Rollup merge of #109580 - compiler-errors:new-solver-fixmes, r=lcnr

Remove some stale FIXMEs in new solver

Some FIXMEs are no longer needed

compiler/rustc_trait_selection/src/solve/mod.rs

@@ -9,8 +9,6 @@
 //! FIXME(@lcnr): Write that section. If you read this before then ask me
 //! about it on zulip.
 
-// FIXME: uses of `infcx.at` need to enable deferred projection equality once that's implemented.
-
 use rustc_hir::def_id::DefId;
 use rustc_infer::infer::canonical::{Canonical, CanonicalVarValues};
 use rustc_infer::traits::query::NoSolution;
@@ -105,8 +103,6 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
         goal: Goal<'tcx, SubtypePredicate<'tcx>>,
     ) -> QueryResult<'tcx> {
         if goal.predicate.a.is_ty_var() && goal.predicate.b.is_ty_var() {
-            // FIXME: Do we want to register a subtype relation between these vars?
-            // That won't actually reflect in the query response, so it seems moot.
             self.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS)
         } else {
             self.sub(goal.param_env, goal.predicate.a, goal.predicate.b)?;

compiler/rustc_trait_selection/src/solve/search_graph/mod.rs

@@ -78,8 +78,6 @@ impl<'tcx> SearchGraph<'tcx> {
         tcx: TyCtxt<'tcx>,
         goal: CanonicalGoal<'tcx>,
     ) -> Result<(), QueryResult<'tcx>> {
-        // FIXME: start by checking the global cache
-
         // Look at the provisional cache to check for cycles.
         let cache = &mut self.provisional_cache;
         match cache.lookup_table.entry(goal) {