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::subst::{Subst, Substs};
36 use ty::util::{IntTypeExt, Discr};
37 use ty::walk::TypeWalker;
38 use util::captures::Captures;
39 use util::nodemap::{NodeSet, DefIdMap, FxHashMap};
40 use arena::SyncDroplessArena;
41 use session::DataTypeKind;
43 use serialize::{self, Encodable, Encoder};
44 use std::cell::RefCell;
45 use std::cmp::{self, Ordering};
47 use std::hash::{Hash, Hasher};
49 use rustc_data_structures::sync::{self, Lrc, ParallelIterator, par_iter};
51 use std::vec::IntoIter;
53 use syntax::ast::{self, DUMMY_NODE_ID, Name, Ident, NodeId};
55 use syntax::ext::hygiene::Mark;
56 use syntax::symbol::{keywords, Symbol, LocalInternedString, InternedString};
57 use syntax_pos::{DUMMY_SP, Span};
60 use rustc_data_structures::indexed_vec::Idx;
61 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
66 pub use self::sty::{Binder, 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};
87 pub use self::instance::{Instance, InstanceDef};
89 pub use self::trait_def::TraitDef;
91 pub use self::query::queries;
103 pub mod inhabitedness;
120 mod structural_impls;
125 /// The complete set of all analyses described in this module. This is
126 /// produced by the driver and fed to codegen and later passes.
128 /// NB: These contents are being migrated into queries using the
129 /// *on-demand* infrastructure.
131 pub struct CrateAnalysis {
132 pub access_levels: Lrc<AccessLevels>,
134 pub glob_map: Option<hir::GlobMap>,
138 pub struct Resolutions {
139 pub freevars: FreevarMap,
140 pub trait_map: TraitMap,
141 pub maybe_unused_trait_imports: NodeSet,
142 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
143 pub export_map: ExportMap,
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_SKOL = 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 NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
471 TypeFlags::HAS_SELF.bits |
472 TypeFlags::HAS_RE_EARLY_BOUND.bits;
474 // Flags representing the nominal content of a type,
475 // computed by FlagsComputation. If you add a new nominal
476 // flag, it should be added here too.
477 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
478 TypeFlags::HAS_SELF.bits |
479 TypeFlags::HAS_TY_INFER.bits |
480 TypeFlags::HAS_RE_INFER.bits |
481 TypeFlags::HAS_RE_SKOL.bits |
482 TypeFlags::HAS_RE_EARLY_BOUND.bits |
483 TypeFlags::HAS_FREE_REGIONS.bits |
484 TypeFlags::HAS_TY_ERR.bits |
485 TypeFlags::HAS_PROJECTION.bits |
486 TypeFlags::HAS_TY_CLOSURE.bits |
487 TypeFlags::HAS_FREE_LOCAL_NAMES.bits |
488 TypeFlags::KEEP_IN_LOCAL_TCX.bits |
489 TypeFlags::HAS_RE_LATE_BOUND.bits;
493 pub struct TyS<'tcx> {
494 pub sty: TyKind<'tcx>,
495 pub flags: TypeFlags,
497 /// This is a kind of confusing thing: it stores the smallest
500 /// (a) the binder itself captures nothing but
501 /// (b) all the late-bound things within the type are captured
502 /// by some sub-binder.
504 /// So, for a type without any late-bound things, like `u32`, this
505 /// will be INNERMOST, because that is the innermost binder that
506 /// captures nothing. But for a type `&'D u32`, where `'D` is a
507 /// late-bound region with debruijn index D, this would be D+1 --
508 /// the binder itself does not capture D, but D is captured by an
511 /// We call this concept an "exclusive" binder D (because all
512 /// debruijn indices within the type are contained within `0..D`
514 outer_exclusive_binder: ty::DebruijnIndex,
517 impl<'tcx> Ord for TyS<'tcx> {
518 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
519 self.sty.cmp(&other.sty)
523 impl<'tcx> PartialOrd for TyS<'tcx> {
524 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
525 Some(self.sty.cmp(&other.sty))
529 impl<'tcx> PartialEq for TyS<'tcx> {
531 fn eq(&self, other: &TyS<'tcx>) -> bool {
535 impl<'tcx> Eq for TyS<'tcx> {}
537 impl<'tcx> Hash for TyS<'tcx> {
538 fn hash<H: Hasher>(&self, s: &mut H) {
539 (self as *const TyS<'_>).hash(s)
543 impl<'tcx> TyS<'tcx> {
544 pub fn is_primitive_ty(&self) -> bool {
551 TyKind::Infer(InferTy::IntVar(_)) |
552 TyKind::Infer(InferTy::FloatVar(_)) |
553 TyKind::Infer(InferTy::FreshIntTy(_)) |
554 TyKind::Infer(InferTy::FreshFloatTy(_)) => true,
555 TyKind::Ref(_, x, _) => x.is_primitive_ty(),
560 pub fn is_suggestable(&self) -> bool {
565 TyKind::Dynamic(..) |
566 TyKind::Closure(..) |
568 TyKind::Projection(..) => false,
574 impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for ty::TyS<'gcx> {
575 fn hash_stable<W: StableHasherResult>(&self,
576 hcx: &mut StableHashingContext<'a>,
577 hasher: &mut StableHasher<W>) {
581 // The other fields just provide fast access to information that is
582 // also contained in `sty`, so no need to hash them.
585 outer_exclusive_binder: _,
588 sty.hash_stable(hcx, hasher);
592 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
594 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
595 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
597 pub type CanonicalTy<'gcx> = Canonical<'gcx, Ty<'gcx>>;
600 /// A dummy type used to force List to by unsized without requiring fat pointers
601 type OpaqueListContents;
604 /// A wrapper for slices with the additional invariant
605 /// that the slice is interned and no other slice with
606 /// the same contents can exist in the same context.
607 /// This means we can use pointer for both
608 /// equality comparisons and hashing.
609 /// Note: `Slice` was already taken by the `Ty`.
614 opaque: OpaqueListContents,
617 unsafe impl<T: Sync> Sync for List<T> {}
619 impl<T: Copy> List<T> {
621 fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx List<T> {
622 assert!(!mem::needs_drop::<T>());
623 assert!(mem::size_of::<T>() != 0);
624 assert!(slice.len() != 0);
626 // Align up the size of the len (usize) field
627 let align = mem::align_of::<T>();
628 let align_mask = align - 1;
629 let offset = mem::size_of::<usize>();
630 let offset = (offset + align_mask) & !align_mask;
632 let size = offset + slice.len() * mem::size_of::<T>();
634 let mem = arena.alloc_raw(
636 cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
638 let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
640 result.len = slice.len();
642 // Write the elements
643 let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
644 arena_slice.copy_from_slice(slice);
651 impl<T: fmt::Debug> fmt::Debug for List<T> {
652 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
657 impl<T: Encodable> Encodable for List<T> {
659 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
664 impl<T> Ord for List<T> where T: Ord {
665 fn cmp(&self, other: &List<T>) -> Ordering {
666 if self == other { Ordering::Equal } else {
667 <[T] as Ord>::cmp(&**self, &**other)
672 impl<T> PartialOrd for List<T> where T: PartialOrd {
673 fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> {
674 if self == other { Some(Ordering::Equal) } else {
675 <[T] as PartialOrd>::partial_cmp(&**self, &**other)
680 impl<T: PartialEq> PartialEq for List<T> {
682 fn eq(&self, other: &List<T>) -> bool {
686 impl<T: Eq> Eq for List<T> {}
688 impl<T> Hash for List<T> {
690 fn hash<H: Hasher>(&self, s: &mut H) {
691 (self as *const List<T>).hash(s)
695 impl<T> Deref for List<T> {
698 fn deref(&self) -> &[T] {
700 slice::from_raw_parts(self.data.as_ptr(), self.len)
705 impl<'a, T> IntoIterator for &'a List<T> {
707 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
709 fn into_iter(self) -> Self::IntoIter {
714 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
718 pub fn empty<'a>() -> &'a List<T> {
719 #[repr(align(64), C)]
720 struct EmptySlice([u8; 64]);
721 static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
722 assert!(mem::align_of::<T>() <= 64);
724 &*(&EMPTY_SLICE as *const _ as *const List<T>)
729 /// Upvars do not get their own node-id. Instead, we use the pair of
730 /// the original var id (that is, the root variable that is referenced
731 /// by the upvar) and the id of the closure expression.
732 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
734 pub var_id: hir::HirId,
735 pub closure_expr_id: LocalDefId,
738 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
739 pub enum BorrowKind {
740 /// Data must be immutable and is aliasable.
