about summary refs log tree commit diff
diff options
context:
space:
mode:
-rw-r--r--third_party/nix/src/build-remote/build-remote.cc6
-rw-r--r--third_party/nix/src/cpptoml/cpptoml.h4
-rw-r--r--third_party/nix/src/libexpr/attr-path.cc2
-rw-r--r--third_party/nix/src/libexpr/common-eval-args.cc6
-rw-r--r--third_party/nix/src/libexpr/eval.cc41
-rw-r--r--third_party/nix/src/libexpr/eval.hh12
-rw-r--r--third_party/nix/src/libexpr/get-drvs.cc14
-rw-r--r--third_party/nix/src/libexpr/get-drvs.hh6
-rw-r--r--third_party/nix/src/libexpr/names.cc12
-rw-r--r--third_party/nix/src/libexpr/names.hh6
-rw-r--r--third_party/nix/src/libexpr/nixexpr.cc13
-rw-r--r--third_party/nix/src/libexpr/nixexpr.hh43
-rw-r--r--third_party/nix/src/libexpr/parser.y39
-rw-r--r--third_party/nix/src/libexpr/primops.cc29
-rw-r--r--third_party/nix/src/libexpr/primops/context.cc10
-rw-r--r--third_party/nix/src/libmain/common-args.cc2
-rw-r--r--third_party/nix/src/libmain/common-args.hh4
-rw-r--r--third_party/nix/src/libmain/shared.cc18
-rw-r--r--third_party/nix/src/libmain/shared.hh18
-rw-r--r--third_party/nix/src/libstore/binary-cache-store.cc5
-rw-r--r--third_party/nix/src/libstore/binary-cache-store.hh6
-rw-r--r--third_party/nix/src/libstore/build.cc131
-rw-r--r--third_party/nix/src/libstore/builtins/buildenv.cc4
-rw-r--r--third_party/nix/src/libstore/builtins/fetchurl.cc2
-rw-r--r--third_party/nix/src/libstore/crypto.cc8
-rw-r--r--third_party/nix/src/libstore/derivations.cc60
-rw-r--r--third_party/nix/src/libstore/derivations.hh28
-rw-r--r--third_party/nix/src/libstore/download.cc29
-rw-r--r--third_party/nix/src/libstore/download.hh2
-rw-r--r--third_party/nix/src/libstore/gc.cc38
-rw-r--r--third_party/nix/src/libstore/globals.cc2
-rw-r--r--third_party/nix/src/libstore/globals.hh2
-rw-r--r--third_party/nix/src/libstore/http-binary-cache-store.cc2
-rw-r--r--third_party/nix/src/libstore/legacy-ssh-store.cc10
-rw-r--r--third_party/nix/src/libstore/local-fs-store.cc11
-rw-r--r--third_party/nix/src/libstore/local-store.cc43
-rw-r--r--third_party/nix/src/libstore/local-store.hh14
-rw-r--r--third_party/nix/src/libstore/machines.cc24
-rw-r--r--third_party/nix/src/libstore/machines.hh14
-rw-r--r--third_party/nix/src/libstore/nar-accessor.cc6
-rw-r--r--third_party/nix/src/libstore/nar-info.cc2
-rw-r--r--third_party/nix/src/libstore/optimise-store.cc4
-rw-r--r--third_party/nix/src/libstore/pathlocks.cc4
-rw-r--r--third_party/nix/src/libstore/pathlocks.hh6
-rw-r--r--third_party/nix/src/libstore/profiles.cc22
-rw-r--r--third_party/nix/src/libstore/profiles.hh8
-rw-r--r--third_party/nix/src/libstore/references.cc30
-rw-r--r--third_party/nix/src/libstore/remote-store.cc14
-rw-r--r--third_party/nix/src/libstore/remote-store.hh6
-rw-r--r--third_party/nix/src/libstore/s3-binary-cache-store.cc7
-rw-r--r--third_party/nix/src/libstore/sqlite.cc2
-rw-r--r--third_party/nix/src/libstore/store-api.cc64
-rw-r--r--third_party/nix/src/libstore/store-api.hh52
-rw-r--r--third_party/nix/src/libutil/archive.cc30
-rw-r--r--third_party/nix/src/libutil/archive.hh2
-rw-r--r--third_party/nix/src/libutil/args.cc14
-rw-r--r--third_party/nix/src/libutil/args.hh4
-rw-r--r--third_party/nix/src/libutil/config.cc14
-rw-r--r--third_party/nix/src/libutil/hash.cc28
-rw-r--r--third_party/nix/src/libutil/hash.hh10
-rw-r--r--third_party/nix/src/libutil/serialise.cc6
-rw-r--r--third_party/nix/src/libutil/serialise.hh12
-rw-r--r--third_party/nix/src/libutil/types.hh26
-rw-r--r--third_party/nix/src/libutil/util.cc121
-rw-r--r--third_party/nix/src/libutil/util.hh79
-rw-r--r--third_party/nix/src/libutil/xml-writer.cc7
-rw-r--r--third_party/nix/src/libutil/xml-writer.hh10
-rw-r--r--third_party/nix/src/nix-build/nix-build.cc14
-rw-r--r--third_party/nix/src/nix-channel/nix-channel.cc14
-rw-r--r--third_party/nix/src/nix-collect-garbage/nix-collect-garbage.cc2
-rw-r--r--third_party/nix/src/nix-daemon/nix-daemon.cc34
-rw-r--r--third_party/nix/src/nix-env/nix-env.cc108
-rw-r--r--third_party/nix/src/nix-env/user-env.cc2
-rw-r--r--third_party/nix/src/nix-env/user-env.hh2
-rw-r--r--third_party/nix/src/nix-instantiate/nix-instantiate.cc2
-rw-r--r--third_party/nix/src/nix-prefetch-url/nix-prefetch-url.cc25
-rw-r--r--third_party/nix/src/nix-store/dotgraph.cc26
-rw-r--r--third_party/nix/src/nix-store/graphml.cc12
-rw-r--r--third_party/nix/src/nix-store/nix-store.cc36
-rw-r--r--third_party/nix/src/nix/command.cc5
-rw-r--r--third_party/nix/src/nix/command.hh4
-rw-r--r--third_party/nix/src/nix/hash.cc2
-rw-r--r--third_party/nix/src/nix/main.cc2
-rw-r--r--third_party/nix/src/nix/repl.cc72
-rw-r--r--third_party/nix/src/nix/why-depends.cc14
85 files changed, 862 insertions, 824 deletions
diff --git a/third_party/nix/src/build-remote/build-remote.cc b/third_party/nix/src/build-remote/build-remote.cc
index 9403d3c35e99..351c660db1e9 100644
--- a/third_party/nix/src/build-remote/build-remote.cc
+++ b/third_party/nix/src/build-remote/build-remote.cc
@@ -30,7 +30,7 @@ std::string escapeUri(std::string uri) {
   return uri;
 }
 
-static string currentLoad;
+static std::string currentLoad;
 
 static AutoCloseFD openSlotLock(const Machine& m, unsigned long long slot) {
   return openLockFile(fmt("%s/%s-%d", currentLoad, escapeUri(m.storeUri), slot),
@@ -86,8 +86,8 @@ static int _main(int argc, char* argv[]) {
       return 0;
     }
 
-    string drvPath;
-    string storeUri;
+    std::string drvPath;
+    std::string storeUri;
 
     while (true) {
       try {
diff --git a/third_party/nix/src/cpptoml/cpptoml.h b/third_party/nix/src/cpptoml/cpptoml.h
index 5a00da3b4cda..150b53ff863c 100644
--- a/third_party/nix/src/cpptoml/cpptoml.h
+++ b/third_party/nix/src/cpptoml/cpptoml.h
@@ -852,7 +852,7 @@ class array : public base
     }
 
     /**
-     * Obtains a option<vector<T>>. The option will be empty if the array
+     * Obtains a option<std::vector<T>>. The option will be empty if the array
      * contains values that are not of type T.
      */
     template <class T>
@@ -1041,7 +1041,7 @@ inline std::shared_ptr<array> make_element<array>()
 } // namespace detail
 
 /**
- * Obtains a option<vector<T>>. The option will be empty if the array
+ * Obtains a option<std::vector<T>>. The option will be empty if the array
  * contains values that are not of type T.
  */
 template <>
diff --git a/third_party/nix/src/libexpr/attr-path.cc b/third_party/nix/src/libexpr/attr-path.cc
index 1815b5e510d3..628b58c1b1e3 100644
--- a/third_party/nix/src/libexpr/attr-path.cc
+++ b/third_party/nix/src/libexpr/attr-path.cc
@@ -8,7 +8,7 @@ namespace nix {
 static Strings parseAttrPath(const std::string& s) {
   Strings res;
   std::string cur;
-  string::const_iterator i = s.begin();
+  std::string::const_iterator i = s.begin();
   while (i != s.end()) {
     if (*i == '.') {
       res.push_back(cur);
diff --git a/third_party/nix/src/libexpr/common-eval-args.cc b/third_party/nix/src/libexpr/common-eval-args.cc
index 2059d5374195..19271f2cc582 100644
--- a/third_party/nix/src/libexpr/common-eval-args.cc
+++ b/third_party/nix/src/libexpr/common-eval-args.cc
@@ -37,10 +37,10 @@ Bindings* MixEvalArgs::getAutoArgs(EvalState& state) {
   for (auto& i : autoArgs) {
     Value* v = state.allocValue();
     if (i.second[0] == 'E') {
-      state.mkThunk_(
-          *v, state.parseExprFromString(string(i.second, 1), absPath(".")));
+      state.mkThunk_(*v, state.parseExprFromString(std::string(i.second, 1),
+                                                   absPath(".")));
     } else {
-      mkString(*v, string(i.second, 1));
+      mkString(*v, std::string(i.second, 1));
     }
     res->push_back(Attr(state.symbols.Create(i.first), v));
   }
diff --git a/third_party/nix/src/libexpr/eval.cc b/third_party/nix/src/libexpr/eval.cc
index 60d3cd012df8..d93f39bba4fe 100644
--- a/third_party/nix/src/libexpr/eval.cc
+++ b/third_party/nix/src/libexpr/eval.cc
@@ -136,7 +136,7 @@ const Value* getPrimOp(const Value& v) {
   return primOp;
 }
 
-string showType(const Value& v) {
+std::string showType(const Value& v) {
   switch (v.type) {
     case tInt:
       return "an integer";
@@ -163,10 +163,10 @@ string showType(const Value& v) {
     case tBlackhole:
       return "a black hole";
     case tPrimOp:
-      return fmt("the built-in function '%s'", string(v.primOp->name));
+      return fmt("the built-in function '%s'", std::string(v.primOp->name));
     case tPrimOpApp:
       return fmt("the partially applied built-in function '%s'",
-                 string(getPrimOp(v)->primOp->name));
+                 std::string(getPrimOp(v)->primOp->name));
     case tExternal:
       return v.external->showType();
     case tFloat:
@@ -456,7 +456,8 @@ Value* EvalState::addConstant(const std::string& name, Value& v) {
   *v2 = v;
   staticBaseEnv.vars[symbols.Create(name)] = baseEnvDispl;
   baseEnv.values[baseEnvDispl++] = v2;
-  std::string name2 = string(name, 0, 2) == "__" ? string(name, 2) : name;
+  std::string name2 =
+      std::string(name, 0, 2) == "__" ? std::string(name, 2) : name;
   baseEnv.values[0]->attrs->push_back(Attr(symbols.Create(name2), v2));
   return v2;
 }
@@ -469,7 +470,8 @@ Value* EvalState::addPrimOp(const std::string& name, size_t arity,
     return addConstant(name, v);
   }
   Value* v = allocValue();
-  std::string name2 = string(name, 0, 2) == "__" ? string(name, 2) : name;
+  std::string name2 =
+      std::string(name, 0, 2) == "__" ? std::string(name, 2) : name;
   Symbol sym = symbols.Create(name2);
   v->type = tPrimOp;
   v->primOp = new PrimOp(primOp, arity, sym);
@@ -1423,7 +1425,7 @@ void EvalState::forceFunction(Value& v, const Pos& pos) {
   }
 }
 
-string EvalState::forceString(Value& v, const Pos& pos) {
+std::string EvalState::forceString(Value& v, const Pos& pos) {
   forceValue(v, pos);
   if (v.type != tString) {
     if (pos) {
@@ -1433,7 +1435,7 @@ string EvalState::forceString(Value& v, const Pos& pos) {
       throwTypeError("value is %1% while a string was expected", v);
     }
   }
-  return string(v.string.s);
+  return std::string(v.string.s);
 }
 
 void copyContext(const Value& v, PathSet& context) {
@@ -1444,13 +1446,13 @@ void copyContext(const Value& v, PathSet& context) {
   }
 }
 
-string EvalState::forceString(Value& v, PathSet& context, const Pos& pos) {
+std::string EvalState::forceString(Value& v, PathSet& context, const Pos& pos) {
   std::string s = forceString(v, pos);
   copyContext(v, context);
   return s;
 }
 
-string EvalState::forceStringNoCtx(Value& v, const Pos& pos) {
+std::string EvalState::forceStringNoCtx(Value& v, const Pos& pos) {
   std::string s = forceString(v, pos);
   if (v.string.context != nullptr) {
     if (pos) {
@@ -1483,10 +1485,10 @@ bool EvalState::isDerivation(Value& v) {
   return strcmp(i->second.value->string.s, "derivation") == 0;
 }
 
-std::optional<string> EvalState::tryAttrsToString(const Pos& pos, Value& v,
-                                                  PathSet& context,
-                                                  bool coerceMore,
-                                                  bool copyToStore) {
+std::optional<std::string> EvalState::tryAttrsToString(const Pos& pos, Value& v,
+                                                       PathSet& context,
+                                                       bool coerceMore,
+                                                       bool copyToStore) {
   auto i = v.attrs->find(sToString);
   if (i != v.attrs->end()) {
     Value v1;
@@ -1497,8 +1499,9 @@ std::optional<string> EvalState::tryAttrsToString(const Pos& pos, Value& v,
   return {};
 }
 
-string EvalState::coerceToString(const Pos& pos, Value& v, PathSet& context,
-                                 bool coerceMore, bool copyToStore) {
+std::string EvalState::coerceToString(const Pos& pos, Value& v,
+                                      PathSet& context, bool coerceMore,
+                                      bool copyToStore) {
   forceValue(v);
 
   std::string s;
@@ -1569,7 +1572,7 @@ string EvalState::coerceToString(const Pos& pos, Value& v, PathSet& context,
   throwTypeError("cannot coerce %1% to a string, at %2%", v, pos);
 }
 
-string EvalState::copyPathToStore(PathSet& context, const Path& path) {
+std::string EvalState::copyPathToStore(PathSet& context, const Path& path) {
   if (nix::isDerivation(path)) {
     throwEvalError("file names are not allowed to end in '%1%'", drvExtension);
   }
@@ -1931,9 +1934,9 @@ size_t valueSize(Value& v) {
   return doValue(v);
 }
 
-string ExternalValueBase::coerceToString(const Pos& pos, PathSet& context,
-                                         bool copyMore,
-                                         bool copyToStore) const {
+std::string ExternalValueBase::coerceToString(const Pos& pos, PathSet& context,
+                                              bool copyMore,
+                                              bool copyToStore) const {
   throw TypeError(format("cannot coerce %1% to a string, at %2%") % showType() %
                   pos);
 }
diff --git a/third_party/nix/src/libexpr/eval.hh b/third_party/nix/src/libexpr/eval.hh
index 531294c93ca2..f13e8553d14b 100644
--- a/third_party/nix/src/libexpr/eval.hh
+++ b/third_party/nix/src/libexpr/eval.hh
@@ -180,10 +180,10 @@ class EvalState {
      set with attribute `type = "derivation"'). */
   bool isDerivation(Value& v);
 
-  std::optional<string> tryAttrsToString(const Pos& pos, Value& v,
-                                         PathSet& context,
-                                         bool coerceMore = false,
-                                         bool copyToStore = true);
+  std::optional<std::string> tryAttrsToString(const Pos& pos, Value& v,
+                                              PathSet& context,
+                                              bool coerceMore = false,
+                                              bool copyToStore = true);
 
   /* String coercion.  Converts strings, paths and derivations to a
      string.  If `coerceMore' is set, also converts nulls, integers,
@@ -295,11 +295,11 @@ class EvalState {
 };
 
 /* Return a string representing the type of the value `v'. */
-string showType(const Value& v);
+std::string showType(const Value& v);
 
 /* Decode a context string ‘!<name>!<path>’ into a pair <path,
    name>. */
-std::pair<string, string> decodeContext(const std::string& s);
+std::pair<std::string, std::string> decodeContext(const std::string& s);
 
 /* If `path' refers to a directory, then append "/default.nix". */
 Path resolveExprPath(Path path);
diff --git a/third_party/nix/src/libexpr/get-drvs.cc b/third_party/nix/src/libexpr/get-drvs.cc
index 6d4ad33be063..bc40ec3fef6c 100644
--- a/third_party/nix/src/libexpr/get-drvs.cc
+++ b/third_party/nix/src/libexpr/get-drvs.cc
@@ -44,7 +44,7 @@ DrvInfo::DrvInfo(EvalState& state, const ref<Store>& store,
   outPath = i->second.path;
 }
 
-string DrvInfo::queryName() const {
+std::string DrvInfo::queryName() const {
   if (name.empty() && (attrs != nullptr)) {
     auto i = attrs->find(state->sName);
     if (i == attrs->end()) {
@@ -55,7 +55,7 @@ string DrvInfo::queryName() const {
   return name;
 }
 
-string DrvInfo::querySystem() const {
+std::string DrvInfo::querySystem() const {
   if (system.empty() && (attrs != nullptr)) {
     auto i = attrs->find(state->sSystem);
     system = i == attrs->end()
@@ -65,7 +65,7 @@ string DrvInfo::querySystem() const {
   return system;
 }
 
-string DrvInfo::queryDrvPath() const {
+std::string DrvInfo::queryDrvPath() const {
   if (drvPath.empty() && (attrs != nullptr)) {
     Bindings::iterator i = attrs->find(state->sDrvPath);
     PathSet context;
@@ -76,7 +76,7 @@ string DrvInfo::queryDrvPath() const {
   return drvPath;
 }
 
-string DrvInfo::queryOutPath() const {
+std::string DrvInfo::queryOutPath() const {
   if (outPath.empty() && (attrs != nullptr)) {
     Bindings::iterator i = attrs->find(state->sOutPath);
     PathSet context;
@@ -149,7 +149,7 @@ DrvInfo::Outputs DrvInfo::queryOutputs(bool onlyOutputsToInstall) {
   return result;
 }
 
-string DrvInfo::queryOutputName() const {
+std::string DrvInfo::queryOutputName() const {
   if (outputName.empty() && (attrs != nullptr)) {
     Bindings::iterator i = attrs->find(state->sOutputName);
     outputName =
@@ -223,7 +223,7 @@ Value* DrvInfo::queryMeta(const std::string& name) {
   return a->second.value;
 }
 
-string DrvInfo::queryMetaString(const std::string& name) {
+std::string DrvInfo::queryMetaString(const std::string& name) {
   Value* v = queryMeta(name);
   if ((v == nullptr) || v->type != tString) {
     return "";
@@ -308,7 +308,7 @@ void DrvInfo::setMeta(const std::string& name, Value* v) {
 }
 
 /* Cache for already considered attrsets. */
-using Done = set<Bindings*>;
+using Done = std::set<Bindings*>;
 
 /* Evaluate value `v'.  If it evaluates to a set of type `derivation',
    then put information about it in `drvs' (unless it's already in `done').
diff --git a/third_party/nix/src/libexpr/get-drvs.hh b/third_party/nix/src/libexpr/get-drvs.hh
index 3da23194616e..a0840ee9b280 100644
--- a/third_party/nix/src/libexpr/get-drvs.hh
+++ b/third_party/nix/src/libexpr/get-drvs.hh
@@ -9,7 +9,7 @@ namespace nix {
 
 struct DrvInfo {
  public:
-  typedef std::map<string, Path> Outputs;
+  typedef std::map<std::string, Path> Outputs;
 
  private:
   EvalState* state;
@@ -68,9 +68,9 @@ struct DrvInfo {
 };
 
 #if HAVE_BOEHMGC
-typedef list<DrvInfo, traceable_allocator<DrvInfo> > DrvInfos;
+typedef std::list<DrvInfo, traceable_allocator<DrvInfo> > DrvInfos;
 #else
-typedef list<DrvInfo> DrvInfos;
+typedef std::list<DrvInfo> DrvInfos;
 #endif
 
 /* If value `v' denotes a derivation, return a DrvInfo object
diff --git a/third_party/nix/src/libexpr/names.cc b/third_party/nix/src/libexpr/names.cc
index ac8150532f25..20c326776cb7 100644
--- a/third_party/nix/src/libexpr/names.cc
+++ b/third_party/nix/src/libexpr/names.cc
@@ -18,8 +18,8 @@ DrvName::DrvName(const std::string& s) : hits(0) {
   for (unsigned int i = 0; i < s.size(); ++i) {
     /* !!! isalpha/isdigit are affected by the locale. */
     if (s[i] == '-' && i + 1 < s.size() && (isalpha(s[i + 1]) == 0)) {
-      name = string(s, 0, i);
-      version = string(s, i + 1);
+      name = std::string(s, 0, i);
+      version = std::string(s, i + 1);
       break;
     }
   }
@@ -37,8 +37,8 @@ bool DrvName::matches(DrvName& n) {
   return !(!version.empty() && version != n.version);
 }
 
-string nextComponent(string::const_iterator& p,
-                     const string::const_iterator end) {
+std::string nextComponent(std::string::const_iterator& p,
+                          const std::string::const_iterator end) {
   /* Skip any dots and dashes (component separators). */
   while (p != end && (*p == '.' || *p == '-')) {
     ++p;
@@ -91,8 +91,8 @@ static bool componentsLT(const std::string& c1, const std::string& c2) {
 }
 
 int compareVersions(const std::string& v1, const std::string& v2) {
-  string::const_iterator p1 = v1.begin();
-  string::const_iterator p2 = v2.begin();
+  std::string::const_iterator p1 = v1.begin();
+  std::string::const_iterator p2 = v2.begin();
 
   while (p1 != v1.end() || p2 != v2.end()) {
     std::string c1 = nextComponent(p1, v1.end());
diff --git a/third_party/nix/src/libexpr/names.hh b/third_party/nix/src/libexpr/names.hh
index e2ddb5cb993e..521740152ca2 100644
--- a/third_party/nix/src/libexpr/names.hh
+++ b/third_party/nix/src/libexpr/names.hh
@@ -21,10 +21,10 @@ struct DrvName {
   std::unique_ptr<std::regex> regex;
 };
 
-typedef list<DrvName> DrvNames;
+typedef std::list<DrvName> DrvNames;
 
-string nextComponent(string::const_iterator& p,
-                     const string::const_iterator end);
+std::string nextComponent(std::string::const_iterator& p,
+                          const std::string::const_iterator end);
 int compareVersions(const std::string& v1, const std::string& v2);
 DrvNames drvNamesFromArgs(const Strings& opArgs);
 
diff --git a/third_party/nix/src/libexpr/nixexpr.cc b/third_party/nix/src/libexpr/nixexpr.cc
index 3d454d266ff0..ef4a75ed8d5b 100644
--- a/third_party/nix/src/libexpr/nixexpr.cc
+++ b/third_party/nix/src/libexpr/nixexpr.cc
@@ -16,7 +16,7 @@ std::ostream& operator<<(std::ostream& str, const Expr& e) {
 
 static void showString(std::ostream& str, const std::string& s) {
   str << '"';
-  for (auto c : (string)s) {
+  for (auto c : (std::string)s) {
     if (c == '"' || c == '\\' || c == '$') {
       str << "\\" << c;
     } else if (c == '\n') {
@@ -188,14 +188,14 @@ std::ostream& operator<<(std::ostream& str, const Pos& pos) {
   if (!pos) {
     str << "undefined position";
   } else {
-    str << (format(ANSI_BOLD "%1%" ANSI_NORMAL ":%2%:%3%") % (string)pos.file %
-            pos.line % pos.column)
+    str << (format(ANSI_BOLD "%1%" ANSI_NORMAL ":%2%:%3%") %
+            (std::string)pos.file % pos.line % pos.column)
                .str();
   }
   return str;
 }
 
-string showAttrPath(const AttrPath& attrPath) {
+std::string showAttrPath(const AttrPath& attrPath) {
   std::ostringstream out;
   bool first = true;
   for (auto& i : attrPath) {
@@ -407,9 +407,10 @@ void ExprLambda::setName(Symbol& name) {
   body->setName(name);
 }
 
-string ExprLambda::showNamePos() const {
+std::string ExprLambda::showNamePos() const {
   return (format("%1% at %2%") %
-          (name.set() ? "'" + (string)name + "'" : "anonymous function") % pos)
+          (name.set() ? "'" + (std::string)name + "'" : "anonymous function") %
+          pos)
       .str();
 }
 
diff --git a/third_party/nix/src/libexpr/nixexpr.hh b/third_party/nix/src/libexpr/nixexpr.hh
index 3ac651c94548..8817fbc9ddb8 100644
--- a/third_party/nix/src/libexpr/nixexpr.hh
+++ b/third_party/nix/src/libexpr/nixexpr.hh
@@ -8,15 +8,18 @@
 
 namespace nix {
 
-MakeError(EvalError, Error) MakeError(ParseError, Error)
-    MakeError(AssertionError, EvalError) MakeError(ThrownError, AssertionError)
-        MakeError(Abort, EvalError) MakeError(TypeError, EvalError)
-            MakeError(UndefinedVarError, Error)
-                MakeError(RestrictedPathError, Error)
-
-    /* Position objects. */
-
-    struct Pos {
+MakeError(EvalError, Error);
+MakeError(ParseError, Error);
+MakeError(AssertionError, EvalError);
+MakeError(ThrownError, AssertionError);
+MakeError(Abort, EvalError);
+MakeError(TypeError, EvalError);
+MakeError(UndefinedVarError, Error);
+MakeError(RestrictedPathError, Error);
+
+/* Position objects. */
+
+struct Pos {
   Symbol file;
   unsigned int line, column;
   Pos() : line(0), column(0){};
@@ -30,7 +33,7 @@ MakeError(EvalError, Error) MakeError(ParseError, Error)
     if (!p2.line) {
       return false;
     }
-    int d = ((string)file).compare((string)p2.file);
+    int d = ((std::string)file).compare((std::string)p2.file);
     if (d < 0) {
       return true;
     }
@@ -66,7 +69,7 @@ struct AttrName {
 
 typedef std::vector<AttrName> AttrPath;
 
-string showAttrPath(const AttrPath& attrPath);
+std::string showAttrPath(const AttrPath& attrPath);
 
 /* Abstract syntax of Nix expressions. */
 
@@ -297,16 +300,20 @@ struct ExprOpNot : Expr {
     void eval(EvalState& state, Env& env, Value& v);                       \
   };
 
-MakeBinOp(ExprApp, "") MakeBinOp(ExprOpEq, "==") MakeBinOp(ExprOpNEq, "!=")
-    MakeBinOp(ExprOpAnd, "&&") MakeBinOp(ExprOpOr, "||")
-        MakeBinOp(ExprOpImpl, "->") MakeBinOp(ExprOpUpdate, "//")
-            MakeBinOp(ExprOpConcatLists, "++")
+MakeBinOp(ExprApp, "");
+MakeBinOp(ExprOpEq, "==");
+MakeBinOp(ExprOpNEq, "!=");
+MakeBinOp(ExprOpAnd, "&&");
+MakeBinOp(ExprOpOr, "||");
+MakeBinOp(ExprOpImpl, "->");
+MakeBinOp(ExprOpUpdate, "//");
+MakeBinOp(ExprOpConcatLists, "++");
 
-                struct ExprConcatStrings : Expr {
+struct ExprConcatStrings : Expr {
   Pos pos;
   bool forceString;
-  vector<Expr*>* es;
-  ExprConcatStrings(const Pos& pos, bool forceString, vector<Expr*>* es)
+  std::vector<Expr*>* es;
+  ExprConcatStrings(const Pos& pos, bool forceString, std::vector<Expr*>* es)
       : pos(pos), forceString(forceString), es(es){};
   COMMON_METHODS
 };
diff --git a/third_party/nix/src/libexpr/parser.y b/third_party/nix/src/libexpr/parser.y
index bd62a7fd0f52..9ba053ee7b12 100644
--- a/third_party/nix/src/libexpr/parser.y
+++ b/third_party/nix/src/libexpr/parser.y
@@ -146,7 +146,7 @@ static void addFormal(const Pos & pos, Formals * formals, const Formal & formal)
 }
 
 
-static Expr * stripIndentation(const Pos & pos, SymbolTable & symbols, vector<Expr *> & es)
+static Expr * stripIndentation(const Pos & pos, SymbolTable & symbols, std::vector<Expr *> & es)
 {
     if (es.empty()) { return new ExprString(symbols.Create("")); }
 
@@ -186,11 +186,11 @@ static Expr * stripIndentation(const Pos & pos, SymbolTable & symbols, vector<Ex
     }
 
