This issue was originally filed by Ilya.Va...@gmail.com

ArgumentError is not thrown on co19 tests:

LibTest/core/Symbol/Symbol_A01_t03
LibTest/core/Symbol/Symbol_A01_t04
LibTest/core/Symbol/Symbol_A01_t05

"An ArgumentError is thrown if name starts with an underscore, or if name is not a String. An ArgumentError is thrown if name is not an empty string and is not a valid qualified identifier optionally followed by '='"

    new Symbol('_foo');
    new Symbol(null);
    new Symbol(new Symbol(''));
    new Symbol('+++');
    new Symbol('2013year');