error: useless use of `format!`
 --> $DIR/format.rs:6:5
  |
6 |     format!("foo");
  |     ^^^^^^^^^^^^^^^
  |
  = note: `-D useless-format` implied by `-D warnings`

error: useless use of `format!`
 --> $DIR/format.rs:8:5
  |
8 |     format!("{}", "foo");
  |     ^^^^^^^^^^^^^^^^^^^^^

error: useless use of `format!`
  --> $DIR/format.rs:15:5
   |
15 |     format!("{}", arg);
   |     ^^^^^^^^^^^^^^^^^^^

error: aborting due to 3 previous errors