AK+Tests: Don't double-destroy NoAllocationGuard in TestFixedArray

This caused the m_allocation_enabled_previously member to be technically
uninitialized when the compiler emits the implicit destructor call for
stack allocated classes.
This was pointed out by gcc on lagom builds, no clue how this was flying
under the radar for so long and is not triggering CI.

1 files changed, 9 insertions, 4 deletions

diff --git a/Tests/AK/TestFixedArray.cpp b/Tests/AK/TestFixedArray.cpp
index fe34a56338..85e878791d 100644
--- a/Tests/AK/TestFixedArray.cpp
+++ b/Tests/AK/TestFixedArray.cpp
@@ -63,10 +63,15 @@ TEST_CASE(no_allocation)
 
     EXPECT_NO_CRASH("Move", [&] {
         FixedArray<int> moved_from_array = FixedArray<int>::must_create_but_fixme_should_propagate_errors(6);
-        NoAllocationGuard guard;
-        FixedArray<int> moved_to_array(move(moved_from_array));
-        // We need to ensure that this destructor runs before the FixedArray destructor.
-        guard.~NoAllocationGuard();
+        // We need an Optional here to ensure that the NoAllocationGuard is
+        // destroyed before the moved_to_array, because that would call free
+        Optional<FixedArray<int>> moved_to_array;
+
+        {
+            NoAllocationGuard guard;
+            moved_to_array.emplace(move(moved_from_array));
+        }
+
         return Test::Crash::Failure::DidNotCrash;
     });