| // ignore-tidy-filelength |
| |
| pub use self::Variance::*; |
| pub use self::AssocItemContainer::*; |
| pub use self::BorrowKind::*; |
| pub use self::IntVarValue::*; |
| pub use self::fold::TypeFoldable; |
| |
| use crate::hir::{map as hir_map, GlobMap, TraitMap}; |
| use crate::hir::Node; |
| use crate::hir::def::{Res, DefKind, CtorOf, CtorKind, ExportMap}; |
| use crate::hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE}; |
| use rustc_data_structures::svh::Svh; |
| use rustc_macros::HashStable; |
| use crate::ich::Fingerprint; |
| use crate::ich::StableHashingContext; |
| use crate::infer::canonical::Canonical; |
| use crate::middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem}; |
| use crate::middle::resolve_lifetime::ObjectLifetimeDefault; |
| use crate::mir::Body; |
| use crate::mir::interpret::{GlobalId, ErrorHandled}; |
| use crate::mir::GeneratorLayout; |
| use crate::session::CrateDisambiguator; |
| use crate::traits::{self, Reveal}; |
| use crate::ty; |
| use crate::ty::layout::VariantIdx; |
| use crate::ty::subst::{Subst, InternalSubsts, SubstsRef}; |
| use crate::ty::util::{IntTypeExt, Discr}; |
| use crate::ty::walk::TypeWalker; |
| use crate::util::captures::Captures; |
| use crate::util::nodemap::{NodeSet, DefIdMap, FxHashMap}; |
| use arena::SyncDroplessArena; |
| use crate::session::DataTypeKind; |
| |
| use rustc_serialize::{self, Encodable, Encoder}; |
| use rustc_target::abi::Align; |
| use std::cell::RefCell; |
| use std::cmp::{self, Ordering}; |
| use std::fmt; |
| use std::hash::{Hash, Hasher}; |
| use std::ops::Deref; |
| use rustc_data_structures::sync::{self, Lrc, ParallelIterator, par_iter}; |
| use std::slice; |
| use std::{mem, ptr}; |
| use std::ops::Range; |
| use syntax::ast::{self, Name, Ident, NodeId}; |
| use syntax::attr; |
| use syntax::ext::hygiene::ExpnId; |
| use syntax::symbol::{kw, sym, Symbol, InternedString}; |
| use syntax_pos::Span; |
| |
| use smallvec; |
| use rustc_data_structures::fx::FxIndexMap; |
| use rustc_data_structures::indexed_vec::{Idx, IndexVec}; |
| use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult, |
| HashStable}; |
| |
| use crate::hir; |
| |
| pub use self::sty::{Binder, BoundTy, BoundTyKind, BoundVar, DebruijnIndex, INNERMOST}; |
| pub use self::sty::{FnSig, GenSig, CanonicalPolyFnSig, PolyFnSig, PolyGenSig}; |
| pub use self::sty::{InferTy, ParamTy, ParamConst, InferConst, ProjectionTy, ExistentialPredicate}; |
| pub use self::sty::{ClosureSubsts, GeneratorSubsts, UpvarSubsts, TypeAndMut}; |
| pub use self::sty::{TraitRef, TyKind, PolyTraitRef}; |
| pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef}; |
| pub use self::sty::{ExistentialProjection, PolyExistentialProjection, Const}; |
| pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region}; |
| pub use self::sty::RegionKind; |
| pub use self::sty::{TyVid, IntVid, FloatVid, ConstVid, RegionVid}; |
| pub use self::sty::BoundRegion::*; |
| pub use self::sty::InferTy::*; |
| pub use self::sty::RegionKind::*; |
| pub use self::sty::TyKind::*; |
| |
| pub use self::binding::BindingMode; |
| pub use self::binding::BindingMode::*; |
| |
| pub use self::context::{TyCtxt, FreeRegionInfo, AllArenas, tls, keep_local}; |
| pub use self::context::{Lift, TypeckTables, CtxtInterners, GlobalCtxt}; |
| pub use self::context::{ |
| UserTypeAnnotationIndex, UserType, CanonicalUserType, |
| CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, ResolvedOpaqueTy, |
| }; |
| |
| pub use self::instance::{Instance, InstanceDef}; |
| |
| pub use self::trait_def::TraitDef; |
| |
| pub use self::query::queries; |
| |
| pub mod adjustment; |
| pub mod binding; |
| pub mod cast; |
| #[macro_use] |
| pub mod codec; |
| mod constness; |
| pub mod error; |
| mod erase_regions; |
| pub mod fast_reject; |
| pub mod flags; |
| pub mod fold; |
| pub mod inhabitedness; |
| pub mod layout; |
| pub mod _match; |
| pub mod outlives; |
| pub mod print; |
| pub mod query; |
| pub mod relate; |
| pub mod steal; |
| pub mod subst; |
| pub mod trait_def; |
| pub mod walk; |
| pub mod wf; |
| pub mod util; |
| |
| mod context; |
| mod instance; |
| mod structural_impls; |
| mod sty; |
| |
| // Data types |
| |
| #[derive(Clone)] |
| pub struct Resolutions { |
| pub trait_map: TraitMap, |
| pub maybe_unused_trait_imports: NodeSet, |
| pub maybe_unused_extern_crates: Vec<(NodeId, Span)>, |
| pub export_map: ExportMap<NodeId>, |
| pub glob_map: GlobMap, |
| /// 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<Name, bool>, |
| } |
| |
| #[derive(Clone, Copy, PartialEq, Eq, Debug, HashStable)] |
| 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, PartialEq, Eq, Hash, Debug)] |
| pub struct ImplHeader<'tcx> { |
| pub impl_def_id: DefId, |
| pub self_ty: Ty<'tcx>, |
| pub trait_ref: Option<TraitRef<'tcx>>, |
| pub predicates: Vec<Predicate<'tcx>>, |
| } |
| |
| #[derive(Copy, Clone, Debug, PartialEq, HashStable)] |
| 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 argument, allowing method calls. |
| pub method_has_self_argument: bool, |
| } |
| |
| #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash, RustcEncodable, RustcDecodable, HashStable)] |
| pub enum AssocKind { |
| Const, |
| Method, |
| OpaqueTy, |
| Type |
| } |
| |
| impl AssocItem { |
| pub fn def_kind(&self) -> DefKind { |
| match self.kind { |
| AssocKind::Const => DefKind::AssocConst, |
| AssocKind::Method => DefKind::Method, |
| AssocKind::Type => DefKind::AssocTy, |
| AssocKind::OpaqueTy => DefKind::AssocOpaqueTy, |
| } |
| } |
| |
| /// Tests whether the associated item admits a non-trivial implementation |
| /// for ! |
| pub fn relevant_for_never(&self) -> bool { |
| match self.kind { |
| AssocKind::OpaqueTy | |
| AssocKind::Const | |
| AssocKind::Type => true, |
| // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited. |
| AssocKind::Method => !self.method_has_self_argument, |
| } |
| } |
| |
| pub fn signature(&self, tcx: TyCtxt<'_>) -> String { |
| match self.kind { |
| ty::AssocKind::Method => { |
| // 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), |
| // FIXME(type_alias_impl_trait): we should print bounds here too. |
| ty::AssocKind::OpaqueTy => format!("type {};", self.ident), |
| ty::AssocKind::Const => { |
| format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id)) |
| } |
| } |
| } |
| } |
| |
| #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable, 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<DefId>; |
| |
| 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<DefId> { |
| self.def_key(id).parent.map(|index| DefId { index: 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.hir().get_module_parent(id)) |
| } |
| } |
| } |
| |
| /// Returns `true` if an item with this visibility is accessible from the given block. |
| pub fn is_accessible_from<T: DefIdTree>(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<T: DefIdTree>(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, Eq, RustcDecodable, RustcEncodable, Hash, HashStable)] |
| pub enum Variance { |
| Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type |
| Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell |
| Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type |
| Bivariant, // T<A> <: T<B> -- 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<DefId, &'tcx [ty::Variance]>, |
| } |
| |
| 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<i32> |
| /// |
| /// Here, the "ambient" variance starts as covariant. `*mut T` is |
| /// invariant with respect to `T`, so the variance in which the |
| /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which |
| /// yields `Invariant`. Now, the type `Vec<T>` 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<i32>, *mut Vec<i32) |
| /// |
| /// The ambient variance is covariant. A `fn` type is |
| /// contravariant with respect to its parameters, so the variance |
| /// within which both pointer types appear is |
| /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const |
| /// T` is covariant with respect to `T`, so the variance within |
| /// which the first `Vec<i32>` appears is |
| /// `Contravariant.xform(Covariant)` or `Contravariant`. The same |
| /// is true for its `i32` argument. In the `*mut T` case, the |
| /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`, |
| /// and hence the outermost type is `Invariant` with respect to |
| /// `Vec<i32>` (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, |
| } |
| |
| // 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. |
| bitflags! { |
| pub struct TypeFlags: u32 { |
| const HAS_PARAMS = 1 << 0; |
| const HAS_TY_INFER = 1 << 1; |
| const HAS_RE_INFER = 1 << 2; |
| const HAS_RE_PLACEHOLDER = 1 << 3; |
| |
| /// Does this have any `ReEarlyBound` regions? Used to |
| /// determine whether substitition is required, since those |
| /// represent regions that are bound in a `ty::Generics` and |
| /// hence may be substituted. |
| const HAS_RE_EARLY_BOUND = 1 << 4; |
| |
| /// Does this have any region that "appears free" in the type? |
| /// Basically anything but `ReLateBound` and `ReErased`. |
| const HAS_FREE_REGIONS = 1 << 5; |
| |
| /// Is an error type reachable? |
| const HAS_TY_ERR = 1 << 6; |
| const HAS_PROJECTION = 1 << 7; |
| |
| // FIXME: Rename this to the actual property since it's used for generators too |
| const HAS_TY_CLOSURE = 1 << 8; |
| |
| /// `true` if there are "names" of types and regions and so forth |
| /// that are local to a particular fn |
| const HAS_FREE_LOCAL_NAMES = 1 << 9; |
| |
| /// Present if the type belongs in a local type context. |
| /// Only set for Infer other than Fresh. |
| const KEEP_IN_LOCAL_TCX = 1 << 10; |
| |
| /// Does this have any `ReLateBound` regions? Used to check |
| /// if a global bound is safe to evaluate. |
| const HAS_RE_LATE_BOUND = 1 << 11; |
| |
| const HAS_TY_PLACEHOLDER = 1 << 12; |
| |
| const HAS_CT_INFER = 1 << 13; |
| const HAS_CT_PLACEHOLDER = 1 << 14; |
| |
| const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits | |
| TypeFlags::HAS_RE_EARLY_BOUND.bits; |
| |
| /// Flags representing the nominal content of a type, |
| /// computed by FlagsComputation. If you add a new nominal |
| /// flag, it should be added here too. |
| const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits | |
| TypeFlags::HAS_TY_INFER.bits | |
| TypeFlags::HAS_RE_INFER.bits | |
| TypeFlags::HAS_RE_PLACEHOLDER.bits | |
| TypeFlags::HAS_RE_EARLY_BOUND.bits | |
| TypeFlags::HAS_FREE_REGIONS.bits | |
| TypeFlags::HAS_TY_ERR.bits | |
| TypeFlags::HAS_PROJECTION.bits | |
| TypeFlags::HAS_TY_CLOSURE.bits | |
| TypeFlags::HAS_FREE_LOCAL_NAMES.bits | |
| TypeFlags::KEEP_IN_LOCAL_TCX.bits | |
| TypeFlags::HAS_RE_LATE_BOUND.bits | |
| TypeFlags::HAS_TY_PLACEHOLDER.bits | |
| TypeFlags::HAS_CT_INFER.bits | |
| TypeFlags::HAS_CT_PLACEHOLDER.bits; |
| } |
| } |
| |
| #[allow(rustc::usage_of_ty_tykind)] |
| pub struct TyS<'tcx> { |
| pub sty: TyKind<'tcx>, |
| pub 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, |
| } |
| |
| // `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.sty.cmp(&other.sty) |
| } |
| } |
| |
| impl<'tcx> PartialOrd for TyS<'tcx> { |
| fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> { |
| Some(self.sty.cmp(&other.sty)) |
| } |
| } |
| |
| 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<H: Hasher>(&self, s: &mut H) { |
| (self as *const TyS<'_>).hash(s) |
| } |
| } |
| |
| impl<'tcx> TyS<'tcx> { |
| pub fn is_primitive_ty(&self) -> bool { |
| match self.sty { |
| Bool | |
| Char | |
| Int(_) | |
| Uint(_) | |
| Float(_) | |
| Infer(InferTy::IntVar(_)) | |
| Infer(InferTy::FloatVar(_)) | |
| Infer(InferTy::FreshIntTy(_)) | |
| Infer(InferTy::FreshFloatTy(_)) => true, |
| Ref(_, x, _) => x.is_primitive_ty(), |
| _ => false, |
| } |
| } |
| |
| pub fn is_suggestable(&self) -> bool { |
| match self.sty { |
| Opaque(..) | |
| FnDef(..) | |
| FnPtr(..) | |
| Dynamic(..) | |
| Closure(..) | |
| Infer(..) | |
| Projection(..) => false, |
| _ => true, |
| } |
| } |
| } |
| |
| impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ty::TyS<'tcx> { |
| fn hash_stable<W: StableHasherResult>(&self, |
| hcx: &mut StableHashingContext<'a>, |
| hasher: &mut StableHasher<W>) { |
| let ty::TyS { |
| ref sty, |
| |
| // The other fields just provide fast access to information that is |
| // also contained in `sty`, so no need to hash them. |
| flags: _, |
| |
| outer_exclusive_binder: _, |
| } = *self; |
| |
| sty.hash_stable(hcx, hasher); |
| } |
| } |
| |
| #[cfg_attr(not(bootstrap), rustc_diagnostic_item = "Ty")] |
| pub type Ty<'tcx> = &'tcx TyS<'tcx>; |
| |
| impl<'tcx> rustc_serialize::UseSpecializedEncodable for Ty<'tcx> {} |
| impl<'tcx> rustc_serialize::UseSpecializedDecodable for Ty<'tcx> {} |
| |
| pub type CanonicalTy<'tcx> = Canonical<'tcx, Ty<'tcx>>; |
| |
| extern { |
| /// A dummy type used to force `List` to by unsized without requiring fat pointers. |
| type OpaqueListContents; |
| } |
| |
| /// A wrapper for slices with the additional invariant |
| /// that the slice is interned and no other slice with |
| /// the same contents can exist in the same context. |
| /// This means we can use pointer for both |
| /// equality comparisons and hashing. |
| /// Note: `Slice` was already taken by the `Ty`. |
| #[repr(C)] |
| pub struct List<T> { |
| len: usize, |
| data: [T; 0], |
| opaque: OpaqueListContents, |
| } |
| |
| unsafe impl<T: Sync> Sync for List<T> {} |
| |
| impl<T: Copy> List<T> { |
| #[inline] |
| fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx List<T> { |
| assert!(!mem::needs_drop::<T>()); |
| assert!(mem::size_of::<T>() != 0); |
| assert!(slice.len() != 0); |
| |
| // Align up the size of the len (usize) field |
| let align = mem::align_of::<T>(); |
| let align_mask = align - 1; |
| let offset = mem::size_of::<usize>(); |
| let offset = (offset + align_mask) & !align_mask; |
| |
| let size = offset + slice.len() * mem::size_of::<T>(); |
| |
| let mem = arena.alloc_raw( |
| size, |
| cmp::max(mem::align_of::<T>(), mem::align_of::<usize>())); |
| unsafe { |
| let result = &mut *(mem.as_mut_ptr() as *mut List<T>); |
| // Write the length |
| result.len = slice.len(); |
| |
| // Write the elements |
| let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len); |
| arena_slice.copy_from_slice(slice); |
| |
| result |
| } |
| } |
| } |
| |
| impl<T: fmt::Debug> fmt::Debug for List<T> { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| (**self).fmt(f) |
| } |
| } |
| |
| impl<T: Encodable> Encodable for List<T> { |
| #[inline] |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| (**self).encode(s) |
| } |
| } |
| |
| impl<T> Ord for List<T> where T: Ord { |
| fn cmp(&self, other: &List<T>) -> Ordering { |
| if self == other { Ordering::Equal } else { |
| <[T] as Ord>::cmp(&**self, &**other) |
| } |
| } |
| } |
| |
| impl<T> PartialOrd for List<T> where T: PartialOrd { |
| fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> { |
| if self == other { Some(Ordering::Equal) } else { |
| <[T] as PartialOrd>::partial_cmp(&**self, &**other) |
| } |
| } |
| } |
| |
| impl<T: PartialEq> PartialEq for List<T> { |
| #[inline] |
| fn eq(&self, other: &List<T>) -> bool { |
| ptr::eq(self, other) |
| } |
| } |
| impl<T: Eq> Eq for List<T> {} |
| |
| impl<T> Hash for List<T> { |
| #[inline] |
| fn hash<H: Hasher>(&self, s: &mut H) { |
| (self as *const List<T>).hash(s) |
| } |
| } |
| |
| impl<T> Deref for List<T> { |
| type Target = [T]; |
| #[inline(always)] |
| fn deref(&self) -> &[T] { |
| unsafe { |
| slice::from_raw_parts(self.data.as_ptr(), self.len) |
| } |
| } |
| } |
| |
| impl<'a, T> IntoIterator for &'a List<T> { |
| type Item = &'a T; |
| type IntoIter = <&'a [T] as IntoIterator>::IntoIter; |
| #[inline(always)] |
| fn into_iter(self) -> Self::IntoIter { |
| self[..].iter() |
| } |
| } |
| |
| impl<'tcx> rustc_serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {} |
| |
| impl<T> List<T> { |
| #[inline(always)] |
| pub fn empty<'a>() -> &'a List<T> { |
| #[repr(align(64), C)] |
| struct EmptySlice([u8; 64]); |
| static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]); |
