Skip to content
Permalink
Branch: master
Find file Copy path
Find file Copy path
Fetching contributors…
Cannot retrieve contributors at this time
3403 lines (3021 sloc) 121 KB
// ignore-tidy-filelength
pub use self::Variance::*;
pub use self::AssocItemContainer::*;
pub use self::BorrowKind::*;
pub use self::IntVarValue::*;
pub use self::fold::TypeFoldable;
use crate::hir::{map as hir_map, GlobMap, TraitMap};
use crate::hir::Node;
use crate::hir::def::{Res, DefKind, CtorOf, CtorKind, ExportMap};
use crate::hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
use rustc_data_structures::svh::Svh;
use rustc_macros::HashStable;
use crate::ich::Fingerprint;
use crate::ich::StableHashingContext;
use crate::infer::canonical::Canonical;
use crate::middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
use crate::middle::resolve_lifetime::ObjectLifetimeDefault;
use crate::mir::Body;
use crate::mir::interpret::{GlobalId, ErrorHandled};
use crate::mir::GeneratorLayout;
use crate::session::CrateDisambiguator;
use crate::traits::{self, Reveal};
use crate::ty;
use crate::ty::layout::VariantIdx;
use crate::ty::subst::{Subst, InternalSubsts, SubstsRef};
use crate::ty::util::{IntTypeExt, Discr};
use crate::ty::walk::TypeWalker;
use crate::util::captures::Captures;
use crate::util::nodemap::{NodeSet, DefIdMap, FxHashMap};
use arena::SyncDroplessArena;
use crate::session::DataTypeKind;
use serialize::{self, Encodable, Encoder};
use std::cell::RefCell;
use std::cmp::{self, Ordering};
use std::fmt;
use std::hash::{Hash, Hasher};
use std::ops::Deref;
use rustc_data_structures::sync::{self, Lrc, ParallelIterator, par_iter};
use std::slice;
use std::{mem, ptr};
use std::ops::Range;
use syntax::ast::{self, Name, Ident, NodeId};
use syntax::attr;
use syntax::ext::hygiene::ExpnId;
use syntax::symbol::{kw, sym, Symbol, LocalInternedString, InternedString};
use syntax_pos::Span;
use smallvec;
use rustc_data_structures::fx::FxIndexMap;
use rustc_data_structures::indexed_vec::{Idx, IndexVec};
use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
HashStable};
use crate::hir;
pub use self::sty::{Binder, BoundTy, BoundTyKind, BoundVar, DebruijnIndex, INNERMOST};
pub use self::sty::{FnSig, GenSig, CanonicalPolyFnSig, PolyFnSig, PolyGenSig};
pub use self::sty::{InferTy, ParamTy, ParamConst, InferConst, ProjectionTy, ExistentialPredicate};
pub use self::sty::{ClosureSubsts, GeneratorSubsts, UpvarSubsts, TypeAndMut};
pub use self::sty::{TraitRef, TyKind, PolyTraitRef};
pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
pub use self::sty::{ExistentialProjection, PolyExistentialProjection, Const};
pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
pub use self::sty::RegionKind;
pub use self::sty::{TyVid, IntVid, FloatVid, ConstVid, RegionVid};
pub use self::sty::BoundRegion::*;
pub use self::sty::InferTy::*;
pub use self::sty::RegionKind::*;
pub use self::sty::TyKind::*;
pub use self::binding::BindingMode;
pub use self::binding::BindingMode::*;
pub use self::context::{TyCtxt, FreeRegionInfo, AllArenas, tls, keep_local};
pub use self::context::{Lift, TypeckTables, CtxtInterners, GlobalCtxt};
pub use self::context::{
UserTypeAnnotationIndex, UserType, CanonicalUserType,
CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, ResolvedOpaqueTy,
};
pub use self::instance::{Instance, InstanceDef};
pub use self::trait_def::TraitDef;
pub use self::query::queries;
pub mod adjustment;
pub mod binding;
pub mod cast;
#[macro_use]
pub mod codec;
mod constness;
pub mod error;
mod erase_regions;
pub mod fast_reject;
pub mod flags;
pub mod fold;
pub mod inhabitedness;
pub mod layout;
pub mod _match;
pub mod outlives;
pub mod print;
pub mod query;
pub mod relate;
pub mod steal;
pub mod subst;
pub mod trait_def;
pub mod walk;
pub mod wf;
pub mod util;
mod context;
mod instance;
mod structural_impls;
mod sty;
// Data types
#[derive(Clone)]
pub struct Resolutions {
pub trait_map: TraitMap,
pub maybe_unused_trait_imports: NodeSet,
pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
pub export_map: ExportMap<NodeId>,
pub glob_map: GlobMap,
/// Extern prelude entries. The value is `true` if the entry was introduced
/// via `extern crate` item and not `--extern` option or compiler built-in.
pub extern_prelude: FxHashMap<Name, bool>,
}
#[derive(Clone, Copy, PartialEq, Eq, Debug, HashStable)]
pub enum AssocItemContainer {
TraitContainer(DefId),
ImplContainer(DefId),
}
impl AssocItemContainer {
/// Asserts that this is the `DefId` of an associated item declared
/// in a trait, and returns the trait `DefId`.
pub fn assert_trait(&self) -> DefId {
match *self {
TraitContainer(id) => id,
_ => bug!("associated item has wrong container type: {:?}", self)
}
}
pub fn id(&self) -> DefId {
match *self {
TraitContainer(id) => id,
ImplContainer(id) => id,
}
}
}
/// The "header" of an impl is everything outside the body: a Self type, a trait
/// ref (in the case of a trait impl), and a set of predicates (from the
/// bounds / where-clauses).
#[derive(Clone, PartialEq, Eq, Hash, Debug)]
pub struct ImplHeader<'tcx> {
pub impl_def_id: DefId,
pub self_ty: Ty<'tcx>,
pub trait_ref: Option<TraitRef<'tcx>>,
pub predicates: Vec<Predicate<'tcx>>,
}
#[derive(Copy, Clone, Debug, PartialEq, HashStable)]
pub struct AssocItem {
pub def_id: DefId,
#[stable_hasher(project(name))]
pub ident: Ident,
pub kind: AssocKind,
pub vis: Visibility,
pub defaultness: hir::Defaultness,
pub container: AssocItemContainer,
/// Whether this is a method with an explicit self
/// as its first argument, allowing method calls.
pub method_has_self_argument: bool,
}
#[derive(Copy, Clone, PartialEq, Eq, Debug, Hash, RustcEncodable, RustcDecodable, HashStable)]
pub enum AssocKind {
Const,
Method,
Existential,
Type
}
impl AssocItem {
pub fn def_kind(&self) -> DefKind {
match self.kind {
AssocKind::Const => DefKind::AssocConst,
AssocKind::Method => DefKind::Method,
AssocKind::Type => DefKind::AssocTy,
AssocKind::Existential => DefKind::AssocExistential,
}
}
/// Tests whether the associated item admits a non-trivial implementation
/// for !
pub fn relevant_for_never(&self) -> bool {
match self.kind {
AssocKind::Existential |
AssocKind::Const |
AssocKind::Type => true,
// FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
AssocKind::Method => !self.method_has_self_argument,
}
}
pub fn signature(&self, tcx: TyCtxt<'_>) -> String {
match self.kind {
ty::AssocKind::Method => {
// We skip the binder here because the binder would deanonymize all
// late-bound regions, and we don't want method signatures to show up
// `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
// regions just fine, showing `fn(&MyType)`.
tcx.fn_sig(self.def_id).skip_binder().to_string()
}
ty::AssocKind::Type => format!("type {};", self.ident),
ty::AssocKind::Existential => format!("existential type {};", self.ident),
ty::AssocKind::Const => {
format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id))
}
}
}
}
#[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable, HashStable)]
pub enum Visibility {
/// Visible everywhere (including in other crates).
Public,
/// Visible only in the given crate-local module.
Restricted(DefId),
/// Not visible anywhere in the local crate. This is the visibility of private external items.
Invisible,
}
pub trait DefIdTree: Copy {
fn parent(self, id: DefId) -> Option<DefId>;
fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
if descendant.krate != ancestor.krate {
return false;
}
while descendant != ancestor {
match self.parent(descendant) {
Some(parent) => descendant = parent,
None => return false,
}
}
true
}
}
impl<'tcx> DefIdTree for TyCtxt<'tcx> {
fn parent(self, id: DefId) -> Option<DefId> {
self.def_key(id).parent.map(|index| DefId { index: index, ..id })
}
}
impl Visibility {
pub fn from_hir(visibility: &hir::Visibility, id: hir::HirId, tcx: TyCtxt<'_>) -> Self {
match visibility.node {
hir::VisibilityKind::Public => Visibility::Public,
hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
hir::VisibilityKind::Restricted { ref path, .. } => match path.res {
// If there is no resolution, `resolve` will have already reported an error, so
// assume that the visibility is public to avoid reporting more privacy errors.
Res::Err => Visibility::Public,
def => Visibility::Restricted(def.def_id()),
},
hir::VisibilityKind::Inherited => {
Visibility::Restricted(tcx.hir().get_module_parent(id))
}
}
}
/// Returns `true` if an item with this visibility is accessible from the given block.
pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
let restriction = match self {
// Public items are visible everywhere.
Visibility::Public => return true,
// Private items from other crates are visible nowhere.
Visibility::Invisible => return false,
// Restricted items are visible in an arbitrary local module.
Visibility::Restricted(other) if other.krate != module.krate => return false,
Visibility::Restricted(module) => module,
};
tree.is_descendant_of(module, restriction)
}
/// Returns `true` if this visibility is at least as accessible as the given visibility
pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
let vis_restriction = match vis {
Visibility::Public => return self == Visibility::Public,
Visibility::Invisible => return true,
Visibility::Restricted(module) => module,
};
self.is_accessible_from(vis_restriction, tree)
}
// Returns `true` if this item is visible anywhere in the local crate.
pub fn is_visible_locally(self) -> bool {
match self {
Visibility::Public => true,
Visibility::Restricted(def_id) => def_id.is_local(),
Visibility::Invisible => false,
}
}
}
#[derive(Copy, Clone, PartialEq, Eq, RustcDecodable, RustcEncodable, Hash, HashStable)]
pub enum Variance {
Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
}
/// The crate variances map is computed during typeck and contains the
/// variance of every item in the local crate. You should not use it
/// directly, because to do so will make your pass dependent on the
/// HIR of every item in the local crate. Instead, use
/// `tcx.variances_of()` to get the variance for a *particular*
/// item.
#[derive(HashStable)]
pub struct CrateVariancesMap<'tcx> {
/// For each item with generics, maps to a vector of the variance
/// of its generics. If an item has no generics, it will have no
/// entry.
pub variances: FxHashMap<DefId, &'tcx [ty::Variance]>,
}
impl Variance {
/// `a.xform(b)` combines the variance of a context with the
/// variance of a type with the following meaning. If we are in a
/// context with variance `a`, and we encounter a type argument in
/// a position with variance `b`, then `a.xform(b)` is the new
/// variance with which the argument appears.
///
/// Example 1:
///
/// *mut Vec<i32>
///
/// Here, the "ambient" variance starts as covariant. `*mut T` is
/// invariant with respect to `T`, so the variance in which the
/// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
/// yields `Invariant`. Now, the type `Vec<T>` is covariant with
/// respect to its type argument `T`, and hence the variance of
/// the `i32` here is `Invariant.xform(Covariant)`, which results
/// (again) in `Invariant`.
///
/// Example 2:
///
/// fn(*const Vec<i32>, *mut Vec<i32)
///
/// The ambient variance is covariant. A `fn` type is
/// contravariant with respect to its parameters, so the variance
/// within which both pointer types appear is
/// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
/// T` is covariant with respect to `T`, so the variance within
/// which the first `Vec<i32>` appears is
/// `Contravariant.xform(Covariant)` or `Contravariant`. The same
/// is true for its `i32` argument. In the `*mut T` case, the
/// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
/// and hence the outermost type is `Invariant` with respect to
/// `Vec<i32>` (and its `i32` argument).
///
/// Source: Figure 1 of "Taming the Wildcards:
/// Combining Definition- and Use-Site Variance" published in PLDI'11.
pub fn xform(self, v: ty::Variance) -> ty::Variance {
match (self, v) {
// Figure 1, column 1.
(ty::Covariant, ty::Covariant) => ty::Covariant,
(ty::Covariant, ty::Contravariant) => ty::Contravariant,
(ty::Covariant, ty::Invariant) => ty::Invariant,
(ty::Covariant, ty::Bivariant) => ty::Bivariant,
// Figure 1, column 2.
(ty::Contravariant, ty::Covariant) => ty::Contravariant,
(ty::Contravariant, ty::Contravariant) => ty::Covariant,
(ty::Contravariant, ty::Invariant) => ty::Invariant,
(ty::Contravariant, ty::Bivariant) => ty::Bivariant,
// Figure 1, column 3.
(ty::Invariant, _) => ty::Invariant,
// Figure 1, column 4.
(ty::Bivariant, _) => ty::Bivariant,
}
}
}
// Contains information needed to resolve types and (in the future) look up
// the types of AST nodes.
#[derive(Copy, Clone, PartialEq, Eq, Hash)]
pub struct CReaderCacheKey {
pub cnum: CrateNum,
pub pos: usize,
}
// Flags that we track on types. These flags are propagated upwards
// through the type during type construction, so that we can quickly
// check whether the type has various kinds of types in it without
// recursing over the type itself.
bitflags! {
pub struct TypeFlags: u32 {
const HAS_PARAMS = 1 << 0;
const HAS_SELF = 1 << 1;
const HAS_TY_INFER = 1 << 2;
const HAS_RE_INFER = 1 << 3;
const HAS_RE_PLACEHOLDER = 1 << 4;
/// Does this have any `ReEarlyBound` regions? Used to
/// determine whether substitition is required, since those
/// represent regions that are bound in a `ty::Generics` and
/// hence may be substituted.
const HAS_RE_EARLY_BOUND = 1 << 5;
/// Does this have any region that "appears free" in the type?
/// Basically anything but `ReLateBound` and `ReErased`.
const HAS_FREE_REGIONS = 1 << 6;
/// Is an error type reachable?
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_FREE_LOCAL_NAMES = 1 << 10;
/// Present if the type belongs in a local type context.
/// Only set for Infer 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;
/// Does this have any `ReLateBound` regions? Used to check
/// if a global bound is safe to evaluate.
const HAS_RE_LATE_BOUND = 1 << 13;
const HAS_TY_PLACEHOLDER = 1 << 14;
const HAS_CT_INFER = 1 << 15;
const HAS_CT_PLACEHOLDER = 1 << 16;
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_CT_INFER.bits |
TypeFlags::HAS_RE_PLACEHOLDER.bits |
TypeFlags::HAS_RE_EARLY_BOUND.bits |
TypeFlags::HAS_FREE_REGIONS.bits |
TypeFlags::HAS_TY_ERR.bits |
TypeFlags::HAS_PROJECTION.bits |
TypeFlags::HAS_TY_CLOSURE.bits |
TypeFlags::HAS_FREE_LOCAL_NAMES.bits |
TypeFlags::KEEP_IN_LOCAL_TCX.bits |
TypeFlags::HAS_RE_LATE_BOUND.bits |
TypeFlags::HAS_TY_PLACEHOLDER.bits |
TypeFlags::HAS_CT_PLACEHOLDER.bits;
}
}
#[cfg_attr(not(bootstrap), allow(rustc::usage_of_ty_tykind))]
pub struct TyS<'tcx> {
pub sty: TyKind<'tcx>,
pub flags: TypeFlags,
/// This is a kind of confusing thing: it stores the smallest
/// binder such that
///
/// (a) the binder itself captures nothing but
/// (b) all the late-bound things within the type are captured
/// by some sub-binder.
///
/// So, for a type without any late-bound things, like `u32`, this
/// will be *innermost*, because that is the innermost binder that
/// captures nothing. But for a type `&'D u32`, where `'D` is a
/// late-bound region with De Bruijn index `D`, this would be `D + 1`
/// -- the binder itself does not capture `D`, but `D` is captured
/// by an inner binder.
///
/// We call this concept an "exclusive" binder `D` because all
/// De Bruijn indices within the type are contained within `0..D`
/// (exclusive).
outer_exclusive_binder: ty::DebruijnIndex,
}
// `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
#[cfg(target_arch = "x86_64")]
static_assert_size!(TyS<'_>, 32);
impl<'tcx> Ord for TyS<'tcx> {
fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
self.sty.cmp(&other.sty)
}
}
impl<'tcx> PartialOrd for TyS<'tcx> {
fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
Some(self.sty.cmp(&other.sty))
}
}
impl<'tcx> PartialEq for TyS<'tcx> {
#[inline]
fn eq(&self, other: &TyS<'tcx>) -> bool {
ptr::eq(self, other)
}
}
impl<'tcx> Eq for TyS<'tcx> {}
impl<'tcx> Hash for TyS<'tcx> {
fn hash<H: Hasher>(&self, s: &mut H) {
(self as *const TyS<'_>).hash(s)
}
}
impl<'tcx> TyS<'tcx> {
pub fn is_primitive_ty(&self) -> bool {
match self.sty {
Bool |
Char |
Int(_) |
Uint(_) |
Float(_) |
Infer(InferTy::IntVar(_)) |
Infer(InferTy::FloatVar(_)) |
Infer(InferTy::FreshIntTy(_)) |
Infer(InferTy::FreshFloatTy(_)) => true,
Ref(_, x, _) => x.is_primitive_ty(),
_ => false,
}
}
pub fn is_suggestable(&self) -> bool {
match self.sty {
Opaque(..) |
FnDef(..) |
FnPtr(..) |
Dynamic(..) |
Closure(..) |
Infer(..) |
Projection(..) => false,
_ => true,
}
}
}
impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ty::TyS<'tcx> {
fn hash_stable<W: StableHasherResult>(&self,
hcx: &mut StableHashingContext<'a>,
hasher: &mut StableHasher<W>) {
let ty::TyS {
ref sty,
// The other fields just provide fast access to information that is
// also contained in `sty`, so no need to hash them.
flags: _,
outer_exclusive_binder: _,
} = *self;
sty.hash_stable(hcx, hasher);
}
}
pub type Ty<'tcx> = &'tcx TyS<'tcx>;
impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
pub type CanonicalTy<'tcx> = Canonical<'tcx, Ty<'tcx>>;
extern {
/// A dummy type used to force List to by unsized without requiring fat pointers
type OpaqueListContents;
}
/// A wrapper for slices with the additional invariant
/// that the slice is interned and no other slice with
/// the same contents can exist in the same context.
/// This means we can use pointer for both
/// equality comparisons and hashing.
/// Note: `Slice` was already taken by the `Ty`.
#[repr(C)]
pub struct List<T> {
len: usize,
data: [T; 0],
opaque: OpaqueListContents,
}
unsafe impl<T: Sync> Sync for List<T> {}
impl<T: Copy> List<T> {
#[inline]
fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx List<T> {
assert!(!mem::needs_drop::<T>());
assert!(mem::size_of::<T>() != 0);
assert!(slice.len() != 0);
// Align up the size of the len (usize) field
let align = mem::align_of::<T>();
let align_mask = align - 1;
let offset = mem::size_of::<usize>();
let offset = (offset + align_mask) & !align_mask;
let size = offset + slice.len() * mem::size_of::<T>();
let mem = arena.alloc_raw(
size,
cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
unsafe {
let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
// Write the length
result.len = slice.len();
// Write the elements
let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
arena_slice.copy_from_slice(slice);
result
}
}
}
impl<T: fmt::Debug> fmt::Debug for List<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
(**self).fmt(f)
}
}
impl<T: Encodable> Encodable for List<T> {
#[inline]
fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
(**self).encode(s)
}
}
impl<T> Ord for List<T> where T: Ord {
fn cmp(&self, other: &List<T>) -> Ordering {
if self == other { Ordering::Equal } else {
<[T] as Ord>::cmp(&**self, &**other)
}
}
}
impl<T> PartialOrd for List<T> where T: PartialOrd {
fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> {
if self == other { Some(Ordering::Equal) } else {
<[T] as PartialOrd>::partial_cmp(&**self, &**other)
}
}
}
impl<T: PartialEq> PartialEq for List<T> {
#[inline]
fn eq(&self, other: &List<T>) -> bool {
ptr::eq(self, other)
}
}
impl<T: Eq> Eq for List<T> {}
impl<T> Hash for List<T> {
#[inline]
fn hash<H: Hasher>(&self, s: &mut H) {
(self as *const List<T>).hash(s)
}
}
impl<T> Deref for List<T> {
type Target = [T];
#[inline(always)]
fn deref(&self) -> &[T] {
unsafe {
slice::from_raw_parts(self.data.as_ptr(), self.len)
}
}
}
impl<'a, T> IntoIterator for &'a List<T> {
type Item = &'a T;
type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
#[inline(always)]
fn into_iter(self) -> Self::IntoIter {
self[..].iter()
}
}
impl<'tcx> serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
impl<T> List<T> {
#[inline(always)]
pub fn empty<'a>() -> &'a List<T> {
#[repr(align(64), C)]
struct EmptySlice([u8; 64]);
static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
assert!(mem::align_of::<T>() <= 64);
unsafe {
&*(&EMPTY_SLICE as *const _ as *const List<T>)
}
}
}
#[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
pub struct UpvarPath {
pub hir_id: hir::HirId,
}
/// Upvars do not get their own `NodeId`. Instead, we use the pair of
/// the original var ID (that is, the root variable that is referenced
/// by the upvar) and the ID of the closure expression.
#[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
pub struct UpvarId {
pub var_path: UpvarPath,
pub closure_expr_id: LocalDefId,
}
#[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy, HashStable)]
pub enum BorrowKind {
/// Data must be immutable and is aliasable.
ImmBorrow,
/// Data must be immutable but not aliasable. This kind of borrow
/// cannot currently be expressed by the user and is used only in
/// implicit closure bindings. It is needed when the closure
/// is borrowing or mutating a mutable referent, e.g.:
///
/// let x: &mut isize = ...;
/// let y = || *x += 5;
///
/// If we were to try to translate this closure into a more explicit
/// form, we'd encounter an error with the code as written:
///
/// struct Env { x: & &mut isize }
/// let x: &mut isize = ...;
/// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
/// fn fn_ptr(env: &mut Env) { **env.x += 5; }
///
/// This is then illegal because you cannot mutate a `&mut` found
/// in an aliasable location. To solve, you'd have to translate with
/// an `&mut` borrow:
///
/// struct Env { x: & &mut isize }
/// let x: &mut isize = ...;
/// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
/// fn fn_ptr(env: &mut Env) { **env.x += 5; }
///
/// Now the assignment to `**env.x` is legal, but creating a
/// mutable pointer to `x` is not because `x` is not mutable. We
/// could fix this by declaring `x` as `let mut x`. This is ok in
/// user code, if awkward, but extra weird for closures, since the
/// borrow is hidden.
///
/// So we introduce a "unique imm" borrow -- the referent is
/// immutable, but not aliasable. This solves the problem. For
/// simplicity, we don't give users the way to express this
/// borrow, it's just used when translating closures.
UniqueImmBorrow,
/// Data is mutable and not aliasable.
MutBorrow
}
/// Information describing the capture of an upvar. This is computed
/// during `typeck`, specifically by `regionck`.
#[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable, HashStable)]
pub enum UpvarCapture<'tcx> {
/// Upvar is captured by value. This is always true when the
/// closure is labeled `move`, but can also be true in other cases
/// depending on inference.
ByValue,
/// Upvar is captured by reference.
ByRef(UpvarBorrow<'tcx>),
}
#[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable, HashStable)]
pub struct UpvarBorrow<'tcx> {
/// The kind of borrow: by-ref upvars have access to shared
/// immutable borrows, which are not part of the normal language
/// syntax.
pub kind: BorrowKind,
/// Region of the resulting reference.
pub region: ty::Region<'tcx>,
}
pub type UpvarListMap = FxHashMap<DefId, FxIndexMap<hir::HirId, UpvarId>>;
pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
#[derive(Copy, Clone)]
pub struct ClosureUpvar<'tcx> {
pub res: Res,
pub span: Span,
pub ty: Ty<'tcx>,
}
#[derive(Clone, Copy, PartialEq, Eq)]
pub enum IntVarValue {
IntType(ast::IntTy),
UintType(ast::UintTy),
}
#[derive(Clone, Copy, PartialEq, Eq)]
pub struct FloatVarValue(pub ast::FloatTy);
impl ty::EarlyBoundRegion {
pub fn to_bound_region(&self) -> ty::BoundRegion {
ty::BoundRegion::BrNamed(self.def_id, self.name)
}
/// Does this early bound region have a name? Early bound regions normally
/// always have names except when using anonymous lifetimes (`'_`).
pub fn has_name(&self) -> bool {
self.name != kw::UnderscoreLifetime.as_interned_str()
}
}
#[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
pub enum GenericParamDefKind {
Lifetime,
Type {
has_default: bool,
object_lifetime_default: ObjectLifetimeDefault,
synthetic: Option<hir::SyntheticTyParamKind>,
},
Const,
}
#[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
pub struct GenericParamDef {
pub name: InternedString,
pub def_id: DefId,
pub index: u32,
/// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
/// on generic parameter `'a`/`T`, asserts data behind the parameter
/// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
pub pure_wrt_drop: bool,
pub kind: GenericParamDefKind,
}
impl GenericParamDef {
pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
if let GenericParamDefKind::Lifetime = self.kind {
ty::EarlyBoundRegion {
def_id: self.def_id,
index: self.index,
name: self.name,
}
} else {
bug!("cannot convert a non-lifetime parameter def to an early bound region")
}
}
pub fn to_bound_region(&self) -> ty::BoundRegion {
if let GenericParamDefKind::Lifetime = self.kind {
self.to_early_bound_region_data().to_bound_region()
} else {
bug!("cannot convert a non-lifetime parameter def to an early bound region")
}
}
}
#[derive(Default)]
pub struct GenericParamCount {
pub lifetimes: usize,
pub types: usize,
pub consts: usize,
}
/// Information about the formal type/lifetime parameters associated
/// with an item or method. Analogous to `hir::Generics`.
