Finally. I was missguided about hundred times. Wrong fixes, fixes that broken something elsewhere later, etc. etc. Also, another (major) codechange will arrive in another PR... Please take a look, sometimes it's a magic for me.

Yeah, I like this much better 👍 Although the if ($type instanceof TemplateType) as first thing in isSuperTypeOf implementation feels dirty. Why instanceof CompoundType with isSubTypeOf call later doesn't work?

Why instanceof CompoundType with isSubTypeOf call later doesn't work?

Because I didn't know what is it exactly :D Ok, I've tried to rework it. Actually, many interfaces and theirs methods would benefit of documenting their meaning.

I'd like the number of if ($something instanceof SomeType) to go down, especially in Type::isSuperTypeOf implementations. Because with them, adding a new type becomes exponentially more work...

I'm really grateful for your contribution :) I'd say that after 22 hours, you're an expert now in this area :D

Look at CompoundType implementations - it's a hack used to when accepts or isSuperTypeOf needs special handling for some types... Since TemplateType is one of them, it should work without an extra if...

Oh, you’ve already changed the code. Doesn’t something in TemplateObjectWithoutClassType also need to change? (I’m on mobile.)

Doesn’t something in TemplateObjectWithoutClassType also need to change? (I’m on mobile.)

Need investigation, obviously we are missing more tests, changing it doesn't fix/break anything.

Works great, thank you! Not sure what's going on in TemplateObjectWithoutClassType and why it doesn't need the changes...