     /* Strip spaces from each line. */
-    vector<Expr *> * es2 = new vector<Expr *>;
+    std::vector<Expr *> * es2 = new std::vector<Expr *>;
     atStartOfLine = true;
     size_t curDropped = 0;
     size_t n = es.size();
-    for (vector<Expr *>::iterator i = es.begin(); i != es.end(); ++i, --n) {
+    for (std::vector<Expr *>::iterator i = es.begin(); i != es.end(); ++i, --n) {
         ExprIndStr * e = dynamic_cast<ExprIndStr *>(*i);
         if (!e) {
             atStartOfLine = false;
@@ -223,9 +223,10 @@ static Expr * stripIndentation(const Pos & pos, SymbolTable & symbols, vector<Ex
         /* Remove the last line if it is empty and consists only of
            spaces. */
         if (n == 1) {
-            string::size_type p = s2.find_last_of('\n');
-            if (p != string::npos && s2.find_first_not_of(' ', p + 1) == string::npos)
-                s2 = string(s2, 0, p + 1);
+            std::string::size_type p = s2.find_last_of('\n');
+            if (p != std::string::npos && s2.find_first_not_of(' ', p + 1) == std::string::npos) {
+                s2 = std::string(s2, 0, p + 1);
+            }
         }
 
         es2->push_back(new ExprString(symbols.Create(s2)));
@@ -354,7 +355,7 @@ expr_op
   | expr_op UPDATE expr_op { $$ = new ExprOpUpdate(CUR_POS, $1, $3); }
   | expr_op '?' attrpath { $$ = new ExprOpHasAttr($1, *$3); }
   | expr_op '+' expr_op
-    { $$ = new ExprConcatStrings(CUR_POS, false, new vector<Expr *>({$1, $3})); }
+    { $$ = new ExprConcatStrings(CUR_POS, false, new std::vector<Expr *>({$1, $3})); }
   | expr_op '-' expr_op { $$ = new ExprApp(CUR_POS, new ExprApp(new ExprVar(data->symbols.Create("__sub")), $1), $3); }
   | expr_op '*' expr_op { $$ = new ExprApp(CUR_POS, new ExprApp(new ExprVar(data->symbols.Create("__mul")), $1), $3); }
   | expr_op '/' expr_op { $$ = new ExprApp(CUR_POS, new ExprApp(new ExprVar(data->symbols.Create("__div")), $1), $3); }
@@ -394,7 +395,7 @@ expr_simple
       $$ = stripIndentation(CUR_POS, data->symbols, *$2);
   }
   | PATH { $$ = new ExprPath(absPath($1, data->basePath)); }
-  | HPATH { $$ = new ExprPath(getHome() + string{$1 + 1}); }
+  | HPATH { $$ = new ExprPath(getHome() + std::string{$1 + 1}); }
   | SPATH {
       std::string path($1 + 1, strlen($1) - 2);
       $$ = new ExprApp(CUR_POS,
@@ -424,9 +425,9 @@ string_parts
 string_parts_interpolated
   : string_parts_interpolated STR { $$ = $1; $1->push_back($2); }
   | string_parts_interpolated DOLLAR_CURLY expr '}' { $$ = $1; $1->push_back($3); }
-  | DOLLAR_CURLY expr '}' { $$ = new vector<Expr *>; $$->push_back($2); }
+  | DOLLAR_CURLY expr '}' { $$ = new std::vector<Expr *>; $$->push_back($2); }
   | STR DOLLAR_CURLY expr '}' {
-      $$ = new vector<Expr *>;
+      $$ = new std::vector<Expr *>;
       $$->push_back($1);
       $$->push_back($3);
     }
@@ -435,7 +436,7 @@ string_parts_interpolated
 ind_string_parts
   : ind_string_parts IND_STR { $$ = $1; $1->push_back($2); }
   | ind_string_parts DOLLAR_CURLY expr '}' { $$ = $1; $1->push_back($3); }
-  | { $$ = new vector<Expr *>; }
+  | { $$ = new std::vector<Expr *>; }
   ;
 
 binds
@@ -487,9 +488,9 @@ attrpath
       } else
           $$->push_back(AttrName($3));
     }
-  | attr { $$ = new vector<AttrName>; $$->push_back(AttrName(data->symbols.Create($1))); }
+  | attr { $$ = new std::vector<AttrName>; $$->push_back(AttrName(data->symbols.Create($1))); }
   | string_attr
-    { $$ = new vector<AttrName>;
+    { $$ = new std::vector<AttrName>;
       ExprString *str = dynamic_cast<ExprString *>($1);
       if (str) {
           $$->push_back(AttrName(str->s));
@@ -603,7 +604,7 @@ Expr * EvalState::parseExprFromFile(const Path & path, StaticEnv & staticEnv)
 
 Expr * EvalState::parseExprFromString(const std::string & s, const Path & basePath, StaticEnv & staticEnv)
 {
-    return parse(s.c_str(), "(string)", basePath, staticEnv);
+    return parse(s.c_str(), "(std::string)", basePath, staticEnv);
 }
 
 
@@ -625,11 +626,11 @@ void EvalState::addToSearchPath(const std::string & s)
     size_t pos = s.find('=');
     std::string prefix;
     Path path;
-    if (pos == string::npos) {
+    if (pos == std::string::npos) {
         path = s;
     } else {
-        prefix = string(s, 0, pos);
-        path = string(s, pos + 1);
+        prefix = std::string(s, 0, pos);
+        path = std::string(s, pos + 1);
     }
 
     searchPath.emplace_back(prefix, path);
@@ -653,7 +654,7 @@ Path EvalState::findFile(SearchPath & searchPath, const std::string & path, cons
             if (path.compare(0, s, i.first) != 0 ||
                 (path.size() > s && path[s] != '/'))
                 continue;
-            suffix = path.size() == s ? "" : "/" + string(path, s);
+            suffix = path.size() == s ? "" : "/" + std::string(path, s);
         }
         auto r = resolveSearchPathElem(i);
         if (!r.first) { continue; }
@@ -662,7 +663,7 @@ Path EvalState::findFile(SearchPath & searchPath, const std::string & path, cons
     }
     format f = format(
         "file '%1%' was not found in the Nix search path (add it using $NIX_PATH or -I)"
-        + string(pos ? ", at %2%" : ""));
+        + std::string(pos ? ", at %2%" : ""));
     f.exceptions(boost::io::all_error_bits ^ boost::io::too_many_args_bit);
     throw ThrownError(f % path % pos);
 }
diff --git a/third_party/nix/src/libexpr/primops.cc b/third_party/nix/src/libexpr/primops.cc
index 5a9f1fe72076..fa0057041713 100644
--- a/third_party/nix/src/libexpr/primops.cc
+++ b/third_party/nix/src/libexpr/primops.cc
@@ -32,13 +32,14 @@ namespace nix {
 
 /* Decode a context string ‘!<name>!<path>’ into a pair <path,
    name>. */
-std::pair<string, string> decodeContext(const std::string& s) {
+std::pair<std::string, std::string> decodeContext(const std::string& s) {
   if (s.at(0) == '!') {
     size_t index = s.find('!', 1);
-    return std::pair<string, string>(string(s, index + 1),
-                                     string(s, 1, index - 1));
+    return std::pair<std::string, std::string>(std::string(s, index + 1),
+                                               std::string(s, 1, index - 1));
   }
-  return std::pair<string, string>(s.at(0) == '/' ? s : string(s, 1), "");
+  return std::pair<std::string, std::string>(
+      s.at(0) == '/' ? s : std::string(s, 1), "");
 }
 
 InvalidPathError::InvalidPathError(const Path& path)
@@ -48,7 +49,7 @@ void EvalState::realiseContext(const PathSet& context) {
   PathSet drvs;
 
   for (auto& i : context) {
-    std::pair<string, string> decoded = decodeContext(i);
+    std::pair<std::string, std::string> decoded = decodeContext(i);
     Path ctx = decoded.first;
     assert(store->isStorePath(ctx));
     if (!store->isValidPath(ctx)) {
@@ -382,9 +383,9 @@ struct CompareValues {
 };
 
 #if HAVE_BOEHMGC
-typedef list<Value*, gc_allocator<Value*>> ValueList;
+typedef std::list<Value*, gc_allocator<Value*>> ValueList;
 #else
-typedef list<Value*> ValueList;
+typedef std::list<Value*> ValueList;
 #endif
 
 static void prim_genericClosure(EvalState& state, const Pos& pos, Value** args,
@@ -418,7 +419,7 @@ static void prim_genericClosure(EvalState& state, const Pos& pos, Value** args,
   ValueList res;
   // `doneKeys' doesn't need to be a GC root, because its values are
   // reachable from res.
-  set<Value*, CompareValues> doneKeys;
+  std::set<Value*, CompareValues> doneKeys;
   while (!workSet.empty()) {
     Value* e = *(workSet.begin());
     workSet.pop_front();
@@ -743,7 +744,7 @@ static void prim_derivationStrict(EvalState& state, const Pos& pos,
     if (path.at(0) == '=') {
       /* !!! This doesn't work if readOnlyMode is set. */
       PathSet refs;
-      state.store->computeFSClosure(string(path, 1), refs);
+      state.store->computeFSClosure(std::string(path, 1), refs);
       for (auto& j : refs) {
         drv.inputSrcs.insert(j);
         if (isDerivation(j)) {
@@ -754,7 +755,7 @@ static void prim_derivationStrict(EvalState& state, const Pos& pos,
 
     /* Handle derivation outputs of the form ‘!<name>!<path>’. */
     else if (path.at(0) == '!') {
-      std::pair<string, string> ctx = decodeContext(path);
+      std::pair<std::string, std::string> ctx = decodeContext(path);
       drv.inputDrvs[ctx.first].insert(ctx.second);
     }
 
@@ -965,7 +966,7 @@ static void prim_readFile(EvalState& state, const Pos& pos, Value** args,
   }
   std::string s =
       readFile(state.checkSourcePath(state.toRealPath(path, context)));
-  if (s.find((char)0) != string::npos) {
+  if (s.find((char)0) != std::string::npos) {
     throw Error(format("the contents of the file '%1%' cannot be represented "
                        "as a Nix string") %
                 path);
@@ -1899,7 +1900,7 @@ static void prim_substring(EvalState& state, const Pos& pos, Value** args,
                     pos);
   }
 
-  mkString(v, (unsigned int)start >= s.size() ? "" : string(s, start, len),
+  mkString(v, (unsigned int)start >= s.size() ? "" : std::string(s, start, len),
            context);
 }
 
@@ -2066,13 +2067,13 @@ static void prim_replaceStrings(EvalState& state, const Pos& pos, Value** args,
                     pos);
   }
 
-  vector<string> from;
+  std::vector<std::string> from;
   from.reserve(args[0]->listSize());
   for (unsigned int n = 0; n < args[0]->listSize(); ++n) {
     from.push_back(state.forceString(*args[0]->listElems()[n], pos));
   }
 
-  vector<std::pair<string, PathSet>> to;
+  std::vector<std::pair<std::string, PathSet>> to;
   to.reserve(args[1]->listSize());
   for (unsigned int n = 0; n < args[1]->listSize(); ++n) {
     PathSet ctx;
diff --git a/third_party/nix/src/libexpr/primops/context.cc b/third_party/nix/src/libexpr/primops/context.cc
index 2ae8ba8aa99e..481a2910bf84 100644
--- a/third_party/nix/src/libexpr/primops/context.cc
+++ b/third_party/nix/src/libexpr/primops/context.cc
@@ -36,7 +36,7 @@ static void prim_unsafeDiscardOutputDependency(EvalState& state, const Pos& pos,
 
   PathSet context2;
   for (auto& p : context) {
-    context2.insert(p.at(0) == '=' ? string(p, 1) : p);
+    context2.insert(p.at(0) == '=' ? std::string(p, 1) : p);
   }
 
   mkString(v, s, context2);
@@ -79,10 +79,10 @@ static void prim_getContext(EvalState& state, const Pos& pos, Value** args,
     std::string output;
     const Path* path = &p;
     if (p.at(0) == '=') {
-      drv = string(p, 1);
+      drv = std::string(p, 1);
       path = &drv;
     } else if (p.at(0) == '!') {
-      std::pair<string, string> ctx = decodeContext(p);
+      std::pair<std::string, std::string> ctx = decodeContext(p);
       drv = ctx.first;
       output = ctx.second;
       path = &drv;
@@ -170,7 +170,7 @@ static void prim_appendContext(EvalState& state, const Pos& pos, Value** args,
               "derivation, to a string, at %s",
               i->name, i->pos);
         }
-        context.insert("=" + string(i->name));
+        context.insert("=" + std::string(i->name));
       }
     }
 
@@ -186,7 +186,7 @@ static void prim_appendContext(EvalState& state, const Pos& pos, Value** args,
       for (unsigned int n = 0; n < iter->second.value->listSize(); ++n) {
         auto name = state.forceStringNoCtx(*iter->second.value->listElems()[n],
                                            *iter->second.pos);
-        context.insert("!" + name + "!" + string(i->name));
+        context.insert("!" + name + "!" + std::string(i->name));
       }
     }
   }
diff --git a/third_party/nix/src/libmain/common-args.cc b/third_party/nix/src/libmain/common-args.cc
index 3d9b8ebfaefd..f85eadbf70d9 100644
--- a/third_party/nix/src/libmain/common-args.cc
+++ b/third_party/nix/src/libmain/common-args.cc
@@ -6,7 +6,7 @@
 
 namespace nix {
 
-MixCommonArgs::MixCommonArgs(const string& programName)
+MixCommonArgs::MixCommonArgs(const std::string& programName)
     : programName(programName) {
   mkFlag()
       .longName("option")
diff --git a/third_party/nix/src/libmain/common-args.hh b/third_party/nix/src/libmain/common-args.hh
index d8917b836778..88b51047dfbe 100644
--- a/third_party/nix/src/libmain/common-args.hh
+++ b/third_party/nix/src/libmain/common-args.hh
@@ -5,8 +5,8 @@
 namespace nix {
 
 struct MixCommonArgs : virtual Args {
-  string programName;
-  MixCommonArgs(const string& programName);
+  std::string programName;
+  MixCommonArgs(const std::string& programName);
 };
 
 struct MixDryRun : virtual Args {
diff --git a/third_party/nix/src/libmain/shared.cc b/third_party/nix/src/libmain/shared.cc
index d2b2a2800c46..549134872e91 100644
--- a/third_party/nix/src/libmain/shared.cc
+++ b/third_party/nix/src/libmain/shared.cc
@@ -83,8 +83,8 @@ void printMissing(const ref<Store>& store, const PathSet& willBuild,
   }
 }
 
-string getArg(const string& opt, Strings::iterator& i,
-              const Strings::iterator& end) {
+std::string getArg(const std::string& opt, Strings::iterator& i,
+                   const Strings::iterator& end) {
   ++i;
   if (i == end) {
     throw UsageError(format("'%1%' requires an argument") % opt);
@@ -246,13 +246,13 @@ void parseCmdLine(
 }
 
 void parseCmdLine(
-    const string& programName, const Strings& args,
+    const std::string& programName, const Strings& args,
     std::function<bool(Strings::iterator& arg, const Strings::iterator& end)>
         parseArg) {
   LegacyArgs(programName, std::move(parseArg)).parseCmdline(args);
 }
 
-void printVersion(const string& programName) {
+void printVersion(const std::string& programName) {
   std::cout << format("%1% (Nix) %2%") % programName % nixVersion << std::endl;
 
   // TODO(tazjin): figure out what the fuck this is
@@ -273,18 +273,18 @@ void printVersion(const string& programName) {
   throw Exit();
 }
 
-void showManPage(const string& name) {
+void showManPage(const std::string& name) {
   restoreSignals();
   setenv("MANPATH", settings.nixManDir.c_str(), 1);
   execlp("man", "man", name.c_str(), nullptr);
   throw SysError(format("command 'man %1%' failed") % name.c_str());
 }
 
-int handleExceptions(const string& programName,
+int handleExceptions(const std::string& programName,
                      const std::function<void()>& fun) {
   ReceiveInterrupts receiveInterrupts;  // FIXME: need better place for this
 
-  string error = ANSI_RED "error:" ANSI_NORMAL " ";
+  std::string error = ANSI_RED "error:" ANSI_NORMAL " ";
   try {
     try {
       fun();
@@ -328,7 +328,7 @@ RunPager::RunPager() {
   if (pager == nullptr) {
     pager = getenv("PAGER");
   }
-  if (pager && ((string)pager == "" || (string)pager == "cat")) {
+  if (pager && ((std::string)pager == "" || (std::string)pager == "cat")) {
     return;
   }
 
@@ -371,7 +371,7 @@ RunPager::~RunPager() {
   }
 }
 
-string showBytes(unsigned long long bytes) {
+std::string showBytes(unsigned long long bytes) {
   return (format("%.2f MiB") % (bytes / (1024.0 * 1024.0))).str();
 }
 
diff --git a/third_party/nix/src/libmain/shared.hh b/third_party/nix/src/libmain/shared.hh
index da1c9cc66ac3..edd0a5159a9d 100644
--- a/third_party/nix/src/libmain/shared.hh
+++ b/third_party/nix/src/libmain/shared.hh
@@ -18,7 +18,7 @@ class Exit : public std::exception {
   virtual ~Exit();
 };
 
-int handleExceptions(const string& programName,
+int handleExceptions(const std::string& programName,
                      const std::function<void()>& fun);
 
 /* Don't forget to call initPlugins() after settings are initialized! */
@@ -30,11 +30,11 @@ void parseCmdLine(
         parseArg);
 
 void parseCmdLine(
-    const string& programName, const Strings& args,
+    const std::string& programName, const Strings& args,
     std::function<bool(Strings::iterator& arg, const Strings::iterator& end)>
         parseArg);
 
-void printVersion(const string& programName);
+void printVersion(const std::string& programName);
 
 /* Ugh.  No better place to put this. */
 void printGCWarning();
@@ -47,17 +47,17 @@ void printMissing(const ref<Store>& store, const PathSet& willBuild,
                   const PathSet& willSubstitute, const PathSet& unknown,
                   unsigned long long downloadSize, unsigned long long narSize);
 
-string getArg(const string& opt, Strings::iterator& i,
-              const Strings::iterator& end);
+std::string getArg(const std::string& opt, Strings::iterator& i,
+                   const Strings::iterator& end);
 
 template <class N>
-N getIntArg(const string& opt, Strings::iterator& i,
+N getIntArg(const std::string& opt, Strings::iterator& i,
             const Strings::iterator& end, bool allowUnit) {
   ++i;
   if (i == end) {
     throw UsageError(format("'%1%' requires an argument") % opt);
   }
-  string s = *i;
+  std::string s = *i;
   N multiplier = 1;
   if (allowUnit && !s.empty()) {
     char u = std::toupper(*s.rbegin());
@@ -98,7 +98,7 @@ struct LegacyArgs : public MixCommonArgs {
 };
 
 /* Show the manual page for the specified program. */
-void showManPage(const string& name);
+void showManPage(const std::string& name);
 
 /* The constructor of this class starts a pager if stdout is a
    terminal and $PAGER is set. Stdout is redirected to the pager. */
@@ -115,7 +115,7 @@ extern volatile ::sig_atomic_t blockInt;
 
 /* GC helpers. */
 
-string showBytes(unsigned long long bytes);
+std::string showBytes(unsigned long long bytes);
 
 struct GCResults;
 
diff --git a/third_party/nix/src/libstore/binary-cache-store.cc b/third_party/nix/src/libstore/binary-cache-store.cc
index 487c12b5313e..37d1c1a440a2 100644
--- a/third_party/nix/src/libstore/binary-cache-store.cc
+++ b/third_party/nix/src/libstore/binary-cache-store.cc
@@ -289,7 +289,7 @@ void BinaryCacheStore::queryPathInfoUncached(
           }});
 }
 
-Path BinaryCacheStore::addToStore(const string& name, const Path& srcPath,
+Path BinaryCacheStore::addToStore(const std::string& name, const Path& srcPath,
                                   bool recursive, HashType hashAlgo,
                                   PathFilter& filter, RepairFlag repair) {
   // FIXME: some cut&paste from LocalStore::addToStore().
@@ -316,7 +316,8 @@ Path BinaryCacheStore::addToStore(const string& name, const Path& srcPath,
   return info.path;
 }
 
-Path BinaryCacheStore::addTextToStore(const string& name, const string& s,
+Path BinaryCacheStore::addTextToStore(const std::string& name,
+                                      const std::string& s,
                                       const PathSet& references,
                                       RepairFlag repair) {
   ValidPathInfo info;
diff --git a/third_party/nix/src/libstore/binary-cache-store.hh b/third_party/nix/src/libstore/binary-cache-store.hh
index f5bd66bbd6e1..b8e1ccabf264 100644
--- a/third_party/nix/src/libstore/binary-cache-store.hh
+++ b/third_party/nix/src/libstore/binary-cache-store.hh
@@ -74,7 +74,7 @@ class BinaryCacheStore : public Store {
       const Path& path,
       Callback<std::shared_ptr<ValidPathInfo>> callback) noexcept override;
 
-  Path queryPathFromHashPart(const string& hashPart) override {
+  Path queryPathFromHashPart(const std::string& hashPart) override {
     unsupported("queryPathFromHashPart");
   }
 
@@ -84,11 +84,11 @@ class BinaryCacheStore : public Store {
                   RepairFlag repair, CheckSigsFlag checkSigs,
                   std::shared_ptr<FSAccessor> accessor) override;
 
-  Path addToStore(const string& name, const Path& srcPath, bool recursive,
+  Path addToStore(const std::string& name, const Path& srcPath, bool recursive,
                   HashType hashAlgo, PathFilter& filter,
                   RepairFlag repair) override;
 
-  Path addTextToStore(const string& name, const string& s,
+  Path addTextToStore(const std::string& name, const std::string& s,
                       const PathSet& references, RepairFlag repair) override;
 
   void narFromPath(const Path& path, Sink& sink) override;
diff --git a/third_party/nix/src/libstore/build.cc b/third_party/nix/src/libstore/build.cc
index 266cedc096ad..49204a72a8cd 100644
--- a/third_party/nix/src/libstore/build.cc
+++ b/third_party/nix/src/libstore/build.cc
@@ -73,9 +73,7 @@
 
 namespace nix {
 
-using std::map;
-
-static string pathNullDevice = "/dev/null";
+static std::string pathNullDevice = "/dev/null";
 
 /* Forward definition. */
 class Worker;
@@ -92,11 +90,11 @@ struct CompareGoalPtrs {
 };
 
 /* Set of goals. */
-typedef set<GoalPtr, CompareGoalPtrs> Goals;
-using WeakGoals = list<WeakGoalPtr>;
+typedef std::set<GoalPtr, CompareGoalPtrs> Goals;
+using WeakGoals = std::list<WeakGoalPtr>;
 
 /* A map of paths to goals (and the other way around). */
-typedef map<Path, WeakGoalPtr> WeakGoalMap;
+typedef std::map<Path, WeakGoalPtr> WeakGoalMap;
 
 class Goal : public std::enable_shared_from_this<Goal> {
  public:
@@ -131,7 +129,7 @@ class Goal : public std::enable_shared_from_this<Goal> {
   unsigned int nrIncompleteClosure;
 
   /* Name of this goal for debugging purposes. */
-  string name;
+  std::string name;
 
   /* Whether the goal is finished. */
   ExitCode exitCode;
@@ -150,13 +148,13 @@ class Goal : public std::enable_shared_from_this<Goal> {
 
   virtual void waiteeDone(GoalPtr waitee, ExitCode result);
 
-  virtual void handleChildOutput(int fd, const string& data) { abort(); }
+  virtual void handleChildOutput(int fd, const std::string& data) { abort(); }
 
   virtual void handleEOF(int fd) { abort(); }
 
   void trace(const FormatOrString& fs);
 
-  string getName() { return name; }
+  std::string getName() { return name; }
 
   ExitCode getExitCode() { return exitCode; }
 
@@ -165,15 +163,15 @@ class Goal : public std::enable_shared_from_this<Goal> {
      by the worker (important!), etc. */
   virtual void timedOut() = 0;
 
-  virtual string key() = 0;
+  virtual std::string key() = 0;
 
  protected:
   virtual void amDone(ExitCode result);
 };
 
 bool CompareGoalPtrs::operator()(const GoalPtr& a, const GoalPtr& b) const {
-  string s1 = a->key();
-  string s2 = b->key();
+  std::string s1 = a->key();
+  std::string s2 = b->key();
   return s1 < s2;
 }
 
@@ -185,7 +183,7 @@ using steady_time_point = std::chrono::time_point<std::chrono::steady_clock>;
 struct Child {
   WeakGoalPtr goal;
   Goal* goal2;  // ugly hackery
-  set<int> fds;
+  std::set<int> fds;
   bool respectTimeouts;
   bool inBuildSlot;
   steady_time_point lastOutput; /* time we last got output on stdout/stderr */
@@ -293,8 +291,8 @@ class Worker {
 
   /* Registers a running child process.  `inBuildSlot' means that
      the process counts towards the jobs limit. */
-  void childStarted(const GoalPtr& goal, const set<int>& fds, bool inBuildSlot,
-                    bool respectTimeouts);
+  void childStarted(const GoalPtr& goal, const std::set<int>& fds,
+                    bool inBuildSlot, bool respectTimeouts);
 
   /* Unregisters a running child process.  `wakeSleepers' should be
      false if there is no sense in waking up goals that are sleeping
@@ -483,7 +481,7 @@ class UserLock {
   Path fnUserLock;
   AutoCloseFD fdUserLock;
 
-  string user;
+  std::string user;
   uid_t uid;
   gid_t gid;
   std::vector<gid_t> supplementaryGIDs;
@@ -494,7 +492,7 @@ class UserLock {
 
   void kill();
 
-  string getUser() { return user; }
+  std::string getUser() { return user; }
   uid_t getUID() {
     assert(uid);
     return uid;
@@ -710,12 +708,12 @@ HookInstance::~HookInstance() {
 
 //////////////////////////////////////////////////////////////////////
 
-typedef map<std::string, std::string> StringRewrites;
+typedef std::map<std::string, std::string> StringRewrites;
 
 std::string rewriteStrings(std::string s, const StringRewrites& rewrites) {
   for (auto& i : rewrites) {
     size_t j = 0;
-    while ((j = s.find(i.first, j)) != string::npos) {
+    while ((j = s.find(i.first, j)) != std::string::npos) {
       s.replace(j, i.first.size(), i.second);
     }
   }
@@ -831,16 +829,16 @@ class DerivationGoal : public Goal {
     explicit ChrootPath(Path source = "", bool optional = false)
         : source(std::move(source)), optional(optional) {}
   };
-  typedef map<Path, ChrootPath>
+  typedef std::map<Path, ChrootPath>
       DirsInChroot;  // maps target path to source path
   DirsInChroot dirsInChroot;
 
-  typedef map<string, string> Environment;
+  typedef std::map<std::string, std::string> Environment;
   Environment env;
 
   /* Hash rewriting. */
   StringRewrites inputRewrites, outputRewrites;
-  typedef map<Path, Path> RedirectedOutputs;
+  typedef std::map<Path, Path> RedirectedOutputs;
   RedirectedOutputs redirectedOutputs;
 
   BuildMode buildMode;
@@ -886,7 +884,7 @@ class DerivationGoal : public Goal {
 
   void timedOut() override;
 
-  string key() override {
+  std::string key() override {
     /* Ensure that derivations get built in order of their name,
        i.e. a derivation named "aardvark" always comes before
        "baboon". And substitution goals always happen before
@@ -956,7 +954,7 @@ class DerivationGoal : public Goal {
   void deleteTmpDir(bool force);
 
   /* Callback used by the worker to write to the log. */
-  void handleChildOutput(int fd, const string& data) override;
+  void handleChildOutput(int fd, const std::string& data) override;
   void handleEOF(int fd) override;
   void flushLine();
 
@@ -975,7 +973,7 @@ class DerivationGoal : public Goal {
 
   void amDone(ExitCode result) override { Goal::amDone(result); }
 
-  void done(BuildResult::Status status, const string& msg = "");
+  void done(BuildResult::Status status, const std::string& msg = "");
 
   PathSet exportReferences(const PathSet& storePaths);
 };
@@ -1036,9 +1034,7 @@ DerivationGoal::~DerivationGoal() {
   }
 }
 
-inline bool DerivationGoal::needsHashRewrite() {
-  return !useChroot;
-}
+inline bool DerivationGoal::needsHashRewrite() { return !useChroot; }
 
 void DerivationGoal::killChild() {
   if (pid != -1) {
@@ -1762,11 +1758,11 @@ HookReply DerivationGoal::tryBuildHook() {
 
     /* Read the first line of input, which should be a word indicating
        whether the hook wishes to perform the build. */
-    string reply;
+    std::string reply;
     while (true) {
-      string s = readLine(worker.hook->fromHook.readSide.get());
-      if (string(s, 0, 2) == "# ") {
-        reply = string(s, 2);
+      std::string s = readLine(worker.hook->fromHook.readSide.get());
+      if (std::string(s, 0, 2) == "# ") {
+        reply = std::string(s, 2);
         break;
       }
       s += "\n";
@@ -1816,7 +1812,7 @@ HookReply DerivationGoal::tryBuildHook() {
   /* Create the log file and pipe. */
   Path logFile = openLogFile();
 
-  set<int> fds;
+  std::set<int> fds;
   fds.insert(hook->fromHook.readSide.get());
   fds.insert(hook->builderOut.readSide.get());
   worker.childStarted(shared_from_this(), fds, false, false);
@@ -1970,14 +1966,14 @@ void DerivationGoal::startBuilder() {
        temporary build directory.  The text files have the format used
        by `nix-store --register-validity'.  However, the deriver
        fields are left empty. */
-    string s = get(drv->env, "exportReferencesGraph");
+    std::string s = get(drv->env, "exportReferencesGraph");
     auto ss = tokenizeString<Strings>(s);
     if (ss.size() % 2 != 0) {
       throw BuildError(
           format("odd number of tokens in 'exportReferencesGraph': '%1%'") % s);
     }
     for (auto i = ss.begin(); i != ss.end();) {
-      string fileName = *i++;
+      std::string fileName = *i++;
       checkStoreName(fileName); /* !!! abuse of this function */
       Path storePath = *i++;
 
