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eholkeholk
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Plumb awaitness of for loops
1 parent bf9229a commit 27d6539

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26 files changed

+137
-53
lines changed

26 files changed

+137
-53
lines changed

‎compiler/rustc_ast/src/ast.rs

Lines changed: 10 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1274,7 +1274,7 @@ impl Expr {
12741274
ExprKind::Let(..) => ExprPrecedence::Let,
12751275
ExprKind::If(..) => ExprPrecedence::If,
12761276
ExprKind::While(..) => ExprPrecedence::While,
1277-
ExprKind::ForLoop(..) => ExprPrecedence::ForLoop,
1277+
ExprKind::ForLoop { .. } => ExprPrecedence::ForLoop,
12781278
ExprKind::Loop(..) => ExprPrecedence::Loop,
12791279
ExprKind::Match(..) => ExprPrecedence::Match,
12801280
ExprKind::Closure(..) => ExprPrecedence::Closure,
@@ -1436,10 +1436,10 @@ pub enum ExprKind {
14361436
While(P<Expr>, P<Block>, Option<Label>),
14371437
/// A `for` loop, with an optional label.
14381438
///
1439-
/// `'label: for pat in expr { block }`
1439+
/// `'label: for await? pat in iter { block }`
14401440
///
14411441
/// This is desugared to a combination of `loop` and `match` expressions.
1442-
ForLoop(P<Pat>, P<Expr>, P<Block>, Option<Label>),
1442+
ForLoop { pat: P<Pat>, iter: P<Expr>, body: P<Block>, label: Option<Label>, kind: ForLoopKind },
14431443
/// Conditionless loop (can be exited with `break`, `continue`, or `return`).
14441444
///
14451445
/// `'label: loop { block }`
@@ -1542,6 +1542,13 @@ pub enum ExprKind {
15421542
Err,
15431543
}
15441544

1545+
/// Used to differentiate between `for` loops and `for await` loops.
1546+
#[derive(Clone, Copy, Encodable, Decodable, Debug, PartialEq, Eq)]
1547+
pub enum ForLoopKind {
1548+
For,
1549+
ForAwait,
1550+
}
1551+
15451552
/// Used to differentiate between `async {}` blocks and `gen {}` blocks.
15461553
#[derive(Clone, Encodable, Decodable, Debug, PartialEq, Eq)]
15471554
pub enum GenBlockKind {

‎compiler/rustc_ast/src/mut_visit.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1389,7 +1389,7 @@ pub fn noop_visit_expr<T: MutVisitor>(
13891389
vis.visit_block(body);
13901390
visit_opt(label, |label| vis.visit_label(label));
13911391
}
1392-
ExprKind::ForLoop(pat, iter, body, label) => {
1392+
ExprKind::ForLoop { pat, iter, body, label, kind: _ } => {
13931393
vis.visit_pat(pat);
13941394
vis.visit_expr(iter);
13951395
vis.visit_block(body);

‎compiler/rustc_ast/src/util/classify.rs

Lines changed: 11 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -19,7 +19,7 @@ pub fn expr_requires_semi_to_be_stmt(e: &ast::Expr) -> bool {
1919
| ast::ExprKind::Block(..)
2020
| ast::ExprKind::While(..)
2121
| ast::ExprKind::Loop(..)
22-
| ast::ExprKind::ForLoop(..)
22+
| ast::ExprKind::ForLoop { .. }
2323
| ast::ExprKind::TryBlock(..)
2424
| ast::ExprKind::ConstBlock(..)
2525
)
@@ -48,8 +48,16 @@ pub fn expr_trailing_brace(mut expr: &ast::Expr) -> Option<&ast::Expr> {
4848
Closure(closure) => {
4949
expr = &closure.body;
5050
}
51-
Gen(..) | Block(..) | ForLoop(..) | If(..) | Loop(..) | Match(..) | Struct(..)
52-
| TryBlock(..) | While(..) | ConstBlock(_) => break Some(expr),
51+
Gen(..)
52+
| Block(..)
53+
| ForLoop { .. }
54+
| If(..)
55+
| Loop(..)
56+
| Match(..)
57+
| Struct(..)
58+
| TryBlock(..)
59+
| While(..)
60+
| ConstBlock(_) => break Some(expr),
5361

5462
// FIXME: These can end in `}`, but changing these would break stable code.
5563
InlineAsm(_) | OffsetOf(_, _) | MacCall(_) | IncludedBytes(_) | FormatArgs(_) => {

