1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 pub use self::Variance::*;
12 pub use self::AssociatedItemContainer::*;
13 pub use self::BorrowKind::*;
14 pub use self::IntVarValue::*;
15 pub use self::fold::TypeFoldable;
17 use hir::{map as hir_map, FreevarMap, TraitMap};
19 use hir::def::{Def, CtorKind, ExportMap};
20 use hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
21 use hir::map::DefPathData;
22 use rustc_data_structures::svh::Svh;
24 use ich::StableHashingContext;
25 use infer::canonical::Canonical;
26 use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
27 use middle::privacy::AccessLevels;
28 use middle::resolve_lifetime::ObjectLifetimeDefault;
30 use mir::interpret::GlobalId;
31 use mir::GeneratorLayout;
32 use session::CrateDisambiguator;
33 use traits::{self, Reveal};
35 use ty::subst::{Subst, Substs};
36 use ty::util::{IntTypeExt, Discr};
37 use ty::walk::TypeWalker;
38 use util::captures::Captures;
39 use util::nodemap::{NodeSet, DefIdMap, FxHashMap};
40 use arena::SyncDroplessArena;
41 use session::DataTypeKind;
43 use serialize::{self, Encodable, Encoder};
44 use std::cell::RefCell;
45 use std::cmp::{self, Ordering};
47 use std::hash::{Hash, Hasher};
49 use rustc_data_structures::sync::{self, Lrc, ParallelIterator, par_iter};
51 use std::vec::IntoIter;
53 use syntax::ast::{self, DUMMY_NODE_ID, Name, Ident, NodeId};
55 use syntax::ext::hygiene::Mark;
56 use syntax::symbol::{keywords, Symbol, LocalInternedString, InternedString};
57 use syntax_pos::{DUMMY_SP, Span};
60 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
65 pub use self::sty::{Binder, CanonicalVar, DebruijnIndex, INNERMOST};
66 pub use self::sty::{FnSig, GenSig, PolyFnSig, PolyGenSig};
67 pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
68 pub use self::sty::{ClosureSubsts, GeneratorSubsts, UpvarSubsts, TypeAndMut};
69 pub use self::sty::{TraitRef, TyKind, PolyTraitRef};
70 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
71 pub use self::sty::{ExistentialProjection, PolyExistentialProjection, Const};
72 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
73 pub use self::sty::RegionKind;
74 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid};
75 pub use self::sty::BoundRegion::*;
76 pub use self::sty::InferTy::*;
77 pub use self::sty::RegionKind::*;
78 pub use self::sty::TyKind::*;
80 pub use self::binding::BindingMode;
81 pub use self::binding::BindingMode::*;
83 pub use self::context::{TyCtxt, FreeRegionInfo, GlobalArenas, AllArenas, tls, keep_local};
84 pub use self::context::{Lift, TypeckTables};
86 pub use self::instance::{Instance, InstanceDef};
88 pub use self::trait_def::TraitDef;
90 pub use self::query::queries;
102 pub mod inhabitedness;
119 mod structural_impls;
124 /// The complete set of all analyses described in this module. This is
125 /// produced by the driver and fed to codegen and later passes.
127 /// NB: These contents are being migrated into queries using the
128 /// *on-demand* infrastructure.
130 pub struct CrateAnalysis {
131 pub access_levels: Lrc<AccessLevels>,
133 pub glob_map: Option<hir::GlobMap>,
137 pub struct Resolutions {
138 pub freevars: FreevarMap,
139 pub trait_map: TraitMap,
140 pub maybe_unused_trait_imports: NodeSet,
141 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
142 pub export_map: ExportMap,
145 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
146 pub enum AssociatedItemContainer {
147 TraitContainer(DefId),
148 ImplContainer(DefId),
151 impl AssociatedItemContainer {
152 /// Asserts that this is the def-id of an associated item declared
153 /// in a trait, and returns the trait def-id.
154 pub fn assert_trait(&self) -> DefId {
156 TraitContainer(id) => id,
157 _ => bug!("associated item has wrong container type: {:?}", self)
161 pub fn id(&self) -> DefId {
163 TraitContainer(id) => id,
164 ImplContainer(id) => id,
169 /// The "header" of an impl is everything outside the body: a Self type, a trait
170 /// ref (in the case of a trait impl), and a set of predicates (from the
171 /// bounds/where clauses).
172 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
173 pub struct ImplHeader<'tcx> {
174 pub impl_def_id: DefId,
175 pub self_ty: Ty<'tcx>,
176 pub trait_ref: Option<TraitRef<'tcx>>,
177 pub predicates: Vec<Predicate<'tcx>>,
180 #[derive(Copy, Clone, Debug, PartialEq)]
181 pub struct AssociatedItem {
184 pub kind: AssociatedKind,
186 pub defaultness: hir::Defaultness,
187 pub container: AssociatedItemContainer,
189 /// Whether this is a method with an explicit self
190 /// as its first argument, allowing method calls.
191 pub method_has_self_argument: bool,
194 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash, RustcEncodable, RustcDecodable)]
195 pub enum AssociatedKind {
202 impl AssociatedItem {
203 pub fn def(&self) -> Def {
205 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
206 AssociatedKind::Method => Def::Method(self.def_id),
207 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
208 AssociatedKind::Existential => Def::AssociatedExistential(self.def_id),
212 /// Tests whether the associated item admits a non-trivial implementation
214 pub fn relevant_for_never<'tcx>(&self) -> bool {
216 AssociatedKind::Existential |
217 AssociatedKind::Const |
218 AssociatedKind::Type => true,
219 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
220 AssociatedKind::Method => !self.method_has_self_argument,
224 pub fn signature<'a, 'tcx>(&self, tcx: &TyCtxt<'a, 'tcx, 'tcx>) -> String {
226 ty::AssociatedKind::Method => {
227 // We skip the binder here because the binder would deanonymize all
228 // late-bound regions, and we don't want method signatures to show up
229 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
230 // regions just fine, showing `fn(&MyType)`.
231 tcx.fn_sig(self.def_id).skip_binder().to_string()
233 ty::AssociatedKind::Type => format!("type {};", self.ident),
234 ty::AssociatedKind::Existential => format!("existential type {};", self.ident),
235 ty::AssociatedKind::Const => {
236 format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id))
242 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
243 pub enum Visibility {
244 /// Visible everywhere (including in other crates).
246 /// Visible only in the given crate-local module.
248 /// Not visible anywhere in the local crate. This is the visibility of private external items.
252 pub trait DefIdTree: Copy {
253 fn parent(self, id: DefId) -> Option<DefId>;
255 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
256 if descendant.krate != ancestor.krate {
260 while descendant != ancestor {
261 match self.parent(descendant) {
262 Some(parent) => descendant = parent,
263 None => return false,
270 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
271 fn parent(self, id: DefId) -> Option<DefId> {
272 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
277 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt<'_, '_, '_>) -> Self {
278 match visibility.node {
279 hir::VisibilityKind::Public => Visibility::Public,
280 hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
281 hir::VisibilityKind::Restricted { ref path, .. } => match path.def {
282 // If there is no resolution, `resolve` will have already reported an error, so
283 // assume that the visibility is public to avoid reporting more privacy errors.
284 Def::Err => Visibility::Public,
285 def => Visibility::Restricted(def.def_id()),
287 hir::VisibilityKind::Inherited => {
288 Visibility::Restricted(tcx.hir.get_module_parent(id))
293 /// Returns true if an item with this visibility is accessible from the given block.
294 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
295 let restriction = match self {
296 // Public items are visible everywhere.
297 Visibility::Public => return true,
298 // Private items from other crates are visible nowhere.
299 Visibility::Invisible => return false,
300 // Restricted items are visible in an arbitrary local module.
301 Visibility::Restricted(other) if other.krate != module.krate => return false,
302 Visibility::Restricted(module) => module,
305 tree.is_descendant_of(module, restriction)
308 /// Returns true if this visibility is at least as accessible as the given visibility
309 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
310 let vis_restriction = match vis {
311 Visibility::Public => return self == Visibility::Public,
312 Visibility::Invisible => return true,
313 Visibility::Restricted(module) => module,
316 self.is_accessible_from(vis_restriction, tree)
319 // Returns true if this item is visible anywhere in the local crate.
320 pub fn is_visible_locally(self) -> bool {
322 Visibility::Public => true,
323 Visibility::Restricted(def_id) => def_id.is_local(),
324 Visibility::Invisible => false,
329 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
331 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
332 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
333 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
334 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
337 /// The crate variances map is computed during typeck and contains the
338 /// variance of every item in the local crate. You should not use it
339 /// directly, because to do so will make your pass dependent on the
340 /// HIR of every item in the local crate. Instead, use
341 /// `tcx.variances_of()` to get the variance for a *particular*
343 pub struct CrateVariancesMap {
344 /// For each item with generics, maps to a vector of the variance
345 /// of its generics. If an item has no generics, it will have no
347 pub variances: FxHashMap<DefId, Lrc<Vec<ty::Variance>>>,
349 /// An empty vector, useful for cloning.
