== Why is this an issue?

include::../description.adoc[]

=== Noncompliant code example

[source,csharp]
----
var a = double.NaN;

if (a == double.NaN) // Noncompliant; always false
{
  Console.WriteLine("a is not a number");  // this is dead code
}
if (a != double.NaN)  // Noncompliant; always true
{
  Console.WriteLine("a is not NaN"); // this statement is not necessarily true
}
----

=== Compliant solution

[source,csharp]
----
if (double.IsNaN(a)) 
{
  console.log("a is not a number");
}
----


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

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

=== Message

Use double.IsNaN() instead.


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

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