Fix a bug in the opt-in-copy work: it was failing to liberate the regions bound in the impl before searching for `Copy` implements for all fields, leading to problems in the "copyability check". Basically the copyability check would wind up looking for an impl of `for<'tcx> Foo<&'tcx T>`. The impl that exists however is `impl<T> Copy for Foo<T>` and the current rules do not consider that a match (something I would like to revise in a later PR).

1 files changed, 38 insertions, 0 deletions

diff --git a/src/test/run-pass/hrtb-opt-in-copy.rs b/src/test/run-pass/hrtb-opt-in-copy.rs
new file mode 100644
index 00000000000..b6bba363e72
--- /dev/null
+++ b/src/test/run-pass/hrtb-opt-in-copy.rs
@@ -0,0 +1,38 @@
+// 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.
+
+// Test that we handle binder levels correctly when checking whether a
+// type can implement `Copy`. In particular, we had a bug where we failed to
+// liberate the late-bound regions from the impl, and thus wound up
+// searching for an impl of `for<'tcx> Foo<&'tcx T>`. The impl that
+// exists however is `impl<T> Copy for Foo<T>` and the current rules
+// did not consider that a match (something I would like to revise in
+// a later PR).
+
+#![allow(dead_code)]
+
+use std::kinds::marker;
+
+#[deriving(Copy)]
+struct Foo<T> { x: T }
+
+type Ty<'tcx> = &'tcx TyS<'tcx>;
+
+enum TyS<'tcx> {
+    Boop(marker::InvariantLifetime<'tcx>)
+}
+
+enum Bar<'tcx> {
+    Baz(Foo<Ty<'tcx>>)
+}
+
+impl<'tcx> Copy for Bar<'tcx> { }
+
+fn main() { }