diff --git a/cpp/ycm/LetterNodeListMap.cpp b/cpp/ycm/LetterNodeListMap.cpp
index 13c207ec..0f129d77 100644
--- a/cpp/ycm/LetterNodeListMap.cpp
+++ b/cpp/ycm/LetterNodeListMap.cpp
@@ -40,7 +40,9 @@ int IndexForChar( char letter ) {
 
 
 LetterNodeListMap::LetterNodeListMap() {
-  std::fill( letters_.begin(), letters_.end(), NULL );
+  std::fill( letters_.begin(),
+             letters_.end(),
+             static_cast< std::list< LetterNode * >* >( NULL ) );
 }