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fuchsia / third_party / rust / 1.7.0 / . / src / librustc / middle / ty / mod.rs
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// 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::ImplOrTraitItemId::*;
pub use self::ClosureKind::*;
pub use self::Variance::*;
pub use self::DtorKind::*;
pub use self::ImplOrTraitItemContainer::*;
pub use self::BorrowKind::*;
pub use self::ImplOrTraitItem::*;
pub use self::IntVarValue::*;
pub use self::LvaluePreference::*;
pub use self::fold::TypeFoldable;
use dep_graph::{self, DepNode};
use front::map as ast_map;
use front::map::LinkedPath;
use middle;
use middle::cstore::{self, CrateStore, LOCAL_CRATE};
use middle::def::{self, ExportMap};
use middle::def_id::DefId;
use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
use middle::region::{CodeExtent};
use middle::subst::{self, Subst, Substs, VecPerParamSpace};
use middle::traits;
use middle::ty;
use middle::ty::fold::TypeFolder;
use middle::ty::walk::TypeWalker;
use util::common::MemoizationMap;
use util::nodemap::{NodeMap, NodeSet};
use util::nodemap::FnvHashMap;
use serialize::{Encodable, Encoder, Decodable, Decoder};
use std::borrow::{Borrow, Cow};
use std::cell::Cell;
use std::hash::{Hash, Hasher};
use std::iter;
use std::rc::Rc;
use std::slice;
use std::vec::IntoIter;
use std::collections::{HashMap, HashSet};
use syntax::ast::{self, CrateNum, Name, NodeId};
use syntax::attr::{self, AttrMetaMethods};
use syntax::codemap::{DUMMY_SP, Span};
use syntax::parse::token::InternedString;
use rustc_front::hir;
use rustc_front::hir::{ItemImpl, ItemTrait};
use rustc_front::intravisit::Visitor;
pub use self::sty::{Binder, DebruijnIndex};
pub use self::sty::{BuiltinBound, BuiltinBounds, ExistentialBounds};
pub use self::sty::{BareFnTy, FnSig, PolyFnSig, FnOutput, PolyFnOutput};
pub use self::sty::{ClosureTy, InferTy, ParamTy, ProjectionTy, TraitTy};
pub use self::sty::{ClosureSubsts, TypeAndMut};
pub use self::sty::{TraitRef, TypeVariants, PolyTraitRef};
pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid, SkolemizedRegionVid};
pub use self::sty::BoundRegion::*;
pub use self::sty::FnOutput::*;
pub use self::sty::InferTy::*;
pub use self::sty::Region::*;
pub use self::sty::TypeVariants::*;
pub use self::sty::BuiltinBound::Send as BoundSend;
pub use self::sty::BuiltinBound::Sized as BoundSized;
pub use self::sty::BuiltinBound::Copy as BoundCopy;
pub use self::sty::BuiltinBound::Sync as BoundSync;
pub use self::contents::TypeContents;
pub use self::context::{ctxt, tls};
pub use self::context::{CtxtArenas, Lift, Tables};
pub use self::trait_def::{TraitDef, TraitFlags};
pub mod adjustment;
pub mod cast;
pub mod error;
pub mod fast_reject;
pub mod fold;
pub mod _match;
pub mod maps;
pub mod outlives;
pub mod relate;
pub mod trait_def;
pub mod walk;
pub mod wf;
pub mod util;
mod contents;
mod context;
mod flags;
mod ivar;
mod structural_impls;
mod sty;
pub type Disr = u64;
pub const INITIAL_DISCRIMINANT_VALUE: Disr = 0;
// 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.
pub struct CrateAnalysis<'a> {
pub export_map: ExportMap,
pub access_levels: middle::privacy::AccessLevels,
pub reachable: NodeSet,
pub name: &'a str,
pub glob_map: Option<GlobMap>,
}
#[derive(Copy, Clone)]
pub enum DtorKind {
NoDtor,
TraitDtor(bool)
}
impl DtorKind {
pub fn is_present(&self) -> bool {
match *self {
TraitDtor(..) => true,
_ => false
}
}
pub fn has_drop_flag(&self) -> bool {
match self {
&NoDtor => false,
&TraitDtor(flag) => flag
}
}
}
#[derive(Clone, Copy, PartialEq, Eq, Debug)]
pub enum ImplOrTraitItemContainer {
TraitContainer(DefId),
ImplContainer(DefId),
}
impl ImplOrTraitItemContainer {
pub fn id(&self) -> DefId {
match *self {
TraitContainer(id) => id,
ImplContainer(id) => id,
}
}
}
#[derive(Clone)]
pub enum ImplOrTraitItem<'tcx> {
ConstTraitItem(Rc<AssociatedConst<'tcx>>),
MethodTraitItem(Rc<Method<'tcx>>),
TypeTraitItem(Rc<AssociatedType<'tcx>>),
}
impl<'tcx> ImplOrTraitItem<'tcx> {
fn id(&self) -> ImplOrTraitItemId {
match *self {
ConstTraitItem(ref associated_const) => {
ConstTraitItemId(associated_const.def_id)
}
MethodTraitItem(ref method) => MethodTraitItemId(method.def_id),
TypeTraitItem(ref associated_type) => {
TypeTraitItemId(associated_type.def_id)
}
}
}
pub fn def_id(&self) -> DefId {
match *self {
ConstTraitItem(ref associated_const) => associated_const.def_id,
MethodTraitItem(ref method) => method.def_id,
TypeTraitItem(ref associated_type) => associated_type.def_id,
}
}
pub fn name(&self) -> Name {
match *self {
ConstTraitItem(ref associated_const) => associated_const.name,
MethodTraitItem(ref method) => method.name,
TypeTraitItem(ref associated_type) => associated_type.name,
}
}
pub fn vis(&self) -> hir::Visibility {
match *self {
ConstTraitItem(ref associated_const) => associated_const.vis,
MethodTraitItem(ref method) => method.vis,
TypeTraitItem(ref associated_type) => associated_type.vis,
}
}
pub fn container(&self) -> ImplOrTraitItemContainer {
match *self {
ConstTraitItem(ref associated_const) => associated_const.container,
MethodTraitItem(ref method) => method.container,
TypeTraitItem(ref associated_type) => associated_type.container,
}
}
pub fn as_opt_method(&self) -> Option<Rc<Method<'tcx>>> {
match *self {
MethodTraitItem(ref m) => Some((*m).clone()),
_ => None,
}
}
}
#[derive(Clone, Copy, Debug)]
pub enum ImplOrTraitItemId {
ConstTraitItemId(DefId),
MethodTraitItemId(DefId),
TypeTraitItemId(DefId),
}
impl ImplOrTraitItemId {
pub fn def_id(&self) -> DefId {
match *self {
ConstTraitItemId(def_id) => def_id,
MethodTraitItemId(def_id) => def_id,
TypeTraitItemId(def_id) => def_id,
}
}
}
#[derive(Clone, Debug)]
pub struct Method<'tcx> {
pub name: Name,
pub generics: Generics<'tcx>,
pub predicates: GenericPredicates<'tcx>,
pub fty: BareFnTy<'tcx>,
pub explicit_self: ExplicitSelfCategory,
pub vis: hir::Visibility,
pub def_id: DefId,
pub container: ImplOrTraitItemContainer,
}
impl<'tcx> Method<'tcx> {
pub fn new(name: Name,
generics: ty::Generics<'tcx>,
predicates: GenericPredicates<'tcx>,
fty: BareFnTy<'tcx>,
explicit_self: ExplicitSelfCategory,
vis: hir::Visibility,
def_id: DefId,
container: ImplOrTraitItemContainer)
-> Method<'tcx> {
Method {
name: name,
generics: generics,
predicates: predicates,
fty: fty,
explicit_self: explicit_self,
vis: vis,
def_id: def_id,
container: container,
}
}
pub fn container_id(&self) -> DefId {
match self.container {
TraitContainer(id) => id,
ImplContainer(id) => id,
}
}
}
impl<'tcx> PartialEq for Method<'tcx> {
#[inline]
fn eq(&self, other: &Self) -> bool { self.def_id == other.def_id }
}
impl<'tcx> Eq for Method<'tcx> {}
impl<'tcx> Hash for Method<'tcx> {
#[inline]
fn hash<H: Hasher>(&self, s: &mut H) {
self.def_id.hash(s)
}
}
#[derive(Clone, Copy, Debug)]
pub struct AssociatedConst<'tcx> {
pub name: Name,
pub ty: Ty<'tcx>,
pub vis: hir::Visibility,
pub def_id: DefId,
pub container: ImplOrTraitItemContainer,
pub has_value: bool
}
#[derive(Clone, Copy, Debug)]
pub struct AssociatedType<'tcx> {
pub name: Name,
pub ty: Option<Ty<'tcx>>,
pub vis: hir::Visibility,
pub def_id: DefId,
pub container: ImplOrTraitItemContainer,
}
#[derive(Clone, PartialEq, RustcDecodable, RustcEncodable)]
pub struct ItemVariances {
pub types: VecPerParamSpace<Variance>,
pub regions: VecPerParamSpace<Variance>,
}
#[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
}
#[derive(Clone, Copy, Debug)]
pub struct MethodCallee<'tcx> {
/// Impl method ID, for inherent methods, or trait method ID, otherwise.