@@ -2007,10 +2003,11 @@ void DerivationGoal::startBuilder() {
         i.pop_back();
       }
       size_t p = i.find('=');
-      if (p == string::npos) {
+      if (p == std::string::npos) {
         dirsInChroot[i] = ChrootPath(i, optional);
       } else {
-        dirsInChroot[string(i, 0, p)] = ChrootPath(string(i, p + 1), optional);
+        dirsInChroot[std::string(i, 0, p)] =
+            ChrootPath(std::string(i, p + 1), optional);
       }
     }
     dirsInChroot[tmpDirInSandbox] = ChrootPath(tmpDir);
@@ -2211,7 +2208,7 @@ void DerivationGoal::startBuilder() {
     auto state = stBegin;
     auto lines = runProgram(settings.preBuildHook, false, args);
     auto lastPos = std::string::size_type{0};
-    for (auto nlPos = lines.find('\n'); nlPos != string::npos;
+    for (auto nlPos = lines.find('\n'); nlPos != std::string::npos;
          nlPos = lines.find('\n', lastPos)) {
       auto line = std::string{lines, lastPos, nlPos - lastPos};
       lastPos = nlPos + 1;
@@ -2226,10 +2223,11 @@ void DerivationGoal::startBuilder() {
           state = stBegin;
         } else {
           auto p = line.find('=');
-          if (p == string::npos) {
+          if (p == std::string::npos) {
             dirsInChroot[line] = ChrootPath(line);
           } else {
-            dirsInChroot[string(line, 0, p)] = ChrootPath(string(line, p + 1));
+            dirsInChroot[std::string(line, 0, p)] =
+                ChrootPath(std::string(line, p + 1));
           }
         }
       }
@@ -2454,12 +2452,12 @@ void DerivationGoal::startBuilder() {
 
   /* Check if setting up the build environment failed. */
   while (true) {
-    string msg = readLine(builderOut.readSide.get());
-    if (string(msg, 0, 1) == "\1") {
+    std::string msg = readLine(builderOut.readSide.get());
+    if (std::string(msg, 0, 1) == "\1") {
       if (msg.size() == 1) {
         break;
       }
-      throw Error(string(msg, 1));
+      throw Error(std::string(msg, 1));
     }
     DLOG(INFO) << msg;
   }
@@ -2488,7 +2486,7 @@ void DerivationGoal::initTmpDir() {
       if (passAsFile.find(i.first) == passAsFile.end()) {
         env[i.first] = i.second;
       } else {
-        string fn = ".attr-" + std::to_string(fileNr++);
+        std::string fn = ".attr-" + std::to_string(fileNr++);
         Path p = tmpDir + "/" + fn;
         writeFile(p, rewriteStrings(i.second, inputRewrites));
         chownToBuilder(p);
@@ -3110,7 +3108,7 @@ void DerivationGoal::runChild() {
 
     if (!drv->isBuiltin()) {
       builder = drv->builder.c_str();
-      string builderBasename = baseNameOf(drv->builder);
+      std::string builderBasename = baseNameOf(drv->builder);
       args.push_back(builderBasename);
     }
 
@@ -3119,7 +3117,7 @@ void DerivationGoal::runChild() {
     }
 
     /* Indicate that we managed to set up the build environment. */
-    writeFull(STDERR_FILENO, string("\1\n"));
+    writeFull(STDERR_FILENO, std::string("\1\n"));
 
     /* Execute the program.  This should not return. */
     if (drv->isBuiltin()) {
@@ -3135,11 +3133,11 @@ void DerivationGoal::runChild() {
           builtinBuildenv(drv2);
         } else {
           throw Error(format("unsupported builtin function '%1%'") %
-                      string(drv->builder, 8));
+                      std::string(drv->builder, 8));
         }
         _exit(0);
       } catch (std::exception& e) {
-        writeFull(STDERR_FILENO, "error: " + string(e.what()) + "\n");
+        writeFull(STDERR_FILENO, "error: " + std::string(e.what()) + "\n");
         _exit(1);
       }
     }
@@ -3151,7 +3149,7 @@ void DerivationGoal::runChild() {
 
   } catch (std::exception& e) {
     writeFull(STDERR_FILENO, "\1while setting up the build environment: " +
-                                 string(e.what()) + "\n");
+                                 std::string(e.what()) + "\n");
     _exit(1);
   }
 }
@@ -3621,7 +3619,7 @@ void DerivationGoal::checkOutputs(
         }
 
         if (!badPaths.empty()) {
-          string badPathsStr;
+          std::string badPathsStr;
           for (auto& i : badPaths) {
             badPathsStr += "\n  ";
             badPathsStr += i;
@@ -3705,14 +3703,14 @@ Path DerivationGoal::openLogFile() {
     return "";
   }
 
-  string baseName = baseNameOf(drvPath);
+  std::string baseName = baseNameOf(drvPath);
 
   /* Create a log file. */
   Path dir = fmt("%s/%s/%s/", worker.store.logDir, nix::LocalStore::drvsLogDir,
-                 string(baseName, 0, 2));
+                 std::string(baseName, 0, 2));
   createDirs(dir);
 
-  Path logFileName = fmt("%s/%s%s", dir, string(baseName, 2),
+  Path logFileName = fmt("%s/%s%s", dir, std::string(baseName, 2),
                          settings.compressLog ? ".bz2" : "");
 
   fdLogFile =
@@ -3759,7 +3757,7 @@ void DerivationGoal::deleteTmpDir(bool force) {
   }
 }
 
-void DerivationGoal::handleChildOutput(int fd, const string& data) {
+void DerivationGoal::handleChildOutput(int fd, const std::string& data) {
   if ((hook && fd == hook->builderOut.readSide.get()) ||
       (!hook && fd == builderOut.readSide.get())) {
     logSize += data.size();
@@ -3839,12 +3837,13 @@ PathSet DerivationGoal::checkPathValidity(bool returnValid, bool checkHash) {
 }
 
 Path DerivationGoal::addHashRewrite(const Path& path) {
-  string h1 = string(path, worker.store.storeDir.size() + 1, 32);
-  string h2 = string(hashString(htSHA256, "rewrite:" + drvPath + ":" + path)
-                         .to_string(Base32, false),
-                     0, 32);
+  std::string h1 = std::string(path, worker.store.storeDir.size() + 1, 32);
+  std::string h2 =
+      std::string(hashString(htSHA256, "rewrite:" + drvPath + ":" + path)
+                      .to_string(Base32, false),
+                  0, 32);
   Path p = worker.store.storeDir + "/" + h2 +
-           string(path, worker.store.storeDir.size() + 33);
+           std::string(path, worker.store.storeDir.size() + 33);
   deletePath(p);
   assert(path.size() == p.size());
   inputRewrites[h1] = h2;
@@ -3853,7 +3852,7 @@ Path DerivationGoal::addHashRewrite(const Path& path) {
   return p;
 }
 
-void DerivationGoal::done(BuildResult::Status status, const string& msg) {
+void DerivationGoal::done(BuildResult::Status status, const std::string& msg) {
   result.status = status;
   result.errorMsg = msg;
   amDone(result.success() ? ecSuccess : ecFailed);
@@ -3928,7 +3927,7 @@ class SubstitutionGoal : public Goal {
 
   void timedOut() override { abort(); };
 
-  string key() override {
+  std::string key() override {
     /* "a$" ensures substitution goals happen before derivation
        goals. */
     return "a$" + storePathToName(storePath) + "$" + storePath;
@@ -3945,7 +3944,7 @@ class SubstitutionGoal : public Goal {
   void finished();
 
   /* Callback used by the worker to write to the log. */
-  void handleChildOutput(int fd, const string& data) override;
+  void handleChildOutput(int fd, const std::string& data) override;
   void handleEOF(int fd) override;
 
   Path getStorePath() { return storePath; }
@@ -4204,7 +4203,7 @@ void SubstitutionGoal::finished() {
   amDone(ecSuccess);
 }
 
-void SubstitutionGoal::handleChildOutput(int fd, const string& data) {}
+void SubstitutionGoal::handleChildOutput(int fd, const std::string& data) {}
 
 void SubstitutionGoal::handleEOF(int fd) {
   if (fd == outPipe.readSide.get()) {
@@ -4321,7 +4320,7 @@ void Worker::wakeUp(const GoalPtr& goal) {
 
 unsigned Worker::getNrLocalBuilds() { return nrLocalBuilds; }
 
-void Worker::childStarted(const GoalPtr& goal, const set<int>& fds,
+void Worker::childStarted(const GoalPtr& goal, const std::set<int>& fds,
                           bool inBuildSlot, bool respectTimeouts) {
   Child child;
   child.goal = goal;
@@ -4545,7 +4544,7 @@ void Worker::waitForInput() {
     GoalPtr goal = j->goal.lock();
     assert(goal);
 
-    set<int> fds2(j->fds);
+    std::set<int> fds2(j->fds);
     std::vector<unsigned char> buffer(4096);
     for (auto& k : fds2) {
       if (FD_ISSET(k, &fds)) {
@@ -4562,7 +4561,7 @@ void Worker::waitForInput() {
           }
         } else {
           DLOG(INFO) << goal->getName() << ": read " << rd << " bytes";
-          string data((char*)buffer.data(), rd);
+          std::string data((char*)buffer.data(), rd);
           j->lastOutput = after;
           goal->handleChildOutput(k, data);
         }
diff --git a/third_party/nix/src/libstore/builtins/buildenv.cc b/third_party/nix/src/libstore/builtins/buildenv.cc
index 77ad722fab15..d14474a93d7e 100644
--- a/third_party/nix/src/libstore/builtins/buildenv.cc
+++ b/third_party/nix/src/libstore/builtins/buildenv.cc
@@ -133,7 +133,7 @@ static void addPkg(const Path& pkgDir, int priority) {
   createLinks(pkgDir, out, priority);
 
   try {
-    for (const auto& p : tokenizeString<std::vector<string>>(
+    for (const auto& p : tokenizeString<std::vector<std::string>>(
              readFile(pkgDir + "/nix-support/propagated-user-env-packages"),
              " \n"))
       if (!done.count(p)) {
@@ -157,7 +157,7 @@ struct Package {
 typedef std::vector<Package> Packages;
 
 void builtinBuildenv(const BasicDerivation& drv) {
-  auto getAttr = [&](const string& name) {
+  auto getAttr = [&](const std::string& name) {
     auto i = drv.env.find(name);
     if (i == drv.env.end()) {
       throw Error("attribute '%s' missing", name);
diff --git a/third_party/nix/src/libstore/builtins/fetchurl.cc b/third_party/nix/src/libstore/builtins/fetchurl.cc
index c3f38a943f57..97260d2e5229 100644
--- a/third_party/nix/src/libstore/builtins/fetchurl.cc
+++ b/third_party/nix/src/libstore/builtins/fetchurl.cc
@@ -17,7 +17,7 @@ void builtinFetchurl(const BasicDerivation& drv, const std::string& netrcData) {
     writeFile(settings.netrcFile, netrcData, 0600);
   }
 
-  auto getAttr = [&](const string& name) {
+  auto getAttr = [&](const std::string& name) {
     auto i = drv.env.find(name);
     if (i == drv.env.end())
       throw Error(format("attribute '%s' missing") % name);
diff --git a/third_party/nix/src/libstore/crypto.cc b/third_party/nix/src/libstore/crypto.cc
index 90580b8dc902..eb5bb6670738 100644
--- a/third_party/nix/src/libstore/crypto.cc
+++ b/third_party/nix/src/libstore/crypto.cc
@@ -9,7 +9,7 @@
 
 namespace nix {
 
-static std::pair<std::string, std::string> split(const string& s) {
+static std::pair<std::string, std::string> split(const std::string& s) {
   size_t colon = s.find(':');
   if (colon == std::string::npos || colon == 0) {
     return {"", ""};
@@ -17,7 +17,7 @@ static std::pair<std::string, std::string> split(const string& s) {
   return {std::string(s, 0, colon), std::string(s, colon + 1)};
 }
 
-Key::Key(const string& s) {
+Key::Key(const std::string& s) {
   auto ss = split(s);
 
   name = ss.first;
@@ -30,7 +30,7 @@ Key::Key(const string& s) {
   key = base64Decode(key);
 }
 
-SecretKey::SecretKey(const string& s) : Key(s) {
+SecretKey::SecretKey(const std::string& s) : Key(s) {
 #if HAVE_SODIUM
   if (key.size() != crypto_sign_SECRETKEYBYTES) {
     throw Error("secret key is not valid");
@@ -68,7 +68,7 @@ PublicKey SecretKey::toPublicKey() const {
 #endif
 }
 
-PublicKey::PublicKey(const string& s) : Key(s) {
+PublicKey::PublicKey(const std::string& s) : Key(s) {
 #if HAVE_SODIUM
   if (key.size() != crypto_sign_PUBLICKEYBYTES) {
     throw Error("public key is not valid");
diff --git a/third_party/nix/src/libstore/derivations.cc b/third_party/nix/src/libstore/derivations.cc
index 9c71d7209e37..f8770327bf9e 100644
--- a/third_party/nix/src/libstore/derivations.cc
+++ b/third_party/nix/src/libstore/derivations.cc
@@ -11,11 +11,11 @@ namespace nix {
 
 void DerivationOutput::parseHashInfo(bool& recursive, Hash& hash) const {
   recursive = false;
-  string algo = hashAlgo;
+  std::string algo = hashAlgo;
 
-  if (string(algo, 0, 2) == "r:") {
+  if (std::string(algo, 0, 2) == "r:") {
     recursive = true;
-    algo = string(algo, 2);
+    algo = std::string(algo, 2);
   }
 
   HashType hashType = parseHashType(algo);
@@ -26,7 +26,7 @@ void DerivationOutput::parseHashInfo(bool& recursive, Hash& hash) const {
   hash = Hash(this->hash, hashType);
 }
 
-Path BasicDerivation::findOutput(const string& id) const {
+Path BasicDerivation::findOutput(const std::string& id) const {
   auto i = outputs.find(id);
   if (i == outputs.end()) {
     throw Error(format("derivation has no output '%1%'") % id);
@@ -35,11 +35,11 @@ Path BasicDerivation::findOutput(const string& id) const {
 }
 
 bool BasicDerivation::isBuiltin() const {
-  return string(builder, 0, 8) == "builtin:";
+  return std::string(builder, 0, 8) == "builtin:";
 }
 
 Path writeDerivation(const ref<Store>& store, const Derivation& drv,
-                     const string& name, RepairFlag repair) {
+                     const std::string& name, RepairFlag repair) {
   PathSet references;
   references.insert(drv.inputSrcs.begin(), drv.inputSrcs.end());
   for (auto& i : drv.inputDrvs) {
@@ -48,25 +48,25 @@ Path writeDerivation(const ref<Store>& store, const Derivation& drv,
   /* Note that the outputs of a derivation are *not* references
      (that can be missing (of course) and should not necessarily be
      held during a garbage collection). */
-  string suffix = name + drvExtension;
-  string contents = drv.unparse();
+  std::string suffix = name + drvExtension;
+  std::string contents = drv.unparse();
   return settings.readOnlyMode
              ? store->computeStorePathForText(suffix, contents, references)
              : store->addTextToStore(suffix, contents, references, repair);
 }
 
 /* Read string `s' from stream `str'. */
-static void expect(std::istream& str, const string& s) {
+static void expect(std::istream& str, const std::string& s) {
   char s2[s.size()];
   str.read(s2, s.size());
-  if (string(s2, s.size()) != s) {
+  if (std::string(s2, s.size()) != s) {
     throw FormatError(format("expected string '%1%'") % s);
   }
 }
 
 /* Read a C-style string from stream `str'. */
-static string parseString(std::istream& str) {
-  string res;
+static std::string parseString(std::istream& str) {
+  std::string res;
   expect(str, "\"");
   int c;
   while ((c = str.get()) != '"') {
@@ -89,7 +89,7 @@ static string parseString(std::istream& str) {
 }
 
 static Path parsePath(std::istream& str) {
-  string s = parseString(str);
+  std::string s = parseString(str);
   if (s.empty() || s[0] != '/') {
     throw FormatError(format("bad path '%1%' in derivation") % s);
   }
@@ -116,7 +116,7 @@ static StringSet parseStrings(std::istream& str, bool arePaths) {
   return res;
 }
 
-static Derivation parseDerivation(const string& s) {
+static Derivation parseDerivation(const std::string& s) {
   Derivation drv;
   istringstream_nocopy str(s);
   expect(str, "Derive([");
@@ -125,7 +125,7 @@ static Derivation parseDerivation(const string& s) {
   while (!endOfList(str)) {
     DerivationOutput out;
     expect(str, "(");
-    string id = parseString(str);
+    std::string id = parseString(str);
     expect(str, ",");
     out.path = parsePath(str);
     expect(str, ",");
@@ -163,9 +163,9 @@ static Derivation parseDerivation(const string& s) {
   expect(str, ",[");
   while (!endOfList(str)) {
     expect(str, "(");
-    string name = parseString(str);
+    std::string name = parseString(str);
     expect(str, ",");
-    string value = parseString(str);
+    std::string value = parseString(str);
     expect(str, ")");
     drv.env[name] = value;
   }
@@ -195,7 +195,7 @@ Derivation Store::derivationFromPath(const Path& drvPath) {
   }
 }
 
-static void printString(string& res, const string& s) {
+static void printString(std::string& res, const std::string& s) {
   res += '"';
   for (const char* i = s.c_str(); *i != 0; i++) {
     if (*i == '\"' || *i == '\\') {
@@ -215,7 +215,8 @@ static void printString(string& res, const string& s) {
 }
 
 template <class ForwardIterator>
-static void printStrings(string& res, ForwardIterator i, ForwardIterator j) {
+static void printStrings(std::string& res, ForwardIterator i,
+                         ForwardIterator j) {
   res += '[';
   bool first = true;
   for (; i != j; ++i) {
@@ -229,8 +230,8 @@ static void printStrings(string& res, ForwardIterator i, ForwardIterator j) {
   res += ']';
 }
 
-string Derivation::unparse() const {
-  string s;
+std::string Derivation::unparse() const {
+  std::string s;
   s.reserve(65536);
   s += "Derive([";
 
@@ -297,7 +298,7 @@ string Derivation::unparse() const {
   return s;
 }
 
-bool isDerivation(const string& fileName) {
+bool isDerivation(const std::string& fileName) {
   return hasSuffix(fileName, drvExtension);
 }
 
@@ -354,22 +355,23 @@ Hash hashDerivationModulo(Store& store, Derivation drv) {
   return hashString(htSHA256, drv.unparse());
 }
 
-DrvPathWithOutputs parseDrvPathWithOutputs(const string& s) {
+DrvPathWithOutputs parseDrvPathWithOutputs(const std::string& s) {
   size_t n = s.find('!');
   return n == std::string::npos
-             ? DrvPathWithOutputs(s, std::set<string>())
-             : DrvPathWithOutputs(
-                   string(s, 0, n),
-                   tokenizeString<std::set<string> >(string(s, n + 1), ","));
+             ? DrvPathWithOutputs(s, std::set<std::string>())
+             : DrvPathWithOutputs(std::string(s, 0, n),
+                                  tokenizeString<std::set<std::string> >(
+                                      std::string(s, n + 1), ","));
 }
 
 Path makeDrvPathWithOutputs(const Path& drvPath,
-                            const std::set<string>& outputs) {
+                            const std::set<std::string>& outputs) {
   return outputs.empty() ? drvPath
                          : drvPath + "!" + concatStringsSep(",", outputs);
 }
 
-bool wantOutput(const string& output, const std::set<string>& wanted) {
+bool wantOutput(const std::string& output,
+                const std::set<std::string>& wanted) {
   return wanted.empty() || wanted.find(output) != wanted.end();
 }
 
diff --git a/third_party/nix/src/libstore/derivations.hh b/third_party/nix/src/libstore/derivations.hh
index 52b951f5e9d9..ae365e68bf3a 100644
--- a/third_party/nix/src/libstore/derivations.hh
+++ b/third_party/nix/src/libstore/derivations.hh
@@ -9,16 +9,16 @@
 namespace nix {
 
 /* Extension of derivations in the Nix store. */
-const string drvExtension = ".drv";
+const std::string drvExtension = ".drv";
 
 /* Abstract syntax of derivations. */
 
 struct DerivationOutput {
   Path path;
-  string hashAlgo; /* hash used for expected hash computation */
-  string hash;     /* expected hash, may be null */
+  std::string hashAlgo; /* hash used for expected hash computation */
+  std::string hash;     /* expected hash, may be null */
   DerivationOutput() {}
-  DerivationOutput(Path path, string hashAlgo, string hash) {
+  DerivationOutput(Path path, std::string hashAlgo, std::string hash) {
     this->path = path;
     this->hashAlgo = hashAlgo;
     this->hash = hash;
@@ -26,18 +26,18 @@ struct DerivationOutput {
   void parseHashInfo(bool& recursive, Hash& hash) const;
 };
 
-typedef std::map<string, DerivationOutput> DerivationOutputs;
+typedef std::map<std::string, DerivationOutput> DerivationOutputs;
 
 /* For inputs that are sub-derivations, we specify exactly which
    output IDs we are interested in. */
 typedef std::map<Path, StringSet> DerivationInputs;
 
-typedef std::map<string, string> StringPairs;
+typedef std::map<std::string, std::string> StringPairs;
 
 struct BasicDerivation {
   DerivationOutputs outputs; /* keyed on symbolic IDs */
   PathSet inputSrcs;         /* inputs that are sources */
-  string platform;
+  std::string platform;
   Path builder;
   Strings args;
   StringPairs env;
@@ -46,7 +46,7 @@ struct BasicDerivation {
 
   /* Return the path corresponding to the output identifier `id' in
      the given derivation. */
-  Path findOutput(const string& id) const;
+  Path findOutput(const std::string& id) const;
 
   bool isBuiltin() const;
 
@@ -68,14 +68,14 @@ class Store;
 
 /* Write a derivation to the Nix store, and return its path. */
 Path writeDerivation(const ref<Store>& store, const Derivation& drv,
-                     const string& name, RepairFlag repair = NoRepair);
+                     const std::string& name, RepairFlag repair = NoRepair);
 
 /* Read a derivation from a file. */
 Derivation readDerivation(const Path& drvPath);
 
 /* Check whether a file name ends with the extension for
    derivations. */
-bool isDerivation(const string& fileName);
+bool isDerivation(const std::string& fileName);
 
 Hash hashDerivationModulo(Store& store, Derivation drv);
 
@@ -87,13 +87,13 @@ extern DrvHashes drvHashes;  // FIXME: global, not thread-safe
 /* Split a string specifying a derivation and a set of outputs
    (/nix/store/hash-foo!out1,out2,...) into the derivation path and
    the outputs. */
-typedef std::pair<string, std::set<string> > DrvPathWithOutputs;
-DrvPathWithOutputs parseDrvPathWithOutputs(const string& s);
+typedef std::pair<std::string, std::set<std::string> > DrvPathWithOutputs;
+DrvPathWithOutputs parseDrvPathWithOutputs(const std::string& s);
 
 Path makeDrvPathWithOutputs(const Path& drvPath,
-                            const std::set<string>& outputs);
+                            const std::set<std::string>& outputs);
 
-bool wantOutput(const string& output, const std::set<string>& wanted);
+bool wantOutput(const std::string& output, const std::set<std::string>& wanted);
 
 struct Source;
 struct Sink;
diff --git a/third_party/nix/src/libstore/download.cc b/third_party/nix/src/libstore/download.cc
index 876734478785..c96caf474c0d 100644
--- a/third_party/nix/src/libstore/download.cc
+++ b/third_party/nix/src/libstore/download.cc
@@ -177,7 +177,7 @@ struct CurlDownloader : public Downloader {
       DLOG(INFO) << "got header for '" << request.uri << "': " << trim(line);
       if (line.compare(0, 5, "HTTP/") == 0) {  // new response starts
         result.etag = "";
-        auto ss = tokenizeString<vector<string>>(line, " ");
+        auto ss = tokenizeString<std::vector<std::string>>(line, " ");
         status = ss.size() >= 2 ? ss[1] : "";
         result.data = std::make_shared<std::string>();
         result.bodySize = 0;
@@ -185,10 +185,10 @@ struct CurlDownloader : public Downloader {
         encoding = "";
       } else {
         auto i = line.find(':');
-        if (i != string::npos) {
-          string name = toLower(trim(string(line, 0, i)));
+        if (i != std::string::npos) {
+          std::string name = toLower(trim(std::string(line, 0, i)));
           if (name == "etag") {
-            result.etag = trim(string(line, i + 1));
+            result.etag = trim(std::string(line, i + 1));
             /* Hack to work around a GitHub bug: it sends
                ETags, but ignores If-None-Match. So if we get
                the expected ETag on a 200 response, then shut
@@ -200,7 +200,7 @@ struct CurlDownloader : public Downloader {
               return 0;
             }
           } else if (name == "content-encoding") {
-            encoding = trim(string(line, i + 1));
+            encoding = trim(std::string(line, i + 1));
           } else if (name == "accept-ranges" &&
                      toLower(trim(std::string(line, i + 1))) == "bytes") {
             acceptRanges = true;
@@ -868,8 +868,8 @@ CachedDownloadResult Downloader::downloadCached(
   auto name = request.name;
   if (name.empty()) {
     auto p = url.rfind('/');
-    if (p != string::npos) {
-      name = string(url, p + 1);
+    if (p != std::string::npos) {
+      name = std::string(url, p + 1);
     }
   }
 
@@ -888,8 +888,8 @@ CachedDownloadResult Downloader::downloadCached(
   Path cacheDir = getCacheDir() + "/nix/tarballs";
   createDirs(cacheDir);
 
-  string urlHash = hashString(htSHA256, name + std::string("\0"s) + url)
-                       .to_string(Base32, false);
+  std::string urlHash = hashString(htSHA256, name + std::string("\0"s) + url)
+                            .to_string(Base32, false);
 
   Path dataFile = cacheDir + "/" + urlHash + ".info";
   Path fileLink = cacheDir + "/" + urlHash + "-file";
@@ -898,7 +898,7 @@ CachedDownloadResult Downloader::downloadCached(
 
   Path storePath;
 
-  string expectedETag;
+  std::string expectedETag;
 
   bool skip = false;
 
@@ -908,7 +908,8 @@ CachedDownloadResult Downloader::downloadCached(
     storePath = readLink(fileLink);
     store->addTempRoot(storePath);
     if (store->isValidPath(storePath)) {
-      auto ss = tokenizeString<vector<string>>(readFile(dataFile), "\n");
+      auto ss =
+          tokenizeString<std::vector<std::string>>(readFile(dataFile), "\n");
       if (ss.size() >= 3 && ss[0] == url) {
         time_t lastChecked;
         if (string2Int(ss[2], lastChecked) &&
@@ -1009,15 +1010,15 @@ CachedDownloadResult Downloader::downloadCached(
   return result;
 }
 
-bool isUri(const string& s) {
+bool isUri(const std::string& s) {
   if (s.compare(0, 8, "channel:") == 0) {
     return true;
   }
   size_t pos = s.find("://");
-  if (pos == string::npos) {
+  if (pos == std::string::npos) {
     return false;
   }
-  string scheme(s, 0, pos);
+  std::string scheme(s, 0, pos);
   return scheme == "http" || scheme == "https" || scheme == "file" ||
          scheme == "channel" || scheme == "git" || scheme == "s3" ||
          scheme == "ssh";
diff --git a/third_party/nix/src/libstore/download.hh b/third_party/nix/src/libstore/download.hh
index 9ddbdfc15955..a988ec682669 100644
--- a/third_party/nix/src/libstore/download.hh
+++ b/third_party/nix/src/libstore/download.hh
@@ -128,6 +128,6 @@ class DownloadError : public Error {
       : Error(fs), error(error) {}
 };
 
-bool isUri(const string& s);
+bool isUri(const std::string& s);
 
 }  // namespace nix
diff --git a/third_party/nix/src/libstore/gc.cc b/third_party/nix/src/libstore/gc.cc
index bc3393265e48..1b2364c25383 100644
--- a/third_party/nix/src/libstore/gc.cc
+++ b/third_party/nix/src/libstore/gc.cc
@@ -20,8 +20,8 @@
 
 namespace nix {
 
-static string gcLockName = "gc.lock";
-static string gcRootsDir = "gcroots";
+static std::string gcLockName = "gc.lock";
+static std::string gcRootsDir = "gcroots";
 
 /* Acquire the global GC lock.  This is used to prevent new Nix
    processes from starting after the temporary root files have been
@@ -69,7 +69,7 @@ static void makeSymlink(const Path& link, const Path& target) {
 void LocalStore::syncWithGC() { AutoCloseFD fdGCLock = openGCLock(ltRead); }
 
 void LocalStore::addIndirectRoot(const Path& path) {
-  string hash = hashString(htSHA1, path).to_string(Base32, false);
+  std::string hash = hashString(htSHA1, path).to_string(Base32, false);
   Path realRoot = canonPath(
       (format("%1%/%2%/auto/%3%") % stateDir % gcRootsDir % hash).str());
   makeSymlink(realRoot, path);
@@ -105,7 +105,7 @@ Path LocalFSStore::addPermRoot(const Path& _storePath, const Path& _gcRoot,
       Path rootsDir =
           canonPath((format("%1%/%2%") % stateDir % gcRootsDir).str());
 
-      if (string(gcRoot, 0, rootsDir.size() + 1) != rootsDir + "/") {
+      if (std::string(gcRoot, 0, rootsDir.size() + 1) != rootsDir + "/") {
         throw Error(format("path '%1%' is not a valid garbage collector root; "
                            "it's not in the directory '%2%'") %
                     gcRoot % rootsDir);
@@ -184,7 +184,7 @@ void LocalStore::addTempRoot(const Path& path) {
   DLOG(INFO) << "acquiring write lock on " << fnTempRoots;
   lockFile(state->fdTempRoots.get(), ltWrite, true);
 
-  string s = path + '\0';
+  std::string s = path + '\0';
   writeFull(state->fdTempRoots.get(), s);
 
   /* Downgrade to a read lock. */
@@ -233,13 +233,13 @@ void LocalStore::findTempRoots(FDs& fds, Roots& tempRoots, bool censor) {
     lockFile(fd->get(), ltRead, true);
 
     /* Read the entire file. */
-    string contents = readFile(fd->get());
+    std::string contents = readFile(fd->get());
 
     /* Extract the roots. */
-    string::size_type pos = 0;
-    string::size_type end;
+    std::string::size_type pos = 0;
+    std::string::size_type end;
 