350 pub empty_variance: Lrc<Vec<ty::Variance>>,
354 /// `a.xform(b)` combines the variance of a context with the
355 /// variance of a type with the following meaning. If we are in a
356 /// context with variance `a`, and we encounter a type argument in
357 /// a position with variance `b`, then `a.xform(b)` is the new
358 /// variance with which the argument appears.
364 /// Here, the "ambient" variance starts as covariant. `*mut T` is
365 /// invariant with respect to `T`, so the variance in which the
366 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
367 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
368 /// respect to its type argument `T`, and hence the variance of
369 /// the `i32` here is `Invariant.xform(Covariant)`, which results
370 /// (again) in `Invariant`.
374 /// fn(*const Vec<i32>, *mut Vec<i32)
376 /// The ambient variance is covariant. A `fn` type is
377 /// contravariant with respect to its parameters, so the variance
378 /// within which both pointer types appear is
379 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
380 /// T` is covariant with respect to `T`, so the variance within
381 /// which the first `Vec<i32>` appears is
382 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
383 /// is true for its `i32` argument. In the `*mut T` case, the
384 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
385 /// and hence the outermost type is `Invariant` with respect to
386 /// `Vec<i32>` (and its `i32` argument).
388 /// Source: Figure 1 of "Taming the Wildcards:
389 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
390 pub fn xform(self, v: ty::Variance) -> ty::Variance {
392 // Figure 1, column 1.
393 (ty::Covariant, ty::Covariant) => ty::Covariant,
394 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
395 (ty::Covariant, ty::Invariant) => ty::Invariant,
396 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
398 // Figure 1, column 2.
399 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
400 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
401 (ty::Contravariant, ty::Invariant) => ty::Invariant,
402 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
404 // Figure 1, column 3.
405 (ty::Invariant, _) => ty::Invariant,
407 // Figure 1, column 4.
408 (ty::Bivariant, _) => ty::Bivariant,
413 // Contains information needed to resolve types and (in the future) look up
414 // the types of AST nodes.
415 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
416 pub struct CReaderCacheKey {
421 // Flags that we track on types. These flags are propagated upwards
422 // through the type during type construction, so that we can quickly
423 // check whether the type has various kinds of types in it without
424 // recursing over the type itself.
426 pub struct TypeFlags: u32 {
427 const HAS_PARAMS = 1 << 0;
428 const HAS_SELF = 1 << 1;
429 const HAS_TY_INFER = 1 << 2;
430 const HAS_RE_INFER = 1 << 3;
431 const HAS_RE_SKOL = 1 << 4;
433 /// Does this have any `ReEarlyBound` regions? Used to
434 /// determine whether substitition is required, since those
435 /// represent regions that are bound in a `ty::Generics` and
436 /// hence may be substituted.
437 const HAS_RE_EARLY_BOUND = 1 << 5;
439 /// Does this have any region that "appears free" in the type?
440 /// Basically anything but `ReLateBound` and `ReErased`.
441 const HAS_FREE_REGIONS = 1 << 6;
443 /// Is an error type reachable?
444 const HAS_TY_ERR = 1 << 7;
445 const HAS_PROJECTION = 1 << 8;
447 // FIXME: Rename this to the actual property since it's used for generators too
448 const HAS_TY_CLOSURE = 1 << 9;
450 // true if there are "names" of types and regions and so forth
451 // that are local to a particular fn
452 const HAS_FREE_LOCAL_NAMES = 1 << 10;
454 // Present if the type belongs in a local type context.
455 // Only set for Infer other than Fresh.
456 const KEEP_IN_LOCAL_TCX = 1 << 11;
458 // Is there a projection that does not involve a bound region?
459 // Currently we can't normalize projections w/ bound regions.
460 const HAS_NORMALIZABLE_PROJECTION = 1 << 12;
462 // Set if this includes a "canonical" type or region var --
463 // ought to be true only for the results of canonicalization.
464 const HAS_CANONICAL_VARS = 1 << 13;
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 << 14;
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_CANONICAL_VARS.bits |
490 TypeFlags::HAS_RE_LATE_BOUND.bits;
494 pub struct TyS<'tcx> {
495 pub sty: TyKind<'tcx>,
496 pub flags: TypeFlags,
498 /// This is a kind of confusing thing: it stores the smallest
501 /// (a) the binder itself captures nothing but
502 /// (b) all the late-bound things within the type are captured
503 /// by some sub-binder.
505 /// So, for a type without any late-bound things, like `u32`, this
506 /// will be INNERMOST, because that is the innermost binder that
507 /// captures nothing. But for a type `&'D u32`, where `'D` is a
508 /// late-bound region with debruijn index D, this would be D+1 --
509 /// the binder itself does not capture D, but D is captured by an
512 /// We call this concept an "exclusive" binder D (because all
513 /// debruijn indices within the type are contained within `0..D`
515 outer_exclusive_binder: ty::DebruijnIndex,
518 impl<'tcx> Ord for TyS<'tcx> {
519 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
520 self.sty.cmp(&other.sty)
524 impl<'tcx> PartialOrd for TyS<'tcx> {
525 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
526 Some(self.sty.cmp(&other.sty))
530 impl<'tcx> PartialEq for TyS<'tcx> {
532 fn eq(&self, other: &TyS<'tcx>) -> bool {
536 impl<'tcx> Eq for TyS<'tcx> {}
538 impl<'tcx> Hash for TyS<'tcx> {
539 fn hash<H: Hasher>(&self, s: &mut H) {
540 (self as *const TyS<'_>).hash(s)
544 impl<'tcx> TyS<'tcx> {
545 pub fn is_primitive_ty(&self) -> bool {
552 TyKind::Infer(InferTy::IntVar(_)) |
553 TyKind::Infer(InferTy::FloatVar(_)) |
554 TyKind::Infer(InferTy::FreshIntTy(_)) |
555 TyKind::Infer(InferTy::FreshFloatTy(_)) => true,
556 TyKind::Ref(_, x, _) => x.is_primitive_ty(),
561 pub fn is_suggestable(&self) -> bool {
566 TyKind::Dynamic(..) |
567 TyKind::Closure(..) |
569 TyKind::Projection(..) => false,
575 impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for ty::TyS<'gcx> {
576 fn hash_stable<W: StableHasherResult>(&self,
577 hcx: &mut StableHashingContext<'a>,
578 hasher: &mut StableHasher<W>) {
582 // The other fields just provide fast access to information that is
583 // also contained in `sty`, so no need to hash them.
586 outer_exclusive_binder: _,
589 sty.hash_stable(hcx, hasher);
593 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
595 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
596 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
598 pub type CanonicalTy<'gcx> = Canonical<'gcx, Ty<'gcx>>;
601 /// A dummy type used to force List to by unsized without requiring fat pointers
602 type OpaqueListContents;
605 /// A wrapper for slices with the additional invariant
606 /// that the slice is interned and no other slice with
607 /// the same contents can exist in the same context.
608 /// This means we can use pointer for both
609 /// equality comparisons and hashing.
610 /// Note: `Slice` was already taken by the `Ty`.
615 opaque: OpaqueListContents,
618 unsafe impl<T: Sync> Sync for List<T> {}
620 impl<T: Copy> List<T> {
622 fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx List<T> {
623 assert!(!mem::needs_drop::<T>());
624 assert!(mem::size_of::<T>() != 0);
625 assert!(slice.len() != 0);
627 // Align up the size of the len (usize) field
628 let align = mem::align_of::<T>();
629 let align_mask = align - 1;
630 let offset = mem::size_of::<usize>();
631 let offset = (offset + align_mask) & !align_mask;
633 let size = offset + slice.len() * mem::size_of::<T>();
635 let mem = arena.alloc_raw(
637 cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
639 let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
641 result.len = slice.len();
643 // Write the elements
644 let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
645 arena_slice.copy_from_slice(slice);
652 impl<T: fmt::Debug> fmt::Debug for List<T> {
653 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
658 impl<T: Encodable> Encodable for List<T> {
660 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
665 impl<T> Ord for List<T> where T: Ord {
666 fn cmp(&self, other: &List<T>) -> Ordering {
667 if self == other { Ordering::Equal } else {
668 <[T] as Ord>::cmp(&**self, &**other)
673 impl<T> PartialOrd for List<T> where T: PartialOrd {
674 fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> {
675 if self == other { Some(Ordering::Equal) } else {
676 <[T] as PartialOrd>::partial_cmp(&**self, &**other)
681 impl<T: PartialEq> PartialEq for List<T> {
683 fn eq(&self, other: &List<T>) -> bool {
687 impl<T: Eq> Eq for List<T> {}
689 impl<T> Hash for List<T> {
691 fn hash<H: Hasher>(&self, s: &mut H) {
692 (self as *const List<T>).hash(s)
696 impl<T> Deref for List<T> {
699 fn deref(&self) -> &[T] {
701 slice::from_raw_parts(self.data.as_ptr(), self.len)
706 impl<'a, T> IntoIterator for &'a List<T> {
708 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
710 fn into_iter(self) -> Self::IntoIter {
715 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
719 pub fn empty<'a>() -> &'a List<T> {
720 #[repr(align(64), C)]
721 struct EmptySlice([u8; 64]);
722 static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
723 assert!(mem::align_of::<T>() <= 64);
725 &*(&EMPTY_SLICE as *const _ as *const List<T>)
730 /// Upvars do not get their own node-id. Instead, we use the pair of
731 /// the original var id (that is, the root variable that is referenced
732 /// by the upvar) and the id of the closure expression.
