diff --git a/.clang-tidy b/.clang-tidy
index b8567b2e..07e0dd2e 100644
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -1,8 +1,12 @@
 UseColor: true
 Checks:
   - -*
+
   - bugprone-*
     # kind of nonsense
   - -bugprone-easily-swappable-parameters
     # many warnings due to not recognizing `assert` properly
   - -bugprone-unchecked-optional-access
+
+  - modernize-*
+  - -modernize-use-trailing-return-type
diff --git a/src/hydra-evaluator/hydra-evaluator.cc b/src/hydra-evaluator/hydra-evaluator.cc
index 59ffabed..b48da7c9 100644
--- a/src/hydra-evaluator/hydra-evaluator.cc
+++ b/src/hydra-evaluator/hydra-evaluator.cc
@@ -14,11 +14,12 @@
 #include <sys/wait.h>
 
 #include <boost/format.hpp>
+#include <utility>
 
 using namespace nix;
 using boost::format;
 
-typedef std::pair<std::string, std::string> JobsetName;
+using JobsetName = std::pair<std::string, std::string>;
 
 class JobsetId {
     public:
@@ -28,8 +29,8 @@ class JobsetId {
     int id;
 
 
-    JobsetId(const std::string & project, const std::string & jobset, int id)
-        : project{ project }, jobset{ jobset }, id{ id }
+    JobsetId(std::string  project, std::string  jobset, int id)
+        : project{std::move( project )}, jobset{std::move( jobset )}, id{ id }
     {
     }
 
@@ -41,7 +42,7 @@ class JobsetId {
     friend bool operator== (const JobsetId & lhs, const JobsetName & rhs);
     friend bool operator!= (const JobsetId & lhs, const JobsetName & rhs);
 
-    std::string display() const {
+    [[nodiscard]] std::string display() const {
         return str(format("%1%:%2% (jobset#%3%)") % project % jobset % id);
     }
 };
@@ -92,7 +93,7 @@ struct Evaluator
         Pid pid;
     };
 
-    typedef std::map<JobsetId, Jobset> Jobsets;
+    using Jobsets = std::map<JobsetId, Jobset>;
 
     std::optional<JobsetName> evalOne;
 
@@ -138,7 +139,7 @@ struct Evaluator
 
             if (evalOne && name != *evalOne) continue;
 
-            auto res = state->jobsets.try_emplace(name, Jobset{name});
+            auto res = state->jobsets.try_emplace(name, Jobset{.name=name});
 
             auto & jobset = res.first->second;
             jobset.lastCheckedTime = row["lastCheckedTime"].as<time_t>(0);
@@ -180,7 +181,7 @@ struct Evaluator
 
     void startEval(State & state, Jobset & jobset)
     {
-        time_t now = time(0);
+        time_t now = time(nullptr);
 
         printInfo("starting evaluation of jobset ‘%s’ (last checked %d s ago)",
             jobset.name.display(),
@@ -233,7 +234,7 @@ struct Evaluator
             return false;
         }
 
-        if (jobset.lastCheckedTime + jobset.checkInterval <= time(0)) {
+        if (jobset.lastCheckedTime + jobset.checkInterval <= time(nullptr)) {
             // Time to schedule a fresh evaluation. If the jobset
             // is a ONE_AT_A_TIME jobset, ensure the previous jobset
             // has no remaining, unfinished work.
@@ -306,7 +307,7 @@ struct Evaluator
 
         /* Put jobsets in order of ascending trigger time, last checked
            time, and name. */
-        std::sort(sorted.begin(), sorted.end(),
+        std::ranges::sort(sorted,
             [](const Jobsets::iterator & a, const Jobsets::iterator & b) {
                 return
                     a->second.triggerTime != b->second.triggerTime
@@ -329,7 +330,7 @@ struct Evaluator
 
         while (true) {
 
-            time_t now = time(0);
+            time_t now = time(nullptr);
 
             std::chrono::seconds sleepTime = std::chrono::seconds::max();
 
