diff --git a/cpp/ql/lib/semmle/code/cpp/ir/implementation/aliased_ssa/gvn/internal/ValueNumberingInternal.qll b/cpp/ql/lib/semmle/code/cpp/ir/implementation/aliased_ssa/gvn/internal/ValueNumberingInternal.qll
index d8862dcaa07..fce87447110 100644
--- a/cpp/ql/lib/semmle/code/cpp/ir/implementation/aliased_ssa/gvn/internal/ValueNumberingInternal.qll
+++ b/cpp/ql/lib/semmle/code/cpp/ir/implementation/aliased_ssa/gvn/internal/ValueNumberingInternal.qll
@@ -83,6 +83,7 @@ private predicate callValueNumber(
 private predicate callPartialValueNumber(
   NumberableCallInstruction call, int index, TCallPartialValueNumber head
 ) {
+  exists(call) and
   index = 1 and head = TNilArgument()
   or
   exists(TCallPartialValueNumber prev, TValueNumber prevVN |