error: valid forms for the attribute are `#[inline(always)]`, `#[inline(never)]`, and `#[inline]`
  --> $DIR/lint_on_root.rs:3:1
   |
LL | #![inline = ""]
   | ^^^^^^^^^^^^^^^
   |
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #57571 <https://github.com/rust-lang/rust/issues/57571>
   = note: `#[deny(ill_formed_attribute_input)]` on by default

error: aborting due to 1 previous error

Future incompatibility report: Future breakage diagnostic:
error: valid forms for the attribute are `#[inline(always)]`, `#[inline(never)]`, and `#[inline]`
  --> $DIR/lint_on_root.rs:3:1
   |
LL | #![inline = ""]
   | ^^^^^^^^^^^^^^^
   |
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #57571 <https://github.com/rust-lang/rust/issues/57571>
   = note: `#[deny(ill_formed_attribute_input)]` on by default