diff options
| -rw-r--r-- | src/librustc/infer/region_inference/mod.rs | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/src/librustc/infer/region_inference/mod.rs b/src/librustc/infer/region_inference/mod.rs index 8351be49076..0bc388a0089 100644 --- a/src/librustc/infer/region_inference/mod.rs +++ b/src/librustc/infer/region_inference/mod.rs @@ -633,11 +633,12 @@ impl<'a, 'gcx, 'tcx> RegionVarBindings<'a, 'gcx, 'tcx> { debug!("RegionVarBindings: add_constraint({:?})", constraint); - if self.constraints.borrow_mut().insert(constraint, origin).is_none() { + self.constraints.borrow_mut().entry(constraint).or_insert_with(|| { if self.in_snapshot() { self.undo_log.borrow_mut().push(AddConstraint(constraint)); } - } + origin + }); } fn add_verify(&self, verify: Verify<'tcx>) { |