remove unused class util::Ref and its unit test

src/Makefile.am

@@ -243,7 +243,6 @@ BITCOIN_CORE_H = \
   util/moneystr.h \
   util/rbf.h \
   util/readwritefile.h \
-  util/ref.h \
   util/settings.h \
   util/sock.h \
   util/spanparsing.h \

src/Makefile.test.include

@@ -110,7 +110,6 @@ BITCOIN_TESTS =\
   test/prevector_tests.cpp \
   test/raii_event_tests.cpp \
   test/random_tests.cpp \
-  test/ref_tests.cpp \
   test/reverselock_tests.cpp \
   test/rpc_tests.cpp \
   test/sanity_tests.cpp \

src/test/ref_tests.cpp

@@ -1,33 +0,0 @@
-// Copyright (c) 2020 The Bitcoin Core developers
-// Distributed under the MIT software license, see the accompanying
-// file COPYING or http://www.opensource.org/licenses/mit-license.php.
-
-#include <util/ref.h>
-
-#include <boost/test/unit_test.hpp>
-
-BOOST_AUTO_TEST_SUITE(ref_tests)
-
-BOOST_AUTO_TEST_CASE(ref_test)
-{
-    util::Ref ref;
-    BOOST_CHECK(!ref.Has<int>());
-    BOOST_CHECK_THROW(ref.Get<int>(), NonFatalCheckError);
-    int value = 5;
-    ref.Set(value);
-    BOOST_CHECK(ref.Has<int>());
-    BOOST_CHECK_EQUAL(ref.Get<int>(), 5);
-    ++ref.Get<int>();
-    BOOST_CHECK_EQUAL(ref.Get<int>(), 6);
-    BOOST_CHECK_EQUAL(value, 6);
-    ++value;
-    BOOST_CHECK_EQUAL(value, 7);
-    BOOST_CHECK_EQUAL(ref.Get<int>(), 7);
-    BOOST_CHECK(!ref.Has<bool>());
-    BOOST_CHECK_THROW(ref.Get<bool>(), NonFatalCheckError);
-    ref.Clear();
-    BOOST_CHECK(!ref.Has<int>());
-    BOOST_CHECK_THROW(ref.Get<int>(), NonFatalCheckError);
-}
-
-BOOST_AUTO_TEST_SUITE_END()

src/util/ref.h

@@ -1,38 +0,0 @@
-// Copyright (c) 2020 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_REF_H
-#define BITCOIN_UTIL_REF_H
-
-#include <util/check.h>
-
-#include <typeindex>
-
-namespace util {
-
-/**
- * Type-safe dynamic reference.
- *
- * This implements a small subset of the functionality in C++17's std::any
- * class, and can be dropped when the project updates to C++17
- * (https://github.com/bitcoin/bitcoin/issues/16684)
- */
-class Ref
-{
-public:
-    Ref() = default;
-    template<typename T> Ref(T& value) { Set(value); }
-    template<typename T> T& Get() const { CHECK_NONFATAL(Has<T>()); return *static_cast<T*>(m_value); }
-    template<typename T> void Set(T& value) { m_value = &value; m_type = std::type_index(typeid(T)); }
-    template<typename T> bool Has() const { return m_value && m_type == std::type_index(typeid(T)); }
-    void Clear() { m_value = nullptr; m_type = std::type_index(typeid(void)); }
-
-private:
-    void* m_value = nullptr;
-    std::type_index m_type = std::type_index(typeid(void));
-};
-
-} // namespace util
-
-#endif // BITCOIN_UTIL_REF_H

test/lint/extended-lint-cppcheck.sh

@@ -57,7 +57,6 @@ IGNORED_WARNINGS=(
     "src/test/checkqueue_tests.cpp:.* Struct 'UniqueCheck' has a constructor with 1 argument that is not explicit."
     "src/test/fuzz/util.h:.* Class 'FuzzedFileProvider' has a constructor with 1 argument that is not explicit."
     "src/test/fuzz/util.h:.* Class 'FuzzedAutoFileProvider' has a constructor with 1 argument that is not explicit."
-    "src/util/ref.h:.* Class 'Ref' has a constructor with 1 argument that is not explicit."
     "src/wallet/db.h:.* Class 'BerkeleyEnvironment' has a constructor with 1 argument that is not explicit."
 )