‎compiler/rustc_ast/src/visit.rs

Lines changed: 5 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -844,11 +844,11 @@ pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) {
844844
visitor.visit_expr(subexpression);
845845
visitor.visit_block(block);
846846
}
847-
ExprKind::ForLoop(pattern, subexpression, block, opt_label) => {
848-
walk_list!(visitor, visit_label, opt_label);
849-
visitor.visit_pat(pattern);
850-
visitor.visit_expr(subexpression);
851-
visitor.visit_block(block);
847+
ExprKind::ForLoop { pat, iter, body, label, kind: _ } => {
848+
walk_list!(visitor, visit_label, label);
849+
visitor.visit_pat(pat);
850+
visitor.visit_expr(iter);
851+
visitor.visit_block(body);
852852
}
853853
ExprKind::Loop(block, opt_label, _) => {
854854
walk_list!(visitor, visit_label, opt_label);

‎compiler/rustc_ast_lowering/src/expr.rs

Lines changed: 5 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -56,12 +56,12 @@ impl<'hir> LoweringContext<'_, 'hir> {
5656
return ex;
5757
}
5858
// Desugar `ExprForLoop`
59-
// from: `[opt_ident]: for <pat> in <head> <body>`
59+
// from: `[opt_ident]: for await? <pat> in <iter> <body>`
6060
//
6161
// This also needs special handling because the HirId of the returned `hir::Expr` will not
6262
// correspond to the `e.id`, so `lower_expr_for` handles attribute lowering itself.
63-
ExprKind::ForLoop(pat, head, body, opt_label) => {
64-
return self.lower_expr_for(e, pat, head, body, *opt_label);
63+
ExprKind::ForLoop { pat, iter, body, label, kind } => {
64+
return self.lower_expr_for(e, pat, iter, body, *label, *kind);
6565
}
6666
_ => (),
6767
}
@@ -337,7 +337,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
337337
),
338338
ExprKind::Try(sub_expr) => self.lower_expr_try(e.span, sub_expr),
339339

340-
ExprKind::Paren(_) | ExprKind::ForLoop(..) => {
340+
ExprKind::Paren(_) | ExprKind::ForLoop{..} => {
341341
unreachable!("already handled")
342342
}
343343

@@ -1673,6 +1673,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
16731673
head: &Expr,
16741674
body: &Block,
16751675
opt_label: Option<Label>,
1676+
_loop_kind: ForLoopKind,
16761677
) -> hir::Expr<'hir> {
16771678
let head = self.lower_expr_mut(head);
16781679
let pat = self.lower_pat(pat);

‎compiler/rustc_ast_passes/src/feature_gate.rs

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -526,6 +526,7 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
526526
"async closures are unstable",
527527
"to use an async block, remove the `||`: `async {`"
528528
);
529+
gate_all!(async_for_loop, "`for await` loops are experimental");
529530
gate_all!(
530531
closure_lifetime_binder,
531532
"`for<...>` binders for closures are experimental",

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

Lines changed: 7 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,6 @@
11
use crate::pp::Breaks::Inconsistent;
22
use crate::pprust::state::{AnnNode, PrintState, State, INDENT_UNIT};
3+
use ast::ForLoopKind;
34
use itertools::{Itertools, Position};
45
use rustc_ast::ptr::P;
56
use rustc_ast::token;
@@ -418,20 +419,23 @@ impl<'a> State<'a> {
418419
self.space();
419420
self.print_block_with_attrs(blk, attrs);
420421
}
421-
ast::ExprKind::ForLoop(pat, iter, blk, opt_label) => {
422-
if let Some(label) = opt_label {
422+
ast::ExprKind::ForLoop { pat, iter, body, label, kind } => {
423+
if let Some(label) = label {
423424
self.print_ident(label.ident);
424425
self.word_space(":");
425426
}
426427
self.cbox(0);
427428
self.ibox(0);
428429
self.word_nbsp("for");
430+
if kind == &ForLoopKind::ForAwait {
431+
self.word_nbsp("await");
432+
}
429433
self.print_pat(pat);
430434
self.space();
431435
self.word_space("in");
432436
self.print_expr_as_cond(iter);
433437
self.space();
434-
self.print_block_with_attrs(blk, attrs);
438+
self.print_block_with_attrs(body, attrs);
435439
}
436440
ast::ExprKind::Loop(blk, opt_label, _) => {
437441
if let Some(label) = opt_label {

