Fix issue with self reference constants

Author: jaapio

src/phpDocumentor/Reflection/Php/Expression/ExpressionPrinter.php

@@ -24,6 +24,8 @@
 use PhpParser\Node\Name;
 use PhpParser\PrettyPrinter\Standard;
 
+use function ltrim;
+
 final class ExpressionPrinter extends Standard
 {
     /** @var array<string, Fqsen|Type> */
@@ -93,7 +95,7 @@ protected function pExpr_ClassConstFetch(Expr\ClassConstFetch $node): string
 
         $placeholder = Expression::generatePlaceholder((string) $renderedName);
         $this->parts[$placeholder] = new Fqsen(
-            $className . '::' . $renderedName,
+            '\\' . ltrim((string) $className, '\\') . '::' . $renderedName,
         );
 
         return $placeholder;

tests/unit/phpDocumentor/Reflection/Php/Expression/ExpressionPrinterTest.php

@@ -63,6 +63,13 @@ public static function argumentProvider(): array
                     '{{ PHPDOCe54b7c24dd0f847c3193039223751b3d }}' => new Fqsen('\MyClass::SOME_CONST'),
                 ],
             ],
+            'selfConstantDefault' => [
+                'code' => '<?php function foo(MyClass $arg = self::SOME_CONST) {}',
+                'expectedExpression' => '{{ PHPDOCe54b7c24dd0f847c3193039223751b3d }}',
+                'expectedParts' => [
+                    '{{ PHPDOCe54b7c24dd0f847c3193039223751b3d }}' => new Fqsen('\self::SOME_CONST'),
+                ],
+            ],
             'stringDefault' => [
                 'code' => '<?php function foo(string $arg = \'hello\') {}',
                 'expectedExpression' => "'hello'",