chromium/third_party/blink/web_tests/fast/block/float/negative-margin-clear.html

<style>
#inner {
    height: 350px;
    margin-top: -350px;
    clear: both;
}
#outer {
    border: 4px solid red;
}
</style>

<div id="outer">
<div id="inner">
</div>
</div>