733 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
735 pub var_id: hir::HirId,
736 pub closure_expr_id: LocalDefId,
739 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
740 pub enum BorrowKind {
741 /// Data must be immutable and is aliasable.
744 /// Data must be immutable but not aliasable. This kind of borrow
745 /// cannot currently be expressed by the user and is used only in
746 /// implicit closure bindings. It is needed when the closure
747 /// is borrowing or mutating a mutable referent, e.g.:
749 /// let x: &mut isize = ...;
750 /// let y = || *x += 5;
752 /// If we were to try to translate this closure into a more explicit
753 /// form, we'd encounter an error with the code as written:
755 /// struct Env { x: & &mut isize }
756 /// let x: &mut isize = ...;
757 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
758 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
760 /// This is then illegal because you cannot mutate a `&mut` found
761 /// in an aliasable location. To solve, you'd have to translate with
762 /// an `&mut` borrow:
764 /// struct Env { x: & &mut isize }
765 /// let x: &mut isize = ...;
766 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
767 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
769 /// Now the assignment to `**env.x` is legal, but creating a
770 /// mutable pointer to `x` is not because `x` is not mutable. We
771 /// could fix this by declaring `x` as `let mut x`. This is ok in
772 /// user code, if awkward, but extra weird for closures, since the
773 /// borrow is hidden.
775 /// So we introduce a "unique imm" borrow -- the referent is
776 /// immutable, but not aliasable. This solves the problem. For
777 /// simplicity, we don't give users the way to express this
778 /// borrow, it's just used when translating closures.
781 /// Data is mutable and not aliasable.
785 /// Information describing the capture of an upvar. This is computed
786 /// during `typeck`, specifically by `regionck`.
787 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
788 pub enum UpvarCapture<'tcx> {
789 /// Upvar is captured by value. This is always true when the
790 /// closure is labeled `move`, but can also be true in other cases
791 /// depending on inference.
794 /// Upvar is captured by reference.
795 ByRef(UpvarBorrow<'tcx>),
798 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
799 pub struct UpvarBorrow<'tcx> {
800 /// The kind of borrow: by-ref upvars have access to shared
801 /// immutable borrows, which are not part of the normal language
803 pub kind: BorrowKind,
805 /// Region of the resulting reference.
806 pub region: ty::Region<'tcx>,
809 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
811 #[derive(Copy, Clone)]
812 pub struct ClosureUpvar<'tcx> {
818 #[derive(Clone, Copy, PartialEq, Eq)]
819 pub enum IntVarValue {
821 UintType(ast::UintTy),
824 #[derive(Clone, Copy, PartialEq, Eq)]
825 pub struct FloatVarValue(pub ast::FloatTy);
827 impl ty::EarlyBoundRegion {
828 pub fn to_bound_region(&self) -> ty::BoundRegion {
829 ty::BoundRegion::BrNamed(self.def_id, self.name)
832 /// Does this early bound region have a name? Early bound regions normally
833 /// always have names except when using anonymous lifetimes (`'_`).
834 pub fn has_name(&self) -> bool {
835 self.name != keywords::UnderscoreLifetime.name().as_interned_str()
839 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
840 pub enum GenericParamDefKind {
844 object_lifetime_default: ObjectLifetimeDefault,
845 synthetic: Option<hir::SyntheticTyParamKind>,
849 #[derive(Clone, RustcEncodable, RustcDecodable)]
850 pub struct GenericParamDef {
851 pub name: InternedString,
855 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
856 /// on generic parameter `'a`/`T`, asserts data behind the parameter
857 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
858 pub pure_wrt_drop: bool,
860 pub kind: GenericParamDefKind,
863 impl GenericParamDef {
864 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
866 GenericParamDefKind::Lifetime => {
867 ty::EarlyBoundRegion {
873 _ => bug!("cannot convert a non-lifetime parameter def to an early bound region")
877 pub fn to_bound_region(&self) -> ty::BoundRegion {
879 GenericParamDefKind::Lifetime => {
880 self.to_early_bound_region_data().to_bound_region()
882 _ => bug!("cannot convert a non-lifetime parameter def to an early bound region")
888 pub struct GenericParamCount {
889 pub lifetimes: usize,
893 /// Information about the formal type/lifetime parameters associated
894 /// with an item or method. Analogous to hir::Generics.
896 /// The ordering of parameters is the same as in Subst (excluding child generics):
897 /// Self (optionally), Lifetime params..., Type params...
898 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
899 pub struct Generics {
900 pub parent: Option<DefId>,
901 pub parent_count: usize,
902 pub params: Vec<GenericParamDef>,
904 /// Reverse map to the `index` field of each `GenericParamDef`
905 pub param_def_id_to_index: FxHashMap<DefId, u32>,
908 pub has_late_bound_regions: Option<Span>,
911 impl<'a, 'gcx, 'tcx> Generics {
912 pub fn count(&self) -> usize {
913 self.parent_count + self.params.len()
916 pub fn own_counts(&self) -> GenericParamCount {
917 // We could cache this as a property of `GenericParamCount`, but
918 // the aim is to refactor this away entirely eventually and the
919 // presence of this method will be a constant reminder.
920 let mut own_counts: GenericParamCount = Default::default();
922 for param in &self.params {
924 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
925 GenericParamDefKind::Type { .. } => own_counts.types += 1,
932 pub fn requires_monomorphization(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
933 for param in &self.params {
935 GenericParamDefKind::Type { .. } => return true,
936 GenericParamDefKind::Lifetime => {}
939 if let Some(parent_def_id) = self.parent {
940 let parent = tcx.generics_of(parent_def_id);
941 parent.requires_monomorphization(tcx)
947 pub fn region_param(&'tcx self,
948 param: &EarlyBoundRegion,
949 tcx: TyCtxt<'a, 'gcx, 'tcx>)
950 -> &'tcx GenericParamDef
952 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
953 let param = &self.params[index as usize];
955 ty::GenericParamDefKind::Lifetime => param,
956 _ => bug!("expected lifetime parameter, but found another generic parameter")
959 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
960 .region_param(param, tcx)
964 /// Returns the `GenericParamDef` associated with this `ParamTy`.
965 pub fn type_param(&'tcx self,
967 tcx: TyCtxt<'a, 'gcx, 'tcx>)
968 -> &'tcx GenericParamDef {
969 if let Some(index) = param.idx.checked_sub(self.parent_count as u32) {
970 let param = &self.params[index as usize];
972 ty::GenericParamDefKind::Type {..} => param,
973 _ => bug!("expected type parameter, but found another generic parameter")
976 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
977 .type_param(param, tcx)
982 /// Bounds on generics.
983 #[derive(Clone, Default)]
984 pub struct GenericPredicates<'tcx> {
985 pub parent: Option<DefId>,
986 pub predicates: Vec<(Predicate<'tcx>, Span)>,
989 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
990 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
992 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
993 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
994 -> InstantiatedPredicates<'tcx> {
995 let mut instantiated = InstantiatedPredicates::empty();
996 self.instantiate_into(tcx, &mut instantiated, substs);
999 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
1000 -> InstantiatedPredicates<'tcx> {
1001 InstantiatedPredicates {
1002 predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
1006 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1007 instantiated: &mut InstantiatedPredicates<'tcx>,
1008 substs: &Substs<'tcx>) {
1009 if let Some(def_id) = self.parent {
1010 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
1012 instantiated.predicates.extend(
1013 self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)),
1017 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1018 -> InstantiatedPredicates<'tcx> {
1019 let mut instantiated = InstantiatedPredicates::empty();
1020 self.instantiate_identity_into(tcx, &mut instantiated);
1024 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1025 instantiated: &mut InstantiatedPredicates<'tcx>) {
1026 if let Some(def_id) = self.parent {
1027 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
1029 instantiated.predicates.extend(self.predicates.iter().map(|&(p, _)| p))
1032 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1033 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
1034 -> InstantiatedPredicates<'tcx>
1036 assert_eq!(self.parent, None);
1037 InstantiatedPredicates {
1038 predicates: self.predicates.iter().map(|(pred, _)| {
1039 pred.subst_supertrait(tcx, poly_trait_ref)
1045 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1046 pub enum Predicate<'tcx> {
1047 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
1048 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1049 /// would be the type parameters.
1050 Trait(PolyTraitPredicate<'tcx>),
1053 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1056 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1058 /// where <T as TraitRef>::Name == X, approximately.
1059 /// See `ProjectionPredicate` struct for details.
1060 Projection(PolyProjectionPredicate<'tcx>),
1063 WellFormed(Ty<'tcx>),
1065 /// trait must be object-safe
1068 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
1069 /// for some substitutions `...` and T being a closure type.
