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};
53 use syntax::ast::{self, DUMMY_NODE_ID, Name, Ident, NodeId};
55 use syntax::ext::hygiene::Mark;
56 use syntax::symbol::{keywords, Symbol, LocalInternedString, InternedString};
57 use syntax_pos::{DUMMY_SP, Span};
60 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
61 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
66 pub use self::sty::{Binder, BoundTy, BoundTyKind, BoundVar, DebruijnIndex, INNERMOST};
67 pub use self::sty::{FnSig, GenSig, CanonicalPolyFnSig, PolyFnSig, PolyGenSig};
68 pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
69 pub use self::sty::{ClosureSubsts, GeneratorSubsts, UpvarSubsts, TypeAndMut};
70 pub use self::sty::{TraitRef, TyKind, PolyTraitRef};
71 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
72 pub use self::sty::{ExistentialProjection, PolyExistentialProjection, Const};
73 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
74 pub use self::sty::RegionKind;
75 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid};
76 pub use self::sty::BoundRegion::*;
77 pub use self::sty::InferTy::*;
78 pub use self::sty::RegionKind::*;
79 pub use self::sty::TyKind::*;
81 pub use self::binding::BindingMode;
82 pub use self::binding::BindingMode::*;
84 pub use self::context::{TyCtxt, FreeRegionInfo, GlobalArenas, AllArenas, tls, keep_local};
85 pub use self::context::{Lift, TypeckTables, CtxtInterners};
87 pub use self::instance::{Instance, InstanceDef};
89 pub use self::trait_def::TraitDef;
91 pub use self::query::queries;
103 pub mod inhabitedness;
120 mod structural_impls;
125 /// The complete set of all analyses described in this module. This is
126 /// produced by the driver and fed to codegen and later passes.
128 /// N.B., these contents are being migrated into queries using the
129 /// *on-demand* infrastructure.
131 pub struct CrateAnalysis {
132 pub access_levels: Lrc<AccessLevels>,
134 pub glob_map: Option<hir::GlobMap>,
138 pub struct Resolutions {
139 pub freevars: FreevarMap,
140 pub trait_map: TraitMap,
141 pub maybe_unused_trait_imports: NodeSet,
142 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
143 pub export_map: ExportMap,
144 /// Extern prelude entries. The value is `true` if the entry was introduced
145 /// via `extern crate` item and not `--extern` option or compiler built-in.
146 pub extern_prelude: FxHashMap<Name, bool>,
149 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
150 pub enum AssociatedItemContainer {
151 TraitContainer(DefId),
152 ImplContainer(DefId),
155 impl AssociatedItemContainer {
156 /// Asserts that this is the def-id of an associated item declared
157 /// in a trait, and returns the trait def-id.
158 pub fn assert_trait(&self) -> DefId {
160 TraitContainer(id) => id,
161 _ => bug!("associated item has wrong container type: {:?}", self)
165 pub fn id(&self) -> DefId {
167 TraitContainer(id) => id,
168 ImplContainer(id) => id,
173 /// The "header" of an impl is everything outside the body: a Self type, a trait
174 /// ref (in the case of a trait impl), and a set of predicates (from the
175 /// bounds/where clauses).
176 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
177 pub struct ImplHeader<'tcx> {
178 pub impl_def_id: DefId,
179 pub self_ty: Ty<'tcx>,
180 pub trait_ref: Option<TraitRef<'tcx>>,
181 pub predicates: Vec<Predicate<'tcx>>,
184 #[derive(Copy, Clone, Debug, PartialEq)]
185 pub struct AssociatedItem {
188 pub kind: AssociatedKind,
190 pub defaultness: hir::Defaultness,
191 pub container: AssociatedItemContainer,
193 /// Whether this is a method with an explicit self
194 /// as its first argument, allowing method calls.
195 pub method_has_self_argument: bool,
198 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash, RustcEncodable, RustcDecodable)]
199 pub enum AssociatedKind {
206 impl AssociatedItem {
207 pub fn def(&self) -> Def {
209 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
210 AssociatedKind::Method => Def::Method(self.def_id),
211 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
212 AssociatedKind::Existential => Def::AssociatedExistential(self.def_id),
216 /// Tests whether the associated item admits a non-trivial implementation
218 pub fn relevant_for_never<'tcx>(&self) -> bool {
220 AssociatedKind::Existential |
221 AssociatedKind::Const |
222 AssociatedKind::Type => true,
223 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
224 AssociatedKind::Method => !self.method_has_self_argument,
228 pub fn signature<'a, 'tcx>(&self, tcx: &TyCtxt<'a, 'tcx, 'tcx>) -> String {
230 ty::AssociatedKind::Method => {
231 // We skip the binder here because the binder would deanonymize all
232 // late-bound regions, and we don't want method signatures to show up
233 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
234 // regions just fine, showing `fn(&MyType)`.
235 tcx.fn_sig(self.def_id).skip_binder().to_string()
237 ty::AssociatedKind::Type => format!("type {};", self.ident),
238 ty::AssociatedKind::Existential => format!("existential type {};", self.ident),
239 ty::AssociatedKind::Const => {
240 format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id))
246 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
247 pub enum Visibility {
248 /// Visible everywhere (including in other crates).
250 /// Visible only in the given crate-local module.
252 /// Not visible anywhere in the local crate. This is the visibility of private external items.
256 pub trait DefIdTree: Copy {
257 fn parent(self, id: DefId) -> Option<DefId>;
259 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
260 if descendant.krate != ancestor.krate {
264 while descendant != ancestor {
265 match self.parent(descendant) {
266 Some(parent) => descendant = parent,
267 None => return false,
274 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
275 fn parent(self, id: DefId) -> Option<DefId> {
276 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
281 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt<'_, '_, '_>) -> Self {
282 match visibility.node {
283 hir::VisibilityKind::Public => Visibility::Public,
284 hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
285 hir::VisibilityKind::Restricted { ref path, .. } => match path.def {
286 // If there is no resolution, `resolve` will have already reported an error, so
287 // assume that the visibility is public to avoid reporting more privacy errors.
288 Def::Err => Visibility::Public,
289 def => Visibility::Restricted(def.def_id()),
291 hir::VisibilityKind::Inherited => {
292 Visibility::Restricted(tcx.hir().get_module_parent(id))
297 /// Returns `true` if an item with this visibility is accessible from the given block.
298 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
299 let restriction = match self {
300 // Public items are visible everywhere.
301 Visibility::Public => return true,
302 // Private items from other crates are visible nowhere.
303 Visibility::Invisible => return false,
304 // Restricted items are visible in an arbitrary local module.
305 Visibility::Restricted(other) if other.krate != module.krate => return false,
306 Visibility::Restricted(module) => module,
309 tree.is_descendant_of(module, restriction)
312 /// Returns `true` if this visibility is at least as accessible as the given visibility
313 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
314 let vis_restriction = match vis {
315 Visibility::Public => return self == Visibility::Public,
316 Visibility::Invisible => return true,
317 Visibility::Restricted(module) => module,
320 self.is_accessible_from(vis_restriction, tree)
323 // Returns `true` if this item is visible anywhere in the local crate.
324 pub fn is_visible_locally(self) -> bool {
326 Visibility::Public => true,
327 Visibility::Restricted(def_id) => def_id.is_local(),
328 Visibility::Invisible => false,
333 #[derive(Copy, Clone, PartialEq, Eq, RustcDecodable, RustcEncodable, Hash)]
335 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
336 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
337 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
338 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
341 /// The crate variances map is computed during typeck and contains the
342 /// variance of every item in the local crate. You should not use it
343 /// directly, because to do so will make your pass dependent on the
344 /// HIR of every item in the local crate. Instead, use
345 /// `tcx.variances_of()` to get the variance for a *particular*
347 pub struct CrateVariancesMap {
348 /// For each item with generics, maps to a vector of the variance
349 /// of its generics. If an item has no generics, it will have no
351 pub variances: FxHashMap<DefId, Lrc<Vec<ty::Variance>>>,
353 /// An empty vector, useful for cloning.
354 pub empty_variance: Lrc<Vec<ty::Variance>>,
358 /// `a.xform(b)` combines the variance of a context with the
359 /// variance of a type with the following meaning. If we are in a
360 /// context with variance `a`, and we encounter a type argument in
361 /// a position with variance `b`, then `a.xform(b)` is the new
362 /// variance with which the argument appears.
368 /// Here, the "ambient" variance starts as covariant. `*mut T` is
369 /// invariant with respect to `T`, so the variance in which the
370 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
371 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
372 /// respect to its type argument `T`, and hence the variance of
373 /// the `i32` here is `Invariant.xform(Covariant)`, which results
374 /// (again) in `Invariant`.
378 /// fn(*const Vec<i32>, *mut Vec<i32)
380 /// The ambient variance is covariant. A `fn` type is
381 /// contravariant with respect to its parameters, so the variance
382 /// within which both pointer types appear is
383 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
384 /// T` is covariant with respect to `T`, so the variance within
385 /// which the first `Vec<i32>` appears is
386 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
387 /// is true for its `i32` argument. In the `*mut T` case, the
388 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
389 /// and hence the outermost type is `Invariant` with respect to
390 /// `Vec<i32>` (and its `i32` argument).
392 /// Source: Figure 1 of "Taming the Wildcards:
393 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
394 pub fn xform(self, v: ty::Variance) -> ty::Variance {
396 // Figure 1, column 1.
397 (ty::Covariant, ty::Covariant) => ty::Covariant,
398 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
399 (ty::Covariant, ty::Invariant) => ty::Invariant,
400 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
402 // Figure 1, column 2.
403 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
404 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
405 (ty::Contravariant, ty::Invariant) => ty::Invariant,
406 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
408 // Figure 1, column 3.
409 (ty::Invariant, _) => ty::Invariant,
411 // Figure 1, column 4.
412 (ty::Bivariant, _) => ty::Bivariant,
417 // Contains information needed to resolve types and (in the future) look up
418 // the types of AST nodes.
419 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
420 pub struct CReaderCacheKey {
425 // Flags that we track on types. These flags are propagated upwards
426 // through the type during type construction, so that we can quickly
427 // check whether the type has various kinds of types in it without
428 // recursing over the type itself.
430 pub struct TypeFlags: u32 {
431 const HAS_PARAMS = 1 << 0;
432 const HAS_SELF = 1 << 1;
433 const HAS_TY_INFER = 1 << 2;
434 const HAS_RE_INFER = 1 << 3;
435 const HAS_RE_PLACEHOLDER = 1 << 4;
437 /// Does this have any `ReEarlyBound` regions? Used to
438 /// determine whether substitition is required, since those
439 /// represent regions that are bound in a `ty::Generics` and
440 /// hence may be substituted.
441 const HAS_RE_EARLY_BOUND = 1 << 5;
443 /// Does this have any region that "appears free" in the type?
444 /// Basically anything but `ReLateBound` and `ReErased`.
