Add test case

Author: giraffate

tests/ui/needless_collect_indirect.rs

@@ -16,4 +16,10 @@ fn main() {
         .into_iter()
         .map(|x| (*x, *x + 1))
         .collect::<HashMap<_, _>>();
+
+    // #6202
+    let a = "a".to_string();
+    let sample = vec![a.clone(), "b".to_string(), "c".to_string()];
+    let non_copy_contains = sample.into_iter().collect::<Vec<_>>();
+    non_copy_contains.contains(&a);
 }

tests/ui/needless_collect_indirect.stderr

@@ -51,5 +51,18 @@ LL |
 LL |     sample.iter().any(|x| x == &5);
    |
 
-error: aborting due to 4 previous errors
+error: avoid using `collect()` when not needed
+  --> $DIR/needless_collect_indirect.rs:23:5
+   |
+LL | /     let non_copy_contains = sample.into_iter().collect::<Vec<_>>();
+LL | |     non_copy_contains.contains(&a);
+   | |____^
+   |
+help: Check if the original Iterator contains an element instead of collecting then checking
+   |
+LL |     
+LL |     sample.into_iter().any(|x| x == a);
+   |
+
+error: aborting due to 5 previous errors