diff --git a/cpp/ql/src/filters/ImportAdditionalLibraries.ql b/cpp/ql/src/filters/ImportAdditionalLibraries.ql
index 1d54da5f6e7..261ee3de0ca 100644
--- a/cpp/ql/src/filters/ImportAdditionalLibraries.ql
+++ b/cpp/ql/src/filters/ImportAdditionalLibraries.ql
@@ -14,6 +14,7 @@ import semmle.code.cpp.dataflow.DataFlow2
 import semmle.code.cpp.dataflow.DataFlow3
 import semmle.code.cpp.dataflow.DataFlow4
 import semmle.code.cpp.dataflow.TaintTracking
+import semmle.code.cpp.valuenumbering.HashCons
 
 from File f, string tag
 where none()