error: you seem to be trying to use `Box<Vec<..>>`. Consider using just `Vec<..>`
  --> $DIR/box_collection.rs:21:14
   |
LL | fn test(foo: Box<Vec<bool>>) {}
   |              ^^^^^^^^^^^^^^
   |
   = note: `-D clippy::box-collection` implied by `-D warnings`
   = help: `Vec<..>` is already on the heap, `Box<Vec<..>>` makes an extra allocation

error: you seem to be trying to use `Box<String>`. Consider using just `String`
  --> $DIR/box_collection.rs:28:15
   |
LL | fn test3(foo: Box<String>) {}
   |               ^^^^^^^^^^^
   |
   = help: `String` is already on the heap, `Box<String>` makes an extra allocation

error: you seem to be trying to use `Box<HashMap<..>>`. Consider using just `HashMap<..>`
  --> $DIR/box_collection.rs:30:15
   |
LL | fn test4(foo: Box<HashMap<String, String>>) {}
   |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: `HashMap<..>` is already on the heap, `Box<HashMap<..>>` makes an extra allocation

error: aborting due to 3 previous errors