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Make sure we check the future type is Sized in AsyncFn*

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This commit is contained in:
Michael Goulet 2024-12-30 18:59:49 +00:00
parent 93722f7ed5
commit ed9a4cfdeb
3 changed files with 71 additions and 3 deletions
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23
compiler/rustc_trait_selection/src/traits/select/confirmation.rs
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@ -896,6 +896,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
sig.tupled_inputs_ty,
])
});
// Note that unlike below, we don't need to check `Future + Sized` for
// the output coroutine because they are `Future + Sized` by construction.
(trait_ref, args.kind_ty())
}
ty::FnDef(..) | ty::FnPtr(..) => {
@ -907,7 +911,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
])
});
// We must additionally check that the return type impls `Future`.
// We must additionally check that the return type impls `Future + Sized`.
let future_trait_def_id = tcx.require_lang_item(LangItem::Future, None);
nested.push(obligation.with(
tcx,
@ -915,6 +919,13 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
ty::TraitRef::new(tcx, future_trait_def_id, [output_ty])
}),
));
let sized_trait_def_id = tcx.require_lang_item(LangItem::Sized, None);
nested.push(obligation.with(
tcx,
sig.output().map_bound(|output_ty| {
ty::TraitRef::new(tcx, sized_trait_def_id, [output_ty])
}),
));
(trait_ref, Ty::from_closure_kind(tcx, ty::ClosureKind::Fn))
}
@ -928,14 +939,20 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
])
});
// We must additionally check that the return type impls `Future`.
// See FIXME in last branch for why we instantiate the binder eagerly.
// We must additionally check that the return type impls `Future + Sized`.
let future_trait_def_id = tcx.require_lang_item(LangItem::Future, None);
let placeholder_output_ty = self.infcx.enter_forall_and_leak_universe(sig.output());
nested.push(obligation.with(
tcx,
ty::TraitRef::new(tcx, future_trait_def_id, [placeholder_output_ty]),
));
let sized_trait_def_id = tcx.require_lang_item(LangItem::Sized, None);
nested.push(obligation.with(
tcx,
sig.output().map_bound(|output_ty| {
ty::TraitRef::new(tcx, sized_trait_def_id, [output_ty])
}),
));
(trait_ref, args.kind_ty())
}