// ignore-tidy-filelength pub use self::fold::{TypeFoldable, TypeFolder, TypeVisitor}; pub use self::AssocItemContainer::*; pub use self::BorrowKind::*; pub use self::IntVarValue::*; pub use self::Variance::*; use crate::hir::exports::ExportMap; use crate::hir::place::Place as HirPlace; use crate::ich::StableHashingContext; use crate::middle::cstore::CrateStoreDyn; use crate::middle::resolve_lifetime::ObjectLifetimeDefault; use crate::mir::interpret::ErrorHandled; use crate::mir::Body; use crate::mir::GeneratorLayout; use crate::traits::{self, Reveal}; use crate::ty; use crate::ty::subst::{GenericArg, InternalSubsts, Subst, SubstsRef}; use crate::ty::util::{Discr, IntTypeExt}; use rustc_ast as ast; use rustc_attr as attr; use rustc_data_structures::captures::Captures; use rustc_data_structures::fingerprint::Fingerprint; use rustc_data_structures::fx::FxHashMap; use rustc_data_structures::fx::FxHashSet; use rustc_data_structures::fx::FxIndexMap; use rustc_data_structures::sorted_map::SortedIndexMultiMap; use rustc_data_structures::stable_hasher::{HashStable, StableHasher}; use rustc_data_structures::sync::{self, par_iter, ParallelIterator}; use rustc_data_structures::tagged_ptr::CopyTaggedPtr; use rustc_errors::ErrorReported; use rustc_hir as hir; use rustc_hir::def::{CtorKind, CtorOf, DefKind, Namespace, Res}; use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, CRATE_DEF_INDEX}; use rustc_hir::lang_items::LangItem; use rustc_hir::{Constness, Node}; use rustc_index::vec::{Idx, IndexVec}; use rustc_macros::HashStable; use rustc_serialize::{self, Encodable, Encoder}; use rustc_session::DataTypeKind; use rustc_span::hygiene::ExpnId; use rustc_span::symbol::{kw, sym, Ident, Symbol}; use rustc_span::Span; use rustc_target::abi::{Align, VariantIdx}; use std::cell::RefCell; use std::cmp::Ordering; use std::fmt; use std::hash::{Hash, Hasher}; use std::ops::{ControlFlow, Range}; use std::ptr; use std::str; pub use self::sty::BoundRegion::*; pub use self::sty::InferTy::*; pub use self::sty::RegionKind; pub use self::sty::RegionKind::*; pub use self::sty::TyKind::*; pub use self::sty::{Binder, BoundTy, BoundTyKind, BoundVar, DebruijnIndex, INNERMOST}; pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region}; pub use self::sty::{CanonicalPolyFnSig, FnSig, GenSig, PolyFnSig, PolyGenSig}; pub use self::sty::{ClosureSubsts, GeneratorSubsts, TypeAndMut, UpvarSubsts}; pub use self::sty::{ClosureSubstsParts, GeneratorSubstsParts}; pub use self::sty::{ConstVid, FloatVid, IntVid, RegionVid, TyVid}; pub use self::sty::{ExistentialPredicate, InferTy, ParamConst, ParamTy, ProjectionTy}; pub use self::sty::{ExistentialProjection, PolyExistentialProjection}; pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef}; pub use self::sty::{PolyTraitRef, TraitRef, TyKind}; pub use crate::ty::diagnostics::*; pub use self::binding::BindingMode; pub use self::binding::BindingMode::*; pub use self::context::{tls, FreeRegionInfo, TyCtxt}; pub use self::context::{ CanonicalUserType, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, DelaySpanBugEmitted, ResolvedOpaqueTy, UserType, UserTypeAnnotationIndex, }; pub use self::context::{ CtxtInterners, GeneratorInteriorTypeCause, GlobalCtxt, Lift, TypeckResults, }; pub use self::instance::{Instance, InstanceDef}; pub use self::list::List; pub use self::trait_def::TraitDef; pub use self::query::queries; pub use self::consts::{Const, ConstInt, ConstKind, InferConst, ScalarInt}; pub mod _match; pub mod adjustment; pub mod binding; pub mod cast; pub mod codec; mod erase_regions; pub mod error; pub mod fast_reject; pub mod flags; pub mod fold; pub mod inhabitedness; pub mod layout; pub mod normalize_erasing_regions; pub mod outlives; pub mod print; pub mod query; pub mod relate; pub mod subst; pub mod trait_def; pub mod util; pub mod walk; mod consts; mod context; mod diagnostics; mod instance; mod list; mod structural_impls; mod sty; // Data types pub struct ResolverOutputs { pub definitions: rustc_hir::definitions::Definitions, pub cstore: Box, pub visibilities: FxHashMap, pub extern_crate_map: FxHashMap, pub maybe_unused_trait_imports: FxHashSet, pub maybe_unused_extern_crates: Vec<(LocalDefId, Span)>, pub export_map: ExportMap, pub glob_map: FxHashMap>, /// Extern prelude entries. The value is `true` if the entry was introduced /// via `extern crate` item and not `--extern` option or compiler built-in. pub extern_prelude: FxHashMap, } #[derive(Clone, Copy, PartialEq, Eq, Debug, HashStable, Hash)] pub enum AssocItemContainer { TraitContainer(DefId), ImplContainer(DefId), } impl AssocItemContainer { /// Asserts that this is the `DefId` of an associated item declared /// in a trait, and returns the trait `DefId`. pub fn assert_trait(&self) -> DefId { match *self { TraitContainer(id) => id, _ => bug!("associated item has wrong container type: {:?}", self), } } pub fn id(&self) -> DefId { match *self { TraitContainer(id) => id, ImplContainer(id) => id, } } } /// The "header" of an impl is everything outside the body: a Self type, a trait /// ref (in the case of a trait impl), and a set of predicates (from the /// bounds / where-clauses). #[derive(Clone, Debug, TypeFoldable)] pub struct ImplHeader<'tcx> { pub impl_def_id: DefId, pub self_ty: Ty<'tcx>, pub trait_ref: Option>, pub predicates: Vec>, } #[derive(Copy, Clone, PartialEq, TyEncodable, TyDecodable, HashStable)] pub enum ImplPolarity { /// `impl Trait for Type` Positive, /// `impl !Trait for Type` Negative, /// `#[rustc_reservation_impl] impl Trait for Type` /// /// This is a "stability hack", not a real Rust feature. /// See #64631 for details. Reservation, } #[derive(Copy, Clone, Debug, PartialEq, HashStable, Eq, Hash)] pub struct AssocItem { pub def_id: DefId, #[stable_hasher(project(name))] pub ident: Ident, pub kind: AssocKind, pub vis: Visibility, pub defaultness: hir::Defaultness, pub container: AssocItemContainer, /// Whether this is a method with an explicit self /// as its first parameter, allowing method calls. pub fn_has_self_parameter: bool, } #[derive(Copy, Clone, PartialEq, Debug, HashStable, Eq, Hash)] pub enum AssocKind { Const, Fn, Type, } impl AssocKind { pub fn namespace(&self) -> Namespace { match *self { ty::AssocKind::Type => Namespace::TypeNS, ty::AssocKind::Const | ty::AssocKind::Fn => Namespace::ValueNS, } } pub fn as_def_kind(&self) -> DefKind { match self { AssocKind::Const => DefKind::AssocConst, AssocKind::Fn => DefKind::AssocFn, AssocKind::Type => DefKind::AssocTy, } } } impl AssocItem { pub fn signature(&self, tcx: TyCtxt<'_>) -> String { match self.kind { ty::AssocKind::Fn => { // We skip the binder here because the binder would deanonymize all // late-bound regions, and we don't want method signatures to show up // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound // regions just fine, showing `fn(&MyType)`. tcx.fn_sig(self.def_id).skip_binder().to_string() } ty::AssocKind::Type => format!("type {};", self.ident), ty::AssocKind::Const => { format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id)) } } } } /// A list of `ty::AssocItem`s in definition order that allows for efficient lookup by name. /// /// When doing lookup by name, we try to postpone hygienic comparison for as long as possible since /// it is relatively expensive. Instead, items are indexed by `Symbol` and hygienic comparison is /// done only on items with the same name. #[derive(Debug, Clone, PartialEq, HashStable)] pub struct AssociatedItems<'tcx> { items: SortedIndexMultiMap, } impl<'tcx> AssociatedItems<'tcx> { /// Constructs an `AssociatedItems` map from a series of `ty::AssocItem`s in definition order. pub fn new(items_in_def_order: impl IntoIterator) -> Self { let items = items_in_def_order.into_iter().map(|item| (item.ident.name, item)).collect(); AssociatedItems { items } } /// Returns a slice of associated items in the order they were defined. /// /// New code should avoid relying on definition order. If you need a particular associated item /// for a known trait, make that trait a lang item instead of indexing this array. pub fn in_definition_order(&self) -> impl '_ + Iterator { self.items.iter().map(|(_, v)| *v) } pub fn len(&self) -> usize { self.items.len() } /// Returns an iterator over all associated items with the given name, ignoring hygiene. pub fn filter_by_name_unhygienic( &self, name: Symbol, ) -> impl '_ + Iterator { self.items.get_by_key(&name).copied() } /// Returns an iterator over all associated items with the given name. /// /// Multiple items may have the same name if they are in different `Namespace`s. For example, /// an associated type can have the same name as a method. Use one of the `find_by_name_and_*` /// methods below if you know which item you are looking for. pub fn filter_by_name( &'a self, tcx: TyCtxt<'a>, ident: Ident, parent_def_id: DefId, ) -> impl 'a + Iterator { self.filter_by_name_unhygienic(ident.name) .filter(move |item| tcx.hygienic_eq(ident, item.ident, parent_def_id)) } /// Returns the associated item with the given name and `AssocKind`, if one exists. pub fn find_by_name_and_kind( &self, tcx: TyCtxt<'_>, ident: Ident, kind: AssocKind, parent_def_id: DefId, ) -> Option<&ty::AssocItem> { self.filter_by_name_unhygienic(ident.name) .filter(|item| item.kind == kind) .find(|item| tcx.hygienic_eq(ident, item.ident, parent_def_id)) } /// Returns the associated item with the given name in the given `Namespace`, if one exists. pub fn find_by_name_and_namespace( &self, tcx: TyCtxt<'_>, ident: Ident, ns: Namespace, parent_def_id: DefId, ) -> Option<&ty::AssocItem> { self.filter_by_name_unhygienic(ident.name) .filter(|item| item.kind.namespace() == ns) .find(|item| tcx.hygienic_eq(ident, item.ident, parent_def_id)) } } #[derive(Clone, Debug, PartialEq, Eq, Copy, Hash, TyEncodable, TyDecodable, HashStable)] pub enum Visibility { /// Visible everywhere (including in other crates). Public, /// Visible only in the given crate-local module. Restricted(DefId), /// Not visible anywhere in the local crate. This is the visibility of private external items. Invisible, } pub trait DefIdTree: Copy { fn parent(self, id: DefId) -> Option; fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool { if descendant.krate != ancestor.krate { return false; } while descendant != ancestor { match self.parent(descendant) { Some(parent) => descendant = parent, None => return false, } } true } } impl<'tcx> DefIdTree for TyCtxt<'tcx> { fn parent(self, id: DefId) -> Option { self.def_key(id).parent.map(|index| DefId { index, ..id }) } } impl Visibility { pub fn from_hir(visibility: &hir::Visibility<'_>, id: hir::HirId, tcx: TyCtxt<'_>) -> Self { match visibility.node { hir::VisibilityKind::Public => Visibility::Public, hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)), hir::VisibilityKind::Restricted { ref path, .. } => match path.res { // If there is no resolution, `resolve` will have already reported an error, so // assume that the visibility is public to avoid reporting more privacy errors. Res::Err => Visibility::Public, def => Visibility::Restricted(def.def_id()), }, hir::VisibilityKind::Inherited => { Visibility::Restricted(tcx.parent_module(id).to_def_id()) } } } /// Returns `true` if an item with this visibility is accessible from the given block. pub fn is_accessible_from(self, module: DefId, tree: T) -> bool { let restriction = match self { // Public items are visible everywhere. Visibility::Public => return true, // Private items from other crates are visible nowhere. Visibility::Invisible => return false, // Restricted items are visible in an arbitrary local module. Visibility::Restricted(other) if other.krate != module.krate => return false, Visibility::Restricted(module) => module, }; tree.is_descendant_of(module, restriction) } /// Returns `true` if this visibility is at least as accessible as the given visibility pub fn is_at_least(self, vis: Visibility, tree: T) -> bool { let vis_restriction = match vis { Visibility::Public => return self == Visibility::Public, Visibility::Invisible => return true, Visibility::Restricted(module) => module, }; self.is_accessible_from(vis_restriction, tree) } // Returns `true` if this item is visible anywhere in the local crate. pub fn is_visible_locally(self) -> bool { match self { Visibility::Public => true, Visibility::Restricted(def_id) => def_id.is_local(), Visibility::Invisible => false, } } } #[derive(Copy, Clone, PartialEq, TyDecodable, TyEncodable, HashStable)] pub enum Variance { Covariant, // T <: T iff A <: B -- e.g., function return type Invariant, // T <: T iff B == A -- e.g., type of mutable cell Contravariant, // T <: T iff B <: A -- e.g., function param type Bivariant, // T <: T -- e.g., unused type parameter } /// The crate variances map is computed during typeck and contains the /// variance of every item in the local crate. You should not use it /// directly, because to do so will make your pass dependent on the /// HIR of every item in the local crate. Instead, use /// `tcx.variances_of()` to get the variance for a *particular* /// item. #[derive(HashStable)] pub struct CrateVariancesMap<'tcx> { /// For each item with generics, maps to a vector of the variance /// of its generics. If an item has no generics, it will have no /// entry. pub variances: FxHashMap, } impl Variance { /// `a.xform(b)` combines the variance of a context with the /// variance of a type with the following meaning. If we are in a /// context with variance `a`, and we encounter a type argument in /// a position with variance `b`, then `a.xform(b)` is the new /// variance with which the argument appears. /// /// Example 1: /// /// *mut Vec /// /// Here, the "ambient" variance starts as covariant. `*mut T` is /// invariant with respect to `T`, so the variance in which the /// `Vec` appears is `Covariant.xform(Invariant)`, which /// yields `Invariant`. Now, the type `Vec` is covariant with /// respect to its type argument `T`, and hence the variance of /// the `i32` here is `Invariant.xform(Covariant)`, which results /// (again) in `Invariant`. /// /// Example 2: /// /// fn(*const Vec, *mut Vec` appears is /// `Contravariant.xform(Covariant)` or `Contravariant`. The same /// is true for its `i32` argument. In the `*mut T` case, the /// variance of `Vec` is `Contravariant.xform(Invariant)`, /// and hence the outermost type is `Invariant` with respect to /// `Vec` (and its `i32` argument). /// /// Source: Figure 1 of "Taming the Wildcards: /// Combining Definition- and Use-Site Variance" published in PLDI'11. pub fn xform(self, v: ty::Variance) -> ty::Variance { match (self, v) { // Figure 1, column 1. (ty::Covariant, ty::Covariant) => ty::Covariant, (ty::Covariant, ty::Contravariant) => ty::Contravariant, (ty::Covariant, ty::Invariant) => ty::Invariant, (ty::Covariant, ty::Bivariant) => ty::Bivariant, // Figure 1, column 2. (ty::Contravariant, ty::Covariant) => ty::Contravariant, (ty::Contravariant, ty::Contravariant) => ty::Covariant, (ty::Contravariant, ty::Invariant) => ty::Invariant, (ty::Contravariant, ty::Bivariant) => ty::Bivariant, // Figure 1, column 3. (ty::Invariant, _) => ty::Invariant, // Figure 1, column 4. (ty::Bivariant, _) => ty::Bivariant, } } } // Contains information needed to resolve types and (in the future) look up // the types of AST nodes. #[derive(Copy, Clone, PartialEq, Eq, Hash)] pub struct CReaderCacheKey { pub cnum: CrateNum, pub pos: usize, } bitflags! { /// Flags that we track on types. These flags are propagated upwards /// through the type during type construction, so that we can quickly check /// whether the type has various kinds of types in it without recursing /// over the type itself. pub struct TypeFlags: u32 { // Does this have parameters? Used to determine whether substitution is // required. /// Does this have [Param]? const HAS_TY_PARAM = 1 << 0; /// Does this have [ReEarlyBound]? const HAS_RE_PARAM = 1 << 1; /// Does this have [ConstKind::Param]? const HAS_CT_PARAM = 1 << 2; const NEEDS_SUBST = TypeFlags::HAS_TY_PARAM.bits | TypeFlags::HAS_RE_PARAM.bits | TypeFlags::HAS_CT_PARAM.bits; /// Does this have [Infer]? const HAS_TY_INFER = 1 << 3; /// Does this have [ReVar]? const HAS_RE_INFER = 1 << 4; /// Does this have [ConstKind::Infer]? const HAS_CT_INFER = 1 << 5; /// Does this have inference variables? Used to determine whether /// inference is required. const NEEDS_INFER = TypeFlags::HAS_TY_INFER.bits | TypeFlags::HAS_RE_INFER.bits | TypeFlags::HAS_CT_INFER.bits; /// Does this have [Placeholder]? const HAS_TY_PLACEHOLDER = 1 << 6; /// Does this have [RePlaceholder]? const HAS_RE_PLACEHOLDER = 1 << 7; /// Does this have [ConstKind::Placeholder]? const HAS_CT_PLACEHOLDER = 1 << 8; /// `true` if there are "names" of regions and so forth /// that are local to a particular fn/inferctxt const HAS_FREE_LOCAL_REGIONS = 1 << 9; /// `true` if there are "names" of types and regions and so forth /// that are local to a particular fn const HAS_FREE_LOCAL_NAMES = TypeFlags::HAS_TY_PARAM.bits | TypeFlags::HAS_CT_PARAM.bits | TypeFlags::HAS_TY_INFER.bits | TypeFlags::HAS_CT_INFER.bits | TypeFlags::HAS_TY_PLACEHOLDER.bits | TypeFlags::HAS_CT_PLACEHOLDER.bits | TypeFlags::HAS_FREE_LOCAL_REGIONS.bits; /// Does this have [Projection]? const HAS_TY_PROJECTION = 1 << 10; /// Does this have [Opaque]? const HAS_TY_OPAQUE = 1 << 11; /// Does this have [ConstKind::Unevaluated]? const HAS_CT_PROJECTION = 1 << 12; /// Could this type be normalized further? const HAS_PROJECTION = TypeFlags::HAS_TY_PROJECTION.bits | TypeFlags::HAS_TY_OPAQUE.bits | TypeFlags::HAS_CT_PROJECTION.bits; /// Is an error type/const reachable? const HAS_ERROR = 1 << 13; /// Does this have any region that "appears free" in the type? /// Basically anything but [ReLateBound] and [ReErased]. const HAS_FREE_REGIONS = 1 << 14; /// Does this have any [ReLateBound] regions? Used to check /// if a global bound is safe to evaluate. const HAS_RE_LATE_BOUND = 1 << 15; /// Does this have any [ReErased] regions? const HAS_RE_ERASED = 1 << 16; /// Does this value have parameters/placeholders/inference variables which could be /// replaced later, in a way that would change the results of `impl` specialization? const STILL_FURTHER_SPECIALIZABLE = 1 << 17; } } #[allow(rustc::usage_of_ty_tykind)] pub struct TyS<'tcx> { /// This field shouldn't be used directly and may be removed in the future. /// Use `TyS::kind()` instead. kind: TyKind<'tcx>, /// This field shouldn't be used directly and may be removed in the future. /// Use `TyS::flags()` instead. flags: TypeFlags, /// This is a kind of confusing thing: it stores the smallest /// binder such that /// /// (a) the binder itself captures nothing but /// (b) all the late-bound things within the type are captured /// by some sub-binder. /// /// So, for a type without any late-bound things, like `u32`, this /// will be *innermost*, because that is the innermost binder that /// captures nothing. But for a type `&'D u32`, where `'D` is a /// late-bound region with De Bruijn index `D`, this would be `D + 1` /// -- the binder itself does not capture `D`, but `D` is captured /// by an inner binder. /// /// We call this concept an "exclusive" binder `D` because all /// De Bruijn indices within the type are contained within `0..D` /// (exclusive). outer_exclusive_binder: ty::DebruijnIndex, } impl<'tcx> TyS<'tcx> { /// A constructor used only for internal testing. #[allow(rustc::usage_of_ty_tykind)] pub fn make_for_test( kind: TyKind<'tcx>, flags: TypeFlags, outer_exclusive_binder: ty::DebruijnIndex, ) -> TyS<'tcx> { TyS { kind, flags, outer_exclusive_binder } } } // `TyS` is used a lot. Make sure it doesn't unintentionally get bigger. #[cfg(target_arch = "x86_64")] static_assert_size!(TyS<'_>, 32); impl<'tcx> Ord for TyS<'tcx> { fn cmp(&self, other: &TyS<'tcx>) -> Ordering { self.kind().cmp(other.kind()) } } impl<'tcx> PartialOrd for TyS<'tcx> { fn partial_cmp(&self, other: &TyS<'tcx>) -> Option { Some(self.kind().cmp(other.kind())) } } impl<'tcx> PartialEq for TyS<'tcx> { #[inline] fn eq(&self, other: &TyS<'tcx>) -> bool { ptr::eq(self, other) } } impl<'tcx> Eq for TyS<'tcx> {} impl<'tcx> Hash for TyS<'tcx> { fn hash(&self, s: &mut H) { (self as *const TyS<'_>).hash(s) } } impl<'a, 'tcx> HashStable> for TyS<'tcx> { fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) { let ty::TyS { ref kind, // The other fields just provide fast access to information that is // also contained in `kind`, so no need to hash them. flags: _, outer_exclusive_binder: _, } = *self; kind.hash_stable(hcx, hasher); } } #[rustc_diagnostic_item = "Ty"] pub type Ty<'tcx> = &'tcx TyS<'tcx>; #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable)] pub struct UpvarPath { pub hir_id: hir::HirId, } /// Upvars do not get their own `NodeId`. Instead, we use the pair of /// the original var ID (that is, the root variable that is referenced /// by the upvar) and the ID of the closure expression. #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable)] pub struct UpvarId { pub var_path: UpvarPath, pub closure_expr_id: LocalDefId, } impl UpvarId { pub fn new(var_hir_id: hir::HirId, closure_def_id: LocalDefId) -> UpvarId { UpvarId { var_path: UpvarPath { hir_id: var_hir_id }, closure_expr_id: closure_def_id } } } #[derive(Clone, PartialEq, Debug, TyEncodable, TyDecodable, Copy, HashStable)] pub enum BorrowKind { /// Data must be immutable and is aliasable. ImmBorrow, /// Data must be immutable but not aliasable. This kind of borrow /// cannot currently be expressed by the user and is used only in /// implicit closure bindings. It is needed when the closure /// is borrowing or mutating a mutable referent, e.g.: /// /// ``` /// let x: &mut isize = ...; /// let y = || *x += 5; /// ``` /// /// If we were to try to translate this closure into a more explicit /// form, we'd encounter an error with the code as written: /// /// ``` /// struct Env { x: & &mut isize } /// let x: &mut isize = ...; /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn /// fn fn_ptr(env: &mut Env) { **env.x += 5; } /// ``` /// /// This is then illegal because you cannot mutate a `&mut` found /// in an aliasable location. To solve, you'd have to translate with /// an `&mut` borrow: /// /// ``` /// struct Env { x: & &mut isize } /// let x: &mut isize = ...; /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x /// fn fn_ptr(env: &mut Env) { **env.x += 5; } /// ``` /// /// Now the assignment to `**env.x` is legal, but creating a /// mutable pointer to `x` is not because `x` is not mutable. We /// could fix this by declaring `x` as `let mut x`. This is ok in /// user code, if awkward, but extra weird for closures, since the /// borrow is hidden. /// /// So we introduce a "unique imm" borrow -- the referent is /// immutable, but not aliasable. This solves the problem. For /// simplicity, we don't give users the way to express this /// borrow, it's just used when translating closures. UniqueImmBorrow, /// Data is mutable and not aliasable. MutBorrow, } /// Information describing the capture of an upvar. This is computed /// during `typeck`, specifically by `regionck`. #[derive(PartialEq, Clone, Debug, Copy, TyEncodable, TyDecodable, HashStable)] pub enum UpvarCapture<'tcx> { /// Upvar is captured by value. This is always true when the /// closure is labeled `move`, but can also be true in other cases /// depending on inference. /// /// If the upvar was inferred to be captured by value (e.g. `move` /// was not used), then the `Span` points to a usage that /// required it. There may be more than one such usage /// (e.g. `|| { a; a; }`), in which case we pick an /// arbitrary one. ByValue(Option), /// Upvar is captured by reference. ByRef(UpvarBorrow<'tcx>), } #[derive(PartialEq, Clone, Copy, TyEncodable, TyDecodable, HashStable)] pub struct UpvarBorrow<'tcx> { /// The kind of borrow: by-ref upvars have access to shared /// immutable borrows, which are not part of the normal language /// syntax. pub kind: BorrowKind, /// Region of the resulting reference. pub region: ty::Region<'tcx>, } /// Given the closure DefId this map provides a map of root variables to minimum /// set of `CapturedPlace`s that need to be tracked to support all captures of that closure. pub type MinCaptureInformationMap<'tcx> = FxHashMap>; /// Part of `MinCaptureInformationMap`; Maps a root variable to the list of `CapturedPlace`. /// Used to track the minimum set of `Place`s that need to be captured to support all /// Places captured by the closure starting at a given root variable. /// /// This provides a convenient and