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Unrolled build for rust-lang#124135
Rollup merge of rust-lang#124135 - petrochenkov:deleglob, r=fmease 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 rust-lang/rfcs#3530 (comment), but unlike with list delegation in rust-lang#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 rust-lang#118212.
2 parents 4e63822 + 22d0b1e commit 926b765

29 files changed

+878
-123
lines changed

‎compiler/rustc_ast/src/ast.rs

+6-3
Original file line numberDiff line numberDiff line change
@@ -3161,13 +3161,16 @@ pub struct Delegation {
31613161
pub path: Path,
31623162
pub rename: Option<Ident>,
31633163
pub body: Option<P<Block>>,
3164+
/// The item was expanded from a glob delegation item.
3165+
pub from_glob: bool,
31643166
}
31653167

31663168
#[derive(Clone, Encodable, Decodable, Debug)]
31673169
pub struct DelegationMac {
31683170
pub qself: Option<P<QSelf>>,
31693171
pub prefix: Path,
3170-
pub suffixes: ThinVec<(Ident, Option<Ident>)>,
3172+
// Some for list delegation, and None for glob delegation.
3173+
pub suffixes: Option<ThinVec<(Ident, Option<Ident>)>>,
31713174
pub body: Option<P<Block>>,
31723175
}
31733176

@@ -3294,7 +3297,7 @@ pub enum ItemKind {
32943297
///
32953298
/// E.g. `reuse <Type as Trait>::name { target_expr_template }`.
32963299
Delegation(Box<Delegation>),
3297-
/// A list delegation item (`reuse prefix::{a, b, c}`).
3300+
/// A list or glob delegation item (`reuse prefix::{a, b, c}`, `reuse prefix::*`).
32983301
/// Treated similarly to a macro call and expanded early.
32993302
DelegationMac(Box<DelegationMac>),
33003303
}
@@ -3375,7 +3378,7 @@ pub enum AssocItemKind {
33753378
MacCall(P<MacCall>),
33763379
/// An associated delegation item.
33773380
Delegation(Box<Delegation>),
3378-
/// An associated delegation item list.
3381+
/// An associated list or glob delegation item.
33793382
DelegationMac(Box<DelegationMac>),
33803383
}
33813384

‎compiler/rustc_ast/src/mut_visit.rs

+28-10
Original file line numberDiff line numberDiff line change
@@ -1162,7 +1162,14 @@ impl NoopVisitItemKind for ItemKind {
11621162
}
11631163
ItemKind::MacCall(m) => vis.visit_mac_call(m),
11641164
ItemKind::MacroDef(def) => vis.visit_macro_def(def),
1165-
ItemKind::Delegation(box Delegation { id, qself, path, rename, body }) => {
1165+
ItemKind::Delegation(box Delegation {
1166+
id,
1167+
qself,
1168+
path,
1169+
rename,
1170+
body,
1171+
from_glob: _,
1172+
}) => {
11661173
vis.visit_id(id);
11671174
vis.visit_qself(qself);
11681175
vis.visit_path(path);
@@ -1176,10 +1183,12 @@ impl NoopVisitItemKind for ItemKind {
11761183
ItemKind::DelegationMac(box DelegationMac { qself, prefix, suffixes, body }) => {
11771184
vis.visit_qself(qself);
11781185
vis.visit_path(prefix);
1179-
for (ident, rename) in suffixes {
1180-
vis.visit_ident(ident);
1181-
if let Some(rename) = rename {
1182-
vis.visit_ident(rename);
1186+
if let Some(suffixes) = suffixes {
1187+
for (ident, rename) in suffixes {
1188+
vis.visit_ident(ident);
1189+
if let Some(rename) = rename {
1190+
vis.visit_ident(rename);
1191+
}
11831192
}
11841193
}
11851194
if let Some(body) = body {
@@ -1218,7 +1227,14 @@ impl NoopVisitItemKind for AssocItemKind {
12181227
visit_opt(ty, |ty| visitor.visit_ty(ty));
12191228
}
12201229
AssocItemKind::MacCall(mac) => visitor.visit_mac_call(mac),
1221-
AssocItemKind::Delegation(box Delegation { id, qself, path, rename, body }) => {
1230+
AssocItemKind::Delegation(box Delegation {
1231+
id,
1232+
qself,
1233+
path,
1234+
rename,
1235+
body,
1236+
from_glob: _,
1237+
}) => {
12221238
visitor.visit_id(id);
12231239
visitor.visit_qself(qself);
12241240
visitor.visit_path(path);
@@ -1232,10 +1248,12 @@ impl NoopVisitItemKind for AssocItemKind {
12321248
AssocItemKind::DelegationMac(box DelegationMac { qself, prefix, suffixes, body }) => {
12331249
visitor.visit_qself(qself);
12341250
visitor.visit_path(prefix);
1235-
for (ident, rename) in suffixes {
1236-
visitor.visit_ident(ident);
1237-
if let Some(rename) = rename {
1238-
visitor.visit_ident(rename);
1251+
if let Some(suffixes) = suffixes {
1252+
for (ident, rename) in suffixes {
1253+
visitor.visit_ident(ident);
1254+
if let Some(rename) = rename {
1255+
visitor.visit_ident(rename);
1256+
}
12391257
}
12401258
}
12411259
if let Some(body) = body {

