false-positive: negativeIndex with multiple layers of function calls, arrays and ternary operators

[Jens]

I already mentioned this false positive in the IRC, but I dropped out, so I do not know if there were any responses, because I can't see the history.

#include <stdio.h>
#include <stdlib.h>

#define maxIndex 4
#define answerToAll 42

int array[maxIndex];
int otherArray[1] = {answerToAll};
int otherArgument = 0;

int func(int val) {
  return 0;
}

int main(int argc, char **argv) {
  int index;
  if (scanf("index %3i %3i",&index, &otherArgument)==2) 
    if(index<0 || index>maxIndex) { printf("err\n"); exit(1); }
    else {
      printf("%d\n", (otherArgument <= 0) ? -1 : otherArray[func(index ? array[index - 1] : 0)]);
    }

  return 0;
}

cppcheck (version 1.90) output:

> cppcheck --enable=all .
Checking test.c ...
test.c:20:79: warning: Either the condition 'index<0' is redundant or the array 'array[4]' is accessed at index -1, which is out of bounds. [negativeIndex]
      printf("%d\n", (otherArgument <= 0) ? -1 : otherArray[func(index ? array[index - 1] : 0)]);
                                                                              ^
test.c:18:13: note: Assuming that condition 'index<0' is not redundant
    if(index<0 || index>maxIndex) { printf("err\n"); exit(1); }
            ^
test.c:20:79: note: Negative array index
      printf("%d\n", (otherArgument <= 0) ? -1 : otherArray[func(index ? array[index - 1] : 0)]);
                                                                              ^
nofile:0:0: information: Cppcheck cannot find all the include files (use --check-config for details) [missingIncludeSystem]

[Daniel Marjamäki]

I believe this is fixed. I can reproduce the warning with cppcheck-1.90 but latest cppcheck is silent.