-    while ((end = contents.find((char)0, pos)) != string::npos) {
+    while ((end = contents.find((char)0, pos)) != std::string::npos) {
       Path root(contents, pos, end - pos);
       DLOG(INFO) << "got temporary root " << root;
       assertStorePath(root);
@@ -341,7 +341,7 @@ Roots LocalStore::findRoots(bool censor) {
   return roots;
 }
 
-static void readProcLink(const string& file, Roots& roots) {
+static void readProcLink(const std::string& file, Roots& roots) {
   /* 64 is the starting buffer size gnu readlink uses... */
   auto bufsiz = ssize_t{64};
 try_again:
@@ -365,7 +365,7 @@ try_again:
   }
 }
 
-static string quoteRegexChars(const string& raw) {
+static std::string quoteRegexChars(const std::string& raw) {
   static auto specialRegex = std::regex(R"([.^$\\*+?()\[\]{}|])");
   return std::regex_replace(raw, specialRegex, R"(\$&)");
 }
@@ -421,7 +421,7 @@ void LocalStore::findRuntimeRoots(Roots& roots, bool censor) {
 
         try {
           auto mapFile = fmt("/proc/%s/maps", ent->d_name);
-          auto mapLines = tokenizeString<std::vector<string>>(
+          auto mapLines = tokenizeString<std::vector<std::string>>(
               readFile(mapFile, true), "\n");
           for (const auto& line : mapLines) {
             auto match = std::smatch{};
@@ -458,7 +458,7 @@ void LocalStore::findRuntimeRoots(Roots& roots, bool censor) {
   if (getEnv("_NIX_TEST_NO_LSOF") == "") {
     try {
       std::regex lsofRegex(R"(^n(/.*)$)");
-      auto lsofLines = tokenizeString<std::vector<string>>(
+      auto lsofLines = tokenizeString<std::vector<std::string>>(
           runProgram(LSOF, true, {"-n", "-w", "-F", "n"}), "\n");
       for (const auto& line : lsofLines) {
         std::smatch match;
@@ -511,10 +511,10 @@ struct LocalStore::GCState {
 };
 
 bool LocalStore::isActiveTempFile(const GCState& state, const Path& path,
-                                  const string& suffix) {
+                                  const std::string& suffix) {
   return hasSuffix(path, suffix) &&
-         state.tempRoots.find(string(path, 0, path.size() - suffix.size())) !=
-             state.tempRoots.end();
+         state.tempRoots.find(std::string(
+             path, 0, path.size() - suffix.size())) != state.tempRoots.end();
 }
 
 void LocalStore::deleteGarbage(GCState& state, const Path& path) {
@@ -720,7 +720,7 @@ void LocalStore::removeUnusedLinks(const GCState& state) {
   struct dirent* dirent;
   while (errno = 0, dirent = readdir(dir.get())) {
     checkInterrupt();
-    string name = dirent->d_name;
+    std::string name = dirent->d_name;
     if (name == "." || name == "..") {
       continue;
     }
@@ -863,7 +863,7 @@ void LocalStore::collectGarbage(const GCOptions& options, GCResults& results) {
       struct dirent* dirent;
       while (errno = 0, dirent = readdir(dir.get())) {
         checkInterrupt();
-        string name = dirent->d_name;
+        std::string name = dirent->d_name;
         if (name == "." || name == "..") {
           continue;
         }
@@ -882,7 +882,7 @@ void LocalStore::collectGarbage(const GCOptions& options, GCResults& results) {
          less biased towards deleting paths that come
          alphabetically first (e.g. /nix/store/000...).  This
          matters when using --max-freed etc. */
-      vector<Path> entries_(entries.begin(), entries.end());
+      std::vector<Path> entries_(entries.begin(), entries.end());
       std::mt19937 gen(1);
       std::shuffle(entries_.begin(), entries_.end(), gen);
 
diff --git a/third_party/nix/src/libstore/globals.cc b/third_party/nix/src/libstore/globals.cc
index 856b858368ef..61293dffed50 100644
--- a/third_party/nix/src/libstore/globals.cc
+++ b/third_party/nix/src/libstore/globals.cc
@@ -105,7 +105,7 @@ StringSet Settings::getDefaultSystemFeatures() {
   return features;
 }
 
-const string nixVersion = PACKAGE_VERSION;
+const std::string nixVersion = PACKAGE_VERSION;
 
 template <>
 void BaseSetting<SandboxMode>::set(const std::string& str) {
diff --git a/third_party/nix/src/libstore/globals.hh b/third_party/nix/src/libstore/globals.hh
index 71bc2b1e7407..feff54879070 100644
--- a/third_party/nix/src/libstore/globals.hh
+++ b/third_party/nix/src/libstore/globals.hh
@@ -468,6 +468,6 @@ void initPlugins();
 
 void loadConfFile();
 
-extern const string nixVersion;
+extern const std::string nixVersion;
 
 }  // namespace nix
diff --git a/third_party/nix/src/libstore/http-binary-cache-store.cc b/third_party/nix/src/libstore/http-binary-cache-store.cc
index 1a46423b3542..c75d5f2860a7 100644
--- a/third_party/nix/src/libstore/http-binary-cache-store.cc
+++ b/third_party/nix/src/libstore/http-binary-cache-store.cc
@@ -94,7 +94,7 @@ class HttpBinaryCacheStore : public BinaryCacheStore {
   void upsertFile(const std::string& path, const std::string& data,
                   const std::string& mimeType) override {
     auto req = DownloadRequest(cacheUri + "/" + path);
-    req.data = std::make_shared<string>(data);  // FIXME: inefficient
+    req.data = std::make_shared<std::string>(data);  // FIXME: inefficient
     req.mimeType = mimeType;
     try {
       getDownloader()->download(req);
diff --git a/third_party/nix/src/libstore/legacy-ssh-store.cc b/third_party/nix/src/libstore/legacy-ssh-store.cc
index 9a84e0295657..9e6870f0da6b 100644
--- a/third_party/nix/src/libstore/legacy-ssh-store.cc
+++ b/third_party/nix/src/libstore/legacy-ssh-store.cc
@@ -43,7 +43,7 @@ struct LegacySSHStore : public Store {
 
   SSHMaster master;
 
-  LegacySSHStore(const string& host, const Params& params)
+  LegacySSHStore(const std::string& host, const Params& params)
       : Store(params),
         host(host),
         connections(make_ref<Pool<Connection>>(
@@ -85,7 +85,7 @@ struct LegacySSHStore : public Store {
     return conn;
   };
 
-  string getUri() override { return uriScheme + host; }
+  std::string getUri() override { return uriScheme + host; }
 
   void queryPathInfoUncached(
       const Path& path,
@@ -176,17 +176,17 @@ struct LegacySSHStore : public Store {
     copyNAR(conn->from, sink);
   }
 
-  Path queryPathFromHashPart(const string& hashPart) override {
+  Path queryPathFromHashPart(const std::string& hashPart) override {
     unsupported("queryPathFromHashPart");
   }
 
-  Path addToStore(const string& name, const Path& srcPath, bool recursive,
+  Path addToStore(const std::string& name, const Path& srcPath, bool recursive,
                   HashType hashAlgo, PathFilter& filter,
                   RepairFlag repair) override {
     unsupported("addToStore");
   }
 
-  Path addTextToStore(const string& name, const string& s,
+  Path addTextToStore(const std::string& name, const std::string& s,
                       const PathSet& references, RepairFlag repair) override {
     unsupported("addTextToStore");
   }
diff --git a/third_party/nix/src/libstore/local-fs-store.cc b/third_party/nix/src/libstore/local-fs-store.cc
index 2120afc0ce7c..f11c84b182a6 100644
--- a/third_party/nix/src/libstore/local-fs-store.cc
+++ b/third_party/nix/src/libstore/local-fs-store.cc
@@ -79,7 +79,7 @@ void LocalFSStore::narFromPath(const Path& path, Sink& sink) {
   dumpPath(getRealStoreDir() + std::string(path, storeDir.size()), sink);
 }
 
-const string LocalFSStore::drvsLogDir = "drvs";
+const std::string LocalFSStore::drvsLogDir = "drvs";
 
 std::shared_ptr<std::string> LocalFSStore::getBuildLog(const Path& path_) {
   auto path(path_);
@@ -97,12 +97,13 @@ std::shared_ptr<std::string> LocalFSStore::getBuildLog(const Path& path_) {
     }
   }
 
-  string baseName = baseNameOf(path);
+  std::string baseName = baseNameOf(path);
 
   for (int j = 0; j < 2; j++) {
-    Path logPath = j == 0 ? fmt("%s/%s/%s/%s", logDir, drvsLogDir,
-                                string(baseName, 0, 2), string(baseName, 2))
-                          : fmt("%s/%s/%s", logDir, drvsLogDir, baseName);
+    Path logPath =
+        j == 0 ? fmt("%s/%s/%s/%s", logDir, drvsLogDir,
+                     std::string(baseName, 0, 2), std::string(baseName, 2))
+               : fmt("%s/%s/%s", logDir, drvsLogDir, baseName);
     Path logBz2Path = logPath + ".bz2";
 
     if (pathExists(logPath)) {
diff --git a/third_party/nix/src/libstore/local-store.cc b/third_party/nix/src/libstore/local-store.cc
index a89c6a79757d..84055740de2c 100644
--- a/third_party/nix/src/libstore/local-store.cc
+++ b/third_party/nix/src/libstore/local-store.cc
@@ -10,10 +10,16 @@
 #include <fcntl.h>
 #include <glog/logging.h>
 #include <grp.h>
+#include <sched.h>
+#include <sqlite3.h>
+#include <sys/ioctl.h>
+#include <sys/mount.h>
 #include <sys/select.h>
 #include <sys/stat.h>
+#include <sys/statvfs.h>
 #include <sys/time.h>
 #include <sys/types.h>
+#include <sys/xattr.h>
 #include <unistd.h>
 #include <utime.h>
 
@@ -24,13 +30,6 @@
 #include "pathlocks.hh"
 #include "worker-protocol.hh"
 
-#include <sched.h>
-#include <sys/ioctl.h>
-#include <sys/mount.h>
-#include <sys/statvfs.h>
-#include <sys/xattr.h>
-#include <sqlite3.h>
-
 namespace nix {
 
 LocalStore::LocalStore(const Params& params)
@@ -136,7 +135,7 @@ LocalStore::LocalStore(const Params& params)
       res = posix_fallocate(fd.get(), 0, settings.reservedSize);
 #endif
       if (res == -1) {
-        writeFull(fd.get(), string(settings.reservedSize, 'X'));
+        writeFull(fd.get(), std::string(settings.reservedSize, 'X'));
         [[gnu::unused]] auto res2 = ftruncate(fd.get(), settings.reservedSize);
       }
     }
@@ -295,7 +294,7 @@ std::string LocalStore::getUri() { return "local"; }
 int LocalStore::getSchema() {
   int curSchema = 0;
   if (pathExists(schemaPath)) {
-    string s = readFile(schemaPath);
+    std::string s = readFile(schemaPath);
     if (!string2Int(s, curSchema)) {
       throw Error(format("'%1%' is corrupt") % schemaPath);
     }
@@ -310,7 +309,7 @@ void LocalStore::openDB(State& state, bool create) {
   }
 
   /* Open the Nix database. */
-  string dbPath = dbDir + "/db.sqlite";
+  std::string dbPath = dbDir + "/db.sqlite";
   auto& db(state.db);
   if (sqlite3_open_v2(dbPath.c_str(), &db.db,
                       SQLITE_OPEN_READWRITE | (create ? SQLITE_OPEN_CREATE : 0),
@@ -341,20 +340,20 @@ void LocalStore::openDB(State& state, bool create) {
      should be safe enough.  If the user asks for it, don't sync at
      all.  This can cause database corruption if the system
      crashes. */
-  string syncMode = settings.fsyncMetadata ? "normal" : "off";
+  std::string syncMode = settings.fsyncMetadata ? "normal" : "off";
   db.exec("pragma synchronous = " + syncMode);
 
   /* Set the SQLite journal mode.  WAL mode is fastest, so it's the
      default. */
-  string mode = settings.useSQLiteWAL ? "wal" : "truncate";
-  string prevMode;
+  std::string mode = settings.useSQLiteWAL ? "wal" : "truncate";
+  std::string prevMode;
   {
     SQLiteStmt stmt;
     stmt.create(db, "pragma main.journal_mode;");
     if (sqlite3_step(stmt) != SQLITE_ROW) {
       throwSQLiteError(db, "querying journal mode");
     }
-    prevMode = string((const char*)sqlite3_column_text(stmt, 0));
+    prevMode = std::string((const char*)sqlite3_column_text(stmt, 0));
   }
   if (prevMode != mode &&
       sqlite3_exec(db, ("pragma main.journal_mode = " + mode + ";").c_str(),
@@ -563,9 +562,9 @@ void canonicalisePathMetaData(const Path& path, uid_t fromUid) {
 
 void LocalStore::checkDerivationOutputs(const Path& drvPath,
                                         const Derivation& drv) {
-  string drvName = storePathToName(drvPath);
+  std::string drvName = storePathToName(drvPath);
   assert(isDerivation(drvName));
-  drvName = string(drvName, 0, drvName.size() - drvExtension.size());
+  drvName = std::string(drvName, 0, drvName.size() - drvExtension.size());
 
   if (drv.isFixedOutput()) {
     auto out = drv.outputs.find("out");
@@ -843,7 +842,7 @@ StringSet LocalStore::queryDerivationOutputNames(const Path& path) {
   });
 }
 
-Path LocalStore::queryPathFromHashPart(const string& hashPart) {
+Path LocalStore::queryPathFromHashPart(const std::string& hashPart) {
   if (hashPart.size() != storePathHashLen) {
     throw Error("invalid hash part");
   }
@@ -1096,9 +1095,9 @@ void LocalStore::addToStore(const ValidPathInfo& info, Source& source,
   }
 }
 
-Path LocalStore::addToStoreFromDump(const string& dump, const string& name,
-                                    bool recursive, HashType hashAlgo,
-                                    RepairFlag repair) {
+Path LocalStore::addToStoreFromDump(const std::string& dump,
+                                    const std::string& name, bool recursive,
+                                    HashType hashAlgo, RepairFlag repair) {
   Hash h = hashString(hashAlgo, dump);
 
   Path dstPath = makeFixedOutputPath(recursive, h, name);
@@ -1155,7 +1154,7 @@ Path LocalStore::addToStoreFromDump(const string& dump, const string& name,
   return dstPath;
 }
 
-Path LocalStore::addToStore(const string& name, const Path& _srcPath,
+Path LocalStore::addToStore(const std::string& name, const Path& _srcPath,
                             bool recursive, HashType hashAlgo,
                             PathFilter& filter, RepairFlag repair) {
   Path srcPath(absPath(_srcPath));
@@ -1173,7 +1172,7 @@ Path LocalStore::addToStore(const string& name, const Path& _srcPath,
   return addToStoreFromDump(*sink.s, name, recursive, hashAlgo, repair);
 }
 
-Path LocalStore::addTextToStore(const string& name, const string& s,
+Path LocalStore::addTextToStore(const std::string& name, const std::string& s,
                                 const PathSet& references, RepairFlag repair) {
   auto hash = hashString(htSHA256, s);
   auto dstPath = makeTextPath(name, hash, references);
diff --git a/third_party/nix/src/libstore/local-store.hh b/third_party/nix/src/libstore/local-store.hh
index 1a58df81613b..c1bfc0876412 100644
--- a/third_party/nix/src/libstore/local-store.hh
+++ b/third_party/nix/src/libstore/local-store.hh
@@ -125,7 +125,7 @@ class LocalStore : public LocalFSStore {
 
   StringSet queryDerivationOutputNames(const Path& path) override;
 
-  Path queryPathFromHashPart(const string& hashPart) override;
+  Path queryPathFromHashPart(const std::string& hashPart) override;
 
   PathSet querySubstitutablePaths(const PathSet& paths) override;
 
@@ -136,7 +136,7 @@ class LocalStore : public LocalFSStore {
                   CheckSigsFlag checkSigs,
                   std::shared_ptr<FSAccessor> accessor) override;
 
-  Path addToStore(const string& name, const Path& srcPath, bool recursive,
+  Path addToStore(const std::string& name, const Path& srcPath, bool recursive,
                   HashType hashAlgo, PathFilter& filter,
                   RepairFlag repair) override;
 
@@ -144,11 +144,11 @@ class LocalStore : public LocalFSStore {
      in `dump', which is either a NAR serialisation (if recursive ==
      true) or simply the contents of a regular file (if recursive ==
      false). */
-  Path addToStoreFromDump(const string& dump, const string& name,
+  Path addToStoreFromDump(const std::string& dump, const std::string& name,
                           bool recursive = true, HashType hashAlgo = htSHA256,
                           RepairFlag repair = NoRepair);
 
-  Path addTextToStore(const string& name, const string& s,
+  Path addTextToStore(const std::string& name, const std::string& s,
                       const PathSet& references, RepairFlag repair) override;
 
   void buildPaths(const PathSet& paths, BuildMode buildMode) override;
@@ -166,7 +166,7 @@ class LocalStore : public LocalFSStore {
 
  private:
   typedef std::shared_ptr<AutoCloseFD> FDPtr;
-  typedef list<FDPtr> FDs;
+  typedef std::list<FDPtr> FDs;
 
   void findTempRoots(FDs& fds, Roots& roots, bool censor);
 
@@ -248,7 +248,7 @@ class LocalStore : public LocalFSStore {
   void deletePathRecursive(GCState& state, const Path& path);
 
   static bool isActiveTempFile(const GCState& state, const Path& path,
-                               const string& suffix);
+                               const std::string& suffix);
 
   AutoCloseFD openGCLock(LockType lockType);
 
@@ -290,7 +290,7 @@ class LocalStore : public LocalFSStore {
 };
 
 typedef std::pair<dev_t, ino_t> Inode;
-typedef set<Inode> InodesSeen;
+typedef std::set<Inode> InodesSeen;
 
 /* "Fix", or canonicalise, the meta-data of the files in a store path
    after it has been built.  In particular:
diff --git a/third_party/nix/src/libstore/machines.cc b/third_party/nix/src/libstore/machines.cc
index 5b0c7e72ddba..2f1a7289bd84 100644
--- a/third_party/nix/src/libstore/machines.cc
+++ b/third_party/nix/src/libstore/machines.cc
@@ -32,22 +32,22 @@ Machine::Machine(decltype(storeUri)& storeUri,
       mandatoryFeatures(mandatoryFeatures),
       sshPublicHostKey(sshPublicHostKey) {}
 
-bool Machine::allSupported(const std::set<string>& features) const {
+bool Machine::allSupported(const std::set<std::string>& features) const {
   return std::all_of(features.begin(), features.end(),
-                     [&](const string& feature) {
+                     [&](const std::string& feature) {
                        return (supportedFeatures.count(feature) != 0u) ||
                               (mandatoryFeatures.count(feature) != 0u);
                      });
 }
 
-bool Machine::mandatoryMet(const std::set<string>& features) const {
+bool Machine::mandatoryMet(const std::set<std::string>& features) const {
   return std::all_of(
       mandatoryFeatures.begin(), mandatoryFeatures.end(),
-      [&](const string& feature) { return features.count(feature); });
+      [&](const std::string& feature) { return features.count(feature); });
 }
 
 void parseMachines(const std::string& s, Machines& machines) {
-  for (auto line : tokenizeString<std::vector<string>>(s, "\n;")) {
+  for (auto line : tokenizeString<std::vector<std::string>>(s, "\n;")) {
     trim(line);
     line.erase(std::find(line.begin(), line.end(), '#'), line.end());
     if (line.empty()) {
@@ -67,7 +67,7 @@ void parseMachines(const std::string& s, Machines& machines) {
       continue;
     }
 
-    auto tokens = tokenizeString<std::vector<string>>(line);
+    auto tokens = tokenizeString<std::vector<std::string>>(line);
     auto sz = tokens.size();
     if (sz < 1) {
       throw FormatError("bad machine specification '%s'", line);
@@ -79,14 +79,14 @@ void parseMachines(const std::string& s, Machines& machines) {
 
     machines.emplace_back(
         tokens[0],
-        isSet(1) ? tokenizeString<std::vector<string>>(tokens[1], ",")
-                 : std::vector<string>{settings.thisSystem},
+        isSet(1) ? tokenizeString<std::vector<std::string>>(tokens[1], ",")
+                 : std::vector<std::string>{settings.thisSystem},
         isSet(2) ? tokens[2] : "", isSet(3) ? std::stoull(tokens[3]) : 1LL,
         isSet(4) ? std::stoull(tokens[4]) : 1LL,
-        isSet(5) ? tokenizeString<std::set<string>>(tokens[5], ",")
-                 : std::set<string>{},
-        isSet(6) ? tokenizeString<std::set<string>>(tokens[6], ",")
-                 : std::set<string>{},
+        isSet(5) ? tokenizeString<std::set<std::string>>(tokens[5], ",")
+                 : std::set<std::string>{},
+        isSet(6) ? tokenizeString<std::set<std::string>>(tokens[6], ",")
+                 : std::set<std::string>{},
         isSet(7) ? tokens[7] : "");
   }
 }
diff --git a/third_party/nix/src/libstore/machines.hh b/third_party/nix/src/libstore/machines.hh
index aef8054c250e..23712e676056 100644
--- a/third_party/nix/src/libstore/machines.hh
+++ b/third_party/nix/src/libstore/machines.hh
@@ -5,19 +5,19 @@
 namespace nix {
 
 struct Machine {
-  const string storeUri;
-  const std::vector<string> systemTypes;
-  const string sshKey;
+  const std::string storeUri;
+  const std::vector<std::string> systemTypes;
+  const std::string sshKey;
   const unsigned int maxJobs;
   const unsigned int speedFactor;
-  const std::set<string> supportedFeatures;
-  const std::set<string> mandatoryFeatures;
+  const std::set<std::string> supportedFeatures;
+  const std::set<std::string> mandatoryFeatures;
   const std::string sshPublicHostKey;
   bool enabled = true;
 
-  bool allSupported(const std::set<string>& features) const;
+  bool allSupported(const std::set<std::string>& features) const;
 
-  bool mandatoryMet(const std::set<string>& features) const;
+  bool mandatoryMet(const std::set<std::string>& features) const;
 
   Machine(decltype(storeUri)& storeUri, decltype(systemTypes)& systemTypes,
           decltype(sshKey)& sshKey, decltype(maxJobs) maxJobs,
diff --git a/third_party/nix/src/libstore/nar-accessor.cc b/third_party/nix/src/libstore/nar-accessor.cc
index 7f6e0377aed4..84bfb531ecd6 100644
--- a/third_party/nix/src/libstore/nar-accessor.cc
+++ b/third_party/nix/src/libstore/nar-accessor.cc
@@ -74,7 +74,7 @@ struct NarAccessor : public FSAccessor {
     void isExecutable() override { parents.top()->isExecutable = true; }
 
     void preallocateContents(unsigned long long size) override {
-      currentStart = string(s, pos, 16);
+      currentStart = std::string(s, pos, 16);
       assert(size <= std::numeric_limits<size_t>::max());
       parents.top()->size = (size_t)size;
       parents.top()->start = pos;
@@ -83,12 +83,12 @@ struct NarAccessor : public FSAccessor {
     void receiveContents(unsigned char* data, unsigned int len) override {
       // Sanity check
       if (!currentStart.empty()) {
-        assert(len < 16 || currentStart == string((char*)data, 16));
+        assert(len < 16 || currentStart == std::string((char*)data, 16));
         currentStart.clear();
       }
     }
 
-    void createSymlink(const Path& path, const string& target) override {
+    void createSymlink(const Path& path, const std::string& target) override {
       createMember(path,
                    NarMember{FSAccessor::Type::tSymlink, false, 0, 0, target});
     }
diff --git a/third_party/nix/src/libstore/nar-info.cc b/third_party/nix/src/libstore/nar-info.cc
index 91cf471554f3..5a217d1b617d 100644
--- a/third_party/nix/src/libstore/nar-info.cc
+++ b/third_party/nix/src/libstore/nar-info.cc
@@ -10,7 +10,7 @@ NarInfo::NarInfo(const Store& store, const std::string& s,
     throw Error(format("NAR info file '%1%' is corrupt") % whence);
   };
 
-  auto parseHashField = [&](const string& s) {
+  auto parseHashField = [&](const std::string& s) {
     try {
       return Hash(s);
     } catch (BadHash&) {
diff --git a/third_party/nix/src/libstore/optimise-store.cc b/third_party/nix/src/libstore/optimise-store.cc
index caeff72363a4..7217d54ca9af 100644
--- a/third_party/nix/src/libstore/optimise-store.cc
+++ b/third_party/nix/src/libstore/optimise-store.cc
@@ -83,7 +83,7 @@ Strings LocalStore::readDirectoryIgnoringInodes(const Path& path,
       continue;
     }
 
-    string name = dirent->d_name;
+    std::string name = dirent->d_name;
     if (name == "." || name == "..") {
       continue;
     }
@@ -271,7 +271,7 @@ void LocalStore::optimiseStore(OptimiseStats& stats) {
   }
 }
 
-static string showBytes(unsigned long long bytes) {
+static std::string showBytes(unsigned long long bytes) {
   return (format("%.2f MiB") % (bytes / (1024.0 * 1024.0))).str();
 }
 
diff --git a/third_party/nix/src/libstore/pathlocks.cc b/third_party/nix/src/libstore/pathlocks.cc
index eeee5ee1e9c9..642e64a62bac 100644
--- a/third_party/nix/src/libstore/pathlocks.cc
+++ b/third_party/nix/src/libstore/pathlocks.cc
@@ -73,12 +73,12 @@ bool lockFile(int fd, LockType lockType, bool wait) {
 
 PathLocks::PathLocks() : deletePaths(false) {}
 
-PathLocks::PathLocks(const PathSet& paths, const string& waitMsg)
+PathLocks::PathLocks(const PathSet& paths, const std::string& waitMsg)
     : deletePaths(false) {
   lockPaths(paths, waitMsg);
 }
 
-bool PathLocks::lockPaths(const PathSet& paths, const string& waitMsg,
+bool PathLocks::lockPaths(const PathSet& paths, const std::string& waitMsg,
                           bool wait) {
   assert(fds.empty());
 
diff --git a/third_party/nix/src/libstore/pathlocks.hh b/third_party/nix/src/libstore/pathlocks.hh
index 90184989cde3..201e3f01b4df 100644
--- a/third_party/nix/src/libstore/pathlocks.hh
+++ b/third_party/nix/src/libstore/pathlocks.hh
@@ -19,13 +19,13 @@ bool lockFile(int fd, LockType lockType, bool wait);
 class PathLocks {
  private:
   typedef std::pair<int, Path> FDPair;
-  list<FDPair> fds;
+  std::list<FDPair> fds;
   bool deletePaths;
 
  public:
   PathLocks();
-  PathLocks(const PathSet& paths, const string& waitMsg = "");
-  bool lockPaths(const PathSet& _paths, const string& waitMsg = "",
+  PathLocks(const PathSet& paths, const std::string& waitMsg = "");
+  bool lockPaths(const PathSet& _paths, const std::string& waitMsg = "",
                  bool wait = true);
   ~PathLocks();
   void unlock();
diff --git a/third_party/nix/src/libstore/profiles.cc b/third_party/nix/src/libstore/profiles.cc
index bdb90b7388f7..7c802d754935 100644
--- a/third_party/nix/src/libstore/profiles.cc
+++ b/third_party/nix/src/libstore/profiles.cc
@@ -19,17 +19,17 @@ static bool cmpGensByNumber(const Generation& a, const Generation& b) {
 
 /* Parse a generation name of the format
    `<profilename>-<number>-link'. */
-static int parseName(const string& profileName, const string& name) {
-  if (string(name, 0, profileName.size() + 1) != profileName + "-") {
+static int parseName(const std::string& profileName, const std::string& name) {
+  if (std::string(name, 0, profileName.size() + 1) != profileName + "-") {
     return -1;
   }
-  string s = string(name, profileName.size() + 1);
-  string::size_type p = s.find("-link");
-  if (p == string::npos) {
+  std::string s = std::string(name, profileName.size() + 1);
+  std::string::size_type p = s.find("-link");
+  if (p == std::string::npos) {
     return -1;
   }
   int n;
-  if (string2Int(string(s, 0, p), n) && n >= 0) {
+  if (string2Int(std::string(s, 0, p), n) && n >= 0) {
     return n;
   }
   return -1;
@@ -39,7 +39,7 @@ Generations findGenerations(const Path& profile, int& curGen) {
   Generations gens;
 
   Path profileDir = dirOf(profile);
-  string profileName = baseNameOf(profile);
+  std::string profileName = baseNameOf(profile);
 
   for (auto& i : readDirectory(profileDir)) {
     int n;
@@ -212,10 +212,10 @@ void deleteGenerationsOlderThan(const Path& profile, time_t t, bool dryRun) {
   }
 }
 
-void deleteGenerationsOlderThan(const Path& profile, const string& timeSpec,
-                                bool dryRun) {
+void deleteGenerationsOlderThan(const Path& profile,
+                                const std::string& timeSpec, bool dryRun) {
   time_t curTime = time(nullptr);
-  string strDays = string(timeSpec, 0, timeSpec.size() - 1);
+  std::string strDays = std::string(timeSpec, 0, timeSpec.size() - 1);
   int days;
 
   if (!string2Int(strDays, days) || days < 1) {
@@ -242,7 +242,7 @@ void lockProfile(PathLocks& lock, const Path& profile) {
   lock.setDeletion(true);
 }
 
-string optimisticLockProfile(const Path& profile) {
+std::string optimisticLockProfile(const Path& profile) {
   return pathExists(profile) ? readLink(profile) : "";
 }
 
diff --git a/third_party/nix/src/libstore/profiles.hh b/third_party/nix/src/libstore/profiles.hh
index ab31cc993af5..9f31083b32ee 100644
--- a/third_party/nix/src/libstore/profiles.hh
+++ b/third_party/nix/src/libstore/profiles.hh
@@ -15,7 +15,7 @@ struct Generation {
   operator bool() const { return number != -1; }
 };
 
