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Rollup merge of #141932 - azhogin:azhogin/async-drop-inside-asyncgen-fix, r=oli-obk

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Fix for async drop inside async gen fn

Return value (for yield) is corrected for async drop inside async gen function.
In CFG, when internal async drop future is polled and returned `Poll<()>::Pending`, then async gen resume function returns `Poll<(OptRet)>::Pending`.

Fixes rust-lang/rust#140530
This commit is contained in:
Matthias Krüger 2025-06-04 19:50:21 +02:00 • committed by GitHub
commit 9ec41bcf72
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2 changed files with 31 additions and 8 deletions
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34
compiler/rustc_mir_transform/src/coroutine/drop.rs
View file

@ -382,12 +382,34 @@ pub(super) fn expand_async_drops<'tcx>(
dropline_call_bb = Some(drop_call_bb);
}
// value needed only for return-yields or gen-coroutines, so just const here
let value = Operand::Constant(Box::new(ConstOperand {
span: body.span,
user_ty: None,
const_: Const::from_bool(tcx, false),
}));
let value =
if matches!(coroutine_kind, CoroutineKind::Desugared(CoroutineDesugaring::AsyncGen, _))
{
// For AsyncGen we need `yield Poll<OptRet>::Pending`
let full_yield_ty = body.yield_ty().unwrap();
let ty::Adt(_poll_adt, args) = *full_yield_ty.kind() else { bug!() };
let ty::Adt(_option_adt, args) = *args.type_at(0).kind() else { bug!() };
let yield_ty = args.type_at(0);
Operand::Constant(Box::new(ConstOperand {
span: source_info.span,
const_: Const::Unevaluated(
UnevaluatedConst::new(
tcx.require_lang_item(LangItem::AsyncGenPending, None),
tcx.mk_args(&[yield_ty.into()]),
),
full_yield_ty,
),
user_ty: None,
}))
} else {
// value needed only for return-yields or gen-coroutines, so just const here
Operand::Constant(Box::new(ConstOperand {
span: body.span,
user_ty: None,
const_: Const::from_bool(tcx, false),
}))
};
use rustc_middle::mir::AssertKind::ResumedAfterDrop;
let panic_bb = insert_panic_block(tcx, body, ResumedAfterDrop(coroutine_kind));