| assert!(mem::align_of::<T>() <= 64); |
| unsafe { |
| &*(&EMPTY_SLICE as *const _ as *const List<T>) |
| } |
| } |
| } |
| |
| #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, 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, RustcEncodable, RustcDecodable, HashStable)] |
| pub struct UpvarId { |
| pub var_path: UpvarPath, |
| pub closure_expr_id: LocalDefId, |
| } |
| |
| #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, 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, RustcEncodable, RustcDecodable, 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. |
| ByValue, |
| |
| /// Upvar is captured by reference. |
| ByRef(UpvarBorrow<'tcx>), |
| } |
| |
| #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable, 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>, |
| } |
| |
| pub type UpvarListMap = FxHashMap<DefId, FxIndexMap<hir::HirId, UpvarId>>; |
| pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>; |
| |
| #[derive(Copy, Clone)] |
| pub struct ClosureUpvar<'tcx> { |
| pub res: Res, |
| pub span: Span, |
| pub ty: Ty<'tcx>, |
| } |
| |
| #[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 { |
| pub fn to_bound_region(&self) -> ty::BoundRegion { |
| ty::BoundRegion::BrNamed(self.def_id, self.name) |
| } |
| |
| /// 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.as_interned_str() |
| } |
| } |
| |
| #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)] |
| pub enum GenericParamDefKind { |
| Lifetime, |
| Type { |
| has_default: bool, |
| object_lifetime_default: ObjectLifetimeDefault, |
| synthetic: Option<hir::SyntheticTyParamKind>, |
| }, |
| Const, |
| } |
| |
| #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)] |
| pub struct GenericParamDef { |
| pub name: InternedString, |
| 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") |
| } |
| } |
| |
| pub fn to_bound_region(&self) -> ty::BoundRegion { |
| if let GenericParamDefKind::Lifetime = self.kind { |
| self.to_early_bound_region_data().to_bound_region() |
| } 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, RustcEncodable, RustcDecodable, HashStable)] |
| pub struct Generics { |
| pub parent: Option<DefId>, |
| pub parent_count: usize, |
| pub params: Vec<GenericParamDef>, |
| |
| /// Reverse map to the `index` field of each `GenericParamDef`. |
| #[stable_hasher(ignore)] |
| pub param_def_id_to_index: FxHashMap<DefId, u32>, |
| |
| pub has_self: bool, |
| pub has_late_bound_regions: Option<Span>, |
| } |
| |
| 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 |
| } |
| |
| pub fn region_param( |
| &'tcx self, |
| param: &EarlyBoundRegion, |
| tcx: TyCtxt<'tcx>, |
| ) -> &'tcx GenericParamDef { |
| if let Some(index) = param.index.checked_sub(self.parent_count as u32) { |
| let param = &self.params[index as usize]; |
| match param.kind { |
| GenericParamDefKind::Lifetime => param, |
| _ => bug!("expected lifetime parameter, but found another generic parameter") |
| } |
| } else { |
| tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?")) |
| .region_param(param, tcx) |
| } |
| } |
| |
| /// Returns the `GenericParamDef` associated with this `ParamTy`. |
| pub fn type_param(&'tcx self, param: &ParamTy, tcx: TyCtxt<'tcx>) -> &'tcx GenericParamDef { |
| if let Some(index) = param.index.checked_sub(self.parent_count as u32) { |
| let param = &self.params[index as usize]; |
| match param.kind { |
| GenericParamDefKind::Type { .. } => param, |
| _ => bug!("expected type parameter, but found another generic parameter") |
| } |
| } else { |
| tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?")) |
| .type_param(param, tcx) |
| } |
| } |
| |
| /// Returns the `ConstParameterDef` associated with this `ParamConst`. |
| pub fn const_param(&'tcx self, param: &ParamConst, tcx: TyCtxt<'tcx>) -> &GenericParamDef { |
| if let Some(index) = param.index.checked_sub(self.parent_count as u32) { |
| let param = &self.params[index as usize]; |
| match param.kind { |
| GenericParamDefKind::Const => param, |
| _ => bug!("expected const parameter, but found another generic parameter") |
| } |
| } else { |
| tcx.generics_of(self.parent.expect("parent_count>0 but no parent?")) |
| .const_param(param, tcx) |
| } |
| } |
| } |
| |
| /// Bounds on generics. |
| #[derive(Clone, Default, Debug, HashStable)] |
| pub struct GenericPredicates<'tcx> { |
| pub parent: Option<DefId>, |
| pub predicates: Vec<(Predicate<'tcx>, Span)>, |
| } |
| |
| impl<'tcx> rustc_serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {} |
| impl<'tcx> rustc_serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {} |
| |
| 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(), |
| } |
| } |
| |
| 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)), |
| ); |
| } |
| |
| 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)) |
| } |
| |
| pub fn instantiate_supertrait( |
| &self, |
| tcx: TyCtxt<'tcx>, |
| poly_trait_ref: &ty::PolyTraitRef<'tcx>, |
| ) -> InstantiatedPredicates<'tcx> { |
| assert_eq!(self.parent, None); |
| InstantiatedPredicates { |
| predicates: self.predicates.iter().map(|(pred, _)| { |
| pred.subst_supertrait(tcx, poly_trait_ref) |
| }).collect() |
| } |
| } |
| } |
| |
| #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)] |
| pub enum Predicate<'tcx> { |
| /// Corresponds to `where Foo: Bar<A, B, C>`. `Foo` here would be |
| /// the `Self` type of the trait reference and `A`, `B`, and `C` |
| /// would be the type parameters. |
| Trait(PolyTraitPredicate<'tcx>), |
| |
| /// `where 'a: 'b` |
| RegionOutlives(PolyRegionOutlivesPredicate<'tcx>), |
| |
| /// `where T: 'a` |
| TypeOutlives(PolyTypeOutlivesPredicate<'tcx>), |
| |
| /// `where <T as TraitRef>::Name == X`, approximately. |
| /// See the `ProjectionPredicate` struct for details. |
| Projection(PolyProjectionPredicate<'tcx>), |
| |
| /// No syntax: `T` well-formed. |
| WellFormed(Ty<'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, ClosureSubsts<'tcx>, ClosureKind), |
| |
| /// `T1 <: T2` |
| Subtype(PolySubtypePredicate<'tcx>), |
| |
| /// Constant initializer must evaluate successfully. |
| ConstEvaluatable(DefId, SubstsRef<'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<DefId, &'tcx [ty::Predicate<'tcx>]>, |
| } |
| |
| impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> { |
| fn as_ref(&self) -> &Predicate<'tcx> { |
| self |
| } |
| } |
| |
| 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>, |
| ) -> ty::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; |
| match *self { |
| Predicate::Trait(ref binder) => |
| Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))), |
| Predicate::Subtype(ref binder) => |
| Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))), |
| Predicate::RegionOutlives(ref binder) => |
| Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))), |
| Predicate::TypeOutlives(ref binder) => |
| Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))), |
| Predicate::Projection(ref binder) => |
| Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))), |
| Predicate::WellFormed(data) => |
| Predicate::WellFormed(data.subst(tcx, substs)), |
| Predicate::ObjectSafe(trait_def_id) => |
| Predicate::ObjectSafe(trait_def_id), |
| Predicate::ClosureKind(closure_def_id, closure_substs, kind) => |
| Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind), |
| Predicate::ConstEvaluatable(def_id, const_substs) => |
| Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)), |
| } |
| } |
| } |
| |
| #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)] |
| pub struct TraitPredicate<'tcx> { |
| pub trait_ref: TraitRef<'tcx> |
| } |
| |
| pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>; |
| |
| impl<'tcx> TraitPredicate<'tcx> { |
| pub fn def_id(&self) -> DefId { |
| self.trait_ref.def_id |
| } |
| |
| pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item = Ty<'tcx>> + 'a { |
| self.trait_ref.input_types() |
| } |
| |
| 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, RustcEncodable, RustcDecodable, HashStable)] |
| pub struct OutlivesPredicate<A, B>(pub A, pub B); // `A: B` |
