diff --git a/src/ripple/app/misc/impl/ValidatorList.cpp b/src/ripple/app/misc/impl/ValidatorList.cpp
index 3d8dce509..09f774f8a 100644
--- a/src/ripple/app/misc/impl/ValidatorList.cpp
+++ b/src/ripple/app/misc/impl/ValidatorList.cpp
@@ -99,7 +99,7 @@ void
 ValidatorList::PublisherListStats::mergeDispositions(
     PublisherListStats const& src)
 {
-    for (auto const [disp, count] : src.dispositions)
+    for (auto const& [disp, count] : src.dispositions)
     {
         dispositions[disp] += count;
     }
diff --git a/src/ripple/app/misc/impl/ValidatorSite.cpp b/src/ripple/app/misc/impl/ValidatorSite.cpp
index e26ce7a87..34195a9d1 100644
--- a/src/ripple/app/misc/impl/ValidatorSite.cpp
+++ b/src/ripple/app/misc/impl/ValidatorSite.cpp
@@ -408,7 +408,7 @@ ValidatorSite::parseJsonResponse(
     sites_[siteIdx].lastRefreshStatus.emplace(
         Site::Status{clock_type::now(), applyResult.bestDisposition(), ""});
 
-    for (auto const [disp, count] : applyResult.dispositions)
+    for (auto const& [disp, count] : applyResult.dispositions)
     {
         switch (disp)
         {
diff --git a/src/ripple/overlay/impl/ConnectAttempt.cpp b/src/ripple/overlay/impl/ConnectAttempt.cpp
index c723b950b..911215d80 100644
--- a/src/ripple/overlay/impl/ConnectAttempt.cpp
+++ b/src/ripple/overlay/impl/ConnectAttempt.cpp
@@ -293,7 +293,7 @@ ConnectAttempt::processResponse()
         Json::Reader r;
         std::string s;
         s.reserve(boost::asio::buffer_size(response_.body().data()));
-        for (auto const& buffer : response_.body().data())
+        for (auto const buffer : response_.body().data())
             s.append(
                 boost::asio::buffer_cast<char const*>(buffer),
                 boost::asio::buffer_size(buffer));
diff --git a/src/ripple/overlay/impl/PeerImp.cpp b/src/ripple/overlay/impl/PeerImp.cpp
index 68f3d61d7..06221b6bb 100644
--- a/src/ripple/overlay/impl/PeerImp.cpp
+++ b/src/ripple/overlay/impl/PeerImp.cpp
@@ -2168,7 +2168,7 @@ PeerImp::onValidatorListMessage(
     }
 
     // Log based on all the results.
-    for (auto const [disp, count] : applyResult.dispositions)
+    for (auto const& [disp, count] : applyResult.dispositions)
     {
         switch (disp)
         {
diff --git a/src/ripple/rpc/impl/ServerHandlerImp.cpp b/src/ripple/rpc/impl/ServerHandlerImp.cpp
index b8d9567b0..fd056a346 100644
--- a/src/ripple/rpc/impl/ServerHandlerImp.cpp
+++ b/src/ripple/rpc/impl/ServerHandlerImp.cpp
@@ -264,7 +264,9 @@ buffers_to_string(ConstBufferSequence const& bs)
     using boost::asio::buffer_size;
     std::string s;
     s.reserve(buffer_size(bs));
-    for (auto const& b : bs)
+    // Use auto&& so the right thing happens whether bs returns a copy or
+    // a reference
+    for (auto&& b : bs)
         s.append(buffer_cast<char const*>(b), buffer_size(b));
     return s;
 }
diff --git a/src/ripple/server/SimpleWriter.h b/src/ripple/server/SimpleWriter.h
index 97819556b..03582c001 100644
--- a/src/ripple/server/SimpleWriter.h
+++ b/src/ripple/server/SimpleWriter.h
@@ -66,7 +66,7 @@ public:
         auto const& buf = sb_.data();
         std::vector<boost::asio::const_buffer> result;
         result.reserve(std::distance(buf.begin(), buf.end()));
-        for (auto const& b : buf)
+        for (auto const b : buf)
             result.push_back(b);
         return result;
     }
diff --git a/src/test/app/Check_test.cpp b/src/test/app/Check_test.cpp
index 3552d24bb..54e5d6d15 100644
--- a/src/test/app/Check_test.cpp
+++ b/src/test/app/Check_test.cpp
@@ -865,7 +865,7 @@ class Check_test : public beast::unit_test::suite
         // featureMultiSignReserve changes the reserve on a SignerList, so
         // check both before and after.
         FeatureBitset const allSupported{supported_amendments()};
-        for (auto const features :
+        for (auto const& features :
              {allSupported - featureMultiSignReserve,
               allSupported | featureMultiSignReserve})
         {
@@ -1514,7 +1514,7 @@ class Check_test : public beast::unit_test::suite
         // featureMultiSignReserve changes the reserve on a SignerList, so
         // check both before and after.
         FeatureBitset const allSupported{supported_amendments()};
-        for (auto const features :
+        for (auto const& features :
              {allSupported - featureMultiSignReserve,
               allSupported | featureMultiSignReserve})
         {
diff --git a/src/test/app/Offer_test.cpp b/src/test/app/Offer_test.cpp
index 8e6e55b4e..606b9f569 100644
--- a/src/test/app/Offer_test.cpp
+++ b/src/test/app/Offer_test.cpp
@@ -882,7 +882,7 @@ public:
         //
         // fix1578 changes the return code.  Verify expected behavior
         // without and with fix1578.
-        for (auto const tweakedFeatures :
+        for (auto const& tweakedFeatures :
              {features - fix1578, features | fix1578})
         {
             Env env{*this, tweakedFeatures};
diff --git a/src/test/csf/BasicNetwork_test.cpp b/src/test/csf/BasicNetwork_test.cpp
index 3ea3ef63a..f3b18216a 100644
--- a/src/test/csf/BasicNetwork_test.cpp
+++ b/src/test/csf/BasicNetwork_test.cpp
@@ -49,7 +49,7 @@ public:
             auto t = scheduler.in(1s, [&] { set.insert(0); });
             if (id == 0)
             {
-                for (auto const& link : net.links(this))
+                for (auto const link : net.links(this))
                     net.send(this, link.target, [&, to = link.target] {
                         to->receive(net, this, 1);
                     });
@@ -68,7 +68,7 @@ public:
             ++m;
             if (m < 5)
             {
-                for (auto const& link : net.links(this))
+                for (auto const link : net.links(this))
                     net.send(this, link.target, [&, mm = m, to = link.target] {
                         to->receive(net, this, mm);
                     });
diff --git a/src/test/csf/Peer.h b/src/test/csf/Peer.h
index 3b972493a..2f3ce1931 100644
--- a/src/test/csf/Peer.h
+++ b/src/test/csf/Peer.h
@@ -344,7 +344,7 @@ struct Peer
     bool
     trusts(PeerID const& oId)
     {
-        for (auto const& p : trustGraph.trustedPeers(this))
+        for (auto const p : trustGraph.trustedPeers(this))
             if (p->id == oId)
                 return true;
         return false;
@@ -404,7 +404,7 @@ struct Peer
 
