error: this call to `map()` won't have an effect on the call to `count()`
  --> $DIR/suspicious_map.rs:4:13
   |
LL |     let _ = (0..3).map(|x| x + 2).count();
   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: `-D clippy::suspicious-map` implied by `-D warnings`
   = help: make sure you did not confuse `map` with `filter` or `for_each`

error: aborting due to previous error