Auto merge of #93089 - pierwill:rm-outlivesconstraint-ord, r=michaelw…

…oerister

Remove ordering traits from `OutlivesConstraint`

In two cases where this ordering was used, I've replaced the sorting to use a key that does not rely on `DefId` being `Ord`. This is part of #90317. If I understand correctly, whether this is correct depends on whether the `RegionVid`s are tracked during incremental compilation. But I might be mistaken in this approach. cc `@cjgillot`

compiler/rustc_borrowck/src/constraints/mod.rs

@@ -72,7 +72,7 @@ impl<'tcx> Index<OutlivesConstraintIndex> for OutlivesConstraintSet<'tcx> {
     }
 }
 
-#[derive(Clone, PartialEq, Eq, PartialOrd, Ord)]
+#[derive(Clone, PartialEq, Eq)]
 pub struct OutlivesConstraint<'tcx> {
     // NB. The ordering here is not significant for correctness, but
     // it is for convenience. Before we dump the constraints in the

compiler/rustc_borrowck/src/region_infer/dump_mir.rs

@@ -72,7 +72,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         }
 
         let mut constraints: Vec<_> = self.constraints.outlives().iter().collect();
-        constraints.sort();
+        constraints.sort_by_key(|c| (c.sup, c.sub));
         for constraint in &constraints {
             let OutlivesConstraint { sup, sub, locations, category, variance_info: _ } = constraint;
             let (name, arg) = match locations {

compiler/rustc_borrowck/src/region_infer/mod.rs

@@ -612,7 +612,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     fn propagate_constraints(&mut self, _body: &Body<'tcx>) {
         debug!("constraints={:#?}", {
             let mut constraints: Vec<_> = self.constraints.outlives().iter().collect();
-            constraints.sort();
+            constraints.sort_by_key(|c| (c.sup, c.sub));
             constraints
                 .into_iter()
                 .map(|c| (c, self.constraint_sccs.scc(c.sup), self.constraint_sccs.scc(c.sub)))