9 files changed, 10 insertions, 13 deletions
diff --git a/src/test/fuzz/autofile.cpp b/src/test/fuzz/autofile.cpp
index dbc0b5ab81..479342e4be 100644
--- a/src/test/fuzz/autofile.cpp
+++ b/src/test/fuzz/autofile.cpp
@@ -2,7 +2,6 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-#include <optional.h>
 #include <streams.h>
 #include <test/fuzz/FuzzedDataProvider.h>
 #include <test/fuzz/fuzz.h>
diff --git a/src/test/fuzz/buffered_file.cpp b/src/test/fuzz/buffered_file.cpp
index ffe38f10fc..ed72260d10 100644
--- a/src/test/fuzz/buffered_file.cpp
+++ b/src/test/fuzz/buffered_file.cpp
@@ -2,7 +2,6 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-#include <optional.h>
 #include <streams.h>
 #include <test/fuzz/FuzzedDataProvider.h>
 #include <test/fuzz/fuzz.h>
diff --git a/src/test/fuzz/deserialize.cpp b/src/test/fuzz/deserialize.cpp
index 64c6e49615..66b0fdc090 100644
--- a/src/test/fuzz/deserialize.cpp
+++ b/src/test/fuzz/deserialize.cpp
@@ -15,7 +15,7 @@
 #include <net.h>
 #include <netbase.h>
 #include <node/utxo_snapshot.h>
-#include <optional.h>
+#include <optional>
 #include <primitives/block.h>
 #include <protocol.h>
 #include <psbt.h>
@@ -69,7 +69,7 @@ T Deserialize(CDataStream ds)
 }
 
 template <typename T>
-void DeserializeFromFuzzingInput(FuzzBufferType buffer, T& obj, const Optional<int> protocol_version = nullopt)
+void DeserializeFromFuzzingInput(FuzzBufferType buffer, T& obj, const std::optional<int> protocol_version = std::nullopt)
 {
     CDataStream ds(buffer, SER_NETWORK, INIT_PROTO_VERSION);
     if (protocol_version) {
diff --git a/src/test/fuzz/net.cpp b/src/test/fuzz/net.cpp
index b056f46f2e..dc2f1e2160 100644
--- a/src/test/fuzz/net.cpp
+++ b/src/test/fuzz/net.cpp
@@ -7,7 +7,7 @@
 #include <net.h>
 #include <net_permissions.h>
 #include <netaddress.h>
-#include <optional.h>
+#include <optional>
 #include <protocol.h>
 #include <random.h>
 #include <test/fuzz/FuzzedDataProvider.h>
diff --git a/src/test/fuzz/node_eviction.cpp b/src/test/fuzz/node_eviction.cpp
index 606ebfc151..603d520cf5 100644
--- a/src/test/fuzz/node_eviction.cpp
+++ b/src/test/fuzz/node_eviction.cpp
@@ -3,7 +3,6 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <net.h>
-#include <optional.h>
 #include <protocol.h>
 #include <test/fuzz/FuzzedDataProvider.h>
 #include <test/fuzz/fuzz.h>
@@ -37,7 +36,7 @@ FUZZ_TARGET(node_eviction)
     // Make a copy since eviction_candidates may be in some valid but otherwise
     // indeterminate state after the SelectNodeToEvict(&&) call.
     const std::vector<NodeEvictionCandidate> eviction_candidates_copy = eviction_candidates;
-    const Optional<NodeId> node_to_evict = SelectNodeToEvict(std::move(eviction_candidates));
+    const std::optional<NodeId> node_to_evict = SelectNodeToEvict(std::move(eviction_candidates));
     if (node_to_evict) {
         assert(std::any_of(eviction_candidates_copy.begin(), eviction_candidates_copy.end(), [&node_to_evict](const NodeEvictionCandidate& eviction_candidate) { return *node_to_evict == eviction_candidate.id; }));
     }
diff --git a/src/test/fuzz/p2p_transport_deserializer.cpp b/src/test/fuzz/p2p_transport_deserializer.cpp
index 163f1b839e..c07cf9322e 100644
--- a/src/test/fuzz/p2p_transport_deserializer.cpp
+++ b/src/test/fuzz/p2p_transport_deserializer.cpp
@@ -30,7 +30,7 @@ FUZZ_TARGET_INIT(p2p_transport_deserializer, initialize_p2p_transport_deserializ
         if (deserializer.Complete()) {
             const std::chrono::microseconds m_time{std::numeric_limits<int64_t>::max()};
             uint32_t out_err_raw_size{0};
-            Optional<CNetMessage> result{deserializer.GetMessage(m_time, out_err_raw_size)};
+            std::optional<CNetMessage> result{deserializer.GetMessage(m_time, out_err_raw_size)};
             if (result) {
                 assert(result->m_command.size() <= CMessageHeader::COMMAND_SIZE);
                 assert(result->m_raw_message_size <= buffer.size());
diff --git a/src/test/fuzz/psbt.cpp b/src/test/fuzz/psbt.cpp
index eb2754054a..e06f9d33bc 100644
--- a/src/test/fuzz/psbt.cpp
+++ b/src/test/fuzz/psbt.cpp
@@ -5,7 +5,7 @@
 #include <test/fuzz/fuzz.h>
 