-typedef list<Generation> Generations;
+typedef std::list<Generation> Generations;
 
 /* Returns the list of currently present generations for the specified
    profile, sorted by generation number. */
@@ -38,8 +38,8 @@ void deleteOldGenerations(const Path& profile, bool dryRun);
 
 void deleteGenerationsOlderThan(const Path& profile, time_t t, bool dryRun);
 
-void deleteGenerationsOlderThan(const Path& profile, const string& timeSpec,
-                                bool dryRun);
+void deleteGenerationsOlderThan(const Path& profile,
+                                const std::string& timeSpec, bool dryRun);
 
 void switchLink(const Path& link, Path target);
 
@@ -56,6 +56,6 @@ void lockProfile(PathLocks& lock, const Path& profile);
    generally cheap, since the build results are still in the Nix
    store.  Most of the time, only the user environment has to be
    rebuilt. */
-string optimisticLockProfile(const Path& profile);
+std::string optimisticLockProfile(const Path& profile);
 
 }  // namespace nix
diff --git a/third_party/nix/src/libstore/references.cc b/third_party/nix/src/libstore/references.cc
index c8cebaec08f3..6b9b7137c4e5 100644
--- a/third_party/nix/src/libstore/references.cc
+++ b/third_party/nix/src/libstore/references.cc
@@ -40,7 +40,7 @@ static void search(const unsigned char* s, size_t len, StringSet& hashes,
     if (!match) {
       continue;
     }
-    string ref((const char*)s + i, refLength);
+    std::string ref((const char*)s + i, refLength);
     if (hashes.find(ref) != hashes.end()) {
       DLOG(INFO) << "found reference to '" << ref << "' at offset " << i;
       seen.insert(ref);
@@ -55,7 +55,7 @@ struct RefScanSink : Sink {
   StringSet hashes;
   StringSet seen;
 
-  string tail;
+  std::string tail;
 
   RefScanSink() : hashSink(htSHA256) {}
 
@@ -68,34 +68,34 @@ void RefScanSink::operator()(const unsigned char* data, size_t len) {
   /* It's possible that a reference spans the previous and current
      fragment, so search in the concatenation of the tail of the
      previous fragment and the start of the current fragment. */
-  string s =
-      tail + string((const char*)data, len > refLength ? refLength : len);
+  std::string s =
+      tail + std::string((const char*)data, len > refLength ? refLength : len);
   search((const unsigned char*)s.data(), s.size(), hashes, seen);
 
   search(data, len, hashes, seen);
 
   size_t tailLen = len <= refLength ? len : refLength;
-  tail = string(tail, tail.size() < refLength - tailLen
-                          ? 0
-                          : tail.size() - (refLength - tailLen)) +
-         string((const char*)data + len - tailLen, tailLen);
+  tail = std::string(tail, tail.size() < refLength - tailLen
+                               ? 0
+                               : tail.size() - (refLength - tailLen)) +
+         std::string((const char*)data + len - tailLen, tailLen);
 }
 
-PathSet scanForReferences(const string& path, const PathSet& refs,
+PathSet scanForReferences(const std::string& path, const PathSet& refs,
                           HashResult& hash) {
   RefScanSink sink;
-  std::map<string, Path> backMap;
+  std::map<std::string, Path> backMap;
 
   /* For efficiency (and a higher hit rate), just search for the
      hash part of the file name.  (This assumes that all references
      have the form `HASH-bla'). */
   for (auto& i : refs) {
-    string baseName = baseNameOf(i);
-    string::size_type pos = baseName.find('-');
-    if (pos == string::npos) {
+    std::string baseName = baseNameOf(i);
+    std::string::size_type pos = baseName.find('-');
+    if (pos == std::string::npos) {
       throw Error(format("bad reference '%1%'") % i);
     }
-    string s = string(baseName, 0, pos);
+    std::string s = std::string(baseName, 0, pos);
     assert(s.size() == refLength);
     assert(backMap.find(s) == backMap.end());
     // parseHash(htSHA256, s);
@@ -109,7 +109,7 @@ PathSet scanForReferences(const string& path, const PathSet& refs,
   /* Map the hashes found back to their store paths. */
   PathSet found;
   for (auto& i : sink.seen) {
-    std::map<string, Path>::iterator j;
+    std::map<std::string, Path>::iterator j;
     if ((j = backMap.find(i)) == backMap.end()) {
       abort();
     }
diff --git a/third_party/nix/src/libstore/remote-store.cc b/third_party/nix/src/libstore/remote-store.cc
index cc6f6ebae993..c5d1dac6cb6c 100644
--- a/third_party/nix/src/libstore/remote-store.cc
+++ b/third_party/nix/src/libstore/remote-store.cc
@@ -102,7 +102,7 @@ ref<RemoteStore::Connection> UDSRemoteStore::openConnection() {
   }
   closeOnExec(conn->fd.get());
 
-  string socketPath = path ? *path : settings.nixDaemonSocketFile;
+  std::string socketPath = path ? *path : settings.nixDaemonSocketFile;
 
   struct sockaddr_un addr;
   addr.sun_family = AF_UNIX;
@@ -412,7 +412,7 @@ PathSet RemoteStore::queryDerivationOutputNames(const Path& path) {
   return readStrings<PathSet>(conn->from);
 }
 
-Path RemoteStore::queryPathFromHashPart(const string& hashPart) {
+Path RemoteStore::queryPathFromHashPart(const std::string& hashPart) {
   auto conn(getConnection());
   conn->to << wopQueryPathFromHashPart << hashPart;
   conn.processStderr();
@@ -460,7 +460,7 @@ void RemoteStore::addToStore(const ValidPathInfo& info, Source& source,
   }
 }
 
-Path RemoteStore::addToStore(const string& name, const Path& _srcPath,
+Path RemoteStore::addToStore(const std::string& name, const Path& _srcPath,
                              bool recursive, HashType hashAlgo,
                              PathFilter& filter, RepairFlag repair) {
   if (repair != 0u) {
@@ -503,7 +503,7 @@ Path RemoteStore::addToStore(const string& name, const Path& _srcPath,
   return readStorePath(*this, conn->from);
 }
 
-Path RemoteStore::addTextToStore(const string& name, const string& s,
+Path RemoteStore::addTextToStore(const std::string& name, const std::string& s,
                                  const PathSet& references, RepairFlag repair) {
   if (repair != 0u) {
     throw Error(
@@ -537,7 +537,7 @@ void RemoteStore::buildPaths(const PathSet& drvPaths, BuildMode buildMode) {
        identifiers. */
     PathSet drvPaths2;
     for (auto& i : drvPaths) {
-      drvPaths2.insert(string(i, 0, i.find('!')));
+      drvPaths2.insert(std::string(i, 0, i.find('!')));
     }
     conn->to << drvPaths2;
   }
@@ -692,7 +692,7 @@ std::exception_ptr RemoteStore::Connection::processStderr(Sink* sink,
     auto msg = readNum<uint64_t>(from);
 
     if (msg == STDERR_WRITE) {
-      string s = readString(from);
+      std::string s = readString(from);
       if (sink == nullptr) {
         throw Error("no sink");
       }
@@ -710,7 +710,7 @@ std::exception_ptr RemoteStore::Connection::processStderr(Sink* sink,
     }
 
     else if (msg == STDERR_ERROR) {
-      string error = readString(from);
+      std::string error = readString(from);
       unsigned int status = readInt(from);
       return std::make_exception_ptr(Error(status, error));
     }
diff --git a/third_party/nix/src/libstore/remote-store.hh b/third_party/nix/src/libstore/remote-store.hh
index dc44cd32ac47..e61e72892c34 100644
--- a/third_party/nix/src/libstore/remote-store.hh
+++ b/third_party/nix/src/libstore/remote-store.hh
@@ -52,7 +52,7 @@ class RemoteStore : public virtual Store {
 
   StringSet queryDerivationOutputNames(const Path& path) override;
 
-  Path queryPathFromHashPart(const string& hashPart) override;
+  Path queryPathFromHashPart(const std::string& hashPart) override;
 
   PathSet querySubstitutablePaths(const PathSet& paths) override;
 
@@ -63,12 +63,12 @@ class RemoteStore : public virtual Store {
                   CheckSigsFlag checkSigs,
                   std::shared_ptr<FSAccessor> accessor) override;
 
-  Path addToStore(const string& name, const Path& srcPath,
+  Path addToStore(const std::string& name, const Path& srcPath,
                   bool recursive = true, HashType hashAlgo = htSHA256,
                   PathFilter& filter = defaultPathFilter,
                   RepairFlag repair = NoRepair) override;
 
-  Path addTextToStore(const string& name, const string& s,
+  Path addTextToStore(const std::string& name, const std::string& s,
                       const PathSet& references, RepairFlag repair) override;
 
   void buildPaths(const PathSet& paths, BuildMode buildMode) override;
diff --git a/third_party/nix/src/libstore/s3-binary-cache-store.cc b/third_party/nix/src/libstore/s3-binary-cache-store.cc
index df3afab3cf32..2b25fd874437 100644
--- a/third_party/nix/src/libstore/s3-binary-cache-store.cc
+++ b/third_party/nix/src/libstore/s3-binary-cache-store.cc
@@ -77,8 +77,8 @@ static void initAWS() {
   });
 }
 
-S3Helper::S3Helper(const string& profile, const string& region,
-                   const string& scheme, const string& endpoint)
+S3Helper::S3Helper(const std::string& profile, const std::string& region,
+                   const std::string& scheme, const std::string& endpoint)
     : config(makeConfig(region, scheme, endpoint)),
       client(make_ref<Aws::S3::S3Client>(
           profile == ""
@@ -114,7 +114,8 @@ class RetryStrategy : public Aws::Client::DefaultRetryStrategy {
 };
 
 ref<Aws::Client::ClientConfiguration> S3Helper::makeConfig(
-    const string& region, const string& scheme, const string& endpoint) {
+    const std::string& region, const std::string& scheme,
+    const std::string& endpoint) {
   initAWS();
   auto res = make_ref<Aws::Client::ClientConfiguration>();
   res->region = region;
diff --git a/third_party/nix/src/libstore/sqlite.cc b/third_party/nix/src/libstore/sqlite.cc
index 2dea952d0275..dbdaa29d4fd9 100644
--- a/third_party/nix/src/libstore/sqlite.cc
+++ b/third_party/nix/src/libstore/sqlite.cc
@@ -54,7 +54,7 @@ void SQLite::exec(const std::string& stmt) {
   });
 }
 
-void SQLiteStmt::create(sqlite3* db, const string& sql) {
+void SQLiteStmt::create(sqlite3* db, const std::string& sql) {
   checkInterrupt();
   assert(!stmt);
   if (sqlite3_prepare_v2(db, sql.c_str(), -1, &stmt, nullptr) != SQLITE_OK) {
diff --git a/third_party/nix/src/libstore/store-api.cc b/third_party/nix/src/libstore/store-api.cc
index 50e9b3b6ea86..e6891395cdc5 100644
--- a/third_party/nix/src/libstore/store-api.cc
+++ b/third_party/nix/src/libstore/store-api.cc
@@ -48,7 +48,7 @@ Path Store::followLinksToStore(const Path& _path) const {
     if (!isLink(path)) {
       break;
     }
-    string target = readLink(path);
+    std::string target = readLink(path);
     path = absPath(target, dirOf(path));
   }
   if (!isInStore(path)) {
@@ -61,22 +61,23 @@ Path Store::followLinksToStorePath(const Path& path) const {
   return toStorePath(followLinksToStore(path));
 }
 
-string storePathToName(const Path& path) {
+std::string storePathToName(const Path& path) {
   auto base = baseNameOf(path);
   assert(base.size() == storePathHashLen ||
          (base.size() > storePathHashLen && base[storePathHashLen] == '-'));
-  return base.size() == storePathHashLen ? ""
-                                         : string(base, storePathHashLen + 1);
+  return base.size() == storePathHashLen
+             ? ""
+             : std::string(base, storePathHashLen + 1);
 }
 
-string storePathToHash(const Path& path) {
+std::string storePathToHash(const Path& path) {
   auto base = baseNameOf(path);
   assert(base.size() >= storePathHashLen);
-  return string(base, 0, storePathHashLen);
+  return std::string(base, 0, storePathHashLen);
 }
 
-void checkStoreName(const string& name) {
-  string validChars = "+-._?=";
+void checkStoreName(const std::string& name) {
+  std::string validChars = "+-._?=";
 
   auto baseError =
       format(
@@ -90,7 +91,7 @@ void checkStoreName(const string& name) {
 
   /* Disallow names starting with a dot for possible security
      reasons (e.g., "." and ".."). */
-  if (string(name, 0, 1) == ".") {
+  if (std::string(name, 0, 1) == ".") {
     throw Error(baseError % "it is illegal to start the name with a period");
   }
   /* Disallow names longer than 211 characters. ext4’s max is 256,
@@ -100,7 +101,7 @@ void checkStoreName(const string& name) {
   }
   for (auto& i : name) {
     if (!((i >= 'A' && i <= 'Z') || (i >= 'a' && i <= 'z') ||
-          (i >= '0' && i <= '9') || validChars.find(i) != string::npos)) {
+          (i >= '0' && i <= '9') || validChars.find(i) != std::string::npos)) {
       throw Error(baseError % (format("the '%1%' character is invalid") % i));
     }
   }
@@ -176,10 +177,11 @@ void checkStoreName(const string& name) {
    "source:".
 */
 
-Path Store::makeStorePath(const string& type, const Hash& hash,
-                          const string& name) const {
+Path Store::makeStorePath(const std::string& type, const Hash& hash,
+                          const std::string& name) const {
   /* e.g., "source:sha256:1abc...:/nix/store:foo.tar.gz" */
-  string s = type + ":" + hash.to_string(Base16) + ":" + storeDir + ":" + name;
+  std::string s =
+      type + ":" + hash.to_string(Base16) + ":" + storeDir + ":" + name;
 
   checkStoreName(name);
 
@@ -188,31 +190,32 @@ Path Store::makeStorePath(const string& type, const Hash& hash,
          "-" + name;
 }
 
-Path Store::makeOutputPath(const string& id, const Hash& hash,
-                           const string& name) const {
+Path Store::makeOutputPath(const std::string& id, const Hash& hash,
+                           const std::string& name) const {
   return makeStorePath("output:" + id, hash,
                        name + (id == "out" ? "" : "-" + id));
 }
 
 Path Store::makeFixedOutputPath(bool recursive, const Hash& hash,
-                                const string& name) const {
+                                const std::string& name) const {
   return hash.type == htSHA256 && recursive
              ? makeStorePath("source", hash, name)
              : makeStorePath(
                    "output:out",
-                   hashString(htSHA256,
-                              "fixed:out:" + (recursive ? (string) "r:" : "") +
-                                  hash.to_string(Base16) + ":"),
+                   hashString(
+                       htSHA256,
+                       "fixed:out:" + (recursive ? (std::string) "r:" : "") +
+                           hash.to_string(Base16) + ":"),
                    name);
 }
 
-Path Store::makeTextPath(const string& name, const Hash& hash,
+Path Store::makeTextPath(const std::string& name, const Hash& hash,
                          const PathSet& references) const {
   assert(hash.type == htSHA256);
   /* Stuff the references (if any) into the type.  This is a bit
      hacky, but we can't put them in `s' since that would be
      ambiguous. */
-  string type = "text";
+  std::string type = "text";
   for (auto& i : references) {
     type += ":";
     type += i;
@@ -220,7 +223,7 @@ Path Store::makeTextPath(const string& name, const Hash& hash,
   return makeStorePath(type, hash, name);
 }
 
-std::pair<Path, Hash> Store::computeStorePathForPath(const string& name,
+std::pair<Path, Hash> Store::computeStorePathForPath(const std::string& name,
                                                      const Path& srcPath,
                                                      bool recursive,
                                                      HashType hashAlgo,
@@ -231,7 +234,8 @@ std::pair<Path, Hash> Store::computeStorePathForPath(const string& name,
   return std::pair<Path, Hash>(dstPath, h);
 }
 
-Path Store::computeStorePathForText(const string& name, const string& s,
+Path Store::computeStorePathForText(const std::string& name,
+                                    const std::string& s,
                                     const PathSet& references) const {
   return makeTextPath(name, hashString(htSHA256, s), references);
 }
@@ -428,9 +432,9 @@ PathSet Store::queryValidPaths(const PathSet& paths,
 /* Return a string accepted by decodeValidPathInfo() that
    registers the specified paths as valid.  Note: it's the
    responsibility of the caller to provide a closure. */
-string Store::makeValidityRegistration(const PathSet& paths, bool showDerivers,
-                                       bool showHash) {
-  string s = s;
+std::string Store::makeValidityRegistration(const PathSet& paths,
+                                            bool showDerivers, bool showHash) {
+  std::string s = s;
 
   for (auto& i : paths) {
     s += i + "\n";
@@ -710,7 +714,7 @@ ValidPathInfo decodeValidPathInfo(std::istream& str, bool hashGiven) {
     return info;
   }
   if (hashGiven) {
-    string s;
+    std::string s;
     getline(str, s);
     info.narHash = Hash(s, htSHA256);
     getline(str, s);
@@ -719,7 +723,7 @@ ValidPathInfo decodeValidPathInfo(std::istream& str, bool hashGiven) {
     }
   }
   getline(str, info.deriver);
-  string s;
+  std::string s;
   int n;
   getline(str, s);
   if (!string2Int(s, n)) {
@@ -735,8 +739,8 @@ ValidPathInfo decodeValidPathInfo(std::istream& str, bool hashGiven) {
   return info;
 }
 
-string showPaths(const PathSet& paths) {
-  string s;
+std::string showPaths(const PathSet& paths) {
+  std::string s;
   for (auto& i : paths) {
     if (!s.empty()) {
       s += ", ";
diff --git a/third_party/nix/src/libstore/store-api.hh b/third_party/nix/src/libstore/store-api.hh
index 242a3e65621e..cf2520c6ca98 100644
--- a/third_party/nix/src/libstore/store-api.hh
+++ b/third_party/nix/src/libstore/store-api.hh
@@ -18,12 +18,14 @@
 
 namespace nix {
 
-MakeError(SubstError, Error)
-    MakeError(BuildError, Error) /* denotes a permanent build failure */
-    MakeError(InvalidPath, Error) MakeError(Unsupported, Error)
-        MakeError(SubstituteGone, Error) MakeError(SubstituterDisabled, Error)
-
-            struct BasicDerivation;
+MakeError(SubstError, Error);
+MakeError(BuildError, Error); /* denotes a permanent build failure */
+MakeError(InvalidPath, Error);
+MakeError(Unsupported, Error);
+MakeError(SubstituteGone, Error);
+MakeError(SubstituterDisabled, Error);
+
+struct BasicDerivation;
 struct Derivation;
 class FSAccessor;
 class NarInfoDiskCache;
@@ -175,7 +177,7 @@ struct ValidPathInfo {
   virtual ~ValidPathInfo() {}
 };
 
-typedef list<ValidPathInfo> ValidPathInfos;
+typedef std::list<ValidPathInfo> ValidPathInfos;
 
 enum BuildMode { bmNormal, bmRepair, bmCheck };
 
@@ -274,23 +276,23 @@ class Store : public std::enable_shared_from_this<Store>, public Config {
   Path followLinksToStorePath(const Path& path) const;
 
   /* Constructs a unique store path name. */
-  Path makeStorePath(const string& type, const Hash& hash,
-                     const string& name) const;
+  Path makeStorePath(const std::string& type, const Hash& hash,
+                     const std::string& name) const;
 
-  Path makeOutputPath(const string& id, const Hash& hash,
-                      const string& name) const;
+  Path makeOutputPath(const std::string& id, const Hash& hash,
+                      const std::string& name) const;
 
   Path makeFixedOutputPath(bool recursive, const Hash& hash,
-                           const string& name) const;
+                           const std::string& name) const;
 
-  Path makeTextPath(const string& name, const Hash& hash,
+  Path makeTextPath(const std::string& name, const Hash& hash,
                     const PathSet& references) const;
 
   /* This is the preparatory part of addToStore(); it computes the
      store path to which srcPath is to be copied.  Returns the store
      path and the cryptographic hash of the contents of srcPath. */
   std::pair<Path, Hash> computeStorePathForPath(
-      const string& name, const Path& srcPath, bool recursive = true,
+      const std::string& name, const Path& srcPath, bool recursive = true,
       HashType hashAlgo = htSHA256,
       PathFilter& filter = defaultPathFilter) const;
 
@@ -308,7 +310,7 @@ class Store : public std::enable_shared_from_this<Store>, public Config {
      simply yield a different store path, so other users wouldn't be
      affected), but it has some backwards compatibility issues (the
      hashing scheme changes), so I'm not doing that for now. */
-  Path computeStorePathForText(const string& name, const string& s,
+  Path computeStorePathForText(const std::string& name, const std::string& s,
                                const PathSet& references) const;
 
   /* Check whether a path is valid. */
@@ -368,7 +370,7 @@ class Store : public std::enable_shared_from_this<Store>, public Config {
 
   /* Query the full store path given the hash part of a valid store
      path, or "" if the path doesn't exist. */
-  virtual Path queryPathFromHashPart(const string& hashPart) = 0;
+  virtual Path queryPathFromHashPart(const std::string& hashPart) = 0;
 
   /* Query which of the given paths have substitutes. */
   virtual PathSet querySubstitutablePaths(const PathSet& paths) { return {}; };
@@ -400,14 +402,14 @@ class Store : public std::enable_shared_from_this<Store>, public Config {
      validity the resulting path.  The resulting path is returned.
      The function object `filter' can be used to exclude files (see
      libutil/archive.hh). */
-  virtual Path addToStore(const string& name, const Path& srcPath,
+  virtual Path addToStore(const std::string& name, const Path& srcPath,
                           bool recursive = true, HashType hashAlgo = htSHA256,
                           PathFilter& filter = defaultPathFilter,
                           RepairFlag repair = NoRepair) = 0;
 
   /* Like addToStore, but the contents written to the output path is
      a regular file containing the given string. */
-  virtual Path addTextToStore(const string& name, const string& s,
+  virtual Path addTextToStore(const std::string& name, const std::string& s,
                               const PathSet& references,
                               RepairFlag repair = NoRepair) = 0;
 
@@ -484,8 +486,8 @@ class Store : public std::enable_shared_from_this<Store>, public Config {
   /* Return a string representing information about the path that
      can be loaded into the database using `nix-store --load-db' or
      `nix-store --register-validity'. */
-  string makeValidityRegistration(const PathSet& paths, bool showDerivers,
-                                  bool showHash);
+  std::string makeValidityRegistration(const PathSet& paths, bool showDerivers,
+                                       bool showHash);
 
   /* Write a JSON representation of store path metadata, such as the
      hash and the references. If ‘includeImpureInfo’ is true,
@@ -637,7 +639,7 @@ class LocalFSStore : public virtual Store {
       rootDir != "" ? rootDir + "/nix/var/log/nix" : settings.nixLogDir, "log",
       "directory where Nix will store state"};
 
-  const static string drvsLogDir;
+  const static std::string drvsLogDir;
 
   LocalFSStore(const Params& params);
 
@@ -660,15 +662,15 @@ class LocalFSStore : public virtual Store {
 };
 
 /* Extract the name part of the given store path. */
-string storePathToName(const Path& path);
+std::string storePathToName(const Path& path);
 
 /* Extract the hash part of the given store path. */
-string storePathToHash(const Path& path);
+std::string storePathToHash(const Path& path);
 
 /* Check whether ‘name’ is a valid store path name part, i.e. contains
    only the characters [a-zA-Z0-9\+\-\.\_\?\=] and doesn't start with
    a dot. */
-void checkStoreName(const string& name);
+void checkStoreName(const std::string& name);
 
 /* Copy a path from one store to another. */
 void copyStorePath(ref<Store> srcStore, const ref<Store>& dstStore,
@@ -756,7 +758,7 @@ struct RegisterStoreImplementation {
 
 /* Display a set of paths in human-readable form (i.e., between quotes
    and separated by commas). */
-string showPaths(const PathSet& paths);
+std::string showPaths(const PathSet& paths);
 
 ValidPathInfo decodeValidPathInfo(std::istream& str, bool hashGiven = false);
 
diff --git a/third_party/nix/src/libutil/archive.cc b/third_party/nix/src/libutil/archive.cc
index 32bad07f22da..f78727c5fb46 100644
--- a/third_party/nix/src/libutil/archive.cc
+++ b/third_party/nix/src/libutil/archive.cc
@@ -38,7 +38,7 @@ static GlobalConfig::Register r1(&archiveSettings);
 
 const std::string narVersionMagic1 = "nix-archive-1";
 
-static string caseHackSuffix = "~nix~case~hack~";
+static std::string caseHackSuffix = "~nix~case~hack~";
 
 PathFilter defaultPathFilter = [](const Path& /*unused*/) { return true; };
 
@@ -89,12 +89,12 @@ static void dump(const Path& path, Sink& sink, PathFilter& filter) {
 
     /* If we're on a case-insensitive system like macOS, undo
        the case hack applied by restorePath(). */
-    std::map<string, string> unhacked;
+    std::map<std::string, std::string> unhacked;
     for (auto& i : readDirectory(path)) {
       if (archiveSettings.useCaseHack) {
-        string name(i.name);
+        std::string name(i.name);
         size_t pos = i.name.find(caseHackSuffix);
-        if (pos != string::npos) {
+        if (pos != std::string::npos) {
           DLOG(INFO) << "removing case hack suffix from " << path << "/"
                      << i.name;
 
@@ -145,7 +145,7 @@ void dumpString(const std::string& s, Sink& sink) {
        << "contents" << s << ")";
 }
 
-static SerialisationError badArchive(const string& s) {
+static SerialisationError badArchive(const std::string& s) {
   return SerialisationError("bad archive: " + s);
 }
 
@@ -182,13 +182,13 @@ static void parseContents(ParseSink& sink, Source& source, const Path& path) {
 }
 
 struct CaseInsensitiveCompare {
-  bool operator()(const string& a, const string& b) const {
+  bool operator()(const std::string& a, const std::string& b) const {
     return strcasecmp(a.c_str(), b.c_str()) < 0;
   }
 };
 
 static void parse(ParseSink& sink, Source& source, const Path& path) {
-  string s;
+  std::string s;
 
   s = readString(source);
   if (s != "(") {
@@ -212,7 +212,7 @@ static void parse(ParseSink& sink, Source& source, const Path& path) {
       if (type != tpUnknown) {
         throw badArchive("multiple type fields");
       }
-      string t = readString(source);
+      std::string t = readString(source);
 
       if (t == "regular") {
         type = tpRegular;
@@ -247,8 +247,8 @@ static void parse(ParseSink& sink, Source& source, const Path& path) {
     }
 
     else if (s == "entry" && type == tpDirectory) {
-      string name;
-      string prevName;
+      std::string name;
+      std::string prevName;
 
       s = readString(source);
       if (s != "(") {
@@ -266,8 +266,8 @@ static void parse(ParseSink& sink, Source& source, const Path& path) {
         if (s == "name") {
           name = readString(source);
           if (name.empty() || name == "." || name == ".." ||
-              name.find('/') != string::npos ||
-              name.find((char)0) != string::npos) {
+              name.find('/') != std::string::npos ||
+              name.find((char)0) != std::string::npos) {
             throw Error(format("NAR contains invalid file name '%1%'") % name);
           }
           if (name <= prevName) {
@@ -297,7 +297,7 @@ static void parse(ParseSink& sink, Source& source, const Path& path) {
     }
 
     else if (s == "target" && type == tpSymlink) {
-      string target = readString(source);
+      std::string target = readString(source);
       sink.createSymlink(path, target);
     }
 
@@ -308,7 +308,7 @@ static void parse(ParseSink& sink, Source& source, const Path& path) {
 }
 
 void parseDump(ParseSink& sink, Source& source) {
-  string version;
+  std::string version;
   try {
     version = readString(source, narVersionMagic1.size());
   } catch (SerialisationError& e) {
@@ -369,7 +369,7 @@ struct RestoreSink : ParseSink {
     writeFull(fd.get(), data, len);
   }
 
-  void createSymlink(const Path& path, const string& target) override {
+  void createSymlink(const Path& path, const std::string& target) override {
     Path p = dstPath + path;
     nix::createSymlink(target, p);
   }
diff --git a/third_party/nix/src/libutil/archive.hh b/third_party/nix/src/libutil/archive.hh
index 9a656edae4a3..0afa8893efdd 100644
--- a/third_party/nix/src/libutil/archive.hh
+++ b/third_party/nix/src/libutil/archive.hh
@@ -56,7 +56,7 @@ struct ParseSink {
   virtual void preallocateContents(unsigned long long size){};
   virtual void receiveContents(unsigned char* data, unsigned int len){};
 
-  virtual void createSymlink(const Path& path, const string& target){};
+  virtual void createSymlink(const Path& path, const std::string& target){};
 };
 
 struct TeeSink : ParseSink {
diff --git a/third_party/nix/src/libutil/args.cc b/third_party/nix/src/libutil/args.cc
index 48fa715fdf0f..4e7bcb3ae72b 100644
--- a/third_party/nix/src/libutil/args.cc
+++ b/third_party/nix/src/libutil/args.cc
@@ -27,14 +27,14 @@ void Args::parseCmdline(const Strings& _cmdline) {
        `-j3` -> `-j 3`). */
     if (!dashDash && arg.length() > 2 && arg[0] == '-' && arg[1] != '-' &&
         (isalpha(arg[1]) != 0)) {
-      *pos = (string) "-" + arg[1];
+      *pos = (std::string) "-" + arg[1];
       auto next = pos;
       ++next;
       for (unsigned int j = 2; j < arg.length(); j++) {
         if (isalpha(arg[j]) != 0) {
-          cmdline.insert(next, (string) "-" + arg[j]);
+          cmdline.insert(next, (std::string) "-" + arg[j]);
         } else {
-          cmdline.insert(next, string(arg, j));
+          cmdline.insert(next, std::string(arg, j));
           break;
         }
       }
@@ -59,7 +59,7 @@ void Args::parseCmdline(const Strings& _cmdline) {
   processArgs(pendingArgs, true);
 }
 
