diff --git a/vyper/codegen/expr.py b/vyper/codegen/expr.py
index 3fe2de05f8..7d51669b33 100644
--- a/vyper/codegen/expr.py
+++ b/vyper/codegen/expr.py
@@ -693,7 +693,7 @@ def parse_Call(self):
             (arg0,) = self.expr.args
             arg_ir = Expr(arg0, self.context).ir_node
 
-            assert isinstance(arg_ir.typ, (AddressT, InterfaceT)), arg_ir.typ
+            assert isinstance(arg_ir.typ, AddressT), arg_ir.typ
             arg_ir.typ = self.expr._metadata["type"]
 
             return arg_ir