[Php80] Skip promotion when property type is wider than constructor param on ClassPropertyAssignToConstructorPromotionRector (#9809)

Author: ILJA MANYUTIN

rules-tests/Php80/Rector/Class_/ClassPropertyAssignToConstructorPromotionRector/Fixture/narrower_property_type.php.inc

@@ -0,0 +1,28 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\Class_\ClassPropertyAssignToConstructorPromotionRector\Fixture;
+
+final class NarrowerPropertyType
+{
+    private object $entity;
+
+    public function __construct(?object $entity)
+    {
+        $this->entity = $entity;
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\Class_\ClassPropertyAssignToConstructorPromotionRector\Fixture;
+
+final class NarrowerPropertyType
+{
+    public function __construct(private object $entity)
+    {
+    }
+}
+
+?>

rules-tests/Php80/Rector/Class_/ClassPropertyAssignToConstructorPromotionRector/Fixture/skip_wider_property_type.php.inc

@@ -0,0 +1,18 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\Class_\ClassPropertyAssignToConstructorPromotionRector\Fixture;
+
+final class SkipWiderPropertyType
+{
+    public private(set) ?object $entity = null;
+
+    public function __construct(object $entity)
+    {
+        $this->entity = $entity;
+    }
+
+    public function clear(): void
+    {
+        $this->entity = null;
+    }
+}

rules/Php80/Rector/Class_/ClassPropertyAssignToConstructorPromotionRector.php

@@ -220,6 +220,10 @@ public function refactor(Node $node): ?Node
                 continue;
             }
 
+            if ($this->shouldSkipWiderPropertyType($property, $param)) {
+                continue;
+            }
+
             $hasChanged = true;
 
             // remove property from class
@@ -479,4 +483,32 @@ private function shouldUsePropertyTypeForPromotedParam(Property $property, Param
 
         return $this->typeComparator->areTypesEqual($type, $paramTypeWithoutNull);
     }
+
+    /**
+     * Promotion shares one type. When processUnionType would copy the property type onto the
+     * param and that type is strictly wider (e.g. ?object vs object), skip — otherwise the
+     * constructor contract is loosened. Narrowing (object vs ?object) stays allowed.
+     * Interface vs implementation does not fire here: shouldUsePropertyTypeForPromotedParam
+     * is false when the non-null base types differ.
+     */
+    private function shouldSkipWiderPropertyType(Property $property, Param $param): bool
+    {
+        if (! $this->shouldUsePropertyTypeForPromotedParam($property, $param)) {
+            return false;
+        }
+
+        if (! $property->type instanceof Node || ! $param->type instanceof Node) {
+            return false;
+        }
+
+        $propertyType = $this->staticTypeMapper->mapPhpParserNodePHPStanType($property->type);
+        $paramType = $this->staticTypeMapper->mapPhpParserNodePHPStanType($param->type);
+
+        if ($param->default instanceof Expr) {
+            $paramType = TypeCombinator::union($paramType, $this->getType($param->default));
+        }
+
+        return $this->typeComparator->isSubtype($paramType, $propertyType)
+            && ! $this->typeComparator->areTypesEqual($propertyType, $paramType);
+    }
 }