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

[source,php]
----
$a = 0;
$b = false;

$c = !!$a; // Noncompliant
$d = ~~$b; // Noncompliant
----

== Compliant Solution

[source,php]
----
$a = 0;
$b = false;

$c = !$a; // Compliant
$d = ~$b; // Compliant
----

ifdef::env-github,rspecator-view[]

'''
== Implementation Specification
(visible only on this page)

include::../message.adoc[]

'''
== Comments And Links
(visible only on this page)

include::../comments-and-links.adoc[]
endif::env-github,rspecator-view[]