, PolyGenSig};
65 pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
66 pub use self::sty::{ClosureSubsts, GeneratorSubsts, UpvarSubsts, TypeAndMut};
67 pub use self::sty::{TraitRef, TypeVariants, PolyTraitRef};
68 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
69 pub use self::sty::{ExistentialProjection, PolyExistentialProjection, Const};
70 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
71 pub use self::sty::RegionKind;
72 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid};
73 pub use self::sty::BoundRegion::*;
74 pub use self::sty::InferTy::*;
75 pub use self::sty::RegionKind::*;
76 pub use self::sty::TypeVariants::*;
78 pub use self::binding::BindingMode;
79 pub use self::binding::BindingMode::*;
81 pub use self::context::{TyCtxt, GlobalArenas, AllArenas, tls, keep_local};
82 pub use self::context::{Lift, TypeckTables};
84 pub use self::instance::{Instance, InstanceDef};
86 pub use self::trait_def::TraitDef;
88 pub use self::query::queries;
99 pub mod inhabitedness;
116 mod structural_impls;
121 /// The complete set of all analyses described in this module. This is
122 /// produced by the driver and fed to codegen and later passes.
124 /// NB: These contents are being migrated into queries using the
125 /// *on-demand* infrastructure.
127 pub struct CrateAnalysis {
128 pub access_levels: Lrc<AccessLevels>,
130 pub glob_map: Option<hir::GlobMap>,
134 pub struct Resolutions {
135 pub freevars: FreevarMap,
136 pub trait_map: TraitMap,
137 pub maybe_unused_trait_imports: NodeSet,
138 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
139 pub export_map: ExportMap,
142 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
143 pub enum AssociatedItemContainer {
144 TraitContainer(DefId),
145 ImplContainer(DefId),
148 impl AssociatedItemContainer {
149 /// Asserts that this is the def-id of an associated item declared
150 /// in a trait, and returns the trait def-id.
151 pub fn assert_trait(&self) -> DefId {
153 TraitContainer(id) => id,
154 _ => bug!("associated item has wrong container type: {:?}", self)
158 pub fn id(&self) -> DefId {
160 TraitContainer(id) => id,
161 ImplContainer(id) => id,
166 /// The "header" of an impl is everything outside the body: a Self type, a trait
167 /// ref (in the case of a trait impl), and a set of predicates (from the
168 /// bounds/where clauses).
169 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
170 pub struct ImplHeader<'tcx> {
171 pub impl_def_id: DefId,
172 pub self_ty: Ty<'tcx>,
173 pub trait_ref: Option<TraitRef<'tcx>>,
174 pub predicates: Vec<Predicate<'tcx>>,
177 #[derive(Copy, Clone, Debug, PartialEq)]
178 pub struct AssociatedItem {
181 pub kind: AssociatedKind,
183 pub defaultness: hir::Defaultness,
184 pub container: AssociatedItemContainer,
186 /// Whether this is a method with an explicit self
187 /// as its first argument, allowing method calls.
188 pub method_has_self_argument: bool,
191 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash, RustcEncodable, RustcDecodable)]
192 pub enum AssociatedKind {
199 impl AssociatedItem {
200 pub fn def(&self) -> Def {
202 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
203 AssociatedKind::Method => Def::Method(self.def_id),
204 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
205 AssociatedKind::Existential => Def::AssociatedExistential(self.def_id),
209 /// Tests whether the associated item admits a non-trivial implementation
211 pub fn relevant_for_never<'tcx>(&self) -> bool {
213 AssociatedKind::Existential |
214 AssociatedKind::Const |
215 AssociatedKind::Type => true,
216 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
217 AssociatedKind::Method => !self.method_has_self_argument,
221 pub fn signature<'a, 'tcx>(&self, tcx: &TyCtxt<'a, 'tcx, 'tcx>) -> String {
223 ty::AssociatedKind::Method => {
224 // We skip the binder here because the binder would deanonymize all
225 // late-bound regions, and we don't want method signatures to show up
226 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
227 // regions just fine, showing `fn(&MyType)`.
228 format!("{}", tcx.fn_sig(self.def_id).skip_binder())
230 ty::AssociatedKind::Type => format!("type {};", self.ident),
231 ty::AssociatedKind::Existential => format!("existential type {};", self.ident),
232 ty::AssociatedKind::Const => {
233 format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id))
239 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
240 pub enum Visibility {
241 /// Visible everywhere (including in other crates).
243 /// Visible only in the given crate-local module.
245 /// Not visible anywhere in the local crate. This is the visibility of private external items.
249 pub trait DefIdTree: Copy {
250 fn parent(self, id: DefId) -> Option<DefId>;
252 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
253 if descendant.krate != ancestor.krate {
257 while descendant != ancestor {
258 match self.parent(descendant) {
259 Some(parent) => descendant = parent,
260 None => return false,
267 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
268 fn parent(self, id: DefId) -> Option<DefId> {
269 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
274 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt) -> Self {
275 match visibility.node {
276 hir::VisibilityKind::Public => Visibility::Public,
277 hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
278 hir::VisibilityKind::Restricted { ref path, .. } => match path.def {
279 // If there is no resolution, `resolve` will have already reported an error, so
280 // assume that the visibility is public to avoid reporting more privacy errors.
281 Def::Err => Visibility::Public,
282 def => Visibility::Restricted(def.def_id()),
284 hir::VisibilityKind::Inherited => {
285 Visibility::Restricted(tcx.hir.get_module_parent(id))
290 /// Returns true if an item with this visibility is accessible from the given block.
291 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
292 let restriction = match self {
293 // Public items are visible everywhere.
294 Visibility::Public => return true,
295 // Private items from other crates are visible nowhere.
296 Visibility::Invisible => return false,
297 // Restricted items are visible in an arbitrary local module.
298 Visibility::Restricted(other) if other.krate != module.krate => return false,
299 Visibility::Restricted(module) => module,
302 tree.is_descendant_of(module, restriction)
305 /// Returns true if this visibility is at least as accessible as the given visibility
306 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
307 let vis_restriction = match vis {
308 Visibility::Public => return self == Visibility::Public,
309 Visibility::Invisible => return true,
310 Visibility::Restricted(module) => module,
313 self.is_accessible_from(vis_restriction, tree)
316 // Returns true if this item is visible anywhere in the local crate.
317 pub fn is_visible_locally(self) -> bool {
319 Visibility::Public => true,
320 Visibility::Restricted(def_id) => def_id.is_local(),
321 Visibility::Invisible => false,
326 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
328 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
329 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
330 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
331 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
334 /// The crate variances map is computed during typeck and contains the
335 /// variance of every item in the local crate. You should not use it
336 /// directly, because to do so will make your pass dependent on the
337 /// HIR of every item in the local crate. Instead, use
338 /// `tcx.variances_of()` to get the variance for a *particular*
340 pub struct CrateVariancesMap {
341 /// For each item with generics, maps to a vector of the variance
342 /// of its generics. If an item has no generics, it will have no
344 pub variances: FxHashMap<DefId, Lrc<Vec<ty::Variance>>>,
346 /// An empty vector, useful for cloning.
347 pub empty_variance: Lrc<Vec<ty::Variance>>,
351 /// `a.xform(b)` combines the variance of a context with the
352 /// variance of a type with the following meaning. If we are in a
353 /// context with variance `a`, and we encounter a type argument in
354 /// a position with variance `b`, then `a.xform(b)` is the new
355 /// variance with which the argument appears.
361 /// Here, the "ambient" variance starts as covariant. `*mut T` is
362 /// invariant with respect to `T`, so the variance in which the
363 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
364 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
365 /// respect to its type argument `T`, and hence the variance of
366 /// the `i32` here is `Invariant.xform(Covariant)`, which results
367 /// (again) in `Invariant`.
371 /// fn(*const Vec<i32>, *mut Vec<i32)
373 /// The ambient variance is covariant. A `fn` type is
374 /// contravariant with respect to its parameters, so the variance
375 /// within which both pointer types appear is
376 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
377 /// T` is covariant with respect to `T`, so the variance within
378 /// which the first `Vec<i32>` appears is
379 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
380 /// is true for its `i32` argument. In the `*mut T` case, the
381 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
382 /// and hence the outermost type is `Invariant` with respect to
383 /// `Vec<i32>` (and its `i32` argument).
385 /// Source: Figure 1 of "Taming the Wildcards:
386 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
387 pub fn xform(self, v: ty::Variance) -> ty::Variance {
389 // Figure 1, column 1.
390 (ty::Covariant, ty::Covariant) => ty::Covariant,
391 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
392 (ty::Covariant, ty::Invariant) => ty::Invariant,
393 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
395 // Figure 1, column 2.
396 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
397 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
398 (ty::Contravariant, ty::Invariant) => ty::Invariant,
399 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
401 // Figure 1, column 3.
402 (ty::Invariant, _) => ty::Invariant,
404 // Figure 1, column 4.
405 (ty::Bivariant, _) => ty::Bivariant,
410 // Contains information needed to resolve types and (in the future) look up
411 // the types of AST nodes.
412 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
413 pub struct CReaderCacheKey {
418 // Flags that we track on types. These flags are propagated upwards
419 // through the type during type construction, so that we can quickly
420 // check whether the type has various kinds of types in it without
421 // recursing over the type itself.
423 pub struct TypeFlags: u32 {
424 const HAS_PARAMS = 1 << 0;
425 const HAS_SELF = 1 << 1;
426 const HAS_TY_INFER = 1 << 2;
427 const HAS_RE_INFER = 1 << 3;
428 const HAS_RE_SKOL = 1 << 4;
430 /// Does this have any `ReEarlyBound` regions? Used to
431 /// determine whether substitition is required, since those
432 /// represent regions that are bound in a `ty::Generics` and
433 /// hence may be substituted.
