7 files changed, 26 insertions, 23 deletions
diff --git a/third_party/nix/src/libutil/args.hh b/third_party/nix/src/libutil/args.hh
index 409ea80f2d45..3057f3d2ab46 100644
--- a/third_party/nix/src/libutil/args.hh
+++ b/third_party/nix/src/libutil/args.hh
@@ -212,7 +212,7 @@ Strings argvToStrings(int argc, char** argv);
 std::string renderLabels(const Strings& labels);
 
 /* Helper function for printing 2-column tables. */
-typedef std::vector<std::pair<std::string, std::string>> Table2;
+using Table2 = std::vector<std::pair<std::string, std::string> >;
 
 void printTable(std::ostream& out, const Table2& table);
 
diff --git a/third_party/nix/src/libutil/config.hh b/third_party/nix/src/libutil/config.hh
index 0441e3b9e848..027a6be2982a 100644
--- a/third_party/nix/src/libutil/config.hh
+++ b/third_party/nix/src/libutil/config.hh
@@ -203,7 +203,7 @@ class PathSetting : public BaseSetting<Path> {
 };
 
 struct GlobalConfig : public AbstractConfig {
-  typedef std::vector<Config*> ConfigRegistrations;
+  using ConfigRegistrations = std::vector<Config*>;
   static ConfigRegistrations* configRegistrations;
 
   bool set(const std::string& name, const std::string& value) override;
diff --git a/third_party/nix/src/libutil/istringstream_nocopy.hh b/third_party/nix/src/libutil/istringstream_nocopy.hh
index 997965630b6c..31683d37c91b 100644
--- a/third_party/nix/src/libutil/istringstream_nocopy.hh
+++ b/third_party/nix/src/libutil/istringstream_nocopy.hh
@@ -12,15 +12,15 @@ template <class CharT, class Traits = std::char_traits<CharT>,
           class Allocator = std::allocator<CharT>>
 class basic_istringbuf_nocopy : public std::basic_streambuf<CharT, Traits> {
  public:
-  typedef std::basic_string<CharT, Traits, Allocator> string_type;
+  using string_type = std::basic_string<CharT, Traits, Allocator>;
 
-  typedef typename std::basic_streambuf<CharT, Traits>::off_type off_type;
+  using off_type = typename std::basic_streambuf<CharT, Traits>::off_type;
 
-  typedef typename std::basic_streambuf<CharT, Traits>::pos_type pos_type;
+  using pos_type = typename std::basic_streambuf<CharT, Traits>::pos_type;
 
-  typedef typename std::basic_streambuf<CharT, Traits>::int_type int_type;
+  using int_type = typename std::basic_streambuf<CharT, Traits>::int_type;
 
-  typedef typename std::basic_streambuf<CharT, Traits>::traits_type traits_type;
+  using traits_type = typename std::basic_streambuf<CharT, Traits>::traits_type;
 
  private:
   const string_type& s;
@@ -28,7 +28,7 @@ class basic_istringbuf_nocopy : public std::basic_streambuf<CharT, Traits> {
   off_type off;
 
  public:
-  basic_istringbuf_nocopy(const string_type& s) : s{s}, off{0} {}
+  explicit basic_istringbuf_nocopy(const string_type& s) : s{s}, off{0} {}
 
  private:
   pos_type seekoff(off_type off, std::ios_base::seekdir dir,
@@ -49,20 +49,23 @@ class basic_istringbuf_nocopy : public std::basic_streambuf<CharT, Traits> {
   std::streamsize showmanyc() { return s.size() - off; }
 
   int_type underflow() {
-    if (typename string_type::size_type(off) == s.size())
+    if (typename string_type::size_type(off) == s.size()) {
       return traits_type::eof();
+    }
     return traits_type::to_int_type(s[off]);
   }
 
   int_type uflow() {
-    if (typename string_type::size_type(off) == s.size())
+    if (typename string_type::size_type(off) == s.size()) {
       return traits_type::eof();
+    }
     return traits_type::to_int_type(s[off++]);
   }
 
   int_type pbackfail(int_type ch) {
-    if (off == 0 || (ch != traits_type::eof() && ch != s[off - 1]))
+    if (off == 0 || (ch != traits_type::eof() && ch != s[off - 1])) {
       return traits_type::eof();
+    }
 