445 const HAS_FREE_REGIONS = 1 << 6;
447 /// Is an error type reachable?
448 const HAS_TY_ERR = 1 << 7;
449 const HAS_PROJECTION = 1 << 8;
451 // FIXME: Rename this to the actual property since it's used for generators too
452 const HAS_TY_CLOSURE = 1 << 9;
454 // `true` if there are "names" of types and regions and so forth
455 // that are local to a particular fn
456 const HAS_FREE_LOCAL_NAMES = 1 << 10;
458 // Present if the type belongs in a local type context.
459 // Only set for Infer other than Fresh.
460 const KEEP_IN_LOCAL_TCX = 1 << 11;
462 // Is there a projection that does not involve a bound region?
463 // Currently we can't normalize projections w/ bound regions.
464 const HAS_NORMALIZABLE_PROJECTION = 1 << 12;
466 /// Does this have any `ReLateBound` regions? Used to check
467 /// if a global bound is safe to evaluate.
468 const HAS_RE_LATE_BOUND = 1 << 13;
470 const HAS_TY_PLACEHOLDER = 1 << 14;
472 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
473 TypeFlags::HAS_SELF.bits |
474 TypeFlags::HAS_RE_EARLY_BOUND.bits;
476 // Flags representing the nominal content of a type,
477 // computed by FlagsComputation. If you add a new nominal
478 // flag, it should be added here too.
479 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
480 TypeFlags::HAS_SELF.bits |
481 TypeFlags::HAS_TY_INFER.bits |
482 TypeFlags::HAS_RE_INFER.bits |
483 TypeFlags::HAS_RE_PLACEHOLDER.bits |
484 TypeFlags::HAS_RE_EARLY_BOUND.bits |
485 TypeFlags::HAS_FREE_REGIONS.bits |
486 TypeFlags::HAS_TY_ERR.bits |
487 TypeFlags::HAS_PROJECTION.bits |
488 TypeFlags::HAS_TY_CLOSURE.bits |
489 TypeFlags::HAS_FREE_LOCAL_NAMES.bits |
490 TypeFlags::KEEP_IN_LOCAL_TCX.bits |
491 TypeFlags::HAS_RE_LATE_BOUND.bits |
492 TypeFlags::HAS_TY_PLACEHOLDER.bits;
496 pub struct TyS<'tcx> {
497 pub sty: TyKind<'tcx>,
498 pub flags: TypeFlags,
500 /// This is a kind of confusing thing: it stores the smallest
503 /// (a) the binder itself captures nothing but
504 /// (b) all the late-bound things within the type are captured
505 /// by some sub-binder.
507 /// So, for a type without any late-bound things, like `u32`, this
508 /// will be *innermost*, because that is the innermost binder that
509 /// captures nothing. But for a type `&'D u32`, where `'D` is a
510 /// late-bound region with debruijn index `D`, this would be `D + 1`
511 /// -- the binder itself does not capture `D`, but `D` is captured
512 /// by an inner binder.
514 /// We call this concept an "exclusive" binder `D` because all
515 /// debruijn indices within the type are contained within `0..D`
517 outer_exclusive_binder: ty::DebruijnIndex,
520 // `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
521 #[cfg(target_arch = "x86_64")]
522 static_assert!(MEM_SIZE_OF_TY_S: ::std::mem::size_of::<TyS<'_>>() == 32);
524 impl<'tcx> Ord for TyS<'tcx> {
525 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
526 self.sty.cmp(&other.sty)
530 impl<'tcx> PartialOrd for TyS<'tcx> {
531 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
532 Some(self.sty.cmp(&other.sty))
536 impl<'tcx> PartialEq for TyS<'tcx> {
538 fn eq(&self, other: &TyS<'tcx>) -> bool {
542 impl<'tcx> Eq for TyS<'tcx> {}
544 impl<'tcx> Hash for TyS<'tcx> {
545 fn hash<H: Hasher>(&self, s: &mut H) {
546 (self as *const TyS<'_>).hash(s)
550 impl<'tcx> TyS<'tcx> {
551 pub fn is_primitive_ty(&self) -> bool {
558 TyKind::Infer(InferTy::IntVar(_)) |
559 TyKind::Infer(InferTy::FloatVar(_)) |
560 TyKind::Infer(InferTy::FreshIntTy(_)) |
561 TyKind::Infer(InferTy::FreshFloatTy(_)) => true,
562 TyKind::Ref(_, x, _) => x.is_primitive_ty(),
567 pub fn is_suggestable(&self) -> bool {
572 TyKind::Dynamic(..) |
573 TyKind::Closure(..) |
575 TyKind::Projection(..) => false,
581 impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for ty::TyS<'gcx> {
582 fn hash_stable<W: StableHasherResult>(&self,
583 hcx: &mut StableHashingContext<'a>,
584 hasher: &mut StableHasher<W>) {
588 // The other fields just provide fast access to information that is
589 // also contained in `sty`, so no need to hash them.
592 outer_exclusive_binder: _,
595 sty.hash_stable(hcx, hasher);
599 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
601 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
602 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
604 pub type CanonicalTy<'gcx> = Canonical<'gcx, Ty<'gcx>>;
607 /// A dummy type used to force List to by unsized without requiring fat pointers
608 type OpaqueListContents;
611 /// A wrapper for slices with the additional invariant
612 /// that the slice is interned and no other slice with
613 /// the same contents can exist in the same context.
614 /// This means we can use pointer for both
615 /// equality comparisons and hashing.
616 /// Note: `Slice` was already taken by the `Ty`.
621 opaque: OpaqueListContents,
624 unsafe impl<T: Sync> Sync for List<T> {}
626 impl<T: Copy> List<T> {
628 fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx List<T> {
629 assert!(!mem::needs_drop::<T>());
630 assert!(mem::size_of::<T>() != 0);
631 assert!(slice.len() != 0);
633 // Align up the size of the len (usize) field
634 let align = mem::align_of::<T>();
635 let align_mask = align - 1;
636 let offset = mem::size_of::<usize>();
637 let offset = (offset + align_mask) & !align_mask;
639 let size = offset + slice.len() * mem::size_of::<T>();
641 let mem = arena.alloc_raw(
643 cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
645 let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
647 result.len = slice.len();
649 // Write the elements
650 let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
651 arena_slice.copy_from_slice(slice);
658 impl<T: fmt::Debug> fmt::Debug for List<T> {
659 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
664 impl<T: Encodable> Encodable for List<T> {
666 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
671 impl<T> Ord for List<T> where T: Ord {
672 fn cmp(&self, other: &List<T>) -> Ordering {
673 if self == other { Ordering::Equal } else {
674 <[T] as Ord>::cmp(&**self, &**other)
679 impl<T> PartialOrd for List<T> where T: PartialOrd {
680 fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> {
681 if self == other { Some(Ordering::Equal) } else {
682 <[T] as PartialOrd>::partial_cmp(&**self, &**other)
687 impl<T: PartialEq> PartialEq for List<T> {
689 fn eq(&self, other: &List<T>) -> bool {
693 impl<T: Eq> Eq for List<T> {}
695 impl<T> Hash for List<T> {
697 fn hash<H: Hasher>(&self, s: &mut H) {
698 (self as *const List<T>).hash(s)
702 impl<T> Deref for List<T> {
705 fn deref(&self) -> &[T] {
707 slice::from_raw_parts(self.data.as_ptr(), self.len)
712 impl<'a, T> IntoIterator for &'a List<T> {
714 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
716 fn into_iter(self) -> Self::IntoIter {
721 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
725 pub fn empty<'a>() -> &'a List<T> {
726 #[repr(align(64), C)]
727 struct EmptySlice([u8; 64]);
728 static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
729 assert!(mem::align_of::<T>() <= 64);
731 &*(&EMPTY_SLICE as *const _ as *const List<T>)
736 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
737 pub struct UpvarPath {
738 pub hir_id: hir::HirId,
741 /// Upvars do not get their own node-id. Instead, we use the pair of
742 /// the original var id (that is, the root variable that is referenced
743 /// by the upvar) and the id of the closure expression.
744 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
746 pub var_path: UpvarPath,
747 pub closure_expr_id: LocalDefId,
750 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
751 pub enum BorrowKind {
752 /// Data must be immutable and is aliasable.
755 /// Data must be immutable but not aliasable. This kind of borrow
756 /// cannot currently be expressed by the user and is used only in
757 /// implicit closure bindings. It is needed when the closure
758 /// is borrowing or mutating a mutable referent, e.g.:
760 /// let x: &mut isize = ...;
761 /// let y = || *x += 5;
763 /// If we were to try to translate this closure into a more explicit
764 /// form, we'd encounter an error with the code as written:
766 /// struct Env { x: & &mut isize }
767 /// let x: &mut isize = ...;
768 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
769 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
771 /// This is then illegal because you cannot mutate a `&mut` found
772 /// in an aliasable location. To solve, you'd have to translate with
773 /// an `&mut` borrow:
775 /// struct Env { x: & &mut isize }
776 /// let x: &mut isize = ...;
777 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
778 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
780 /// Now the assignment to `**env.x` is legal, but creating a
781 /// mutable pointer to `x` is not because `x` is not mutable. We
782 /// could fix this by declaring `x` as `let mut x`. This is ok in
783 /// user code, if awkward, but extra weird for closures, since the
784 /// borrow is hidden.
786 /// So we introduce a "unique imm" borrow -- the referent is
787 /// immutable, but not aliasable. This solves the problem. For
788 /// simplicity, we don't give users the way to express this
789 /// borrow, it's just used when translating closures.
792 /// Data is mutable and not aliasable.
796 /// Information describing the capture of an upvar. This is computed
797 /// during `typeck`, specifically by `regionck`.
798 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
799 pub enum UpvarCapture<'tcx> {
800 /// Upvar is captured by value. This is always true when the
801 /// closure is labeled `move`, but can also be true in other cases
802 /// depending on inference.
805 /// Upvar is captured by reference.
806 ByRef(UpvarBorrow<'tcx>),
809 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
810 pub struct UpvarBorrow<'tcx> {
811 /// The kind of borrow: by-ref upvars have access to shared
812 /// immutable borrows, which are not part of the normal language
814 pub kind: BorrowKind,
816 /// Region of the resulting reference.
817 pub region: ty::Region<'tcx>,
820 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
822 #[derive(Copy, Clone)]
823 pub struct ClosureUpvar<'tcx> {
829 #[derive(Clone, Copy, PartialEq, Eq)]
830 pub enum IntVarValue {
832 UintType(ast::UintTy),
835 #[derive(Clone, Copy, PartialEq, Eq)]
836 pub struct FloatVarValue(pub ast::FloatTy);
838 impl ty::EarlyBoundRegion {
839 pub fn to_bound_region(&self) -> ty::BoundRegion {
840 ty::BoundRegion::BrNamed(self.def_id, self.name)
843 /// Does this early bound region have a name? Early bound regions normally
844 /// always have names except when using anonymous lifetimes (`'_`).
