| // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| pub use self::Variance::*; |
| pub use self::AssociatedItemContainer::*; |
| pub use self::BorrowKind::*; |
| pub use self::IntVarValue::*; |
| pub use self::LvaluePreference::*; |
| pub use self::fold::TypeFoldable; |
| |
| use hir::{map as hir_map, FreevarMap, TraitMap}; |
| use hir::def::{Def, CtorKind, ExportMap}; |
| use hir::def_id::{CrateNum, DefId, DefIndex, CRATE_DEF_INDEX, LOCAL_CRATE}; |
| use hir::map::DefPathData; |
| use ich::StableHashingContext; |
| use middle::const_val::ConstVal; |
| use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem}; |
| use middle::privacy::AccessLevels; |
| use middle::resolve_lifetime::ObjectLifetimeDefault; |
| use mir::Mir; |
| use mir::GeneratorLayout; |
| use traits; |
| use ty; |
| use ty::subst::{Subst, Substs}; |
| use ty::util::IntTypeExt; |
| use ty::walk::TypeWalker; |
| use util::common::ErrorReported; |
| use util::nodemap::{NodeSet, DefIdMap, FxHashMap, FxHashSet}; |
| |
| use serialize::{self, Encodable, Encoder}; |
| use std::collections::BTreeMap; |
| use std::cmp; |
| use std::fmt; |
| use std::hash::{Hash, Hasher}; |
| use std::iter::FromIterator; |
| use std::ops::Deref; |
| use std::rc::Rc; |
| use std::slice; |
| use std::vec::IntoIter; |
| use std::mem; |
| use syntax::ast::{self, DUMMY_NODE_ID, Name, Ident, NodeId}; |
| use syntax::attr; |
| use syntax::ext::hygiene::{Mark, SyntaxContext}; |
| use syntax::symbol::{Symbol, InternedString}; |
| use syntax_pos::{DUMMY_SP, Span}; |
| use rustc_const_math::ConstInt; |
| |
| use rustc_data_structures::accumulate_vec::IntoIter as AccIntoIter; |
| use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult, |
| HashStable}; |
| use rustc_data_structures::transitive_relation::TransitiveRelation; |
| |
| use hir; |
| |
| pub use self::sty::{Binder, DebruijnIndex}; |
| pub use self::sty::{FnSig, GenSig, PolyFnSig, PolyGenSig}; |
| pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate}; |
| pub use self::sty::{ClosureSubsts, GeneratorInterior, TypeAndMut}; |
| pub use self::sty::{TraitRef, TypeVariants, 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, RegionVid, SkolemizedRegionVid}; |
| pub use self::sty::BoundRegion::*; |
| pub use self::sty::InferTy::*; |
| pub use self::sty::RegionKind::*; |
| pub use self::sty::TypeVariants::*; |
| |
| pub use self::binding::BindingMode; |
| pub use self::binding::BindingMode::*; |
| |
| pub use self::context::{TyCtxt, GlobalArenas, tls, keep_local}; |
| pub use self::context::{Lift, TypeckTables}; |
| |
| pub use self::instance::{Instance, InstanceDef}; |
| |
| pub use self::trait_def::TraitDef; |
| |
| pub use self::maps::queries; |
| |
| pub mod adjustment; |
| pub mod binding; |
| pub mod cast; |
| pub mod error; |
| mod erase_regions; |
| pub mod fast_reject; |
| pub mod fold; |
| pub mod inhabitedness; |
| pub mod item_path; |
| pub mod layout; |
| pub mod _match; |
| pub mod maps; |
| pub mod outlives; |
| 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 flags; |
| mod instance; |
| mod structural_impls; |
| mod sty; |
| |
| // Data types |
| |
| /// The complete set of all analyses described in this module. This is |
| /// produced by the driver and fed to trans and later passes. |
| /// |
| /// NB: These contents are being migrated into queries using the |
| /// *on-demand* infrastructure. |
| #[derive(Clone)] |
| pub struct CrateAnalysis { |
| pub access_levels: Rc<AccessLevels>, |
| pub name: String, |
| pub glob_map: Option<hir::GlobMap>, |
| } |
| |
| #[derive(Clone)] |
| pub struct Resolutions { |
| pub freevars: FreevarMap, |
| pub trait_map: TraitMap, |
| pub maybe_unused_trait_imports: NodeSet, |
| pub maybe_unused_extern_crates: Vec<(NodeId, Span)>, |
| pub export_map: ExportMap, |
| } |
| |
| #[derive(Clone, Copy, PartialEq, Eq, Debug)] |
| pub enum AssociatedItemContainer { |
| TraitContainer(DefId), |
| ImplContainer(DefId), |
| } |
| |
| impl AssociatedItemContainer { |
| 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, Eq)] |
| pub struct AssociatedItem { |
| pub def_id: DefId, |
| pub name: Name, |
| pub kind: AssociatedKind, |
| pub vis: Visibility, |
| pub defaultness: hir::Defaultness, |
| pub container: AssociatedItemContainer, |
| |
| /// 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)] |
| pub enum AssociatedKind { |
| Const, |
| Method, |
| Type |
| } |
| |
| impl AssociatedItem { |
| pub fn def(&self) -> Def { |
| match self.kind { |
| AssociatedKind::Const => Def::AssociatedConst(self.def_id), |
| AssociatedKind::Method => Def::Method(self.def_id), |
| AssociatedKind::Type => Def::AssociatedTy(self.def_id), |
| } |
| } |
| |
| /// Tests whether the associated item admits a non-trivial implementation |
| /// for ! |
| pub fn relevant_for_never<'tcx>(&self) -> bool { |
| match self.kind { |
| AssociatedKind::Const => true, |
| AssociatedKind::Type => true, |
| // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited. |
| AssociatedKind::Method => !self.method_has_self_argument, |
| } |
| } |
| |
| pub fn signature<'a, 'tcx>(&self, tcx: &TyCtxt<'a, 'tcx, 'tcx>) -> String { |
| match self.kind { |
| ty::AssociatedKind::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)`. |
| format!("{}", tcx.fn_sig(self.def_id).skip_binder()) |
| } |
| ty::AssociatedKind::Type => format!("type {};", self.name.to_string()), |
| ty::AssociatedKind::Const => { |
| format!("const {}: {:?};", self.name.to_string(), tcx.type_of(self.def_id)) |
| } |
| } |
| } |
| } |
| |
| #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)] |
| 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<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, '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: NodeId, tcx: TyCtxt) -> Self { |
| match *visibility { |
| hir::Public => Visibility::Public, |
| hir::Visibility::Crate => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)), |
| hir::Visibility::Restricted { ref path, .. } => match path.def { |
| // 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. |
| Def::Err => Visibility::Public, |
| def => Visibility::Restricted(def.def_id()), |
| }, |
| hir::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) |
| } |
| } |
| |
| #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)] |
| 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. |
| pub struct CrateVariancesMap { |
| /// This relation tracks the dependencies between the variance of |
| /// various items. In particular, if `a < b`, then the variance of |
| /// `a` depends on the sources of `b`. |
| pub dependencies: TransitiveRelation<DefId>, |
| |
| /// 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, Rc<Vec<ty::Variance>>>, |
| |
| /// An empty vector, useful for cloning. |
| pub empty_variance: Rc<Vec<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_SELF = 1 << 1; |
| const HAS_TY_INFER = 1 << 2; |
| const HAS_RE_INFER = 1 << 3; |
| const HAS_RE_SKOL = 1 << 4; |
| const HAS_RE_EARLY_BOUND = 1 << 5; |
| const HAS_FREE_REGIONS = 1 << 6; |
| const HAS_TY_ERR = 1 << 7; |
| const HAS_PROJECTION = 1 << 8; |
| |