1070 /// Satisfied (or refuted) once we know the closure's kind.
1071 ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
1074 Subtype(PolySubtypePredicate<'tcx>),
1076 /// Constant initializer must evaluate successfully.
1077 ConstEvaluatable(DefId, &'tcx Substs<'tcx>),
1080 /// The crate outlives map is computed during typeck and contains the
1081 /// outlives of every item in the local crate. You should not use it
1082 /// directly, because to do so will make your pass dependent on the
1083 /// HIR of every item in the local crate. Instead, use
1084 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1086 pub struct CratePredicatesMap<'tcx> {
1087 /// For each struct with outlive bounds, maps to a vector of the
1088 /// predicate of its outlive bounds. If an item has no outlives
1089 /// bounds, it will have no entry.
1090 pub predicates: FxHashMap<DefId, Lrc<Vec<ty::Predicate<'tcx>>>>,
1092 /// An empty vector, useful for cloning.
1093 pub empty_predicate: Lrc<Vec<ty::Predicate<'tcx>>>,
1096 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1097 fn as_ref(&self) -> &Predicate<'tcx> {
1102 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
1103 /// Performs a substitution suitable for going from a
1104 /// poly-trait-ref to supertraits that must hold if that
1105 /// poly-trait-ref holds. This is slightly different from a normal
1106 /// substitution in terms of what happens with bound regions. See
1107 /// lengthy comment below for details.
1108 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1109 trait_ref: &ty::PolyTraitRef<'tcx>)
1110 -> ty::Predicate<'tcx>
1112 // The interaction between HRTB and supertraits is not entirely
1113 // obvious. Let me walk you (and myself) through an example.
1115 // Let's start with an easy case. Consider two traits:
1117 // trait Foo<'a> : Bar<'a,'a> { }
1118 // trait Bar<'b,'c> { }
1120 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
1121 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
1122 // knew that `Foo<'x>` (for any 'x) then we also know that
1123 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1124 // normal substitution.
1126 // In terms of why this is sound, the idea is that whenever there
1127 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1128 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1129 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1132 // Another example to be careful of is this:
1134 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
1135 // trait Bar1<'b,'c> { }
1137 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
1138 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
1139 // reason is similar to the previous example: any impl of
1140 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
1141 // basically we would want to collapse the bound lifetimes from
1142 // the input (`trait_ref`) and the supertraits.
1144 // To achieve this in practice is fairly straightforward. Let's
1145 // consider the more complicated scenario:
1147 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
1148 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
1149 // where both `'x` and `'b` would have a DB index of 1.
1150 // The substitution from the input trait-ref is therefore going to be
1151 // `'a => 'x` (where `'x` has a DB index of 1).
1152 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1153 // early-bound parameter and `'b' is a late-bound parameter with a
1155 // - If we replace `'a` with `'x` from the input, it too will have
1156 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1157 // just as we wanted.
1159 // There is only one catch. If we just apply the substitution `'a
1160 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1161 // adjust the DB index because we substituting into a binder (it
1162 // tries to be so smart...) resulting in `for<'x> for<'b>
1163 // Bar1<'x,'b>` (we have no syntax for this, so use your
1164 // imagination). Basically the 'x will have DB index of 2 and 'b
1165 // will have DB index of 1. Not quite what we want. So we apply
1166 // the substitution to the *contents* of the trait reference,
1167 // rather than the trait reference itself (put another way, the
1168 // substitution code expects equal binding levels in the values
1169 // from the substitution and the value being substituted into, and
1170 // this trick achieves that).
1172 let substs = &trait_ref.skip_binder().substs;
1174 Predicate::Trait(ref binder) =>
1175 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1176 Predicate::Subtype(ref binder) =>
1177 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1178 Predicate::RegionOutlives(ref binder) =>
1179 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1180 Predicate::TypeOutlives(ref binder) =>
1181 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1182 Predicate::Projection(ref binder) =>
1183 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1184 Predicate::WellFormed(data) =>
1185 Predicate::WellFormed(data.subst(tcx, substs)),
1186 Predicate::ObjectSafe(trait_def_id) =>
1187 Predicate::ObjectSafe(trait_def_id),
1188 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1189 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1190 Predicate::ConstEvaluatable(def_id, const_substs) =>
1191 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1196 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1197 pub struct TraitPredicate<'tcx> {
1198 pub trait_ref: TraitRef<'tcx>
1200 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1202 impl<'tcx> TraitPredicate<'tcx> {
1203 pub fn def_id(&self) -> DefId {
1204 self.trait_ref.def_id
1207 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
1208 self.trait_ref.input_types()
1211 pub fn self_ty(&self) -> Ty<'tcx> {
1212 self.trait_ref.self_ty()
1216 impl<'tcx> PolyTraitPredicate<'tcx> {
1217 pub fn def_id(&self) -> DefId {
1218 // ok to skip binder since trait def-id does not care about regions
1219 self.skip_binder().def_id()
1223 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
1224 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
1225 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1226 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>,
1228 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>,
1230 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1231 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1233 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1234 pub struct SubtypePredicate<'tcx> {
1235 pub a_is_expected: bool,
1239 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1241 /// This kind of predicate has no *direct* correspondent in the
1242 /// syntax, but it roughly corresponds to the syntactic forms:
1244 /// 1. `T : TraitRef<..., Item=Type>`
1245 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1247 /// In particular, form #1 is "desugared" to the combination of a
1248 /// normal trait predicate (`T : TraitRef<...>`) and one of these
1249 /// predicates. Form #2 is a broader form in that it also permits
1250 /// equality between arbitrary types. Processing an instance of
1251 /// Form #2 eventually yields one of these `ProjectionPredicate`
1252 /// instances to normalize the LHS.
1253 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1254 pub struct ProjectionPredicate<'tcx> {
1255 pub projection_ty: ProjectionTy<'tcx>,
1259 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1261 impl<'tcx> PolyProjectionPredicate<'tcx> {
1262 /// Returns the def-id of the associated item being projected.
1263 pub fn item_def_id(&self) -> DefId {
1264 self.skip_binder().projection_ty.item_def_id
1267 pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'_, '_, '_>) -> PolyTraitRef<'tcx> {
1268 // Note: unlike with TraitRef::to_poly_trait_ref(),
1269 // self.0.trait_ref is permitted to have escaping regions.
1270 // This is because here `self` has a `Binder` and so does our
1271 // return value, so we are preserving the number of binding
1273 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1276 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1277 self.map_bound(|predicate| predicate.ty)
1280 /// The DefId of the TraitItem for the associated type.
1282 /// Note that this is not the DefId of the TraitRef containing this
1283 /// associated type, which is in tcx.associated_item(projection_def_id()).container.
1284 pub fn projection_def_id(&self) -> DefId {
1285 // ok to skip binder since trait def-id does not care about regions
1286 self.skip_binder().projection_ty.item_def_id
1290 pub trait ToPolyTraitRef<'tcx> {
1291 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1294 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1295 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1296 ty::Binder::dummy(self.clone())
1300 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1301 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1302 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1306 pub trait ToPredicate<'tcx> {
1307 fn to_predicate(&self) -> Predicate<'tcx>;
1310 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1311 fn to_predicate(&self) -> Predicate<'tcx> {
1312 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1313 trait_ref: self.clone()
1318 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1319 fn to_predicate(&self) -> Predicate<'tcx> {
1320 ty::Predicate::Trait(self.to_poly_trait_predicate())
1324 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1325 fn to_predicate(&self) -> Predicate<'tcx> {
1326 Predicate::RegionOutlives(self.clone())
1330 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1331 fn to_predicate(&self) -> Predicate<'tcx> {
1332 Predicate::TypeOutlives(self.clone())
1336 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1337 fn to_predicate(&self) -> Predicate<'tcx> {
1338 Predicate::Projection(self.clone())
1342 impl<'tcx> Predicate<'tcx> {
1343 /// Iterates over the types in this predicate. Note that in all
1344 /// cases this is skipping over a binder, so late-bound regions
1345 /// with depth 0 are bound by the predicate.
1346 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1347 let vec: Vec<_> = match *self {
1348 ty::Predicate::Trait(ref data) => {
1349 data.skip_binder().input_types().collect()
1351 ty::Predicate::Subtype(binder) => {
1352 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1355 ty::Predicate::TypeOutlives(binder) => {
1356 vec![binder.skip_binder().0]
1358 ty::Predicate::RegionOutlives(..) => {
1361 ty::Predicate::Projection(ref data) => {
1362 let inner = data.skip_binder();
1363 inner.projection_ty.substs.types().chain(Some(inner.ty)).collect()
1365 ty::Predicate::WellFormed(data) => {
1368 ty::Predicate::ObjectSafe(_trait_def_id) => {
1371 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1372 closure_substs.substs.types().collect()
1374 ty::Predicate::ConstEvaluatable(_, substs) => {
1375 substs.types().collect()
1379 // The only reason to collect into a vector here is that I was
1380 // too lazy to make the full (somewhat complicated) iterator
1381 // type that would be needed here. But I wanted this fn to
1382 // return an iterator conceptually, rather than a `Vec`, so as
1383 // to be closer to `Ty::walk`.
