Having #13756 and #16239 merged cause GCC warning:
$ gcc --version
gcc (Ubuntu 7.4.0-1ubuntu1~18.04.1) 7.4.0
...
$ make -j 4 > /dev/null
wallet/wallet.cpp: In member function ‘CWallet::Balance CWallet::GetBalance(int, bool) const’:
wallet/wallet.cpp:2269:45: warning: enumeral and non-enumeral type in conditional expression [-Wextra]
isminefilter reuse_filter = avoid_reuse ? 0 : ISMINE_USED;
~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
Fixed with this PR.