diff --git a/compiler/rustc_borrowck/src/dataflow.rs b/compiler/rustc_borrowck/src/dataflow.rs
index 031dbe299d1..a615b383fee 100644
--- a/compiler/rustc_borrowck/src/dataflow.rs
+++ b/compiler/rustc_borrowck/src/dataflow.rs
@@ -222,6 +222,7 @@ fn precompute_borrows_out_of_scope(
     }
 }
 
+// This is `pub` because it's used by unstable external borrowck data users, see `consumers.rs`.
 pub fn calculate_borrows_out_of_scope_at_location<'tcx>(
     body: &Body<'tcx>,
     regioncx: &RegionInferenceContext<'tcx>,