@@ -416,7 +417,7 @@ struct Evaluator
                         printInfo("evaluation of jobset ‘%s’ %s",
                             jobset.name.display(), statusToString(status));
 
-                        auto now = time(0);
+                        auto now = time(nullptr);
 
                         jobset.triggerTime = notTriggered;
                         jobset.lastCheckedTime = now;
diff --git a/src/hydra-queue-runner/build-remote.cc b/src/hydra-queue-runner/build-remote.cc
index cde1e84b..352b2208 100644
--- a/src/hydra-queue-runner/build-remote.cc
+++ b/src/hydra-queue-runner/build-remote.cc
@@ -1,5 +1,6 @@
 #include <algorithm>
 #include <cmath>
+#include <ranges>
 
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -134,8 +135,8 @@ static void copyClosureTo(
     auto sorted = destStore.topoSortPaths(closure);
 
     StorePathSet missing;
-    for (auto i = sorted.rbegin(); i != sorted.rend(); ++i)
-        if (!present.count(*i)) missing.insert(*i);
+    for (auto & i : std::ranges::reverse_view(sorted))
+        if (!present.count(i)) missing.insert(i);
 
     printMsg(lvlDebug, "sending %d missing paths", missing.size());
 
@@ -305,12 +306,12 @@ static BuildResult performBuild(
 
     time_t startTime, stopTime;
 
-    startTime = time(0);
+    startTime = time(nullptr);
     {
         MaintainCount<counter> mc(nrStepsBuilding);
         result = ServeProto::Serialise<BuildResult>::read(localStore, conn);
     }
-    stopTime = time(0);
+    stopTime = time(nullptr);
 
     if (!result.startTime) {
         // If the builder gave `startTime = 0`, use our measurements
@@ -339,10 +340,10 @@ static BuildResult performBuild(
             // were known
             assert(outputPath);
             auto outputHash = outputHashes.at(outputName);
-            auto drvOutput = DrvOutput { outputHash, outputName };
+            auto drvOutput = DrvOutput { .drvHash=outputHash, .outputName=outputName };
             result.builtOutputs.insert_or_assign(
                 std::move(outputName),
-                Realisation { drvOutput, *outputPath });
+                Realisation { .id=drvOutput, .outPath=*outputPath });
         }
     }
 
@@ -635,7 +636,7 @@ void State::buildRemote(ref<Store> destStore,
          * copying outputs and we end up building too many things that we
          * haven't been able to allow copy slots for. */
         assert(reservation.unique());
-        reservation = 0;
+        reservation = nullptr;
         wakeDispatcher();
 
         StorePathSet outputs;
diff --git a/src/hydra-queue-runner/builder.cc b/src/hydra-queue-runner/builder.cc
index a5109f62..3f340c72 100644
--- a/src/hydra-queue-runner/builder.cc
+++ b/src/hydra-queue-runner/builder.cc
@@ -58,7 +58,7 @@ void State::builder(MachineReservation::ptr reservation)
     /* If the machine hasn't been released yet, release and wake up the dispatcher. */
     if (reservation) {
         assert(reservation.unique());
-        reservation = 0;
+        reservation = nullptr;
         wakeDispatcher();
     }
 
@@ -190,7 +190,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
         }
     });
 
-    time_t stepStartTime = result.startTime = time(0);
+    time_t stepStartTime = result.startTime = time(nullptr);
 
     /* If any of the outputs have previously failed, then don't bother
        building again. */
@@ -237,7 +237,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
         }
     }
 
-    time_t stepStopTime = time(0);
+    time_t stepStopTime = time(nullptr);
     if (!result.stopTime) result.stopTime = stepStopTime;
 
     /* For standard failures, we don't care about the error
diff --git a/src/hydra-queue-runner/dispatcher.cc b/src/hydra-queue-runner/dispatcher.cc
index a477321e..050e20ad 100644
--- a/src/hydra-queue-runner/dispatcher.cc
+++ b/src/hydra-queue-runner/dispatcher.cc
@@ -190,7 +190,7 @@ system_time State::doDispatch()
         }
     }
 
-    sort(runnableSorted.begin(), runnableSorted.end(),
+    std::ranges::sort(runnableSorted,
         [](const StepInfo & a, const StepInfo & b)
         {
             return
@@ -240,7 +240,7 @@ system_time State::doDispatch()
            - Then by speed factor.
 