743 /// Data must be immutable but not aliasable. This kind of borrow
744 /// cannot currently be expressed by the user and is used only in
745 /// implicit closure bindings. It is needed when the closure
746 /// is borrowing or mutating a mutable referent, e.g.:
748 /// let x: &mut isize = ...;
749 /// let y = || *x += 5;
751 /// If we were to try to translate this closure into a more explicit
752 /// form, we'd encounter an error with the code as written:
754 /// struct Env { x: & &mut isize }
755 /// let x: &mut isize = ...;
756 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
757 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
759 /// This is then illegal because you cannot mutate a `&mut` found
760 /// in an aliasable location. To solve, you'd have to translate with
761 /// an `&mut` borrow:
763 /// struct Env { x: & &mut isize }
764 /// let x: &mut isize = ...;
765 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
766 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
768 /// Now the assignment to `**env.x` is legal, but creating a
769 /// mutable pointer to `x` is not because `x` is not mutable. We
770 /// could fix this by declaring `x` as `let mut x`. This is ok in
771 /// user code, if awkward, but extra weird for closures, since the
772 /// borrow is hidden.
774 /// So we introduce a "unique imm" borrow -- the referent is
775 /// immutable, but not aliasable. This solves the problem. For
776 /// simplicity, we don't give users the way to express this
777 /// borrow, it's just used when translating closures.
780 /// Data is mutable and not aliasable.
784 /// Information describing the capture of an upvar. This is computed
785 /// during `typeck`, specifically by `regionck`.
786 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
787 pub enum UpvarCapture<'tcx> {
788 /// Upvar is captured by value. This is always true when the
789 /// closure is labeled `move`, but can also be true in other cases
790 /// depending on inference.
793 /// Upvar is captured by reference.
794 ByRef(UpvarBorrow<'tcx>),
797 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
798 pub struct UpvarBorrow<'tcx> {
799 /// The kind of borrow: by-ref upvars have access to shared
800 /// immutable borrows, which are not part of the normal language
802 pub kind: BorrowKind,
804 /// Region of the resulting reference.
805 pub region: ty::Region<'tcx>,
808 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
810 #[derive(Copy, Clone)]
811 pub struct ClosureUpvar<'tcx> {
817 #[derive(Clone, Copy, PartialEq, Eq)]
818 pub enum IntVarValue {
820 UintType(ast::UintTy),
823 #[derive(Clone, Copy, PartialEq, Eq)]
824 pub struct FloatVarValue(pub ast::FloatTy);
826 impl ty::EarlyBoundRegion {
827 pub fn to_bound_region(&self) -> ty::BoundRegion {
828 ty::BoundRegion::BrNamed(self.def_id, self.name)
831 /// Does this early bound region have a name? Early bound regions normally
832 /// always have names except when using anonymous lifetimes (`'_`).
833 pub fn has_name(&self) -> bool {
834 self.name != keywords::UnderscoreLifetime.name().as_interned_str()
838 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
839 pub enum GenericParamDefKind {
843 object_lifetime_default: ObjectLifetimeDefault,
844 synthetic: Option<hir::SyntheticTyParamKind>,
848 #[derive(Clone, RustcEncodable, RustcDecodable)]
849 pub struct GenericParamDef {
850 pub name: InternedString,
854 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
855 /// on generic parameter `'a`/`T`, asserts data behind the parameter
856 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
857 pub pure_wrt_drop: bool,
859 pub kind: GenericParamDefKind,
862 impl GenericParamDef {
863 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
864 if let GenericParamDefKind::Lifetime = self.kind {
865 ty::EarlyBoundRegion {
871 bug!("cannot convert a non-lifetime parameter def to an early bound region")
875 pub fn to_bound_region(&self) -> ty::BoundRegion {
876 if let GenericParamDefKind::Lifetime = self.kind {
877 self.to_early_bound_region_data().to_bound_region()
879 bug!("cannot convert a non-lifetime parameter def to an early bound region")
885 pub struct GenericParamCount {
886 pub lifetimes: usize,
890 /// Information about the formal type/lifetime parameters associated
891 /// with an item or method. Analogous to hir::Generics.
893 /// The ordering of parameters is the same as in Subst (excluding child generics):
894 /// Self (optionally), Lifetime params..., Type params...
895 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
896 pub struct Generics {
897 pub parent: Option<DefId>,
898 pub parent_count: usize,
899 pub params: Vec<GenericParamDef>,
901 /// Reverse map to the `index` field of each `GenericParamDef`
902 pub param_def_id_to_index: FxHashMap<DefId, u32>,
905 pub has_late_bound_regions: Option<Span>,
908 impl<'a, 'gcx, 'tcx> Generics {
909 pub fn count(&self) -> usize {
910 self.parent_count + self.params.len()
913 pub fn own_counts(&self) -> GenericParamCount {
914 // We could cache this as a property of `GenericParamCount`, but
915 // the aim is to refactor this away entirely eventually and the
916 // presence of this method will be a constant reminder.
917 let mut own_counts: GenericParamCount = Default::default();
919 for param in &self.params {
921 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
922 GenericParamDefKind::Type { .. } => own_counts.types += 1,
929 pub fn requires_monomorphization(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
930 for param in &self.params {
932 GenericParamDefKind::Type { .. } => return true,
933 GenericParamDefKind::Lifetime => {}
936 if let Some(parent_def_id) = self.parent {
937 let parent = tcx.generics_of(parent_def_id);
938 parent.requires_monomorphization(tcx)
944 pub fn region_param(&'tcx self,
945 param: &EarlyBoundRegion,
946 tcx: TyCtxt<'a, 'gcx, 'tcx>)
947 -> &'tcx GenericParamDef
949 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
950 let param = &self.params[index as usize];
952 ty::GenericParamDefKind::Lifetime => param,
953 _ => bug!("expected lifetime parameter, but found another generic parameter")
956 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
957 .region_param(param, tcx)
961 /// Returns the `GenericParamDef` associated with this `ParamTy`.
962 pub fn type_param(&'tcx self,
964 tcx: TyCtxt<'a, 'gcx, 'tcx>)
965 -> &'tcx GenericParamDef {
966 if let Some(index) = param.idx.checked_sub(self.parent_count as u32) {
967 let param = &self.params[index as usize];
969 ty::GenericParamDefKind::Type {..} => param,
970 _ => bug!("expected type parameter, but found another generic parameter")
973 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
974 .type_param(param, tcx)
979 /// Bounds on generics.
980 #[derive(Clone, Default)]
981 pub struct GenericPredicates<'tcx> {
982 pub parent: Option<DefId>,
983 pub predicates: Vec<(Predicate<'tcx>, Span)>,
986 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
987 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
989 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
990 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
991 -> InstantiatedPredicates<'tcx> {
992 let mut instantiated = InstantiatedPredicates::empty();
993 self.instantiate_into(tcx, &mut instantiated, substs);
997 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
998 -> InstantiatedPredicates<'tcx> {
999 InstantiatedPredicates {
1000 predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
1004 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1005 instantiated: &mut InstantiatedPredicates<'tcx>,
1006 substs: &Substs<'tcx>) {
1007 if let Some(def_id) = self.parent {
1008 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
1010 instantiated.predicates.extend(
1011 self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)),
1015 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1016 -> InstantiatedPredicates<'tcx> {
1017 let mut instantiated = InstantiatedPredicates::empty();
1018 self.instantiate_identity_into(tcx, &mut instantiated);
1022 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1023 instantiated: &mut InstantiatedPredicates<'tcx>) {
1024 if let Some(def_id) = self.parent {
1025 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
1027 instantiated.predicates.extend(self.predicates.iter().map(|&(p, _)| p))
1030 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1031 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
1032 -> InstantiatedPredicates<'tcx>
1034 assert_eq!(self.parent, None);
1035 InstantiatedPredicates {
1036 predicates: self.predicates.iter().map(|(pred, _)| {
1037 pred.subst_supertrait(tcx, poly_trait_ref)
1043 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1044 pub enum Predicate<'tcx> {
1045 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
1046 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1047 /// would be the type parameters.
1048 Trait(PolyTraitPredicate<'tcx>),
1051 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1054 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1056 /// where `<T as TraitRef>::Name == X`, approximately.
1057 /// See the `ProjectionPredicate` struct for details.
1058 Projection(PolyProjectionPredicate<'tcx>),
1060 /// no syntax: `T` well-formed
1061 WellFormed(Ty<'tcx>),
1063 /// trait must be object-safe
1066 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
1067 /// for some substitutions `...` and `T` being a closure type.
1068 /// Satisfied (or refuted) once we know the closure's kind.
1069 ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
1072 Subtype(PolySubtypePredicate<'tcx>),
1074 /// Constant initializer must evaluate successfully.
1075 ConstEvaluatable(DefId, &'tcx Substs<'tcx>),
1078 /// The crate outlives map is computed during typeck and contains the
1079 /// outlives of every item in the local crate. You should not use it
1080 /// directly, because to do so will make your pass dependent on the
1081 /// HIR of every item in the local crate. Instead, use
1082 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1084 pub struct CratePredicatesMap<'tcx> {
1085 /// For each struct with outlive bounds, maps to a vector of the
1086 /// predicate of its outlive bounds. If an item has no outlives
1087 /// bounds, it will have no entry.
1088 pub predicates: FxHashMap<DefId, Lrc<Vec<ty::Predicate<'tcx>>>>,
1090 /// An empty vector, useful for cloning.
1091 pub empty_predicate: Lrc<Vec<ty::Predicate<'tcx>>>,
1094 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1095 fn as_ref(&self) -> &Predicate<'tcx> {
1100 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
1101 /// Performs a substitution suitable for going from a
1102 /// poly-trait-ref to supertraits that must hold if that
1103 /// poly-trait-ref holds. This is slightly different from a normal
1104 /// substitution in terms of what happens with bound regions. See
1105 /// lengthy comment below for details.
1106 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1107 trait_ref: &ty::PolyTraitRef<'tcx>)
1108 -> ty::Predicate<'tcx>
1110 // The interaction between HRTB and supertraits is not entirely
1111 // obvious. Let me walk you (and myself) through an example.
1113 // Let's start with an easy case. Consider two traits:
1115 // trait Foo<'a> : Bar<'a,'a> { }
1116 // trait Bar<'b,'c> { }
1118 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
1119 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
1120 // knew that `Foo<'x>` (for any 'x) then we also know that
1121 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1122 // normal substitution.
1124 // In terms of why this is sound, the idea is that whenever there
1125 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1126 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1127 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1130 // Another example to be careful of is this:
1132 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
1133 // trait Bar1<'b,'c> { }
1135 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
1136 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
1137 // reason is similar to the previous example: any impl of
1138 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
1139 // basically we would want to collapse the bound lifetimes from
1140 // the input (`trait_ref`) and the supertraits.
1142 // To achieve this in practice is fairly straightforward. Let's
1143 // consider the more complicated scenario:
1145 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
1146 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
1147 // where both `'x` and `'b` would have a DB index of 1.
1148 // The substitution from the input trait-ref is therefore going to be
1149 // `'a => 'x` (where `'x` has a DB index of 1).
1150 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1151 // early-bound parameter and `'b' is a late-bound parameter with a
1153 // - If we replace `'a` with `'x` from the input, it too will have
1154 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1155 // just as we wanted.
1157 // There is only one catch. If we just apply the substitution `'a
1158 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1159 // adjust the DB index because we substituting into a binder (it
1160 // tries to be so smart...) resulting in `for<'x> for<'b>
1161 // Bar1<'x,'b>` (we have no syntax for this, so use your
1162 // imagination). Basically the 'x will have DB index of 2 and 'b
1163 // will have DB index of 1. Not quite what we want. So we apply
1164 // the substitution to the *contents* of the trait reference,
1165 // rather than the trait reference itself (put another way, the
1166 // substitution code expects equal binding levels in the values
1167 // from the substitution and the value being substituted into, and
1168 // this trick achieves that).
1170 let substs = &trait_ref.skip_binder().substs;
1172 Predicate::Trait(ref binder) =>
1173 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1174 Predicate::Subtype(ref binder) =>
1175 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1176 Predicate::RegionOutlives(ref binder) =>
1177 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1178 Predicate::TypeOutlives(ref binder) =>
1179 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1180 Predicate::Projection(ref binder) =>
1181 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1182 Predicate::WellFormed(data) =>
1183 Predicate::WellFormed(data.subst(tcx, substs)),
1184 Predicate::ObjectSafe(trait_def_id) =>
1185 Predicate::ObjectSafe(trait_def_id),
1186 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1187 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1188 Predicate::ConstEvaluatable(def_id, const_substs) =>
1189 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1194 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1195 pub struct TraitPredicate<'tcx> {
1196 pub trait_ref: TraitRef<'tcx>
1198 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1200 impl<'tcx> TraitPredicate<'tcx> {
1201 pub fn def_id(&self) -> DefId {
1202 self.trait_ref.def_id
1205 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
1206 self.trait_ref.input_types()
1209 pub fn self_ty(&self) -> Ty<'tcx> {
1210 self.trait_ref.self_ty()
1214 impl<'tcx> PolyTraitPredicate<'tcx> {
1215 pub fn def_id(&self) -> DefId {
1216 // ok to skip binder since trait def-id does not care about regions
1217 self.skip_binder().def_id()
1221 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
1222 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
1223 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1224 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>,
1226 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>,
1228 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1229 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1231 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1232 pub struct SubtypePredicate<'tcx> {
1233 pub a_is_expected: bool,
1237 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1239 /// This kind of predicate has no *direct* correspondent in the
1240 /// syntax, but it roughly corresponds to the syntactic forms:
1242 /// 1. `T : TraitRef<..., Item=Type>`
1243 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1245 /// In particular, form #1 is "desugared" to the combination of a
1246 /// normal trait predicate (`T : TraitRef<...>`) and one of these
1247 /// predicates. Form #2 is a broader form in that it also permits
1248 /// equality between arbitrary types. Processing an instance of
1249 /// Form #2 eventually yields one of these `ProjectionPredicate`
1250 /// instances to normalize the LHS.
1251 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1252 pub struct ProjectionPredicate<'tcx> {
1253 pub projection_ty: ProjectionTy<'tcx>,
1257 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1259 impl<'tcx> PolyProjectionPredicate<'tcx> {
1260 /// Returns the `DefId` of the associated item being projected.
1261 pub fn item_def_id(&self) -> DefId {
1262 self.skip_binder().projection_ty.item_def_id
1265 pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'_, '_, '_>) -> PolyTraitRef<'tcx> {
1266 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
1267 // `self.0.trait_ref` is permitted to have escaping regions.
1268 // This is because here `self` has a `Binder` and so does our
1269 // return value, so we are preserving the number of binding
1271 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1274 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1275 self.map_bound(|predicate| predicate.ty)
1278 /// The `DefId` of the `TraitItem` for the associated type.
1280 /// Note that this is not the `DefId` of the `TraitRef` containing this
1281 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
1282 pub fn projection_def_id(&self) -> DefId {
1283 // okay to skip binder since trait def-id does not care about regions
1284 self.skip_binder().projection_ty.item_def_id
1288 pub trait ToPolyTraitRef<'tcx> {
1289 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1292 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1293 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1294 ty::Binder::dummy(self.clone())
1298 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1299 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1300 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1304 pub trait ToPredicate<'tcx> {
1305 fn to_predicate(&self) -> Predicate<'tcx>;
1308 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1309 fn to_predicate(&self) -> Predicate<'tcx> {
1310 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1311 trait_ref: self.clone()
1316 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1317 fn to_predicate(&self) -> Predicate<'tcx> {
1318 ty::Predicate::Trait(self.to_poly_trait_predicate())
1322 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1323 fn to_predicate(&self) -> Predicate<'tcx> {
1324 Predicate::RegionOutlives(self.clone())
1328 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1329 fn to_predicate(&self) -> Predicate<'tcx> {
1330 Predicate::TypeOutlives(self.clone())
1334 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1335 fn to_predicate(&self) -> Predicate<'tcx> {
1336 Predicate::Projection(self.clone())
1340 impl<'tcx> Predicate<'tcx> {
1341 /// Iterates over the types in this predicate. Note that in all
1342 /// cases this is skipping over a binder, so late-bound regions
1343 /// with depth 0 are bound by the predicate.
1344 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1345 let vec: Vec<_> = match *self {
1346 ty::Predicate::Trait(ref data) => {
1347 data.skip_binder().input_types().collect()
1349 ty::Predicate::Subtype(binder) => {
1350 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1353 ty::Predicate::TypeOutlives(binder) => {
1354 vec![binder.skip_binder().0]
1356 ty::Predicate::RegionOutlives(..) => {
1359 ty::Predicate::Projection(ref data) => {
1360 let inner = data.skip_binder();
1361 inner.projection_ty.substs.types().chain(Some(inner.ty)).collect()
1363 ty::Predicate::WellFormed(data) => {
1366 ty::Predicate::ObjectSafe(_trait_def_id) => {
1369 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1370 closure_substs.substs.types().collect()
1372 ty::Predicate::ConstEvaluatable(_, substs) => {
1373 substs.types().collect()
1377 // FIXME: The only reason to collect into a vector here is that I was
1378 // too lazy to make the full (somewhat complicated) iterator
1379 // type that would be needed here. But I wanted this fn to
1380 // return an iterator conceptually, rather than a `Vec`, so as
1381 // to be closer to `Ty::walk`.
1385 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1387 Predicate::Trait(ref t) => {
1388 Some(t.to_poly_trait_ref())
1390 Predicate::Projection(..) |
1391 Predicate::Subtype(..) |
1392 Predicate::RegionOutlives(..) |
1393 Predicate::WellFormed(..) |
1394 Predicate::ObjectSafe(..) |
1395 Predicate::ClosureKind(..) |
1396 Predicate::TypeOutlives(..) |
1397 Predicate::ConstEvaluatable(..) => {
1403 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1405 Predicate::TypeOutlives(data) => {
1408 Predicate::Trait(..) |
1409 Predicate::Projection(..) |
1410 Predicate::Subtype(..) |
1411 Predicate::RegionOutlives(..) |
1412 Predicate::WellFormed(..) |
1413 Predicate::ObjectSafe(..) |
1414 Predicate::ClosureKind(..) |
1415 Predicate::ConstEvaluatable(..) => {
1422 /// Represents the bounds declared on a particular set of type
1423 /// parameters. Should eventually be generalized into a flag list of
1424 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1425 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1426 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1427 /// the `GenericPredicates` are expressed in terms of the bound type
1428 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1429 /// represented a set of bounds for some particular instantiation,
1430 /// meaning that the generic parameters have been substituted with
1435 /// struct Foo<T,U:Bar<T>> { ... }
1437 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1438 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1439 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1440 /// [usize:Bar<isize>]]`.
1442 pub struct InstantiatedPredicates<'tcx> {
1443 pub predicates: Vec<Predicate<'tcx>>,
1446 impl<'tcx> InstantiatedPredicates<'tcx> {
1447 pub fn empty() -> InstantiatedPredicates<'tcx> {
1448 InstantiatedPredicates { predicates: vec![] }
1451 pub fn is_empty(&self) -> bool {
1452 self.predicates.is_empty()
1456 /// "Universes" are used during type- and trait-checking in the
1457 /// presence of `for<..>` binders to control what sets of names are
1458 /// visible. Universes are arranged into a tree: the root universe
1459 /// contains names that are always visible. Each child then adds a new
1460 /// set of names that are visible, in addition to those of its parent.
1461 /// We say that the child universe "extends" the parent universe with
1464 /// To make this more concrete, consider this program:
1468 /// fn bar<T>(x: T) {
1469 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1473 /// The struct name `Foo` is in the root universe U0. But the type
1474 /// parameter `T`, introduced on `bar`, is in an extended universe U1
1475 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
1476 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
1477 /// region `'a` is in a universe U2 that extends U1, because we can
1478 /// name it inside the fn type but not outside.
1480 /// Universes are used to do type- and trait-checking around these
1481 /// "forall" binders (also called **universal quantification**). The
1482 /// idea is that when, in the body of `bar`, we refer to `T` as a
1483 /// type, we aren't referring to any type in particular, but rather a
1484 /// kind of "fresh" type that is distinct from all other types we have
1485 /// actually declared. This is called a **placeholder** type, and we
1486 /// use universes to talk about this. In other words, a type name in
1487 /// universe 0 always corresponds to some "ground" type that the user
1488 /// declared, but a type name in a non-zero universe is a placeholder
1489 /// type -- an idealized representative of "types in general" that we
1490 /// use for checking generic functions.
1492 pub struct UniverseIndex {
1493 DEBUG_FORMAT = "U{}",
1497 impl_stable_hash_for!(struct UniverseIndex { private });
1499 impl UniverseIndex {
1500 pub const ROOT: UniverseIndex = UniverseIndex::from_u32_const(0);
1502 /// Returns the "next" universe index in order -- this new index
1503 /// is considered to extend all previous universes. This
1504 /// corresponds to entering a `forall` quantifier. So, for
1505 /// example, suppose we have this type in universe `U`:
1508 /// for<'a> fn(&'a u32)
1511 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1512 /// new universe that extends `U` -- in this new universe, we can
1513 /// name the region `'a`, but that region was not nameable from
1514 /// `U` because it was not in scope there.
1515 pub fn next_universe(self) -> UniverseIndex {
1516 UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
1519 /// `true` if `self` can name a name from `other` -- in other words,
1520 /// if the set of names in `self` is a superset of those in
1521 /// `other` (`self >= other`).
1522 pub fn can_name(self, other: UniverseIndex) -> bool {
1523 self.private >= other.private
1526 /// `true` if `self` cannot name some names from `other` -- in other
1527 /// words, if the set of names in `self` is a strict subset of
1528 /// those in `other` (`self < other`).
1529 pub fn cannot_name(self, other: UniverseIndex) -> bool {
1530 self.private < other.private
1534 /// The "placeholder index" fully defines a placeholder region.
1535 /// Placeholder regions are identified by both a **universe** as well
1536 /// as a "bound-region" within that universe. The `bound_region` is
1537 /// basically a name -- distinct bound regions within the same
1538 /// universe are just two regions with an unknown relationship to one
1540 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
1541 pub struct Placeholder {
1542 pub universe: UniverseIndex,
1543 pub name: BoundRegion,
1546 impl_stable_hash_for!(struct Placeholder { universe, name });
1548 /// When type checking, we use the `ParamEnv` to track
1549 /// details about the set of where-clauses that are in scope at this
1550 /// particular point.
1551 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1552 pub struct ParamEnv<'tcx> {
1553 /// Obligations that the caller must satisfy. This is basically
1554 /// the set of bounds on the in-scope type parameters, translated
1555 /// into Obligations, and elaborated and normalized.
1556 pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1558 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1559 /// want `Reveal::All` -- note that this is always paired with an
1560 /// empty environment. To get that, use `ParamEnv::reveal()`.
1561 pub reveal: traits::Reveal,
1564 impl<'tcx> ParamEnv<'tcx> {
1565 /// Construct a trait environment suitable for contexts where
1566 /// there are no where clauses in scope. Hidden types (like `impl
1567 /// Trait`) are left hidden, so this is suitable for ordinary
1569 pub fn empty() -> Self {
1570 Self::new(List::empty(), Reveal::UserFacing)
1573 /// Construct a trait environment with no where clauses in scope
1574 /// where the values of all `impl Trait` and other hidden types
1575 /// are revealed. This is suitable for monomorphized, post-typeck
1576 /// environments like codegen or doing optimizations.
1578 /// N.B. If you want to have predicates in scope, use `ParamEnv::new`,
1579 /// or invoke `param_env.with_reveal_all()`.
1580 pub fn reveal_all() -> Self {
1581 Self::new(List::empty(), Reveal::All)
1584 /// Construct a trait environment with the given set of predicates.
1585 pub fn new(caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1588 ty::ParamEnv { caller_bounds, reveal }
1591 /// Returns a new parameter environment with the same clauses, but
1592 /// which "reveals" the true results of projections in all cases
1593 /// (even for associated types that are specializable). This is
1594 /// the desired behavior during codegen and certain other special
1595 /// contexts; normally though we want to use `Reveal::UserFacing`,
1596 /// which is the default.
1597 pub fn with_reveal_all(self) -> Self {
1598 ty::ParamEnv { reveal: Reveal::All, ..self }
1601 /// Returns this same environment but with no caller bounds.
1602 pub fn without_caller_bounds(self) -> Self {
1603 ty::ParamEnv { caller_bounds: List::empty(), ..self }
1606 /// Creates a suitable environment in which to perform trait
1607 /// queries on the given value. When type-checking, this is simply
1608 /// the pair of the environment plus value. But when reveal is set to
1609 /// All, then if `value` does not reference any type parameters, we will
1610 /// pair it with the empty environment. This improves caching and is generally
1613 /// NB: We preserve the environment when type-checking because it
1614 /// is possible for the user to have wacky where-clauses like
1615 /// `where Box<u32>: Copy`, which are clearly never
1616 /// satisfiable. We generally want to behave as if they were true,
1617 /// although the surrounding function is never reachable.
1618 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1620 Reveal::UserFacing => {
1629 || value.needs_infer()
1630 || value.has_param_types()
1631 || value.has_self_ty()
1639 param_env: self.without_caller_bounds(),
1648 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1649 pub struct ParamEnvAnd<'tcx, T> {
1650 pub param_env: ParamEnv<'tcx>,
1654 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1655 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1656 (self.param_env, self.value)
1660 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'gcx, T>
1661 where T: HashStable<StableHashingContext<'a>>
1663 fn hash_stable<W: StableHasherResult>(&self,
1664 hcx: &mut StableHashingContext<'a>,
1665 hasher: &mut StableHasher<W>) {
1671 param_env.hash_stable(hcx, hasher);
1672 value.hash_stable(hcx, hasher);
1676 #[derive(Copy, Clone, Debug)]
1677 pub struct Destructor {
1678 /// The def-id of the destructor method
1683 pub struct AdtFlags: u32 {
1684 const NO_ADT_FLAGS = 0;
1685 const IS_ENUM = 1 << 0;
1686 const IS_PHANTOM_DATA = 1 << 1;
1687 const IS_FUNDAMENTAL = 1 << 2;
1688 const IS_UNION = 1 << 3;
1689 const IS_BOX = 1 << 4;
1690 /// Indicates whether the type is an `Arc`.
1691 const IS_ARC = 1 << 5;
1692 /// Indicates whether the type is an `Rc`.
1693 const IS_RC = 1 << 6;
1694 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1695 /// (i.e., this flag is never set unless this ADT is an enum).
1696 const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 7;
1701 pub struct VariantFlags: u32 {
1702 const NO_VARIANT_FLAGS = 0;
1703 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1704 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1709 pub struct VariantDef {
1710 /// The variant's DefId. If this is a tuple-like struct,
1711 /// this is the DefId of the struct's ctor.
1713 pub name: Name, // struct's name if this is a struct
1714 pub discr: VariantDiscr,
1715 pub fields: Vec<FieldDef>,
1716 pub ctor_kind: CtorKind,
1717 flags: VariantFlags,
1720 impl<'a, 'gcx, 'tcx> VariantDef {
1721 /// Create a new `VariantDef`.
