Rollup merge of #67114 - Centril:foreign-item-alias, r=petrochenkov

Make `ForeignItem` an alias of `Item`.

Working towards the merging of items in AST and syntactically.

r? @petrochenkov

src/librustc_parse/parser/item.rs

@@ -1181,6 +1181,7 @@ pub fn parse_foreign_item(&mut self, extern_sp: Span) -> PResult<'a, ForeignItem
                         attrs,
                         vis: visibility,
                         kind: ForeignItemKind::Macro(mac),
+                        tokens: None,
                     }
                 )
             }
@@ -1211,6 +1212,7 @@ fn parse_item_foreign_static(&mut self, vis: ast::Visibility, lo: Span, attrs: V
             id: DUMMY_NODE_ID,
             span: lo.to(hi),
             vis,
+            tokens: None,
         })
     }
 
@@ -1228,7 +1230,8 @@ fn parse_item_foreign_type(&mut self, vis: ast::Visibility, lo: Span, attrs: Vec
             kind: ForeignItemKind::Ty,
             id: DUMMY_NODE_ID,
             span: lo.to(hi),
-            vis
+            vis,
+            tokens: None,
         })
     }
 
@@ -1826,6 +1829,7 @@ fn parse_item_foreign_fn(
             id: DUMMY_NODE_ID,
             span,
             vis,
+            tokens: None,
         })
     }
 

src/libsyntax/ast.rs

@@ -2488,14 +2488,14 @@ pub fn ctor_id(&self) -> Option<NodeId> {
 ///
 /// The name might be a dummy name in case of anonymous items.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
-pub struct Item {
+pub struct Item<K = ItemKind> {
     pub attrs: Vec<Attribute>,
     pub id: NodeId,
     pub span: Span,
     pub vis: Visibility,
     pub ident: Ident,
 
-    pub kind: ItemKind,
+    pub kind: K,
 
     /// Original tokens this item was parsed from. This isn't necessarily
     /// available for all items, although over time more and more items should
@@ -2650,16 +2650,7 @@ pub fn descriptive_variant(&self) -> &str {
     }
 }
 
-#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
-pub struct ForeignItem {
-    pub attrs: Vec<Attribute>,
-    pub id: NodeId,
-    pub span: Span,
-    pub vis: Visibility,
-    pub ident: Ident,
-
-    pub kind: ForeignItemKind,
-}
+pub type ForeignItem = Item<ForeignItemKind>;
 
 /// An item within an `extern` block.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]

src/libsyntax/mut_visit.rs

@@ -1053,7 +1053,7 @@ pub fn noop_flat_map_item<T: MutVisitor>(mut item: P<Item>, visitor: &mut T)
 pub fn noop_flat_map_foreign_item<T: MutVisitor>(mut item: ForeignItem, visitor: &mut T)
     -> SmallVec<[ForeignItem; 1]>
 {
-    let ForeignItem { ident, attrs, kind, id, span, vis } = &mut item;
+    let ForeignItem { ident, attrs, id, kind, vis, span, tokens: _ } = &mut item;
     visitor.visit_ident(ident);
     visit_attrs(attrs, visitor);
     match kind {

src/libsyntax_expand/placeholders.rs

@@ -65,6 +65,7 @@ fn mac_placeholder() -> ast::Mac {
             AstFragment::ForeignItems(smallvec![ast::ForeignItem {
                 id, span, ident, vis, attrs,
                 kind: ast::ForeignItemKind::Macro(mac_placeholder()),
+                tokens: None,
             }]),
         AstFragmentKind::Pat => AstFragment::Pat(P(ast::Pat {
             id, span, kind: ast::PatKind::Mac(mac_placeholder()),