| pub type PolyOutlivesPredicate<A, B> = ty::Binder<OutlivesPredicate<A, B>>; |
| pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>; |
| pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>; |
| pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>; |
| pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>; |
| |
| #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, HashStable)] |
| pub struct SubtypePredicate<'tcx> { |
| pub a_is_expected: bool, |
| pub a: Ty<'tcx>, |
| pub b: Ty<'tcx> |
| } |
| pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>; |
| |
| /// 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. `<T as TraitRef<...>>::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, RustcEncodable, RustcDecodable, HashStable)] |
| pub struct ProjectionPredicate<'tcx> { |
| pub projection_ty: ProjectionTy<'tcx>, |
| pub ty: Ty<'tcx>, |
| } |
| |
| pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>; |
| |
| 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<'_>) -> 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<Ty<'tcx>> { |
| 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.clone()) |
| } |
| } |
| |
| 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) -> Predicate<'tcx>; |
| } |
| |
| impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> { |
| fn to_predicate(&self) -> Predicate<'tcx> { |
| ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate { |
| trait_ref: self.clone() |
| })) |
| } |
| } |
| |
| impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> { |
| fn to_predicate(&self) -> Predicate<'tcx> { |
| ty::Predicate::Trait(self.to_poly_trait_predicate()) |
| } |
| } |
| |
| impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> { |
| fn to_predicate(&self) -> Predicate<'tcx> { |
| Predicate::RegionOutlives(self.clone()) |
| } |
| } |
| |
| impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> { |
| fn to_predicate(&self) -> Predicate<'tcx> { |
| Predicate::TypeOutlives(self.clone()) |
| } |
| } |
| |
| impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> { |
| fn to_predicate(&self) -> Predicate<'tcx> { |
| Predicate::Projection(self.clone()) |
| } |
| } |
| |
| // A custom iterator used by `Predicate::walk_tys`. |
| enum WalkTysIter<'tcx, I, J, K> |
| where I: Iterator<Item = Ty<'tcx>>, |
| J: Iterator<Item = Ty<'tcx>>, |
| K: Iterator<Item = Ty<'tcx>> |
| { |
| None, |
| One(Ty<'tcx>), |
| Two(Ty<'tcx>, Ty<'tcx>), |
| Types(I), |
| InputTypes(J), |
| ProjectionTypes(K) |
| } |
| |
| impl<'tcx, I, J, K> Iterator for WalkTysIter<'tcx, I, J, K> |
| where I: Iterator<Item = Ty<'tcx>>, |
| J: Iterator<Item = Ty<'tcx>>, |
| K: Iterator<Item = Ty<'tcx>> |
| { |
| type Item = Ty<'tcx>; |
| |
| fn next(&mut self) -> Option<Ty<'tcx>> { |
| match *self { |
| WalkTysIter::None => None, |
| WalkTysIter::One(item) => { |
| *self = WalkTysIter::None; |
| Some(item) |
| }, |
| WalkTysIter::Two(item1, item2) => { |
| *self = WalkTysIter::One(item2); |
| Some(item1) |
| }, |
| WalkTysIter::Types(ref mut iter) => { |
| iter.next() |
| }, |
| WalkTysIter::InputTypes(ref mut iter) => { |
| iter.next() |
| }, |
| WalkTysIter::ProjectionTypes(ref mut iter) => { |
| iter.next() |
| } |
| } |
| } |
| } |
| |
| impl<'tcx> Predicate<'tcx> { |
| /// Iterates over the types in this predicate. Note that in all |
| /// cases this is skipping over a binder, so late-bound regions |
| /// with depth 0 are bound by the predicate. |
| pub fn walk_tys(&'a self) -> impl Iterator<Item = Ty<'tcx>> + 'a { |
| match *self { |
| ty::Predicate::Trait(ref data) => { |
| WalkTysIter::InputTypes(data.skip_binder().input_types()) |
| } |
| ty::Predicate::Subtype(binder) => { |
| let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder(); |
| WalkTysIter::Two(a, b) |
| } |
| ty::Predicate::TypeOutlives(binder) => { |
| WalkTysIter::One(binder.skip_binder().0) |
| } |
| ty::Predicate::RegionOutlives(..) => { |
| WalkTysIter::None |
| } |
| ty::Predicate::Projection(ref data) => { |
| let inner = data.skip_binder(); |
| WalkTysIter::ProjectionTypes( |
| inner.projection_ty.substs.types().chain(Some(inner.ty))) |
| } |
| ty::Predicate::WellFormed(data) => { |
| WalkTysIter::One(data) |
| } |
| ty::Predicate::ObjectSafe(_trait_def_id) => { |
| WalkTysIter::None |
| } |
| ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => { |
| WalkTysIter::Types(closure_substs.substs.types()) |
| } |
| ty::Predicate::ConstEvaluatable(_, substs) => { |
| WalkTysIter::Types(substs.types()) |
| } |
| } |
| } |
| |
| pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> { |
| match *self { |
| Predicate::Trait(ref t) => { |
| Some(t.to_poly_trait_ref()) |
| } |
| Predicate::Projection(..) | |
| Predicate::Subtype(..) | |
| Predicate::RegionOutlives(..) | |
| Predicate::WellFormed(..) | |
| Predicate::ObjectSafe(..) | |
| Predicate::ClosureKind(..) | |
| Predicate::TypeOutlives(..) | |
| Predicate::ConstEvaluatable(..) => { |
| None |
| } |
| } |
| } |
| |
| pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> { |
| match *self { |
| Predicate::TypeOutlives(data) => { |
| Some(data) |
| } |
| Predicate::Trait(..) | |
| Predicate::Projection(..) | |
| Predicate::Subtype(..) | |
| Predicate::RegionOutlives(..) | |
| Predicate::WellFormed(..) | |
| Predicate::ObjectSafe(..) | |
| Predicate::ClosureKind(..) | |
| Predicate::ConstEvaluatable(..) => { |
| 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<T, U: Bar<T>> { ... } |
| /// |
| /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like |
| /// `[[], [U:Bar<T>]]`. Now if there were some particular reference |
| /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[], |
| /// [usize:Bar<isize>]]`. |
| #[derive(Clone, Debug)] |
| pub struct InstantiatedPredicates<'tcx> { |
| pub predicates: Vec<Predicate<'tcx>>, |
| } |
| |
| impl<'tcx> InstantiatedPredicates<'tcx> { |
| pub fn empty() -> InstantiatedPredicates<'tcx> { |
| InstantiatedPredicates { predicates: vec![] } |
| } |
| |
| pub fn is_empty(&self) -> bool { |
| self.predicates.is_empty() |
| } |
| } |
| |
| 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<T>(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 { |
| DEBUG_FORMAT = "U{}", |
| } |
| } |
| |
| impl_stable_hash_for!(struct UniverseIndex { private }); |
| |
| impl UniverseIndex { |
| pub const ROOT: UniverseIndex = UniverseIndex::from_u32_const(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. |
| /// Placeholder regions are identified by both a **universe** as well |
| /// as a "bound-region" within that universe. The `bound_region` is |
| /// basically a name -- distinct bound regions within the same |
| /// universe are just two regions with an unknown relationship to one |
| /// another. |
| #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)] |
| pub struct Placeholder<T> { |
| pub universe: UniverseIndex, |
| pub name: T, |
| } |
| |
| impl<'a, T> HashStable<StableHashingContext<'a>> for Placeholder<T> |
| where |
| T: HashStable<StableHashingContext<'a>>, |
| { |
| fn hash_stable<W: StableHasherResult>( |
| &self, |
| hcx: &mut StableHashingContext<'a>, |
| hasher: &mut StableHasher<W> |
| ) { |
| self.universe.hash_stable(hcx, hasher); |
| self.name.hash_stable(hcx, hasher); |
| } |
| } |
| |
| pub type PlaceholderRegion = Placeholder<BoundRegion>; |
| |
| pub type PlaceholderType = Placeholder<BoundVar>; |
| |
| pub type PlaceholderConst = Placeholder<BoundVar>; |
| |
| /// 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, Debug, PartialEq, Eq, Hash, HashStable)] |
| pub struct ParamEnv<'tcx> { |
| /// `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. |
| pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>, |
| |
| /// Typically, this is `Reveal::UserFacing`, but during codegen we |
| /// want `Reveal::All` -- note that this is always paired with an |
| /// empty environment. To get that, use `ParamEnv::reveal()`. |
| pub reveal: traits::Reveal, |
| |
| /// If this `ParamEnv` comes from a call to `tcx.param_env(def_id)`, |
| /// register that `def_id` (useful for transitioning to the chalk trait |