| // FIXME: Rename this to the actual property since it's used for generators too |
| const HAS_TY_CLOSURE = 1 << 9; |
| |
| // true if there are "names" of types and regions and so forth |
| // that are local to a particular fn |
| const HAS_LOCAL_NAMES = 1 << 10; |
| |
| // Present if the type belongs in a local type context. |
| // Only set for TyInfer other than Fresh. |
| const KEEP_IN_LOCAL_TCX = 1 << 11; |
| |
| // Is there a projection that does not involve a bound region? |
| // Currently we can't normalize projections w/ bound regions. |
| const HAS_NORMALIZABLE_PROJECTION = 1 << 12; |
| |
| const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits | |
| TypeFlags::HAS_SELF.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_SELF.bits | |
| TypeFlags::HAS_TY_INFER.bits | |
| TypeFlags::HAS_RE_INFER.bits | |
| TypeFlags::HAS_RE_SKOL.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_LOCAL_NAMES.bits | |
| TypeFlags::KEEP_IN_LOCAL_TCX.bits; |
| } |
| } |
| |
| pub struct TyS<'tcx> { |
| pub sty: TypeVariants<'tcx>, |
| pub flags: TypeFlags, |
| |
| // the maximal depth of any bound regions appearing in this type. |
| region_depth: u32, |
| } |
| |
| impl<'tcx> PartialEq for TyS<'tcx> { |
| #[inline] |
| fn eq(&self, other: &TyS<'tcx>) -> bool { |
| // (self as *const _) == (other as *const _) |
| (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>) |
| } |
| } |
| 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 { |
| TypeVariants::TyBool | |
| TypeVariants::TyChar | |
| TypeVariants::TyInt(_) | |
| TypeVariants::TyUint(_) | |
| TypeVariants::TyFloat(_) | |
| TypeVariants::TyInfer(InferTy::IntVar(_)) | |
| TypeVariants::TyInfer(InferTy::FloatVar(_)) | |
| TypeVariants::TyInfer(InferTy::FreshIntTy(_)) | |
| TypeVariants::TyInfer(InferTy::FreshFloatTy(_)) => true, |
| TypeVariants::TyRef(_, x) => x.ty.is_primitive_ty(), |
| _ => false, |
| } |
| } |
| |
| pub fn is_suggestable(&self) -> bool { |
| match self.sty { |
| TypeVariants::TyAnon(..) | |
| TypeVariants::TyFnDef(..) | |
| TypeVariants::TyFnPtr(..) | |
| TypeVariants::TyDynamic(..) | |
| TypeVariants::TyClosure(..) | |
| TypeVariants::TyInfer(..) | |
| TypeVariants::TyProjection(..) => false, |
| _ => true, |
| } |
| } |
| } |
| |
| impl<'gcx> HashStable<StableHashingContext<'gcx>> for ty::TyS<'gcx> { |
| fn hash_stable<W: StableHasherResult>(&self, |
| hcx: &mut StableHashingContext<'gcx>, |
| 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: _, |
| region_depth: _, |
| } = *self; |
| |
| sty.hash_stable(hcx, hasher); |
| } |
| } |
| |
| pub type Ty<'tcx> = &'tcx TyS<'tcx>; |
| |
| impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {} |
| impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {} |
| |
| /// 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 + length for both |
| /// equality comparisons and hashing. |
| #[derive(Debug, RustcEncodable)] |
| pub struct Slice<T>([T]); |
| |
| impl<T> PartialEq for Slice<T> { |
| #[inline] |
| fn eq(&self, other: &Slice<T>) -> bool { |
| (&self.0 as *const [T]) == (&other.0 as *const [T]) |
| } |
| } |
| impl<T> Eq for Slice<T> {} |
| |
| impl<T> Hash for Slice<T> { |
| fn hash<H: Hasher>(&self, s: &mut H) { |
| (self.as_ptr(), self.len()).hash(s) |
| } |
| } |
| |
| impl<T> Deref for Slice<T> { |
| type Target = [T]; |
| fn deref(&self) -> &[T] { |
| &self.0 |
| } |
| } |
| |
| impl<'a, T> IntoIterator for &'a Slice<T> { |
| type Item = &'a T; |
| type IntoIter = <&'a [T] as IntoIterator>::IntoIter; |
| fn into_iter(self) -> Self::IntoIter { |
| self[..].iter() |
| } |
| } |
| |
| impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {} |
| |
| impl<T> Slice<T> { |
| pub fn empty<'a>() -> &'a Slice<T> { |
| unsafe { |
| mem::transmute(slice::from_raw_parts(0x1 as *const T, 0)) |
| } |
| } |
| } |
| |
| /// Upvars do not get their own node-id. 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)] |
| pub struct UpvarId { |
| pub var_id: hir::HirId, |
| pub closure_expr_id: DefIndex, |
| } |
| |
| #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)] |
| 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)] |
| 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)] |
| 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 UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>; |
| |
| #[derive(Copy, Clone)] |
| pub struct ClosureUpvar<'tcx> { |
| pub def: Def, |
| pub span: Span, |
| pub ty: Ty<'tcx>, |
| } |
| |
| #[derive(Clone, Copy, PartialEq)] |
| pub enum IntVarValue { |
| IntType(ast::IntTy), |
| UintType(ast::UintTy), |
| } |
| |
| #[derive(Copy, Clone, RustcEncodable, RustcDecodable)] |
| pub struct TypeParameterDef { |
| pub name: Name, |
| pub def_id: DefId, |
| pub index: u32, |
| pub has_default: bool, |
| pub object_lifetime_default: ObjectLifetimeDefault, |
| |
| /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute |
| /// on generic parameter `T`, asserts data behind the parameter |
| /// `T` won't be accessed during the parent type's `Drop` impl. |
| pub pure_wrt_drop: bool, |
| |
| pub synthetic: Option<hir::SyntheticTyParamKind>, |
| } |
| |
| #[derive(Copy, Clone, RustcEncodable, RustcDecodable)] |
| pub struct RegionParameterDef { |
| pub name: Name, |
| pub def_id: DefId, |
| pub index: u32, |
| |
| /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute |
| /// on generic parameter `'a`, asserts data of lifetime `'a` |
| /// won't be accessed during the parent type's `Drop` impl. |
| pub pure_wrt_drop: bool, |
| } |
| |
| impl RegionParameterDef { |
| pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion { |
| ty::EarlyBoundRegion { |
| def_id: self.def_id, |
| index: self.index, |
| name: self.name, |
| } |
| } |
| |
| pub fn to_bound_region(&self) -> ty::BoundRegion { |
| self.to_early_bound_region_data().to_bound_region() |
| } |
| } |
| |
| impl ty::EarlyBoundRegion { |
| pub fn to_bound_region(&self) -> ty::BoundRegion { |
| ty::BoundRegion::BrNamed(self.def_id, self.name) |
| } |
| } |
| |
| /// Information about the formal type/lifetime parameters associated |
| /// with an item or method. Analogous to hir::Generics. |
| /// |
| /// Note that in the presence of a `Self` parameter, the ordering here |
| /// is different from the ordering in a Substs. Substs are ordered as |
| /// Self, *Regions, *Other Type Params, (...child generics) |
| /// while this struct is ordered as |
| /// regions = Regions |
| /// types = [Self, *Other Type Params] |
| #[derive(Clone, Debug, RustcEncodable, RustcDecodable)] |
| pub struct Generics { |
| pub parent: Option<DefId>, |
| pub parent_regions: u32, |
| pub parent_types: u32, |
| pub regions: Vec<RegionParameterDef>, |
| pub types: Vec<TypeParameterDef>, |
| |
| /// Reverse map to each `TypeParameterDef`'s `index` field, from |
| /// `def_id.index` (`def_id.krate` is the same as the item's). |
| pub type_param_to_index: BTreeMap<DefIndex, u32>, |
| |
| pub has_self: bool, |
| pub has_late_bound_regions: Option<Span>, |
| } |
| |
| impl<'a, 'gcx, 'tcx> Generics { |
| pub fn parent_count(&self) -> usize { |
| self.parent_regions as usize + self.parent_types as usize |
| } |
| |
| pub fn own_count(&self) -> usize { |
| self.regions.len() + self.types.len() |
| } |
| |
| pub fn count(&self) -> usize { |
| self.parent_count() + self.own_count() |
| } |
| |
| pub fn region_param(&'tcx self, |
| param: &EarlyBoundRegion, |
| tcx: TyCtxt<'a, 'gcx, 'tcx>) |
| -> &'tcx RegionParameterDef |
| { |
| if let Some(index) = param.index.checked_sub(self.parent_count() as u32) { |
| &self.regions[index as usize - self.has_self as usize] |
| } else { |
| tcx.generics_of(self.parent.expect("parent_count>0 but no parent?")) |
| .region_param(param, tcx) |
| } |
| } |
| |
| /// Returns the `TypeParameterDef` associated with this `ParamTy`. |
| pub fn type_param(&'tcx self, |
| param: &ParamTy, |
| tcx: TyCtxt<'a, 'gcx, 'tcx>) |
| -> &TypeParameterDef { |
| if let Some(idx) = param.idx.checked_sub(self.parent_count() as u32) { |
| // non-Self type parameters are always offset by exactly |
| // `self.regions.len()`. In the absence of a Self, this is obvious, |
| // but even in the absence of a `Self` we just have to "compensate" |
| // for the regions: |
| // |
| // For example, for `trait Foo<'a, 'b, T1, T2>`, the |
| // situation is: |
| // Substs: |
| // 0 1 2 3 4 |
| // Self 'a 'b T1 T2 |
| // generics.types: |
| // 0 1 2 |
| // Self T1 T2 |
| // And it can be seen that to move from a substs offset to a |
| // generics offset you just have to offset by the number of regions. |
| let type_param_offset = self.regions.len(); |
| if let Some(idx) = (idx as usize).checked_sub(type_param_offset) { |
| assert!(!(self.has_self && idx == 0)); |
| &self.types[idx] |
| } else { |
| assert!(self.has_self && idx == 0); |
| &self.types[0] |
| } |
| } else { |
| tcx.generics_of(self.parent.expect("parent_count>0 but no parent?")) |
| .type_param(param, tcx) |
| } |
| } |
| } |
| |
| /// Bounds on generics. |
| #[derive(Clone, Default)] |
| pub struct GenericPredicates<'tcx> { |
| pub parent: Option<DefId>, |
| pub predicates: Vec<Predicate<'tcx>>, |
| } |
| |
| impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {} |
| impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {} |
| |
| impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> { |
| pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>) |
| -> InstantiatedPredicates<'tcx> { |
| let mut instantiated = InstantiatedPredicates::empty(); |
| self.instantiate_into(tcx, &mut instantiated, substs); |
| instantiated |
| } |
| pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>) |
| -> InstantiatedPredicates<'tcx> { |
| InstantiatedPredicates { |
| predicates: self.predicates.subst(tcx, substs) |
| } |
| } |
| |
| fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, |
| instantiated: &mut InstantiatedPredicates<'tcx>, |
| substs: &Substs<'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<'a, 'gcx, 'tcx>) |
| -> InstantiatedPredicates<'tcx> { |
| let mut instantiated = InstantiatedPredicates::empty(); |
| self.instantiate_identity_into(tcx, &mut instantiated); |
| instantiated |
| } |
| |
| fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, '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) |
| } |
| |
| pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, '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)] |
| 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 `T1 == T2`. |
| Equate(PolyEquatePredicate<'tcx>), |
| |
| /// where 'a : 'b |
| RegionOutlives(PolyRegionOutlivesPredicate<'tcx>), |
| |
| /// where T : 'a |
| TypeOutlives(PolyTypeOutlivesPredicate<'tcx>), |
| |
| /// where <T as TraitRef>::Name == X, approximately. |
| /// See `ProjectionPredicate` struct for details. |
| Projection(PolyProjectionPredicate<'tcx>), |
| |
| /// no syntax: T WF |
| 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, ClosureKind), |
| |
| /// `T1 <: T2` |
| Subtype(PolySubtypePredicate<'tcx>), |
| |
| /// Constant initializer must evaluate successfully. |
| ConstEvaluatable(DefId, &'tcx Substs<'tcx>), |
| } |
| |
| impl<'a, 'gcx, '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<'a, 'gcx, '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.0.substs; |
| match *self { |
| Predicate::Trait(ty::Binder(ref data)) => |
| Predicate::Trait(ty::Binder(data.subst(tcx, substs))), |
| Predicate::Equate(ty::Binder(ref data)) => |
| Predicate::Equate(ty::Binder(data.subst(tcx, substs))), |
| Predicate::Subtype(ty::Binder(ref data)) => |
| Predicate::Subtype(ty::Binder(data.subst(tcx, substs))), |
| Predicate::RegionOutlives(ty::Binder(ref data)) => |
| Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))), |
| Predicate::TypeOutlives(ty::Binder(ref data)) => |
| Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))), |
| Predicate::Projection(ty::Binder(ref data)) => |
| Predicate::Projection(ty::Binder(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, kind) => |
| Predicate::ClosureKind(closure_def_id, kind), |
| Predicate::ConstEvaluatable(def_id, const_substs) => |
| Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)), |
| } |
| } |
| } |
| |
| #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)] |
| 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 def-id does not care about regions |
| self.0.def_id() |
| } |
| } |
| |
| #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)] |
| pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1` |
| pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>; |
| |
| #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)] |
| pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B` |
| pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>; |
| pub type PolyRegionOutlivesPredicate<'tcx> = PolyOutlivesPredicate<ty::Region<'tcx>, |
| ty::Region<'tcx>>; |
| pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>; |
| |
| #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)] |
| 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)] |
| pub struct ProjectionPredicate<'tcx> { |
| pub projection_ty: ProjectionTy<'tcx>, |
| pub ty: Ty<'tcx>, |
| } |
| |
| pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>; |
| |
| impl<'tcx> PolyProjectionPredicate<'tcx> { |
| 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. |
| ty::Binder(self.0.projection_ty.trait_ref(tcx)) |
| } |
| |
| pub fn ty(&self) -> Binder<Ty<'tcx>> { |
| Binder(self.skip_binder().ty) // preserves binding levels |
| } |
| } |
| |
| 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> { |
| assert!(!self.has_escaping_regions()); |
| ty::Binder(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> { |
| // we're about to add a binder, so let's check that we don't |
| // accidentally capture anything, or else that might be some |
| // weird debruijn accounting. |
| assert!(!self.has_escaping_regions()); |
| |
| ty::Predicate::Trait(ty::Binder(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 PolyEquatePredicate<'tcx> { |
| fn to_predicate(&self) -> Predicate<'tcx> { |
| Predicate::Equate(self.clone()) |
| } |
| } |
| |
| 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()) |
| } |
| } |
| |
| 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(&self) -> IntoIter<Ty<'tcx>> { |