‎compiler/rustc_ast/src/visit.rs

+28-10
Original file line numberDiff line numberDiff line change
@@ -408,7 +408,14 @@ impl WalkItemKind for ItemKind {
408408
}
409409
ItemKind::MacCall(mac) => try_visit!(visitor.visit_mac_call(mac)),
410410
ItemKind::MacroDef(ts) => try_visit!(visitor.visit_mac_def(ts, item.id)),
411-
ItemKind::Delegation(box Delegation { id, qself, path, rename, body }) => {
411+
ItemKind::Delegation(box Delegation {
412+
id,
413+
qself,
414+
path,
415+
rename,
416+
body,
417+
from_glob: _,
418+
}) => {
412419
if let Some(qself) = qself {
413420
try_visit!(visitor.visit_ty(&qself.ty));
414421
}
@@ -421,10 +428,12 @@ impl WalkItemKind for ItemKind {
421428
try_visit!(visitor.visit_ty(&qself.ty));
422429
}
423430
try_visit!(visitor.visit_path(prefix, item.id));
424-
for (ident, rename) in suffixes {
425-
visitor.visit_ident(*ident);
426-
if let Some(rename) = rename {
427-
visitor.visit_ident(*rename);
431+
if let Some(suffixes) = suffixes {
432+
for (ident, rename) in suffixes {
433+
visitor.visit_ident(*ident);
434+
if let Some(rename) = rename {
435+
visitor.visit_ident(*rename);
436+
}
428437
}
429438
}
430439
visit_opt!(visitor, visit_block, body);
@@ -837,7 +846,14 @@ impl WalkItemKind for AssocItemKind {
837846
AssocItemKind::MacCall(mac) => {
838847
try_visit!(visitor.visit_mac_call(mac));
839848
}
840-
AssocItemKind::Delegation(box Delegation { id, qself, path, rename, body }) => {
849+
AssocItemKind::Delegation(box Delegation {
850+
id,
851+
qself,
852+
path,
853+
rename,
854+
body,
855+
from_glob: _,
856+
}) => {
841857
if let Some(qself) = qself {
842858
try_visit!(visitor.visit_ty(&qself.ty));
843859
}
@@ -850,10 +866,12 @@ impl WalkItemKind for AssocItemKind {
850866
try_visit!(visitor.visit_ty(&qself.ty));
851867
}
852868
try_visit!(visitor.visit_path(prefix, item.id));
853-
for (ident, rename) in suffixes {
854-
visitor.visit_ident(*ident);
855-
if let Some(rename) = rename {
856-
visitor.visit_ident(*rename);
869+
if let Some(suffixes) = suffixes {
870+
for (ident, rename) in suffixes {
871+
visitor.visit_ident(*ident);
872+
if let Some(rename) = rename {
873+
visitor.visit_ident(*rename);
874+
}
857875
}
858876
}
859877
visit_opt!(visitor, visit_block, body);

‎compiler/rustc_ast_pretty/src/pprust/state/item.rs

+32-19
Original file line numberDiff line numberDiff line change
@@ -9,6 +9,12 @@ use rustc_ast::ptr::P;
99
use rustc_ast::ModKind;
1010
use rustc_span::symbol::Ident;
1111

