ASSERTION FAILED: m_frame->view() (/Users/eseidel/Projects/CommitQueue/WebCore/loader/FrameLoader.cpp:3103 void WebCore::FrameLoader::transitionToCommitted(WTF::PassRefPtr<WebCore::CachedPage>)) This appears to be timing sensitive. You may need to reload the page more than once to see it. run-safari --debug frame_assert.html reproduces for me though.
It looks like my Debug build was old. Rebuilding to make sure that this happens in tip of tree sources. I'll get an updated line number when that finishes.
Nevermind this seems to be gone now.