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Auto merge of #82964 - Nicholas-Baron:shorten_middle_ty, r=jackh726

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Shorten `rustc_middle::ty::mod`

Related to #60302.

This PR moves all `Adt*`, `Assoc*`, `Generic*`, and `UpVar*` types to separate files.
This, alongside some `use` reordering, puts `mod.rs` at ~2,200 lines, thus removing the `// ignore-tidy-filelength`.

The particular groups were chosen as they had 4 or more "substantive" members.
This commit is contained in:
bors 2021-03-11 04:09:44 +00:00
commit b3ac52646f
5 changed files with 1283 additions and 1244 deletions
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482
compiler/rustc_middle/src/ty/adt.rs Normal file
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use crate::ich::StableHashingContext;
use crate::mir::interpret::ErrorHandled;
use crate::ty;
use crate::ty::util::{Discr, IntTypeExt};
use rustc_data_structures::captures::Captures;
use rustc_data_structures::fingerprint::Fingerprint;
use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
use rustc_errors::ErrorReported;
use rustc_hir::def::{DefKind, Res};
use rustc_hir::def_id::DefId;
use rustc_index::vec::{Idx, IndexVec};
use rustc_serialize::{self, Encodable, Encoder};
use rustc_session::DataTypeKind;
use rustc_span::symbol::sym;
use rustc_target::abi::VariantIdx;
use std::cell::RefCell;
use std::cmp::Ordering;
use std::hash::{Hash, Hasher};
use std::ops::Range;
use std::{ptr, str};
use super::{
Destructor, FieldDef, GenericPredicates, ReprOptions, Ty, TyCtxt, VariantDef, VariantDiscr,
};
#[derive(Clone, HashStable, Debug)]
pub struct AdtSizedConstraint<'tcx>(pub &'tcx [Ty<'tcx>]);
bitflags! {
#[derive(HashStable)]
pub struct AdtFlags: u32 {
const NO_ADT_FLAGS = 0;
/// Indicates whether the ADT is an enum.
const IS_ENUM = 1 << 0;
/// Indicates whether the ADT is a union.
const IS_UNION = 1 << 1;
/// Indicates whether the ADT is a struct.
const IS_STRUCT = 1 << 2;
/// Indicates whether the ADT is a struct and has a constructor.
const HAS_CTOR = 1 << 3;
/// Indicates whether the type is `PhantomData`.
const IS_PHANTOM_DATA = 1 << 4;
/// Indicates whether the type has a `#[fundamental]` attribute.
const IS_FUNDAMENTAL = 1 << 5;
/// Indicates whether the type is `Box`.
const IS_BOX = 1 << 6;
/// Indicates whether the type is `ManuallyDrop`.
const IS_MANUALLY_DROP = 1 << 7;
/// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
/// (i.e., this flag is never set unless this ADT is an enum).
const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 8;
}
}
/// The definition of a user-defined type, e.g., a `struct`, `enum`, or `union`.
///
/// These are all interned (by `alloc_adt_def`) into the global arena.
///
/// The initialism *ADT* stands for an [*algebraic data type (ADT)*][adt].
/// This is slightly wrong because `union`s are not ADTs.
/// Moreover, Rust only allows recursive data types through indirection.
///
/// [adt]: https://en.wikipedia.org/wiki/Algebraic_data_type
pub struct AdtDef {
/// The `DefId` of the struct, enum or union item.
pub did: DefId,
/// Variants of the ADT. If this is a struct or union, then there will be a single variant.
pub variants: IndexVec<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`s are always interned, and this is part of `TyS` equality.
#[inline]
fn eq(&self, other: &Self) -> bool {
ptr::eq(self, other)
}
}
impl Eq for AdtDef {}
impl Hash for AdtDef {
#[inline]
fn hash<H: Hasher>(&self, s: &mut H) {
(self as *const AdtDef).hash(s)
}
}
impl<S: Encoder> Encodable<S> for AdtDef {
fn encode(&self, s: &mut S) -> Result<(), S::Error> {
self.did.encode(s)
}
}
impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
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,
}
}
}
impl<'tcx> AdtDef {
/// Creates a new `AdtDef`.
pub(super) 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 tcx.sess.contains_name(&attrs, sym::fundamental) {
flags |= AdtFlags::IS_FUNDAMENTAL;
}
if Some(did) == tcx.lang_items().phantom_data() {
flags |= AdtFlags::IS_PHANTOM_DATA;
}
if Some(did) == tcx.lang_items().owned_box() {
flags |= AdtFlags::IS_BOX;
}
if Some(did) == tcx.lang_items().manually_drop() {
flags |= AdtFlags::IS_MANUALLY_DROP;
}
AdtDef { did, variants, flags, repr }
}
/// Returns `true` if this is a struct.