434 const HAS_RE_EARLY_BOUND = 1 << 5;
436 /// Does this have any region that "appears free" in the type?
437 /// Basically anything but `ReLateBound` and `ReErased`.
438 const HAS_FREE_REGIONS = 1 << 6;
440 /// Is an error type reachable?
441 const HAS_TY_ERR = 1 << 7;
442 const HAS_PROJECTION = 1 << 8;
444 // FIXME: Rename this to the actual property since it's used for generators too
445 const HAS_TY_CLOSURE = 1 << 9;
447 // true if there are "names" of types and regions and so forth
448 // that are local to a particular fn
449 const HAS_FREE_LOCAL_NAMES = 1 << 10;
451 // Present if the type belongs in a local type context.
452 // Only set for TyInfer other than Fresh.
453 const KEEP_IN_LOCAL_TCX = 1 << 11;
455 // Is there a projection that does not involve a bound region?
456 // Currently we can't normalize projections w/ bound regions.
457 const HAS_NORMALIZABLE_PROJECTION = 1 << 12;
459 // Set if this includes a "canonical" type or region var --
460 // ought to be true only for the results of canonicalization.
461 const HAS_CANONICAL_VARS = 1 << 13;
463 /// Does this have any `ReLateBound` regions? Used to check
464 /// if a global bound is safe to evaluate.
465 const HAS_RE_LATE_BOUND = 1 << 14;
467 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
468 TypeFlags::HAS_SELF.bits |
469 TypeFlags::HAS_RE_EARLY_BOUND.bits;
471 // Flags representing the nominal content of a type,
472 // computed by FlagsComputation. If you add a new nominal
473 // flag, it should be added here too.
474 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
475 TypeFlags::HAS_SELF.bits |
476 TypeFlags::HAS_TY_INFER.bits |
477 TypeFlags::HAS_RE_INFER.bits |
478 TypeFlags::HAS_RE_SKOL.bits |
479 TypeFlags::HAS_RE_EARLY_BOUND.bits |
480 TypeFlags::HAS_FREE_REGIONS.bits |
481 TypeFlags::HAS_TY_ERR.bits |
482 TypeFlags::HAS_PROJECTION.bits |
483 TypeFlags::HAS_TY_CLOSURE.bits |
484 TypeFlags::HAS_FREE_LOCAL_NAMES.bits |
485 TypeFlags::KEEP_IN_LOCAL_TCX.bits |
486 TypeFlags::HAS_CANONICAL_VARS.bits |
487 TypeFlags::HAS_RE_LATE_BOUND.bits;
491 pub struct TyS<'tcx> {
492 pub sty: TypeVariants<'tcx>,
493 pub flags: TypeFlags,
495 /// This is a kind of confusing thing: it stores the smallest
498 /// (a) the binder itself captures nothing but
499 /// (b) all the late-bound things within the type are captured
500 /// by some sub-binder.
502 /// So, for a type without any late-bound things, like `u32`, this
503 /// will be INNERMOST, because that is the innermost binder that
504 /// captures nothing. But for a type `&'D u32`, where `'D` is a
505 /// late-bound region with debruijn index D, this would be D+1 --
506 /// the binder itself does not capture D, but D is captured by an
509 /// We call this concept an "exclusive" binder D (because all
510 /// debruijn indices within the type are contained within `0..D`
512 outer_exclusive_binder: ty::DebruijnIndex,
515 impl<'tcx> Ord for TyS<'tcx> {
516 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
517 self.sty.cmp(&other.sty)
521 impl<'tcx> PartialOrd for TyS<'tcx> {
522 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
523 Some(self.sty.cmp(&other.sty))
527 impl<'tcx> PartialEq for TyS<'tcx> {
529 fn eq(&self, other: &TyS<'tcx>) -> bool {
530 // (self as *const _) == (other as *const _)
531 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
534 impl<'tcx> Eq for TyS<'tcx> {}
536 impl<'tcx> Hash for TyS<'tcx> {
537 fn hash<H: Hasher>(&self, s: &mut H) {
538 (self as *const TyS).hash(s)
542 impl<'tcx> TyS<'tcx> {
543 pub fn is_primitive_ty(&self) -> bool {
545 TypeVariants::TyBool |
546 TypeVariants::TyChar |
547 TypeVariants::TyInt(_) |
548 TypeVariants::TyUint(_) |
549 TypeVariants::TyFloat(_) |
550 TypeVariants::TyInfer(InferTy::IntVar(_)) |
551 TypeVariants::TyInfer(InferTy::FloatVar(_)) |
552 TypeVariants::TyInfer(InferTy::FreshIntTy(_)) |
553 TypeVariants::TyInfer(InferTy::FreshFloatTy(_)) => true,
554 TypeVariants::TyRef(_, x, _) => x.is_primitive_ty(),
559 pub fn is_suggestable(&self) -> bool {
561 TypeVariants::TyAnon(..) |
562 TypeVariants::TyFnDef(..) |
563 TypeVariants::TyFnPtr(..) |
564 TypeVariants::TyDynamic(..) |
565 TypeVariants::TyClosure(..) |
566 TypeVariants::TyInfer(..) |
567 TypeVariants::TyProjection(..) => false,
573 impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for ty::TyS<'gcx> {
574 fn hash_stable<W: StableHasherResult>(&self,
575 hcx: &mut StableHashingContext<'a>,
576 hasher: &mut StableHasher<W>) {
580 // The other fields just provide fast access to information that is
581 // also contained in `sty`, so no need to hash them.
584 outer_exclusive_binder: _,
587 sty.hash_stable(hcx, hasher);
591 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
593 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
594 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
596 pub type CanonicalTy<'gcx> = Canonical<'gcx, Ty<'gcx>>;
599 /// A dummy type used to force Slice to by unsized without requiring fat pointers
600 type OpaqueSliceContents;
603 /// A wrapper for slices with the additional invariant
604 /// that the slice is interned and no other slice with
605 /// the same contents can exist in the same context.
606 /// This means we can use pointer for both
607 /// equality comparisons and hashing.
609 pub struct Slice<T> {
612 opaque: OpaqueSliceContents,
615 unsafe impl<T: Sync> Sync for Slice<T> {}
617 impl<T: Copy> Slice<T> {
619 fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx Slice<T> {
620 assert!(!mem::needs_drop::<T>());
621 assert!(mem::size_of::<T>() != 0);
622 assert!(slice.len() != 0);
624 // Align up the size of the len (usize) field
625 let align = mem::align_of::<T>();
626 let align_mask = align - 1;
627 let offset = mem::size_of::<usize>();
628 let offset = (offset + align_mask) & !align_mask;
630 let size = offset + slice.len() * mem::size_of::<T>();
632 let mem = arena.alloc_raw(
634 cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
636 let result = &mut *(mem.as_mut_ptr() as *mut Slice<T>);
638 result.len = slice.len();
640 // Write the elements
641 let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
642 arena_slice.copy_from_slice(slice);
649 impl<T: fmt::Debug> fmt::Debug for Slice<T> {
650 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
655 impl<T: Encodable> Encodable for Slice<T> {
657 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
662 impl<T> Ord for Slice<T> where T: Ord {
663 fn cmp(&self, other: &Slice<T>) -> Ordering {
664 if self == other { Ordering::Equal } else {
665 <[T] as Ord>::cmp(&**self, &**other)
670 impl<T> PartialOrd for Slice<T> where T: PartialOrd {
671 fn partial_cmp(&self, other: &Slice<T>) -> Option<Ordering> {
672 if self == other { Some(Ordering::Equal) } else {
673 <[T] as PartialOrd>::partial_cmp(&**self, &**other)
678 impl<T: PartialEq> PartialEq for Slice<T> {
680 fn eq(&self, other: &Slice<T>) -> bool {
681 (self as *const _) == (other as *const _)
684 impl<T: Eq> Eq for Slice<T> {}
686 impl<T> Hash for Slice<T> {
688 fn hash<H: Hasher>(&self, s: &mut H) {
689 (self as *const Slice<T>).hash(s)
693 impl<T> Deref for Slice<T> {
696 fn deref(&self) -> &[T] {
698 slice::from_raw_parts(self.data.as_ptr(), self.len)
703 impl<'a, T> IntoIterator for &'a Slice<T> {
705 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
707 fn into_iter(self) -> Self::IntoIter {
712 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {}
716 pub fn empty<'a>() -> &'a Slice<T> {
717 #[repr(align(64), C)]
718 struct EmptySlice([u8; 64]);
719 static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
720 assert!(mem::align_of::<T>() <= 64);
722 &*(&EMPTY_SLICE as *const _ as *const Slice<T>)
727 /// Upvars do not get their own node-id. Instead, we use the pair of
728 /// the original var id (that is, the root variable that is referenced
729 /// by the upvar) and the id of the closure expression.
730 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
732 pub var_id: hir::HirId,
733 pub closure_expr_id: LocalDefId,
736 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
737 pub enum BorrowKind {
738 /// Data must be immutable and is aliasable.
741 /// Data must be immutable but not aliasable. This kind of borrow
742 /// cannot currently be expressed by the user and is used only in
743 /// implicit closure bindings. It is needed when the closure
744 /// is borrowing or mutating a mutable referent, e.g.:
746 /// let x: &mut isize = ...;
747 /// let y = || *x += 5;
749 /// If we were to try to translate this closure into a more explicit
750 /// form, we'd encounter an error with the code as written:
752 /// struct Env { x: & &mut isize }
753 /// let x: &mut isize = ...;
754 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
755 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
757 /// This is then illegal because you cannot mutate a `&mut` found
758 /// in an aliasable location. To solve, you'd have to translate with
759 /// an `&mut` borrow:
761 /// struct Env { x: & &mut isize }
762 /// let x: &mut isize = ...;
763 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
764 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
766 /// Now the assignment to `**env.x` is legal, but creating a
767 /// mutable pointer to `x` is not because `x` is not mutable. We
768 /// could fix this by declaring `x` as `let mut x`. This is ok in
769 /// user code, if awkward, but extra weird for closures, since the
770 /// borrow is hidden.