///
/// The ordering of parameters is the same as in `Subst` (excluding child generics):
/// `Self` (optionally), `Lifetime` params..., `Type` params...
#[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
pub struct Generics {
pub parent: Option<DefId>,
pub parent_count: usize,
pub params: Vec<GenericParamDef>,
/// Reverse map to the `index` field of each `GenericParamDef`
#[stable_hasher(ignore)]
pub param_def_id_to_index: FxHashMap<DefId, u32>,
pub has_self: bool,
pub has_late_bound_regions: Option<Span>,
}
impl<'tcx> Generics {
pub fn count(&self) -> usize {
self.parent_count + self.params.len()
}
pub fn own_counts(&self) -> GenericParamCount {
// We could cache this as a property of `GenericParamCount`, but
// the aim is to refactor this away entirely eventually and the
// presence of this method will be a constant reminder.
let mut own_counts: GenericParamCount = Default::default();
for param in &self.params {
match param.kind {
GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
GenericParamDefKind::Type { .. } => own_counts.types += 1,
GenericParamDefKind::Const => own_counts.consts += 1,
};
}
own_counts
}
pub fn requires_monomorphization(&self, tcx: TyCtxt<'tcx>) -> bool {
if self.own_requires_monomorphization() {
return true;
}
if let Some(parent_def_id) = self.parent {
let parent = tcx.generics_of(parent_def_id);
parent.requires_monomorphization(tcx)
} else {
false
}
}
pub fn own_requires_monomorphization(&self) -> bool {
for param in &self.params {
match param.kind {
GenericParamDefKind::Type { .. } | GenericParamDefKind::Const => return true,
GenericParamDefKind::Lifetime => {}
}
}
false
}
pub fn region_param(
&'tcx self,
param: &EarlyBoundRegion,
tcx: TyCtxt<'tcx>,
) -> &'tcx GenericParamDef {
if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
let param = &self.params[index as usize];
match param.kind {
GenericParamDefKind::Lifetime => param,
_ => bug!("expected lifetime parameter, but found another generic parameter")
}
} else {
tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
.region_param(param, tcx)
}
}
/// Returns the `GenericParamDef` associated with this `ParamTy`.
pub fn type_param(&'tcx self, param: &ParamTy, tcx: TyCtxt<'tcx>) -> &'tcx GenericParamDef {
if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
let param = &self.params[index as usize];
match param.kind {
GenericParamDefKind::Type { .. } => param,
_ => bug!("expected type parameter, but found another generic parameter")
}
} else {
tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
.type_param(param, tcx)
}
}
/// Returns the `ConstParameterDef` associated with this `ParamConst`.
pub fn const_param(&'tcx self, param: &ParamConst, tcx: TyCtxt<'tcx>) -> &GenericParamDef {
if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
let param = &self.params[index as usize];
match param.kind {
GenericParamDefKind::Const => param,
_ => bug!("expected const parameter, but found another generic parameter")
}
} else {
tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
.const_param(param, tcx)
}
}
}
/// Bounds on generics.
#[derive(Clone, Default, Debug, HashStable)]
pub struct GenericPredicates<'tcx> {
pub parent: Option<DefId>,
pub predicates: Vec<(Predicate<'tcx>, Span)>,
}
impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
impl<'tcx> GenericPredicates<'tcx> {
pub fn instantiate(
&self,
tcx: TyCtxt<'tcx>,
substs: SubstsRef<'tcx>,
) -> InstantiatedPredicates<'tcx> {
let mut instantiated = InstantiatedPredicates::empty();
self.instantiate_into(tcx, &mut instantiated, substs);
instantiated
}
pub fn instantiate_own(
&self,
tcx: TyCtxt<'tcx>,
substs: SubstsRef<'tcx>,
) -> InstantiatedPredicates<'tcx> {
InstantiatedPredicates {
predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
}
}
fn instantiate_into(
&self,
tcx: TyCtxt<'tcx>,
instantiated: &mut InstantiatedPredicates<'tcx>,
substs: SubstsRef<'tcx>,
) {
if let Some(def_id) = self.parent {
tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
}
instantiated.predicates.extend(
self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)),
);
}
pub fn instantiate_identity(&self, tcx: TyCtxt<'tcx>) -> InstantiatedPredicates<'tcx> {
let mut instantiated = InstantiatedPredicates::empty();
self.instantiate_identity_into(tcx, &mut instantiated);
instantiated
}
fn instantiate_identity_into(
&self,
tcx: TyCtxt<'tcx>,
instantiated: &mut InstantiatedPredicates<'tcx>,
) {
if let Some(def_id) = self.parent {
tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
}
instantiated.predicates.extend(self.predicates.iter().map(|&(p, _)| p))
}
pub fn instantiate_supertrait(
&self,
tcx: TyCtxt<'tcx>,
poly_trait_ref: &ty::PolyTraitRef<'tcx>,
) -> InstantiatedPredicates<'tcx> {
assert_eq!(self.parent, None);
InstantiatedPredicates {
predicates: self.predicates.iter().map(|(pred, _)| {
pred.subst_supertrait(tcx, poly_trait_ref)
}).collect()
}
}
}
#[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
pub enum Predicate<'tcx> {
/// Corresponds to `where Foo: Bar<A, B, C>`. `Foo` here would be
/// the `Self` type of the trait reference and `A`, `B`, and `C`
/// would be the type parameters.
Trait(PolyTraitPredicate<'tcx>),
/// `where 'a: 'b`
RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
/// `where T: 'a`
TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
/// `where <T as TraitRef>::Name == X`, approximately.
/// See the `ProjectionPredicate` struct for details.
Projection(PolyProjectionPredicate<'tcx>),
/// No syntax: `T` well-formed.
WellFormed(Ty<'tcx>),
/// Trait must be object-safe.
ObjectSafe(DefId),
/// No direct syntax. May be thought of as `where T: FnFoo<...>`
/// for some substitutions `...` and `T` being a closure type.
/// Satisfied (or refuted) once we know the closure's kind.
ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
/// `T1 <: T2`
Subtype(PolySubtypePredicate<'tcx>),
/// Constant initializer must evaluate successfully.
ConstEvaluatable(DefId, SubstsRef<'tcx>),
}
/// The crate outlives map is computed during typeck and contains the
/// outlives of every item in the local crate. You should not use it
/// directly, because to do so will make your pass dependent on the
/// HIR of every item in the local crate. Instead, use
/// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
/// item.
#[derive(HashStable)]
pub struct CratePredicatesMap<'tcx> {
/// For each struct with outlive bounds, maps to a vector of the
/// predicate of its outlive bounds. If an item has no outlives
/// bounds, it will have no entry.
pub predicates: FxHashMap<DefId, &'tcx [ty::Predicate<'tcx>]>,
}
impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
fn as_ref(&self) -> &Predicate<'tcx> {
self
}
}
impl<'tcx> Predicate<'tcx> {
/// Performs a substitution suitable for going from a
/// poly-trait-ref to supertraits that must hold if that
/// poly-trait-ref holds. This is slightly different from a normal
/// substitution in terms of what happens with bound regions. See
/// lengthy comment below for details.
pub fn subst_supertrait(
&self,
tcx: TyCtxt<'tcx>,
trait_ref: &ty::PolyTraitRef<'tcx>,
) -> ty::Predicate<'tcx> {
// The interaction between HRTB and supertraits is not entirely
// obvious. Let me walk you (and myself) through an example.
//
// Let's start with an easy case. Consider two traits:
//
// trait Foo<'a>: Bar<'a,'a> { }
// trait Bar<'b,'c> { }
//
// Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
// we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
// knew that `Foo<'x>` (for any 'x) then we also know that
// `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
// normal substitution.
//
// In terms of why this is sound, the idea is that whenever there
// is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
// holds. So if there is an impl of `T:Foo<'a>` that applies to
// all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
// `'a`.
//
// Another example to be careful of is this:
//
// trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
// trait Bar1<'b,'c> { }
//
// Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
// The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
// reason is similar to the previous example: any impl of
// `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
// basically we would want to collapse the bound lifetimes from
// the input (`trait_ref`) and the supertraits.
//
// To achieve this in practice is fairly straightforward. Let's
// consider the more complicated scenario:
//
// - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
// has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
// where both `'x` and `'b` would have a DB index of 1.
// The substitution from the input trait-ref is therefore going to be
// `'a => 'x` (where `'x` has a DB index of 1).
// - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
// early-bound parameter and `'b' is a late-bound parameter with a
// DB index of 1.
// - If we replace `'a` with `'x` from the input, it too will have
// a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
// just as we wanted.
//
// There is only one catch. If we just apply the substitution `'a
// => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
// adjust the DB index because we substituting into a binder (it
// tries to be so smart...) resulting in `for<'x> for<'b>
// Bar1<'x,'b>` (we have no syntax for this, so use your
// imagination). Basically the 'x will have DB index of 2 and 'b
// will have DB index of 1. Not quite what we want. So we apply
// the substitution to the *contents* of the trait reference,
// rather than the trait reference itself (put another way, the
// substitution code expects equal binding levels in the values
// from the substitution and the value being substituted into, and
// this trick achieves that).
let substs = &trait_ref.skip_binder().substs;
match *self {
Predicate::Trait(ref binder) =>
Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
Predicate::Subtype(ref binder) =>
Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
Predicate::RegionOutlives(ref binder) =>
Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
Predicate::TypeOutlives(ref binder) =>
Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
Predicate::Projection(ref binder) =>
Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
Predicate::WellFormed(data) =>
Predicate::WellFormed(data.subst(tcx, substs)),
Predicate::ObjectSafe(trait_def_id) =>
Predicate::ObjectSafe(trait_def_id),
Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
Predicate::ConstEvaluatable(def_id, const_substs) =>
Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
}
}
}
#[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
pub struct TraitPredicate<'tcx> {
pub trait_ref: TraitRef<'tcx>
}
pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
impl<'tcx> TraitPredicate<'tcx> {
pub fn def_id(&self) -> DefId {
self.trait_ref.def_id
}
pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item = Ty<'tcx>> + 'a {
self.trait_ref.input_types()
}
pub fn self_ty(&self) -> Ty<'tcx> {
self.trait_ref.self_ty()
}
}
impl<'tcx> PolyTraitPredicate<'tcx> {
pub fn def_id(&self) -> DefId {
// Ok to skip binder since trait def-ID does not care about regions.
self.skip_binder().def_id()
}
}
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord,
Hash, Debug, RustcEncodable, RustcDecodable, HashStable)]
pub struct OutlivesPredicate<A, B>(pub A, pub B); // `A: B`
pub type PolyOutlivesPredicate<A, B> = ty::Binder<OutlivesPredicate<A, B>>;
pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>;
pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, HashStable)]
pub struct SubtypePredicate<'tcx> {
pub a_is_expected: bool,
pub a: Ty<'tcx>,
pub b: Ty<'tcx>
}
pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
/// This kind of predicate has no *direct* correspondent in the
/// syntax, but it roughly corresponds to the syntactic forms:
///
/// 1. `T: TraitRef<..., Item = Type>`
/// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
///
/// In particular, form #1 is "desugared" to the combination of a
/// normal trait predicate (`T: TraitRef<...>`) and one of these
/// predicates. Form #2 is a broader form in that it also permits
/// equality between arbitrary types. Processing an instance of
/// Form #2 eventually yields one of these `ProjectionPredicate`
/// instances to normalize the LHS.
#[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
pub struct ProjectionPredicate<'tcx> {
pub projection_ty: ProjectionTy<'tcx>,
pub ty: Ty<'tcx>,
}
pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
impl<'tcx> PolyProjectionPredicate<'tcx> {
/// Returns the `DefId` of the associated item being projected.
pub fn item_def_id(&self) -> DefId {
self.skip_binder().projection_ty.item_def_id
}
#[inline]
pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'_>) -> PolyTraitRef<'tcx> {
// Note: unlike with `TraitRef::to_poly_trait_ref()`,
// `self.0.trait_ref` is permitted to have escaping regions.
