QVariant: remove UB and fix semantics in a test

The code was reading from uninitialized memory when creating a
variant. Fixing that reveals that the test semantics
are broken: when dealing with datatypes without a registered
operator==, QVariant resorts to memcmp, so the two objects
would've actually compared equal. Amend that.

Change-Id: I36bad7ee6a45154d5d534b7dd8b618cc0a900126
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

1 files changed, 4 insertions, 4 deletions

diff --git a/tests/auto/corelib/kernel/qvariant/tst_qvariant.cpp b/tests/auto/corelib/kernel/qvariant/tst_qvariant.cpp
index c1c475b9c6..69322356a8 100644
--- a/tests/auto/corelib/kernel/qvariant/tst_qvariant.cpp
+++ b/tests/auto/corelib/kernel/qvariant/tst_qvariant.cpp
@@ -2865,15 +2865,15 @@ void tst_QVariant::compareCustomTypes() const
 {
     qRegisterMetaType<WontCompare>("WontCompare");
 
-    WontCompare f1;
+    WontCompare f1 = {};
     f1.x = 0;
     const QVariant variant1(QVariant::fromValue(f1));
 
-    WontCompare f2;
-    f2.x = 0;
+    WontCompare f2 = {};
+    f2.x = 1;
     const QVariant variant2(QVariant::fromValue(f2));
 
-    /* We compare pointers. */
+    /* We compare via memcmp. */
     QVERIFY(variant1 != variant2);
     QCOMPARE(variant1, variant1);
     QCOMPARE(variant2, variant2);