 #include <node/psbt.h>
-#include <optional.h>
+#include <optional>
 #include <psbt.h>
 #include <pubkey.h>
 #include <script/script.h>
@@ -39,7 +39,7 @@ FUZZ_TARGET_INIT(psbt, initialize_psbt)
 
     (void)psbt.IsNull();
 
-    Optional<CMutableTransaction> tx = psbt.tx;
+    std::optional<CMutableTransaction> tx = psbt.tx;
     if (tx) {
         const CMutableTransaction& mtx = *tx;
         const PartiallySignedTransaction psbt_from_tx{mtx};
diff --git a/src/test/fuzz/script_descriptor_cache.cpp b/src/test/fuzz/script_descriptor_cache.cpp
index 1c62c018e7..7c88fb2f47 100644
--- a/src/test/fuzz/script_descriptor_cache.cpp
+++ b/src/test/fuzz/script_descriptor_cache.cpp
@@ -2,7 +2,7 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-#include <optional.h>
+#include <optional>
 #include <pubkey.h>
 #include <script/descriptor.h>
 #include <test/fuzz/FuzzedDataProvider.h>
diff --git a/src/test/fuzz/system.cpp b/src/test/fuzz/system.cpp
index d9571209fa..b25dcfcd3b 100644
--- a/src/test/fuzz/system.cpp
+++ b/src/test/fuzz/system.cpp
@@ -51,7 +51,7 @@ FUZZ_TARGET(system)
                 // Avoid hitting:
                 // util/system.cpp:425: void ArgsManager::AddArg(const std::string &, const std::string &, unsigned int, const OptionsCategory &): Assertion `ret.second' failed.
                 const std::string argument_name = GetArgumentName(fuzzed_data_provider.ConsumeRandomLengthString(16));
-                if (args_manager.GetArgFlags(argument_name) != nullopt) {
+                if (args_manager.GetArgFlags(argument_name) != std::nullopt) {
                     return;
                 }
                 args_manager.AddArg(argument_name, fuzzed_data_provider.ConsumeRandomLengthString(16), fuzzed_data_provider.ConsumeIntegral<unsigned int>() & ~ArgsManager::COMMAND, options_category);
@@ -63,7 +63,7 @@ FUZZ_TARGET(system)
                 std::vector<std::string> hidden_arguments;
                 for (const std::string& name : names) {
                     const std::string hidden_argument = GetArgumentName(name);
-                    if (args_manager.GetArgFlags(hidden_argument) != nullopt) {
+                    if (args_manager.GetArgFlags(hidden_argument) != std::nullopt) {
                         continue;
                     }
                     if (std::find(hidden_arguments.begin(), hidden_arguments.end(), hidden_argument) != hidden_arguments.end()) {