[Bug Report]: typeof sourcemap passed to loader is string, expect object

[claneo]

System Info

System: OS: Linux 5.4 Debian GNU/Linux 11 (bullseye) 11 (bullseye) CPU: (8) x64 Intel(R) Xeon(R) Platinum 8260 CPU @ 2.40GHz Memory: 7.01 GB / 15.40 GB Container: Yes Shell: 5.8 - /usr/bin/zsh Binaries: Node: 18.14.2 - ~/.nvm/versions/node/v18.14.2/bin/node npm: 9.5.0 - ~/.nvm/versions/node/v18.14.2/bin/npm npmPackages: @rspack/cli: ^0.1.0 => 0.1.0

Details

When I try to use babel-loader after another loader, it reports an error:

Error: .inputSourceMap must be a boolean, object, or undefined

Reproduce link

No response

Reproduce Steps

// rspack.config.js
/** @return {import('@rspack/cli').Configuration} */
module.exports = () => {
  return {
    module: {
      rules: [
        {
          test: /\.js$/,
          use: './loader-b',
        },
        {
          test: /\.js$/,
          use: './loader-a',
        },
      ],
    },
  };
};

// loader-a.js
module.exports = function (source, map, meta) {
  this.callback(null, source, {}, meta);
  return;
};

// loader-b.js
module.exports = function (source, map, meta) {
  console.log(typeof map); // <------ it prints `object` in webpack, but got `string` in rspack
  this.callback(null, source, map, meta);
  return;
};