diff --git a/src/Interpreters/JoinToSubqueryTransformVisitor.cpp b/src/Interpreters/JoinToSubqueryTransformVisitor.cpp
index 3d5c096e8cf..5879c96f7b3 100644
--- a/src/Interpreters/JoinToSubqueryTransformVisitor.cpp
+++ b/src/Interpreters/JoinToSubqueryTransformVisitor.cpp
@@ -546,9 +546,9 @@ std::vector<TableNeededColumns> normalizeColumnNamesExtractNeeded(
                 {
                     auto alias = aliases.find(ident->name())->second;
                     auto alias_ident = alias->clone();
-                    if ( alias_ident->as<ASTIdentifier>())
+                    if (auto * alias_ident_typed = alias_ident->as<ASTIdentifier>())
                     {
-                        alias_ident->as<ASTIdentifier>()->restoreTable();
+                        alias_ident_typed->restoreTable();
                         bool alias_equals_column_name = alias_ident->getColumnNameWithoutAlias() == ident->getColumnNameWithoutAlias();
                         if (!alias_equals_column_name)
                             throw Exception("Alias clashes with qualified column '" + ident->name() + "'", ErrorCodes::AMBIGUOUS_COLUMN_NAME);