845 pub fn has_name(&self) -> bool {
846 self.name != keywords::UnderscoreLifetime.name().as_interned_str()
850 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
851 pub enum GenericParamDefKind {
855 object_lifetime_default: ObjectLifetimeDefault,
856 synthetic: Option<hir::SyntheticTyParamKind>,
860 #[derive(Clone, RustcEncodable, RustcDecodable)]
861 pub struct GenericParamDef {
862 pub name: InternedString,
866 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
867 /// on generic parameter `'a`/`T`, asserts data behind the parameter
868 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
869 pub pure_wrt_drop: bool,
871 pub kind: GenericParamDefKind,
874 impl GenericParamDef {
875 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
876 if let GenericParamDefKind::Lifetime = self.kind {
877 ty::EarlyBoundRegion {
883 bug!("cannot convert a non-lifetime parameter def to an early bound region")
887 pub fn to_bound_region(&self) -> ty::BoundRegion {
888 if let GenericParamDefKind::Lifetime = self.kind {
889 self.to_early_bound_region_data().to_bound_region()
891 bug!("cannot convert a non-lifetime parameter def to an early bound region")
897 pub struct GenericParamCount {
898 pub lifetimes: usize,
902 /// Information about the formal type/lifetime parameters associated
903 /// with an item or method. Analogous to `hir::Generics`.
905 /// The ordering of parameters is the same as in `Subst` (excluding child generics):
906 /// `Self` (optionally), `Lifetime` params..., `Type` params...
907 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
908 pub struct Generics {
909 pub parent: Option<DefId>,
910 pub parent_count: usize,
911 pub params: Vec<GenericParamDef>,
913 /// Reverse map to the `index` field of each `GenericParamDef`
914 pub param_def_id_to_index: FxHashMap<DefId, u32>,
917 pub has_late_bound_regions: Option<Span>,
920 impl<'a, 'gcx, 'tcx> Generics {
921 pub fn count(&self) -> usize {
922 self.parent_count + self.params.len()
925 pub fn own_counts(&self) -> GenericParamCount {
926 // We could cache this as a property of `GenericParamCount`, but
927 // the aim is to refactor this away entirely eventually and the
928 // presence of this method will be a constant reminder.
929 let mut own_counts: GenericParamCount = Default::default();
931 for param in &self.params {
933 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
934 GenericParamDefKind::Type { .. } => own_counts.types += 1,
941 pub fn requires_monomorphization(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
942 for param in &self.params {
944 GenericParamDefKind::Type { .. } => return true,
945 GenericParamDefKind::Lifetime => {}
948 if let Some(parent_def_id) = self.parent {
949 let parent = tcx.generics_of(parent_def_id);
950 parent.requires_monomorphization(tcx)
956 pub fn region_param(&'tcx self,
957 param: &EarlyBoundRegion,
958 tcx: TyCtxt<'a, 'gcx, 'tcx>)
959 -> &'tcx GenericParamDef
961 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
962 let param = &self.params[index as usize];
964 ty::GenericParamDefKind::Lifetime => param,
965 _ => bug!("expected lifetime parameter, but found another generic parameter")
968 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
969 .region_param(param, tcx)
973 /// Returns the `GenericParamDef` associated with this `ParamTy`.
974 pub fn type_param(&'tcx self,
976 tcx: TyCtxt<'a, 'gcx, 'tcx>)
977 -> &'tcx GenericParamDef {
978 if let Some(index) = param.idx.checked_sub(self.parent_count as u32) {
979 let param = &self.params[index as usize];
981 ty::GenericParamDefKind::Type {..} => param,
982 _ => bug!("expected type parameter, but found another generic parameter")
985 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
986 .type_param(param, tcx)
991 /// Bounds on generics.
992 #[derive(Clone, Default)]
993 pub struct GenericPredicates<'tcx> {
994 pub parent: Option<DefId>,
995 pub predicates: Vec<(Predicate<'tcx>, Span)>,
998 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
999 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
1001 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
1002 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
1003 -> InstantiatedPredicates<'tcx> {
1004 let mut instantiated = InstantiatedPredicates::empty();
1005 self.instantiate_into(tcx, &mut instantiated, substs);
1009 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
1010 -> InstantiatedPredicates<'tcx> {
1011 InstantiatedPredicates {
1012 predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
1016 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1017 instantiated: &mut InstantiatedPredicates<'tcx>,
1018 substs: &Substs<'tcx>) {
1019 if let Some(def_id) = self.parent {
1020 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
1022 instantiated.predicates.extend(
1023 self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)),
1027 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1028 -> InstantiatedPredicates<'tcx> {
1029 let mut instantiated = InstantiatedPredicates::empty();
1030 self.instantiate_identity_into(tcx, &mut instantiated);
1034 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1035 instantiated: &mut InstantiatedPredicates<'tcx>) {
1036 if let Some(def_id) = self.parent {
1037 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
1039 instantiated.predicates.extend(self.predicates.iter().map(|&(p, _)| p))
1042 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1043 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
1044 -> InstantiatedPredicates<'tcx>
1046 assert_eq!(self.parent, None);
1047 InstantiatedPredicates {
1048 predicates: self.predicates.iter().map(|(pred, _)| {
1049 pred.subst_supertrait(tcx, poly_trait_ref)
1055 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1056 pub enum Predicate<'tcx> {
1057 /// Corresponds to `where Foo: Bar<A,B,C>`. `Foo` here would be
1058 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1059 /// would be the type parameters.
1060 Trait(PolyTraitPredicate<'tcx>),
1063 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1066 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1068 /// where `<T as TraitRef>::Name == X`, approximately.
1069 /// See the `ProjectionPredicate` struct for details.
1070 Projection(PolyProjectionPredicate<'tcx>),
1072 /// no syntax: `T` well-formed
1073 WellFormed(Ty<'tcx>),
1075 /// trait must be object-safe
1078 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
1079 /// for some substitutions `...` and `T` being a closure type.
1080 /// Satisfied (or refuted) once we know the closure's kind.
1081 ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
1084 Subtype(PolySubtypePredicate<'tcx>),
1086 /// Constant initializer must evaluate successfully.
1087 ConstEvaluatable(DefId, &'tcx Substs<'tcx>),
1090 /// The crate outlives map is computed during typeck and contains the
1091 /// outlives of every item in the local crate. You should not use it
1092 /// directly, because to do so will make your pass dependent on the
1093 /// HIR of every item in the local crate. Instead, use
1094 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1096 pub struct CratePredicatesMap<'tcx> {
1097 /// For each struct with outlive bounds, maps to a vector of the
1098 /// predicate of its outlive bounds. If an item has no outlives
1099 /// bounds, it will have no entry.
1100 pub predicates: FxHashMap<DefId, Lrc<Vec<ty::Predicate<'tcx>>>>,
1102 /// An empty vector, useful for cloning.
1103 pub empty_predicate: Lrc<Vec<ty::Predicate<'tcx>>>,
1106 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1107 fn as_ref(&self) -> &Predicate<'tcx> {
1112 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
1113 /// Performs a substitution suitable for going from a
1114 /// poly-trait-ref to supertraits that must hold if that
1115 /// poly-trait-ref holds. This is slightly different from a normal
1116 /// substitution in terms of what happens with bound regions. See
1117 /// lengthy comment below for details.
1118 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1119 trait_ref: &ty::PolyTraitRef<'tcx>)
1120 -> ty::Predicate<'tcx>
1122 // The interaction between HRTB and supertraits is not entirely
1123 // obvious. Let me walk you (and myself) through an example.
1125 // Let's start with an easy case. Consider two traits:
1127 // trait Foo<'a>: Bar<'a,'a> { }
1128 // trait Bar<'b,'c> { }
1130 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
1131 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
1132 // knew that `Foo<'x>` (for any 'x) then we also know that
1133 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1134 // normal substitution.
1136 // In terms of why this is sound, the idea is that whenever there
1137 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1138 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1139 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1142 // Another example to be careful of is this:
1144 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
1145 // trait Bar1<'b,'c> { }
1147 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
1148 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
1149 // reason is similar to the previous example: any impl of
1150 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
1151 // basically we would want to collapse the bound lifetimes from
1152 // the input (`trait_ref`) and the supertraits.
1154 // To achieve this in practice is fairly straightforward. Let's
1155 // consider the more complicated scenario:
1157 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
1158 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
1159 // where both `'x` and `'b` would have a DB index of 1.
1160 // The substitution from the input trait-ref is therefore going to be
1161 // `'a => 'x` (where `'x` has a DB index of 1).
1162 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1163 // early-bound parameter and `'b' is a late-bound parameter with a
1165 // - If we replace `'a` with `'x` from the input, it too will have
1166 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1167 // just as we wanted.
1169 // There is only one catch. If we just apply the substitution `'a
1170 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1171 // adjust the DB index because we substituting into a binder (it
1172 // tries to be so smart...) resulting in `for<'x> for<'b>
1173 // Bar1<'x,'b>` (we have no syntax for this, so use your
1174 // imagination). Basically the 'x will have DB index of 2 and 'b
1175 // will have DB index of 1. Not quite what we want. So we apply
1176 // the substitution to the *contents* of the trait reference,
1177 // rather than the trait reference itself (put another way, the
1178 // substitution code expects equal binding levels in the values
1179 // from the substitution and the value being substituted into, and
1180 // this trick achieves that).
1182 let substs = &trait_ref.skip_binder().substs;
1184 Predicate::Trait(ref binder) =>
1185 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1186 Predicate::Subtype(ref binder) =>
1187 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1188 Predicate::RegionOutlives(ref binder) =>
1189 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1190 Predicate::TypeOutlives(ref binder) =>
1191 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1192 Predicate::Projection(ref binder) =>
1193 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1194 Predicate::WellFormed(data) =>
1195 Predicate::WellFormed(data.subst(tcx, substs)),
1196 Predicate::ObjectSafe(trait_def_id) =>
1197 Predicate::ObjectSafe(trait_def_id),
1198 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1199 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1200 Predicate::ConstEvaluatable(def_id, const_substs) =>
1201 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1206 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1207 pub struct TraitPredicate<'tcx> {
1208 pub trait_ref: TraitRef<'tcx>
1211 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1213 impl<'tcx> TraitPredicate<'tcx> {
1214 pub fn def_id(&self) -> DefId {
1215 self.trait_ref.def_id
1218 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
1219 self.trait_ref.input_types()
1222 pub fn self_ty(&self) -> Ty<'tcx> {
1223 self.trait_ref.self_ty()
1227 impl<'tcx> PolyTraitPredicate<'tcx> {
1228 pub fn def_id(&self) -> DefId {
1229 // ok to skip binder since trait def-id does not care about regions
1230 self.skip_binder().def_id()
1234 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
1235 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A: B`
1236 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1237 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>,
1239 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>,
1241 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1242 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1244 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1245 pub struct SubtypePredicate<'tcx> {
1246 pub a_is_expected: bool,
1250 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1252 /// This kind of predicate has no *direct* correspondent in the
1253 /// syntax, but it roughly corresponds to the syntactic forms:
1255 /// 1. `T: TraitRef<..., Item=Type>`
1256 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1258 /// In particular, form #1 is "desugared" to the combination of a
1259 /// normal trait predicate (`T: TraitRef<...>`) and one of these
1260 /// predicates. Form #2 is a broader form in that it also permits
1261 /// equality between arbitrary types. Processing an instance of
1262 /// Form #2 eventually yields one of these `ProjectionPredicate`
1263 /// instances to normalize the LHS.
