error: non-binding `let` on a type that implements `Drop`
  --> $DIR/let_underscore_drop.rs:17:5
   |
LL |     let _ = Box::new(());
   |     ^^^^^^^^^^^^^^^^^^^^^
   |
   = note: `-D clippy::let-underscore-drop` implied by `-D warnings`
   = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop`

error: non-binding `let` on a type that implements `Drop`
  --> $DIR/let_underscore_drop.rs:18:5
   |
LL |     let _ = Droppable;
   |     ^^^^^^^^^^^^^^^^^^
   |
   = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop`

error: non-binding `let` on a type that implements `Drop`
  --> $DIR/let_underscore_drop.rs:19:5
   |
LL |     let _ = Some(Droppable);
   |     ^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop`

error: aborting due to 3 previous errors