A few hundred of these after the recent objshrink JM merge:
js/src/jsscope.h(511) : warning C4309: 'initializing' : truncation of constant value
js/src/jsscope.h(511) : warning C4369: 'FIXED_SLOTS_MASK' : enumerator value '-134217728' cannot be represented as 'unsigned int', value is '4160749568'
Line was last touched by https://hg.mozilla.org/mozilla-central/rev/ba69a907d9a4
(Pre-emptive marking resolved fixed, since that cset is marked no bug, so this won't end up being closed on merge otherwise).