// This is because here `self` has a `Binder` and so does our
// return value, so we are preserving the number of binding
// levels.
self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
}
pub fn ty(&self) -> Binder<Ty<'tcx>> {
self.map_bound(|predicate| predicate.ty)
}
/// The `DefId` of the `TraitItem` for the associated type.
///
/// Note that this is not the `DefId` of the `TraitRef` containing this
/// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
pub fn projection_def_id(&self) -> DefId {
// Ok to skip binder since trait def-ID does not care about regions.
self.skip_binder().projection_ty.item_def_id
}
}
pub trait ToPolyTraitRef<'tcx> {
fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
}
impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
ty::Binder::dummy(self.clone())
}
}
impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
}
}
pub trait ToPredicate<'tcx> {
fn to_predicate(&self) -> Predicate<'tcx>;
}
impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
fn to_predicate(&self) -> Predicate<'tcx> {
ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
trait_ref: self.clone()
}))
}
}
impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
fn to_predicate(&self) -> Predicate<'tcx> {
ty::Predicate::Trait(self.to_poly_trait_predicate())
}
}
impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
fn to_predicate(&self) -> Predicate<'tcx> {
Predicate::RegionOutlives(self.clone())
}
}
impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
fn to_predicate(&self) -> Predicate<'tcx> {
Predicate::TypeOutlives(self.clone())
}
}
impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
fn to_predicate(&self) -> Predicate<'tcx> {
Predicate::Projection(self.clone())
}
}
// A custom iterator used by `Predicate::walk_tys`.
enum WalkTysIter<'tcx, I, J, K>
where I: Iterator<Item = Ty<'tcx>>,
J: Iterator<Item = Ty<'tcx>>,
K: Iterator<Item = Ty<'tcx>>
{
None,
One(Ty<'tcx>),
Two(Ty<'tcx>, Ty<'tcx>),
Types(I),
InputTypes(J),
ProjectionTypes(K)
}
impl<'tcx, I, J, K> Iterator for WalkTysIter<'tcx, I, J, K>
where I: Iterator<Item = Ty<'tcx>>,
J: Iterator<Item = Ty<'tcx>>,
K: Iterator<Item = Ty<'tcx>>
{
type Item = Ty<'tcx>;
fn next(&mut self) -> Option<Ty<'tcx>> {
match *self {
WalkTysIter::None => None,
WalkTysIter::One(item) => {
*self = WalkTysIter::None;
Some(item)
},
WalkTysIter::Two(item1, item2) => {
*self = WalkTysIter::One(item2);
Some(item1)
},
WalkTysIter::Types(ref mut iter) => {
iter.next()
},
WalkTysIter::InputTypes(ref mut iter) => {
iter.next()
},
WalkTysIter::ProjectionTypes(ref mut iter) => {
iter.next()
}
}
}
}
impl<'tcx> Predicate<'tcx> {
/// Iterates over the types in this predicate. Note that in all
/// cases this is skipping over a binder, so late-bound regions
/// with depth 0 are bound by the predicate.
pub fn walk_tys(&'a self) -> impl Iterator<Item = Ty<'tcx>> + 'a {
match *self {
ty::Predicate::Trait(ref data) => {
WalkTysIter::InputTypes(data.skip_binder().input_types())
}
ty::Predicate::Subtype(binder) => {
let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
WalkTysIter::Two(a, b)
}
ty::Predicate::TypeOutlives(binder) => {
WalkTysIter::One(binder.skip_binder().0)
}
ty::Predicate::RegionOutlives(..) => {
WalkTysIter::None
}
ty::Predicate::Projection(ref data) => {
let inner = data.skip_binder();
WalkTysIter::ProjectionTypes(
inner.projection_ty.substs.types().chain(Some(inner.ty)))
}
ty::Predicate::WellFormed(data) => {
WalkTysIter::One(data)
}
ty::Predicate::ObjectSafe(_trait_def_id) => {
WalkTysIter::None
}
ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
WalkTysIter::Types(closure_substs.substs.types())
}
ty::Predicate::ConstEvaluatable(_, substs) => {
WalkTysIter::Types(substs.types())
}
}
}
pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
match *self {
Predicate::Trait(ref t) => {
Some(t.to_poly_trait_ref())
}
Predicate::Projection(..) |
Predicate::Subtype(..) |
Predicate::RegionOutlives(..) |
Predicate::WellFormed(..) |
Predicate::ObjectSafe(..) |
Predicate::ClosureKind(..) |
Predicate::TypeOutlives(..) |
Predicate::ConstEvaluatable(..) => {
None
}
}
}
pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
match *self {
Predicate::TypeOutlives(data) => {
Some(data)
}
Predicate::Trait(..) |
Predicate::Projection(..) |
Predicate::Subtype(..) |
Predicate::RegionOutlives(..) |
Predicate::WellFormed(..) |
Predicate::ObjectSafe(..) |
Predicate::ClosureKind(..) |
Predicate::ConstEvaluatable(..) => {
None
}
}
}
}
/// Represents the bounds declared on a particular set of type
/// parameters. Should eventually be generalized into a flag list of
/// where-clauses. You can obtain a `InstantiatedPredicates` list from a
/// `GenericPredicates` by using the `instantiate` method. Note that this method
/// reflects an important semantic invariant of `InstantiatedPredicates`: while
/// the `GenericPredicates` are expressed in terms of the bound type
/// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
/// represented a set of bounds for some particular instantiation,
/// meaning that the generic parameters have been substituted with
/// their values.
///
/// Example:
///
/// struct Foo<T, U: Bar<T>> { ... }
///
/// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
/// `[[], [U:Bar<T>]]`. Now if there were some particular reference
/// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
/// [usize:Bar<isize>]]`.
#[derive(Clone, Debug)]
pub struct InstantiatedPredicates<'tcx> {
pub predicates: Vec<Predicate<'tcx>>,
}
impl<'tcx> InstantiatedPredicates<'tcx> {
pub fn empty() -> InstantiatedPredicates<'tcx> {
InstantiatedPredicates { predicates: vec![] }
}
pub fn is_empty(&self) -> bool {
self.predicates.is_empty()
}
}
newtype_index! {
/// "Universes" are used during type- and trait-checking in the
/// presence of `for<..>` binders to control what sets of names are
/// visible. Universes are arranged into a tree: the root universe
/// contains names that are always visible. Each child then adds a new
/// set of names that are visible, in addition to those of its parent.
/// We say that the child universe "extends" the parent universe with
/// new names.
///
/// To make this more concrete, consider this program:
///
/// ```
/// struct Foo { }
/// fn bar<T>(x: T) {
/// let y: for<'a> fn(&'a u8, Foo) = ...;
/// }
/// ```
///
/// The struct name `Foo` is in the root universe U0. But the type
/// parameter `T`, introduced on `bar`, is in an extended universe U1
/// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
/// of `bar`, we cannot name `T`. Then, within the type of `y`, the
/// region `'a` is in a universe U2 that extends U1, because we can
/// name it inside the fn type but not outside.
///
/// Universes are used to do type- and trait-checking around these
/// "forall" binders (also called **universal quantification**). The
/// idea is that when, in the body of `bar`, we refer to `T` as a
/// type, we aren't referring to any type in particular, but rather a
/// kind of "fresh" type that is distinct from all other types we have
/// actually declared. This is called a **placeholder** type, and we
/// use universes to talk about this. In other words, a type name in
/// universe 0 always corresponds to some "ground" type that the user
/// declared, but a type name in a non-zero universe is a placeholder
/// type -- an idealized representative of "types in general" that we
/// use for checking generic functions.
pub struct UniverseIndex {
DEBUG_FORMAT = "U{}",
}
}
impl_stable_hash_for!(struct UniverseIndex { private });
impl UniverseIndex {
pub const ROOT: UniverseIndex = UniverseIndex::from_u32_const(0);
/// Returns the "next" universe index in order -- this new index
/// is considered to extend all previous universes. This
/// corresponds to entering a `forall` quantifier. So, for
/// example, suppose we have this type in universe `U`:
///
/// ```
/// for<'a> fn(&'a u32)
/// ```
///
/// Once we "enter" into this `for<'a>` quantifier, we are in a
/// new universe that extends `U` -- in this new universe, we can
/// name the region `'a`, but that region was not nameable from
/// `U` because it was not in scope there.
pub fn next_universe(self) -> UniverseIndex {
UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
}
/// Returns `true` if `self` can name a name from `other` -- in other words,
/// if the set of names in `self` is a superset of those in
/// `other` (`self >= other`).
pub fn can_name(self, other: UniverseIndex) -> bool {
self.private >= other.private
}
/// Returns `true` if `self` cannot name some names from `other` -- in other
/// words, if the set of names in `self` is a strict subset of
/// those in `other` (`self < other`).
pub fn cannot_name(self, other: UniverseIndex) -> bool {
self.private < other.private
}
}
/// The "placeholder index" fully defines a placeholder region.
/// Placeholder regions are identified by both a **universe** as well
/// as a "bound-region" within that universe. The `bound_region` is
/// basically a name -- distinct bound regions within the same
/// universe are just two regions with an unknown relationship to one
/// another.
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
pub struct Placeholder<T> {
pub universe: UniverseIndex,
pub name: T,
}
impl<'a, T> HashStable<StableHashingContext<'a>> for Placeholder<T>
where
T: HashStable<StableHashingContext<'a>>,
{
fn hash_stable<W: StableHasherResult>(
&self,
hcx: &mut StableHashingContext<'a>,
hasher: &mut StableHasher<W>
) {
self.universe.hash_stable(hcx, hasher);
self.name.hash_stable(hcx, hasher);
}
}
pub type PlaceholderRegion = Placeholder<BoundRegion>;
pub type PlaceholderType = Placeholder<BoundVar>;
pub type PlaceholderConst = Placeholder<BoundVar>;
/// When type checking, we use the `ParamEnv` to track
/// details about the set of where-clauses that are in scope at this
/// particular point.
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable)]
pub struct ParamEnv<'tcx> {
/// 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 List<ty::Predicate<'tcx>>,
/// Typically, this is `Reveal::UserFacing`, but during codegen we
/// want `Reveal::All` -- note that this is always paired with an
/// empty environment. To get that, use `ParamEnv::reveal()`.
pub reveal: traits::Reveal,
/// If this `ParamEnv` comes from a call to `tcx.param_env(def_id)`,
/// register that `def_id` (useful for transitioning to the chalk trait
/// solver).
pub def_id: Option<DefId>,
}
impl<'tcx> ParamEnv<'tcx> {
/// Construct a trait environment suitable for contexts where
/// there are no where-clauses in scope. Hidden types (like `impl
/// Trait`) are left hidden, so this is suitable for ordinary
/// type-checking.
#[inline]
pub fn empty() -> Self {
Self::new(List::empty(), Reveal::UserFacing, None)
}
/// Construct a trait environment with no where-clauses in scope
/// where the values of all `impl Trait` and other hidden types
/// are revealed. This is suitable for monomorphized, post-typeck
/// environments like codegen or doing optimizations.
///
/// N.B., if you want to have predicates in scope, use `ParamEnv::new`,
/// or invoke `param_env.with_reveal_all()`.
#[inline]
pub fn reveal_all() -> Self {
Self::new(List::empty(), Reveal::All, None)
}
/// Construct a trait environment with the given set of predicates.
#[inline]
pub fn new(
caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
reveal: Reveal,
def_id: Option<DefId>
) -> Self {
ty::ParamEnv { caller_bounds, reveal, def_id }
}
/// Returns a new parameter environment with the same clauses, but
/// which "reveals" the true results of projections in all cases
/// (even for associated types that are specializable). This is
/// the desired behavior during codegen and certain other special
/// contexts; normally though we want to use `Reveal::UserFacing`,
/// which is the default.
pub fn with_reveal_all(self) -> Self {
ty::ParamEnv { reveal: Reveal::All, ..self }
}
/// Returns this same environment but with no caller bounds.
pub fn without_caller_bounds(self) -> Self {
ty::ParamEnv { caller_bounds: List::empty(), ..self }
}
/// Creates a suitable environment in which to perform trait
/// queries on the given value. When type-checking, this is simply
/// the pair of the environment plus value. But when reveal is set to
/// All, then if `value` does not reference any type parameters, we will
/// pair it with the empty environment. This improves caching and is generally
/// invisible.
