React.renderComponent() tries to update components without checking their constructor type

[petehunt]

See this jsfiddle: http://jsfiddle.net/j7skc/1/
Reported here: https://groups.google.com/forum/?fromgroups#!topic/reactjs/tCFACnPMZ6Q

Looks like we aren't checking the constructor type to figure out that we should unmount rather than receive new props. This may be fixed in master already (haven't checked); @yungsters or @jordow can you take a look (and add a test)?

[zpao]

I think this got fixed by 100af48, but haven't confirmed

[zpao]

And confirmed that it's working in master.