Show how I want to track homogenous resources in a provider but still return a specific type so users can still interact with it - even if read-only.

downcating.rs

pub struct AwsProvider(Inner);

struct Inner {                                                                                                 
  creds: Credentials,                                                                                    
  region: String,                                                                                        
  tracked_resources: RwLock<Vec<Box<dyn Resource<Aws>>>>,
}  

// TODO: it would be nice if this could magically put the
// reosurce on the heap (Arc<Box<...>>) and then return
// something like Arc<Box<T>>, assuming `track<T>`
pub fn track(&mut self, resource: Box<dyn Resource<Aws>>) {
   self.0.tracked_resources.write().unwrap().push(resource);
}

// -----------------------------------------------------------
// different file...
// -----------------------------------------------------------

// This is the end of a "builder" that will stash away the resource for later usage:
pub fn build(mut self) -> Option<Arc<Box<Bucket>>> {
      let bucket = Bucket { Bucket
        name: self.name,
        acl: self.acl,
        website: self.website,
        tags: self.tags,
       };

     // TODO: this is annoying!
     // receive a Arc<Box<Bucket>> in return.
     // `track(...)` needs to work with `dyn Resource<C: Cloud>` though.
     let to_be_stashed_away: Box<dyn Resource<Aws>> = Box::new(bucket.clone());

     self.provider.track(to_be_stashed_away);

     Some(Arc::new(Box::new(bucket)))
   }
}

I have left out the aysnc part from async_trait thinking it might have something to do with it but no 😢

// #[async_trait]
pub trait Resource<C: Cloud>: 'static + std::fmt::Debug + Send + Sync {
   /* async */ fn create(&self, provider: &<C as Cloud>::Provider) -> Result<RealState, String>; // Come up with a better error story
      fn as_dyn_any(&self) -> &(dyn Any + '_) {
        &self
      }
}

And the error is:

error[E0477]: the type `&Self` does not fulfill the required lifetime
  --> luminary/src/lib.rs:34:9
   |
34 |         &self
   |         ^^^^^
   |
   = note: type must satisfy the static lifetime

error[E0759]: `self` has an anonymous lifetime `'_` but it needs to satisfy a `'static` lifetime requirement
  --> luminary/src/lib.rs:34:9
   |
33 |     fn as_dyn_any(&self) -> &(dyn Any + '_) {
   |                   ----- this data with an anonymous lifetime `'_`...
34 |         &self
   |         ^^^^^ ...is captured and required to live as long as `'static` here