From 7bd19112ee30925b636ebbe26de9e043b47cb67f Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Mon, 12 Jan 2015 10:20:14 -0500
Subject: [PATCH] Patch variance bug: appearing in a binding is an invariant
 position (at least right now).

---
 src/librustc_typeck/variance.rs               |  6 +++++
 .../compile-fail/variance-object-types.rs     | 24 +++++++++++++++++++
 2 files changed, 30 insertions(+)
 create mode 100644 src/test/compile-fail/variance-object-types.rs

diff --git a/src/librustc_typeck/variance.rs b/src/librustc_typeck/variance.rs
index ed8a50110e5a..63ad47ff31f6 100644
--- a/src/librustc_typeck/variance.rs
+++ b/src/librustc_typeck/variance.rs
@@ -818,6 +818,12 @@ impl<'a, 'tcx> ConstraintContext<'a, 'tcx> {
                     trait_def.generics.regions.get_slice(subst::TypeSpace),
                     trait_ref.substs(),
                     variance);
+
+                let projections = data.projection_bounds_with_self_ty(self.tcx(),
+                                                                      self.tcx().types.err);
+                for projection in projections.iter() {
+                    self.add_constraints_from_ty(generics, projection.0.ty, self.invariant);
+                }
             }
 
             ty::ty_param(ref data) => {
diff --git a/src/test/compile-fail/variance-object-types.rs b/src/test/compile-fail/variance-object-types.rs
new file mode 100644
index 000000000000..972ec96f5f27
--- /dev/null
+++ b/src/test/compile-fail/variance-object-types.rs
@@ -0,0 +1,24 @@
+// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Test that Cell is considered invariant with respect to its
+// type.
+
+use std::cell::Cell;
+
+// For better or worse, associated types are invariant, and hence we
+// get an invariant result for `'a`.
+#[rustc_variance]
+struct Foo<'a> { //~ ERROR regions=[[o];[];[]]
+    x: Box<Fn(i32) -> &'a i32 + 'static>
+}
+
+fn main() {
+}