pub def_id: DefId,
pub ty: Ty<'tcx>,
pub substs: &'tcx subst::Substs<'tcx>
}
/// With method calls, we store some extra information in
/// side tables (i.e method_map). We use
/// MethodCall as a key to index into these tables instead of
/// just directly using the expression's NodeId. The reason
/// for this being that we may apply adjustments (coercions)
/// with the resulting expression also needing to use the
/// side tables. The problem with this is that we don't
/// assign a separate NodeId to this new expression
/// and so it would clash with the base expression if both
/// needed to add to the side tables. Thus to disambiguate
/// we also keep track of whether there's an adjustment in
/// our key.
#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
pub struct MethodCall {
pub expr_id: NodeId,
pub autoderef: u32
}
impl MethodCall {
pub fn expr(id: NodeId) -> MethodCall {
MethodCall {
expr_id: id,
autoderef: 0
}
}
pub fn autoderef(expr_id: NodeId, autoderef: u32) -> MethodCall {
MethodCall {
expr_id: expr_id,
autoderef: 1 + autoderef
}
}
}
// maps from an expression id that corresponds to a method call to the details
// of the method to be invoked
pub type MethodMap<'tcx> = FnvHashMap<MethodCall, MethodCallee<'tcx>>;
// 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,
}
/// A restriction that certain types must be the same size. The use of
/// `transmute` gives rise to these restrictions. These generally
/// cannot be checked until trans; therefore, each call to `transmute`
/// will push one or more such restriction into the
/// `transmute_restrictions` vector during `intrinsicck`. They are
/// then checked during `trans` by the fn `check_intrinsics`.
#[derive(Copy, Clone)]
pub struct TransmuteRestriction<'tcx> {
/// The span whence the restriction comes.
pub span: Span,
/// The type being transmuted from.
pub original_from: Ty<'tcx>,
/// The type being transmuted to.
pub original_to: Ty<'tcx>,
/// The type being transmuted from, with all type parameters
/// substituted for an arbitrary representative. Not to be shown
/// to the end user.
pub substituted_from: Ty<'tcx>,
/// The type being transmuted to, with all type parameters
/// substituted for an arbitrary representative. Not to be shown
/// to the end user.
pub substituted_to: Ty<'tcx>,
/// NodeId of the transmute intrinsic.
pub id: NodeId,
}
/// Describes the fragment-state associated with a NodeId.
///
/// Currently only unfragmented paths have entries in the table,
/// but longer-term this enum is expected to expand to also
/// include data for fragmented paths.
#[derive(Copy, Clone, Debug)]
pub enum FragmentInfo {
Moved { var: NodeId, move_expr: NodeId },
Assigned { var: NodeId, assign_expr: NodeId, assignee_id: NodeId },
}
// 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! {
flags 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_EARLY_BOUND = 1 << 4,
const HAS_FREE_REGIONS = 1 << 5,
const HAS_TY_ERR = 1 << 6,
const HAS_PROJECTION = 1 << 7,
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_LOCAL_NAMES = 1 << 9,
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_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,
// Caches for type_is_sized, type_moves_by_default
const SIZEDNESS_CACHED = 1 << 16,
const IS_SIZED = 1 << 17,
const MOVENESS_CACHED = 1 << 18,
const MOVES_BY_DEFAULT = 1 << 19,
}
}
pub struct TyS<'tcx> {
pub sty: TypeVariants<'tcx>,
pub flags: Cell<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)
}
}
pub type Ty<'tcx> = &'tcx TyS<'tcx>;
impl<'tcx> Encodable for Ty<'tcx> {
fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
cstore::tls::with_encoding_context(s, |ecx, rbml_w| {
ecx.encode_ty(rbml_w, *self);
Ok(())
})
}
}
impl<'tcx> Decodable for Ty<'tcx> {
fn decode<D: Decoder>(d: &mut D) -> Result<Ty<'tcx>, D::Error> {
cstore::tls::with_decoding_context(d, |dcx, rbml_r| {
Ok(dcx.decode_ty(rbml_r))
})
}
}
/// 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)]
pub struct UpvarId {
pub var_id: NodeId,
pub closure_expr_id: NodeId,
}
#[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 you 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)]
pub enum UpvarCapture {
/// 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),
}
#[derive(PartialEq, Clone, Copy)]
pub struct UpvarBorrow {
/// 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,
}
pub type UpvarCaptureMap = FnvHashMap<UpvarId, UpvarCapture>;
#[derive(Copy, Clone)]
pub struct ClosureUpvar<'tcx> {
pub def: def::Def,
pub span: Span,
pub ty: Ty<'tcx>,
}
#[derive(Clone, Copy, PartialEq)]
pub enum IntVarValue {
IntType(ast::IntTy),
UintType(ast::UintTy),
}
/// Default region to use for the bound of objects that are
/// supplied as the value for this type parameter. This is derived
/// from `T:'a` annotations appearing in the type definition. If
/// this is `None`, then the default is inherited from the
/// surrounding context. See RFC #599 for details.
#[derive(Copy, Clone)]
pub enum ObjectLifetimeDefault {
/// Require an explicit annotation. Occurs when multiple
/// `T:'a` constraints are found.
Ambiguous,
/// Use the base default, typically 'static, but in a fn body it is a fresh variable
BaseDefault,
/// Use the given region as the default.
Specific(Region),
}
#[derive(Clone)]
pub struct TypeParameterDef<'tcx> {
pub name: Name,
pub def_id: DefId,
pub space: subst::ParamSpace,
pub index: u32,
pub default_def_id: DefId, // for use in error reporing about defaults
pub default: Option<Ty<'tcx>>,
pub object_lifetime_default: ObjectLifetimeDefault,
}
#[derive(Clone)]
pub struct RegionParameterDef {
pub name: Name,
pub def_id: DefId,
pub space: subst::ParamSpace,
pub index: u32,
pub bounds: Vec<ty::Region>,
}
impl RegionParameterDef {
pub fn to_early_bound_region(&self) -> ty::Region {
ty::ReEarlyBound(ty::EarlyBoundRegion {
space: self.space,
index: self.index,
name: self.name,
})
}
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.
#[derive(Clone, Debug)]
pub struct Generics<'tcx> {
pub types: VecPerParamSpace<TypeParameterDef<'tcx>>,
pub regions: VecPerParamSpace<RegionParameterDef>,
}
impl<'tcx> Generics<'tcx> {
pub fn empty() -> Generics<'tcx> {
Generics {
types: VecPerParamSpace::empty(),
regions: VecPerParamSpace::empty(),
}
}
pub fn is_empty(&self) -> bool {
self.types.is_empty() && self.regions.is_empty()
}
pub fn has_type_params(&self, space: subst::ParamSpace) -> bool {
!self.types.is_empty_in(space)
}
pub fn has_region_params(&self, space: subst::ParamSpace) -> bool {
!self.regions.is_empty_in(space)
}
}
/// Bounds on generics.
#[derive(Clone)]
pub struct GenericPredicates<'tcx> {
pub predicates: VecPerParamSpace<Predicate<'tcx>>,
}
impl<'tcx> GenericPredicates<'tcx> {
pub fn empty() -> GenericPredicates<'tcx> {
GenericPredicates {
predicates: VecPerParamSpace::empty(),
}
}
pub fn instantiate(&self, tcx: &ctxt<'tcx>, substs: &Substs<'tcx>)
-> InstantiatedPredicates<'tcx> {
InstantiatedPredicates {
predicates: self.predicates.subst(tcx, substs),
}
}
pub fn instantiate_supertrait(&self,
tcx: &ctxt<'tcx>,
poly_trait_ref: &ty::PolyTraitRef<'tcx>)
-> InstantiatedPredicates<'tcx>
{
InstantiatedPredicates {
predicates: self.predicates.map(|pred| pred.subst_supertrait(tcx, poly_trait_ref))
}
}
}
#[derive(Clone, PartialEq, Eq, Hash)]
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 parameters in the `TypeSpace`.
