diff --git a/rumur/src/smt/simplify.cc b/rumur/src/smt/simplify.cc
index 61f94390..1e9d1231 100644
--- a/rumur/src/smt/simplify.cc
+++ b/rumur/src/smt/simplify.cc
@@ -235,7 +235,7 @@ class Simplifier : public BaseTraversal {
       if (auto f = dynamic_cast<Function *>(c.get()))
         declare_func(*f);
     }
-    solver->open_scope();
+    solver->close_scope();
   }
 
   void visit_mul(Mul &n) final { visit_bexpr(n); }