diff --git a/tests/functional/codegen/test_interfaces.py b/tests/functional/codegen/test_interfaces.py
index b6cb8c0d68..6a9c019d02 100644
--- a/tests/functional/codegen/test_interfaces.py
+++ b/tests/functional/codegen/test_interfaces.py
@@ -958,3 +958,11 @@ def bar(a:int32) -> uint256:
         "external_interface"
     ]
     compile_code(out, contract_path="test.vyi", output_formats=["external_interface"])
+
+
+@pytest.mark.xfail
+def test_weird_interface_name():
+    out = compile_code("", contract_path="_.vyi", output_formats=["external_interface"])[
+        "external_interface"
+    ]
+    assert "interface _:" in out