772 /// So we introduce a "unique imm" borrow -- the referent is
773 /// immutable, but not aliasable. This solves the problem. For
774 /// simplicity, we don't give users the way to express this
775 /// borrow, it's just used when translating closures.
778 /// Data is mutable and not aliasable.
782 /// Information describing the capture of an upvar. This is computed
783 /// during `typeck`, specifically by `regionck`.
784 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
785 pub enum UpvarCapture<'tcx> {
786 /// Upvar is captured by value. This is always true when the
787 /// closure is labeled `move`, but can also be true in other cases
788 /// depending on inference.
791 /// Upvar is captured by reference.
792 ByRef(UpvarBorrow<'tcx>),
795 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
796 pub struct UpvarBorrow<'tcx> {
797 /// The kind of borrow: by-ref upvars have access to shared
798 /// immutable borrows, which are not part of the normal language
800 pub kind: BorrowKind,
802 /// Region of the resulting reference.
803 pub region: ty::Region<'tcx>,
806 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
808 #[derive(Copy, Clone)]
809 pub struct ClosureUpvar<'tcx> {
815 #[derive(Clone, Copy, PartialEq, Eq)]
816 pub enum IntVarValue {
818 UintType(ast::UintTy),
821 #[derive(Clone, Copy, PartialEq, Eq)]
822 pub struct FloatVarValue(pub ast::FloatTy);
824 impl ty::EarlyBoundRegion {
825 pub fn to_bound_region(&self) -> ty::BoundRegion {
826 ty::BoundRegion::BrNamed(self.def_id, self.name)
830 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
831 pub enum GenericParamDefKind {
835 object_lifetime_default: ObjectLifetimeDefault,
836 synthetic: Option<hir::SyntheticTyParamKind>,
840 #[derive(Clone, RustcEncodable, RustcDecodable)]
841 pub struct GenericParamDef {
842 pub name: InternedString,
846 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
847 /// on generic parameter `'a`/`T`, asserts data behind the parameter
848 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
849 pub pure_wrt_drop: bool,
851 pub kind: GenericParamDefKind,
854 impl GenericParamDef {
855 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
857 GenericParamDefKind::Lifetime => {
858 ty::EarlyBoundRegion {
864 _ => bug!("cannot convert a non-lifetime parameter def to an early bound region")
868 pub fn to_bound_region(&self) -> ty::BoundRegion {
870 GenericParamDefKind::Lifetime => {
871 self.to_early_bound_region_data().to_bound_region()
873 _ => bug!("cannot convert a non-lifetime parameter def to an early bound region")
878 pub struct GenericParamCount {
879 pub lifetimes: usize,
883 /// Information about the formal type/lifetime parameters associated
884 /// with an item or method. Analogous to hir::Generics.
886 /// The ordering of parameters is the same as in Subst (excluding child generics):
887 /// Self (optionally), Lifetime params..., Type params...
888 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
889 pub struct Generics {
890 pub parent: Option<DefId>,
891 pub parent_count: usize,
892 pub params: Vec<GenericParamDef>,
894 /// Reverse map to the `index` field of each `GenericParamDef`
895 pub param_def_id_to_index: FxHashMap<DefId, u32>,
898 pub has_late_bound_regions: Option<Span>,
901 impl<'a, 'gcx, 'tcx> Generics {
902 pub fn count(&self) -> usize {
903 self.parent_count + self.params.len()
906 pub fn own_counts(&self) -> GenericParamCount {
907 // We could cache this as a property of `GenericParamCount`, but
908 // the aim is to refactor this away entirely eventually and the
909 // presence of this method will be a constant reminder.
910 let mut own_counts = GenericParamCount {
915 for param in &self.params {
917 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
918 GenericParamDefKind::Type {..} => own_counts.types += 1,
925 pub fn requires_monomorphization(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
926 for param in &self.params {
928 GenericParamDefKind::Type {..} => return true,
929 GenericParamDefKind::Lifetime => {}
932 if let Some(parent_def_id) = self.parent {
933 let parent = tcx.generics_of(parent_def_id);
934 parent.requires_monomorphization(tcx)
940 pub fn region_param(&'tcx self,
941 param: &EarlyBoundRegion,
942 tcx: TyCtxt<'a, 'gcx, 'tcx>)
943 -> &'tcx GenericParamDef
945 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
946 let param = &self.params[index as usize];
948 ty::GenericParamDefKind::Lifetime => param,
949 _ => bug!("expected lifetime parameter, but found another generic parameter")
952 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
953 .region_param(param, tcx)
957 /// Returns the `GenericParamDef` associated with this `ParamTy`.
958 pub fn type_param(&'tcx self,
960 tcx: TyCtxt<'a, 'gcx, 'tcx>)
961 -> &'tcx GenericParamDef {
962 if let Some(index) = param.idx.checked_sub(self.parent_count as u32) {
963 let param = &self.params[index as usize];
965 ty::GenericParamDefKind::Type {..} => param,
966 _ => bug!("expected type parameter, but found another generic parameter")
969 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
970 .type_param(param, tcx)
975 /// Bounds on generics.
976 #[derive(Clone, Default)]
977 pub struct GenericPredicates<'tcx> {
978 pub parent: Option<DefId>,
979 pub predicates: Vec<Predicate<'tcx>>,
982 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
983 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
985 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
986 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
987 -> InstantiatedPredicates<'tcx> {
988 let mut instantiated = InstantiatedPredicates::empty();
989 self.instantiate_into(tcx, &mut instantiated, substs);
992 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
993 -> InstantiatedPredicates<'tcx> {
994 InstantiatedPredicates {
995 predicates: self.predicates.subst(tcx, substs)
999 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1000 instantiated: &mut InstantiatedPredicates<'tcx>,
1001 substs: &Substs<'tcx>) {
1002 if let Some(def_id) = self.parent {
1003 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
1005 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
1008 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1009 -> InstantiatedPredicates<'tcx> {
1010 let mut instantiated = InstantiatedPredicates::empty();
1011 self.instantiate_identity_into(tcx, &mut instantiated);
1015 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1016 instantiated: &mut InstantiatedPredicates<'tcx>) {
1017 if let Some(def_id) = self.parent {
1018 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
1020 instantiated.predicates.extend(&self.predicates)
1023 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1024 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
1025 -> InstantiatedPredicates<'tcx>
1027 assert_eq!(self.parent, None);
1028 InstantiatedPredicates {
1029 predicates: self.predicates.iter().map(|pred| {
1030 pred.subst_supertrait(tcx, poly_trait_ref)
1036 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1037 pub enum Predicate<'tcx> {
1038 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
1039 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1040 /// would be the type parameters.
1041 Trait(PolyTraitPredicate<'tcx>),
1044 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1047 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1049 /// where <T as TraitRef>::Name == X, approximately.
1050 /// See `ProjectionPredicate` struct for details.
1051 Projection(PolyProjectionPredicate<'tcx>),
1054 WellFormed(Ty<'tcx>),
1056 /// trait must be object-safe
1059 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
1060 /// for some substitutions `...` and T being a closure type.
1061 /// Satisfied (or refuted) once we know the closure's kind.
1062 ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
1065 Subtype(PolySubtypePredicate<'tcx>),
1067 /// Constant initializer must evaluate successfully.
1068 ConstEvaluatable(DefId, &'tcx Substs<'tcx>),
1071 /// The crate outlives map is computed during typeck and contains the
1072 /// outlives of every item in the local crate. You should not use it
1073 /// directly, because to do so will make your pass dependent on the
1074 /// HIR of every item in the local crate. Instead, use
1075 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1077 pub struct CratePredicatesMap<'tcx> {
1078 /// For each struct with outlive bounds, maps to a vector of the
1079 /// predicate of its outlive bounds. If an item has no outlives
1080 /// bounds, it will have no entry.
1081 pub predicates: FxHashMap<DefId, Lrc<Vec<ty::Predicate<'tcx>>>>,
1083 /// An empty vector, useful for cloning.
1084 pub empty_predicate: Lrc<Vec<ty::Predicate<'tcx>>>,
1087 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1088 fn as_ref(&self) -> &Predicate<'tcx> {
1093 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
1094 /// Performs a substitution suitable for going from a
1095 /// poly-trait-ref to supertraits that must hold if that
1096 /// poly-trait-ref holds. This is slightly different from a normal
1097 /// substitution in terms of what happens with bound regions. See
1098 /// lengthy comment below for details.
1099 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1100 trait_ref: &ty::PolyTraitRef<'tcx>)
1101 -> ty::Predicate<'tcx>
1103 // The interaction between HRTB and supertraits is not entirely
1104 // obvious. Let me walk you (and myself) through an example.
1106 // Let's start with an easy case. Consider two traits:
1108 // trait Foo<'a> : Bar<'a,'a> { }
1109 // trait Bar<'b,'c> { }
1111 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
1112 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
1113 // knew that `Foo<'x>` (for any 'x) then we also know that
1114 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1115 // normal substitution.
1117 // In terms of why this is sound, the idea is that whenever there
1118 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1119 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1120 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1123 // Another example to be careful of is this:
1125 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
1126 // trait Bar1<'b,'c> { }
1128 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
1129 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
1130 // reason is similar to the previous example: any impl of
1131 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
1132 // basically we would want to collapse the bound lifetimes from
1133 // the input (`trait_ref`) and the supertraits.
