diff --git a/python/src/com/jetbrains/python/inspections/PyStringFormatInspection.java b/python/src/com/jetbrains/python/inspections/PyStringFormatInspection.java
index e7e3a3fb84ff..c1f61a726362 100644
--- a/python/src/com/jetbrains/python/inspections/PyStringFormatInspection.java
+++ b/python/src/com/jetbrains/python/inspections/PyStringFormatInspection.java
@@ -430,7 +430,7 @@ public class PyStringFormatInspection extends PyInspection {
         else {
           final PyClassType type = as(myTypeEvalContext.getType(rightExpression), PyClassType.class);
           if (type != null) {
-            if (myUsedMappingKeys.size() > 0 && !PyABCUtil.isSubclass(type.getPyClass(), PyNames.MAPPING, null)) {
+            if (myUsedMappingKeys.size() > 0 && !PyABCUtil.isSubclass(type.getPyClass(), PyNames.MAPPING, myTypeEvalContext)) {
               registerProblem(rightExpression, PyBundle.message("INSP.format.requires.mapping"));
               return;
             }
diff --git a/python/src/com/jetbrains/python/psi/types/PyABCUtil.java b/python/src/com/jetbrains/python/psi/types/PyABCUtil.java
index eaea98510c32..fc6d2ef0d831 100644
--- a/python/src/com/jetbrains/python/psi/types/PyABCUtil.java
+++ b/python/src/com/jetbrains/python/psi/types/PyABCUtil.java
@@ -107,11 +107,11 @@ public class PyABCUtil {
         final PyClassLikeType metaClassType = classType.getMetaClassType(context, true);
         if (metaClassType instanceof PyClassType) {
           final PyClassType metaClass = (PyClassType)metaClassType;
-          return isSubclass(metaClass.getPyClass(), superClassName, true, null);
+          return isSubclass(metaClass.getPyClass(), superClassName, true, context);
         }
       }
       else {
-        return isSubclass(pyClass, superClassName, true, null);
+        return isSubclass(pyClass, superClassName, true, context);
       }
     }
     if (type instanceof PyUnionType) {