1723 /// - `did` is the DefId used for the variant - for tuple-structs, it is the constructor DefId,
1724 /// and for everything else, it is the variant DefId.
1725 /// - `attribute_def_id` is the DefId that has the variant's attributes.
1726 /// this is the struct DefId for structs, and the variant DefId for variants.
1728 /// Note that we *could* use the constructor DefId, because the constructor attributes
1729 /// redirect to the base attributes, but compiling a small crate requires
1730 /// loading the AdtDefs for all the structs in the universe (e.g. coherence for any
1731 /// built-in trait), and we do not want to load attributes twice.
1733 /// If someone speeds up attribute loading to not be a performance concern, they can
1734 /// remove this hack and use the constructor DefId everywhere.
1735 pub fn new(tcx: TyCtxt<'a, 'gcx, 'tcx>,
1738 discr: VariantDiscr,
1739 fields: Vec<FieldDef>,
1741 ctor_kind: CtorKind,
1742 attribute_def_id: DefId)
1745 debug!("VariantDef::new({:?}, {:?}, {:?}, {:?}, {:?}, {:?}, {:?})", did, name, discr,
1746 fields, adt_kind, ctor_kind, attribute_def_id);
1747 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1748 if adt_kind == AdtKind::Struct && tcx.has_attr(attribute_def_id, "non_exhaustive") {
1749 debug!("found non-exhaustive field list for {:?}", did);
1750 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1763 pub fn is_field_list_non_exhaustive(&self) -> bool {
1764 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1768 impl_stable_hash_for!(struct VariantDef {
1777 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1778 pub enum VariantDiscr {
1779 /// Explicit value for this variant, i.e. `X = 123`.
1780 /// The `DefId` corresponds to the embedded constant.
1783 /// The previous variant's discriminant plus one.
1784 /// For efficiency reasons, the distance from the
1785 /// last `Explicit` discriminant is being stored,
1786 /// or `0` for the first variant, if it has none.
1791 pub struct FieldDef {
1794 pub vis: Visibility,
1797 /// The definition of an abstract data type - a struct or enum.
1799 /// These are all interned (by intern_adt_def) into the adt_defs
1803 pub variants: Vec<VariantDef>,
1805 pub repr: ReprOptions,
1808 impl PartialOrd for AdtDef {
1809 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1810 Some(self.cmp(&other))
1814 /// There should be only one AdtDef for each `did`, therefore
1815 /// it is fine to implement `Ord` only based on `did`.
1816 impl Ord for AdtDef {
1817 fn cmp(&self, other: &AdtDef) -> Ordering {
1818 self.did.cmp(&other.did)
1822 impl PartialEq for AdtDef {
1823 // AdtDef are always interned and this is part of TyS equality
1825 fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) }
1828 impl Eq for AdtDef {}
1830 impl Hash for AdtDef {
1832 fn hash<H: Hasher>(&self, s: &mut H) {
1833 (self as *const AdtDef).hash(s)
1837 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1838 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1843 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1846 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1847 fn hash_stable<W: StableHasherResult>(&self,
1848 hcx: &mut StableHashingContext<'a>,
1849 hasher: &mut StableHasher<W>) {
1851 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> = Default::default();
1854 let hash: Fingerprint = CACHE.with(|cache| {
1855 let addr = self as *const AdtDef as usize;
1856 *cache.borrow_mut().entry(addr).or_insert_with(|| {
1864 let mut hasher = StableHasher::new();
1865 did.hash_stable(hcx, &mut hasher);
1866 variants.hash_stable(hcx, &mut hasher);
1867 flags.hash_stable(hcx, &mut hasher);
1868 repr.hash_stable(hcx, &mut hasher);
1874 hash.hash_stable(hcx, hasher);
1878 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
1879 pub enum AdtKind { Struct, Union, Enum }
1881 impl Into<DataTypeKind> for AdtKind {
1882 fn into(self) -> DataTypeKind {
1884 AdtKind::Struct => DataTypeKind::Struct,
1885 AdtKind::Union => DataTypeKind::Union,
1886 AdtKind::Enum => DataTypeKind::Enum,
1892 #[derive(RustcEncodable, RustcDecodable, Default)]
1893 pub struct ReprFlags: u8 {
1894 const IS_C = 1 << 0;
1895 const IS_SIMD = 1 << 1;
1896 const IS_TRANSPARENT = 1 << 2;
1897 // Internal only for now. If true, don't reorder fields.
1898 const IS_LINEAR = 1 << 3;
1900 // Any of these flags being set prevent field reordering optimisation.
1901 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1902 ReprFlags::IS_SIMD.bits |
1903 ReprFlags::IS_LINEAR.bits;
1907 impl_stable_hash_for!(struct ReprFlags {
1913 /// Represents the repr options provided by the user,
1914 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1915 pub struct ReprOptions {
1916 pub int: Option<attr::IntType>,
1919 pub flags: ReprFlags,
1922 impl_stable_hash_for!(struct ReprOptions {
1930 pub fn new(tcx: TyCtxt<'_, '_, '_>, did: DefId) -> ReprOptions {
1931 let mut flags = ReprFlags::empty();
1932 let mut size = None;
1933 let mut max_align = 0;
1934 let mut min_pack = 0;
1935 for attr in tcx.get_attrs(did).iter() {
1936 for r in attr::find_repr_attrs(&tcx.sess.parse_sess, attr) {
1937 flags.insert(match r {
1938 attr::ReprC => ReprFlags::IS_C,
1939 attr::ReprPacked(pack) => {
1940 min_pack = if min_pack > 0 {
1941 cmp::min(pack, min_pack)
1947 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
1948 attr::ReprSimd => ReprFlags::IS_SIMD,
1949 attr::ReprInt(i) => {
1953 attr::ReprAlign(align) => {
1954 max_align = cmp::max(align, max_align);
1961 // This is here instead of layout because the choice must make it into metadata.
1962 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1963 flags.insert(ReprFlags::IS_LINEAR);
1965 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
1969 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1971 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1973 pub fn packed(&self) -> bool { self.pack > 0 }
1975 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
1977 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1979 pub fn discr_type(&self) -> attr::IntType {
1980 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
1983 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
1984 /// layout" optimizations, such as representing `Foo<&T>` as a
1986 pub fn inhibit_enum_layout_opt(&self) -> bool {
1987 self.c() || self.int.is_some()
1990 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
1991 /// optimizations, such as with repr(C) or repr(packed(1)).
1992 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
1993 !(self.flags & ReprFlags::IS_UNOPTIMISABLE).is_empty() || (self.pack == 1)
1997 impl<'a, 'gcx, 'tcx> AdtDef {
1998 fn new(tcx: TyCtxt<'_, '_, '_>,
2001 variants: Vec<VariantDef>,
2002 repr: ReprOptions) -> Self {
2003 debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
2004 let mut flags = AdtFlags::NO_ADT_FLAGS;
2005 let attrs = tcx.get_attrs(did);
2006 if attr::contains_name(&attrs, "fundamental") {
2007 flags = flags | AdtFlags::IS_FUNDAMENTAL;
2009 if Some(did) == tcx.lang_items().phantom_data() {
2010 flags = flags | AdtFlags::IS_PHANTOM_DATA;
2012 if Some(did) == tcx.lang_items().owned_box() {
2013 flags = flags | AdtFlags::IS_BOX;
2015 if Some(did) == tcx.lang_items().arc() {
2016 flags = flags | AdtFlags::IS_ARC;
2018 if Some(did) == tcx.lang_items().rc() {
2019 flags = flags | AdtFlags::IS_RC;
2021 if kind == AdtKind::Enum && tcx.has_attr(did, "non_exhaustive") {
2022 debug!("found non-exhaustive variant list for {:?}", did);
2023 flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
2026 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
2027 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
2028 AdtKind::Struct => {}
2039 pub fn is_struct(&self) -> bool {
2040 !self.is_union() && !self.is_enum()
2044 pub fn is_union(&self) -> bool {
2045 self.flags.intersects(AdtFlags::IS_UNION)
2049 pub fn is_enum(&self) -> bool {
2050 self.flags.intersects(AdtFlags::IS_ENUM)
2054 pub fn is_variant_list_non_exhaustive(&self) -> bool {
2055 self.flags.intersects(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
2058 /// Returns the kind of the ADT - Struct or Enum.
2060 pub fn adt_kind(&self) -> AdtKind {
2063 } else if self.is_union() {
2070 pub fn descr(&self) -> &'static str {
2071 match self.adt_kind() {
2072 AdtKind::Struct => "struct",
2073 AdtKind::Union => "union",
2074 AdtKind::Enum => "enum",
2078 pub fn variant_descr(&self) -> &'static str {
2079 match self.adt_kind() {
2080 AdtKind::Struct => "struct",
2081 AdtKind::Union => "union",
2082 AdtKind::Enum => "variant",
2086 /// Returns whether this type is #[fundamental] for the purposes
2087 /// of coherence checking.