quick way of checking if a variable being used within /// a closure is a capture of a local variable. pub type RootVariableMinCaptureList<'tcx> = FxIndexMap>; /// Part of `MinCaptureInformationMap`; List of `CapturePlace`s. pub type MinCaptureList<'tcx> = Vec>; /// A `Place` and the corresponding `CaptureInfo`. #[derive(PartialEq, Clone, Debug, TyEncodable, TyDecodable, HashStable)] pub struct CapturedPlace<'tcx> { pub place: HirPlace<'tcx>, pub info: CaptureInfo<'tcx>, } /// Part of `MinCaptureInformationMap`; describes the capture kind (&, &mut, move) /// for a particular capture as well as identifying the part of the source code /// that triggered this capture to occur. #[derive(PartialEq, Clone, Debug, Copy, TyEncodable, TyDecodable, HashStable)] pub struct CaptureInfo<'tcx> { /// Expr Id pointing to use that resulted in selecting the current capture kind /// /// If the user doesn't enable feature `capture_disjoint_fields` (RFC 2229) then, it is /// possible that we don't see the use of a particular place resulting in expr_id being /// None. In such case we fallback on uvpars_mentioned for span. /// /// Eg: /// ```rust,no_run /// let x = 5; /// /// let c = || { /// let _ = x /// }; /// ``` /// /// In this example, if `capture_disjoint_fields` is **not** set, then x will be captured, /// but we won't see it being used during capture analysis, since it's essentially a discard. pub expr_id: Option, /// Capture mode that was selected pub capture_kind: UpvarCapture<'tcx>, } pub type UpvarListMap = FxHashMap>; pub type UpvarCaptureMap<'tcx> = FxHashMap>; #[derive(Clone, Copy, PartialEq, Eq)] pub enum IntVarValue { IntType(ast::IntTy), UintType(ast::UintTy), } #[derive(Clone, Copy, PartialEq, Eq)] pub struct FloatVarValue(pub ast::FloatTy); impl ty::EarlyBoundRegion { /// Does this early bound region have a name? Early bound regions normally /// always have names except when using anonymous lifetimes (`'_`). pub fn has_name(&self) -> bool { self.name != kw::UnderscoreLifetime } } #[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable)] pub enum GenericParamDefKind { Lifetime, Type { has_default: bool, object_lifetime_default: ObjectLifetimeDefault, synthetic: Option, }, Const, } impl GenericParamDefKind { pub fn descr(&self) -> &'static str { match self { GenericParamDefKind::Lifetime => "lifetime", GenericParamDefKind::Type { .. } => "type", GenericParamDefKind::Const => "constant", } } } #[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable)] pub struct GenericParamDef { pub name: Symbol, pub def_id: DefId, pub index: u32, /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute /// on generic parameter `'a`/`T`, asserts data behind the parameter /// `'a`/`T` won't be accessed during the parent type's `Drop` impl. pub pure_wrt_drop: bool, pub kind: GenericParamDefKind, } impl GenericParamDef { pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion { if let GenericParamDefKind::Lifetime = self.kind { ty::EarlyBoundRegion { def_id: self.def_id, index: self.index, name: self.name } } else { bug!("cannot convert a non-lifetime parameter def to an early bound region") } } } #[derive(Default)] pub struct GenericParamCount { pub lifetimes: usize, pub types: usize, pub consts: usize, } /// Information about the formal type/lifetime parameters associated /// with an item or method. Analogous to `hir::Generics`. /// /// The ordering of parameters is the same as in `Subst` (excluding child generics): /// `Self` (optionally), `Lifetime` params..., `Type` params... #[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable)] pub struct Generics { pub parent: Option, pub parent_count: usize, pub params: Vec, /// Reverse map to the `index` field of each `GenericParamDef`. #[stable_hasher(ignore)] pub param_def_id_to_index: FxHashMap, pub has_self: bool, pub has_late_bound_regions: Option, } impl<'tcx> Generics { pub fn count(&self) -> usize { self.parent_count + self.params.len() } pub fn own_counts(&self) -> GenericParamCount { // We could cache this as a property of `GenericParamCount`, but // the aim is to refactor this away entirely eventually and the // presence of this method will be a constant reminder. let mut own_counts: GenericParamCount = Default::default(); for param in &self.params { match param.kind { GenericParamDefKind::Lifetime => own_counts.lifetimes += 1, GenericParamDefKind::Type { .. } => own_counts.types += 1, GenericParamDefKind::Const => own_counts.consts += 1, }; } own_counts } pub fn requires_monomorphization(&self, tcx: TyCtxt<'tcx>) -> bool { if self.own_requires_monomorphization() { return true; } if let Some(parent_def_id) = self.parent { let parent = tcx.generics_of(parent_def_id); parent.requires_monomorphization(tcx) } else { false } } pub fn own_requires_monomorphization(&self) -> bool { for param in &self.params { match param.kind { GenericParamDefKind::Type { .. } | GenericParamDefKind::Const => return true, GenericParamDefKind::Lifetime => {} } } false } /// Returns the `GenericParamDef` with the given index. pub fn param_at(&'tcx self, param_index: usize, tcx: TyCtxt<'tcx>) -> &'tcx GenericParamDef { if let Some(index) = param_index.checked_sub(self.parent_count) { &self.params[index] } else { tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?")) .param_at(param_index, tcx) } } /// Returns the `GenericParamDef` associated with this `EarlyBoundRegion`. pub fn region_param( &'tcx self, param: &EarlyBoundRegion, tcx: TyCtxt<'tcx>, ) -> &'tcx GenericParamDef { let param = self.param_at(param.index as usize, tcx); match param.kind { GenericParamDefKind::Lifetime => param, _ => bug!("expected lifetime parameter, but found another generic parameter"), } } /// Returns the `GenericParamDef` associated with this `ParamTy`. pub fn type_param(&'tcx self, param: &ParamTy, tcx: TyCtxt<'tcx>) -> &'tcx GenericParamDef { let param = self.param_at(param.index as usize, tcx); match param.kind { GenericParamDefKind::Type { .. } => param, _ => bug!("expected type parameter, but found another generic parameter"), } } /// Returns the `GenericParamDef` associated with this `ParamConst`. pub fn const_param(&'tcx self, param: &ParamConst, tcx: TyCtxt<'tcx>) -> &GenericParamDef { let param = self.param_at(param.index as usize, tcx); match param.kind { GenericParamDefKind::Const => param, _ => bug!("expected const parameter, but found another generic parameter"), } } } /// Bounds on generics. #[derive(Copy, Clone, Default, Debug, TyEncodable, TyDecodable, HashStable)] pub struct GenericPredicates<'tcx> { pub parent: Option, pub predicates: &'tcx [(Predicate<'tcx>, Span)], } impl<'tcx> GenericPredicates<'tcx> { pub fn instantiate( &self, tcx: TyCtxt<'tcx>, substs: SubstsRef<'tcx>, ) -> InstantiatedPredicates<'tcx> { let mut instantiated = InstantiatedPredicates::empty(); self.instantiate_into(tcx, &mut instantiated, substs); instantiated } pub fn instantiate_own( &self, tcx: TyCtxt<'tcx>, substs: SubstsRef<'tcx>, ) -> InstantiatedPredicates<'tcx> { InstantiatedPredicates { predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(), spans: self.predicates.iter().map(|(_, sp)| *sp).collect(), } } fn instantiate_into( &self, tcx: TyCtxt<'tcx>, instantiated: &mut InstantiatedPredicates<'tcx>, substs: SubstsRef<'tcx>, ) { if let Some(def_id) = self.parent { tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs); } instantiated.predicates.extend(self.predicates.iter().map(|(p, _)| p.subst(tcx, substs))); instantiated.spans.extend(self.predicates.iter().map(|(_, sp)| *sp)); } pub fn instantiate_identity(&self, tcx: TyCtxt<'tcx>) -> InstantiatedPredicates<'tcx> { let mut instantiated = InstantiatedPredicates::empty(); self.instantiate_identity_into(tcx, &mut instantiated); instantiated } fn instantiate_identity_into( &self, tcx: TyCtxt<'tcx>, instantiated: &mut InstantiatedPredicates<'tcx>, ) { if let Some(def_id) = self.parent { tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated); } instantiated.predicates.extend(self.predicates.iter().map(|(p, _)| p)); instantiated.spans.extend(self.predicates.iter().map(|(_, s)| s)); } } #[derive(Debug)] crate struct PredicateInner<'tcx> { kind: PredicateKind<'tcx>, flags: TypeFlags, /// See the comment for the corresponding field of [TyS]. outer_exclusive_binder: ty::DebruijnIndex, } #[cfg(target_arch = "x86_64")] static_assert_size!(PredicateInner<'_>, 48); #[derive(Clone, Copy, Lift)] pub struct Predicate<'tcx> { inner: &'tcx PredicateInner<'tcx>, } impl<'tcx> PartialEq for Predicate<'tcx> { fn eq(&self, other: &Self) -> bool { // `self.kind` is always interned. ptr::eq(self.inner, other.inner) } } impl Hash for Predicate<'_> { fn hash(&self, s: &mut H) { (self.inner as *const PredicateInner<'_>).hash(s) } } impl<'tcx> Eq for Predicate<'tcx> {} impl<'tcx> Predicate<'tcx> { #[inline(always)] pub fn kind(self) -> &'tcx PredicateKind<'tcx> { &self.inner.kind } /// Returns the inner `PredicateAtom`. /// /// The returned atom may contain unbound variables bound to binders skipped in this method. /// It is safe to reapply binders to the given atom. /// /// Note that this method panics in case this predicate has unbound variables. pub fn skip_binders(self) -> PredicateAtom<'tcx> { match self.kind() { &PredicateKind::ForAll(binder) => binder.skip_binder(), &PredicateKind::Atom(atom) => { debug_assert!(!atom.has_escaping_bound_vars()); atom } } } /// Returns the inner `PredicateAtom`. /// /// Note that this method does not check if the predicate has unbound variables. /// /// Rebinding the returned atom can causes the previously bound variables /// to end up at the wrong binding level. pub fn skip_binders_unchecked(self) -> PredicateAtom<'tcx> { match self.kind() { &PredicateKind::ForAll(binder) => binder.skip_binder(), &PredicateKind::Atom(atom) => atom, } } /// Converts this to a `Binder>`. If the value was an /// `Atom`, then it is not allowed to contain escaping bound vars. pub fn bound_atom(self) -> Binder> { match self.kind() { &PredicateKind::ForAll(binder) => binder, &PredicateKind::Atom(atom) => { debug_assert!(!atom.has_escaping_bound_vars()); Binder::dummy(atom) } } } /// Allows using a `Binder>` even if the given predicate previously /// contained unbound variables by shifting these variables outwards. pub fn bound_atom_with_opt_escaping(self, tcx: TyCtxt<'tcx>) -> Binder> { match self.kind() { &PredicateKind::ForAll(binder) => binder, &PredicateKind::Atom(atom) => Binder::wrap_nonbinding(tcx, atom), } } } impl<'a, 'tcx> HashStable> for Predicate<'tcx> { fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) { let PredicateInner { ref kind, // The other fields just provide fast access to information that is // also contained in `kind`, so no need to hash them. flags: _, outer_exclusive_binder: _, } = self.inner; kind.hash_stable(hcx, hasher); } } #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)] #[derive(HashStable, TypeFoldable)] pub enum PredicateKind<'tcx> { /// `for<'a>: ...` ForAll(Binder>), Atom(PredicateAtom<'tcx>), } #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)] #[derive(HashStable, TypeFoldable)] pub enum PredicateAtom<'tcx> { /// Corresponds to `where Foo: Bar`. `Foo` here would be /// the `Self` type of the trait reference and `A`, `B`, and `C` /// would be the type parameters. /// /// A trait predicate will have `Constness::Const` if it originates /// from a bound on a `const fn` without the `?const` opt-out (e.g., /// `const fn foobar() {}`). Trait(TraitPredicate<'tcx>, Constness), /// `where 'a: 'b` RegionOutlives(RegionOutlivesPredicate<'tcx>), /// `where T: 'a` TypeOutlives(TypeOutlivesPredicate<'tcx>), /// `where ::Name == X`, approximately. /// See the `ProjectionPredicate` struct for details. Projection(ProjectionPredicate<'tcx>), /// No syntax: `T` well-formed. WellFormed(GenericArg<'tcx>), /// Trait must be object-safe. ObjectSafe(DefId), /// No direct syntax. May be thought of as `where T: FnFoo<...>` /// for some substitutions `...