            - Finally by load. */
-        sort(machinesSorted.begin(), machinesSorted.end(),
+        std::ranges::sort(machinesSorted,
             [](const MachineInfo & a, const MachineInfo & b) -> bool
             {
                 float ta = std::round(static_cast<float>(a.currentJobs) / a.machine->speedFactorFloat);
@@ -345,7 +345,7 @@ void State::abortUnsupported()
     auto machines2 = *machines.lock();
 
     system_time now = std::chrono::system_clock::now();
-    auto now2 = time(0);
+    auto now2 = time(nullptr);
 
     std::unordered_set<Step::ptr> aborted;
 
@@ -436,7 +436,7 @@ void Jobset::addStep(time_t startTime, time_t duration)
 
 void Jobset::pruneSteps()
 {
-    time_t now = time(0);
+    time_t now = time(nullptr);
     auto steps_(steps.lock());
     while (!steps_->empty()) {
         auto i = steps_->begin();
@@ -464,7 +464,7 @@ State::MachineReservation::~MachineReservation()
     auto prev = machine->state->currentJobs--;
     assert(prev);
     if (prev == 1)
-        machine->state->idleSince = time(0);
+        machine->state->idleSince = time(nullptr);
 
     {
         auto machineTypes_(state.machineTypes.lock());
diff --git a/src/hydra-queue-runner/hydra-build-result.hh b/src/hydra-queue-runner/hydra-build-result.hh
index 7d47f67c..8e852b2e 100644
--- a/src/hydra-queue-runner/hydra-build-result.hh
+++ b/src/hydra-queue-runner/hydra-build-result.hh
@@ -14,7 +14,7 @@ struct BuildProduct
     bool isRegular = false;
     std::optional<nix::Hash> sha256hash;
     std::optional<off_t> fileSize;
-    BuildProduct() { }
+    BuildProduct() = default;
 };
 
 struct BuildMetric
diff --git a/src/hydra-queue-runner/hydra-queue-runner.cc b/src/hydra-queue-runner/hydra-queue-runner.cc
index 71acfdbb..421c8836 100644
--- a/src/hydra-queue-runner/hydra-queue-runner.cc
+++ b/src/hydra-queue-runner/hydra-queue-runner.cc
@@ -138,7 +138,7 @@ nix::MaintainCount<counter> State::startDbUpdate()
 {
     if (nrActiveDbUpdates > 6)
         printError("warning: %d concurrent database updates; PostgreSQL may be stalled", nrActiveDbUpdates.load());
-    return MaintainCount<counter>(nrActiveDbUpdates);
+    return {nrActiveDbUpdates};
 }
 
 
@@ -171,7 +171,7 @@ void State::parseMachines(const std::string & contents)
         for (auto & f : mandatoryFeatures)
             supportedFeatures.insert(f);
 
-        using MaxJobs = std::remove_const<decltype(nix::Machine::maxJobs)>::type;
+        using MaxJobs = std::remove_const_t<decltype(nix::Machine::maxJobs)>;
 
         auto machine = std::make_shared<::Machine>(::Machine {{
             // `storeUri`, not yet used
@@ -594,7 +594,7 @@ std::shared_ptr<PathLocks> State::acquireGlobalLock()
     createDirs(dirOf(lockPath));
 
     auto lock = std::make_shared<PathLocks>();
-    if (!lock->lockPaths(PathSet({lockPath}), "", false)) return 0;
+    if (!lock->lockPaths(PathSet({lockPath}), "", false)) return nullptr;
 
     return lock;
 }
@@ -602,10 +602,10 @@ std::shared_ptr<PathLocks> State::acquireGlobalLock()
 
 void State::dumpStatus(Connection & conn)
 {
-    time_t now = time(0);
+    time_t now = time(nullptr);
     json statusJson = {
         {"status", "up"},
-        {"time", time(0)},
+        {"time", time(nullptr)},
         {"uptime", now - startedAt},
         {"pid", getpid()},
 
