When using a range-based for-loop, there is a correct declaration for the element variable, but there are no uses for the range passed to the loop; it's not highlighted at all in the editor.

void test() {
    std::vector<int> myVector = {1,2,3,4,5};
    for (int x : myVector) { // myVector is shown in black with no tooltip
        x+=1;
    }
}