` and `T` being a closure type. /// Satisfied (or refuted) once we know the closure's kind. ClosureKind(DefId, SubstsRef<'tcx>, ClosureKind), /// `T1 <: T2` Subtype(SubtypePredicate<'tcx>), /// Constant initializer must evaluate successfully. ConstEvaluatable(ty::WithOptConstParam, SubstsRef<'tcx>), /// Constants must be equal. The first component is the const that is expected. ConstEquate(&'tcx Const<'tcx>, &'tcx Const<'tcx>), /// Represents a type found in the environment that we can use for implied bounds. /// /// Only used for Chalk. TypeWellFormedFromEnv(Ty<'tcx>), } impl<'tcx> PredicateAtom<'tcx> { /// Wraps `self` with the given qualifier if this predicate has any unbound variables. pub fn potentially_quantified( self, tcx: TyCtxt<'tcx>, qualifier: impl FnOnce(Binder>) -> PredicateKind<'tcx>, ) -> Predicate<'tcx> { if self.has_escaping_bound_vars() { qualifier(Binder::bind(self)) } else { PredicateKind::Atom(self) } .to_predicate(tcx) } } /// The crate outlives map is computed during typeck and contains the /// outlives of every item in the local crate. You should not use it /// directly, because to do so will make your pass dependent on the /// HIR of every item in the local crate. Instead, use /// `tcx.inferred_outlives_of()` to get the outlives for a *particular* /// item. #[derive(HashStable)] pub struct CratePredicatesMap<'tcx> { /// For each struct with outlive bounds, maps to a vector of the /// predicate of its outlive bounds. If an item has no outlives /// bounds, it will have no entry. pub predicates: FxHashMap, Span)]>, } impl<'tcx> Predicate<'tcx> { /// Performs a substitution suitable for going from a /// poly-trait-ref to supertraits that must hold if that /// poly-trait-ref holds. This is slightly different from a normal /// substitution in terms of what happens with bound regions. See /// lengthy comment below for details. pub fn subst_supertrait( self, tcx: TyCtxt<'tcx>, trait_ref: &ty::PolyTraitRef<'tcx>, ) -> Predicate<'tcx> { // The interaction between HRTB and supertraits is not entirely // obvious. Let me walk you (and myself) through an example. // // Let's start with an easy case. Consider two traits: // // trait Foo<'a>: Bar<'a,'a> { } // trait Bar<'b,'c> { } // // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we // knew that `Foo<'x>` (for any 'x) then we also know that // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from // normal substitution. // // In terms of why this is sound, the idea is that whenever there // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>` // holds. So if there is an impl of `T:Foo<'a>` that applies to // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all // `'a`. // // Another example to be careful of is this: // // trait Foo1<'a>: for<'b> Bar1<'a,'b> { } // trait Bar1<'b,'c> { } // // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know? // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The // reason is similar to the previous example: any impl of // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So // basically we would want to collapse the bound lifetimes from // the input (`trait_ref`) and the supertraits. // // To achieve this in practice is fairly straightforward. Let's // consider the more complicated scenario: // // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x` // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`, // where both `'x` and `'b` would have a DB index of 1. // The substitution from the input trait-ref is therefore going to be // `'a => 'x` (where `'x` has a DB index of 1). // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an // early-bound parameter and `'b' is a late-bound parameter with a // DB index of 1. // - If we replace `'a` with `'x` from the input, it too will have // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>` // just as we wanted. // // There is only one catch. If we just apply the substitution `'a // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will // adjust the DB index because we substituting into a binder (it // tries to be so smart...) resulting in `for<'x> for<'b> // Bar1<'x,'b>` (we have no syntax for this, so use your // imagination). Basically the 'x will have DB index of 2 and 'b // will have DB index of 1. Not quite what we want. So we apply // the substitution to the *contents* of the trait reference, // rather than the trait reference itself (put another way, the // substitution code expects equal binding levels in the values // from the substitution and the value being substituted into, and // this trick achieves that). let substs = trait_ref.skip_binder().substs; let pred = self.skip_binders(); let new = pred.subst(tcx, substs); if new != pred { new.potentially_quantified(tcx, PredicateKind::ForAll) } else { self } } } #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)] #[derive(HashStable, TypeFoldable)] pub struct TraitPredicate<'tcx> { pub trait_ref: TraitRef<'tcx>, } pub type PolyTraitPredicate<'tcx> = ty::Binder>; impl<'tcx> TraitPredicate<'tcx> { pub fn def_id(self) -> DefId { self.trait_ref.def_id } pub fn self_ty(self) -> Ty<'tcx> { self.trait_ref.self_ty() } } impl<'tcx> PolyTraitPredicate<'tcx> { pub fn def_id(self) -> DefId { // Ok to skip binder since trait `DefId` does not care about regions. self.skip_binder().def_id() } } #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)] #[derive(HashStable, TypeFoldable)] pub struct OutlivesPredicate(pub A, pub B); // `A: B` pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate, ty::Region<'tcx>>; pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate, ty::Region<'tcx>>; pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder>; pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder>; #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, TyEncodable, TyDecodable)] #[derive(HashStable, TypeFoldable)] pub struct SubtypePredicate<'tcx> { pub a_is_expected: bool, pub a: Ty<'tcx>, pub b: Ty<'tcx>, } pub type PolySubtypePredicate<'tcx> = ty::Binder>; /// This kind of predicate has no *direct* correspondent in the /// syntax, but it roughly corresponds to the syntactic forms: /// /// 1. `T: TraitRef<..., Item = Type>` /// 2. `>::Item == Type` (NYI) /// /// In particular, form #1 is "desugared" to the combination of a /// normal trait predicate (`T: TraitRef<...>`) and one of these /// predicates. Form #2 is a broader form in that it also permits /// equality between arbitrary types. Processing an instance of /// Form #2 eventually yields one of these `ProjectionPredicate` /// instances to normalize the LHS. #[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, TyDecodable)] #[derive(HashStable, TypeFoldable)] pub struct ProjectionPredicate<'tcx> { pub projection_ty: ProjectionTy<'tcx>, pub ty: Ty<'tcx>, } pub type PolyProjectionPredicate<'tcx> = Binder>; impl<'tcx> PolyProjectionPredicate<'tcx> { /// Returns the `DefId` of the associated item being projected. pub fn item_def_id(&self) -> DefId { self.skip_binder().projection_ty.item_def_id } #[inline] pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'tcx>) -> PolyTraitRef<'tcx> { // Note: unlike with `TraitRef::to_poly_trait_ref()`, // `self.0.trait_ref` is permitted to have escaping regions. // This is because here `self` has a `Binder` and so does our // return value, so we are preserving the number of binding // levels. self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx)) } pub fn ty(&self) -> Binder> { self.map_bound(|predicate| predicate.ty) } /// The `DefId` of the `TraitItem` for the associated type. /// /// Note that this is not the `DefId` of the `TraitRef` containing this /// associated type, which is in `tcx.associated_item(projection_def_id()).container`. pub fn projection_def_id(&self) -> DefId { // Ok to skip binder since trait `DefId` does not care about regions. self.skip_binder().projection_ty.item_def_id } } pub trait ToPolyTraitRef<'tcx> { fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>; } impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> { fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> { ty::Binder::dummy(*self) } } impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> { fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> { self.map_bound_ref(|trait_pred| trait_pred.trait_ref) } } pub trait ToPredicate<'tcx> { fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx>; } impl ToPredicate<'tcx> for PredicateKind<'tcx> { #[inline(always)] fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> { tcx.mk_predicate(self) } } impl ToPredicate<'tcx> for PredicateAtom<'tcx> { #[inline(always)] fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> { debug_assert!(!self.has_escaping_bound_vars(), "escaping bound vars for {:?}", self); tcx.mk_predicate(PredicateKind::Atom(self)) } } impl<'tcx> ToPredicate<'tcx> for ConstnessAnd> { fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> { PredicateAtom::Trait(ty::TraitPredicate { trait_ref: self.value }, self.constness) .to_predicate(tcx) } } impl<'tcx> ToPredicate<'tcx> for ConstnessAnd> { fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> { ConstnessAnd { value: self.value.map_bound(|trait_ref| ty::TraitPredicate { trait_ref }), constness: self.constness, } .to_predicate(tcx) } } impl<'tcx> ToPredicate<'tcx> for ConstnessAnd> { fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> { PredicateAtom::Trait(self.value.skip_binder(), self.constness) .potentially_quantified(tcx, PredicateKind::ForAll) } } impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> { fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> { PredicateAtom::RegionOutlives(self.skip_binder()) .potentially_quantified(tcx, PredicateKind::ForAll) } } impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> { fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> { PredicateAtom::TypeOutlives(self.skip_binder()) .potentially_quantified(tcx, PredicateKind::ForAll) } } impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> { fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> { PredicateAtom::Projection(self.skip_binder()) .potentially_quantified(tcx, PredicateKind::ForAll) } } impl<'tcx> Predicate<'tcx> { pub fn to_opt_poly_trait_ref(self) -> Option>> { match self.skip_binders() { PredicateAtom::Trait(t, constness) => { Some(ConstnessAnd { constness, value: ty::Binder::bind(t.trait_ref) }) } PredicateAtom::Projection(..) | PredicateAtom::Subtype(..) | PredicateAtom::RegionOutlives(..) | PredicateAtom::WellFormed(..) | PredicateAtom::ObjectSafe(..) | PredicateAtom::ClosureKind(..) | PredicateAtom::TypeOutlives(..) | PredicateAtom::ConstEvaluatable(..) | PredicateAtom::ConstEquate(..) | PredicateAtom::TypeWellFormedFromEnv(..) => None, } } pub fn to_opt_type_outlives(self) -> Option> { match self.skip_binders() { PredicateAtom::TypeOutlives(data) => Some(ty::Binder::bind(data)), PredicateAtom::Trait(..) | PredicateAtom::Projection(..) | PredicateAtom::Subtype(..) | PredicateAtom::RegionOutlives(..) | PredicateAtom::WellFormed(..) | PredicateAtom::ObjectSafe(..) | PredicateAtom::ClosureKind(..) | PredicateAtom::ConstEvaluatable(..) | PredicateAtom::ConstEquate(..) | PredicateAtom::TypeWellFormedFromEnv(..) => None, } } } /// Represents the bounds declared on a particular set of type /// parameters. Should eventually be generalized into a flag list of /// where-clauses. You can obtain a `InstantiatedPredicates` list from a /// `GenericPredicates` by using the `instantiate` method. Note that this method /// reflects an important semantic invariant of `InstantiatedPredicates`: while /// the `GenericPredicates` are expressed in terms of the bound type /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance /// represented a set of bounds for some particular instantiation, /// meaning that the generic parameters have been substituted with /// their values. /// /// Example: /// /// struct Foo> { ... } /// /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like /// `[[], [U:Bar]]`. Now if there were some particular reference /// like `Foo`, then the `InstantiatedPredicates` would be `[[], /// [usize:Bar]]`. #[derive(Clone, Debug, TypeFoldable)] pub struct InstantiatedPredicates<'tcx> { pub predicates: Vec>, pub spans: Vec, } impl<'tcx> InstantiatedPredicates<'tcx> { pub fn empty() -> InstantiatedPredicates<'tcx> { InstantiatedPredicates { predicates: vec![], spans: vec![] } } pub fn is_empty(&self) -> bool { self.predicates.is_empty() } } rustc_index::newtype_index! { /// "Universes" are used during type- and trait-checking in the /// presence of `for<..