| let vec: Vec<_> = match *self { |
| ty::Predicate::Trait(ref data) => { |
| data.skip_binder().input_types().collect() |
| } |
| ty::Predicate::Equate(ty::Binder(ref data)) => { |
| vec![data.0, data.1] |
| } |
| ty::Predicate::Subtype(ty::Binder(SubtypePredicate { a, b, a_is_expected: _ })) => { |
| vec![a, b] |
| } |
| ty::Predicate::TypeOutlives(ty::Binder(ref data)) => { |
| vec![data.0] |
| } |
| ty::Predicate::RegionOutlives(..) => { |
| vec![] |
| } |
| ty::Predicate::Projection(ref data) => { |
| data.0.projection_ty.substs.types().chain(Some(data.0.ty)).collect() |
| } |
| ty::Predicate::WellFormed(data) => { |
| vec![data] |
| } |
| ty::Predicate::ObjectSafe(_trait_def_id) => { |
| vec![] |
| } |
| ty::Predicate::ClosureKind(_closure_def_id, _kind) => { |
| vec![] |
| } |
| ty::Predicate::ConstEvaluatable(_, substs) => { |
| substs.types().collect() |
| } |
| }; |
| |
| // The only reason to collect into a vector here is that I was |
| // too lazy to make the full (somewhat complicated) iterator |
| // type that would be needed here. But I wanted this fn to |
| // return an iterator conceptually, rather than a `Vec`, so as |
| // to be closer to `Ty::walk`. |
| vec.into_iter() |
| } |
| |
| 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::Equate(..) | |
| Predicate::Subtype(..) | |
| Predicate::RegionOutlives(..) | |
| Predicate::WellFormed(..) | |
| Predicate::ObjectSafe(..) | |
| Predicate::ClosureKind(..) | |
| Predicate::TypeOutlives(..) | |
| 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)] |
| 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() |
| } |
| } |
| |
| /// 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)] |
| pub struct ParamEnv<'tcx> { |
| /// Obligations that the caller must satisfy. This is basically |
| /// the set of bounds on the in-scope type parameters, translated |
| /// into Obligations, and elaborated and normalized. |
| pub caller_bounds: &'tcx Slice<ty::Predicate<'tcx>>, |
| |
| /// Typically, this is `Reveal::UserFacing`, but during trans we |
| /// want `Reveal::All` -- note that this is always paired with an |
| /// empty environment. To get that, use `ParamEnv::reveal()`. |
| pub reveal: traits::Reveal, |
| } |
| |
| impl<'tcx> ParamEnv<'tcx> { |
| /// Creates a suitable environment in which to perform trait |
| /// queries on the given value. This will either be `self` *or* |
| /// the empty environment, depending on whether `value` references |
| /// type parameters that are in scope. (If it doesn't, then any |
| /// judgements should be completely independent of the context, |
| /// and hence we can safely use the empty environment so as to |
| /// enable more sharing across functions.) |
| /// |
| /// NB: This is a mildly dubious thing to do, in that a function |
| /// (or other environment) might have wacky where-clauses like |
| /// `where Box<u32>: Copy`, which are clearly never |
| /// satisfiable. The code will at present ignore these, |
| /// effectively, when type-checking the body of said |
| /// function. This preserves existing behavior in any |
| /// case. --nmatsakis |
| pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> { |
| assert!(!value.needs_infer()); |
| if value.has_param_types() || value.has_self_ty() { |
| ParamEnvAnd { |
| param_env: self, |
| value, |
| } |
| } else { |
| ParamEnvAnd { |
| param_env: ParamEnv::empty(self.reveal), |
| 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<'gcx, T> HashStable<StableHashingContext<'gcx>> for ParamEnvAnd<'gcx, T> |
| where T: HashStable<StableHashingContext<'gcx>> |
| { |
| fn hash_stable<W: StableHasherResult>(&self, |
| hcx: &mut StableHashingContext<'gcx>, |
| 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)] |
| pub struct Destructor { |
| /// The def-id of the destructor method |
| pub did: DefId, |
| } |
| |
| bitflags! { |
| pub struct AdtFlags: u32 { |
| const NO_ADT_FLAGS = 0; |
| const IS_ENUM = 1 << 0; |
| const IS_PHANTOM_DATA = 1 << 1; |
| const IS_FUNDAMENTAL = 1 << 2; |
| const IS_UNION = 1 << 3; |
| const IS_BOX = 1 << 4; |
| } |
| } |
| |
| #[derive(Debug)] |
| pub struct VariantDef { |
| /// The variant's DefId. If this is a tuple-like struct, |
| /// this is the DefId of the struct's ctor. |
| pub did: DefId, |
| pub name: Name, // struct's name if this is a struct |
| pub discr: VariantDiscr, |
| pub fields: Vec<FieldDef>, |
| pub ctor_kind: CtorKind, |
| } |
| |
| #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)] |
| 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(usize), |
| } |
| |
| #[derive(Debug)] |
| pub struct FieldDef { |
| pub did: DefId, |
| pub name: Name, |
| 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 { |
| pub did: DefId, |
| pub variants: Vec<VariantDef>, |
| flags: AdtFlags, |
| pub repr: ReprOptions, |
| } |
| |
| impl PartialEq for AdtDef { |
| // AdtDef are always interned and this is part of TyS equality |
| #[inline] |
| fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ } |
| } |
| |
| 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> serialize::UseSpecializedEncodable for &'tcx AdtDef { |
| fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| self.did.encode(s) |
| } |
| } |
| |
| impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {} |
| |
| |
| impl<'gcx> HashStable<StableHashingContext<'gcx>> for AdtDef { |
| fn hash_stable<W: StableHasherResult>(&self, |
| hcx: &mut StableHashingContext<'gcx>, |
| hasher: &mut StableHasher<W>) { |
| let ty::AdtDef { |
| did, |
| ref variants, |
| ref flags, |
| ref repr, |
| } = *self; |
| |
| did.hash_stable(hcx, hasher); |
| variants.hash_stable(hcx, hasher); |
| flags.hash_stable(hcx, hasher); |
| repr.hash_stable(hcx, hasher); |
| } |
| } |
| |
| #[derive(Copy, Clone, Debug, Eq, PartialEq)] |
| pub enum AdtKind { Struct, Union, Enum } |
| |
| bitflags! { |
| #[derive(RustcEncodable, RustcDecodable, Default)] |
| pub struct ReprFlags: u8 { |
| const IS_C = 1 << 0; |
| const IS_PACKED = 1 << 1; |
| const IS_SIMD = 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_PACKED.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, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)] |
| pub struct ReprOptions { |
| pub int: Option<attr::IntType>, |
| pub align: u32, |
| pub flags: ReprFlags, |
| } |
| |
| impl_stable_hash_for!(struct ReprOptions { |
| align, |
| 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 = 0; |
| for attr in tcx.get_attrs(did).iter() { |
| for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) { |
| flags.insert(match r { |
| attr::ReprExtern => ReprFlags::IS_C, |
| attr::ReprPacked => ReprFlags::IS_PACKED, |
| attr::ReprSimd => ReprFlags::IS_SIMD, |
| attr::ReprInt(i) => { |
| size = Some(i); |
| ReprFlags::empty() |
| }, |
| attr::ReprAlign(align) => { |
| max_align = cmp::max(align, max_align); |
| ReprFlags::empty() |
| }, |
| }); |
| } |
| } |
| |
| // FIXME(eddyb) This is deprecated and should be removed. |
| if tcx.has_attr(did, "simd") { |
| flags.insert(ReprFlags::IS_SIMD); |
| } |
| |
| // This is here instead of layout because the choice must make it into metadata. |
| if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) { |
| flags.insert(ReprFlags::IS_LINEAR); |
| } |
| ReprOptions { int: size, align: max_align, 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.flags.contains(ReprFlags::IS_PACKED) } |
| #[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::Is)) |
| } |
| |
| /// 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() |
| } |
| } |
| |
| impl<'a, 'gcx, 'tcx> AdtDef { |
| fn new(tcx: TyCtxt, |
| did: DefId, |
| kind: AdtKind, |
| variants: Vec<VariantDef>, |
| repr: ReprOptions) -> Self { |
| let mut flags = AdtFlags::NO_ADT_FLAGS; |
| let attrs = tcx.get_attrs(did); |
| if attr::contains_name(&attrs, "fundamental") { |
| flags = flags | AdtFlags::IS_FUNDAMENTAL; |
| } |
| if Some(did) == tcx.lang_items().phantom_data() { |
| flags = flags | AdtFlags::IS_PHANTOM_DATA; |
| } |
| if Some(did) == tcx.lang_items().owned_box() { |
| flags = flags | AdtFlags::IS_BOX; |
| } |
| match kind { |
| AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM, |
| AdtKind::Union => flags = flags | AdtFlags::IS_UNION, |
| AdtKind::Struct => {} |
| } |
| AdtDef { |
| did, |
| variants, |
| flags, |
| repr, |
| } |
| } |
| |
| #[inline] |
| pub fn is_struct(&self) -> bool { |
| !self.is_union() && !self.is_enum() |
| } |
| |
| #[inline] |
| pub fn is_union(&self) -> bool { |
| self.flags.intersects(AdtFlags::IS_UNION) |
| } |
| |
| #[inline] |
| pub fn is_enum(&self) -> bool { |
| self.flags.intersects(AdtFlags::IS_ENUM) |
| } |
| |
| /// Returns the kind of the ADT - Struct or Enum. |
| #[inline] |
| pub fn adt_kind(&self) -> AdtKind { |
| if self.is_enum() { |
| AdtKind::Enum |
| } else if self.is_union() { |
| AdtKind::Union |
| } else { |
| AdtKind::Struct |
| } |
| } |
| |
| pub fn descr(&self) -> &'static str { |
| match self.adt_kind() { |
| AdtKind::Struct => "struct", |
| AdtKind::Union => "union", |
| AdtKind::Enum => "enum", |
| } |
| } |
| |
| pub fn variant_descr(&self) -> &'static str { |
| match self.adt_kind() { |
| AdtKind::Struct => "struct", |
| AdtKind::Union => "union", |
| AdtKind::Enum => "variant", |
| } |
| } |
| |
| /// Returns whether this type is #[fundamental] for the purposes |
| /// of coherence checking. |
| #[inline] |
| pub fn is_fundamental(&self) -> bool { |
| self.flags.intersects(AdtFlags::IS_FUNDAMENTAL) |
| } |
| |
| /// Returns true if this is PhantomData<T>. |
| #[inline] |
| pub fn is_phantom_data(&self) -> bool { |
| self.flags.intersects(AdtFlags::IS_PHANTOM_DATA) |
| } |
| |
| /// Returns true if this is Box<T>. |
| #[inline] |
| pub fn is_box(&self) -> bool { |
| self.flags.intersects(AdtFlags::IS_BOX) |
| } |
| |
| /// Returns whether this type has a destructor. |
| pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool { |
| self.destructor(tcx).is_some() |
| } |
| |
| /// Asserts this is a struct and returns the struct's unique |
| /// variant. |
| pub fn struct_variant(&self) -> &VariantDef { |
| assert!(!self.is_enum()); |
| &self.variants[0] |
| } |
| |
| #[inline] |
| pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> { |
| tcx.predicates_of(self.did) |
| } |
| |
| /// Returns an iterator over all fields contained |
| /// by this ADT. |
| #[inline] |
| pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> { |
| self.variants.iter().flat_map(|v| v.fields.iter()) |
| } |
| |
| #[inline] |
| pub fn is_univariant(&self) -> bool { |
| self.variants.len() == 1 |
| } |
| |
| pub fn is_payloadfree(&self) -> bool { |
| !self.variants.is_empty() && |
| self.variants.iter().all(|v| v.fields.is_empty()) |
| } |
| |
| pub fn variant_with_id(&self, vid: DefId) -> &VariantDef { |
| self.variants |
| .iter() |
| .find(|v| v.did == vid) |
| .expect("variant_with_id: unknown variant") |
| } |
| |
| pub fn variant_index_with_id(&self, vid: DefId) -> usize { |
| self.variants |
| .iter() |
| .position(|v| v.did == vid) |
| .expect("variant_index_with_id: unknown variant") |
| } |
| |
| pub fn variant_of_def(&self, def: Def) -> &VariantDef { |
| match def { |
| Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid), |
| Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) | |
| Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.struct_variant(), |
| _ => bug!("unexpected def {:?} in variant_of_def", def) |
| } |
| } |
| |
| #[inline] |
| pub fn discriminants(&'a self, tcx: TyCtxt<'a, 'gcx, 'tcx>) |
| -> impl Iterator<Item=ConstInt> + 'a { |
| let param_env = ParamEnv::empty(traits::Reveal::UserFacing); |
| let repr_type = self.repr.discr_type(); |
| let initial = repr_type.initial_discriminant(tcx.global_tcx()); |
| let mut prev_discr = None::<ConstInt>; |
| self.variants.iter().map(move |v| { |
| let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr()); |
| if let VariantDiscr::Explicit(expr_did) = v.discr { |
| let substs = Substs::identity_for_item(tcx.global_tcx(), expr_did); |
| match tcx.const_eval(param_env.and((expr_did, substs))) { |
| Ok(&ty::Const { val: ConstVal::Integral(v), .. }) => { |
| discr = v; |
| } |
| err => { |
| if !expr_did.is_local() { |
| span_bug!(tcx.def_span(expr_did), |
| "variant discriminant evaluation succeeded \ |
| in its crate but failed locally: {:?}", err); |
| } |
| } |
| } |
| } |
| prev_discr = Some(discr); |
| |
| discr |
| }) |
| } |
| |
| /// Compute 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. |
| pub fn discriminant_for_variant(&self, |
| tcx: TyCtxt<'a, 'gcx, 'tcx>, |
| variant_index: usize) |
| -> ConstInt { |
| let param_env = ParamEnv::empty(traits::Reveal::UserFacing); |
| let repr_type = self.repr.discr_type(); |
| let mut explicit_value = repr_type.initial_discriminant(tcx.global_tcx()); |
| let mut explicit_index = variant_index; |
| loop { |
| match self.variants[explicit_index].discr { |
| ty::VariantDiscr::Relative(0) => break, |
| ty::VariantDiscr::Relative(distance) => { |
| explicit_index -= distance; |
| } |
| ty::VariantDiscr::Explicit(expr_did) => { |
| let substs = Substs::identity_for_item(tcx.global_tcx(), expr_did); |
| match tcx.const_eval(param_env.and((expr_did, substs))) { |
| Ok(&ty::Const { val: ConstVal::Integral(v), .. }) => { |
| explicit_value = v; |
| break; |
| } |
| err => { |
| if !expr_did.is_local() { |
| span_bug!(tcx.def_span(expr_did), |
| "variant discriminant evaluation succeeded \ |
| in its crate but failed locally: {:?}", err); |
| } |
| if explicit_index == 0 { |
| break; |
| } |
| explicit_index -= 1; |
| } |
| } |
| } |
| } |
| } |
| let discr = explicit_value.to_u128_unchecked() |
| .wrapping_add((variant_index - explicit_index) as u128); |
| match repr_type { |
| attr::UnsignedInt(ty) => { |
| ConstInt::new_unsigned_truncating(discr, ty, |
| tcx.sess.target.usize_ty) |
| } |
| attr::SignedInt(ty) => { |
| ConstInt::new_signed_truncating(discr as i128, ty, |
| tcx.sess.target.isize_ty) |
| } |
| } |
| } |
| |
| pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, '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<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] { |
| match queries::adt_sized_constraint::try_get(tcx, DUMMY_SP, self.did) { |
| Ok(tys) => tys, |
| Err(mut bug) => { |
| debug!("adt_sized_constraint: {:?} is recursive", self); |
| // This should be reported as an error by `check_representable`. |
| // |
| // Consider the type as Sized in the meanwhile to avoid |
| // further errors. Delay our `bug` diagnostic here to get |
| // emitted later as well in case we accidentally otherwise don't |
| // emit an error. |
| bug.delay_as_bug(); |
| tcx.intern_type_list(&[tcx.types.err]) |
| } |
| } |
| } |
| |
| fn sized_constraint_for_ty(&self, |
| tcx: TyCtxt<'a, 'tcx, 'tcx>, |
| ty: Ty<'tcx>) |
| -> Vec<Ty<'tcx>> { |
| let result = match ty.sty { |
| TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) | |
| TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) | |
| TyArray(..) | TyClosure(..) | TyGenerator(..) | TyNever => { |
| vec![] |
| } |
| |
| TyStr | TyDynamic(..) | TySlice(_) | TyError => { |
| // these are never sized - return the target type |
| vec![ty] |
| } |
| |
| TyTuple(ref tys, _) => { |
| match tys.last() { |
| None => vec![], |
| Some(ty) => self.sized_constraint_for_ty(tcx, ty) |
| } |
| } |
| |
| TyAdt(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() |
| } |
| |
| TyProjection(..) | TyAnon(..) => { |
| // must calculate explicitly. |
| // FIXME: consider special-casing always-Sized projections |
| vec![ty] |
| } |
| |
| TyParam(..) => { |
| // 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(TraitRef { |
| def_id: sized_trait, |
| substs: tcx.mk_substs_trait(ty, &[]) |
| }).to_predicate(); |
| let predicates = tcx.predicates_of(self.did).predicates; |
| if predicates.into_iter().any(|p| p == sized_predicate) { |
| vec![] |
| } else { |
| vec![ty] |
| } |
| } |
| |
| TyInfer(..) => { |
| bug!("unexpected type `{:?}` in sized_constraint_for_ty", |
| ty) |
| } |
| }; |
| debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result); |
| result |
| } |
| } |
| |
| impl<'a, 'gcx, 'tcx> VariantDef { |
| #[inline] |
| pub fn find_field_named(&self, name: ast::Name) -> Option<&FieldDef> { |
| self.index_of_field_named(name).map(|index| &self.fields[index]) |
| } |
| |
| pub fn index_of_field_named(&self, name: ast::Name) -> Option<usize> { |
| if let Some(index) = self.fields.iter().position(|f| f.name == name) { |
| return Some(index); |
| } |
| let mut ident = name.to_ident(); |
| while ident.ctxt != SyntaxContext::empty() { |
| ident.ctxt.remove_mark(); |
| if let Some(field) = self.fields.iter().position(|f| f.name.to_ident() == ident) { |
| return Some(field); |
| } |
| } |
| None |
| } |
| |
| #[inline] |
| pub fn field_named(&self, name: ast::Name) -> &FieldDef { |
| self.find_field_named(name).unwrap() |
| } |
| } |
| |
| impl<'a, 'gcx, 'tcx> FieldDef { |
| pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> { |
| tcx.type_of(self.did).subst(tcx, subst) |
| } |
| } |
| |
| #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)] |
| 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<'a, 'tcx> ClosureKind { |
| pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId { |
| match *self { |
| ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem), |
| ClosureKind::FnMut => { |
| tcx.require_lang_item(FnMutTraitLangItem) |
| } |
| ClosureKind::FnOnce => { |
| tcx.require_lang_item(FnOnceTraitLangItem) |
| } |
| } |
| } |
| |
| /// 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, |
| } |
| } |
| } |
| |
| 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) -> AccIntoIter<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(); |
| } |
| } |
| } |
| } |
| |
| #[derive(Copy, Clone, Debug, PartialEq, Eq)] |
| pub enum LvaluePreference { |
| PreferMutLvalue, |
| NoPreference |
| } |
| |
| impl LvaluePreference { |
| pub fn from_mutbl(m: hir::Mutability) -> Self { |
| match m { |
| hir::MutMutable => PreferMutLvalue, |
| hir::MutImmutable => NoPreference, |
| } |
| } |
| } |
| |
| 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<'gcx> { |
| Owned(Rc<[ast::Attribute]>), |
| Borrowed(&'gcx [ast::Attribute]) |
| } |
| |
| impl<'gcx> ::std::ops::Deref for Attributes<'gcx> { |
| type Target = [ast::Attribute]; |
| |
| fn deref(&self) -> &[ast::Attribute] { |
| match self { |
| &Attributes::Owned(ref data) => &data, |
| &Attributes::Borrowed(data) => data |
| } |
| } |
| } |
| |
| impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> { |
| pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> { |
| self.typeck_tables_of(self.hir.body_owner_def_id(body)) |
| } |
| |
| /// Returns an iterator of the def-ids 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> + 'a { |
| self.hir.krate() |
| .body_ids |
| .iter() |
| .map(move |&body_id| self.hir.body_owner_def_id(body_id)) |
| } |
| |
| pub fn expr_span(self, id: NodeId) -> Span { |
| match self.hir.find(id) { |
| Some(hir_map::NodeExpr(e)) => { |
| e.span |
| } |
| Some(f) => { |
| bug!("Node id {} is not an expr: {:?}", id, f); |
| } |
| None => { |
| bug!("Node id {} is not present in the node map", id); |
| } |
| } |
| } |
| |
| pub fn expr_is_lval(self, expr: &hir::Expr) -> bool { |
| match expr.node { |
| hir::ExprPath(hir::QPath::Resolved(_, ref path)) => { |
| match path.def { |
| Def::Local(..) | Def::Upvar(..) | Def::Static(..) | Def::Err => true, |
| _ => false, |
| } |
| } |
| |
| hir::ExprType(ref e, _) => { |
| self.expr_is_lval(e) |
| } |
| |
| hir::ExprUnary(hir::UnDeref, _) | |
| hir::ExprField(..) | |
| hir::ExprTupField(..) | |
| hir::ExprIndex(..) => { |
| true |
| } |
| |
| // Partially qualified paths in expressions can only legally |
| // refer to associated items which are always rvalues. |
| hir::ExprPath(hir::QPath::TypeRelative(..)) | |
| |
| hir::ExprCall(..) | |
| hir::ExprMethodCall(..) | |
| hir::ExprStruct(..) | |
| hir::ExprTup(..) | |
| hir::ExprIf(..) | |
| hir::ExprMatch(..) | |
| hir::ExprClosure(..) | |
| hir::ExprBlock(..) | |
| hir::ExprRepeat(..) | |
| hir::ExprArray(..) | |
| hir::ExprBreak(..) | |
| hir::ExprAgain(..) | |
| hir::ExprRet(..) | |
| hir::ExprWhile(..) | |
| hir::ExprLoop(..) | |
| hir::ExprAssign(..) | |
| hir::ExprInlineAsm(..) | |
| hir::ExprAssignOp(..) | |
| hir::ExprLit(_) | |
| hir::ExprUnary(..) | |
| hir::ExprBox(..) | |
| hir::ExprAddrOf(..) | |
| hir::ExprBinary(..) | |
| hir::ExprYield(..) | |
| hir::ExprCast(..) => { |
| false |
| } |
| } |
| } |
| |
| pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> { |
| self.associated_items(id) |
| .filter(|item| item.kind == AssociatedKind::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<AssociatedItem> { |
| let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) { |
| match self.hir.get(node_id) { |
| hir_map::NodeTraitItem(_) | hir_map::NodeImplItem(_) => true, |
| _ => false, |
| } |
| } else { |
| match self.describe_def(def_id).expect("no def for def-id") { |
| Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => 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) |
| -> AssociatedItem { |
| let def_id = self.hir.local_def_id(trait_item_ref.id.node_id); |
| let (kind, has_self) = match trait_item_ref.kind { |
| hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false), |