1135 // To achieve this in practice is fairly straightforward. Let's
1136 // consider the more complicated scenario:
1138 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
1139 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
1140 // where both `'x` and `'b` would have a DB index of 1.
1141 // The substitution from the input trait-ref is therefore going to be
1142 // `'a => 'x` (where `'x` has a DB index of 1).
1143 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1144 // early-bound parameter and `'b' is a late-bound parameter with a
1146 // - If we replace `'a` with `'x` from the input, it too will have
1147 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1148 // just as we wanted.
1150 // There is only one catch. If we just apply the substitution `'a
1151 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1152 // adjust the DB index because we substituting into a binder (it
1153 // tries to be so smart...) resulting in `for<'x> for<'b>
1154 // Bar1<'x,'b>` (we have no syntax for this, so use your
1155 // imagination). Basically the 'x will have DB index of 2 and 'b
1156 // will have DB index of 1. Not quite what we want. So we apply
1157 // the substitution to the *contents* of the trait reference,
1158 // rather than the trait reference itself (put another way, the
1159 // substitution code expects equal binding levels in the values
1160 // from the substitution and the value being substituted into, and
1161 // this trick achieves that).
1163 let substs = &trait_ref.skip_binder().substs;
1165 Predicate::Trait(ref binder) =>
1166 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1167 Predicate::Subtype(ref binder) =>
1168 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1169 Predicate::RegionOutlives(ref binder) =>
1170 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1171 Predicate::TypeOutlives(ref binder) =>
1172 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1173 Predicate::Projection(ref binder) =>
1174 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1175 Predicate::WellFormed(data) =>
1176 Predicate::WellFormed(data.subst(tcx, substs)),
1177 Predicate::ObjectSafe(trait_def_id) =>
1178 Predicate::ObjectSafe(trait_def_id),
1179 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1180 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1181 Predicate::ConstEvaluatable(def_id, const_substs) =>
1182 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1187 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1188 pub struct TraitPredicate<'tcx> {
1189 pub trait_ref: TraitRef<'tcx>
1191 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1193 impl<'tcx> TraitPredicate<'tcx> {
1194 pub fn def_id(&self) -> DefId {
1195 self.trait_ref.def_id
1198 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
1199 self.trait_ref.input_types()
1202 pub fn self_ty(&self) -> Ty<'tcx> {
1203 self.trait_ref.self_ty()
1207 impl<'tcx> PolyTraitPredicate<'tcx> {
1208 pub fn def_id(&self) -> DefId {
1209 // ok to skip binder since trait def-id does not care about regions
1210 self.skip_binder().def_id()
1214 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
1215 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
1216 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1217 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>,
1219 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>,
1221 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1222 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1224 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1225 pub struct SubtypePredicate<'tcx> {
1226 pub a_is_expected: bool,
1230 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1232 /// This kind of predicate has no *direct* correspondent in the
1233 /// syntax, but it roughly corresponds to the syntactic forms:
1235 /// 1. `T : TraitRef<..., Item=Type>`
1236 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1238 /// In particular, form #1 is "desugared" to the combination of a
1239 /// normal trait predicate (`T : TraitRef<...>`) and one of these
1240 /// predicates. Form #2 is a broader form in that it also permits
1241 /// equality between arbitrary types. Processing an instance of
1242 /// Form #2 eventually yields one of these `ProjectionPredicate`
1243 /// instances to normalize the LHS.
1244 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1245 pub struct ProjectionPredicate<'tcx> {
1246 pub projection_ty: ProjectionTy<'tcx>,
1250 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1252 impl<'tcx> PolyProjectionPredicate<'tcx> {
1253 /// Returns the def-id of the associated item being projected.
1254 pub fn item_def_id(&self) -> DefId {
1255 self.skip_binder().projection_ty.item_def_id
1258 pub fn to_poly_trait_ref(&self, tcx: TyCtxt) -> PolyTraitRef<'tcx> {
1259 // Note: unlike with TraitRef::to_poly_trait_ref(),
1260 // self.0.trait_ref is permitted to have escaping regions.
1261 // This is because here `self` has a `Binder` and so does our
1262 // return value, so we are preserving the number of binding
1264 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1267 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1268 self.map_bound(|predicate| predicate.ty)
1271 /// The DefId of the TraitItem for the associated type.
1273 /// Note that this is not the DefId of the TraitRef containing this
1274 /// associated type, which is in tcx.associated_item(projection_def_id()).container.
1275 pub fn projection_def_id(&self) -> DefId {
1276 // ok to skip binder since trait def-id does not care about regions
1277 self.skip_binder().projection_ty.item_def_id
1281 pub trait ToPolyTraitRef<'tcx> {
1282 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1285 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1286 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1287 ty::Binder::dummy(self.clone())
1291 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1292 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1293 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1297 pub trait ToPredicate<'tcx> {
1298 fn to_predicate(&self) -> Predicate<'tcx>;
1301 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1302 fn to_predicate(&self) -> Predicate<'tcx> {
1303 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1304 trait_ref: self.clone()
1309 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1310 fn to_predicate(&self) -> Predicate<'tcx> {
1311 ty::Predicate::Trait(self.to_poly_trait_predicate())
1315 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1316 fn to_predicate(&self) -> Predicate<'tcx> {
1317 Predicate::RegionOutlives(self.clone())
1321 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1322 fn to_predicate(&self) -> Predicate<'tcx> {
1323 Predicate::TypeOutlives(self.clone())
1327 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1328 fn to_predicate(&self) -> Predicate<'tcx> {
1329 Predicate::Projection(self.clone())
1333 impl<'tcx> Predicate<'tcx> {
1334 /// Iterates over the types in this predicate. Note that in all
1335 /// cases this is skipping over a binder, so late-bound regions
1336 /// with depth 0 are bound by the predicate.
1337 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1338 let vec: Vec<_> = match *self {
1339 ty::Predicate::Trait(ref data) => {
1340 data.skip_binder().input_types().collect()
1342 ty::Predicate::Subtype(binder) => {
1343 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1346 ty::Predicate::TypeOutlives(binder) => {
1347 vec![binder.skip_binder().0]
1349 ty::Predicate::RegionOutlives(..) => {
1352 ty::Predicate::Projection(ref data) => {
1353 let inner = data.skip_binder();
1354 inner.projection_ty.substs.types().chain(Some(inner.ty)).collect()
1356 ty::Predicate::WellFormed(data) => {
1359 ty::Predicate::ObjectSafe(_trait_def_id) => {
1362 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1363 closure_substs.substs.types().collect()
1365 ty::Predicate::ConstEvaluatable(_, substs) => {
1366 substs.types().collect()
1370 // The only reason to collect into a vector here is that I was
1371 // too lazy to make the full (somewhat complicated) iterator
1372 // type that would be needed here. But I wanted this fn to
1373 // return an iterator conceptually, rather than a `Vec`, so as
1374 // to be closer to `Ty::walk`.
1378 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1380 Predicate::Trait(ref t) => {
1381 Some(t.to_poly_trait_ref())
1383 Predicate::Projection(..) |
1384 Predicate::Subtype(..) |
1385 Predicate::RegionOutlives(..) |
1386 Predicate::WellFormed(..) |
1387 Predicate::ObjectSafe(..) |
1388 Predicate::ClosureKind(..) |
1389 Predicate::TypeOutlives(..) |
1390 Predicate::ConstEvaluatable(..) => {
1396 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1398 Predicate::TypeOutlives(data) => {
1401 Predicate::Trait(..) |
1402 Predicate::Projection(..) |
1403 Predicate::Subtype(..) |
1404 Predicate::RegionOutlives(..) |
1405 Predicate::WellFormed(..) |
1406 Predicate::ObjectSafe(..) |
1407 Predicate::ClosureKind(..) |
1408 Predicate::ConstEvaluatable(..) => {
1415 /// Represents the bounds declared on a particular set of type
1416 /// parameters. Should eventually be generalized into a flag list of
1417 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1418 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1419 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1420 /// the `GenericPredicates` are expressed in terms of the bound type
1421 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1422 /// represented a set of bounds for some particular instantiation,
1423 /// meaning that the generic parameters have been substituted with
1428 /// struct Foo<T,U:Bar<T>> { ... }
1430 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1431 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1432 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1433 /// [usize:Bar<isize>]]`.
1435 pub struct InstantiatedPredicates<'tcx> {
1436 pub predicates: Vec<Predicate<'tcx>>,
1439 impl<'tcx> InstantiatedPredicates<'tcx> {
1440 pub fn empty() -> InstantiatedPredicates<'tcx> {
1441 InstantiatedPredicates { predicates: vec![] }
1444 pub fn is_empty(&self) -> bool {
1445 self.predicates.is_empty()
1449 /// "Universes" are used during type- and trait-checking in the
1450 /// presence of `for<..>` binders to control what sets of names are
1451 /// visible. Universes are arranged into a tree: the root universe
1452 /// contains names that are always visible. But when you enter into
1453 /// some subuniverse, then it may add names that are only visible
1454 /// within that subtree (but it can still name the names of its
1455 /// ancestor universes).
1457 /// To make this more concrete, consider this program:
1461 /// fn bar<T>(x: T) {
1462 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1466 /// The struct name `Foo` is in the root universe U0. But the type
1467 /// parameter `T`, introduced on `bar`, is in a subuniverse U1 --
1468 /// i.e., within `bar`, we can name both `T` and `Foo`, but outside of
1469 /// `bar`, we cannot name `T`. Then, within the type of `y`, the
1470 /// region `'a` is in a subuniverse U2 of U1, because we can name it
1471 /// inside the fn type but not outside.
