diff options
Diffstat (limited to 'src/librustc_data_structures')
| -rw-r--r-- | src/librustc_data_structures/obligation_forest/mod.rs | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/src/librustc_data_structures/obligation_forest/mod.rs b/src/librustc_data_structures/obligation_forest/mod.rs index 990dc66c66a..c66011d4118 100644 --- a/src/librustc_data_structures/obligation_forest/mod.rs +++ b/src/librustc_data_structures/obligation_forest/mod.rs @@ -193,15 +193,18 @@ impl<O: ForestObligation> ObligationForest<O> { Entry::Occupied(o) => { debug!("register_obligation_at({:?}, {:?}) - duplicate of {:?}!", obligation, parent, o.get()); + let node = &mut self.nodes[o.get().get()]; if let Some(parent) = parent { - if self.nodes[o.get().get()].dependents.contains(&parent) { - debug!("register_obligation_at({:?}, {:?}) - duplicate subobligation", - obligation, parent); - } else { - self.nodes[o.get().get()].dependents.push(parent); + // If the node is already in `waiting_cache`, it's already + // been marked with a parent. (It's possible that parent + // has been cleared by `apply_rewrites`, though.) So just + // dump `parent` into `node.dependents`... unless it's + // already in `node.dependents` or `node.parent`. + if !node.dependents.contains(&parent) && Some(parent) != node.parent { + node.dependents.push(parent); } } - if let NodeState::Error = self.nodes[o.get().get()].state.get() { + if let NodeState::Error = node.state.get() { Err(()) } else { Ok(()) |