daemon: Remove ‘foreach’ and ‘foreach_reverse’

‘foreach_reverse’ is not used anywhere

* nix/libutil/util.hh (foreach, foreach_reverse): Remove.
* nix/libstore/build.cc (addToWeakGoals): Use ‘std::none_of’ instead of macro ‘foreach’.
(Goal::waiteeDone, Goal::amDone, UserLock::acquire, rewriteHashes,
DerivationGoal::addWantedOutputs, DerivationGoal::haveDerivation,
DerivationGoal::outputsSubstituted, DerivationGoal::repairClosure,
DerivationGoal::inputsRealised, DerivationGoal::tryToBuild,
DerivationGoal::buildDone, DerivationGoal::tryBuildHook,
DerivationGoal::startBuilder, DerivationGoal::runChild,
parseReferenceSpecifiers, DerivationGoal::registerOutputs,
DerivationGoal::checkPathValidity, SubstitutionGoal::tryNext,
SubstitutionGoal::referencesValid, Worker::removeGoal,
Worker::childTerminated, Worker::run, Worker::waitForInput): Use range-based
‘for’ instead of macro ‘foreach’.
* nix/libstore/derivations.cc (writeDerivation, unparseDerivation,
hashDerivationModulo): Likewise.
* nix/libstore/gc.cc (addAdditionalRoots, LocalStore::deletePathRecursive,
LocalStore::canReachRoot, LocalStore::collectGarbage): Likewise.
* nix/libstore/globals.cc (Settings::pack): Likewise.
* nix/libstore/local-store.cc (checkDerivationOutputs, queryValidPaths,
querySubstitutablePaths, querySubstitutablePathInfos, registerValidPaths, verifyStore,
verifyPath): Likewise.
* nix/libstore/misc.cc (computeFSClosure, dfsVisit, topoSortPaths): Likewise.
* nix/libstore/optimise-store.cc (LocalStore::optimisePath_, LocalStore::optimiseStore): Likewise.
* nix/libstore/pathlocks.cc (PathLocks::lockPaths, PathLocks::~PathLocks): Likewise.
* nix/libstore/references.cc (search, scanForReferences): Likewise.
* nix/libstore/store-api.cc (checkStoreName, computeStorePathForText,
StoreAPI::makeValidityRegistration, showPaths, readStorePaths): Likewise.
* nix/libutil/serialise.cc (writeStrings): Likewise.
* nix/libutil/util.cc (concatStringsSep): Likewise.
* nix/nix-daemon/nix-daemon.cc (performOp): Likewise.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

14 files changed, 327 insertions, 334 deletions

diff --git a/nix/libstore/build.cc b/nix/libstore/build.cc
index 47e93d1a211..afdcd9518b3 100644
--- a/nix/libstore/build.cc
+++ b/nix/libstore/build.cc
@@ -336,9 +336,9 @@ void addToWeakGoals(WeakGoals & goals, GoalPtr p)
 {
     // FIXME: necessary?
     // FIXME: O(n)
-    foreach (WeakGoals::iterator, i, goals)
-        if (i->lock() == p) return;
-    goals.push_back(p);
+    bool b = std::none_of(goals.begin(), goals.end(),
+        [p](WeakGoalPtr i) { return i.lock() == p; });
+    if (b) goals.push_back(p); else return;
 }
 
 
@@ -367,11 +367,11 @@ void Goal::waiteeDone(GoalPtr waitee, ExitCode result)
 
         /* If we failed and keepGoing is not set, we remove all
            remaining waitees. */
-        foreach (Goals::iterator, i, waitees) {
-            GoalPtr goal = *i;
+        for (auto& i : waitees) {
+            GoalPtr goal = i;
             WeakGoals waiters2;
-            foreach (WeakGoals::iterator, j, goal->waiters)
-                if (j->lock() != shared_from_this()) waiters2.push_back(*j);
+            for (auto& j : goal->waiters)
+                if (j.lock() != shared_from_this()) waiters2.push_back(j);
             goal->waiters = waiters2;
         }
         waitees.clear();
@@ -387,8 +387,8 @@ void Goal::amDone(ExitCode result)
     assert(exitCode == ecBusy);
     assert(result == ecSuccess || result == ecFailed || result == ecNoSubstituters || result == ecIncompleteClosure);
     exitCode = result;
-    foreach (WeakGoals::iterator, i, waiters) {
-        GoalPtr goal = i->lock();
+    for (auto& i : waiters) {
+        GoalPtr goal = i.lock();
         if (goal) goal->waiteeDone(shared_from_this(), result);
     }
     waiters.clear();
@@ -498,13 +498,13 @@ void UserLock::acquire()
 
     /* Find a user account that isn't currently in use for another
        build. */
-    foreach (Strings::iterator, i, users) {
-        debug(format("trying user `%1%'") % *i);
+    for (auto& i : users) {
+        debug(format("trying user `%1%'") % i);
 
-        struct passwd * pw = getpwnam(i->c_str());
+        struct passwd * pw = getpwnam(i.c_str());
         if (!pw)
             throw Error(format("the user `%1%' in the group `%2%' does not exist")
-                % *i % settings.buildUsersGroup);
+                % i % settings.buildUsersGroup);
 
         createDirs(settings.nixStateDir + "/userpool");
 
@@ -522,7 +522,7 @@ void UserLock::acquire()
         if (lockFile(fd, ltWrite, false)) {
             fdUserLock = fd.borrow();
             lockedPaths.insert(fnUserLock);
-            user = *i;
+            user = i;
             uid = pw->pw_uid;
 
             /* Sanity check... */
@@ -576,12 +576,12 @@ typedef map<string, string> HashRewrites;
 
 string rewriteHashes(string s, const HashRewrites & rewrites)
 {
-    foreach (HashRewrites::const_iterator, i, rewrites) {
-        assert(i->first.size() == i->second.size());
+    for (auto& i : rewrites) {
+        assert(i.first.size() == i.second.size());
         size_t j = 0;
-        while ((j = s.find(i->first, j)) != string::npos) {
+        while ((j = s.find(i.first, j)) != string::npos) {
             debug(format("rewriting @ %1%") % j);
-            s.replace(j, i->second.size(), i->second);
+            s.replace(j, i.second.size(), i.second);
         }
     }
     return s;
@@ -884,9 +884,9 @@ void DerivationGoal::addWantedOutputs(const StringSet & outputs)
         wantedOutputs.clear();
         needRestart = true;
     } else
-        foreach (StringSet::const_iterator, i, outputs)
-            if (wantedOutputs.find(*i) == wantedOutputs.end()) {
-                wantedOutputs.insert(*i);
+        for (const auto& i : outputs)
+            if (wantedOutputs.find(i) == wantedOutputs.end()) {
+                wantedOutputs.insert(i);
                 needRestart = true;
             }
 }
@@ -933,8 +933,8 @@ void DerivationGoal::haveDerivation()
     /* Get the derivation. */
     drv = derivationFromPath(worker.store, drvPath);
 
-    foreach (DerivationOutputs::iterator, i, drv.outputs)
-        worker.store.addTempRoot(i->second.path);
+    for (auto& i : drv.outputs)
+        worker.store.addTempRoot(i.second.path);
 
     /* Check what outputs paths are not already valid. */
     PathSet invalidOutputs = checkPathValidity(false, buildMode == bmRepair);
@@ -947,15 +947,15 @@ void DerivationGoal::haveDerivation()
 
     /* Check whether any output previously failed to build.  If so,
        don't bother. */
-    foreach (PathSet::iterator, i, invalidOutputs)
-        if (pathFailed(*i)) return;
+    for (auto& i : invalidOutputs)
+        if (pathFailed(i)) return;
 
     /* We are first going to try to create the invalid output paths
        through substitutes.  If that doesn't work, we'll build
        them. */
     if (settings.useSubstitutes && substitutesAllowed(drv))
-        foreach (PathSet::iterator, i, invalidOutputs)
-            addWaitee(worker.makeSubstitutionGoal(*i, buildMode == bmRepair));
+        for (auto& i : invalidOutputs)
+            addWaitee(worker.makeSubstitutionGoal(i, buildMode == bmRepair));
 
     if (waitees.empty()) /* to prevent hang (no wake-up event) */
         outputsSubstituted();
@@ -1004,11 +1004,11 @@ void DerivationGoal::outputsSubstituted()
     wantedOutputs = PathSet();
 
     /* The inputs must be built before we can build this goal. */
-    foreach (DerivationInputs::iterator, i, drv.inputDrvs)
-        addWaitee(worker.makeDerivationGoal(i->first, i->second, buildMode == bmRepair ? bmRepair : bmNormal));
+    for (auto& i : drv.inputDrvs)
+        addWaitee(worker.makeDerivationGoal(i.first, i.second, buildMode == bmRepair ? bmRepair : bmNormal));
 
