OperandsInArithmeticAdditionRule - allow benevolent unions of arrays

Author: ondrejmirtes

composer.json

@@ -7,7 +7,7 @@
 	],
 	"require": {
 		"php": "^7.2 || ^8.0",
-		"phpstan/phpstan": "^1.9.0"
+		"phpstan/phpstan": "^1.9.7"
 	},
 	"require-dev": {
 		"nikic/php-parser": "^4.13.0",

src/Rules/Operators/OperandsInArithmeticAdditionRule.php

@@ -7,9 +7,8 @@
 use PhpParser\Node\Expr\BinaryOp\Plus;
 use PHPStan\Analyser\Scope;
 use PHPStan\Rules\Rule;
-use PHPStan\Type\ArrayType;
-use PHPStan\Type\MixedType;
 use PHPStan\Type\VerbosityLevel;
+use function count;
 use function sprintf;
 
 class OperandsInArithmeticAdditionRule implements Rule
@@ -36,9 +35,7 @@ public function processNode(Node $node, Scope $scope): array
 	{
 		$leftType = $scope->getType($node->left);
 		$rightType = $scope->getType($node->right);
-		$mixedArrayType = new ArrayType(new MixedType(), new MixedType());
-
-		if ($mixedArrayType->isSuperTypeOf($leftType)->yes() && $mixedArrayType->isSuperTypeOf($rightType)->yes()) {
+		if (count($leftType->getArrays()) > 0 && count($rightType->getArrays()) > 0) {
 			return [];
 		}
 

tests/Rules/Operators/data/operators.php

@@ -113,3 +113,7 @@ function (array $array, int $int, $mixed) {
 /** @var numeric-string $numericString */
 $numericString = doFoo();
 $numericString + 1;
+
+function (\ReflectionClass $ref): void {
+	print_r(class_parents($ref->getName()) + class_implements($ref->getName()));
+};