| hir::AssociatedItemKind::Method { has_self } => { |
| (ty::AssociatedKind::Method, has_self) |
| } |
| hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false), |
| }; |
| |
| AssociatedItem { |
| name: trait_item_ref.name, |
| kind, |
| // Visibility of trait items is inherited from their traits. |
| vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_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) |
| -> AssociatedItem { |
| let def_id = self.hir.local_def_id(impl_item_ref.id.node_id); |
| let (kind, has_self) = match impl_item_ref.kind { |
| hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false), |
| hir::AssociatedItemKind::Method { has_self } => { |
| (ty::AssociatedKind::Method, has_self) |
| } |
| hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false), |
| }; |
| |
| ty::AssociatedItem { |
| name: impl_item_ref.name, |
| kind, |
| // Visibility of trait impl items doesn't matter. |
| vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self), |
| defaultness: impl_item_ref.defaultness, |
| def_id, |
| container: ImplContainer(parent_def_id), |
| method_has_self_argument: has_self |
| } |
| } |
| |
| #[inline] // FIXME(#35870) Avoid closures being unexported due to impl Trait. |
| pub fn associated_items(self, def_id: DefId) |
| -> impl Iterator<Item = ty::AssociatedItem> + 'a { |
| let def_ids = self.associated_item_def_ids(def_id); |
| (0..def_ids.len()).map(move |i| self.associated_item(def_ids[i])) |
| } |
| |
| /// Returns true if the impls are the same polarity and are implementing |
| /// a trait which contains no items |
| pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool { |
| if !self.sess.features.borrow().overlapping_marker_traits { |
| return false; |
| } |
| 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 |
| } |
| |
| // Returns `ty::VariantDef` if `def` refers to a struct, |
| // or variant or their constructors, panics otherwise. |
| pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef { |
| match def { |
| Def::Variant(did) | Def::VariantCtor(did, ..) => { |
| let enum_did = self.parent_def_id(did).unwrap(); |
| self.adt_def(enum_did).variant_with_id(did) |
| } |
| Def::Struct(did) | Def::Union(did) => { |
| self.adt_def(did).struct_variant() |
| } |
| Def::StructCtor(ctor_did, ..) => { |
| let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent"); |
| self.adt_def(did).struct_variant() |
| } |
| _ => bug!("expect_variant_def used with unexpected def {:?}", def) |
| } |
| } |
| |
| /// Given a `VariantDef`, returns the def-id of the `AdtDef` of which it is a part. |
| pub fn adt_def_id_of_variant(self, variant_def: &'tcx VariantDef) -> DefId { |
| let def_key = self.def_key(variant_def.did); |
| match def_key.disambiguated_data.data { |
| // for enum variants and tuple structs, the def-id of the ADT itself |
| // is the *parent* of the variant |
| DefPathData::EnumVariant(..) | DefPathData::StructCtor => |
| DefId { krate: variant_def.did.krate, index: def_key.parent.unwrap() }, |
| |
| // otherwise, for structs and unions, they share a def-id |
| _ => variant_def.did, |
| } |
| } |
| |
| pub fn item_name(self, id: DefId) -> InternedString { |
| if let Some(id) = self.hir.as_local_node_id(id) { |
| self.hir.name(id).as_str() |
| } else if id.index == CRATE_DEF_INDEX { |
| self.original_crate_name(id.krate).as_str() |
| } else { |
| let def_key = self.def_key(id); |
| // The name of a StructCtor is that of its struct parent. |
| if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data { |
| self.item_name(DefId { |
| krate: id.krate, |
| index: def_key.parent.unwrap() |
| }) |
| } else { |
| def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| { |
| bug!("item_name: no name for {:?}", self.def_path(id)); |
| }) |
| } |
| } |
| } |
| |
| /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair. |
| pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>) |
| -> &'gcx Mir<'gcx> |
| { |
| match instance { |
| ty::InstanceDef::Item(did) => { |
| self.optimized_mir(did) |
| } |
| ty::InstanceDef::Intrinsic(..) | |
| ty::InstanceDef::FnPtrShim(..) | |
| ty::InstanceDef::Virtual(..) | |
| ty::InstanceDef::ClosureOnceShim { .. } | |
| ty::InstanceDef::DropGlue(..) | |
| ty::InstanceDef::CloneShim(..) => { |
| self.mir_shims(instance) |
| } |
| } |
| } |
| |
| /// Given the DefId of an item, returns its MIR, borrowed immutably. |
| /// Returns None if there is no MIR for the DefId |
| pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> { |
| if self.is_mir_available(did) { |
| Some(self.optimized_mir(did)) |
| } else { |
| None |
| } |
| } |
| |
| /// Get the attributes of a definition. |
| pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> { |
| if let Some(id) = self.hir.as_local_node_id(did) { |
| Attributes::Borrowed(self.hir.attrs(id)) |
| } else { |
| Attributes::Owned(self.item_attrs(did)) |
| } |
| } |
| |
| /// Determine whether an item is annotated with an attribute |
| pub fn has_attr(self, did: DefId, attr: &str) -> bool { |
| self.get_attrs(did).iter().any(|item| item.check_name(attr)) |
| } |
| |
| pub fn trait_has_default_impl(self, trait_def_id: DefId) -> bool { |
| self.trait_def(trait_def_id).has_default_impl |
| } |
| |
| pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> { |
| self.optimized_mir(def_id).generator_layout.as_ref().unwrap() |
| } |
| |
| /// Given the def_id of an impl, return the def_id of the trait it implements. |
| /// If it implements no trait, return `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 def ID describes a method belonging to an impl, return the |
| /// ID of the impl that the method belongs to. Otherwise, return `None`. |
| pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> { |
| let item = if def_id.krate != LOCAL_CRATE { |
| if let Some(Def::Method(_)) = self.describe_def(def_id) { |
| Some(self.associated_item(def_id)) |
| } else { |
| None |
| } |
| } else { |
| self.opt_associated_item(def_id) |
| }; |
| |
| match item { |
| Some(trait_item) => { |
| match trait_item.container { |
| TraitContainer(_) => None, |
| ImplContainer(def_id) => Some(def_id), |
| } |
| } |
| None => None |
| } |
| } |
| |
| /// 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 node_id = self.hir.as_local_node_id(impl_did).unwrap(); |
| Ok(self.hir.span(node_id)) |
| } else { |
| Err(self.crate_name(impl_did.krate)) |
| } |
| } |
| |
| // Hygienically compare 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: Name, def_name: Name, def_parent_def_id: DefId) -> bool { |
| self.adjust(use_name, def_parent_def_id, DUMMY_NODE_ID).0 == def_name.to_ident() |
| } |
| |
| pub fn adjust(self, name: Name, scope: DefId, block: NodeId) -> (Ident, DefId) { |
| self.adjust_ident(name.to_ident(), scope, block) |
| } |
| |
| pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) { |
| let expansion = match scope.krate { |
| LOCAL_CRATE => self.hir.definitions().expansion(scope.index), |
| _ => Mark::root(), |
| }; |
| let scope = match ident.ctxt.adjust(expansion) { |
| Some(macro_def) => self.hir.definitions().macro_def_scope(macro_def), |
