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Add test to map_flatten with an Option

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This commit is contained in:
Marcin Serwin 2020-04-15 19:06:41 +02:00
parent c20afbdfe0
commit 72a8fc24e6
3 changed files with 9 additions and 1 deletions
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1
tests/ui/map_flatten.fixed
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@ -5,4 +5,5 @@
fn main() {
let _: Vec<_> = vec![5_i8; 6].into_iter().flat_map(|x| 0..x).collect();
let _: Option<_> = (Some(Some(1))).and_then(|x| x);
}

1
tests/ui/map_flatten.rs
View file

@ -5,4 +5,5 @@
fn main() {
let _: Vec<_> = vec![5_i8; 6].into_iter().map(|x| 0..x).flatten().collect();
let _: Option<_> = (Some(Some(1))).map(|x| x).flatten();
}

8
tests/ui/map_flatten.stderr
View file

@ -6,5 +6,11 @@ LL | let _: Vec<_> = vec![5_i8; 6].into_iter().map(|x| 0..x).flatten().colle
|
= note: `-D clippy::map-flatten` implied by `-D warnings`
error: aborting due to previous error
error: called `map(..).flatten()` on an `Option`. This is more succinctly expressed by calling `.and_then(..)`
--> $DIR/map_flatten.rs:8:24
|
LL | let _: Option<_> = (Some(Some(1))).map(|x| x).flatten();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try using `and_then` instead: `(Some(Some(1))).and_then(|x| x)`
error: aborting due to 2 previous errors