old_contents: import getFreeBinding from '../utils/getFreeBinding';
  
  /**
   * Convert binary existential operators, e.g. `a ? b` into `if` expressions
   * using unary existential operators, e.g. `if a? then a else b`.
   *
   * @param {Object} node
   * @param {MagicString} patcher
   */
  export default function preprocessBinaryExistentialOperator(node, patcher) {
    if (node.type === 'ExistsOp') {
      // e.g. `if a? then a else b`
      //       ^^^
      patcher.insert(node.range[0], 'if ');
  
      if (node.left.type === 'Identifier') {
        // e.g. `a ? b` -> `if a? then a else b`
        //        ^^^           ^^^^^^^^^^^^^^
        patcher.replace(node.range[0], node.range[1], `${node.left.raw}? then ${node.left.raw} else ${node.right.raw}`);
      } else {
        let tmp = getFreeBinding(node.scope);
        // e.g. `@a ? @b` -> `if (ref = @a)? then ref else @b`
        //       ^^^^^           ^^^^^^^^^^^^^^^^^^^^^^^^^^
        patcher.replace(node.range[0], node.range[1], `(${tmp} = ${node.left.raw})? then ${tmp} else ${node.right.raw}`);
      }
  
      return true;
    }
  }
  
new_contents: import getFreeBinding from '../utils/getFreeBinding';
  
  /**
   * Convert binary existential operators, e.g. `a ? b` into `if` expressions
   * using unary existential operators, e.g. `if a? then a else b`.
   *
   * @param {Object} node
   * @param {MagicString} patcher
   */
  export default function preprocessBinaryExistentialOperator(node, patcher) {
    if (node.type === 'ExistsOp') {
      // e.g. `if a? then a else b`
      //       ^^^
      patcher.insert(node.range[0], 'if ');
  
      if (node.left.type === 'Identifier') {
        // e.g. `a ? b` -> `if a? then a else b`
        //       ^^^^^         ^^^^^^^^^^^^^^^^
        patcher.replace(node.range[0], node.range[1], `${node.left.raw}? then ${node.left.raw} else ${node.right.raw}`);
      } else {
        let tmp = getFreeBinding(node.scope);
        // e.g. `@a ? @b` -> `if (ref = @a)? then ref else @b`
        //       ^^^^^^^         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        patcher.replace(node.range[0], node.range[1], `(${tmp} = ${node.left.raw})? then ${tmp} else ${node.right.raw}`);
      }
  
      return true;
    }
  }
  
subject: Update the comment ranges to reflect the new replacements.