error: useless lint attribute
  --> tests/ui/useless_attribute.rs:8:1
   |
LL | #[allow(dead_code)]
   | ^^^^^^^^^^^^^^^^^^^ help: if you just forgot a `!`, use: `#![allow(dead_code)]`
   |
   = note: `-D clippy::useless-attribute` implied by `-D warnings`
   = help: to override `-D warnings` add `#[allow(clippy::useless_attribute)]`

error: useless lint attribute
  --> tests/ui/useless_attribute.rs:9:1
   |
LL | #[cfg_attr(clippy, allow(dead_code))]
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: if you just forgot a `!`, use: `#![cfg_attr(clippy, allow(dead_code)`

error: useless lint attribute
  --> tests/ui/useless_attribute.rs:20:5
   |
LL |     #[allow(clippy::almost_swapped)]
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: if you just forgot a `!`, use: `#![allow(clippy::almost_swapped)]`

error: aborting due to 3 previous errors