error[E0435]: attempt to use a non-constant value in a constant --> $DIR/issue-44239.rs:8:26 | LL | let n: usize = 0; | ----- help: consider using `const` instead of `let`: `const n` ... LL | const N: usize = n; | ^ non-constant value error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0435`.