diff --git a/vyper/codegen/ir_node.py b/vyper/codegen/ir_node.py
index 9d39ebd033..97d9c45fb6 100644
--- a/vyper/codegen/ir_node.py
+++ b/vyper/codegen/ir_node.py
@@ -405,7 +405,8 @@ def unique_symbols(self):
         for arg in children:
             s = arg.unique_symbols
             non_uniques = ret.intersection(s)
-            assert len(non_uniques) == 0, f"non-unique symbols {non_uniques}"
+            if len(non_uniques) != 0:  # pragma: nocover
+                raise CompilerPanic(f"non-unique symbols {non_uniques}")
             ret |= s
         return ret
 
diff --git a/vyper/venom/ir_node_to_venom.py b/vyper/venom/ir_node_to_venom.py
index 4fca95be90..85172c70e1 100644
--- a/vyper/venom/ir_node_to_venom.py
+++ b/vyper/venom/ir_node_to_venom.py
@@ -114,6 +114,8 @@
 
 # convert IRnode directly to venom
 def ir_node_to_venom(ir: IRnode) -> IRContext:
+    _ = ir.unique_symbols  # run unique symbols check
+
     global _global_symbols, _external_functions
     _global_symbols = {}
     _external_functions = {}