error: useless use of `vec!`
  --> $DIR/vec.rs:23:14
   |
LL |     on_slice(&vec![]);
   |              ^^^^^^^ help: you can use a slice directly: `&[]`
   |
   = note: `-D clippy::useless-vec` implied by `-D warnings`

error: useless use of `vec!`
  --> $DIR/vec.rs:26:14
   |
LL |     on_slice(&vec![1, 2]);
   |              ^^^^^^^^^^^ help: you can use a slice directly: `&[1, 2]`

error: useless use of `vec!`
  --> $DIR/vec.rs:29:14
   |
LL |     on_slice(&vec![1, 2]);
   |              ^^^^^^^^^^^ help: you can use a slice directly: `&[1, 2]`

error: useless use of `vec!`
  --> $DIR/vec.rs:32:14
   |
LL |     on_slice(&vec!(1, 2));
   |              ^^^^^^^^^^^ help: you can use a slice directly: `&[1, 2]`

error: useless use of `vec!`
  --> $DIR/vec.rs:35:14
   |
LL |     on_slice(&vec![1; 2]);
   |              ^^^^^^^^^^^ help: you can use a slice directly: `&[1; 2]`

error: useless use of `vec!`
  --> $DIR/vec.rs:48:14
   |
LL |     for a in vec![1, 2, 3] {
   |              ^^^^^^^^^^^^^ help: you can use a slice directly: `&[1, 2, 3]`

error: aborting due to 6 previous errors