| None if block == DUMMY_NODE_ID => DefId::local(CRATE_DEF_INDEX), // Dummy DefId |
| None => self.hir.get_module_parent(block), |
| }; |
| (ident, scope) |
| } |
| } |
| |
| impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> { |
| pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where |
| F: FnOnce(&[hir::Freevar]) -> T, |
| { |
| let def_id = self.hir.local_def_id(fid); |
| match self.freevars(def_id) { |
| None => f(&[]), |
| Some(d) => f(&d), |
| } |
| } |
| } |
| |
| fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) |
| -> AssociatedItem |
| { |
| let id = tcx.hir.as_local_node_id(def_id).unwrap(); |
| let parent_id = tcx.hir.get_parent(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::ItemImpl(.., ref impl_item_refs) => { |
| if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_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::ItemTrait(.., ref trait_item_refs) => { |
| if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_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) |
| } |
| |
| /// 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 TyError, if a type contained itself. The representability |
| /// check should catch this case. |
| fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, |
| def_id: DefId) |
| -> &'tcx [Ty<'tcx>] { |
| let def = tcx.adt_def(def_id); |
| |
| let result = tcx.intern_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)) |
| }).collect::<Vec<_>>()); |
| |
| debug!("adt_sized_constraint: {:?} => {:?}", def, result); |
| |
| result |
| } |
| |
| /// Calculates the dtorck constraint for a type. |
| fn adt_dtorck_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, |
| def_id: DefId) |
| -> DtorckConstraint<'tcx> { |
| let def = tcx.adt_def(def_id); |
| let span = tcx.def_span(def_id); |
| debug!("dtorck_constraint: {:?}", def); |
| |
| if def.is_phantom_data() { |
| let result = DtorckConstraint { |
| outlives: vec![], |
| dtorck_types: vec![ |
| tcx.mk_param_from_def(&tcx.generics_of(def_id).types[0]) |
| ] |
| }; |
| debug!("dtorck_constraint: {:?} => {:?}", def, result); |
| return result; |
| } |
| |
| let mut result = def.all_fields() |
| .map(|field| tcx.type_of(field.did)) |
| .map(|fty| tcx.dtorck_constraint_for_ty(span, fty, 0, fty)) |
| .collect::<Result<DtorckConstraint, ErrorReported>>() |
| .unwrap_or(DtorckConstraint::empty()); |
| result.outlives.extend(tcx.destructor_constraints(def)); |
| result.dedup(); |
| |
| debug!("dtorck_constraint: {:?} => {:?}", def, result); |
| |
| result |
| } |
| |
| fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, |
| def_id: DefId) |
| -> Rc<Vec<DefId>> { |
| let id = tcx.hir.as_local_node_id(def_id).unwrap(); |
| let item = tcx.hir.expect_item(id); |
| let vec: Vec<_> = match item.node { |
| hir::ItemTrait(.., ref trait_item_refs) => { |
| trait_item_refs.iter() |
| .map(|trait_item_ref| trait_item_ref.id) |
| .map(|id| tcx.hir.local_def_id(id.node_id)) |
| .collect() |
| } |
| hir::ItemImpl(.., ref impl_item_refs) => { |
| impl_item_refs.iter() |
| .map(|impl_item_ref| impl_item_ref.id) |
| .map(|id| tcx.hir.local_def_id(id.node_id)) |
| .collect() |
| } |
| _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait") |
| }; |
| Rc::new(vec) |
| } |
| |
| fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span { |
| tcx.hir.span_if_local(def_id).unwrap() |
| } |
| |
| /// If the given def ID describes an item belonging to a trait, |
| /// return the ID of the trait that the trait item belongs to. |
| /// Otherwise, return `None`. |
| fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, 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 |
| } |
| }) |
| } |
| |
| /// See `ParamEnv` struct def'n for details. |
| fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, |
| def_id: DefId) |
| -> ParamEnv<'tcx> { |
| // Compute the bounds on Self and the type parameters. |
| |
| let bounds = tcx.predicates_of(def_id).instantiate_identity(tcx); |
| let predicates = bounds.predicates; |
| |
| // 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); |
| |
| let body_id = tcx.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| { |
| tcx.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_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<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, |
| crate_num: CrateNum) -> Symbol { |
| assert_eq!(crate_num, LOCAL_CRATE); |
| tcx.sess.local_crate_disambiguator() |
| } |
| |
| fn original_crate_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, |
| crate_num: CrateNum) -> Symbol { |
| assert_eq!(crate_num, LOCAL_CRATE); |
| tcx.crate_name.clone() |
| } |
| |
| pub fn provide(providers: &mut ty::maps::Providers) { |
| util::provide(providers); |
| context::provide(providers); |
| erase_regions::provide(providers); |
| *providers = ty::maps::Providers { |
| associated_item, |
| associated_item_def_ids, |
| adt_sized_constraint, |
| adt_dtorck_constraint, |
| def_span, |
| param_env, |
| trait_of_item, |
| crate_disambiguator, |
| original_crate_name, |
| trait_impls_of: trait_def::trait_impls_of_provider, |
| ..*providers |
| }; |
| } |
| |
| pub fn provide_extern(providers: &mut ty::maps::Providers) { |
| *providers = ty::maps::Providers { |
| adt_sized_constraint, |
| adt_dtorck_constraint, |
| trait_impls_of: trait_def::trait_impls_of_provider, |
| param_env, |
| ..*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)] |
| pub struct CrateInherentImpls { |
| pub inherent_impls: DefIdMap<Rc<Vec<DefId>>>, |
| } |
| |
| /// A set of constraints that need to be satisfied in order for |
| /// a type to be valid for destruction. |
| #[derive(Clone, Debug)] |
| pub struct DtorckConstraint<'tcx> { |
| /// Types that are required to be alive in order for this |
| /// type to be valid for destruction. |
| pub outlives: Vec<ty::subst::Kind<'tcx>>, |
| /// Types that could not be resolved: projections and params. |
| pub dtorck_types: Vec<Ty<'tcx>>, |
| } |
| |
| impl<'tcx> FromIterator<DtorckConstraint<'tcx>> for DtorckConstraint<'tcx> |
| { |
| fn from_iter<I: IntoIterator<Item=DtorckConstraint<'tcx>>>(iter: I) -> Self { |
| let mut result = Self::empty(); |
| |
| for constraint in iter { |
| result.outlives.extend(constraint.outlives); |
| result.dtorck_types.extend(constraint.dtorck_types); |
| } |
| |
| result |
| } |
| } |
| |
| |
| impl<'tcx> DtorckConstraint<'tcx> { |
| fn empty() -> DtorckConstraint<'tcx> { |
| DtorckConstraint { |
| outlives: vec![], |
| dtorck_types: vec![] |
| } |
| } |
| |
| fn dedup<'a>(&mut self) { |
| let mut outlives = FxHashSet(); |
| let mut dtorck_types = FxHashSet(); |
| |
| self.outlives.retain(|&val| outlives.replace(val).is_none()); |
| self.dtorck_types.retain(|&val| dtorck_types.replace(val).is_none()); |
| } |
| } |
| |
| #[derive(Clone, PartialEq, Eq, PartialOrd, Ord)] |
| 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 Deref for SymbolName { |
| type Target = str; |
| |
| fn deref(&self) -> &str { &self.name } |
| } |
| |
| impl fmt::Display for SymbolName { |
| fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { |
| fmt::Display::fmt(&self.name, fmt) |
| } |
| } |