>` binders to control what sets of names are /// visible. Universes are arranged into a tree: the root universe /// contains names that are always visible. Each child then adds a new /// set of names that are visible, in addition to those of its parent. /// We say that the child universe "extends" the parent universe with /// new names. /// /// To make this more concrete, consider this program: /// /// ``` /// struct Foo { } /// fn bar(x: T) { /// let y: for<'a> fn(&'a u8, Foo) = ...; /// } /// ``` /// /// The struct name `Foo` is in the root universe U0. But the type /// parameter `T`, introduced on `bar`, is in an extended universe U1 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside /// of `bar`, we cannot name `T`. Then, within the type of `y`, the /// region `'a` is in a universe U2 that extends U1, because we can /// name it inside the fn type but not outside. /// /// Universes are used to do type- and trait-checking around these /// "forall" binders (also called **universal quantification**). The /// idea is that when, in the body of `bar`, we refer to `T` as a /// type, we aren't referring to any type in particular, but rather a /// kind of "fresh" type that is distinct from all other types we have /// actually declared. This is called a **placeholder** type, and we /// use universes to talk about this. In other words, a type name in /// universe 0 always corresponds to some "ground" type that the user /// declared, but a type name in a non-zero universe is a placeholder /// type -- an idealized representative of "types in general" that we /// use for checking generic functions. pub struct UniverseIndex { derive [HashStable] DEBUG_FORMAT = "U{}", } } impl UniverseIndex { pub const ROOT: UniverseIndex = UniverseIndex::from_u32(0); /// Returns the "next" universe index in order -- this new index /// is considered to extend all previous universes. This /// corresponds to entering a `forall` quantifier. So, for /// example, suppose we have this type in universe `U`: /// /// ``` /// for<'a> fn(&'a u32) /// ``` /// /// Once we "enter" into this `for<'a>` quantifier, we are in a /// new universe that extends `U` -- in this new universe, we can /// name the region `'a`, but that region was not nameable from /// `U` because it was not in scope there. pub fn next_universe(self) -> UniverseIndex { UniverseIndex::from_u32(self.private.checked_add(1).unwrap()) } /// Returns `true` if `self` can name a name from `other` -- in other words, /// if the set of names in `self` is a superset of those in /// `other` (`self >= other`). pub fn can_name(self, other: UniverseIndex) -> bool { self.private >= other.private } /// Returns `true` if `self` cannot name some names from `other` -- in other /// words, if the set of names in `self` is a strict subset of /// those in `other` (`self < other`). pub fn cannot_name(self, other: UniverseIndex) -> bool { self.private < other.private } } /// The "placeholder index" fully defines a placeholder region, type, or const. Placeholders are /// identified by both a universe, as well as a name residing within that universe. Distinct bound /// regions/types/consts within the same universe simply have an unknown relationship to one /// another. #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable, PartialOrd, Ord)] pub struct Placeholder { pub universe: UniverseIndex, pub name: T, } impl<'a, T> HashStable> for Placeholder where T: HashStable>, { fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) { self.universe.hash_stable(hcx, hasher); self.name.hash_stable(hcx, hasher); } } pub type PlaceholderRegion = Placeholder; pub type PlaceholderType = Placeholder; #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable)] #[derive(TyEncodable, TyDecodable, PartialOrd, Ord)] pub struct BoundConst<'tcx> { pub var: BoundVar, pub ty: Ty<'tcx>, } pub type PlaceholderConst<'tcx> = Placeholder>; /// A `DefId` which is potentially bundled with its corresponding generic parameter /// in case `did` is a const argument. /// /// This is used to prevent cycle errors during typeck /// as `type_of(const_arg)` depends on `typeck(owning_body)` /// which once again requires the type of its generic arguments. /// /// Luckily we only need to deal with const arguments once we /// know their corresponding parameters. We (ab)use this by /// calling `type_of(param_did)` for these arguments. /// /// ```rust /// #![feature(const_generics)] /// /// struct A; /// impl A { /// fn foo(&self) -> usize { N } /// } /// struct B; /// impl B { /// fn foo(&self) -> usize { 42 } /// } /// /// fn main() { /// let a = A; /// a.foo::<7>(); /// } /// ``` #[derive(Copy, Clone, Debug, TypeFoldable, Lift, TyEncodable, TyDecodable)] #[derive(PartialEq, Eq, PartialOrd, Ord)] #[derive(Hash, HashStable)] pub struct WithOptConstParam { pub did: T, /// The `DefId` of the corresponding generic parameter in case `did` is /// a const argument. /// /// Note that even if `did` is a const argument, this may still be `None`. /// All queries taking `WithOptConstParam` start by calling `tcx.opt_const_param_of(def.did)` /// to potentially update `param_did` in case it `None`. pub const_param_did: Option, } impl WithOptConstParam { /// Creates a new `WithOptConstParam` setting `const_param_did` to `None`. #[inline(always)] pub fn unknown(did: T) -> WithOptConstParam { WithOptConstParam { did, const_param_did: None } } } impl WithOptConstParam { /// Returns `Some((did, param_did))` if `def_id` is a const argument, /// `None` otherwise. #[inline(always)] pub fn try_lookup(did: LocalDefId, tcx: TyCtxt<'_>) -> Option<(LocalDefId, DefId)> { tcx.opt_const_param_of(did).map(|param_did| (did, param_did)) } /// In case `self` is unknown but `self.did` is a const argument, this returns /// a `WithOptConstParam` with the correct `const_param_did`. #[inline(always)] pub fn try_upgrade(self, tcx: TyCtxt<'_>) -> Option> { if self.const_param_did.is_none() { if let const_param_did @ Some(_) = tcx.opt_const_param_of(self.did) { return Some(WithOptConstParam { did: self.did, const_param_did }); } } None } pub fn to_global(self) -> WithOptConstParam { WithOptConstParam { did: self.did.to_def_id(), const_param_did: self.const_param_did } } pub fn def_id_for_type_of(self) -> DefId { if let Some(did) = self.const_param_did { did } else { self.did.to_def_id() } } } impl WithOptConstParam { pub fn as_local(self) -> Option> { self.did .as_local() .map(|did| WithOptConstParam { did, const_param_did: self.const_param_did }) } pub fn as_const_arg(self) -> Option<(LocalDefId, DefId)> { if let Some(param_did) = self.const_param_did { if let Some(did) = self.did.as_local() { return Some((did, param_did)); } } None } pub fn expect_local(self) -> WithOptConstParam { self.as_local().unwrap() } pub fn is_local(self) -> bool { self.did.is_local() } pub fn def_id_for_type_of(self) -> DefId { self.const_param_did.unwrap_or(self.did) } } /// When type checking, we use the `ParamEnv` to track /// details about the set of where-clauses that are in scope at this /// particular point. #[derive(Copy, Clone, Hash, PartialEq, Eq)] pub struct ParamEnv<'tcx> { /// This packs both caller bounds and the reveal enum into one pointer. /// /// Caller bounds are `Obligation`s that the caller must satisfy. This is /// basically the set of bounds on the in-scope type parameters, translated /// into `Obligation`s, and elaborated and normalized. /// /// Use the `caller_bounds()` method to access. /// /// Typically, this is `Reveal::UserFacing`, but during codegen we /// want `Reveal::All`. /// /// Note: This is packed, use the reveal() method to access it. packed: CopyTaggedPtr<&'tcx List>, traits::Reveal, true>, } unsafe impl rustc_data_structures::tagged_ptr::Tag for traits::Reveal { const BITS: usize = 1; fn into_usize(self) -> usize { match self { traits::Reveal::UserFacing => 0, traits::Reveal::All => 1, } } unsafe fn from_usize(ptr: usize) -> Self { match ptr { 0 => traits::Reveal::UserFacing, 1 => traits::Reveal::All, _ => std::hint::unreachable_unchecked(), } } } impl<'tcx> fmt::Debug for ParamEnv<'tcx> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.debug_struct("ParamEnv") .field("caller_bounds", &self.caller_bounds()) .field("reveal", &self.reveal()) .finish() } } impl<'a, 'tcx> HashStable> for ParamEnv<'tcx> { fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) { self.caller_bounds().hash_stable(hcx, hasher); self.reveal().hash_stable(hcx, hasher); } } impl<'tcx> TypeFoldable<'tcx> for ParamEnv<'tcx> { fn super_fold_with>(self, folder: &mut F) -> Self { ParamEnv::new(self.caller_bounds().fold_with(folder), self.reveal().fold_with(folder)) } fn super_visit_with>(&self, visitor: &mut V) -> ControlFlow { self.caller_bounds().visit_with(visitor)?; self.reveal().visit_with(visitor) } } impl<'tcx> ParamEnv<'tcx> { /// Construct a trait environment suitable for contexts where /// there are no where-clauses in scope. Hidden types (like `impl /// Trait`) are left hidden, so this is suitable for ordinary /// type-checking. #[inline] pub fn empty() -> Self { Self::new(List::empty(), Reveal::UserFacing) } #[inline] pub fn caller_bounds(self) -> &'tcx List> { self.packed.pointer() } #[inline] pub fn reveal(self) -> traits::Reveal { self.packed.tag() } /// Construct a trait environment with no where-clauses in scope /// where the values of all `impl Trait` and other hidden types /// are revealed. This is suitable for monomorphized, post-typeck /// environments like codegen or doing optimizations. /// /// N.B., if you want to have predicates in scope, use `ParamEnv::new`, /// or invoke `param_env.with_reveal_all()`. #[inline] pub fn reveal_all() -> Self { Self::new(List::empty(), Reveal::All) } /// Construct a trait environment with the given set of predicates. #[inline] pub fn new(caller_bounds: &'tcx List>, reveal: Reveal) -> Self { ty::ParamEnv { packed: CopyTaggedPtr::new(caller_bounds, reveal) } } pub fn with_user_facing(mut self) -> Self { self.packed.set_tag(Reveal::UserFacing); self } /// Returns a new parameter environment with the same clauses, but /// which "reveals" the true results of projections in all cases /// (even for associated types that are specializable). This is /// the desired behavior during codegen and certain other special /// contexts; normally though we want to use `Reveal::UserFacing`, /// which is the default. /// All opaque types in the caller_bounds of the `ParamEnv` /// will be normalized to their underlying types. /// See PR #65989 and issue #65918 for more details pub fn with_reveal_all_normalized(self, tcx: TyCtxt<'tcx>) -> Self { if self.packed.tag() == traits::Reveal::All { return self; } ParamEnv::new(tcx.normalize_opaque_types(self.caller_bounds()), Reveal::All) } /// Returns this same environment but with no caller bounds. pub fn without_caller_bounds(self) -> Self { Self::new(List::empty(), self.reveal()) } /// Creates a suitable environment in which to perform trait /// queries on the given value. When type-checking, this is simply /// the pair of the environment plus value. But when reveal is set to /// All, then if `value` does not reference any type parameters, we will /// pair it with the empty environment. This improves caching and is generally /// invisible. /// /// N.B., we preserve the environment when type-checking because it /// is possible for the user to have wacky where-clauses like /// `where Box: Copy`, which are clearly never /// satisfiable. We generally want to behave as if they were true, /// although the surrounding function is never reachable. pub fn and>(self, value: T) -> ParamEnvAnd<'tcx, T> { match self.reveal() { Reveal::UserFacing => ParamEnvAnd { param_env: self, value }, Reveal::All => { if value.is_global() { ParamEnvAnd { param_env: self.without_caller_bounds(), value } } else { ParamEnvAnd { param_env: self, value } } } } } } #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TypeFoldable)] pub struct ConstnessAnd { pub constness: Constness, pub value: T, } // FIXME(ecstaticmorse): Audit all occurrences of `without_const().to_predicate(tcx)` to ensure that // the constness of trait bounds is being propagated correctly. pub trait WithConstness: Sized { #[inline] fn with_constness(self, constness: Constness) -> ConstnessAnd { ConstnessAnd { constness, value: self } } #[inline] fn with_const(self) -> ConstnessAnd { self.with_constness(Constness::Const) } #[inline] fn without_const(self) -> ConstnessAnd { self.with_constness(Constness::NotConst) } } impl WithConstness for T {} #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TypeFoldable)] pub struct ParamEnvAnd<'tcx, T> { pub param_env: ParamEnv<'tcx>, pub value: T, } impl<'tcx, T> ParamEnvAnd<'tcx, T> { pub fn into_parts(self) -> (ParamEnv<'tcx>, T) { (self.param_env, self.value) } } impl<'a, 'tcx, T> HashStable> for ParamEnvAnd<'tcx, T> where T: HashStable>, { fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) { let ParamEnvAnd { ref param_env, ref value } = *self; param_env.hash_stable(hcx, hasher); value.hash_stable(hcx, hasher); } } #[derive(Copy, Clone, Debug, HashStable)] pub struct Destructor { /// The `DefId` of the destructor method pub did: DefId, } bitflags! { #[derive(HashStable)] pub struct AdtFlags: u32 { const NO_ADT_FLAGS = 0; /// Indicates whether the ADT is an enum. const IS_ENUM = 1 << 0; /// Indicates whether the ADT is a union. const IS_UNION = 1 << 1; /// Indicates whether the ADT is a struct. const IS_STRUCT = 1 << 2; /// Indicates whether the ADT is a struct and has a constructor. const HAS_CTOR = 1 << 3; /// Indicates whether the type is `PhantomData`. const IS_PHANTOM_DATA = 1 << 4; /// Indicates whether the type has a `#[fundamental]` attribute. const IS_FUNDAMENTAL = 1 << 5; /// Indicates whether the type is `Box`. const IS_BOX = 1 << 6; /// Indicates whether the type is `ManuallyDrop`. const IS_MANUALLY_DROP = 1 << 7; /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`. /// (i.e., this flag is never set unless this ADT is an enum). const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 8; } } bitflags! { #[derive(HashStable)] pub struct VariantFlags: u32 { const NO_VARIANT_FLAGS = 0; /// Indicates whether the field list of this variant is `#[non_exhaustive]`. const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0; /// Indicates whether this variant was obtained as part of recovering from /// a syntactic error. May be incomplete or bogus. const IS_RECOVERED = 1 << 1; } } /// Definition of a variant -- a struct's fields or a enum variant. #[derive(Debug, HashStable)] pub struct VariantDef { /// `DefId` that identifies the variant itself. /// If this variant belongs to a struct or union, then this is a copy of its `DefId`. pub def_id: DefId, /// `DefId` that identifies the variant's constructor. /// If this variant is a struct variant, then this is `None`. pub ctor_def_id: Option, /// Variant or struct name. #[stable_hasher(project(name))] pub ident: Ident, /// Discriminant of this variant. pub discr: VariantDiscr, /// Fields of this variant. pub fields: Vec, /// Type of constructor of variant. pub ctor_kind: CtorKind, /// Flags of the variant (e.g. is field list non-exhaustive)? flags: VariantFlags, } impl VariantDef { /// Creates a new `VariantDef`. /// /// `variant_did` is the `DefId` that identifies the enum variant (if this `VariantDef` /// represents an enum variant). /// /// `ctor_did` is the `DefId` that identifies the constructor of unit or /// tuple-variants/structs. If this is a `struct`-variant then this should be `None`. /// /// `parent_did` is the `DefId` of the `AdtDef` representing the enum or struct that /// owns this variant. It is used for checking if a struct has `#[non_exhaustive]` w/out having /// to go through the redirect of checking the ctor's attributes - but compiling a small crate /// requires loading the `AdtDef`s for all the structs in the universe (e.g., coherence for any /// built-in trait), and we do not want to load attributes twice. /// /// If someone speeds up attribute loading to not be a performance concern, they can /// remove this hack and use the constructor `DefId` everywhere. pub fn new( ident: Ident, variant_did: Option, ctor_def_id: Option, discr: VariantDiscr, fields: Vec, ctor_kind: CtorKind, adt_kind: AdtKind, parent_did: DefId, recovered: bool, is_field_list_non_exhaustive: bool, ) -> Self { debug!( "VariantDef::new(ident = {:?}, variant_did = {:?}, ctor_def_id = {:?}, discr = {:?}, fields = {:?}, ctor_kind = {:?}, adt_kind = {:?}, parent_did = {:?})", ident, variant_did, ctor_def_id, discr, fields, ctor_kind, adt_kind, parent_did, ); let mut flags = VariantFlags::NO_VARIANT_FLAGS; if is_field_list_non_exhaustive { flags |= VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE; } if recovered { flags |= VariantFlags::IS_RECOVERED; } VariantDef { def_id: variant_did.unwrap_or(parent_did), ctor_def_id, ident, discr, fields, ctor_kind, flags, } } /// Is this field list non-exhaustive? #[inline] pub fn is_field_list_non_exhaustive(&self) -> bool { self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE) } /// Was this variant obtained as part of recovering from a syntactic error? #[inline] pub fn is_recovered(&self) -> bool { self.flags.intersects(VariantFlags::IS_RECOVERED) } } #[derive(Copy, Clone, Debug, PartialEq, Eq, TyEncodable, TyDecodable, HashStable)] pub enum VariantDiscr { /// Explicit value for this variant, i.e., `X = 123`. /// The `DefId` corresponds to the embedded constant. Explicit(DefId), /// The previous variant's discriminant plus one. /// For efficiency reasons, the distance from the /// last `Explicit` discriminant is being stored, /// or `0` for the first variant, if it has none. Relative(u32), } #[derive(Debug, HashStable)] pub struct FieldDef { pub did: DefId, #[stable_hasher(project(name))] pub ident: Ident, pub vis: Visibility, } /// The definition of a user-defined type, e.g., a `struct`, `enum`, or `union`. /// /// These are all interned (by `alloc_adt_def`) into the global arena. /// /// The initialism *ADT* stands for an [*algebraic data type (ADT)*][adt]. /// This is slightly wrong because `union`s are not ADTs. /// Moreover, Rust only allows recursive data types through indirection. /// /// [adt]: https://en.wikipedia.org/wiki/Algebraic_data_type pub struct AdtDef { /// The `DefId` of the struct, enum or union item. pub did: DefId, /// Variants of the ADT. If this is a struct or union, then there will be a single variant. pub variants: IndexVec, /// Flags of the ADT (e.g., is this a struct? is this non-exhaustive?). flags: AdtFlags, /// Repr options provided by the user. pub repr: ReprOptions, } impl PartialOrd for AdtDef { fn partial_cmp(&self, other: &AdtDef) -> Option { Some(self.cmp(&other)) } } /// There should be only one AdtDef for each `did`, therefore /// it is fine to implement `Ord` only based on `did`. impl Ord for AdtDef { fn cmp(&self, other: &AdtDef) -> Ordering { self.did.cmp(&other.did) } } impl PartialEq for AdtDef { // `AdtDef`s are always interned, and this is part of `TyS` equality. #[inline] fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) } } impl Eq for AdtDef {} impl Hash for AdtDef { #[inline] fn hash(&self, s: &mut H) { (self as *const AdtDef).hash(s) } } impl Encodable for AdtDef { fn encode(&self, s: &mut S) -> Result<(), S::Error> { self.did.encode(s) } } impl<'a> HashStable> for AdtDef { fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) { thread_local! { static CACHE: RefCell> = Default::default(); } let hash: Fingerprint = CACHE.with(|cache| { let addr = self as *const AdtDef as usize; *cache.borrow_mut().entry(addr).or_insert_with(|| { let ty::AdtDef { did, ref variants, ref flags, ref repr } = *self; let mut hasher = StableHasher::new(); did.hash_stable(hcx, &mut hasher); variants.hash_stable(hcx, &mut hasher); flags.hash_stable(hcx, &mut hasher); repr.hash_stable(hcx, &mut hasher); hasher.finish() }) }); hash.hash_stable(hcx, hasher); } } #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)] pub enum AdtKind { Struct, Union, Enum, } impl Into for AdtKind { fn into(self) -> DataTypeKind { match self { AdtKind::Struct => DataTypeKind::Struct, AdtKind::Union => DataTypeKind::Union, AdtKind::Enum => DataTypeKind::Enum, } } } bitflags! { #[derive(TyEncodable, TyDecodable, Default, HashStable)] pub struct ReprFlags: u8 { const IS_C = 1 << 0; const IS_SIMD = 1 << 1; const IS_TRANSPARENT = 1 << 2; // Internal only for now. If true, don't reorder fields. const IS_LINEAR = 1 << 3; // If true, don't expose any niche to type's context. const HIDE_NICHE = 1 << 4; // Any of these flags being set prevent field reordering optimisation. const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits | ReprFlags::IS_SIMD.bits | ReprFlags::IS_LINEAR.bits; } } /// Represents the repr options provided by the user, #[derive(Copy, Clone, Debug, Eq, PartialEq, TyEncodable, TyDecodable, Default, HashStable)] pub struct ReprOptions { pub int: Option, pub align: Option, pub pack: Option, pub flags: ReprFlags, } impl ReprOptions { pub fn new(tcx: TyCtxt<'_>, did: DefId) -> ReprOptions { let mut flags = ReprFlags::empty(); let mut size = None; let mut max_align: Option = None; let mut min_pack: Option = None; for attr in tcx.get_attrs(did).iter() { for r in attr::find_repr_attrs(&tcx.sess, attr) { flags.insert(match r { attr::ReprC => ReprFlags::IS_C, attr::ReprPacked(pack) => { let pack = Align::from_bytes(pack as u64).unwrap(); min_pack = Some(if let Some(min_pack) = min_pack { min_pack.min(pack) } else { pack }); ReprFlags::empty() } attr::ReprTransparent => ReprFlags::IS_TRANSPARENT, attr::ReprNoNiche => ReprFlags::HIDE_NICHE, attr::ReprSimd => ReprFlags::IS_SIMD, attr::ReprInt(i) => { size = Some(i); ReprFlags::empty() } attr::ReprAlign(align) => { max_align = max_align.max(Some(Align::from_bytes(align as u64).unwrap())); ReprFlags::empty() } }); } } // This is here instead of layout because the choice must make it into metadata. if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.def_path_str(did))) { flags.insert(ReprFlags::IS_LINEAR); } ReprOptions { int: size, align: max_align, pack: min_pack, flags } } #[inline] pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) } #[inline] pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) } #[inline] pub fn packed(&self) -> bool { self.pack.is_some() } #[inline] pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) } #[inline] pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) } #[inline] pub fn hide_niche(&self) -> bool { self.flags.contains(ReprFlags::HIDE_NICHE) } /// Returns the discriminant type, given these `repr` options. /// This must only be called on enums! pub fn discr_type(&self) -> attr::IntType { self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize)) } /// Returns `true` if this `#[repr()]` should inhabit "smart enum /// layout" optimizations, such as representing `Foo<&T>` as a /// single pointer. pub fn inhibit_enum_layout_opt(&self) -> bool { self.c() || self.int.is_some() } /// Returns `true` if this `#[repr()]` should inhibit struct field reordering /// optimizations, such as with `repr(C)`, `repr(packed(1))`, or `repr()`. pub fn inhibit_struct_field_reordering_opt(&self) -> bool { if let Some(pack) = self.pack { if pack.bytes() == 1 { return true; } } self.flags.intersects(ReprFlags::IS_UNOPTIMISABLE) || self.int.is_some() } /// Returns `true` if this `#[repr()]` should inhibit union ABI optimisations. pub fn inhibit_union_abi_opt(&self) -> bool { self.c() } } impl<'tcx> AdtDef { /// Creates a new `AdtDef`. fn new( tcx: TyCtxt<'_>, did: DefId, kind: AdtKind, variants: IndexVec, repr: ReprOptions, ) -> Self { debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr); let mut flags = AdtFlags::NO_ADT_FLAGS; if kind == AdtKind::Enum && tcx.has_attr(did, sym::non_exhaustive) { debug!("found non-exhaustive variant list for {:?