cycle_participants to nested_goals

Author: lcnr

compiler/rustc_next_trait_solver/src/solve/search_graph.rs

@@ -71,7 +71,7 @@ struct StackEntry<I: Interner> {
     /// C :- D
     /// D :- C
     /// ```
-    cycle_participants: HashSet<CanonicalInput<I>>,
+    nested_goals: HashSet<CanonicalInput<I>>,
     /// Starts out as `None` and gets set when rerunning this
     /// goal in case we encounter a cycle.
     provisional_result: Option<QueryResult<I>>,
@@ -215,8 +215,8 @@ impl<I: Interner> SearchGraph<I> {
         let current_cycle_root = &mut stack[current_root.as_usize()];
         for entry in cycle_participants {
             entry.non_root_cycle_participant = entry.non_root_cycle_participant.max(Some(head));
-            current_cycle_root.cycle_participants.insert(entry.input);
-            current_cycle_root.cycle_participants.extend(mem::take(&mut entry.cycle_participants));
+            current_cycle_root.nested_goals.insert(entry.input);
+            current_cycle_root.nested_goals.extend(mem::take(&mut entry.nested_goals));
         }
     }
 
@@ -335,7 +335,7 @@ impl<I: Interner> SearchGraph<I> {
                 non_root_cycle_participant: None,
                 encountered_overflow: false,
                 has_been_used: HasBeenUsed::empty(),
-                cycle_participants: Default::default(),
+                nested_goals: Default::default(),
                 provisional_result: None,
             };
             assert_eq!(self.stack.push(entry), depth);
@@ -389,15 +389,15 @@ impl<I: Interner> SearchGraph<I> {
             //
             // We must not use the global cache entry of a root goal if a cycle
             // participant is on the stack. This is necessary to prevent unstable
-            // results. See the comment of `StackEntry::cycle_participants` for
+            // results. See the comment of `StackEntry::nested_goals` for
             // more details.
             self.global_cache(cx).insert(
                 cx,
                 input,
                 proof_tree,
                 reached_depth,
                 final_entry.encountered_overflow,
-                final_entry.cycle_participants,
+                final_entry.nested_goals,
                 dep_node,
                 result,
             )
@@ -544,27 +544,27 @@ impl<I: Interner> SearchGraph<I> {
                 non_root_cycle_participant,
                 encountered_overflow: _,
                 has_been_used,
-                ref cycle_participants,
+                ref nested_goals,
                 provisional_result,
             } = *entry;
             let cache_entry = provisional_cache.get(&entry.input).unwrap();
             assert_eq!(cache_entry.stack_depth, Some(depth));
             if let Some(head) = non_root_cycle_participant {
                 assert!(head < depth);
-                assert!(cycle_participants.is_empty());
+                assert!(nested_goals.is_empty());
                 assert_ne!(stack[head].has_been_used, HasBeenUsed::empty());
 
                 let mut current_root = head;
                 while let Some(parent) = stack[current_root].non_root_cycle_participant {
                     current_root = parent;
                 }
-                assert!(stack[current_root].cycle_participants.contains(&input));
+                assert!(stack[current_root].nested_goals.contains(&input));
             }
 
-            if !cycle_participants.is_empty() {
+            if !nested_goals.is_empty() {
                 assert!(provisional_result.is_some() || !has_been_used.is_empty());
                 for entry in stack.iter().take(depth.as_usize()) {
-                    assert_eq!(cycle_participants.get(&entry.input), None);
+                    assert_eq!(nested_goals.get(&entry.input), None);
                 }
             }
         }