warning: named argument `_x` is not used by name
  --> $DIR/issue-98466.rs:7:26
   |
LL |     println!("_x is {}", _x = 5);
   |                     --   ^^ this named argument is referred to by position in formatting string
   |                     |
   |                     this formatting argument uses named argument `_x` by position
   |
   = note: `#[warn(named_arguments_used_positionally)]` on by default
help: use the named argument by name to avoid ambiguity
   |
LL |     println!("_x is {_x}", _x = 5);
   |                      ++

warning: named argument `y` is not used by name
  --> $DIR/issue-98466.rs:10:26
   |
LL |     println!("_x is {}", y = _x);
   |                     --   ^ this named argument is referred to by position in formatting string
   |                     |
   |                     this formatting argument uses named argument `y` by position
   |
help: use the named argument by name to avoid ambiguity
   |
LL |     println!("_x is {y}", y = _x);
   |                      +

warning: named argument `y` is not used by name
  --> $DIR/issue-98466.rs:13:83
   |
LL |     println!("first positional arg {}, second positional arg {}, _x is {}", 1, 2, y = _x);
   |                                                                        --         ^ this named argument is referred to by position in formatting string
   |                                                                        |
   |                                                                        this formatting argument uses named argument `y` by position
   |
help: use the named argument by name to avoid ambiguity
   |
LL |     println!("first positional arg {}, second positional arg {}, _x is {y}", 1, 2, y = _x);
   |                                                                         +

warning: named argument `_x` is not used by name
  --> $DIR/issue-98466.rs:19:34
   |
LL |     let _f = format!("_x is {}", _x = 5);
   |                             --   ^^ this named argument is referred to by position in formatting string
   |                             |
   |                             this formatting argument uses named argument `_x` by position
   |
help: use the named argument by name to avoid ambiguity
   |
LL |     let _f = format!("_x is {_x}", _x = 5);
   |                              ++

warning: named argument `y` is not used by name
  --> $DIR/issue-98466.rs:22:34
   |
LL |     let _f = format!("_x is {}", y = _x);
   |                             --   ^ this named argument is referred to by position in formatting string
   |                             |
   |                             this formatting argument uses named argument `y` by position
   |
help: use the named argument by name to avoid ambiguity
   |
LL |     let _f = format!("_x is {y}", y = _x);
   |                              +

warning: named argument `y` is not used by name
  --> $DIR/issue-98466.rs:25:91
   |
LL |     let _f = format!("first positional arg {}, second positional arg {}, _x is {}", 1, 2, y = _x);
   |                                                                                --         ^ this named argument is referred to by position in formatting string
   |                                                                                |
   |                                                                                this formatting argument uses named argument `y` by position
   |
help: use the named argument by name to avoid ambiguity
   |
LL |     let _f = format!("first positional arg {}, second positional arg {}, _x is {y}", 1, 2, y = _x);
   |                                                                                 +

warning: 6 warnings emitted