rust/tests/ui/try_err.rs
Tomasz Miąsko e9677105bf try_err: Consider Try impl for Poll when generating suggestions
There are two different implementation of Try trait for Poll type;
Poll<Result<T, E>> and Poll<Option<Result<T, E>>>. Take them into
account when generating suggestions.

For example, for Err(e)? suggest either return Poll::Ready(Err(e)) or
return Poll::Ready(Some(Err(e))) as appropriate.
2020-08-03 20:48:18 +02:00

127 lines
2.5 KiB
Rust

// run-rustfix
// aux-build:macro_rules.rs
#![deny(clippy::try_err)]
#[macro_use]
extern crate macro_rules;
use std::io;
use std::task::Poll;
// Tests that a simple case works
// Should flag `Err(err)?`
pub fn basic_test() -> Result<i32, i32> {
let err: i32 = 1;
// To avoid warnings during rustfix
if true {
Err(err)?;
}
Ok(0)
}
// Tests that `.into()` is added when appropriate
pub fn into_test() -> Result<i32, i32> {
let err: u8 = 1;
// To avoid warnings during rustfix
if true {
Err(err)?;
}
Ok(0)
}
// Tests that tries in general don't trigger the error
pub fn negative_test() -> Result<i32, i32> {
Ok(nested_error()? + 1)
}
// Tests that `.into()` isn't added when the error type
// matches the surrounding closure's return type, even
// when it doesn't match the surrounding function's.
pub fn closure_matches_test() -> Result<i32, i32> {
let res: Result<i32, i8> = Some(1)
.into_iter()
.map(|i| {
let err: i8 = 1;
// To avoid warnings during rustfix
if true {
Err(err)?;
}
Ok(i)
})
.next()
.unwrap();
Ok(res?)
}
// Tests that `.into()` isn't added when the error type
// doesn't match the surrounding closure's return type.
pub fn closure_into_test() -> Result<i32, i32> {
let res: Result<i32, i16> = Some(1)
.into_iter()
.map(|i| {
let err: i8 = 1;
// To avoid warnings during rustfix
if true {
Err(err)?;
}
Ok(i)
})
.next()
.unwrap();
Ok(res?)
}
fn nested_error() -> Result<i32, i32> {
Ok(1)
}
fn main() {
basic_test().unwrap();
into_test().unwrap();
negative_test().unwrap();
closure_matches_test().unwrap();
closure_into_test().unwrap();
// We don't want to lint in external macros
try_err!();
}
macro_rules! bar {
() => {
String::from("aasdfasdfasdfa")
};
}
macro_rules! foo {
() => {
bar!()
};
}
pub fn macro_inside(fail: bool) -> Result<i32, String> {
if fail {
Err(foo!())?;
}
Ok(0)
}
pub fn poll_write(n: usize) -> Poll<io::Result<usize>> {
if n == 0 {
Err(io::ErrorKind::WriteZero)?
} else if n == 1 {
Err(io::Error::new(io::ErrorKind::InvalidInput, "error"))?
};
Poll::Ready(Ok(n))
}
pub fn poll_next(ready: bool) -> Poll<Option<io::Result<()>>> {
if !ready {
Err(io::ErrorKind::NotFound)?
}
Poll::Ready(None)
}