Try

Author: VincentLanglet

src/Type/Php/IsAFunctionTypeSpecifyingHelper.php

@@ -3,6 +3,7 @@
 namespace PHPStan\Type\Php;
 
 use PHPStan\DependencyInjection\AutowiredService;
+use PHPStan\Reflection\ReflectionProvider;
 use PHPStan\Type\ClassStringType;
 use PHPStan\Type\Constant\ConstantStringType;
 use PHPStan\Type\Generic\GenericClassStringType;
@@ -22,6 +23,12 @@
 final class IsAFunctionTypeSpecifyingHelper
 {
 
+	public function __construct(
+		private ReflectionProvider $reflectionProvider,
+	)
+	{
+	}
+
 	public function determineType(
 		Type $objectOrClassType,
 		Type $classType,
@@ -38,16 +45,18 @@ public function determineType(
 		}
 
 		$isUncertain = $classType->getConstantStrings() === [];
+		$reflectionProvider = $this->reflectionProvider;
 
 		$resultType = TypeTraverser::map(
 			$classType,
-			static function (Type $type, callable $traverse) use ($objectOrClassType, $objectOrClassTypeClassNames, $allowString, $allowSameClass, &$isUncertain): Type {
+			static function (Type $type, callable $traverse) use ($reflectionProvider, $objectOrClassType, $objectOrClassTypeClassNames, $allowString, $allowSameClass, &$isUncertain): Type {
 				if ($type instanceof UnionType || $type instanceof IntersectionType) {
 					return $traverse($type);
 				}
 				if ($type instanceof ConstantStringType) {
+					$typeValue = $type->getValue();
 					if (!$allowSameClass) {
-						if ($objectOrClassTypeClassNames === [$type->getValue()]) {
+						if ($objectOrClassTypeClassNames === [$typeValue]) {
 							$isSameClass = true;
 							foreach ($objectOrClassType->getObjectClassReflections() as $classReflection) {
 								if (!$classReflection->isFinal()) {
@@ -63,10 +72,20 @@ static function (Type $type, callable $traverse) use ($objectOrClassType, $objec
 
 						if (
 							// For object, as soon as the exact same type is provided
-							// in the list we cannot be sure of the result
-							in_array($type->getValue(), $objectOrClassTypeClassNames, true)
+							// in the list we cannot be sure of the result except for interfaces
+							(
+								in_array($typeValue, $objectOrClassTypeClassNames, true)
+								&& (
+									!$reflectionProvider->hasClass($typeValue)
+									|| !$reflectionProvider->getClass($typeValue)->isInterface()
+								)
+							)
 							// This also occurs for generic class string
-							|| ($allowString && $objectOrClassTypeClassNames === [] && $objectOrClassType->isSuperTypeOf($type)->yes())
+							|| (
+								$allowString
+								&& $objectOrClassTypeClassNames === []
+								&& $objectOrClassType->isSuperTypeOf($type)->yes()
+							)
 						) {
 							$isUncertain = true;
 						}