-void Args::printHelp(const string& programName, std::ostream& out) {
+void Args::printHelp(const std::string& programName, std::ostream& out) {
   std::cout << "Usage: " << programName << " <FLAGS>...";
   for (auto& exp : expectedArgs) {
     std::cout << renderLabels({exp.label});
@@ -121,15 +121,15 @@ bool Args::processFlag(Strings::iterator& pos, Strings::iterator end) {
     return true;
   };
 
-  if (string(*pos, 0, 2) == "--") {
-    auto i = longFlags.find(string(*pos, 2));
+  if (std::string(*pos, 0, 2) == "--") {
+    auto i = longFlags.find(std::string(*pos, 2));
     if (i == longFlags.end()) {
       return false;
     }
     return process("--" + i->first, *i->second);
   }
 
-  if (string(*pos, 0, 1) == "-" && pos->size() == 2) {
+  if (std::string(*pos, 0, 1) == "-" && pos->size() == 2) {
     auto c = (*pos)[1];
     auto i = shortFlags.find(c);
     if (i == shortFlags.end()) {
diff --git a/third_party/nix/src/libutil/args.hh b/third_party/nix/src/libutil/args.hh
index 20233d353424..20a6379fecba 100644
--- a/third_party/nix/src/libutil/args.hh
+++ b/third_party/nix/src/libutil/args.hh
@@ -18,7 +18,7 @@ class Args {
      wrong. */
   void parseCmdline(const Strings& cmdline);
 
-  virtual void printHelp(const string& programName, std::ostream& out);
+  virtual void printHelp(const std::string& programName, std::ostream& out);
 
   virtual std::string description() { return ""; }
 
@@ -187,7 +187,7 @@ class Args {
   }
 
   /* Expect a string argument. */
-  void expectArg(const std::string& label, string* dest,
+  void expectArg(const std::string& label, std::string* dest,
                  bool optional = false) {
     expectedArgs.push_back(
         ExpectedArg{label, 1, optional,
diff --git a/third_party/nix/src/libutil/config.cc b/third_party/nix/src/libutil/config.cc
index 828ee1811bdb..c7c952abf16f 100644
--- a/third_party/nix/src/libutil/config.cc
+++ b/third_party/nix/src/libutil/config.cc
@@ -82,23 +82,23 @@ void Config::getSettings(std::map<std::string, SettingInfo>& res,
 
 void AbstractConfig::applyConfigFile(const Path& path) {
   try {
-    string contents = readFile(path);
+    std::string contents = readFile(path);
 
     unsigned int pos = 0;
 
     while (pos < contents.size()) {
-      string line;
+      std::string line;
       while (pos < contents.size() && contents[pos] != '\n') {
         line += contents[pos++];
       }
       pos++;
 
-      string::size_type hash = line.find('#');
-      if (hash != string::npos) {
-        line = string(line, 0, hash);
+      std::string::size_type hash = line.find('#');
+      if (hash != std::string::npos) {
+        line = std::string(line, 0, hash);
       }
 
-      auto tokens = tokenizeString<vector<string> >(line);
+      auto tokens = tokenizeString<std::vector<std::string> >(line);
       if (tokens.empty()) {
         continue;
       }
@@ -136,7 +136,7 @@ void AbstractConfig::applyConfigFile(const Path& path) {
                          path);
       }
 
-      string name = tokens[0];
+      std::string name = tokens[0];
 
       auto i = tokens.begin();
       advance(i, 2);
diff --git a/third_party/nix/src/libutil/hash.cc b/third_party/nix/src/libutil/hash.cc
index 81d8628e972b..07a9730551da 100644
--- a/third_party/nix/src/libutil/hash.cc
+++ b/third_party/nix/src/libutil/hash.cc
@@ -63,26 +63,26 @@ bool Hash::operator<(const Hash& h) const {
   return false;
 }
 
-const string base16Chars = "0123456789abcdef";
+const std::string base16Chars = "0123456789abcdef";
 
-static string printHash16(const Hash& hash) {
+static std::string printHash16(const Hash& hash) {
   char buf[hash.hashSize * 2];
   for (unsigned int i = 0; i < hash.hashSize; i++) {
     buf[i * 2] = base16Chars[hash.hash[i] >> 4];
     buf[i * 2 + 1] = base16Chars[hash.hash[i] & 0x0f];
   }
-  return string(buf, hash.hashSize * 2);
+  return std::string(buf, hash.hashSize * 2);
 }
 
 // omitted: E O U T
-const string base32Chars = "0123456789abcdfghijklmnpqrsvwxyz";
+const std::string base32Chars = "0123456789abcdfghijklmnpqrsvwxyz";
 
-static string printHash32(const Hash& hash) {
+static std::string printHash32(const Hash& hash) {
   assert(hash.hashSize);
   size_t len = hash.base32Len();
   assert(len);
 
-  string s;
+  std::string s;
   s.reserve(len);
 
   for (int n = (int)len - 1; n >= 0; n--) {
@@ -98,7 +98,7 @@ static string printHash32(const Hash& hash) {
   return s;
 }
 
-string printHash16or32(const Hash& hash) {
+std::string printHash16or32(const Hash& hash) {
   return hash.to_string(hash.type == htMD5 ? Base16 : Base32, false);
 }
 
@@ -128,17 +128,17 @@ Hash::Hash(const std::string& s, HashType type) : type(type) {
   bool isSRI = false;
 
   auto sep = s.find(':');
-  if (sep == string::npos) {
+  if (sep == std::string::npos) {
     sep = s.find('-');
-    if (sep != string::npos) {
+    if (sep != std::string::npos) {
       isSRI = true;
     } else if (type == htUnknown) {
       throw BadHash("hash '%s' does not include a type", s);
     }
   }
 
-  if (sep != string::npos) {
-    string hts = string(s, 0, sep);
+  if (sep != std::string::npos) {
+    std::string hts = std::string(s, 0, sep);
     this->type = parseHashType(hts);
     if (this->type == htUnknown) {
       throw BadHash("unknown hash type '%s'", hts);
@@ -259,7 +259,7 @@ static void finish(HashType ht, Ctx& ctx, unsigned char* hash) {
   }
 }
 
-Hash hashString(HashType ht, const string& s) {
+Hash hashString(HashType ht, const std::string& s) {
   Ctx ctx;
   Hash hash(ht);
   start(ht, ctx);
@@ -338,7 +338,7 @@ Hash compressHash(const Hash& hash, unsigned int newSize) {
   return h;
 }
 
-HashType parseHashType(const string& s) {
+HashType parseHashType(const std::string& s) {
   if (s == "md5") {
     return htMD5;
   }
@@ -353,7 +353,7 @@ HashType parseHashType(const string& s) {
   }
 }
 
-string printHashType(HashType ht) {
+std::string printHashType(HashType ht) {
   if (ht == htMD5) {
     return "md5";
   }
diff --git a/third_party/nix/src/libutil/hash.hh b/third_party/nix/src/libutil/hash.hh
index a9002023fa31..f9c63c155ead 100644
--- a/third_party/nix/src/libutil/hash.hh
+++ b/third_party/nix/src/libutil/hash.hh
@@ -14,7 +14,7 @@ const int sha1HashSize = 20;
 const int sha256HashSize = 32;
 const int sha512HashSize = 64;
 
-extern const string base32Chars;
+extern const std::string base32Chars;
 
 enum Base : int { Base64, Base32, Base16, SRI };
 
@@ -68,10 +68,10 @@ struct Hash {
 };
 
 /* Print a hash in base-16 if it's MD5, or base-32 otherwise. */
-string printHash16or32(const Hash& hash);
+std::string printHash16or32(const Hash& hash);
 
 /* Compute the hash of the given string. */
-Hash hashString(HashType ht, const string& s);
+Hash hashString(HashType ht, const std::string& s);
 
 /* Compute the hash of the given file. */
 Hash hashFile(HashType ht, const Path& path);
@@ -87,10 +87,10 @@ HashResult hashPath(HashType ht, const Path& path,
 Hash compressHash(const Hash& hash, unsigned int newSize);
 
 /* Parse a string representing a hash type. */
-HashType parseHashType(const string& s);
+HashType parseHashType(const std::string& s);
 
 /* And the reverse. */
-string printHashType(HashType ht);
+std::string printHashType(HashType ht);
 
 union Ctx;
 
diff --git a/third_party/nix/src/libutil/serialise.cc b/third_party/nix/src/libutil/serialise.cc
index 34af4e840ab6..52f0b5542601 100644
--- a/third_party/nix/src/libutil/serialise.cc
+++ b/third_party/nix/src/libutil/serialise.cc
@@ -223,7 +223,7 @@ void writeString(const unsigned char* buf, size_t len, Sink& sink) {
   writePadding(len, sink);
 }
 
-Sink& operator<<(Sink& sink, const string& s) {
+Sink& operator<<(Sink& sink, const std::string& s) {
   writeString((const unsigned char*)s.data(), s.size(), sink);
   return sink;
 }
@@ -269,7 +269,7 @@ size_t readString(unsigned char* buf, size_t max, Source& source) {
   return len;
 }
 
-string readString(Source& source, size_t max) {
+std::string readString(Source& source, size_t max) {
   auto len = readNum<size_t>(source);
   if (len > max) {
     throw SerialisationError("string is too long");
@@ -280,7 +280,7 @@ string readString(Source& source, size_t max) {
   return res;
 }
 
-Source& operator>>(Source& in, string& s) {
+Source& operator>>(Source& in, std::string& s) {
   s = readString(in);
   return in;
 }
diff --git a/third_party/nix/src/libutil/serialise.hh b/third_party/nix/src/libutil/serialise.hh
index a5992b50ec6e..dc877487ee7e 100644
--- a/third_party/nix/src/libutil/serialise.hh
+++ b/third_party/nix/src/libutil/serialise.hh
@@ -135,9 +135,9 @@ struct StringSink : Sink {
 
 /* A source that reads data from a string. */
 struct StringSource : Source {
-  const string& s;
+  const std::string& s;
   size_t pos;
-  StringSource(const string& _s) : s(_s), pos(0) {}
+  StringSource(const std::string& _s) : s(_s), pos(0) {}
   size_t read(unsigned char* data, size_t len) override;
 };
 
@@ -231,7 +231,7 @@ inline Sink& operator<<(Sink& sink, uint64_t n) {
   return sink;
 }
 
-Sink& operator<<(Sink& sink, const string& s);
+Sink& operator<<(Sink& sink, const std::string& s);
 Sink& operator<<(Sink& sink, const Strings& s);
 Sink& operator<<(Sink& sink, const StringSet& s);
 
@@ -265,12 +265,12 @@ inline uint64_t readLongLong(Source& source) {
 
 void readPadding(size_t len, Source& source);
 size_t readString(unsigned char* buf, size_t max, Source& source);
-string readString(Source& source,
-                  size_t max = std::numeric_limits<size_t>::max());
+std::string readString(Source& source,
+                       size_t max = std::numeric_limits<size_t>::max());
 template <class T>
 T readStrings(Source& source);
 
-Source& operator>>(Source& in, string& s);
+Source& operator>>(Source& in, std::string& s);
 
 template <typename T>
 Source& operator>>(Source& in, T& n) {
diff --git a/third_party/nix/src/libutil/types.hh b/third_party/nix/src/libutil/types.hh
index ac1b802ce0f1..ad44719afe3a 100644
--- a/third_party/nix/src/libutil/types.hh
+++ b/third_party/nix/src/libutil/types.hh
@@ -22,10 +22,6 @@ namespace nix {
 
 /* Inherit some names from other namespaces for convenience. */
 using boost::format;
-using std::list;
-using std::set;
-using std::string;
-using std::vector;
 
 /* A variadic template that does nothing. Useful to call a function
    for all variadic arguments but ignoring the result. */
@@ -35,8 +31,8 @@ struct nop {
 };
 
 struct FormatOrString {
-  string s;
-  FormatOrString(const string& s) : s(s){};
+  std::string s;
+  FormatOrString(const std::string& s) : s(s){};
   FormatOrString(const format& f) : s(f.str()){};
   FormatOrString(const char* s) : s(s){};
 };
@@ -64,8 +60,8 @@ inline std::string fmt(const std::string& fs, Args... args) {
    a subclass. Catch Error instead. */
 class BaseError : public std::exception {
  protected:
-  string prefix_;  // used for location traces etc.
-  string err;
+  std::string prefix_;  // used for location traces etc.
+  std::string err;
 
  public:
   unsigned int status = 1;  // exit status
@@ -84,8 +80,8 @@ class BaseError : public std::exception {
   const char* what() const noexcept { return err.c_str(); }
 #endif
 
-  const string& msg() const { return err; }
-  const string& prefix() const { return prefix_; }
+  const std::string& msg() const { return err; }
+  const std::string& prefix() const { return prefix_; }
   BaseError& addPrefix(const FormatOrString& fs);
 };
 
@@ -108,13 +104,13 @@ MakeError(Error, BaseError)
   std::string addErrno(const std::string& s);
 };
 
-typedef list<string> Strings;
-typedef set<string> StringSet;
+typedef std::list<std::string> Strings;
+typedef std::set<std::string> StringSet;
 typedef std::map<std::string, std::string> StringMap;
 
 /* Paths are just strings. */
-typedef string Path;
-typedef list<Path> Paths;
-typedef set<Path> PathSet;
+typedef std::string Path;
+typedef std::list<Path> Paths;
+typedef std::set<Path> PathSet;
 
 }  // namespace nix
diff --git a/third_party/nix/src/libutil/util.cc b/third_party/nix/src/libutil/util.cc
index 53d037cf5801..696a8ff2365e 100644
--- a/third_party/nix/src/libutil/util.cc
+++ b/third_party/nix/src/libutil/util.cc
@@ -42,9 +42,9 @@ std::string SysError::addErrno(const std::string& s) {
   return s + ": " + strerror(errNo);
 }
 
-string getEnv(const string& key, const string& def) {
+std::string getEnv(const std::string& key, const std::string& def) {
   char* value = getenv(key.c_str());
-  return value != nullptr ? string(value) : def;
+  return value != nullptr ? std::string(value) : def;
 }
 
 std::map<std::string, std::string> getEnv() {
@@ -101,15 +101,15 @@ return canonPath(path);
 Path canonPath(const Path& path, bool resolveSymlinks) {
   assert(!path.empty());
 
-  string s;
+  std::string s;
 
   if (path[0] != '/') {
     throw Error(format("not an absolute path: '%1%'") % path);
   }
 
-  string::const_iterator i = path.begin();
-  string::const_iterator end = path.end();
-  string temp;
+  std::string::const_iterator i = path.begin();
+  std::string::const_iterator end = path.end();
+  std::string temp;
 
   /* Count the number of times we follow a symlink and stop at some
      arbitrary (but high) limit to prevent infinite loops. */
@@ -153,7 +153,7 @@ Path canonPath(const Path& path, bool resolveSymlinks) {
           throw Error(format("infinite symlink recursion in path '%1%'") %
                       path);
         }
-        temp = absPath(readLink(s), dirOf(s)) + string(i, end);
+        temp = absPath(readLink(s), dirOf(s)) + std::string(i, end);
         i = temp.begin(); /* restart */
         end = temp.end();
         s = "";
@@ -166,13 +166,13 @@ Path canonPath(const Path& path, bool resolveSymlinks) {
 
 Path dirOf(const Path& path) {
   Path::size_type pos = path.rfind('/');
-  if (pos == string::npos) {
+  if (pos == std::string::npos) {
     return ".";
   }
   return pos == 0 ? "/" : Path(path, 0, pos);
 }
 
-string baseNameOf(const Path& path) {
+std::string baseNameOf(const Path& path) {
   if (path.empty()) {
     return "";
   }
@@ -183,17 +183,17 @@ string baseNameOf(const Path& path) {
   }
 
   Path::size_type pos = path.rfind('/', last);
-  if (pos == string::npos) {
+  if (pos == std::string::npos) {
     pos = 0;
   } else {
     pos += 1;
   }
 
-  return string(path, pos, last - pos + 1);
+  return std::string(path, pos, last - pos + 1);
 }
 
 bool isInDir(const Path& path, const Path& dir) {
-  return path[0] == '/' && string(path, 0, dir.size()) == dir &&
+  return path[0] == '/' && std::string(path, 0, dir.size()) == dir &&
          path.size() >= dir.size() + 2 && path[dir.size()] == '/';
 }
 
@@ -235,7 +235,7 @@ Path readLink(const Path& path) {
       throw SysError("reading symbolic link '%1%'", path);
 
     } else if (rlSize < bufSize) {
-      return string(buf.data(), rlSize);
+      return std::string(buf.data(), rlSize);
     }
   }
 }
@@ -252,7 +252,7 @@ DirEntries readDirectory(DIR* dir, const Path& path) {
   struct dirent* dirent;
   while (errno = 0, dirent = readdir(dir)) { /* sic */
     checkInterrupt();
-    string name = dirent->d_name;
+    std::string name = dirent->d_name;
     if (name == "." || name == "..") {
       continue;
     }
@@ -294,7 +294,7 @@ unsigned char getFileType(const Path& path) {
   return DT_UNKNOWN;
 }
 
-string readFile(int fd) {
+std::string readFile(int fd) {
   struct stat st;
   if (fstat(fd, &st) == -1) {
     throw SysError("statting file");
@@ -303,10 +303,10 @@ string readFile(int fd) {
   std::vector<unsigned char> buf(st.st_size);
   readFull(fd, buf.data(), st.st_size);
 
-  return string((char*)buf.data(), st.st_size);
+  return std::string((char*)buf.data(), st.st_size);
 }
 
-string readFile(const Path& path, bool drain) {
+std::string readFile(const Path& path, bool drain) {
   AutoCloseFD fd = open(path.c_str(), O_RDONLY | O_CLOEXEC);
   if (!fd) {
     throw SysError(format("opening file '%1%'") % path);
@@ -322,7 +322,7 @@ void readFile(const Path& path, Sink& sink) {
   drainFD(fd.get(), sink);
 }
 
-void writeFile(const Path& path, const string& s, mode_t mode) {
+void writeFile(const Path& path, const std::string& s, mode_t mode) {
   AutoCloseFD fd =
       open(path.c_str(), O_WRONLY | O_TRUNC | O_CREAT | O_CLOEXEC, mode);
   if (!fd) {
@@ -350,8 +350,8 @@ void writeFile(const Path& path, Source& source, mode_t mode) {
   }
 }
 
-string readLine(int fd) {
-  string s;
+std::string readLine(int fd) {
+  std::string s;
   while (true) {
     checkInterrupt();
     char ch;
@@ -372,7 +372,7 @@ string readLine(int fd) {
   }
 }
 
-void writeLine(int fd, string s) {
+void writeLine(int fd, std::string s) {
   s += '\n';
   writeFull(fd, s);
 }
@@ -381,7 +381,7 @@ static void _deletePath(int parentfd, const Path& path,
                         unsigned long long& bytesFreed) {
   checkInterrupt();
 
-  string name(baseNameOf(path));
+  std::string name(baseNameOf(path));
 
   struct stat st;
   if (fstatat(parentfd, name.c_str(), &st, AT_SYMLINK_NOFOLLOW) == -1) {
@@ -539,8 +539,8 @@ Path getConfigDir() {
 
 std::vector<Path> getConfigDirs() {
   Path configHome = getConfigDir();
-  string configDirs = getEnv("XDG_CONFIG_DIRS");
-  auto result = tokenizeString<std::vector<string>>(configDirs, ":");
+  std::string configDirs = getEnv("XDG_CONFIG_DIRS");
+  auto result = tokenizeString<std::vector<std::string>>(configDirs, ":");
   result.insert(result.begin(), configHome);
   return result;
 }
@@ -643,11 +643,11 @@ void writeFull(int fd, const unsigned char* buf, size_t count,
   }
 }
 
-void writeFull(int fd, const string& s, bool allowInterrupts) {
+void writeFull(int fd, const std::string& s, bool allowInterrupts) {
   writeFull(fd, (const unsigned char*)s.data(), s.size(), allowInterrupts);
 }
 
-string drainFD(int fd, bool block) {
+std::string drainFD(int fd, bool block) {
   StringSink sink;
   drainFD(fd, sink, block);
   return std::move(*sink.s);
@@ -694,7 +694,7 @@ void drainFD(int fd, Sink& sink, bool block) {
 
 AutoDelete::AutoDelete() : del{false} {}
 
-AutoDelete::AutoDelete(string p, bool recursive) : path(std::move(p)) {
+AutoDelete::AutoDelete(std::string p, bool recursive) : path(std::move(p)) {
   del = true;
   this->recursive = recursive;
 }
@@ -812,7 +812,7 @@ int Pid::kill() {
      process group, send the signal to every process in the child
      process group (which hopefully includes *all* its children). */
   if (::kill(separatePG ? -pid : pid, killSignal) != 0) {
-      LOG(ERROR) << SysError("killing process %d", pid).msg();
+    LOG(ERROR) << SysError("killing process %d", pid).msg();
   }
 
   return wait();
@@ -950,8 +950,9 @@ std::vector<char*> stringsToCharPtrs(const Strings& ss) {
   return res;
 }
 
-string runProgram(const Path& program, bool searchPath, const Strings& args,
-                  const std::optional<std::string>& input) {
+std::string runProgram(const Path& program, bool searchPath,
+                       const Strings& args,
+                       const std::optional<std::string>& input) {
   RunOptions opts(program, args);
   opts.searchPath = searchPath;
   opts.input = input;
@@ -1114,7 +1115,7 @@ void runProgram2(const RunOptions& options) {
   }
 }
 
-void closeMostFDs(const set<int>& exceptions) {
+void closeMostFDs(const std::set<int>& exceptions) {
 #if __linux__
   try {
     for (auto& s : readDirectory("/proc/self/fd")) {
@@ -1168,28 +1169,30 @@ void _interrupted() {
 //////////////////////////////////////////////////////////////////////
 
 template <class C>
-C tokenizeString(const string& s, const string& separators) {
+C tokenizeString(const std::string& s, const std::string& separators) {
   C result;
-  string::size_type pos = s.find_first_not_of(separators, 0);
-  while (pos != string::npos) {
-    string::size_type end = s.find_first_of(separators, pos + 1);
-    if (end == string::npos) {
+  std::string::size_type pos = s.find_first_not_of(separators, 0);
+  while (pos != std::string::npos) {
+    std::string::size_type end = s.find_first_of(separators, pos + 1);
+    if (end == std::string::npos) {
       end = s.size();
     }
-    string token(s, pos, end - pos);
+    std::string token(s, pos, end - pos);
     result.insert(result.end(), token);
     pos = s.find_first_not_of(separators, end);
   }
   return result;
 }
 
-template Strings tokenizeString(const string& s, const string& separators);
-template StringSet tokenizeString(const string& s, const string& separators);
-template vector<string> tokenizeString(const string& s,
-                                       const string& separators);
+template Strings tokenizeString(const std::string& s,
+                                const std::string& separators);
+template StringSet tokenizeString(const std::string& s,
+                                  const std::string& separators);
+template std::vector<std::string> tokenizeString(const std::string& s,
+                                                 const std::string& separators);
 
-string concatStringsSep(const string& sep, const Strings& ss) {
-  string s;
+std::string concatStringsSep(const std::string& sep, const Strings& ss) {
+  std::string s;
   for (auto& i : ss) {
     if (!s.empty()) {
       s += sep;
@@ -1199,8 +1202,8 @@ string concatStringsSep(const string& sep, const Strings& ss) {
   return s;
 }
 
-string concatStringsSep(const string& sep, const StringSet& ss) {
-  string s;
+std::string concatStringsSep(const std::string& sep, const StringSet& ss) {
+  std::string s;
   for (auto& i : ss) {
     if (!s.empty()) {
       s += sep;
@@ -1210,21 +1213,21 @@ string concatStringsSep(const string& sep, const StringSet& ss) {
   return s;
 }
 
-string trim(const string& s, const string& whitespace) {
+std::string trim(const std::string& s, const std::string& whitespace) {
   auto i = s.find_first_not_of(whitespace);
-  if (i == string::npos) {
+  if (i == std::string::npos) {
     return "";
   }
   auto j = s.find_last_not_of(whitespace);
-  return string(s, i, j == string::npos ? j : j - i + 1);
+  return std::string(s, i, j == std::string::npos ? j : j - i + 1);
 }
 
-string replaceStrings(const std::string& s, const std::string& from,
-                      const std::string& to) {
+std::string replaceStrings(const std::string& s, const std::string& from,
+                           const std::string& to) {
   if (from.empty()) {
     return s;
   }
-  string res = s;
+  std::string res = s;
   size_t pos = 0;
   while ((pos = res.find(from, pos)) != std::string::npos) {
     res.replace(pos, from.size(), to);
@@ -1233,7 +1236,7 @@ string replaceStrings(const std::string& s, const std::string& from,
   return res;
 }
 
-string statusToString(int status) {
+std::string statusToString(int status) {
   if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
     if (WIFEXITED(status)) {
       return (format("failed with exit code %1%") % WEXITSTATUS(status)).str();
@@ -1259,13 +1262,13 @@ bool statusOk(int status) {
   return WIFEXITED(status) && WEXITSTATUS(status) == 0;
 }
 
-bool hasPrefix(const string& s, const string& prefix) {
+bool hasPrefix(const std::string& s, const std::string& prefix) {
   return s.compare(0, prefix.size(), prefix) == 0;
 }
 
-bool hasSuffix(const string& s, const string& suffix) {
+bool hasSuffix(const std::string& s, const std::string& suffix) {
   return s.size() >= suffix.size() &&
-         string(s, s.size() - suffix.size()) == suffix;
+         std::string(s, s.size() - suffix.size()) == suffix;
 }
 
 std::string toLower(const std::string& s) {
@@ -1361,8 +1364,8 @@ std::string filterANSIEscapes(const std::string& s, bool filterAll,
 static char base64Chars[] =
     "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 
-string base64Encode(const string& s) {
-  string res;
+std::string base64Encode(const std::string& s) {
+  std::string res;
   int data = 0;
   int nbits = 0;
 
@@ -1385,7 +1388,7 @@ string base64Encode(const string& s) {
   return res;
 }
 
-string base64Decode(const string& s) {
+std::string base64Decode(const std::string& s) {
   bool init = false;
   char decode[256];
   if (!init) {
@@ -1397,7 +1400,7 @@ string base64Decode(const string& s) {
     init = true;
   }
 
-  string res;
+  std::string res;
   unsigned int d = 0;
   unsigned int bits = 0;
 
diff --git a/third_party/nix/src/libutil/util.hh b/third_party/nix/src/libutil/util.hh
index 3c8d4bd70c06..7d10df50bf5b 100644
--- a/third_party/nix/src/libutil/util.hh
+++ b/third_party/nix/src/libutil/util.hh
@@ -32,7 +32,7 @@ struct Source;
 extern const std::string nativeSystem;
 
 /* Return an environment variable. */
-string getEnv(const string& key, const string& def = "");
+std::string getEnv(const std::string& key, const std::string& def = "");
 
 /* Get the entire environment. */
 std::map<std::string, std::string> getEnv();
@@ -59,7 +59,7 @@ Path dirOf(const Path& path);
 
 /* Return the base name of the given canonical path, i.e., everything
    following the final `/'. */
-string baseNameOf(const Path& path);
+std::string baseNameOf(const Path& path);
 
 /* Check whether 'path' is a descendant of 'dir'. */
 bool isInDir(const Path& path, const Path& dir);
@@ -82,34 +82,34 @@ bool isLink(const Path& path);
 /* Read the contents of a directory.  The entries `.' and `..' are
    removed. */
 struct DirEntry {
-  string name;
+  std::string name;
   ino_t ino;
   unsigned char type;  // one of DT_*
-  DirEntry(const string& name, ino_t ino, unsigned char type)
+  DirEntry(const std::string& name, ino_t ino, unsigned char type)
       : name(name), ino(ino), type(type) {}
 };
 
-typedef vector<DirEntry> DirEntries;
+typedef std::vector<DirEntry> DirEntries;
 
 DirEntries readDirectory(const Path& path);
 
 unsigned char getFileType(const Path& path);
 
 /* Read the contents of a file into a string. */
-string readFile(int fd);
-string readFile(const Path& path, bool drain = false);
+std::string readFile(int fd);
+std::string readFile(const Path& path, bool drain = false);
 void readFile(const Path& path, Sink& sink);
 
 /* Write a string to a file. */
-void writeFile(const Path& path, const string& s, mode_t mode = 0666);
+void writeFile(const Path& path, const std::string& s, mode_t mode = 0666);
 
 void writeFile(const Path& path, Source& source, mode_t mode = 0666);
 
 /* Read a line from a file descriptor. */
-string readLine(int fd);
+std::string readLine(int fd);
 
 /* Write a line to a file descriptor. */
-void writeLine(int fd, string s);
+void writeLine(int fd, std::string s);
 
 /* Delete a path; i.e., in the case of a directory, it is deleted
    recursively. It's not an error if the path does not exist. The
@@ -155,12 +155,12 @@ void replaceSymlink(const Path& target, const Path& link);
 void readFull(int fd, unsigned char* buf, size_t count);
 void writeFull(int fd, const unsigned char* buf, size_t count,
                bool allowInterrupts = true);
-void writeFull(int fd, const string& s, bool allowInterrupts = true);
+void writeFull(int fd, const std::string& s, bool allowInterrupts = true);
 
-MakeError(EndOfFile, Error)
+MakeError(EndOfFile, Error);
 
