From c26ec176dd438c45ae1964b67bf0da3ebfaf1b16 Mon Sep 17 00:00:00 2001
From: Avi Kivity <avi@scylladb.com>
Date: Tue, 7 May 2019 09:21:22 +0300
Subject: [PATCH] cql parser: fix conversion from uninitalized<T> to
 optional<T> with gcc 9

We use uninitialized<T> (wrapping an optional<T>) to adjust to the
parser's way of laying out the code, but this fails with gcc 9
(presumably for the correct reasons) when converting from
uninitialized<T> back to optional<T>. Add a conversion operator
to make it build.
---
 cql3/Cql.g | 1 +
 1 file changed, 1 insertion(+)

diff --git a/cql3/Cql.g b/cql3/Cql.g
index 3c76ec1493..853d68d3d0 100644
--- a/cql3/Cql.g
+++ b/cql3/Cql.g
@@ -125,6 +125,7 @@ struct uninitialized {
     uninitialized& operator=(uninitialized&&) = default;
     operator const T&() const & { return check(), *_val; }
     operator T&&() && { return check(), std::move(*_val); }
+    operator std::optional<T>&&() && { return check(), std::move(_val); }
     void check() const { if (!_val) { throw std::runtime_error("not intitialized"); } }
 };