///
/// N.B., we preserve the environment when type-checking because it
/// is possible for the user to have wacky where-clauses like
/// `where Box<u32>: Copy`, which are clearly never
/// satisfiable. We generally want to behave as if they were true,
/// although the surrounding function is never reachable.
pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
match self.reveal {
Reveal::UserFacing => {
ParamEnvAnd {
param_env: self,
value,
}
}
Reveal::All => {
if value.has_placeholders()
|| value.needs_infer()
|| value.has_param_types()
|| value.has_self_ty()
{
ParamEnvAnd {
param_env: self,
value,
}
} else {
ParamEnvAnd {
param_env: self.without_caller_bounds(),
value,
}
}
}
}
}
}
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
pub struct ParamEnvAnd<'tcx, T> {
pub param_env: ParamEnv<'tcx>,
pub value: T,
}
impl<'tcx, T> ParamEnvAnd<'tcx, T> {
pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
(self.param_env, self.value)
}
}
impl<'a, 'tcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'tcx, T>
where
T: HashStable<StableHashingContext<'a>>,
{
fn hash_stable<W: StableHasherResult>(&self,
hcx: &mut StableHashingContext<'a>,
hasher: &mut StableHasher<W>) {
let ParamEnvAnd {
ref param_env,
ref value
} = *self;
param_env.hash_stable(hcx, hasher);
value.hash_stable(hcx, hasher);
}
}
#[derive(Copy, Clone, Debug, HashStable)]
pub struct Destructor {
/// The `DefId` of the destructor method
pub did: DefId,
}
bitflags! {
#[derive(HashStable)]
pub struct AdtFlags: u32 {
const NO_ADT_FLAGS = 0;
/// Indicates whether the ADT is an enum.
const IS_ENUM = 1 << 0;
/// Indicates whether the ADT is a union.
const IS_UNION = 1 << 1;
/// Indicates whether the ADT is a struct.
const IS_STRUCT = 1 << 2;
/// Indicates whether the ADT is a struct and has a constructor.
const HAS_CTOR = 1 << 3;
/// Indicates whether the type is a `PhantomData`.
const IS_PHANTOM_DATA = 1 << 4;
/// Indicates whether the type has a `#[fundamental]` attribute.
const IS_FUNDAMENTAL = 1 << 5;
/// Indicates whether the type is a `Box`.
const IS_BOX = 1 << 6;
/// Indicates whether the type is an `Arc`.
const IS_ARC = 1 << 7;
/// Indicates whether the type is an `Rc`.
const IS_RC = 1 << 8;
/// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
/// (i.e., this flag is never set unless this ADT is an enum).
const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 9;
}
}
bitflags! {
#[derive(HashStable)]
pub struct VariantFlags: u32 {
const NO_VARIANT_FLAGS = 0;
/// Indicates whether the field list of this variant is `#[non_exhaustive]`.
const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
}
}
/// Definition of a variant -- a struct's fields or a enum variant.
#[derive(Debug)]
pub struct VariantDef {
/// `DefId` that identifies the variant itself.
/// If this variant belongs to a struct or union, then this is a copy of its `DefId`.
pub def_id: DefId,
/// `DefId` that identifies the variant's constructor.
/// If this variant is a struct variant, then this is `None`.
pub ctor_def_id: Option<DefId>,
/// Variant or struct name.
pub ident: Ident,
/// Discriminant of this variant.
pub discr: VariantDiscr,
/// Fields of this variant.
pub fields: Vec<FieldDef>,
/// Type of constructor of variant.
pub ctor_kind: CtorKind,
/// Flags of the variant (e.g. is field list non-exhaustive)?
flags: VariantFlags,
/// Recovered?
pub recovered: bool,
}
impl<'tcx> VariantDef {
/// Creates a new `VariantDef`.
///
/// `variant_did` is the `DefId` that identifies the enum variant (if this `VariantDef`
/// represents an enum variant).
///
/// `ctor_did` is the `DefId` that identifies the constructor of unit or
/// tuple-variants/structs. If this is a `struct`-variant then this should be `None`.
///
/// `parent_did` is the `DefId` of the `AdtDef` representing the enum or struct that
/// owns this variant. It is used for checking if a struct has `#[non_exhaustive]` w/out having
/// to go through the redirect of checking the ctor's attributes - but compiling a small crate
/// requires loading the `AdtDef`s for all the structs in the universe (e.g., coherence for any
/// built-in trait), and we do not want to load attributes twice.
///
/// If someone speeds up attribute loading to not be a performance concern, they can
/// remove this hack and use the constructor `DefId` everywhere.
pub fn new(
tcx: TyCtxt<'tcx>,
ident: Ident,
variant_did: Option<DefId>,
ctor_def_id: Option<DefId>,
discr: VariantDiscr,
fields: Vec<FieldDef>,
ctor_kind: CtorKind,
adt_kind: AdtKind,
parent_did: DefId,
recovered: bool,
) -> Self {
debug!(
"VariantDef::new(ident = {:?}, variant_did = {:?}, ctor_def_id = {:?}, discr = {:?},
fields = {:?}, ctor_kind = {:?}, adt_kind = {:?}, parent_did = {:?})",
ident, variant_did, ctor_def_id, discr, fields, ctor_kind, adt_kind, parent_did,
);
let mut flags = VariantFlags::NO_VARIANT_FLAGS;
if adt_kind == AdtKind::Struct && tcx.has_attr(parent_did, sym::non_exhaustive) {
debug!("found non-exhaustive field list for {:?}", parent_did);
flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
} else if let Some(variant_did) = variant_did {
if tcx.has_attr(variant_did, sym::non_exhaustive) {
debug!("found non-exhaustive field list for {:?}", variant_did);
flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
}
}
VariantDef {
def_id: variant_did.unwrap_or(parent_did),
ctor_def_id,
ident,
discr,
fields,
ctor_kind,
flags,
recovered,
}
}
/// Is this field list non-exhaustive?
#[inline]
pub fn is_field_list_non_exhaustive(&self) -> bool {
self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
}
}
impl_stable_hash_for!(struct VariantDef {
def_id,
ctor_def_id,
ident -> (ident.name),
discr,
fields,
ctor_kind,
flags,
recovered
});
#[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
pub enum VariantDiscr {
/// Explicit value for this variant, i.e., `X = 123`.
/// The `DefId` corresponds to the embedded constant.
Explicit(DefId),
/// The previous variant's discriminant plus one.
/// For efficiency reasons, the distance from the
/// last `Explicit` discriminant is being stored,
/// or `0` for the first variant, if it has none.
Relative(u32),
}
#[derive(Debug, HashStable)]
pub struct FieldDef {
pub did: DefId,
#[stable_hasher(project(name))]
pub ident: Ident,
pub vis: Visibility,
}
/// The definition of an abstract data type -- a struct or enum.
///
/// These are all interned (by `intern_adt_def`) into the `adt_defs` table.
pub struct AdtDef {
/// `DefId` of the struct, enum or union item.
pub did: DefId,
/// Variants of the ADT. If this is a struct or enum, then there will be a single variant.
pub variants: IndexVec<self::layout::VariantIdx, VariantDef>,
/// Flags of the ADT (e.g. is this a struct? is this non-exhaustive?)
flags: AdtFlags,
/// Repr options provided by the user.
pub repr: ReprOptions,
}
impl PartialOrd for AdtDef {
fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
Some(self.cmp(&other))
}
}
/// There should be only one AdtDef for each `did`, therefore
/// it is fine to implement `Ord` only based on `did`.
impl Ord for AdtDef {
fn cmp(&self, other: &AdtDef) -> Ordering {
self.did.cmp(&other.did)
}
}
impl PartialEq for AdtDef {
// AdtDef are always interned and this is part of TyS equality
#[inline]
fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) }
}
impl Eq for AdtDef {}
impl Hash for AdtDef {
#[inline]
fn hash<H: Hasher>(&self, s: &mut H) {
(self as *const AdtDef).hash(s)
}
}
impl<'tcx> 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<'a> HashStable<StableHashingContext<'a>> for AdtDef {
fn hash_stable<W: StableHasherResult>(&self,
hcx: &mut StableHashingContext<'a>,
hasher: &mut StableHasher<W>) {
thread_local! {
static CACHE: RefCell<FxHashMap<usize, Fingerprint>> = Default::default();
}
let hash: Fingerprint = CACHE.with(|cache| {
let addr = self as *const AdtDef as usize;
*cache.borrow_mut().entry(addr).or_insert_with(|| {
let ty::AdtDef {
did,
ref variants,
ref flags,
ref repr,
} = *self;
let mut hasher = StableHasher::new();
did.hash_stable(hcx, &mut hasher);
variants.hash_stable(hcx, &mut hasher);
flags.hash_stable(hcx, &mut hasher);
repr.hash_stable(hcx, &mut hasher);
hasher.finish()
})
});
hash.hash_stable(hcx, hasher);
}
}
#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
pub enum AdtKind { Struct, Union, Enum }
impl Into<DataTypeKind> for AdtKind {
fn into(self) -> DataTypeKind {
match self {
AdtKind::Struct => DataTypeKind::Struct,
AdtKind::Union => DataTypeKind::Union,
AdtKind::Enum => DataTypeKind::Enum,
}
}
}
bitflags! {
#[derive(RustcEncodable, RustcDecodable, Default)]
pub struct ReprFlags: u8 {
const IS_C = 1 << 0;
const IS_SIMD = 1 << 1;
const IS_TRANSPARENT = 1 << 2;
// Internal only for now. If true, don't reorder fields.
const IS_LINEAR = 1 << 3;
// Any of these flags being set prevent field reordering optimisation.
const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
ReprFlags::IS_SIMD.bits |
ReprFlags::IS_LINEAR.bits;
}
}
impl_stable_hash_for!(struct ReprFlags {
bits
});
/// Represents the repr options provided by the user,
#[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
pub struct ReprOptions {
pub int: Option<attr::IntType>,
pub align: u32,
pub pack: u32,
pub flags: ReprFlags,
}
impl_stable_hash_for!(struct ReprOptions {
align,
pack,
int,
flags
});
impl ReprOptions {
pub fn new(tcx: TyCtxt<'_>, did: DefId) -> ReprOptions {
let mut flags = ReprFlags::empty();
let mut size = None;
let mut max_align = 0;
let mut min_pack = 0;
for attr in tcx.get_attrs(did).iter() {
for r in attr::find_repr_attrs(&tcx.sess.parse_sess, attr) {
flags.insert(match r {
attr::ReprC => ReprFlags::IS_C,
attr::ReprPacked(pack) => {
min_pack = if min_pack > 0 {
cmp::min(pack, min_pack)
} else {
pack
};
ReprFlags::empty()
},
attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
attr::ReprSimd => ReprFlags::IS_SIMD,
attr::ReprInt(i) => {
size = Some(i);
ReprFlags::empty()
},
attr::ReprAlign(align) => {
max_align = cmp::max(align, max_align);
ReprFlags::empty()
},
});
}
}
// This is here instead of layout because the choice must make it into metadata.
if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.def_path_str(did))) {
flags.insert(ReprFlags::IS_LINEAR);
}
ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
}
#[inline]
pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
#[inline]
pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
#[inline]
pub fn packed(&self) -> bool { self.pack > 0 }
#[inline]
pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
#[inline]
pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
pub fn discr_type(&self) -> attr::IntType {
self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
}
/// Returns `true` if this `#[repr()]` should inhabit "smart enum
/// layout" optimizations, such as representing `Foo<&T>` as a
/// single pointer.
pub fn inhibit_enum_layout_opt(&self) -> bool {
self.c() || self.int.is_some()
}
/// Returns `true` if this `#[repr()]` should inhibit struct field reordering
/// optimizations, such as with `repr(C)`, `repr(packed(1))`, or `repr(<int>)`.
pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
self.flags.intersects(ReprFlags::IS_UNOPTIMISABLE) || self.pack == 1 ||
self.int.is_some()
}
/// Returns `true` if this `#[repr()]` should inhibit union ABI optimisations.
pub fn inhibit_union_abi_opt(&self) -> bool {
self.c()
}
}
impl<'tcx> AdtDef {
/// Creates a new `AdtDef`.
fn new(
tcx: TyCtxt<'_>,
did: DefId,
kind: AdtKind,
variants: IndexVec<VariantIdx, VariantDef>,
repr: ReprOptions,
) -> Self {
debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
let mut flags = AdtFlags::NO_ADT_FLAGS;
if kind == AdtKind::Enum && tcx.has_attr(did, sym::non_exhaustive) {
debug!("found non-exhaustive variant list for {:?}", did);
flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
}
flags |= match kind {
AdtKind::Enum => AdtFlags::IS_ENUM,
AdtKind::Union => AdtFlags::IS_UNION,
AdtKind::Struct => AdtFlags::IS_STRUCT,
};
if kind == AdtKind::Struct && variants[VariantIdx::new(0)].ctor_def_id.is_some() {
flags |= AdtFlags::HAS_CTOR;
}
let attrs = tcx.get_attrs(did);
if attr::contains_name(&attrs, sym::fundamental) {
flags |= AdtFlags::IS_FUNDAMENTAL;
}
if Some(did) == tcx.lang_items().phantom_data() {
flags |= AdtFlags::IS_PHANTOM_DATA;
}
if Some(did) == tcx.lang_items().owned_box() {
flags |= AdtFlags::IS_BOX;
}
if Some(did) == tcx.lang_items().arc() {
flags |= AdtFlags::IS_ARC;
}
if Some(did) == tcx.lang_items().rc() {
flags |= AdtFlags::IS_RC;
}
AdtDef {
did,
variants,
flags,
repr,
}
}
/// Returns `true` if this is a struct.
