[Bug]: lost default params value when compressing

[fi3ework]

System Info

Using 1.3.10 version of Rspack.

System:
OS: macOS 15.0.1
CPU: (14) arm64 Apple M3 Max
Memory: 283.58 MB / 36.00 GB
Shell: 5.9 - /bin/zsh
Binaries:
Node: 23.7.0 - ~/Library/Caches/fnm_multishells/74108_1748231646341/bin/node
npm: 10.9.2 - ~/Library/Caches/fnm_multishells/74108_1748231646341/bin/npm
pnpm: 10.8.1 - ~/Library/Caches/fnm_multishells/73593_1748231644604/bin/pnpm
bun: 1.2.9 - ~/.bun/bin/bun
Browsers:
Chrome: 136.0.7103.114
Safari: 18.0.1

Details

When compress is enabled, there will an undefined lng variable which will cause a runtime error.

new class {
}().init({
    resources: {
        'zh-CN': {
            translation: {
                _created_in: "\uFF0C\u521B\u5EFA\u4E8E"
            }
        },
        'en-US': {
            translation: {
                _created_in: ', created'
            }
        }
    },
    lng
});
let a = 1;
export { a };

Reproduce link

https://github.com/fi3ework-reproduction/rspack-compress-bug

Reproduce Steps

1. pnpm i
2. check dist-difference or see rslib.config.ts to see toggle the compress field.

[fi3ework]

Reproduced in SWC playground in 1.11.24 (link), while fixed in 1.11.29 (link), we could close this issue after SWC bumped.