Code Inspection: Heuristically unreachable case due to integer analysis

This inspection reports cases of switch statements that will never be executed according to the results of integer value analysis. The inspection only works if Analyze integer arithmetic is enabled on the Editor | Inspection Settings page of JetBrains Rider settings Control+Alt+S.

Here is an example of annotating the method parameter with [NonNegativeValueAttribute] to refine the analysis within the method body. Knowing that the parameter is non-negative, JetBrains Rider can report redundant cases:

void TestSwitch([NonNegativeValue] int input)
{
    int newValue;
    switch (input)
    {
        case 0:
            newValue = 1;
            break;
        case -1:  // Case is heuristically unavailable
            newValue = 0;
            break;
        default:
            newValue = input;
            break;
    }
}

Last modified: 21 December 2021