Ran into this while working on Bug 770309. A recent change to jsinterp.cpp's handling of JSOP_NEW breaks UseNewType's pattern matching. It modified the current context to refer to the callee before calling UseNewType, when UseNewType operates on the caller. Fix should be quick, some small re-ordering of code.
Created attachment 642051 [details] [diff] [review] Patch.
This landed on inbound as: https://hg.mozilla.org/integration/mozilla-inbound/rev/8837ebfb3045 However the bug number was incorrect. Please can you backout and reland with the correct # so as to make hg blame clearer. Thanks :-)
Thanks for the heads up :) Reverted, fixed, and pushed: https://hg.mozilla.org/integration/mozilla-inbound/rev/3b2bad6c343b