Trait(PolyTraitPredicate<'tcx>),
/// where `T1 == T2`.
Equate(PolyEquatePredicate<'tcx>),
/// where 'a : 'b
RegionOutlives(PolyRegionOutlivesPredicate),
/// 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),
}
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: &ctxt<'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::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),
}
}
}
#[derive(Clone, PartialEq, Eq, Hash)]
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(&self) -> &[Ty<'tcx>] {
self.trait_ref.substs.types.as_slice()
}
pub fn self_ty(&self) -> Ty<'tcx> {
self.trait_ref.self_ty()
}
}
impl<'tcx> PolyTraitPredicate<'tcx> {
pub fn def_id(&self) -> DefId {
self.0.def_id()
}
}
#[derive(Clone, PartialEq, Eq, Hash, Debug)]
pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
#[derive(Clone, PartialEq, Eq, Hash, Debug)]
pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
pub type PolyRegionOutlivesPredicate = PolyOutlivesPredicate<ty::Region, ty::Region>;
pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region>;
/// 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(Clone, PartialEq, Eq, Hash)]
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 item_name(&self) -> Name {
self.0.projection_ty.item_name // safe to skip the binder to access a name
}
pub fn sort_key(&self) -> (DefId, Name) {
self.0.projection_ty.sort_key()
}
}
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.clone())
}
}
impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
fn to_poly_trait_ref(&self) -> 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.clone())
}
}
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 {
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.0.trait_ref.substs.types.as_slice().to_vec()
}
ty::Predicate::Equate(ty::Binder(ref data)) => {
vec![data.0, data.1]
}
ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
vec![data.0]
}
ty::Predicate::RegionOutlives(..) => {
vec![]
}
ty::Predicate::Projection(ref data) => {
let trait_inputs = data.0.projection_ty.trait_ref.substs.types.as_slice();
trait_inputs.iter()
.cloned()
.chain(Some(data.0.ty))
.collect()
}
ty::Predicate::WellFormed(data) => {
vec![data]
}
ty::Predicate::ObjectSafe(_trait_def_id) => {
vec![]
}
};
// 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::RegionOutlives(..) |
Predicate::WellFormed(..) |
Predicate::ObjectSafe(..) |
Predicate::TypeOutlives(..) => {
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: VecPerParamSpace<Predicate<'tcx>>,
}
impl<'tcx> InstantiatedPredicates<'tcx> {
pub fn empty() -> InstantiatedPredicates<'tcx> {
InstantiatedPredicates { predicates: VecPerParamSpace::empty() }
}
pub fn is_empty(&self) -> bool {
self.predicates.is_empty()
}
}
impl<'tcx> TraitRef<'tcx> {
pub fn new(def_id: DefId, substs: &'tcx Substs<'tcx>) -> TraitRef<'tcx> {
TraitRef { def_id: def_id, substs: substs }
}
pub fn self_ty(&self) -> Ty<'tcx> {
self.substs.self_ty().unwrap()
}
pub fn input_types(&self) -> &[Ty<'tcx>] {
// Select only the "input types" from a trait-reference. For
// now this is all the types that appear in the
// trait-reference, but it should eventually exclude
// associated types.
self.substs.types.as_slice()
}
}
/// When type checking, we use the `ParameterEnvironment` to track
/// details about the type/lifetime parameters that are in scope.
/// It primarily stores the bounds information.
///
/// Note: This information might seem to be redundant with the data in
/// `tcx.ty_param_defs`, but it is not. That table contains the
/// parameter definitions from an "outside" perspective, but this
/// struct will contain the bounds for a parameter as seen from inside
/// the function body. Currently the only real distinction is that
/// bound lifetime parameters are replaced with free ones, but in the
/// future I hope to refine the representation of types so as to make
/// more distinctions clearer.
#[derive(Clone)]
pub struct ParameterEnvironment<'a, 'tcx:'a> {
pub tcx: &'a ctxt<'tcx>,
/// See `construct_free_substs` for details.
pub free_substs: Substs<'tcx>,
/// Each type parameter has an implicit region bound that
/// indicates it must outlive at least the function body (the user
/// may specify stronger requirements). This field indicates the
/// region of the callee.
pub implicit_region_bound: ty::Region,
/// 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: Vec<ty::Predicate<'tcx>>,
/// Caches the results of trait selection. This cache is used
/// for things that have to do with the parameters in scope.
pub selection_cache: traits::SelectionCache<'tcx>,
/// Caches the results of trait evaluation.
pub evaluation_cache: traits::EvaluationCache<'tcx>,
/// Scope that is attached to free regions for this scope. This
/// is usually the id of the fn body, but for more abstract scopes
/// like structs we often use the node-id of the struct.
///
/// FIXME(#3696). It would be nice to refactor so that free
/// regions don't have this implicit scope and instead introduce
/// relationships in the environment.
pub free_id_outlive: CodeExtent,
}
impl<'a, 'tcx> ParameterEnvironment<'a, 'tcx> {
pub fn with_caller_bounds(&self,
caller_bounds: Vec<ty::Predicate<'tcx>>)
-> ParameterEnvironment<'a,'tcx>
{
ParameterEnvironment {
tcx: self.tcx,
free_substs: self.free_substs.clone(),
implicit_region_bound: self.implicit_region_bound,
caller_bounds: caller_bounds,
selection_cache: traits::SelectionCache::new(),
evaluation_cache: traits::EvaluationCache::new(),
free_id_outlive: self.free_id_outlive,
}
}
pub fn for_item(cx: &'a ctxt<'tcx>, id: NodeId) -> ParameterEnvironment<'a, 'tcx> {
match cx.map.find(id) {
Some(ast_map::NodeImplItem(ref impl_item)) => {
match impl_item.node {
hir::ImplItemKind::Type(_) => {
// associated types don't have their own entry (for some reason),
// so for now just grab environment for the impl
let impl_id = cx.map.get_parent(id);
let impl_def_id = cx.map.local_def_id(impl_id);
let scheme = cx.lookup_item_type(impl_def_id);
let predicates = cx.lookup_predicates(impl_def_id);
cx.construct_parameter_environment(impl_item.span,
&scheme.generics,
&predicates,
cx.region_maps.item_extent(id))
}
hir::ImplItemKind::Const(_, _) => {
let def_id = cx.map.local_def_id(id);
let scheme = cx.lookup_item_type(def_id);
let predicates = cx.lookup_predicates(def_id);
cx.construct_parameter_environment(impl_item.span,
&scheme.generics,
&predicates,
cx.region_maps.item_extent(id))
}
hir::ImplItemKind::Method(_, ref body) => {
let method_def_id = cx.map.local_def_id(id);
match cx.impl_or_trait_item(method_def_id) {
MethodTraitItem(ref method_ty) => {
let method_generics = &method_ty.generics;
let method_bounds = &method_ty.predicates;
cx.construct_parameter_environment(
impl_item.span,
method_generics,
method_bounds,
cx.region_maps.call_site_extent(id, body.id))
}
_ => {
cx.sess
.bug("ParameterEnvironment::for_item(): \
got non-method item from impl method?!")
}
}
}
}
}
Some(ast_map::NodeTraitItem(trait_item)) => {
match trait_item.node {
hir::TypeTraitItem(..) => {
// associated types don't have their own entry (for some reason),
// so for now just grab environment for the trait
let trait_id = cx.map.get_parent(id);
let trait_def_id = cx.map.local_def_id(trait_id);
let trait_def = cx.lookup_trait_def(trait_def_id);
let predicates = cx.lookup_predicates(trait_def_id);
cx.construct_parameter_environment(trait_item.span,
&trait_def.generics,
&predicates,
cx.region_maps.item_extent(id))
}
hir::ConstTraitItem(..) => {
let def_id = cx.map.local_def_id(id);
let scheme = cx.lookup_item_type(def_id);
let predicates = cx.lookup_predicates(def_id);
cx.construct_parameter_environment(trait_item.span,
&scheme.generics,
&predicates,
cx.region_maps.item_extent(id))
}
hir::MethodTraitItem(_, ref body) => {
// Use call-site for extent (unless this is a
// trait method with no default; then fallback
// to the method id).
let method_def_id = cx.map.local_def_id(id);
match cx.impl_or_trait_item(method_def_id) {
MethodTraitItem(ref method_ty) => {
let method_generics = &method_ty.generics;
let method_bounds = &method_ty.predicates;
let extent = if let Some(ref body) = *body {
// default impl: use call_site extent as free_id_outlive bound.
cx.region_maps.call_site_extent(id, body.id)
} else {
// no default impl: use item extent as free_id_outlive bound.
cx.region_maps.item_extent(id)
};
cx.construct_parameter_environment(
trait_item.span,
method_generics,
method_bounds,
extent)
}
_ => {
cx.sess
.bug("ParameterEnvironment::for_item(): \
got non-method item from provided \
method?!")
}
}
}
}
}
Some(ast_map::NodeItem(item)) => {
match item.node {
hir::ItemFn(_, _, _, _, _, ref body) => {
// We assume this is a function.
let fn_def_id = cx.map.local_def_id(id);
let fn_scheme = cx.lookup_item_type(fn_def_id);
let fn_predicates = cx.lookup_predicates(fn_def_id);
cx.construct_parameter_environment(item.span,
&fn_scheme.generics,
&fn_predicates,
cx.region_maps.call_site_extent(id,
body.id))
}
hir::ItemEnum(..) |
hir::ItemStruct(..) |
hir::ItemImpl(..) |
hir::ItemConst(..) |
hir::ItemStatic(..) => {
let def_id = cx.map.local_def_id(id);
let scheme = cx.lookup_item_type(def_id);
let predicates = cx.lookup_predicates(def_id);
cx.construct_parameter_environment(item.span,
&scheme.generics,
&predicates,
cx.region_maps.item_extent(id))
}
hir::ItemTrait(..) => {
let def_id = cx.map.local_def_id(id);
let trait_def = cx.lookup_trait_def(def_id);
let predicates = cx.lookup_predicates(def_id);
cx.construct_parameter_environment(item.span,
&trait_def.generics,
&predicates,
cx.region_maps.item_extent(id))
}
_ => {
cx.sess.span_bug(item.span,
"ParameterEnvironment::from_item():
can't create a parameter \
environment for this kind of item")
}
}
}
Some(ast_map::NodeExpr(..)) => {
// This is a convenience to allow closures to work.
ParameterEnvironment::for_item(cx, cx.map.get_parent(id))
}
_ => {
cx.sess.bug(&format!("ParameterEnvironment::from_item(): \
`{}` is not an item",
cx.map.node_to_string(id)))
}
}
}
}
/// A "type scheme", in ML terminology, is a type combined with some
/// set of generic types that the type is, well, generic over. In Rust
/// terms, it is the "type" of a fn item or struct -- this type will
/// include various generic parameters that must be substituted when
/// the item/struct is referenced. That is called converting the type
/// scheme to a monotype.
///
/// - `generics`: the set of type parameters and their bounds
/// - `ty`: the base types, which may reference the parameters defined
/// in `generics`
///
/// Note that TypeSchemes are also sometimes called "polytypes" (and
/// in fact this struct used to carry that name, so you may find some
/// stray references in a comment or something). We try to reserve the
/// "poly" prefix to refer to higher-ranked things, as in
/// `PolyTraitRef`.
///
/// Note that each item also comes with predicates, see
/// `lookup_predicates`.
#[derive(Clone, Debug)]
pub struct TypeScheme<'tcx> {
pub generics: Generics<'tcx>,
pub ty: Ty<'tcx>,
}
bitflags! {
flags AdtFlags: u32 {
const NO_ADT_FLAGS = 0,
const IS_ENUM = 1 << 0,
const IS_DTORCK = 1 << 1, // is this a dtorck type?
const IS_DTORCK_VALID = 1 << 2,
const IS_PHANTOM_DATA = 1 << 3,
const IS_SIMD = 1 << 4,
const IS_FUNDAMENTAL = 1 << 5,
const IS_NO_DROP_FLAG = 1 << 6,
}
}
pub type AdtDef<'tcx> = &'tcx AdtDefData<'tcx, 'static>;
pub type VariantDef<'tcx> = &'tcx VariantDefData<'tcx, 'static>;
pub type FieldDef<'tcx> = &'tcx FieldDefData<'tcx, 'static>;
// See comment on AdtDefData for explanation
pub type AdtDefMaster<'tcx> = &'tcx AdtDefData<'tcx, 'tcx>;
pub type VariantDefMaster<'tcx> = &'tcx VariantDefData<'tcx, 'tcx>;
pub type FieldDefMaster<'tcx> = &'tcx FieldDefData<'tcx, 'tcx>;
pub struct VariantDefData<'tcx, 'container: 'tcx> {
/// 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 disr_val: Disr,
pub fields: Vec<FieldDefData<'tcx, 'container>>,
pub kind: VariantKind,
}
pub struct FieldDefData<'tcx, 'container: 'tcx> {
/// The field's DefId. NOTE: the fields of tuple-like enum variants
/// are not real items, and don't have entries in tcache etc.
pub did: DefId,
/// special_idents::unnamed_field.name
/// if this is a tuple-like field
pub name: Name,
pub vis: hir::Visibility,
/// TyIVar is used here to allow for variance (see the doc at
/// AdtDefData).
///
/// Note: direct accesses to `ty` must also add dep edges.
ty: ivar::TyIVar<'tcx, 'container>
}
/// The definition of an abstract data type - a struct or enum.
///
/// These are all interned (by intern_adt_def) into the adt_defs
/// table.
///
/// Because of the possibility of nested tcx-s, this type
/// needs 2 lifetimes: the traditional variant lifetime ('tcx)
/// bounding the lifetime of the inner types is of course necessary.
/// However, it is not sufficient - types from a child tcx must
/// not be leaked into the master tcx by being stored in an AdtDefData.
///
/// The 'container lifetime ensures that by outliving the container
/// tcx and preventing shorter-lived types from being inserted. When
/// write access is not needed, the 'container lifetime can be
/// erased to 'static, which can be done by the AdtDef wrapper.
pub struct AdtDefData<'tcx, 'container: 'tcx> {
pub did: DefId,
pub variants: Vec<VariantDefData<'tcx, 'container>>,
destructor: Cell<Option<DefId>>,
flags: Cell<AdtFlags>,
}
impl<'tcx, 'container> PartialEq for AdtDefData<'tcx, 'container> {
// AdtDefData are always interned and this is part of TyS equality
#[inline]
fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
}
impl<'tcx, 'container> Eq for AdtDefData<'tcx, 'container> {}
impl<'tcx, 'container> Hash for AdtDefData<'tcx, 'container> {
#[inline]
fn hash<H: Hasher>(&self, s: &mut H) {
(self as *const AdtDefData).hash(s)
}
}
impl<'tcx> Encodable for AdtDef<'tcx> {
fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
self.did.encode(s)
}
}
impl<'tcx> Decodable for AdtDef<'tcx> {
fn decode<D: Decoder>(d: &mut D) -> Result<AdtDef<'tcx>, D::Error> {
let def_id: DefId = try!{ Decodable::decode(d) };
cstore::tls::with_decoding_context(d, |dcx, _| {
let def_id = dcx.translate_def_id(def_id);
Ok(dcx.tcx().lookup_adt_def(def_id))
})
}
}
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub enum AdtKind { Struct, Enum }
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub enum VariantKind { Struct, Tuple, Unit }
impl<'tcx, 'container> AdtDefData<'tcx, 'container> {
fn new(tcx: &ctxt<'tcx>,
did: DefId,
kind: AdtKind,
variants: Vec<VariantDefData<'tcx, 'container>>) -> 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 attr::contains_name(&attrs, "unsafe_no_drop_flag") {
flags = flags | AdtFlags::IS_NO_DROP_FLAG;
}
if tcx.lookup_simd(did) {
flags = flags | AdtFlags::IS_SIMD;
}
if Some(did) == tcx.lang_items.phantom_data() {
flags = flags | AdtFlags::IS_PHANTOM_DATA;
}
if let AdtKind::Enum = kind {
flags = flags | AdtFlags::IS_ENUM;
}
AdtDefData {
did: did,
variants: variants,
flags: Cell::new(flags),
destructor: Cell::new(None)
}
}
fn calculate_dtorck(&'tcx self, tcx: &ctxt<'tcx>) {
if tcx.is_adt_dtorck(self) {
self.flags.set(self.flags.get() | AdtFlags::IS_DTORCK);
}
self.flags.set(self.flags.get() | AdtFlags::IS_DTORCK_VALID)
}
/// Returns the kind of the ADT - Struct or Enum.
#[inline]
pub fn adt_kind(&self) -> AdtKind {
if self.flags.get().intersects(AdtFlags::IS_ENUM) {
AdtKind::Enum
} else {
AdtKind::Struct
}
}
/// Returns whether this is a dtorck type. If this returns
/// true, this type being safe for destruction requires it to be
/// alive; Otherwise, only the contents are required to be.
#[inline]
pub fn is_dtorck(&'tcx self, tcx: &ctxt<'tcx>) -> bool {
if !self.flags.get().intersects(AdtFlags::IS_DTORCK_VALID) {
self.calculate_dtorck(tcx)
}
self.flags.get().intersects(AdtFlags::IS_DTORCK)
}
/// Returns whether this type is #[fundamental] for the purposes
/// of coherence checking.
#[inline]
pub fn is_fundamental(&self) -> bool {
self.flags.get().intersects(AdtFlags::IS_FUNDAMENTAL)
}
#[inline]
pub fn is_simd(&self) -> bool {
self.flags.get().intersects(AdtFlags::IS_SIMD)
}
/// Returns true if this is PhantomData<T>.
#[inline]
pub fn is_phantom_data(&self) -> bool {
self.flags.get().intersects(AdtFlags::IS_PHANTOM_DATA)
}
/// Returns whether this type has a destructor.
pub fn has_dtor(&self) -> bool {
match self.dtor_kind() {
NoDtor => false,
TraitDtor(..) => true
}
}
/// Asserts this is a struct and returns the struct's unique
/// variant.
pub fn struct_variant(&self) -> &VariantDefData<'tcx, 'container> {
assert!(self.adt_kind() == AdtKind::Struct);
&self.variants[0]
}
#[inline]
pub fn type_scheme(&self, tcx: &ctxt<'tcx>) -> TypeScheme<'tcx> {
tcx.lookup_item_type(self.did)
}
#[inline]
pub fn predicates(&self, tcx: &ctxt<'tcx>) -> GenericPredicates<'tcx> {
tcx.lookup_predicates(self.did)
}
/// Returns an iterator over all fields contained
/// by this ADT.
#[inline]
pub fn all_fields(&self) ->
iter::FlatMap<
slice::Iter<VariantDefData<'tcx, 'container>>,
slice::Iter<FieldDefData<'tcx, 'container>>,
for<'s> fn(&'s VariantDefData<'tcx, 'container>)
-> slice::Iter<'s, FieldDefData<'tcx, 'container>>
> {
self.variants.iter().flat_map(VariantDefData::fields_iter)
}
#[inline]
pub fn is_empty(&self) -> bool {
self.variants.is_empty()
}
#[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) -> &VariantDefData<'tcx, 'container> {
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::Def) -> &VariantDefData<'tcx, 'container> {
match def {
def::DefVariant(_, vid, _) => self.variant_with_id(vid),
def::DefStruct(..) | def::DefTy(..) => self.struct_variant(),
_ => panic!("unexpected def {:?} in variant_of_def", def)
}
}
pub fn destructor(&self) -> Option<DefId> {
self.destructor.get()
}
pub fn set_destructor(&self, dtor: DefId) {
self.destructor.set(Some(dtor));
}
pub fn dtor_kind(&self) -> DtorKind {
match self.destructor.get() {
Some(_) => {
TraitDtor(!self.flags.get().intersects(AdtFlags::IS_NO_DROP_FLAG))
}
None => NoDtor,
}
}
}
impl<'tcx, 'container> VariantDefData<'tcx, 'container> {
#[inline]
fn fields_iter(&self) -> slice::Iter<FieldDefData<'tcx, 'container>> {
self.fields.iter()
}
pub fn kind(&self) -> VariantKind {
self.kind
}
pub fn is_tuple_struct(&self) -> bool {
self.kind() == VariantKind::Tuple
}
#[inline]
pub fn find_field_named(&self,
name: ast::Name)
-> Option<&FieldDefData<'tcx, 'container>> {
self.fields.iter().find(|f| f.name == name)
}
#[inline]
pub fn index_of_field_named(&self,
name: ast::Name)
-> Option<usize> {
self.fields.iter().position(|f| f.name == name)
}
#[inline]
pub fn field_named(&self, name: ast::Name) -> &FieldDefData<'tcx, 'container> {
self.find_field_named(name).unwrap()
}
}
impl<'tcx, 'container> FieldDefData<'tcx, 'container> {
pub fn new(did: DefId,
name: Name,
vis: hir::Visibility) -> Self {
FieldDefData {
did: did,
name: name,
vis: vis,
ty: ivar::TyIVar::new()
}
}
pub fn ty(&self, tcx: &ctxt<'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
self.unsubst_ty().subst(tcx, subst)
}
pub fn unsubst_ty(&self) -> Ty<'tcx> {
self.ty.unwrap(DepNode::FieldTy(self.did))
}
pub fn fulfill_ty(&self, ty: Ty<'container>) {
self.ty.fulfill(DepNode::FieldTy(self.did), ty);
}
}
/// Records the substitutions used to translate the polytype for an
/// item into the monotype of an item reference.
#[derive(Clone)]
pub struct ItemSubsts<'tcx> {
pub substs: Substs<'tcx>,
}
#[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, 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.
FnClosureKind,
FnMutClosureKind,
FnOnceClosureKind,
}
impl ClosureKind {
pub fn trait_did(&self, cx: &ctxt) -> DefId {
let result = match *self {
FnClosureKind => cx.lang_items.require(FnTraitLangItem),
FnMutClosureKind => {
cx.lang_items.require(FnMutTraitLangItem)
}
FnOnceClosureKind => {
cx.lang_items.require(FnOnceTraitLangItem)
}
};
match result {
Ok(trait_did) => trait_did,
Err(err) => cx.sess.fatal(&err[..]),
}
}
/// 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) {
(FnClosureKind, FnClosureKind) => true,
(FnClosureKind, FnMutClosureKind) => true,
(FnClosureKind, FnOnceClosureKind) => true,
(FnMutClosureKind, FnMutClosureKind) => true,
(FnMutClosureKind, FnOnceClosureKind) => true,
(FnOnceClosureKind, FnOnceClosureKind) => 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) -> IntoIter<Ty<'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<'tcx> ItemSubsts<'tcx> {
pub fn empty() -> ItemSubsts<'tcx> {
ItemSubsts { substs: Substs::empty() }
}
pub fn is_noop(&self) -> bool {
self.substs.is_noop()
}
}
#[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,
}
}
}
/// Helper for looking things up in the various maps that are populated during
/// typeck::collect (e.g., `cx.impl_or_trait_items`, `cx.tcache`, etc). All of
/// these share the pattern that if the id is local, it should have been loaded
/// into the map by the `typeck::collect` phase. If the def-id is external,
/// then we have to go consult the crate loading code (and cache the result for
/// the future).
fn lookup_locally_or_in_crate_store<M, F>(descr: &str,
def_id: DefId,
map: &M,
load_external: F)
-> M::Value where
M: MemoizationMap<Key=DefId>,
F: FnOnce() -> M::Value,
{
map.memoize(def_id, || {
if def_id.is_local() {
panic!("No def'n found for {:?} in tcx.{}", def_id, descr);
}
load_external()
})
}
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",
}
}
}
impl<'tcx> ctxt<'tcx> {
pub fn node_id_to_type(&self, id: NodeId) -> Ty<'tcx> {
match self.node_id_to_type_opt(id) {
Some(ty) => ty,
None => self.sess.bug(
&format!("node_id_to_type: no type for node `{}`",
self.map.node_to_string(id)))
}
}
pub fn node_id_to_type_opt(&self, id: NodeId) -> Option<Ty<'tcx>> {
self.tables.borrow().node_types.get(&id).cloned()
}
pub fn node_id_item_substs(&self, id: NodeId) -> ItemSubsts<'tcx> {
match self.tables.borrow().item_substs.get(&id) {
None => ItemSubsts::empty(),
Some(ts) => ts.clone(),
}
}
// Returns the type of a pattern as a monotype. Like @expr_ty, this function
// doesn't provide type parameter substitutions.
pub fn pat_ty(&self, pat: &hir::Pat) -> Ty<'tcx> {
self.node_id_to_type(pat.id)
}
pub fn pat_ty_opt(&self, pat: &hir::Pat) -> Option<Ty<'tcx>> {
self.node_id_to_type_opt(pat.id)
}
// Returns the type of an expression as a monotype.
//
// NB (1): This is the PRE-ADJUSTMENT TYPE for the expression. That is, in
// some cases, we insert `AutoAdjustment` annotations such as auto-deref or
// auto-ref. The type returned by this function does not consider such
// adjustments. See `expr_ty_adjusted()` instead.
