diff --git a/python/src/com/jetbrains/python/inspections/PyStringFormatInspection.java b/python/src/com/jetbrains/python/inspections/PyStringFormatInspection.java
index a2be27d5ef7c..f02ed70a8660 100644
--- a/python/src/com/jetbrains/python/inspections/PyStringFormatInspection.java
+++ b/python/src/com/jetbrains/python/inspections/PyStringFormatInspection.java
@@ -219,7 +219,8 @@ public class PyStringFormatInspection extends PyInspection {
           final PyType stringType = PyBuiltinCache.getInstance(rightExpression).getStringType(LanguageLevel.forElement(rightExpression));
           final PyType listType = PyBuiltinCache.getInstance(rightExpression).getListType();
 
-          if (type == null || PyTypeChecker.match(listType, type, myTypeEvalContext)
+          if (type == null) return -1;
+          if (PyTypeChecker.match(listType, type, myTypeEvalContext)
               || PyTypeChecker.match(stringType, type, myTypeEvalContext)) {
             checkTypeCompatible(problemTarget, builtinCache.getStrType(),
                                 PyTypeParser.getTypeByName(problemTarget, s));