== Why is this an issue?

Classes should only hold ``++weak++`` references to delegate fields with ``++class++`` type. Otherwise, the owning class will have a ``++strong++`` reference to its delegate, and vice versa, and the OS won't be able to deallocate either of them..


Note that this only applies to non-computed delegate fields in classes, and not to fields in ``++struct++``s and ``++enum++``s.


=== Noncompliant code example

[source,swift]
----
class MyClass {
  var delegate: ConventionDelegate?  // Noncompliant
}
----


=== Compliant solution

[source,swift]
----
class MyClass {
  weak var delegate: ConventionDelegate?
}
----


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

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

=== Message

Mark this variable as "weak" to avoid reference cycles.


=== Highlighting

variable declaration


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

=== on 5 Sep 2017, 17:57:58 Elena Vilchik wrote:
Problem of reference cycles is an important one in Swift (see this https://developer.apple.com/library/content/documentation/Swift/Conceptual/Swift_Programming_Language/AutomaticReferenceCounting.html[doc]), but in order to track this pattern we need a semantic information, which we don't have.

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