From ebbaf4611a9605412d2aa31c8ebaf0745557fff0 Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Tue, 11 Feb 2020 10:14:50 +0100
Subject: [PATCH] simplify_try: address some of eddyb's comments

---
 src/librustc_mir/transform/simplify_try.rs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/librustc_mir/transform/simplify_try.rs b/src/librustc_mir/transform/simplify_try.rs
index bd661195a4852..3f28f033047a2 100644
--- a/src/librustc_mir/transform/simplify_try.rs
+++ b/src/librustc_mir/transform/simplify_try.rs
@@ -52,6 +52,8 @@ impl<'tcx> MirPass<'tcx> for SimplifyArmIdentity {
                 Some(x) => x,
             };
             if local_tmp_s0 != local_tmp_s1
+                // Avoid moving into ourselves.
+                || local_0 == local_1
                 // The field-and-variant information match up.
                 || vf_s0 != vf_s1
                 // Source and target locals have the same type.
@@ -64,6 +66,7 @@ impl<'tcx> MirPass<'tcx> for SimplifyArmIdentity {
             }
 
             // Right shape; transform!
+            s0.source_info = s2.source_info;
             match &mut s0.kind {
                 StatementKind::Assign(box (place, rvalue)) => {
                     *place = local_0.into();