Run css/css-values/minmax-angle-computed.html WPT test in the minibrowser with a Debug build. Try to set a breakpoint on the first test_angle_equals call. (Should be `test_angle_equals('min(1deg)', '1deg');`) Reload the page and the breakpoint will now be greyed out. This doesn't happen in shipping Safari. For reference I built against r267362.
<rdar://problem/69333373>
*** This bug has been marked as a duplicate of bug 217862 ***