1473 /// Universes are related to **skolemization** -- which is a way of
1474 /// doing type- and trait-checking around these "forall" binders (also
1475 /// called **universal quantification**). The idea is that when, in
1476 /// the body of `bar`, we refer to `T` as a type, we aren't referring
1477 /// to any type in particular, but rather a kind of "fresh" type that
1478 /// is distinct from all other types we have actually declared. This
1479 /// is called a **skolemized** type, and we use universes to talk
1480 /// about this. In other words, a type name in universe 0 always
1481 /// corresponds to some "ground" type that the user declared, but a
1482 /// type name in a non-zero universe is a skolemized type -- an
1483 /// idealized representative of "types in general" that we use for
1484 /// checking generic functions.
1485 #[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
1486 pub struct UniverseIndex(u32);
1488 impl UniverseIndex {
1489 /// The root universe, where things that the user defined are
1491 pub const ROOT: Self = UniverseIndex(0);
1493 /// A "subuniverse" corresponds to being inside a `forall` quantifier.
1494 /// So, for example, suppose we have this type in universe `U`:
1497 /// for<'a> fn(&'a u32)
1500 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1501 /// subuniverse of `U` -- in this new universe, we can name the
1502 /// region `'a`, but that region was not nameable from `U` because
1503 /// it was not in scope there.
1504 pub fn subuniverse(self) -> UniverseIndex {
1505 UniverseIndex(self.0.checked_add(1).unwrap())
1508 pub fn as_u32(&self) -> u32 {
1512 pub fn as_usize(&self) -> usize {
1517 impl From<u32> for UniverseIndex {
1518 fn from(index: u32) -> Self {
1519 UniverseIndex(index)
1523 /// When type checking, we use the `ParamEnv` to track
1524 /// details about the set of where-clauses that are in scope at this
1525 /// particular point.
1526 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1527 pub struct ParamEnv<'tcx> {
1528 /// Obligations that the caller must satisfy. This is basically
1529 /// the set of bounds on the in-scope type parameters, translated
1530 /// into Obligations, and elaborated and normalized.
1531 pub caller_bounds: &'tcx Slice<ty::Predicate<'tcx>>,
1533 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1534 /// want `Reveal::All` -- note that this is always paired with an
1535 /// empty environment. To get that, use `ParamEnv::reveal()`.
1536 pub reveal: traits::Reveal,
1539 impl<'tcx> ParamEnv<'tcx> {
1540 /// Construct a trait environment suitable for contexts where
1541 /// there are no where clauses in scope. Hidden types (like `impl
1542 /// Trait`) are left hidden, so this is suitable for ordinary
1544 pub fn empty() -> Self {
1545 Self::new(ty::Slice::empty(), Reveal::UserFacing)
1548 /// Construct a trait environment with no where clauses in scope
1549 /// where the values of all `impl Trait` and other hidden types
1550 /// are revealed. This is suitable for monomorphized, post-typeck
1551 /// environments like codegen or doing optimizations.
1553 /// NB. If you want to have predicates in scope, use `ParamEnv::new`,
1554 /// or invoke `param_env.with_reveal_all()`.
1555 pub fn reveal_all() -> Self {
1556 Self::new(ty::Slice::empty(), Reveal::All)
1559 /// Construct a trait environment with the given set of predicates.
1560 pub fn new(caller_bounds: &'tcx ty::Slice<ty::Predicate<'tcx>>,
1563 ty::ParamEnv { caller_bounds, reveal }
1566 /// Returns a new parameter environment with the same clauses, but
1567 /// which "reveals" the true results of projections in all cases
1568 /// (even for associated types that are specializable). This is
1569 /// the desired behavior during codegen and certain other special
1570 /// contexts; normally though we want to use `Reveal::UserFacing`,
1571 /// which is the default.
1572 pub fn with_reveal_all(self) -> Self {
1573 ty::ParamEnv { reveal: Reveal::All, ..self }
1576 /// Returns this same environment but with no caller bounds.
1577 pub fn without_caller_bounds(self) -> Self {
1578 ty::ParamEnv { caller_bounds: ty::Slice::empty(), ..self }
1581 /// Creates a suitable environment in which to perform trait
1582 /// queries on the given value. When type-checking, this is simply
1583 /// the pair of the environment plus value. But when reveal is set to
1584 /// All, then if `value` does not reference any type parameters, we will
1585 /// pair it with the empty environment. This improves caching and is generally
1588 /// NB: We preserve the environment when type-checking because it
1589 /// is possible for the user to have wacky where-clauses like
1590 /// `where Box<u32>: Copy`, which are clearly never
1591 /// satisfiable. We generally want to behave as if they were true,
1592 /// although the surrounding function is never reachable.
1593 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1595 Reveal::UserFacing => {
1604 || value.needs_infer()
1605 || value.has_param_types()
1606 || value.has_self_ty()
1614 param_env: self.without_caller_bounds(),
1623 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1624 pub struct ParamEnvAnd<'tcx, T> {
1625 pub param_env: ParamEnv<'tcx>,
1629 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1630 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1631 (self.param_env, self.value)
1635 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'gcx, T>
1636 where T: HashStable<StableHashingContext<'a>>
1638 fn hash_stable<W: StableHasherResult>(&self,
1639 hcx: &mut StableHashingContext<'a>,
1640 hasher: &mut StableHasher<W>) {
1646 param_env.hash_stable(hcx, hasher);
1647 value.hash_stable(hcx, hasher);
1651 #[derive(Copy, Clone, Debug)]
1652 pub struct Destructor {
1653 /// The def-id of the destructor method
1658 pub struct AdtFlags: u32 {
1659 const NO_ADT_FLAGS = 0;
1660 const IS_ENUM = 1 << 0;
1661 const IS_PHANTOM_DATA = 1 << 1;
1662 const IS_FUNDAMENTAL = 1 << 2;
1663 const IS_UNION = 1 << 3;
1664 const IS_BOX = 1 << 4;
1665 /// Indicates whether this abstract data type will be expanded on in future (new
1666 /// fields/variants) and as such, whether downstream crates must match exhaustively on the
1667 /// fields/variants of this data type.
1669 /// See RFC 2008 (<https://github.com/rust-lang/rfcs/pull/2008>).
1670 const IS_NON_EXHAUSTIVE = 1 << 5;
1675 pub struct VariantDef {
1676 /// The variant's DefId. If this is a tuple-like struct,
1677 /// this is the DefId of the struct's ctor.
1679 pub name: Name, // struct's name if this is a struct
1680 pub discr: VariantDiscr,
1681 pub fields: Vec<FieldDef>,
1682 pub ctor_kind: CtorKind,
1685 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1686 pub enum VariantDiscr {
1687 /// Explicit value for this variant, i.e. `X = 123`.
1688 /// The `DefId` corresponds to the embedded constant.
1691 /// The previous variant's discriminant plus one.
1692 /// For efficiency reasons, the distance from the
1693 /// last `Explicit` discriminant is being stored,
1694 /// or `0` for the first variant, if it has none.
1699 pub struct FieldDef {
1702 pub vis: Visibility,
1705 /// The definition of an abstract data type - a struct or enum.
1707 /// These are all interned (by intern_adt_def) into the adt_defs
1711 pub variants: Vec<VariantDef>,
1713 pub repr: ReprOptions,
1716 impl PartialOrd for AdtDef {
1717 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1718 Some(self.cmp(&other))
1722 /// There should be only one AdtDef for each `did`, therefore
1723 /// it is fine to implement `Ord` only based on `did`.
1724 impl Ord for AdtDef {
1725 fn cmp(&self, other: &AdtDef) -> Ordering {
1726 self.did.cmp(&other.did)
1730 impl PartialEq for AdtDef {
1731 // AdtDef are always interned and this is part of TyS equality
1733 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1736 impl Eq for AdtDef {}
1738 impl Hash for AdtDef {
1740 fn hash<H: Hasher>(&self, s: &mut H) {
1741 (self as *const AdtDef).hash(s)
1745 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1746 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1751 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1754 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1755 fn hash_stable<W: StableHasherResult>(&self,
1756 hcx: &mut StableHashingContext<'a>,
1757 hasher: &mut StableHasher<W>) {
1759 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> =
1760 RefCell::new(FxHashMap());
1763 let hash: Fingerprint = CACHE.with(|cache| {
1764 let addr = self as *const AdtDef as usize;
1765 *cache.borrow_mut().entry(addr).or_insert_with(|| {
1773 let mut hasher = StableHasher::new();
1774 did.hash_stable(hcx, &mut hasher);
1775 variants.hash_stable(hcx, &mut hasher);
1776 flags.hash_stable(hcx, &mut hasher);
1777 repr.hash_stable(hcx, &mut hasher);
1783 hash.hash_stable(hcx, hasher);
1787 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
1788 pub enum AdtKind { Struct, Union, Enum }
1791 #[derive(RustcEncodable, RustcDecodable, Default)]
1792 pub struct ReprFlags: u8 {
1793 const IS_C = 1 << 0;
1794 const IS_SIMD = 1 << 1;
1795 const IS_TRANSPARENT = 1 << 2;
1796 // Internal only for now. If true, don't reorder fields.
1797 const IS_LINEAR = 1 << 3;
1799 // Any of these flags being set prevent field reordering optimisation.
