Fix Serializer return type for arrays of primitives

Author: yoeunes

src/Type/Symfony/SerializerDynamicReturnTypeExtension.php

@@ -6,9 +6,13 @@
 use PHPStan\Analyser\Scope;
 use PHPStan\Reflection\MethodReflection;
 use PHPStan\Type\ArrayType;
+use PHPStan\Type\BooleanType;
 use PHPStan\Type\DynamicMethodReturnTypeExtension;
+use PHPStan\Type\FloatType;
+use PHPStan\Type\IntegerType;
 use PHPStan\Type\MixedType;
 use PHPStan\Type\ObjectType;
+use PHPStan\Type\StringType;
 use PHPStan\Type\Type;
 use PHPStan\Type\TypeCombinator;
 use function count;
@@ -67,6 +71,17 @@ private function getType(string $objectName): Type
 			return new ArrayType(new MixedType(false), $this->getType(substr($objectName, 0, -2)));
 		}
 
+		switch ($objectName) {
+			case 'int':
+				return new IntegerType();
+			case 'string':
+				return new StringType();
+			case 'bool':
+				return new BooleanType();
+			case 'float':
+				return new FloatType();
+		}
+
 		return new ObjectType($objectName);
 	}
 

tests/Type/Symfony/ExtensionTest.php

@@ -54,6 +54,7 @@ public function dataFileAsserts(): iterable
 		}
 
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/serializer.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/serializer_primitives.php');
 
 		if (class_exists('Symfony\Component\HttpFoundation\InputBag')) {
 			yield from $this->gatherAssertTypes(__DIR__ . '/data/input_bag_from_request.php');

tests/Type/Symfony/data/serializer_primitives.php

@@ -0,0 +1,12 @@
+<?php declare(strict_types = 1);
+
+use function PHPStan\Testing\assertType;
+
+$serializer = new \Symfony\Component\Serializer\Serializer();
+
+assertType('int', $serializer->deserialize('...', 'int[]', 'json')[0] + 1);
+assertType('string', $serializer->deserialize('...', 'string[]', 'json')[0] . '');
+assertType('bool', !$serializer->deserialize('...', 'bool[]', 'json')[0]);
+assertType('float', $serializer->deserialize('...', 'float[]', 'json')[0] + 1.0);
+assertType('int', $serializer->deserialize('...', 'int[][]', 'json')[0][0] + 1);
+