Patch variance bug: appearing in a binding is an invariant position (at least right now).

Author: nikomatsakis

src/librustc_typeck/variance.rs

@@ -814,6 +814,12 @@ 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) => {

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() {
+}