From b00db7c75b85d521a17372750512111657baaea2 Mon Sep 17 00:00:00 2001
From: "Felix S. Klock II" <pnkfelix@pnkfx.org>
Date: Mon, 5 Mar 2018 16:54:20 +0100
Subject: [PATCH] Instrument `statement_effect_on_borrows` for the `lhs =
 &place` case.

---
 src/librustc_mir/dataflow/impls/borrows.rs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/librustc_mir/dataflow/impls/borrows.rs b/src/librustc_mir/dataflow/impls/borrows.rs
index a21691813a4..098ad8e558f 100644
--- a/src/librustc_mir/dataflow/impls/borrows.rs
+++ b/src/librustc_mir/dataflow/impls/borrows.rs
@@ -179,8 +179,14 @@ impl<'a, 'gcx, 'tcx> BitDenotation for Borrows<'a, 'gcx, 'tcx> {
                     if let RegionKind::ReEmpty = region {
                         // If the borrowed value dies before the borrow is used, the region for
                         // the borrow can be empty. Don't track the borrow in that case.
+                        debug!("Borrows::statement_effect_on_borrows \
+                                location: {:?} stmt: {:?} has empty region, killing {:?}",
+                               location, stmt.kind, index);
                         sets.kill(&index);
                         return
+                    } else {
+                        debug!("Borrows::statement_effect_on_borrows location: {:?} stmt: {:?}",
+                               location, stmt.kind);
                     }
 
                     assert!(self.borrow_set.region_map.get(region).unwrap_or_else(|| {