Use designated initializers

src/util/designator.h

@@ -0,0 +1,21 @@
+// Copyright (c) 2022 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_UTIL_DESIGNATOR_H
+#define BITCOIN_UTIL_DESIGNATOR_H
+
+/**
+ * Designated initializers can be used to avoid ordering mishaps in aggregate
+ * initialization. However, they do not prevent uninitialized members. The
+ * checks can be disabled by defining DISABLE_DESIGNATED_INITIALIZER_ERRORS.
+ * This should only be needed on MSVC 2019. MSVC 2022 supports them with the
+ * option "/std:c++20"
+ */
+#ifndef DISABLE_DESIGNATED_INITIALIZER_ERRORS
+#define Desig(field_name) .field_name =
+#else
+#define Desig(field_name)
+#endif
+
+#endif // BITCOIN_UTIL_DESIGNATOR_H