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Rollup merge of #139669 - nnethercote:overhaul-AssocItem, r=oli-obk

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Overhaul `AssocItem`

`AssocItem` has multiple fields that only make sense some of the time. E.g. the `name` can be empty if it's an RPITIT associated type. It's clearer and less error prone if these fields are moved to the relevant `kind` variants.

r? ``@fee1-dead``
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Stuart Cook 2025-04-15 15:47:27 +10:00 • committed by GitHub
commit 13cd5256ac
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86 changed files with 609 additions and 546 deletions
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4
compiler/rustc_middle/src/mir/mod.rs
View file

@ -1636,8 +1636,8 @@ pub fn find_self_call<'tcx>(
&body[block].terminator
&& let Operand::Constant(box ConstOperand { const_, .. }) = func
&& let ty::FnDef(def_id, fn_args) = *const_.ty().kind()
&& let Some(ty::AssocItem { fn_has_self_parameter: true, .. }) =
tcx.opt_associated_item(def_id)
&& let Some(item) = tcx.opt_associated_item(def_id)
&& item.is_method()
&& let [Spanned { node: Operand::Move(self_place) | Operand::Copy(self_place), .. }, ..] =
**args
{

4
compiler/rustc_middle/src/ty/adjustment.rs
View file

@ -5,7 +5,7 @@ use rustc_hir::lang_items::LangItem;
use rustc_macros::{HashStable, TyDecodable, TyEncodable, TypeFoldable, TypeVisitable};
use rustc_span::Span;
use crate::ty::{self, Ty, TyCtxt};
use crate::ty::{Ty, TyCtxt};
#[derive(Clone, Copy, Debug, PartialEq, Eq, TyEncodable, TyDecodable, Hash, HashStable)]
pub enum PointerCoercion {
@ -133,7 +133,7 @@ impl OverloadedDeref {
};
tcx.associated_items(trait_def_id)
.in_definition_order()
.find(|m| m.kind == ty::AssocKind::Fn)
.find(|item| item.is_fn())
.unwrap()
.def_id
}