1800 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1801 ReprFlags::IS_SIMD.bits |
1802 ReprFlags::IS_LINEAR.bits;
1806 impl_stable_hash_for!(struct ReprFlags {
1812 /// Represents the repr options provided by the user,
1813 #[derive(Copy, Clone, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1814 pub struct ReprOptions {
1815 pub int: Option<attr::IntType>,
1818 pub flags: ReprFlags,
1821 impl_stable_hash_for!(struct ReprOptions {
1829 pub fn new(tcx: TyCtxt, did: DefId) -> ReprOptions {
1830 let mut flags = ReprFlags::empty();
1831 let mut size = None;
1832 let mut max_align = 0;
1833 let mut min_pack = 0;
1834 for attr in tcx.get_attrs(did).iter() {
1835 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1836 flags.insert(match r {
1837 attr::ReprC => ReprFlags::IS_C,
1838 attr::ReprPacked(pack) => {
1839 min_pack = if min_pack > 0 {
1840 cmp::min(pack, min_pack)
1846 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
1847 attr::ReprSimd => ReprFlags::IS_SIMD,
1848 attr::ReprInt(i) => {
1852 attr::ReprAlign(align) => {
1853 max_align = cmp::max(align, max_align);
1860 // This is here instead of layout because the choice must make it into metadata.
1861 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1862 flags.insert(ReprFlags::IS_LINEAR);
1864 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
1868 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1870 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1872 pub fn packed(&self) -> bool { self.pack > 0 }
1874 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
1876 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1878 pub fn discr_type(&self) -> attr::IntType {
1879 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
1882 /// Returns true if this `#[repr()]` should inhabit "smart enum
1883 /// layout" optimizations, such as representing `Foo<&T>` as a
1885 pub fn inhibit_enum_layout_opt(&self) -> bool {
1886 self.c() || self.int.is_some()
1889 /// Returns true if this `#[repr()]` should inhibit struct field reordering
1890 /// optimizations, such as with repr(C) or repr(packed(1)).
1891 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
1892 !(self.flags & ReprFlags::IS_UNOPTIMISABLE).is_empty() || (self.pack == 1)
1896 impl<'a, 'gcx, 'tcx> AdtDef {
1900 variants: Vec<VariantDef>,
1901 repr: ReprOptions) -> Self {
1902 let mut flags = AdtFlags::NO_ADT_FLAGS;
1903 let attrs = tcx.get_attrs(did);
1904 if attr::contains_name(&attrs, "fundamental") {
1905 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1907 if Some(did) == tcx.lang_items().phantom_data() {
1908 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1910 if Some(did) == tcx.lang_items().owned_box() {
1911 flags = flags | AdtFlags::IS_BOX;
1913 if tcx.has_attr(did, "non_exhaustive") {
1914 flags = flags | AdtFlags::IS_NON_EXHAUSTIVE;
1917 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
1918 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
1919 AdtKind::Struct => {}
1930 pub fn is_struct(&self) -> bool {
1931 !self.is_union() && !self.is_enum()
1935 pub fn is_union(&self) -> bool {
1936 self.flags.intersects(AdtFlags::IS_UNION)
1940 pub fn is_enum(&self) -> bool {
1941 self.flags.intersects(AdtFlags::IS_ENUM)
1945 pub fn is_non_exhaustive(&self) -> bool {
1946 self.flags.intersects(AdtFlags::IS_NON_EXHAUSTIVE)
1949 /// Returns the kind of the ADT - Struct or Enum.
1951 pub fn adt_kind(&self) -> AdtKind {
1954 } else if self.is_union() {
1961 pub fn descr(&self) -> &'static str {
1962 match self.adt_kind() {
1963 AdtKind::Struct => "struct",
1964 AdtKind::Union => "union",
1965 AdtKind::Enum => "enum",
1969 pub fn variant_descr(&self) -> &'static str {
1970 match self.adt_kind() {
1971 AdtKind::Struct => "struct",
1972 AdtKind::Union => "union",
1973 AdtKind::Enum => "variant",
1977 /// Returns whether this type is #[fundamental] for the purposes
1978 /// of coherence checking.
1980 pub fn is_fundamental(&self) -> bool {
1981 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
1984 /// Returns true if this is PhantomData<T>.
1986 pub fn is_phantom_data(&self) -> bool {
1987 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
1990 /// Returns true if this is Box<T>.
1992 pub fn is_box(&self) -> bool {
1993 self.flags.intersects(AdtFlags::IS_BOX)
1996 /// Returns whether this type has a destructor.
1997 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
1998 self.destructor(tcx).is_some()
2001 /// Asserts this is a struct or union and returns its unique variant.
2002 pub fn non_enum_variant(&self) -> &VariantDef {
2003 assert!(self.is_struct() || self.is_union());
2008 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
2009 tcx.predicates_of(self.did)
2012 /// Returns an iterator over all fields contained
2015 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
2016 self.variants.iter().flat_map(|v| v.fields.iter())
2019 pub fn is_payloadfree(&self) -> bool {
2020 !self.variants.is_empty() &&
2021 self.variants.iter().all(|v| v.fields.is_empty())
2024 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
2027 .find(|v| v.did == vid)
2028 .expect("variant_with_id: unknown variant")
2031 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
2034 .position(|v| v.did == vid)
2035 .expect("variant_index_with_id: unknown variant")
2038 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
2040 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
2041 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
2042 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.non_enum_variant(),
2043 _ => bug!("unexpected def {:?} in variant_of_def", def)
2048 pub fn eval_explicit_discr(
2050 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2052 ) -> Option<Discr<'tcx>> {
2053 let param_env = ParamEnv::empty();
2054 let repr_type = self.repr.discr_type();
2055 let substs = Substs::identity_for_item(tcx.global_tcx(), expr_did);
2056 let instance = ty::Instance::new(expr_did, substs);
2057 let cid = GlobalId {
2061 match tcx.const_eval(param_env.and(cid)) {
2063 // FIXME: Find the right type and use it instead of `val.ty` here
2064 if let Some(b) = val.assert_bits(tcx.global_tcx(), param_env.and(val.ty)) {
2065 trace!("discriminants: {} ({:?})", b, repr_type);
2071 info!("invalid enum discriminant: {:#?}", val);
2072 ::mir::interpret::struct_error(
2073 tcx.at(tcx.def_span(expr_did)),
2074 "constant evaluation of enum discriminant resulted in non-integer",
2080 err.report_as_error(
2081 tcx.at(tcx.def_span(expr_did)),
2082 "could not evaluate enum discriminant",
2084 if !expr_did.is_local() {
2085 span_bug!(tcx.def_span(expr_did),
2086 "variant discriminant evaluation succeeded \
2087 in its crate but failed locally");
2095 pub fn discriminants(
2097 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2098 ) -> impl Iterator<Item=Discr<'tcx>> + Captures<'gcx> + 'a {
2099 let repr_type = self.repr.discr_type();
2100 let initial = repr_type.initial_discriminant(tcx.global_tcx());
2101 let mut prev_discr = None::<Discr<'tcx>>;
2102 self.variants.iter().map(move |v| {
2103 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
2104 if let VariantDiscr::Explicit(expr_did) = v.discr {
2105 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
2109 prev_discr = Some(discr);
2115 /// Compute the discriminant value used by a specific variant.
2116 /// Unlike `discriminants`, this is (amortized) constant-time,
2117 /// only doing at most one query for evaluating an explicit
2118 /// discriminant (the last one before the requested variant),
2119 /// assuming there are no constant-evaluation errors there.
2120 pub fn discriminant_for_variant(&self,
2121 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2122 variant_index: usize)
2124 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2125 let explicit_value = val
2126 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2127 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx.global_tcx()));
2128 explicit_value.checked_add(tcx, offset as u128).0
2131 /// Yields a DefId for the discriminant and an offset to add to it
2132 /// Alternatively, if there is no explicit discriminant, returns the
2133 /// inferred discriminant directly
2134 pub fn discriminant_def_for_variant(
2136 variant_index: usize,
2137 ) -> (Option<DefId>, usize) {
2138 let mut explicit_index = variant_index;
2141 match self.variants[explicit_index].discr {
2142 ty::VariantDiscr::Relative(0) => {
2146 ty::VariantDiscr::Relative(distance) => {
2147 explicit_index -= distance;
2149 ty::VariantDiscr::Explicit(did) => {
2150 expr_did = Some(did);
2155 (expr_did, variant_index - explicit_index)
2158 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
2159 tcx.adt_destructor(self.did)
2162 /// Returns a list of types such that `Self: Sized` if and only
2163 /// if that type is Sized, or `TyErr` if this type is recursive.
2165 /// Oddly enough, checking that the sized-constraint is Sized is
2166 /// actually more expressive than checking all members:
2167 /// the Sized trait is inductive, so an associated type that references
2168 /// Self would prevent its containing ADT from being Sized.
2170 /// Due to normalization being eager, this applies even if
2171 /// the associated type is behind a pointer, e.g. issue #31299.
2172 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
2173 match tcx.try_adt_sized_constraint(DUMMY_SP, self.did) {
2176 debug!("adt_sized_constraint: {:?} is recursive", self);
2177 // This should be reported as an error by `check_representable`.
2179 // Consider the type as Sized in the meanwhile to avoid
2180 // further errors. Delay our `bug` diagnostic here to get
2181 // emitted later as well in case we accidentally otherwise don't
2184 tcx.intern_type_list(&[tcx.types.err])
2189 fn sized_constraint_for_ty(&self,
2190 tcx: TyCtxt<'a, 'tcx, 'tcx>,
2193 let result = match ty.sty {
2194 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
2195 TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
2196 TyArray(..) | TyClosure(..) | TyGenerator(..) | TyNever => {
2205 TyGeneratorWitness(..) => {
2206 // these are never sized - return the target type
2210 TyTuple(ref tys) => {
2213 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
2217 TyAdt(adt, substs) => {
2219 let adt_tys = adt.sized_constraint(tcx);
2220 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
2223 .map(|ty| ty.subst(tcx, substs))
2224 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2228 TyProjection(..) | TyAnon(..) => {
2229 // must calculate explicitly.
