A cast to an unsized type was attempted.
Erroneous code example:
let x = &[1_usize, 2] as [usize]; // error: cast to unsized type: `&[usize; 2]` // as `[usize]`
In Rust, some types don't have a known size at compile-time. For example, in a slice type like [u32]
, the number of elements is not known at compile-time and hence the overall size cannot be computed. As a result, such types can only be manipulated through a reference (e.g., &T
or &mut T
) or other pointer-type (e.g., Box
or Rc
). Try casting to a reference instead:
let x = &[1_usize, 2] as &[usize]; // ok!