diff --git a/src/Type.cc b/src/Type.cc
index fd1069170d..d461f3c1e5 100644
--- a/src/Type.cc
+++ b/src/Type.cc
@@ -1701,7 +1701,7 @@ void EnumType::AddNameInternal(const string& full_name, zeek_int_t val) {
     rev_names[val] = full_name;
 
     if ( ! vals.contains(val) ) {
-        if ( counter >= 0 && val == vals.size() )
+        if ( counter >= 0 && val == static_cast<zeek_int_t>(vals.size()) )
             ++counter;
         vals[val] = make_intrusive<EnumVal>(IntrusivePtr{NewRef{}, this}, val);
     }