auto merge of #20285 : FlaPer87/rust/oibit-send-and-friends, r=nikomatsakis

This commit introduces the syntax for negative implementations of traits
as shown below:

`impl !Trait for Type {}`

cc #13231
Part of RFC rust-lang/rfcs#127

r? @nikomatsakis 

2 files changed, 2 insertions, 1 deletions

diff --git a/src/libsyntax/ext/deriving/generic/mod.rs b/src/libsyntax/ext/deriving/generic/mod.rs
index 8863de8757b..459abf15b33 100644
--- a/src/libsyntax/ext/deriving/generic/mod.rs
+++ b/src/libsyntax/ext/deriving/generic/mod.rs
@@ -488,6 +488,7 @@ impl<'a> TraitDef<'a> {
             ident,
             a,
             ast::ItemImpl(ast::Unsafety::Normal,
+                          ast::ImplPolarity::Positive,
                           trait_generics,
                           opt_trait_ref,
                           self_type,
diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index e65ecc19ea1..b3f30dd4581 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -1111,7 +1111,7 @@ impl<'a, 'b> Folder for MacroExpander<'a, 'b> {
 
     fn fold_item(&mut self, item: P<ast::Item>) -> SmallVector<P<ast::Item>> {
         let prev_type = self.current_impl_type.clone();
-        if let ast::Item_::ItemImpl(_, _, _, ref ty, _) = item.node {
+        if let ast::Item_::ItemImpl(_, _, _, _, ref ty, _) = item.node {
             self.current_impl_type = Some(ty.clone());
         }