From c61a0092bc236c4be4cb691fcd50ff50e91ab0d6 Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Fri, 26 Dec 2014 03:30:51 -0500
Subject: Fix orphan checking (cc #19470). (This is not a complete fix of
 #19470 because of the backwards compatibility feature gate.)

This is a [breaking-change]. The new rules require that, for an impl of a trait defined
in some other crate, two conditions must hold:

1. Some type must be local.
2. Every type parameter must appear "under" some local type.

Here are some examples that are legal:

```rust
struct MyStruct<T> { ... }

// Here `T` appears "under' `MyStruct`.
impl<T> Clone for MyStruct<T> { }

// Here `T` appears "under' `MyStruct` as well. Note that it also appears
// elsewhere.
impl<T> Iterator<T> for MyStruct<T> { }
```

Here is an illegal example:

```rust
// Here `U` does not appear "under" `MyStruct` or any other local type.
// We call `U` "uncovered".
impl<T,U> Iterator<U> for MyStruct<T> { }
```

There are a couple of ways to rewrite this last example so that it is
legal:

1. In some cases, the uncovered type parameter (here, `U`) should be converted
   into an associated type. This is however a non-local change that requires access
   to the original trait. Also, associated types are not fully baked.
2. Add `U` as a type parameter of `MyStruct`:
   ```rust
   struct MyStruct<T,U> { ... }
   impl<T,U> Iterator<U> for MyStruct<T,U> { }
   ```
3. Create a newtype wrapper for `U`
   ```rust
   impl<T,U> Iterator<Wrapper<U>> for MyStruct<T,U> { }
   ```

Because associated types are not fully baked, which in the case of the
`Hash` trait makes adhering to this rule impossible, you can
temporarily disable this rule in your crate by using
`#![feature(old_orphan_check)]`. Note that the `old_orphan_check`
feature will be removed before 1.0 is released.
---
 src/libserialize/json.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'src/libserialize/json.rs')

diff --git a/src/libserialize/json.rs b/src/libserialize/json.rs
index 3f0d59c319a..684856ae33b 100644
--- a/src/libserialize/json.rs
+++ b/src/libserialize/json.rs
@@ -81,7 +81,7 @@
 //! use serialize::json;
 //!
 //! // Automatically generate `Decodable` and `Encodable` trait implementations
-//! #[deriving(Decodable, Encodable)]
+//! #[deriving(RustcDecodable, RustcEncodable)]
 //! pub struct TestStruct  {
 //!     data_int: u8,
 //!     data_str: String,
-- 
cgit 1.4.1-3-g733a5


From 5c34781a7d3f5b6761fa564a4a9ebeb19bb50cc1 Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Thu, 1 Jan 2015 16:45:22 -0500
Subject: Disable the JSON doctests because they don't pass the new coherence
 rules and cannot be updated until the libraries are synced, nor can they opt
 in to the old semantics.

---
 src/libserialize/json.rs | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

(limited to 'src/libserialize/json.rs')

diff --git a/src/libserialize/json.rs b/src/libserialize/json.rs
index 684856ae33b..a734630a215 100644
--- a/src/libserialize/json.rs
+++ b/src/libserialize/json.rs
@@ -76,7 +76,8 @@
 //! Create a struct called `TestStruct` and serialize and deserialize it to and from JSON using the
 //! serialization API, using the derived serialization code.
 //!
-//! ```rust
+//! ```notrust
+//! // FIXME(#19470): this cannot be ```rust``` because it fails orphan checking at the moment
 //! extern crate serialize;
 //! use serialize::json;
 //!
@@ -110,7 +111,8 @@
 //!
 //! ### Simple example of `ToJson` usage
 //!
-//! ```rust
+//! ```notrust
+//! // FIXME(#19470): this cannot be ```rust``` because it fails orphan checking at the moment
 //! extern crate serialize;
 //! use serialize::json::{mod, ToJson, Json};
 //!
@@ -149,7 +151,8 @@
 //!
 //! ### Verbose example of `ToJson` usage
 //!
-//! ```rust
+//! ```notrust
+//! // FIXME(#19470): this cannot be ```rust``` because it fails orphan checking at the moment
 //! extern crate serialize;
 //! use std::collections::BTreeMap;
 //! use serialize::json::{mod, Json, ToJson};
-- 
cgit 1.4.1-3-g733a5