Fix BenevolentUnionType::traverseSimultaneously()

Author: ondrejmirtes

src/Type/BenevolentUnionType.php

@@ -151,31 +151,12 @@ public function traverse(callable $cb): Type
 
 	public function traverseSimultaneously(Type $right, callable $cb): Type
 	{
-		$types = [];
-		$changed = false;
-
-		if (!$right instanceof UnionType) {
-			return $this;
-		}
-
-		if (count($this->getTypes()) !== count($right->getTypes())) {
+		$newType = parent::traverseSimultaneously($right, $cb);
+		if ($newType === $this) {
 			return $this;
 		}
 
-		foreach ($this->getSortedTypes() as $i => $leftType) {
-			$rightType = $right->getSortedTypes()[$i];
-			$newType = $cb($leftType, $rightType);
-			if ($leftType !== $newType) {
-				$changed = true;
-			}
-			$types[] = $newType;
-		}
-
-		if ($changed) {
-			return TypeUtils::toBenevolentUnion(TypeCombinator::union(...$types));
-		}
-
-		return $this;
+		return TypeUtils::toBenevolentUnion($newType);
 	}
 
 }

tests/PHPStan/Type/SimultaneousTypeTraverserTest.php

@@ -57,7 +57,7 @@ public static function dataChangeStringIntoNonEmptyString(): iterable
 				new IntegerType(),
 				new FloatType(),
 			]),
-			'(int|string)',
+			'(int|non-empty-string)',
 		];
 
 		yield [
@@ -104,6 +104,14 @@ public static function dataDescriptionBased(): iterable
 
 			return $right;
 		};
+
+		yield [
+			'__benevolent<object|int>',
+			'1|2|3',
+			$chooseScalarSubtype,
+			'(1|2|3|object)',
+		];
+
 		yield [
 			'object|int',
 			'1|2|3',