#[inline]
pub fn is_struct(&self) -> bool {
self.flags.contains(AdtFlags::IS_STRUCT)
}
/// Returns `true` if this is a union.
#[inline]
pub fn is_union(&self) -> bool {
self.flags.contains(AdtFlags::IS_UNION)
}
/// Returns `true` if this is a enum.
#[inline]
pub fn is_enum(&self) -> bool {
self.flags.contains(AdtFlags::IS_ENUM)
}
/// Returns `true` if the variant list of this ADT is `#[non_exhaustive]`.
#[inline]
pub fn is_variant_list_non_exhaustive(&self) -> bool {
self.flags.contains(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
}
/// Returns the kind of the ADT.
#[inline]
pub fn adt_kind(&self) -> AdtKind {
if self.is_enum() {
AdtKind::Enum
} else if self.is_union() {
AdtKind::Union
} else {
AdtKind::Struct
}
}
/// Returns a description of this abstract data type.
pub fn descr(&self) -> &'static str {
match self.adt_kind() {
AdtKind::Struct => "struct",
AdtKind::Union => "union",
AdtKind::Enum => "enum",
}
}
/// Returns a description of a variant of this abstract data type.
#[inline]
pub fn variant_descr(&self) -> &'static str {
match self.adt_kind() {
AdtKind::Struct => "struct",
AdtKind::Union => "union",
AdtKind::Enum => "variant",
}
}
/// If this function returns `true`, it implies that `is_struct` must return `true`.
#[inline]
pub fn has_ctor(&self) -> bool {
self.flags.contains(AdtFlags::HAS_CTOR)
}
/// Returns `true` if this type is `#[fundamental]` for the purposes
/// of coherence checking.
#[inline]
pub fn is_fundamental(&self) -> bool {
self.flags.contains(AdtFlags::IS_FUNDAMENTAL)
}
/// Returns `true` if this is `PhantomData<T>`.
#[inline]
pub fn is_phantom_data(&self) -> bool {
self.flags.contains(AdtFlags::IS_PHANTOM_DATA)
}
/// Returns `true` if this is Box<T>.
#[inline]
pub fn is_box(&self) -> bool {
self.flags.contains(AdtFlags::IS_BOX)
}
/// Returns `true` if this is `ManuallyDrop<T>`.
#[inline]
pub fn is_manually_drop(&self) -> bool {
self.flags.contains(AdtFlags::IS_MANUALLY_DROP)
}
/// Returns `true` if this type has a destructor.
pub fn has_dtor(&self, tcx: TyCtxt<'tcx>) -> bool {
self.destructor(tcx).is_some()
}
/// Asserts this is a struct or union and returns its unique variant.
pub fn non_enum_variant(&self) -> &VariantDef {
assert!(self.is_struct() || self.is_union());
&self.variants[VariantIdx::new(0)]
}
#[inline]
pub fn predicates(&self, tcx: TyCtxt<'tcx>) -> GenericPredicates<'tcx> {
tcx.predicates_of(self.did)
}
/// Returns an iterator over all fields contained
/// by this ADT.
#[inline]
pub fn all_fields(&self) -> impl Iterator<Item = &FieldDef> + Clone {
self.variants.iter().flat_map(|v| v.fields.iter())
}
/// Whether the ADT lacks fields. Note that this includes uninhabited enums,
/// e.g., `enum Void {}` is considered payload free as well.
pub fn is_payloadfree(&self) -> bool {
self.variants.iter().all(|v| v.fields.is_empty())
}
/// Return a `VariantDef` given a variant id.
pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
self.variants.iter().find(|v| v.def_id == vid).expect("variant_with_id: unknown variant")
}
/// Return a `VariantDef` given a constructor id.
pub fn variant_with_ctor_id(&self, cid: DefId) -> &VariantDef {
self.variants
.iter()
.find(|v| v.ctor_def_id == Some(cid))
.expect("variant_with_ctor_id: unknown variant")
}
/// Return the index of `VariantDef` given a variant id.
