diff --git a/src/libstore/nar-accessor.cc b/src/libstore/nar-accessor.cc
index 1a4936736..15b05fe25 100644
--- a/src/libstore/nar-accessor.cc
+++ b/src/libstore/nar-accessor.cc
@@ -161,7 +161,7 @@ struct NarAccessor : public SourceAccessor
     {
         NarMember * current = &root;
 
-        for (auto & i : path) {
+        for (const auto & i : path) {
             if (current->stat.type != Type::tDirectory) return nullptr;
             auto child = current->children.find(std::string(i));
             if (child == current->children.end()) return nullptr;
@@ -194,7 +194,7 @@ struct NarAccessor : public SourceAccessor
             throw Error("path '%1%' inside NAR file is not a directory", path);
 
         DirEntries res;
-        for (auto & child : i.children)
+        for (const auto & child : i.children)
             res.insert_or_assign(child.first, std::nullopt);
 
         return res;
@@ -259,7 +259,7 @@ json listNar(ref<SourceAccessor> accessor, const CanonPath & path, bool recurse)
         {
             obj["entries"] = json::object();
             json &res2 = obj["entries"];
-            for (auto & [name, type] : accessor->readDirectory(path)) {
+            for (const auto & [name, type] : accessor->readDirectory(path)) {
                 if (recurse) {
                     res2[name] = listNar(accessor, path + name, true);
                 } else
diff --git a/src/libstore/nar-accessor.hh b/src/libstore/nar-accessor.hh
index 433774524..0043897c6 100644
--- a/src/libstore/nar-accessor.hh
+++ b/src/libstore/nar-accessor.hh
@@ -25,7 +25,7 @@ ref<SourceAccessor> makeNarAccessor(Source & source);
  * readFile() method of the accessor to get the contents of files
  * inside the NAR.
  */
-typedef std::function<std::string(uint64_t, uint64_t)> GetNarBytes;
+using GetNarBytes = std::function<std::string(uint64_t, uint64_t)>;
 
 ref<SourceAccessor> makeLazyNarAccessor(
     const std::string & listing,
diff --git a/src/libstore/nar-info.cc b/src/libstore/nar-info.cc
index ae2223fb0..1060a6c8b 100644
--- a/src/libstore/nar-info.cc
+++ b/src/libstore/nar-info.cc
@@ -38,12 +38,12 @@ NarInfo::NarInfo(const Store & store, const std::string & s, const std::string &
     while (pos < s.size()) {
 
         size_t colon = s.find(':', pos);
-        if (colon == std::string::npos) throw corrupt("expecting ':'");
+        if (colon == s.npos) throw corrupt("expecting ':'");
 
         std::string name(s, pos, colon - pos);
 
         size_t eol = s.find('\n', colon + 2);
-        if (eol == std::string::npos) throw corrupt("expecting '\\n'");
+        if (eol == s.npos) throw corrupt("expecting '\\n'");
 
         std::string value(s, colon + 2, eol - colon - 2);
 
diff --git a/src/libstore/nar-info.hh b/src/libstore/nar-info.hh
index cec65ff70..fd538a7cd 100644
--- a/src/libstore/nar-info.hh
+++ b/src/libstore/nar-info.hh
@@ -17,10 +17,10 @@ struct NarInfo : ValidPathInfo
     uint64_t fileSize = 0;
 
     NarInfo() = delete;
-    NarInfo(const Store & store, std::string && name, ContentAddressWithReferences && ca, Hash narHash)
+    NarInfo(const Store & store, std::string name, ContentAddressWithReferences ca, Hash narHash)
         : ValidPathInfo(store, std::move(name), std::move(ca), narHash)
     { }
-    NarInfo(StorePath && path, Hash narHash) : ValidPathInfo(std::move(path), narHash) { }
+    NarInfo(StorePath path, Hash narHash) : ValidPathInfo(std::move(path), narHash) { }
     NarInfo(const ValidPathInfo & info) : ValidPathInfo(info) { }
     NarInfo(const Store & store, const std::string & s, const std::string & whence);
 
diff --git a/src/libstore/worker-protocol.cc b/src/libstore/worker-protocol.cc
index 1d202f8d1..7118558b1 100644
--- a/src/libstore/worker-protocol.cc
+++ b/src/libstore/worker-protocol.cc
@@ -31,14 +31,14 @@ std::optional<TrustedFlag> WorkerProto::Serialise<std::optional<TrustedFlag>>::r
 void WorkerProto::Serialise<std::optional<TrustedFlag>>::write(const Store & store, WorkerProto::WriteConn conn, const std::optional<TrustedFlag> & optTrusted)
 {
     if (!optTrusted)
-        conn.to << (uint8_t)0;
+        conn.to << uint8_t{0};
     else {
         switch (*optTrusted) {
         case Trusted:
-            conn.to << (uint8_t)1;
+            conn.to << uint8_t{1};
             break;
         case NotTrusted:
-            conn.to << (uint8_t)2;
+            conn.to << uint8_t{2};
             break;
         default:
             assert(false);
@@ -101,7 +101,7 @@ void WorkerProto::Serialise<KeyedBuildResult>::write(const Store & store, Worker
 BuildResult WorkerProto::Serialise<BuildResult>::read(const Store & store, WorkerProto::ReadConn conn)
 {
     BuildResult res;
-    res.status = (BuildResult::Status) readInt(conn.from);
+    res.status = static_cast<BuildResult::Status>(readInt(conn.from));
     conn.from >> res.errorMsg;
     if (GET_PROTOCOL_MINOR(conn.version) >= 29) {
         conn.from
diff --git a/src/libstore/worker-protocol.hh b/src/libstore/worker-protocol.hh
index dcd54ad16..25d544ba7 100644
--- a/src/libstore/worker-protocol.hh
+++ b/src/libstore/worker-protocol.hh
@@ -171,7 +171,7 @@ enum struct WorkerProto::Op : uint64_t
  */
 inline Sink & operator << (Sink & sink, WorkerProto::Op op)
 {
-    return sink << (uint64_t) op;
+    return sink << static_cast<uint64_t>(op);
 }
 
 /**
@@ -181,7 +181,7 @@ inline Sink & operator << (Sink & sink, WorkerProto::Op op)
  */
 inline std::ostream & operator << (std::ostream & s, WorkerProto::Op op)
 {
-    return s << (uint64_t) op;
+    return s << static_cast<uint64_t>(op);
 }
 
 /**