12+
enum DelegationKind<'a> {
13+
Single,
14+
List(&'a [(Ident, Option<Ident>)]),
15+
Glob,
16+
}
17+
1218
fn visibility_qualified(vis: &ast::Visibility, s: &str) -> String {
1319
format!("{}{}", State::to_string(|s| s.print_visibility(vis)), s)
1420
}
@@ -387,15 +393,15 @@ impl<'a> State<'a> {
387393
&item.vis,
388394
&deleg.qself,
389395
&deleg.path,
390-
None,
396+
DelegationKind::Single,
391397
&deleg.body,
392398
),
393399
ast::ItemKind::DelegationMac(deleg) => self.print_delegation(
394400
&item.attrs,
395401
&item.vis,
396402
&deleg.qself,
397403
&deleg.prefix,
398-
Some(&deleg.suffixes),
404+
deleg.suffixes.as_ref().map_or(DelegationKind::Glob, |s| DelegationKind::List(s)),
399405
&deleg.body,
400406
),
401407
}
@@ -579,28 +585,28 @@ impl<'a> State<'a> {
579585
vis,
580586
&deleg.qself,
581587
&deleg.path,
582-
None,
588+
DelegationKind::Single,
583589
&deleg.body,
584590
),
585591
ast::AssocItemKind::DelegationMac(deleg) => self.print_delegation(
586592
&item.attrs,
587593
vis,
588594
&deleg.qself,
589595
&deleg.prefix,
590-
Some(&deleg.suffixes),
596+
deleg.suffixes.as_ref().map_or(DelegationKind::Glob, |s| DelegationKind::List(s)),
591597
&deleg.body,
592598
),
593599
}
594600
self.ann.post(self, AnnNode::SubItem(id))
595601
}
596602

597-
pub(crate) fn print_delegation(
603+
fn print_delegation(
598604
&mut self,
599605
attrs: &[ast::Attribute],
600606
vis: &ast::Visibility,
601607
qself: &Option<P<ast::QSelf>>,
602608
path: &ast::Path,
603-
suffixes: Option<&[(Ident, Option<Ident>)]>,
609+
kind: DelegationKind<'_>,
604610
body: &Option<P<ast::Block>>,
605611
) {
606612
if body.is_some() {
@@ -614,21 +620,28 @@ impl<'a> State<'a> {
614620
} else {
615621
self.print_path(path, false, 0);
616622
}
617-
if let Some(suffixes) = suffixes {
618-
self.word("::");
619-
self.word("{");
620-
for (i, (ident, rename)) in suffixes.iter().enumerate() {
621-
self.print_ident(*ident);
622-
if let Some(rename) = rename {
623-
self.nbsp();
624-
self.word_nbsp("as");
625-
self.print_ident(*rename);
626-
}
627-
if i != suffixes.len() - 1 {
628-
self.word_space(",");
623+
match kind {
624+
DelegationKind::Single => {}
625+
DelegationKind::List(suffixes) => {
626+
self.word("::");
627+
self.word("{");
628+
for (i, (ident, rename)) in suffixes.iter().enumerate() {
629+
self.print_ident(*ident);
630+
if let Some(rename) = rename {
631+
self.nbsp();
632+
self.word_nbsp("as");
633+
self.print_ident(*rename);
634+
}
635+
if i != suffixes.len() - 1 {
636+
self.word_space(",");
637+
}
629638
}
639+
self.word("}");
640+
}
641+
DelegationKind::Glob => {
642+
self.word("::");
643+
self.word("*");
630644
}
631-
self.word("}");
632645
}
633646
if let Some(body) = body {
634647
self.nbsp();

‎compiler/rustc_expand/messages.ftl

+5-2
Original file line numberDiff line numberDiff line change
@@ -35,8 +35,8 @@ expand_duplicate_matcher_binding = duplicate matcher binding
3535
.label = duplicate binding
3636
.label2 = previous binding
3737
38-
expand_empty_delegation_list =
39-
empty list delegation is not supported
38+
expand_empty_delegation_mac =
39+
empty {$kind} delegation is not supported
4040
4141
expand_expected_paren_or_brace =
4242
expected `(` or `{"{"}`, found `{$token}`
@@ -58,6 +58,9 @@ expand_feature_removed =
5858
.label = feature has been removed
5959
.reason = {$reason}
6060
61+
expand_glob_delegation_outside_impls =
62+
glob delegation is only supported in impls
63+
6164
expand_helper_attribute_name_invalid =
6265
`{$name}` cannot be a name of derive helper attribute
6366

‎compiler/rustc_expand/src/base.rs

+46-1
Original file line numberDiff line numberDiff line change
@@ -357,6 +357,10 @@ where
357357
}
358358
}
359359

