FP truncLongCastAssignment

[Marcin Pytel]

I'm using cppcheck 2.18.0

Here is code:

// scanf and printf are just to get rid of unused and uninitialized variable
int main()
{
        uint32_t a;
        scanf("%u", &a);
        uint32_t i = a, j = a;
        uint64_t k = i * j;
        printf("%lu", k);
}

When running cppcheck --enable=style I have error:

style: int result is assigned to long variable. If the variable is long to avoid loss of information, then you have loss of information. [truncLongCastAssignment]

uint64_t k = i * j;

There's no issue when I remove the scanf and assign some number to the a variable e.g. uint32_t a = 5;

[CHR]

That seems to be a true positive. The multiplication is done using 32 bits, and the result is assigned to a 64 bit value. In case of a = 5, cppcheck knows that no overflow can occur.