Is there any way to create an alias of a specific FnMut?

I want to work with FnMut(&[f32]) -> f32, to not copy/paste full signature, I want to introduce some kind of alias, but

type Boo = FnMut(&[f32]) -> f32;

fn f<F: Boo>(mut f: F) {}

Causes a compiler error:

error[E0404]: expected trait, found type alias `Boo`
 --> src/main.rs:3:13
  |
3 |     fn f<F: Boo>(mut f: F) {}
  |             ^^^ type aliases cannot be used for traits

I then tried:

trait Boo: FnMut(&[f32]) -> f32 {}

fn f<F: Boo>(mut f: F) {}

it compiled, but if I try to use Boo in place of trait in another place:

trait Boo: FnMut(&[f32]) -> f32 {}

struct X(Vec<Box<Boo>>);

I get:

error[E0191]: the value of the associated type `Output` (from the trait `std::ops::FnOnce`) must be specified
 --> src/main.rs:3:18
  |
3 | struct X(Vec<Box<Boo>>);
  |                  ^^^ missing associated type `Output` value

Is there any way to create an alias of a specific FnMut which I can use instead of FnMut(&[f32]) -> f32?