Rollup merge of #94215 - lcnr:leak-check, r=jackh726

trait system: comments and small nonfunctional changes

r? `@nikomatsakis` because of the leak-check check removal

compiler/rustc_trait_selection/src/traits/coherence.rs

@@ -160,20 +160,12 @@ fn overlap<'cx, 'tcx>(
     );
 
     selcx.infcx().probe_maybe_skip_leak_check(skip_leak_check.is_yes(), |snapshot| {
-        overlap_within_probe(
-            selcx,
-            skip_leak_check,
-            impl1_def_id,
-            impl2_def_id,
-            overlap_mode,
-            snapshot,
-        )
+        overlap_within_probe(selcx, impl1_def_id, impl2_def_id, overlap_mode, snapshot)
     })
 }
 
 fn overlap_within_probe<'cx, 'tcx>(
     selcx: &mut SelectionContext<'cx, 'tcx>,
-    skip_leak_check: SkipLeakCheck,
     impl1_def_id: DefId,
     impl2_def_id: DefId,
     overlap_mode: OverlapMode,
@@ -207,11 +199,11 @@ fn overlap_within_probe<'cx, 'tcx>(
         }
     }
 
-    if !skip_leak_check.is_yes() {
-        if infcx.leak_check(true, snapshot).is_err() {
-            debug!("overlap: leak check failed");
-            return None;
-        }
+    // We disable the leak when when creating the `snapshot` by using
+    // `infcx.probe_maybe_disable_leak_check`.
+    if infcx.leak_check(true, snapshot).is_err() {
+        debug!("overlap: leak check failed");
+        return None;
     }
 
     let intercrate_ambiguity_causes = selcx.take_intercrate_ambiguity_causes();

compiler/rustc_trait_selection/src/traits/fulfill.rs

@@ -314,7 +314,7 @@ impl<'a, 'b, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'b, 'tcx> {
             return ProcessResult::Unchanged;
         }
 
-        self.progress_changed_obligations(pending_obligation)
+        self.process_changed_obligations(pending_obligation)
     }
 
     fn process_backedge<'c, I>(
@@ -338,7 +338,7 @@ impl<'a, 'b, 'tcx> FulfillProcessor<'a, 'b, 'tcx> {
     // actually uses this, so move this part of the code
     // out of that loop.
     #[inline(never)]
-    fn progress_changed_obligations(
+    fn process_changed_obligations(
         &mut self,
         pending_obligation: &mut PendingPredicateObligation<'tcx>,
     ) -> ProcessResult<PendingPredicateObligation<'tcx>, FulfillmentErrorCode<'tcx>> {

compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs

@@ -389,7 +389,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         for bound in matching_bounds {
             // FIXME(oli-obk): it is suspicious that we are dropping the constness and
             // polarity here.
-            let wc = self.evaluate_where_clause(stack, bound.map_bound(|t| t.trait_ref))?;
+            let wc = self.where_clause_may_apply(stack, bound.map_bound(|t| t.trait_ref))?;
             if wc.may_apply() {
                 candidates.vec.push(ParamCandidate(bound));
             }

compiler/rustc_trait_selection/src/traits/select/mod.rs

@@ -1481,7 +1481,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             .map_err(|_| ())
     }
 
-    fn evaluate_where_clause<'o>(
+    fn where_clause_may_apply<'o>(
         &mut self,
         stack: &TraitObligationStack<'o, 'tcx>,
         where_clause_trait_ref: ty::PolyTraitRef<'tcx>,