pub fn variant_index_with_id(&self, vid: DefId) -> VariantIdx {
self.variants
.iter_enumerated()
.find(|(_, v)| v.def_id == vid)
.expect("variant_index_with_id: unknown variant")
.0
}
/// Return the index of `VariantDef` given a constructor id.
pub fn variant_index_with_ctor_id(&self, cid: DefId) -> VariantIdx {
self.variants
.iter_enumerated()
.find(|(_, v)| v.ctor_def_id == Some(cid))
.expect("variant_index_with_ctor_id: unknown variant")
.0
}
pub fn variant_of_res(&self, res: Res) -> &VariantDef {
match res {
Res::Def(DefKind::Variant, vid) => self.variant_with_id(vid),
Res::Def(DefKind::Ctor(..), cid) => self.variant_with_ctor_id(cid),
Res::Def(DefKind::Struct, _)
| Res::Def(DefKind::Union, _)
| Res::Def(DefKind::TyAlias, _)
| Res::Def(DefKind::AssocTy, _)
| Res::SelfTy(..)
| Res::SelfCtor(..) => self.non_enum_variant(),
_ => bug!("unexpected res {:?} in variant_of_res", res),
}
}
#[inline]
pub fn eval_explicit_discr(&self, tcx: TyCtxt<'tcx>, expr_did: DefId) -> Option<Discr<'tcx>> {
assert!(self.is_enum());
let param_env = tcx.param_env(expr_did);
let repr_type = self.repr.discr_type();
match tcx.const_eval_poly(expr_did) {
Ok(val) => {
let ty = repr_type.to_ty(tcx);
if let Some(b) = val.try_to_bits_for_ty(tcx, param_env, ty) {
trace!("discriminants: {} ({:?})", b, repr_type);
Some(Discr { val: b, ty })
} else {
info!("invalid enum discriminant: {:#?}", val);
crate::mir::interpret::struct_error(
tcx.at(tcx.def_span(expr_did)),
"constant evaluation of enum discriminant resulted in non-integer",
)
.emit();
None
}
}
Err(err) => {
let msg = match err {
ErrorHandled::Reported(ErrorReported) | ErrorHandled::Linted => {
"enum discriminant evaluation failed"
}
ErrorHandled::TooGeneric => "enum discriminant depends on generics",
};
tcx.sess.delay_span_bug(tcx.def_span(expr_did), msg);
None
}
}
}
#[inline]
pub fn discriminants(
&'tcx self,
tcx: TyCtxt<'tcx>,
) -> impl Iterator<Item = (VariantIdx, Discr<'tcx>)> + Captures<'tcx> {
assert!(self.is_enum());
let repr_type = self.repr.discr_type();
let initial = repr_type.initial_discriminant(tcx);
let mut prev_discr = None::<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> {
assert!(self.is_enum());
let (val, offset) = self.discriminant_def_for_variant(variant_index);
let explicit_value = val
.and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
.unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx));
explicit_value.checked_add(tcx, offset as u128).0
}
/// Yields a `DefId` for the discriminant and an offset to add to it
/// Alternatively, if there is no explicit discriminant, returns the
/// inferred discriminant directly.
pub fn discriminant_def_for_variant(&self, variant_index: VariantIdx) -> (Option<DefId>, u32) {
assert!(!self.variants.is_empty());
let mut explicit_index = variant_index.as_u32();
let expr_did;
loop {
match self.variants[VariantIdx::from_u32(explicit_index)].discr {
ty::VariantDiscr::Relative(0) => {
expr_did = None;
break;
}
ty::VariantDiscr::Relative(distance) => {
explicit_index -= distance;
}
ty::VariantDiscr::Explicit(did) => {
expr_did = Some(did);
break;
}
}
}
(expr_did, variant_index.as_u32() - explicit_index)
}
pub fn destructor(&self, tcx: TyCtxt<'tcx>) -> Option<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
}
}

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pub use self::AssocItemContainer::*;
use crate::ty;
use rustc_data_structures::sorted_map::SortedIndexMultiMap;
use rustc_hir as hir;
use rustc_hir::def::{DefKind, Namespace};
use rustc_hir::def_id::DefId;
use rustc_span::symbol::{Ident, Symbol};
use super::{TyCtxt, Visibility};
#[derive(Clone, Copy, PartialEq, Eq, Debug, HashStable, Hash)]
pub enum AssocItemContainer {
TraitContainer(DefId),
ImplContainer(DefId),
}
impl AssocItemContainer {
/// Asserts that this is the `DefId` of an associated item declared
/// in a trait, and returns the trait `DefId`.
