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Rollup merge of #124135 - petrochenkov:deleglob, r=fmease

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delegation: Implement glob delegation

Support delegating to all trait methods in one go.
Overriding globs with explicit definitions is also supported.

The implementation is generally based on the design from https://github.com/rust-lang/rfcs/pull/3530#issuecomment-2020869823, but unlike with list delegation in https://github.com/rust-lang/rust/pull/123413 we cannot expand glob delegation eagerly.
We have to enqueue it into the queue of unexpanded macros (most other macros are processed this way too), and then a glob delegation waits in that queue until its trait path is resolved, and enough code expands to generate the identifier list produced from the glob.

Glob delegation is only allowed in impls, and can only point to traits.
Supporting it in other places gives very little practical benefit, but significantly raises the implementation complexity.

Part of https://github.com/rust-lang/rust/issues/118212.
This commit is contained in:
许杰友 Jieyou Xu (Joe) 2024-06-19 01:51:36 +01:00 • committed by GitHub
commit f8ce1cfbf5
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29 changed files with 878 additions and 123 deletions
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47
compiler/rustc_expand/src/base.rs
View file

@ -357,6 +357,10 @@ where
}
}
pub trait GlobDelegationExpander {
fn expand(&self, ecx: &mut ExtCtxt<'_>) -> ExpandResult<Vec<(Ident, Option<Ident>)>, ()>;
}
// Use a macro because forwarding to a simple function has type system issues
macro_rules! make_stmts_default {
($me:expr) => {
@ -714,6 +718,9 @@ pub enum SyntaxExtensionKind {
/// The produced AST fragment is appended to the input AST fragment.
Box<dyn MultiItemModifier + sync::DynSync + sync::DynSend>,
),
/// A glob delegation.
GlobDelegation(Box<dyn GlobDelegationExpander + sync::DynSync + sync::DynSend>),
}
/// A struct representing a macro definition in "lowered" form ready for expansion.
@ -748,7 +755,9 @@ impl SyntaxExtension {
/// Returns which kind of macro calls this syntax extension.
pub fn macro_kind(&self) -> MacroKind {
match self.kind {
SyntaxExtensionKind::Bang(..) | SyntaxExtensionKind::LegacyBang(..) => MacroKind::Bang,
SyntaxExtensionKind::Bang(..)
| SyntaxExtensionKind::LegacyBang(..)
| SyntaxExtensionKind::GlobDelegation(..) => MacroKind::Bang,
SyntaxExtensionKind::Attr(..)
| SyntaxExtensionKind::LegacyAttr(..)
| SyntaxExtensionKind::NonMacroAttr => MacroKind::Attr,
@ -922,6 +931,32 @@ impl SyntaxExtension {
SyntaxExtension::default(SyntaxExtensionKind::NonMacroAttr, edition)
}
pub fn glob_delegation(
trait_def_id: DefId,
impl_def_id: LocalDefId,
edition: Edition,
) -> SyntaxExtension {
struct GlobDelegationExpanderImpl {
trait_def_id: DefId,
impl_def_id: LocalDefId,
}
impl GlobDelegationExpander for GlobDelegationExpanderImpl {
fn expand(
&self,
ecx: &mut ExtCtxt<'_>,
) -> ExpandResult<Vec<(Ident, Option<Ident>)>, ()> {
match ecx.resolver.glob_delegation_suffixes(self.trait_def_id, self.impl_def_id) {
Ok(suffixes) => ExpandResult::Ready(suffixes),
Err(Indeterminate) if ecx.force_mode => ExpandResult::Ready(Vec::new()),
Err(Indeterminate) => ExpandResult::Retry(()),
}
}
}
let expander = GlobDelegationExpanderImpl { trait_def_id, impl_def_id };
SyntaxExtension::default(SyntaxExtensionKind::GlobDelegation(Box::new(expander)), edition)
}
pub fn expn_data(
&self,
parent: LocalExpnId,
@ -1030,6 +1065,16 @@ pub trait ResolverExpand {
/// Tools registered with `#![register_tool]` and used by tool attributes and lints.
fn registered_tools(&self) -> &RegisteredTools;
/// Mark this invocation id as a glob delegation.
fn register_glob_delegation(&mut self, invoc_id: LocalExpnId);
/// Names of specific methods to which glob delegation expands.
fn glob_delegation_suffixes(
&mut self,
trait_def_id: DefId,
impl_def_id: LocalDefId,
) -> Result<Vec<(Ident, Option<Ident>)>, Indeterminate>;
}
pub trait LintStoreExpand {