2230 // FIXME: consider special-casing always-Sized projections
2235 // perf hack: if there is a `T: Sized` bound, then
2236 // we know that `T` is Sized and do not need to check
2239 let sized_trait = match tcx.lang_items().sized_trait() {
2241 _ => return vec![ty]
2243 let sized_predicate = Binder::dummy(TraitRef {
2244 def_id: sized_trait,
2245 substs: tcx.mk_substs_trait(ty, &[])
2247 let predicates = tcx.predicates_of(self.did).predicates;
2248 if predicates.into_iter().any(|p| p == sized_predicate) {
2256 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2260 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2265 impl<'a, 'gcx, 'tcx> FieldDef {
2266 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
2267 tcx.type_of(self.did).subst(tcx, subst)
2271 /// Represents the various closure traits in the Rust language. This
2272 /// will determine the type of the environment (`self`, in the
2273 /// desuaring) argument that the closure expects.
2275 /// You can get the environment type of a closure using
2276 /// `tcx.closure_env_ty()`.
2277 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
2278 pub enum ClosureKind {
2279 // Warning: Ordering is significant here! The ordering is chosen
2280 // because the trait Fn is a subtrait of FnMut and so in turn, and
2281 // hence we order it so that Fn < FnMut < FnOnce.
2287 impl<'a, 'tcx> ClosureKind {
2288 // This is the initial value used when doing upvar inference.
2289 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2291 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
2293 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
2294 ClosureKind::FnMut => {
2295 tcx.require_lang_item(FnMutTraitLangItem)
2297 ClosureKind::FnOnce => {
2298 tcx.require_lang_item(FnOnceTraitLangItem)
2303 /// True if this a type that impls this closure kind
2304 /// must also implement `other`.
2305 pub fn extends(self, other: ty::ClosureKind) -> bool {
2306 match (self, other) {
2307 (ClosureKind::Fn, ClosureKind::Fn) => true,
2308 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2309 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2310 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2311 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2312 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2317 /// Returns the representative scalar type for this closure kind.
2318 /// See `TyS::to_opt_closure_kind` for more details.
2319 pub fn to_ty(self, tcx: TyCtxt<'_, '_, 'tcx>) -> Ty<'tcx> {
2321 ty::ClosureKind::Fn => tcx.types.i8,
2322 ty::ClosureKind::FnMut => tcx.types.i16,
2323 ty::ClosureKind::FnOnce => tcx.types.i32,
2328 impl<'tcx> TyS<'tcx> {
2329 /// Iterator that walks `self` and any types reachable from
2330 /// `self`, in depth-first order. Note that just walks the types
2331 /// that appear in `self`, it does not descend into the fields of
2332 /// structs or variants. For example:
2335 /// isize => { isize }
2336 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2337 /// [isize] => { [isize], isize }
2339 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2340 TypeWalker::new(self)
2343 /// Iterator that walks the immediate children of `self`. Hence
2344 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2345 /// (but not `i32`, like `walk`).
2346 pub fn walk_shallow(&'tcx self) -> AccIntoIter<walk::TypeWalkerArray<'tcx>> {
2347 walk::walk_shallow(self)
2350 /// Walks `ty` and any types appearing within `ty`, invoking the
2351 /// callback `f` on each type. If the callback returns false, then the
2352 /// children of the current type are ignored.
2354 /// Note: prefer `ty.walk()` where possible.
2355 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2356 where F : FnMut(Ty<'tcx>) -> bool
2358 let mut walker = self.walk();
2359 while let Some(ty) = walker.next() {
2361 walker.skip_current_subtree();
2368 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2370 hir::MutMutable => MutBorrow,
2371 hir::MutImmutable => ImmBorrow,
2375 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2376 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2377 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2379 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2381 MutBorrow => hir::MutMutable,
2382 ImmBorrow => hir::MutImmutable,
2384 // We have no type corresponding to a unique imm borrow, so
2385 // use `&mut`. It gives all the capabilities of an `&uniq`
2386 // and hence is a safe "over approximation".
2387 UniqueImmBorrow => hir::MutMutable,
2391 pub fn to_user_str(&self) -> &'static str {
2393 MutBorrow => "mutable",
2394 ImmBorrow => "immutable",
2395 UniqueImmBorrow => "uniquely immutable",
2400 #[derive(Debug, Clone)]
2401 pub enum Attributes<'gcx> {
2402 Owned(Lrc<[ast::Attribute]>),
2403 Borrowed(&'gcx [ast::Attribute])
2406 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2407 type Target = [ast::Attribute];
2409 fn deref(&self) -> &[ast::Attribute] {
2411 &Attributes::Owned(ref data) => &data,
2412 &Attributes::Borrowed(data) => data
2417 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2418 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2419 self.typeck_tables_of(self.hir.body_owner_def_id(body))
2422 /// Returns an iterator of the def-ids for all body-owners in this
2423 /// crate. If you would prefer to iterate over the bodies
2424 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
2427 ) -> impl Iterator<Item = DefId> + Captures<'tcx> + Captures<'gcx> + 'a {
2431 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
2434 pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
2435 par_iter(&self.hir.krate().body_ids).for_each(|&body_id| {
2436 f(self.hir.body_owner_def_id(body_id))
2440 pub fn expr_span(self, id: NodeId) -> Span {
2441 match self.hir.find(id) {
2442 Some(hir_map::NodeExpr(e)) => {
2446 bug!("Node id {} is not an expr: {:?}", id, f);
2449 bug!("Node id {} is not present in the node map", id);
2454 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2455 self.associated_items(id)
2456 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2460 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2461 self.associated_items(did).any(|item| {
2462 item.relevant_for_never()
2466 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2467 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2468 match self.hir.get(node_id) {
2469 hir_map::NodeTraitItem(_) | hir_map::NodeImplItem(_) => true,
2473 match self.describe_def(def_id).expect("no def for def-id") {
2474 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2479 if is_associated_item {
2480 Some(self.associated_item(def_id))
2486 fn associated_item_from_trait_item_ref(self,
2487 parent_def_id: DefId,
2488 parent_vis: &hir::Visibility,
2489 trait_item_ref: &hir::TraitItemRef)
2491 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2492 let (kind, has_self) = match trait_item_ref.kind {
2493 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2494 hir::AssociatedItemKind::Method { has_self } => {
2495 (ty::AssociatedKind::Method, has_self)
2497 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2498 hir::AssociatedItemKind::Existential => bug!("only impls can have existentials"),
2502 ident: trait_item_ref.ident,
2504 // Visibility of trait items is inherited from their traits.
2505 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2506 defaultness: trait_item_ref.defaultness,
2508 container: TraitContainer(parent_def_id),
2509 method_has_self_argument: has_self
2513 fn associated_item_from_impl_item_ref(self,
2514 parent_def_id: DefId,
2515 impl_item_ref: &hir::ImplItemRef)
2517 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2518 let (kind, has_self) = match impl_item_ref.kind {
2519 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2520 hir::AssociatedItemKind::Method { has_self } => {
2521 (ty::AssociatedKind::Method, has_self)
2523 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2524 hir::AssociatedItemKind::Existential => (ty::AssociatedKind::Existential, false),
2528 ident: impl_item_ref.ident,
2530 // Visibility of trait impl items doesn't matter.
2531 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2532 defaultness: impl_item_ref.defaultness,
2534 container: ImplContainer(parent_def_id),
2535 method_has_self_argument: has_self
2539 pub fn field_index(self, node_id: NodeId, tables: &TypeckTables) -> usize {
2540 let hir_id = self.hir.node_to_hir_id(node_id);
2541 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2544 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2545 variant.fields.iter().position(|field| {
2546 self.adjust_ident(ident, variant.did, DUMMY_NODE_ID).0 == field.ident.modern()
2550 pub fn associated_items(
2553 ) -> impl Iterator<Item = AssociatedItem> + 'a {
2554 let def_ids = self.associated_item_def_ids(def_id);
2555 Box::new((0..def_ids.len()).map(move |i| self.associated_item(def_ids[i])))
2556 as Box<dyn Iterator<Item = AssociatedItem> + 'a>
2559 /// Returns true if the impls are the same polarity and are implementing
2560 /// a trait which contains no items
2561 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2562 if !self.features().overlapping_marker_traits {
2565 let trait1_is_empty = self.impl_trait_ref(def_id1)
2566 .map_or(false, |trait_ref| {
2567 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2569 let trait2_is_empty = self.impl_trait_ref(def_id2)
2570 .map_or(false, |trait_ref| {
2571 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2573 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2578 // Returns `ty::VariantDef` if `def` refers to a struct,
2579 // or variant or their constructors, panics otherwise.
2580 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2582 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2583 let enum_did = self.parent_def_id(did).unwrap();
2584 self.adt_def(enum_did).variant_with_id(did)
2586 Def::Struct(did) | Def::Union(did) => {
2587 self.adt_def(did).non_enum_variant()
2589 Def::StructCtor(ctor_did, ..) => {
2590 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2591 self.adt_def(did).non_enum_variant()
2593 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2597 /// Given a `VariantDef`, returns the def-id of the `AdtDef` of which it is a part.
2598 pub fn adt_def_id_of_variant(self, variant_def: &'tcx VariantDef) -> DefId {
2599 let def_key = self.def_key(variant_def.did);
2600 match def_key.disambiguated_data.data {
2601 // for enum variants and tuple structs, the def-id of the ADT itself
2602 // is the *parent* of the variant
2603 DefPathData::EnumVariant(..) | DefPathData::StructCtor =>
2604 DefId { krate: variant_def.did.krate, index: def_key.parent.unwrap() },
2606 // otherwise, for structs and unions, they share a def-id
2607 _ => variant_def.did,
2611 pub fn item_name(self, id: DefId) -> InternedString {
2612 if id.index == CRATE_DEF_INDEX {
2613 self.original_crate_name(id.krate).as_interned_str()
2615 let def_key = self.def_key(id);
2616 // The name of a StructCtor is that of its struct parent.
