vscode datalog: spurious 'unbound variable in head' errors when nested

[vilterp]

These errors shouldn't be there:

Not sure why this isn't finding them: https://github.com/vilterp/datalog-ts/blob/4a79913676dd5f672010b7e788ed55946226eb3e/languageWorkbench/languages/dl/dl.ts#L68-L71

[vilterp]

Wait a sec, it's not even finding this?

wtf