pub fn assert_trait(&self) -> DefId {
match *self {
TraitContainer(id) => id,
_ => bug!("associated item has wrong container type: {:?}", self),
}
}
pub fn id(&self) -> DefId {
match *self {
TraitContainer(id) => id,
ImplContainer(id) => id,
}
}
}
#[derive(Copy, Clone, Debug, PartialEq, HashStable, Eq, Hash)]
pub struct AssocItem {
pub def_id: DefId,
#[stable_hasher(project(name))]
pub ident: Ident,
pub kind: AssocKind,
pub vis: Visibility,
pub defaultness: hir::Defaultness,
pub container: AssocItemContainer,
/// Whether this is a method with an explicit self
/// as its first parameter, allowing method calls.
pub fn_has_self_parameter: bool,
}
impl AssocItem {
pub fn signature(&self, tcx: TyCtxt<'_>) -> String {
match self.kind {
ty::AssocKind::Fn => {
// We skip the binder here because the binder would deanonymize all
// late-bound regions, and we don't want method signatures to show up
// `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
// regions just fine, showing `fn(&MyType)`.
tcx.fn_sig(self.def_id).skip_binder().to_string()
}
ty::AssocKind::Type => format!("type {};", self.ident),
ty::AssocKind::Const => {
format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id))
}
}
}
}
#[derive(Copy, Clone, PartialEq, Debug, HashStable, Eq, Hash)]
pub enum AssocKind {
Const,
Fn,
Type,
}
impl AssocKind {
pub fn namespace(&self) -> Namespace {
match *self {
ty::AssocKind::Type => Namespace::TypeNS,
ty::AssocKind::Const | ty::AssocKind::Fn => Namespace::ValueNS,
}
}
pub fn as_def_kind(&self) -> DefKind {
match self {
AssocKind::Const => DefKind::AssocConst,
AssocKind::Fn => DefKind::AssocFn,
AssocKind::Type => DefKind::AssocTy,
}
}
}
/// A list of `ty::AssocItem`s in definition order that allows for efficient lookup by name.
///
/// When doing lookup by name, we try to postpone hygienic comparison for as long as possible since
/// it is relatively expensive. Instead, items are indexed by `Symbol` and hygienic comparison is
/// done only on items with the same name.
#[derive(Debug, Clone, PartialEq, HashStable)]
pub struct AssociatedItems<'tcx> {
pub(super) items: SortedIndexMultiMap<u32, Symbol, &'tcx ty::AssocItem>,
}
impl<'tcx> AssociatedItems<'tcx> {
/// Constructs an `AssociatedItems` map from a series of `ty::AssocItem`s in definition order.
pub fn new(items_in_def_order: impl IntoIterator<Item = &'tcx ty::AssocItem>) -> Self {
let items = items_in_def_order.into_iter().map(|item| (item.ident.name, item)).collect();
AssociatedItems { items }
}
/// Returns a slice of associated items in the order they were defined.
///
/// New code should avoid relying on definition order. If you need a particular associated item
/// for a known trait, make that trait a lang item instead of indexing this array.
pub fn in_definition_order(&self) -> impl '_ + Iterator<Item = &ty::AssocItem> {
self.items.iter().map(|(_, v)| *v)
}
pub fn len(&self) -> usize {
self.items.len()
}
/// Returns an iterator over all associated items with the given name, ignoring hygiene.
pub fn filter_by_name_unhygienic(
&self,
name: Symbol,
) -> impl '_ + Iterator<Item = &ty::AssocItem> {
self.items.get_by_key(&name).copied()
}
/// Returns an iterator over all associated items with the given name.
///
/// Multiple items may have the same name if they are in different `Namespace`s. For example,
/// an associated type can have the same name as a method. Use one of the `find_by_name_and_*`
/// methods below if you know which item you are looking for.
pub fn filter_by_name(
&'a self,
tcx: TyCtxt<'a>,
ident: Ident,
parent_def_id: DefId,
) -> impl 'a + Iterator<Item = &'a ty::AssocItem> {
self.filter_by_name_unhygienic(ident.name)
.filter(move |item| tcx.hygienic_eq(ident, item.ident, parent_def_id))
}
/// Returns the associated item with the given name and `AssocKind`, if one exists.
