From 1c3fd02a4cf1769988ea3f91da54e3c1cacdd9ef Mon Sep 17 00:00:00 2001
From: "Felix S. Klock II" <pnkfelix@pnkfx.org>
Date: Mon, 5 Mar 2018 16:55:27 +0100
Subject: [PATCH] Improve instrumentation for the bug reported during `fn
 report_borrowed_value_does_not_live_long_enough`.

---
 src/librustc_mir/borrow_check/error_reporting.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/librustc_mir/borrow_check/error_reporting.rs b/src/librustc_mir/borrow_check/error_reporting.rs
index 3dc5a7a8490..db2e078586e 100644
--- a/src/librustc_mir/borrow_check/error_reporting.rs
+++ b/src/librustc_mir/borrow_check/error_reporting.rs
@@ -471,7 +471,8 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
             | (RegionKind::ReClosureBound(_), _)
             | (RegionKind::ReCanonical(_), _)
             | (RegionKind::ReErased, _) => {
-                span_bug!(drop_span, "region does not make sense in this context");
+                span_bug!(drop_span, "region {:?} does not make sense in this context",
+                          borrow.region);
             }
         }
     }