1264 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1265 pub struct ProjectionPredicate<'tcx> {
1266 pub projection_ty: ProjectionTy<'tcx>,
1270 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1272 impl<'tcx> PolyProjectionPredicate<'tcx> {
1273 /// Returns the `DefId` of the associated item being projected.
1274 pub fn item_def_id(&self) -> DefId {
1275 self.skip_binder().projection_ty.item_def_id
1279 pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'_, '_, '_>) -> PolyTraitRef<'tcx> {
1280 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
1281 // `self.0.trait_ref` is permitted to have escaping regions.
1282 // This is because here `self` has a `Binder` and so does our
1283 // return value, so we are preserving the number of binding
1285 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1288 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1289 self.map_bound(|predicate| predicate.ty)
1292 /// The `DefId` of the `TraitItem` for the associated type.
1294 /// Note that this is not the `DefId` of the `TraitRef` containing this
1295 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
1296 pub fn projection_def_id(&self) -> DefId {
1297 // okay to skip binder since trait def-id does not care about regions
1298 self.skip_binder().projection_ty.item_def_id
1302 pub trait ToPolyTraitRef<'tcx> {
1303 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1306 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1307 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1308 ty::Binder::dummy(self.clone())
1312 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1313 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1314 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1318 pub trait ToPredicate<'tcx> {
1319 fn to_predicate(&self) -> Predicate<'tcx>;
1322 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1323 fn to_predicate(&self) -> Predicate<'tcx> {
1324 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1325 trait_ref: self.clone()
1330 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1331 fn to_predicate(&self) -> Predicate<'tcx> {
1332 ty::Predicate::Trait(self.to_poly_trait_predicate())
1336 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1337 fn to_predicate(&self) -> Predicate<'tcx> {
1338 Predicate::RegionOutlives(self.clone())
1342 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1343 fn to_predicate(&self) -> Predicate<'tcx> {
1344 Predicate::TypeOutlives(self.clone())
1348 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1349 fn to_predicate(&self) -> Predicate<'tcx> {
1350 Predicate::Projection(self.clone())
1354 // A custom iterator used by Predicate::walk_tys.
1355 enum WalkTysIter<'tcx, I, J, K>
1356 where I: Iterator<Item = Ty<'tcx>>,
1357 J: Iterator<Item = Ty<'tcx>>,
1358 K: Iterator<Item = Ty<'tcx>>
1362 Two(Ty<'tcx>, Ty<'tcx>),
1368 impl<'tcx, I, J, K> Iterator for WalkTysIter<'tcx, I, J, K>
1369 where I: Iterator<Item = Ty<'tcx>>,
1370 J: Iterator<Item = Ty<'tcx>>,
1371 K: Iterator<Item = Ty<'tcx>>
1373 type Item = Ty<'tcx>;
1375 fn next(&mut self) -> Option<Ty<'tcx>> {
1377 WalkTysIter::None => None,
1378 WalkTysIter::One(item) => {
1379 *self = WalkTysIter::None;
1382 WalkTysIter::Two(item1, item2) => {
1383 *self = WalkTysIter::One(item2);
1386 WalkTysIter::Types(ref mut iter) => {
1389 WalkTysIter::InputTypes(ref mut iter) => {
1392 WalkTysIter::ProjectionTypes(ref mut iter) => {
1399 impl<'tcx> Predicate<'tcx> {
1400 /// Iterates over the types in this predicate. Note that in all
1401 /// cases this is skipping over a binder, so late-bound regions
1402 /// with depth 0 are bound by the predicate.
1403 pub fn walk_tys(&'a self) -> impl Iterator<Item = Ty<'tcx>> + 'a {
1405 ty::Predicate::Trait(ref data) => {
1406 WalkTysIter::InputTypes(data.skip_binder().input_types())
1408 ty::Predicate::Subtype(binder) => {
1409 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1410 WalkTysIter::Two(a, b)
1412 ty::Predicate::TypeOutlives(binder) => {
1413 WalkTysIter::One(binder.skip_binder().0)
1415 ty::Predicate::RegionOutlives(..) => {
1418 ty::Predicate::Projection(ref data) => {
1419 let inner = data.skip_binder();
1420 WalkTysIter::ProjectionTypes(
1421 inner.projection_ty.substs.types().chain(Some(inner.ty)))
1423 ty::Predicate::WellFormed(data) => {
1424 WalkTysIter::One(data)
1426 ty::Predicate::ObjectSafe(_trait_def_id) => {
1429 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1430 WalkTysIter::Types(closure_substs.substs.types())
1432 ty::Predicate::ConstEvaluatable(_, substs) => {
1433 WalkTysIter::Types(substs.types())
1438 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1440 Predicate::Trait(ref t) => {
1441 Some(t.to_poly_trait_ref())
1443 Predicate::Projection(..) |
1444 Predicate::Subtype(..) |
1445 Predicate::RegionOutlives(..) |
1446 Predicate::WellFormed(..) |
1447 Predicate::ObjectSafe(..) |
1448 Predicate::ClosureKind(..) |
1449 Predicate::TypeOutlives(..) |
1450 Predicate::ConstEvaluatable(..) => {
1456 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1458 Predicate::TypeOutlives(data) => {
1461 Predicate::Trait(..) |
1462 Predicate::Projection(..) |
1463 Predicate::Subtype(..) |
1464 Predicate::RegionOutlives(..) |
1465 Predicate::WellFormed(..) |
1466 Predicate::ObjectSafe(..) |
1467 Predicate::ClosureKind(..) |
1468 Predicate::ConstEvaluatable(..) => {
1475 /// Represents the bounds declared on a particular set of type
1476 /// parameters. Should eventually be generalized into a flag list of
1477 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1478 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1479 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1480 /// the `GenericPredicates` are expressed in terms of the bound type
1481 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1482 /// represented a set of bounds for some particular instantiation,
1483 /// meaning that the generic parameters have been substituted with
1488 /// struct Foo<T,U:Bar<T>> { ... }
1490 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1491 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1492 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1493 /// [usize:Bar<isize>]]`.
1495 pub struct InstantiatedPredicates<'tcx> {
1496 pub predicates: Vec<Predicate<'tcx>>,
1499 impl<'tcx> InstantiatedPredicates<'tcx> {
1500 pub fn empty() -> InstantiatedPredicates<'tcx> {
1501 InstantiatedPredicates { predicates: vec![] }
1504 pub fn is_empty(&self) -> bool {
1505 self.predicates.is_empty()
1509 /// "Universes" are used during type- and trait-checking in the
1510 /// presence of `for<..>` binders to control what sets of names are
1511 /// visible. Universes are arranged into a tree: the root universe
1512 /// contains names that are always visible. Each child then adds a new
1513 /// set of names that are visible, in addition to those of its parent.
1514 /// We say that the child universe "extends" the parent universe with
1517 /// To make this more concrete, consider this program:
1521 /// fn bar<T>(x: T) {
1522 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1526 /// The struct name `Foo` is in the root universe U0. But the type
1527 /// parameter `T`, introduced on `bar`, is in an extended universe U1
1528 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
1529 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
1530 /// region `'a` is in a universe U2 that extends U1, because we can
1531 /// name it inside the fn type but not outside.
1533 /// Universes are used to do type- and trait-checking around these
1534 /// "forall" binders (also called **universal quantification**). The
1535 /// idea is that when, in the body of `bar`, we refer to `T` as a
1536 /// type, we aren't referring to any type in particular, but rather a
1537 /// kind of "fresh" type that is distinct from all other types we have
1538 /// actually declared. This is called a **placeholder** type, and we
1539 /// use universes to talk about this. In other words, a type name in
1540 /// universe 0 always corresponds to some "ground" type that the user
1541 /// declared, but a type name in a non-zero universe is a placeholder
1542 /// type -- an idealized representative of "types in general" that we
1543 /// use for checking generic functions.
1545 pub struct UniverseIndex {
1546 DEBUG_FORMAT = "U{}",
1550 impl_stable_hash_for!(struct UniverseIndex { private });
1552 impl UniverseIndex {
1553 pub const ROOT: UniverseIndex = UniverseIndex::from_u32_const(0);
1555 /// Returns the "next" universe index in order -- this new index
1556 /// is considered to extend all previous universes. This
1557 /// corresponds to entering a `forall` quantifier. So, for
1558 /// example, suppose we have this type in universe `U`:
1561 /// for<'a> fn(&'a u32)
1564 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1565 /// new universe that extends `U` -- in this new universe, we can
1566 /// name the region `'a`, but that region was not nameable from
1567 /// `U` because it was not in scope there.
1568 pub fn next_universe(self) -> UniverseIndex {
1569 UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
1572 /// Returns `true` if `self` can name a name from `other` -- in other words,
1573 /// if the set of names in `self` is a superset of those in
1574 /// `other` (`self >= other`).
1575 pub fn can_name(self, other: UniverseIndex) -> bool {
1576 self.private >= other.private
1579 /// Returns `true` if `self` cannot name some names from `other` -- in other
1580 /// words, if the set of names in `self` is a strict subset of
1581 /// those in `other` (`self < other`).
1582 pub fn cannot_name(self, other: UniverseIndex) -> bool {
1583 self.private < other.private
1587 /// The "placeholder index" fully defines a placeholder region.
1588 /// Placeholder regions are identified by both a **universe** as well
1589 /// as a "bound-region" within that universe. The `bound_region` is
1590 /// basically a name -- distinct bound regions within the same
1591 /// universe are just two regions with an unknown relationship to one
1593 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
1594 pub struct Placeholder<T> {
1595 pub universe: UniverseIndex,
1599 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for Placeholder<T>
1600 where T: HashStable<StableHashingContext<'a>>
1602 fn hash_stable<W: StableHasherResult>(
1604 hcx: &mut StableHashingContext<'a>,
1605 hasher: &mut StableHasher<W>
1607 self.universe.hash_stable(hcx, hasher);
1608 self.name.hash_stable(hcx, hasher);
1612 pub type PlaceholderRegion = Placeholder<BoundRegion>;
1614 pub type PlaceholderType = Placeholder<BoundVar>;
1616 /// When type checking, we use the `ParamEnv` to track
1617 /// details about the set of where-clauses that are in scope at this
1618 /// particular point.
