When constraints have not been applied to restrict a generic type parameter to be a reference type, then a value type, such as a ``++struct++``, could also be passed. In such cases, comparing the type parameter to ``++null++`` would always be false, because a ``++struct++`` can be empty, but never ``++null++``. If a value type is truly what's expected, then the comparison should use ``++default()++``. If it's not, then constraints should be added so that no value type can be passed.

== Noncompliant Code Example

----
private bool IsDefault<T>(T value) 
{
  if (value == null) // Noncompliant
  {
    // ...
  }
  // ...
}
----

== Compliant Solution

----
private bool IsDefault<T>(T value) 
{
  if(object.Equals(value, default(T)))
  {
    // ...
  }
  // ...
}
----
or

----
private bool IsDefault<T>(T value) where T : class
{
  if (value == null) 
  {
    // ...
  }
  // ...
}
----
