diff --git a/src/nix-channel/nix-channel.cc b/src/nix-channel/nix-channel.cc
index ec9a7174e..c34f1d4b4 100755
--- a/src/nix-channel/nix-channel.cc
+++ b/src/nix-channel/nix-channel.cc
@@ -10,8 +10,8 @@ using namespace nix;
 
 typedef std::map<string,string> Channels;
 
-static auto channels = Channels{};
-static auto channelsList = Path{};
+static Channels channels;
+static Path channelsList;
 
 // Reads the list of channels.
 static void readChannels()
@@ -52,7 +52,7 @@ static void addChannel(const string & url, const string & name)
     writeChannels();
 }
 
-static auto profile = Path{};
+static Path profile;
 
 // Remove a channel.
 static void removeChannel(const string & name)
@@ -64,7 +64,7 @@ static void removeChannel(const string & name)
     runProgram(settings.nixBinDir + "/nix-env", true, { "--profile", profile, "--uninstall", name });
 }
 
-static auto nixDefExpr = Path{};
+static Path nixDefExpr;
 
 // Fetch Nix expressions and binary cache URLs from the subscribed channels.
 static void update(const StringSet & channelNames)
@@ -74,7 +74,7 @@ static void update(const StringSet & channelNames)
     auto store = openStore();
 
     // Download each channel.
-    auto exprs = Strings{};
+    Strings exprs;
     for (const auto & channel : channels) {
         auto name = channel.first;
         auto url = channel.second;
@@ -84,7 +84,7 @@ static void update(const StringSet & channelNames)
         // We want to download the url to a file to see if it's a tarball while also checking if we
         // got redirected in the process, so that we can grab the various parts of a nix channel
         // definition from a consistent location if the redirect changes mid-download.
-        auto effectiveUrl = string{};
+        std::string effectiveUrl;
         auto dl = getDownloader();
         auto filename = dl->downloadCached(store, url, false, "", Hash(), &effectiveUrl);
         url = chomp(std::move(effectiveUrl));
@@ -99,9 +99,9 @@ static void update(const StringSet & channelNames)
             cname = cname + (string) match[1];
         }
 
-        auto extraAttrs = string{};
+        std::string extraAttrs;
 
-        auto unpacked = false;
+        bool unpacked = false;
         if (std::regex_search(filename, std::regex("\\.tar\\.(gz|bz2|xz)$"))) {
             runProgram(settings.nixBinDir + "/nix-build", false, { "--no-out-link", "--expr", "import <nix/unpack-channel.nix> "
                         "{ name = \"" + cname + "\"; channelName = \"" + name + "\"; src = builtins.storePath \"" + filename + "\"; }" });
@@ -136,7 +136,7 @@ static void update(const StringSet & channelNames)
     // Unpack the channel tarballs into the Nix store and install them
     // into the channels profile.
     std::cerr << "unpacking channels...\n";
-    auto envArgs = Strings{ "--profile", profile, "--file", "<nix/unpack-channel.nix>", "--install", "--from-expression" };
+    Strings envArgs{ "--profile", profile, "--file", "<nix/unpack-channel.nix>", "--install", "--from-expression" };
     for (auto & expr : exprs)
         envArgs.push_back(std::move(expr));
     envArgs.push_back("--quiet");
@@ -173,12 +173,9 @@ int main(int argc, char ** argv)
         nixDefExpr = home + "/.nix-defexpr";
 
         // Figure out the name of the channels profile.
-        auto name = string{};
+        ;
         auto pw = getpwuid(getuid());
-        if (!pw)
-            name = getEnv("USER", "");
-        else
-            name = pw->pw_name;
+        std::string name = pw ? pw->pw_name : getEnv("USER", "");
         if (name.empty())
             throw Error("cannot figure out user name");
         profile = settings.nixStateDir + "/profiles/per-user/" + name + "/channels";
@@ -192,7 +189,7 @@ int main(int argc, char ** argv)
             cUpdate,
             cRollback
         } cmd = cNone;
-        auto args = std::vector<string>{};
+        std::vector<string> args;
         parseCmdLine(argc, argv, [&](Strings::iterator & arg, const Strings::iterator & end) {
             if (*arg == "--help") {
                 showManPage("nix-channel");
@@ -224,7 +221,7 @@ int main(int argc, char ** argv)
                     throw UsageError("'--add' requires one or two arguments");
                 {
                 auto url = args[0];
-                auto name = string{};
+                std::string name;
                 if (args.size() == 2) {
                     name = args[1];
                 } else {
@@ -253,7 +250,7 @@ int main(int argc, char ** argv)
             case cRollback:
                 if (args.size() > 1)
                     throw UsageError("'--rollback' has at most one argument");
-                auto envArgs = Strings{"--profile", profile};
+                Strings envArgs{"--profile", profile};
                 if (args.size() == 1) {
                     envArgs.push_back("--switch-generation");
                     envArgs.push_back(args[0]);