From 06e130fb241cf3c828040d7d4958bf1945226e9c Mon Sep 17 00:00:00 2001
From: Simon Sapin <simon.sapin@exyr.org>
Date: Mon, 17 Jul 2017 14:32:37 +0200
Subject: [PATCH] Use checked NonZero constructor in MIR move path indices
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… to protect against UB in the unlikely case that `idx + 1` overflows.
---
 src/librustc_mir/dataflow/move_paths/mod.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/librustc_mir/dataflow/move_paths/mod.rs b/src/librustc_mir/dataflow/move_paths/mod.rs
index 63c204fbdcda..dd970fdff91e 100644
--- a/src/librustc_mir/dataflow/move_paths/mod.rs
+++ b/src/librustc_mir/dataflow/move_paths/mod.rs
@@ -42,7 +42,7 @@ pub(crate) mod indexes {
 
             impl Idx for $Index {
                 fn new(idx: usize) -> Self {
-                    unsafe { $Index(NonZero::new_unchecked(idx + 1)) }
+                    $Index(NonZero::new(idx + 1).unwrap())
                 }
                 fn index(self) -> usize {
                     self.0.get() - 1