Why is this an issue?

Empty statements, i.e. ;, are usually introduced by mistake, for example because:

• It was meant to be replaced by an actual statement, but this was forgotten.
• There was a typo which lead the semicolon to be doubled, i.e. ;;.

Noncompliant code example

void DoSomething()
{
    ; // Noncompliant - was used as a kind of TODO marker
}

void DoSomethingElse()
{
    Console.WriteLine("Hello, world!");;  // Noncompliant - double ;
    // ...
    // Rarely, they are used on purpose as the body of a loop. It is a bad practice to
    // have side-effects outside of the loop:
    for (int i = 0; i < 3; Console.WriteLine(i), i++); // Noncompliant
    // ...
}

Compliant solution

void DoSomething()
{
}

void DoSomethingElse()
{
    Console.WriteLine("Hello, world!");
    // ...
    for (int i = 0; i < 3; i++)
    {
        Console.WriteLine(i);
     }
    // ...
}