2089 pub fn is_fundamental(&self) -> bool {
2090 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
2093 /// Returns `true` if this is PhantomData<T>.
2095 pub fn is_phantom_data(&self) -> bool {
2096 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
2099 /// Returns `true` if this is `Arc<T>`.
2100 pub fn is_arc(&self) -> bool {
2101 self.flags.intersects(AdtFlags::IS_ARC)
2104 /// Returns `true` if this is `Rc<T>`.
2105 pub fn is_rc(&self) -> bool {
2106 self.flags.intersects(AdtFlags::IS_RC)
2109 /// Returns `true` if this is Box<T>.
2111 pub fn is_box(&self) -> bool {
2112 self.flags.intersects(AdtFlags::IS_BOX)
2115 /// Returns whether this type has a destructor.
2116 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
2117 self.destructor(tcx).is_some()
2120 /// Asserts this is a struct or union and returns its unique variant.
2121 pub fn non_enum_variant(&self) -> &VariantDef {
2122 assert!(self.is_struct() || self.is_union());
2127 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
2128 tcx.predicates_of(self.did)
2131 /// Returns an iterator over all fields contained
2134 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
2135 self.variants.iter().flat_map(|v| v.fields.iter())
2138 pub fn is_payloadfree(&self) -> bool {
2139 !self.variants.is_empty() &&
2140 self.variants.iter().all(|v| v.fields.is_empty())
2143 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
2146 .find(|v| v.did == vid)
2147 .expect("variant_with_id: unknown variant")
2150 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
2153 .position(|v| v.did == vid)
2154 .expect("variant_index_with_id: unknown variant")
2157 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
2159 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
2160 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
2161 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) |
2162 Def::SelfCtor(..) => self.non_enum_variant(),
2163 _ => bug!("unexpected def {:?} in variant_of_def", def)
2168 pub fn eval_explicit_discr(
2170 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2172 ) -> Option<Discr<'tcx>> {
2173 let param_env = ParamEnv::empty();
2174 let repr_type = self.repr.discr_type();
2175 let substs = Substs::identity_for_item(tcx.global_tcx(), expr_did);
2176 let instance = ty::Instance::new(expr_did, substs);
2177 let cid = GlobalId {
2181 match tcx.const_eval(param_env.and(cid)) {
2183 // FIXME: Find the right type and use it instead of `val.ty` here
2184 if let Some(b) = val.assert_bits(tcx.global_tcx(), param_env.and(val.ty)) {
2185 trace!("discriminants: {} ({:?})", b, repr_type);
2191 info!("invalid enum discriminant: {:#?}", val);
2192 ::mir::interpret::struct_error(
2193 tcx.at(tcx.def_span(expr_did)),
2194 "constant evaluation of enum discriminant resulted in non-integer",
2199 Err(ErrorHandled::Reported) => {
2200 if !expr_did.is_local() {
2201 span_bug!(tcx.def_span(expr_did),
2202 "variant discriminant evaluation succeeded \
2203 in its crate but failed locally");
2207 Err(ErrorHandled::TooGeneric) => span_bug!(
2208 tcx.def_span(expr_did),
2209 "enum discriminant depends on generic arguments",
2215 pub fn discriminants(
2217 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2218 ) -> impl Iterator<Item=Discr<'tcx>> + Captures<'gcx> + 'a {
2219 let repr_type = self.repr.discr_type();
2220 let initial = repr_type.initial_discriminant(tcx.global_tcx());
2221 let mut prev_discr = None::<Discr<'tcx>>;
2222 self.variants.iter().map(move |v| {
2223 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
2224 if let VariantDiscr::Explicit(expr_did) = v.discr {
2225 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
2229 prev_discr = Some(discr);
2235 /// Compute the discriminant value used by a specific variant.
2236 /// Unlike `discriminants`, this is (amortized) constant-time,
2237 /// only doing at most one query for evaluating an explicit
2238 /// discriminant (the last one before the requested variant),
2239 /// assuming there are no constant-evaluation errors there.
2240 pub fn discriminant_for_variant(&self,
2241 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2242 variant_index: usize)
2244 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2245 let explicit_value = val
2246 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2247 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx.global_tcx()));
2248 explicit_value.checked_add(tcx, offset as u128).0
2251 /// Yields a DefId for the discriminant and an offset to add to it
2252 /// Alternatively, if there is no explicit discriminant, returns the
2253 /// inferred discriminant directly
2254 pub fn discriminant_def_for_variant(
2256 variant_index: usize,
2257 ) -> (Option<DefId>, usize) {
2258 let mut explicit_index = variant_index;
2261 match self.variants[explicit_index].discr {
2262 ty::VariantDiscr::Relative(0) => {
2266 ty::VariantDiscr::Relative(distance) => {
2267 explicit_index -= distance;
2269 ty::VariantDiscr::Explicit(did) => {
2270 expr_did = Some(did);
2275 (expr_did, variant_index - explicit_index)
2278 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
2279 tcx.adt_destructor(self.did)
2282 /// Returns a list of types such that `Self: Sized` if and only
2283 /// if that type is Sized, or `TyErr` if this type is recursive.
2285 /// Oddly enough, checking that the sized-constraint is Sized is
2286 /// actually more expressive than checking all members:
2287 /// the Sized trait is inductive, so an associated type that references
2288 /// Self would prevent its containing ADT from being Sized.
2290 /// Due to normalization being eager, this applies even if
2291 /// the associated type is behind a pointer, e.g. issue #31299.
2292 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
2293 match tcx.try_adt_sized_constraint(DUMMY_SP, self.did) {
2296 debug!("adt_sized_constraint: {:?} is recursive", self);
2297 // This should be reported as an error by `check_representable`.
2299 // Consider the type as Sized in the meanwhile to avoid
2300 // further errors. Delay our `bug` diagnostic here to get
2301 // emitted later as well in case we accidentally otherwise don't
2304 tcx.intern_type_list(&[tcx.types.err])
2309 fn sized_constraint_for_ty(&self,
2310 tcx: TyCtxt<'a, 'tcx, 'tcx>,
2313 let result = match ty.sty {
2314 Bool | Char | Int(..) | Uint(..) | Float(..) |
2315 RawPtr(..) | Ref(..) | FnDef(..) | FnPtr(_) |
2316 Array(..) | Closure(..) | Generator(..) | Never => {
2325 GeneratorWitness(..) => {
2326 // these are never sized - return the target type
2333 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
2337 Adt(adt, substs) => {
2339 let adt_tys = adt.sized_constraint(tcx);
2340 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
2343 .map(|ty| ty.subst(tcx, substs))
2344 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2348 Projection(..) | Opaque(..) => {
2349 // must calculate explicitly.
2350 // FIXME: consider special-casing always-Sized projections
2354 UnnormalizedProjection(..) => bug!("only used with chalk-engine"),
2357 // perf hack: if there is a `T: Sized` bound, then
2358 // we know that `T` is Sized and do not need to check
2361 let sized_trait = match tcx.lang_items().sized_trait() {
2363 _ => return vec![ty]
2365 let sized_predicate = Binder::dummy(TraitRef {
2366 def_id: sized_trait,
2367 substs: tcx.mk_substs_trait(ty, &[])
2369 let predicates = tcx.predicates_of(self.did).predicates;
2370 if predicates.into_iter().any(|(p, _)| p == sized_predicate) {
2379 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2383 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2388 impl<'a, 'gcx, 'tcx> FieldDef {
2389 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
2390 tcx.type_of(self.did).subst(tcx, subst)
2394 /// Represents the various closure traits in the Rust language. This
2395 /// will determine the type of the environment (`self`, in the
2396 /// desuaring) argument that the closure expects.
2398 /// You can get the environment type of a closure using
2399 /// `tcx.closure_env_ty()`.
2400 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
2401 pub enum ClosureKind {
2402 // Warning: Ordering is significant here! The ordering is chosen
2403 // because the trait Fn is a subtrait of FnMut and so in turn, and
2404 // hence we order it so that Fn < FnMut < FnOnce.
2410 impl<'a, 'tcx> ClosureKind {
2411 // This is the initial value used when doing upvar inference.
2412 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2414 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
2416 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
2417 ClosureKind::FnMut => {
2418 tcx.require_lang_item(FnMutTraitLangItem)
2420 ClosureKind::FnOnce => {
2421 tcx.require_lang_item(FnOnceTraitLangItem)
2426 /// Returns `true` if this a type that impls this closure kind
2427 /// must also implement `other`.
2428 pub fn extends(self, other: ty::ClosureKind) -> bool {
2429 match (self, other) {
2430 (ClosureKind::Fn, ClosureKind::Fn) => true,
2431 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2432 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2433 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2434 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2435 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2440 /// Returns the representative scalar type for this closure kind.
2441 /// See `TyS::to_opt_closure_kind` for more details.
