bjoernager/rust
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More comments, final tweaks

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This commit is contained in:
Michael Goulet 2024-01-25 19:17:21 +00:00
parent 37184e86ea
commit c98d6994a3
20 changed files with 169 additions and 42 deletions
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24
compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs
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@ -309,14 +309,19 @@ pub(in crate::solve) fn extract_tupled_inputs_and_output_from_callable<'tcx>(
}
// Returns a binder of the tupled inputs types, output type, and coroutine type
// from a builtin async closure type.
// from a builtin coroutine-closure type. If we don't yet know the closure kind of
// the coroutine-closure, emit an additional trait predicate for `AsyncFnKindHelper`
// which enforces the closure is actually callable with the given trait. When we
// know the kind already, we can short-circuit this check.
pub(in crate::solve) fn extract_tupled_inputs_and_output_from_async_callable<'tcx>(
tcx: TyCtxt<'tcx>,
self_ty: Ty<'tcx>,
goal_kind: ty::ClosureKind,
env_region: ty::Region<'tcx>,
) -> Result<(ty::Binder<'tcx, (Ty<'tcx>, Ty<'tcx>, Ty<'tcx>)>, Vec<ty::Predicate<'tcx>>), NoSolution>
{
) -> Result<
(ty::Binder<'tcx, (Ty<'tcx>, Ty<'tcx>, Ty<'tcx>)>, Option<ty::Predicate<'tcx>>),
NoSolution,
> {
match *self_ty.kind() {
ty::CoroutineClosure(def_id, args) => {
let args = args.as_coroutine_closure();
@ -339,7 +344,7 @@ pub(in crate::solve) fn extract_tupled_inputs_and_output_from_async_callable<'tc
);
(sig.tupled_inputs_ty, sig.return_ty, coroutine_ty)
}),
vec![],
None,
))
} else {
let async_fn_kind_trait_def_id =
@ -350,6 +355,13 @@ pub(in crate::solve) fn extract_tupled_inputs_and_output_from_async_callable<'tc
.next()
.unwrap()
.def_id;
// When we don't know the closure kind (and therefore also the closure's upvars,
// which are computed at the same time), we must delay the computation of the
// generator's upvars. We do this using the `AsyncFnKindHelper`, which as a trait
// goal functions similarly to the old `ClosureKind` predicate, and ensures that
// the goal kind <= the closure kind. As a projection `AsyncFnKindHelper::Upvars`
// will project to the right upvars for the generator, appending the inputs and
// coroutine upvars respecting the closure kind.
Ok((
args.coroutine_closure_sig().map_bound(|sig| {
let tupled_upvars_ty = Ty::new_projection(
@ -373,14 +385,14 @@ pub(in crate::solve) fn extract_tupled_inputs_and_output_from_async_callable<'tc
);
(sig.tupled_inputs_ty, sig.return_ty, coroutine_ty)
}),
vec![
Some(
ty::TraitRef::new(
tcx,
async_fn_kind_trait_def_id,
[kind_ty, Ty::from_closure_kind(tcx, goal_kind)],
)
.to_predicate(tcx),
],
),
))
}
}