Sir,I want to make a new PCB ,and want add a Row in REDOX-w（Row5）. Can you tell me which part of the RECEIVER`s qmk should be modified？

[latincompass]

I have compile completely in 51822,but the receiver`s QMK seems ERROR.like this:

Compiling: keyboards/redox_w/matrix.c keyboards/redox_w/matrix.c: In function 'matrix_scan':
keyboards/redox_w/matrix.c:123:45: error: iteration 5 invokes undefined behavior [-Werror=aggressive-loop-optimizations]
matrix[i] = (uint16_t) uart_data[i2] | (uint16_t) uart_data[i2+1] << 7;
~~~~~~~~~^~~~~
keyboards/redox_w/matrix.c:122:9: note: within this loop
for (uint8_t i = 0; i < MATRIX_ROWS+1; i++) {
^~~
cc1.exe: all warnings being treated as errors

The file config.h row 6 col 14
The file redox_w.c redox_w.h is ok to row 6
Thanks!