[PHP 8.3] Check variance of class constants (#4183)

Author: alexandre-daubois

language/oop5/constants.xml

@@ -120,10 +120,42 @@ Fatal error: Uncaught Error: Cannot access private const Foo::BAZ in …
    As of PHP 7.1.0 visibility modifiers are allowed for class constants.
   </para>
  </note>
+ <example>
+  <title>Class constant visibility variance check, as of PHP 8.3.0</title>
+  <programlisting role="php">
+<![CDATA[
+<?php
+
+interface MyInterface
+{
+    public const VALUE = 42;
+}
+
+class MyClass implements MyInterface
+{
+    protected const VALUE = 42;
+}
+?>
+]]>
+  </programlisting>
+  &example.outputs.83;
+  <screen>
+<![CDATA[
+Fatal error: Access level to MyClass::VALUE must be public (as in interface MyInterface) …
+]]>
+  </screen>
+ </example>
+ <note>
+  <simpara>
+   As of PHP 8.3.0 visibility variance is checked more strictly.
+   Prior to this version, the visibility of a class constant could be different
+   from the visibility of the constant in the implemented interface.
+  </simpara>
+ </note>
  <example>
   <title>Fetch class constant syntax, as of PHP 8.3.0</title>
   <programlisting role="php">
-   <![CDATA[
+<![CDATA[
 <?php
 class Foo {
     public const BAR = 'bar';