| /// solver). |
| pub def_id: Option<DefId>, |
| } |
| |
| 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, None) |
| } |
| |
| /// 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, None) |
| } |
| |
| /// Construct a trait environment with the given set of predicates. |
| #[inline] |
| pub fn new( |
| caller_bounds: &'tcx List<ty::Predicate<'tcx>>, |
| reveal: Reveal, |
| def_id: Option<DefId> |
| ) -> Self { |
| ty::ParamEnv { caller_bounds, reveal, def_id } |
| } |
| |
| /// 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. |
| pub fn with_reveal_all(self) -> Self { |
| ty::ParamEnv { reveal: Reveal::All, ..self } |
| } |
| |
| /// Returns this same environment but with no caller bounds. |
| pub fn without_caller_bounds(self) -> Self { |
| ty::ParamEnv { caller_bounds: List::empty(), ..self } |
| } |
| |
| /// 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<u32>: 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<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> { |
| match self.reveal { |
| Reveal::UserFacing => { |
| ParamEnvAnd { |
| param_env: self, |
| value, |
| } |
| } |
| |
| Reveal::All => { |
| if value.has_placeholders() |
| || value.needs_infer() |
| || value.has_param_types() |
| { |
| ParamEnvAnd { |
| param_env: self, |
| value, |
| } |
| } else { |
| ParamEnvAnd { |
| param_env: self.without_caller_bounds(), |
| value, |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)] |
| 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<StableHashingContext<'a>> for ParamEnvAnd<'tcx, T> |
| where |
| T: HashStable<StableHashingContext<'a>>, |
| { |
| fn hash_stable<W: StableHasherResult>(&self, |
| hcx: &mut StableHashingContext<'a>, |
| hasher: &mut StableHasher<W>) { |
| 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 a `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 a `Box`. |
| const IS_BOX = 1 << 6; |
| /// Indicates whether the type is an `Arc`. |
| const IS_ARC = 1 << 7; |
| /// Indicates whether the type is an `Rc`. |
| const IS_RC = 1 << 8; |
| /// 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 << 9; |
| } |
| } |
| |
| 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; |
| } |
| } |
| |
| /// Definition of a variant -- a struct's fields or a enum variant. |
| #[derive(Debug)] |
| 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<DefId>, |
| /// Variant or struct name. |
| pub ident: Ident, |
| /// Discriminant of this variant. |
| pub discr: VariantDiscr, |
| /// Fields of this variant. |
| pub fields: Vec<FieldDef>, |
| /// Type of constructor of variant. |
| pub ctor_kind: CtorKind, |
| /// Flags of the variant (e.g. is field list non-exhaustive)? |
| flags: VariantFlags, |
| /// Variant is obtained as part of recovering from a syntactic error. |
| /// May be incomplete or bogus. |
| pub recovered: bool, |
| } |
| |
| impl<'tcx> 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( |
| tcx: TyCtxt<'tcx>, |
| ident: Ident, |
| variant_did: Option<DefId>, |
| ctor_def_id: Option<DefId>, |
| discr: VariantDiscr, |
| fields: Vec<FieldDef>, |
| ctor_kind: CtorKind, |
| adt_kind: AdtKind, |
| parent_did: DefId, |
| recovered: 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 adt_kind == AdtKind::Struct && tcx.has_attr(parent_did, sym::non_exhaustive) { |
| debug!("found non-exhaustive field list for {:?}", parent_did); |
| flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE; |
| } else if let Some(variant_did) = variant_did { |
| if tcx.has_attr(variant_did, sym::non_exhaustive) { |
| debug!("found non-exhaustive field list for {:?}", variant_did); |
| flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE; |
| } |
| } |
| |
| VariantDef { |
| def_id: variant_did.unwrap_or(parent_did), |
| ctor_def_id, |
| ident, |
| discr, |
| fields, |
| ctor_kind, |
| flags, |
| recovered, |
| } |
| } |
| |
| /// 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) |
| } |
| } |
| |
| impl_stable_hash_for!(struct VariantDef { |
| def_id, |
| ctor_def_id, |
| ident -> (ident.name), |
| discr, |
| fields, |
| ctor_kind, |
| flags, |
| recovered |
| }); |
| |
| #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, 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 an abstract data type -- a struct or enum. |
| /// |
| /// These are all interned (by `intern_adt_def`) into the `adt_defs` table. |
| pub struct AdtDef { |
| /// `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<self::layout::VariantIdx, VariantDef>, |
| /// 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<Ordering> { |
| 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 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<H: Hasher>(&self, s: &mut H) { |
| (self as *const AdtDef).hash(s) |
| } |
| } |
| |
| impl<'tcx> rustc_serialize::UseSpecializedEncodable for &'tcx AdtDef { |
| fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| self.did.encode(s) |
| } |
| } |
| |
| impl<'tcx> rustc_serialize::UseSpecializedDecodable for &'tcx AdtDef {} |
| |
| |
| impl<'a> HashStable<StableHashingContext<'a>> for AdtDef { |
| fn hash_stable<W: StableHasherResult>(&self, |
| hcx: &mut StableHashingContext<'a>, |
| hasher: &mut StableHasher<W>) { |
| thread_local! { |
| static CACHE: RefCell<FxHashMap<usize, Fingerprint>> = 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<DataTypeKind> for AdtKind { |
| fn into(self) -> DataTypeKind { |
| match self { |
| AdtKind::Struct => DataTypeKind::Struct, |
| AdtKind::Union => DataTypeKind::Union, |
| AdtKind::Enum => DataTypeKind::Enum, |
| } |
| } |
| } |
| |
| bitflags! { |
| #[derive(RustcEncodable, RustcDecodable, Default)] |
| 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; |
| |
| // 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; |
| } |
| } |
| |
| impl_stable_hash_for!(struct ReprFlags { |
| bits |
| }); |
| |
| /// Represents the repr options provided by the user, |
| #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)] |
| pub struct ReprOptions { |
| pub int: Option<attr::IntType>, |
| pub align: Option<Align>, |
| pub pack: Option<Align>, |
| pub flags: ReprFlags, |
| } |
| |
| impl_stable_hash_for!(struct ReprOptions { |
| align, |
| pack, |
| int, |
| flags |
| }); |
| |
| impl ReprOptions { |
| pub fn new(tcx: TyCtxt<'_>, did: DefId) -> ReprOptions { |
| let mut flags = ReprFlags::empty(); |
| let mut size = None; |
| let mut max_align: Option<Align> = None; |
| let mut min_pack: Option<Align> = None; |
| for attr in tcx.get_attrs(did).iter() { |
| for r in attr::find_repr_attrs(&tcx.sess.parse_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::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: 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) } |
| |
| 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(<int>)`. |
| 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<VariantIdx, VariantDef>, |
| 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 attr::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().arc() { |
| flags |= AdtFlags::IS_ARC; |
| } |
| if Some(did) == tcx.lang_items().rc() { |
| flags |= AdtFlags::IS_RC; |
| } |
| |
| 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<T>`. |
| #[inline] |
| pub fn is_phantom_data(&self) -> bool { |
| self.flags.contains(AdtFlags::IS_PHANTOM_DATA) |
| } |
| |
| /// Returns `true` if this is `Arc<T>`. |
| pub fn is_arc(&self) -> bool { |
| self.flags.contains(AdtFlags::IS_ARC) |
| } |
| |
| /// Returns `true` if this is `Rc<T>`. |
| pub fn is_rc(&self) -> bool { |
| self.flags.contains(AdtFlags::IS_RC) |
| } |
| |
| /// Returns `true` if this is Box<T>. |
| #[inline] |
| pub fn is_box(&self) -> bool { |
| self.flags.contains(AdtFlags::IS_BOX) |
| } |
| |
| /// 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>) -> &'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<Item=&FieldDef> + Clone { |
| self.variants.iter().flat_map(|v| v.fields.iter()) |
| } |
| |
| pub fn is_payloadfree(&self) -> bool { |
| !self.variants.is_empty() && |
| 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<Discr<'tcx>> { |
| let param_env = tcx.param_env(expr_did); |
| let repr_type = self.repr.discr_type(); |
| let substs = InternalSubsts::identity_for_item(tcx.global_tcx(), expr_did); |
| let instance = ty::Instance::new(expr_did, substs); |
| let cid = GlobalId { |
| instance, |
| promoted: None |
| }; |
| match tcx.const_eval(param_env.and(cid)) { |
| Ok(val) => { |
| // FIXME: Find the right type and use it instead of `val.ty` here |
| if let Some(b) = val.try_eval_bits(tcx.global_tcx(), param_env, val.ty) { |
| trace!("discriminants: {} ({:?})", b, repr_type); |
| Some(Discr { |
| val: b, |
| ty: val.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(ErrorHandled::Reported) => { |
| if !expr_did.is_local() { |
| span_bug!(tcx.def_span(expr_did), |
| "variant discriminant evaluation succeeded \ |
| in its crate but failed locally"); |
| } |
| None |
| } |
| Err(ErrorHandled::TooGeneric) => span_bug!( |
| tcx.def_span(expr_did), |
| "enum discriminant depends on generic arguments", |
| ), |
| } |
| } |
| |
| #[inline] |
| pub fn discriminants( |
| &'tcx self, |
| tcx: TyCtxt<'tcx>, |
| ) -> impl Iterator<Item = (VariantIdx, Discr<'tcx>)> + Captures<'tcx> { |
| let repr_type = self.repr.discr_type(); |
| let initial = repr_type.initial_discriminant(tcx.global_tcx()); |
| let mut prev_discr = None::<Discr<'tcx>>; |
| 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> { |
| (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> { |
| 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.global_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<DefId>, u32) { |
| 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<Destructor> { |
| 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 |
| } |
| |
| fn sized_constraint_for_ty(&self, tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Vec<Ty<'tcx>> { |
| let result = match ty.sty { |
| Bool | Char | Int(..) | Uint(..) | Float(..) | |
| RawPtr(..) | Ref(..) | FnDef(..) | FnPtr(_) | |
| Array(..) | Closure(..) | Generator(..) | Never => { |
| vec![] |
| } |
| |
| Str | |
| Dynamic(..) | |
| Slice(_) | |
| Foreign(..) | |
| Error | |
| GeneratorWitness(..) => { |
| // these are never sized - return the target type |
| vec![ty] |
| } |
| |
| Tuple(ref tys) => { |
| match tys.last() { |
| None => vec![], |
| Some(ty) => self.sized_constraint_for_ty(tcx, ty.expect_ty()), |
| } |
| } |
| |
| Adt(adt, substs) => { |
| // recursive case |
| let adt_tys = adt.sized_constraint(tcx); |
| debug!("sized_constraint_for_ty({:?}) intermediate = {:?}", |
| ty, adt_tys); |
| adt_tys.iter() |
| .map(|ty| ty.subst(tcx, substs)) |
| .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty)) |
| .collect() |
| } |
| |
| Projection(..) | Opaque(..) => { |
| // must calculate explicitly. |
| // FIXME: consider special-casing always-Sized projections |
| vec![ty] |
| } |
| |
| UnnormalizedProjection(..) => bug!("only used with chalk-engine"), |
| |
| Param(..) => { |
| // perf hack: if there is a `T: Sized` bound, then |
| // we know that `T` is Sized and do not need to check |
| // it on the impl. |
| |
| let sized_trait = match tcx.lang_items().sized_trait() { |
| Some(x) => x, |
| _ => return vec![ty] |
| }; |
| let sized_predicate = Binder::dummy(TraitRef { |
| def_id: sized_trait, |
| substs: tcx.mk_substs_trait(ty, &[]) |
| }).to_predicate(); |
| let predicates = &tcx.predicates_of(self.did).predicates; |
| if predicates.iter().any(|(p, _)| *p == sized_predicate) { |
| vec![] |
| } else { |
| vec![ty] |
| } |
| } |
| |
| Placeholder(..) | |
| Bound(..) | |
| Infer(..) => { |
| bug!("unexpected type `{:?}` in sized_constraint_for_ty", |
| ty) |
| } |
| }; |
| debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result); |
| result |
| } |
| } |
| |
| 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, |
| RustcEncodable, RustcDecodable, 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(FnTraitLangItem, None), |
| ClosureKind::FnMut => { |
| tcx.require_lang_item(FnMutTraitLangItem, None) |
| } |
| ClosureKind::FnOnce => { |
| tcx.require_lang_item(FnOnceTraitLangItem, None) |
| } |
| } |
| } |
| |
| /// Returns `true` if this a type that impls this closure kind |
| /// must also implement `other`. |
| pub fn extends(self, other: ty::ClosureKind) -> bool { |
| match (self, other) { |
| (ClosureKind::Fn, ClosureKind::Fn) => true, |
| (ClosureKind::Fn, ClosureKind::FnMut) => true, |
| (ClosureKind::Fn, ClosureKind::FnOnce) => true, |
| (ClosureKind::FnMut, ClosureKind::FnMut) => true, |
| (ClosureKind::FnMut, ClosureKind::FnOnce) => true, |
| (ClosureKind::FnOnce, ClosureKind::FnOnce) => true, |
| _ => false, |
| } |
| } |
| |
| /// 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<'tcx> TyS<'tcx> { |
| /// Iterator that walks `self` and any types reachable from |
| /// `self`, in depth-first order. Note that just walks the types |
| /// that appear in `self`, it does not descend into the fields of |
| /// structs or variants. For example: |
| /// |
| /// ```notrust |
| /// isize => { isize } |
| /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize } |
| /// [isize] => { [isize], isize } |
| /// ``` |
| pub fn walk(&'tcx self) -> TypeWalker<'tcx> { |
| TypeWalker::new(self) |
| } |
| |
| /// Iterator that walks the immediate children of `self`. Hence |
| /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]` |
| /// (but not `i32`, like `walk`). |
| pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> { |
| walk::walk_shallow(self) |
| } |
| |
| /// Walks `ty` and any types appearing within `ty`, invoking the |
| /// callback `f` on each type. If the callback returns `false`, then the |
| /// children of the current type are ignored. |
| /// |
| /// Note: prefer `ty.walk()` where possible. |
| pub fn maybe_walk<F>(&'tcx self, mut f: F) |
| where F: FnMut(Ty<'tcx>) -> bool |
| { |
| let mut walker = self.walk(); |
| while let Some(ty) = walker.next() { |
| if !f(ty) { |
| walker.skip_current_subtree(); |
| } |
| } |
| } |
| } |
| |
| impl BorrowKind { |
| pub fn from_mutbl(m: hir::Mutability) -> BorrowKind { |
| match m { |
| hir::MutMutable => MutBorrow, |
| hir::MutImmutable => 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::MutMutable, |
| ImmBorrow => hir::MutImmutable, |
| |
| // 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::MutMutable, |
| } |
| } |
| |
| pub fn to_user_str(&self) -> &'static str { |
| match *self { |
| MutBorrow => "mutable", |
| ImmBorrow => "immutable", |
| UniqueImmBorrow => "uniquely immutable", |
| } |
| } |
| } |
| |
| #[derive(Debug, Clone)] |
| pub enum Attributes<'tcx> { |
| Owned(Lrc<[ast::Attribute]>), |
| Borrowed(&'tcx [ast::Attribute]), |
| } |
| |
| impl<'tcx> ::std::ops::Deref for Attributes<'tcx> { |
| type Target = [ast::Attribute]; |
| |
| fn deref(&self) -> &[ast::Attribute] { |
| match self { |
| &Attributes::Owned(ref data) => &data, |
| &Attributes::Borrowed(data) => data |
| } |
| } |
| } |
| |
| #[derive(Debug, PartialEq, Eq)] |
| pub enum ImplOverlapKind { |
| /// These impls are always allowed to overlap. |
| Permitted, |
| /// 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 body_tables(self, body: hir::BodyId) -> &'tcx TypeckTables<'tcx> { |
| self.typeck_tables_of(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<Item = DefId> + 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<F: Fn(DefId) + sync::Sync + sync::Send>(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) -> Vec<AssocItem> { |
| self.associated_items(id) |
| .filter(|item| item.kind == AssocKind::Method && item.defaultness.has_value()) |
| .collect() |
| } |
| |
| pub fn trait_relevant_for_never(self, did: DefId) -> bool { |
| self.associated_items(did).any(|item| { |
| item.relevant_for_never() |
| }) |
| } |
| |
| pub fn opt_associated_item(self, def_id: DefId) -> Option<AssocItem> { |
| let is_associated_item = if let Some(hir_id) = self.hir().as_local_hir_id(def_id) { |
| match self.hir().get(hir_id) { |
| Node::TraitItem(_) | Node::ImplItem(_) => true, |
| _ => false, |
| } |
| } else { |
