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