Mixup in tagged template literals in exported function

[cauthmann]

Hello,

swc+webpack got our compilation times for debug builds down to ~3s from ~7s, which makes hitting F5 after a change much less frustrating! Thanks!

However, it breaks our use of tagged template literals for i18n. Setting target: "es2019" avoids the broken transformation, but there's still a bug somewhere.

cat test.js:

export function foo() {
	console.log(i18n`Hello World`);
	console.log(i18n`Nobody will ever see this.`);
}

npx swc --no-swcrc test.js

function _taggedTemplateLiteral(strings, raw) {
    if (!raw) {
        raw = strings.slice(0);
    }
    return Object.freeze(Object.defineProperties(strings, {
        raw: {
            value: Object.freeze(raw)
        }
    }));
}
function _templateObject() {
    var data = _taggedTemplateLiteral([
        'Hello World'
    ]);
    _templateObject = function _templateObject() {
        return data;
    };
    return data;
}
function _templateObject1() {
    var data = _taggedTemplateLiteral([
        'Nobody will ever see this.'
    ]);
    _templateObject1 = function _templateObject1() {
        return data;
    };
    return data;
}
export function foo() {
    console.log(i18n(_templateObject()));
    console.log(i18n(_templateObject()));
}

Note the last line, where it should use _templateObject1(), but uses _templateObject() again. Consequently, if we insert an implementation of i18n() and call foo(), running the transformed function says Hello World twice.

Note that the bug only appears in exported functions.

[kdy1]

I think the problem is export function. Can you try removing export from it?

Btw, I need to find a better test suite.

[cauthmann]

Yes, the bug only appears in exported functions. When mixing exported functions with non-exported ones, only the exported ones break. Removing the export fixes it.

[swc-bot]

This closed issue has been automatically locked because it had no new activity for a month. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.