}", did); flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE; } flags |= match kind { AdtKind::Enum => AdtFlags::IS_ENUM, AdtKind::Union => AdtFlags::IS_UNION, AdtKind::Struct => AdtFlags::IS_STRUCT, }; if kind == AdtKind::Struct && variants[VariantIdx::new(0)].ctor_def_id.is_some() { flags |= AdtFlags::HAS_CTOR; } let attrs = tcx.get_attrs(did); if tcx.sess.contains_name(&attrs, sym::fundamental) { flags |= AdtFlags::IS_FUNDAMENTAL; } if Some(did) == tcx.lang_items().phantom_data() { flags |= AdtFlags::IS_PHANTOM_DATA; } if Some(did) == tcx.lang_items().owned_box() { flags |= AdtFlags::IS_BOX; } if Some(did) == tcx.lang_items().manually_drop() { flags |= AdtFlags::IS_MANUALLY_DROP; } AdtDef { did, variants, flags, repr } } /// Returns `true` if this is a struct. #[inline] pub fn is_struct(&self) -> bool { self.flags.contains(AdtFlags::IS_STRUCT) } /// Returns `true` if this is a union. #[inline] pub fn is_union(&self) -> bool { self.flags.contains(AdtFlags::IS_UNION) } /// Returns `true` if this is a enum. #[inline] pub fn is_enum(&self) -> bool { self.flags.contains(AdtFlags::IS_ENUM) } /// Returns `true` if the variant list of this ADT is `#[non_exhaustive]`. #[inline] pub fn is_variant_list_non_exhaustive(&self) -> bool { self.flags.contains(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE) } /// Returns the kind of the ADT. #[inline] pub fn adt_kind(&self) -> AdtKind { if self.is_enum() { AdtKind::Enum } else if self.is_union() { AdtKind::Union } else { AdtKind::Struct } } /// Returns a description of this abstract data type. pub fn descr(&self) -> &'static str { match self.adt_kind() { AdtKind::Struct => "struct", AdtKind::Union => "union", AdtKind::Enum => "enum", } } /// Returns a description of a variant of this abstract data type. #[inline] pub fn variant_descr(&self) -> &'static str { match self.adt_kind() { AdtKind::Struct => "struct", AdtKind::Union => "union", AdtKind::Enum => "variant", } } /// If this function returns `true`, it implies that `is_struct` must return `true`. #[inline] pub fn has_ctor(&self) -> bool { self.flags.contains(AdtFlags::HAS_CTOR) } /// Returns `true` if this type is `#[fundamental]` for the purposes /// of coherence checking. #[inline] pub fn is_fundamental(&self) -> bool { self.flags.contains(AdtFlags::IS_FUNDAMENTAL) } /// Returns `true` if this is `PhantomData`. #[inline] pub fn is_phantom_data(&self) -> bool { self.flags.contains(AdtFlags::IS_PHANTOM_DATA) } /// Returns `true` if this is Box. #[inline] pub fn is_box(&self) -> bool { self.flags.contains(AdtFlags::IS_BOX) } /// Returns `true` if this is `ManuallyDrop`. #[inline] pub fn is_manually_drop(&self) -> bool { self.flags.contains(AdtFlags::IS_MANUALLY_DROP) } /// Returns `true` if this type has a destructor. pub fn has_dtor(&self, tcx: TyCtxt<'tcx>) -> bool { self.destructor(tcx).is_some() } /// Asserts this is a struct or union and returns its unique variant. pub fn non_enum_variant(&self) -> &VariantDef { assert!(self.is_struct() || self.is_union()); &self.variants[VariantIdx::new(0)] } #[inline] pub fn predicates(&self, tcx: TyCtxt<'tcx>) -> GenericPredicates<'tcx> { tcx.predicates_of(self.did) } /// Returns an iterator over all fields contained /// by this ADT. #[inline] pub fn all_fields(&self) -> impl Iterator + Clone { self.variants.iter().flat_map(|v| v.fields.iter()) } /// Whether the ADT lacks fields. Note that this includes uninhabited enums, /// e.g., `enum Void {}` is considered payload free as well. pub fn is_payloadfree(&self) -> bool { self.variants.iter().all(|v| v.fields.is_empty()) } /// Return a `VariantDef` given a variant id. pub fn variant_with_id(&self, vid: DefId) -> &VariantDef { self.variants.iter().find(|v| v.def_id == vid).expect("variant_with_id: unknown variant") } /// Return a `VariantDef` given a constructor id. pub fn variant_with_ctor_id(&self, cid: DefId) -> &VariantDef { self.variants .iter() .find(|v| v.ctor_def_id == Some(cid)) .expect("variant_with_ctor_id: unknown variant") } /// Return the index of `VariantDef` given a variant id. pub fn variant_index_with_id(&self, vid: DefId) -> VariantIdx { self.variants .iter_enumerated() .find(|(_, v)| v.def_id == vid) .expect("variant_index_with_id: unknown variant") .0 } /// Return the index of `VariantDef` given a constructor id. pub fn variant_index_with_ctor_id(&self, cid: DefId) -> VariantIdx { self.variants .iter_enumerated() .find(|(_, v)| v.ctor_def_id == Some(cid)) .expect("variant_index_with_ctor_id: unknown variant") .0 } pub fn variant_of_res(&self, res: Res) -> &VariantDef { match res { Res::Def(DefKind::Variant, vid) => self.variant_with_id(vid), Res::Def(DefKind::Ctor(..), cid) => self.variant_with_ctor_id(cid), Res::Def(DefKind::Struct, _) | Res::Def(DefKind::Union, _) | Res::Def(DefKind::TyAlias, _) | Res::Def(DefKind::AssocTy, _) | Res::SelfTy(..) | Res::SelfCtor(..) => self.non_enum_variant(), _ => bug!("unexpected res {:?} in variant_of_res", res), } } #[inline] pub fn eval_explicit_discr(&self, tcx: TyCtxt<'tcx>, expr_did: DefId) -> Option> { assert!(self.is_enum()); let param_env = tcx.param_env(expr_did); let repr_type = self.repr.discr_type(); match tcx.const_eval_poly(expr_did) { Ok(val) => { let ty = repr_type.to_ty(tcx); if let Some(b) = val.try_to_bits_for_ty(tcx, param_env, ty) { trace!("discriminants: {} ({:?})", b, repr_type); Some(Discr { val: b, ty }) } else { info!("invalid enum discriminant: {:#?}", val); crate::mir::interpret::struct_error( tcx.at(tcx.def_span(expr_did)), "constant evaluation of enum discriminant resulted in non-integer", ) .emit(); None } } Err(err) => { let msg = match err { ErrorHandled::Reported(ErrorReported) | ErrorHandled::Linted => { "enum discriminant evaluation failed" } ErrorHandled::TooGeneric => "enum discriminant depends on generics", }; tcx.sess.delay_span_bug(tcx.def_span(expr_did), msg); None } } } #[inline] pub fn discriminants( &'tcx self, tcx: TyCtxt<'tcx>, ) -> impl Iterator)> + Captures<'tcx> { assert!(self.is_enum()); let repr_type = self.repr.discr_type(); let initial = repr_type.initial_discriminant(tcx); let mut prev_discr = None::>; self.variants.iter_enumerated().map(move |(i, v)| { let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx)); if let VariantDiscr::Explicit(expr_did) = v.discr { if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) { discr = new_discr; } } prev_discr = Some(discr); (i, discr) }) } #[inline] pub fn variant_range(&self) -> Range { VariantIdx::new(0)..VariantIdx::new(self.variants.len()) } /// Computes the discriminant value used by a specific variant. /// Unlike `discriminants`, this is (amortized) constant-time, /// only doing at most one query for evaluating an explicit /// discriminant (the last one before the requested variant), /// assuming there are no constant-evaluation errors there. #[inline] pub fn discriminant_for_variant( &self, tcx: TyCtxt<'tcx>, variant_index: VariantIdx, ) -> Discr<'tcx> { assert!(self.is_enum()); let (val, offset) = self.discriminant_def_for_variant(variant_index); let explicit_value = val .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did)) .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx)); explicit_value.checked_add(tcx, offset as u128).0 } /// Yields a `DefId` for the discriminant and an offset to add to it /// Alternatively, if there is no explicit discriminant, returns the /// inferred discriminant directly. pub fn discriminant_def_for_variant(&self, variant_index: VariantIdx) -> (Option, u32) { assert!(!self.variants.is_empty()); let mut explicit_index = variant_index.as_u32(); let expr_did; loop { match self.variants[VariantIdx::from_u32(explicit_index)].discr { ty::VariantDiscr::Relative(0) => { expr_did = None; break; } ty::VariantDiscr::Relative(distance) => { explicit_index -= distance; } ty::VariantDiscr::Explicit(did) => { expr_did = Some(did); break; } } } (expr_did, variant_index.as_u32() - explicit_index) } pub fn destructor(&self, tcx: TyCtxt<'tcx>) -> Option { tcx.adt_destructor(self.did) } /// Returns a list of types such that `Self: Sized` if and only /// if that type is `Sized`, or `TyErr` if this type is recursive. /// /// Oddly enough, checking that the sized-constraint is `Sized` is /// actually more expressive than checking all members: /// the `Sized` trait is inductive, so an associated type that references /// `Self` would prevent its containing ADT from being `Sized`. /// /// Due to normalization being eager, this applies even if /// the associated type is behind a pointer (e.g., issue #31299). pub fn sized_constraint(&self, tcx: TyCtxt<'tcx>) -> &'tcx [Ty<'tcx>] { tcx.adt_sized_constraint(self.did).0 } } impl<'tcx> FieldDef { /// Returns the type of this field. The `subst` is typically obtained /// via the second field of `TyKind::AdtDef`. pub fn ty(&self, tcx: TyCtxt<'tcx>, subst: SubstsRef<'tcx>) -> Ty<'tcx> { tcx.type_of(self.did).subst(tcx, subst) } } /// Represents the various closure traits in the language. This /// will determine the type of the environment (`self`, in the /// desugaring) argument that the closure expects. /// /// You can get the environment type of a closure using /// `tcx.closure_env_ty()`. #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, TyEncodable, TyDecodable)] #[derive(HashStable)] pub enum ClosureKind { // Warning: Ordering is significant here! The ordering is chosen // because the trait Fn is a subtrait of FnMut and so in turn, and // hence we order it so that Fn < FnMut < FnOnce. Fn, FnMut, FnOnce, } impl<'tcx> ClosureKind { // This is the initial value used when doing upvar inference. pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn; pub fn trait_did(&self, tcx: TyCtxt<'tcx>) -> DefId { match *self { ClosureKind::Fn => tcx.require_lang_item(LangItem::Fn, None), ClosureKind::FnMut => tcx.require_lang_item(LangItem::FnMut, None), ClosureKind::FnOnce => tcx.require_lang_item(LangItem::FnOnce, None), } } /// Returns `true` if a type that impls this closure kind /// must also implement `other`. pub fn extends(self, other: ty::ClosureKind) -> bool { matches!( (self, other), (ClosureKind::Fn, ClosureKind::Fn) | (ClosureKind::Fn, ClosureKind::FnMut) | (ClosureKind::Fn, ClosureKind::FnOnce) | (ClosureKind::FnMut, ClosureKind::FnMut) | (ClosureKind::FnMut, ClosureKind::FnOnce) | (ClosureKind::FnOnce, ClosureKind::FnOnce) ) } /// Returns the representative scalar type for this closure kind. /// See `TyS::to_opt_closure_kind` for more details. pub fn to_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> { match self { ty::ClosureKind::Fn => tcx.types.i8, ty::ClosureKind::FnMut => tcx.types.i16, ty::ClosureKind::FnOnce => tcx.types.i32, } } } impl BorrowKind { pub fn from_mutbl(m: hir::Mutability) -> BorrowKind { match m { hir::Mutability::Mut => MutBorrow, hir::Mutability::Not => ImmBorrow, } } /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a /// mutability that is stronger than necessary so that it at least *would permit* the borrow in /// question. pub fn to_mutbl_lossy(self) -> hir::Mutability { match self { MutBorrow => hir::Mutability::Mut, ImmBorrow => hir::Mutability::Not, // We have no type corresponding to a unique imm borrow, so // use `&mut`. It gives all the capabilities of an `&uniq` // and hence is a safe "over approximation". UniqueImmBorrow => hir::Mutability::Mut, } } pub fn to_user_str(&self) -> &'static str { match *self { MutBorrow => "mutable", ImmBorrow => "immutable", UniqueImmBorrow => "uniquely immutable", } } } pub type Attributes<'tcx> = &'tcx [ast::Attribute]; #[derive(Debug, PartialEq, Eq)] pub enum ImplOverlapKind { /// These impls are always allowed to overlap. Permitted { /// Whether or not the impl is permitted due to the trait being a `#[marker]` trait marker: bool, }, /// These impls are allowed to overlap, but that raises /// an issue #33140 future-compatibility warning. /// /// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's /// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different. /// /// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied /// that difference, making what reduces to the following set of impls: /// /// ``` /// trait Trait {} /// impl Trait for dyn Send + Sync {} /// impl Trait for dyn Sync + Send {} /// ``` /// /// Obviously, once we made these types be identical, that code causes a coherence /// error and a fairly big headache for us. However, luckily for us, the trait /// `Trait` used in this case is basically a marker trait, and therefore having /// overlapping impls for it is sound. /// /// To handle this, we basically regard the trait as a marker trait, with an additional /// future-compatibility warning. To avoid accidentally "stabilizing" this feature, /// it has the following restrictions: /// /// 1. The trait must indeed be a marker-like trait (i.e., no items), and must be /// positive impls. /// 2. The trait-ref of both impls must be equal. /// 3. The trait-ref of both impls must be a trait object type consisting only of /// marker traits. /// 4. Neither of the impls can have any where-clauses. /// /// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed. Issue33140, } impl<'tcx> TyCtxt<'tcx> { pub fn typeck_body(self, body: hir::BodyId) -> &'tcx TypeckResults<'tcx> { self.typeck(self.hir().body_owner_def_id(body)) } /// Returns an iterator of the `DefId`s for all body-owners in this /// crate. If you would prefer to iterate over the bodies /// themselves, you can do `self.hir().krate().body_ids.iter()`. pub fn body_owners(self) -> impl Iterator + Captures<'tcx> + 'tcx { self.hir() .krate() .body_ids .iter() .map(move |&body_id| self.hir().body_owner_def_id(body_id)) } pub fn par_body_owners(self, f: F) { par_iter(&self.hir().krate().body_ids) .for_each(|&body_id| f(self.hir().body_owner_def_id(body_id))); } pub fn provided_trait_methods(self, id: DefId) -> impl 'tcx + Iterator { self.associated_items(id) .in_definition_order() .filter(|item| item.kind == AssocKind::Fn && item.defaultness.has_value()) } fn item_name_from_hir(self, def_id: DefId) -> Option { self.hir().get_if_local(def_id).and_then(|node| node.ident()) } fn item_name_from_def_id(self, def_id: DefId) -> Option { if def_id.index == CRATE_DEF_INDEX { Some(self.original_crate_name(def_id.krate)) } else { let def_key = self.def_key(def_id); match def_key.disambiguated_data.data { // The name of a constructor is that of its parent. rustc_hir::definitions::DefPathData::Ctor => self.item_name_from_def_id(DefId { krate: def_id.krate, index: def_key.parent.unwrap(), }), _ => def_key.disambiguated_data.data.get_opt_name(), } } } /// Look up the name of an item across crates. This does not look at HIR. /// /// When possible, this function should be used for cross-crate lookups over /// [`opt_item_name`] to avoid invalidating the incremental cache. If you /// need to handle items without a name, or HIR items that will not be /// serialized cross-crate, or if you need the span of the item, use /// [`opt_item_name`] instead. /// /// [`opt_item_name`]: Self::opt_item_name pub fn item_name(self, id: DefId) -> Symbol { // Look at cross-crate items first to avoid invalidating the incremental cache // unless we have to. self.item_name_from_def_id(id).unwrap_or_else(|| { bug!("item_name: no name for {:?}", self.def_path(id)); }) } /// Look up the name and span of an item or [`Node`]. /// /// See [`item_name`][Self::item_name] for more information. pub fn opt_item_name(self, def_id: DefId) -> Option { // Look at the HIR first so the span will be correct if this is a local item. self.item_name_from_hir(def_id) .or_else(|| self.item_name_from_def_id(def_id).map(Ident::with_dummy_span)) } pub fn opt_associated_item(self, def_id: DefId) -> Option<&'tcx AssocItem> { let is_associated_item = if let Some(def_id) = def_id.as_local() { matches!( self.hir().get(self.hir().local_def_id_to_hir_id(def_id)), Node::TraitItem(_) | Node::ImplItem(_) ) } else { matches!( self.def_kind(def_id), DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy ) }; is_associated_item.then(|| self.associated_item(def_id)) } pub fn field_index(self, hir_id: hir::HirId, typeck_results: &TypeckResults<'_>) -> usize { typeck_results.field_indices().get(hir_id).cloned().expect("no index for a field") } pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option { variant.fields.iter().position(|field| self.hygienic_eq(ident, field.ident, variant.def_id)) } /// Returns `true` if the impls are the same polarity and the trait either /// has no items or is annotated `#[marker]` and prevents item overrides. pub fn impls_are_allowed_to_overlap( self, def_id1: DefId, def_id2: DefId, ) -> Option { // If either trait impl references an error, they're allowed to overlap, // as one of them essentially doesn't exist. if self.impl_trait_ref(def_id1).map_or(false, |tr| tr.references_error()) || self.impl_trait_ref(def_id2).map_or(false, |tr| tr.references_error()) { return Some(ImplOverlapKind::Permitted { marker: false }); } match (self.impl_polarity(def_id1), self.impl_polarity(def_id2)) { (ImplPolarity::Reservation, _) | (_, ImplPolarity::Reservation) => { // `#[rustc_reservation_impl]` impls don't overlap with anything debug!( "impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (reservations)", def_id1, def_id2 ); return Some(ImplOverlapKind::Permitted { marker: false }); } (ImplPolarity::Positive, ImplPolarity::Negative) | (ImplPolarity::Negative, ImplPolarity::Positive) => { // `impl AutoTrait for Type` + `impl !AutoTrait for Type` debug!( "impls_are_allowed_to_overlap({:?}, {:?}) - None (differing polarities)", def_id1, def_id2 ); return None; } (ImplPolarity::Positive, ImplPolarity::Positive) | (ImplPolarity::Negative, ImplPolarity::Negative) => {} }; let is_marker_overlap = { let is_marker_impl = |def_id: DefId| -> bool { let trait_ref = self.impl_trait_ref(def_id); trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker) }; is_marker_impl(def_id1) && is_marker_impl(def_id2) }; if is_marker_overlap { debug!( "impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (marker overlap)", def_id1, def_id2 ); Some(ImplOverlapKind::Permitted { marker: true }) } else { if let Some(self_ty1) = self.issue33140_self_ty(def_id1) { if let Some(self_ty2) = self.issue33140_self_ty(def_id2) { if self_ty1 == self_ty2 { debug!( "impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK", def_id1, def_id2 ); return Some(ImplOverlapKind::Issue33140); } else { debug!( "impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}", def_id1, def_id2, self_ty1, self_ty2 ); } } } debug!("impls_are_allowed_to_overlap({:?}, {:?}) = None", def_id1, def_id2); None } } /// Returns `ty::VariantDef` if `res` refers to a struct, /// or variant or their constructors, panics otherwise. pub fn expect_variant_res(self, res: Res) -> &'tcx VariantDef { match res { Res::Def(DefKind::Variant, did) => { let enum_did = self.parent(did).unwrap(); self.adt_def(enum_did).variant_with_id(did) } Res::Def(DefKind::Struct | DefKind::Union, did) => self.adt_def(did).non_enum_variant(), Res::Def(DefKind::Ctor(CtorOf::Variant, ..), variant_ctor_did) => { let variant_did = self.parent(variant_ctor_did).unwrap(); let enum_did = self.parent(variant_did).unwrap(); self.adt_def(enum_did).variant_with_ctor_id(variant_ctor_did) } Res::Def(DefKind::Ctor(CtorOf::Struct, ..), ctor_did) => { let struct_did = self.parent(ctor_did).expect("struct ctor has no parent"); self.adt_def(struct_did).non_enum_variant() } _ => bug!("expect_variant_res used with unexpected res {:?}", res), } } /// Returns the possibly-auto-generated MIR of a `(DefId, Subst)` pair. pub fn instance_mir(self, instance: ty::InstanceDef<'tcx>) -> &'tcx Body<'tcx> { match instance { ty::InstanceDef::Item(def) => self.optimized_mir_opt_const_arg(def), ty::InstanceDef::VtableShim(..) | ty::InstanceDef::ReifyShim(..) | ty::InstanceDef::Intrinsic(..) | ty::InstanceDef::FnPtrShim(..) | ty::InstanceDef::Virtual(..) | ty::InstanceDef::ClosureOnceShim { .. } | ty::InstanceDef::DropGlue(..) | ty::InstanceDef::CloneShim(..) => self.mir_shims(instance), } } /// Gets the attributes of a definition. pub fn get_attrs(self, did: DefId) -> Attributes<'tcx> { if let Some(did) = did.as_local() { self.hir().attrs(self.hir().local_def_id_to_hir_id(did)) } else { self.item_attrs(did) } } /// Determines whether an item is annotated with an attribute. pub fn has_attr(self, did: DefId, attr: Symbol) -> bool { self.sess.contains_name(&self.get_attrs(did), attr) } /// Returns `true` if this is an `auto trait`. pub fn trait_is_auto(self, trait_def_id: DefId) -> bool { self.trait_def(trait_def_id).has_auto_impl } pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> { self.optimized_mir(def_id).generator_layout.as_ref().unwrap() } /// Given the `DefId` of an impl, returns the `DefId` of the trait it implements. /// If it implements no trait, returns `None`. pub fn trait_id_of_impl(self, def_id: DefId) -> Option { self.impl_trait_ref(def_id).map(|tr| tr.def_id) } /// If the given defid describes a method belonging to an impl, returns the /// `DefId` of the impl that the method belongs to; otherwise, returns `None`. pub fn impl_of_method(self, def_id: DefId) -> Option { self.opt_associated_item(def_id).and_then(|trait_item| match trait_item.container { TraitContainer(_) => None, ImplContainer(def_id) => Some(def_id), }) } /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err` /// with the name of the crate containing the impl. pub fn span_of_impl(self, impl_did: DefId) -> Result { if let Some(impl_did) = impl_did.as_local() { let hir_id = self.hir().local_def_id_to_hir_id(impl_did); Ok(self.hir().span(hir_id)) } else { Err(self.crate_name(impl_did.krate)) } } /// Hygienically compares a use-site name (`use_name`) for a field or an associated item with /// its supposed definition name (`def_name`). The method also needs `DefId` of the supposed /// definition's parent/scope to perform comparison. pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool { // We could use `Ident::eq` here, but we deliberately don't. The name // comparison fails frequently, and we want to avoid the expensive // `normalize_to_macros_2_0()` calls required for the span comparison whenever possible. use_name.name == def_name.name && use_name .span .ctxt() .hygienic_eq(def_name.span.ctxt(), self.expansion_that_defined(def_parent_def_id)) } pub fn expansion_that_defined(self, scope: DefId) -> ExpnId { match scope.as_local() { // Parsing and expansion aren't incremental, so we don't // need to go through a query for the same-crate case. Some(scope) => self.hir().definitions().expansion_that_defined(scope), None => self.expn_that_defined(scope), } } pub fn adjust_ident(self, mut ident: Ident, scope: DefId) -> Ident { ident.span.normalize_to_macros_2_0_and_adjust(self.expansion_that_defined(scope)); ident } pub fn adjust_ident_and_get_scope( self, mut ident: Ident, scope: DefId, block: hir::HirId, ) -> (Ident, DefId) { let scope = match ident.span.normalize_to_macros_2_0_and_adjust(self.expansion_that_defined(scope)) { Some(actual_expansion) => { self.hir().definitions().parent_module_of_macro_def(actual_expansion) } None => self.parent_module(block).to_def_id(), }; (ident, scope) } pub fn is_object_safe(self, key: DefId) -> bool { self.object_safety_violations(key).is_empty() } } #[derive(Clone, HashStable)] pub struct AdtSizedConstraint<'tcx>(pub &'tcx [Ty<'tcx>]); /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition. pub fn is_impl_trait_defn(tcx: TyCtxt<'_>, def_id: DefId) -> Option { if let Some(def_id) = def_id.as_local() { if let Node::Item(item) = tcx.hir().get(tcx.hir().local_def_id_to_hir_id(def_id)) { if let hir::ItemKind::OpaqueTy(ref opaque_ty) = item.kind { return opaque_ty.impl_trait_fn; } } } None } pub fn provide(providers: &mut ty::query::Providers) { context::provide(providers); erase_regions::provide(providers); layout::provide(providers); util::provide(providers); print::provide(providers); super::util::bug::provide(providers); *providers = ty::query::Providers { trait_impls_of: trait_def::trait_impls_of_provider, all_local_trait_impls: trait_def::all_local_trait_impls, ..*providers }; } /// A map for the local crate mapping each type to a vector of its /// inherent impls. This is not meant to be used outside of coherence; /// rather, you should request the vector for a specific type via /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies /// (constructing this map requires touching the entire crate). #[derive(Clone, Debug, Default, HashStable)] pub struct CrateInherentImpls { pub inherent_impls: DefIdMap>, } #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, HashStable)] pub struct SymbolName<'tcx> { /// `&str` gives a consistent ordering, which ensures reproducible builds. pub name: &'tcx str, } impl<'tcx> SymbolName<'tcx> { pub fn new(tcx: TyCtxt<'tcx>, name: &str) -> SymbolName<'tcx> { SymbolName { name: unsafe { str::from_utf8_unchecked(tcx.arena.alloc_slice(name.as_bytes())) }, } } } impl<'tcx> fmt::Display for SymbolName<'tcx> { fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { fmt::Display::fmt(&self.name, fmt) } } impl<'tcx> fmt::Debug for SymbolName<'tcx> { fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { fmt::Display::fmt(&self.name, fmt) } }