-    foreach (PathSet::iterator, i, drv.inputSrcs)
-        addWaitee(worker.makeSubstitutionGoal(*i));
+    for (auto& i : drv.inputSrcs)
+        addWaitee(worker.makeSubstitutionGoal(i));
 
     if (waitees.empty()) /* to prevent hang (no wake-up event) */
         inputsRealised();
@@ -1026,14 +1026,14 @@ void DerivationGoal::repairClosure()
 
     /* Get the output closure. */
     PathSet outputClosure;
-    foreach (DerivationOutputs::iterator, i, drv.outputs) {
-        if (!wantOutput(i->first, wantedOutputs)) continue;
-        computeFSClosure(worker.store, i->second.path, outputClosure);
+    for (auto& i : drv.outputs) {
+        if (!wantOutput(i.first, wantedOutputs)) continue;
+        computeFSClosure(worker.store, i.second.path, outputClosure);
     }
 
     /* Filter out our own outputs (which we have already checked). */
-    foreach (DerivationOutputs::iterator, i, drv.outputs)
-        outputClosure.erase(i->second.path);
+    for (auto& i : drv.outputs)
+        outputClosure.erase(i.second.path);
 
     /* Get all dependencies of this derivation so that we know which
        derivation is responsible for which path in the output
@@ -1041,21 +1041,21 @@ void DerivationGoal::repairClosure()
     PathSet inputClosure;
     computeFSClosure(worker.store, drvPath, inputClosure);
     std::map<Path, Path> outputsToDrv;
-    foreach (PathSet::iterator, i, inputClosure)
-        if (isDerivation(*i)) {
-            Derivation drv = derivationFromPath(worker.store, *i);
-            foreach (DerivationOutputs::iterator, j, drv.outputs)
-                outputsToDrv[j->second.path] = *i;
+    for (auto& i : inputClosure)
+        if (isDerivation(i)) {
+            Derivation drv = derivationFromPath(worker.store, i);
+            for (auto& j : drv.outputs)
+                outputsToDrv[j.second.path] = i;
         }
 
     /* Check each path (slow!). */
     PathSet broken;
-    foreach (PathSet::iterator, i, outputClosure) {
-        if (worker.store.pathContentsGood(*i)) continue;
-        printMsg(lvlError, format("found corrupted or missing path `%1%' in the output closure of `%2%'") % *i % drvPath);
-        Path drvPath2 = outputsToDrv[*i];
+    for (auto& i : outputClosure) {
+        if (worker.store.pathContentsGood(i)) continue;
+        printMsg(lvlError, format("found corrupted or missing path `%1%' in the output closure of `%2%'") % i % drvPath);
+        Path drvPath2 = outputsToDrv[i];
         if (drvPath2 == "")
-            addWaitee(worker.makeSubstitutionGoal(*i, true));
+            addWaitee(worker.makeSubstitutionGoal(i, true));
         else
             addWaitee(worker.makeDerivationGoal(drvPath2, PathSet(), bmRepair));
     }
@@ -1099,32 +1099,32 @@ void DerivationGoal::inputsRealised()
        running the build hook. */
 
     /* The outputs are referenceable paths. */
-    foreach (DerivationOutputs::iterator, i, drv.outputs) {
-        debug(format("building path `%1%'") % i->second.path);
-        allPaths.insert(i->second.path);
+    for (auto& i : drv.outputs) {
+        debug(format("building path `%1%'") % i.second.path);
+        allPaths.insert(i.second.path);
     }
 
     /* Determine the full set of input paths. */
 
     /* First, the input derivations. */
-    foreach (DerivationInputs::iterator, i, drv.inputDrvs) {
+    for (auto& i : drv.inputDrvs) {
         /* Add the relevant output closures of the input derivation
            `*i' as input paths.  Only add the closures of output paths
            that are specified as inputs. */
-        assert(worker.store.isValidPath(i->first));
-        Derivation inDrv = derivationFromPath(worker.store, i->first);
-        foreach (StringSet::iterator, j, i->second)
-            if (inDrv.outputs.find(*j) != inDrv.outputs.end())
-                computeFSClosure(worker.store, inDrv.outputs[*j].path, inputPaths);
+        assert(worker.store.isValidPath(i.first));
+        Derivation inDrv = derivationFromPath(worker.store, i.first);
+        for (auto& j : i.second)
+            if (inDrv.outputs.find(j) != inDrv.outputs.end())
+                computeFSClosure(worker.store, inDrv.outputs[j].path, inputPaths);
             else
                 throw Error(
                     format("derivation `%1%' requires non-existent output `%2%' from input derivation `%3%'")
-                    % drvPath % *j % i->first);
+                    % drvPath % j % i.first);
     }
 
     /* Second, the input sources. */
-    foreach (PathSet::iterator, i, drv.inputSrcs)
-        computeFSClosure(worker.store, *i, inputPaths);
+    for (auto& i : drv.inputSrcs)
+        computeFSClosure(worker.store, i, inputPaths);
 
     debug(format("added input paths %1%") % showPaths(inputPaths));
 
@@ -1186,10 +1186,10 @@ void DerivationGoal::tryToBuild()
        (It can't happen between here and the lockPaths() call below
        because we're not allowing multi-threading.)  If so, put this
        goal to sleep until another goal finishes, then try again. */
-    foreach (DerivationOutputs::iterator, i, drv.outputs)
-        if (pathIsLockedByMe(i->second.path)) {
+    for (auto& i : drv.outputs)
+        if (pathIsLockedByMe(i.second.path)) {
             debug(format("putting derivation `%1%' to sleep because `%2%' is locked by another goal")
-                % drvPath % i->second.path);
+                % drvPath % i.second.path);
             worker.waitForAnyGoal(shared_from_this());
             return;
         }
@@ -1222,12 +1222,12 @@ void DerivationGoal::tryToBuild()
 
     missingPaths = outputPaths(drv);
     if (buildMode != bmCheck)
-        foreach (PathSet::iterator, i, validPaths) missingPaths.erase(*i);
+        for (auto& i : validPaths) missingPaths.erase(i);
 
     /* If any of the outputs already exist but are not valid, delete
        them. */
-    foreach (DerivationOutputs::iterator, i, drv.outputs) {
-        Path path = i->second.path;
+    for (auto& i : drv.outputs) {
+        Path path = i.second.path;
         if (worker.store.isValidPath(path)) continue;
         if (!pathExists(path)) continue;
         debug(format("removing invalid path `%1%'") % path);
@@ -1237,8 +1237,8 @@ void DerivationGoal::tryToBuild()
     /* Check again whether any output previously failed to build,
        because some other process may have tried and failed before we
        acquired the lock. */
-    foreach (DerivationOutputs::iterator, i, drv.outputs)
-        if (pathFailed(i->second.path)) return;
+    for (auto& i : drv.outputs)
+        if (pathFailed(i.second.path)) return;
 
     /* Don't do a remote build if the derivation has the attribute
        `preferLocalBuild' set.  Also, check and repair modes are only
@@ -1415,11 +1415,11 @@ void DerivationGoal::buildDone()
             /* Move paths out of the chroot for easier debugging of
                build failures. */
             if (useChroot && buildMode == bmNormal)
-                foreach (PathSet::iterator, i, missingPaths)
-                    if (pathExists(chrootRootDir + *i)) {
+                for (auto& i : missingPaths)
+                    if (pathExists(chrootRootDir + i)) {
                       try {
-                        secureFilePerms(chrootRootDir + *i);
-                        rename((chrootRootDir + *i).c_str(), i->c_str());
+                        secureFilePerms(chrootRootDir + i);
+                        rename((chrootRootDir + i).c_str(), i.c_str());
                       } catch(Error & e) {
                         printMsg(lvlError, e.msg());
                       }
@@ -1436,8 +1436,8 @@ void DerivationGoal::buildDone()
             /* Replace the output, if it exists, by a fresh copy of itself to
                make sure that there's no stale file descriptor pointing to it
                (CVE-2024-27297).  */
-            foreach (DerivationOutputs::iterator, i, drv.outputs) {
-                Path output = chrootRootDir + i->second.path;
+            for (auto& i : drv.outputs) {
+                Path output = chrootRootDir + i.second.path;
                 if (pathExists(output)) {
                     Path pivot = output + ".tmp";
                     copyFileRecursively(output, pivot, true);
@@ -1454,8 +1454,8 @@ void DerivationGoal::buildDone()
         registerOutputs();
 
         /* Delete unused redirected outputs (when doing hash rewriting). */
-        foreach (RedirectedOutputs::iterator, i, redirectedOutputs)
-            if (pathExists(i->second)) deletePath(i->second);
+        for (auto& i : redirectedOutputs)
+            if (pathExists(i.second)) deletePath(i.second);
 
