privacy: walk associated types in trait impls

src/test/compile-fail/issue-22912.rs

@@ -0,0 +1,41 @@
+// 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.
+
+pub struct PublicType;
+struct PrivateType;
+
+pub trait PublicTrait {
+    type Item;
+}
+
+trait PrivateTrait {
+    type Item;
+}
+
+impl PublicTrait for PublicType {
+    type Item = PrivateType;  //~ ERROR private type in exported type signature
+}
+
+// OK
+impl PublicTrait for PrivateType {
+    type Item = PrivateType;
+}
+
+// OK
+impl PrivateTrait for PublicType {
+    type Item = PrivateType;
+}
+
+// OK
+impl PrivateTrait for PrivateType {
+    type Item = PrivateType;
+}
+
+fn main() {}