ISE: Self reference in computed using __source__

[CarsonF]

• EdgeDB Version: 3.0-rc.2+eb06d9e
• EdgeDB CLI Version: 3.1.3+2f81fc4
• OS Version: OSX 13.2.1

Steps to Reproduce:

1. start edgedb watch
2. add

   abstract type Pinnable {
     property pinned := __source__ in <Pinnable>{};
   }
   

3. add

   type Foo extending Pinnable {}
   

Schema migration error: InternalServerError: object type 'default::Foo' has no link or property '__type__'

[elprans]

Also affects constraints:

module person{
    abstract type Person {
        multi link friends : Person{
            constraint expression on (
                    __subject__ != __subject__@source
                );
        };

    }

    type Employee extending Person{
        department : str;
    }
}