| match self.def_kind(def_id).expect("no def for `DefId`") { |
| DefKind::AssocConst |
| | DefKind::Method |
| | DefKind::AssocTy => true, |
| _ => false, |
| } |
| }; |
| |
| if is_associated_item { |
| Some(self.associated_item(def_id)) |
| } else { |
| None |
| } |
| } |
| |
| fn associated_item_from_trait_item_ref(self, |
| parent_def_id: DefId, |
| parent_vis: &hir::Visibility, |
| trait_item_ref: &hir::TraitItemRef) |
| -> AssocItem { |
| let def_id = self.hir().local_def_id(trait_item_ref.id.hir_id); |
| let (kind, has_self) = match trait_item_ref.kind { |
| hir::AssocItemKind::Const => (ty::AssocKind::Const, false), |
| hir::AssocItemKind::Method { has_self } => { |
| (ty::AssocKind::Method, has_self) |
| } |
| hir::AssocItemKind::Type => (ty::AssocKind::Type, false), |
| hir::AssocItemKind::OpaqueTy => bug!("only impls can have opaque types"), |
| }; |
| |
| AssocItem { |
| ident: trait_item_ref.ident, |
| kind, |
| // Visibility of trait items is inherited from their traits. |
| vis: Visibility::from_hir(parent_vis, trait_item_ref.id.hir_id, self), |
| defaultness: trait_item_ref.defaultness, |
| def_id, |
| container: TraitContainer(parent_def_id), |
| method_has_self_argument: has_self |
| } |
| } |
| |
| fn associated_item_from_impl_item_ref(self, |
| parent_def_id: DefId, |
| impl_item_ref: &hir::ImplItemRef) |
| -> AssocItem { |
| let def_id = self.hir().local_def_id(impl_item_ref.id.hir_id); |
| let (kind, has_self) = match impl_item_ref.kind { |
| hir::AssocItemKind::Const => (ty::AssocKind::Const, false), |
| hir::AssocItemKind::Method { has_self } => { |
| (ty::AssocKind::Method, has_self) |
| } |
| hir::AssocItemKind::Type => (ty::AssocKind::Type, false), |
| hir::AssocItemKind::OpaqueTy => (ty::AssocKind::OpaqueTy, false), |
| }; |
| |
| AssocItem { |
| ident: impl_item_ref.ident, |
| kind, |
| // Visibility of trait impl items doesn't matter. |
| vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.hir_id, self), |
| defaultness: impl_item_ref.defaultness, |
| def_id, |
| container: ImplContainer(parent_def_id), |
| method_has_self_argument: has_self |
| } |
| } |
| |
| pub fn field_index(self, hir_id: hir::HirId, tables: &TypeckTables<'_>) -> usize { |
| tables.field_indices().get(hir_id).cloned().expect("no index for a field") |
| } |
| |
| pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> { |
| variant.fields.iter().position(|field| { |
| self.hygienic_eq(ident, field.ident, variant.def_id) |
| }) |
| } |
| |
| pub fn associated_items(self, def_id: DefId) -> AssocItemsIterator<'tcx> { |
| // Ideally, we would use `-> impl Iterator` here, but it falls |
| // afoul of the conservative "capture [restrictions]" we put |
| // in place, so we use a hand-written iterator. |
| // |
| // [restrictions]: https://github.com/rust-lang/rust/issues/34511#issuecomment-373423999 |
| AssocItemsIterator { |
| tcx: self, |
| def_ids: self.associated_item_def_ids(def_id), |
| next_index: 0, |
| } |
| } |
| |
| /// 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<ImplOverlapKind> |
| { |
| let is_legit = if self.features().overlapping_marker_traits { |
| let trait1_is_empty = self.impl_trait_ref(def_id1) |
| .map_or(false, |trait_ref| { |
| self.associated_item_def_ids(trait_ref.def_id).is_empty() |
| }); |
| let trait2_is_empty = self.impl_trait_ref(def_id2) |
| .map_or(false, |trait_ref| { |
| self.associated_item_def_ids(trait_ref.def_id).is_empty() |
| }); |
| self.impl_polarity(def_id1) == self.impl_polarity(def_id2) |
| && trait1_is_empty |
| && trait2_is_empty |
| } else { |
| 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) |
| }; |
| self.impl_polarity(def_id1) == self.impl_polarity(def_id2) |
| && is_marker_impl(def_id1) |
| && is_marker_impl(def_id2) |
| }; |
| |
| if is_legit { |
| debug!("impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted)", |
| def_id1, def_id2); |
| Some(ImplOverlapKind::Permitted) |
| } 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, did) | Res::Def(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) |
| } |
| } |
| |
| pub fn item_name(self, id: DefId) -> Symbol { |
| if id.index == CRATE_DEF_INDEX { |
| self.original_crate_name(id.krate) |
| } else { |
| let def_key = self.def_key(id); |
| match def_key.disambiguated_data.data { |
| // The name of a constructor is that of its parent. |
| hir_map::DefPathData::Ctor => |
| self.item_name(DefId { |
| krate: id.krate, |
| index: def_key.parent.unwrap() |
| }), |
| _ => def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| { |
| bug!("item_name: no name for {:?}", self.def_path(id)); |
| }).as_symbol(), |
| } |
| } |
| } |
| |
| /// 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(did) => { |
| self.optimized_mir(did) |
| } |
| ty::InstanceDef::VtableShim(..) | |
| 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(id) = self.hir().as_local_hir_id(did) { |
| Attributes::Borrowed(self.hir().attrs(id)) |
| } else { |
| Attributes::Owned(self.item_attrs(did)) |
| } |
| } |
| |
| /// Determines whether an item is annotated with an attribute. |
| pub fn has_attr(self, did: DefId, attr: Symbol) -> bool { |
| attr::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<DefId> { |
| 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<DefId> { |
| let item = if def_id.krate != LOCAL_CRATE { |
| if let Some(DefKind::Method) = self.def_kind(def_id) { |
| Some(self.associated_item(def_id)) |
| } else { |
| None |
| } |
| } else { |
| self.opt_associated_item(def_id) |
| }; |
| |
| item.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<Span, Symbol> { |
| if impl_did.is_local() { |
| let hir_id = self.hir().as_local_hir_id(impl_did).unwrap(); |
| 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 |
| // `modern()` 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)) |
| } |
| |
| fn expansion_that_defined(self, scope: DefId) -> ExpnId { |
| match scope.krate { |
| LOCAL_CRATE => self.hir().definitions().expansion_that_defined(scope.index), |
| _ => ExpnId::root(), |
| } |
| } |
| |
| pub fn adjust_ident(self, mut ident: Ident, scope: DefId) -> Ident { |
| ident.span.modernize_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.modernize_and_adjust(self.expansion_that_defined(scope)) { |
| Some(actual_expansion) => |
| self.hir().definitions().parent_module_of_macro_def(actual_expansion), |
| None => self.hir().get_module_parent(block), |
| }; |
| (ident, scope) |
| } |
| } |
| |
| pub struct AssocItemsIterator<'tcx> { |
| tcx: TyCtxt<'tcx>, |
| def_ids: &'tcx [DefId], |
| next_index: usize, |
| } |
| |
| impl Iterator for AssocItemsIterator<'_> { |
| type Item = AssocItem; |
| |
| fn next(&mut self) -> Option<AssocItem> { |
| let def_id = self.def_ids.get(self.next_index)?; |
| self.next_index += 1; |
| Some(self.tcx.associated_item(*def_id)) |
| } |
| } |
| |
| fn associated_item(tcx: TyCtxt<'_>, def_id: DefId) -> AssocItem { |
| let id = tcx.hir().as_local_hir_id(def_id).unwrap(); |
| let parent_id = tcx.hir().get_parent_item(id); |
| let parent_def_id = tcx.hir().local_def_id(parent_id); |
| let parent_item = tcx.hir().expect_item(parent_id); |
| match parent_item.node { |
| hir::ItemKind::Impl(.., ref impl_item_refs) => { |
| if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.hir_id == id) { |
| let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id, |
| impl_item_ref); |
| debug_assert_eq!(assoc_item.def_id, def_id); |
| return assoc_item; |
| } |
| } |
| |
| hir::ItemKind::Trait(.., ref trait_item_refs) => { |
| if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.hir_id == id) { |
| let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id, |
| &parent_item.vis, |
| trait_item_ref); |
| debug_assert_eq!(assoc_item.def_id, def_id); |
| return assoc_item; |
| } |
| } |
| |
| _ => { } |
| } |
| |
| span_bug!(parent_item.span, |
| "unexpected parent of trait or impl item or item not found: {:?}", |
| parent_item.node) |
| } |
| |
| #[derive(Clone, HashStable)] |
| pub struct AdtSizedConstraint<'tcx>(pub &'tcx [Ty<'tcx>]); |
| |
| /// Calculates the `Sized` constraint. |
| /// |