1387 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1389 Predicate::Trait(ref t) => {
1390 Some(t.to_poly_trait_ref())
1392 Predicate::Projection(..) |
1393 Predicate::Subtype(..) |
1394 Predicate::RegionOutlives(..) |
1395 Predicate::WellFormed(..) |
1396 Predicate::ObjectSafe(..) |
1397 Predicate::ClosureKind(..) |
1398 Predicate::TypeOutlives(..) |
1399 Predicate::ConstEvaluatable(..) => {
1405 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1407 Predicate::TypeOutlives(data) => {
1410 Predicate::Trait(..) |
1411 Predicate::Projection(..) |
1412 Predicate::Subtype(..) |
1413 Predicate::RegionOutlives(..) |
1414 Predicate::WellFormed(..) |
1415 Predicate::ObjectSafe(..) |
1416 Predicate::ClosureKind(..) |
1417 Predicate::ConstEvaluatable(..) => {
1424 /// Represents the bounds declared on a particular set of type
1425 /// parameters. Should eventually be generalized into a flag list of
1426 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1427 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1428 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1429 /// the `GenericPredicates` are expressed in terms of the bound type
1430 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1431 /// represented a set of bounds for some particular instantiation,
1432 /// meaning that the generic parameters have been substituted with
1437 /// struct Foo<T,U:Bar<T>> { ... }
1439 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1440 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1441 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1442 /// [usize:Bar<isize>]]`.
1444 pub struct InstantiatedPredicates<'tcx> {
1445 pub predicates: Vec<Predicate<'tcx>>,
1448 impl<'tcx> InstantiatedPredicates<'tcx> {
1449 pub fn empty() -> InstantiatedPredicates<'tcx> {
1450 InstantiatedPredicates { predicates: vec![] }
1453 pub fn is_empty(&self) -> bool {
1454 self.predicates.is_empty()
1458 /// "Universes" are used during type- and trait-checking in the
1459 /// presence of `for<..>` binders to control what sets of names are
1460 /// visible. Universes are arranged into a tree: the root universe
1461 /// contains names that are always visible. But when you enter into
1462 /// some subuniverse, then it may add names that are only visible
1463 /// within that subtree (but it can still name the names of its
1464 /// ancestor universes).
1466 /// To make this more concrete, consider this program:
1470 /// fn bar<T>(x: T) {
1471 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1475 /// The struct name `Foo` is in the root universe U0. But the type
1476 /// parameter `T`, introduced on `bar`, is in a subuniverse U1 --
1477 /// i.e., within `bar`, we can name both `T` and `Foo`, but outside of
1478 /// `bar`, we cannot name `T`. Then, within the type of `y`, the
1479 /// region `'a` is in a subuniverse U2 of U1, because we can name it
1480 /// inside the fn type but not outside.
1482 /// Universes are used to do type- and trait-checking around these
1483 /// "forall" binders (also called **universal quantification**). The
1484 /// idea is that when, in the body of `bar`, we refer to `T` as a
1485 /// type, we aren't referring to any type in particular, but rather a
1486 /// kind of "fresh" type that is distinct from all other types we have
1487 /// actually declared. This is called a **placeholder** type, and we
1488 /// use universes to talk about this. In other words, a type name in
1489 /// universe 0 always corresponds to some "ground" type that the user
1490 /// declared, but a type name in a non-zero universe is a placeholder
1491 /// type -- an idealized representative of "types in general" that we
1492 /// use for checking generic functions.
1493 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
1494 pub struct UniverseIndex(u32);
1496 impl UniverseIndex {
1497 /// The root universe, where things that the user defined are
1499 pub const ROOT: Self = UniverseIndex(0);
1501 /// The "max universe" -- this isn't really a valid universe, but
1502 /// it's useful sometimes as a "starting value" when you are
1503 /// taking the minimum of a (non-empty!) set of universes.
1504 pub const MAX: Self = UniverseIndex(::std::u32::MAX);
1506 /// Creates a universe index from the given integer. Not to be
1507 /// used lightly lest you pick a bad value. But sometimes we
1508 /// convert universe indices into integers and back for various
1510 pub fn from_u32(index: u32) -> Self {
1511 UniverseIndex(index)
1514 /// A "subuniverse" corresponds to being inside a `forall` quantifier.
1515 /// So, for example, suppose we have this type in universe `U`:
1518 /// for<'a> fn(&'a u32)
1521 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1522 /// subuniverse of `U` -- in this new universe, we can name the
1523 /// region `'a`, but that region was not nameable from `U` because
1524 /// it was not in scope there.
1525 pub fn subuniverse(self) -> UniverseIndex {
1526 UniverseIndex(self.0.checked_add(1).unwrap())
1529 /// True if the names in this universe are a subset of the names in `other`.
1530 pub fn is_subset_of(self, other: UniverseIndex) -> bool {
1534 pub fn as_u32(&self) -> u32 {
1538 pub fn as_usize(&self) -> usize {
1543 impl fmt::Debug for UniverseIndex {
1544 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
1545 write!(fmt, "U{}", self.as_u32())
1549 impl From<u32> for UniverseIndex {
1550 fn from(index: u32) -> Self {
1551 UniverseIndex(index)
1555 /// The "placeholder index" fully defines a placeholder region.
1556 /// Placeholder regions are identified by both a **universe** as well
1557 /// as a "bound-region" within that universe. The `bound_region` is
1558 /// basically a name -- distinct bound regions within the same
1559 /// universe are just two regions with an unknown relationship to one
1561 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
1562 pub struct Placeholder {
1563 pub universe: UniverseIndex,
1564 pub name: BoundRegion,
1567 /// When type checking, we use the `ParamEnv` to track
1568 /// details about the set of where-clauses that are in scope at this
1569 /// particular point.
1570 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1571 pub struct ParamEnv<'tcx> {
1572 /// Obligations that the caller must satisfy. This is basically
1573 /// the set of bounds on the in-scope type parameters, translated
1574 /// into Obligations, and elaborated and normalized.
1575 pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1577 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1578 /// want `Reveal::All` -- note that this is always paired with an
1579 /// empty environment. To get that, use `ParamEnv::reveal()`.
1580 pub reveal: traits::Reveal,
1583 impl<'tcx> ParamEnv<'tcx> {
1584 /// Construct a trait environment suitable for contexts where
1585 /// there are no where clauses in scope. Hidden types (like `impl
1586 /// Trait`) are left hidden, so this is suitable for ordinary
1588 pub fn empty() -> Self {
1589 Self::new(List::empty(), Reveal::UserFacing)
1592 /// Construct a trait environment with no where clauses in scope
1593 /// where the values of all `impl Trait` and other hidden types
1594 /// are revealed. This is suitable for monomorphized, post-typeck
1595 /// environments like codegen or doing optimizations.
1597 /// NB. If you want to have predicates in scope, use `ParamEnv::new`,
1598 /// or invoke `param_env.with_reveal_all()`.
1599 pub fn reveal_all() -> Self {
1600 Self::new(List::empty(), Reveal::All)
1603 /// Construct a trait environment with the given set of predicates.
1604 pub fn new(caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1607 ty::ParamEnv { caller_bounds, reveal }
1610 /// Returns a new parameter environment with the same clauses, but
1611 /// which "reveals" the true results of projections in all cases
1612 /// (even for associated types that are specializable). This is
1613 /// the desired behavior during codegen and certain other special
1614 /// contexts; normally though we want to use `Reveal::UserFacing`,
1615 /// which is the default.
1616 pub fn with_reveal_all(self) -> Self {
1617 ty::ParamEnv { reveal: Reveal::All, ..self }
1620 /// Returns this same environment but with no caller bounds.
1621 pub fn without_caller_bounds(self) -> Self {
1622 ty::ParamEnv { caller_bounds: List::empty(), ..self }
1625 /// Creates a suitable environment in which to perform trait
1626 /// queries on the given value. When type-checking, this is simply
1627 /// the pair of the environment plus value. But when reveal is set to
1628 /// All, then if `value` does not reference any type parameters, we will
1629 /// pair it with the empty environment. This improves caching and is generally
1632 /// NB: We preserve the environment when type-checking because it
1633 /// is possible for the user to have wacky where-clauses like
1634 /// `where Box<u32>: Copy`, which are clearly never
1635 /// satisfiable. We generally want to behave as if they were true,
1636 /// although the surrounding function is never reachable.
