src/test/ui/issues/issue-39559-2.rs

trait Dim {
    fn dim() -> usize;
}

enum Dim3 {}

impl Dim for Dim3 {
    fn dim() -> usize {
        3
    }
}

fn main() {
    let array: [usize; Dim3::dim()]
    //~^ ERROR E0015
        = [0; Dim3::dim()];
        //~^ ERROR E0015
}