Fix false negatives for custom properties within var() in custom-property-pattern

[kawaguchi1102]

Which issue, if any, is this issue related to?

Closes #3655

Is there anything in the PR that needs further explanation?

The following problem has not been solved.
You will need to create another isuue.

The following is a false positive (as it's invalid syntax) and should be ignored by this rule. We > can either squish that bug within this issue or create a separate issue for it.
--invalid-custom-property-variable: #fff;

#3655 (comment)

[ybiquitous]

@kawaguchi1102 Thank you so much for creating the pull request! And, sorry for the late response.

I've left some trivial suggestions, but this PR sounds almost good to me. 👍🏼

[ybiquitous]

One more suggestion. Please rebase or merge the main branch to fix the failed CI jobs for Windows. (see #5874)

[jeddy3]

Thanks for the pull request. Looking good.

Let's also reject tests for:

• :root { --foo-color: #f00; } a { color: 'VAR(--boo-color)); }
• :root { --foo-color: #f00; } a { color: 'var(--boo-color), var(--boo-sub-color)); }

The latter should produce two warnings, like so.

[kawaguchi1102]

@ybiquitous @jeddy3 Thanks for the review.

I have fixed them, please review again.

[jeddy3]

LGTM, thank you!

[ybiquitous]

@kawaguchi1102 Thanks, LGTM 👍🏼

[jeddy3]

• Fixed: custom-property-pattern false negatives for custom properties within var() (#5867).