12
compiler/rustc_expand/src/errors.rs
View file

@ -435,8 +435,16 @@ pub struct ExpectedParenOrBrace<'a> {
}
#[derive(Diagnostic)]
#[diag(expand_empty_delegation_list)]
pub(crate) struct EmptyDelegationList {
#[diag(expand_empty_delegation_mac)]
pub(crate) struct EmptyDelegationMac {
#[primary_span]
pub span: Span,
pub kind: String,
}
#[derive(Diagnostic)]
#[diag(expand_glob_delegation_outside_impls)]
pub(crate) struct GlobDelegationOutsideImpls {
#[primary_span]
pub span: Span,
}

152
compiler/rustc_expand/src/expand.rs
View file

@ -1,8 +1,8 @@
use crate::base::*;
use crate::config::StripUnconfigured;
use crate::errors::{
EmptyDelegationList, IncompleteParse, RecursionLimitReached, RemoveExprNotSupported,
RemoveNodeNotSupported, UnsupportedKeyValue, WrongFragmentKind,
EmptyDelegationMac, GlobDelegationOutsideImpls, IncompleteParse, RecursionLimitReached,
RemoveExprNotSupported, RemoveNodeNotSupported, UnsupportedKeyValue, WrongFragmentKind,
};
use crate::mbe::diagnostics::annotate_err_with_kind;
use crate::module::{mod_dir_path, parse_external_mod, DirOwnership, ParsedExternalMod};
@ -343,6 +343,9 @@ pub enum InvocationKind {
is_const: bool,
item: Annotatable,
},
GlobDelegation {
item: P<ast::AssocItem>,
},
}
impl InvocationKind {
@ -370,6 +373,7 @@ impl Invocation {
InvocationKind::Bang { span, .. } => *span,
InvocationKind::Attr { attr, .. } => attr.span,
InvocationKind::Derive { path, .. } => path.span,
InvocationKind::GlobDelegation { item } => item.span,
}
}
@ -378,6 +382,7 @@ impl Invocation {
InvocationKind::Bang { span, .. } => span,
InvocationKind::Attr { attr, .. } => &mut attr.span,
InvocationKind::Derive { path, .. } => &mut path.span,
InvocationKind::GlobDelegation { item } => &mut item.span,
}
}
}
@ -800,6 +805,36 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
}
_ => unreachable!(),
},
InvocationKind::GlobDelegation { item } => {
let AssocItemKind::DelegationMac(deleg) = &item.kind else { unreachable!() };
let suffixes = match ext {
SyntaxExtensionKind::GlobDelegation(expander) => match expander.expand(self.cx)
{
ExpandResult::Ready(suffixes) => suffixes,
ExpandResult::Retry(()) => {
// Reassemble the original invocation for retrying.
return ExpandResult::Retry(Invocation {
kind: InvocationKind::GlobDelegation { item },
..invoc
});
}
},
SyntaxExtensionKind::LegacyBang(..) => {
let msg = "expanded a dummy glob delegation";
let guar = self.cx.dcx().span_delayed_bug(span, msg);
return ExpandResult::Ready(fragment_kind.dummy(span, guar));
}
_ => unreachable!(),
};
type Node = AstNodeWrapper<P<ast::AssocItem>, ImplItemTag>;
let single_delegations = build_single_delegations::<Node>(
self.cx, deleg, &item, &suffixes, item.span, true,
);
fragment_kind.expect_from_annotatables(
single_delegations.map(|item| Annotatable::ImplItem(P(item))),
)
}
})
}
@ -1067,7 +1102,7 @@ trait InvocationCollectorNode: HasAttrs + HasNodeId + Sized {
fn take_mac_call(self) -> (P<ast::MacCall>, Self::AttrsTy, AddSemicolon) {
unreachable!()
}
fn delegation_list(&self) -> Option<(&ast::DelegationMac, &ast::Item<Self::ItemKind>)> {
