rust/tests/ui/map_flatten_fixable.rs
2022-05-24 14:41:23 +02:00

49 lines
1.6 KiB
Rust

// run-rustfix
#![warn(clippy::all, clippy::pedantic)]
#![allow(clippy::let_underscore_drop)]
#![allow(clippy::missing_docs_in_private_items)]
#![allow(clippy::map_identity)]
#![allow(clippy::redundant_closure)]
#![allow(clippy::unnecessary_wraps)]
#![feature(result_flattening)]
fn main() {
// mapping to Option on Iterator
fn option_id(x: i8) -> Option<i8> {
Some(x)
}
let option_id_ref: fn(i8) -> Option<i8> = option_id;
let option_id_closure = |x| Some(x);
let _: Vec<_> = vec![5_i8; 6].into_iter().map(option_id).flatten().collect();
let _: Vec<_> = vec![5_i8; 6].into_iter().map(option_id_ref).flatten().collect();
let _: Vec<_> = vec![5_i8; 6].into_iter().map(option_id_closure).flatten().collect();
let _: Vec<_> = vec![5_i8; 6].into_iter().map(|x| x.checked_add(1)).flatten().collect();
// mapping to Iterator on Iterator
let _: Vec<_> = vec![5_i8; 6].into_iter().map(|x| 0..x).flatten().collect();
// mapping to Option on Option
let _: Option<_> = (Some(Some(1))).map(|x| x).flatten();
// mapping to Result on Result
let _: Result<_, &str> = (Ok(Ok(1))).map(|x| x).flatten();
issue8878();
}
#[allow(clippy::bind_instead_of_map)] // map + flatten will be suggested to `and_then`, but afterwards `map` is suggested again
#[rustfmt::skip] // whitespace is important for this one
fn issue8878() {
std::collections::HashMap::<u32, u32>::new()
.get(&0)
.map(|_| {
// we need some newlines
// so that the span is big enough
// for a splitted output of the diagnostic
Some("")
// whitespace beforehand is important as well
})
.flatten();
}