= help: the trait `std::ops::Try` is not implemented for `()` = note: required by `std::ops::Try::from_error` error: aborting due to previous error For more information about this error, try `rustc --explain E0277`. error: could not compile `cargo_learn`. To learn more, run...
; | ^ the trait `std::convert::From<redis::RedisError>` is not implemented for `errors::MyError` 从错误信息中,我们可以看出我们要处理的是redis::RedisError,需要将其转化为MyError。这个转换需要通过std::convert::From<redis::RedisError>来实现,但是我们使用derive_more::From来帮助我们完成,省去...
use std::fs::File;use std::io::ErrorKind;fn main() {let f = File::open("hello.txt");let f = match f {Ok(file) => file,Err(error) => match error.kind() {ErrorKind::NotFound => match File::create("hello.txt") {Ok(fc) => fc,Err(e) => panic!("Problem creating the...
fn match_for_io_error(err_status: &Status) -> Option<&std::io::Error> { let mut err: &(dyn Error + 'static) = err_status; loop { if let Some(io_err) = err.downcast_ref::<std::io::Error>() { return Some(io_err); } // h2::Error do not expose std::io::Error with ...
Could not compile `testproject`. This is confusing. The traitBisimplemented for the typeBImpl. Instead, I have to change this: impl<BImpl> A<BImpl> for AImpl ...into this: impl A<BImpl> for AImpl The error should make that clear. ...
When a function returns Option<T> and the function is basically a wrapper on an Arc<RwLock<Option<T>>> but T does not implement Clone then the code self.value.read().unwrap().as_ref().map(|value| value.clone()) will show a compile error "mismatched types" as the return type is ...
error[E0277]: `Student` doesn't implement `Debug` --> E:\.rs\struct2.rs:31:22 | 31 | println!("{:?}", s); | ^ `Student` cannot be formatted using `{:?}` | = help: the trait `Debug` is not implemented for `Student` ...
func readFile(path string) (string, error) { dat, err := ioutil.ReadFile(path) //读取文件内容 if err != nil { //判断err是否为nil return "", err //不为nil,返回err结果 } return string(dat), nil //err=nil,返回读取文件内容 ...
asyncfnmy_async_fn(){// async logic here}#[tokio::main]asyncfnmain(){letmut future=my_async_fn();(&mut future).await;// error:// within `impl Future<Output = ()>`, the trait `Unpin` is not implemented for `[async fn body@src/main.rs:1:24: 3:2]`} ...
error[E0277]:thetraitbound`String:ImportantTrait<i32>`isnotsatisfied -->src/main.rs:12:18 | 12|use_my_trait(String::new); |---^^^thetrait`ImportantTrait<i32>`isnotimplementedfor`String` || |requiredbyaboundintroducedbythiscall Assertingunsafepreconditions - 断言...