@@ -706,7 +706,7 @@ void State::dumpStatus(Connection & conn)
                 };
                 if (i.second.runnable > 0)
                     machineTypeJson["waitTime"] = i.second.waitTime.count() +
-                        i.second.runnable * (time(0) - lastDispatcherCheck);
+                        i.second.runnable * (time(nullptr) - lastDispatcherCheck);
                 if (i.second.running == 0)
                     machineTypeJson["lastActive"] = std::chrono::system_clock::to_time_t(i.second.lastActive);
             }
@@ -848,7 +848,7 @@ void State::run(BuildID buildOne)
     /* Can't be bothered to shut down cleanly. Goodbye! */
     auto callback = createInterruptCallback([&]() { std::_Exit(0); });
 
-    startedAt = time(0);
+    startedAt = time(nullptr);
     this->buildOne = buildOne;
 
     auto lock = acquireGlobalLock();
diff --git a/src/hydra-queue-runner/nar-extractor.cc b/src/hydra-queue-runner/nar-extractor.cc
index 7a4dd996..b3350193 100644
--- a/src/hydra-queue-runner/nar-extractor.cc
+++ b/src/hydra-queue-runner/nar-extractor.cc
@@ -3,6 +3,7 @@
 #include "archive.hh"
 
 #include <unordered_set>
+#include <utility>
 
 using namespace nix;
 
@@ -18,8 +19,8 @@ struct Extractor : ParseSink
     NarMemberData * curMember = nullptr;
     Path prefix;
 
-    Extractor(NarMemberDatas & members, const Path & prefix)
-        : members(members), prefix(prefix)
+    Extractor(NarMemberDatas & members, Path  prefix)
+        : members(members), prefix(std::move(prefix))
     { }
 
     void createDirectory(const Path & path) override
diff --git a/src/hydra-queue-runner/nar-extractor.hh b/src/hydra-queue-runner/nar-extractor.hh
index e6ba91b0..59d3fae2 100644
--- a/src/hydra-queue-runner/nar-extractor.hh
+++ b/src/hydra-queue-runner/nar-extractor.hh
@@ -13,7 +13,7 @@ struct NarMemberData
     std::optional<nix::Hash> sha256;
 };
 
-typedef std::map<nix::Path, NarMemberData> NarMemberDatas;
+using NarMemberDatas = std::map<nix::Path, NarMemberData>;
 
 /* Read a NAR from a source and get to some info about every file
    inside the NAR. */
diff --git a/src/hydra-queue-runner/queue-monitor.cc b/src/hydra-queue-runner/queue-monitor.cc
index 019d4e6f..202ebd61 100644
--- a/src/hydra-queue-runner/queue-monitor.cc
+++ b/src/hydra-queue-runner/queue-monitor.cc
@@ -4,7 +4,8 @@
 #include "thread-pool.hh"
 
 #include <cstring>
-#include <signal.h>
+#include <utility>
+#include <csignal>
 
 using namespace nix;
 
@@ -88,7 +89,7 @@ void State::queueMonitorLoop(Connection & conn)
 
 struct PreviousFailure : public std::exception {
     Step::ptr step;
-    PreviousFailure(Step::ptr step) : step(step) { }
+    PreviousFailure(Step::ptr step) : step(std::move(step)) { }
 };
 
 
@@ -117,7 +118,7 @@ bool State::getQueuedBuilds(Connection & conn,
 
         for (auto const & row : res) {
             auto builds_(builds.lock());
-            BuildID id = row["id"].as<BuildID>();
+            auto id = row["id"].as<BuildID>();
             if (buildOne && id != buildOne) continue;
             if (builds_->count(id)) continue;
 
@@ -137,7 +138,7 @@ bool State::getQueuedBuilds(Connection & conn,
 
             newIDs.push_back(id);
             newBuildsByID[id] = build;
-            newBuildsByPath.emplace(std::make_pair(build->drvPath, id));
+            newBuildsByPath.emplace(build->drvPath, id);
         }
     }
 