2442 pub fn to_ty(self, tcx: TyCtxt<'_, '_, 'tcx>) -> Ty<'tcx> {
2444 ty::ClosureKind::Fn => tcx.types.i8,
2445 ty::ClosureKind::FnMut => tcx.types.i16,
2446 ty::ClosureKind::FnOnce => tcx.types.i32,
2451 impl<'tcx> TyS<'tcx> {
2452 /// Iterator that walks `self` and any types reachable from
2453 /// `self`, in depth-first order. Note that just walks the types
2454 /// that appear in `self`, it does not descend into the fields of
2455 /// structs or variants. For example:
2458 /// isize => { isize }
2459 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2460 /// [isize] => { [isize], isize }
2462 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2463 TypeWalker::new(self)
2466 /// Iterator that walks the immediate children of `self`. Hence
2467 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2468 /// (but not `i32`, like `walk`).
2469 pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
2470 walk::walk_shallow(self)
2473 /// Walks `ty` and any types appearing within `ty`, invoking the
2474 /// callback `f` on each type. If the callback returns false, then the
2475 /// children of the current type are ignored.
2477 /// Note: prefer `ty.walk()` where possible.
2478 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2479 where F : FnMut(Ty<'tcx>) -> bool
2481 let mut walker = self.walk();
2482 while let Some(ty) = walker.next() {
2484 walker.skip_current_subtree();
2491 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2493 hir::MutMutable => MutBorrow,
2494 hir::MutImmutable => ImmBorrow,
2498 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2499 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2500 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2502 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2504 MutBorrow => hir::MutMutable,
2505 ImmBorrow => hir::MutImmutable,
2507 // We have no type corresponding to a unique imm borrow, so
2508 // use `&mut`. It gives all the capabilities of an `&uniq`
2509 // and hence is a safe "over approximation".
2510 UniqueImmBorrow => hir::MutMutable,
2514 pub fn to_user_str(&self) -> &'static str {
2516 MutBorrow => "mutable",
2517 ImmBorrow => "immutable",
2518 UniqueImmBorrow => "uniquely immutable",
2523 #[derive(Debug, Clone)]
2524 pub enum Attributes<'gcx> {
2525 Owned(Lrc<[ast::Attribute]>),
2526 Borrowed(&'gcx [ast::Attribute])
2529 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2530 type Target = [ast::Attribute];
2532 fn deref(&self) -> &[ast::Attribute] {
2534 &Attributes::Owned(ref data) => &data,
2535 &Attributes::Borrowed(data) => data
2540 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2541 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2542 self.typeck_tables_of(self.hir.body_owner_def_id(body))
2545 /// Returns an iterator of the def-ids for all body-owners in this
2546 /// crate. If you would prefer to iterate over the bodies
2547 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
2550 ) -> impl Iterator<Item = DefId> + Captures<'tcx> + Captures<'gcx> + 'a {
2554 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
2557 pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
2558 par_iter(&self.hir.krate().body_ids).for_each(|&body_id| {
2559 f(self.hir.body_owner_def_id(body_id))
2563 pub fn expr_span(self, id: NodeId) -> Span {
2564 match self.hir.find(id) {
2565 Some(Node::Expr(e)) => {
2569 bug!("Node id {} is not an expr: {:?}", id, f);
2572 bug!("Node id {} is not present in the node map", id);
2577 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2578 self.associated_items(id)
2579 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2583 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2584 self.associated_items(did).any(|item| {
2585 item.relevant_for_never()
2589 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2590 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2591 match self.hir.get(node_id) {
2592 Node::TraitItem(_) | Node::ImplItem(_) => true,
2596 match self.describe_def(def_id).expect("no def for def-id") {
2597 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2602 if is_associated_item {
2603 Some(self.associated_item(def_id))
2609 fn associated_item_from_trait_item_ref(self,
2610 parent_def_id: DefId,
2611 parent_vis: &hir::Visibility,
2612 trait_item_ref: &hir::TraitItemRef)
2614 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2615 let (kind, has_self) = match trait_item_ref.kind {
2616 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2617 hir::AssociatedItemKind::Method { has_self } => {
2618 (ty::AssociatedKind::Method, has_self)
2620 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2621 hir::AssociatedItemKind::Existential => bug!("only impls can have existentials"),
2625 ident: trait_item_ref.ident,
2627 // Visibility of trait items is inherited from their traits.
2628 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2629 defaultness: trait_item_ref.defaultness,
2631 container: TraitContainer(parent_def_id),
2632 method_has_self_argument: has_self
2636 fn associated_item_from_impl_item_ref(self,
2637 parent_def_id: DefId,
2638 impl_item_ref: &hir::ImplItemRef)
2640 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2641 let (kind, has_self) = match impl_item_ref.kind {
2642 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2643 hir::AssociatedItemKind::Method { has_self } => {
2644 (ty::AssociatedKind::Method, has_self)
2646 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2647 hir::AssociatedItemKind::Existential => (ty::AssociatedKind::Existential, false),
2651 ident: impl_item_ref.ident,
2653 // Visibility of trait impl items doesn't matter.
2654 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2655 defaultness: impl_item_ref.defaultness,
2657 container: ImplContainer(parent_def_id),
2658 method_has_self_argument: has_self
2662 pub fn field_index(self, node_id: NodeId, tables: &TypeckTables<'_>) -> usize {
2663 let hir_id = self.hir.node_to_hir_id(node_id);
2664 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2667 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2668 variant.fields.iter().position(|field| {
2669 self.adjust_ident(ident, variant.did, DUMMY_NODE_ID).0 == field.ident.modern()
2673 pub fn associated_items(
2676 ) -> impl Iterator<Item = AssociatedItem> + 'a {
2677 let def_ids = self.associated_item_def_ids(def_id);
2678 Box::new((0..def_ids.len()).map(move |i| self.associated_item(def_ids[i])))
2679 as Box<dyn Iterator<Item = AssociatedItem> + 'a>
2682 /// Returns `true` if the impls are the same polarity and the trait either
2683 /// has no items or is annotated #[marker] and prevents item overrides.
2684 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2685 if self.features().overlapping_marker_traits {
2686 let trait1_is_empty = self.impl_trait_ref(def_id1)
2687 .map_or(false, |trait_ref| {
2688 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2690 let trait2_is_empty = self.impl_trait_ref(def_id2)
2691 .map_or(false, |trait_ref| {
2692 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2694 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2697 } else if self.features().marker_trait_attr {
2698 let is_marker_impl = |def_id: DefId| -> bool {
2699 let trait_ref = self.impl_trait_ref(def_id);
2700 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2702 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2703 && is_marker_impl(def_id1)
2704 && is_marker_impl(def_id2)
2710 // Returns `ty::VariantDef` if `def` refers to a struct,
2711 // or variant or their constructors, panics otherwise.
2712 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2714 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2715 let enum_did = self.parent_def_id(did).unwrap();
2716 self.adt_def(enum_did).variant_with_id(did)
2718 Def::Struct(did) | Def::Union(did) => {
2719 self.adt_def(did).non_enum_variant()
2721 Def::StructCtor(ctor_did, ..) => {
2722 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2723 self.adt_def(did).non_enum_variant()
2725 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2729 /// Given a `VariantDef`, returns the def-id of the `AdtDef` of which it is a part.
2730 pub fn adt_def_id_of_variant(self, variant_def: &'tcx VariantDef) -> DefId {
2731 let def_key = self.def_key(variant_def.did);
2732 match def_key.disambiguated_data.data {
2733 // for enum variants and tuple structs, the def-id of the ADT itself
2734 // is the *parent* of the variant
2735 DefPathData::EnumVariant(..) | DefPathData::StructCtor =>
2736 DefId { krate: variant_def.did.krate, index: def_key.parent.unwrap() },
2738 // otherwise, for structs and unions, they share a def-id
2739 _ => variant_def.did,
2743 pub fn item_name(self, id: DefId) -> InternedString {
2744 if id.index == CRATE_DEF_INDEX {
2745 self.original_crate_name(id.krate).as_interned_str()
2747 let def_key = self.def_key(id);
2748 // The name of a StructCtor is that of its struct parent.
2749 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2750 self.item_name(DefId {
2752 index: def_key.parent.unwrap()
2755 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2756 bug!("item_name: no name for {:?}", self.def_path(id));
2762 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2763 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2767 ty::InstanceDef::Item(did) => {
2768 self.optimized_mir(did)
2770 ty::InstanceDef::VtableShim(..) |
2771 ty::InstanceDef::Intrinsic(..) |
2772 ty::InstanceDef::FnPtrShim(..) |
2773 ty::InstanceDef::Virtual(..) |
2774 ty::InstanceDef::ClosureOnceShim { .. } |
2775 ty::InstanceDef::DropGlue(..) |
2776 ty::InstanceDef::CloneShim(..) => {
2777 self.mir_shims(instance)
2782 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2783 /// Returns None if there is no MIR for the DefId
2784 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2785 if self.is_mir_available(did) {
2786 Some(self.optimized_mir(did))
2792 /// Get the attributes of a definition.
2793 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2794 if let Some(id) = self.hir.as_local_node_id(did) {
2795 Attributes::Borrowed(self.hir.attrs(id))
2797 Attributes::Owned(self.item_attrs(did))
2801 /// Determine whether an item is annotated with an attribute.
2802 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2803 attr::contains_name(&self.get_attrs(did), attr)
2806 /// Returns `true` if this is an `auto trait`.
2807 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
2808 self.trait_def(trait_def_id).has_auto_impl
2811 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
2812 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
2815 /// Given the def-id of an impl, return the def_id of the trait it implements.
2816 /// If it implements no trait, return `None`.
2817 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2818 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2821 /// If the given defid describes a method belonging to an impl, return the
2822 /// def-id of the impl that the method belongs to. Otherwise, return `None`.
2823 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2824 let item = if def_id.krate != LOCAL_CRATE {
2825 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2826 Some(self.associated_item(def_id))
2831 self.opt_associated_item(def_id)
2834 item.and_then(|trait_item|
2835 match trait_item.container {
2836 TraitContainer(_) => None,
2837 ImplContainer(def_id) => Some(def_id),
2842 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2843 /// with the name of the crate containing the impl.
2844 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2845 if impl_did.is_local() {
2846 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2847 Ok(self.hir.span(node_id))
2849 Err(self.crate_name(impl_did.krate))
2853 // Hygienically compare a use-site name (`use_name`) for a field or an associated item with its
2854 // supposed definition name (`def_name`). The method also needs `DefId` of the supposed
2855 // definition's parent/scope to perform comparison.
2856 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
2857 self.adjust_ident(use_name, def_parent_def_id, DUMMY_NODE_ID).0 == def_name.modern()
2860 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
2861 ident = ident.modern();
2862 let target_expansion = match scope.krate {
2863 LOCAL_CRATE => self.hir.definitions().expansion_that_defined(scope.index),
2866 let scope = match ident.span.adjust(target_expansion) {
2867 Some(actual_expansion) =>
2868 self.hir.definitions().parent_module_of_macro_def(actual_expansion),
2869 None if block == DUMMY_NODE_ID => DefId::local(CRATE_DEF_INDEX), // Dummy DefId
2870 None => self.hir.get_module_parent(block),
2876 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2877 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2878 F: FnOnce(&[hir::Freevar]) -> T,
2880 let def_id = self.hir.local_def_id(fid);
2881 match self.freevars(def_id) {
2888 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> AssociatedItem {
2889 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2890 let parent_id = tcx.hir.get_parent(id);
2891 let parent_def_id = tcx.hir.local_def_id(parent_id);
2892 let parent_item = tcx.hir.expect_item(parent_id);
2893 match parent_item.node {
2894 hir::ItemKind::Impl(.., ref impl_item_refs) => {
2895 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2896 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2898 debug_assert_eq!(assoc_item.def_id, def_id);
2903 hir::ItemKind::Trait(.., ref trait_item_refs) => {
2904 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2905 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2908 debug_assert_eq!(assoc_item.def_id, def_id);
2916 span_bug!(parent_item.span,
2917 "unexpected parent of trait or impl item or item not found: {:?}",
2921 /// Calculates the Sized-constraint.
2923 /// In fact, there are only a few options for the types in the constraint:
2924 /// - an obviously-unsized type
2925 /// - a type parameter or projection whose Sizedness can't be known
2926 /// - a tuple of type parameters or projections, if there are multiple
2928 /// - a Error, if a type contained itself. The representability
2929 /// check should catch this case.
2930 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2932 -> &'tcx [Ty<'tcx>] {
2933 let def = tcx.adt_def(def_id);
2935 let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| {
2938 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2941 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2946 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2948 -> Lrc<Vec<DefId>> {
2949 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2950 let item = tcx.hir.expect_item(id);
2951 let vec: Vec<_> = match item.node {
2952 hir::ItemKind::Trait(.., ref trait_item_refs) => {
2953 trait_item_refs.iter()
2954 .map(|trait_item_ref| trait_item_ref.id)
2955 .map(|id| tcx.hir.local_def_id(id.node_id))
2958 hir::ItemKind::Impl(.., ref impl_item_refs) => {
2959 impl_item_refs.iter()
2960 .map(|impl_item_ref| impl_item_ref.id)
2961 .map(|id| tcx.hir.local_def_id(id.node_id))
2964 hir::ItemKind::TraitAlias(..) => vec![],
2965 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2970 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
2971 tcx.hir.span_if_local(def_id).unwrap()
2974 /// If the given def ID describes an item belonging to a trait,
2975 /// return the ID of the trait that the trait item belongs to.
2976 /// Otherwise, return `None`.
2977 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
2978 tcx.opt_associated_item(def_id)
2979 .and_then(|associated_item| {
2980 match associated_item.container {
2981 TraitContainer(def_id) => Some(def_id),
2982 ImplContainer(_) => None
2987 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
2988 pub fn is_impl_trait_defn(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> Option<DefId> {
2989 if let Some(node_id) = tcx.hir.as_local_node_id(def_id) {
2990 if let Node::Item(item) = tcx.hir.get(node_id) {
2991 if let hir::ItemKind::Existential(ref exist_ty) = item.node {
2992 return exist_ty.impl_trait_fn;
2999 /// Returns `true` if `def_id` is a trait alias.
3000 pub fn is_trait_alias(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> bool {
3001 if let Some(node_id) = tcx.hir.as_local_node_id(def_id) {
3002 if let Node::Item(item) = tcx.hir.get(node_id) {
3003 if let hir::ItemKind::TraitAlias(..) = item.node {
3011 /// See `ParamEnv` struct definition for details.
3012 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3016 // The param_env of an impl Trait type is its defining function's param_env
3017 if let Some(parent) = is_impl_trait_defn(tcx, def_id) {
3018 return param_env(tcx, parent);
3020 // Compute the bounds on Self and the type parameters.
3022 let InstantiatedPredicates { predicates } =
3023 tcx.predicates_of(def_id).instantiate_identity(tcx);
3025 // Finally, we have to normalize the bounds in the environment, in
3026 // case they contain any associated type projections. This process
3027 // can yield errors if the put in illegal associated types, like
3028 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
3029 // report these errors right here; this doesn't actually feel
3030 // right to me, because constructing the environment feels like a
3031 // kind of a "idempotent" action, but I'm not sure where would be
3032 // a better place. In practice, we construct environments for
3033 // every fn once during type checking, and we'll abort if there
3034 // are any errors at that point, so after type checking you can be
3035 // sure that this will succeed without errors anyway.
3037 let unnormalized_env = ty::ParamEnv::new(tcx.intern_predicates(&predicates),
3038 traits::Reveal::UserFacing);
3040 let body_id = tcx.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
3041 tcx.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_id)
3043 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
3044 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
3047 fn crate_disambiguator<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3048 crate_num: CrateNum) -> CrateDisambiguator {
3049 assert_eq!(crate_num, LOCAL_CRATE);
3050 tcx.sess.local_crate_disambiguator()
3053 fn original_crate_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3054 crate_num: CrateNum) -> Symbol {
3055 assert_eq!(crate_num, LOCAL_CRATE);
3056 tcx.crate_name.clone()
3059 fn crate_hash<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3060 crate_num: CrateNum)
3062 assert_eq!(crate_num, LOCAL_CRATE);
3066 fn instance_def_size_estimate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3067 instance_def: InstanceDef<'tcx>)
3069 match instance_def {
3070 InstanceDef::Item(..) |
3071 InstanceDef::DropGlue(..) => {
3072 let mir = tcx.instance_mir(instance_def);
3073 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
3075 // Estimate the size of other compiler-generated shims to be 1.
3080 pub fn provide(providers: &mut ty::query::Providers<'_>) {
3081 context::provide(providers);
3082 erase_regions::provide(providers);
3083 layout::provide(providers);
3084 util::provide(providers);
3085 constness::provide(providers);
3086 *providers = ty::query::Providers {
3088 associated_item_def_ids,
3089 adt_sized_constraint,
3093 crate_disambiguator,
3094 original_crate_name,
3096 trait_impls_of: trait_def::trait_impls_of_provider,
3097 instance_def_size_estimate,
3102 /// A map for the local crate mapping each type to a vector of its
3103 /// inherent impls. This is not meant to be used outside of coherence;
3104 /// rather, you should request the vector for a specific type via
3105 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
3106 /// (constructing this map requires touching the entire crate).
3107 #[derive(Clone, Debug)]
3108 pub struct CrateInherentImpls {
3109 pub inherent_impls: DefIdMap<Lrc<Vec<DefId>>>,
3112 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
3113 pub struct SymbolName {
3114 // FIXME: we don't rely on interning or equality here - better have
3115 // this be a `&'tcx str`.
3116 pub name: InternedString
3119 impl_stable_hash_for!(struct self::SymbolName {
3124 pub fn new(name: &str) -> SymbolName {
3126 name: Symbol::intern(name).as_interned_str()
3130 pub fn as_str(&self) -> LocalInternedString {
3135 impl fmt::Display for SymbolName {
3136 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3137 fmt::Display::fmt(&self.name, fmt)
3141 impl fmt::Debug for SymbolName {
3142 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3143 fmt::Display::fmt(&self.name, fmt)