1637 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1639 Reveal::UserFacing => {
1648 || value.needs_infer()
1649 || value.has_param_types()
1650 || value.has_self_ty()
1658 param_env: self.without_caller_bounds(),
1667 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1668 pub struct ParamEnvAnd<'tcx, T> {
1669 pub param_env: ParamEnv<'tcx>,
1673 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1674 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1675 (self.param_env, self.value)
1679 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'gcx, T>
1680 where T: HashStable<StableHashingContext<'a>>
1682 fn hash_stable<W: StableHasherResult>(&self,
1683 hcx: &mut StableHashingContext<'a>,
1684 hasher: &mut StableHasher<W>) {
1690 param_env.hash_stable(hcx, hasher);
1691 value.hash_stable(hcx, hasher);
1695 #[derive(Copy, Clone, Debug)]
1696 pub struct Destructor {
1697 /// The def-id of the destructor method
1702 pub struct AdtFlags: u32 {
1703 const NO_ADT_FLAGS = 0;
1704 const IS_ENUM = 1 << 0;
1705 const IS_PHANTOM_DATA = 1 << 1;
1706 const IS_FUNDAMENTAL = 1 << 2;
1707 const IS_UNION = 1 << 3;
1708 const IS_BOX = 1 << 4;
1709 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1710 /// (i.e., this flag is never set unless this ADT is an enum).
1711 const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 5;
1716 pub struct VariantFlags: u32 {
1717 const NO_VARIANT_FLAGS = 0;
1718 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1719 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1724 pub struct VariantDef {
1725 /// The variant's DefId. If this is a tuple-like struct,
1726 /// this is the DefId of the struct's ctor.
1728 pub name: Name, // struct's name if this is a struct
1729 pub discr: VariantDiscr,
1730 pub fields: Vec<FieldDef>,
1731 pub ctor_kind: CtorKind,
1732 flags: VariantFlags,
1735 impl<'a, 'gcx, 'tcx> VariantDef {
1736 /// Create a new `VariantDef`.
1738 /// - `did` is the DefId used for the variant - for tuple-structs, it is the constructor DefId,
1739 /// and for everything else, it is the variant DefId.
1740 /// - `attribute_def_id` is the DefId that has the variant's attributes.
1741 /// this is the struct DefId for structs, and the variant DefId for variants.
1743 /// Note that we *could* use the constructor DefId, because the constructor attributes
1744 /// redirect to the base attributes, but compiling a small crate requires
1745 /// loading the AdtDefs for all the structs in the universe (e.g. coherence for any
1746 /// built-in trait), and we do not want to load attributes twice.
1748 /// If someone speeds up attribute loading to not be a performance concern, they can
1749 /// remove this hack and use the constructor DefId everywhere.
1750 pub fn new(tcx: TyCtxt<'a, 'gcx, 'tcx>,
1753 discr: VariantDiscr,
1754 fields: Vec<FieldDef>,
1756 ctor_kind: CtorKind,
1757 attribute_def_id: DefId)
1760 debug!("VariantDef::new({:?}, {:?}, {:?}, {:?}, {:?}, {:?}, {:?})", did, name, discr,
1761 fields, adt_kind, ctor_kind, attribute_def_id);
1762 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1763 if adt_kind == AdtKind::Struct && tcx.has_attr(attribute_def_id, "non_exhaustive") {
1764 debug!("found non-exhaustive field list for {:?}", did);
1765 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1778 pub fn is_field_list_non_exhaustive(&self) -> bool {
1779 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1783 impl_stable_hash_for!(struct VariantDef {
1792 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1793 pub enum VariantDiscr {
1794 /// Explicit value for this variant, i.e. `X = 123`.
1795 /// The `DefId` corresponds to the embedded constant.
1798 /// The previous variant's discriminant plus one.
1799 /// For efficiency reasons, the distance from the
1800 /// last `Explicit` discriminant is being stored,
1801 /// or `0` for the first variant, if it has none.
1806 pub struct FieldDef {
1809 pub vis: Visibility,
1812 /// The definition of an abstract data type - a struct or enum.
1814 /// These are all interned (by intern_adt_def) into the adt_defs
1818 pub variants: Vec<VariantDef>,
1820 pub repr: ReprOptions,
1823 impl PartialOrd for AdtDef {
1824 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1825 Some(self.cmp(&other))
1829 /// There should be only one AdtDef for each `did`, therefore
1830 /// it is fine to implement `Ord` only based on `did`.
1831 impl Ord for AdtDef {
1832 fn cmp(&self, other: &AdtDef) -> Ordering {
1833 self.did.cmp(&other.did)
1837 impl PartialEq for AdtDef {
1838 // AdtDef are always interned and this is part of TyS equality
1840 fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) }
1843 impl Eq for AdtDef {}
1845 impl Hash for AdtDef {
1847 fn hash<H: Hasher>(&self, s: &mut H) {
1848 (self as *const AdtDef).hash(s)
1852 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1853 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1858 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1861 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1862 fn hash_stable<W: StableHasherResult>(&self,
1863 hcx: &mut StableHashingContext<'a>,
1864 hasher: &mut StableHasher<W>) {
1866 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> =
1867 RefCell::new(FxHashMap());
1870 let hash: Fingerprint = CACHE.with(|cache| {
1871 let addr = self as *const AdtDef as usize;
1872 *cache.borrow_mut().entry(addr).or_insert_with(|| {
1880 let mut hasher = StableHasher::new();
1881 did.hash_stable(hcx, &mut hasher);
1882 variants.hash_stable(hcx, &mut hasher);
1883 flags.hash_stable(hcx, &mut hasher);
1884 repr.hash_stable(hcx, &mut hasher);
1890 hash.hash_stable(hcx, hasher);
1894 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
1895 pub enum AdtKind { Struct, Union, Enum }
1897 impl Into<DataTypeKind> for AdtKind {
1898 fn into(self) -> DataTypeKind {
1900 AdtKind::Struct => DataTypeKind::Struct,
1901 AdtKind::Union => DataTypeKind::Union,
1902 AdtKind::Enum => DataTypeKind::Enum,
1908 #[derive(RustcEncodable, RustcDecodable, Default)]
1909 pub struct ReprFlags: u8 {
1910 const IS_C = 1 << 0;
1911 const IS_SIMD = 1 << 1;
1912 const IS_TRANSPARENT = 1 << 2;
1913 // Internal only for now. If true, don't reorder fields.
1914 const IS_LINEAR = 1 << 3;
1916 // Any of these flags being set prevent field reordering optimisation.
1917 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1918 ReprFlags::IS_SIMD.bits |
1919 ReprFlags::IS_LINEAR.bits;
1923 impl_stable_hash_for!(struct ReprFlags {
1929 /// Represents the repr options provided by the user,
1930 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1931 pub struct ReprOptions {
1932 pub int: Option<attr::IntType>,
1935 pub flags: ReprFlags,
1938 impl_stable_hash_for!(struct ReprOptions {
1946 pub fn new(tcx: TyCtxt<'_, '_, '_>, did: DefId) -> ReprOptions {
1947 let mut flags = ReprFlags::empty();
1948 let mut size = None;
1949 let mut max_align = 0;
1950 let mut min_pack = 0;
1951 for attr in tcx.get_attrs(did).iter() {
1952 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1953 flags.insert(match r {
1954 attr::ReprC => ReprFlags::IS_C,
1955 attr::ReprPacked(pack) => {
1956 min_pack = if min_pack > 0 {
1957 cmp::min(pack, min_pack)
1963 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
1964 attr::ReprSimd => ReprFlags::IS_SIMD,
1965 attr::ReprInt(i) => {
1969 attr::ReprAlign(align) => {
1970 max_align = cmp::max(align, max_align);
1977 // This is here instead of layout because the choice must make it into metadata.
1978 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1979 flags.insert(ReprFlags::IS_LINEAR);
1981 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
1985 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1987 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1989 pub fn packed(&self) -> bool { self.pack > 0 }
1991 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
1993 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1995 pub fn discr_type(&self) -> attr::IntType {
1996 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
1999 /// Returns true if this `#[repr()]` should inhabit "smart enum
2000 /// layout" optimizations, such as representing `Foo<&T>` as a
2002 pub fn inhibit_enum_layout_opt(&self) -> bool {
2003 self.c() || self.int.is_some()
2006 /// Returns true if this `#[repr()]` should inhibit struct field reordering
2007 /// optimizations, such as with repr(C) or repr(packed(1)).
2008 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
2009 !(self.flags & ReprFlags::IS_UNOPTIMISABLE).is_empty() || (self.pack == 1)
2013 impl<'a, 'gcx, 'tcx> AdtDef {
2014 fn new(tcx: TyCtxt<'_, '_, '_>,
2017 variants: Vec<VariantDef>,
2018 repr: ReprOptions) -> Self {
2019 debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
2020 let mut flags = AdtFlags::NO_ADT_FLAGS;
2021 let attrs = tcx.get_attrs(did);
2022 if attr::contains_name(&attrs, "fundamental") {
2023 flags = flags | AdtFlags::IS_FUNDAMENTAL;
2025 if Some(did) == tcx.lang_items().phantom_data() {
2026 flags = flags | AdtFlags::IS_PHANTOM_DATA;
2028 if Some(did) == tcx.lang_items().owned_box() {
2029 flags = flags | AdtFlags::IS_BOX;
2031 if kind == AdtKind::Enum && tcx.has_attr(did, "non_exhaustive") {
2032 debug!("found non-exhaustive variant list for {:?}", did);
2033 flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
2036 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
2037 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
2038 AdtKind::Struct => {}
2049 pub fn is_struct(&self) -> bool {
2050 !self.is_union() && !self.is_enum()
2054 pub fn is_union(&self) -> bool {
2055 self.flags.intersects(AdtFlags::IS_UNION)
2059 pub fn is_enum(&self) -> bool {
2060 self.flags.intersects(AdtFlags::IS_ENUM)
2064 pub fn is_variant_list_non_exhaustive(&self) -> bool {
2065 self.flags.intersects(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
2068 /// Returns the kind of the ADT - Struct or Enum.