@@ -162,7 +163,7 @@ bool State::getQueuedBuilds(Connection & conn,
                     ("update Builds set finished = 1, buildStatus = $2, startTime = $3, stopTime = $3 where id = $1 and finished = 0",
                      build->id,
                      (int) bsAborted,
-                     time(0));
+                     time(nullptr));
                 txn.commit();
                 build->finishedInDB = true;
                 nrBuildsDone++;
@@ -176,7 +177,7 @@ bool State::getQueuedBuilds(Connection & conn,
         /* Create steps for this derivation and its dependencies. */
         try {
             step = createStep(destStore, conn, build, build->drvPath,
-                build, 0, finishedDrvs, newSteps, newRunnable);
+                build, nullptr, finishedDrvs, newSteps, newRunnable);
         } catch (PreviousFailure & ex) {
 
             /* Some step previously failed, so mark the build as
@@ -221,7 +222,7 @@ bool State::getQueuedBuilds(Connection & conn,
                      "where id = $1 and finished = 0",
                      build->id,
                      (int) (ex.step->drvPath == build->drvPath ? bsFailed : bsDepFailed),
-                     time(0));
+                     time(nullptr));
                 notifyBuildFinished(txn, build->id, {});
                 txn.commit();
                 build->finishedInDB = true;
@@ -254,7 +255,7 @@ bool State::getQueuedBuilds(Connection & conn,
             {
             auto mc = startDbUpdate();
             pqxx::work txn(conn);
-            time_t now = time(0);
+            time_t now = time(nullptr);
             if (!buildOneDone && build->id == buildOne) buildOneDone = true;
             printMsg(lvlInfo, "marking build %1% as succeeded (cached)", build->id);
             markSucceededBuild(txn, build, res, true, now, now);
@@ -438,7 +439,7 @@ Step::ptr State::createStep(ref<Store> destStore,
     Build::ptr referringBuild, Step::ptr referringStep, std::set<StorePath> & finishedDrvs,
     std::set<Step::ptr> & newSteps, std::set<Step::ptr> & newRunnable)
 {
-    if (finishedDrvs.find(drvPath) != finishedDrvs.end()) return 0;
+    if (finishedDrvs.find(drvPath) != finishedDrvs.end()) return nullptr;
 
     /* Check if the requested step already exists. If not, create a
        new step. In any case, make the step reachable from
@@ -516,7 +517,7 @@ Step::ptr State::createStep(ref<Store> destStore,
     std::map<DrvOutput, std::optional<StorePath>> paths;
     for (auto & [outputName, maybeOutputPath] : destStore->queryPartialDerivationOutputMap(drvPath, &*localStore)) {
         auto outputHash = outputHashes.at(outputName);
-        paths.insert({{outputHash, outputName}, maybeOutputPath});
+        paths.insert({{.drvHash=outputHash, .outputName=outputName}, maybeOutputPath});
     }
 
     auto missing = getMissingRemotePaths(destStore, paths);
@@ -560,7 +561,7 @@ Step::ptr State::createStep(ref<Store> destStore,
                 auto & path = *pathOpt;
 
                 try {
-                    time_t startTime = time(0);
+                    time_t startTime = time(nullptr);
 
                     if (localStore->isValidPath(path))
                         printInfo("copying output ‘%1%’ of ‘%2%’ from local store",
@@ -578,7 +579,7 @@ Step::ptr State::createStep(ref<Store> destStore,
                         StorePathSet { path },
                         NoRepair, CheckSigs, NoSubstitute);
 
-                    time_t stopTime = time(0);
+                    time_t stopTime = time(nullptr);
 
                     {
                         auto mc = startDbUpdate();
@@ -602,7 +603,7 @@ Step::ptr State::createStep(ref<Store> destStore,
     // FIXME: check whether all outputs are in the binary cache.
     if (valid) {
         finishedDrvs.insert(drvPath);
-        return 0;
+        return nullptr;
     }
 
