misra 12.2 false negative?

[Richard Smith]

I discovered some expressions in our code earlier today that I expected to be triggering 12.2 but they don't seem to make it happen. I've duplicated on HEAD with the following small snipit.

Can someone verify this is not working?

m1.c is the following:

unsigned char buff_8[2];

uint32_t shift_u8t_8(void)
{
    unsigned char u8_val = buff_8[0] << 8u;

    return (uint32_t)(buff_8[0] << 8u)
}

/home/src/cppcheck.git/addons/test$ 
/home/src/cppcheck.git/addons/test$ ../../build/bin/cppcheck --addon=misra.py ./misra/m1.c
Checking misra/m1.c ...
/home/src/cppcheck.git/addons/test$ 

[Jean-Loic MARTIN]

Hi Richard,

You are right, this is not working for unsigned char array.
This is ok for unsigned char and signed char.
It should generates an error in your case (and in the case below).

char cFunc(unsigned char ucVar)
{
    unsigned char ucToto[2];
    ucToto[1] = ucVar;
    ucToto[0] = (unsigned char)(ucToto[1] << 8u);
    return ucToto[0];
}

I think the problem comes from array variables. But i'm not able to correct it i'm not a python programmer.

[Jean-Loic MARTIN]

Up of this topic.
Has someone opened a ticket for that problem ?

[Daniel Marjamäki]

good that you reminded me. Now I have created a ticket:
https://trac.cppcheck.net/ticket/10113

[Jean-Loic MARTIN]

thank you Daniel !