1619 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1620 pub struct ParamEnv<'tcx> {
1621 /// Obligations that the caller must satisfy. This is basically
1622 /// the set of bounds on the in-scope type parameters, translated
1623 /// into Obligations, and elaborated and normalized.
1624 pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1626 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1627 /// want `Reveal::All` -- note that this is always paired with an
1628 /// empty environment. To get that, use `ParamEnv::reveal()`.
1629 pub reveal: traits::Reveal,
1632 impl<'tcx> ParamEnv<'tcx> {
1633 /// Construct a trait environment suitable for contexts where
1634 /// there are no where clauses in scope. Hidden types (like `impl
1635 /// Trait`) are left hidden, so this is suitable for ordinary
1638 pub fn empty() -> Self {
1639 Self::new(List::empty(), Reveal::UserFacing)
1642 /// Construct a trait environment with no where clauses in scope
1643 /// where the values of all `impl Trait` and other hidden types
1644 /// are revealed. This is suitable for monomorphized, post-typeck
1645 /// environments like codegen or doing optimizations.
1647 /// N.B. If you want to have predicates in scope, use `ParamEnv::new`,
1648 /// or invoke `param_env.with_reveal_all()`.
1650 pub fn reveal_all() -> Self {
1651 Self::new(List::empty(), Reveal::All)
1654 /// Construct a trait environment with the given set of predicates.
1656 pub fn new(caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1659 ty::ParamEnv { caller_bounds, reveal }
1662 /// Returns a new parameter environment with the same clauses, but
1663 /// which "reveals" the true results of projections in all cases
1664 /// (even for associated types that are specializable). This is
1665 /// the desired behavior during codegen and certain other special
1666 /// contexts; normally though we want to use `Reveal::UserFacing`,
1667 /// which is the default.
1668 pub fn with_reveal_all(self) -> Self {
1669 ty::ParamEnv { reveal: Reveal::All, ..self }
1672 /// Returns this same environment but with no caller bounds.
1673 pub fn without_caller_bounds(self) -> Self {
1674 ty::ParamEnv { caller_bounds: List::empty(), ..self }
1677 /// Creates a suitable environment in which to perform trait
1678 /// queries on the given value. When type-checking, this is simply
1679 /// the pair of the environment plus value. But when reveal is set to
1680 /// All, then if `value` does not reference any type parameters, we will
1681 /// pair it with the empty environment. This improves caching and is generally
1684 /// N.B., we preserve the environment when type-checking because it
1685 /// is possible for the user to have wacky where-clauses like
1686 /// `where Box<u32>: Copy`, which are clearly never
1687 /// satisfiable. We generally want to behave as if they were true,
1688 /// although the surrounding function is never reachable.
1689 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1691 Reveal::UserFacing => {
1699 if value.has_placeholders()
1700 || value.needs_infer()
1701 || value.has_param_types()
1702 || value.has_self_ty()
1710 param_env: self.without_caller_bounds(),
1719 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1720 pub struct ParamEnvAnd<'tcx, T> {
1721 pub param_env: ParamEnv<'tcx>,
1725 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1726 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1727 (self.param_env, self.value)
1731 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'gcx, T>
1732 where T: HashStable<StableHashingContext<'a>>
1734 fn hash_stable<W: StableHasherResult>(&self,
1735 hcx: &mut StableHashingContext<'a>,
1736 hasher: &mut StableHasher<W>) {
1742 param_env.hash_stable(hcx, hasher);
1743 value.hash_stable(hcx, hasher);
1747 #[derive(Copy, Clone, Debug)]
1748 pub struct Destructor {
1749 /// The def-id of the destructor method
1754 pub struct AdtFlags: u32 {
1755 const NO_ADT_FLAGS = 0;
1756 const IS_ENUM = 1 << 0;
1757 const IS_UNION = 1 << 1;
1758 const IS_STRUCT = 1 << 2;
1759 const HAS_CTOR = 1 << 3;
1760 const IS_PHANTOM_DATA = 1 << 4;
1761 const IS_FUNDAMENTAL = 1 << 5;
1762 const IS_BOX = 1 << 6;
1763 /// Indicates whether the type is an `Arc`.
1764 const IS_ARC = 1 << 7;
1765 /// Indicates whether the type is an `Rc`.
1766 const IS_RC = 1 << 8;
1767 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1768 /// (i.e., this flag is never set unless this ADT is an enum).
1769 const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 9;
1774 pub struct VariantFlags: u32 {
1775 const NO_VARIANT_FLAGS = 0;
1776 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1777 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1782 pub struct VariantDef {
1783 /// The variant's `DefId`. If this is a tuple-like struct,
1784 /// this is the `DefId` of the struct's ctor.
1786 pub name: Name, // struct's name if this is a struct
1787 pub discr: VariantDiscr,
1788 pub fields: Vec<FieldDef>,
1789 pub ctor_kind: CtorKind,
1790 flags: VariantFlags,
1793 impl<'a, 'gcx, 'tcx> VariantDef {
1794 /// Create a new `VariantDef`.
1796 /// - `did` is the DefId used for the variant - for tuple-structs, it is the constructor DefId,
1797 /// and for everything else, it is the variant DefId.
1798 /// - `attribute_def_id` is the DefId that has the variant's attributes.
1799 /// this is the struct DefId for structs, and the variant DefId for variants.
1801 /// Note that we *could* use the constructor DefId, because the constructor attributes
1802 /// redirect to the base attributes, but compiling a small crate requires
1803 /// loading the AdtDefs for all the structs in the universe (e.g., coherence for any
1804 /// built-in trait), and we do not want to load attributes twice.
1806 /// If someone speeds up attribute loading to not be a performance concern, they can
1807 /// remove this hack and use the constructor DefId everywhere.
1808 pub fn new(tcx: TyCtxt<'a, 'gcx, 'tcx>,
1811 discr: VariantDiscr,
1812 fields: Vec<FieldDef>,
1814 ctor_kind: CtorKind,
1815 attribute_def_id: DefId)
1818 debug!("VariantDef::new({:?}, {:?}, {:?}, {:?}, {:?}, {:?}, {:?})", did, name, discr,
1819 fields, adt_kind, ctor_kind, attribute_def_id);
1820 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1821 if adt_kind == AdtKind::Struct && tcx.has_attr(attribute_def_id, "non_exhaustive") {
1822 debug!("found non-exhaustive field list for {:?}", did);
1823 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1836 pub fn is_field_list_non_exhaustive(&self) -> bool {
1837 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1841 impl_stable_hash_for!(struct VariantDef {
1850 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1851 pub enum VariantDiscr {
1852 /// Explicit value for this variant, i.e., `X = 123`.
1853 /// The `DefId` corresponds to the embedded constant.
1856 /// The previous variant's discriminant plus one.
1857 /// For efficiency reasons, the distance from the
1858 /// last `Explicit` discriminant is being stored,
1859 /// or `0` for the first variant, if it has none.
1864 pub struct FieldDef {
1867 pub vis: Visibility,
1870 /// The definition of an abstract data type -- a struct or enum.
1872 /// These are all interned (by `intern_adt_def`) into the `adt_defs`
1876 pub variants: IndexVec<self::layout::VariantIdx, VariantDef>,
1878 pub repr: ReprOptions,
1881 impl PartialOrd for AdtDef {
1882 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1883 Some(self.cmp(&other))
1887 /// There should be only one AdtDef for each `did`, therefore
1888 /// it is fine to implement `Ord` only based on `did`.
1889 impl Ord for AdtDef {
1890 fn cmp(&self, other: &AdtDef) -> Ordering {
1891 self.did.cmp(&other.did)
1895 impl PartialEq for AdtDef {
1896 // AdtDef are always interned and this is part of TyS equality
1898 fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) }
1901 impl Eq for AdtDef {}
1903 impl Hash for AdtDef {
1905 fn hash<H: Hasher>(&self, s: &mut H) {
1906 (self as *const AdtDef).hash(s)
1910 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1911 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1916 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1919 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1920 fn hash_stable<W: StableHasherResult>(&self,
1921 hcx: &mut StableHashingContext<'a>,
1922 hasher: &mut StableHasher<W>) {
1924 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> = Default::default();
1927 let hash: Fingerprint = CACHE.with(|cache| {
1928 let addr = self as *const AdtDef as usize;
1929 *cache.borrow_mut().entry(addr).or_insert_with(|| {
1937 let mut hasher = StableHasher::new();
1938 did.hash_stable(hcx, &mut hasher);
1939 variants.hash_stable(hcx, &mut hasher);
1940 flags.hash_stable(hcx, &mut hasher);
1941 repr.hash_stable(hcx, &mut hasher);
1947 hash.hash_stable(hcx, hasher);
1951 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
1952 pub enum AdtKind { Struct, Union, Enum }
1954 impl Into<DataTypeKind> for AdtKind {
1955 fn into(self) -> DataTypeKind {
1957 AdtKind::Struct => DataTypeKind::Struct,
1958 AdtKind::Union => DataTypeKind::Union,
1959 AdtKind::Enum => DataTypeKind::Enum,
1965 #[derive(RustcEncodable, RustcDecodable, Default)]
1966 pub struct ReprFlags: u8 {
1967 const IS_C = 1 << 0;
1968 const IS_SIMD = 1 << 1;
1969 const IS_TRANSPARENT = 1 << 2;
1970 // Internal only for now. If true, don't reorder fields.
1971 const IS_LINEAR = 1 << 3;
1973 // Any of these flags being set prevent field reordering optimisation.
1974 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1975 ReprFlags::IS_SIMD.bits |
1976 ReprFlags::IS_LINEAR.bits;
1980 impl_stable_hash_for!(struct ReprFlags {
1986 /// Represents the repr options provided by the user,
1987 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1988 pub struct ReprOptions {
1989 pub int: Option<attr::IntType>,
1992 pub flags: ReprFlags,
1995 impl_stable_hash_for!(struct ReprOptions {
2003 pub fn new(tcx: TyCtxt<'_, '_, '_>, did: DefId) -> ReprOptions {
2004 let mut flags = ReprFlags::empty();
2005 let mut size = None;
2006 let mut max_align = 0;
2007 let mut min_pack = 0;
2008 for attr in tcx.get_attrs(did).iter() {
2009 for r in attr::find_repr_attrs(&tcx.sess.parse_sess, attr) {
2010 flags.insert(match r {
2011 attr::ReprC => ReprFlags::IS_C,
2012 attr::ReprPacked(pack) => {
2013 min_pack = if min_pack > 0 {
2014 cmp::min(pack, min_pack)
2020 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
2021 attr::ReprSimd => ReprFlags::IS_SIMD,
2022 attr::ReprInt(i) => {
2026 attr::ReprAlign(align) => {
2027 max_align = cmp::max(align, max_align);
2034 // This is here instead of layout because the choice must make it into metadata.