         /* Delete the chroot (if we were using one). */
         autoDelChroot.reset(); /* this runs the destructor */
@@ -1516,8 +1516,8 @@ void DerivationGoal::buildDone()
                Hook errors (like communication problems with the
                remote machine) shouldn't be cached either. */
             if (settings.cacheFailure && !fixedOutput && !diskFull)
-                foreach (DerivationOutputs::iterator, i, drv.outputs)
-                    worker.store.registerFailedPath(i->second.path);
+                for (auto& i : drv.outputs)
+                    worker.store.registerFailedPath(i.second.path);
         }
 
         done(st, e.msg());
@@ -1554,7 +1554,7 @@ HookReply DerivationGoal::tryBuildHook()
        required from the build machine.  (The hook could parse the
        drv file itself, but this is easier.) */
     Strings features = tokenizeString<Strings>(get(drv.env, "requiredSystemFeatures"));
-    foreach (Strings::iterator, i, features) checkStoreName(*i); /* !!! abuse */
+    for (auto& i : features) checkStoreName(i); /* !!! abuse */
 
     /* Send the request to the hook. */
     writeLine(worker.hook->toAgent.writeSide, (format("%1% %2% %3% %4%")
@@ -1596,13 +1596,13 @@ HookReply DerivationGoal::tryBuildHook()
     computeFSClosure(worker.store, drvPath, allInputs);
 
     string s;
-    foreach (PathSet::iterator, i, allInputs) { s += *i; s += ' '; }
+    for (auto& i : allInputs) { s += i; s += ' '; }
     writeLine(hook->toAgent.writeSide, s);
 
     /* Tell the hooks the missing outputs that have to be copied back
        from the remote system. */
     s = "";
-    foreach (PathSet::iterator, i, missingPaths) { s += *i; s += ' '; }
+    for (auto& i : missingPaths) { s += i; s += ' '; }
     writeLine(hook->toAgent.writeSide, s);
 
     hook->toAgent.writeSide.close();
@@ -1698,8 +1698,8 @@ void DerivationGoal::startBuilder()
     env["NIX_BUILD_CORES"] = (format("%d") % settings.buildCores).str();
 
     /* Add all bindings specified in the derivation. */
-    foreach (StringPairs::iterator, i, drv.env)
-        env[i->first] = i->second;
+    for (auto& i : drv.env)
+        env[i.first] = i.second;
 
     /* Create a temporary directory where the build will take
        place. */
@@ -1752,7 +1752,7 @@ void DerivationGoal::startBuilder()
        already know the cryptographic hash of the output). */
     if (fixedOutput) {
         Strings varNames = tokenizeString<Strings>(get(drv.env, "impureEnvVars"));
-        foreach (Strings::iterator, i, varNames) env[*i] = getEnv(*i);
+        for (auto& i : varNames) env[i] = getEnv(i);
     }
 
     /* The `exportReferencesGraph' feature allows the references graph
@@ -1788,11 +1788,11 @@ void DerivationGoal::startBuilder()
         computeFSClosure(worker.store, storePath, paths);
         paths2 = paths;
 
-        foreach (PathSet::iterator, j, paths2) {
-            if (isDerivation(*j)) {
-                Derivation drv = derivationFromPath(worker.store, *j);
-                foreach (DerivationOutputs::iterator, k, drv.outputs)
-                    computeFSClosure(worker.store, k->second.path, paths);
+        for (auto& j : paths2) {
+            if (isDerivation(j)) {
+                Derivation drv = derivationFromPath(worker.store, j);
+                for (auto& k : drv.outputs)
+                    computeFSClosure(worker.store, k.second.path, paths);
             }
         }
 
@@ -1896,10 +1896,10 @@ void DerivationGoal::startBuilder()
         /* Make the closure of the inputs available in the chroot, rather than
            the whole store.  This prevents any access to undeclared
            dependencies. */
-        foreach (PathSet::iterator, i, inputPaths) {
+        for (auto& i : inputPaths) {
             struct stat st;
-            if (lstat(i->c_str(), &st))
-                throw SysError(format("getting attributes of path `%1%'") % *i);
+            if (lstat(i.c_str(), &st))
+                throw SysError(format("getting attributes of path `%1%'") % i);
 
             if (S_ISLNK(st.st_mode)) {
                 /* Since bind-mounts follow symlinks, thus representing their
@@ -1907,12 +1907,12 @@ void DerivationGoal::startBuilder()
                    symlinks. XXX: When running unprivileged, TARGET can be
                    deleted by the build process.  Use 'open_tree' & co. when
                    it's more widely available.  */
-                Path target = chrootRootDir + *i;
-                if (symlink(readLink(*i).c_str(), target.c_str()) == -1)
-                    throw SysError(format("failed to create symlink '%1%' to '%2%'") % target % readLink(*i));
+                Path target = chrootRootDir + i;
+                if (symlink(readLink(i).c_str(), target.c_str()) == -1)
+                    throw SysError(format("failed to create symlink '%1%' to '%2%'") % target % readLink(i));
             }
             else
-                dirsInChroot[*i] = *i;
+                dirsInChroot[i] = i;
         }
 
         /* If we're repairing, checking or rebuilding part of a
@@ -1943,16 +1943,16 @@ void DerivationGoal::startBuilder()
            contents of the new outputs to replace the dummy strings
            with the actual hashes. */
         if (validPaths.size() > 0)
-            foreach (PathSet::iterator, i, validPaths)
-                addHashRewrite(*i);
+            for (auto i : validPaths)
+                addHashRewrite(i);
 
         /* If we're repairing, then we don't want to delete the
            corrupt outputs in advance.  So rewrite them as well. */
         if (buildMode == bmRepair)
-            foreach (PathSet::iterator, i, missingPaths)
-                if (worker.store.isValidPath(*i) && pathExists(*i)) {
-                    addHashRewrite(*i);
-                    redirectedBadOutputs.insert(*i);
+            for (auto& i : missingPaths)
+                if (worker.store.isValidPath(i) && pathExists(i)) {
+                    addHashRewrite(i);
+                    redirectedBadOutputs.insert(i);
                 }
     }
 
@@ -2186,10 +2186,10 @@ void DerivationGoal::runChild()
             /* Bind-mount all the directories from the "host"
                filesystem that we want in the chroot
                environment. */
-            foreach (DirsInChroot::iterator, i, dirsInChroot) {
+            for (auto& i : dirsInChroot) {
                 struct stat st;
-                Path source = i->second;
-                Path target = chrootRootDir + i->first;
+                Path source = i.second;
+                Path target = chrootRootDir + i.first;
                 if (source == "/proc") continue; // backwards compatibility
                 if (stat(source.c_str(), &st) == -1)
                     throw SysError(format("getting attributes of path `%1%'") % source);
@@ -2340,8 +2340,8 @@ void DerivationGoal::runChild()
 
         /* Fill in the environment. */
         Strings envStrs;
-        foreach (Environment::const_iterator, i, env)
-            envStrs.push_back(rewriteHashes(i->first + "=" + i->second, rewritesToTmp));
+        for (const auto& i : env)
+            envStrs.push_back(rewriteHashes(i.first + "=" + i.second, rewritesToTmp));
 
         /* If we are running in `build-users' mode, then switch to the
            user we allocated above.  Make sure that we drop all root
@@ -2420,8 +2420,8 @@ void DerivationGoal::runChild()
         /* Fill in the arguments. */
         Strings args;
         args.push_back(builderBasename);
-        foreach (Strings::iterator, i, drv.args)
-            args.push_back(rewriteHashes(*i, rewritesToTmp));
+        for (auto& i : drv.args)
+            args.push_back(rewriteHashes(i, rewritesToTmp));
 
         /* If DRV targets the same operating system kernel, try to execute it:
            there might be binfmt_misc set up for user-land emulation of other
@@ -2468,14 +2468,14 @@ PathSet parseReferenceSpecifiers(const Derivation & drv, string attr)
 {
     PathSet result;
     Paths paths = tokenizeString<Paths>(attr);
-    foreach (Strings::iterator, i, paths) {
-        if (isStorePath(*i))
-            result.insert(*i);
-        else if (drv.outputs.find(*i) != drv.outputs.end())
-            result.insert(drv.outputs.find(*i)->second.path);
+    for (auto& i : paths) {
+        if (isStorePath(i))
+            result.insert(i);
+        else if (drv.outputs.find(i) != drv.outputs.end())
+            result.insert(drv.outputs.find(i)->second.path);
         else throw BuildError(
             format("derivation contains an invalid reference specifier `%1%'")
-            % *i);
+            % i);
     }
     return result;
 }
@@ -2488,8 +2488,8 @@ void DerivationGoal::registerOutputs()
        to do anything here. */
     if (hook) {
         bool allValid = true;
-        foreach (DerivationOutputs::iterator, i, drv.outputs)
-            if (!worker.store.isValidPath(i->second.path)) allValid = false;
+        for (auto& i : drv.outputs)
+            if (!worker.store.isValidPath(i.second.path)) allValid = false;
         if (allValid) return;
     }
 
