From 4a5f3dc498f7e159a479f81319e8a27bcbed9d7e Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@gmail.com>
Date: Tue, 18 Oct 2022 02:33:29 +0300
Subject: [PATCH] Add variant<monostate, T>::emplace tests to fish out
 -Wmaybe-uninitialized warnings

---
 test/variant_emplace_index.cpp | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/test/variant_emplace_index.cpp b/test/variant_emplace_index.cpp
index 340cbcb..6aececa 100644
--- a/test/variant_emplace_index.cpp
+++ b/test/variant_emplace_index.cpp
@@ -288,5 +288,39 @@ int main()
     BOOST_TEST_EQ( Z1::instances, 0 );
     BOOST_TEST_EQ( Z2::instances, 0 );
 
+    {
+        variant<monostate, monostate> v;
+        BOOST_TEST_EQ( v.index(), 0 );
+
+        v.emplace<0>();
+        BOOST_TEST_EQ( v.index(), 0 );
+
+        v.emplace<1>();
+        BOOST_TEST_EQ( v.index(), 1 );
+
+        v.emplace<1>();
+        BOOST_TEST_EQ( v.index(), 1 );
+
+        v.emplace<0>();
+        BOOST_TEST_EQ( v.index(), 0 );
+    }
+
+    {
+        variant<monostate, int> v;
+        BOOST_TEST_EQ( v.index(), 0 );
+
+        v.emplace<0>();
+        BOOST_TEST_EQ( v.index(), 0 );
+
+        v.emplace<1>();
+        BOOST_TEST_EQ( v.index(), 1 );
+
+        v.emplace<1>();
+        BOOST_TEST_EQ( v.index(), 1 );
+
+        v.emplace<0>();
+        BOOST_TEST_EQ( v.index(), 0 );
+    }
+
     return boost::report_errors();
 }