         using namespace std::chrono_literals;
         SimDuration minDuration{10s};
-        for (auto const& link : net.links(this))
+        for (auto const link : net.links(this))
         {
             minDuration = std::min(minDuration, link.data.delay);
 
@@ -451,7 +451,7 @@ struct Peer
 
         using namespace std::chrono_literals;
         SimDuration minDuration{10s};
-        for (auto const& link : net.links(this))
+        for (auto const link : net.links(this))
         {
             minDuration = std::min(minDuration, link.data.delay);
             // Send a message to neighbors to find the tx set
@@ -741,7 +741,7 @@ struct Peer
     void
     send(BroadcastMesg<M> const& bm, PeerID from)
     {
-        for (auto const& link : net.links(this))
+        for (auto const link : net.links(this))
         {
             if (link.target->id != from && link.target->id != bm.origin)
             {
@@ -848,7 +848,7 @@ struct Peer
     getQuorumKeys()
     {
         hash_set<NodeKey_t> keys;
-        for (auto const& p : trustGraph.trustedPeers(this))
+        for (auto const p : trustGraph.trustedPeers(this))
             keys.insert(p->key);
         return {quorum, keys};
     }
diff --git a/src/test/csf/TrustGraph.h b/src/test/csf/TrustGraph.h
index c6c216053..31bb85340 100644
--- a/src/test/csf/TrustGraph.h
+++ b/src/test/csf/TrustGraph.h
@@ -126,7 +126,7 @@ public:
 
         using UNL = std::set<Peer>;
         std::set<UNL> unique;
-        for (Peer const& peer : graph_.outVertices())
+        for (Peer const peer : graph_.outVertices())
         {
             unique.emplace(
                 std::begin(trustedPeers(peer)), std::end(trustedPeers(peer)));
diff --git a/src/test/ledger/Invariants_test.cpp b/src/test/ledger/Invariants_test.cpp
index 4b0271e7e..f07f33922 100644
--- a/src/test/ledger/Invariants_test.cpp
+++ b/src/test/ledger/Invariants_test.cpp
@@ -75,7 +75,7 @@ class Invariants_test : public beast::unit_test::suite
             return;
 
         TER terActual = tesSUCCESS;
-        for (TER const terExpect : ters)
+        for (TER const& terExpect : ters)
         {
             terActual = ac.checkInvariants(terActual, fee);
             BEAST_EXPECT(terExpect == terActual);
diff --git a/src/test/rpc/NoRipple_test.cpp b/src/test/rpc/NoRipple_test.cpp
index 69c88d144..aa7358f77 100644
--- a/src/test/rpc/NoRipple_test.cpp
+++ b/src/test/rpc/NoRipple_test.cpp
@@ -84,7 +84,7 @@ public:
 
         // fix1578 changes the return code.  Verify expected behavior
         // without and with fix1578.
-        for (auto const tweakedFeatures :
+        for (auto const& tweakedFeatures :
              {features - fix1578, features | fix1578})
         {
             Env env(*this, tweakedFeatures);