PEAR/ValidDefaultValue: handle FQN null

This commit fixes the sniff to handle "fully qualified null" as a default value, the same as unqualified null.

Includes tests.

src/Standards/PEAR/Sniffs/Functions/ValidDefaultValueSniff.php

@@ -54,11 +54,14 @@ public function process(File $phpcsFile, $stackPtr)
             }
 
             if (array_key_exists('default', $param) === true) {
-                $defaultFound = true;
+                $defaultFound   = true;
+                $defaultValueLc = strtolower($param['default']);
                 // Check if the arg is type hinted and using NULL for the default.
                 // This does not make the argument optional - it just allows NULL
                 // to be passed in.
-                if ($param['type_hint'] !== '' && strtolower($param['default']) === 'null') {
+                if ($param['type_hint'] !== ''
+                    && ($defaultValueLc === 'null' || $defaultValueLc === '\null')
+                ) {
                     $defaultFound = false;
                 }
 

src/Standards/PEAR/Tests/Functions/ValidDefaultValueUnitTest.1.inc

@@ -114,3 +114,7 @@ class ConstructorPropertyPromotionMixedWithNormalParams {
         mixed $requiredParam,
     ) {}
 }
+
+// Safeguard correct handling of FQN null as default value.
+function foo(Foo $foo = \null, $bar) {}
+function foo(Foo $foo = \null, Foz $foz = \NULL, $bar = true, $baz) {}

src/Standards/PEAR/Tests/Functions/ValidDefaultValueUnitTest.php

@@ -46,6 +46,7 @@ public function getErrorList($testFile='')
                 101 => 1,
                 106 => 1,
                 114 => 1,
+                120 => 1,
             ];
 
         default: