Extend the implicator so it produces general obligations and also so

that it produces "outlives" relations for associated types. Add
several tests relating to #22246.

src/test/run-pass/regions-issue-22246.rs

@@ -0,0 +1,35 @@
+// Copyright 2015 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.
+
+// Regression test for issue #22246 -- we should be able to deduce
+// that `&'a B::Owned` implies that `B::Owned : 'a`.
+
+#![allow(dead_code)]
+
+use std::ops::Deref;
+
+pub trait ToOwned {
+    type Owned: Borrow<Self>;
+    fn to_owned(&self) -> Self::Owned;
+}
+
+pub trait Borrow<Borrowed> {
+    fn borrow(&self) -> &Borrowed;
+}
+
+pub struct Foo<B:ToOwned> {
+    owned: B::Owned
+}
+
+fn foo<B:ToOwned>(this: &Foo<B>) -> &B {
+    this.owned.borrow()
+}
+
+fn main() { }