diff --git a/src/library/tactic/simplify.cpp b/src/library/tactic/simplify.cpp
index 46aa8b8558..77b0bfde91 100644
--- a/src/library/tactic/simplify.cpp
+++ b/src/library/tactic/simplify.cpp
@@ -288,7 +288,7 @@ simp_result simplify_core_fn::try_user_congr(expr const & e, simp_lemma const &
             if (r_congr_hyp.has_proof())
                 simplified = true;
 
-            lean_assert(is_meta(h_rhs));
+            lean_assert(is_metavar_app(h_rhs));
             buffer<expr> new_val_meta_args;
             expr new_val_meta = get_app_args(h_rhs, new_val_meta_args);
             lean_assert(is_metavar(new_val_meta));