Introduce the new phantomdata/phantomfn markers and integrate them

into variance inference; fix various bugs in variance inference
so that it considers the correct set of constraints; modify infer to
consider the results of variance inference for type arguments.

src/test/compile-fail/variance-invariant-arg-object.rs

@@ -0,0 +1,31 @@
+// 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.
+
+#![allow(dead_code)]
+
+trait Get<T> : 'static {
+    fn get(&self, t: T) -> T;
+}
+
+fn get_min_from_max<'min, 'max>(v: Box<Get<&'max i32>>)
+                                -> Box<Get<&'min i32>>
+    where 'max : 'min
+{
+    v //~ ERROR mismatched types
+}
+
+fn get_max_from_min<'min, 'max, G>(v: Box<Get<&'min i32>>)
+                                   -> Box<Get<&'max i32>>
+    where 'max : 'min
+{
+    v //~ ERROR mismatched types
+}
+
+fn main() { }