2035 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
2036 flags.insert(ReprFlags::IS_LINEAR);
2038 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
2042 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
2044 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
2046 pub fn packed(&self) -> bool { self.pack > 0 }
2048 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
2050 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
2052 pub fn discr_type(&self) -> attr::IntType {
2053 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
2056 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
2057 /// layout" optimizations, such as representing `Foo<&T>` as a
2059 pub fn inhibit_enum_layout_opt(&self) -> bool {
2060 self.c() || self.int.is_some()
2063 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
2064 /// optimizations, such as with repr(C) or repr(packed(1)).
2065 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
2066 !(self.flags & ReprFlags::IS_UNOPTIMISABLE).is_empty() || (self.pack == 1)
2069 /// Returns true if this `#[repr()]` should inhibit union abi optimisations
2070 pub fn inhibit_union_abi_opt(&self) -> bool {
2076 impl<'a, 'gcx, 'tcx> AdtDef {
2077 fn new(tcx: TyCtxt<'_, '_, '_>,
2080 variants: IndexVec<VariantIdx, VariantDef>,
2081 repr: ReprOptions) -> Self {
2082 debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
2083 let mut flags = AdtFlags::NO_ADT_FLAGS;
2085 if kind == AdtKind::Enum && tcx.has_attr(did, "non_exhaustive") {
2086 debug!("found non-exhaustive variant list for {:?}", did);
2087 flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
2089 flags |= match kind {
2090 AdtKind::Enum => AdtFlags::IS_ENUM,
2091 AdtKind::Union => AdtFlags::IS_UNION,
2092 AdtKind::Struct => AdtFlags::IS_STRUCT,
2095 if let AdtKind::Struct = kind {
2096 let variant_def = &variants[VariantIdx::new(0)];
2097 let def_key = tcx.def_key(variant_def.did);
2098 match def_key.disambiguated_data.data {
2099 DefPathData::StructCtor => flags |= AdtFlags::HAS_CTOR,
2104 let attrs = tcx.get_attrs(did);
2105 if attr::contains_name(&attrs, "fundamental") {
2106 flags |= AdtFlags::IS_FUNDAMENTAL;
2108 if Some(did) == tcx.lang_items().phantom_data() {
2109 flags |= AdtFlags::IS_PHANTOM_DATA;
2111 if Some(did) == tcx.lang_items().owned_box() {
2112 flags |= AdtFlags::IS_BOX;
2114 if Some(did) == tcx.lang_items().arc() {
2115 flags |= AdtFlags::IS_ARC;
2117 if Some(did) == tcx.lang_items().rc() {
2118 flags |= AdtFlags::IS_RC;
2130 pub fn is_struct(&self) -> bool {
2131 self.flags.contains(AdtFlags::IS_STRUCT)
2135 pub fn is_union(&self) -> bool {
2136 self.flags.contains(AdtFlags::IS_UNION)
2140 pub fn is_enum(&self) -> bool {
2141 self.flags.contains(AdtFlags::IS_ENUM)
2145 pub fn is_variant_list_non_exhaustive(&self) -> bool {
2146 self.flags.contains(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
2149 /// Returns the kind of the ADT.
2151 pub fn adt_kind(&self) -> AdtKind {
2154 } else if self.is_union() {
2161 pub fn descr(&self) -> &'static str {
2162 match self.adt_kind() {
2163 AdtKind::Struct => "struct",
2164 AdtKind::Union => "union",
2165 AdtKind::Enum => "enum",
2170 pub fn variant_descr(&self) -> &'static str {
2171 match self.adt_kind() {
2172 AdtKind::Struct => "struct",
2173 AdtKind::Union => "union",
2174 AdtKind::Enum => "variant",
2178 /// If this function returns `true`, it implies that `is_struct` must return `true`.
2180 pub fn has_ctor(&self) -> bool {
2181 self.flags.contains(AdtFlags::HAS_CTOR)
2184 /// Returns whether this type is `#[fundamental]` for the purposes
2185 /// of coherence checking.
2187 pub fn is_fundamental(&self) -> bool {
2188 self.flags.contains(AdtFlags::IS_FUNDAMENTAL)
2191 /// Returns `true` if this is PhantomData<T>.
2193 pub fn is_phantom_data(&self) -> bool {
2194 self.flags.contains(AdtFlags::IS_PHANTOM_DATA)
2197 /// Returns `true` if this is `Arc<T>`.
2198 pub fn is_arc(&self) -> bool {
2199 self.flags.contains(AdtFlags::IS_ARC)
2202 /// Returns `true` if this is `Rc<T>`.
2203 pub fn is_rc(&self) -> bool {
2204 self.flags.contains(AdtFlags::IS_RC)
2207 /// Returns `true` if this is Box<T>.
2209 pub fn is_box(&self) -> bool {
2210 self.flags.contains(AdtFlags::IS_BOX)
2213 /// Returns whether this type has a destructor.
2214 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
2215 self.destructor(tcx).is_some()
2218 /// Asserts this is a struct or union and returns its unique variant.
2219 pub fn non_enum_variant(&self) -> &VariantDef {
2220 assert!(self.is_struct() || self.is_union());
2221 &self.variants[VariantIdx::new(0)]
2225 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Lrc<GenericPredicates<'gcx>> {
2226 tcx.predicates_of(self.did)
2229 /// Returns an iterator over all fields contained
2232 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
2233 self.variants.iter().flat_map(|v| v.fields.iter())
2236 pub fn is_payloadfree(&self) -> bool {
2237 !self.variants.is_empty() &&
2238 self.variants.iter().all(|v| v.fields.is_empty())
2241 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
2244 .find(|v| v.did == vid)
2245 .expect("variant_with_id: unknown variant")
2248 pub fn variant_index_with_id(&self, vid: DefId) -> VariantIdx {
2251 .find(|(_, v)| v.did == vid)
2252 .expect("variant_index_with_id: unknown variant")
2256 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
2258 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
2259 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
2260 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) |
2261 Def::SelfCtor(..) => self.non_enum_variant(),
2262 _ => bug!("unexpected def {:?} in variant_of_def", def)
2267 pub fn eval_explicit_discr(
2269 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2271 ) -> Option<Discr<'tcx>> {
2272 let param_env = ParamEnv::empty();
2273 let repr_type = self.repr.discr_type();
2274 let substs = Substs::identity_for_item(tcx.global_tcx(), expr_did);
2275 let instance = ty::Instance::new(expr_did, substs);
2276 let cid = GlobalId {
2280 match tcx.const_eval(param_env.and(cid)) {
2282 // FIXME: Find the right type and use it instead of `val.ty` here
2283 if let Some(b) = val.assert_bits(tcx.global_tcx(), param_env.and(val.ty)) {
2284 trace!("discriminants: {} ({:?})", b, repr_type);
2290 info!("invalid enum discriminant: {:#?}", val);
2291 ::mir::interpret::struct_error(
2292 tcx.at(tcx.def_span(expr_did)),
2293 "constant evaluation of enum discriminant resulted in non-integer",
2298 Err(ErrorHandled::Reported) => {
2299 if !expr_did.is_local() {
2300 span_bug!(tcx.def_span(expr_did),
2301 "variant discriminant evaluation succeeded \
2302 in its crate but failed locally");
2306 Err(ErrorHandled::TooGeneric) => span_bug!(
2307 tcx.def_span(expr_did),
2308 "enum discriminant depends on generic arguments",
2314 pub fn discriminants(
2316 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2317 ) -> impl Iterator<Item=(VariantIdx, Discr<'tcx>)> + Captures<'gcx> + 'a {
2318 let repr_type = self.repr.discr_type();
2319 let initial = repr_type.initial_discriminant(tcx.global_tcx());
2320 let mut prev_discr = None::<Discr<'tcx>>;
2321 self.variants.iter_enumerated().map(move |(i, v)| {
2322 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
2323 if let VariantDiscr::Explicit(expr_did) = v.discr {
2324 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
2328 prev_discr = Some(discr);
2334 /// Compute the discriminant value used by a specific variant.
2335 /// Unlike `discriminants`, this is (amortized) constant-time,
2336 /// only doing at most one query for evaluating an explicit
2337 /// discriminant (the last one before the requested variant),
2338 /// assuming there are no constant-evaluation errors there.
2339 pub fn discriminant_for_variant(&self,
2340 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2341 variant_index: VariantIdx)
2343 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2344 let explicit_value = val
2345 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2346 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx.global_tcx()));
2347 explicit_value.checked_add(tcx, offset as u128).0
2350 /// Yields a DefId for the discriminant and an offset to add to it
2351 /// Alternatively, if there is no explicit discriminant, returns the
2352 /// inferred discriminant directly
2353 pub fn discriminant_def_for_variant(
2355 variant_index: VariantIdx,
2356 ) -> (Option<DefId>, u32) {
2357 let mut explicit_index = variant_index.as_u32();
2360 match self.variants[VariantIdx::from_u32(explicit_index)].discr {
2361 ty::VariantDiscr::Relative(0) => {
2365 ty::VariantDiscr::Relative(distance) => {
2366 explicit_index -= distance;
2368 ty::VariantDiscr::Explicit(did) => {
2369 expr_did = Some(did);
2374 (expr_did, variant_index.as_u32() - explicit_index)
2377 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
2378 tcx.adt_destructor(self.did)
2381 /// Returns a list of types such that `Self: Sized` if and only
2382 /// if that type is Sized, or `TyErr` if this type is recursive.
2384 /// Oddly enough, checking that the sized-constraint is Sized is
2385 /// actually more expressive than checking all members:
2386 /// the Sized trait is inductive, so an associated type that references
2387 /// Self would prevent its containing ADT from being Sized.
2389 /// Due to normalization being eager, this applies even if
2390 /// the associated type is behind a pointer, e.g., issue #31299.
2391 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
2392 match tcx.try_adt_sized_constraint(DUMMY_SP, self.did) {
2395 debug!("adt_sized_constraint: {:?} is recursive", self);
2396 // This should be reported as an error by `check_representable`.
2398 // Consider the type as Sized in the meanwhile to avoid
2399 // further errors. Delay our `bug` diagnostic here to get
2400 // emitted later as well in case we accidentally otherwise don't
2403 tcx.intern_type_list(&[tcx.types.err])
2408 fn sized_constraint_for_ty(&self,
2409 tcx: TyCtxt<'a, 'tcx, 'tcx>,
2412 let result = match ty.sty {
2413 Bool | Char | Int(..) | Uint(..) | Float(..) |
2414 RawPtr(..) | Ref(..) | FnDef(..) | FnPtr(_) |
2415 Array(..) | Closure(..) | Generator(..) | Never => {
2424 GeneratorWitness(..) => {
2425 // these are never sized - return the target type
2432 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
2436 Adt(adt, substs) => {
2438 let adt_tys = adt.sized_constraint(tcx);
2439 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
2442 .map(|ty| ty.subst(tcx, substs))
2443 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2447 Projection(..) | Opaque(..) => {
2448 // must calculate explicitly.
