I'm using SDK 12.3.0 with nRF51 in SEGGER ES.
I stumped upon NRF_LOG_ERROR problems. Digging it down i needed to find NRF_LOG_INIT.
It was defined in nrf_log_ctrl.h like that:
#define NRF_LOG_INIT(timestamp_func) NRF_LOG_INTERNAL_INIT(timestamp_func)
So I couldn't search it further using "Go to definitions". I searched through files and find in nrf_log_ctrl_internal.h
#define NRF_LOG_INTERNAL_INIT(timestamp_func) \
nrf_log_init(timestamp_func)
So basically all it does: goes from small letters to capital in nrf_log_init() and obscures function declaration from search.