//
// NB (2): This type doesn't provide type parameter substitutions; e.g. if you
// ask for the type of "id" in "id(3)", it will return "fn(&isize) -> isize"
// instead of "fn(ty) -> T with T = isize".
pub fn expr_ty(&self, expr: &hir::Expr) -> Ty<'tcx> {
self.node_id_to_type(expr.id)
}
pub fn expr_ty_opt(&self, expr: &hir::Expr) -> Option<Ty<'tcx>> {
self.node_id_to_type_opt(expr.id)
}
/// Returns the type of `expr`, considering any `AutoAdjustment`
/// entry recorded for that expression.
///
/// It would almost certainly be better to store the adjusted ty in with
/// the `AutoAdjustment`, but I opted not to do this because it would
/// require serializing and deserializing the type and, although that's not
/// hard to do, I just hate that code so much I didn't want to touch it
/// unless it was to fix it properly, which seemed a distraction from the
/// thread at hand! -nmatsakis
pub fn expr_ty_adjusted(&self, expr: &hir::Expr) -> Ty<'tcx> {
self.expr_ty(expr)
.adjust(self, expr.span, expr.id,
self.tables.borrow().adjustments.get(&expr.id),
|method_call| {
self.tables.borrow().method_map.get(&method_call).map(|method| method.ty)
})
}
pub fn expr_span(&self, id: NodeId) -> Span {
match self.map.find(id) {
Some(ast_map::NodeExpr(e)) => {
e.span
}
Some(f) => {
self.sess.bug(&format!("Node id {} is not an expr: {:?}",
id, f));
}
None => {
self.sess.bug(&format!("Node id {} is not present \
in the node map", id));
}
}
}
pub fn local_var_name_str(&self, id: NodeId) -> InternedString {
match self.map.find(id) {
Some(ast_map::NodeLocal(pat)) => {
match pat.node {
hir::PatIdent(_, ref path1, _) => path1.node.name.as_str(),
_ => {
self.sess.bug(&format!("Variable id {} maps to {:?}, not local", id, pat));
},
}
},
r => self.sess.bug(&format!("Variable id {} maps to {:?}, not local", id, r)),
}
}
pub fn resolve_expr(&self, expr: &hir::Expr) -> def::Def {
match self.def_map.borrow().get(&expr.id) {
Some(def) => def.full_def(),
None => {
self.sess.span_bug(expr.span, &format!(
"no def-map entry for expr {}", expr.id));
}
}
}
pub fn expr_is_lval(&self, expr: &hir::Expr) -> bool {
match expr.node {
hir::ExprPath(..) => {
// We can't use resolve_expr here, as this needs to run on broken
// programs. We don't need to through - associated items are all
// rvalues.
match self.def_map.borrow().get(&expr.id) {
Some(&def::PathResolution {
base_def: def::DefStatic(..), ..
}) | Some(&def::PathResolution {
base_def: def::DefUpvar(..), ..
}) | Some(&def::PathResolution {
base_def: def::DefLocal(..), ..
}) => {
true
}
Some(&def::PathResolution { base_def: def::DefErr, .. })=> true,
Some(..) => false,
None => self.sess.span_bug(expr.span, &format!(
"no def for path {}", expr.id))
}
}
hir::ExprType(ref e, _) => {
self.expr_is_lval(e)
}
hir::ExprUnary(hir::UnDeref, _) |
hir::ExprField(..) |
hir::ExprTupField(..) |
hir::ExprIndex(..) => {
true
}
hir::ExprCall(..) |
hir::ExprMethodCall(..) |
hir::ExprStruct(..) |
hir::ExprRange(..) |
hir::ExprTup(..) |
hir::ExprIf(..) |
hir::ExprMatch(..) |
hir::ExprClosure(..) |
hir::ExprBlock(..) |
hir::ExprRepeat(..) |
hir::ExprVec(..) |
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::ExprCast(..) => {
false
}
}
}
pub fn provided_trait_methods(&self, id: DefId) -> Vec<Rc<Method<'tcx>>> {
if let Some(id) = self.map.as_local_node_id(id) {
if let ItemTrait(_, _, _, ref ms) = self.map.expect_item(id).node {
ms.iter().filter_map(|ti| {
if let hir::MethodTraitItem(_, Some(_)) = ti.node {
match self.impl_or_trait_item(self.map.local_def_id(ti.id)) {
MethodTraitItem(m) => Some(m),
_ => {
self.sess.bug("provided_trait_methods(): \
non-method item found from \
looking up provided method?!")
}
}
} else {
None
}
}).collect()
} else {
self.sess.bug(&format!("provided_trait_methods: `{:?}` is not a trait", id))
}
} else {
self.sess.cstore.provided_trait_methods(self, id)
}
}
pub fn associated_consts(&self, id: DefId) -> Vec<Rc<AssociatedConst<'tcx>>> {
if let Some(id) = self.map.as_local_node_id(id) {
match self.map.expect_item(id).node {
ItemTrait(_, _, _, ref tis) => {
tis.iter().filter_map(|ti| {
if let hir::ConstTraitItem(_, _) = ti.node {
match self.impl_or_trait_item(self.map.local_def_id(ti.id)) {
ConstTraitItem(ac) => Some(ac),
_ => {
self.sess.bug("associated_consts(): \
non-const item found from \
looking up a constant?!")
}
}
} else {
None
}
}).collect()
}
ItemImpl(_, _, _, _, _, ref iis) => {
iis.iter().filter_map(|ii| {
if let hir::ImplItemKind::Const(_, _) = ii.node {
match self.impl_or_trait_item(self.map.local_def_id(ii.id)) {
ConstTraitItem(ac) => Some(ac),
_ => {
self.sess.bug("associated_consts(): \
non-const item found from \
looking up a constant?!")
}
}
} else {
None
}
}).collect()
}
_ => {
self.sess.bug(&format!("associated_consts: `{:?}` is not a trait \
or impl", id))
}
}
} else {
self.sess.cstore.associated_consts(self, id)
}
}
pub fn trait_impl_polarity(&self, id: DefId) -> Option<hir::ImplPolarity> {
if let Some(id) = self.map.as_local_node_id(id) {
match self.map.find(id) {
Some(ast_map::NodeItem(item)) => {
match item.node {
hir::ItemImpl(_, polarity, _, _, _, _) => Some(polarity),
_ => None
}
}
_ => None
}
} else {
self.sess.cstore.impl_polarity(id)
}
}
pub fn custom_coerce_unsized_kind(&self, did: DefId) -> adjustment::CustomCoerceUnsized {
self.custom_coerce_unsized_kinds.memoize(did, || {
let (kind, src) = if did.krate != LOCAL_CRATE {
(self.sess.cstore.custom_coerce_unsized_kind(did), "external")
} else {
(None, "local")
};
match kind {
Some(kind) => kind,
None => {
self.sess.bug(&format!("custom_coerce_unsized_kind: \
{} impl `{}` is missing its kind",
src, self.item_path_str(did)));
}
}
})
}
pub fn impl_or_trait_item(&self, id: DefId) -> ImplOrTraitItem<'tcx> {
lookup_locally_or_in_crate_store(
"impl_or_trait_items", id, &self.impl_or_trait_items,
|| self.sess.cstore.impl_or_trait_item(self, id))
}
pub fn trait_item_def_ids(&self, id: DefId) -> Rc<Vec<ImplOrTraitItemId>> {
lookup_locally_or_in_crate_store(
"trait_item_def_ids", id, &self.trait_item_def_ids,
|| Rc::new(self.sess.cstore.trait_item_def_ids(id)))
}
/// Returns the trait-ref corresponding to a given impl, or None if it is
/// an inherent impl.
pub fn impl_trait_ref(&self, id: DefId) -> Option<TraitRef<'tcx>> {
lookup_locally_or_in_crate_store(
"impl_trait_refs", id, &self.impl_trait_refs,
|| self.sess.cstore.impl_trait_ref(self, id))
}
/// Returns whether this DefId refers to an impl
pub fn is_impl(&self, id: DefId) -> bool {
if let Some(id) = self.map.as_local_node_id(id) {
if let Some(ast_map::NodeItem(
&hir::Item { node: hir::ItemImpl(..), .. })) = self.map.find(id) {
true
} else {
false
}
} else {
self.sess.cstore.is_impl(id)
}
}
pub fn trait_ref_to_def_id(&self, tr: &hir::TraitRef) -> DefId {
self.def_map.borrow().get(&tr.ref_id).expect("no def-map entry for trait").def_id()
}
pub fn item_path_str(&self, id: DefId) -> String {
self.with_path(id, |path| ast_map::path_to_string(path))
}
pub fn def_path(&self, id: DefId) -> ast_map::DefPath {
if id.is_local() {
self.map.def_path(id)
} else {
self.sess.cstore.def_path(id)
}
}
pub fn with_path<T, F>(&self, id: DefId, f: F) -> T where
F: FnOnce(ast_map::PathElems) -> T,
{
if let Some(id) = self.map.as_local_node_id(id) {
self.map.with_path(id, f)
} else {
f(self.sess.cstore.item_path(id).iter().cloned().chain(LinkedPath::empty()))
}
}
pub fn item_name(&self, id: DefId) -> ast::Name {
if let Some(id) = self.map.as_local_node_id(id) {
self.map.get_path_elem(id).name()
} else {
self.sess.cstore.item_name(id)
}
}
// Register a given item type
pub fn register_item_type(&self, did: DefId, ty: TypeScheme<'tcx>) {
self.tcache.borrow_mut().insert(did, ty);
}
// If the given item is in an external crate, looks up its type and adds it to
// the type cache. Returns the type parameters and type.
