Add some more test coverage of by-ref unboxed closures

src/test/compile-fail/unboxed-closure-region.rs

+// Copyright 2014 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.
+
+#![feature(unboxed_closures)]
+
+// Test that an unboxed closure that captures a free variable by
+// reference cannot escape the region of that variable.
+fn main() {
+    let _f = {
+        let x = 0u;
+        |:| x //~ ERROR cannot infer an appropriate lifetime due to conflicting requirements
+    };
+}

src/test/compile-fail/unboxed-closures-borrow-conflict.rs

+// Copyright 2014 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.
+
+#![feature(unboxed_closures)]
+
+// Test that an unboxed closure that mutates a free variable will
+// cause borrow conflicts.
+
+fn main() {
+    let mut x = 0u;
+    let f = |:| x += 1;
+    let _y = x; //~ ERROR cannot use `x` because it was mutably borrowed
+}

src/test/run-pass/unboxed-closures-by-ref.rs

+// Copyright 2014 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.
+
+#![feature(overloaded_calls, unboxed_closures)]
+
+// Test by-ref capture of environment in unboxed closure types
+
+fn call_fn<F: Fn()>(f: F) {
+    f()
+}
+
+fn call_fn_mut<F: FnMut()>(mut f: F) {
+    f()
+}
+
+fn call_fn_once<F: FnOnce()>(f: F) {
+    f()
+}
+
+fn main() {
+    let mut x = 0u;
+    let y = 2u;
+
+    call_fn(|&:| x += y);
+    call_fn_mut(|&mut:| x += y);
+    call_fn_once(|:| x += y);
+    assert_eq!(x, y * 3);
+}