pub fn find_by_name_and_kind(
&self,
tcx: TyCtxt<'_>,
ident: Ident,
kind: AssocKind,
parent_def_id: DefId,
) -> Option<&ty::AssocItem> {
self.filter_by_name_unhygienic(ident.name)
.filter(|item| item.kind == kind)
.find(|item| tcx.hygienic_eq(ident, item.ident, parent_def_id))
}
/// Returns the associated item with the given name in the given `Namespace`, if one exists.
pub fn find_by_name_and_namespace(
&self,
tcx: TyCtxt<'_>,
ident: Ident,
ns: Namespace,
parent_def_id: DefId,
) -> Option<&ty::AssocItem> {
self.filter_by_name_unhygienic(ident.name)
.filter(|item| item.kind.namespace() == ns)
.find(|item| tcx.hygienic_eq(ident, item.ident, parent_def_id))
}
}

338
compiler/rustc_middle/src/ty/closure.rs Normal file
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use crate::hir::place::{
Place as HirPlace, PlaceBase as HirPlaceBase, ProjectionKind as HirProjectionKind,
};
use crate::ty;
use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
use rustc_hir as hir;
use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_hir::lang_items::LangItem;
use rustc_span::Span;
use super::{Ty, TyCtxt};
use self::BorrowKind::*;
#[derive(
Clone,
Copy,
Debug,
PartialEq,
Eq,
Hash,
TyEncodable,
TyDecodable,
TypeFoldable,
HashStable
)]
pub struct UpvarPath {
pub hir_id: hir::HirId,
}
/// Upvars do not get their own `NodeId`. Instead, we use the pair of
/// the original var ID (that is, the root variable that is referenced
/// by the upvar) and the ID of the closure expression.
#[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable, TypeFoldable, HashStable)]
pub struct UpvarId {
pub var_path: UpvarPath,
pub closure_expr_id: LocalDefId,
}
impl UpvarId {
pub fn new(var_hir_id: hir::HirId, closure_def_id: LocalDefId) -> UpvarId {
UpvarId { var_path: UpvarPath { hir_id: var_hir_id }, closure_expr_id: closure_def_id }
}
}
/// Information describing the capture of an upvar. This is computed
/// during `typeck`, specifically by `regionck`.
#[derive(PartialEq, Clone, Debug, Copy, TyEncodable, TyDecodable, TypeFoldable, HashStable)]
pub enum UpvarCapture<'tcx> {
/// Upvar is captured by value. This is always true when the
/// closure is labeled `move`, but can also be true in other cases
/// depending on inference.
///
/// If the upvar was inferred to be captured by value (e.g. `move`
/// was not used), then the `Span` points to a usage that
/// required it. There may be more than one such usage
/// (e.g. `|| { a; a; }`), in which case we pick an
/// arbitrary one.
ByValue(Option<Span>),
/// Upvar is captured by reference.
ByRef(UpvarBorrow<'tcx>),
}
#[derive(PartialEq, Clone, Copy, TyEncodable, TyDecodable, TypeFoldable, 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>>;
/// Given the closure DefId this map provides a map of root variables to minimum
/// set of `CapturedPlace`s that need to be tracked to support all captures of that closure.
pub type MinCaptureInformationMap<'tcx> = FxHashMap<DefId, RootVariableMinCaptureList<'tcx>>;
/// Part of `MinCaptureInformationMap`; Maps a root variable to the list of `CapturedPlace`.
/// Used to track the minimum set of `Place`s that need to be captured to support all
/// Places captured by the closure starting at a given root variable.
///
/// This provides a convenient and quick way of checking if a variable being used within
/// a closure is a capture of a local variable.
pub type RootVariableMinCaptureList<'tcx> = FxIndexMap<hir::HirId, MinCaptureList<'tcx>>;
/// Part of `MinCaptureInformationMap`; List of `CapturePlace`s.
pub type MinCaptureList<'tcx> = Vec<CapturedPlace<'tcx>>;
/// Represents the various closure traits in the language. This
/// will determine the type of the environment (`self`, in the
/// desugaring) argument that the closure expects.
///
/// You can get the environment type of a closure using
/// `tcx.closure_env_ty()`.
#[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, TyEncodable, TyDecodable)]
#[derive(HashStable)]
pub enum ClosureKind {
// Warning: Ordering is significant here! The ordering is chosen
// because the trait Fn is a subtrait of FnMut and so in turn, and
// hence we order it so that Fn < FnMut < FnOnce.