-    /* Read a file descriptor until EOF occurs. */
-    string drainFD(int fd, bool block = true);
+/* Read a file descriptor until EOF occurs. */
+std::string drainFD(int fd, bool block = true);
 
 void drainFD(int fd, Sink& sink, bool block = true);
 
@@ -235,7 +235,7 @@ void killUser(uid_t uid);
 /* Fork a process that runs the given function, and return the child
    pid to the caller. */
 struct ProcessOptions {
-  string errorPrefix = "error: ";
+  std::string errorPrefix = "error: ";
   bool dieWithParent = true;
   bool runExitHandlers = false;
   bool allowVfork = true;
@@ -246,9 +246,9 @@ pid_t startProcess(std::function<void()> fun,
 
 /* Run a program and return its stdout in a string (i.e., like the
    shell backtick operator). */
-string runProgram(const Path& program, bool searchPath = false,
-                  const Strings& args = Strings(),
-                  const std::optional<std::string>& input = {});
+std::string runProgram(const Path& program, bool searchPath = false,
+                       const Strings& args = Strings(),
+                       const std::optional<std::string>& input = {});
 
 struct RunOptions {
   std::optional<uid_t> uid;
@@ -292,7 +292,7 @@ std::vector<char*> stringsToCharPtrs(const Strings& ss);
 
 /* Close all file descriptors except those listed in the given set.
    Good practice in child processes. */
-void closeMostFDs(const set<int>& exceptions);
+void closeMostFDs(const std::set<int>& exceptions);
 
 /* Set the close-on-exec flag for the given file descriptor. */
 void closeOnExec(int fd);
@@ -311,36 +311,38 @@ void inline checkInterrupt() {
   if (_isInterrupted || (interruptCheck && interruptCheck())) _interrupted();
 }
 
-MakeError(Interrupted, BaseError)
+MakeError(Interrupted, BaseError);
 
-    MakeError(FormatError, Error)
+MakeError(FormatError, Error);
 
-    /* String tokenizer. */
-    template <class C>
-    C tokenizeString(const string& s, const string& separators = " \t\n\r");
+/* String tokenizer. */
+template <class C>
+C tokenizeString(const std::string& s,
+                 const std::string& separators = " \t\n\r");
 
 /* Concatenate the given strings with a separator between the
    elements. */
-string concatStringsSep(const string& sep, const Strings& ss);
-string concatStringsSep(const string& sep, const StringSet& ss);
+std::string concatStringsSep(const std::string& sep, const Strings& ss);
+std::string concatStringsSep(const std::string& sep, const StringSet& ss);
 
 /* Remove whitespace from the start and end of a string. */
-string trim(const string& s, const string& whitespace = " \n\r\t");
+std::string trim(const std::string& s,
+                 const std::string& whitespace = " \n\r\t");
 
 /* Replace all occurrences of a string inside another string. */
-string replaceStrings(const std::string& s, const std::string& from,
-                      const std::string& to);
+std::string replaceStrings(const std::string& s, const std::string& from,
+                           const std::string& to);
 
 /* Convert the exit status of a child as returned by wait() into an
    error string. */
-string statusToString(int status);
+std::string statusToString(int status);
 
 bool statusOk(int status);
 
 /* Parse a string into an integer. */
 template <class N>
-bool string2Int(const string& s, N& n) {
-  if (string(s, 0, 1) == "-" && !std::numeric_limits<N>::is_signed)
+bool string2Int(const std::string& s, N& n) {
+  if (std::string(s, 0, 1) == "-" && !std::numeric_limits<N>::is_signed)
     return false;
   std::istringstream str(s);
   str >> n;
@@ -349,17 +351,17 @@ bool string2Int(const string& s, N& n) {
 
 /* Parse a string into a float. */
 template <class N>
-bool string2Float(const string& s, N& n) {
+bool string2Float(const std::string& s, N& n) {
   std::istringstream str(s);
   str >> n;
   return str && str.get() == EOF;
 }
 
 /* Return true iff `s' starts with `prefix'. */
-bool hasPrefix(const string& s, const string& prefix);
+bool hasPrefix(const std::string& s, const std::string& prefix);
 
 /* Return true iff `s' ends in `suffix'. */
-bool hasSuffix(const string& s, const string& suffix);
+bool hasSuffix(const std::string& s, const std::string& suffix);
 
 /* Convert a string to lower case. */
 std::string toLower(const std::string& s);
@@ -389,13 +391,14 @@ std::string filterANSIEscapes(
     unsigned int width = std::numeric_limits<unsigned int>::max());
 
 /* Base64 encoding/decoding. */
-string base64Encode(const string& s);
-string base64Decode(const string& s);
+std::string base64Encode(const std::string& s);
+std::string base64Decode(const std::string& s);
 
 /* Get a value for the specified key from an associate container, or a
    default value if the key doesn't exist. */
 template <class T>
-string get(const T& map, const string& key, const string& def = "") {
+std::string get(const T& map, const std::string& key,
+                const std::string& def = "") {
   auto i = map.find(key);
   return i == map.end() ? def : i->second;
 }
diff --git a/third_party/nix/src/libutil/xml-writer.cc b/third_party/nix/src/libutil/xml-writer.cc
index 11cd632399ad..d34e9a2f0d59 100644
--- a/third_party/nix/src/libutil/xml-writer.cc
+++ b/third_party/nix/src/libutil/xml-writer.cc
@@ -26,10 +26,10 @@ void XMLWriter::indent_(size_t depth) {
   if (!indent) {
     return;
   }
-  output << string(depth * 2, ' ');
+  output << std::string(depth * 2, ' ');
 }
 
-void XMLWriter::openElement(const string& name, const XMLAttrs& attrs) {
+void XMLWriter::openElement(const std::string& name, const XMLAttrs& attrs) {
   assert(!closed);
   indent_(pendingElems.size());
   output << "<" << name;
@@ -54,7 +54,8 @@ void XMLWriter::closeElement() {
   }
 }
 
-void XMLWriter::writeEmptyElement(const string& name, const XMLAttrs& attrs) {
+void XMLWriter::writeEmptyElement(const std::string& name,
+                                  const XMLAttrs& attrs) {
   assert(!closed);
   indent_(pendingElems.size());
   output << "<" << name;
diff --git a/third_party/nix/src/libutil/xml-writer.hh b/third_party/nix/src/libutil/xml-writer.hh
index 3a2d9a66d8e1..76f3c7e3a2f4 100644
--- a/third_party/nix/src/libutil/xml-writer.hh
+++ b/third_party/nix/src/libutil/xml-writer.hh
@@ -11,7 +11,7 @@ using std::list;
 using std::map;
 using std::string;
 
-typedef map<string, string> XMLAttrs;
+typedef map<std::string, std::string> XMLAttrs;
 
 class XMLWriter {
  private:
@@ -20,7 +20,7 @@ class XMLWriter {
   bool indent;
   bool closed;
 
-  list<string> pendingElems;
+  std::list<std::string> pendingElems;
 
  public:
   XMLWriter(bool indent, std::ostream& output);
@@ -28,10 +28,10 @@ class XMLWriter {
 
   void close();
 
-  void openElement(const string& name, const XMLAttrs& attrs = XMLAttrs());
+  void openElement(const std::string& name, const XMLAttrs& attrs = XMLAttrs());
   void closeElement();
 
-  void writeEmptyElement(const string& name,
+  void writeEmptyElement(const std::string& name,
                          const XMLAttrs& attrs = XMLAttrs());
 
  private:
@@ -45,7 +45,7 @@ class XMLOpenElement {
   XMLWriter& writer;
 
  public:
-  XMLOpenElement(XMLWriter& writer, const string& name,
+  XMLOpenElement(XMLWriter& writer, const std::string& name,
                  const XMLAttrs& attrs = XMLAttrs())
       : writer(writer) {
     writer.openElement(name, attrs);
diff --git a/third_party/nix/src/nix-build/nix-build.cc b/third_party/nix/src/nix-build/nix-build.cc
index a98603f35109..6906a805830e 100644
--- a/third_party/nix/src/nix-build/nix-build.cc
+++ b/third_party/nix/src/nix-build/nix-build.cc
@@ -27,10 +27,10 @@ using namespace std::string_literals;
 /* Recreate the effect of the perl shellwords function, breaking up a
  * string into arguments like a shell word, including escapes
  */
-std::vector<string> shellwords(const string& s) {
+std::vector<std::string> shellwords(const std::string& s) {
   std::regex whitespace("^(\\s+).*");
   auto begin = s.cbegin();
-  std::vector<string> res;
+  std::vector<std::string> res;
   std::string cur;
   enum state { sBegin, sQuote };
   state st = sBegin;
@@ -90,14 +90,14 @@ static void _main(int argc, char** argv) {
 
   auto inShebang = false;
   std::string script;
-  std::vector<string> savedArgs;
+  std::vector<std::string> savedArgs;
 
   AutoDelete tmpDir(createTempDir("", myName));
 
   std::string outLink = "./result";
 
   // List of environment variables kept for --pure
-  std::set<string> keepVars{
+  std::set<std::string> keepVars{
       "HOME",         "USER", "LOGNAME", "DISPLAY",         "PATH", "TERM",
       "IN_NIX_SHELL", "TZ",   "PAGER",   "NIX_BUILD_SHELL", "SHLVL"};
 
@@ -405,7 +405,7 @@ static void _main(int argc, char** argv) {
     // Build or fetch all dependencies of the derivation.
     for (const auto& input : drv.inputDrvs) {
       if (std::all_of(envExclude.cbegin(), envExclude.cend(),
-                      [&](const string& exclude) {
+                      [&](const std::string& exclude) {
                         return !std::regex_search(input.first,
                                                   std::regex(exclude));
                       })) {
@@ -452,7 +452,7 @@ static void _main(int argc, char** argv) {
     for (auto& var : drv.env) {
       if (passAsFile.count(var.first) != 0u) {
         keepTmp = true;
-        string fn = ".attr-" + std::to_string(fileNr++);
+        std::string fn = ".attr-" + std::to_string(fileNr++);
         Path p = (Path)tmpDir + "/" + fn;
         writeFile(p, var.second);
         env[var.first + "Path"] = p;
@@ -489,7 +489,7 @@ static void _main(int argc, char** argv) {
             (Path)tmpDir, (pure ? "" : "p=$PATH; "),
             (pure ? "" : "PATH=$PATH:$p; unset p; "), dirOf(shell), shell,
             (getenv("TZ") != nullptr
-                 ? (string("export TZ='") + getenv("TZ") + "'; ")
+                 ? (std::string("export TZ='") + getenv("TZ") + "'; ")
                  : ""),
             envCommand));
 
diff --git a/third_party/nix/src/nix-channel/nix-channel.cc b/third_party/nix/src/nix-channel/nix-channel.cc
index 1a094f8cdb35..04a492d80a03 100644
--- a/third_party/nix/src/nix-channel/nix-channel.cc
+++ b/third_party/nix/src/nix-channel/nix-channel.cc
@@ -12,7 +12,7 @@
 
 using namespace nix;
 
-typedef std::map<string, string> Channels;
+typedef std::map<std::string, std::string> Channels;
 
 static Channels channels;
 static Path channelsList;
@@ -25,12 +25,12 @@ static void readChannels() {
   auto channelsFile = readFile(channelsList);
 
   for (const auto& line :
-       tokenizeString<std::vector<string>>(channelsFile, "\n")) {
+       tokenizeString<std::vector<std::string>>(channelsFile, "\n")) {
     absl::StripTrailingAsciiWhitespace(line);
     if (std::regex_search(line, std::regex("^\\s*\\#"))) {
       continue;
     }
-    auto split = tokenizeString<std::vector<string>>(line, " ");
+    auto split = tokenizeString<std::vector<std::string>>(line, " ");
     auto url = std::regex_replace(split[0], std::regex("/*$"), "");
     auto name = split.size() > 1 ? split[1] : baseNameOf(url);
     channels[name] = url;
@@ -50,7 +50,7 @@ static void writeChannels() {
 }
 
 // Adds a channel.
-static void addChannel(const string& url, const string& name) {
+static void addChannel(const std::string& url, const std::string& name) {
   if (!regex_search(url, std::regex("^(file|http|https)://"))) {
     throw Error(format("invalid channel URL '%1%'") % url);
   }
@@ -65,7 +65,7 @@ static void addChannel(const string& url, const string& name) {
 static Path profile;
 
 // Remove a channel.
-static void removeChannel(const string& name) {
+static void removeChannel(const std::string& name) {
   readChannels();
   channels.erase(name);
   writeChannels();
@@ -109,7 +109,7 @@ static void update(const StringSet& channelNames) {
     std::smatch match;
     auto urlBase = baseNameOf(url);
     if (std::regex_search(urlBase, match, std::regex("(-\\d.*)$"))) {
-      cname = cname + (string)match[1];
+      cname = cname + (std::string)match[1];
     }
 
     std::string extraAttrs;
@@ -188,7 +188,7 @@ static int _main(int argc, char** argv) {
                   getUserName());
 
     enum { cNone, cAdd, cRemove, cList, cUpdate, cRollback } cmd = cNone;
-    std::vector<string> args;
+    std::vector<std::string> args;
     parseCmdLine(argc, argv,
                  [&](Strings::iterator& arg, const Strings::iterator& end) {
                    if (*arg == "--help") {
diff --git a/third_party/nix/src/nix-collect-garbage/nix-collect-garbage.cc b/third_party/nix/src/nix-collect-garbage/nix-collect-garbage.cc
index 0050bdda15fb..548e492664de 100644
--- a/third_party/nix/src/nix-collect-garbage/nix-collect-garbage.cc
+++ b/third_party/nix/src/nix-collect-garbage/nix-collect-garbage.cc
@@ -40,7 +40,7 @@ void removeOldGenerations(const std::string& dir) {
           continue;
         }
       }
-      if (link.find("link") != string::npos) {
+      if (link.find("link") != std::string::npos) {
         LOG(INFO) << "removing old generations of profile " << path;
         if (!deleteOlderThan.empty()) {
           deleteGenerationsOlderThan(path, deleteOlderThan, dryRun);
diff --git a/third_party/nix/src/nix-daemon/nix-daemon.cc b/third_party/nix/src/nix-daemon/nix-daemon.cc
index 5a38e023fa9b..5b62d67dbe1c 100644
--- a/third_party/nix/src/nix-daemon/nix-daemon.cc
+++ b/third_party/nix/src/nix-daemon/nix-daemon.cc
@@ -115,7 +115,7 @@ struct TunnelLogger {
 
   /* stopWork() means that we're done; stop sending stderr to the
      client. */
-  void stopWork(bool success = true, const string& msg = "",
+  void stopWork(bool success = true, const std::string& msg = "",
                 unsigned int status = 0) {
     auto state(state_.lock());
 
@@ -175,7 +175,7 @@ struct TunnelSource : BufferedSource {
    the contents of the file to `s'.  Otherwise barf. */
 struct RetrieveRegularNARSink : ParseSink {
   bool regular{true};
-  string s;
+  std::string s;
 
   RetrieveRegularNARSink() {}
 
@@ -185,7 +185,7 @@ struct RetrieveRegularNARSink : ParseSink {
     s.append((const char*)data, len);
   }
 
-  void createSymlink(const Path& path, const string& target) override {
+  void createSymlink(const Path& path, const std::string& target) override {
     regular = false;
   }
 };
@@ -286,7 +286,7 @@ static void performOp(TunnelLogger* logger, const ref<Store>& store,
     }
 
     case wopQueryPathFromHashPart: {
-      string hashPart = readString(from);
+      std::string hashPart = readString(from);
       logger->startWork();
       Path path = store->queryPathFromHashPart(hashPart);
       logger->stopWork();
@@ -340,8 +340,8 @@ static void performOp(TunnelLogger* logger, const ref<Store>& store,
     }
 
     case wopAddTextToStore: {
-      string suffix = readString(from);
-      string s = readString(from);
+      std::string suffix = readString(from);
+      std::string s = readString(from);
       auto refs = readStorePaths<PathSet>(*store, from);
       logger->startWork();
       Path path = store->addTextToStore(suffix, s, refs, NoRepair);
@@ -505,8 +505,8 @@ static void performOp(TunnelLogger* logger, const ref<Store>& store,
       if (GET_PROTOCOL_MINOR(clientVersion) >= 12) {
         unsigned int n = readInt(from);
         for (unsigned int i = 0; i < n; i++) {
-          string name = readString(from);
-          string value = readString(from);
+          std::string name = readString(from);
+          std::string value = readString(from);
           overrides.emplace(name, value);
         }
       }
@@ -855,7 +855,8 @@ static void setSigChldAction(bool autoReap) {
   }
 }
 
-bool matchUser(const string& user, const string& group, const Strings& users) {
+bool matchUser(const std::string& user, const std::string& group,
+               const Strings& users) {
   if (find(users.begin(), users.end(), "*") != users.end()) {
     return true;
   }
@@ -865,8 +866,8 @@ bool matchUser(const string& user, const string& group, const Strings& users) {
   }
 
   for (auto& i : users) {
-    if (string(i, 0, 1) == "@") {
-      if (group == string(i, 1)) {
+    if (std::string(i, 0, 1) == "@") {
+      if (group == std::string(i, 1)) {
         return true;
       }
       struct group* gr = getgrnam(i.c_str() + 1);
@@ -874,7 +875,7 @@ bool matchUser(const string& user, const string& group, const Strings& users) {
         continue;
       }
       for (char** mem = gr->gr_mem; *mem != nullptr; mem++) {
-        if (user == string(*mem)) {
+        if (user == std::string(*mem)) {
           return true;
         }
       }
@@ -953,7 +954,7 @@ static void daemonLoop(char** argv) {
       throw SysError("cannot create Unix domain socket");
     }
 
-    string socketPath = settings.nixDaemonSocketFile;
+    std::string socketPath = settings.nixDaemonSocketFile;
 
     createDirs(dirOf(socketPath));
 
@@ -1018,10 +1019,11 @@ static void daemonLoop(char** argv) {
       PeerInfo peer = getPeerInfo(remote.get());
 
       struct passwd* pw = peer.uidKnown ? getpwuid(peer.uid) : nullptr;
-      string user = pw != nullptr ? pw->pw_name : std::to_string(peer.uid);
+      std::string user = pw != nullptr ? pw->pw_name : std::to_string(peer.uid);
 
       struct group* gr = peer.gidKnown ? getgrgid(peer.gid) : nullptr;
-      string group = gr != nullptr ? gr->gr_name : std::to_string(peer.gid);
+      std::string group =
+          gr != nullptr ? gr->gr_name : std::to_string(peer.gid);
 
       Strings trustedUsers = settings.trustedUsers;
       Strings allowedUsers = settings.allowedUsers;
@@ -1062,7 +1064,7 @@ static void daemonLoop(char** argv) {
 
             /* For debugging, stuff the pid into argv[1]. */
             if (peer.pidKnown && (argv[1] != nullptr)) {
-              string processName = std::to_string(peer.pid);
+              std::string processName = std::to_string(peer.pid);
               strncpy(argv[1], processName.c_str(), strlen(argv[1]));
             }
 
diff --git a/third_party/nix/src/nix-env/nix-env.cc b/third_party/nix/src/nix-env/nix-env.cc
index e5b76979245d..794250e603b1 100644
--- a/third_party/nix/src/nix-env/nix-env.cc
+++ b/third_party/nix/src/nix-env/nix-env.cc
@@ -40,9 +40,9 @@ typedef enum {
 
 struct InstallSourceInfo {
   InstallSourceType type;
-  Path nixExprPath;    /* for srcNixExprDrvs, srcNixExprs */
-  Path profile;        /* for srcProfile */
-  string systemFilter; /* for srcNixExprDrvs */
+  Path nixExprPath;         /* for srcNixExprDrvs, srcNixExprs */
+  Path profile;             /* for srcProfile */
+  std::string systemFilter; /* for srcNixExprDrvs */
   Bindings* autoArgs;
 };
 
@@ -53,13 +53,14 @@ struct Globals {
   bool dryRun;
   bool preserveInstalled;
   bool removeAll;
-  string forceName;
+  std::string forceName;
   bool prebuiltOnly;
 };
 
 using Operation = void (*)(Globals&, Strings, Strings);
 
-static string needArg(Strings::iterator& i, Strings& args, const string& arg) {
+static std::string needArg(Strings::iterator& i, Strings& args,
+                           const std::string& arg) {
   if (i == args.end()) {
     throw UsageError(format("'%1%' requires an argument") % arg);
   }
@@ -67,7 +68,7 @@ static string needArg(Strings::iterator& i, Strings& args, const string& arg) {
 }
 
 static bool parseInstallSourceOptions(Globals& globals, Strings::iterator& i,
-                                      Strings& args, const string& arg) {
+                                      Strings& args, const std::string& arg) {
   if (arg == "--from-expression" || arg == "-E") {
     globals.instSource.type = srcNixExprs;
   } else if (arg == "--from-profile") {
@@ -114,9 +115,9 @@ static void getAllExprs(EvalState& state, const Path& path, StringSet& attrs,
          otherwise the attribute cannot be selected with the
          `-A' option.  Useful if you want to stick a Nix
          expression directly in ~/.nix-defexpr. */
-      string attrName = i;
+      std::string attrName = i;
       if (hasSuffix(attrName, ".nix")) {
-        attrName = string(attrName, 0, attrName.size() - 4);
+        attrName = std::string(attrName, 0, attrName.size() - 4);
       }
       if (attrs.find(attrName) != attrs.end()) {
         LOG(WARNING) << "name collision in input Nix expressions, skipping '"
@@ -167,8 +168,8 @@ static void loadSourceExpr(EvalState& state, const Path& path, Value& v) {
 }
 
 static void loadDerivations(EvalState& state, const Path& nixExprPath,
-                            const string& systemFilter, Bindings& autoArgs,
-                            const string& pathPrefix, DrvInfos& elems) {
+                            const std::string& systemFilter, Bindings& autoArgs,
+                            const std::string& pathPrefix, DrvInfos& elems) {
   Value vRoot;
   loadSourceExpr(state, nixExprPath, vRoot);
 
@@ -223,10 +224,10 @@ static DrvInfos filterBySelector(EvalState& state, const DrvInfos& allElems,
   }
 
   DrvInfos elems;
-  set<unsigned int> done;
+  std::set<unsigned int> done;
 
   for (auto& i : selectors) {
-    typedef list<std::pair<DrvInfo, unsigned int> > Matches;
+    typedef std::list<std::pair<DrvInfo, unsigned int> > Matches;
     Matches matches;
     unsigned int n = 0;
     for (auto j = allElems.begin(); j != allElems.end(); ++j, ++n) {
@@ -246,7 +247,7 @@ static DrvInfos filterBySelector(EvalState& state, const DrvInfos& allElems,
        arbitrarily pick the first one. */
     if (newestOnly) {
       /* Map from package names to derivations. */
-      typedef map<string, std::pair<DrvInfo, unsigned int> > Newest;
+      typedef map<std::string, std::pair<DrvInfo, unsigned int> > Newest;
       Newest newest;
       StringSet multiple;
 
@@ -308,7 +309,9 @@ static DrvInfos filterBySelector(EvalState& state, const DrvInfos& allElems,
   return elems;
 }
 
-static bool isPath(const string& s) { return s.find('/') != string::npos; }
+static bool isPath(const std::string& s) {
+  return s.find('/') != std::string::npos;
+}
 
 static void queryInstSources(EvalState& state, InstallSourceInfo& instSource,
                              const Strings& args, DrvInfos& elems,
@@ -364,10 +367,10 @@ static void queryInstSources(EvalState& state, InstallSourceInfo& instSource,
       for (auto& i : args) {
         Path path = state.store->followLinksToStorePath(i);
 
-        string name = baseNameOf(path);
-        string::size_type dash = name.find('-');
-        if (dash != string::npos) {
-          name = string(name, dash + 1);
+        std::string name = baseNameOf(path);
+        std::string::size_type dash = name.find('-');
+        if (dash != std::string::npos) {
+          name = std::string(name, dash + 1);
         }
 
         DrvInfo elem(state, "", nullptr);
@@ -378,8 +381,9 @@ static void queryInstSources(EvalState& state, InstallSourceInfo& instSource,
           elem.setOutPath(
               state.store->derivationFromPath(path).findOutput("out"));
           if (name.size() >= drvExtension.size() &&
-              string(name, name.size() - drvExtension.size()) == drvExtension) {
-            name = string(name, 0, name.size() - drvExtension.size());
+              std::string(name, name.size() - drvExtension.size()) ==
+                  drvExtension) {
+            name = std::string(name, 0, name.size() - drvExtension.size());
           }
         } else {
           elem.setOutPath(path);
@@ -457,7 +461,7 @@ static void installDerivations(Globals& globals, const Strings& args,
   }
 
   while (true) {
-    string lockToken = optimisticLockProfile(profile);
+    std::string lockToken = optimisticLockProfile(profile);
 
     DrvInfos allElems(newElems);
 
@@ -496,7 +500,7 @@ static void installDerivations(Globals& globals, const Strings& args,
 
 static void opInstall(Globals& globals, Strings opFlags, Strings opArgs) {
   for (auto i = opFlags.begin(); i != opFlags.end();) {
-    string arg = *i++;
+    std::string arg = *i++;
     if (parseInstallSourceOptions(globals, i, opFlags, arg)) {
       ;
     } else if (arg == "--preserve-installed" || arg == "-P") {
@@ -523,7 +527,7 @@ static void upgradeDerivations(Globals& globals, const Strings& args,
      name and a higher version number. */
 
   while (true) {
-    string lockToken = optimisticLockProfile(globals.profile);
+    std::string lockToken = optimisticLockProfile(globals.profile);
 
     DrvInfos installedElems = queryInstalled(*globals.state, globals.profile);
 
@@ -551,7 +555,7 @@ static void upgradeDerivations(Globals& globals, const Strings& args,
            take the one with the highest version.
            Do not upgrade if it would decrease the priority. */
         auto bestElem = availElems.end();
-        string bestVersion;
+        std::string bestVersion;
         for (auto j = availElems.begin(); j != availElems.end(); ++j) {
           if (comparePriorities(*globals.state, i, *j) > 0) {
             continue;
@@ -614,7 +618,7 @@ static void upgradeDerivations(Globals& globals, const Strings& args,
 static void opUpgrade(Globals& globals, Strings opFlags, Strings opArgs) {
   UpgradeType upgradeType = utLt;
   for (auto i = opFlags.begin(); i != opFlags.end();) {
-    string arg = *i++;
+    std::string arg = *i++;
     if (parseInstallSourceOptions(globals, i, opFlags, arg)) {
       ;
     } else if (arg == "--lt") {
@@ -633,8 +637,8 @@ static void opUpgrade(Globals& globals, Strings opFlags, Strings opArgs) {
   upgradeDerivations(globals, opArgs, upgradeType);
 }
 
-static void setMetaFlag(EvalState& state, DrvInfo& drv, const string& name,
-                        const string& value) {
+static void setMetaFlag(EvalState& state, DrvInfo& drv, const std::string& name,
+                        const std::string& value) {
   Value* v = state.allocValue();
   mkString(*v, value.c_str());
   drv.setMeta(name, v);
@@ -649,12 +653,12 @@ static void opSetFlag(Globals& globals, Strings opFlags, Strings opArgs) {
   }
 
   auto arg = opArgs.begin();
-  string flagName = *arg++;
-  string flagValue = *arg++;
+  std::string flagName = *arg++;
+  std::string flagValue = *arg++;
   DrvNames selectors = drvNamesFromArgs(Strings(arg, opArgs.end()));
 
   while (true) {
-    string lockToken = optimisticLockProfile(globals.profile);
+    std::string lockToken = optimisticLockProfile(globals.profile);
 
     DrvInfos installedElems = queryInstalled(*globals.state, globals.profile);
 
@@ -688,7 +692,7 @@ static void opSet(Globals& globals, Strings opFlags, Strings opArgs) {
   }
 
   for (auto i = opFlags.begin(); i != opFlags.end();) {
-    string arg = *i++;
+    std::string arg = *i++;
     if (parseInstallSourceOptions(globals, i, opFlags, arg)) {
       ;
     } else {
@@ -734,7 +738,7 @@ static void opSet(Globals& globals, Strings opFlags, Strings opArgs) {
 static void uninstallDerivations(Globals& globals, Strings& selectors,
                                  Path& profile) {
   while (true) {
-    string lockToken = optimisticLockProfile(profile);
+    std::string lockToken = optimisticLockProfile(profile);
 
     DrvInfos installedElems = queryInstalled(*globals.state, profile);
     DrvInfos newElems;
@@ -786,12 +790,12 @@ static bool cmpElemByName(const DrvInfo& a, const DrvInfo& b) {
                                  b_name.end(), cmpChars);
 }
 
-using Table = list<Strings>;
+using Table = std::list<Strings>;
 
 void printTable(Table& table) {
   auto nrColumns = !table.empty() ? table.front().size() : 0;
 
-  vector<size_t> widths;
+  std::vector<size_t> widths;
   widths.resize(nrColumns);
 
   for (auto& i : table) {
@@ -809,11 +813,11 @@ void printTable(Table& table) {
     Strings::iterator j;
     size_t column;
     for (j = i.begin(), column = 0; j != i.end(); ++j, ++column) {
-      string s = *j;
+      std::string s = *j;
       replace(s.begin(), s.end(), '\n', ' ');
       cout << s;
       if (column < nrColumns - 1) {
-        cout << string(widths[column] - s.size() + 2, ' ');
+        cout << std::string(widths[column] - s.size() + 2, ' ');
       }
     }
     cout << std::endl;
@@ -831,7 +835,7 @@ typedef enum { cvLess, cvEqual, cvGreater, cvUnavail } VersionDiff;
 
 static VersionDiff compareVersionAgainstSet(const DrvInfo& elem,
                                             const DrvInfos& elems,
-                                            string& version) {
+                                            std::string& version) {
   DrvName name(elem.queryName());
 
   VersionDiff diff = cvUnavail;
@@ -859,7 +863,7 @@ static VersionDiff compareVersionAgainstSet(const DrvInfo& elem,
   return diff;
 }
 
