message: Rename an unused eval to _eval
  Summary: The macro made it seem used, but it's not really.
diff: @@ -585,7 +585,7 @@ impl Compiler<'_> {
  }
  Expr::Not(expr) => {
  let expr = self.expr(*expr);
  - expr!(expr, |eval| Value::new_bool(!expr.to_bool()))
  + expr!(expr, |_eval| Value::new_bool(!expr.to_bool()))
  }
  Expr::Minus(expr) => match expr.unpack_int_literal().and_then(i32::checked_neg) {
  None => {
  