[DowngradePhp81] Fix nullable param on DowngradeNewInInitializerRector (#245)

Author: samsonasik

rules-tests/DowngradePhp81/Rector/FunctionLike/DowngradeNewInInitializerRector/Fixture/new_not_promoted.php.inc

@@ -22,7 +22,7 @@ final class NewNotPromoted
 {
     public stdClass $obj;
 
-    public function __construct(stdClass $obj = null)
+    public function __construct(?stdClass $obj = null)
     {
         $obj ??= new stdClass;
         $this->obj = $obj;

rules/DowngradePhp81/Rector/FunctionLike/DowngradeNewInInitializerRector.php

@@ -175,6 +175,11 @@ private function replaceNewInParams(ClassMethod|Closure|Function_ $functionLike)
                 $assign = new AssignCoalesce($param->var, $default);
             }
 
+            // recheck after
+            if ($isConstructor) {
+                $param->type = $this->ensureNullableType($param->type);
+            }
+
             $stmts[] = new Expression($assign);
 
             $param->default = $this->nodeFactory->createNull();
@@ -201,28 +206,20 @@ private function ensureNullableType(Name|Identifier|ComplexType $type): Nullable
         }
 
         if ($type instanceof UnionType) {
-            if (! $this->hasNull($type)) {
-                $type->types[] = new Name('null');
+            foreach ($type->types as $typeChild) {
+                if (! $typeChild instanceof Identifier) {
+                    continue;
+                }
+
+                if ($typeChild->toLowerString() === 'null') {
+                    return $type;
+                }
             }
 
+            $type->types[] = new Identifier('null');
             return $type;
         }
 
         throw new ShouldNotHappenException();
     }
-
-    private function hasNull(UnionType $unionType): bool
-    {
-        foreach ($unionType->types as $type) {
-            if (! $type instanceof Identifier) {
-                continue;
-            }
-
-            if ($type->toLowerString() === 'null') {
-                return true;
-            }
-        }
-
-        return false;
-    }
 }

tests/Issues/DowngradeNewInArrayInitializerPromotion/Fixture/new_in_array.php.inc

@@ -33,7 +33,7 @@ class NewInArray
     /**
      * @param array<string, object> $property
      */
-    public function __construct(array $property = null)
+    public function __construct(?array $property = null)
     {
         $property ??= [
             'a' => new stdClass()