--- a/startupcache/StartupCache.cpp
+++ b/startupcache/StartupCache.cpp
@@ -435,18 +435,18 @@ StartupCache::WriteToDisk()
     return;
   }
 
   CacheWriteHolder holder;
   holder.stream = stream;
   holder.writer = zipW;
   holder.time = now;
 
-  for (auto key = mPendingWrites.begin(); key != mPendingWrites.end(); key++) {
-    CacheCloseHelper(*key, mTable.Get(*key), &holder);
+  for (auto& key : mPendingWrites) {
+    CacheCloseHelper(key, mTable.Get(key), &holder);
   }
   mPendingWrites.Clear();
   mTable.Clear();
 
   // Close the archive so Windows doesn't choke.
   mArchive = nullptr;
   zipW->Close();