6 files changed, 11 insertions, 21 deletions

diff --git a/src/libstore/build.cc b/src/libstore/build.cc
index 9a6729f9e..0e0f8a545 100644
--- a/src/libstore/build.cc
+++ b/src/libstore/build.cc
@@ -568,10 +568,9 @@ UserLock::UserLock()
 
         {
             auto lockedPaths(lockedPaths_.lock());
-            if (lockedPaths->count(fnUserLock))
+            if (!lockedPaths->insert(fnUserLock).second)
                 /* We already have a lock on this one. */
                 continue;
-            lockedPaths->insert(fnUserLock);
         }
 
         try {
@@ -620,8 +619,8 @@ UserLock::UserLock()
 UserLock::~UserLock()
 {
     auto lockedPaths(lockedPaths_.lock());
-    assert(lockedPaths->count(fnUserLock));
-    lockedPaths->erase(fnUserLock);
+    auto erased = lockedPaths->erase(fnUserLock);
+    assert(erased);
 }
 
 
@@ -1125,10 +1124,8 @@ void DerivationGoal::addWantedOutputs(const StringSet & outputs)
         needRestart = true;
     } else
         for (auto & i : outputs)
-            if (wantedOutputs.find(i) == wantedOutputs.end()) {
-                wantedOutputs.insert(i);
+            if (wantedOutputs.insert(i).second)
                 needRestart = true;
-            }
 }
 
 
diff --git a/src/libstore/builtins/buildenv.cc b/src/libstore/builtins/buildenv.cc
index 74e706664..096593886 100644
--- a/src/libstore/builtins/buildenv.cc
+++ b/src/libstore/builtins/buildenv.cc
@@ -123,8 +123,7 @@ static Path out;
 
 static void addPkg(const Path & pkgDir, int priority)
 {
-    if (done.count(pkgDir)) return;
-    done.insert(pkgDir);
+    if (!done.insert(pkgDir).second) return;
     createLinks(pkgDir, out, priority);
 
     try {
diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index a2af51d0e..859094e61 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -1292,8 +1292,7 @@ void LocalStore::verifyPath(const Path & path, const PathSet & store,
 {
     checkInterrupt();
 
-    if (done.find(path) != done.end()) return;
-    done.insert(path);
+    if (!done.insert(path).second) return;
 
     if (!isStorePath(path)) {
         printError(format("path '%1%' is not in the Nix store") % path);
diff --git a/src/libstore/misc.cc b/src/libstore/misc.cc
index dddf13430..05b93d4c9 100644
--- a/src/libstore/misc.cc
+++ b/src/libstore/misc.cc
@@ -29,8 +29,7 @@ void Store::computeFSClosure(const PathSet & startPaths,
         {
             auto state(state_.lock());
             if (state->exc) return;
-            if (state->paths.count(path)) return;
-            state->paths.insert(path);
+            if (!state->paths.insert(path).second) return;
             state->pending++;
         }
 
@@ -175,8 +174,7 @@ void Store::queryMissing(const PathSet & targets,
 
         {
             auto state(state_.lock());
-            if (state->done.count(path)) return;
-            state->done.insert(path);
+            if (!state->done.insert(path).second) return;
         }
 
         DrvPathWithOutputs i2 = parseDrvPathWithOutputs(path);
@@ -252,8 +250,7 @@ Paths Store::topoSortPaths(const PathSet & paths)
         if (parents.find(path) != parents.end())
             throw BuildError(format("cycle detected in the references of '%1%' from '%2%'") % path % *parent);
 
-        if (visited.find(path) != visited.end()) return;
-        visited.insert(path);
+        if (!visited.insert(path).second) return;
         parents.insert(path);
 
         PathSet references;
diff --git a/src/libstore/references.cc b/src/libstore/references.cc
index 5b7eb1f84..0dcc264c3 100644
--- a/src/libstore/references.cc
+++ b/src/libstore/references.cc
@@ -36,11 +36,10 @@ static void search(const unsigned char * s, size_t len,
             }
         if (!match) continue;
         string ref((const char *) s + i, refLength);
-        if (hashes.find(ref) != hashes.end()) {
+        if (hashes.erase(ref)) {
             debug(format("found reference to '%1%' at offset '%2%'")
                   % ref % i);
             seen.insert(ref);
-            hashes.erase(ref);
         }
         ++i;
     }
diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index 5f63c53b5..be13fa49a 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -954,8 +954,7 @@ std::list<ref<Store>> getDefaultSubstituters()
         StringSet done;
 
         auto addStore = [&](const std::string & uri) {
-            if (done.count(uri)) return;
-            done.insert(uri);
+            if (!done.insert(uri).second) return;
             try {
                 stores.push_back(openStore(uri));
             } catch (Error & e) {