Potential FP: containerOutOfBounds

[Muhammad Javed]

I have the following scenario:

// test.cpp
#include <array>
#include <cstddef>

template<size_t Size>
struct Test
{
    Test(std::array<int, Size> aArray)
    {
        if (Size > 2)
        {
            for(int i = mArray.size() - 2; i >= 0; --i)
            {
                mArray[i] = mArray[i + 1] * aArray[i + 1];
            }
        }
    }
    std::array<int, Size - 1> mArray;
};

Test<1> t({0});

Cppcheck gives the following report about this code:

Checking test.cpp ...
test.cpp:14:51: error: Out of bounds access in 'aArray[i+1]', if 'aArray' size is 1 and 'i+1' is greater or equal to 1 [containerOutOfBounds]
                mArray[i] = mArray[i + 1] * aArray[i + 1];
                                                  ^
test.cpp:12:46: note: Assuming that condition 'i>=0' is not redundant
            for(int i = mArray.size() - 2; i >= 0; --i)
                                             ^
test.cpp:14:51: note: Access out of bounds
                mArray[i] = mArray[i + 1] * aArray[i + 1];
                                                  ^

Cppcheck says that if aArray's size is 1 then the access aArray[i+1] would be out of bounds. However, due to the if condition, that access would never occur in such a scenario.
Thanks.

[CHR]

Thanks for reporting, I have created this ticket: https://trac.cppcheck.net/ticket/11447

[Muhammad Javed]

Thank you so much!