From 3e33e54b5be77d03df0962291f1480cc3876544d Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Thu, 23 May 2019 11:03:04 +0200
Subject: [PATCH] hopefully improve error message a bit

---
 src/stacked_borrows.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/stacked_borrows.rs b/src/stacked_borrows.rs
index be6bec60cfd..e76747ef807 100644
--- a/src/stacked_borrows.rs
+++ b/src/stacked_borrows.rs
@@ -383,7 +383,7 @@ impl<'tcx> Stack {
         // We use that to determine where to put the new item.
         let granting_idx = self.find_granting(access, derived_from)
             .ok_or_else(|| InterpError::MachineError(format!(
-                "no item to reborrow for {:?} from tag {} found in borrow stack", new.perm, derived_from,
+                "trying to reborrow for {:?}, but parent tag {} does not have an appropriate item in the borrow stack", new.perm, derived_from,
             )))?;
 
         // Compute where to put the new item.