pub fn lookup_item_type(&self, did: DefId) -> TypeScheme<'tcx> {
lookup_locally_or_in_crate_store(
"tcache", did, &self.tcache,
|| self.sess.cstore.item_type(self, did))
}
/// Given the did of a trait, returns its canonical trait ref.
pub fn lookup_trait_def(&self, did: DefId) -> &'tcx TraitDef<'tcx> {
lookup_locally_or_in_crate_store(
"trait_defs", did, &self.trait_defs,
|| self.alloc_trait_def(self.sess.cstore.trait_def(self, did))
)
}
/// Given the did of an ADT, return a master reference to its
/// definition. Unless you are planning on fulfilling the ADT's fields,
/// use lookup_adt_def instead.
pub fn lookup_adt_def_master(&self, did: DefId) -> AdtDefMaster<'tcx> {
lookup_locally_or_in_crate_store(
"adt_defs", did, &self.adt_defs,
|| self.sess.cstore.adt_def(self, did)
)
}
/// Given the did of an ADT, return a reference to its definition.
pub fn lookup_adt_def(&self, did: DefId) -> AdtDef<'tcx> {
// when reverse-variance goes away, a transmute::<AdtDefMaster,AdtDef>
// woud be needed here.
self.lookup_adt_def_master(did)
}
/// Given the did of an item, returns its full set of predicates.
pub fn lookup_predicates(&self, did: DefId) -> GenericPredicates<'tcx> {
lookup_locally_or_in_crate_store(
"predicates", did, &self.predicates,
|| self.sess.cstore.item_predicates(self, did))
}
/// Given the did of a trait, returns its superpredicates.
pub fn lookup_super_predicates(&self, did: DefId) -> GenericPredicates<'tcx> {
lookup_locally_or_in_crate_store(
"super_predicates", did, &self.super_predicates,
|| self.sess.cstore.item_super_predicates(self, did))
}
/// If `type_needs_drop` returns true, then `ty` is definitely
/// non-copy and *might* have a destructor attached; if it returns
/// false, then `ty` definitely has no destructor (i.e. no drop glue).
///
/// (Note that this implies that if `ty` has a destructor attached,
/// then `type_needs_drop` will definitely return `true` for `ty`.)
pub fn type_needs_drop_given_env<'a>(&self,
ty: Ty<'tcx>,
param_env: &ty::ParameterEnvironment<'a,'tcx>) -> bool {
// Issue #22536: We first query type_moves_by_default. It sees a
// normalized version of the type, and therefore will definitely
// know whether the type implements Copy (and thus needs no
// cleanup/drop/zeroing) ...
let implements_copy = !ty.moves_by_default(param_env, DUMMY_SP);
if implements_copy { return false; }
// ... (issue #22536 continued) but as an optimization, still use
// prior logic of asking if the `needs_drop` bit is set; we need
// not zero non-Copy types if they have no destructor.
// FIXME(#22815): Note that calling `ty::type_contents` is a
// conservative heuristic; it may report that `needs_drop` is set
// when actual type does not actually have a destructor associated
// with it. But since `ty` absolutely did not have the `Copy`
// bound attached (see above), it is sound to treat it as having a
// destructor (e.g. zero its memory on move).
let contents = ty.type_contents(self);
debug!("type_needs_drop ty={:?} contents={:?}", ty, contents);
contents.needs_drop(self)
}
/// Get the attributes of a definition.
pub fn get_attrs(&self, did: DefId) -> Cow<'tcx, [ast::Attribute]> {
if let Some(id) = self.map.as_local_node_id(did) {
Cow::Borrowed(self.map.attrs(id))
} else {
Cow::Owned(self.sess.cstore.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))
}
/// Determine whether an item is annotated with `#[repr(packed)]`
pub fn lookup_packed(&self, did: DefId) -> bool {
self.lookup_repr_hints(did).contains(&attr::ReprPacked)
}
/// Determine whether an item is annotated with `#[simd]`
pub fn lookup_simd(&self, did: DefId) -> bool {
self.has_attr(did, "simd")
|| self.lookup_repr_hints(did).contains(&attr::ReprSimd)
}
pub fn item_variances(&self, item_id: DefId) -> Rc<ItemVariances> {
lookup_locally_or_in_crate_store(
"item_variance_map", item_id, &self.item_variance_map,
|| Rc::new(self.sess.cstore.item_variances(item_id)))
}
pub fn trait_has_default_impl(&self, trait_def_id: DefId) -> bool {
self.populate_implementations_for_trait_if_necessary(trait_def_id);
let def = self.lookup_trait_def(trait_def_id);
def.flags.get().intersects(TraitFlags::HAS_DEFAULT_IMPL)
}
/// Records a trait-to-implementation mapping.
pub fn record_trait_has_default_impl(&self, trait_def_id: DefId) {
let def = self.lookup_trait_def(trait_def_id);
def.flags.set(def.flags.get() | TraitFlags::HAS_DEFAULT_IMPL)
}
/// Load primitive inherent implementations if necessary
pub fn populate_implementations_for_primitive_if_necessary(&self,
primitive_def_id: DefId) {
if primitive_def_id.is_local() {
return
}
// The primitive is not local, hence we are reading this out
// of metadata.
let _ignore = self.dep_graph.in_ignore();
if self.populated_external_primitive_impls.borrow().contains(&primitive_def_id) {
return
}
debug!("populate_implementations_for_primitive_if_necessary: searching for {:?}",
primitive_def_id);
let impl_items = self.sess.cstore.impl_items(primitive_def_id);
// Store the implementation info.
self.impl_items.borrow_mut().insert(primitive_def_id, impl_items);
self.populated_external_primitive_impls.borrow_mut().insert(primitive_def_id);
}
/// Populates the type context with all the inherent implementations for
/// the given type if necessary.
pub fn populate_inherent_implementations_for_type_if_necessary(&self,
type_id: DefId) {
if type_id.is_local() {
return
}
// The type is not local, hence we are reading this out of
// metadata and don't need to track edges.
let _ignore = self.dep_graph.in_ignore();
if self.populated_external_types.borrow().contains(&type_id) {
return
}
debug!("populate_inherent_implementations_for_type_if_necessary: searching for {:?}",
type_id);
let inherent_impls = self.sess.cstore.inherent_implementations_for_type(type_id);
for &impl_def_id in &inherent_impls {
// Store the implementation info.
let impl_items = self.sess.cstore.impl_items(impl_def_id);
self.impl_items.borrow_mut().insert(impl_def_id, impl_items);
}
self.inherent_impls.borrow_mut().insert(type_id, Rc::new(inherent_impls));
self.populated_external_types.borrow_mut().insert(type_id);
}
/// Populates the type context with all the implementations for the given
/// trait if necessary.
pub fn populate_implementations_for_trait_if_necessary(&self, trait_id: DefId) {
if trait_id.is_local() {
return
}
// The type is not local, hence we are reading this out of
// metadata and don't need to track edges.
let _ignore = self.dep_graph.in_ignore();
let def = self.lookup_trait_def(trait_id);
if def.flags.get().intersects(TraitFlags::IMPLS_VALID) {
return;
}
debug!("populate_implementations_for_trait_if_necessary: searching for {:?}", def);
if self.sess.cstore.is_defaulted_trait(trait_id) {
self.record_trait_has_default_impl(trait_id);
}
for impl_def_id in self.sess.cstore.implementations_of_trait(trait_id) {
let impl_items = self.sess.cstore.impl_items(impl_def_id);
let trait_ref = self.impl_trait_ref(impl_def_id).unwrap();
// Record the trait->implementation mapping.
def.record_impl(self, impl_def_id, trait_ref);
// For any methods that use a default implementation, add them to
// the map. This is a bit unfortunate.
