Calling the ! or ~ prefix operator twice does nothing: the second invocation undoes the first. Such mistakes are typically caused by accidentally double-tapping the key in question without noticing.

Either this is a bug, if the operator was actually meant to be called once, or misleading if done on purpose.

Noncompliant Code Example

int v1 = 0;
bool v2 = false;

var v3 = !!v1; // Noncompliant
var v4 = ~~v2; // Noncompliant

Compliant Solution

int v1 = 0;
bool v2 = false;

var v3 = !v1;
var v4 = ~v2;