error: non-binding let on a type that implements `Drop`
  --> $DIR/box_vec.rs:7:9
   |
LL |         let _: Box<$x> = Box::new($init);
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...
LL |     boxit!(Vec::new(), Vec<u8>);
   |     ---------------------------- in this macro invocation
   |
   = 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`
   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)

error: you seem to be trying to use `Box<Vec<T>>`. Consider using just `Vec<T>`
  --> $DIR/box_vec.rs:14:18
   |
LL | pub fn test(foo: Box<Vec<bool>>) {
   |                  ^^^^^^^^^^^^^^
   |
   = note: `-D clippy::box-vec` implied by `-D warnings`
   = help: `Vec<T>` is already on the heap, `Box<Vec<T>>` makes an extra allocation.

error: aborting due to 2 previous errors