fn delegation(&self) -> Option<(&ast::DelegationMac, &ast::Item<Self::ItemKind>)> {
None
}
fn delegation_item_kind(_deleg: Box<ast::Delegation>) -> Self::ItemKind {
@ -1126,7 +1161,7 @@ impl InvocationCollectorNode for P<ast::Item> {
_ => unreachable!(),
}
}
fn delegation_list(&self) -> Option<(&ast::DelegationMac, &ast::Item<Self::ItemKind>)> {
fn delegation(&self) -> Option<(&ast::DelegationMac, &ast::Item<Self::ItemKind>)> {
match &self.kind {
ItemKind::DelegationMac(deleg) => Some((deleg, self)),
_ => None,
@ -1270,7 +1305,7 @@ impl InvocationCollectorNode for AstNodeWrapper<P<ast::AssocItem>, TraitItemTag>
_ => unreachable!(),
}
}
fn delegation_list(&self) -> Option<(&ast::DelegationMac, &ast::Item<Self::ItemKind>)> {
fn delegation(&self) -> Option<(&ast::DelegationMac, &ast::Item<Self::ItemKind>)> {
match &self.wrapped.kind {
AssocItemKind::DelegationMac(deleg) => Some((deleg, &self.wrapped)),
_ => None,
@ -1311,7 +1346,7 @@ impl InvocationCollectorNode for AstNodeWrapper<P<ast::AssocItem>, ImplItemTag>
_ => unreachable!(),
}
}
fn delegation_list(&self) -> Option<(&ast::DelegationMac, &ast::Item<Self::ItemKind>)> {
fn delegation(&self) -> Option<(&ast::DelegationMac, &ast::Item<Self::ItemKind>)> {
match &self.wrapped.kind {
AssocItemKind::DelegationMac(deleg) => Some((deleg, &self.wrapped)),
_ => None,
@ -1487,7 +1522,7 @@ impl InvocationCollectorNode for ast::Stmt {
};
(mac, attrs, if add_semicolon { AddSemicolon::Yes } else { AddSemicolon::No })
}
fn delegation_list(&self) -> Option<(&ast::DelegationMac, &ast::Item<Self::ItemKind>)> {
fn delegation(&self) -> Option<(&ast::DelegationMac, &ast::Item<Self::ItemKind>)> {
match &self.kind {
StmtKind::Item(item) => match &item.kind {
ItemKind::DelegationMac(deleg) => Some((deleg, item)),
@ -1684,6 +1719,44 @@ impl InvocationCollectorNode for AstNodeWrapper<P<ast::Expr>, MethodReceiverTag>
}
}
fn build_single_delegations<'a, Node: InvocationCollectorNode>(
ecx: &ExtCtxt<'_>,
deleg: &'a ast::DelegationMac,
item: &'a ast::Item<Node::ItemKind>,
suffixes: &'a [(Ident, Option<Ident>)],
item_span: Span,
from_glob: bool,
) -> impl Iterator<Item = ast::Item<Node::ItemKind>> + 'a {
if suffixes.is_empty() {
// Report an error for now, to avoid keeping stem for resolution and
// stability checks.
let kind = String::from(if from_glob { "glob" } else { "list" });
ecx.dcx().emit_err(EmptyDelegationMac { span: item.span, kind });
}
suffixes.iter().map(move |&(ident, rename)| {
let mut path = deleg.prefix.clone();
path.segments.push(ast::PathSegment { ident, id: ast::DUMMY_NODE_ID, args: None });
ast::Item {
attrs: item.attrs.clone(),
id: ast::DUMMY_NODE_ID,
span: if from_glob { item_span } else { ident.span },
vis: item.vis.clone(),
ident: rename.unwrap_or(ident),
kind: Node::delegation_item_kind(Box::new(ast::Delegation {
id: ast::DUMMY_NODE_ID,
qself: deleg.qself.clone(),
path,
rename,
body: deleg.body.clone(),
from_glob,
})),
tokens: None,
}
})
}
struct InvocationCollector<'a, 'b> {
cx: &'a mut ExtCtxt<'b>,
invocations: Vec<(Invocation, Option<Lrc<SyntaxExtension>>)>,
