Auto merge of #120639 - fee1-dead-contrib:new-effects-desugaring, r=oli-obk

Implement new effects desugaring

cc `@rust-lang/project-const-traits.` Will write down notes once I have finished.

* [x] See if we want `T: Tr` to desugar into `T: Tr, T::Effects: Compat<true>`
* [x] Fix ICEs on `type Assoc: ~const Tr` and `type Assoc<T: ~const Tr>`
* [ ] add types and traits to minicore test
* [ ] update rustc-dev-guide

Fixes #119717
Fixes #123664
Fixes #124857
Fixes #126148

compiler/rustc_next_trait_solver/src/solve/assembly/mod.rs

@@ -269,6 +269,11 @@ where
         ecx: &mut EvalCtxt<'_, D>,
         goal: Goal<I, Self>,
     ) -> Vec<Candidate<I>>;
+
+    fn consider_builtin_effects_intersection_candidate(
+        ecx: &mut EvalCtxt<'_, D>,
+        goal: Goal<I, Self>,
+    ) -> Result<Candidate<I>, NoSolution>;
 }
 
 impl<D, I> EvalCtxt<'_, D>
@@ -420,6 +425,8 @@ where
             G::consider_builtin_destruct_candidate(self, goal)
         } else if cx.is_lang_item(trait_def_id, TraitSolverLangItem::TransmuteTrait) {
             G::consider_builtin_transmute_candidate(self, goal)
+        } else if cx.is_lang_item(trait_def_id, TraitSolverLangItem::EffectsIntersection) {
+            G::consider_builtin_effects_intersection_candidate(self, goal)
         } else {
             Err(NoSolution)
         };