     return traits_type::to_int_type(s[--off]);
   }
@@ -71,12 +74,12 @@ class basic_istringbuf_nocopy : public std::basic_streambuf<CharT, Traits> {
 template <class CharT, class Traits = std::char_traits<CharT>,
           class Allocator = std::allocator<CharT>>
 class basic_istringstream_nocopy : public std::basic_iostream<CharT, Traits> {
-  typedef basic_istringbuf_nocopy<CharT, Traits, Allocator> buf_type;
+  using buf_type = basic_istringbuf_nocopy<CharT, Traits, Allocator>;
   buf_type buf;
 
  public:
-  basic_istringstream_nocopy(const typename buf_type::string_type& s)
+  explicit basic_istringstream_nocopy(const typename buf_type::string_type& s)
       : std::basic_iostream<CharT, Traits>(&buf), buf(s){};
 };
 
-typedef basic_istringstream_nocopy<char> istringstream_nocopy;
+using istringstream_nocopy = basic_istringstream_nocopy<char>;
diff --git a/third_party/nix/src/libutil/pool.hh b/third_party/nix/src/libutil/pool.hh
index fe6d5c28004e..56a579b269cd 100644
--- a/third_party/nix/src/libutil/pool.hh
+++ b/third_party/nix/src/libutil/pool.hh
@@ -36,7 +36,7 @@ class Pool {
 
   /* A function that checks whether an instance of R is still
      usable. Unusable instances are removed from the pool. */
-  typedef std::function<bool(const ref<R>&)> Validator;
+  using Validator = std::function<bool(const ref<R>&)>;
 
  private:
   Factory factory;
diff --git a/third_party/nix/src/libutil/serialise.hh b/third_party/nix/src/libutil/serialise.hh
index d088252fb69e..04f672781015 100644
--- a/third_party/nix/src/libutil/serialise.hh
+++ b/third_party/nix/src/libutil/serialise.hh
@@ -195,7 +195,7 @@ struct LambdaSink : Sink {
 
 /* Convert a function into a source. */
 struct LambdaSource : Source {
-  typedef std::function<size_t(unsigned char*, size_t)> lambda_t;
+  using lambda_t = std::function<size_t(unsigned char*, size_t)>;
 
   lambda_t lambda;
 
diff --git a/third_party/nix/src/libutil/types.hh b/third_party/nix/src/libutil/types.hh
index dae81fb94b6a..b8e7a3c9d5c7 100644
--- a/third_party/nix/src/libutil/types.hh
+++ b/third_party/nix/src/libutil/types.hh
@@ -107,12 +107,12 @@ class SysError : public Error {
 };
 
 typedef std::list<std::string> Strings;
-typedef std::set<std::string> StringSet;
-typedef std::map<std::string, std::string> StringMap;
+using StringSet = std::set<std::string>;
+using StringMap = std::map<std::string, std::string>;
 
 /* Paths are just strings. */
-typedef std::string Path;
-typedef std::list<Path> Paths;
-typedef std::set<Path> PathSet;
+using Path = std::string;
+using Paths = std::list<Path>;
+using PathSet = std::set<Path>;
 
 }  // namespace nix
diff --git a/third_party/nix/src/libutil/util.hh b/third_party/nix/src/libutil/util.hh
index d9fc1a27b134..9331fca7f30b 100644
--- a/third_party/nix/src/libutil/util.hh
+++ b/third_party/nix/src/libutil/util.hh
@@ -201,7 +201,7 @@ struct DIRDeleter {
   void operator()(DIR* dir) const { closedir(dir); }
 };
 
-typedef std::unique_ptr<DIR, DIRDeleter> AutoCloseDir;
+using AutoCloseDir = std::unique_ptr<DIR, DIRDeleter>;
 
 class Pid {
   pid_t pid = -1;
@@ -457,7 +457,7 @@ struct MaintainCount {
 std::pair<unsigned short, unsigned short> getWindowSize();
 
 /* Used in various places. */
-typedef std::function<bool(const Path& path)> PathFilter;
+using PathFilter = std::function<bool(const Path&)>;
 
 extern PathFilter defaultPathFilter;