Code inspection: Heuristically unreachable code

Among other things, JetBrains Rider analyzes values and nullability and integer arithmetics, and uses the results of these analyses to identify code that never executes.

In the example below, this inspection reports Console.WriteLine("Error"); as unreachable, because the program can only enter the foreach loop if the list is not null. Therefore, the condition list == null will always be false inside this loop, and as a result, any code within this condition will never execute.

        
class Sample
{
    void Test(IEnumerable<string> list)
    {
        foreach (var str in list)
        {
            if (list == null)
                Console.WriteLine("Error"); // Code is unreachable
        }
    }
}

    

Last modified: 27 May 2024