diff --git a/src/library/unifier.cpp b/src/library/unifier.cpp
index 6ad4548f5b..cf9be2b0c6 100644
--- a/src/library/unifier.cpp
+++ b/src/library/unifier.cpp
@@ -1440,7 +1440,7 @@ struct unifier_fn {
                 num++;
                 t = binding_body(t);
             }
-            if (num == margs.size())
+            if (num >= margs.size())
                 return mtype;
             return ensure_sufficient_args_core(mtype, 0, cs);
         }