improvements to adjust_rank

compiler/solve/src/solve.rs

@@ -1539,21 +1539,24 @@ fn adjust_rank(
     group_rank: Rank,
     var: Variable,
 ) -> Rank {
-    let (desc_rank, desc_mark) = subs.get_rank_mark(var);
+    let desc = subs.get_ref_mut(var);
+
+    let desc_rank = desc.rank;
+    let desc_mark = desc.mark;
 
     if desc_mark == young_mark {
-        // Mark the variable as visited before adjusting content, as it may be cyclic.
-        subs.set_mark(var, visit_mark);
-
         // SAFETY: in this function (and functions it calls, we ONLY modify rank and mark, never content!
         // hence, we can have an immutable reference to it even though we also have a mutable
         // reference to the Subs as a whole. This prevents a clone of the content, which turns out
         // to be quite expensive.
         let content = {
-            let ptr = &subs.get_ref(var).content as *const _;
+            let ptr = &desc.content as *const _;
             unsafe { &*ptr }
         };
 
+        // Mark the variable as visited before adjusting content, as it may be cyclic.
+        desc.mark = visit_mark;
+
         let max_rank = adjust_rank_content(subs, young_mark, visit_mark, group_rank, content);
 
         subs.set_rank_mark(var, max_rank, visit_mark);
@@ -1566,7 +1569,8 @@ fn adjust_rank(
         let min_rank = group_rank.min(desc_rank);
 
         // TODO from elm-compiler: how can min_rank ever be group_rank?
-        subs.set_rank_mark(var, min_rank, visit_mark);
+        desc.rank = min_rank;
+        desc.mark = visit_mark;
 
         min_rank
     }

vendor/ena/src/unify/mod.rs

@@ -470,7 +470,7 @@ where
         K1: Into<K>,
     {
         let id = id.into();
-        let id = self.get_root_key_without_compacting(id);
+        let id = self.get_root_key(id);
         self.value_mut(id)
     }