Fn,
FnMut,
FnOnce,
}
impl<'tcx> ClosureKind {
// This is the initial value used when doing upvar inference.
pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
pub fn trait_did(&self, tcx: TyCtxt<'tcx>) -> DefId {
match *self {
ClosureKind::Fn => tcx.require_lang_item(LangItem::Fn, None),
ClosureKind::FnMut => tcx.require_lang_item(LangItem::FnMut, None),
ClosureKind::FnOnce => tcx.require_lang_item(LangItem::FnOnce, None),
}
}
/// Returns `true` if a type that impls this closure kind
/// must also implement `other`.
pub fn extends(self, other: ty::ClosureKind) -> bool {
matches!(
(self, other),
(ClosureKind::Fn, ClosureKind::Fn)
| (ClosureKind::Fn, ClosureKind::FnMut)
| (ClosureKind::Fn, ClosureKind::FnOnce)
| (ClosureKind::FnMut, ClosureKind::FnMut)
| (ClosureKind::FnMut, ClosureKind::FnOnce)
| (ClosureKind::FnOnce, ClosureKind::FnOnce)
)
}
/// Returns the representative scalar type for this closure kind.
/// See `TyS::to_opt_closure_kind` for more details.
pub fn to_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
match self {
ty::ClosureKind::Fn => tcx.types.i8,
ty::ClosureKind::FnMut => tcx.types.i16,
ty::ClosureKind::FnOnce => tcx.types.i32,
}
}
}
/// A composite describing a `Place` that is captured by a closure.
#[derive(PartialEq, Clone, Debug, TyEncodable, TyDecodable, TypeFoldable, HashStable)]
pub struct CapturedPlace<'tcx> {
/// The `Place` that is captured.
pub place: HirPlace<'tcx>,
/// `CaptureKind` and expression(s) that resulted in such capture of `place`.
pub info: CaptureInfo<'tcx>,
/// Represents if `place` can be mutated or not.
pub mutability: hir::Mutability,
}
impl CapturedPlace<'tcx> {
/// Returns the hir-id of the root variable for the captured place.
/// e.g., if `a.b.c` was captured, would return the hir-id for `a`.
pub fn get_root_variable(&self) -> hir::HirId {
match self.place.base {
HirPlaceBase::Upvar(upvar_id) => upvar_id.var_path.hir_id,
base => bug!("Expected upvar, found={:?}", base),
}
}
}
/// Part of `MinCaptureInformationMap`; describes the capture kind (&, &mut, move)
/// for a particular capture as well as identifying the part of the source code
/// that triggered this capture to occur.
#[derive(PartialEq, Clone, Debug, Copy, TyEncodable, TyDecodable, TypeFoldable, HashStable)]
pub struct CaptureInfo<'tcx> {
/// Expr Id pointing to use that resulted in selecting the current capture kind
///
/// Eg:
/// ```rust,no_run
/// let mut t = (0,1);
///
/// let c = || {
/// println!("{}",t); // L1
/// t.1 = 4; // L2
/// };
/// ```
/// `capture_kind_expr_id` will point to the use on L2 and `path_expr_id` will point to the
/// use on L1.
///
/// If the user doesn't enable feature `capture_disjoint_fields` (RFC 2229) then, it is
/// possible that we don't see the use of a particular place resulting in capture_kind_expr_id being
/// None. In such case we fallback on uvpars_mentioned for span.
///
/// Eg:
/// ```rust,no_run
/// let x = 5;
///
/// let c = || {
/// let _ = x
/// };
/// ```
///
/// In this example, if `capture_disjoint_fields` is **not** set, then x will be captured,
/// but we won't see it being used during capture analysis, since it's essentially a discard.
pub capture_kind_expr_id: Option<hir::HirId>,
/// Expr Id pointing to use that resulted the corresponding place being captured
///
/// See `capture_kind_expr_id` for example.
