Many people don't know the Element.querySelector() and Element.querySelectorAll() behaves differently than most common JavaScript DOM libraries, details.

Got the idea here

Fail

const inner = element.querySelectorAll('.outer .inner');

Pass

const inner = document.querySelectorAll('.outer .inner');

const inner = element.querySelectorAll(':scope .outer .inner');

I'm not sure about these, they are never going to get wrong result.

const inner = element.querySelectorAll('.a');

const inner = element.querySelectorAll('.a + .b');

Should we enforce them consistently, or only check descendant combinator and child combinator?