"Condition is always true" false positive

[Nikita Leontiev]

Below "Condition is always true" false positive occurs since cppcheck 2.10:

#include <inttypes.h>
#include <vector>

void func(const std::vector <uint8_t> & bytes)
{
    size_t size = bytes.size();
    size_t count = (size > 100)?100:size;
    if (count < 100)
    {
    }
}

int main()
{
    return 0;
}

[test.cpp:8]: (style) Condition 'count<100' is always true

[CHR]

Thanks for reporting, I think this is covered by https://trac.cppcheck.net/ticket/11437

[Tobias Mark]

Here another false-positive (never seen this with 2.9.) that's maybe related:

int func(unsigned char c) {
    if(c>127 && c<160) {
        int x = 0;
        if(c == 128) {
            x = 1;
        }
        if(x != 0) {
            return 1;
        }
    }
    return 0;
}

test.c:18:7: note: Condition 'x!=0' is always false
 if(x != 0) {

When removing the c<160 condition the error goes away.

[CHR]

That seems to be a different issue, ticket: https://trac.cppcheck.net/ticket/11532

[Andrew C Aitchison]

Can you confirm that 2.9 does not give this error ?
My test suggest that cppcheck --enable=style gives this problem at least at far back as 2.6 for Tobias's code with c<160

[Tobias Mark]

I can't confirm this.
It may be possible that some internalASTError (that are no fixed) prevented this error for me with 2.9.