A value was moved whose size was not known at compile time.
Erroneous code example:
#![feature(box_syntax)] fn main() { let array: &[isize] = &[1, 2, 3]; let _x: Box<[isize]> = box *array; // error: cannot move a value of type [isize]: the size of [isize] cannot // be statically determined }
In Rust, you can only move a value when its size is known at compile time.
To work around this restriction, consider “hiding” the value behind a reference: either &x
or &mut x
. Since a reference has a fixed size, this lets you move it around as usual. Example:
#![feature(box_syntax)] fn main() { let array: &[isize] = &[1, 2, 3]; let _x: Box<&[isize]> = box array; // ok! }