Syntax checking to auto-detect PostCSS in <style>

[privatenumber]

• [x] I have searched through existing issues

Feature Request

I'm getting syntax errors in the <style> block on nested CSS rules and it seems the expected solution here is to add lang="postcss".

However, this is confusing because vue-loader docs say:

There's no need to specify lang="postcss" on a style block if there is a PostCSS config file in your project.

• vue-loader v14 docs

I'd like to request that Vetur implicitly determines whether the syntax is PostCSS, by detecting:

• if there's a PostCSS config file: postcss.config.js, .postcssrc.js, etc.
• which files postcss-loader is applied to

[yoyo930021]

which files postcss-loader is applied to

This can't be done because vetur has no way of knowing your webpack config.

if there's a PostCSS config file: postcss.config.js, .postcssrc.js, etc.

This may be possible. Welcome a PR.

[blowsie]

For what its worth, adding lang="postcss" breaks the deep selectors in storybook-vue