diff --git a/src/Functions/array/arrayIndex.h b/src/Functions/array/arrayIndex.h
index c38b8768645..dd1a8be7f25 100644
--- a/src/Functions/array/arrayIndex.h
+++ b/src/Functions/array/arrayIndex.h
@@ -660,6 +660,11 @@ struct ArrayIndexGenericNullImpl
     }
 };
 
+inline bool allowNested(const DataTypePtr & left, const DataTypePtr & right)
+{
+    return ((isNativeNumber(left) || isEnum(left)) && isNativeNumber(right)) || left->equals(*right);
+}
+
 inline bool allowArguments(const DataTypePtr & array_inner_type, const DataTypePtr & arg)
 {
     if (allowNested(array_inner_type, arg))
@@ -732,11 +737,6 @@ inline bool allowArguments(const DataTypePtr & array_inner_type, const DataTypeP
     return false;
 }
 
-inline bool allowNested(const DataTypePtr & left, const DataTypePtr & right)
-{
-    return ((isNativeNumber(left) || isEnum(left)) && isNativeNumber(right)) || left->equals(*right);
-}
-
 template <class ConcreteAction, class Name>
 class FunctionArrayIndex : public IFunction
 {