for impl_item_def_id in &impl_items {
let method_def_id = impl_item_def_id.def_id();
// load impl items eagerly for convenience
// FIXME: we may want to load these lazily
self.impl_or_trait_item(method_def_id);
}
// Store the implementation info.
self.impl_items.borrow_mut().insert(impl_def_id, impl_items);
}
def.flags.set(def.flags.get() | TraitFlags::IMPLS_VALID);
}
pub fn closure_kind(&self, def_id: DefId) -> ty::ClosureKind {
Tables::closure_kind(&self.tables, self, def_id)
}
pub fn closure_type(&self,
def_id: DefId,
substs: &ClosureSubsts<'tcx>)
-> ty::ClosureTy<'tcx>
{
Tables::closure_type(&self.tables, self, def_id, substs)
}
/// 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> {
if def_id.krate != LOCAL_CRATE {
return match self.sess.cstore.impl_or_trait_item(self, def_id).container() {
TraitContainer(_) => None,
ImplContainer(def_id) => Some(def_id),
};
}
match self.impl_or_trait_items.borrow().get(&def_id).cloned() {
Some(trait_item) => {
match trait_item.container() {
TraitContainer(_) => None,
ImplContainer(def_id) => Some(def_id),
}
}
None => None
}
}
/// If the given def ID describes an item belonging to a trait (either a
/// default method or an implementation of a trait method), return the ID of
/// the trait that the method belongs to. Otherwise, return `None`.
pub fn trait_of_item(&self, def_id: DefId) -> Option<DefId> {
if def_id.krate != LOCAL_CRATE {
return self.sess.cstore.trait_of_item(self, def_id);
}
match self.impl_or_trait_items.borrow().get(&def_id).cloned() {
Some(impl_or_trait_item) => {
match impl_or_trait_item.container() {
TraitContainer(def_id) => Some(def_id),
ImplContainer(def_id) => self.trait_id_of_impl(def_id),
}
}
None => None
}
}
/// If the given def ID describes an item belonging to a trait, (either a
/// default method or an implementation of a trait method), return the ID of
/// the method inside trait definition (this means that if the given def ID
/// is already that of the original trait method, then the return value is
/// the same).
/// Otherwise, return `None`.
pub fn trait_item_of_item(&self, def_id: DefId) -> Option<ImplOrTraitItemId> {
let impl_item = match self.impl_or_trait_items.borrow().get(&def_id) {
Some(m) => m.clone(),
None => return None,
};
let name = impl_item.name();
match self.trait_of_item(def_id) {
Some(trait_did) => {
self.trait_items(trait_did).iter()
.find(|item| item.name() == name)
.map(|item| item.id())
}
None => None
}
}
/// Construct a parameter environment suitable for static contexts or other contexts where there
/// are no free type/lifetime parameters in scope.
pub fn empty_parameter_environment<'a>(&'a self)
-> ParameterEnvironment<'a,'tcx> {
// for an empty parameter environment, there ARE no free
// regions, so it shouldn't matter what we use for the free id
let free_id_outlive = self.region_maps.node_extent(ast::DUMMY_NODE_ID);
ty::ParameterEnvironment { tcx: self,
free_substs: Substs::empty(),
caller_bounds: Vec::new(),
implicit_region_bound: ty::ReEmpty,
selection_cache: traits::SelectionCache::new(),
evaluation_cache: traits::EvaluationCache::new(),
free_id_outlive: free_id_outlive }
}
/// Constructs and returns a substitution that can be applied to move from
/// the "outer" view of a type or method to the "inner" view.
/// In general, this means converting from bound parameters to
/// free parameters. Since we currently represent bound/free type
/// parameters in the same way, this only has an effect on regions.
pub fn construct_free_substs(&self, generics: &Generics<'tcx>,
free_id_outlive: CodeExtent) -> Substs<'tcx> {
// map T => T
let mut types = VecPerParamSpace::empty();
for def in generics.types.as_slice() {
debug!("construct_parameter_environment(): push_types_from_defs: def={:?}",
def);
types.push(def.space, self.mk_param_from_def(def));
}
// map bound 'a => free 'a
let mut regions = VecPerParamSpace::empty();
for def in generics.regions.as_slice() {
let region =
ReFree(FreeRegion { scope: free_id_outlive,
bound_region: BrNamed(def.def_id, def.name) });
debug!("push_region_params {:?}", region);
regions.push(def.space, region);
}
Substs {
types: types,
regions: subst::NonerasedRegions(regions)
}
}
/// See `ParameterEnvironment` struct def'n for details.
/// If you were using `free_id: NodeId`, you might try `self.region_maps.item_extent(free_id)`
/// for the `free_id_outlive` parameter. (But note that that is not always quite right.)
pub fn construct_parameter_environment<'a>(&'a self,
span: Span,
generics: &ty::Generics<'tcx>,
generic_predicates: &ty::GenericPredicates<'tcx>,
free_id_outlive: CodeExtent)
-> ParameterEnvironment<'a, 'tcx>
{
//
// Construct the free substs.
//
let free_substs = self.construct_free_substs(generics, free_id_outlive);
//
// Compute the bounds on Self and the type parameters.
//
let bounds = generic_predicates.instantiate(self, &free_substs);
let bounds = self.liberate_late_bound_regions(free_id_outlive, &ty::Binder(bounds));
let predicates = bounds.predicates.into_vec();
// 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::ParameterEnvironment {
tcx: self,
free_substs: free_substs,
implicit_region_bound: ty::ReScope(free_id_outlive),
caller_bounds: predicates,
selection_cache: traits::SelectionCache::new(),
evaluation_cache: traits::EvaluationCache::new(),
free_id_outlive: free_id_outlive,
};
let cause = traits::ObligationCause::misc(span, free_id_outlive.node_id(&self.region_maps));
traits::normalize_param_env_or_error(unnormalized_env, cause)
}
pub fn is_method_call(&self, expr_id: NodeId) -> bool {
self.tables.borrow().method_map.contains_key(&MethodCall::expr(expr_id))
}
pub fn is_overloaded_autoderef(&self, expr_id: NodeId, autoderefs: u32) -> bool {
self.tables.borrow().method_map.contains_key(&MethodCall::autoderef(expr_id,
autoderefs))
}
pub fn upvar_capture(&self, upvar_id: ty::UpvarId) -> Option<ty::UpvarCapture> {
Some(self.tables.borrow().upvar_capture_map.get(&upvar_id).unwrap().clone())
}
pub fn visit_all_items_in_krate<V,F>(&self,
dep_node_fn: F,
visitor: &mut V)
where F: FnMut(DefId) -> DepNode, V: Visitor<'tcx>
{
dep_graph::visit_all_items_in_krate(self, dep_node_fn, visitor);
}
}
/// The category of explicit self.
#[derive(Clone, Copy, Eq, PartialEq, Debug)]
pub enum ExplicitSelfCategory {
Static,
ByValue,
ByReference(Region, hir::Mutability),
ByBox,
}
/// A free variable referred to in a function.
#[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
pub struct Freevar {
/// The variable being accessed free.
pub def: def::Def,
// First span where it is accessed (there can be multiple).
pub span: Span
}
pub type FreevarMap = NodeMap<Vec<Freevar>>;
pub type CaptureModeMap = NodeMap<hir::CaptureClause>;
// Trait method resolution
pub type TraitMap = NodeMap<Vec<DefId>>;
// Map from the NodeId of a glob import to a list of items which are actually
// imported.
pub type GlobMap = HashMap<NodeId, HashSet<Name>>;
impl<'tcx> ctxt<'tcx> {
pub fn with_freevars<T, F>(&self, fid: NodeId, f: F) -> T where
F: FnOnce(&[Freevar]) -> T,
{
match self.freevars.borrow().get(&fid) {
None => f(&[]),
Some(d) => f(&d[..])
}
}
pub fn make_substs_for_receiver_types(&self,
trait_ref: &ty::TraitRef<'tcx>,
method: &ty::Method<'tcx>)
-> subst::Substs<'tcx>
{
/*!
* Substitutes the values for the receiver's type parameters
* that are found in method, leaving the method's type parameters
* intact.
*/
let meth_tps: Vec<Ty> =
method.generics.types.get_slice(subst::FnSpace)
.iter()
.map(|def| self.mk_param_from_def(def))
.collect();
let meth_regions: Vec<ty::Region> =
method.generics.regions.get_slice(subst::FnSpace)
.iter()
.map(|def| def.to_early_bound_region())
.collect();
trait_ref.substs.clone().with_method(meth_tps, meth_regions)
}
}