PHP 8.2 | PSR12/NullableTypeDeclaration: allow for nullable true/false

As of PHP 8.2, `true`, `false` and `null` will be allowed as stand-alone types.
The `true` and the `false` types are allowed to be nullable, the `null` type is not (but that's not the concern of the sniff).
Also see: https://3v4l.org/ZpfID

This adjusts the sniff to take these new types into account.

Includes unit tests.

Refs:
* https://wiki.php.net/rfc/null-false-standalone-types
* https://wiki.php.net/rfc/true-type

src/Standards/PSR12/Sniffs/Functions/NullableTypeDeclarationSniff.php

@@ -27,6 +27,9 @@ class NullableTypeDeclarationSniff implements Sniff
         T_SELF         => true,
         T_PARENT       => true,
         T_STATIC       => true,
+        T_NULL         => true,
+        T_FALSE        => true,
+        T_TRUE         => true,
     ];
 
 

src/Standards/PSR12/Tests/Functions/NullableTypeDeclarationUnitTest.inc

@@ -85,3 +85,11 @@ class testInstanceOf() {
 
 // PHP 8.0: static return type.
 function testStatic() : ? static {}
+
+// PHP 8.2: nullable true/false.
+function fooG(): ? true {}
+function fooH(): ?
+     false {}
+
+// Fatal error: null cannot be marked as nullable, but that's not the concern of this sniff.
+function fooI(): ? null {}

src/Standards/PSR12/Tests/Functions/NullableTypeDeclarationUnitTest.inc.fixed

@@ -83,3 +83,10 @@ class testInstanceOf() {
 
 // PHP 8.0: static return type.
 function testStatic() : ?static {}
+
+// PHP 8.2: nullable true/false.
+function fooG(): ?true {}
+function fooH(): ?false {}
+
+// Fatal error: null cannot be marked as nullable, but that's not the concern of this sniff.
+function fooI(): ?null {}

src/Standards/PSR12/Tests/Functions/NullableTypeDeclarationUnitTest.php

@@ -41,6 +41,9 @@ protected function getErrorList()
             58 => 2,
             59 => 2,
             87 => 1,
+            90 => 1,
+            91 => 1,
+            95 => 1,
         ];
 
     }//end getErrorList()