diff --git a/compiler/rustc_type_ir/src/search_graph/mod.rs b/compiler/rustc_type_ir/src/search_graph/mod.rs index 6c67bf13ac7..18a5a85dfa8 100644 --- a/compiler/rustc_type_ir/src/search_graph/mod.rs +++ b/compiler/rustc_type_ir/src/search_graph/mod.rs @@ -300,17 +300,7 @@ impl, X: Cx> SearchGraph { // We update both the head of this cycle to rerun its evaluation until // we reach a fixpoint and all other cycle participants to make sure that // their result does not get moved to the global cache. - fn tag_cycle_participants( - stack: &mut IndexVec>, - usage_kind: Option, - head: StackDepth, - ) { - if let Some(usage_kind) = usage_kind { - stack[head].has_been_used = - Some(stack[head].has_been_used.map_or(usage_kind, |prev| prev.merge(usage_kind))); - } - debug_assert!(stack[head].has_been_used.is_some()); - + fn tag_cycle_participants(stack: &mut IndexVec>, head: StackDepth) { // The current root of these cycles. Note that this may not be the final // root in case a later goal depends on a goal higher up the stack. let mut current_root = head; @@ -403,7 +393,8 @@ impl, X: Cx> SearchGraph { // We have a nested goal which is already in the provisional cache, use // its result. We do not provide any usage kind as that should have been // already set correctly while computing the cache entry. - Self::tag_cycle_participants(&mut self.stack, None, entry.head); + debug_assert!(self.stack[entry.head].has_been_used.is_some()); + Self::tag_cycle_participants(&mut self.stack, entry.head); return entry.result; } else if let Some(stack_depth) = cache_entry.stack_depth { debug!("encountered cycle with depth {stack_depth:?}"); @@ -416,11 +407,13 @@ impl, X: Cx> SearchGraph { let is_coinductive_cycle = Self::stack_coinductive_from(cx, &self.stack, stack_depth); let cycle_kind = if is_coinductive_cycle { CycleKind::Coinductive } else { CycleKind::Inductive }; - Self::tag_cycle_participants( - &mut self.stack, - Some(UsageKind::Single(cycle_kind)), - stack_depth, + let usage_kind = UsageKind::Single(cycle_kind); + self.stack[stack_depth].has_been_used = Some( + self.stack[stack_depth] + .has_been_used + .map_or(usage_kind, |prev| prev.merge(usage_kind)), ); + Self::tag_cycle_participants(&mut self.stack, stack_depth); // Return the provisional result or, if we're in the first iteration, // start with no constraints.