bjoernager/rust
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Don't implement AsyncFn for FnDef/FnPtr that wouldnt implement Fn

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This commit is contained in:
Michael Goulet 2024-08-07 12:36:41 -04:00
parent 9bad7ba324
commit ec1c424293
6 changed files with 139 additions and 23 deletions
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60
compiler/rustc_next_trait_solver/src/solve/assembly/structural_traits.rs
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@ -458,28 +458,23 @@ pub(in crate::solve) fn extract_tupled_inputs_and_output_from_async_callable<I:
))
}
ty::FnDef(..) | ty::FnPtr(..) => {
let bound_sig = self_ty.fn_sig(cx);
let sig = bound_sig.skip_binder();
let future_trait_def_id = cx.require_lang_item(TraitSolverLangItem::Future);
// `FnDef` and `FnPtr` only implement `AsyncFn*` when their
// return type implements `Future`.
let nested = vec![
bound_sig
.rebind(ty::TraitRef::new(cx, future_trait_def_id, [sig.output()]))
.upcast(cx),
];
let future_output_def_id = cx.require_lang_item(TraitSolverLangItem::FutureOutput);
let future_output_ty = Ty::new_projection(cx, future_output_def_id, [sig.output()]);
Ok((
bound_sig.rebind(AsyncCallableRelevantTypes {
tupled_inputs_ty: Ty::new_tup(cx, sig.inputs().as_slice()),
output_coroutine_ty: sig.output(),
coroutine_return_ty: future_output_ty,
}),
nested,
))
ty::FnDef(def_id, _) => {
let sig = self_ty.fn_sig(cx);
if sig.skip_binder().is_fn_trait_compatible() && !cx.has_target_features(def_id) {
fn_item_to_async_callable(cx, sig)
} else {
Err(NoSolution)
}
}
ty::FnPtr(..) => {
let sig = self_ty.fn_sig(cx);
if sig.skip_binder().is_fn_trait_compatible() {
fn_item_to_async_callable(cx, sig)
} else {
Err(NoSolution)
}
}
ty::Closure(_, args) => {
let args = args.as_closure();
let bound_sig = args.sig();
@ -563,6 +558,29 @@ pub(in crate::solve) fn extract_tupled_inputs_and_output_from_async_callable<I:
}
}
fn fn_item_to_async_callable<I: Interner>(
cx: I,
bound_sig: ty::Binder<I, ty::FnSig<I>>,
) -> Result<(ty::Binder<I, AsyncCallableRelevantTypes<I>>, Vec<I::Predicate>), NoSolution> {
let sig = bound_sig.skip_binder();
let future_trait_def_id = cx.require_lang_item(TraitSolverLangItem::Future);
// `FnDef` and `FnPtr` only implement `AsyncFn*` when their
// return type implements `Future`.
let nested = vec![
bound_sig.rebind(ty::TraitRef::new(cx, future_trait_def_id, [sig.output()])).upcast(cx),
];
let future_output_def_id = cx.require_lang_item(TraitSolverLangItem::FutureOutput);
let future_output_ty = Ty::new_projection(cx, future_output_def_id, [sig.output()]);
Ok((
bound_sig.rebind(AsyncCallableRelevantTypes {
tupled_inputs_ty: Ty::new_tup(cx, sig.inputs().as_slice()),
output_coroutine_ty: sig.output(),
coroutine_return_ty: future_output_ty,
}),
nested,
))
}
/// Given a coroutine-closure, project to its returned coroutine when we are *certain*
/// that the closure's kind is compatible with the goal.
fn coroutine_closure_to_certain_coroutine<I: Interner>(