error[E0435]: attempt to use a non-constant value in a constant --> $DIR/issue-3668-2.rs:4:27 | LL | static child: isize = x + 1; | ------------ ^ non-constant value | | | help: consider using `let` instead of `static`: `let child` error: aborting due to previous error For more information about this error, try `rustc --explain E0435`.