360+
pub trait GlobDelegationExpander {
361+
fn expand(&self, ecx: &mut ExtCtxt<'_>) -> ExpandResult<Vec<(Ident, Option<Ident>)>, ()>;
362+
}
363+
360364
// Use a macro because forwarding to a simple function has type system issues
361365
macro_rules! make_stmts_default {
362366
($me:expr) => {
@@ -714,6 +718,9 @@ pub enum SyntaxExtensionKind {
714718
/// The produced AST fragment is appended to the input AST fragment.
715719
Box<dyn MultiItemModifier + sync::DynSync + sync::DynSend>,
716720
),
721+
722+
/// A glob delegation.
723+
GlobDelegation(Box<dyn GlobDelegationExpander + sync::DynSync + sync::DynSend>),
717724
}
718725

719726
/// A struct representing a macro definition in "lowered" form ready for expansion.
@@ -748,7 +755,9 @@ impl SyntaxExtension {
748755
/// Returns which kind of macro calls this syntax extension.
749756
pub fn macro_kind(&self) -> MacroKind {
750757
match self.kind {
751-
SyntaxExtensionKind::Bang(..) | SyntaxExtensionKind::LegacyBang(..) => MacroKind::Bang,
758+
SyntaxExtensionKind::Bang(..)
759+
| SyntaxExtensionKind::LegacyBang(..)
760+
| SyntaxExtensionKind::GlobDelegation(..) => MacroKind::Bang,
752761
SyntaxExtensionKind::Attr(..)
753762
| SyntaxExtensionKind::LegacyAttr(..)
754763
| SyntaxExtensionKind::NonMacroAttr => MacroKind::Attr,
@@ -922,6 +931,32 @@ impl SyntaxExtension {
922931
SyntaxExtension::default(SyntaxExtensionKind::NonMacroAttr, edition)
923932
}
924933

934+
pub fn glob_delegation(
935+
trait_def_id: DefId,
936+
impl_def_id: LocalDefId,
937+
edition: Edition,
938+
) -> SyntaxExtension {
939+
struct GlobDelegationExpanderImpl {
940+
trait_def_id: DefId,
941+
impl_def_id: LocalDefId,
942+
}
943+
impl GlobDelegationExpander for GlobDelegationExpanderImpl {
944+
fn expand(
945+
&self,
946+
ecx: &mut ExtCtxt<'_>,
947+
) -> ExpandResult<Vec<(Ident, Option<Ident>)>, ()> {
948+
match ecx.resolver.glob_delegation_suffixes(self.trait_def_id, self.impl_def_id) {
949+
Ok(suffixes) => ExpandResult::Ready(suffixes),
950+
Err(Indeterminate) if ecx.force_mode => ExpandResult::Ready(Vec::new()),
951+
Err(Indeterminate) => ExpandResult::Retry(()),
952+
}
953+
}
954+
}
955+
956+
let expander = GlobDelegationExpanderImpl { trait_def_id, impl_def_id };
957+
SyntaxExtension::default(SyntaxExtensionKind::GlobDelegation(Box::new(expander)), edition)
958+
}
959+
925960
pub fn expn_data(
926961
&self,
927962
parent: LocalExpnId,
@@ -1030,6 +1065,16 @@ pub trait ResolverExpand {
10301065

10311066
/// Tools registered with `#![register_tool]` and used by tool attributes and lints.
10321067
fn registered_tools(&self) -> &RegisteredTools;
1068+
1069+
/// Mark this invocation id as a glob delegation.
1070+
fn register_glob_delegation(&mut self, invoc_id: LocalExpnId);
1071+
1072+
/// Names of specific methods to which glob delegation expands.
1073+
fn glob_delegation_suffixes(
1074+
&mut self,
1075+
trait_def_id: DefId,
1076+
impl_def_id: LocalDefId,
1077+
) -> Result<Vec<(Ident, Option<Ident>)>, Indeterminate>;
10331078
}
10341079

10351080
pub trait LintStoreExpand {

‎compiler/rustc_expand/src/errors.rs

+10-2
Original file line numberDiff line numberDiff line change
@@ -435,8 +435,16 @@ pub struct ExpectedParenOrBrace<'a> {
435435
}
436436

437437
#[derive(Diagnostic)]
438-
#[diag(expand_empty_delegation_list)]
439-
pub(crate) struct EmptyDelegationList {
438+
#[diag(expand_empty_delegation_mac)]
439+
pub(crate) struct EmptyDelegationMac {
440+
#[primary_span]
441+
pub span: Span,
442+
pub kind: String,
443+
}
444+
445+
#[derive(Diagnostic)]
446+
#[diag(expand_glob_delegation_outside_impls)]
447+
pub(crate) struct GlobDelegationOutsideImpls {
440448
#[primary_span]
441449
pub span: Span,
442450
}

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