Steps to reproduce:
CREATE OR REPLACE TYPE test_type AS OBJECT (
id NUMBER,
CONSTRUCTOR FUNCTION test_type RETURN SELF AS RESULT
);
CREATE OR REPLACE TYPE BODY test_type AS
CONSTRUCTOR FUNCTION test_type RETURN SELF AS RESULT AS BEGIN RETURN; END;
END;
CREATE TABLE toad_test ( val ANYDATA );
INSERT INTO toad_test VALUES ( anydata.convertObject( NEW test_type() ) );
Then open the table in a describe window and switch to Data.
SELECT * FROM toad_test
produces similar error messages but does not seem to crash TOAD: