Future proof the AST for `union`.

5 files changed, 18 insertions, 2 deletions

diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index c0994ccb2ac..fcb99444957 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -1883,6 +1883,10 @@ pub enum ItemKind {
     ///
     /// E.g. `struct Foo<A> { x: A }`
     Struct(VariantData, Generics),
+    /// A union definition (`union` or `pub union`).
+    ///
+    /// E.g. `union Foo<A, B> { x: A, y: B }`
+    Union(VariantData, Generics), // FIXME: not yet implemented
     /// A Trait declaration (`trait` or `pub trait`).
     ///
     /// E.g. `trait Foo { .. }` or `trait Foo<T> { .. }`
@@ -1919,6 +1923,7 @@ impl ItemKind {
             ItemKind::Ty(..) => "type alias",
             ItemKind::Enum(..) => "enum",
             ItemKind::Struct(..) => "struct",
+            ItemKind::Union(..) => "union",
             ItemKind::Trait(..) => "trait",
             ItemKind::Mac(..) |
             ItemKind::Impl(..) |
diff --git a/src/libsyntax/config.rs b/src/libsyntax/config.rs
index ff1ecd44371..69a97917652 100644
--- a/src/libsyntax/config.rs
+++ b/src/libsyntax/config.rs
@@ -180,6 +180,9 @@ impl<'a> fold::Folder for StripUnconfigured<'a> {
             ast::ItemKind::Struct(def, generics) => {
                 ast::ItemKind::Struct(fold_struct(self, def), generics)
             }
+            ast::ItemKind::Union(def, generics) => {
+                ast::ItemKind::Union(fold_struct(self, def), generics)
+            }
             ast::ItemKind::Enum(def, generics) => {
                 let variants = def.variants.into_iter().filter_map(|v| {
                     self.configure(v).map(|v| {
diff --git a/src/libsyntax/fold.rs b/src/libsyntax/fold.rs
index fad0b6f65a7..7500bfe9caa 100644
--- a/src/libsyntax/fold.rs
+++ b/src/libsyntax/fold.rs
@@ -885,6 +885,10 @@ pub fn noop_fold_item_kind<T: Folder>(i: ItemKind, folder: &mut T) -> ItemKind {
             let struct_def = folder.fold_variant_data(struct_def);
             ItemKind::Struct(struct_def, folder.fold_generics(generics))
         }
+        ItemKind::Union(struct_def, generics) => {
+            let struct_def = folder.fold_variant_data(struct_def);
+            ItemKind::Union(struct_def, folder.fold_generics(generics))
+        }
         ItemKind::DefaultImpl(unsafety, ref trait_ref) => {
             ItemKind::DefaultImpl(unsafety, folder.fold_trait_ref((*trait_ref).clone()))
         }
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index 99c00789219..8563d27908d 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -1251,7 +1251,10 @@ impl<'a> State<'a> {
                 try!(self.head(&visibility_qualified(&item.vis, "struct")));
                 try!(self.print_struct(&struct_def, generics, item.ident, item.span, true));
             }
-
+            ast::ItemKind::Union(ref struct_def, ref generics) => {
+                try!(self.head(&visibility_qualified(&item.vis, "union")));
+                try!(self.print_struct(&struct_def, generics, item.ident, item.span, true));
+            }
             ast::ItemKind::DefaultImpl(unsafety, ref trait_ref) => {
                 try!(self.head(""));
                 try!(self.print_visibility(&item.vis));
diff --git a/src/libsyntax/visit.rs b/src/libsyntax/visit.rs
index b2d47996659..efd9b027504 100644
--- a/src/libsyntax/visit.rs
+++ b/src/libsyntax/visit.rs
@@ -278,7 +278,8 @@ pub fn walk_item<V: Visitor>(visitor: &mut V, item: &Item) {
             visitor.visit_ty(typ);
             walk_list!(visitor, visit_impl_item, impl_items);
         }
-        ItemKind::Struct(ref struct_definition, ref generics) => {
+        ItemKind::Struct(ref struct_definition, ref generics) |
+        ItemKind::Union(ref struct_definition, ref generics) => {
             visitor.visit_generics(generics);
             visitor.visit_variant_data(struct_definition, item.ident,
                                      generics, item.id, item.span);