///
pub path_expr_id: Option<hir::HirId>,
/// Capture mode that was selected
pub capture_kind: UpvarCapture<'tcx>,
}
pub fn place_to_string_for_capture(tcx: TyCtxt<'tcx>, place: &HirPlace<'tcx>) -> String {
let name = match place.base {
HirPlaceBase::Upvar(upvar_id) => tcx.hir().name(upvar_id.var_path.hir_id).to_string(),
_ => bug!("Capture_information should only contain upvars"),
};
let mut curr_string = name;
for (i, proj) in place.projections.iter().enumerate() {
match proj.kind {
HirProjectionKind::Deref => {
curr_string = format!("*{}", curr_string);
}
HirProjectionKind::Field(idx, variant) => match place.ty_before_projection(i).kind() {
ty::Adt(def, ..) => {
curr_string = format!(
"{}.{}",
curr_string,
def.variants[variant].fields[idx as usize].ident.name.as_str()
);
}
ty::Tuple(_) => {
curr_string = format!("{}.{}", curr_string, idx);
}
_ => {
bug!(
"Field projection applied to a type other than Adt or Tuple: {:?}.",
place.ty_before_projection(i).kind()
)
}
},
proj => bug!("{:?} unexpected because it isn't captured", proj),
}
}
curr_string.to_string()
}
#[derive(Clone, PartialEq, Debug, TyEncodable, TyDecodable, TypeFoldable, 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,
}
impl BorrowKind {
pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
match m {
hir::Mutability::Mut => MutBorrow,
hir::Mutability::Not => ImmBorrow,
}
}
/// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
/// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
/// mutability that is stronger than necessary so that it at least *would permit* the borrow in
/// question.
pub fn to_mutbl_lossy(self) -> hir::Mutability {
match self {
MutBorrow => hir::Mutability::Mut,
ImmBorrow => hir::Mutability::Not,
// We have no type corresponding to a unique imm borrow, so
// use `&mut`. It gives all the capabilities of an `&uniq`
// and hence is a safe "over approximation".
UniqueImmBorrow => hir::Mutability::Mut,
}
}
pub fn to_user_str(&self) -> &'static str {
match *self {
MutBorrow => "mutable",
ImmBorrow => "immutable",
UniqueImmBorrow => "uniquely immutable",
}
}
}

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use crate::middle::resolve_lifetime::ObjectLifetimeDefault;
use crate::ty;
use crate::ty::subst::{Subst, SubstsRef};
use rustc_ast as ast;
use rustc_data_structures::fx::FxHashMap;
use rustc_hir as hir;
use rustc_hir::def_id::DefId;
use rustc_span::symbol::Symbol;
use rustc_span::Span;
use super::{EarlyBoundRegion, InstantiatedPredicates, ParamConst, ParamTy, Predicate, TyCtxt};
#[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable)]
pub enum GenericParamDefKind {
Lifetime,
Type {
has_default: bool,
object_lifetime_default: ObjectLifetimeDefault,
synthetic: Option<hir::SyntheticTyParamKind>,
},
Const,
}
impl GenericParamDefKind {
pub fn descr(&self) -> &'static str {
match self {
GenericParamDefKind::Lifetime => "lifetime",
GenericParamDefKind::Type { .. } => "type",
GenericParamDefKind::Const => "constant",
}
}
pub fn to_ord(&self, tcx: TyCtxt<'_>) -> ast::ParamKindOrd {
match self {
GenericParamDefKind::Lifetime => ast::ParamKindOrd::Lifetime,
GenericParamDefKind::Type { .. } => ast::ParamKindOrd::Type,
GenericParamDefKind::Const => {
ast::ParamKindOrd::Const { unordered: tcx.features().const_generics }
}
}
}
}
#[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable)]
pub struct GenericParamDef {
pub name: Symbol,
pub def_id: DefId,
pub index: u32,
/// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
/// on generic parameter `'a`/`T`, asserts data behind the parameter
/// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
pub pure_wrt_drop: bool,
pub kind: GenericParamDefKind,
}
impl GenericParamDef {
pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
if let GenericParamDefKind::Lifetime = self.kind {
ty::EarlyBoundRegion { def_id: self.def_id, index: self.index, name: self.name }
} else {
bug!("cannot convert a non-lifetime parameter def to an early bound region")
}
}
}
#[derive(Default)]
pub struct GenericParamCount {
pub lifetimes: usize,
pub types: usize,
pub consts: usize,
}
/// Information about the formal type/lifetime parameters associated
/// with an item or method. Analogous to `hir::Generics`.
///
/// The ordering of parameters is the same as in `Subst` (excluding child generics):
/// `Self` (optionally), `Lifetime` params..., `Type` params...
