Add support for assoc items

- fix typo - `let _unused = … would be enough` instead of `let _unused: = …`
- Merge tests checking for unimplemented traits.

Author: Yarwin

itest/rust/src/object_tests/dyn_gd_test.rs

@@ -11,7 +11,7 @@ use godot::prelude::*;
 #[itest]
 fn dyn_gd_creation_bind() {
     // type can't be inferred because RefcHealth implements more than one AsDyn<...> trait.
-    // otherwise let _unused: = … would be enough
+    // otherwise let _unused = … would be enough
     let _unused: DynGd<RefcHealth, dyn Health> = Gd::from_object(RefcHealth { hp: 1 }).into_dyn();
     let _unused: DynGd<RefcHealth, dyn HealthWithAssociatedType<HealthType = u8>> =
         Gd::from_object(RefcHealth { hp: 1 }).into_dyn();
@@ -436,11 +436,6 @@ fn dyn_gd_error_unimplemented_trait() {
         err.to_string(),
         format!("none of the classes derived from `RefCounted` have been linked to trait `dyn Health` with #[godot_dyn]: {obj:?}")
     );
-}
-
-#[itest]
-fn dyn_gd_error_unimplemented_trait_with_associated_type() {
-    let obj = RefCounted::new_gd();
 
     let variant = obj.to_variant();
     let back = variant.try_to::<DynGd<RefCounted, dyn HealthWithAssociatedType<HealthType = u8>>>();