From abeebfedc8602f97cc01855b2d6692de3e471f2b Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Tue, 30 Oct 2018 13:03:22 -0400
Subject: [PATCH] improve the error message here

---
 src/derived.rs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/derived.rs b/src/derived.rs
index 64ab6ba1..4e6db0f4 100644
--- a/src/derived.rs
+++ b/src/derived.rs
@@ -631,7 +631,12 @@ where
                 // has gone horribly wrong. This panic will
                 // (unfortunately) abort the process, but recovery is
                 // not possible.
-                _ => panic!("unexpected query state"),
+                _ => panic!(
+                    "\
+Unexpected panic during query evaluation, aborting the process.
+
+Please report this bug to https://github.com/salsa-rs/salsa/issues."
+                ),
             }
         } else {
             // If no panic occurred, then panic guard ought to be