2070 pub fn adt_kind(&self) -> AdtKind {
2073 } else if self.is_union() {
2080 pub fn descr(&self) -> &'static str {
2081 match self.adt_kind() {
2082 AdtKind::Struct => "struct",
2083 AdtKind::Union => "union",
2084 AdtKind::Enum => "enum",
2088 pub fn variant_descr(&self) -> &'static str {
2089 match self.adt_kind() {
2090 AdtKind::Struct => "struct",
2091 AdtKind::Union => "union",
2092 AdtKind::Enum => "variant",
2096 /// Returns whether this type is #[fundamental] for the purposes
2097 /// of coherence checking.
2099 pub fn is_fundamental(&self) -> bool {
2100 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
2103 /// Returns true if this is PhantomData<T>.
2105 pub fn is_phantom_data(&self) -> bool {
2106 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
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",
2200 err.report_as_error(
2201 tcx.at(tcx.def_span(expr_did)),
2202 "could not evaluate enum discriminant",
2204 if !expr_did.is_local() {
2205 span_bug!(tcx.def_span(expr_did),
2206 "variant discriminant evaluation succeeded \
2207 in its crate but failed locally");
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) {
2378 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2382 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2387 impl<'a, 'gcx, 'tcx> FieldDef {
2388 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
2389 tcx.type_of(self.did).subst(tcx, subst)
2393 /// Represents the various closure traits in the Rust language. This
2394 /// will determine the type of the environment (`self`, in the
2395 /// desuaring) argument that the closure expects.
2397 /// You can get the environment type of a closure using
2398 /// `tcx.closure_env_ty()`.
2399 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
2400 pub enum ClosureKind {
2401 // Warning: Ordering is significant here! The ordering is chosen
2402 // because the trait Fn is a subtrait of FnMut and so in turn, and
2403 // hence we order it so that Fn < FnMut < FnOnce.
2409 impl<'a, 'tcx> ClosureKind {
2410 // This is the initial value used when doing upvar inference.
2411 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2413 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
2415 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
2416 ClosureKind::FnMut => {
2417 tcx.require_lang_item(FnMutTraitLangItem)
2419 ClosureKind::FnOnce => {
2420 tcx.require_lang_item(FnOnceTraitLangItem)
2425 /// True if this a type that impls this closure kind
2426 /// must also implement `other`.
2427 pub fn extends(self, other: ty::ClosureKind) -> bool {
2428 match (self, other) {
2429 (ClosureKind::Fn, ClosureKind::Fn) => true,
2430 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2431 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2432 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2433 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2434 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2439 /// Returns the representative scalar type for this closure kind.
2440 /// See `TyS::to_opt_closure_kind` for more details.
2441 pub fn to_ty(self, tcx: TyCtxt<'_, '_, 'tcx>) -> Ty<'tcx> {
2443 ty::ClosureKind::Fn => tcx.types.i8,
2444 ty::ClosureKind::FnMut => tcx.types.i16,
2445 ty::ClosureKind::FnOnce => tcx.types.i32,
2450 impl<'tcx> TyS<'tcx> {
2451 /// Iterator that walks `self` and any types reachable from
2452 /// `self`, in depth-first order. Note that just walks the types
2453 /// that appear in `self`, it does not descend into the fields of
2454 /// structs or variants. For example:
2457 /// isize => { isize }
2458 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2459 /// [isize] => { [isize], isize }
2461 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2462 TypeWalker::new(self)
2465 /// Iterator that walks the immediate children of `self`. Hence
2466 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2467 /// (but not `i32`, like `walk`).
2468 pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
2469 walk::walk_shallow(self)
2472 /// Walks `ty` and any types appearing within `ty`, invoking the
2473 /// callback `f` on each type. If the callback returns false, then the
2474 /// children of the current type are ignored.
2476 /// Note: prefer `ty.walk()` where possible.
2477 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2478 where F : FnMut(Ty<'tcx>) -> bool
2480 let mut walker = self.walk();
2481 while let Some(ty) = walker.next() {
2483 walker.skip_current_subtree();
2490 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2492 hir::MutMutable => MutBorrow,
2493 hir::MutImmutable => ImmBorrow,
2497 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2498 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2499 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2501 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2503 MutBorrow => hir::MutMutable,
2504 ImmBorrow => hir::MutImmutable,
2506 // We have no type corresponding to a unique imm borrow, so
2507 // use `&mut`. It gives all the capabilities of an `&uniq`
2508 // and hence is a safe "over approximation".
2509 UniqueImmBorrow => hir::MutMutable,
2513 pub fn to_user_str(&self) -> &'static str {
2515 MutBorrow => "mutable",
2516 ImmBorrow => "immutable",
2517 UniqueImmBorrow => "uniquely immutable",
2522 #[derive(Debug, Clone)]
2523 pub enum Attributes<'gcx> {
2524 Owned(Lrc<[ast::Attribute]>),
2525 Borrowed(&'gcx [ast::Attribute])
2528 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2529 type Target = [ast::Attribute];
2531 fn deref(&self) -> &[ast::Attribute] {
2533 &Attributes::Owned(ref data) => &data,
2534 &Attributes::Borrowed(data) => data
2539 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2540 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2541 self.typeck_tables_of(self.hir.body_owner_def_id(body))
2544 /// Returns an iterator of the def-ids for all body-owners in this
2545 /// crate. If you would prefer to iterate over the bodies
2546 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
2549 ) -> impl Iterator<Item = DefId> + Captures<'tcx> + Captures<'gcx> + 'a {
2553 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
2556 pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
2557 par_iter(&self.hir.krate().body_ids).for_each(|&body_id| {
2558 f(self.hir.body_owner_def_id(body_id))
2562 pub fn expr_span(self, id: NodeId) -> Span {
2563 match self.hir.find(id) {
2564 Some(Node::Expr(e)) => {
2568 bug!("Node id {} is not an expr: {:?}", id, f);
2571 bug!("Node id {} is not present in the node map", id);
2576 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2577 self.associated_items(id)
2578 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2582 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2583 self.associated_items(did).any(|item| {
2584 item.relevant_for_never()
2588 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2589 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2590 match self.hir.get(node_id) {
2591 Node::TraitItem(_) | Node::ImplItem(_) => true,
2595 match self.describe_def(def_id).expect("no def for def-id") {
2596 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2601 if is_associated_item {
2602 Some(self.associated_item(def_id))
2608 fn associated_item_from_trait_item_ref(self,
2609 parent_def_id: DefId,
2610 parent_vis: &hir::Visibility,
2611 trait_item_ref: &hir::TraitItemRef)
2613 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2614 let (kind, has_self) = match trait_item_ref.kind {
2615 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2616 hir::AssociatedItemKind::Method { has_self } => {
2617 (ty::AssociatedKind::Method, has_self)
2619 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2620 hir::AssociatedItemKind::Existential => bug!("only impls can have existentials"),
2624 ident: trait_item_ref.ident,
2626 // Visibility of trait items is inherited from their traits.
2627 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2628 defaultness: trait_item_ref.defaultness,
2630 container: TraitContainer(parent_def_id),
2631 method_has_self_argument: has_self
2635 fn associated_item_from_impl_item_ref(self,
2636 parent_def_id: DefId,
2637 impl_item_ref: &hir::ImplItemRef)
2639 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2640 let (kind, has_self) = match impl_item_ref.kind {
2641 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2642 hir::AssociatedItemKind::Method { has_self } => {
2643 (ty::AssociatedKind::Method, has_self)
2645 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2646 hir::AssociatedItemKind::Existential => (ty::AssociatedKind::Existential, false),
2650 ident: impl_item_ref.ident,
2652 // Visibility of trait impl items doesn't matter.
2653 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2654 defaultness: impl_item_ref.defaultness,
2656 container: ImplContainer(parent_def_id),
2657 method_has_self_argument: has_self
2661 pub fn field_index(self, node_id: NodeId, tables: &TypeckTables<'_>) -> usize {
2662 let hir_id = self.hir.node_to_hir_id(node_id);
2663 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2666 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2667 variant.fields.iter().position(|field| {
2668 self.adjust_ident(ident, variant.did, DUMMY_NODE_ID).0 == field.ident.modern()
2672 pub fn associated_items(
2675 ) -> impl Iterator<Item = AssociatedItem> + 'a {
2676 let def_ids = self.associated_item_def_ids(def_id);
2677 Box::new((0..def_ids.len()).map(move |i| self.associated_item(def_ids[i])))
2678 as Box<dyn Iterator<Item = AssociatedItem> + 'a>
2681 /// Returns true if the impls are the same polarity and the trait either
2682 /// has no items or is annotated #[marker] and prevents item overrides.
