V537. Consider reviewing the correctness of 'X' item's usage

14.06.2012

The analyzer detected a potential misprint in code. This rule tries to diagnose an error of the following type using the heuristic method:

int x = static_cast<int>(GetX()) * n;
int y = static_cast<int>(GetX()) * n;

In the second line, the GetX() function is used instead of GetY(). This is the correct code:

int x = static_cast<int>(GetX()) * n;
int y = static_cast<int>(GetY()) * n;

To detect this suspicious fragment, the analyzer followed this logic: we have a line containing a name that includes the "X" fragment. Beside it, there is a line that has an antipode name with "Y". But this second line has "X" as well. Since this condition and some other conditions hold, the construct must be reviewed by the programmer. This code would not be considered dangerous if, for instance, there were no variables "x" and "y" to the left. This is a code sample the analyzer ignores:

array[0] = GetX() / 2;
array[1] = GetX() / 2;

Unfortunately, this rule often produces false alarms since the analyzer does not know how the program is organized and what the code's purpose is. This is a sample of a false alarm:

halfWidth -= borderWidth + 2;
halfHeight -= borderWidth + 2;

The analyzer supposed that the second line must be presented by a different expression, for instance, "halfHeight -= borderHeight + 2". But actually there is no error here. The border's size is equal in both vertical and horizontal positions. There is just no borderHeight constant. However, such high-level abstractions are not clear to the analyzer. To suppress this warning, you may type the "//-V537" comment into the code.

You can look at examples of errors from real projects which were detected by this diagnostic message.