Fails on ES6 backtick quotes

[AArnott]

We have this code that vscode-nls-dev rewrites:

public static failedToEnumerateFilesInDir(path: string, errCode: string, errMessage: string): string {
    return localize(
        {
            key: 'Failed.To.Enumerate.Files.In.Dir',
            comment:
            [
                'Error message when failed to enumerate files in a directory.'
            ]
        },
        `Failed to enumerate files in directory '{0}'. Error code={1}, Error message={2}`,
        path,
        errCode,
        errMessage
    );
}

When targeting ES5, all is well. But once we target ES6, the backtick as a quote character is preserved:

static failedToEnumerateFilesInDir(path, errCode, errMessage) {
    return localize({
        key: 'Failed.To.Enumerate.Files.In.Dir',
        comment: [
            'Error message when failed to enumerate files in a directory.'
        ]
    }, `Failed to enumerate files in directory '{0}'. Error code={1}, Error message={2}`, path, errCode, errMessage);
}

This causes vscode-nls-dev to fail during build with this error:

libraryResourceStrings.js(661,11): second argument of a localize call must be a string literal.

For now we workaround it by changing our own use of backtick to single quotes. But that requires much more escaping in our English strings because we use single-quotes inside the localizable string.

Please enable use of backticks.

[seanzer]

+1

[seanzer]

I think another problem is that if I escape the new lines like:

"line one\
line two\
line three"

the \ gets escaped in the output, which means I have to strip them before I render it.