From 8a5b4f19fd6cec7b3ef583afa592fde99dabe58e Mon Sep 17 00:00:00 2001
From: Nathan Weston <nweston@fastmail.com>
Date: Thu, 10 Sep 2015 08:33:29 -0400
Subject: [PATCH] Check for mutable borrow of counter variable

---
 src/loops.rs                   | 2 ++
 tests/compile-fail/for_loop.rs | 4 ++++
 2 files changed, 6 insertions(+)

diff --git a/src/loops.rs b/src/loops.rs
index 06892f6a74e..406fbee0b7c 100644
--- a/src/loops.rs
+++ b/src/loops.rs
@@ -351,6 +351,7 @@ impl<'v, 't> Visitor<'v> for IncrementVisitor<'v, 't> {
                             }
                         },
                     ExprAssign(ref lhs, _) if lhs.id == expr.id => *state = VarState::DontWarn,
+                    ExprAddrOf(mutability,_) if mutability == MutMutable => *state = VarState::DontWarn,
                     _ => ()
                 }
             }
@@ -430,6 +431,7 @@ impl<'v, 't> Visitor<'v> for InitializeVisitor<'v, 't> {
                         } else {
                             VarState::DontWarn
                         }},
+                    ExprAddrOf(mutability,_) if mutability == MutMutable => self.state = VarState::DontWarn,
                     _ => ()
                 }
             }
diff --git a/tests/compile-fail/for_loop.rs b/tests/compile-fail/for_loop.rs
index 3320e9acc1d..d6d73db3c18 100755
--- a/tests/compile-fail/for_loop.rs
+++ b/tests/compile-fail/for_loop.rs
@@ -179,4 +179,8 @@ fn main() {
     let mut _index = 1;
     if false { _index = 0 };
     for _v in &vec { _index += 1 }
+
+    let mut _index = 0;
+    { let mut _x = &mut _index; }
+    for _v in &vec { _index += 1 }
 }