156
compiler/rustc_middle/src/ty/assoc.rs
View file

@ -18,27 +18,33 @@ pub enum AssocItemContainer {
#[derive(Copy, Clone, Debug, PartialEq, HashStable, Eq, Hash, Encodable, Decodable)]
pub struct AssocItem {
pub def_id: DefId,
pub name: Symbol,
pub kind: AssocKind,
pub container: AssocItemContainer,
/// If this is an item in an impl of a trait then this is the `DefId` of
/// the associated item on the trait that this implements.
pub trait_item_def_id: Option<DefId>,
/// Whether this is a method with an explicit self
/// as its first parameter, allowing method calls.
pub fn_has_self_parameter: bool,
/// `Some` if the associated item (an associated type) comes from the
/// return-position `impl Trait` in trait desugaring. The `ImplTraitInTraitData`
/// provides additional information about its source.
pub opt_rpitit_info: Option<ty::ImplTraitInTraitData>,
}
impl AssocItem {
// Gets the identifier, if it has one.
pub fn opt_name(&self) -> Option<Symbol> {
match self.kind {
ty::AssocKind::Type { data: AssocTypeData::Normal(name) } => Some(name),
ty::AssocKind::Type { data: AssocTypeData::Rpitit(_) } => None,
ty::AssocKind::Const { name } => Some(name),
ty::AssocKind::Fn { name, .. } => Some(name),
}
}
// Gets the identifier name. Aborts if it lacks one, i.e. is an RPITIT
// associated type.
pub fn name(&self) -> Symbol {
self.opt_name().expect("name of non-Rpitit assoc item")
}
pub fn ident(&self, tcx: TyCtxt<'_>) -> Ident {
Ident::new(self.name, tcx.def_ident_span(self.def_id).unwrap())
Ident::new(self.name(), tcx.def_ident_span(self.def_id).unwrap())
}
/// Gets the defaultness of the associated item.
@ -78,35 +84,65 @@ impl AssocItem {
pub fn signature(&self, tcx: TyCtxt<'_>) -> String {
match self.kind {
ty::AssocKind::Fn => {
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).instantiate_identity().skip_binder().to_string()
}
ty::AssocKind::Type => format!("type {};", self.name),
ty::AssocKind::Const => {
format!(
"const {}: {:?};",
self.name,
tcx.type_of(self.def_id).instantiate_identity()
)
ty::AssocKind::Type { .. } => format!("type {};", self.name()),
ty::AssocKind::Const { name } => {
format!("const {}: {:?};", name, tcx.type_of(self.def_id).instantiate_identity())
}
}
}
pub fn descr(&self) -> &'static str {
match self.kind {
ty::AssocKind::Const => "associated const",
ty::AssocKind::Fn if self.fn_has_self_parameter => "method",
ty::AssocKind::Fn => "associated function",
ty::AssocKind::Type => "associated type",
ty::AssocKind::Const { .. } => "associated const",
ty::AssocKind::Fn { has_self: true, .. } => "method",
ty::AssocKind::Fn { has_self: false, .. } => "associated function",
ty::AssocKind::Type { .. } => "associated type",
}
}
pub fn namespace(&self) -> Namespace {
match self.kind {
ty::AssocKind::Type { .. } => Namespace::TypeNS,
ty::AssocKind::Const { .. } | ty::AssocKind::Fn { .. } => Namespace::ValueNS,
}
}
pub fn as_def_kind(&self) -> DefKind {
match self.kind {
AssocKind::Const { .. } => DefKind::AssocConst,
AssocKind::Fn { .. } => DefKind::AssocFn,
AssocKind::Type { .. } => DefKind::AssocTy,
}
}
pub fn is_type(&self) -> bool {
matches!(self.kind, ty::AssocKind::Type { .. })
}
pub fn is_fn(&self) -> bool {
matches!(self.kind, ty::AssocKind::Fn { .. })
}
pub fn is_method(&self) -> bool {
matches!(self.kind, ty::AssocKind::Fn { has_self: true, .. })
}
pub fn as_tag(&self) -> AssocTag {
match self.kind {
AssocKind::Const { .. } => AssocTag::Const,
AssocKind::Fn { .. } => AssocTag::Fn,
AssocKind::Type { .. } => AssocTag::Type,
}
}
pub fn is_impl_trait_in_trait(&self) -> bool {
self.opt_rpitit_info.is_some()
matches!(self.kind, AssocKind::Type { data: AssocTypeData::Rpitit(_) })
}
/// Returns true if:
@ -114,7 +150,7 @@ impl AssocItem {
/// - If it is in a trait impl, the item from the original trait has this attribute, or
/// - It is an inherent assoc const.
pub fn is_type_const_capable(&self, tcx: TyCtxt<'_>) -> bool {
if self.kind != ty::AssocKind::Const {
if !matches!(self.kind, ty::AssocKind::Const { .. }) {
return false;
}
@ -128,26 +164,35 @@ impl AssocItem {
}
}
