Clang correctly identifies this problem: /home/njn/moz/mi6/js/src/ion/IonBuilder.cpp:4719:9: warning: variable 'gotLambda' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] if (calleeTypes) { ^~~~~~~~~~~ /home/njn/moz/mi6/js/src/ion/IonBuilder.cpp:4723:18: note: uninitialized use occurs here JS_ASSERT_IF(gotLambda, originals.length() <= 1); ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ./dist/include/js/Utility.h:43:49: note: expanded from macro 'JS_ASSERT_IF' #define JS_ASSERT_IF(cond, expr) MOZ_ASSERT_IF(cond, expr) ^ ./dist/include/mozilla/Assertions.h:305:12: note: expanded from macro 'MOZ_ASSERT_IF' if (cond) \ ^~~~ /home/njn/moz/mi6/js/src/ion/IonBuilder.cpp:4719:5: note: remove the 'if' if its condition is always true if (calleeTypes) { ^~~~~~~~~~~~~~~~~ /home/njn/moz/mi6/js/src/ion/IonBuilder.cpp:4717:19: note: initialize the variable 'gotLambda' to silence this warning bool gotLambda; ^ = false

I don't anything about this code, but this fix looks reasonable.

Comment on attachment 763303 [details] [diff] [review] Fix uninitialized |gotLambda| in ion/IonBuilder.cpp Review of attachment 763303 [details] [diff] [review]: ----------------------------------------------------------------- Thanks Nicholas.