#[inline]
pub fn is_struct(&self) -> bool {
self.flags.contains(AdtFlags::IS_STRUCT)
}
/// Returns `true` if this is a union.
#[inline]
pub fn is_union(&self) -> bool {
self.flags.contains(AdtFlags::IS_UNION)
}
/// Returns `true` if this is a enum.
#[inline]
pub fn is_enum(&self) -> bool {
self.flags.contains(AdtFlags::IS_ENUM)
}
/// Returns `true` if the variant list of this ADT is `#[non_exhaustive]`.
#[inline]
pub fn is_variant_list_non_exhaustive(&self) -> bool {
self.flags.contains(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
}
/// Returns the kind of the ADT.
#[inline]
pub fn adt_kind(&self) -> AdtKind {
if self.is_enum() {
AdtKind::Enum
} else if self.is_union() {
AdtKind::Union
} else {
AdtKind::Struct
}
}
/// Returns a description of this abstract data type.
pub fn descr(&self) -> &'static str {
match self.adt_kind() {
AdtKind::Struct => "struct",
AdtKind::Union => "union",
AdtKind::Enum => "enum",
}
}
/// Returns a description of a variant of this abstract data type.
#[inline]
pub fn variant_descr(&self) -> &'static str {
match self.adt_kind() {
AdtKind::Struct => "struct",
AdtKind::Union => "union",
AdtKind::Enum => "variant",
}
}
/// If this function returns `true`, it implies that `is_struct` must return `true`.
#[inline]
pub fn has_ctor(&self) -> bool {
self.flags.contains(AdtFlags::HAS_CTOR)
}
/// Returns `true` if this type is `#[fundamental]` for the purposes
/// of coherence checking.
#[inline]
pub fn is_fundamental(&self) -> bool {
self.flags.contains(AdtFlags::IS_FUNDAMENTAL)
}
/// Returns `true` if this is `PhantomData<T>`.
#[inline]
pub fn is_phantom_data(&self) -> bool {
self.flags.contains(AdtFlags::IS_PHANTOM_DATA)
}
/// Returns `true` if this is `Arc<T>`.
pub fn is_arc(&self) -> bool {
self.flags.contains(AdtFlags::IS_ARC)
}
/// Returns `true` if this is `Rc<T>`.
pub fn is_rc(&self) -> bool {
self.flags.contains(AdtFlags::IS_RC)
}
/// Returns `true` if this is Box<T>.
#[inline]
pub fn is_box(&self) -> bool {
self.flags.contains(AdtFlags::IS_BOX)
}
/// Returns `true` if this type has a destructor.
pub fn has_dtor(&self, tcx: TyCtxt<'tcx>) -> bool {
self.destructor(tcx).is_some()
}
/// Asserts this is a struct or union and returns its unique variant.
pub fn non_enum_variant(&self) -> &VariantDef {
assert!(self.is_struct() || self.is_union());
&self.variants[VariantIdx::new(0)]
}
#[inline]
pub fn predicates(&self, tcx: TyCtxt<'tcx>) -> &'tcx GenericPredicates<'tcx> {
tcx.predicates_of(self.did)
}
/// Returns an iterator over all fields contained
/// by this ADT.
#[inline]
pub fn all_fields(&self) -> impl Iterator<Item=&FieldDef> + Clone {
self.variants.iter().flat_map(|v| v.fields.iter())
}
pub fn is_payloadfree(&self) -> bool {
!self.variants.is_empty() &&
self.variants.iter().all(|v| v.fields.is_empty())
}
/// Return a `VariantDef` given a variant id.
pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
self.variants.iter().find(|v| v.def_id == vid)
.expect("variant_with_id: unknown variant")
}
/// Return a `VariantDef` given a constructor id.
pub fn variant_with_ctor_id(&self, cid: DefId) -> &VariantDef {
self.variants.iter().find(|v| v.ctor_def_id == Some(cid))
.expect("variant_with_ctor_id: unknown variant")
}
/// Return the index of `VariantDef` given a variant id.
pub fn variant_index_with_id(&self, vid: DefId) -> VariantIdx {
self.variants.iter_enumerated().find(|(_, v)| v.def_id == vid)
.expect("variant_index_with_id: unknown variant").0
}
/// Return the index of `VariantDef` given a constructor id.
pub fn variant_index_with_ctor_id(&self, cid: DefId) -> VariantIdx {
self.variants.iter_enumerated().find(|(_, v)| v.ctor_def_id == Some(cid))
.expect("variant_index_with_ctor_id: unknown variant").0
}
pub fn variant_of_res(&self, res: Res) -> &VariantDef {
match res {
Res::Def(DefKind::Variant, vid) => self.variant_with_id(vid),
Res::Def(DefKind::Ctor(..), cid) => self.variant_with_ctor_id(cid),
Res::Def(DefKind::Struct, _) | Res::Def(DefKind::Union, _) |
Res::Def(DefKind::TyAlias, _) | Res::Def(DefKind::AssocTy, _) | Res::SelfTy(..) |
Res::SelfCtor(..) => self.non_enum_variant(),
_ => bug!("unexpected res {:?} in variant_of_res", res)
}
}
#[inline]
pub fn eval_explicit_discr(&self, tcx: TyCtxt<'tcx>, expr_did: DefId) -> Option<Discr<'tcx>> {
let param_env = ParamEnv::empty();
let repr_type = self.repr.discr_type();
let substs = InternalSubsts::identity_for_item(tcx.global_tcx(), expr_did);
let instance = ty::Instance::new(expr_did, substs);
let cid = GlobalId {
instance,
promoted: None
};
match tcx.const_eval(param_env.and(cid)) {
Ok(val) => {
// FIXME: Find the right type and use it instead of `val.ty` here
if let Some(b) = val.assert_bits(tcx.global_tcx(), param_env.and(val.ty)) {
trace!("discriminants: {} ({:?})", b, repr_type);
Some(Discr {
val: b,
ty: val.ty,
})
} else {
info!("invalid enum discriminant: {:#?}", val);
crate::mir::interpret::struct_error(
tcx.at(tcx.def_span(expr_did)),
"constant evaluation of enum discriminant resulted in non-integer",
).emit();
None
}
}
Err(ErrorHandled::Reported) => {
if !expr_did.is_local() {
span_bug!(tcx.def_span(expr_did),
"variant discriminant evaluation succeeded \
in its crate but failed locally");
}
None
}
Err(ErrorHandled::TooGeneric) => span_bug!(
tcx.def_span(expr_did),
"enum discriminant depends on generic arguments",
),
}
}
#[inline]
pub fn discriminants(
&'tcx self,
tcx: TyCtxt<'tcx>,
) -> impl Iterator<Item = (VariantIdx, Discr<'tcx>)> + Captures<'tcx> {
let repr_type = self.repr.discr_type();
let initial = repr_type.initial_discriminant(tcx.global_tcx());
let mut prev_discr = None::<Discr<'tcx>>;
self.variants.iter_enumerated().map(move |(i, v)| {
let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
if let VariantDiscr::Explicit(expr_did) = v.discr {
if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
discr = new_discr;
}
}
prev_discr = Some(discr);
(i, discr)
})
}
#[inline]
pub fn variant_range(&self) -> Range<VariantIdx> {
(VariantIdx::new(0)..VariantIdx::new(self.variants.len()))
}
/// Computes the discriminant value used by a specific variant.
/// Unlike `discriminants`, this is (amortized) constant-time,
/// only doing at most one query for evaluating an explicit
/// discriminant (the last one before the requested variant),
/// assuming there are no constant-evaluation errors there.
#[inline]
pub fn discriminant_for_variant(
&self,
tcx: TyCtxt<'tcx>,
variant_index: VariantIdx,
) -> Discr<'tcx> {
let (val, offset) = self.discriminant_def_for_variant(variant_index);
let explicit_value = val
.and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
.unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx.global_tcx()));
explicit_value.checked_add(tcx, offset as u128).0
}
/// Yields a `DefId` for the discriminant and an offset to add to it
/// Alternatively, if there is no explicit discriminant, returns the
/// inferred discriminant directly.
pub fn discriminant_def_for_variant(
&self,
variant_index: VariantIdx,
) -> (Option<DefId>, u32) {
let mut explicit_index = variant_index.as_u32();
let expr_did;
loop {
match self.variants[VariantIdx::from_u32(explicit_index)].discr {
ty::VariantDiscr::Relative(0) => {
expr_did = None;
break;
},
ty::VariantDiscr::Relative(distance) => {
explicit_index -= distance;
}
ty::VariantDiscr::Explicit(did) => {
expr_did = Some(did);
break;
}
}
}
(expr_did, variant_index.as_u32() - explicit_index)
}
pub fn destructor(&self, tcx: TyCtxt<'tcx>) -> Option<Destructor> {
tcx.adt_destructor(self.did)
}
/// Returns a list of types such that `Self: Sized` if and only
/// if that type is `Sized`, or `TyErr` if this type is recursive.
///
/// Oddly enough, checking that the sized-constraint is `Sized` is
/// actually more expressive than checking all members:
/// the `Sized` trait is inductive, so an associated type that references
/// `Self` would prevent its containing ADT from being `Sized`.
///
/// Due to normalization being eager, this applies even if
/// the associated type is behind a pointer (e.g., issue #31299).
pub fn sized_constraint(&self, tcx: TyCtxt<'tcx>) -> &'tcx [Ty<'tcx>] {
tcx.adt_sized_constraint(self.did).0
}
fn sized_constraint_for_ty(&self, tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Vec<Ty<'tcx>> {
let result = match ty.sty {
Bool | Char | Int(..) | Uint(..) | Float(..) |
RawPtr(..) | Ref(..) | FnDef(..) | FnPtr(_) |
Array(..) | Closure(..) | Generator(..) | Never => {
vec![]
}
Str |
Dynamic(..) |
Slice(_) |
Foreign(..) |
Error |
GeneratorWitness(..) => {
// these are never sized - return the target type
vec![ty]
}
Tuple(ref tys) => {
match tys.last() {
None => vec![],
Some(ty) => self.sized_constraint_for_ty(tcx, ty.expect_ty()),
}
}
Adt(adt, substs) => {
// recursive case
let adt_tys = adt.sized_constraint(tcx);
debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
ty, adt_tys);
adt_tys.iter()
.map(|ty| ty.subst(tcx, substs))
.flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
.collect()
}
Projection(..) | Opaque(..) => {
// must calculate explicitly.
// FIXME: consider special-casing always-Sized projections
vec![ty]
}
UnnormalizedProjection(..) => bug!("only used with chalk-engine"),
Param(..) => {
// perf hack: if there is a `T: Sized` bound, then
// we know that `T` is Sized and do not need to check
// it on the impl.
let sized_trait = match tcx.lang_items().sized_trait() {
Some(x) => x,
_ => return vec![ty]
};
let sized_predicate = Binder::dummy(TraitRef {
def_id: sized_trait,
substs: tcx.mk_substs_trait(ty, &[])
}).to_predicate();
let predicates = &tcx.predicates_of(self.did).predicates;
if predicates.iter().any(|(p, _)| *p == sized_predicate) {
vec![]
} else {
vec![ty]
}
}
Placeholder(..) |
Bound(..) |
Infer(..) => {
bug!("unexpected type `{:?}` in sized_constraint_for_ty",
ty)
}
};
debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
result
}
}
impl<'tcx> FieldDef {
pub fn ty(&self, tcx: TyCtxt<'tcx>, subst: SubstsRef<'tcx>) -> Ty<'tcx> {
tcx.type_of(self.did).subst(tcx, subst)
}
}
/// Represents the various closure traits in the language. This
/// will determine the type of the environment (`self`, in the
/// desugaring) argument that the closure expects.
///
/// You can get the environment type of a closure using
/// `tcx.closure_env_ty()`.
#[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug,
RustcEncodable, RustcDecodable, HashStable)]
pub enum ClosureKind {
// Warning: Ordering is significant here! The ordering is chosen
// because the trait Fn is a subtrait of FnMut and so in turn, and
// hence we order it so that Fn < FnMut < FnOnce.
