From 7ee82cd2dfd8cb226c35c3094423e56c75010377 Mon Sep 17 00:00:00 2001
From: Hugo Herbelin
Date: Sat, 18 Jun 2016 11:23:12 +0200
Subject: Backporting c064fb933 from 8.5 (another regression with Ltac trace
 report).

Doing it explicitly because it is in another file.
---
 ltac/tactic_debug.ml | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/ltac/tactic_debug.ml b/ltac/tactic_debug.ml
index e657eb9bc2..73d04b810d 100644
--- a/ltac/tactic_debug.ml
+++ b/ltac/tactic_debug.ml
@@ -395,14 +395,19 @@ let extract_ltac_trace trace eloc =
   else
     (* We entered a primitive tactic, we don't display trace but
        report on the finest location *)
+    let finer_loc loc1 loc2 = Loc.merge loc1 loc2 = loc2 in
     let best_loc =
-      if not (Loc.is_ghost eloc) then eloc else
-        (* trace is with innermost call coming first *)
-        let rec aux = function
-        | (loc,_)::tail when not (Loc.is_ghost loc) -> loc
-        | _::tail -> aux tail
-        | [] -> Loc.ghost in
-        aux trace in
+      (* trace is with innermost call coming first *)
+      let rec aux best_loc = function
+        | (loc,_)::tail ->
+           if Loc.is_ghost best_loc ||
+              not (Loc.is_ghost loc) && finer_loc loc best_loc
+           then
+             aux loc tail
+           else
+             aux best_loc tail
+        | [] -> best_loc in
+        aux eloc trace in
     None, best_loc
 
 let get_ltac_trace (_, info) =
-- 
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