src/test/ui/const-generics/defaults/const-param-in-ty-defaults.rs

// run-pass
#![feature(const_generics_defaults)]
struct Foo<const N: usize, T = [u8; N]>(T);

impl<const N: usize> Foo<N> {
    fn new() -> Self {
        Foo([0; N])
    }
}

fn main() {
    assert_eq!(Foo::new().0, [0; 10]);
}