Auto merge of #9071 - Alexendoo:8734, r=dswij

Uncomment test for #8734

I believe the issue was an interaction between rustfix and `span_lint_and_sugg_for_edges`, so this would've been fixed by rust-lang/rust#98261 (Thanks, `@WaffleLapkin!)`

Closes #8734

changelog: none

Author: bors

tests/ui/map_flatten_fixable.fixed

@@ -34,21 +34,20 @@ fn main() {
 }
 
 fn issue8734() {
-    //     let _ = [0u8, 1, 2, 3]
-    //         .into_iter()
-    //         .map(|n| match n {
-    //             1 => [n
-    //                 .saturating_add(1)
-    //                 .saturating_add(1)
-    //                 .saturating_add(1)
-    //                 .saturating_add(1)
-    //                 .saturating_add(1)
-    //                 .saturating_add(1)
-    //                 .saturating_add(1)
-    //                 .saturating_add(1)],
-    //             n => [n],
-    //         })
-    //         .flatten();
+    let _ = [0u8, 1, 2, 3]
+        .into_iter()
+        .flat_map(|n| match n {
+            1 => [n
+                .saturating_add(1)
+                .saturating_add(1)
+                .saturating_add(1)
+                .saturating_add(1)
+                .saturating_add(1)
+                .saturating_add(1)
+                .saturating_add(1)
+                .saturating_add(1)],
+            n => [n],
+        });
 }
 
 #[allow(clippy::bind_instead_of_map)] // map + flatten will be suggested to `and_then`, but afterwards `map` is suggested again

tests/ui/map_flatten_fixable.rs

@@ -34,21 +34,21 @@ fn main() {
 }
 
 fn issue8734() {
-    //     let _ = [0u8, 1, 2, 3]
-    //         .into_iter()
-    //         .map(|n| match n {
-    //             1 => [n
-    //                 .saturating_add(1)
-    //                 .saturating_add(1)
-    //                 .saturating_add(1)
-    //                 .saturating_add(1)
-    //                 .saturating_add(1)
-    //                 .saturating_add(1)
-    //                 .saturating_add(1)
-    //                 .saturating_add(1)],
-    //             n => [n],
-    //         })
-    //         .flatten();
+    let _ = [0u8, 1, 2, 3]
+        .into_iter()
+        .map(|n| match n {
+            1 => [n
+                .saturating_add(1)
+                .saturating_add(1)
+                .saturating_add(1)
+                .saturating_add(1)
+                .saturating_add(1)
+                .saturating_add(1)
+                .saturating_add(1)
+                .saturating_add(1)],
+            n => [n],
+        })
+        .flatten();
 }
 
 #[allow(clippy::bind_instead_of_map)] // map + flatten will be suggested to `and_then`, but afterwards `map` is suggested again

tests/ui/map_flatten_fixable.stderr

@@ -42,6 +42,35 @@ error: called `map(..).flatten()` on `Result`
 LL |     let _: Result<_, &str> = (Ok(Ok(1))).map(|x| x).flatten();
    |                                          ^^^^^^^^^^^^^^^^^^^^ help: try replacing `map` with `and_then` and remove the `.flatten()`: `and_then(|x| x)`
 
+error: called `map(..).flatten()` on `Iterator`
+  --> $DIR/map_flatten_fixable.rs:39:10
+   |
+LL |           .map(|n| match n {
+   |  __________^
+LL | |             1 => [n
+LL | |                 .saturating_add(1)
+LL | |                 .saturating_add(1)
+...  |
+LL | |         })
+LL | |         .flatten();
+   | |__________________^
+   |
+help: try replacing `map` with `flat_map` and remove the `.flatten()`
+   |
+LL ~         .flat_map(|n| match n {
+LL +             1 => [n
+LL +                 .saturating_add(1)
+LL +                 .saturating_add(1)
+LL +                 .saturating_add(1)
+LL +                 .saturating_add(1)
+LL +                 .saturating_add(1)
+LL +                 .saturating_add(1)
+LL +                 .saturating_add(1)
+LL +                 .saturating_add(1)],
+LL +             n => [n],
+LL ~         });
+   |
+
 error: called `map(..).flatten()` on `Option`
   --> $DIR/map_flatten_fixable.rs:59:10
    |
@@ -66,5 +95,5 @@ LL +  // whitespace beforehand is important as well
 LL ~         });
    |
 
-error: aborting due to 8 previous errors
+error: aborting due to 9 previous errors