Fn,
FnMut,
FnOnce,
}
impl<'tcx> ClosureKind {
// This is the initial value used when doing upvar inference.
pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
pub fn trait_did(&self, tcx: TyCtxt<'tcx>) -> DefId {
match *self {
ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
ClosureKind::FnMut => {
tcx.require_lang_item(FnMutTraitLangItem)
}
ClosureKind::FnOnce => {
tcx.require_lang_item(FnOnceTraitLangItem)
}
}
}
/// Returns `true` if this a type that impls this closure kind
/// must also implement `other`.
pub fn extends(self, other: ty::ClosureKind) -> bool {
match (self, other) {
(ClosureKind::Fn, ClosureKind::Fn) => true,
(ClosureKind::Fn, ClosureKind::FnMut) => true,
(ClosureKind::Fn, ClosureKind::FnOnce) => true,
(ClosureKind::FnMut, ClosureKind::FnMut) => true,
(ClosureKind::FnMut, ClosureKind::FnOnce) => true,
(ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
_ => false,
}
}
/// Returns the representative scalar type for this closure kind.
/// See `TyS::to_opt_closure_kind` for more details.
pub fn to_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
match self {
ty::ClosureKind::Fn => tcx.types.i8,
ty::ClosureKind::FnMut => tcx.types.i16,
ty::ClosureKind::FnOnce => tcx.types.i32,
}
}
}
impl<'tcx> TyS<'tcx> {
/// Iterator that walks `self` and any types reachable from
/// `self`, in depth-first order. Note that just walks the types
/// that appear in `self`, it does not descend into the fields of
/// structs or variants. For example:
///
/// ```notrust
/// isize => { isize }
/// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
/// [isize] => { [isize], isize }
/// ```
pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
TypeWalker::new(self)
}
/// Iterator that walks the immediate children of `self`. Hence
/// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
/// (but not `i32`, like `walk`).
pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
walk::walk_shallow(self)
}
/// Walks `ty` and any types appearing within `ty`, invoking the
/// callback `f` on each type. If the callback returns `false`, then the
/// children of the current type are ignored.
///
/// Note: prefer `ty.walk()` where possible.
pub fn maybe_walk<F>(&'tcx self, mut f: F)
where F: FnMut(Ty<'tcx>) -> bool
{
let mut walker = self.walk();
while let Some(ty) = walker.next() {
if !f(ty) {
walker.skip_current_subtree();
}
}
}
}
impl BorrowKind {
pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
match m {
hir::MutMutable => MutBorrow,
hir::MutImmutable => ImmBorrow,
}
}
/// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
/// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
/// mutability that is stronger than necessary so that it at least *would permit* the borrow in
/// question.
pub fn to_mutbl_lossy(self) -> hir::Mutability {
match self {
MutBorrow => hir::MutMutable,
ImmBorrow => hir::MutImmutable,
// We have no type corresponding to a unique imm borrow, so
// use `&mut`. It gives all the capabilities of an `&uniq`
// and hence is a safe "over approximation".
UniqueImmBorrow => hir::MutMutable,
}
}
pub fn to_user_str(&self) -> &'static str {
match *self {
MutBorrow => "mutable",
ImmBorrow => "immutable",
UniqueImmBorrow => "uniquely immutable",
}
}
}
#[derive(Debug, Clone)]
pub enum Attributes<'tcx> {
Owned(Lrc<[ast::Attribute]>),
Borrowed(&'tcx [ast::Attribute]),
}
impl<'tcx> ::std::ops::Deref for Attributes<'tcx> {
type Target = [ast::Attribute];
fn deref(&self) -> &[ast::Attribute] {
match self {
&Attributes::Owned(ref data) => &data,
&Attributes::Borrowed(data) => data
}
}
}
#[derive(Debug, PartialEq, Eq)]
pub enum ImplOverlapKind {
/// These impls are always allowed to overlap.
Permitted,
/// These impls are allowed to overlap, but that raises
/// an issue #33140 future-compatibility warning.
///
/// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's
/// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different.
///
/// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied
/// that difference, making what reduces to the following set of impls:
///
/// ```
/// trait Trait {}
/// impl Trait for dyn Send + Sync {}
/// impl Trait for dyn Sync + Send {}
/// ```
///
/// Obviously, once we made these types be identical, that code causes a coherence
/// error and a fairly big headache for us. However, luckily for us, the trait
/// `Trait` used in this case is basically a marker trait, and therefore having
/// overlapping impls for it is sound.
///
/// To handle this, we basically regard the trait as a marker trait, with an additional
/// future-compatibility warning. To avoid accidentally "stabilizing" this feature,
/// it has the following restrictions:
///
/// 1. The trait must indeed be a marker-like trait (i.e., no items), and must be
/// positive impls.
/// 2. The trait-ref of both impls must be equal.
/// 3. The trait-ref of both impls must be a trait object type consisting only of
/// marker traits.
/// 4. Neither of the impls can have any where-clauses.
///
/// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed.
Issue33140
}
impl<'tcx> TyCtxt<'tcx> {
pub fn body_tables(self, body: hir::BodyId) -> &'tcx TypeckTables<'tcx> {
self.typeck_tables_of(self.hir().body_owner_def_id(body))
}
/// Returns an iterator of the `DefId`s for all body-owners in this
/// crate. If you would prefer to iterate over the bodies
/// themselves, you can do `self.hir().krate().body_ids.iter()`.
pub fn body_owners(self) -> impl Iterator<Item = DefId> + Captures<'tcx> + 'tcx {
self.hir().krate()
.body_ids
.iter()
.map(move |&body_id| self.hir().body_owner_def_id(body_id))
}
pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
par_iter(&self.hir().krate().body_ids).for_each(|&body_id| {
f(self.hir().body_owner_def_id(body_id))
});
}
pub fn provided_trait_methods(self, id: DefId) -> Vec<AssocItem> {
self.associated_items(id)
.filter(|item| item.kind == AssocKind::Method && item.defaultness.has_value())
.collect()
}
pub fn trait_relevant_for_never(self, did: DefId) -> bool {
self.associated_items(did).any(|item| {
item.relevant_for_never()
})
}
pub fn opt_associated_item(self, def_id: DefId) -> Option<AssocItem> {
let is_associated_item = if let Some(hir_id) = self.hir().as_local_hir_id(def_id) {
match self.hir().get(hir_id) {
Node::TraitItem(_) | Node::ImplItem(_) => true,
_ => false,
}
} else {
match self.def_kind(def_id).expect("no def for def-id") {
DefKind::AssocConst
| DefKind::Method
| DefKind::AssocTy => true,
_ => false,
}
};
if is_associated_item {
Some(self.associated_item(def_id))
} else {
None
}
}
fn associated_item_from_trait_item_ref(self,
parent_def_id: DefId,
parent_vis: &hir::Visibility,
trait_item_ref: &hir::TraitItemRef)
-> AssocItem {
let def_id = self.hir().local_def_id(trait_item_ref.id.hir_id);
let (kind, has_self) = match trait_item_ref.kind {
hir::AssocItemKind::Const => (ty::AssocKind::Const, false),
hir::AssocItemKind::Method { has_self } => {
(ty::AssocKind::Method, has_self)
}
hir::AssocItemKind::Type => (ty::AssocKind::Type, false),
hir::AssocItemKind::Existential => bug!("only impls can have existentials"),
};
AssocItem {
ident: trait_item_ref.ident,
kind,
// Visibility of trait items is inherited from their traits.
vis: Visibility::from_hir(parent_vis, trait_item_ref.id.hir_id, self),
defaultness: trait_item_ref.defaultness,
def_id,
container: TraitContainer(parent_def_id),
method_has_self_argument: has_self
}
}
fn associated_item_from_impl_item_ref(self,
parent_def_id: DefId,
impl_item_ref: &hir::ImplItemRef)
-> AssocItem {
let def_id = self.hir().local_def_id(impl_item_ref.id.hir_id);
let (kind, has_self) = match impl_item_ref.kind {
hir::AssocItemKind::Const => (ty::AssocKind::Const, false),
hir::AssocItemKind::Method { has_self } => {
(ty::AssocKind::Method, has_self)
}
hir::AssocItemKind::Type => (ty::AssocKind::Type, false),
hir::AssocItemKind::Existential => (ty::AssocKind::Existential, false),
};
AssocItem {
ident: impl_item_ref.ident,
kind,
// Visibility of trait impl items doesn't matter.
vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.hir_id, self),
defaultness: impl_item_ref.defaultness,
def_id,
container: ImplContainer(parent_def_id),
method_has_self_argument: has_self
}
}
pub fn field_index(self, hir_id: hir::HirId, tables: &TypeckTables<'_>) -> usize {
tables.field_indices().get(hir_id).cloned().expect("no index for a field")
}
pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
variant.fields.iter().position(|field| {
self.hygienic_eq(ident, field.ident, variant.def_id)
})
}
pub fn associated_items(self, def_id: DefId) -> AssocItemsIterator<'tcx> {
// Ideally, we would use `-> impl Iterator` here, but it falls
// afoul of the conservative "capture [restrictions]" we put
// in place, so we use a hand-written iterator.
//
// [restrictions]: https://github.com/rust-lang/rust/issues/34511#issuecomment-373423999
AssocItemsIterator {
tcx: self,
def_ids: self.associated_item_def_ids(def_id),
next_index: 0,
}
}
/// Returns `true` if the impls are the same polarity and the trait either
/// has no items or is annotated #[marker] and prevents item overrides.
pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId)
-> Option<ImplOverlapKind>
{
let is_legit = if self.features().overlapping_marker_traits {
let trait1_is_empty = self.impl_trait_ref(def_id1)
.map_or(false, |trait_ref| {
self.associated_item_def_ids(trait_ref.def_id).is_empty()
});
let trait2_is_empty = self.impl_trait_ref(def_id2)
.map_or(false, |trait_ref| {
self.associated_item_def_ids(trait_ref.def_id).is_empty()
});
self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
&& trait1_is_empty
&& trait2_is_empty
} else {
let is_marker_impl = |def_id: DefId| -> bool {
let trait_ref = self.impl_trait_ref(def_id);
trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
};
self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
&& is_marker_impl(def_id1)
&& is_marker_impl(def_id2)
};
if is_legit {
debug!("impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted)",
def_id1, def_id2);
Some(ImplOverlapKind::Permitted)
} else {
if let Some(self_ty1) = self.issue33140_self_ty(def_id1) {
if let Some(self_ty2) = self.issue33140_self_ty(def_id2) {
if self_ty1 == self_ty2 {
debug!("impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK",
def_id1, def_id2);
return Some(ImplOverlapKind::Issue33140);
} else {
debug!("impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}",
def_id1, def_id2, self_ty1, self_ty2);
}
}
}
debug!("impls_are_allowed_to_overlap({:?}, {:?}) = None",
def_id1, def_id2);
None
}
}
/// Returns `ty::VariantDef` if `res` refers to a struct,
/// or variant or their constructors, panics otherwise.
pub fn expect_variant_res(self, res: Res) -> &'tcx VariantDef {
match res {
Res::Def(DefKind::Variant, did) => {
let enum_did = self.parent(did).unwrap();
self.adt_def(enum_did).variant_with_id(did)
}
Res::Def(DefKind::Struct, did) | Res::Def(DefKind::Union, did) => {
self.adt_def(did).non_enum_variant()
}
Res::Def(DefKind::Ctor(CtorOf::Variant, ..), variant_ctor_did) => {
let variant_did = self.parent(variant_ctor_did).unwrap();
let enum_did = self.parent(variant_did).unwrap();
self.adt_def(enum_did).variant_with_ctor_id(variant_ctor_did)
}
Res::Def(DefKind::Ctor(CtorOf::Struct, ..), ctor_did) => {
let struct_did = self.parent(ctor_did).expect("struct ctor has no parent");
self.adt_def(struct_did).non_enum_variant()
}
_ => bug!("expect_variant_res used with unexpected res {:?}", res)
}
}
pub fn item_name(self, id: DefId) -> Symbol {
if id.index == CRATE_DEF_INDEX {
self.original_crate_name(id.krate)
} else {
let def_key = self.def_key(id);
match def_key.disambiguated_data.data {
// The name of a constructor is that of its parent.
hir_map::DefPathData::Ctor =>
self.item_name(DefId {
krate: id.krate,
index: def_key.parent.unwrap()
}),
_ => def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
bug!("item_name: no name for {:?}", self.def_path(id));
}).as_symbol(),
}
}
}
/// Returns the possibly-auto-generated MIR of a `(DefId, Subst)` pair.
pub fn instance_mir(self, instance: ty::InstanceDef<'tcx>) -> &'tcx Body<'tcx> {
match instance {
ty::InstanceDef::Item(did) => {
self.optimized_mir(did)
}
ty::InstanceDef::VtableShim(..) |
ty::InstanceDef::Intrinsic(..) |
ty::InstanceDef::FnPtrShim(..) |
ty::InstanceDef::Virtual(..) |
ty::InstanceDef::ClosureOnceShim { .. } |
ty::InstanceDef::DropGlue(..) |
ty::InstanceDef::CloneShim(..) => {
self.mir_shims(instance)
}
}
}
/// Gets the attributes of a definition.
pub fn get_attrs(self, did: DefId) -> Attributes<'tcx> {
if let Some(id) = self.hir().as_local_hir_id(did) {
Attributes::Borrowed(self.hir().attrs(id))
} else {
Attributes::Owned(self.item_attrs(did))
}
}
/// Determines whether an item is annotated with an attribute.
pub fn has_attr(self, did: DefId, attr: Symbol) -> bool {
attr::contains_name(&self.get_attrs(did), attr)
}
/// Returns `true` if this is an `auto trait`.
pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
self.trait_def(trait_def_id).has_auto_impl
}
pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
}
/// Given the `DefId` of an impl, returns the `DefId` of the trait it implements.