2449 // FIXME: consider special-casing always-Sized projections
2453 UnnormalizedProjection(..) => bug!("only used with chalk-engine"),
2456 // perf hack: if there is a `T: Sized` bound, then
2457 // we know that `T` is Sized and do not need to check
2460 let sized_trait = match tcx.lang_items().sized_trait() {
2462 _ => return vec![ty]
2464 let sized_predicate = Binder::dummy(TraitRef {
2465 def_id: sized_trait,
2466 substs: tcx.mk_substs_trait(ty, &[])
2468 let predicates = &tcx.predicates_of(self.did).predicates;
2469 if predicates.iter().any(|(p, _)| *p == sized_predicate) {
2479 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2483 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2488 impl<'a, 'gcx, 'tcx> FieldDef {
2489 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
2490 tcx.type_of(self.did).subst(tcx, subst)
2494 /// Represents the various closure traits in the Rust language. This
2495 /// will determine the type of the environment (`self`, in the
2496 /// desugaring) argument that the closure expects.
2498 /// You can get the environment type of a closure using
2499 /// `tcx.closure_env_ty()`.
2500 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
2501 pub enum ClosureKind {
2502 // Warning: Ordering is significant here! The ordering is chosen
2503 // because the trait Fn is a subtrait of FnMut and so in turn, and
2504 // hence we order it so that Fn < FnMut < FnOnce.
2510 impl<'a, 'tcx> ClosureKind {
2511 // This is the initial value used when doing upvar inference.
2512 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2514 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
2516 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
2517 ClosureKind::FnMut => {
2518 tcx.require_lang_item(FnMutTraitLangItem)
2520 ClosureKind::FnOnce => {
2521 tcx.require_lang_item(FnOnceTraitLangItem)
2526 /// Returns `true` if this a type that impls this closure kind
2527 /// must also implement `other`.
2528 pub fn extends(self, other: ty::ClosureKind) -> bool {
2529 match (self, other) {
2530 (ClosureKind::Fn, ClosureKind::Fn) => true,
2531 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2532 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2533 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2534 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2535 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2540 /// Returns the representative scalar type for this closure kind.
2541 /// See `TyS::to_opt_closure_kind` for more details.
2542 pub fn to_ty(self, tcx: TyCtxt<'_, '_, 'tcx>) -> Ty<'tcx> {
2544 ty::ClosureKind::Fn => tcx.types.i8,
2545 ty::ClosureKind::FnMut => tcx.types.i16,
2546 ty::ClosureKind::FnOnce => tcx.types.i32,
2551 impl<'tcx> TyS<'tcx> {
2552 /// Iterator that walks `self` and any types reachable from
2553 /// `self`, in depth-first order. Note that just walks the types
2554 /// that appear in `self`, it does not descend into the fields of
2555 /// structs or variants. For example:
2558 /// isize => { isize }
2559 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2560 /// [isize] => { [isize], isize }
2562 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2563 TypeWalker::new(self)
2566 /// Iterator that walks the immediate children of `self`. Hence
2567 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2568 /// (but not `i32`, like `walk`).
2569 pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
2570 walk::walk_shallow(self)
2573 /// Walks `ty` and any types appearing within `ty`, invoking the
2574 /// callback `f` on each type. If the callback returns false, then the
2575 /// children of the current type are ignored.
2577 /// Note: prefer `ty.walk()` where possible.
2578 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2579 where F: FnMut(Ty<'tcx>) -> bool
2581 let mut walker = self.walk();
2582 while let Some(ty) = walker.next() {
2584 walker.skip_current_subtree();
2591 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2593 hir::MutMutable => MutBorrow,
2594 hir::MutImmutable => ImmBorrow,
2598 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2599 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2600 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2602 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2604 MutBorrow => hir::MutMutable,
2605 ImmBorrow => hir::MutImmutable,
2607 // We have no type corresponding to a unique imm borrow, so
2608 // use `&mut`. It gives all the capabilities of an `&uniq`
2609 // and hence is a safe "over approximation".
2610 UniqueImmBorrow => hir::MutMutable,
2614 pub fn to_user_str(&self) -> &'static str {
2616 MutBorrow => "mutable",
2617 ImmBorrow => "immutable",
2618 UniqueImmBorrow => "uniquely immutable",
2623 #[derive(Debug, Clone)]
2624 pub enum Attributes<'gcx> {
2625 Owned(Lrc<[ast::Attribute]>),
2626 Borrowed(&'gcx [ast::Attribute])
2629 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2630 type Target = [ast::Attribute];
2632 fn deref(&self) -> &[ast::Attribute] {
2634 &Attributes::Owned(ref data) => &data,
2635 &Attributes::Borrowed(data) => data
2640 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2641 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2642 self.typeck_tables_of(self.hir().body_owner_def_id(body))
2645 /// Returns an iterator of the def-ids for all body-owners in this
2646 /// crate. If you would prefer to iterate over the bodies
2647 /// themselves, you can do `self.hir().krate().body_ids.iter()`.
2650 ) -> impl Iterator<Item = DefId> + Captures<'tcx> + Captures<'gcx> + 'a {
2654 .map(move |&body_id| self.hir().body_owner_def_id(body_id))
2657 pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
2658 par_iter(&self.hir().krate().body_ids).for_each(|&body_id| {
2659 f(self.hir().body_owner_def_id(body_id))
2663 pub fn expr_span(self, id: NodeId) -> Span {
2664 match self.hir().find(id) {
2665 Some(Node::Expr(e)) => {
2669 bug!("Node id {} is not an expr: {:?}", id, f);
2672 bug!("Node id {} is not present in the node map", id);
2677 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2678 self.associated_items(id)
2679 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2683 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2684 self.associated_items(did).any(|item| {
2685 item.relevant_for_never()
2689 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2690 let is_associated_item = if let Some(node_id) = self.hir().as_local_node_id(def_id) {
2691 match self.hir().get(node_id) {
2692 Node::TraitItem(_) | Node::ImplItem(_) => true,
2696 match self.describe_def(def_id).expect("no def for def-id") {
2697 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2702 if is_associated_item {
2703 Some(self.associated_item(def_id))
2709 fn associated_item_from_trait_item_ref(self,
2710 parent_def_id: DefId,
2711 parent_vis: &hir::Visibility,
2712 trait_item_ref: &hir::TraitItemRef)
2714 let def_id = self.hir().local_def_id(trait_item_ref.id.node_id);
2715 let (kind, has_self) = match trait_item_ref.kind {
2716 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2717 hir::AssociatedItemKind::Method { has_self } => {
2718 (ty::AssociatedKind::Method, has_self)
2720 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2721 hir::AssociatedItemKind::Existential => bug!("only impls can have existentials"),
2725 ident: trait_item_ref.ident,
2727 // Visibility of trait items is inherited from their traits.
2728 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2729 defaultness: trait_item_ref.defaultness,
2731 container: TraitContainer(parent_def_id),
2732 method_has_self_argument: has_self
2736 fn associated_item_from_impl_item_ref(self,
2737 parent_def_id: DefId,
2738 impl_item_ref: &hir::ImplItemRef)
2740 let def_id = self.hir().local_def_id(impl_item_ref.id.node_id);
2741 let (kind, has_self) = match impl_item_ref.kind {
2742 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2743 hir::AssociatedItemKind::Method { has_self } => {
2744 (ty::AssociatedKind::Method, has_self)
2746 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2747 hir::AssociatedItemKind::Existential => (ty::AssociatedKind::Existential, false),
2751 ident: impl_item_ref.ident,
2753 // Visibility of trait impl items doesn't matter.
2754 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2755 defaultness: impl_item_ref.defaultness,
2757 container: ImplContainer(parent_def_id),
2758 method_has_self_argument: has_self
2762 pub fn field_index(self, node_id: NodeId, tables: &TypeckTables<'_>) -> usize {
2763 let hir_id = self.hir().node_to_hir_id(node_id);
2764 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2767 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2768 variant.fields.iter().position(|field| {
2769 self.adjust_ident(ident, variant.did, DUMMY_NODE_ID).0 == field.ident.modern()
2773 pub fn associated_items(
2776 ) -> AssociatedItemsIterator<'a, 'gcx, 'tcx> {
2777 // Ideally, we would use `-> impl Iterator` here, but it falls
2778 // afoul of the conservative "capture [restrictions]" we put
2779 // in place, so we use a hand-written iterator.
2781 // [restrictions]: https://github.com/rust-lang/rust/issues/34511#issuecomment-373423999
2782 AssociatedItemsIterator {
2784 def_ids: self.associated_item_def_ids(def_id),
2789 /// Returns `true` if the impls are the same polarity and the trait either
2790 /// has no items or is annotated #[marker] and prevents item overrides.
2791 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2792 if self.features().overlapping_marker_traits {
2793 let trait1_is_empty = self.impl_trait_ref(def_id1)
2794 .map_or(false, |trait_ref| {
2795 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2797 let trait2_is_empty = self.impl_trait_ref(def_id2)
2798 .map_or(false, |trait_ref| {
2799 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2801 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2804 } else if self.features().marker_trait_attr {
2805 let is_marker_impl = |def_id: DefId| -> bool {
2806 let trait_ref = self.impl_trait_ref(def_id);
2807 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2809 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2810 && is_marker_impl(def_id1)
2811 && is_marker_impl(def_id2)
2817 // Returns `ty::VariantDef` if `def` refers to a struct,
2818 // or variant or their constructors, panics otherwise.
2819 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2821 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2822 let enum_did = self.parent_def_id(did).unwrap();
2823 self.adt_def(enum_did).variant_with_id(did)
2825 Def::Struct(did) | Def::Union(did) => {
2826 self.adt_def(did).non_enum_variant()
2828 Def::StructCtor(ctor_did, ..) => {
2829 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2830 self.adt_def(did).non_enum_variant()
2832 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2836 /// Given a `VariantDef`, returns the def-id of the `AdtDef` of which it is a part.
2837 pub fn adt_def_id_of_variant(self, variant_def: &'tcx VariantDef) -> DefId {
2838 let def_key = self.def_key(variant_def.did);
2839 match def_key.disambiguated_data.data {
2840 // for enum variants and tuple structs, the def-id of the ADT itself
2841 // is the *parent* of the variant
2842 DefPathData::EnumVariant(..) | DefPathData::StructCtor =>
2843 DefId { krate: variant_def.did.krate, index: def_key.parent.unwrap() },
2845 // otherwise, for structs and unions, they share a def-id
2846 _ => variant_def.did,
2850 pub fn item_name(self, id: DefId) -> InternedString {
2851 if id.index == CRATE_DEF_INDEX {
2852 self.original_crate_name(id.krate).as_interned_str()
2854 let def_key = self.def_key(id);
2855 // The name of a StructCtor is that of its struct parent.
