From 871df69f47f578c79cad7889f7e27d4b737baf4d Mon Sep 17 00:00:00 2001
From: George Peter Banyard <girgias@php.net>
Date: Thu, 18 Feb 2021 16:22:58 +0000
Subject: [PATCH] Explain what consistitutes a more specific type

Closes GH-457
---
 language/oop5/variance.xml | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/language/oop5/variance.xml b/language/oop5/variance.xml
index 9890ef9332..1e6e0f2534 100644
--- a/language/oop5/variance.xml
+++ b/language/oop5/variance.xml
@@ -13,6 +13,28 @@
   of its parent's method. Whereas, contravariance allows a parameter type to be less 
   specific in a child method, than that of its parent.
  </para>
+ <para>
+  A type declaration is considered more specific in the following case:
+  <itemizedlist>
+   <listitem>
+    <simpara>
+     A type is removed from a union type
+    </simpara>
+   </listitem>
+   <listitem>
+    <simpara>
+     A class type is changed to a child class type
+    </simpara>
+   </listitem>
+   <listitem>
+    <simpara>
+     <type>float</type> is changed to <type>int</type>
+    </simpara>
+   </listitem>
+  </itemizedlist>
+
+  A type class is considered less specific if the opposite is true.
+ </para>
 
  <sect2 xml:id="language.oop5.variance.covariance">
   <title>Covariance</title>