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fn new_coroutine_witness_for_coroutine woops

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This commit is contained in:
lcnr
2025-08-12 16:33:21 +02:00
parent 3339fa5fcc
commit f979bf018f
4 changed files with 63 additions and 61 deletions
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61
compiler/rustc_trait_selection/src/traits/select/mod.rs
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@@ -4,9 +4,9 @@
use std::assert_matches::assert_matches;
use std::cell::{Cell, RefCell};
use std::cmp;
use std::fmt::{self, Display};
use std::ops::ControlFlow;
use std::{cmp, iter};
use hir::def::DefKind;
use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
@@ -2185,32 +2185,23 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
ty::Binder::dummy(vec![ty])
}
ty::Coroutine(coroutine_def_id, args) => {
match self.tcx().coroutine_movability(coroutine_def_id) {
hir::Movability::Static => {
unreachable!("tried to assemble `Sized` for static coroutine")
}
hir::Movability::Movable => {
if self.tcx().features().coroutine_clone() {
ty::Binder::dummy(
args.as_coroutine()
.upvar_tys()
.iter()
.chain([Ty::new_coroutine_witness(
self.tcx(),
coroutine_def_id,
self.tcx().mk_args(args.as_coroutine().parent_args()),
)])
.collect::<Vec<_>>(),
)
} else {
unreachable!(
"tried to assemble `Sized` for coroutine without enabled feature"
)
}
ty::Coroutine(def_id, args) => match self.tcx().coroutine_movability(def_id) {
hir::Movability::Static => {
unreachable!("tried to assemble `Clone` for static coroutine")
}
hir::Movability::Movable => {
if self.tcx().features().coroutine_clone() {
ty::Binder::dummy(vec![
args.as_coroutine().tupled_upvars_ty(),
Ty::new_coroutine_witness_for_coroutine(self.tcx(), def_id, args),
])
} else {
unreachable!(
"tried to assemble `Clone` for coroutine without enabled feature"
)
}
}
}
},
ty::CoroutineWitness(def_id, args) => self
.infcx
@@ -2334,25 +2325,9 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
ty::Coroutine(def_id, args) => {
let ty = self.infcx.shallow_resolve(args.as_coroutine().tupled_upvars_ty());
let tcx = self.tcx();
let witness = Ty::new_coroutine_witness(
tcx,
def_id,
ty::GenericArgs::for_item(tcx, def_id, |def, _| match def.kind {
// HACK: Coroutine witnesse types are lifetime erased, so they
// never reference any lifetime args from the coroutine. We erase
// the regions here since we may get into situations where a
// coroutine is recursively contained within itself, leading to
// witness types that differ by region args. This means that
// cycle detection in fulfillment will not kick in, which leads
// to unnecessary overflows in async code. See the issue:
// <https://github.com/rust-lang/rust/issues/145151>.
ty::GenericParamDefKind::Lifetime => tcx.lifetimes.re_erased.into(),
ty::GenericParamDefKind::Type { .. }
| ty::GenericParamDefKind::Const { .. } => args[def.index as usize],
}),
);
let witness = Ty::new_coroutine_witness_for_coroutine(tcx, def_id, args);
ty::Binder::dummy(AutoImplConstituents {
types: [ty].into_iter().chain(iter::once(witness)).collect(),
types: vec![ty, witness],
assumptions: vec![],
})
}