     /* No, we need to build. */
@@ -610,7 +611,7 @@ Step::ptr State::createStep(ref<Store> destStore,
 
     /* Create steps for the dependencies. */
     for (auto & i : step->drv->inputDrvs.map) {
-        auto dep = createStep(destStore, conn, build, i.first, 0, step, finishedDrvs, newSteps, newRunnable);
+        auto dep = createStep(destStore, conn, build, i.first, nullptr, step, finishedDrvs, newSteps, newRunnable);
         if (dep) {
             auto step_(step->state.lock());
             step_->deps.insert(dep);
@@ -658,11 +659,11 @@ Jobset::ptr State::createJobset(pqxx::work & txn,
     auto res2 = txn.exec_params
         ("select s.startTime, s.stopTime from BuildSteps s join Builds b on build = id "
          "where s.startTime is not null and s.stopTime > $1 and jobset_id = $2",
-         time(0) - Jobset::schedulingWindow * 10,
+         time(nullptr) - Jobset::schedulingWindow * 10,
          jobsetID);
     for (auto const & row : res2) {
-        time_t startTime = row["startTime"].as<time_t>();
-        time_t stopTime = row["stopTime"].as<time_t>();
+        auto startTime = row["startTime"].as<time_t>();
+        auto stopTime = row["stopTime"].as<time_t>();
         jobset->addStep(startTime, stopTime - startTime);
     }
 
@@ -702,7 +703,7 @@ BuildOutput State::getBuildOutputCached(Connection & conn, nix::ref<nix::Store>
              "where finished = 1 and (buildStatus = 0 or buildStatus = 6) and path = $1",
              localStore->printStorePath(output));
         if (r.empty()) continue;
-        BuildID id = r[0][0].as<BuildID>();
+        auto id = r[0][0].as<BuildID>();
 
         printInfo("reusing build %d", id);
 
diff --git a/src/hydra-queue-runner/state.hh b/src/hydra-queue-runner/state.hh
index bc3241d7..84478bf6 100644
--- a/src/hydra-queue-runner/state.hh
+++ b/src/hydra-queue-runner/state.hh
@@ -8,6 +8,7 @@
 #include <queue>
 #include <regex>
 #include <semaphore>
+#include <utility>
 
 #include <prometheus/counter.h>
 #include <prometheus/gauge.h>
@@ -26,16 +27,16 @@
 #include "machines.hh"
 
 
-typedef unsigned int BuildID;
+using BuildID = unsigned int;
 
-typedef unsigned int JobsetID;
+using JobsetID = unsigned int;
 
-typedef std::chrono::time_point<std::chrono::system_clock> system_time;
+using system_time = std::chrono::time_point<std::chrono::system_clock>;
 
-typedef std::atomic<unsigned long> counter;
+using counter = std::atomic<unsigned long>;
 
 
-typedef enum {
+enum BuildStatus {
     bsSuccess = 0,
     bsFailed = 1,
     bsDepFailed = 2, // builds only
@@ -49,10 +50,10 @@ typedef enum {
     bsNarSizeLimitExceeded = 11,
     bsNotDeterministic = 12,
     bsBusy = 100, // not stored
-} BuildStatus;
+};
 
 
-typedef enum {
+enum StepState {
     ssPreparing = 1,
     ssConnecting = 10,
     ssSendingInputs = 20,
@@ -60,7 +61,7 @@ typedef enum {
     ssWaitingForLocalSlot = 35,
     ssReceivingOutputs = 40,
     ssPostProcessing = 50,
-} StepState;
+};
 
 
 struct RemoteResult
@@ -78,7 +79,7 @@ struct RemoteResult
     unsigned int overhead = 0;
     nix::Path logFile;
 
-    BuildStatus buildStatus() const
+    [[nodiscard]] BuildStatus buildStatus() const
     {
         return stepStatus == bsCachedFailure ? bsFailed : stepStatus;
     }
@@ -95,8 +96,8 @@ class Jobset
 {
 public:
 