#[derive(Copy, Clone, PartialEq, Debug, HashStable, Eq, Hash, Encodable, Decodable)]
pub enum AssocTypeData {
Normal(Symbol),
/// The associated type comes from an RPITIT. It has no name, and the
/// `ImplTraitInTraitData` provides additional information about its
/// source.
Rpitit(ty::ImplTraitInTraitData),
}
#[derive(Copy, Clone, PartialEq, Debug, HashStable, Eq, Hash, Encodable, Decodable)]
pub enum AssocKind {
Const,
Fn,
Type,
Const { name: Symbol },
Fn { name: Symbol, has_self: bool },
Type { data: AssocTypeData },
}
impl AssocKind {
pub fn namespace(&self) -> Namespace {
match *self {
ty::AssocKind::Type => Namespace::TypeNS,
ty::AssocKind::Const | ty::AssocKind::Fn => Namespace::ValueNS,
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,
AssocKind::Const { .. } => DefKind::AssocConst,
AssocKind::Fn { .. } => DefKind::AssocFn,
AssocKind::Type { .. } => DefKind::AssocTy,
}
}
}
@ -155,15 +200,22 @@ impl AssocKind {
impl std::fmt::Display for AssocKind {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
// FIXME: fails to distinguish between "associated function" and
// "method" because `has_self` isn't known here.
AssocKind::Fn => write!(f, "method"),
AssocKind::Const => write!(f, "associated const"),
AssocKind::Type => write!(f, "associated type"),
AssocKind::Fn { has_self: true, .. } => write!(f, "method"),
AssocKind::Fn { has_self: false, .. } => write!(f, "associated function"),
AssocKind::Const { .. } => write!(f, "associated const"),
AssocKind::Type { .. } => write!(f, "associated type"),
}
}
}
// Like `AssocKind`, but just the tag, no fields. Used in various kinds of matching.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum AssocTag {
Const,
Fn,
Type,
}
/// 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
@ -171,17 +223,17 @@ impl std::fmt::Display for AssocKind {
/// done only on items with the same name.
#[derive(Debug, Clone, PartialEq, HashStable)]
pub struct AssocItems {
items: SortedIndexMultiMap<u32, Symbol, ty::AssocItem>,
items: SortedIndexMultiMap<u32, Option<Symbol>, ty::AssocItem>,
}
impl AssocItems {
/// Constructs an `AssociatedItems` map from a series of `ty::AssocItem`s in definition order.
pub fn new(items_in_def_order: impl IntoIterator<Item = ty::AssocItem>) -> Self {
let items = items_in_def_order.into_iter().map(|item| (item.name, item)).collect();
let items = items_in_def_order.into_iter().map(|item| (item.opt_name(), item)).collect();
AssocItems { items }
}
/// Returns a slice of associated items in the order they were defined.
/// Returns an iterator over 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.
@ -198,7 +250,8 @@ impl AssocItems {
&self,
name: Symbol,
) -> impl '_ + Iterator<Item = &ty::AssocItem> {
self.items.get_by_key(name)
assert!(!name.is_empty());
self.items.get_by_key(Some(name))
}
/// Returns the associated item with the given identifier and `AssocKind`, if one exists.
@ -207,27 +260,14 @@ impl AssocItems {
&self,
tcx: TyCtxt<'_>,
ident: Ident,
kind: AssocKind,
assoc_tag: AssocTag,
parent_def_id: DefId,
) -> Option<&ty::AssocItem> {
self.filter_by_name_unhygienic(ident.name)
.filter(|item| item.kind == kind)
.filter(|item| item.as_tag() == assoc_tag)
.find(|item| tcx.hygienic_eq(ident, item.ident(tcx), parent_def_id))
}
/// Returns the associated item with the given identifier and any of `AssocKind`, if one
/// exists. The identifier is matched hygienically.
pub fn find_by_ident_and_kinds(
&self,
tcx: TyCtxt<'_>,
ident: Ident,
// Sorted in order of what kinds to look at
kinds: &[AssocKind],
parent_def_id: DefId,
) -> Option<&ty::AssocItem> {
kinds.iter().find_map(|kind| self.find_by_ident_and_kind(tcx, ident, *kind, parent_def_id))
}
/// Returns the associated item with the given identifier in the given `Namespace`, if one
/// exists. The identifier is matched hygienically.
pub fn find_by_ident_and_namespace(
@ -238,7 +278,7 @@ impl AssocItems {
parent_def_id: DefId,
) -> Option<&ty::AssocItem> {
self.filter_by_name_unhygienic(ident.name)
.filter(|item| item.kind.namespace() == ns)
.filter(|item| item.namespace() == ns)
.find(|item| tcx.hygienic_eq(ident, item.ident(tcx), parent_def_id))
}
}

