diff options
| -rw-r--r-- | src/librustc_mir/borrow_check/nll/constraint_set.rs | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/src/librustc_mir/borrow_check/nll/constraint_set.rs b/src/librustc_mir/borrow_check/nll/constraint_set.rs index cbef674b269..78bd4504443 100644 --- a/src/librustc_mir/borrow_check/nll/constraint_set.rs +++ b/src/librustc_mir/borrow_check/nll/constraint_set.rs @@ -38,6 +38,10 @@ impl ConstraintSet { } } + /// Once all constraints have been added, `link()` is used to thread together the constraints + /// based on which would be affected when a particular region changes. See the next field of + /// `OutlivesContraint` for more details. + /// link returns a map that is needed later by `each_affected_by_dirty`. pub fn link(&mut self, len: usize) -> IndexVec<RegionVid, Option<ConstraintIndex>> { let mut map = IndexVec::from_elem_n(None, len); @@ -51,6 +55,11 @@ impl ConstraintSet { map } + /// When a region R1 changes, we need to reprocess all constraints R2: R1 to take into account + /// any new elements that R1 now has. This method will quickly enumerate all such constraints + /// (that is, constraints where R1 is in the "subregion" position). + /// To use it, invoke with `map[R1]` where map is the map returned by `link`; + /// the callback op will be invoked for each affected constraint. pub fn each_affected_by_dirty( &self, mut opt_dep_idx: Option<ConstraintIndex>, |