WiredTiger uses this idiom in a few dozen places:

did_work = yield == 0;

In this case (taken from __log_wrlsn_server), we are setting did_work to true if yield is zero.

But it is easy to misread this as an assignment of zero to both did_work and yield. This is an easy point of confusion because we frequently initialize multiple variables on the same line in a similar manner. 

To help avoid this type of misreading, we should change this usage to:

did_work = (yield == 0);