@@ -2505,8 +2505,8 @@ void DerivationGoal::registerOutputs()
     /* Check whether the output paths were created, and grep each
        output path to determine what other paths it references.  Also make all
        output paths read-only. */
-    foreach (DerivationOutputs::iterator, i, drv.outputs) {
-        Path path = i->second.path;
+    for (auto& i : drv.outputs) {
+        Path path = i.second.path;
         if (missingPaths.find(path) == missingPaths.end()) continue;
 
         Path actualPath = path;
@@ -2568,10 +2568,10 @@ void DerivationGoal::registerOutputs()
         /* Check that fixed-output derivations produced the right
            outputs (i.e., the content hash should match the specified
            hash). */
-        if (i->second.hash != "") {
+        if (i.second.hash != "") {
 
             bool recursive; HashType ht; Hash h;
-            i->second.parseHashInfo(recursive, ht, h);
+            i.second.parseHashInfo(recursive, ht, h);
 
             if (!recursive) {
                 /* The output path should be a regular file without
@@ -2586,7 +2586,7 @@ void DerivationGoal::registerOutputs()
             if (h != h2) {
                 if (settings.printBuildTrace)
                     printMsg(lvlError, format("@ hash-mismatch %1% %2% %3% %4%")
-                             % path % i->second.hashAlgo
+                             % path % i.second.hashAlgo
                              % printHash16or32(h) % printHash16or32(h2));
                 throw BuildError(format("hash mismatch for store item '%1%'") % path);
             }
@@ -2650,12 +2650,12 @@ void DerivationGoal::registerOutputs()
 
         /* For debugging, print out the referenced and unreferenced
            paths. */
-        foreach (PathSet::iterator, i, inputPaths) {
-            PathSet::iterator j = references.find(*i);
+        for (auto& i : inputPaths) {
+            PathSet::iterator j = references.find(i);
             if (j == references.end())
-                debug(format("unreferenced input: `%1%'") % *i);
+                debug(format("unreferenced input: `%1%'") % i);
             else
-                debug(format("referenced input: `%1%'") % *i);
+                debug(format("referenced input: `%1%'") % i);
         }
 
         /* Enforce `allowedReferences' and friends. */
@@ -2985,12 +2985,12 @@ void DerivationGoal::handleEOF(int fd)
 PathSet DerivationGoal::checkPathValidity(bool returnValid, bool checkHash)
 {
     PathSet result;
-    foreach (DerivationOutputs::iterator, i, drv.outputs) {
-        if (!wantOutput(i->first, wantedOutputs)) continue;
+    for (auto& i : drv.outputs) {
+        if (!wantOutput(i.first, wantedOutputs)) continue;
         bool good =
-            worker.store.isValidPath(i->second.path) &&
-            (!checkHash || worker.store.pathContentsGood(i->second.path));
-        if (good == returnValid) result.insert(i->second.path);
+            worker.store.isValidPath(i.second.path) &&
+            (!checkHash || worker.store.pathContentsGood(i.second.path));
+        if (good == returnValid) result.insert(i.second.path);
     }
     return result;
 }
@@ -3186,9 +3186,9 @@ void SubstitutionGoal::tryNext()
 
     /* To maintain the closure invariant, we first have to realise the
        paths referenced by this one. */
-    foreach (PathSet::iterator, i, info.references)
-        if (*i != storePath) /* ignore self-references */
-            addWaitee(worker.makeSubstitutionGoal(*i));
+    for (auto& i : info.references)
+        if (i != storePath) /* ignore self-references */
+            addWaitee(worker.makeSubstitutionGoal(i));
 
     if (waitees.empty()) /* to prevent hang (no wake-up event) */
         referencesValid();
@@ -3207,9 +3207,9 @@ void SubstitutionGoal::referencesValid()
         return;
     }
 
-    foreach (PathSet::iterator, i, info.references)
-        if (*i != storePath) /* ignore self-references */
-            assert(worker.store.isValidPath(*i));
+    for (auto& i : info.references)
+        if (i != storePath) /* ignore self-references */
+            assert(worker.store.isValidPath(i));
 
     state = &SubstitutionGoal::tryToRun;
     worker.wakeUp(shared_from_this());
@@ -3521,8 +3521,8 @@ void Worker::removeGoal(GoalPtr goal)
     }
 
     /* Wake up goals waiting for any goal to finish. */
-    foreach (WeakGoals::iterator, i, waitingForAnyGoal) {
-        GoalPtr goal = i->lock();
+    for (auto& i : waitingForAnyGoal) {
+        GoalPtr goal = i.lock();
         if (goal) wakeUp(goal);
     }
 
@@ -3575,8 +3575,8 @@ void Worker::childTerminated(pid_t pid, bool wakeSleepers)
     if (wakeSleepers) {
 
         /* Wake up goals waiting for a build slot. */
-        foreach (WeakGoals::iterator, i, wantingToBuild) {
-            GoalPtr goal = i->lock();
+        for (auto& i : wantingToBuild) {
+            GoalPtr goal = i.lock();
             if (goal) wakeUp(goal);
         }
 
@@ -3611,7 +3611,7 @@ void Worker::waitForAWhile(GoalPtr goal)
 
 void Worker::run(const Goals & _topGoals)
 {
-    foreach (Goals::iterator, i,  _topGoals) topGoals.insert(*i);
+    for (auto& i :  _topGoals) topGoals.insert(i);
 
     startNest(nest, lvlDebug, format("entered goal loop"));
 
@@ -3677,12 +3677,12 @@ void Worker::waitForInput()
        deadline for any child. */
     assert(sizeof(time_t) >= sizeof(long));
     time_t nearest = LONG_MAX; // nearest deadline
-    foreach (Children::iterator, i, children) {
-        if (!i->second.respectTimeouts) continue;
+    for (auto& i : children) {
+        if (!i.second.respectTimeouts) continue;
         if (settings.maxSilentTime != 0)
-            nearest = std::min(nearest, i->second.lastOutput + settings.maxSilentTime);
+            nearest = std::min(nearest, i.second.lastOutput + settings.maxSilentTime);
         if (settings.buildTimeout != 0)
-            nearest = std::min(nearest, i->second.timeStarted + settings.buildTimeout);
+            nearest = std::min(nearest, i.second.timeStarted + settings.buildTimeout);
     }
     if (nearest != LONG_MAX) {
         timeout.tv_sec = std::max((time_t) 1, nearest - before);
@@ -3707,10 +3707,10 @@ void Worker::waitForInput()
     fd_set fds;
     FD_ZERO(&fds);
     int fdMax = 0;
-    foreach (Children::iterator, i, children) {
-        foreach (set<int>::iterator, j, i->second.fds) {
-            FD_SET(*j, &fds);
-            if (*j >= fdMax) fdMax = *j + 1;
+    for (auto& i : children) {
+        for (auto& j : i.second.fds) {
+            FD_SET(j, &fds);
+            if (j >= fdMax) fdMax = j + 1;
         }
     }
 
@@ -3728,34 +3728,34 @@ void Worker::waitForInput()
        careful that we don't keep iterators alive across calls to
        timedOut(). */
     set<pid_t> pids;
-    foreach (Children::iterator, i, children) pids.insert(i->first);
+    for (auto& i : children) pids.insert(i.first);
 
-    foreach (set<pid_t>::iterator, i, pids) {
+    for (auto& i : pids) {
         checkInterrupt();
-        Children::iterator j = children.find(*i);
+        Children::iterator j = children.find(i);
         if (j == children.end()) continue; // child destroyed
         GoalPtr goal = j->second.goal.lock();
         assert(goal);
 
         set<int> fds2(j->second.fds);
-        foreach (set<int>::iterator, k, fds2) {
-            if (FD_ISSET(*k, &fds)) {
+        for (auto& k : fds2) {
+            if (FD_ISSET(k, &fds)) {
                 unsigned char buffer[4096];
-                ssize_t rd = read(*k, buffer, sizeof(buffer));
+                ssize_t rd = read(k, buffer, sizeof(buffer));
                 if (rd == -1) {
                     if (errno != EINTR)
                         throw SysError(format("reading from %1%")
                             % goal->getName());
                 } else if (rd == 0) {
                     debug(format("%1%: got EOF") % goal->getName());
-                    goal->handleEOF(*k);
-                    j->second.fds.erase(*k);
+                    goal->handleEOF(k);
+                    j->second.fds.erase(k);
                 } else {
                     printMsg(lvlVomit, format("%1%: read %2% bytes")
                         % goal->getName() % rd);
                     string data((char *) buffer, rd);
                     j->second.lastOutput = after;
-                    goal->handleChildOutput(*k, data);
+                    goal->handleChildOutput(k, data);
                 }
             }
         }
@@ -3785,8 +3785,8 @@ void Worker::waitForInput()
 
     if (!waitingForAWhile.empty() && lastWokenUp + settings.pollInterval <= after) {
         lastWokenUp = after;
-        foreach (WeakGoals::iterator, i, waitingForAWhile) {
-            GoalPtr goal = i->lock();
+        for (auto& i : waitingForAWhile) {
+            GoalPtr goal = i.lock();
             if (goal) wakeUp(goal);
         }
         waitingForAWhile.clear();
@@ -3811,22 +3811,22 @@ void LocalStore::buildPaths(const PathSet & drvPaths, BuildMode buildMode)
     Worker worker(*this);
 