‎compiler/rustc_builtin_macros/src/assert/context.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -303,7 +303,7 @@ impl<'cx, 'a> Context<'cx, 'a> {
303303
| ExprKind::Continue(_)
304304
| ExprKind::Err
305305
| ExprKind::Field(_, _)
306-
| ExprKind::ForLoop(_, _, _, _)
306+
| ExprKind::ForLoop {..}
307307
| ExprKind::FormatArgs(_)
308308
| ExprKind::IncludedBytes(..)
309309
| ExprKind::InlineAsm(_)

‎compiler/rustc_feature/src/unstable.rs

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -357,6 +357,8 @@ declare_features! (
357357
(unstable, async_closure, "1.37.0", Some(62290)),
358358
/// Allows `#[track_caller]` on async functions.
359359
(unstable, async_fn_track_caller, "1.73.0", Some(110011)),
360+
/// Allows `for await` loops.
361+
(unstable, async_for_loop, "CURRENT_RUSTC_VERSION", None),
360362
/// Allows builtin # foo() syntax
361363
(unstable, builtin_syntax, "1.71.0", Some(110680)),
362364
/// Treat `extern "C"` function as nounwind.

‎compiler/rustc_lint/src/unused.rs

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -852,8 +852,8 @@ trait UnusedDelimLint {
852852
(cond, UnusedDelimsCtx::WhileCond, true, Some(left), Some(right), true)
853853
}
854854

855-
ForLoop(_, ref cond, ref block, ..) => {
856-
(cond, UnusedDelimsCtx::ForIterExpr, true, None, Some(block.span.lo()), true)
855+
ForLoop { ref iter, ref body, .. } => {
856+
(iter, UnusedDelimsCtx::ForIterExpr, true, None, Some(body.span.lo()), true)
857857
}
858858

859859
Match(ref head, _) if Self::LINT_EXPR_IN_PATTERN_MATCHING_CTX => {
@@ -1085,7 +1085,7 @@ impl EarlyLintPass for UnusedParens {
10851085
}
10861086

10871087
match e.kind {
1088-
ExprKind::Let(ref pat, _, _, _) | ExprKind::ForLoop(ref pat, ..) => {
1088+
ExprKind::Let(ref pat, _, _, _) | ExprKind::ForLoop { ref pat, .. } => {
10891089
self.check_unused_parens_pat(cx, pat, false, false, (true, true));
10901090
}
10911091
// We ignore parens in cases like `if (((let Some(0) = Some(1))))` because we already

‎compiler/rustc_parse/src/parser/expr.rs

Lines changed: 14 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,7 @@ use super::{
1010
use crate::errors;
1111
use crate::maybe_recover_from_interpolated_ty_qpath;
1212
use ast::mut_visit::{noop_visit_expr, MutVisitor};
13-
use ast::{CoroutineKind, GenBlockKind, Pat, Path, PathSegment};
13+
use ast::{CoroutineKind, ForLoopKind, GenBlockKind, Pat, Path, PathSegment};
1414
use core::mem;
1515
use rustc_ast::ptr::P;
1616
use rustc_ast::token::{self, Delimiter, Token, TokenKind};
@@ -1801,7 +1801,7 @@ impl<'a> Parser<'a> {
18011801
&& matches!(
18021802
expr.kind,
18031803
ExprKind::While(_, _, None)
1804-
| ExprKind::ForLoop(_, _, _, None)
1804+
| ExprKind::ForLoop { label: None, .. }
18051805
| ExprKind::Loop(_, None, _)
18061806
| ExprKind::Block(_, None)
18071807
)
@@ -2682,8 +2682,16 @@ impl<'a> Parser<'a> {
26822682
Ok((pat, expr))
26832683
}
26842684

