rust/tests/ui/async-await/async-block-control-flow-static-semantics.rs
2023-01-11 09:32:08 +00:00

66 lines
1.5 KiB
Rust

// Test that `async { .. }` blocks:
// 1. do not allow `break` expressions.
// 2. get targeted by `return` and not the parent function.
// 3. get targeted by `?` and not the parent function.
//
// edition:2018
fn main() {}
use core::future::Future;
fn return_targets_async_block_not_fn() -> u8 {
//~^ ERROR mismatched types
let block = async {
return 0u8;
};
let _: &dyn Future<Output = ()> = &block;
//~^ ERROR to be a future that resolves to `()`, but it resolves to `u8`
}
async fn return_targets_async_block_not_async_fn() -> u8 {
//~^ ERROR mismatched types [E0308]
let block = async {
return 0u8;
};
let _: &dyn Future<Output = ()> = &block;
//~^ ERROR to be a future that resolves to `()`, but it resolves to `u8`
}
fn no_break_in_async_block() {
async {
break 0u8; //~ ERROR `break` inside of an `async` block
};
}
fn no_break_in_async_block_even_with_outer_loop() {
loop {
async {
break 0u8; //~ ERROR `break` inside of an `async` block
};
}
}
struct MyErr;
fn err() -> Result<u8, MyErr> {
Err(MyErr)
}
fn rethrow_targets_async_block_not_fn() -> Result<u8, MyErr> {
//~^ ERROR mismatched types
let block = async {
err()?;
Ok(())
};
let _: &dyn Future<Output = Result<(), MyErr>> = &block;
}
fn rethrow_targets_async_block_not_async_fn() -> Result<u8, MyErr> {
//~^ ERROR mismatched types
let block = async {
err()?;
Ok(())
};
let _: &dyn Future<Output = Result<(), MyErr>> = &block;
}