diff --git a/src/Storages/System/StorageSystemDataSkippingIndices.cpp b/src/Storages/System/StorageSystemDataSkippingIndices.cpp
index ccb52e9a23a..aa0f186b56a 100644
--- a/src/Storages/System/StorageSystemDataSkippingIndices.cpp
+++ b/src/Storages/System/StorageSystemDataSkippingIndices.cpp
@@ -127,7 +127,7 @@ protected:
                     // 'type_full' column
                     if (column_mask[src_index++])
                     {
-                        if (auto expression = index.definition_ast->as<ASTIndexDeclaration>())
+                        if (auto * expression = index.definition_ast->as<ASTIndexDeclaration>())
                             res_columns[res_index++]->insert(queryToString(expression->type->clone()));
                         else
                             res_columns[res_index++]->insertDefault();