Remove out-of-date comments.
These refer to code that no longer exists.
diff --git a/src/librustc_data_structures/obligation_forest/mod.rs b/src/librustc_data_structures/obligation_forest/mod.rs
index 595323d..731d82b 100644
--- a/src/librustc_data_structures/obligation_forest/mod.rs
+++ b/src/librustc_data_structures/obligation_forest/mod.rs
@@ -61,14 +61,6 @@
//! results. This is used by the `FulfillmentContext` to decide when it
//! has reached a steady state.
//!
-//! #### Snapshots
-//!
-//! The `ObligationForest` supports a limited form of snapshots; see
-//! `start_snapshot`, `commit_snapshot`, and `rollback_snapshot`. In
-//! particular, you can use a snapshot to roll back new root
-//! obligations. However, it is an error to attempt to
-//! `process_obligations` during a snapshot.
-//!
//! ### Implementation details
//!
//! For the most part, comments specific to the implementation are in the
@@ -151,10 +143,6 @@
/// At the end of processing, those nodes will be removed by a
/// call to `compress`.
///
- /// At all times we maintain the invariant that every node appears
- /// at a higher index than its parent. This is needed by the
- /// backtrace iterator (which uses `split_at`).
- ///
/// Ideally, this would be an `IndexVec<NodeIndex, Node<O>>`. But that is
/// slower, because this vector is accessed so often that the
/// `u32`-to-`usize` conversions required for accesses are significant.
@@ -288,8 +276,6 @@
}
/// Registers an obligation.
- ///
- /// This CAN be done in a snapshot
pub fn register_obligation(&mut self, obligation: O) {
// Ignore errors here - there is no guarantee of success.
let _ = self.register_obligation_at(obligation, None);
@@ -355,8 +341,6 @@
}
/// Converts all remaining obligations to the given error.
- ///
- /// This cannot be done during a snapshot.
pub fn to_errors<E: Clone>(&mut self, error: E) -> Vec<Error<O, E>> {
let mut errors = vec![];
for i in 0..self.nodes.len() {
