error: useless use of `vec!`
  --> $DIR/vec.rs:24:14
   |
24 |     on_slice(&vec![]);
   |              ^^^^^^^ help: you can use a slice directly: `&[]`
   |
   = note: `-D useless-vec` implied by `-D warnings`

error: useless use of `vec!`
  --> $DIR/vec.rs:27:14
   |
27 |     on_slice(&vec![1, 2]);
   |              ^^^^^^^^^^^ help: you can use a slice directly: `&[1, 2]`

error: useless use of `vec!`
  --> $DIR/vec.rs:30:14
   |
30 |     on_slice(&vec ![1, 2]);
   |              ^^^^^^^^^^^^ help: you can use a slice directly: `&[1, 2]`

error: useless use of `vec!`
  --> $DIR/vec.rs:33:14
   |
33 |     on_slice(&vec!(1, 2));
   |              ^^^^^^^^^^^ help: you can use a slice directly: `&[1, 2]`

error: useless use of `vec!`
  --> $DIR/vec.rs:36:14
   |
36 |     on_slice(&vec![1; 2]);
   |              ^^^^^^^^^^^ help: you can use a slice directly: `&[1; 2]`

error: useless use of `vec!`
  --> $DIR/vec.rs:49:14
   |
49 |     for a in vec![1, 2, 3] {
   |              ^^^^^^^^^^^^^ help: you can use a slice directly: `&[1, 2, 3]`