compilre does not complain of "," instead of ";"

Hi I have the following code static bit cc_0 = 0;
...... if ((!CC_GDO_0 && cc_0) == 0) return 0;

cc_0 = 0, // here I have a , instead of ;

temp = SpiReadStatus(CCxxx0_MARCSTATE);
.....
I am surprise that the compiler does not generate or warn me of the comma error?

I have version 87.08 of C51.