2856 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2857 self.item_name(DefId {
2859 index: def_key.parent.unwrap()
2862 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2863 bug!("item_name: no name for {:?}", self.def_path(id));
2869 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2870 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2874 ty::InstanceDef::Item(did) => {
2875 self.optimized_mir(did)
2877 ty::InstanceDef::VtableShim(..) |
2878 ty::InstanceDef::Intrinsic(..) |
2879 ty::InstanceDef::FnPtrShim(..) |
2880 ty::InstanceDef::Virtual(..) |
2881 ty::InstanceDef::ClosureOnceShim { .. } |
2882 ty::InstanceDef::DropGlue(..) |
2883 ty::InstanceDef::CloneShim(..) => {
2884 self.mir_shims(instance)
2889 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2890 /// Returns None if there is no MIR for the DefId
2891 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2892 if self.is_mir_available(did) {
2893 Some(self.optimized_mir(did))
2899 /// Get the attributes of a definition.
2900 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2901 if let Some(id) = self.hir().as_local_node_id(did) {
2902 Attributes::Borrowed(self.hir().attrs(id))
2904 Attributes::Owned(self.item_attrs(did))
2908 /// Determine whether an item is annotated with an attribute.
2909 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2910 attr::contains_name(&self.get_attrs(did), attr)
2913 /// Returns `true` if this is an `auto trait`.
2914 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
2915 self.trait_def(trait_def_id).has_auto_impl
2918 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
2919 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
2922 /// Given the def-id of an impl, return the def_id of the trait it implements.
2923 /// If it implements no trait, return `None`.
2924 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2925 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2928 /// If the given defid describes a method belonging to an impl, return the
2929 /// def-id of the impl that the method belongs to. Otherwise, return `None`.
2930 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2931 let item = if def_id.krate != LOCAL_CRATE {
2932 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2933 Some(self.associated_item(def_id))
2938 self.opt_associated_item(def_id)
2941 item.and_then(|trait_item|
2942 match trait_item.container {
2943 TraitContainer(_) => None,
2944 ImplContainer(def_id) => Some(def_id),
2949 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2950 /// with the name of the crate containing the impl.
2951 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2952 if impl_did.is_local() {
2953 let node_id = self.hir().as_local_node_id(impl_did).unwrap();
2954 Ok(self.hir().span(node_id))
2956 Err(self.crate_name(impl_did.krate))
2960 // Hygienically compare a use-site name (`use_name`) for a field or an associated item with its
2961 // supposed definition name (`def_name`). The method also needs `DefId` of the supposed
2962 // definition's parent/scope to perform comparison.
2963 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
2964 self.adjust_ident(use_name, def_parent_def_id, DUMMY_NODE_ID).0 == def_name.modern()
2967 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
2968 ident = ident.modern();
2969 let target_expansion = match scope.krate {
2970 LOCAL_CRATE => self.hir().definitions().expansion_that_defined(scope.index),
2973 let scope = match ident.span.adjust(target_expansion) {
2974 Some(actual_expansion) =>
2975 self.hir().definitions().parent_module_of_macro_def(actual_expansion),
2976 None if block == DUMMY_NODE_ID => DefId::local(CRATE_DEF_INDEX), // Dummy DefId
2977 None => self.hir().get_module_parent(block),
2983 pub struct AssociatedItemsIterator<'a, 'gcx: 'tcx, 'tcx: 'a> {
2984 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2985 def_ids: Lrc<Vec<DefId>>,
2989 impl Iterator for AssociatedItemsIterator<'_, '_, '_> {
2990 type Item = AssociatedItem;
2992 fn next(&mut self) -> Option<AssociatedItem> {
2993 let def_id = self.def_ids.get(self.next_index)?;
2994 self.next_index += 1;
2995 Some(self.tcx.associated_item(*def_id))
2999 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
3000 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
3001 F: FnOnce(&[hir::Freevar]) -> T,
3003 let def_id = self.hir().local_def_id(fid);
3004 match self.freevars(def_id) {
3011 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> AssociatedItem {
3012 let id = tcx.hir().as_local_node_id(def_id).unwrap();
3013 let parent_id = tcx.hir().get_parent(id);
3014 let parent_def_id = tcx.hir().local_def_id(parent_id);
3015 let parent_item = tcx.hir().expect_item(parent_id);
3016 match parent_item.node {
3017 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3018 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
3019 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
3021 debug_assert_eq!(assoc_item.def_id, def_id);
3026 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3027 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
3028 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
3031 debug_assert_eq!(assoc_item.def_id, def_id);
3039 span_bug!(parent_item.span,
3040 "unexpected parent of trait or impl item or item not found: {:?}",
3044 /// Calculates the Sized-constraint.
3046 /// In fact, there are only a few options for the types in the constraint:
3047 /// - an obviously-unsized type
3048 /// - a type parameter or projection whose Sizedness can't be known
3049 /// - a tuple of type parameters or projections, if there are multiple
3051 /// - a Error, if a type contained itself. The representability
3052 /// check should catch this case.
3053 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3055 -> &'tcx [Ty<'tcx>] {
3056 let def = tcx.adt_def(def_id);
3058 let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| {
3061 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
3064 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
3069 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3071 -> Lrc<Vec<DefId>> {
3072 let id = tcx.hir().as_local_node_id(def_id).unwrap();
3073 let item = tcx.hir().expect_item(id);
3074 let vec: Vec<_> = match item.node {
3075 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3076 trait_item_refs.iter()
3077 .map(|trait_item_ref| trait_item_ref.id)
3078 .map(|id| tcx.hir().local_def_id(id.node_id))
3081 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3082 impl_item_refs.iter()
3083 .map(|impl_item_ref| impl_item_ref.id)
3084 .map(|id| tcx.hir().local_def_id(id.node_id))
3087 hir::ItemKind::TraitAlias(..) => vec![],
3088 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
3093 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
3094 tcx.hir().span_if_local(def_id).unwrap()
3097 /// If the given def ID describes an item belonging to a trait,
3098 /// return the ID of the trait that the trait item belongs to.
3099 /// Otherwise, return `None`.
3100 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
3101 tcx.opt_associated_item(def_id)
3102 .and_then(|associated_item| {
3103 match associated_item.container {
3104 TraitContainer(def_id) => Some(def_id),
3105 ImplContainer(_) => None
3110 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
3111 pub fn is_impl_trait_defn(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> Option<DefId> {
3112 if let Some(node_id) = tcx.hir().as_local_node_id(def_id) {
3113 if let Node::Item(item) = tcx.hir().get(node_id) {
3114 if let hir::ItemKind::Existential(ref exist_ty) = item.node {
3115 return exist_ty.impl_trait_fn;
3122 /// Returns `true` if `def_id` is a trait alias.
3123 pub fn is_trait_alias(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> bool {
3124 if let Some(node_id) = tcx.hir().as_local_node_id(def_id) {
3125 if let Node::Item(item) = tcx.hir().get(node_id) {
3126 if let hir::ItemKind::TraitAlias(..) = item.node {
3134 /// See `ParamEnv` struct definition for details.
3135 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3139 // The param_env of an impl Trait type is its defining function's param_env
3140 if let Some(parent) = is_impl_trait_defn(tcx, def_id) {
3141 return param_env(tcx, parent);
3143 // Compute the bounds on Self and the type parameters.
3145 let InstantiatedPredicates { predicates } =
3146 tcx.predicates_of(def_id).instantiate_identity(tcx);
3148 // Finally, we have to normalize the bounds in the environment, in
3149 // case they contain any associated type projections. This process
3150 // can yield errors if the put in illegal associated types, like
3151 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
3152 // report these errors right here; this doesn't actually feel
3153 // right to me, because constructing the environment feels like a
3154 // kind of a "idempotent" action, but I'm not sure where would be
3155 // a better place. In practice, we construct environments for
3156 // every fn once during type checking, and we'll abort if there
3157 // are any errors at that point, so after type checking you can be
3158 // sure that this will succeed without errors anyway.
3160 let unnormalized_env = ty::ParamEnv::new(tcx.intern_predicates(&predicates),
3161 traits::Reveal::UserFacing);
3163 let body_id = tcx.hir().as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
3164 tcx.hir().maybe_body_owned_by(id).map_or(id, |body| body.node_id)
3166 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
3167 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
3170 fn crate_disambiguator<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3171 crate_num: CrateNum) -> CrateDisambiguator {
3172 assert_eq!(crate_num, LOCAL_CRATE);
3173 tcx.sess.local_crate_disambiguator()
3176 fn original_crate_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3177 crate_num: CrateNum) -> Symbol {
3178 assert_eq!(crate_num, LOCAL_CRATE);
3179 tcx.crate_name.clone()
3182 fn crate_hash<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3183 crate_num: CrateNum)
3185 assert_eq!(crate_num, LOCAL_CRATE);
3186 tcx.hir().crate_hash
3189 fn instance_def_size_estimate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3190 instance_def: InstanceDef<'tcx>)
3192 match instance_def {
3193 InstanceDef::Item(..) |
3194 InstanceDef::DropGlue(..) => {
3195 let mir = tcx.instance_mir(instance_def);
3196 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
3198 // Estimate the size of other compiler-generated shims to be 1.
3203 pub fn provide(providers: &mut ty::query::Providers<'_>) {
3204 context::provide(providers);
3205 erase_regions::provide(providers);
3206 layout::provide(providers);
3207 util::provide(providers);
3208 constness::provide(providers);
3209 *providers = ty::query::Providers {
3211 associated_item_def_ids,
3212 adt_sized_constraint,
3216 crate_disambiguator,
3217 original_crate_name,
3219 trait_impls_of: trait_def::trait_impls_of_provider,
3220 instance_def_size_estimate,
3225 /// A map for the local crate mapping each type to a vector of its
3226 /// inherent impls. This is not meant to be used outside of coherence;
3227 /// rather, you should request the vector for a specific type via
3228 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
3229 /// (constructing this map requires touching the entire crate).
3230 #[derive(Clone, Debug, Default)]
3231 pub struct CrateInherentImpls {
3232 pub inherent_impls: DefIdMap<Lrc<Vec<DefId>>>,
3235 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
3236 pub struct SymbolName {
3237 // FIXME: we don't rely on interning or equality here - better have
3238 // this be a `&'tcx str`.
3239 pub name: InternedString
3242 impl_stable_hash_for!(struct self::SymbolName {
3247 pub fn new(name: &str) -> SymbolName {
3249 name: Symbol::intern(name).as_interned_str()
3253 pub fn as_str(&self) -> LocalInternedString {
3258 impl fmt::Display for SymbolName {
3259 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3260 fmt::Display::fmt(&self.name, fmt)
3264 impl fmt::Debug for SymbolName {
3265 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3266 fmt::Display::fmt(&self.name, fmt)