From 671fb4a09d81b2f9fbafb370fe1481b786191c78 Mon Sep 17 00:00:00 2001
From: Enrico Tassi <Enrico.Tassi@Inria.fr>
Date: Mon, 10 Feb 2025 10:17:57 +0100
Subject: [PATCH] be resilient to negative chars

---
 src/elpi_trace_elaborator.ml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/elpi_trace_elaborator.ml b/src/elpi_trace_elaborator.ml
index bec52d0ef..09725c13f 100644
--- a/src/elpi_trace_elaborator.ml
+++ b/src/elpi_trace_elaborator.ml
@@ -235,7 +235,7 @@ let int_of_string s =
 let decode_loc s =
   if Str.(string_match (regexp "File .(context step_id:\\([0-9]+\\))") s 0) then
     `Context (int_of_string (Str.matched_group 1 s))
-  else if Str.(string_match (regexp "File .\\([^,]+\\)., line \\([0-9]+\\), column \\([0-9]+\\), characters? \\([0-9]+\\)-?[0-9]*") s 0) then
+  else if Str.(string_match (regexp "File .\\([^,]+\\)., line \\([0-9]+\\), column \\([0-9]+\\), characters? -*\\([0-9]+\\)-*[0-9]*") s 0) then
     `File {
       filename = Str.matched_group 1 s;
       line = Str.matched_group 2 s |> int_of_string;