     Goals goals;
-    foreach (PathSet::const_iterator, i, drvPaths) {
-        DrvPathWithOutputs i2 = parseDrvPathWithOutputs(*i);
+    for (auto& i : drvPaths) {
+        DrvPathWithOutputs i2 = parseDrvPathWithOutputs(i);
         if (isDerivation(i2.first))
             goals.insert(worker.makeDerivationGoal(i2.first, i2.second, buildMode));
         else
-            goals.insert(worker.makeSubstitutionGoal(*i, buildMode));
+            goals.insert(worker.makeSubstitutionGoal(i, buildMode));
     }
 
     worker.run(goals);
 
     PathSet failed;
-    foreach (Goals::iterator, i, goals)
-        if ((*i)->getExitCode() == Goal::ecFailed) {
-            DerivationGoal * i2 = dynamic_cast<DerivationGoal *>(i->get());
+    for (auto& i : goals)
+        if (i->getExitCode() == Goal::ecFailed) {
+            DerivationGoal * i2 = dynamic_cast<DerivationGoal *>(i.get());
             if (i2) failed.insert(i2->getDrvPath());
-            else failed.insert(dynamic_cast<SubstitutionGoal *>(i->get())->getStorePath());
+            else failed.insert(dynamic_cast<SubstitutionGoal *>(i.get())->getStorePath());
         }
 
     if (!failed.empty())
diff --git a/nix/libstore/derivations.cc b/nix/libstore/derivations.cc
index d316f6c7bf1..0c3a249228d 100644
--- a/nix/libstore/derivations.cc
+++ b/nix/libstore/derivations.cc
@@ -31,8 +31,8 @@ Path writeDerivation(StoreAPI & store,
 {
     PathSet references;
     references.insert(drv.inputSrcs.begin(), drv.inputSrcs.end());
-    foreach (DerivationInputs::const_iterator, i, drv.inputDrvs)
-        references.insert(i->first);
+    for (const auto& i : drv.inputDrvs)
+        references.insert(i.first);
     /* 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). */
@@ -155,21 +155,21 @@ string unparseDerivation(const Derivation & drv)
     s += "Derive([";
 
     bool first = true;
-    foreach (DerivationOutputs::const_iterator, i, drv.outputs) {
+    for (const auto& i : drv.outputs) {
         if (first) first = false; else s += ',';
-        s += '('; printString(s, i->first);
-        s += ','; printString(s, i->second.path);
-        s += ','; printString(s, i->second.hashAlgo);
-        s += ','; printString(s, i->second.hash);
+        s += '('; printString(s, i.first);
+        s += ','; printString(s, i.second.path);
+        s += ','; printString(s, i.second.hashAlgo);
+        s += ','; printString(s, i.second.hash);
         s += ')';
     }
 
     s += "],[";
     first = true;
-    foreach (DerivationInputs::const_iterator, i, drv.inputDrvs) {
+    for (const auto& i : drv.inputDrvs) {
         if (first) first = false; else s += ',';
-        s += '('; printString(s, i->first);
-        s += ','; printStrings(s, i->second.begin(), i->second.end());
+        s += '('; printString(s, i.first);
+        s += ','; printStrings(s, i.second.begin(), i.second.end());
         s += ')';
     }
 
@@ -182,10 +182,10 @@ string unparseDerivation(const Derivation & drv)
 
     s += ",[";
     first = true;
-    foreach (StringPairs::const_iterator, i, drv.env) {
+    for (const auto& i : drv.env) {
         if (first) first = false; else s += ',';
-        s += '('; printString(s, i->first);
-        s += ','; printString(s, i->second);
+        s += '('; printString(s, i.first);
+        s += ','; printString(s, i.second);
         s += ')';
     }
 
@@ -246,15 +246,15 @@ Hash hashDerivationModulo(StoreAPI & store, Derivation drv)
     /* For other derivations, replace the inputs paths with recursive
        calls to this function.*/
     DerivationInputs inputs2;
-    foreach (DerivationInputs::const_iterator, i, drv.inputDrvs) {
-        Hash h = drvHashes[i->first];
+    for (const auto& i : drv.inputDrvs) {
+        Hash h = drvHashes[i.first];
         if (h.type == htUnknown) {
-            assert(store.isValidPath(i->first));
-            Derivation drv2 = readDerivation(i->first);
+            assert(store.isValidPath(i.first));
+            Derivation drv2 = readDerivation(i.first);
             h = hashDerivationModulo(store, drv2);
-            drvHashes[i->first] = h;
+            drvHashes[i.first] = h;
         }
-        inputs2[printHash(h)] = i->second;
+        inputs2[printHash(h)] = i.second;
     }
     drv.inputDrvs = inputs2;
 
diff --git a/nix/libstore/gc.cc b/nix/libstore/gc.cc
index 261ea79ab32..1766a684122 100644
--- a/nix/libstore/gc.cc
+++ b/nix/libstore/gc.cc
@@ -349,9 +349,9 @@ static void addAdditionalRoots(StoreAPI & store, PathSet & roots)
 
     StringSet paths = tokenizeString<StringSet>(result, "\n");
 
-    foreach (StringSet::iterator, i, paths) {
-        if (isInStore(*i)) {
-            Path path = toStorePath(*i);
+    for (auto i : paths) {
+        if (isInStore(i)) {
+            Path path = toStorePath(i);
             if (roots.find(path) == roots.end() && store.isValidPath(path)) {
                 debug(format("got additional root `%1%'") % path);
                 roots.insert(path);
@@ -414,8 +414,8 @@ void LocalStore::deletePathRecursive(GCState & state, const Path & path)
     if (isValidPath(path)) {
         PathSet referrers;
         queryReferrers(path, referrers);
-        foreach (PathSet::iterator, i, referrers)
-            if (*i != path) deletePathRecursive(state, *i);
+        for (auto& i : referrers)
+            if (i != path) deletePathRecursive(state, i);
         size = queryPathInfo(path).narSize;
         invalidatePathChecked(path);
     }
@@ -505,22 +505,22 @@ bool LocalStore::canReachRoot(GCState & state, PathSet & visited, const Path & p
        don't delete the derivation if any of the outputs are alive. */
     if (state.gcKeepDerivations && isDerivation(path)) {
         PathSet outputs = queryDerivationOutputs(path);
-        foreach (PathSet::iterator, i, outputs)
-            if (isValidPath(*i) && queryDeriver(*i) == path)
-                incoming.insert(*i);
+        for (auto& i : outputs)
+            if (isValidPath(i) && queryDeriver(i) == path)
+                incoming.insert(i);
     }
 
     /* If gc-keep-outputs is set, then don't delete this path if there
        are derivers of this path that are not garbage. */
     if (state.gcKeepOutputs) {
         PathSet derivers = queryValidDerivers(path);
-        foreach (PathSet::iterator, i, derivers)
-            incoming.insert(*i);
+        for (auto& i : derivers)
+            incoming.insert(i);
     }
 
-    foreach (PathSet::iterator, i, incoming)
-        if (*i != path)
-            if (canReachRoot(state, visited, *i)) {
+    for (auto& i : incoming)
+        if (i != path)
+            if (canReachRoot(state, visited, i)) {
                 state.alive.insert(path);
                 return true;
             }
@@ -664,7 +664,7 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
     printMsg(lvlError, format("finding garbage collector roots..."));
     Roots rootMap = options.ignoreLiveness ? Roots() : findRoots();
 
-    foreach (Roots::iterator, i, rootMap) state.roots.insert(i->second);
+    for (auto& i : rootMap) state.roots.insert(i.second);
 
     /* Add additional roots returned by 'guix gc --list-busy'.  This is
        typically used to add running programs to the set of roots (to prevent
@@ -700,11 +700,11 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
 
     if (options.action == GCOptions::gcDeleteSpecific) {
 
-        foreach (PathSet::iterator, i, options.pathsToDelete) {
-            assertStorePath(*i);
-            tryToDelete(state, *i);
-            if (state.dead.find(*i) == state.dead.end())
-                throw Error(format("cannot delete path `%1%' since it is still alive") % *i);
+        for (auto& i : options.pathsToDelete) {
+            assertStorePath(i);
+            tryToDelete(state, i);
+            if (state.dead.find(i) == state.dead.end())
+                throw Error(format("cannot delete path `%1%' since it is still alive") % i);
         }
 
     } else if (options.maxFreed > 0) {
@@ -750,8 +750,8 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
             std::default_random_engine generator(seeder());
             std::shuffle(entries_.begin(), entries_.end(), generator);
 
-            foreach (vector<Path>::iterator, i, entries_)
-                tryToDelete(state, *i);
+            for (auto& i : entries_)
+                tryToDelete(state, i);
 
         } catch (GCLimitReached & e) {
         }
diff --git a/nix/libstore/globals.cc b/nix/libstore/globals.cc
index 89add1f107e..10c60f6106d 100644
--- a/nix/libstore/globals.cc
+++ b/nix/libstore/globals.cc
@@ -188,12 +188,12 @@ template<class N> void Settings::_get(N & res, const string & name)
 string Settings::pack()
 {
     string s;
-    foreach (SettingsMap::iterator, i, settings) {
-        if (i->first.find('\n') != string::npos ||
-            i->first.find('=') != string::npos ||
-            i->second.find('\n') != string::npos)
+    for (auto& i : settings) {
+        if (i.first.find('\n') != string::npos ||
+            i.first.find('=') != string::npos ||
+            i.second.find('\n') != string::npos)
             throw Error("invalid option name/value");
-        s += i->first; s += '='; s += i->second; s += '\n';
+        s += i.first; s += '='; s += i.second; s += '\n';
     }
     return s;
 }
diff --git a/nix/libstore/local-store.cc b/nix/libstore/local-store.cc
index d544253add8..50ef707fdf3 100644
--- a/nix/libstore/local-store.cc
+++ b/nix/libstore/local-store.cc
@@ -474,19 +474,19 @@ void LocalStore::checkDerivationOutputs(const Path & drvPath, const Derivation &
 
     else {
         Derivation drvCopy(drv);
-        foreach (DerivationOutputs::iterator, i, drvCopy.outputs) {
-            i->second.path = "";
-            drvCopy.env[i->first] = "";
+        for (auto& i : drvCopy.outputs) {
+            i.second.path = "";
+            drvCopy.env[i.first] = "";
         }
 
         Hash h = hashDerivationModulo(*this, drvCopy);
 
-        foreach (DerivationOutputs::const_iterator, i, drv.outputs) {
-            Path outPath = makeOutputPath(i->first, h, drvName);
-            StringPairs::const_iterator j = drv.env.find(i->first);
-            if (i->second.path != outPath || j == drv.env.end() || j->second != outPath)
+        for (const auto& i : drv.outputs) {
+            Path outPath = makeOutputPath(i.first, h, drvName);
+            StringPairs::const_iterator j = drv.env.find(i.first);
+            if (i.second.path != outPath || j == drv.env.end() || j->second != outPath)
                 throw Error(format("derivation `%1%' has incorrect output `%2%', should be `%3%'")
-                    % drvPath % i->second.path % outPath);
+                    % drvPath % i.second.path % outPath);
         }
     }
 }
@@ -670,8 +670,8 @@ PathSet LocalStore::queryValidPaths(const PathSet & paths)
 {
     return retrySQLite<PathSet>([&]() {
         PathSet res;
-        foreach (PathSet::const_iterator, i, paths)
-            if (isValidPath_(*i)) res.insert(*i);
+        for (const auto& i : paths)
+            if (isValidPath_(i)) res.insert(i);
         return res;
     });
 }
@@ -854,8 +854,8 @@ PathSet LocalStore::querySubstitutablePaths(const PathSet & paths)
     Agent & run = *substituter();
 
     string s = "have ";
-    foreach (PathSet::const_iterator, j, paths)
-        if (res.find(*j) == res.end()) { s += *j; s += " "; }
+    for (const auto& j : paths)
+        if (res.find(j) == res.end()) { s += j; s += " "; }
     writeLine(run.toAgent.writeSide, s);
     while (true) {
         /* FIXME: we only read stderr when an error occurs, so
@@ -889,8 +889,8 @@ void LocalStore::querySubstitutablePathInfos(PathSet & paths, SubstitutablePathI
     Agent & run = *substituter();
 
     string s = "info ";
-    foreach (PathSet::const_iterator, i, paths)
-        if (infos.find(*i) == infos.end()) { s += *i; s += " "; }
+    for (const auto& i : paths)
+        if (infos.find(i) == infos.end()) { s += i; s += " "; }
     writeLine(run.toAgent.writeSide, s);
 
     while (true) {
@@ -949,13 +949,13 @@ void LocalStore::registerValidPaths(const ValidPathInfos & infos)
         SQLiteTxn txn(db);
         PathSet paths;
 
-        foreach (ValidPathInfos::const_iterator, i, infos) {
-            assert(i->hash.type == htSHA256);
-            if (isValidPath_(i->path))
-                updatePathInfo(*i);
+        for (const auto& i : infos) {
+            assert(i.hash.type == htSHA256);
+            if (isValidPath_(i.path))
+                updatePathInfo(i);
             else
-                addValidPath(*i, false);
-            paths.insert(i->path);
+                addValidPath(i, false);
+            paths.insert(i.path);
         }
 
         for (auto & i : infos) {
@@ -967,12 +967,12 @@ void LocalStore::registerValidPaths(const ValidPathInfos & infos)
         /* Check that the derivation outputs are correct.  We can't do
            this in addValidPath() above, because the references might
            not be valid yet. */
-        foreach (ValidPathInfos::const_iterator, i, infos)
-            if (isDerivation(i->path)) {
+        for (const auto& i : infos)
+            if (isDerivation(i.path)) {
                 // FIXME: inefficient; we already loaded the
                 // derivation in addValidPath().
-                Derivation drv = readDerivation(i->path);
-                checkDerivationOutputs(i->path, drv);
+                Derivation drv = readDerivation(i.path);
+                checkDerivationOutputs(i.path, drv);
             }
 
         /* Do a topological sort of the paths.  This will throw an
@@ -1465,8 +1465,8 @@ bool LocalStore::verifyStore(bool checkContents, bool repair)
 
     PathSet validPaths2 = queryAllValidPaths(), validPaths, done;
 
-    foreach (PathSet::iterator, i, validPaths2)
-        verifyPath(*i, store, done, validPaths, repair, errors);
+    for (auto& i : validPaths2)
+        verifyPath(i, store, done, validPaths, repair, errors);
 
     /* Release the GC lock so that checking content hashes (which can
        take ages) doesn't block the GC or builds. */
@@ -1478,33 +1478,33 @@ bool LocalStore::verifyStore(bool checkContents, bool repair)
 
         Hash nullHash(htSHA256);
 
-        foreach (PathSet::iterator, i, validPaths) {
+        for (auto& i : validPaths) {
             try {
-                ValidPathInfo info = queryPathInfo(*i);
+                ValidPathInfo info = queryPathInfo(i);
 
                 /* Check the content hash (optionally - slow). */
-                printMsg(lvlTalkative, format("checking contents of `%1%'") % *i);
-                HashResult current = hashPath(info.hash.type, *i);
+                printMsg(lvlTalkative, format("checking contents of `%1%'") % i);
+                HashResult current = hashPath(info.hash.type, i);
 
                 if (info.hash != nullHash && info.hash != current.first) {
                     printMsg(lvlError, format("path `%1%' was modified! "
                             "expected hash `%2%', got `%3%'")
-                        % *i % printHash(info.hash) % printHash(current.first));
-                    if (repair) repairPath(*i); else errors = true;
+                        % i % printHash(info.hash) % printHash(current.first));
+                    if (repair) repairPath(i); else errors = true;
                 } else {
 
                     bool update = false;
 
                     /* Fill in missing hashes. */
                     if (info.hash == nullHash) {
-                        printMsg(lvlError, format("fixing missing hash on `%1%'") % *i);
+                        printMsg(lvlError, format("fixing missing hash on `%1%'") % i);
                         info.hash = current.first;
                         update = true;
                     }
 
                     /* Fill in missing narSize fields (from old stores). */
                     if (info.narSize == 0) {
-                        printMsg(lvlError, format("updating size field on `%1%' to %2%") % *i % current.second);
+                        printMsg(lvlError, format("updating size field on `%1%' to %2%") % i % current.second);
                         info.narSize = current.second;
                         update = true;
                     }
@@ -1516,7 +1516,7 @@ bool LocalStore::verifyStore(bool checkContents, bool repair)
             } catch (Error & e) {
                 /* It's possible that the path got GC'ed, so ignore
                    errors on invalid paths. */
-                if (isValidPath(*i))
+                if (isValidPath(i))
                     printMsg(lvlError, format("error: %1%") % e.msg());
                 else
                     printMsg(lvlError, format("warning: %1%") % e.msg());
@@ -1548,10 +1548,10 @@ void LocalStore::verifyPath(const Path & path, const PathSet & store,
            first, then we can invalidate this path as well. */
         bool canInvalidate = true;
         PathSet referrers; queryReferrers(path, referrers);
-        foreach (PathSet::iterator, i, referrers)
-            if (*i != path) {
-                verifyPath(*i, store, done, validPaths, repair, errors);
-                if (validPaths.find(*i) != validPaths.end())
+        for (auto& i : referrers)
+            if (i != path) {
+                verifyPath(i, store, done, validPaths, repair, errors);
+                if (validPaths.find(i) != validPaths.end())
                     canInvalidate = false;
             }
 
diff --git a/nix/libstore/misc.cc b/nix/libstore/misc.cc
index d4e6d1b4afc..bc5dec88bf2 100644
--- a/nix/libstore/misc.cc
+++ b/nix/libstore/misc.cc
@@ -28,15 +28,15 @@ void computeFSClosure(StoreAPI & store, const Path & path,
 
         if (includeOutputs) {
             PathSet derivers = store.queryValidDerivers(path);
-            foreach (PathSet::iterator, i, derivers)
-                edges.insert(*i);
+            for (auto& i : derivers)
+                edges.insert(i);
         }
 
         if (includeDerivers && isDerivation(path)) {
             PathSet outputs = store.queryDerivationOutputs(path);
-            foreach (PathSet::iterator, i, outputs)
-                if (store.isValidPath(*i) && store.queryDeriver(*i) == path)
-                    edges.insert(*i);
+            for (auto& i : outputs)
+                if (store.isValidPath(i) && store.queryDeriver(i) == path)
+                    edges.insert(i);
         }
 
     } else {
@@ -44,8 +44,8 @@ void computeFSClosure(StoreAPI & store, const Path & path,
 
         if (includeOutputs && isDerivation(path)) {
             PathSet outputs = store.queryDerivationOutputs(path);
-            foreach (PathSet::iterator, i, outputs)
-                if (store.isValidPath(*i)) edges.insert(*i);
+            for (auto& i : outputs)
+                if (store.isValidPath(i)) edges.insert(i);
         }
 
         if (includeDerivers) {
@@ -54,8 +54,8 @@ void computeFSClosure(StoreAPI & store, const Path & path,
         }
     }
 
-    foreach (PathSet::iterator, i, edges)
-        computeFSClosure(store, *i, paths, flipDirection, includeOutputs, includeDerivers);
+    for (auto& i : edges)
+        computeFSClosure(store, i, paths, flipDirection, includeOutputs, includeDerivers);
 }
 
 
@@ -74,11 +74,11 @@ static void dfsVisit(StoreAPI & store, const PathSet & paths,
     if (store.isValidPath(path))
         store.queryReferences(path, references);
 
-    foreach (PathSet::iterator, i, references)
+    for (auto& i : references)
         /* Don't traverse into paths that don't exist.  That can
            happen due to substitutes for non-existent paths. */
-        if (*i != path && paths.find(*i) != paths.end())
-            dfsVisit(store, paths, *i, visited, sorted, parents);
+        if (i != path && paths.find(i) != paths.end())
+            dfsVisit(store, paths, i, visited, sorted, parents);
 
     sorted.push_front(path);
     parents.erase(path);
@@ -89,8 +89,8 @@ Paths topoSortPaths(StoreAPI & store, const PathSet & paths)
 {
     Paths sorted;
     PathSet visited, parents;
-    foreach (PathSet::const_iterator, i, paths)
-        dfsVisit(store, paths, *i, visited, sorted, parents);
+    for (const auto& i : paths)
+        dfsVisit(store, paths, i, visited, sorted, parents);
     return sorted;
 }
 
diff --git a/nix/libstore/optimise-store.cc b/nix/libstore/optimise-store.cc
index 9fd6f3cb356..8d5bf28da9d 100644
--- a/nix/libstore/optimise-store.cc
+++ b/nix/libstore/optimise-store.cc
@@ -103,8 +103,8 @@ void LocalStore::optimisePath_(OptimiseStats & stats, const Path & path, InodeHa
 
     if (S_ISDIR(st.st_mode)) {
         Strings names = readDirectoryIgnoringInodes(path, inodeHash);
-        foreach (Strings::iterator, i, names)
-            optimisePath_(stats, path + "/" + *i, inodeHash);
+        for (auto& i : names)
+            optimisePath_(stats, path + "/" + i, inodeHash);
         return;
     }
 
@@ -244,11 +244,11 @@ void LocalStore::optimiseStore(OptimiseStats & stats)
     PathSet paths = queryAllValidPaths();
     InodeHash inodeHash = loadInodeHash();
 
-    foreach (PathSet::iterator, i, paths) {
-        addTempRoot(*i);
-        if (!isValidPath(*i)) continue; /* path was GC'ed, probably */
-        startNest(nest, lvlChatty, format("hashing files in `%1%'") % *i);
-        optimisePath_(stats, *i, inodeHash);
+    for (auto& i : paths) {
+        addTempRoot(i);
+        if (!isValidPath(i)) continue; /* path was GC'ed, probably */
+        startNest(nest, lvlChatty, format("hashing files in `%1%'") % i);
+        optimisePath_(stats, i, inodeHash);
     }
 }
 
diff --git a/nix/libstore/pathlocks.cc b/nix/libstore/pathlocks.cc
index 9797ddd7abf..c07f047192c 100644
--- a/nix/libstore/pathlocks.cc
+++ b/nix/libstore/pathlocks.cc
@@ -60,7 +60,7 @@ bool lockFile(int fd, LockType lockType, bool wait)
         while (fcntl(fd, F_SETLK, &lock) != 0) {
             checkInterrupt();
             if (errno == EACCES || errno == EAGAIN) return false;
-            if (errno != EINTR) 
+            if (errno != EINTR)
                 throw SysError(format("acquiring/releasing lock"));
         }
     }
@@ -94,7 +94,7 @@ bool PathLocks::lockPaths(const PathSet & _paths,
     const string & waitMsg, bool wait)
 {
     assert(fds.empty());
-    
+
     /* Note that `fds' is built incrementally so that the destructor
        will only release those locks that we have already acquired. */
 
@@ -102,11 +102,11 @@ bool PathLocks::lockPaths(const PathSet & _paths,
        the same order, thus preventing deadlocks. */
     Paths paths(_paths.begin(), _paths.end());
     paths.sort();
-    
+
     /* Acquire the lock for each path. */
-    foreach (Paths::iterator, i, paths) {
+    for (auto& i : paths) {
         checkInterrupt();
-        Path path = *i;
+        Path path = i;
         Path lockPath = path + ".lock";
 
         debug(format("locking path `%1%'") % path);
@@ -115,7 +115,7 @@ bool PathLocks::lockPaths(const PathSet & _paths,
             throw Error("deadlock: trying to re-acquire self-held lock");
 
         AutoCloseFD fd;
-        
+
         while (1) {
 
             /* Open/create the lock file. */
@@ -172,15 +172,15 @@ PathLocks::~PathLocks()
 
 void PathLocks::unlock()
 {
-    foreach (list<FDPair>::iterator, i, fds) {
-        if (deletePaths) deleteLockFile(i->second, i->first);
+    for (auto& i : fds) {
+        if (deletePaths) deleteLockFile(i.second, i.first);
 
-        lockedPaths.erase(i->second);
-        if (close(i->first) == -1)
+        lockedPaths.erase(i.second);
+        if (close(i.first) == -1)
             printMsg(lvlError,
-                format("error (ignored): cannot close lock file on `%1%'") % i->second);
+                format("error (ignored): cannot close lock file on `%1%'") % i.second);
 
-        debug(format("lock released on `%1%'") % i->second);
+        debug(format("lock released on `%1%'") % i.second);
     }
 
     fds.clear();
@@ -199,5 +199,5 @@ bool pathIsLockedByMe(const Path & path)
     return lockedPaths.find(lockPath) != lockedPaths.end();
 }
 
- 
+
 }
diff --git a/nix/libstore/references.cc b/nix/libstore/references.cc
index 282b848938b..d9c8a9fbe38 100644
--- a/nix/libstore/references.cc
+++ b/nix/libstore/references.cc
@@ -13,7 +13,7 @@ namespace nix {
 static unsigned int refLength = 32; /* characters */
 
 
-static void search(const unsigned char * s, unsigned int len, 
+static void search(const unsigned char * s, unsigned int len,
     StringSet & hashes, StringSet & seen)
 {
     static bool initialised = false;
@@ -24,7 +24,7 @@ static void search(const unsigned char * s, unsigned int len,
             isBase32[(unsigned char) base32Chars[i]] = true;
         initialised = true;
     }
-    
+
     for (unsigned int i = 0; i + refLength <= len; ) {
         int j;
         bool match = true;
@@ -56,7 +56,7 @@ struct RefScanSink : Sink
     string tail;
 
     RefScanSink() : hashSink(htSHA256) { }
-    
+
     void operator () (const unsigned char * data, size_t len);
 };
 
@@ -89,17 +89,17 @@ PathSet scanForReferences(const string & path,
     /* 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'). */
-    foreach (PathSet::const_iterator, i, refs) {
-        string baseName = baseNameOf(*i);
+    for (const auto& i : refs) {
+        string baseName = baseNameOf(i);
         string::size_type pos = baseName.find('-');
         if (pos == string::npos)
-            throw Error(format("bad reference `%1%'") % *i);
+            throw Error(format("bad reference `%1%'") % i);
         string s = string(baseName, 0, pos);
         assert(s.size() == refLength);
         assert(backMap.find(s) == backMap.end());
         // parseHash(htSHA256, s);
         sink.hashes.insert(s);
-        backMap[s] = *i;
+        backMap[s] = i;
     }
 
     /* Look for the hashes in the NAR dump of the path. */
@@ -107,14 +107,14 @@ PathSet scanForReferences(const string & path,
 
     /* Map the hashes found back to their store paths. */
     PathSet found;
-    foreach (StringSet::iterator, i, sink.seen) {
+    for (auto& i : sink.seen) {
         std::map<string, Path>::iterator j;
-        if ((j = backMap.find(*i)) == backMap.end()) abort();
+        if ((j = backMap.find(i)) == backMap.end()) abort();
         found.insert(j->second);
     }
 
     hash = sink.hashSink.finish();
-        
+
     return found;
 }
 
diff --git a/nix/libstore/store-api.cc b/nix/libstore/store-api.cc
index 38a1403a712..7282188fb37 100644
--- a/nix/libstore/store-api.cc
+++ b/nix/libstore/store-api.cc
@@ -62,14 +62,14 @@ void checkStoreName(const string & name)
        reasons (e.g., "." and ".."). */
     if (string(name, 0, 1) == ".")
         throw Error(format("invalid name: `%1%' (can't begin with dot)") % name);
-    foreach (string::const_iterator, i, name)
-        if (!((*i >= 'A' && *i <= 'Z') ||
-              (*i >= 'a' && *i <= 'z') ||
-              (*i >= '0' && *i <= '9') ||
-              validChars.find(*i) != string::npos))
+    for (const auto& i : name)
+        if (!((i >= 'A' && i <= 'Z') ||
+              (i >= 'a' && i <= 'z') ||
+              (i >= '0' && i <= '9') ||
+              validChars.find(i) != string::npos))
         {
             throw Error(format("invalid character `%1%' in name `%2%'")
-                % *i % name);
+                % i % name);
         }
 }
 
@@ -81,22 +81,22 @@ void checkStoreName(const string & name)
    where
 
    <store> = the location of the store, usually /gnu/store
-   
+
    <name> = a human readable name for the path, typically obtained
      from the name attribute of the derivation, or the name of the
      source file from which the store path is created.  For derivation
      outputs other than the default "out" output, the string "-<id>"
      is suffixed to <name>.
-     
+
    <h> = base-32 representation of the first 160 bits of a SHA-256
      hash of <s>; the hash part of the store name
-     
+
    <s> = the string "<type>:sha256:<h2>:<store>:<name>";
      note that it includes the location of the store as well as the
      name to make sure that changes to either of those are reflected
      in the hash (e.g. you won't get /nix/store/<h>-name1 and
      /nix/store/<h>-name2 with equal hash parts).
-     
+
    <type> = one of:
      "text:<r1>:<r2>:...<rN>"
        for plain text files written to the store using
@@ -188,9 +188,9 @@ Path computeStorePathForText(const string & name, const string & s,
        hacky, but we can't put them in `s' since that would be
        ambiguous. */
     string type = "text";
-    foreach (PathSet::const_iterator, i, references) {
+    for (const auto& i : references) {
         type += ":";
-        type += *i;
+        type += i;
     }
     return makeStorePath(type, hash, name);
 }
@@ -203,11 +203,11 @@ string StoreAPI::makeValidityRegistration(const PathSet & paths,
     bool showDerivers, bool showHash)
 {
     string s = "";
-    
-    foreach (PathSet::iterator, i, paths) {
-        s += *i + "\n";
 
-        ValidPathInfo info = queryPathInfo(*i);
+    for (auto& i : paths) {
+        s += i + "\n";
+
+        ValidPathInfo info = queryPathInfo(i);
 
         if (showHash) {
             s += printHash(info.hash) + "\n";
@@ -219,8 +219,8 @@ string StoreAPI::makeValidityRegistration(const PathSet & paths,
 
         s += (format("%1%\n") % info.references.size()).str();
 
-        foreach (PathSet::iterator, j, info.references)
-            s += *j + "\n";
+        for (auto& j : info.references)
+            s += j + "\n";
     }
 
     return s;
@@ -229,9 +229,9 @@ string StoreAPI::makeValidityRegistration(const PathSet & paths,
 string showPaths(const PathSet & paths)
 {
     string s;
-    foreach (PathSet::const_iterator, i, paths) {
+    for (const auto& i : paths) {
         if (s.size() != 0) s += ", ";
-        s += "`" + *i + "'";
+        s += "`" + i + "'";
     }
     return s;
 }
@@ -247,7 +247,7 @@ Path readStorePath(Source & from)
 template<class T> T readStorePaths(Source & from)
 {
     T paths = readStrings<T>(from);
-    foreach (typename T::iterator, i, paths) assertStorePath(*i);
+    for (auto& i : paths) assertStorePath(i);
     return paths;
 }
 
diff --git a/nix/libutil/serialise.cc b/nix/libutil/serialise.cc
index 6f04ab15918..01aeea25c0c 100644
--- a/nix/libutil/serialise.cc
+++ b/nix/libutil/serialise.cc
@@ -188,8 +188,8 @@ void writeString(const string & s, Sink & sink)
 template<class T> void writeStrings(const T & ss, Sink & sink)
 {
     writeInt(ss.size(), sink);
-    foreach (typename T::const_iterator, i, ss)
-        writeString(*i, sink);
+    for (auto& i : ss)
+        writeString(i, sink);
 }
 
 template void writeStrings(const Paths & ss, Sink & sink);
diff --git a/nix/libutil/util.cc b/nix/libutil/util.cc
index 398f61841f1..74f7a97cc4f 100644
--- a/nix/libutil/util.cc
+++ b/nix/libutil/util.cc
@@ -1158,9 +1158,9 @@ template vector<string> tokenizeString(const string & s, const string & separato
 string concatStringsSep(const string & sep, const Strings & ss)
 {
     string s;
-    foreach (Strings::const_iterator, i, ss) {
+    for (const auto& i : ss) {
         if (s.size() != 0) s += sep;
-        s += *i;
+        s += i;
     }
     return s;
 }
@@ -1169,9 +1169,9 @@ string concatStringsSep(const string & sep, const Strings & ss)
 string concatStringsSep(const string & sep, const StringSet & ss)
 {
     string s;
-    foreach (StringSet::const_iterator, i, ss) {
+    for (const auto& i : ss) {
         if (s.size() != 0) s += sep;
-        s += *i;
+        s += i;
     }
     return s;
 }
diff --git a/nix/libutil/util.hh b/nix/libutil/util.hh
index 176247e699d..a07c3be6eb6 100644
--- a/nix/libutil/util.hh
+++ b/nix/libutil/util.hh
@@ -16,13 +16,6 @@
 namespace nix {
 
 
-#define foreach(it_type, it, collection)                                \
-    for (it_type it = (collection).begin(); it != (collection).end(); ++it)
-
-#define foreach_reverse(it_type, it, collection)                                \
-    for (it_type it = (collection).rbegin(); it != (collection).rend(); ++it)
-
-
 /* Return an environment variable. */
 string getEnv(const string & key, const string & def = "");
 
diff --git a/nix/nix-daemon/nix-daemon.cc b/nix/nix-daemon/nix-daemon.cc
index b43bcf7fc6e..9fff31a587c 100644
--- a/nix/nix-daemon/nix-daemon.cc
+++ b/nix/nix-daemon/nix-daemon.cc
@@ -679,12 +679,12 @@ static void performOp(bool trusted, unsigned int clientVersion,
         store->querySubstitutablePathInfos(paths, infos);
         stopWork();
         writeInt(infos.size(), to);
-        foreach (SubstitutablePathInfos::iterator, i, infos) {
-            writeString(i->first, to);
-            writeString(i->second.deriver, to);
-            writeStrings(i->second.references, to);
-            writeLongLong(i->second.downloadSize, to);
-            writeLongLong(i->second.narSize, to);
+        for (auto& i : infos) {
+            writeString(i.first, to);
+            writeString(i.second.deriver, to);
+            writeStrings(i.second.references, to);
+            writeLongLong(i.second.downloadSize, to);
+            writeLongLong(i.second.narSize, to);
         }
         break;
     }