False positive for rule arrayIndexOutOfBoundsCond in cppcheck 2.9

[Mark Spencer]

Hello and thank you for producing such a fantastic open source product! I have, however, discovered the following issue. Consider the following snippet:

#define XFD_MAX_CARDS 16
typedef struct {
    int *cards[XFD_MAX_CARDS];
} xfd_gauge_carddeck;

int iterate_cards(xfd_gauge_carddeck *carddeck, int all, int sticky)
{
    int ret = 0;
    /* Note: Does not generate false positive if you put XFD_MAX_CARDS in place of (sizeof(carddeck->cards)/sizeof(carddeck->cards[0])) */
    if (!all && (sticky > -1) && (sticky < (sizeof(carddeck->cards)/sizeof(carddeck->cards[0])))) {
        if (carddeck->cards[sticky])
            printf("value is %d\n", *carddeck->cards[sticky]);
    }

    return ret;
}

The above snippet kicks out an arrayIndexOutOfBoundsCond in cppcheck 2.9. Notably, using XFD_MAX_CARDS in place of the sizeof() math to generate the top end value clears the error.

[Mark Spencer]

For clarity, please see the following command line and results

[xfs]$ cppcheck --enable=all test.c
Checking test.c ...
test.c:11:22: warning: Either the condition 'sticky>-1' is redundant or the array 'carddeck->cards[16]' is accessed at index 16, which is out of bounds. [arrayIndexOutOfBoundsCond]
  if (carddeck->cards[sticky])
                     ^
test.c:10:22: note: Assuming that condition 'sticky>-1' is not redundant
 if (!all && (sticky > -1) && (sticky < (sizeof(carddeck->cards)/sizeof(carddeck->cards[0])))) {
                     ^
test.c:11:22: note: Array index out of bounds
  if (carddeck->cards[sticky])
                     ^
test.c:6:0: style: The function 'iterate_cards' is never used. [unusedFunction]

^
[xfs]$ 

[CHR]

No repro with head, so maybe this is already fixed.