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#![feature(type_alias_impl_trait)]
//@ edition:2021
use std::future::Future;
struct Connection {}
trait Transaction {}
struct TestTransaction<'conn> {
conn: &'conn Connection,
}
impl<'conn> Transaction for TestTransaction<'conn> {}
struct Context {}
type TransactionResult<O> = Result<O, ()>;
type TransactionFuture<'__, O> = impl '__ + Future<Output = TransactionResult<O>>;
#[define_opaque(TransactionFuture)]
fn execute_transaction_fut<'f, F, O>(
//~^ ERROR: item does not constrain
f: F,
) -> impl FnOnce(&mut dyn Transaction) -> TransactionFuture<'_, O>
where
F: FnOnce(&mut dyn Transaction) -> TransactionFuture<'_, O> + 'f,
{
f
}
impl Context {
#[define_opaque(TransactionFuture)]
async fn do_transaction<O>(
//~^ ERROR: item does not constrain
&self,
f: impl FnOnce(&mut dyn Transaction) -> TransactionFuture<'_, O>,
) -> TransactionResult<O> {
let mut conn = Connection {};
let mut transaction = TestTransaction { conn: &mut conn };
f(&mut transaction).await
}
}
fn main() {}
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