2617 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2618 self.item_name(DefId {
2620 index: def_key.parent.unwrap()
2623 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2624 bug!("item_name: no name for {:?}", self.def_path(id));
2630 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2631 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2635 ty::InstanceDef::Item(did) => {
2636 self.optimized_mir(did)
2638 ty::InstanceDef::Intrinsic(..) |
2639 ty::InstanceDef::FnPtrShim(..) |
2640 ty::InstanceDef::Virtual(..) |
2641 ty::InstanceDef::ClosureOnceShim { .. } |
2642 ty::InstanceDef::DropGlue(..) |
2643 ty::InstanceDef::CloneShim(..) => {
2644 self.mir_shims(instance)
2649 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2650 /// Returns None if there is no MIR for the DefId
2651 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2652 if self.is_mir_available(did) {
2653 Some(self.optimized_mir(did))
2659 /// Get the attributes of a definition.
2660 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2661 if let Some(id) = self.hir.as_local_node_id(did) {
2662 Attributes::Borrowed(self.hir.attrs(id))
2664 Attributes::Owned(self.item_attrs(did))
2668 /// Determine whether an item is annotated with an attribute
2669 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2670 attr::contains_name(&self.get_attrs(did), attr)
2673 /// Returns true if this is an `auto trait`.
2674 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
2675 self.trait_def(trait_def_id).has_auto_impl
2678 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
2679 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
2682 /// Given the def_id of an impl, return the def_id of the trait it implements.
2683 /// If it implements no trait, return `None`.
2684 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2685 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2688 /// If the given def ID describes a method belonging to an impl, return the
2689 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2690 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2691 let item = if def_id.krate != LOCAL_CRATE {
2692 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2693 Some(self.associated_item(def_id))
2698 self.opt_associated_item(def_id)
2702 Some(trait_item) => {
2703 match trait_item.container {
2704 TraitContainer(_) => None,
2705 ImplContainer(def_id) => Some(def_id),
2712 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2713 /// with the name of the crate containing the impl.
2714 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2715 if impl_did.is_local() {
2716 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2717 Ok(self.hir.span(node_id))
2719 Err(self.crate_name(impl_did.krate))
2723 // Hygienically compare a use-site name (`use_name`) for a field or an associated item with its
2724 // supposed definition name (`def_name`). The method also needs `DefId` of the supposed
2725 // definition's parent/scope to perform comparison.
2726 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
2727 self.adjust_ident(use_name, def_parent_def_id, DUMMY_NODE_ID).0 == def_name.modern()
2730 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
2731 ident = ident.modern();
2732 let target_expansion = match scope.krate {
2733 LOCAL_CRATE => self.hir.definitions().expansion_that_defined(scope.index),
2736 let scope = match ident.span.adjust(target_expansion) {
2737 Some(actual_expansion) =>
2738 self.hir.definitions().parent_module_of_macro_def(actual_expansion),
2739 None if block == DUMMY_NODE_ID => DefId::local(CRATE_DEF_INDEX), // Dummy DefId
2740 None => self.hir.get_module_parent(block),
2746 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2747 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2748 F: FnOnce(&[hir::Freevar]) -> T,
2750 let def_id = self.hir.local_def_id(fid);
2751 match self.freevars(def_id) {
2758 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
2761 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2762 let parent_id = tcx.hir.get_parent(id);
2763 let parent_def_id = tcx.hir.local_def_id(parent_id);
2764 let parent_item = tcx.hir.expect_item(parent_id);
2765 match parent_item.node {
2766 hir::ItemKind::Impl(.., ref impl_item_refs) => {
2767 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2768 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2770 debug_assert_eq!(assoc_item.def_id, def_id);
2775 hir::ItemKind::Trait(.., ref trait_item_refs) => {
2776 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2777 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2780 debug_assert_eq!(assoc_item.def_id, def_id);
2788 span_bug!(parent_item.span,
2789 "unexpected parent of trait or impl item or item not found: {:?}",
2793 /// Calculates the Sized-constraint.
2795 /// In fact, there are only a few options for the types in the constraint:
2796 /// - an obviously-unsized type
2797 /// - a type parameter or projection whose Sizedness can't be known
2798 /// - a tuple of type parameters or projections, if there are multiple
2800 /// - a TyError, if a type contained itself. The representability
2801 /// check should catch this case.
2802 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2804 -> &'tcx [Ty<'tcx>] {
2805 let def = tcx.adt_def(def_id);
2807 let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| {
2810 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2813 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2818 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2820 -> Lrc<Vec<DefId>> {
2821 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2822 let item = tcx.hir.expect_item(id);
2823 let vec: Vec<_> = match item.node {
2824 hir::ItemKind::Trait(.., ref trait_item_refs) => {
2825 trait_item_refs.iter()
2826 .map(|trait_item_ref| trait_item_ref.id)
2827 .map(|id| tcx.hir.local_def_id(id.node_id))
2830 hir::ItemKind::Impl(.., ref impl_item_refs) => {
2831 impl_item_refs.iter()
2832 .map(|impl_item_ref| impl_item_ref.id)
2833 .map(|id| tcx.hir.local_def_id(id.node_id))
2836 hir::ItemKind::TraitAlias(..) => vec![],
2837 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2842 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
2843 tcx.hir.span_if_local(def_id).unwrap()
2846 /// If the given def ID describes an item belonging to a trait,
2847 /// return the ID of the trait that the trait item belongs to.
2848 /// Otherwise, return `None`.
2849 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
2850 tcx.opt_associated_item(def_id)
2851 .and_then(|associated_item| {
2852 match associated_item.container {
2853 TraitContainer(def_id) => Some(def_id),
2854 ImplContainer(_) => None
2859 /// See `ParamEnv` struct def'n for details.
2860 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2864 // The param_env of an impl Trait type is its defining function's param_env
2865 if let Some(Def::Existential(_)) = tcx.describe_def(def_id) {
2866 if let Some(node_id) = tcx.hir.as_local_node_id(def_id) {
2867 if let hir::map::NodeItem(item) = tcx.hir.get(node_id) {
2868 if let hir::ItemKind::Existential(ref exist_ty) = item.node {
2869 if let Some(parent) = exist_ty.impl_trait_fn {
2870 return param_env(tcx, parent);
2876 // Compute the bounds on Self and the type parameters.
2878 let InstantiatedPredicates { predicates } =
2879 tcx.predicates_of(def_id).instantiate_identity(tcx);
2881 // Finally, we have to normalize the bounds in the environment, in
2882 // case they contain any associated type projections. This process
2883 // can yield errors if the put in illegal associated types, like
2884 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2885 // report these errors right here; this doesn't actually feel
2886 // right to me, because constructing the environment feels like a
2887 // kind of a "idempotent" action, but I'm not sure where would be
2888 // a better place. In practice, we construct environments for
2889 // every fn once during type checking, and we'll abort if there
2890 // are any errors at that point, so after type checking you can be
2891 // sure that this will succeed without errors anyway.
2893 let unnormalized_env = ty::ParamEnv::new(tcx.intern_predicates(&predicates),
2894 traits::Reveal::UserFacing);
2896 let body_id = tcx.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
2897 tcx.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_id)
2899 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
2900 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
2903 fn crate_disambiguator<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2904 crate_num: CrateNum) -> CrateDisambiguator {
2905 assert_eq!(crate_num, LOCAL_CRATE);
2906 tcx.sess.local_crate_disambiguator()
2909 fn original_crate_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2910 crate_num: CrateNum) -> Symbol {
2911 assert_eq!(crate_num, LOCAL_CRATE);
2912 tcx.crate_name.clone()
2915 fn crate_hash<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2916 crate_num: CrateNum)
2918 assert_eq!(crate_num, LOCAL_CRATE);
2922 fn instance_def_size_estimate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2923 instance_def: InstanceDef<'tcx>)
2925 match instance_def {
2926 InstanceDef::Item(..) |
2927 InstanceDef::DropGlue(..) => {
2928 let mir = tcx.instance_mir(instance_def);
2929 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
2931 // Estimate the size of other compiler-generated shims to be 1.
2936 pub fn provide(providers: &mut ty::query::Providers) {
2937 context::provide(providers);
2938 erase_regions::provide(providers);
2939 layout::provide(providers);
2940 util::provide(providers);
2941 *providers = ty::query::Providers {
2943 associated_item_def_ids,
2944 adt_sized_constraint,
2948 crate_disambiguator,
2949 original_crate_name,
2951 trait_impls_of: trait_def::trait_impls_of_provider,
2952 instance_def_size_estimate,
2957 /// A map for the local crate mapping each type to a vector of its
2958 /// inherent impls. This is not meant to be used outside of coherence;
2959 /// rather, you should request the vector for a specific type via
2960 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2961 /// (constructing this map requires touching the entire crate).
2962 #[derive(Clone, Debug)]
2963 pub struct CrateInherentImpls {
2964 pub inherent_impls: DefIdMap<Lrc<Vec<DefId>>>,
2967 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
2968 pub struct SymbolName {
2969 // FIXME: we don't rely on interning or equality here - better have
2970 // this be a `&'tcx str`.
2971 pub name: InternedString
2974 impl_stable_hash_for!(struct self::SymbolName {
2979 pub fn new(name: &str) -> SymbolName {
2981 name: Symbol::intern(name).as_interned_str()
2985 pub fn as_str(&self) -> LocalInternedString {
2990 impl fmt::Display for SymbolName {
2991 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2992 fmt::Display::fmt(&self.name, fmt)
2996 impl fmt::Debug for SymbolName {
2997 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2998 fmt::Display::fmt(&self.name, fmt)