1 files changed, 39 insertions, 0 deletions
diff --git a/third_party/immer/test/vector/issue-46.cpp b/third_party/immer/test/vector/issue-46.cpp
new file mode 100644
index 0000000000..6475be210d
--- /dev/null
+++ b/third_party/immer/test/vector/issue-46.cpp
@@ -0,0 +1,39 @@
+//
+// immer: immutable data structures for C++
+// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+//
+// This software is distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+//
+
+// Thanks Guiguiprim for reporting this issue
+// https://github.com/arximboldi/immer/issues/46
+
+#include <immer/flex_vector.hpp>
+#include <immer/vector.hpp>
+#include <immer/vector_transient.hpp>
+
+#include <catch.hpp>
+
+TEST_CASE("operator==() may return bad result")
+{
+    using bool_vec = immer::flex_vector<bool>;
+
+    immer::vector<bool_vec> v0;
+    auto tv = v0.transient();
+    tv.push_back(bool_vec(9, false));
+    tv.push_back(bool_vec(10, false));
+    tv.push_back(bool_vec(8, false));
+    tv.push_back(bool_vec(6, false));
+    tv.push_back(bool_vec(9, false));
+    tv.push_back(bool_vec(7, false));
+    tv.push_back(bool_vec(8, false));
+    tv.push_back(bool_vec(9, false));
+    tv.push_back(bool_vec(10, false));
+    v0 = tv.persistent();
+
+    auto v1 = v0.update(1, [](bool_vec vec) { return vec.set(8, true); });
+
+    CHECK(v0[1] != v1[1]);
+    CHECK(v0 != v1);
+}