#[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable)]
pub struct Generics {
pub parent: Option<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();
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 own_defaults(&self) -> GenericParamCount {
let mut own_defaults = GenericParamCount::default();
for param in &self.params {
match param.kind {
GenericParamDefKind::Lifetime => (),
GenericParamDefKind::Type { has_default, .. } => {
own_defaults.types += has_default as usize;
}
GenericParamDefKind::Const => {
// FIXME(const_generics:defaults)
}
}
}
own_defaults
}
pub fn requires_monomorphization(&self, tcx: TyCtxt<'tcx>) -> bool {
if self.own_requires_monomorphization() {
return true;
}
if let Some(parent_def_id) = self.parent {
let parent = tcx.generics_of(parent_def_id);
parent.requires_monomorphization(tcx)
} else {
false
}
}
pub fn own_requires_monomorphization(&self) -> bool {
for param in &self.params {
match param.kind {
GenericParamDefKind::Type { .. } | GenericParamDefKind::Const => return true,
GenericParamDefKind::Lifetime => {}
}
}
false
}
/// Returns the `GenericParamDef` with the given index.
pub fn param_at(&'tcx self, param_index: usize, tcx: TyCtxt<'tcx>) -> &'tcx GenericParamDef {
if let Some(index) = param_index.checked_sub(self.parent_count) {
&self.params[index]
} else {
tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
.param_at(param_index, tcx)
}
}
/// Returns the `GenericParamDef` associated with this `EarlyBoundRegion`.
pub fn region_param(
&'tcx self,
param: &EarlyBoundRegion,
tcx: TyCtxt<'tcx>,
) -> &'tcx GenericParamDef {
let param = self.param_at(param.index as usize, tcx);
match param.kind {
GenericParamDefKind::Lifetime => param,
_ => bug!("expected lifetime parameter, but found another generic parameter"),
}
}
/// Returns the `GenericParamDef` associated with this `ParamTy`.
pub fn type_param(&'tcx self, param: &ParamTy, tcx: TyCtxt<'tcx>) -> &'tcx GenericParamDef {
let param = self.param_at(param.index as usize, tcx);
match param.kind {
GenericParamDefKind::Type { .. } => param,
_ => bug!("expected type parameter, but found another generic parameter"),
}
}
/// Returns the `GenericParamDef` associated with this `ParamConst`.
pub fn const_param(&'tcx self, param: &ParamConst, tcx: TyCtxt<'tcx>) -> &GenericParamDef {
let param = self.param_at(param.index as usize, tcx);
match param.kind {
GenericParamDefKind::Const => param,
_ => bug!("expected const parameter, but found another generic parameter"),
}
}
}
/// Bounds on generics.
#[derive(Copy, Clone, Default, Debug, TyEncodable, TyDecodable, HashStable)]
pub struct GenericPredicates<'tcx> {
pub parent: Option<DefId>,
pub predicates: &'tcx [(Predicate<'tcx>, Span)],
}
impl<'tcx> GenericPredicates<'tcx> {
pub fn instantiate(
&self,
tcx: TyCtxt<'tcx>,
substs: SubstsRef<'tcx>,
) -> InstantiatedPredicates<'tcx> {
let mut instantiated = InstantiatedPredicates::empty();
self.instantiate_into(tcx, &mut instantiated, substs);
instantiated
}
pub fn instantiate_own(
&self,
tcx: TyCtxt<'tcx>,
substs: SubstsRef<'tcx>,
) -> InstantiatedPredicates<'tcx> {
InstantiatedPredicates {
predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
spans: self.predicates.iter().map(|(_, sp)| *sp).collect(),
}
}
fn instantiate_into(
&self,
tcx: TyCtxt<'tcx>,
instantiated: &mut InstantiatedPredicates<'tcx>,
substs: SubstsRef<'tcx>,
) {
if let Some(def_id) = self.parent {
tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
}
instantiated.predicates.extend(self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)));
instantiated.spans.extend(self.predicates.iter().map(|(_, sp)| *sp));
}
pub fn instantiate_identity(&self, tcx: TyCtxt<'tcx>) -> InstantiatedPredicates<'tcx> {
let mut instantiated = InstantiatedPredicates::empty();
self.instantiate_identity_into(tcx, &mut instantiated);
instantiated
}
fn instantiate_identity_into(
&self,
tcx: TyCtxt<'tcx>,
instantiated: &mut InstantiatedPredicates<'tcx>,
) {
if let Some(def_id) = self.parent {
tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
}
instantiated.predicates.extend(self.predicates.iter().map(|(p, _)| p));
instantiated.spans.extend(self.predicates.iter().map(|(_, s)| s));
}
}

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