2685-
/// Parses `for <src_pat> in <src_expr> <src_loop_block>` (`for` token already eaten).
2685+
/// Parses `for await? <src_pat> in <src_expr> <src_loop_block>` (`for` token already eaten).
26862686
fn parse_expr_for(&mut self, opt_label: Option<Label>, lo: Span) -> PResult<'a, P<Expr>> {
2687+
let is_await = self.eat_keyword(kw::Await);
2688+
2689+
if is_await {
2690+
self.sess.gated_spans.gate(sym::async_for_loop, self.prev_token.span);
2691+
}
2692+
2693+
let kind = if is_await { ForLoopKind::ForAwait } else { ForLoopKind::For };
2694+
26872695
let (pat, expr) = self.parse_for_head()?;
26882696
// Recover from missing expression in `for` loop
26892697
if matches!(expr.kind, ExprKind::Block(..))
@@ -2696,13 +2704,13 @@ impl<'a> Parser<'a> {
26962704
let block = self.mk_block(thin_vec![], BlockCheckMode::Default, self.prev_token.span);
26972705
return Ok(self.mk_expr(
26982706
lo.to(self.prev_token.span),
2699-
ExprKind::ForLoop(pat, err_expr, block, opt_label),
2707+
ExprKind::ForLoop { pat, iter: err_expr, body: block, label: opt_label, kind },
27002708
));
27012709
}
27022710

27032711
let (attrs, loop_block) = self.parse_inner_attrs_and_block()?;
27042712

2705-
let kind = ExprKind::ForLoop(pat, expr, loop_block, opt_label);
2713+
let kind = ExprKind::ForLoop { pat, iter: expr, body: loop_block, label: opt_label, kind };
27062714

27072715
self.recover_loop_else("for", lo)?;
27082716

@@ -3798,7 +3806,7 @@ impl MutVisitor for CondChecker<'_> {
37983806
| ExprKind::Lit(_)
37993807
| ExprKind::If(_, _, _)
38003808
| ExprKind::While(_, _, _)
3801-
| ExprKind::ForLoop(_, _, _, _)
3809+
| ExprKind::ForLoop { .. }
38023810
| ExprKind::Loop(_, _, _)
38033811
| ExprKind::Match(_, _)
38043812
| ExprKind::Closure(_)

‎compiler/rustc_resolve/src/late.rs

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -4252,11 +4252,11 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
42524252
});
42534253
}
42544254

4255-
ExprKind::ForLoop(ref pat, ref iter_expr, ref block, label) => {
4256-
self.visit_expr(iter_expr);
4255+
ExprKind::ForLoop { ref pat, ref iter, ref body, label, kind: _ } => {
4256+
self.visit_expr(iter);
42574257
self.with_rib(ValueNS, RibKind::Normal, |this| {
42584258
this.resolve_pattern_top(pat, PatternSource::For);
4259-
this.resolve_labeled_block(label, expr.id, block);
4259+
this.resolve_labeled_block(label, expr.id, body);
42604260
});
42614261
}
42624262

‎compiler/rustc_resolve/src/late/diagnostics.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1409,7 +1409,7 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
14091409
| ExprKind::Unary(..)
14101410
| ExprKind::If(..)
14111411
| ExprKind::While(..)
1412-
| ExprKind::ForLoop(..)
1412+
| ExprKind::ForLoop { .. }
14131413
| ExprKind::Match(..),
14141414
..
14151415
}),

‎compiler/rustc_span/src/symbol.rs

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -426,6 +426,7 @@ symbols! {
426426
async_closure,
427427
async_fn_in_trait,
428428
async_fn_track_caller,
429+
async_for_loop,
429430
async_iterator,
430431
atomic,
431432
atomic_mod,

‎src/tools/clippy/clippy_lints/src/needless_continue.rs

Lines changed: 5 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -220,7 +220,11 @@ where
220220
F: FnMut(&ast::Block, Option<&ast::Label>),
221221
{
222222
if let ast::ExprKind::While(_, loop_block, label)
223-
| ast::ExprKind::ForLoop(_, _, loop_block, label)
223+
| ast::ExprKind::ForLoop {
224+
body: loop_block,
225+
label,
226+
..
227+
}
224228
| ast::ExprKind::Loop(loop_block, label, ..) = &expr.kind
225229
{
226230
func(loop_block, label.as_ref());

‎src/tools/clippy/clippy_lints/src/redundant_else.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -111,7 +111,7 @@ impl<'ast> Visitor<'ast> for BreakVisitor {
111111
ExprKind::If(_, ref then, Some(ref els)) => self.check_block(then) && self.check_expr(els),
112112
ExprKind::If(_, _, None)
113113
// ignore loops for simplicity
114-
| ExprKind::While(..) | ExprKind::ForLoop(..) | ExprKind::Loop(..) => false,
114+
| ExprKind::While(..) | ExprKind::ForLoop { .. } | ExprKind::Loop(..) => false,
115115
_ => {
116116
walk_expr(self, expr);
117117
return;

