Maximum voltage on PIC I/O line

Hi all
I wanted to ask what is the maximum negative and positive voltage i can apply to the PIC I/O line when configured as an input.
I think it is VDD + 0.3V and VSS-0.3V

The PIC has input protection diodes. So my question is can i go beyond these limits? Say i had 3.6V and -0.6V. Would the diodes not conduct and prevent damage to the PIC. I presume that there will also be a current limit of the diode that i cant exceed? I am using a PIC16F1938.

Thanks in advance