2683 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2684 if self.features().overlapping_marker_traits {
2685 let trait1_is_empty = self.impl_trait_ref(def_id1)
2686 .map_or(false, |trait_ref| {
2687 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2689 let trait2_is_empty = self.impl_trait_ref(def_id2)
2690 .map_or(false, |trait_ref| {
2691 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2693 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2696 } else if self.features().marker_trait_attr {
2697 let is_marker_impl = |def_id: DefId| -> bool {
2698 let trait_ref = self.impl_trait_ref(def_id);
2699 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2701 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2702 && is_marker_impl(def_id1)
2703 && is_marker_impl(def_id2)
2709 // Returns `ty::VariantDef` if `def` refers to a struct,
2710 // or variant or their constructors, panics otherwise.
2711 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2713 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2714 let enum_did = self.parent_def_id(did).unwrap();
2715 self.adt_def(enum_did).variant_with_id(did)
2717 Def::Struct(did) | Def::Union(did) => {
2718 self.adt_def(did).non_enum_variant()
2720 Def::StructCtor(ctor_did, ..) => {
2721 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2722 self.adt_def(did).non_enum_variant()
2724 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2728 /// Given a `VariantDef`, returns the def-id of the `AdtDef` of which it is a part.
2729 pub fn adt_def_id_of_variant(self, variant_def: &'tcx VariantDef) -> DefId {
2730 let def_key = self.def_key(variant_def.did);
2731 match def_key.disambiguated_data.data {
2732 // for enum variants and tuple structs, the def-id of the ADT itself
2733 // is the *parent* of the variant
2734 DefPathData::EnumVariant(..) | DefPathData::StructCtor =>
2735 DefId { krate: variant_def.did.krate, index: def_key.parent.unwrap() },
2737 // otherwise, for structs and unions, they share a def-id
2738 _ => variant_def.did,
2742 pub fn item_name(self, id: DefId) -> InternedString {
2743 if id.index == CRATE_DEF_INDEX {
2744 self.original_crate_name(id.krate).as_interned_str()
2746 let def_key = self.def_key(id);
2747 // The name of a StructCtor is that of its struct parent.
2748 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2749 self.item_name(DefId {
2751 index: def_key.parent.unwrap()
2754 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2755 bug!("item_name: no name for {:?}", self.def_path(id));
2761 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2762 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2766 ty::InstanceDef::Item(did) => {
2767 self.optimized_mir(did)
2769 ty::InstanceDef::Intrinsic(..) |
2770 ty::InstanceDef::FnPtrShim(..) |
2771 ty::InstanceDef::Virtual(..) |
2772 ty::InstanceDef::ClosureOnceShim { .. } |
2773 ty::InstanceDef::DropGlue(..) |
2774 ty::InstanceDef::CloneShim(..) => {
2775 self.mir_shims(instance)
2780 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2781 /// Returns None if there is no MIR for the DefId
2782 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2783 if self.is_mir_available(did) {
2784 Some(self.optimized_mir(did))
2790 /// Get the attributes of a definition.
2791 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2792 if let Some(id) = self.hir.as_local_node_id(did) {
2793 Attributes::Borrowed(self.hir.attrs(id))
2795 Attributes::Owned(self.item_attrs(did))
2799 /// Determine whether an item is annotated with an attribute
2800 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2801 attr::contains_name(&self.get_attrs(did), attr)
2804 /// Returns true if this is an `auto trait`.
2805 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
2806 self.trait_def(trait_def_id).has_auto_impl
2809 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
2810 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
2813 /// Given the def_id of an impl, return the def_id of the trait it implements.
2814 /// If it implements no trait, return `None`.
2815 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2816 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2819 /// If the given def ID describes a method belonging to an impl, return the
2820 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2821 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2822 let item = if def_id.krate != LOCAL_CRATE {
2823 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2824 Some(self.associated_item(def_id))
2829 self.opt_associated_item(def_id)
2832 item.and_then(|trait_item|
2833 match trait_item.container {
2834 TraitContainer(_) => None,
2835 ImplContainer(def_id) => Some(def_id),
2840 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2841 /// with the name of the crate containing the impl.
2842 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2843 if impl_did.is_local() {
2844 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2845 Ok(self.hir.span(node_id))
2847 Err(self.crate_name(impl_did.krate))
2851 // Hygienically compare a use-site name (`use_name`) for a field or an associated item with its
2852 // supposed definition name (`def_name`). The method also needs `DefId` of the supposed
2853 // definition's parent/scope to perform comparison.
2854 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
2855 self.adjust_ident(use_name, def_parent_def_id, DUMMY_NODE_ID).0 == def_name.modern()
2858 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
2859 ident = ident.modern();
2860 let target_expansion = match scope.krate {
2861 LOCAL_CRATE => self.hir.definitions().expansion_that_defined(scope.index),
2864 let scope = match ident.span.adjust(target_expansion) {
2865 Some(actual_expansion) =>
2866 self.hir.definitions().parent_module_of_macro_def(actual_expansion),
2867 None if block == DUMMY_NODE_ID => DefId::local(CRATE_DEF_INDEX), // Dummy DefId
2868 None => self.hir.get_module_parent(block),
2874 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2875 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2876 F: FnOnce(&[hir::Freevar]) -> T,
2878 let def_id = self.hir.local_def_id(fid);
2879 match self.freevars(def_id) {
2886 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
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 /// See `ParamEnv` struct def'n for details.
3000 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3004 // The param_env of an impl Trait type is its defining function's param_env
3005 if let Some(parent) = is_impl_trait_defn(tcx, def_id) {
3006 return param_env(tcx, parent);
3008 // Compute the bounds on Self and the type parameters.
3010 let InstantiatedPredicates { predicates } =
3011 tcx.predicates_of(def_id).instantiate_identity(tcx);
3013 // Finally, we have to normalize the bounds in the environment, in
3014 // case they contain any associated type projections. This process
3015 // can yield errors if the put in illegal associated types, like
3016 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
3017 // report these errors right here; this doesn't actually feel
3018 // right to me, because constructing the environment feels like a
3019 // kind of a "idempotent" action, but I'm not sure where would be
3020 // a better place. In practice, we construct environments for
3021 // every fn once during type checking, and we'll abort if there
3022 // are any errors at that point, so after type checking you can be
3023 // sure that this will succeed without errors anyway.
3025 let unnormalized_env = ty::ParamEnv::new(tcx.intern_predicates(&predicates),
3026 traits::Reveal::UserFacing);
3028 let body_id = tcx.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
3029 tcx.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_id)
3031 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
3032 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
3035 fn crate_disambiguator<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3036 crate_num: CrateNum) -> CrateDisambiguator {
3037 assert_eq!(crate_num, LOCAL_CRATE);
3038 tcx.sess.local_crate_disambiguator()
3041 fn original_crate_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3042 crate_num: CrateNum) -> Symbol {
3043 assert_eq!(crate_num, LOCAL_CRATE);
3044 tcx.crate_name.clone()
3047 fn crate_hash<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3048 crate_num: CrateNum)
3050 assert_eq!(crate_num, LOCAL_CRATE);
3054 fn instance_def_size_estimate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3055 instance_def: InstanceDef<'tcx>)
3057 match instance_def {
3058 InstanceDef::Item(..) |
3059 InstanceDef::DropGlue(..) => {
3060 let mir = tcx.instance_mir(instance_def);
3061 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
3063 // Estimate the size of other compiler-generated shims to be 1.
3068 pub fn provide(providers: &mut ty::query::Providers<'_>) {
3069 context::provide(providers);
3070 erase_regions::provide(providers);
3071 layout::provide(providers);
3072 util::provide(providers);
3073 constness::provide(providers);
3074 *providers = ty::query::Providers {
3076 associated_item_def_ids,
3077 adt_sized_constraint,
3081 crate_disambiguator,
3082 original_crate_name,
3084 trait_impls_of: trait_def::trait_impls_of_provider,
3085 instance_def_size_estimate,
3090 /// A map for the local crate mapping each type to a vector of its
3091 /// inherent impls. This is not meant to be used outside of coherence;
3092 /// rather, you should request the vector for a specific type via
3093 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
3094 /// (constructing this map requires touching the entire crate).
3095 #[derive(Clone, Debug)]
3096 pub struct CrateInherentImpls {
3097 pub inherent_impls: DefIdMap<Lrc<Vec<DefId>>>,
3100 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
3101 pub struct SymbolName {
3102 // FIXME: we don't rely on interning or equality here - better have
3103 // this be a `&'tcx str`.
3104 pub name: InternedString
3107 impl_stable_hash_for!(struct self::SymbolName {
3112 pub fn new(name: &str) -> SymbolName {
3114 name: Symbol::intern(name).as_interned_str()
3118 pub fn as_str(&self) -> LocalInternedString {
3123 impl fmt::Display for SymbolName {
3124 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3125 fmt::Display::fmt(&self.name, fmt)
3129 impl fmt::Debug for SymbolName {
3130 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3131 fmt::Display::fmt(&self.name, fmt)