‎src/tools/clippy/clippy_lints/src/suspicious_operation_groupings.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -554,7 +554,7 @@ fn ident_difference_expr_with_base_location(
554554
| (Closure(_), Closure(_))
555555
| (Match(_, _), Match(_, _))
556556
| (Loop(_, _, _), Loop(_, _, _))
557-
| (ForLoop(_, _, _, _), ForLoop(_, _, _, _))
557+
| (ForLoop { .. }, ForLoop { .. })
558558
| (While(_, _, _), While(_, _, _))
559559
| (If(_, _, _), If(_, _, _))
560560
| (Let(_, _, _, _), Let(_, _, _, _))

‎src/tools/clippy/clippy_utils/src/ast_utils.rs

Lines changed: 16 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -169,9 +169,22 @@ pub fn eq_expr(l: &Expr, r: &Expr) -> bool {
169169
(Let(lp, le, _, _), Let(rp, re, _, _)) => eq_pat(lp, rp) && eq_expr(le, re),
170170
(If(lc, lt, le), If(rc, rt, re)) => eq_expr(lc, rc) && eq_block(lt, rt) && eq_expr_opt(le, re),
171171
(While(lc, lt, ll), While(rc, rt, rl)) => eq_label(ll, rl) && eq_expr(lc, rc) && eq_block(lt, rt),
172-
(ForLoop(lp, li, lt, ll), ForLoop(rp, ri, rt, rl)) => {
173-
eq_label(ll, rl) && eq_pat(lp, rp) && eq_expr(li, ri) && eq_block(lt, rt)
174-
},
172+
(
173+
ForLoop {
174+
pat: lp,
175+
iter: li,
176+
body: lt,
177+
label: ll,
178+
kind: lk,
179+
},
180+
ForLoop {
181+
pat: rp,
182+
iter: ri,
183+
body: rt,
184+
label: rl,
185+
kind: rk,
186+
},
187+
) => eq_label(ll, rl) && eq_pat(lp, rp) && eq_expr(li, ri) && eq_block(lt, rt) && lk == rk,
175188
(Loop(lt, ll, _), Loop(rt, rl, _)) => eq_label(ll, rl) && eq_block(lt, rt),
176189
(Block(lb, ll), Block(rb, rl)) => eq_label(ll, rl) && eq_block(lb, rb),
177190
(TryBlock(l), TryBlock(r)) => eq_block(l, r),

‎src/tools/clippy/clippy_utils/src/sugg.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -197,7 +197,7 @@ impl<'a> Sugg<'a> {
197197
| ast::ExprKind::Continue(..)
198198
| ast::ExprKind::Yield(..)
199199
| ast::ExprKind::Field(..)
200-
| ast::ExprKind::ForLoop(..)
200+
| ast::ExprKind::ForLoop { .. }
201201
| ast::ExprKind::Index(..)
202202
| ast::ExprKind::InlineAsm(..)
203203
| ast::ExprKind::OffsetOf(..)

‎src/tools/rustfmt/src/closures.rs

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -448,7 +448,7 @@ fn is_block_closure_forced(context: &RewriteContext<'_>, expr: &ast::Expr) -> bo
448448

449449
fn is_block_closure_forced_inner(expr: &ast::Expr, version: Version) -> bool {
450450
match expr.kind {
451-
ast::ExprKind::If(..) | ast::ExprKind::While(..) | ast::ExprKind::ForLoop(..) => true,
451+
ast::ExprKind::If(..) | ast::ExprKind::While(..) | ast::ExprKind::ForLoop { .. } => true,
452452
ast::ExprKind::Loop(..) if version == Version::Two => true,
453453
ast::ExprKind::AddrOf(_, _, ref expr)
454454
| ast::ExprKind::Try(ref expr)
@@ -473,7 +473,7 @@ fn expr_requires_semi_to_be_stmt(e: &ast::Expr) -> bool {
473473
| ast::ExprKind::Block(..)
474474
| ast::ExprKind::While(..)
475475
| ast::ExprKind::Loop(..)
476-
| ast::ExprKind::ForLoop(..)
476+
| ast::ExprKind::ForLoop { .. }
477477
| ast::ExprKind::TryBlock(..) => false,
478478
_ => true,
479479
}

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