| /// In fact, there are only a few options for the types in the constraint: |
| /// - an obviously-unsized type |
| /// - a type parameter or projection whose Sizedness can't be known |
| /// - a tuple of type parameters or projections, if there are multiple |
| /// such. |
| /// - a Error, if a type contained itself. The representability |
| /// check should catch this case. |
| fn adt_sized_constraint(tcx: TyCtxt<'_>, def_id: DefId) -> AdtSizedConstraint<'_> { |
| let def = tcx.adt_def(def_id); |
| |
| let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| { |
| v.fields.last() |
| }).flat_map(|f| { |
| def.sized_constraint_for_ty(tcx, tcx.type_of(f.did)) |
| })); |
| |
| debug!("adt_sized_constraint: {:?} => {:?}", def, result); |
| |
| AdtSizedConstraint(result) |
| } |
| |
| fn associated_item_def_ids(tcx: TyCtxt<'_>, def_id: DefId) -> &[DefId] { |
| let id = tcx.hir().as_local_hir_id(def_id).unwrap(); |
| let item = tcx.hir().expect_item(id); |
| match item.node { |
| hir::ItemKind::Trait(.., ref trait_item_refs) => { |
| tcx.arena.alloc_from_iter( |
| trait_item_refs.iter() |
| .map(|trait_item_ref| trait_item_ref.id) |
| .map(|id| tcx.hir().local_def_id(id.hir_id)) |
| ) |
| } |
| hir::ItemKind::Impl(.., ref impl_item_refs) => { |
| tcx.arena.alloc_from_iter( |
| impl_item_refs.iter() |
| .map(|impl_item_ref| impl_item_ref.id) |
| .map(|id| tcx.hir().local_def_id(id.hir_id)) |
| ) |
| } |
| hir::ItemKind::TraitAlias(..) => &[], |
| _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait") |
| } |
| } |
| |
| fn def_span(tcx: TyCtxt<'_>, def_id: DefId) -> Span { |
| tcx.hir().span_if_local(def_id).unwrap() |
| } |
| |
| /// If the given `DefId` describes an item belonging to a trait, |
| /// returns the `DefId` of the trait that the trait item belongs to; |
| /// otherwise, returns `None`. |
| fn trait_of_item(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> { |
| tcx.opt_associated_item(def_id) |
| .and_then(|associated_item| { |
| match associated_item.container { |
| TraitContainer(def_id) => Some(def_id), |
| ImplContainer(_) => None |
| } |
| }) |
| } |
| |
| /// 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<DefId> { |
| if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) { |
| if let Node::Item(item) = tcx.hir().get(hir_id) { |
| if let hir::ItemKind::OpaqueTy(ref opaque_ty) = item.node { |
| return opaque_ty.impl_trait_fn; |
| } |
| } |
| } |
| None |
| } |
| |
| /// See `ParamEnv` struct definition for details. |
| fn param_env(tcx: TyCtxt<'_>, def_id: DefId) -> ParamEnv<'_> { |
| // The param_env of an impl Trait type is its defining function's param_env |
| if let Some(parent) = is_impl_trait_defn(tcx, def_id) { |
| return param_env(tcx, parent); |
| } |
| // Compute the bounds on Self and the type parameters. |
| |
| let InstantiatedPredicates { predicates } = |
| tcx.predicates_of(def_id).instantiate_identity(tcx); |
| |
| // Finally, we have to normalize the bounds in the environment, in |
| // case they contain any associated type projections. This process |
| // can yield errors if the put in illegal associated types, like |
| // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We |
| // report these errors right here; this doesn't actually feel |
| // right to me, because constructing the environment feels like a |
| // kind of a "idempotent" action, but I'm not sure where would be |
| // a better place. In practice, we construct environments for |
| // every fn once during type checking, and we'll abort if there |
| // are any errors at that point, so after type checking you can be |
| // sure that this will succeed without errors anyway. |
| |
| let unnormalized_env = ty::ParamEnv::new( |
| tcx.intern_predicates(&predicates), |
| traits::Reveal::UserFacing, |
| if tcx.sess.opts.debugging_opts.chalk { Some(def_id) } else { None } |
| ); |
| |
| let body_id = tcx.hir().as_local_hir_id(def_id).map_or(hir::DUMMY_HIR_ID, |id| { |
| tcx.hir().maybe_body_owned_by(id).map_or(id, |body| body.hir_id) |
| }); |
| let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id); |
| traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause) |
| } |
| |
| fn crate_disambiguator(tcx: TyCtxt<'_>, crate_num: CrateNum) -> CrateDisambiguator { |
| assert_eq!(crate_num, LOCAL_CRATE); |
| tcx.sess.local_crate_disambiguator() |
| } |
| |
| fn original_crate_name(tcx: TyCtxt<'_>, crate_num: CrateNum) -> Symbol { |
| assert_eq!(crate_num, LOCAL_CRATE); |
| tcx.crate_name.clone() |
| } |
| |
| fn crate_hash(tcx: TyCtxt<'_>, crate_num: CrateNum) -> Svh { |
| assert_eq!(crate_num, LOCAL_CRATE); |
| tcx.hir().crate_hash |
| } |
| |
| fn instance_def_size_estimate<'tcx>(tcx: TyCtxt<'tcx>, instance_def: InstanceDef<'tcx>) -> usize { |
| match instance_def { |
| InstanceDef::Item(..) | |
| InstanceDef::DropGlue(..) => { |
| let mir = tcx.instance_mir(instance_def); |
| mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum() |
| }, |
| // Estimate the size of other compiler-generated shims to be 1. |
| _ => 1 |
| } |
| } |
| |
| /// If `def_id` is an issue 33140 hack impl, returns its self type; otherwise, returns `None`. |
| /// |
| /// See [`ImplOverlapKind::Issue33140`] for more details. |
| fn issue33140_self_ty(tcx: TyCtxt<'_>, def_id: DefId) -> Option<Ty<'_>> { |
| debug!("issue33140_self_ty({:?})", def_id); |
| |
| let trait_ref = tcx.impl_trait_ref(def_id).unwrap_or_else(|| { |
| bug!("issue33140_self_ty called on inherent impl {:?}", def_id) |
| }); |
| |
| debug!("issue33140_self_ty({:?}), trait-ref={:?}", def_id, trait_ref); |
| |
| let is_marker_like = |
| tcx.impl_polarity(def_id) == hir::ImplPolarity::Positive && |
| tcx.associated_item_def_ids(trait_ref.def_id).is_empty(); |
| |
| // Check whether these impls would be ok for a marker trait. |
| if !is_marker_like { |
| debug!("issue33140_self_ty - not marker-like!"); |
| return None; |
| } |
| |
| // impl must be `impl Trait for dyn Marker1 + Marker2 + ...` |
| if trait_ref.substs.len() != 1 { |
| debug!("issue33140_self_ty - impl has substs!"); |
| return None; |
| } |
| |
| let predicates = tcx.predicates_of(def_id); |
| if predicates.parent.is_some() || !predicates.predicates.is_empty() { |
| debug!("issue33140_self_ty - impl has predicates {:?}!", predicates); |
| return None; |
| } |
| |
| let self_ty = trait_ref.self_ty(); |
| let self_ty_matches = match self_ty.sty { |
| ty::Dynamic(ref data, ty::ReStatic) => data.principal().is_none(), |
| _ => false |
| }; |
| |
| if self_ty_matches { |
| debug!("issue33140_self_ty - MATCHES!"); |
| Some(self_ty) |
| } else { |
| debug!("issue33140_self_ty - non-matching self type"); |
| None |
| } |
| } |
| |
| pub fn provide(providers: &mut ty::query::Providers<'_>) { |
| context::provide(providers); |
| erase_regions::provide(providers); |
| layout::provide(providers); |
| util::provide(providers); |
| constness::provide(providers); |
| *providers = ty::query::Providers { |
| associated_item, |
| associated_item_def_ids, |
| adt_sized_constraint, |
| def_span, |
| param_env, |
| trait_of_item, |
| crate_disambiguator, |
| original_crate_name, |
| crate_hash, |
| trait_impls_of: trait_def::trait_impls_of_provider, |
| instance_def_size_estimate, |
| issue33140_self_ty, |
| ..*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<Vec<DefId>>, |
| } |
| |
| #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)] |
| pub struct SymbolName { |
| // FIXME: we don't rely on interning or equality here - better have |
| // this be a `&'tcx str`. |
| pub name: InternedString |
| } |
| |
| impl_stable_hash_for!(struct self::SymbolName { |
| name |
| }); |
| |
| impl SymbolName { |
| pub fn new(name: &str) -> SymbolName { |
| SymbolName { |
| name: InternedString::intern(name) |
| } |
| } |
| } |
| |
| impl fmt::Display for SymbolName { |
| fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { |
| fmt::Display::fmt(&self.name, fmt) |
| } |
| } |
| |
| impl fmt::Debug for SymbolName { |
| fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { |
| fmt::Display::fmt(&self.name, fmt) |
| } |
| } |