diff --git a/src/cache_manager.h b/src/cache_manager.h
index 886e2bdf..311f6fcd 100644
--- a/src/cache_manager.h
+++ b/src/cache_manager.h
@@ -5,6 +5,7 @@
 #include <functional>
 #include <memory>
 #include <string>
+#include <vector>
 
 struct Config;
 struct IndexFile;
@@ -41,4 +42,4 @@ struct ICacheManager {
   virtual void IterateLoadedCaches(std::function<void(IndexFile*)> fn) = 0;
 };
 
-void WriteToCache(Config* config, IndexFile& file);
\ No newline at end of file
+void WriteToCache(Config* config, IndexFile& file);