error: missing trait in a trait impl
  --> $DIR/issue-56031.rs:3:5
   |
LL | impl for T {}
   |     ^
   |
help: add a trait here
   |
LL | impl Trait for T {}
   |      +++++
help: for an inherent impl, drop this `for`
   |
LL - impl for T {}
LL + impl T {}
   |

error: aborting due to previous error