From f1907836facb2955eba2e1acea309d9e5e725fdc Mon Sep 17 00:00:00 2001
From: Marcus Tillmanns <marcus.tillmanns@qt.io>
Date: Tue, 19 Sep 2023 08:17:31 +0200
Subject: [PATCH] Expected: Fix operator==(void, void)

Change-Id: I883f05155f0710fc3a9f92a2e33d4f8722159016
Reviewed-by: David Schulz <david.schulz@qt.io>
---
 .../tl_expected/include/tl/expected.hpp       | 15 +++++++++++++++
 tests/auto/utils/expected/tst_expected.cpp    | 19 +++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/src/libs/3rdparty/tl_expected/include/tl/expected.hpp b/src/libs/3rdparty/tl_expected/include/tl/expected.hpp
index d8ed472bdd1..56101d36331 100644
--- a/src/libs/3rdparty/tl_expected/include/tl/expected.hpp
+++ b/src/libs/3rdparty/tl_expected/include/tl/expected.hpp
@@ -2278,6 +2278,14 @@ detail::decay_t<Exp> or_else_impl(Exp &&exp, F &&f) {
 #endif
 } // namespace detail
 
+template <class E, class F>
+constexpr bool operator==(const expected<void, E> &lhs,
+                          const expected<void, F> &rhs) {
+  return (lhs.has_value() != rhs.has_value())
+             ? false
+             : (!lhs.has_value() ? lhs.error() == rhs.error() : true);
+}
+
 template <class T, class E, class U, class F>
 constexpr bool operator==(const expected<T, E> &lhs,
                           const expected<U, F> &rhs) {
@@ -2292,6 +2300,13 @@ constexpr bool operator!=(const expected<T, E> &lhs,
              ? true
              : (!lhs.has_value() ? lhs.error() != rhs.error() : *lhs != *rhs);
 }
+template<class E, class F>
+constexpr bool operator!=(const expected<void, E> &lhs, const expected<void, F> &rhs)
+{
+    return (lhs.has_value() != rhs.has_value())
+               ? true
+               : (!lhs.has_value() ? lhs.error() != rhs.error() : false);
+}
 
 template <class T, class E, class U>
 constexpr bool operator==(const expected<T, E> &x, const U &v) {
diff --git a/tests/auto/utils/expected/tst_expected.cpp b/tests/auto/utils/expected/tst_expected.cpp
index 43e58fb4f90..25240b861a7 100644
--- a/tests/auto/utils/expected/tst_expected.cpp
+++ b/tests/auto/utils/expected/tst_expected.cpp
@@ -32,6 +32,25 @@ private slots:
 
         QVERIFY(!result);
     }
+
+    void tryCompareVoid()
+    {
+        tl::expected<void, QString> e1;
+        QVERIFY(e1 == e1);
+
+        tl::expected<void, QString> e2 = make_unexpected("error");
+        QVERIFY(e1 != e2);
+
+        e1 = make_unexpected(QString("error"));
+        QVERIFY(e1 == e2);
+
+        e2 = {};
+        QVERIFY(e1 != e2);
+
+        e1 = {};
+        QVERIFY(e1 == e2);
+        QVERIFY(!(e1 != e2));
+    }
 };
 QTEST_GUILESS_MAIN(tst_expected)