So far all of available tests for interpolation of CSS variables have been looking at whether the CSS variable itself is correctly interpolated. In practice, it's important to test that an interpolated value is picked up by other standard CSS properties that use that CSS variable.
Pull request: https://github.com/WebKit/WebKit/pull/7692
Submitted web-platform-tests pull request: https://github.com/web-platform-tests/wpt/pull/37527
Committed 257924@main (fa664e0f3367): <https://commits.webkit.org/257924@main> Reviewed commits have been landed. Closing PR #7692 and removing active labels.
<rdar://problem/103405255>