error[E0493]: destructor of `Box<T>` cannot be evaluated at compile-time
  --> $DIR/drop_box.rs:1:15
   |
LL | const fn f<T>(_: Box<T>) {}
   |               ^           - value is dropped here
   |               |
   |               the destructor for this type cannot be evaluated in constant functions

error: aborting due to previous error

For more information about this error, try `rustc --explain E0493`.