2
compiler/rustc_middle/src/ty/context.rs
View file

@ -464,7 +464,7 @@ impl<'tcx> Interner for TyCtxt<'tcx> {
fn associated_type_def_ids(self, def_id: DefId) -> impl IntoIterator<Item = DefId> {
self.associated_items(def_id)
.in_definition_order()
.filter(|assoc_item| matches!(assoc_item.kind, ty::AssocKind::Type))
.filter(|assoc_item| assoc_item.is_type())
.map(|assoc_item| assoc_item.def_id)
}

2
compiler/rustc_middle/src/ty/instance.rs
View file

@ -746,7 +746,7 @@ impl<'tcx> Instance<'tcx> {
let call_once = tcx
.associated_items(fn_once)
.in_definition_order()
.find(|it| it.kind == ty::AssocKind::Fn)
.find(|it| it.is_fn())
.unwrap()
.def_id;
let track_caller =

9
compiler/rustc_middle/src/ty/mod.rs
View file

@ -1462,7 +1462,7 @@ impl<'tcx> TyCtxt<'tcx> {
pub fn provided_trait_methods(self, id: DefId) -> impl 'tcx + Iterator<Item = &'tcx AssocItem> {
self.associated_items(id)
.in_definition_order()
.filter(move |item| item.kind == AssocKind::Fn && item.defaultness(self).has_value())
.filter(move |item| item.is_fn() && item.defaultness(self).has_value())
}
pub fn repr_options_of_def(self, did: LocalDefId) -> ReprOptions {
@ -1608,8 +1608,11 @@ impl<'tcx> TyCtxt<'tcx> {
/// return-position `impl Trait` from a trait, then provide the source info
/// about where that RPITIT came from.
pub fn opt_rpitit_info(self, def_id: DefId) -> Option<ImplTraitInTraitData> {
if let DefKind::AssocTy = self.def_kind(def_id) {
self.associated_item(def_id).opt_rpitit_info
if let DefKind::AssocTy = self.def_kind(def_id)
&& let AssocKind::Type { data: AssocTypeData::Rpitit(rpitit_info) } =
self.associated_item(def_id).kind
{
Some(rpitit_info)
} else {
None
}

6
compiler/rustc_middle/src/ty/print/pretty.rs
View file

@ -1214,7 +1214,7 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
&& assoc
.trait_container(tcx)
.is_some_and(|def_id| tcx.is_lang_item(def_id, LangItem::Coroutine))
&& assoc.name == rustc_span::sym::Return
&& assoc.opt_name() == Some(rustc_span::sym::Return)
{
if let ty::Coroutine(_, args) = args.type_at(0).kind() {
let return_ty = args.as_coroutine().return_ty();
@ -1237,7 +1237,7 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
p!(", ");
}
p!(write("{} = ", tcx.associated_item(assoc_item_def_id).name));
p!(write("{} = ", tcx.associated_item(assoc_item_def_id).name()));
match term.unpack() {
TermKind::Ty(ty) => p!(print(ty)),
@ -3291,7 +3291,7 @@ define_print! {
}
ty::ExistentialProjection<'tcx> {
let name = cx.tcx().associated_item(self.def_id).name;
let name = cx.tcx().associated_item(self.def_id).name();
// The args don't contain the self ty (as it has been erased) but the corresp.
// generics do as the trait always has a self ty param. We need to offset.
let args = &self.args[cx.tcx().generics_of(self.def_id).parent_count - 1..];

2
compiler/rustc_middle/src/ty/sty.rs
View file

@ -735,7 +735,7 @@ impl<'tcx> Ty<'tcx> {
.map(|principal| {
tcx.associated_items(principal.def_id())
.in_definition_order()
.filter(|item| item.kind == ty::AssocKind::Type)
.filter(|item| item.is_type())
.filter(|item| !item.is_impl_trait_in_trait())
.filter(|item| !tcx.generics_require_sized_self(item.def_id))
.count()

4
compiler/rustc_middle/src/ty/util.rs
View file

@ -819,7 +819,7 @@ impl<'tcx> TyCtxt<'tcx> {
/// Get an English description for the item's kind.
pub fn def_kind_descr(self, def_kind: DefKind, def_id: DefId) -> &'static str {
match def_kind {
DefKind::AssocFn if self.associated_item(def_id).fn_has_self_parameter => "method",
DefKind::AssocFn if self.associated_item(def_id).is_method() => "method",
DefKind::Closure if let Some(coroutine_kind) = self.coroutine_kind(def_id) => {
match coroutine_kind {
hir::CoroutineKind::Desugared(
@ -873,7 +873,7 @@ impl<'tcx> TyCtxt<'tcx> {
/// Gets an English article for the [`TyCtxt::def_kind_descr`].
pub fn def_kind_descr_article(self, def_kind: DefKind, def_id: DefId) -> &'static str {
match def_kind {
DefKind::AssocFn if self.associated_item(def_id).fn_has_self_parameter => "a",
DefKind::AssocFn if self.associated_item(def_id).is_method() => "a",
DefKind::Closure if let Some(coroutine_kind) = self.coroutine_kind(def_id) => {
match coroutine_kind {
hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Async, ..) => "an",