error: unused variable: `rest`
  --> $DIR/issue-81314-unused-span-ident.rs:8:10
   |
LL |     let [rest @ ..] = [1, 2, 3];
   |          ^^^^ help: if this is intentional, prefix it with an underscore: `_rest`
   |
note: the lint level is defined here
  --> $DIR/issue-81314-unused-span-ident.rs:5:9
   |
LL | #![deny(unused)]
   |         ^^^^^^
   = note: `#[deny(unused_variables)]` implied by `#[deny(unused)]`

error: unused variable: `rest`
  --> $DIR/issue-81314-unused-span-ident.rs:11:13
   |
LL | pub fn foo([rest @ ..]: &[i32]) {
   |             ^^^^ help: if this is intentional, prefix it with an underscore: `_rest`

error: aborting due to 2 previous errors