Support string arguments

Author: lookyman

src/Type/PHPUnit/CreateMockDynamicReturnTypeExtension.php

@@ -5,6 +5,7 @@
 use PhpParser\Node\Expr\MethodCall;
 use PHPStan\Analyser\Scope;
 use PHPStan\Reflection\MethodReflection;
+use PHPStan\Type\Constant\ConstantStringType;
 use PHPStan\Type\ObjectType;
 use PHPStan\Type\Type;
 use PHPStan\Type\TypeCombinator;
@@ -41,12 +42,14 @@ public function getTypeFromMethodCall(MethodReflection $methodReflection, Method
 		}
 
 		$argType = $scope->getType($methodCall->args[$argumentIndex]->value);
-		if (!($argType instanceof TypeWithClassName)) {
+		if ($argType instanceof TypeWithClassName) {
+			$class = $argType->getClassName();
+		} elseif ($argType instanceof ConstantStringType) {
+			$class = $argType->getValue();
+		} else {
 			return $methodReflection->getReturnType();
 		}
 
-		$class = $argType->getClassName();
-
 		return TypeCombinator::intersect(
 			new ObjectType($class),
 			$methodReflection->getReturnType()