5 files changed, 18 insertions, 12 deletions
diff --git a/third_party/nix/src/libexpr/eval.cc b/third_party/nix/src/libexpr/eval.cc
index 3ecd990daaac..4064f1594f00 100644
--- a/third_party/nix/src/libexpr/eval.cc
+++ b/third_party/nix/src/libexpr/eval.cc
@@ -577,8 +577,8 @@ Value& mkString(Value& v, const std::string& s, const PathSet& context) {
   mkString(v, s.c_str());
   if (!context.empty()) {
     size_t n = 0;
-    v.string.context =
-        (const char**)allocBytes((context.size() + 1) * sizeof(char*));
+    v.string.context = static_cast<const char**>(
+        allocBytes((context.size() + 1) * sizeof(char*)));
     for (auto& i : context) {
       v.string.context[n++] = dupString(i.c_str());
     }
@@ -1703,7 +1703,8 @@ void EvalState::printStats() {
 
   struct rusage buf;
   getrusage(RUSAGE_SELF, &buf);
-  float cpuTime = buf.ru_utime.tv_sec + ((float)buf.ru_utime.tv_usec / 1000000);
+  float cpuTime = buf.ru_utime.tv_sec +
+                  (static_cast<float>(buf.ru_utime.tv_usec) / 1000000);
 
   uint64_t bEnvs = nrEnvs * sizeof(Env) + nrValuesInEnvs * sizeof(Value*);
   uint64_t bLists = nrListElems * sizeof(Value*);
diff --git a/third_party/nix/src/libexpr/nixexpr.cc b/third_party/nix/src/libexpr/nixexpr.cc
index 94e7d335cff0..24ce6ec3fc91 100644
--- a/third_party/nix/src/libexpr/nixexpr.cc
+++ b/third_party/nix/src/libexpr/nixexpr.cc
@@ -18,7 +18,7 @@ std::ostream& operator<<(std::ostream& str, const Expr& e) {
 
 static void showString(std::ostream& str, const std::string& s) {
   str << '"';
-  for (auto c : (std::string)s) {
+  for (auto c : std::string(s)) {
     if (c == '"' || c == '\\' || c == '$') {
       str << "\\" << c;
     } else if (c == '\n') {
@@ -191,7 +191,7 @@ std::ostream& operator<<(std::ostream& str, const Pos& pos) {
     str << "undefined position";
   } else {
     str << (format(ANSI_BOLD "%1%" ANSI_NORMAL ":%2%:%3%") %
-            (std::string)pos.file.value() % pos.line % pos.column)
+            std::string(pos.file.value()) % pos.line % pos.column)
                .str();
   }
   return str;
@@ -405,7 +405,7 @@ void ExprLambda::setName(Symbol& name) { this->name = name; }
 
 std::string ExprLambda::showNamePos() const {
   return (format("%1% at %2%") %
-          (name.has_value() ? "'" + (std::string)name.value() + "'"
+          (name.has_value() ? "'" + std::string(name.value()) + "'"
                             : "anonymous function") %
           pos)
       .str();
diff --git a/third_party/nix/src/libexpr/primops.cc b/third_party/nix/src/libexpr/primops.cc
index 04ccf7623b17..0008b7b180a9 100644
--- a/third_party/nix/src/libexpr/primops.cc
+++ b/third_party/nix/src/libexpr/primops.cc
@@ -876,7 +876,7 @@ 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) != std::string::npos) {
+  if (s.find(static_cast<char>(0)) != std::string::npos) {
     throw Error(format("the contents of the file '%1%' cannot be represented "
                        "as a Nix string") %
                 path);
@@ -1421,7 +1421,7 @@ static void prim_isList(EvalState& state, const Pos& pos, Value** args,
 static void elemAt(EvalState& state, const Pos& pos, Value& list, int n,
                    Value& v) {
   state.forceList(list, pos);
-  if (n < 0 || (unsigned int)n >= list.listSize()) {
+  if (n < 0 || static_cast<unsigned int>(n) >= list.listSize()) {
     throw Error(format("list index %1% is out of bounds, at %2%") % n % pos);
   }
   state.forceValue(*(*list.list)[n]);
@@ -1587,7 +1587,7 @@ static void prim_genList(EvalState& state, const Pos& pos, Value** args,
 
   state.mkList(v, len);
 
-  for (unsigned int n = 0; n < (unsigned int)len; ++n) {
+  for (unsigned int n = 0; n < static_cast<unsigned int>(len); ++n) {
     Value* arg = state.allocValue();
     mkInt(*arg, n);
     mkApp(*((*v.list)[n] = state.allocValue()), *args[0], *arg);
@@ -1790,7 +1790,10 @@ static void prim_substring(EvalState& state, const Pos& pos, Value** args,
                     pos);
   }
 
-  mkString(v, (unsigned int)start >= s.size() ? "" : std::string(s, start, len),
+  mkString(v,
+           static_cast<unsigned int>(start) >= s.size()
+               ? ""
+               : std::string(s, start, len),
            context);
 }
 
diff --git a/third_party/nix/src/libexpr/primops/fetchGit.cc b/third_party/nix/src/libexpr/primops/fetchGit.cc
index d0e0d389ccca..2b2ca476cbbb 100644
--- a/third_party/nix/src/libexpr/primops/fetchGit.cc
+++ b/third_party/nix/src/libexpr/primops/fetchGit.cc
@@ -129,7 +129,8 @@ GitInfo exportGit(ref<Store> store, const std::string& uri,
        git fetch to update the local ref to the remote ref. */
     struct stat st;
     doFetch = stat(localRefFile.c_str(), &st) != 0 ||
-              (uint64_t)st.st_mtime + settings.tarballTtl <= (uint64_t)now;
+              static_cast<uint64_t>(st.st_mtime) + settings.tarballTtl <=
+                  static_cast<uint64_t>(now);
   }
   if (doFetch) {
     DLOG(INFO) << "fetching Git repository '" << uri << "'";
diff --git a/third_party/nix/src/libexpr/primops/fetchMercurial.cc b/third_party/nix/src/libexpr/primops/fetchMercurial.cc
index 0367b2120b66..df42b6d94884 100644
--- a/third_party/nix/src/libexpr/primops/fetchMercurial.cc
+++ b/third_party/nix/src/libexpr/primops/fetchMercurial.cc
@@ -92,7 +92,8 @@ HgInfo exportMercurial(ref<Store> store, const std::string& uri,
   time_t now = time(0);
   struct stat st;
   if (stat(stampFile.c_str(), &st) != 0 ||
-      (uint64_t)st.st_mtime + settings.tarballTtl <= (uint64_t)now) {
+      static_cast<uint64_t>(st.st_mtime) + settings.tarballTtl <=
+          static_cast<uint64_t>(now)) {
     /* Except that if this is a commit hash that we already have,
        we don't have to pull again. */
     if (!(std::regex_match(rev, commitHashRegex) && pathExists(cacheDir) &&