error[E0435]: attempt to use a non-constant value in a constant --> $DIR/issue-91560.rs:10:19 | LL | let mut length: usize = 2; | -------------- help: consider using `const` instead of `let`: `const length` LL | LL | let arr = [0; length]; | ^^^^^^ non-constant value error[E0435]: attempt to use a non-constant value in a constant --> $DIR/issue-91560.rs:17:19 | LL | let length: usize = 2; | ------------ help: consider using `const` instead of `let`: `const length` LL | LL | let arr = [0; length]; | ^^^^^^ non-constant value error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0435`.