Rollup merge of #80732 - spastorino:trait-inheritance-self2, r=nikomatsakis

Allow Trait inheritance with cycles on associated types take 2

This reverts the revert of #79209 and fixes the ICEs that's occasioned by that PR exposing some problems that are addressed in #80648 and #79811.
For easier review I'd say, check only the last commit, the first one is just a revert of the revert of #79209 which was already approved.

This also could be considered part or the actual fix of #79560 but I guess for that to be closed and fixed completely we would need to land #80648 and #79811 too.

r? `@nikomatsakis`
cc `@Aaron1011`

compiler/rustc_trait_selection/src/traits/mod.rs

@@ -65,7 +65,8 @@ pub use self::util::{
     get_vtable_index_of_object_method, impl_item_is_final, predicate_for_trait_def, upcast_choices,
 };
 pub use self::util::{
-    supertrait_def_ids, supertraits, transitive_bounds, SupertraitDefIds, Supertraits,
+    supertrait_def_ids, supertraits, transitive_bounds, transitive_bounds_that_define_assoc_type,
+    SupertraitDefIds, Supertraits,
 };
 
 pub use self::chalk_fulfill::FulfillmentContext as ChalkFulfillmentContext;