An array without a fixed length was pattern-matched.
Example of erroneous code:
```compile_fail,E0730
#![feature(const_generics)]
fn is_123<const N: usize>(x: [u32; N]) -> bool {
match x {
[1, 2, 3] => true, // error: cannot pattern-match on an
// array without a fixed length
_ => false
}
}
```
Ensure that the pattern is consistent with the size of the matched
array. Additional elements can be matched with `..`:
```
#![feature(slice_patterns)]
let r = &[1, 2, 3, 4];
match r {
&[a, b, ..] => { // ok!
println!("a={}, b={}", a, b);
}
}
```