-    typedef std::shared_ptr<Jobset> ptr;
-    typedef std::weak_ptr<Jobset> wptr;
+    using ptr = std::shared_ptr<Jobset>;
+    using wptr = std::weak_ptr<Jobset>;
 
     static const time_t schedulingWindow = static_cast<time_t>(24 * 60 * 60);
 
@@ -131,8 +132,8 @@ public:
 
 struct Build
 {
-    typedef std::shared_ptr<Build> ptr;
-    typedef std::weak_ptr<Build> wptr;
+    using ptr = std::shared_ptr<Build>;
+    using wptr = std::weak_ptr<Build>;
 
     BuildID id;
     nix::StorePath drvPath;
@@ -163,8 +164,8 @@ struct Build
 
 struct Step
 {
-    typedef std::shared_ptr<Step> ptr;
-    typedef std::weak_ptr<Step> wptr;
+    using ptr = std::shared_ptr<Step>;
+    using wptr = std::weak_ptr<Step>;
 
     nix::StorePath drvPath;
     std::unique_ptr<nix::Derivation> drv;
@@ -221,13 +222,8 @@ struct Step
 
     nix::Sync<State> state;
 
-    Step(const nix::StorePath & drvPath) : drvPath(drvPath)
+    Step(nix::StorePath  drvPath) : drvPath(std::move(drvPath))
     { }
-
-    ~Step()
-    {
-        //printMsg(lvlError, format("destroying step %1%") % drvPath);
-    }
 };
 
 
@@ -239,7 +235,7 @@ void visitDependencies(std::function<void(Step::ptr)> visitor, Step::ptr step);
 
 struct Machine : nix::Machine
 {
-    typedef std::shared_ptr<Machine> ptr;
+    using ptr = std::shared_ptr<Machine>;
 
     /* TODO Get rid of: `nix::Machine::storeUri` is normalized in a way
        we are not yet used to, but once we are, we don't need this. */
@@ -254,7 +250,7 @@ struct Machine : nix::Machine
     float speedFactorFloat = 1.0;
 
     struct State {
-        typedef std::shared_ptr<State> ptr;
+        using ptr = std::shared_ptr<State>;
         counter currentJobs{0};
         counter nrStepsDone{0};
         counter totalStepTime{0}; // total time for steps, including closure copying
@@ -358,22 +354,22 @@ private:
     bool useSubstitutes = false;
 
     /* The queued builds. */
-    typedef std::map<BuildID, Build::ptr> Builds;
+    using Builds = std::map<BuildID, Build::ptr>;
     nix::Sync<Builds> builds;
 
     /* The jobsets. */
-    typedef std::map<std::pair<std::string, std::string>, Jobset::ptr> Jobsets;
+    using Jobsets = std::map<std::pair<std::string, std::string>, Jobset::ptr>;
     nix::Sync<Jobsets> jobsets;
 
     /* All active or pending build steps (i.e. dependencies of the
        queued builds). Note that these are weak pointers. Steps are
        kept alive by being reachable from Builds or by being in
        progress. */
-    typedef std::map<nix::StorePath, Step::wptr> Steps;
+    using Steps = std::map<nix::StorePath, Step::wptr>;
     nix::Sync<Steps> steps;
 
     /* Build steps that have no unbuilt dependencies. */
-    typedef std::list<Step::wptr> Runnable;
+    using Runnable = std::list<Step::wptr>;
     nix::Sync<Runnable> runnable;
 
     /* CV for waking up the dispatcher. */
@@ -385,7 +381,7 @@ private:
 
     /* The build machines. */
     std::mutex machinesReadyLock;
-    typedef std::map<std::string, Machine::ptr> Machines;
+    using Machines = std::map<std::string, Machine::ptr>;
     nix::Sync<Machines> machines; // FIXME: use atomic_shared_ptr
 
     /* Throttler for CPU-bound local work. */
@@ -431,7 +427,7 @@ private:
 
     struct MachineReservation
     {
-        typedef std::shared_ptr<MachineReservation> ptr;
+        using ptr = std::shared_ptr<MachineReservation>;
         State & state;
         Step::ptr step;
         Machine::ptr machine;