/// If it implements no trait, returns `None`.
pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
self.impl_trait_ref(def_id).map(|tr| tr.def_id)
}
/// If the given defid describes a method belonging to an impl, returns the
/// `DefId` of the impl that the method belongs to; otherwise, returns `None`.
pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
let item = if def_id.krate != LOCAL_CRATE {
if let Some(DefKind::Method) = self.def_kind(def_id) {
Some(self.associated_item(def_id))
} else {
None
}
} else {
self.opt_associated_item(def_id)
};
item.and_then(|trait_item|
match trait_item.container {
TraitContainer(_) => None,
ImplContainer(def_id) => Some(def_id),
}
)
}
/// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
/// with the name of the crate containing the impl.
pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
if impl_did.is_local() {
let hir_id = self.hir().as_local_hir_id(impl_did).unwrap();
Ok(self.hir().span(hir_id))
} else {
Err(self.crate_name(impl_did.krate))
}
}
/// Hygienically compares a use-site name (`use_name`) for a field or an associated item with
/// its supposed definition name (`def_name`). The method also needs `DefId` of the supposed
/// definition's parent/scope to perform comparison.
pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
// We could use `Ident::eq` here, but we deliberately don't. The name
// comparison fails frequently, and we want to avoid the expensive
// `modern()` calls required for the span comparison whenever possible.
use_name.name == def_name.name &&
use_name.span.ctxt().hygienic_eq(def_name.span.ctxt(),
self.expansion_that_defined(def_parent_def_id))
}
fn expansion_that_defined(self, scope: DefId) -> ExpnId {
match scope.krate {
LOCAL_CRATE => self.hir().definitions().expansion_that_defined(scope.index),
_ => ExpnId::root(),
}
}
pub fn adjust_ident(self, mut ident: Ident, scope: DefId) -> Ident {
ident.span.modernize_and_adjust(self.expansion_that_defined(scope));
ident
}
pub fn adjust_ident_and_get_scope(self, mut ident: Ident, scope: DefId, block: hir::HirId)
-> (Ident, DefId) {
let scope = match ident.span.modernize_and_adjust(self.expansion_that_defined(scope)) {
Some(actual_expansion) =>
self.hir().definitions().parent_module_of_macro_def(actual_expansion),
None => self.hir().get_module_parent(block),
};
(ident, scope)
}
}
pub struct AssocItemsIterator<'tcx> {
tcx: TyCtxt<'tcx>,
def_ids: &'tcx [DefId],
next_index: usize,
}
impl Iterator for AssocItemsIterator<'_> {
type Item = AssocItem;
fn next(&mut self) -> Option<AssocItem> {
let def_id = self.def_ids.get(self.next_index)?;
self.next_index += 1;
Some(self.tcx.associated_item(*def_id))
}
}
fn associated_item(tcx: TyCtxt<'_>, def_id: DefId) -> AssocItem {
let id = tcx.hir().as_local_hir_id(def_id).unwrap();
let parent_id = tcx.hir().get_parent_item(id);
let parent_def_id = tcx.hir().local_def_id(parent_id);
let parent_item = tcx.hir().expect_item(parent_id);
match parent_item.node {
hir::ItemKind::Impl(.., ref impl_item_refs) => {
if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.hir_id == id) {
let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
impl_item_ref);
debug_assert_eq!(assoc_item.def_id, def_id);
return assoc_item;
}
}
hir::ItemKind::Trait(.., ref trait_item_refs) => {
if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.hir_id == id) {
let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
&parent_item.vis,
trait_item_ref);
debug_assert_eq!(assoc_item.def_id, def_id);
return assoc_item;
}
}
_ => { }
}
span_bug!(parent_item.span,
"unexpected parent of trait or impl item or item not found: {:?}",
parent_item.node)
}
#[derive(Clone, HashStable)]
pub struct AdtSizedConstraint<'tcx>(pub &'tcx [Ty<'tcx>]);
/// Calculates the `Sized` constraint.
///
/// In fact, there are only a few options for the types in the constraint:
/// - an obviously-unsized type
/// - a type parameter or projection whose Sizedness can't be known
/// - a tuple of type parameters or projections, if there are multiple
/// such.
/// - a Error, if a type contained itself. The representability
/// check should catch this case.
fn adt_sized_constraint(tcx: TyCtxt<'_>, def_id: DefId) -> AdtSizedConstraint<'_> {
let def = tcx.adt_def(def_id);
let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| {
v.fields.last()
}).flat_map(|f| {
def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
}));
debug!("adt_sized_constraint: {:?} => {:?}", def, result);
AdtSizedConstraint(result)
}
fn associated_item_def_ids(tcx: TyCtxt<'_>, def_id: DefId) -> &[DefId] {
let id = tcx.hir().as_local_hir_id(def_id).unwrap();
let item = tcx.hir().expect_item(id);
match item.node {
hir::ItemKind::Trait(.., ref trait_item_refs) => {
tcx.arena.alloc_from_iter(
trait_item_refs.iter()
.map(|trait_item_ref| trait_item_ref.id)
.map(|id| tcx.hir().local_def_id(id.hir_id))
)
}
hir::ItemKind::Impl(.., ref impl_item_refs) => {
tcx.arena.alloc_from_iter(
impl_item_refs.iter()
.map(|impl_item_ref| impl_item_ref.id)
.map(|id| tcx.hir().local_def_id(id.hir_id))
)
}
hir::ItemKind::TraitAlias(..) => &[],
_ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
}
}
fn def_span(tcx: TyCtxt<'_>, def_id: DefId) -> Span {
tcx.hir().span_if_local(def_id).unwrap()
}
/// If the given `DefId` describes an item belonging to a trait,
/// returns the `DefId` of the trait that the trait item belongs to;
/// otherwise, returns `None`.
fn trait_of_item(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
tcx.opt_associated_item(def_id)
.and_then(|associated_item| {
match associated_item.container {
TraitContainer(def_id) => Some(def_id),
ImplContainer(_) => None
}
})
}
/// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
pub fn is_impl_trait_defn(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
if let Node::Item(item) = tcx.hir().get(hir_id) {
if let hir::ItemKind::Existential(ref exist_ty) = item.node {
return exist_ty.impl_trait_fn;
}
}
}
None
}
/// See `ParamEnv` struct definition for details.
fn param_env(tcx: TyCtxt<'_>, def_id: DefId) -> ParamEnv<'_> {
// The param_env of an impl Trait type is its defining function's param_env
if let Some(parent) = is_impl_trait_defn(tcx, def_id) {
return param_env(tcx, parent);
}
// Compute the bounds on Self and the type parameters.
let InstantiatedPredicates { predicates } =
tcx.predicates_of(def_id).instantiate_identity(tcx);
// Finally, we have to normalize the bounds in the environment, in
// case they contain any associated type projections. This process
// can yield errors if the put in illegal associated types, like
// `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
// report these errors right here; this doesn't actually feel
// right to me, because constructing the environment feels like a
// kind of a "idempotent" action, but I'm not sure where would be
// a better place. In practice, we construct environments for
// every fn once during type checking, and we'll abort if there
// are any errors at that point, so after type checking you can be
// sure that this will succeed without errors anyway.
let unnormalized_env = ty::ParamEnv::new(
tcx.intern_predicates(&predicates),
traits::Reveal::UserFacing,
if tcx.sess.opts.debugging_opts.chalk { Some(def_id) } else { None }
);
let body_id = tcx.hir().as_local_hir_id(def_id).map_or(hir::DUMMY_HIR_ID, |id| {
tcx.hir().maybe_body_owned_by(id).map_or(id, |body| body.hir_id)
});
let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
}
fn crate_disambiguator(tcx: TyCtxt<'_>, crate_num: CrateNum) -> CrateDisambiguator {
assert_eq!(crate_num, LOCAL_CRATE);
tcx.sess.local_crate_disambiguator()
}
fn original_crate_name(tcx: TyCtxt<'_>, crate_num: CrateNum) -> Symbol {
assert_eq!(crate_num, LOCAL_CRATE);
tcx.crate_name.clone()
}
fn crate_hash(tcx: TyCtxt<'_>, crate_num: CrateNum) -> Svh {
assert_eq!(crate_num, LOCAL_CRATE);
tcx.hir().crate_hash
}
fn instance_def_size_estimate<'tcx>(tcx: TyCtxt<'tcx>, instance_def: InstanceDef<'tcx>) -> usize {
match instance_def {
InstanceDef::Item(..) |
InstanceDef::DropGlue(..) => {
let mir = tcx.instance_mir(instance_def);
mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
},
// Estimate the size of other compiler-generated shims to be 1.
_ => 1
}
}
/// If `def_id` is an issue 33140 hack impl, returns its self type; otherwise, returns `None`.
///
/// See [`ImplOverlapKind::Issue33140`] for more details.
fn issue33140_self_ty(tcx: TyCtxt<'_>, def_id: DefId) -> Option<Ty<'_>> {
debug!("issue33140_self_ty({:?})", def_id);
let trait_ref = tcx.impl_trait_ref(def_id).unwrap_or_else(|| {
bug!("issue33140_self_ty called on inherent impl {:?}", def_id)
});
debug!("issue33140_self_ty({:?}), trait-ref={:?}", def_id, trait_ref);
let is_marker_like =
tcx.impl_polarity(def_id) == hir::ImplPolarity::Positive &&
tcx.associated_item_def_ids(trait_ref.def_id).is_empty();
// Check whether these impls would be ok for a marker trait.
if !is_marker_like {
debug!("issue33140_self_ty - not marker-like!");
return None;
}
// impl must be `impl Trait for dyn Marker1 + Marker2 + ...`
if trait_ref.substs.len() != 1 {
debug!("issue33140_self_ty - impl has substs!");
return None;
}
let predicates = tcx.predicates_of(def_id);
if predicates.parent.is_some() || !predicates.predicates.is_empty() {
debug!("issue33140_self_ty - impl has predicates {:?}!", predicates);
return None;
}
let self_ty = trait_ref.self_ty();
let self_ty_matches = match self_ty.sty {
ty::Dynamic(ref data, ty::ReStatic) => data.principal().is_none(),
_ => false
};
if self_ty_matches {
debug!("issue33140_self_ty - MATCHES!");
Some(self_ty)
} else {
debug!("issue33140_self_ty - non-matching self type");
None
}
}
pub fn provide(providers: &mut ty::query::Providers<'_>) {
context::provide(providers);
erase_regions::provide(providers);
layout::provide(providers);
util::provide(providers);
constness::provide(providers);
*providers = ty::query::Providers {
associated_item,
associated_item_def_ids,
adt_sized_constraint,
def_span,
param_env,
trait_of_item,
crate_disambiguator,
original_crate_name,
crate_hash,
trait_impls_of: trait_def::trait_impls_of_provider,
instance_def_size_estimate,
issue33140_self_ty,
..*providers
};
}
/// A map for the local crate mapping each type to a vector of its
/// inherent impls. This is not meant to be used outside of coherence;
/// rather, you should request the vector for a specific type via
/// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
/// (constructing this map requires touching the entire crate).
#[derive(Clone, Debug, Default, HashStable)]
pub struct CrateInherentImpls {
pub inherent_impls: DefIdMap<Vec<DefId>>,
}
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
pub struct SymbolName {
// FIXME: we don't rely on interning or equality here - better have
// this be a `&'tcx str`.
pub name: InternedString
}
impl_stable_hash_for!(struct self::SymbolName {
name
});
impl SymbolName {
pub fn new(name: &str) -> SymbolName {
SymbolName {
name: InternedString::intern(name)
}
}
pub fn as_str(&self) -> LocalInternedString {
self.name.as_str()
}
}
impl fmt::Display for SymbolName {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Display::fmt(&self.name, fmt)
}
}
impl fmt::Debug for SymbolName {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Display::fmt(&self.name, fmt)
}
}
You can’t perform that action at this time.