-static void queryJSON(Globals& globals, vector<DrvInfo>& elems) {
+static void queryJSON(Globals& globals, std::vector<DrvInfo>& elems) {
   JSONObject topObj(cout, true);
   for (auto& i : elems) {
     JSONObject pkgObj = topObj.object(i.attrPath);
@@ -889,7 +893,7 @@ static void queryJSON(Globals& globals, vector<DrvInfo>& elems) {
 
 static void opQuery(Globals& globals, Strings opFlags, Strings opArgs) {
   Strings remaining;
-  string attrPath;
+  std::string attrPath;
 
   bool printStatus = false;
   bool printName = true;
@@ -908,7 +912,7 @@ static void opQuery(Globals& globals, Strings opFlags, Strings opArgs) {
   settings.readOnlyMode = true; /* makes evaluation a bit faster */
 
   for (auto i = opFlags.begin(); i != opFlags.end();) {
-    string arg = *i++;
+    std::string arg = *i++;
     if (arg == "--status" || arg == "-s") {
       printStatus = true;
     } else if (arg == "--no-name") {
@@ -964,7 +968,7 @@ static void opQuery(Globals& globals, Strings opFlags, Strings opArgs) {
 
   /* Sort them by name. */
   /* !!! */
-  vector<DrvInfo> elems;
+  std::vector<DrvInfo> elems;
   for (auto& i : elems_) {
     elems.push_back(i);
   }
@@ -1045,7 +1049,7 @@ static void opQuery(Globals& globals, Strings opFlags, Strings opArgs) {
           attrs["valid"] = isValid ? "1" : "0";
           attrs["substitutable"] = hasSubs ? "1" : "0";
         } else {
-          columns.push_back((string)(isInstalled ? "I" : "-") +
+          columns.push_back((std::string)(isInstalled ? "I" : "-") +
                             (isValid ? "P" : "-") + (hasSubs ? "S" : "-"));
         }
       }
@@ -1070,7 +1074,7 @@ static void opQuery(Globals& globals, Strings opFlags, Strings opArgs) {
            same named packages in either the set of available
            elements, or the set of installed elements.  !!!
            This is O(N * M), should be O(N * lg M). */
-        string version;
+        std::string version;
         VersionDiff diff = compareVersionAgainstSet(i, otherElems, version);
 
         char ch;
@@ -1097,7 +1101,7 @@ static void opQuery(Globals& globals, Strings opFlags, Strings opArgs) {
             attrs["maxComparedVersion"] = version;
           }
         } else {
-          string column = (string) "" + ch + " " + version;
+          std::string column = (std::string) "" + ch + " " + version;
           if (diff == cvGreater && tty) {
             column = ANSI_RED + column + ANSI_NORMAL;
           }
@@ -1114,7 +1118,7 @@ static void opQuery(Globals& globals, Strings opFlags, Strings opArgs) {
       }
 
       if (printDrvPath) {
-        string drvPath = i.queryDrvPath();
+        std::string drvPath = i.queryDrvPath();
         if (xmlOutput) {
           if (!drvPath.empty()) {
             attrs["drvPath"] = drvPath;
@@ -1126,7 +1130,7 @@ static void opQuery(Globals& globals, Strings opFlags, Strings opArgs) {
 
       if (printOutPath && !xmlOutput) {
         DrvInfo::Outputs outputs = i.queryOutputs();
-        string s;
+        std::string s;
         for (auto& j : outputs) {
           if (!s.empty()) {
             s += ';';
@@ -1141,7 +1145,7 @@ static void opQuery(Globals& globals, Strings opFlags, Strings opArgs) {
       }
 
       if (printDescription) {
-        string descr = i.queryMetaString("description");
+        std::string descr = i.queryMetaString("description");
         if (xmlOutput) {
           if (!descr.empty()) {
             attrs["description"] = descr;
@@ -1354,14 +1358,16 @@ static void opDeleteGenerations(Globals& globals, Strings opFlags,
 
   if (opArgs.size() == 1 && opArgs.front() == "old") {
     deleteOldGenerations(globals.profile, globals.dryRun);
-  } else if (opArgs.size() == 1 && opArgs.front().find('d') != string::npos) {
+  } else if (opArgs.size() == 1 &&
+             opArgs.front().find('d') != std::string::npos) {
     deleteGenerationsOlderThan(globals.profile, opArgs.front(), globals.dryRun);
-  } else if (opArgs.size() == 1 && opArgs.front().find('+') != string::npos) {
+  } else if (opArgs.size() == 1 &&
+             opArgs.front().find('+') != std::string::npos) {
     if (opArgs.front().size() < 2) {
       throw Error(format("invalid number of generations ‘%1%’") %
                   opArgs.front());
     }
-    string str_max = string(opArgs.front(), 1, opArgs.front().size());
+    string str_max = std::string(opArgs.front(), 1, opArgs.front().size());
     int max;
     if (!string2Int(str_max, max) || max == 0) {
       throw Error(format("invalid number of generations to keep ‘%1%’") %
@@ -1391,7 +1397,7 @@ static int _main(int argc, char** argv) {
     Strings opArgs;
     Operation op = nullptr;
     RepairFlag repair = NoRepair;
-    string file;
+    std::string file;
 
     Globals globals;
 
diff --git a/third_party/nix/src/nix-env/user-env.cc b/third_party/nix/src/nix-env/user-env.cc
index 2ca56ed96620..c8eee4aac09b 100644
--- a/third_party/nix/src/nix-env/user-env.cc
+++ b/third_party/nix/src/nix-env/user-env.cc
@@ -26,7 +26,7 @@ DrvInfos queryInstalled(EvalState& state, const Path& userEnv) {
 }
 
 bool createUserEnv(EvalState& state, DrvInfos& elems, const Path& profile,
-                   bool keepDerivations, const string& lockToken) {
+                   bool keepDerivations, const std::string& lockToken) {
   /* Build the components in the user environment, if they don't
      exist already. */
   PathSet drvsToBuild;
diff --git a/third_party/nix/src/nix-env/user-env.hh b/third_party/nix/src/nix-env/user-env.hh
index 6111b21c353d..a117d5c2ad67 100644
--- a/third_party/nix/src/nix-env/user-env.hh
+++ b/third_party/nix/src/nix-env/user-env.hh
@@ -7,6 +7,6 @@ namespace nix {
 DrvInfos queryInstalled(EvalState& state, const Path& userEnv);
 
 bool createUserEnv(EvalState& state, DrvInfos& elems, const Path& profile,
-                   bool keepDerivations, const string& lockToken);
+                   bool keepDerivations, const std::string& lockToken);
 
 }  // namespace nix
diff --git a/third_party/nix/src/nix-instantiate/nix-instantiate.cc b/third_party/nix/src/nix-instantiate/nix-instantiate.cc
index 95e5341ade4a..8e1c7afe1c91 100644
--- a/third_party/nix/src/nix-instantiate/nix-instantiate.cc
+++ b/third_party/nix/src/nix-instantiate/nix-instantiate.cc
@@ -62,7 +62,7 @@ void processExpr(EvalState& state, const Strings& attrPaths, bool parseOnly,
         Path drvPath = i.queryDrvPath();
 
         /* What output do we want? */
-        string outputName = i.queryOutputName();
+        std::string outputName = i.queryOutputName();
         if (outputName.empty()) {
           throw Error(
               format("derivation '%1%' lacks an 'outputName' attribute ") %
diff --git a/third_party/nix/src/nix-prefetch-url/nix-prefetch-url.cc b/third_party/nix/src/nix-prefetch-url/nix-prefetch-url.cc
index fa88dc9bc67e..a2cd570986e8 100644
--- a/third_party/nix/src/nix-prefetch-url/nix-prefetch-url.cc
+++ b/third_party/nix/src/nix-prefetch-url/nix-prefetch-url.cc
@@ -20,17 +20,17 @@ using namespace nix;
 
 /* If ‘uri’ starts with ‘mirror://’, then resolve it using the list of
    mirrors defined in Nixpkgs. */
-string resolveMirrorUri(EvalState& state, string uri) {
-  if (string(uri, 0, 9) != "mirror://") {
+std::string resolveMirrorUri(EvalState& state, std::string uri) {
+  if (std::string(uri, 0, 9) != "mirror://") {
     return uri;
   }
 
-  string s(uri, 9);
+  std::string s(uri, 9);
   auto p = s.find('/');
-  if (p == string::npos) {
+  if (p == std::string::npos) {
     throw Error("invalid mirror URI");
   }
-  string mirrorName(s, 0, p);
+  std::string mirrorName(s, 0, p);
 
   Value vMirrors;
   state.eval(
@@ -49,19 +49,20 @@ string resolveMirrorUri(EvalState& state, string uri) {
     throw Error(format("mirror URI '%1%' did not expand to anything") % uri);
   }
 
-  string mirror = state.forceString(*mirrorList->second.value->listElems()[0]);
-  return mirror + (hasSuffix(mirror, "/") ? "" : "/") + string(s, p + 1);
+  std::string mirror =
+      state.forceString(*mirrorList->second.value->listElems()[0]);
+  return mirror + (hasSuffix(mirror, "/") ? "" : "/") + std::string(s, p + 1);
 }
 
 static int _main(int argc, char** argv) {
   {
     HashType ht = htSHA256;
-    std::vector<string> args;
+    std::vector<std::string> args;
     bool printPath = !getEnv("PRINT_PATH").empty();
     bool fromExpr = false;
-    string attrPath;
+    std::string attrPath;
     bool unpack = false;
-    string name;
+    std::string name;
 
     struct MyArgs : LegacyArgs, MixEvalArgs {
       using LegacyArgs::LegacyArgs;
@@ -74,7 +75,7 @@ static int _main(int argc, char** argv) {
                     } else if (*arg == "--version") {
                       printVersion("nix-prefetch-url");
                     } else if (*arg == "--type") {
-                      string s = getArg(*arg, arg, end);
+                      std::string s = getArg(*arg, arg, end);
                       ht = parseHashType(s);
                       if (ht == htUnknown) {
                         throw UsageError(format("unknown hash type '%1%'") % s);
@@ -111,7 +112,7 @@ static int _main(int argc, char** argv) {
 
     /* If -A is given, get the URI from the specified Nix
        expression. */
-    string uri;
+    std::string uri;
     if (!fromExpr) {
       if (args.empty()) {
         throw UsageError("you must specify a URI");
diff --git a/third_party/nix/src/nix-store/dotgraph.cc b/third_party/nix/src/nix-store/dotgraph.cc
index 0186a7b22ebd..ef335bb5318d 100644
--- a/third_party/nix/src/nix-store/dotgraph.cc
+++ b/third_party/nix/src/nix-store/dotgraph.cc
@@ -9,23 +9,23 @@ using std::cout;
 
 namespace nix {
 
-static string dotQuote(const string& s) { return "\"" + s + "\""; }
+static std::string dotQuote(const std::string& s) { return "\"" + s + "\""; }
 
-static string nextColour() {
+static std::string nextColour() {
   static int n = 0;
-  static string colours[] = {"black", "red",     "green",
-                             "blue",  "magenta", "burlywood"};
-  return colours[n++ % (sizeof(colours) / sizeof(string))];
+  static std::string colours[] = {"black", "red",     "green",
+                                  "blue",  "magenta", "burlywood"};
+  return colours[n++ % (sizeof(colours) / sizeof(std::string))];
 }
 
-static string makeEdge(const string& src, const string& dst) {
+static std::string makeEdge(const std::string& src, const std::string& dst) {
   format f = format("%1% -> %2% [color = %3%];\n") % dotQuote(src) %
              dotQuote(dst) % dotQuote(nextColour());
   return f.str();
 }
 
-static string makeNode(const string& id, const string& label,
-                       const string& colour) {
+static std::string makeNode(const std::string& id, const std::string& label,
+                            const std::string& colour) {
   format f = format(
                  "%1% [label = %2%, shape = box, "
                  "style = filled, fillcolor = %3%];\n") %
@@ -33,15 +33,15 @@ static string makeNode(const string& id, const string& label,
   return f.str();
 }
 
-static string symbolicName(const string& path) {
-  string p = baseNameOf(path);
-  return string(p, p.find('-') + 1);
+static std::string symbolicName(const std::string& path) {
+  std::string p = baseNameOf(path);
+  return std::string(p, p.find('-') + 1);
 }
 
 #if 0
-string pathLabel(const Path & nePath, const string & elemPath)
+std::string pathLabel(const Path & nePath, const std::string & elemPath)
 {
-    return (string) nePath + "-" + elemPath;
+    return (std::string) nePath + "-" + elemPath;
 }
 
 
diff --git a/third_party/nix/src/nix-store/graphml.cc b/third_party/nix/src/nix-store/graphml.cc
index a1a16cc8f28a..86b1c6b94231 100644
--- a/third_party/nix/src/nix-store/graphml.cc
+++ b/third_party/nix/src/nix-store/graphml.cc
@@ -10,23 +10,23 @@ using std::cout;
 
 namespace nix {
 
-static inline const string& xmlQuote(const string& s) {
+static inline const std::string& xmlQuote(const std::string& s) {
   // Luckily, store paths shouldn't contain any character that needs to be
   // quoted.
   return s;
 }
 
-static string symbolicName(const string& path) {
-  string p = baseNameOf(path);
-  return string(p, p.find('-') + 1);
+static std::string symbolicName(const std::string& path) {
+  std::string p = baseNameOf(path);
+  return std::string(p, p.find('-') + 1);
 }
 
-static string makeEdge(const string& src, const string& dst) {
+static std::string makeEdge(const std::string& src, const std::string& dst) {
   return fmt("  <edge source=\"%1%\" target=\"%2%\"/>\n", xmlQuote(src),
              xmlQuote(dst));
 }
 
-static string makeNode(const ValidPathInfo& info) {
+static std::string makeNode(const ValidPathInfo& info) {
   return fmt(
       "  <node id=\"%1%\">\n"
       "    <data key=\"narSize\">%2%</data>\n"
diff --git a/third_party/nix/src/nix-store/nix-store.cc b/third_party/nix/src/nix-store/nix-store.cc
index 40d6f01cd96c..713439308ae8 100644
--- a/third_party/nix/src/nix-store/nix-store.cc
+++ b/third_party/nix/src/nix-store/nix-store.cc
@@ -252,8 +252,8 @@ static void opPrintFixedPath(Strings opFlags, Strings opArgs) {
 
   auto i = opArgs.begin();
   HashType hashAlgo = parseHashType(*i++);
-  string hash = *i++;
-  string name = *i++;
+  std::string hash = *i++;
+  std::string name = *i++;
 
   cout << format("%1%\n") %
               store->makeFixedOutputPath(recursive, Hash(hash, hashAlgo), name);
@@ -279,12 +279,12 @@ static PathSet maybeUseOutputs(const Path& storePath, bool useOutput,
    graph.  Topological sorting is used to keep the tree relatively
    flat. */
 
-const string treeConn = "+---";
-const string treeLine = "|   ";
-const string treeNull = "    ";
+const std::string treeConn = "+---";
+const std::string treeLine = "|   ";
+const std::string treeNull = "    ";
 
-static void printTree(const Path& path, const string& firstPad,
-                      const string& tailPad, PathSet& done) {
+static void printTree(const Path& path, const std::string& firstPad,
+                      const std::string& tailPad, PathSet& done) {
   if (done.find(path) != done.end()) {
     cout << format("%1%%2% [...]\n") % firstPad % path;
     return;
@@ -334,7 +334,7 @@ static void opQuery(Strings opFlags, Strings opArgs) {
   bool useOutput = false;
   bool includeOutputs = false;
   bool forceRealise = false;
-  string bindingName;
+  std::string bindingName;
 
   for (auto& i : opFlags) {
     QueryType prev = query;
@@ -776,7 +776,7 @@ static void opDump(Strings opFlags, Strings opArgs) {
   }
 
   FdSink sink(STDOUT_FILENO);
-  string path = *opArgs.begin();
+  std::string path = *opArgs.begin();
   dumpPath(path, sink);
   sink.flush();
 }
@@ -1154,9 +1154,9 @@ static void opGenerateBinaryCacheKey(Strings opFlags, Strings opArgs) {
     throw UsageError("three arguments expected");
   }
   auto i = opArgs.begin();
-  string keyName = *i++;
-  string secretKeyFile = *i++;
-  string publicKeyFile = *i++;
+  std::string keyName = *i++;
+  std::string secretKeyFile = *i++;
+  std::string publicKeyFile = *i++;
 
 #if HAVE_SODIUM
   if (sodium_init() == -1) {
@@ -1169,13 +1169,13 @@ static void opGenerateBinaryCacheKey(Strings opFlags, Strings opArgs) {
     throw Error("key generation failed");
   }
 
-  writeFile(publicKeyFile,
-            keyName + ":" +
-                base64Encode(string((char*)pk, crypto_sign_PUBLICKEYBYTES)));
+  writeFile(publicKeyFile, keyName + ":" +
+                               base64Encode(std::string(
+                                   (char*)pk, crypto_sign_PUBLICKEYBYTES)));
   umask(0077);
-  writeFile(secretKeyFile,
-            keyName + ":" +
-                base64Encode(string((char*)sk, crypto_sign_SECRETKEYBYTES)));
+  writeFile(secretKeyFile, keyName + ":" +
+                               base64Encode(std::string(
+                                   (char*)sk, crypto_sign_SECRETKEYBYTES)));
 #else
   throw Error(
       "Nix was not compiled with libsodium, required for signed binary cache "
diff --git a/third_party/nix/src/nix/command.cc b/third_party/nix/src/nix/command.cc
index 439f22dc3b67..34fcde80033e 100644
--- a/third_party/nix/src/nix/command.cc
+++ b/third_party/nix/src/nix/command.cc
@@ -9,7 +9,7 @@ namespace nix {
 
 Commands* RegisterCommand::commands = nullptr;
 
-void Command::printHelp(const string& programName, std::ostream& out) {
+void Command::printHelp(const std::string& programName, std::ostream& out) {
   Args::printHelp(programName, out);
 
   auto exs = examples();
@@ -37,7 +37,8 @@ MultiCommand::MultiCommand(Commands _commands)
       }});
 }
 
-void MultiCommand::printHelp(const string& programName, std::ostream& out) {
+void MultiCommand::printHelp(const std::string& programName,
+                             std::ostream& out) {
   if (command) {
     command->printHelp(programName + " " + command->name(), out);
     return;
diff --git a/third_party/nix/src/nix/command.hh b/third_party/nix/src/nix/command.hh
index 4122bdd0e58f..c297bfbd38dd 100644
--- a/third_party/nix/src/nix/command.hh
+++ b/third_party/nix/src/nix/command.hh
@@ -27,7 +27,7 @@ struct Command : virtual Args {
 
   virtual Examples examples() { return Examples(); }
 
-  void printHelp(const string& programName, std::ostream& out) override;
+  void printHelp(const std::string& programName, std::ostream& out) override;
 };
 
 class Store;
@@ -151,7 +151,7 @@ class MultiCommand : virtual Args {
 
   MultiCommand(Commands commands);
 
-  void printHelp(const string& programName, std::ostream& out) override;
+  void printHelp(const std::string& programName, std::ostream& out) override;
 
   bool processFlag(Strings::iterator& pos, Strings::iterator end) override;
 
diff --git a/third_party/nix/src/nix/hash.cc b/third_party/nix/src/nix/hash.cc
index 74ff45d0d84e..c500dc4f3ca6 100644
--- a/third_party/nix/src/nix/hash.cc
+++ b/third_party/nix/src/nix/hash.cc
@@ -106,7 +106,7 @@ static int compatNixHash(int argc, char** argv) {
                  } else if (*arg == "--truncate") {
                    truncate = true;
                  } else if (*arg == "--type") {
-                   string s = getArg(*arg, arg, end);
+                   std::string s = getArg(*arg, arg, end);
                    ht = parseHashType(s);
                    if (ht == htUnknown) {
                      throw UsageError(format("unknown hash type '%1%'") % s);
diff --git a/third_party/nix/src/nix/main.cc b/third_party/nix/src/nix/main.cc
index 11ba3f8410c4..59782388087a 100644
--- a/third_party/nix/src/nix/main.cc
+++ b/third_party/nix/src/nix/main.cc
@@ -129,7 +129,7 @@ void mainWrapped(int argc, char** argv) {
   initGC();
 
   programPath = argv[0];
-  string programName = baseNameOf(programPath);
+  std::string programName = baseNameOf(programPath);
 
   {
     auto legacy = (*RegisterLegacyCommand::commands)[programName];
diff --git a/third_party/nix/src/nix/repl.cc b/third_party/nix/src/nix/repl.cc
index 5db9468fdc0a..e2e4de6fec1b 100644
--- a/third_party/nix/src/nix/repl.cc
+++ b/third_party/nix/src/nix/repl.cc
@@ -46,7 +46,7 @@ namespace nix {
 #define ESC_END "\033[0m"
 
 struct NixRepl {
-  string curDir;
+  std::string curDir;
   EvalState state;
   Bindings* autoArgs;
 
@@ -63,19 +63,19 @@ struct NixRepl {
   NixRepl(const Strings& searchPath, const nix::ref<Store>& store);
   ~NixRepl();
   void mainLoop(const std::vector<std::string>& files);
-  StringSet completePrefix(const string& prefix);
-  static bool getLine(string& input, const std::string& prompt);
+  StringSet completePrefix(const std::string& prefix);
+  static bool getLine(std::string& input, const std::string& prompt);
   Path getDerivationPath(Value& v);
-  bool processLine(string line);
+  bool processLine(std::string line);
   void loadFile(const Path& path);
   void initEnv();
   void reloadFiles();
   void addAttrsToScope(Value& attrs);
   void addVarToScope(const Symbol& name, Value& v);
-  Expr* parseString(const string& s);
-  void evalString(string s, Value& v);
+  Expr* parseString(const std::string& s);
+  void evalString(std::string s, Value& v);
 
-  using ValuesSeen = set<Value*>;
+  using ValuesSeen = std::set<Value*>;
   std::ostream& printValue(std::ostream& str, Value& v, unsigned int maxDepth);
   std::ostream& printValue(std::ostream& str, Value& v, unsigned int maxDepth,
                            ValuesSeen& seen);
@@ -122,11 +122,11 @@ void printHelp() {
             << "        at least a file named default.nix.\n";
 }
 
-string removeWhitespace(string s) {
+std::string removeWhitespace(std::string s) {
   s = absl::StripTrailingAsciiWhitespace(s);
   size_t n = s.find_first_not_of(" \n\r\t");
-  if (n != string::npos) {
-    s = string(s, n);
+  if (n != std::string::npos) {
+    s = std::string(s, n);
   }
   return s;
 }
@@ -224,7 +224,7 @@ void sigintHandler(int signo) { g_signal_received = signo; }
 }  // namespace
 
 void NixRepl::mainLoop(const std::vector<std::string>& files) {
-  string error = ANSI_RED "error:" ANSI_NORMAL " ";
+  std::string error = ANSI_RED "error:" ANSI_NORMAL " ";
   std::cout << "Welcome to Nix version " << nixVersion << ". Type :? for help."
             << std::endl
             << std::endl;
@@ -285,7 +285,7 @@ void NixRepl::mainLoop(const std::vector<std::string>& files) {
   }
 }
 
-bool NixRepl::getLine(string& input, const std::string& prompt) {
+bool NixRepl::getLine(std::string& input, const std::string& prompt) {
   struct sigaction act;
   struct sigaction old;
   sigset_t savedSignalMask;
@@ -334,7 +334,7 @@ bool NixRepl::getLine(string& input, const std::string& prompt) {
   return true;
 }
 
-StringSet NixRepl::completePrefix(const string& prefix) {
+StringSet NixRepl::completePrefix(const std::string& prefix) {
   StringSet completions;
 
   size_t start = prefix.find_last_of(" \n\r\t(){}[]");
@@ -351,7 +351,7 @@ StringSet NixRepl::completePrefix(const string& prefix) {
   size_t slash;
   size_t dot;
 
-  if ((slash = cur.rfind('/')) != string::npos) {
+  if ((slash = cur.rfind('/')) != std::string::npos) {
     try {
       auto dir = std::string(cur, 0, slash);
       auto prefix2 = std::string(cur, slash + 1);
@@ -362,11 +362,11 @@ StringSet NixRepl::completePrefix(const string& prefix) {
       }
     } catch (Error&) {
     }
-  } else if ((dot = cur.rfind('.')) == string::npos) {
+  } else if ((dot = cur.rfind('.')) == std::string::npos) {
     /* This is a variable name; look it up in the current scope. */
     auto i = varNames.lower_bound(cur);
     while (i != varNames.end()) {
-      if (string(*i, 0, cur.size()) != cur) {
+      if (std::string(*i, 0, cur.size()) != cur) {
         break;
       }
       completions.insert(prev + *i);
@@ -377,8 +377,8 @@ StringSet NixRepl::completePrefix(const string& prefix) {
       /* This is an expression that should evaluate to an
          attribute set.  Evaluate it to get the names of the
          attributes. */
-      string expr(cur, 0, dot);
-      string cur2 = string(cur, dot + 1);
+      std::string expr(cur, 0, dot);
+      std::string cur2 = std::string(cur, dot + 1);
 
       Expr* e = parseString(expr);
       Value v;
@@ -386,8 +386,8 @@ StringSet NixRepl::completePrefix(const string& prefix) {
       state.forceAttrs(v);
 
       for (auto& i : *v.attrs) {
-        string name = i.second.name;
-        if (string(name, 0, cur2.size()) != cur2) {
+        std::string name = i.second.name;
+        if (std::string(name, 0, cur2.size()) != cur2) {
           continue;
         }
         completions.insert(prev + expr + "." + name);
@@ -405,7 +405,7 @@ StringSet NixRepl::completePrefix(const string& prefix) {
   return completions;
 }
 
-static int runProgram(const string& program, const Strings& args) {
+static int runProgram(const std::string& program, const Strings& args) {
   Strings args2(args);
   args2.push_front(program);
 
@@ -423,7 +423,7 @@ static int runProgram(const string& program, const Strings& args) {
   return pid.wait();
 }
 
-bool isVarName(const string& s) {
+bool isVarName(const std::string& s) {
   if (s.empty()) {
     return false;
   }
@@ -453,19 +453,19 @@ Path NixRepl::getDerivationPath(Value& v) {
   return drvPath;
 }
 
-bool NixRepl::processLine(string line) {
+bool NixRepl::processLine(std::string line) {
   if (line.empty()) {
     return true;
   }
 
-  string command;
-  string arg;
+  std::string command;
+  std::string arg;
 
   if (line[0] == ':') {
     size_t p = line.find_first_of(" \n\r\t");
-    command = string(line, 0, p);
-    if (p != string::npos) {
-      arg = removeWhitespace(string(line, p));
+    command = std::string(line, 0, p);
+    if (p != std::string::npos) {
+      arg = removeWhitespace(std::string(line, p));
     }
   } else {
     arg = line;
@@ -567,10 +567,10 @@ bool NixRepl::processLine(string line) {
 
   } else {
     size_t p = line.find('=');
-    string name;
-    if (p != string::npos && p < line.size() && line[p + 1] != '=' &&
-        isVarName(name = removeWhitespace(string(line, 0, p)))) {
-      Expr* e = parseString(string(line, p + 1));
+    std::string name;
+    if (p != std::string::npos && p < line.size() && line[p + 1] != '=' &&
+        isVarName(name = removeWhitespace(std::string(line, 0, p)))) {
+      Expr* e = parseString(std::string(line, p + 1));
       Value& v(*state.allocValue());
       v.type = tThunk;
       v.thunk.env = env;
@@ -640,15 +640,15 @@ void NixRepl::addVarToScope(const Symbol& name, Value& v) {
   }
   staticEnv.vars[name] = displ;
   env->values[displ++] = &v;
-  varNames.insert((string)name);
+  varNames.insert((std::string)name);
 }
 
-Expr* NixRepl::parseString(const string& s) {
+Expr* NixRepl::parseString(const std::string& s) {
   Expr* e = state.parseExprFromString(s, curDir, staticEnv);
   return e;
 }
 
-void NixRepl::evalString(string s, Value& v) {
+void NixRepl::evalString(std::string s, Value& v) {
   Expr* e = parseString(std::move(s));
   e->eval(state, *env, v);
   state.forceValue(v);
@@ -729,7 +729,7 @@ std::ostream& NixRepl::printValue(std::ostream& str, Value& v,
       else if (maxDepth > 0) {
         str << "{ ";
 
-        typedef std::map<string, Value*> Sorted;
+        typedef std::map<std::string, Value*> Sorted;
         Sorted sorted;
         for (auto& i : *v.attrs) {
           sorted[i.second.name] = i.second.value;
diff --git a/third_party/nix/src/nix/why-depends.cc b/third_party/nix/src/nix/why-depends.cc
index bbbfd1fe0182..9c5eaf737c03 100644
--- a/third_party/nix/src/nix/why-depends.cc
+++ b/third_party/nix/src/nix/why-depends.cc
@@ -133,16 +133,18 @@ struct CmdWhyDepends : SourceExprCommand {
        closure (i.e., that have a non-infinite distance to
        'dependency'). Print every edge on a path between `package`
        and `dependency`. */
-    std::function<void(Node&, const string&, const string&)> printNode;
+    std::function<void(Node&, const std::string&, const std::string&)>
+        printNode;
 
-    const string treeConn = "╠═══";
-    const string treeLast = "╚═══";
-    const string treeLine = "║   ";
-    const string treeNull = "    ";
+    const std::string treeConn = "╠═══";
+    const std::string treeLast = "╚═══";
+    const std::string treeLine = "║   ";
+    const std::string treeNull = "    ";
 
     struct BailOut {};
 
-    printNode = [&](Node& node, const string& firstPad, const string& tailPad) {
+    printNode = [&](Node& node, const std::string& firstPad,
+                    const std::string& tailPad) {
       assert(node.dist != inf);
       std::cout << fmt("%s%s%s%s" ANSI_NORMAL "\n", firstPad,
                        node.visited ? "\e[38;5;244m" : "",