Relate one-to-many on each-other?

Okay so my schema might be a little bit confusing, and maybe it's not correct to do it this way. But I have a case where items are displayed under, let's call it "Project". So projects can have categories, but in any given category there can be an "Item". Then you can click into said "Item" and it can have categories within it that then organize it and can then have "sub-items". Why am I getting this error saying Function implicitly has return type 'any', even though it seems like the query itself works fine. And creating items/categories works just fine. But due to this 'any' type, I'm not getting any type definitions on my queries. Thanks!