test unknown type exception does not have empty hint

tests/functional/syntax/exceptions/test_unknown_type.py

@@ -0,0 +1,14 @@
+import pytest
+
+from vyper import compiler
+from vyper.exceptions import UnknownType
+
+def test_unknown_type_exception():
+    code = """
+@internal
+def foobar(token: IERC20):
+    pass
+    """
+    with pytest.raises(UnknownType) as e:
+        compiler.compile_code(code)
+    assert "(hint: )" not in str(e.value)