@ -1702,6 +1775,11 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
fn collect(&mut self, fragment_kind: AstFragmentKind, kind: InvocationKind) -> AstFragment {
let expn_id = LocalExpnId::fresh_empty();
if matches!(kind, InvocationKind::GlobDelegation { .. }) {
// In resolver we need to know which invocation ids are delegations early,
// before their `ExpnData` is filled.
self.cx.resolver.register_glob_delegation(expn_id);
}
let vis = kind.placeholder_visibility();
self.invocations.push((
Invocation {
@ -1734,6 +1812,14 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
self.collect(kind, InvocationKind::Attr { attr, pos, item, derives })
}
fn collect_glob_delegation(
&mut self,
item: P<ast::AssocItem>,
kind: AstFragmentKind,
) -> AstFragment {
self.collect(kind, InvocationKind::GlobDelegation { item })
}
/// If `item` is an attribute invocation, remove the attribute and return it together with
/// its position and derives following it. We have to collect the derives in order to resolve
/// legacy derive helpers (helpers written before derives that introduce them).
@ -1901,37 +1987,27 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
Node::post_flat_map_node_collect_bang(&mut res, add_semicolon);
res
}
None if let Some((deleg, item)) = node.delegation_list() => {
if deleg.suffixes.is_empty() {
// Report an error for now, to avoid keeping stem for resolution and
// stability checks.
self.cx.dcx().emit_err(EmptyDelegationList { span: item.span });
}
Node::flatten_outputs(deleg.suffixes.iter().map(|&(ident, rename)| {
let mut path = deleg.prefix.clone();
path.segments.push(ast::PathSegment {
ident,
id: ast::DUMMY_NODE_ID,
args: None,
});
let mut item = Node::from_item(ast::Item {
attrs: item.attrs.clone(),
id: ast::DUMMY_NODE_ID,
span: ident.span,
vis: item.vis.clone(),
ident: rename.unwrap_or(ident),
kind: Node::delegation_item_kind(Box::new(ast::Delegation {
id: ast::DUMMY_NODE_ID,
qself: deleg.qself.clone(),
path,
rename,
body: deleg.body.clone(),
})),
tokens: None,
});
None if let Some((deleg, item)) = node.delegation() => {
let Some(suffixes) = &deleg.suffixes else {
let item = match node.to_annotatable() {
Annotatable::ImplItem(item) => item,
ann @ (Annotatable::Item(_)
| Annotatable::TraitItem(_)
| Annotatable::Stmt(_)) => {
let span = ann.span();
self.cx.dcx().emit_err(GlobDelegationOutsideImpls { span });
return Default::default();
}
_ => unreachable!(),
};
return self.collect_glob_delegation(item, Node::KIND).make_ast::<Node>();
};
let single_delegations = build_single_delegations::<Node>(
self.cx, deleg, item, suffixes, item.span, false,
);
Node::flatten_outputs(single_delegations.map(|item| {
let mut item = Node::from_item(item);
assign_id!(self, item.node_id_mut(), || item.noop_flat_map(self))
}))
}
@ -1983,7 +2059,7 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
self.collect_bang(mac, Node::KIND).make_ast::<Node>()
})
}
None if node.delegation_list().is_some() => unreachable!(),
None if node.delegation().is_some() => unreachable!(),
None => {
assign_id!(self, node.node_id_mut(), || node.noop_visit(self))
}